Effect of La on heat production by mitochondria isolated from hybrid rice

The effect of lanthanum on mitochondria isolated from hybrid rice Fengyou 559 (Oryza sativa L.) was investigated. Through in vivo culture, low-dose La³⁺ promoted, but higher dose La³⁺, restrained mitochondrial heat production. However, through in vitro incubation, La³⁺ manifested only inhibitory action on mitochondrial energy turnover, the concentration required for 50% and 100% inhibition being 50.9 and 230.2 μM (57.6 nmol/mg protein), respectively. In addition, La³⁺, like Ca²⁺, induced rice mitochondrial swelling and decreased membrane potential (Δψ), which was inhibited by the specific permeability transition inhibitor cyclosporine A (CsA). The induction approached a constant limitation while mitochondrial metabolism was completely prevented by La³⁺, and microscopy observation showed a high disruption of inner mitochondrial membrane in this state. These results demonstrated that lanthanum influenced rice mitochondria in vivo and in vitro via different action pathways, and the latter involved the opening of rice mitochondrial permeability.     

Chitosan macroporous asymmetric membranes—Preparation,characterization and transport of drugs

Chitosan macroporous membranes with asymmetric morphology were obtained by using an inorganic porogen agent (SiO₂). Chitosan/silica ratios used were 1:1, 1:3, and 1:5 w/w. A methodology to obtain asymmetric membranes with control of porosity and average pore size was proposed. The porous membranes were obtained taking advantage of the opposite solubility characteristics of chitosan and silica (4–20 μm). The membranes were characterized by SEM and water sorption capacity. The porosity was calculated by the relationship between dense and macroporous membranes. The SEM images of both surfaces and cross-section of the membranes confirmed their asymmetric morphology. Using a double-cell method, the permeability coefficients of two model drugs (sodium sulfamerazine and sulfametoxipyridazine) were determined. The effects of porous layer, drug type, concentration and temperature were evaluated. The results revealed that the increase in porosity results in significant differences in permeability and that the effects of drug concentration and bath temperature become less pronounced as porosity increases. The mass transport was analyzed in terms of pore-flow mechanism and the solution-diffusion mechanism. The results showed that the methodology was very efficient to yield asymmetric membranes with good mechanical resistance, control of porous size and dense layer thickness and that these membranes can potentially be used to the transport of drugs.     

Characterization and evaluation of commercial poly (vinylidene fluoride)‐g‐sulfonatedPolystyrene as proton exchange membrane

The possibility of developing low‐cost commercial grafted and sulfonated Poly(vinylidene fluoride) (PVDF‐g‐PSSA) membranes as proton exchange membranes for fuel cell applications have been investigated. PVDF‐g‐PSSA membranes were systematically prepared and examined with the focus of understanding how the polymer microstructure (degree of grafting and sulfonation, ion‐exchange capacity, etc) affects their methanol permeability, water uptake, and proton conductivity. Fourier transform infrared spectroscopy was used to characterize the changes of the membrane's microstructure after grafting and sulfonation. The results showed that the PVDF‐g‐PSSA membranes exhibited good thermal stability and lower methanol permeability. The proton conductivity of PVDF‐g‐PSSA membranes was also measured by the electrochemical impedance spectroscopy method. It was found that the proton conductivity of PVDF‐g‐PSSA membranes depends on the degree of sulfonation. All the sulfonated membranes show high proton conductivity at 92°C, in the range of 27 to 235 mScm⁻¹, which is much higher than that of Nafion212 (102 mScm⁻¹ at 80°C). The results indicated that the PVDF‐g‐PSSA membranes are particularly promising membranes to be used as polymer electrolyte membranes due to their excellent stability, low methanol permeability, and high proton conductivity.     

多孔岩芯渗透率与孔隙度的MRI研究

运用自旋回波序列,得到一系列用盐水饱和的多孔岩芯的磁共振自旋密度象,可以直观、准确地观察岩芯的结构,并对象的信号强度与渗透率和孔隙度之间的相关关系进行了分析,发现它们之间存在良好的定性关系,得到了较好的结果.     

Spatial correlations in permeability distributions due to extreme dynamics restructuring of unconsolidated sandstone

We propose a model for porous sandstone formation from unconsolidated sand based on a series of restructuring events where the local pressure difference due to flow in the sand is the largest. We investigate the local and global permeability distributions after steady state has been reached. Whereas we find no spatial correlations in the local permeability distribution, the distribution of inverse permeability shows spatial correlations consistent with a fractional Brownian noise characterized by a Hurst exponent of 0.88(9). The global permeability of the system shows time fluctuations as restructuring proceeds consistent with self-affinity characterized by a Hurst exponent of 0.25(3), crossing over to white noise at larger time scales.     

Crystallisation progress in Si-rich ultra-soft nanocomposite alloy fabricated by melt spinning

The crystallisation process and the ultras-soft magnetic properties of amorphous/nanocomposite alloy Fe_73.5Si_17.5B₅Nb₃Cu₁ fabricated by conventional melt-spinning technique are systematically investigated in terms of thermal analysis and in-situ measurement of magnetisation dynamics. The thermal analysis using differential scanning calorimetry showed that crystallisation from Fe-based amorphous state to α-Fe(Si) started at . Further heating the sample leads to a transformation from the α-Fe(Si) to Fe-B phases at . Crystallisation activation energies were determined using two models: Kissinger and John-Mehl-Avrami (JMA), which were consistent to each other with a value of . High resolution transmission electron microscopy investigation revealed an ultrafine structure of α-Fe(Si) nanocrystallite with mean size of 12.5 nm embedded in an amorphous matrix. At a volume fraction of 86% of α-Fe(Si) phase, optimum soft magnetic properties were obtained with very high permeability of 110,000 and a very low coercivity of 0.015 Oe by annealing the amorphous alloy at in 40 min.     

Transport parameters of carbon dioxide in poly(etheretherketone) membranes

Sorption and permeability measurements have been performed to determine the transport parameters of carbon dioxide through dense homogeneous PEEKWC membranes. The enthalpy of solution of CO₂ is exothermic. The concentration dependence of diffusion has been measured. Permeability coefficients obtained from sorption data have been compared with the experimental values, obtaining a good agreement.     

Domain wall pinning in polycrystalline perovskite La0.7Sr0.3MnO3

Reversible and irreversible domain wall (DW) motions have been investigated in La_0.7Sr_0.3MnO₃ ceramic samples using frequency-response complex permeability with various amplitudes of AC field. We also examine the effects of temperature in the range from 293 to 368 K and transverse DC magnetic field with a maximum of 4.40×10⁵ A/m on the real part of permeability (μ′). Two relaxations corresponding to reversible wall motions and domain rotations occur in low and high frequency regions, respectively. The irreversible DW displacements can be activated as the amplitude larger than the pinning field of 3 A/m, leading to an increase in μ′. The μ′ obeys a Rayleigh law at the temperature below 343 K or under DC field of less than 4.22×10⁴ A/m. The Rayleigh constant η increases from 5.45×10⁻² to 1.54×10⁻¹ (A/m)⁻¹ as the temperature rises from 293 to 343 K, and η decreases from 5.58×10⁻² to 3.67×10⁻² (A/m)⁻¹ with increasing DC field from 1.99×10³ to 4.22×10⁴ A/m.     

Improvement of polyacrylate coating by filling modified nano-TiO2

Nano-TiO₂ is modified by a method, by which nano-TiO₂ first reacts with silane coupling agent WD-70 with double bond group which subsequently copolymerizes with methyl methacrylate and butyl acrylate to produce a thin polymer shell on the nanoparticles. The modified nanoparticles have stable organophilicity. They are applied to polyacrylate coating and performances of the coating are measured by different methods. The modification of nano-TiO₂ particles can improve their dispersibility in coating, enhance hardness of coating and reduce water absorption and permeability of polyacrylate coating. The mechanism has been analyzed in this paper.     

聚乙烯醇缩醛膜阻气性能的研究

 为了提高激光靶丸的阻气性能，用戊二醛对阻气层材料聚乙烯醇进行交联改性。在17份完全相同的10 mL质量分数3%的聚乙烯醇(PVA)和20 μL浓盐酸混合溶液中，分别加入从300 μL到1 700 μL的戊二醛(GA)，交联反应后，测量缩醛膜的阻气性能，并计算渗透系数。 结果表明，随着缩醛膜中戊二醛含量的增加，缩醛膜渗透系数的变化规律是：从减小到增加到不变再到增加；当戊二醛的含量是800 μL时，缩醛膜的渗透系数最小，阻气性能最好。