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961.
刘立喜 《北京生物医学工程》2011,30(4):415-416,419
动物实验室净化空调系统的运行节能非常重要.本文通过分析动物实验室夏、冬两季的主要能耗特点,借鉴焓湿图和能耗公式对比得出了夏季、冬季的具体节能措施. 相似文献
962.
Isabelle R. Miousse Marie‐Cécile G. Chalbot Nükhet Aykin‐Burns Xiaoying Wang Alexei Basnakian Ilias G. Kavouras Igor Koturbash 《Environmental and molecular mutagenesis》2014,55(5):428-435
Respiratory mortality and morbidity has been associated with exposure to particulate matter (PM). Experimental evidence suggests involvement of cytotoxicity, oxidative stress, and inflammation in the development of PM‐associated pathological states; however, the exact mechanisms remain unclear. In the current study, we analyzed short‐term epigenetic response to PM10 (particles with aerodynamic diameter less than 10 μm) exposure in mouse ascitic RAW264.7 macrophages (BALB/C Abelson murine leukemia virus‐induced tumor). Ambient PM10 was collected using a high volume sampler in Little Rock, AR. Analysis revealed that PM10 was composed mainly of Al and Fe, and the water soluble organic fraction was dominated by aliphatic and carbohydrate fragments and minor quantities of aromatic components. Exposure to PM10 compromised the cellular epigenome at concentrations 10–200 µg/ml. Specifically, epigenetic alterations were evident as changes in the methylation and expression of repetitive element‐associated DNA and associated DNA methylation machinery. These results suggest that epigenetic alterations, in concert with cytotoxicity, oxidative stress, and inflammation, might contribute to the pathogenesis of PM‐associated respiratory diseases. Environ. Mol. Mutagen. 55:428–435, 2014. © 2014 Wiley Periodicals, Inc. 相似文献
963.
Andries W. Pienaar Justhinus G. Barnard 《Journal of medical engineering & technology》2017,41(3):216-222
This study describes the development of a new portable muscle testing device, using air pressure as a biofeedback and strength testing tool. For this purpose, a pressure air biofeedback device (PAB®) was developed to measure and record the isometric extension strength of the lumbar multifidus muscle in asymptomatic and low back pain (LBP) persons. A total of 42 subjects (age 47.58 years, ±18.58) participated in this study. The validity of PAB® was assessed by comparing a selected measure, air pressure force in millibar (mb), to a standard criterion; calibrated weights in kilograms (kg) during day-to-day tests. Furthermore, clinical trial-to-trial and day-to-day tests of maximum voluntary isometric contraction (MVIC) of L5 lumbar multifidus were done to compare air pressure force (mb) to electromyography (EMG) in microvolt (μV) and to measure the reliability of PAB®. A highly significant relationship were found between air pressure output (mb) and calibrated weights (kg). In addition, Pearson correlation calculations showed a significant relationship between PAB® force (mb) and EMG activity (μV) for all subjects (n?=?42) examined, as well as for the asymptomatic group (n?=?24). No relationship was detected for the LBP group (n?=?18). In terms of lumbar extension strength, we found that asymptomatic subjects were significantly stronger than LBP subjects. The results of the PAB® test differentiated between LBP and asymptomatic subject’s lumbar isometric extension strength without any risk to the subjects and also indicate that the lumbar isometric extension test with the new PAB® device is reliable and valid. 相似文献
964.
Water treatment plant (WTP) sludge is actively used in building materials production. The object of this research was modifying additives for ceramic bricks from WTP aluminium-containing sludge. The research aim of this study was to determine the suitability of a million-plus population city’s WTP sludge as a burning-out additive in the production of structural ceramics and to establish the optimal conditions for obtaining products with the best characteristics. The raw water belongs to water belongs to the hydrocarbonate class, the calcium group, and it is of low turbidity (1.5–40 mg/L kaolin). Sludge, sourced from WTP sedimentation tanks, was dewatered by adding lime or by using the freezing-thawing method. The spray-dried WTP sludge is introduced into the clay in amounts of 5% to 20% by weight. The addition of 20% reduces the sensitivity of the clay to drying, reduces the density of ceramic by 20% and simultaneously increases its compressive strength from 7.0 to 10.2 MPa. The use of WTP sludge as a modifying additive, pretreated by the freezing-thawing method, makes it possible to obtain ceramic bricks with improved properties. The results can be used for WTP sludge containing aluminium obtained by treating water of medium turbidity and medium colour. 相似文献
965.
Abstract
Background
Air pollution is associated with significant increases in cardiac morbidity and mortality in the general population. The elderly
cohort within the general population is considered at high risk for cardiac diseases. However the degree to which air pollutants
affect cardiac responses in old hearts vs. their young adult counterparts has not been systematically addressed.
Objectives
We sought to investigate the response of young adult vs. old rat hearts to the direct exposure of ultrafine particles (UFP); i.e. when the UFP are directly instilled into the
cardiac vasculature, and their effects are not dependent upon UFP inhalation.
Methods
The study was performed in isolated Langendorff-perfused rat hearts obtained from young adult (4 months old) and aged (26
months old) Fisher 344/Brown Norway rats. Two treatment groups (control and UFP-treated) were studied, and two ages (young
adult and old) were studied within each group. Control hearts were perfused with buffer only, UFP-treated hearts were perfused
with buffer containing ultrafine particles isolated from industrial diesel reference particulate matter. Systolic and end-diastolic
pressures, positive and negative dP/dt, and coronary flow were measured.
Results
Young adult and old hearts demonstrated equal functional deterioration in response to direct infusion of UFP. Developed pressure
in young adult UFP-treated hearts fell from 101±4 to 68±8 mmHg (a decrease by 33%, p<0.05). In the old UFP-treated hearts
developed pressure fell by 35% (from 101±7 to 67±9mmHg, p<0.05). Positive dP/dt was equally affected in the young adult and
old UFP-treated hearts and was decreased by 28% in both groups.
Conclusion
Ultrafine particles when instilled directly into the cardiac vasculature were equally cardiotoxic in young adult and old rat hearts. 相似文献
966.
目的了解宜兴市新装修居室室内空气污染水平和分布状况,研究居室装修对室内空气质量的影响,为有效防治室内空气污染提供科学依据。方法依据《室内空气质量标准》(GB/T 18883—2002),采用酚试剂法测定甲醛,气相色谱法测定总挥发性有机物(TVOC)。结果宜兴市2012年-2016年室内空气中甲醛的超标率达17.76%,最大检出浓度超过国家标准5倍以上,TVOC的超标率达65.88%,最大检出浓度超过国家标准15倍以上。各种污染物的超标率均为豪华装修﹥中档装修﹥简单装修。客厅墙面材质的不同,对室内空气中污染物的影响没有明显特征。进家具前后污染物浓度差异有统计学意义(P<0.05)。结论宜兴市室内空气中各种污染物的超标情况严重,并且未见逐年降低趋势,装修工艺、材料、家具、装修后时间等是影响室内空气污染物浓度的主要因素。 相似文献
967.
Background
Several studies suggest that airborne particulate matter (PM) is associated with infant mortality; however, most focused on short-term exposure to larger particles.Objectives
We evaluated associations between long-term exposure to different sizes of particles [total suspended particles (TSP), PM ≤ 10 μm in aerodynamic diameter (PM10), ≤ 10–2.5 μm (PM10–2.5), and ≤ 2.5 μm (PM2.5)] and infant mortality in a cohort in Seoul, Korea, 2004–2007.Methods
The study includes 359,459 births with 225 deaths. We applied extended Cox proportional hazards modeling with time-dependent covariates to three mortality categories: all causes, respiratory, and sudden infant death syndrome (SIDS). We calculated exposures from birth to death (or end of eligibility for outcome at 1 year of age) and pregnancy (gestation and each trimester) and treated exposures as time-dependent variables for subjects’ exposure for each pollutant. We adjusted by sex, gestational length, season of birth, maternal age and educational level, and heat index. Each cause of death and exposure time frame was analyzed separately.Results
We found a relationship between gestational exposures to PM and infant mortality from all causes or respiratory causes for normal-birth-weight infants. For total mortality (all causes), risks were 1.44 (95% confidence interval, 1.06–1.97), 1.65 (1.18–2.31), 1.53 (1.22–1.90), and 1.19 (0.83–1.70) per interquartile range increase in TSP, PM10, PM2.5, and PM10–2.5, respectively; for respiratory mortality, risks were 3.78 (1.18–12.13), 6.20 (1.50–25.66), 3.15 (1.26–7.85), and 2.86 (0.76–10.85). For SIDS, risks were 0.92 (0.33–2.58), 1.15 (0.38–3.48), 1.42 (0.71–2.87), and 0.57 (0.16–1.96), respectively.Conclusions
Our findings provide supportive evidence of an association of long-term exposure to PM air pollution with infant mortality. 相似文献968.
BACKGROUND: Ozone is a potent photochemical oxidant that produces transient, reversible decrements in the lung function of acutely exposed individuals. A recent study provided previously unavailable clinical data for 30 healthy young adults exposed to O(3) at 0.06 ppm. That study showed significant effects of 0.08 ppm on lung function, confirming the findings of others. However, exposure to 0.06 ppm O(3) was not reported to significantly affect lung function. OBJECTIVES: We conducted this analysis to reevaluate the existing lung function data of the volunteers previously exposed to 0.06 ppm O(3). METHODS: We obtained pre- and postexposure data on forced expiratory volume in 1 sec (FEV(1)) for all subjects who were previously exposed for 6.6 hr to filtered air or to 0.06 ppm or 0.08 ppm O(3). We used standard statistical methods appropriate for paired comparisons to reanalyze FEV(1) responses after exposure to 0.06 ppm O(3) relative to filtered air. RESULTS: Controlling for filtered air responses, 24 of the 30 subjects experienced an O(3)-induced decrement in FEV(1). On average, 0.06 ppm O(3) exposure caused a 2.85% reduction in FEV(1) (p < 0.002), which was consistent with the predicted FEV(1) response from existing models. Although the average response was small, two subjects had > 10% FEV(1) decrements. CONCLUSIONS: Exposure to 0.06 ppm O(3) causes a biologically small but highly statistically significant decrease in mean FEV(1) responses of young healthy adults. 相似文献
969.
上海市地铁车站空气污染监测分析 总被引:1,自引:0,他引:1
[目的]了解上海轨道交通系统4个月份空气中主要污染物的污染状况,为疾病预防、卫生监督等工作的开展提供科学依据及合理建议。[方法]分别选取上海市轨道交通具有代表性的6个车站,每个车站分站台、站厅共取8个点进行监测。于2009年5月、7月、11月及2010年1月4个月份分别连续监测3个工作日,每日3个时段。在每个监测点监测可吸入颗粒物(PM10)、二氧化碳(CO2)、空气细菌总数、真菌总数、溶血性链球菌等空气卫生学指标。同时对相应的新风量进行测定。[结果]上海市地铁的地下车站细菌总数及CO2浓度年超标率均高于地上车站。地下车站PM。。浓度在1月份及11月份超标率分别为4.13%、3.13%;地上车站PM10浓度在1月份超标率为1.75%。地上车站细菌总数在7月份为(30.1±7.7)个/皿,显著高于其他监测月份;真菌总数在1月份最低,为(9.4±1.2)个/皿,显著低于其他月份;PM,。浓度在1月份为(0.161±0.001)mg/m^2,高于其他监测月份,且差异具有统计学意义(P〈0.05)。地下站细菌总数在5月份为(21.5±4.1)个/皿,显著低于其他各月份;真菌总数在5月份为(13.6±1.6)个/皿,显著低于其他月份,在7月份为(37.1±8.6)个/皿,显著高于其他月份;PM10浓度在1月份高于其他月份,为(0.168±0.003)mg/m^2,且差异具有统计学意义(P〈0.05)。CO2浓度未见季节性差异;溶血性链球菌只有在11月份的监测中检出1例,检出率为0.049%。[结论]上海市轨道交通系统车站PM10在1月份污染严重,地下站微生物超标现象较地上站严重。 相似文献
970.
新装修居室内甲醛污染检测结果分析 总被引:1,自引:0,他引:1
[目的 ]分析新装修居室内甲醛污染状况及特点 ,探讨室内甲醛浓度随装修完工后时间长短的变化规律。 [方法 ]检测分析厦门市区 10 1套居室的 3 91个采样点装修后室内空气中的甲醛浓度。[结果 ]在这些采样点中 ,空气甲醛浓度>0 10mg/m3 的超标者占 68 0 %,超标 2倍以上者 3 1 2 %;套房内空气甲醛浓度均值为书房 >卧室 >客厅 ;空气甲醛浓度的峰值不是出现在装修完工后的初期 ( 1个月内 ) ,而是出现在更后些时间段 ( 2~ 3个月 )。[结论 ]新装修居室的室内甲醛污染状况较为严重 (尤其是头 3个月 ) ,装修完 1年内都应注意室内的通风换气 ,以降低室内空气中的甲醛浓度 相似文献