Surface density of states and topological edge states in non-centrosymmetric superconductors

We study Andreev bound state (ABS) and surface density of state (SDOS) of non-centrosymmetric superconductor where spin-singlet $d$-wave pairing mixes with spin-triplet $p$ (or $f)$-wave one by spin-orbit coupling. For $d_{xy} + p$-wave pairing, ABS appears as a zero energy state. The present ABS is a Majorana edge mode preserving the time reversal symmetry. We calculate topological invariant number and discuss the relevance to a single Majorana edge mode. In the presence of the Majorana edge mode, the SDOS depends strongly on the direction of the Zeeman field.Comment: 10 pages, 15 figure

CRISPR/Cas9-based generation of knockdown mice by intronic insertion of artificial microRNA using longer single-stranded DNA.

Knockdown mouse models, where gene dosages can be modulated, provide valuable insights into gene function. Typically, such models are generated by embryonic stem (ES) cell-based targeted insertion, or pronuclear injection, of the knockdown expression cassette. However, these methods are associated with laborious and time-consuming steps, such as the generation of large constructs with elements needed for expression of a functional RNAi-cassette, ES-cell handling, or screening for mice with the desired knockdown effect. Here, we demonstrate that reliable knockdown models can be generated by targeted insertion of artificial microRNA (amiRNA) sequences into a specific locus in the genome [such as intronic regions of endogenous eukaryotic translation elongation factor 2 (eEF-2) gene] using the Clustered Regularly Interspaced Short Palindromic Repeats/Crispr associated 9 (CRISPR/Cas9) system. We used in vitro synthesized single-stranded DNAs (about 0.5-kb long) that code for amiRNA sequences as repair templates in CRISPR/Cas9 mutagenesis. Using this approach we demonstrate that amiRNA cassettes against exogenous (eGFP) or endogenous [orthodenticle homeobox 2 (Otx2)] genes can be efficiently targeted to a predetermined locus in the genome and result in knockdown of gene expression. We also provide a strategy to establish conditional knockdown models with this method

Developmental changes and organelle biogenesis in the reproductive organs of thermogenic skunk cabbage (Symplocarpus renifolius)

Sex-dependent thermogenesis during reproductive organ development in the inflorescence is a characteristic feature of some of the protogynous arum species. One such plant, skunk cabbage (Symplocarpus renifolius), can produce massive heat during the female stage but not during the subsequent male stage in which the stamen completes development, the anthers dehisce, and pollen is released. Unlike other thermogenic species, skunk cabbage belongs to the bisexual flower group. Although recent studies have identified the spadix as the thermogenic organ, it remains unclear how individual tissues or intracellular structures are involved in thermogenesis. In this study, reproductive organ development and organelle biogenesis were examined during the transition from the female to the male stage. During the female stage, the stamens exhibit extensive structural changes including changes in organelle structure and density. They accumulate high levels of mitochondrial proteins, including possible thermogenic factors, alternative oxidase, and uncoupling protein. By contrast, the petals and pistils do not undergo extensive changes during the female stage. However, they contain a larger number of mitochondria than during the male stage in which they develop large cytoplasmic vacuoles. Comparison between female and male spadices suggests that mitochondrial number rather than their level of activity correlates with thermogenesis. Their spadices, even in the male, contain a larger amount of mitochondria that had greater oxygen consumption, compared with non-thermogenic plants. Taken together, our data suggest that the extensive maturation process in stamens produces massive heat through increased metabolic activities. The possible mechanisms by which petal and pistil metabolism may affect thermogenesis are also discussed

Topology of Andreev Bound States with Flat Dispersion

A theory of dispersionless Andreev bound states on surfaces of time-reversal invariant unconventional superconductors is presented. The generalized criterion for the dispersionless Andreev bound state is derived from the bulk-edge correspondence, and the chiral spin structure of the dispersionless Andreev bound states is argued from which the Andreev bound state is stabilized. Then we summarize the criterion in a form of index theorems. The index theorems are proved in a general framework to certify the bulk-edge correspondence. As concrete examples, we discuss (i) dxy-wave superconductor (ii) px-wave superconductor, and (iii) noncentrosymmetric superconductors. In the last example, we find a peculiar time-reversal invariant Majorana fermion. The time-reversal invariant Majorana fermion shows an unusual response to the Zeeman magnetic field, which can be used to identify it experimentally.Comment: 56 pages, 11 figures, references are adde

Clonal Diversity of the Expression of MHC Class I Antigens. and Endogenous Retroviral Antigens on the Oncogene-Induced Cell Transformation of BALB3T3 Cells-Different Regulatory Mechanisms for the Expression of Antigens

The effect of the activated oncogene transfection on the expression of MHC class I H-2Kd, Dd and Ld and endogenous retroviral antigens was analyzed on 21 clones independently derived from the same parental BALB3T3. These clones were obtained by transfecting BALB3T3 with EJ-ras, PyMT, c-myc, and v-src oncogenes. The expression of MHC class I H-2Ld and H-2Kd antigens was reduced in clones with high anchorage independent growth potential. However, clones with low or no anchorage independent growth potential displayed almost the same degree of expression as parental BALB3T3. The H-2Dd antigen was for the most part conserved. The reduced expression of H-2Kd antigen was com-pletely restored by IFN treatment, whereas that of H-2Ld antigen was only par-tially restored. Meanwhile, MuLV and MMTV antigens were expressed on parental BALB3T3. These antigens was down-modulated in all of the EJ-ras and in one of the v-src-transfected clones. However, all the PyMT-transfected clones expressed the antigens as much as parental BALB3T3 even in the clones with high anchorage independent growth potential. These data suggest that the MHC class I antigen expression is modulated with the transforming process of cells, whereas the endogenous retroviral antigen expression might be dependent upon the transfected oncogenes rather than the transforming phenotype of the cells

Analysing features of Japanese splogs and characteristics of keywords

This paper focuses on analyzing (Japanese) splogs based on various characteristics of keywords contained in them. We estimate the behavior of spammers when creating splogs from other sources by analyzing the characteristics of key-words contained in splogs. Since splogs often cause noises in word occurrence statistics in the blogosphere, we assume that we can efficiently (manually) collect splogs by sampling blog homepages containing keywords of a certain type on the date with its most frequent occurrence. We manually exam-ine various features of collected blog homepages regarding whether their text content is excerpt from other sources or not, as well as whether they display affiliate advertisement or out-going links to affiliated sites. Among various infor-mative results, it is important to note that more than half of the collected splogs are created by a very small number of spammers

Theory of Macroscopic Quantum Tunneling in High-T_c c-Axis Josephson Junctions

We study macroscopic quantum tunneling (MQT) in c-axis twist Josephson junctions made of high-T_c superconductors in order to clarify the influence of the anisotropic order parameter symmetry (OPS) on MQT. The dependence of the MQT rate on the twist angle $\gamma$ about the c-axis is calculated by using the functional integral and the bounce method. Due to the d-wave OPS, the $\gamma$ dependence of standard deviation of the switching current distribution and the crossover temperature from thermal activation to MQT are found to be given by $\cos2\gamma$ and $\sqrt{\cos2\gamma}$, respectively. We also show that a dissipative effect resulting from the nodal quasiparticle excitation on MQT is negligibly small, which is consistent with recent MQT experiments using Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8 + \delta}$ intrinsic junctions. These results indicate that MQT in c-axis twist junctions becomes a useful experimental tool for testing the OPS of high-T_c materials at low temperature, and suggest high potential of such junctions for qubit applications.Comment: 15 pages, 8 figures, 1 tabl