一起学校水痘暴发的流行因素及其疫苗保护效率调查

目的调查一起学校水痘暴发的流行因素,探讨水痘疫苗的保护效率。方法采用1∶1频数匹配病例对照研究方法,即以病例作为病例组,随机选择同班级、同性别,且无水痘患病史的相同数量未发病的健康学生作为对照组。使用自行设计的水痘危险因素调查表,对病例和对照进行问卷调查。结果此次疫情共报告32例水痘病例,总罹患率为0.80%。波及深圳市龙岗区某学校4个班级,其中二年级23例,五年级9例,各班罹患率差异有统计学意义(P<0.05);接种过水痘疫苗的病程时间(中位时间5 d)比未接种过水痘疫苗的病程时间(中位时间10 d)短;经常与其他年级或班级学生玩耍感染水痘的危险性是未与其他年级或班级学生玩耍的10.71倍,接触班里水痘病例的危险性是未接触的41.89倍;水痘疫苗的保护效率为6.76%,95%CI:10.00%～83.51%。接种进口水痘疫苗的罹患率远低于接种国产疫苗的罹患率(P<0.05)。结论这是一起发生在某小学的水痘暴发疫情,经常与其他班级或年级的学生玩耍以及水痘疫苗保护效率欠佳,是此次疫情暴发的危险因素。     

浅谈学生公寓信息化管理平台的搭建与效用

现在的社会是一个发展快速的高科技信息化社会,计算机的应用已经遍及到社会的各个领域。对于拥有优秀人才、先进技术的高等院校,搭建公寓信息化管理平台,加强公寓管理,提高工作效率与管理水平。实现对公寓进行全面的信息化管理,是公寓管理发展的必然方向。     

On sensitivity of detector structures to contaminants in non-white mixture noise model

In this paper, we study the structure of the locally optimal detector in non-white transformation noise with -contaminated marginal density. We show that each of the memoryless nonlinearities in the detector can be at least approximately represented as a term for the nominal density plus a correction term in closed form that is directly proportional to . The approximations are found, by simulation, to be good in most cases except when is large and the tail weight of the contaminant is large. We also show that the eigenfunctions of the bivariate noise density can be put in a similar form.     

Challenges in using administrative enforcement measures in local food control

We surveyed Finnish local food control officials’ opinions about the use and challenges of administrative enforcement measures. Responses to the questionnaire were received from a total of 129 food control officials, covering 72.6% of the 62 local food control units in Finland. In the opinion of 42.7% of the respondents, enforcement measures are not used often enough in their unit to ensure food safety. Based on our results, large units have better practical tools such as templates for enforcement decisions and guidelines that facilitate the use of enforcement measures than small units, but uncertain practices and a lack of routine appear to impede the use of the measures in many units. Particular challenges highlighted by the officials were related to laboriousness and slowness of the administrative process and reasoning for using enforcement measures. Moreover, impairment of cooperation with the food business operator as a consequence of using enforcement measures was of concern for many officials. The officials assessed the expertise of the head of the unit more positively in the units in which enforcement measures were used than in the units in which enforcement measures were not used, and participation in trainings was the strongest explanatory factor for the use of enforcement measures among the inspectors. Our results indicate that development of operating procedures and provision of specific training on administrative procedure with a practical approach play a key role in strengthening officials’ expertise and confidence in using enforcement measures. Moreover, merging the small units with the large ones may promote uniform practices and better capabilities to use enforcement measures in all units.     

Efficacy and Safety of Triazavirin Therapy for Coronavirus Disease 2019: A Pilot Randomized Controlled Trial

No therapeutics have been proven effective yet for the treatment of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To assess the efficacy and safety of Triazavirin therapy for COVID-19, we conducted a randomized, double-blinded controlled trial involving hospitalized adult patients with COVID-19. Participants were enrolled from ten sites, and were randomized into two arms of the study with a ratio of 1:1. Patients were treated with Triazavirin 250 mg versus a placebo three or four times a day for 7 d. The primary outcome was set as the time to clinical improvement, defined as normalization of body temperature, respiratory rate, oxygen saturation, cough, and absorption of pulmonary infection by chest computed tomography (CT) until 28 d after randomization. Secondary outcomes included individual components of the primary outcome, the mean time and proportion of inflammatory absorption in the lung, and the conversion rate to a repeated negative SARS-CoV-2 nucleic acid test of throat swab sampling. Concomitant therapeutic treatments, adverse events, and serious adverse events were recorded. Our study was halted after the recruitment of 52 patients, since the number of new infections in the participating hospitals decreased greatly. We randomized 52 patients for treatment with Triazavirin (n = 26) or a placebo (n = 26). We found no differences in the time to clinical improvement (median, 7 d versus 12 d; risk ratio (RR), 2.0; 95% confidence interval (CI), 0.7–5.6; p = 0.2), with clinical improvement occurring in ten patients in the Triazavirin group and six patients in the placebo group (38.5% versus 23.1%; RR, 2.1; 95% CI, 0.6–7.0; p = 0.2). All components of the primary outcome normalized within 28 d, with the exception of absorption of pulmonary infection (Triazavirin 50.0%, placebo 26.1%). Patients in the Triazavirin group used less frequent concomitant therapies for respiratory, cardiac, renal, hepatic, or coagulation supports. Although no statistically significant evidence was found to indicate that Triazavirin benefits COVID-19 patients, our observations indicated possible benefits from its use to treat COVID-19 due to its antiviral effects. Further study is required for confirmation.     

东南亚食用燕窝研究现状

东南亚各国的食用燕窝为金丝燕筑巢时吐出并凝固的唾液,具有丰富的营养和药用价值,在国内自古被视为珍稀食材。随着燕窝产业的发展和经济水平的提高,食用燕窝逐渐平民化。与此同时,许多不法分子为谋取暴利采用化学漂白等方式进行掺假。2011年以来,正规渠道入境的燕窝先后爆发过"毒血燕"、"换码"、"虚标含量"等质量事件,其食用安全问题备受关注,各国对其成分、功效、生物活性、检测方法、法规标准等的研究也逐渐深入。本文从金丝燕的物种、燕窝的种类、产业链和相关法律法规的现状、燕窝的成分和功效、燕窝的真伪鉴定6个方面对食用燕窝进行全方位、多角度、深层次的综述,以期为下一步研究提供参考依据。     

保湿化妆品功效评价与发展展望

保湿化妆品越来越被人们所重视,其安全性和功效性评价自然成为消费者和生产厂家所关注的重点。本文从科学角度介绍了保湿化妆品的保湿原理,主要活性成分,作用机制,并重点介绍了国内外对保湿化妆品功效评价的进展情况,包括保湿活性成分的检测和分析、重量法、Corneometer仪器电容测试法、Skincon仪器电导测试法、Tewameter仪器经表皮水分流失值测试法、IR测试,以及一些其它的保湿功效评价方法,等等,同时展望了保湿化妆品的未来发展趋势,为我国保湿化妆品产品的发展提供了参考。     

Responses of phosphine susceptible and resistant strains of five stored-product insect species to chlorine dioxide

Adults of phosphine susceptible laboratory strains and phosphine resistant field strains of five stored-product insect species were exposed in vials with 0 or 10 g of wheat for different time periods to 0.54 g/m³ (200 ppm) of chlorine dioxide gas. After exposure, adult mortality was determined 5 d later at 28 °C and 65% r.h. The 5-d mortality was 100% in laboratory and field strains of the red flour beetle, Tribolium castaneum (Herbst); sawtoothed grain beetle, Oryzaephilus surinamensis (L.); lesser grain borer, Rhyzopertha dominica (F.); maize weevil, Sitophilus zeamais Motschulsky; and rice weevil, Sitophilus oryzae (L.) that were exposed in vials with 10 g of wheat to chlorine dioxide for 26, 16, 24–34, 18–24, and 15–18 h, respectively. Corresponding exposure durations for these species and strains in vials without wheat were 15, 3, 18–20, 7–15, and 5–7 h, respectively. Dosages of chlorine dioxide producing 99% mortality (LD₉₉) of T. castaneum, O. surinamensis, R. dominica, S. zeamais, and S. oryzae strains in vials with wheat ranged from 14.79−22.57, 8.20–8.41, 15.79–21.60, 10.66–14.53, and 7.67–12.20 g-h/m³, respectively. In vials without wheat, corresponding LD₉₉ values for T. castaneum, R. dominica, and S. zeamais strains were 6.51–8.66, 11.46–23.17, and 5.79–10.26 g-h/m³, respectively. LD₉₉ values for O. surinamensis and S. oryzae could not be computed, because of 100% mortality after a 3–5 h exposure to chlorine dioxide. No adult progeny production of T. castaneum and O. surinamensis was observed after 8 weeks in control and chlorine dioxide-exposed samples. Adult progeny production of Sitophilus spp. was found only in the control samples. The dosage for 99% adult progeny reduction relative to control for R. dominica strains ranged from 10.07 to 18.11 g-h/m³. Chlorine dioxide gas is effective in killing phosphine susceptible and resistant strains of five stored-product insect species and suppressing adult progeny production of three out of the five species.     

On the Efficacy of IF–WS<Subscript>2</Subscript> Nanoparticles as Solid Lubricant: The Effect of the Loading Scheme

Fullerene-like WS₂ (MoS₂) nanoparticles (IF) have been studied in the past as solid lubricants. Using the tribological ball-on-flat experiments, it was shown that the size of the aggregates and their distribution determine the penetration and entrapping of the IF nanoparticles at the interface. It is expected that the wedge clearance at the inlet of the contact, i.e., the oblique-angle entrance to the contact zone between the two mating tribological surfaces, as well as the average surface roughness, can limit the supply of the lubricant into the interface in, e.g., the block-on-ring experiment. In the present series of experiments, the Stribeck curve was designed first using a linear loading scheme and pure oil. It was concluded that a wedge clearance (oblique-angle) in the inlet of the contact zone leads to entrapment of the IF nanoparticles and their compaction, which hamper the supply of the fluid lubricant into the interface. A ball-on-flat and flat block-on-ring friction devices with wedge clearance in the inlet of the contact can distort the efficacy of IF. Procedures for improving the supply of the IF nanoparticles to the contact zone and improving thereby their efficacy are considered.     

滑坡灾害风险评估的FA-ECM法

滑坡灾害在我国具有分布广、规模大、数量多且危险性强等特点,给人民的生命财产带来严重的威胁,所以,必须加强滑坡灾害的评估方法研究。为此,基于功效系数法(ECM)的基本原理,在综合考虑滑坡的众多影响因素基础上,运用因子分析法(FA),选取坚固性系数、坡度、当月降雨量、植被覆盖率、距坝距离、断层影响距作为评价因子,建立了一种新的滑坡灾害风险评估方法,并将该方法应用于瀑布沟水电站库区12处滑坡灾害,评价结果的准确率达到91.77%,表明基于FA-ECM法的滑坡灾害风险评估方法是可行的,这为滑坡灾害的风险评估提供了一种新的方法。