The NO
2 and CO
2 sensing properties of a heterojunction gas sensor formed between
n-type ZnO and a
p-type composite based on a mixture of BaTiO
3/CuO/La
2O
3 have been evaluated and compared with ...the performance of its component
p- and
n-type materials. It was found that the individual ZnO and BaTiO
3/CuO/La
2O
3 sensors showed resistance increases when exposed to NO
2. When exposed to CO
2, the ZnO based sensor showed no response, while the BaTiO
3/CuO/La
2O
3 sensor showed a small resistance increase. The heterojunction sensor was found to be insensitive to <3000 ppm CO
2 although at higher concentrations it showed a small decrease in resistance. The resistance also decreased when exposed to low levels of NO
2, indicating that a different detection mechanism was operative at the heterocontact compared with the single-phase materials.
Experimental and therapeutic use of islet cell preparations could benefit from assays that measure variations in the mass of living beta-cells. Because processes of cell death can be followed by ...depletion and/or discharge of cell-specific substances, we examined whether in vitro conditions of beta-cell death resulted in changes in tissue and medium content of insulin and of gamma-aminobutyric acid (GABA), two beta-cell-specific compounds with different cellular localization and turnover. Exposure of rat purified beta-cells to streptozotocin (5 mM, 120 min) or to the nitric oxide donor GEA-3162 (GEA; 50 microM, 120 min) caused 80% necrosis within 24 h; at the end of this period, cellular insulin content was not significantly decreased, but cellular GABA content was reduced by 70%; when cultured at basal glucose (6 mM), the toxin-exposed cells did not discharge less insulin but released 80% less GABA in the period 8-24 h. As in rat beta-cell purification, GABA comigrated with insulin during human islet cell isolation. Twenty-four hours after GEA (500 microM, 120 min), human islet cell preparations exhibited 90% dead cells and a 45 and 90% reduction, respectively, in tissue insulin and GABA content; in the period 9-24 h, insulin discharge in the medium was not reduced, but GABA release was decreased by 90%. When rat beta-cells were cultured for 24 h with nontoxic interleukin (IL)-1beta concentrations that suppressed glucose-induced insulin release, cellular GABA content was not decreased and GABA release increased by 90% in the period 8-24 h. These data indicate that a reduction in cellular and medium GABA levels is more sensitive than insulin as a marker for the presence of dead beta-cells in isolated preparations. Pancreatic GABA content also rapidly decreased after streptozotocin injection and remained unaffected by 12 h of hyperglycemia. At further variance with insulin, GABA release from living beta-cells depends little on its cellular content but increases with IL-1beta-induced alterations in beta-cell phenotype.
To solve the problem of imprecise positioning of feature point and of the feature data redundancy in facial expression recognition by active appearance models (AAM), the automatic adjustment of ...initial model for AAM fitting is proposed in this paper. The specific aims are to improve the precision of positioning and to more effectively reflect the variation of expressions by acquired features. The problem of feature selection is resolved by adopting quadratic mutual information and reducing the feature dimension. The support vector machine (SVM) classifier is used for expression recognition. The experimental results on CAS-PEAL facial expression database show that the proposed method effectively improves the performance of facial expression recognition, the maximum recognition rate being 83.33%.
The Fc fragment of immunoglobulin (Ig) has been shown to play an important role in the regulation of humoral immunity, cellular immunity, lymphocyte and monocyte activation, and immune mediator ...secretion. We wished to determine if Ig or Fc fragments would induce IL-6 production from monocytes. Incubation of monocytes purified from human peripheral blood mononuclear cells with aggregated Ig or Fc fragments of Ig induced interleukin-6 (IL-6) activity in the supernatants. Monomeric Ig taken from an intravenous preparation of Ig, from which all aggregated Ig are removed, would not induce IL-6 production from monocytes whereas as a heat-treated aliquot, presumably containing aggregates, did induce IL-6. The supernatants were assayed according to their ability to induce growth in a murine hybridoma cell line B9, or enhance Ig secretion of B cells stimulated with Staphylococcus aureus Cowan 1 (SAC). The IL-6 activity in the supernatants could be neutralized by a polyclonal rabbit anti-human IL-6 antiserum in both assays of IL-6 activity. Exposure of T-enriched or B-enriched lymphocyte subpopulations to Fc fragments did not induce the release of any IL-6 after 12 hr of incubation, but small amounts of IL-6 were produced by B-enriched cells after 60 hr of exposure to Fc fragments. Hence Fc fragments and aggregated Ig induce peripheral blood monocytes to rapidly secrete large quantities of interleukin-6.
Canarium album has yielded seven triterpenes of which two appear to be novel. The new triterpenes, which were identified on the basis of spectral characteristics, are urs-12-ene-3 alpha, 16 beta-diol ...and olean-12-ene-3 alpha, 16 beta-diol. Both compounds exhibited hepatoprotective activity in primary cultured rat hepatocytes intoxicated with D-galactosamine.
Zhongzhua No. 8 and Zhongzhua No. 9 were developed using anther culture method. These two varieties have resistance gene Pi-z raised to the t which derived from Japanese variety Toride 2. Before ...releasing Zhongzhua No. 8 and Zhongzhua No. 9, Pi-z raised to the t gene was not infected by any pathogenic races in rice-cropping regions of north China. After releasing these two varieties, many new pathogenic races that can invade Pi-z raised to the t gene occurred in rice cropping regions of north China. These new pathogenic races invaded a lot of cultivated varieties and many breeding materials which include developing lines and resistance donors. In order to provide new resistance resources with broader resistance spectrums for rice breeding for resistance to blast disease, many local japonica varieties from Yunnan province in China were identified for their blast resistance by using seven Japanese representative strains and 15 Chinese representative strains and new strains with broad virulence spectrum. Analyzed resistant varieties include Hongliandaogu-1, Mengwanggu-1, Dabainuo, Haobian-1, Zhamianni-1 and Buzha-1. The results indicated that Haobian-1, and Zhamianni-1 have one dominant resistance gene and Mungwanggu-1, Hongliandaogu-1 and Dabainuo-1 have two dominant resistance genes, respectively. On the basis of results of the allelism test, it was concluded that: 1)analyzed local japonica varieties from Yunnan province have new resistance genes different from named genes in Japanese differential varieties; 2) the resistance spectrum of new genes in these resistant varieties is broader than that of named genes. Therefore, these new resistance genes have more highly available value in rice breeding for resistance to blast disease in north China
By selecting from a genomic library of rice blast fungus strain Hokul, a repeated sequence named POR6 was cloned and verified that it is a genome specific and dispersed repeated sequence, which can ...be used to fingerprint various kinds of rice blast pathotypes. It was sequenced and the copy number has been determined. The electrophoresis of karyotypes of Hokul reveals 4 chromosomes ranging from about 2 to 6 Mb in length. POR6 has been proven to be distributed on all of them by Southern analysis. Some blast isolates in the laboratory were proven variable from generation to generation in their pathotypes identified by the traditional method. By using POR6 as a probe, 3 to 4 bands of variation in DNA fingerprints across generations can be detected
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