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

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

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Global lessons on delivery of primary healthcare services for people with non-communicable diseases:convergent mixed methods

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Family Medicine and Community Health 2024年第3期12卷 13-24页

作者： Robert Mash Lisa R Hirschhorn Inayat Singh Kakar Renu john Manushi Sharma Devarsetty Praveen Stellenbosch University StellenboschSouth Africa Northwestern University ChicagoIllinoisUSA The George Institute for Global Health New DelhiIndia The George Institute for Global Health HyderabadIndia Manipal Academy of Higher Education ManipalIndia

Objective To extract key lessons on primary healthcare(PHC)service delivery strategies for non-communicable diseases(NCD)from the work of researchers funded by the Global Alliance for Chronic Diseases(GACD).Design A convergent mixed methods study that extracted data using a standardised template from research projects funded by the GACD that focused on *** strategies implemented in these studies were mapped onto the PHC Performance Initiative *** qualitative interviews were conducted with researchers from purposefully selected projects to understand the strategies and contextual factors in more *** PHC contexts from low or middle-income countries(LMIC)as well as vulnerable groups within high-income *** came from all regions of the world,particularly East Asia and Pacific,sub-Saharan Africa,South Asia,Latin America and *** The study extracted data on 84 research projects and interviewed researchers from 16 research *** Research projects came from all regions of the world,and mainly focused on diabetes(35.3%),hypertension(28.3%)and mental health(27.6%).Mapped onto the PHC Performance Initiative framework:49.4%focused on high-quality PHC(particularly the comprehensiveness of NCD care,41.2%);41.2%on the availability of PHC services(particularly the competence of healthcare workers,36.5%);35.3%on population health management(particularly community-based services,35.3%);34.1%on facility organisation and management(particularly team-based care,20.0%)and 31.8%on access(particularly digital technology,23.5%).Most common strategies were task shifting and training to improve the comprehensiveness of NCD care through community-based *** factors related to inputs:infrastructure,equipment and medication,workforce(particularly community health workers),finances,health information systems and digital *** Key strategies and contextual factors to improve PHC service del

关键词： services convergent income

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What makes residents participate in the rural toilet revolution?

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Environmental Science and Ecotechnology 2024年第3期19卷 23-25页

作者： Yong Li Shikun Cheng Xingyu Chen Mingjun Gao Cong Chen Elisabeth-Maria Huba Zifu Li john Crittenden Tianxin Li School of Energy and Environmental Engineering Beijing Key Laboratory of Resource-oriented Treatment of Industrial PollutantsUniversity of Science and Technology BeijingXueyuan Road No.30Haidian DistrictBeijing100083PR China School of Economics and Management University of Science and Technology BeijingXueyuan Road No.30Haidian DistrictBeijing100083PR China German Toilet Organization Paulsenstr.2312163BerlinGermany Brook Byers Institute for Sustainable Systems Georgia Institute of TechnologyAtlanta30332GAUnited States

Recent data reveals a staggering reality:as of 2020,approximately 3.6 billion individuals across the globe remain devoid of proper sanitation services[1].Worldwide governmental and nongovernmental organisations are dedicatedly engaged in the arduous task of ameliorating living standards by providing secure sanitation ***,a recurring challenge persists,with these initiatives frequently encountering setbacks,especially in rural areas.

关键词： services governmental rural

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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

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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

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Pattern of Referral of Obstetric Patients at a Tertiary Care Hospital in Southern Nigeria

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Advances in Reproductive Sciences 2024年第2期12卷 116-124页

作者： Osita Celestine john Justina Omoikhefe Alegbeleye Department of Obstetrics and Gynaecology Faculty of Clinical Sciences University of Port Harcourt Port Harcourt Nigeria

Background: Health challenges that are difficult to manage at primary health centres should be referred to secondary health facilities, and if untreated, to the tertiary hospitals. A good referral should include the patient’s biography, such as age, gender, tribe, religion, occupation, medical history, the reason for the referral, treatments received, and clinical diagnosis. Objectives: To evaluate the referral patterns, indications for referrals, and feto-maternal outcomes for obstetric patients who were referred to the University of Port Harcourt Teaching Hospital. Materials and Methods: A prospective study of patients admitted to the Obstetric unit from January 1, 2021, to December 31, 2022. Data was collected from patients while on admission or clinic visits and recorded in an excel spread sheet. Data was analyzed with the Statistical Package for Social Sciences (SPSS) version 25. Results: Of the 3469 patients were admitted to the obstetric unit, 1476 and 1993 were admitted in 2021 and 2022, respectively. Most (70.35%) of the patients were in the 20-34 years age group, parity 1-4 was the most frequent (66.49%), while 85.39% of patients were booked. 10.46% of the booked patients were referred from other facilities, whereas 89.54% of patients were booked at our facility from the onset. Most common indications of referrals were previous caesarean section (CS) at term (40.09%) and hypertensive disorders of pregnancy (17.59%). The outcome for 2021 indicated 17 maternal deaths, 132 fetal deaths and 1010 live births, giving maternal mortality ratio (MMR) as 1810.44 per 100,000 live births and perinatal mortality ratio (PMR) of 130.7 per 1000 births respectively. In 2022, there were 17 maternal deaths, 130 fetal deaths and 1297 deliveries, giving a MMR of 1399 per 100,000 live births and a PMR of 100.2 per 1000 births. Conclusion: The pattern of referral among obstetric patients in this study shows that a lot of the patients do not get adequate care at the lower cadre o

关键词： Referral Pattern Obstetrics Southern Nigeria

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Eclampsia: A Continuous Scourge in a Tertiary Hospital in Southern Nigeria

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Open Journal of Obstetrics and Gynecology 2024年第1期14卷 209-225页

作者： Celestine Osita john Justina Omoikhefe Alegbeleye Department of Obstetrics and Gynaecology Faculty of Clinical Sciences University of Port Harcourt Port Harcourt Nigeria

Background: Eclampsia is responsible for over 50,000 maternal deaths with incidence of 1 death in about 100 - 1500 deliveries in developing nations. In sub-Saharan Africa, Nigeria accounts for the highest maternal mortality ratio of 512 deaths per 100,000 live deliveries and the highest neonatal fatality of 67 per 1000 live births. Factors such young age, nulliparity, multifetal gestation, unbooked cases, preterm delivery (<32 weeks), lack of proper access to antenatal care, poor hospital care, financial constraints and inappropriate diagnosis, have all been identified as risk factors promoting eclampsia. Objectives: In this study, we investigated the prevalence of eclampsia in Rivers State, Nigeria and established the correlation between social demographic factors and the feto-maternal outcomes among the eclampsia patients. Methodology: A prospective observational study using a detailed data sheet was conducted on 1244 pregnant women admitted at the Obstetrics and Gynecology Department of University of Port Harcourt Teaching Hospital, for 1-year duration. Data analysis was conducted using statistical packages for social sciences (SPSS) version 22. Results: Demography showed that age range (20 - 24) occurred in 40.7%, nulliparous mothers were dominant with 40.7% while 70.1% of the study population had secondary level of education. 27 cases of eclampsia were diagnosed from the 1244 pregnant women, which signified 2.13% prevalence among the studied population. The feto-maternal outcome showed that out of the 27 mothers, 19 were alive (70.4%) while 8 died (29.6%), while fetal outcome showed that 16 were alive (59.3%) and 11 died (40.7%). Only parity and education showed significant correlation at 0.01 and 0.05 levels respectively with maternal outcome. Conclusion: The prevalence of eclampsia with associated poor feto-maternal outcome rates is high in this study. Its contribution to the maternal and perinatal morbidities and mortalities necessitates the narrative of ecl

关键词： Eclampsia Preeclampsia Prevalence Maternal Fetal Mortality Booked Un-booked

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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

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The Use of Glycated Albumin in the Diagnosis of Gestational Diabetes Mellitus

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Journal of Biosciences and Medicines 2024年第1期12卷 19-28页

作者： Atochi Prince Woruka Celestine Osita john Obstetrics and Gynecology Department University of Port Harcourt Teaching Hospital Port Harcourt Nigeria Obstetrics and Gynecology Department University of Port Harcourt Port Harcourt Nigeria

Gestational diabetes mellitus is the most common endocrine disorder in pregnancy and a cause of maternal and fetal morbidities and mortalities. The oral glucose tolerance test is the gold standard for diagnosing gestational diabetes mellitus. Nevertheless, the oral glucose tolerance test is time-consuming and requires patient preparation. On the contrary, Glycated albumin does not require patient preparation or administration of any substance. Most studies on glycated albumin in pregnancy were among the non-African population, and black Americans have higher glycated albumin levels than Caucasians. This study determined the use of glycated albumin in diagnosing gestational diabetes mellitus among pregnant women. The study was a prospective study of 160 pregnant women between 24 and 28 weeks of gestation at the University of Port Harcourt Teaching Hospital. The diagnosis of gestational diabetes mellitus was based on the World Health Organization 2013 criteria. The diagnostic value of glycated albumin was determined using the area under the receiver operator characteristic curve. The prevalence of gestational diabetes mellitus was 9.4% and the mean glycated albumin was 16.91% (±2.77). The area under the receiver operator characteristic curve for glycated albumin was 0.845 (95% CI 0.733 - 0.956;p = 0.0001). The optimal cut-off value of glycated albumin in the diagnosis of gestational diabetes mellitus was 18.9%. Glycated albumin was useful in the diagnosis of gestational diabetes mellitus at 24 to 28 weeks of gestation.

关键词： Glycated Albumin Gestational Diabetes Mellitus Oral Glucose Tolerance Test University of Port Harcourt Teaching Hospital

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Literature Review of the Prevalence of Hypertension at Gulu University, Gulu City, Acholi Subregion, Northern Uganda

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World Journal of Cardiovascular Diseases 2024年第9期14卷 588-602页

作者： Lamwaka Alice Veronica Mboowa john Bosco Department of Pharmacy Faculty of Medicine Gulu University Gulu City Uganda

Hypertension is a big problem worldwide. The purpose of this study is to examine the prevalence, knowledge, attitude, and practice about hypertension at Gulu University, Gulu city, Gulu district, Acholi subregion, Northern Uganda. A literature search on hypertension was done. It showed that, in Uganda, a representative number of 17,777 adult patients’ data were analyzed from January 2014 to February 2024. The epidemiological data on awareness of hypertension was found to be at 8%. Of this, 18.3% of the people with hypertension had it under control. The results of the findings were promising. Hypertension is an important public health challenge in Uganda particularly in Northern Uganda where Gulu University falls. In comparison with the two regions of Central Uganda and Northern Uganda, there was a significant number of populations that were not aware of their condition. Those diagnosed were on treatment but the treatment was not adhered to due to stock outs of medicines. Therefore, Measures are required to prevent hypertension, improve awareness, treatment and control within the community, especially at Gulu University where research has never been done.

关键词： Prevalence Hypertension Blood Pressure Knowledge Attitude Practices Cross Sectional Studies

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