Polymerase chain reaction based C4AQ0 and C4BQ0 genotyping: association with systemic lupus erythematosus in southwest Han Chinese

Objective: To investigate the association of complement C4 null genes (C4QO, including C4AQO and C4BQO) and C2 gene with systemic lupus erythematosus (SLE) in southwest Han Chinese; 136 patients with SLE and 174 matched controls were genotyped. Methods: C4 null genes were determined by a polymerase chain reaction (PCR) procedure with sequence specific primers (PCR-SSP). The 2 bp insertion in exon 29, which was previously identified in non-Chinese populations and caused defective C4A genes, was directly typed by sequencing the whole exon 29 using exon specific primers. The exon 6 of complement C2 was also sequenced in both the patients and controls. Results: The frequency of homozygous C4AQO allele was 12.5% (17/136) in patients with SLE compared with 1.1% (2/174) in controls (p<0.001, odds ratio (OR)=12.286, 95% confidence interval (95% CI) 2.786 to 54.170). There was no significant difference for homozygous C4BQO allele between patients with SLE and controls (p=0.699). Patients with the C4AQO gene had an increased risk of acquiring renal disorder, serositis, and anti-dsDNA antibodies compared with those without C4AQO (for renal disorder, p=0.018, OR=8.951, 95% Cl 1.132 to 70.804; for serositis, p=0.011, OR 4.891, 95% CI 1.574 to 15.198; for anti-dsDNA, p=0.004, OR 7.630, 95%Cl 1.636 to 35.584). None of the patients or controls had the 2 bp insertion in exon 29 of the C4 gene. The type I C2 deficiency was not detected in the 3 10 samples. Conclusion: It is suggested that deficiency of C4A (not due to a 2 bp insertion in exon 29), but not C4B or C2, may be a risk factor for acquiring SLE in south west Han Chinese; this results in increased risk of renal disorder, serositis, and anti-dsDNA antibodies in patients with SLE. Racial differences seem to be relevant in susceptibility to SLE.

Effects of gamma-aminobutyric acid, progesterone and ionophore A23187 on acrosome reaction of tree shrew sperm in vitro: examination of acrosome reaction with an improved fluorescence microscopy

A number of acrosome reaction (AR) initiators have been found to be effective in inducing AR of human, laboratory and domestic animal sperm. Using an improved simple fluorescence microscopy, effects of gamma-aminobutyric acid (GABA), progesterone and ionophore A23187 on sperm AR of tree shrew, a useful animal model in biomedical research, have been investigated. Spontaneous AR in 4.92-7.53% of viable sperm was observed. Complete AR in 10.31-18.25% of viable tree shrew sperm was obviously induced by 5 mu M and 10 mu M calcium ionophore A23187, 1 mM GABA, and 5 mu M progesterone, and there were no significant differences between their abilities to initiate complete AR. No significant differences of AR percentages between 1- and 2-h treatments with A23187, progesterone and/or GABA were observed. These results suggested that the responses of tree shrew sperm to these AR initiators are similar to that of human and other mammalian sperm. (C) 1997 Elsevier Science B.V.

Patterns and levels of PCDD/F in a Chinese graphite electrode sludge

The graphite electrode sludge was sampled from a huge chloralkali plant in central China. The total level of PCDD/F was found as high as 378.85 mu g/kg sludge (dry weight). The patterns of PCDD/F in each homologue indicated the predominance of tetra- to octa-chlorinated PCDFs, Furthermore, the toxic 2,3,7,8-substituted PCDFs constituted over 80% of the total PCDFs in the sludge and the corresponding PCDDs were only at 15 mu g/kg level. The calculated value of the international toxic equivalence (I-TEQ) in sludge was 21.65 mu g/kg sludge (dry weight). This typical "dioxin chloralkali pattern" was apparently identified in the sediments near the effluent outlet of the chloralkali plant.

A detection method for grass carp hemorrhagic virus (GCHV) based on a reverse transcription polymerase chain reaction

A rapid, sensitive and highly specific detection method for grass carp hemorrhagic virus (GCHV) based on a reverse transcription-polymerase chain reaction (RT-PCR) has been developed. Two pairs of PCR primers were synthesized according to the cloned cDNA sequences of the GCHV-861 strain. For each primer combination, only one specific major product was obtained when amplification was performed by using the genomic dsRNA of GCHV-861 strain. The lengths of their expected products were 320 and 223 bp, respectively. No products were obtained when nucleic acids other than GCHV-861 genomic RNA were used as RT-PCR templates. To assess the sensitivity of the method, dilutions of purified GCHV-861 dsRNA total genome (0.01 pg up to 1000 pg) were amplified and quantities of as little as 0.1 pg of purified dsRNA were detectable when the amplification product was analyzed by 1.5% agarose gel electrophoresis. This technique could detect GCHV-861 not only in infected cell culture fluids, but also in infected grass carp Ctenopharyngodon idellus and rare minnow Gobiocypris rarus with or without hemorrhagic symptoms. The results show that the RT-PCR amplification method is useful for the direct detection of GCHV.

Wear resistance of reaction sintered alumina/mullite composites

Alumina and alumina/mullite composites with mullite content of 0.96-8.72 vol.% were subjected to an abrasive wear test under loads of 0.1-2.0 N with a ball-on-disc apparatus. The wear rate and area fraction of pullout f(po) on the worn surfaces were measured. The wear resistances of the alumina/mullite composites were better by a factor of 1-2 than that of pure alumina. The main wear mechanism of alumina is fracture wear, and for alumina/mullite composites, fracture wear and plastic wear mechanisms work together. The influence of mechanical properties on wear resistance was estimated by Evans' method. It was found that the wear rate depends on f(po), and the primary reason for the better wear resistance of alumina/mullite composites is the reduction off, induced by fracture mode transition. (c) 2007 Elsevier B.V. All rights reserved.

Parasitic reaction and its effect on the growth rate of AlN by metalorganic chemical vapor deposition

The Al composition of metalorganic chemical vapor deposition (MOCVD)-grown AlGaN alloy layers is found to be greatly influenced by the parasitic reaction between ammonia (NH3) and trimethylaluminum (TMAI). The growth process of AlN is carefully investigated by monitoring the in situ optical reflection. The abnormal dependencies of growth rate on growth temperature, reactor pressure, and flux of NH3 are observed and can be well explained by the effect of parasitic reaction. The increase of growth rate with increasing flux of TMAI is found to depend on the growth temperature and reactor pressure due to the presence of parasitic effect. A relatively low growth temperature and a reduced reactor pressure are suggested for the effective decrease of parasitic reaction during the MOCVD growth of AlN and probably lead to a more effective incorporation of Al into the AlGaN layers. (c) 2005 Elsevier B.V. All rights reserved.

Preparation and characterization of GaN films by radio frequency magnetron sputtering and carbonized-reaction technique

Radio frequency magnetron sputtering/post-carbonized-reaction technique was adopted to prepare good-quality GaN films on Al2O3(0 0 0 1) substrates. The sputtered Ga2O3 film doped with carbon was used as the precursor for GaN growth. X-ray diffraction (XRD) pattern reveals that the film consists of hexagonal wurtzite GaN. X-ray photoelectron spectroscopy (XPS) shows that no oxygen can be detected. Electrical and room-temperature photoluminescence measurements show that good-quality polycrystalline GaN films were successfully grown on Al2O3(0 0 0 1) substrates. (c) 2005 Elsevier B.V. All rights reserved.

SiO2/Ta interface reaction in magnetic multilayers and its influence on Ta buffer layers

Ta is often used as a buffer layer in magnetic multilayers. In this study, Ta/Ni81Fe19/Ta multilayers were deposited by magnetron sputtering on sing-crystal Si with a 300-nm-thick SiO2 film. The composition and chemical states at the interface region of SiO2/Ta were studied using the X-ray photoelectron spectroscopy (XPS) and peak decomposition technique. The results show that there is an 'inter-mixing layer" at the SiO2/Ta interface due to a thermodynamically favorable reaction: 15 SiO2 + 37 Ta = 6 Ta2O5 + 5 Ta5Si3. Therefore, the Ta buffer layer thickness used to induce NiFe (111) texture increases.

Electrolyte electroreflectance spectroscopy studies on the interfacial behavior of the near-surface In0.15Ga0.85As/GaAs quantum well electrode vertical bar non-aqueous electrolyte

Electrolyte electroreflectance spectra of the near-surface strained-layer In0.15Ga0.85As/GaAs double single-quantum-well electrode have been studied at different biases in non-aqueous solutions of ferrocene and acetylferrocene. The optical transitions, the Franz-Keldysh oscillations (FKOs) and the quantum confined Stark effects (QCSE) of In0.15Ga0.85As/GaAs quantum well electrodes are analyzed. Electric field strengths at the In0.15Ga0.85As/GaAs interface are calculated in both solutions by a fast Fourier transform analysis of FKOs. A dip is exhibited in the electric field strength versus bias (from 0 to 1.2 V) curve in ferrocene solution. A model concerning the interfacial tunneling transfer of electrons is used to explain the behavior of the electric field. (C) 2001 Elsevier Science B.V. All rights reserved.

Photoelectrochemical behavior of a novel composite In0.15Ga0.85As/GaAs vertical bar GaAs/Al0.3Ga0.7As multiple quantum well electrode

A novel composite InxGa1-xAs/GaAs/GaAs/AlxGa1-xAs multiple quantum well material with different well widths was studied as a new kind of photoelectrode in a photoelectrochemical cell. The photocurrent spectrum and photocurrent-electrode potential curve were measured in ferrocene nonaqueous solution. Pronounced quantization effects and strong exciton absorption were observed in the photocurrent spectrum. The effects of surface states and interfacial states on the photocurrent-electrode potential curve are discussed. (C) 2000 Elsevier Science S.A. All rights reserved.

Compatibility relationship among reaction equilibria, equivalence principle of reaction approaches, and silicon contamination in semiconductors

This paper discovers some shortcomings in the algorithm for the incorporation of Si into GaAs in the GaAs VPE process. These faults arise from neglecting a link, the compatibility relationship, in chemical thermodynamics. The meaning of said relationship is as follows: In an equilibrium complex system, each species can only contribute one and the same quantity (its equilibrium quantity) to the different equilibria of the various reactions involving it; yet even under this restriction, every equilibrium constant is satisfied, and all the reaction equilibria coexist compatibly in the system. Only by adding the relationship can the equilibrium theory for the complex system be complete. This paper also tells its position in chemical thermodynamics. Such a compatibility concept directly leads to an equivalence principle: In a complex system, a certain species can usually be simultaneously formed by many chemical reactions; when the system has reached equilibrium under fixed environmental conditions, the equilibrium quantity of said species calculated according to each chemical equation of these reactions will be equal and the various reaction approaches will be equivalent, provided that for all the reactants and all the other products of these reactions their equilibrium quantities in the system are respectively taken as corresponding knowns for the calculations, which is extremely useful for seeking a functional relation among the species' equilibrium quantities in a system (Si contamination is one of the examples). Under the guidance of those arguments, the various schools' algorithms for the Si contamination can be uniformized and simplified, and the contamination quantity relation between Si and O, two very important impurities, is found.

Identification of induced reaction during XPS depth profile measurements of CeO2/Si films grown by ion beam epitaxy

An anomalous behavior was observed in X-ray photoelectron Spectroscopy (XPS) depth profile measurements conducted on CeO2/Si epilayers grown by ion beam epitaxy (IBE): the signals of Ce3+ and Ce4+ co-exist, and the ratio between them increases during the etching time and then tends to maintain a constant level before increasing again. The results of X-ray Diffraction (XRD), Auger Electron Spectroscopy (AES), and Rutherford Back-Scattering (RES) measurements proved that the reduction chemical reaction of CeO2 is induced by ion-etching. (C) 1998 Elsevier Science Ltd. All rights reserved.