Accumulation and depletion layer thicknesses in organic field effect transistors

We present a simple but powerful method to determine the thicknesses of the accumulation and depletion layers and the distribution curve of injected carriers in organic field effect transistors. The conductivity of organic semiconductors in thin film transistors was measured in-situ and continuously with a bottom contact configuration, as a function of film thickness at various gate voltages. Using this method, the thicknesses of the accumulation and depletion layers of pentacene were determined to be 0.9 nm (VG=-15 V) and 5 nm (VG=15 V).Comment: 3 pages, 4 figures, Jap. J. Appl. Phys. in pres

Electric field induced charge injection or exhaustion in organic thin film transistor

The conductivity of organic semiconductors is measured {\it in-situ} and continuously with a bottom contact configuration, as a function of film thickness at various gate voltages. The depletion layer thickness can be directly determined as a shift of the threshold thickness at which electric current began to flow. The {\it in-situ} and continuous measurement can also determine qualitatively the accumulation layer thickness together with the distribution function of injected carriers. The accumulation layer thickness is a few mono layers, and it does not depend on gate voltages, rather depends on the chemical species.Comment: 4 figures, to be published in Phys. Rev.

Gelatin hydrogel nonwoven fabrics of a cell culture scaffold to formulate 3-dimensional cell constructs

The objective of this study is to evaluate the possibility of gelatin hydrogel nonwoven fabrics (GHNF) of a cell culture scaffold to formulate 3-dimensional (3D) cell construct. The thickness of cell construct is about 1 mm and the cells inside are live and bio-active, irrespective of their internal distribution. The GHNF were prepared by the solution blow method of gelatin, following by dehydrothermal crosslinking. The GHNF showed a mechanical strength strong enough not to allow the shape to deform even in a wet state. The wet GHNF also showed resistance against repeated compression. After human mesenchymal stromal cells (hMSC) were seeded and cultured, the inner distribution in GHNF, the apoptosis, hypoxia inducible factor (HIF)-1α, Ki67, collagen or sulfated glycosaminoglycan (sGAG) secretion of cells were evaluated. The hMSC proliferated inside the GHNF with time while a homogeneous distribution in the number of cells proliferated from the surface to the 1000 μm depth of GHNF was observed. The number of apoptosis and HIF-1α positive cells was significantly low compared with that of polypropylene nonwoven fabrics with the similar fiber diameters and intra-structure. The GHNF were degraded during cell culture, and completely replaced by collagen and sGAG secreted. It is concluded that the GHNF is a promising cell culture scaffold for 3D cell constructs

The Use of an Intermaxillary Fixation Screw for Mandibular Setback Surgery

金沢大学医学部附属病院歯科口腔外科Purpose: To assess skeletal stability after mandibular setback surgery with and without an intermaxillary fixation (IMF) screw. Patients and Methods: The subjects were 40 patients with mandibular prognathism. The subjects underwent sagittal split ramus osteotomy with titanium plate fixation and were divided into 2 groups, 1 with and 1 without an IMF screw. A lateral cephalogram was done preoperatively, immediately after surgery, and 1 month, 3 months, and 6 months postoperatively. The 2 groups were then compared statistically. Results: In the comparison of the time-course change between the 2 groups with repeated measure analysis of variance, there were significant differences in occlusal plane (between subjects, F = 2.517; df = 4; P = .0437) and convexity (between subjects, F = 4.048; df = 4; P = .0038). However, there was no significant difference in the other measurements. Conclusion: This study suggested that in most measurements, there was no significant difference between 2 groups with and without an IMF screw in time-course skeletal change. However, use of IMF screws was helpful for orthognathic surgery as a rigid anchor of IMF. © 2007 American Association of Oral and Maxillofacial Surgeons

Use of the Sonopet ultrasonic curettage device in intraoral vertical ramus osteotomy

金沢大学医学部附属病院歯科口腔外科This study was designed to evaluate the usefulness of the Sonopet UST-2001 (Miwatec Co., Ltd., Kawasaki, Kanagawa, Japan) ultrasonic curettage device, and to assess the outcome after intraoral vertical ramus osteotomy (IVRO). Thirteen Japanese adults (age range 20-41 years, mean age 29.6 years) presented with jaw deformities diagnosed as mandibular prognathism and asymmetry; they all underwent IVRO of the mandible. This procedure was followed by ultrasonic bone curettage using the Sonopet to make a guiding notch or groove in the lateral cortex of the ramus without damaging the vessels and nerves. After surgery, the osteotomy line was evaluated by three-dimensional computed tomography. In all patients, osteotomy with the Sonopet device was achieved safely, with minimal bleeding and no major complications. The distal segment could be moved into its ideal position and all patients achieved their ideal profiles. Ultrasonic bone curettage is a safe method for making a guiding groove, without damage to surrounding tissue, prior to complete IVRO. © 2007 International Association of Oral and Maxillofacial Surgeons

Changes in occlusal force after mandibular ramus osteotomy with and without Le Fort I osteotomy

金沢大学医学部附属病院歯科口腔外科金沢大学大学院医学系研究科がん細胞学The purpose of this study was to evaluate the differences in bite force changes and occlusal contacts after sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) with and without Le Fort I osteotomy. Sixty female patients with diagnosed mandibular prognathism with or without asymmetry were divided into four groups (SSRO, IVRO, SSRO with Le Fort I osteotomy and IVRO with Le Fort I osteotomy). Bite force and occlusal contacts were measured preoperatively and at 1, 3, 6 and 12 months after surgery with pressure-sensitive sheets. The differences among surgical procedures were examined statistically. Maximum bite force and occlusal contacts returned to preoperative levels after between 3 and 6 months. Regarding time-dependent changes in bite force and occlusal contact area, there were no significant differences among the groups. In conclusion, this study suggests that the combination of IVRO or SSRO and Le Fort I osteotomy does not affect postoperative time-dependent changes. © 2006 International Association of Oral and Maxillofacial surgeons

S-100B and neuron-specific enolase as predictors of neurological outcome in patients after cardiac arrest and return of spontaneous circulation: a systematic review

INTRODUCTION: Neurological prognostic factors after cardiopulmonary resuscitation (CPR) in patients with cardiac arrest (CA) as early and accurately as possible are urgently needed to determine therapeutic strategies after successful CPR. In particular, serum levels of protein neuron-specific enolase (NSE) and S-100B are considered promising candidates for neurological predictors, and many investigations on the clinical usefulness of these markers have been published. However, the design adopted varied from study to study, making a systematic literature review extremely difficult. The present review focuses on the following three respects for the study design: definitions of outcome, value of specificity and time points of blood sampling. METHODS: A Medline search of literature published before August 2008 was performed using the following search terms: "NSE vs CA or CPR", "S100 vs CA or CPR". Publications examining the clinical usefulness of NSE or S-100B as a prognostic predictor in two outcome groups were reviewed. All publications met with inclusion criteria were classified into three groups with respect to the definitions of outcome; "dead or alive", "regained consciousness or remained comatose", and "return to independent daily life or not". The significance of differences between two outcome groups, cutoff values and predictive accuracy on each time points of blood sampling were investigated. RESULTS: A total of 54 papers were retrieved by the initial text search, and 24 were finally selected. In the three classified groups, most of the studies showed the significance of differences and concluded these biomarkers were useful for neurological predictor. However, in view of blood sampling points, the significance was not always detected. Nevertheless, only five studies involved uniform application of a blood sampling schedule with sampling intervals specified based on a set starting point. Specificity was not always set to 100%, therefore it is difficult to indiscriminately assess the cut-off values and its predictive accuracy of these biomarkers in this meta analysis. CONCLUSIONS: In such circumstances, the findings of the present study should aid future investigators in examining the clinical usefulness of these markers and determination of cut-off values

Improved methods for detection of β-galactosidase (lacZ) activity in hard tissue

The ß-galactosidase gene (lacZ) of Escherichia coli is widely used as a reporter gene. The expression of lacZ can be detected by enzyme-based histochemical staining using chromogenic substrates such as 5-bromo-4-chloro-3-indolyl-ß-D: -galactoside (X-gal). Because the enzymatic activity of lacZ is vulnerable to high temperatures and acid treatment for demineralization, detection of lacZ on paraffinized sections is difficult, especially for hard tissues, which require demineralization before sectioning in paraffin. To circumvent this problem, whole-mount X-gal staining before sectioning is performed. However, detection of lacZ activity in the center of larger portions of hard whole adult tissues is challenging. In this study, focusing on fixation procedures, we determined the conditions conducive to improved detection of lacZ activity in deeper areas of whole tissues. We used an annexin a5 (Anxa5)-lacZ reporter mouse model in which the Anxa5 expression in hard tissue is indicated by lacZ activity. We found that lacZ activity could be detected throughout the periodontal ligament of adult mice when fixed in 100% acetone, whereas it was not detected in the periodontal ligament around the root apex fixed in glutaraldehyde and paraformaldehyde. This staining could not be detected in wild-type mice. Acetone maintains the lacZ activity within 48 h of fixation at both 4°C and at room temperature. In conclusion, acetone is the optimal fixative to improve permeability for staining of lacZ activity in large volumes of adult hard tissues

Condylar and disc positions after sagittal split ramus osteotomy with and without Le Fort I osteotomy

金沢大学医学部附属病院歯科口腔外科金沢大学大学院医学系研究科がん細胞学Purpose: The purpose of this study is to examine the changes in temporomandibular joint (TMJ) morphology and clinical symptoms after sagittal split ramus osteotomy (SSRO) with and without a Le Fort I osteotomy. Subjects and Methods: Of 45 Japanese patients with mandibular prognathism, 23 underwent SSRO and 22 underwent SSRO in combination with a Le Fort I osteotomy. The TMJ symptoms and joint morphology, including disc tissue, were assessed preoperatively and postoperatively by magnetic resonance imaging (MRI) and axial cephalography. Results: There were significant differences between pre- and postoperative horizontal changes in the condylar long axis on the right side in the group undergoing SSRO (sagittal split ramus osteotomy) alone. However, there were no other significant differences in pre- and postoperative measurements in this group as compared with the group receiving SSRO plus Le Fort I osteotomy, and the preoperative disc position could not be changed in either group. Conclusion: These results suggest that SSRO, either with or without Le Fort I osteotomy, could not change the preoperative disc position or correct anterior disc displacement, although these procedures did improve the symptoms associated with TMJ dysfunction. © 2007 Mosby, Inc. All rights reserved