The selection of metal–organic frameworks (MOFs) for gas adsorption and separation has become a significant challenge over the past decade because of the large number of new structures reported every ...year. We applied a multiscale computational approach to screen existing MOFs for CO2/N2 separation. Pore characteristics of 1163 MOFs were analyzed by the method developed by Haldoupis, Nair, and Sholl (Haldoupis, E.; Nair, S.; Sholl, D. S. J. Am. Chem. Soc. 2010, 132, 7528) using a simple steric model. On the basis of the pore size analysis, 359 MOFs were examined by classical molecular simulations. Adsorption and diffusion properties were computed using grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations, respectively. These molecular simulations were used to assess which materials hold the greatest promise as membrane materials for CO2/N2 separations. Finally, density functional theory (DFT) calculations were performed to provide preliminary information on the dynamic framework motion of selected MOFs.
There have been several reports on improvements of the performance of all solid-state battery using lithium metal oxide coatings on the cathode active material. However, the mechanism of the ...performance improvement remains unclear. To better understand the effect of the surface coating, we studied the impact of diamond-like carbon (DLC) coating on LiNi0.8Co0.15Al0.05O2 (NCA) by chemical vapor deposition (CVD). The DLC coated NCA showed good cycle ability and rate performance. This result is further supported by reduction of the interfacial resistance of the cathode and electrolyte observed in impedance spectroscopy. The DLC layer was analyzed by transmission electron microscopy electron energy loss spectroscopy (TEM-EELS). After 100 cycles the sample was analyzed by X-ray photo spectroscopy (XPS), and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). These analyses showed that the thickness of the coating layer was around 4 nm on average, acting to hinder the side reactions between the cathode particle and the solid electrolyte. The results of this study will provide useful insights for understanding the nature of the buffer layer for the cathode materials.
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•DLC coating was applied on LiNi0.8Co0.15Al0.05O2 for the solid-state battery.•DLC layer improved the cycle performance of the cell.•Oxidation of the electrolyte was observed at cathode using TOF-SIMS.•Cycle performance was related to the formation of SOx and POx.
Lithium-sulfur (Li-S) batteries are promising candidates for next generation electrical energy storage devices due to their high specific energy. Despite intense research, there are still a number of ...technical challenges in developing a high performance Li-S battery. To elucidate the issues, an all solid-state Li-S battery was fabricated using Li3PS4 solid electrolyte. Most of the theoretical capacity of sulfur, 1600 mAhg−1 was attained in the initial discharge-charge cycles with a high coulombic efficiency approaching 99%. To verify the benefit of the solid state electrolyte, galvanostatic stripping-deposition tests were also carried out on a symmetrical Li/Li cell and compared with those of a liquid electrolyte (1 M- lithium bis(trifluoromethane sulfonyl) imide (LiTFSI) in a mixture of 1,3-dioxolane (DOL)-diethoxyethane (DEE)). The kinetics and thermodynamics of the solid-state cell are discussed from the viewpoint of the charge transfer processes. This study demonstrates both the merits and drawbacks of using the solid sulfide electrolyte in a Li-S battery and facilitates the further improvement of this important high energy storage device.
Objective In 2001, a landmark meta-analysis of bilateral internal thoracic artery (BITA) versus single internal thoracic artery (SITA) coronary artery bypass grafting for long-term survival included ...7 observational studies (only 3 of which reported adjusted hazard ratios HRs) enrolling approximately 16,000 patients. Updating the previous meta-analysis to determine whether BITA grafting reduces long-term mortality relative to SITA grafting, we exclusively abstracte, then combined in a meta-analysis, adjusted (not unadjusted) HRs from observational studies. Methods MEDLINE and EMBASE were searched until September 2013. Eligible studies were observational studies of BITA versus SITA grafting and reporting an adjusted HR for long-term (≥4 years) mortality as an outcome. Meta-regression analyses were performed to determine whether the effects of BITA grafting were modulated by the prespecified factors. Results Twenty observational studies enrolling 70,897 patients were identified and included. A pooled analysis suggested a significant reduction in long-term mortality with BITA relative to SITA grafting (HR, 0.80; 95% confidence interval, 0.77 to 0.84). When data from 6 pedicled and 6 skeletonized internal thoracic artery studies were separately pooled, BITA grafting was associated with a statistically significant 26% and 16% reduction in mortality relative to SITA grafting, respectively ( P for subgroup differences = .04). A meta-regression coefficient was significantly negative for the proportion of men (−0.00960; −0.01806 to −0.00114). Conclusions Based on an updated meta-analysis of exclusive adjusted HRs from 20 observational studies enrolling more than 70,000 patients, BITA grafting seems to significantly reduce long-term mortality. As the proportion of men increases, BITA grafting is more beneficial in reducing mortality.
Computational material discovery is under intense study owing to its ability to explore the vast space of chemical systems. Neural network potentials (NNPs) have been shown to be particularly ...effective in conducting atomistic simulations for such purposes. However, existing NNPs are generally designed for narrow target materials, making them unsuitable for broader applications in material discovery. Here we report a development of universal NNP called PreFerred Potential (PFP), which is able to handle any combination of 45 elements. Particular emphasis is placed on the datasets, which include a diverse set of virtual structures used to attain the universality. We demonstrated the applicability of PFP in selected domains: lithium diffusion in LiFeSO
F, molecular adsorption in metal-organic frameworks, an order-disorder transition of Cu-Au alloys, and material discovery for a Fischer-Tropsch catalyst. They showcase the power of PFP, and this technology provides a highly useful tool for material discovery.
The aim of this study was to examine the association of insulin resistance (evaluated by the short insulin tolerance test SITT) with parameters related to obesity and insulin resistance. We ...prospectively recruited controls and patients with type 2 diabetes mellitus (T2DM), subjected them to the SITT, and calculated the K indices of the intravenous insulin tolerance test (K.sub.ITT (iv)) and the subcutaneous insulin tolerance test (K.sub.ITT (sc)). We compared K.sub.ITT (iv) results between the volunteers and patients and examined its correlation with K.sub.ITT (sc). We also examined the association of K.sub.ITT (iv) with obesity, insulin resistance-related parameters, and the insulin dose required for glycemic control. A total of 24 participants (seven controls and 17 patients with T2DM) were studied. The mean K.sub.ITT (iv) was significantly lower in patients with T2DM than in the controls (2.5%±2.1% vs. 4.5%±1.8%). In all participants, K.sub.ITT (iv) was significantly correlated with the homeostasis model assessment for insulin resistance (HOMA-IR) values (r = -0.601, p<0.05) but not with K.sub.ITT (sc) (p = 0.62). K.sub.ITT (iv) was correlated positively with the serum adiponectin concentration, but negatively with the visceral fat area and serum concentrations of tumor necrosis factor-alpha and branched-chain amino acids. In patients with T2DM, K.sub.ITT (iv) and HOMA-IR values were significantly correlated with the total insulin dose required for glycemic control. Insulin resistance evaluated using K.sub.ITT (iv) was correlated with the HOMA-IR values, but not with the resistance evaluated using K.sub.ITT (sc). The degree of insulin resistance was associated with biomarkers, such as adiponectin, tumor necrosis factor-alpha, branched-chain amino acids, the visceral fat area, and the dose of insulin required for glycemic control.
Hepatic insulin signalling involves insulin receptor substrates (Irs) 1/2, and is normally associated with the inhibition of gluconeogenesis and activation of lipogenesis. In diabetes and obesity, ...insulin no longer suppresses hepatic gluconeogenesis, while continuing to activate lipogenesis, a state referred to as 'selective insulin resistance'. Here, we show that 'selective insulin resistance' is caused by the differential expression of Irs1 and Irs2 in different zones of the liver. We demonstrate that hepatic Irs2-knockout mice develop 'selective insulin resistance', whereas mice lacking in Irs1, or both Irs1 and Irs2, develop 'total insulin resistance'. In obese diabetic mice, Irs1/2-mediated insulin signalling is impaired in the periportal zone, which is the primary site of gluconeogenesis, but enhanced in the perivenous zone, which is the primary site of lipogenesis. While hyperinsulinaemia reduces Irs2 expression in both the periportal and perivenous zones, Irs1 expression, which is predominantly in the perivenous zone, remains mostly unaffected. These data suggest that 'selective insulin resistance' is induced by the differential distribution, and alterations of hepatic Irs1 and Irs2 expression.
The accuracy of echocardiographic parameters of right ventricular (RV) function has not been sufficiently validated in patients with pulmonary hypertension (PH). The aim of this study was to evaluate ...whether echocardiographic measurements reliably reflect RV systolic function in PH using cardiac magnetic resonance imaging (CMRI)-derived RV ejection fraction (RVEF) as a gold standard.
A total of 37 consecutive patients with PH, 20 with pulmonary arterial hypertension, 12 with chronic thromboembolic PH, and five others, were prospectively studied. All patients underwent echocardiography, CMRI, and right-heart catheterization within a 1-week interval. Associations between five echocardiography-derived parameters of RV systolic function and CMRI-derived RVEF were evaluated.
All five echocardiography-derived parameters were significantly correlated with CMRI-derived RVEF (percentage RV fractional shortening: r = 0.48, P = .0011; percentage RV area change: r = 0.40, P = .0083; tricuspid annular plane systolic excursion TAPSE: r = 0.86, P < .0001; RV myocardial performance index: r = -0.59, P < .0001; and systolic lateral tricuspid annular motion velocity: r = 0.63, P < .0001). Compared with the other indices, TAPSE exhibited the highest correlation coefficient. Of the five echocardiographic measurements, only TAPSE significantly predicted CMRI-derived RVEF in multiple regression analysis (P < .0001). Intraobserver and interobserver reproducibility was favorable for all five indices and was particularly high for TAPSE and systolic lateral tricuspid annular motion velocity.
Echocardiographic measurements are promising noninvasive indices of RV systolic function in patients with PH. In particular, TAPSE is superior to other indices in accuracy.
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