刀鲚胸鳍条和耳石微化学“指纹”相似性研究

耳石微化学被广泛应用于鱼类洄游生态学研究,但耳石的摘取难免会造成鱼的死亡和损伤,故寻找可以快捷、非致死地替代耳石进行微化学分析的材料很有意义。为此,本研究比较了刀鲚(Coilia nasus)胸鳍条和耳石微化学的相似性特征。耳石的锶钙比值(Sr/Ca)和Sr含量图谱分型结果分别很好地对应了所研究的洄游型、淡水定居型和陆封型的典型个体。胸鳍条微化学结果显示,湖鲚和短颌鲚2类个体呈现出稳定的低Sr/Ca值?(1.38±0.52)~(2.04±0.74)和(1.40±0.32)~(1.81±0.66)?与刀鲚胸鳍条生活史第一阶段的特征相吻合?(2.06±0.64)~(2.26±0.29)?,这些均反映了淡水生境“指纹”的特征。刀鲚胸鳍条Sr含量图谱和耳石相似,自核心至边缘可分为明显的3个阶段,分别对应于面分布图上自核心至边缘的蓝色、绿色、蓝色之间微化学“指纹”的变化。由此可见,刀鲚胸鳍条可以作为耳石的非致死、低损伤的代替材料,用于刀鲚洄游习性、生境履历等研究。同时,由于胸鳍条具有取样和前处理的优势,在其他鱼类资源或标志放流评价研究时,可以考虑以胸鳍条代替耳石来开展研究。     

Numerical Calculation of Fin Efficiencies and Performances of Rectangular Flat Fins with Modified Geometry

Numerical calculation with FEM was carried out for the fin efficiencies of common rectangular flat fin and three flat fins with modified geometry The result shows that the general heat tasfer performance of fin B2 is higher than that of common flat fin, but the fin efficiency is lower. Both the performances of heat transfer and fin efficiences of fin C and fin D are higher than those of common flat fin. The work of this paper is valuable for optimization design of high efficient fin.     

Experimental investigation of electrothermal defrost tubes’ arrangement on heat transfer and flow resistance characteristics of evaporator

The paper presents new arrangement types of electrothermal defrost tubes and manufactures four evaporator samples. Through a wind tunnel refrigeration experimental test-bed, relatively experiments for every sample are carried to study heat transfer and flow resistances characteristics of evaporator. The experiment results show that in experimental face velocity range from 1.5 m/s to 4.3 m/s compared with flat-fin evaporator, the unit area of cooling capacity of DK-8 evaporator increased 28.1% to 36.2%, the fin surface coefficient of heat transfer raises 79.2% to 83.5%, the compressor COP (Coefficient of Performance) improves 38.2% to 46.9%, and the air side flow resistance decreases 5.29% to 18.3% in the same experimental condition and geometric size. The increase amplitude of COP is obviously higher than air side flow resistance. The experimental investigation results prove that it is completely feasible optimized combing defrost design with heat transfer enhancement design.     

稻谷腹部、背部微观结构差异性分析

【目的】从微观角度对糙米腹部、背部的结构差异性进行研究,从宏观角度对糙米的三点弯曲破碎力学性能进行研究,以建立微观结构与宏观力学性能之间的相关关系,为稻谷籽粒裂纹起始于腹部建立理论依据。【方法】对两个品种糙米横截面的腹部、背部在淀粉粒和细胞层次以及糊粉层进行扫描电镜观察,采用三点弯曲法测试糙米的破碎力学性能。【结果】糙米腹部、背部微观结构在淀粉粒、细胞层次以及糊粉层均存在差异,籽粒腹部、背部微观结构的差异对其腹部、背部的结构强度产生影响,使籽粒腹部的结构强度小于背部,与力学测试性能一致,并且腹部、背部微观断裂形式亦存在差异。【结论】稻谷籽粒在解吸和吸湿条件下裂纹起始于腹部与其腹部结构强度小于背部有关。     

背部肌肉注射含IGF2b基因慢病毒载体对鲤鱼生长的影响

【目的】研究IGF2b基因对建鲤生长及体型的影响。【方法】用含有IGF2b基因的慢病毒载体注射建鲤背部肌肉组织,注射量分别为10,20和40μL/尾,阴性对照组不进行任何处理,阳性对照组注射20μL/尾去离子水。在相同饲养条件下饲养满9个月后,分别测量建鲤的各项生长指标。【结果】注射IGF2b基因的建鲤体质量、体长、体高、体厚、尾长均显著大于阴性对照组和阳性对照组,说明IGF2b基因在建鲤背部肌肉组织中过表达对鲤第2阶段生长同样具有促进作用,IGF2b基因在鲤背部肌肉组织中过表达对鲤的体型也有一定的作用。鲤的体长、体高、体厚的3D图也说明,随着IGF2b基因注射,鲤鱼倾向于具有更大的体长、体高、体厚的值。用多元逐步回归法做体质量的回归方程可知,鲤鱼的体质量与体长、体厚、尾长具有线性关系,利用体长、体厚、尾长这3个自变量进行聚类分析,即可准确得到鲤鱼5个注射组间的聚类关系:阴性对照组与阳性对照组共属一类,3个注射组同为一类,其中注射组中10μL注射组和20μL注射组为一类,40μL注射组为一类,IGF2b基因对鲤鱼体型的影响在注射量大于20μL/尾之后产生了转折,出现了负增长。【结论】IGF2b基因对鲤第2阶段生长同样具有促进作用,且对鲤鱼的体型有一定影响。     

A hypothetical,aetiological relationship between the horse's bit,nasopharyngeal asphyxia and negative pressure pulmonary oedema

Tentative explanations for the aetiology of soft palate instability and dorsal displacement at exercise are based on the proposition that it is caused by one or more, as yet unidentified, neuromuscular or inflammatory diseases. As judged by reviews, none of the treatments based on these assumptions are entirely satisfactory. Most researchers agree that their cause is unknown. In 1999, Cook proposed that they were caused by the bit breaking what should be an airtight lip seal. The present article describes a development of this hypothesis – loss of oral compartment subatmospheric pressure. The feral horse is an obligate nose‐breather and runs with a closed mouth and no air in the oral cavity and oropharynx. Evacuation of air from these compartments is proposed as the primary mechanism, strengthened by the cohesive force of surface tension, whereby the soft palate resists the elevating force of negative pressure on inspiration. It is suggested that subatmospheric pressure in the oral compartment is generated by a single swallow before running. Poll extension supplements the rigidity of the nasopharyngeal tube and reinforces the ostium intrapharyngium seal. In the domesticated horse, the lip seal is broken by a bit and bit‐induced poll flexion, jaw and tongue movement often breaks the ostium seal. Oral atmospheric pressure is proposed as the mechanism for nasopharyngeal asphyxia. It is considered that negative pressure pulmonary oedema – currently known as exercise‐induced pulmonary haemorrhage and conventionally thought to be a separate problem – is one of its clinical signs. It is suggested that the bit is the most common cause of nasopharyngeal asphyxia and that this, in turn, results in a cascade of dynamic obstructions in the larynx and cervical trachea, leading ultimately to pulmonary oedema and ‘bleeding.’ It is concluded that these are sequelae to rules in many disciplines that mandate bit usage.     

7种观赏性剑尾鱼品种间杂交子代的体色及鳍形研究

7种观赏性剑尾鱼的自交、杂交,对其子代的体色(包括眼睛色彩)及鳍形等性状进行统计分析。试验结果表明,黑眼为显性基因控制,红眼为隐性基因控制,体色与眼睛颜色有一定的连锁关系;推测剑尾鱼体色遗传由数量性状基因参与控制;尾鳍燕尾相对于正常尾为显性,而且雄性尾鳍的燕尾和长臀鳍具有连锁性;高背鳍由显性基因控制,正常背鳍由隐性基因控制,拥有正常背鳍的个体,其基因型是隐性纯合,拥有高背鳍的个体,其基因型为杂合,初步推断显性纯合为致死基因型。     

Successful Management of Severe Open Metacarpophalangeal Joint Dorsal Luxation in a Horse

A 3-year-old Darreh-Shuri stallion was presented with left forelimb open dorsal fetlock luxation immediately after being hit by a motorized vehicle. The horse was in a non–weight-bearing position on the affected limb. General physical examination revealed normal vital parameters and no special concurrent abnormality. Radiographic examination in lateromedial and dorsopalmar views of the affected limb showed complete luxation of the metacarpophalangeal joint with no fractures. Ultrasonographic evaluation revealed intact collateral ligaments. Under general anesthesia and following routine preparations, forceful manual pressure was exerted on the distal part of the metacarpus and proximal part of the first phalanx to reduce the luxation. Joint capsule and skin laceration were sutured. Intraarticular amikacin (500 mg) was administered and repeated on the third and fifth days postoperatively. A palmar polyvinyl chloride, synthetic plastic polymer (PVC) splint was placed following adequate padding from the carpus to the toe. The higher and lower third of the splint was casted and the middle part left open to manage the joint and skin lesion. Intraarticular sodium hyaluronate (20 mg) was administered 10 days later. After cast removal following 5 weeks, the stallion revealed no sign of lameness. The owner was instructed to keep the stallion confined to a stall for at least 2 more months with a restricted daily short hand walk. Special casting methods for immobilization of a limb with an open joint luxation can tremendously improve the healing process.     

An anatomical study of the dorsal and ventral nasal conchal bullae and middle nasal conchae in normal Shetland ponies: Computed tomographic anatomical and morphometric findings

Equine paranasal sinuses are susceptible to inflammation. Insufficient drainage through the nasal passages and meatus may lead to the accumulation of inspissated purulent discharge. Particularly in ponies, these anatomical structures are suspected to be relatively small. To date, there are no reports considering the morphology of nasal conchal bullae in small horse breeds such as Shetland ponies. The aim of the present study was to evaluate the size of the conchal bullae and the medial nasal conchae of Shetland ponies and their relation to the skull dimension using computed tomography. Reconstructed images of healthy adult heads of Shetland ponies were used. Linear skull measurements as well as two cranial indices of the head dimensions were taken. Length, width and height of the dorsal and ventral conchal bullae and the medial nasal conchae were measured in relation to the skull and compared with the data of skulls of large breed horses. The anatomical proportions of pony heads were characterized by a smaller cranial index and a greater nasal index than those of large breed horses. Shetland ponies showed a longer cranial length compared with the nasal length. Heads are consistently smaller, and the relationship of the bullae to the head length was also smaller than those measured in large breed horses. A negative correlation between the head and bullae size was found. In conclusion, this study suggests that Shetland ponies have distinguishing proportions of the head. These findings are relevant for clinical examination and surgical treatment of equine sinus disease in those breeds.     

应用遗传算法优化设计汽车散热器

根据减少耗材的要求,本文将遗传算法应用于管带式汽车散热嚣的优化设计。提出了散热器芯体结构参数优化的方案,详细讨论了优化算法的步骤及流程,最后,通过实例表明该方法能得到较好的优化结果。