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861.
Stéphanie Frantz Monika Sieger Ingo Hartenbach Falk Lissner Thomas Schleid Jan Fiedler Carole Duboc Wolfgang Kaim 《Journal of organometallic chemistry》2009,694(7-8):1122-1133
Attempts to prepare and study the title complexes yielded the structurally characterized neutral compounds anti-{(μ-abpy)[Re(CO)3X]2}, X = Br (I41/a), I (C2/c), and two crystalline forms of anti-{(μ-abpy)[Re(CO)3Cl]2}. One of these forms (P21/c) has been reported before, the other (I41/a), obtained through crystallization in the presence of Zn, is isostructural to the form found for anti-{(μ-abpy)[Re(CO)3Br]2}. Syntheses of {(μ-abpy)[Re(CO)3Cl]2} at high or low temperatures yielded different compositions, the high temperature procedure led to partial formation of syn/anti mixtures and one-electron reduced species. The same was observed to a greater extent in the preparation of labile syn/anti-{(μ-abpy)[Re(CO)3F]2}o/??. The identity of isolated species was investigated using 1H NMR spectroscopy, variable frequency EPR spectroscopy, cyclic voltammetry, UV/Vis- and IR-spectroelectrochemistry. The effects of halide variation on structure, reduction potentials, isomerism and electronic situation are being discussed. 相似文献
862.
Density measurements are reported performed on three 1-alkyl-3-methylimidazolium-based ([Cn-mim], n=2,4,6) ionic liquids with tetrafluoroborate anion at atmospheric pressure at 15 temperatures from 281 to 353 K. The buoyancy method was employed, using the microbalance of the Krüss K100MK2 tensiometer. At each temperature from 33 to 55 individual buoyancy readings were taken in most cases. The density average values at particular temperatures are presented with estimated total standard uncertainty less than ±0.4 kg m−3 (3.3 ×10−4?). An empirical density–temperature equations have been developed describing the temperature dependence of each ionic liquid density. The 58 new experimental data points on the density–temperature relation of the three ionic liquids of interest are means calculated from about 3000 individual density readings, which have been altogether taken in the present study. 相似文献
863.
Östreicher Christiane Gensberger-Reigl Sabrina Pischetsrieder Monika 《Analytical and bioanalytical chemistry》2019,411(6):1273-1286
Analytical and Bioanalytical Chemistry - The Nrf2 signaling pathway is highly significant for redox homeostasis. Hence, nutrients and drugs activating Nrf2 can prevent oxidative stress-mediated... 相似文献
864.
Pol Karier Felix Ungeheuer Andreas Ahlers Felix Anderl Christian Wille Alois Fürstner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(1):254-259
The new approach to the anticancer agent rhizoxin D described herein does not cohere with the conventional logic of metathesis, according to which macrocycles are best closed at a disubstituted olefinic site; rather, the trisubstituted C11?C12 alkene flanked by an allylic ‐OH group served as the pivot point for synthesis. This motif was attained in good yield and excellent selectivity by a sequence of alkyne metathesis, trans‐hydrostannation and cross coupling. Because the exact same substructure is prominently featured in numerous other natural products, the underpinning strategy, though unusual, might bear more general relevance. 相似文献
865.
In the first part of this paper a universal fluid velocity based algorithm for simulating hydraulic fracture with leak-off was created for a penny-shaped crack. The power-law rheological model of fluid was assumed and the final scheme was capable of tackling both the viscosity and toughness dominated regimes of crack propagation. The obtained solutions were shown to achieve a high level of accuracy. In this paper simple, accurate, semi-analytical approximations of the solution are provided for the zero leak-off case, for a wide range of values of the material toughness and parameters defining the fluid rheology. A comparison with other results available in the literature is undertaken. 相似文献
866.
Tomas Jasenovec Dominika Radosinska Marta Kollarova Peter Balis Kristina Ferenczyova Barbora Kalocayova Monika Bartekova Lubomira Tothova Jana Radosinska 《Molecules (Basel, Switzerland)》2021,26(16)
Diabetes mellitus is characterized by tissue oxidative damage and impaired microcirculation, as well as worsened erythrocyte properties. Measurements of erythrocyte deformability together with determination of nitric oxide (NO) production and osmotic resistance were used for the characterization of erythrocyte functionality in lean (control) and obese Zucker diabetic fatty (ZDF) rats of two age categories. Obese ZDF rats correspond to prediabetic (younger) and diabetic (older) animals. As antioxidants were suggested to protect erythrocytes, we also investigated the potential effect of quercetin (20 mg/kg/day for 6 weeks). Erythrocyte deformability was determined by the filtration method and NO production using DAF-2DA fluorescence. For erythrocyte osmotic resistance, we used hemolytic assay. Erythrocyte deformability and NO production deteriorated during aging—both were lower in older ZDF rats than in younger ones. Three-way ANOVA indicates improved erythrocyte deformability after quercetin treatment in older obese ZDF rats only, as it was not modified or deteriorated in both (lean and obese) younger and older lean animals. NO production by erythrocytes increased post treatment in all experimental groups. Our study indicates the potential benefit of quercetin treatment on erythrocyte properties in condition of diabetes mellitus. In addition, our results suggest potential age-dependency of quercetin effects in diabetes that deserve additional research. 相似文献
867.
M. P. Danilaev E. A. Bogoslov Yu. E. Pol’skii A. R. Nasybullin M. S. Pudovkin A. R. Khadiev 《Technical Physics》2017,62(2):255-260
The influence of growth conditions on the carbon dendrite structure has been investigated. The threshold values of the ratio between electron temperature T e and kinetic temperature T of the gas near a needle electrode and of the discharge current density, which are necessary for dendritic growth, have been determined. It has been shown that the hexagonal structure of submicron carbon particles arises when a number of hydrocarbons are used to synthesize dendrites. It has been found that the degree of order in the carbon structure can be controlled by applying external actions at the stage of graphite particle nucleation. The characteristic frequencies of inertial actions that may be energetically appropriate must exceed 10 kHz. 相似文献
868.
The aim of this study was to determine the reference value of pH in healthy women and men using the phosphorus magnetic resonance spectroscopy technique. The brains of 65 young volunteers were examined. The intracellular pH was calculated in the group of women and the group of men. In both groups, the average pH was slightly alkaline (respectively 7.10?±?0.08 and 7.08?±?0.12). No statistically significant sex difference in brain pH was found. Thus, in case if this method is used to estimate possible brain pathology in the young population, it is not needed to take the gender factor into consideration. 相似文献
869.
Aleksandra Deptuch Teresa Jaworska-Gołąb Monika Marzec Jakub Fitas Keigo Nagao Janusz Chruściel 《Phase Transitions》2017,90(8):765-772
ABSTRACTProperties of 4-n-pentylphenyl-4’-n-octyloxythiobenzoate (8OS5), belonging to the nOS5 homologous series, have been studied by complementary methods. The phase sequence, the phase transition temperatures, the thickness of molecular layers, the average distance between long axes of molecules and the correlation length were determined during cooling and heating. For the first time, simultaneous X-ray diffraction and differential scanning calorimetry measurements have been used to study mesomorphic properties. The results are compared with the ones obtained in standard measurements by means of differential scanning calorimetry, X-ray diffraction and polarizing optical microscopy. Meaning of experimental procedures applied in investigations of monotropic mesophases below a melting point is discussed. 相似文献
870.
Manjari Bagchi Jishnu Dey Mira Dey Taparati Gangopadhyay Sibasish Laha Subharthi Ray Monika Sinha 《Physics letters. [Part B]》2008
High energy density (?) and temperature (T) links general relativity and hydrodynamics leading to a lower bound for the ratio of shear viscosity (η) and entropy density (s ). We get the interesting result that the bound is saturated in the simple model for quark matter that we use for strange stars at the surface for T∼80 MeV. At this T we have the possibility of cosmic separation of phases. At the surface of the star where the pressure is zero—the density ? has a fixed value for all stars of various masses with correspondingly varying central energy density ?c. Inside the star where this density is higher, the ratio of η/s is larger and are like the known results found for perturbative QCD. This serves as a check of our calculation. The deconfined quarks at the surface of the strange star at T=80 MeV seem to constitute the most perfect interacting fluid permitted by nature. 相似文献