Improved activity of Ni-Mo/SiO_(2) bimetallic catalyst synthesized via sol-gel method for methylcyclohexane cracking

To improve the cracking behavior of hydrocarbon,Ni-Mo/SiO_(2) bimetallic catalysts were synthesized by different preparation methods(sol-gel,co-impregnation and single-impregnation) and added the additives(citric acid,polyethylene glycol and cetyltrimethylammonium bromide) based on the most suitable method above.The cracking reaction of methylcyclohexane under supercritical conditions was performed as the probe reaction to estimate the catalytic performance,and the properties of Ni-Mo/SiO_(2) catalyst were characterized by N_(2) absorption-desorption,XRD,XPS,H_(2)-TPR,NH_(3)-TPD,in-situ IR of NH_(3) desorption,HRTEM and STEM-mapping so as to study the structure-activity relationship.The catalyst synthesized via sol-gel method showed the best conversion and heat sink,being 81.8% and 3.81 MJ/kg,which was closely related to strong mutual effect between active components and SiO_(2) as well as strong acid sites.Besides,the introduction of additives by sol-gel method has an affirmative influence on properties of Ni-Mo/SiO_(2) catalysts,being that the acidity(more L and B acid sites) was modulated and organic groups interact with metal to suppress the aggregation of metal species(Ni and Mo),thereby enhancing the catalytic activity.At 750℃,the conversion(89.3%) as well as heat sink(3.99 MJ/kg) of MCH cracking obtained an optimum over Ni-Mo/SiO_(2) catalyst with addition of citric acid.

Constipation-predominant irritable bowel syndrome: A review of current and emerging drug therapies

Irritable bowel syndrome(IBS) is a highly prevalent medical condition that adversely affects patient quality of life and constitutes a significant economic burden on healthcare resources. A large proportion of patients suffer from the constipation subtype of IBS(IBS-C), most commonly afflicting older individuals and those with a lower socioeconomic status. Conventional pharmacologic and nonpharmacologic treatment options have limited efficacies and/or significant adverse events, which lead to increased long-term health care expenditures. Failure to effectively treat IBS-C patients over the past decades has largely been due to a poor understanding of disease pathophysiology, lack of a global view of the patient, and an inappropriate selection of patients and treatment endpoints in clinical trials. In recent years, however, more effective and safer drugs have been developed for the treatment of IBS-C. The advancement in the area of pharmacologic treatment is based on new knowledge of the pathophysiologic basis of IBS-C and the development of drugs with increased selectivity within pharmacologic classes with recognized efficacies. This narrative review covers the spectrum of available drugs and their mechanisms of action, as well as the efficacy and safety profiles of each as determined in relevant clinical trials that have investigated treatment options for IBS-C and chronic constipation. A brief summary of laxative-based treatment options is presented, followed by up-to-date assessments for three classes of drugs: prokinetics, prosecretory agents, and bile acid modulators.

Defective NH_(2)-UiO-66(Zr) effectively converting CO_(2) into cyclic carbonate under ambient pressure,solvent-free and co-catalyst-free conditions

In this study,a series of metal-organic frameworks(MOFs)NH_(2)-UiO-66-x HAc catalysts were synthesized by solvothermal method using acetic acid(HAc)as a modulator,and were applied to the cycloaddition of CO_(2)and epichlorohydrin(EPIC)under ambient pressure.Influences of the modulation by HAc on morphologies and structures of the MOFs are demonstrated via PXRD,FESEM,FTIR,N_(2)adsorption-desorption,XPS and ^(1)H NMR characterizations.The results show that the MOFs containing mesoporous pores can be prepared by adjusting the concentration of HAc.By optimizing the amount of HAc added,the specific surface area of NH_(2)-UiO-66-8 HAc is as high as 879.17 m^(2)·g^(-1),which is 28.3%higher than that of the original MOFs.And the evaluation of catalytic performance showed that HAc modulation enhanced the activity of NH_(2)-UiO-66-x HAc under mild conditions.The exposure of Lewis acid sites,increased specific surface area and porosity via the modulation of HAc defective ligand can be supposed the key factors to determine the enhanced catalytic activities.In addition,considering the influence of gas concentration on the reaction,the concept of TOP(Turnover of Pressure,defined as the mass of conversions of a unit mass catalyst under unit pressure and unit time)was first proposed in this article.

Valproic acid as a micro RNA modulator to promote neurite outgrowth

Valproic acid （VPA） has been a first-choice drug for clinical treatment of epilepsy and manic disorder. For decades, its phar- macological action was believed to act on inhibition of gam- ma-aminobutyric acid （GABA） transaminase, in turn, increas- ing GABA in inhibitory synapses. However, in recent years, VPA has been investigated on other therapeutic actions. Those investigations demonstrate that VPA shows neuroprotective ef- fects by promoting neurogenesis, neuronal differentiation, and neuroregeneration （Foti et al., 2013）.

Solar-assisted photocatalytic water splitting using defective UiO-66 solids from modulated synthesis

Metal-organic frameworks(MOFs)are attracting increasing interests as photocatalysts for solar-driven hydrogen production from water.This paper reports on a comparative study of using either acetic acid(AA)or trifluoroacetic acid(TFA)as the representative UiO-66 organic modulators for synthesizing visible light responsive UiO-66(Zr)-X(X:NH_(2) or NO_(2))photocatalysts for water splitting.The results show that photocatalytic hydrogen generation from a water/methanol mixture can be improved by varying the nature and amount of the modulator employed to prepare the different UiO-66(Zr)-X(X:NH_(2) or NO_(2))solid derivatives.UiO-66(Zr)-NH_(2) was the most active photocatalyst,followed by UiO-66(Zr)-NO_(2),both prepared with 12 equivalents of AA with respect to the organic ligand.This UiO-66(Zr)-NH_(2) solid was more active than the parent MOF in photocatalytic overall water splitting(OWS)(H_(2) and O_(2) production of 450 and 160μmol·g^(-1),respectively,in 5 h;apparent quantum yield(AQY)at 400 nm of 0.06%)in the absence of methanol and compares favourably with analogous reports.Information on the photocatalytic activity of the most active solids of both series was obtained by means of a series of techniques,including ultraviolet-visible(UV-vis)diffuse reflectance,X-ray photoelectron spectroscopy(XPS),laser flash photolysis(LFP),electron spin resonance(ESR),photoluminescence and photoelectrochemical measurements together with density functional theory(DFT)calculations.The results showed that organic acid modulators can be used to enhance the photocatalytic activity of missing linker UiO-66 defective materials in solar-powered water splitting.