303 research outputs found
Complete mitochondrial genomes and nuclear ribosomal RNA operons of two species of Diplostomum (Platyhelminthes: Trematoda): a molecular resource for taxonomy and molecular epidemiology of important fish pathogens
© 2015 Brabec et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License
(http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium,
provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://
creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The attached file is the published version of the article
Impurities in Heisenberg Antiferromagnets
The Heisenberg Antiferromagnet is studied in the presence of two kinds
of local impurities. First, a perturbed antiferromagnetic bond with
at the center of an even-length open chain is considered. Using the density
matrix renormalization group method we find that, for sufficiently strong or
weak , a bound state is localized at the impurity site, giving rise to an
energy level in the Haldane gap. The energy of the bound state is in agreement
with perturbative results, based on chain-end excitations, both in the
weak and strong coupling limit. In a region around the uniform limit, ,
no states are found with energy below the Haldane gap. Secondly, a
impurity at the center of an otherwise even-length open chain is considered.
The coupling to the impurity is varied. Bound states in the Haldane gap
are found {\it only} for sufficiently weak (antiferromagnetic) coupling. For a
impurity coupled with a strong (antiferromagnetic) bond, {\it no}
states are found in the Haldane. Our results are in good qualitative agreement
with recent experiments on doped NENP and YBaNiO.Comment: 29 pages, RevTeX 3.0, 12 uuencoded postscript figures include
Magnetization profiles and NMR spectra of doped Haldane chains at finite temperatures
Open segments of S=1 antiferromagnetic spin chains are studied at finite
temperatures and fields using continuous time Quantum Monte Carlo techniques.
By calculating the resulting magnetization profiles for a large range of chain
lengths with fixed field and temperature we reconstruct the experimentally
measured NMR spectrum of impurity doped YBaNiMgO. For
temperatures above the gap the calculated NMR spectra are in excellent
agreement with the experimental results, confirming the existence of
excitations at the end of open S=1 chain segments. At temperatures below the
gap, neglecting inter chain couplings, we still find well defined peaks in the
calculated NMR spectra corresponding to the chain end excitations. At
low temperatures, inter chain couplings could be important, resulting in a more
complicated phase.Comment: 7 pages, 5 figures, minor correction
Vanadium
International audienceVanadium (chemical symbol, V) is a d-block transition metal,silver in color, appearing in the first long period of the peri-odic table between titanium and chromium. Vanadium hastwo stable isotopes: 50V and 51V, with atomic abundance of0.25 % and 99.75 %, respectively. Vanadium has several oxidation forms (between 2+ and 5+). In the lithosphere, Voccurs as reducing V(III) form, whereas in oxidizing con- ditions V prevails under V(IV) form. Vanadium(II) is partic- ularly unstable in the environment. Vanadium(III) is more stable than V(II), but it is also gradually oxidized by the air or dissolved oxygen. Vanadium(V) is expected to be the prevailing form in waters exposed to atmospheric oxygen, whereas V(IV) may be present in reducing environments. Depending upon geometry and environment, V ionic radii vary between 36 pm and 79 pm. Vanadium has a high melting point of 1910 42 C and is a mildly incompatible, refractory,lithophile (siderophile in the iron core and chondrites) ele- ment. Vanadium has an electronegativity of 1.63 on the Pau- ling scale and displays a first ionization potential of 6.74 eV. More details can be found in Richards (2006) and Haynes (2015)
Analysis of clinically relevant somatic mutations in high-risk head and neck cutaneous squamous cell carcinoma
Cutaneous squamous cell carcinoma is the second most prevalent malignancy, most frequently occurring in the head and neck (head and neck cutaneous squamous cell carcinoma). Treatment of locally advanced or metastatic disease is associated with functional morbidity and disfigurement. Underlying genetic mechanisms are poorly understood. Targeted sequencing of 48 clinically relevant genes was performed on DNA extracted from formalinfixed and paraffin-embedded high-risk primary head and neck cutaneous squamous cell carcinomas that remained non-metastatic at minimum follow-up of 24 months. Associations of somatic mutations with clinicopathologic characteristics were evaluated and compared with those described in the literature for metastatic disease. Alterations in 44 cancer-associated genes were identified. TP53 was mutated in 100% of cases; APC, ATM, ERBB4, GNAQ, KIT, RB1 and ABL1 were altered in 60% of cases. FGFR2 mutations (40%) were exclusively seen in patients with perineural invasion. MLH1 mutations were exclusively seen in the two younger patients (\u3c45 \u3eyears). Lower incidences of NOTCH1 mutations were observed compared with that described in metastatic head and neck cutaneous squamous cell carcinoma in the literature. Somatic mutations susceptible to EGFR inhibitors, and other small molecular targeted therapeutics were seen in 60% of cases. This study provides insights into somatic mutations in non-metastatic, high-risk head and neck cutaneous squamous cell carcinoma and identifies potential therapeutic targets. Alterations in FGFR2 and NOTCH1 may have roles in local and distant disease progression
Involvement in Crime, Individual Resources and Structural Constraints: Processes of Cumulative (Dis)Advantage in a Stockholm Birth Cohort
Equal Time Correlations in Haldane Gap Antiferromagnets
The antiferromagnetic Heisenberg chain both with and without single ion
anisotropy is studied. Using the recently proposed density matrix
renormalization group technique we calculate the energy gaps as well as several
different correlation functions. The two gaps, ,
along with associated correlation lengths and velocities are determined. The
numerical results are shown to be in good agreement with theoretical
predictions derived from the nonlinear sigma model and a free boson model. We
also study the excitations that occur at the ends of open chains; in
particular we study the behavior associated with open boundary conditions,
using a model of spins coupled to the free bosons.Comment: 32 pages, uufiles encoded REVTEX 3.0, 19 postscript figures included,
UBCTP-93-02
Intra-arterial chemoradiation for T3-4 oral cavity cancer: Treatment outcomes in comparison to oropharyngeal and hypopharyngeal carcinoma
<p>Abstract</p> <p>Background</p> <p>Surgery followed by radiotherapy is the standard of care for resectable locally advanced oral cavity squamous cell carcinoma (SCC). We report the treatment outcomes of patients with T3-T4 SCC of the oral cavity treated with chemoradiation, an alternative approach.</p> <p>Patients and methods</p> <p>From a series of 240 patients with stage III-IV carcinoma of the upper aerodigestive tract who were treated consecutively according to the RADPLAT protocol, a subset analysis of 155 patients with T3-T4 SCC (Oral cavity SCC N = 22, oropharynx SCC N = 94 and hypopharynx SCC N = 39), was performed. The goal was to test the hypothesis that oral cavity SCC treated with chemoradiation has similar outcomes to the two comparison sites.</p> <p>Results</p> <p>With a median follow-up of 58 months, local disease control was 69% and the overall survival was 37%. In comparison, local disease control for the oropharynx and hypopharynx groups was 86% and 79% respectively. The overall survival rate for the oropharyngeal and hypopharyngeal groups were 41% and 6% respectively</p> <p>Conclusion</p> <p>Patients with locally advanced oral cavity cancer treated with the chemoradiation protocol RADPLAT have outcomes that are equal or better compared to patients with similar disease involving the oropharynx and hypopharynx</p
Long-term consequences of being not in employment, education or training as a young adult. Stability and change in three Swedish birth cohorts
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