Multi-element analysis of South African wines by ICP-MS and their classification according to geographical origin   总被引：5，自引：0，他引：5  

Coetzee PP  Steffens FE  Eiselen RJ  Augustyn OP  Balcaen L  Vanhaecke F 《Journal of agricultural and food chemistry》2005,53(13):5060-5066

Wines from three important wine-producing regions, Stellenbosch, Robertson, and Swartland, in the Western Cape Province of South Africa, were analyzed by ICP-MS and the elemental composition used in multivariate statistical analysis to classify the wines according to geographical origin. The method is based on the assumption that the provenance soil is an important contributor to the trace element composition of a wine. A total of 40 elements were determined in 40 wines. Of these, 20 elements: Li, B, Mg, Al, Si, Cl, Sc, Mn, Ni, Ga, Se, Rb, Sr, Nb, Cs, Ba, La, W, Tl, and U showed differences in their means across the three areas. In a stepwise discriminant analysis procedure, functions based on linear combinations of the log-transformed element concentrations of Al, Mn, Rb, Ba, W, and Tl were generated to correctly classify wines from each region. In an alternative approach, a pairwise discriminant analysis procedure, not previously used in wine provenance studies, was tested. In this procedure, the classification was done in three steps, with each step classifying a wine as coming from a certain region or not. The combination of elements characterizing wines from a particular region was different in each region. The discriminant functions were based on the following elements: Al, Mn, Rb, Ba, and W for Stellenbosch; Se, Rb, Cs, and Tl for Robertson; and Al, Mn, Rb, Sr, Ba, and Tl for Swartland. After this procedure, the classification of the wines into one of the groups was 100% successful.  相似文献   

精原干细胞及其在转基因技术中的应用     

Virginie Olive  Francois Cuzin  刘吉宏 《国外畜牧学(猪与禽)》2007,27(1):28-31

睾丸内生殖细胞分化起源于不断更新的干细胞小池,继而首先引起生精细胞(精原细胞)分化。这些定型细胞然后遵循一个固定的程序进行演化,它们首先同步化地进行六次有丝分裂,然后进入第一次减数分裂期。以形态学和细胞学标准,鉴别精原干细胞,根据注入不育者睾丸的分化活力,进行功能检测。目前干细胞的纯化和鉴定研究取得了日新月异的发展。生殖系生物学基本理论和多个领域中的临床前研究将会从中得益,同时附植前的基因转移为转基因技术开辟一条崭新的途径。细胞特征:①源于初生睾丸生长捕获生殖母细胞的少量精原干细胞(2～3×104/成年睾丸),主要分布在生精小管的周围;②细胞遗传学分析首次鉴定表明,它们是缺乏异染色质的圆形小细胞;③通过移植入缺乏生殖细胞的受体睾丸,在功能上表现为具有重建永久精子发生的能力;④基于α6β1整合素和CD9表达,可以获得较高浓度的精原干细胞,在转基因启动子驱动下异源表面蛋白质得以表达,可进一步纯化产物;⑤逆转录病毒载体能使基因转移先于移植,转基因后代随后即可产生。  相似文献   

Planetary science. Alien weather at the poles of Mars     

Forget F 《Science (New York, N.Y.)》2004,306(5700):1298-1299

  相似文献   

Patterns of exotic plant invasions in fragmented urban and rural grasslands across continents     

Sarel S. Cilliers  Nicholas S. G. Williams  Francois J. Barnard 《Landscape Ecology》2008,23(10):1243-1256

Linear native grassland remnants in fragmented landscapes are usually at a great risk of exotic species invasion from their edges. Changes in species distribution near habitat edges are extensively studied in ecology as knowledge about edge responses is important to understand the development of patterns and processes in landscapes. However, elucidating robust general principles for edge effects has been difficult as species responses to habitat edges are highly variable and dependent on a large number of attributes which affect the function and structure of edges and therefore the distance that edge effects penetrate into fragmented natural vegetation. The objective of this study was to investigate the generality of exotic species invasion patterns from edges in native grassland patches surrounded by urban and rural landscapes. This was done by comparing the results of research from Victoria, Australia with a similar study from North-West Province, South Africa. Despite their occurrence on different continents, the grasslands are floristically and structurally similar and are dominated by the same grass species. Invasion patterns were quantified using two spatial statistics methods; block kriging and spatially constrained clustering. Two distinct patterns of exotic species invasion were identified in native grassland remnants in South Africa and Australia, namely exotic species invasion from the edge where the cover of exotic species increased with increasing proximity to the edge and a pattern that suggests that gap phase vegetation dynamics may also drive exotic species invasion at urban grasslands. Although urbanization and weed invasions are complex processes similar patterns of exotic species invasion in urban grasslands were found in two different continents suggesting that general patterns may occur. Implications of this for the conservation of native grasslands in contrasting landscapes are discussed.  相似文献   

欧洲现代木结构建筑不同的构造技术和成本分析     

施煜庭  王煜华  周定国 《林产工业》2011,38(1)

木材是一种可再生的、同时也是最古老的建筑材料之一。由于其天然美观的纹理、柔和的视觉效果、良好的保温隔热性能以及优良的力学性能,自上古时期的构木为巢开始就和人类生活息息相关,木结构建筑是人类最早兴建的建筑结构之一,积淀着丰厚的建筑文明传统。1欧洲现代木结构建筑发展概况建筑的发展史就是一部科学技术的发展史。技术手段的变革会超越风格流派等文化因素直接对建筑设计产生巨大的影响,并使得设计师的创作观念及设计方法也随之发生变化。这  相似文献   

The consequences of late outbreaks of the aphid Aphis gossypii in cotton growing in central Africa: Towards a possible method for the prevention of cotton stickiness     

Jean-Philippe Deguine  Eric Goze  Francois Leclant 《国际虫害防治杂志》2013,59(2):85-89

'Sticky cotton' causes substantial economic loss in central Africa. The phenomenon is the result of honeydew excreted by sapsucking insects, mainly the aphid Aphis gossypii Glover. The chemical protection currently available to farmers does not limit this type of damage effectively. From exhaustive counting of infested leaves and quantitative measurement of stickiness with a thermodetector, a positive relationship can be established between the seriousness of fibre stickiness and aphid outbreaks at the end of the season. A control method involving the topping of plants after boll opening reduces the number of leaves on which aphids feed and thus the abundance of the aphids.  相似文献   

气味指纹分析技术在食品质控和风味研究的应用   总被引：4，自引：0，他引：4  

朱丽敏  倪元颖  Soffy Venzal  Francois Soffys 《农产品加工．学刊》2005,(Z2)

着重以食用油、橙汁和奶制品为例,阐述了SensoryArrayFingerprinAtnalyzerMethod(气味指纹分析法)对食品所建立的新型质量控制和风味研究方法。经针对7种储存时间不同的食用油、脂(大豆油、菜籽油、猪油、牛脂、禽类脂、白色油脂、棕榈油)的过氧化值和酸价的分析模型的建立,展示了应用气味指纹分析技术(电子鼻)对食用油品质控制及抗氧化能力比较的新方法,对不同品质的橙汁(半年和一年半的鲜榨汁,和浓缩还原汁)、不同种类的鲜奶(灭菌全脂奶、灭菌半脱脂奶、半脱脂生奶和乳粉还原奶)和真伪某品牌奶粉的区分,表明该技术对复杂介质样品的品质变化具有独特的识别能力。分析结果表明,该分析技术具有以下优点:满意的分析灵敏度和重复性:传感器检测平均重复性为1.32%RSD(n=10),对同一样品测量的重复性为1.4%RSD(n=10),对所有油样的过氧化值和酸价测定具有良好的线性关系,平均相关系数为0.9984。不同品质样品之间区分指数DI的特异性明显(>90)。所有的数据通过化学计量学方法处理,并且该分析方法无需样品前处理。  相似文献   

Leaf volatile compounds of seven citrus somatic tetraploid hybrids sharing willow leaf mandarin (Citrus deliciosa Ten.) as their common parent     

Gancel AL  Ollitrault P  Froelicher Y  Tomi F  Jacquemond C  Luro F  Brillouet JM 《Journal of agricultural and food chemistry》2003,51(20):6006-6013

Volatile compounds were extracted by a pentane/ether (1:1) mixture from the leaves of seven citrus somatic tetraploid hybrids sharing mandarin as their common parent and having lime, Eurêka lemon, lac lemon, sweet orange, grapefruit, kumquat, or poncirus as the other parent. Extracts were examined by GC-MS and compared with those of their respective parents. All hybrids were like their mandarin parent, and unlike their nonmandarin parents, in being unable to synthesize monoterpene aldehydes and alcohols. The hybrids did retain the ability, although strongly reduced, of their nonmandarin parents to synthesize sesquiterpene hydrocarbons, alcohols, and aldehydes. These results suggest that complex forms of dominance in the mandarin genome determine the biosynthesis pathways of volatile compounds in tetraploid hybrids. A down-regulation of the biosynthesis of methyl N-methylanthranilate, a mandarin-specific compound, originates from the genomes of the nonmandarin parents. Statistical analyses showed that all of the hybrids were similar to their common mandarin parent in the relative composition of their volatile compounds.  相似文献   

Assessment of earthworm contribution to soil hydrology: a laboratory method to measure water diffusion through burrow walls     

Francois Bastardie  Stéphane Ruy  Daniel Cluzeau 《Biology and Fertility of Soils》2005,41(2):124-128

The capacity for water diffusion in burrow walls (i.e. the coefficient of sorptivity) either burrowed by Lumbricus terrestris (T-Worm) or artificially created (T-Artificial) was studied through an experimental design in a 2D terrarium. In addition, the soil density of earthworm casts, burrow walls (0–3 mm around the burrow) and the surrounding soil (>3 mm) were measured using the method of petroleum immersion. This study demonstrated that the quantity of water which transits through burrows of L. terrestris in the soil matrix was lower than that transited through soil fractures, due to a reduction of soil porosity in burrow walls (compaction: cast > worms burrow walls > surrounding soil > artificial burrow walls). Earthworm behaviour, in particular burrow reuse with associated cast pressing on walls, could explain the larger burrow wall compaction in earthworm burrows. If water diffusion was lower through the compacted burrows, burrow reuse by the worms makes them more stable (worms would maintain the structure over years) than unused burrows. The present experimental design could be used to test and measure the specific differences between earthworm species in their contributions to water diffusion. Probably, these contributions depend on the presumed related-species behaviours which would determine the degree of burrow wall compaction.  相似文献   

Uptake and metabolic fate of [14C]-2,4-dichlorophenol and [14C]-2,4-dichloroaniline in wheat (Triticum aestivum) and soybean (Glycine max)   总被引：1，自引：0，他引：1  

Pascal-Lorber S  Rathahao E  Cravedi JP  Laurent F 《Journal of agricultural and food chemistry》2003,51(16):4712-4718

The uptake and metabolism of [14C]-2,4-dichlorophenol (DCP) and [14C]-2,4-dichloroaniline (DCA) were investigated in wheat and soybean. Seeds were exposed to a nutrient solution containing 50 microM of one of two radiolabeled compounds, and plant organs were harvested separately after 18 days of growth. In wheat, uptake of [14C]-2,4-DCP was 16.67 +/- 2.65 and 15.50 +/- 2.60% of [14C]-2,4-DCA. In soybean, uptake of [14C]-2,4-DCP was significantly higher than [14C]-2,4-DCA uptake, 38.39 +/- 2.56 and 18.98 +/- 1.64%, respectively. In the case of [14C]-2,4-DCP, the radioactivity absorbed by both species was found mainly associated with roots, whereas [14C]-2,4-DCA and related metabolites were associated with aerial parts, especially in soybean. In wheat, nonextractable residues represented 7.8 and 8.7% of the applied radioactivity in the case of [14C]-2,4-DCP and [14C]-2,4-DCA, respectively. In soybean, nonextractable residues amounted to 11.8 and 5.8% of the total radioactivity for [14C]-2,4-DCP and [14C]-2,4-DCA, respectively. In wheat, nonextractable residues were nearly equivalent to extractable residues for [14C]-2,4-DCP, whereas they were greater for [14C]-2,4-DCA. In soybean, the amount of extractable residues was significantly greater for both chemicals. However, in both species, nonextractable residues were mainly associated with roots. Isolation of soluble residues was next undertaken using excised shoots (wheat) or excised fully expanded leaves including petioles (soybean). Identification of metabolite structures was made by comparison with authentic standards, by enzymatic hydrolyses, and by electrospray ionization-mass spectrometric analyses. Both plant species shared a common metabolism for [14C]-2,4-DCP and [14C]-2,4-DCA since the malonylated glucoside conjugates were found as the final major metabolites.  相似文献