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排序方式: 共有151条查询结果,搜索用时 31 毫秒
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2.
Leif Sundheim Alan R. Poplawsky Albert H. Ellingboe 《Physiological and Molecular Plant Pathology》1988,33(3)
Two chitinase encoding EcoRI fragments from the enteric soil bacterium Serratia marcescens were cloned. From a genomic library of 5686 transductants, 21 expressed chitinase activity as indicated by clearing of a chitin-containing medium. The chitinase encoding clones could be divided into two groups. Four had an 18kb EcoRI fragment and 17 had a 9·4 kb EcoRI fragment. In Southern hybridization experiments the 18kb fragment showed no homology to the 9·4 kb fragment and restriction enzyme maps indicated no similarity. Triparental mating with fluorescent Pseudomonas spp. yielded transconjugants that expressed chitinase activity, inhibited growth of Fusarium oxysporum f. sp. redolens germ tubes and reduced disease of radish caused by the same fungus. 相似文献
3.
Nils-Erik Ahlberg Med Dr Fredrik Hoppe VDM Ulrike Kelter MD† Leif Svensson PHD‡ 《Veterinary radiology & ultrasound》1985,26(2):43-47
The influence of body position on volume and x-ray attenuation of the lungs of three Beagles was investigated with computed tomography. In left and right lateral recumbency, the dependent lung had decreased volume and increased x-ray attenuation compared with ventral recumbency. Volume and x-ray attenuation of the nondependent lung, however, were unchanged. In dorsal recumbency, there was a vertical gradient of x-ray attenuation being increased dorsally and decreased ventrally compared with ventral recumbency where regional differences in x-ray attenuation were not found. Results indicate a risk of overlooking a mass in the dependent pulmonary parenchyma of dogs in lateral and dorsal recumbency. Regional differences in x-ray attenuation of the lungs of dogs can be avoided if the radiographs are obtained with the dog in ventral recumbency. 相似文献
4.
Induction of discolored wood in Scots pine (Pinus sylvestris L.) trees by treatment with ethylene, carbon dioxide, nitrogen (hypoxia) or wounding from early April to late September was investigated. All treatments induced formation of discolored wood upward and downward from the drill hole. The amount of discolored wood formed above the drill hole depended on the treatment in the following order: ethylene > carbon dioxide = nitrogen > wounding; and below the drill hole in the order: ethylene > carbon dioxide = nitrogen = wounding. Based on chemical analyses (HPLC/UV, GS/MS, LC/MS and 1H-NMR), discolored wood induced by wounding or treatment with ethylene or carbon dioxide showed compositional similarities to natural heartwood, whereas discolored wood induced by nitrogen treatment showed fewer similarities to natural heartwood. The results suggest that ethylene is an important factor controlling heartwood formation, although wounding and internal concentrations of carbon dioxide may also play a role. 相似文献
5.
Influence of Disease Process and Duration on Acute Phase Proteins in Serum and Peritoneal Fluid of Horses with Colic 下载免费PDF全文
T.H. Pihl E. Scheepers M. Sanz A. Goddard P. Page N. Toft P.H. Andersen S. Jacobsen 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(2):651-658
Background
The acute phase proteins (APP) serum amyloid A (SAA), haptoglobin, and fibrinogen are valuable blood biomarkers in equine inflammatory diseases, but knowledge of factors influencing their concentrations in blood and peritoneal fluid (PF) of horses with colic is needed.Objectives
The objective of this study was to investigate the influence of demographics (age, sex, breed), disease process (simple obstruction, strangulating obstruction, inflammatory), disease location, disease duration, hypovolemia, and admission hospital on concentrations of APP, lactate and white blood cell counts (WBC) in horses with colic admitted to 2 referral hospitals.Animals
The study included 367 horses with colic admitted at 2 referral hospitals.Methods
Prospective multicenter observational study of clinical data, as well as blood and PF biomarkers. Associations between biomarker concentrations and clinical variables were analyzed using multivariate linear regression analysis.Results
Increasing pre‐admission duration of colic was associated with increased concentrations of APP in blood and PF. Blood concentrations of SAA and fibrinogen were associated with disease process (inflammatory, strangulations, simple obstructions) in more colic duration groups (5–12 and >24 hours) than any of the other biomarkers. No relevant associations between demographic factors, hospital, or hydration status and the measured biomarkers were found.Conclusions and Clinical Importance
In horses with colic, concentrations of APP are associated mainly with disease process and duration of colic and may thus be used for assessment of disease independently of demographic or geographic factors. Serum amyloid A may be a diagnostic marker for use in colic differential diagnosis, but further evaluation is needed. 相似文献6.
Tocopherols (alpha, beta, gamma, and delta) and Trolox were found to deactivate triplet-excited riboflavin in homogeneous aqueous solution (7:3 v/v tert-butanol/water) with second-order reaction rates close to diffusion control [k2 between 4.8 x 10(8) (delta-tocopherol) and 6.2 x 10(8) L mol(-1) s(-1) (Trolox) at 24.0 +/- 0.2 degrees C] as determined by laser flash photolysis transient absorption spectroscopy. In aqueous buffer (pH 6.4) the rate constant for Trolox was 2.6 x 10(9) L mol(-1) s1 and comparable to the rate constant found for ascorbate (2.0 x 10(9) L mol(-1) s(-1)). The deactivation rate constant was found to be inferior in heterogeneous systems as shown for alpha-tocopherol and Trolox in aqueous Tween-20 emulsion (approximately by a factor of 4 compared to 7:3 v/v tert-butanol/water). Neither beta-carotene (7:3 v/v tert-butanol/water and Tween-20 emulsion), lycopene (7:3 v/v tert-butanol/water), nor crocin (aqueous buffer at pH 6.4, 7:3 v/v tert-butanol/water, and Tween-20 emulsion) showed any quenching on the triplet excited state of riboflavin. Therefore, all carotenoids seem to reduce the formation of triplet-excited riboflavin through an inner-filter effect. Activation parameters were based on the temperature dependence of the triplet-excited deactivation between 15 and 35 degrees C, and the isokinetic behavior, which was found to include purine derivatives previously studied, confirms a common deactivation mechanism with a bimolecular diffusion-controlled encounter with electron (or hydrogen atom) transfer as rate-determining step. DeltaH for deactivation by ascorbic acid, Trolox, and homologue tocopherols (ranging from 18 kJ mol(-1) for Trolox in Tween-20 emulsion to 184 kJ mol(-1) for ascorbic acid in aqueous buffer at pH 6.4) showed a linear dependence on DeltaS (ranging from -19 J mol(-1) K(-1) for Trolox in aqueous buffer at pH 6.4 to +550 J mol(-1) K(-1) for ascorbic acid in aqueous buffer pH 6.4). Among photooxidation products from the chemical quenching, lumicrome, alpha-tocopherol quinones and epoxyquinones, and alpha-tocopherol dimers were identified by ESI-QqTOF-MS. 相似文献
7.
Hedegaard RV Frandsen H Granby K Apostolopoulou A Skibsted LH 《Journal of agricultural and food chemistry》2007,55(2):486-492
Acrylamide formation from asparagine and glucose in different ratios in neutral glycerol/water mixtures was found to increase with decreasing water activity (0.33 < or = aw < or = 0.71 investigated) and increasing temperature (120 degrees C < or = T < or = 160 degrees C investigated). The initial rate of acrylamide formation was found to be approximately proportional to the asparagine concentration for an excess of asparagine, but less dependent on an excess of glucose. A steady-state concentration of acrylamide was established at 160 degrees C after 1 h for aw = 0.33 (30 microg x L-1 for GLU:ASN = 10:1, 11 microg x L-1 for GLU:ASN = 1:1, and 130 microg x L-1 for GLU:ASN = 1:10) and for aw = 0.47 (15 microg x L-1 for GLU:ASN = 10:1 and 80 microg x L-1 for GLU:ASN = 1:10), suggesting a protection by glucose against acrylamide degradation. The energy of activation, as estimated from the temperature dependence of the initial rate, increased with decreasing aw despite a higher rate of formation of acrylamide at low aw. For high aw, water elimination from a reaction intermediate is suggested to be rate determining. For low aw, the increase in energy of activation (and enthalpy of activation) is accordingly counteracted by a more positive entropy of activation, in agreement with decarboxylation as rate determining at low aw. 相似文献
8.
Mogens T Christophersen Nana Dupont Kristina S Berg-S?rensen Christel Konnerup Tina H Pihl Pia H Andersen 《Acta veterinaria Scandinavica》2014,56(1):20
Background
Outcomes of colic treatment are of great interest to clinicians, horse owners and insurers. One commonly used criterion of success is the overall short-term survival rate. This is used as to compare treatments and to measure quality of veterinary care, but may be biased by demographic or social factors such as attitudes towards animal suffering and euthanasia. The aims of this study were to 1) describe and analyse characteristics in horses with signs of colic referred to the University Hospital for Large Animals (UHLA), University of Copenhagen, Denmark over a 10-year period and 2) to compare these rates with those published in other comparable studies.Results
The overall survival rate for colic horses over the 10-year study period was 68% (confidence intervals (CI): 66–71%; 1087/1588). In the medical group, 1093 horses, short-term survival was 87% (CI: 85–89%). Thirty one % of referred horses were given diagnoses requiring surgical intervention (CI: 29–33%). In this group 32% of the horses were euthanized before surgery (CI: 28–36%; 159/495). Of the surgical cases 27% (CI: 23-31%) were euthanized or died during surgery. Of the horses that recovered from surgery 25% died or were euthanized (CI: 19–32%; 48/189), while 75% survived to discharge (CI: 68–81%).Conclusions
The short term survival rates of Danish horses with colic were similar or lower to those reported from other countries. Apart from variability of veterinary care, attitudes towards euthanasia vary among the countries, which may bias the outcomes. This study indicates that qualitative interview studies on owners’ attitudes towards animal suffering and euthanasia need to be conducted. Our opinion is that survival rates are not valid as sole indicators of quality of care in colic treatment due to selection bias. If the survival rates are to be compared between hospitals, techniques or surgeons, prospective studies including mutually agreed-on disease severity scores and a predefined set of reasons for euthanasia are needed. 相似文献9.
Leif Hallbcken 《植物养料与土壤学杂志》1992,155(1):51-60
During the past 60 years there has been a considerable decline in pH in mineral soil beneath spruce and beech stands at Tönnersjöheden Experimental Forest in south-west Sweden. In this report an attempt is made to estimate the corresponding declines in base cation pools. The exchangeable storage of Na, K, Ca and Mg in soil, down to 70 cm depth, is calculated to have decreased by 57–60 per cent for beech and by 56–74 per cent for the spruce stands during the period 1927–1984. The calculated cation depletions are compared with estimated nutrient uptake in biomass, base cation release by weathering and leaching losses due to percolation of strong mineral acids and organic anions during the period. The biological acidification may explain about 50–60 per cent of the total losses of base cations from soil, the cation accumulation in biomass then explain 41–43 per cent units for beech and 34–45 per cent units for spruce. The estimated losses of base cations due to acid rain correspond to an amount of cations similar to that accumulated in the spruce biomass during one generation. 相似文献
10.
Møller JK Parolari G Gabba L Christensen J Skibsted LH 《Journal of agricultural and food chemistry》2003,51(5):1224-1230
Parma hams at various processing stages were investigated by surface autofluorescence spectroscopy. Fluorescence "landscapes" of raw meat and salted (3 months), matured (11 and 12 months), and aged (15 and 18 months) Parma hams were obtained, and a three-dimensional data array (sample x emission x excitation) was used to develop a PARAFAC model including five components, which all exhibited characteristics of pure fluorophores regarding both excitation and emission spectra. The relative amount of each component related strongly to the processing stage, and sample age showed good correlation to fluorescence data (R = 0.98), with a relative error of prediction of approximately 1 month. Fluorescence measurements from samples of either semimembranosus or biceps femoris were used to predict chemical or sensory reference data, yielding good correlation for biceps femoris data, thereby enabling moisture content, sensory and instrumental color, and proteolysis value to be fairly well predicted. Overall, surface autofluorescence of Parma hams proved to hold relevant information, relating to major chemical/physical changes during processing. It is concluded that fluorescence spectroscopy has potential as an innovative method of quality control in dry-cured ham. 相似文献