Two-dimensional (2D) transition-metal dichalcogenide alloys with tunable band gaps have promising applications in nanoelectronics and optoelectronics. Characterization of structures of 2D alloys, such as composition and atom mixing, is of fundamental importance to their applications. Here, we have conducted systematic Raman spectroscopic studies on Mo1-xWxS2 monolayers (0 ≤x≤ 1). First-order Raman modes and second-order Raman modes have been observed in the range of 100-480 cm(-1) in the 2D alloys. The out-of-plane A1' modes and in-plane E' modes showed one-mode and two-mode behaviors, respectively. The broadening of A1' and E' modes in the alloys has been observed. The disorder-related Raman peaks at ∼360 cm(-1) were only observed in the 2D alloys but not in the two end materials. Modified random-element-isodisplacement (MREI) model has been adopted to successfully predict mode behaviors of A1' and E' modes in the monolayer alloys. Further, composition-dependent A1' and E' frequencies can be well fitted by the MREI model, giving composition-dependent force constants.

1) Quercetin has a higher reduction potential compared with curcumin at three different pH settings and is comparable to Trolox at pH 7-9.5; 2) its TAC is 3.5 fold higher than curcumin; 3) it reduced LPS-induced ROS to near normal levels; 4) it reduced LPS-induced NO production. These data provide a physico-chemical basis for comparing antioxidants, with potential benefits individually or in combination.

Short-term stimulation of the P2X(7) receptor can raise Ca(2+) in rat retinal ganglion cells, whereas sustained stimulation of the receptor can kill them.

Inositolsphingolipid phospholipase C (Isc1p) is theCeramide is a bioactive lipid that in eukaryotic cells functions as a mediator of a variety of extracellular signals through the regulation of several downstream effectors which in turn control basic cellular functions such as cell growth, cell cycle arrest, apoptosis, and senescence (1-6). Sphingomyelinases, which hydrolyze the phosphodiester linkage of sphingomyelin (SM) 1 to produce ceramide and phosphorylcholine, function as key regulators of the intracellular levels of ceramide in mammalian cells.Sphingolipids are also important regulatory molecules in yeast where they are known to be required for viability (7), optimal life span (8), cell cycle regulation (9), endocytosis (10), and regulation of responses of yeast cells to stress (1, 11). Although Saccharomyces cerevisiae do not contain SM, they do contain inositol phosphoceramides, and recently we identified a homologue of neutral sphingomyelinase in S. cerevisiae, Isc1p, which acts on phosphoceramides to generate ceramide. This enzyme displays ϳ30% identity to neutral sphingomyelinase 2 and shares with it several common features (12) including hydrolytic activity on SM, the requirement of Mg 2ϩ for optimal activity, optimal neutral pH, and the presence of a newly discovered domain that is conserved in the entire family of sphingomyelinases, the P-loop-like domain (13), which appears to be important for substrate binding and/or catalysis.In addition, both enzymes demonstrate an absolute requirement for anionic phospholipids for in vitro activation. Thus, Isc1p is activated selectively in vitro by cardiolipin (CL), phosphtidylglycerol (PG), or phosphatidylserine. In a recent study we demonstrated that the enzyme binds these anionic phospholipids, and we identified the second transmembrane domain and the C terminus of Isc1p as required for this binding, and it was proposed that this interaction plays a critical role in enzyme function through a novel tethering mechanism of enzyme activation by lipid cofactors (14).Given these specific requirements for anionic phospholipids in vitro, it became important to determine whether the enzyme requires phospholipids for activation in vivo. Our attention was particularly directed to the possible roles of PG and CL as the deletion of PGS1, the gene that encodes the enzyme responsible for the synthesis of PG phosphate, and subsequent synthesis of PG and CL was shown to cause a late defect during growth in glucose media similar to that of ISC1. Moreover, these lipids are almost exclusively present in mitochondria, and we have shown recently that Isc1p localizes preferentially to mitochondria in the post-diauxic phase of growth.Synthesis of CL in yeast requires three sequential reactions.

Background Frequent premature ventricular contractions (PVCs) are associated with increased risk for sudden cardiac death (SCD) and can cause secondary cardiomyopathy (CM). Objective We sought to determine the mechanism(s) responsible for prolonged refractory period and LV dysfunction demonstrated in our canine model of PVC-induced CM. Methods Single myocytes were isolated from LV free wall of PVC and control canines, and used for patch clamp recording, [Ca]i measurements and immunocytochemistry/confocal microscopy. LV tissues adjacent to area of myocyte isolation were used for immunoblot quantification of protein expression. Results In PVC group, LVEF declined from 57.6±1.5% to 30.4±3.1% after ≥ 4 months of ventricular bigeminy. Compared to control myocytes, PVC myocytes had reduced densities of both outward (Ito and IK1) and inward (ICaL) currents, but no consistent changes in IKr or IKs. The reduction in Ito, IK1 and ICaL was accompanied by decreased protein levels of their channel subunits. The degrees of reduction in Ito, IK1 and ICaL varied among PVC myocytes, creating marked heterogeneity in action potential (AP) configurations and durations. PVC myocytes showed impaired Ca-induced Ca release from SR, without increase in SR Ca leak or decrease in SR Ca store. This was accompanied by a decrease in dyad scaffolding protein, junctophilin-2, and loss of Cav1.2 registry with Ca-releasing channels (RyR2). Conclusion PVCs increase dispersion of AP configuration/duration, a risk factor for SCD, due to heterogeneous reduction in Ito, IK1 and ICaL. The E-C coupling is impaired due to decrease in ICaL and Cav1.2 misalignment with respect to RyR2.

AimsTo determine infant exposure to 6-thioguanine and 6-methylmercaptopurine nucleotides (6-TGN and 6-MMPN, respectively) during maternal use of azathioprine in breastfeeding. MethodsMother-infant pairs provided blood for determination of 6-TGN and 6-MMPN concentrations, and TPMT genotype.

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