Multielemental determination of GEOTRACES key trace metals in seawater by ICPMS after preconcentration using an ethylenediaminetriacetic acid chelating resin

GEOTRACES is an international research project on marine biogeochemical cycles of trace elements and their isotopes. GEOTRACES key trace metals in seawater are Al (8-1000 ng/kg), Mn (4-300 ng/kg), Fe (1-100 ng/kg), Cu (30-300 ng/kg), Zn (3-600 ng/kg), and Cd (0.1-100 ng/kg), of which global oceanic distribution will be determined on a number of research cruises. This work introduces a novel method of solid-phase extraction to determine Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb in seawater by adjusting the pH of the sample to 6 and carrying out a single preconcentration step. The trace metals were collected from approximately 120 mL of seawater using a column of a chelating resin containing the ethylenediaminetriacetic acid functional group and eluted with approximately 15 mL of 1 M HNO3. Mn and Fe in the eluate were measured by inductively coupled plasma mass spectrometry (ICPMS) using the dynamic reaction cell mode, and the other metals were measured using the standard mode. Using this procedure, the trace metals were collected quantitatively, while >99.9% of alkali and alkaline earth metals in seawater were removed. The procedural blank was <7% of the mean concentration in deep ocean waters, except 16% for Pb. The overall detection limit was <14% of the mean concentration in deep ocean waters. The RSD was <9%. Our values for the trace metals in the certified reference materials of seawater NASS-5 and nearshore seawater CASS-4 agreed with the certified values (except that there is no certified value for Al). This method was also successfully applied to the reference materials of open-ocean seawater produced by the SAFe program. Our Fe concentrations were 5.9 +/- 0.7 ng/kg for surface water (S1) and 50.4 +/- 2.9 ng/kg for deep water (D2), which are in agreement with the interlaboratory averages of 5.4 +/- 2.4 and 50.8 +/- 9.5 ng/L, respectively. The data for other metals were oceanographically consistent.     

Microwave-Resonance Induced Change in Magneto-Resistivity: Hot Surface Electrons on Liquid 3He

Behaviour of the linear magneto-resistivity σ _xx ⁻¹ of the surface-state electrons (SSE) exposed to the microwave radiation is studied in a wide temperature range which covers both vapor-atom and ripplon scattering regimes. The microwaves induce the resonance transitions of SSE between two lowest Rydberg states, and σ _xx ⁻¹ is observed to vary in the vicinity of the resonance. In the vapor-atom scattering regime (T≳0.5 K), magneto-resistivity decreases at the resonance, while in ripplon scattering regime (T≲0.3 K) it rapidly increases with the microwave power in the given range of the pressing electric field. The observed variation of σ _xx ⁻¹, which under the conditions of our experiment is inversely proportional to the scattering rate, is attributed to the strong heating of SSE. The heating results in the increase of electron temperature well above ambient temperature and in significant thermal population of higher excited states. The theoretical predictions are found to be in good agreement with our experimental results in the whole temperature range.      

Cross-polarization/magic-angle spinning 13C nuclear magnetic resonance study of cellulose I-ethylenediamine complex

Complete assignments of the cross-polarization/magic-angle spinning (CP/MAS) 13C nuclear magnetic resonance (NMR) spectrum of the cellulose I-ethylenediamine (EDA) complex, which is the intermediate of the reaction from cellulose I to cellulose III(I), were performed. In this paper, we used the 13C-enriched cellulose that was biosynthesized by Acetobacter xylinum ATCC10245 strain from culture medium containing D-(2-13C), D-(3-13C), or D-(5-13C)glucose as a carbon source. After conversion into cellulose I-EDA complex by sufficient EDA treatment, the CP/MAS 13C NMR spectra of the 13C-enriched cellulose I-EDA complexes were measured. As a result, 13C resonance lines of each carbon of the cellulose moiety in the complex appeared as a singlet, suggesting that all glucose residues of the complex are magnetically equivalent. The difference in chemical shifts for each carbon between cellulose I-EDA and cellulose I(alpha), I(beta), and III(I), respectively, suggests that the conformation of the cellulose chains for cellulose I-EDA differs from that for cellulose I(alpha), I(beta), and III(I). In addition, fitting analysis of the 13C spectrum of Valonia cellulose I-EDA complex revealed that the complex contains one EDA molecule per two glucose residues in the cellulose chain.     

A rapid method to isolate soluble royal jelly proteins

Soluble royal jelly (RJ) proteins (SRJPs) include the major RJ protein (MRJP) family, which contribute to the physiological actions of RJ. Although SRJPs are prepared using conventional methods involving dialysis and centrifugation, dialysis is a time-consuming process. We have therefore developed a simple method to isolate SRJPs from RJ. This new method produces 20-fold higher levels of SRJPs than that of the conventional procedure; hence, the levels obtained by the new and existing methods were compared. A 1-h ultracentrifugation separated SRJPs in the supernatant into upper, middle and lower layers. Each layer was analyzed by size-exclusion HPLC, SDS–PAGE and 2-DE. The upper and middle layers contained MRJP2 (52 kDa) and MRJP3 (60–70 kDa), while the lower layer contained MRJP1 (290 kDa). In nature, MRJP1 is a monomer and/or oligomer. When the lower layer was analyzed by Superose 12 HPLC, MRJP1 was predominantly an oligomer. Our MRJP isolation method reduces the procedure time by using ultracentrifugation without dialysis to obtain SRJPs and produces layers containing MRJP1 oligomers, MRJP2 and MRJP3.     

Survey on the quality of commercial Nigari (crude magnesium chloride [sea water])

Contents of minerals (Mg, Ca, Na and K), anions (SO4(2-), Br- and Cl) and heavy metals (Pb, Cd, Zn, Hg and As) were determined in 17 commercial samples of Nigari, 15 samples of crude magnesium chloride (sea water) products as a food additive and 2 magnesium-containing foods. Obtained values were compared with the specifications proposed in a draft of the eighth edition of Japan's Specifications and Standards for Food Additives. Out of 15 food additive samples, only 5 samples satisfied the specification. Since the Joint FAO/WHO Expert Committee on Food Additives (JECFA) proposed to lower the limits of heavy metals in food additives, a simple method was developed for the determination of low levels of Pb and Cd by extracting chelates of these metals with organic solvents. The quantification limits for Pb and Cd were 0.5 microg/g and 0.05 microg/g, respectively. It was estimated from the SO4(2-)/Ca ratios that 15 samples were sea water evaporation products, and the remaining 2 were ion-exchange membrane process products. No pollution with heavy metals was found in any of the samples.     

A Highly Active 4‐Siloxyproline Catalyst for Asymmetric Synthesis

trans‐4‐tert‐Butyldimethylsiloxy‐L ‐proline displays a greater catalytic activity than the parent proline without compromising the enantioselectivity, which widens the substrate scope in the α‐aminoxylation of carbonyl compounds, as well as O‐nitroso‐aldol/Michael, and Mannich reactions.     

Inhibition of cell growth by a fused protein of human ribonuclease 1 and human basic fibroblast growth factor

Pancreatic-type RNases are considered to have cytotoxic potentialdue to their ability to degrade RNA molecules when they enterthe cytosol. However, most of these RNases show little cytotoxicitybecause cells have no active uptake mechanism for these RNasesand because the ubiquitous cytoplasmic RNase inhibitor is consideredto play a protective role against the endocytotic leak of RNasesfrom the outside of cells. To study the cytotoxic potentialof RNase toward malignant cells targeting growth factor receptors,the C-terminus of human RNase 1 was fused to the N-terminusof human basic fibroblast growth factor (bFGF). This RNase–FGFfused protein effectively inhibited the growth of mouse melanomacell line B16/BL6 with high levels of cell surface FGF receptor.This effect appeared to result from prolongation of the overallcell cycle rather than the killing of cells or specific arrestin a particular phase of the cell cycle. Thus, human RNase 1fused to a ligand of cell surface molecules, such as the FGFreceptor, is shown to be an effective candidate for a selectivecell targeting agent with low toxic effects on normal cell types.     

Theory of the AC Josephson effect in triplet superconducting junction

The quasiparticle and AC Josephson current in superconductor / insulator / superconductor (S/I/S) junctions including a triplet p-wave superconductor are calculated for arbitrary transmission of the junction. As a triplet pairing state we select one of the unitary pairing states which is a promising candidate for the superconducting state in Sr ₂ RuO ₄ . In p-wave superconductor / insulator /p-wave superconductor junction, both quasiparticle current and AC Josephson current are enhanced near zero-bias voltage due to the existence of zero energy state of p-wave superconductors. For the s-wave superconductor/ insulator / p-wave superconductor junction, the quasiparticle current at low voltage is suppressed due to the energy gap of s-wave superconductor. The first Fourier component of the AC Josephson current vanishes due to the difference of the parity between the two superconductors.     

Phospholipid-Coated Boronic Oxide Nanoparticles as Boron Agents for Boron Neutron Capture Therapy

Minimally invasive boron neutron capture therapy (BNCT) is an elegant approach for cancer treatment. The highly selective and efficient deliverability of boron agents to cancer cells is the key to maximizing the therapeutic benefits of BNCT. In addition, enhancement of the frequencies to achieve boron neutron capture reaction is also significant in improving therapeutic efficacy by providing a highly concentrated boron agent in each boron nanoparticle. As the density of the thermal neutron beam remains low, it is unable to induce high-efficiency cell destruction. Herein, we report phospholipid-coated boronic oxide nanoparticles as agents for BNCT that can provide a highly concentrated boron atom in each nanoparticle. The current system exhibited in vitro BNCT activity seven times higher than that of commercial boron agents. Furthermore, the system could penetrate cancer spheroids deeply, efficiently suppressing thermal neutron irradiation-induced growth.