Hydrogen analysis in solid samples by utilizing He metastable atoms induced by TEA CO2 laser plasma in He gas at 1 atm

A TEA CO₂ laser (350 mJ–1.5 J, 10.6 μm, 200 ns, 10 Hz) was focused onto a metal sub-target under He as host gas at 1 atmospheric pressure with a small amount of impurity gas, such as water and ethanol vapors. It was found that the TEA CO₂ laser with the help of the metal sub-target is favorable for generating a strong, large volume helium gas breakdown plasma at 1 atmospheric pressure, in which the helium metastable-excited state was then produced overwhelmingly. While the metal sub-target itself was never ablated. The helium metastable-excited state produced after the strong helium gas breakdown plasma was considered to play an important role in exciting the atoms. This was confirmed by the specific characteristics of the detected H emission, namely the strong intensity with low background, narrow spectral width, and the long lifetime. This technique can be used for gas and solid samples analysis. For nonmetal solid analysis, a metal mesh was introduced in front of the nonmetal sample surface to help initiation of the helium gas breakdown plasma. For metal sample, analysis can be carried out by combining the TEA CO₂ laser and an Nd–YAG laser where the Nd–YAG laser is used to ablate the metal sample. The ablated atoms from the metal sample are then sent into the region of helium gas breakdown plasma induced by the TEA CO₂ laser to be excited through the helium metastable-excited state. This technique can be extended to the analysis of other elements, not limited only to hydrogen, such as halogens.     

Multiple enzyme linked immunosorbent assay system on a capillary-assembled microchip integrating valving and immuno-reaction functions

Gastrodin is a bioactive constituent of rhizome in Gastrodia elata Blume (Orchidaceae) The aim of this study is to develop a rapid and sensitive liquid chromatographic method coupled to microdialysis sampling system to measure the unbound of gastrodin in rat blood, brain and bile. Microdialysis probes were simultaneously inserted into the jugular vein, brain striatum and bile duct of each anesthetized rat for sampling after the administration of gastrodin (100 or 300 mg kg⁻¹) through the femoral vein. Separation of unbound gastrodin from various biological fluids was applied to an RP-select B column (250 mm × 4.6 mm i.d., 5 μm). The mobile phase consisted of acetonitrile–50 mM potassium dihydrogen phosphate buffer–triethylamine (5:95:0.1, v/v/v, adjusted to pH 2.5 with orthophosphoric acid) with a flow rate of 1 mL min⁻¹. The UV detector wavelength was set at 221 nm. Fifteen minutes after the administration, the gastrodin reached the peak concentration in brain and bile. In addition, the results indicate that gastrodin penetrates the blood-brain barrier (BBB) and goes through hepatobiliary excretion.     

Adsorption and reactions of NO on clean and CO-precovered Ir(111)

Adsorption and reactions of NO on clean and CO-precovered Ir(111) were investigated by means of X-ray photoelectron spectroscopy (XPS), high-resolution electron energy loss spectroscopy (HR-EELS), infrared reflection absorption spectroscopy (IRAS), and temperature-programmed desorption (TPD). Two NO adsorption states, indicative of fcc-hollow sites and atop sites, were present on the Ir(111) surface at saturation coverage. NO adsorbed on hollow sites dissociated to Na and Oa at temperatures above 283 K. The dissociated Na desorbed to form N2 by recombination of Na at 574 K and by a disproportionation reaction between atop-NO and Na at 471 K. Preadsorbed CO inhibited the adsorption of NO on atop sites, whereas adsorption on hollow sites was not affected by the coexistence of CO. The adsorbed CO reacted with dissociated Oa and desorbed as CO2 at 574 K.     

Why are viscosities lower for ionic liquids with -CH2Si(CH3)3 vs -CH2C(CH3)3 substitutions on the imidazolium cations?

We have prepared novel room temperature ionic liquids (RTILs) with trimethylsilylmethyl (TMSiM)-substituted imidazolium cations and compared the properties of these liquids with those for which the TMSiM group is replaced by the analogous neopentyl group. The ionic liquids are prepared with both tetrafluoroborate (BF(4)(-)) and bis(trifluoromethylsulfonyl)imide (NTf(2)(-)) anions paired with the imidazolium cations. At 22 degrees C, the TMSiM-substituted imidazolium ILs have shear viscosities that are reduced by a factor of 1.6 and 7.4 relative to the alkylimidazolium ILs for the NTf(2)(-) and BF(4)(-) anions, respectively. To understand the effect of silicon substitution on the viscosity, the charge densities have been calculated by using density functional theory electronic structure calculations. The ultrafast intermolecular, vibrational, and orientational dynamics of these RTILs have been measured by using femtosecond optical heterodyne-detected Raman-induced Kerr effect spectroscopy (OHD-RIKES). The intermolecular dynamical spectrum provides an estimate of the strength of interactions between the ions in the RTILs, and provides a qualitative explanation for the observed reduction in viscosity for the silicon-substituted RTILs.     

Stability of atomic oxygen chemisorption on Pt‐alloy surfaces

A density functional theory calculation is used to investigate the atomic oxygen (O) stability over platinum (Pt) and Pt‐based alloy surfaces. Here, the stability is connected with the preferential adsorption sites for O chemisorptions and the adsorption energy. Thus, the interaction mechanism between atomic O and metal surfaces is studied by using charge transfer analysis. In this present paper, atomic structure and binding energy of oxygen adsorption on the Pt(111) are in a very good agreement with experiment and previous density functional theory calculations. Furthermore, we obtained that the addition of ruthenium (Ru) and molybdenum (Mo) on the pure Pt surface enhances the adsorption energy. Our charge transfer analysis shows that the largest charge transfer contributing to the metal‐O bonding formation is observed in the case of O/PtRuMo surface followed by O/PtRu surface. This is in consistency with metal d‐orbital characteristic, where Mo has much more empty d‐orbital than Ru in correspondence to accept electrons from atomic oxygen. Copyright © 2016 John Wiley & Sons, Ltd.     

Officinalioside,a new lignan glucoside from Borago officinalis L.

A new lignan glucoside, officinalioside (1), was isolated from n-BuOH fraction of the aerial parts of Borago officinalis L., together with four known compounds: actinidioionoside (2), roseoside (3), crotalionoside C (4) and kaempferol 3-O-β-D-galactopyranoside (5). The structure of the new compound was established by means of spectroscopic and chemical analyses. Compounds 1 and 2 showed a moderate DPPH radical scavenging activity (IC₅₀: 52.6 ± 1.70 and 41.3 ± 0.25 μM, respectively) comparable with that of the standard trolox (16.6 ± 2.2 μM) without any significant cytotoxicity towards human cell line A549 (IC₅₀ > 100 μM).     

An iterative type I polyketide synthase PKSN catalyzes synthesis of the decaketide alternapyrone with regio-specific octa-methylation

A biosynthetic gene cluster containing five genes, alt1-5, was cloned from Alternaria solani, a causal fungus of early blight disease to tomato and potato. Homology searching indicated that the alt1, 2, and 3 genes code for cytochrome P450s and the alt4 gene for a FAD-dependent oxygenase/oxidase. The alt5 gene encodes a polyketide synthase (PKS), named PKSN, that was found to be an iterative type I complex reduced-type PKS with a C-methyltransferase domain. To identify the PKSN function, the alt5 gene was introduced into the fungal host Aspergillus oryzae under an alpha-amylase promoter. The transformant produced a polyketide compound, named alternapyrone, whose structure is shown to be 3,5-dimethyl-4-hydroxy-6-(1,3,5,7,11,13-hexamethyl-3,5,11-pentadecatrienyl)-pyran-2-one. Labeling experiments confirmed that alternapyrone is a decaketide with octa-methylation from methionine on every C(2) unit except the third unit.     

An accurate numerical multicenter integration for molecular orbital theory

A powerful and accurate numerical three‐dimensional integration scheme was developed especially for molecular orbital calculations. A multicenter integral is decomposed into the sum of single‐center integrals using nuclear weight functions and calculated using Gaussian quadrature rules. The decomposed single‐center integrands show strong anisotropy. With a careful selection of the Gaussian quadrature rule according to the anisotropy, it is possible to obtain an accuracy of 13 digits with a small number of integration points for the overlap integrals, normalization integrals, and molecular integrals for the hydrogen molecule. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 72: 509–523, 1999     

Staphylionosides A-K: megastigmane glucosides from the leaves of Staphylea bumalda DC

Chemical investigation of leaves of Staphylea bumalda DC., collected in the suburbs of Hiroshima City, afforded 11 new megastigmane glucosides, named staphylionosides A-K (3-13), along with two known megastigmane glucosides (1, 2). The relative structures were elucidated from spectroscopic evidence, and the absolute structures of the aglycones were determined by means of the combination of beta-D-glucosylation-induced shift-trends and the modified Mosher's method.