388 research outputs found
Influence of a commercial antithrombotic filter on the caval blood flow during neutra and valsalva maneuver
Anticoagulants are the treatment of choice for pulmonary embolism. When these fail or are contraindicated, vena cava filters are effective devices for preventing clots from the legs from migrating to the lung. Many uncertainties exist when a filter is inserted, especially during physiological activity such as normal breathing and the Valsalva maneuver. These activities are often connected with filter migration and vena cava damage due to the various related vein geometrical configurations. In this work, we analyzed the response of the vena cava during normal breathing and Valsalva maneuver, for a healthy vena cava and after insertion of a commercial Günther-Tulip® filter. Validated computational fluid dynamics (CFD) and patient specific data are used for analyzing blood flow inside the vena cava during these maneuvers. While during normal breathing, the vena cava flow can be considered almost stationary with a very low pressure gradient, during Valsalva the extravascular pressure compresses the vena cava resulting in a drastic reduction of the vein section, a global flow decrease through the cava but increasing the velocity magnitude. This change in the section is altered by the presence of the filter which forces the section of the vena cava before the renal veins to keep open. The effect of the presence of the filter is investigated during these maneuvers showing changes in wall shear stress and velocity patterns
Polyaniline (PANI): an innovative support for sampling and removal of VOCs in air matrices
Polyaniline (PANI)-based materials for both removal and sampling of volatile organic compounds (VOCs) from air by rapid adsorption/desorption processes have been developed. The polymer was synthesized in form of emeraldine as both salt and base using different synthetic approaches, a traditional one and a "green" one. VOCs adsorption/desorption efficiency was evaluated for all the materials analyzing the desorbed VOCs fractions by GC/MS technique and obtaining results similar to the presently adopted method employing commercial activated carbon. Most important, in this work it has been demonstrated for the first time that the use of PANI-based sorbents allowed the substitution of the toxic CS2, recommended in official methods, with the less hazardous CH3OH as the VOCs extraction solvent. Moreover, a complete regeneration of the polymers could be realized by a few rapid washing steps. Finally, the best PANI-based material was subjected to recycling tests thereby showing a high adsorption/desorption efficiency retention up to four runs
Endoprótesis autoexpandibles en el tratamiento de la obstrucción de colon. Análisis dosimétrico
Objetivos: Realizar un análisis dosimétrico y comparar los resultados con las dosis de referencia de la colocación de endoprótesis autoexpandibles en el tratamiento de obstrucciones de colon y evaluar los efectos no estocásticos derivados de la radiación.
Material y métodos: Estudio descriptivo restrospectivo unicéntrico de 109 pro-cedimientos de colocación de endoprótesis autoexpandibles de colon. Incluye todas las obstrucciones de colon, la mayoría de causa maligna y alguna de causa benigna. Se realiza un análisis dosimétrico, comparándolo con las dosis de refe-rencia y un seguimiento para evaluar complicaciones.
Resultados: El tiempo medio de intervención fue de 55,84 minutos y el produc-to kermaa por área medio de 339600,64 mGy.cm². Se observó una correlación estadísticamente significativa entre dichas variables y el grado de complejidad de la intervención. Los valores obtenidos fueron superiores a los valores de refe-rencia. Solo en un 8,3 % de los pacientes que superaron el umbral de kerma se observaron complicaciones dérmicas.
Conclusiones: Esta intervención supone un tiempo de fluoroscopia y dosis de radiación considerable, observando una correlación estadísticamente significativa según el grado de dificultad de la intervención. Los radiólogos intervencionistas toman gran conciencia del problema, adoptando todas las medidas preventivas necesarias para lograr el éxito con la mínima dosis de radiación posible. En la mayoría de los casos, los beneficios clínicos y la mejora en la calidad de vida del paciente justifican el riesgo de la radiación. A pesar de las altas dosis recibidas, la incidencia de efectos no estocásticos es mínima
Effect of doped and undoped POMA on the morphology and miscibility of blends with Poly(vinylidene fluoride) (PVDF)
Symptom variability over the course of the day in patients with stable COPD in Brazil: a real-world observational study
Objetivo: Analisar os sintomas em diferentes momentos do dia em pacientes com DPOC. Métodos: Estudo observacional multicêntrico de corte transversal em oito centros brasileiros. Foram avaliados os sintomas matinais, diurnos e noturnos em pacientes com DPOC estável. Resultados: Foram incluídos 593 pacientes em tratamento regular, sendo 309 (52,1%) do sexo masculino e 92 (15,5%) fumantes ativos. A média de idade foi de 67,7 anos, e a média de VEF1 foi de 49,4% do valor previsto. Os pacientes com sintomas mais graves (n = 183; 30,8%), em comparação com aqueles com sintomas leves e moderados, apresentaram pior nível de atividade física (p = 0,002), maior limitação ao fluxo aéreo (p < 0,001), exacerbações ambulatoriais (p = 0,002) e hospitalares (p = 0,043) mais frequentemente e piores resultados em instrumentos específicos. Os sintomas matinais e noturnos mais frequentes foram dispneia (em 45,2% e 33,1%, respectivamente), tosse (em 37,5% e 33,3%, respectivamente) e chiado (em 24,4% e 27,0%, respectivamente). Houve forte correlação da intensidade dos sintomas diurnos com sintomas matinais (r = 0,65, p < 0,001), sintomas noturnos (r = 0,60, p < 0,001), bem como com o escore do COPD Assessment Test (r = 0,62; p < 0,001); porém, houve uma correlação fraca com VEF1 (r = −0,205; p < 0,001). Conclusões: A dispneia foi mais frequente no período matinal do que no período noturno. Ter sintomas matinais e/ou noturnos foi associado à pior gravidade dos sintomas diurnos. A intensidade dos sintomas foi fortemente associada a pior qualidade de vida e frequência de exacerbações, mas fracamente associada à limitação ao fluxo aéreo.463Objective: To analyze symptoms at different times of day in patients with COPD. Methods: This was a multicenter, cross-sectional observational study conducted at eight centers in Brazil. We evaluated morning, daytime, and nighttime symptoms in patients with stable COPD. Results: We included 593 patients under regular treatment, of whom 309 (52.1%) were male and 92 (15.5%) were active smokers. The mean age was 67.7 years, and the mean FEV1 was 49.4% of the predicted value. In comparison with the patients who had mild or moderate symptoms, the 183 (30.8%) with severe symptoms were less physically active (p = 0.002), had greater airflow limitation (p < 0.001), had more outpatient exacerbations (p = 0.002) and more inpatient exacerbations (p = 0.043), as well as scoring worse on specific instruments. The most common morning and nighttime symptoms were dyspnea (in 45.2% and 33.1%, respectively), cough (in 37.5% and 33.3%, respectively), and wheezing (in 24.4% and 27.0%, respectively). The intensity of daytime symptoms correlated strongly with that of morning symptoms (r = 0.65, p < 0.001) and that of nighttime symptoms (r = 0.60, p < 0.001), as well as with the COPD Assessment Test score (r = 0.62; p < 0.001), although it showed only a weak correlation with FEV1 (r = −0.205; p < 0.001). Conclusions: Dyspnea was more common in the morning than at night. Having morning or nighttime symptoms was associated with greater daytime symptom severity. Symptom intensity was strongly associated with poor quality of life and with the frequency of exacerbations, although it was weakly associated with airflow limitation
UV and EUV Instruments
We describe telescopes and instruments that were developed and used for
astronomical research in the ultraviolet (UV) and extreme ultraviolet (EUV)
regions of the electromagnetic spectrum. The wavelength ranges covered by these
bands are not uniquely defined. We use the following convention here: The EUV
and UV span the regions ~100-912 and 912-3000 Angstroem respectively. The
limitation between both ranges is a natural choice, because the hydrogen Lyman
absorption edge is located at 912 Angstroem. At smaller wavelengths,
astronomical sources are strongly absorbed by the interstellar medium. It also
marks a technical limit, because telescopes and instruments are of different
design. In the EUV range, the technology is strongly related to that utilized
in X-ray astronomy, while in the UV range the instruments in many cases have
their roots in optical astronomy. We will, therefore, describe the UV and EUV
instruments in appropriate conciseness and refer to the respective chapters of
this volume for more technical details.Comment: To appear in: Landolt-Boernstein, New Series VI/4A, Astronomy,
Astrophysics, and Cosmology; Instruments and Methods, ed. J.E. Truemper,
Springer-Verlag, Berlin, 201
Burden and challenges of heart failure in patients with chronic kidney disease. A call to action
Patients with the dual burden of chronic kidney disease (CKD) and chronic congestive heart
failure (HF) experience unacceptably high rates of symptom load, hospitalization, and mortality. Currently, concerted efforts to identify, prevent and treat HF in CKD patients are
lacking at the institutional level, with emphasis still being placed on individual specialty
views on this topic. The authors of this review paper endorse the need for a dedicated
cardiorenal interdisciplinary team that includes nephrologists and renal nurses and jointly manages appropriate clinical interventions across the inpatient and outpatient settings.
There is a critical need for guidelines and best clinical practice models from major cardiology
and nephrology professional societies, as well as for research funding in both specialties to
focus on the needs of future therapies for HF in CKD patients. The implementation of crossspecialty educational programs across all levels in cardiology and nephrology will help train
future specialists and nurses who have the ability to diagnose, treat, and prevent HF in CKD
patients in a precise, clinically effective, and cost-favorable manner.Los pacientes con enfermedad renal crónica (ERC) que desarrollan insuficiencia cardíaca (IC)
congestiva crónica presentan cifras inaceptablemente altas de síntomas, hospitalización y
mortalidad. Actualmente, se echan en falta iniciativas institucionales dirigidas a identificar,
prevenir y tratar la IC en los pacientes con ERC de manera multidisciplinar, prevaleciendo
las actuaciones de las especialidades individuales. Los autores de este artículo de revisión
respaldan la necesidad de crear equipos multidisciplinares cardiorrenales, en los que participen nefrólogos y enfermeras renales, que gestionen colaborativamente las intervenciones
clínicas apropiadas en los entornos de pacientes con ERC e IC hospitalizados y ambulatorios.
Es necesario y urgente que se elaboren guías y modelos de práctica clínica sobre la ERC con IC
por parte de las sociedades profesionales de cardiología y nefrología, así como financiación
para la investigación concertada entre ambas especialidades sobre la necesidad de futuros
tratamientos para la IC en pacientes con ERC. La implementación de programas educativos
cardiorrenales a todos los niveles en cardiología y nefrología ayudará a formar a los futuros
especialistas y enfermeras para que tengan la capacidad de diagnosticar, tratar y prevenir
la IC en pacientes con ERC de manera precisa, clínicamente efectiva y económicamente
favorabl
The composition of the protosolar disk and the formation conditions for comets
Conditions in the protosolar nebula have left their mark in the composition
of cometary volatiles, thought to be some of the most pristine material in the
solar system. Cometary compositions represent the end point of processing that
began in the parent molecular cloud core and continued through the collapse of
that core to form the protosun and the solar nebula, and finally during the
evolution of the solar nebula itself as the cometary bodies were accreting.
Disentangling the effects of the various epochs on the final composition of a
comet is complicated. But comets are not the only source of information about
the solar nebula. Protostellar disks around young stars similar to the protosun
provide a way of investigating the evolution of disks similar to the solar
nebula while they are in the process of evolving to form their own solar
systems. In this way we can learn about the physical and chemical conditions
under which comets formed, and about the types of dynamical processing that
shaped the solar system we see today.
This paper summarizes some recent contributions to our understanding of both
cometary volatiles and the composition, structure and evolution of protostellar
disks.Comment: To appear in Space Science Reviews. The final publication is
available at Springer via http://dx.doi.org/10.1007/s11214-015-0167-
Search for supersymmetry with a dominant R-parity violating LQDbar couplings in e+e- collisions at centre-of-mass energies of 130GeV to 172 GeV
A search for pair-production of supersymmetric particles under the assumption
that R-parity is violated via a dominant LQDbar coupling has been performed
using the data collected by ALEPH at centre-of-mass energies of 130-172 GeV.
The observed candidate events in the data are in agreement with the Standard
Model expectation. This result is translated into lower limits on the masses of
charginos, neutralinos, sleptons, sneutrinos and squarks. For instance, for
m_0=500 GeV/c^2 and tan(beta)=sqrt(2) charginos with masses smaller than 81
GeV/c^2 and neutralinos with masses smaller than 29 GeV/c^2 are excluded at the
95% confidence level for any generation structure of the LQDbar coupling.Comment: 32 pages, 30 figure
Search for the glueball candidates f0(1500) and fJ(1710) in gamma gamma collisions
Data taken with the ALEPH detector at LEP1 have been used to search for gamma
gamma production of the glueball candidates f0(1500) and fJ(1710) via their
decay to pi+pi-. No signal is observed and upper limits to the product of gamma
gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have
been measured to be Gamma_(gamma gamma -> f0(1500)). BR(f0(1500)->pi+pi-) <
0.31 keV and Gamma_(gamma gamma -> fJ(1710)). BR(fJ(1710)->pi+pi-) < 0.55 keV
at 95% confidence level.Comment: 10 pages, 3 figure
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