Observation of finite excess noise in the voltage-biased quantum Hall regime as a precursor for breakdown

We performed noise measurements in a two-dimensional electron gas to investigate the nonequilibrium quantum Hall effect (QHE) state. While excess noise is perfectly suppressed around the zero-biased QHE state reflecting the dissipationless electron transport of the QHE state, considerable finite excess noise is observed in the breakdown regime of the QHE. The noise temperature deduced from the excess noise is found to be of the same order as the energy gap between the highest occupied Landau level and the lowest empty one. Moreover, unexpected finite excess noise is observed at a finite source-drain bias voltagesmaller than the onset voltage of the QHE breakdown, which indicates finite dissipation in the QHE state and may be related to the prebreakdown of the QHE.Comment: 8 pages, 8 figure

Neural Structure Fields with Application to Crystal Structure Autoencoders

Representing crystal structures of materials to facilitate determining them via neural networks is crucial for enabling machine-learning applications involving crystal structure estimation. Among these applications, the inverse design of materials can contribute to next-generation methods that explore materials with desired properties without relying on luck or serendipity. We propose neural structure fields (NeSF) as an accurate and practical approach for representing crystal structures using neural networks. Inspired by the concepts of vector fields in physics and implicit neural representations in computer vision, the proposed NeSF considers a crystal structure as a continuous field rather than as a discrete set of atoms. Unlike existing grid-based discretized spatial representations, the NeSF overcomes the tradeoff between spatial resolution and computational complexity and can represent any crystal structure. To evaluate the NeSF, we propose an autoencoder of crystal structures that can recover various crystal structures, such as those of perovskite structure materials and cuprate superconductors. Extensive quantitative results demonstrate the superior performance of the NeSF compared with the existing grid-based approach.Comment: 16 pages , 6 figures. 13 pages Supplementary Informatio

Comparison of Conventional 2D CC (Cranio-Caudal) + MLO (Medio-Lateral Oblique) Bi-Directional Photography and 2D-MLO + DBT-MLO (Digital Breast Tomosynthesis) in Mammography Examination

Introduction: Mammography (MMG) is an excellent examination for breast cancer detection and is widely used in both screening and clinical practice. However, the breast thickness and background the concentration of the mammary gland is large among individuals, and the mammary gland and cancer may overlap and it may not be possible to point out a lesion. In recent years, digital breast tomosynthesis (hereinafter referred to as DBT) has been introduced to solve these problems, and its usefulness has been reported in clinical practice. Therefore, in anticipation of a higher cancer detection rate etc., we compared the conventional 2D CC + MLO 2-way MMG examination with 2DMLO + DBTMLO 2-way MMG examination.Materials and Methods: The combination of 2D CC + MLO and 2DMLO + DBTMLO was read for 95 cases of breast cancer taking 2D CC and MLO and DBT MLO from May 2016 to October 2017. It was judged that the category 3 or more required detailed examination, cancer detection, and cancer detection rates were compared. Subjects were 28 to 87 years of age (median: 55 years), breast composition: high concentration 15.8% (15 cases), heterogeneous high concentration 47.4% (45 cases), mammary gland 28.4% (27 cases), Fatty was 8.4% (8 cases).Results: The cancer detection rate was 87% for the 2D CC + MLO combination and 94% for the 2DMLO + DBTMLO combination in 95 cases of breast cancer. The interpretation time was 95 minutes for the 2D CC + MLO combination and 110 minutes for the 2DMLO + DBTMLO combination.The breast cancer detected only by the combination of 2D CC + MLO was scattered in 1 case and was classified as Category 3 by FAD. Breast cancer detected only by the combination of 2DMLO + DBTMLO: 8 cases with uneven distribution of breast composition, 3 cases with scattered mammary gland, 3 cases with 5 cases with disordered construction, Category 4 with 3 cases with FAD was.Conclusion: Both 2D CC + MLO combination and 2DMLO + DBTMLO combination are considered useful for screening MMG examination. In particular, we would like to consider the introduction to medical examinations for the addition of MMG in DBT, but the issue of the amount of image information, the problem of exposure to radiation, the direction of imaging, the establishment of interpretation methods etc. are future issues

Fyn tyrosine kinase is a downstream mediator of Rho/PRK2 function in keratinocyte cell–cell adhesion

The Rho GTPase and Fyn tyrosine kinase have been implicated previously in positive control of keratinocyte cell–cell adhesion. Here, we show that Rho and Fyn operate along the same signaling pathway. Endogenous Rho activity increases in differentiating keratinocytes and is required for both Fyn kinase activation and increased tyrosine phosphorylation of β- and γ-catenin, which is associated with the establishment of keratinocyte cell–cell adhesion. Conversely, expression of constitutive active Rho is sufficient to promote cell–cell adhesion through a tyrosine kinase- and Fyn-dependent mechanism, trigger Fyn kinase activation, and induce tyrosine phosphorylation of β- and γ-catenin and p120ctn. The positive effects of activated Rho on cell–cell adhesion are not induced by an activated Rho mutant with defective binding to the serine/threonine PRK2/PKN kinases. Endogenous PRK2 kinase activity increases with keratinocyte differentiation, and, like activated Rho, increased PRK2 activity promotes keratinocyte cell–cell adhesion and induces tyrosine phosphorylation of β- and γ-catenin and Fyn kinase activation. Thus, these findings reveal a novel role of Fyn as a downstream mediator of Rho in control of keratinocyte cell–cell adhesion and implicate the PRK2 kinase, a direct Rho effector, as a link between Rho and Fyn activation

Activation of Protein Kinase B Induced by H2O2 and Heat Shock through Distinct Mechanisms Dependent and Independent of Phosphatidylinositol 3-Kinase

Protein kinase B (PKB) is a downstream target of phosphatidylinositol (PI) 3-kinase in the signaling pathway of growth factors, and is activated by cellular stress such as H2O2 and heat shock. To study the mechanism of the stress-induced activation of PKB, PI 3-kinase products were measured in stress-stimulated cells. Both PI 3, 4-bisphosphate and PI 3, 4, 5-trisphosphate increased in H2O2 -treated cells, and the elevation of these phospholipids and activation of PKB were concurrently blocked by wortmannin, a potent inhibitor of PI 3-kinase. In heat-shocked cells, the level of PI 3, 4-bisphosphate did not change while that of PI 3, 4, 5-trisphosphate increased slightly, and an association between PKB molecules was observed. Two active PKB fractions, presumably monomeric and oligomeric forms, were resolved from heat-shocked cells by gel filtration column chromatography. Activation of the former was suppressed by pretreatment with wortmannin, whereas the generation and activation of the latter were not blocked by the PI 3-kinase inhibitor. Only the monomeric form, but not the oligomeric form, was recovered from H2O2 -treated cells, and its activation was prevented by wortmannin. These results indicate that PKB is activated by two distinct mechanisms that are dependent and independent of PI 3-kinase in stress-stimulated cell

Fragmentation of Protein Kinase N (PKN) in the Hydrocephalic Rat Brain

PKN (protein kinase N; also called protein kinase C-related kinase (PRK-1)), is a serine/threonine protein kinase that is ubiquitously expressed in several organs, including the brain. PKN has a molecular mass of 120 kDa and has two domains, a regulatory and a catalytic domain, in its amino-terminals and carboxyl-terminus, respectively. Although the role of PKN has not been fully elucidated, previous studies have revealed that PKN is cleaved to a constitutively active catalytic fragment of 55 kDa in response to apoptotic signals. Hydrocephalus is a pathological condition caused by insufficient cerebrospinal fluid (CSF) circulation and subsequent excess of CSF in the brain. In this study, in order to elucidate the role of PKN in the pathophysiology of hydrocephalus, we examined PKN fragmentation in hydrocephalic model rats

Double strand break repair by capture of retrotransposon sequences and reverse-transcribed spliced mRNA sequences in mouse zygotes

Ono, R., Ishii, M., Fujihara, Y. et al. Double strand break repair by capture of retrotransposon sequences and reverse-transcribed spliced mRNA sequences in mouse zygotes. Sci Rep 5, 12281 (2015). https://doi.org/10.1038/srep1228