呼吸道吸入天然钍（ThO2）和稀土矿尘联合作用的研究

本文通过体内实验、体外实验和人群流行病学调查等３个方面，对天然钍（ＴｈＯ２）和含钍稀土矿尘可能存在的联合作用进行了研究。结果表明：（１）大鼠气管注入含钍稀土矿尘后，在肺内的滞留方程可表示为：Ｒ（ｔ）＝０．７５×２－ｔ／２２．７＋０．２５×２－ｔ／３５４；（２）大鼠气管注入ＴｈＯ２有明显的致癌作用，同时看到了Ｆｅ２Ｏ３对ＴｈＯ２致癌作用可能存在的促进作用；（３）动物实验表明，１８ｍｇＴｈＯ２的致纤维化能力与５０ｍｇ含钍稀土矿尘的作用相当，由于矿尘中ＴｈＯ２含量很低（０．０４％），ＳｉＯ２含量相对较高（１０％），结合人群流行病学调查结果，可以认为接尘矿工中肺功能障碍和０＋期尘肺的出现，主要是矿尘中ＳｉＯ２所引起，ＴｈＯ２的作用甚微；（４）体外实验表明，ＴｈＯ２和含钍稀土矿尘均可使金黄地鼠胚胎细胞发生恶性转化，将恶性转化细胞接种于金黄地鼠颊囊粘膜下，均有肿瘤发生，为分化较好的纤维肉瘤。同时也看到了Ｆｅ２Ｏ３对ＴｈＯ２致癌作用可能存在的促进作用；（５）流行病学调查表明，白云鄂博矿接尘矿工呼出气中气土活度高于对照组，在调查期间（１９７７－１９９０年）未发现肺癌死亡率的增加     

Driving with pets as a risk factor for motor vehicle collisions among older drivers

Increasing rates of distraction-related motor vehicle collisions (MVCs) continue to raise concerns regarding driving safety. This study sought to evaluate a novel driving-related distraction, driving with a pet, as a risk factor for MVCs among older, community dwelling adults. Two thousand licensed drivers aged 70 and older were identified, of whom 691 reported pet ownership. Comparing pet owners who did and did not drive with their pets, neither overall MVC rates (rate ratio [RR] 0.97, 95% confidence interval [CI] 0.75–1.26) nor at-fault MVC rates (RR 0.84, 95% CI 0.57–1.24) were elevated. However, those who reported always driving with a pet in the vehicle had an elevated MVC rate (RR 1.89, 95% CI 1.10–3.25), as compared to those who did not drive with a pet. The MVC rate was not increased for those reporting only sometimes or rarely driving with a pet in the vehicle. The current study demonstrates an increased risk of MVC involvement in those older drivers who always take a pet with them when they drive a vehicle. When confronted with an increased cognitive or physical workload while driving, elderly drivers in prior studies have exhibited slower cognitive performance and delayed response times in comparison to younger age groups. Further study of pet-related distracted driving behaviors among older drivers as well as younger populations with respect to driver safety and performance is warranted to appropriately inform the need for policy regulation on this issue.     

Depression and nonadherence predict mortality in hemodialysis treated end-stage renal disease patients

The scientific evaluation of depression's impact on mortality in hemodialysis (HD) patients has yielded mixed results, with the more recent, more rigorous studies detecting a significant relationship. In this study, 130 HD patients from an urban North American hospital were evaluated for depressive affect and then observed for up to 5 years. In a corrected Cox regression model, which held constant age, gender, dialysis vintage, illness severity and diabetic status, depressive affect emerged as a modest but significant predictor of mortality (relative risk = 1.05, 95% confidence interval = 1.01–1.08). When the subjects were divided according to depressive affect severity, those with severe depressive affect had significantly shorter time to death (β = 0.452, P = 0.044). In a subgroup of 85 subjects, self‐reported medication adherence was also predictive of mortality, with higher rates of nonadherence being associated with increased mortality risk. This paper lends support to the burgeoning literature on depression and reduced survival in HD populations, as well as begins the investigation of understanding the underlying mechanisms.     

The motorcyclist impact against a light vehicle: Epidemiological,accidentological and biomechanic analysis

This paper summarizes the results obtained within the framework of the French PROMOTO Project (PROtection of the MOTOrcyclist). The aim of this project was to analyze the impact between a motorcycle and a light vehicle from an epidemiological, accidentological and biomechanical point of view. The results have made it possible to outline the most frequent accident configurations such as the “turn on the left” and the most common injuries sustained by motorized two-wheelers (head and trunk). The biomechanic analysis has enabled a better understanding of the kinematics involved in an impact between a motorized two-wheeler and a light vehicle in various accident configurations (chronology and speed impact). While it is well known that motorcyclists frequently receive life threatening injuries to the head, spine and torso, this paper has been able to observe specific injury mechanisms such as pelvis impacts against the vehicle fuel tank and hyper-extension of the neck due to head impact on passenger cars.     

A concise cost analysis of Internet malware

In this paper we present a cost model to analyze impacts of Internet malware in order to estimate the cost of incidents and risk caused by them. The model is useful in determining parameters needed to estimate recovery efficiency, probabilistic risk distributions, and cost of malware incidents. Many users tend to underestimate the cost of curiosity coming with stealth malware such as email-attachments, freeware/shareware, spyware (including keyloggers, password thieves, phishing-ware, network sniffers, stealth backdoors, and rootkits), popups, and peer-to-peer fileshares. We define two sets of functions to describe evolution of attacks and potential loss caused by malware, where the evolution functions analyze infection patterns, while the loss functions provide risk-impact analysis of failed systems. Due to a wide range of applications, such analyses have drawn the attention of many engineers and researchers. Analysis of malware propagation itself has little to contribute unless tied to analysis of system performance, economic loss, and risks.     

Dynamical analysis of plant disease models with cultural control strategies and economic thresholds

In this paper plant disease models including impulsive cultural control strategies were developed and analyzed. The sufficient conditions under which the infected plant free periodic solution with fixed moments is globally stable are obtained. For the model with an economic threshold (ET) of infected plants, detailed investigations imply that the number of healthy plants either goes to extinction or tends to infinity, and the maximum value of infected plants is always less than the given ET. In order to prevent the healthy plant population going to extinction, we further propose a bi-threshold-value model, which has richer dynamical behavior including order 1-k or order k-1 periodic solutions with k≥1$k\ge 1$. Under certain parameter spaces, the infected plant free periodic solution is globally stable for the bi-threshold-value model. The modeling methods and analytical analysis presented can serve as an integrating measure to identify, evaluate and design appropriate plant disease control strategies.     

Sick Building Syndrome (SBS) in Office Workers and Facial Skin Symptoms among VDT-Workers in Relation to Building and Room Characteristics: Two Case-Referent Studies

In two case-referent studies the associations between questionnaire symptom reports, expressed as SBS (Sick Building Syndrome) in office workers or facial skin symptoms among VDT-workers, and physical data from offices in 160 buildings were investigated. The results show that low outdoor airflow rate and presence of certain pollution sources, such as copying machines, tended to be associated with an elevated prevalence of SBS. Buildings built or remodeled between 1977 and 1986, low-rise buildings with a horizontal roof and a foundation of the type “concrete slab on the ground”, as well as rooms with flourescent tube lighting with metal shields were also associated with higher SBS risks. A number of factors were associated with an overrepresentation of skin symptoms among VDT-workers such as type of foundation (concrete slab on the ground and crawlspace), the frequency of floor cleaning and type of lighting (fluorescent tubes with glass/plastic shields). It has not been possible to establish conclusive explanations for these associations. The difference in associations between building factors and S B S, and between building factors and skin symptoms among VD Tworkers points to different etiologies.     

Prevalence, distribution, and molecular characterization of Salmonella recovered from swine finishing herds and a slaughter facility in Santa Catarina, Brazil

Swine can carry Salmonella strains that may be transmitted to humans by pork products. This investigation determined the distribution and types of Salmonella in 12 swine finishing herds and a slaughter facility in Santa Catarina, Brazil. A total of 1258 samples, consisting of environmental, feed, carcass, lymph node, and fecal material were collected and submitted to bacteriological isolation of Salmonella. From 487 positive samples, 1255 isolates were recovered and confirmed to be Salmonella. The distribution of positive samples was as follows: finishing pen floors 26% (16/61); feed 29% (42/143); feces 44% (52/119); pooled feces 59% (35/59); slaughter holding pens 90% (36/40); lymph nodes 46% (220/478); pre-chilled carcass surfaces 24% (24/98); and post-chilled carcass surfaces 24% (62/260). The most prevalent serovars were Typhimurium, Panama, Senftenberg, Derby, and Mbandaka. By pulsed-field gel electrophoresis, 1071 isolates were subtyped using XbaI, and duplicate isolates were removed. From the remaining 747 isolates, 163 macrorestriction profiles (pulsotypes) were identified. Six pulsotypes were considered very frequent, occurring in 33 isolates or more. The multiple correspondence analyses showed correlations between pulsotypes from shedding pigs (feces), herd environment (pen floors), and subiliac and prescapular lymph nodes and between lairage and carcass surface samples before and after chilling. All sources of Salmonella investigated contributed to the carrier state; however, pre-slaughter contamination at lairage was the variable most strongly associated with carcass contamination. A total of 59 different antimicrobial resistance profiles were observed in 572 Salmonella isolates. From these isolates, 17% (97/572) were susceptible to all 15 antibiotics tested, 83% (475/572) were resistant to at least one, and 43% (246/572) were resistant to four or more antibiotics (multi-resistant). The AmpGenKanTet profile was the most prevalent in carcass isolates and was associated with farm origin.     

A modeling framework to accelerate food-borne outbreak investigations

Food safety procedures are critical to reducing pathogen caused food-borne disease (FBD). However there is no way to completely eliminate the risk of consuming contaminated products. When prevention efforts fail, rapid identification of the contaminated product is essential. The medical and economic losses incurred grow with the duration of the outbreak. In this paper we show that before an outbreak occurs, analysis of food sales data, as a proactive intervention, can provide useful product intelligence that we can exploit during an outbreak investigation to accelerate the identification process. Using real grocery retail sales data from Germany, we have implemented a likelihood-based approach to study how such data can be used to accelerate the investigation during the early stages of an outbreak.     

Haloacetic acids in drinking water in the United Kingdom

We measured concentrations of haloacetic acids (HAAs) in the water supply in regions covered by three water companies in the UK Approximately 30 samples in each region were obtained for analysis of both THMs and HAAs to assess the levels of HAAs and the relationship between HAAs and THMs, temperature, pH, free and total chlorine. We have found that there is a range of HAA levels in drinking water with the means ranging from 35-95mug/l and a maximum concentration of 244mug/l. In two out of the three regions there was a high correlation between total THMs and total HAAs, but whereas the HAA and THM levels in one of these companies were approximately equal, in another company the HAA levels were 3-4 times higher than the THM levels. In the third region there was no correlation between total THMs and total HAAs even though the average levels were approximately equal. The ratio of total THM and total HAAs levels was significantly correlated with temperature, pH, free and total chlorine. Overall total THM levels are therefore not considered to be a good indicator of HAA levels. Epidemiological studies using total THM levels should be taking this into account in the interpretation of their results, and regulatory authorities when setting water guidelines.