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31.
目的探讨多壁纳米碳管增强义齿基托树脂(MWCNTs/PMMA)复合材料的生物学性能。方法进行MWCNTs/PMMA复合材料制备,参照ISO7406技术报告相关标准,对MWCNTs/PMMA复合材料生物安全性进行体内及体外试验.包括细胞毒性试验、急性全身毒性试验及口腔黏膜刺激试验.评价复合材料的生物学性能。结果细胞毒性试验评价级别为1级.无明显细胞毒性作用:急性全身毒性试验未见任何急性毒性反应:口腔黏膜刺激试验未见异常组织学反应。结论MWCNTs/PMMA复合材料具有良好的生物安全性.安全无毒。 相似文献
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Dentures are frequently fractured owing to the poor fracture resistance of Denture Base Acrylic. This experiment was designed to compare the transverse strength of samples of conventional and cross-linked acrylic with samples containing various proportions of one of two high modulus fibres. The stiffest and strongest specimens were those of the conventional acrylic and all the reinforced specimens were significantly weaker. The reason for this appears to be failure to achieve true adhesion between the fibre and the matrix resulting in the layers of fibre separating the matrix into layers of narrow cross-section. 相似文献
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Duane L. Sherrill MS Dr George D. Swanson PhD 《Journal of clinical monitoring and computing》1986,2(3):198-202
Anesthesiologists are concerned with the effect of various anesthetics on a patient's central nervous ventilatory control. The most widely accepted method of determining the effect of a drug is to compare carbon dioxide response curves (
e/PetCO2, where
e = minute ventilation [in L/min] andPetCO2 = end-tidal carbon dioxide [in mm Hg]) measured before and after administration of the drug. Additional information concerning neuromechanical control can be obtained by also including a measure of the airway occlusion pressure (generally measured 100 ms after occlusion, i.e., P100).To facilitate these measurements we have developed a portable, computer-controlled data acquisition system. It includes an Apple II+ computer and measures
e,PetCO2, and P100. Each subject rebreathes exhaled carbon dioxide through a two-way breathing valve attached to a 9-liter reservoir, which is initially filled with 5% carbon dioxide and balance oxygen. Exhaled carbon dioxide concentrations are measured with an infrared medical gas analyzer on samples taken through a catheter connected at the mouthpiece. The exhaled flow is measured with a pneumotachograph in conjunction with a differential pressure transducer, and P100 is determined with a Validyne MP45 pressure transducer. 相似文献
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Talakad G. Lohith Rong Xu Tetsuya Tsujikawa Cheryl L. Morse Kacey B. Anderson Robert L. Gladding Sami S. Zoghbi Masahiro Fujita Robert B. Innis Victor W. Pike 《Synapse (New York, N.Y.)》2014,68(12):613-623
The serotonin subtype‐4 (5‐HT4) receptor, which is known to be involved physiologically in learning and memory, and pathologically in Alzheimer's disease, anxiety, and other neuropsychiatric disorders—has few radioligands readily available for imaging in vivo. We have previously reported two novel 5‐HT4 receptor radioligands, namely [methoxy‐11C](1‐butylpiperidin‐4‐yl)methyl 4‐amino‐3‐methoxybenzoate; [11C]RX‐1), and the [18F]3‐fluoromethoxy analog ([18F]RX‐2), and in this study we evaluated them by PET in rhesus monkey. Brain scans were performed at baseline, receptor preblock or displacement conditions using SB 207710, a 5‐HT4 receptor antagonist, on the same day for [11C]RX‐1 and on different days for [18F]RX‐2. Specific‐to‐nondisplaceable ratio (BPND) was measured with the simplified reference tissue model from all baseline scans. To determine specific binding, total distribution volume (VT) was also measured in some monkeys by radiometabolite‐corrected arterial input function after ex vivo inhibition of esterases from baseline and blocked scans. Both radioligands showed moderate to high peak brain uptake of radioactivity (2–6 SUV). Regional BPND values were in the rank order of known 5‐HT4 receptor distribution with a trend for higher BPND values from [18F]RX‐2. One‐tissue compartmental model provided good fits with well identified VT values for both radioligands. In the highest 5‐HT4 receptor density region, striatum, 50–60% of total binding was specific. The VT in receptor‐poor cerebellum reached stable values by about 60 min for both radioligands indicating little influence of radiometabolites on brain signal. In conclusion, both [11C]RX‐1 and [18F]RX‐2 showed positive attributes for PET imaging of brain 5‐HT4 receptors, validating the radioligand design strategy. Synapse 68:613–623, 2014 . © 2014 Wiley Periodicals, Inc. 相似文献
36.
Thomas Rupp Fran?ois Esteve Pierre Bouzat Carsten Lundby Stéphane Perrey Patrick Levy Paul Robach Samuel Verges 《Journal of cerebral blood flow and metabolism》2014,34(1):52-60
This study investigated the changes in cerebral near-infrared spectroscopy (NIRS) signals, cerebrovascular and ventilatory responses to hypoxia and CO2 during altitude exposure. At sea level (SL), after 24 hours and 5 days at 4,350 m, 11 healthy subjects were exposed to normoxia, isocapnic hypoxia, hypercapnia, and hypocapnia. The following parameters were measured: prefrontal tissue oxygenation index (TOI), oxy- (HbO2), deoxy- and total hemoglobin (HbTot) concentrations with NIRS, blood velocity in the middle cerebral artery (MCAv) with transcranial Doppler and ventilation. Smaller prefrontal deoxygenation and larger ΔHbTot in response to hypoxia were observed at altitude compared with SL (day 5: ΔHbO2−0.6±1.1 versus −1.8±1.3 μmol/cmper mm Hg and ΔHbTot 1.4±1.3 versus 0.7±1.1 μmol/cm per mm Hg). The hypoxic MCAv and ventilatory responses were enhanced at altitude. Prefrontal oxygenation increased less in response to hypercapnia at altitude compared with SL (day 5: ΔTOI 0.3±0.2 versus 0.5±0.3% mm Hg). The hypercapnic MCAv and ventilatory responses were decreased and increased, respectively, at altitude. Hemodynamic responses to hypocapnia did not change at altitude. Short-term altitude exposure improves cerebral oxygenation in response to hypoxia but decreases it during hypercapnia. Although these changes may be relevant for conditions such as exercise or sleep at altitude, they were not associated with symptoms of acute mountain sickness. 相似文献
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