首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 11 毫秒
1.
目的: 分析玉林市空气污染物与气象因素对肺结核发病的影响及交互作用。方法: 收集2017年1月1日至2021年12月31日广西壮族自治区玉林市11251例新发肺结核患者的病例资料;同时,收集同期玉林市空气污染物及气象因素资料。采用Spearman相关性分析方法分析同期空气污染物和气象因素与肺结核发病的相关性;采用双变量响应面模型、单污染物-气温交互模型分析空气污染物与气温对肺结核发病风险的交互作用。结果: 2017—2021年玉林市肺结核的发病具有明显的季节波动性,高峰集中在春季(27.57%,3102/11251)和夏季(27.89%,3138/11251);男性和农民发病占比较高,分别为74.70%(8405/11251)和87.74%(9872/11252)。2017—2021年玉林市每日空气污染物PM2.5、PM10、SO2、NO2、CO、O3浓度[中位数(四分位数)]分别为27.00(19.00,41.00)μg/m3、44.00(32.00,64.00)μg/m3、13.00(8.00,21.00)μg/m3、15.00(12.00,21.00)μg/m3、0.82(0.69,0.99)mg/m3、53.00(39.00,69.00)μg/m3;每日气温[中位数(四分位数)]为24.50(19.00,29.00)℃;肺结核日均发病6例(11251/1825)。高温(37.00℃)在滞后0~4d时可使玉林市人群肺结核发病数增高,相比于每日气温的中位数(24.50℃,RR值为1.00),37.00℃累计0~4d的RR值为1.20;低温(3.00℃)在滞后0~2d时也可使玉林市人群肺结核发病数增高,相比于每日气温的中位数(24.50℃,RR值为1.00),3.00℃累计0~2d的RR值为1.22。低温(3.00℃)时PM2.5、PM10、NO2、CO对肺结核发病数影响的效应较强,高温(37.00℃)时PM2.5、PM10、SO2、NO2、CO、O3对肺结核发病数影响的效应较弱。结论: 高温暴露或低温暴露可引起玉林市肺结核发病风险升高,尚未发现气象因素与空气污染物对玉林市肺结核发病风险存在协同作用。  相似文献   

2.
The processes of carbon erosion of nickel alloys during the catalytic pyrolysis of organic compounds with the formation of carbon nanofibers in a flow-through reactor as well as under reaction conditions in a close volume (Reactions under Autogenic Pressure at Elevated Temperature, RAPET) were studied. The efficiency of the ferromagnetic resonance method to monitor the appearance of catalytically active nickel particles in these processes has been shown. As found, the interaction of bulk Ni-Cr alloy with the reaction medium containing halogenated hydrocarbons (1,2-dichloroethane, 1-iodobutane, 1-bromobutane) results in the appearance of ferromagnetic particles of similar dimensions (~200–300 nm). In the cases of hexachlorobenzene and hexafluorobenzene, the presence of a hydrogen source (hexamethylbenzene) in the reaction mixture was shown to be highly required. The microdispersed samples of Ni-Cu and Ni-Mo alloys were prepared by mechanochemical alloying of powders and by reductive thermolysis of salts-precursors, accordingly. Their interaction with polymers (polyethylene and polyvinyl chloride) under RAPET conditions and with ethylene and 1,2-dichloroethane in a flow-through reactor are comparatively studied as well. According to microscopic data, the morphology of the formed carbon nanofibers is affected by the alloy composition and by the nature of the used organic substrate.  相似文献   

3.
This paper aims to study the suitability of partial replacement of lime by waste originating from the cleaning of flue gases from the combustion of industrial wastes in the production of autoclaved aerated concrete (AAC). The compressive strength, bulk density, pore structure, phase composition, and microstructure of hydration products of the AAC were analyzed. According to the results, the addition of the waste can effectively enhance the mechanical properties of AAC due to the differences in morphology of hydration product—1.1 nm tobermorite and related dense microstructure. The pore size distribution was significantly influenced by waste addition, which was one of the main reasons for the increase in thermal conductivity. The XRD and SEM results showed that foreign ions introduced with the wastes affect the synthesis of 1.1 nm tobermorite. Moreover, it was shown that waste containing a high content of CaO can be used as lime replacement, which allows reducing CO2 emissions during the AAC production process.  相似文献   

4.
In order to reuse red mud and bauxite tailings mud (two typical aluminum industrial wastes) to reduce the occupation of land resources and environmental damage, these two wastes were combined to develop subgrade materials for the first time. With different combinations, the effects of the amounts of red mud, tailings mud, and cementitious materials on the strength of tested subgrade materials were investigated. The mechanism of strength growth was analyzed by a micro-test. The test results showed that the material strength of three combinations met the requirements when the unconfined compression strength (UCS) of all combinations increased with age. The UCS of the A1BC2 combination (the mass ratio of red mud and tailings mud was 2:1, the mass ratio of cement and quicklime was 1:1, and the mass ratio of waste and cementitious materials was 1:0.2) was the best, with the UCS being 3.03 MPa in 7 days. Microscopic imaging showed that specimens with high red mud contents had compact structures without cracks. The strength of these materials is mainly due to hydration reactions and pozzolanic reactions; the cementitious products generated by the reactions solidify Na+ and inhibit the release of OH, while the addition of tailings mud can reduce the content of Na2O in the material, which makes the environmental compatibility of the A3BC2 combination the best (the mass ratio of red mud and tailings mud was 1:2, the mass ratio of cement and quicklime was 1:1, and the mass ratio of waste and cementitious materials was 1:0.2). Its pH value was 8.75. This experiment verifies the feasibility of the combined application of red mud and tailings mud in subgrade materials. To this end, a feasible scheme for the simultaneous consumption of these two kinds of aluminum industrial wastes has been proposed.  相似文献   

5.
The effect of isothermal conditions on the trapping/detrapping process of charges in e-beam irradiated thermally aged XLPE insulation in scanning electron microscopy (SEM) has been investigated. Different isothermal conditions ranging from room temperature to 120 °C are applied on both unaged and aged XLPE samples (2 mm thick) by a suitable arrangement associated with SEM. For each applied test temperature, leakage, and influence currents have been measured simultaneously during and after e-beam irradiation. Experimental results show a big difference between the fresh and aged material regarding trapping and detrapping behavior. It has been pointed out that in the unaged material deep traps govern the process, whereas the shallow traps take part in the aged one. Almost all obtained results reveal that the trapped charge decreases and then increases as the temperature increases for the unaged sample. A deflection temperature corresponding to a minimum is observed at 50 °C. However, for the aged material, the maximum trapped charge decreases continuously with increasing temperature, and the material seems to trap fewer charges under e-beam irradiation at high temperature. Furthermore, thermal aging leads to the occurrence of detrapping process at high temperatures even under e-beam irradiation, which explains the decrease with time evolution of trapped charge during this period. The recorded leakage current increases with increasing temperature for both cases with pronounced values for aged material. The effect of temperature and thermal aging on electrostatic influence factor (K) and total secondary electron emission yield (σ) were also studied.  相似文献   

6.
The review presents advances in the removal of Cr(III) from the industrial effluents published in the last ten years. Although Cr(III) has low solubility and is less dangerous for the aquatic environment than Cr(VI), it cannot be released into the aquatic environment without limitations and its content in water should be restricted. The development of efficient techniques for the removal of Cr(III) is also a response to the problem of chromium wastewater containing Cr(VI) ions. Very often the first step in dealing with such wastewater is the reduction in chromium content. In some cases, removal of Cr(III) from wastewaters is an important step for pretreatment of solutions to prepare them for subsequent recovery of other metals. In the review, hydrometallurgical operations for Cr(III) removal are presented, including examples of Cr(III) recovery from real industrial effluents with precipitation, adsorption, ion exchange, extraction, membrane techniques, microbial-enhanced techniques, electrochemical methods. The advantages and disadvantages of the operations mentioned are also presented. Finally, perspectives for the future in line with circular economy and low-environmental impact are briefly discussed.  相似文献   

7.
In order to explore the cracking law and failure characteristics of segments, a model test of shield segment cracking was conducted. The microscopic and macroscopic crack evolution process of the segment is studied by using acoustic emission detection technology and crack opening displacement (CMOD). According to the acoustic emission signal and CMOD, characteristics generated in the process of segment cracking, in the form of numerical value, the evolution characteristics of each stage of segment cracking are directly reflected. Based on acoustic emission energy and CMOD, the segment cracking damage model was established to determine the segment fracture damage degree. The result shows that segment cracking can be divided into three stages, and the acoustic emission detection results and CMOD have different degrees of change in each cracking stage. This proves that both the acoustic emission acquisition results and CMOD can be used as evaluation indicators of damage degree. Acoustic emission can accurately identify the crack evolution process, and the yield strengthening is an important stage of crack damage evolution. The damage data points in this stage account for 76.83% of all the damage data points, the occurrence rate of damage data points is 0.225 s, and the density of data points in the damaged area is 3.219 × 10−4 mm3, which is larger than the other two stages. The segment cracking damage model can effectively reflect the segment cracking degree and provide a reference for the actual segment cracking assessment.  相似文献   

8.
9.
The extracellular release from human neutrophils of the primary (azurophil) granule constituents, myeloperoxidase (MPO), chymotrypsin-like cationic protein (CCP), col-lagenase and lysozyme, and the secondary (specific) granule constituents, lactoferrin and lysozyme, was measured during ingestion of staphylococcus protein-A-IgG complexes. In buffer, lactoferrin release was consistently higher than that of the other protein. In serum, lactoferrin release increased concomitantly with ingestion, whereas the rate of lysozyme and especially of MPO release were stimulated to a higher degree than ingestion. Magnesium (0.5-2 mM) was more potent than calcium (0.5-2 mM) in promoting release but these cations worked synergistically. Zinc (0.5-4 mM) was found to be a potent and selective inhibitor of collagenase release. Manganese (0.25-4 mM), which inhibited the ingestion of SpA-IgG complexes, also inhibited release of CCP, collagenase, lysozyme and MPO, but actually stimulated lactoferrin release. The data suggests that lactoferrin and lysozyme may be confined to distinct granule populations or else released in a different fashion from the granules. When the effects on release of primary granule proteins are concerned it is suggested that the dissociation of binding of various agents to an anionic granule matrix may be affected differently by various cations.  相似文献   

10.
11.
The ability of terrestrial microorganisms to grow in the near-surface environment of Mars is of importance to the search for life and protection of that planet from forward contamination by human and robotic exploration. Because most water on present-day Mars is frozen in the regolith, permafrosts are considered to be terrestrial analogs of the martian subsurface environment. Six bacterial isolates were obtained from a permafrost borehole in northeastern Siberia capable of growth under conditions of low temperature (0 °C), low pressure (7 mbar), and a CO2-enriched anoxic atmosphere. By 16S ribosomal DNA analysis, all six permafrost isolates were identified as species of the genus Carnobacterium, most closely related to C. inhibens (five isolates) and C. viridans (one isolate). Quantitative growth assays demonstrated that the six permafrost isolates, as well as nine type species of Carnobacterium (C. alterfunditum, C. divergens, C. funditum, C. gallinarum, C. inhibens, C. maltaromaticum, C. mobile, C. pleistocenium, and C. viridans) were all capable of growth under cold, low-pressure, anoxic conditions, thus extending the low-pressure extreme at which life can function.  相似文献   

12.
目的探讨日本血吸虫门脉内童虫表膜抗原(SjHmAg)的免疫特性,观察其抗日本血吸虫(Sj)的保护效果。方法用SDS-PAGE电泳技术分析SjHmAg蛋白组分,酶联免疫电转移印迹(EITB)分析感染兔血清(IRS)和正常兔血清(NRS)对SjHmAg的识别;用完整SjHmAg免疫昆明鼠3次,分别在0、2、4周进行,第6周每鼠经腹部感染40±1条Sj尾蚴,42天后剖杀,计数虫数及肝卵数。结果用SDS-PAGE电泳获得SjHmAg主带7条,IRS主要能识别SjHmAg23、33和63kDa等10个抗原组分;间接ELISA测其抗体滴度>1:6400,与对照组相比,SjHmAg免疫小鼠的减虫率为16.2%,减卵率为55.4%。结论用SDS-PAGE获得了不同分子量的SjHmAg蛋白,EITB鉴别出具有免疫活性的蛋白分子,且SjHmAg对Sj攻击感染及雌虫生植似有一定的抗性。  相似文献   

13.
目的 了解手足口病患者家庭密切接触者肠道病毒感染情况及其家庭环境物品肠道病毒污染情况.方法 选取广东省2010年7-8月疾病监测报告信息系统报告的41例手足口病实验室确诊的普通患者,人户调查患者家庭全部成员人口学信息、家庭卫生习惯及卫生状况,采集患者家庭全部成员粪便标本及16户家庭物品表面涂抹标本,进行人肠道病毒实时荧光定量PCR检测,数据采用卡方检验和t检验.结果 完成调查41户手足口病患者家庭及135名家庭密切接触者,密切接触者肠道病毒阳性53名,阳性率为39.2%;24户患者家庭的密切接触者肠道病毒检测阳性,占58.5%;4户家庭全部成员肠道病毒检测均为阳性,占9.8%.按父母、(外)祖父母及叔婶姨舅、亲(表、堂)兄弟姐妹区分的肠道病毒阳性率分别为32.5%(25/77)、43.3%(13/30)和53.6%(15/28),差异无统计学意义(χ2=4.07,P=0.131);家庭人数≥5名的患者家庭的密切接触者肠道病毒阳性率高于≤4名者(OR=1.4,95%CI:1.1~1.9).135名家庭密切接触者中,有37名与家庭内患者感染病毒型别一致,占27.4%;16名与家庭内患者感染病毒型别不一致,占11.9%.采集16户家庭玩具等表面涂抹标本共33份,其中2份玩具检出肠道病毒,阳性率为6.1%.密切接触者肠道病毒检测阴性和阳性的手足口病患者家庭分别有17户和23户,其看护儿童前洗手、餐饮具消毒、共用面巾、晾晒床上用品及玩具清洗等卫生习惯差异均无统计学意义(均P>0.05).结论 手足口病患者家庭密切接触者肠道病毒阳性率较高,居家环境存在肠道病毒污染;应做好患者家庭密切接触者的管理和居家环境的消毒.  相似文献   

14.
Application of additives to waste may influence the course of the biostabilization process and contribute to its higher effectiveness, as well as to a reduction in greenhouse gas and ammonia (NH3) emission from this process. This paper presents research on the impact of biochar addition on the course of the biostabilization process of an undersized fraction from municipal solid waste (UFMSW) in terms of temperature changes, CO2 concentration in the exhaust gases, NH3 emission from the process, as well as changes in the carbon and nitrogen content in the processed waste. Six different biochar additives and three different air-flow rates were investigated for 21 days. It was found that biochar addition contributes to extending the thermophilic phase duration (observed in the case of the addition of 3% and 5% of biochar). The concentration of CO2 in exhaust gases was closely related to the course of temperature changes. The highest concentration of CO2 in the process gases (approx. 18–19%) was recorded for the addition of 10% and 20% of biochar at the lowest air-flow rate applied. It was found that the addition of 3% or a higher amount of biochar reduces nitrogen losses in the processed UFMSW and reduces NH3 emission by over 90% compared to the control.  相似文献   

15.
目的 探讨低密度脂蛋白免疫复合物对小鼠腹腔巨噬细胞胆固醇酯的蓄积和一氧化氮释放的影响。方法 密度梯度超速离心从新鲜人血浆分离天然低密度脂蛋白,与抗低密度脂蛋白抗血清IgG组分制备低密度脂蛋白免疫复合物,低密度脂蛋白免疫复合物与小鼠腹腔巨噬细胞孵育后采用酶荧光法检测细胞胆固醇酯含量,进行细胞形态学观察和组织化学分析.并用硝酸还原酶法测定细胞释放至培养基中的一氧化氮量。结果 低密度脂蛋白免疫复合物剂量依赖性地诱导巨噬细胞内胆固醇酯的大量堆积,其效应显著强于氧化型低密度脂蛋白(P〈0.01)。经低密度脂蛋白免疫复合物处理的巨噬细胞呈典型泡沫细胞状,与猩红强染色,而天然低密度脂蛋白、抗低密度脂蛋白IgG处理的巨噬细胞内未见胆固醇酯的蓄积。此外,低密度脂蛋白免疫复合物剂量依赖性地抑制巨噬细胞一氧化氮的分泌。结论 低密度脂蛋白免疫复合物不仅通过致小鼠腹腔巨噬细胞泡沫化,也通过损伤巨噬细胞分泌一氧化氮的功能参与致动脉粥样硬化作用。  相似文献   

16.
17.
Sedimentation is a naturally occurring process of allowing particles in water bodies to settle out of the suspension under a gravity effect. In this study, the sediments of the Drava River were fully investigated to determine the heavy metal concentrations along the river and their potential reuse in the construction sector. Naturally dehydrated sediments from the Drava River were tested as an additive for the production of fired bricks. The dredged sediments were used as a substitute for natural brick clay in amounts up to 50% by weight, and it was confirmed that up to 20% by weight of the added sediment could be used directly in the process without critically affecting performance. Finally, the naturally dehydrated sediments were also evaluated for their use as a filling material in the construction of levees. The natural moisture content of the dehydrated sediment was too high for it to be used without additives, so quicklime was added as an inorganic binder. The test results showed an improvement in the geotechnical properties of the material to such an extent that it is suitable as a filling material for levees.  相似文献   

18.
Distribution of gasses to the cast volume and volume of pores can be maintained within the acceptable limits by means of correct setting of technological parameters of casting and by selection of suitable structure and gating system arrangement. The main idea of this paper solves the issue of suitability of die casting adjustment—i.e., change of technological parameters or change of structural solution of the gating system—with regards to inner soundness of casts produced in die casting process. Parameters which were compared included height of a gate and velocity of a piston. The melt velocity in the gate was used as a correlating factor between the gate height and piston velocity. The evaluated parameter was gas entrapment in the cast at the end of the filling phase of die casting cycle and at the same time percentage of porosity in the samples taken from the main runner. On the basis of the performed experiments it was proved that the change of technological parameters, particularly of pressing velocity of the piston, directly influences distribution of gasses to the cast volume.  相似文献   

19.
It is widely accepted that environmental degradation and poverty are linked and that conservation and poverty reduction should be tackled together. However, success with integrated strategies has been elusive. Here, we present the results of a study that illustrates how development that combines environmental and economic perspectives and that provides appropriate compensation to affected populations can improve both nature and society, thereby eradicating the “poverty trap.” The results show that if we cannot improve the livelihood of local residents, we will be unable to restore degraded environments when state-owned property is transferred to private ownership to encourage better management by residents. In contrast, measures to eliminate poverty, combined with the development of green enterprises that improve the livelihoods of private land owners in the long term, is the precondition for successful ecological restoration.  相似文献   

20.
To enable standardisation of care of pancreatic cancer patients and facilitate improvement in outcome, the United Kingdom's National Institute for Health and Care Excellence (NICE) developed a clinical guideline for the diagnosis and management of pancreatic cancer in adults. Systematic literature searches, systematic review and meta-analyses were undertaken. Recommendations were drafted on the basis of the group's interpretation of the best available evidence of clinical and cost effectiveness. There was patient involvement and public consultation. Recommendations were made on: diagnosis; staging; monitoring of inherited high risk; psychological support; pain; nutrition management; and the specific management of people with resectable-, borderline-resectable- and unresectable-pancreatic cancer. The guideline committee also made recommendations for future research into neoadjuvant therapy, cachexia interventions, minimally invasive pancreatectomy, pain management and psychological support needs. These NICE guidelines aim to promote best current practice and support and stimulate research and innovation in pancreatic cancer.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号