Transfer-Free Growth of Atomically Thin Transition Metal Disulfides Using a Solution Precursor by a Laser Irradiation Process and Their Application in Low-Power Photodetectors.

Although chemical vapor deposition is the most common method to synthesize transition metal dichalcogenides (TMDs), several obstacles, such as the high annealing temperature restricting the substrates used in the process and the required transfer causing the formation of wrinkles and defects, must be resolved. Here, we present a novel method to grow patternable two-dimensional (2D) transition metal disulfides (MS2) directly underneath a protective coating layer by spin-coating a liquid chalcogen precursor onto the transition metal oxide layer, followed by a laser irradiation annealing process. Two metal sulfides, molybdenum disulfide (MoS2) and tungsten disulfide (WS2), are investigated in this work. Material characterization reveals the diffusion of sulfur into the oxide layer prior to the formation of the MS2. By controlling the sulfur diffusion, we are able to synthesize continuous MS2 layers beneath the top oxide layer, creating a protective coating layer for the newly formed TMD. Air-stable and low-power photosensing devices fabricated on the synthesized 2D WS2 without the need for a further transfer process demonstrate the potential applicability of TMDs generated via a laser irradiation process.

The methylation patterns of a disintegrin and metalloproteinase 33 gene (ADAM33) in adult asthma.

BACKGROUND: Asthma is a common chronic inflammatory respiratory disease. Previous studies have suggested that the pathogenesis of asthma may be affected by epigenetic regulation. The purpose of this study is to characterize the effect of the methylation of each CpG site in the ADAM33 (a disintegrin and metalloproteinase 33) gene in adult asthma. METHODS: A human CpG island microarray was used to examine 4 asthmatic cases and 4 healthy controls, and the results suggested that there might be differences in methylation within exon 9 of the ADAM33 gene. Therefore, we designed a case-control study with 50 asthmatic patients and 50 age- and sex-matched healthy controls to examine the relationship between the CpG methylation of the ADAM33 gene and asthma using bisulfite deoxyribonucleic acid modification and sequencing. RESULTS: Bisulfite sequencing experiments showed that the 14 CpG sites in exon 9 of the ADAM33 gene were highly methylated (100%) in all individuals. The proportions of methylation of the 14 CpG sites in ADAM33 in the case group were not different from those of the control group. The methylation of exon 9 of this locus was not associated with age, sex, IgE levels, or lung function. This study found no association between the methylation of CpG sites in exon 9 of the ADAM33 gene and adult asthma. CONCLUSIONS: The 14 CpG sites were highly methylated in the case and control groups. Further investigation of exon 9 in ADAM33 in a larger population is needed to evaluate its role in asthma.

The association between adult asthma and superoxide dismutase and catalase gene activity.

BACKGROUND: Adult asthma is caused by interaction effects of multiple genetic and environmental factors. Some studies have suggested that antioxidant enzyme activity and gene polymorphisms may play important roles in the context of asthma. Therefore, our study objectives were to investigate the association between asthma, antioxidant activities and the polymorphisms of manganese superoxide dismutase (Mn-SOD) or catalase (CAT). MATERIALS AND METHODS: A case-control study, for which we recruited 250 asthmatic adults and 250 age- and sex-matched controls. All subjects completed a questionnaire. Waist and hip circumference measurements, a lung function test and DNA genotyping were performed. In total, 50 incident cases and 50 matched controls who were non-smokers or had quit smoking for at least 1 year were selected in order to investigate SOD and CAT activity levels. RESULTS: In our study, we did not find a significant association between Mn-SOD Ala16Val, CAT C-262T and asthma. The level of SOD activity in new-onset asthma patients was significantly lower than in control subjects (p < 0.0005). The level of CAT activity in new-onset asthma patients was significantly higher than in control subjects (p < 0.0005). CONCLUSIONS: The levels of SOD and CAT activity were significantly related to adult asthma. SOD and CAT activity may be good tools to differentiate potential asthma sufferers. This would enable us to further investigate the mechanism of defective antioxidant enzymes in the context of asthma pathogenesis.