Design and implementation of an electronic system for a microgravity experiment

The focus of this thesis is to design and develop a complete electronic system consisting of a heating subsystem, an acoustic wave subsystem, and an instrumentation subsystem for an experiment in microgravity. The aim of this work is to ensure the correct performance of all these subsystems in order to demonstrate that convection can be achieved using acoustic waves in microgravity conditions

ADHERENCE TO MEDITERRANEAN DIET AMONG ADOLESCENTS ATTENDING PUBLIC SCHOOLS IN NORTH LEBANON

The Mediterranean diet (MD) is a model of a healthy diet and healthy lifestyle. Adherence to the MD has been correlated with a reduction in many metabolic disorders including cancers. The factors associated with adolescents’ adherence to the MD in North Lebanon using the KIDMED index have never been explored. The objective of this study was to examine the factors associated with the Mediterranean diet (MD) adherence among a sample of Lebanese adolescents. A cross-sectional survey was conducted in the city of Tripoli, North Lebanon. A total of 298 students, aged 11-18 years, were randomly selected from public schools in the area. All participants completed a questionnaire on the Mediterranean diet (KIDMED index), physical activity (physical activity questionnaires for older children [PAQ-C] and adolescents [PAQ-A]), health-related quality of life (KIDSCREEN-27 index), and sociodemographic characteristics (age, gender, grade level, and parents’ educational status). The questionnaire was followed by anthropometric measurements. Adherence to the MD was good among only 13.4% of the adolescents. The prevalence rate of overweight and obesity was elevated reaching 36.9% of the students. Lower adherence to the MD was significantly correlated with skipping meals (P=0.004) and consuming fewer meals with the family (

Thermal transport in thin films and across interfaces

Heat dissipation is a critical bottleneck for microelectronic device performance and longevity. At micrometer and nanometer length scales heat carriers scatter at the boundaries of the material reducing its thermal conductivity. Additionally, thermal boundary conductance across dissimilar material interfaces becomes a dominant factor due to the increase in surface area relative to the volume of device layers. Therefore, techniques for monitoring spatially varying temperature profiles, and methods to improve thermal performance are critical to future device design and optimization. The first half of this thesis focused on frequency domain thermoreflectance (FDTR) to measure thermal transport in nanometer-thick polymer films and across an organic-inorganic interface. Hybrid structures of organic and inorganic materials are widely used in devices such as batteries, solar cells, transistors, and flexible electronics. The Langmuir-Blodgett (LB) technique was used to fabricate nanometer-thick polymer films ranging from 2 - 30 nm. FDTR was then used to experimentally determine the thermal boundary conductance between the polymer and solid substrates. The second half of the thesis focused on developing a fundamental understanding of thermal transport in wide-bandgap (WBG) materials, such as GaN, and ultrawide-bandgap (UWBG) materials, such as diamond, to improve thermal dissipation in power electronic devices. Improvements in WBG materials and device technologies have slowed as thermal properties limit their performance. UWBG materials can provide a dramatic leap in power electronics technologies while temporarily sidestepping the problems associated with their WBG cousins. However, for power electronic devices based on WBG- and UWBG-materials to reach their full potential the thermal dissipation issues in these hard-driven devices must be understood and solved. FDTR provides a comprehensive pathway towards fully understanding the physics governing phonon transport in WBG- and UWBG-based devices. By leveraging FDTR imaging and measuring samples as a function of temperature, defect concentration, and thickness, in conjunction with transport models, a well-founded understanding of the dominant thermal-carrier scattering mechanisms in these devices was achieved. With this knowledge we developed pathways for their mitigation

Exploration of the Risk Factors of Generalized and Central Obesity among Adolescents in North Lebanon

Adolescents’ obesity is an emerging public health problem globally and in the Arab countries. Alarming rates of overweight/obesity have been rising progressively in Lebanon. However, the risk factors for the development of adolescents’ obesity have not yet been thoroughly explored in North Lebanon. To determine the dietary and lifestyle risk factors associated with generalized and central obesity among adolescents living in Tripoli, a cross-sectional survey was conducted including a representative sample of 311 students aged 11–16 years from both sexes chosen from public and private schools in Tripoli. Data were collected using a standardized questionnaire to determine sociodemographic characteristics, dietary patterns, and physical activity and sedentary behaviors. Body mass index (BMI) was evaluated using the Center for Disease Control BMI for age percentiles. Central obesity was assessed using both waist-to-height ratio and gender-specific waist circumference for age indices. Multiple logistic regression analysis revealed that skipping breakfast and physical inactivity were the most significant independent risk factors associated with both generalized and central obesity. In addition, higher screen time and male gender were associated with increased risk for generalized and central obesity, respectively. Intervention strategies to prevent the development of obesity should be implemented among adolescent students to encourage regular breakfast intake and adopting healthy dietary and lifestyle behaviors

HEALTH-RELATED QUALITY OF LIFE AMONG ADOLESCENTS ATTENDING PRIVATE SCHOOLS IN NORTH LEBANON

Health-related quality of life (HRQoL) describes a person’s subjective evaluation of his health and well-being. The HRQoL and its associated factors have not been investigated among Lebanese adolescents. The aim of this study is to examine the association between socio-demographic characteristics, eating habits, physical activity, adherence to Mediterranean diet, and HRQoL among Lebanese adolescents. A total of 283 students (158 males, 125 females), between ages 11 to 18, were randomly chosen from private schools in the city of Tripoli, North Lebanon. Standard anthropometric measurements were taken. The participants completed questionnaires on Mediterranean diet (KIDMED), physical activity (physical activity questionnaires for older children [PAQ-C] and adolescents [PAQ-A]), and health-related quality of life (KIDSCREEN-27). Results of this study reveal that obese adolescents tend to express a poorer HRQoL. In Contrast, being physically active improves their HRQoL scores

Application of the Concept of the Knowledge Economy with the Tools of the German Economic Experience in Accordance with the Lebanese Economic Environment

Perhaps the most important thing about this study is that it is the first attempt in the Lebanese economic system to study the concept of the knowledge economy, how to apply it, and the possibility of its application in the local Lebanese economy, in addition to its application. The model of the German economic experience in light of the current economic situation and the challenges of rapid technological development.The study examines the application of the German economic experience model and knowledge economy in Lebanese economic environments, considering the opinions of institutions, companies, and economic actors.Research aims to develop a Lebanese economic model avoiding globalization’s external influences and preventing collapse.Study interviews 30 economists and administrators in Lebanon to explore the application of the German economic model and knowledge economy together.The results of the interviews were very positive, and the experts confirmed that there is a possibility to apply a large part of the factors on which the German economic experience relied, and most of these factors have been mentioned.Analysis reveals potential merger of German experience and knowledge economy techniques, with acceptance and encouragement. Priority is given to finding a new formula and proposing a detailed implementation business model

Burkitts's lymphoma - an atypical presentation.

BACKGROUND: In female adolescents and young adults, malignancies of the genital tract are the most frequent type of cancer, closely followed by Hodgkin's and non-Hodgkin's lymphomas. CASE PRESENTATION: We report an unusual case of sporadic Burkitt's lymphoma (BL) presenting with massive bilateral ovarian infiltration, peritoneal carcinomatosis and diffuse nodular lesions of the stomach and the intestine mimicking Krukenberg tumor. Diagnostic biopsies were obtained by endoscopy of the upper gastrointestinal tract. With intensive chemotherapy, complete remission was rapidly achieved, without life-threatening tumor lysis syndrome. CONCLUSION: Besides metastatic gastric adenocarcinoma, BL is an important differential diagnosis in adolescents presenting with Krukenberg tumor