Photoinduced Phenomena in Liquid Selenium : A Possibility of the Photoinduced Semiconductor-metal Transition

In order to study the dynamics of the semiconductor-metal transition in liquid selenium, we have measured the transient absorption spectra of liquid selenium after illuminating with a pulsed laser. We have observed the disappearance of the optical gap when the pulsed laser with the intensity of 15 mJ/pulse illuminates liquid selenium at 350℃, which means that the photoinduced semiconductor-metal transition occurs. The time variation of the spectra after the illumination suggests that the structural change occurs accompanying the semiconductor-metal transition

Photo-induced Polymerization and the Relaxation in Liquid Sulfur

In order to study dynamical properties of the polymerization transition in liquid sulfur we have measured the transient absorption spectra after illuminating pulsed laser below and above the polymerization temperature, T_p. For the measurement we have developed a specially designed optical cell made of quartz. The thickness of liquid specimen contained in the cell was less than 1μm, which enabled us to measure the change of optical absorption spectra accompanying the polymerization. We have found that the photo-induced polymerization occurs below T_p. When the relaxation to the thermal equilibrium state occurs after stopping the illumination there appear two different relaxation processes, that is, the fast and slow ones. The fast one is observed just after stopping the illumination of pulsed laser and the relaxation time is about 30 seconds. The slow one follows the fast one and the relaxation time is of the order of one or ten minutes. On the basis of these findings we propose a possible idea that the fast relaxation process corresponds to the relaxation from a polymeric chain to a charge-transfer complex and the slow one the relaxation from the charge-transfer complex to the most stable ring molecules

Design and Demonstration of a Neutron Spin Flipper for a New Neutron Reflectometer SHARAKU at J-PARC

AbstractA new neutron reflectometer SHARAKU with vertical sample-plane geometry was installed on the beam line 17 (BL17) at Materials and Life science experiment Facility (MLF) at J-PARC. Magnetism in a thin magnetic film is one of the main targets on SHARAKU and polarizing devices and neutron spin flippers are required. Since polarized neutrons of wavelength from 0.24nm to 0.64nm can be used on SHARAKU, a neutron spin flipper has to control white neutron beam. A two-coil neutron spin flipper (Drabkin spin flipper) is one of the powerful devices to control neutron spin with white beam. In this study, the two-coil flipper was designed and installed in SHARAKU. Demonstration of the two-coil flipper was also performed and polarization of more than 0.95 with wavelengths ranging from 0.24nm to 0.64nm was obtained

Surrounding Gastric Mucosa Findings Facilitate Diagnosis of Gastric Neoplasm as Gastric Adenoma or Early Gastric Cancer

Background and Aim. It is difficult to master the skill of discriminating gastric adenoma from early gastric cancer by conventional endoscopy or magnifying endoscopy combined with narrow-band imaging, because the colors and morphologies of these neoplasms are occasionally similar. We focused on the surrounding gastric mucosa findings in order to determine how to discriminate between early gastric cancer and gastric adenoma by analyzing the characteristics of the gastric background mucosa. Methods. We retrospectively examined 146 patients who underwent endoscopic submucosal dissection for gastric neoplasm between October 2009 and January 2015. The boundary of atrophic gastritis was classified endoscopically according to the Kimura-Takemoto classification system. Of 146 lesions, 63 early gastric cancers and 21 gastric adenomas were ultimately evaluated and assessed. Results. Almost all gastric adenomas were accompanied by open-type gastritis, whereas 47 and 16 early gastric cancers were accompanied by open-type and closed-type gastritis, respectively (p = 0.037). Conclusions. The evaluation of the boundary of atrophic gastritis associated with gastric neoplasms appears to be useful for discrimination between early gastric cancer and gastric adenoma. When gastric neoplasm is present in the context of surrounding localized gastric atrophy, gastric cancer is probable but not certain

Lethal Bleeding from a Duodenal Cancerous Ulcer Communicating with the Superior Mesenteric Artery in a Patient with Pancreatic Head Cancer

Pancreatic cancer often invades the duodenum and causes obstruction, but rarely causes massive duodenal bleeding. A 68-year-old male was admitted to our hospital because of vomiting. Enhanced abdominal CT showed a hypovascular tumor with air bubbles in the uncinate process of the pancreas. The tumor invaded the duodenum and metastasized to the liver and peritoneum. The main trunk of the superior mesenteric artery (SMA) was circumferentially involved. After admission, he had hematemesis and melena. Emergency gastroduodenoscopy revealed pulsating vessels in the third portion of the duodenum and he eventually experienced hemorrhagic shock. Severe bleeding occurred from his mouth and anus like a catastrophic flood. It was difficult to sustain blood pressure even with massive blood transfusion with pumping. After insertion of an intra-aortic balloon occlusion catheter, the massive bleeding was eventually stopped. Although we attempted interventional radiography, aortography revealed direct communication between the main SMA trunk and the duodenal lumen. The tumor was considered anatomically and oncologically unresectable. Thus, we did not perform further intervention. The patient died 2 h after angiography. Herein, we report the case of pancreatic head cancer causing lethal bleeding associated with tumor-involved SMA. Duodenal bleeding associated with pancreatic cancer invasion should be considered as an oncogenic emergency

Toxoplasma Effector TgIST Targets Host IDO1 to Antagonize the IFN-γ-Induced Anti-parasitic Response in Human Cells

Toxoplasma gondii is an important human and animal pathogen that causes life-threatening toxoplasmosis. Interferon-γ (IFN-γ) is critical for anti-T. gondii cell-autonomous immunity in both humans and mice. To proliferate efficiently within the hosts, virulent strains of T. gondii can suppress IFN-γ-dependent immunity. During parasite infection, it is well-characterized that various virulence effectors are secreted to transcriptionally or post-translationally target IFN-γ-inducible GTPases, which are essential for anti-parasite responses in mice. However, the role of IFN-γ-inducible GTPases in anti-T. gondii responses in human cells is controversial since they are non-functional or absent in humans. Instead, IFN-γ-induced tryptophan degradation by indole-2,3-dioxygenase (IDO) is important for the anti-T. gondii human response. To date, the T. gondii virulent mechanism targeting IDO in human cells remains elusive. Here we show that although humans possess two IDO isozymes, IDO1 and IDO2, human cells of various origins require IDO1 but not IDO2 for IFN-γ-induced cell-autonomous immunity to T. gondii. T. gondii secretes an effector TgIST to inhibit IDO1 mRNA expression. Taken together, the data suggests that T. gondii possesses virulence programs operated by TgIST to antagonize IFN-γ-induced IDO1-mediated anti-parasite cell-autonomous immunity in human cells

Novel and Conserved Protein Macoilin Is Required for Diverse Neuronal Functions in Caenorhabditis elegans

Neural signals are processed in nervous systems of animals responding to variable environmental stimuli. This study shows that a novel and highly conserved protein, macoilin (MACO-1), plays an essential role in diverse neural functions in Caenorhabditis elegans. maco-1 mutants showed abnormal behaviors, including defective locomotion, thermotaxis, and chemotaxis. Expression of human macoilin in the C. elegans nervous system weakly rescued the abnormal thermotactic phenotype of the maco-1 mutants, suggesting that macoilin is functionally conserved across species. Abnormal thermotaxis may have been caused by impaired locomotion of maco-1 mutants. However, calcium imaging of AFD thermosensory neurons and AIY postsynaptic interneurons of maco-1 mutants suggest that macoilin is required for appropriate responses of AFD and AIY neurons to thermal stimuli. Studies on localization of MACO-1 showed that C. elegans and human macoilins are localized mainly to the rough endoplasmic reticulum. Our results suggest that macoilin is required for various neural events, such as the regulation of neuronal activity

Anti-Prion Activity of Brilliant Blue G

BACKGROUND: Prion diseases are fatal neurodegenerative disorders with no effective therapy currently available. Accumulating evidence has implicated over-activation of P2X7 ionotropic purinergic receptor (P2X7R) in the progression of neuronal loss in several neurodegenerative diseases. This has led to the speculation that simultaneous blockade of this receptor and prion replication can be an effective therapeutic strategy for prion diseases. We have focused on Brilliant Blue G (BBG), a well-known P2X7R antagonist, possessing a chemical structure expected to confer anti-prion activity and examined its inhibitory effect on the accumulation of pathogenic isoforms of prion protein (PrPres) in a cellular and a mouse model of prion disease in order to determine its therapeutic potential. PRINCIPAL FINDINGS: BBG prevented PrPres accumulation in infected MG20 microglial and N2a neural cells at 50% inhibitory concentrations of 14.6 and 3.2 µM, respectively. Administration of BBG in vivo also reduced PrPres accumulation in the brains of mice with prion disease. However, it did not appear to alleviate the disease progression compared to the vehicle-treated controls, implying a complex role of P2X7R on the neuronal degeneration in prion diseases. SIGNIFICANCE: These results provide novel insights into the pathophysiology of prion diseases and have important implications for the treatment

液体イオウにおける光誘起重合化とその緩和過程に関する研究

第1章 序論 / p1 　1.1 結晶構造 / p1 　1.2 電子状態 / p4 　1.3 液体イオウの重合化に伴う諸物性の変化 / p6 　1.4 本研究の目的 / p17 第2章 実験方法 / p20 　2.1 測定装置 / p20 　2.2 測定方法 / p26 　2.3 計算方法 / p28 第3章 結果および考察 / p33 　3.1 重合転移温度Tp以下における光誘起現象 / p33 　3.2 緩和時間の温度変化 / p60 　3.3 照射条件の違いによる緩和時間の変化 / p66 　3.4 巨大高分子の生成 / p75 第4章 まとめ / p90 謝辞 / p92 付録A 石英ガラス製光学セルの作製方法 / p93 付録B 長寿命生成物として考えられるもののもう一つの可能性 / p110 参考文献 / p124広島大学(Hiroshima University)博士(学術)Sciencedoctora