Evaluation of a deep learning model on coronary CT angiography for automatic stenosis detection

PurposeThe purpose of this study was to evaluate a deep-learning model (DLM) for classifying coronary arteries on coronary computed tomography -angiography (CCTA) using the Coronary Artery Disease-Reporting and Data System (CAD-RADS).Materials and methodsThe DLM was trained with 10,800 curved multiplanar reformatted (cMPR) CCTA images classified by an expert radiologist using the CAD-RADS. For each of the three main coronary arteries, nine cMPR images 40° apart acquired around each arterial circumference were then classified by the DLM using the highest probability. For the validation set composed of 159 arteries from 53 consecutive patients, the images were read by two senior and two junior readers; consensus of the two seniors was the reference standard. With the DLM, the majority vote for the nine images was used to classify each artery. Three groups (CAD-RADS 0, 1–2, or 3–4–5) and 2 groups CAD-RADS 0–1–2 or 3–4–5 (<50% vs. ≥50% stenosis) were used for comparisons with readers and consensus. Performance of the model and readers was compared to the consensus reading using the intraclass coefficient (ICC) and Cohen's kappa coefficient at the artery and patient levels.ResultsWith the three groups at the artery level, the ICC of the DLM was 0.82 (95% CI: 0.75–0.88) and not significantly different from those of 3/4 readers; accuracy was 81%. With the binary classification, Cohen kappa coefficient of the DLM was 0.85 (95% CI: 0.69–0.94) and not significantly different from that of 3/4 readers; accuracy was 96%. At the patient level, sensitivity and specificity were 93% and 97% respectively, and the negative predictive value was 97%.ConclusionThe DLM detected ≥50% stenoses with performances similar to those achieved by senior radiologists.     

Modulators of DNA methylation and histone acetylation

The distribution of epigenetic alterations, such as DNA methylation and histone modifications, is abnormal in cancer cells, and drugs that influence these changes are currently being used effectively in the treatment of hematopoietic malignancies. Two hypomethylating agents, 5-azacytidine and decitabine, are FDA-approved for the treatment of myelodysplastic syndromes, and one histone deacetylase inhibitor, vorinostat, was recently FDA-approved for patients with refractory cutaneous T-cell lymphoma. Generally, these agents are very well tolerated, with myelosuppression being the major side effect. Although they are thought to work by re-organizing chromatin to allow expression of genes silenced by DNA hypermethylation and repressive histone modifications, the precise mechanism of action of these agents is not yet clear. Current studies are examining the utility of these agents for the treatment of solid tumors as well as testing these drugs in combination to treat a variety of malignancies.     

Analysis of the Surface Ozone During Summer and Autumn at a Coastal Site in East China

The levels and temporal variations of surface ozone at a coastal site in East China during summer and autumn were analyzed and the influences of meteorological parameters on ozone were investigated. An inland city was chosen as a comparison site. The main results and conclusions of this study are: (1) ozone pollution, with a maximum 1 h concentration of 150.98 ppbv, was severe during summer and autumn at the coastal site; (2) the ozone level was obviously higher at the coastal site than that at the inland site in September; (3) besides temperature and solar radiation, sea-land breeze circulation is an important factor influencing the ozone level at the coastal site, and sea breeze often induce high ozone levels (the average ozone concentration for sea breeze was about 13 ppbv higher than that for land breeze).     

出血性蛇毒诱导血管内皮细胞凋亡的成分及作用机制研究进展

出血性蛇毒能专一性诱导血管内皮细胞(vascular endothelial cells，VEC)凋亡，研究人员已从中分离出5种VEC凋亡诱导成份，其中2种为L—aa氧化酶类，3种属于金属蛋白酶／解整联蛋白家族。研究证实前者可通过氧化VEC细胞膜上的L—leu产生H2O2而诱导其凋亡，后者则通过干扰膜整联蛋白与其配体的结合而使VEC凋亡。在由蛇毒诱导的VEC凋亡过程中，p53和bcl-2基因表达增加，且bcl-2的mRNA被剪辑成2条。已证实锚定依赖性信号分子αvβ3和磷脂信号分子PC-PLC参与该过程的信号转导。对该领域进一步研究，有望从蛇毒中纯化出或人工构建出专一地诱导肿瘤血管细胞凋亡的成分。本文总结了出血性蛇毒方面的研究进展。     

乳酸菌Z222产胞外多糖(EPSⅠ)对免疫细胞功能的影响

目的　检测乳酸菌Z2 2 2 产胞外多糖EPSⅠ对体外免疫细胞功能的调节作用。方法　不同浓度的EPSⅠ作用于小鼠的腹腔巨噬细胞和脾细胞 ,分别用中性红染色法检测巨噬细胞的吞噬能力 ,用MTT法检测淋巴细胞在体外的转化能力、NK细胞杀伤肿瘤细胞Yac 1的能力和产细胞因子IL 2的活性。结果　 (1)EPSⅠ单独作用小鼠脾细胞就能促进体外淋巴细胞增殖 ,且表现出剂量依赖关系。EPSⅠ亦可促进ConA诱导的体外小鼠淋巴细胞转化。 (2 )EPSⅠ体外作用于小鼠腹腔巨噬细胞均可提高MΦ的吞噬能力 ,与对照组比较差异都有显著性。 (3)与对照组相比EPSⅠ能增加体外NK细胞的活性 ,杀伤率最大值达 6 2 .4 1%± 2 .5 4 %。 (4 )EPSⅠ使小鼠脾细胞产IL 2的能力与对照组比较 ,差异有显著性。结论　乳酸菌多糖EPSⅠ对小鼠的免疫功能有一定的调节作用。     

云南省19县市小兽体表蚤类的生态位研究

对云南省19县市小兽体表蚤类生态位进行研究,并初步探讨两者间协同进化关系。采用Levins模型和Cowell-Futuymas模型分别测定47种小兽体表部分主要蚤种的生态位宽度和生态位重叠指数。生态位宽度最宽的是特新蚤（0.0987）,其次是近端远棒蚤二刺亚种（0.0749）、低地狭臀蚤（0.0734）,最窄的为伍氏病蚤（0.0216）。方叶栉眼蚤与近端远棒蚤二刺亚种生态位重叠指数最高（0.5）,与伍氏病蚤的重叠指数最低（0.0021）。印鼠客蚤与缓慢细蚤生态位重叠指数最高（0.8660）,与无值大锥蚤最低（0.0048）。蚤类生态位宽度值低,表明其与宿主动物之间的协同进化程度相对较高;生态位宽度值高,表明其与宿主动物之间的协同进化程度较低。两种蚤的生态位重叠值高,表明其在宿主选择上趋于相同或相近;反之,则差异较大。生态位宽度可以作为蚤类与其宿主动物间协同进化的一个判定指标。     

基于3D Shepp-Logan头部模型的三维医学图像重建仿真

Shepp-Logan头部模型是计算机断层图像重建(CT)领域仿真计算普遍采用的经典模型。我们提出一种新思路—以3D Shepp-Logan头部模型作为三维医学图像重建领域进行仿真实验和算法性能评测的基本参考模型。首先介绍了3D Shepp-Logan头部模型的设计与实现以及仿真投影数据的计算,进而描述了所设计的三维医学图像重建仿真计算过程。数值实验部分给出了基于3D Shepp-Logan头部模型的三维医学图像重建仿真实验。实验结果表明了新思路的可行性和模型计算的准确性。     

水飞蓟宾构象的理论研究

目的 水飞蓟宾RRRR对映体分子中存在多个可变的二面角，可以产生许多立体构象，旨在从理论上寻找其合理构象。方法 采用二面角系统搜索后，结合AM1方法确定主要构象，以B3LYP／6—31G*方法优化构型后，在B3LYP／3—21G水平计算了振动频率和热力学参数。结果 得到了各二面角的分布情况，找出了主要的局部构象，明确了C9-C11和C18-C22旋转主要引起分子构象变化，4种主要构象能量差异较小，都有存在的可能性，二面角C19-C18-C22-C32和C8-C9-C11-C16变化的能量曲线表明，C9-C11旋转的能垒很小，受C19的羟甲基影响，C18-C22旋转能垒较大。结论 水飞蓟宾RRRR对映体主要以4种构象的形式存在。     

高等学校不同经营类型食堂饮食卫生状况

目的了解和掌握高等学校内不同经营类型食堂的饮食卫生管理状况,为进一步做好高校饮食卫生管理提供对策。方法对高校分别由学校经营、承租经营和个体经营的15个食堂或餐厅、40名从业人员进行现场检查和评分,并对检查结果进行综合分析。结果不同经营类型的食堂饮食卫生状况差异有统计学意义(P<0.05);不同经营类型食堂从业人员的卫生状况差异有统计学意义(P<0.05);不同经营类型的食堂饮食卫生管理的各监督环节平均得分不同。结论高校内学校经营管理的食堂卫生管理较好,承租、个体经营的餐厅或食堂在饮食卫生管理方面存在较多的安全隐患。