Refinar búsqueda
Resultados 3551-3560 de 4,043
Productive performance, egg quality, blood constituents, immune functions, and antioxidant parameters in laying hens fed diets with different levels of Yucca schidigera extract Texto completo
2016
Alagawany, Mahmoud | Abd El-Hack, Mohamed E. | El-Kholy, Mohamed S.
This study evaluated the effect of Yucca schidigera extract on productive performance, egg quality, blood metabolites, immune function, and antioxidant parameters in laying hens. A total of 96 36-week-old hens were allocated into four groups, the control diet or the diet supplemented with 50, 100, or 150 mg/kg of yucca extract, from 36 to 52 weeks of age. Hens were divided into four equal groups replicated six times with four hens per replicate. As a result of this study, there were no linearly or quadratically differences in body weight change (BWC), feed consumption (FC), feed conversion ratio (FCR), and egg weight (EW) due to yucca treatments at different ages, except FCR and EW that were improved with yucca supplementation during 36–40 weeks of age. Supplemental dietary yucca up to 100 mg/kg diet led to significant improvement in egg number (EN) and egg mass (EM). Egg qualities were not linearly or quadratically affected by yucca treatments except shell thickness was quadratically (P < 0.001) increased with increasing yucca level up to 100 mg/kg diet. Dietary supplementation of yucca exhibited a positive impact on albumin and immunoglobulin G (IgG). Comparing to the control group, yucca addition to laying hen diets resulted in a significant linear (P < 0.001) and quadratic (P = 0. 010) decrease in blood ammonia-N and urea-N, respectively. The activity of superoxide dismutase (SOD) and reduced glutathione (GSH) level in serum were quadratically improved in yucca groups. The malondialdehyde (MDA) concentration was decreased with yucca addition in comparison with the control group. In conclusion, yucca supplemented up to 100 mg/kg diet can be used as effective feed additive to improve productive performance, blood profile, and antioxidant enzyme activities in laying hens.
Mostrar más [+] Menos [-]Hospital admissions due to diseases of arteries and veins peaked at physiological equivalent temperature −10 to 10 °C in Germany in 2009–2011 Texto completo
2016
Shiue, Ivy | Perkins, David R. | Bearman, Nick
We aimed to understand relationships of the weather as biometeorological and hospital admissions due to diseases of arteries and veins by subtypes, which have been scarcely studied, in a national setting in recent years. This is an ecological study. Ten percent of daily hospital admissions from the included hospitals (n = 1,618) across Germany that were available between 1 January 2009 and 31 December 2011 (n = 5,235,600) were extracted from Statistisches Bundesamt, Germany. We identified I70-I79 Diseases of arteries, arterioles and capillaries and I80-I89 Diseases of veins, lymphatic vessels and lymph nodes by International Classification of Diseases version 10 as the study outcomes. Daily weather data from 64 weather stations that covered 13 German states including air temperature, humidity, wind speed, cloud cover, radiation flux and vapour pressure were obtained and generated into physiologically equivalent temperature (PET). Two-way fractional-polynomial prediction was plotted with 95 % confidence intervals. For most of the subtypes from diseases of arteries and veins, hospital admissions slightly peaked in spring and dropped when PET was at 10 °C. There were no other large differences across 12 months. Admissions of peripheral vascular diseases, arterial embolism and thrombosis, phlebitis and thrombophlebitis, oesophageal varices and nonspecific lymphadenitis peaked when PET was between 0 and −10 °C, while others peaked when PET was between 0 and 10 °C. More medical resources could have been needed on days when PETs were at −10 to 10 °C than on other days. Adaptation to such weather change for health professionals and the general public would seem to be imperative.
Mostrar más [+] Menos [-]Dust aerosol properties and radiative forcing observed in spring during 2001–2014 over urban Beijing, China Texto completo
2016
Yu, Xingna | Lu, Rui | Kumar, K Raghavendra | Ma, Jia | Zhang, Qiuju | Jiang, Yilun | Kang, Na | Yang, Suying | Wang, Jing | Li, Mei
The ground-based characteristics (optical and radiative properties) of dust aerosols measured during the springtime between 2001 and 2014 were investigated over urban Beijing, China. The seasonal averaged aerosol optical depth (AOD) during spring of 2001–2014 was about 0.78 at 440 nm. During dust days, higher AOD occurred associated with lower Ångström exponent (AE). The mean AE₄₄₀–₈₇₀ in the springtime was about 1.0, indicating dominance of fine particles over the region. The back-trajectory analysis revealed that the dust was transported from the deserts of Inner Mongolia and Mongolia arid regions to Beijing. The aerosol volume size distribution showed a bimodal distribution pattern, with its highest peak observed in coarse mode for all episodes (especially for dust days with increased volume concentration). The single scattering albedo (SSA) increased with wavelength on dust days, indicating the presence of more scattering particles. Furthermore, the complex parts (real and imaginary) of refractive index showed distinct characteristics with lower imaginary values (also scattering) on dust days. The shortwave (SW; 0.2–4.0 μm) and longwave (LW; 4–100 μm) aerosol radiative forcing (ARF) values were computed from the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model both at the top of atmosphere (TOA) and the bottom of atmosphere (BOA) during dust and non-dust (dust free) days, and the corresponding heating rates and forcing efficiencies were also estimated. The SW (LW) ARF, therefore, produced significant cooling (warming) effects at both the TOA and the BOA over Beijing.
Mostrar más [+] Menos [-]Active biomonitoring of palladium, platinum, and rhodium emissions from road traffic using transplanted moss Texto completo
2016
Suoranta, Terhi | Niemelä, Matti | Poikolainen, Jarmo | Piispanen, Juha | Bokhari, Syed Nadeem Hussain | Meisel, Thomas | Perämäki, Paavo
Active biomonitoring of palladium, platinum, and rhodium emissions from road traffic using transplanted moss Texto completo
2016
Suoranta, Terhi | Niemelä, Matti | Poikolainen, Jarmo | Piispanen, Juha | Bokhari, Syed Nadeem Hussain | Meisel, Thomas | Perämäki, Paavo
The use of transplanted moss (Pleurozium schreberi) in active biomonitoring of traffic-related emissions of Pd, Pt, and Rh was studied. Moss mats were transplanted to three locations along highway E75 (in Oulu, Finland) at three different distances from the highway. Five samples were collected from a background site after the same exposure period. Mass fractions of Pd, Pt, and Rh as well as mass fractions of 18 other elements were determined in these samples. The results indicated that P. schreberi is well suited for active biomonitoring of Pd, Pt, and Rh. Mass fractions above the background values were observed in the samples exposed to traffic-related emissions. When the results were compared with those of the other elements, high correlations of Pd, Pt, and Rh with commonly traffic-related elements (e.g., Cu, Ni, Sb, Zn, etc.) were found. It was also found that the amounts of Pd, Pt, and Rh in moss samples decreased when the distance to the highway increased. This trend gives evidence for the suitability of P. schreberi for active biomonitoring of Pd, Pt, and Rh. Furthermore, it can be concluded that the mass fractions determined in this study provide valuable evidence about the current state of Pd, Pt, and Rh emissions in Oulu, Finland.
Mostrar más [+] Menos [-]Active biomonitoring of palladium, platinum, and rhodium emissions from road traffic using transplanted moss Texto completo
2016
Suoranta, Terhi | Niemelä, Matti | Poikolainen, Jarmo | Piispanen, Juha | Hussain Bokhari, Syed Nadeem | Meisel, Thomas | Perämäki, Paavo | University of Oulu, Research Unit of Sustainable Chemistry | Montanuniversität Leoben, Austria | Luke / Luonnonvarat ja biotuotanto / Ympäristövaikutukset / Maaperä ekosysteeminä (4100100414) | 4100100414
Toward better understanding and feasibility of controlling greenhouse gas emissions from treatment of industrial wastewater with activated sludge Texto completo
2016
Chen, Wei-Hsiang | Yang, Jun-Hong | Yuan, Chung-Shin | Yang, Ying-Hsien
Wastewater treatment plants (WWTPs) have been recognized as important sources for anthropogenic greenhouse gas (GHG) emission. The objective of the study was to thoroughly investigate a typical industrial WWTP in southern Taiwan in winter and summer which possesses the emission factors close to those reported values, with the analyses of emission factors, mass fluxes, fugacity, lab-scale in situ experiments, and impact assessment. The activated sludge was the important source in winter and summer, and nitrous oxide (N₂O) was the main contributor (e.g., 57 to 91 % of total GHG emission in a unit of kg carbon dioxide-equivalent/kg chemical oxygen demand). Albeit important for the GHGs in the atmosphere, the fractional contribution of the GHG emission to the carbon or nitrogen removal in wastewater treatment was negligible (e.g., less than 1.5 %). In comparison with the sludge concentration or retention time, adjusting the aeration rate was more effective to diminish the GHG emission in the activated sludge without significantly affecting the treated water quality. When the aeration rate in the activated sludge simulation was reduced by 75 %, the mass flux of N₂O could be diminished by up to 53 % (from 9.6 to 4.5 mg/m²-day). The total emission in the WWTP (including carbon dioxide, methane, and N₂O) would decrease by 46 % (from 0.67 to 0.36 kg CO₂-equiv/kg COD). However, the more important benefit of changing the aeration rate was lowering the energy consumption in operation of the WWTP, as the fractional contribution of pumping to the total emission from the WWTP ranged from 46 to 93 % within the range of the aeration rate tested. Under the circumstance in which reducing the burden of climate change is a global campaign, the findings provide insight regarding the GHG emission from treatment of industrial wastewater and the associated impact on the treatment performance and possible mitigation strategies by operational modifications.
Mostrar más [+] Menos [-]Dielectric barrier discharge plasma induced degradation of aqueous atrazine Texto completo
2016
Feng, Jingwei | Jiang, Lin | Zhu, Dan | Su, Kuizu | Zhao, Dayong | Zhang, Jibiao | Zheng, Zheng
Degradation of herbicide atrazine in aqueous solution was investigated using a plate type dielectric barrier discharge (DBD) plasma reactor. DBD plasma was generated at the gas-liquid interface of the formed water film. At discharge time of 14 min, atrazine was degradated effectively with a degradation rate of 99 % at the discharge power of 200 W. The experimental data fitted well with first-order kinetics and the energy efficiency for 90 % degradation of atrazine (G value) was calculated, obtaining a rate constant of 0.35 min⁻¹ and a G value of 1.27 × 10⁻¹⁰ mol J⁻¹ (98.76 mg kW⁻¹ h⁻¹) at a discharge power of 200 W, respectively. The addition of Fe²⁺ increased the rate constant and G value dramatically, and a significant decrease of the rate constant and G value was observed with the addition of radical scavengers (tert-butyl alcohol, isopropyl alcohol, or Na₂CO₃). The generated aqueous O₃ and H₂O₂ were determined, which promoted the degradation of herbicide atrazine. Dechlorination was observed and the experimentally detected Cl⁻ was 1.52 mg L⁻¹ at a discharge time of 14 min. The degradation intermediates of atrazine were detected by means of liquid chromatography-mass spectrometry; dechlorination, hydroxylation, dealkylation, and alkyl oxidation processes were involved in the degradation pathways of atrazine.
Mostrar más [+] Menos [-]Brominated flame retardants in the hair and serum samples from an e-waste recycling area in southeastern China: the possibility of using hair for biomonitoring Texto completo
2016
Liang, Si | Xu, Feng | Tang, Weibiao | Zhang, Zheng | Zhang, Wei | Liu, Lili | Wang, Junxia | Lin, Kuangfei
Hair samples and paired serum samples were collected from e-waste and urban areas in Wenling of Zhejiang Province, China. The PBDE and DBDPE concentrations in hair and serum samples from e-waste workers were significantly higher than those of non-occupational residents and urban residents. BDE209 was the dominating BFRs in hair and serum samples from the e-waste area, while DBDPE was the major BFRs from the urban area. Statistically significant correlations were observed between hair level and serum level for some substances (BDE209, DBDPE, BDE99, BDE47, BDE28, and BDE17), although the PBDE congener profiles in hair were different from those in the serum. A statistically significant positive correlation between the PBDE concentrations and the working age, as well as gender difference, was observed in e-waste workers. Different sources of PBDEs and DBDPE in three groups were identified by principal component analysis and spearman correlation coefficient. Hair is suggested to be a useful matrix for biomonitoring the PBDE exposure in humans.
Mostrar más [+] Menos [-]Sublethal concentrations of silver nanoparticles affect the mechanical stability of biofilms Texto completo
2016
Grün, Alexandra Y. | Meier, Jutta | Metreveli, George | Schaumann, Gabriele E. | Manz, Werner
Bacterial biofilms are most likely confronted with silver nanoparticles (Ag NPs) as a pollutant stressor in aquatic systems. In this study, biofilms of Aquabacterium citratiphilum were exposed for 20 h to 30 and 70 nm citrate stabilized Ag NPs in low-dose concentrations ranging from 600 to 2400 μg l⁻¹, and the Ag NP-mediated effects on descriptive, structural, and functional biofilm characteristics, including viability, protein content, architecture, and mechanical stability, were investigated. Viability, based on the bacterial cell membrane integrity of A. citratiphilum, as determined by epifluorescence microscopy, remained unaffected after Ag NP exposure. Moreover, in contrast to information in the current literature, protein contents of cells and extracellular polymeric substances (EPS) and biofilm architecture, including dry mass, thickness, and density, were not significantly impacted by exposure to Ag NPs. However, the biofilms themselves served as effective sinks for Ag NPs, exhibiting enrichment factors from 5 to 8. Biofilms showed a greater capacity to accumulate 30 nm sized Ag NPs than 70 nm Ag NPs. Furthermore, Ag NPs significantly threatened the mechanical stability of biofilms, as determined by a newly developed assay. For 30 nm Ag NPs, the mechanical stability of biofilms decreased as the Ag NP concentrations applied to them increased. In contrast, 70 nm Ag NPs produced a similar decrease in mechanical stability for each applied concentration. Overall, this finding demonstrates that exposure to Ag NPs triggers remarkable changes in biofilm adhesion and/or cohesiveness. Because of biofilm-mediated ecological services, this response raises environmental concerns regarding Ag NP release into freshwater systems, even in sublethal concentrations.
Mostrar más [+] Menos [-]Mechanisms of biochar-mediated alleviation of toxicity of trace elements in plants: a critical review Texto completo
2016
Rizwan, Muhammad | Ali, Shafaqat | Qayyum, Muhammad Farooq | Ibrahim, Muhammad | Zia-ur-Rehman, Muhammad | Abbas, Tahir | Ok, Yong Sik
Trace elements (TEs) contamination is one of the main abiotic stresses which limit plant growth and deteriorate the food quality by their entry into food chain. In recent, biochar (BC) soil amendment has been widely reported for the reduction of TE(s) uptake and toxicity in plants. This review summarizes the role of BC in enhancing TE(s) tolerance in plants. Under TE(s) stress, BC application increased plant growth, biomass, photosynthetic pigments, grain yield, and quality. The key mechanisms evoked are immobilization of TE(s) in the soil, increase in soil pH, alteration of TE(s) redox state in the soil, and improvement in soil physical and biological properties under TE(s) stress. However, these mechanisms vary with plant species, genotypes, growth conditions, duration of stress imposed, BC type, and preparation methods. This review highlights the potential for improving plant resistance to TE(s) stress by BC application and provides a theoretical basis for application of BC in TE(s) contaminated soils worldwide.
Mostrar más [+] Menos [-]Eco-environmental impact of inter-basin water transfer projects: a review Texto completo
2016
Zhuang, Wen
The objective reality of uneven water resource distribution and imbalanced water demand of the human society makes it inevitable to transfer water. It has been an age-old method to adopt the inter-basin water transfers (IBTs) for alleviating and even resolving the urgent demand of the water-deficient areas. A number of countries have made attempts and have achieved enormous benefits. However, IBTs inevitably involve the redistribution of water resources in relevant basins and may cause changes of the ecological environment in different basins. Such changes are two-sided, namely, the positive impacts, including adding new basins for water-deficient areas, facilitating water cycle, improving meteorological conditions in the recipient basins, mitigating ecological water shortage, repairing the damaged ecological system, and preserving the endangered wild fauna and flora, as well as the negative impacts, including salinization and aridification of the donor basins, damage to the ecological environment of the donor basins and the both sides of the conveying channel system, increase of water consumption in the recipient basins, and spread of diseases, etc. Because IBTs have enormous ecological risk, it is necessary to comprehensively analyze the inter-basin water balance relationship, coordinate the possible conflicts and environmental quality problems between regions, and strengthen the argumentation of the ecological risk of water transfer and eco-compensation measures. In addition, there are some effective alternative measures for IBTs, such as attaching importance to water cycle, improving water use efficiency, developing sea water desalination, and rainwater harvesting technology, etc.
Mostrar más [+] Menos [-]