One-electron states and interband optical absorption in single-wall carbon nanotubes

Explicit expressions for the wave functions and dispersion equation for the band p - electrons in single-wall carbon nanotubes are obtained within the method of zero-range potentials. They are then used to investigate the absorption spectrum of polarized light caused by direct interband transitions in isolated nanotubes. It is shown that, at least, under the above approximations, the circular dichroism is absent in chiral nanotubes for the light wave propagating along the tube axis. The results obtained are compared with those calculated in a similar way for a graphite plane.Comment: 16 pages, 8 figures, 1 tabl

Contribution of the cyclic nucleotide gated channel subunit, CNG-3, to olfactory plasticity in Caenorhabditis elegans.

In Caenorhabditis elegans, the AWC neurons are thought to deploy a cGMP signaling cascade in the detection of and response to AWC sensed odors. Prolonged exposure to an AWC sensed odor in the absence of food leads to reversible decreases in the animal's attraction to that odor. This adaptation exhibits two stages referred to as short-term and long-term adaptation. Previously, the protein kinase G (PKG), EGL-4/PKG-1, was shown necessary for both stages of adaptation and phosphorylation of its target, the beta-type cyclic nucleotide gated (CNG) channel subunit, TAX-2, was implicated in the short term stage. Here we uncover a novel role for the CNG channel subunit, CNG-3, in short term adaptation. We demonstrate that CNG-3 is required in the AWC for adaptation to short (thirty minute) exposures of odor, and contains a candidate PKG phosphorylation site required to tune odor sensitivity. We also provide in vivo data suggesting that CNG-3 forms a complex with both TAX-2 and TAX-4 CNG channel subunits in AWC. Finally, we examine the physiology of different CNG channel subunit combinations

ESSVCS: an enriched secret sharing visual cryptography

Visual Cryptography (VC) is a powerful technique that combines the notions of perfect ciphers and secret sharing in cryptography with that of raster graphics. A binary image can be divided into shares that are able to be stacked together so as to approximately recover the original image. VC is a unique technique in the sense that the encrypted message can be decrypted directly by the Human Visual System (HVS). The distinguishing characteristic of VC is the ability of secret restoration without the use of computation. However because of restrictions of the HVS, pixel expansion and alignment problems, a VC scheme perhaps can only be applied to share a small size of secret image. In this paper, we present an Enriched Secret Sharing Visual Cryptography Scheme (ESSVCS) to let the VC shares carry more secrets, the technique is to use cypher output of private-key systems as the input random numbers of VC scheme, meanwhile the encryption key could be shared, the shared keys could be associated with the VC shares. After this operation, VC scheme and secret sharing scheme are merged with the private-key system. Under this design, we implement a (k; t; n)-VC scheme. Compared to those existing schemes, our scheme could greatly enhance the ability of current VC schemes and could cope with pretty rich secrets

Non-homologous end-joining pathway associated with occurrence of myocardial infarction: gene set analysis of genome-wide association study data

<p>Purpose: DNA repair deficiencies have been postulated to play a role in the development and progression of cardiovascular disease (CVD). The hypothesis is that DNA damage accumulating with age may induce cell death, which promotes formation of unstable plaques. Defects in DNA repair mechanisms may therefore increase the risk of CVD events. We examined whether the joints effect of common genetic variants in 5 DNA repair pathways may influence the risk of CVD events.</p> <p>Methods: The PLINK set-based test was used to examine the association to myocardial infarction (MI) of the DNA repair pathway in GWAS data of 866 subjects of the GENetic DEterminants of Restenosis (GENDER) study and 5,244 subjects of the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) study. We included the main DNA repair pathways (base excision repair, nucleotide excision repair, mismatch repair, homologous recombination and non-homologous end-joining (NHEJ)) in the analysis.</p> <p>Results: The NHEJ pathway was associated with the occurrence of MI in both GENDER (P = 0.0083) and PROSPER (P = 0.014). This association was mainly driven by genetic variation in the MRE11A gene (PGENDER = 0.0001 and PPROSPER = 0.002). The homologous recombination pathway was associated with MI in GENDER only (P = 0.011), for the other pathways no associations were observed.</p> <p>Conclusion: This is the first study analyzing the joint effect of common genetic variation in DNA repair pathways and the risk of CVD events, demonstrating an association between the NHEJ pathway and MI in 2 different cohorts.</p&gt

Metastable liquid-liquid phase transition in a single-component system with only one crystal phase and no density anomaly

We investigate the phase behavior of a single-component system in 3 dimensions with spherically-symmetric, pairwise-additive, soft-core interactions with an attractive well at a long distance, a repulsive soft-core shoulder at an intermediate distance, and a hard-core repulsion at a short distance, similar to potentials used to describe liquid systems such as colloids, protein solutions, or liquid metals. We showed [Nature {\bf 409}, 692 (2001)] that, even with no evidences of the density anomaly, the phase diagram has two first-order fluid-fluid phase transitions, one ending in a gas--low-density liquid (LDL) critical point, and the other in a gas--high-density liquid (HDL) critical point, with a LDL-HDL phase transition at low temperatures. Here we use integral equation calculations to explore the 3-parameter space of the soft-core potential and we perform molecular dynamics simulations in the interesting region of parameters. For the equilibrium phase diagram we analyze the structure of the crystal phase and find that, within the considered range of densities, the structure is independent of the density. Then, we analyze in detail the fluid metastable phases and, by explicit thermodynamic calculation in the supercooled phase, we show the absence of the density anomaly. We suggest that this absence is related to the presence of only one stable crystal structure.Comment: 15 pages, 21 figure

G protein-coupled receptor kinase 5 mediates Tazarotene-induced gene 1-induced growth suppression of human colon cancer cells

<p>Abstract</p> <p>Background</p> <p>Tazarotene-induced gene 1 (TIG1) is a retinoid-inducible type II tumour suppressor gene. The B isoform of TIG1 (TIG1B) inhibits growth and invasion of cancer cells. Expression of TIG1B is frequently downregulated in various cancer tissues; however, the expression and activities of the TIG1A isoform are yet to be reported. Therefore, this study investigated the effects of the TIG1A and TIG1B isoforms on cell growth and gene expression profiles using colon cancer cells.</p> <p>Methods</p> <p>TIG1A and TIG1B stable clones derived from HCT116 and SW620 colon cancer cells were established using the GeneSwitch system; TIG1 isoform expression was induced by mifepristone treatment. Cell growth was assessed using the WST-1 cell proliferation and colony formation assays. RNA interference was used to examine the TIG1 mediating changes in cell growth. Gene expression profiles were determined using microarray and validated using real-time polymerase chain reaction, and Western blot analyses.</p> <p>Results</p> <p>Both TIG1 isoforms were expressed at high levels in normal prostate and colon tissues and were downregulated in colon cancer cell lines. Both TIG1 isoforms significantly inhibited the growth of transiently transfected HCT116 cells and stably expressing TIG1A and TIG1B HCT116 and SW620 cells. Expression of 129 and 55 genes was altered upon induction of TIG1A and TIG1B expression, respectively, in stably expressing HCT116 cells. Of the genes analysed, 23 and 6 genes were upregulated and downregulated, respectively, in both TIG1A and TIG1B expressing cells. Upregulation of the G-protein-coupled receptor kinase 5 (GRK5) was confirmed using real-time polymerase chain reaction and Western blot analyses in both TIG1 stable cell lines. Silencing of TIG1A or GRK5 expression significantly decreased TIG1A-mediated cell growth suppression.</p> <p>Conclusions</p> <p>Expression of both TIG1 isoforms was observed in normal prostate and colon tissues and was downregulated in colon cancer cell lines. Both TIG1 isoforms suppressed cell growth and stimulated GRK5 expression in HCT116 and SW620 cells. Knockdown of GRK5 expression alleviated TIG1A-induced growth suppression of HCT116 cells, suggesting that GRK5 mediates cell growth suppression by TIG1A. Thus, TIG1 may participate in the downregulation of G-protein coupled signaling by upregulating GRK5 expression.</p

Low-energy electronic states of carbon nanocones in an electric field

«Non v’è salvezza al di fuori del mostruoso»; «la diserzione, intrinseca alla letteratura, diventa nel fantastico sfida blasfema, obiezione, tradimento»: in questi passi, lo scrittore italiano Giorgio Manganelli (1922-1990) riafferma la portata trasgressiva della sua opera, indicando nel superamento dei limiti razionali, del verosimile, dell’accettabile o, in altre parole, del narrabile la via per sottrarre la letteratura ad una funzione strumentale. Così, nel privilegiarla come atto di linguaggio e nel disimpegnarla da mansioni mimetico-realistiche, Manganelli la popola di esseri informi e metamorfici. Ad esempio, in opere quali Hilarotragoedia (1964) e Dall’inferno (1985) il mostruoso non si presenta come qualcosa di aberrante, ma piuttosto come il risultato di una sorta di teologia paradossale, in grado di sovvertire o burlare le grandi convenzioni umane. Partendo da tali questioni, l’articolo affronterà il tema del mostro quale infrazione e sovversione essenziali allo scardinamento di un orizzonte ermeneutico antropocentrico, come voleva, tra gli altri, Foucault. «There is no salvation beyond the monstrous»; «desertion, intrinsic to literature, becomes in the Fantastic a blasphemous challenge, objection and betrayal»: with these words, the Italian writer Giorgio Manganelli (1922-1990) reaffirms the transgression of his work. With the overcoming of rational limits, of the plausible, of the acceptable or, in other words, of the tellable, the writer illustrates the way to prevent the use of literature as an instrumental function. Therefore, by using literature as an act of speech and by disengaging it from its mimetic-realistic responsibilities, Manganelli populates it with shapeless and metamorphic beings. In works such as Hilarotragoedia (1964) and From Hell (1985), for example, the monstrous does not resemble something aberrant, but rather it represents a kind of paradoxical theology, capable of subverting or mocking the great human convictions. Starting from these questions, this paper will approach the subject of the monster as infringement and subversion essential for the disruption of a hermeneutic and anthropocentric horizon, as Foucault, among others, wished