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NNadir

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Refractive Lens for Extreme UV Radiation Discovered.

The paper I'll discuss in this post is this one: Extreme-ultraviolet refractive optics| Extreme-ultraviolet refractive optics (L. Drescher, O. Kornilov, T. Witting, G. Reitsma, N. Monserud, A. Rouzée, J. Mikosch, M. J. J. Vrakking & B. Schütte, Nature 564, 91–94 (2018) )

Lenses for focusing extreme UV light - just short of x-rays in energy - do not exist. One can imagine many applications for this capability, for instance in materials etching, welding and other processing, spectroscopic investigations of the structure of matter, cancer and other surgeries (should the focusing be refined enough - hard to see here since the lenses are gases) and regrettably, as no discovery is free of possible sinister use, weapons systems.

The introductory text tells the story better than I can:

Refraction of light is omnipresent in nature, where it forms the basis for the functionality of the human eye and the observation of a rainbow. It is exploited in many applications in the visible, infrared and ultraviolet spectral regions. For instance, refractive errors of the eye are corrected by glasses or contact lenses, and optical microscopes enable the magnification of small objects or structures. In the context of laser physics, refractive lenses are extensively used to focus or (de-)magnify laser beams. Dispersion and deflection of light by optical prisms is used to compress or stretch ultrashort laser pulses.

When Röntgen discovered X-rays in 1895, he attempted refraction experiments using prisms and lenses8. Because he observed no significant deflection of the X-rays, he concluded that refractive lenses were not suitable for focusing X-ray radiation. A century later, a compound refractive lens consisting of a lens array was nevertheless developed for the hard X-ray regime, assisted by the comparably low absorption in this spectral region. Compound refractive lenses are used to focus X-rays emitted from modern synchrotron9 and free-electron laser facilities10,11. They have been applied for hard X-ray microscopy12, for X-ray nanofocusing13 and for the investigation of crystal scattering14, as well as for coherent diffractive imaging of nanoscale samples15.

Refractive elements have so far been missing in the extreme-ultraviolet (XUV) range but are highly desirable. For instance, refractive lenses could be used to focus XUV pulses without changing the propagation direction, thereby providing considerable flexibility. The use of specially designed microscopic refractive lenses has been proposed16,17. However, the need to use very thin lenses with a sophisticated design, owing to the strong absorption of XUV radiation, makes practical implementation challenging.

Here, we demonstrate that control over the refraction of XUV pulses can be achieved by using gases instead of solids. We exploit the fact that close to atomic resonances, the refractive index n has a dispersive lineshape, as depicted in the top part of Fig. 1a.


The authors utilize gas jets to focus the XUV beams using density gradients in the gas pulses. Since (in this case) the gases are monoatomic noble gases, they cannot be damaged by the energy that is contained in extreme UV radiation, as is the case with solid phase lenses.

If interested, take a look at the pictures.

Figure 1:



The caption:

a, Top, dispersive lineshape of the refractive index in the vicinity of an atomic resonance. Spectral components at photon energies below the resonance (n > 1) are indicated in red, components at energies above the resonance (n < 1) in blue. Middle, experimental configuration, showing an XUV pulse (violet arrow) that crosses a gas jet (black arrow), which has a density gradient in the vertical direction (orange arrow), at right angles. Bottom, deflection of an XUV pulse propagating below the centre of the gas jet. b, Angle-resolved spectrum of a broadband HHG pulse measured in the absence of the gas jet. The angular divergence of the XUV beam in the vertical direction is reflected in the spatial distribution along the vertical axis. arb. units, arbitrary units. c, The same spectrum after propagation at a distance of 0.3 mm below the centre of a dense He gas jet (generated using a backing pressure of 10 bar) shows clear signatures of refraction. Spectral components with photon energies below the 1s np resonances of He are deflected upwards, whereas spectral components above these resonances are deflected downwards. The deflection angles are largest close to the 1s 2p resonance and decrease for higher resonances, owing to the decreasing oscillator strengths. Above the ionization potential of He (at 24.58 eV), the XUV radiation is strongly absorbed. Owing to ageing effects, the sensitivity of the detector was reduced in regions where the undisturbed HHG spectrum is recorded (as in b) compared with regions where the deflected XUV radiation is observed. This makes the deflected XUV radiation appear more intense. d, Simulation of the XUV refraction in an inhomogeneous He gas jet, taking into account 1s np resonances with n = 2, 3, …, 8. The simulation indicates that for a backing pressure of 10 bar, a gas jet with a peak density of 9 × 10^19 atoms cm−3 (corresponding to a pressure of 3.7 bar at 300 K) was achieved in the interaction zone.



Figure 2:



The caption:

a–c, Angle-resolved XUV spectra after propagation at a distance of 0.3 mm below the centre of a He gas jet, for backing pressures of 1 bar (a), 3 bar (b) and 9 bar (c). d, The average deflection angle as a function of the photon energy for backing pressures of 3 bar (corresponding to a peak pressure in the interaction zone of about 1 bar; cyan solid curve) and 9 bar (orange solid curve). Here the vertical scale on the left axis applies, as indicated by the upper arrow. For comparison, the calculated refractivity (that is, n − 1) at standard temperature (273.15 K) and standard pressure (1 bar) is plotted on top of the deflection results (blue dotted curve). The vertical scale on the right axis applies, as indicated by the lower arrow. Note that the calculated refractivity is proportional to the pressure. The brown dotted curve shows the calculated refractivity multiplied by a factor of 3.


Image 3 (focused XUV radiation):



a, Spatially resolved spectrum of unfocused XUV radiation at 20.2 eV (corresponding to the 13th harmonic). b, c, The divergence of this harmonic is altered after propagation through a He gas jet (see inset of d), as shown for backing pressures of 6 bar (b) and 12 bar (c). d, Comparison of the vertical beam profiles using backing pressures of 0 bar (blue curve) and 12 bar (red curve). The inset shows the pressure-dependent spot size, where the error bars reflect the uncertainties in determining the spot sizes. e, Spatially resolved spectrum of radiation at 14.0 eV (corresponding to the ninth harmonic), which is close to the 3d and 5s resonances of Ar. f, Focusing of this harmonic is achieved by an Ar gas jet at a backing pressure of 2.5 bar. g, When further increasing the backing pressure to 4 bar, an increasing beam size is observed, because the Ar lens focuses the XUV beam between the gas jet and the detector. h, The vertical beam profiles for Ar backing pressures of 0 bar (blue curve) and 2.5 bar (red curve). The inset shows the pressure-dependent spot size, where the error bars reflect the uncertainties in determining the spot sizes.


Fig. 4: Simulation of the XUV focus:



The caption:

a, Simulated focus in the vertical direction as a function of the photon energy following propagation of an XUV pulse at 14.0 eV (1.9 mm FWHM diameter) through an Ar gas jet with a peak density of 2.2 × 1019 atoms cm−3 (corresponding to a pressure of 0.9 bar at 300 K). Because of chromatic aberration, the XUV spot size depends on the photon energy. b, Spot size as a function of the Ar gas density for XUV pulses with a bandwidth of 160 meV (black curve) and 2 meV (red curve), showing minimal spot sizes of 74 μm and 40 μm, respectively. c, The chromatic aberration is reduced for photon energies that are further away from the resonance. This is shown for the example of an XUV pulse at 20.2 eV (2.4 mm FWHM diameter) that propagates through a He gas jet with a peak density of 1.1 × 1020 atoms cm−3 (corresponding to a pressure of 4.3 bar at 300 K). d, Spot size as a function of He gas density for XUV pulses with a bandwidth of 240 meV (black curve) and 2 meV (red curve), which exhibit minimal spot sizes of 28 μm and 20 μm.


The authors conclude:

In conclusion, we have presented a method to deflect and focus XUV pulses by using the inhomogeneity of a gas jet placed in the way of an XUV beam. Our results enable the transfer of concepts based on refractive optics that are widely used in other spectral regions to the XUV regime, including microscopy, nanofocusing and the compression of ultrashort pulses. XUV gas-based lenses have several advantages, including their high transmission, deformability and tunability (by varying the gas composition, the gas pressure and the gas jet geometry)...

...Refractive XUV gas-phase lenses can be designed for photon energies between 10 eV and 24 eV by carefully selecting appropriate atoms or molecules for different photon energies. In the future, this range might be extended to higher photon energies by developing lenses that exploit refraction in an inhomogeneous plasma consisting of highly charged ions and electrons.


Esoteric, but interesting.

Have a pleasant day tomorrow.

The Molecular Biology of Methicillin Resistant Staphylococcus Aureus Involves Sugar Chemistry.

The paper I'll discuss in this post is this one: Methicillin-resistant Staphylococcus aureus alters cell wall glycosylation to evade immunity. (Peschel, Stehel et al Nature 563, pages705–709 (2018) )

A kind of mental block I've had over the years involves my understanding of the complex chemistry and biochemistry of sugars.

I've always found it hard, and tend to squirrel around it when it comes before me.

It's why I always love to read the introductory text of Gabius' The Sugar Code which I'm sure I've referenced before in this space.

To wit:

Teaching the biochemistry of carbohydrates is not simply an exercise in terminology. It has much more to offer than commonly touched upon in basic courses, if we deliberately pay attention to the far-reaching potential of sugars beyond energy metabolism and cell wall stability. In fact, then there is no reason why complex carbohydrates should shy at competition with nucleic acids and proteins for the top spot in high-density biocoding. On the contrary, sugars have ideal properties for this purpose, as will be concluded at the end of this chapter. In this sense, an obvious explanation why research in glycosciences (structural and functional glycomics and lectinomics) has lagged behind the fields of genomics and proteomics, also in the public eye, is 'that glycoconjugates are much more complex, variegated, and diffiailt to study than proteins and nucleic acids' [1]. What is a boon for decorating cell surfaces with a maximum number of molecular messages at the same time has been and still is a demanding challenge for analytical and synthetic chemistry…


H.J. Gabius ed. The Sugar Code, Wiley, 2009 pg 1.

That about sums it up. People don't think about sugars too much, because it's hard to do so...

(It's a great book by the way. I have to reference it all the time.)

One of the great - among many - challenges for future generations is antibiotic resistance. The extension of life span around the world is to a large measure the existence of antibiotics. My grandmother died at the age of 39 from a simple infection that could be cured today with a trip to the doctor, a prescription, and maybe 20 or 30 pills.

In order to address this rising crisis, it is useful to know how bacterial evolve to develop resistance to drugs, and, for that matter, natural antibodies.

This is why I found the paper cited above quite interesting.

From the introduction:

Novel prevention and treatment strategies against major antibiotic-resistant pathogens such as MRSA are urgently needed but are not within reach because some of the most critical virulence strategies of these pathogens are not understood8. The pathogenic potential of prominent healthcare-associated (HA)-MRSA and recently emerged livestock-associated (LA)-MRSA strains is thought to rely on particularly effective immune evasion strategies, whereas community-associated (CA)-MRSA strains often produce more aggressive toxins1,2. Most humans have high overall levels of antibodies against S. aureus as a consequence of preceding infections, but antibody titres differ strongly for specific antigens and are often not protective in immunocompromised patients, for reasons that are not clear3. A large percentage of human antibodies against S. aureus is directed against WTA5,9,10, which is largely invariant. However, some S. aureus lineages produce altered WTA, which modulates, for instance, phage susceptibility 7,11...


WTA is "Wall teichoic acid."

Teichoic acid, like nucleic "acid" is actually a copolymer.of a doubly phosphorylated acetylated aminosugar, galactosamine, and glycerol (or ribotol, an alcohol formed by reducing ribose.)

Here's a structure from Wikipedia:



The authors identified a protein called "TarP" that has close homology (27%) to a protein found in "normal" (not resistant) staphylococcus TarS. When they reinserted TarS into resistant strains, they found that they could restore susceptibility to antibiotics, as well as manipulate susceptibility to certain viruses.

I don't have a lot of time tonight, but here's some pictures and captions from the paper:



The caption:

a, TarP is encoded next to different integrase types (int gene) in prophages φtarP-Sa3int (with immune evasion cluster scn, chp, sak, sep), found in HA-MRSA, and φtarP-Sa1int and φtarP-Sa9int, identified in LA-MRSA. TarP variants in φtarP-Sa1int and φtarP-Sa9int differed from TarP in φtarP-Sa3int in one amino acid each (I8M and D296N, respectively). Both residues are distant from the catalytic centre. b, Complementation of S. aureus RN4420 ΔtarM/S with either tarS or tarP restores susceptibility to infection by WTA GlcNAc-binding siphophages, as indicated by plaque formation on bacterial lawns. Data shown are representative of three independent experiments. c, tarP expression reduces siphophage Φ11-mediated transfer of SaPIbov in N315. Values indicate the ratio of transduction units (TrU) to plaque-forming units (PFU) given as mean ± s.d. of three independent experiments. Statistical significances when compared to wild type were calculated by one-way ANOVA with Dunnett’s post-test (two-sided) and significant P values (P ≤ 0.05) are indicated. NO (none obtained) indicates no obtained transductants.


Some protein structures, teichoic acid structures, and some NMR's:



The caption:

a, Expression of tarP renders N315 resistant to podophages. Representative data from three independent experiments are shown. b, 1H NMR spectra reveal different ribitol hydroxyl glycosylation of N315 WTA by TarS (C4) or TarP (C3). The RboP units with attached GlcNAc are depicted above the corresponding proton resonances. Representative data from three experiments are shown. In-depth description of the structural motifs identified in the spectra is given in the Supplementary Information. c, Crystal structure of TarP homotrimer (pink, orange, grey) bound to UDP-GlcNAc (yellow) and two Mn2+ ions (lime green). The nucleotide-binding domain (NBD), acceptor-binding domain (ABD), and C-terminal trimerization domain (CTD) of the pink monomer are labelled. d, Views into the trimer interface (boxed in c). Left, polar interactions. Hydrogen bonds and salt bridges are shown as black dashed lines. The Mn2+ is 2.1 Å from each Asp316 carboxylate. Right, hydrophobic interactions, with the mutated residue Ile322 highlighted in red. e, Size-exclusion chromatography elution profiles. Based on calibration of the column, the TarP wild-type and I322E mutant proteins have estimated molecular weights of 138 kDa (n = 8) and 42 kDa (n = 3), respectively, in agreement with the calculated molecular weights of 120 kDa for a TarP trimer and 40 kDa for monomeric TarP.


A cartoon of interactions leading to the modified cell walss:



a, 3RboP binding site in the TarP–3RboP complex, with key amino acids shown (cyan). Asp181 is highlighted in red. The ribitol of 3RboP is coloured green and D-ribitol-5-phosphate units 1, 2 and 3 (RboP1, RboP2, and RboP3) are labelled. Hydrogen bonds and salt bridges are shown as black dashed lines. b, Ternary complex of TarP with UDP-GlcNAc and 3RboP. UDP-GlcNAc, Mg2+ and 3RboP are shown as full-atom models coloured yellow, magenta, and green, respectively. c, View into the active site of TarP. C1 of UDP-GlcNAc and Asp181 are highlighted with red labels. The arrow indicates how the C3-hydroxyl in RboP3 could nucleophilically attack GlcNAc C1. d, Comparison of the polyRboP-binding site of TarP with the corresponding region in TarS. Residues of TarP and 3RboP are coloured as in a. TarS residues are coloured violet and the two sulfates are labelled S1 and S2. Only residues of TarP are labelled, for clarity. Key TarP and TarS residues lining the polyRboP-binding site are shown at the bottom, with three identical (red) and one conserved amino acids (blue). e, Superposition of UDP-GlcNAc-bound TarS with the ternary TarP–UDP-GlcNAc–3RboP complex. UDP-GlcNAc and 3RboP bound to TarP are coloured as in b, whereas UDP-GlcNAc bound to TarS is coloured in cyan. Only the TarS residues are shown (coloured as in d), for clarity. The arrows indicate the C1 positions of UDP-GlcNAc in TarP and TarS.


Some immunology effects:



The caption:

a, TarP expression reduces deposition of IgG from human serum on N315 cells. The protein A gene spa was deleted in all strains. Top, human IgG isolated from three individual healthy donors (A, B, and C; n = 4); bottom, left, IgG from human serum enriched for RN4220 WTA binding (n = 4); middle and right, pooled human IgG from different suppliers (Abcam, n = 4; Athens R&T, n = 6). Results were normalized against wild type and shown as means with s.d. of n experiments. P values for comparison with wild type were calculated by one-way ANOVA with Dunnett’s post-test (two-sided), and P ≤ 0.05 was considered significant. Significant P values are displayed. b, TarP reduces neutrophil phagocytosis of N315 strains lacking protein A, opsonized with indicated concentrations of IgG enriched for WTA binding. Values are depicted as mean fluorescence intensity (MFI). Means of two dependent replicates of a representative experiment are shown. The other two representative experiments can be found in Extended Data Fig. 1g. c, TarP abrogates IgG response of mice towards WTA. For each experiment, WTA from N315 ΔtarP or ΔtarS was isolated independently. At least three mice per group were vaccinated and analysed for specific IgG at indicated time points after vaccination. Results are depicted as mean absorbance with s.d. Individual mice are indicated by colour. Increase in IgG levels was assessed by one-way ANOVA with Tukey’s post-test (two-sided). Significant differences (P ≤ 0.05) are indicated with corresponding P values. d, Vaccination with WTA does not protect mice against tarP-expressing N315, as shown for bacterial loads in kidney upon intravenous infection. No significant differences between groups of either five vaccinated mice or four mice for the alum control group (means indicated), calculated by one-way ANOVA, were observed.


Some concluding remarks:

Protection against S. aureus infections is urgently needed, in particular for hospitalized and immunocompromised patients2,4. Antibodies can in principle protect against S. aureus, but their titres and specificities vary largely among humans and they are often not protective in immunocompromised patients3, probably in particular against S. aureus clones that mask dominant epitopes, for instance using TarP. Unfortunately, all previous human vaccination attempts with protein or glycopolymer antigens have failed, for reasons that are unclear24. Our study identifies a new strategy used by pandemic MRSA clones to subvert antibody-mediated immunity, which should be considered in future vaccination approaches. S. aureus WTA with GlcNAc at RboP C3 has been reported as a type-336 antigen, but was not further explored25. We found that tarP is present in type-336 S. aureus (Extended Data Fig. 1f). However, TarP-modified WTA is a very poor antigen and vaccines directed against GlcNAc at WTA RboP C3 or C4 may fail against many of the pandemic MRSA clones. The structural characterization of TarP will instruct the development of specific TarP inhibitors that could become important in combination with anti-WTA vaccines or antibiotic therapies...

...TarP is a new and probably crucial component of the S. aureus virulence factor arsenal26,27, highlighting the important roles of adaptive immunity and its evasion in S. aureus infections.


A note, which may or may not be all that easy to comprehend, from the front lines in confronting the growing antibiotic crisis with molecular biology.

Have a pleasant day tomorrow.

Pentavalent States Observed in Curium, Berkelium and Californium.

The paper I'll discuss in this post is this one: Pentavalent Curium, Berkelium, and Californium in Nitrate Complexes: Extending Actinide Chemistry and Oxidation States (Attila Kovács,*,† Phuong D. Dau,‡ Joaquim Marçalo,§ and John K. Gibson*, Inorg. Chem., 2018, 57 (15), pp 9453–9467.

The shape of the periodic table is actually a quantum mechanical effect. Every electron in an atom must have a unique set quantum configuration numbers, defined by it's primary shell number (which are represented by the rows in the periodic table), and then its suborbital, usually designated for historical reasons as s, p, d, and f, which are represented by its position in a column relative to the "steps" that appear in the table's shape.

In the periodic table both the lanthanides and actinides, the "f elements," appear in the boxes below the main group elements, and the discovery that the actinides, in particular, should go there was the recognition by Glenn Seaborg that they were "f elements" and not, as previously thought as "d elements" that begin with Scandium (Sc) and end with the synthetic element Copernicium (Cn), the "d block elements. The "d block" is actually broken by elements La-Lu (Lanthanum to Lutetium) and Ac-Lw (Actinium to Lawrencium). In fact the "f elements" should represent another "step" in the periodic table, but printing it in this way is logistically difficult since it would be difficult to print on standard paper without making the print too small to read, so they're put in boxes below the "main group" elements.

The heaviest element that has been isolated in a relatively pure form in quantities that are visible is element 99, Einsteinium. It seems theoretically possible to isolate, perhaps, albeit at enormous expense, a visible, if transitory, sample of fermium, element 100, since it is the last element formed by sequential beta decay, but I don't believe it has ever been done, nor will it ever be done. Generally fermium and all of the elements beyond are synthesized on an atom by atom scale in accelerators and are basically known from their decay products and the high energy radiation they produce.

The lanthanide elements, with a few important exceptions generally exhibit the +3 oxidation state, although a few elements like cerium (+4) and europium and samarium (+2) have other oxidation states, but they are all mostly characterized by +3 oxidation state, making their separations from one another somewhat difficult, meaning that their industrial chemistry, important in many modern devices, is at best environmentally suspect at best, environmentally odious at worst.

The chemistry of the lower actinide elements, including those that naturally occur if far richer. In fact thorium is almost always found in the +4 state, protactinium in the +5 state, and uranium in either the +4 or +6 state in the natural environment. For a long time, before Seaborg's discovery, these elements were thought to be "d elements" and in fact, thorium has chemistry much closer to zirconium and hafnium than say, curium, protactinium is more "tantalum like" than curium like, and uranium has many similarities to tungsten. (The presence of billion ton quantities of uranium in oceans only became possible on earth after oxygen appeared in the atmosphere, resulting in the somewhat more soluble +6 uranium oxidation state being formed by oxidation as opposed to the very insoluble +4 state. Uranium, and plutonium, but not generally neptunium, have well characterized +3 states, but thorium, protactinium, do not. (Uranium, neptunium, and plutonium all exhibit volatile hexafluorides (+6) albeit of decreasing stability in sequence; a fact of industrial importance; in the oceans and in certain fresh water supplies, uranium VI is present as the dioxo ion.)

In nuclear technology, the existence of multiple oxidation states among actinide elements greatly simplifies their separations from one another (but not necessarily from fission products), at least in the case where there are only trivial amounts of the transamericium elements, curium and berkelium and californium, all of which can be isolated in gram quantities, and in a the case of curium, kg quantities.

I personally always assumed that except for some exotic chemistry involving +2 states for curium at least, that curium, berkelium and californium most commonly exhibited +3 chemistry and that no higher states existed.

I was wrong.

From the paper cited above:

The range of accessible oxidation states (OSs) of an element is fundamental to its chemistry. In particular, high OSs provide an assessment of the propensity, and ultimately the ability, of valence electrons to become engaged in chemical bonding. Until recently, the highest known OS in the entire Periodic Table was VIII, such as in the stable and volatile molecules RuO4 and OsO4. The OS IX was finally realized in the gas-phase complex IrO4+,(1) but neither this moiety nor this highest OS has been isolated in the condensed phase.(1,2) The appearance of distinctive and otherwise inaccessible chemistry in gas-phase species, such as IrIX in IrO4+, is generally attributed to isolation of a moiety that would otherwise be highly reactive with neighbor species in condensed phases.(3) For example, gas-phase PaO22+, which comprises formally PaVI, has been synthesized, but it activates even dihydrogen to yield atomic H and PaO(OH)22+ in which the stable discrete PaV OS state is recovered.(4) In view of its gas-phase reactivity, there is scant chance of isolating PaO22+ in the condensed phase. Another example of a distinctively high OS accessible (so far) only in the gas phase is PrV in PrO2+ and NPrO,(5,6) this being the only known pentavalent lanthanide.

The early actinides yield ultimate OSs, from AcIII to NpVII, that correspond to engagement of all valence electrons in chemical bonding to yield an empty 5f0 valence electron shell.(7) After Np, the highest accessible actinide OSs, from PuVII to lower OSs beyond Pu, have one or more chemically unengaged valence 5f electron(s), as the nuclear charge increases and energies of the 5f orbitals decrease. The transition from chemical participation of all 5f valence electrons in ubiquitous UVI, to participation of only two valence electrons in prevalent NoII,(8) distinguishes the actinides from the lanthanides for which the relatively low energy of the valence 4f orbitals results in only a few OSs above trivalent.(9) The gas-phase molecular ions BkO2+ and CfO2+ were recently synthesized and their OSs computed as BkV and CfV, which was an advancement beyond oxidation state IV for these elements and extended the distinctive actinyl(V) dioxo moieties into the second half of the actinide series.(10) It is notable that the computed oxidation state in ground-state CmO2+ is not CmV but rather CmIII, which reflects the limited stabilities of OSs above III for the actinides after Am.(10)

A primary goal of the work reported here is to assess stabilities of OSs, particularly the pentavalent OS, of the actinides Cm, Bk, and Cf. These elements represent the transition from the early actinides that exhibit higher OS, including AmVI and possibly also AmVII,(11) to the latest actinides, Es through Lr, that have been definitively identified only in the AnII and/or AnIII OS. The meagre realm of OSs for the late actinides may not be entirely due to intrinsic chemistry because synthetic efforts for these elements have been very limited due to scarcity and short half-lives of available synthetic isotopes. Cm, Bk, and Cf are the heaviest actinides available as isotopes that are both sufficiently abundant (>10 μg) and long-lived (>100 days) for application of some conventional experimental approaches with relatively moderate procedural modifications.


The higher oxidation states were synthesized in the gas phase by the use of electrospray ionization (ESI) and detected in the mass spectrometer in which the ESI was performed.

The results of the spectra were verified by quantum mechanical computations using AIMAll Software

Some cool pictures from the paper:



The caption:

Scheme 1. Generic D2h, C2v, and C2 Symmetry Structures for AnO2(NO3)2–


Apparently this technique has also been applied to lanthanides, motivating this work:




Figure 1. CID mass spectra acquired at a nominal instrumental voltage of 0.5 V for (a) Ce(NO3)4–, (b) Pr(NO3)4–, (c) Nd(NO3)4–, and (d) Tb(NO3)4–. Elimination of NO2 is indicated by arrows. Sequential CID elimination of two NO2 is observed only for Pr(NO3)4– to yield PrO2(NO3)2–.


Mass spectra from the actinides:



The caption:

Figure 2. CID mass spectra acquired at a nominal instrumental voltage of 0.5 V for (a) Pu(NO3)4–, (b) Am(NO3)4–, (c) Cm(NO3)4–, (d) Bk(NO3)4– (with 7% isobaric Cf(NO3)4– from beta-decay of 249Bk), and (e) Cf(NO3)4–. Elimination of NO2 is indicated by arrows. Sequential CID elimination of two NO2 molecules from An(NO3)4– to yield AnO2(NO3)2– is observed in all five cases.


Some calculated structures:



The caption:

Figure 3. Structures of CfIVO2(NO3)2– (top) and CfIIIO2(NO3)2– (bottom) in two perspectives and selected distances in angstrom from CASPT2/DZ calculations.


Results of density functional theory calculations for a curium oxonitride complex:



The caption:

Figure 4. Electron density map of CmO2(NO3)2– from DFT calculations. Charge concentration is indicated by yellow, while charge depletion is indicated by blue.


Molecular orbitals for the plutonium complex in this class:



The caption:

Figure 5. Characteristic molecular orbitals of PuO2(NO3)2– from CASPT2 calculations


The same thing for Berkelium:



The caption:

Figure 6. Characteristic molecular orbitals of BkO2(NO3)2– from CASPT2 calculations.




A text excerpt:

Of the various theoretical approaches, only the AIM model can characterize quantitatively the space between the bonding atoms. Therefore, we performed a topological analysis of the electron density distribution of the AnVO2(NO3)2– complexes in order to see how the density properties of the An–O bonds vary along the 5f row. We were particularly interested in the parameters of An–nitrate interactions, as they may provide a clue on the increasing bend along the actinide row. A graphical representation of the bonding paths, bond and ring critical points of AmVO2(NO3)2– is shown in Figure 7.


Figure 7:



The caption:

Figure 7. Bonding paths (black), bond (green), and ring (small red) critical points of AmVO2(NO3)2–.


Ionization energies:




The caption:

Figure 10. Actinide ionization energies in eV(79) (using corrected value for IE[U3+] as discussed above): (a) fourth IE; (b) fifth IE; (c) sum of fourth and fifth IEs. Dotted lines are approximate upper stability boundaries for (a) AnIV relative to AnIII; (b) AnV relative to AnIV; (c) AnV relative to AnIII.


Some remarks from the conclusion:

Comparison of experimental results for lanthanide and actinide oxide nitrate anion complexes suggested the AnV oxidation state as coordinated actinyl(V) moieties embedded in AnO2(NO3)2– for An = Pu, Am, Cm, Bk, and Cf, this being the first Cm(V) complex. The stability of oxidation state V in these AnO2(NO3)2– complexes has been confirmed by quantum chemical calculations. The relative stability of this oxidation state is particularly notable for Cf and Bk complexes, and therefore the AnIVO2(NO3)2– and AnIIIO2(NO3)2– forms have been explored and their lower stabilities with respect to CfV and BkV have been supported by both CASPT2 and DFT calculations. Whereas pentavalent Cf was expected to be stable due to a half-filled 5f7 configuration, the computations show that this configuration for CfVO2(NO3)2– is not octet with all seven 5f electrons spin-unpaired, but rather sextet with two of the 5f electrons spin-paired in a 5f1+ orbital.

The AnO2(NO3)2– complexes show interesting bonding features. While in the actinyl moiety the ionic character of bonding increases from Pu to Cf (in agreement with experience on several other actinide systems), in the An–NO3– interaction an opposite trend has been observed here. The increasing ionicity in the AnO2 moiety results in charge depletion around An making it more suitable as acceptor for charge transfer from the nitrate oxygens. The increasing covalent character from Pu to Bk ≈ Cf may be an important factor for the trend observed in the molecular geometries, i.e., a gradual bend of the NO3– ligands (described by the N–An–N angle) around An...


I'm well aware that this may all seem very "out there," and perhaps, in some quarters, generate remarks along the lines of "I couldn't care less."

I assure you though, whether you are inclined to believe it or not, or even if you despise the idea, that the chemistry of the actinides is critical, absolutely critical, to saving whatever is left to save of our rapidly deteriorating environment.

I wish you a rather pleasant Sunday.

Nobel Laureate and Nagasaki Atomic Bomb Survivor Osamu Himomura Has Died.

From Nature: Osamu Shimomura (1928–2018)

Growing up during one of the darkest times in history, Osamu Shimomura devoted his long and fruitful career to understanding how creatures emit light. He discovered green fluorescent protein (GFP), with which — decades later — biomedical researchers began to monitor the workings of proteins in living tissue, and to confirm the insertion of genes. For that discovery, he shared the Nobel Prize in Chemistry in 2008 with neurobiologist Martin Chalfie and the late Roger Tsien, a chemist.

Shimomura, who died in Nagasaki, Japan, on 19 October, was the first to show that a protein could contain the light-emitting apparatus within its own peptide chain, rather than interacting with a separate light-emitting compound. The significance of this discovery was that the gene encoding GFP could, in principle, be copied (or ‘cloned’) and used as a tool in other organisms...

...Born on 27 August 1928 in the town of Fukuchiyama, at the height of Japanese expansionism, Shimomura was the son of an army captain whose frequent postings abroad disrupted his child’s school education. Shimomura’s grandmother instilled in him the samurai principles of honour and fortitude. In 1944, with the Pacific War turning against Japan, he and his fellow school students were mobilized to work in a munitions factory in Isahaya, about 25 kilometres from Nagasaki. On 9 August 1945, he was at work when a blinding flash, followed by a huge pressure wave, signalled the dropping of the atomic bomb on the nearby city. He walked home under a shower of black rain. He later wrote that his grandmother’s quick action in putting him straight in the bath might have saved him from the effects of the radiation.

Without a high-school diploma, he despaired of finding a college place. Eventually, Nagasaki Pharmacy College admitted him in 1948. On graduation, he worked for four years as an assistant in practical classes. He devised research projects in his own time, and his professor obtained permission for him to do a year of advanced study...

...The luciferin paper brought an invitation for Shimomura to join the bioluminescence lab of biologist Frank Johnson at Princeton University in New Jersey. Three weeks after marrying Akemi Okubo in August 1960, Shimomura sailed to the United States, his travel paid for by a Fulbright scholarship...

...He discovered almost at once that it was activated by calcium (later, aequorin became an essential reagent as a glowing marker of calcium release). Shimomura, his family and his research colleagues spent 19 summers at Friday Harbor, collecting hundreds of thousands of jellyfish to obtain enough of the elusive material for a full structural analysis. Until a way of making genetically engineered aequorin became available in the 1990s, Shimomura freely shared his carefully harvested stocks with laboratories the world over...


Remarkable.

He reminds me of another Japanese scientist who labored in obscurity on a difficult project, investing heavily his own time, Shuji Nakamura (now at UC Santa Barbara).

One of my son's professors got his Ph.D. and did a post doc with Nakamura.

Nature Editorial for Scientists: Beware the rise of the radical right

The following editorial appears in the journal Nature, one of the world's premier scientific journals:

Beware the rise of the radical right

Academic freedom is on the hit list when radical politicians gain office — as they have done in Europe.

Some excerpts:

Hidden inside a 1970s office block close to London’s Waterloo station is a tiny organization that has helped tens of thousands of academics find sanctuary from conflict. Co-founded 85 years ago by the economist William Beveridge and physicist Ernest Rutherford, the organization, now called the Council for At-Risk Academics (CARA), enabled many notable twentieth-century scientists — including biochemist Hans Krebs and philosopher Karl Popper — escape the Nazis and settle at British universities. In recent years it has reached out to the Middle East and receives the largest volume of applications from Yemen and Iraq.

CARA and its counterparts in other countries exist because governments in the host nations value three of the pillars on which democracy rests: the rule of law, a free press and, as we explore in a Comment article, freedom of academic enquiry. If the British government were to decide not to support even one of these, CARA would struggle to carry on...

...Europe’s heads of government are biting their lips, and their reasons for doing so are understandable, even if European agreements or conventions are being violated. There is, of course, the principle of non-interference in the affairs of a sovereign state. But, in addition, the EU works through the collective solidarity of its member states. This is what has enabled the organization to enact progressive policies in climate change, anti-discrimination legislation and employee rights.

But collective progressivism breaks down when one-third of EU governments include political parties with scant commitment to protecting democratic institutions. Now that EU governments include parties who do not believe in the rights of people from minority groups, the consensus on climate change, or, indeed, academic freedom, it will become more difficult for the EU as a whole to either advance, advocate or protect policies in these fields...


I don't know why the editorial singles out Europe.

The United States - and now Brazil - are ruled by some of the worst examples of human beings the world has ever seen.

We will see if "the rule of law" can survive in the US. How history will regard it will depend entirely on whether the orange nightmare and his enablers see prison time or, better yet, die in prison.

The implications extend well beyond science, but at as we are realizing the climate catastrophe predicted years ago by scientists, more than science is at risk. It is the very future of humanity that is on the line.

Technetium in Use and in the Environment: Alloys, Sellafield Lobsters and Deep Eutectic Solvents.

The paper, among others, that I will discuss in this post is this one: Efficient and Selective Extraction of 99mTcO4– from Aqueous Media Using Hydrophobic Deep Eutectic Solvents (Tim E. Phelps , Nakara Bhawawet , Silvia S. Jurisson* , and Gary A. Baker,* ACS Sustainable Chem. Eng., 2018, 6 (11), pp 13656–13661)

In my late teens, I had a weekend job in a hospital pharmacy working on the distribution of IV solutions to the different hospital wings. The room in which I worked was not actually in the pharmacy, but was rather attached to the Central Supply room which was also staffed by two other teenagers, two young women - leading to all sorts of flirting but no real romance - one of whom was the niece of a prominent physician on the Hospital staff. Because of her uncle, she knew many of the doctors who worked in the hospital, including, as luck would have it, the pathologist who conducted autopsies. The pathologist, a Nisei, was an avuncular guy, and because of the connection with her uncle, that young woman was able to weasel invitations for the three of us to go to autopsies, perhaps because the pathologist was trying to stimulate interest among us kids to go into medicine or at least learn something about anatomy.

As a result, I got to watch maybe 10 or so autopsies after finishing my IV distribution work, and although I had no interest whatsoever of going into medicine, I certainly got some insight into at least one human disease, lung cancer, a disease which would later kill my father. I recall the autopsy of the lung cancer victim very well, probably much better than all the other autopsies I attended, with the possible exception of a still born baby with a three chambered heart. The pathologist was going through the lungs of the lung cancer victim and for our benefit, removed a tumor and sliced it in half to show us something very interesting, which was that at the very center of the tumor there were black particles, carbon I'd guess. Since I was worried all the time about my father - a heavy smoker who would nevertheless go on to live 20 years after these adventures of mine - I asked the pathologist if the dead man had been a smoker. "No," he replied, "smoker's lungs look much, much worse than this. This man was a teacher in New York City. This is from air pollution."

I never forgot that moment. On reflection, I think it changed my life. Thank you Dr. Araki.

Recently in this space, in an exchange with a dumb anti-nuke, if I recall correctly, I mused about the to which the idea that dangerous fossil fuels are cheap and affordable and even essential - and thus that we cannot live without them - is connected to the undeniable fact that they are routinely, without a peep, allowed to do what the nuclear industry is not allowed to do, which is to directly dump its waste products directly into the environment.

The distinction here is connected with something about which I often rail uselessly, the difference between internal and external costs. The internal cost of the dangerous fossil fuel gasoline is what you pay at the pump or at the outlet. The external cost is the cost (among others) of the people who die – often horribly, sometimes after long periods of disability - from the air pollution the combustion of your gasoline, never mind coal and gas for electricity, produces.

By contrast, the nuclear industry is held to a standard which essentially demands that no one ever be hurt or injured, much less killed by it’s by products – most commonly referred to as “nuclear waste,” although I personally don’t use that term since I insist that anything that is useful need not be “waste.”

As it happens though, the nuclear industry has deliberately released radioactive fission products in the past, most notably at the La Hague and Sellafield nuclear fuel reprocessing plants, one of which is now shut, albeit at an overall loss to humanity. The health consequences resulting from this practice would be negligible were it not for the pollution generated by people powering up their computers effectively to complain vociferously about how tragic it is that any radioactive atom exists anywhere; generally these are the same people who couldn’t care less about the 7 million people who die every year from air pollution and the fact that there are no living things on this planet that are not exposed to essentially all of the many toxic constituents of dangerous fossil fuel waste in addition to carbon dioxide.

Of course, one might argue that there are no living things on the planet which have not been exposed to fission products, for example, technetium in the form of the highly water soluble and therefore highly mobile pertechnate ion, TcO4-. This, by the way, is true. It is also true that people deliberately eat or are injected with the pertechnate ion in hopes of saving their lives, but that’s another matter on which I’ll touch below.

The processing plants at Sellafield utilize(d) the PUREX process for isolating plutonium from used nuclear fuel. This is a solvent extraction process wherein fuel rods are chopped and then largely dissolved in nitric acid. A series of solvent extractions, coupled with precise oxidation and reduction steps allow for separation of the various elements constituting fission products and actinides by selectively putting some of them in a form that makes them hydrophobic ,so that they can be extracted into the dangerous fossil fuel product kerosene containing complexing agents, the most famous of which is tributyl phosphate, although many similar complexing agents tailored for very specific target elements, for example, americium, neptunium and curium are known.

In these extractions, most of the fission products, except the precious metal fission products, ruthenium, rhodium and palladium as well as the gaseous fission products – largely krypton and xenon along with some decay generated helium-4 and sometimes small amounts of hydrogen containing three isotopes including the radioactive isotope tritium and its decay product helium-3, – remain in the acid solution. Notable constituents of this solution are the relatively long lived radioactive isotopes of cesium, iodine – chiefly iodine-129 – strontium and the aforementioned pertechnate ion.

Historically, these aqueous solutions have been problematic, and people didn’t know exactly what to do with them. At the Hanford Site in Washington State, where during the era of cold war hysteria, huge amounts of plutonium was isolated in order to manufacture nuclear weapons - these solutions were simply placed in giant tanks. The first tanks so utilized were single shell tanks from which they ultimately leaked, causing a great deal of concern and the expenditure of huge amounts of money to clean them up. The Hanford tanks are a giant bugaboo for those interesting people who freak out every time radioactivity is mentioned without even the slightest consideration of relative risk. Of course, there is no evidence that the nearby city of Richland, Washington is at risk of being depopulated by these tank leaks; there may be some elevated but as yet undiagnosed risks there; I can’t say. Perhaps the increased level risk of living in Richland is roughly comparable to the risk might approximate the risk of commuting in one’s automobile 50 miles per day instead of walking to work around the corner. Again, I can’t say, but it seems clear to me that the risks are overstated – often vastly overstated - when nuclear materials are discussed, and largely ignored when dangerous fossil fuel materials are discussed.

For a favorite example in my own discourse, one of the most stupid remarks I’ve encountered in this space came from a correspondent, now on my “ignore list,” who announced that the collapse of a tunnel containing some old chemical reaction vessels at the Hanford site “proved” that nuclear energy was “dangerous,” – even if there is zero evidence that anyone died or will die as a result of this event. Of course, the correspondent, from what I could tell, was completely disinterested in the possibility that 70 million deaths every decade, without stop, from air pollution might have some bearing on the related question of whether fossil fuels are “dangerous.” (I routinely claim that they are just that, dangerous fossil fuels, and seldom refer to fossil fuels in any other way.)

In Britain, the equivalent of the Hanford Site is the Sellafield Site on the coast of England, in Cumbria, which borders Scotland. It is the site of the world’s first commercial scale nuclear power plant,– the Russians had built a smaller plant that they connected to the grid a bit earlier – the Calder Hall reactor, which operated from 1956 to 2003, using rather (understandably) primitive technology.

Truth (an unpopular commodity) be told, though, the “primitive technology,” the carbon dioxide working fluid might prove quite interesting in the case that humanity actually got serious about climate change – there is no evidence this will actually happen – since the key to the thermochemical splitting of carbon dioxide is, as it sounds, hot (supercritical) carbon dioxide. This suggests that one could imagine a working fluid that is a continuously shifting mixture ratio of two carbon oxides, dioxide and monoxide, with periodic separations of the two, one providing carbon for use, the other turning turbines to drastically increase thermodynamic efficiency and generating some pure oxygen on the side, which also might be useful for industrial scale carbon capture from the air.

The Calder Hall Reactor was deliberately designed to be a type of reactor that made access to weapons grade plutonium possible. Obtaining weapons grade plutonium is economically wasteful, since it requires relatively short irradiation times and low burn up in order to prevent the buildup of Pu240, which greatly complicates weapons manufacture as well as reducing the yield of weapons know colloquially as “fizzle.”

“Burn up” in a nuclear reactor may be thought of as fuel efficiency, translating “miles per gallon” into “megawatt-days per ton.” The growth in US (and other countries’) nuclear power production in the 1990’s – which lead to it having the highest capacity utilization of any type of electrical generation plant - despite the disastrous US policy of abandoning nuclear plant construction infrastructure, is, along with operating experience, a function of increased burn-up, since it reduces the number of days required for refueling shut downs. The longer the burn up time utilized in a reactor at maximum power levels, the more useless the plutonium generated in them becomes for weapons manufacture. For “breed and burn” types of reactors, accumulation of Pu238 (from the buildup and decay of Cm242) makes the use of all of the plutonium completely unusable for weapons. (Cf. A new scientific solution for preventing the misuse of reactor-grade plutonium as nuclear explosive (Kessler et al, Nuclear Engineering and Design 238 (2008) 3429–3444).)

Let’s be clear as an aside: The British nuclear weapons program utilized Calder Hall weapons grade plutonium (as well as Windscale Plutonium) to make nuclear weapons. Their nuclear weapon inventory is nowhere near the scale of either the Russian or American inventory, but the recent demonstration that even in a formerly stable democracy, the control of nuclear weapons can fall into the hands of patently insane people – the existence and position of the clearly insane person Donald Trump shows that the representation of Jack T. Ripper in “Dr. Strangelove” was, and now is, not as much comedy as designed – obviates the fact that nuclear weapons must be eliminated and that no country can be trusted to possess them.

The reprocessing of used nuclear fuel for the purpose of making bomb grade plutonium with the PUREX process requires the use of far more solvents and reagents than reprocessing commercial nuclear fuel because the plutonium contained in the fuel is far more dilute. Although ultimately the British switched to the less onerous processing of commercial fuels, almost all of the initial reprocessing performed at Sellafield was for fuels being used to make weapons.

The British utilized a different approach to dealing with the aqueous raffinates containing fission products (and small residual amounts of actinides) than the American did at Hanford and the Soviets did at Mayak. After some processing, they, having a coastal plant as opposed to inland plants like Mayak and Hanford, dumped many of the fission products, along with actinide residues including plutonium, in the ocean utilizing an outfall pipe extending a few kilometers into the Irish Sea. (British Magnox fuels which were designed for simplified reprocessing, unlike American, French, and most other nations' nuclear fuel, must be reprocessed; they are not suitable for long term storage.)

For the rest of this post, I will focus on one radioactive component of this raffinate, technetium.

Technetium, which has the chemical symbol Tc, is the 43rd element in the periodic table. All of its known isotopes are radioactive. One isotope – one that is actually quite difficult to obtain – 98Tc, has a half-life of 4.2 million years, still far too short to have survived the 4.5 billion years since the accretion of the earth from the supernovae ejecta from which it formed. It is unlikely that there is even 100 grams of it on the entire planet. Any that exists has been manufactured by humanity at great expense in accelerators, or obtained in nuclear reactors at miniscule yields. The better known and more readily available isotope is 99Tc which is a major fission product when an actinide element such as uranium or plutonium, americium or curium undergoes a fission event, either spontaneously or as a result of being struck by a neutron as in a nuclear reactor. It is generally regarded as a “synthetic element,” and was, in fact, the first such element to be discovered, in 1937. That said, because uranium is a relatively common element in the earth’s crust, as common as tin, and because uranium has continuously been undergoing spontaneous fission since the formation of the earth, it is now understood that technetium does occur naturally, albeit in concentrations that are so low that it makes its detection exceedingly difficult and its isolation from natural sources nearly impossible.

The Earth’s oceans, for instance, contain – limited only by uranium’s marginal solubility in water – about 5 billion tons of uranium. The half-life of uranium’s most common isotope, 238U, is 4.468 billion years, coincidentally nearly equal to the age of the earth. The nuclear decay of uranium – which like technetium only has radioactive isotopes – usually decays by α emission, but far more rarely it also undergoes spontaneous fission. The spontaneous fission half life of Uranium-238, as opposed to its much shorter α decay half-life, is about 8 quadrillion years, meaning that the decay constant (=ln(2)/t½) for spontaneous fission is 2.8 X 10-24 sec^(-1). From this information, one can calculate that about 30 trillion atoms of uranium fission each second in Earth’s oceans. The fission yield of lighter isotopes for uranium-238’s spontaneous fission is given at the JENDL website and can be found by summing the fission yields of the predominant species with mass number 99 formed directly by fission, 99Rb, 99Sr, 99Y, 99Zr, 99Nb, and 99Mo, each one upon formation decaying by β- decay into the following member of the decay series. The sum of these yields suggests that 6.154% of the time, a nucleus with mass number 99 is formed under these circumstances. With the exception of 99Mo, which has a half-life of about 64 hours, none of these highly radioactive isotopes has a half-life exceeding 2 minutes, and all of them rapidly decay ultimately to give 99Tc which has a half-life of 211,100 years. Thus 99Tc represents a “decay bottleneck,” if you will, before itself decaying into the stable ruthenium isotope 99Ru. From the decay constant of 99Tc, which is 1.04 X 10-13 sec-1, one can calculate that the steady state quantity of 99Tc – the amount of 99Tc that can accumulate before it decays at exactly the same rate at which it is formed – in earth’s oceans arising from the natural spontaneous decay of solvated uranium is about 3.4 kilograms, distributed in all the oceans in all the world.

The amount of technetium released at Sellafield absolutely dwarfs the amount of naturally occurring technetium in the ocean. It is estimated that the total cumulative amount of technetium as of 2006 was 1700 terabequerels. (cf. An estimate of the inventory of technetium-99 in the sub-tidal sediments of the Irish Sea (Leonard et al Journal of Environmental Radioactivity 133 (2014) 40-47).) The specific activity of technetium is 0.63355 gigabequerels per gram, meaning that the total cumulative amount of technetium released into the Irish Sea was on the order of 2.7 metric tons. Although technetium PUREX raffinates all contain technetium in the +7 oxidation state, again, as the highly soluble pertechnate ion, TcO4-, it is well known from nuclear testing, nuclear accidents, and sewage treatment plants containing technetium from the urine of patients injected with the element for imaging purposes, that the pertechnate ion can be reduced by organic matter or by organisms to the insoluble oxide in the +4 state, TcO2, technetium dioxide. The paper just cited indicates that about 2% of the Sellafield releases are found in sediments in the Irish Sea, undoubtedly largely in this form.


The quantities of technetium released at Sellafield varied from year to year and exhibited large peaks and valleys. A paper on the subject of technetium releases and incorporation of the element into the edible tissues of local lobsters and crabs reports that technetium releases peaked around 1995 after a new plant, most probably using a new variant of the PUREX process, called the EARP (Enhanced Actinide Recovery Plant) went into operation in 1994. (cf. Variability in the edible fraction content of 60Co, 99Tc, 110mAg, 137Cs and 241Am between individual crabs and lobsters from Sellafield (north eastern Irish Sea) (D.J. Swift, M.D. Nicholson, Journal of Environmental Radioactivity 54 (2001) 311-326). According to this paper, the Sellafield Tc releases rose from about 5 Terabequerels on average in preceding years to 72 TBeq (114 kg), 192 TBeq (303 kg), 155 TBeq (245 kg), 84 TBeq (133 kg), and 53 TBeq (84 kg).

The authors of this paper purchased crabs and lobsters from local fishermen who were known to be obtaining their catches near the Sellafield outfall pipe on May 25, and June 5, of 1997.

The number of crabs collected was 34, with 16 females and 18 males being collected. The mean weight of the crabs was 490 grams, and the mean weight edible tissues was 148 grams.

For lobsters, 37 were collected, 20 females and 17 males. The mean weight of these animals was 654 grams - 523 grams for females, 807 grams per male, with the edible portions of each, respectively, being 160 grams and 246 grams.

In this paper, the naturally occurring radioactive isotope K-40 that is present in all of the essential element potassium on the Earth is measured as a marker for all of the other radioisotopes measured in the experiment, Ag-110m, Cs-137, Am-241, Co-60 as well as Tc-99. In crabs, the only radisotope found to be at the same order of maginitude as postassium-40 is technetium; all the others are found at an order of magnitude lower. The mean measurement for potassium-40 is 93 Beq/kg, and 126 Beq/kg for crabs, with a rather large standard deviation which is on the order of the measurement itself. The other radioisotopes are found at levels approaching their lower limit of detection, an order of magnitude smaller than potassium-40.

For lobsters, the situation is quite different.

Lobsters seem to concentrate technetium. The mean value for lobsters is 11,300 Beq/kg, reflecting 7,131 Beq/kg for male lobsters and 14,853 Beq/kg. The mean mass of edible meat of female lobsters in this sample was 160 grams, meaning that if one ate an “average” female lobster that lived its life near the Sellafield outfall pipe in the spring of 1997, one would end up eating 2,377 Beq of Technetium, without reference to the experimental error discussed at length in this paper.

I plainly confess that for about 1/3 of my adult life, I was an anti-nuke, sometimes rabid, sometimes passive, and as such, was completely divorced from critical thinking about nuclear issues and in fact I knew nothing at all, effectively, about nuclear science but nonetheless felt myself qualified occasionally to be outraged by the existence of things like the Sellafield plant. I can easily therefore imagine how a person dumb enough to say, think that the collapse of a tunnel holding old radiologically contaminated chemical vessels at Hanford suggests that nuclear power is “dangerous” on a planet where 7 million people die every year from air pollution, might view the idea of 2,377 Beq of technetium in the meat of a lobster growing up near the outfall pipe of the Sellafield nuclear reprocessing plant. One can be quite sure as well that the ship of fools belonging to that benighted organization Greenpeace, the Rainbow Warrior, cruised all around the North Sea burning diesel fuel carrying functional idiots flashing signs and banners with inane content all because of Sellafield.

The means of detection of technetium in lobster meat says nothing at all about the chemical speciation of the technetium in it, whether it is present as soluble pertechnate – which apparently behaves much like iodine biochemically – or as insoluble technetium dioxide. In the latter case, it’s not clear that any technetium ate by a lobster lover would be bioavailable and thus absorbed into the blood stream of the feasting person. But let’s consider opposite case, the pertechnate case, and assume really without any justification that all of the technetium found in a consumed female lobster is absorbed by the person eating the lobster. The biological half-life of technetium, the rate at which it is excreted, or put in cruder terms, pissed away, is well known because of its extreme technological importance in medical imagining and in cancer treatment. It is about 1 day. The reason it is so well known is that about 20 million people per year are deliberately injected with solutions containing technetium complexes. The reason this is so is not for the purpose of comparing them to Sellafield lobsters of course, but is rather intended to save their lives, or perhaps just to improve them dramatically. The technetium so injected is far more radioactive than Sellafield technetium, since it is largely a nuclear isomer of technetium-99, technetium-99m, which decays via an isomeric transition with the release of a gamma ray into the same technetium-99 at the outfall pipes of Sellafield. The radiological half-life of the decay of Tc-99m into Tc-99 is about 6 hours, and it is obtained from shipments of its parent nuclide, Mo-99, with a half life of 64 hours, prepared in research reactors.

According to the Wikipedia page for Technetium-99m, the radiological dose that is typical of at least one procedure, a bone scan, ranges from 700 million Beq to 1,110 million Beq, which the reader is invited to compare with eating a female Sellafield lobster, which would provide a dose that is 2 to 3 orders of magnitude smaller assuming complete absorption of all of the technetium the animal contains. Please note that the number of people who have eaten such lobsters is vanishingly small.

The conceit of anti-nukes who actually regard Greenpeace as an environmental organization, egged on in this belief by a credulous scientifically illiterate news media, as opposed to how I regard them, as an organization roughly comparable to an organization of anti-vaxxers, or creationists (at best), is that if one eats even one radioactive atom that has found its way into the environment as a result of the operations of nuclear energy related plants, tragedy will inevitably result.

This is a Trumpian scale misrepresentation of reality, in other words, a bald faced lie. The toxicology of any agent of environmental insult is inherently statistical. It is simply not true, for example, that everyone who is exposed to air pollution will die from it. Statistical analysis suggest that 7 million people die each year from it, but billions of people who have been exposed to it will die from something else, like say automobile accidents, gun fire, excess consumption of fried foods, malnutrition, etc, "the thousand natural shocks that flesh is heir to."

I opened this long post with a description of the dissection of lung tissue that so obviated the relationship between air pollution and fatal disease that even a teenaged kid could discern the relationship visually. No such relationship between eating lobsters captured near the outfall pipes of the Sellafield Nuclear reprocessing facility is likely to exist, and if there are any people on this planet whose cancers developed from technetium released at either Sellafield or La Hague, there is simply no way that they exceed the cancers and deaths that would have resulted if the Magnox fuel had never existed, if Britain continued to rely on coal as it did at the time that the Calder Hall reactor was built.

To wit:

One of the best evocations of critical thinking about nuclear energy was written by the late Nobel Laureate (and Stanford Professor of Physics) Burton Richter, commenting on the paper written by the anti-nuke fellow Stanford Professor Mark Z. Jacobson, who I personally regard as a useless idiot. Writing in a comment in the journal Energy and Environmental Science, Richter wrote:

What struck me first on reading the Ten Hoeve–Jacobson (T–J) paper was how small the consequences of the radiation release from the Fukushima reactor accident are projected to be compared to the devastation wrought by the giant earthquake and tsunami that struck Japan on March 11, 2011. The quake and tsunami left 20 000 people dead, over a million buildings damaged and a huge number of homeless. This paper concludes that there will eventually be a 15-130-1100 fatalities (130 is the mean value and the other numbers are upper and lower bounds) from the radiation released from reactor failures in what is regarded as the second worst nuclear accident in the history of nuclear power. It made me wonder what the consequences might have been had Japan never used any nuclear power. My rough analysis finds that health effects, including mortality, would have been much worse with fossil fuel used to generate the same amount of electricity as was nuclear generated. This conclusion will surely draw fire since it flies in the face of what many believe, and of new policy directions some propose for Japan and Germany.


For context, in December of 1952, a few years before Calder Hall went on line, about 4000 people died as a result of a serious coal pollution event, the London Smog event, resulting from cold temperatures and low wind speeds.

(cf. Richter, Opinion on “Worldwide health effects of the Fukushima Daiichi nuclear accident” by J. E. Ten Hoeve and M. Z. Jacobson, Energy Environ. Sci., 2012,, Energy Environ. Sci., 2012, 5, 8758.

The essence of the paper is that nuclear energy need not be completely free of risk in order to save lives on balance.

Balance.

From all of the above, a fair assessment of what I have written would suggest that I am perfectly OK with people dumping technetium in the ocean. This, however, is not true.

Rhenium, the cogener of technetium is a very rare, but very valuable strategic metal, the chief use of which is as an alloying agent to make “superalloys” – alloys displaying remarkable chemical resistance and structural integrity at high temperatures. Because of the lanthanide contraction, the atomic radii of technetium and rhenium are quite nearly identical, and thus the alloy properties are very similar. Rhenium is subject to depletion, and, since the world supply of uranium can be shown to be effectively infinite, it is quite possible that the world supply of technetium might well be made to outstrip the supply of rhenium, and alloy for its use in closed systems such as high temperature turbines used in combined cycle power plants, almost all of which in existence today are dangerous natural gas plants, although it is quite possible to imagine cleaner and safer nuclear plants that would utilize this same combined cycle approach to improving thermodynamic efficiency.

There are only small differences between the chemistry and metallurgy of rhenium and technetium, these differences resulting from the shielding by filled f orbitals in rhenium that are not present in technetium. The melting point of rhenium (3186 C) is higher than technetium (2157 C) and rhenium forms a volatile heptafluoride whereas technetium does not form a heptafluoride at all. Otherwise the two elements are nearly identical.

Prevented from growing as much as it would in a sane world by appeals to fear and ignorance delivered by Greenpeace types, nuclear energy has been stuck at providing consistently about 28 exajoules for more than 3 decades. While this is nearly three times as much as the combined solar, wind, geothermal and tidal so called “renewable energy” schemes have managed despite nearly half a century of mindless cheering, it is clearly not enough, since the use of dangerous fossil fuels is rising, not falling, this as the obvious dire effects of climate change are becoming more obvious, and as the accumulation of the dangerous fossil fuel waste carbon dioxide is rising at the fastest rate ever observed.

An estimate of the total accumulated technetium available in used nuclear fuels has been made and is available here:
Determination of technetium-99 in environmental samples: A review (Hou et al Analytica Chimica Acta 709 (2012) 1– 20). In this publication the authors state that up to 2006 about 140 Petabequerels of technetium had accumulated and that the growth rate of technetium is roughly 5.8 terabequerels per GWy of thermal (primary) nuclear energy production. From these figures, given the yearly average primary nuclear energy production of 28.4 exajoules, one can estimate that nuclear power plants have generated about 303 metric tons of technetium.

Of more interest to me personally than superalloys is the effect of alloying with technetium has on tungsten.

In the early 1960's, based on designs developed in the 1950's, a small test nuclear reactor having liquid plutonium fuel - actually a plutonium/iron eutectic - ran for a few years. This was the LAMPRE reactor. Since I first learned about this reactor, it's intrigued me. At the time of its development, only two metals were known that could contain liquid plutonium, since the liquid metal is quite corrosive to many metals since it dissolves them. One such metal was tantalum; the other was tungsten, both of which are high melting metals. For the actual reactor that was build and operated, tantalum was chosen because tungsten is a poorly machinable metal, particularly because it is brittle and lacks ductility, and the LAMPRE design included capsules featured the use of capsules that could only be made using a machinable metal subject to welding.

Tantalum is now understood to be a conflict metal, which means that it is mined under appalling social conditions, which sometimes include effective slavery for children. (The chief use of this rare metal is in cell phones, where it is useful to make small compact supercapacitors.) In an ethical world, its use would be constrained as much as is possible. For this reason, if one were to build reactors designed to exploit the many powerful features that liquid plutonium and/or its known binary and ternary eutectics – the ability spontaneously to separate fission products on line with in situ extractions, distillations and/or phase separations as well as the ability to instantaneously denature weapons grade plutonium to make it useless for use in weapons – one could not ethically do so using tantalum capsules.

The machinability of tungsten can be greatly improved by alloying it rhenium, but significantly more rhenium is required than is the case with commercial superalloys found in jet engines and gas turbines. Since rhenium is rare and expensive and easily subject to depletion, this does not represent a viable approach to reviving the LAMPRE concept on the industrial scale that would be required for any serious effort to both replace dangerous fossil fuels while cleansing the atmosphere of dangerous fossil fuel wastes, particularly the most dangerous of all, given the implications of climate change, carbon dioxide.

Completed in 1968, about six years after the LAMPRE project was defunded and the reactor shut down, at the Pacific Northwest National Laboratory (PNNL) where plenty of technetium was available since the laboratory is adjacent to the Hanford reservation, experiments were conducted to consider whether technetium offered the same advantages to tungsten alloys that rhenium did. The report on these experiments is here: Concluding Progress Report: A Study of Tungsten-Technetium Alloys (Nelson and O'Keefe, BNWL-865, 1968). It was found that the ductilization of tungsten by alloying with technetium had a transition temperature comparable to that of alloying with rhenium in the range of 3% to 25% technetium.

The phase diagram for the tungsten/technetium system is available on the ASTM database, and I have it in my files. The melting point of pure tungsten, 3422C, falls only to 3000C with the addition of 20% technetium.

The maximum temperature requirement for splitting carbon dioxide to get carbon monoxide and oxygen in one known system (cerium oxide catalysis) is considerably lower than this temperature, around 1400C for the oxygen generating step. The boiling point of strontium metal is 1377C, and of course, lower at reduced pressure. These facts make the properties of the tungsten-technetium alloy intriguing, and suggest that the quantities of technetium available currently – around 300 MT – are huge only if one is considering the metal as “nuclear waste” but small if one is considering the metal as a valuable alloying agent.

When I contemplate potential LAMPRE based reactor designs, I do so in imagining a “breed and burn system, reactors designed to run without refueling for significant fractions of a century. It is interesting to note, as an aside – without going into significant detail about how a tungsten technetium alloy might fit into this system – that a tungsten alloy under neutron irradiation for 7 or 8 decades would result in the transmutation of relatively inexpensive tungsten into the extremely valuable and rare metals including the aforementioned rhenium, the very valuable catalytic metal iridium, as well as osmium. Under the same circumstances, technetium would be transmuted into ruthenium and rhodium, also very valuable metals.

All of the above suggests that there are far more important things to do with technetium than to dump into the Irish Sea, thus causing some whining and crying from say, Norwegians, about detectable technetium in the coastal seas where they drill for oil and gas, the waste products of which end up in the flesh of every living thing on this planet while completely destabilizing the planetary climate.

(Norwegian caterwauling about Sellafield technetium, funded by the Norwegian ministry of fisheries, can be found here: Technetium-99 Contamination in the North Sea and in Norwegian Coastal Areas 1996 and 1997 (Brown et al StrålevernRapport 1998:3))

It is difficult to say what the energy demand of a world that was both sustainable and ethical might be. Current world energy demand, as of 2017, according to the most recent World Energy Outlook published by the International Energy Agency a few weeks ago was 584 exajoules. For a wild guess, let’s say that a world in which the dual goals of eliminating world poverty, eliminating the use of dangerous fossil fuels, and cleaning up the planetary atmosphere by removing much of the dangerous fossil fuel waste carbon dioxide from it – all these goals are synergistic – world energy demand might be on the order of 750 exajoules/year. To achieve these goals, in my view, all of the world’s energy would need to be obtained from nuclear energy, not necessarily via an electricity intermediate, but rather in a very highly thermodynamic efficient manner, wherein electricity might only be a side product from the use of primary nuclear energy to drive chemical reactions and separations.

It is certainly possible to estimate where the secular equilibrium between the formation of technetium and its rate of decay and/or transmutation as a reactor material might lie. (The secular equilibrium point is the point at which technetium would be decaying and/or transmuting at exactly the same rate it is being formed; all radioactive nuclei undergoing formation have such a point, representing the maximal amount that can accumulate.) I have neither the time nor the resources accurately and conveniently to do this estimation, but no matter. This said, using the calculations of the type above, and the Beq/GWy conversion factor, we can estimate that at 750 exajoules/year produced by nuclear fission using U-238 as a fuel in “breed and burn” reactors, roughly 220 tons could accumulate in a single year, and be available for use. The long half-life of Tc-99 suggests that it would be possible to obtain considerable quantities of this valuable metal, surely enough to displace rhenium demand for almost all closed systems demanding its alloys.

To achieve this goal, it is important that as little technetium as is possible be lost to waste, either in seawater or in waste dumps of any kind.

This brings me finally to the paper cited at the beginning of this post, the paper on the extraction of technetium from aqueous solutions using deep eutectic solvents, a capability that, along with separations of other radionuclides, might have well eliminated the need for the wasteful and unpopular Sellafield outfall pipe. (Tim E. Phelps , Nakara Bhawawet , Silvia S. Jurisson* , and Gary A. Baker,* ACS Sustainable Chem. Eng., 2018, 6 (11), pp 13656–13661, cited at the outset.)

For the uninitiated, the authors describe, in their opening paragraph, what a deep eutectic solvent is:

Deep eutectic solvents (DESs) represent an intriguing, potentially sustainable, and unexplored opportunity… …DESs are fluids comprised of components self-associating via complex, dynamical, and correlated hydrogen-bonding networks to produce a eutectic mixture with a melting point below that of its individual components.16−19 Although a typical DES consists of a 1:2 molar ratio mixture of hydrogen-bonding acceptor (HBA) and hydrogen-bonding donor (HBD) species (e.g., choline chloride coupled with urea: a standard DES referred to as reline), unconventional DESs including halide-free examples20 and hydrophobic (water-immiscible) versions have recently emerged as well.


They continue:


In the present communication, we demonstrate for the first time the efficient and selective extraction of trace 99mTcO4 − from aqueous solutions using hydrophobic DESs. The component structures of the three hydrophobic DESs were varied by the choice of HBA cation (trihexyltetradecylphosphonium, [P14,666 +], or tetraoctylammonium, [N8888 +]) and fatty acid as HBD species (hexanoic or decanoic acid), combined in a 1:2 (HBA/HBD) molar ratio (Figure 1). We note that the DES comprising 1:2 [N8888][Br-]/[DecA] (denoted DES B in this communication) has already been reported and characterized previously.21


A picture from the paper showing the structures of these deep eutectic solvents might clarify any difficulty associated with the chemical names:



The caption:

Figure 1. DESs examined for 99mTcO4 − extraction capability. DES A consists of a 1:2 molar ratio of trihexyltetradecylphosphonium chloride ([P14,666][Cl]) and decanoic acid (also known as capric acid); DES B consists of a 1:2 molar ratio of tetraoctylammonium bromide ([N8888][Br]) and decanoic acid; DES C comprises a 1:2 molar ratio of [N8888][Br] and hexanoic acid (caproic acid).


The use of these solvents is investigated for two purposes: One is to recover technetium from aqueous processing solutions and the other is to remove it from contaminated environmental matrices, for example groundwater. For this reason, the authors investigate its use in the presence of many common anions, chloride, phosphate, nitrate, carbonate, etc. They also add perrhenate to the equation to examine their utility in separating these two closely related species.

The measure the extraction efficiency and distribution coefficients (measures of the selectivity of the extractions) they use very dilute solutions, and utilize Tc-99m, not Tc-99, because of its higher activity, and thus ease of detection, in very dilute solutions.





The caption:

Figure 2. Percentage of 99mTcO4 − extracted by hydrophobic DESs A−C after 60 min of extraction at 25 °C for a 1:1 (v/v) ratio of DES to aqueous phase while stirring at 2000 rpm. The aqueous phase contained 0.15 M of the following competing anions; left to right: HCO3 − (brick red), Cl− (orange), NO3 − (blue), H2PO4 − (pink), SO4 2− (purple), I− (yellow), or ReO4 − (green). Five μL aliquots from each sample were counted for quantification (n = 3).


The distribution ratios are also very high:



The caption:

Figure 2. Percentage of 99mTcO4 − extracted by hydrophobic DESs A−C after 60 min of extraction at 25 °C for a 1:1 (v/v) ratio of DES to aqueous phase while stirring at 2000 rpm. The aqueous phase contained 0.15 M of the following competing anions; left to right: HCO3 − (brick red), Cl− (orange), NO3 − (blue), H2PO4 − (pink), SO4 2− (purple), I− (yellow), or ReO4 − (green). Five μL aliquots from each sample were counted for quantification (n = 3).


The effect of volume ratios and time of extraction is examined.

Volume:



The caption:

Figure 4. Distribution ratios of 99mTcO4 − after a 60 min extraction at 25 °C (2000 rpm) using (A) 1:10, 1:20, and 1:50 (v/v) ratios of DES to aqueous phase containing 0.15 M I− or using (B) 1:5 and 1:10 (v/ v) ratios of DES to aqueous phase containing 0.15 M ReO4 −. Entire samples were counted for quantification (n = 3).


Time:



The caption:

Figure 5. Distribution ratios of 99mTcO4 − after 0, 5, 10, and 60 min extractions at 25 °C for a 1:50 (v/v) ratio of DES A to aqueous phase containing either 0.15 M HCO3 − (brick red) or 0.15 M Cl− (orange). Also shown are results for a 1:5 (v/v) ratio of DES A to aqueous solution containing 0.15 M ReO4 − (green). Entire samples were counted for quantification (n = 3).


However back extraction, recovery of the technetium from the deep eutectic solvent using another solvent solution is somewhat problematic, at least for the few solvents explored:



The caption:

Figure 6. Percentage of 99mTc back extracted from hydrophobic DESs A−C after 3 h at 25 °C using 0.500 mL solutions containing 0.15 M citrate, 0.1 M HCl, and 5 mg/mL Sn(II) reducing agent (pH 5). DESs used in these experiments were previously used to extract 99mTcO4 − from 0.15 M Cl− (1:50, v/v) or 0.15 M I− (1:10, v/v) aqueous solutions. Entire samples were counted for quantification (n = 3).


In their conclusion the authors refer to this problem and propose, but do not claim to have explored alternative solutions to this problem:

In summary, hydrophobic DESs comprising a 1:2 molar ratio of a tetraalkylammonium (or tetraalkylphosphonium) halide and a monocarboxylic acid are demonstrated to be excellent media for the extraction and separation of trace 99mTcO4 − in the presence of a variety of competing anions within 5−60 min at 25 °C. The partitioning efficiency of 99mTcO4 − was competitive with, or more efficient than, many previously known extraction methods and is dependent upon factors such as the nature of the competing anion(s), choice of HBD constituent, and solution pH. Importantly, anions commonly found in the environment (i.e., HCO3 −, Cl−, NO3−, H2PO4 −, and SO4 2− do not impede 99mTcO4 − extraction. Unsurprisingly, the ReO4 − anion suppresses 99mTcO4 − extraction when present in stoichiometric amounts relative to the DES. Attempts at back extraction showed limited success, although a number of avenues (e.g., Zn reduction, electrodeposition) can be considered for sequestering 99Tc from the spent DES in the future.

Given their favorable properties and low extraction volumes required, the current results have important ramifications for emerging applications using hydrophobic DESs for the extraction and separation of important tetra-oxo anions and radionuclides listed as priority pollutants by the U.S. Environmental Protection Agency, particularly for removing low levels of TcO4 − from contaminated groundwater and potentially for remediating other metalate pollutants such as perchlorate as well...


In their conclusion they also discuss certain modified PUREX like solvent extraction procedures, and the potential utility of their system for cleaning up solvents utilized in it.

I should say that personally, I'm not a solvent extraction (PUREX, UREX, TRUEX…) kind of guy in general, and prefer the development pyroprocessing electrochemical approaches given recent improvements in the electrochemical reduction of metal cations to the metals. My ideas about these processes, involving esoteric molten salts of various types, however may include liquid membranes as separation tools, and thus the existence of ionic liquids, which these deep eutectic solvents are a subset, demonstrating immiscibility with aqueous solutions are always of interest to my ruminations on this topic.

I realize that this post is fairly technical and long, and that few people will read it, and fewer will derive any value from it. My real purpose in writing it was not to convince anyone of anything - where nuclear issues are concerned, most people regrettably have closed minds, much to the detriment of humanity, and, or course, the environment - but rather to clarify and expand on some old ideas in my own mind.

A few paragraphs in this post have come from the saved text of another post I posted elsewhere on the internet, but which has disappeared, probably because the website on which I posted it (Energy Collective) has been acquired and archives have been deleted. That post focused primarily on the use of technetium in superalloys, since I was not even aware of issues in the LAMPRE reactor at that time, and had given no thought at all to the machinability of tungsten.

I personally had a wonderful weekend. Both of my sons came home to visit us and I got to spend lots of time with them and with my wife and extended family.

I trust and hope yours was as wonderful as mine.







A Return to Extraordinary Weekly Year to Year Increased CO2 Readings at Mauna Loa: 11/11/18

I keep a spreadsheet of weekly readings at Mauna Loa which calculates the difference (almost always positive) between a particular reading and the same reading of the same week the year before.

There are 2,233 such readings as of this writing, stretching back to May 25, 1975.

The top 50 readings range from a 5.04 ppm increase in a single year, recorded on July 31, 2016, to a 3.60 ppm increase recorded on May 26, 2013.

Twenty-eight of the top 50 occurred in 2016, which was an El Nino year.

This makes up the bulk of the 30 out of top 50 recorded in the last 5 years. There were two readings in this class in 2017, a post El Nino year. Thirty-six of the top 50 occurred in the last 10 years. Thirty-nine of the top 50 occurred in the 21st century.

Eight of the top 50 occurred in 1998, also a El Nino year, during which huge swathes of the South East Asian Rain Forest burned when fires set to clear forest to create palm oil plantations for "renewable" biodiesel fuel went out of control.

Two readings in 1988 were in the top 50.

One was in 1980.

2018 has been a post El Nino year; typically these are milder in terms of carbon dioxide increases to the El Nino years themselves. There were actually three readings in 2018 that recorded rises as compared to the same week of the year before that were less than 1.00 ppm, something not observed since 2015, when one such rise was recorded.

Well, finally, in 2018 we've got a figure breaking into the top 50. The week ending 11/11/2018 recorded a value of 3.63 ppm over the same week last year. It is the 28th highest increase out of 2,233 readings.

Some people think that solar and wind energy will save the day. They have not saved the day; they aren't saving the day; and they won't save the day. The reason is physics.

I recently referred to the most recent 2018 World Energy Outlook, published a week ago by International Energy Agency (IEA).

That post, which was largely, as I expected, ignored because um, truth is unpopular - especially when couched in a sarcastic title - is here: 2018 World Energy Outlook: Solar and Wind Grew by 11.24% in 2017; Gas by "Only" 3.32%!!!!

It reported that world energy consumption rose from 2016 to 2017 by 8.88 exajoules. Of that 8.88 exajoules, the bulk of it came from increases in the use of dangerous natural gas, which grew by 4.19 exajoules. (Coal based energy production, which some people report as "dead" - even though it remains the fastest growing source of energy in the 21st century - fell by a paltry 0.21 exajoules. It's not "dead." It's not even ill. It still produces 157.01 exajoules out of the 582.84 exajoules reported by the IEA, and is exceeded only by oil, which provided 185.68 exajoules in 2017, an increase of 1.97 exajoules.)

The combined solar, wind, geothermal, and tidal energy on which humanity has foolishly chosen to bet the planetary atmosphere, grew by 1.21 exajoules, and thus grew less than dangerous petroleum did, less than dangerous natural gas did. It did record an insignificant milestone however. For the first time, these four forms of so called "renewable energy" - even if the material requirements make anything other than "renewable" exceeded 10 exajoules: 10.63 exajoules to be exact.

The reading at Mauna Loa for the week ending 11/11/18 was 408.72 ppm.

No one now living will ever see a reading there of under 400 ppm again.

I'd like to congratulate all those people who carried on using gas and coal powered computers in this century about how "dangerous" nuclear energy is. I'd like to ask some of them, "Compared to what?" but there's no point in it. Experience teaches that their definition of "danger" does not include the 7 million people who died from air pollution in 2017. Because of their confused and selective attention, nuclear remains pretty static, having been producing around 28 exajoules of primary energy consistently throughout the 21st century, all the while accompanied by cacophony by scientific illiterates about how it "has to go." Were it not for fear and ignorance, it might have done more to save lives and fight climate change, but that was not to be.

The die is cast.

Have a wonderful Thanksgiving.



An interesting discourse on the biological marine sulfur cycle.

The paper I'll discuss in this post is this one: The metabolite dimethylsulfoxonium propionate extends the marine organosulfur cycle (Kathleen Thume, Björn Gebser, Liang Chen, Nils Meyer, David J. Kieber & Georg Pohnert, (Nature Volume 563, pages 412–415 (2018))

When I was a kid, one of my first professional successes in the lab involved the hydrophobic amino acid methionine, which is one of two of the 20 proteogenic amino acids (21 if one counts bacteria) for which genetic codons exist. Methionine is one of two members of this class which contains sulfur, the other being cysteine.

The role of cysteine, a thiol, in proteomics is spectacular, since its oxidative interaction with other cysteines in proteins is responsible for disulfide bridges without which many proteins would be useless, lacking the requisite geometry, and almost equally important, its role in metal co-ordination at catalytic centers of very important proteins. Methionine, a thioether rather than a thiol is far more rare in proteins, although it is important in the transfer of methyl groups in biological interactions and it has recently been discovered that interactions with the π systems in phenylalanine, tyrosine and - who knows - histidine also serve to stabilize protein geometry. Bacterial methionine biosynthesis (Ferla and Patrick, Microbiology (2014), 160, 1571–1584).

I am also interested in the chemistry of sulfur, because my generation failed all future generations by turning out planetary atmosphere into a vast waste dump for the dangerous fossil fuel waste carbon dioxide, and I am always thinking about ways that future generations can clean up our mess, and do so with a functionally destroyed resource base consisting almost entirely of our solid phase garbage dumps. One path to removing carbon dioxide from the atmosphere is to essentially reverse combustion by making the source of carbon materials - now made from dangerous fossil fuels - carbon oxides obtained by the thermal reformation (gasification) of waste (or problematic) biomass, using nuclear energy as the primary energy source. These technologies are being widely explored but a consistent factor that engineers must address is the fate of heteroatoms in biomass like potassium, sodium and, relevant to this discussion, sulfur.

Finally the paper cited at the outset of this post caught my eye because I always wonder about the environmental fate of common laboratory chemicals - one of which is dimethylsulfoxide - a wonderful solvent with wide use - and also because of my interest in stable charged organic species that play a role in a rapidly developing area of chemistry, ionic liquids.

So the paper itself:

From the abstract:

Algae produce massive amounts of dimethylsulfoniopropionate (DMSP), which fuel the organosulfur cycle1,2. On a global scale, several petagrams of this sulfur species are produced annually, thereby driving fundamental processes and the marine food web1. An important DMSP transformation product is dimethylsulfide, which can be either emitted to the atmosphere3,4 or oxidized to dimethylsulfoxide (DMSO) and other products5...


So it turns out that DMSO, which is used in some products for joint pain, is a normal biological species, present in the oceans on what may be a million ton scale. (I had a neighbor - to whom I stopped speaking years ago - who called me up to ask me if he could sue his employer because they asked him to work with this chemical, but that's another story.) That makes me feel better about all the DMSO I've used - or asked scientists working for or with me to use - in my career, for solvation, Swern oxidations, blah, blah, blah...

From the introduction to the paper:

The marine organosulfur cycle is fuelled by small sulfur-containing zwitterionic osmolytes that are primarily produced by planktonic algae. The main metabolite of this class, DMSP, is produced in the impressive amounts of 2 petagrams (2 × 109 tons) sulfur annually1. Cellular DMSP serves important physiological functions in marine algae that include, but are not limited to, acting as an osmolyte, a cryoprotectant and an antioxidant6,7. Enzymatic lysis of DMSP by DMSP lyases in bacteria and algae yields acrylate and dimethylsulfide (DMS)8. Volatile DMS is the main source of organosulfur in the atmosphere; and with an annual flux of approximately 30 teragrams of sulfur3, DMS has been proposed to affect cloud formation and regulate climate4. Dissolved DMSP arising from exudation, grazing, viral lysis and cell mortality serves as substrate for marine microorganisms7,9,10. In surface waters, substantial quantities of dissolved DMSP and DMS can be detected, but often the concentration of dissolved DMSO exceeds the concentration of each of these two species5,11. DMSO is mainly produced from bacterial and photochemical DMS oxidation12, but algal sources of DMSO may also be important13 The marine organosulfur cycle is fuelled by small sulfur-containing zwitterionic osmolytes that are primarily produced by planktonic algae. The main metabolite of this class, DMSP, is produced in the impressive amounts of 2 petagrams (2 × 109 tons) sulfur annually1. Cellular DMSP serves important physiological functions in marine algae that include, but are not limited to, acting as an osmolyte, a cryoprotectant and an antioxidant6,7. Enzymatic lysis of DMSP by DMSP lyases in bacteria and algae yields acrylate and dimethylsulfide (DMS)8. Volatile DMS is the main source of organosulfur in the atmosphere; and with an annual flux of approximately 30 teragrams of sulfur3, DMS has been proposed to affect cloud formation and regulate climate4. Dissolved DMSP arising from exudation, grazing, viral lysis and cell mortality serves as substrate for marine microorganisms7,9,10. In surface waters, substantial quantities of dissolved DMSP and DMS can be detected, but often the concentration of dissolved DMSO exceeds the concentration of each of these two species5,11. DMSO is mainly produced from bacterial and photochemical DMS oxidation12, but algal sources of DMSO may also be important13. Common pelagic bacteria use monooxygenases to oxidize DMS to DMSO14, a process that may serve as an energy source15. Here we report on the identification of the zwitterionic metabolite DMSOP, which is widely distributed in phytoplankton and also produced by marine bacteria. This metabolite is the substrate of a previously undescribed marine pathway for DMSO production (Fig. 1) .


It's probably now time to just look at the pictures the authors use to describe their "zwitterionic" species. (A zwitterion is a molecule that possesses, in the same molecule, both a positively and a negatively charged ion. The important physiological molecule carnitine is an example of a zwitterion.)

A picture:



The caption:

DMSOP and the transformations labelled with red arrows extend the established marine sulfur cycle. DMSOP is produced in eukaryotic microalgae (green) as well as in bacteria (purple). Bacteria metabolize DMSOP and therefore contribute to the marine DMSO pool. The established DMSP-based part of the sulfur cycle is indicated with grey arrows. DMSP is formed by marine algae and bacteria. It is then cleaved by algal and bacterial DMSP lyases to DMS and acrylate (not shown). The subsequent biological and photochemical oxidation of DMS to DMSO, sulfate and other products can occur within algae, bacteria, in the seawater and the atmosphere.


A picture describing some of the techniques they used to find out about DMSOP:



The caption:

a, Chromatographic profile of zwitterionic metabolites from a P. minimum culture, separated using ultra-high-pressure liquid chromatography (UHPLC) with detection by electrospray ionization mass spectrometry (ESI-MS). The total ion current is shown in grey. The metabolites glycine betaine (GBT, cyan), dimethylsulfonioacetate (DMSA, orange), DMSP (black) and gonyol (blue) were assigned according to a previous study16. The ion trace of DMSOP, red, is shown at a tenfold magnification. b, Synthesis of authentic (labelled) DMSOP. c, Mass spectrum and tandem mass spectrum (inset) of DMSOP with characteristic fragments. d, UHPLC profile monitoring m/z = 151 of an extract of P. parvum (solid line) and the same extract treated with synthetic DMSOP in roughly equal amounts (dashed line), the experiment was repeated three times with varying concentrations of synthetic DMSOP to confirm co-elution.


Biosynthetic pathways:



The caption:

a, High-resolution mass spectrum of DMSOP obtained from P. bermudensis incubated for 24 h with 13C2-labelled DMSP (Fig. 2). The peak labelled in red represents 13C2-labelled DMSOP, the natural DMSOP isotopes are shown in black (see also Extended Data Table 3). b, c, DMSO release (concentration (c) given as mean ± s.d.) of the bacteria Sulfitobacter sp. and R. pomeroyi incubated with 1 µM DMSOP. P values directly over bars indicate significant difference from t = 10 min of the same treatment, P values over brackets indicate significant difference between treatment and the control without DMSOP addition. n = 4 independent biological replicates for 24 h, n = 3 for 10 min and 5 h, for statistical details see Methods.


From the conclusion:

Our results demonstrate that the ubiquitous zwitterionic metabolite, DMSOP, contributes to the marine DMSO pool and may partly account for DMSO in marine algae13. In light of our findings, a functional role of DMSP as an oxygen acceptor is probable and could explain numerous observations of DMSP regulation under oxidative stress. Algal and bacterial DMSOP biosynthesis and its bacterial degradation to DMSO represent a previously undescribed pathway for DMSO production, extending our current paradigm of the marine sulfur cycle beyond the established biotic and photochemical pathways through DMS oxidation



Esoteric things like this are actually very important, particularly in light of the disturbance to the sulfur cycle represented by the rapidly increasing use of dangerous fossil fuels as we all wait, like Godot, for the grand "renewable energy" "revolution" that never comes.

I wish you a very pleasant weekend, and hope your Thanksgivings plans are proceeding nicely.

Science candidates prevail in US midterm elections.

I had the privilege of having a Congressperson who was a scientist - Rush Holt - until he retired. Before being elected to Congress, Dr. Holt was the Assistant Director of the Princeton Plasma Physics labs.

While I didn't always agree with everything he said or did, overall he was a magnificent congressperson, the best Congressperson I ever experienced by orders of magnitude, which is not to say that his replacement, Bonnie Watson Coleman is a bad Congressperson, only that Rush Holt was the best, by far.

He should have been our Senator, but didn't come close in the only race he entered; won by Corey Booker; Rush wasn't flashy, just solid, decent, extremely intelligent, thoughtful, concerned with justice, open, helpful and responsive.

(For the record, the worst Congressperson I ever had was Randy "Duke" Cunningham, who happily went to prison directly from Congress.)

My tempered joy aside, it appears that our new congress will include several scientist/legislators. From Nature:

Science candidates prevail in US midterm elections (Jane J. Lee,
Amy Maxmen, Jeremy Rehm & Jeff Tollefson Nature 563, 302-303 (2018))

The results of the political experiment are in. At least 11 candidates with backgrounds in science, technology, engineering or medicine won election to the US House of Representatives on 6 November — including several who had never before run for political office.

They include Elaine Luria, a US Navy veteran and nuclear engineer in Virginia, and Chrissy Houlahan, a former business executive with a degree in engineering, in Pennsylvania. Illinois saw wins by registered nurse Lauren Underwood, a former senior adviser to the Department of Health and Human Services, and clean-energy entrepreneur Sean Casten, who has degrees in engineering and biochemistry.

The four — all Democrats — are among roughly 50 candidates with science backgrounds who ran for the House in 2018, sparked in part by opposition to President Donald Trump. Fewer than half of these novice politicians made it past the primaries to the general election, but many science advocates are already looking to the next campaign cycle.

“I’m feeling good,” says Representative Bill Foster (Democrat, Illinois), a physicist who has pushed to increase the number of scientists in elected office. Foster, the only current member of Congress with a science PhD, is excited about wins at the state and local levels by candidates with backgrounds in science, technology, engineering or medicine (STEM).


I am personally pleased to see a Democratic nuclear engineer elected, which is why I bolded her discipline in the excerpt above. If I have any difficulty with my fellow Democrats, it is with those who promote what I regard as our creationism, anti-nukism, which marks us a climate change hypocrites, too prevalent in the party to which Nobel Laureate Glenn Seaborg proudly belonged - he headed the AEC when most of our life saving nuclear infrastructure was built - is finally going the way of other anti-science stuff one hears, anti-vax, anti-GMO, etc., etc, that have also represented poisoned wings of our party.

We have no hope, absolutely no hope, of addressing the most severe environmental crisis experienced by human civilization without nuclear energy. I'm glad someone's there who can understand this.

If there's any civil lining on the reign of the orange naked emperor, it is that his attacks on science have raised awareness among scientists of what the stakes are, a new dark and poisoned age, or an age in which knowledge and intellect triumph.

Congrats to our new STEM scientist/congresspeople.

2018 World Energy Outlook: Solar and Wind Grew by 11.24% in 2017; Gas by "Only" 3.32%!!!!

We're Saved!!!!

Right? Right?

I have before me a PDF of the World Energy Outlook for 2018, which was released by the International Energy Agency yesterday.

I also have opened a PDF of the World Energy Outlook for 2017, which I have discussed in many threads in this space.

The data I will discuss here is collected from World Energy Outook 2018, Table 1.1 Page 38 and, for World Energy Outook 2017, Table 2.2 Page 79.

In each case, the data refers to the year before the title year, that is WEO 2018 refers to 2017's data; WEO 2017 refers to 2016. (In earlier editions of the WEO, the lag was 2 years and not 1 year, but reporting has apparently grown quicker.)

These tables give values in "MTOE," or "Million Tons Oil Equivalent." In my discussion, as my habit, all data will be converted to the SI unit the Exajoule, except of course, that wonderful "percent talk" used here by people who still believe that it was a good idea to bet the future of every generation to come, the climate, the planetary atmosphere on so called "renewable energy."

The tables break so called "renewable energy" into three categories, hydro, bioenergy, and "other," "other" referring to solar and wind primarily, with a little tidal and geothermal presumably thrown in. In the title of this post I have ignored tidal and geothermal - which I know to be trivial with respect to solar and wind.

In 2016, "other" renewables, again chiefly solar and wind, produced 9.42 exajoules of energy. In 2017, they produced 10.63 exajoules. In "percent talk" this represents the growth of 11.42% as described in the title. In terms of energy, the growth, which can be found by using an operator called "subtraction" was 1.21 exajoules. In 2016 dangerous natural gas produced 125.90 exajoules of energy; in 2017 it produced 130.08 exajoules. In "percent talk" this represents a growth of 3.32% as described in the title here. Of course, in absolute terms, dangerous natural gas grew by 4.19 exajoules.

In "percent talk," gas thus grew 100 * 4.19/1.21 = 345% faster than wind and solar combined.

Overall, world energy consumption grew from 576.10 exajoules in 2016 to 584.98 exajoules in 2018, or 8.88 exajoules.

World energy consumption thus grew 8.88/1.21 * 100 = 731% faster than solar and wind.

What I personally regard as the only sustainable form of energy on the planet, albeit an unpopular form of energy, nuclear energy, grew by 0.29 exajoules, or only 0.29/1.21 * 100 = 24% as fast as solar and wind.

The mistake of confusing what is popular with what is right is known as the logical fallacy of appeal to popularity or at other times the "Bandwagon Fallacy."

The example in the link just presented of the "Appeal to Popularity" fallacy is this:

A 2005 Gallup Poll found that an estimated 25% of Americans over the age of 18 believe in astrology—or that the position of the stars and planets can affect people's lives. That is roughly 75,000,000 people. Therefore, there must be some truth to astrology!


In the last ten years, 2.3 trillion dollars has been "invested" in solar and wind energy:

Frankfurt School/UNEP Global Renewable Energy Investment, 2018, Figure 3, page 14

This is more than the gross national product of India, a nation with 1.3 billion people in in it.

On the planet as a whole, 2.3 billion people lack access to any kind of improved sanitary facilities; but no one is going to spend 2.3 trillion dollars to change that, not while we can all dream of solar and wind powered Tesla electric cars.

For the Week Ending November 4, 2018 (Accessed 11/14/18) the concentration of the dangerous fossil fuel waste carbon dioxide in the planetary atmosphere as measured at the Mauna Loa observatory was 406.99 ppm. In the same week 10 years ago, the concentration was 383.80 ppm.

No one now living will ever see a measurement at this site of below 400 ppm again, no matter how many miles Bill McKibben drives in his Prius with a "350.org" bumper sticker on it.

We have not been saved by the 11.24% growth in solar and wind in 2017, and are not being saved by it, and no such "percent talk" announcements in the future will represent us being saved.

We are clueless.

Facts matter.

Have a nice day tomorrow.
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