The advantage of performing preoperative nerve blocks of the supraorbital and occipital nerves facilitates frame fixation and the perioperative management of patients in stereotactic neurosurgery, resulting in better patient handling with reduced intraoperative medication and less monitoring by anesthesia personnel.

In this study, the electrical characteristics and interface microstructures of GaAs-based n-n and p-n interface junctions prepared from direct wafer bonding have been systematically investigated through current-voltage measurements and transmission electron microscopy. It is found that a nearly continuous amorphous interface layer exists in all samples bonded at 400 °C. A drastic change in interface morphology caused by atomic rearrangement during high-temperature annealing at 600 °C leads to the formation of a locally perfect junction interface combined with an array of nanoscale, bubblelike amorphous regions. Each of them plays a different role in affecting carrier transports. The regions with local crystalline perfection can result in a considerable reduction of interface resistance for the majority carrier transport. However, the non-negligible interface resistance suggests that at interface boundary, there still exits a large number of interface states resulting from atomic imperfections, such as point defects and dangling bonds. On the other hand, the array of nanoscale, bubblelike regions is believed to provide a significant leakage path for minority carriers in p-n junctions. The p-n junction bonded at 400 °C exhibits an ideality factor of about 1.9 compared to 1.1 from an epitaxially grown p-n junction. After annealing at 600 °C, the increased leakage current along the bubblelike amorphous regions results in a deteriorating ideality factor from 1.9 to 2.5.

Sampling and analytical methods were developed to examine the input of various pesticides on noncultivated areas of the FAM (Research Network on Agroecosystems) Research Station Scheyern. Off-target drift from pesticide application on nearby cultivated land, as well as input due to long-range atmospheric transport, were measured. The wet deposition was determined by a cooled wet-only sampler. Bulk samplers and specially designed samplers with glass-fiber surface were used for total deposition measurements. Analysis of pesticides was carried out using liquid/liquid or solid-phase extraction and high performance liquid chromatography-UV (HPLC-UV) or gas chromatography-nitrogen/phosphorus-sensitive detector/MS (GC-NPD/MS) detection. Obtained results demonstrated that for several compounds, total deposition, i.e. the sum of wet and dry deposition, was marginally higher than wet deposition alone. In contrast, total deposition data of pesticides having been applied near the sampling site exceeded wet deposition values by orders of magnitude. In addition to direct drift, determined as droplets depositing near pesticide application areas, an indirect drift represented by particle-associated or gaseous transport was observed, both of which contributed considerably to total deposition. Therefore, to determine the input of pesticides to nontarget areas in the close vicinity of pesticide application, direct and indirect drift, and background deposition must be considered.

We compared psychomotor recovery after total intravenous anaesthesia (TIVA) with remifentanil/propofol and balanced anaesthesia (BAL) with etomidate/fentanyl/isoflurane in 40 patients, ASA I-III, aged > or =80 yr undergoing elective cataract surgery. Recovery times were recorded and psychomotor recovery was assessed according to simple reaction time, critical flicker fusion frequency (CFF) and short-term memory 30 min, 2 h and 1 day after surgery. Physical characteristics of patients in the two groups (19 in the TIVA group and 21 in the BAL group) were comparable. The TIVA group recovered significantly more quickly. Both groups showed a poorer psychomotor performance 30 min after surgery than at baseline assessment, but simple reaction time and short-term memory were close to baseline values 2 h after surgery. Only performance in the CFF test remained below baseline at this point. No deficits in psychomotor performance were noted on the first day after surgery. We conclude that there is only a minor deficit in psychomotor function in elderly patients 2 h after cataract surgery under general anaesthesia and that psychomotor function recovers completely by 24 h after surgery.

In this study we compared operating room (OR) efficiency of total intravenous anaesthesia (TIVA) with remifentanil and propofol and balanced anaesthesia (BAL) with fentanyl and isoflurane in cataract surgery using computersimulation. We simulated patient flow for one OR and for three ORs. Time intervals of patient flow were randomly generated from the results of a prospective, randomized trial. Both for one and for three ORs, the postanaesthesia care unit (PACU) finished earlier and one additional case per OR and per day could be performed when TIVA was used for the procedures. Overtime in the PACU was less after TIVA. With a workload of 13 or 15 operations per day in three ORs, monitoring equipment for an additional patient in the PACU was required when BAL was used. TIVA with remifentanil and propofol was associated with more OR efficiency than balanced anaesthesia with fentanyl and isoflurane when given for cataract surgery.

Zusammenfassung Die total intravenöse Anästhesie (TIVA) mit Remifentanil und Propofol und die balancierte Anästhesie (BAL) mit Fentanyl und Isofluran sollten mittels Computersimulation hinsichtlich ihrer Effizienz im perioperativen Ablauf bei Katarakteingriffen verglichen werden. Für beide Anästhesieverfahren wurde der Patientendurchfluss für OP-Bereiche mit einem bzw. 3 Operationssälen durch den Operationstrakt simuliert. Hierzu wurden nach dem Zufallsprinzip Werte des zeitlichen perioperativen Ablaufs, die in einer prospektiven, randomisierten Studie gewonnen worden waren, eingesetzt. Die TIVA ermöglichte sowohl für einen OP-Trakt mit einem Operationssaal als auch mit 3 Operationssälen eine frühere Schließung des Aufwachraums oder die Durchführung eines zusätzlichen Eingriffs pro Operationssaal pro Tag. Es fielen deutlich weniger Überstunden im Aufwachraum an als bei der BAL-Technik. Bei Durchführung von 13 oder 15 Eingriffen pro Tag in 3 Operationssälen wurde bei der BAL-Technik ein zusätzlicher Überwachungsplatz im Aufwachraum benötigt. Die TIVA-Technik ermöglicht in der Kataraktchirurgie eine effizientere Nutzung des OP-Bereichs verglichen mit der BAL-Technik.

Background and aim We evaluated the costs and benefits of total intravenous anaesthesia compared with a balanced anaesthesia regimen. Methods One-hundred and twenty-four patients undergoing cataract surgery were randomized to either a propofol/remifentanil or an isoflurane/fentanyl group. In the propofol/remifentanil group, both drugs were used for induction and maintenance of anaesthesia; in the isoflurane/fentanyl group, anaesthesia was induced with etomidate and fentanyl and maintained with isoflurane and fentanyl. All patients received mivacurium for muscle relaxation and the lungs were ventilated mechanically. The use of propofol and remifentanil resulted in a faster emergence and an overall savings per case of € 12.25 due to a reduction in personnel costs which outweighs the higher drug acquisition costs. Results In the propofol and remifentanil group, more patients were satisfied and would accept the same anaesthetic again. Conclusion We conclude that propofol and remifentanil is more cost-effective than isoflurane/fentanyl due to its better recovery profile, reduced total direct costs and higher patient satisfaction.

The DC current gain dependence of InGaP/GaAs heterojunction bipolar transistors (HBTs) on subcollector and etch-stop doping is examined. Samples of InGaP/GaAs HBTs having various combinations of subcollector doping and etch-stop doping are grown, and large area 60 /spl mu/m/spl times/60 (/spl mu/) HBTs are then fabricated for DC characterization. It is found that the DC current gain has a strong dependence on the doping concentration in the subcollector and the subcollector etch-stop. Maximum gain is achieved when the subcollector is doped at 6/spl sim/7/spl times/10/sup 18/ cm/sup -3/ while the subcollector etch-stop is doped either above 6/spl times/10/sup 18/ cm/sup -3/ (current gain/sheet resistance ratio, /spl beta//R/sub b/=0.435 at I/sub c/=1 mA) or below 3.5/spl times/10/sup 17/ cm/sup -3/ (/spl beta//R/sub b/=0.426/spl sim/0.438 at I/sub c/=1 mA). The data show that it is not necessary to heavily dope the subcollector etch-stop to reduce the conduction barrier and to obtain high current gain. The high current gain obtained with the low InGaP etch-stop doping concentration is attributed to the reduction of the effective energy barrier thickness due to band bending at the heterojunction between the InGaP etch-stop and the GaAs subcollector. These results show that the /spl beta//R/sub b/ of InGaP/GaAs HBTs can improve as much as 69% with the optimized doping concentration in subcollector and subcollector etch-stop.

The primary objective of the present experiment was to determine if lifelong supplementation with melatonin delayed reproductive senescence through decreased loss of ovarian primordial follicles. Holtzman rats were divided into three treatments on Day 10 after pupping (Day 0 = day of pupping). Treatment 1 pups had access to water, whereas Treatment 2 and 3 pups had access to water containing 10 μg/ml melatonin only at night (Treatment 2) or continuously (Treatment 3). Estrous cycles and weights of pups were monitored at selected times during the experiment; ovaries were removed for histology at 75 and 380 days of age. Vaginal opening in Treatment 2 was delayed (P < .01) compared with Treatments 1 and 3, but there was no difference (P > 0.05) among treatments in percentage of normal length estrous cycles from vaginal opening to 75 days of age. There were fewer (P < 0.001) abnormal-length estrous cycles from 180 to 380 days of age in Treatment 2 as compared with Treatments 1 or 3. There was no effect of treatment (P > 0.05) on number of primordial follicles. In conclusion, nighttime, but not continuous supplementation with melatonin, delayed puberty and reproductive senescence without any effect on number of primordial follicles.

PURPOSE:The new volatile anaesthetic agent desflurane has a significantly lower blood-gas partition coefficient (0.42) than isoflurane (1.4), suggesting excellent intraoperative control of anaesthesia and rapid emergence and recovery from anaesthesia. However, only limited experience is available in geriatric patients undergoing major abdominal surgery.METHODS:After approval by the local ethics committee and with written informed consent, 52 patients (> or = 65 years old, ASA class II or III) scheduled for major abdominal surgery were randomised to receive either desflurane (DES) or isoflurane (ISO) for maintenance of anaesthesia. After oral premedication with midazolam 3.75-7.5 mg, anaesthesia was induced with etomidate 0.2-0.3 mg/kg and fentanyl 3 micrograms/kg. Vecuronium 0.1 mg/kg provided muscle relaxation for endotracheal intubation. All patients were mechanically ventilated to maintain normocapnia. For maintenance of anaesthesia, DES or ISO was administered in 60% N2O and additional boluses of fentanyl and vecuronium were given as required. At the end of surgery, the neuromuscular blockade was reversed with neostigmine 0.02 mg/kg and DES or ISO was discontinued at the end of skin closure. Episodes of bradycardia and tachycardia and hypo- and hypertension, the time from the end of anaesthesia to extubation, opening eyes, squeezing hand, stating name and birthdate and to discharge from the recovery room were recorded. Until 360 minutes after the end of anaesthesia, the recovery of psychomotor functions was measured by means of simple reaction time tests, critical flicker fusion test, labyrinth test, ball bearing test, short and long-term memory test and digit symbol substitution test. The patient's well-being was documented with scores for pain, sedation and postoperative nausea and vomiting.RESULTS:Demographic data in both groups was similar (Tab. 1). Anaesthesia was significantly prolonged in the ISO group. No significant differences between groups were found for MAC hours and the total dose of fentanyl and vecuronium administered (Tab. 3). Intraoperative haemodynamics were comparable between both groups (Tab. 4). No episodes of increases in heart rate or blood pressure associated with rapid increases in DES concentration were seen. Early emergence parameters were faster in the DES group (Tab. 5). When compared to ISO, the overall test performance and testing ability was superior following DES. Psychomotor tests showed significantly better results up to 240 minutes after the end of DES anaesthesia (Tab. 7, Fig. 4). Comparing the postoperative well-being, there were mild advantages for DES (Tab. 6, Fig. 1, 2, 3). However, time to discharge of geriatric patients from the recovery room was significantly shorter in the DES group (median 171 vs. 215 min., p < 0.05).CONCLUSION:Using a balanced anaesthesia technique, we found desflurane as suitable as isoflurane for geriatric patients. Additionally, due to the fast emergence from anaesthesia, an improved cooperativity was found. In the DES group overall better postoperative psychomotor performance resulted in a shortening of discharge times from the recovery room. Hence, desflurane anaesthesia may be advantageous in geriatric patients.

The new volatile anaesthetic agent desflurane has a significantly lower blood-gas partition coefficient (0.42) than isoflurane (1.4), suggesting excellent intraoperative control of anaesthesia and rapid emergence and recovery from anaesthesia. However, only limited experience is available in geriatric patients undergoing major abdominal surgery.After approval by the local ethics committee and with written informed consent, 52 patients (> or = 65 years old, ASA class II or III) scheduled for major abdominal surgery were randomised to receive either desflurane (DES) or isoflurane (ISO) for maintenance of anaesthesia. After oral premedication with midazolam 3.75-7.5 mg, anaesthesia was induced with etomidate 0.2-0.3 mg/kg and fentanyl 3 micrograms/kg. Vecuronium 0.1 mg/kg provided muscle relaxation for endotracheal intubation. All patients were mechanically ventilated to maintain normocapnia. For maintenance of anaesthesia, DES or ISO was administered in 60% N2O and additional boluses of fentanyl and vecuronium were given as required. At the end of surgery, the neuromuscular blockade was reversed with neostigmine 0.02 mg/kg and DES or ISO was discontinued at the end of skin closure. Episodes of bradycardia and tachycardia and hypo- and hypertension, the time from the end of anaesthesia to extubation, opening eyes, squeezing hand, stating name and birthdate and to discharge from the recovery room were recorded. Until 360 minutes after the end of anaesthesia, the recovery of psychomotor functions was measured by means of simple reaction time tests, critical flicker fusion test, labyrinth test, ball bearing test, short and long-term memory test and digit symbol substitution test. The patient's well-being was documented with scores for pain, sedation and postoperative nausea and vomiting.Demographic data in both groups was similar (Tab. 1). Anaesthesia was significantly prolonged in the ISO group. No significant differences between groups were found for MAC hours and the total dose of fentanyl and vecuronium administered (Tab. 3). Intraoperative haemodynamics were comparable between both groups (Tab. 4). No episodes of increases in heart rate or blood pressure associated with rapid increases in DES concentration were seen. Early emergence parameters were faster in the DES group (Tab. 5). When compared to ISO, the overall test performance and testing ability was superior following DES. Psychomotor tests showed significantly better results up to 240 minutes after the end of DES anaesthesia (Tab. 7, Fig. 4). Comparing the postoperative well-being, there were mild advantages for DES (Tab. 6, Fig. 1, 2, 3). However, time to discharge of geriatric patients from the recovery room was significantly shorter in the DES group (median 171 vs. 215 min., p < 0.05).Using a balanced anaesthesia technique, we found desflurane as suitable as isoflurane for geriatric patients. Additionally, due to the fast emergence from anaesthesia, an improved cooperativity was found. In the DES group overall better postoperative psychomotor performance resulted in a shortening of discharge times from the recovery room. Hence, desflurane anaesthesia may be advantageous in geriatric patients.