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41.
From early times, jute fibre has been generally conditioned for easy spinning by adding oil and water in the form of an emulsion. The commonly used oil consists of C12–C31 fractions of mineral oil that sometimes impart different intensities of oily (kerosene) or fishy smell to the end product. In the present work, efforts have been made to find a suitable sustainable substitute of mineral oil based conditioning agent for spinning of jute yarn and for this, three types of vegetable oil (rice bran oil, palmolein oil and castor oil), a silicone emulsion, a mixed enzyme system and glycerine have been used separately or in combinations as conditioning agents for jute fibre before its mechanical processing for making yarn in jute spinning machines. Considering comparable mechanical process performance for spinning of jute fibre (viz., fibre loss as droppings during processing, moisture retention prior to spinning stage and spinning end breakage rate), tensile properties of yarn, and lower yarn hairiness, it may be suggested to use 2.5% castor oil alone, or 2% castor oil in combination with 0.1–0.5% glycerine in the form of oil-in-water emulsion as the most suitable alternatives to conventional mineral oil-based jute conditioning agent to spin ordinary jute yarn. 相似文献
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43.
Footrot is a highly contagious disease of the feet of ruminants caused by the synergistic action of certain bacterial species of which Dichelobacter nodosus (D. nodosus) is the main transmitting agent. The infection is specific to sheep and goats, although it has also been reported in cattle, horses, pigs, deer and mouflon. The antigenic diversity of D. nodosus is due to variations in the DNA sequence of its fimbrial subunit gene (fimA) and provides the basis for classification of the organism into at least 10 major serogroups (A-I and M), the distribution of which varies with different geographical locations. Host immune response to vaccination is serogroup specific. There are three different clinical forms of disease caused by virulent, intermediate and benign strains of D. nodosus, respectively. In order to facilitate rapid and reliable clinical diagnosis, virulence determination, strain differentiation and serogroup identification for effective control measures, immunological tests, DNA probes and PCR based techniques have been introduced. This review summarises the current understanding of the mechanisms of antigenic diversity of D. nodosus as well as advances made in its strain differentiation and diagnosis. 相似文献
44.
Nicola Mori Francesco Pavan Nazareno Reggiani Mirko Bacchiavini Luca Mazzon Samanta Paltrinieri Assunta Bertaccini 《Journal of pest science》2012,85(1):23-28
The phytoplasmas associated with bois noir (BN) tuf-type a are transmitted to grapevines by means of Hyalesthes obsoletus Signoret using Urtica dioica L. as the inoculum source. In the period 2003–2008, a research was carried out in six vineyards of northern Italy where a
large amount of nettles in the ditches surrounding vineyards was detected. The aim was to establish the nettle control effects
on the presence of H. obsoletus and new symptomatic grapevines. PCR and RFLP analyses showed the presence of the BN tuf-type a phytoplasmas in symptomatic
grapevines of all vineyards and in the vector. Weed control strategies along ditches were always associated with decreases
in nettle coverage and H. obsoletus numbers. A reduction in the percentage of new symptomatic grapevines occurred in all vineyards except for one vineyard where
the least reduction in nettle and H. obsoletus was observed. The decrease in H. obsoletus population was significantly correlated with a decrease in nettles along ditches, and the reduction in H. obsoletus population was correlated with a decrease in incidence of new symptomatic grapevines compared with the incidence before the
application of weed control measures. Nettle weeding can reduce the incidence of BN tuf-type a, but weed control costs and
impacts need to be considered. 相似文献
45.
Lolium multiflorum Lam. is an annual weed that has developed resistance to diclofop-methyl herbicide. Knowledge of the relative fitness components of resistant and susceptible biotypes is important to predict and manage resistance. Here, we use different L. multiflorum selections obtained from a long-term experiment, in which the herbicide dose (0, 280, 560 and 1120 g a.i. ha−1) and gene flow chances from Festuca rubra, naturally resistant to the herbicide, were managed. The relationship among herbicide selection history, the level of resistance achieved, and seed dormancy, germination rate and ageing is evaluated. The current resistance level of the different selections was not related to the herbicide dose of selection. The level of association between herbicide resistance and germination varied with the selection treatment and after-ripening time. There was a general positive relationship between hours to 50% germination and herbicide dose of selection, which was independent from the presence of F. rubra. Two L. multiflorum selections with highest resistance level diverged in their response to alternating temperature (i.e. seed dormancy level). While one of them displayed a high germination rate and high ageing rate, the second one displayed a low ageing rate during the evaluated period, similar to the control selection. Most arguments on how weeds evolve increasing fitness on agricultural fields are centered on dose responses and rarely on the effects of herbicide selection on other traits. Our results provide evidence that directional selection for other characteristics apart from resistance, may result from herbicide control causing adaptive phenological change. 相似文献
46.
Antistatic effect of atmospheric pressure glow discharge cold plasma treatment on textile substrates
Hydrophobic synthetic textile substrates, nylon and polyester fabrics, were continuously treated in an atmospheric-pressure-glow-discharge-cold-plasma
reactor using He and air. The samples were evaluated for antistatic properties by measuring the static charge build-up and
half charge decay time. The 60 sec air-plasma treated nylon fabric produced only 1.53 kV of charge and showed a significantly
smaller half decay time of 0.63 sec compared to static voltage of 2.76 kV and a half decay time of 8.9 sec in the untreated
nylon fabric. In comparison, the He plasma treated nylon fabrics showed relatively less improvement by producing static charge
built-up of 2.12 kV and half charge decay time of 1.1 sec. Similar improvements were obtained for polyester (PET) fabrics
as well. The treated samples showed good antistatic properties even after five laundry wash cycles. The surface characteristics
of the samples were investigated using SEM, AFM, and ATR-FTIR. The results revealed that the improvement on antistatic properties
are attributable to increase in the surface energy of the fabrics due to the formation of hydrophilic groups and increase
in the surface area due to the formation of nano-sized horizontal and vertical channels on the fibre surface. The study suggests
that plasma treatment may be used for imparting effective antistatic finish on otherwise hydrophobic substrates. 相似文献
47.
Effects of systemic fungal endophytes on the performance of meadow fescue and tall fescue in mixtures with red clover 下载免费PDF全文
S. Dirihan M. L. Helander I. Saloniemi P. E. Gundel K. Saikkonen 《Grass and Forage Science》2015,70(3):465-473
A symbiosis between grasses and systemic fungal endophytes exists in both natural and agricultural grassland communities. Our objective was to examine the effects of systemic endophytes on the competitive ability of two agronomically important grass species: meadow fescue [Festuca pratensis (Huds.) syn. Schedonorus pratensis (Huds.) P. Beauv] and tall fescue [Festuca arundinacea (Schreb.) syn. Schedonorus phoenix (Scop.)]. Plants of meadow and tall fescue were grown for 48 days in replacement series of interspecific mixture with a legume (red clover, Trifolium pratense L.) in different nutrient environments in a greenhouse. Neither of the grass species gained endophyte‐promoted competitive advantage over red clover in grass–clover mixtures. Endophyte infection increased the growth of meadow fescue monocultures by 89% compared to endophyte‐free monocultures in high‐nutrient soils, but plant competition or the cost of endophyte infection to the meadow fescue decreased the yield in resource‐limited conditions. On average, endophyte‐infected and endophyte‐free meadow fescues produced 0·15 and 0·17 g, and 0·14 and 0·14 g dry biomass per plant in mixtures with red clover in high‐ and low‐nutrient soils respectively. In contrast to meadow fescue, endophyte‐promoted growth of tall fescue monocultures was not detected. Endophyte‐infected and endophyte‐free tall fescue monocultures produced 0·76 and 0·95 g biomass per pot, respectively, in the high‐nutrient environment. Endophyte infection can increase the performance of the host grass, but the positive effects depend on the host species, the species composition and soil nutrient availability. 相似文献
48.
Bandyopadhyay S Lodh C Rahaman H Bhattacharya D Bera AK Ahmed FA Mahanti A Samanta I Mondal DK Bandyopadhyay S Sarkar S Dutta TK Maity S Paul V Ghosh MK Sarkar M Baruah KK 《Research in veterinary science》2012,93(2):604-610
Thirty-one shiga toxin-producing (STEC) and 6 enteropathogenic Escherichia coli (EPEC) were isolated from 87 raw yak milk and 63 'churpi' samples. Of 18 stx(1) positive isolates (48.6%), 14 carried stx(1c) (77.7%). Subtyping of 28 stx(2) positive isolates (75.7%) revealed the presence of stx(2c) (9, 32.1%), stx(2d) (3, 10.7%), stx(2e) (1, 3.57%) and stx(2f) (3, 10.7%) variants. Furthermore, intimin (eaeA), enterohaemolysin (ehxA), autoagglutinating adhesin (saa), iha (adherence conferring protein), efa1 (EHEC factor for adherence), bundle forming pilli (bfpA) and toxB (type III secreted protein encoded on LEE Island, similar to toxin B of Clostridium difficile) genes were detected in 14, 16, 12, 4, 3, 2 and 2 isolates, respectively. Univariate and multivariate analysis depicted that both stx(1) and stx(2) or their variants were more likely to occur in isolates from Arunachal Pradesh (p<0.04) rather than Sikkim. Dendogram constructed on the basis of RAPD and ERIC PCR profile distributed the STEC and EPEC isolates in separate clusters irrespective of their sources and serotypes. The STEC and EPEC isolates exhibited resistance against erythromycin, amikacin, azithromycin, amoxicillin, ampicillin+cloxacillin, cephalothin, furazolidone, gentamicin, kanamycin, streptomycin and tetracycline. This is the first ever report on occurrence and characterization of STEC and EPEC isolated from yak milk and milk products. 相似文献
49.
This study concerned the minimum and optimum effective doses of calcium chloride needed for induction of chemosterilization in male albino rats, 30 days after a single intratesticular injection of calcium chloride (CaCl2.2H2O) solution at 2.5, 5, 10 or 20 mg per 100 g body weight per testis. There was a significant diminution in the relative wet weight of the sex organs (p<0.01), epididymal sperm count (p<0.001), plasma concentration of testosterone (p<0.01), testicular activities of D,3-hydroxy steroid dehydrogenase (D,3-HSD), 17-hydroxy steroid dehydrogenase (17-HSD) (p<0.01), glutathione S-transferase (GST) (p<0.01), superoxide dismutase (SOD) (p<0.01), and peroxidase (p<0.01), significant elevations in testicular content of malondialdehyde (MDA) and conjugated dienes (p<0.01), along with derangement of seminiferous tubular architecture and degeneration of the Leydig cells in the testis and elevations in the concentrations in the plasma of LH and FSH (p<0.01), commencing at a dose of 5 mg, with the greatest effects at a dose of 20 mg. No significant alterations in these factors occurred at the dose of 2.5 mg in comparison to the control that received only the vehicle. There was no significant alteration in the plasma concentrations of prolactin (p>0.05), corticosterone (p>0.05) or fasting blood glucose or in the rectal temperature (p>0.05) at any of the doses relative to the control group, suggesting that this chemosterilizing procedure did not exert any chronic stress on the experimental animals. From these observations, it may be suggested that 5 mg should be considered as the minimum dose, and 10 mg or 20 mg as the optimum dose, whereas 2.5 mg was ineffective for induction of chemosterilization. There would seem to be little point in using more than 20 mg of calcium chloride for this purpose. Intratesticular injection of calcium chloride at an effective dose may be considered as an alternative to surgical castration. 相似文献
50.
L Hoffmann R Schiemann A Angelov M Djarova J Gundel W Jentsch V I Lepnova E A Machaev V Prokop K Simecek 《Archives of Animal Nutrition》1983,33(7-8):649-661
Institutes from 5 CMEA countries took part in complementary joint investigations in order to ascertain the variance in energy and protein requirement and parameters of nutrient and energy metabolism with such fattening pigs as test animals as characterise the prospective breeding development in each of the countries and in order to establish the bases for the critical revision of the norms of energy and protein requirement for fattening pigs and, if necessary, their more precise determination. The most important conclusion drawn from the comparative assessment of the results presented in 9 articles is that due to wide variations in the energy and protein requirement values between the individual investigators as well as within the institutions themselves, norms of energy and protein requirement for fattening can only be adopted between countries when adequate investigations under the specific conditions of the individual countries justify this. 相似文献