课程文献中心 更多>>

关键词： 磁共振成像   扩散张量成像   腰骶丛   脊神经根  

摘要： 目的 探讨不同b值及扩散敏感梯度方向数(MPGs)对3.0T MR腰骶神经扩散张量成像(DTI)图像质量的影响,优化成像参数.方法 分别选用不同b值(600 s/mm2、800 s/mm2)和不同MPGs(15、32)对30例健康志愿者行腰骶神经DTI扫描并建立纤维示踪成像图像,在不同b值及不同MPGs条件下分析比较图像信噪比(SNR)、对比噪声比(CNR)以及纤维示踪成像图像的质量.结果 b=600 s/mm2、MPGs=15或b=600 s/mm2、MPGs=32或b=800 s/mm2、MPGs=323组之间图像SNR无统计学差异(P>0.05),b=800 s/mm2、MPGs=15组与其余3组之间图像SNR均有统计学差异(P<0.05);b=800 s/mm2、MPGs=15组与其余3组之间图像CNR均有统计学差异(P<0.05),b=600 s/mm2、MPGs=15组与b=800 s/mm2、MPGs=32组之间图像CNR有统计学差异(P<0.05),b=600 s/mm2、MPGs=32组与b=600 s/mm2、MPGs=15组及b=800 s/mm2、MPGs=32组之间图像CNR无统计学差异;纤维示踪成像图像质量主观评分除b=600 s/mm2、MPGs=32与b=800 s/mm2、MPGs=32组间无统计学差异(P>0.05)外,其余各组两两比较均有统计学差异(P<0.05);相同b值条件下,随着MPGs增加,SNR、CNR及纤维示踪成像图像质量主观评分有增加趋势.结论 3.0T MR腰骶神经DTI参数选择b=600 s/mm2、MPGs=15时,扫描时间较短且可获得较理想的腰骶神经图像.

关键词： 双缝干涉   单缝衍射   光强度   缺级  

摘要： 杨氏双缝干涉是波动光学的基础,在波动光学的教学中具有重要地位.本单元要结合演示实验进行教学,并且,既要重点介绍两束相干光的叠加及其形成明暗条纹的空间分布和相关的定量计算,又要适当地、定性地指出条纹强度的空间变化规律及其原因.如果遇到缺级现象,也要给予一定的关注.

关键词： Oxide materials   Sputter deposition   XANES   Bonding structure  

摘要： The bonding structure of tin oxide (SnOx) films grown by reactive DC magnetron sputtering has been studied by the combination of X-ray diffraction (XRD) and soft X-ray absorption near-edge structure (XANES). The oxygen incorporation in the films has been controlled by the O2 partial pressure (PO2) in the O2/Ar discharge mixture. In addition, the impact of substrate heating and post-deposition flash lamp annealing (FLA) on crystal growth has been studied. In general, it has been stablished a transition from SnO to SnO2 arrangements by increasing PO2, where XRD and XANES provide complementary results about the formation of single- and mixed-phase films. In samples produced at room temperature, XANES gives unique information about such structural evolution, as well as related to defects like the incorporation of O2 molecules at high PO2. FLA on samples grown at room temperature promotes crystal growth and the phase evolution follows the initial structural selectivity. Finally, the optical properties and surface morphology of the films have been correlated with the structural identification. (c) 2022 The Author(s). Published by Elsevier B.V. CC_BY_NC_ND_4.0

摘要： Objective: To assess the knowledge and attitude toward epilepsy among the final and semi-final years medical students at University of ***: Despite the high prevalence of epilepsy, studies in several countries showed that students have misconceptions concerning the disease and some doctors consider their training in medical schools regarding epilepsy care to be ***/Methods: An observational cross-sectional study was carried out at College of Medicine, University of Bahri. Self-administered questionnaires were applied to 228 medical students in the final and semi-final years in March ***: Sixty-three percent of students showed a high level of knowledge. Despite that, 10.1% of the students do not know that atonic seizure is a type of epilepsy, 62.7% attributed the causes of epilepsy to psychological factors only, and 9.6% considered epilepsy is an untreatable disease. The majority of students (72.4%) are not aware that screaming is a manifestation of certain types of epilepsy. More than half of the students considered inserting something into the patient’s mouth during the seizure will prevent tongue biting. A total of 8.3% of students thought that it is a demonic attack, whereas 34.6% of students thought the Holy Quran appropriate treatment for epilepsy (p=0.026). Up to 77% of the students showed a positive attitude toward patients with epilepsy. However, 42.1% of students agreed that there should be some restrictions in sport and leisure activities for people who suffer from epilepsy, and 13.6% of students admitted they will not get married to epileptic ***: Our study showed an overall relatively high level of knowledge toward epilepsy and positive attitude toward epileptic patients. However, there are still misconceptions in different aspects. The medical schools should focus on increase the knowledge and understanding of epilepsy, not just the scientific knowledge but also discuss the social impact of epilepsy on