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Results 401 - 450 of 3046
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Li Jian Jun - - 2009
Remote control of the vent/detector split flow ratio in packed column supercritical fluid chromatography (pSFC) with flame ionization detector (FID) is demonstrated using a dual heated restrictor method. Restrictors stemming from a Tee at the separation column outlet were, respectively, fixed into an FID and a vent port, and their ...
Hong Xinguo - - 2009
We describe an approach for acquiring high quality x-ray absorption fine structure (XAFS) spectroscopy spectra with wide energy range at high pressure using diamond anvil cell (DAC). Overcoming the serious interference of diamond Bragg peaks is essential for combining XAFS and DAC techniques in high pressure research, yet an effective ...
Grauwet Tara - - 2009
The potential of Bacillus subtilis alpha-amylase (BSA) as a pressure-temperature-time indicator (pTTI) for high pressure pasteurization processing (400-600 MPa; T(i) 10-40 degrees C; 1-15 min) was investigated. A stepwise approach was followed for the development of an enzyme-based, extrinsic, isolated pTTI. First, based on literature data on the pressure stability, ...
Grove Stephen F - - 2009
High pressure processing (HPP) inactivation data were obtained for hepatitis A virus (HAV) suspended in buffered growth medium containing salt at either 15 or 30 g/liter. Pressures between 300 and 500 MPa were applied for treatment times of 60 to 600 s. In medium containing 15 g/liter salt, the HAV ...
Funfschilling Denis - - 2009
Measurements of the Nusselt number Nu and of temperature variations DeltaTb in the bulk fluid are reported for turbulent Rayleigh-Bénard convection of a cylindrical sample. They cover the Rayleigh-number range 10(9) less than or similar to Ra less than or similar to 3x10(14) using He (Prandtl number Pr=0.67), N2 (Pr=0.72) ...
Preciado Jessica A - - 2010
Isochoric (constant volume) preservation is an alternative to traditional cryopreservation methods because it requires less cryoprotectant and is simple to operate. In order to validate that this method automatically minimizes the pressure for a given temperature, pressure and temperature data were collected from a specially designed pressure vessel. This vessel ...
Markfort Corey D - - 2009
Dissolved oxygen (DO) is probably the most important parameter related to water quality and biological habitat in aquatic environments. In situ DO sensors are some of the most valuable tools used by scientists and engineers for the evaluation of water quality in aquatic ecosystems. Presently, we cannot accurately measure DO ...
Miyoshi Akira - - 2009
The product branching fractions for the reaction of atomic oxygen with ethene, O((3)P) + C(2)H(4)--> CH(3) + HCO (1a), --> H + CH(2)CHO (1b), --> H(2) + CH(2)CO (1c), have been investigated at room temperature (295 +/- 4 K) and pressures from 1 to 4 Torr (with N(2) or He ...
Spain David - - 2009
In classical flow through permeable rock, the pressure drop is linearly distributed through the medium. Shear induced structure materials, surfactant/co-solute pairs, were added to retard flow in higher permeability rock samples. A novel core holder allows the axial pressure distribution along the flow direction to be measured. This enables the ...
Guo Jian - - 2010
The Hulunbir grassland experienced aeolian desertification expansion during 1975-2000, but local rehabilitation during 2000-2006. Northern China suffered severe aeolian desertification during the past 50 years. Hulunbir grassland, the best stockbreeding base in Northern China, was also affected by aeolian desertification. To evaluate the evolution and status of aeolian desertification, as ...
Grinn-Gofro? Agnieszka - - 2009
A study was made of the link between time of day, weather variables and the hourly content of certain fungal spores in the atmosphere of the city of Szczecin, Poland, in 2004-2007. Sampling was carried out with a Lanzoni 7-day-recording spore trap. The spores analysed belonged to the taxa Alternaria ...
Medvedev S - - 2009
The discovery of new high-temperature superconductors based on FeAs has led to a new 'gold rush' in high-T(C) superconductivity. All of the new superconductors share the same common structural motif of FeAs layers and reach T(C) values up to 55 K (ref. 2). Recently, superconductivity has been reported in FeSe ...
Ding Yang - - 2009
Low temperature Mn K-edge x-ray magnetic circular dichroism and x-ray diffraction measurements were carried out to investigate the stability of the ferromagnetic ground state in manganite La0.75Ca0.25MnO3 under nearly uniform compression using diamond anvil cells. The magnetic dichroism signal gradually decreases with pressure and disappears at 23 GPa, and meanwhile ...
Winterrose M L - - 2009
Synchrotron x-ray diffraction (XRD) measurements, nuclear forward scattering (NFS) measurements, and density functional theory (DFT) calculations were performed on L1_{2}-ordered Pd3Fe. Measurements were performed at 300 K at pressures up to 33 GPa, and at 7 GPa at temperatures up to 650 K. The NFS revealed a collapse of the ...
Wosylus Aron - - 2009
The synthesis of the new binary Cs(8-x)Si(46) (shown here) completes the series of binary alkali metal silicides with a clathrate-I structure M(8-x)Si(46) (M = Na, K, Rb, Cs). In contrast with the lighter homologues, Cs(8-x)Si(46) can be prepared only at elevated pressures. The compound was obtained at 1200 degrees C ...
Ballerini Eleonora - - 2009
Diels-Alder cycloaddition reactions of 3-cyanocoumarin, hydroxy-substituted 3-cyanocoumarins and mesyl-substituted 3-cyano-coumarins with methyl-1,3-butadienes carried out under high pressure (11 kbar) are reported. Activation by high pressure allows these reactions to proceed satisfactorily under mild conditions to produce 6a-cyano-hydroxy- and 6a-cyano-mesyl-tetrahydro-6H-benzo[c]chromen-6-ones in moderate to excellent yield. The synthesis of cis-1-hydroxy-9-methyl-3-pentyl-6a,7,10,10a-tetrahydro-benzo[c]chromen-6-one as precursor ...
Itaya Megumi - - 2009
We measured the 13C-NMR spectrum and T1 of the quasi-two-dimensional organic superconductor kappa-(BEDT-TTF)2Cu(NCS)_{2} under pressure. This material was thought to show a relationship between T_{c} and the effective cyclotron mass m_{c};{*}, obtained from the Shubnikov-de Haas (SdH) effect. We found that kappa-(BEDT-TTF)2Cu(NCS)_{2} behaved as a Fermi liquid at low temperature ...
Aertsen Abram - - 2009
Pressure is a thermodynamic parameter whose unique effects on biological systems are increasingly being studied in a growing number of scientific fields. As such, the effects of high pressure are currently being investigated at different levels, ranging from proteins, enzymes and viruses to microorganisms, mammalian cells and tissues. Together with ...
Baek S-H - - 2009
We report 75As NMR measurements in CaFe2As2, made under applied pressures up to 0.83 GPa produced by a standard clamp pressure cell. Our data reveal phase segregation of paramagnetic and antiferromagnetic (AFM) phases over a range of pressures, with the AFM phase more than 90% dominant at low temperatures. In ...
Brodie Jedediah F - - 2009
Myriad tropical vertebrates are threatened by overharvest. Whether this harvest has indirect effects on nonhunted organisms that interact with the game species is a critical question. Many tropical birds and mammals disperse seeds. Their overhunting in forests can cause zoochorous trees to suffer from reduced seed dispersal. Yet how these ...
Katsaros G I - - 2009
The effect of high hydrostatic pressure (HHP) (100 to 700 MPa) combined with temperature (20 to 40 degrees C) on the activity of 5 aminopeptidases (PepN, PepX, PepY, PepC, and PepA) of Lactobacillus delbrueckii ssp. bulgaricus ACA-DC 0105, used as starter culture for feta cheese production, was studied. Aminopeptidases PepN, ...
Montoya Carolina Villegas - - 2009
With advantageous biomechanical properties, materials derived from ex vivo tissues are being actively investigated as scaffolds for tissue engineering applications. However, decellularization treatments are required before implantation to reduce the materials immune impact. The aim of these investigations was to assess a convective flow model as an enhanced methodology to ...
Dumont Charles - - 2009
Biomolecules are highly pressure-sensitive, but their dynamics upon return to ambient pressure are often too fast to observe with existing approaches. We describe a sample-efficient method capable of large and very fast pressure drops (<1 nanomole, >2,500 atmospheres and <0.7 microseconds). We validated the method by fluorescence-detected refolding of a ...
Wondraczek Lothar - - 2009
Differential scanning calorimetry and density measurements were employed to study relaxation processes in compressed NaAlSi(3)O(8) and Na(0.34)Ca(0.31)Al(0.96)Si(3.04)O(8) glasses with negative dependence of viscosity (eta) on pressure (p). Isobaric configurational heat capacities, coefficients of thermal expansion and compressibility of the melts, and real and apparent fictive temperatures are reported for the ...
Tkachev Sergey N - - 2009
The behavior of cyclopentane with pressure has been investigated to 21.5 GPa using Raman spectroscopy. Various phases were observed with pressure which included liquid, two plastic, and one true crystalline phases of cyclopentane during compression and decompression sequences. Optimized molecular structure and Raman and IR vibrational spectra of the most ...
Pudney Christopher R - - 2009
Mutation of an active-site residue in morphinone reductase leads to a conformationally rich landscape that enhances the rate of hydride transfer from NADH to FMN at standard pressure (1 bar). Increasing the pressure causes interconversion between different conformational substates in the mutant enzyme. While high pressure reduces the donor-acceptor distance ...
Sun Jian - - 2009
High-pressure structural transformations of carbon at terapascal pressures are studied using metadynamics and ab initio methods. Diamond transforms to a mechanically stable cubic structure (P4(1)32) at 2.5 TPa and 300 K. At 4000 K and 2 TPa, simple cubic carbon SC1 (Pm-3m) is obtained from cubic diamond. The high-pressure tetrahedrally ...
Glascoe Elizabeth A - - 2009
The time scale and/or products of photoinduced decomposition of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) were investigated at ambient pressure and compared with products formed at 8 GPa. Ultrafast time-resolved infrared and steady-state Fourier transform IR (FTIR) spectroscopies were used to probe TATB and its products after photoexcitation with a 5 ns pulse of ...
Caravati S - - 2009
Based on ab initio molecular dynamics simulations, we identify the atomistic mechanism of the pressure induced amorphization of Ge(2)Sb(2)Te(5). The simulations reveal that homopolar Ge/Sb bonds appear in cubic Ge(2)Sb(2)Te(5) under pressure, giving rise to square rings rotated by 45 degrees with respect to the crystalline axis whose formation is ...
Cui Hengbo - - 2009
A new organic conductor, (BEST)(2)InBr(4), with alternating donor layer arrangement has been synthesized, and the electrical properties have been investigated up to 10.8 GPa. The temperature dependence of the high-pressure resistivity shows a complicated metal-semiconductor transition behavior. The room temperature resistivity decreases with pressure up to 8.6 GPa but increases ...
Lodaite Kristina - - 2009
The effects of high-pressure homogenisation (HPH) in the pressure range 100-300 MPa on the gel formation and rheological properties of rennet-induced skim milk (0.08%, fat, w/w) and standardised milk (3.60% fat, w/w) gels at pH 6.60 were studied. The average casein micelle size in skim milk was significantly reduced and ...
Vinković Dejan - - 2009
Dusty disks around young stars are formed out of interstellar dust that consists of amorphous, submicrometre grains. Yet the grains found in comets and meteorites, and traced in the spectra of young stars, include large crystalline grains that must have undergone annealing or condensation at temperatures in excess of 1,000 ...
Su Lei - - 2009
Behavior of the phase transition of an ionic liquid, [Cn-mim][PF(6)], has been investigated under pressures up to 1.0 GPa by using a high-pressure differential thermal analysis (DTA) apparatus. The T versus P phase diagrams of [BMIM][PF(6)] and [EMIM][PF(6)] are constructed. The DTA curve of [BMIM][PF(6)] shows one endothermal valley in ...
Smith K - - 2009
The effects of pressure (400, 500 and 600 MPa), dwell time (1 and 5 min) and temperature (25 and 75 degrees C) on microbial quality and protein stability of soymilk during 28 days of storage (4 degrees C) were evaluated under aerobic and anaerobic conditions. After processing and during storage, ...
Debessai M - - 2009
Divalent Eu (4f;{7}, J=7/2) possesses a strong local magnetic moment which suppresses superconductivity. Under sufficient pressure it is anticipated that Eu will become trivalent (4f;{6}, J=0) and a weak Van Vleck paramagnet, thus opening the door for a possible superconducting state, in analogy with Am metal (5f;{6}, J=0) which superconducts ...
Cui Hengbo - - 2009
The four-probe electrical resistivity measurements on a single-component molecular semiconductor [Ni(ptdt)(2)] (Ni(S(8)C(9)H(6))(2)) was performed up to 20.7 GPa by using a diamond anvil cell. A newly improved method was employed to reduce the effect of uniaxial pressure. The semiconducting behavior persisted up to 17.9 GPa. The pressure-induced metallization began to ...
Rountree C L - - 2009
Amorphous silica density at ambient pressure is known to depend on thermal history (through the quenching rate) but also, at room temperature, on the maximum pressure applied in the past. Here we show that beyond density, a mechanical loading can endow the structure with an orientational order. Molecular dynamics simulations ...
Dix O M - - 2009
We measure the effect of uniaxial pressure on the superconducting transition temperature T_{c} in CeIrIn5. We find a linear change in T_{c} with both a-axis and c-axis pressure, with slopes of 56 and -66 mK/kbar, respectively. By comparing results from doping studies and different types of pressure measurements, we separate ...
Khelladi Hassina - - 2009
An experimental study of some assorted glycerol properties is carried out in order to determine, under high static pressure, the glycerol nonlinearity parameter B/A against temperature by a modified isentropic method. The static pressure and temperature ranges exploited in this experimental investigation, of various glycerol properties, are extended respectively from ...
Yafetto Levi - - 2009
Rhizomorphs of wood-decay basidiomycetes are root-like structures produced by the coordinated growth of thousands of hyphae. Very little is known about their development nor the way that they penetrate soils and rotting wood. In this study, we applied techniques used in previous studies on hyphae to explore the mechanics of ...
Hoijemberg Pablo A - - 2009
We studied the photolysis of (1-biphenyl-4-yl-1-methyl-ethyl)-tert-butyl diazene in supercritical CO(2) and Xe, as well as in compressed Kr. The compound has good solubility in the mentioned fluids, allowing the photolysis measurements to be performed in CO(2) at 1.4 K above T(c) and at pressures as low as 70 bar. We ...
Zarechnaya E Yu - - 2009
An orthorhombic (space group Pnnm) boron phase was synthesized at pressures above 9 GPa and high temperature, and it was demonstrated to be stable at least up to 30 GPa. The structure, determined by single-crystal x-ray diffraction, consists of B12 icosahedra and B2 dumbbells. The charge density distribution obtained from ...
Pedrini Luciano A - - 2009
BACKGROUND: Mid-dilution haemodiafiltration (MD-HDF), reported as a highly efficient convective-mixed technique, has demonstrated serious drawbacks in relation to the high pressure originating inside the blood compartment of the filter during clinical application. This randomized crossover design study was planned to optimize the efficiency of the MD-HDF technique while reducing its ...
Mandal Amritlal - - 2009
Optic nerve head astrocytes become abnormal in eyes that have elevated intraocular pressure, and cultured astrocytes display altered protein expression after being subjected for > or = 1 days to elevated hydrostatic pressure. Here we show that 2-h elevated hydrostatic pressure (15 or 30 mmHg) causes phosphorylation of ERK1/2, ribosomal ...
Lee Minhyea - - 2009
We report the observation of a highly unusual Hall current in the helical magnet MnSi in an applied pressure P=6-12 kbars. The Hall conductivity displays a distinctive stepwise field profile quite unlike any other Hall response observed in solids. We identify the origin of this Hall current with the effective ...
Wei Zhao-Jun - - 2009
Supercritical carbon dioxide extraction (SC-CO(2)) of oil from desilked silkworm pupae was performed. Response surface methodology (RSM) was applied to optimize the parameters of SC-CO(2) extraction. The effects of independent variables, including pressure, temperature, CO(2) flow rate, and extraction time, on the yield of oil were investigated. The statistical analysis ...
Mizunuma Mika - - 2009
We describe the effect of high pressure and high temperature on neuronal activity. Increased intracranial pressure is generally a pathological sign observed in intracerebral hemorrhage, brain edema, and brain tumor, yet little is known about how the hyperbaric pressure per se affects neuronal activity. Using a pressure/temperature-changeable perfusion chamber, we ...
Barrio Maria - - 2009
Temperatures and melting enthalpies of orthorhombic Phases I and II of natural progesterone, together with the temperature dependence of their lattice parameters and the specific volume of the melt at ordinary pressure, have been determined. With these results, a topological pressure-temperature (P-T) phase diagram accounting for the thermodynamic relationships between ...
Givan Uri - - 2009
Si((1-x))Ge(x) nanowires (NWs) constitute promising building blocks for future electronic and optoelectronic devices due to the enhanced tuneability of their physical properties, achieved mainly by controlling their chemical composition. In this study, the pressure dependence of the chemical composition, growth and tapering rates and crystalline structure of Si((1-x))Ge(x) NWs grown ...
Katifori Eleni - - 2009
Hydrostatically pressurized circular rings confined to two dimensions (or cylinders constrained to have only z -independent deformations) undergo Euler-type buckling when the outside pressure exceeds a critical value. We perform a stability analysis of rings with arclength-dependent bending moduli and determine how weakened bending modulus segments affect the buckling critical ...
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