Template Route to Chemically Engineering Cavities at Nanoscale: A Case Study of Zn(OH)2 Template

A size-controlled Zn(OH)2 template is used as a case study to explain the chemical strategy that can be executed to chemically engineering various nanoscale cavities. Zn(OH)2 octahedron with 8 vertices and 14 edges is fabricated via a low temperature solution route. The size can be tuned from 1 to 30 μm by changing the reaction conditions. Two methods can be selected for the hollow process without loss of the original shape of Zn(OH)2 template. Ion-replacement reaction is suitable for fabrication of hollow sulfides based on the solubility difference between Zn(OH)2 and products. Controlled chemical deposition is utilized to coat an oxide layer on the surface of Zn(OH)2 template. The abundant hydroxyl groups on Zn(OH)2 afford strong coordination ability with cations and help to the coating of a shell layer. The rudimental Zn(OH)2 core is eliminated with ammonia solution. In addition, ZnO-based heterostructures possessing better chemical or physical properties can also be prepared via this unique templating process. Room-temperature photoluminescence spectra of the heterostructures and hollow structures are also shown to study their optical properties

Mapping the lectin-like activity of tumor necrosis factor

Tumor necrosis factor (TNF), but not lymphotoxin (LT), is directly trypanolytic for salivarian trypanosomes. This activity was not blocked by soluble 55-kilodalton and 75-kilodalton TNF receptors, but was potently inhibited by N,N'-diacetylchitobiose, an oligosaccharide that binds TNF. Comparative sequence analysis of TNF and LT localized the trypanocidal region, and synthetic peptides were trypanolytic. TNF molecules in which the trypanocidal region was mutated or deleted retained tumoricidal activity. Thus, trypanosome-TNF interactions occur via a TNF domain, probably with lectin-like affinity, which is functionally and spatially distinct from the mammalian TNF receptor binding sites

Genotyping Hepatitis C Viruses from Southeast Asia by a Novel Line Probe Assay That Simultaneously Detects Core and 5′ Untranslated Regions

Hepatitis C viruses (HCVs) display a high level of sequence diversity and are currently divided into six genotypes. A line probe assay (LiPA), which targets the 5′ untranslated region (5′UTR) of the HCV genome, is widely used for genotyping. However, this assay cannot distinguish many genotype 6 subtypes from genotype 1 due to high sequence similarity in the 5′UTR. We investigated the accuracy of a new generation LiPA (VERSANT HCV genotype 2.0 assay), in which genotyping is based on 5′UTR and core sequences, by testing 75 selected HCV RNA-positive sera from Southeast Asia (Vietnam and Thailand). For comparison, sera were tested on the 5′UTR based VERSANT HCV genotype assay and processed for sequence analysis of the 5′UTR-to-core and NS5b regions as well. Phylogenetic analysis of both regions revealed the presence of genotype 1, 2, 3, and 6 viruses. Using the new LiPA assay, genotypes 6c to 6l and 1a/b samples were more accurately genotyped than with the previous test only targeting the 5′UTR (96% versus 71%, respectively). These results indicate that the VERSANT HCV genotype 2.0 assay is able to discriminate genotypes 6c to 6l from genotype 1 and allows a more accurate identification of genotype 1a from 1b by using the genotype-specific core information