RISS 학술연구정보서비스

검색
다국어 입력

http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.

변환된 중국어를 복사하여 사용하시면 됩니다.

예시)
  • 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
  • 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
닫기
    인기검색어 순위 펼치기

    RISS 인기검색어

      검색결과 좁혀 보기

      • 좁혀본 항목

      • 좁혀본 항목 보기순서

        • 원문유무
        • 음성지원유무
          • 원문제공처
          • 등재정보
          • 학술지명
          • 주제분류
          • 발행연도
          • 작성언어
          • 저자

        오늘 본 자료

        • 오늘 본 자료가 없습니다.
        더보기
        • 무료
        • 기관 내 무료
        • 유료
        • Performance Study of Various Routing Protocols in VANET Case of Study

          Mohamed Ben Ahmed,A. A. Boudhir,M. Bouhorma,K. Ben Ahmed 보안공학연구지원센터 2014 International Journal of Future Generation Communi Vol.7 No.6

          Vehicular ad hoc networks or VANET that establishes wireless connections between cars have recently received considerable attention. VANET are used in Intelligent Transportation Systems (ITS) that are designed to offer passengers and vehicles services like warning of accidents, driver assistance, Internet access, etc. The evaluation of VANET routing protocols often involves simulators since management and operation of a large number of real vehicular nodes is expensive. We study the behavior of routing protocols in VANETs by using mobility information obtained from a microscopic vehicular traffic simulator that is based on the real road maps of Tangier in Morocco. In this paper, we evaluate AODV, DSR and OLSR performance in urban scenarios case study. We study those protocols under varying metrics such as node mobility, vehicle density, and with varying traffic rates. We show that clustering effects created by cars aggregating at intersections have remarkable impacts on evaluation and performance metrics. Our objective is to provide a qualitative assessment of the applicability of the protocols in different vehicular scenarios. The results show that OLSR performs best in most of the simulated traffic situations

        • KCI등재

          Performance improvement of hybrid renewable energy sources connected to the grid using artificial neural network and sliding mode control

          Ahmed Elnozahy,Ali M. Yousef,Farag K. Abo‑Elyousr,Moayed Mohamed,Saad A. Mohamed Abdelwahab 전력전자학회 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.8

          The main purpose of this paper to compare and analyze three types of controllers in the three phases DC–AC inverters in hybrid renewable energy source (HRES) systems. To achieve this, two modern controllers are developed and compared based on sliding mode control (SMC) and artificial neural network techniques. The HRESs comprise photovoltaic (PV), wind turbines, battery storage systems, and transmission lines connected to infinite bus bars via a step-up transformer. The developed controllers at the inverter side utilize both voltage control and current regulation. A DC–DC boost converter is employed to set up a voltage demand at the point of common coupling (PCC). Then, the formulation of an HRES with the developed controllers is presented. The developed controllers are considered to operate under various solar radiations, temperatures, and wind speed loading conditions. The HRESs with the developed controllers are simulated via MATLAB/ Simulink to verify the effectiveness of the developed controllers. The obtained results demonstrate that adaptive SMC and artificial ANN control techniques give better results in terms of input power, output power, current, and voltage when compared to classic PI control.

        • SCOPUSKCI등재

          The impact of omeprazole on mycophenolate pharmacokinetics in kidney transplant recipients

          ( Mohamed S. Abdelhalim ),( Ahmed S. Kenawy ),( Heba H. El Demellawy ),( Amany A. Azouz ),( Sarah S. Alghanem ),( Torki Al-otaibi ),( Osama Gheith ),( Mohamed Abd Elmonem ),( Mohammed K. Afifi ),( Rag 대한신장학회 2020 Kidney Research and Clinical Practice Vol.39 No.4

          Background: The absorption rates of mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (ECMPS) may be influenced by the concomitant use of omeprazole. Methods: One hundred kidney transplant patients were recruited during their outpatient visits, including 50 on MMF and 50 on EC-MPS. At the clinic, a predose mycophenolic acid (MPA) sample (C0) was collected; subsequently, the participants received the proton-pump inhibitor omeprazole along with either MMF or EC-MPS. Two more blood samples were collected at 1.5 and 3.5 hours and used to estimate an area under the curve (AUC) from zero to 12 hours [AUC (0-12)]. Results: The mean number of months after transplant was 92 months. The median AUC (0-12) and C0 results were 62.2 mg·h/L and 2.0 mg/L for the MMF group and 71.9 mg·h/L and 1.8 mg/L for the EC-MPS group (P = 0.160 and 0.225, respectively). Interestingly, 54% of the MMF group and 62% of the EC-MPS group showed AUCs above the target values. The correlation between MPA C0 and the predicted AUC was poor in both groups. Conclusion: Omeprazole can be safely co-administered with either MMF or EC-MPS, as it did not compromise the MPA exposure. Unexpectedly, however, a high percentage of patients presented MPA AUCs exceeding the target value, highlighting the importance of periodically assessing MPA level.

        • KCI등재

          Camellia sinesis leaves extract ameliorates high fat diet-induced nonalcoholic steatohepatitis in rats: analysis of potential mechanisms

          Mohamed Safaa H.,Shahat Abdelaaty A.,Mohamed Mohamed Ragaa,Khalil Wagdy K. B.,Salem Ahmed M.,Farrag Abdel Razik H.,Ahmed Hanaa Hamdy 한국약제학회 2021 Journal of Pharmaceutical Investigation Vol.51 No.2

          Purpose Our research aims to address and determine the effect of Camellia sinensis extract in the management of nonalcoholic steatohepatitis (NASH) in rats. Methods Forty adult female albino rats were divided into four groups. Group 1 (G1) served as the control group, while the other three groups received high-fat diet for 32 weeks to induce NASH and then were later assigned to the following groups: (G2) NASH-afflicted group which was left untreated, (G3) NASH-afflicted group treated with Camellia sinensis extract in a dose of 400 mg/kg, and (G4) NASH-afflicted group treated with Camellia sinensis extract in a dose of 200 mg/kg. Results Significant elevation in serum alanine aminotransferase, albumin, bilirubin (total and direct), cholesterol, low density lipoprotein, triglycerides, leptin, Cox-2, and CD40 values was recorded. Moreover, overexpression of hepatic tumor necrosis factor alpha and hepatocyte growth factor genes were recorded, whereas blood platelet count and serum high density lipoprotein concentration revealed significant depletion, which was paralleled by significant downregulation of hepatic adiponectin gene expression level in NASH group versus the control group. On the opposite side, treatment of NASH groups with two different doses of Camellia sinensis extract reversed the values of the measured biochemical parameters and the targeted gene expression levels when compared with the NASH group. Optical micrograph of liver tissue sections of rats treated with Camellia sinensis extract showed the observed improvement in the studied biochemical and genetic markers. Conclusion This study provides a clear evidence for the promising therapeutic potential of Camellia sinensis extract against NASH. This could be ascribed to its hepatoprotective activity, hypolipidemic effect, and anti-inflammatory potency.

        • KCI등재

          Dexmedetomidine during suprazygomatic maxillary nerve block for pediatric cleft palate repair, randomized double-blind controlled study

          Mohamed F. Mostafa,Fatma A. Abdel Aal,Ibrahim Hassan Ali,Ahmed K. Ibrahim,Ragaa Herdan 대한통증학회 2020 The Korean Journal of Pain Vol.33 No.1

          Background: For children with cleft palates, surgeries at a young age are necessary to reduce feeding or phonation difficulties and reduce complications, especially respiratory tract infections and frequent sinusitis. We hypothesized that dexmedetomidine might prolong the postoperative analgesic duration when added to bupivacaine during nerve blocks. Methods: Eighty patients of 1-5 years old were arbitrarily assigned to two equal groups (forty patients each) to receive bilateral suprazygomatic maxillary nerve blocks. Group A received bilateral 0.2 mL/kg bupivacaine (0.125%; maximum volume 4 mL/side). Group B received bilateral 0.2 mL/kg bupivacaine (0.125%) + 0.5 µg/kg dexmedetomidine (maximum volume 4 mL/side). Results: The modified children’s hospital of Eastern Ontario pain scale score was significantly lower in group B children after 8 hours of follow-up postoperatively (P < 0.001). Mean values of heart rate and blood pressure were significantly different between the groups, with lower mean values in group B (P < 0.001). Median time to the first analgesic demand in group A children was 10 hours (range 8-12 hr), and no patients needed analgesia in group B. The sedation score assessment was higher in children given dexmedetomidine (P = 0.03) during the first postoperative 30 minutes. Better parent satisfaction scores (5-point Likert scale) were recorded in group B and without serious adverse effects. Conclusions: Addition of dexmedetomidine 0.5 μg/kg to bupivacaine 0.125% has accentuated the analgesic efficacy of bilateral suprazygomatic maxillary nerve block in children undergoing primary cleft palate repair with less postoperative supplemental analgesia or untoward effects.

        • MicroRNAs and Metastasis-related Gene Expression in Egyptian Breast Cancer Patients

          Hafez, Mohamed M.,Hassan, Zeinab K.,Zekri, Abdel Rahman N.,Gaber, Ayman A.,Rejaie, Salem S. Al,Sayed-Ahmed, Mohamed M.,Shabanah, Othman Al Asian Pacific Organization for Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.2

          Aim and background: MicroRNAs (miRNAs) are a class of naturally occurring small noncoding RNAs that regulate gene expression, cell growth, differentiation and apoptosis by targeting mRNAs for translational repression or cleavage. The present study was conducted to study miRNAs in Egyptian breast cancer (BC) and their relation to metastasis, tumor invasion and apoptosis in addition to their association with the ER and PR statuses. Methods: Real Time RT-PCR was performed to identify the miRNA expression level of eight miRNAs and eight metastatic-related genes in 40 breast cancer samples and their adjacent non-neoplastic tissues. The expression levels of each miRNA relative to U6 RNA were determined using the $^{2-{\Delta}}CT$ method. Also, miRNA expression profiles of the BC and their corresponding ANT were evaluated. Results: The BC patients showed an up-regulation in miRNAs (mir-155, mir-10, mir-21 and mir-373) with an upregulation in MMP2, MMp9 and VEGF genes. We found down regulation in mir-17p, mir-126, mir-335, mir-30b and also TIMP3, TMP1 and PDCD4 genes in the cancer tissue compared to the adjacent non-neoplastic tissues. Mir -10b, mir -21, mir-155 and mir373 and the metastatic genes MMP2, MMP9 and VEGF were significantly associated with an increase in tumor size (P < 0.05). No significant difference was observed between any of the studied miRNAs regarding lymph node metastasis. Mir-21 was significantly over-expressed in ER-/PR-cases. Conclusion: Specific miRNAs (mir-10, mir-21, mir-155, mir-373, mir-30b, mir-126, mir-17p, mir-335) are associated with tumor metastasis and other clinical characteristics for BC, facilitating identification of individuals who are at risk.

        • SCOPUSKCI등재

          Dexmedetomidine during suprazygomatic maxillary nerve block for pediatric cleft palate repair, randomized double-blind controlled study

          Mostafa, Mohamed F.,Aal, Fatma A. Abdel,Ali, Ibrahim Hassan,Ibrahim, Ahmed K.,Herdan, Ragaa The Korean Pain Society 2020 The Korean Journal of Pain Vol.33 No.1

          Background: For children with cleft palates, surgeries at a young age are necessary to reduce feeding or phonation difficulties and reduce complications, especially respiratory tract infections and frequent sinusitis. We hypothesized that dexmedetomidine might prolong the postoperative analgesic duration when added to bupivacaine during nerve blocks. Methods: Eighty patients of 1-5 years old were arbitrarily assigned to two equal groups (forty patients each) to receive bilateral suprazygomatic maxillary nerve blocks. Group A received bilateral 0.2 mL/kg bupivacaine (0.125%; maximum volume 4 mL/side). Group B received bilateral 0.2 mL/kg bupivacaine (0.125%) + 0.5 ㎍/kg dexmedetomidine (maximum volume 4 mL/side). Results: The modified children's hospital of Eastern Ontario pain scale score was significantly lower in group B children after 8 hours of follow-up postoperatively (P < 0.001). Mean values of heart rate and blood pressure were significantly different between the groups, with lower mean values in group B (P < 0.001). Median time to the first analgesic demand in group A children was 10 hours (range 8-12 hr), and no patients needed analgesia in group B. The sedation score assessment was higher in children given dexmedetomidine (P = 0.03) during the first postoperative 30 minutes. Better parent satisfaction scores (5-point Likert scale) were recorded in group B and without serious adverse effects. Conclusions: Addition of dexmedetomidine 0.5 ㎍/kg to bupivacaine 0.125% has accentuated the analgesic efficacy of bilateral suprazygomatic maxillary nerve block in children undergoing primary cleft palate repair with less postoperative supplemental analgesia or untoward effects.

        • KCI등재

          Computational Studies on the Reaction from Silyl 1,4-Dilithio 1,3-butadiene to Lithio Silole

          김창곤,Ahmed A. K. Mohammed,Eugene Wee,손창국,김찬경 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.1

          The reaction mechanisms forming lithio silole, 2, from silyl 1,4-dilithio 1,3-butadiene, 1, were examined theoretically at the CCSD/6-31+G(d)//B3LYP/6-31+G(d) level of theory in the gas phase. To account for the solvent effects, the reactions in diethyl ether were examined using the polarizable continuum model of the integral equation formalism (IEFPCM) with the united atom topological (UA0) cavity model at the IEFPCM-CCSD/6-31+G(d)//IEFPCM-B3LYP/6-31+G(d) level of theory. Without hexamethyl-phosphoramide (HMPA) as a cosolvent, the lithio silole, 2, was not produced due to the higher activation barrier, which is comparable to the homolytic cleavage of CC and/or CS bonds. On the other hand, the reaction could be feasible if HMPA solvates strongly or dissociates two Li+ cations from the reaction system. This suggests that HMPA plays a decisive role in the reaction. The optimized structures of the stationary point species on the potential energy surfaces in diethyl ether were similar to those in the gas phase, suggesting that the solvent effects on the structures of stationary species were not so large. On the other hand, theΔ E ZPVE ≠ values in diethyl ether showed larger changes from the corresponding values in the gas phase.

        • KCI등재

          The impact of omeprazole on mycophenolate pharmacokinetics in kidney transplant recipients

          AbdElhalim Mohamed S.,Kenawy Ahmed S.,Demellawy Heba H. El,Azouz Amany A.,Alghanem Sarah S.,Al-Otaibi Torki,Gheith Osama,ElMonem Mohamed Abd,Afifi Mohammed K.,Hussein Raghda R. S. 대한신장학회 2020 Kidney Research and Clinical Practice Vol.39 No.4

          Background: Infection is the second leading cause of death in patients undergoing long-term dialysis. Peritoneal dialysis (PD) is associated with an increased risk of infection-related hospitalization (IRH) when compared with hemodialysis. In this study, we investigated the influence of IRH on clinical outcomes in incident PD patients. Methods: In total, 583 incident PD patients were selected from the Clinical Research Center Registry for End-Stage Renal Disease, a nationwide multicenter prospective observational cohort study in Korea. Incident PD patients who had been hospitalized for infection-related diseases were defined as the IRH group. The primary outcome was allcause mortality and the secondary outcome was technical failure. The median follow-up period was 29 months. Results: Seventy-three PD patients (12.5%) were categorized in the IRH group. Multivariable logistic regression analysis showed that diabetes mellitus was a significant independent predictor for IRH (odds ratio, 2.43; 95% confidence interval [CI], 1.12 to 5.29; P = 0.007). The most common causes of IRH were peritonitis (63.0%) and respiratory tract infection (9.6%). Multivariable Cox proportional hazard model analysis showed that IRH was a significant independent risk factor for all-cause mortality (hazard ratio [HR], 2.51; 95% CI, 1.12 to 5.62; P = 0.026) and for the technical failure of PD (HR, 3.23; 95% CI, 1.90 to 5.51; P < 0.001). Conclusion: Our data showed that after initiation of PD, IRH was significantly associated with higher risk of all-cause mortality and technical failure.

        • Increased Hypermethylation of Glutathione S-Transferase P1, DNA-Binding Protein Inhibitor, Death Associated Protein Kinase and Paired Box Protein-5 Genes in Triple-Negative Breast Cancer Saudi Females

          Hafez, Mohamed M.,Al-Shabanah, Othman A.,Al-Rejaie, Salim S.,Al-Harbi, Naif O.,Hassan, Zeinab K.,Alsheikh, Abdulmalik,Theyab, Abdurrahman I. Al,Aldelemy, Meshan L.,Sayed-Ahmed, Mohamed M. Asian Pacific Organization for Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.2

          Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer (BC) with higher metastatic rate and both local and systemic recurrence compared to non-TNBC. The generation of reactive oxygen species (ROS) secondary to oxidative stress is associated with DNA damage, chromosomal degradation and alterations of both hypermethylation and hypomethylation of DNA. This study concerns differential methylation of promoter regions in specific groups of genes in TNBC and non-TNBC Saudi females in an effort to understand whether epigenetic events might be involved in breast carcinogenesis, and whether they might be used as markers for Saudi BCs. Methylation of glutathione S-transferase P1 (GSTP1), T-cadherin (CDH13), Paired box protein 5 (PAX5), death associated protein kinase (DAPK), twist-related protein (TWIST), DNA-binding protein inhibitor (ID4), High In Normal-1 (HIN-1), cyclin-dependent kinase inhibitor 2A (p16), cyclin D2 and retinoic acid receptor-${\beta}$ ($RAR{\beta}1$) genes was analyzed by methylation specific polymerase chain reaction (MSP) in 200 archival formalin-fixed paraffin embedded BC tissues divided into 3 groups; benign breast tissues (20), TNBC (80) and non-TNBC (100). The relationships between methylation status, and clinical and pathological characteristics of patients and tumors were assessed. Higher frequencies of GSTP1, ID4, TWIST, DAPK, PAX5 and HIN-1 hypermethylation were found in TNBC than in non-TNBC. Hypermethylation of GSTP1, CDH13, ID4, DAPK, HIN-1 and PAX5 increased with tumor grade increasing. Other statistically significant correlations were identified with studied genes. Data from this study suggest that increased hypermethylation of GSTP1, ID4, TWIST, DAPK, PAX5 and HIN-1 genes in TNBC than in non-TNBC can act as useful biomarker for BCs in the Saudi population. The higher frequency of specific hypermethylated genes paralleling tumor grade, size and lymph node involvement suggests contributions to breast cancer initiation and progression.

        맨 위로 스크롤 이동