Derivation of generalized Young’s equation for cylindrical droplets between the outer surfaces of two tangent cylinders

The wetting properties of cylindrical droplets between the outer surfaces of two tangent cylinders are investigated by means of thermodynamics. For the three-phase system containing solid, liquid and vapor phases, a generalized Young equation for contact angles of cylindrical drops between the outer surfaces of two tangent cylinders has been thermodynamically derived. In fact, the theoretical foundation of the derived generalized Young’s equation is based on Gibbs’s capillary phenomena and the method of Rusanov’s dividing line

Research of the active reflector antenna using laser angle metrology system

Active reflector is one of the key technologies for constructing large telescopes, especially for the millimeter/sub-millimeter radio telescopes. This article introduces a new efficient laser angle metrology system for the active reflector antenna of the large radio telescopes, with a plenty of active reflector experiments mainly about the detecting precisions and the maintaining of the surface shape in real time, on the 65-meter radio telescope prototype constructed by Nanjing Institute of Astronomical Optics and Technology (NIAOT). The test results indicate that the accuracy of the surface shape segmenting and maintaining is up to micron dimension, and the time-response can be of the order of minutes. Therefore, it is proved to be workable for the sub-millimeter radio telescopes.Comment: 10 pages, 15 figure

Single-step bioconversion of lignocellulose to hydrogen using novel moderately thermophilic bacteria

BACKGROUND: Consolidated bioprocessing (CBP) of lignocellulosic biomass to hydrogen offers great potential for lower cost and higher efficiency compared to processes featuring dedicated cellulase production. Current studies on CBP-based hydrogen production mainly focus on using the thermophilic cellulolytic bacterium Clostridium thermocellum and the extremely thermophilic cellulolytic bacterium Caldicellulosiruptor saccharolyticus. However, no studies have demonstrated that the strains in the genus Thermoanaerobacterium could be used as the sole microorganism to accomplish both cellulose degradation and H(2) generation. RESULTS: We have specifically screened for moderately thermophilic cellulolytic bacteria enabling to produce hydrogen directly from conversion of lignocellulosic materials. Three new strains of thermophilic cellulolytic bacteria in the genus Thermoanaerobacterium growing at a temperature of 60°C were isolated. All of them grew well on various plant polymers including microcrystalline cellulose, filter paper, xylan, glucose, and xylose. In particular, the isolated bacterium, designated as Thermoanaerobacterium thermosaccharolyticum M18, showed high cellulolytic activity and a high yield of H(2). When it was grown in 0.5% microcrystalline cellulose, approximately 82% cellulose was consumed, and the H(2) yield and maximum production rate reached 10.86 mmol/g Avicel and 2.05 mmol/L/h, respectively. Natural lignocellulosic materials without any physicochemical or biological pretreatment also supported appreciable growth of strain M18, which resulted in 56.07% to 62.71% of insoluble cellulose and hemicellulose polymer degradation in corn cob, corn stalk, and wheat straw with a yield of 3.23 to 3.48 mmol H(2)/g substrate and an average production rate of 0.10 to 0.13 mmol H(2)/L/h. CONCLUSIONS: The newly isolated strain T. thermosaccharolyticum M18 displayed effective degradation of lignocellulose and produced large amounts of hydrogen. This is the first report of a Thermoanaerobacterium species presenting cellulolytic characteristics, and this species thus represents a novel cellulolytic bacterium distinguished from all other known cellulolytic bacteria. In comparison, the extraordinary yield and specific rate of hydrogen for strain M18 obtained from lignocellulose make it more attractive in monoculture fermentation. T. thermosaccharolyticum M18 is thus a potential candidate for rapid conversion of lignocellulose to biohydrogen in a single step

N-(2-Hydroxy­ethyl)-1,8-naphthalimide

In the mol­ecule of the title compound, C14H11NO3, the naphthalimide ring system is nearly planar (r.m.s. deviation 0.0139 Å). In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into centrosymmetric dimers forming R 2 2(14) ring motifs. π–π contacts between the naphthalimide rings [centroid–centroid distances = 3.648 (3), 3.783 (3), 3.635 (3), 3.722 (3) and 3.755 (3) Å] may further stabilize the structure

Determination of tetramethylpyrazine in rat plasma by liquid chromatography/electrospray mass spectrometry

A sensitive and selective liquid chromatography/electrospray mass spectrometry (LC-ESIMS) method for determination of tetramethylpyrazine in rat plasma was developed. After addition of phenacetin as internal standard, protein precipitation by acetonitrile was used as sample preparation. Chromatographic separation was achieved on a Zorbax SB-C18 (2.1 mm×150 mm, 5 µm) column with (40:60, v/v) acetonitrile-water containing 0.1 % formic acid as mobile phase. Electrospray ionization (ESI) source was applied and operated in positive ion mode; selected ion monitoring (SIM) mode was used to quantify tetramethylpyrazine using target fragment ions m/z 136.9 for tetramethylpyrazine and m/z 179.8 for the IS. Calibration plots were linear over the range of 20-4000 ng/mL for tetramethylpyrazine in plasma. Lower limit of quantitation (LLOQ) for tetramethylpyrazine was 20 ng/mL. Mean recovery of tetramethylpyrazine from plasma was in the range 95.4-97.2 %. RSD of intra-day and inter-day precision were less than 9 %, respectively. This method is simple, sensitive and fast enough to be used in pharmacokinetic research for determination of tetramethylpyrazine in rat plasma.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Determination of tetramethylpyrazine in rat plasma by liquid chromatography/electrospray mass spectrometry

A sensitive and selective liquid chromatography/electrospray mass spectrometry (LC-ESIMS) method for determination of tetramethylpyrazine in rat plasma was developed. After addition of phenacetin as internal standard, protein precipitation by acetonitrile was used as sample preparation. Chromatographic separation was achieved on a Zorbax SB-C18 (2.1 mm×150 mm, 5 µm) column with (40:60, v/v) acetonitrile-water containing 0.1 % formic acid as mobile phase. Electrospray ionization (ESI) source was applied and operated in positive ion mode; selected ion monitoring (SIM) mode was used to quantify tetramethylpyrazine using target fragment ions m/z 136.9 for tetramethylpyrazine and m/z 179.8 for the IS. Calibration plots were linear over the range of 20-4000 ng/mL for tetramethylpyrazine in plasma. Lower limit of quantitation (LLOQ) for tetramethylpyrazine was 20 ng/mL. Mean recovery of tetramethylpyrazine from plasma was in the range 95.4-97.2 %. RSD of intra-day and inter-day precision were less than 9 %, respectively. This method is simple, sensitive and fast enough to be used in pharmacokinetic research for determination of tetramethylpyrazine in rat plasma.Colegio de Farmacéuticos de la Provincia de Buenos Aire

(R)-7-Bromo-2,3,4,4a-tetra­hydro-1H-xanthen-1-one

The title compound, C13H11BrO2, contains a tricyclic ring system with one chiral center which exhibits an R configuration. The crystal structure is devoid of any classical hydrogen bonding

4-Bromo-2,6-dimethyl­anilinium bromide monohydrate

In the title compound, C8H11BrN+·Br−·H2O, a network of N—H⋯O, N—H⋯Br and O—H⋯Br hydrogen bonds helps to consolidate the crystal packing