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Fabrication, Microstructure, Thermal and Electrical Properties of Copper Heat Sink Composites

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Materials Sciences and Applications 2016年第9期7卷 542-561页

作者： Walid Daoush Ahmed Swidan gamal Abd El-Aziz mohamed Abdelhalim Department of Production Technology Faculty of Industrial Education Helwan University Cairo Egypt Present Address: Department of Chemistry Faculty of Science Al-Imam Muhammad Ibn Saud Islamic University Al Riyadh KSA Mechanical Department Ameeria Integrated Technical Cluster Cairo Egypt Mechanical Department Faculty of Industrial Education Suez University Suez Egypt

Copper as well as copper base composites reinforced with coated and uncoated 1 wt% diamond, graphite particles or short carbon fibers are prepared by powder metallurgy process. The reinforcement particles were encapsulated with silver as well as copper layer by using the electroless deposition technique to investigate the influence of the reinforcement surface coating on the microstructure, density, electrical and thermal properties of the sintered samples. The coated and the uncoated powders were cold compacted at 600 MPa, and then sintered at 1173 K (900°C) for 2 h under hydrogen atmosphere. The phase composition, morphology and microstructure of the prepared powders as well as the copper base sintered composites were investigated using X-ray diffraction analysis (XRD) and Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS) respectively. The density of the sintered composites was measured by Archimedes method. The copper base consolidated composites had a density up to 96% and the reinforcement coated particles were distributed uniformly within the copper matrix better than the uncoated one. The electrical resistivity at room temperature and the heat transfer conduction of the produced samples were measured in a temperature range between 323 K (50°C) and 393 K (120°C). The results observed that the sintered materials prepared from the coated powder have lower electrical resistivity than the sintered materials prepared from the mixed powders. On the other hand the thermal conductivity values were calculated using the heat transfer conduction values by means of the Fourier formula. The results observed that the thermal conductivity of copper is (391 W/m·K), 1 wt% diamond/Cu is (408 W/m·K), 1 wt% graphite coated silver/Cu is (393 W/m·K), 1 wt% Cu coated short carbon fiber/Cu is (393 W/m·K), graphite/Cu is (383 W/m·K) and short carbon fiber/Cu is (382 W/m·K). The obtained compos

关键词： Heat Sink Powder Metallurgy Matrix Composites Electrical Resistivity Thermal Conductivity Natural Forced Convection

Computational Study of Resonantly Ionizing Rubidium Vapor by Nanosecond Laser Pulses

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Journal of Modern Physics 2012年第9期3卷 927-934页

作者： mohamed Abd El-Hameid Mahmoud Yosr Ez El Din gamal Department of Physics Faculty of Science Sohag University Sohag Egypt Department of Physics Girls’ Faculty of Science King Abdul-Aziz University Jeddah KSA

An investigation of the resonant interaction of the rubidium atoms with an intensity (10 kWcm-2 ≤ I ≤ 2 MWcm-2) and a wavelength close to that of the D1 and D2 transitions of the rubidium atom (5S1/2 → 5P3/2 or 5S1/2 → 5P1/2, λD1 = 780 nm, λD2 = 795 nm), which has passes through rubidium vapor with density (1011 - 1014 cm-3) been studied theoretically. The system of equations describing the processes of Collisional ionization and multiphoton ionization of rubidium vapour resonantly excited with nanosecond pulsed laser is solved. The dependence of the ion density on the laser intensity and the atomic density of rubidium are considered. The result of calculations revealed that, both quadratic ion density dependence on laser intensity and linear behaviour of the ion density versus rubidium density for 5S1/2 → 5P3/2 transition is due to photoioization process. In contrast, for 5S1/2 → 5P1/2 transition, the ion density dependence is nonlinear and indicates that the collisional processes play the major contribution in the total ionization. Also, the obtained results showed reasonable agreement with the experimentally measured values of the ion density dependence given by Bakhramov et al. In addition, the analysis of mutual competition between the different ionization processes considered for the ion yield as a function of both laser intensity and atoms density are also presented this work.

关键词： Laser Plasma Collisional Ionization Electron Energy Distribution Function Photoionization Rubidium

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番茄非特异性脂质转移蛋白的鉴定与表达分析

番茄非特异性脂质转移蛋白的鉴定与表达分析

作者： ALAA gamal mohamed FERIG ABOUSHANAB 华中农业大学

学位级别：硕士

在植物中,非特异性脂质转移蛋白(nsLTPs)是一类小的碱性蛋白(6.5至10.5KD),由多基因家族编码,它们参与多种生理生化过程。脂质转移蛋白(LTP)具有转移或结合不同类型的疏水性分子例如脂肪酸,磷脂,脂肪酰基-Co A,糖脂和角质单体的能力,NsL... 详细信息

在植物中,非特异性脂质转移蛋白(nsLTPs)是一类小的碱性蛋白(6.5至10.5KD),由多基因家族编码,它们参与多种生理生化过程。脂质转移蛋白(LTP)具有转移或结合不同类型的疏水性分子例如脂肪酸,磷脂,脂肪酰基-Co A,糖脂和角质单体的能力,NsLTPs通常包含ECM结构域。我们通过数据库和基因组分析,利用Blast搜索,我们在番茄中鉴定了仅含有编码ECMS域,并且没有其他可识别的功能结构域的非特异性脂质转移蛋白,总共38个基因被鉴定为nsLTPs。我们进一步研究了该基因家族的基因结构,染色体位置,功能注释和进化关系。此外,我们分析了这些基因的顺式元件,研究了在不同非生物逆境和激素处理条件下的表达谱情况。这些对SlnsLTPs基因家族的研究为揭示它们潜在的功能提供了一个线索。

关键词： Tomato Gene expression NsLTP Abiotic stress

Regional Evaluation of GOCE-Based GGMs with Ground-Based Gravity and GPS/Levelling Data over Egypt

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International Journal of Geosciences 2019年第6期10卷 652-668页

作者： Ahmed Saadon Basem Elsaka mohamed El-Ashquer gamal El-Fiky Construction Engineering and Utilities Department Faculty of Engineering Zagazig University Zagazig Egypt National Research Institute of Astronomy and Geophysics (NRIAG) Cairo Egypt Institute of Geodesy and Geoinformation University of Bonn Bonn Germany The Bilbies Higher Institute of Engineering Bilbies Egypt

The gravity field and steady-state ocean circulation explorer (GOCE) satellite mission has provided numerous Global Geopotential Models (GGMs) with different processing methodologies and model accuracies. In the current contribution, the latest releases of GOCE-based GGMs are evaluated on the regional scale using the available terrestrial GPS/Levelling and gravity data collected over Egypt. To overcome the spectral inconsistency between the GOCE-based GGMs and the ground-based data, the spectral enhancement method (SEM) is applied. Five of GOCE-based GGMs have been used, namely GOSG01S, IGGT_R1, IfE_GOCE05s_ GO_CONS_GCF_2_SPW_R5 (SPW_R5 in the following) and NULP-02. The evaluation process of GOCE-based GGMs with the available ground data over Egypt considering the SEM method shows remarkable improvements obtained from the SPW_R5 model. The model provides lower differences of the standard deviations with respect to the EGM2008 and the other applied geopotential gravity models as well as the applied ground-based gravity and GPS/Levelling data. The findings regarding the ground-based data show obvious reductions of about 15.16% and 32.22% achieved by the GOCE-based model in term of standard deviations differences of gravity anomalies and geoid heights, respectively. Therefore, the SPW_R5 model is recommended to be applied as a reference model for compensating the long-to-short wavelength (up to spherical harmonics degree/order 280) components when modelling the gravimetric geoid over Egypt.

关键词： GOCE-Based GGMs Gravity Anomalies GNSS/Levelling Spectral Enhancement Method (SEM)

Development of NIS Two-Temperature Humidity Generator

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Journal of Physical Science and Application 2014年第7期4卷 436-439页

作者： mohamed gamal Ahmed Said Mazen Doaa Abd El-Gelil National Institute for Standard Giza Egypt Physics Department Faculty of Science Zagazig University Sharkia Egypt

Abstract： This paper describes the development and characterization of a two-temperature （2-T）, constant pressure humidity generator It relies on the saturation of a stream of gas flowing over a water surface maintained at constant, well-known, temperature. It was built in order to improve the uncertainties of the dew-point temperature and humidity scales realization at the National Institute for Standard （NIS） in the dew-point range from -50 ℃ to ＋ 10 ℃. Several experiments were carried out in the above mentioned range in order to characterize the generator. Characterization comprised studies of its saturator efficiency, temperature stability and a comparison with a calibrated chilled-mirror hygrometer. The results of the efficiency tests showed good performance of the generator as described below. For uncertainty of measurements, a thorough analysis was also described representing estimations of contributions for all the sources that affecting measurements.

关键词： Dew-point hygrometer two-temperature generator uncertainty.

Trends and outcomes of pancreaticoduodenectomy for periampullary tumors: A 25-year single-center study of 1000 consecutive cases

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World Journal of Gastroenterology 2017年第38期23卷 7025-7036页

作者： ayman el nakeeb waleed askar ehab atef ehab el hanafy ahmad m sultan tarek salah ahmed shehta mohamed el sorogy emad hamdy mohamed el hemly ahmed a el-geidi tharwat kandil mohamed el shobari talaat abd allah amgad fouad mostafa abu zeid ahmed abu el eneen nabil gad el-hak gamal el ebidy omar fathy ahmed sultan mohamed abdel wahab gastroenterology surgical center mansoura university

AIM To evaluate the evolution, trends in surgical approaches a n d r e c o n s t r u c t i o n t e c h n i q u e s, a n d i m p o r t a n t lessons learned from performing 1000 consecutive pancreaticoduodenectomies(PDs) for periampullary *** This is a retrospective review of the data of all patients who underwent PD for periampullary tumor during the period from January 1993 to April 2017. The data were categorized into three periods, including early period(1993-2002), middle period(2003-2012), and late period(2013-2017).RESULTS The frequency showed PD was increasingly performed after the year 2000. With time, elderly, cirrhotic and obese patients, as well as patients with uncinate process carcinoma and borderline tumor were increasingly selected for PD. The median operative time and postoperative hospital stay decreased significantly over the periods. Hospital mortality declined significantly, from 6.6% to 3.1%. Postoperative complications significantly decreased, from 40% to 27.9%. There was significant decrease in postoperative pancreatic fistula in the second 10 years, from 15% to 12.7%. There was a significant improvement in median survival and overall survival among the *** Surgical results of PD significantly improved, with mortality rate nearly reaching 3%. Pancreatic reconstruction following PD is still debatable. The survival rate was also improved but the rate of recurrence is still high, at 36.9%.

关键词： Pancreaticoduodenectomy Pancreaticogastrostomy Pancreaticojejunostomy Postoperative pancreatic fistula Periampullary tumor

The Radiological Outcome of Surgical Correction of Hallux Valgus with Combined Scarf and Akin Osteotomies

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Open Journal of Orthopedics 2023年第3期13卷 84-96页

作者： Sami Nogdallah mohamed Alhassan Osman Montaser Fatooh Alaa mohamed mohamed Khairy Hozifa Mohammed Ali Abd-Elmaged Osama gamal Nubi Orthopedics Surgery Department Alneelain University Khartoum Sudan Bashaer Teaching Hospital Khartoum Sudan Orthopaedic Registrar Sudan Medical Specialization Board Khartoum Sudan Orthopedics Surgery Department Alzaiem Alazhari University Khartoum Sudan Bashaer University Hospital MBBS Al Neelan University Khartoum Sudan

Background: Hallux valgus deformity is one of the most common chronic and progressive foot deformities. Surgical correction of the deformity plays a central role in the treatment of symptomatic hallux valgus. However, more than one hundred different surgical techniques have been described. Objective: To assess the radiological outcome of hallux valgus surgical correction using a scarf and akin osteotomies. Materials and methods: A cross-sectional hospital-based study was conducted on 25 adult patients (36 feet). Twenty-two females and two males with hallux valgus were treated with surgical correction using a scarf and akin osteotomies. All candidates were kept on regular postoperative, scheduled clinical follow-up programs for one year and assessed radiologically. Results: Twenty-five patients (36 feet) were included in this study. The hallux valgus angle significantly shifted to the normal range (less than 15°) after surgery, and the inter-metatarsal angle also improved to the normal range (less than 9°). Conclusion: Using scarf and akin osteotomies in treating moderate and severe hallux valgus deformity provides the satisfactory radiological outcomes in form of decreasing hallux valgus angle and inter-metatarsal angle.

关键词： Hallux Valgus Scarf Osteotomy Akin Osteotomy Valgus Angle Intermetatarsal Angle

Nutritional Profile of Children with Major Sickle Cell Syndrome at the Centre of Medical and Health Advice of Kipé, Conakry, 2018

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Case Reports in Clinical Medicine 2024年第3期13卷 73-84页

作者： Mamadou Aliou Doukoure Ibrahima Sory Diallo M’mah Aminata Bangoura Amadou Oury Toure Mamadou Moustapha Diop Fatoumata Binta Diallo mohamed Sama Cherif Thierno Saidou Diallo Saidouba Cherif Camara Abdoulaye Toure Faculty of Health Science and Technology Gamal Abdel Nasser University Conakry Guinea National AIDS Control Programme Ministry of Health Gamal Abdel Nasser University Conakry Guinea

Introduction: Growth is a reflection of a child’s health and nutritional status. Children with sickle cell disease often have slower statural and weight development. The aim of this study was to evaluate the nutritional profile of children with sickle cell disease (SCD) registered in the CEMECO centre database. Methodology: This was a cross-sectional study with simple random sampling of children aged 1 to 16 years registered in the clinic database. Results: We collected information on 208 children, 121 of whom had sickle cell disease and 87 of whom were normal, with a sex ratio of 1.02. The mean age of the sickle cell patients was 8.7 ± 4.4 years, while that of the non-sickle cell patients was 9.5 ± 4 years. Haemoglobin electrophoresis revealed 103 homozygous (SS), 18 double heterozygous (SC, SBetaThal, SE) and 87 normal (AA) and/or sickle cell trait (AS) sickle cell cases. We observed a significant difference in the height/age ratio (P ¥). Conclusion: The results of our study revealed stunted growth in children with sickle cell disease.

关键词： Sickle Cell Disease Nutrition Growth Puberty Guinea

Congenital Cervico-Mandibular Cystic Lymphangioma in Pediatric Surgical Setting in Guinea

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Open Journal of Pediatrics 2024年第1期14卷 164-173页

作者： Thierno Saïdou Barry mohamed Lamine Sadou Sacko Balla Keita Aissatou Bailo Balde Mamadou Alpha Diallo Moussa Conde Ibrahima Kalil Dioubate Mory Sangare Salamata Sall Mariama Dalanda Diallo Daniel Agbo-Panzo Pediatric Surgery Department Donka National Hospital (HND) of Conakry University Hospital (Gamal Abdel Nasser University of Conakry (UGANC) of Guinea) Conakry Guinea Hadja Bilguissou BARRY Medical-Surgical Clinic (HBB) Conakry Guinea Albert Royer Children’s Service Cheikh Anta DIOP University (UCAD) Dakar Senegal Surgery Department of the Regional Hospital Center of Ziguinchor (CHRZ) Ziguinchor Senegal

Introduction: Cystic lymphangiomas are rare benign malformative tumors of the lymphatic system of obscure etiopathogenesis. The cervico-facial location remains the most common (75%). Although benign, these tumors remain potentially fatal, due to possible compression of the upper aero-digestive tract. The aim of this work is to study the epidemiological, diagnostic and therapeutic characteristics of cervico-mandibular congenital cystic lymphangiomas in the pediatric surgery department of the Donka National Hospital (HND) Conakry. Patients and methods: This is a retrospective and descriptive study of 13 files lasting 7 years from January 2015 to December 31, 2021. The files of children whose age is less than or equal to 15 years operated on cervical tumor with histological evidence of cystic lymphangioma were retained. The data were analyzed using SPSS statistical software 21 and anonymously. Results: The incidence of this study was 1.86 cases per year and a sex ratio of 0.62 in favor of girls. The average age was 8 months 19 days. In the antecedents, we only find poorly monitored pregnancies. The average size of the tumors was 11.85 cm. Cervical ultrasound and standard x-ray of the cervical mass were the only examinations performed. Total surgical excision of the cervical tumor was performed in all patients. The mass was polycystic on exploration. The histological examination of the surgical specimens was in favor of a cystic lymphangioma. The surgical consequences were simple in 11 patients (84.62%) and complicated by parietal suppuration in 2 cases (15.38%). There were no cases of recurrence after one year of follow-up. Conclusion: Cervico-mandibular cystic lymphangiomas are the most frequent locations of congenital lymphangiomas in children. Their severity is linked to the risk of compression of the aero-digestive tracts. Their diagnosis must be confirmed by the histology of the surgical specimen. Despite the therapeutic arsenal, excision of the cystic mass remain

关键词： Congenital Cystic Lymphangioma (LKC) Child Pediatric Surgery Guinea