Search

Iridium is the most promising material for ultra - high temperature structure parts oxidation - resistant coatings in aerospace field due to its high melting point, strong corrosion resistance and low oxygen permeability under high temperature. The main factors affecting the service life of the iridium coating were the microstructure and oxidation characteristics at high temperature. There were two ways to improve high temperature oxidation resistance of the coating: one was improving preparation process to enhance density of iridium coating so as to reduce coating failure caused by grain boundary diffusion, the other was preparing ceramic coating or alloying to defend iridium coating from contacting with the oxidizing environments and extend its lifetime. Aiming at the problems in the applications of iridium coating, the research progress on modification of iridium coating was reviewed. The development direction of iridium coating modification technology was prospected.

Abstract: Ginsenoside F2 (F2) is a potential bioactive metabolite of major ginsenosides. The potential anti-cancer effect of F2 in gastric cancer cells has not been appraised. This study investigated the effects of F2 on the production of reactive oxygen species (ROS). We also investigated the in vitro and in vivo effects of F2 on the downstream signaling pathways leading to apoptosis in human gastric cancer cells. The in vitro data revealed that F2 induces ROS accumulation followed by a decrease in mitochondrial transmembrane potential (MTP), and the release of cytochrome c (cyto c), which induced the caspase-dependent apoptosis. Further assay indicated that modulation of ASK-1/JNK pathway contributes to apoptosis. In vivo, F2 exhibits the obvious anti-cancer effect compared with cisplatin with no obvious toxicity. Jointly, these results suggest that F2 induces apoptosis by causing an accumulation of ROS and activating the ASK-1/JNK signaling pathway. This provides further support for the use of F2 as a novel anticancer therapeutic candidate. [Copyright &y& Elsevier]

In this study , 48 SSR markers were used to assess the genetic variation of 63 peanut cultivars. The results showed that total 251 polymorphic alleles were detected , and the number of polymorphic fragments per marker ranged from 2 to 13 with an average of 5. 23. The genetic diversity index ranged from 0. 508 to 2. 243 with an average of 1.272. Polymorphism information content (PIC) ranged from 0. 252 to 0. 873 with an average of 0. 647 per primer pairs. Genetic similarity coefficients (GS) ranged from 0.657 to 0 . 9 6 0 , GS were lower among different botanical types , and genetic relationship was more distant among different origins. Cluster analysis was performed with the GS and the UPGMA method. 63 cultivars were divided into 4 groups at the threshold of 0. 74. The result of clustering analysis supported the conventional classification. [ABSTRACT FROM AUTHOR]

A convenient, rapid, and environmentally benign protocol is described for the preparation of fully substituted via four-component reactions between 2-substituted acetophenones, aromatic aldehydes, malononitrile, and ammonium acetate under with good yield and without solvent. [ABSTRACT FROM AUTHOR]

A series of 4-aryl-hexahydroquinolines were prepared by Hantzsch reaction using aromatic aldehydes obtained from lignin, 1,3-cyclohexanediones, β-ketoesters and ammonium carbonate. The antioxidant properties of compounds 5a-c and 5g-i were evaluated by two methods: scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and scavenging effect on 2,2'-azino-bis(3-ethylenzothiazoline-sulfonic acid) diammonium salt (ABTS+) radical. The results show that the compounds containing a methoxy moiety exhibit good activities. The study suggests that some synthesized compounds may serve as promising leads for the treatment against tumors or other free radical-related diseases. [ABSTRACT FROM AUTHOR]

Two H5N1 avian influenza viruses (AIV), A/mallard/Huadong/S/2005 (S, IVPI = 2.65, in mallard) and A/mallard/Huadong/Y/2003 (Y, IVPI = 0, in mallard), were capable of distinct in pathogenicity to non-immunized mallards (Anas platyrhynchos). There were two amino acid residues difference in the HA cleavage site between two viruses, 322 (S, Leu; Y, Gln) and 329 (S, deletion; Y, Lys). Based on the variation, a series of recombinant viruses carrying HA gene either from S or Y virus with mutation at 322 and/or 329 were constructed via reverse genetics system to explore the influence of the two amino acid residues on viral pathogenicity in mallards. Recombinant viruses with S virus backbone were completely attenuated in terms of their virulence to ducks when position 322 (L322Q) and/or position 329 (-329K) of HA gene had been mutated. The critical role that L322 and -329 of HA protein from S virus play in the high virulence to ducks were influenced by the entire background of that protein because the recombinant virus with HA gene from Y and other seven genes from S were completely attenuated even if Q322L and K329- mutations of HA gene had been achieved. Recombinant viruses with Y virus backbone significantly increased their virulence to ducks when position 322 (Q322L) and/or position 329 (K329-) of HA gene had been mutated. All recombinant viruses carrying HA gene from Y with Q322L and/or K329-mutations and other seven genes from S were completely attenuated in terms of virulence to ducks whereas all recombinant viruses carrying HA gene from Y with same mutations and other seven genes from Y gained significant virulence. It seems that the compatibility among eight genes might be an important factor for HA to exert its functions. Results indicated that the mutation at amino acid position 322 and deletion at 329 in HA cleavage site significantly influence the pathogenicity of S and Y viruses in mallard, the compatibility among eight genes also contribute to the pathogenicity of both viruses in mallard.

Several H6 subtype avian A influenza viruses were isolated from aquatic birds in some live bird markets when we surveyed the ecology of the influenza in East China for more than two years and identified by specific RT-PCR. In this paper, the hemagglutinin (HA) and neuraminidase (NA) gene of one representative virus named A/Duck/Yangzhou/233/ 2002 (H6N2) (Dk/YZ/233/02) had been sequenced. Phylogenetic analysis of the H6 gene sequences available in the Influenza Sequence Database showed that the Dk/YZ/233/02 viruse cluster together with Dk/HK/3461/99 (H6N1) and Ck/Taiwan/na3/98 (H6N1). Phylogenetic analysis of the N2 NA genes of Dk/YZ/233/02 revealed that the NA gene of Dk/YZ/233/02 had genetically close relationships with that of H9N2 viruses isolated from duck in Japan and from chickens in South Korea, which were distinct from those of Ck/Beijing/94 (H9N2). The sequence of cleavage site between HA1 and HA2 of Dk/YZ/233/02 is P-Q-I-E-T-R-D, which was the typical characterization of the LPAIV.

Aim: To prepare monoclonal antibodies (mAb) against the hemagglutinin(HA) of H9 subtype of avian influenza virus (AIV)., Methods: 8 week-old female BALB/c mice were immunized with the inactivated vaccine of H9 subtype of AIV. Splenocytes from the immunized mice were fused with Sp2/0 myeloma cells, and positive hybridoma clones were screened by indirect ELISA and hemagglutination inhibition test (HI). The specificity of the mAb was characterized by ELISA, HI test, indirect immunofluorescence (IF) staining and Western blot., Results: Three hybridoma cell lines named 2H1, 2A3 and 1C8 against HA of AIV H9 were obtained. The HI titers of 3 mAbs were 1 x 2(8)-1 x 2(13), and the ELISA titers were 1 x 10(-7), 1 x 10(-5) and 5 x 10(-6), respectively. The immunoglobulin subclass of all 3 mAbs was IgG1. Western blot analysis confirmed that mAb 2H1 could recognize HA and reacted to 31 out of 32 isolates of H9 subtype of AIV., Conclusion: Three mAbs recognizing HA of H9 subtype of AIV were obtained, which may provide an useful tool for the antigenic analysis, the serological diagnosis, the epidemiological survey and the evaluation of AIV vaccine.