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61.
Paul M. Bond 《Pest management science》1994,41(4):369-374
In the mid- to late 1980s, supercritical fluid chromatography (SFC) was ‘reborn’ as a technique for the 1990s. Supercritical fluids have physical properties (viscosity, diffusivity and density) intermediate between those of licuids and gases. Analyte solubilities are similar to those in some liquid chromatography solvents and the gas-like properties of supercritical fluids make higher resolution or shorter analysis times possible. Applications and experience with a home-built SFC system, as well as methods developed elsewhere, are described. The successes and limitations of the technique are reviewed together with details of the instrumentation. Areas in which SFC may become the procedure of choice include multi-residue methods, non-polar analyses, micro-preparative uses and for difficult extractions. The advances in GC and HPLC technology, however, lead us to believe that SFC will remain a specialist technique, appealing only to a minority of analysts. 相似文献
62.
Harms PA Sorden SD Halbur PG Bolin SR Lager KM Morozov I Paul PS 《Veterinary pathology》2001,38(5):528-539
Three-week-old cesarean-derived colostrum-deprived (CD/CD) pigs were inoculated with porcine circovirus type 2 (PCV2, n = 19), porcine reproductive and respiratory syndrome virus (PRRSV, n = 13), concurrent PCV2 and PRRSV (PCV2/PRRSV, n = 17), or a sham inoculum (n = 12) to compare the independent and combined effects of these agents. Necropsies were performed at 7, 10, 14, 21, 35, and 49 days postinoculation (dpi) or when pigs became moribund. By 10 dpi, PCV2/PRRSV-inoculated pigs had severe dyspnea, lethargy, and occasional icterus; after 10 dpi, mortality in this group was 10/11 (91%), and all PCV2/ PRRSV-inoculated pigs were dead by 20 dpi. PCV2-inoculated pigs developed lethargy and sporadic icterus, and 8/19 (42%) developed exudative epidermitis; mortality was 5/19 (26%). PRRSV-inoculated pigs developed dyspnea and mild lethargy that resolved by 28 dpi. Microscopic lesions consistent with postweaning multisystemic wasting syndrome (PMWS) were present in both PCV2- and PCV2/PRRSV-inoculated pigs and included lymphoid depletion, necrotizing hepatitis, mild necrotizing bronchiolitis, and infiltrates of macrophages that occasionally contained basophilic intracytoplasmic inclusion bodies in lymphoid and other tissues. PCV2/ PRRSV-inoculated pigs also had severe proliferative interstitial pneumonia and more consistent hepatic lesions. The most severe lesions contained the greatest number of PCV2 antigen-containing cells. PRRSV-inoculated pigs had moderate proliferative interstitial pneumonia but did not develop bronchiolar or hepatic lesions or lymphoid depletion. All groups remained seronegative to porcine parvovirus. The results indicate that 1) PCV2 coinfection increases the severity of PRRSV-induced interstitial pneumonia in CD/CD pigs and 2) PCV2 but not PRRSV induces the lymphoid depletion, granulomatous inflammation, and necrotizing hepatitis characteristic of PMWS. 相似文献
63.
S.R. Isberg P.C. Thomson F.W. Nicholas S.G. Barker & C. Moran 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2005,122(6):370-377
Crocodile morphometric (head, snout‐vent and total length) measurements were recorded at three stages during the production chain: hatching, inventory [average age (±SE) is 265.1 ± 0.4 days] and slaughter (average age is 1037.8 ± 0.4 days). Crocodile skins are used for the manufacture of exclusive leather products, with the most common‐sized skin sold having 35–45 cm in belly width. One of the breeding objectives for inclusion into a multitrait genetic improvement programme for saltwater crocodiles is the time taken for a juvenile to reach this size or age at slaughter. A multivariate restricted maximum likelihood analysis provided (co)variance components for estimating the first published genetic parameter estimates for these traits. Heritability (±SE) estimates for the traits hatchling snout‐vent length, inventory head length and age at slaughter were 0.60 (0.15), 0.59 (0.12) and 0.40 (0.10) respectively. There were strong negative genetic (?0.81 ± 0.08) and phenotypic (?0.82 ± 0.02) correlations between age at slaughter and inventory head length. 相似文献
64.
Carla M K Morrow Victor E Valli Petra A Volmer Paul A Eubig 《Journal of veterinary diagnostic investigation》2005,17(3):223-231
Ten dogs suffered acute renal failure after ingesting > or = 3 g/kg (dry matter) of grapes or raisins. All dogs had degeneration or necrosis (or both) of proximal renal tubules with basement membranes remaining intact, and epithelial regeneration was observed in 5 out of 10 cases. Mineralized tubular debris or granular to proteinaceous casts (or both) were present in all cases. A golden-brown, globular, intracellular pigment of varying amounts and sizes was observed in 6 out of 10 cases with variable reaction with Prussian blue. Multifocal fibrinous arteritis of the large colon was seen in 2 out of 5 cases with globulin insudation of vessel wall demonstrated by immunohistochemical staining for immunoglobulin (Ig)G and IgM. Mineral analysis on frozen renal tissue from 2 out of 2 cases revealed mildly elevated Ca:P ratio in both. Clinically significant observations were preservation of the integrity of basement membranes after grape-induced tubular injury and presence of early epithelial regeneration. Thus, recovery may be possible if anuria is aggressively managed. With respect to potential pathophysiologic mechanisms, further research into the roles of calcium homeostasis, vascular reactivity, and the significance of the golden-brown pigment is indicated. 相似文献
65.
Shmuel Moran 《Pest management science》2001,57(3):248-252
Two methyl anthranilate formulations, ReJex‐iT® TP‐40 and AG‐36, were tested as bird‐repelling agents for animal feed and vegetable sprouts, respectively. Feral pigeons (Columba livia) and house sparrows (Passer domesticus) are important pests of animal husbandry and field crops in Israel. In each 4‐day experiment, four birds were held together in an aviary, and were offered four trays or dishes with animal feed or cauliflower sprouts in four corners of the cage. The trays and dishes were transposed daily in a Latin square sequence. Pigeons consumed significantly more untreated feed than treated feed. When no alternative untreated food was offered, there was no significant repellency. Treatment of animal feed with TP‐40 to give 2.0 ml methyl anthranilate kg?1 or less had no repellent effect on sparrows. Concentrations of 4.0 ml kg?1 or more repelled the sparrows significantly. When no untreated feed was presented, pigeons and sparrows preferred the lowest concentration of methyl anthranilate presented. When AG‐36 was tested on vegetable sprouts, the sparrows tended significantly to avoid the highest concentration used—14.5 ml methyl anthranilate litre?1 spray. The inter‐specific differences between the birds indicate that the efficacy of methyl anthranilate formulations as a repellent has to be specified for every species. This study did not determine (1) the possibility of developing habituation, (2) the behaviour of birds under natural conditions in the field, or (3) the influence of the feeding behaviour of a sympatric bird species on the repellency of methyl anthranilate to other species. © 2001 Society of Chemical Industry 相似文献
66.
The Rose Bengal sensitised photo-oxidation of bioresmethrin (I), 2-benzylfuran-4-ylmethyl acetate (II), and 2-benzylfuran-4-ylmethanol (III) has been studied in methanol and methanol + water (1 + 1 by volume) solutions by monitoring the rate or oxygen removal from the system. The results indicate that the compounds studied are oxidised via reaction with singlet oxygen. Values for the rate constants for reaction of singlet oxygen with compounds I-III have been determined over the temperature range 293–308 K, and the energy of activation and entropy of activation for the reactions have been determined. The data have been interpreted in terms of the site of attack of singlet oxygen on the compounds. 相似文献
67.
Leontine T. Colon Dirk J. Budding L. C. Paul Keizer Martin M. J. Pieters 《European journal of plant pathology / European Foundation for Plant Pathology》1995,101(4):441-456
Four components of partial resistance toPhytophthora infestans were measured after inoculation in the greenhouse and in the field ofSolanum arnezii x hondelmannii, S. berthaultii, S. circaeifolium, S. leptophyes, S. microdontum, S. sparsipilum, S. sucrense andS. vernei, and four hybrid progenies ofS. microdontum withS. tuberosum. The four components were infection efficiency, lesion growth rate, generation time and sporulation capacity. The results were compared with resistance ratings derived from field experiments, and with observations made on the potato cultivars Bintje, Bildstar, Libertas and Pimpernel. Genetic variation for all components was found, while the relative importance of the components of partial resistance appeared to vary between the species. InS. microdontum, generation time, infection efficiency and lesion growth rate, and inS. tuberosum infection efficiency, lesion growth rate and sporulation capacity appeared positively associated, but in other species no such association was found. A strong hypersensitive reaction, the expression of which appeared to depend on environmental conditions, was found inS. microdontum. ForS. berthaultii, infection efficiency appeared to be the main resistance component.Abbreviations ADPC
area under the disease progress curve
- IE
infection efficiency
- LGR
lesion growth rate
- GT
generation time
- SC
sporulation capacity 相似文献
68.
Paul B. Rodgers 《Pest management science》1993,39(2):117-129
All living organisms are subject to predation, parasitism or competition from other organisms. The study of these interactions has led to the identification of many potential opportunities for the use of living organisms as biopesticides to protect agricultural crops against insect pests, fungal, bacterial and viral diseases, weeds, nematodes and mollusc pests. A range of biopesticide products (including as active agents bacteria, fungi, nematodes, protozoa, viruses and beneficial insects) are now available commercially for control of insect pests, fungal and bacterial diseases and weeds. However, world biopesticide sales in 1990 were estimated to be $120 million, representing less than 0–5% of the world agrochemical market. Over 90% of biopesticide sales are represented by a single product type, containing Bacillus thuringiensis Berl., for control of insect pests. Nevertheless, biopesticide sales are estimated to be increasing at 10–25% per annum whilst the world agrochemical market is static or even shrinking. There has been a significant renewal of commercial interest in biopesticides as evidenced by the substantial number of alliances forged between major agrochemical companies and biotechnology companies which allow these major companies access to marketing rights to novel biopesticides. This paper reviews the current commercial status of biopesticides and discusses the technical and commercial constraints which have impeded development of biopesticides in the past. Novel developments in R&D, which may enable some of these constraints to be overcome, are examined by reference to a number of specific examples (some of which arise from the author's own experience in a biotechnology company). The future prospects for biopesticides are discussed in the light of technical advances and commercial and regulatory requirements. 相似文献
69.
许多猪场只是充分应用了现有的知识并注意了其细节 ,就提高了其小母猪的生产成绩 相似文献
70.
BA和激素对试管番茄愈伤组织形态发生的影响 总被引:12,自引:0,他引:12
用番茄‘Bonny Best’品种的子叶和下胚轴作为外植体,在MS附加不同水平的BA和激素的培养基中,愈伤组织形态发生的情况是不同的。本试验结果表明:在相同的植物生长调节剂水平下,番茄子叶外植体较下胚轴外植体更容易形成愈伤组织和生根;番茄子叶和下胚轴愈伤组织的形成要求不同的激素水平,较高的水平适合于子叶愈伤组织的生长,而下胚轴愈伤组织的生长要求较低的激素水平;较高浓度的BA诱导子叶和下胚轴外植体形成白色紧密的愈伤组织,而且茎的分化出现较早,较低水平的BA产生疏松的愈伤组织,分化效迟;在MS BA22.2-44.4μM IAA1-5μM的培养基上,番茄子叶和下胚轴切段可直接分化成茎;在无激素MS培养基上,下胚轴切段可直接成苗;疏松的愈伤组织是进行悬浮培养的良好材料,可利用它们进行原生质体培养和抗性克隆的筛选。 相似文献