1,519 research outputs found
Neurodevelopment and Endocrine Disruption
In this article I explore the possibility that contaminants contribute to the increasing prevalence of attention deficit hyperactivity disorder, autism, and associated neurodevelopmental and behavioral problems in developed countries. I discuss the exquisite sensitivity of the embryo and fetus to thyroid disturbance and provide evidence of human in utero exposure to contaminants that can interfere with the thyroid. Because it may never be possible to link prenatal exposure to a specific chemical with neurodevelopmental damage in humans, I also present alternate models where associations have been made between exposure to specific chemicals or chemical classes and developmental difficulties in laboratory animals, wildlife, and humans
Identifying the favored mutation in a positive selective sweep.
Most approaches that capture signatures of selective sweeps in population genomics data do not identify the specific mutation favored by selection. We present iSAFE (for "integrated selection of allele favored by evolution"), a method that enables researchers to accurately pinpoint the favored mutation in a large region (∼5 Mbp) by using a statistic derived solely from population genetics signals. iSAFE does not require knowledge of demography, the phenotype under selection, or functional annotations of mutations
Brief Report: AIP Mutation in Pituitary Adenomas in the 18th Century and Today
From New England Journal of Medicine, Volume 364, issue 1, p.43-50. Copyright © (2011) Massachusetts Medical Society. Reprinted with permission.Gigantism results when a growth hormone–secreting pituitary adenoma is present
before epiphyseal fusion. In 1909, when Harvey Cushing examined the skeleton of
an Irish patient who lived from 1761 to 1783,1-3 he noted an enlarged pituitary
fossa. We extracted DNA from the patient’s teeth and identified a germline mutation
in the aryl hydrocarbon–interacting protein gene (AIP). Four contemporary
Northern Irish families who presented with gigantism, acromegaly, or prolactinoma
have the same mutation and haplotype associated with the mutated gene. Using
coalescent theory, we infer that these persons share a common ancestor who lived
about 57 to 66 generations earlier
A natural little hierarchy for RS from accidental SUSY
We use supersymmetry to address the little hierarchy problem in
Randall-Sundrum models by naturally generating a hierarchy between the IR scale
and the electroweak scale. Supersymmetry is broken on the UV brane which
triggers the stabilization of the warped extra dimension at an IR scale of
order 10 TeV. The Higgs and top quark live near the IR brane whereas light
fermion generations are localized towards the UV brane. Supersymmetry breaking
causes the first two sparticle generations to decouple, thereby avoiding the
supersymmetric flavour and CP problems, while an accidental R-symmetry protects
the gaugino mass. The resulting low-energy sparticle spectrum consists of
stops, gauginos and Higgsinos which are sufficient to stabilize the little
hierarchy between the IR scale and the electroweak scale. Finally, the
supersymmetric little hierarchy problem is ameliorated by introducing a singlet
Higgs field on the IR brane.Comment: 37 pages, 3 figures; v2: minor corrections, version published in JHE
Mindfulness based interventions in multiple sclerosis: a systematic review
<b>Background</b> Multiple sclerosis (MS) is a stressful condition; depression, anxiety, pain and fatigue are all common problems. Mindfulness based interventions (MBIs) mitigate stress and prevent relapse in depression and are increasingly being used in healthcare. However, there are currently no systematic reviews of MBIs in people with MS. This review aims to evaluate the effectiveness of MBIs in people with MS.<p></p>
<b>Methods</b> Systematic searches were carried out in seven major databases, using both subject headings and key words. Papers were screened, data extracted, quality appraised, and analysed by two reviewers independently, using predefined criteria. Study quality was assessed using the Cochrane Collaboration risk of bias tool. Perceived stress was the primary outcome. Secondary outcomes include mental health, physical health, quality of life, and health service utilisation. Statistical meta-analysis was not possible. Disagreements were adjudicated by a third party reviewer.<p></p>
<b>Results</b> Three studies (n = 183 participants) were included in the final analysis. The studies were undertaken in Wales (n = 16, randomised controlled trial - (RCT)), Switzerland (n = 150, RCT), and the United States (n = 17, controlled trial). 146 (80%) participants were female; mean age (SD) was 48.6 (9.4) years. Relapsing remitting MS was the main diagnostic category (n = 123, 67%); 43 (26%) had secondary progressive disease; and the remainder were unspecified. MBIs lasted 6–8 weeks; attrition rates were variable (5-43%); all employed pre- post- measures; two had longer follow up; one at 3, and one at 6 months. Socio-economic status of participants was not made explicit; health service utilisation and costs were not reported. No study reported on perceived stress. All studies reported quality of life (QOL), mental health (anxiety and depression), physical (fatigue, standing balance, pain), and psychosocial measures. Statistically significant beneficial effects relating to QOL, mental health, and selected physical health measures were sustained at 3- and 6- month follow up.<p></p>
<b>Conclusion</b> From the limited data available, MBIs may benefit some MS patients in terms of QOL, mental health, and some physical health measures. Further studies are needed to clarify how MBIs might best serve the MS population.<p></p>
Nanostructured Pt(NH3)4Cl2/SiO2 for nanomedicine: catalytic degradation of DNA in cancer cells
In vivo suppression of glioblastoma multiforme (GBM) in Wistar rats using silica-shelled biocatalytic Pt(NH3)4Cl2 nanoparticles is reported. These nanoparticles were synthesized by a sol-gel technique and characterized by SEM and HRTEM imaging. We confirmed morphological uniformity (30 nm) and surface acidity of the nanoparticles, respectively, by TEM imaging and FTIR spectral analysis. Interestingly, treatment of Wistar rats intraperitoneally inoculated with C6 cells using the biocatalysts resulted in considerable tumor shrinkage. Efficiency of the biocatalyst to shrink a tumor is superior to that by the commercial cytotoxic agent cisplatin. The tumor suppression property of Pt(NH3)4Cl2 nanoparticles is attributed to catalytic damage of DNA in C6 cells
Radiative contribution to neutrino masses and mixing in SSM
In an extension of the minimal supersymmetric standard model (popularly known
as the SSM), three right handed neutrino superfields are introduced to
solve the -problem and to accommodate the non-vanishing neutrino masses
and mixing. Neutrino masses at the tree level are generated through parity
violation and seesaw mechanism. We have analyzed the full effect of one-loop
contributions to the neutrino mass matrix. We show that the current three
flavour global neutrino data can be accommodated in the SSM, for both
the tree level and one-loop corrected analyses. We find that it is relatively
easier to accommodate the normal hierarchical mass pattern compared to the
inverted hierarchical or quasi-degenerate case, when one-loop corrections are
included.Comment: 51 pages, 14 figures (58 .eps files), expanded introduction, other
minor changes, references adde
It is a Graviton! or maybe not
The discovery of Kaluza-Klein (KK) gravitons is a smoking gun of extra
dimensions. Other scenarios, however, could give rise to spin-two resonances of
a new strongly-coupled sector and act as impostors. In this paper we prove that
a spin-two resonance does not couple to the Standard Model through
dimension-four operators. We then show that the massive graviton and its
impostor both couple to the Standard Model through the same dimension-five
operators. Therefore the spin determination is identical. Nevertheless, we also
show that one can use the ratio of branching ratios to photons and to jets for
distinguishing between KK gravitons and their impostors. The capacity to
distinguish between KK gravitons and impostors is a manifestation of the
breakdown of the duality between AdS and strongly-coupled theories.Comment: 14 pages, 3 figures, 1 table. References added, typos correcte
Mass-Matching in Higgsless
Modern extra-dimensional Higgsless scenarios rely on a mass-matching between
fermionic and bosonic KK resonances to evade constraints from precision
electroweak measurements. After analyzing all of the Tevatron and LEP bounds on
these so-called Cured Higgsless scenarios, we study their LHC signatures and
explore how to identify the mass-matching mechanism, the key to their
viability. We find singly and pair produced fermionic resonances show up as
clean signals with 2 or 4 leptons and 2 hard jets, while neutral and charged
bosonic resonances are visible in the dilepton and leptonic WZ channels,
respectively. A measurement of the resonance masses from these channels shows
the matching necessary to achieve . Moreover, a large single
production of KK-fermion resonances is a clear indication of compositeness of
SM quarks. Discovery reach is below 10 fb of luminosity for resonances
in the 700 GeV range.Comment: 28 pages, 18 figure
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