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91.
The structures of disperse dyes and their intermolecular interactions have important impacts on dyeing and printing performances for polyester fabrics. The fluorine dyes show some unique molecular stability and photochemical properties. The dyeing property of the azo dye containing trifluoromethyl group for polyester fabrics, 4'-(N-acetoxyethyl-Nethyl)- amino-2-bromine-4-nitro-6-trifluoromethylazo- benzene (D1), was investigated and compared with the similar structure disperse dye. The results show that the high color yield and good exhaustion of the dyed PET fabrics could be obtained. The polyester fabrics dyed with D1 had excellent light fastness. Its single crystal was prepared and the supramolecular interactions were solved by X-ray diffraction. Dye D1 formed triclinic crystals in a trimeric packing mode. The C-F bond distances of CF3 are 1.2730 Å, 1.2240 Å and 1.2900 Å, respectively. The two benzene rings linked azo unit (-N=N-) are obviously twist. The dihedral angle of the two benzene rings is 50.23 o. There are six weak hydrogen bonds around trifluoromethyl group in the intramolecule and intermolecule. The excellent light stability of the dye should be attributed to its unique supramolecular structure.  相似文献   
92.
Alkaline pectinase was one of the most effective enzymes to treat cotton as alternative agent to replace the conventional alkaline method. Removal of pectin and cutin was considered the explanation for improvement of wettability as well as water adsorption on cotton fiber. However, degradation kinetics of pectin is unclear, and the influence of fiber shape on property changes after enzymatic treatment was ignored. The main objective of this work was to reveal interactions between pectinase and cotton fiber for mechanism study. A heterogeneous catalysis kinetic equation, which is associated with Langmuir adsorption model and enzyme deactivation, was used to describe the heterogeneous catalysis. The enzymatic process conditions were optimized. Raw cotton fibers, pectinase-treated and alkali-treated fibers were characterized by impurities content determination, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Mechanism of water adsorption enhancement on treated fibers was discussed. In addition to elimination of the outer impurities, flat fibers with less twist and shape changes of lumen were also obtained to ensure better accessibility and water adsorption after enzymatic treatment.  相似文献   
93.
Pacific abalone Haliotis discus hannai (Haliotidae, Gastropoda) is an economically important shellfish species in northern China. The complete nuclear ribosomal DNA (nrDNA) of Pacific abalone was amplified, sequenced, and analyzed. The length of the nrDNA was determined to be around 10.7 kb, and to contain, in order, small subunit ribosomal RNA (nrSSU) genes (1871 bp), internal transcribed spacer (ITS, 759–762 bp), large subunit ribosomal RNA (nrLSU) gene (3411 bp), and an intergenic spacer (IGS, 4624–4654 bp). The SSU and LSU regions were almost identical in different individuals, and show little variation from those of other abalone species. The two different variations of the ITS2 region were presented, and this phenomenon also existed in other species. A phylogeny tree was constructed, based on ITS region sequence datasets, to determine the evolutionary relationships of abalones. Abalones have two major subclades, mainly distributed in the North Pacific, Europe and Australia. The IGS region of the nrDNA was sequenced and analyzed for the first time. Several repeat fragments were present upstream of the sequence, and were significantly different between individuals (93.86% sequence identity). The complete nrDNA sequence will be useful for the classification, identification, phylogeny, germplasm management, and breeding of this shellfish.  相似文献   
94.
In this study, two experiments were performed to explore the function of silymarin in adipogenesis in grass carp (Ctenopharyngodon idellus) using in vitro and in vivo models. In experiment 1, differentiated grass carp pre-adipocytes were treated with silymarin for 6 days. Treatment with 100 μg mL?1silymarin (SM100 group) significantly reduced triglyceride accumulation at day 6. The adipogenic gene expression levels of PPARγ, C/EBPα, SREBP1c, FAS, SCD1, and LPL, and the protein expression level of PPARγ were significantly down-regulated in the SM100 group. Additionally, the SM100 group had significantly lower reactive oxygen species production and reduced glutathione contents compared with the control in vitro. In experiment 2, the juvenile grass carp (mean body weight= 27.4 ± 0.17 g) were fed six isonitrogenous and isocaloric diets in a factorial design containing 0, 100, or 200 mg kg?1 silymarin (SM0, SM100, SM200) associated with either 4 or 8% lipid levels (low lipid, LL, and high lipid, HL, respectively) for 82 days. The results demonstrated that dietary silymarin supplementation significantly reduced the elevated intraperitoneal fat index in grass carp fed with high-lipid diets, and the gene expression of adipogenesis (PPARγ, FAS) when supplemented with dietary silymarin was notably lower than when no silymarin was supplemented under the high-lipid diets. Thus, our data suggest that silymarin suppressed lipid accumulation in grass carp both in vitro and in vivo, and the effect might be due to an influence on the expression of adipogenesis factors and ROS production partly associated with effects on antioxidant capability.  相似文献   
95.
In vertebrates, thyroid hormone receptors (TRs) and deiodinases are essential for developmental events driven by the thyroid hormones (THs). However, the significance of deiodinases during the metamorphosis of the Japanese flounder (Paralichthys olivaceus) remains unclear. Moreover, regulation and response of the TRs and deiodinases to THs in this fish are poorly understood. Therefore, we detected the expression patterns of THs, deiodinases, and TRs in drug-treated larvae and untreated larvae of P. olivaceus by using enzyme-linked immunosorbent assay and quantitative real-time PCR during P. olivaceus metamorphosis. To further understand the roles of these elements, a rescue assay was performed. Our results show the importance of THs, TRs, and deiodinases in flatfish metamorphosis. Our results also confirm that D1 and D2 activate THs and D3 plays the opposite and complementary role. Moreover, we demonstrated that both TRα and TRβ have important but different roles during P. olivaceus metamorphosis.  相似文献   
96.
Silk is very promising in the field of biomaterials as a natural biomacromolecule. Silk protein can be made into various forms of materials, including hydrogels. However, silk protein-based hydrogels have not attracted much attention due to its weak mechanical properties. Here, we report high water content silk protein-based hydrogels with tunable elasticity which were fabricated through Ru(II) mediated photochemically cross-linking tyrosine residues in regenerated silk protein. The regenerated silk protein was characterized by Fourier transform infrared spectroscopy (FTIR). The gelation kinetics of the silk protein was studied by rheology measurements. The compressive mechanical properties of the silk protein-based hydrogels was investigated using compressive tests and dynamic mechanical analysis (DMA). Compressive modulus of the hydrogels reached 349±64 MPa at 15 % strain. The fabricated silk protein-based hydrogels were also characterized by Scanning electron microscopy (SEM), revealing an interconnected porous network structure, typical of hydrogels, with an average pore size of approximately 130 μm. Finally, biocompatibility of the silk protein-based hydrogels was demonstrated through cell culture studies using a human fibroblast cell line, HFL1. The reported silk protein-based hydrogels represent a promising candidate for biomaterial applications.  相似文献   
97.
Paddy fields are subjected to fluctuating water regimes as a result of the alternate drying and wetting water management, which often incurs a sensitive change in N2O emissions from paddy soils. However, how the soil moisture regulates the emission of N2O from paddy soil remains uncertain. In this study, three incubation experiments were designed to study the effects of constant and fluctuating soil moisture on N2O emission and the sources of N2O emission from paddy soil. Results showed that the N2O emission from paddy soil at 100 % WHC (water-holding capacity) was higher than that at 40, 65, 80, 120, and 160 % WHC, indicating that 100 % WHC was the optimum soil moisture content for N2O emission under the incubation experiment. Small peak of N2O flux appeared when the soil moisture content from 250 % WHC decreased near to 100 % WHC, lower than that triggered by nitrogen (N) fertilization, which was mainly owing to the low NH4 + concentration at this period. Nitrification dominated the emissions of N2O from paddy soil at 250 % WHC (54.96 %), higher than that of nitrification-coupled denitrification (6.74 %) and denitrification (38.3 %). The contribution of denitrification to N2O emissions (44.10 %) was equivalent to that of nitrification (44.45 %) in soil at 100 % WHC, which was higher than that of 250 % WHC treatment. In conclusion, the finding suggested that the peak of N2O in paddy soils during midseason aeration could be attributed to the occurrence of optimum soil moisture under sufficient N availability, favorable for the production and accumulation of N2O.  相似文献   
98.

Background

High latitude ecosystems are at present changing rapidly under the influence of climate warming, and specialized Arctic species at the southern margin of the Arctic may be particularly affected. The Arctic fox (Vulpes lagopus), a small mammalian predator endemic to northern tundra areas, is able to exploit different resources in the context of varying tundra ecosystems. Although generally widespread, it is critically endangered in subarctic Fennoscandia, where a fading out of the characteristic lemming cycles and competition with abundant red foxes have been identified as main threats. We studied an Arctic fox population at the Erkuta Tundra Monitoring site in low Arctic Yamal (Russia) during 10 years in order to determine which resources support the breeding activity in this population. In the study area, lemmings have been rare during the last 15 years and red foxes are nearly absent, creating an interesting contrast to the situation in Fennoscandia.

Results

Arctic fox was breeding in nine of the 10 years of the study. The number of active dens was on average 2.6 (range 0–6) per 100 km2 and increased with small rodent abundance. It was also higher after winters with many reindeer carcasses, which occurred when mortality was unusually high due to icy pastures following rain-on-snow events. Average litter size was 5.2 (SD = 2.1). Scat dissection suggested that small rodents (mostly Microtus spp.) were the most important prey category. Prey remains observed at dens show that birds, notably waterfowl, were also an important resource in summer.

Conclusions

The Arctic fox in southern Yamal, which is part of a species-rich low Arctic food web, seems at present able to cope with a state shift of the small rodent community from high amplitude cyclicity with lemming dominated peaks, to a vole community with low amplitude fluctuations. The estimated breeding parameters characterized the population as intermediate between the lemming fox and the coastal fox ecotype. Only continued ecosystem-based monitoring will reveal their fate in a changing tundra ecosystem.
  相似文献   
99.
The birds of Kabakl? Pond and its near surrounding were surveyed between October 2014 and December 2015 periods. During the study period, 105 bird species that belong to 12 orders and 34 families were detected and represented. Among these species determined, 17 of them certainly, 19 probably and 11 possibly breed in the area, while 58 of them are wintering or transitory migrating birds for the area. Among the recorded species, seven are globally threatened, while 20 are threatened for Turkey without least concern species. Obtained information suggests that this small artificial area has a great importance for many bird species related to habitat that have. Habitat preferences of species were analysed, and it was determined that the most preferred habitats are pond (water surface), wooded and agricultural zones, respectively. Also, the maximum bird number obtained during April and December, while maximum bird species richness observed during April. Results suggest that artificial ponds can be important for birds as feeding, resting and breeding area due to rapidly decline in natural wetland areas. Effective protection of the area requires the prevention of illegal hunting, fishing, human disturbance and pasturing. Also, in order to extend the existing reed and meadow areas, convenient plantation of natural plants at around of pond has a critic role for waterfowl.  相似文献   
100.
Use of nutrient efficient crop species or cultivars within species in combination with improved crop production practices offer the best option for meeting the future food requirements of growing world populations. Efficiency improvement has a key role for nutrient use and it improves both productivity of yield and minimizes risks of losses that potentially harm the environment. To improve nutrient use efficiency (NUE), one strategy is to select cultivars of crops with high NUE. Both nitrogen (N) and phosphorus (P) are among essential macronutrients commonly applied to agricultural crops to optimize yields. Evaluation of potato cultivars with high N and P efficiency is essential for sustainable production of the crop. In Ethiopia, however, little research has been done to elucidate better NUE of potato crop until recently. This study was, thus, designed to evaluate selected potato cultivars (Belete, Gudene, Jalene, Marachere and one local check) for NP use efficiency under low levels of the nutrients in Wolaita Sodo University, Ethiopia during 2014 and 2015. Factorial combination of 3 levels of each N (0, 55.5 and 111 kg N ha?1 ) and P (0, 19.5 and 39 kg P ha?1 ) were assigned to the main plots and the 5 cultivars to subplots of split-plot design in three replications. Efficiency indices such as agronomic efficiency, physiological efficiency and recovery efficiency were computed for combined NP nutrients. Results showed that agronomic nitrogen use efficiency, apparent phosphorus use efficiency and phosphorus use efficiencies were significantly influenced by the interaction effect of rates of NP nutrition and variety. Application of NP more than 55.5:19.5 kg ha?1 will not beneficial due to their less or equal use and recovery efficiencies to 55.5:19.5 kg NP ha?1. Belete was the most NP efficient variety followed by Jalene and Gudene in all efficiency indices. Therefore, Belete, Jalene and Gudene return better for NP at 55.5:19.5 kg ha?1 for economical use of fertilizes while obtaining satisfactory yield. It can be concluded that yield response variation of the varieties was related to their differences in NP uptake and use efficiencies; and the improved potato varieties were superior to local check in using NP nutrients efficiently.  相似文献   
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