Recovery Time Values Research Articles

Synthesis and gas sensing properties of high porosity n-type nickel ferrite thin film assisted by altering magnetic field

NiFe2O4 thin film with high porosity based gas sensors had been prepared and their microstructure and gas sensing property were investigated. The sensing layer, consisted of perpendicular overlapped NiFe2O4 chains which were induced by altering magnetic field to self-assemble, had high porosity. The phase character and porous microstructure were characterized by X-ray diffraction (XRD) and a polarizing optical microscopy. The gas sensing tests results indicated that the sensor presented a high sensitivity to NH3 at 150 °C, and was selective to NH3 below 200 °C. The large porosity microstructure should benefit the reaction between target gas and sensing material and the detection of low concentration gas at low working temperature. In repeatability tests, the response and recovery time values had only narrow fluctuations.

Assessment of susceptibility to pollution in littoral waters using the concept of recovery time

Susceptibility to pollution can be related to the flushing capacity of aquatic systems. Transport time scales constitute a useful tool for representing the water exchange and transport processes. A new transport time scale, recovery time, and a methodology to estimate it by means of numerical models is hereby developed. Recovery time, calculated in Gijon, Santander and Tarragona harbours, is significantly related to physical, chemical and biological water quality indicators. Susceptibility, assessed through recovery time values, provides spatial patterns of expected flushing capacity, being sensitive to physical and hydrodynamic characteristics. The developed method is appropriate to estimate recovery time and assess susceptibility against pollution in littoral waters having great potential to be applied to different disciplines. Recovery time could be used in littoral waters as a surrogate of water quality indicators, to establish efficient monitoring programs, to define and characterize modified water bodies or to improve the design of marine infrastructures.

Hydrogen sulfide removal performance of a bio-trickling filter employing Thiobacillus thiparus immobilized on polyurethane foam under various starvation regimes

In the present study a biotrickling filter (BTF) with countercurrent gas/liquid flow packed with open-pore polyurethane foam — as a carrier of Thiobacillus thioparus (DSMZ5368) — was subjected to various starvation regimes such as non-contaminant loading, idleness, and complete shutdown. During the starvation periods specific oxygen uptake rates of microorganisms (SOUR) on packing were monitored. The BTF was subjected to non-contaminant loading (up to 16 h), cyclic non-contaminant loading (for 4 days) and gas shut-off (up to 24 h), and it recovered to its pre-starvation removal efficiency within a 2 ∼ 3 h period after resuming normal operating conditions. The recovery time values obtained during the runs in which these starvation regimes were imposed could be indirectly correlated with the corresponding SOUR values suggesting that the recovery time after such starvation regimes are dependent on the degree to which the aerobic biological activity has been reduced as a result of the imposed starvation regime. In the case of the complete shutdown of the BTF, the recovery time increased substantially after 1 and 2 days of complete shutdown, and after 5 days of complete shutdown the pre-starvation removal efficiency was not achieved even after 12 days of normal operation.

Comparison of ketamine and propofol as maintenance agent for continuous intravenous infusion anaesthesia in water buffaloes

The present study was conducted to compare the anaesthetic effects of ketamine and propofol as maintenance agents for continuous intravenous infusion anaesthesia in buffaloes. Clinically healthy adult male buffaloes (6), 2 to 3 year-old and weighing 290 to 325 kg, were used for repeated trials in 2 groups using medetomidine (2.5µg/kg) and butorphanol (0.05 mg/kg) intravenously as preanaesthetics. Induction of anaesthesia was achieved with 5% thiopental sodium in both groups. Anaesthesia was maintained with continuous intravenous infusion of ketamine (1%) in group K and propofol (1%) in group P. The treatments were compared by clinicophysiological, cardiorespiratory and haemodynamic parameters. Excellent sedation, analgesia and muscular relaxation were observed in both groups. Depression of palpebral and corneal reflex was higher in group P than in group K. Downward rotation of eye ball for longer time was observed in group P than in K group. Required mean infusion rates of ketamine and propofol to maintain the adequate depth of anaesthesia in groups K and P were 0.16±0.01 mg/kg/min and 0.05±0.00 mg/kg/min, respectively. The values of recovery time, sternal recumbency time and standing time did not differ significantly between the groups. Difference in heart rate was not significant up to 60 min of anaesthesia but after 70 min onwards HR in group K was significantly higher compared to groups P. Respiratory rate in groups K remained significantly higher during the maintenance period than in group P. Decrease in rectal temperature was significantly higher in group P than in K group. Mean arterial pressure in groups K remained significantly lower than in group P. Central venous pressure did not differ significantly between the groups. Haemoglobin oxygen saturation (SpO2) in group P remained significantly higher than in group K. Our results indicated that maintaining anaesthesia via continuous infusion of ketamine and propofol in buffaloes is a feasible, effective, and safe anaesthetic technique for surgical procedures of at least up to 2 h duration. Maintaining anaesthesia with propofol produced some depressive effects on cardiopulmonary parameters that were comparable to those associated with anaesthesia maintained by ketamine.

Sinus nodal response to adenosine relates to the severity of sinus node dysfunction

It is unknown as to whether the result of adenosine testing for the diagnosis of sinus node dysfunction (SND) depends on the clinical presentation. We investigated whether syncope or presyncope are associated with a more pronounced sinus nodal inhibition by adenosine in SND. We studied 46 patients with SND, 33 with syncope or presyncope and 13 without such history. Controls were 30 subjects undergoing electrophysiological studies for supraventricular tachycardia or unexplained syncope. We calculated the corrected sinus node recovery time after intravenous adenosine 0.15 mg/kg (ADSNRT) as well as after atrial pacing (CSNRT). Corrected sinus node recovery time values >525 ms were considered abnormal. Corrected sinus node recovery time after adenosine injection was more prolonged in SND patients with syncope or presyncope as compared with those without such history [median: 4900 inter-quartile range (IQR): 920-8560 ms vs. median: 280 IQR: 5-908 ms; P< 0.005]. In SND patients with syncope or presyncope ADSNRT was more prolonged than CSNRT (median: 4900 IQR: 920-8560 ms vs. median: 680 IQR: 359-1650 ms, P< 0.01). In SND patients without syncope or presyncope no statistical difference was noted between ADSNRT and CSNRT (median: 280 IQR: 5-908 ms vs. median: 396 IQR: 270-600 ms, P = 0.80). The sensitivity of CSNRT for SND diagnosis was 57% and the specificity was 100%. A cut-off of 1029 ms for ADSRNT yields the same sensitivity with a specificity of 96.6%. In patients with SND syncope or presyncope relate to an exaggerated sinus nodal suppression by adenosine. Prolonged ADSNRT can diagnose cases with severe underlying SND where a more aggressive management strategy is probably warranted.

Extending the range of applicability of HTS cylinders in inductive superconducting faultcurrent limiters

Here, we study the behaviour of an inductive superconducting fault current limiter (SFCL)whose secondary is a bulk cylinder with an array of appropriately distributed weak zones.This design allows heat to be removed by conduction from the hot weak zones, whichabsorb the power dissipation, to the remaining colder parts of the cylinder. Our workhighlights the possibility of overcoming the limitations of high power SFCLs based on bulkcylinders, which present recovery time values well beyond the maximum value tolerated ina distribution line.

The Effect of Bispectral Index Monitoring on Anesthetic Use and Recovery in Long Duration Sevoflurane Anesthesia

Background: The bispectral index (BIS), a parameter derived from the electro-encephalography (EEG), has been shown to correlate with the sedative state of anesthetic agents. This study was designed to evaluate the effect of BIS monitoring on anesthetic use and recovery characteristics in long duration sevoflurane anesthesia. Methods: Forty adult patients who were scheduled for prolonged anesthesia (above 150 minutes) were randomly assigned to the control group (n = 20) or the BIS group (n = 20). In the control group, the anesthesiologists were blinded to the BIS values, and sevoflurane was administered according to standard clinical practice. In the BIS group, sevoflurane was titrated to maintain the BIS value between 45-60. Mean arterial pressure (MAP), heart rate (HR), end-tidal sevoflurane, BIS was monitored at intervals of 15 minutes. Time to response (), time to extubation (), time to reach 10 points of PAR score () and time to the discharge from postanesthetic care unit () were recorded from withdrawal of sevoflurane for recovery time. Results: -Sevoflurane was significantly lower in the BIS group than the control group. BIS and 95% SEF values were higher in the BIS group compared with the control group. All values of recovery time (, , , ) were significantly shorter in the BIS group than control group. In MAP and HR, there was no significant difference between the groups. Conclusions: BIS is considered a good index of proper use of sevoflurane. Decrease of total amount of sevoflurane, early emergence and early discharge from PACU are expected, so more safe and economic anesthesia may be possible in clinics.

Application of nonlinear and local modeling methods for 3D QSAR study of class I antiarrhythmics

Locally weighted regression and artificial neural networks were employed to find a quantitative relationship between recovery time and molecular structures for class I antiarrhythmics. Nonlinear and local models have been built between score vectors of columns of Comparative Molecular Field Analysis (CoMFA) as independent variables and recovery time values as dependent variables. Other method by applying cheaply computed descriptors invariant to roto-translation with artificial neural networks were also used. Predictive ability of the methods was tested by a separate set of compounds, and the performance of both procedures proved to be acceptable, and comparable to CoMFA. This study clearly demonstrates the need and ability of nonlinear algorithms in building of 3D QSARs. The methods presented here do not assume any particular functional form for developing quantitative models between molecular descriptors and biological activity.

ANESTHESIA CLINICAL PATHWAYS FOR SAME-DAY ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION DECREASE TIMES TO DISCHARGE HOME

S22 Understanding which activities add value to patient care will likely decrease costs generated by process variability. A useful indicator of the cost-effectiveness of an anesthetic in the ambulatory setting is the recovery time, or the time from OR exit to discharge from the facility. In studying this quality indicator, we developed anesthesia clinical pathways (CP) in conjunction with surgeons who routinely care for outpatients undergoing anterior cruciate ligament (ACL) reconstruction of the knee. We demonstrate that these CPs decrease the total time for phase I and phase II recovery, when compared with time data for historical controls who underwent non-standardized anesthesia and postoperative care plans. Methods: After IRB approval, we reviewed the medical records of consecutive outpatients undergoing ACL reconstruction from July 1995 to June 1997. Patients in academic year (AY) 1995-96 were not subjected to standardized anesthesia care. AY 1996-97 patients (in whom no contraindications existed) selected epidural anesthesia (EA), general anesthesia (GA), or GA with femoral nerve block (GFNB). EA consisted of lumbar epidural catheters placed preoperatively after sedation with fentanyl and midazolam, epidural dosing with lidocaine and fentanyl, and intraoperative sedation with propofol. Both GA and GFNB included induction with propofol and muscle relaxation with succinylcholine; maintenance with endotracheal desflurane, nitrous oxide, and oxygen; and opioid analgesia with fentanyl. Intraoperative fentanyl doses were decreased in the GFNB patients, who had femoral nerve blocks (with bupivacaine) placed preoperatively. All CP patients were given intraarticular morphine (10 mg) and bupivacaine (0.5%, 30cc) at the end of the surgical procedure. Patients at risk by history for postoperative nausea/vomiting (PONV) were given empiric droperidol and metoclopramide intraoperatively, and patients with refractory PONV were given a sequence of metoclopramide, droperidol, ondansetron, and perphenazine postoperatively before admission was considered. Duration of recovery data from these patients were compared with historical controls, who had a non-standardized intraoperative and postoperative anesthesia care plan. The only similarity between the historical controls and the CP patients was the intraarticular injection at the end of the procedure. Recovery time values were analyzed using one-way analysis of variance (ANOVA), with significant differences in pairwise comparisons determined by independent-sample t-tests. P < 0.05 was considered statistically significant. Results: Time data from 150 ACL anesthesia CP patients (31 CP-GA, 62 CP-EA, 57 CP-GFNB) and 122 historical (H) controls (26 regional, 96 general) were examined. Patients who were known in advance to be admitted postoperatively, who were admitted because of an extension of the surgical procedure, or who were admitted for intractable pain or PONV were excluded from this analysis. CP patients (207 +/- 20 min, mean +/- std. error of mean) were discharged home 35 minutes sooner than were historical controls (242 +/- 14 min, P = 0.008). No significant differences in discharge times were seen within the CPs. Discussion: For ACL reconstruction, the anesthesia process influenced recovery times. Whether anesthesia CP for other surgical procedures would benefit or adversely affect recovery times, and whether decreases in recovery times would create scheduling opportunities with respect to recovery nurse staffing, [1] requires further study.

Time‐domain numerical modelling of microwave non‐linear circuits

AbstractA numerical time‐domain modelling of non‐linear microwave circuits is presented. It is based on a numerical procedure allowing the solution of the integro‐differential equation driving the instantaneous electrical behaviour of a lumped‐element circuit while accounting for the semiconductor device by means of an accurate numerical macroscopic model. This modelling is firstly validated by studying the DC turn‐on and DC forward–reverse commutation of a PIN diode. The diode voltage and current waveform are qualitatively consistent with experimental ones, Moreover, the predicted recovery time values are found to be in good agreement with those issued from the classical analytical theory. Secondly, in order to illustrate the present capabilities of the model, the whole transient response of a back‐to‐back silicon PIN diode passive power limiter to a high‐input‐RF‐power pulse is described. It is demonstrated that in the present case of a 2 μm‐long PIN diode, the high‐input‐power steady‐state operation only relies on one diode. To our knowledge, it is the first time this kind of simulation is applied to a two‐diode circuit.

Postocclusive transcutaneous oximetry in followup assessment of tibial nonunion and healed tibia fractures.

Transcutaneous oximetry measurements were performed on 25 limbs in 25 patients with clinical and radiographic nonunion, and compared with data obtained from patients with healed tibia fractures and a control group of nonfractured extremities. A technique of "stress testing" vascular inflow patterns by temporary occlusion of arterial inflow was utilized to accentuate differences in perfusion not apparent at rest between normal limbs and those with inflow impairment. Changes in postocclusive hyperemic response were monitored by changes in transcutaneous oxygen detected by sensors placed over the dorsum of the foot, at the fracture site, over the anterior compartment, and at the chest. No statistically significant differences were found between the control group and the group of united tibia fractures. Analysis of results using the unpaired Student's t-test demonstrated statistically significant differences between the control and nonunion groups at each limb site tested (p less than 0.05). The prolonged oxygen recovery time values found in more than half the limbs with nonunion are consistent with the presence of impaired oxygenation following physiologic stress. The impairment of oxygenation appears to be on a perfusion basis and reflects the limited capacity of many limbs with tibial nonunion to respond to experimental ischemia with immediate compensatory hyperemia. This technique is a feasible method for serially assessing the regional oxygenation of a limb, and substantiates ischemia as a possible factor in the genesis of tibial nonunion.

Comparison of transcutaneous oximetry, vascular hemodynamic measurements, angiography, and clinical findings to predict the success of peripheral vascular reconstruction

The present study examined prospectively the prognostic value of preoperative clinical findings, angiography, and conventional vascular hemodynamic and transcutaneous oximetry measurements in a consecutive series of patients undergoing lower extremity vascular reconstruction. A total of 25 variables were independently evaluated in each limb. Follow-up at least 6 months after operation was carried out in all patients. The postocclusive transcutaneous oxygen recovery time was found to be the most accurate predictor of short-term femoropopliteal bypass graft success. Preoperative foot transcutaneous oxygen recovery time values were significantly worse in patients whose femoropopliteal bypass grafts failed than in those in whom the outcome was successful (p less than 0.03). Transcutaneous oxygen recovery time values were also valuable in patients who underwent aortofemoral bypass; patients with isolated aortoiliac disease had significantly better foot transcutaneous oxygen recovery time values than those with combined aortoiliac and femoropopliteal disease (p less than 0.05). Foot transcutaneous oxygen recovery time values were also found to correlate well with the severity of symptoms (p less than 0.01), as did ankle-brachial Doppler pressure indices. Although the other variables analyzed provided useful diagnostic information, none were as accurate as the postocclusive transcutaneous oxygen recovery time in predicting the outcome of peripheral vascular reconstruction. As a means of more accurately classifying patients with peripheral vascular disease, we recommend the complimentary use of clinical findings, angiography, and hemodynamic and transcutaneous oximetry measurements. Because transcutaneous oxygen tension reflects the balance between local oxygen supply and demand, it may help to better define risk factors preoperatively in physiologic terms.

Signal Processor Recovery Time Effects on Photon Counting Accuracy, Observed Counts, and True Events

The response time of the signal processor is examined from the standpoint of the trade-offs that can be made by the experimenter in defining the data accuracy in terms of the signal processor recovery time, observed counts, standard deviation, and required number of data scaler bits. Curves are shown which for different values of recovery time, the true event rate can be determined at an observed count rate. Other curves show the relationship between data scaler bit levels and resultant data accuracy at different standard deviations.