365 research outputs found
Performance of screening for aneuploidies by cell-free DNA analysis of maternal blood in twin pregnancies
Objectives
To report clinical implementation of cell‐free DNA (cfDNA) analysis of maternal blood in screening for trisomies 21, 18 and 13 in twin pregnancies and examine variables that could influence the failure rate of the test.
Methods
cfDNA testing was performed in 515 twin pregnancies at 10–28 weeks' gestation. The failure rate of the test to provide results was compared with that in 1847 singleton pregnancies, and logistic regression analysis was used to determine which factors among maternal and pregnancy characteristics were significant predictors of test failure.
Results
Failure rate of the cfDNA test at first sampling was 1.7% in singletons and 5.6% in twins. Of those with a test result, the median fetal fraction in twins was 8.7% (range, 4.1–30.0%), which was lower than that in singletons (11.7% (range, 4.0–38.9%)). Multivariable regression analysis demonstrated that twin pregnancy, higher maternal weight and conception by in‐vitro fertilization provided significant independent prediction of test failure. Follow‐up was available in 351 (68.2%) of the twin pregnancies and comprised 334 with euploid fetuses, 12 discordant for trisomy 21 and five discordant for trisomy 18. In all 323 euploid cases with a result, the risk score for each trisomy was < 1:10 000. In 11 of the 12 cases with trisomy 21 and in the five with trisomy 18, the cfDNA test gave a high‐risk result, but in one case of trisomy 21, the score was < 1:10 000.
Conclusion
In twin pregnancies screening by cfDNA testing is feasible, but the failure rate is higher and detection rate may be lower than in singletons
Completeness of reporting of case reports in high-impact medical journals
Introduction: Case reports represent a relevant, timely and important study design in advancing medical scientific knowledge. They allow integration between clinical practice and clinical epidemiology. We aimed to assess the completeness of reporting (COR) of case reports published in high-impact journals. We assessed the COR of case reports using the CARE guidelines. Materials and methods: We selected three high-impact journals and one journal specialized in publishing case reports, in which we included all published case reports from July to December 2017. Median COR score was calculated per study, and CORs were compared between journals with and without endorsement of CARE guidelines. Results: One hundred and fourteen case reports were included. Overall median COR was 81%, IQR [63%-96%]. Sections with the highest COR (84%-100%) were patient information, clinical findings, therapeutic intervention, follow-up and outcomes, discussion and informed consent. Sections with the lowest COR were title, keywords, timeline and patient perspective (2%-34%). COR was higher in journals endorsing in comparison to those not endorsing CARE guidelines (77% vs 65%), respectively, median difference = −12% 95% CI [−16% to −7%]. Discussion: Overall completeness of case reports in included journals is high especially for CARE endorsing and dedicated journals but reporting of some items could be improved. Ongoing and future evaluations of endorsement status of reporting guidelines in medical journals should be assessed to improve completeness and reduce waste of clinical research, including case reports
Ensayos normativos para la caracterización de patologías en pizarras para cubiertas
The pathologies formed in slate roofs are mainly due to the presence of potentially unstable minerals (iron sulfides, carbonates and organic matter). These minerals may become altered by the effect of environmental agents, once the slate roof is finished. The pathologies are mainly associated with oxidation and gypsification processes of the cited mineral phases. In this work, the potential pathologies of several Spanish roofing slates are identified, using the tests defined in the European Norms EN 12326:2005, 14147:2004 and 11597:2007.Las patologías que se originan en pizarra para cubiertas son debidas fundamentalmente a la presencia de materiales alterables (sulfuros de hierro, carbonatos y materia orgánica). Estos minerales pueden llegar a alterarse por efecto de los agentes medioambientales, una vez que la pizarra es puesta en obra. Las patologías están principalmente asociadas a procesos de oxidación y yesificación de las citadas fases minerales. En este trabajo se determinan las patologías potenciales de varias pizarras para cubiertas españolas, utilizando los ensayos definidos en las normas UNE-EN 12326:2005, 14147:2004 y 11597:2007
Results from a Prototype Proton-CT Head Scanner
We are exploring low-dose proton radiography and computed tomography (pCT) as
techniques to improve the accuracy of proton treatment planning and to provide
artifact-free images for verification and adaptive therapy at the time of
treatment. Here we report on comprehensive beam test results with our prototype
pCT head scanner. The detector system and data acquisition attain a sustained
rate of more than a million protons individually measured per second, allowing
a full CT scan to be completed in six minutes or less of beam time. In order to
assess the performance of the scanner for proton radiography as well as
computed tomography, we have performed numerous scans of phantoms at the
Northwestern Medicine Chicago Proton Center including a custom phantom designed
to assess the spatial resolution, a phantom to assess the measurement of
relative stopping power, and a dosimetry phantom. Some images, performance, and
dosimetry results from those phantom scans are presented together with a
description of the instrument, the data acquisition system, and the calibration
methods.Comment: Conference on the Application of Accelerators in Research and
Industry, CAARI 2016, 30 October to 4 November 2016, Ft. Worth, TX, US
The S-Wave Pion-Nucleon Scattering Lengths from Pionic Atoms using Effective Field Theory
The pion-deuteron scattering length is computed to next-to-next-to-leading
order in baryon chiral perturbation theory. A modified power-counting is then
formulated which properly accounts for infrared enhancements engendered by the
large size of the deuteron, as compared to the pion Compton wavelength. We use
the precise experimental value of the real part of the pion-deuteron scattering
length determined from the decay of pionic deuterium, together with constraints
on pion-nucleon scattering lengths from the decay of pionic hydrogen, to
extract the isovector and isoscalar S-wave pion-nucleon scattering lengths, a^-
and a^+, respectively. We find a^-=(0.0918 \pm 0.0013) M_\pi^{-1} and
a^+=(-0.0034 \pm 0.0007) M_\pi^{-1}.Comment: 19 pages LaTeX, 7 eps fig
Evaluación del target strength de juveniles de atún rojo (Thunnus thynnus) en jaulas marinas
En los últimos años, el Instituto Español de Oceanografía (IEO) ha maximizado sus esfuerzos en desarrollar mecanismos para la cría en cautividad del atún rojo (Thunnus thynnus), cuyo ciclo completo está a punto de cerrarse. Este trabajo presenta los resultados obtenidos tras realizar mediciones acústicas con una ecosonda científica y un transductor split-beam en jaulas marinas donde los atunes, nacidos en cautividad, se separan en tres tamaños. La combinación de los datos acústicos y de los muestreos biométricos (obtenidos ópticamente) permite establecer una relación entre la longitud de los peces y el valor del target stregth (TS) devuelto por dichos peces.In recent years, the Spanish Institute of Oceanography (IEO) has maximized its efforts on developing mechanisms for the breeding of bluefin tuna (Thunnus thynnus), whose complete cycle is near to be closed. In this paper, acoustic measurements performed on young tuna cages (with scientific echosounder and split-beam transducer) are presented. Tuna housed in the cages were born in captivity and they are divided in three cages according to their size. The combination of the acoustic and biometric data (obtained with stereoscopic system) allow to establish a relationship between representative tuna length in each cage and the target strength (TS)
A renormalisation group approach to two-body scattering in the presence of long-range forces
We apply renormalisation-group methods to two-body scattering by a
combination of known long-range and unknown short-range potentials. We impose a
cut-off in the basis of distorted waves of the long-range potential and
identify possible fixed points of the short-range potential as this cut-off is
lowered to zero. The expansions around these fixed points define the power
countings for the corresponding effective field theories. Expansions around
nontrivial fixed points are shown to correspond to distorted-wave versions of
the effective-range expansion. These methods are applied to scattering in the
presence of Coulomb, Yukawa and repulsive inverse-square potentials.Comment: 22 pages (RevTeX), 4 figure
Wet in situ combustion: alternative for enhanced oil recovery in colombia
During the application of the enhanced oil recovery technique called in situ combustion, a great amount of the heat generated during combustion is stored in the burned sand behind the combustion front and is not used for oil displacement. The air heat capacity is low and the injected air can’t transfer heat from the sand matrix as rapidly as is generated. Water, on the other hand, can absorb and transport heat much more efficiently than air. If air is injected with water, the heat stored sand can be recovered and transported forward.
For the present research it was developed the numerical simulation model of the wet combustion tube test made to Colombian crude by the STARS simulator of the CMG company. For the development of the model, it was proposed a kinetic model that describes the oxidative behavior of the studied crude.Subsequently, it was made the history matching of the simulation model and were compared the numerical results with the results of the physical model. Finalized the simulation model, it was evaluated the effect of water on the performance parameters of the tube test model of wet combustion, for which it was made a sensitivity analysis to the water injection rate and it was analyzed its impact on each performance parameter.
Keywords: enhanced oil recovery, in situ combustion, numerical simulation model, combustion tube test,performance parameters.Durante la aplicación de la técnica de recobro mejorado del petróleo denominada combustión in situ, gran parte del calor generado durante la combustión se almacena en la arena calcinada detrás del frente de combustión y no se utiliza para el desplazamiento del aceite. La capacidad calorífica del aire seco es baja y el aire inyectado no puede transferir calor desde la matriz de la arena tan rápidamente como se genera. El agua por otra parte puede absorber y transportar el calor mucho más ficientemente que el aire. Si el aire se inyecta junto con el agua (combustión húmeda), el calor almacenado puede ser recuperado y transportado hacia adelante.
Para el presente estudio se desarrolló el modelo base de simulación numérica de la prueba de tubo de combustión húmeda realizada a un crudo colombiano, el simulador STARS de la compañía CMG. Para el desarrollo del mismo, se planteó un modelo cinético que describe el comportamiento oxidativo del crudo de estudio. Posteriormente, se realizó el ajuste histórico del modelo de simulación y se compararon los resultados numéricos con los resultados del modelo físico. Finalizado el modelo de simulación, se procedió a evaluar el efecto del agua sobre los parámetros de desempeño del modelo de la prueba de tubo de combustión húmeda, para lo cual se realizó un análisis de sensibilidad a la tasa de inyección de agua y se analizó su impacto sobre cada uno de los parámetros de desempeño
Interaction of HLA Class II rs9272219 and TMPO rs17028450 (Arg690Cys) Variants Affects Neuromyelitis Optica Spectrum Disorder Susceptibility in an Admixed Mexican Population
Neuromyelitis Optica Spectrum Disorder (NMOSD) is a demyelinating autoimmune disease of the central nervous system, more prevalent in individuals of non-European ancestry. Few studies have analyzed genetic risk factors in NMOSD, and HLA class II gene variation has been associated NMOSD risk in various populations including Mexicans. Thymopoietin (TMPO) has not been tested as a candidate gene for NMOSD or other autoimmune disease, however, experimental evidence suggests this gene may be involved in negative selection of autoreactive T cells and autoimmunity. We thus investigated whether the missense TMPO variant rs17028450 (Arg630Cys, frequent in Latin America) is associated with NMOSD, and whether this variant shows an interaction with HLA-class II rs9272219, previously associated with NMOSD risk. A total of 119 Mexican NMOSD patients, 1208 controls and 357 Native Mexican individuals were included. The HLA rs9272219 "T" risk allele frequency ranged from 21 to 68%, while the rs17028450 "T" minor allele frequency was as high as 18% in Native Mexican groups. Both rs9272219 and rs17028450 were significantly associated with NMOSD risk under additive models (OR = 2.48; p = 8 × 10(-10) and OR = 1.59; p = 0.0075, respectively), and a significant interaction between both variants was identified with logistic regression models (p = 0.048). Individuals bearing both risk alleles had an estimated 3.9-fold increased risk of NMOSD. To our knowledge, this is the first study reporting an association of TMPO gene variation with an autoimmune disorder and the interaction of specific susceptibility gene variants, that may contribute to the genetic architecture of NMOSD in admixed Latin American populations
Spallation Residues in the Reaction 56Fe + p at 0.3, 0.5, 0.75, 1.0 and 1.5 A GeV
The spallation residues produced in the bombardment of 56}Fe at 1.5, 1.0,
0.75, 0.5 and 0.3 A GeV on a liquid-hydrogen target have been measured using
the reverse kinematics technique and the Fragment Separator at GSI (Darmstadt).
This technique has permitted the full identification in charge and mass of all
isotopes produced with cross-sections larger than 10^{-2} mb down to Z=8. Their
individual production cross-sections and recoil velocities at the five energies
are presented. Production cross-sections are compared to previously existing
data and to empirical parametric formulas, often used in cosmic-ray
astrophysics. The experimental data are also extensively compared to different
combinations of intra-nuclear cascade and de-excitation models. It is shown
that the yields of the lightest isotopes cannot be accounted for by standard
evaporation models. The GEMINI model, which includes an asymmetric fission
decay mode, gives an overall good agreement with the data. These experimental
data can be directly used for the estimation of composition modifications and
damages in materials containing iron in spallation sources. They are also
useful for improving high precision cosmic-ray measurements.Comment: Submited to Phys. Rev. C (10/2006
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