9 results on '"Al Ahmar E"'
Search Results
2. Advanced signal processing techniques for fault detection and diagnosis in a wind turbine induction generator drive train: A comparative study
- Author
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Al Ahmar, E., primary, Choqueuse, V., additional, Benbouzid, M.E.H., additional, Amirat, Y., additional, El Assad, J., additional, Karam, R., additional, and Farah, S., additional
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- 2010
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3. DFIG-based wind turbine fault diagnosis using a specific discrete wavelet transform
- Author
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Al-Ahmar, E., primary, Benbouzid, M.E.H., additional, Amirat, Y., additional, and Elghali, S.E. Ben, additional
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- 2008
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4. Wind Energy Conversion Systems Fault Diagnosis Using Wavelet Analysis.
- Author
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Al-Ahmar, E., Benbouzid, M. E. H., and Turri, S.
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WIND energy conversion systems ,ELECTRIC fault location ,WAVELETS (Mathematics) ,INDUCTION generators ,WIND turbines - Abstract
This paper deals with the investigation of a specific transient technique suitable for electrical and mechanical failure diagnosis in an induction generator based wind turbine. The investigated technique is a combination of the Discrete Wavelet transform, statistics and the energy. Experimental investigations carried out on a 1.1 kW induction generator based test bench show that the proposed technique can unambiguously diagnose failures under transient conditions. [ABSTRACT FROM AUTHOR]
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- 2008
5. Effects of Cannabis Use on Neurocognition: A Scoping Review of MRI Studies.
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Audi D, Hajeer S, Saab MB, Saab L, Harati H, Desoutter A, Al Ahmar E, and Estephan E
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Cannabis is one of the most commonly utilized recreational drugs. However, increasing evidence from the literature suggests harmful implications on cognition. Thus, the main aim of the current review is to summarize literature findings pertaining to the impact of cannabis on neurocognitive skills, focusing on the imaging biomarkers provided by MRI. Two reviewers navigated the literature independently using four main search engines including PubMed and Cochrane. Articles were first evaluated through their title and abstract, followed by full-text assessment. Study characteristics and findings were extracted, and the studies' quality was appraised. 47 articles were included. The majority of the studies were of a case-control design (66%), and the most studied neurocognitive skill was memory (40.4%). With task-based fMRI being the most commonly utilized MRI technique, findings have shown significantly varying decreased and increased neuronal activity within brain regions associated with the cognitive tasks performed. Results suggest that cannabis users are significantly suffering from cognitive deficits. The major significance of this review is attributed to highlighting the role of MRI. Future research needs to delve more into validating the negative effects of cannabis, to enable stakeholders to take action to limit cannabis usage, to foster public health and wellbeing.
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- 2024
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6. Evaluation of the accuracy of new modalities in the assessment and classification of lumbar lordosis: A comparison to Cobb's angle measurement.
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Eddine HK, Saleh S, Hajjar J, Harati H, Nasser Z, Desoutter A, Al Ahmar E, and Estephan E
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Background: Because of the association of lumbar lordosis with some clinical conditions such as low back pain, the chiropractic field has emphasized the significance of evaluating the lumbar lordotic status, by measuring Cobb's angle, regarded as the radiological gold standard, for the assessment of lumbar lordosis, on lateral radiographs. However, research has shown that this technique has some considerable drawbacks, mostly in terms of low accuracy and high variability between clinicians when compared with other radiological modalities. The main objective was to compare the diagnostic accuracy of newly established radiological measurements with one of Cobb's angle methods, for the characterization of lumbar lordosis status in a sample of Lebanese patients aged 15 and above., Material and Methods: This retrospective single-center study consisted of measuring Cobb's L1-S1 and Cobb's L1-L5 angles, along with the novel established measurements which are the derivative and the normalized surface area, on 134 lateral radiographs of the lumbar spine of Lebanese patients aged fifteen years old and above, gotten from the Radiology department at Zahra'a's Hospital in Beirut, performed by two observers using MATLAB. Inter-rater agreement was assessed by calculating the Intra-class correlation coefficients. Spearman correlation was analyzed between both Cobb's angle methods and with the derivative and normalized area respectively. 54 patients of the sample were diagnosed by two radiologists, according to their LL status. ROC curve analysis was performed to compare the diagnostic accuracy of the four techniques used. Data were analyzed with IBM SPSS Statistics 23.0 (NY, USA); P < 0.05 was considered statistically significant., Results: According to the ROC curve analysis the new methods, which are the derivative and the normalized surface area, displayed lower diagnostic accuracy (AUC
derivative = 0.818 and 0.677, AUCsurface area = 0.796 and 0.828) than Cobb's L1-L5 (AUCL1-L5 = 0.924 and 0.929 values) and L1-S1 (AUCL1-S1 = 0.971 and 0.955) angles, in the characterization of hypo and hyperlordotic patients, respectively, in our Lebanese sample consisting of patients aged 15 and above, because of their lower area under the curve's values compared to the traditional Cobb's techniques. The Cobb's L1-S1 has shown to have the highest diagnostic accuracy among the four methods to characterize normal patients from hypo and hyperlordotic ones, by referring to its highest area under the curve's values. However, the sensitivity of Cobb's L1-L5 angle in characterizing hyperlordotic patients was similar to the one of the normalized surface area with a value of 100%.Conclusion: among the four modalities, the new methods didn't show a better diagnostic accuracy compared to the traditional modalities. Cobb's L1-S1 displayed the highest diagnostic accuracy despite its drawbacks. Further prospective studies are needed to validate the cut-offs obtained for Cobb's L1-S1 angle in our sample., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors. Published by Elsevier Ltd.)- Published
- 2023
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7. Association between vitamin D deficiency and multiple sclerosis- MRI significance: A scoping review.
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Hajeer S, Nasr F, Nabha S, Saab MB, Harati H, Desoutter A, Al Ahmar E, and Estephan E
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Background/objective: Multiple Sclerosis is a common demyelinating disease of the central nervous system. Several studies suggested a link between vitamin D deficiency and multiple sclerosis disease activity, which can be evaluated by magnetic resonance imaging. Thereby, the main objective of the following scoping review is to summarize the magnetic resonance imaging findings assessing the probable effects of vitamin D on MS disease activity., Methodology: PRISMA checklist for systematic reviews and meta-analyses was employed to structure this review. Literature was searched for observational and clinical studies tackling the given matter using several search engines including PubMed, CORE, and Embase. Data was extracted in a systematic manner, and the articles meeting the inclusion criteria were quality-assessed by Jadad scale for randomized clinical trials (RCTs) and Newcastle-Ottawa scale for observational studies., Results: A total of 35 articles were included. Twenty-one (60%) studies noted a statistically significant association between vitamin D and Multiple Sclerosis MRI-detected disease activity. MRI-detected features involved lower contrast-enhancing T1 lesions, lower hyperintense T2 lesions, and a decrease in lesions volume. On the other hand, 40% (14 articles) of the articles did not detect any significant effect of vitamin D on Multiple Sclerosis disease activity. Due to the heterogeneity of the studies involved, meta-analysis was not employed in the given review., Discussion/conclusion: There was an abundance in the number of research studies investigating the relationship between vitamin D and Multiple Sclerosis while highlighting the significant role of MRI in assessing the activity of the disease. Numerous studies found that higher serum vitamin D levels are associated with decreased new active cortical and subcortical lesions and lower lesions volume. These findings highlight the importance of imaging modalities in the various aspects of neurological diseases and encourage further research to focus on the preventive effects of vitamin D on MS patients., (© 2023 The Authors.)
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- 2023
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8. The log odds of positive neck lymph nodes is a superior lymph node predictor for overall survival in head and neck cancer: a population-based analysis in Germany.
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Kouka M, Al-Ahmar E, Büntzel J, Kaftan H, Böger D, Müller A, Schultze-Mosgau S, Ernst T, and Guntinas-Lichius O
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- Germany epidemiology, Humans, Lymphatic Metastasis pathology, Middle Aged, Neoplasm Staging, Prognosis, Head and Neck Neoplasms pathology, Head and Neck Neoplasms surgery, Lymph Nodes pathology
- Abstract
Background: This population-based study investigated the influence of different lymph node (LN) classifications on overall survival (OS) in head and neck cancer (HNC)., Methods: 401 patients (median age: 57 years; 47% stage IV) of the Thuringian cancer registries with diagnosis of a primary HNC receiving a neck dissection (ND) in 2009 and 2010 were included. OS was assessed in relation to total number of LN removed, number of positive LN, LN ratio, and log odds of positive LN (LODDS)., Results: Mean number of LODDS was 0-0.96 ± 0.57. When limiting the multivariate analysis to TNM stage, only the UICC staging (stage IV: HR 9.218; 95% CI 2.721-31.224; p < 0.001) and LODDS > - 1.0 (HR 2.120; 95% CI 1.129-3.982; p = 0.019) were independently associated with lower OS., Conclusion: LODDS was an independent and superior predictor for OS in HNC in a population-based setting with representative real-life data., (© 2021. The Author(s).)
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- 2022
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9. Morphological changes in amblyopic eyes in choriocapillaris and Sattler's layer in comparison to healthy eyes, and in retinal nerve fiber layer in comparison to fellow eyes through quantification of mean reflectivity: A pilot study.
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Masri OS, Abiad B, Darwich MJ, Sarkis PA, El Mollayess GM, Nasser Z, Fares Y, Al Ahmar E, and Estephan E
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- Adolescent, Adult, Amblyopia pathology, Anisometropia diagnostic imaging, Child, Child, Preschool, Choroid diagnostic imaging, Choroid physiology, Choroid ultrastructure, Eye ultrastructure, Female, Humans, Male, Middle Aged, Nerve Fibers pathology, Nerve Fibers ultrastructure, Pilot Projects, Retina pathology, Retina ultrastructure, Retinal Ganglion Cells pathology, Strabismus diagnostic imaging, Strabismus pathology, Tomography, Optical Coherence, Visual Acuity physiology, Young Adult, Amblyopia diagnostic imaging, Anisometropia pathology, Eye diagnostic imaging, Retina diagnostic imaging
- Abstract
Purpose: Establishing the reliability of a new method to check the mean retinal and choroidal reflectivity and using it to find retinal and choroid changes in amblyopia., Methods: Design: Retrospective case-control. Population: 28 subjects of which 10 were healthy controls (20 eyes): 8 with refractive errors, 1 with strabismus, and 1 with both. 18 patients with unilateral amblyopia included: 7 anisometropic, 6 isoametropic, 1 strabismic, and 4 combined. Mean participants' age: 13.77 years ± 10.28. Observation procedures: SD-OCT and ImageJ. Main outcome measure: mean reflectivity of retinal and choroid layers. Amblyopic, fellow, and healthy eyes were compared., Results: The method of measuring reflectivity is good to excellent reliability for all regions of interest except the fourth. The mean reflectivity of the choriocapillaris and Sattler's layer in amblyopic eyes were significantly lower than in healthy eyes (p = 0.003 and p = 0.008 respectively). The RNFL reflectivity was lower than that of fellow eyes (p = 0.025). Post-hoc pairwise comparisons showed statistically significant differences between amblyopic and healthy eyes for choriocapillaris (p = 0.018) and Sattler's (p = 0.035), and between amblyopic and fellow eyes for RNFL (p = 0.039)., Conclusion: A decrease in reflectivity of the choriocapillaris and Sattler's in amblyopic compared to healthy eyes, and a decrease in reflectivity of the RNFL in the amblyopic compared to fellow eyes, indicate that the pathophysiology is partly peripheral and might be bilateral., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2021
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