Comparison of primary and secondary aminosilance coupling agents in anhuydride-curde epoxy fiberglass composites

Fourier transform infrared spectroscopy (FT-IR) has been utilized to investigate the interfacial chemical bonding at the interfaces of the aminosilanes and the nedic methyl anhydiride cured epoxy matrix in fiber-reinforced composites. It is found that the nedic methyl anhydride can react with γ-aminopropyltriethoxysilane (APS) and N-methylaminoproplytrimethoxysilane (MAPS). In comparing the relative reactivities of two coupling agents to the epoxy resin, the secondary aminosilance has a higher reactivity than the primary aminosilance. An elevated temperature is required for the copolymerization to take place between the silane and the epoxy resin. The results indicate that covalent bonds form at the coupling agents. The molecular structure of the interface in MAPS treated fiberglass reinforced composites is different from that of the APS treated fiber composites. In addition, an accelerated copolymerization initiated by the coupling agent treated surface is also found in the resin interphase which may be important in determining the mechanical properties of the composites.     

Separation of gamma-globulins from porcine plasma by reversed micellar extraction

Factors affecting the separation of gamma-globulins from porcine plasma using reversed micelles were screened based on a fractional factorial design. The optimal processing conditions for obtaining the maximum yield of gamma-globulins under various constraints of product purity were determined using response surface methodology (RSM) and nonlinear programming. Results showed that the pH and sodium chloride concentration of the aqueous phase, and the concentration of surfactant (bis-(2-ethylhexyl) sulfosuccinate sodium salt, AOT) of the organic phase were the most important factors affecting the extraction performance. An eighty-five percent product purity and ninety-seven percent yield were obtained under the extraction conditions of 400 mM NaCl, 350 mM AOT, and pH 7.0. The extract exhibited immunological reactivity against anti-pig IgG.     

Dephytinisation of rice bran and manufacturing a new food ingredient

Rice bran was extruded at 130 °C and a screw speed of 140 rpm for 20 s to inactivate lipase and prevent lipid oxidation. Although the extrusion process induced further complex formation between phytic acid and protein as well as between phytic acid and starch, nearly 94% of phytic acid in the extruded rice bran could still be removed by solid/liquid extraction conducted at 25 °C for 30 min using hydrochloric acid at pH 2 as solvent and a solvent/rice bran ratio of 15. After the extract had been neutralised and phytic acid removed, it was added back to the rice bran solid to replenish the nutritional and functional components of the solid. The mixture was then dried in a drum dryer to yield a powdered product. The dephytinised rice bran product contained most of the protein, fat, dietary fibre and B vitamins and more than 50% of the oryzanol originally present in the raw rice bran. © 2001 Society of Chemical Industry     

Chemical reactions occurring at the interface of epoxy matrix and aminosilane coupling agents in fiber-reinforced composites

The chemical reactions at the interface between an anhydride-cured epoxy resin and an aminosilane treated fiber have been investigated using Fourier transform infrared methods (FT-IR). The results indicate that chemical bonds are formed in the interfacial region between the matrix and the coupling agents. The amount of interfacial bonding depends on the composition and the processing conditions.     

大气红外探测仪的探测器序列定位误差

大气红外探测仪AIRS的核心是一个光栅光谱仪序列,2378个红外探测器分装在17个探测器序列上,本文以实例说明了由于探测器序列在视轴方向有偏移,即空间错误定位误差给AIRS的观测值带来的影响及其光谱分布特征,以及观测值误差对后继红外晴空订正和大气廓线反演的影响.建议以后在设计同类仪器时要避免探测器序列错误定位问题,或选用干涉式分光系统.     

Expression and purification of goat lactoferrin from Pichia pastoris expression system

ABSTRACT:  The recombinant goat lactoferrin (rGLF) was expressed in the methylotropic yeast Pichia pastoris using pGAPZαC vector, GAP as promoter, and Zeocin as the selective marker. After transformation of the GLF-pGAPZαC into Pichia pastoris X-33 expression host, the GLF-pGAPZαC vector was integrated into the GAP promoter locus of Pichia pastoris X-33 chromosome. The rGLF was expressed and secreted into the broth using α-factor preprosequence. SDS-PAGE and PAS staining analysis indicated that the rGLF could be purified to electrophoretic homogeneity by heparin-Sepharose 6 Fast Flow affinity chromatography and glycosylated by the expression host. The yield of purified rGLF was approximately 2.0 mg/L of culture broth. The N-terminal sequence was identical to the native goat lactoferrin (nGLF). The iron-binding behavior, papain-inhibiting property, and thermal stability of the purified rGLF were comparable to nGLF. This is the 1st report of intact goat lactoferrin expression using the P. pastoris system.     

Gaseous hydrogen embrittlement of PH 13-8 Mo steel

In this study, notched tensile and fatigue crack growth tests in gaseous hydrogen were performed on PH 13-8 Mo stainless steel specimens at room temperature. These specimens were susceptible to hydrogen embrittlement (HE), but at different degrees, depending on the aging conditions or the microstructures of the alloys. In hydrogen, the accelerated fatigue crack growth rate (FCGR) usually accompanied a reduced notched tensile strength (NTS) of the specimens, i.e., the faster the FCGR the lower the NTS. It was proposed that the same fracture mechanism could be applied to these two different types of specimens, regardless of the loading conditions. Rapid fatigue crack growth and high NTS loss were found in the H800 (426 °C under-aged) and H900 (482 °C peak-aged) specimens. The HE susceptibility of the steel was reduced by increasing the aging temperature above 593 °C, which was attributed to the increased amount of austenite in the structure. Extensive quasi-cleavage fracture was observed for the specimens that were deteriorated severely by HE.     

Intracavernous Injection of Platelet-Rich Plasma Therapy Enhances Erectile Function and Decreases the Mortality Rate in Streptozotocin-Induced Diabetic Rats

Erectile dysfunction (ED) is an agonizing complication of diabetes mellitus (DM) and it is challenging to treat ED in DM patients. Platelet-rich plasma (PRP) is a unique therapeutic strategy comprising intrinsic growth factors. An attempt was made to explore the potentiality of the PRP treatment in DM-induced ED rats in various groups (control, DM-non-ED, DM-ED, and DM-ED treated with PRP). Streptozotocin (STZ) was used to induce DM in rats. The blood glucose levels of the DM rats were maintained at >300 mg/dl. In the 18-week experiment, survival rate, body weight, intracavernous pressure (ICP) variations, and arterial blood pressure were analyzed. The tissue restoration results were validated by histological, immunofluorescence, and transmission electron microscopic analysis. PRP treatment of DM-ED rats significantly increased all parameters of erectile function compared to pre-treatment of PRP and DM-ED treated with vehicle. The histological results revealed that PRP treatment substantially enhanced the regeneration of myelinated nerves and decreased the atrophy of corporal smooth muscle. Notably, the PRP treatment immensely enhanced the survival rate in post-surgery DM-ED rats. These results indicated certain benefits of PRP treatment in delaying damage and preventing post-surgery complications in DM patients. Hence, PRP treatment is a novel multifactorial strategy for DM-ED patients.     

Magnetic actuator design for single-axis micro-gyroscopes

An innovative magnetically levitated system design is presented in this paper. The proof mass, used as the seismic detection components for gyroscopes, is levitated by the presented micro-coil actuator so that the concerns that mechanical fatigue, asymmetry and mis-alignments, which are inevitably present in the traditional mechanical springs design, can be ruled out. In addition, the limited range of dual-axis motion of the proof mass is completely relaxed and therefore the resolution and sensitivity of the gyroscope can be greatly upgraded. That is, the proof mass can be much at higher frequencies and the stroke of the sense-mode motion can be more enlarged, in comparison with the conventional design (i.e., mechanical springs). In addition, self-sensing technique is employed to replace the gap sensors which provide the feedback signal for position regulation of the proof mass, for the sake of cost-down for mass production. A sliding mode control strategy is included to account for the effects of nonlinearity of the maglev system dynamics and hysteresis uncertainty of the micro-coil actuator. The proposed controller is verified by computer simulations and experiments to illustrate its superior capability to stabilize the inherently unstable maglev system and ensure fast response for the lateral position regulation of the seismic proof mass.