Effects of dust controls on respirable coal mine dust composition and particle sizes:case studies on auxiliary scrubbers and canopy air curtain

Control of dust in underground coal mines is critical for mitigating both safety and health hazards.For decades,the National Institute of Occupational Safety and Health(NIOSH)has led research to evaluate the effectiveness of various dust control technologies in coal mines.Recent studies have included the evaluation of auxiliary scrubbers to reduce respirable dust downstream of active mining and the use of canopy air curtains(CACs)to reduce respirable dust in key operator positions.While detailed dust characterization was not a focus of such studies,this is a growing area of interest.Using preserved filter samples from three previous NIOSH studies,the current work aims to explore the effect of two different scrubbers(one wet and one dry)and a roof bolter CAC on respirable dust composition and particle size distribution.For this,the preserved filter samples were analyzed by thermogravimetric analysis and/or scanning electron microscopy with energy dispersive X-ray.Results indicate that dust composition was not appreciably affected by either scrubber or the CAC.However,the wet scrubber and CAC appeared to decrease the overall particle size distribution.Such an effect of the dry scrubber was not consistently observed,but this is probably related to the particular sampling location downstream of the scrubber which allowed for significant mixing of the scrubber exhaust and other return air.Aside from the insights gained with respect to the three specific dust control case studies revisited here,this work demonstrates the value of preserved dust samples for follow-up investigation more broadly.

Dual specimens increase the diagnostic accuracy and reduce the reaction duration of rapid urease test

AIM:To evaluate the influence of multiple samplings during esophagogastr oduodenoscopy(EGD) on the accuracy of the rapid urease test,and the validity of newly developed rapid urease tests,HelicotecUT plus test and HelicotecUT test,CLO test and ProntoDry test.METHODS:A total of 355 patients undergoing EGD for dyspepsia were included.Their Helicobacter pylori(H.pylori) treatment status was either nave or eradicated.Six biopsy specimens from antrum and gastric body,respectively,were obtained during EGD.Single antral specimens and dual(antrum+body) specimens were compared.Infection status of H.pylori was evaluated by three different tests:culture,histology,and four different commercially available rapid urease tests(RUTs)-including the newly developed HelicotecUT plus test and HelicotecUT test,and established CLO test and ProntoDry test.H.pylori status was defined as positive when the culture was positive or if there were concordant positive results among histology,CLO test and ProntoDry test.RESULTS:When dual specimens were applied,sensitivity was enhanced and RUT reaction time was signif icantly reduced,regardless of their treatment status.Thirty minutes were enough to achieve an agreeable positive rate in all the RUTs.Both newly developed RUTs showed comparable sensitivity,specif icity and accuracy to the established RUTs,regardless of patient treatment status,RUT reaction duration,and EGD biopsy sites.CONCLUSION:Combination of antrum and body biopsy specimens greatly enhances the sensitivity of rapid urease test and reduces the reaction duration to 30 min.

Relationship between genetic polymorphisms of alcohol and aldehyde dehydrogenases and esophageal squamous cell carcinoma risk in males

AIM： To investigate the association between the genetic polymorphisms of ADH2 and ALDH2, lifetime alcohol consumption and esophageal cancer risk in the Taiwan Residents men. METHODS： Between August 2000 and June 2003, 134 pathologically-proven esophageal squamous cell carcinoma male patients and 237 male controls were recruited from Kaohsiung Medical University Hospital and Kaohsiung Veterans General Hospital in southern Taiwan. ADH2 and ALDH2 polymorphisms were genotyped using PCR-RFLP. RESULTS： Compared to those with ADH2＊2/＊2, individuals with ADH2＊1/＊2 and ADH2＊1/＊1 had 2.28- and 7.14-fold, respectively, increased risk of developing esophageal cancer （95%CI = 1.11-4.68 and 2.76-18.46） after adjusting for alcohol consumption and other covariates. The significant increased risk was also noted among subjects with ALDH2＊1/＊2 （adjusted OR （AOR） = 5.25, 95%CI = 2.47-11.19）, when compared to those with ALDH2＊1/＊1. The increased risk of esophageal cancer was made greater, when subjects carried both ADH2＊1/＊1 and ALDH2＊1/＊2, compared to those with ADH2＊1/＊2 or ADH2＊2/＊2 and ALDH2＊1/＊1 （AOR = 36.79,95%a = 9.36-144.65）. Furthhermore, we found a multipticative effect of lifetime alcoholic consumption and genotypes （ADH2 and ALDH2） on esophageal cancer risk. CONCLUSION： Our findings suggest that polymorphisms of ADH2 and ALDH2 can modify the influence of alcoholic consumption on esophageal cancer risk.

Statin use and the risk of colorectal cancer: A population-based case-control study

AIM: To investigate whether the use of statins is associated with colorectal cancer risk. METHODS: We conducted a population-based case-control study in Taiwan. Data were retrospectively collected from the Taiwan National Health Insurance Research Database. Cases consisted of all patients who were aged 50 years and older and had a first-time diagnosis of colorectal cancer between the period 2005 and 2008. The controls were matched to cases by age, sex, and index date. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multiple logistic regression. RESULTS: We examined 1156 colorectal cancer cases and 4624 controls. The unadjusted ORs for any statin prescription was 1.10 (95% CI = 0.94-1.30) and the adjusted OR was 1.09 (95% CI = 0.91-1.30). When statin use was categorized by cumulative dose, the adjusted ORs were 0.99 (95% CI = 0.78-1.27) for the group with cumulative statin use below 105 defined daily doses (DDDs); 1.07 (95% CI = 0.78-1.49) for the group with cumulative statin use between 106 and 298.66 DDDs; and 1.30 (95% CI = 0.96-1.75) for the group with cumulative statin use of 298.66 DDDs or more compared with nonusers. CONCLUSION: This study does not provide support for a protective effect of statins against colorectal cancer.

Analysis of roof and pillar failure associated with weak floor at a limestone mine

A limestone mine in Ohio has had instability problems that have led to massive roof falls extending to the surface. This study focuses on the role that weak, moisture-sensitive floor has in the instability issues.Previous NIOSH research related to this subject did not include analysis for weak floor or weak bands and recommended that when such issues arise they should be investigated further using a more advanced analysis. Therefore, to further investigate the observed instability occurring on a large scale at the Ohio mine, FLAC3 D numerical models were employed to demonstrate the effect that a weak floor has on roof and pillar stability. This case study will provide important information to limestone mine operators regarding the impact of weak floor causing the potential for roof collapse, pillar failure, and subsequent subsidence of the ground surface.

Full-Scale Measurement and Numerical Analysis of Liquefied Petroleum Gas Water Heaters with Ventilation Factors in Balcony

This study carried out full-scale gas water heater combustion experiments and adopted FDS （fire dynamics simulator） to simulate three scenarios--different balcony environments when using water heater, such as airtight balcony, indoor door with openings and force ventilation to compare with full-scale combustion experiments. According to FDS simulation results, 02, CO and CO2 simulation concentration value correspond with full-scale experimental results. When the indoor O2 concentration was lower than 15%, which causes incomplete combustion, the CO concentration would rise rapidly and even reached above 1,500 ppm, causing death in short time. In addition, when the force ventilation model supplied the water heater with enough air to bum, the indoor CO concentration will keep low and harmless to humans. The study also adopted diverse variables, such as the opening area of window, outdoor wind speed and water heater types, to analyze deeply user＇s safety regarding gas water heater. In a result, while balcony area is larger than 14 mE, the volume of water heater is below 16 L （33.1 kW）, and the indoor window, connecting balcony with room, is closed, if the opening on the outdoor window of the balcony is larger than 0.2 mE, this can ensure the personal security of the indoor space.

Association between Helicobacter pylori seropositivity and digestive tract cancers

AIM： To explore the role of Helicobacter pylori （Hpylori） infection on the risk of digestive tract cancers. METHODS： In total, 199 oral squamous-cell carcinoma （SCC）, 317 esophagea! SCC, 196 gastric cardia and non-cardia adenocarcinoma and 240 colon adenocarcinoma patients were recruited for serum tests of Hpylori infection. Two hospital- and one community-based control groups were used for the comparisons. Hpylori seropositivity was determined by an enzyme linked immunosorbent assay method against Hpylori IgG. RESULTS： Presence of H pylori infection was significantly inversely associated with esophageal SCC [adjusted odds ratio （AOR）： 0.315-0.472, all P-value 〈 0.05] but positively associated with gastric adenocarcinoma （both cardia and non-cardia） （AOR： 1.636-3.060, all P-value 〈 0.05） in comparison to the three control groups. Similar results were not found in cancers of the oral cavity and colon. CONCLUSION： Our findings support the finding that H pylori seropositivity is inversely associated with esophageal SCC risk, but increases the risk of gastric cardia adenocarcinoma.

Etiologic factors of gastric cardiac adenocarcinoma among men in Taiwan

AIM:To elucidate etiologic associations between Helicobacter pylori(H pylori),lifestyle,environmental factors and gastric cardiac adenocarcinoma(GCA)among men. METHODS:A hospital-based case-control study was conducted in Taiwan from 2000 to 2009.All cases were newly confirmed as primary GCA.Five controls were selected matching with age,sex,and admission date to each case.Participants were informedof potential risk factors with a structured question- naire by trained interviewers during hospitalization and provided a blood sample for the determination of H pylori infection.Odds ratio(OR)and 95%confidence interval(95%CI)were used to evaluate risk,and a multivariate conditional logistic regression model was performed. RESULTS:All participants recruited for this study were men,consisting of 41 cases and 205 controls.Results of the univariate analysis showed that significant factors associated with the etiology of GCA included H pylori(OR =2.69,95%CI=1.30-5.53),cigarette smoking(OR= 2.28,95%CI=1.05-4.96),working or exercising after meals(OR=3.26,95%CI=1.31-8.11),salted food (OR=2.51,95%CI=1.08-6.11),fresh vegetables(OR =0.28,95%CI=0.09-0.80),fruits(OR=0.19,95% CI=0.04-0.89),and rice as principal food(OR=0.53, 95%CI=0.30-0.85).Multivariate conditional logistic regression models indicated that a significantly elevated risk of contracting GCA was associated with working or exercising after meals(OR=3.18,95%CI=1.23-9.36) and H pylori infection(OR=2.93,95%CI=1.42-6.01). In contrast,the consumption of fresh vegetables(OR =0.22,95%CI=0.06-0.83),fruits(OR=0.28,95% CI=0.09-0.79)and rice as principal food(OR=0.48, 95%CI=0.24-0.93)remained as significant beneficial factor associated with GCA. CONCLUSION:Working or exercising after meals and H pylori infection increase the risk of GCA,but higher intakes of rice,fresh vegetables and fruits reduce the risk.

Study on Detection of Negative Corona Discharge Generated in Rod-Plane Air Gap by Using External Electrode Method

A detective method of a negative corona discharge by means of an external electrode is presented. The relationship between an area of the external electrode and a detected voltage waveform is examined experimentally. This experimental study is carried out with the use of a rod-plane air gap. The results obtained will be applicable to problems associated with silos, ducts, and high-voltage equipment.

A Study of Heavy Metals in the Dust Fall around Assiut Fertilizer Plant

A study of an environmental assessment of dust fall and the associated heavy metal contents was conducted during the period from the first of March 2011 to the end of February 2012 at adjoining area of a phosphate fertilizer plant. Around the industrial area 8 dust fall stations were established and one of them was built upwind far from pollution activities to be taken as a control sample. Dust fall samples collected monthly weighed and then prepared to be analyzed through Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) to obtain heavy metal concentration. Meteorological parameters influencing the distribution of dust fall such as wind speed and direction, temperature, humidity, rain fall and pressure were determined. Results showed that deposition flow rates were 38.2. 47.5, 57.7, 44.3, 39.4, 38.2, 42.7 and 5.9 g/m2·month for the sites No., 1, 2, 3, 4, 5, 6, 7 and 8 respectively, and were compared with the findings of other investigators of like industrial areas worldwide. Levels of heavy metal As, Cu, Pb, Zn, Cd, and Hg in the deposited dust fall were 3.30, 26.46, 22.33, 235.00, 4.53 and 3.80 μg/g respectively. Enrichment coefficients of the heavy metals in the dust fall were found to be significant and reached the values 1.81, 0.90, 0.85, 0.65, 0.41 and 0.35 for zinc, lead, cadmium, copper, mercury and arsenic respectively. The paper ends with results and recommendations suggesting a methodology to remediate the investigated area polluted with heavy metals and control measures for the fertilizer plant to reduce pollution into the surrounding environment.

桩基支撑的塔式起重机在软粘土桩基中的地震响应分析（英文）

临时结构房屋的抗震性能次于永久结构房屋。桩基支撑的塔式起重机是一种临时结构,常被应用于建造高层建筑。安装在高处的塔式起重机,因其是高柔结构,在强地震动的作用下很可能会产生剧烈震荡。桩基结构的地震响应特性受周围的地基和基础类型的影响也较大。在当前日本的设计规范中,地震荷载仅仅被定义为20%的起重机结构重量,都没有充分考虑待结构的动态不稳定性和周围的地基类型。为探究塔式起重机在软粘土桩基中的抗震特性,开展了一系列的离心振动台试验。为起重机吊臂制定了2种不同的荷载条件来准确地模拟实际情况。根据测试结果,对塔式起重机的动力响应行为和影响的因素进行了讨论,得到如下结论:起重机臂架的荷载条件对桩的损伤程度有显著影响,并可以导致塔式起重机不同的破坏模式。

急流异常可能是M>6.0地震的短期前兆

热图像的卫星数据揭示了与地壳断层大线性结构和系统相关的热场的存在。所测量的长波辐射高度正好落在急流区间内。本工作描述了两个区域范围内强震和急流之间可能存在的联系。在2006~2010年强震（M〉6.0）震中附近,气流的前端或尾端位置能在震中附近保持6个小时甚至更久。在一张6小时气象图上有93.6%的几率可以观测到稳定的急流,而在两张邻接的气象图上看到这种变化的几率是26.7%。震中和急流位置分布的中位数为36.5km。能实现预测的累积概率估算值如下：10天为24.2%,20天为48.4%,30天为66.1%,40天为87.1%,50天为93.5%,70天为100%。观测到的前兆效应可能会引起地震实际短临预报应用者的极大兴趣。

吸烟者肺局部IgA变化及对抗原的免疫应答

目的 研究吸烟对年轻吸烟者肺局部免疫功能的损害。方法 对 12名健康志愿者 (其中 5名吸烟 )行右肺中叶肺灌洗 (BAL) ,分析肺灌洗 (BALF)中IgA型别、细胞分类计数、白蛋白含量 ,并从左肺舌肺叶内注入钥孔血蓝蛋白抗原 ,观察肺局部抗原免疫后血循环中特异性IgA抗体的免疫应答能力。结果 吸烟者BALF中单体IgA含量、白细胞数、巨噬细胞数显著高于不吸烟者 ,而双体IgA含量未见增加 ;BALF中单体IgA含量与白蛋白含量、白细胞数量呈正相关。肺局部抗原免疫后血清特异性IgA应答表现为抗体出现晚、峰值低、下降早的特点。结论 早期吸烟可引起年轻吸烟者支气管肺泡炎症反应并导致肺局部免疫应答功能损害。

温石棉诱发人胚肺细胞恶性转化中端粒酶的作用

目的 研究端粒酶在石棉诱发人胚肺成纤维细胞恶性转化中的作用。方法 将端粒酶基因功能片段 (hTERT)导入人胚肺成纤维细胞 (HELF)中。选用 2 5 μg/cm2 温石棉粉尘分别对导入和未导入hTERT的HELF进行染毒 ,分离转化灶 ,观察细胞生物性状 ,测定细胞生长曲线、端粒酶活性和端粒长度 ,进行软琼脂集落形成实验 ,判定转化性质。结果 将hTERT成功导入HELF ,建立了导入端粒酶功能片段的人胚肺成纤维细胞系 (HELF T+ )。HELF和HELF T+ 被石棉刺激后均发生了恶性转化 ,HELF T+ 恶性转化率为 (2 0 8± 1 0 8)转化灶 /皿 ,显著高于HELF染毒组的恶性转化率 [(1 0 8±0 10 )转化灶 /皿 ]。恶性转化的细胞和HELF T+ 均具有较高的端粒酶活性和较长的端粒长度。结论 端粒酶活性较高、端粒长度较长的细胞 ,经石棉刺激后恶性转化率也较高 。