نتایج جستجو برای: r50
تعداد نتایج: 179 فیلتر نتایج به سال:
Recent standard dosimetry protocols recommend that plane-parallel ionization chambers be used in the measurements of depth-dose distributions or the calibration of low-energy electron beams with beam quality R50 <4 g/cm2. In electron dosimetry protocols with the plane-parallel chambers, the wall correction factor, Pwall, in water is assumed to be unity and the replacement correction factor, Pre...
PURPOSE To provide a comprehensive investigation of electron beam reference dosimetry using Monte Carlo simulations of the response of 10 plane-parallel and 18 cylindrical ion chamber types. Specific emphasis is placed on the determination of the optimal shift of the chambers' effective point of measurement (EPOM) and beam quality conversion factors. METHODS The EGSnrc system is used for calc...
Appropriate management of crop residue plays a key role in mitigating greenhouse gas emissions. However, it has been inadequately implemented general agricultural practices. In field investigation using static chambers, we evaluated the effects at three different rates - 100 % (R100), 50 (R50), and removal (R0) on carbon dioxide (CO2) efflux. The study was conducted corn-wheat rotation under co...
The aims of this study were to develop and validate a prediction equation of fat-free mass (FFM) based on bioelectrical impedance analysis (BIA) and anthropometry using air-displacement plethysmography (ADP) as a reference in Asian neonates and to test the applicability of the prediction equations in an independent Western cohort. A total of 173 neonates at birth and 140 at two weeks of age wer...
Hemorrhages in the retinal fundus are a common symptom of both diabetic retinopathy and macular edema, making their detection crucial for early diagnosis treatment. For this task, aim is to evaluate performance two pre-trained additionally fine-tuned models from Detectron2 model zoo, Faster R-CNN (R50-FPN) Mask (R50-FPN). Experiments show that provides highly accurate segmentation masks each de...
Glucose 6-Phosphate Dehydrogenases (G6PDHs) from different sources show varying specificities towards NAD+ and NADP+ as cofactors. However, it is not known to what extent structural determinants of cofactor preference are conserved in the G6PDH family. In this work, molecular simulations, kinetic characterization of site-directed mutants and phylogenetic analyses were used to study the structur...
PURPOSE To reduce the potential of late toxicity (tissue necrosis and cognitive function loss) from brain radiotherapy, we studied a novel planning technique for MLC-equipped linear accelerators (LINACS) that reduces the high doses delivered outside the PTV, enhancing radiation dose conformity. METHODS The feasibility of improving dose conformity by using variable source-to-tumor distances wa...
The Radiation Therapy Oncology Group (RTOG) 0813 protocol requires the use of dose calculation algorithms with tissue heterogeneity corrections to compute dose on stereotactic body radiation therapy (SBRT) non-small cell lung cancer (NSCLC) plans. A new photon dose calculation algorithm called Acuros XB (AXB) has recently been implemented in the Eclipse treatment planning system (TPS). The main...
چکیده آفتابگردان یکی از گیاهان روغنی مهم در ایران است. جهت تولید هیبرید های پرمحصول آفتابگردان، نیازمند اطلاعاتی در رابطه با وراثت پذیری و ترکیب پذیری های عمومی و خصوصی لاین های مورد استفاده هستیم. به منظور بررسی ترکیب پذیری عمومی و خصوصی و اثرهای ژنی در آفتابگردان، نه لاین نرعقیم و چهار تستر به صورت لاین × تلاقی داده شدند. هیبریدهای حاصل در قالب طرح بلوک های کامل تصادفی با سه تکرار در ایستگ...
تنش خشکی یکی از عواملی است که محصول آفتابگردان (helianthus annuus l.) را در مناطق خشک و نیمه خشک جهان از جمله ایران مورد تهدید قرار می دهد. به دلیل قابلیت ذاتی آفتابگردان در تحمل خشکی، شناسائی و اصلاح ارقام پر محصول و مقاوم به تنش کمبود آب ضروری می باشد. برای گزینش ژنوتیپ های برتر از طریق روش های متداول اصلاح نباتات، درک صحیح از اساس ژنتیکی صفات درگیر در تحمل خشکی ضرورت دارد. بررسی نوع عمل ژن ه...
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