Fluorescence properties of pyrene derivative aggregates formed in polymer matrix depending on concentration

We investigated the fluorescence properties of dye aggregates formed in a poly(vinylalcohol) (PVA) matrix by phase separation. Trimethyl-(2-oxo-2-pyrene-1-yl-ethyl)-ammonium bromide (PyAm) was used as a fluorescent dye molecule. The size of PyAm aggregates in the PVA thin films were increased with increasing dye concentration, which was confirmed by atomic force microscope (AFM) measurements. The fluorescence spectra of PyAm in the PVA film at a lower concentration of 0.001 mol% only showed the monomer emission. The fluorescence peak shifted to the red with increasing dye concentration, which was assigned to a dimer or excimer-like emission. Changes in the fluorescence spectra relate to the formation of aggregates in the films. The fluorescence anisotropy decay time constant increases with increasing PyAm concentration up to the order of 100 ps. It is suggested that the exciton efficiently diffuses within the aggregates, and then was trapped at the dimer sites. We also demonstrated the application for gas sensing of nitroaromatics: 2,4-dinitrotoulene (DNT) based on the fluorescence quenching by the photoinduced electron transfer. The quenching efficiency of PyAm fluorescence reached about 43% under concentration of 2.0 mol%. The fluorescence intensity efficiently quenched at the dimer or excimer-like band. These results indicated that the efficient fluorescence quenching increases the reaction probability between PyAm and DNT by the exciton diffusion in the aggregates, called "amplified quenching''. The nano-sized aggregates of PyAm formed in the PVA films are responsible for high sensitivity as an artificial fluorescent chemosensor for vapors of the nitroaromatics.ArticlePHYSICAL CHEMISTRY CHEMICAL PHYSICS. 12(36):10923-10927 (2010)journal articl

Multi-Physics Simulation Platform and Multi-Layer Metal Technology for CMOS-MEMS Accelerometer with Gold Proof Mass

This chapter describes technical features and solutions to realize a highly sensitive CMOS-MEMS accelerometer with gold proof mass. The multi-physics simulation platform for designing the CMOS-MEMS device has been developed to understand simultaneously both mechanical and electrical behaviors of MEMS stacked on LSI. MEMS accelerometer fabrication process is established by the multi-layer metal technology, which consists of the gold electroplating and the photo-sensitive polyimide film. The proposed MEMS accelerometers are fabricated and evaluated to verify the effectiveness of the proposed techniques regarding sub-1G MEMS and arrayed MEMS devices. The experimental results show that the Brownian noise of the sub-1G MEMS accelerometer can achieve 780 nG/(Hz)1/2 and the arrayed MEMS accelerometer has a wide detection, ranging from 1.0 to 20 G. Moreover, using the developed simulation platform, we demonstrate the proposed capacitive CMOS-MEMS accelerometer implemented by the multi-layer metal technology. In conclusion, it is confirmed that the multi-physics simulation platform and the multi-layer metal technology for the CMOS-MEMS device have a potential to realize a nano-gravity sensing technology

Regulation of Tumor Immunity by Tumor/Dendritic Cell Fusions

The goal of cancer vaccines is to induce antitumor immunity that ultimately will reduce tumor burden in tumor environment. Several strategies involving dendritic cells- (DCs)- based vaccine incorporating different tumor-associated antigens to induce antitumor immune responses against tumors have been tested in clinical trials worldwide. Although DCs-based vaccine such as fusions of whole tumor cells and DCs has been proven to be clinically safe and is efficient to enhance antitumor immune responses for inducing effective immune response and for breaking T-cell tolerance to tumor-associated antigens (TAAs), only a limited success has occurred in clinical trials. This paper reviews tumor immune escape and current strategies employed in the field of tumor/DC fusions vaccine aimed at enhancing activation of TAAs-specific cytotoxic T cells in tumor microenvironment.Foundation for the Promotion of Cancer Research; Mitsui Life Social Welfare Foundation; Grants-in-Aid for Scientific Research from the Ministry of Education, Cultures, Sports, Science, and Technology of Japan; Grant-in-Aid of the Japan Medical Association; Takeda Science Foundation; Pancreas Research Foundation of Japa

Venous Thromboembolism in Patients with Acute Thoracolumbar Spinal Cord Injury

Venous thromboembolism (VTE) is a major complication in patients with acute spinal cord injury. There are few reports of VTE with acute thoracolumbar spinal cord injury (TLSCI). We assessed the incidence of VTE with acute TLSCI using color Doppler ultrasonography. We retrospectively assessed 75 patients with acute TLSCI (T1 to L1). All patients were surgically treated. VTE of the lower extremity and pelvis was assessed using color Doppler ultrasound regardless of whether symptoms were present. This retrospective study included patients who were assessed between 6 and 10 days (mean 8.1 days) after injury. VTE was detected in 27 of the 75 patients (35.7%) with or without paralysis. Of the 13 patients who had complete motor paralysis, 8 (62%) had VTE; of the 31 patients with incomplete motor paralysis, 10 (32%) had VTE, and of the 31 patients without motor paralysis, 9 (29%) had VTE. Among the patients with TLSCI, those with VTE had a significantly higher mean age than those without. The incidence of VTE in TLSCI patients is not related to the severity of paralysis in a Japanese population. The incidence appears to be related primarily to age

Reconstruction With Ipsilateral Fibula Transfer With Pasteurized Bone After Excision of Bone Sarcoma of the Tibia

We report a technique of implantation of the ipsilateral vascularized fibula with pasteurized recycled bone after excision of tibia sarcoma in two cases. Plate and screws were used for osteosynthesis of the tibia or talus, vascularized fibula, and pasteurized bone. Microsurgery is not necessary for this reconstruction technique. Two patients who underwent this technique have obtained good functional results without tumor relapse 5 and 6 years after operation. The technique produced excellent results with regard to tibial reconstruction in these cases. We found it to be simple, speedy, safe, and a low cost technique by use of recycled bone

Multipotent Neurotrophic Effects of Hepatocyte Growth Factor in Spinal Cord Injury

Spinal cord injury (SCI) results in neural tissue loss and so far untreatable functional impairment. In addition, at the initial injury site, inflammation induces secondary damage, and glial scar formation occurs to limit inflammation-mediated tissue damage. Consequently, it obstructs neural regeneration. Many studies have been conducted in the field of SCI; however, no satisfactory treatment has been established to date. Hepatocyte growth factor (HGF) is one of the neurotrophic growth factors and has been listed as a candidate medicine for SCI treatment. The highlighted effects of HGF on neural regeneration are associated with its anti-inflammatory and anti-fibrotic activities. Moreover, HGF exerts positive effects on transplanted stem cell differentiation into neurons. This paper reviews the mechanisms underlying the therapeutic effects of HGF in SCI recovery, and introduces recent advances in the clinical applications of HGF therapy

H. pylori-Eradication Therapy Increases RUNX3 Expression in the Glandular Epithelial Cells in Enlarged-Fold Gastritis

Helicobacter pylori (HP)-eradication therapy increases Runt domain transcription factor 3 (RUNX3) expression in the glandular epithelial cells in enlarged-fold gastritis. The aim of this study is to evaluate expression of the RUNX3 protein, the product of a gastric tumor suppression gene, and mutagenic oxidative stress in human gastric mucosal specimens obtained from patients with HP-induced enlarged-fold gastritis. Methods. RUNX3 expression was immunohistochemically scored and the degree of the mucosal oxidative stress was directly measured by the chemiluminescense (ChL) assay in the biopsy specimens. Results. RUNX3 expression was detected in the gastric epithelial cells. HP-eradication significantly increased RUNX3 expression in the glandular epithelium of the corpus, however, no change was observed in those of the antrum. A fourfold higher mucosal ChL value was observed in the corpus as compared with that in the antrum. HP-eradication significantly decreased the mucosal ChL values in both portions of the stomach to nearly undetectable levels. Conclusion. The glandular epithelium is exposed to a high level of carcinogenic oxidative stress and shows low levels of expression of the tumor suppressive molecule, RUNX3; however, this expression was restored after HP-eradication, suggesting the high risk of carcinogenesis associated with HP-induced enlarged-fold gastritis of the corpus

Biomechanical Comparison of Posterior Fixation Using Spinal Instrumentation and Conventional Posterior Plate Fixation in Unstable Vertical Sacral Fracture

Vertical sacral fracture is one of the most difficult fractures to treat. Posterior fixation using spinal dual rods is a novel method for treating this fracture, but its biomechanical strength has not yet been reported. The aim of this study was to evaluate the biomechanical strength produced by posterior fixation using spinal instrumentation. Sacral fractures were created in eight pelvic bone models and classified into a posterior plate fixation group [P group, n＝4] and a spinal instrumentation group [R group, n＝4]. The biomechanical strength was tested by pushing down on the S1 vertebra from the top. The mean maximum loads were 1,057.4 N and 1,489.4 N in the P and R groups, respectively (p＝0.014). The loads applied to the construct at displacements of 5mm and 7.5mm from the start of the universal testing machine loading were also significantly higher in the R group. The mean stiffness levels in the P and R groups were 88.3N/mm and 119.6N/mm, respectively (p＝0.014). Posterior fixation using spinal instrumentation is biomechanically stronger than conventional posterior plate fixation. This procedure may be the optimal method for treating unstable sacral fracture fixation