RESUMO
Liquid metals, such as Ga and eutectic Ga-In, have been extensively studied for various applications, including flexible and wearable devices. For applying liquid metal to electronic devices, interconnection with the various metal electrodes currently in use, and verifying their mechanical reliability are essential. Here, detailed investigations of the formation and growth of intermetallic compounds (IMCs) during the reactions between liquid Ga and solid nickel were conducted. Ga and Ni were reacted at 250, 300, and 350 °C for 10-240 min. The IMC double layer observed after the reactions contained a Ga7Ni3 bottom layer formed during the reactions, and a GaxNi top layer (with 89-95 at.% of Ga) precipitated during cooling. Numerous empty channels exist between the rod-type Ga7Ni3 IMCs. Ga7Ni3 growth occurred only in the vertical direction, without lateral coarsening and merging between the rods. The time exponents were measured at 1.1-1.5, implying that the reaction kinetics were near-interface reaction-controlled. The activation energy for Ga7Ni3 growth was determined as 49.1 kJ/mol. The experimental results of the Ga-Ni reaction study are expected to provide important information for incorporating liquid metals into electronic devices in the future.
RESUMO
Epidermal growth factorlike domain 8 (EGFL8), a newly identified member of the EGFL family, and plays negative regulatory roles in mouse thymic epithelial cells (TECs) and thymocytes. However, the role of EGFL8 in these cells remains poorly understood. In the present study, in order to characterize the function of EGFL8, genomewide expression profiles in EGFL8overexpressing or silenced mouse cortical TECs (cTECs) were analyzed. Microarray analysis revealed that 458 genes exhibited a >2fold change in expression levels in the EGFL8overexpressing vs. the EGFL8silenced cTECs. Several genes involved in a number of cellular processes, such as the cell cycle, proliferation, growth, migration and differentiation, as well as in apoptosis, reactive oxygen species generation, chemotaxis and immune responses, were differentially expressed in the EGFL8overexpressing or silenced cTECs. WST1 analysis revealed that that the overexpression of EGFL8 inhibited cTEC proliferation. To investigate the underlying mechanisms of EGFL8 in the regulation of cTEC function, genes related to essential cellular functions were selected. Reverse transcriptionpolymerase chain reaction analysis revealed that EGFL8 knockdown upregulated the expression of cluster differentiation 74 (CD74), Fas ligand (FasL), CXC motif chemokine ligand 5 (CXCL5), CXCL10, CXCL16, CC motif chemokine ligand 20 (CCL20), vascular endothelial growth factorA (VEGFA), interferon regulatory factor 7 (Irf7), insulinlike growth factor binding protein4 (IGFBP4), thrombospondin 1 (Thbs1) and nuclear factor κB subunit 2 (NFκB2) genes, and downregulated the expression of angiopoietinlike 1 (Angptl1), and neuropilin1 (Nrp1) genes. Additionally, EGFL8 silencing enhanced the expression of antiapoptotic molecules, such as Bcell lymphoma2 (Bcl2) and Bclextra large (BclxL), and that of cell cycleregulating molecules, such as cyclindependent kinase 1 (CDK1), CDK4, CDK6 and cyclin D1. Moreover, gene network analysis revealed that EGFL8 exerted negative effects on VEGFA gene expression. Hence, the altered expression of several genes associated with EGFL8 expression in cTECs highlights the important physiological processes in which EGFL8 is involved, and provides insight into its biological functions.
Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Família de Proteínas EGF/metabolismo , Células Epiteliais/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Timo/metabolismo , Animais , Proteínas de Ligação ao Cálcio/genética , Linhagem Celular , Família de Proteínas EGF/genética , Células Epiteliais/citologia , Camundongos , Timo/citologiaRESUMO
Carbon-encapsulated hollow porous vanadium-oxide (C/HPV2O5) nanofibers have been fabricated using electrospinning and postcalcination. By optimized postcalcination of vanadium-nitride and carbon-nanofiber composites at 400 °C for 30 min, we synthesized a unique architecture electrode with interior void spaces and well-defined pores as well as a uniform carbon layer on the V2O5 nanofiber surface. The optimized C/HPV2O5 electrode postcalcined at 400 °C for 30 min showed improved lithium storage properties with high specific discharge capacities, excellent cycling durability (241 mA h g(-1) at 100 cycles), and improved high-rate performance (155 mA h g(-1) at 1000 mA g(-1)), which is the highest performance in comparison with previously reported V2O5-based cathode materials. The improved electrochemical feature is due to the attractive properties of the carbon-encapsulated hollow porous structure: (I) excellent cycling durability with high specific capacity relative to the adoption of carbon encapsulation as a physical buffer layer and the effective accommodation of volume changes due to the hollow porous structure, (II) improved high-rate performance because of a shorter Li-ion diffusion pathway resulting from interior void spaces and well-defined pores at the surface. This unique electrode structure can potentially provide new cathode materials for high-performance lithium-ion batteries.
RESUMO
Recombinant adeno-associated virus (rAAV) vectors encoding human factor VIII (hFVIII) were systematically evaluated for hemophilia A (HA) gene therapy. A 5.7-kb rAAV-expression cassette (rAAV-HLP-codop-hFVIII-N6) containing a codon-optimized hFVIII cDNA in which a 226 amino acid (aa) B-domain spacer replaced the entire B domain and a hybrid liver-specific promoter (HLP) mediated 10-fold higher hFVIII levels in mice compared with non-codon-optimized variants. A further twofold improvement in potency was achieved by replacing the 226-aa N6 spacer with a novel 17-aa peptide (V3) in which 6 glycosylation triplets from the B domain were juxtaposed. The resulting 5.2-kb rAAV-HLP-codop-hFVIII-V3 cassette was more efficiently packaged within AAV virions and mediated supraphysiologic hFVIII expression (732 ± 162% of normal) in HA knock-out mice following administration of 2 × 10(12) vector genomes/kg, a vector dose shown to be safe in subjects with hemophilia B. Stable hFVIII expression at 15 ± 4% of normal was observed at this dose in a nonhuman primate. hFVIII expression above 100% was observed in 3 macaques that received a higher dose of either this vector or the N6 variant. These animals developed neutralizing anti-FVIII antibodies that were abrogated with transient immunosuppression. Therefore, rAAV-HLP-codop-hFVIII-V3 substantially improves the prospects of effective HA gene therapy.
Assuntos
Dependovirus/genética , Fator VIII/farmacologia , Terapia Genética , Variação Genética/genética , Vetores Genéticos/administração & dosagem , Hemofilia A/terapia , Animais , Western Blotting , Fator VIII/genética , Fator VIII/imunologia , Glicosilação , Hemofilia A/genética , Humanos , Tolerância Imunológica , Fígado/metabolismo , Macaca mulatta , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Regiões Promotoras Genéticas/genéticaRESUMO
Comet assays were carried out to evaluate DNA damage in T- and B-lymphocytes and granulocytes from 41 workers exposed to benzene in a printing company and 41 unexposed donors. In T-lymphocytes, DNA damage was slightly higher in exposed workers than in controls. The tail moments in the two groups were 1.75+/-0.29 and 1.47+/-0.41, respectively (P<0.0006). DNA damage of B-lymphocytes in the two groups showed the most significant difference among the three cell types. The tail moments were 3.86+/-0.71 and 1.51+/-0.39, respectively (P<0.0001). In granulocytes, DNA damage was also different, the tail moments being 3.61+/-0.75 and 2.60+/-0.59, respectively (P<0.0001). The comparison of DNA damage in both groups shows that B-lymphocytes could be a useful target in biomonitoring of human exposure to low levels of benzene.