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81.
The motion of guanine particles was recorded by video to visualize transitional flow phenomena in models of a proximal side-to-end anastomosis. Close examination of successive video fields revealed that above a critical Reynolds number, particles were periodically shed into the graft from a vortex situated near the anastomosis heel, and this disturbed the flow patterns in the graft causing vortex shedding to occur near to the toe of the anastomosis. The images clearly demonstrated that periodic flow structures propagated distally along the graft for over 15 tube diameters from the proximal anastomosis. The frequency of the vortex shedding was found to increase with Reynolds number. Under pulsatile conditions, the primary vortex at the heel of the anastomosis became unstable during the deceleration phase of the flow cycle and particles were shed downstream into the graft. Although it was possible briefly to observe the characteristic banded structure in the bypass graft, the flow patterns were highly three-dimensional and were quickly broken up by the accelerating flow. Dynamic flow visualization using guanine particles was found to be a complementary technique to particle tracer flow visualization and was highly effective in identifying transitional flow phenomena and the mass transport mechanisms associated with them. 相似文献
82.
JD Edinger AI Fins RJ Sullivan GR Marsh DS Dailey TV Hope M Young E Shaw D Carlson D Vasilas 《Canadian Metallurgical Quarterly》1997,20(12):1127-1134
Complaints of daytime dysfunction are common among chronic insomniacs, but laboratory comparisons of insomniacs and age-matched and gender-matched normal controls have generally failed to document these complaints. However, a few studies, which allowed subjects to sleep in their homes on the nights before daytime testing, have shown some relative diurnal deficits among insomniacs. The current study compared the effects of nocturnal laboratory and home polysomnogram (PSG) studies on subsequent daytime test results among older insomniacs and normal sleepers. Insomniacs (n = 32) and normal sleepers (n = 32) were randomly assigned to first undergo three nights of nocturnal PSG monitoring either in the sleep laboratory (16 insomniacs, 16 normal sleepers) or in their homes (16 insomniacs, 16 normal sleepers). Following the third night of PSG monitoring, subjects spent 1 day in the sleep laboratory, where they completed a four-trial multiple sleep latency test along with four trials of a computer-administered performance test battery. Results showed that insomniacs, as a group, were slightly, albeit consistently, sleepier than were normal sleepers following nights of home sleep monitoring, but a reverse of this trend was found among subjects who underwent nocturnal laboratory PSG before daytime testing. Furthermore, normal sleepers showed faster reaction times on a signal detection task than did insomniacs within the subgroup who underwent home PSGs prior to such testing. However, within the subgroup that underwent nocturnal laboratory PSGs, insomniacs' signal detection reaction times were significantly faster than those shown by normal sleepers. Results provide some support for the speculation that the nocturnal PSG monitoring site, used as a precursor to daytime testing, may systematically affect daytime comparisons between insomniacs and matched controls. Moreover, these results suggest that the use of home-based nocturnal PSG monitoring prior to daytime testing may provide an enhanced understanding of insomniacs' diurnal complaints. 相似文献
83.
Progenitor and pluripotent stem cells reside within connective tissue compartments. They are also present in granulation tissue. This study examined the effects of treating these two cell populations with eight bioactive factors. Cells were assayed for DNA content as a measure of proliferation and for tissue-specific phenotypic markers as measures of lineage progression and lineage commitment. Platelet-derived endothelial growth factor and insulin-like growth factor-II did not induce proliferation in either population. However, dexamethasone, insulin, insulin-like growth factor-I, muscle morphogenetic protein, platelet-derived growth factor-AA, and platelet-derived growth factor-BB stimulated proliferation in one or both cell populations. Platelet-derived growth factor-BB was the most potent stimulator of proliferation in either population. Phenotypic expression markers were induced in the progenitor cells by insulin, insulin-like growth factor-I, insulin-like growth factor-II, dexamethasone, and muscle morphogenetic protein. However, only dexamethasone and muscle morphogenetic protein induced phenotypic expression markers in the pluripotent cells. Platelet-derived endothelial cell growth factor, platelet-derived growth factor-AA, and platelet-derived growth factor-BB did not induce phenotypic expression markers in progenitor or pluripotent cells. This study suggests the potential for using progenitor and pluripotent cells as an in vitro model to ascertain the effects of various bioactive factors on stem cells potentially involved in tissue maintenance and repair. 相似文献
84.
NE Zakharova NP Vaneeva NE Iastrebova NG Kalina MM Tokarskaia VV Sergeev NV Tsvetkova NN Ovechko TV Sokolova 《Canadian Metallurgical Quarterly》1998,(6):82-83
A study was made into the functional status of hypophysis, adrenal cortex, ovaries, and thyroid gland in patients with kraurosis and leukoplakia vulvae. The above patients demonstrated profound disturbances in the system hypophysis-ovaries, that attest to the need for applying corrective therapies to treat the disturbed hormonal homeostasis. 相似文献
85.
Organ cultures of rodent and human prostate glands have shown marked differences in their morphological response to testosterone. In this study, explants from 19 canine prostate glands were cultivated for a minimum of 9 days in Trowell's T-8 medium. Groups of explants were exposed to media containing from 0.05 to 100 mum testosterone. While the higher testosterone levels (50 and 100 mum) markedly decreased explant viability, explants cultivated at lower levels (0.05 to 5 mum) appeared similar to control explants in testosterone-free Trowell's T-8 medium. Atmospheric mixtures containing either 95% or 50% oxygen were equally effective. Shortly after the cultures were initiated, large amounts of secretory product were liberated into the lumen. After 9 or more days in vitro, glandular epithelium appeared cuboidal and never revealed the acid phosphatase-rich secretory granules seen in the preculture control. However, the epithelium exhibited an increase in alkaline phosphatase and lipid content following cultivation. 相似文献
86.
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88.
Since it covers the lateral wall of the mastoid air system, the suprameatal triangle is of importance to otologic surgeons during mastoidectomy. Because of this clinical importance, topographic anatomy of the suprameatal spine and depression was studied on Anatolian skulls. In all, 363 male and 231 female skulls were studied. The most prevalent type of suprameatal spine resembled a crest and was found in both sexes on the right (77.6%) and left (80%) sides. The absence of a suprameatal depression was significantly higher in females (right 9.1%; left 8.7%) than in males (right 1.7%; left 2.5%). Suprameatal depressions were mostly shallow in female subjects, but were mostly observed in males to be at a medium depth or deep. 相似文献
89.
A review of 76 Southampton children with Henoch-Sch?nlein purpura has confirmed that there is no evidence of a streptococcal aetiology in the majority of cases of this disease. Among these patients the frequency of preceding respiratory infection of all kinds was only 7 percent greater than that in controls. Data on month of admission in four areas of England and Scotland show that the incidence of the disease is lowest in the June-August period. Contrary to previous findings there is no marked peak of incidence in any single month. 相似文献
90.
It was demonstrated that both in vitro and in intravenous injection of prostaglandin F2alpha there occurred labilization of the membranes of sclera and ciliary body lysosomes, in difference from the cornea in rabbits. Glycosidase activity appeared in the vitreous body under the effect of prostaglandin, which was absent under normal conditions. 相似文献