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排序方式: 共有490条查询结果,搜索用时 15 毫秒
71.
Maria Caridad Montalvo Villalba Chantal J. Snoeck Licel de los Angeles Rodriguez Lay Aurélie Sausy Dayesi Hernández López Marite Bello Corredor Barbara Marrero Sanchéz Judith M. Hübschen 《Zoonoses and public health》2023,70(1):58-68
Surveillance of hepatitis E virus (HEV) in risk groups is an important strategy to monitor its circulation pattern and to timely detect changes thereof. The aims of this cross-sectional study were to estimate the prevalence of HEV infections in pigs and humans from different regions of the country, to identify risk factors for increasing anti-HEV IgG prevalence and to characterize HEV strains. The presence of anti-HEV antibodies was assessed by commercial ELISA in serum samples from the general population, farm and slaughterhouse employees, as well as pigs sampled in the three regions of Cuba from February to September 2016. Overall, individuals with occupational exposure to swine or swine products (70/248, 28.2%) were 4 times more likely to be seropositive compared to the general population (25/285, 8.7%; OR: 4.18; p < .001). Within the risk group, risk factors included age, number of years working in a professional activity with direct exposure to swine, geographic region and distance between residence and closest professional swine setting, while wearing gloves had a protective effect. Prevalence of total anti-HEV antibodies in swine was 88.2% (165/187) and HEV RNA was detected by real-time RT-PCR in 9.2% (16/173) swine stools. All HEV strains sequenced clustered within genotype 3. Some strains clearly belonged to subtype 3a, while another group of strains was related with subtypes 3b and 3 k but partial HEV sequences did not allow unequivocal subtype assignment. These findings suggest that the high HEV exposure in Cuban individuals with swine-related occupations could be due to enzootic HEV in certain regions, direct contact with infectious animals or their products as well as environmental contamination. 相似文献
72.
The effect of a granular formulation of sodium azide, applied annually to pine nursery beds at rates of 0, 67.2, and 134.5 kg a. i. ha?1 under water seal or plastic seal, on soil fungal populations was determined over a 3-year period. Populations of fungi in the soil decreased following application of the sodium azide each year; the greatest decrease occurred at the highest rate of application. Populations of fungi in soil treated with the azide generally remained lower than in the controls throughout each of the 3 years; however, the population disparity between treated and control plots decreased in magnitude with each succeeding year. Populations of Trichoderma spp., in plots treated with 134.5 kg sodium azide ha?1, increased 2 weeks after treatment each year, and the population peaks increased in magnitude each year. In addition the effect of sodium azide (technical grade > 99%) at concentrations of 0, 2, 5, 10, 20 and 50 μg ml?1 in potato dextrose agar and blackstrap molasses agar media was determined in vitro for 14 isolates of Trichoderma harzianum. Growth and sporulation differed among the isolates and between the two media tested. Generally, the azide temporarily inhibited growth of the fungi, but the majority of the isolates were able to grow on either medium containing 50 μg sodium azide ml?1, although sporulation was more profuse on the molasses than on the potato dextrose agar medium. 相似文献
73.
Ana Casas Jose PalomarMaria Virginia Alonso Mercedes OlietSalama Omar Francisco Rodriguez 《Industrial Crops and Products》2012,37(1):155-163
In this work, the solubilities of lignin and cellulose in ionic liquids (ILs) have been analyzed and compared by COSMO-RS simulation. The excess enthalpy of the IL + lignin/cellulose mixtures is evaluated as reference property to describe the affinity of lignin and cellulose for different ionic liquids, in terms of the intermolecular interactions contributing to their mixing properties. Thus, the anion plays the main role in the dissolution process of both lignin and cellulose, in which the hydrogen bonding forces are the major interactions. The most promising anions for the cellulose and lignin dissolution are acetate, formate and chloride, whereas different cations can be employed. Computational results indicated that a rational combination of the anions and cations allows designing ILs able to dissolve with different selectivity lignin and cellulose. Some of these solutions are tested in the laboratory to validate the model employed and the regenerated solids are analyzed by FTIR spectroscopy. 相似文献
74.
75.
Empirical relationships between land use/cover and estuarine condition in the Northeastern United States 总被引:1,自引:0,他引:1
Wilfrid Rodriguez Peter V. August Yeqiao Wang John F. Paul Arthur Gold Norman Rubinstein 《Landscape Ecology》2007,22(3):403-417
Land–water interactions were examined in three regions in the Virginian Biogeographic Province; the southern shore of Cape
Cod, Massachusetts; the Hudson/Raritan region of New York; and the eastern shore of the Delmarva (Delaware/Maryland/Virginia)
Peninsula. Cumulative distribution functions were used to evaluate similarity in environmental condition among estuaries.
Spatial-setting variables (location in a river, coastal lagoon, or in open waters) were associated with variation for some
measures of estuarine condition. Patterns of coastal urban and agriculture gradients were measured and their relationship
with indicators of estuarine condition was modeled statistically. When estuaries were pooled, the highest variation explained
by spatial-setting variables was found for dissolved oxygen (DO, R
2 = 0.44) and salinity (R
2 = 0.58), with DO decreasing in river locations and salinity decreasing with rainfall and sampling locations near rivers.
The explanatory power for the other indicator variables was low and varied from 6% to 27%. Rainfall explained some of the
variation (R
2 = 0.23) in total suspended solids. Moderate (0.4 < | r | < 0.7) to strong (| r | ≥ 0.7) linear associations were found between total urban area and measures of estuarine condition. Within regions, total
urban area was positively associated with Silver (r = 0.59), Cadmium (r = 0.65), and Mercury (r = 0.47) in Cape Cod, and inversely related to DO (r = −0.65) in the Hudson/Raritan region. No associations were found in the Delmarva Peninsula study area. Total area of agriculture
showed a moderate association with Arsenic in Cape Cod, but no other associations were found in the other two regions. Our
analyses show a measurable impact of urban land use on coastal ecosystem condition over large areas of the northeastern United
States. This pattern was most evident when many different landscapes were considered simultaneously. The relationship between
urban development and estuarine condition were weaker within the individual regions studied. The use of land use/cover models
for predicting estuarine condition is a challenging task that warrants enhancements in the type, quantity, and quality of
data to improve our ability to discern relationships between anthropogenic activities on land and the condition of coastal
environments. 相似文献
76.
Recombination of O(2)(+) represents a source of fast oxygen atoms in Venus' exosphere, and subsequent collisions of oxygen atoms with hydrogen atoms lead to escape of about 10(7) hydrogen atoms per square centimeter per second. Escape of deuterium atoms is negligible, and the ratio of deuterium to hydrogen should increase with time. It is suggested that the mass-2 ion observed by Pioneer Venus is D(+), which implies a ratio of deuterium to hydrogen in the contemporary atmosphere of about 10(-2), an initial ratio of 5 x 10(-5) and an original H(2)O abundance not less than 800 grams per square centimeter. 相似文献
77.
78.
Reoviruslike agent in stools: association with infantile diarrhea and development of serologic tests 总被引:39,自引:0,他引:39
A Z Kapikian H W Kim R G Wyatt W J Rodriguez S Ross W L Cline R H Parrott R M Chanock 《Science (New York, N.Y.)》1974,185(156):1049-1053
Reoviruslike particles were visualized by electron microscopy in stool filtrates prepared from stools of infants and young children with severe acute gastroenteritis. Patients who had such particles in their stools and whose paired acute and convalescent serums were tested developed an antibody response to the reoviruslike agent, which was measured by immune electron microscopy and by complement fixation. The reoviruslike agent was antigenically related to the epizootic diarrhea of infant mice virus and the Nebraska calf diarrhea virus. 相似文献
79.
Jesus Mellado Edgar Sepulveda Jose E Garcia Alvaro Rodriguez Maria A De Santiago Francisco G Veliz Miguel Mellado 《中国农业科学(英文版)》2014,(6):1349-1354
Nineteen multiparous barren Holstein cows were subjected to an induction of lactation protocol for 21 d administering estradiol cypionate (2 mg kg-1 of body weight (BW) d-1, on day 1 to 14), progesterone (0.10 mg kg-1 of BW, on day 1 to 7), lfumethasone (0.03 mg kg-1 of BW, on day 18 to 20) and recombinant bovine somatotropin (rbST;500 mg per cow, on day 1, 6, 16 and 21). At the end of lactation and with a minimum of a 2-mon dry period, the same cows were again hormonally induced into lactation. Cows in both lactations were not artiifcially inseminated, they were milked 3 times daily and received rbST throughout lactation. Mean accumulated milk yield at 305 d in milk (DIM) did not differ between the ifrst and second induced lactations ((9 710 &#177;1 728) vs. (9 309&#177;2 150) kg;mean&#177;SD). Total milk yield ((12 707&#177;3 406) vs. (12 306&#177;4 218) kg;mean&#177;SD) and lactation length ((405&#177;100) vs. (410&#177;91) d;mean&#177;SD) were not different between the ifrst and second induced lactations. In a second study, 15 empirical models including exponential, power law, yield-density, sigmoidal and miscellaneous models were compared for their suitability by modeling 12-mon (n=334), 18-mon (n=164) and 29-mon (n=22) lactation cycles of Holsteins cows induced into lactation and treated with rbST throughout the lactation. Hoerl (Y=ab1/xxc), Wood (Y=axb exp(cx)) and Dhanoa (Y=ax(bc)exp(cx)) models were equally suitable to describe 12-mon lactations. An exponential model with ifve parameters (Y=exp(a+bx+cd2+e/x)) showed the best ift for milk yield for 18-mon lactations. The rational model (Y=a+bx/1+cx+dx2) was found to produce the closest ift for 29-mon lactations. It was concluded that, with the protocol used in the present study, multiparous cows respond favorably to a second cycle of induced lactation, with milk yield similar to that experienced during the ifrst cycle. Thus, dairy producers might be able to lengthen the productive life of infertile high producing cows with a renewal of artiifcial lactation, which would imply an overall reduction in voluntary culling of cows. Also, various equations used to describe the lactation curves demonstrated the potential for iftting monthly milk records of Holstein cows with prolonged lactations and induced hormonally into lactation. 相似文献
80.
Isolates of bovine herpesvirus-1 (BHV-1) recovered from tissue explants of trigeminal ganglia of clinically healthy cattle were studied in vitro and in an animal model, and their characteristics were compared with those of vaccine and field strains of BHV-1. The isolates could be distinguished by their plaque size on cell monolayers, but were not significantly different in their thermal inactivation profiles at 48 C. Temperature-sensitive mutants were not found among the isolates when they were grown at 41 C. Selected isolates had different pathogenicity when inoculated in young rabbits. 相似文献