Investigating the Link between Particulate Exposure and Airway Inflammation in the Horse

Inhalant exposure to airborne irritants commonly encountered in horse stables is implicated in the pathogenesis of inflammatory airway disease (IAD) and recurrent airway obstruction (RAO), non‐infectious, inflammatory pulmonary disorders that impact the health and performance of horses across all equine disciplines. IAD and RAO have overlapping clinical, cytological, and functional manifestations of the pulmonary response to organic dust and noxious gases encountered in the barn environment. Study of these diseases has provided important but incomplete understanding of the effect of air quality upon the respiratory health of horses. In this review, the principles of particulate exposure assessment, including health‐related aerosol size fractions and size‐selective sampling, the factors influencing air quality in equine environments, and the effect of air quality on the equine respiratory tract are discussed. The objective of this review is to provide the reader with a summary of the most common chronic inflammatory airway diseases in the horse and the principles of air sampling that are essential to the planning, interpretation, and assessment of equine respiratory health‐related exposure studies.     

Influence of smoke exposure on soil enzyme activities and nitrification

Summary Soil was exposed to red phosphorous/butyl rubber (RP/BR) aerosols at various relative humidities in a recirculating environmental wind tunnel. Soil microbial and enzymatic activities were measured immediately after exposure and periodically thereafter for 56 days. The nitrification potential was significantly reduced in soil amended with ammonium sulfate and exposed to RP/BR smoke, and could be related to a decline in soil pH. The rate of nitrate formation in unamended soil with time was also reduced, but by 57 days postexposure, concentrations were similat to those of unexposed controls in all but the thinnest soil lense. Soil dehydrogenase and phosphatase enzyme activities were sensitive to RP/BR smoke and in some treatments no activity was detected. The measured activities did not recover within the 56-day postexposure period and in some cases declined. Soil lense thickness was the greatest factor controlling the degree of RP/BR effects, indicating that injury to soil microbial and enzymatic activities may be surficial. Deposition of smoke particles increased with increasing relative humidity, which had a significant impact on the activities measured.     

大气气溶胶介电常数的研究

由于气溶胶的介电常数不易直接测量,气溶胶的复折射指数的实部与其介电常数之间存在的一定关系,利用这一关系,可以用气溶胶的复折射指数的实部来求出其介电常数,并对4种基本粒子、3种常见类型的气溶胶以及任意体积比混和建立的气溶胶类型的介电常数进行了研究。     

牛舍空气微生物及向环境传播的研究

采用４ 台 Ａ Ｎ Ｄ Ｅ Ｒ Ｓ Ｅ Ｎ微生物空气样品收集器对一个犊牛舍内及环境空气细菌含量进行了测量, 需氧菌总数分别为８５３６ ～４６６９１ Ｃ Ｆ Ｕ／ｍ ３ 和２６４９ ～２４７７５ Ｃ Ｆ Ｕ／ｍ ３ , 厌氧菌浓度计３０１７ ～２４７７５ Ｃ Ｆ Ｕ／ｍ ３ 和６６１ ～４１２２ Ｃ Ｆ Ｕ／ ｍ３ 。根据 Ｈ Ｅ Ｓ Ｋ Ｅ Ｔ Ｈ （１９７４） 计算公式和 Ｋ Ｌ Ｕ Ｇ （１９６９） 气溶胶颗粒扩散模式, 得出犊牛舍菌源强度, 即向环境排放需氧菌为１１００００ ～１４００００ Ｃ Ｆ Ｕ／ｓ , 厌氧菌在２７０００ ～１７５０００ Ｃ Ｆ Ｕ／ｓ 之间。细菌浓度实际测量值与估算一致, 该公式和扩散模式适合于动物舍菌源强度和舍外环境不同距离空气微生物浓度的估算。距离犊牛舍１００ ｍ 下风处, 需氧菌高达６５０ ～８３９ Ｃ Ｆ Ｕ／ｍ ３ , 厌氧菌１６０ ～１０３４ 细菌／ｍ ３ , 各项均超过正常值１０ ～１５ 倍。     

Insect spiracle as the main penetration route of pyrethroids

The penetration route of adhered pyrethroids following direct aerosol spraying was studied in the German cockroach (Blattella germanica) by investigating the relationship between the application site of insecticide and knockdown efficacy. In direct spray, KT₅₀ was 26.4 s and the adhered amount of pyrethroid was 0.745 μg. On the contrary, required amount of pyrethroid to obtain the same KT₅₀ was one-eighth in topical application to the mesothoracic spiracle, while 2.6 times to the ventral mesothorax. KT₅₀ of cockroaches with blocked mesothoracic spiracles was greater than those with unblocked spiracles by 1.8-fold. The amount of directly sprayed pyrethroid penetrating through the inner wall of the mesothoracic trachea was significantly higher than the amount penetrating through the body wall of the ventral mesothorax. Therefore, the knockdown effect of the direct spray was believed to be caused by the flow of pyrethroids into the mesothoracic spiracles and its subsequent penetration through the inner wall of the mesothoracic trachea.     

苏云金杆菌油烟雾剂脉冲式烟雾载药技术的研究

本文首次研究了苏云金杆菌油烟雾剂脉冲式烟雾载药技术。研究结果表明,Ｂｔ菌粉柴油烟剂经过６ＨＹ－２５型烟雾机后,仍保持活力;经纯化培养Ｂｔ对家蚕毒力没有下降;Ｂｔ烟雾直接对家蚕仍有致病力。经初步筛选,Ｂｔ油烟雾剂所用油以０号柴油为较好,Ｂｔ菌粉在Ｂｉｔ柴油烟雾剂中悬浮性好,烟雾化后Ｂｔ存活力高,且能自然扩散;食用植物油次之,而１００号汽油对Ｂｔ有杀伤作用,研究还发现,烟雾机喷药咀直径大小是影响Ｂｔ存     

气溶胶间接气候效应研究进展

由于工业和人类活动的影响,大气中气溶胶含量明显增加。它们通过直接吸收和散射太阳辐射以及改变其他辐射强迫因子（云和臭氧等）的大小间接影响地－气系统的能量收支。在对大气气溶胶概述的基础上,就近年来国内外在气溶胶对气候系统的间接辐射强迫效应研究状况做了简要总结。     

A method to provide improved dose-response estimates for airborne pathogens in animals: an example using porcine reproductive and respiratory syndrome virus

This paper describes a method to provide improved probability estimates that exposure to a specific dose of an airborne infectious pathogen will result in animal infection. Individual animals were exposed to a specific dose of airborne pathogen. Following exposure, animals were individually housed and monitored for evidence of infection. The detection of specific antibodies and/or the pathogen in diagnostic specimens was evidence that the exposure dose resulted in infection. If replicated over a range of doses, the results can be used to derive a dose-response curve for a variety of animal species and infectious pathogens. This information is useful in estimating the likelihood of infection associated with exposure to airborne infectious microorganisms. Applications include predicting the risk of transmission associated with exposure to airborne pathogens, modeling the transmission of airborne pathogens, and determining requirements for effective exposure doses for vaccines delivered in aerosols.     

Validation of a dust production model from measurements performed in semi-arid agricultural areas of Spain and Niger

Models of two processes (saltation and sandblasting) that lead to fine dust release in arid areas have recently been combined to form a dust production model (DPM), the physical bases of which are summarized. In order to validate DPM at field scale, its predictions in terms of horizontal and vertical mass fluxes are compared to direct measurements made in natural conditions on a silt loam soil in north–east Spain during Wind Erosion and Loss of SOil Nutrients in semi-arid Spain (WELSONS) experiment and a sandy soil in Niger during the PROgramme Soil and Erosion (PROSE) experiment. In the Spanish case, due to the formation of a coalescing crust after rainfall, a limited supply of loose particles on the soil surface restricts the availability of soil aggregates for saltation. Once this supply limitation is taken into account in the saltation submodel, the vertical fluxes, predicted by DPM with the binding energies previously determined in a wind tunnel experiment, agree well with the measured ones. In the Niger case, the agreement is found to be directly satisfactory for unlimited saltation, even in crusted conditions. However, in order to retrieve measured vertical fluxes, the aggregate binding energies that constitute key factors involved in the sandblasting computation must be divided by 3. These results validate the sandblasting part of DPM but show that saltation has to be adequately tuned when a coalescing crust forms on loamy soils. These results also show that the potential of soil for fine-dust production does not increase with its clay content which rather tends to slightly reduce sandblasting efficiencies. A high clay content favours formation of a coalescing crust that efficiently traps formerly loose soil aggregates. The supply limitation resulting from this crust formation controls the importance of saltation, and hence, of fine-dust production. Finally, saltation clearly appears as the limiting factor for fine-dust production.