University of Tokyo

About: University of Tokyo is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Population & Gene. The organization has 134564 authors who have published 337567 publications receiving 10178620 citations. The organization is also known as: Todai & Universitas Tociensis.

Application of the Method of Generating Function to Radiative and Non-Radiative Transitions of a Trapped Electron in a Crystal

Abstract: Using the method of generating function, we have discussed the shape of the absorption band and the probability for non-radiative transition of a trapped electron in insulating or semiconducting crystal, especially their temperature dependence. We have thereby chosen a model for the vibrational motion of the lattice as general as possible, the normal modes for any two electronic states being different as regards not only their equilibrium positions but also the principal axes and frequencies. For non-radia­ tive transition, we have derived, in comparatively general cases, the high and low temperature behaviors of the probability which correspond to the process through activated states and the tunneling of the lattice co-ordinates, respectively. The result is applied to calculations of the probability for thermal ionization of trapped electrons (or holes) and the capture cross-section of impurities for free electrons (or holes) in non-polar semiconductors. Further, the high temperature expansion of a density matrix is used to discuss the transitions on a most general model in which lattice vibration is no longer of harmonic type. Two problems related to the degeneracy of electronic states are discussed briefly. ting or semiconducting crystal has been studied by a number of authors. The simplest but most essential explanation of the broadening effect is found in the text-book of Mott and Gurney/l where they take a one-dimensional model for the lattice configuration space to discuss the breadth of the F-absorption band. More general discussion has been given by Muto2l on a quantum mechanical basis. Inui and Uemura, aJ with one dimensional model, explained the shift of the F-absorption peak by the thermal expansion of the lattice, taking advantage of Ivey's empirical law. Quantum mechanical calculation of adiabatic potentials was first carried out by Williams4l for KCl : Tl crystal, with one dimensional model. Huang and Rhys5l discussed the shape of the F-absorption band and the thermal ionization pro­ bability of the F-electron, taking into account all the longitudinal waves of optical modes of vibration which interact strongly with the electron. Their mathematical technique, though very ingenious in itself, is confined to a single frequency model, and can hardly be genera­ lized to a many-frequency model which involves, for instance, the acoustical modes. Under these circumstances it is very desirable to have a mathematical tool which enables one to discuss radiative and non-radiative transitions on a general model of lattice vibration. One of the present authors6l developed the method of generating function several years ago,

Adjuvant sorafenib for hepatocellular carcinoma after resection or ablation (STORM): a phase 3, randomised, double-blind, placebo-controlled trial

Abstract: Summary Background There is no standard of care for adjuvant therapy for patients with hepatocellular carcinoma. This trial was designed to assess the efficacy and safety of sorafenib versus placebo as adjuvant therapy in patients with hepatocellular carcinoma after surgical resection or local ablation. Methods We undertook this phase 3, double-blind, placebo-controlled study of patients with hepatocellular carcinoma with a complete radiological response after surgical resection (n=900) or local ablation (n=214) in 202 sites (hospitals and research centres) in 28 countries. Patients were randomly assigned (1:1) to receive 400 mg oral sorafenib or placebo twice a day, for a maximum of 4 years, according to a block randomisation scheme (block size of four) using an interactive voice-response system. Patients were stratified by curative treatment, geography, Child-Pugh status, and recurrence risk. The primary outcome was recurrence-free survival assessed after database cut-off on Nov 29, 2013. We analysed efficacy in the intention-to-treat population and safety in randomly assigned patients receiving at least one study dose. The final analysis is reported. This study is registered with ClinicalTrials.gov, number NCT00692770. Findings We screened 1602 patients between Aug 15, 2008, and Nov 17, 2010, and randomly assigned 1114 patients. Of 556 patients in the sorafenib group, 553 (>99%) received the study treatment and 471 (85%) terminated treatment. Of 558 patients in the placebo group, 554 (99%) received the study treatment and 447 (80%) terminated treatment. Median duration of treatment and mean daily dose were 12·5 months (IQR 2·6–35·8) and 577 mg per day (SD 212·8) for sorafenib, compared with 22·2 months (8·1–38·8) and 778·0 mg per day (79·8) for placebo. Dose modification was reported for 497 (89%) of 559 patients in the sorafenib group and 206 (38%) of 548 patients in the placebo group. At final analysis, 464 recurrence-free survival events had occurred (270 in the placebo group and 194 in the sorafenib group). Median follow-up for recurrence-free survival was 8·5 months (IQR 2·9–19·5) in the sorafenib group and 8·4 months (2·9–19·8) in the placebo group. We noted no difference in median recurrence-free survival between the two groups (33·3 months in the sorafenib group vs 33·7 months in the placebo group; hazard ratio [HR] 0·940; 95% CI 0·780–1·134; one-sided p=0·26). The most common grade 3 or 4 adverse events were hand-foot skin reaction (154 [28%] of 559 patients in the sorafenib group vs four [ vs five [ Interpretation Our data indicate that sorafenib is not an effective intervention in the adjuvant setting for hepatocellular carcinoma following resection or ablation. Funding Bayer HealthCare Pharmaceuticals and Onyx Pharmaceuticals.

Extensive feature detection of N-terminal protein sorting signals.

Abstract: Motivation: The prediction of localization sites of various proteins is an important and challenging problem in the field of molecular biology. TargetP, by Emanuelsson et al. (J. Mol. Biol., 300, 1005‐1016, 2000) is a neural network based system which is currently the best predictor in the literature for N-terminal sorting signals. One drawback of neural networks, however, is that it is generally difficult to understand and interpret how and why they make such predictions. In this paper, we aim to generate simple and interpretable rules as predictors, and still achieve a practical prediction accuracy. We adopt an approach which consists of an extensive search for simple rules and various attributes which is partially guided by human intuition. Results: We have succeeded in finding rules whose prediction accuracies come close to that of TargetP, while still retaining a very simple and interpretable form. We also discuss and interpret the discovered rules. Availability: An (experimental) web service using rules obtained by our method is provided at http:

The Arabidopsis ERECTA gene encodes a putative receptor protein kinase with extracellular leucine-rich repeats.

Abstract: Arabidopsis Landsberg erecta is one of the most popular ecotypes and is used widely for both molecular and genetic studies. It harbors the erecta (er) mutation, which confers a compact inflorescence, blunt fruits, and short petioles. We have identified five er mutant alleles from ecotypes Columbia and Wassilewskija. Phenotypic characterization of the mutant alleles suggests a role for the ER gene in regulating the shape of organs originating from the shoot apical meristem. We cloned the ER gene, and here, we report that it encodes a putative receptor protein kinases. The deduced ER protein contains a cytoplasmic protein kinase catalytic domain, a transmembrane region, and an extracellular domain consisting of leucine-rich repeats, which are thought to interact with other macromolecules. Our results suggest that cell-cell communication mediated by a receptor kinase has an important role in plant morphogenesis.

Rotation Curves of Spiral Galaxies

Abstract: Rotation curves of spiral galaxies are the major tool for determining the distribution of mass in spiral galaxies. They provide fundamental information for understanding the dynamics, evolution and formation of spiral galaxies. We describe various methods to derive rotation curves, and review the results obtained. We discuss the basic characteristics of observed rotation curves in relation to various galaxy properties, such as Hubble type, structure, activity, and environment.