Asteroid 1986 DA: Radar Evidence for a Metallic Composition

Echoes from the near-Earth object 1986 DA show it to be significantly more reflective than other radar-detected asteroids. This result supports the hypothesis that 1986 DA is a piece of NiFe metal derived from the interior of a much larger object that melted, differentiated, cooled, and subsequently was disrupted in a catastrophic collision. This 2-kilometer asteroid, which appears smooth at centimeter to meter scales but extremely irregular at 10- to 100-meter scales, might be (or have been a part of the parent body of some iron meteorites.     

Bohr Effect: Absence in a Molluscan Hemocyanin

The hemocyanin of the keyhole limpet, Diodora aspera, shows no Bohr effect within the pH range 6.88 to 7.84. At 10 degrees C the pressure of half-saturation is 5 mm-Hg of oxygen pressure. A moderately positive interaction occurs among the oxygen-combining sites during oxygenation. The heat of oxygenation is calculated to be approximately -12.6 kcal/mole of oxygen. The pH of normal blood of Diodora is lower than that of many other marine molluscs.     

SEM-EDX对几种纤维的形态结构和元素成分比较研究

对几种指定纤维进行了扫描电镜 (SEM)观察 ,并且利用X射线能谱仪 (EDX)分别对兽毛的鳞片层、髓质层和化学纤维进行了元素分析 ,建立了不同纤维的比较研究方法 ,具有定性准确、分辨率高、特征信息明显之特点 ,已用于商检和物证鉴定中。     

Estradiol: Evidence for its Direct Effect on Hypothalamic Neurons

When estrogen has been implanted in the arcuate nucleus of the hypothalamus of the rat, the size of the nucleoli of the neurons in this nucleus decreases, as determined by measurement of the mean diameters. These changes are accompanied by atrophy, similar to that caused by hypophysectomy, of the ovaries and uterus of the female or testes and accessory glands of the male.     

人工饲养白鹳、黑鹳卵壳成分分析及超微结构观察

通过对白鹳和黑鹳的卵壳成分测定及电镜扫描发现:白鹳卵壳中N、Fe、P、Hg的含量明显高于黑鹳,而黑鹳中的Na则高于白鹳;白鹳和黑鹳的卵壳中均检出超量重金属污染物铅(Pb)、镉(Cd)、锶(Sr)、砷(As)、汞(Hg),说明母体也受到了一定程度的污染;白鹳和黑鹳的卵壳均分为外表结晶层、栅栏层、乳突层和壳膜层,两卵壳厚度的差异主要体现壳膜厚度上;白鹳卵壳外表面的单位气孔密度明显低于黑鹳,其气孔口形状规则,孔壁较平滑,而黑鹳则不规则且粗糙;白鹳壳膜纤维密度小,排列不规则,而黑鹳壳膜则密度稍大,排列呈竹林状。白鹳和黑鹳卵壳在研究结果上的异同,体现了这两个亲缘种在生理、遗传、系统发育上种间相似性和特异性。     

木薯酒中的主要化学成份及其对酒质的影响

 通过气相色谱-质谱联合仪对木薯酒成份的分析,讨论了木薯酒产生异味的原因,并提出改善木薯酒质量的措施。     

木薯酒中的主要化学成份及其对酒质的影响

通过气相色谱—质谱联合仪对木薯酒成份的分析, 讨论了木薯酒产生异味的原因, 并提出改善木薯酒质量的措施．     

栽培料配方对褐蘑菇产量的影响

褐蘑菇是张家口市著名特产--口蘑系列中的1个种类,主要分布于张家口地区北部坝上高原的天然牧场,属于低温型食用真菌.褐蘑菇又称“香口蘑“,特点是香味浓郁,肉质肥厚、鲜嫩,营养丰富,有很高的保健价值.1997年开始大面积人工栽培,现已发展为坝上的特色支柱产业.本研究将褐蘑菇进行南移栽培,探讨不同栽培原料及其配方对褐蘑菇产量的影响,旨为冀中南部进行褐蘑菇生产提供依据.……     

日粮组成对早期断奶仔猪腹泻的影响

仔猪早期断奶SEW(10～21日龄),不仅可以增加母猪年产胎次,提高母猪生产能力和栏舍利用率,同时可以及早弥补仔猪的营养需要,减少病原从母体进入仔猪的机会,节约公母猪的饲养成本,有利于提高猪场的综合效益。但是早期断奶又会因为仔猪消化能力和抗逆能力差,造成食欲差、消化不良、饲料利用率低、生长缓慢、下痢、精神状况以及外貌表现不佳等所谓“仔猪早期断奶综合征”。其中主要表现为仔猪断奶后腹泻(PWD)、水肿病(OD)和内毒素休克(ES)等,而早期断奶仔猪的腹泻问题更为突出。引起腹泻的原因非常多,主要包括肠道致病性大肠杆菌和其它致病…     

重组真菌免疫调节蛋白对巨噬细胞RAW 264.7激活应答的研究

真菌免疫调节蛋白(fugal immunomodulatory proteins,FIPs)是一类从高等大型真菌中分离的、具有生物活性的小分子蛋白质。在之前的研究中,通过基因改组技术,对来自赤芝(Ganoderma lucidum)和紫芝(G.sinense)的FIP进行了重组改造,获得了具有333bp的FIP突变体FIP-SN15。本研究通过原核表达系统获得了重组FIP-SN15(rFIP-SN15),并利用荧光定量PCR(quantitative real-time PCR,qRT-PCR)技术在转录水平上对rFIP-SN15诱导巨噬细胞TNF-α的功能及其机制进行研究。结果表明,rFIP-SN15在原核表达系统中的产量约为35.31mg/L;rFIP-SN15处理细胞后,TNF-α的转录水平显著上调(P0.05),并且Akt的转录水平上调极其显著(P0.01)。此外,ARG1和mTOR的mRNA水平上调显著(P0.05)。因此,rFIPSN15能够激活小鼠腹腔巨噬细胞RAW 264.7。本研究为进一步验证FIP-SN15的生物学功能提供了有益的参考。     

能感染猪的冠状病毒疾病的诊断与防治

猪血凝性脑脊髓炎病毒、猪流行性腹泻病毒、猪传染性胃肠炎病毒及猪呼吸道冠状病毒都是能感染猪的冠状病毒属。这4种冠状病毒主要通过消化道感染猪机体．都可以引起猪腹泻,为了在临床上有效预防和治疗这4种病毒引起的疾病,该文简单叙述了诊断方法及防治措施,以期为养猪专业户提供理论依据。     

生物活性肽组合物缓解小鼠体力疲劳的作用研究

[目的]研究生物活性肽组合物缓解体力疲劳的作用及机制。[方法]KM小鼠随机分为空白对照组(NC组)、模拟疲劳对照组(FC组)和模拟疲劳生物活性肽组合物处理组(FS组)。FC、FS组小鼠每天进行负重游泳制备疲劳应激模型,连续29 d, NC组不作处理。FS组小鼠每天灌胃相应浓度的生物活性肽组合物,1次/d,连续30 d; NC组和FC组同法灌胃去离子水。末次灌胃30 min后,分别进行负重游泳时间试验、血清尿素氮试验、肝糖原试验、血乳酸试验和红细胞携氧能力试验。[结果]与NC组比较,FC组的血清尿素氮浓度升高(P<0.05);与FC组比较,FS组负重游泳时长增加(P<0.05),血清尿素氮含量降低(P<0.05),血乳酸曲线下面积下降(P<0.01)。[结论]生物活性肽组合物具有一定的增强运动耐力和缓解体力疲劳作用。     

饲料成分对牛乳品质的影响

牛乳具有特殊的营养价值,牛乳中含有蛋白质、脂肪、乳糖、矿物质、维生素、酶等多中营养物质,其中粗蛋白(CP)占3.4%,脂肪占3.4%～3.8%,乳糖占4.7%,牛奶在体内几乎可以100%的吸收,因此,牛奶被人们称之为完全营养物质。但是如果乳牛的饲喂与饲养管理不当很容易使乳产量发生变化。而且,饲料中的一些成分也能影响乳汁的品质,下面就饲料对牛乳成分变化的影响作一综述。1饲料对乳脂的影响乳中的脂肪除由饲料中的脂肪提供外,还有碳水化合物或间接地由蛋白质形成,但最主要受饲料中的精饲料和粗饲料比例的影响。日粮中的精饲料比例大,则牛瘤胃倾向于…     

Neighbor Recognition in Two "Solitary" Carnivores: The Raccoon (Procyon lotor) and the Red Fox (Vulpes fulva)

Male raccoons and red foxes were trapped alive and exposed to each other in captivity. Animals of each species trapped close to one another demonstrated a higher frequency of initial dominance-subordinance relationships and lower frequencies of more intense aggressive interactions than did animals trapped at greater distances from each other. This suggests the existence of neighbor recognition and thus a rudimentary social structure within these free-living "solitary" species.     

不同取浆时间对蜂王浆产量和成分的影响

研究不同取浆时间(48 h和72 h)对蜂王浆产量和成分的影响。以意大利蜜蜂为实验材料,利用免移虫蜂王浆生产技术生产蜂王浆,测定48 h和72 h取浆时单个王台中的王浆产量和单个幼虫重量以及10-HDA的相对含量、挥发性成分和脂溶性成分等指标。结果表明:72 h取浆时王台中王浆产量和幼虫重量都显著高于48 h,但两者10-HDA含量差异不显著;两者都含有21种相同挥发性成分和15种相同脂溶性成分,但48 h取的王浆含有更多的特有挥发性成分,而72 h取的王浆含有更丰富的特有脂溶性成分。     

电晕处理对肉苁蓉表面性能及甘露醇溶出量的影响

为提高肉苁蓉的利用率,对肉苁蓉粉体表面进行电晕等离子体改性处理,并对粉体中甘露醇在水中溶出量进行测定。采用扫描电子显微镜、激光粒度分析、红外光谱分析等多种测试方法分析电晕改性处理前后粉体样品的表观形貌和表面性能的变化规律,对比改性机理进行讨论。结果表明,电晕处理后,粉体表面粗糙,亲水基团含量增加,材料表面润湿性能得到明显改善,甘露醇在水中溶出量也明显增加。其中,最佳的电晕工艺是为0.5kW电晕功率处理2min,此时改性效果最好,甘露醇在水中浸泡20min的溶出率达到63.9%,较未处理的原始样品提高45.8%。通过对肉苁蓉粉末表面进行电晕改性处理,能够有效改善粉体的表面性能,使材料中有效药物成分最大限度地溶出,从而提高中国宝贵中药资源的利用率。     

酵素营养液对小麦草营养成分的影响

[目的]探究酵素营养液对提高小麦草作为优质动物饲料营养成分和营养价值的作用。[方法]选取1种小麦草种子进行萌发,之后开展为期8~10 d的水培试验,定期喷洒酵素营养液(酵素组),对比不施任何营养液的小麦草(对照组),分别测定其叶绿素含量、含水量以及单位质量干品所含的营养成分,即粗蛋白、粗脂肪、粗纤维、粗灰分、无氮浸出物。[结果]酵素组小麦草的粗蛋白、粗灰分含量显著高于对照组;后者的无氮浸出物显著高于前者,均高于60%。[结论]叶面喷洒酵素营养液能显著提高小麦草的营养成分,有效提高其作为动物饲料的综合品质。     

The Effect of Crop Rotation on Soil Nematode Community Composition in a Greenhouse

[Objective] The aim was to identify changes in a nematode community in response to crop rotation and to determine the appropriate catch crop for a greenhouse. [Method] The experiment was carried out in a typical 6-year-old greenhouse,in which cucumber crops were cultivated twice each year(in spring and autumn),and catch crops were planted in summer. The total number of nematodes was counted and nematode community indices were calculated after collecting soil samples in different stages. [Result] Total nematode abundance was decreased in the soils of catch crop in contrast with former crops(cucumber crops). The abundance of the nematode community was reduced in the treatment of crop rotation compared to the soils of catch crop. In addition, the number of nematode taxa was significantly reduced by the treatment of crown daisy compared to the treatments of following crops. Crop rotation regulated the functional composition of the nematode community by increasing the omnivores-predators functional group and decreasing the relative abundance of root herbivores. [Conclusion] These results indicate that crop rotation affects the nematode community in abundance, diversity and functional composition of the nematode community and crown daisy can be served as the most appropriate catch crop in the greenhouse.