822 research outputs found

    Waste Edible Oil Fluid Catalytic Cracking in a Downer Reactor

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    The waste edible oil fluid catalytic cracking process (FCC), an environment friendly process to produce clean fuel (such as gasoline, diesel) and high-value chemical materials (such as propylene), was studied in an small hot model of downer reactor under the temperature 500 ℃, the pressure 1.1×105Pa , the resident time 1 second, the ratio of catalyst to oil 12 , and MA-83 as the catalyst. Compared with other processes, the waste edible oil FCC process can realize the waster utilizing and adjust the product distribution according to the market demand, while with a convenient pretreatment to the raw materials. The experimental results showed that the waste edible oil and cottonseed oil fluid catalytic cracking process have the similar product distribution: liquefied petroleum gas (LPG) 10.3wt%, gasoline 36.4wt%, diesel oil wt23%. And the desired product the gasoline and diesel with trace content of sulfur, nitrogen and heavy metals, have the similar molecular weight and chemical structure to the gasoline and diesel from petroleum-based fuel. Therefore, the waste edible oil fluid catalytic cracking is a promising process, with both economic and environmental benefit

    Optimising terpene synthesis with flow biocatalysis

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    Sesquiterpenes are an important family of natural products, many of which exhibit important pharmaceutical and agricultural properties. They are biosynthesised from farnesyl diphosphate in sesquiterpene synthase catalysed reactions. Here, we report the development of a highly efficient segmented flow system for the enzyme‐catalysed continuous flow production of sesquiterpenes. Design of experiment (DoE) methods were used to optimise the performance of the flow biocatalysis, and quantitative yields were achieved by using an operationally simple but highly effective segmented flow system

    Analysis of significant factors on cable failure using the Cox proportional hazard model

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    This paper proposes the use of the Cox proportional hazard model (Cox PHM), a statistical model, for the analysis of early-failure data associated with power cables. The Cox PHM analyses simultaneously a set of covariates and identifies those which have significant effects on the cable failures. In order to demonstrate the appropriateness of the model, relevant historical failure data related to medium voltage (MV, rated at 10 kV) distribution cables and High Voltage (HV, 110 kV and 220 kV) transmission cables have been collected from a regional electricity company in China. Results prove that the model is more robust than the Weibull distribution, in that failure data does not have to be homogeneous. Results also demonstrate that the method can single out a case of poor manufacturing quality with a particular cable joint provider by using a statistical hypothesis test. The proposed approach can potentially help to resolve any legal dispute that may arise between a manufacturer and a network operator, in addition to providing guidance for improving future practice in cable procurement, design, installations and maintenance

    Achieving SDG related sexual and reproductive health targets in China: what are appropriate indicators and how we interpret them?

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    Background: Sexual and Reproductive Health (SRH) targets have been included as part of the United Nations Sustainable Development Goals and thus indictors are important to monitor the progress towards these targets. SRH indicators are recommended for setting norms and measuring progress at global level. However, given the diverse political, socioeconomic and cultural contexts in different countries, and lack of global agreement on broad indicators, it is important to select appropriate indicators for specific countries. Based on internationally recommended indicators and data availability in China, this paper selected four indictors to reflect SRH in China and interpreted these indictors by analyzing the underlying factors. Methods: we employed secondary data analysis and key informant interview. The major secondary data were obtained from the China Health Statistical Year Book (2005-2017), China Statistical Year Book (2005-2017), and the sub-national estimates of the Global Burden Diseases Study 2016. We also interviewed 36 key informants at national and sub-national levels. Results: the four selected SRH indicators are contraceptive prevalence rate (CPR), adolescent birth rate, abortion rate, and availability of school sex education. CPR of married women has remained above 75% over the last three decades, indicating a high level of access to family planning (FP) services; however, unmarried but sexually active women have significant unmet needs for FP services. Although adolescent birth rates in China remain low, the abortion rate, abortion numbers, and the ratio of abortions to births increased from 2014-2016 while FP policy was relaxed in China. This suggests that abortion among unmarried women is a significant contributor to the overall figures. Qualitative analysis of the availability of school sex education reveals a situation of policy absence and the conservative attitude of key stakeholders. Conclusion: Since SRH challenges vary significantly between socio-economic, political and cultural contexts, indicators for measuring progress towards SRH targets of SDGs should be selected based on country context. The CPR and abortion rate are currently available and important indicators to monitor the most basic part of SRH in China, but require modification to ensure they can reflect universal access to quality reproductive healthcare by all reproductive age women, regardless their marriage status. Indicators on sex education need to be carefully developed to fit the context in China

    Development of a redox-free mitsunobu reaction exploiting phosphine oxides as precursors to dioxyphosphoranes

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    The development of the first redox-free protocol for the Mitsunobu reaction is described. This has been achieved by exploiting triphenylphosphine oxide – the unwanted by-product in the conventional Mitsunobu reaction – as the precursor to the active P(V) coupling reagent. Multinuclear NMR studies are consistent with hydroxyl activation via an alkoxyphosphonium salt

    Baicalein and U0126 suppress bladder cancer proliferation via MAPK signaling pathway

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    Purpose: To investigate baicalein and 1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio] butadiene (U0126)effects on human bladder cell line T24 proliferation and related mechanisms.Methods: Twenty micromoles of baicalein or 10 μM U0126 were incubated with T24 cells. Cell viability was tested by CCK8 assay. Cell cycle was evaluated by flow cytometry while cell apoptosis was detected by Annexin V/PI and TUNEL assay. MAPK signaling pathway was evaluated by real time polymerase chain reaction (RT-PCR) and western blot.Results: Baicalein and U0126 suppressed bladder cancer cell T24 proliferation by blocking cell cycle in G0~G1 phase. TUNEL and Annexin V/PI detection showed both baicalein and U0126 induced T24 cell apoptosis. Baicalein and U0126 significantly down-regulated MAPK signaling pathway related molecule activity in both mRNA and protein levels (p < 0.05).Conclusion: Baicalein and U0126 restrain bladder cancer cell proliferation and promote cell apoptosis by affecting MAPK signaling pathway. Thus, they have  potentials for use in the treatment of bladder cancer.Keywords: Bladder cancer, Baicalein, 1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio] butadiene, MAPK signal pathway, Apoptosi

    Concise synthesis of artemisinin from a farnesyl diphosphate analogue

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    Artemisinin is one of the most potent anti-malaria drugs and many often-lengthy routes have been developed for its synthesis. Amorphadiene synthase, a key enzyme in the biosynthetic pathway of artemisinin, is able to convert an oxygenated farnesyl diphosphate analogue directly to dihydroartemisinic aldehyde, which can be converted to artemisinin in only four chemical steps, resulting in an efficient synthetic route to the anti-malaria drug
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