Dose Effects of Ion Beam Exposure on Deinococcus Radiodurans: Survival and Dose Response

To explore the survival and dose response of organism for different radiation sources is of great importance in the research of radiobiology. In this study, the survival-dose response of Deinococcus radiodurans (E.coli, as the control) for ultra-violet (UV), γ-rays radiation and ion beam exposure was investigated. The shoulder type of survival curves were found for both UV and γ-ray ionizing radiation, but the saddle type of survival curves were shown for H+、 N+( 20keV and 30keV) and Ar+ beam exposure. This dose effect of the survival initially decreased with the increase in dose and then increased in the high dose range and finally decreased again in the higher dose range. Our experimental results suggest that D. radiodurans, which is considerably radio-resistant to UV and x-ray and γ-ray ionizing radiation, do not resist ion beam exposure.

Effect of Short-Term Exposure to Mercuric Chloride on the Air-Breathing Catfish,Heteropneustes fossilis──Ⅱ.Scanning Electron Microscopic Study of the Gill

Alterations in the respiratory epithelium of gills of a catfish, Heteropneustes fossilis by the sublethal and lethal concentrations of HgCl2 have been observcd using scanning electron microscope. Fish exposed to 0.1 ppm shows a thin coat ot mucus, but the continuous layer of mucus is not retained in 0.3 ppm after 24 h of exposure. Epithelial cells of the gill filament are hyperplastic. Other changcs in the respiratory epithelium are contraction of epithelium, formation of interlamellar bridge and diminishing number of microridges. Massive destruction of the respiratory epithelium by deep lesions and sloughing of epithelial layer in 0.5 and 1.0 ppm solutions after 6-12 h of exposure apparently causes death to the fish. SEM observations are well in conformity with the findings made at light microscopic level

Effect of Perinatal Bisphenol A Exposure on Serum Lipids and Lipid Enzymes in Offspring Rats of Different Sex

Rats were exposed to1 or 10 μg/mL bisphenol A （BPA） in water during pregnancy and lactation. Offspring rats were given normal water and a standard diet from weaning to postnatal day （PND） 50. Perinatal exposure to BPA resulted in significantly increased body weight, visceral adipose tissue, abnormal serum lipids, and lower adiponectin （ADP） levels in both female and male offspring rats. Liver adipose triglyceride lipase （Atgl） mRNA levels and ADP protein in visceral adipose tissue were significantly decreased in BPA-exposed offspring rats. In both female or male offspring rats, obesity and dyslipidemia induced by perinatal exposure to BPA were associated with down regulation of Atgl mRNA in liver and ADP protein in visceral adipose tissue.

Effect of Short-Term Exposure to Mercuric Chloride on the Air-Breathing Catfish,Heteropneustes fossilis──Ⅰ.Light Microscopic Study of the Gill

Histopathological effects of sublethal (0.1, 0.2, 0.3 ppm) and lethal (0.5, 1.0 ppm)solutions of mercuric chloride (HgCl2) have been studied on the gills of the air breathing catfish, Heteropneustes fossilis at the intervals ranging from 6h to 15 days. Thickening of the epithelium, swelling and hyperplasia of the mucous cells, fusion of secondary lamellae, formation of interlamellar bridge and deposition of mucous over the entire surface are some noteworthy features of mercury poisoning in sublethal concentrations. Acute pathological manifestations are formation of subepithelial space, sloughing of the epithelial layer, hemorrhage and hypertrophy of the mucous cells. Causes and impact of these cellular alterations affecting survival of the fish have been discussed

Diversity and Geographical Pattern of Altitudinal Belts in the Hengduan Mountains in China

This paper analyses the diversity and spatial pattern of the altitudinal belts in the Hengduan Mountains in China. A total of 7 types of base belts and 26 types of altitudinal belts are identified in the study region. The main altitudinal belt lines, such as forest line, the upper limit of dark coniferous forest and snow line, have similar latitudinal and longitudinal spatial patterns, namely, arched quadratic curve model with latitudes and concave quadratic curve model along longitudinal direction. These patterns can be together ealled as ＂Hyperbolic-paraboloid model＂, revealing the complexity and speciality of the environment and ecology in the study region. This result further validates the hypnosis of a common quadratic model for spatial pattern of mountain altitudinal belts proposed by the authors. The spatial pattern of altitudinal belts is closely related with moisture-related exposure effect in the Hengduan Mountains. Different combinations （spectra） of altitudinal belts and different base belt types appear in windward and leeward flanks and even in the same flanks of different ranges. This is closely related with the parallel mountain ranges of the Hengduan Mountains, which, at nearly right angle with the moving direction of prevailing moisture-laden air masses from west and east, hold up the warm and humid monsoon wind from moving into the core region and result in different moisture conditions in windward and leeward flanks. However, how to quantitatively describe the moisture-related exposure effect needs further study. In addition, the data quality and data accuracy at present also affect to some extent the result of quantitative modeling and should be improved with RS/GIS in the future.

The effect of occupational exposure to coal tar pitch workers' health

Objective To investigate the effect of occupational exposure to coal tar pitch on workers’health and metabolism.Methods 805 workers exposed to coal tar pitch were selected as exposure group from the factory.Other people handle administrative and logistical affairs who not exposed to coal tar pitch were selected as control group.

Combined effects of fluoride and arsenic exposure on proliferation,differentiation and beta-catenin expression in rat osteoblasts

<正>Objective To investigate the combined effects of fluoride(Na F)and arsenate(Na As O2)exposure on proliferation,differentiation and bata-catenin expression in SD rat osteoblasts.Methods Osteoblasts were isolated from calvarias of twelve SD rats born in 1~3 days and cul-

Effect of occupational lead exposure on the blood pressure of lead-exposed workers

Objective To investigate the effect of occupational lead exposure on blood pressure and provide supportive evidence of health protection on lead-exposed workers.Methods 612 workers(452 lead-exposed workers,160workers as control)were recruited in the battery factory.The blood lead concentration and blood pressure were detected by occupational health examination and

Prediction of Perceived Air Quality for Personalized Ventilation Systems

The characteristics of the air jet from the outlet of a personalized ventilation system were related to the perceived air quality and ventilation rate. The perceived air quality was expressed as percentage of dissatisfied people for a system supplying isothermal fresh air. The relationship was verified using a thermal manikin with a breathing function in a climate chamber sitting by a desk equipped with a personalized venti- lation system. A trace gas was introduced into the climate chamber and fully mixed. The personal exposure effectiveness (εp) is based on concentrations of trace gas in the chamber and in the manikin nose which is affected more by the distance between the movable outlet and the occupant’s breathing zone than by the personalized air flowrate and does not change much for the personalized air flowrate higher than 10 L/s when the distance is fixed. Some predicted dissatisfied values for a personalized ventilation system com- pared with those acquired in human subject experiments have an absolute difference of less than 3%.