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991.
The humoral immune responses and host protection of channel catfish, Ictalurus punctatus (Rafinesque), against Ichthyophthirius multifiliis (Ich) were determined after immunization with live theronts and sonicated trophonts. Immunizations with live theronts or sonicated trophonts were carried out by both bath immersion and intraperitoneal (i.p.) injection. Cutaneous and serum immunoglobulin (Ig) levels and anti-Ich antibodies were measured 12 and 21 days post-immunization. The level of Ich infection and survival of catfish were determined after theront challenge. Cutaneous and serum anti-Ich antibodies were significantly higher (P < 0.05) in fish immunized with live theronts by immersion or i.p. injection, or with sonicated trophonts administered by i.p. injection, than in fish immunized with sonicated trophonts by immersion, with bovine serum albumin by i.p. injection, or non-immunized controls. Host protection was noted only in fish immunized with live theronts by immersion or i.p. injection or with sonicated trophonts by i.p. injection. There was a positive correlation between higher levels of anti-Ich antibodies and host survival in the immunized fish. 相似文献
992.
993.
选择辽宁盘锦光合水产有限公司养殖基地为试验场所,于2002年春季4~5月进行试验。选择5个具有代表性的土池作为试验池,同时另选一土池作为对照池。研究相同N/P比值下不同施肥量对室外土池多盐水体的水化学和浮游植物群落、叶绿素a含量和初级生产力的影响,以及浮游动物对浮游植物的下行效应。共检出浮游生物42种。其中,浮游植物33种,浮游动物9种。浮游植物生物量高达288.2 mg.L-1,优势种为蛋白核小球藻(Chlorella pyrenoidesa)。叶绿素a含量为5.89~325.44μg.L-1。各池在第2次施肥后5~6天,叶绿素a含量达到高值,之后开始下降,8~9 d后恢复到原来水平。初级生产力均值为4.40 g(O2).m-2.d-1,呈低-高-低的变化,极值为1.25 g(O2).m-2.d-1和10.92 g(O2).m-2.d-1。以施N 2.0 mg.L-1、P 0.3 mg.L-1的4#池高峰期维持最长,施肥量的不同对浮游植物的生物量、种类数和种类组成影响较大。在北方地区的多盐水池塘,施氮磷混合肥能有效促进小球藻等藻类增长,达到定向培育的目的。 相似文献
994.
大口胭脂鱼 (Ictiobuscyprinellus )又名巨口牛胭鱼 ,俗称美国鲫鱼 ,原产于北美洲。 1 993年我国从美国引进并试养成功。上海市嘉定区于1 997年从浙江省引进该鱼的苗种 ,当年就养成商品鱼。 2 0 0 1年和 2 0 0 2年嘉定区望新水产良种场进行人工繁殖试验获得成功 ,分别获得鱼苗 2 4 0万尾和 92 5万尾。现将其人工繁殖技术介绍如下。一、亲鱼的培育1 .亲鱼的选择亲鱼主要从养成的商品鱼中挑选 ,选择个体大、无伤、无病、体质健壮的成鱼 ,放在专用塘中进行培育。繁殖用的亲鱼再从亲鱼培育池中挑选 ,年龄要求在 3龄以上 ,体… 相似文献
995.
Dongmei Xu Quan Ji Liwen Tan Guangxiu Tian Fengyu Quan Yanzhi Xia 《Fibers and Polymers》2014,15(2):220-225
Cellulose-Na and cellulose-K fibers are obtained by alkalization and etherification of viscose fiber. Flame retardancy and thermal degradation of cellulose-Na and cellulose-K fibers are investigated using limiting oxygen index (LOI), cone calorimetry (CONE), thermal gravimetry (TG), and differential TG (DTG). The LOI values of cellulose-Na and cellulose-K fibers are 33 and 30, compared with about 20 for viscose fiber. In CONE studies, cellulose-Na and cellulose-K fibers show much lower heat release rates, total heat release and effective heats of combustion than viscose fiber does. In addition, TG and DTG studies reveal that the second initial degradation temperature, the temperature of maximum degradation rate and the maximum degradation rate for cellulose-Na and cellulose-K fibers are much lower than those of viscose fiber. Cellulose-Na and cellulose-K fibers generate much more residue or carbonaceous char than viscose fiber does. Scanning electron microscopy studies of combustion residues after LOI testing indicate that cellulose-Na and cellulose-K fibers produce massive, thick residue crusts. 相似文献
996.
997.
中棉所49在西北内陆棉区的稳定性与丰产性分析 总被引:2,自引:0,他引:2
利用AMMI模型及其双标图分析了中棉所49在2002-2003年和2008-2013年共8年西北内陆棉区国家棉花区域试验中的稳定性表现。结果表明:(1)2002年西北内陆国家棉花区试早中熟组各参试品种的稳定性优劣顺序依次为:中棉所49〉98—60〉K31〉中棉所35〉9—2005〉E3—8—12〉新创1号〉SGK9688〉SGK1779。(2)中棉所49在8年区域试验中的稳定性表现为:在5年试验中表现居第一位、1年试验中表现居第二位、2年试验中居第三位,其稳定性综合表现优良。(3)中棉所49的皮棉产量水平在8年区域试验中总体上稳中有升,体现了较好的丰产性能。可见,中棉所49在西北内陆早中熟棉区具有很强的推广应用价值。 相似文献
998.
Using p-methylphenol as a model compound for phenolic hydroxyl groups on silk fibroin, the reaction kinetics of two typical of reactive dyes including vinyl sulfone reactive dyes and monochlorotriazine reactive dyes with phenolic hydroxyl groups were studied by reverse phase ion-pair high-performance liquid chromatography. The results showed that, the reaction rates of monochlorotriazine reactive dyes with phenolic hydroxyl groups were by far faster than those of vinyl sulfone reactive dyes, attributed to the stability of resultants from the former. The optimum reaction conditions for phenolic hydroxyl groups with vinyl sulfone reactive dyes and monochlorotriazine reactive dyes were at 50–70 °C and pH=8–9 for the former, and at 85–95 °C and pH=8–9 for the latter. The methods and results in this paper would help to deeply study the reaction mechanisms of reactive dyes with silk fibroin. 相似文献
999.
A low torque spinning method has been recently developed by integrating the ring spinning process with false twisting techniques. As a result of false twist and true twist, a novel single yarn of low torque and soft handle is generated. Based on the similar spinning principle, this paper proposed a 2-step spinning method, which is composed of twisting-anduntwisting operation and can be considered as a variant of the low torque spinning method. The proposed spinning method separates the false twisting process into twisting and untwisting processes which are combined in one step in the low torque spinning method. In this paper, physical properties of yarns produced by the proposed spinning method were evaluated and compared with the conventional yarns. Influences of various spinning parameters on the properties of 2-step yarns were also examined. Furthermore, a systematic study of the physical properties of the 2-step yarns and resultant fabrics with respect to the conventional and low torque ones was carried out. The experimental results showed that the 2-step yarns exhibit slightly higher tenacity, lower wet snarl and much less hairiness than the conventional yarns, which, however, are inferior to the low torque yarns, particularly the evenness. The fabrics made by the 2-step yarns show the softest handle feeling, best airpermeability and moderate spirality angle with acceptable pilling resistance. 相似文献
1000.
Co-woven-knitted (CWK) fabrics and multi-layered biaxial weft knitted (MBWK) fabrics were prepared using glass filaments as both the warp and weft yarns and high tenacity polyesters as the stitch yarns with the same stitch length. Then the polyethylene resin was injected into the fabrics by vacuum assisted resin transfer molding to produce composites. Specific bending stress-displacement curves in the course and wale directions of the CWK fabric reinforced composites and the MBWK fabric reinforced composites were analyzed and their bending properties were also compared. Results indicate that the initial segments of all the specific bending stress-displacement curves for the CWK and the MBWK fabric reinforced composites are linear; then the specific bending stresses decrease with the displacements in a wave-like manner until sample destruction. The CWK fabric reinforced composites show plastic failure in course and wale directions, while the MBWK fabric reinforced composites show first fragile failure then plastic failure in course direction and show plastic failure in wale direction. Bending properties in the course direction of the CWK and the MBWK fabric reinforced composites are different from those in their wale direction, respectively. The CWK fabric reinforced composites are of smaller anisotropy than the MBWK fabric reinforced composites. By designing the buckling and distribution of the warp and weft yarns, the axial properties difference can be shortened. 相似文献