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。     

The efficacy of nisin can drastically vary when produced in situ in model cheeses

Nisin, a bacteriocin produced by strains of Lactococcus lactis, has a broad inhibitory effect against Gram-positive bacteria. This study investigated the efficacy of nisin Z against Lactobacillus sakei when produced by a nisin-producing strain L. lactis in model cheeses manufactured with ultrafiltrated milk. These cheeses, containing 0, 4 or 10% of gelatin in their dry matter, were inoculated with both strains. Measurement of Lb. sakei loss of viability was an indirect indicator of nisin in situ efficacy. After 24 h, the loss of viability of Lb. sakei was from 0.73 ± 0.14 to 3.30 ± 0.60 log₁₀ cfu g⁻¹ in the cheeses with 0 and 10% of gelatin, respectively, indicating a better in situ efficacy of nisin when gelatin was incorporated. However, the concentration of nisin produced by Lactococcus was similar (3.5 μg g⁻¹) in all model cheeses when measured using an enzyme-linked immune sorbent assay (ELISA). The growth of Lactococcus was slightly improved when gelatin was incorporated, leading to a higher lactate concentration, which is one of the factors explaining the increased nisin efficacy. These results reinforced previous observations that prediction of nisin efficacy in complex food systems remains difficult.     

Prerequisites for effective official food control

We studied the prerequisites for official food control and their relation to the quality of controls by using 17 Finnish municipal food control units as our sample. Based on our results, units invest in creating adequate working conditions through the provision of guidance papers, pre forma templates and possibilities for staff to collectively hold discussions. However, poor orientation, tacit knowledge and incomplete commitment among staff to quality systems remain as challenges in the units. Insufficient human resources and the inability of heads of food control units to recognize problems in the workplace setting may impair the functional capacity of units. Poor workplace atmosphere and weaknesses in organization of work may also be reflected in food businesses operators' lesser appreciation toward official food controls.     

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.     

稀土生物有效性的研究进展

随着稀土在工农业的应用日渐扩展,稀土也广泛进入了生态环境,并且由食物链等渠道进入体内,因此稀土对环境、生态和人体健康的影响,以及对稀土近期和远期生物学效应的研究也越来越引起人们的关注,我国一些科研院所从不同角度探讨了稀土的某些生物学效应,为我国稀土元素的安全性评价提供基础数据。而且应当充分发挥我们这个稀土大国的优势,充分利用我们的稀土资源,进一步研究稀土的有益效应,使科研成果转化为生产力,为促进人类健康,繁荣市场经济,开辟稀土应用的新领域。     

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。     

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.     

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.     

Scoring procedures for multiple criteria decision aiding with robust and stochastic ordinal regression

We propose several scoring procedures for transforming the results of robustness analysis to a univocal recommendation. We use a preference model in form of an additive value function, and assume the Decision Maker (DM) to provide pairwise comparisons of reference alternatives. We adapt single- and multi-stage ranking methods to select the best alternative or construct a complete ranking by exploiting four types of outcomes: (1) necessary preference relation, (2) pairwise outranking indices, (3) extreme ranks, and (4) rank acceptability indices. In each case, a choice or ranking recommendation is obtained without singling out a specific value function. We compare the proposed scoring procedures in terms of their ability to suggest the same recommendation as the one obtained with the Decision Maker׳s assumed “true” value function. To quantify the results of an extensive simulation study, we use the following comparative measures (including some newly proposed ones): (i) hit ratio, (ii) normalized hit ratio, (iii) Kendall׳s τ, (iv) rank difference measure, and (v) rank agreement measure. Their analysis indicates that to identify the best “true” alternative, we should refer to the acceptability indices for the top rank(s), whereas to reproduce the complete “true” ranking it is most beneficial to focus on the expected ranks that alternatives may attain or on the balance between how much each alternative outranks and is outranked by all other alternatives.     

茂隆莪术油治疗浅度溃疡期褥疮的疗效分析

目的探讨茂隆莪术油治疗浅度溃疡期褥疮的临床疗效。方法将60例浅度溃疡期褥疮患者随机分为实验组和对照组,各30例,清洁创面后,实验组采用茂隆莪术油涂抹创面,辅以红外线照射,对照组采用庆大霉素湿敷联合红外线照射。结果实验组治愈24例,显效4例,有效2例,而对照组治愈11例,显效12例,有效5例,无效2例。2组疗效比较差异有统计学意义,P<0.01(u=2.967)。结论茂隆莪术油对浅度溃疡期褥疮治疗效果明显优于传统的庆大霉素湿敷。