检索结果-南通市图书馆

optimization and Characterization of Cellulose Extraction from Grevillea robusta (Silky oak) Leaves by Soda-Anthraquinone Pulping Using Response Surface Methodology

引用

Green and Sustainable Chemistry 2024年第3期14卷 43-65页

作者： Catherine N. Muya john M. onyari Lydia W. Njenga Joab o. onyango Wilson M. Gitari Department of Chemistry The University of Nairobi Nairobi Kenya School of Chemical and Material Science The Technical University of Kenya Nairobi Kenya

Response surface methodology (RSM) using the central composite design (CCD) was applied to examine the impact of soda-anthraquinone pulping conditions on Grevillea robusta fall leaves. The pulping factors studied were: NaoH charge 5% to 20% w/v, pulping time 30 to 180 minutes, and the anthraquinone charge 0.1 to 0.5% w/w based on the oven-dried leaves. The responses evaluated were the pulp yield, cellulose content, and the degree of delignification. Various regression models were used to evaluate the effects of varying the pulping conditions. The optimum conditions attained were;NaoH charge of 14.63%, 0.1% anthraquinone, and a pulping period of 154 minutes, corresponding to 20.68% pulp yield, 80.56% cellulose content, and 70.34% lignin removal. Analysis of variance (ANoVA), was used to determine the most important variables that improve the extraction process of cellulose. The experiment outcomes matched those predicted by the model (Predicted R2 = 0.9980, Adjusted R2 = 0.9994), demonstrating the adequacy of the model used. FTIR analysis confirmed the elimination of the non-cellulosic fiber constituents. The lignin and hemicellulose-related bands (around 1514 cm−1, 1604 cm−1, 1239 cm−1, and 1734 cm−1) decreased with chemical treatment, indicating effective cellulose extraction by the soda-anthraquinone method. Similar results were obtained by XRD, SEM and thermogravimetric analysis of the extracted cellulose. Therefore, Grevillea robusta fall leaves are suitable renewable, cost-effective, and environmentally friendly non-wood biomass for cellulose extraction.

关键词： Cellulose Extraction Response Surface Methodology Central Composite Design Delignification

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Better engineering layered vanadium oxides for aqueous zinc‐ion batteries: Going beyond widening the interlayer spacing

引用

SmartMat 2024年第1期5卷 83-109页

作者： Yue Guo Hanmei Jiang Binbin Liu Xingyang Wang Yifu Zhang Jianguo Sun john Wang Department of Materials Science and Engineering National University of SingaporeSingaporeSingapore State Key Laboratory of Fine Chemicals School of Chemical EngineeringDalian University of TechnologyDalianChina Institute of Materials Research and Engineering(IMRE) Agency for ScienceTechnology and Research(A*STAR)SingaporeSingapore

Aqueous zinc‐ion batteries(ZIBs)are regarded as among the most promising candidates for large‐scale grid energy storage,owing to their high safety,low costs,and environmental *** the past decade,vanadium oxides,which are exemplified by V2o5,have been widely developed as a class of cathode materials for ZIBs,where the relatively high theoretical capacity and structural stability are among the main ***,there are considerable challenges in the construction of vanadium‐based ZIBs with high capacity,long lifespan,and excellent rate *** widenings of the interlayer spacing in the layered vanadium oxides by pre‐intercalations appear to have reached their limitations in improving the energy density and other key performance parameters of ZIBs,although various metal ions(Na+,Ca2+,and Al3+)and even organic cations/groups have been ***,we discuss the advances made more recently,and also the challenges faced by the high‐performance vanadium oxides(V2o5‐based)cathodes,where there are several strategies to improve their electrochemical performance ranging from the new structural designs down to sub‐nano‐scopic/molecular/atomic levels,including cation pre‐intercalation,structural water optimization,and defect engineering,to macroscopic structural *** key principles for an optimal structural design of the V2o5‐based cathode materials for high energy density and fast‐charging aqueous ZIBs are examined,aiming at paving the way for developing energy storage designed for those large scales,high safety,and low‐cost systems.

关键词： aqueous zinc‐ion batteries cations pre‐intercalation defect engineering structural water vanadium oxides

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Post Episiotomy Morbidity among Parturient in Alex Ekwueme Federal University Teaching Hospital Abakaliki, Ebonyi State

引用

open Journal of obstetrics and Gynecology 2024年第8期14卷 1144-1160页

作者： john Chinedu obasi Ayodele Adegbite olaleye Boniface N. Ejikeme john o. Egede Charles Nwambeke Edene Enemma Christian Enemma Victor onuchukwu Emmanuel onyekelu Nathan C. Ekpe Wendy oliobi Emmanuel C. Uwakwe Department of obstetrics and Gynaecology Alex Ekwueme Federal University Teaching Hospital AbakalikiNigeria

Background: Episiotomy is a very common obstetric surgery, and it could be associated with serious complications. However, these complications largely are not noticed due to the shift of attention from mother to baby, after a successful delivery. objective: To identify the morbidities associated with episiotomies and factors associated with such morbidities. Method: This was a questionnaire based cross sectional descriptive study among women who attended the obstetric Department of Alex Ekwueme Federal University Teaching Hospital Abakaliki Ebonyi State, between 1st July and 31st Nov, 2023. The study population consisted of parturients who had episiotomies in their previous confinements, attending either the antenatal clinic or the postnatal clinic at Alex Ekwueme Federal University Teaching Hospital Abakaliki Ebonyi State. Results: Macrosomia was the most common indication of episiotomy at a rate of 31.6%. The majority of episiotomies were performed on the parturients in their first confinement at a rate of 64.5% and the majority of repairs were performed by the Registrar at a rate of 65.0%. Informed consent was obtained from 45.79% of parturients while 54.21% were not informed before the episiotomy was administered. only 55.3% of the parturient received analgesia before episiotomy was administered. The majority of the parturients had their episiotomy repaired between 10 - 15 minutes at a rate of 40.3%. Postoperative pain at the rate of 44.5% was the most common complication and dyspareunia as a form of sexual complication was the commonest at a rate of 31.3%. Conclusion: The parturient needs to be properly counselled before administration of episiotomy and adequate analgesia should be given, as episiotomy is a surgical procedure. Proper training of health workers on both the technique of administering and repairing episiotomy is important. Restrictive use of routine episiotomy in primigravidae is advised to reduce the rate of episiotomy.

关键词： Episiotomy Vulva Pains Primigravidae Morbidities Analgesia

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Assessment of the performance of the ToPGNSS and ANN-MB antennas for ionospheric measurements using low-cost u-blox GNSS receivers

引用

Geodesy and Geodynamics 2024年第3期15卷 291-301页

作者： Daniel okoh Aderonke obafaye oluwakemi Dare-Idowu Babatunde Rabiu Anton Kashcheyev Claudio Cesaroni john Bosco Habarulema Bruno Nava United Nations African Regional Centre for Space Science and Technology Education-English(UN-ARCSSTE-E) Obafemi Awolowo University CampusIle IfeNigeria National Institute for Geophysics and Volcanology(INGV) 00143 RomeItaly Institute for Space Science and Engineering African University of Science and TechnologyAbujaNigeria University of New Brunswick FrederictonCanada South African National Space Agency(SANSA) P.O Box 32Hermanus 7200South Africa Department of Physics and Electronics Rhodes University6140 MakhandaSouth Africa The Abdus Salam International Centre for Theoretical Physics Strada Costiera11I-34151 TriesteItaly

Low-cost GNSS receivers have recently been gaining reliability as good candidates for ionospheric studies. In line with these gains are genuine concerns about improving the performance of these receivers. In this work, we present a comprehensive investigation of the performances of two antennas(the u-blox ANN-MB and the ToPGNSS ToP-106) used on a low-cost GNSS receiver known as the u-blox ZED-F9P. The two antennas were installed on two identical and co-located u-blox receivers. Data used from both receivers cover the period from January to June 2022. Results from the study indicate that the signal strengths are dominantly greater for the receiver with the ToPGNSS antenna than for the receiver with the ANN-MB antenna, implying that the ToPGNSS antenna is better than the ANN-MB antenna in terms of providing greater signal strengths. Summarily, the ToPGNSS antenna also performed better in minimizing the occurrence of cycle slips on phase TEC measurements. There are no conspicuous differences between the variances(computed as 5-min standard deviations) of phase TEC measurements for the two antennas, except for a period around May-June when the ToPGNSS gave a better performance in terms of minimizing the variances in phase TEC. Remarkably, the ANN-MB antenna gave a better performance than the ToPGNSS antenna in terms of minimizing the variances in pseudorange TEC for some satellite observations. For precise horizontal(North and East) positioning, the receiver with the ToPGNSS antenna gave better results, while the receiver with the ANN-MB antenna gave better vertical(Up) positioning. The errors for the receivers of both antennas are typically within about 5 m(the monthly mean was usually smaller than 1 m) in the horizontal direction and within about 10 m(the monthly mean was usually smaller than 4 m) in the vertical direction.

关键词： GNSS Ionosphere Low-cost Antenna ToPGNSS U-blox

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

黄土高原全新世土壤碳酸盐团簇同位素的温度重建

引用

第四纪研究 2024年第5期44卷 1411-1420页

作者：董吉宝 john EILER 中国科学院地球环境研究所黄土与第四纪地质国家重点实验室陕西西安710061 California Institute of Technology PasadenaCA 91125USA

黄土高原黄土-古土壤序列中保存有丰富的土壤碳酸盐,是利用碳酸盐团簇同位素(Δ_(47))定量重建古温度的重要地质载体之一。然而,黄土高原全新世土壤碳酸盐Δ_(47)及其气候指示意义的系统研究仍然缺乏。本研究分析了黄土高原南缘渭南剖... 详细信息

黄土高原黄土-古土壤序列中保存有丰富的土壤碳酸盐,是利用碳酸盐团簇同位素(Δ_(47))定量重建古温度的重要地质载体之一。然而,黄土高原全新世土壤碳酸盐Δ_(47)及其气候指示意义的系统研究仍然缺乏。本研究分析了黄土高原南缘渭南剖面和中部洛川剖面上部3 m沉积中保存的全新世土壤碳酸盐(钙结核)的团簇同位素组成,监测了现在地形条件下距地表4 m以内不同深度的土壤温度。结果显示,Δ_(47)定量重建的全新世土壤碳酸盐团簇同位素温度(T_(47))与现代暖季节温度相近,渭南剖面T_(47)平均值约为25℃,洛川剖面约为18℃,较区域年均温高8~10℃。根据T_(47)和土壤碳酸盐氧同位素组成(δ18o)重建的土壤水δ18o也与暖季节降水的δ18o基本一致,这些数据表明黄土高原土壤碳酸盐记录了暖季节的环境信息。值得注意的是,渭南和洛川剖面钙结核T_(47)值与其形成深度的土壤温度基本吻合,结合前人研究结果,这暗示了土壤碳酸盐形成深度对其T_(47)具有显著影响。因此,在将来土壤碳酸盐Δ_(47)的研究中,评估土壤碳酸盐形成深度至关重要。

关键词：土壤碳酸盐团簇同位素(Δ_(47)) 全新世黄土高原季节性

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Molar ratio induced crystal transformation from coordination complex to coordination polymers

引用

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

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

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

引用

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

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

放射性药物治疗中的剂量测定

引用

中华核医学与分子影像杂志 2024年第6期44卷 380-384页

作者：杨楠(译) 刘嘉月(审校) 王风(审校) 朱华(审校) 杨志(审校) 北京大学肿瘤医院核医学科北京100142

放射性药物治疗已经在某些疾病中应用,并且该领域正在扩大。近年来,新的治疗性放射性药物已开发出来,更多的药物正在研究中。同时,内照射剂量测量作为一种个性化和潜在优化患者治疗的手段,越来越受到关注。内照射剂量测量是多方面的,该... 详细信息

放射性药物治疗已经在某些疾病中应用,并且该领域正在扩大。近年来,新的治疗性放射性药物已开发出来,更多的药物正在研究中。同时,内照射剂量测量作为一种个性化和潜在优化患者治疗的手段,越来越受到关注。内照射剂量测量是多方面的,该篇继续教育文章讨论了目前的技术状况,主题包括剂量测量的背景、内照射剂量学方法、在放射性药物治疗中纳入剂量测量计算的优缺点、实施患者特异性剂量测量的工作流程描述,并对该领域的未来进行展望。

关键词：放射性核素治疗阿尔法粒子俄歇电子剂量测量法放射生物学放射性药物

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Epidemiology of Mpox outbreaks and Implications for Surveillance in Imo State, Nigeria

引用

Advances in Infectious Diseases 2024年第1期14卷 206-212页

作者： Adeniyi A. Adeniran Ebubechi C. Eronini olugbenga Asaolu Simisola Adedeji Adaeze Joy Ugwu Marcus oludare Faith Ehiaghe Ugba Aibinuomo Ayomide oluwaseyi Tella Adedamola Dania oluyinka olayiwola olanike Suliat oladele Tinuola Daniel Musa Haruna Adebayo o. Amao john o. Ibitoye oluwagbemiga obembe Christopher obanubi Abdulmalik Abubakar Department of Public and Allied Health Babcock University Ilishan-Remo Nigeria Department of Public Health University of Suffolk Waterfront Building UK Department of Public Health EUCLID University Greater Bajul The Gambia Department of Public Health Liverpool John Moores University Liverpool UK College of Medicine Obafemi Awolowo University Ile-Ife Nigeria Department of Environmental Health Sciences University of Ibadan Ibadan Nigeria Department of Public Health Texila American University Georgetown Guyana School of Public Health University of Port Harcourt Port Harcourt Nigeria Department of Community Medicine University College Hospital Ibadan Nigeria Department of Nursing Adeleke University Ede Nigeria Department of Public Health Central University of Nicaragua Managua Nicaragua Faculty of Basic Clinical Sciences Lagos State University College of Medicine Ikeja Nigeria Catholic Relief Services Abuja Nigeria Department of Political Science Faculty of Social Sciences Bayero University Kano Kano Nigeria

Mpox disease is caused by a double-stranded DNA virus, genus orthopoxvirus of the family Poxviridae. The incubation period is usually 6 to 13 days but can range from 5 to 21 days while symptoms and signs may persist for 2 to 5 weeks. Although, the clinical features are usually less severe when compared to the deadly smallpox, the disease can be fatal with case fatality rate between 1% and 10%. In Imo State, Nigeria, there has been a changing epidemiology of the disease in the last 6 years and the frequency and geographic distribution of cases have progressively increased. This study aims to conduct a review of the disease epidemiology between 2017 and 2023 and implications for surveillance in Imo State. Surveillance data from the Surveillance outbreak Response and Management System (SoRMAS) was extracted between January 2017 and December 2023 across the 27 Local Government Areas (LGAs) of Imo State. A line list of 231 suspected cases was downloaded into an excel template and analyzed using SPSS® version 20 software. Analysis was done using descriptive statistics and associations were tested using Fischer’s exact at 0.05 level of significance. of the 231 suspected cases, 57.1% (132) were males, 42.9% (99) were females and the modal age group was between the ages of 0 - 4 (32.5%). Eight (8) LGAs (districts) accounted for 71% (n = 164) of all the suspected cases. 21.2% (49) were confirmed positive, 27 males (55.1%) and 22 females (44.9%) (p > 0.05). Modal age group was 20 - 24 (22.4%, n = 11), 18% (9) were children under 14 years, p > 0.05. Case fatality rate was 8% (n = 4). There was no significant association between mortality and age group. Five (5) LGAs accounted for about 60% (29) of all confirmed cases. These LGAs contribute only 20% to the total population in the State. only 5.6% and 4% of suspected and confirmed cases, respectively, had knowledge of contact with an infectious source. The study described the epidemiology of Mpox outbreaks between 2017

关键词： Mpox Epidemiology outbreak Surveillance

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Magnetohydrodynamic‑based Internal Cooling System for a Ceramic Cutting Tool:Concept Design,Numerical Study,and Experimental Evalidation

引用

Nanomanufacturing and Metrology 2023年第4期6卷 60-80页

作者： john o’Hara Fengzhou Fang Center of Micro/Nano Manufacturing Technology(MNMT-Dublin) University College DublinDublin 4Ireland State Key Laboratory of Precision Measuring Technology and Instruments Laboratory of Micro/Nano Manufacturing Technology(MNMT)Tianjin UniversityTianjin 300072China

The efective removal of the heat generated during mechanical cutting processes is crucial to enhancing tool life and produc-ing workpieces with superior surface *** internal cooling systems used in cutting inserts employ a liquid water-based solvent as the primary medium to transport the excess thermal energy generated during the cutting *** limitations of this approach are the low thermal conductivity of water and the need for a mechanical input to circulate the coolant around the inner chamber of the cutting *** this context,this paper proposes an alternative method in which liquid gallium is used as the coolant in combination with a magnetohydrodynamic(MHD)pump,which avoids the need for an external power *** computational fuid dynamics,we created a numerical model of an internal cooling system and then solved it under conditions in which a magnetic feld was applied to the liquid *** was followed by a simulation study performed to evaluate the efectiveness of liquid gallium over liquid *** results of experiments conducted under non-cooling and liquid gallium cooling conditions were analyzed and compared in terms of the tool wear *** results showed that after six machining cycles at a cutting speed Vc=250 m min−1,the corner wear VBc rate was 75µm with the coolant of and 48µm with the MHD-based coolant on,representing a decrease of 36%in tool *** Vc=900 m min−1,the corner wear VBc rate was 75µm with the coolant of and 246µm with the MHD-based coolant on,representing a decrease of 31%in tool *** external cooling using liquid water was added,the results showed at Vc=250 m min−1,the diference between the tool wear rate reduction with the internal liquid gallium coolant relative to the external coolant was 29%.When the cutting speed was increased to Vc=900 m min−1,the diference observed between the internal liquid gallium coolant relative to the external coolant was 16%.The study proves the feasibility of using liqu

关键词： Internal cooling Heat transfer Liquid metal Magnetic feld Cutting tool

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：