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doi: 10.1111/j.1741‐2358.2011.00583.x Evaluation of compressive strength in the first premolars between young and elderly people: ex vivo study Objective: This study evaluated the compressive strength of first maxillary premolars from young and elderly people. Background: Findings have revealed that changes happening on dental structure lead to a higher susceptibility of tooth fracture. Materials and methods: Thirty teeth were divided into four groups as follows: G I (n = 7) premolars of elderly patients with fused roots, G II (n = 8) premolars of elderly with separate roots, G III (n = 7) pre‐molars of young people with fused roots and G IV (n = 8) premolars of young people with roots separated. The roots were placed in polyvinyl chloride (PVC) cylinder and embedded in acrylic resin. Afterward, the samples were subjected to fracture by compressive strength in a universal testing machine. Loads were applied in continuous and progressive speed of 0.5 mm/min until the moment of fracture. The values found underwent statistical analysis (anova α = 0.05). Results: With regard to age, there was a statistical difference, the teeth of the elderly being more susceptible to fracture (p < 0.05). With regard to root morphology, no significant differences between both groups were observed (p > 0.05). Conclusion: It was concluded that with the methodology employed, the age factor was important with regard to fracture resistance to compression.  相似文献   

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Although systematic, quantitative assessment of environmental health risks is a staple of regulatory decision-making, complaints regarding its perceived failures and shortcomings are an intrinsic feature of the policy landscape. In this article, we (a) catalog the classic criticisms of conventional health risk assessment, (b) create a typology that orders the critiques according to their focus on either input errors or output biases, and (c) identify selected allegations that fall within each category. We also note that the risk assessment–risk management paradigm has evolved over the past several decades, partially in accordance with the general direction and spirit of these classic critiques. The debate continues today along familiar lines invoking the traditional critiques and rebuttals outlined here.  相似文献   

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Objectives: To describe the initial dental treatments of Lithuanian dentate elderly patients and the content of the most recent treatment in relation to their dentist‐visiting behaviour. Materials and methods: A cross‐sectional questionnaire study was carried out at two public dental offices in Kédainiai, Lithuania, among dentate patients aged 60+ years. A self‐administered questionnaire covered first‐time dental care, the most recent dental treatment, check‐up behaviour, interval since the most recent dental visit, and number of teeth. Age, gender and education served as background information. Statistical evaluation was by chi‐squared test, anova and logistic regression for odds ratio (OR). Results: In all, 174 dentate elderly responded, mean age being 69.2 (SD = 6.6) years. The mean age at the first visit was 16.3 years [95% confidence interval (CI) 14.9–17.6]. Regular dental check‐ups were reported by 30%, and 36% had visited a dentist within the past 12 months. As to the content of the most recent treatment, 78% of the elderly reported filling therapy, 50% endodontics, 48% tooth extraction, 21% radiography, 10% cleaning or scaling and 6% polishing of fillings. Those going for check‐ups were more likely to report diagnostic (OR 1.9; 95% CI 1.1–2.8; p = 0.01) and preventive (OR 4.8; 95% CI 2.5–9.0; p = 0.002) treatment when analysed by a logistic regression model, controlling for age, gender, education and number of teeth. Conclusions: Check‐up‐orientated utilisation of dental services should be encouraged among the Lithuanian elderly. Dentists and health officials should place greater emphasis on prevention.  相似文献   

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Objective: The aim of the study was to assess the uptake of dental services by the old and very old population within the scope of the Berlin Aging Study (Berliner Altersstudie BASE ). Design: A multi‐disciplinary structured interview was performed on 928 subjects, aged from 70 to 103 years of whom 516 persons volunteered to take part in a 14‐session intensive protocol. Six representative study groups were matched for age and gender. Subjects were asked to recall the timing of their most recent dental visit. Data were validated by sending for dental records and compared with all study participants from the multi‐disciplinary intake assessment. Data were related to age group, dental state, dementia and education. Results: Reported last contact with dental services ranged from 2 weeks to 52 years (median 18 months) with a higher time lapse in the study groups aged 85 and older. Dentate subjects had seen their dentist more recently than edentate subjects. Higher education correlated with an increased dental utilisation. Subjective memory on the time lapse since the last dental appointment coincided in 13% of the subjects with available dental records (n=84), was misjudged between one and six months in 55%, and by more than six months in the remainder. Moderately or severely demented subjects who remembered their last dental appointment (n=48 of 70) showed no consistently different utilisation to healthy or mildly demented studs participants. Conclusion: Edentate old and very old subjects show the least frequent utilisation of dental services. Data on motivation and barriers to care are needed to develop strategies to improve the use of dental services and thus promote oral health in late life.  相似文献   

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生态风险评价方法述评   总被引:21,自引:6,他引:21  
张思锋  刘晗梦 《生态学报》2010,30(10):2735-2744
生态风险是由环境的自然变化或人类活动引起的生态系统组成、结构的改变而导致系统功能损失的可能性。生态风险评价是定量预测各种风险源对生态系统产生风险的或然性以及评估该风险可接受程度的方法体系,因而是生态环境风险管理与决策的定量依据。在介绍了生态风险概念的基础上,按照风险源性质的分类标准将生态风险划分为化学污染类风险源、生态事件类风险源、复合类风险源3类,并分别论述了3类生态风险对应评价方法的特点与发展的方向。另外,针对生态风险评价研究的现状,讨论了我国生态风险研究的优先领域,包括建立急性、慢性毒理数据库,构建外来生物入侵风险评价标准等,同时,建议将综合概率统计学、复杂系统理论与遥感技术等手段引入生态风险评价方法中,以进一步提高风险评价结果在生态风险管理中的有效性。  相似文献   

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生态风险评价及研究进展   总被引:30,自引:1,他引:30  
生态风险是当前环境管理研究领域中的一个热点问题,其研究着重关注化学、物理和生物的胁迫因子可能对生态系统或其组分的有害影响.生态风险评价对科学制定环境管理决策有着重要的意义.要对生态系统进行有效地管理,必须预测不利生态影响发生的可能性及后果,减小其对于生态系统或某些组分的损害程度.本文对生态风险评价的研究方法、工具以及研究趋势进行了综述,指出了目前生态风险评价中还需要进一步加强的研究领域,认为在当前城市化水平不断提高的情况下要关注城市生态风险,并针对存在的一些问题提出了今后的研究展望.  相似文献   

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Objective: The purpose of this study was to undertake a critical appraisal of oral health‐related quality of life (OHRQoL) measurements used for research in the elderly. Background: A variety of OHRQoL measurements have been developed in the past 20 years as a result of increased concern about the impact of oral conditions on a person’s quality of life. There is need for an assessment aimed at prioritising the recommended measurements to be used for different purposes in the elderly. Materials and methods: Original English language papers using measurements to assess OHRQoL in the elderly were identified from Web of Science, EMBASE, PubMed, Medline and Lilacs databases. The search included all papers published from 1985 to February 2007. The criteria of assessment were: (i) measurement criteria (number of items and domains, and classification of the results found for each measurement); (ii) quantitative–qualitative criteria (frequency, acceptability, reproducibility, reliability, sensitivity and capability of being reproduced in other language versions). Results: In a total of 152 papers selected, 20 measurements were identified. However, only seven fulfilled all the measurement and quantitative–qualitative criteria. Conclusion: Geriatric Oral Health Assessment Index, Subjective Oral Health Status Indicators, Oral Health Impact Profile‐49, Dental Impact on Daily Living, Oral Health Impact Profile‐14, Oral Impact on Daily Performances and German Version of the Oral Heath Impact Profile were considered as instruments of choice to assess OHRQoL in the elderly. The other 13 instruments identified require further research aimed at a validation process and the use of a language other than English.  相似文献   

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区域生态风险评价的关键问题与展望   总被引:10,自引:0,他引:10  
区域生态风险评价具有多风险因子、多风险受体、多评价终点、强调不确定性因素以及空间异质性的特点,它与传统的生态风险评价在风险源、胁迫因子和评价尺度上具有明显区别。尝试建立了一个基于陆地生态系统的区域生态风险评价框架,同时针对目前区域生态风险评价的研究现状,指出不确定性分析、尺度外推难、评价指标不统一、评价标准不统一、风险因子筛选及优先排序、区域内污染物复合、水生过渡到陆生生态系统风险评价、特殊的人为因素等是目前区域生态风险评价存在的关键问题及难点所在,并提出解决这些问题可能所需的工具、手段和理论方法突破。最后指出区域生态风险观测与数据采集加工、区域生态风险指标体系的统一与整合、区域生态风险评价方法论、区域生态风险的空间分布特征与表达以及区域生态风险评价反馈与管理机制5个方面是区域生态风险评价未来的研究重点。  相似文献   

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This study aimed to identify factors associated with dermal exposure to cypermethrin and assess the health risks among young children in an agricultural community in Thailand. Face-to-face interviews were conducted with the parents/caregivers of 58 children (aged 1–3 years). Wipe samples were analyzed for cypermethrin by gas chromatography-microelectron capture detection (GC-µECD). Health risk assessments were based on the cypermethrin concentration on the children’s hands and feet. Spearman’s correlation indicated significant associations among cypermethrin concentrations on the hands, feet, floors/wooden beds, and toys (rho?=?0.438–0.613, p-value <0.001). Cypermethrin concentrations on the hands were significantly and inversely correlated with the child’s caregiver being the child’s mother and insecticide use (p?<?0.01). Concentrations on the feet were significantly correlated with insecticide use (p?<?0.05) and showering (p?<?0.01). The hazard quotient calculated from dermal exposure via the hands and feet showed no risk for potential noncarcinogenic effects (5.586?×?10?5 in the dry season and 4.301?×?10?4 in the wet season). These findings suggest that young children might not be at risk for cypermethrin exposure through the dermal route. Residential exposure among young children may be reduced by improved hygiene. Health risk assessments of environmental insecticide exposure via the oral and inhalation routes require further investigation.  相似文献   

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Risk is by no means a simple concept. Natural variability and definitional problems with the concept of probability complicate the measurement and use of risk as an analytical tool. Variability requires that risk assessment methods separate natural from total risk when attempting to estimate anthropogenic risk. Failure to do so results in the over estimation of anthropogenic risk and the eventual loss of credibility for risk assessment methodologies. The common frequentist approach to probability is not consistent with anything but a modelling approach to risk assessment. When combined with its ability to account for natural variability, incorporate laboratory-assay data and offer complete statistical and experimental control, modelling is a promising approach to risk assessment. Modelling, however, is not without its drawbacks. Initialization bias can result in the over, or under, estimation of both natural and anthropogenic risk. Furthermore, model estimates are time dependent. The convergence of natural and anthropogenic risk poses problems for modelling-based risk assessment and requires clear statements as to the importance of the time dimension in risk assessment. When combined, the drawbacks to modelling-based risk assessment argue that risk should never be stated as a scalar quantity. Instead, modelling-based risk assessment should provide estimates of the complete range of risk measures (total, natural, and anthropogenic) as well as indications of convergence time. Only then can the modelling-based approach be viewed as the most appropriate means of carrying out scientifically credible risk assessment.  相似文献   

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目的:调查广西边疆某城市农村壮族老人跌倒风险及跌倒发生率,探讨简化24式太极拳结合肌力、平衡训练及安全教育对降低老年人跌倒发生的效果。方法:在广西边疆某市采用整群分层抽样法抽取1980名60岁以上的农村老年人(男性840人,女性1140人),调查近1年来跌倒发生情况,应用卫生部老年人跌倒干预技术指南评估表和MORSE(莫尔斯)跌倒风险评估表对调查对象进行风险评估;选取64名1年中跌倒2次以上的患者为研究对象,分为对照组和试验组(每组32名),对照组不进行运动干预并保持先前的生活习惯,试验组进行24周的24式太极拳结合肌力、平衡训练。使用记录卡记录两组受试者干预期间和干预结束半年后的跌倒发生情况并与干预前1年相比。结果:受调查的老年男性跌倒发生率为27.1%,女性跌倒率为18.6%,平均跌倒率为22.2%;按照卫生部老年人跌倒干预技术指南评估表评估,男性得分为7.16,女性为6.92,平均得分为7.04,属跌倒发生中危状态;按照摩尔斯量表评估,男性得分为37.76,女性为32.22,平均得分为35.09,属中危或轻危状态;干预后和干预后半年两组受试者跌倒发生率都有所下降,其中对照组下降了...  相似文献   

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随着全球水产养殖业的发展,水产动物活体或水产品贸易日益频繁,不可避免地给进口国带来病原风险,造成疾病引入和传播,甚至生物入侵,严重危害水产养殖业的发展。水生动物进口风险评估(IRA),是指从别国或地区进口水生动物活体包括其受精卵、稚鱼、幼鱼、苗种、成体以及商品等的风险分析。风险分析是指对风险事件进行科学、透明、系统分析的一个过程,它由危害识别、风险评估、风险交流和风险管理4个部分构成。目前,常用的风险评估方法有定性风险评估、半定量风险评估和定量风险评估3种。定性风险评估具有灵活性强、适用范围广、易掌握的特点,能够综合各种资料、数据和信息,尤其适合初次风险评估,但容易受评估人员主观因素的影响。定量风险评估可避免主观因素的影响,评估结果准确、可靠,但需要收集大量数据,工作量巨大,评估成本也很高。通常,定性评估结果若能够提供很好的防范措施,则不必进行定量评估。将外来水生病原阻止在引进之初远比引入后根除更加容易。因此,开展水生动物进口风险评估对于阻止水生动物疾病传播和水生态环境破坏具有重要意义,同时也可为各国进行水产贸易提供参考。  相似文献   

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生态风险评价研究进展   总被引:57,自引:5,他引:57  
陈辉  刘劲松  曹宇  李双成  欧阳华 《生态学报》2006,26(5):1558-1566
20多年来,生态风险评价研究经历了从环境风险到生态风险到区域生态风险评价的发展历程,风险源由单一风险源扩展到多风险源,风险受体由单一受体发展到多受体,评价范围由局地扩展到区域景观水平.区域生态风险评价就是大尺度上研究复杂环境背景下包含多风险源、多风险受体的综合风险研究.目前,区域生态风险评价的理论框架已经搭建起来,统计方法多采用相对评价法.区域生态风险评价未来的发展方向为继续加强实验和野外调查,进一步减小不确定性,逐步解决尺度推移问题.区域生态风险评价必须与经济、社会、文化相结合,才能充分发挥它在管理决策中的作用.  相似文献   

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This overview paper provides the historical context for the incorporation of lifestage‐specific concerns in human health risk assessment, briefly explains the process employed in a lifestage framework for risk assessment, and discusses the scientific rationale for how utilizing lifestage data will strengthen the overall risk assessment process. This risk assessment approach will add value by: (1) providing a more complete evaluation of the potential for vulnerability at different lifestages, including a focus on the underlying biological events and incorporation of mode of action information related to different critical developmental periods; (2) evaluating the potential for toxicity during all lifestages after early lifestage exposure; (3) reviewing the importance of integrating exposure information and adverse health effects across lifestages; and (4) serving as a basis to extend some aspects of the children's health risk assessment framework to all lifestages. Birth Defects Res (Part B), 2008. © 2008 Wiley‐Liss, Inc.  相似文献   

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