CD81/CD9 tetraspanins aid plasmacytoid dendritic cells in recognition of HCV-infected cells and induction of IFNα

Recognition of hepatitis C virus (HCV)-infected hepatocyes and interferon (IFN) induction are critical in antiviral immune response. We hypothesized that cell-cell contact between pDCs and HCV-infected cells was required for IFNα induction via involvement of cell surface molecules. Co-culture of human peripheral blood mononuclear cells (PBMCs) with genotype 1a full length HCV genomic replicon cells (FL) or genotype 2a JFH-1 virus infected hepatoma cells (JFH-1), not with uninfected hepatoma cells (Huh7.5), induced IFNα production. Depletion of pDCs from PBMCs attenuated IFNα release and purified pDCs produced high levels of IFNα after co-culture with FL replicons or JFH-1 infected cells. IFNα induction by HCV-containing hepatoma cells required viral replication, direct cell-cell contact with pDCs, and receptor-mediated endocytosis. We determined that the tetraspanin proteins, CD81 and CD9 and not other HCV entry receptors were required for IFNα induction in pDCs by HCV infected hepatoma cells. Disruption of cholesterol-rich membrane microdomains, the localization site of CD81 or inhibition of CD81 downstream molecule, Rac GTPase, inhibited IFNα production from co-cultures. IFNα production by HCV infected hepatoma cells was decreased in pDCs from HCV infected patients compared to normal controls. We found that pre-exposure of normal PBMCs to HCV viral particles attenuated IFNα induction by HCV infected hepatoma cells or TLR ligands and this inhibitory effect could be prevented by an anti-HCV E2 blocking antibody. In conclusion, our novel data show that recognition of HCV-infected hepatoma cells by pDCs involves CD81/CD9-associated membrane microdomains and induces potent IFNα production

A Review: Solder Joint Cracks at Sn-Bi58 Solder ACFs Joints

In this chapter, solder joint cracks at Sn-Bi58 solder ACF joints were investigated in conventional thermal compression bonding and ultrasonic bonding. It was found that resin storage modulus is the crucial for solder joint morphology regardless of bonding pressures. At high temperature, polymer resin tends to rebound above Tg and break the molten solder morphology. We proposed two useful methods to keep off solder joints cracks during bonding process. One is to remain bonding pressure until room temperature, the other is to use fillers to increase resin thermal mechanical property. The thermal cycling reliability was significantly enhanced when solder joint morphology was modified using 10 wt% 0.2 μm SiO2 fillers in acrylic based Sn-Bi58 solder ACF joints

Wetting and Brazing of YIG Ceramics Using Ag–CuO–TiO2 Metal Filler

The wetting and brazing of Y3Fe5O12 (YIG) ceramics with a Ag–8CuO–2TiO2 filler was investigated for the first time. For comparison, the wettability of a Ag–10CuO filler on YIG ceramics was similarly investigated. The Ag–8CuO–2TiO2 filler has an equilibrium contact angle of approximately 31 °C on the YIG substrate at 1000 °C; thus, its wettability is excellent. Moreover, its wettability exceeds that of Ag–10CuO. The microstructure and the interfacial structure between the filler and the substrate were determined using scanning electron microscopy, X-ray diffraction, EPMA and transmission electron microscopy. The liquid Ag–8CuO–2TiO2 filler can react with the YIG substrate by forming continuous Y2Ti2O7 layers with dotted CuFe2O4 and promote the wetting behavior and bonding performance. The average shear strength could exceed 30 MPa for the joints at a brazing temperature of 1000 °C. As rupture occurred adjacent to the seam at the ceramic side, the strengths of the interfaces were characterized via nanoindentation. The hardness of the interface with doped TiO2 exceeds that of Ag–10CuO, which is strengthened by the dotted CuFe2O4 among Y2Ti2O7

Crack propagation and strain-induced α’-martensite transformation in selective laser melting 316L stainless steels

At present, in-situ monitoring of metal cracking and propagation is still a challenge. In this work, we used in-situ tensile tests with precast cracks of selective laser melting (SLM) and conventionally manufactured (CM) 316L stainless steels (SSs) to study crack propagation and strain-induced α′-martensite transformation. During in-situ tensile, cracks initiate at the concentration of slip lines at the precast crack, and the strong stress at the crack tip will tear apart the grain boundaries causing the crack to propagate until the samples are completely fractured. After in-situ tensile, abnormal grain growth was observed in the plastic zone at the crack tip of the SLMed 316L SS sample, while austenite to α′-martensite transformation was appeared at the grain boundaries of the SLMed 316L SS sample, and martensitic patches generated by severe plastic deformation induced in the CM 316L SS were also observed. The SLMed 316L SS shows higher strength and resistance to deformation than CM 316L SS. In addition, the stress concentration at the crack tip in crack propagation has a significant effect on the transformation of strain-induced α′-martensite

Effects of Voltage-Gated K +

Objective. To study the effects and underlying mechanisms of voltage-gated K+ channels on the proliferation of multiple myeloma cells. Methods. RPMI-8226 MM cell line was used for the experiments. Voltage-gated K+ currents and the resting potential were recorded by whole-cell patch-clamp technique. RT-PCR detected Kv channel mRNA expression. Cell viability was analyzed with MTT assay. Cell counting system was employed to monitor cell proliferation. DNA contents and cell volume were analyzed by flow cytometry. Results. Currents recorded in RPMI-8226 cells were confirmed to be voltage-gated K+ channels. A high level of Kv1.3 mRNA was detected but no Kv3.1 mRNA was detected in RPMI-8226 cells. Voltage-gated K+ channel blocker 4-aminopyridine (4-AP) (2 mM) depolarized the resting potential from −42 ± 1.7 mV to −31.8 ± 2.8 mV (P<0.01). The results of MTT assay showed that there was no significant cytotoxicity to RPMI-8226 cells when the 4-AP concentration was lower than 4 mM. 4-AP arrested cell cycle in G0/G1 phase. Cells were synchronized at the G1/S boundary by treatment of aphidicolin and released from the blockage by replacing the medium with normal culture medium or with culture medium containing 2 mM 4-AP. 4-AP produced no significant inhibitory effect on cell cycle compared with control cells (P>0.05). Conclusions. In RPMI-8226, voltage-gated K+ channels are involved in proliferation and cell cycle progression its influence on the resting potential and cell volume may be responsible for this process; the inhibitory effect of the voltage-gated K+ channel blocker on RPMI-8226 cell proliferation is a phase-specific event

Expanding the Landscape of Chromatin Modification (CM)-Related Functional Domains and Genes in Human

Chromatin modification (CM) plays a key role in regulating transcription, DNA replication, repair and recombination. However, our knowledge of these processes in humans remains very limited. Here we use computational approaches to study proteins and functional domains involved in CM in humans. We analyze the abundance and the pair-wise domain-domain co-occurrences of 25 well-documented CM domains in 5 model organisms: yeast, worm, fly, mouse and human. Results show that domains involved in histone methylation, DNA methylation, and histone variants are remarkably expanded in metazoan, reflecting the increased demand for cell type-specific gene regulation. We find that CM domains tend to co-occur with a limited number of partner domains and are hence not promiscuous. This property is exploited to identify 47 potentially novel CM domains, including 24 DNA-binding domains, whose role in CM has received little attention so far. Lastly, we use a consensus Machine Learning approach to predict 379 novel CM genes (coding for 329 proteins) in humans based on domain compositions. Several of these predictions are supported by very recent experimental studies and others are slated for experimental verification. Identification of novel CM genes and domains in humans will aid our understanding of fundamental epigenetic processes that are important for stem cell differentiation and cancer biology. Information on all the candidate CM domains and genes reported here is publicly available