Temperature and humidity of expired air of sheep

The temperature and humidity of expired air from three adult Merino sheep were measured at air temperatures of 20, 30 and 40 degrees C before and after the animals were shorn. Expired air was apparently always saturated with water vapour. At the higher air temperatures the temperature of expired air was close to deep body temperature; at lower air temperatures, expired air had been significantly cooled, e.g. to 32.3 degrees C in shorn sheep at 20 degrees C air temperature. Expired air was cooler from shorn than from unshorn animals at 20 and 30 degrees C air temperature, possibly due to thermally induced vasomotor changes in the upper respiratory tract. Cooling of expired air would be expected to lead to recovery of some of the water evaporated during inspiration; at 20 degrees C air temperature, this fraction was estimated to be 25% in unshorn sheep and 36% in shorn sheep.     

Effect of air breathing on acid-base and ion regulation after exhaustive exercise and during low pH exposure in the bowfin, Amia calva.

To explore a potential conflict between air breathing and acid-base regulation in the bowfin (Amia calva), we examined how individuals with access to air differed from fish without air access in their response to acidosis. After exhaustive exercise, bowfin with access to air recovered significantly more slowly from the acidosis than fish without air access. While arterial blood pH (pH(a)) of fish without air access recovered to resting levels by 8 h, pH(a) was still significantly depressed in fish having access to air. In addition, Pco(2) was slightly more elevated in fish having air access than those without it. Fish with access to air still had a significant metabolic acid load after 8-h recovery, while those without air access completely cleared the load within 4 h. These results suggest that bowfin with access to air were breathing air and, consequently, were less able to excrete CO(2) and H(+) and experienced a delayed recovery. In contrast, during exposure to low pH, air breathing seemed to have a protective effect on acid-base status in bowfin. During exposure to low pH water, bowfin with access to air developed a much milder acidosis than bowfin without air access. The more severe acidosis in fish without air access was caused by an increased rate of lactic acid production. It appears that enhanced O(2) delivery allowed air-breathing bowfin to avoid acidosis-induced anaerobic metabolism and lactic acid production. In addition, during low pH exposure, plasma Na(+) and Cl(-) concentrations of fish without air access fell slightly more rapidly than those in fish with air access, indicating that the branchial ventilatory changes associated with air breathing limited, to some degree, ion losses associated with low pH exposure.     

Airflow-induced bronchoconstriction: role of epithelium and eicosanoid mediators

We examined the role of cyclooxygenase-derived metabolites and epithelial cells in airflow-induced bronchospasm. Male dogs were anesthetized and collateral system resistance (Rcs) was measured with the wedged-bronchoscope technique. A 2-min high flow challenge with dry air in nine animals produced a mean increase in Rcs of 69 +/- 13% (SE). After treatment with indomethacin (5 mg/kg), the response was significantly attenuated; Rcs increased only 40 +/- 8%. Bronchoalveolar lavage performed 5 min after a dry air challenge yielded fluid with greater concentrations of prostaglandin D2 (PGD2) and thromboxane B2 than samples from unchallenged segments. Challenge with humidified air produced a smaller physiological response than did challenge with dry air. Lavage samples obtained after dry challenge had greater concentrations of PGD2 than samples taken after challenge with humidified air. After dry air challenge, epithelial cells in lavage fluid were increased by 454 and 515% when compared with control and humidified air challenge, respectively. Significant correlations were found between epithelial cell number and PGD2 recovered in lavage fluid after dry air challenges. We conclude that both epithelial cells and prostaglandins play an important role in peripheral lung responses to dry air.     

A review of the mutagenicity and rodent carcinogenicity of ambient air

Although ambient air was first shown to be carcinogenic in 1947 and mutagenic in 1975, no overarching review of the subsequent literature has been produced. Recently, Claxton et al. [L.D. Claxton, P.P. Matthews, S.H. Warren, The genotoxicity of ambient outdoor air, a review: Salmonella mutagenicity, Mutat. Res./Rev. Mutat. Res. 567 (2004) 347-399] reviewed the literature on the mutagenicity of urban air in the Salmonella mutagenicity assay. Here, we review the literature on the mutagenicity of urban air in other test systems and review the carcinogenicity of urban air in experimental systems. Urban air was carcinogenic in most of the reports involving rodents. Studies ascribed carcinogenic activity primarily to PAHs, nitroarenes, and other aromatic compounds. Atmospheric conditions, along with the levels and types of pollutants, contributed to the variations in carcinogenic and mutagenic activity of air from different metropolitan areas. The majority of the mutagenesis literature was in the Salmonella assay (50%), with plant systems accounting for most of the rest (31%). The present data give little support to the use of plant systems to compare air mutagenicity among multiple sites or studies. Studies in mice have shown that particulate air pollution causes germ-cell mutations. Air sheds contain similar types and classes of mutagens; however, the levels of these compounds vary considerably among air sheds. Combustion emissions were associated with much of the mutagenicity and carcinogenicity of urban air. Most studies focused on the particulate fraction; thus, additional work is needed on the volatile and semi-volatile fractions, metals, and atmospheric transformation. Smaller particles have greater percentages of extractable organic material and are more mutagenic than larger particles. Although hundreds of genotoxic compounds have been identified in ambient air, only a few (<25) are routinely monitored, emphasizing the value of coupling bioassay with chemistry in the monitoring of air for carcinogenic and mutagenic activities and compounds.     

Respiratory significance of the external morphology of adults and fifth instar nymphs of Notonecta undulata Say (Aquatic Heteroptera; Notonectidae)

The bodies of adult and fifth instar Notonecta possess external air stores which are periodically renewed at the surface of the water. Both nymphs and adults have large ventral air stores on the thorax and abdomen and obtain atmospheric air at the posterior end of the latter; the adult also has dorsal subalar and supra-alar air stores on both these regions. Ten pairs of spiracles open onto the air stores. Although the seven small, ventrally placed abdominal spiracles are probably both exhalant and inhalant in nymphs and adults, the three large anterior spiracles (mesothoracic, metathoracic, and first abdominal), which play a more important respiratory role, appear to function differently in mature and immature Notonecta. In the nymph they are probably both inhalant and exhalant, and communicate broadly with each other and with the ventral air stores. In the adult, however, they open onto separate, air-filled chambers, each of which communicates differently with various parts of the air stores. Although all three probably function in exhalation, only the first abdominal spiracle, whose spiracular chamber is widely continuous with the dorsal and ventral air stores, appears to be well suited for inhalation. Several morphological features, most notably the development of long prothoracic lobes, separate spiracular chambers, and long, movable forewings, allow the adult a greater variety of respiratory modes than are available to the nymph. Some of the respiratory advantages of the adult are: (1) a larger amount of stored air; (2) a longer subalar air store, which can serve as an alternate pathway between the air stores and the atmosphere; (3) a greater capacity to utilize dissolved as well as atmospheric oxygen; (4) greater separation and functional specialization of the three anterior spiracles, thus allowing more separation of exhaled air from oxygen-rich air on the external surface of the thorax; (5) the probable ability to regulate the continuity between various parts of the air stores, thus utilizing alternate pathways of air circulation and/or changing the functions of the three anterior spiracles; and (6) better protection of the latter against the entry of water during prolonged submergence.     

城市不同植被配置类型空气负离子效应评价

通过对南宁城区、城郊绿地及农田开发区进行负离子含量的测定,找出不同植被配置类型空气负离子效应的差别。结果表明,就空气负离子而言,城郊大规模绿地的空气质量〉农田开发区〉城区;植被配置的复层结构（乔灌草）〉简单植被配置结构（乔灌、乔草、灌草）〉单一配置结构（草坪、稀乔、稀灌草）。溪流和瀑布对增加负离子浓度的作用显著。随着海拔和郁闭度的增加,空气负离子含量有上升的趋势。空气负离子含量随季节有一定的波动。     

Efficiency of Commercial Air Filters Against Marek''s Disease Virus

In a series of 10 replicate trials with susceptible chickens as indicators of the presence of virus in the air, filter B(1) (Dri Pak, American Air Filter Co.), which has a dust spot rating of 93 to 97%, and filter C (Astrocel), with a dioctyl phathalate aerosol rating of over 99%, completely removed Marek's disease virus (MDV) from highly contaminated air. However, air passed through filter B(2) (Duracel), with a dust spot rating of 34 to 45%, remained infectious. Thus, an air filter with a dust spot rating of over 93% will effectively remove MDV from the air. The smallest infectious particles in the air are estimated to be greater than 0.3 mum in diameter.     

Evaluation of a one-way airflow system in an animal room based on counts of airborne dust particles and bacteria and measurements of ammonia levels

Air cleanliness in the working area of an animal room equipped with a conventional turbulent flow air distribution systems was compared with that in a similar room fitted with a one-way-flow air distribution system; in this, the supply air flowed from the working area through the racks of cages and was removed from the exhaust side. Before the introduction of animals, the air in the working and exhaust areas of both rooms was ascertained to be Class 100. With animals in situ, however, whereas in the turbulent airflow room both the workspace and exhaust air reached about Class 10,000 (with particle counts, bacterial counts and ammonia levels being almost the same) in the one-way-flow room, the air in the work space only went up to about Class 1000. With the addition of sliding doors or curtains in front of the rack in the one-way-flow room the work space air was maintained at Class 100 with almost no dust particles over 1 microns in size, airborne bacteria or ammonia being detectable. A comparison of all factors measured showed that whereas in the turbulent flow room the contamination of the work space air was 91% of that of the exhaust air, in the one-way-flow room it was only 47%, with curtains added this was reduced to 7% and with sliding doors to only 2%. In the latter case, contamination levels increased markedly on both sides during and immediately after cage changing, but recovered to the pre-cage changing levels within 30 min in the personnel working area and within 60 min on the exhaust side.     

Efficiency of Commercial Air Filters Against Marek's Disease Virus

In a series of 10 replicate trials with susceptible chickens as indicators of the presence of virus in the air, filter B₁ (Dri Pak, American Air Filter Co.), which has a dust spot rating of 93 to 97%, and filter C (Astrocel), with a dioctyl phathalate aerosol rating of over 99%, completely removed Marek''s disease virus (MDV) from highly contaminated air. However, air passed through filter B₂ (Duracel), with a dust spot rating of 34 to 45%, remained infectious. Thus, an air filter with a dust spot rating of over 93% will effectively remove MDV from the air. The smallest infectious particles in the air are estimated to be greater than 0.3 μm in diameter.     

Fungal Colonization of Air Filters and Insulation in a Multi-Story Office Building: Production of Volatile Organics

Secondary air filters in the air-handling units on four floors of a multi-story office building with a history of fungal colonization of insulation within the air distribution system were examined for the presence of growing fungi and production of volatile organic compounds. Fungal mycelium and conidia of Cladosporium and Penicillium spp. were observed on insulation from all floors and both sides of the air filters from one floor. Lower concentrations of volatile organics were released from air filter medium colonized with fungi as compared with noncolonized filter medium. However, the volatiles from the colonized filter medium included fungal metabolites such as acetone and a carbonyl sulfide-like compound that were not released from noncolonized filter medium. The growth of fungi in air distribution systems may affect the content of volatile organics in indoor air. Received: 2 June 1997 / Accepted: 13 June 1997     

济南市南部山区不同模式庭院林空气负离子浓度

以济南市南部山区5种典型庭院林和1个无林庭院为对象,2010年3-12月对其空气负离子和相关气象因子进行同步观测.结果表明： 不同模式庭院林空气负离子浓度呈明显的季节变化,夏季>秋季>春季>冬季;其中,日变化呈双峰曲线,峰值分别出现在10:00-11:00和16:00-17:00,12:00前后出现低谷.日空气质量均在10:00和16:00最清洁,下午的空气质量优于上午;夏季空气质量最佳;园林小品型四季空气质量等级最高.不同模式庭院林年均空气负离子浓度和离子评议系数（CI）大小排序为：园林小品型>经济林果型>自然绿化型>花卉盆景型>“农家乐”型>对照.负离子浓度分别为813、745、695、688、649和570 个·cm^-3;CI为1.22、1.11、0.85、0.84、0.83和0.69.园林小品型庭院林为最理想的庭院林模式.空气负离子浓度与空气温度和相对湿度呈显著正相关,与光照强度没有相关性.     

Establishing the large scale osmotic priming of onion seeds by using enriched air

Onion seeds were primed in polyethylene glycol solutions (PEG) (-1.5 MPa) for 14 days at 15°C on filter paper and in bubble columns containing 50 g seed litre^-1 PEG using air or enriched air (75% O₂/25% N₂) to aerate and suspend the seeds. Compared with untreated seeds, priming seeds in bubble columns using enriched air increased the percentage seed germination but it did not when air was used, or when seeds were primed on filter paper. Mean germination times (t_m) were significantly reduced in all cases but the reduction was greatest using enriched air and least using air. The spread of germination times was significantly reduced only for seeds primed in enriched air. Drying seeds following priming reduced the percentage germination compared with untreated seeds, but only significantly for those primed in bubble columns using air. Drying also increased the mean germination times by 1.5 to 1.8 days (relative to primed seed which had not been dried). Seeds primed in enriched air were least affected. This increased time is that typically required for water re-imbibition after drying. Priming with enriched air followed by drying gave the same number of normal seedlings as untreated seeds.     

Effects of dry air and subsequent humidification on tracheal mucous velocity in dogs.

The impairment of mucociliary transport by dry air breathing and the restoration of function with subsequent humidification of inspired air were investigated in anesthetized dogs. Tracheal mucous velocity was measured by a cinebronchofiberscopic technique. The breathing of dry air through an uncuffed endotracheal tube produced almost complete cessation of the flow of tracheal mucus after 3 h. Subsequent breathing of air at 38 degrees C with 100% relative humidity restored tracheal mucous velocity to control values by the end of and additional 3 h. Histologic examination of the trachea at the end of the 3-h dry air breathing period revealed focal areas of sloughing of the ciliated epithelium and submucosal inflammation. Although morphometry was not employed, the inflammatory changes appeared to have progressed during 3 h of breathing fully humidified air subsequent to the dry air breathing period. These findings were consistent with previous reports that the inflammatory response to injury of the tracheobronchial mucosa might be delayed and that the mucociliary transport system has a great deal of functional reserve. We found that an artificial heat and moisture exchanger placed on the proximal end of an endotracheal tube partially protects against the suppression of tracheal mucous velocity caused by dry air breathing.     

Response of pulmonary veins to increased intracranial pressure and pulmonary air embolization

Brain compression with subdural air causes pulmonary hypertension and noncardiogenic pulmonary edema (A. B. Malik, J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 42: 335-343, 1977). To see whether air emboli to the lungs rather than brain compression caused these findings, anesthetized dogs received intravenous air infusions, subdural air infusions, or brain compression from balloons inflated in the subdural space. Subdural air and intravenous air resulted in similar vascular responses. Pulmonary artery pressure (Ppa) increased 160% (P less than 0.01) and pulmonary venous pressure transiently rose 13 +/- 5 Torr (P less than 0.05) without an increase in left atrial pressure or cardiac output (Q). The end-tidal PCO2 fell 55% (P less than 0.01) and the postmortem weight of the lungs increased 55% (P less than 0.05). Brain compression with a subdural balloon instead of air only caused a 20% rise in Ppa and Q without pulmonary edema. Thus, pulmonary air emboli rather than brain compression accounts for the edema and pulmonary hypertension caused by subdural air. Catheters in pulmonary veins and the left atrium showed that air emboli cause transient pulmonary venous hypertension as well as a reproducible form of noncardiogenic pulmonary endema.     

空气负离子浓度分布的影响因素研究综述

近年来随着生态旅游的日益兴起,空气负离子作为一种生态保健旅游资源越来越受到人们的关注。研究空气负离子浓度分布规律可以指导人们在合适的地点、合适的时间充分利用自然状态下产生的空气负离子调养身心。通过查阅国内近十多年有关空气负离子的文献资料,对空气负离子浓度分布规律及其影响因素的有关研究进展进行了综述。现有的研究表明,空气负离子浓度变化及其分布主要受到气象、时空、植物和水体等因素的影响。今后,应加强空气负离子的产生机制及其生态学效应等方面的研究,以便更好地为空气负离子资源的合理开发和生态环境保护提供理论依据。     

固态发酵的参数周期变化及对微生物发酵的影响

研究了压力脉动固态发酵反应器内环境参数的周期性变化以及这些周期性的环境刺激对于固态培养的斜卧青霉发酵的影响。研究结果显示:在这种反应器中,在空气压力脉动的带动下,反应器内的温度和空气湿度也会发生较大幅度的周期性变化,变化的周期和空气压力脉动的周期相同,变化的幅度随着压力脉动的幅度增大而增加;在外界周期刺激的条件下,较未加外界周期刺激斜卧青霉的生物量增加了104% ,二氧化碳的产生总量增加了229%和纤维素酶的产量增加了320 % ,数据显示外界周期刺激不仅增加了菌体的生物量同时增加了其代谢活性。     

Effect of body orientation on regional lung expansion: a computed tomographic approach

The Dynamic Spatial Reconstructor (DSR) was used to study in vivo lung geometry and function. By replacing the lungs of three dogs with potato flakes and ping-pong balls of known air content and scanning these realistic phantoms in the DSR we have estimated accuracy of lung density to be within 7% and have demonstrated a high (+/- 3%) internal consistency (relative density within dogs). Change in total lung air content (y) as calculated from DSR volume imaging of anesthetized dogs matched the known inflation steps (x) to within 7% [range was 1-7% with a mean of 3 +/- 0.5% (SE)]. A gradient of decreasing percent lung air content was measured in the ventral-dorsal direction at functional residual capacity (FRC) in the supine body posture (y = 3.29% air content/cm lung height + 46.48% air content; r = 0.90). Regional lung air content change with lung inflation was greatest in the dependent lung regions. In contrast, regional lung air content at FRC was approximately uniform along the ventral-dorsal direction with the dog in the prone posture and was 66 +/- 0.6% (SE). Ventral-dorsal gradients in lung air content measured within an isogravimetric plane of the dogs in the left or right lateral body posture suggest that regional differences in lung air content cannot be explained solely on the basis of a direct gravitational effect on the lung. Evidence is presented to suggest a possible major role of the intrathoracic position of the mediastinal contents in determining these lung air content distributions.     

Ultra-low luminescence of humid air and its possible role in negative air ion therapy

One of the unresolved questions related to the mechanism of action of light negative air ions (reactive oxygen species) produced by air ionizers upon humans and animals is transmission of these short-living chemical species upon long distances from the place of their origin. We discovered the phenomenon which may probably resolve this problem. When a thin layer of water hydrating a hygroscopic surface absorbs rare UV-photons capable to split water molecules a flash of photon emission in UV- and visible regions of spectrum is observed. This flash (or oxygen-dependent oxidative processes underlying it) initiate reactions accompanied with generation of electronic excitation in the air contacting water film. Excitation propagates through the air at macroscopic distances, and the level of propagating excitation increases with elevation of air humidity. When air humidity exceeds 50% air excitation gains oscillatory-wave character. This phenomenon may endow into the mechanism of action of air ions generated artificially, and also into some natural processes where ordered water films may form and the latter may serve targets for energy impulses initiating oxygen-dependent oxidative processes in these films.     

The Influence of Ward Ventilation on Hospital Cross Infection

S ummary : A ventilation system combining fresh air intake with recirculation of ward air, through an electrostatic air filter, was introduced into a ward in which it had been shown that poor ventilation was a major factor in its high cross infection rate. A considerable reduction in bacterial air contamination and in the cross infection rate in that ward was achieved.     

Method of isolating pathogenic enterobacteria from atmospheric air]

The authors present comparative results of determination of sedimentation and aspiration methods of air pollution by pathogenic enterobacteria during the artificial sewage "raining". Results (in per cent) of isolation of salmonellae from the air by both methods proved to be very close; however, a possibility of isolation of pathogenic bacteria from the air increased with the use of the apparatus for the examination of large air volumes.