Temperature dependent control of the solubility of gallium nitride in supercritical ammonia using mixed mineralizer.

Using a mass-loss method, we investigated the solubility change of gallium nitride (GaN) in supercritical ammonia with mixed mineralizers [ammonium chloride (NH4Cl) + ammonium bromide (NH4Br) and NH4Cl + ammonium iodide (NH4I)]. The solubilities were measured over the temperature range 450-550 °C, at 100 MPa. The solubility increased with NH4Cl mole fraction at 450 °C and 100 MPa. The temperature dependence of the solubility curve was then measured at an equal mole ratio of the two mineralizers. The slope of the solubility-temperature relationship in the mixed mineralizer was between those of the individual mineralizers. These results show that the temperature dependence of the solubility of GaN can be controlled by the mineralizer mixture ratio. The results of the van't Hoff plot suggest that the solubility species were unchanged over the investigated temperature range. Our approach might pave the way to realizing large, high-quality GaN crystals for future gallium-nitride electronic devices, which are increasingly on demand in the information-based age.

Local elevation of the anti-inflammatory interleukin-10 in the pathogenesis of chronic subdural hematoma.

We investigated the relationship between inflammatory and anti-inflammatory cytokines in the pathogenesis of chronic subdural hematoma (CSDH) by measuring the plasma and subdural fluid levels of interleukin-6 (IL-6), interleukin-8 (IL-8), and interleukin-10 (IL-10). The levels of IL-6, IL-8 and IL-10 were measured in the subdural fluid obtained from 34 patients with CSDH, using the enzyme-linked immunosorbent assay. The patients were classified into a high IL-10 group and a low IL-10 group according to the level of IL-10 in their subdural fluid samples. The subdural fluid levels of IL-6 and IL-8 were significantly higher in the high IL-10 group than in the low IL-10 group (P<0.05). A tendency for the patients in the low IL-10 group to show the separated or layer type of pattern on the CT scans was noted.

Recovery process of immediate prolonged posttraumatic coma following severe head injury without mass lesions.

The recovery process of immediate posttraumatic coma was investigated in 24 patients with severe head injury. The correlation between poor outcome in the recovery process and magnetic resonance (MR) imaging findings was analyzed. MR imaging was performed within the first 7 days for all patients. The recovery process was classified into phase 1 for recovery to moderately disabled and phase 2 to good recovery (GR) according to the Glasgow Outcome Scale. The median of phase 1 was 21.0 days. Four patients did not recover to GR and had poor outcome. Twenty patients recovered to GR. Thirteen patients had short phase 2 of under 10 days and seven patients had long phase 2 of over 60 days. All patients had abnormal lesions on MR imaging considered to be diffuse axonal injury. The number of lesions ranged from two to 10, with a mean of five. Lesions in the dorsal upper brainstem were significantly associated with poor outcome (p < 0.05). The combination of focal lesions in the callosal splenium and dorsal upper brainstem was most common in patients with poor outcome. Patients with long phase 2 had significantly more lesions than patients with short phase 2.

Effects of EC-IC bypass surgery on cognitive impairment in patients with hemodynamic cerebral ischemia.

BACKGROUND: Chronic ischemia because of internal carotid artery (ICA) occlusive disease may result in dementia. The goal of this study was to assess cognitive impairment in symptomatic patients with hemodynamic cerebral ischemia and determine the efficacy of extracranial-intracranial (EC-IC) bypass in restoring neuropsychologic integrity. METHODS: Twenty-five patients were defined by clinical and neuroradiological criteria as suffering from hemodynamic cerebral ischemia because of unilateral ICA or middle cerebral artery occlusion. Subjects underwent assessment of cerebral blood flow and metabolism using positron emission tomography (PET) before and after bypass surgery. To provide data regarding cognition, changes in the Japanese Wechsler Adult Intelligence Scale Revised (WAIS-R) were recorded. RESULTS: Preoperative study of patients revealed significant impairment in cerebral blood flow and metabolism as well as reduced WAIS-R score. Among the factors considered, only elevated regional oxygen extraction fraction and reduced regional cerebral metabolic rates of oxygen were significantly associated with preoperative cognitive impairment (p = 0.0032 and p = 0.0255, respectively; logistic regression analysis). After bypass surgery, cerebral blood flow and metabolism improved significantly, and the WAIS-R score increased. CONCLUSIONS: Symptomatic patients with hemodynamic cerebral ischemia displayed impaired cognition that was partially alleviated with EC-IC bypass surgery.

[A case of the development of cavum vergae after head trauma].

We report a case of the development of cavum septi pellucidi and cavum Vergae after head trauma in a 29-year-old female patient. After the accident, cavum septi pellucidi and cavum Vergae gradually expanded. Using magnetic resonance imaging, we followed up the patient for 33 months after the head trauma. Preoperatively, metrizamide CT cisternography was performed in order to investigate CSF flow between the cavum septi pellucidi/cavum Vergae and the subarachnoid space. Using neuroendoscopy, we succeeded in opening the wall of the cavum septi pellucidi via anterior horn of the right lateral ventricle. Cystography was performed during the operation. The volume of the cavum septi pellucidi/cavum Vergae decreased remarkably. In this case, our CSF flow studies revealed that CSF flowed into the posterior part of the cavum Vergae from the third ventricle and did not flow backward to the third ventricle. Therefore, we considered that the development of cavum septi pellucidi/cavum Vergae was related to a one-way valve mechanism between the posterior part of the cavum Vergae and the third ventricle.