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At least 1,063 records · Page 59Linked to original sources

PubMed2001

[Effect of elevated atmospheric CO2 concentration on Rhopalsiphum padi population under different soil water levels].

With the aim of forecasting the wheat-aphid relationships under different precipitation in the future atmospheric CO2 environment, the effects of different atmospheric CO2 concentration on Rhopalsiphum padi population under different soil water levels in Open-Top chambers were studied. The results showed that Rhopalsiphum padi population grew constantly with the continuous rising of atmospheric CO2 and it grew more quickly when CO2 concentration increased from 350 microliters.L-1 to 550 microliters.L-1. In each CO2 concentration treatment, R. padi population were distinct under different soil water level, and they were the highest under 60% of field water capacity treatment. When CO2 concentration increased from 350 microliters.L-1 to 550 microliters.L-1, the increase of R. padi population under 60% of field water capacity treatment was higher than that under 40% and 80% treatment. When CO2 concentration increased from 550 microliters.L-1 to 700 microliters.L-1, the increases of R. padi population under 60% and 40% soil water treatments were the same and both higher than that under 80% treatment. These results suggested that R. padi population would grow more quickly from the beginning to the middle of the 21st century and bring more damages to the wheat in arid and semiarid area.

Animals↗

PubMed1998

Proposed minimum requirements for the operational characteristics and testing of submersible atmosphere monitoring and control units.

The design of a submersible and its myriad subsystems is a complex undertaking made more difficult by the interval between new designs. Special applications also tax the life support designer, such as diver lock-out submersibles, which are far more complex than one-atmosphere vehicles. The long intervals between designs generally means that a new generation of designers will be approaching the problems without the benefit of the knowledge and experience of the past generation of designers. This new generation of designers often has greatly improved technologies and materials at hand. Yet in the application of the new technology, life support issues that were addressed and resolved in the old and proven designs get lost in the process of redesign due to the lack of experience in the life support arena. Competent engineers operating outside their normal area of expertise can generate costly or even deadly mistakes. For this reason a set of performance requirements that details the critical functions of the life support systems is needed. Atmosphere control electronics can seriously impact the safety of the submersible crew. The triple dangers of fire, toxicity, and asphyxia demand that the electronics that monitor and control the submarine compartment atmosphere have certain characteristics. These characteristics are easily captured in a performance requirement. This article will present a set of proposed minimum performance requirements, with the goal of establishing a dialog for the creation of guidelines for the classification, rating, design, and testing of embedded electronics for life support systems used in submersible applications. These guidelines will serve as the foundation for the later creation of a set of industry specifications.

Air Conditioning↗

PubMed2002

[Determination of volatile hydrocarbon in atmosphere by two-dimensional capillary column gas chromatography].

Fifty-seven volatile hydrocarbons (VHCs) (C3-C10) in the atmosphere have been determined by two-dimensional capillary column gas chromatography. The samples were preconcentrated using adsorption/two stages of thermal desorption. The samples were analysed by dual columns (PLOT, 50 m x 0.32 mm i.d. x 8 microns, Al2O3/Na2SO4; HP-1, 50 m x 0.22 mm i.d. x 0.5 micron, methyl silicone)/dual flame ionization detectors(FID). The qualitative stability of the method is good. The relative standard deviation of the peak area response is smaller than 20%. The correlation coefficients(r2) for linear regression equations for PLOT and HP-1 columns were 0.9990 and 0.9997 respectively. Analytical period was 48 min. The 182 atmospheric samples from the Ecological Station of Changshu, Jiangsu were measured. The results show that the method is accurate, rapid and practically useful for the determination of the VHCs in atmosphere.

Adsorption↗

PubMed2003

CO2 deficit in temperate forest soils receiving high atmospheric N-deposition.

Evidence is provided for an internal CO2 sink in forest soils, that may have a potential impact on the global CO2-budget. Lowered CO2 fraction in the soil atmosphere, and thus lowered CO2 release to the aboveground atmosphere, is indicated in high N-deposition areas. Also at forest edges, especially of spruce forest, where additional N-deposition has occurred, the soil CO2 is lowered, and the gradient increases into the closed forest. Over the last three decades the capacity of the forest soil to maintain the internal sink process has been limited to a cumulative supply of approximately 1000 and 1500 kg N ha(-1). Beyond this limit the internal soil CO2 sink becomes an additional CO2 source, together with nitrogen leaching. This stage of "nitrogen saturation" is still uncommon in closed forests in southern Scandinavia, however, it occurs in exposed forest edges which receive high atmospheric N-deposition. The soil CO2 gradient, which originally increases from the edge towards the closed forest, becomes reversed.

Carbon Dioxide↗

PubMedDate not supplied

[Evaluation of antimicrobial drugs and atmospheres for the isolation of Campylobacter fetus subspp. from the bovine genital tract].

Growth of 3 reference bovine C. fetus strains in media with and without antibiotics and bacteriostats active against the most common contaminant bacteria in the bovine genital tract was evaluated. In addition, 2 regional bovine C. fetus strains and 1 reference C. sputorum biovar bubulus strain were used in some experiments. Reference strain C. fetus subsp. venerealis was completely inhibited by polymyxin (> or = 0.25 IU/ml) whereas the other C. fetus strains were not inhibited. In Shepler's medium supplemented with rifampicin (10 micrograms/ml) subsp. fetus, was the only one to grow. When rifampicin was used at 5 micrograms/ml together with a reduced dose of the other Shepler's antibiotics, especially polymyxin B (0.85 IU/ml), subsp. venerealis was able to grow; nevertheless even at such a reduced dose, rifampicin was inhibitory for the biotype intermedius. It was demonstrated that triclosan (Irgasan) could be very useful at < or = 10 micrograms/ml in media with added blood, < or = 6 micrograms/ml in brucella broth and < or = 3 micrograms/ml in Mueller-Hinton broth for isolation of all subspecies of C. fetus. The sensitivity of C. fetus to 5-fluorouracil was variable: subsp. fetus was resistant (up to 800 micrograms/ml) whereas subspp. venerealis and biotype intermedius grew slowly or sometimes did not grow at all in concentrations of 6.25 micrograms/ml onwards. Fosfomycin was inhibitory to all C. fetus strains at > or = 50 micrograms/ml. C. sputorum biovar. bubulus was less inhibited than C. fetus with triclosan grew up to more than 100 micrograms/ml, with 5-fluorouracil up to 100 micrograms/ml and with fosfomycin up to 50 micrograms/ml. Growth of C. fetus subspp. was compared in different microaerophilic atmospheres contained in anaerobic jars (Oxoid HP 11) without palladium catalyzer. Growth with nitrogen or hydrogen was similar. When jars were replaced by 15 x 13 cm cylindrical cans without valves or gas measurement devices only pure hydrogen supported satisfactory growth of all C. fetus subspp. and C. sputorum biovar. bubulus strains. The candle system, a commercial nitrogen rich gas mixture and pure carbonic anhydride prepared in these cans failed to enable these strains to grow. C. fetus subsp. fetus was more aero-tolerant than subsp. venerealis and its biotype intermedius and was able to grow, although very weakly, with only carbonic anhydride added to an aerobic atmosphere. The growth obtained using a commercial gas generating microaerophilic kit (Oxoid BR-56) was comparable to the one achieved with the hydrogen rich atmosphere prepared in our laboratory.

Agar↗

PubMed1992

[Lung cancer among the autochthonous population and among immigrants Upper Silesia in relation to smoking, exposure to harmful factors at work and atmospheric pollution].

By the case-control method 367 patients with lung carcinoma coming from the autochthonous population of Upper Silesia and 253 similar patients from the population of immigrants from other areas were compared (620 cases, in all) treated in the Institute of Oncology in Gliwice in the years 1982-1989. They accounted for about 85% of all male patients with this tumour. In the analysis three zones of Upper Silesia with varying concentrations of atmospheric pollution, where the patients lived, were considered, estimating the risk of this tumour in relation to pollution level, and standardizing the risk for tobacco smoking and considering data related to the exposure to harmful factors in occupational work. The analysis showed that the so called summarized index of relative risk was about 2.5 times greater for the autochthonous as well as immigrant populations in the zone of greatest atmospheric pollution with statistically significant differences in relation to the relatively most favourable zone (accepted as 1.00) However, the risk was progressively rising only in the autochthonous population (in all 3 zones). That showed that the risk of lung carcinoma was increasing in this population with increasing atmospheric pollution. This evident progression of risk was not found in the population of immigrants, although the risk level in this population living in the zone of greatest pollution was similar to that in the autochthonous population.

Adult↗

PubMed2004

[Dimethylsulfide emission in Qingdao near-shore waters and atmospheric dimethylsulfide concentration variation].

To investigate the emission of dimethylsulfide in near-shore waters seriously disturbed by human activities in China, using the solid absorption-desorption and cryogenic preconcentration method, sampling and analysis of seawater and atmospheric DMS in Qingdao near-shore waters were carried out during 2001-2002. The results showed that the spatial distribution and seasonal variation of seawater DMS concentrations and sea-air fluxes were evident. In summer, the average of seawater DMS concentrations was highest, amounting to 1169.47 ng x L(-1) and lowest in spring, only 226.99 ng x L(-1). The obvious concentration gradient in estuarine, landscape and Olympic Game areas were observed in summer, but in spring and autumn is not so evident. Sea-air flux of DMS was mainly determined by seawater concentration, therefore the sea-air flux coincided with seawater concentration. Average atmospheric DMS concentration was higher in the summer (256.44 ng x m(-3)) and lower in the autumn (195.64 ng x m(-3)). The diurnal variation of atmospheric DMS was discussed in paper.

Air Pollutants↗

PubMed2004

Highly sensitive screening method for nitroaromatic, nitramine and nitrate ester explosives by high performance liquid chromatography-atmospheric pressure ionization-mass spectrometry (HPLC-API-MS) in forensic applications.

A highly sensitive screening method based on high performance liquid chromatography atmospheric pressure ionization mass spectrometry (HPLC-API-MS) has been developed for the analysis of 21 nitroaromatic, nitramine and nitrate ester explosives, which include the explosives most commonly encountered in forensic science. Two atmospheric pressure ionization (API) methods, atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI), and various experimental conditions have been applied to allow for the detection of all 21 explosive compounds. The limit of detection (LOD) in the full-scan mode has been found to be 0.012-1.2 ng on column for the screening of most explosives investigated. For nitrobenzene, an LOD of 10 ng was found with the APCI method in the negative mode. Although the detection of nitrobenzene, 2-, 3-, and 4-nitrotoluene is hindered by the difficult ionization of these compounds, we have found that by forming an adduct with glycine, LOD values in the range of 3-16 ng on column can be achieved. Compared with previous screening methods with thermospray ionization, the API method has distinct advantages, including simplicity and stability of the method applied, an extended screening range and a low detection limit for the explosives studied.

Journal Article↗

PubMed2004

[Effects of low oxygen-modified atmosphere packaging on browning and lignification of peeled bamboo shoots].

The browning and lignification of peeled bamboo shoots (Phyllostachys praecox f. prevelnalis) under modified atmosphere packaging (MAP) with a combination of 2% O(2)+5% CO(2)+93% N(2) in 0.04 mm polyethylene bag during storage at 10 degrees C were investigated. The results indicated malondialdehyde (MDA) content of bamboo shoots under MAP with low O(2) atmosphere was lower than that in the control during early storage, the activities of peroxidase (POD) and phenylalanine ammonia-lyse (PAL) were significantly inhibited (P<0.05 and P<0.01, respectively), and the browning of bamboo shoots under MAP with low O2 atmosphere was eventually significantly prevented (P<0.01) and cellulose and lignin contents were significantly decreased (P<0.05). The browning of bamboo shoots was probably caused by POD and PAL activities, and the increase in POD and PAL activities might account for the lignification of bamboo shoots.

Bambusa↗

PubMed2005

Study on the total amount control of atmospheric pollutant based on GIS.

OBJECTIVE: To provide effective environmental management for total amount control of atmospheric pollutants. METHODS: An atmospheric diffusion model of sulfur dioxide on the surface of the earth was established and tested in Shantou of Guangdong Province on the basis of an overall assessment of regional natural environment, social economic state of development, pollution sources and atmospheric environmental quality. Compared with actual monitoring results in a studied region, simulation values fell within the range of two times of error and were evenly distributed in the two sides of the monitored values. Predicted with the largest emission model method, the largest emission of sulfur dioxide would be 54,279.792 tons per year in 2010. CONCLUSION: The mathematical model established and revised on the basis of GIS is more rational and suitable for the regional characteristics of total amount control of air pollutants.

Air Pollutants↗

PubMed2005

[Prediction of atmospheric Japanese cedar pollen counts in Oita University Faculty of Medicine Complex].

BACKGROUND: We investigated the method of predicting atmospheric Japanese cedar pollen counts and the first day of pollen release at Oita University Faculty of Medicine Complex in this study. METHOD: We set up a Durham sampler on the roof (30 m from the ground) of Oita University Faculty of Medicine complex and investigated atmospheric pollen counts day by day from January 1 to April 30 from 1990 through 2004. RESULTS: The total pollen counts per year correlated very well with averaged temperature, averaged relative humidity, and the sunshine duration during the previous July. The sunshine duration yielded the highest correlation coefficient. Multiple regression analysis showed the sunshine duration during the previous July and total pollen count of the previous year to be independent predictors of the current year's total pollen counts. Multiple correlation coefficients was 0.9518 (p<0.001). We considered the Hita area to be the source of the pollen, according to meteorological conditions. Prediction of total pollen counts was more accurate if based on factors within the previous 10 years than on factors within the previous 5 years. There was no correlation between the first day of pollen release and averaged temperature in January. Our data also showed that the first day of pollen release could not be predicted by the cumulative thermal constant method and threshold temperature for the development of male Japanese cedar flowers. Multiple regression analysis showed the minimum temperature from November 1 to the first day of pollen release, the date of minimum temperature, and the averaged temperature for the January to be independent predictors of the number of days from January 1 to the first day of pollen release. CONCLUSION: We concluded that it is important to establish a method of predicting atmospheric Japanese cedar pollen counts that is based on the characteristics of each area.

Cryptomeria↗

PubMedDate not supplied

Light emission requires exposure to the atmosphere in ex vivo bioluminescence imaging.

The identification of organs bearing luciferase activity by in vivo bioluminescence imaging (BLI) is often difficult, and ex vivo imaging of excised organs plays a complementary role. This study investigated the importance of exposure to the atmosphere in ex vivo BLI. Mice were inoculated with murine pro-B cell line Ba/F3 transduced with firefly luciferase and p190 BCR-ABL. They were killed following in vivo BLI, and whole-body imaging was done after death and then after intraperitoneal air injection. In addition, the right knee was exposed and imaged before and after the adjacent bones were cut. Extensive light signals were seen on in vivo imaging. The luminescence disappeared after the animal was killed, and air injection restored the light emission from the abdomen only, suggesting a critical role of atmospheric oxygen in luminescence after death. Although no substantial light signal at the right knee was seen before bone cutting, light emission was evident after cutting. In conclusion, in ex vivo BLI, light emission requires exposure to the atmosphere. Bone destruction is required to demonstrate luciferase activity in the bone marrow after death.

Air↗

PubMed2006

[The study of infrared background radiation of earth and atmosphere by airborne FTIR spectrometer].

The present article describes the experiment of airborne Fourier transform infrared (FTIR) spectrometer detecting the background radiation of earth and atmosphere. Considering the surface radiation and atmospheric absorbance and emission, the expression of radiations measured by airborne FTIR is given. It is indicated that the background radiations depend on four parameters: surface temperature, surface emissivity, atmospheric transmission and temperature. Based on theoretic analysis the measured spectra are compared and analyzed according to the differences in altitude and surface. Spectral characters of infrared background radiation are described.

English Abstract↗

PubMed2006

[Measurement of NO2 concentration in atmosphere in Chengdu by solar spectra].

In the present paper, a new improved method for measuring NO2 concentration of atmosphere by using differential optical absorption spectroscopy of solar spectrum was reported. The sample solar spectra were collected in Chengdu city and Xiling Mountain respectively by a CCD optical multi-channel analyzer. With the upper atmosphere solar spectrum as the reference spectrum, by fitting the sample spectrum and the reference spectrum using least-square method in five spectrum ranges, the various NO2 concentrations (vertical column density) of 3.1 x 10(16) to 5.8 x 10(16) (molecule x cm(-2)) in Chengdu city and 0.7 x 10(16) to 1.0 x 10(16) (molecule x cm(-2)) in Xiling Mountain were obtained respectively. The NO2 concentrations of atmosphere showed an increasing tendency with the rising temperature.

English Abstract↗

PubMed2006

[Stable carbon isotope analysis method for the atmospheric formaldehyde].

A method of compound-specific stable carbon isotopic analysis for the research about the sources of atmospheric formaldehyde was preliminary studied using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) via 2, 4-dinitrophenylhydrazine (DNPH) derivatization. In order to evaluate the reproducibility, the accuracy and the carbon isotope effects of the method, formaldehyde with different delta 13C values were used to simulate the sampling procedure. The results show that the maximal analytical deviation for all formaldehyde 2, 4-dinitrophenylhydrazone is 0.3 per thousand and the average deviations between the determined and theoretical delta 13C values of them are 0.24 per thousand +/- 0.14per thousand (ranged from 0.03 per thousand to 0.35 per thousand), less than 0.5 per thousand the technical specifications of the GC/C/IRMS system. These mean that no carbon isotopic fractionation occurred during the procedure. The study for the indoor and outdoor atmospheric formaldehyde in the restaurant show that the stable carbon isotopic compositions are significant different for different sources of formaldehyde. The present method could provide valuable information about the sources of atmospheric formaldehyde.

Air Pollutants↗

PubMed1991

[The health problems related to atmospheric pollution in large industrial regions of Bulgaria].

Epidemiological studies are performed in some towns and large industrial regions of the country, in order to establish the changes in the health state of the population, due to atmospheric pollutants. The attention is directed to regions with national industrial branches, most intensively polluting the atmospheric air (metallurgy, chemistry, petroleum-chemistry, cellulose-paper industry) and such, where the air pollution is related first of all to transport across the border-line. The unfavourable effect of the atmospheric pollution on the exposed population is proved. It is however, the reason for increased morbidity according to a number of nozologics and on first place--of respiratory and allergic diseases. Parallel to that are interpreted the results of the performed inquiries and paraclinical studies, revealing the presence of prior to the disease changes in the population of the examined regions.

Air Pollution↗

PubMed1991

Incidence of atmospheric pollen in the Pretoria-Witwatersrand-Vereeniging region during 1987/1988.

Atmospheric pollen and spores have been monitored continuously in the Pretoria-Witwatersrand-Vereeniging region (PWV) since 1987. Two Burkard 7-day recording traps were used in Johannesburg and Pretoria, and 11 gravity samplers were installed at various sites in the PWV. An analysis of the pollen component and pollen calendars average data for 1987 and 1988 are presented. Grass pollen was the most significant contributor in absolute and relative terms, comprising 52% of total pollen. The season peaked between October and March, but grass pollen was found throughout the year. Pollen of Northern Hemisphere trees was abundant, relative to that of indigenous trees. The flowering season for these exotics was very short and intense, possibly due to the short spring season. Seasonal taxa started flowering earlier in Pretoria than in Johannesburg. Herbaceous taxa were well represented in the atmospheric sample. The major contributor was the daisy family. The greatest proportion of pollen, 58.8%, was non-seasonal. Species in this category flower consecutively throughout the year. Of the taxa, 28.4% were spring-flowering. The allergenicity of pollen encountered in the atmospheric sample is discussed.

Air Pollutants↗

PubMed1990

Immunoglobulins and some serum proteins in children with altered resistance coming from areas with variously polluted atmosphere.

In four areas with different types of atmospheric pollution 534 children of school age were examined for serum immunoglobulins (IgG, IgA, IgM and IgE), saliva IgA (sIgA), lysozymes (LYS) and acute phase reactants (alfa-l-antitrypsin - A1AT, alfa-2-macroglobulin -A2M, ceruloplasmin -CPL, transferrin - TRF). The children were divided into two groups: those with altered resistance (AR) comprising allergoses of all types and recurrent or persistent infections and those without the above health problems, i.e. healthy (H). There were more children with AR in areas with higher atmospheric pollution than in control areas. The frequency of AR was higher among boys than among girls. In the control area BN, a number of parameters in the AR group differed significantly from those in the H group. In areas with substantial atmospheric pollution these differences were generally less pronounced. Significant differences were found between the control and polluted areas in many indicators. In the area KO characterized by an intermediate degree of industrial pollution the means of the tested parameters were habitually elevated, whereas in the heavily polluted areas they were decreased. The most sensitive tests for evaluating differences between the areas were the levels of A1AT, LYS, and IgE, while the variations of sIgA, sLYS and CPL were less pronounced.

Air Pollution↗