Biochemical activities in peat sterilized by gamma-irradiation     

Keith A. Brown 《Soil biology & biochemistry》1981,13(6):469-474

Peat is effectively sterilized by 4 Mrad of γ-irradiation and microbial sulphate-reducing activity is abolished by this dose. Enzymatic activities persist to a variable extent, but have higher inactivation coefficients than are usually encountered with soil enzymes. Inactivation coefficients (Mrad^?1) in surface peat, and in peat from 25–30 cm depth were as follows: β-d-glucosidase 0.144, 0.176: β-d-galactosidase 0.409, 0.458; $\text{β-N-}\text{acetyl-}\text{d}\text{-glucosaminidase}$ 0.201, 0.284; exo-l,4-β-d-xylosidase 0.268, 0.178: arylsulphatase 0.168, 0.174; 4-nitrophenylphosphatase 0.102, 0.118; “dehydrogenase” 0.094. 0.050; thiosulphate: cyanide sulphur transferase 0.079, 0.021. The greater radiosensitivity of the peat enzymes may be because of the absence of protection afforded by adsorption onto clay minerals, the nature of humic-colloid enzyme complex, or as a result of greater indirect damage caused by the products of radiolysis of water.  相似文献   

Nitrogen fixation by free-living heterotrophic bacteria in an oak forest: The effect of liming     

Keith Jones  David Bangs 《Soil biology & biochemistry》1985,17(5):705-709

Nitrogen-fixing heterotrophic bacteria, mainly Clostridium butyricum and, less frequently, Enterobacter agglomerons and Klebsiella pneumoniae, are found throughout the aerial and soil layers of an oak forest. However they are only active in nitrogen fixation in the soil. Soil slurry experiments show that the main factors limiting N₂ fixation in the forest are low temperature, low pH and shortage of C sources. Raising the pH of the soil with lime to pH 6, which is the optimum for N₂ fixation by C. butyricum in soil slurries, more than doubles the rate of N₂ fixation (as measured by in situ¹⁵N₂ methods) from 7.84 to 16.1 kg N ha^?1yr^?1. The N fixed by C. butyricum can rapidly be taken up by oak seedlings and translocated to the actively-growing leaves.  相似文献   

Reply     

Paul W. Shaffer  Richard P. Hooper  Keith N. Eshleman  M. Robbins Church 《Water, air, and soil pollution》1989,47(1-2):179-182

  相似文献   

Comparison of natural and roasted Turkish tombul hazelnut (Corylus avellana L.) volatiles and flavor by DHA/GC/MS and descriptive sensory analysis   总被引：1，自引：0，他引：1  

Alasalvar C  Shahidi F  Cadwallader KR 《Journal of agricultural and food chemistry》2003,51(17):5067-5072

  相似文献   

MAGNETIC RESONANCE IMAGING OF THE BRAIN OF NORMAL NEONATAL FOALS     

M. Keith  Chaffin  DVM  MS  Michael A.  Walker  DVM  Newell H.  Mcarthur  DVM  MS  PhD  Elias E.  Perris  DVM  Nora S.  Matthews  DVM 《Veterinary radiology & ultrasound》1997,38(2):102-111

Magnetic resonance imaging (MRI) was performed on gthe brain of 5 normal, anesthetized, neonatal (age 3-to-6 days) Quarter Horse foals. The objectives of the study were to develop a technique for imaging the brain of neonatal foals, and to ascertain their normal brain anatomy. Interavenous propofol was administered for induction and maintenance of general anesthesia. Using spin echo MR techniques, T1 weighted sagittal and transverse views, and spin density and T2 weighted transverse views were successfully made of each foal. MR images provided excellent visualization of many anatomic struictures of the brain and head. MRI of the bgrain is feasible for selected neonantal equine patients.  相似文献   

Effect of acetylsalicylic acid on vascular damage and myointimal proliferation in canine pulmonary arteries subjected to chronic injury by Dirofilaria immitis     

R G Schaub  J C Keith  C A Rawlings 《American journal of veterinary research》1983,44(3):449-454

The effect of aspirin (ASA) on pulmonary artery response to chronic injury induced by Dirofilaria immitis was assessed in the dog. Eight dogs were studied for 30 days after adult heartworms were transplanted into the pulmonary arteries. Four dogs were treated with ASA (325 mg/day given orally) starting 3 days before the transplantation was done. Evan's blue dye was used to locate areas of vascular damage. Vascular morphology was assessed by scanning electron microscopy and light microscopy. According to results of the morphologic studies, nontreated dogs had extensive endothelial damage and significant adhesion of leukocytes and blood platelets. Blood vessels of ASA-treated dogs had less endothelial damage. Platelet adhesion on areas of vascular damage was less than that observed in nontreated dogs. Myointimal proliferative lesions were observed in both nontreated and ASA-treated dogs. However, the lesions in nontreated dogs were larger (means 68 +/- 7 mm2) and more complex than those in ASA-treated dogs (means 20 +/- 1 mm2). The results indicated that aspirin may protect against development of myointimal proliferation resulting from chronic vascular injury. The mechanism of the ASA protection may result from a combination of antiplatelet and anti-inflammatory effects, as well as a direct protective effect on vascular endothelium.  相似文献   

The fungitoxicity of substituted 2-phenylbenzofurans     

Keith Chamberlain  Geoffrey A. Carter 《Pest management science》1980,11(5):526-532

Thirty-seven 2-phenylbenzofurans, variously substituted in the homocyclic rings, were synthesised and assessed for antifungal activity in laboratory tests. High activity was shown only by compounds containing a hydroxy group, though amino compounds were also fungitoxic but at a lower level. Possible mechanisms by which these substitutions impart fungitoxicity are discussed with particular reference to the partitioning properties of the molecule.  相似文献   

An aspirin-prednisolone combination to modify postadulticide lung disease in heartworm-infected dogs     

C A Rawlings  J C Keith  J M Losonsky  J M McCall 《American journal of veterinary research》1984,45(11):2371-2375

A combination of aspirin and prednisolone was used in an attempt to modify the pulmonary disease produced by thiacetarsamide treatment of heartworm-infected dogs. Results of 6 heartworm-infected dogs treated with prednisolone (1 mg/kg, daily for 4 weeks) and aspirin (10 mg/kg, daily for 4 weeks) after thiacetarsamide treatment were compared with previously published results of 3 groups of dogs (6 dogs/group). One of these 3 groups was a nontreated control group, another was treated with prednisolone, and the 3rd was treated with aspirin. All dogs, each with 9 adult heartworms transplanted, were treated with a 2-day, twice-a-day treatment of thiacetarsamide (1 mg/kg) 4 weeks after the transplant. Thoracic radiographs were taken before and at 1, 2, and 3 weeks after thiacetarsamide treatment to evaluate lung disease. Pulmonary arteriography was performed before and 3.5 weeks after thiacetarsamide treatment to evaluate pulmonary blood flow. After treatment, radiographs of the aspirin-prednisolone group were similar to radiographs of the prednisolone group, both with a marked attenuation of the parenchymal disease, as compared with the non-treated group. Addition of aspirin to prednisolone prevented the blood flow obstruction and intraluminal filling defects that were present in the groups not receiving aspirin. Sixteen of 54 transplanted heartworms survived thiacetarsamide treatment in both prednisolone-treated groups, in contrast to complete elimination of heartworms in the nontreated group. Aspirin may be considered for treatment of any heartworm-infected dog that does not have hemotypsis, but postthiacetarsamide use of prednisolone should be restricted to the dog that develops severe lung disease after the heartworms have been killed.  相似文献   

Rare birds identified     

Keith GS 《Science (New York, N.Y.)》1967,155(3760):269

  相似文献   

QUALITATIVE AND QUANTITATIVE THYROID IMAGING IN FELINE HYPERTHYROIDISM USING TECHNETIUM-99M AS PERTECHNETATE   总被引：1，自引：0，他引：1  

Carmel T.  Mooney  MVB  MPhil  Keith L.  Thoday  BVetMed  Phd  DVD  Jeremy J.  Nicoll  BSc  Phd  David L.  Doxey  BVM&S  PhdD 《Veterinary radiology & ultrasound》1992,33(5):313-320

Thyroid imaging using technetium-99m as pertechnetate (^99mTcO₄) was carried out in five healthy, euthyroid and 37 hyperthyroid cats using both pinhole and parallel-hole collimators. Images of greater resolution, necessary to distinguish bilateral lobe involvement, were obtained using the pinhole collimator. Per cent thyriod ^99mTcO₄ - uptake was calculated in each cat and was significanly (P < 0.001) higher in hyperthyroid compared with euthyroid cats. In the hyperthyroid cats, per cent thyroid uptake was significantly correlated with serum total thyroxine (T4) and triiodothyronine (T3) Concentrations. Per cent thyroid ^99mTcO₄ - uptake is increased in feline hyperthyrodism and may be calculated using a pinhole collimator alone at the time of qalitative assessment of the extent of thyroid tissue involvement.  相似文献