2,488 research outputs found
Holographic equations of state and astrophysical compact objects
We solve the Tolman-Oppenheimer-Volkoff equation using an equation of state
(EoS) calculated in holographic QCD. The aim is to use compact astrophysical
objects like neutron stars as an indicator to test holographic equations of
state. We first try an EoS from a dense D4/D8/\textoverline {D8} model. In this
case, however, we could not find a stable compact star, a star satisfying
pressure-zero condition with a radius , , within a reasonable value
of the radius. This means that the EoS from the D4/D8/\textoverline {D8} model
may not support any stable compact stars or may support one whose radius is
very large. This might be due to a deficit of attractive force from a scalar
field or two-pion exchange in the D4/D8/\textoverline {D8} model. Then, we
consider D4/D6 type models with different number of quark flavors, .
Though the mass and radius of a holographic star is larger than those of normal
neutron stars, the D4/D6 type EoS renders a stable compact star.Comment: 12 pages, 9 figure
Efficacy and safety of raltegravir for treatment of HIV for 5 years in the BENCHMRK studies: Final results of two randomised, placebo-controlled trials
BACKGROUND:
Two randomised, placebo-controlled trials-BENCHMRK-1 and BENCHMRK-2-investigated the efficacy and safety of raltegravir, an HIV-1 integrase strand-transfer inhibitor. We report final results of BENCHMRK-1 and BENCHMRK-2 combined at 3 years (the end of the double-blind phase) and 5 years (the end of the study).
METHODS:
Integrase-inhibitor-naive patients with HIV resistant to three classes of drug and who were failing antiretroviral therapy were enrolled. Patients were randomly assigned (2:1) to raltegravir 400 mg twice daily or placebo, both with optimised background treatment. Patients and investigators were masked to treatment allocation until week 156, after which all patients were offered open-label raltegravir until week 240. The primary endpoint was previously assessed at 16 weeks. We assessed long-term efficacy with endpoints of the proportion of patients with an HIV viral load of less than 50 copies per mL and less than 400 copies per mL, and mean change in CD4 cell count, at weeks 156 and 240.
FINDINGS:
1012 patients were screened for inclusion. 462 were treated with raltegravir and 237 with placebo. At week 156, 51% in the raltegravir group versus 22% in the placebo group (non-completer classed as failure) had viral loads of less than 50 copies per mL, and 54% versus 23% had viral loads of less than 400 copies per mL. Mean CD4 cell count increase (analysed by an observed failure approach) was 164 cells per μL versus 63 cells per μL. After week 156, 251 patients (54%) from the raltegravir group and 47 (20%) from the placebo group entered the open-label raltergravir phase; 221 (47%) versus 44 (19%) completed the entire study. At week 240, viral load was less than 50 copies per mL in 193 (42%) of all patients initially assigned to raltegravir and less than 400 copies per mL in 210 (45%); mean CD4 cell count increased by 183 cells per μL. Virological failure occurred in 166 raltegravir recipients (36%) during the double-blind phase and in 17 of all patients (6%) during the open-label phase. The most common drug-related adverse events at 5 years in both groups were nausea, headache, and diarrhoea, and occurred in similar proportions in each group. Laboratory test results were similar in both treatment groups and showed little change after year 2.
INTERPRETATION:
Raltegravir has a favourable long-term efficacy and safety profile in integrase-inhibitor-naive patients with triple-class resistant HIV in whom antiretroviral therapy is failing. Raltegravir is an alternative for treatment-experienced patients, particularly those with few treatment options
Identification of Giardia lamblia DHHC Proteins and the Role of Protein S-palmitoylation in the Encystation Process
Protein S-palmitoylation, a hydrophobic post-translational modification, is performed by protein acyltransferases that have a common DHHC Cys-rich domain (DHHC proteins), and provides a regulatory switch for protein membrane association. In this work, we analyzed the presence of DHHC proteins in the protozoa parasite Giardia lamblia and the function of the reversible S-palmitoylation of proteins during parasite differentiation into cyst. Two specific events were observed: encysting cells displayed a larger amount of palmitoylated proteins, and parasites treated with palmitoylation inhibitors produced a reduced number of mature cysts. With bioinformatics tools, we found nine DHHC proteins, potential protein acyltransferases, in the Giardia proteome. These proteins displayed a conserved structure when compared to different organisms and are distributed in different monophyletic clades. Although all Giardia DHHC proteins were found to be present in trophozoites and encysting cells, these proteins showed a different intracellular localization in trophozoites and seemed to be differently involved in the encystation process when they were overexpressed. dhhc transgenic parasites showed a different pattern of cyst wall protein expression and yielded different amounts of mature cysts when they were induced to encyst. Our findings disclosed some important issues regarding the role of DHHC proteins and palmitoylation during Giardia encystation.Fil: Merino, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Zamponi, Nahuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Vranych, Cecilia Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Touz, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Ropolo, Andrea Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentin
Physical therapy intervention studies on idiopathic scoliosis-review with the focus on inclusion criteria1
<p>Abstract</p> <p>Background</p> <p>Studies investigating the outcome of conservative scoliosis treatment differ widely with respect to the inclusion criteria used. This study has been performed to investigate the possibility to find useful inclusion criteria for future prospective studies on physiotherapy (PT).</p> <p>Materials and methods</p> <p>A PubMed search for outcome papers on PT was performed in order to detect study designs and inclusion criteria used.</p> <p>Results</p> <p>Real outcome papers (start of treatment in immature samples/end results after the end of growth; controlled studies in adults with scoliosis with a follow-up of more than 5 years) have not been found. Some papers investigated mid-term effects of exercises, most were retrospective, few prospective and many included patient samples with questionable treatment indications.</p> <p>Conclusion</p> <p>There is no outcome paper on PT in scoliosis with a patient sample at risk for being progressive in adults or in adolescents followed from premenarchial status until skeletal maturity. However, papers on bracing are more frequently found and bracing can be regarded as evidence-based in the conservative management and rehabilitation of idiopathic scoliosis in adolescents.</p
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
Measurement of the Z/gamma* + b-jet cross section in pp collisions at 7 TeV
The production of b jets in association with a Z/gamma* boson is studied
using proton-proton collisions delivered by the LHC at a centre-of-mass energy
of 7 TeV and recorded by the CMS detector. The inclusive cross section for
Z/gamma* + b-jet production is measured in a sample corresponding to an
integrated luminosity of 2.2 inverse femtobarns. The Z/gamma* + b-jet cross
section with Z/gamma* to ll (where ll = ee or mu mu) for events with the
invariant mass 60 < M(ll) < 120 GeV, at least one b jet at the hadron level
with pT > 25 GeV and abs(eta) < 2.1, and a separation between the leptons and
the jets of Delta R > 0.5 is found to be 5.84 +/- 0.08 (stat.) +/- 0.72 (syst.)
+(0.25)/-(0.55) (theory) pb. The kinematic properties of the events are also
studied and found to be in agreement with the predictions made by the MadGraph
event generator with the parton shower and the hadronisation performed by
PYTHIA.Comment: Submitted to the Journal of High Energy Physic
Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV
A search for new physics is presented based on an event signature of at least
three jets accompanied by large missing transverse momentum, using a data
sample corresponding to an integrated luminosity of 36 inverse picobarns
collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector
at the LHC. No excess of events is observed above the expected standard model
backgrounds, which are all estimated from the data. Exclusion limits are
presented for the constrained minimal supersymmetric extension of the standard
model. Cross section limits are also presented using simplified models with new
particles decaying to an undetected particle and one or two jets
Combined search for the quarks of a sequential fourth generation
Results are presented from a search for a fourth generation of quarks
produced singly or in pairs in a data set corresponding to an integrated
luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in
2011. A novel strategy has been developed for a combined search for quarks of
the up and down type in decay channels with at least one isolated muon or
electron. Limits on the mass of the fourth-generation quarks and the relevant
Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a
simple extension of the standard model with a sequential fourth generation of
fermions. The existence of mass-degenerate fourth-generation quarks with masses
below 685 GeV is excluded at 95% confidence level for minimal off-diagonal
mixing between the third- and the fourth-generation quarks. With a mass
difference of 25 GeV between the quark masses, the obtained limit on the masses
of the fourth-generation quarks shifts by about +/- 20 GeV. These results
significantly reduce the allowed parameter space for a fourth generation of
fermions.Comment: Replaced with published version. Added journal reference and DO
Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV
The t t-bar production cross section (sigma[t t-bar]) is measured in
proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS
experiment, corresponding to an integrated luminosity of 2.3 inverse
femtobarns. The measurement is performed in events with two leptons (electrons
or muons) in the final state, at least two jets identified as jets originating
from b quarks, and the presence of an imbalance in transverse momentum. The
measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/-
2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction
of the standard model.Comment: Replaced with published version. Included journal reference and DO
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