Search

Transition metal dichalcogenides represent an exciting class of earth-abundant hydrogen-from-water electrocatalysts, although low efficiencies limit commercialization. Here, authors present a doping strategy to induce a phase transition in cobalt selenide and boost H2-evolution performance.

Digital fabrication often requires a mixed initial interaction among the fabrication tools and the information behind it that is hard to align with users owing to the nature of a coexisting environment. This type of real-time digital fabrication process needs a cluster of sensing agents that can sense the needs of users in the environment and respond to users in real time. We propose a behavior sensing mechanism during the fabricating process. Our goal of this study is to improve the accuracy between the virtual data and the physical environment and enhance the smoothness of behavior feedbacks. We defined our own gesture identification rule to help users manage their fabrication process more easily. Besides, we also extend the possibility and the flexibility of the sensing mechanism to assist in human-machine collaboration with this specific coexisting design environment. [ABSTRACT FROM AUTHOR]

Density functional theory calculation was performed to study the adsorption and reaction of CH2I2 on Ag(111). Thermodynamically favorable reactions of CH2I2 on Ag(111) are C[Single_Bond]I bond ruptures and CH2 coupling to form ethylene. The energy barriers for the C[Single_Bond]I bond ruptures of chemisorbed CH2I2 on Ag(111) are 0.43–0.48 eV, whereas the activation energy for the C[Single_Bond]H bond rupture of chemisorbed CH2 on Ag(111) is 1.76 eV. The coupling reaction barrier of neighboring chemisorbed CH2 to form C2H4 on Ag(111) was much less than those of the C[Single_Bond]I bond ruptures of CH2I2(a) and the migration of chemisorbed CH2 on Ag(111). The adsorption behaviors of different surface species on Ag(111) were well explained in terms of the charge density difference. [ABSTRACT FROM AUTHOR]

Multi-walled carbon nanotubes (MWCNT) supported Cu-Co composite oxides catalysts were prepared by an ultrasonication treatment-aided impregnation method. The structure prop- erties of the catalysts were characterized by XRD, TEM, H2-TPR, XPS and Raman spectra, indicating the strong interactions between Cu and Co mixed oxides as well as between metal oxides and MWCNT support. The catalytic performance of CO removal in a H2-rich stream was examined. In contrast to the single Cu and Co catalyst, the unique performance was ob- served for Cu-Co composite catalysts, which features an unusual reaction pathway through the combination of CO preferential oxidation and CO methanation especially at high reac- tion temperature. The optimal catalyst with Cu/Co ratio of 1/8 can achieve the complete CO conversion in a wider temperature range of 150-250 °C under the space velocity as high as 120 L/(h-g), which demonstrates a promising catalyst for the e ective CO removal in a H2-rich stream. [ABSTRACT FROM AUTHOR]

Bifunctional TiO2 photocatalysts co-doped with nitrogen and sulfur were prepared by the controlled thermal decomposition of ammonium titanyl sulfate precursor. They have both photocatalytic activity and Br∅nsted acidity, and thus are active in the photoreduction of Cr(VI) under solar light irradiation without the addition of acids. The activity is superior to that of Degussa P25 in the acidified suspension at the same pH adjusted by H2SO4. [ABSTRACT FROM AUTHOR]

Co3O4/SiO2 catalysts for CO oxidation were prepared by conventional incipient wetness impregnation followed by calcination at various temperatures. Their structures were characterized with X-ray diffraction (XRD), laser Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR) and X-ray absorption fine structure (XAFS) spectroscopy. Both XRD and Raman spectroscopy only detect the existence of Co3O4 crystallites in all catalysts. However, XPS results indicate that excess Co2+ ions are present on the surface of Co3O4 in Co3O4(200)/SiO2 as compared with bulk Co3O4. Meanwhile, TPR results suggest the presence of surface oxygen vacancies on Co3O4 in Co3O4(200)/SiO2, and XAFS results demonstrate that Co3O4 in Co3O4(200)/SiO2 contains excess Co2+ . Increasing calcination temperature results in oxidation of excess Co2+ and the decrease of the concentration of surface oxygen vacancies, consequently the for- mation of stoichiometric Co3O4 on supported catalysts. Among all Co3O4/SiO2 catalysts, Co3O4(200)/SiO2 exhibits the best catalytic performance towards CO oxidation, demonstrating that excess Co 2+ and surface oxygen vacancies can enhance the catalytic activity of Co3O4 towards CO oxidation. These results nicely demonstrate the effect of calcination temperature on the structure and catalytic performance towards CO oxidation of silica- supported Co3O4 catalysts and highlight the important role of surface oxygen vacancies on Co3O4. [ABSTRACT FROM AUTHOR]

Aim: To investigate factors causing diabetes recurrence after sleeve gastrectomy (SG) and duodenal-jejunal bypass (DJB)., Methods: SG and DJB were performed on rats with diabetes induced by high-fat diet (HFD) and streptozotocin (STZ). HFD was used to induce diabetes recurrence at 4 wk postoperatively. Body weight, oral glucose tolerance test, homeostatic model assessment of insulin resistance (HOMA-IR), insulin signaling [IR, insulin receptor substrate (IRS)1, IRS2, phosphatidylinositol 3-kinase and AKT in liver and skeletal muscle], oral glucose stimulated insulin secretion, beta-cell morphology (mass, apoptosis and insulin secretion), glucagon-like peptide (GLP)-1, PYY and ghrelin were compared among SG rats with common low-fat diet (SG-LFD), SG with HFD (SG-HFD), DJB rats with LFD (DJB-LFD), DJB with HFD (DJB-HFD) and sham-operation with LFD (Sham) at targeted postoperative times., Results: SG and DJB resulted in significant improvement in glucose tolerance, lower HOMA-IR, up-regulated hepatic and muscular insulin signaling, higher levels of oral glucose-stimulated insulin secretion, bigger beta-cell mass, higher immunofluorescence intensity of insulin, fewer transferase-mediated dUTP-biotin 3' nick end-labeling (TUNEL)-positive beta cells and higher postprandial GLP-1 and PYY levels than in the Sham group. The improvement in glucose tolerance was reversed at 12 wk postoperatively. Compared with the SG-LFD and DJB-LFD groups, the SG-HFD and DJB-HFD groups showed higher HOMA-IR, down-regulated hepatic and muscular insulin signaling, and more TUNEL-positive beta cells. No significant difference was detected between HFD and LFD groups for body weight, glucose-stimulated insulin secretion, beta-cell mass, immunofluorescence intensity of insulin, and postprandial GLP-1 and PYY levels. Fasting serum ghrelin decreased in SG groups, and there was no difference between HFD-SG and LFD-SG groups., Conclusion: HFD reverses the improvement in glucose homeostasis after SG and DJB. Diabetes recurrence may correlate with re-impaired insulin sensitivity, but not with alterations of beta-cell function and body weight., Competing Interests: Conflict-of-interest statement: All authors have no conflict of interest related to the manuscript.