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1.
Correlation between plasmid DNA damage induced by PM10 and trace metals in inhalable particulate matters in Beijing air 总被引:2,自引:0,他引:2
Lü Senlin Shao Longyi Wu Minghong T. P. Jones L. Merolla R. J. Richard 《中国科学D辑(英文版)》2006,49(12):1323-1331
Based on the study of Beijing PM10 bioreactivity with the newly developed plasmid DNA assay method, and analysis for trace elements of PM10, the cause of plasmid DNA damage by PM10 was investigated. The study showed that plasmid DNA oxidative damages by PM10 are of difference in different seasons at various areas. The concentrations of TM50 of PM10 in whole samples respectively collected at urban and comparison sites during winter were 900 μg mL−1 and 74 μg mL−1, while those in their corresponding soluble fractions were 540 μg mL−1 and 86 μg mL−1. In contrast, TM50 contents of PM10 from summer whole samples at urban areas and comparison sites were 116 μg mL−1 and 210 μg mL−1, whereas those in their soluble fractions were 180 μg mL−1 and 306 μg mL−1. The difference of bioreactivity of Beijing PM10 resulted from the variation of trace elements. The oxidative damage of plasmid DNA caused by Pb, Zn, As in PM10 (whole sample) was relatively strong. TM50 and Mn, V, Zn display stronger correlation in the soluble fraction. It implies
that Zn could be the major trace element in Beijing PM10 which contributes to oxidative damage to plasmid DNA. 相似文献
2.
Zusammenfassung Die Anwendung der vonBergmeyer mitgeteilten enzymatischen Bestimmung von Glucose, Fructose und Saccharose in Gew?ssern erfordert bei Zuckerkonzentrationen
unter 50 μMol/l eine spezielle Vorbereitung des Analysengutes, die anhand eines Beispiels beschrieben wird. Reproduzierbarkeit
und analytische Ausbeute der Methode werden angegeben. Es wird auf die M?glichkeit hingewiesen, die Methodik auch bei der
Untersuchung geologischer Proben einzusetzen.
Summary Enzymatic analysis of glucose, fructose and sucrose by the method given byBergmeyer requires a special procedure when these sugars are determined in natural waters at concentrations below 50 μMol/l. The modified method, its reproducibility and analytical yield are described. The possibility of applying this method also to geological samples is considered.
Résumé Le méthode du dosage enzymatique de la glucose, la fructose et la saccharose, indiquée parBergmeyer, est modifiée pour les cas où ces sucres doivent être déterminés dans des eaux naturelles à des concentrations inférieures à 50 μMol/l. On examine la variation statistique et l'exploitation analytique de la méthode modifiée. Celle-ci pourrait également être utilisée pour l'analyse d'échantillons géologiques.相似文献
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Risk-based assessment of arsenic-affected aquacultural water in blackfoot disease hyperendemic areas
Cheng-Shin Jang Kao-Hung Lin Chen-Wuing Liu Ming-Chao Lin 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(5):603-612
This work explored a risk-based arsenic (As) regulation in farmed pond water by ingesting tilapia (Oreochromis mossambicus) in blackfoot disease hyperendemic areas and discussed a rational As regulation in pond water. Monte Carlo analysis was used
to propagate the parameter uncertainty and to assess probabilistically regulation risks. A dynamic scheme of groundwater management
was proposed that curves of utilization ratios against As concentrations in groundwater were established based on the risk-based
regulation. The 5th to 95th percentiles of risks range from 3.5 × 10−7 to 6.0 × 10−5 via ingesting the farmed tilapia under the current As regulation in farmed pond water in Taiwan, 50 μg/L. To compare to inorganic
As regulation in drinking water, the current As regulation in farmed pond water does not pose a great threat to human health,
but it is unsafe. Therefore, this study suggests that the regulation of As in farmed pond water is revised to be 25 μg/L. 相似文献
5.
A theoretical model is presented which allows computing the efficiency with which aerosol particles of 0.001 r1 m are collected by columnar ice crystals in air of various relative humidities, temperatures, and pressures. Particle capture due to Brownian diffusion, thermo- and diffusiophoresis is considered. It is shown that phoretic effects importantly determine the particle capture process of 0.01r1 m. The various pressure-temperature levels studied are found to affect the collection efficiency only ifr>0.1 m. Comparison shows that water drops generally are better aerosol particle scavengers than columnar ice crystals. 相似文献
6.
ZHANG HongFei XIAO Long ZHANG Li YUAN HongLin & JIN LanLan State Key Laboratory of Geological Processes Mineral Resources China University of Geosciences Wuhan China Faculty of Earth Sciences China University of Geosciences Wuhan China State Key Laboratory of Continental Dynamics Northwest University Xi’an China 《中国科学D辑(英文版)》2007,50(7):972-983
This paper reports geochemical and Pb-Sr-Nd isotopic compositions of the Indosinian Yangba (215 Ma),Nanyili (225 Ma) and Mopi granitoids from the Bikou block of the northwestern margin of the Yangtze plate. These granitoids are enriched in Al (Al2O3:14.56%―16.48%) and Sr (352 μg/g―1047 μg/g),and depleted in Y (<16 μg/g) and HREE (e.g. Yb<1.61 μg/g),resulting in high Sr/Y (36.3―150) and (La/Yb)N (7.8―36.3) ratios and strongly fractionationed REE patterns. The Indosinian granotoids show initial Sr isotopic ratios (ISr) from 0.70419 to 70752,εNd(t) values from-3.1 to -8.5,and initial Pb isotopic ratios 206Pb/204Pb=17.891-18.250,207Pb/204Pb=15.494-15.575,and 208Pb/204Pb=37.788-38.335. Their geochemi-cal signatures indicate that the granitoids are adakitic. However,they are distinct from some adakites,generated by partial melting of subducted oceanic slab and/or underplated basaltic lower crust,be-cause they have high K (K2O: 1.49%―3.84%) and evolved Nd isotopic compositions,with older Nd iso-topic model ages (TDM=1.06―1.83 Ga). Geochemical and Sr-Nd isotopic compositions suggest that the magmas of the Insoninian adakitic rocks in the Bikou block were derived from partial melting of thick-ened basaltic lower crust. Combined with regional analyses,a lithospheric delamination model after collision between the North China and South China plates can account for the Indosinian adakitic magma generation. On the other hand,based on the Pb-Sr-Nd isotopic probing to the magma sources of the adakitic rocks,it is suggested that there is an unexposed continent-type basement under the exposed Bikou Group volcanic rocks. This can constrain on the Bikou Group volcanic rocks not to be MORB-or OIB-type. 相似文献
7.
I. B. Boikov M. V. Kravchenko V. I. Kryuchko 《Izvestiya Physics of the Solid Earth》2010,46(4):339-349
Numerical algorithms are suggested for reconstructing the potential field in the region Ω = {0 ≤ R
0 ≤ ρ ≤ R, 0 ≤ θ ≤ π, 0 ≤ φ ≤ 2π} from its values on the surface Γ1 = {R,0 ≤ α1 ≤ θ ≤ α2 ≤ π, 0 ≤ β1 ≤ φ ≤ β2 ≤ π}. 相似文献
8.
Dr. Peter Perret 《Aquatic Sciences - Research Across Boundaries》1973,35(1):69-113
The Sempachersee (Switzerland), a facultatively oligomictic lake with visibility measuring according to Secchi of between
1.3 m and 12.9 m, is characterized by an oxygen minimum of 4 mg O2/l in the metalimnion in autumn and an almost total lack of oxygen in the greatest depths of the lake. Phosphate-phosphorus
is used up in the trophogenic zone and is found in quantities of between 20 and 24 μg/l during the overturn period. Nitrate-nitrogen
concentrations of between 0.55 and 0.6 mg/l are also present during overturn. Phanerogamic growth along the shore is sparse;
the variety of animal species as well as the respective number of organisms are limited although the reason for this has not
been determined.
相似文献
9.
Dynamical Nighttime Fog/Low Stratus Detection Based on Meteosat SEVIRI Data: A Feasibility Study 总被引:1,自引:0,他引:1
Automated detection of fog and low stratus in nighttime satellite data has been implemented on the basis of numerous satellite
systems in past decades. Commonly, differences in small-droplet emissivities at 11μm and 3.9μm are utilized. With Meteosat SEVIRI, however, this method cannot be applied with a fixed threshold due to instrument design:
The 3.9μm band is exceptionally wide and overlaps with the 4μm CO2 absorption band. Therefore, the emissivity difference varies with the length of the slant atmospheric column between sensor
and object. To account for this effect, the new technique presented in this paper is based on the dynamical extraction of
emissivity difference thresholds for different satellite viewing zenith angles. In this way, varying concentrations of CO2 and column depths are accounted for. The new scheme is exemplified in a plausibility study and shown to provide reliable
results. 相似文献
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Obtaining an accurate, value for total ozone under a cloudy sky, especially when the sun is not high, is a major remaining problem associated with total ozone measurements. The Toronto spectrophotometer has been designed with this in mind. It has been fitted with a polarizing prism, and measures light at four wavelengths simultaneous which makes it possible to obtain two independent double ratios. Clouds produce two effects on ozone measurements; the first is purely an optical effect which causes an apparent increase in ozone, the second is most likely a real increase in ozone associated with large cumulus-type clouds. By considering the three following points it is possible to distinguish between these two cloud effects and probably measure the true total ozone for solar zenith angles less than 80°: 1. The multiply scattered component of polarized light is used to reduce optical cloud variance. This makes all skies appear like thick coulds. 2. A double difference similar to the AD method is used but the two ratios of the double difference are weighted inversely with(=
1
-
2
for a pair). This further reduces the optical effects of clouds. 3. Real ozone increases due to large clouds are verified by comparing the increase of ozone obtained from one double difference to that of another. Differences between this multiply, polarized curve and the direct sun curve will be given, and a technique to obtain an accurate value of total ozone under all sky conditions, provided that the solar zenith angle is less than 80°, will be given. 相似文献
13.
A. N. Dzyuban 《Water Resources》2011,38(5):615-620
Concentration of dissolved methane was determined in the water of some tributaries of the Rybinsk Reservoir subject to different
anthropogenic impact; the features of its distribution and the extent of transformations in summer are shown. Its concentration
in water of the mouth areas varies within the limits of 2.2 to 280 μl CH4/l; the rate of methane oxidation is 0.01–230 μl CH4/(l day). Methanogenesis processes with a rate of 15–28 μl CH4/(l day) were recorded in surface waters of heavily polluted rivers. A correlation was found to exist between the characteristics
of methane cycle and the ecological conditions of the water body. 相似文献
14.
WANG Xiaorui GAO Shan LIU Xiaoming YUAN Honglin HU Zhaochu ZHANG Hong WANG Xuance 《中国科学D辑(英文版)》2006,49(9):904-914
The Yixian Formation at Sihetun in western Liao- ning Province has attracted considerable attention over the last two decades due to discovery of a wide range of well-preserved ‘feathered’ dinosaurs and primitive bird fossils[1―4]. This formation is dominated by vol- canic rocks, with fossil-bearing lacustrine sedimentary rocks at the upper part of the section[4]. The sedimen- tary rocks contain thin layers of tuff. According to previous studies[4], the total thickness of the Yixian Form… 相似文献
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16.
Predictive relations are developed for peak ground acceleration (PGA) from the engineering seismoscope (SRR) records of the
2001 Mw 7.7 Bhuj earthquake and 239 strong-motion records of 32 significant aftershocks of 3.1 ≤ Mw ≤ 5.6 at epicentral distances of 1 ≤ R ≤ 288 km. We have taken advantage of the recent increase in strong-motion data at
close distances to derive new attenuation relation for peak horizontal acceleration in the Kachchh seismic zone, Gujarat.
This new analysis uses the Joyner-Boore’s method for a magnitude-independent shape, based on geometrical spreading and anelastic
attenuation, for the attenuation curve. The resulting attenuation equation is,
where, Y is peak horizontal acceleration in g, Mw is moment magnitude, rjb is the closest distance to the surface projection of the fault rupture in kilometers, and S is a variable taking the values
of 0 and 1 according to the local site geology. S is 0 for a rock site, and, S is 1 for a soil site. The relation differs
from previous work in the improved reliability of input parameters and large numbers of strong-motion PGA data recorded at
short distances (0–50 km) from the source. The relation is in demonstrable agreement with the recorded strong-ground motion
data from earthquakes of Mw 3.5, 4.1, 4.5, 5.6, and 7.7. There are insufficient data from the Kachchh region to adequately judge the relation for the
magnitude range 5.7 ≤ Mw ≤ 7.7. But, our ground-motion prediction model shows a reasonable correlation with the PGA data of the 29 March, 1999 Chamoli
main shock (Mw 6.5), validating our ground-motion attenuation model for an Mw6.5 event. However, our ground-motion prediction shows no correlation with the PGA data of the 10 December, 1967 Koyna main
shock (Mw 6.3). Our ground-motion predictions show more scatter in estimated residual for the distance range (0–30 km), which could
be due to the amplification/noise at near stations situated in the Kachchh sedimentary basin. We also noticed smaller residuals
for the distance range (30–300 km), which could be due to less amplification/noise at sites distant from the Kachchh basin.
However, the observed less residuals for the longer distance range (100–300 km) are less reliable due to the lack of available
PGA values in the same distance range. 相似文献
17.
R. Signer F. v. Beust Ulrich A. Corti 《Aquatic Sciences - Research Across Boundaries》1951,13(1):31-35
Summary The investigation with an electron-microscope of the scales of the fresh water fish,Leuciscus rutilus L., showed that their ventral “smooth” surface scems to be formed like a corrugated plate with a distance between the ridges
of 1–2 μ. The dorsal “rough” side of the scales shows a very fine roughness. It is interrupted by pointed combs of the same
structure in a regular distance of 16–27 μ. The thickness of these combs is of about 1 μ at their base, their height of about
5–10 μ. It seems probable that the surface of scales is partially covered with laminas of hyalodentine or guanine.
13. Mitteilung siehe diese Zeitschrift,13, 29–30 (1951). 相似文献
13. Mitteilung siehe diese Zeitschrift,13, 29–30 (1951). 相似文献
18.
The toxicity of Na-pentachlorophenate to Viviparus bengalensis is investigated by batch tests with daily exchange of medium in the temperature range between 19 °C (February), 27 °C (April), 32 °C (June) and 30 °C (August) at times of exposure between 12 and 96 h. In the range of higher concentrations, pronounced abnormalities in behaviour by secreting mucus and discharging eggs and embryos occur. The LC50 are lowest for all times of exposure at 27 °C, whereas the times of survival with a given concentration are highest at 30 °C. From the LC50, 96h, 27°C = 66 μg/l results a safe concentration of only 47 μg/l Na-pentachlorophenate for Viviparus bengalensis. 相似文献
19.
Hydrochemistry of high altitude alpine lakes 总被引:4,自引:0,他引:4
Dott. Rosario Mosello 《Aquatic Sciences - Research Across Boundaries》1984,46(1):86-99
The chemical characteristics of 320 Italian alpine lakes are presented and discussed: 38% of them have low ionic concentrations
and conductivities below 20 μS/cm; 56% show a conductivity range of 20.1 to 200 μS/cm, and 6% are characterized by higher
solute concentrations, up to 34.5 meq/l, with a corresponding maximum conductivity of 1,265 μS/cm. 相似文献
20.
Geochemical fractionation of rare earth elements in lacustrine deposits from Qaidam Basin 总被引:1,自引:0,他引:1
HuCai Zhang WenXiang Zhang FengQin Chang LunQing Yang GuoLiang Lei MingSheng Yang Yang Pu YangBin Lei 《中国科学D辑(英文版)》2009,52(11):1703-1713
Based on the concentration and distribution pattern analysis of the rare earth elements (REEs) at the Shell Bar section from
Qaidam Basin, we studied the geochemical fractionations of REE in paleolake deposits and their paleo-environmental significance.
Our results show that the REE concentration in AS (acid soluble) and AR (acid residual) fractions are 20.9 μg/g and 95.4 μg/g
(except element Y) individually, showing a strong REE differentiation between AS and AR fractions. However, the two types
of fractions (AS & AR) have similar REE distribution patterns, which are slightly rich in light earth rare elements (LREEs),
with slightly right-tilting and negative Eu anomaly. The LREE of AR is richer than that of AS. There were no significant correlations
between the REE in AS, AR and other proxies. It indicated that the lacustrine deposition had different material sources and
experienced varying geochemical procedures. Correlation analysis between the REE and the content of fine grain-size (<4 μm)
of the sediments, Rb/Sr ratio and Mn concentration showed high correlation coefficients. Our results demonstrated that the
REE in acid soluble and residual fractions bear different environmental significances, which are strongly dependent on local
environment. The REE of acid soluble fraction is closely related to the paleoclimatic changes in the lake catchment and the
evolutionary processes of lake itself. Our results suggest that δCe and (La/Yb)n could be used as proxies of the reduction-oxidation conditions and furthermore the temperature change and the lake level
fluctuations. Using these proxies, we reconstructed the paleoclimate and water level fluctuation history during the high lake
level period lasting between 43.5 and 22.4 cal. ka BP. 相似文献