大棚塑料薄膜的使用与保管

塑料薄膜在使用过程中,经受风吹、日晒、雨淋等影响,会使塑料分子发生分解、断链、氧化等,或使增塑剂析出,造成薄膜出现斑点、变色、变脆等,机械强度和伸缩率降低。因此在使用时应注意做到:轻拉轻放,轻揭轻盖,不要猛拉硬扯。棚架上有核杈尖梢的要设法整平,缠上草绳。钢架要打磨涂漆,防止铁锈和毛刺污染损伤薄膜。中小拱棚要改进压膜方式,采用拱杆和压杆,或用竖杆搪、横杆压的方式,使双杆夹住薄膜,不要随便用砖头、石块、木棍压膜。冬季当棚面结霜或冻冰时,不易敲打或震动棚面。

下肢骨折外固定支架术的护理

我院自1997年至今对下肢骨折适合作外固定的病人及患肢污染损伤严重不能做内固定的病人32例,行单侧外固定支架固定术。其中股骨骨折3例,胫腓骨折29例。结果一期愈合30例,2例二期手术植皮而愈,获得满意效果。

Storage and Spatial Variation of Phosphorus in Paddy Soils of China

Due to the growing concern about the agricultural phosphorus (P) losses pollution, an in-depth understanding of P in paddy soils of China would be helpful in providing a national perspective of the environmental impact of P cycling and fertility on China's farms. In this study, we evaluated the P storage and the P density of paddy soils in China, characterized the spatial variations of P among the subgroups of paddy soils and soil regions in China, and evaluated the P data using GIS-based analysis, which included a newly compiled 1:1 000 000 digital soil map of China, and using 1 490 soil profiles. The available and total P densities of paddy soils were 6.7 and 698.5 g m -3 , respectively. Overall in China, the total P storage within 1 m of paddy soils was estimated to be 330.2 Tg. The P density of paddy soils varied substantially with subgroups due to the different soil water regimes such as groundwater table and soil drainage. The P availability in paddy soils, especially in surface layer, was higher in high temperature and precipitation areas. Further research is needed to examine more anthropogenic impact factors, such as increasing use of chemical fertilizer.

Estimation of Non-point Source Pollution Loads Under Uncertain Information

Many kinds of uncertainties are involved, such as random, fuzzy, grey, unascertained property and so on, in soil erosion process. To exactly predict the non-point source pollution loads, some uncertainties should be taken into consideration. Aiming at the deficiency of present blind number theory being helpless for fuzziness, a novel blind number, i.e. extended-blind number, was introduced by substituting a set of triangular fuzzy numbers （TFNs）, expressed as a-cuts, for interval values in present blind number, and the expected value of extended-blind number was also brought forward by referring to the current blind number theory. On the basis of denoting the parameters of Uni- versal Soil Loss Equation （USLE） as extended-blind parameters, a novel USLE model was established for quantitatively evaluating soil erosion loss and non-point source pollution loads. As a case, the uncertain USLE was employed for predicting the soil erosion loss and non-point source pollution loads of absorbed nitrogen and phosphorus in a dis- trict in the Hangbu-Fengle River basin, in the upstream of Chaohu Lake watershed. The results show that it is feasible in theory to extend blind number into fuzzy environment and reliable on conclusion to apply extended-blind number theory for predicting non-point source pollution loads.

Problems of Marine Ecological and Environmental Compensations of Oil Spill in China

In recent years, the frequent occurrences of marine oil spills have already become one of the major reasons threatening the marine ecological safety of China. In the event of oil spill, oth-er than taking the necessary emergent measures aiming specifically at the damage to the marine ecology and environment, using legal means to assure that the damage liabilities are borne by the respon-sible persons to protect the national interests are also very neces-sary. This paper advances five recommendations regarding the development of a system for ecological legal compensations from the standpoint of the current status of legislation and execution of the laws on compensation of oil spill polluting marine ecosystem. These five recommendations include: determination of the status of juristic action in marine ecological and environmental compen-sations in accordance with the laws, determination of plaintiff of marine ecological and environmental compensations in accordance with the laws, determination of the four basic principles in the le-gal actions of marine ecological and environmental compensations in accordance with the laws, determination of assessment technical standard of marine ecological and environmental damages in ac-cordance with the laws, and determination of the scope of marine ecological and environmental compensations in accordance with the laws.

Midkine secretion protects Hep3B cells from cadmium induced cellular damage

AIM： To evaluate role Cadmium （Cd） exposure line Hep3B cells. of midkine secretion during in the human hepatocyte cell METHODS： Different dosages of Cd （0.5-1-5-10 μg/mL） were applied to Hep3B cells and their effects to apoptosis, lactate dehydrogenase （LDH） leakage and midkine secretion were evaluated as time dependent manner. Same experiments were repeated with exogenously applied midkine （250-5000 pg/mL） and/or 5 t^g/mL Cd. RESULTS： Cd exposure induced prominent apoptosis and LDH leakage beginning from lower dosages at the 48^th. Cd induced midkine secretion with higher dosages （P 〈 0.001）, （control, Cd 0.5-1-5-10μg/mL respectively： 1123 ± 73, 1157 ± 63, 1242 ± 90, 1886 ± 175, 1712 ± 166 pg/mL）. Exogenous 500-5000 pg/mL midkine application during 5 μg/mL Cd toxicity prevented caspase-3 activation （control, Cd toxicity, 250, 500, 1000, 2500, 5000 pg/mL midkine＋ Cd toxicity, respectively： 374 ± 64, 1786 ± 156, 1545 ± 179, 1203 ± 113, 974 ± 116, 646 ± 56, 556 ± 63 cfu） LDH leakage and cell death in Hep3B cells （P 〈 0.001）. CONCLUSION： Our results showed that midkine secretion from Hep3B cells during Cd exposure protects liver cells from Cd induced cellular damage. Midkine has anti-apoptotic and cytoprotective role during Cd toxicity. Further studies are needed to explain the mechanism of midkine secretion and cytoprotective role of midkine during Cd exposure. Midkine may be a promising theurapatic agent in different toxic hepatic diseases.

Evaluation of the Contribution of Aerosols in the Contamination of the Environment in the Greater Casablanca

The Greater Casablanca, like the other large cities, has experienced significant urban and industrial development in recent years, this development has certainly helped develop the productive fabric, generate significant employment opportunities for hundreds of thousands of families, but at the expense of the mobility and quality of the environment particularly those of the air. The deterioration of the air quality affects more and more the population＇s health with significant cost and damage to the community, this study aims to quantify the degree of aerosols pollution damage and also its health effects.

Enzyme-Containing Paints Inhibit the Growth of Marine Microorganisms

A new strategy to prevent the biofouling of water-submerged surfaces is presented here. In particular, the authors showthat carbonic anydrase from Methanosarcina thermophila can be entrapped into polyacrylic paints, preserving enzyme activity. In addition, the authors also show that enzyme-containing paints inhibit the growth of marine microorganims, preventing biofouling.

Formation damage control of high permeability sandstone reservoir

The concern on formation damage control of high permeability sandstone reservoir has been growing in oil industry in recent years. The invasion of particles and the filtrate of drilling fluid are proven as one of the key factors accounting for reservoir damage. Based on the ideal packing theory, the practical software has been developed to optimize the blending proportion of several bridging agents, and the core flooding tests were conducted to evaluate return permeability of core samples contaminated with different drilling fluids. Experimental results show that the ideal packing approach can reduce the dynamic filtration rate, improve the return permeability and drawdown the breakthrough pressure, indicating that this kind of drilling fluids can meet the demands of formation damage control for high permeability sandstone reservoirs. Some applying procedures for formation damage control are also proposed in this paper.

Compensation for Damage to Marine Biodiversity under International Liability Regime on Vessel-Source Marine Oil Pollution Damage

Vessel-source marine oil pollution damage is governed by an international liability regime, including the CLC treaties, 2001 Bunker Convention and the 1977 Seabed Convention. Despite that ＂pollution damage＂ in these treaties does not exclude damage to marine biodiversity, the fact that damage to marine biodiversity is not mentioned in this regime arouses the question of compensability of damage to marine biodiversity under the regime. This article attempts to investigate this question from the perspectives of the relationship between marine environmental damage and damage to marine biodiversity and the possibility of compensation for damage to marine biodiversity under the regime. While the findings of this article reveal that the regime cannot provide sufficient compensation for such damage, this article in the conclusion offers some suggestions for the sake of remedying of damaged marine biodiversity under the regime.

Gas-to-particle conversion of atmospheric ammonia and sampling artifacts of ammonium in spring of Beijing

PM2.5 and gaseous pollutants(SO2,HNO2,HNO3,HCl,and NH3) were simultaneously collected by Partisol- Model 2300 Sequential Speciation Sampler with denuder-filter pack system in the spring of 2013 in Beijing.Water-soluble inorganic ions and gaseous pollutants were measured by Ion Chromatography.Results showed that the concentrations of NH3,NH+ 4and PM2.5 had similar diurnal variation trends and their concentrations were higher at night than in daytime.The results of gas-to-particle conversion revealed that [NH3]:[NH+4] ratio was usually higher than 1; however,it was less than 1 and the concentration of NH+4 increased significantly during the haze episode,indicating that NH3 played an important role in the formation of fine particle.Research on the sampling artifacts suggested that the volatilization loss of NH+4 was prevalent in the traditional single filter-based sampling.The excess loss of HNO3 and HCl resulted from ammonium-poor aerosols and semivolatile inorganic species had severe losses in the clean day,whereas the mass of NH+ 4was usually overestimated during the single filter-based sampling due to the positive artifacts.Correlation analysis was used to evaluate the influence of meteorological conditions on the volatilization loss of NH+4.It was found that the average relative humidity and temperature had great effects on the loss of NH+4.The loss of NH+4 was significantly under high temperature and low humidity,and tended to increase with the increasing of absorption of gaseous pollutants by denuder.The total mass of volatile loss of NH+4,NO- 3and Cl- could not be ignored and its maximum value was 12.17 μg m-3.Therefore it is important to compensate sampling artifacts for semivolatile inorganic species.

Phyto-Toxicity of Chromium in Maize： Oxidative Damage, Osmolyte Accumulation, Anti-Oxidative Defense and Chromium Uptake

Agricultural production systems are immensely exposed to different environmental stresses in which heavy metal stress receives serious concerns. This study was conducted to explore the deleterious effects of different chromium （Cr） stress levels, i.e., O, 30, 60, 90, 120, and 150 μmol L^-1, on two maize genotypes, Wandan 13 and Runnong 35. Both genotypes were evaluated by measuring their growth and yield characteristics, Cr accumulation in different plant tissues, alterations in osmolyte accumulation, generation of reactive oxygen species （ROS）, and anti-oxidative enzyme activity to scavenge ROS. The results showed that Cr stress decreased the leaf area, cob formation, 100-grain weight, shoot fresh biomass, and yield formation, while Cr accumulation in different maize tissues was found in the order of roots 〉 leaves 〉 stem ~ seeds in both genotypes. The increased Cr toxicity resulted in higher free proline, soluble sugars and total phenolic contents, and lower soluble protein contents. However, enhanced lipid peroxidation was noticed in the forms of malondialdehyde, hydrogen peroxide （H2O2） and thiobarbituric acid reactive substance accumulation, and electrolyte leakage. The hyperactivity of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, especially glutathione peroxidase and glutathione reductase indicated that these anti-oxidative enzymes had a central role in protecting maize from Cr toxicity, especially for Wandan 13. Moreover, higher uptake and less translocation of Cr contents into the grains of Wandan 13 implied its importance as a potential candidate against soil Cr pollution.

Interspecies variation in DNA damage induced by pollution

The choice of a suitable species to translate pollution signals into a quantitative monitor is a fundamental step in biomonitoring plans. Here we present the results of three years of biomonitoring at a new coal power plant in central Italy using three different aquatic and terrestrial wildlife species in order to compare their reliability as sentinel organisms for genotoxicity. The comet assay was applied to the common land snail Helix spp., the lagoon fish Aphaniusfasciatus, and the green frog Rana esculenta sampled in the area potentially exposed to the impact of the power station. The tissue concentration of some expected pollutants （As, Cd, Ni, Pb, Cr） was analysed in parallel samples collected in the same sampling sites. The three species showed different values in the comet assay （Tail Intensity） and different accumulation profiles of heavy metals. Aphanius fasciatus showed an increasing genotoxic effect over time that paralleled the temporal increase of the heavy metals, especially arsenic, and the highest correlation between heavy metals and DNA damage. Helix spp. showed levels of damage inversely related to the distance from the source of pollution and in partial accordance with the total accumulation of trace elements. On the contrary, Rana esculenta showed a low capability to accumulate metals and had inconsistent results in the comet test. The fish appeared to be the most efficient and sensitive species in detecting chemical pollution. Overall, both the fish and the snail reflected a trend of increasing pollution in the area surrounding the power plant across time and space [Current Zoology 60 （2）： 308-321, 2014].