Wide angle attachment for fundus cameras.
A simple and inexpensive method for increasing the angle of view of existing fundus cameras used for fluorescein angiography is described. The addition of a concavo-convex positive lens extends the usefulness of the camera and contributes to the efficiency of diagnosis.
Vascularity of mammalian retinae : a comparative anatomical study of mammals with and without intraretinal blood vessels
The physical requirements necessary for the perception of light have produced peculiar 
adaptions to the way in which the eye is nourished. In many mammals there is a dual blood 
supply to the retina derived from both choroidal and intraretinal circulations. Interestingly, 
some species have only a choroidal blood supply. This study has addressed the coping 
strategies of those retinae which lack intraretinal blood vessels. Placental guinea pigs and 
diprotodont marsupial brushtail possums and sugar gliders, all of which lack retinal circulation 
(avascular retinae) have been compared with placental rats and polyprotodont marsupial 
quolls, Virginia opossums and Tasmanian devils, all of which possess intraretinal blood 
vessels (vascular retinae). Functional angiographic study has documented vascular patterns 
and demonstrated the close arteriovenous pairing within the polyprotodont marsupial retina. 
Avascular retinae are thinner than their vascular counterparts. The difference is not great 
(170Am versus 220gm): The limitation in thickness is borne by most retinal laminae but more 
so by those layers furthest from the choroidal supply. Morphological analysis suggests that 
spatial visual acuity is comparable in vascular and avascular species. Corrosion casting and 
microscopy of the ocular vasculature has shown that the choroid of the avascular species 
examined has no obvious morphological specialisations which might offset the lack of retinal 
vessels. However, the metabolic pathways within the inner layers of avascular retinae are 
markedly different, with limited oxidative metabolism as indicated by the activity of the 
mitochondrial enzyme, cytochrome oxidase. However, ATPase activity, as a measure of 
overall energy consumption, is known to be high within the inner layers of the avascular 
guinea pig retina (Ueno et al. 1981). This suggests that low cytochrome oxidase activity need 
not mean limited functional metabolic capacity. As a morphological accompaniment of 
oxidative activity, ultrastructural analysis would suggest that mitochondrial numbers may be 
reduced within the inner retinal layers of avascular retinae when compared with similar 
regions in vascular retinae. Central to these observations is the clinical question of whether 
the human retina can mimic the coping strategies of avascular retinae following pathological 
disruption of its intrinsic vasculature.
Transient nonlinear thermal stability analysis of metro cable under pulse power
The load of metro cable system varies a lot from morning rush hours to the evening closure time. With many trains hopping in the rush hours, the long term and economical short term thermal stability become a big issue as a result of the large difference between thermal time constant and the electrical time constant of cable. Based on a 10kV three-core XLPE metro power cable model, the theoretical thermal capacity was calculated according IEC standard. Then, a Finite Element Method (FEM) was employed to analyze the transient electro-thermal phenomena, taking into account various types of power loss in cable system and the non-linear electrical conductivity of the conductor. Finally, the thermal distribution inside the cable was presented as a function of time, and the maximum thermal capacity was predicted in metro cable.