Laboratory study of heterogeneous ice nucleation in deposition mode of montmorillonite mineral dust particles aged with ammonia, sulfur dioxide, and ozone at polluted atmospheric concentrations

Heterogeneous ice nucleation in deposition mode of montmorillonite mineral dust aerosol particles exposed to atmospheric trace gases (ammonia, sulfur dioxide, and ozone) was studied at temperatures warmer than −40°C with a continuous flow diffusion chamber. Pure and typical polluted atmospheric concentrations of ammonia, sulfur dioxide, and ozone gases were used to age montmorillonite mineral dust aerosol particles at room temperature and atmospheric pressure in a stainless steel chamber. Ammonia-, sulfur dioxide-, and ozone-exposed montmorillonite mineral dust aerosols act as ice nuclei in heterogeneous deposition freezing at warmer temperatures than required for homogeneous freezing. The ice nucleation efficiency of montmorillonite mineral dust aerosols increased about two times due to exposure to ammonia at a typical atmospheric concentration of about 100 ppt. This is the first experimental evidence for the enhancement of the ice nucleation efficiency of montmorillonite mineral dust aerosols by ammonia gas at typical atmospheric concentrations. Montmorillonite exposure to either pure (100%) or 45 ppm sulfur dioxide or to ozone at 200 ppb shows no clear evidence for changing the ice nucleation efficiency of montmorillonite mineral dust particles. Thus, we conclude that enhancements atmospheric trace gases (e.g., sulfur dioxide and ozone) due to anthropogenic activities have no significant impact on the heterogeneous ice nucleation of montmorillonite mineral dust particles.     

Ozone air pollution and daily mortality in Genoa, Italy between 1993 and 1996

The association between ozone (O3) and daily mortality was investigated in Genoa, an Italian city characterized by a Mediterranean climate and a high prevalence of elderly inhabitants. The O3 effect, adjusted for long time trend, seasonality and weather, was assessed using Poisson regression modelling, allowing for overdispersion and autocorrelation, and expressed as mean variation percent of daily mortality per 50 microg/m3 increase (MV). Significant MVs for overall (+4.0%) and cardiovascular (+7.2%) mortality were detected at 1-day lag. The effects were stronger in the warmer season (May-October). Similar estimates were found after restricting the analyses to the elderly (>or=75 years). Furthermore, in this group, higher MVs were observed for total mortality at 2-day lag. A statistically significant synergistic effect between O3 and temperature was observed for cardiovascular mortality, particularly in elderly people, with an evident increase in mortality risk above 26 degrees C (MV +30.0% for the whole population and +40.0% for the elderly, respectively). This investigation highlights the importance of taking local climatic and demographic features into account when comparing different time-series studies, and substantiates the influence of photochemical pollution on mortality trends in small urban areas.     

Potential Oxidative Stress in the Bodies of Electric Arc Welding Operators： Effect of Photochemical Smog

INTRODUCTION Electric arc welding is widely used in many fields such as welding engineering, architectural engineering, automotive industry, boat and ship engineering, aerospace C…     

Postnatal remodeling of the neural components of the epithelial-mesenchymal trophic unit in the proximal airways of infant rhesus monkeys exposed to ozone and allergen

Nerves and neuroendocrine cells located within the airway epithelium are ideally situated to sample a changing airway environment, to transmit that information to the central nervous system, and to promote trophic interactions between epithelial and mesenchymal cellular and acellular components. We tested the hypothesis that the environmental stresses of ozone (O(3)) and house dust mite allergen (HDMA) in atopic infant rhesus monkeys alter the distribution of airway nerves. Midlevel bronchi and bronchioles from 6-month-old infant monkeys that inhaled filtered air (FA), house dust mite allergen HDMA, O(3), or HDMA + O(3) for 11 episodes (5 days each, 0.5 ppm O(3), 8 h/day followed by 9 days recovery) were examined using immunohistochemistry for the presence of Protein gene product 9.5 (PGP 9.5), a nonspecific neural indicator, and calcitonin gene-related peptide (CGRP). Along the axial path between the sixth and the seventh intrapulmonary airway generations, there were small significant (P < 0.05) decrements in the density of epithelial nerves in monkeys exposed to HDMA or O(3), while in monkeys exposed to HDMA + O(3) there was a greater significant (P < 0.05) reduction in epithelial innervation. In animals exposed to O(3) or HDMA + O(3) there was a significant increase in the number of PGP 9.5 positive/CGRP negative cells that were anchored to the basal lamina and emitted projections in primarily the lateral plain and often intertwined with projections and cell bodies of other similar cells. We conclude that repeated cycles of acute injury and repair associated with the episodic pattern of ozone and allergen exposure alter the normal development of neural innervation of the epithelial compartment and the appearance of a new population of undefined PGP 9.5 positive cells within the epithelium.     

臭氧与胶原酶治疗腰椎间盘突出症的临床比较

目的比较和评价臭氧消融术与胶原酶化学溶解术治疗腰椎间盘突出症的疗效。方法142例腰椎间盘突出症患者,根据治疗方法不同分为2组,Ⅰ组70例,Ⅱ组72例。Ⅰ组采用臭氧消融术治疗,Ⅱ组采用胶原酶溶解术治疗。随访1周、3个月、6个月比较两组治疗效果。结果治疗后1周Ⅰ组、Ⅱ组的优良率分别为85.7%(60/70例)、68.1%(49/72例),术后随访,于3个月、6个月时的优良率Ⅰ组分别为88.6%(62/70例)、90.0%(63/70例),Ⅱ组为88.9%(64/72例)、91.7%(66/72例),两组疗效于治疗后1周时优良率的差异有统计学意义(P<0.05),3个月和6个月后优良率对比的差异无统计学意义(P>0.05)。结论臭氧消融术和胶原酶溶解术均为治疗腰椎间盘突出症的有效疗法。臭氧消融术的近期疗效明显优于胶原酶溶解术,但远期疗效两组差异无统计学意义。     

椎间盘突出症不同治疗方法回顾性分析

目的分析臭氧髓核消溶术（A组）、后路开窗髓核摘除术（B组）以及胶原酶化学髓核消溶术（C组）治疗椎间盘突出症的方法和后期效果。方法采用统一的病例选择和疗效标准,对185例患者（其中A组60例,B组63例,C组62例）进行分析,比较3组治疗后评分和优良率。结果A组治疗后评分和优良率明显高于B组和C组,有非常显著性差异（P〈0.01）,B组高于C组有显著性差异（P〈0.05）。结论椎间盘突出症不同治疗方法中,臭氧髓核消溶术和胶原酶化学髓核消溶术明显优于开窗髓核摘除术,具有基本无创的优点。而开窗髓核摘除术相对而言创伤较大,对脊柱的稳定性有一定的影响。臭氧髓核消溶术是椎间盘突出症治疗方法中最理想的方法。     

Ozone and allergen exposure during postnatal development alters the frequency and airway distribution of CD25+ cells in infant rhesus monkeys

The epidemiologic link between air pollutant exposure and asthma has been supported by experimental findings, but the mechanisms are not understood. In this study, we evaluated the impact of combined ozone and house dust mite (HDM) exposure on the immunophenotype of peripheral blood and airway lymphocytes from rhesus macaque monkeys during the postnatal period of development. Starting at 30 days of age, monkeys were exposed to 11 cycles of filtered air, ozone, HDM aerosol, or ozone + HDM aerosol. Each cycle consisted of ozone delivered at 0.5 ppm for 5 days (8 h/day), followed by 9 days of filtered air; animals received HDM aerosol during the last 3 days of each ozone exposure period. Between 2-3 months of age, animals co-exposed to ozone + HDM exhibited a decline in total circulating leukocyte numbers and increased total circulating lymphocyte frequency. At 3 months of age, blood CD4+/CD25+ lymphocytes were increased with ozone + HDM. At 6 months of age, CD4+/CD25+ and CD8+/CD25+ lymphocyte populations increased in both blood and lavage of ozone + HDM animals. Overall volume of CD25+ cells within airway mucosa increased with HDM exposure. Ozone did not have an additive effect on volume of mucosal CD25+ cells in HDM-exposed animals, but did alter the anatomical distribution of this cell type throughout the proximal and distal airways. We conclude that a window of postnatal development is sensitive to air pollutant and allergen exposure, resulting in immunomodulation of peripheral blood and airway lymphocyte frequency and trafficking.     

激光加臭氧联合治疗椎间盘源性下腰痛初步研究

目的：评价联合应用经皮穿刺激光加臭氧对椎间盘源性下腰痛的治疗效果。方法：椎间盘源性下腰痛患者48例,男32例,女16例;年龄21～66岁,平均43.5岁;病程6个月以上。所有病例均在X线电视导向下联合应用经皮穿刺激光髓核消融加臭氧治疗。结果：术后随访无严重并发症发生。根据Macnab腰腿痛手术评价标准,术后1周时优8例,良28例,可8例,差4例,优良率75%;3个月时优17例,良23例,可6例,差2例,优良率83.3%;6个月时优20例,良22例,可4例,差2例,优良率87.5%;12个月时优21例,良22例,可4例,差1例,优良率89.6%。结论：联合应用经皮穿刺激光加臭氧治疗椎间盘源性下腰痛的疗效确切。     

臭氧和固定化微生物对黄腐酸氯化前,后致突变性的影响

为探索降低饮水致突变活性的途径，通过Ａｍｅｓ试验，对经臭氧和／或固定化微生物预处理的黄腐酸氯化前后形成的非挥发性有机物致突变性进行对比研究。研究表明，黄腐酸直接氯化后形成的ＮＶＯＣ致突变性为阳性，主要形成移码突变型直接致突变性；其它处理方式形成的ＮＯＶＣ致突变性为阴性。     

臭氧对外科切口杀菌作用的实验研究

为探讨臭氧对外科切口的抗感染作用及对创面愈合的影响,本实验建立动物肛周及背部切口模型,用臭氧水、双氧水及碘伏消毒切口,对比三种消毒剂的消毒效果及对创面愈合的影响。结果显示,臭氧水与双氧水及碘伏相比,其消毒效果更强,创面愈合时间更短。结果表明,臭氧水是一种相对更好的消毒制剂。