本溪钢铁公司矿山天然放射性水平研究

本溪钢铁公司矿山天然放射性水平研究井春岩，张志兴联合国原子辐射效应科学委员会（ＵＮＳ－ＣＥＡＲ）１９８２年报告指出（ｌ），天然辐射源对居民产生的年有效剂量当量为２．４ＶＳｙ．其中，外照射为０．ｓｍｓｖ，内照射为１．６ｍｓ、。因此，对天然放射性水平进行...     

山东省地热水中放射性水平的测定与卫生学评价

地热水是从地下深层自然涌出地表或人工钻孔提取的地下热水,已被广泛应用多个领域.近年来山东省探明的地热资源位居全国之首,但有些地热水中放射性核素活度水平较高,地热水的大量开采将对环境造成污染.为掌握山东省地热水中放射性核素浓度水平,我们对近年来送检的地热水样品进行放射性核素分析测定并进行卫生学评价,报道如下.     

煤渣天然放射性与所建房内γ辐射水平

煤渣天然放射性与所建房内γ辐射水平李增祥为了探讨煤渣砖天然放射性与之用于建造房屋室内γ辐射的相关关系和对居住者的健康影响，作者于１９９０年～１９９１年按统一方法对此进行了调查研究，现报告于下：本次调查选择我市有代表性的煤渣生产厂（场）为对象，对所产的...     

贵州省瓮福磷矿区放射性水平

瓮福磷矿位于贵州省瓮安县福泉市境内，是全国最大的磷矿山和磷肥厂。本调查进行了矿区和磷肥生产车间氡气测量；磷矿石、磷矿渣系列产品及周边土壤的地表辐射测量和放射性核素分析；矿区生产用水及饮用水的总放射性分析，根据测量结果作出评价。     

某部营房氡浓度监测与评价

联合国原子辐射效应科学委员会 1993年报告指出 ,氡及其子体对公众所造成的年有效剂量约为天然辐射年有效剂量的 5 4% [1] 。所以 ,开展氡水平监测 ,有针对性地提出降氡措施 ,或对高氡营房进行治理 ,对于保障指战员健康有着非常重要的意义。为此在 1997～ 1999年秋冬季节 ,我们采用固体径迹探测器 ,对原国防科工委所属单位的营房氡浓度进行了全面的评价。一、材料和方法1 固体径迹探测器 :由ＣＲ 39探测片 (德国产 )、ＫｆＫ型氡扩散杯 (国产 )及聚丙烯纤维滤膜组成。主要仪器 :10 2 3型职业测氡仪 (美国ＳｕｎＮｕｃｌｅａｒ公司 ) ,曾在中…     

安徽省环境中氡浓度水平及对居民受照剂量的研究

本文报道了安徽省1719个调查点室内、外氡浓度,其浓度额频度服从对数正态分布,室内氡浓度均值为16.2Bq·m^-3,室外氡浓度均值为9.9Bq·m^-3,碳化砖住宅内氡浓度较高,均值为89.2Bq·m^-3．全省居民受室内,外氡及子件照射的人均年有效剂量当量为1.25mSv,集体年有效剂量当量为7.02×10⁴man·Sv·a^-1。     

浙江省天然本底辐射水平及其所致公众剂量

作者报道了浙江省天然本底辐射水平及其对公众所致的内、外照射剂量．结果表明：宇宙射线电离成分空气吸收剂量率人口加权平均值室外为３．０×１０（－８）Ｇｙ·ｈ（－１），室内为２．７×１０（－８）Ｇｙ·ｈ（－１），地表γ辐射空气吸收剂量率人口加权平均值室外为９．１×１０（－８）Ｇｙ·ｈ（－１）；室内为１４．９×１０（－８）Ｇｙ·ｈ（－１）；室内、室外空气中氡平均浓度分别为１７．２和１２．７Ｂｑ·ｍ（－３）；食品和水中天然放射性核素含量也分别进行了测定．由天然本底辐射所致公众人均年有效剂量总计为２．０ｍＳｖ，其中由宇宙射线，地表γ辐射，空气中氡、子体以及摄入天然放射性核素所致剂量分别为０．２４ｍＳｖ，０．７７ｍＳｖ，０．６７ｍＳｖ和０．３５ｍＳｖ，全省公众集体年有效剂量为８．５×１０４人·Ｓｖ．     

贵州省居民受天然放射性照射水平的研究与评价

贵州省居民受天然放射性照射水平的研究与评价李锁照陈煜友魏涛喻立新周瑞珍刘玉琴在生活环境中，人们始终受到电离辐射源的照射，其中天然电离辐射源的照射是主要的。我们根据环境贯穿辐射（γ辐射），空气中氡浓度，食品和饮用水中天然放射性核素的含量测定结果，估算了...     

吉林省天然本底辐射水平及其所致居民剂量

作者报道了吉林省夭然本底辐射水平及其对公众所致的内、外照射剂量。结果表明，宇宙射线电离成分空气吸收剂量率人口加权平均值为３．２×１０－８Ｇｙ·ｈ－１．地表γ辐射空气吸收剂量率人口加权平均值，室外为７．７×１０－８Ｇｙ·ｈ－１，室内为９．８×１０－８Ｇｙ·ｈ－１．室内、外空气中氡平均浓度分别为８．７Ｂｑ·ｍ－３和５．８Ｂｑ·ｍ－３。天然放射性核素Ｕ、Ｔｈ、２２６Ｒａ，４０Ｋ的平均含量分别是：食品中为３．７×１０－２Ｂｑ·ｋｇ－１，２．４×１０－２Ｂｑ·ｋｇ－１，１４．７×１０－２Ｂｑ·ｋｇ－１和８１．５Ｂｑ·ｋｇ－１；饮用水中为２．３×１０－２Ｂｑ·Ｌ－１，０．１×１０－２Ｂｑ·Ｌ－１，１．１×１０－２Ｂｑ·Ｌ－１和０．３Ｂｑ·Ｌ－１。由天然本底所致公众人均年有效剂量当量约为１．５ｍＳｖ．     

典型非铀矿山工人氡危险认知研究

目的 调查非铀矿山工人对氡所致健康危害的认知水平及影响因素。方法 采用当面填写调查表或询问方式调查了9个省区24个矿山的2836名矿工。结果 13.3%的矿工知晓氡,其中,29.0%的人知道氡的来源,8.5%的矿工对氡危害有一定认识,仅有1.8%的矿工对氡致健康危害有正确认知。在影响非铀矿山工人对氡致健康危害正确认知水平的因素中,受教育程度与氡认知水平正相关;正式职工对氡的认知水平优于临时雇用工人;性别、年龄、从事现工作的工龄等因素对氡认知水平没有明显影响;不同省区及矿山的氡认知水平不同。结论 我国非铀矿山矿工对氡危险认知水平较低,应进一步落实并规范《职业病防治法》规定的职业危害告知义务。     

山东省非铀矿山氡浓度测量及所致矿工剂量

目的 调查山东省典型非铀矿山井下²²²Rn浓度并估算矿工接受年有效剂量。方法 利用固体径迹探测器CR-39累积测量金矿、铁矿、煤矿井下²²⁰Rn、²²²Rn浓度,利用高纯锗γ谱仪分析矿石²²⁶Ra、²³²Th、⁴⁰K活度浓度。结果 山东非铀矿山井下²²⁰Rn浓度平均值由高到低依次为金矿、铁矿、煤矿、黏土矿,分别为1200、280、120和40 Bq/m³;煤矿、金矿、黏土矿和铁矿的²²⁶Ra、²³²Th、⁴⁰K活度浓度基本处于我国土壤天然放射性核素浓度范围内;²²²Rn及其子体所致井下矿工年有效剂量,金矿最高为7.7 mSv,铁矿次之,为1.7 mSv,煤矿和黏土矿均低于1 mSv。结论 金矿和铁矿应采取加大通风能力等措施降低井下氡浓度,井下矿工应该作为职业照射人员进行管理。     

大剂量维生素C联合环氧合酶2抑制剂治疗重症放射性直肠炎三例

放射性直肠炎是盆腔肿瘤放疗最常见的并发症,而传统药物治疗重症放射性直肠炎疗效有限,需探索新的治疗策略应用于临床。本研究报道3例重症放射性直肠炎患者,经大剂量维生素C联合环氧合酶-2(cyclooxygenase-2,COX-2)抑制剂治疗后,其腹泻、便血、里急后重、疼痛等症状明显改善,影像学复查直肠壁水肿较前明显好转,提示大剂量维生素C联合治疗重症放射性直肠炎具有较高的安全性和有效性。     

我国非铀矿山工作场所γ外照射剂量估算

目的 估算非铀矿山工作人员经由矿石样品外照射途径所致γ外照射年有效剂量。方法 现场采集非铀矿山矿工工作场所矿石样品,利用γ能谱仪测量矿石样品中放射性核素活度浓度,进而估算采矿工作场所矿工所受年有效剂量。结果 在全国7个省区13个矿区共采集、分析了32个矿石样品,其中有2种矿石活度浓度较高,所致矿工的年有效剂量超过1 mSv。结论 γ能谱测量分析方法可以较好地应用于非铀矿山矿石放射性核素分析,其结果可用来估算矿工所受的γ外照射剂量。     

非铀矿山氡致肺癌危险相关参数的调查

目的 调查非铀矿山从业人员职业氡暴露致肺癌危险估计所需参数。方法 对选自9省区13类24座矿山的2836名矿工,采用当面填写调查表或询问方式,调查了职业氡暴露致肺癌危险估计所需要的基本参数,包括平均工龄、开始暴露年龄、吸烟情况等。采用描述性统计方法进行分析。结果 非铀矿山在职职工年龄为17~72岁,平均年龄为(36.9±8.0)岁。非铀矿工受教育程度低,3%为文盲,58%接受了小学或初中教育,受过大专及以上教育的人仅7%。非铀矿工中75%为农民工,少数民族矿工的比例为16%。临时工开始职业氡暴露的年龄为(29.6±8.0)岁。到调查时,在矿山工作的工龄为(6.7±6.8)年,工龄中位数为4.1年,工龄≥5 年工人占46.7%。3.4%的在职职工在18岁以前开始矿山工作。有17.5%的工人报告每日工作时间大于8 h。被调查者中,58.0%(43.0%~83.0%)男性矿工为当前吸烟者,平均从20岁开始吸烟,吸烟量中位数为16支。 当前吸烟率与年龄有关,15~19岁矿工的吸烟率最高,达69.2%。煤矿工当前吸烟率为49.0%,非煤矿山工人为62.5%,两者差异具有统计学意义(χ²=59.1,P<0.01)。不同省区男性矿工吸烟率明显不同(χ²=1200,P<0.01)。煤矿工报告使用机械通风情况明显优于非煤矿山矿工(χ²=80.7,P<0.01)。结论 非铀矿山一线工人中75%为农民工。矿工约在30岁开始井下职业高氡暴露,但有3%的矿工在18岁以前开始从业,接近一半矿山工人工龄为5年及以上,男性矿工当前吸烟率无异于一般男性人群。     

Quantification of radiation induced DNA double-strand breaks in human fibroblasts by PFGE: testing the applicability of random breakage models

Purpose : To assess the applicability of methods of quantification of double-strand breaks (DSB) based on the random breakage paradigm, measuring yield and distribution of DSB induced by varying radiation quality. Material and methods : 240 kVp X-rays and 238 Pu α -particles were used to induce DSB in AG01522B primary human fibroblasts. DNA molecular weight distributions were resolved by means of three pulsed-field gel-electrophoresis (PFGE) protocols, which, when combined together, allowed separation and quantification of double-stranded fragments between 5.7 Mbp and 12 kbp. Several analytical methods quantified the DSB yields. Results : Data showed significant differences in the fragmentation patterns according to radiation quality. For both X-rays and α -particles, it was observed that the shape of the fragmentation profiles deviates from the prediction of a random breakage mechanism. This is in contrast to other studies where sparsely ionizing radiations appeared to distribute breaks uniformly throughout the genome. Deviations from random breakage were more evident after high linear energy transfer (LET) radiation, which showed an excess of breaks <1 Mbp and a deficit in the production of fragments >1 Mbp, a value that could be dose-dependent. Conclusions : Current methods of DNA fragmentation analysis after induction of DSB may lead to contradictory conclusions on both DSB yields and distributions. This study showed that the application of different DSB quantification methods, derived from random breakage or supported by its concepts, resulted in different radiation biological effectivenesses (RBE) for the induction of DSB, depending on how these methods were employed. To compare experimental results from different laboratories, care should be taken to provide as many details as possible about the application of methods of quantification of DNA damage. For all the methods used, total DSB yields resulted in RBE less than those for mutation induction or reproductive cell death, suggesting that total DSB yields only gave a limited indication of the severity of the inflicted damage. Production of correlated breaks on the chromatin loop structures by single particle-track traversals may explain the deviations observed between experimental data and the predictions of the random breakage paradigm.     

2020—2021年非铀矿工氡及其健康危害认知状况调查

目的了解我国非铀矿工氡及其健康危害的认知状况并分析影响因素,为放射卫生技术机构和用人单位开展氡的健康教育工作提供调研依据。方法采用整群随机抽样方法,在2020年6月—2021年12月从11个省份选择32座典型非铀矿山的男性矿工开展氡及其健康危害认知调查,并使用二元logistic回归模型分析非铀矿工氡知晓情况的影响因素。结果1184名被调查矿工的氡知晓率为19.17%,知晓氡的非铀矿工中有36.56%能准确说出氡的健康危害,18.06%能正确识别减少氡浓度的措施。单因素分析结果表明,非铀矿工氡知晓率在不同的受教育程度、劳动关系、岗位类别和地区间分布存在差异(χ^(2)=55.92、21.89、64.31、11.26,P<0.05)。logistic回归分析显示,本科及以上学历、正式工、岗位类别为行政管理人员和技术人员是氡知晓的影响因素(χ^(2)=12.81、6.58、5.66、21.44,P<0.05)。未发现非铀矿工氡知晓率与年龄、工龄、地区和吸烟有关(P>0.05)。结论我国非铀矿工氡及其健康危害认知水平较低,放射卫生技术机构和用人单位应采用媒体宣传、在岗培训、合同告知和工作场所宣传栏告知等措施加强非铀矿工氡相关知识的教育和培训,提高个人防护意识。     

Sensitivity of LR115 detector in diffusion chamber to Rn in the presence of Rn

Determination has been made of the sensitivity of LR115 type 2-track detectors (in units of m) to ²²²Rn, measured in the presence of ²²⁰Rn. Measurements have been made by means of a widely used diffusion chamber while Monte Carlo simulations have also been conducted. The experimentally derived sensitivities for ²²²Rn and ²²⁰Rn were found to be 0.470±0.022 and 0.486±0.042 m, respectively. For Monte Carlo simulations, the sensitivities to ²²²Rn gas were found to range from 0.618×10^–2 m (assuming that all ²¹⁸Po progeny decay before deposition onto the internal walls of the diffusion chamber) to 0.405×10^–2 m (assuming that all ²¹⁸Po progeny are deposited on the internal walls of the same containment vessel before decaying). The sensitivity to ²²⁰Rn gas of 0.465×10^–2 m found from Monte Carlo simulations agrees to within uncertainty with experimental findings. The experimentally derived sensitivity value for ²²²Rn indicates that 30% of the ²¹⁸Po progeny decay before deposition onto the internal walls of the diffusion chamber.     

Effects of Hypoxic Cell Radiosensitizers on the Activity of ATPases

Summary

The yield and repairability of DNA—protein cross-links have been compared after γ- or U.V.-irradiation of Chinese hamster V79-379 lung fibroblasts. Using a filter-binding assay, cross-linked DNA can be specifically isolated after doses between 10 and 100 Gy of γ-radiation and fluences between 20 and 300 J/m² of U.V.-radiation. After ionizing radiation, the majority of DNA cross-linked to protein is released with biphasic kinetics, requiring 1 h for removal of 50 per cent of the cross-linked DNA and 24 h for 90 per cent release. In these cells, U.V.-induced cross-linked DNA is not removed; on the contrary, the yield of apparent DNA—protein complexes increases during postirradiation incubation. Prior γ-irradiation, to initiate the associated repair system, does not stimulate release of U.V.-induced cross-linked DNA. Inhibition of protein synthesis by cycloheximide affects neither the removal of γ-ray-induced cross-linked DNA nor the increase in U.V.-induced cross-linked DNA. 3-Aminobenzamide, an inhibitor of poly(ADP-ribose) polymerase, slows the second phase of release after γ-irradiation as well as the increase in apparent cross-links after U.V.-irradiation. Thus, even though both types of DNA—protein cross-links can be detected by the same assay, their structures or other factors must be substantially different, since the repair system for one type does not recognize the other.     

Synergistic effect of Ebselen and gamma radiation on breast cancer cells

Purpose: To explore the synergistic effect of a seleno-organic compound Ebselen (Ebs) and/or γ-radiation to exert antitumor effects on human breast cancer (MCF-7) cell line in vitro.

Materials and methods: Ebs cytotoxicity at various concentrations (10, 25, 50 and 75 μg), cell proliferation and clonogenic assay of Ebs and/or γ-radiation (at 1, 3 and 6?Gy), expression of p-IκBα and NF-κB, inflammatory cytokines levels (TNF-α, IL-2, INF-γ, IL-10 and TGF-β), apoptotic factors (Caspase-3, Granzyme-B and TRAIL) and angiogenic factor (VEGF) were investigated.

Results: The results showed that the effective dosage of this combination was observed at 25 μg/ml of Ebs with γ-radiation at 6?Gy. Data displayed a significant reduction in NF-κB mRNA along with an elevation in granzyme-B mRNA and TRAIL mRNA expression. Furthermore, protein expression of caspase-3 was elevated, whereas p-IκBα and p-NF-κB(p65) protein expression was reduced significantly. Also, a significant decline in TNF-α, IL-2, INF-γ, TGF-β with a significant increase in IL-10 levels were revealed. Meanwhile, a significant decrease in VEGF level and proliferation capacity were observed.

Conclusions: We conclude that a combination of Ebs with radiotherapy has a major antitumor efficiency in inducing apoptosis and inhibiting cancer cell progression, due to the synergistic effect in regulating gene and protein expression, and in a modulating response of pro-and anti-inflammatory cytokines.