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11.
Visible quantum cutting in LiGdF4:Eu3+ through downconversion 总被引：1，自引：0，他引：1
For mercury-free fluorescent lamps and plasma display panels, alternative luminescent materials are required for the efficient conversion of vacuum ultraviolet radiation to visible light. Quantum cutting involving the emission of two visible photons for each vacuum ultraviolet photon absorbed is demonstrated in Eu3+-doped LiGdF4 with the concept of downconversion. Upon excitation of Gd3+ with a high-energy photon, two visible photons can be emitted by Eu3+ through an efficient two-step energy transfer from Gd3+ to Eu3+, with a quantum efficiency that approaches 200 percent. 相似文献
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Brachycephalic feline noses: CT and anatomical study of the relationship between head conformation and the nasolacrimal drainage system 总被引：1，自引：1，他引：0
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M Boller K Kelers MA Stevenson KD Winkel S Hardjo J Heller PR Judge HM Ong AM Padula C Reddrop LCP Santos CR Sharp L Smart KL Swindells D Tabrett JR Wierenga 《Australian veterinary journal》2020,98(9):442-448
SnakeMap is a national cloud-based, veterinary snakebite registry. It was designed to prospectively collect data of the clinical circumstances and temporospatial information on cases of snake envenomation in dogs and cats. We herein introduce the project and summarise the data from the first 4 years of SnakeMap. The registry is a veterinary community-based online database allowing case entry from veterinary hospitals across Australia. Registry data comprise hospital characteristics, patient characteristics, envenoming snake type, treatment and outcome variables, including time and geolocation of the snake bite. We present summative information on select key variables from the SnakeMap registry (1 July 2015 to 30 June 2019). Twenty-eight hospitals from 6 states/territories entered 624 cases into the registry, including 419 dogs (67%) and 205 cats (33%). Bite time was available in 216 animals of which 90 (42%) were reported to be bitten in the 3 hours between 03:00 pm and 05:59 pm; median bite to presentation interval was 60 (interquartile range [IQR] 30, 211) minutes in dogs and 95 (IQR 41, 238) minutes in cats. Bites occurred in the owner's yard in 356 dogs (85%) and 53 cats (26%). A snake venom detection kit was used in 172 cases (28%) and antivenom was administered in 523 cases (85%). Most animals (n = 534, 88%) survived to discharge (median hospitalisation of 25 [IQR 16, 62] hours). SnakeMap effectively collects relevant clinical data from dogs and cats with presumed snake bite and provides locally specific information on the epidemiology of snake envenomation in small animals. 相似文献
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To answer the many open questions concerning the development of the horse's ovary, first the prenatal development was investigated. It resulted that follicles derive from the germinal epithelium and its cords, whereas the Leydig cells and the rete blastema originate from the mesonephros. In the second third of pregnancy the Leydig cells undergo an enormous proliferation, in the last third they degenerate. However this degeneration is not connected with the postnatal development of the ovulation groove. 相似文献
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This study classifies the segments of the dog claw and presents a new conception to define crown and wall segments that deviates from the common statements in literature. The perioplic segment extends along the internal surface of the claw fold (vallum). The crown segment lies in the unguicular groove, and there in a semicircular zone. In the crown segment there is development of horn tubuli, but these lose their tubular structure before they have reached the top of the claw. The wall segment, adjacent distally, comprises a dorsal ridge, and lateral surfaces proximally and distally which are all marked by superficial lamellar-shaped surface configurations. The sole segment shows desquamative soft horn and is situated between the free margin of the wall segment palmar/plantar to the unguicular process. The new conception of homology of dog claw distinguishes between main and secondary criteria. The main criterion is the epidermal and dermal configuration. Secondary criteria are the typical horn products (for example perioplic horn) and dimension, shape and topography of segments. The sterile/fertile-bed theory, which was believed to be the determining factor for the classification of the dog claw, is neither the proper method to define the individual segments nor to judge the rate of cornification. 相似文献
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The aim of this study was to establish an in vitro model that permits in vitro infection of bovine skin with Treponema spp . and enables to study the role of treponemes in the pathogenesis of digital dermatitis (DD). In all experiments, incubation with T. denticola or T. brennaborense was carried out simultaneously. Keratinocytes obtained from the claw were cultivated on cover glasses without antibiotics until they reached sub-confluence. Then they were incubated with OMIZ Pat medium containing treponemes for up to 96 h. Every 24 h two cover glasses were fixed and stained with the DAPI method. Skin explants were obtained from typical sites of DD lesions. First the explants were maintained in medium with antibiotics to eliminate bacterial contamination. Subsequently, they were rinsed thoroughly with medium without antibiotics and incubated with Treponema suspensions for 48 h. The treponemes stayed vital under culture conditions for even up to 96 h. They were still showing their typical spiral shaped morphology and adhered to the cultured keratinocytes at all time points. With prolonged incubation time cultured cells began to show morphologic damage and some cells detached from the cover glasses. Light and electron microscopical investigations of the explants revealed that treponemes were adhering to the surface of the epidermis. They were visible in often-enlarged intercellular spaces. In addition treponemes could be detected in deep epidermal layers and in very high concentrations in the dermis. In periodontal disease, spirochetes were observed in enlarged intercellular spaces. Our results support these findings suggesting that treponemes invade the deeper claw tissue via the intercellular spaces of the epidermis. We suggest that the enlargement of the intercellular spaces can improve an increased infection of deeper tissue layers and facilitates the way for infection with other anaerobic bacteria. 相似文献
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Comparative anatomical studies on transepithelial fluid migration into the lumen of the cloaca in birds In the rooster the fluid migration originates principally from lymph capillaries and ends in the interstitium of the lymphfolds. In the male duck, coot and pigeon this phenomenon occurs in a corresponding zone of transudation. In these birds the fluid migration originates principally in blood capillaries, however. From the interstitium the fluid passes through intercellular spaces of the epithelium into the lumen of the cloaca where it appears as a transparent fluid. In all examined species immunocompetent cells migrate into the cloaca with the fluid. These cells produce the immunoglobulins which have been found in the transparent cloacal fluid of the rooster. 相似文献
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Bragulla H Hirschberg RM Schlotfeldt U Stede M Budras KD 《Anatomia, histologia, embryologia》2004,33(5):263-272
The adrenal gland is a vitally important endocrine gland that occupies a central role in the regulatory mechanisms of the body metabolism. Environmental stress factors lead to permanent strain and overload of the body resulting in structural alterations of the adrenals that in turn are followed by hormonal imbalances. This leads to an increased susceptibility to bacterial and viral diseases. The recurrence of numerous fatalities in the different seal populations of the North Sea (during the years 1988, 1989 and 2002), of the Baikal Lake and Caspian Sea (during the years 2000 and 2001) were the motive for a morphological investigation of the species-specific structure of the adrenal gland of the common seal in order to differentiate environmental stress-induced pathological alterations from the physiological structure of this organ. The study was based on adrenals of 112 common seals (Phoca vitulina vitulina) using light microscopic and transmission and scanning electron microscopic methods. The phocine adrenal gland displays several structural characteristics. Originating from the connective tissue organ capsule, narrow and broad septa intersperse the adrenal cortex. These septa contain blastemata as a reserve for the regeneration of hormone-producing cortical cells. Such blastemata are also occurring in the form of an intermediate zone in between the zona glomerulosa and zona fasciculata in the phocine adrenal cortex. Another species-specific characteristic is an inverse part of the adrenal cortex encircling the central vein of the organ. These structural features have to be considered in assessment and definition of pathological alterations of the adrenals as observed in the form of exhausted blastema cell pools in the adrenocortex of seals perished in the mentioned phocine mass mortalities. 相似文献