Grouped, stacked rods and tapeta lucida in the retina of Japanese anchovy Engraulis japonicus

ABSTRACT: Morphology of the photoreceptor cells and tapetum of the Japanese anchovy Engraulis japonicus was studied by histologically and by chemical analysis. The Japanese anchovy has a duplex retina. The cones form parallel rows consisting of alternately placed long cones and bifid cones. Both types of cones are intimately associated and form triple units that are regularly spaced along the row of cones. The rods are grouped and stacked. This fish has a retinal tapetum lucidum composed of guanine and hypoxanthine. Three structures of the tapetum lucidum were recognized: platelet, diamond and rod types. Photomechanical changes include movements of the photoreceptor cells and the retinal tapetum. The retina of the Japanese anchovy is thought to be highly sensitive and well adapted to a dim light environment.     

基于动态边界的双吸离心泵叶片渐进磨损及泵性能预测

过流边界形态随磨损时间的变化对客观真实地反映双吸离心泵磨损特性及磨损形貌至关重要。采用欧拉-拉格朗日方法,配合磨损壁面几何重构的动态边界法,对黄河平均含沙量及粒径下甘肃省景泰川泵站双吸离心泵进行固液两相流计算,结合实验数据,预测了该泵叶片渐进磨损特性,分析了叶片磨损机理及壁面几何形貌变化对泵性能影响。结果表明：以冲击角函数最大值对应冲击角α0为阈值,小于α0磨损形貌呈类圆形凹坑,大于α0磨损形貌呈沟槽状,冲击角在50°~75°范围且冲击速度高的叶片区域磨损率大,叶片磨损程度严重;根据该泵水力性能损失率变化特性,将预测期划分为3个阶段,磨损率在初期增长率最大,但在数量级上远小于中、后期,使前1000h磨损阶段扬程损失率、效率损失率、叶片质量损失率均小于其他阶段;上述3个参数的增长均呈初期慢、中期快、后期减缓的趋势,最大增长率均在磨损中期,参数变化曲线斜率分别为1.51×10-3、1.97×10-3、4.12×10-3,在1000~6000h磨损时长范围内,磨损导致双吸离心泵性能下降最快。     

A comparison of retinol, retinal and retinyl ester concentrations in larvae of Atlantic halibut (Hippoglossus hippoglossus L.) fed Artemia or zooplankton

Atlantic halibut (Hippoglossus hippoglossus L.) larvae were fed enriched Artemia or zooplankton in duplicate tanks from 0 to 60 days after first‐feeding. Both diets and the larvae were analysed for vitamin A (VA) in order to confirm earlier findings, in which Artemia fed larvae had lower levels of VA compared with larvae fed zooplankton. Furthermore, we wanted to investigate the composition of the retinoids in the larvae. The results showed that Artemia and zooplankton contains low levels of VA, probably too low to sustain the assumed requirement. Nevertheless, larvae fed Artemia had the same level of retinal and retinol as larvae fed zooplankton. We found a significant lower level of retinyl esters in larvae fed Artemia. The total VA level was lower in larvae fed Artemia only at the end of the feeding trial after the onset of metamorphosis. Our conclusion is that feeding Artemia to Atlantic halibut larvae is not likely to cause VA deficiency.     

THE DEVELOPMENT OF COMPUTER AIDED NORM OF WORKING HOUR PLANNING SYSTEM

Based on Group Technology, part families of the norm of working hour are formed according to the similarity among components. With the progressive regerssion, the models of the norm of working hour are built for every part family. A computer aided norm model building program and a computer aided norm of working hour planning system are developed. The system is successfully integrated with CAD/CAPP system. Some examples of the model building and calculation results are illustrated as well.     

干旱胁迫及复水对棉花幼苗根系氮代谢的影响

以不同耐旱型棉花品种"新陆早7号"和"新陆早24号"幼苗为试材,研究持续干旱胁迫及复水对棉花幼苗根系氮代谢关键酶活性、可溶性蛋白质、总氮和游离氨基酸含量的影响。结果显示:随着干旱胁迫天数的增加,"新陆早7号"和"新陆早24号"硝酸还原酶(NR)活性与对照相比分别降低45.03%和62.37%,谷氨酰胺合成酶(GS)活性分别降低53.22%和67.23%,谷氨酸合成酶(GOGAT)活性分别降低54.92%和79.28%,谷氨酸脱氢酶(GDH)活性在处理4d达到最大值,5d时下降,可溶性蛋白质含量分别增加了87.38%和77.12%,总氮含量分别增加了14.01%和12.14%,铵离子含量分别增加了232.02%和263.47%。干旱胁迫使"新陆早7号"在胁迫前期游离氨基酸含量增加慢,后期增加快,"新陆早24号"游离氨基酸含量的变化趋势与"新陆早7号"则相反。复水后,"新陆早7号"NR活性、GS活性、GOGAT活性和GDH活性恢复较快,内肽酶活性和游离氨基酸、铵离子、可溶性蛋白质和总氮含量下降也较快。试验表明,耐旱型棉花品种具有较强的铵离子同化能力,可增加渗透调节物质游离氨基酸含量,特别是脯氨酸含量,有助于增强其耐旱性。     

Chronic progressive lymphoedema in draught horses

The objective of this review was to summarise and evaluate the current state of knowledge about chronic progressive lymphoedema in draught horses. Clinical signs of this multifactorial disorder are mainly restricted to the lower limbs, comprising progressively deteriorating skin, swelling and deformation. Although typical lesions were first reported at the beginning of the 20th century, chronic progressive lymphoedema was recognised as a specific syndrome only in 2003, and since then research has driven forward. Despite the high prevalence in some breeds and the serious economic impact, the pathogenesis is not fully understood, and the available treatment options remain symptomatic and noncurative. There is a need to improve diagnostic techniques and to develop selection tools.     

A case of primary choroidal malignant melanoma in a cat

This report describes the clinical presentation, diagnosis, histological lesions, and prognosis of a primary choroidal malignant melanoma in a 15‐year‐old cat. The animal was presented for unilateral blindness. On ocular examination, a raised pigmented mass protruding from the posterior pole into the vitreous body was observed by diffuse transillumination and indirect ophthalmoscopy. Ocular ultrasound and computer tomography (CT) scan confirmed localization of the tumor to the posterior segment. The diagnosis of primary choroidal melanoma was confirmed by histopathology after enucleation. To our knowledge, this is the first reported case of a feline malignant melanoma with a primary choroidal localization without iris involvement.     

Immunopathology of the eye: Purification of canine retinal “S” antigen

Canine retinal S antigen has been purified to study the retinal progressive atrophy of the dog. The purified antigen will be used to detect, by the ELISA technique, specific autoantibody in dogs with ocular diseases.     

Fluorangiographic study of the ocular fundus in normal horses

Purpose:  To describe the protocol and appearance of fluorescein angiography (FA) in normal horses.
Animals:  A total of 25 healthy horses aged between 5 and 15 years.
Materials and Methods:  The horses were sedated with 15 µg/kg detomidine and 50 µg/kg butorphanol and dilated with topical tropicamide 1%. All angiograms were recorded after intravenous bolus injection of 10 mg/kg of fluorescein sodium solution.
Results:  Two successive angiographic phases could be discerned: the choriopapillary phase, starting at 46.95 ± 9.48 s, and the retinal vascular phase, starting at 47.79 ± 10.38 s. The retinal vascular phase was divided in three parts: filling phase , maximum fluorescence point , and fading phase . During the filling phase, the dye progressed into the retinal vessels, obtaining maximum fluorescence at 59.79 ± 10.39 s, termed the maximum fluorescence point. The fading phase started immediately following the maximum fluorescence point. During this phase, vascular fluorescence decreased to complete reduction at 74.76 ± 9.81 s. Also, areas of delayed choroidal filling, the presence of short retinal vessels in the ventral region of the optic disc, and a particular filling of the optic disc were also observed.
Conclusions:  The normal angiographic sequence was described in horses. FA may be a useful method for studying the integrity of the blood–retinal barriers in horses.