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11.
BACKGROUND: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. METHODS: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg.kg-1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg.kg-1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg.kg-1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. RESULTS: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). CONCLUSION: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.  相似文献   
12.
A Fast Search Algorithm for a Large Fuzzy Database   总被引:1,自引:0,他引:1  
In this paper, we propose a fast search algorithm for a large fuzzy database that stores iris codes or data with a similar binary structure. The fuzzy nature of iris codes and their high dimensionality render many modern search algorithms, mainly relying on sorting and hashing, inadequate. The algorithm that is used in all current public deployments of iris recognition is based on a brute force exhaustive search through a database of iris codes, looking for a match that is close enough. Our new technique, Beacon Guided Search (BGS), tackles this problem by dispersing a multitude of ldquobeaconsrdquo in the search space. Despite random bit errors, iris codes from the same eye are more likely to collide with the same beacons than those from different eyes. By counting the number of collisions, BGS shrinks the search range dramatically with a negligible loss of precision. We evaluate this technique using 632,500 iris codes enrolled in the United Arab Emirates (UAE) border control system, showing a substantial improvement in search speed with a negligible loss of accuracy. In addition, we demonstrate that the empirical results match theoretical predictions.  相似文献   
13.
This paper describes the Si-doping of GaAs that was grown using the AsCl3:H2:GaAs, Ga Chemical vapor deposition process. The doping sources were AsCl3:SiCl4 liquid solutions which proved to be highly reproducible for Si doping within the range, 1×1O16 to 2×1019 cm?3. Incorporation of Si into the GaAs apparently occurs under near equilibrium conditions. This point is considered in detail and the consequences experimentally utilized to grow n, n+ bilayers using a single AsCl3:SiCl4 doping solution. Si impurity profiles based upon differential capacitance and SIMS data are presented. These can be very abrupt for n, n+ structures with order of magnitude changes occurring within 500 Å. For the 1×1016 to 8×l018 cm?3 doped samples the mobilities at 78 and 298°K are comparable to the higher values reported for GaAs thin films grown by CVD. Power FET devices made from this material have demonstrated an output density of 0.86 watts/mm at 10 GHz.  相似文献   
14.
By using the arterial and venous phases of an anterior cerebral perfusion study, which showed downward displacement of the sagittal sinus, and the finding of a "rim" on the delayed scans, the specific diagnosis of epidural hematoma was established.  相似文献   
15.
We use low pressure MOVPE to grow indium antimonide films on groups of eight 3 inch GaAs wafers per run. The films are used for the production of magnetoresistive position sensors for the car industry. To meet the narrow specifications for automotive components, the standard deviation of the sheet resistivity, and the thickness of the films have been reduced below 1.5%. This uniformity is the result of an optimization process encompassing the determination of the best susceptor temperature and the optimum flow. The gas velocity was found to have a large impact on the uniformity of the layers. Rotation of the wafers and the use of an optimum gas velocity results in extremely uniform layers.  相似文献   
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OBJECTIVE: To evaluate the clinical/research utility of the low blood glucose index (LBGI), a measure of the risk of severe hypoglycemia (SH), based on self-monitoring of blood glucose (SMBG). RESEARCH DESIGN AND METHODS: There were 96 adults with IDDM (mean age 35+/-8 years, duration of diabetes 16+/-10 years, HbA1 8.6+/-1.8%), 43 of whom had a recent history of SH (53 did not), who used memory meters for 135+/-53 SMBG readings over a month, and then for the next 6 months recorded occurrence of SH. The SMBG data were mathematically transformed, and an LBGI was computed for each patient. RESULTS: The two patient groups did not differ with respect to HbA1, insulin units per day, average blood glucose (BG) and BG variability. Patients with history of SH demonstrated a higher LBGI (P < 0.0005) and a trend to be older with longer diabetes duration. Analysis of odds for future SH classified patients into low- (LBGI <2.5), moderate- (LBGI 2.5-5), and high- (LBGI >5) risk groups. Over the following 6 months low-, moderate-, and high-risk patients reported 0.4, 2.3, and 5.2 SH episodes, respectively (P = 0.001). The frequency of future SH was predicted by the LBGI and history of SH (R2 = 40%), while HbA1, age, duration of diabetes, and BG variability were not significant predictors. CONCLUSIONS: LBGI provides an accurate assessment of risk of SH. In the traditional relationship history of SH-to-future SH, LBGI may be the missing link that reflects present risk. Because it is based on SMBG records automatically stored by many reflectance meters, the LBGI is an effective and clinically useful on-line indicator for SH risk.  相似文献   
20.
We have analyzed the T-cell receptor (TCR) V beta repertoire using polymerase chain reaction (PCR) in a cohort of eight patients receiving allogeneic bone marrow transplantation (BMT) from related and unrelated donors at the City of Hope. Results of PCR studies from graft-versus-host disease (GVHD) skin lesions show a bias in the usage of TCR V beta families, whereas examination of peripheral blood (PB) withdrawn at the same time did not reveal a similar phenomenon. In one such family, TCR V beta 2 is predominantly expressed in 7 of 7 biopsy specimens examined. V beta 2 TCR expression from these patients was analyzed more extensively using a combination of individual TCR gene cloning, followed by sequence analysis. We found evidence of oligoclonal expansion of single V beta 2-bearing TCRs in GVHD lesions, and in the PB of some patients after diagnosis of GVHD. In contrast, GVHD-negative biopsy samples showed no evidence for clonotypic TCR amplification. Sequence-specific TCR CDR3 region probes were derived from analysis of the predominant expressed TCR in GVHD lesions, and used to probe Southern blots of amplified V beta 2 TCR mRNA from PB and tissue from BMT recipients and their respective donors. In most cases the probes are highly specific in detecting TCR expression from GVHD lesions alone, although in several instances expression could be detected in PB after GVHD diagnosis. These data provide supporting evidence for the hypothesis that acute GVHD is associated with expansion of T-cell clones expressing antigen-specific TCRs that may contribute to the disease pathology.  相似文献   
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