Transition-Metal-Doped NIR-Emitting Silicon Nanocrystals

Impurity-doping in nanocrystals significantly affects their electronic properties and diversifies their applications. Herein, we report the synthesis of transition metal (Mn, Ni, Co, Cu)-doped oleophilic silicon nanocrystals (SiNCs) through hydrolysis/polymerization of triethoxysilane with acidic aqueous metal salt solutions, followed by thermal disproportionation of the resulting gel into a doped-Si/SiO2 composite that, upon HF etching and hydrosilylation with 1-n-octadecene, produces free-standing octadecyl-capped doped SiNCs (diameter approximate to 3 to 8 nm; dopant <0.2 atom %). Metal-doping triggers a red-shift of the SiNC photoluminescence (PL) of up to 270 nm, while maintaining high PL quantum yield (26% for Co doping).Peer reviewe

Synthesis and characterization of visible-light-driven novel CuTa2O6 as a promising practical photocatalyst

In this work, the novel CuTa2O6 phase was successfully synthesized by the hydrothermal and followed by the calcination process. The X-ray diffraction pattern confirms the formation of different phases. At a low temperature, CuTa2O6 exhibits the orthorhombic phase, whereas, at a higher temperature, it underwent a phase transition to a cubic crystal structure. X-ray photoelectron spectroscopic results suggest the presence of all the elements (Cu, Ta, and O). The optical studies were carried out using a UV-Vis DRS spectrophotometer. FESEM images confirm the spherical-shaped particles for the sample annealed at a high temperature. The local atomic and electronic structures around Cu and the contribution of the Cu oxidation state in the CuTa2O6 system were determined by X-ray absorption spectroscopy. To investigate the effective usage of CuTa2O6 in treating wastewater, its photocatalytic activity was investigated by evaluating its use in the photodegradation of MO dye under visible light irradiation. Moreover, the prepared CuTa2O6 photocatalyst exhibits significant photocatalytic activity in the degradation of MO dye and shows excellent stability; it is therefore a promising material for potential use in a practical photocatalyst. The CuTa2O6 photocatalyst suggests an alternative avenue of research into effective photo-catalysts for solar hydrogen water splitting

Defining the Role of the MHC in Autoimmunity: A Review and Pooled Analysis

The major histocompatibility complex (MHC) is one of the most extensively studied regions in the human genome because of the association of variants at this locus with autoimmune, infectious, and inflammatory diseases. However, identification of causal variants within the MHC for the majority of these diseases has remained difficult due to the great variability and extensive linkage disequilibrium (LD) that exists among alleles throughout this locus, coupled with inadequate study design whereby only a limited subset of about 20 from a total of approximately 250 genes have been studied in small cohorts of predominantly European origin. We have performed a review and pooled analysis of the past 30 years of research on the role of the MHC in six genetically complex disease traits – multiple sclerosis (MS), type 1 diabetes (T1D), systemic lupus erythematosus (SLE), ulcerative colitis (UC), Crohn's disease (CD), and rheumatoid arthritis (RA) – in order to consolidate and evaluate the current literature regarding MHC genetics in these common autoimmune and inflammatory diseases. We corroborate established MHC disease associations and identify predisposing variants that previously have not been appreciated. Furthermore, we find a number of interesting commonalities and differences across diseases that implicate both general and disease-specific pathogenetic mechanisms in autoimmunity

Highly responsive diabetes and asthma sensors with WO3 nanoneedle films for the detection of biogases with low concentrations

Abstract A diabetes sensor was developed to detect low concentrations of acetone gas, which is a diabetes biomarker. A WO3 nanoneedle film was synthesized via an aqueous process for use as a sensitive sensing membrane. Acetone was adsorbed and oxidized on the WO3 nanoneedle film, which changed the sensor resistance. The sensor exhibited a high response of R a /R g  = 19.72, where R a is the sensor resistance in air, and R g is the sensor resistance in air containing 10 ppmv acetone gas. The sensor also exhibited a high response (25.36) to 1 ppmv NO2, which is related to asthma. Furthermore, the sensor responded to various biogases associated with diseases. The sensor responses to 10 ppmv of the lung cancer marker gases acetaldehyde and toluene were 13.54 and 9.49, respectively. The sensor responses to 10 ppmv isoprene, ethanol, para-xylene, hydrogen, and NH3 were 7.93, 6.33, 4.51, 2.08, and 0.90, respectively. Trace amounts of acetone and NO2 gases (25 and 250 ppbv, respectively) were detected. The limits of detection for acetone and NO2 gases were estimated to be 2.4 and 1.5 ppbv, respectively. The sensor exhibited superior ability to detect low concentrations of biomarker gases. The unique characteristics of the WO3 nanoneedle film contributed to its high response rates