87 research outputs found
Inflammatory and haematological markers in the maternal, umbilical cord and infant circulation in histological chorioamnionitis
BACKGROUND: The relationship between histological chorioamnionitis and haematological and biochemical markers in mothers and infants at delivery, and in infants postnatally, is incompletely characterised. These markers are widely used in the diagnosis of maternal and neonatal infection. Our objective was to investigate the effects of histological chorioamnionitis (HCA) on haematological and biochemical inflammatory markers in mothers and infants at delivery, and in infants post-delivery. METHODS: Two hundred and forty seven mothers, delivering 325 infants, were recruited at the only tertiary perinatal centre in Western Australia. Placentae were assessed for evidence of HCA using a semi-quantitative scoring system. Maternal high sensitivity C-reactive protein (hsCRP), procalcitonin, and umbilical cord hsCRP, procalcitonin, white cell count and absolute neutrophil count were measured at delivery. In infants where sepsis was clinically suspected, postnatal CRP, white cell count and absolute neutrophil count were measured up to 48 hours of age. The effect of HCA on maternal, cord and neonatal markers was evaluated by multivariable regression analysis. RESULTS: The median gestational age was 34 weeks and HCA was present in 26 of 247 (10.5%) placentae. Mothers whose pregnancies were complicated by HCA had higher hsCRP (median 26 (range 2-107) versus 5.6 (0-108) mg/L; P<0.001). Histological chorioamnionitis was associated with higher umbilical cord hsCRP (75(th) percentile 2.91 mg/L (range 0-63.9) versus 75(th) percentile 0 mg/L (0-45.6); P<0.001) and procalcitonin (median 0.293 (range 0.05-27.37) versus median 0.064 (range 0.01-5.24) ug/L; P<0.001), with a sustained increase in neonatal absolute neutrophil count (median 4.5 (0.1-26.4)x10(9)/L versus 3.0 (0.1-17.8)x10(9)/L), and CRP up to 48 hours post-partum (median 10 versus 6.5 mg/L) (P<0.05 for each). CONCLUSION: Histological chorioamnionitis is associated with modest systemic inflammation in maternal and cord blood. These systemic changes may increase postnatally, potentially undermining their utility in the diagnosis of early-onset neonatal infection
A simulation model approach to analysis of the business case for eliminating health care disparities
<p>Abstract</p> <p>Background</p> <p>Purchasers can play an important role in eliminating racial and ethnic disparities in health care. A need exists to develop a compelling "business case" from the employer perspective to put, and keep, the issue of racial/ethnic disparities in health care on the quality improvement agenda for health plans and providers.</p> <p>Methods</p> <p>To illustrate a method for calculating an employer business case for disparity reduction and to compare the business case in two clinical areas, we conducted analyses of the direct (medical care costs paid by employers) and indirect (absenteeism, productivity) effects of eliminating known racial/ethnic disparities in mammography screening and appropriate medication use for patients with asthma. We used Markov simulation models to estimate the consequences, for defined populations of African-American employees or health plan members, of a 10% increase in HEDIS mammography rates or a 10% increase in appropriate medication use among either adults or children/adolescents with asthma.</p> <p>Results</p> <p>The savings per employed African-American woman aged 50-65 associated with a 10% increase in HEDIS mammography rate, from direct medical expenses and indirect costs (absenteeism, productivity) combined, was 1,660 per person if raising medication adherence rates in African-American employees or dependents by 10%.</p> <p>Conclusions</p> <p>For the employer business case, both clinical scenarios modeled showed positive results. There is a greater potential financial gain related to eliminating a disparity in asthma medications than there is for eliminating a disparity in mammography rates.</p
Partner randomized controlled trial: study protocol and coaching intervention
<p>Abstract</p> <p>Background</p> <p>Many children with asthma live with frequent symptoms and activity limitations, and visits for urgent care are common. Many pediatricians do not regularly meet with families to monitor asthma control, identify concerns or problems with management, or provide self-management education. Effective interventions to improve asthma care such as small group training and care redesign have been difficult to disseminate into office practice.</p> <p>Methods and design</p> <p>This paper describes the protocol for a randomized controlled trial (RCT) to evaluate a 12-month telephone-coaching program designed to support primary care management of children with persistent asthma and subsequently to improve asthma control and disease-related quality of life and reduce urgent care events for asthma care. Randomization occurred at the practice level with eligible families within a practice having access to the coaching program or to usual care. The coaching intervention was based on the transtheoretical model of behavior change. Targeted behaviors included 1) effective use of controller medications, 2) effective use of rescue medications and 3) monitoring to ensure optimal control. Trained lay coaches provided parents with education and support for asthma care, tailoring the information provided and frequency of contact to the parent's readiness to change their child's day-to-day asthma management. Coaching calls varied in frequency from weekly to monthly. For each participating family, follow-up measurements were obtained at 12- and 24-months after enrollment in the study during a telephone interview.</p> <p>The primary outcomes were the mean change in 1) the child's asthma control score, 2) the parent's quality of life score, and 3) the number of urgent care events assessed at 12 and 24 months. Secondary outcomes reflected adherence to guideline recommendations by the primary care pediatricians and included the proportion of children prescribed controller medications, having maintenance care visits at least twice a year, and an asthma action plan. Cost-effectiveness of the intervention was also measured.</p> <p>Discussion</p> <p>Twenty-two practices (66 physicians) were randomized (11 per treatment group), and 950 families with a child 3-12 years old with persistent asthma were enrolled. A description of the coaching intervention is presented.</p> <p>Trial registration</p> <p>ClinicalTrials.gov identifier <a href="http://www.clinicaltrials.gov/ct2/show/NCT00860834">NCT00860834</a>.</p
A theoretical model of inflammation- and mechanotransduction- driven asthmatic airway remodelling
Inflammation, airway hyper-responsiveness and airway remodelling are well-established hallmarks of asthma, but their inter-relationships remain elusive. In order to obtain a better understanding of their inter-dependence, we develop a mechanochemical morphoelastic model of the airway wall accounting for local volume changes in airway smooth muscle (ASM) and extracellular matrix in response to transient inflammatory or contractile agonist challenges. We use constrained mixture theory, together with a multiplicative decomposition of growth from the elastic deformation, to model the airway wall as a nonlinear fibre-reinforced elastic cylinder. Local contractile agonist drives ASM cell contraction, generating mechanical stresses in the tissue that drive further release of mitogenic mediators and contractile agonists via underlying mechanotransductive signalling pathways. Our model predictions are consistent with previously described inflammation-induced remodelling within an axisymmetric airway geometry. Additionally, our simulations reveal novel mechanotransductive feedback by which hyper-responsive airways exhibit increased remodelling, for example, via stress-induced release of pro-mitogenic and procontractile cytokines. Simulation results also reveal emergence of a persistent contractile tone observed in asthmatics, via either a pathological mechanotransductive feedback loop, a failure to clear agonists from the tissue, or a combination of both. Furthermore, we identify various parameter combinations that may contribute to the existence of different asthma phenotypes, and we illustrate a combination of factors which may predispose severe asthmatics to fatal bronchospasms
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
All-sky search for continuous gravitational waves from isolated neutron stars in the early O3 LIGO data
We report on an all-sky search for continuous gravitational waves in the frequency band 20-2000 Hz and with a frequency time derivative in the range of [-1.0,+0.1]×10-8 Hz/s. Such a signal could be produced by a nearby, spinning and slightly nonaxisymmetric isolated neutron star in our Galaxy. This search uses the LIGO data from the first six months of Advanced LIGO's and Advanced Virgo's third observational run, O3. No periodic gravitational wave signals are observed, and 95% confidence-level (C.L.) frequentist upper limits are placed on their strengths. The lowest upper limits on worst-case (linearly polarized) strain amplitude h0 are ∼1.7×10-25 near 200 Hz. For a circularly polarized source (most favorable orientation), the lowest upper limits are ∼6.3×10-26. These strict frequentist upper limits refer to all sky locations and the entire range of frequency derivative values. For a population-averaged ensemble of sky locations and stellar orientations, the lowest 95% C.L. upper limits on the strain amplitude are ∼1.4×10-25. These upper limits improve upon our previously published all-sky results, with the greatest improvement (factor of ∼2) seen at higher frequencies, in part because quantum squeezing has dramatically improved the detector noise level relative to the second observational run, O2. These limits are the most constraining to date over most of the parameter space searched
Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model
We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society
Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model
We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO’s second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h95%0=3.47×10−25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering
Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A
On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB 170817A and GW170817 occurring by chance is . We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB 170817A provides new insight into fundamental physics and the origin of short GRBs. We use the observed time delay of between GRB 170817A and GW170817 to: (i) constrain the difference between the speed of gravity and the speed of light to be between and times the speed of light, (ii) place new bounds on the violation of Lorentz invariance, (iii) present a new test of the equivalence principle by constraining the Shapiro delay between gravitational and electromagnetic radiation. We also use the time delay to constrain the size and bulk Lorentz factor of the region emitting the gamma-rays. GRB 170817A is the closest short GRB with a known distance, but is between 2 and 6 orders of magnitude less energetic than other bursts with measured redshift. A new generation of gamma-ray detectors, and subthreshold searches in existing detectors, will be essential to detect similar short bursts at greater distances. Finally, we predict a joint detection rate for the Fermi Gamma-ray Burst Monitor and the Advanced LIGO and Virgo detectors of 0.1-1.4 per year during the 2018-2019 observing run and 0.3-1.7 per year at design sensitivity
All-sky, all-frequency directional search for persistent gravitational waves from Advanced LIGO’s and Advanced Virgo’s first three observing runs
We present the first results from an all-sky all-frequency (ASAF) search for
an anisotropic stochastic gravitational-wave background using the data from the
first three observing runs of the Advanced LIGO and Advanced Virgo detectors.
Upper limit maps on broadband anisotropies of a persistent stochastic
background were published for all observing runs of the LIGO-Virgo detectors.
However, a broadband analysis is likely to miss narrowband signals as the
signal-to-noise ratio of a narrowband signal can be significantly reduced when
combined with detector output from other frequencies. Data folding and the
computationally efficient analysis pipeline, {\tt PyStoch}, enable us to
perform the radiometer map-making at every frequency bin. We perform the search
at 3072 {\tt{HEALPix}} equal area pixels uniformly tiling the sky and in every
frequency bin of width ~Hz in the range ~Hz, except for bins
that are likely to contain instrumental artefacts and hence are notched. We do
not find any statistically significant evidence for the existence of narrowband
gravitational-wave signals in the analyzed frequency bins. Therefore, we place
confidence upper limits on the gravitational-wave strain for each
pixel-frequency pair, the limits are in the range . In addition, we outline a method to identify candidate
pixel-frequency pairs that could be followed up by a more sensitive (and
potentially computationally expensive) search, e.g., a matched-filtering-based
analysis, to look for fainter nearly monochromatic coherent signals. The ASAF
analysis is inherently independent of models describing any spectral or spatial
distribution of power. We demonstrate that the ASAF results can be
appropriately combined over frequencies and sky directions to successfully
recover the broadband directional and isotropic results
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