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Natural Science 2022年第8期14卷 343-352页

作者： Karima Ali Hamid Albadawi Abdelbagi Talha Abdalraheem Ali Babiker Mohammed Ibrahim Malik Adam Dawoud Abakar Omer Mustafa Elsidig A Saeed mohmed bushra ahmed Elhadi Abdalla ahmed Department of Histopathology and Cytology Faculty of Medical Laboratory Sciences University of Gezira Wad Medani Sudan Department of Clinical Laboratory Sciences College of Applied Medical Sciences Jouf University Al Jouf Kingdom of Saudi Arabia Department of Medicine Faculty of Medicine University of Gezira Wad Medani Sudan Department of Medical Microbiology Faculty of Medical Laboratory Sciences University of Gezira Wad Medani Sudan

Helicobacter pylori is the microbial agent most responsible for gastro-duodenal ulcer and chronic gastritis, which can develop into carcinoma of the stomach. This study was performed in Wad Medani Teaching Hospital, Sudan to detect Helicobacter pylori in stomach samples, and evaluate the performance of the tests used, which were histological stains and PCR. Gastric biopsies were obtained from 105 referred patients during endoscopy, and fixed specimens examined by haematoxylin-eosin and Warthin-Starry silver stains, while DNA was extracted for glmM gene amplification. Epigastric pain was the most common symptom at 78% (82/105) and chronic gastritis recorded with 71% (68/105) of endoscopy results. Warthin-Starry silver stain gave 31% (33/105) as positive for Helicobacter pylori followed by glmM gene 27% (28/105) and haematoxylin-eosin 24% (25/105). The study indicated good performance of histological staining and high specificity of glmM gene in detection of Helicobacter pylori from gastric biopsies.

关键词： Helicobacter pylori Histological Stains glmM Gene Gastric Biopsy Sudan

Effect of catalyst layer mesoscopic pore-morphology on cold start process of PEM fuel cells

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Frontiers in Energy 2021年第2期15卷 460-472页

作者： ahmed mohmed DAFALLA Fangming JIANG Laboratory of Advanced Energy Systems Guangdong Key Laboratory of New and Renewable Energy Research and DevelopmentCAS Key Laboratory of Renewable EnergyGuangzhou Institute of Energy ConversionChinese Academy of Sciences(CAS)Guangzhou 510640China University of Chinese Academy of Sciences Beijing 100049China

Water transport is of paramount importance to the cold start of proton exchange membrane fuel cells(PEMFCs).Analysis of water transport in cathode catalyst layer(CCL)during cold start reveals the distinct characteristics from the normal temperature *** work studies the effect of CCL mesoscopic pore-morphology on PEMFC cold *** CCL mesoscale morphology is characterized by two tortuosity factors of the ionomer network and pore structure,*** simulation results demonstrate that the mesoscale morphology of CCL has a significant influence on the performance of PEMFC cold *** was found that cold-starting of a cell with a CCL of less tortuous mesoscale morphology can succeed,whereas starting up a cell with a CCL of more tortuous mesoscale morphology may *** CCL of less tortuous pore structure reduces the water back diffusion resistance from the CCL to proton exchange membrane(PEM),thus enhancing the water storage in PEM,while reducing the tortuosity in ionomer network of CCL is found to enhance the water transport in and the water removal from *** the sake of better cold start performance,novel preparation methods,which can create catalyst layers of larger size primary pores and less tortuous pore structure and ionomer network,are desirable.

关键词： cold start energy conversion fuel cells mesoscale morphology tortuosity water management

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Multi-material Bio-inspired Soft Octopus Robot for Underwater Synchronous Swimming

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Journal of Bionic Engineering 2022年第5期19卷 1229-1241页

作者： Faheem ahmed Muhammad Waqas bushra Shaikh Umair Khan Afaque Manzoor Soomro Suresh Kumar Hina Ashraf Fida Hussain Memon Kyung Hyun Choi Department of Mechatronics Engineering Jeju National UniversityJeju 63243South Korea Department of Electrical Engineering Sukkur IBA UniversityAirport RoadSukkur 65200SindhPakistan Advanced Micro Mechatronics and Energy Lab Sukkur IBA UniversitySukkur 65200Pakistan Department of Ocean Sciences Jeju National UniversityJeju 63243South Korea

Inspired by the simple yet amazing morphology of the Octopus, we propose the design, fabrication, and characterization of multi-material bio-inspired soft Octopus robot (Octobot). 3D printed molds for tentacles and head were used. The tentacles of the Octobot were casted using Ecoflex-0030 while head was fabricated using relatively flexible material, i.e., OOMOO-25. The head is attached to the functionally responsive tentacles (each tentacle is of 79.12 mm length and 7 void space diameter), whereas Shape Memory Alloy (SMA) muscle wires of 0.5 mm thickness are used in Octobot tentacles for dual thrust generation and actuation of Octobot. The tentacles were separated in two groups and were synchronously actuated. Each tentacle of the developed Octobot contains a pair of SMA muscles (SMA-α and SMA-β). SMA-α muscles being the main actuator, was powered by 9 V, 350 mA power supply, whereas SMA-β was used to provide back thrust and thus helps to increase the actuation frequency. Simulation work of the proposed model was performed in the SolidWorks environment to verify the vertical velocity using the octopus tentacle actuation. The design morphology of Octobot was optimized using simulation and TRACKER software by analyzing the experimental data of angle, displacement, and velocity of real octopus. The as-developed Octobot can swim at variable frequencies (0.5–2 Hz) with the average speed of 25 mm/s (0.5 BLS). Therefore, the proposed soft Octopus robot showed an excellent capability of mimicking the gait pattern of its natural counterpart.

关键词： Bio-inspired Octopus Octobot Sub-surface Soft robotics Swimming

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空气流量对空冷燃料电池电堆性能的影响研究

化工学报 2022年第7期73卷 3222-3231页

作者：魏琳郭剑廖梓豪 ahmed mohmed Dafalla 蒋方明中国科学院广州能源研究所先进能源系统研究室广东广州510640 中国科学院可再生能源重点实验室广东广州510640 中国科学院大学北京100049

空冷型氢燃料电池采用开放型阴极,具有自增湿、系统简单轻便等特点。为了揭示空气流量对输出性能的影响机制,对自组装的800 W空冷型燃料电池电堆进行了实验测试和数值分析,对比了不同空气风扇转速下电堆输出电压、净功率以及传质传热特... 详细信息

空冷型氢燃料电池采用开放型阴极,具有自增湿、系统简单轻便等特点。为了揭示空气流量对输出性能的影响机制,对自组装的800 W空冷型燃料电池电堆进行了实验测试和数值分析,对比了不同空气风扇转速下电堆输出电压、净功率以及传质传热特性。结果表明:小电流条件下小空气流量可以保持电堆内较高的温度,减少活化损失,实现高净输出功率。然而,大电流条件下,小空气流量将导致电堆温度过高且分布不均匀。利用数值方法对组分和温度分布进行了可视化分析,结果表明低含水量引起的欧姆损失增加是限制输出功率的关键因素,通过提高风扇转速增加空气流量可以保证较好的冷却效果,从而提高含水量,减少欧姆损失。

关键词：燃料电池传热传质水热管理数值分析

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交错布置蜿蜒流道的PEMFC冷启动特性

工程热物理学报 2023年第10期44卷 2798-2807页

作者：廖梓豪魏琳 ahmed mohmed Dafalla 郭剑黄旭锐蒋方明广东电网有限责任公司广州供电局广州510600 中国科学院广州能源研究所广州510640 中国科学院可再生能源重点实验室广州510640 广东省新能源和可再生能源研究开发与应用重点实验室广州510640 中国科学院大学北京100049

质子交换膜燃料电池(PEMFC)在零下温度下的冷启动是影响其市场化的重要障碍。流场构型在一定程度上决定了反应物/生成物的输运,影响着PEMFC的冷启动性能。本研究利用PEMFC冷启动模型,分析了交错布置蜿蜒流道流场(ZFFCA)、蜿蜒流道平行流... 详细信息

质子交换膜燃料电池(PEMFC)在零下温度下的冷启动是影响其市场化的重要障碍。流场构型在一定程度上决定了反应物/生成物的输运,影响着PEMFC的冷启动性能。本研究利用PEMFC冷启动模型,分析了交错布置蜿蜒流道流场(ZFFCA)、蜿蜒流道平行流场(ZPFF)和直通道平行流场(SPFF)的冷启动特性。研究发现,ZFFCA能更好地分布PEMFC内的反应物/生成物、电流密度、热和冰,交错布置的形式更进一步强化了PEMFC的传热传质,有利于冷启动成功;但使用ZFFCA在冷启动过程中PEMFC温度爬升速率较低,不利于快速冷启动。

关键词： PEM燃料电池零下温度冷启动数值仿真流场构型

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夹紧压力对PEMFC冷启动性能的影响

工程热物理学报 2022年第4期43卷 1004-1012页

作者： ahmed mohmed Dafalla 魏琳廖梓豪 BEREKET Tsegai Habte 蒋方明中国科学院可再生能源重点实验室中国科学院广州能源研究所先进能源系统研究室广州510640 中国科学院大学北京100049

质子交换膜燃料电池(PEMFC)作为一种电化学装置,以其高效、低排放、结构紧凑、静音等优点,被认为是未来最具有潜力的发电系统,然而其在低温环境下的快速启动是车用燃料电池面临的重要挑战之一。本文采用有限元法和非等温冷启动数值模型... 详细信息

质子交换膜燃料电池(PEMFC)作为一种电化学装置,以其高效、低排放、结构紧凑、静音等优点,被认为是未来最具有潜力的发电系统,然而其在低温环境下的快速启动是车用燃料电池面临的重要挑战之一。本文采用有限元法和非等温冷启动数值模型对夹紧压力作用下PEMFC的变形及非等温冷启动过程进行了求解,分析了扩散层厚度及非均匀变形对传质传热、电流密度和冰分布以及输出电压特性的影响。结果表明,扩散层非均匀变形会增加脊下区域传质阻力,加剧氧气的不均匀分布,而位于通道下区域的阴极催化层内的反应更加剧烈,使得PEMFC升温更快,且当夹紧压力为1~2 MPa时冷启动性能最佳。

关键词：质子交换膜燃料电池夹紧压力冷启动气体扩散层数值模拟

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Salinity Stress in Wheat:Effects,Mechanisms and Management Strategies

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Phyton-International Journal of Experimental Botany 2022年第4期91卷 667-694页

作者： Mahmoud F.Seleiman Muhammad Talha Aslam bushra ahmed Alhammad MuhammadUmair Hassan Rizwan Maqbool Muhammad Umer Chattha Imran Khan Harun Ireri Gitari Omer S.Uslu Rana Roy Martin Leonardo Battaglia Plant Production Department College of Food and Agriculture SciencesKing Saud UniversityRiyadh11451Saudi Arabia Department of Crop Sciences Faculty of AgricultureMenoufia UniversityShibin El-kom32514Egypt Department of Agronomy University of AgricultureFaisalabad38040Pakistan Biology Department College of Science and Humanity StudiesPrince Sattam Bin Abdulaziz UniversityRiyadh11942Saudi Arabia Research Center on Ecological Sciences Jiangxi Agricultural UniversityNanchang330045China Department of Agricultural Sciences and Technology School of Agriculture and Enterprise DevelopmentKenyatta UniversityNairobi00100Kenya Department of Field Crops Faculty of AgricultureUniversity of Sutcu ImamKahramanmaras46040Turkey Department of Agroforestry&Environmental Science Faculty of AgricultureSylhet Agricultural UniversitySylhet3100Bangladesh Department of Animal Sciences Cornell UniversityIthaca14850USA

Salinity stress is a major threat to global food production and its intensity is continuously increasing because of anthropogenic *** is a staple food and a source of carbohydrates and calories for the majority of people across the ***,wheat productivity is adversely affected by salt stress,which is associated with a reduction in germination,growth,altered reproductive behavior and enzymatic activity,disrupted photosynthesis,hormonal imbalance,oxidative stress,and yield ***,a better understanding of wheat(plant)behavior to salinity stress has essential implications to devise counter and alleviation measures to cope with salt *** approaches including the selection of suitable cultivars,conventional breeding,and molecular techniques can be used for facing salt stress ***,these techniques are tedious,costly,and *** practices are still helpful to improve the wheat performance under salinity *** of arbuscular mycorrhizal fungi,plant growth-promoting rhizobacteria,and exogenous application of phytohormones,seed priming,and nutrient management are important tools to improve wheat performance under salinity *** this paper,we discussed the effect of salinity stress on the wheat crop,possible mechanisms to deal with salinity stress,and management options to improve wheat performance under salinity conditions.

关键词： Breeding techniques oxidative stress photosynthesis phyto-hormones salinity stress wheat

Knowledge Attitude and Practice towards Antenatal Care among Pregnant Women Attending for Antenatal Care in SOS Hospital at Hiliwa District, Benadir Region, Somalia

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Health 2022年第4期14卷 377-391页

作者： Abdullahi Muse Mohamoud Sahra Mire Mohamed ahmed Mohamud Hussein Maida Abshir Omar bushra Mohamud Ismail Rahma Abdulahi Mohamed Muna Ishaq ahmed Seynab Dahir Ibrahim Faculty of Health Sciences Benadir University Mogadishu Somalia PHC & HE Faculty of Medicine University of Gezira Wad Madani Sudan Faculty of Medicine and Health Sciences Mogadishu University Mogadishu Somalia

Background: Antenatal care is one of the strategies aimed at addressing maternal mortality as it facilitates the identification and avoid pregnancy related problems and save lives of mothers and babies. Purpose: This study aimed knowledge attitude and practice towards antenatal care among pregnant women attending for antenatal care in SOS Hospital, Hiliwa District, Benadir region, Somalia during the period of the study from April 2021-July 2021. Methodology: The study was descriptive cross-sectional, retrospective hospital based;a total of 60 of pregnant women were enrolled in this study. Data were collected through interview method using structured questionnaire. Data analysis was used Statistical Package for Social Science version 20 for analysis (SPSS). Results: The study discovered a total of 60 respondents have participated of which 45 (75%) had knowledge towards antenatal care, while the study found that the sources of antenatal care information was;23 (38%) from health care providers at health centers and 10 (17%) from husbands. Among the study respondents 48 (80%) have convenience and accepted the utilization of antenatal care and a total of 51 (85%) were seeking permission for antenatal care visit. Also study respondents about 35 (58%) utilized antenatal care visit during their previous pregnancies and 25 (42%) did not. About 22 (36%) were preferred mother and child health centers, 10 (16%) were preferred public hospitals and few proportion 2 (5%) were preferred private hospital for antenatal care visit respectively. Finally the study showed that, multigravida, gestational months, seeking permission and spouse accompany to the antenatal care visit and level of awareness significantly contributed to the utilization of ANC by pregnant women in this study. Significant difference was strongly observed (P = 0.000). Conclusion and Recommendations: In conclusion, there was good knowledge and positive attitude towards ANC despite poor antenatal care utilization, th

关键词： ANC Pregnancy Related Problems SOS Hospital Hiliwa

Outcomes of Pregnancy with Group B Streptococcal Infections in Najran, Saudi Arabia

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Open Journal of Obstetrics and Gynecology 2023年第3期13卷 395-402页

作者： Majed Saeed Alshahrani Ali H. Alhajri Fahad Thamer Almutairi Ashwag Hassan Abdelmajed Fatima Ibrahim Abdalla Yousra Bala Babkir Abdullah Mosab Mohamedelamineltaib ahmed Faroug ahmed Abdelaal Mohamed ahmed Mukhtar Mowafag bushra Galaleldin Elsayed Marwa Mohamed ahmed Elkhidir Babikir Nihal Altayeb Abdallah Selma Mohammed Abdelgadir Elhabeeb Department of Obstetrics and Gynecology College of Medicine Najran University Najran Saudi Arabia Najran Armed Forces Hospital Najran Saudi Arabia

Background: The gram-positive, beta-hemolytic, and chain-forming Group B Streptococcus (GBS), commonly known as Streptococcus agalactiae, may asymptomatically invade the human gastrointestinal and vaginal tracts. However, GBS may become very invasive and pathogenic to the mother and baby during pregnancy, having negative effects. Study Aim: This study aims to investigate the pregnancy outcomes of women who tested positive for genitourinary GBS infection during pregnancy in Najran, Saudi Arabia. Methods: Data was collected retrospectively from patient files in Armed Forces Hospital, Najran, Saudi Arabia. Data collected were entered to a Microsoft Excel sheet, then imported and analysed using the Statistical Package for Social Sciences. Results: The study included 272 women of whom 66.5% were 31 to 45 years old. Gestational diabetes was diagnosed in 8.5% of the sample, 71.7% had a normal spontaneous vaginal delivery (NSVD), 1.8% had previous abortions, and 27.2% of new-borns were admitted to the NICU after delivery. There was a significant association between NICU admissions and women employment status (p = 0.001), gravidity (p = 0.001), parity (p = 0.001), history of abortions (p = 0.001), medical conditions (p = 0.049), and mode of delivery (p = 0.049). Conclusion: According to the findings of our study, GBS infection during pregnancy is associated to more NICU admissions. NICU admissions were significantly correlated with gestational diabetes, hypertension, and hypothyroidism in mothers but not with intrapartum antibiotic use.

关键词： Pregnancy Group B Streptococcal Outcomes

Determination Uranium Concentrations and Effective Dose of Drinking Water for Nineveh Governorate—Iraq, Using Kinetic Phosphorescence Analyzer (KPA)

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Journal of Environmental Protection 2014年第3期5卷 200-206页

作者： Shafik Shakier Shafik bushra Ali ahmed Mazin Mohammed Department of Physics College of Science University of Baghdad Baghdad Iraq Ministries of Environment Radiation Protection Center Baghdad Iraq

In this work, the concentrations of natural Uranium and the annual effective dose (ET in Sv·y-1) in drinking water for Nineveh Governorate in northern Iraq were determined using a pulsed-laser Kinetic Phosphorescence Analyzer (KPA). Furthermore, the relationship between pH for water samples and the concentration of Uranium was studied. The drinking water samples are taken approximately from all regions of Nineveh as;15 samples of tap water are taken from refinery stations, 13 samples of water samples are taken from wells that are used for drinking, and 18 samples of drinking water are withdrawn from wells in Adayyah region (this region is located near nuclear wastes site). Thus, the total studied samples are 46. The results of Uranium concentration for all samples ranged from 2.61 ± 0.08 to 9.14 ± 0.012 μg·L-1 with an overall average value about 5.87 ± 0.046 μg·L-1, and the total annual effective dose ranged from 2.3 to 8.04 μSv·y-1. The results also showed that the pH number increases with increasing Uranium concentration and have, in general, high values in well water.

关键词： Uranium KPA Drinking Water Intake Annual Effective Dose Nineveh