Opportunistic Spectrum Sharing using Dumb Basis Patterns: The Line-of-Sight Interference Scenario

We investigate a spectrum-sharing system with non-severely faded mutual interference links, where both the secondary-to-primary and primary-to-secondary channels have a Line-of-Sight (LoS) component. Based on a Rician model for the LoS channels, we show, analytically and numerically, that LoS interference hinders the achievable secondary user capacity. This is caused by the poor dynamic range of the interference channels fluctuations when a dominant LoS component exists. In order to improve the capacity of such system, we propose the usage of an Electronically Steerable Parasitic Array Radiator (ESPAR) antenna at the secondary terminals. An ESPAR antenna requires a single RF chain and has a reconfigurable radiation pattern that is controlled by assigning arbitrary weights to M orthonormal basis radiation patterns. By viewing these orthonormal patterns as multiple virtual dumb antennas, we randomly vary their weights over time creating artificial channel fluctuations that can perfectly eliminate the undesired impact of LoS interference. Because the proposed scheme uses a single RF chain, it is well suited for compact and low cost mobile terminals

Anticancer Activity, Antioxidant Activity, and Phenolic and Flavonoids Content of Wild Tragopogon porrifolius Plant Extracts

Tragopogon porrifolius, commonly referred to as white salsify, is an edible herb used in folk medicine to treat cancer. Samples of Tragopogon porrifolius plant grown wild in Palestine were extracted with different solvents: water, 80% ethanol, and 100% ethanol. The extracts were analyzed for their total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (AA). Four different antioxidant assays were used to evaluate AA of the extracts: two measures the reducing power of the extracts (ferric reducing antioxidant power (FRAP) and cupric reducing antioxidant power (CUPRAC)), while two other assays measure the scavenging ability of the extracts (2,2-azino-di-(3-ethylbenzothialozine-sulphonic acid (ABTS)) and 2,2-diphenyl-1-picrylhydrazyl (DPPH)). Anticancer activity of the plant extracts were also tested on HOS and KHOS osteosarcoma cell lines. The results revealed that the polarity of the extraction solvent affects the TPC, TFC, and AA. It was found that both TPC and AA are highest for plant extracted with 80% ethanol, followed by water, and finally with 100% ethanol. TFC however was the highest in the following order: 80% ethanol > 100% ethanol > water.The plant extracts showed anticancer activities against KHOS cancer cell lines; they reduced total cell count and induced cell death in a drastic manner

Egyptian Needs and the Water Resources Under the Agreements Among the Nile River Basin Countries

Abstract: Water is Egypt issue today, and its danger is increasing in the future years. Egypt is considered one of the poorest 35 countries in the world,its ownership of freshwater resources, where Egyptian citizen share in 1947year was reached about 2604 m 3 / year, it decreased over the years following that reached 860 m 3 / year in 2003, possibly the individual share will decrease to 582 m 3 / year in 2025, due to the available water resources for agriculture is limited, the future demand increasing for the purposes of horizontal and vertical expansion in cultivated area, the low efficiency of availability use of it, in addition to the obstacles in the traditional sources use, and as a result of the increase in population with demand for water is increased,and the available renewable water resources are constant, which led to increase the water problem in Egypt, Therefore, the study aimed to Identify the current available of Egyptian needs, water resources, individual share average of water, and identify the periods of abundance,scarcity and water poverty through the presentation of the various water agreements among the Nile River Basin countries, The study proved that total water needs reached about 69

Factors Affecting the Reluctance to Pursue Teaching as a Career from the Perspective of Students in the Sultanate of Oman: A mixed-approach Investigation

هدفت الدراسة الحالية إلى الكشف عن العوامل المؤثرة في عزوف الطلبة عن مهنة التدريس بسلطنة عمان. استخدمت الدراسة المنهج المختلط، حيث تم جمع البيانات الكمية من خلال مقياس العوامل المؤثرة على اختيار مهنة التدريس بعد تعريبه وتكييفه لمجتمع الدراسة المكون من طلبة الصفوف 10-12 (ن= 3455)، أما البيانات النوعية فقد تم جمعها من خلال مجموعات النقاش البؤرية مع طلبة هذه الصفوف (ن= 253). أشارت النتائج إلى أن العوامل المؤثرة في عزوف الطلبة عن مهنة التدريس تمحورت حول: صعوبة المهنة، وقلة حوافزها المادية، وتدني المكانة الاجتماعية لها مقارنة بالمهن الأخرى، بينما بينت نتائج مجموعات النقاش البؤرية وجود آراء إيجابية وسلبية للمهنة، ووجود تحديات أبرزها: صعوبة التعامل مع عدد كبير من الطلبة، وتوقف ترقيات المعلمين، وتعيين المعلمين بعيدا عن أماكن إقامتهم. كما بين أغلبية طلبة المدارس من الجنسين بأنه ليس لديهم الرغبة والاتجاه الإيجابي لاختيار التدريس كمهنة المستقبل. كما أشارت نتائج الدراسة المتعلقة بالفروق بين الجنسين إلى وجود فروق دالة إحصائيا لصالح الذكور في العزوف عن مهنة التدريس

Osteogenic Differentiation Potential of Human Bone Marrow and Amniotic Fluid-Derived Mesenchymal Stem Cells in Vitro & in Vivo

BACKGROUND: Cell therapies offer a promising potential in promoting bone regeneration. Stem cell therapy presents attractive care modality in treating degenerative conditions or tissue injuries. The rationale behind this is both the expansion potential of stem cells into a large cell population size and its differentiation abilities into a wide variety of tissue types, when given the proper stimuli. A progenitor stem cell is a promising source of cell therapy in regenerative medicine and bone tissue engineering. AIM: This study aimed to compare the osteogenic differentiation and regenerative potentials of human mesenchymal stem cells derived from human bone marrow (hBM-MSCs) or amniotic fluid (hAF-MSCs), both in vitro and in vivo studies. SUBJECTS AND METHODS: Human MSCs, used in this study, were successfully isolated from two human sources; the bone marrow (BM) and amniotic fluid (AF) collected at the gestational ages of second or third trimesters. RESULTS: The stem cells derived from amniotic fluid seemed to be the most promising type of progenitor cells for clinical applications. In a pre-clinical experiment, attempting to explore the therapeutic application of MSCs in bone regeneration, Rat lumbar spines defects were surgically created and treated with undifferentiated and osteogenically differentiated MSCs, derived from BM and second trimester AF. Cells were loaded on gel-foam scaffolds, inserted and fixed in the area of the surgical defect. X-Ray radiography follows up, and histopathological analysis was done three-four months post- operation. The transplantation of AF-MSCs or BM-MSCs into induced bony defects showed promising results. The AF-MSCs are offering a better healing effect increasing the likelihood of achieving successful spinal fusion. Some bone changes were observed in rats transplanted with osteoblasts differentiated cells but not in rats transplanted with undifferentiated MSCs. Longer observational periods are required to evaluate a true bone formation. The findings of this study suggested that the different sources; hBM-MSCs or hAF-MSCs exhibited remarkably different signature regarding the cell morphology, proliferation capacity and osteogenic differentiation potential CONCLUSIONS: AF-MSCs have a better performance in vivo bone healing than that of BM-MSCs. Hence, AF derived MSCs is highly recommended as an alternative source to BM-MSCs in bone regeneration and spine fusion surgeries. Moreover, the usage of gel-foam as a scaffold proved as an efficient cell carrier that showed bio-compatibility with cells, bio-degradability and osteoinductivity in vivo

Rheumatic tricuspid valve disease: Repair versus Replacement

Background: Tricuspid valve disease is most commonly functional, however, organic affection still accounts for one fourth of cases. Rheumatic fever which is endemic in Egypt is a main cause of organic affection. Current practice largely relies on tricuspid valve repair; however, it has been difficult to determine optimal procedure. Objectives: Herein, we study the outcome of replacement versus repair in such patients. Patients and methods: A prospective study was conducted on 300 consecutive patients with rheumatic heart disease showing severe tricuspid valve affection underwent tricuspid valve surgery, between 2014 and 2018. The patients were divided into two groups; TVR group (n=150) which included patients who underwent tricuspid valve replacement and TVr group (n=150) which included patients who underwent tricuspid valve repair. Diagnosis and follow up were done by echocardiography. Peri-operative variables, clinical outcome, morbidity, mortality, and follow up data were recorded. Results: Mean follow-up was 4±1.32 years. In-hospital mortality was 6 patients (4%) in TVR group and 3 patients (2%) in TVr group (P value ≥ 0.05). Postoperative low cardiac output syndrome and stroke were significantly higher in the repair group. Postoperative RV dysfunction, renal impairment, renal failure and chest re-exploration were significantly higher in the replacement group. Severe tricuspid regurgitation was reported in 19 patients (12.6%) of the repair group on follow up. Conclusion: Tricuspid valve repair is preferable to replacement to avoid the drawbacks of prosthesis. However, tricuspid valve replacement is feasible with comparable survival outcome and the progressive nature of the rheumatic disease may recommend replacement