Hydrogenation of Dimethyl Oxalate to Ethylene Glycol Over Silica Supported Copper Catalysts

Ethylene glycol is a bulk chemical and hydrogenation of dimethyl oxalate (DMO) on Cu/SiO2 catalysts is the final reaction step in a growing industrial syngas to ethylene glycol (StEG) process. Efforts to improve the performance of the catalysts are still ongoing and the detailed catalytic mechanism remains controversial. In the present work, a series of 10 wt% Cu/SiO2 is prepared.by urea hydrolysis method and indium species is introduced by incipient wetness impregnation. Reaction studies show that 0.25 wt%-0.5 wt% of indium species can dramatically enhance the performance of 10 wt% Cu/SiO2 catalyst. Various characterizations reveal that indium species are partially reduced and have negligible effect on the content of Cu+ species on the surface. Rather, the promotional effect likely originates from interactions between reduced indium species and Cu0 species though enhanced ability of the latter to activate H2. Support materials and the synthesis parameters (AE temperature and copper loading) are also optimized to prepare Cu/SiO2 catalysts as Cu+ species for the activation of C=O group in the reaction comes from Cu species strongly interacted with SiO2 during catalyst synthesis. KIT-6 supported copper catalysts are prepared via ammonia evaporation (AE) method. The mesoporous, interconnected channels of KIT-6 facilitate the dispersion of copper species. Reaction studies indicate that loading amount of copper species significantly influence the hydrogenation performance. Both AE temperature and loading amount of copper species influence the intrinsic activity. The hydrogenation of DMO to EG is proposed to proceed via the synergy between Cu0 and Cu+ sites and catalysts with the highest surface Cu0 content exhibit the highest intrinsic activity in the investigated range. The adsorption DMO over Cu2+/SiO2 prepared by urea hydrolysis is studied via ATR-FTIR to know how C-O and/or C=O bond adsorb on the surface at room temperature. The results show that silica does not adsorb dimethyl oxalate and the primary intermediates over the surface of Cu2+-containing sample are identified as adsorption of two C=O groups via bidentate mode (1606 cm-1), acyl species (1357 cm-1, 1315 cm-1) and alkoxy C-O species (1045 cm-1)

Critical Roles of microRNA-141-3p and CHD8 in Hypoxia/Reoxygenation-Induced Cardiomyocyte Apoptosis

Background: Cardiovascular diseases are currently the leading cause of death in humans. The high mortality of cardiac diseases is associated with myocardial ischemia and reperfusion (I/R). Recent studies have reported that microRNAs (miRNAs) play important roles in cell apoptosis. However, it is not known yet whether miR-141-3p contributes to the regulation of cardiomyocyte apoptosis. It has been well established that in vitro hypoxia/reoxygenation (H/R) model can follow in vivo myocardial I/R injury. This study aimed to investigate the effects of miR-141-3p and CHD8 on cardiomyocyte apoptosis following H/R. Results: We found that H/R remarkably reduces the expression of miR-141-3p but enhances CHD8 expression both in mRNA and protein in H9c2 cardiomyocytes. We also found either overexpression of miR-141-3p by transfection of miR-141-3p mimics or inhibition of CHD8 by transfection of small interfering RNA (siRNA) significantly decrease cardiomyocyte apoptosis induced by H/R. Moreover, miR-141-3p interacts with CHD8. Furthermore, miR-141-3p and CHD8 reduce the expression of p21. Conclusion: MiR-141-3p and CHD8 play critical roles in cardiomyocyte apoptosis induced by H/R. These studies suggest that miR-141-3p and CHD8 mediated cardiomyocyte apoptosis may offer a novel therapeutic strategy against myocardial I/R injury-induced cardiovascular diseases

Goal-Directed Processing of Naturalistic Stimuli Modulates Large-Scale Functional Connectivity

Humans selectively process external information according to their internal goals. Previous studies have found that cortical activity and interactions between specific cortical areas such as frontal-parietal regions are modulated by behavioral goals. However, these results are largely based on simple stimuli and task rules in laboratory settings. Here, we investigated how top-down goals modulate whole-brain functional connectivity (FC) under naturalistic conditions. Analyses were conducted on a publicly available functional magnetic resonance imaging (fMRI) dataset (OpenfMRI database, accession number: ds000233) collected on twelve participants who made either behavioral or taxonomic judgments of behaving animals containing in naturalistic video clips. The task-evoked FC patterns of the participants were extracted using a novel inter-subject functional correlation (ISFC) method that increases the signal-to-noise ratio for detecting task-induced inter-regional correlation compared with standard FC analysis. Using multivariate pattern analysis (MVPA) methods, we successfully predicted the task goals of the participants with ISFC patterns but not with standard FC patterns, suggests that the ISFC method may be an efficient tool for exploring subtle network differences between brain states. We further examined the predictive power of several canonical brain networks and found that many within-network and across-network ISFC measures supported task goals classification. Our findings suggest that goal-directed processing of naturalistic stimuli systematically modulates large-scale brain networks but is not limited to the local neural activity or connectivity of specific regions

Analysis of tall fescue ESTs representing different abiotic stresses, tissue types and developmental stages

<p>Abstract</p> <p>Background</p> <p>Tall fescue (<it>Festuca arundinacea </it>Schreb) is a major cool season forage and turf grass species grown in the temperate regions of the world. In this paper we report the generation of a tall fescue expressed sequence tag (EST) database developed from nine cDNA libraries representing tissues from different plant organs, developmental stages, and abiotic stress factors. The results of inter-library and library-specific <it>in silico </it>expression analyses of these ESTs are also reported.</p> <p>Results</p> <p>A total of 41,516 ESTs were generated from nine cDNA libraries of tall fescue representing tissues from different plant organs, developmental stages, and abiotic stress conditions. The <it>Festuca </it>Gene Index (FaGI) has been established. To date, this represents the first publicly available tall fescue EST database. <it>In silico </it>gene expression studies using these ESTs were performed to understand stress responses in tall fescue. A large number of ESTs of known stress response gene were identified from stressed tissue libraries. These ESTs represent gene homologues of heat-shock and oxidative stress proteins, and various transcription factor protein families. Highly expressed ESTs representing genes of unknown functions were also identified in the stressed tissue libraries.</p> <p>Conclusion</p> <p>FaGI provides a useful resource for genomics studies of tall fescue and other closely related forage and turf grass species. Comparative genomic analyses between tall fescue and other grass species, including ryegrasses (<it>Lolium </it>sp.), meadow fescue (<it>F. pratensis</it>) and tetraploid fescue (<it>F. arundinacea var glaucescens</it>) will benefit from this database. These ESTs are an excellent resource for the development of simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) PCR-based molecular markers.</p

Neutron scattering studies of heterogeneous catalysis

Understanding the structural dynamics/evolution of catalysts and the related surface chemistry is essential for establishing structure–catalysis relationships, where spectroscopic and scattering tools play a crucial role. Among many such tools, neutron scattering, though less-known, has a unique power for investigating catalytic phenomena. Since neutrons interact with the nuclei of matter, the neutron–nucleon interaction provides unique information on light elements (mainly hydrogen), neighboring elements, and isotopes, which are complementary to X-ray and photon-based techniques. Neutron vibrational spectroscopy has been the most utilized neutron scattering approach for heterogeneous catalysis research by providing chemical information on surface/bulk species (mostly H-containing) and reaction chemistry. Neutron diffraction and quasielastic neutron scattering can also supply important information on catalyst structures and dynamics of surface species. Other neutron approaches, such as small angle neutron scattering and neutron imaging, have been much less used but still give distinctive catalytic information. This review provides a comprehensive overview of recent advances in neutron scattering investigations of heterogeneous catalysis, focusing on surface adsorbates, reaction mechanisms, and catalyst structural changes revealed by neutron spectroscopy, diffraction, quasielastic neutron scattering, and other neutron techniques. Perspectives are also provided on the challenges and future opportunities in neutron scattering studies of heterogeneous catalysis

MicroRNA let-7c Is Downregulated in Prostate Cancer and Suppresses Prostate Cancer Growth

Prostate cancer (PCa) is characterized by deregulated expression of several tumor suppressor or oncogenic miRNAs. The objective of this study was the identification and characterization of miR-let-7c as a potential tumor suppressor in PCa.Levels of expression of miR-let-7c were examined in human PCa cell lines and tissues using qRT-PCR and in situ hybridization. Let-7c was overexpressed or suppressed to assess the effects on the growth of human PCa cell lines. Lentiviral-mediated re-expression of let-7c was utilized to assess the effects on human PCa xenografts.We identified miR-let-7c as a potential tumor suppressor in PCa. Expression of let-7c is downregulated in castration-resistant prostate cancer (CRPC) cells. Overexpression of let-7c decreased while downregulation of let-7c increased cell proliferation, clonogenicity and anchorage-independent growth of PCa cells in vitro. Suppression of let-7c expression enhanced the ability of androgen-sensitive PCa cells to grow in androgen-deprived conditions in vitro. Reconstitution of Let-7c by lentiviral-mediated intratumoral delivery significantly reduced tumor burden in xenografts of human PCa cells. Furthermore, let-7c expression is downregulated in clinical PCa specimens compared to their matched benign tissues, while the expression of Lin28, a master regulator of let-7 miRNA processing, is upregulated in clinical PCa specimens.These results demonstrate that microRNA let-7c is downregulated in PCa and functions as a tumor suppressor, and is a potential therapeutic target for PCa

Methylmercury Exposure and Health Effects from Rice and Fish Consumption: A Review

Methylmercury (MeHg) is highly toxic, and its principal target tissue in humans is the nervous system, which has made MeHg intoxication a public health concern for many decades. The general population is primarily exposed to MeHg through consumption of contaminated fish and marine mammals, but recent studies have reported high levels of MeHg in rice and confirmed that in China the main human exposure to MeHg is related to frequent rice consumption in mercury (Hg) polluted areas. This article reviews the progress in the research on MeHg accumulation in rice, human exposure and health effects, and nutrient and co-contaminant interactions. Compared with fish, rice is of poor nutritional quality and lacks specific micronutrients identified as having health benefits (e.g., n-3 long chain polyunsaturated fatty acid, selenium, essential amino acids). The effects of these nutrients on the toxicity of MeHg should be better addressed in future epidemiologic and clinical studies. More emphasis should be given to assessing the health effects of low level MeHg exposure in the long term, with appropriate recommendations, as needed, to reduce MeHg exposure in the rice-eating population

Hydroformylation over polyoxometalates supported single-atom Rh catalysts

Atomic dispersion of Rh on phosphotungstic acid (PTA) salts was achieved by a self-assembled precipitation method using alkali metal ions as coprecipitation reagents. During styrene hydroformylation, the supported Rh single-atom catalyst (Rh1/M-PTA, M refers to an alkali metal ion) demonstrated an optimum turnover frequency (TOF) of 1076 h−1. With increasing ionic radius, the pore size of the catalysts increased in the following order: Rh1/K-PTA<Rh1/Rb-PTA<Rh1/Cs-PTA. The catalytic activity showed the same trend, suggesting a positive correlation between pore size and hydroformylation performance. Further experimental data suggested that temperature is an important factor affecting not only the activity but also the selectivity. This study enriches the understanding of the structure and catalytic properties of PTA-supported single-atom materials. The cation-controlled synthesis of catalysts may also be applied to prepare other single-atom catalysts with tunable pore size distributions