1,881 research outputs found
Integrable Open Spin Chains from Flavored ABJM Theory
We compute the two-loop anomalous dimension matrix in the scalar sector of
planar flavored ABJM theory. Using coordinate Bethe ansatz, we
obtain the reflection matrix and confirm that the boundary Yang-Baxter
equations are satisfied. This establishes the integrability of this theory in
the scalar sector at the two-loop order.Comment: v2, 25 pages, 2 figures, minor corrections, references adde
Geometric bionics: Lotus effect helps polystyrene nanotube films get good blood compatibility
Various biomaterials have been widely used for manufacturing biomedical applications including artificial organs, medical devices and disposable clinical apparatus, such as vascular prostheses, blood pumps, artificial kidney, artificial hearts, dialyzers and plasma separators, which could be used in contact with blood^1^. However, the research tasks of improving hemocompatibility of biomaterials have been carrying out with the development of biomedical requirements^2^. Since the interactions that lead to surface-induced thrombosis occurring at the blood-biomaterial interface become a reason of familiar current complications with grafts therapy, improvement of the blood compatibility of artificial polymer surfaces is, therefore a major issue in biomaterials science^3^. After decades of focused research, various approaches of modifying biomaterial surfaces through chemical or biochemical methods to improve their hemocompatibility were obtained^1^. In this article, we report that polystyrene nanotube films with morphology similar to the papilla on lotus leaf can be used as blood-contacted biomaterials by virtue of Lotus effect^4^. Clearly, this idea, resulting from geometric bionics that mimicking the structure design of lotus leaf, is very novel technique for preparation of hemocompatible biomaterials
Experimental Upconversion of Images
We experimentally demonstrate the up-conversion of light carrying an image
from the infrared spectrum to the visible spectrum using four-wave mixing via a
ladder-type configuration in an atomic vapor. The results we obtained show the
high correlation between the input image and the up-converted image. We also
discuss the possible influences of experimental parameters on the resolution.
Our work might be useful for research in astrophysics, night-vision technology,
and chemical sensing.Comment: Accepted by PR
New advances of DNA methylation in liver fibrosis, with special emphasis on the crosstalk between microRNAs and DNA methylation machinery
AbstractEpigenetics refers to the study of heritable changes in the pattern of gene expression that is controlled by a mechanism specifically not due to changes the primary DNA sequence. Well-known epigenetic mechanisms include DNA methylation, post-translational histone modifications and RNA-based mechanisms including those controlled by small non-coding RNAs (miRNAs). Recent studies have shown that epigenetic modifications orchestrate the hepatic stellate cell (HSC) activation and liver fibrosis. In this review we focus on the aberrant methylation of CpG island promoters of select genes is the prominent epigenetic mechanism to effectively silence gene transcription facilitating HSC activation and liver fibrosis. Furthermore, we also discuss epigenetic dysregulation of tumor-suppressor miRNA genes by promoter DNA methylation and the interaction of DNA methylation with miRNAs involved in the regulation of HSC activation and liver fibrosis. Recent advances in epigenetics alterations in the pathogenesis of liver fibrosis and their possible use as new therapeutic targets and biomarkers
Comparative Cytogenetics Analysis of Chlamys farreri, Patinopecten yessoensis, and Argopecten irradians with C0t-1 DNA by Fluorescence In Situ Hybridization
The chromosomes of
Chlamys farreri,
Patinopecten yessoensis, and
Argopecten irradians were
studied by FISH using C. farreri C0t-1 DNA probes. The results showed that C0t-1 DNA signals spread on all chromosomes in the three scallops, whereas signal density and intensity were different strikingly. Clustering brighter signals presented in the centromeric and telomeric regions of most C. farreri chromosomes, and in the centromeric or pericentromeric regions of several P. yessoensis chromosomes. Comparative analysis of the mapping indicated a relatively higher homology in the repetitive DNA sequences of the genome between C. farreri and P. yessoensis than that between C. farreri and A. irradians. In addition, FISH showed that the distribution of C0t-1 DNA clustering signals in C. farreri displayed completely similar signal bands between homologous chromosomes. Based on the C0t-1 DNA fluorescent bands, a more exact karyotype of C. farreri has been obtained. In this study, the comparative analysis based on C0t-1 DNA provides a new insight into
the chromosomal reconstructions during the evolution process, and
it is helpful for understanding an important source of genomic
diversity, species relationships, and genome
evolution
Molecular cloning of dihydroflavonol 4-reductase gene from grape berry and preparation of an anti-DFR polyclonal antibody
Dihydroflavonol 4-reductase (DFR, EC 1.1.1.219) is a key enzyme of the flavonoid pathway, which synthesizes numerous secondary metabolites to determine the quality of grape berry and wine. The full-length dfr cDNA with 1014 bp was cloned from grape berry, and then introduced into an expressed plasmid pET-30a (+) vector at the EcoR I and Xho I restriction sites. With induction of the isopropyl-β-D-thiogalactoside (IPTG), the pET-dfr was highly expressed in Escherichia coli BL21 (DE3) pLysS cells. A fusion protein with the His-Tag was purified through Ni-NTA His Bind Resin and then used as the antigen to immunize a New Zealand rabbit. The resulting antiserum was further purified precipitated by 50 % saturated ammonium sulfate and DEAE-Sepharose FF chromatography to obtain the immunoglobulin G (IgG) fraction. The resulting polyclonal antibody was found capable of immuno-recognizing the DFR of the crude protein extracts from grape berry. This work undoubtedly provides the possibility for further studies on biological regulation of DFR activity in grape berry.
Isospin Effect on the Process of Multifragmentation and Dissipation at Intermediate Energy Heavy Ion Collisions
In the simulation of intermediate energy heavy ion collisions by using the
isospin dependent quantum molecular dynamics, the isospin effect on the process
of multifragmentation and dissipation has been studied. It is found that the
multiplicity of intermediate mass fragments for the neutron-poor
colliding system is always larger than that for the neutron-rich system, while
the quadrupole of single particle momentum distribution for the
neutron-poor colliding system is smaller than that of the neutron-rich system
for all projectile-target combinations studied at the beam energies from about
50MeV/nucleon to 150MeV/nucleon. Since depends strongly on isospin
dependence of in-medium nucleon-nucleon cross section and weakly on symmetry
potential at the above beam energies, it may serve as a good probe to extract
the information on the in-medium nucleon-nucleon cross section. The correlation
between the multiplicity of intermediate mass fragments and the total
numer of charged particles has the behavior similar to , which
can be used as a complementary probe to the in-medium nucleon-nucleon cross
section.Comment: 18 pages, 9 figure
Robust and clean Majorana zero mode in the vortex core of high-temperature superconductor (Li0.84Fe0.16)OHFeSe
The Majorana fermion, which is its own anti-particle and obeys non-abelian
statistics, plays a critical role in topological quantum computing. It can be
realized as a bound state at zero energy, called a Majorana zero mode (MZM), in
the vortex core of a topological superconductor, or at the ends of a nanowire
when both superconductivity and strong spin orbital coupling are present. A MZM
can be detected as a zero-bias conductance peak (ZBCP) in tunneling
spectroscopy. However, in practice, clean and robust MZMs have not been
realized in the vortices of a superconductor, due to contamination from
impurity states or other closely-packed Caroli-de Gennes-Matricon (CdGM)
states, which hampers further manipulations of Majorana fermions. Here using
scanning tunneling spectroscopy, we show that a ZBCP well separated from the
other discrete CdGM states exists ubiquitously in the cores of free vortices in
the defect free regions of (Li0.84Fe0.16)OHFeSe, which has a superconducting
transition temperature of 42 K. Moreover, a Dirac-cone-type surface state is
observed by angle-resolved photoemission spectroscopy, and its topological
nature is confirmed by band calculations. The observed ZBCP can be naturally
attributed to a MZM arising from this chiral topological surface states of a
bulk superconductor. (Li0.84Fe0.16)OHFeSe thus provides an ideal platform for
studying MZMs and topological quantum computing.Comment: 32 pages, 15 figures (supplementary materials included), accepted by
PR
Vacuum Energy Density and Cosmological Constant in dS Brane World
We discuss the vacuum energy density and the cosmological constant of dS
brane world with a dilaton field. It is shown that a stable AdS brane can
be constructed and gravity localization can be realized. An explicit relation
between the dS bulk cosmological constant and the brane cosmological constant
is obtained. The discrete mass spectrum of the massive scalar field in the
AdS brane is used to acquire the relationship between the brane
cosmological constant and the vacuum energy density. The vacuum energy density
in the brane gotten by this method is in agreement with astronomical
observations.Comment: 16 pages,4 figure
- …