Mutagenic properties of PM2.5 air pollution in the Padana Plain (Italy) before and in the course of XX Winter Olympic Games of "Torino 2006"

PM2.5 is one of the most important aspects of environmental health. This air pollutant is breathable and it is implicated in several chronic adverse health effects such as the decrease of respiratory functionality and cancer. Several in vitro bioassays are able to predict the mutagenic/carcinogenic activity of the environmental pollutants and mixtures of them. In this study PM2.5 air pollution was daily monitored in three cities located in the Northern part of Italy and the mutagenic properties of the PM2.5 organic extracts were also assessed. Samplings lasted 14 months and cover the period of the Winter Olympic Games of "Torino 2006". In this work, the levels of PM2.5, its mutagenic properties (detected with Salmonella typhimurium assay), the role of the Olympic Games as environmental factor and some meteorological data are discussed. The mean concentration of PM2.5 measured in Torino was 45.4 (+/-30.6) microg/m(3), in Pavia 37.6 (+/-25.6) microg/m(3), in Verona 43.1 (+/-28.5) microg/m(3). Findings of the monthly pool bioassay were in Torino 107 (+/-104) net revertans/m(3), in Pavia 108 (+/-89) net revertans/m(3), in Verona 128 (+/-109) net revertans/m(3). The Olympic Games period data show that PM2.5 pollution and its load of mutagenic potential are different and partially independent phenomena. The Olympic Games had not a great impact on the PM2.5 pollution. The exclusive PM2.5 gravimetric analysis shows a potential human risk if compared with the latest international guide values but it does not describe exhaustively the human health risk associated to the presence of this particular air pollutant. Moreover, the chemical and biological activity qualification of the PM organic extracts as a whole, can instead improve the knowledge.     

Land change in the southern Yucatán and Calakmul biosphere reserve: effects on habitat and biodiversity.

The southern Yucatán contains the largest expanse of seasonal tropical forests remaining in Mexico, forming an ecocline between the drier north of the peninsula and the humid Petén, Guatemala. The Calakmul Biosphere Reserve resides in the center of this region as part of the Mesoamerican Biological Corridor. The reserve's functions are examined in regard to land changes throughout the region, generated over the last 40 years by increasing settlement and the expansion and intensification of agriculture. These changes are documented from 1987/1988 to 2000, and their implications regarding the capacity of the reserve to protect the ecocline, forest habitats, and butterfly diversity are addressed. The results indicate that the current landscape matrix serves the biotic diversity of the reserve, with several looming caveats involving the loss of humid forests and the interruption of biota flow across the ecocline, and the amount and proximity of older forest patches beyond the reserve. The highly dynamic land cover changes underway in this economic frontier warrant an adaptive management approach that monitors the major changes underway in mature forest types, while the paucity of systematic ecological and environment-development studies is rectified in order to inform policy and practice.     

Levels of cadmium and zinc in soil and plants following the toxic spill from a pyrite mine,Aznalcollar, Spain

On 25 April 1998, a breach of the tailings dam of the Los Frailes pyrite mine in southwestern Spain resulted in the release of 6 million m3 of acidic water and toxic sludge high in heavy metals. Contaminated material extended 40 km downstream, affecting agricultural land and parts of the wildlife-rich Do?ana Natural and National Parks, including the Entremuros, a very important area for birds. We report on the concentrations, distributions and bioavailability of zinc and cadmium in soil and vegetation from the Entremuros in November 1998 and October 1999, following 2 'cleanup' operations. Levels of Zn and Cd in soil increased significantly over this period, although this was not reflected consistently in metal concentrations in emergent macrophytes. We recommend monitoring of further cleanup attempts in order to develop means of minimizing potential impacts to wildlife in the area.     

Increased levels of bacterial markers and CO2 in occupied school rooms

Our group previously demonstrated that carbon dioxide (CO2) levels in heavily occupied schools correlate with the levels of airborne bacterial markers. Since CO2 is derived from the room occupants, it was hypothesized that in schools, bacterial markers may be primarily increased in indoor air because of the presence of children; directly from skin microflora or indirectly, by stirring up dust from carpets and other sources. The purpose of this project was to test the hypothesis. Muramic acid (Mur) is found in almost all bacteria whereas 3-hydroxy fatty acids (3-OH FAs) are found only in Gram-negative bacteria. Thus Mur and 3-OH FA serve as markers to assess bacterial levels in indoor air (pmol m(-3)). In our previous school studies, airborne dust was collected only from occupied rooms. However, in the present study, additional dust samples were collected from the same rooms each weekend when unoccupied. Samples were also collected from outside air. The levels of dust, Mur and C10:0, C12:0, C14:0, and C16:0 3-OH FAs were each much higher (range 5-50 fold) in occupied rooms than in unoccupied school rooms. Levels in outdoor air were much lower than that of indoor air from occupied classrooms and higher than the levels in the same rooms when unoccupied. The mean CO2 concentrations were around 420 parts per million (ppm) in unoccupied rooms and outside air; and they ranged from 1017 to 1736 ppm in occupied rooms, regularly exceeding 800-1000 ppm, which are the maximum levels indicative of adequate indoor ventilation. This indicates that the children were responsible for the increased levels of bacterial markers. However, the concentration of Mur in dust was also 6 fold higher in occupied rooms (115.5 versus 18.2 pmole mg(-1)). This further suggests that airborne dust present in occupied and unoccupied rooms is quite distinct. In conclusion in unoccupied rooms, the dust was of environmental origin but the children were the primary source in occupied rooms.     

Rapid measurement of indoor mass-transfer coefficients

Indoor air pollutant concentrations can be influenced by how rapidly species are transported to and from surfaces. Consequently, a greater understanding of indoor transport phenomena to surfaces improves estimates of human exposure to indoor air pollutants. Here, we introduce two methods of rapidly and directly measuring species fluxes at indoor surfaces, allowing us to evaluate the transport-limited deposition velocity, v_t (a mass-transfer coefficient). The deposition velocity sensor (DeVS) method employs a small microbalance coated with a pure hydrocarbon, preferably octadecane. We quantify flux (or evaporation rate) of the hydrocarbon into a room by observing the rate of mass loss on the microbalance. The transport-limited deposition velocity, v_t,octadecane, is then obtained by combining the flux with the vapor pressure of the hydrocarbon. Simultaneously, v_t,ozone is quantified using the deposition velocity of ozone (DeVO) method, which acts as a standard to calibrate and evaluate DeVS. Specifically, DeVO evaluates ozone transport to surfaces by quantifying the conversion by ozone of nitrite to nitrate on a glass fiber filter. Simultaneous laboratory chamber experiments demonstrates that v_t for octadecane and ozone are strongly correlated, with the values for ozone 1.5 times greater than that for octadecane. In an office experiments, the DeVS method responds within minutes to step changes in conditions such as occupancy, activities and ventilation. At present, the results are in order-of-magnitude agreement with predicted indoor mass-transfer coefficients.     

绿色科技助力西部少数民族脱贫

UNDP通过了一个为期4年的联合国西部扶贫项目，生活在四川、贵州和云南三省交界地区的农户将可以用当地的一种特殊树种麻风树来生产生物燃料，以提高能源供应。由联合国开发计划署、中国科技部和商务部中国国际经济技术交流中心共同发起的这一项目。总预算为858．5万美元，旨在通过绿色技术来帮助中国西部地区减少贫困。并改善那里脆弱的生态系统。“中国绿色扶贫”项目的目的是帮助他们开发新的能源物质，并在项目所在地区发展绿色能源。     

Congenital cystic hygroma of the neck diagnosed prenatally: Outcome with normal and abnormal karyotype

Twenty-two cases of cystic hygromas were diagnosed prenatally at Eastern Virginia Medical School and followed through the neonatal period. Our series was combined with 131 cases which have been described in the literature. Karyotypes were obtained in 110 fetuses and 80 (72·7 per cent) were abnormal. Fifty-one were not terminated: 30 with abnormal and 21 with normal karyotypes. There were no neonatal survivors in the group with abnormal karyotypes. There were five survivors in the 21 with normal karyotypes but only 2/21 without severe medical complications. Combining our series with those previously reported in the literature would suggest only a 2–3 per cent rate of intact survivors when fetal cystic hygromas are diagnosed in utero. This information should be helpful when counselling patients whose pregnancies carry this diagnosis.     

Bioaccumulation of toxic hydrophobic organic compounds at the primary trophic level

The prevailing hypothesis, which states that the uptake of HOCs by phytoplankton is controlled by the compound's lipophilicity (Kow) was tested. The approach taken was to determine the factors that controlled the uptake of PCBs by phytoplankton under controlled laboratory conditions, and to develop a model that would describe bioaccumulation of PCBs in phytoplankton.The results demonstrate a relationship of BAF to Kow and to phytoplankton surface properties, as well as the data presented here, support the hypothesis that the mechanism of HOC uptake is a rapid surface sorption followed by a slower transfer into lipids in the cell matrix. The work on the kinetics of uptake indicates that equilibrium is reached slowly and that the rate of uptake is of similar magnitude as phytoplankton growth under normal field conditions.Thus a critical factor that controls the bioaccumulation of HOCs reach equilibrium in phytoplankton itself.     

视频存储策略

在常用的视频监控系统中,DVR是一个极为重要的部件,但是其应用绝不仅仅限于提供实时或者回放图像这样简单的工作。如果将DVR与门禁系统、入侵探测系统、报警控制面板、ATM机等连接起来的话,就可以为终端用户提供更加广泛的解决方案,包括便利店防盗、销售点监控等等。 既然DVR如此重要,那么如何正确使用其存储功能呢?在实际应用过程中,图像文件的大小、帧率、传输方式以及带宽等因素都对数据存储有一定的影响。如果对整体的存储没     

Determination of technetium-99 using electrothermal vaporization inductively coupled plasma-mass spectrometry (ETV-ICP-MS) and NH4OH as chemical modifier

In recent years, developments in ICP-MS have led to improved methods for determination of long-lived radionuclides. This paper reports the use of NH(4)OH as a matrix modifier and ETV sample introduction for the determination of technetium-99 ((99)Tc) in a variety of environmental and biological samples, using Re as carrier and (99m)Tc as yield monitor in the chemical separation method. Addition of an excess of NH(4)OH led to a stable (99)Tc signal, reduced memory effect, better reproducibility and reduced detection limits. Following radiochemical separation of (99)Tc from the sample matrix, detection limits in the order of a few microBq have been achieved. ETV has also proved applicable for rapid, direct analysis of a number of environmental samples having relatively high concentrations of (99)Tc (sediment extracts and river water close to nuclear installations). However, in this case, control of matrix effects (signal reduction and enhancement) using standard additions is necessary.