槲皮素干预实验性慢性肾衰的初步研究

目的 探讨槲皮素对动物实验性慢性肾衰的防治效果.方法 给实验大鼠饲以含腺嘌呤饲料2月造成慢性肾衰;干预组ig给予槲皮素（100mg·kg^-1·d^-1×42d）治疗.观察各组动物健康状况和死亡率;结束时精称存活大鼠体重、肾脏重并计算肾脏指数;烘干法测定肾组织含水量;常规方法行肾脏病理学检查;以贝克曼全自动生化分析仪测定血清肾功相关生化指标.结果 与肾衰对照组比较,干预组动物死亡率显著降低（20%vs84%）,存活鼠体重显著增大（240±22）g vs（109±14）g（P＜0.001）,肾脏指数和肾组织含水量均显著降低[（5.08±0.89）%vs（78.24±1.25）%和（12.63±2.94）%vs（79.29±0.90）%]（P＜0.001,P＜0.05）,肾脏病理学损伤改变明显较轻,血清肾功相关生化指标（BUN、CREA、URIC和GLU）改变显著减轻[（20.9±5.7）、（82.8±51.5）、（155.9±24.3）、（11.79±1.54）vs（78.7±14.0）、（246.7±55.9）、（108.7±31.5）、（8.14±0.74）]（P＜0.001）.结论 槲皮素对大鼠实验性慢性肾衰具有显著防治作用.     

基于DCE-MRI Ktrans纹理分析评价四氧嘧啶诱导兔糖尿病早期骨骼肌变化

【摘要】目的：采用基于动态对比增强磁共振成像（DCE-MRI）容量转移常数（Ktrans）纹理分析评价四氧嘧啶诱导兔糖尿病早期骨骼肌变化。方法：18只雄性日本大耳白兔随机分为糖尿病组（n=10）和对照组（n=8）。四氧嘧啶造模成功后各时间点（0、4、8、12、16周）对所有兔腰部多裂肌行轴位FSE-T1WI、FSE-T2WI及DCE-MRI检查。通过拟合药代动力学模型获得多裂肌DCE-MRI定量参数Ktrans，并于Ktrans图提取灰度共生矩阵（GLCM）参数能量、熵、自相关、逆差矩及对比度。16周处死所有兔，取腰部多裂肌行HE染色计算肌纤维横截面积（CSA），行CD31免疫组化染色计算微血管密度（MVD）及毛细血管数/肌纤维数（C/F）。采用独立样本t检验或Mann-Whitney U检验比较同一时间点糖尿病组、对照组多裂肌Ktrans值及GLCM参数的差异。对不同时间点Ktrans值及GLCM参数差异比较采用重复测量的方差分析或Friedman检验。两组间多裂肌CSA、MVD及C/F值差异比较采用独立样本t检验。将Ktrans与MVD及C/F值行Pearson相关分析。结果：不同时间点Ktrans、熵、逆差矩、对比度在糖尿病组差异具有统计学意义（F值分别为33.563、16.790、19.128、3.577，P均＜0.05）。不同时间点糖尿病组自相关差异无统计学意义（F=3.024，P=0.068）。糖尿病组Ktrans及熵第8、12、16周较第0、4周升高，逆差矩第8、12、16周较第0、4周减低（P均＜0.05），Ktrans在第8周以后出现降低趋势。糖尿病组对比度第8周较第0周升高（P＜0.001），能量第8周较第4周减低（P=0.047）。Ktrans、熵、自相关、逆差矩、对比度及能量在对照组差异均无统计学意义（P均＞0.05）。与对照组相比，糖尿病组第8、12及16周GLCM参数熵升高，逆差矩减低（P均＜0.05）；糖尿病组第8周能量减低（Z=-2.310，P＜0.05），对比度增高（t=2.374，P＜0.05）。自相关在两组间差异均无统计学意义（P均＞0.05）。第16周糖尿病组多裂肌CSA、C/F值低于对照组（t值分别为-11.081、-12.812，P均＜0.001），MVD值高于对照组（t=7.672，P＜0.001）。Pearson相关分析结果显示Ktrans与C/F呈负相关（r=-0.809，P＜0.05），而与MVD呈正相关（r=0.681，P＜0.05）。结论：DCE-MRI定量参数Ktrans可用于评估糖尿病骨骼肌微血管渗透性改变，基于Ktrans图的GLCM参数可识别糖尿病早期骨骼肌微结构变化。      

肺结核合并肺部感染患者的病原菌分布特征及血清炎症因子水平与其严重程度的相关性分析

目的 研究肺结核合并肺部感染患者的病原菌分布特征及血清肿瘤坏死因子 (tumor necrosis factor-α,TNF-α)、降钙素原(procalcitonin,PCT)、γ干扰素(interferon gamma,IFN-γ)水平与肺感染严重程度的相关性。方法 本研究主要以2019年1月至2021年12月收治的120例肺结核合并肺部感染患者作为观察组,另选取同期单纯性肺部感染患者120例作为对照组,分析观察组患者病原菌的感染情况、两组不同严重程度患者的TNF-α、PCT、IFN-γ水平之间的差异,研究肺炎的严重程度与TNF-α、PCT、IFN-γ水平的相关性。结果 肺结核合并肺部感染患者中,真菌感染患者13例,革兰氏阳性菌感染36例,革兰氏阴性菌感染71例,其中在革兰氏阴性菌感染中主要以肺炎克雷伯菌为主;在对照组中,主要以革兰氏阴性菌为主,其中以铜绿假单胞菌感染为主。观察组患者的TNF-α（t=10.254,P<0.001）、PCT（t=13.286,P<0.001）、IFN-γ（t=34.407,P<0.001）水平显著高于对照组;不同严重程度患者的TNF-α（F=26.761,P<0.001）、PCT（F=7.288,P<0.001）、IFN-γ（F=37.925,P<0.001）水平之间的差异存在统计学意义,经过两两比较,不同严重程度患者的TNF-α、PCT、IFN-γ水平从高到低依次为高风险组、中风险组以及低风险组;通过相关性分析,患者的疾病严重程度与TNF-α、PCT、IFN-γ水平呈现正相关。结论 肺结核合并肺部感染患者的病原菌分布主要以革兰氏阴性菌为主,血清TNF-α、PCT、IFN-γ水平与肺感染严重程度呈现显著的相关性。     

外周血干细胞和骨髓基质细胞联合输注对急性放射病造血重建作用的实验研究

目的：观察外周血干细胞联合骨髓基质细胞输注对急性放射病造血功能恢复的影响。方法：8．5Gyγ射线照射的BALB／c小鼠，分别输入红细胞（对照组），动员的外周血干细胞（PBSCT组），外周血干细胞联合扩增的骨髓基质细胞（实验组），观察受体鼠4周的生存率，骨髓有核细胞（BMNC），粒细胞巨噬细胞集落形成单位（CFU－GM），成纤维细胞集落形成单位（CFU－F），外周血白细胞计数（WBC）等指标。结果：实验组的生存率，BMNC、GFU－GM，CFU－F较对照组和PBSCT组显著升高，P＜0．05，WBC的最低值较其他两组高（P＜0．01），WBC恢复较PBSCT组愉（P＜0．01），结论：外周血干细胞联合骨髓基质细胞 输注有促进急性放射病造血重建的作用，其作用优于单纯的外周血干细胞输注（移植）。     

不同功能状态滋养层对人胚胎生殖嵴干细胞生长作用的实验研究

目的筛选并建立高效胚胎干细胞滋养层体外培养的最佳条件,利于人胚胎生殖嵴原始生殖细胞（PGC）的增殖。方法分离培养孕14.5 d（E14.5 d）和新生0 d（P0）昆明小鼠原代胚胎成纤维细胞（MEF）并传代制备滋养层,以60Coγ射线照射后继续培养并接种人PGC。采用活细胞拒染法、免疫细胞化学染色,对比观察滋养层的生长活性和照射后分泌功能;采用碱性磷酸酶（AKP）染色技术鉴定人PGCs的生长状态。结果 （1）E14.5 d和P0来源的第3～5代MEF生长旺盛。P0来源第6代与E14.5 d来源同代MEF相比深染变形细胞增达32%,经60Coγ照射后衰老细胞明显增多（P〈0.05）。（2）E14.5 d来源第3～6代和P0来源第3～4代MEF经60Coγ照射后培养5 d时,Ⅰ型胶原蛋白免疫阳性细胞数目较多,染色较深;但P0来源第5代其阳性细胞数目明显减少,染色变浅。（3）人PGCs接种于E14.5 d第3代制备的滋养层3～4 d后见典型的ESC小克隆团,细胞呈圆形;AKP染色呈深蓝色团;而接种于P0来源第6代MEF制备的滋养层5～6 d,可见ESC克隆松散、变大,周围边界不清,细胞紊乱。结论以60Coγ射线照射小鼠E14.5 d来源第3～6代MEF是制备滋养层的最佳来源,可维持人PGCs增殖。     

电离辐射抑制海马区神经发生与放射性脑损伤认知损害的关系

目的 研究放疗后海马区神经发生与小鼠放射性脑损伤认知损害的关系.方法 10 d龄C57BL/6J小鼠24只给予10 Gy 6MV X射线全脑照射,Morris水迷宫实验检测放射性脑损伤模型的建立.在照射后不同时间点(0.5、3、6、12、24、48、72 h,1、2、4、8、16、24周),取脑组织标本进行HE染色,观察海马区神经细胞的病理变化.免疫组织化学染色双皮质蛋白(DCX)、增殖细胞核抗原(PCNA)标记海马区神经发生水平,ED1标记小胶质细胞激活情况,TUNEL标记海马区神经细胞凋亡情况.采用Real-time PCR法检测脑组织TNF-α、IL-1β表达水平的变化;酶联免疫吸附法(ELISA)检测照射后不同时间点血浆TNF-α水平的变化.结果 照射后急性期表现为间质水肿,炎性细胞浸润,海马区齿状回神经细胞逐渐出现变性、坏死、凋亡,慢性期间质水肿消退,炎性细胞减少,海马齿状回出现细胞再生呈极性分布.受照后各时间点,DCX阳性细胞和PCNA阳性细胞较对照组均有不同程度减少(F =4.9 ～12.5,5.2～15.7,P＜0.05),受照后ED1阳性细胞较对照组增多(F=20.8,P＜0.05).TUNEL标记凋亡神经元在放疗后6h可见,于48 h达到峰值(F=15.1,P＜0.05);照射后0.5h,γ-H2AX焦点形成达到高峰(F=18.4,P＜0.05),后逐渐减少.照射后脑组织TNF-α和IL-1β表达较对照组均有所增加(t=16.3、12.7,P＜0.05);血浆TNF-α照射后3h开始升高,至1周达到峰值(F=10.5,P＜0.05),随后逐渐降低.Morris水迷宫实验照射组和对照组相比,照后1、2、3d两者差异无统计学意义,但随着时间的延长,4、5、6d照射组躲避潜伏期较对照组延长(F=7.01、8.17、4.22,P＜0.05).结论 10 Gy全脑照射后,建立放射性脑损伤模型,发现海马区神经发生受到抑制和小胶质细胞激活可能是小鼠放射性脑损伤认知损害产生的原因之一.     

不同剂量137Cs γ射线照射对小鼠造血系统的影响

目的 探讨不同剂量γ射线照射对不同品系小鼠造血功能的影响。 方法 用137Cs γ射线分别对IRM-2、ICR、615品系小鼠进行一次性全身4.0 Gy γ射线照射,在照后不同时间检测小鼠外周血白细胞、骨髓有核细胞（BMNC）的变化。对IRM-2小鼠、C57BL/6小鼠进行6.0 Gy γ射线照射,照后第45日,检测小鼠外周血象的变化。 结果 IRM-2、ICR、615品系小鼠经4.0 Gy照射后第2日,白细胞和BMNC数量降至最低值。第9日,IRM-2小鼠的BMNC计数与ICR、615小鼠相比,差异有统计学意义（t=3.725,P＜0.01;t＝8.487,P＜0.001）。第12日,IRM-2小鼠白细胞计数与ICR、615小鼠相比,差异有统计学意义（t=4.811和4.302,P均＜0.001）。第21日,IRM-2、ICR、615小鼠白细胞计数分别恢复到正常值的52.0%、60.7%、50.8%;BMNC计数分别恢复到正常值的90.8%、82.1%、75.4%。IRM-2、C57BL/6小鼠经6.0 Gy γ射线照射后第45日,IRM-2小鼠外周血白细胞、红细胞、血红蛋白（Hgb）、红细胞压积（Hct）计数均明显高于C57BL/6小鼠（t=5.629、7.788、4.929和6.064,P均 < 0.001）;IRM-2小鼠白细胞、红细胞、Hgb、Hct数量分别恢复至正常值的75.00%、98.95%、98.78%、97.55%;C57BL/6小鼠白细胞、红细胞、Hgb、Hct数量分别恢复至正常值的40.60%、93.88%、93.31%、93.84%。 结论 IRM-2、ICR、615、C57BL/6小鼠受照后造血功能的恢复趋势相同,但IRM-2小鼠在辐射损伤后其造血功能的恢复较快于ICR、615、C57BL/6小鼠。     

TH1/TH2在慢性乙型肝炎发病机制中的作用

目的：研究Th1/Th2变化在慢性乙型肝炎发病机制中的作用。方法：采用双抗体酶联分析法检测了20例正常人，30例慢性乙型肝炎患者血清中的IFN－γ，IL－2，IL－4和IL－6的水平。结果：慢性乙型肝炎组Th2类细胞因子（IL－4，IL－6）水平明显高于正常对照组（P＜0．05）,Th1类细胞因子IL－2水平较正常组也增高（P＜0．05），IFN－γ水平轻度增加，但无统计学差异（P＞0．05），结论:Th2类细胞因子水平增高以及由此引起的Th1/Th2比值下降可能与慢性乙型肝炎的病程持续有关。     

PET预测结肠癌转移潜能的实验研究

目的 评价PET在预测结肠癌转移特性中的作用。方法体外培养人结肠癌SW480、SW620细胞并分别种植裸鼠,形成移植瘤,观察肿瘤生长、转移情况以及生存期。分别于体内、体外检测肿瘤细胞对18F,脱氧葡萄糖（FDG）、18F-脱氧胸腺嘧啶核苷（FLT）的摄取。在体外分别于30,60,90和120min测定肿瘤细胞摄取18F—FDG与18F—FLT的放射性。经鼠尾静脉注射18F—FDG、18F—FLT,60min后行动物PET显像,利用感兴趣区（ROI）计算肿瘤／正常组织放射性（TINT）比值。应用免疫细胞化学染色与Westernblot法检测细胞以及肿瘤组织热休克蛋白27（HSP27）、整合素B3（Integrinβ3）、血管内皮生长因子受体2（VEGFR2）、核增殖抗原（Ki67）蛋白表达。应用独立样本t检验、Fisher精确检验以及直线回归分析研究体内外放射性摄取的差异以及放射性摄取与肿瘤标志物表达之间的关系。结果SW480移植瘤较SW620肿瘤成瘤早、生长快、生存期短、肝肺转移率高。体外摄取实验示,18F—FDG在SW480与SW620细胞中的摄取60min时分别达到（1．76±0．87）％和（1．14±0．38）％（t=-2．507,P=0．021）;18F-FLT分别达到（5．21±1．60）％和（2．90±1．82）％（t=3．497,P=0．002）。SW480较SW620细胞摄取“F—FDG、18F—FLT高,18F—FLT在细胞内的摄取高于18F—FDG。动物PET显像示,18F-FDG在SW480与SW620肿瘤中的T／NT比值分别为2．69±0．98,3．09±1．26（t=0．657,P=0．524）;18F-FLT T／NT比值分别为3．65±0．51,2．22±0．42（t=6．491,P〈0．001）;18F—FLT摄取与肿瘤组织内HSP27表达（r=0．924,P=0．004）、Integrinβ3表达（r=0．813,P=0．025）呈明显正相关。而18F-FDG的摄取与荷瘤鼠的生存期呈明显负相关（r=-0．500,P=0．017）。结论18F—FDG、18F—FLTPET在肿瘤内的摄取可反映结肠癌不同的生物学行为,18F—FLT在结肠癌内的高摄取可预测结肠癌具有高转移潜能。     

补体激活在流感病毒介导的肺部炎性损伤中的作用及眼镜蛇毒因子干预的实验研究

目的：揭示流感病毒介导的小鼠肺部炎性损伤机制,为研发治疗病毒性肺炎的有效药物提供理论和技术依据。方法建立流感PR8感染小鼠动物模型,利用实时荧光定量PCR、ELISA、病理切片等方法检测小鼠肺部炎症因子、补体分子及病理变化;按照50μg／（kg·24 h）的剂量腹腔注射眼镜蛇毒因子（CVF）,监测小鼠体质量、存活率、炎症因子等变化。结果与对照组相比,PR8流感模型组小鼠肺组织中补体调节分子Crry、CD59表达显著下降（P＜0．01）,补体分子C9和补体成分受体C3aR、C5aR表达显著升高（P＜0．01）,血清中促炎因子TNF-α、IL-6、IFN-γ高表达,抗炎因子IL-2低表达（P＜0．05）;经CVF药物干预后,小鼠体质量下降缓慢,存活率升高,肺指数降低（P＜0．05）,抗炎因子IL-2表达明显升高（P＜0．05）,促炎因子IL-6、TNF-α、INF-γ表达显著下降。结论补体激活参与了流感病毒介导的肺部炎性损伤;通过CVF干预,抑制了补体激活,可提高感染小鼠存活率,降低肺指数,延缓病程。     

Radioactivity and radon emanation fraction of the granites sampled at Misasa and Badgastein.

The chemical composition was analyzed and the radioactivity, radon exhalation rate and emanation fraction were measured to investigate the characteristics of the granites sampled at Misasa and Badgastein, world famous for radon therapy. The Misasa granite was probably composed of quartz, albite and microcline. The Badgastein granite was probably composed of quartz and muscovite. The radon exhalation rates and emanation fractions of the Misasa granite were much higher than those of the Badgastein granite, regardless of the (226)Ra activity concentrations.     

Differences of natural radioactivity and radon emanation fraction among constituent minerals of rock or soil

We examined differences in the radioactive characteristics among the main minerals forming granite materials. Using a non-toxic high-density agent, minerals were separated from rock (granite–gneiss) and soil (weathered granite) samples. The natural radioactivity (²³⁸U and ²²⁶Ra) and radon emanation fraction of the minerals were then studied by gamma-ray spectrometry. The radon emanation fractions (27–43%) of the minerals from the soil were much higher than those (0.6–4.6%) of the rock minerals. Additionally, the emanation fractions differed greatly among the minerals separated from both the bulk rock and soil. These results were discussed in terms of the differences of surface area and radium distribution in the mineral grains. It was noticeable that a higher emanation fraction than expected for quartz was commonly observed in the rock and soil samples. We then estimated the contribution of each constituent mineral to the total radon exhalation from the bulk samples. The result depended not only on the radon emanation fraction, but also on the ²²⁶Ra activity and the mineral content. Furthermore, using the obtained data, we also discussed the effect of grain size on radon emanation and why this has been reported to vary markedly in previous studies.     

Application of the can technique and radon gas analyzer for radon exhalation measurements

A passive “can technique” and an active radon gas analyzer with an emanation container were applied for radon exhalation rate measurements from different construction materials, viz. five marble seven ceramic and 100 granite tiles used in Saudi Arabia. The marble and ceramic tiles did not show detectable radon exhalation using the active radon gas analyzer system. However the granite tiles showed relatively high radon exhalations, indicating a relatively high uranium content. A comparison of the radon exhalation rates measured by the two techniques showed a linear correlation coefficient of 0.57. The radon exhalation rates from the granites varied from 0.02 to 6.58 Bq m⁻² h⁻¹ with an average of 1.35±1.40 Bq m⁻² h⁻¹. The geometric mean and the geometric standard deviation of the frequency distribution were found to be 0.80 and 3.1, respectively. The track density found on the nuclear track detectors in the can technique exposed to the granites, having high exhalation rates, varied linearly with exposure time with a linear correlation coefficient of 0.99. This experimental finding agrees with the theoretical prediction. The can technique showed sensitivity to low radon exhalation rates from ceramic, marble and some granite over a period of 2 months, which were not detectable by the active radon gas analyzer system. The reproducibility of data with both measuring techniques was found to be within a 7% deviation.     

Measurement of radioactivity and radon exhalation rate in different kinds of marbles and granites

Geological materials usually contaminated with naturally occurring radioactive materials (NORM) have become a focus of great attention. These NORM under certain conditions can reach hazardous contamination levels. Some contamination levels may be sufficiently severe that precautions must be taken.

The present study deals with 60 geological samples (marble and granite) from both Egyptian and foreign locations. The studied samples were analyzed and the concentrations in Bq/kg dry weight of radioisotopes were determined by gamma-ray spectrometry using hyper-pure germanium (HPGe) detector in Bq/kg dry weight. The absorbed dose rate due to the natural radioactivity in the samples under investigation ranged from 2.45±0.07 to 64.44±1.93 nGy/h for marble and from 41.55±1.25 to 111.94±3.36 nGy/h for granite. The radium equivalent activity varied from 5.46±0.16 to 150.52±4.52 Bq/kg for marble samples and from 229.52±6.89 to 92.16±2.76 Bq/kg for granite. The representative external hazard index values for the corresponding samples are also estimated and given.

The radon exhalation rates for marble and granite samples were also calculated by using solid state nuclear track detector (CR-39). The value of radium exhalation rate varied from 8.0±2.39 to 30.20±5.06 Bq/m²/d for marble and 6.89±1.72 to 25.79±4.38 Bq/m²/d for granite and the effective radium content was found to vary from 1.700±0.51 to 6.42±1.08 Bq/kg for marble and 1.29±0.32 to 5.63±0.96 Bq/kg for granite. The values of the radon exhalation rate and effective radium content are found to correspond with the values of uranium concentration measured by the HPGe detector in the corresponding sample.     

Effect of lower grain sized particles on natural radiation level of the Ponnaiyar river sediments

River sediment depositions on the bottom of rivers most frequently consist of sand and gravel particles with different grain sizes, which make them particularly valuable for the building construction. Knowledge of radioactivity present in building material enables one to assess any possible radiological hazard to mankind by the use of such materials. The natural radionuclide (²³⁸U, ²³²Th and ⁴⁰K) contents have been analyzed for the sediment samples of Ponnaiyar River with an aim of evaluating the radiation hazard nature. To know the radiological characteristics of the sediment, dose rate is calculated and are compared with recommended values. Mineral characteristics of the sediments have been analyzed through FTIR and XRD techniques. Extinction coefficient and Crystallinity index is calculated to know the relative distribution of major minerals and crystalline nature of quartz, respectively. Multivariate statistical analyses were carried to find the relationship between the radioactivity characteristics and minerals, the results obtained in the study suggest that the level of natural radioactivity of the present sediments mainly depends upon the amount of kaolinite (clay). Mineral characterization of various grain sized sediments show clay and magnetic minerals are rich in lower grain sized (≤120 μm) samples. The level of radioactivity has also been measured for >120 μm sediments and results show that both activity concentrations and dose rate are considerably lowered when compared with the respective values of the bulk samples. The removal of ≤120 μm particles from the sediments of the river make it safer to use these materials for building construction.     

珠海室内氡水平及分布特征

目的 通过对珠海市3个典型区域进行调查,探讨不同地质背景区域室内氡浓度的水平和分布.方法 按照地表岩性不同,分为珠海花岗岩、斗门花岗岩和斗门第四纪3个测区,使用活性炭盒累积法进行室内氡浓度测量.在部分测点同时使用活性炭盒累积法和固体径迹法进行室内氡浓度测量.结果 对80间房屋的活性碳盒累积法测量结果显示,珠海平均室内氡浓度为(66.0±49.8) Bq/m3,最大室内氡浓度为1078.5 Bq/m3.测区内23个测点短期活性炭盒累积法的测量结果为(69.5±37.7) Bq/m3,长期固体径迹法的测量结果为(88.8±49.1) Bq/m3.不同地表岩性区域室内氡浓度分别为:珠海花岗岩测区为(73.6±61.0)Bq/m3、斗门花岗岩测区为(87.5±58.3) Bq/m3、斗门第四纪测区为(48.6±22.6) Bq/m3.结论 地表岩性对区域室内氡浓度水平具有明显影响,珠海花岗岩和斗门花岗岩测区室内氡浓度明显高于斗门第四纪测区.建议结合地质背景研究区域室内氡浓度水平与分布特征.     

Measurement of natural radioactivity in building materials of Namakkal, Tamil Nadu, India using gamma-ray spectrometry

The natural level of radioactivity in building materials is one of the major causes of external exposure to γ-rays. The primordial radionuclides in building materials are one of the sources of radiation hazard in dwellings made of these materials. By the determination of the radioactivity level in building materials, the indoor radiological hazard to human health can be assessed. This is an important precautionary measure whenever the dose rate is found to be above the recommended limits. The aim of this work was to measure the specific activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K in commonly used building materials from Namakkal, Tamil Nadu, India, using gamma-ray spectrometer. The radiation hazard due to the total natural radioactivity in the studied building materials was estimated by different approaches. The concentrations of the natural radionuclides and the radium equivalent activity in studied samples were compared with the corresponding results of different countries. From the analysis, it is found that these materials may be safely used as construction materials and do not pose significant radiation hazards.     

Assessment of radon-222 concentrations in buildings, building materials, water and soil in Jordan.

Monitoring of radon gas ((222)Rn) in Jordan was started in the early 1990s. Since then our radon group at Yarmouk University and others have carried out tens of studies that include measurements of indoor radon, radon in water, radon in soil and radon emanating from building materials. All major cities of Jordan had been surveyed, from the northern city of Irbid down to the southern port city of Aqaba. Most of these studies were carried out by using time-integrated passive radon dosimeters containing CR-39 solid-state nuclear track detectors. In addition to that, an active radon monitor was used to study the seasonal variation of (222)Rn in Al-Ruseifa that lies near abandoned phosphate mines and in Amman area. During such a study passive dosimeters were also used. The average radon concentrations in dwellings in Jordanian cities ranged from about 20 to 386 Bq/m(3) with the highest readings exhibited during the winter season around the town of Al-Ruseifa.     

新建居住建筑物室内氡浓度与换气率关系研究

目的 初步探索新建居住建筑物室内氡浓度与换气率关系。方法 选择广州和合肥两处新建毛坯房屋测量室内氡浓度与换气率,采用测氡仪连续测量室内氡浓度,采用示踪气体稀释法测室内换气率。结果 广州房屋封闭条件连续测量48 h,两间卧室内氡浓度均值分别为106和115 Bq/m³,范围分别为17~181 Bq/m³和6~224 Bq/m³,换气率分别为0.16和0.21次/h。合肥房屋封闭条件下两次连续测量48 h,同一卧室内氡浓度均值分别为148和186 Bq/m³,范围分别为8~224和14~290 Bq/m³,换气率分别为0.14和0.12次/h。室内氡浓度随室内换气率的增加呈指数下降趋势。结论 我国新建节能设计居住建筑物换气率低导致室内氡污染的问题应该引起重视。     

建筑节能设计对严寒和寒冷地区居室氡浓度和换气率的影响

目的 初步分析严寒和寒冷地区建筑节能设计对居室氡浓度的影响。方法 选择哈尔滨、佳木斯、沈阳、西宁、银川共5个城市的25户住宅,密闭门窗24 h测量氡浓度及其子体和换气率。采用RAD7测氡仪连续测量室内氡浓度,BWLM-PLUS工作水平氡子体测量仪连续测量氡子体,采用示踪气体稀释法测室内换气率。结果 25户住宅密闭门窗24 h,室内氡浓度均值为122 Bq/m³,范围为33~255 Bq/m³,室内氡浓度24 h均值有36%超过了150 Bq/m³。室内氡子体平衡因子均值为0.47,范围为0.20~0.72,换气率的均值为0.19次/h,范围为0.05~0.39次/h。室内氡浓度随房屋建筑年代的变化呈现增高的趋势,而换气率随房屋建筑年代的变化呈现降低趋势。结论 严格的建筑节能设计是近年我国居室氡浓度增加的重要影响因素,节能居住建筑的室内氡污染问题值得关注。