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81.
82.
VL Nimgaonkar R Ganguli WA Rudert C Vavassori BS Rabin M Trucco 《Canadian Metallurgical Quarterly》1993,8(3):199-209
The present study investigated the relationship between the time of nocturnal onset of urinary 6-sulfatoxymelatonin (aMT6s) secretion, and the timing of the steepest increase in nocturnal sleepiness ("sleep gate"), as determined by an ultrashort sleep-wake cycle test (7 min sleep, 13 min wake). Twenty-nine men (mean age 23.8 +/- 2.7 years) participated. The ultrashort sleep-wake paradigm started at 0700 hr after a night of sleep deprivation and continued for 24 hr until 0700 hr the next day. Electrophysiological recordings were carried out during the 7-min sleep trials, which were then scored conventionally for sleep stages. Urinary aMT6s was measured every 2 hr. The results showed that the timing of the sleep gate was significantly correlated with the onset of aMT6s secretion. These results are discussed in light of the possible role of melatonin in sleep-wake regulation. 相似文献
83.
M Pazianas M Zaidi CL Huang BS Moonga VS Shankar 《Canadian Metallurgical Quarterly》1993,192(3):1100-1105
We demonstrated previously that osteoclasts possess a divalent cation-sensitive "receptor", the Ca2+ receptor. Activation of the Ca2+ receptor by the surrogate cation Ni2+ was shown to elicit an increase in cytosolic [Ca2+] to a peak value followed by an exponential decline. In the present study we examined the influence of surface membrane voltage on the kinetics of Ca2+ receptor inactivation. The K+ ionophore, valinomycin was applied to intercept the declining phase of the cytosolic [Ca2+] transient elicited by application of between 50 microM- and 5 mM-[Ni2+]. This resulted in a sustained elevation of cytosolic [Ca2+] or even a 'hump' followed by a gradual decline. Such a kinetic alteration persisted in a Ca(2+)-free solution, but was abolished in high extracellular [K+] (105 mM). Thus, we demonstrate for the first time to our knowledge, a modulatory effect of membrane potential on the function of the osteoclast Ca2+ receptor. 相似文献
84.
GS Alexopoulos BS Meyers RC Young S Mattis T Kakuma 《Canadian Metallurgical Quarterly》1993,150(11):1693-1699
OBJECTIVE: The goals of this longitudinal investigation were 1) to study the rate of development of irreversible dementia in elderly depressed patients with a dementia syndrome that subsided after improvement of depression and 2) to compare it with that of depressed, never-demented patients. METHOD: The subjects were 57 elderly patients consecutively hospitalized for major depression. At entry into the study, 23 subjects also met criteria for "reversible dementia," while 34 were without dementia. After a systematic clinical evaluation, the subjects were followed up at approximately yearly intervals for an average of 33.8 months. RESULTS: Irreversible dementia developed significantly more frequently in the depressed group with reversible dementia (43%) than in the group with depression alone (12%). Survival analysis showed that the group with reversible dementia had a 4.69-times higher chance of having developed dementia at follow-up than the patients with depression alone. No clinical characteristics at entry into the study were found to discriminate the subjects who developed irreversible dementia during the follow-up period from those who remained nondemented. CONCLUSIONS: These findings suggest that geriatric depression with reversible dementia is a clinical entity that includes a group of patients with early-stage dementing disorders. Therefore, identification of a reversible dementia syndrome is an indication for a thorough diagnostic workup and frequent follow-ups in order to identify treatable neurological disorders. 相似文献
85.
86.
A lot of older adults try to learn to use computers and might use different ways to perform a computer task compared to younger people. Fifteen healthy young and 15 healthy older adults participated in this study and all performed a series of mouse tasks. A three dimensional motion capture system and electromyographic analysis were used to obtain kinematic and kinetic data during performing the computer tasks. Three-way analysis of variance with repeated measures on task and time factors was used to analyze all dependent measurements. Older adults had higher RMS of forearm muscles compared to the young adults. The RMS of the finger extensor was highest when performing a dragging task. Compared with young adults, the older adults had greater cranial-cervical angle and neck flexion, but smaller head flexion, shoulder angle, elbow angle and ulnar deviation. Consequently, the older adults might have a greater risk of developing musculoskeletal disorder. 相似文献
87.
We have followed the growth of stature, sitting height, skinfolds, muscle widths measured radiologically, and skeletal maturity in growth hormone-deficient patients in whom hGH was given and withheld in alternating three-month periods throughout puberty (referred to as "off-hGH" and "on-hGH" periods). Six boys and four girls had true isolated GH deficiency and developed puberty spontaneously. Two boys had gonadotrophin deficiency plus GH deficiency, and five boys had multiple deficiencies; in these boys the signs of puberty were induced by hormone treatment. Boys with true isolated deficiency grew about two-thirds as much in height in the off-hGH periods as in the on-hGH periods; their total gain in height during the adolescent spurt would have been about 20 cm, instead of 30 cm, if hGH had been discontinued at the beginning of puberty. The effect of hGH was entirely on growth in leg-length, however, which virtually ceased during the off-hGH periods. Growth in sitting height altered little when hGH was withdrawn. Growth in limb muscles, however, was GH dependent throughout puberty; during the majority of periods when hGH was withheld, muscle was actually lost; this occurred in the boys who were receiving large doses of testosterone as well as in those producing their own normal amounts. Subcutaneous fat diminished when hGH was given and increased when it was withdrawn; this occurred independently of administration of testosterone. There was little evidence that growth of pubic and axillary hair progressed faster during on-hGH periods, except perhaps in patients with multiple deficiencies. There was some evidence, however, that bone age progressed less rapidly during on-hGH periods than during off-hGH periods in the patients with isolated deficiency. The results in the girls agreed with those in boys so far as stature was concerned, but the relationship with sitting height and leg length appeared to be different; the reasons for this are discussed. We conclude that all children with GH deficiency should continue on treatment with hGH throughout puberty, ideally until growth ceases. 相似文献
88.
Te-Hua Fang Yu-Jen Hsiao Yee-Shin Chang Yen-Hwei Chang 《Materials Chemistry and Physics》2006,100(2-3):418-422
In this study, the photoluminescence (PL) spectra of europium-doped potassium niobate (KNbO3) crystallites prepared by a vibrating milled solid-state reaction method were studied. X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical spectral analysis (luminescence excitation, emission spectra and time-resolved spectra) were used to characterize the KNbO3:Eu3+ powders. The results of the XRD revealed that the powders remained as a single orthorhombic structure at doping concentrations below 3 mol%. A second phase of EuNbO4 begins to appear at 5 mol%. The 5D0–7F1 (593 nm) and 5D0–7F2 (614 nm) emission characteristics of Eu3+ appear at a quenching concentration of above 3 mol%. The Commission Internationale d’Eclairage (CIE) chromaticity coordinates of a Eu:KNbO3 host excited at λex = 400 nm and λex = 466 nm wavelengths, both presented a red-shift when increasing the Eu3+ ion doping. The lifetime of the Eu3+ ion decreased as the doping concentration was increased from 1 to 7 mol%. 相似文献
89.
A method and a program (tcq) in FORTRAN 90 based on Gaussian quadrature are developed to compute the terrain correction (TC). TCs were determined on 1010 benchmarks using the Gaussian quadrature, prism and FFT methods using a 3″×3″ elevation grid for the inner zone and a 30″×30″ elevation grid for the outer zone. In order to achieve a 0.1 mgal accuracy in TC while reducing the computing time, the best inner and outer radii for TC computation are 20 and 200 km, respectively. The Gaussian quadrature is a highly accurate numerical integrator and yields results that outperform those from the prism method and the FFT method. The singular problem of the kernel function in TC is treated by considering the innermost zone effect, which can be expressed as a complete elliptic integral of the first kind. The innermost zone effect must be taken into account if the required accuracy of TC is at a 1-mgal level. 相似文献
90.
Jiin‐Jou Lih Chih‐Feng Sung Chun‐Huai Li Tiao‐Hung Hsiao Hsin‐Hung Lee 《Journal of the Society for Information Display》2004,12(4):367-371
Abstract— The characteristics of OLED backplanes including the intrinsic properties of a‐Si TFTs and LTPS TFTs will be reviewed. While LTPS TFTs reveal satisfactory stability in AMOLED‐display applications, a‐Si AMOLEDs show better uniformity and are capable of driving OLEDs. However, the stability of a‐Si TFTs under long‐term operation is still unacceptable and remains to be the key issue constraining the commercialization of a‐Si TFT AMOLEDs. 相似文献