Carbon nanotube quantum resistors   总被引：1，自引：0，他引：1  

S Frank  P Poncharal  ZL Wang  WA Heer 《Science (New York, N.Y.)》1998,280(5370):1744-1746

The conductance of multiwalled carbon nanotubes (MWNTs) was found to be quantized. The experimental method involved measuring the conductance of nanotubes by replacing the tip of a scanning probe microscope with a nanotube fiber, which could be lowered into a liquid metal to establish a gentle electrical contact with a nanotube at the tip of the fiber. The conductance of arc-produced MWNTs is one unit of the conductance quantum G0 = 2e2/h = (12.9 kilohms)-1. The nanotubes conduct current ballistically and do not dissipate heat. The nanotubes, which are typically 15 nanometers wide and 4 micrometers long, are several orders of magnitude greater in size and stability than other typical room-temperature quantum conductors. Extremely high stable current densities, J > 10(7) amperes per square centimeter, have been attained.  相似文献   

抗逆高羊茅新品种黔草1号的特征特性   总被引：1，自引：2，他引：1  

吴佳海  牟琼  罗天琼  唐成斌  尚以顺  莫本田  瓦庆荣 《种子》2007,26(12):101-104

介绍了抗逆高羊茅新品种黔草1号(Festuca arundinacea Schreb.cv.Qiancao No.1)的育种过程及其优良特性。在贵州省及四川、广西、新疆等地种植的种子平均产量比对照品种凌志和原始群体高出20%以上。返青期比引进品种凌志提前7天,枯黄期晚3天;是目前我国育成的自主知识产权优良抗逆草坪型新品种,是运动场草坪、环境绿化、生态治理和改良天然草场的理想草种之一。适宜我国长江中下游低山、丘陵等地区种植。  相似文献   

Metaphyseal osteomyelitis in an immature Abyssinian cat     

WA BRADLEY 《Australian veterinary journal》2003,81(10):608-608

Metaphyseal osteomyelitis is a rarely described condition in small animals, especially the cat. Infection, most commonly Staphylococcus sp, is considered to occur in the metaphyseal region of the immature animal due to vascular anomalies that predispose to the haematogenous seeding of bacteria in this area. There is also speculation that the characteristics of the bacteria that allow them to adhere to cartilage matrix, rather than vascular linings and erythrocytes, may provide an advantage for colonisation in the metaphysis, resulting in infection. This case describes the successful management of a case of distal radial metaphyseal osteomyelitis in an immature cat using surgical intervention and antibacterial therapy.  相似文献   

鸡新城疫病毒HN基因亚单位疫苗诱导免疫保护的实验研究   总被引：3，自引：0，他引：3  

丁壮  金宁一  王兴龙  米志强  夏志平  王承宇 《动物医学进展》2002,23(1):49-51

实验分别将应用Bac to Bac系统表达的新城疫病毒四平株和长春株血凝素-神经氨酸酶基因（HN基因）蛋白的重组杆状病毒感染Sf-9昆虫细胞后28℃培养72h后，洗涤、收集昆虫细胞，离心浓缩，-20℃冻融3次，用HA-HI实验和HN单抗中和试验测定表达产物的活性，将表达的重组蛋白作为亚单位疫苗免疫鸡，用间接ELISA和HI试验测定鸡体内抗体效价，免疫后第15d用国家标准强毒NDVF48E8攻毒，统计免疫保护率，结果表明，表达的NDVHN重组蛋白能够诱导鸡体产生抗NDV特异性IgG抗体和HI抗体，实验Ⅰ组（四平株）雏鸡保护率为65%，实验Ⅱ组（长春株）雏鸡保护率为100%。  相似文献   

不同乳酸菌发酵乳对高血脂症大鼠肠道菌群的影响     

印伯星  李艳  瞿恒贤  瓦云超  王春雷  席文博  顾瑞霞 《中国畜牧杂志》2019,(6):100-106

试验旨在探究不同乳酸菌发酵乳对高血脂模型大鼠血脂与肠道菌群的调节作用。将体重为(120±10)g的 40 只 SD 雄性大鼠随机分为空白对照组(C 组)、高脂模型组(M 组)、L. rhamnosus LV108 发酵乳组(LV组)及混合乳酸菌(LV108 发酵乳∶grx08 发酵乳∶grx12 发酵乳=2∶1∶1)发酵乳组(H 组),每组 10 只,建模后干预(1 mL/100 g,1×108 CFU/mL)4 周,测定大鼠血脂及大鼠粪样细菌 16S rDNA 的 V3-V4 区,并对大鼠肠道微生物和血清血脂水平的相关性进行分析。结果表明:LV 组和 H 组大鼠血清中甘油三酯、总胆固醇及低密度脂蛋白胆固醇含量显著降低,体重增长被抑制;LV 组和 H 组中大鼠肠道菌群的丰度及多样性显著提高,且 H 组大鼠肠道菌群的丰度高于 LV 组(P<0.05);LV 组和 H 组大鼠粪便中 Lactobacillus spp.、S24-7 spp 和 Treponema spp.等菌属显著升高,Peptostreptococcus spp.、Clostridium spp.、Turicibacter spp、Escherichia spp.及 Desulfovibrio spp.等菌属显著降低。结果提示,L. rhamnosus LV108发酵乳及混合乳酸菌发酵乳均能改善大鼠血脂水平并恢复大鼠肠道菌群的多样性及菌群构成。  相似文献   

Rigid removable cover for dorsal wound protection and tube fixation in pigs          下载免费PDF全文

GD Stynes  GK Kiroff  WA Morrison  GA Edwards  RS Page  MA Kirkland 《Australian veterinary journal》2016,94(4):111-116

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Systemic Concentrations of Endogenous and Exogenous FSH in Anoestrous Ewes Superstimulated with Folltropin^®-V     

PM Bartlewski  KJ Fuerst  BD Alexander  WA King 《Reproduction in domestic animals》2009,44(2):353-358

The synchronization of follicular waves with medroxyprogesterone acetate (MAP) and oestradiol‐17β (E₂‐17β) prior to ovarian superstimilation in anoestrous ewes reduces the variability in superovulatory responses by an unknown mechanism. Follicle stimulating hormone (FSH) is a primary promoter of antral follicular development, but the relevance of circulating FSH concentrations to the superovulation performance in ewes has not been examined. Eighteen anoestrous Rideau Arcott ewes (May–June) were superovulated with Folltropin^®‐V (porcine FSH), with (n = 8; treated ewes) or without (n = 10; control ewes) a single i.m. dose of 350 μg of E₂‐17β, given on the sixth day of a 14‐day treatment with MAP‐releasing intravaginal sponges (60 mg). The superovulatory treatment, begun 6 days after E₂‐17β injection, consisted of six i.m. applications of Folltropin^®‐V given twice daily (at 08:00 and 16:00 h), followed by an i.m. injection of GnRH (50 μg). Blood samples collected every 8 h throughout the 3‐day treatment, were analysed by radioimmunoassays for concentrations of ovine and porcine FSH, using species‐specific standards and primary antibodies. Serum concentrations of oFSH were greater (p < 0.05) in the controls compared to treated ewes at 40, 64 and 72 h and the variability in mean oFSH concentrations was greater (p < 0.05) in control ewes at 40, 48, 64 and 72 h after the 1^st Folltropin^®‐V injection. There were no differences (p > 0.05) between the two groups in serum concentrations of pFSH. Significant correlations were recorded between the number of corpora lutea (CL) and oFSH concentrations at 8 h (r = 0.72, p < 0.05), 16 h (r=0.63, p < 0.05) and 64 h (r = 0.84, p < 0.01) after the 1^st Folltropin^®‐V injection. The total number of recovered embryos was positively correlated to oFSH concentrations at 56 h (r = 0.69, p < 0.05). We concluded that changes in endogenous FSH concentrations during ovarian superstimulation with pFSH might contribute to the variability in superovulatory responses in ewes.  相似文献   

Two new species of protogyrodactylus (Monogenoidea: Dactylogyridae) from the gills of Gerres nigri (Teleostei: Gerreidae) from Senegal     

Boeger WA  Diamanka A  Pariselle A  Patella L 《Folia parasitologica》2012,59(1):59-63

Protogyrodactylus ethiopicus sp. n. and P. kritskyi sp. n. are described from the gills of Gerres nigri Günther (Gerreidae, Perciformes) captured from the estuary of the Sine-Saloum River (Senegal, West Africa). These new species differ from previously described species within the genus by a mid- or dextro-ventral vaginal opening (dextral in all other species). They are part of a morphological species group within Protogyrodactylus Johnston et Tiegs, 1922 that has the tip of the superficial root of the ventral anchor resembling a hook and two anterior projections on the anterior margin of the ventral bar. Protogyrodactylus ethiopicus differs from the remaining species in this group mainly by the morphology of the base of the male copulatory organ (MCO), which is disk-shaped, and the shape of the anterior projections of the ventral bar (round in the new species and relatively elongate in the other species of the group). The other new species, P. kritskyi, differs from all others in the same morphological group in having a MCO with a greatly expanded base that bears a heel-like subterminal sclerotization.  相似文献   

Dukes'' Physiology of Domestic Animals     

WA Snowdon 《Australian veterinary journal》1994,71(6):187-187

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Different Culture Media Requirements of IVF and Nuclear Transfer Bovine Embryos   总被引：3，自引：0，他引：3  

GF Mastromonaco  E Semple  C Robert  GJ Rho  DH Betts  WA King 《Reproduction in domestic animals》2004,39(6):462-467

Important differences exist between in vitro fertilized (IVF) and nuclear transfer (NT) bovine embryos. Studies have shown that although in vitro development is comparable, post-implantation survival is greatly reduced in NT embryos. In this study, we compare serum and bovine serum albumin (BSA) supplementation during oocyte maturation and embryo culture of IVF and NT embryos. In experiment 1, oocytes and embryos were randomly distributed into different treatment groups consisting of synthetic oviductal fluid (SOF) medium supplemented with either serum, fatty acid-free BSA (FAF) or fraction V BSA during maturation and/or culture to assess IVF embryo development. In experiment 2, oocytes were matured in SOF + serum or SOF + FAF and reconstructed embryos were cultured in SOF + FAF to assess NT embryo development. Among the IVF treatment groups, a greater number of blastocysts were observed in the steer serum (SER) group (IVM and IVC in SOF + serum) on day 6; however, no significant differences were seen in blastocyst development from day 8 onwards. Hatching frequencies on days 8 and 9 were significantly greater in groups with serum, with the exception of FAF (IVM and IVC in SOF + FAF) on day 9. For the NT treatment groups, the presence of serum during IVM resulted in a higher proportion of MII oocytes and increased blastocyst development and hatching rates were compared with supplementation of FAF. These results indicate that both serum and FAF provide comparable embryo development for IVF but not for NT bovine embryos.  相似文献