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41.
BackgroundSeizures in the early postoperative period after intracranial surgery may affect outcome in dogs.ObjectivesTo determine the incidence of early postoperative seizures (EPS) in dogs with brain tumors, identify specific risk factors for EPS, and determine if EPS affects outcome.AnimalsEighty‐eight dogs that underwent 125 intracranial surgeries for diagnosis and treatment of rostrotentorial brain tumors.MethodsRetrospective cohort study. All patients with a diagnosis of rostrotentorial brain tumor from 2006 to 2020 were included. Early postoperative seizures were diagnosed by observation of seizure activity within 14 days of neurosurgery. Previously diagnosed structural epilepsy, perioperative anticonvulsant drug (ACD) use, magnetic resonance imaging (MRI), and tumor characteristics were evaluated. Outcome measures included neurologic and nonneurologic complications, duration of hospitalization, and survival to discharge.ResultsDogs with rostrotentorial brain tumors had EPS after 16/125 (12.8%) neurosurgical procedures (95% confidence interval [CI], 7%‐19%). Presence of previous structural epilepsy was not associated with EPS risk (P = 1). Perioperative ACD use also was not associated with EPS (P = .06). Dogs with EPS had longer hospitalization (P < .001), were more likely to have neurologic complications postsurgery (P = .01), and were less likely to survive to discharge (P = .01).Conclusions and Clinical ImportanceIt is difficult to predict which dogs are at risk of EPS because the presence of previous structural epilepsy and the use of perioperative ACDs was not associated with EPS. However, seizures in the early postoperative period are clinically important because affected dogs had prolonged hospitalization, more neurologic complications, and decreased short‐term survival.  相似文献   
42.
The effects of long-term hyperglycaemia (5 months), through feeding high levels of dietary carbohydrates, on the non-specific immunity parameters of rainbow trout, Oncorhynchus mykiss (Walbaum), was assessed. Fish were fed one of three diets composed of a basal diet containing ≈ 14% digestible carbohydrate which was progressively diluted with gelatinized potato starch in the following ratios of basal diet to supplemental carbohydrate (gelatinized potato starch): 65:00, 65:20, 65:35. The three diets were pair-fed based on the feed intake of the fish fed the diet containing the highest level of starch (65:35) and representing 100% intake. The other diets were then fed at different levels in a manner that allowed all the groups of fish in the same block to receive the same amount of the basal diet [e.g. the basal diet (undiluted, 65:00) was fed at 65% of the dietary intake of the 65:35 diet]. Blood glucose concentrations and relative liver-to-body size increased with increased dietary carbohydrate intake. Feeding supplemental carbohydrates resulted in a small increase in weight gain of the fish at both supplemental levels. Pronephros tissue lysozyme activity and pronephros macrophage superoxide production were not affected by the dietary treatments. The results suggest the presence of advanced glycosylation end-products in muscle tissue collagen, but were not significantly different between treatments. No substantial effect of long-term feeding of a high carbohydrate diet on the non-specific immunity of rainbow trout was observed. However, the results suggest that dietary carbohydrates may have a slight stimulatory effect on phagocytosis at low–moderate levels.  相似文献   
43.
Juvenile greenlip abalone, Haliotis laevigata, (mean whole weight 4.48±1.9 g, mean±s.d., n=953) were highly sensitive to ammonia as indicated by depressed growth rate and food consumption measured over 2–3 months in bioassay tanks. For growth rate expressed on a whole weight basis, the EC5 and EC50 values (5 and 50% growth reductions) were 0.041 mg FAN l−1 (Free Ammonia–Nitrogen) and 0.158 mg FAN l−1, respectively. Shell growth rates declined over the entire experimental range (0.006–0.188 mg FAN l−1). At the end of the bioassay, groups of abalone were transferred to respiratory chambers. Oxygen consumption rate increased to a maximum of 188% of control values at 0.235 mg FAN l−1 and decreased slightly at the highest concentration of 0.418 mg FAN l−1.  相似文献   
44.
Estimating the relative importance of habitat loss and fragmentation is necessary to estimate the potential benefits of specific management actions and to ensure that limited conservation resources are used efficiently. However, estimating relative effects is complicated because the two processes are highly correlated. Previous studies have used a wide variety of statistical methods to separate their effects and we speculated that the published results may have been influenced by the methods used. We used simulations to determine whether, under identical conditions, the following 7 methods generate different estimates of relative importance for realistically correlated landscape predictors: residual regression, model or variable selection, averaged coefficients from all supported models, summed Akaike weights, classical variance partitioning, hierarchical variance partitioning, and a multiple regression model with no adjustments for collinearity. We found that different methods generated different rankings of the predictors and that some metrics were strongly biased. Residual regression and variance partitioning were highly biased by correlations among predictors and the bias depended on the direction of a predictor’s effect (positive vs. negative). Our results suggest that many efforts to deal with the correlation between amount and fragmentation may have done more harm than good. If confounding effects are controlled and adequate thought is given to the ecological mechanisms behind modeled predictors, then standardized partial regression coefficients are unbiased estimates of the relative importance of amount and fragmentation, even when predictors are highly correlated.  相似文献   
45.
ABSTRACT

Effects of three supplemental calcium (Ca++; 2.5, 5.0, and 10 mole m?3) concentrations on ion accumulation, transport, selectivity, and plant growth of salt-sensitive species, Brassica rapa ‘Sani’ in saline medium were investigated. Supplemental Ca++ in the presence of 125 mol m?3 sodium chloride (NaCl) did not improve the dry weight and leaf area indicating no role played by Ca++ in the alleviation of salinity induced growth inhibition. However, calcium chloride (CaCl2) did significantly affect sodium (Na+), potassium (K+), and Ca++ contents of roots and shoots. The ion contents of shoots were significantly greater than those of roots per g dry weight, indicating ion transportation to shoots is greater than ion accumulation in roots. Use of CaCl2 in 125 mol m?3 NaCl reduced the Na+ content but increased K+ and Ca++ contents in shoots. Sodium contents in shoots differed among the supplemental Ca++ treatments indicating the role of CaCl2 in Na+ ions transportation. Calcium content in shoots declined significantly in the control treatment (0 CaCl2) but increased significantly in 10 mol m?3 CaCl2. The root also showed the effects of Ca++ on the reduction of Na+ content and the increase of K+ and Ca++ content. Unexpectedly, 5 mol m?3 CaCl2 induced the highest Na+ content in roots at 16 days after treatment. Supplemental CaCl2 application influenced the K+ or Ca++ selectivity over Na+ in two ways, ion accumulation at roots and transport to shoots. However, high CaCl2 treatments allowed greater Ca++ selectivity over Na+ than low CaCl2. Likewise, high supplemental CaCl2 showed higher K+ selectivity over Na+ than low CaCl2. A marked increase in K+ versus Na+ selectivity for the transport process occurred at 10 mol m?3 CaCl2 treatments. The roots and shoots exhibited higher K+/Na+ and Ca++/Na+ ratios in high CaCl2 treatment than in low. The results are discussed in context to supplemental Ca++ concentrations, ions accumulation, transportation and selectivity of salt sensitive Brassica rapa cultivar.  相似文献   
46.
Isotope ratio mass spectrometry and site-specific natural isotope fractionation-nuclear magnetic resonance were applied to determine the overall carbon isotope ratio (delta13C) and the hydrogen isotope ratios [(D/H)I and (D/H)II] of ethanol, respectively. Ethanol was obtained by distillation of fermented cherry mash from a pot still commonly used in fruit brandy production. Analyses of distillate fractions revealed that the distillation proceeds with a fractionation of ethanol isotopologues. The inverse vapor pressure isotope effect (VPIE) observed for the carbon isotopologues is in accordance with the data reported for distillation of ethanol in spinning band columns. In contrast, the inverse VPIE for hydrogen isotopologues of ethanol observed in spinning band columns could not be confirmed. To investigate whether the observed isotope fractionations might influence the applicability of stable isotope analysis for quality and authenticity assessment of fruit brandies, the collected distillate fractions were recombined to cuts, as is common practice in commercial fruit brandy production. Taking into consideration the limits of repeatability of the method, it could be demonstrated that the isotope fractionations observed do not impair the applicability of stable isotope analysis of the carbon and hydrogen isotopes of ethanol for the authenticity assessment of cherry brandies if the cuts are placed in accordance with common distillers' practice.  相似文献   
47.
The biosynthesis of volatile esters by Red Delicious apples was investigated by incubating fruit tissue with deuterated flavor precursors at various times after controlled atmosphere (CA) storage and measuring deuterium incorporation into branched-chain ester volatiles. 2-Methylbutyl acetate was the only volatile not significantly reduced by CA storage. Conversion of 2-methylbutanol to 2-methylbutyl acetate and of 2-methylbutanoic acid to ethyl 2-methylbutanoate and to hexyl 2-methylbutanoate was limited by the availability of 2-methylbutyl substrates but not by acetyl-CoA, ethanol, or hexanol, respectively. The enzymatic activity required for these reactions declined during CA storage. The conversion of 2-methylbutanoic acid to 2-methylbutanol was also substrate limited, but enzymic activity appeared stable in storage. Biosynthesis of both 2-methylbutanoic acid and 2-methylbutanol, from isoleucine, was severely depressed under CA storage. The reduced metabolism of isoleucine to 2-methylbutanoyl-CoA may be the primary reason for reduced branched-chain ester synthesis in CA-stored Red Delicious apples. Enantioselective gas chromatography-mass spectrometry confirmed that the chirality of (S)-2-methylbutyl acetate derives from l-isoleucine with the other enzymes in this pathway not being enantiospecific. Treatment of tissue samples with 2-methylbut-2E-enal gave only (S)-2-methylbutyl acetate, indicating that biosynthesis was not via tiglyl-CoA.  相似文献   
48.
基于田间摄像的多参数水稻土深松扰动行为与效应研究   总被引:2,自引:0,他引:2  
耕作机具的土壤扰动行为密切联系土壤失效机理与耕作效应,是优化耕作系统的重要依据。本研究通过土壤耕作原位综合测试平台开展单铲深松试验,从5个方位录制深松视频,同时配合使用微地貌测试、耕作阻力测试、EDEM仿真、深松扰动剖面土壤紧实度测试和深松理论检验,探究深松铲入土角α和耕深D对水稻土深松扰动过程、土壤失效机理及深松效应的影响。结果表明,摄像法提取的纵向碎土距离R、扰动宽度W及抬土高度H与α和D显著相关,可用于水稻土深松扰动行为的定量表述。摄像法显示水稻土难以脆性断裂,铲两侧发生非对称性土壤剪切失效。土壤沿曲柄攀升,抬土高度H随α增大,随D减小,表明深松铲的设计参数和作业参数同时影响抬土能力。R随对应耕深范围内铲的纵向水平长度L线性增加,W随α线性增加。地表平整度S和扰动宽度W均在耕深20 cm时最大。深松土壤扰动行为的EDEM仿真从微观层面再现了摄像法记录的非对称性失效、侧向挤压失效和深松新月形失效现象,表明该离散元模型用于解析水稻土深松力学的科学性。EDEM仿真进一步显示出应力集中区沿铲尖与铲柄破土刃周期性上下移动,同时也对铲下方底层土造成挤压。深松扰动剖面土壤紧实度等值线图验证了仿真过程中铲尖下方形成的土壤压实带,并直观展示出耕深30 cm时,犁底层土壤因侧向挤压流变形成的沟槽状紧实壁面。本文结合田间原位摄像法的多参数测试研究可为深松铲和耕作系统的优化提供依据。  相似文献   
49.
The characterization of herbal materials is a significant challenge to analytical chemists. Goldenseal (Hydrastis canadensis L.), which has been chosen for toxicity evaluation by NIEHS, is among the top 15 herbal supplements currently on the market and contains a complex mixture of indigenous components ranging from carbohydrates and amino acids to isoquinoline alkaloids. One key component of herbal supplement production is botanical authentication, which is also recommended prior to initiation of efficacy or toxicological studies. To evaluate material available to consumers, goldenseal root powder was obtained from three commercial suppliers and a strategy was developed for characterization and comparison that included Soxhlet extraction, HPLC, GC-MS, and LC-MS analyses. HPLC was used to determine the weight percentages of the goldenseal alkaloids berberine, hydrastine, and canadine in the various extract residues. Palmatine, an isoquinoline alkaloid native to Coptis spp. and other common goldenseal adulterants, was also quantitated using HPLC. GC-MS was used to identify non-alkaloid constituents in goldenseal root powder, whereas LC-MS was used to identify alkaloid components. After review of the characterization data, it was determined that alkaloid content was the best biomarker for goldenseal. A 20-min ambient extraction method for the determination of alkaloid content was also developed and used to analyze the commercial material. All three lots of purchased material contained goldenseal alkaloids hydrastinine, berberastine, tetrahydroberberastine, canadaline, berberine, hydrastine, and canadine. Material from a single supplier also contained palmatine, coptisine, and jatrorrhizine, thus indicating that the material was not pure goldenseal. Comparative data for three commercial sources of goldenseal root powder are presented.  相似文献   
50.
Journal of Plant Diseases and Protection - Prior to the first occurrence of chestnut blight in 1976, leaf spot caused by Cylindrosporium castaneae was one of the most important diseases of European...  相似文献   
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