新冠肺炎疫情对上海经济社会发展的影响机制与应对策略

新型冠状病毒肺炎(以下简称新冠肺炎)疫情对上海经济社会发展造成了诸多影响,上海正在深入学习贯彻习近平总书记系列重要讲话精神,坚定推进"两手抓、两手硬、两手赢"。通过电话咨询部分企业家、查阅媒体相关文献、对比SARS疫情、政策分析等方式,研究认为新冠肺炎疫情对上海经济发展的影响可以从"短期-中期-长期"的时间序列进行分析,而对社会发展影响则可从"个人-社区-城市-社会"空间序列进行探讨,在影响机制的基础上还提出了相应的对策建议。     

Reconstituted versus dry alfalfa hay in starter feed diets of Holstein dairy calves: Effects on feed intake,feeding and chewing behavior,feed preference,and health criteria

We investigated the effect of reconstitution of alfalfa hay on feeding and chewing behavior, sorting activity, and health status using 20 neonate Holstein male calves (3 d of age; 40.3 ± 1.30 kg of body weight) that were assigned randomly to 2 treatments, a starter feed containing either 10% dry (AH) or reconstituted alfalfa hay (RAH), each consisting of 10 calves. Alfalfa hay was reconstituted with water 24 h before feeding to achieve a theoretical dry mater (DM) content of 20%. Both starter diets had the same ingredients and nutrient compositions but differed in their DM content (90.9 vs. 66.6% DM for AH vs. RAH, respectively). Calves were weaned on d 50 and remained in the study until d 70. Reconstitution of alfalfa hay increased the percentage of particles retained on 8- and 1.18-mm sieves, but reduced feed materials retained on the bottom pan. Feeding RAH tended to increase meal frequency (preweaning) and increased meal duration (pre- and postweaning), and thereby increased time devoted to eating without affecting nutrient intake. Calves fed RAH tended to have lower eating rate during the pre- and postweaning periods. Tendencies to concurrent increase in rumination frequency and rumination duration in calves fed RAH increased time devoted to ruminating during the preweaning period; however, a tendency to longer rumination duration did not affect ruminating time during the postweaning period. Calves fed RAH spent less time resting and standing and more time drinking during the postweaning period. Non-nutritive oral behaviors were not affected by treatment during the pre- and postweaning period. Feeding RAH decreased sorting of particles retained on 8-mm sieve compared with AH; however, calves in both treatment groups sorted for particles retained on 8- and 1.18-mm sieves and against the feed materials retained on the bottom pan. Crude protein and neutral detergent fiber intakes of particles retained on the both 8- and 1.18-mm sieves increased in calves fed RAH versus AH, with no changes in intake of nutrients retained on the bottom pan. Calves fed AH were more susceptible to develop diarrhea (odds ratio = 2.02) and pneumonia (odds ratio = 4.74) and thereby had lower chances of being treated. We found no difference between treatment groups for frequency and medication days of diarrhea; however, calves fed RAH experienced fewer days with diarrhea. Furthermore, frequency and number of days with pneumonia and administration of medication were greater for calves fed AH compared with calves fed RAH. Blood concentrations of total protein and globulin tended to be higher in calves fed RAH compared with calves fed AH. Overall, feeding RAH increased time devoted to eating by increasing meal frequency and meal duration but did not affect feed intake due to lower eating rate. Calves in both treatment groups exhibited feed sorting at the extent to which they balanced intake of nutrients and met their nutritional needs. Calves, in general, were healthy, but it seems that feeding a diet containing reconstituted alfalfa hay has a potential health-promoting effect, possibly through reducing diet dustiness and improving immune status.     

Substituting corn silage with reconstituted forage or nonforage fiber sources in the starter feed diets of Holstein calves: Effects on intake,meal pattern,sorting, and health

We examined the effect of replacing corn silage (CS) with reconstituted alfalfa hay (RAH) or reconstituted beet pulp (RBP) in the starter diets on feeding behavior, sorting, and health criteria using 54 neonatal female Holstein calves that were assigned randomly to 3 groups receiving starter diets containing CS (10% on a dry matter basis), RAH, or RBP. The starter diets had the same nutrient composition and moisture level but differed in particle size distribution. Calves fed CS tended to have a lower intermeal interval compared with calves fed RAH before weaning; however, meal frequency and duration, eating rate, and meal size were not affected by treatment before and after weaning, which resulted in no changes in feed intake and time spent eating. Rumination frequency was higher for calves fed CS than for calves fed RAH or RBP after weaning. Feeding RBP decreased rumination duration compared with CS and RAH after weaning; however, calves fed RBP had a higher rumination bout interval compared with calves fed CS. Calves fed CS spent more time ruminating compared with calves fed RAH or RBP after weaning. Feeding CS tended to decrease and decreased time devoted to standing and lying, respectively, compared with calves fed RBP; however, calves fed RBP tended to spend more time on nonnutritive oral behaviors compared with calves fed RAH. Calves fed CS sorted against particles retained on the 8-mm sieve of the Penn State Particle Separator (PSPS) and for particles retained on the 1.18-mm sieve of the PSPS. Feeding RAH increased sorting for particles retained on the 8- and 1.18-mm sieves of the PSPS. Calves fed RBP sorted only for particles retained on the 1.18-mm sieve of the PSPS. Calves fed RBP tended to be more susceptible to developing pneumonia compared with calves fed CS or RAH; however, frequency and duration of diarrhea and pneumonia or number of days needed to medicate the diseases were unchanged across treatment groups. Initial (d 3) blood total protein concentration was similar (6.51 g/dL) across treatment groups. Overall, replacing CS with RAH or RBP did not affect time devoted to eating and feed intake due to no significant changes in meal size or intermeal interval before and after weaning. Calves showed feed sorting at the extent to which they balanced intake of nutrients and met their nutritional needs. Calves in general were healthy; therefore, CS, RAH, or RBP can be used interchangeably based on availability and competitive feed price.     

用于肺炎图像分类的优化卷积神经网络方法

目前,卷积神经网络（CNN）开始应用在肺炎分类领域。针对层数较浅、结构较为简单的卷积网络对肺炎识别的准确率难以提高的情况,采用深度学习方法,并针对采用深度学习方法时常常需要消耗大量的系统资源,导致卷积网络难以在用户端部署的问题,提出一种使用优化的卷积神经网络的分类方法。首先,根据肺炎图像的特征,选择具有良好图像分类性能的AlexNet与InceptionV3模型;然后,利用医学影像特点对层次更深、结构更加复杂的InceptionV3模型进行预训练;最后,通过知识蒸馏的方法,将训练好的"知识"（有效信息）提取到AlexNet模型中,从而实现在减少系统资源占用的同时,提高准确率的效果。实验数据表明,使用知识蒸馏后,AlexNet模型的准确率、特异性与灵敏度分别提高了4.1、7.45、1.97个百分点,且对图像处理器（GPU）占用相比InceptionV3模型减小了51个百分点。     

Differentiation between COVID‐19 and bacterial pneumonia using radiomics of chest computed tomography and clinical features

To develop and validate an effective model for distinguishing COVID‐19 from bacterial pneumonia. In the training group and internal validation group, all patients were randomly divided into a training group (n = 245) and a validation group (n = 105). The whole lung lesion on chest computed tomography (CT) was drawn as the region of interest (ROI) for each patient. Both feature selection and model construction were first performed in the training set and then further tested in the validation set with the same thresholds. Additional tests were conducted on an external multicentre cohort with 105 subjects. The diagnostic model of LightGBM showed the best performance, achieving a sensitivity of 0.941, specificity of 0.981, accuracy of 0.962 on the validation dataset. In this study, we established a differential model to distinguish between COVID‐19 and bacterial pneumonia based on chest CT radiomics and clinical indexes.     

CNAS检测和校准实验室应对“新冠疫情”的风险管理

在全国抗击新冠肺炎疫情的非常时期,随着各类企事业单位的复工复产,作为经中国合格评定国家认可委员会(CNAS)认可的检测和校准实验室应对其引起的潜在风险进行识别和应对。本文分析了实验室受"新冠疫情"影响而产生的各类风险点,通过建立风险评价矩阵,制定了应对和预防措施以减少对实验活动的不利影响,从而推进了实验室风险管理体系的优化。     

Clearance of the SARS-CoV-2 Virus in an Immunocompromised Patient Mediated by Convalescent Plasma without B-Cell Recovery

Coronavirus disease (COVID-19) is a contagious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This case report presents a patient who had difficulty eradicating the corona virus due to being treated with Rituximab, which depletes B lymphocyte cells and therefore disables the production of neutralizing antibodies. The combined use of external anti-viral agents like convalescent plasma, IVIG and Remdesivir successfully helped the patient’s immune system to eradicate the virus without B-cell population recovery. In vitro studies showed that convalescent plasma is the main agent that helped in eradicating the virus.     

左氧氟沙星在重症社区获得性肺炎患者中的药物动力学研究

目的: 比较左氧氟沙星治疗重症肺炎的不同用药方案的药物动力学差异,为临床合理用药提供依据。方法: 24例成人重症社区获得性肺炎且正在接受机械通气的患者分为两组(n=12),分别每日1次或2次静脉滴注左氧氟沙星 500 mg,同时每日滴注1次拉维酸 1 g,连续静脉滴注 10 d,经过 2 d 的治疗达到稳定状态后利用高效液相色谱法测定血浆和上皮细胞衬液中左氧氟沙星的浓度,并比较两组间药动学参数。结果: 每日滴注1次的患者,左氧氟沙星的血浆值浓度和上皮细胞衬液浓度分别为(12.6±2.3) mg/L 和(11.9±2.7) mg/L,每日滴注2次的患者分别为(19.7±1.8) mg/L 和(17.8±1.7) mg/L,这表明左氧氟沙星在肺组织的穿透率都大于100%。每日滴注1次和2次的患者全身暴露浓度(AUC_24h)分别为(151.2±12.8) mg·h·L^-1 和(208.6±15.1) mg·h·L^-1,均高于常见重症肺炎致病菌的最小抑菌浓度(MIC)。每日滴注1次组的治疗成功率为83%(10/12),每日滴注2次组为92%(11/12),无统计学差异(P>0.05)。结论: 对因重症社区获得性肺炎接受机械通气的危重患者,每日静脉滴注500 mg左氧氟沙星1次或2次均能达到最小的抑菌浓度。     

克雷伯氏菌产1,3-丙二醇aldH基因缺失菌株的构建

该研究利用λRed重组技术对克雷伯氏菌（Klebsiella pneumonia）中的乙醛脱氢酶（aldH）基因进行敲除,成功构建缺失菌株K.pneumonia2-1ΔaldH,与原始菌株相比,缺失菌株K.pneumonia2-1ΔaldH发酵液中乙醇产量由原来的7.24 g/L降为0.47 g/L,降低了93.51%;1,3-丙二醇产量由原来的78.83 g/L增长至82.55 g/L,提高了4.72.%;甘油转化率由60.64%增长至63.50%,提高了2.86%。缺失菌株K.pneumonia2-1ΔaldH 50 L发酵罐小试试验中,1,3-丙二醇的产量为78.13 g/L,乙醇产量为0.50 g/L。     

Endotracheal tube biofilm and ventilator‐associated pneumonia with mechanical ventilation

Objective: To analyze biofilm on internal and external surfaces of endotracheal tubes after their use in critical care patients, and to produce evidence of association between use of the tube, presence of biofilm, and the occurrence of pneumonia. Methods: This was a clinical study performed at the Intensive Care Unit of an emergency hospital in the interior of São Paulo state, Brazil. Data collection involved 30 endotracheal tubes used on adult patients for a period of ≥48 h of mechanical ventilation for scanning electron microscopy. Results: Analysis of the biofilm on the 30 tubes by scanning electron microscopy showed various abiotic and biotic structures, predominately on the internal surface, such as: fibrin network, erythrocytes, leukocytes, cocci, bacilli, and molds, among others. The intubation period of the endotracheal tube for ≥8 days represented one of the risk factors for ventilator‐associated pneumonia (RR 7.41, P < 0.001). Conclusions: The presence of the endotracheal tube permits microbial colonization, overall contributing to the development of biofilm and the occurrence of pneumonia. Microsc. Res. Tech. 77:305–312, 2014. © 2014 Wiley Periodicals, Inc.