禽流感病毒抗原超滤浓缩重要参数的动态变化

采用世界先进的切向流超滤浓缩技术，对禽流感病毒（H9N2亚型）超滤浓缩成倍体积，测定血凝价HA和半数感染量EID50。结果HA成倍增加，废液HA呈阴性，病毒回收率达100％；受宿主鸡胚系统的影响，EID50与病毒量之间不是简单的直线关系，但病毒的活性不受影响。结果表明，所用超滤系统适用于禽流感病毒抗原的浓缩。     

Community forestry for revitalising rural ecosystems: A case study

A case study focusing on the socio-economic and ecological aspects of a forest-based village, Debrasai, in the Singhbhum District of Bihar, India was undertaken in 1980 to evolve village-specific community forestry package programmes that could bring stability to the village both economically as well as ecologically. The village extending over 365.07 ha is inhabited by 361 people comprising 195 males and 166 females in 81 households. The villagers are by and large dependent on agriculture and forestry for their livelihood. The largest proportion of the land in the village is under agriculture whereas forests, in a highly degraded state, occupy only 5.7% of the total area. The villagers exploit the protected forests in their vicinity removing nearly 350.9 mt of fuelwood, 22.8 mt of small timber and 393.4 mt of fodder annually.The village has a manpower potential of 40 035 man days a year. Agriculture is the main source of employment at the moment absorbing 14 266 man days. The non-agricultural sector provides employment to an extent of 4433 man days. Fresh employment opportunities are needed to absorb nearly 53% of man days of the village at present unused. Three land-resource, skill-based package programmes, a tasar silk culture, an energy plantation, and dairying have been suggested to generate employment opportunities and to meet the basic needs of the villagers. About 115 ha of the hitherto neglected land resource has been located in the village to sustain such community forestry (CF) programmes. Tasar culture suggested on 35 ha will alone generate employment to an extent of 18 690 man days from the fourth year of tasar silk plantation. A plantation, to provide energy and fodder, on 25 and 30 ha respectively is expected to yield fuelwood, timber and fodder to more than satisfy village needs. A dairy has been recommended as it will generate income, provide nutrition and promote gobar gas production — an alternative energy source to fuelwood. The cost—benefit analysis of these projects indicates their economic feasibility with the cost likely to be recovered in 4.5 years. Debrasai being an agricultural village, a land-inequity compensatory scheme has been suggested for CF project net benefit sharing, ensuring reasonable benefit flows to the landless and marginal farmers.     

Body development, carcass, and meat quality of confined lambs fed increasing levels of whole rice meal

The objective of this trial was to evaluate the effect of whole rice meal (WRM) inclusion in the concentrate upon body development, carcass traits, and meat quality of lambs. Twenty-four castrated lambs with an average initial body weight of 17.90?±?2.72 kg were randomly blocked according to two genetic groups (Corriedale and Texel by Corriedale crossbreds). Three isocaloric (11.3 MJ/kg of metabolizable energy) and isonitrogenous (17 % crude protein) diets were offered to the animals for 74 days. Diets consisted of 40 % forage and 60 % concentrate diet, on a dry matter basis, with 0, 15, or 30 % of WRM inclusion into the concentrate. Body growth (after slaughter), carcass, and meat traits were evaluated on each animal. Results obtained indicated that genotype did not affect body growth, carcass, and meat traits except for yellowness. No significant interaction between diet and genotype were detected. Inclusion of up to 30 % WRM did not significantly (P?>?0.05) affect body growth, carcass, and meat traits, except for meat color. Meat luminosity progressively increased (36.32?+?0.055X) while redness (15.13???0.03X) decreased with the inclusion of WRM in the diet, but still remained within acceptable values. The study indicates that WRM may be included up to 30 % in the concentrate replacing corn without adverse effects upon body development, carcass traits, and meat quality of lambs.     

Method for estimation of ocean current velocity from satellite images

Barotropic instability waves on a shear interface propagate at the average speed of the water on the two sides. Assuming the instability to be excited by tidal oscillations, the phase speed is the wavelength divided by the tidal period. If the water is at rest on one side of the shear layer the current speed on the other side can be calculated. This method, applied to the Gulf Stream beyond Cape Hatteras as seen in satellite images, gives estimates of current speed in general agreement with in situ observations.     

Crystal structure analysis of deamino-oxytocin: conformational flexibility and receptor binding

Two crystal structures of deamino-oxytocin have been determined at better than 1.1A resolution from isomorphous replacement and anomalous scattering x-ray measurements. In each of two crystal forms there are two closely related conformers with disulfide bridges of different chirality, which may be important in receptor recognition and activation.     

Possible parachordoma in a dog

Abstract

CASE HISTORY: A 15-mm diameter mass developed in the S/C tissue overlying the right lateral gluteal muscle of a 6½-year-old female Flat-coated Retriever.

PATHOLOGICAL FINDINGS: Cytological preparations following aspiration of the mass were highly cellular and consisted of a population of large polygonal cells containing single to multiple nuclei, large prominent nucleoli, and intracytoplasmic vacuoles. Histologically, the neoplasm consisted of similar large cells surrounded by thick fibrous connective tissue trabeculae. The large polygonal cells reacted positively with antibodies against vimentin, low- and high-molecular-weight variants of cytokeratin (AE1/AE3), but not with antibodies to desmin or glial fibrillary acidic protein (GFAP).

DIAGNOSIS: The clinical, gross, histological and immunohistochemical findings are similar to those reported for parachordomas in humans. Neither recurrence nor metastases were noted 18 months after surgical excision of the mass.

CLINICAL RELEVANCE: This is the first reported case of a possible parachordoma in a dog, a benign tumour with cytological features of malignancy.     

Powassan virus,a scoping review of the global evidence

Background

Powassan virus (POWV), a flavivirus discovered in 1958, causes sporadic but severe cases of encephalitis in humans. Since 2007, the number of human Powassan cases diagnosed each year in the USA has steadily increased. This is in agreement with predictions that Powassan cases may increase in North America as a result of increased exposure to infected ticks. However, the increase may also reflect improved diagnostics and reporting among other factors.

Methods

A scoping review was prioritized to identify and characterize the global literature on POWV. Following an a priori developed protocol, a comprehensive search strategy was implemented. Two reviewers screened titles and abstracts for relevant research and the identified full papers were used to characterize the POWV literature using a predetermined data characterization tool.

Results

One hundred and seventy‐eight articles were included. The majority of the studies were conducted in North America (88.2%) between 1958 and 2017. Both genotypes of POWV (Powassan lineage 1 and Deer Tick virus) were isolated or studied in vitro, in vectors, nonhuman hosts and human populations. To date, POWV has been reported in 147 humans in North America. The virus has also been isolated from five tick species, and several animals have tested positive for exposure to the virus. The relevant articles identified in this review cover the following eight topics: epidemiology (123 studies), pathogenesis (66), surveillance (33), virus characterization (22), POWV transmission (8), diagnostic test accuracy (8), treatment (4) and mitigation strategies (3).

Conclusion

The literature on POWV is relatively small compared with other vector‐borne diseases, likely because POWV has not been prioritized due to the small number of severe sporadic human cases. With the projected impact of climate change on tick populations, increases in the number of human cases are expected. It is recommended that future research efforts focus on closing some of the important knowledge gaps identified in this scoping review.     

Leucocyte profile and growth rates as indicators of crowding stress in pejerrey fingerlings (Odontesthes bonariensis)

Crowding is one of the most common stressors found in intensive aquaculture, compromising growth rates and immune function. Plasmatic cortisol is a classic stress biomarker for fish, but its quantification is expensive and demands blood volumes that small individuals do not provide, constraining the usage of this technique to assess stress in fingerlings. The leucocyte profile is an alternative methodology to quantify stress with reduced costs and volumes of blood. Stress conditions promote neutrophilia and lymphocytopenia as response to elevated glucocorticoids levels. Considering the difficulties to assess stress imposed by intensive fish farming using measurement of glucocorticoid hormones, this study aimed to evaluate the stress‐induced changes in leucocyte profiles and growth rates imposed by crowding in fingerlings of Odontesthes bonariensis, a promising South‐American candidate for freshwater aquaculture. To meet these objectives, fingerlings (initial weight 0.05 ± 0.06 g and length 1.68 ± 0.13 cm) were reared for 45 days under three rearing densities (1, 5 and 10 fingerlings L^?1). At the end of this period, fish were anaesthetized and euthanized to obtain the leucocyte profile, neutrophil:lymphocyte ratio (N:L) and growth rate. Increasing density promoted: significant reduction in growth (final length, weight and specific growth rate); neutrophilia and lymphocytopenia; and increased N:L ratio. Concluding, the tested rearing densities imposed distinct levels of stress characterized by different N:L ratio, demonstrating that the leucocyte profile is a reliable alternative to measure stress levels in O. bonariensis fingerlings and probably in other fish species.     

Improvement of Fertility in Artificially Inseminated Ewes Following Vaginal Treatment with Misoprostol Plus Terbutaline Sulphate

The effect of vaginal administration of misoprostol plus terbutaline sulphate 6 h prior to artificial insemination (AI) upon the site of AI (vaginal or cervical) and fertility was studied using a total of 87 estrous synchronized Serra da Estrela ewes (control n = 42 and treated n = 45). Artificial insemination was performed using refrigerated semen at 54–55 h after sponge removal. Lambing rate (fertility) and prolificacy were compared between control and treated ewes. The effect of the site of semen deposition on fertility was also evaluated. Prolificacy rate was not different between control (1.5) and treated (1.59) ewes. The proportion of cervical AI achieved in control (45.2%) and treated (37.8%) ewes was not significantly different. Overall, fertility was significantly lower in control than in treated ewes (42.9% vs 64.4%; p < 0.04). Fertility following vaginal AI was significantly lower for control for than treated ewes (30.4% vs 60.7%; p < 0.03) but the difference was smaller and not significant for cervical AI (control 57.9% vs 70.6%). It was concluded that vaginal administration of misoprostol plus terbutaline sulphate 6 h prior to artificial insemination did not affect the proportion of cervical inseminations but significantly improved the fertility of treated ewes. Although needing confirmation, it was hypothesized that drugs might have induced local secretory modifications leading to an increase of cervical ability to retain more viable spermatozoa for fertilization.