Thermally Switchable Periodicities and Diffraction from Mesoscopically Ordered Materials     

JM Weissman  HB Sunkara  AS Tse  SA Asher 《Science (New York, N.Y.)》1996,274(5289):959-960

Two switchable, mesoscopically periodic materials were created by combining crystalline colloidal array (CCA) self-assembly with the temperature-induced volume phase transition of poly(N-isopropylacrylamide) (PNIPAM). Body-centered-cubic CCAs of hydrated, swollen PNIPAM particles Bragg-diffract infrared, visible, and ultraviolet light weakly, whereas arrays of compact shrunken particles diffract efficiently. A tunable diffracting array was also created by embedding a CCA of polystyrene spheres within a PNIPAM hydrogel that swells and contracts with temperature; thus the array lattice constant varies with temperature, and the diffracted wavelength was thermally tunable across the entire visible spectrum. These materials may find applications in many areas of optics and materials science.  相似文献   

Clinical trial of efficacy of ivermectin pour‐on against gastrointestinal parasitic nematodes in silvopasturing horses     

I. FRANCISCO  J. A. SÁNCHEZ  F. J. CORTIÑAS  R. FRANCISCO  E. MOCHALES  M. ARIAS  P. MULA  J. L. SUÁREZ  P. MORRONDO  P. DÍEZ‐BAÑOS  R. SÁNCHEZ‐ANDRADE  A. PAZ‐SILVA 《Equine veterinary journal》2009,41(7):713-715

The aim of this study was to assess, by a clinical trial, the efficacy of an ivermectin‐based pour‐on treatment against gastrointestinal parasitic nematodes in naturally infected horses using 2 groups of mature indigenous Pura Raza Galega grazing mares. Faecal and blood samples were collected individually over a 21 week period. Faeces were analysed by the coprological flotation, sedimentation and migration techniques. Changes in circulating blood cells were monitored over the study period. The administration of the ivermectin suppressed the eggelimination of ascarids and pinworms throughout the study and no strongyle‐eggs were observed in the treatment group between the 3rd and 10th weeks. The numbers of red cells increased significantly after the anthelmintic therapy, and a statistical reduction in circulating leucocytes was recorded. No side effects were observed. The pour‐on ivermectin formulation was highly successful against gastrointestinal nematodes and appears to be a useful therapeutic routine for large groups of horses.  相似文献   

Non‐gelatinized starch influences the deposition of n‐3 fatty acids in the muscle of a tropical freshwater fish,Labeo rohita     

V. Kumar  N. P. Sahu  A. K. Pal  S. Kumar  P. Sharma  J. K. Chettri  A. K. Sinha 《Journal of animal physiology and animal nutrition》2009,93(5):659-668

A 60‐day feeding trial was conducted to study the influence of gelatinized (G) to non‐gelatinized (NG) starch ratio in the diet on fatty acids profiles and oxidative status in Labeo rohita fingerlings. Two hundred and thirty‐four fingerlings (average weight: 2.53 g) were distributed in six treatment groups with each of three replicates. Six semi‐purified diets either containing NG and/or G corn starch (42.43%) viz., T₁ (100% NG and 0% G starch), T₂ (80% NG and 20% G starch), T₃ (60% NG and 40% G starch), T₄ (40% NG and 60% G starch), T₅ (20% NG and 80% G starch) and T₆ (0% NG and 100% G starch) was fed to respective groups. Catalase, superoxide dismutase and malic enzyme activities decreased linearly with the increasing level of G starch, whereas reverse trend was found for glucose‐6‐phosphate dehydrogenase. Total saturated fatty acids in muscle increased with the increasing level of G starch in the diet. Total n‐3 fatty acids decreased linearly with the increasing level of G starch in the diet. Among the n‐3 fatty acids, linolenic acids content was more in NG starch fed group. Similarly, eicosapentaenoic acid contents gradually decreased with increasing level of G starch content. The n‐6/n‐3 ratio was higher in G starch fed group. This suggests that dietary starch type may be manipulated for quality improvement of fish flesh.  相似文献   

Study of changes in some pathophysiological stress markers in different age groups of an animal model of acute and chronic heat stress   总被引：2，自引：0，他引：2  

Sinha RK 《Iranian Biomedical Journal》2007,11(2):101-111

BACKGROUND: This study demonstrates the changes in six different pathophysiological parameters such as body weight, body temperature, fecal pellet count, blood-brain barrier (BBB) permeability, plasma corticosterone level and emergence of hemorrhagic peptic ulcer spots due to exposure to high environmental heat in three different age groups of freely moving rats. METHODS: Each age group of rats was sub divided into three groups: (i) acute heat stress-subjected to a single exposure for four hours in the Biological Oxygen Demand incubator at 38 degrees C; (ii) chronic heat stress-exposed for 21 days daily for one hour in the incubator at 38 degrees C, and (iii) handling control groups. The data were recorded for the analyses of the changes in different parameters just after the heat exposure from acute stressed rats and on 1st, 3rd, 6th, 9th, 12th, 15th, 18th and 21st day on chronic stressed rats for body temperature, body weight, fecal pellets count. For the analysis of changes in three other parameters, BBB permeability, plasma corticosterone level and peptic ulcer spots following chronic exposure to high environmental heat, data were recorded on 22nd day for the analysis. RESULTS: Analysis of variance (ANOVA-1) of the observations demonstrates a significant increase in body temperature, fecal pellet count, BBB permeability (except in adult group), plasma corticosterone level and emergence of hemorrhagic peptic ulcer spots in all three different age group of rats due to exposure to acute heat stress. However, chronic heat was found responsible for the significant reduction in body weight in weaning and young rats, increase in body temperature, number of fecal pellets excreted (in early days of chronic stress) and number of peptic ulcer spots in all three age groups of rats. At the same time, BBB extravasations were not observed in rats except very mild in weaning group. CONCLUSION: The results of the present study indicate that the acute as well as chronic exposure to hot environment significantly alters the physiology of different organs of the body.  相似文献   

Indicators of soil quality and crop productivity assessment at a long-term experiment site in the lower Indo-Gangetic plains     

Partha Sarathi Ghorai  Sunanda Biswas  Tapan Jyoti Purakayastha  Nayan Ahmed  Tapas Kumar Das  Radha Prasanna  Bharat Hanamant Gawade  Kallol Bhattacharyya  Kanchan Sinha  Priya Singh  Sujit Das 《Soil Use and Management》2023,39(1):503-520

Deterioration of soil quality under resource-intensive modern agriculture in the face of global climate change poses a huge risk to food security. Because of the complex nature, estimators of soil quality often rely upon a limited set of soil attributes, along with statistical data reduction techniques, for developing quality indices, whilst overlooking biological aspects and regional climatic variability. This study screened the most suitable soil quality indexing approaches for a rice-oilseed-based cropping system in the lower Indo-Gangetic plains (IGP). For this, surface soil samples (0–15 cm) were collected from an ongoing long-term fertilizer experiment with a rice-mustard-sesame cropping system in the IGP. The following treatments were assessed for their effect on soil quality: T₁-control, T₂-NPK (recommended NPK doses), T₃-NPKG (NPK + in situ green manuring), T₄-NPKGB (NPK + in situ green manuring + biofertilizer) and T₅-NPKF (NPK + farm yard manure FYM). We found that total organic carbon (TOC), β-glucosidase, CaCl₂ extractable S, alkaline KMnO₄ oxidizable N, activity of urease, amidase enzyme and mean weight diameter (MWD) were sensitive key indicators of soil quality. The NPKF treatment maintained the highest soil quality status (0.80–0.91), both under productivity and environmental protection goals, owing to the availability of decomposable carbon. Regression analysis showed a better agreement of equivalent rice yield with expert opinion (EO; R² = 0.89) than principal component analysis (PCA; R² = 0.76). Finally, we found that the expert opinion approach with the nonlinear scoring function was the best tool for soil quality assessment of the region.  相似文献