A modified fluorometric method to quantify the concentration effect (pI₅₀) of photosystem II-inhibiting herbicides     

Masaki Hiraki  Wim J. Vredenberg  Jack J.S. van Rensen  Ko Wakabayashi 《Pesticide biochemistry and physiology》2004,80(3):183-191

Chlorophyll fluorescence induction curves of isolated thylakoids were measured in the absence and in the presence of various concentrations of photosystem II-inhibiting herbicides. A mathematical program was applied to simulate the curves. Based on these simulated curves a new method is developed to determine the concentration effect (pI₅₀) of the herbicides. The results of the new method correspond well with reported values in the literature. The method is very convenient and time-saving.  相似文献   

Clinical presentation and magnetic resonance imaging findings in 11 dogs with eosinophilic meningoencephalitis of unknown aetiology          下载免费PDF全文

T. J. A. Cardy  I. Cornelis 《The Journal of small animal practice》2018,59(7):422-431

  相似文献   

Evaluation of functional muscle anatomy scalability in the canine hind limb     

Billy P. R. Dries  Ilse Jonkers  Wim Van Den Broeck  Benedicte Vanwanseele  Lieve DeRycke  Walter Dingemanse  Jos Vander Sloten  Henri Van Bree  Ingrid Gielen 《Anatomia, histologia, embryologia》2021,50(3):637-644

In contrast to other mammals, the large variation in dog sizes is not accompanied by any significant genetic re-organization. In order to study the relationship between body mass, limb length and the functional anatomical muscle parameters of the canine hind limb, a large dataset comprising of muscle masses, optimal muscle fibre lengths and physiological cross-sectional area's (PCSA) were acquired for twenty-five muscles in ten dogs of sizes varying between 20 kg and 52 kg. The potential of body mass and limb length for reliably scaling individual muscle masses, optimal muscle fibre lengths and PCSA's were examined. For the majority of the muscles of the canine hind limb, neither body mass nor limb length were reliable scaling parameter for either muscle masses, PCSA's and optimal fibre length. These results indicate the need of a breed-specific approach to musculoskeletal modelling in future canine musculoskeletal research.  相似文献   

Nutrient requirements and low-cost balanced diets,based on seasonally available local feedstuffs,for local pigs on smallholder farms in Western Kenya     

Natalie Ann Carter  Catherine Elizabeth Dewey  Lian Francesca Thomas  Ben Lukuyu  Delia Grace  Cornelis de Lange 《Tropical animal health and production》2016,48(2):337-347

  相似文献   

Toxicodynamics of insecticidal action: An introduction     

Wim Welling 《Pest management science》1979,10(6):540-546

  相似文献   

Visualizing signals moving in cells     

Weijer CJ 《Science (New York, N.Y.)》2003,300(5616):96-100

Cells display a highly complex spatiotemporal organization, required to exert a wide variety of different functions, for example, detection, processing, and propagation of nerve impulses by neurons; contraction and relaxation by muscle cells; movement by leukocytes; and adsorption and secretion of nutrients and metabolites by epithelial cells lining the gut. Successful execution of these complex processes requires highly dynamic information transfer between different regions and compartments within cells. Through the development of fluorescent sensors for intracellular signaling molecules coupled with improved microscopic imaging techniques, it has now become possible to investigate signal propagation in cells with high spatial and temporal resolution.  相似文献   

Electromyographic activity of the hyoepiglotticus muscle and control of epiglottis position in horses     

Holcombe SJ  Cornelisse CJ  Berney C  Robinson NE 《American journal of veterinary research》2002,63(12):1617-1621

OBJECTIVE: To determine whether the hyoepiglotticus muscle has respiratory-related electromyographic activity and whether electrical stimulation of this muscle changes the position and conformation of the epiglottis, thereby altering dimensions of the aditus laryngis. ANIMAL: 6 Standardbred horses. PROCEDURE: Horses were anesthetized, and a bipolar fine-wire electrode was placed in the hyoepiglotticus muscle of each horse. Endoscopic images of the nasopharynx and larynx were recorded during electrical stimulation of the hyoepiglotticus muscle in standing, unsedated horses. Dorsoventral length and area of the aditus laryngis were measured on images obtained before and during electrical stimulation. Electromyographic activity of the hyoepiglotticus muscle and nasopharyngeal pressures were measured while horses exercised on a treadmill at 50, 75, 90, and 100% of the speed that produced maximum heart rate. RESULTS: Electrical stimulation of the hyoepiglotticus muscle changed the shape of the epiglottis, displaced it ventrally, and significantly increased the dorsoventral length and area of the aditus laryngis. The hyoepiglotticus muscle had inspiratory activity that increased significantly with treadmill speed as a result of an increase in phasic and tonic activity. Expiratory activity of the hyoepiglotticus muscle did not change with treadmill speed in 4 of 6 horses. CONCLUSIONS AND CLINICAL RELEVANCE: Findings reported here suggest that contraction of the hyoepiglotticus muscle increases dimensions of the airway in horses by depressing the epiglottis ventrally during intense breathing efforts. The hyoepiglotticus muscle may be an important muscle for dilating the airway in horses, and contraction of the hyoepiglotticus muscle may induce conformational changes in the epiglottis.  相似文献   

F4 receptor-independent priming of the systemic immune system of pigs by low oral doses of F4 fimbriae     

Van den Broeck W  Bouchaut H  Cox E  Goddeeris BM 《Veterinary immunology and immunopathology》2002,85(3-4):171-178

Oral administration of F4 fimbriae of Escherichia coli induces intestinal mucosal immune responses in F4 receptor-positive (F4R(+)) pigs, but not in F4R(-) pigs. We examined whether F4 fimbriae in F4R(-) animals behave like a food antigen and can induce oral tolerance. Therefore, F4R(+) and F4R(-) pigs were fed 2mg of F4 and challenged i.m. to evaluate the effect of oral F4 on the systemic immune system. As control antigen, two different oral doses (2 and 600 mg) of OVA were used. Thirty days after the i.m. OVA challenge, the OVA-specific serum IgG titre in 600 mg-fed pigs was lower than that in non-fed animals, indicating that tolerance was induced. Conversely, in the 2mg-fed pigs a rapid increase of OVA-specific IgG with higher titres than those in non-fed pigs was seen following challenge, indicating a priming of the systemic immune system. A similar priming was seen in both F4-fed F4R(-) and F4R(+) pigs. Upon challenge, non-fed pigs displayed a primary immune response with a slow increase of F4-specific serum IgG, whereas F4-fed F4R(-) and F4R(+) pigs showed secondary responses with a rapid increase of serum IgG. This was expected in F4R(+) pigs, as in these animals oral F4 induces F4-specific antibody-secreting cells in the spleen, suggesting a priming of the systemic immune system. However, also the F4-fed F4R(-) pigs displayed a secondary response, despite the failure to detect a response upon oral F4 administration. These findings suggest that the F4 antigen, at a dose of 2 mg, behaves like a common food antigen in F4R(-) pigs, namely it induces a systemic priming.  相似文献   

Relation between Soil Health, Wave-like Fluctuations in Microbial Populations, and Soil-borne Plant Disease Management     

Ariena H. C. van Bruggen  Alexander M. Semenov  Anne D. van Diepeningen  Oscar J. de Vos  Wim J. Blok 《European journal of plant pathology / European Foundation for Plant Pathology》2006,115(1):105-122

A healthy soil is often defined as a stable soil system with high levels of biological diversity and activity, internal nutrient cycling, and resilience to disturbance. This implies that microbial fluctuations after a disturbance would dampen more quickly in a healthy than in a chronically damaged and biologically impoverished soil. Soil could be disturbed by various processes, for example addition of a nutrient source, tillage, or drying-rewetting. As a result of any disturbance, the numbers of heterotrophic bacteria and of individual species start to oscillate, both in time and space. The oscillations appear as moving waves along the path of a moving nutrient source such as a root tip. The phase and period for different trophic groups and species of bacteria may be shifted indicating that succession occurs. DGGE, Biolog and FAME analysis of subsequent populations in oscillation have confirmed that there is a cyclic succession in microbial communities. Microbial diversity oscillates in opposite direction from oscillations in microbial populations. In a healthy soil, the amplitudes of these oscillations will be small, but the background levels of microbial diversity and activity are high, so that soil-borne diseases will face more competitors and antagonists. However, soil-borne pathogens and antagonists alike will fluctuate in time and space as a result of growing plant roots and other disturbances, and the periods and phases of the oscillations may vary. As a consequence, biological control by members of a single trophic group or species may never be complete, as pathogens will encounter varying populations of the biocontrol agent on the root surface. A mixture of different trophic groups may provide more complete biological control because peaks of different trophic groups occur at subsequent locations along a root. Alternatively, regular addition of soil organic matter may increase background levels of microbial activity, increase nutrient cycling, lower the concentrations of easily available nutrient sources, increase microbial diversity, and enhance natural disease suppression.  相似文献   

Performance of forest groups in achieving multifunctional forestry in Flanders     

Peter Van Gossum  Wim De Maeyer 《Small-Scale Forestry》2006,5(1):19-36

The forest group is a new policy instrument in Flanders (northern Belgium) to realise multifunctional forest management. This group was introduced in 1995 and organises the various kinds of forest owners, private as well as public, on a local basis (mean working area 751 km²), with voluntary participation (as in all forest owner organisations). This study evaluates forest groups in Flanders through an analysis of their relevance, effectiveness, utility and implementation. The targets of forest groups are relevant to the evolving needs and priorities at the local, regional, national and international level. The effectiveness analysis reveals that most indicators — including the quantity of timber harvest, the number of members, the forest area with an accepted management plan, the area under management and the area with small-scale ecological measures — have been improving between 1995 and 2004. The utility analysis emphasises that the owners are motivated because the forest group provides information and increases knowledge, includes the owner into a collective management plan, offers a platform for sharing management experiences and acts as a union force against the government. However, the forest group is not the solution to introduce multifunctional forest management by all forest owners. The implementation analysis identifies a number of impeding factors, including the imbalance between rights and duties, inconsistencies between various policy aims, and failure of forest groups to act as a common forum for all stakeholders in their working area.  相似文献