Pharmacokinetic behaviour of enrofloxacin and its metabolite ciprofloxacin after subcutaneous administration in cattle

This study compared pharmacokinetic profiles in cattle dosed subcutaneously with two different formulations of enrofloxacin (5% and 10%) at a dose of 5 mg/kg. Plasma concentrations of enrofloxacin and its active metabolite, ciprofloxacin, were determined by a HPLC/u.v. method. The pharmacokinetic parameters of enrofloxacin and its metabolite were similar in both injectable formulations. Enrofloxacin peak plasma concentration (5%: 0.73 ± 0.32; 10%: 0.60 ± 0.14 μg/mL) was reached at 1.21 ± 0.52 and 1.38 ± 0.52 h to 5 and 10%, respectively. The terminal half-live and area under curve were 2.34 ± 0.46 and 2.59 ± 0.46 h, and 3.09 ± 0.81 and 2.93 ± 0.58 μg·h/mL, to 5 and 10%, respectively. The AUC/MIC₉₀ and Cmax/MIC₉₀ ratios for both formulations exceed the proposed threshold values for optimized efficacy and minimized resistance development whilst treating infections or septicaemia caused by P. multocida and E. coli.     

南美洲安第斯山块茎美洲落葵引种评价

美洲落葵为南美安第斯地区的一类块茎作物,以从国际马铃薯中心引进7个生态型的试管苗为试验材料,通过组培快繁形成一定的栽种.在此基础上,通过在昆明的大棚品种栽培比较,在昆明、石林、丽江三地的露地栽培对比以及在丽江的大棚、露地栽培对比,选择出在云南大棚栽培及露地栽培的适应品种(生态型),结果表明U5、U7较适合大棚栽培,U5、U6、U7较适合露地栽培.试验结果还表明,不同地区的栽培对植物生长及产量有影响,但对美洲落葵的营养成分几乎没有影响.     

丘陵地区城乡建设用地增减挂钩潜力分析— — —以重庆市北碚区为例

城镇建设造成的耕地减少、农村居民点闲置现象并存,对城乡建设用地增减"挂钩"提出了现实要求.相关研究对"挂钩"的由来、概念,挂钩的各种阻力、挂钩的落实方法及挂钩中的权属问题做了大量研究,但在挂钩的潜力研究方面,已有的研究大多基于宏观预测数据,很少考虑到乡镇内部条件及居民点分布特征的差异.为此,本文以北碚区为例考虑自然条件、社会经济发展、居住形态等因素的综合影响,综合测算丘陵地区的"挂钩"潜力.     

Validation of single‐step GBLUP genomic predictions from threshold models using the linear regression method: An application in chicken mortality

The objective of this study was to determine whether the linear regression (LR) method could be used to validate genomic threshold models. Statistics for the LR method were computed from estimated breeding values (EBVs) using the whole and truncated data sets with variances from the reference and validation populations. The method was tested using simulated and real chicken data sets. The simulated data set included 10 generations of 4,500 birds each; genotypes were available for the last three generations. Each animal was assigned a continuous trait, which was converted to a binary score assuming an incidence of failure of 7%. The real data set included the survival status of 186,596 broilers (mortality rate equal to 7.2%) and genotypes of 18,047 birds. Both data sets were analysed using best linear unbiased predictor (BLUP) or single‐step GBLUP (ssGBLUP). The whole data set included all phenotypes available, whereas in the partial data set, phenotypes of the most recent generation were removed. In the simulated data set, the accuracies based on the LR formulas were 0.45 for BLUP and 0.76 for ssGBLUP, whereas the correlations between true breeding values and EBVs (i.e. true accuracies) were 0.37 and 0.65, respectively. The gain in accuracy by adding genomic information was overestimated by 0.09 when using the LR method compared to the true increase in accuracy. However, when the estimated ratio between the additive variance computed based on pedigree only and on pedigree and genomic information was considered, the difference between true and estimated gain was <0.02. Accuracies of BLUP and ssGBLUP with the real data set were 0.41 and 0.47, respectively. This small improvement in accuracy when using ssGBLUP with the real data set was due to population structure and lower heritability. The LR method is a useful tool for estimating improvements in accuracy of EBVs due to the inclusion of genomic information when traditional validation methods as k‐fold validation and predictive ability are not applicable.     

316L不锈钢在模拟含二氧化碳原油中的耐腐蚀性能

为了进一步掌握316L不锈钢的适应性,以试验点CO₂驱油后采出介质为主要溶液,采用高温高压反应釜,对316L不锈钢挂片的腐蚀规律进行了研究。以Cl-质量浓度、Ca2+质量浓度、CO₂分压、温度、流速及油水比作为影响因素开展试验,并利用电子显微镜和电化学工作站对试验范围内腐蚀速率最高的挂片形貌和电化学腐蚀特征进行观察分析。试验结果表明:在Cl-质量浓度为3 000～50 000 mg/L、Ca2+质量浓度为100～6 000 mg/L、CO₂分压为0.15～0.75 MPa、温度为15～55℃、流速为0～0.5 m/s以及20%、85%两种含水率条件下,316L不锈钢的腐蚀速率均在10-3～10-2 mm/a数量级之间变化。通过电镜扫描和能谱分析发现,试件中耐腐蚀元素Mo的质量分数略高于最低限,在Al杂质较多的部位,316L不锈钢出现了腐蚀轻微的开口型点蚀坑,表明316L不锈钢在试验范围内具有很好的耐全面腐蚀能力,但点蚀问题不能忽视,试验用316L不锈钢中Cr、Ni、Mo的质量分数均略微高于最低限,建议在选材过程中对有利微...     

Waterlogging Affects Leaf and Tillering Dynamics in Wheat and Barley

The aim of this study was to analyse (i) the crop attributes that determine flowering time (i.e. final leaf number, FLN; and phyllochron, Phy), (ii) the dynamics of tiller appearance and (iii) the synchrony between leaf and tiller appearance in wheat and barley plants exposed to waterlogging. Two experiments were carried out in pots, in which wheat and barley cultivars were exposed to five waterlogging treatments, during different periods throughout the crop cycle, from emergence to maturity. The appearance of leaves and tillers on the main stem was measured twice a week in labelled plants. Waterlogging from emergence to flag leaf appearance significantly delayed time to flowering. The delay was greater when waterlogging occurred at the beginning of tillering, lengthening the period from emergence to flowering 24 % (13–15 days) in barley and 10–15 % (6–10 days) in wheat, as compared to control. Phy was the main attribute explaining the delay in flowering, as FLN was not altered. Waterlogging during the early stages of development reduced tiller appearance rate (TAR) in both species, but this effect was partially counterbalanced by a lengthening of the tillering phase, so the effect on final tiller number at maturity was limited. In conclusion, the exposure of wheat and barley to waterlogging during early stages of development delayed time to flowering and reduce TAR in both species. Waterlogging during more advanced crop stages produced slight effects on tillering dynamics, which would indicate that waterlogging affected structure generation more than mortality.     

Biogeochemistry of a Hyperacidic and Ultraconcentrated Pyrite Leachate in San Telmo mine (Iberian Pyrite Belt, Spain)

This work describes recent research carried out in an extremely acidic (pH 0.61–0.82) and hypersaline (e.g., 134 g/L SO₄ ^2-, 74 g/L Fe, 7.5 g/L Al, 3 g/L Mg, 2 g/L Cu, 1 g/L Zn) leachate which seeps from a pyrite pile in San Telmo mine (Huelva, SW Spain) and forms evaporative pools of ultra-concentrated water in which attractive crystals of Zn-rich melanterite (Fe^IISO₄ 7H₂O) are formed. Geochemical modeling with the Pitzer method indicates that the acidic brine was near saturation with respect to melanterite (SI_Mel?=?0?±?0.2). The microbiological investigation has revealed a surprisingly high biomass (1.4?×?10⁶ cells mL^?1) and an exotic ecosystem composed of acidophilic, Fe-oxidizing archaea (mainly Ferroplasma spp., representing 52% of the microbial population), and minor numbers of acidophilic bacteria (including Leptospirillum spp. (3.2%), Acidithiobacillus spp. (1.6%), and Alphaproteobacteria (2.8%)). The microbial production of Fe^III allows the oxidative dissolution of pyrite and other sulphides, which results in additional inputs of Fe^II, SO₄ ^2- and acidity to the system. The surfaces of the pyrite crystals show a typical etch-pitted texture, as well as blobs of elemental sulphur, which are both compatible with this indirect, microbially mediated oxidation mechanism. The composition of the acidic leachate seems to result from the combination of several processes which include: (1) formation of melanterite within the pile during relatively dry seasons, (2) subsequent dissolution of melanterite during rainy episodes, (3) microbial oxidation of Fe^II, (4) sulphide oxidation mediated by Fe^III, (5) dissolution of chlorite and other aluminosilicates present in the pile, and (6) cooling and/or evaporation of seepage from the pile and consequent melanterite precipitation.     

Incidence of group A and atypical rotaviruses in Brazilian pig herds

The incidence of rotaviruses as a gastroenteritis causal agent in piglets was studied in 19 pig herds of Sao Paulo State, Brazil, during 1985. From 302 diarrhoea samples collected during January (summer), 65 were positive for rotavirus when analysed by enzyme-linked immunosorbent assay (ELISA) and polyacrylamide gel electrophoresis (PAGE). Sixty-two of these samples belonged to the classical group A rotavirus, three to atypical rotaviruses (ELISA negative and probably group B) and one elicited a mixed electropherotype of group A and atypical rotavirus and was ELISA positive. Atypical viruses appear to be very fragile and were rapidly degraded upon storage of samples at -20 degrees C. Three herds where atypical rotaviruses were present in January were sampled again in August (winter). Nine atypical isolates out of a total 21 positive samples (assayed by electron microscopy and PAGE) were detected again in two of them.     

陕西省杨陵区鸡球虫病原种类的调查研究

对杨陵区四乡一镇的６８组鸡群进行了鸡球虫病的调查研究。结果表明,杨陵区鸡球虫病比较普遍,１５￣５０日龄雏鸡的球虫病特别严重。全区鸡的球虫平均感染率为５８．３％,在所检查的青年,成年鸡群中,笼养鸡群的球虫感染率为３５．１％,散养鸡群的球虫感染率为５７．４％。雏鸡的球虫感染率为６８．４％。经实验室鉴定,共查见柔嫩艾美耳球虫,毒害艾美耳球虫,巨型艾美耳球虫,堆型艾美耳球虫和缓艾美耳球虫和哈氏艾美耳球虫等     

Key issues and challenges in whole wheat flour milling and storage

Whole wheat flour is increasingly popular as research continues to reveal the benefits of whole grains and the food industry offers more whole grain options for consumers. The purpose of this review is to address milling and shelf-life issues that are unique to whole wheat flour. No standard methods are available for whole wheat flour milling, resulting in very different bran particle sizes. Literature suggests that moderate bran particle size is the best for bread production, while small particle size is better for non-gluten applications. Shelf-life of whole wheat flour is shorter compared to white flour due to the presence of lipids and lipid-degrading enzymes. Lipolytic degradation leads to reduction in functionality, palatability and nutritional properties. Strategies to stabilize whole wheat flour have focused on controlling lipolytic enzyme activity and have marginally succeeded.