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排序方式: 共有1413条查询结果,搜索用时 15 毫秒
71.
NN Pribylova AI Tret''iakov AF Neronov MN Moskalev AI Kaminin NL Katyshev SI Portniagina 《Canadian Metallurgical Quarterly》1997,75(1):38-40
A correct access opening is the key to endodontics. An adequate anatomical access preparation maximizes cleaning, shaping, and obturation. The major objectives of access preparation are straight line access to the apical area, conservation of tooth structure, and unroofing of the pulp chamber. The safe-ended diamond bur technique provides an efficient and rapid means to obtain the objective of access preparation in posterior teeth. 相似文献
72.
K Nabeshima T Nakagawa AF Straight A Murray Y Chikashige YM Yamashita Y Hiraoka M Yanagida 《Canadian Metallurgical Quarterly》1998,9(11):3211-3225
In higher eukaryotic cells, the spindle forms along with chromosome condensation in mitotic prophase. In metaphase, chromosomes are aligned on the spindle with sister kinetochores facing toward the opposite poles. In anaphase A, sister chromatids separate from each other without spindle extension, whereas spindle elongation takes place during anaphase B. We have critically examined whether such mitotic stages also occur in a lower eukaryote, Schizosaccharomyces pombe. Using the green fluorescent protein tagging technique, early mitotic to late anaphase events were observed in living fission yeast cells. S. pombe has three phases in spindle dynamics, spindle formation (phase 1), constant spindle length (phase 2), and spindle extension (phase 3). Sister centromere separation (anaphase A) rapidly occurred at the end of phase 2. The centromere showed dynamic movements throughout phase 2 as it moved back and forth and was transiently split in two before its separation, suggesting that the centromere was positioned in a bioriented manner toward the poles at metaphase. Microtubule-associating Dis1 was required for the occurrence of constant spindle length and centromere movement in phase 2. Normal transition from phase 2 to 3 needed DNA topoisomerase II and Cut1 but not Cut14. The duration of each phase was highly dependent on temperature. 相似文献
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M Kaartinen GM Griffiths AF Markham C Milstein 《Canadian Metallurgical Quarterly》1983,304(5924):320-324
Light and heavy chain mRNAs of 15 anti-oxazolone antibodies were sequenced directly using synthetic primers. Hybridomas obtained 7 days after primary immunization show that they are of restricted heterogeneity. The majority expressed a single sequence with minor differences concentrated in the D region and joining boundaries D--JH and V kappa--J kappa. 相似文献
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OBJECTIVE: To measure the actual concentrations of dopamine, dobutamine, and epinephrine in infusates prepared for patients, and to compare these concentrations with those of the dopamine HCl, dobutamine, and epinephrine HCl infusates that had been prescribed to evaluate drug preparation accuracy. DESIGN: Prospective, unblind study. SETTING: Pediatric intensive care unit in a tertiary-care teaching hospital. PARTICIPANTS: All dopamine, dobutamine, and epinephrine infusions ordered for patients during the 2-month study period were eligible for inclusion in the study. MEASUREMENTS: Daily samples of dopamine, dobutamine, and epinephrine infusates that were prepared for 41 pediatric patients were obtained; the infusate catecholamine concentration was measured by HPLC and compared with the ordered concentration. The concentration than was multiplied by the rate of infusion to determine the catecholamine dose. MAIN RESULTS: There were significant differences between the measured doses of dopamine, dobutamine, and epinephrine and the dopamine HCl, dobutamine, and epinephrine HCl doses (p = 0.0001, p = 0.039, and p = 0.0009, respectively) that had been ordered because of preparation inaccuracies. Failure to account for the HCl salt in the stock drug accounted for some, but not all, of the inaccuracy of the dopamine HCl and epinephrine HCl infusates. There was a wide interday variability in the measured catecholamine dosage in patients receiving the same dose for 3 days or more. CONCLUSIONS: There are daily fluctuations in the preparation of dopamine, dobutamine, and epinephrine infusates that could alter the amount of drug actually delivered to critically ill patients and potentially contribute to their hemodynamic instability. 相似文献
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ML Nochomovitz AF Dimarco JT Mortimer NS Cherniack 《Canadian Metallurgical Quarterly》1983,127(3):325-329
We studied in 10 supine anesthetized dogs diaphragm contraction produced by electrical activation with intramuscular electrodes surgically implanted in the ventral surface of the diaphragm and compared this with activation of the ipsilateral phrenic nerve (C5, 6, and 7) before it entered the thorax. Repetitive 40-Hz pulse trains with supramaximal current stimulus were used after hyperventilation of the animals to apnea. A single intramuscular electrode within 1 to 2 cm of the site of phrenic nerve entry into the diaphragm produced a mean transdiaphragmatic pressure of 12.0 cm H2O +/- 0.97 SE and mean tidal volume of 0.27 L +/- 0.04 SE. Mean values observed with phrenic nerve stimulation were not statistically different, and both electrode systems produced equivalent outward abdominal motion and upper rib cage paradox, as monitored by inductive plethysmography. There was no difference in gas exchange during stimulation with a single hemidiaphragm electrode and mechanical ventilation compared at the same tidal volume and respiratory rate. Blockade of neuromuscular transmission with curare eliminated intramuscular and phrenic nerve stimulation proportionately, suggesting that activation of the diaphragm is dependent in both cases on the phrenic nerve. This technique does not entail manipulation of the phrenic nerve and may have clinical application as an alternative technique for diaphragm pacing. 相似文献