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971.
SJ Roman DA Chong Sit CM Boureau FX Auclin MM Ullern 《Canadian Metallurgical Quarterly》1997,81(8):673-676
AIM: To evaluate sub-Tenon's anaesthesia as an alternative to peribulbar anaesthesia. METHODS: 109 consecutive patients listed for various eye operations (including cataract, trabeculectomy, and vitrectomy) under peribulbar anaesthesia were operated on under sub-Tenon's anaesthesia instead. After topical anaesthesia a buttonhole was fashioned through the conjunctiva and Tenon's capsule 10 mm posterior to the limbus. 1.5 ml of lignocaine 2% was then delivered to the posterior sub-Tenon's space using a blunt cannula. The surgical procedure was performed immediately after the completion of the anaesthetic procedure. Chemosis, conjunctival haemorrhage, degree of akinesia, and pain scoring were analysed. RESULTS: There were no anaesthesia related complications. The administration of the block was painless for 99.1% of the patients. In all, 97.3% reported no pain during surgery. There was no akinesia when assessed just after the completion of the block and akinesia was limited when assessed after surgery. Chemosis and conjunctival haemorrhage were frequent but caused no intraoperative problems. CONCLUSION: Sub-Tenon's anaesthesia is an efficient and safe anaesthetic technique. It is a good alternative to peribulbar anaesthesia. 相似文献
972.
M Holzenberger ED Jarvis C Chong M Grossman F Nottebohm C Scharff 《Canadian Metallurgical Quarterly》1997,17(18):6974-6987
Neuronal replacement occurs in the forebrain of juvenile and adult songbirds. To address the molecular processes that govern this replacement, we cloned the zebra finch insulin-like growth factor II (IGF-II) cDNA, a factor known to regulate neuronal development and survival in other systems, and examined its expression pattern by in situ hybridization and immunocytochemistry in juvenile and adult songbird brains. The highest levels of IGF-II mRNA expression occurred in three nuclei of the song system: in the high vocal center (HVC), in the medial magnocellular nucleus of the neostriatum (mMAN), which projects to HVC, and to a lesser extent in the robust nucleus of the archistriatum (RA), which receives projections from HVC. IGF-II mRNA expression was developmentally regulated in zebra finches. In canary HVC, monthly changes in IGF-II mRNA expression covaried with previously reported monthly differences in neuron incorporation. Combining retrograde tracers with in situ hybridization and immunocytochemistry, we determined that the HVC neurons that project to area X synthesize the IGF-II mRNA, whereas the adjacent RA-projecting neurons accumulate the IGF-II peptide. Our findings raise the possibility that within HVC IGF-II acts as a paracrine signal between nonreplaceable area X-projecting neurons and replaceable RA-projecting neurons, a mode of action that is compatible with the involvement of IGF-II with the replacement of neurons. Additional roles for IGF-II expression in songbird brain are likely, because expression also occurs in some brain areas outside the song system, among them the cerebellar Purkinje cells in which neurogenesis is not known to occur. 相似文献
973.
In this paper, we study a bandwidth allocation strategy with state-dependent Bernoulli access (SDBA) and preemptive priority (PP) to serve wideband (WB) and narrowband (NB) traffics in wideband integrated networks. In this strategy, total bandwidth is divided into three regions, bandwidth for WB traffic, bandwidth for NB traffic and shared bandwidth. Under this environment, the minimum usable bandwidths for queueable NB traffic are controlled adaptively according to the system states. And the bandwidths used by the NB traffic are probabilistically preempted by a blockable WB traffic, when the number of NB messages waiting in the buffer is varying. The strategy is analyzed using the Neuts' matrix analytic approach. It shows better performance than other schemes which do not use SDBA and PP. In addition, the strategy with multiple buffer thresholds controls bandwidth allocation more dynamically and shows more performance build-up than the strategy with single buffer threshold. 相似文献
974.
An objective method for the assessment of levelness of dyed materials has been established. The relative unlevelness index developed takes account of the coefficients of variation of reflectance measured over the visible spectrum, with appropriate consideration of human vision sensitivity. It was found that the index demonstrated good correlation with the visual levelness assessment. 相似文献
975.
Compared to conventional sintering of Y2 O3 -doped ZrO2 using a slow heating rate of 10°C/min, microwave sintering and fast firing using a rapid heating rate of about 500°C/min resulted in lower final sintered densities. It is attributed to the residual chlorine in commerical zirconia powders manufactured by the chloride process. By calcining at 1100°C for 1 h to remove residual chlorines from the powder compacts, near full densities (>99% of theoretical) could be obtained by both fast firing and microwave sintering. 相似文献
976.
P Grübel JS Hoffman FK Chong NA Burstein C Mepani DR Cave 《Canadian Metallurgical Quarterly》1997,35(6):1300-1303
The mode of transmission of Helicobacter pylori is unknown. Since viable bacteria have been shown to be excreted in feces from infected individuals and houseflies habitually develop and feed on excrement, we hypothesized that flies ingest and harbor H. pylori and, in turn, contaminate the human environment. This study examined the possible vector potential of houseflies (Musca domestica) for H. pylori. Caged houseflies were exposed to freshly grown H. pylori on agar plates. After a 6-h feeding period, the plates were removed and were replaced with sterile petri dishes containing a droplet of sterile brucella broth. At regular intervals, small numbers of houseflies were removed for microbiological and histological analysis, and the petri dishes were replaced with fresh sterile plates with fresh drops of brucella broth. The flies' bodies, the flies' dissected alimentary tracts, and excreta on the petri dishes were cultured for H. pylori, whose identity was confirmed by the urease, catalase, and oxidase reactions and Gram staining. In contrast to control flies, viable H. pylori could be isolated from external surfaces for up to 12 h and from gut and excreta for as long as 30 h after the initial feeding period. After 30 h other gram-negative bacteria overgrew the cultures of samples from all locations tested, rendering the selective culture of H. pylori colonies impossible. Histological analysis revealed Helicobacter-like organisms in the gut lumen and attached to intestinal epithelial cells. We conclude that houseflies can harbor viable H. pylori on their bodies and in their intestinal tracts. They are also able to disseminate viable H. pylori in excreta, and they may therefore present a significant reservoir and be a vector in the transmission of H. pylori. 相似文献
977.
Chong Peter H. J. Leung Cyril 《International Journal of Wireless Information Networks》2003,10(1):17-31
Reuse partitioning (RP) is a simple technique that can be used to increase the traffic capacity in a cellular system. With RP, a cell is divided into several concentric regions, each associated with a different cluster size. In this article, a traffic model is developed to analyze the impact of mobile users on a two-region RP system using fixed channel assignment. The influence of user speed and cell size on the new call blocking probability, Pb, and the call dropping probability, Pd, is investigated. A simpler model that can be used to estimate Pb and Pd in some cases is described. The effect on system capacity of reserving some channels for handoff calls is also studied. It is found that even though prioritized handoff can reduce Pd, it may also degrade the capacity. The accuracy of the analysis is verified using simulation for three mobility models. 相似文献
978.
Joong Kil Park Indira V. Samarasekera Brian G. Thomas U. Sok Yoon 《Metallurgical and Materials Transactions B》2002,33(3):425-436
Three-dimensional (3-D) finite-element thermal-stress models have been developed to predict temperature, distortion, and residual
stress in the mold of continuous casters of thin steel slabs, comparing both funnel-shaped and parallel molds. The mold shape
and high casting speed leads to higher mold temperatures and shorter mold life than in conventional slab casters. This study
investigates heat flux and the effects of mold shape on distortion and cracking of the thin-slab mold. In Part I of this two-part
article, mold wall temperatures measured in the plant were analyzed to determine the corresponding heat-flux profiles in thin-slab
molds. This data was then used in an elastic-visco-plastic analysis to investigate the deformation of the molds in service
for the two different mold shapes. The model predictions of temperature and distortion during operation match plant observations.
During operation, the hot-face temperature reaches 580 °C and heat flux varies from 7 to 4.5 MW/m2 when casting at 3.6 m/min. The copper plates bend toward the steel, with a maximum outward distortion of about 0.3 mm. This
occurs just above the center of the wide faces and is smaller than the distortion of a conventional slab mold. 相似文献
979.
980.