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RISS 인기검색어
- 검색키워드
- 저자 : Reham Mohamed (검색결과 9 건)
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Enhanced oxygen evolution reaction over glassy carbon electrode modified with NiOx and Fe3O4
Reham Helmy Tammam,Amany Mohamed Fekry,Mahmoud Mohamed Saleh 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.11
Magnetite iron oxide (Fe3O4)/nickel oxide (NiOx) modified glassy carbon (GC) electrode shows enhancement of oxygen evolution reaction (OER) compared to GC electrode modified with single NiOx or Fe3O4 nanoparticles. Many techniques such as linear and cyclic sweep voltammetry, electrochemical impedance spectroscopy (EIS) have been employed. Field-emission scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) are both used for characterization of the electrocatalysts. Effect of loading amount of both NiOx and Fe3O4 and the order of deposition on the OER was studied. A significant improvement of the electrocatalytic properties of the Fe3O4/NiOx binary catalyst modified GC is obtained when NiOx is electrodeposited on GC/Fe3O4 (i.e. GC/Fe3O4/NiOx) compared to GC/NiOx/Fe3O4 (where NiOx is deposited first on the GC then Fe3O4). The use of GC/Fe3O4/NiOx (where Fe3O4 is deposited first on the GC then NiOx) for OER in alkaline solution support higher currents and consequently negative shifts of the onset potential of OER compared to that of GC/NiOx or GC/Fe3O4. The obtained electrochemical impedance parameters confirmed the above conclusions. Tafel parameters confirm the superior activity of GC/Fe3O4/ NiOx and give insight into the mechanism of the OER on the above electrodes.
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Machine Learning Model for Predicting Postoperative Survival of Patients with Colorectal Cancer
Mohamed Hosny Osman,Reham Hosny Mohamed,Hossam Mohamed Sarhan,박은정,백승혁,이강영,강정현 대한암학회 2022 Cancer Research and Treatment Vol.54 No.2
Purpose Machine learning (ML) is a strong candidate for making accurate predictions, as we can use large amount of data with powerful computational algorithms. We developed a ML based model to predict survival of patients with colorectal cancer (CRC) using data from two independent datasets. Materials and Methods A total of 364,316 and 1,572 CRC patients were included from the Surveillance, Epidemiology, and End Results (SEER) and a Korean dataset, respectively. As SEER combines data from 18 cancer registries, internal validation was done using 18-Fold-Cross-Validation then external validation was performed by testing the trained model on the Korean dataset. Performance was evaluated using area under the receiver operating characteristic curve (AUROC), sensitivity and positive predictive values. Results Clinicopathological characteristics were significantly different between the two datasets and the SEER showed a significant lower 5-year survival rate compared to the Korean dataset (60.1% vs. 75.3%, p < 0.001). The ML-based model using the Light gradient boosting algorithm achieved a better performance in predicting 5-year-survival compared to American Joint Committee on Cancer stage (AUROC, 0.804 vs. 0.736; p < 0.001). The most important features which influenced model performance were age, number of examined lymph nodes, and tumor size. Sensitivity and positive predictive values of predicting 5-year-survival for classes including dead or alive were reported as 68.14%, 77.51% and 49.88%, 88.1% respectively in the validation set. Survival probability can be checked using the web-based survival predictor (http://colorectalcancer.pythonanywhere.com). Conclusion ML-based model achieved a much better performance compared to staging in individualized estimation of survival of patients with CRC. Purpose Machine learning (ML) is a strong candidate for making accurate predictions, as we can use large amount of data with powerful computational algorithms. We developed a ML based model to predict survival of patients with colorectal cancer (CRC) using data from two independent datasets.Materials and Methods A total of 364,316 and 1,572 CRC patients were included from the Surveillance, Epidemiology, and End Results (SEER) and a Korean dataset, respectively. As SEER combines data from 18 cancer registries, internal validation was done using 18-Fold-Cross-Validation then external validation was performed by testing the trained model on the Korean dataset. Performance was evaluated using area under the receiver operating characteristic curve (AUROC), sensitivity and positive predictive values.Results Clinicopathological characteristics were significantly different between the two datasets and the SEER showed a significant lower 5-year survival rate compared to the Korean dataset (60.1% vs. 75.3%, p < 0.001). The ML-based model using the Light gradient boosting algorithm achieved a better performance in predicting 5-year-survival compared to American Joint Committee on Cancer stage (AUROC, 0.804 vs. 0.736; p < 0.001). The most important features which influenced model performance were age, number of examined lymph nodes, and tumor size. Sensitivity and positive predictive values of predicting 5-year-survival for classes including dead or alive were reported as 68.14%, 77.51% and 49.88%, 88.1% respectively in the validation set. Survival probability can be checked using the web-based survival predictor (http://colorectalcancer.pythonanywhere.com).Conclusion ML-based model achieved a much better performance compared to staging in individualized estimation of survival of patients with CRC.
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ANTECEDENTS AND OUTCOME OF CUSTOMER ENGAGEMENT WITH THE HOTEL BRAND COMMUNITIES EMBEDDED IN FACEBOOK
Reham Touni,Woody G. Kim,Hyung-Min Choi,Mohamed Ali 글로벌지식마케팅경영학회 2018 Global Marketing Conference Vol.2018 No.07
Since social media has become an essential tool in the contemporary hotel industry, companies are now building social media communities to engage customers online (Leung & Bai, 2013) and to maintain satisfaction, trust, commitment, loyalty, and brand relationship quality (Harrigan, Evers, Miles, & Daly, 2017). Despite global hotel companies’ increasing adoption of social media platforms to promote customer engagement, research in this area is still sparse (Harrigan et al., 2017; So, King, & Sparks, 2014). To fill this gap, the authors developed a theoretical model incorporating two antecedents (hotel brand experience and customer involvement to social media) and a consequence (brand relationship quality) of customer engagement (CE) in the context of hotel brand communities embedded in social media. Additionally, the authors included hotel brand reputation (HBR) in the model as another predictor of brand relationship quality (BRQ). This study obtained data from a panel survey consisting of the responses of hotel customers who had stayed at one of ten famous hotel brands in the U.S. within the past 12 months and were simultaneously followers of the hotel brand’s page on Facebook. The findings reveal that both antecedents (ISM and HBX) positively and significantly influence CE and that hotel brand experience (HBX) has a stronger impact on CE than ISM. The findings also demonstrate that CE has the strongest, positive effect on BRQ, followed by HBX and HBR. Furthermore, the findings indicate that the relationship between HBX and BRQ is partially and significantly mediated by CE. This research provides theoretical and practical contributions to the field. First, unlike previous studies, the current study utilized the concept of CE with hotel brand communities embedded in social media as a mediator between HBX and BRQ and found partial and significant mediation effects. Second, the study identified two new and crucial antecedents of CE with brand communities embedded in social media—customer brand experience and customer social media involvement. Third, this study found brand relationship quality as one of the primary outcomes of customer engagement with hotel brand communities in social media. Lastly, the findings confirm that social media-based brand communities (i.e., Facebook) are one tool companies can use to build long-lasting customer-brand relationships.
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El Nemr Esmail, Reham Shehab,El Farouk Abdel-Salam, Lubna Omer,Abd El Ellah, Mohammed M Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.10
Background: Prognostic biomarkers in breast cancer are routinely investigated in the primary tumors to guide further management. However, it is proposed that the expression may change during the disease progression, and may result in a different immune profile in the metastatic nodes. This work aimed to investigate the expression of breast prognostic biomarkers in primary tumors and in its axillary nodal metastasis, to estimate the possible discordant expression. Materials and Methods: 60 paired primary and axillary nodal metastasis samples were collected from patients with primary breast cancer with positive nodal deposits, diagnosed at the Maadi Military Hospital, Cairo, Egypt, during the year 2013. ER, PR and HER2 expression was assessed by immunohistochemistry in all samples Results: 48.3% of the included cases showed concordant results for both ER and PR receptors between the primary tumor and its nodal metastasis while 51.7% showed discordant results and the discordance level was statistically significant. On the other hand, 70% of the cases showed concordant Her2 results between the primary tumors and the nodal deposits, 30% showed discordant results and the difference was significant. Conclusions: The study indicated that the discordance in ER and PR receptor expression between the primary breast tumor and their nodal metastasis may be significant. The possible switch in the biomarker status during the disease progression is worth noting and may change the patient therapeutic planning. So, whether the treatment selection should be based on biomarkers in the lymph node is a topic for further studies and future clinical trials.
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Zekri, Abdel-Rahman,Youssef, Amira Salah El-Din,Bakr, Yasser Mabrouk,Gabr, Reham Mohamed,El-Rouby, Mahmoud Nour El-Din,Hammad, Ibtisam,Ahmed, Entsar Abd El-Monaem,Marzouk, Hanan Abd El-Haleem,Nabil, M Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.3
Background: Early detection of hepatocellular carcinoma using serological markers with better sensitivity and specificity than alpha fetoprotein (AFP) is needed. Aims: The aim of this study was to evaluate the diagnostic value of serum sICAM-1, ${\beta}$-catenin, IL-8, proteasome and sTNFR-II in early detection of HCC. Materials and Methods: Serum levels of IL-8, sICAM-1, sTNFR-II, proteasome and ${\beta}$-catenin were measured by ELISA assay in 479 serum samples from 192 patients with HCC, 96 patients with liver cirrhosis (LC), 96 patients with chronic hepatitis C (CHC) and 95 healthy controls. Results: Serum levels of proteasome, sICAM-1, ${\beta}$-catenin and ${\alpha}FP$ were significantly elevated in HCC group compared to other groups (P-value<0.001), where serum level of IL-8 was significantly elevated in the LC and HCC groups compared to CHC and control groups (P-value <0.001), while no significant difference was noticed in patients with HCC and LC (P-value=0.09). Serum level of sTNFR-II was significantly elevated in patients with LC compared to HCC, CHC and control groups (P-value <0.001); also it was significantly higher in HCC compared to CHC and control groups (P-value <0.001). ROC curve analysis of the studied markers between HCC and other groups revealed that the serum level of proteasome had sensitivity of 75.9% and specificity of 73.4% at a cut-off value of $0.32{\mu}g/ml$ with AUC 0.803 sICAM-1 at cut off value of 778ng/ml, the sensitivity was 75.8% and the specificity was 71.8% with AUC 0.776. ${\beta}$-catenin had sensitivity and specificity of 70% and 68.6% respectively at a cut off value of 8.75ng/ml with an AUC of 0.729. sTNFR-II showed sensitivity of 86.3% and specificity of 51.8% at a cut off value of 6239.5pg/ml with an AUC of 0.722. IL-8 had sensitivity of 70.4% and specificity of 52.3% at a cut off value of 51.5pg/ml with AUC 0.631. Conclusions: Our data supported the role of proteasome, sICAM-1, sTNFR-II and ${\beta}$-catenin in early detection of HCC. Also, using this panel of serological markers in combination with ${\alpha}FP$ may offer improved diagnostic performance over ${\alpha}FP$ alone in the early detection of HCC.
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Zyoud, Ahed,AlKerm, Rana S.,Alkerm, Rola S.,Abdelhadi, Doa׳,H.,Park, DaeHoon,Helal, Mohammed H.S.,Campet, Guy,Muthaffar, Reham W.,Kwon, Hansang,Hilal, Hikmat S. North-Holland 2016 Solar Energy Materials and Solar Cells Vol. No.
<P><B>Abstract</B></P> <P>High conversion efficiency (<I>η</I>) values have been obtained from modified CuS film electrodes electrochemically deposited onto Glass/FTO. The modification involved pre-annealing the film followed by coating with tetra(-4-pyridyl)porphyrinato manganese (MnTPyP<SUP>+</SUP>) ions embedded inside a polyethylene (PE) matrix. The Glass/FTO/CuS/MnTPyP/PE electrodes exhibited enhanced photo-electrochemical (PEC) characteristics under solar simulated illumination (5.6mW/cm<SUP>−2</SUP>) in aqueous media, compared to the as-prepared Glass/FTO/CuS films which showed no PEC activity. Up to 17.4% efficiency and 85% fill factor (FF) values were obtained from the modified film electrodes. Such characteristics have not been widely known for metal chalcogenide based film electrodes before. Different pre-annealing temperatures were attempted and the 250°C temperature, followed by quenching, showed favorable results. Different aqueous redox couples were studied and the environmentally safe FeCl<SUB>2</SUB>/FeCl<SUB>3</SUB> aqueous system showed highest PEC characteristics. Effect of pre-annealing on film electrode characteristics is discussed. The MnTPyP/PE matrix behaves as charge transfer catalyst for the holes across the CuS film/liquid junction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CuS film electrodes were coated with metalloporphyrinato manganese(III)/polyethylene matrices. </LI> <LI> High PEC characteristics have been exhibited by the modified electrodes. </LI> <LI> Modification enhanced both film electrode stability and efficiency together. </LI> <LI> The matrix behaved as charge transfer catalyst for holes at the solid/liquid interface. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Annealing CuS film electrodes at moderate temperatures (preferably at 250°C) affects CuS film morphology and spectral properties, and coating with metalloporphyrin/polymer matrices enhanced their PEC efficiency and stability.</P> <P>[DISPLAY OMISSION]</P>
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