Micro pixel chambers (μ-PIC) with resistive cathodes have been developed as particle tracking/imaging detectors in high-rate high ionizing particle (HIP) environments. A main target of their ...development is as a forward muon detector in the ATLAS phase-2 upgrade. The cathode is made from DLC (diamond-like carbon) thin foil by the liftoff method. Using the resistive cathodes, the discharge (spark) probability within the HIP environment was reduced (10-1000 times) and two-dimensional readouts for the incident particles are available using a 400-micron pitch separated pixel array. We measured the tracking performances for the charged particles using a 140 GeV muon beam in CERN's H4 beam line and also measured the imaging properties of 8 keV X-rays. Two-dimensional fine position resolutions (< 100 micron) were obtained. These results show that the resistive μ-PIC is one of strong candidate for forthcoming high-rate particle experiments.
Under the scheme of the Kyoto Protocol, there are plans for the efficient reduction of carbon dioxide emissions. In the electric power sector, nuclear power generation, which emits no carbon dioxide ...in the process of generating electricity, has come under scrutiny. However, this energy produces a new environmental issue: the disposal of radioactive waste. First, we derive shadow prices of carbon dioxide and low-level waste as marginal abatement costs in the case of the electric power sector in Japan, employing a directional output distance function. It is found that the shadow prices are US$39 per tonne for carbon dioxide and US$1531 per liter for low-level waste. Secondly, we calculate the indirect Morishima elasticity between carbon dioxide and low-level waste in order to identify their substitutability, and it is found that the substitution of low-level waste for carbon dioxide is easier than the reverse. This result suggests that, with the amount of generated electricity fixed, carbon dioxide can be substituted more easily by low-level waste when the relative price of carbon dioxide increases, for example, as a result of implementation of a carbon dioxide tax or an emissions trading system.
Background. Radical resection of gliomas can increase patient’ s survival. There is known concern, however, that aggressive tumour removal can result in neurological morbidity. The objective of the ...present study was to evaluate the usefulness of low magnetic field strength (0.3 Tesla) open intraoperative magnetic resonance imaging (iMRI) for complete resection of glioma with emphasis on functional outcome.
Methods. From 2000 to 2004, 96 patients with intracranial gliomas underwent tumour resection with the use of iMRI in Tokyo Women ’s Medical University. There were 50 men and 46 women; mean age was 39 years. Tumour volume varied from 1.2 ml to 198 ml (median: 36.5 mL). Resection rate and postoperative neurological status were compared between control group (46 cases, operated on during the initial period after installation of iMRI), and study group (50 most recent cases, in whom surgery was done using established treatment algorithm and improved image quality).
Findings. Overall, mean resection rate was 93%, and medial residual tumour volume was 0.17 ml. Total tumour removal was achieved in 44 cases (46%). Compared to control group, resection rate in the study group was significantly higher (91% vs. 95%; P < 0.05), whereas residual tumour volume was significantly smaller (1.7 mL vs. 0.025 mL; P < 0.001). Nine patients in the control group (20%) and 24 in the study group (48%) experienced temporary postoperative neurological deterioration (P < 0.01), however, the rate of permanent morbidity evaluated 3 months after surgery did not differ significantly between the groups investigated (13% vs. 14%).
Conclusions. Use of iMRI during surgery for intracranial gliomas permits to attain aggressive tumour resection with good functional outcome. Nevertheless, surgical experience with the iMRI system, establishment of treatment algorithm, and improvement of image quality are of paramount importance for optimal results.
Most cases with chronic subdural hematoma (CSDH) are treated by simple irrigation and drainage, then more than eighty percent of them result in good recovery. But we sometimes encounter intractable ...cases with hematoma re-collection, which is considered of repeated bleeding from macrocapillary in the hematoma capsule. Embolization of the middle meningeal artery (MMA) is considered to be useful to eliminate the blood supply to this structure. The authors experienced seven cases of intractable CSDH treated by MMA embolization and no recurrence took place in all cases for up to 15 months. Endovascular treatment may be a good alternative modality for recurrent CSDH.
This paper describes a variable supply-voltage (VS) scheme. From an external supply, the VS scheme automatically generates minimum internal supply voltages by feedback control of a buck converter, a ...speed detector, and a timing controller so that they meet the demand on its operation frequency. A 32-b RISC core processor is developed in a 0.4-/spl mu/m CMOS technology which optimally controls the internal supple voltages with the VS scheme and the threshold voltages through substrate bias control. Performance in MIPS/W is improved by a factor of more than two compared with its conventional CMOS design.
Dural arteriovenous fistula (d-AVF) is relatively rare. Some cases of atypical locations are often difficult to distinguish from other vascular disorders or tumors because those d-AVFs show various ...onsets, such as subcortical bleeding and venous infarctions. We encountered two cases of d-AVF with severe brain edema that took adequate time to distinguish from brain tumors. A 68-year-old man visited his local physician complaining of dizziness. He was diagnosed with a cerebral infarction due to the presence of an abnormal cerebellar signal on magnetic resonance imaging (MRI) and was treated by drip infusion. However, he did not recover and was admitted to our hospital with suspicion of a brain tumor. A 75-year-old woman with an onset of progressive dementia and gait disturbance showed severe edema of the right-front temporal lobe on MRI. Both these cases were examined by single photon emission computed tomography or positron emission tomography and were scheduled for craniotomy and biopsy based on the diagnosis of brain tumor. We performed pre-operative angiography and found d-AVFs. We embolized the d-AVFs with liquid material and both patients recovered well.
Brain edema from d-AVF or a tumor can be distinguished by carefully reading the MRI with findings such as the distribution of the edemas, differences on diffusion-weighted images, and contrast-enhanced images. Therefore, it is important to provide initial accurate diagnoses to prevent patient mistrust and irreversible disease conditions.
— Aims: The influence of alcohol on the brain serotonergic system has been studied for several decades with some discordant results. The effects of continuous and constant treatment with ethanol on ...the rates of serotonin 5-hydroxytryptamine (5-HT) synthesis in discrete regions of the rat brain were studied. Methods: 5-HT synthesis rates were measured using the α-14Cmethyl-l-tryptophan autoradiographic method. The rats in the experimental group were treated with 50% ethyl alcohol and those in the control group received distilled water. The fluid was delivered subcutaneously by implanted osmotic mini-pumps for 14 days at the rate of 5 μl/h or 0.12 ml/day (0.06 ml of alcohol per day). Results: Chronic ethanol treatment, as delivered in the present experiment, induced a significant increase in the rate of 5-HT synthesis in descending serotonergic cell bodies (raphe pallidum, raphe obscurus, raphe magnus), nigrostriatal structures, the hippocampus and cortices. No significant changes were observed in the dorsal and median raphe nuclei or pineal body. The results suggest that there may be differences in the regulation of 5-HT synthesis in different brain structures after 14 days of continuous (subcutaneous) injection of 50% alcohol. Conclusions: Chronic ethanol treatments using osmotic mini-pumps induce non-uniform increases in 5-HT synthesis in the rat brain.
Non-traumatic subdural hemorrhage (SDH) caused by dural arteriovenous fistula (DAVF) is rare and is usually accompanied by intracerebral hemorrhage (ICH) and/or subarachnoid hemorrhage (SAH). This ...report describes a very rare case of DAVF that caused non-traumatic acute SDH without ICH or SAH, which subsequently progressed into chronic SDH.
The patient presented with a sudden-onset severe headache, and was diagnosed with acute SDH by computed tomography. Cerebral angiography showed a DAVF on the left convexity adjacent to the superior sagittal sinus (SSS). This DAVF drained to the SSS and to the pterygoid venous plexus via the left middle fossa without retrograde flow (Type I according to the Cognard classification). The SDH was thickest at the lower convexity, which suggested that the draining vein of the DAVF was responsible for the bleeding.
The SDH slowly progressed for two weeks. The DAVF was successfully treated with transarterial embolization using N-butyl 2-cyanoacrylate. The SDH was resolved via burr-hole drainage surgery.
This is the first reported case of DAVF that caused non-traumatic progression to SDH. As DAVF can be the cause of acute and chronic SDH, cerebral angiography is recommended for non-traumatic acute SDH as well as for intractable chronic SDH.
A 68-year-old male presented with a syncopal attack subsequent to acute myocardial infarction. His ultrasonographic and radiological examination revealed severe left internal carotid artery (ICA) ...stenosis and the presence of a persistent primitive hypoglossal artery (PPHA) immediately distal to the stenosis. The bilateral anterior and left middle cerebral arteries, and the vertebrobasilar system were opacified via the stenotic ICA. Carotid arterial stenting was selected as the treatment method because the lesion was high and a shunt placement during carotid endarterectomy was considered to be technically difficult. A self-expanding stent was successfully deployed with flow control, and the patient was discharged six days after surgery without any neurological deficit. There are sixteen reported cases including ours of PPHA associated with ICA stenosis presenting with ischemic attacks of the vertebrobasilar system. To the best of our knowledge, the current case is the first report of a cervical ICA stenosis with ipsilateral carotid-basilar anastomosis treated with carotid arterial stenting.
Endovascular treatments are minimally invasive and rarely cause complicating infections. Although cases complicated by device infections have been reported, we could not find any studies evaluating ...infections following neuroendovascular treatment in particular. Therefore, we assessed the frequency of sepsis and other associated risk factors.
From September 2006 to May 2008, we investigated 256 prospective neuroendovascular treatment cases at our facility. We examined the frequency of sepsis and other associated risk factors as well as organisms and the early detection tests such as various cultures and serodiagnoses.
The rate of sepsis due to complications was 8.6% in the aggregate and 5.7% in 193 procedures without a central venous catheter and hemodialysis. All sepsis cases were successfully treated with antibiotics. However, in 2 cases, the patients developed methicillin-resistant STAPHYLOCOCCUS AUREUS infections, which were intractable. The highest risk factors for sepsis were a large sheath size >7 F; OR =5.03; P =0.01; 95% confidence interval (CI) 1.29-19.47 and meningioma embolization (OR =13.25; P =0.04; 95% CI 1.07-163.56). The degree to which experienced staff (OR =0.09; P =0.05; 95% CI 0.09-0.97) affected the incidence of sepsis was less significant. Microorganisms were isolated from half the operating field, and the risk factor, in this case, depended on inexperienced surgical staff (OR =1.98; P =0.03; 95% CI 1.07-3.67). Although we were unable to find a means to predict sepsis, we presumed antibiotic prophylaxis would be useful.
The frequency of sepsis following neuroendovascular treatment is high. We should pay particular attention to the sterilization process and the operating field when undertaking neuroendovascular treatment that requires the use of a large-size sheath in patients with serious conditions.
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