6. Heating Structure of Laser-Driven Detonations(<Special Topic Article>New Trend of Sciences with High Energy Lasers)

デトネーションとは,衝撃波とそれに伴う流体加熱領域とが一体となって媒質中を伝播する現象であり,流体加熱機構には化学燃焼,核燃焼,レーザー加熱の3つが知られている.レーザー駆動デトネーションについては,現象は1960年代から知られているものの,詳細はほとんどわかっていない.本章では,大スポット径レーザー照射によって発生させた平面波的なレーザー駆動デトネーションの加熱構造について,最近の実験結果を紹介する

Spectroscopic Observation of He Arcjet Plasma Expanding Through a Converging and Diverging Slit Nozzle

An arcjet plasma generator with a converging and diverging slit nozzle was constructed. This plasma source allowed us to directly observe the arc plasma in the discharge section, which provided useful information about a transition from ionizing thermal plasma to recombining phase. Spatial distributions of the electron temperature and density in the rectangular shaped anode nozzle were evaluated by visible emission spectroscopy. The temperature and density for a discharge current of 20 A were determined to be 0.18 eV and 3.7×1013 cm-3, respectively, at the nozzle throat. The values on the jet axis were compared with those calculated by the gas dynamic theory on one dimensional slit nozzle

Influence of adding carbon nanotubes on photoelectric conversion properties of dye-doped titania gel

Multiwalled carbon nanotubes (MWCNTs) were incorporated into amorphous dye-doped titania gel by the sol-gel method at room temperature. The working electrodes were prepared by coating the ITO glass with the sol-gel titania precursor containing the dye and MWCNTs. The photoelectric conversion properties of the electrodes were examined by simple spectroscopic and electric measurements. The photocurrent spectrum originated from the absorption of the dye. The short circuit photocurrent was enhanced by adding a small amount of MWCNTs evenly to the amorphous dye-doped titania gel. The open circuit voltage was due to the semiconducting characteristics property of the titania gel. The experimental results indicated the electron transport from the dye excited states to the MWCNTs through the titania gel. The MWCNTs functioned as bridges between the titania and ITO. Steam treatment of the titania gel electrodes significantly increased the photoelectric performance due to crystallization of the titania and enhancement of the dye-titania interaction forming the chelate complex on the titania particle surface.ArticleRESEARCH ON CHEMICAL INTERMEDIATES. 38(8):1857-1869 (2012)journal articl

Thrust Measurement of a Multicycle Partially Filled Pulse Detonation Rocket Engine

In the present research, we experimentally verified the partial-fill effect in a multicycle pulse detonation rocketengine. The intermittent thrust of a pulse detonation rocket engine was measured by using a spring-dampermechanism that smoothed this intermittent thrust in the time direction. The intermittent mass flow rates wereassessed by gas cylinder pressure or mass difference measurement. The maximum specific impulse was 305 9 s atan ethylene and oxygen propellant fill fraction of 0:130 0:004. When the fill fraction was greater than 0.130, thespecific impulse was increased as the partial-fill fraction was decreased. When the fill fraction was less than 0.130, thespecific impulse was sharply decreased as the partial-fill fraction was decreased. This decrease was due to diffusionbetween propellant and purge gases and the short length of the transition from deflagration to detonation. Themulticycle pulse detonation rocket engine had a partial-fill effect that may have been mainly due to the suctioned airand was consistent with the single-cycle partial-fill model of Endo et al

Synthetic RNA-protein complex shaped like an equilateral triangle.

Synthetic nanostructures consisting of biomacromolecules such as nucleic acids have been constructed using bottom-up approaches. In particular, Watson-Crick base pairing has been used to construct a variety of two- and three-dimensional DNA nanostructures. Here, we show that RNA and the ribosomal protein L7Ae can form a nanostructure shaped like an equilateral triangle that consists of three proteins bound to an RNA scaffold. The construction of the complex relies on the proteins binding to kink-turn (K-turn) motifs in the RNA, which allows the RNA to bend by ∼ 60° at three positions to form a triangle. Functional RNA-protein complexes constructed with this approach could have applications in nanomedicine and synthetic biology

IL-1β Acts in Synergy with Endogenous IL-1β in A375-S2 Human Melanoma Cell Apoptosis Through Mitochondrial Pathway

Interleukin-1β (IL-1β) is a pivotal proinflammatory cytokine. To investigate the mechanism of IL-1β-induced cell death in human malignant melanoma A375-S2 cells, MTT assay, photomicroscopical observation, DNA agarose gel electrophoresis, radioimmunoassay and Western blot analysis were carried out. IL-1β did not only induce nuclear condensation and DNA fragmentation, but also increased degradation of two substrates of caspase-3, poly ADP-ribose polymerase (PARP) and inhibitor of caspase-activated DNase (ICAD). Simultaneously, release of precursor of IL-1β (pro-IL-1β) and endogenous IL-1β production were involved in the apoptotic process. IL-1β enhanced the ratio of Bax/Bcl-2 and Bax/Bcl-xL expression and up-regulated apoptosis inducing factor (AIF) expression, which required the activation of downstream caspases. These results suggest that IL-1β induces endogenous IL-1β production, enhances cleavage of caspase downstream substrates and promotes mitochondria mediated apoptosis in A375-S2 cells

Nel positively regulates the genesis of retinal ganglion cells by promoting their differentiation and survival during development

Peer reviewedPublisher PD

Lubiprostone Decreases the Small Bowel Transit Time by Capsule Endoscopy: An Exploratory, Randomised, Double-Blind, Placebo-Controlled 3-Way Crossover Study

The aim of this study was to investigate the usefulness of lubiprostone for bowel preparation and as a propulsive agent in small bowel endoscopy. Six healthy male volunteers participated in this randomized, 3-way crossover study. The subjects received a 24 μg tablet of lubiprostone 60 minutes prior to the capsule ingestion for capsule endoscopy (CE) and a placebo tablet 30 minutes before the capsule ingestion (L-P regimen), a placebo tablet 60 minutes prior to CE and a 24 μg tablet of lubiprostone 30 minutes prior to CE (P-L regimen), or a placebo tablet 60 minutes prior to r CE and a placebo tablet again 30 minutes prior to CE (P-P regimen). The quality of the capsule endoscopic images and the amount of water in the small bowel were assessed on 5-point scale. The median SBTT was 178.5 (117–407) minutes in the P-P regimen, 122.5 (27–282) minutes in the L-P regimen, and 110.5 (11–331) minutes in the P-L regimen (P=0.042). This study showed that the use of lubiprostone significantly decreased the SBTT. We also confirmed that lubiprostone was effective for inducing water secretion into the small bowel during CE

Rebleeding rate after interventional therapy directed by capsule endoscopy in patients with obscure gastrointestinal bleeding

<p>Abstract</p> <p>Background</p> <p>The precise role of capsule endoscopy in the diagnostic algorithm of obscure gastrointestinal bleeding has yet to be determined. Despite the higher diagnostic yield of capsule endoscopy, the actual impact on clinical outcome remains poorly defined. The aim of this study was to evaluate the follow-up results of patients with obscure gastrointestinal bleeding to determine which management strategies after capsule endoscopy reduced rebleeding.</p> <p>Methods</p> <p>All patients in whom the cause of obscure gastrointestinal bleeding was investigated between May 2004 and March 2007 were studied retrospectively. We evaluated the clinical outcome of patients with obscure gastrointestinal bleeding after capsule endoscopy using the rebleeding rate as the primary outcome.</p> <p>Results</p> <p>Seventy-seven patients with obscure gastrointestinal bleeding underwent capsule endoscopy. Capsule endoscopy identified clinically significant findings that were thought to be the sources of obscure gastrointestinal bleeding in 58.4% of the patients. The overall rebleeding rate was 36.4%. The rebleeding rate was significantly higher among patients with insignificant findings than among those with significant findings (<it>p </it>= 0.036). Among the patients in whom capsule endoscopy produced significant findings, the rebleeding rate of the patients who underwent therapeutic interventions was significantly lower than that in those who did not undergo intervention (9.5% vs 40.0%, <it>p </it>= 0.046).</p> <p>Conclusion</p> <p>Follow-up and further aggressive interventions are necessary for patients with obscure gastrointestinal bleeding and significant capsule endoscopy findings to reduce the chance of rebleeding.</p

Metformin efficacy and safety for colorectal polyps: a double-blind randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Colorectal cancer is one of the major neoplasms and a leading cause of cancer death worldwide, and new preventive strategies are needed to lower the burden of this disease. Metformin, a biguanide, which is widely used for treating diabetes mellitus, has recently been suggestive to have a suppressive effect on tumorigenesis and cancer cell growth. In a previous study conducted in non-diabetic subjects, we showed that oral short-term low-dose metformin suppressed the development of colorectal aberrant crypt foci (ACF). ACF have been considered as a useful surrogate biomarker of CRC, although the biological significance of these lesions remains controversial. We devised a prospective randomized controlled trial to evaluate the chemopreventive effect of metformin against metachronous colorectal polyps and the safety of this drug in non-diabetic post-polypectomy patients.</p> <p>Methods/Design</p> <p>This study is a multi-center, double-blind, placebo-controlled, randomized controlled trial to be conducted in non-diabetic patients with a recent history of undergoing colorectal polypectomy. All adult patients visiting the Yokohama City University hospital or affiliated hospitals for polypectomy shall be recruited for the study. Eligible patients will then be allocated randomly into either one of two groups: the metformin group and the placebo group. Patients in the metformin group shall receive oral metformin at 250 mg per day, and those in the placebo group shall receive an oral placebo tablet. At the end of 1 year of administration of metformin/placebo, colonoscopy will be performed to evaluate the polyp formation.</p> <p>Discussion</p> <p>This is the first study proposed to explore the effect of metformin against colorectal polyp formation. Metformin activates AMPK, which inhibits the mammalian target of rapamycin (mTOR) pathway. The mTOR pathway plays an important role in the cellular protein translational machinery and cell proliferation. Patients with type 2 diabetes taking under treatment with metformin have been reported to be at a lower risk of cancer development than those not taking under treatment with metformin. We showed in a previous study that metformin suppressed the formation of human colorectal ACF. We therefore decided to conduct a study to determine whether metformin might suppress the formation of human colorectal polyps.</p> <p>Trial registration</p> <p>This trial has been registered in the University hospital Medical Information Network (UMIN) Clinical Trials Registry as <a href="http://www.clinicaltrials.gov/ct2/show/UMIN000006254">UMIN000006254</a></p