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Youssef, A. H., A. A. El-sheikh, and M. R. Abonazel, "New GMM Estimators for Dynamic Panel Data Models", International Journal of Innovative Research in Science, Engineering and Technology, vol. 3, issue 10, pp. 16414-16425, 2014. Abstractnew_gmm_estimators_for_dynamic_panel_data_models.pdf

In dynamic panel data (DPD) models, the generalized method of moments (GMM) estimation gives efficient estimators. However, this efficiency is affected by the choice of the initial weighting matrix. In practice, the inverse of the moment matrix of the instruments has been used as an initial weighting matrix which led to a loss of efficiency. Therefore, we will present new GMM estimators based on optimal or suboptimal weighting matrices in GMM estimation. Monte Carlo study indicates that the potential efficiency gain by using these matrices. Moreover, the bias and efficiency of the new GMM estimators are more reliable than any other conventional GMM estimators.

Youssef, A. S. E. - D., M. A. Abdel-Fattah, M. M. Lotfy, A. Nassar, M. Abouelhoda, A. O. Touny, Z. K. Hassan, M. M. Eldin, A. A. Bahnassy, H. Khaled, et al., "Multigene Panel Sequencing Reveals Cancer-Specific and Common Somatic Mutations in Colorectal Cancer Patients: An Egyptian Experience.", Current issues in molecular biology, vol. 44, issue 3, pp. 1332-1352, 2022. Abstract

This study aims at identifying common pathogenic somatic mutations at different stages of colorectal carcinogenesis in Egyptian patients. Our cohort included colonoscopic biopsies collected from 120 patients: 20 biopsies from patients with inflammatory bowel disease, 38 from colonic polyp patients, and 62 from patients with colorectal cancer. On top of this, the cohort included 20 biopsies from patients with non-specific mild to moderated colitis. Targeted DNA sequencing using a customized gene panel of 96 colorectal related genes running on the Ion Torrent NGS technology was used to process the samples. Our results revealed that 69% of all cases harbored at least one somatic mutation. Fifty-seven genes were found to carry 232 somatic non-synonymous variants. The most frequently pathogenic somatic mutations were localized in , , , and In total, 16 somatic mutations were detected in the CRC group and in either the IBD or CP group. In addition, our data showed that 51% of total somatic variants were CRC-specific variants. The average number of CRC-specific variants per sample is 2.4. The top genes carrying CRC-specific mutations are , , , , , and It seems obvious that and genes were the most affected genes with somatic mutations in all groups. Of interest, 85% and 28% of the and deleterious somatic mutations were located in Exon 14 and Exon 3, respectively. Besides, 37% and 28% of the total somatic mutations identified in and were CRC-specific variants, respectively. Moreover, we identified that, in 29 somatic mutations in 21 genes, their association with CRC patients was unprecedented. Ten detected variants were likely to be novel: six in and four variants in . The detected P53, Wnt/βcatenin, Angiogenesis, EGFR, TGF-β and Interleukin signaling pathways were the most altered pathways in 22%, 16%, 12%, 10%, 9% and 9% of the CRC patients, respectively. These results would contribute to a better understanding of the colorectal cancer and in introducing personalized therapies for Egyptian CRC patients.

Youssef, M. A., and A. M. Soliman, "A novel CMOS realization of the differential input balanced output current operational amplifier and its applications", Analog Integrated Circuits and Signal Processing, vol. 44, no. 1: Kluwer Academic Publishers, pp. 37–53, 2005. Abstract15-_2005.pdf

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Youssef, M. M. G., D. Cameron, P. H. Pucher, S. Olsen, and D. Ferguson, "The significance of sentinel lymph node micrometastasis in breast cancer: Comparing outcomes with and without axillary clearance.", Breast (Edinburgh, Scotland), vol. 30, pp. 101-104, 2016 Dec. Abstract

BACKGROUND: Management of micrometastasis in the sentinel node is a controversial topic. Most of the guidelines don't recommend further axillary treatment if micrometastasis are the only finding in the sentinel node. However, some evidence suggests that micrometastasis have significant effect on long term outcomes and therefore indicate systemic treatment.

METHOD: Retrospective cohort study reviewing the management of patients with micrometastasis in the sentinel nodes. Two groups were compared, those who had further axillary clearance and those who had not. The primary endpoints were loco-regional recurrence and lymphedema rate. The secondary endpoints were distant metastasis rate, OS and DFS.

RESULTS: 95 patients were found to have micrometastasis or ITC in the axillary SNB over a period of 10 years. Of those, 38 patients had axillary clearance after SNB, while 57 did not. Lymphedema rate was 18.4% in the axillary clearance group versus 0% in the no axillary clearance group (p < 0.001). The LRR event was rare therefore not compared. Distant metastasis rate was 7.01% in the SNB group versus 2.6% in the axillary clearance group. There were no mortalities in the axillary clearance group. This compares to 7.01% among the patients who didn't have axillary clearance. All the patients who died had developed distant metastasis as a cause of death. There was a difference in OS between the two groups in favor of the axillary clearance group (p = 0.004).

DISCUSSION: Although not an indication for axillary clearance recent guidelines, micrometastasis and ITC found in the SNB are a sign of a biologically different disease. This important information should be taken in consideration when planning the adjuvant treatment in those patients among other factors considered.

Youssef, R., O. A. M. Zeid, N. E. S. R. I. N. SAMIR, R. A. Zayed, and D. Omran, "Interferon alpha, gamma, and lambda 2: are they possible culprits in the association between psoriasis and hepatitis C virus?", Journal of the Egyptian Women's Dermatologic Society, vol. 16, pp. 51-55, 2019.
Youssef, N. F. A., and A. D. A. Hassan, "The Effect of hand and foot massage on alleviating pain and anxiety of abdominal post-operative patients at a University Hospital: A randomized control trial", Journal of Nursing and Health Science, vol. 7, no. 3: IOSR, pp. 56–65, 2017. Abstract
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Youssef, A., and R. Kamel, "Ultrasound in labor: impact of a theoretical and practical course on caregiver’s perspective and accuracy", The Journal of Maternal-Fetal & Neonatal Medicine, vol. 33, issue 18: Taylor & Francis, pp. 3163-3169, 2020. Abstract
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Youssef, A. R., T. Leonard, and W. Herzog, "Effects of Hind Limb Muscle Weakness on Tibial Cartilage Degeneration in Rabbits", CSB/SCB 2010, Queen’s University, Kingston, 2010.
Youssef, A. R., A. M. A. Ibrahim, and K. E. S. Ayad, "Mulligan Mobilization Is More Effective in Treating Diabetic Frozen Shoulder Than the Maitland Technique", International journal of physiotherapy, vol. 2, issue 5, pp. 804-810, 2015.
Youssef, A., Y. M. Issa, O. R. Shehab, and H. Sherief, "Determination of Microgram Amounts of Copper in Real Samples Using New Modified Carbon Paste Electrode", Inter. J. Electrochem. Sci.,, vol. 10, pp. 4752-4769, 2015.
Youssef, S. A., Youssef, S. A., Refai, M., M. Taha, and E.: Barakat, " Fungi in the air of different departments of Ain Shams Hospital. ", Ain Shams Med. J., vol. 31, , pp. 245-255 , 1980. fungi_in_air_of_ain_shams.pdf
Youssef, N., H. N. Deif, M. Hashad, M. El-Hariri, and K. Al-Amry, "Diagnostic Potential of GeneXpert MTB/RIF Assay for Mycobacterium bovis Infection in Bovine: A Retrospective Study", Egyptian Journal of Veterinary Sciences, vol. 55, issue 2, pp. 467-472, 2023.
Youssef, T., M. Fadel, R. Fahmy, and K. Kassab, "Evaluation of hypericin-loaded solid lipid nanoparticles: Physicochemical properties, photostability and phototoxicity. ", Pharmaceutical Development and Technology, vol. 17, issue 2, pp. 177-186, 2012.
Youssef, D., and N. Solouma, "Accurate Detection of Blood Vessels I mproves the Detection of Exudates in Color Fundus Images", Computer methods and programs in biomedicine, vol. 108, pp. 1052–1061, 2012.
Youssef, N., C. Best, W. G. Mackay, S. Hagen, and Ashley Shepherd, "Psychometric properties of the Arabic version of the International Consultation on Incontinence Questionnaire on Long-Term Catheter Quality of Life.", International journal of nursing practice, vol. 26, issue 3, pp. e12807, 2020. Abstract

AIM: To translate the International Consultation on Incontinence Questionnaire (ICIQ) Long-Term Catheter Quality of Life (LTCqol) questionnaire (ICIQ-LTCqol) from English to Arabic and evaluate its psychometric properties.

BACKGROUND: Currently, no tool for Arabic-speaking patients is available to measure the quality of life in patients using long-term urinary catheters.

DESIGN: Translation and psychometric assessment of questionnaire.

METHODS: The internal consistency and construct validity of the translated Arabic version of the ICIQ-LTCqol were evaluated in a convenience sample of 141 participants recruited from a hospital in Egypt from April to September 2017. Test-retest reliability was assessed for a sample of 15 participants who completed this version at two time points. Construct validity was assessed by factor analysis.

RESULTS: The translated Arabic version of the ICIQ-LTCqol showed satisfactory test-retest reliability and internal consistency, with the Cronbach α = .75. Confirmatory factor analysis confirmed the same two factors ("catheter function" and "lifestyle") structure as found in the English version of the tool supporting the construct validity of the translated questionnaire.

CONCLUSION: This original and significant study allows, for the first time, researchers and clinicians working with Arabic-speaking patients, the opportunity to evaluate the quality of life in long-term urinary catheter users.

Youssef, N. L., A. Soleiman, and E. H. Taha, "New conformal invariants in absolute parallelism geometry", Int. J. Geom. Meth. Mod. Phys., vol. 15, issue 1, 2018.
Youssef, I. M., A. I. Elsherbeni, A. A. Almuraee, N. M. Nass, E. A. Beyari, N. M. Alshammarii, A. M. Abdel-Ghany, E. - S. G. Ahmed, S. Nasr, and K. M. Youssef, "Influence of using synbiotics by various routes on Mandarah male chicks: intestinal bacterial counts, gut morphology and histological status", Poultry Science, vol. 103, issue 5: Elsevier, pp. 103601, 2024. Abstract
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Youssef, R. M., D. Mahgoub, H. M. Mashaly, E. El-Nabarawy, N. Samir, and M. El-Mofty, "Different narrowband UVB dosage regimens in dark skinned psoriatics: a preliminary study", Photodermatology, photoimmunology & photomedicine, vol. 24, no. 5: Wiley Online Library, pp. 256–259, 2008. Abstract
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Youssef, H. K. M., A. M. Ibrahim, S. H. E. A. Aleem, and E. M. M. A. Hady, A Methodology for Low-Cost Optimization of Energy Efficient Passive Filters in Distribution Networks, , 2014. Abstract

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Youssef, N. M. A., A. El-Sanousi, F. M. Mohamed, M. A. Shalaby, H. A. A. Mousa, S. A. H. Salem, M. S. Saber, and S. M. Saleh, "Estimation of rotavirus antibodies in vaccinated cattle and their neonates", Veterinary Medical Journal Giza, Cairo Univ.(Egypt), 1994. Abstract
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Youssef, M., H. AbdelMoety, H. A. Ashmawi, and N. Sherif, "Oral antioxidants supplementation for women with unexplained infertility undergoing ICSI/IVF: Randomized controlled trial", Human Fertility, 2014.
Youssef, S. Y., S. Yasien, W. M. A. Mousa, S. M. Nasr, E. A. M. El-Kelesh, K. M. Mahran, and A. H. Abd-El-Rahman, "Vector identification and clinical, hematological, biochemical, and parasitological characteristics of camel (Camelus dromedarius) theileriosis in Egypt.", Tropical animal health and production, vol. 47, issue 4, pp. 649-56, 2015 Apr. AbstractFull-text

The objectives of the present study were to identify a possible tick vector and to determine the prevalence of camel theileriosis in Egypt using blood smears stained with Giemsa's stain and PCR assay. Hemogram and serum biochemical constituents were also investigated. A total of 243 camels, aged 3-5 years, were examined. The results revealed that 75 (30.86 %) camels were infected with Theileria spp. of Giemsa-stained blood smears. Hyalomma dromedarii was identified as the carrier tick of Theileria spp. Multinucleated sporoblast and free sporozoite were observed in the salivary gland smears from collecting ticks. PCR result revealed that Theileria annulata was the most abundant in camels (60 %) followed by Theileria spp. (10 %). Macrocytic hypochromic anemia was recorded in the infected camels with T. annulata. Leukocytosis, neutrophilia, eosinophilia, and lymphopenia were also observed in the infected group. In the serum of infected camels, total proteins, albumin, β-globulin, and A/G ratio were significantly decreased (P < 0.05); however, total globulins and α- and γ-globulins were markedly increased (P < 0.05). The activity of aspartate aminotransferase and the levels of glucose, creatinine, and high-density lipoprotein cholesterol were markedly increased (P < 0.05) in the infected group. In contrast, triglycerides and total cholesterol concentrations were significant decreased (P < 0.001) in the infected group. In conclusion, a high prevalence of camel theileriosis was recorded in apparently healthy camels. H. dromedarii commonly infested these camels and were found infected with the transmissible forms of Theileria, indicating a role in transmission. Camels infected with T. annulata induced alterations in the cellular and biochemical constituents.

Youssef, L., "“Cultural Contexts: Egyptian Translators of English Romantic Poetry.” ", Cairo Studies: The Department of English Language and Literature, Faculty of Arts, Cairo University, vol. Special Edition, 2002.
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