976 resultados para 28-271
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对 Ni6 9.5Al2 8Y2 .5粉末进行球磨 ,获得 Ni Al金属间化合物 .研究粉末结构与球磨时间的关系 ,探索以中间合金的形式加入稀土元素的机械合金化方法 .结果表明 ,加入稀土元素后 ,用机械合金化的方法可以生成新的金属间化合物.
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系统研究了2-乙基已氧基甲基膦酸工(2-乙基已基)酯(代号PT-28)在硝酸介质中萃取三价镧系元素的行为,讨论了萃取剂浓度的变化、硝酸钠的浓度及温度变化对萃取率的影响,并对PT-28. 萃取HNO_3的机理进行了探讨。
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The extracts obtained from 28 species of marine algae were evaluated for their antioxidant activity (AA) versus the positive controls butylated hydroxytoluene (BHT), gallic acid (GA), and ascorbic acid (AscA). Most of the tested samples displayed antioxidant activity to various degrees. Among them, the extract of Symphyocladia latiuscula exhibited the strongest AA, which was comparable to BHT, GA, and AscA in radical scavenging activity, as shown in the DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl) assay, and higher than those of the positive controls in beta-carotene-linoleate assay system. In addition, the ethyl acetate-soluble fraction isolated from the crude extract of S. latiuscula exhibited the highest antioxidant activity in both assay systems. This fraction was further fractionated into seven subfractions (F1-F7) by vacuum liquid chromatography (VLC). F1 and F4 were found to be the most effective subfractions in scavenging DPPH radical assay and in the beta-carotene-linoleate assay, respectively. The total phenolic content (TPC) and reducing power (RP) for all of the extracts, fractions, and subfractions (F1-F7) were also determined. The TPC of the 28 extracts ranged from 0.10 to 8.00 gallic acid equivalents (mg/g seaweed dry weight) while the RP ranged from 0.07 to 11.60 ascorbic acid equivalents (mg center dot g(-1) seaweed dry weight). Highly positive relationships between AA and TPC as well as between AA and RP were found for the extracts and fractions, while for the subfractions F1-F7 only weak or no such relations were found. The results obtained from this study indicate that further analysis is needed of those marine algal species that contain the most antioxidant activity in order to identify the active principles.
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第一部分 刺参遗传连锁图谱的构建 利用AFLP和微卫星标记以一个远缘地理杂交家系为作图群体,以拟测交理论为作图策略,构建了刺参Apostichopus japonicus的雌性和雄性遗传连锁图谱。利用62对AFLP引物组合,对亲本和93个个体进行了分离分析,共得到3572个标记,其中具有多态性的标记为点数为1133个,多态性比例为31.5%。平均每个引物对产生18.3个多态片段。1133个多态性位点中,294个标记在父母本中都出现并在后代中分离,839个标记在父本或母本中出现并在子代分离,其中母本443(52.8%)个分离标记,父本396(47.2%)个分离标记。卡方检验显示,556个标记符合孟德尔1:1分离。筛选微卫星标记中30个在家系中具有作图信息,其中19个可用于母本作图,19个可用于父本作图。 利用Mapmaker 3.0/EXP软件对分离标记进行连锁分析。358个分子标记用于雌性遗传连锁分析,其中包括19个微卫星标记,199个AFLP标记和11个微卫星标记定位在雌性框架图谱中。雌性框架图谱共有25个连锁群,总长度为3148.3 cM。标记之间最大间隔为37.5 cM,平均间隔为17.0 cM,连锁群的分子标记数最大为21个最小为4个。用于雄性连锁分析的分子标记共有332个,其中包含19个微卫星标记。207个标记定位于23个连锁群上,其中AFLP标记数为196个,微卫星标记数为11个。23个连锁群总长度为3059.8 cM,标记间最大间隔38.6 cM,平均间隔16.6 cM。每个连锁群的长度范围在40 cM到271.4 cM之间,标记数在18到4个之间,包括二、三连体在内的雄性连锁图谱共覆盖3227 cM。雌雄基因组的预测长度分别为4053.7 cM和3816.3 cM,因此,所构建的雌雄连锁图谱覆盖率分别为84.0%和84.5%。通过共有微卫星标记,有3个连锁群在两个图谱中对应。分子标记在两个图谱中呈均匀分布,没有成簇现象。 分子标记筛选、遗传图谱的构建为刺参分子标记辅助选择育种,经济性状QTL定位和比较基因作图打下基础,并且最终将促进中国刺参遗传改良和新品种的培育工作。 第二部分 卵母细胞成熟过程研究 对刺参卵母细胞的体外诱导成熟方法进行探索,并且通过透射电子显微镜、扫描电子显微镜和激光共聚焦显微镜结合超薄切片技术及间接免疫荧光染色技术研究卵母细胞成熟的生物学过程。 分别利用在海参中有诱导作用的海星神经提取液和二硫苏糖醇(DTT)对从成熟卵巢解剖出的刺参卵母细胞进行诱导成熟试验,结果显示,刺参的卵母细胞在海水中不会发生自发成熟,海星神经提取液以及神经提取液加滤泡悬浮液对卵母细胞没有诱导成熟的作用,而二硫苏糖醇处理可以诱导卵母细胞生发泡破裂,当DTT溶液的浓度处于10-1 mol/L到10-3 mol/L之间时,对刺参卵母细胞的促熟作用较为明显,在10-2 mol/L左右时,卵母细胞的诱导成熟率可以达到90%以上。未成熟的卵母细胞处于第一次减数分裂前期,不具备受精能力。经DTT诱导后,生发泡发生移动并破裂,染色体排列到赤道板上,然后第一、二极体先后排出,诱导成熟的卵母细胞排出极体的时间与自然受精的卵子一致。在卵母细胞成熟过程中有受精膜举起的现象,说明精子入卵不是受精膜举起的必要条件。卵母细胞只有在生发泡破裂之后才具有受精能力,从生发泡破裂到第二极体排出前的整个减数分裂过程中,卵母细胞都可以受精,但是只有在第一极体排出前受精的卵母细胞才能发生卵裂。人工促熟的卵母细胞受精后,形成的胚胎似乎并不能正常发育,试验过程中最多只得到了8细胞期的胚胎,之后细胞便产生畸形并停止分裂,最终裂解消失。 利用DTT诱导刺参卵母细胞成熟,综合运用光镜、电子显微镜及激光共聚焦技术观察卵母细胞成熟过程,分析了卵母细胞表面动物极突起在卵母细胞脱滤泡中的作用,以及卵母细胞动物极突起和微管组织在生发泡移动过程中所起的作用。卵母细胞通过动物极突起连接到滤泡上,在脱滤泡作用开始时,卵母细胞动物极突起刺入并穿过滤泡膜,使得滤泡膜表面形成一个缺口,然后整个卵母细胞开始从缺口处挤出。脱滤泡的作用力来源有两种:胶膜层的水合作用以及滤泡的收缩。通过激光共聚焦显微镜观察,未成熟的卵母细胞中存在5种类型的微管,并且有两个微管组织中心锚定在卵母细胞突起下方。减数分裂重新启动时,生发泡沿微管向动物极移动,至细胞膜下时破裂。微管解聚对照实验证明驱动生发泡移动的细胞结构为微管束。生发泡破裂后,两个微管组织中心组织形成减数分裂纺锤体,然后第一极体以“收缩-排出”的独特方式排出。 本研究填补了刺参繁殖生物学研究中的缺失环节,为刺参人工繁育技术提供理论基础和指导。
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The effects of acute temperature challenge on some immune parameters of haemocyte in Zhikong scallop, Chlamys farreri, recognised as a temperature sensitive bivalve species, were evaluated over a short period of time. Scallops were suddenly transferred from 17 degrees C to 11 degrees C, 23 degrees C and 28 degrees C for a period of 72 h. Total haemocyte count (THC), percentage of phagocytic haemocytes, reactive oxygen species (ROS) production, acid phosphatase (ACP) and superoxide dismutase (SOD) activities (in both haemocyte lysate and cell-free haemolymph) were chosen as biomarkers of temperature stress. Results demonstrated that the percentage of phagocytic haemocytes and ACP activity in cell-free haemolymph of scallops challenged at 28 degrees C for 72 h significantly decreased. By contrast, reactive oxygen species production by haemocytes increased when compared to the initial values. It is concluded that haemocyte activities of C. farreri appear to be compromised when scallops were transferred from 17 degrees C to 28 degrees C. Meanwhile, no obvious negative effect of acute temperature stress was detected on haemocyte activities of C. farreri challenged at 11 degrees C, which highlighted the high tolerance of scallops to acute decrease of seawater temperatures. (C) 2007 Elsevier B.V. All rights reserved.
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贵阳市位于贵州省中部云贵高原东斜坡地带,地处东经106°07′至107°17′,北纬262°11′,至272°22′之间,属东部平原向西部高原的过渡地带,地形地貌多样,海拔高,纬度低,具有亚热带湿润温和型气候的特点,资源丰富,能源充足,自然环境得天独厚。本论文详细研究了贵阳市8046平方公里面积内表层土壤中砷、福、铬、铜、汞、镍、铅、锌8种重金属污染元素的环境地球化学特征,确定了土壤环境地球化学基线,并建立了判别自然的和人为的环境影响的地球化学指标,进而计算污染参数:重金属累计指数和污染程度,在此基础上进行了土壤重金属污染来源分析。取得认识如下:1、贵阳市表层土壤中重金属污染元素的均值、标准差、极值、主要含量区间分别是:砷18·ogmg/kg、11·57 mg/kg、79.30mg/kg、AS95.9%<40mg/kg;福0.302mg/kg、0.363mg/kg、2.620mg/lcg、Cd95.7%<1.000mg/kg;铬75.3mg/kg、37.3mg/kg、271.0mg/kg、Cr95.9%<150.0mg/1cg;铜43.lmg/kg、30.3mg/kg、213.0mg瓜g,Cu94.6o/<100mg/kg;铅43.2mg/kg、31.3mg/kg、318.9mg/kg,Pb95.5%<100.0mg/kg;汞0.222mg/kg、0.531mg/kg、7.030mg/kg,Hg98.2%<1.00Omg/kg;镍38.3mg/kg、14.9mg/kg、102.5mh/kg,Ni95.8%<70mg/kg;锌84.7mkg、49.8mg/kg、385.0mg/kg,Zn93.4%<150.0mg/kg。2、利用相对累计总量分析方法和相对累计频率分析方法确定贵阳市表层土壤中重金属元素的基线值和受人为影响的下限:砷为9.04mk和29.0mg/kg;福为0.068mg/kg和1 .OIOms/kg;铬为44.0mg/kg和100.2mg/kg;铜为18.8mg/kg和68.4mg/kg;铅为14.8mg/kg和70.lmg/kg;汞为0.045mg/kg和0.530mkg;镍为17.0mg/kg和57.0mg/kg;锌46.3mg/kg和112.0mg/kg。3、对贵阳市表层土壤重金属含量进行地质累计指数分析,结果显示贵阳市的表层土壤中:41%未受砷污染,43%的在无污染到中度污染之间,14%的中度污染,只有2%的介于中度污染到强污染之间;40%未受福污染,19%无污染到中度污染之间,14%的中度污染,19%的介于中度污染到强污染之间,7%的强污染,1%的表层土壤强污染到极强污染之间;46%未受铬污染,47%在无污染到中度污染之间,6.8%的中度污染,0.2%介于中度污染到强污染之间;38%未受铜污染,38%在无污染到中度污染之间,22%的中度污染,2%的介于中度污染到强污染之间;18%未受铅污染,47%在无污染到中度污染之间,28%的中度污染,3%介于中度污染到强污染之间;12%未受元素汞污染,37%在无污染到中度污染之间,36%的中度污染,11%介于中度污染到强污染之间,2%的强污染,1%的介于强污染与极强污染之间,1%的极强污染;19.2%未受镍污染,63.7%在无污染到中度污染之间,16.8%的中度污染,0.3%介于中度污染到强污染之间;41%未受锌污染,50%在无污染到中度污染之间,7%的中度污染,2%介于中度污染到强污染之间。4、贵阳市表层土壤中重金属元素含量的污染程度计算显示:砷的污染程度最大为4,27,50.2%的表层土壤未受污染,97%的表层土壤污染程度小于2,总污染程度略大于O,即受到轻微污染;蝠的污染程度最大为12.1,57.9%的表层土壤未受污染,%%的表层土壤污染程度小于4,总污染程度大于。,即受到污染;铬的污染程度最大为2.01,69%的表层土壤未受到重金属元素铬的污染,30.6%的表层土壤受到轻微污染,总污染程度小于O,即未受到污染;铜的污染程度最大为5.09,53.2%的表层土壤未受到重金属元素铜的污染,总污染程度略大于0,即受到轻微污染;铅的污染程度最大为8.11,49.9%的表层土壤未受到重金属元素铅的污染,总污染程度略大于0,即受到轻微污染;汞的污染程度最大为45.87,56.1%的表层土壤未受到重金属元 素汞的污染。总污染程度大于0,即受到污染;镍的污染程度最大为1.56,64%的表层土壤未受到重金属元素镍的污染,总污染程度小于O,即未受到污染;锌的污染程度最大为2.85,77.8%的表层土壤未受到重金属元素锌的污染,总污染程度小于0,即未受到污染。综合考虑8种重金属污染元素,贵阳市40.2%的表层土壤无重金属元素污染,巧%的表层土壤在无污染到轻微污染之间,36.1的表层土壤轻微污染,7.2%的中度污染,1.4%的表层土壤严重污染。5、福和镍只存在较少的污染区域,其余六种元素都存在局部的重金属含量受人为因素影响。砷的污染区域主要集中在筑东部的马场和西部清镇的暗流、王家院等地;铬的污染区域主要集中筑南部的花溪马林、西部的暗流一酒坪等地;铜的污染区域则主要集中在筑南部的燕楼马林处;汞的污染区域分布在筑北开阳双流、筑西北六广以及筑中扎佐三片;铅的污染区域分布在筑东北的宅吉、城关;筑西麦格等处;而锌的污染区则集中在筑东北面的开阳花梨和城关。总体来说,镍、铜的含量是处于最安全的位置,而汞、铅的警戒区域面积很大,几乎函盖了全部研究区域,福次之,砷、锌、铬适中。6、贵阳市表层土壤中重金属污染元素的含量主要与矿山、长期的农业措施和燃煤带来的污染有关。所有重金属含量超标区几乎都对应于矿区,其污染可能来自于母岩,也可能来自矿区生产而导致的“三废”污染。汞、铅、镉的“警戒”区域面积较大,主要是由长期的农业污染造成,特别是磷肥和含污染元素的农药、除草剂等的施用,汞、隔“警戒”区域面积较大的原因还与燃煤后重金属的大气沉降有关。另外砷的污染也和燃煤后大气沉降有关。贵阳市表层土壤没有受到重金属污染元镍的污染。7、在本研究区域内,重金属含量呈现不同含量等级的土类是由于长时间受人为影响的结果,而重金属含量处于单一等级区间的土类则受人为因素影响较小,其含量区间反映了背景值含量范围。在贵阳市的表层土壤中,黄壤、石灰土、水稻土受人为影响较多,石质土、粗骨土、紫色土、黄棕壤受人为影响适中,沼泽土和山地草甸土受人为影响较少。8、本文建议:(1)在乌当区金华镇三铺村、修文县久长镇新隆村、白云区牛场乡小山村、修文县扎佐镇丁官村、修文县大石乡天桥村、开阳县双流镇凉水井村、修文县六广镇滨江村这几个综合污染较为严重的区域采取政府宏观调控手段,指导当地农户进行绿化苗木、花卉等不进入食物链的植物,或者在合适的地方,进行退耕还林,种植生态林。同时建议有关部门在这些区域开展土壤重金属治理工作;(2)在清镇市的暗流一卫城、王家院、水塘以及开阳县马场一哨上等砷含量较高区域种植旱生禾谷类食用籽粒的作物,如小麦、玉米、高粱等,不能种植水生作物和叶菜类作物;在北部开阳双流片、西北部修文六广一大石片、筑中扎佐一牛场片汞含量较高区域推广竺麻的种植;在东北部开阳花梨一城关锌含量较高区域建议农户种植玉米;在开阳的宅吉一龙水、城关和清镇的麦格片区铅含量较高区域,大力发展烟草的种植;在修文久长、大石、开阳城关一马场、清镇麦格、乌当水田一新堡等搞含量较高地区推荐种植豆科食用籽粒作物。9、综合考虑国家《土壤环境质量标准(GB15618一1995)》中规定监测的8种重金属污染元素,污染程度(Cd)的判别指标可以定量化为:Cd≤O:无污染;O<Cd燕1无污染到轻微污染;1<Cd≤5:轻微污染:5<Cd≤10中度污染;Cd>10:严重污染。
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2010
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2010
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2010
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Inexpensive and permanently modified poly(methyl methacrylate)(PMMA) microchips were fabricated by an injection-molding process. A novel sealing method for plastic microchips at room temperature was introduced. Run-to-run and chip-to-chip reproducibility was good, with relative standard deviation values between 1-3% for the run-to-run and less than 2.1% for the chip-to-chip comparisons. Acrylonitrile-butadiene-styrene (ABS) was used as an additive in PMMA substrates. The proportions of PMMA and ABS were optimized. ABS may be considered as a modifier, which obviously improved some characteristics of the microchip, such as the hydrophilicity and the electro-osmotic flow (EOF). The detection limit of Rhodamine 6G dye for the modified microchip on the home-made microchip analyzer showed a dramatic 100-fold improvement over that for the unmodified PMMA chip. A detection limit of the order of 10(-20) mole has been achieved for each injected phiX-174/HaeIII DNA fragment with the baseline separation between 271 and 281 bp, and fast separation of 11 DNA restriction fragments within 180 seconds. Analysis of a PCR product from the tobacco ACT gene was performed on the modified microchip as an application example.
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http://www.archive.org/details/islamandmissions012033mbp
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© 2014 The Authors.Caenorhabditis elegans larvae reversibly arrest development in the first larval stage in response to starvation (L1 arrest or L1 diapause). Insulin-like signaling is a critical regulator of L1 arrest. However, the C. elegans genome encodes 40 insulin-like peptides, and it is unknown which peptides participate in nutritional control of L1 development. Work in other contexts has revealed that insulin-like genes can promote development ("agonists") or developmental arrest ("antagonists"), suggesting that such agonists promote L1 development in response to feeding. We measured mRNA expression dynamics with high temporal resolution for all 40 insulin-like genes during entry into and recovery from L1 arrest. Nutrient availability influences expression of the majority of insulin-like genes, with variable dynamics suggesting complex regulation. We identified thirteen candidate agonists and eight candidate antagonists based on expression in response to nutrient availability. We selected ten candidate agonists (. daf-28, ins-3, ins-4, ins-5, ins-6, ins-7, ins-9, ins-26, ins-33 and ins-35) for further characterization in L1 stage larvae. We used destabilized reporter genes to determine spatial expression patterns. Expression of candidate agonists is largely overlapping in L1 stage larvae, suggesting a role of the intestine, chemosensory neurons ASI and ASJ, and the interneuron PVT in control of L1 development. Transcriptional regulation of candidate agonists is most significant in the intestine, as if internal nutrient status is a more important influence on transcription than sensory perception. Phenotypic analysis of single and compound deletion mutants did not reveal effects on L1 developmental dynamics, though simultaneous disruption of ins-4 and daf-28 increases survival of L1 arrest. Furthermore, overexpression of ins-4, ins-6 or daf-28 alone decreases survival and promotes cell division during starvation. These results suggest extensive functional overlap among insulin-like genes in nutritional control of L1 development while highlighting the role of ins-4, daf-28 and to a lesser extent ins-6.
Resumo:
The objective of this cross-sectional study was a comprehensive nutrition and health assessment to provide a basis for future intervention strategies for an elderly population attending a day-care centre. Socio-demographic, health and 24-hour recall dietary intake questionnaires were administered and anthropometric and biochemical measurements taken. The results indicate that the majority of respondents had an income of between R501 and R1 000 (South African rand) per month and most of them reported an occasional lack of funds to meet basic household needs, confirming the presence of food insecurity. Daily dietary intakes (mean [+ or -] Standard Deviation [SD]) of the women were 5 395 [+ or -] 2 946 kJ energy, 47 [+ or -] 27 g protein, 28 [+ or -] 21 g fat and 196 [+ or -] 123 g carbohydrates compared to 8 641 [+ or -] 3 799 kJ, 86 [+ or -] 48 g, 49 [+ or -] 32 g and 301 [+ or -] 139 g of the men, respectively. The majority (83.6%) of the women were overweight (body mass index [BMI] [greater than or equal to] 25) or obese (BMI [greater than or equal to] 30) whilst 78% had a mid-upper arm circumference (MUAC) of [greater than or equal to] 21.7 cm. Mean intakes of micronutrients were low in comparison to reference standards and serum zinc levels were suboptimal. Obesity, hypertension and raised total serum cholesterol levels indicated an increased risk for coronary heart disease. It can be concluded that a low income, household food insecurity and risk factors associated with malnutrition and non-communicable diseases were prevalent in this elderly population. OPSOMMING Die doelwit van hierdie dwarssnitstudie was ‘n omvattende bepaling van voeding- en gesondheidstatus om as basis te dien vir toekomstige intervensiestrategieë vir ’n groep bejaardes wat ’n dagsentrum besoek. Sosiodemografiese, gesondheid- en 24-uur herroep-dieetinname vraelyste is voltooi en antropometriese en biochemiese metings is geneem. Die resultate het bevestig dat die meerderheid respondente ‘n maandelikse inkomste van tussen R501 en R1 000 (Suid-Afrikaanse rand) gehad het. Die meeste het ‘n geldtekort vir basiese huishoudelike behoeftes gerapporteer wat dui op huishoudelike voedselinsekuriteit. Daaglikse dieetinnames (gemiddeld±standaardafwyking [SA]) van die vroue was onderskeidelik 5 395±2 946 kJ energie, 47±27 g proteïen, 28±21 g vet en 196±123 g koolhidrate in vergelyking met 8 641±3 799 kJ, 86±48 g, 49±32 g en 301±139 g vir die mans. Die meerderheid (83.6%) van die vroue was oorgewig (liggaamsmassa-indeks [LMI] >25) of vetsugtig (LMI > 30) en 78% het ’n middel-bo-armomtrek (MUAC) van > 21.7 cm gehad. Gemiddelde mikronutriëntinnames was laag in vergelyking met die verwysingstandaarde en serumsink was suboptimaal. Vetsug, hipertensie en verhoogde totale serumcholesterolvlakke het op ‘n verhoogde risiko van kardiovaskulêre siekte gedui. Die resultate het dus bewys dat lae inkomste, huishoudelike voedselinsekuriteit en die risikofaktore wat met wanvoeding en leefstylsiektes geassosieer word, teenwoordig was.