期刊文献+
共找到220篇文章
< 1 2 11 >
每页显示 20 50 100
An efficient enhanced k-means clustering algorithm 被引量:30
1
作者 FAHIM A.M SALEM A.M +1 位作者 TORKEY F.A ramadan M.A 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第10期1626-1633,共8页
In k-means clustering, we are given a set of n data points in d-dimensional space R^d and an integer k and the problem is to determine a set of k points in R^d, called centers, so as to minimize the mean squared dista... In k-means clustering, we are given a set of n data points in d-dimensional space R^d and an integer k and the problem is to determine a set of k points in R^d, called centers, so as to minimize the mean squared distance from each data point to its nearest center. In this paper, we present a simple and efficient clustering algorithm based on the k-means algorithm, which we call enhanced k-means algorithm. This algorithm is easy to implement, requiring a simple data structure to keep some information in each iteration to be used in the next iteration. Our experimental results demonstrated that our scheme can improve the computational speed of the k-means algorithm by the magnitude in the total number of distance calculations and the overall time of computation. 展开更多
关键词 Clustering algorithms Cluster analysis k-means algorithm Data analysis
下载PDF
氧化应激检测在男性不育临床中的应用 被引量:26
2
作者 Ashok Agarwal ramadan Abdou Saleh 《中华男科学杂志》 CAS CSCD 2002年第1期1-9,共9页
活性氧 (ROS)在低浓度发生可以调节正常精子功能 ,而高浓度ROS危害精子的存活力和功能。ROS产生过量与抗氧化系统损伤会发生氧化应激 (OS)。目前认为损伤OS促进了一系列男性生殖功能的病理学改变。ROS介导的精子质膜过氧化损伤 ,可以解... 活性氧 (ROS)在低浓度发生可以调节正常精子功能 ,而高浓度ROS危害精子的存活力和功能。ROS产生过量与抗氧化系统损伤会发生氧化应激 (OS)。目前认为损伤OS促进了一系列男性生殖功能的病理学改变。ROS介导的精子质膜过氧化损伤 ,可以解释在高比例的不育病人中观察到的精子功能缺陷。ROS产生过多也会破坏精子核内DNA的完整性。DNA碱基对OS敏感 ,这些结构的过氧化能引起碱基修饰、DNA链断裂以及染色质交联。由过量ROS诱发的DNA损伤会加速生殖细胞凋亡过程 ,导致与男性不育相关的精子计数降低 ,以及可以解释近半个世纪以来所观察到的精液质量明显下降现象。近 10年来 ,克里夫兰临床基金会的研究组已经查明了男性不育中OS的关键作用 ;研究的主要目的是将这些重要的知识从实验室转向临床应用。我们设计的研究目标 :①理解精液中OS发生的精确机制 ;②建立准确评估OS状态的实验 ,并进行质控研究 ;③检测OS与精子核DNA损伤之间的相关性 ; 展开更多
关键词 活性氧 氧化应激 DNA损伤 男性不育
下载PDF
Rubber band ligation for 750 cases of symptomatic hemorrhoids out of 2200 cases 被引量:23
3
作者 Ayman M El Nakeeb Amir A Fikry +11 位作者 Waleed H Omar Elyamani M Fouda Tito A El Metwally Hosam E Ghazy Sabry A Badr Mohmed Y Abu Elkhar Salih M Elawady Hisham H Abd Elmoniam Waiel W Khafagy Mosaad M Morshed ramadan E El Lithy Mohamed E Farid 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第42期6525-6530,共6页
AIM: To study the results for the treatment of symptomatic hemorrhoids using rubber band ligation (RBL) method. METHODS: A retrospective study for 750 patients who came to the colorectal unit from June, 1998 to Septem... AIM: To study the results for the treatment of symptomatic hemorrhoids using rubber band ligation (RBL) method. METHODS: A retrospective study for 750 patients who came to the colorectal unit from June, 1998 to September, 2006, data was retrieved from archived fi les. RBL was performed using the Mc Gown applicator on an outpatient basis. The patients were asked to return to out-patient clinic for follow up at 2 wk, 1 mo, 6 mo and through telephone call every 6 mo for 2 years). RESULTS: After RBL, 696 patients (92.8%) were cured with no difference in outcome for second or third degree hemorrhoids (P = 0.31). Symptomatic recurrence was detected in 11.04% after 2 years. A total of 52 patients (6.93%) had 77 complications from RBL which required no hospitalization. Complications were pain, rectal bleeding and vaso-vagal symptoms(4.13%, 4.13% and 1.33% of patients, respectively). At 1 mo there were a significant improvement in mean SF-36 scores over baseline in five items, while after 2 years there were improvement in all items over baseline, but not significant. No significant manometeric changes after band ligation. CONCLUSION: RBL is a simple, safe and effective method for treating symptomatic second and third degree hemorrhoids as an out patient procedure with signifi cant improvement in quality of life. RBL doesn't alter ano-rectal functions. 展开更多
关键词 PILES Rectal bleeding Barron banding HEMORRHOIDECTOMY
下载PDF
Premature ejaculation:an update on definition and pathophysiology 被引量:18
4
作者 Mohammed Abu El-Hamd ramadan Saleh Ahmad Majzoub 《Asian Journal of Andrology》 SCIE CAS CSCD 2019年第5期425-432,共8页
Premature ejaculation(PE)is the most comm on male sexual dysfunction,which represents a diag no stic as well as a therapeutic challenge for physicians.However,no universally accepted definition is currently available ... Premature ejaculation(PE)is the most comm on male sexual dysfunction,which represents a diag no stic as well as a therapeutic challenge for physicians.However,no universally accepted definition is currently available for PE.As a result,physicians continue to diagnose patients with PE according to major guidelines set by the professional societies.These guidelines either recommend the use of validated questionnaires or patient-reported outcomes.Recent efforts directed toward classifying PE may help provide a better understanding of the prevalence and risk factors of this disorder.While the exact etiology of PE has not been clearly elucidated,several risk factors have been strongly reported in the literature.Clearly,to understand the revised definition of PE,its etiology and pathophysiology is necessary to improve the clinical management of this medical condition and form the basis of future research in this regard.In this review,we highlight the past and current definitions of PE and present an appraisal on the classifications and theories suggested for the etiopathogenesis of PE. 展开更多
关键词 ejaculatory DISORDERS MALE sexual DYSFUNCTION PREMATURE EJACULATION
原文传递
Effect of cold deformation and heat treatment on microstructure and mechanical properties of TC21 Ti alloy 被引量:14
5
作者 ramadan N.ELSHAER Khaled M.IBRAHIM 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第5期1290-1299,共10页
In the present research work on TC21 titanium alloy(6.5 Al-3 Mo-1.9 Nb-2.2 Sn-2.2 Zr-1.5 Cr), the effects of cold deformation, solution treatment with different cooling rates and then aging on microstructure, hardness... In the present research work on TC21 titanium alloy(6.5 Al-3 Mo-1.9 Nb-2.2 Sn-2.2 Zr-1.5 Cr), the effects of cold deformation, solution treatment with different cooling rates and then aging on microstructure, hardness and wear property were investigated. A cold deformation at room temperature with 15% reduction in height was applied on annealed samples. The samples were solution-treated at 920 ℃ for 15 min followed by different cooling rates of water quenching(WQ), air cooling(AC) and furnace cooling(FC) to room temperature. Finally, the samples were aged at 590 ℃ for 4 h. Secondary α-platelets precipitated in residual β-phase in the case of solution-treated samples with AC condition and aged ones. The maximum hardness of HV 470 was obtained for WQ + aging condition due to the presence of high amount of residual β-matrix(69%), while the minimum hardness of HV 328 was reported for FC condition. Aging process after solution treatment can considerably enhance the wear property and this enhancement can reach up to about 122% by applying aging after WQ compared with the annealed samples. 展开更多
关键词 TC21 titanium alloy DEFORMATION heat treatment cooling rate microstructure mechanical properties WEAR
下载PDF
Age distribution,polyps and rectal cancer in the Egyptian population-based cancer registry 被引量:14
6
作者 Darlene Veruttipong Amr S Soliman +5 位作者 Samuel F Gilbert Taylor S Blachley Ahmed Hablas Mohamed ramadan Laura S Rozek Ibrahim A Seifeldin 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第30期3997-4003,共7页
AIM:To describe the clinical and epidemiologic profiles of the disease and to compare the findings with those generated from the previous hospital-based studies.METHODS:The Gharbiah cancer registry is the only populat... AIM:To describe the clinical and epidemiologic profiles of the disease and to compare the findings with those generated from the previous hospital-based studies.METHODS:The Gharbiah cancer registry is the only population-based cancer registry in Egypt since 1998.We analyzed the data of all colorectal cancer patients included in the registry for the period of 1999-2007.All medical records of the 1364 patients diagnosed in Gharbiah during the study period were retrieved and the following information abstracted:age,residence,diagnosis date,grade,stage,topology,clinical characteristics,and histology variables.Egyptian census data for 1996 and 2006 were used to provide the general population's statistics on age,sex,residence and other related demographic factors.In addition to age-and sex-specific incidence rate analyses,we analyze the data to explore the incidence distribution by rural-urban differences among the 8 districts of the province.We also compared the incidence rates of Gharbiah to the rates of the Surveillance Epidemiology and End Results(SEER) data of the United States.RESULTS:Over the 9 year-period,1364 colorectal cancer cases were included.The disease incidence under age 40 years was relatively high(1.3/10 5) while the incidence in the age groups 40 and over was very low(12.0/10 5,19.4/10 5 and 21.2/10 5 in the age groups 40-59 years,60-69 years and > 70 years,respectively).The vast majority of tumors(97.2%) had no polyps and 37.2% of the patients presented with primary lesions in the rectum.Colorectal cancer was more common in patients from urban(55%) than rural(45%) areas.Regional differences in colon and rectal cancer incidence in the 8 districts of the study province may reflect different etiologic patterns in this population.The registry data of Egypt shows a slightly higher incidence of colorectal cancer than the United States in subjects under age 40 years.The results also shows significantly lower incidence of colorectal cancer in subjects over age 40 years compared to the same age group in the 展开更多
关键词 Colorectal cancer Young-onset Polyps Developing countries Egypt
下载PDF
Microalgae-based wastewater treatment:Mechanisms,challenges,recent advances,and future prospects 被引量:7
7
作者 Abdallah Abdelfattah Sameh Samir Ali +9 位作者 Hassan ramadan Eslam Ibrahim El-Aswar Reham Eltawab Shih-Hsin Ho Tamer Elsamahy Shengnan Li Mostafa M.El-Sheekh Michael Schagerl Michael Kornaros Jianzhong Sun 《Environmental Science and Ecotechnology》 SCIE 2023年第1期5-22,共18页
The rapid expansion of both the global economy and the human population has led to a shortage of water resources suitable for direct human consumption.As a result,water remediation will inexorably become the primary f... The rapid expansion of both the global economy and the human population has led to a shortage of water resources suitable for direct human consumption.As a result,water remediation will inexorably become the primary focus on a global scale.Microalgae can be grown in various types of wastewaters(WW).They have a high potential to remove contaminants from the effluents of industries and urban areas.This review focuses on recent advances on WW remediation through microalgae cultivation.Attention has already been paid to microalgae-based wastewater treatment(WWT)due to its low energy requirements,the strong ability of microalgae to thrive under diverse environmental conditions,and the potential to transform WW nutrients into high-value compounds.It turned out that microalgae-based WWT is an economical and sustainable solution.Moreover,different types of toxins are removed by microalgae through biosorption,bioaccumulation,and biodegradation processes.Examples are toxins from agricultural runoffs and textile and pharmaceutical industrial effluents.Microalgae have the potential to mitigate carbon dioxide and make use of the micronutrients that are present in the effluents.This review paper highlights the application of microalgae in WW remediation and the remediation of diverse types of pollutants commonly present in WW through different mechanisms,simultaneous resource recovery,and efficient microalgae-based co-culturing systems along with bottlenecks and prospects. 展开更多
关键词 BIOREMEDIATION Wastewater treatment Environmental applications MICROALGAE Co-culturing
原文传递
Solid phase microextraction chemical biopsy tool for monitoring of doxorubicin residue during in vivo lung chemo-perfusion 被引量:7
8
作者 Barbara Bojko Nikita Looby +11 位作者 Mariola Olkowicz Anna Roszkowska Bogumiła Kupcewicz Pedro Reck dos Santos Khaled ramadan Shaf Keshavjee Thomas K.Waddell German Goomez-Rios Marcos Tascon Krzysztof Gorynski Marcelo Cypel Janusz Pawliszyn 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2021年第1期37-47,共11页
Development of a novel in vivo lung perfusion(IVLP)procedure allows localized delivery of high-dose doxorubicin(DOX)for targeting residual micrometastatic disease in the lungs.However,DOX delivery via IVLP requires ca... Development of a novel in vivo lung perfusion(IVLP)procedure allows localized delivery of high-dose doxorubicin(DOX)for targeting residual micrometastatic disease in the lungs.However,DOX delivery via IVLP requires careful monitoring of drug level to ensure tissue concentrations of this agent remain in the therapeutic window.A small dimension nitinol wire coated with a sorbent of biocompatible morphology(Bio-SPME)has been clinically evaluated for in vivo lung tissue extraction and determination of DOX and its key metabolites.The in vivo Bio-SPME-IVLP experiments were performed on pig model over various(150 and 225 mg/m^(2))drug doses,and during human clinical trial.Two patients with metastatic osteosarcoma were treated with a single 5 and 7 μg/mL(respectively)dose of DOX during a 3-h IVLP.In both pig and human cases,DOX tissue levels presented similar trends during IVLP.Human lung tissue concentrations of drug ranged between 15 and 293 μg/g over the course of the IVLP procedure.In addition to DOX levels,Bio-SPME followed by liquid chromatography-mass spectrometry analysis generated 64 metabolic features during endogenous metabolite screening,providing information about lung status during drug administration.Real-time monitoring of DOX levels in the lungs can be performed effectively throughout the IVLP procedure by in vivo Bio-SPME chemical biopsy approach.Bio-SPME also extracted various endogenous molecules,thus providing a real-time snapshot of the physiology of the cells,which might assist in the tailoring of personalized treatment strategy. 展开更多
关键词 In vivo solid phase microextraction Metabolite profiling Spatial resolution Therapeutic drug monitoring Tissue analysis
下载PDF
开式热源塔技术研究现状及发展趋势
9
作者 李雷 张化福 +3 位作者 张振涛 杨俊玲 章学来 ramadan Abdelhamed EIGAMAL 《热力发电》 CAS CSCD 北大核心 2024年第11期66-78,共13页
介绍了开式热源塔的2种基本结构、工作原理及塔内气液热质交换对热源塔技术,系统总结了开式热源塔的结构组件、防冻液、传热传质特性和适用性研究现状,重点阐述开式热源塔在防冻液开发和传热传质过程的研究热点及主要进展。虽然开式热... 介绍了开式热源塔的2种基本结构、工作原理及塔内气液热质交换对热源塔技术,系统总结了开式热源塔的结构组件、防冻液、传热传质特性和适用性研究现状,重点阐述开式热源塔在防冻液开发和传热传质过程的研究热点及主要进展。虽然开式热源塔技术仍存在防冻液不够安全环保,具有腐蚀性和毒性且再生技术不够稳定,能耗过高等缺点,但开式热源塔换热强度大、采热效率高、结构简单维护成本低,在建筑供暖领域具有广阔的应用前景,未来开式热源塔技术将朝着更高效稳定、更安全环保、更节能低碳的方向发展,构建更佳绿色低碳的供热体系。 展开更多
关键词 能源塔 开式热源塔 低温采热 传热传质 防冻液
下载PDF
A Proposed Approach for Measuring Maturity Level of Software Delivery
10
作者 Osama Hassan Mansour Atef Raslan Nagy ramadan 《Journal of Software Engineering and Applications》 2024年第5期228-245,共18页
Software delivery is vital for modern organizations, driving innovation and competitiveness. Measuring an organization’s maturity in software delivery is crucial for efficiency and quality. The Capability Maturity Mo... Software delivery is vital for modern organizations, driving innovation and competitiveness. Measuring an organization’s maturity in software delivery is crucial for efficiency and quality. The Capability Maturity Model (CMM) framework provides a roadmap for improvement but assessing an organization’s CMM Level is challenging. This paper offers a quantitative approach tailored to the CMM framework, using Goal-Question-Metric (GQM) frame-works for each key process area (KPA). These frameworks include metrics and questions to compute maturity scores effectively. The study also refines practices into questions for a thorough assessment. The result is an Analysis Matrix that calculates weighted scores and an overall maturity score. This approach helps organizations assess and enhance their software delivery processes systematically, aiming for improved practices and growth. 展开更多
关键词 CMM CMMI Software Delivery MATURITY KPAs GQM PRACTICES
下载PDF
Percutaneous Fixation as an Option for Traumatic Neurologically Intact Thoracolumbar Vertebral Fractures
11
作者 Ahmed Hosameldin Ashraf Osman +1 位作者 Mahmoud Gomaa Mahmoud ramadan 《Open Journal of Modern Neurosurgery》 2024年第4期246-255,共10页
Background: The most frequent spinal fracture is the thoracolumbar fracture. Minimally invasive percutaneous fixation of cases having thoracolumbar vertebral fractures without neurological impairments has remained con... Background: The most frequent spinal fracture is the thoracolumbar fracture. Minimally invasive percutaneous fixation of cases having thoracolumbar vertebral fractures without neurological impairments has remained controversial. The advantages of minimally invasive percutaneous fixation are decreasing muscle and soft tissue injury, decreasing blood loss and infection rate, in addition to shortening hospital stay and recovery times. In comparison to the open technique, percutaneous fixation is adequate for treating thoracolumbar (TL) fractures without causing neurological impairments & with satisfactory outcomes in terms of kyphosis decline. Elevated radiation exposure to the surgeon &the patient, lack of decompression and fusion via bone graft, & a steep learning curve are all disadvantages of percutaneous fixation of vertebral fractures. Methods: This study was retrospectively conducted on forty-eight patients, age ranging from 16 to 65 years old, with a thoracolumbar (TL) fracture without causing neurological impairments who were meeting the eligibility criteria for fixation in the period from July 2019 to January 2024. Results: We included the forty-eight patients who met the inclusion criteria (34 males and 14 females) their ages ranged from 16 to 65 years. The most common pathology was L1 fracture in 38 patients. No major complications were experienced, only wound infection in five patients which was treated efficiently with repeated dressings and broad-spectrum antibiotics. Four patients experienced misdirected screws, only in one patient the screw encroach into the spinal canal with no deficit experienced, while the other three showed minimally laterally deviated screws. Conclusion: The advantages of percutaneous pedicle screw fixation in thoracolumbar fractures through preservation of posterior musculature, are less blood loss, shorter operative time, lower infection risk, less post-operative pain, shorter rehabilitation time as well as a shorter hospital stay. Limitations of percutaneous fixation include 展开更多
关键词 Thoracolumbar Fractures Fracture Stability Percutaneous Fixation
下载PDF
Gut virome:New key players in the pathogenesis of inflammatory bowel disease
12
作者 Helal F Hetta Rehab Ahmed +4 位作者 Yasmin N ramadan Hayam Fathy Mohammed Khorshid Mohamed M Mabrouk Mai Hashem 《World Journal of Methodology》 2025年第2期27-43,共17页
Inflammatory bowel disease(IBD)is a chronic inflammatory illness of the intes-tine.While the mechanism underlying the pathogenesis of IBD is not fully under-stood,it is believed that a complex combination of host immu... Inflammatory bowel disease(IBD)is a chronic inflammatory illness of the intes-tine.While the mechanism underlying the pathogenesis of IBD is not fully under-stood,it is believed that a complex combination of host immunological response,environmental exposure,particularly the gut microbiota,and genetic suscept-ibility represents the major determinants.The gut virome is a group of viruses found in great frequency in the gastrointestinal tract of humans.The gut virome varies greatly among individuals and is influenced by factors including lifestyle,diet,health and disease conditions,geography,and urbanization.The majority of research has focused on the significance of gut bacteria in the progression of IBD,although viral populations represent an important component of the microbiome.We conducted this review to highlight the viral communities in the gut and their expected roles in the etiopathogenesis of IBD regarding published research to date. 展开更多
关键词 Inflammatory bowel disease PATHOGENESIS Gut virome BACTERIOPHAGE Eukaryotic viruses
Plasma D-dimer level in early and late-onset neonatal sepsis 被引量:6
13
作者 Mohammed Al-Biltagi Ehab M Hantash +3 位作者 Mohammed ramadan El-Shanshory Enayat Aly Badr Mohamed Zahra Manar Hany Anwar 《World Journal of Critical Care Medicine》 2022年第3期139-148,共10页
BACKGROUND Neonatal sepsis is a life-threatening disease.Early diagnosis is essential,but no single marker of infection has been identified.Sepsis activates a coagulation cascade with simultaneous production of the D-... BACKGROUND Neonatal sepsis is a life-threatening disease.Early diagnosis is essential,but no single marker of infection has been identified.Sepsis activates a coagulation cascade with simultaneous production of the D-dimers due to lysis of fibrin.Ddimer test reflects the activation of the coagulation system.AIM To assess the D-dimer plasma level,elaborating its clinicopathological value in neonates with early-onset and late-onset neonatal sepsis.METHODS The study was a prospective cross-sectional study that included ninety neonates;divided into three groups:Group I:Early-onset sepsis(EOS);Group II:Late-onset sepsis(LOS);and GroupⅢ:Control group.We diagnosed neonatal sepsis according to our protocol.C-reactive protein(CRP)and D-dimer assays were compared between EOS and LOS and correlated to the causative microbiological agents.RESULTS D-dimer was significantly higher in septic groups with a considerably higher number of cases with positive D-dimer.Neonates with LOS had substantially higher levels of D-dimer than EOS,with no significant differences in CRP.Neonates with LOS had a significantly longer hospitalization duration and higher gram-negative bacteriemia and mortality rates than EOS(P<0.01).Gramnegative bacteria have the highest D-dimer levels(Acinetobacter,Klebsiella,and Pseudomonas)and CRP(Serratia,Klebsiella,and Pseudomonas);while gram-positive sepsis was associated with relatively lower levels.D-dimer had a significant negative correlation with hemoglobin level and platelet count;and a significant positive correlation with CRP,hospitalization duration,and mortality rates.The best-suggested cut-off point for D-dimer in neonatal sepsis was 0.75 mg/L,giving a sensitivity of 72.7%and specificity of 86.7%.The D-dimer assay has specificity and sensitivity comparable to CRP in the current study.CONCLUSION The current study revealed a significant diagnostic value for D-dimer in neonatal sepsis.D-dimer can be used as an adjunct to other sepsis markers to increase the sensitivity and specificity of diagnosing ne 展开更多
关键词 Early-onset neonatal sepsis Late-onset neonatal sepsis C-reactive protein D-DIMER
下载PDF
A survey of recent interactive image segmentation methods 被引量:6
14
作者 Hiba ramadan Chaymae Lachqar Hamid Tairi 《Computational Visual Media》 EI CSCD 2020年第4期355-384,共30页
Image segmentation is one of the most basic tasks in computer vision and remains an initial step of many applications. In this paper, we focus on interactive image segmentation(IIS), often referred to as foreground–b... Image segmentation is one of the most basic tasks in computer vision and remains an initial step of many applications. In this paper, we focus on interactive image segmentation(IIS), often referred to as foreground–background separation or object extraction, guided by user interaction. We provide an overview of the IIS literature by covering more than 150 publications, especially recent works that have not been surveyed before. Moreover, we try to give a comprehensive classification of them according to different viewpoints and present a general and concise comparison of the most recent published works. Furthermore, we survey widely used datasets,evaluation metrics, and available resources in the field of IIS. 展开更多
关键词 interactive image segmentation user interaction label propagation deep learning superpixels
原文传递
11B NMR Spectroscopy of Lead Borate Glasses: Additive Effect of Cerium Oxide 被引量:3
15
作者 Gomaa El-Damrawi Fawzia Gharghar +1 位作者 Rawia ramadan Mohamed Aboelez 《New Journal of Glass and Ceramics》 2016年第4期57-63,共7页
Glasses and glass ceramics in the system xCeO<sub>2·</sub>(50 - x)PbO·50B<sub>2</sub>O<sub>3</sub> (0 ≤ x ≤ 50) have been studied, for the first time, by NMR a... Glasses and glass ceramics in the system xCeO<sub>2·</sub>(50 - x)PbO·50B<sub>2</sub>O<sub>3</sub> (0 ≤ x ≤ 50) have been studied, for the first time, by NMR and FTIR techniques. Effect of CeO<sub>2</sub> substitution with PbO on NMR parameters has been discussed in terms of changing both boron and cerium coordination. The quantitative fraction of four coordinated boron (N<sub>4</sub>) has been simply determined from <sup>11</sup>B NMR spectroscopy. On the other hand, the fraction of total tetrahedral structural units B<sub>4</sub> (BO<sub>4</sub> + PbO<sub>4</sub> + CeO<sub>4</sub>) is obtained from FTIR spectral analysis. It is not possible to get the fraction of cerium oxide directly from the applied spectroscopic tools. Therefore, a simple approach is applied, for the first time, to determine CeO<sub>4</sub> fraction by using the different criteria of both <sup>11</sup>B NMR and FTIR spectroscopy. The fraction of B<sub>4</sub> species is equal to N<sub>4</sub>, within the experimental error, of the same glasses in the composition region of up to 10 mol% CeO<sub>2</sub>. On the other hand, there is a clear difference between both N<sub>4</sub> and B<sub>4</sub> values in glasses of higher CeO<sub>2 </sub>content (>10 mol%). The related difference showed a linear increasing trend with increasing the content of CeO<sub>2</sub> in the glass. This was discussed on the bases of structural role of CeO<sub>2</sub> which acts as a glass former in the region >10 mol%, while, at lower concentration, it consumed as a glass modifier. 展开更多
关键词 New Approach Cerium Oxide Boron Fraction
下载PDF
Impact of the source and serial passaging of goat mesenchymal stem cells on osteogenic differentiation potential:implications for bone tissue engineering 被引量:5
16
作者 Hoda Elkhenany Lisa Amelse +2 位作者 Marc Caldwell ramadan Abdelwahed Madhu Dhar 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2016年第4期482-494,共13页
Background: Adult mesenchymal stem cells (MSCs) can be conveniently sampled from bone marrow, peripheral blood, muscle, adipose and connective tissue, harvested from various species, including, rodents, dogs, cats,... Background: Adult mesenchymal stem cells (MSCs) can be conveniently sampled from bone marrow, peripheral blood, muscle, adipose and connective tissue, harvested from various species, including, rodents, dogs, cats, horses, sheep, goats and human beings. The MSCs isolated from adult tissues vary in their morphological and functional properties. These variations are further complicated when cells are expanded by passaging in culture. These differences and changes in MSCs must be considered prior to their application in the clinic or in a basic research study. Goats are commonly used as animal models for bone tissue engineering to test the potential of stem cells for bone regeneration. As a result, goat MSCs isolated from bone marrow or adipose tissue should be evaluated using in vitro assays, prior to their application in a tissue engineering project. Results: In this study, we compared the stem cell properties of MSCs isolated from goat bone marrow and adipose tissue. We used quantitative and qualitative assays with a focus on osteogenesis, including, colony forming unit, rate of cell proliferation, tri-lineage differentiation and expression profiling of key signal transduction proteins to compare MSCs from low and high passages. Primary cultures generated from each source displayed the stem cell characteristics, with variations in their osteogenic potentials. Most importantly, low passaged bone marrow MSCs displayed a significantly higher and superior osteogenic potential, and hence, will be the preferred choice for bone tissue engineering in future in vivo experiments. In the bone marrow MSCs, this process is potentially mediated by the p38 MAPK pathway. On the other hand, osteogenic differentiation in the adipose tissue MSCs may involve the p44/42 MAPK pathway. Conclusions: Based on these data, we can conclude that bone marrow and fat-derived MSCs undergo osteogenesis via two distinct signaling pathways. Even though the bone marrow MSCs are the preferred source for bone tissue engineering, the adipose 展开更多
关键词 Caprine mesenchymal Osteogenesis stem cells
下载PDF
Infectious causes of fever of unknown origin in developing countries: An international ID-IRI study 被引量:1
17
作者 Hakan Erdem Jaffar AAl-Tawfiq +20 位作者 Maha Abid Wissal Ben Yahia George Akafity Manar Ezzelarab ramadan Fatma Amer Amani El-Kholy Atousa Hakamifard Bilal Ahmad Rahimi Farouq Dayyab Hulya Caskurlu Reham Khedr Muhammad Tahir Lysien Zambrano Mumtaz Ali Khan Aun Raza Nagwa Mostafa El-Sayed Magdalena Baymakova Aysun Yalci Yasemin Cag Umran Elbahr Aamer Ikram 《Journal of Intensive Medicine》 CSCD 2024年第1期94-100,共7页
Background:Fever of unknown origin(FUO)in developing countries is an important dilemma and further research is needed to elucidate the infectious causes of FUO.Methods:A multi-center study for infectious causes of FUO... Background:Fever of unknown origin(FUO)in developing countries is an important dilemma and further research is needed to elucidate the infectious causes of FUO.Methods:A multi-center study for infectious causes of FUO in lower middle-income countries(LMIC)and lowincome countries(LIC)was conducted between January 1,2018 and January 1,2023.In total,15 participating centers from seven different countries provided the data,which were collected through the Infectious DiseasesInternational Research Initiative platform.Only adult patients with confirmed infection as the cause of FUO were included in the study.The severity parameters were quick Sequential Organ Failure Assessment(qSOFA)≥2,intensive care unit(ICU)admission,vasopressor use,and invasive mechanical ventilation(IMV).Results:A total of 160 patients with infectious FUO were included in the study.Overall,148(92.5%)patients had community-acquired infections and 12(7.5%)had hospital-acquired infections.The most common infectious syndromes were tuberculosis(TB)(n=27,16.9%),infective endocarditis(n=25,15.6%),malaria(n=21,13.1%),brucellosis(n=15,9.4%),and typhoid fever(n=9,5.6%).Plasmodium falciparum,Mycobacterium tuberculosis,Brucellae,Staphylococcus aureus,Salmonella typhi,and Rickettsiae were the leading infectious agents in this study.A total of 56(35.0%)cases had invasive procedures for diagnosis.The mean qSOFA score was 0.76±0.94{median(interquartile range[IQR]):0(0–1)}.ICU admission(n=26,16.2%),vasopressor use(n=14,8.8%),and IMV(n=10,6.3%)were not rare.Overall,38(23.8%)patients had at least one of the severity parameters.The mortality rate was 15(9.4%),and the mortality was attributable to the infection causing FUO in 12(7.5%)patients.Conclusions:In LMIC and LIC,tuberculosis and cardiac infections were the most severe and the leading infections causing FUO. 展开更多
关键词 Developing countries Fever of unknown origin INFECTION
原文传递
ANFIS-based Sensor Fusion System of Sit-to-stand for Elderly People Assistive Device Protocols 被引量:5
18
作者 Omar Salah Ahmed A.ramadan +3 位作者 Salvatore Sessa Ahmed Abo Ismail Makasatsu Fujie Atsuo Takanishi 《International Journal of Automation and computing》 EI CSCD 2013年第5期405-413,共9页
This paper describes the analysis and design of an assistive device for elderly people under development at the EgyptJapan University of Science and Technology(E-JUST) named E-JUST assistive device(EJAD).Several e... This paper describes the analysis and design of an assistive device for elderly people under development at the EgyptJapan University of Science and Technology(E-JUST) named E-JUST assistive device(EJAD).Several experiments were carried out using a motion capture system(VICON) and inertial sensors to identify the human posture during the sit-to-stand motion.The EJAD uses only two inertial measurement units(IMUs) fused through an adaptive neuro-fuzzy inference systems(ANFIS) algorithm to imitate the real motion of the caregiver.The EJAD consists of two main parts,a robot arm and an active walker.The robot arm is a 2-degree-of-freedom(2-DOF) planar manipulator.In addition,a back support with a passive joint is used to support the patient s back.The IMUs on the leg and trunk of the patient are used to compensate for and adapt to the EJAD system motion depending on the obtained patient posture.The ANFIS algorithm is used to train the fuzzy system that converts the IMUs signals to the right posture of the patient.A control scheme is proposed to control the system motion based on practical measurements taken from the experiments.A computer simulation showed a relatively good performance of the EJAD in assisting the patient. 展开更多
关键词 Adaptive neuro-fuzzy inference systems(ANFIS) sensor fusion assistive technologies sit-to-stand motion analysis inertial measurement units
原文传递
MXene@c-MWCNT Adhesive Silica Nanofiber Membranes Enhancing Electromagnetic Interference Shielding and Thermal Insulation Performance in Extreme Environments 被引量:1
19
作者 Ziyuan Han Yutao Niu +11 位作者 Xuetao Shi Duo Pan Hu Liu Hua Qiu Weihua Chen Ben Bin Xu Zeinhom MEl-Bahy Hua Hou Eman ramadan Elsharkawy Mohammed AAmin Chuntai Liu Zhanhu Guo 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第10期82-98,共17页
A lightweight flexible thermally stable composite is fabricated by com-bining silica nanofiber membranes(SNM)with MXene@c-MWCNT hybrid film.The flexible SNM with outstanding thermal insulation are prepared from tetrae... A lightweight flexible thermally stable composite is fabricated by com-bining silica nanofiber membranes(SNM)with MXene@c-MWCNT hybrid film.The flexible SNM with outstanding thermal insulation are prepared from tetraethyl orthosilicate hydrolysis and condensation by electrospinning and high-temperature calcination;the MXene@c-MWCNT_(x:y)films are prepared by vacuum filtration tech-nology.In particular,the SNM and MXene@c-MWCNT_(6:4)as one unit layer(SMC_(1))are bonded together with 5 wt%polyvinyl alcohol(PVA)solution,which exhibits low thermal conductivity(0.066 W m^(-1)K^(-1))and good electromagnetic interference(EMI)shielding performance(average EMI SE_(T),37.8 dB).With the increase in func-tional unit layer,the overall thermal insulation performance of the whole composite film(SMC_(x))remains stable,and EMI shielding performance is greatly improved,especially for SMC_(3)with three unit layers,the average EMI SET is as high as 55.4 dB.In addition,the organic combination of rigid SNM and tough MXene@c-MWCNT_(6:4)makes SMC_(x)exhibit good mechanical tensile strength.Importantly,SMC_(x)exhibit stable EMI shielding and excellent thermal insulation even in extreme heat and cold environment.Therefore,this work provides a novel design idea and important reference value for EMI shielding and thermal insulation components used in extreme environmental protection equipment in the future. 展开更多
关键词 SiO_(2)nanofiber membranes MXene@c-MWCNT Composite film Thermal insulation Electromagnetic interference shielding
下载PDF
Nuclear Magnetic Resonance and FTIR Structural Studies on Borosilicate Glasses Containing Iron Oxide 被引量:2
20
作者 Gomaa El-Damrawi Abdel Meguid Hassan +1 位作者 Rawia ramadan Sammer El-Jadal 《New Journal of Glass and Ceramics》 2016年第4期47-56,共10页
The structure of borosilicate glasses of composition 30Na<sub>2</sub>O-2Al<sub>2</sub>O<sub>3</sub>-25SiO<sub>2</sub>-xFe<sub>2</sub>O<sub>3</sub>... The structure of borosilicate glasses of composition 30Na<sub>2</sub>O-2Al<sub>2</sub>O<sub>3</sub>-25SiO<sub>2</sub>-xFe<sub>2</sub>O<sub>3</sub><sub></sub> (43-x) B<sub>2</sub>O<sub>3</sub> has been investigated in the composition range of 0.5 20 mol% Fe<sub>2</sub>O<sub>3</sub>. <sup>27</sup>Al, <sup>11</sup>B, <sup>29 </sup>Si MAS NMR and FTIR spectroscopies have been used to measure the fraction of different structural species in the glasses. It is evidenced from NMR data that both sodium and Fe<sub>2</sub>O<sub>3</sub> (in low region up to 7 mol%) are the main glass modifier. Structural determination for borosilicate glasses with a high content of (Fe<sub>2</sub>O<sub>3</sub>) was carried out by FTIR spectroscopy, where both <sup>11</sup>B and <sup>29</sup>Si MAS NMR are impossible because of the high quantities of paramagnetic iron (III) species present. NMR analysis was performed on borosilicate glasses containing up to 7 mol% Fe<sub>2</sub>O<sub>3</sub> and the N<sub>4</sub> values obtained by FTIR spectroscopy agree within error with the <sup>11</sup>B NMR results of the same glass samples. Fe<sub>2</sub>O<sub>3</sub> is a main glass modifier in the low-Fe<sub>2</sub>O<sub>3</sub>-content region (≤6 mol%). On other hand, it plays the role of glass former at higher content of Fe<sub>2</sub>O<sub>3</sub>. Increasing both N<sub>4 </sub>of boron tetrahedral units and chemical shift of silicon nuclei to reach maxima at 5 mol% Fe<sub>2</sub>O<sub>3</sub> confirms the role of Fe<sub>2</sub>O<sub>3</sub> as a glass modifier in the low composition region. On the other hand, fast decrease in N<sub>4</sub> with further increasing Fe<sub>2</sub>O<sub>3</sub> contents ≥6 mol%) is an evidence for iron oxide to inter the glass network as a network former. 展开更多
关键词 NMR-FTIR-Spectroscopy-Borosilicate-Glasses
下载PDF
上一页 1 2 11 下一页 到第
使用帮助 返回顶部