185 research outputs found
Klotho mice: a novel wound model of aged skin.
BackgroundAs the elderly population continues to expand, it becomes increasingly important to develop treatments to improve wound healing in the elderly. One problem limiting the research is the lack of appropriate animal models for wound healing in elderly patients. We hypothesized that the Klotho mouse of premature aging is a suitable animal model to shed light on many of the biological processes involved in aging skin.MethodsKlotho mice (kl/kl), Klotho-heterozygous mice (kl/+), and wild-type mice (+/+) were wounded, and the area of the wound was measured every 3 days until the wound was healed. To compare the klotho phenotype with wild-type mice, wounds were also harvested at 4 and 7 days after wounding. For histological examination, paraffin-embedded sections were stained with hematoxylin and eosin and Masson trichrome. Collagen expression in the wound was also studied by analyzing messenger RNA using real-time polymerase chain reaction.ResultsKlotho mice showed a significantly slower rate of wound closure compared with Klotho-heterozygous mice and wild-type mice. Histology showed substantial less healing and collagen deposition in the wounds of the Klotho mice. The expression of collagen messenger RNA in Klotho mice was also less than that in heterozygous and wild-type mice. The Klotho mice exhibited significant phenotypic similarities with aged skin, such as atrophy and delayed wound healing.ConclusionThese preliminary data suggest that the Klotho mouse may be a model to further investigate wound healing in the elderly
QCD Correction to Neutralino Annihilation Process and Dark Matter Density in Supersymmetric Models
We calculate QCD correction to the neutralino annihilation cross section into
quark anti-quark final state and discuss its implications to the calculation of
neutralino relic density. We see that the QCD correction enhances the
pair-annihilation cross section by O(10 %) when final-state quarks are
non-relativistic. Consequently, when the lightest neutralinos dominantly
annihilate into a t\bar{t} pair, the relic density of the lightest neutralino
is significantly affected by the QCD correction, in particular when the
lightest-neutralino mass is close to the top-quark mass.Comment: 19 pages, 5 figure
Big-Bang Nucleosynthesis with Unstable Gravitino and Upper Bound on the Reheating Temperature
We study the effects of the unstable gravitino on the big-bang
nucleosynthesis. If the gravitino mass is smaller than \sim 10 TeV, primordial
gravitinos produced after the inflation are likely to decay after the big-bang
nucleosynthesis starts, and the light element abundances may be significantly
affected by the hadro- and photo-dissociation processes as well as by the p n
conversion process. We calculate the light element abundances and derived upper
bound on the reheating temperature after the inflation. In our analysis, we
calculate the decay parameters of the gravitino (i.e., lifetime and branching
ratios) in detail. In addition, we performed a systematic study of the hadron
spectrum produced by the gravitino decay, taking account of all the hadrons
produced by the decay products of the gravitino (including the daughter
superparticles). We discuss the model-dependence of the upper bound on the
reheating temperature.Comment: 32 pages, 11 figure
Crucial Dependence of ``Precarious'' and ``Autonomous'' phi^4s Upon the Normal-ordering Mass
Using the Gaussian wave-functional approach with the normal-ordering
renormalization prescription, we show that for the (3+1)-dimensional massive
lambda phi^4 theory, ``precarious'' and ``autonomous'' phi^4s can exist if and
only if the normal-ordering mass is equal to the classical masses at the
symmetrc and asymmetric vacua, respectively.Comment: 6 pages, no figures, Revtex file, accepted for publication in Mod.
Phys. Lett.
Big-Bang Nucleosynthesis and Gravitino
We derive big-bang nucleosynthesis (BBN) constraints on both unstable and
stable gravitino taking account of recent progresses in theoretical study of
the BBN processes as well as observations of primordial light-element
abundances. In the case of unstable gravitino, we set the upper limit on the
reheating temperature assuming that the primordial gravitinos are mainly
produced by the scattering processes of thermal particles. For stable
gravitino, we consider Bino, stau and sneutrino as the next-to-the-lightest
supersymmetric particle and obtain constraints on their properties. Compared
with the previous works, we improved the following points: (i) we use the most
recent observational data, (ii) for gravitino production, we include
contribution of the longitudinal component, and (iii) for the case with
unstable long-lived stau, we estimate the bound-state effect of stau accurately
by solving the Boltzmann equation.Comment: 27 pages, 16 figure
Measurement of hepatitis B virus core-related antigen is valuable for identifying patients who are at low risk of lamivudine resistance
ArticleLIVER INTERNATIONAL. 26(1): 90-96 (2006)journal articl
Immunological and molecular epidemiological characteristics of acute and fulminant viral hepatitis A
<p>Abstract</p> <p>Background</p> <p>Hepatitis A virus is an infection of liver; it is hyperendemic in vast areas of the world including India. In most cases it causes an acute self limited illness but rarely fulminant. There is growing concern about change in pattern from asymptomatic childhood infection to an increased incidence of symptomatic disease in the adult population.</p> <p>Objective</p> <p>In-depth analysis of immunological, viral quantification and genotype of acute and fulminant hepatitis A virus.</p> <p>Methods</p> <p>Serum samples obtained from 1009 cases of suspected acute viral hepatitis was employed for different biochemical and serological examination. RNA was extracted from blood serum, reverse transcribed into cDNA and amplified using nested PCR for viral quantification, sequencing and genotyping. Immunological cell count from freshly collected whole blood was carried out by fluorescence activated cell sorter.</p> <p>Results</p> <p>Fulminant hepatitis A was mostly detected with other hepatic viruses. CD8<sup>+ </sup>T cells count increases in fulminant hepatitis to a significantly high level (P = 0.005) compared to normal healthy control. The immunological helper/suppressor (CD4<sup>+</sup>/CD8<sup>+</sup>) ratio of fulminant hepatitis was significantly lower compared to acute cases. The serologically positive patients were confirmed by RT-PCR and total of 72 (69.2%) were quantified and sequenced. The average quantitative viral load of fulminant cases was significantly higher (<it>P </it>< 0.05). There was similar genotypic distribution in both acute and fulminant category, with predominance of genotype IIIA (70%) compared to IA (30%).</p> <p>Conclusions</p> <p>Immunological factors in combination with viral load defines the severity of the fulminant hepatitis A. Phylogenetic analysis of acute and fulminant hepatitis A confirmed genotypes IIIA as predominant against IA with no preference of disease severity.</p
Defending the genome from the enemy within:mechanisms of retrotransposon suppression in the mouse germline
The viability of any species requires that the genome is kept stable as it is transmitted from generation to generation by the germ cells. One of the challenges to transgenerational genome stability is the potential mutagenic activity of transposable genetic elements, particularly retrotransposons. There are many different types of retrotransposon in mammalian genomes, and these target different points in germline development to amplify and integrate into new genomic locations. Germ cells, and their pluripotent developmental precursors, have evolved a variety of genome defence mechanisms that suppress retrotransposon activity and maintain genome stability across the generations. Here, we review recent advances in understanding how retrotransposon activity is suppressed in the mammalian germline, how genes involved in germline genome defence mechanisms are regulated, and the consequences of mutating these genome defence genes for the developing germline
Mass spectrum of primordial black holes from inflationary perturbation in the Randall-Sundrum braneworld: a limit on blue spectra
The mass spectrum of the primordial black holes formed by density
perturbation in the radiation-dominated era of the Randall-Sundrum type-2
cosmology is given. The spectrum coincides with standard four-dimensional one
on large scales but the deviation is apparent on smaller scales. The mass
spectrum is initially softer than standard four-dimensional one, while after
accretion during the earliest era it becomes harder than that. We also show
expected extragalactic diffuse photon background spectra varying the initial
perturbation power-law power spectrum and give constraints on the blue spectra
and/or the reheating temperature. The most recent observations on the small
scale density perturbation from WMAP, SDSS and Lyman-\alpha Forest are used.
What we get are interpreted as constraints on the smaller scale inflation on
the brane connected to the larger one at the scale of Lyman-\alpha Forest. If
we set the bulk curvature radius to be 0.1 mm and assume the reheating
temperature is higher than 10^6 GeV, the scalar spectral index from the smaller
scale inflation is constrained to be n \lesssim 1.3. Typically, the constraints
are tighter than standard four-dimensional one, which is also revised by us
using the most recent observations.Comment: 19 pages, 6 figures; typos corrected, references added, published in
JCA
Chitosan-modified cotton thread for the preconcentration and colorimetric trace determination of Co(II)
In this work we propose a thread-based microfluidic device (μTAD) for the preconcentration and colorimetric determination of Co(II) in water using a digital image. The reaction is based on complexation of Co(II) by 4-(2- pyridylazo) resorcinol (PAR), which changes the detection zone from yellow to red. PAR is immobilized in a chitosan membrane to retain the complex in the detection zone. The designed μTAD makes it possible to pre- concentrate and determine cobalt between 25 and 600 µg·L−1 with a relative standard deviation of 4% (n = 5), and a detection limit of 6.5 µg·L−1. The device permits an enhancement factor of 11 by combining the use of a chitosan retention membrane and a sample volume of 50 µL. Recovery experiments were performed in tap water to evaluate the accuracy of the method, and the results obtained compared to a reference method presents an error no higher than 5.7%This work was founded by Spanish “Ministerio de Economía y Competitividad” under Project CTQ2016-78754-C2-1-R and Junta de Andalucía under Projects B-FQM-243-UGR18 and P18-RT-2961. The project was partially supported by European Regional Development Funds (ERDF). Supporting Research in the State of Minas Gerais (Fapemig) (CEX-APQ-02436-15)
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