821 research outputs found
From photoelectron detachment spectra of BrHBr−, BrDBr− and IHI−, IDI− to vibrational bonding of BrMuBr and IMuI
Photoelectron detachment XLX−(0000) + hν → XLX(vib) + e − + KER (X = Br or I,
L = H or D) at sufficiently low temperatures photoionizes linear dihalogen
anions XLX− in the vibrational ground state (v 1 v 2 l v 3 = 0000) and
prepares the neutral radicals XLX(vib) in vibrational states (vib). At the
same time, part of the photon energy (hν) is converted into kinetic energy
release (KER) of the electron [R. B. Metz, S. E. Bradforth, and D. M. Neumark,
Adv. Chem. Phys. 81, 1 (1992)]. The process may be described approximately in
terms of a Franck-Condon type transfer of the vibrational wavefunction
representing XLX−(0000) from the domain close to the minimum of its potential
energy surface (PES) to the domain close to the linear transition state of the
PES of the neutral XLX. As a consequence, prominent peaks of the photoelectron
detachment spectra (pds) correlate with the vibrational energies E XLX,vib of
states XLX(vib) which are centered at linear transition state. The
corresponding vibrational quantum numbers may be labeled vib = (v 1 v 2 l v 3)
= (000 v 3). Accordingly, the related most prominent peaks in the pds are
labeled v 3. We construct a model PES which mimics the “true” PES in the
domain of transition state such that it supports vibrational states with
energies E XLX,pds,000v3 close to the peaks of the pds labeled v 3 = 0, 2, and
4. Subsequently, the same model PES is also used to calculate approximate
values of the energies E XMuX,0000 of the isotopomers XMuX(0000). For the
heavy isotopomers XHX and XDX, it turns out that all energies E XLX,000 v 3
are above the threshold for dissociation, which means that all heavy XLX(000 v
3) with wavefunctions centered at the transition state are unstable resonances
with finite lifetimes. Turning the table, bound states of the heavy XLX are
van der Waals (vdW) bonded. In contrast, the energies E XMuX,0000 of the light
isotopomers XMuX(0000) are below the threshold for dissociation, with
wavefunctions centered at the transition state. This means that XMuX(0000) are
vibrationally bonded. This implies a fundamental change of the nature of
chemical bonding, from vdW bonding of the heavy XHX, XDX to vibrational
bonding of XMuX. For BrMuBr, the present results derived from experimental pds
of BrHBr− and BrDBr− confirm the recent discovery of vibrational bonding based
on quantum chemical ab initio calculations [D. G. Fleming, J. Manz, K. Sato,
and T. Takayanagi, Angew. Chem., Int. Ed. 53, 13706 (2014)]. The extension
from BrLBr to ILI means the discovery of a new example of vibrational bonding.
These empirical results for the vibrational bonding of IMuI, derived from the
photoelectron spectra of IHI− and IDI−, are supported by ab initio simulations
of the spectra and of the wavefunction representing vibrational bonding of
IMuI
Establishment of Methylation-Specific PCR for the Mouse p53 Gene
Methylation-specific PCR (MSP) of the mouse p53 gene has not yet been reported. We searched the CpG islands, sequenced the bisulfited DNA, and designed PCR primers for methylation and unmethylation sites. DNA from a young mouse produced a strong PCR product with the unmethylated primer and a weaker band with the methylated primer. DNA from an old mouse produced bands of similar intensities with both primers. In radiation-induced tumors, DNA from an old mouse yielded similar bands with both types of primers. We suggest that MSP is a valuable technique for the epigenetic study of the mouse p53 gene
Promoter structure and transcription initiation sites of the human death receptor 5/TRAIL-R2 gene11The nucleotide sequence of the DR5 gene promoter is in the DDBJ/EMBL/GenBank databases with the following accession number: AB054004.
AbstractThe death receptor 5 (DR5) is a receptor for tumor necrosis factor-related apoptosis-inducing ligand and is able to induce apoptosis in various tumor cells. The expression of DR5 is up-regulated at the transcriptional level by p53, genotoxic stress and so on. To investigate the structure of the DR5 gene promoter, we screened and sequenced a genomic clone containing the 5′-flanking region of the DR5 gene. RNase protection assays showed two major transcription start sites around −122 and −137 upstream of the translation initiation codon ATG. Transient transfections with serial 5′-deletion mutants identified the minimal promoter element spanning −198 to −116. Site-directed mutagenesis demonstrated that the DR5 gene promoter has no typical TATA-box, but has two Sp1 sites responsible for the basal transcription activity of the DR5 gene promoter
Current Status and Future Development of Cell Transplantation Therapy for Periodontal Tissue Regeneration
It has been shown that stem cell transplantation can regenerate periodontal tissue, and several clinical trials involving transplantation of stem cells into human patients have already begun or are in preparation. However, stem cell transplantation therapy is a new technology, and the events following transplantation are poorly understood. Several studies have reported side effects and potential risks associated with stem cell transplantation therapy. To protect patients from such risks, governments have placed regulations on stem cell transplantation therapies. It is important for the clinicians to understand the relevant risks and governmental regulations. This paper describes the ongoing clinical studies, basic research, risks, and governmental controls related to stem cell transplantation therapy. Then, one clinical study is introduced as an example of a government-approved periodontal cell transplantation therapy
Definitive Identification of the Transition between Small- to Large-Scale Clustering for Lyman Break Galaxies
We report angular correlation function (ACF) of Lyman Break Galaxies (LBGs)
with unprecedented statistical quality on the basis of 16,920 LBGs at z=4
detected in the 1 deg^2 sky of the Subaru/XMM-Newton Deep Field. The ACF
significantly departs from a power law, and shows an excess on small scale.
Particularly, the ACF of LBGs with i'<27.5 have a clear break between the small
and large-scale regimes at the angular separation of ~7'' whose projected
length corresponds to the virial radius of dark halos with a mass of 10^11-12
Mo, indicating multiple LBGs residing in a single dark halo. Both on small
(2''<theta<3'') and large (40''<theta<400'') scales, clustering amplitudes
monotonically increase with luminosity for the magnitude range of i'=24.5-27.5,
and the small-scale clustering shows a stronger luminosity dependence than the
large-scale clustering. The small-scale bias reaches b~10-50, and the outskirts
of small-scale excess extend to a larger angular separation for brighter LBGs.
The ACF and number density of LBGs can be explained by the cold dark matter
model.Comment: Accepted for publication in ApJL. 5 pages, 4 figures. The text and
Figures 2-4 have been revised. There is no major change which affects to the
main discussion shown in the original preprint. This paper with high
resolution figures is available at
http://www-int.stsci.edu/~ouchi/work/astroph/sxds_z4LBG/ouchi_highres.pdf
(PDF
Pectoralis Major and Serratus Anterior Muscle Flap for Diaphragmatic Reconstruction
We have reported a new reconstruction method using a pectoralis major and serratus anterior muscle flap for diaphragmatic defects after chondrosarcoma resection. The reconstruction of diaphragmatic defects is challenging. In diaphragmatic reconstruction with chest wall defects, strong chest wall reconstruction and diaphragmatic flexibility are important to avoid interference with respiration. The artificial material Gore-Tex is used as the first choice, but it has infection-, exposure-, and durability-related drawbacks. As an alternative method using artificial material, we have reported our new technique—diaphragmatic reconstruction using a reversed-combined pectoralis major and serratus anterior muscle flap
Treatment with DHA/EPA ameliorates atopic dermatitis-like skin disease by blocking LTB4 production
Atopic dermatitis (AD) is caused by both dysregulated immune responses and an impaired skin barrier. Although leukotriene B4 (LTB4) is involved in tissue inflammation that occurs in several disorders, including AD, therapeutic strategies based on LTB4 inhibition have not been explored. Here we demonstrate that progression of an AD-like skin disease in NC/Nga mice is inhibited when docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) is administered together with FK506. Treatment with DHA/EPA and FK506 decreases the clinical score of dermatitis in NC/Nga mice and lowers local LTB4 concentrations. The treatment also suppressed the infiltration of T cells, B cells, eosinophils and neutrophils, and promoted reduced serum IgE levels. Secretion of IL-13 and IL-17A in CD4+ T cells was lower in DHA/EPA- and FK506-treated mice than in mice treated with FK506 alone. The inhibition of disease progression induced by DHA/EPA was reversed by local injection of LTB4, suggesting that the therapeutic effect of DHA/EPA is LTB4-dependent. Our results demonstrate that treatment of AD with DHA/EPA is effective for allergic skin inflammation and acts by suppressing LTB4 production
- …