Review and Mechanism of the Thickness Effect of Solid Dielectrics.

The thickness effect of solid dielectrics means the relation between the electric breakdown strength (EBD) and the dielectric thickness (d). By reviewing different types of expressions of EBD on d, it is found that the minus power relation (EBD = E1d-a) is supported by plenty of experimental results. The physical mechanism responsible for the minus power relation of the thickness effect is reviewed and improved. In addition, it is found that the physical meaning of the power exponent a is approximately the relative standard error of the EBD distributions in perspective of the Weibull distribution. In the end, the factors influencing the power exponent a are discussed.

Phosphodiesterase 4 Inhibitor Roflumilast Protects Rat Hippocampal Neurons from Sevoflurane Induced Injury via Modulation of MEK/ERK Signaling Pathway.

BACKGROUND/AIMS: Sevoflurane, a commonly used volatile anesthetic, recently has been found has neurotoxicity in the central nervous system of neonatal rodents. This study aimed to reveal whether phosphodiesterase 4 (PDE-4) inhibitor roflumilast has protective functions in sevoflurane-induced nerve damage. METHODS: Hippocampal neurons were isolated from juvenile rats, and were exposed to sevoflurane with or without roflumilast treatment. Cell viability and apoptosis were respectively assessed by CCK-8 and flow cytometry. Western blot analysis was performed to detect the protein expressions of apoptosis-related factors, and core factors in MEK/ERK and mTOR signaling pathways. RESULTS: Toxic effects of sevoflurane on hippocampal neurons were observed, as cell viability was reduced, apoptotic cell rate was increased, Bcl-2 was down-regulated, and Bax, cleaved caspase-3 and -9 were up-regulated after 1% sevoflurane exposure for 16 h. Sevoflurane exhibited a temporarily (less than 16 h) inhibitory effect on MEK/ERK pathway, but has no impact on mTOR pathway. Roflumilast promoted the release of cAMP and down-regulated the protein expression of PDE-4. Roflumilast (1 µM) alone has no impact on viability and apoptosis of hippocampal neurons. However, roflumilast increased cell viability and deceased apoptosis in sevoflurane-injured neurons. Besides, roflumilast could recover sevoflurane-induced deactivation of MEK/ERK pathway. CONCLUSION: To conclude, this study demonstrated a neuroprotective role of roflumilast in sevoflurane-induced nerve damage. Roflumilast promoted hippocampal neurons viability, and reduced apoptosis possibly via modulation of MEK/ERK signaling pathway.

Chemical constituents from Periplaneta Americana / 中成药

AIM To study the chemical constituents from P.americana L..METHODS The 90％ ethanol extract from P.americana was isolated and purified by silica,ODS,Sephadex LH-20,then the structures of obtained compounds were identified by physicochemical properties and spectral data.RESULTS Sixteen compounds were isolated and identified as L-leucine (1),uracil (2),acetamide (3),valine (4),γ-aminobutyric acid (5),glycerol (6),methyl,2-piperidinecarboxylate (7),pyrazine (8),protocatechuic acid-4-O-β-D-glucopyranoside (9),thymidine (10),cyclo (Pro-Ser) (11),cyclo (Pro-Asn) (12),phenylalanine (13),4-(2-aminoethyl) benzene-1,2-diol (14),inosine (15),tyramine (16).CONCLUSION Compounds 3,7-12,14,16 are all isolated from Periplaneta americana and genus Periplaneta for the first time.

[Effects of Compound Aconitum Polysaccharide on Glycosylation of Tumor Cells].

Objective To observe inducing or inhibiting effects of Chinese medicine (CM) poly- saccharides on glycoprotein chain synthetized different glycosyltransferases, thus disclosing targets of CM polysaccharides and its mechanisms. Methods In vivo anti-tumor effects of CM polysaccharides were observed using the inhibiting rate of tumor growth by dividing different Aconitum containing groups. Effects of CM polysaccharides on liver cancer cell SK-HEP-1 glycosyltransferase and tumor related gene expressions were observed. Meanwhile, changes of polylactosamine expression were detected using flow cytometry (FCM) with polylactosamine specific biotin labeling lectin. Results Compared with the model group, the average tumor weight was significantly lower in each medication group (P <0. 01). Compared with the adriamycin group, no significant difference in average tumor weight of the three compound groups (P>0. 05). The expression level of polylactosamine was reduced after adding Aconitum polysac- charide; and CM compound polysaccharides respectively. Conclusions Polysaccharide compound showed similar anti-tumor effect as that of adriamycin. Besides, polylactosamine expression level was reduced in the three compound groups along with increased prepared Aconitum polysaccharide, with more obvious anti-tumor effects shown.

Ambiguity-free edge-bundling for interactive graph visualization.

Graph visualization has been widely used to understand and present both global structural and local adjacency information in relational data sets (e.g., transportation networks, citation networks, or social networks). Graphs with dense edges, however, are difficult to visualize because fast layout and good clarity are not always easily achieved. When the number of edges is large, edge bundling can be used to improve the clarity, but in many cases, the edges could be still too cluttered to permit correct interpretation of the relations between nodes. In this paper, we present an ambiguity-free edge-bundling method especially for improving local detailed view of a complex graph. Our method makes more efficient use of display space and supports detail-on-demand viewing through an interactive interface. We demonstrate the effectiveness of our method with public coauthorship network data.

[Preparation and application of polyclonal antibody against mouse IL-1α].

AIM: To construct a recombinant plasmid encoding mouse IL-1α (mIL-1α), express and purify mIL-1α protein, and prepare its polyclonal antibody. METHODS: The cDNAs were obtained from the spleen cells of BALB/c mice and the full length of mIL-1α gene was amplified by RT-PCR. Then the mIL-1α gene was inserted into a prokaryotic expression vector pET32a(+) and the resulting recombinant plasmid was transformed into E.coli BL21(DE3). After auto-induction, the mIL-1α protein was expressed and purified by electro-elution. An anti-mIL-1α polyclonal antibody was raised in New Zealand rabbits after immunization with the purified mIL-1α and the titer was determined by ELISA. The specificity of the polyclonal antibody was identified by Western blot and flow cytometry. RESULTS: The recombinant prokaryotic expression vector pET32a(+)-IL-1α was successfully constructed, and the mIL-1α protein was expressed and purified. ELISA showed the titer of the anti-mIL-1α serum was 1:25 600. Western blot and flow cytometry demonstrated the high specificity of the polyclonal antibody to IL-1α. CONCLUSION: The rabbit anti-mIL-1α polyclonal antibody with high titer and specificity has been prepared after immunization with the purified mIL-1α protein, facilitating further functional studies of IL-1α.

Asymmetric Michael addition of trisubstituted carbanion to nitroalkenes catalyzed by sodium demethylquinine salt in water.

A mild method for the asymmetric synthesis of quaternary and tertiary carbon centers has been developed through Michael addition of trisubstituted carbon nucleophile to nitroalkenes catalyzed by low loading sodium demethylquinine salt in water.