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A fiber-array probe is designed to measure the damping behavior of a small perturbed shock wave in an opaque substance, by which the effective viscosity of substance under the condition of high temperature and high pressure can be constrained according to the flyer-impact technique. It shows that the measurement precision of the shock arrival time by using this technique is within 2 ns. To easily compare with the results given by electrical pin technique, the newly developed method is used to investigate the effective viscosity of aluminum (Al). The shear viscosity coefficient of Al is determined to be 1700 Pa·s at 71 GPa with a strain rate of 3.6 × 106 s−1, which is in good agreement with the results of other methods. The advantage of the new technique over the electrical pin one is that it is applicable for studying the non-conductive substances. [ABSTRACT FROM AUTHOR]

Combining a low temperature liquidizing system with a transient Raman spectroscopy, a new experimental technique is established for the first time on a two-stage light-gas gun, and it is employed to study shock-compressed fluid silane. With this experimental technique, we first obtain a Raman peak shift relating to the Si–H stretching vibration mode of molecular liquid silane under shock loading conditions. The Raman peak of 2184 cm−1 at an initial state of 0 GPa and 85 K moves to 2223.4 cm−1 at a shocked state of 10.5 GPa and 950 K, and its full width of half maximum broadens from 33 cm−1 to 118 cm−1. The shocked temperature, calculated by the thermodynamic equation of state, is well consistent with that estimated by the Doppler broadening function. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the effect of RNA interference (RNAi) on the inhibition of interleukin (IL)-6 expression in rat cerebral gliocytes in vitro and rat cerebral traumatic tissues in vivo, as well as the effect of RNAi on cerebral edema. pSUPER vectors containing IL-6 small hairpin RNA (pSUPER-IL-6 1-5) were designed, constructed and transfected into C6 rat glioma cells using cationic liposomes. ELISA was used to select the plasmid with the strongest interference effect. A freefall method was used to generate a rat brain injury model and rats were randomly divided into treatment, empty plasmid and control groups (n=14/group). IL-6 levels, water content and sodium content were determined in the brain tissues at 24 and 72 h post-injury. pSUPER-IL-6 was effectively transfected into C6 cells and was found to inhibit the expression of IL-6 rather than IL-8. The pSUPER-IL-6 1 vector was most effective in inducing RNAi. In vivo, IL-6 levels were observed to be lowest in the interference group and there were statistically significant differences in water and sodium content among the experimental groups (P<0.05). RNAi was found to inhibit IL-6 expression in vivo and in vitro in rat cerebral gliocytes, and the reduction of the IL-6 levels was found to reduce post-traumatic cerebral edema. [ABSTRACT FROM AUTHOR]

First-principles calculations of structural, electronic, optical, elastic, mechanical properties, and Born effective charges of monoclinic HfO2 are performed with the plane-wave pseudopotential technique based on the density-functional theory. The calculated structural properties are consistent with the previous theoretical and experimental results. The electronic structure reveals that monoclinic HfO2 has an indirect band gap. The analyses of density of states and Mulliken charges show mainly covalent nature in Hf-O bonds. Optical properties, including the dielectric function, refractive index, extinction coefficient, reflectivity, absorption coefficient, loss function, and optical conductivity each as a function of photon energy are calculated and show an optical anisotropy. Moreover, the independent elastic constants, bulk modulus, shear modulus, Young's modulus, Poisson's ratio, compressibility, Lamé constant, sound velocity, Debye temperature, and Born effective charges of monoclinic HfO2 are obtained, which may help to understand monoclinic HfO2 for future work. [ABSTRACT FROM AUTHOR]

Several representative ionic liquids (ILs) were synthesized, and [Emim]OAc was chosen as environment-friendly solvent for enzymatic in situ saccharification in view of its biocompatibility with both natural and microcrystalline cellulose, as well as its enzymatic activity. With the microwave pretreatment of natural and microcrystalline cellulose, directly enhancing the in situ enzymatic saccharification, the rate was compared versus an untreated control by the detection of dinitrosalicylic acid (DNS). It is suggested that the molecular structure of cellulose in the process of pretreatment was changed, e.g. intramolecular hydrogen bonds were broken (detected by FT-IR), and the crystallinity (monitored by SEM and XRD) changed significantly from a crystalline to an amorphous pattern. These changes of cellulose led to an increase of reducing sugar conversion during cellulose enzymatic hydrolysis. [ABSTRACT FROM AUTHOR]

A theoretical study is shown for the structural, electronic, mechanical and surface properties of α-type hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in the framework of near-first-principles density-functional theory. The calculated results indicate that α-RDX is an insulator material with an indirect bandgap and shows the anisotropic impact sensitivity along different directions. The directional dependence of Young's modulus is obtained, showing the anisotropic elasticity is related to the anisotropic impact sensitivity. The influences of surfaces on sensitivity indicate that the more sensitivity of the surface is, the bigger surface energy is. [ABSTRACT FROM AUTHOR]

The dehydration of fructose to 5-hydroxymethylfurfural (HMF) was investigated in the presence of the Brönsted-Lewis acidic ionic liquids (ILs). It was found that IL (3-sulfonic acid)-propyl-triethylammonium chlorochrominate [HO3S-(CH2)3-NEt3]Cl-CrCl2 (molar fraction of CrCl2 x = 0.55) had a good catalytic performance with 93.4% yield of HMF. IL acid site played a more significant role than its Brönsted counterpart in the reaction, and a synergetic effect of Brönsted and Lewis acid sites enhanced IL catalytic performance. The reusability of IL was good which could be reused up to 5 times without apparent decrease in the yield of HMF. [ABSTRACT FROM AUTHOR]

Deficiency of the organs is a vital pathophysiologic characteristic in the elderly. A core TCM aging theory is known as aging caused by spleen deficiency syndrome (SDS) that can be found in ancient and modern literature.The key objectives of this study were to establish a full-scale trial to evaluate the prevalence, symptom severity, frequency, and distribution of SDS in different age groups as related to health status (healthy, sub healthy, and chronic disease) to elucidate the role of spleen deficiency in the aging process and deterioration of health status. This cross-sectional observational study was conducted in 4 hospitals in China. 1390 participants aged 20-79 were interviewed by investigators who completed questionnaires recording prevalence, severity, and frequency of symptoms as well as other relevant information. The results revealed that prevalence and symptom characteristics of SDS showed regularities with increasing age and deteriorating health status. It supports the TCM concept that spleen deficiency is an important mechanism of aging, subhealth, and chronic diseases. Early recognition of the warning signs and symptoms of SDS may lead to intervention and even prevention strategies for subhealth and chronic diseases as well as promotion of healthy aging. [ABSTRACT FROM AUTHOR]

First-principle simulations have been applied to investigate the effect of copper (Cu) or aluminum (Al) content on the ductility of Al3Ti, AlTi, AlCu, and AlTiCu2 alloys. The mechanical stable and elastic properties of Al-based intermetallic compounds are researched by density functional theory with the generalized gradient approximation (DFT-GGA). The calculated lattice constants are in conformity with the previous experimental and theoretical data. The deduced elastic constants show that the investigated Al3Ti, AlTi, AlCu, and AlTiCu2 structures are mechanically stable. Shear modulus, Young’s modulus, Poisson’s ratio, and the ratio B/G have also been figured out by using reckoned elastic constants. A further analysis of Young’s modulus and Poisson’s ratio reveals that the third added element copper content has significant effects on the Al–Ti-based ICs ductile character. [ABSTRACT FROM AUTHOR]