Atomically Dispersed Pd on Nanodiamond/Graphene Hybrid for Selective Hydrogenation of Acetylene

An atomically dispersed palladium (Pd) catalyst supported onto a defective nanodiamond-graphene (ND@G) is reported here for selective hydrogenation of acetylene in the presence of abundant ethylene. The catalyst exhibits remarkable performance for the selective conversion of acetylene to ethylene: high conversion (100%), ethylene selectivity (90%), and good stability (i.e., steady for at least 30 hours). The unique struc-ture of the catalyst (i.e., atomically dispersion of Pd atoms on graphene through Pd-C bond anchoring) ensure the facile desorption of ethylene against the over-hydrogenation of ethylene to undesired ethane, which is the key for the outstanding selectivity of the catalyst

Anchoring Cu 1 species over nanodiamond-graphene for semi-hydrogenation of acetylene

The design of cheap, non-toxic, and earth-abundant transition metal catalysts for selective hydrogenation of alkynes remains a challenge in both industry and academia. Here, we report a new atomically dispersed copper (Cu) catalyst supported on a defective nanodiamondgraphene (ND@G), which exhibits excellent catalytic performance for the selective conversion of acetylene to ethylene, i.e., with high conversion (95%), high selectivity (98%), and good stability (for more than 60 h). The unique structural feature of the Cu atoms anchored over graphene through Cu-C bonds ensures the effective activation of acetylene and easy desorption of ethylene, which is the key for the outstanding activity and selectivity of the catalyst

Tin Assisted Fully Exposed Platinum Clusters Stabilized on Defect-Rich Graphene for Dehydrogenation Reaction

Tin assisted fully exposed Pt clusters are fabricated on the core-shell nanodiamond@graphene (ND@G) hybrid support (a-PtSn/ND@G). The obtained atomically dispersed Pt clusters, with an average Pt atom number of 3, were anchored over the ND@Gsupport by the assistance of Sn atoms as a partition agent and through the Pt-C bond between Pt clusters and defect-rich graphene nanoshell. The atomically dispersed Pt clusters guaranteed a full metal availability to the reactants, a high thermal stability, and an optimized adsorption/desorption behavior. It inhibits the side reactions and enhances catalytic performance in direct dehydrogenation of n-butane at a low temperature of 450 °C, leading to \u3e98% selectivity toward olefin products, and the turnover frequency (TOF) of a-PtSn/ND@G is approximately 3.9 times higher than that of the traditional Pt3Sn alloy catalyst supported on Al2O3 (Pt3Sn/Al2O3)

Effect of Ginkgo Biloba on Visual Field and Contrast Sensitivity in Chinese Patients With Normal Tension Glaucoma: A Randomized, Crossover Clinical Trial

Citation: Guo X, Kong X, Huang R, et al. Effect of Ginkgo biloba on visual field and contrast sensitivity in Chinese patients with normal tension glaucoma: a randomized, crossover clinical trial. Invest Ophthalmol Vis Sci. 2014;55:110-116. DOI: 10.1167/iovs.13-13168 PURPOSE. We evaluated the effect of ginkgo biloba extract on visual field defect and contrast sensitivity in a Chinese cohort with normal tension glaucoma. METHODS. In this prospective, randomized, placebo-controlled crossover study, patients newly diagnosed with normal tension glaucoma, either in a tertiary glaucoma clinic (n ¼ 5) or in a cohort undergoing routine general physical examinations in a primary care clinic (n ¼ 30), underwent two 4-week phases of treatment, separated by a washout period of 8 weeks. Randomization determined whether ginkgo biloba extract (40 mg, 3 times per day) or placebo (identical-appearing tablets) was received first. Primary outcomes were change in contrast sensitivity and mean deviation on 24-2 SITA standard visual field testing, while secondary outcomes included IOP and self-reported adverse events. RESULTS. A total of 35 patients with mean age 63.7 (6.5) years were randomized to the ginkgo biloba extract-placebo (n ¼ 18) or the placebo-ginkgo biloba extract (n ¼ 17) sequence. A total of 28 patients (80.0%, 14 in each group) who completed testing did not differ at baseline in age, sex, visual field mean deviation, contrast sensitivity, IOP, or blood pressure. Changes in visual field and contrast sensitivity did not differ by treatment received or sequence (P > 0.2 for all). Power to have detected a difference in mean defect as large as previously reported was 80%. CONCLUSIONS. In contrast to some previous reports, ginkgo biloba extract treatment had no effect on mean defect or contrast sensitivity in this group of normal tension glaucoma patients. (http://www.chictr.org number, ChiCTR-TRC-08000724

Proteomic Studies on the Mechanism of Myostatin Regulating Cattle Skeletal Muscle Development

Myostatin (MSTN) is an important negative regulator of muscle growth and development. In this study, we performed comparatively the proteomics analyses of gluteus tissues from MSTN+/− Mongolian cattle (MG.MSTN+/−) and wild type Mongolian cattle (MG.WT) using a shotgun-based tandem mass tag (TMT) 6-plex labeling method to investigate the regulation mechanism of MSTN on the growth and development of bovine skeletal muscle. A total of 1,950 proteins were identified in MG.MSTN+/− and MG.WT. Compared with MG.WT cattle, a total of 320 differentially expressed proteins were identified in MG.MSTN cattle, including 245 up-regulated differentially expressed proteins and 75 down-regulated differentially expressed proteins. Bioinformatics analysis showed that knockdown of the MSTN gene increased the expression of extracellular matrix and ribosome-related proteins, induced activation of focal adhesion, PI3K-AKT, and Ribosomal pathways. The results of proteomic analysis were verified by muscle tissue Western blot test and in vitro MSTN gene knockdown test, and it was found that knockdown MSTN gene expression could promote the proliferation and myogenic differentiation of bovine skeletal muscle satellite cells (BSMSCs). At the same time, Co-Immunoprecipitation (CO-IP) assay showed that MSTN gene interacted with extracellular matrix related protein type I collagen α 1 (COL1A1), and knocking down the expression of COL1A1 could inhibit the activity of adhesion, PI3K-AKT and ribosome pathway, thus inhibit BSMSCs proliferation. These results suggest that the MSTN gene regulates focal adhesion, PI3K-AKT, and Ribosomal pathway through the COL1A1 gene. In general, this study provides new insights into the regulatory mechanism of MSTN involved in muscle growth and development

Radiation hardened ICs

This final year project develops a new Radiation-Hardened-By-Design approach to detect Single Event Latchup (SEL) by monitoring the transient current slope, which is proven with reliable immunity to SEL. The object is to reduce the cost of Radiation-Hardened-By-Process technique by benefiting from the low cost mass produced integrated circuits. A comprehensive literature review is conducted and it is found that the SEL current ramps up sharply with an increasing slope. This distinguishing characteristic is verified through both theoretical analysis and reasonable model simulations. The desired SEL detection and protection circuit is designed based on the verified current characteristic. Firstly, the SEL triggering current is converted into a corresponding voltage variation through the Current-to-Voltage converter stage. Secondly, the voltage is sampled and fed into the comparator stage. Thirdly, a high speed comparator stage with proper hysteresis is designed to detect the SEL occurrence and generate corresponding output logic. Lastly, the output logic modulation stage is designed to filter out noises and reshape the output logic. Overall, this project proposes a useful method of the SEL detection and protection design.Bachelor of Engineerin

Identity of Fluoride and Phosphate-Binding Sites at FeOOH Surfaces

Iron oxyhydroxides are of widespread occurrence in nature and play essential roles in both environmental as well as industrial processes. Due to their high reactivity, these minerals can act as sinks and/or transformation centers for a variety of inorganic and organic ions. These reactions are often mediated by various surface hydroxyl groups that are in turn singly-, doubly- or triply-coordinated with respect to underlying Fe atoms. In an effort to follow the reactivity of these different groups, attenuated total reflectance (ATR) - Fourier transform infrared (FTIR) spectroscopy was used to monitor adsorption reactions of on iron oxyhydroxide minerals. This work was specifically focused on synthetic submicron-sized lepidocrocite and goethite particles reacted to aqueous solutions of sodium fluoride and sodium phosphate. Langmuir-Freundlich adsorption isotherms were calibrated on adsorption data at various pH values to provide independent clues to the maximum sorption density achieved by these ions. When compared to theoretical site densities, these values suggested that although singly-coordinated groups are by far the more reactive groups on all surfaces, doubly-coordinated groups could be substituted by fluoride ions. FTIR measurements of dry mineral samples equilibrated with fluoride and phosphate confirmed these findings and also showed that triply-coordinated groups cannot be exchanged. Key words : goethite, lepidocrocite, FTIR, surface, adsorption, isotherm, modelin

A fast-transient DC-DC buck converter

With the rapid development of system-on-chip integration and continuously scaling-down power supply, nowadays portable battery-powered devices have higher and sharper energy requirements. Switching converters are widely used as voltage regulators in those devices because of its high power-conversion efficiency. Due to the high-speed application and different modes operation requirements, the embedded microprocessors or digital systems operate at a higher frequency and the system need to switch between different modes more frequently. The frequently changing load induces significant undershoot/overshoot variation, which will deteriorate the overall system performance and stability. In this prospective, the fast-transient response becomes one of the key requirements for DC-DC converters in nowadays high-performance applications. Investigation of fast-transient techniques has been conducted to improve the transient response of DC-DC buck converters. A new pumping control scheme called Power-Driving-Tracked-Duration (PDTD) control is proposed to enhance the transient performance in the voltage-mode hysteretic DC-DC converters. It operates only when a large load current change is detected. Comparing with conventional counterparts, it simultaneously accelerates the transient response, reduces the undershoot/overshoot voltage and the effect of multiple undershoots/overshoots during the load current transitions. A theoretical analysis is also conducted to validate the circuit technique. The measured output voltage ripple is about 60mVpp. The obtained undershoot/overshoot settling time is 369ns/335ns in response to a 60-to-300mA/300-to-60mA load current step. The peak efficiency is about 93%. The prototype is fabricated using TSMC 40nm CMOS process as a proof-of-concept.Master of Engineerin

Construction of Insurance Consumers' Purchasing Behavior Model Based on Big Data Analysis

The social capital theory is selected as the theoretical basis, and the decision-making of household commercial insurance purchase is taken as the research object. By using the frontier theory of big data, an improved K-means clustering algorithm is proposed to segment customers first, then the results of the segmentation are predicted and analyzed. Finally, an insurance consumer purchase behavior model is proposed, and an empirical test is carried out according to the proposed model. Social capital and its three dimensions can promote the possibility in family commercial insurance, thus ultimately promoting residents' families to make purchase decisions on commercial insurance