Cooperative Shear in Bulk Metallic Glass Composites Containing Metastable ß-Ti Dendrites.

We report a novel plastic deformation mechanism of bulk metallic glass composites (BMGCs) containing metastable ß-Ti dendrites. Plastic deformation of the BMGCs beyond the ultimate tensile strength is mediated by cooperative shear events, which comprise a shear band in the glassy matrix and a continuous ω-Ti band with a thickness of ∼10 nm in the ß-Ti dendrite. The cooperative shear leads to serrated shear avalanches. The formation of narrow ω-Ti bands is caused by high local strain rates during the cooperative shear. The cooperative shear mechanism enriches the deformation mechanisms of BMGCs and also deepens the understanding of ω-Ti formation.

Hydrothermal synthesis of Zn2SnO4 as anode materials for Li-ion battery.

Spinel Zn2SnO4 particles with the cubic shape are prepared via a hydrothermal reaction under mild conditions. The hydrothermal conditions, such as alkaline concentration, reaction temperature, and duration time, have an important influence on the product structure and the performance of the electrode prepared with the product. The optimized product is cube-shaped Zn2SnO4 crystalline, which is prepared with 0.4 M of NaOH solution at 200 degrees C for 24 h. These cube-shaped Zn2SnO4 particles with the spinel structure exhibit a large electrochemical capacity of 988 mA h/g and a relatively good capacity retention as anode materials for Li-ion battery. The structures of the as-prepared product and specimens taken from the electrodes after charging-discharging cycles are analyzed by X-ray diffraction, scanning electron microscopy, and transition electron microscopy techniques. In particular, it is found for the first time that the spinel Zn2SnO4 structure exists to a great extent after the first cycle and contributes to the extremely high reversible capacity during the following cycles.

Praseodymium hydroxide and oxide nanorods and Au/Pr6O11 nanorod catalysts for CO oxidation.

Praseodymium hydroxide nanorods were synthesized by a two-step approach: First, metallic praseodymium was used to form praseodymium chloride, which reacted subsequently with KOH solution to produce praseodymium hydroxide. In the second step the hydroxide was treated with a concentrated alkaline solution at 180 degrees C for 45 h, yielding nanorods as shown by the scanning and transmission electron microscopy images. The results of X-ray diffraction and energy-dispersive X-ray spectroscopy experiments indicate that these nanorods are pure praseodymium hydroxide with a hexagonal structure, which can be converted into praseodymium oxide (Pr6O11) nanorods of a face-centered cubic structure after calcination at 600 degrees C for 2 h in air. Gold was loaded on the praseodymium oxide nanorods using HAuCl4 as the gold source, and NaBH4 was used to reduce the gold species to metallic nanoparticles with sizes of 8-12 nm on the nanorod surface. These Au/Pr6O11 nanorods exhibit superior catalytic activity for CO oxidation.

Preparation and electrochemical hydrogen storage of boron nitride nanotubes.

Boron nitride (BN) nanotubes were synthesized through chemical vapor deposition over a wafer made by a LaNi5/B mixture and nickel powder at 1473 K. Scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were performed to characterize the microstructure and composition of BN nanotubes. It was found that the obtained BN nanotubes were straight with a diameter of 30-50 nm and a length of up to several microns. We first verify that the BN nanotubes can storage hydrogen by means of an electrochemical method, though its capacity is low at present. The hydrogen desorption of nonelectrochemical recombination in cyclic voltammograms, which is considered as the slow reaction at BN nanotubes, suggests the possible existence of strong chemisorption of hydrogen, and it may lead to the lower discharge capacity of BN nanotubes. It is tentatively concluded that the improvement of the electrocatalytic activity by surface modification with metal or alloy would enhance the electrochemical hydrogen storage capacity of BN nanotubes.

CeO2 nanorods and gold nanocrystals supported on CeO2 nanorods as catalyst.

The formation mechanism of uniform CeO2 structure at the nanometer scale via a wet-chemical reaction is of great interest in fundamental study as well as a variety of applications. In this work, large-scale well-crystallized CeO2 nanorods with uniform diameters in the range of 20-30 nm and lengths up to tens of micrometers are first synthesized through a hydrothermal synthetic route in 5 M KOH solution at 180 degrees C for 45 h without any templates and surfactants. The nanorod formation involves dehydration of CeO2 nanoparticles and orientation growth along the 110 direction in KOH solution. Subsequently, gold nanoparticles with crystallite sizes between 10 and 20 nm are loaded on the surface of CeO2 nanorods using HAuCl4 solution as the gold source and NaBH4 solution as a reducing agent. The synthesized Au/CeO2 nanorods demonstrate a higher catalytic activity in CO oxidation than the pure CeO2 nanorods.

Safety and immunogenicity of live attenuated hepatitis A virus vaccine (H2 strain) in humans.

A study was made in Neijiang City, Sichuan Province to observe the safety and immunogenicity of a live attenuated hepatitis A virus (HAV) vaccine (H2 strain). 3,031 children, aged 6 to 9 years, were injected subcutaneously with 10(6.0) TCID50, 10(5.5) TCID50, and 10(5.0) TCID50 of HAV vaccine; the seroconversion rate and antibody GMT were 97.52%-90.68%, GMT = 1:5.19 +/- 1.90-1:3.36 +/- 1.94; 84.75%-76.27%, GMT = 1:4.29 +/- 1.96-1:2.0 +/- 2.67; 53.23%-51.61%, GMT = 1:2.57 +/- 1.89-1:1.68 +/- 1.41 respectively after 4 weeks to 12 months of inoculation. Forty-eight children in the control group were anti-HAV negative at 4, 8, and 12 weeks; 21 children in the oral group were not antibody positive 4 and 8 weeks after oral administration of the vaccine. The stool specimens of 3 of the 14 vaccinated children were HAA positive. The results suggest that the live attenuated HAV vaccine (H2 strain) is of good immunogenicity and safety.

Clinical and experimental studies on paediatric pneumonia treated by lung easing tablets.

197 cases of paediatric pneumonia from 2 hospitals were treated by Ning Fei Pian (NFP, the Lung Easing Tablets), a proprietary Chinese medicine for antipyresis, detoxication, blood invigoration, resolution of cough and phlegm; the control group was treated by penicillin, and the therapeutic results were comparable. Examinations of microcirculation and hemorrheology in the nailbed revealed improvements by NFP, which were conducive to the recovery of pneumonia. Electron-microscopically, the tablets also produced improvements in microcirculation, relief of lung edema, and the ratio of ventilation and blood flow.

[Clinical and experimental studies of effects of huayu decoction on scavenging free radicals].

Infantile pneumonia has been treated successfully with Huayu decoction (HYD) in our department for more than ten years. According to the principles of Huoxue Huayu of TCM, the composition of Huayu decoction is as follows: Angelica sinensis, Paeonia lactiflora, Ligusticum wallichii, Spathollobus suberectus, Hirudo nipponica, Tabanus bivittatus, Paeonia suffroticosa, Astragalus membranaceus . 49 cases of infantile pneumonia were treated with HYD. The activity of erythrocyte superoxide dismutases (ESOD) was measured in these patients. The results showed that the activity of ESOD reduced in the acute stage and returned to normal in convalescence. There was significant statistical difference in activity of ESOD between the patient's group. In experimental studies, the producing of free radicals was induced by inhaling ozone in mice. It was found that HYD had the effect of scavenging free radicals in these animal models. The action of anti-oxidate of HYD was also detected in vitro. The mechanism of HYD in treating infantile pneumonia might be elucidated in some respects by these clinical and experimental studies.

[Ezhu intravenous injection in treating infantile respiratory syncytial virus pneumonia and its therapeutical mechanism].

Ezhu Intravenous Injection (EII) in treating respiratory syncytial virus (RSV) pneumonia was studied. 45 patients in therapeutic group were treated with 0.04% EII in dose of 20 ml/kg/day for 7-14 days. 20 patients in the control group were treated with Huayu decoction, its efficacy on RSV pneumonia has been confirmed. The results showed that all the patients of both groups were cured and there were no statistic differences in the average days of clearing up the temperature, dyspnea and wheezing (P > 0.05). Experimental studies showed that the isolation rate of RSV on the 5th and 8th day in the therapeutic group were lower than that of infected and glucose control groups. The difference was significant (P < 0.001 and P < 0.0001). Pathological examination showed that on 5th day in infected and control group there were epithelial damages and bronchial lumen obstruction, peri-bronchial and periseptal edema, eosinophilic leucocytes and inflammatory infiltrations. The endothelial cells of alveolar capillaries swelled, platelet aggregations and thrombi occurred in its lumens. On 8th day the platelet aggregations diminished, but cellular infiltrations and damages of bronchial epithelium still existed. In therapeutic group on 5th day most of the alveolar capillary endothelial cells were normal with mild edema only. The platelet aggregation were much less than the infected and control groups. No peribronchial and peri-septal edema was observed. The results of both clinical and experimental studies showed that EII had good therapeutic effect on RSV pneumonia with no adverse reaction.

Isolation, characterization, and localization of the zona pellucida binding proteins of boar sperm.

In order to isolate the putative zona pellucida-binding proteins (ZPBPs) from boar spermatozoa, a new, simple method has been developed. The new isolation strategy made the most of the highly specific interactions between the components of the gametes. Detergent-extracted boar sperm proteins were submitted to affinity chromatography on a ZP-Sepharose column. SDS-PAGE analyses of the retained fraction under reducing conditions revealed that in addition to a component of Mr 38,000, the predominant ZPBPs contained at least three low molecular weight proteins (Mr less than 20 kDa). The isolated ZPBPs were effective in blocking sperm-oocyte binding in vitro. Using immunofluorescence microscopy, the ZPBPs were shown to be localized primarily in the sperm head, especially in the acrosomal cap region.