A Tremor Syndrome With a Central Axonopathy in Scottish Terriers

A central axonopathy in 2 male and 1 female Scottish Terrier puppies from 3 different but related litters is reported. Clinical signs consisting of severe whole-body tremors and ataxia were first detected at the age of 10 to 12 weeks. They worsened with activity and excitement and diminished during rest or sleep. Two dogs also had paraparesis. In 1 dog the neurological deficits progressed over several months. Neuropathological examination revealed widespread axonal changes, vacuolation, and gliosis in the white matter of the central nervous system.     

Major mechanisms in formation of spodic horizons

Current explanations of the formation of spodic horizons do not accomodate all features of the horizons in their natural state. In this paper, a more complete explanation of major mechanisms is proposed, using two principles of colloid chemistry: (1) organic substances may form hydrophylic colloids with surface charges, and (2) the hydrophylic character and negative surface charges determine the dispersibility of the colloids. The hydrophylic character is due to the presence of hydrophylic radicals as parts of the organic compounds in soils. The surface charges are the result of dissociation of -COOH and possibly phenol-OH radicals.The neutralization of the surface charge can in principle occur: (1) through electrostatic or physical adsorption and (2) through chemisorption. The first case is typical for monovalent alkali cations. The adsorbed cations are distributed in a double layer, which favours dispersion. Chemisorption occurs mostly with polyvalent cations. This process corresponds in reality to the formation of organo-metallic compounds. It results in a relatively complete disappearance of the double layer and in the formation of large immobile “polymerized” organo-metallic compounds. Because these compounds contain much hydrophylic water, they form a gel. Transition into the solid state is accompanied by the loss of most of the hydration water. The dehydration may be induced by a decrease in thickness of the double layer. At a certain stage of the dehydration process, Van der Waals bonds and protonic bridges can form and bring about a certain degree of hydrophoby.In soils, mobile organic substances are formed during breakdown of plant remains. If at the top of the mineral soil enough polyvalent cations, especially Al and Fe, are available, the mobile organic substances formed are immobilized immediately and no migration occurs. In case insufficient amounts of Al and/or Fe are available to completely immobilize the mobile compounds, these cations are complexed by the mobile compounds and transported downward. Immobilization may occur at some depth through supplementary fixation of cations, through dessication or on arrival at a level with different ionic concentration.In nature, spodic horizons range from loose, with many roots, to very cemented with few roots. These differences can be related to changes in microstructure. Loose spodic horizons have a predominance of polymorphic pellets and aggregates, whereas organans or monomorphic coatings prevail in cemented horizons. The former horizons have many features suggesting major biological influences during their formation, viz., high numbers of roots, thorough mixing of the organic units with clay and silt, the presence of pedotubules and relatively young mean residence times. The latter horizons have features consistent with organo-metallic compounds immobilized in a gel-state, viz., the coatings are strongly cracked, indicating the transition of a gel into a solid; they contain much Al or Al plus Fe but very little or no Si, and the mean residence time is considerably higher than in loose horizons.The two processes seem to operate simultaneously during the formation of spodic horizons and their relative intensities determine the composition of each spodic horizon at any moment in its evolution. As long as the biological activity predominates, the horizon remains loose; if the accumulation of mobile organo-metallic compounds starts to prevail, the horizon is gradually cemented and fossilized.     

内燃机燃烧模型的发展现状

利用CFD技术对内燃机燃烧过程进行数值模拟已成为内燃机研究的重要工具。选用恰当的燃烧模型对准确预测内燃机燃烧过程具有重要意义。内燃机CFD燃烧模型主要针对自燃、预混燃烧和非预混燃烧3种燃烧模式,其中有些模型可以同时模拟2种模式或3种模式。内燃机新的燃烧系统的不断出现促进了燃烧模型的发展。本文以STAR—CD和FIRE软件为出发点,介绍了内燃机燃烧模型的发展现状。     

聚乙酸乙烯酯乳液胶的改性

本文介绍了用该改性乳液胶合的贴面胶合板的性能改性聚乙酸乙烯酯共聚乳液胶粘剂的聚合工艺，经过改性的乳液胶具有良好的耐水性，达到并超过日本二类特种合板标准，且生产工艺简单，原料易得，成本与普通乙酸乙烯酯均聚液接近,具有较强的实用性。     

Effects of nitrogen and water stress on the rehydration,endogenous hormonal regulation and yield of maize

Water scarcity is known to be a strong limiting factor affecting maize grown and yield in cold semi-arid regions. Numerous studies have shown that rehydration improves maize growth. Our study aimed to explore the effects of rehydration treatments on maize growth and yield under water and nitrogen stress during different growth stages. We selected the drought-tolerant maize variety Nendan 19 (ND19) and subjected it to water stress during the V6 (sixth-leaf), R2 (filling) and R6 (maturity) growth stages and a rehydration treatment after each stress stage. Our results indicated that N1 (N100 kg N ha⁻¹) and N3 (N300 kg N ha⁻¹) treatments significantly increased the leaf moisture status relative to water content (RWC), bound water content (BWC), free water content (FWC) and water potential (WP)) at different growth stages. Similar trends were observed in the accumulation of plant leaf and root hormones (zeatin+zeatin riboside, indole-3-acetic acid, abscisic acid and gibberellic acid), photosynthetic pigments and chlorophyll fluorescence. However, under the same water stress conditions, they decreased as the N rate increased and reached a minimum value in the S3 (water stress for N3) treatments. In addition, with growth stage advancement and extension of the rehydration time, both showed a gradual upward trend. The results showed that to save water resources in the cold semi-arid region, rehydration treatments (R2S1 and R2S3) significantly increased the photosynthetic pigments and chlorophyll fluorescence parameters, leaf moisture status, biomass, 100-grain weight, hormone content, ear characteristics and grain yield of maize.     

Field experiments to evaluate the feasibility of eradication of Aujeszky's disease virus by different vaccination schedules.

In the present report, the extent of the reduction in Aujeszky's disease virus (ADV) dissemination achieved when pigs were intensively vaccinated with gI-deleted vaccines under field circumstances, was examined. On widely dispersed breeding-fattening farms, a gI-negative status was most rapidly obtained and the rate of new waves of infections was lowest when the attenuated Bartha strain was administered to both the sows and the fatteners. It was more difficult not only to reach but also to keep a gI-negative status on farms on which the sows were vaccinated with an inactivated vaccine and the fatteners with the attenuated Bartha strain or when the fattening pigs were not vaccinated at all. In a densely populated area, 9 of the 17 farms had gI-positive fatteners at the start of the intensive vaccination programme in which the attenuated Bartha strain was given to both the sows and the fatteners. Antibodies were not detected in the sera of the fatteners of each farm at some time during the experiments, but the fatteners on 7 of the 18 farms still showed antibodies against gI after 20 months of vaccination. At the end of the experiment, the percentage of fatteners with antibodies on these farms was markedly reduced compared with the percentage at the start of the experiment. Therefore, elimination of field virus may be feasible if intensive vaccination is carried out over a sufficiently long period of time. However, the high rate of reinfections experienced either due to reintroduction of the virus or to recrudescence should be a warning against too much optimism, particularly in regions with a dense swine population.     

Oral infection with a Shiga toxin-negative Escherichia coli O157:H7 strain elicits humoral and cellular responses but does not protect sheep from colonisation with the homologous strain

We have previously shown that rectally inoculated sheep excrete Escherichia coli O157:H7 during weeks to months without developing a clear antibody response. However, antibodies against this bacterium were observed in naturally infected sheep, which most likely became orally infected. To understand this difference, sheep were orally inoculated with the same Shiga toxin-negative E. coli O157:H7 strain that was used for the rectal inoculation. A primary oral inoculation resulted in shedding of E. coli O157:H7 in the faeces and detection of antibody responses against intimin, EspA and EspB. The antibody titres waned as shedding decreased. A secondary inoculation resulted in longer shedding, even though a booster antibody response occurred. Cellular responses followed a similar pattern as the antibody levels, albeit with a lower secondary response. The presence of antigen-specific antibody-secreting cells indicates involvement of both a systemic response in the spleen and a local immune response in the terminal rectum. These results suggest that E. coli O157:H7 has to pass the small intestine to evoke antibody responses.     

Aglepristone decreases proliferation in progesterone receptor-positive canine mammary carcinomas

Background: Progesterone receptor (PR) antagonist aglepristone (RU534) has been used successfully for pregnancy termination and therapy of pyometra, vaginal tumors, and mammary hyperplasia in bitches and queens. All of these conditions share with canine mammary carcinomas the expression of PR. Objectives: To study the effect of RU534 on proliferation and apoptosis in canine mammary carcinomas in relation to PR expression. Animals: Twenty‐seven nonspayed bitches with mammary carcinomas were treated with either 2 doses of 20 mg/kg RU534 (n = 22, RU534‐treated group) or oil placebo (n = 5, control group) on days 1 and 8. Methods: Tumor samples were collected before (day 1) and after (day 15) treatment for immunohistochemistry. PR expression, proliferation index (PI), and apoptotic index (AI) were determined using antibodies against PR, Ki67, and cleaved lamin A/C antigens, respectively. The effect of treatment on these parameters was analyzed. Results: Differential expression of PR between day 1 (59.1% PR‐positive tumors) and day 15 (36.4% PR‐positive tumors) was observed in RU534‐treated tumors exclusively. After RU534 treatment, mean PI was significantly decreased in PR‐positive but unchanged in PR‐negative RU534‐treated tumors. A reduction of ≥20% in PI was found in 61.5% of RU534‐treated tumors with PR expression. Conversely, no effect on AI was observed after RU534 treatment. Conclusions and Clinical Importance: Neoadjuvant RU534 treatment had PR expression‐related inhibiting effects on proliferation of canine mammary carcinoma cells.     

Extrinsic cardiac nerve segments in the domestic dog (Canis familiaris- Linnaeus, 1758). Comparative study in young and adult dogs

In this paper, important connections between the two main contingents of the autonomic nervous system, intrinsic and extrinsic visceral plexus were analysed. Concerning heart innervation, the territories of extrinsic innervation are very important in the treatment of congenital or acquired cardiopathy, thoracic neoplasia and aortic arch persistence, among others. This research compared young and adult extrinsic cardiac innervation and described the surgical anatomic nerve segments. Animals were perfused with a 10% formaldehyde solution in PBS (0.1 m) (pH 7.4) and submitted to macro- and meso-scopic dissection immersed in 60% acetic acid alcoholic solution and 20% hydrogen peroxide aqueous solution. The nerve segments were assigned as: right vagus nerve segment, left vagus nerve segment, right middle cervical ganglion segment, left middle cervical ganglion segment, right caudal laryngeal nerve segment, left caudal laryngeal nerve segment, right phrenic nerve segment and left phrenic nerve segment.