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941.
Gangba sheep are known for having typical sensory characteristics attributed to free range conditions and grazing on wild plants. The genuine Gangba mutton was selected as the experimental group, and the commercial Tibetan mutton was selected as the control group, the nutritive composition of basic chemical components, amino acids and fatty acids in mutton were investigated to correlate its unique meat quality and eating satisfaction. The results showed that fatty acids were significantly higher (P<0.05) in Gangba mutton than in commercial mutton, and the higher content of flavoring amino acids (glutamic acid and aspartame) were primarily responsible for the taste attributes umami of meat juices. Moreover, the trace elements analysis in mutton and grazing factors (forage, water source and soil) were conducted, to explain the source of essential trace elements in mutton. The concentrations of essential trace elements show that the Gangba mutton was a valuable source for highly available Cu and Zn in human nutrition, and well managed with few detected of toxicity metal. The concentrations of essential trace elements in mutton are closely related to the trace elements in environmental grazing factors. In conclusion, the congenital grazing conditions (a highly mineralized water resource, natural forages and clean soils) were shown to contribute to the unique meat characteristics of Gangba sheep. 相似文献
942.
Kun Xu Haiwei Wang Xuechen Liang Ying Tan Xianping Yao Pixin Wang 《Journal of Polymers and the Environment》2018,26(7):2782-2792
Cationic hyperbranched oligomer poly(N-acryloyl-1,2-diaminoethane hydrochloride) (HADE) was firstly synthesized by Michael addition reaction. And then, a series of cationic flocculants poly(acrylamide/N-acryloyl-1,2-diaminoethane hydrochlorides) (PAM-HADEs) with hyperbranched structure was prepared from HADE as macro-monomer and acrylamide (AM). The structures of PAM-HADEs were characterized by Fourier transform infrared spectrometry, 1H and 13C nuclear magnetic resonance spectroscopy, gel permeation chromatography (GPC) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF). And the properties were systematically evaluated by intrinsic viscosity, zeta potential and hydrodynamic radius. The mechanism of the cationic hyperbranched copolymer used in water treatment was extensively studied via a jar test in which the transmittance of the supernatant, settling time, and average floc size were used to evaluate the flocculability. Compared with the linear flocculant poly (acrylamide/liner-N-acryloyl-1,2-diaminoethane hydrochloride) (PAM-LADE), the novel hyperbranched polymeric flocculants exhibited outstanding flocculability which were reflected by shorter settlement time, high transmittance and large floc size. The primary cause that PAM-HADEs owned excellent flocculability is the more stretching configuration and less chains entanglement of PAM-HADEs in waste-water due to their hyperbranched structure compared with that of the linear PAM-LADE which exhibited curly coil configuration. On the other hand, abundant and exposed cationic terminal groups of PAM-HADEs originated from their hyperbranched structure also hint higher flocculation capacity. At optimum dosages of the polymer, the transmittance of the supernatant is less at low and high pH values, indicating that the natural pH (pH 7.29) of the suspension is the most appropriate pH for the flocculation. 相似文献
943.
Thomalla Frank Lebel Louis Boyland Michael Marks Danny Kimkong Ham Tan Sinh Bach Nugroho Agus 《Regional Environmental Change》2018,18(4):1211-1222
Regional Environmental Change - Most studies of major disasters focus on the impacts of the event and the short-term responses. Some evaluate the underlying causes of vulnerability, but few... 相似文献
944.
G. H. Ong C. K. Yap M. Maziah H. Suhaimi S. G. Tan 《Environmental monitoring and assessment》2013,185(4):3243-3254
The first objective of this study was to provide data of arsenic (As) levels in Peninsular Malaysia based on soil samples and accumulation of As in Centella asiatica collected from 12 sampling sites in Peninsular Malaysia. The second objective was to assess the accumulation of As in transplanted C. asiatica between control and semi-polluted or polluted sites. Four sites were selected which were UPM (clean site), Balakong (semi-polluted site), Seri Kembangan (semi-polluted site) and Juru (polluted site). The As concentrations of plant and soil samples were determined by Instrumental Neutron Activation Analysis. The As levels ranged from 9.38 to 57.05 μg/g dw in soils, 0.21 to 4.33 μg/g dw in leaves, 0.18 to 1.83 μg/g dw in stems and 1.32–20.76 μg/g dw in roots. All sampling sites had As levels exceeding the CCME guideline (12 μg/g dw) except for Kelantan, P. Pauh, and Senawang with P. Klang having the highest As in soil (57.05 μg/g dw). In C. asiatica, As accumulation was highest in roots followed by leaves and stems. When the As level in soils were higher, the uptake of As in plants would also be increased. After the transplantation of plants to semi-polluted and polluted sites for 3 weeks, all concentration factors were greater than 50 % of the initial As level. The elimination factor was around 39 % when the plants were transplanted back to the clean sites for 3 weeks. The findings of the present study indicated that the leaves, stems and roots of C. asiatica are ideal biomonitors of As contamination. The present data results the most comprehensive data obtained on As levels in Malaysia. 相似文献
945.
A comparison of radiometric correction techniques in the evaluation of the relationship between LST and NDVI in Landsat imagery 总被引:1,自引:0,他引:1
Atmospheric corrections for multi-temporal optical satellite images are necessary, especially in change detection analyses,
such as normalized difference vegetation index (NDVI) rationing. Abrupt change detection analysis using remote-sensing techniques
requires radiometric congruity and atmospheric correction to monitor terrestrial surfaces over time. Two atmospheric correction
methods were used for this study: relative radiometric normalization and the simplified method for atmospheric correction
(SMAC) in the solar spectrum. A multi-temporal data set consisting of two sets of Landsat images from the period between 1991
and 2002 of Penang Island, Malaysia, was used to compare NDVI maps, which were generated using the proposed atmospheric correction
methods. Land surface temperature (LST) was retrieved using ATCOR3_T in PCI Geomatica 10.1 image processing software. Linear
regression analysis was utilized to analyze the relationship between NDVI and LST. This study reveals that both of the proposed
atmospheric correction methods yielded high accuracy through examination of the linear correlation coefficients. To check
for the accuracy of the equation obtained through linear regression analysis for every single satellite image, 20 points were
randomly chosen. The results showed that the SMAC method yielded a constant value (in terms of error) to predict the NDVI
value from linear regression analysis-derived equation. The errors (average) from both proposed atmospheric correction methods
were less than 10%. 相似文献
946.
947.
Effects of fifteen PBDE metabolites, DE71, DE79 and TBBPA on steroidogenesis in the H295R cell line 总被引:1,自引:0,他引:1
Song R He Y Murphy MB Yeung LW Yu RM Lam MH Lam PK Hecker M Giesy JP Wu RS Zhang W Sheng G Fu J 《Chemosphere》2008,71(10):1888-1894
Polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA) are brominated flame retardants that are produced in large quantities and are commonly used in construction materials, textiles, and as polymers in electronic equipment. Environmental and human levels of PBDEs have been increasing in the past 30 years, but the toxicity of PBDEs is not fully understood. Studies on their effects are relatively limited, and show that PBDEs are neurotoxins and potential endocrine disrupters. Hydroxylated (OH) and methoxylated (MeO) PBDEs have also been reported in the adipose tissue, blood and milk of wild animals and humans. In the present study, 15 PBDE metabolites, two BDE mixtures (DE71 and DE79), and TBBPA were studied individually to determine their effects on ten steroidogenic genes, aromatase activity, and concentrations of two steroid hormones (testosterone and 17beta-estradiol) in the H295R human adrenocortical carcinoma cell line. Exposure to 0.05 microM 2'-OH-BDE-68 significantly induced the expression of CYP11A, CYP11B2, CYP17, CYP21, 3betaHSD2, 17betaHSD1, and 17betaHSD4, and the expression of StAR was induced by 6-OH-BDE-90 at the three exposure concentrations. Exposure to DE71 and DE79 resulted in dose-dependent trend towards induction, but these effects were not significant. Exposure to 0.5 microM 2-OH-BDE-123 and 2-MeO-BDE-123 resulted in significantly greater aromatase activity. However, none of the compounds affected sex hormone production at the concentrations tested. Generally, OH-BDEs had a much stronger ability to affect steroidogenic gene expression than MeO-BDEs. 相似文献
948.
Cu~(2+)改性活性炭的制备及其去除废水中CN~-的研究 总被引:1,自引:0,他引:1
以活性炭为载体负载溶液中的 Cu~(2+),Cu~(2+)改性活性炭对溶液中 CN~-的去除效果较好。Cu~(2+)改性活性炭的最佳制备条件:活性炭加入量为1 g,质量浓度为5 g/L 的 CuSO_4溶液加入量为50 mL,溶液 pH 为4,负载时间为5.0 h。在此最佳条件下活性炭的最大 Cu~(2+)负载量为25.90 mg(以每克活性炭计)。Cu~(2+)改性后活性炭的 CN~-去除率明显提高,由22.10%提高至94.07%。Cu~(2+)改性活性炭吸附CN~-的最佳实验条件:溶液 pH 为12~13,吸附时间为9 h。Cu~(2+)改性活性炭对 CN~-的饱和吸附量为22 mg/g。Mg~(2+),K~+,Ca~(2+),Cl~-,SO_4~(2-),CO_3~(2-),AsO_3~-对 Cu~(2+)改性活性炭的 CN~-去除率基本没有影响。Cu~(2+)改性活性炭的动态吸附实验表明,开始一段时间流出液中 CN~-含量几乎为零,远低于国家排放标准(0.5 mg/L)。 相似文献
949.
Raymond R. Tan Denny K.S. Ng Dominic C.Y. Foo Kathleen B. Aviso 《Process Safety and Environmental Protection》2009,87(3):197-205
This paper presents a novel superstructure-based optimization model for the synthesis of industrial water networks with partitioning regenerators. Such regenerators function by splitting a contaminated water stream into a regenerated lean stream and a low-quality reject stream. Membrane separation-based processes are examples of these types of regenerators. The optimization model presented in this work integrates a single, centralized partitioning regenerator with a source–demand superstructure under the assumption that the processes within the plant are of the fixed flow rate type. The formulation is non-linear as a result of the presence of bilinear terms in the regenerator balance equations, but global optimal solutions can be found using commercial software. The features of the model are illustrated by solving case studies from the literature. It is notable from these examples that considerable design flexibility exists in networks of this type, since potentially both the lean and reject streams from the partitioning regenerator can be reused/recycled within the plant. 相似文献
950.
超声破解吸持稠油粘土颗粒的研究 总被引:2,自引:0,他引:2
在频率为28 kHz的超声辐照下,研究了超声作用功率和辐照时间对石油污染土壤淋洗液中吸持稠油粘土颗粒的破解作用,并采用GC/MS分析了超声辐照时间对淋洗液中特征有机物的影响。结果表明,随着超声作用功率和辐照时间的增加,粘土颗粒吸持的稠油显著下降,辐照时间为45 min,作用功率为100 W时,粘土颗粒吸持稠油的解吸率为7925%;作用功率为60 W,辐照时间为75 min时,粘土颗粒吸持稠油的解吸率为77.36%。超声波能够显著增加解吸稠油在水中的溶解率,辐照时间为45 min,作用功率为80 W时,水相含油率升高92%;当作用功率为60 W,辐照时间为75 min时,水相含油率升高近1倍。随着超声辐照时间的增加,极性相对较强的环烷酮类有机物的相对丰度随之增加,极性相对较弱的环烷二酮类有机物相对丰度则显著减小。超声波有利于异位化学淋洗在高含粘土颗粒石油污染土壤修复中的应用。 相似文献