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排序方式: 共有891条查询结果,搜索用时 15 毫秒
811.
Firewood is commonly used around the world, but little is known about the work involved in its production and associated accidents. The objectives were to identify relationships between accidents and time exposure, workers’ age and sex, equipment used and work activities in family forestry's firewood production. Data from a postal survey in Northern Sweden were compared to a database of injuries in the same region. Most accidents occurred to 50–69 year old men, who also worked most hours. No significant differences in sex and age were found between expected and recorded accident frequencies when calculated from total work hours; however, when calculated using numbers of active persons significant differences were found for both age and sex. Frequency of accidents per unit worked time was higher for machine involving activities than for other activities. Accidents that occurred when using wedge splitter machines were responsible for most of this overrepresentation. Fingers were the most commonly injured body parts. Mean accident rate for the equipment used was 87 accidents per million work hours, and the rate was highest for wedge splitters (122 accidents per million work hours). Exposure to elevated risks due to violation of safety procedures is discussed, as well as possible preventative measures. 相似文献
812.
McKenzie K Enraght-Moony E Harding L Walker S Waller G Chen L 《Accident; analysis and prevention》2008,40(2):714-718
Complete and accurate information about hospitalised injuries is essential for injury risk and outcome research, though the accuracy and reliability of hospital data for injury surveillance are often questioned. To ascertain clinical coders' views of the reasons for a lack of specificity in external cause code usage and ways to improve external cause coding, a nationwide survey of coders was conducted in Australia in 2006. Four hundred and two coders participated in the questionnaire. The results of this study show that discharge summaries and doctors' notes were the poorest source of information regarding external causes, place of injury occurrence, and activity at the time of injury. Coders viewed missing external cause information and missing documentation as having the greatest impact on the quality of external cause coding. A large majority of coders suggested that improving clinical documentation in the emergency department and introducing a centralised structured form for external cause information would improve the quality of external cause coding. Clinical coders are a valuable source of information regarding problems with, and solutions to the collection of high quality data and this research has highlighted several areas where improvements can be made and further research is needed. 相似文献
813.
Emma Sparr Danielle Millecamps Muriel Isoir Véronique Burnier ?sa Larsson Bernard Cabane 《Journal of the Royal Society Interface》2013,10(80)
The skin is a barrier membrane that separates environments with profoundly different water contents. The barrier properties are assured by the outer layer of the skin, the stratum corneum (SC), which controls the transepidermal water loss. The SC acts as a responding membrane, since its hydration and permeability vary with the boundary condition, which is the activity of water at the outer surface of the skin. We show how this boundary condition can be changed by the application of a barrier cream that makes a film with a high resistance to the transport of water. We present a quantitative model that predicts hydration and water transport in SC that is covered by such a film. We also develop an experimental method for measuring the specific resistance to water transport of films made of occluding barrier creams. Finally, we combine the theoretical model with the measured properties of the barrier creams to predict how a film of cream changes the activity of water at the outer surface of the SC. Using the known variations of SC permeability and hydration with the water activity in its environment (i.e. the relative humidity), we can thus predict how a film of barrier cream changes SC hydration. 相似文献
814.
Yoon‐Tae Kang Emma Purcell Colin Palacios‐Rolston Ting‐Wen Lo Nithya Ramnath Shruti Jolly Sunitha Nagrath 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(47)
Extracellular vesicles (EVs) are emerging as a potential diagnostic test for cancer. Owing to the recent advances in microfluidics, on‐chip EV isolation is showing promise with respect to improved recovery rates, smaller necessary sample volumes, and shorter processing times than ultracentrifugation. Immunoaffinity‐based microfluidic EV isolation using anti‐CD63 is widely used; however, anti‐CD63 is not specific to cancer‐EVs, and some cancers secrete EVs with low expression of CD63. Alternatively, phosphatidylserine (PS), usually expressed in the inner leaflet of the lipid bilayer of the cells, is shown to be expressed on the outer surface of cancer‐associated EVs. A new exosome isolation microfluidic device (newExoChip), conjugated with a PS‐specific protein, to isolate cancer‐associated exosomes from plasma, is presented. The device achieves 90% capture efficiency for cancer cell exosomes compared to 38% for healthy exosomes and isolates 35% more A549‐derived exosomes than an anti‐CD63‐conjugated device. Immobilized exosomes are then easily released using Ca2+ chelation. The recovered exosomes from clinical samples are characterized by electron microscopy and western‐blot analysis, revealing exosomal shapes and exosomal protein expressions. The newExoChip facilitates the isolation of a specific subset of exosomes, allowing the exploration of the undiscovered roles of exosomes in cancer progression and metastasis. 相似文献
815.
Weigu Li Zheng Li Karina Bertelsmann Donglei Emma Fan 《Advanced materials (Deerfield Beach, Fla.)》2019,31(29)
Solar steaming has emerged as a promising green technology that can address the global issue of scarcity of clean water. However, developing high‐performance, cost‐effective, and manufacturable solar‐steaming materials, and portable solar steaming‐collection systems for individuals remains a great challenge. Here, a one‐step, low‐cost, and mass‐producible synthesis of polypyrrole (PPy) origami‐based photothermal materials, and an original portable low‐pressure controlled solar steaming‐collection unisystem, offering synergetic high rates in both water evaporation and steam collection, are reported. Due to enhanced areas for vapor dissipation, the PPy origami improves the water evaporation rate by at least 71% to 2.12 kg m?2 h?1 from that of a planar structure and exhibits a solar–thermal energy conversion efficiency of 91.5% under 1 Sun. When further controlling the pressure to ≈0.17 atm in the steaming‐collection unisystem, the water collection rate improves by up to 52% systematically and dramatically. Although partial energy is utilized toward obtaining low‐pressure, evaluations show that the overall energy efficiency is improved remarkably in the low‐pressure system compared to that in ambient pressure. Furthermore, the device demonstrates effective decontamination of heavy metals, bacteria, and desalination. This work can inspire new paradigms toward developing high‐performance solar steaming technologies for individuals and households. 相似文献
816.
Rachel Sacks-Davis Emma McBryde Jason Grebely Margaret Hellard Peter Vickerman 《Journal of the Royal Society Interface》2015,12(104)
Hepatitis C virus (HCV) reinfection rates are probably underestimated due to reinfection episodes occurring between study visits. A Markov model of HCV reinfection and spontaneous clearance was fitted to empirical data. Bayesian post-estimation was used to project reinfection rates, reinfection spontaneous clearance probability and duration of reinfection. Uniform prior probability distributions were assumed for reinfection rate (more than 0), spontaneous clearance probability (0–1) and duration (0.25–6.00 months). Model estimates were 104 per 100 person-years (95% CrI: 21–344), 0.84 (95% CrI: 0.59–0.98) and 1.3 months (95% CrI: 0.3–4.1) for reinfection rate, spontaneous clearance probability and duration, respectively. Simulation studies were used to assess model validity, demonstrating that the Bayesian model estimates provided useful information about the possible sources and magnitude of bias in epidemiological estimates of reinfection rates, probability of reinfection clearance and duration or reinfection. The quality of the Bayesian estimates improved for larger samples and shorter test intervals. Uncertainty in model estimates notwithstanding, findings suggest that HCV reinfections frequently and quickly result in spontaneous clearance, with many reinfection events going unobserved. 相似文献
817.
Mark Ainsworth Joe Coyle 《International journal for numerical methods in engineering》2003,58(14):2103-2130
The problem of constructing hierarchic bases for finite element discretization of the spaces H1, H ( curl ), H ( div ) and L2 on tetrahedral elements is addressed. A simple and efficient approach to ensuring conformity of the approximations across element interfaces is described. Hierarchic bases of arbitrary polynomial order are presented. It is shown how these may be used to construct finite element approximations of arbitrary, non‐uniform, local order approximation on unstructured meshes of curvilinear tetrahedral elements. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
818.
Emma Southall Tobias S. Brett Michael J. Tildesley Louise Dyson 《Journal of the Royal Society Interface》2021,18(182)
Early warning signals (EWSs) are a group of statistical time-series signals which could be used to anticipate a critical transition before it is reached. EWSs are model-independent methods that have grown in popularity to support evidence of disease emergence and disease elimination. Theoretical work has demonstrated their capability of detecting disease transitions in simple epidemic models, where elimination is reached through vaccination, to more complex vector transmission, age-structured and metapopulation models. However, the exact time evolution of EWSs depends on the transition; here we review the literature to provide guidance on what trends to expect and when. Recent advances include methods which detect when an EWS becomes significant; the earlier an upcoming disease transition is detected, the more valuable an EWS will be in practice. We suggest that future work should firstly validate detection methods with synthetic and historical datasets, before addressing their performance with real-time data which is accruing. A major challenge to overcome for the use of EWSs with disease transitions is to maintain the accuracy of EWSs in data-poor settings. We demonstrate how EWSs behave on reported cases for pertussis in the USA, to highlight some limitations when detecting disease transitions with real-world data. 相似文献
819.
Associations between demographic characteristics, school schedules, activity choices, family functioning, and sleep behaviors were estimated using nationally representative time-diary data from 2,454 children (ages 5.5 to 11.9 years) and adolescents (ages 12.0 to 19.1 years). For weekdays, African American adolescents, Asian children, and those with earlier school start times and longer travel times to school reported fewer sleep hours. More time spent watching television (for children), doing homework (for adolescents), and engaging in religious activities predicted fewer hours, whereas a longer time spent on meals predicted greater hours of weekday sleep. For younger children, greater parental warmth predicted more hours of weekday sleep, whereas for adolescents, stricter household rules were protective. On weekends, African American adolescents and Hispanic children slept less, and there were strong effects of activity choices including time spent on television, computer and videogames, sports, religious activities, socializing, and employment. In accounting for age-related decreases in sleep hours from childhood to adolescence, earlier school start times, greater hours of homework, greater paid employment, less time spent on meals, and fewer household rules were all significant mediators. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
820.
NN Finer A Tierney PC Etches A Peliowski W Ainsworth 《Canadian Metallurgical Quarterly》1998,33(9):1331-1337
BACKGROUND/PURPOSE: The purpose of this study was to evaluate the evolving outcome of newborns who have congenital diaphragmatic hernia (CDH) using a protocolized approach to management, which includes extracorporeal membrane oxygenation (ECMO) and to present the details of such a management protocol. METHODS: A retrospective chart review was conducted of the neonatal outcome of near-term (>34 weeks' gestation) newborns with CDH all referred to the Royal Alexandra Hospital either before or after delivery. A protocol was developed that included antenatal assessment, the use of antenatal steroids, planned delivery, use of prophylactic surfactant, pressure limited gentle ventilation, permissive hypercarbia and hypoxia, and venovenous ECMO, if indicated. RESULTS: Sixty-five infants with CDH were treated from February 1989 through August 1996. Twenty-three infants were inborn, 20 of whom were antenatal referrals. Overall, 51 of the 65 infants survived (78%). Thirteen of the 23 inborn infants survived with conservative management, and 10 required ECMO, of whom, eight were long-term survivors. Thirty-eight infants required ECMO, and 26 survived (68%), whereas there were only two deaths among the 27 conservatively treated infants. Eighteen of 20 inborn infants with an antenatal diagnosis survived, compared with 13 of 21 (62%) outborn infants. An antenatal diagnosis before 25 weeks' gestation was associated with a 60% survival rate. Sixty-three percent of infants whose best postductal PaO2 value before ECMO was less than 100 torr survived, and 7 of 11 infants with a best postductal PaO2 value of less than 50 torr before ECMO survived (64%). The average age at surgery progressively increased over time both for infants who did not require ECMO (1.3 days to 5.8 days; P = .01) and for infants who received ECMO (1.9 days to 8.2 days; P = .016). CONCLUSIONS: The use of a protocolized management for infants with CDH has been associated with improving outcome in a population at high risk. The components (either separately or combined) of these protocolized approaches need to be tested in prospective trials to determine their true benefit. In addition, there is a need to evaluate prospectively the outcomes of infants with CDH born in ECMO centers compared with those infants born in other tertiary care neonatal units to determine the most appropriate management of the fetus with CDH. 相似文献