Enforcing Imprecise Constraints on Generative Adversarial Networks for Emulating Physical Systems

Generative adversarial networks (GANs) were initially proposed to generate images by learning from a large number of samples. Recently, GANs have been used to emulate complex physical systems such as turbulent flows. However, a critical question must be answered before GANs can be considered trusted emulators for physical systems: do GANs-generated samples conform to the various physical constraints? These include both deterministic constraints (e.g., conservation laws) and statistical constraints (e.g., energy spectrum of turbulent flows). The latter have been studied in a companion paper (Wu et al., Enforcing statistical constraints in generative adversarial networks for modeling chaotic dynamical systems. Journal of Computational Physics. 406, 109209, 2020). In the present work, we enforce deterministic yet imprecise constraints on GANs by incorporating them into the loss function of the generator. We evaluate the performance of physics-constrained GANs on two representative tasks with geometrical constraints (generating points on circles) and differential constraints (generating divergence-free flow velocity fields), respectively. In both cases, the constrained GANs produced samples that conform to the underlying constraints rather accurately, even though the constraints are only enforced up to a specified interval. More importantly, the imposed constraints significantly accelerate the convergence and improve the robustness in the training, indicating that they serve as a physics-based regularization. These improvements are noteworthy, as the convergence and robustness are two well-known obstacles in the training of GANs.     

中国9个长寿地区65岁及以上人群血铅浓度与认知功能受损的关联研究

目的探讨65岁及以上人群血铅水平与认知功能受损的关联。方法研究对象来自2017-2018年在我国9个长寿地区开展的“老年健康生物标志物队列研究”,最终将1684名血铅和认知功能数据完整的65岁及以上人群纳入本研究。通过问卷调查和体格检测,收集调查对象的人口学特征、生活方式、健康状况及认知功能评分等信息;同时采集调查对象的静脉血以检测血铅水平。根据血铅水平的四分位数将调查对象分为4组(Q₁-Q₄组),采用多因素logistic回归模型分析血铅浓度与认知功能受损的关系,采用限制性三次样条检验血铅浓度与认知受损之间是否存在非线性关联。结果1684名研究对象年龄为(83.1±11.1)岁,其中女性843名(50.1%);认知功能受损者191名(11.3%)。调整相关混杂因素后,老年人血铅浓度每升高10μg/L,认知功能受损患病风险OR(95%CI)值为1.05(1.01~1.10);与血铅浓度Q1组老年人相比,血铅浓度较高者认知功能受损的患病风险较高,Q₂,Q₃,Q₄组的OR(95%CI)值分别为1.19(0.69~2.05)、1.45(0.84~2.51)和1.92(1.13~3.27)。结论我国9个长寿地区65岁及以上老年人血铅水平与认知功能受损患病风险存在关联。     

2015—2019年四川省流感哨点监测结果分析

目的 描述四川省2015—2019年流感病毒流行特征,为疫情防控提供依据。方法 对流感监测系统上报的流感样病例数据开展回顾性流行病学分析。结果 2015—2019年间,四川省共监测流感样病例标本131 477份,其中阳性标本23 844份,流感阳性率为18.14%。2015—2019年四川省优势流感亚型主要为甲型H1N1,季节性H3N2和B(Victoria)系流感。流感阳性率随月份、季节而改变,四川省流感阳性率高峰主要出现在冬季,其次为秋季。甲型流感主要在秋冬季流行,乙型流感主要在冬春季流行。流感病毒阳性检出率在5～14岁组年龄段最高。结论 四川省流感有明显的冬季流行高峰,各型别呈交替流行。秋冬季应加强流感防控工作;甲型和乙型流感好发于5～14岁群体,应继续加强对儿童学生流感的防控。     

猪链球菌引起人中毒性休克综合征和脑膜脑炎的流行病学调查及病原学研究

目的 本研究拟本明1998年华东地区一种与病死猪有接触史的人的急性传染病病原体的生物学特征与疾病流行的关系。方法 流行病学调查,并对病死猪及死亡患者进行病理检查,分离病原及其实验研究。结果 该病具有起病急、病情重、病程短、病死率高等特点。临床及病理表现为：起病多似感冒有高热、四肢疼痛、有时有呕吐、腹泻等,迅速发展为肌炎、筋膜炎、DIC、多脏器功能衰竭、休克,多于2～3d内死亡。25例患者中,临床表现为中毒性休克综合征的16例,链球菌性脑膜脑炎综合征的9例,两者的病死率分别为81.25%和11.11%。从猪和病人标本分离的病原体,其形态、生染色性、生物学特征均一致。结论 患者血和病猪脏器中分离的病原菌鉴定结果证明两者均为链球菌。     

琼脂糖微囊化成猪胰岛异种移植实验研究

目的观察实验性糖尿病大鼠腹腔内移植琼脂糖微囊化成猪胰岛治疗效果。方法以琼脂糖作为制备微囊的材料,用相分离方法包被成猪胰岛,将18只糖尿病大鼠随机分为3组对照组、未微囊化胰岛移植组、微囊化胰岛移植组,分别进行腹腔内胰岛移植。结果移植前3组血糖水平无显著差异,移植后7天时,3组血糖分别为(22.67±1.15)mmol／L,(18.58±2.62)mmol／L和(12.38±2.68)mmol/L,微囊化胰岛移植组与前2组相比均有显著差异,且生存期明显长于前2组。结论琼脂糖微囊化成猪胰岛可存活于糖尿病大鼠体内,并且具有生物活性。     

黄芪灯盏花注射液对阳气虚型冠心病心率变异的影响

观察黄芪灯盏花注射液对 2 5例阳气虚型冠心病患者的心率变异性(HRV)的影响 ,并设对照组及正常人组 ,采用动态心电图含有 HRV时域分析软件进行分析。结果 :黄芪灯盏花注射液组 HRV数值明显提高 ,差异显著 (P<0 .0 5 ) ,或非常显著 (P<0 .0 1)。提示 :黄芪灯盏花注射液对冠心病患者 HRV心脏自主神经功能具有益影响。     

脑梗塞患者治疗时间延误原因及对策

为探讨脑梗塞患者治疗时间的延误原因和对策,对河北、内蒙古部分地区脑梗塞患者治疗时间延误的原因进行了调查分析。共调查了脑梗塞患者１０４８例,在６小时内接受治疗的人数为３２６例,占３１．１１％;在２４小时内,接受治疗的人数为５６６例,占５４．０１％;在２５小时后,接受治疗的人数为４８２例,占４５．９９％。脑梗塞患者治疗延误时间为２３．５５小时,其院前的延误时间为２１．４９小时,占９１．２５％,院后的延误时间为２．０６小时,占８．７５％。调查发现,对脑梗塞患者实施早期治疗,必须在社区内进一步加强脑梗塞症状学和及早诊治意义的科普教育;提高医务人员对脑梗塞诊治水平和治疗紧迫性的认识,建立和完善医院的快速反应系统。只有这样,脑梗塞的早期治疗,才会有根本性的改善     

动物组织中羟脯氨酸测定方法的建立及初步应用

目的：建立动物组织中的羟脯氨酸测定方法,以之估计胶原含量并衡量组织愈合程度。方法：研究显色温度、氧化时间、样品中盐浓度以及对 二甲氨基苯甲醛（ Ｐ Ｄ Ａ Ｂ） 浓度对羟脯氨酸测定的影响,据此建立动物组织中的羟脯氨酸测定方法,并初步应用于实验动物犬贲门胶原含量的测定。结果：根据优化的实验结果,羟脯氨酸测定的条件为室温氧化４ ｍｉｎ ,１０ ％ Ｐ Ｄ Ａ Ｂ,１００ ℃显色２ ｍｉｎ 。该法回收率为９８ ％ ,变异系数为４ ％ 。结论：该法重复性好,可信度高,可作为临床判定愈合程度的一个定量指标。     

Cation channel control of neurite morphology

The development of neuronal polarity and morphology is essential for a functioning nervous system. The present study was undertaken to explore whether blockade of specific channels alter neuronal morphology. Retinal ganglion cells were cultured in the presence of antagonists to NMDA, AMPA/kainate, L-, N-, P-, and Q-type voltage-dependent calcium channels (VDCCs). Five parameters were measured under these conditions: the number of neurites at the cell body, total neurite length, the length of the longest neurite, the number of branch points per neurite, and the diameter of the cell soma. Antagonists to NMDA and L-type VDCCs reduce the number of neurites at the cell body; antagonists to P- and Q-type VDCCs increase the number of neurites. Antagonists to the N-type VDCCs increase total neurite outgrowth, while antagonists to the NMDA and P-type channels reduce total neurite length. Antagonists to the NMDA and L-type channels increase the length of a single neurite, while decreasing the number of branch points; antagonists to the P- and Q-type VDCCs do essentially the opposite-increase the number of neurites, while decreasing the length of each. Blockade of one or more cation channels in developing retinal ganglion cells significantly perturbs neurite morphology. This study may help elucidate part of the role that cation channel signaling plays in neuritic development.     

粒细胞集落刺激因子对顺铂对卵巢癌细胞的细胞毒作用的影响

目的　了解粒细胞集落刺激因子（Ｇ－ ＣＳＦ）对顺铂对卵巢癌细胞的细胞毒作用的影响;方法　采用ＸＴＴ 比色法检测不同浓度顺铂对卵巢癌细胞株ＳＫＯＶ３、３ＡＯ 细胞生长影响;以及５０ ｍｇ／Ｌ 顺铂分别与不同浓度Ｇ－ ＣＳＦ 共同使用对ＳＫＯＶ３、３ＡＯ细胞生长的影响。结果　５０ ｍｇ／Ｌ 顺铂单独使用和与不同浓度Ｇ－ ＣＳＦ 共同使用２４ ｈ 对ＳＫＯＶ３、３ＡＯ 细胞生长的影响无显著性差异。结论　Ｇ－ ＣＳＦ 对顺铂对ＳＫＯＶ３、３ＡＯ 细胞的细胞毒作用无显著影响。