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1.
Etiology of the stomatitis pneumoenteritis complex in Nigerian dwarf goats. 总被引:3,自引:1,他引:2
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F M Hamdy A H Dardiri O Nduaka S S Breese Jr E C Ihemelandu 《Canadian journal of veterinary research》1976,40(3):276-284
The causative agent of stomatitis pneumoenteritis complex was isolated in domesticated goats and Vero cell culture. It was identified immunologically and morphologically as identical with the "Peste des Petits Ruminants" virus. There were cross reactions between stomatitis pneumoenteritis complex virus isolate and rinderpest virus by immunodiffusion and complement fixation tests but no cross neutralization. Goats recovered from stomatitis pneumoenteritis complex were protected against a challenge with rinderpest virus that was lethal to control goats. Ultrastructural morphology revealed intracytoplasmic and intranuclear inclusions made up of random arrays of fibrillar strands. Pleomorphic particles budded from the plasma membrane of infected cells and enveloped virions were seen extracellularly. Specific ferritin tagging was demonstrated in the stomatitis pneumoenteritis complex virus infected cells treated with homologous and peste des petits ruminants viral antibody systems but little, if any, tagging in the heterologous rinderpest system. 相似文献
2.
E. L. Breese 《Grass and Forage Science》1997,52(4):341-342
3.
M.?Z.?FanEmail author J.?M.?Dinwoodie P.?W.?Bonfield M.?C.?Breese 《Wood Science and Technology》2004,38(1):53-68
This paper examines the dimensional instability of cement bonded particleboard (CBPB) and discusses the behaviour of CBPB during cyclic changes in relative humidities (RH). The results indicated that the changes of CBPB in both mass and dimensions reflected the changes in RH; in a cycle 90–65–35–65–90%RH the change of per percentage change in RH was 1.0:1.3:1.3:2.5 for mass, 1:2:2:1 for length and 1.3:1.1:1.0:1.0 for thickness. The changes were closely related to the structure of CBPB and the nature of the cement paste and wood chips. Thickness change was double that of the length change between 65 and 35%RH and triple that between 65 and 90%RH. The rate of change in mass was much higher than that in dimensions. The hysteresis loops were dissimilar to those of other wood and wood-based materials, with the loops of mass change closed between 65 and 90%RH, while the loops for dimensional changes were open. A set of the former loops moved upward and the latter moved downward with increasing number of cycles, corresponding to an accumulated increase in mass, but decrease in dimensions. The models developed for CBPB under constant and a single changing RH were successfully applied to changes under cyclic RH.The sorption behaviour and dimensional movement of CBPB has been shown to be influenced not only by RH, but also by its intermediate history, with the maximum values for change within every phase of sorption, in both mass and dimensions, being higher for the cycling between 35–90%RH than the cycling regime 35–65–90%RH. The ratios of dimensional changes to mass change of CBPB were greater under the latter regime than under the former regime.The senior author wishes to thank Professor W.B. Banks of University of Wales, Bangor for his constructive discussions and assistance and the British Council for partly financial support. 相似文献
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M.?Z.?FanEmail author J.?M.?Dinwoodie P.?W.?Bonfield M.?C.?Breese 《Wood Science and Technology》2004,37(5):373-383
Previous papers have quantitatively indicated that the total movement of cement bonded particleboard (CBPB) is equal to the sum of the movement of its components. This paper examined the efficacy of the law of mixtures when applied to the movement of a wood-cement composite under internal swelling or shrinkage stresses. Abundant data generated in companion papers were first manipulated to develop the universal formulae for predicting the movement of components. In conjunction with previous numerical results from image analysis of the structure of CBPB, and the orientated elasticity and stress algorithms, the models for theoretically predicting mass and dimensional changes of CBPB were derived. Validation studies were conducted and these demonstrated an excellent agreement of the theoretical predictions with experimental data for both mass and dimensional changes of CBPB due to internal swelling or shrinkage stresses during adsorption and desorption. The success also implied that CBPB can be treated as a composite and its properties can be well derived by the law of mixtures even though CBPB is an unusual type of composite having a very high volume fraction of wood chips, but a very high mass fraction of cement paste.Notation ERT
Mean transverse modulus of elasticity of wood
- EL
Longitudinal modulus of elasticity of wood
- Ep
Modulus of elasticity of cement paste
- Ewa
Modulus of elasticity of embedded wood chips at angle
- E
Modulus of elasticity of wood chips at direction
- E
Modulus of elasticity of wood chips at direction
- GLRT
Mean transverse shear modulus of wood
- L(T)cp
Length/width (thickness) change of CBPB at angle
- L(T)p
Length (thickness) change of cement paste
- mpf
Mass fraction of cement paste in unit mass of CBPB
- mwf
Mass fraction of wood chips in unit mass of CBPB
- Mcpj
Mass change of CBPB at the various conditions tested
- Mpj
Mass change of cement paste at corresponding conditions
- Mwj
Mass change of wood chips at corresponding conditions
- M(L; T)w/P
Mass, length or thickness changes of wood chips or cement paste at various conditions
- t
Duration of exposure
- LRT
Mean transverse Poissons ratio of wood
- Vpf
Volume fraction of cement paste in unit mass of CBPB
- Vwf
Volume fraction of wood chip in unit mass of CBPB
- cp
Density of CBPB
- k
Density of wood chip or cement paste
- cp
Overall stresses of CBPB at angle
- L
Stress in the longitudinal direction of wood
- RT
Mean stress in the transverse direction of wood
- p
Stress of cement paste
- w
Stress of the wood chips at angle
-
Stress of the wood chips at direction
-
Stress of the chip at direction
- cp
Strain in CBPB
- p
Strain of cement paste
- WL
Strain in the length of wood chips
- WT
Strain in the thickness of wood chips
- w
Strain in wood chips
-
Angle between the longitudinal direction of wood chips and surfaces or edges of CBPB
-
Angle between wood chips and edges (length direction) of CBPB
-
Angle between wood chip and vertical coordinate
- A, B, C
Coefficients related to the feature of materials and exposure conditions
The senior author wishes to thank Professor W.B. Banks of University of Wales, Bangor for his constructive discussions and assistance and the British Council for partly financial support. 相似文献
6.
M.?Z.?FanEmail author P.?W.?Bonfield J.?M.?Dinwoodie M.?C.?Breese 《Wood Science and Technology》2004,38(5):349-362
As part of an extensive programme of research aimed at a better understanding of the dimensional instability of cement bonded particleboard (CBPB) and establishing methods of improving its stability, this paper discusses the treatment processes for stabilisation of CBPB. CBPB as a composite of wood chips and reacted Portland cement is unstable in service. One solution to this deficiency is to treat the CBPB product to reduce its magnitude. Three treatment processes, namely, storage of, pre-drying and application of surface coatings on CBPB, were investigated. The results indicated that all three treatments were able to reduce both dimensional and mass change of CBPB, but the efficacy of the treatments was closely related to their schedules. Prolonged storage resulted in a stabilisation of CBPB due to further hydration and carbonation of CBPB. Mass change of CBPB with 12 month storage was only about 2/3–3/4 that with 2 month storage under changing relative humidity (RH). A pre-drying process resulted in a structure alternation of CBPB and stabilised it permanently. A considerably irreversible mass decrease and dimensional shrinkage occurred when re-wetting at 65%RH: about 0.7% and 3% for mass, 0.02% and 0.12% for length, and 0.08% and 0.19% for thickness, respectively for 35%RH and 105°C pre-drying CBPB. However, mass change was independent of the pre-drying schedules after exposure at 90%RH, while irreversible dimensional shrinkage remained. Surface coating had a significant influence on the behaviour of CBPB due to physical and chemical reaction. The ranking in effectiveness of sealers was: proprietary system greater than model systems, and solvent-borne sealers greater than water-borne sealers. Compared with uncoated CBPB, that which is coated with the most effective sealer showed 70–90% reduction in both mass and dimensions over the whole range of RH exposure with the exception of the range from 65–90%RH. All coatings also showed a strong resistance to carbonation of CBPB. 相似文献
7.
AA da Rocha ICN da Cunha BB Ederli AP Albernaz CR Quirino 《Reproduction in domestic animals》2009,44(S2):313-315
Polyunsaturated fatty acids are important membrane components that influence membrane integrity and fluidity. In the present study, the effect of oral supplementation for 60 days with essential fatty acids (omega 3, 6 and 9) and vitamin E on canine semen quality was evaluated. Sixteen dogs were selected for the experiment; eight were used as the control group and eight received the fatty acid supplemented diet for 60 days. Semen samples were taken every 15 days during the entire experimental period and were analyzed for volume (ml), motility (%), vigour (0–5), concentration (×106 /ml), morphology of spermatozoa (%), plasma membrane integrity (%; using the hyposmotic swelling test) and thermoresistance (motility and vigour after 4 h at 38°C). We concluded that, daily supplementation with omega 3, omega 6 and omega 9 fatty acids, together with vitamin E, for a period of 60 days, significantly increased the semen volume of the treated group after 15 days of supplementation; the vigour and concentration of spermatozoa were superior after the first month of supplementation, while the percentage of morphologically abnormal spermatozoa decreased and the cells were protected against thermal stress. 相似文献
8.
Inoculation of plants by spraying with a suspension of zoospores (released from sporangia of Sclerospora graminicola ) induced immediate encystment of the zoospores and drastically reduced their ability to cause disease. The incidence of infection in spray-inoculated pearl millet seedlings was reduced from 90% when sporangia were sprayed, to less than 30% when zoospores were sprayed. Rapid encystment was observed when zoospores were sprayed from both a hand-pumped sprayer and a compressed-gas sprayer and was probably caused by shearing forces. Chilling suspensions of sporangia prior to spraying delayed zoospore release and was an effective method for maintaining infection potential. Disease incidence was higher when sporangia were chilled to 0·2°C rather than to 4°C. Chilling resulted in some abnormal zoospore structures being released from sporangia when suspensions were returned to 20°C. The frequency of these structures increased with increasing chilling time. For seedlings sprayed with sporangia before zoospore release, a small reduction in disease incidence was observed when chilled inoculum was used, probably due to cold disruption of zoosporogenesis. For large-scale disease resistance screening, this reduction is outweighed by the benefit of a uniform and adequately high disease pressure that can be obtained over many hours using chilled spore suspensions. 相似文献
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10.
Michael H. Breese 《Pest management science》1977,8(3):264-269
The results of trials with some synthetic pyrethroids, especially cypermethrin and permethrin, against pests of cotton, various fruits, vegetables and brassicas are summarised. These compounds and cypermethrin in particular have given good results at low dosages against many insect species on these crops. Cypermethrin shows promise against ectoparasites attacking sheep and cattle and also is being evaluated for various non-agricultural outlets. 相似文献