Ion-Ion Correlation Effect on the Neutrino-Nucleus Scattering in Supernova Cores

We calculate the ion-ion correlation effect on the neutrino-nucleus scattering in supernova cores, which is an important opacity source for the neutrinos and plays a vital role in the supernova explosion. In order to calculate the ion-ion correlation effect we use the results of the improved hypernetted-chain method calculations of the classical one-component plasma. As in the preceding studies on this effect, we find a dramatic decrease of the effective neutrino-nucleus scattering cross section for relatively low energy neutrinos with E < 20MeV. As a matter of fact, our calculation shows a much more dramatic reduction of the effective neutrino-nucleus scattering cross section for the low energy neutrinos with E < 10MeV than the results of Horowitz. Therefore, the ion-ion correlation effect will be more important than has hitherto been recognized. We present an accurate analytic fitting formula that summarizes our numerical results. This fitting formula will facilitate the application of the present results to the supernova explosion simulations.Comment: 10 pages, 2 figures, 1 subroutine, published in ApJ 611, 1041-1044 (2004

Critical Differences in Magnitude and Duration of N-methyl-D-aspartate (NMDA) Receptor Activation between Long-term Potentiation (LTP) and Long-term Depression (LTD) Induction

The induction of both long-term potentiation (LTP) and long-term depression (LTD) in the hippocampal CA1 region is triggered by the activation of N-methyl-D-aspartate (NMDA) receptors and the subsequent postsynaptic intracellular Ca2+ increase. However, how NMDA receptor activation differs between LTP and LTD induction is unclear. In the present study, we examined the eff ects of the magnitude and duration of NMDA receptor activation on the induction of LTP and LTD. Partial blockage of NMDA receptors by a low concentration of aminophosphonovaleric acid (APV)(2 &#956;M) prevented the induction of LTP, but not LTD. In contrast, a high concentration of APV(25 &#956;M) blocked both LTP and LTD. Tetanus stimulation-induced LTP was impaired when hippocampal slices were given the tetanus stimulation for more than 5 min. Under partial blockage of NMDA receptors, the prolonged-tetanus stimulation induced LTD but not LTP. This phenomenon was mimicked by the application of glutamate to the slices. Finally, LTD induced by prolonged activation of NMDA receptors was not aff ected by inhibition of the desensitization of &#945;-amino-3-hydroxy-5 methylisoxazole-4-propionic acid (AMPA) receptors. These results suggest that critical diff erences exist between the induction of LTP and that of LTD in terms of both the magnitude and the duration of NMDA receptor activation. The duration of the increase in intracellular Ca2+ concentration may be critical for determining whether LTP or LTD induction occurs.</p

Nonautonomous differential equations and Lipschitz evolution operators in Banach spaces

A new class of Lipschitz evolution operators is introduced and a characterization of continuous in nitesimal generators of such evolution operators is given. It is shown that a continuous mapping A from a subset Ω of [a; b) X into X, where [a; b) is a real half-open interval and X is a real Banach space, is the in nitesimal generator of a Lipschitz evolution operator if and only if it satis es a sub-tangential condition, a general type of quasi-dissipative condition with respect to a metric-like functional and a connectedness condition. An application of the results to the initial value problem for the quasilinear wave equation with dissipation is also given

Enhancement of Resonant Thermonuclear Reaction Rates in Extremely Dense Stellar Plasmas

The enhancement factor of the resonant thermonuclear reaction rates is calculated for the extremely dense stellar plasmas in the liquid phase. In order to calculate the enhancement factor we use the screening potential which is deduced from the numerical experiment of the classical one-component plasma. It is found that the enhancement is tremendous for white dwarf densities if the ^{12}C + ^{12}C fusion cross sections show resonant behavior in the astrophysical energy range. We summarize our numerical results by accurate analytic fitting formulae.Comment: 13 pages, 3 figures, accepted for publication in ApJ, replaced with revised versio

2-Methylthio Conversion of N6-Isopentenyladenosine in Mitochondrial tRNAs by CDK5RAP1 Promotes the Maintenance of Glioma-Initiating Cells

2-Methylthio-N-6-isopentenyl modification of adenosine (ms(2)i(6)A) is an evolutionally conserved modification found in mitochondrial (mt)-tRNAs. Cdk5 regulatory subunit-associated protein 1 (CDK5RAP1) specifically converts N6-isopentenyladenosine (i(6)A) to ms(2)i(6)A at position A37 of four mt-DNA-encoded tRNAs, and the modification regulates efficient mitochondrial translation and energy metabolism in mammals. Here, we report that the ms 2 conversion mediated by CDK5RAP1 in mt-tRNAs is required to sustain glioma-initiating cell (GIC)-related traits. CDK5RAP1 maintained the self-renewal capacity, undifferentiated state, and tumorigenic potential of GICs. This regulation was not related to the translational control of mt-proteins. CDK5RAP1 abrogated the antitumor effect of i(6)A by converting i(6)A to ms (2)i(6) A and protected GICs from excessive autophagy triggered by i(6)A. The elevated activity of CDK5RAP1 contributed to the amelioration of the tumor-suppressive effect of i(6)A and promoted GIC maintenance. This work demonstrates that CDK5RAP1 is crucial for the detoxification of endogenous i(6)A and that GICs readily utilize this mechanism for survival

Screening Corrections to the Electron Capture Rates in Dense Stars by the Relativistically Degenerate Electron Liquid

We calculate the screening corrections to the electron capture rates in dense stars by the relativistically degenerate electron liquid. In order to calculate the screening corrections we adopt the linear response theory which is widely used in the field of solid state physics and liquid metal physics. In particular, we use the longitudinal dielectric function for the relativistically degenerate electron liquid derived by Jancovici. We calculate the screening potential at the position of the nucleus. By using this screening potential one can calculate the screening corrections to the electron capture rates. We will present accurate analytic fitting formulae which summarize our numerical results. These fitting formulae will facilitate the application of the present results. The screening corrections to the electron capture rates are typically a few percent.Comment: uses AAS LaTeX macro package (Ver. 5.0), 8 pages, 2 tables, 4 figures, 2 subroutines, published in ApJ 579, 380-385 (2002

Learning of thoracoscopic radical esophagectomy: How can the learning curve be made short and flat?

金沢大学附属病院胃腸外科Attainment of proficiency in video-assisted thoracoscopic radical esophagectomy (VATS) for thoracic esophageal cancer requires much experience. We have mastered this procedure safely under the direction of an experienced surgeon. After adoption of the procedure, the educated surgeon directed induction of this surgical procedure at another institution. We evaluated the efficacy of instruction during the induction period by comparing the results at the two institutions in which VATS had been newly induced. We defined the induction period as the time from the beginning of VATS to the time when the last instruction was carried out. From January 2003 to December 2007, 53 patients were candidates for VATS at Kanazawa University (institution 1). Of these, 46 patients underwent curative VATS by a single operator. We divided this period into three parts: the induction period of VATS, post-induction period, and proficient period when the educated surgeon of institution 1 directed the procedure at Maebashi Red Cross Hospital (institution 2). At institution 1, 12 VATS were scheduled, and nine procedures (75%) (group A) including eight instructions were completed during the induction period (from January 2003 to August 2004). Thereafter, VATS was performed without instruction. In the post-induction period, nine VATS were scheduled, and eight procedures (88.8%) (group B) were completed from September 2004 to August 2005. Subsequently, 32 VATS were scheduled, and 29 procedures (90.6%) (group C) were completed during the proficient period (from September 2005 to December 2007). The surgeon at Maebashi Red Cross Hospital (institution 2) started to perform VATS under the direction of the surgeon who had been educated at institution 1 from September 2005. VATS was completed in 13 (76.4%) (group D) of 17 cases by a single surgeon including seven instructions during the induction period at institution 2 from September 2005 to December 2007. No lethal complication occurred during the induction period at both institutions. We compared the results of VATS among four groups from the two institutions. There were no differences in the background and clinicopathological features among the four groups. The number of dissected lymph nodes and amount of thoracic blood loss were similar in the four groups (35 [22-52] vs 41 [26-53] vs 32 [17-69] vs 29 [17-42] nodes, P = 0.139, and 170 [90-380] vs 275 [130-550] vs 220 [10-660] vs 210 [75-543] g, P = 0.373, respectively). There was no difference in the duration of the thoracic procedure during the induction period at the two institutions. However, the duration of the procedure was significantly shorter in the proficient period of institution 1 (group C: 266 [195-555] minutes) than in the induction period of both institutions (group A: 350 [280-448] minutes [P = 0.005] and group D: 345 [270-420] mL [P = 0.002]). There were no surgery-related deaths in any of the groups. The incidence of postoperative complications did not differ among the four groups. Thoracoscopic radical esophagectomy can be mastered quickly and safely with a flat learning curve under the direction of an experienced surgeon. The educated surgeon can instruct surgeons at another institution on how to perform thoracoscopic esophagectomy. The operation time of thoracoscopic surgery is shortened by experience. © 2010 Copyright the Authors. Journal compilation © 2010, Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus

The Effect of Neutrophil Elastase Inhibitor in Hepatectomy with Ischemia in Dogs

学位記番号:医博乙123