对讲机微波辐射强度的调查分析

目的　对 2个品牌 4种型号的对讲机微波辐射进行测定研究。方法　使用已校正的国产ML 91型微波漏能测试仪 ,测定 4种型号 199台对讲机的微波辐射强度。结果　发射状态下距离对讲机天线部 5cm处和各部位 5cm处微波漏能平均功率密度分别为 (1316 .0± 14 4 .3)、(971.0± 131.6 )μW/cm2 ,均明显高于待机状态 [分别为 (14 .4± 5 .3)、(13.2± 4 .9) μW/cm2 ],差异有显著性 (P <0 .0 1)。在发射状态下距离对讲机不同部位 5 0cm处微波漏能平均功率密度为 (35 7.3± 2 7.8) μW/cm2 。 4种型号对讲机在发射通话状态下 ,对持机者的头、胸、腹部接触微波漏能平均功率密度日总计量为(94 5 .5±4 4 7.1) μW·h/cm2 ,超过国家作业场所微波辐射卫生标准的日总计量 (40 0 μW·h/cm2 )。结论　对讲机在发射状态的微波漏能明显高于待机状态。对讲机微波漏能以天线部最高。对讲机在发射状态 ,对持机者的头、胸、腹部微波漏能大部分超过国家作业场所微波辐射卫生标准 ,对持机者健康可造成潜在的影响 ,应做好防护工作。     

几种常用电器的极低频磁场水平的分析

近年来 ,各国科学家进行了多项有关极低频磁场 (ex tremelylowfrequencymagneitcfield ,ELFMF)与恶性肿瘤关系的流行病学调查认为ELFMF有可能导致肿瘤发生率增高。在我们日常生活中所使用的各种电器都能产生ELFMF ,从而有可能对人体的健康产生危害。我们调查了日常生活中接触机会较多、使用时间相对较长的数种家用电器的ELFMF水平。一、对象与方法1 测定对象 :各种品牌纯平彩色电视机 5 0台、等离子彩色电视机 10台、背投彩色电视机 10台、家用微波炉 15台、冰箱 10台以及复印机 10台。2 测定仪器 :ElectromagneticFieldTester(M…     

电脑的电磁辐射对人体健康的影响

随着电脑的日益普及,从70年代末以来人们开始关心电脑的电磁辐射对人体健康有无不良影响。电脑的电磁辐射来自视频终端显示器的阴极射线管,它能发射出软X线、紫外线、红外线、可见光以及射频、高频和低频电磁辐射。软X线在离屏幕5cm处的剂量为0～0.2mR/h(容许剂量是0.5mR     

金属隔室作业场所工人微波辐射的暴露水平

目的　研究金属隔室作业场所微波辐射暴露水平及其防护技术。方法　按GB10 4 36 89测试方法 ,测定药品生产车间改造前用混凝土砖墙和改造后用金属板材料建造的微波隔室作业场所的漏能情况 ,评价其暴露水平及辐射控制效果。结果　作业场所改造前、后距场源 10cm处漏能平均值分别为 6 0 6 .0、10 33.0 μW/cm2 ,距场源 10 0cm处平均值分别为 79.8、5 2 .3μW/cm2 ,距场源 15 0～ 5 0 0cm处平均值分别为9.3、2 0 .5 μW/cm2 。2种不同屏蔽环境作业场所工人作业范围微波辐射暴露水平差异不大 ,漏能衰减与场源距离关系较大。场源屏蔽所采取的技术不完善 ,漏能控制效果不佳。结论　以金属材料封闭隔室的微波作业场所辐射暴露水平及防护控制问题应引起重视。     

MS2和T4噬菌体对短波紫外线抵抗力的比较研究

[目的]观察MS2和T4两种噬菌体对短波紫外线(UVC)抵抗力的变化,确定不同强度UVC有效灭活两种噬菌体的时间,为寻找最适噬菌体作指示病毒用于UVC灭活病毒效果的评价提供依据。[方法]噬菌体悬液在一定紫外线强度下照射不同的时间,最后采用双层琼脂平板法分别测定照射前后的噬菌体滴度,绘制照射前后噬菌体的灭活曲线(t-Δlog),并在不同紫外线强度下进行测定。[结果]MS2噬菌体在UVC照射下:370 μW/cm2,10min,或680 μW/cm2,5min,或1130 μW/cm2,3min,达到消毒水平(LIV≥4.00log10),LIV分别为4.49 log10、4.52 log10和4.16 log10;T4噬菌体则为370 μW/cm2,20min,或680 μW/cm2,15min,或1130 μW/cm2,5min,达到消毒水平,LIV分别为4.60 log10,4.02 log10和5.46 log10。[结论]在本实验条件下,对短波紫外线的抵抗力:T4噬菌体﹥MS2噬菌体。     

广州市孕妇硒碘营养状况调查

目的　了解广州市孕妇孕中、晚期硒碘营养状况。方法　用砷铈接触法测定尿碘 ,用放射免疫分析法(RIA)测定血清甲状腺素 (T4)、促甲状腺激素 (TSH) ,荧光光度法测定静脉全血硒。结果　孕中期血硒含量 (0 1375± 0 0 96 9) μg/ml及孕晚期血硒含量 (0 15 2 8± 0 0 85 9) μg/ml,远低于我国中硒区成人血硒值 (0 35± 0 0 2 ) μg/ml。孕中、晚期血硒含量无明显变化 (P >0 0 5 )。孕中期尿碘中位数为 2 4 9 3μg/L ,<10 0 μg/L者占 4 5 % ;孕晚期尿碘中位数为 2 4 1 2 μg/L ,<10 0 μg/L者占 12 5 % ,两期尿碘值自身比较差异无统计学意义 (P >0 0 5 )。孕中期血清T 4(15 7 0± 6 6 4 )nmol/L ,在正常范围者占 5 8 2 % ;孕晚期血清T4(12 4 4± 5 9 4 )nmol/L ,在正常范围者占 78 3%。孕中期血清TSH(中位数 3 9mU/L) >5mU/L者占 34 3% ,孕晚期血清TSH (中位数 6 9mU/L) >5mU/L者占81 8%。中晚期自身比较TSH >5mU/L与 >5mU/L的人数构成差异有统计学意义 (P <0 0 1)。结论　广州市孕妇硒碘营养状况良好 ,孕晚期血清TSH >5mU/L者 (81 8% )较多 ,与尿碘、T4水平不一致 ,有待进一步研究。     

局部振动对家兔外周血中脂质过氧化的影响

[目的 ]探讨局部振动对家兔脂质过氧化的影响。 [方法 ]将家兔随机分为低强度组 (接振强度 3 .0 3m/s2 ) ,中强度组 (接振强度 6.13m/s2 ) ,高强度组 (接振强度 12 .2 5m/s2 )和 1个对照组 ,分别于接振 10、2 0、3 0d测定各组家兔血中MDA浓度、SOD活力和GSH Px活力。 [结果 ]接振后 10、2 0、3 0d的MDA浓度分别为 :低强度组 ( 3 .77± 0 .3 4) μmol/L、( 4 .16± 0 .3 0 ) μmol/L、( 4 .3 9± 0 .3 1) μmol/L ;中强度组 ( 4 .12± 0 .3 5 ) μmol/L、( 4 .3 8± 0 .3 4) μmol/L、( 4 .5 4± 0 .42 ) μmol/L ;高强度组 ( 4 .13± 0 .3 2 ) μmol/L、( 4 .5 8± 0 .47) μmol/L、( 4 .99± 0 .70 ) μmol/L。SOD活力分别为 :低强度组 ( 82 994± 10 70 1)U/L、( 86113± 860 2 )U/L、( 8873 7± 75 48)U/L ;中强度组 ( 880 5 0± 9196)U/L、( 915 13± 7114 )U/L、( 93 60 8± 8842 )U/L ;高强度组 ( 895 5 3± 12 677)U/L、( 942 46± 14 480 )U/L、( 963 19± 13 981)U/L。GSH Px活力分别为 :低强度组 ( 780 4± 846)U/L、( 82 5 9± 414 )U/L、( 842 7± 2 90 )U/L ;中强度组 ( 82 11± 765 )U/L、( 8465± 462 )U/L、( 90 76± 75 3 )U/L ;高强度组 ( 8984± 63 9)U/L、( 93 0 2± 62 5 )U/L、(     

近视与眼调节反应时间关系的研究

目的　探索不同注视时间后近视的调节反应时间。　方法　 2台显示器 ,分别用于视远 (5m )和视近 (0 .3m)。一台显示器上的注视视标消失时 ,另一台显示器上的视标立刻出现并持续一定时间。受试者先注视一台显示器上的视标 ,该视标消失时努力看清另一台显示器上视标需要的时间为调节反应时间。　结果　正视眼与早发性近视眼的远调节反应时间 (4 77、488ms)比近调节反应时间 (3 76、3 71ms)长 (P <0 .0 1)。注视近视标 60s后 ,早发性近视眼远调节反应时间 (691ms)的延长与正视眼的远调节时间 (678ms)的延长相比没有显著性差异 (P >0 .0 5 )。　结论　远调节比近调节慢 ,远调节反应时间延长与早发性近视可能没有明显相关性。     

局部振动对家兔血清肿瘤坏死因子浓度的影响

目的　探讨局部振动对肿瘤坏死因子 (tumornecrosisfactor,TNF)的影响及其意义。方法　将家兔随机分为A组 (接振强度 3.0 3m s2 ,每天接振 0 .5h)、B组 (接振强度 6 .13m s2 ,每天接振 1h)、C组 (接振强度 12 .2 5m s2 ,每天接振 1h)和 1个对照组 (D组 )。各接振组均进行 30d接振试验。分别于试验前、试验第 10、2 0、30天对各组家兔进行血清TNF浓度的测定及分析。结果　在试验前及试验第 10、2 0、30天 ,A组TNF浓度分别为 (3.10± 0 .39)、(3.2 7± 0 .5 8)、(3.79± 0 .5 1)、(4 .16±0 .31) μg L ,B组分别为 (3.16± 0 .4 9)、(3.5 7± 0 .4 3)、(4 .14± 0 .6 9)、(4 .4 8± 0 .4 7) μg L ,C组分别为(3.2 1± 0 .37)、(3.91± 0 .5 0 )、(4 .4 6± 0 .5 9)、(4 .88± 0 .5 4 ) μg L ,D组分别为 (3.2 4± 0 .5 8)、(3.36±0 .6 9)、(3.33± 0 .6 1)、(3.19± 0 .39) μg L。与试验前和实验相同时间对照组比较 ,接振组家兔血清TNF浓度呈增高趋势 ,且差异均有显著性 (P <0 .0 5 ,P <0 .0 1)。结论　局部振动所导致血清中TNF浓度的变化可能与振动病的发病机制有一定关系。     

铅对大鼠脑组织神经生长因子表达的影响及甲状腺激素的调节作用

目的　研究醋酸铅对大鼠脑组织神经生长因子 (NGF)表达的影响及甲状腺激素的调节作用。方法　对SD大鼠用 2 5、5 0、10 0mg/kg体重的醋酸铅腹腔注射 ;用丙基硫氧嘧啶 (PTU)制作甲状腺机能减退大鼠模型 ,再给予 5 0mg/kg体重的醋酸铅 ,分别以免疫组化测定脑组织中NGF蛋白的表达。以放射免疫方法测定血清中三碘甲状腺原氨酸 (T3 )、甲状腺素 (T4)、促甲状腺激素 (TSH)的含量及脑组织中T3 、T4的含量。结果　中、高剂量组皮层组织NGF平均灰度 (180 .4 9± 10 .33、16 9.72±19 .75 )与对照组 (2 0 0 .75± 3.2 7)相比 ,差异有显著性 (P <0 .0 1) ;各剂量组海马组织NGF面密度 (0 .0 8± 0 .14、0 .12± 0 .0 2、0 .13± 0 .0 4 )与对照组 (0 .0 2 5± 0 .0 15 )相比 ,差异有显著性 (P <0 .0 5 )。甲状腺机能减退后再用醋酸铅处理 ,皮层、海马组织NGF面密度和平均灰度未见明显改变。各剂量染铅组大鼠血清中T3 [(0 .6 8± 0 .0 2 )、(0 .5 7± 0 .0 4 )、(0 .5 4± 0 .0 2 ) μg/L]和T4[(2 8.30± 1.83)、(2 7.35± 2 .5 5 )、(2 4 .0 0± 3.0 1) μg/L]含量明显下降 ,而TSH[(6 .34± 1.13)、(7.74± 0 .79)、(9.16± 0 .77)IU]增高 ,与对照组T3 [(0 .97± 0 .14 ) μg/L]、T4[(5 4 .5 0± 3.70 ) μg/L]和TSH     

Breast cancer, occupation, and exposure to electromagnetic fields among Swedish men

BACKGROUND: Investigations of breast cancer among men may provide clues for environmental and occupational risk factors that may be difficult to study in women, because of confounding or effect modification from reproductive female characteristics. The objective was to estimate occupation-specific risks of male breast cancer and to assess the effect of occupational exposure to extremely low-frequency magnetic fields (ELFMF). METHODS: Standardized incidence ratios were computed for the period 1971-1989 among Swedish men who were 25-59 years of age at start of follow-up and gainfully employed in 1970. Log-linear Poisson models were fitted to adjust for geographical area. A job exposure matrix was used to classify occupational ELFMF exposure. RESULTS: A marked and consistent excess risk was found for machinery repairers. Increased relative risks based on few cases were also noted for librarians/archivists/curators, bank employees, non-specified clerical workers, metal processing workers, tanners/fur dressers, policemen, and custom surveillance officials. The relative risk among subjects with an estimated ELFMF exposure above the first quartile (0.12 microT) was 1.31 (95% confidence interval = 0.94-1.81), without a clear exposure-response pattern. Indications of an exposure-response relationship were found in workers with intermittent ELFMF exposure. CONCLUSIONS: The findings give no clear evidence for an etiological role of ELFMF in the development of breast cancer in men, but suggest that large variations in exposure over the work-day may be associated with an increased risk.     

高等真核细胞受极低频磁场辐照后基因差异表达的分析

目的　从基因水平研究电磁场的非热效应及其可能的机制。方法　以高等真核细胞（ 人恶性淋巴瘤细胞） 为模型,运用ｍ ＲＮＡ 差异显示法（ｍ ＲＮＡ ｄｉｆｆｅｒｅｎｔｉａｌ ｄｉｓｐｌａｙ ,ＤＤ） 技术分析受５０ Ｈｚ 极低频磁场（ＥＦＬＭＦ） 辐照及假辐照２４ 小时后的细胞基因转录的差异。结果　用７５ 个引物组合获得１１个对ＥＬＦＭＦ 显示差异反应的ｃＤＮＡ 片段,表现为：（１） 片段只出现在受辐照的细胞,而未出现在非辐照的细胞中;（２） 片段只出现在非辐照的细胞中,而未出现在受辐照的细胞中;（３） 片段在辐照和非辐照细胞中均有表达,但表达强度有明显差异。回收这些片段,经ＰＣＲ 重扩增及反向Ｎｏｒｔｈｅｒｎ 初步筛选,结合Ｎｏｒｔｈｅｒｎ ｂｌｏｔ 鉴定,部分ｃＤＮＡ 得到证实为磁场特异反应基因。结论　低强度ＥＬＦＭＦ 可影响基因表达。     

Long-term exposure to a magnetic field (5 mT at 60 Hz) increases X-ray-induced mutations.

Exposure to extremely low frequency magnetic field (ELFMF) at 400 mT has been shown to induce mutations (Mutat. Res., 349: 109-114, 1996; Int. J. Radiat. Biol., 71: 75-79, 1997; and Biochem. Biophys. Res. Commun., 243: 579-584, 1998). However, whether ELFMF at low flux densities (under 1 mT) induces mutations is debatable. We investigated the effect of long-term exposure to 5 mT ELFMF at 60 Hz on mutant frequency. Chinese hamster ovary K1 (CHO-K1) cells were exposed or sham-exposed to 5 mT ELFMF for up to 6 weeks with or without X-irradiation (3 Gy), and the mutant frequency of the hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene was analyzed. Long-term exposure to 5 mT ELFMF did not increase mutations, suggesting a threshold for mutation induction greater than 115 mA/m2 or a magnetic density of 5 mT. However, enhancement of the X-ray-induced mutation rate was observed after treatment with X-irradiation followed by long-term exposure to 5 mT ELFMF. At little as a 1-week exposure to ELFMF after X-irradiation enhanced the mutation rate. We also found that 400 mT exposure enhanced the mutation rate induced by X-irradiation (Mutat. Res., 349: 109-114, 1996). These results suggest that exposure to more than 5 mT ELFMF may promote X-ray-induced mutations.     

Exposure to strong magnetic fields at power frequency potentiates X-ray-induced DNA strand breaks

We examined the effect of an extremely low-frequency magnetic field (ELFMF) at 5, 50 and 400 mT on DNA strand breaks in human glioma MO54 cells. A DNA damage analysis was performed using the method of alkaline comet assay. The cells were exposed to X-rays alone (5 Gy), ELFMF alone, or X-rays followed by ELFMF at 4 degrees C or on ice. No significant difference in the tail moment was observed between control and ELFMF exposures up to 400 mT. X-ray irradiation increased DNA strand breaks. When cells were exposed to X-rays followed by ELFMF at 50 and 400 mT, the tail moment increased significantly compared with that for X-rays alone. When the exposure of cells was performed at 37 degrees C, no significant change was observed between X-rays alone and X-rays plus 400 mT. We previously observed that exposure to 400 mT ELFMF for 2 h increased X-ray-induced mutations (Miyakoshi et al, Mutat. Res., 349: 109-114, 1996). Additionally, an increase in the mutation by exposure to the ELFMF was observed in cells during DNA-synthesizing phase (Miyakoshi et al., Int. J. Radiat. Biol., 71: 75-79, 1997). From these results, it appears that exposure to the high density ELFMF at more than 50 mT may potentiate X-ray-induced DNA strand breaks.     

基于计量检测数据的除颤监护仪性能对比研究

目的:分析对比两种型号除颤监护仪的性能差异,为临床使用及设备管理提供数据支持.方法:选取医院2016-2020年在用的两种型号除颤监护仪各5台,依据型号的不同将其分别定义为除颤监护仪A(5台)和除颤监护仪B(5台),利用因果分析法分析两种型号除颤监护仪的故障因素及计量检测数据.采用SPSS分析软件对两种型号除颤监护仪2...     

Estimation of high-level, rapidly-changing concentrations using moving-filter continuous particulate air monitors

A previously published mathematical model for the dynamic response of moving-filter continuous particulate air monitors has been enhanced to extend that model to include decay chains. During this work, it was observed that a quantitative relationship appeared to exist between the monitor count rate and the time-dependent particulate airborne radioactive material concentration if, and only if, the filter (tape) speed was much faster than the nominal 2.54 cm h(-1) (1 in h(-1)). The extended model demonstrated that operating moving-filter monitors at this nominal filter speed does not provide a quantitative measurement of a changing airborne particulate concentration of a fission product or other contaminant. By contrast, at faster filter speeds [e.g., 76.2 or 152.4 cm h(-1) (30 or 60 in h(-1))], numerical experimentation with this model showed that the count rate trace has essentially the same shape as the concentration profile. It was then found that a quantitative relationship applies, but only when the filter speed is sufficiently fast so that a Taylor series expansion of the monitor count rate can be reasonably well truncated at the first-order term. This mode of operation, which does not require any new monitor hardware, is capable of tracking rapidly changing concentrations. Since the fast filter speed also reduces the monitor's count rate, all else being equal, the approach will best be used for relatively high-level concentrations, such as may occur in abnormal or "accident" conditions. The count rate suppression may also be useful for reducing the detector saturation that can occur with higher levels of airborne particulate radioactivity in post-accident situations.     

基于紫蜂技术的高压氧舱专用生理监护仪的研制

介绍一种基于无线传感器网络的多生理参数监护仪。该监护仪专门应用于高压氧舱内监护,可以监测心电、血压、血氧饱和度、呼吸、温度五种参数。多参数信号经采集转换后在舱内监护终端(分机)液晶屏上显示,同时通过紫蜂(Zigbee)无线发送模块将信号传输到舱外中央监护PC终端(主机)上,实现舱内、舱外同步实时监测,一台主机可同时显示三个分机的监测数据。初步临床试用表明,该监护仪使用安全,效果理想。     

Assessment of exposure to magnetic fields in occupational settings

OBJECTIVE: It is important to have data about occupational magnetic field intensity to consider the contribution of occupational magnetic field exposure on the human body. We conducted research on exposure to occupational magnetic fields and tried to qualify data on the distribution of magnetic field' intensity in certain general working environments with individual measurements. SUBJECTS AND METHODS: We performed sample research on the exposure to low-frequency magnetic fields of workers in certain occupations and in the working environment. We also assessed the relationship between working environmental magnetic field distribution and individual exposure. RESULTS: Some occupations were found to be exposed to high magnetic fields. We observed that some workspaces, such as the transformer substation, generally had a uniform and high magnetic field measurement but employees were exposed to a lower intensity. We also found that welders were exposed to high magnetic fields at about 600 microT in a very short time but with a geometrical value of 0.08 microT. CONCLUSION: The determination of administrative levels and control levels, not only of the time weighted average of threshold limits or short term exposure limits, but also ceiling limits should be considered. More systematic research is necessary to determine variables such as operating conditions, measuring position, and frequency bands. Also, further studies will be needed to make a job-exposure matrix for the magnetic fields for each occupation type and to combine it with exposure in non-occupational settings such as commuting and ordinary life situations to explore the causal relationship between exposure to magnetic fields and disease.     

Identification of factors that disrupt negative air pressurization of respiratory isolation rooms.

OBJECTIVES: To investigate the airflow characteristics of respiratory isolation rooms (IRs) and to evaluate the use of visible smoke as a monitoring tool. METHODS: Industrial hygienists from the New York State Department of Health evaluated 140 designated IRs in 38 facilities within New York State during 1992 to 1998. The rooms were located in the following settings: hospitals (59%), correctional facilities (40%), and nursing homes (1%). Each room was tested with visible smoke for directional airflow into the patient room (ie, negative air pressure relative to adjacent areas). Information was obtained on each facility's policies and procedures for maintaining and monitoring the operation of the IRs. RESULTS: Inappropriate outward airflow was observed in 38% of the IRs tested. Multiple factors were associated with outward airflow direction, including ventilation systems not balanced (54% of failed rooms), shared anterooms (14%), turbulent airflow patterns (11%), and automated control system inaccuracies (10%). Of the 140 tested rooms, 38 (27%) had either electrical or mechanical devices to monitor air pressurization continuously. The direction of airflow at the door to 50% (19/38) of these rooms was the opposite of that indicated by the continuous monitors at the time of our evaluations. The inability of continuous monitors to indicate the direction of airflow was associated with instrument limitations (74%) and malfunction of the devices (26%). In one facility, daily smoke testing by infection control staff was responsible for identifying the malfunction of a state-of-the-art computerized ventilation monitoring and control system in a room housing a patient infectious with drug-resistant tuberculosis. CONCLUSION: A substantial percentage of IRs did not meet the negative air pressure criterion. These failures were associated with a variety of characteristics in the design and operation of the IRs. Our findings indicate that a balanced ventilation system does not guarantee inward airflow direction. Devices that continuously monitor and, in some cases, control the pressurization of IRs had poor reliability. This study demonstrates the utility of using visible smoke for testing directional airflow of IRs, whether or not continuous monitors are used. Institutional tuberculosis control pro grams should include provisions for appropriate monitoring and maintenance of IR systems on a frequent basis, including the use of visible smoke.     

Weak electromagnetic fields (50 Hz) elicit a stress response in human cells

The aim of this study was to demonstrate the expression of heat shock (HS) genes in human cells in response to extremely low-frequency electromagnetic fields (ELF-EMF) alone and in combination with thermal stress. After exposing human myeloid leukemia (HL-60) cells to the stressor(s) for 30 min we quantified the expression of the HS genes HSP27, HSP60, HSP70 (A, B, and C), HSC70, HSP75, HSP78, and HSP90 (alpha and beta) by RT-PCR. The results clearly show that HS genes, in particular the three HSP70 genes (A, B, and C), are induced by ELF-EMF, a reaction that is enhanced by simultaneous HS (43 degrees C for 30 min). The results show similarities and some significant differences to previous experiments in which transgenic nematodes were used to monitor the induction of the HSP70 gene under similar stress conditions. We also studied the effect of different flux densities on gene expression in the range of 10-140 microT. Even the lowest dose tested (10 microT) resulted in a significant induction of the genes HSP70A, HSP70B, and HSP70C. The reaction to ELF-EMF shows a maximum at a flux density of 60-80 microT. The unusual dose-response relation reveals an interesting difference to other stressors that elicit the HS response.