Topological carbon allotropes: paradigm shift for materials innovation

Topology is a central concept of mathematics, which allows us to distinguish two isolated rings with linked ones. In material science, researchers discovered topologically different carbon allotropes in a form of a cage, a tube, and a sheet, which have unique translational and rotational symmetries, described by a crystallographic group theory, and the atoms are arranged at specific rigid positions in 3-dimensional ($D$) space. However, topological orders must be robust against deformations, so that we can make completely different families of topological materials. Here we propose various topological structures such as knots and links using covalent $\sigma$ bonds of carbon atoms, while allowing various topologically equivalent arrangements using weak $\pi$ bonds. By extending this idea, we invented a new 3D carbon allotrope, Hopfene, which has periodic arrays of Hopf-links to knit horizontal Graphene sheets into vertical ones without connecting by $\sigma$ bonds.Comment: 19 pages, 14 figure

Vascular Lesions Produced by Transient Renal Ischemia

It has been clarified by the studies of our laboratory that the renal cortical extract of normal rats and experimentally hypertensive rats contain vascular injurious factors in addition to pressor substances. For the purpose of demonstrating this evidence in vivo, observations were made mostly of mesenteric and pancreatic vessels upon performing unilateral nephrectomy and contralateral renal arterial and ureteral ligations and releasing the arterial ligation after 2 hours and the ureteral ligation after 24 hours. As the result of transient renal ischemia, abnormalities of electrolytes, serum blood urea nitrogen and creatinine were recognized but these were gradually recovered. For eliminating pressor factors, rats without significant increase of blood pressure were used for the study. One day after the surgery, fibrinoid degeneration appeared in the media of arterioles and small arteries. This change developed with time into angiitis and panarteritis like lesions on the seventh day after the surgery. These vascular lesions were basically the same as those caused by the renal cortical extract. Accordingly, the vascular lesions resulting from transient renal ischemia were deemed to be caused by renal vascular injurious substances in vivo

Stimulated Raman amplification in Ga As/Al As intermixed superlattices

The enhancement of stimulated Raman scattering (SRS) with a Ga As / Al As intermixed superlattice that works as a χ ( 3 ) -quasi-phase-matched structure is studied, where such Kerr-induced effects as four-wave mixing (FWM), self-phase-modulation (SPM), cross-phase-modulation (XPM), and two-photon absorption (TPA) are included. In particular, the efficiency of anti-Stokes generation is enhanced here; anti-Stokes generation inherently has an extremely small efficiency due to a phase mismatch in the interaction of the pump, Stokes, and anti-Stokes waves (while the efficiency of Stokes generation is sufficiently large because of no such phase mismatch). The superlattice enhances the anti-Stokes efficiency up to the order of 10 3 when compared with that without the superlattice, particularly at a small pump intensity. In this enhancement, it is seen that there is an efficiency boost via simultaneous FWM. In this situation, it is shown how much SPM and XPM degrade the efficiency enhancement. Furthermore, an optimal superlattice length is identified that provides the highest efficiency. The degradation of the efficiency at the optimized length due to TPA is also analyzed. Finally, to gain more anti-Stokes efficiency (or control the sizes of the Stokes and anti-Stokes efficiencies), a photonic-band-gap cavity structure is proposed

Network Features and Pathway Analyses of a Signal Transduction Cascade

The scale-free and small-world network models reflect the functional units of networks. However, when we investigated the network properties of a signaling pathway using these models, no significant differences were found between the original undirected graphs and the graphs in which inactive proteins were eliminated from the gene expression data. We analyzed signaling networks by focusing on those pathways that best reflected cellular function. Therefore, our analysis of pathways started from the ligands and progressed to transcription factors and cytoskeletal proteins. We employed the Python module to assess the target network. This involved comparing the original and restricted signaling cascades as a directed graph using microarray gene expression profiles of late onset Alzheimer's disease. The most commonly used method of shortest-path analysis neglects to consider the influences of alternative pathways that can affect the activation of transcription factors or cytoskeletal proteins. We therefore introduced included k-shortest paths and k-cycles in our network analysis using the Python modules, which allowed us to attain a reasonable computational time and identify k-shortest paths. This technique reflected results found in vivo and identified pathways not found when shortest path or degree analysis was applied. Our module enabled us to comprehensively analyse the characteristics of biomolecular networks and also enabled analysis of the effects of diseases considering the feedback loop and feedforward loop control structures as an alternative path