Design Guidelines for Two-Dimensional Transition Metal Dichalcogenide Alloys.

Two-dimensional (2D) materials and transition metal dichalcogenides (TMD) in particular are at the forefront of nanotechnology. To tailor their properties for engineering applications, alloying strategies-used successfully for bulk metals in the last century-need to be extended to this novel class of materials. Here we present a systematic analysis of the phase behavior of substitutional 2D alloys in the TMD family on both the metal and the chalcogenide site. The phase behavior is quantified in terms of a metastability metric and benchmarked against systematic computational screening of configurational energy landscapes from First-Principles. The resulting Pettifor maps can be used to identify broad trends across chemical spaces and as starting point for setting up rational search strategies in phase space, thus allowing for targeted computational analysis of properties on likely thermodynamically stable compounds. The results presented here also constitute a useful guideline for synthesis of binary metal 2D TMDs alloys via a range of synthesis techniques.

Pressure-Induced Superconductivity in HgTe Single-Crystal Film.

HgTe film is widely used for quantum Hall well studies and devices, as it has unique properties, like band gap inversion, carrier-type switch, and topological evolution depending on the film thickness modulation near the so-called critical thickness (63.5 Å), while its counterpart bulk materials do not hold these nontrivial properties at ambient pressure. Here, much richer transport properties emerging in bulk HgTe crystal through pressure-tuning are reported. Not only the above-mentioned abnormal properties can be realized in a 400 nm thick bulk HgTe single crystal, but superconductivity is also discovered in a series of high-pressure phases. Combining crystal structure, electrical transport, and Hall coefficient measurements, a p-n carrier type switching is observed in the first high-pressure cinnabar phase. Superconductivity emerges after the semiconductor-to-metal transition at 3.9 GPa and persists up to 54 GPa, crossing four high-pressure phases with an increased upper critical field. Density functional theory calculations confirm that a surface-dominated topologic band structure contributes these exotic properties under high pressure. This discovery presents broad and efficient tuning effects by pressure on the lattice structure and electronic modulations compared to the thickness-dependent critical properties in 2D and 3D topologic insulators and semimetals.

Molecular mechanisms by which casein glycomacropeptide maintains internal homeostasis in mice with experimental ulcerative colitis.

OBJECTIVES: The aim of this study was to elucidate the molecular mechanisms by which food-derived casein glycomacropeptide (CGMP) maintains internal homeostasis in the intestinal mucosa and to investigate the effects of CGMP on the intestinal mucosal immunological barrier and related signal transduction pathways. METHODS: In this study, a famoxadone (OXZ)-induced mouse experimental ulcerative colitis (UC) model was built. The experimental UC mice were intragastrically administered milk-derived CGMP for four consecutive days. The molecular mechanisms by which milk-derived CGMP improved and restored the inflammatory status in UC symptoms were elucidated by H&E staining, immunohistochemical staining and western blotting. RESULTS: The results indicated that CGMP (50 mg/(kg bw·d)) could significantly improve morphological injury to intestinal mucosa in OXZ-induced UC mice to the same extent that did sulfasalazine (SASP, 40 mg/(kg bw·d)), a medicine used to treat UC, in the control group. The study found that CGMP could significantly reduce the expression of Human mucosal addressin cell adhesion molecule-1 (MAdCAM-1), Cluster of differentiation 4 (CD4) and Cluster of differentiation 8 (CD8) in the lamina propria of the intestinal mucosa and significantly stimulate the secretion of sIgA to increase intestinal immunity. Furthermore, CGMP was found to be directly involved in inhibiting the MAPK pathway and activating the TGF-ß1/Smad signal transduction cascade, which could maintain immunological regulation of the intestinal mucosa and protect the functions of the intestinal mucosal barrier. CONCLUSIONS: This study elucidated the molecular mechanisms by which CGMP maintained homeostasis of the intestinal mucosa and further confirmed its pharmaceutical value as a food-derived functional component with promising potential for further exploration/utilization.

Helical Polyisocyanopeptides as Lyotropic Liquid Crystals for Measuring Residual Dipolar Couplings.

Residual dipolar couplings (RDC) emerged to be an important structural parameter for organic and biomolecules. Herein, a new helical polyisocyanopeptide (l,l-PIAF-OBn) that forms lyotropic liquid crystals (LLC) in CDCl3 is proposed as a novel weakly orienting medium for acquiring residual dipolar couplings (RDCs) of organic molecules. We demonstrate its application for the structural elucidation of strychnine and triptolide.

An Alignment Medium for Measuring Residual Dipolar Couplings in Pure DMSO: Liquid Crystals from Graphene Oxide Grafted with Polymer Brushes.

Residual dipolar couplings (RDCs) have attracted attention in light of their great impact on the structural elucidation of organic molecules. However, the effectiveness of RDC measurements is limited by the shortage of alignment media compatible with widely used organic solvents, such as DMSO. Herein, we present the first liquid crystal (LC) based alignment medium that is compatible with pure DMSO, thus enabling RDC measurements of polar and intermediate polarity molecules. The liquid crystals were obtained by grafting polymer brushes onto graphene oxide (GO) using free radical polymerization. The resulting new medium offers several advantages, such as absence of background signals, narrow line shapes, and tunable alignment. Importantly, this medium is compatible with π-conjugated molecules. Moreover, sonication-induced fragmentation can reduce the size of GO sheets. The resulting anisotropic medium has moderate alignment strength, which is a prerequisite for an accurate RDC measurement.

[Impact of atrial fibrillation on prognosis of chronic heart failure patients with left ventricular ejection fraction>or=0.5].

OBJECTIVE: To explore the prevalence, distribution type and impact of atrial fibrillation on prognosis of hospitalized patients with congestive heart failure (CHF) with left ventricular ejection fraction (LVEF)>or=0.50. METHODS: The medical records of 417 unselected consecutive patients with CHF were retrospectively reviewed. Patients were categorized as LVEF<0.50 or LVEF>or=0.50. And they were also categorized by the past history of atrial fibrillation and divided into three groups: paroxysmal atrial fibrillation, continuous atrial fibrillation and onset of atrial fibrillation after admission. Then the vicious events, the number of readmission due to CHF and the interval between discharge and readmission were observed and recorded. RESULTS: Male patients were prevalent with CHF whose LVEF<0.50. The occurrence of acute myocardial infarction in the 1st year [15.6% (34/218)] was higher than that of CHF with LVEF>or=0.5 [8.0% (16/199), P<0.01]. The occurrence of cerebral stroke in patients with atrial fibrillation [24.3% (27/111)] was higher than that of patients without atrial fibrillation [8.4% (9/107), P<0.05). The numbers of acute coronary syndrome and cardiac death were also increased. In the patients with CHF whose LVEF>or=0.50 the incidence atrial fibrillation occurring after readmission was significantly higher than that of patient with CHF whose LVEF<0.50 (51 vs. 30, P<0.05). Atrial fibrillation could be found in nearly 2/3 of patients. And the number of readmission (2.78+/-1.79 vs. 2.00+/-1.35, P<0.01) was increased, while the interval between discharge and readmission [(117+/-107) days vs. (154+/-130) days, P<0.05] was shorter. CONCLUSION: Atrial fibrillation occurs more likely in patients with CHF whose LVEF>or=0.50, leading to a shorter interval of readmission. Therefore the importance of treatment of atrial fibrillation should be emphasized.