228 research outputs found
Eficacia del implante de células mononucleares autólogas en el tratamiento de la periodontitis crónica
Introducción: Los buenos resultados en la regeneración de tejidos mediante la implantación de células mononucleares en distintas especialidades médicas en el mundo y en Cuba, ha motivado a considerar el periodonto como candidato para esta terapia. Objetivo: Determinar la eficacia del implante de células mononucleares autólogas en el tratamiento de la periodontitis crónica a 48 meses de evolución. Material y Métodos: Se realizó un ensayo clínico fase III, aleatorizado y controlado en pacientes con periodontitis crónica durante los años 2008 a 2014. De ese grupo de pacientes se evaluaron 30 que tenían 48 ó más meses de recibir tratamiento en la consulta de Periodoncia del Hospital “Enrique Cabrera” en el período comprendido de febrero a mayo de 2015; 15 habían recibido tratamiento con células mononucleares (grupo estudio) y 15 terapia convencional (grupo control). La movilización a la sangre periférica de las células mononucleares se realizó mediante la aplicación del factor estimulador de colonias de granulocitos (FEC-G). Resultados: Se aprecia una disminución del promedio de todas las variables clínicas, que es marcada en cada uno de los períodos evolutivos con respecto al estado inicial de los pacientes a los 6, 12, 36 y 48 meses posteriores al tratamiento en el grupo de estudio, mientras que en el control las manifestaciones de la enfermedad fueron reapareciendo paulatinamente a medida que avanzaba el tiempo post-tratamiento. Estos resultados fueron significativos. Conclusiones: La terapia celular regenerativa con células mononucleares autólogas es eficaz para el tratamiento de pacientes con periodontitis y su efecto es prolongado. Palabras clave: Periodontitis, terapia celular, células madre, regeneración periodontal, células mononucleares autólogas. ABSTRACTIntroduction: Over the last years, in Cuba and other countries, encouraging results have been obtained in different medical specialties in the field of tissue regeneration by implanting stem cells; it has motivated us to consider periodontal tissue as a target for this therapy. Objective: To determine the efficacy of the implant of mononuclear autologous cells for the treatment of 48 months evolution chronic periodontitis. Material and Methods: 30 patients attending the Periodontology Clinic of the “Enrique Cabrera” hospital for over48 months during years 2008 to 2014 where included in the study, divided into two groups 15 patients each: group A were treated with autologous mononuclear cells and group B, who underwent classic therapy. The peripheral blood autologous mononuclear cells (MNC-SP) were mobilized with granulocyte colony- stimulating factor (G-CSF). Results: Group A patients showed a significant average decrease in all clinical variables, more remarkable in every of the evolution periods as compared to the initial stage of every patient at 6, 12, 24 and 48 months after starting the treatment. In Group B patients, signs of the disease gradually reappeared as the post-treatment period proceeded. Conclusions: Regenerative cell therapy with MNC-SP is effective and long lasting in patients with periodontitis.Keywords: Periodontitis, cell therapy, stem cells, periodontal regeneration, bone marrow mononuclear cells.</p
A Joint Search for Gravitational Wave Bursts with AURIGA and LIGO
The first simultaneous operation of the AURIGA detector and the LIGO
observatory was an opportunity to explore real data, joint analysis methods
between two very different types of gravitational wave detectors: resonant bars
and interferometers. This paper describes a coincident gravitational wave burst
search, where data from the LIGO interferometers are cross-correlated at the
time of AURIGA candidate events to identify coherent transients. The analysis
pipeline is tuned with two thresholds, on the signal-to-noise ratio of AURIGA
candidate events and on the significance of the cross-correlation test in LIGO.
The false alarm rate is estimated by introducing time shifts between data sets
and the network detection efficiency is measured with simulated signals with
power in the narrower AURIGA band. In the absence of a detection, we discuss
how to set an upper limit on the rate of gravitational waves and to interpret
it according to different source models. Due to the short amount of analyzed
data and to the high rate of non-Gaussian transients in the detectors noise at
the time, the relevance of this study is methodological: this was the first
joint search for gravitational wave bursts among detectors with such different
spectral sensitivity and the first opportunity for the resonant and
interferometric communities to unify languages and techniques in the pursuit of
their common goal.Comment: 18 pages, IOP, 12 EPS figure
Swift follow-up observations of candidate gravitational-wave transient events
We present the first multi-wavelength follow-up observations of two candidate
gravitational-wave (GW) transient events recorded by LIGO and Virgo in their
2009-2010 science run. The events were selected with low latency by the network
of GW detectors and their candidate sky locations were observed by the Swift
observatory. Image transient detection was used to analyze the collected
electromagnetic data, which were found to be consistent with background.
Off-line analysis of the GW data alone has also established that the selected
GW events show no evidence of an astrophysical origin; one of them is
consistent with background and the other one was a test, part of a "blind
injection challenge". With this work we demonstrate the feasibility of rapid
follow-ups of GW transients and establish the sensitivity improvement joint
electromagnetic and GW observations could bring. This is a first step toward an
electromagnetic follow-up program in the regime of routine detections with the
advanced GW instruments expected within this decade. In that regime
multi-wavelength observations will play a significant role in completing the
astrophysical identification of GW sources. We present the methods and results
from this first combined analysis and discuss its implications in terms of
sensitivity for the present and future instruments.Comment: Submitted for publication 2012 May 25, accepted 2012 October 25,
published 2012 November 21, in ApJS, 203, 28 (
http://stacks.iop.org/0067-0049/203/28 ); 14 pages, 3 figures, 6 tables;
LIGO-P1100038; Science summary at
http://www.ligo.org/science/Publication-S6LVSwift/index.php ; Public access
area to figures, tables at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p110003
A First Search for coincident Gravitational Waves and High Energy Neutrinos using LIGO, Virgo and ANTARES data from 2007
We present the results of the first search for gravitational wave bursts
associated with high energy neutrinos. Together, these messengers could reveal
new, hidden sources that are not observed by conventional photon astronomy,
particularly at high energy. Our search uses neutrinos detected by the
underwater neutrino telescope ANTARES in its 5 line configuration during the
period January - September 2007, which coincided with the fifth and first
science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed
for candidate gravitational-wave signals coincident in time and direction with
the neutrino events. No significant coincident events were observed. We place
limits on the density of joint high energy neutrino - gravitational wave
emission events in the local universe, and compare them with densities of
merger and core-collapse events.Comment: 19 pages, 8 figures, science summary page at
http://www.ligo.org/science/Publication-S5LV_ANTARES/index.php. Public access
area to figures, tables at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p120000
Search for Gravitational Waves from Low Mass Compact Binary Coalescence in LIGO's Sixth Science Run and Virgo's Science Runs 2 and 3
We report on a search for gravitational waves from coalescing compact
binaries using LIGO and Virgo observations between July 7, 2009 and October 20,
2010. We searched for signals from binaries with total mass between 2 and 25
solar masses; this includes binary neutron stars, binary black holes, and
binaries consisting of a black hole and neutron star. The detectors were
sensitive to systems up to 40 Mpc distant for binary neutron stars, and further
for higher mass systems. No gravitational-wave signals were detected. We report
upper limits on the rate of compact binary coalescence as a function of total
mass, including the results from previous LIGO and Virgo observations. The
cumulative 90%-confidence rate upper limits of the binary coalescence of binary
neutron star, neutron star- black hole and binary black hole systems are 1.3 x
10^{-4}, 3.1 x 10^{-5} and 6.4 x 10^{-6} Mpc^{-3}yr^{-1}, respectively. These
upper limits are up to a factor 1.4 lower than previously derived limits. We
also report on results from a blind injection challenge.Comment: 11 pages, 5 figures. For a repository of data used in the
publication, go to:
. Also see the
announcement for this paper on ligo.org at:
<http://www.ligo.org/science/Publication-S6CBCLowMass/index.php
Implementation and testing of the first prompt search for gravitational wave transients with electromagnetic counterparts
Aims. A transient astrophysical event observed in both gravitational wave
(GW) and electromagnetic (EM) channels would yield rich scientific rewards. A
first program initiating EM follow-ups to possible transient GW events has been
developed and exercised by the LIGO and Virgo community in association with
several partners. In this paper, we describe and evaluate the methods used to
promptly identify and localize GW event candidates and to request images of
targeted sky locations.
Methods. During two observing periods (Dec 17 2009 to Jan 8 2010 and Sep 2 to
Oct 20 2010), a low-latency analysis pipeline was used to identify GW event
candidates and to reconstruct maps of possible sky locations. A catalog of
nearby galaxies and Milky Way globular clusters was used to select the most
promising sky positions to be imaged, and this directional information was
delivered to EM observatories with time lags of about thirty minutes. A Monte
Carlo simulation has been used to evaluate the low-latency GW pipeline's
ability to reconstruct source positions correctly.
Results. For signals near the detection threshold, our low-latency algorithms
often localized simulated GW burst signals to tens of square degrees, while
neutron star/neutron star inspirals and neutron star/black hole inspirals were
localized to a few hundred square degrees. Localization precision improves for
moderately stronger signals. The correct sky location of signals well above
threshold and originating from nearby galaxies may be observed with ~50% or
better probability with a few pointings of wide-field telescopes.Comment: 17 pages. This version (v2) includes two tables and 1 section not
included in v1. Accepted for publication in Astronomy & Astrophysic
First Low-Latency LIGO+Virgo Search for Binary Inspirals and their Electromagnetic Counterparts
Aims. The detection and measurement of gravitational-waves from coalescing
neutron-star binary systems is an important science goal for ground-based
gravitational-wave detectors. In addition to emitting gravitational-waves at
frequencies that span the most sensitive bands of the LIGO and Virgo detectors,
these sources are also amongst the most likely to produce an electromagnetic
counterpart to the gravitational-wave emission. A joint detection of the
gravitational-wave and electromagnetic signals would provide a powerful new
probe for astronomy.
Methods. During the period between September 19 and October 20, 2010, the
first low-latency search for gravitational-waves from binary inspirals in LIGO
and Virgo data was conducted. The resulting triggers were sent to
electromagnetic observatories for followup. We describe the generation and
processing of the low-latency gravitational-wave triggers. The results of the
electromagnetic image analysis will be described elsewhere.
Results. Over the course of the science run, three gravitational-wave
triggers passed all of the low-latency selection cuts. Of these, one was
followed up by several of our observational partners. Analysis of the
gravitational-wave data leads to an estimated false alarm rate of once every
6.4 days, falling far short of the requirement for a detection based solely on
gravitational-wave data.Comment: 13 pages, 13 figures. For a repository of data used in the
publication, go to:
http://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=P1100065 Also see the
announcement for this paper on ligo.org at:
http://www.ligo.org/science/Publication-S6CBCLowLatency
Einstein@Home all-sky search for periodic gravitational waves in LIGO S5 data
This paper presents results of an all-sky searches for periodic gravitational
waves in the frequency range [50, 1190] Hz and with frequency derivative ranges
of [-2 x 10^-9, 1.1 x 10^-10] Hz/s for the fifth LIGO science run (S5). The
novelty of the search lies in the use of a non-coherent technique based on the
Hough-transform to combine the information from coherent searches on timescales
of about one day. Because these searches are very computationally intensive,
they have been deployed on the Einstein@Home distributed computing project
infrastructure. The search presented here is about a factor 3 more sensitive
than the previous Einstein@Home search in early S5 LIGO data. The
post-processing has left us with eight surviving candidates. We show that
deeper follow-up studies rule each of them out. Hence, since no statistically
significant gravitational wave signals have been detected, we report upper
limits on the intrinsic gravitational wave amplitude h0. For example, in the
0.5 Hz-wide band at 152.5 Hz, we can exclude the presence of signals with h0
greater than 7.6 x 10^-25 with a 90% confidence level.Comment: 29 pages, 14 figures, 6 tables. Science summary page at
http://www.ligo.org/science/Publication-FullS5EatH/index.php ; Public access
area to figures and tables at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p120002
Multimessenger Search for Sources of Gravitational Waves and High-Energy Neutrinos: Results for Initial LIGO-Virgo and IceCube
We report the results of a multimessenger search for coincident signals from
the LIGO and Virgo gravitational-wave observatories and the partially completed
IceCube high-energy neutrino detector, including periods of joint operation
between 2007-2010. These include parts of the 2005-2007 run and the 2009-2010
run for LIGO-Virgo, and IceCube's observation periods with 22, 59 and 79
strings. We find no significant coincident events, and use the search results
to derive upper limits on the rate of joint sources for a range of source
emission parameters. For the optimistic assumption of gravitational-wave
emission energy of \,Mc at \,Hz with \,ms duration, and high-energy neutrino emission of \,erg
comparable to the isotropic gamma-ray energy of gamma-ray bursts, we limit the
source rate below \,Mpcyr. We also examine
how combining information from gravitational waves and neutrinos will aid
discovery in the advanced gravitational-wave detector era
Sensitivity Achieved by the LIGO and Virgo Gravitational Wave Detectors during LIGO's Sixth and Virgo's Second and Third Science Runs
We summarize the sensitivity achieved by the LIGO and Virgo gravitational wave detectors for low-mass compact binary coalescence (CBC) searches during LIGO's sixth science run and Virgo's second and third science runs. We present strain noise power spectral densities (PSDs) which are representative of the typical performance achieved by the detectors in these science runs. The data presented here and in the accompanying web-accessible data files are intended to be released to the public as a summary of detector performance for low-mass CBC searches during S6 and VSR2-3
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