Abstract A design concept and experimental results are reported on a distributed amplifier with a flat gain characteristic. To obtain a broadband characteristic, the distributed amplifier is designed in such a way that the input power to each FET is as equal as possible. The obtained performances at 2 to 18 GHz are such that the gain is 7 ± 0.5 dB, the noise figure is less than 5.8 dB, and the VSWR is less than 2. In this amplifier, a self‐bias circuit is installed at the source electrode of each FET so that it can be operated with a single power supply.
At present, no satisfactory reports on the monitoring of cerebral function to predict functional outcomes after brain damage such as traumatic brain injury (TBI) and stroke. The middle latency auditory-evoked potential index (MLAEPi) monitor (aepEX plus®, Audiomex, UK) is a mobile MLAEP monitor measuring the degree of consciousness that is represented by numerical values. Hence, we hypothesized that MLAEPi predicts neurological outcome after emergency craniotomy among patients with disturbance of consciousness (DOC), which was caused by brain damage. The afore-mentioned patients who underwent emergency craniotomy within 12 h of brain damage and were subsequently monitored using MLAEPi were enrolled in this study. DOC was defined as an initial Glasgow Coma Scale score < 8. MLAEPi was measured for 14 days after craniotomy. Neurological outcome was evaluated before discharge using a cerebral performance category (CPC) score and classified into three groups: favorable outcome group for a CPC score of 1 or 2, unfavorable outcome group for a score of 3 or 4, and brain dead (BD) group for a score of 5. Thirty-two patients were included in this study (17 with TBIs and 15 with acute stroke). Regarding outcome, 10 patients had a favorable outcome, 15 had an unfavorable outcome, and 7 were pronounced BD. MLAEPi was observed to be significantly higher on day 5 than that observed immediately after craniotomy in cases of favorable or unfavorable outcome (63 ± 3.5 vs. 36 ± 2.5 in favorable outcome; 63 ± 3.5 vs. 34 ± 1.8 in unfavorable outcome). MLAEPi was significantly lower in BD patients than in those with a favorable or unfavorable outcome on day 3 (24 ± 4.2 in BD vs. 52 ± 5.2 and 45 ± 2.7 in favorable and unfavorable outcome, respectively) and after day 4. MLAEPi was significantly higher in patients with a favorable outcome than in those with a favorable or unfavorable outcome after day 6 (68 ± 2.3 in favorable outcome vs. 48 ± 2.3 in unfavorable outcome). We believe that MLAEPi satisfactorily denotes cerebral function and predicts outcomes after emergency craniotomy in patients with DOC, which was caused by acute brain damage.
The strategy of this study was to improve the electronic spin resonance (ESR) application used to detect free radical-induced oxidative stress in animal models. We have developed an in vivo ESR imaging system with high-quality ESR-computed tomography (CT) images by using a nitroxyl spin probe—BBB-permeable, 3-methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-yloxy (MC-PROXYL)—in living small animals. We first measured the distribution of MC-PROXYL in the head region of a living mouse by using ESR-CT imaging after treatment with MC-PROXYL. In the ESR-CT experiments, it was clearly observed that MC-PROXYL was well distributed in the brain of head region of a living mouse. The ESR-CT images taken after treatment with MC-PROXYL demonstrate that the decay of MC-PROXYL in the isolated brain of a spontaneously hypertensive rat (SHR) was more rapid than that in a Wister Kyoto rat. ESR-CT analysis revealed that the region of rapid decay might be located in the cerebral cortex of the isolated brain of an SHR. These results suggest that the present study of ESR-CT imaging would be a useful tool for monitoring and detecting the locations of oxidative stress in the brains of rodent animal models.
The purpose of this study is to describe a new technique for en bloc temporal bone resection using a diamond threadwire saw (T-saw) as an alternative to cutting the temporal bone with an osteotome. This technique has been performed in 10 patients with external auditory canal and middle ear cancers without any injury to the internal carotid artery or jugular vein. The authors conclude that the use of a diamond threadwire saw after transposing the internal carotid artery anteriorly is a safe, simple, and reliable technique for en bloc temporal bone resection.
