229 research outputs found
Dust Size Growth and Settling in a Protoplanetary Disk
We have studied dust evolution in a quiescent or turbulent protoplanetary
disk by numerically solving coagulation equation for settling dust particles,
using the minimum mass solar nebular model. As a result, if we assume an
ideally quiescent disk, the dust particles settle toward the disk midplane to
form a gravitationally unstable layer within 2x10^3 - 4x10^4 yr at 1 - 30 AU,
which is in good agreement with an analytic calculation by Nakagawa, Sekiya, &
Hayashi (1986) although they did not take into account the particle size
distribution explicitly. In an opposite extreme case of a globally turbulent
disk, on the other hand, the dust particles fluctuate owing to turbulent motion
of the gas and most particles become large enough to move inward very rapidly
within 70 - 3x10^4 yr at 1 - 30 AU, depending on the strength of turbulence.
Our result suggests that global turbulent motion should cease for the
planetesimal formation in protoplanetary disks.Comment: 27 pages, 8 figures, accepted for publication in the Ap
Alpha-i Adrenoceptors Mediate Splanchnic Nerve Inhibition of Pentagastrin-Induced Gastric Acid Secretion and Mucosal Blood Flow in Rats
ABSTRACT Effects of Stimulation of the sympathetic nervous System on pentagastrin-induced increases in gastric acid secretion and mucosal blood flow (MBF) were studied in anesthetized, gastric flstula rats. Gastric acid secretion and MBF were increased b
TiO2-Supported Re as a General and Chemoselective Heterogeneous Catalyst for Hydrogenation of Carboxylic Acids to Alcohols
TiO2-supported Re, Re/TiO2, was found to promote selective hydrogenation of carboxylic acids having aromatic and aliphatic moieties to the corresponding alcohols. Re/TiO2 showed superior results compared to other transition-metal-loaded TiO2 and supported Re catalysts for selective hydrogenation of 3-phenylpropionic acid. 3phenylpropanol was produced in 97% yield under mild conditions (5 MPa H-2 at 140 degrees C). Contrary to typical heterogeneous catalysts, Re/TiO2 does not lead to the formation of dearomatized byproducts. The catalyst is recyclable and shows a wide substrate scope in the synthesis of alcohols (22 examples; up to 97% isolated yield)
Virtual turning points and bifurcation of Stokes curves for higher order ordinary differential equations
For a higher order linear ordinary differential operator P, its Stokes curve
bifurcates in general when it hits another turning point of P. This phenomenon
is most neatly understandable by taking into account Stokes curves emanating
from virtual turning points, together with those from ordinary turning points.
This understanding of the bifurcation of a Stokes curve plays an important role
in resolving a paradox recently found in the Noumi-Yamada system, a system of
linear differential equations associated with the fourth Painleve equation.Comment: 7 pages, 4 figure
Quantification of Listeria monocytogenes in salad vegetables by MPN-PCR
The aim of this study was to assess the most probable number-polymerase chain reaction (MPN-PCR) technique for detection of Listeria monocytogenes in salad vegetables in comparison with reference EN ISO 11290-2 and Food Drug Administration Bacteriological Analytical Manual method using artifcial and naturally contaminated samples. Based on recovery of L. monocytogenes from artifcially contaminated samples, MPN-PCR showed a moderate correlation (R=0.67) between spiking concentration and microbial levels which was better than the FDA-BAM method (R=0.642) and ISO 11290-2:1998 method (R=0.655). With naturally contaminated samples, it was found that L. monocytogenes was detected in 25% of the vegetable samples using MPN-PCR; 15% of the samples by the FDA-BAM method and 8% of samples using ISO 11290-2:1998 method. Overall, MPN-PCR was found to be a rapid and reliable method that could facilitate the enumeration of L. monocytogenes in vegetables
Durability Analysis of the REIMEI Satellite Li-ion Batteries after more than 14 Years of Operation in Space
The satellite REIMEI was launched in August 2005, this is one of the first satellites to use Li-ion batteries. REIMEI is a small scientific satellite designed for carrying out aurora observations using three different cameras. The main scientific mission of the satellite ended in 2013. More than 14 years have passed, and the batteries have experienced over 78,100 charge/discharge cycles. REIMEI remains in operation with a new mission dedicated to analyzing its Li-ion battery. In this work, we present a durability analysis for the REIMEI battery based on telemetry data
Fine tuning of phosphorothioate inclusion in 2'-O-methyl oligonucleotides contributes to specific cell targeting for splice-switching modulation
Splice-switching antisense oligonucleotide- (SSO-) mediated correction of framedisrupting mutation-containing premessenger RNA (mRNA) transcripts using exon skipping is a highly promising treatment method for muscular diseases such as Duchenne muscular dystrophy (DMD). Phosphorothioate (PS) chemistry, a commonly used oligonucleotide modification, has been shown to increase the stability of and improve the pharmacokinetics of SSOs. However, the effect of PS inclusion in 2'-O-methyl SSOs (2OMe) on cellular uptake and splice switching is less well-understood. At present, we demonstrate that the modification of PS facilitates the uptake of 2OMe in H2k-mdx myoblasts. Furthermore, we found a dependency of SSO nuclear accumulation and high splice-switching activity on PS inclusion in 2OMe (2OMePS), as tested in various reporter cell lines carrying pLuc/705. Increased exon-inclusion activity was observed in muscle, neuronal, liver, and bone cell lineages via both the gymnotic uptake and lipofection of 2OMePS. Using the photoactivatable ribonucleoside-enhanced crosslinking and a subsequent proteomic approach, we identified several 2OMePS-binding proteins, which are likely to play a role in the trafficking of 2OMePS to the nucleus. Ablation of one of them, Ncl by small-interfering RNA (siRNA) enhanced 2OMePS uptake in C2C12 myoblasts and upregulated luciferase RNA splicing in the HeLa Luc/705 reporter cell line. Overall, we demonstrate that PS inclusion increases nuclear delivery and splice switching in muscle, neuronal, liver, and bone cell lineages and that the modulation of 2OMePS-binding partners may improve SSO delivery
Long-Term Survival of Resected Advanced Gastric Cancer with Hepatic and Pancreatic Invasion
A 64-year-old man was transferred to our division with a suspicion of gastric cancer. Computed tomography showed widespread irregular thickening of the stomach walls close to the liver and pancreas. Gastrointestinal fiberscopy showed a type 5 tumor in the upper to lower stomach, histologically diagnosed as tubular adenocarcinoma. Gastric cancer with hepatic and pancreatic invasion was diagnosed. Distant metastasis was not proven and complete resection was planned. At laparotomy, the tumor showed general expanding growth and invasion through the lateral segment of the liver and pancreas. Total gastrectomy and combined resection of the distal pancreas, spleen and left segment of the liver were performed. Hepatic and pancreatic invasion and lymph node metastasis were microscopically proven. Pancreatic fistula occurred postoperatively. On postoperative days 40, he was discharged. He received two cycles of adjuvant tegafur/gimeracil/oteracil chemotherapy. He has had no sign of recurrence for 7 years and 8 months
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