Real-time detection technique for Doppler optical coherence tomography

We propose and demonstrate a novel detection technique, based on a modified electronic phase-locked loop, for Doppler optical coherence tomography. The technique permits real-time simultaneous reflectivity and continuous, bidirectional velocity mapping in turbid media over a wide velocity range with minimal sensitivity penalty compared with conventional optical coherence tomography, which is a major advance over current postprocessing and discrete parallel detection techniques.     

A spectroscopic and computational investigation of the vanadomolybdate local structure in the lyonsite phase Mg(2.5)VMoO(8)

The vibrational spectrum of Mg2.5VMoO8 obtained by quantum mechanical simulation is compared with the experimentally observed Raman spectrum. This simulation suggests that the observed band at 1016 cm(-1) is attributed to the Mo=O-Mg stretching from two-coordinate oxygen atoms that are adjacent to Mg2+ cation vacancies. Extended X-ray absorption fine structure spectroscopy supports the structural model used to simulate the vibrational modes in Mg2.5VMoO8 that match the observed Raman data.     

Is There a Novel Biosynthetic Pathway in Mice That Converts Alcohol to Dopamine,Norepinephrine and Epinephrine?

Previous studies in animals and humans have shown multiple types of interaction between alcohol (ethanol) intake and the catecholamine signaling molecules: dopamine, norepinephrine and epinephrine. This literature suggests that the administration of alcohol to rodents affects the central and peripheral (blood plasma) levels of these catecholamines. Two prior publications (Fitzgerald 2012, 2020) put forth the hypothesis that there may be a currently unidentified biosynthetic pathway, in a range of organisms, that actually converts alcohol to dopamine, norepinephrine and epinephrine. This publication describes the details for how to test this hypothesis in mice. Mice can be systemically injected with an intoxicating dose of commercially available stable isotope-labeled ethanol (ethanol-1-¹³C), and blood plasma samples and brains can be collected approximately two to 24 h post-injection. Liquid chromatography-mass spectrometry analysis can then be used to test whether some of the labeled ethanol molecules have been incorporated into new dopamine, norepinephrine, and epinephrine molecules, in plasma and brain samples. If confirmed, this hypothesis may have broadly reaching implications both for basic neuroscience and our understanding of alcohol abuse and alcoholism.     

Barium

Ohne Zusammenfassung     

STUDIES DIRECTED TOWARD THE SYNTHESIS OF NAKADOMARIN A

The application of a Pummerer-initiated tandem reaction cascade leads to the highly stereoselective formation of the tetracyclic core of nakadomarin A.     

The one-electron oxidation of [HCCOCC]- to form neutral HCCOCC, and the subsequent rearrangement of HCCOCC to form HCCCCO. An experimental and computational study

The singlet anion [HCCOCC]- may be made in the source of a VG ZAB 2HF mass spectrometer by the reaction between F- (from SF6) and H-C[triple chemical bond]C-O-C[triple chemical bond]C-TMS. Vertical (Franck-Condon) one-electron oxidation of [HCCOCC]- in the first collision cell produces doublet neutral HCCOCC. A combination of experiment and molecular modelling [at the CCSD(T)/aug-cc-pVDZ//B3LYP/6-31 + G(d) level of theory] provides data which are consistent with some HCCOCC neutrals being stable for the duration of the neutralisation reionisation experiment, while others rearrange to form the decomposing doublet neutral HCCCCO.     

Determination of volatile mercury species at the picogram level by low-temperature gas chromatography with cold-vapour atomic fluorescence detection

Alkylmercury compounds were preconcentrated from air on a Carbotrap (graphitized carbon black) column at room temperature. The species were then transferred by thermal desorption to a U-tube chromatographic column packed with 15% OV-3 on Chromosorb WAW-DMSC, held at ?196°C in liquid nitrogen. The compounds were clearly separated and eluted in order of increasing polarity using a simple, ramped heating step to 180°C over 20 min. After thermal decomposition of the eluant, the resultant mercury vapour was detected by cold-vapour atomic fluorescence spectrometry. The detection limits (as Hg) for the system were approximately 0.3 pg for mercury and dimethylmercury, 0.4 pg for diethylmercury, and 2.0 pg for methylmercury chloride. A study of the Long Island Sound atmosphere showed Hg⁰ to account for 95–100% of the total mercury present, with the remainder being monomethylmercury.     

Anisotropic ferromagnetism in substituted zinc oxide

Room-temperature ferromagnetism is observed in (110) oriented ZnO films made from targets containing 5 at. % of Sc, Ti, V, Fe, Co, or Ni, but not Cr, Mn, or Cu ions. There are large moments, 2.6 micro(B) and 0.5 micro(B)/dopant atom for Co- and Ti-containing oxides, respectively. There is also a moment of 0.3 micro(B)/Sc. Magnetization is very anisotropic, with variations of up to a factor of 3 depending on the orientation of the applied field relative to the substrate. Results are interpreted in terms of a spin-split donor impurity-band model, which can account for ferromagnetism in insulating or conducting high-k oxides with concentrations of magnetic ions that lie far below the percolation threshold. Magnetic moments are associated with two-electron defects in the films as well as unpaired electrons of the 3d ions.     

The formation of the stable radicals .CH2CN, CH3.CHCN and .CH2CH2CN from the anions -CH2CN, CH3-CHCN and -CH2CH2CN in the gas phase. A joint experimental and theoretical study

Franck-Condon one-electron oxidation of the stable anions -CH2CN, CH3-CHCN and -CH2CH2CN (in the collision cell of a reverse-sector mass spectrometer) produce the radicals .CH2CN, CH3.CHCN and .CH2CH2CN, which neither rearrange nor decompose during the microsecond duration of the neutralisation-reionisation experiment. Acetonitrile (CH3CN) and propionitrile (CH3CH2CN) are known interstellar molecules and radical abstraction of these could produce energised .CH2CN and CH3.CHCN, which might react with NH2. (a known interstellar radical) on interstellar dust or ice surfaces to form NH2CH2CN and NH2CH(CH3)CN, precursors of the amino acids glycine and alanine.