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Search Results: 1 - 10 of 652 matches for " Zahi Abou Chacra "
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Prevalence of K-RAS Codons 12 and 13 Mutations in Locally Advanced Head and Neck Squamous Cell Carcinoma and Impact on Clinical Outcomes
Eric Bissada,Olivier Abboud,Zahi Abou Chacra,Louis Guertin,Xiaoduan Weng,Phuc Félix Nguyen-Tan,Jean-Claude Tabet,ève Thibaudeau,Louise Lambert,Marie-Lise Audet,Bernard Fortin,Denis Soulières
International Journal of Otolaryngology , 2013, DOI: 10.1155/2013/848021
Abstract: Background. RAS gene mutations have an impact on treatment response and overall prognosis for certain types of cancer. Objectives. To determine the prevalence and impact of K-RAS codons 12 and 13 mutations in patients with locally advanced HNSCC treated with primary or adjuvant chemo-radiation. Methods. 428 consecutive patients were treated with chemo-radiation therapy and followed for a median of 37 months. From these, 199 paraffin embedded biopsy or surgical specimens were retrieved. DNA was isolated and analyzed for K-RAS mutational status. Results. DNA extraction was successful in 197 samples. Of the 197 specimens, 3.5% presented K-RAS codon 12 mutations. For mutated cases and non-mutated cases, complete initial response to chemoradiation therapy was 71 and 73% ( ). LRC was respectively 32 and 83% ( ), DFS was 27 and 68% ( ), distant metastasis-free survival was 100 and 81% ( ) and OS was 57 and 65% ( ) at three years. K-Ras codon 13 analysis revealed no mutation. Conclusion. K-RAS codon 12 mutational status, although not associated with a difference in response rate, may influence the failure pattern and the type of therapy offered to patients with HNSCC. Our study did not reveal any mutation of K-RAS codon 13. 1. Introduction Head and neck squamous cell carcinoma (HNSCC) accounts for 47?000 new malignancies diagnosed each year in the USA and is the sixth most common human neoplasm, representing about 3% of all cancers [1]. Despite efforts to improve conventional treatment, survival rates for these cancers have not changed significantly over the past decade. Initial evaluation of patients includes clinical assessment, study of tumor histological characteristics and tumor grading, as well as local-regional and distant metastasis status. Traditional clinical, radiological, and histopathological characteristics are however limited in their ability to accurately predict response to treatment. This has motivated many researchers to identify molecular characteristics that may influence overall prognosis. A recent interest in molecular biology and genetics is motivated by the belief that understanding the origins of cancer can lead to more logical means of treating malignancies [2]. Identification of molecular events that lead to HNSCC may represent a key to predicting biological behaviour and may consequently lead to new treatment modalities that could lead to increases in survival rates. [3, 4]. Despite the recent progress in the field of molecular biology, clinicians need more tools to predict response to therapy or to identify patients at high risk of
Synthesis, Permeability and Microstructure of the Optimal Nickel-Zinc Ferrites by Sol-Gel Route  [PDF]
S. ZAHI
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2010, DOI: 10.4236/jemaa.2010.21009
Abstract: The optimum ferrite can be obtained through free-microstructural defects where such defects are always encountered in the conventional ferrites often caused by chemical inhomogeneity. In this study, Ni-Zn ferrite was synthesized and fabricated by means of a sol-gel route. Thermal gravimetric analysis (TGA) was used to study the thermal transforma-tion of the ferrite in air. Parts of the sol-gel powder heated at elevated temperatures were characterized by X-ray dif-fraction (XRD) method and Scanning Electron Microscopy (SEM) to reveal the crystallized single-phase and the struc-ture of the obtained ferrite. Fourier transform infrared spectroscopy (FT-IR) was assisted to investigate the structure. The microstructures of the toroidal cores were obtained at two different sintering temperatures and compared with those obtained via the classic method. In addition to that, the magnetic properties were measured. The initial magnetic permeability was found to increase with the increasing of the frequency as a result of the domain wall motions and the corresponding loss was small. Therefore, a well defined polycrystalline microstructure ferrite via an easier preparation methodology as compared to the classic method is obtained.
Weighted decomposition in high-performance lattice-Boltzmann simulations: are some lattice sites more equal than others?
Derek Groen,David Abou Chacra,Rupert W. Nash,Jiri Jaros,Miguel O. Bernabeu,Peter V. Coveney
Computer Science , 2014,
Abstract: Obtaining a good load balance is a significant challenge in scaling up lattice-Boltzmann simulations of realistic sparse problems to the exascale. Here we analyze the effect of weighted decomposition on the performance of the HemeLB lattice-Boltzmann simulation environment, when applied to sparse domains. Prior to domain decomposition, we assign wall and in/outlet sites with increased weights which reflect their increased computational cost. We combine our weighted decomposition with a second optimization, which is to sort the lattice sites according to a space filling curve. We tested these strategies on a sparse bifurcation and very sparse aneurysm geometry, and find that using weights reduces calculation load imbalance by up to 85%, although the overall communication overhead is higher than some of our runs.
State Anxiety Is Associated with Cardiovascular Reactivity in Young, Healthy African Americans
Mildred A. Pointer,Sadiqa Yancey,Ranim Abou-Chacra,Patricia Petrusi,Sandra J. Waters,Marilyn K. McClelland
International Journal of Hypertension , 2012, DOI: 10.1155/2012/268013
Abstract: Although several studies have shown that enhanced cardiovascular reactivity can predict hypertension development in African Americans, these findings have not been consistent among all studies examining reactivity and hypertension susceptibility. This inconsistency may be explained by the influence of anxiety (state and trait) on the blood pressure response to stress. Therefore, this study sought to determine whether anxiety is associated with blood pressure response to cold pressor (CP) and anger recall (AR) stress tests in young healthy African Americans. Modeling using state and trait anxiety revealed that state anxiety predicts systolic (SBP) and diastolic blood pressure DBP response to CP and AR (≤0.02). Interestingly, state anxiety predicted heart rate changes only to CP (<0.01; =0.3 for AR). Although trait anxiety was associated with SBP response to AR and not CP, it was not a significant predictor of reactivity in our models. We conclude that anxiety levels may contribute to the variable blood pressure response to acute stressors and, therefore, should be assessed when performing cardiovascular reactivity measures.
State Anxiety Is Associated with Cardiovascular Reactivity in Young, Healthy African Americans
Mildred A. Pointer,Sadiqa Yancey,Ranim Abou-Chacra,Patricia Petrusi,Sandra J. Waters,Marilyn K. McClelland
International Journal of Hypertension , 2012, DOI: 10.1155/2012/268013
Abstract: Although several studies have shown that enhanced cardiovascular reactivity can predict hypertension development in African Americans, these findings have not been consistent among all studies examining reactivity and hypertension susceptibility. This inconsistency may be explained by the influence of anxiety (state and trait) on the blood pressure response to stress. Therefore, this study sought to determine whether anxiety is associated with blood pressure response to cold pressor (CP) and anger recall (AR) stress tests in young healthy African Americans. Modeling using state and trait anxiety revealed that state anxiety predicts systolic (SBP) and diastolic blood pressure DBP response to CP and AR ( ). Interestingly, state anxiety predicted heart rate changes only to CP ( ; for AR). Although trait anxiety was associated with SBP response to AR and not CP, it was not a significant predictor of reactivity in our models. We conclude that anxiety levels may contribute to the variable blood pressure response to acute stressors and, therefore, should be assessed when performing cardiovascular reactivity measures. 1. Introduction Although enhanced cardiovascular reactivity is generally associated with future development of hypertension and other cardiovascular events [1–5], there are studies that have failed to show any relationship between reactivity to stress and future elevation of blood pressure [1, 6–12]. The reason for these inconsistent findings is unclear. Emerging evidence suggest that some stress tests may be better predictors of future cardiovascular events than other stressors [4, 5, 10]. For example, blood pressure response to arithmetic and star tracing stress tests predicted high blood pressure while reactivity to cold pressor stress test did not [13, 14]. Furthermore, metanalysis of studies that assessed mental stress tests and hypertension development revealed variable success of mental tests in predicting hypertension. Among the different types of mental stressors, cognitive mental stressors were more consistent in predicting hypertension compared to emotion evoking, interview, and public speaking stressors [10]. The inconsistencies in prediction do not appear to be explained by differences in the type (mental, physical, or psychophysical) of stress tests for there is inconsistent predictability even among the types of stressors. Another possible explanation for the inconsistencies in reactivity prediction of adverse cardiovascular outcomes is the interaction of psychosocial factors with cardiovascular responses to acute laboratory
Disease Cycle, Development and Management of Sclerotinia Stem Rot of Potato  [PDF]
Dennis A. Johnson, Zahi K. Atallah
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.525388
Abstract:
Potato is severely affected by Sclerotinia sclerotiorum in the US Pacific Northwest (PNW) and satisfactory disease management has not been achieved until recently. Recent research has given a better understanding of key epidemiological factors which has resulted in improved disease management in the PNW. This work reviews the epidemiology of Sclerotinia stem rot and highlights information that has led to the better management of the disease on potato. The primary source of inoculum of Sclerotinia sclerotiorum for potato in the Columbia Basin of the PNW are ascospores produced within potato fields or carried by wind currents from neighboring fields planted to winter cereals or other crops. Ascospores are ejected from apothecia and disseminated throughout the Columbia Basin over an extended time period. Immature apothecia generally first emerge at or shortly after row closure in potato fields in the Columbia Basin. Ascospores of S. sclerotiorum are incapable of direct infection of intact green potato tissues, and flower blossoms are crucial for infection and development of the disease in potato. Airborne ascospores are deposited on open potato blossoms still attached to the canopy. Infested flowers fall and are trapped on stems, usually leaf axils, or fall on the ground, and fungal mycelia then rapidly colonize the blossoms when humidity is high in the plant canopy. Ascospores are also deposited on senescent and dead plant material on the ground, germinate, and produce mycelium. Infection occurs shortly after contaminated blossoms become lodged on stems in the plant canopy, or after stems come in contact with contaminated fallen blossoms or decomposing plant tissues on the ground. Infection can occur within 3 days after contact of contaminated blossoms with green tissue. Lesions initially appear on potato stems 14 to 30 days after row closure and 12 to 20 days following full bloom of primary inflorescences of potato in the Columbia Basin. Significant levels of outcrossing sexual recombination have been found in the homothallic S. sclerotiorum population in the Pacific Northwest. Sclerotinia stem rot of potato is best managed by using an integrated approach of combining cultural practices that produce optimum plant foliar development without producing an excessive crop canopy, irrigation management to avoid excessive amounts of irrigation water, and timely applications of fungicides. Contaminated flower blossoms served as a bridge for infection and fungicides applied
Regularization of a unilateral obstacle problem on the boundary
A. Addou,J. Zahi
International Journal of Mathematics and Mathematical Sciences , 2003, DOI: 10.1155/s0161171203110319
Abstract: We give a regularization method for a unilateral obstacle problem with obstacle on the boundary and second member f.
Osteopetrosis, Hypophosphatemia, and Phosphaturia in a Young Man: A Case Presentation and Differential Diagnosis
Zahi Mitri,Vin Tangpricha
Case Reports in Endocrinology , 2012, DOI: 10.1155/2012/238364
Abstract: We report the case of a 30-year-old African-American male with osteopetrosis and hypophosphatemia, presenting with diffuse myalgias. Laboratory evaluation performed revealed a low serum phosphorus level with urinary phosphate wasting, low calcium, and 25-hydroxyvitamin D concentrations, as well as elevated alkaline phosphatase. Skull and pelvic radiographs revealed high bone density consistent with high bone mass found on bone mineral density reports. PHEX gene mutation analysis was negative. Patient was started on calcium and phosphorus replacement, and he clinically improved. This paper will review the different subtypes of osteopetrosis, and the evaluation of hypophosphatemia.
Dynamic Personalization in Component-Based Application
Zahi Jarir,Mohammed Erradi
Asian Journal of Information Technology , 2012,
Abstract: Service personalization is an important issue in software applications. It consists in providing the capabilities to accommodate applications to the user`s requirements and preferences such as technological restrictions, mobility requirements, resources constraints, etc. To perform such personalization, users need to have flexible applications that are easily configurable and/or adaptable even in runtime. In this paper we present our experiment to ensure a dynamic and advanced personalization in component-based applications. We first elaborate a fine grain taxonomy showing the variety of applications personalization. Based on this taxonomy, we remark that it is interesting to tackle this concept at the middleware level rather than the applications level. To validate our approach, we have set up an architecture to personalize applications using the Enterprise JavaBeans technology.
Managing organizational change: Decision’s maker perceptions in the UAE manufacturing industry
Yazeen, Zahi,Okour, Adnan
International Journal of Research Studies in Management , 2012,
Abstract: This paper aims to examine the common practices of change projects in the manufacturing industry in UAE and the key factors for effective implementation and highlighting the roadblocks of organizational change. The primary data were collected through pre-interview questionnaires and analyzed using Multivariate Analysis of Variance (MANOVA). The findings revealed that technology change is the change most practiced by the UAE manufacturing industry, then strategy development, TQM driven change, and software development with less emphases on cultural change. The usable data were restively small (n=150). Further research could be done with a larger sample to test the findings. The paper offers rare insight into change management practices in the manufacturing industry in UAE in addition to the initiators’ perception of key factors of effectiveness or the roadblocks of organizational.
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