185 research outputs found
Bipyridyl-substituted benzo[1,2,3]triazoles as a thermally stable electron transporting material for organic light-emitting devices
We developed new electron-transporting materials (ETMs) for organic light-emitting devices (OLEDs) based on benzo[1,2,3] triazole and two bipyridines. Four derivatives based on the same skeleton were synthesized with four different substituents: phenyl (BpyBTAZ-Ph), biphenyl (-BP), m-terphenyl (-mTP), and o-terphenyl (-oTP). These BpyBTAZ compounds have good thermal stabilities, and their decomposition temperatures were greater than 410 degrees C, which is significantly higher than that of tris(8-quinolinolato) aluminium (Alq), the conventional OLED material. BpyBTAZ compounds show preferable amorphous nature, and moreover, the glass transition temperatures (T(g)s) of both BpyBTAZ-TP compounds exceed 100 degrees C. Furthermore, BpyBTAZ-BP exhibits no melting point and is fully amorphous. The electron affinities of the materials are as large as 3.3 eV and their electron mobility is sufficiently high. These characteristics accounted for a reduction in the operational voltage of OLEDs with BpyBTAZ compounds compared with the reference device with Alq as an ETM. Specifically, the electron mobility of all the BpyBTAZ compounds exceeds 1 x 10(-4) cm(2) V(-1) s(-1) at an electric field of 1 MV cm(-1). In addition, it was revealed that both BpyBTAZ-TP-based devices showed longer luminous lifetimes and smaller voltage increases during continuous operation at 50 mA cm(-2), compared with the Alq reference device.ArticleJOURNAL OF MATERIALS CHEMISTRY. 21(32):11791-11799 (2011)journal articl
Neonatal Intrathymic Splenocyte Injection Yields Prolonged Cardiac Xenograft Survival
Intrathymic (i.t.) injection of allogenic cells without administration of anti-lymphocyte serum (ALS) in neonatal recipients has induced donor-specific tolerance to subsequent cardiac allografts in rats. This study examines whether similar tactics can be successfully applied to a hamster-to-rat cardiac xenotransplantation model. Lewis neonates on their first day of life underwent i.t., subcutaneous (s.c.), intraperitoneal (i.p.), or intravenous (i.v.) injections of 5 x 10(7) Golden Syrian hamster splenocytes. After six weeks, the rats underwent heterotopic cardiac transplantation of hamster hearts. Cyclophosphamide (CyP) was administered on the day before surgery and postoperatively to suppress antibody-mediated graft rejection. Rats given splenocytes with 80 mg/kg of CyP had the following graft survival times: 8 to 12 days for i.t. injection (mean, 9.4 days); 5 to 7 days for s.c. injection (mean, 6.6 days); 4 to 11 days for i.p. injection (mean, 7.4 days); and 4 to 13 days for i.v. injection (mean, 7.9 days). Only the extension of graft survival produced by i.t. injection was statistically significant in comparison with the rats given only CyP treatment (mean, 7.5 days; P < 0.05). Thus, it appears that i.t. injection of xenogenic splenocytes in neonatal recipients with administration of CyP, but without ALS, can prolong xenograft survival. This biological intervention may be most useful in pediatric xenotransplantation when combined with other immunomodulation techniques.</p
Role of Sphingomyelinase in Infectious Diseases Caused by Bacillus cereus
Bacillus cereus (B. cereus) is a pathogen in opportunistic infections. Here we show that Bacillus cereus sphingomyelinase (Bc-SMase) is a virulence factor for septicemia. Clinical isolates produced large amounts of Bc-SMase, grew in vivo, and caused death among mice, but ATCC strains isolated from soil did not. A transformant of the ATCC strain carrying a recombinant plasmid containing the Bc-SMase gene grew in vivo, but that with the gene for E53A, which has little enzymatic activity, did not. Administration of an anti-Bc-SMase antibody and immunization against Bc-SMase prevented death caused by the clinical isolates, showing that Bc-SMase plays an important role in the diseases caused by B. cereus. Treatment of mouse macrophages with Bc-SMase resulted in a reduction in the generation of H2O2 and phagocytosis of macrophages induced by peptidoglycan (PGN), but no effect on the release of TNF-α and little release of LDH under our experimental conditions. Confocal laser microscopy showed that the treatment of mouse macrophages with Bc-SMase resulted in the formation of ceramide-rich domains. A photobleaching analysis suggested that the cells treated with Bc-SMase exhibited a reduction in membrane fluidity. The results suggest that Bc-SMase is essential for the hydrolysis of SM in membranes, leading to a reduction in phagocytosis
Therapeutic Effect of Anti-TNF-α Antibody and Levofloxacin(LVFX)in a Mouse Model of Enterohemorrhagic Escherichia coli O157 Infection
マウスに腸管出血性大腸菌O157を感染させ、抗TNF-α抗体投与による感染防御効果を調べた。抗TNF-α抗体単独投与群では感染による症状の発現及び組織学的な変化は観察されなかったが、糞便中に少量のO157が証明された。本抗体にLVFXを併用した場合には糞便中のO157は完全に除去されたので、両者の併用により良好な治療結果が得られると考える
チタン鋳造における鋳型温度の影響
The purpose of this study was to evaluate the titanium castability with a vacuum pressured type casting machine. We tested ethyl-silicate bonded investment "TITAVESTPS" of metal frame work. Four different mold temperatures (room temperature, 300℃, 600℃, and 900℃) were prepared for the present study, and casting was done in five times in each condition. When the mold temperature increased, high percentage of castability was gained. Mold temperature showed a highly significant (p<0.001) correlation on the castability. These results indicate that high performance of castability on the titanium was achieved when the mold temperature increased by using vacuum pressured type casting machine
Resurrection of a Bull by Cloning from Organs Frozen without Cryoprotectant in a −80°C Freezer for a Decade
Frozen animal tissues without cryoprotectant have been thought to be inappropriate for use as a nuclear donor for somatic cell nuclear transfer (SCNT). We report the cloning of a bull using cells retrieved from testicles that had been taken from a dead animal and frozen without cryoprotectant in a −80°C freezer for 10 years. We obtained live cells from defrosted pieces of the spermatic cords of frozen testicles. The cells proliferated actively in culture and were apparently normal. We transferred 16 SCNT embryos from these cells into 16 synchronized recipient animals. We obtained five pregnancies and four cloned calves developed to term. Our results indicate that complete genome sets are maintained in mammalian organs even after long-term frozen-storage without cryoprotectant, and that live clones can be produced from the recovered cells
Clinical Outcome of Patients with Pelvic and Retroperitoneal Bone and Soft Tissue Sarcoma : A Retrospective Multicenter Study in Japan
This study aimed to retrospectively analyze the clinical outcomes of patients with pelvic and retroperitoneal bone and soft tissue sarcoma (BSTS). Overall, 187 patients with BSTS in the pelvis and retroperitoneal region treated at 19 specialized sarcoma centers in Japan were included. The prognostic factors related to overall survival (OS), local control (LC), and progression-free survival (PFS) were evaluated. The 3-year OS and LC rates in the 187 patients were 71.7% and 79.1%, respectively. The 3-year PFS in 166 patients without any distant metastases at the time of primary tumor diagnosis was 48.6%. Osteosarcoma showed significantly worse OS and PFS than other sarcomas of the pelvis and retroperitoneum. In the univariate analyses, larger primary tumor size, soft tissue tumor, distant metastasis at the time of primary tumor diagnosis, P2 location, chemotherapy, and osteosarcoma were poor prognostic factors correlated with OS. Larger primary tumor size, higher age, soft tissue tumor, chemotherapy, and osteosarcoma were poor prognostic factors correlated with PFS in patients without any metastasis at the initial presentation. Larger primary tumor size was the only poor prognostic factor correlation with LC. This study has clarified the epidemiology and prognosis of patients with pelvic and retroperitoneal BSTS in Japan
The Quiescent Intracluster Medium in the Core of the Perseus Cluster
Clusters of galaxies are the most massive gravitationally-bound objects in
the Universe and are still forming. They are thus important probes of
cosmological parameters and a host of astrophysical processes. Knowledge of the
dynamics of the pervasive hot gas, which dominates in mass over stars in a
cluster, is a crucial missing ingredient. It can enable new insights into
mechanical energy injection by the central supermassive black hole and the use
of hydrostatic equilibrium for the determination of cluster masses. X-rays from
the core of the Perseus cluster are emitted by the 50 million K diffuse hot
plasma filling its gravitational potential well. The Active Galactic Nucleus of
the central galaxy NGC1275 is pumping jetted energy into the surrounding
intracluster medium, creating buoyant bubbles filled with relativistic plasma.
These likely induce motions in the intracluster medium and heat the inner gas
preventing runaway radiative cooling; a process known as Active Galactic
Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus
cluster core, which reveal a remarkably quiescent atmosphere where the gas has
a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from
the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s
is found across the 60 kpc image of the cluster core. Turbulent pressure
support in the gas is 4% or less of the thermodynamic pressure, with large
scale shear at most doubling that estimate. We infer that total cluster masses
determined from hydrostatic equilibrium in the central regions need little
correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July
- …