861 research outputs found
Controlled depolymerisation, as assessed by analytical ultracentrifugation, of low molecular weight chitosan for potential use in archaeological conservation
The heterogeneity and molecular weight of a chitosan of low molecular weight (molar mass) and low degree of acetylation (0.1), for potential use as a consolidant for decayed archaeological wood, has been examined by sedimentation velocity and sedimentation equilibriumin the analytical ultracentrifuge before and after depolymerisation. Sedimentation velocity before polymerisation revealed a uniform distribution of sedimentation coefficient with little concentration dependence. SEDFIT-MSTAR analysis revealed a weight average molecular weight Mw of (14.2 + 1.2) kDa, and polydispersity index of ~ 1.2. Further analysis using MULTISIG revealed a distribution of material between 2-20 kDa and consistent with the weight average Mw. Controlled depolymerisation using hydrogen peroxide and UV in an acetic acid medium reduced this to (4.9 + 0.7) kDa, with a similar polydispersity. The depolymerised material appears to be within the range that has been predicted to fully penetrate into archaeological wood. The consequences for this and the use of the analytical ultracentrifuge in wood conservation strategies is considered
How many sentinel nodes should be harvested in oral squamous cell carcinoma?
The number of harvested lymph nodes when performing sentinel lymph node (SLN) biopsy remains controversial. The aim of this study was to examine the maximum number of nodes to be harvested for histopathological analysis. We also wanted to determine if the level of radioactivity within a SLN or its size were indicators for the likelihood of nodal metastases. The SLNs from 34 neck dissection specimens from patients with T1/T2 N0 oral and oropharyngeal carcinomas were included. Altogether 76 SLNs were measured for radioactivity and lymph node dimensions and volume. Tumour was identified in 16 of 76 nodes (positive nodes), and the remaining 60 nodes were free from tumour (negative nodes). In 9 of 16 cases, metastases were in the hottest node. Two patients had more than one positive SLN: the first and fourth hottest in one and the second and fourth hottest nodes in another contained tumour. However, all patients would have been staged accurately if only the hottest three sentinel nodes had been retrieved. Lymph nodes that contained tumour had a greater maximum diameter than non-metastatic SLNs. To stage the neck accurately, only the three hottest lymph nodes required sampling
The problem of obesity among adolescents in Hong Kong: a comparison using various diagnostic criteria
<p>Abstract</p> <p>Background</p> <p>Obesity is now a global epidemic. In this study, we aimed to assess the rates of obesity using several major diagnostic criteria in Chinese school adolescents in Hong Kong.</p> <p>Methods</p> <p>This is a cross-sectional study. Using a computer-generated coding system, we randomly selected schools from different geographical regions in Hong Kong to obtain a representative sample. Subjects aged 11–18 years of age were randomly selected from different class of the schools. Their rates of obesity according to four different international and local criteria were compared [International Obesity Task Force (IOTF) 2000 criterion; the Group of China Obesity Task Force (COTF) 2004 criterion; Centers for Disease Control and Prevention (CDC) 2000 Growth Charts and the Hong Kong Growth Survey (HKGS) charts in 1993].</p> <p>Results</p> <p>Of the 2098 adolescents [982 (46.8%) boys and 1116 (53.2%) girls], the mean age (± SD) was 15.1 ± 1.8 years (range: 11–18 years; median: 15.0 years). The crude rates of obesity were similar based on IOTF, COTF or CDC criteria (boys: 3.9–6.0%, girls: 1.8–3.7%), however, the rate increased to 11–27% if the HKGS charts were used. Obesity rate varied markedly according to age. It decreased from 8–10% among those aged 12–13 years to 2–4% among those aged 17–18 years.</p> <p>Conclusion</p> <p>The prevalence of obesity in Hong Kong adolescents using various diagnostic criteria were similar except for the 1993 HKGS criteria, which gave an exceeding high figure. Using the IOTF, COTF or CDC criteria, the adolescent obesity in Hong Kong varied from 1.8% to 6.0%.</p
Hypnosis for hot flashes among postmenopausal women study: A study protocol of an ongoing randomized clinical trial
<p>Abstract</p> <p>Background</p> <p>Hot flashes are a highly prevalent problem associated with menopause and breast cancer treatments. The recent findings from the Women's Health Initiative have important implications for the significance of a non-hormonal, mind-body intervention for hot flashes in breast cancer survivors. Women who take hormone therapy long-term may have a 1.2 to 2.0 fold increased risk of developing breast cancer. In addition, it is now known that hormone therapy with estrogen and progestin is associated with increased risk of cardiovascular disease and stroke. Currently there are limited options to hormone replacement therapy as non-hormonal pharmacological agents are associated with only modest activity and many adverse side effects. Because of this there is a need for more alternative, non-hormonal therapies. Hypnosis is a mind-body intervention that has been shown to reduce self-reported hot flashes by up to 68% among breast cancer survivors, however, the use of hypnosis for hot flashes among post-menopausal women has not been adequately explored and the efficacy of hypnosis in reducing physiologically measured hot flashes has not yet been determined.</p> <p>Methods/design</p> <p>A sample of 180 post-menopausal women will be randomly assigned to either a 5-session Hypnosis Intervention or 5-session structured-attention control with 12 week follow-up. The present study will compare hypnosis to a structured-attention control in reducing hot flashes (perceived and physiologically monitored) in post-menopausal women in a randomized clinical trial. Outcomes will be hot flashes (self-report daily diaries; physiological monitoring; Hot Flash Related Daily Interference Scale), anxiety (State-Trait Anxiety Inventory; Hospital Anxiety and Depression Scale (HADS); anxiety visual analog scale (VAS rating); depression (Center for Epidemiologic Studies Depression Scale), sexual functioning (Sexual Activity Questionnaire), sleep quality (Pittsburgh Sleep Quality Index) and cortisol.</p> <p>Discussion</p> <p>This study will be the first full scale test of hypnosis for hot flashes; one of the first studies to examine both perceived impact and physiologically measured impact of a mind-body intervention for hot flashes using state-of-the-art 24 hour ambulatory physiological monitoring; the first study to examine the effect of hypnosis for hot flashes on cortisol; and the first investigation of the role of cognitive expectancies in treatment of hot flashes in comparison to a Structured-Attention Control.</p> <p>Trial Registration</p> <p>This clinical trial has been registered with ClinicalTrials.gov, a service of the U.S. National Institutes of Health, ClinicalTrials.gov Identifier: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01293695">NCT01293695</a>.</p
A Herpesvirus Encoded Deubiquitinase Is a Novel Neuroinvasive Determinant
The neuroinvasive property of several alpha-herpesviruses underlies an uncommon infectious process that includes the establishment of life-long latent infections in sensory neurons of the peripheral nervous system. Several herpesvirus proteins are required for replication and dissemination within the nervous system, indicating that exploiting the nervous system as a niche for productive infection requires a specialized set of functions encoded by the virus. Whether initial entry into the nervous system from peripheral tissues also requires specialized viral functions is not known. Here we show that a conserved deubiquitinase domain embedded within a pseudorabies virus structural protein, pUL36, is essential for initial neural invasion, but is subsequently dispensable for transmission within and between neurons of the mammalian nervous system. These findings indicate that the deubiquitinase contributes to neurovirulence by participating in a previously unrecognized initial step in neuroinvasion
Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV
The azimuthal anisotropy of charged particles in PbPb collisions at
nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS
detector at the LHC over an extended transverse momentum (pt) range up to
approximately 60 GeV. The data cover both the low-pt region associated with
hydrodynamic flow phenomena and the high-pt region where the anisotropies may
reflect the path-length dependence of parton energy loss in the created medium.
The anisotropy parameter (v2) of the particles is extracted by correlating
charged tracks with respect to the event-plane reconstructed by using the
energy deposited in forward-angle calorimeters. For the six bins of collision
centrality studied, spanning the range of 0-60% most-central events, the
observed v2 values are found to first increase with pt, reaching a maximum
around pt = 3 GeV, and then to gradually decrease to almost zero, with the
decline persisting up to at least pt = 40 GeV over the full centrality range
measured.Comment: Replaced with published version. Added journal reference and DO
X-ray emission from the Sombrero galaxy: discrete sources
We present a study of discrete X-ray sources in and around the
bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival
Chandra observations with a total exposure of ~200 ks. With a detection limit
of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30
kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler
et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS
observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray
binaries (LMXBs). We quantify the differential luminosity functions (LFs) for
both the detected GC and field LMXBs, whose power-low indices (~1.1 for the
GC-LF and ~1.6 for field-LF) are consistent with previous studies for
elliptical galaxies. With precise sky positions of the GCs without a detected
X-ray source, we further quantify, through a fluctuation analysis, the GC LF at
fainter luminosities down to 1E35 erg/s. The derived index rules out a
faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent
findings in several elliptical galaxies and the bulge of M31. On the other
hand, the 2-6 keV unresolved emission places a tight constraint on the field
LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101
sources in the halo of Sombrero. The presence of these sources cannot be
interpreted as galactic LMXBs whose spatial distribution empirically follows
the starlight. Their number is also higher than the expected number of cosmic
AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray
surveys. We suggest that either the cosmic X-ray background is unusually high
in the direction of Sombrero, or a distinct population of X-ray sources is
present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres
Study of CP violation in Dalitz-plot analyses of B0 --> K+K-KS, B+ --> K+K-K+, and B+ --> KSKSK+
We perform amplitude analyses of the decays , , and , and measure CP-violating
parameters and partial branching fractions. The results are based on a data
sample of approximately decays, collected with the
BABAR detector at the PEP-II asymmetric-energy factory at the SLAC National
Accelerator Laboratory. For , we find a direct CP asymmetry
in of , which differs
from zero by . For , we measure the
CP-violating phase .
For , we measure an overall direct CP asymmetry of
. We also perform an angular-moment analysis of
the three channels, and determine that the state can be described
well by the sum of the resonances , , and
.Comment: 35 pages, 68 postscript figures. v3 - minor modifications to agree
with published versio
Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy
A search for new physics is performed in events with two same-sign isolated
leptons, hadronic jets, and missing transverse energy in the final state. The
analysis is based on a data sample corresponding to an integrated luminosity of
4.98 inverse femtobarns produced in pp collisions at a center-of-mass energy of
7 TeV collected by the CMS experiment at the LHC. This constitutes a factor of
140 increase in integrated luminosity over previously published results. The
observed yields agree with the standard model predictions and thus no evidence
for new physics is found. The observations are used to set upper limits on
possible new physics contributions and to constrain supersymmetric models. To
facilitate the interpretation of the data in a broader range of new physics
scenarios, information on the event selection, detector response, and
efficiencies is provided.Comment: Published in Physical Review Letter
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