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Food Hygiene and Safety Practices amongst Food Vendors in the Western Area, Sierra Leone

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Food and Nutrition Sciences 2024年第6期15卷 421-431页

作者： Philip john Kanu Hamid Turay Milton Margai Technical University Freetown Sierra Leone Centre for Development and Food Safety (SL) Limited Freetown Sierra Leone Institute of Food Technology Nutrition and Consumer Studies Njala University Njala Sierra Leone

Food safety and hygiene practices require a multisectoral approach including food, water, sanitation, waste management, transport, education, trade, policies and programs that enable safe food preparation, storage and service. Unsafe food can cause illness keeping people from achieving their full potential and death. This was a descriptive study that uses a mixed method approach to derive insights into the characteristics of food vendors related to demography, knowledge, practices, infrastructure, compliance and recommendation for a policymaking framework. Using the Lemeshows’ sample size formula, 473 vendors from formal (restaurants) and informal (cookri-baffa/table top) sites were interviewed and observed. We found from discussions that respondents had a good understanding on how to keep food safe. However, observed practices were poor 93% handled food with their bare hands, 83% did not cover their hair, and 76% did not wear an apron whilst handling, preparing or serving food, 61% did not keep their finger nails clean or short and 57% did not wash their hand before preparing or serving food. Over half (51%) had access to a toilet but 32% reported their use required payment and emphasized their poor condition/inadequate management. Nearly half (47%) of the vending sites did not have a handwashing facility, with soap and water available. Only 7% reported having any authority oversight of food safety. Food safety and hygiene practices in most cookri shops and restaurants was ‘poor’ with very limited surveillance system in place by competent authorities for compliance of food operators. Hand washing, clean surroundings, and covered food were the most common and emphasized practices to mitigate the risks associated with unsafe food.

关键词： Food Safety and Hygiene Formal and Informal Food Vendors Western Area Sierra Leone

Results of the Second Life Metabolism Travel Awards 2024

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Life Metabolism 2024年第3期3卷 1-2页

作者： john R.Speakman Shenzhen Key Laboratory of Metabolic Health Center for Energy Metabolism and ReproductionShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518055China State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China Institute of Biological and Environmental Sciences University of AberdeenAberdeenAB242TZScotlandUnited Kingdom

This year is the second year of the Life Metabolism Travel Prize Awards for PhD students and *** three 700 US$awards are generously sponsored by Sable Systems-Promethion(China)who manufacture metabolic *** I announce the winners and their interesting projects,I will just reiterate how the judging of the awards *** first remove anything from the submission that would identify the sex,affiliation,or ethnicity of the applicant.

关键词： remove Travel Awards

Frameworked electrolytes:Ionic transport behavior and high mobility for solid state batteries

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InfoMat 2024年第2期6卷 76-89页

作者： Jianguo Sun Hao Yuan Jing Yang Tuo Wang Yulin Gao Qi Zhao Ximeng Liu Haimei Wang Yong-Wei Zhang john Wang Department of Materials Science and Engineering National University of SingaporeSingaporeSingapore Institute of High Performance Computing(IHPC) Agency for ScienceTechnology and Research(A*STAR)SingaporeSingapore ST Engineering Advanced Material Engineering Pte.Ltd. SingaporeSingapore National University of Singapore(Chongqing)Research Institute Chongqing Liang Jiang New AreaChongqingthe People's Republic of China Institute of Materials Research and Engineering(IMRE) Agency for ScienceTechnology and Research(A*STAR)SingaporeSingapore

All solid-state batteries(ASSBs)are the holy grails of rechargeable batteries,where extensive searches are ongoing in the pursuit of ideal solid-state ***,there is still a long way off to the satisfactorily high(enough)ionic conductivity,long-term stability and especially being able to form compatible interfaces with the solid ***,we have explored ionic transport behavior and high mobility in the sub-nano pore networks in the framework ***,the frameworked electrolyte behaves as a solid,and however in the(sub)-nano scales,the very limited number of solvent molecules in confinement makes them completely different from that in liquid *** from a liquid-electrolyte counterpart,the interactions between the mobile ions and surrounding molecules are subject to dramatic changes,leading to a high ionic conductivity at room temperature with a low activation ***+ions in the sub-nano cages of the network structure are highly mobile and diffuse rather independently,where the rate-limiting step of ions crossing cages is driven by the local concentration gradient and the electrostatic interactions between Li^(+)*** new class of frameworked electrolytes(FEs)with both high ionic conductivity and desirable interface with solid electrodes are demonstrated to work with Li-ion batteries,where the ASSB with LiFePO_(4)shows a highly stable electrochemical performance of over 450 cycles at 2℃ at room temperature,with an almost negligible capacity fade of 0.03‰ each *** addition,the FE shows outstanding flexibility and anti-flammability,which are among the key requirements of large-scale applications.

关键词： frameworked electrolyte macroscopically solid with 3D ionic channels in sub-nano-scales solid-state battery space confinement of Li ions

New dating indicates intermittent human occupation of the Nwya Devu Paleolithic site on the high-altitude central Tibetan Plateau during the past 45,000 years

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Science China Earth Sciences 2024年第2期67卷 531-551页

作者： Junyi GE Xiaoling ZHANG Shejiang WANG Linhui LI Wei HE Yingshuai JIN Peiqi ZhANG Bing XU Chenglong DENG john WOLSEN Zhengtang GUO Xing GAO Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of SciencesBeijing 100044China University of the Chinese Academy of Sciences Beijing 100049China Tibetan Cultural Relics Conservation Institute Lhasa 850000China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of Sciences.Beijing 100029China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China School of Anthropology University of ArizonaTucson85721USA

The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great ***,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool *** two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C *** represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 *** studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya *** contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large *** new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans.

关键词： Tibetan Plateau Paleolithic Nwya Devu High-altitude adaptation Microblade industry Early Upper Paleolithic OSLdating AMS^(14)C dating

Adaptive strategies of high and low nucleic acid prokaryotes in response to declining resource availability and selective grazing by protozoa

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Science China Earth Sciences 2024年第6期67卷 1872-1884页

作者： Chen HU Liuqian YU Xiaowei CHEN Jihua LIU Yao ZHANG john BATT Xilin XIAO Qiang SHI Rui ZHANG Tingwei LUO Nianzhi JIAO Dapeng XU College of the Environment and Ecology Xiamen UniversityXiamen 361102China State Key Laboratory of Marine Environmental Science College of Ocean and Earth SciencesFujian Key Laboratory of Marine Carbon SequestrationXiamen UniversityXiamen 361102China Joint Lab for Ocean Research and Education(LORE)of Dalhousie University Canadaand Shandong University and Xiamen UniversityXiamen 361102China Earth Ocean and Atmospheric Sciences ThrustThe Hong Kong University of Science and Technology(Guangzhou)Guangzhou 510000China Institute of Marine Science and Technology Shandong UniversityQingdao 266237China Department of Oceanography Dalhousie UniversityHalifaxNova Scotia B3H 4R2Canada Institute for Advanced Study Shenzhen UniversityShenzhen 518060China Carbon Neutral Innovation Research Center Xiamen UniversityXiamen 361102China

Prokaryotes play a fundamental role in global ocean biogeochemical ***,how the abundance and metabolic activity of ecologically distinct subgroups(i.e.,high nucleic acid(HNA)and low nucleic acid(LNA)cells),and their regulating factors,change in response to changing marine environmental conditions remains poorly ***,we delved into the time-evolving dynamic responses of the HNA and LNA prokaryotic subgroups to declining resource availability and selective grazing by protozoa by conducting a 73-day incubation experiment in a large-volume(117,000 L)macrocosm that facilitates community-level *** found that the metabolic activity of the HNA subgroup was higher than that of the LNA subgroup when the macrocosm was resource replete but that the HNA subgroup declined more rapidly than the LNA subgroup as the resources became increasingly scarce,leading to a steadily increasing contribution of LNA cells to prokaryotic ***,as resources in the macrocosm became limited,protozoan grazing preference shifted from the HNA to the LNA subgroup and the contributions of the LNA subgroup to the carbon flow within the macrocosm *** findings highlight the resilience of LNA cells in resource-limited environments,illuminate the critical role of selective grazing by protozoa in balancing distinct prokaryotic subgroups under changing resource conditions,and demonstrate the complex and adaptive interactions between protozoa and prokaryotes across diverse environmental contexts.

关键词： Microbial loop Macrocosm experiment Prokaryote Top-down and bottom-up controls Carbon flow

Solid-state Circuit Breaker Based on Cascaded Normally-on SiC JFETs for Medium-voltage DC Distribution Networks

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Protection and Control of Modern Power Systems 2024年第2期9卷 32-46页

作者： Dong He Haohui Zhou Zheng Lan Wei Wang Jinhui Zeng Xueping Yu Z.john Shen Chongqing University of Posts and Telecommunications ChongqingChina Henan Polytechnic University JiaozuoChina College of Electrical and Information Engineering Hunan University of TechnologyZhuzhou 412007China Hunan University ChangshaChina College of Electrical and Information Engineering Hunan UniversityChangshaChina College of Electrical Engineering Three Gorges University Rensselaer Polytechnic Institute TroyNYUSA

Solid-state circuit breakers(SSCBs)are critical components in the protection of medium-voltage DC distribution networks to facilitate arc-free,fast and reliable isolation of DC ***,limited by the capacity of a single semiconductor device,using semi-conductor-based SSCBs at high voltage is *** study presents the details of a 1.5 kV,63 A medi-um-voltage SSCB,composed primarily of a solid-state switch based on three cascaded normally-on silicon car-bide(SiC)junction field-effect transistors(JFETs)and a low-cost programmable gate drive *** and static voltage sharing among the cascaded SiC JFETs of the SSCB during fault isolation is realized using the pro-posed gate drive *** selection conditions for the key parameters of the SSCB gate driver are also ***,an improved pulse-width modulation cur-rent-limiting protection solution is proposed to identify the permanent overcurrent and transient inrush current associated with capacitive load startup in a DC distribu-tion *** the developed SSCB prototype and the fault test system,experimental results are obtained to validate the fault response performance of the *** Terms—Solid-state circuit breaker,DC distribu-tion network,SiC JFET,voltage balancing,inrush current.

关键词： Solid-state circuit breaker DC distribu-tion network SiC JFET voltage balancing inrush current

Metal-metal bonds in Zintl clusters:Synthesis,structure and bonding in[Fe_(2)Sn_(4)Bi_(8)]^(3-)and[Cr_(2)Sb_(12)]^(3-)

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Chinese Chemical Letters 2024年第8期35卷 558-566页

作者： Ya-Nan Yang Zi-Sheng Li Sourav Mondal Lei Qiao Cui-Cui Wang Wen-Juan Tian Zhong-Ming Sun john E.McGrady State Key Laboratory of Element-Organic Chemistry Tianjin Key Lab for Rare Earth Materials and ApplicationsSchool of Materials Science and EngineeringNankai UniversityTianjin 300350China Department of Chemistry University of OxfordInorganic Chemistry LaboratoryOxfordOX13QRUnited Kingdom

We report here the synthesis and characterization of two new members of the M2 E 12 family of endohe-dral Zintl clusters,[Fe_(2)Sn_(4)Bi_(8)]^(3-)and[Cr_(2)Sb_(12)]^(3-),both of which contain open-shell metal dimers encap-sulated inside a triple-decker cluster of main-group *** 75-electron[Fe_(2)Sn_(4)Bi_(8)]^(3-)cluster has a D4h-symmetric structure,while[Cr_(2)Sb_(12)]^(3-),despite having the same 75-electron count,is strongly dis-torted to a geometry that resembles a CrSb_(8)crown capped by a CrSb_(4)*** structural differences between the two are driven by the increasing availability of 3d electron density in the earlier transi-tion metal,which leads,ultimately,to different electronic configurations in the two *** trends precisely mirror those observed in the ME_(10)and ME_(12)families containing a single transition metal ion.

关键词： Zintl anions Endohedral clusters Metal-metal bond Second-order Jahn-Teller effect DFT calculation

Molar ratio induced crystal transformation from coordination complex to coordination polymers

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Chinese Chemical Letters 2024年第4期35卷 539-543页

作者： Peng Meng Qian-Cheng Luo Aidan Brock Xiaodong Wang Mahboobeh Shahbazi Aaron Micallef john McMurtrie Dongchen Qi Yan-Zhen Zheng Jingsan Xu School of Chemistry and Physics&Centre for Materials Science Queensland University of TechnologyBrisbaneQLD 4000Australia Frontier Institute of Science and Technology Xi'an Jiaotong UniversityXi'an 710054China Central Analytical Research Facility Institute for Future EnvironmentsQueensland University of TechnologyBrisbaneQLD 4000Australia

Coordination complex of a copper cyanurate(Cu(Ⅱ)-CA) was transformed into coordination polymers upon the stimulus of extra Cu(Ⅱ) through “directed Ostwald ripening”. By increasing the molar ratio of Cu(Ⅱ) to CA, we obtained two coordination polymers with selective coordination sites: Cu(Ⅱ)-κ N(HCA)κ NCu(Ⅱ) and Cu(Ⅱ)-κ N(HCA)κ O-Cu(Ⅱ), which display disparate magnetic interactions.

关键词： Molar ratio dependent crystal transformation Copper cyanurate Ostwald ripening Molecular magnetism One-dimensional chain

The Decarbonization of Construction—How Can Alkali-Activated Materials Contribute?

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Engineering 2024年第6期37卷 18-21页

作者： john L.Provis Susan A.Bernal Zuhua Zhang Department of Materials Science and Engineering University of SheffieldSheffield S13JDUK Paul Scherrer Institut Villigen PSI 5232Switzerland School of Civil Engineering University of LeedsLeeds LS29JTUK School of Materials Sciences and Engineering Tongji UniversityShanghai 201804China

*** and context Enormous emphasis is currently being paid to the decarbonization of the global built environment as a leading priority for the engineering community and related industrial sectors[1].One of the main contributors to the overall emissions footprint of the built environment-and thus a cornerstone of efforts to achieve decarbonization-is the emissions profile of construction materials during their production and *** cement and concrete sector is the largest-volume contributor to the emissions incurred in meeting the world’s construction material needs and is therefore targeted in the discussion of the deep,rapid decarbonization that must be achieved in order to minimize irreversible damage to the Earth and its ecosystems.

关键词： Alkali corners irreversible