4,113 research outputs found
Synthesis, characterization, bioactivity and biocompatibility of nanostructured materials based on the wollastonite-poly(ethylmethacrylate-co-vinylpyrrolidone) system
Composite materials are very promising biomaterials
for hard tissue augmentation. The approach assayed
in this work involves the manufacturing of a composite
made of a bioactive ceramic, natural wollastonite (W) and a
nanostructured copolymer of ethylmethacrylate (EMA) and
vinylpyrrolidone (VP) to yield a bioresorbable and biocompatible
VP–EMA copolymer. A bulk polymerization was
induced thermally at 508C, using 1 wt % azobis(isobutyronitrile)
(AIBN) as free-radical initiator. Structural characterization,
compressive strength, flexural strength (FS), degradation,
bioactivity, and biocompatibility were evaluated in
specimens with a 60/40 VP/EMA ratio and ceramic content
in the range 0–60%. A good integration between phases
was achieved. Greater compression and FS, in comparison
with the pure copolymer specimens was obtained only
when the ceramic load got up to 60% of the total weight.
The soaking in NaCl solution resulted in the initial swelling
of the specimens tested. The maximum swelling was
reached after 2–3 h of immersion and it was significantly
greater for lower ceramic loads. This result makes the polymer
component the main responsible for the interactions
with the media. After soaking in SBF, microdomains segregation
can be observed in the polymer component that can
be related with a dramatic difference in the reactivity of
both monomers in free radical polymerization, whereas the
formation of an apatite-like layer on the W surfaces can be
observed. Biocompatibility in vitro studies showed the absence
of cytotoxicity of all formulations. The cells were able
to adhere on the polystyrene negative control and on specimens
containing 60 wt % wollastonite forming a monolayer
and showing a normal morphology. However, a low cellular
growth was observed. 2008 Wiley Periodicals, Inc.
J Biomed Mater Res 88A: 53–64, 2009Peer reviewe
Modelos de gestión en nutrición clínica. Puntos débiles y puntos fuertes
En el VIº Foro de Debate Abbott-SENPE se establece una discusión multidisciplinar y multiprofesional para buscar el o los modelos de gestión clínica que consideramos más adecuados para la Unidades de Nutrición
Clínica y Dietética (UNCyD) en España. Se valoran los puntos débiles y fuertes así como las oportunidades de los actuales sistemas y se concluye en la observación de una cierta disparidad vinculada no solo a las comunidades autónomas sino también a los diferentes tipos de hospital.
Se propone, desde SENPE, la creación de un grupo de trabajo
que ayude a la normalización de los modelos y a potenciar la cultura del Cuadro de Mandos Integral y de Gestión del Cambio.At the 6th Abbott-SENPE Debate Forum a multidisciplinary and multiprofessional discussion was established in order to seek for the model or the models of clinical management most appropriate for Clinical Nutrition and Dietetics Units (CNAD) in Spain. The weaknesses and strengths as well as opportunities for the current systems were assessed concluding that a certain degree of disparity was observed not only due to regional differences but also to different hospital types. It was proposed, from SENPE, the creation of a working group helping to standardize the models and promote the culture of Integral Control and Change Management
The upper Valanginian of the Oliva section (Prebetic Zone, Valencia): facies analysis, biostratigraphy, C-isotope stratigraphy and organic geochemistry
The Upper Valanginian stratigraphic section of the sierra de la Oliva (Prebetic,
Valencia province) records a significant sedimentary episode which has
been named as ”Weissert Event”.This event is characterized by a positive excursion
in the δ13C profile, which have been considered to be linked to a
global perturbation in the carbon cycle, with environmental consequences
that have been the object of debate, especially the degree of oxygenation of
the sea bottom waters.We studied the sedimentary evolution during the late
Valanginian in a shallow platform setting, beginning with the drowning of
the early Valanginian carbonate platform, followed by a succession of shallowing-
upwards sequences, which define a general deepening-upward evolution.
The δ13C profile records a positive excursion during the late Valanginian,
and the biomarker study has revealed the episodic development of
anoxia, coeval to the deposition of organic rich facies, occurred during the
episode of maximum deepening of the platform.This study has demonstrated
that the “Weissert Event” has been recorded in the Prebetic platform, and
that the environmental perturbations gave place to the occasional development
of anoxia in a context of high organic productivityLa sección estratigráfica del Valanginiense superior de la sierra de la
Oliva (Prebético, provincia de Valencia) registra un interesante episodio sedimentario
que ha sido denominado “Evento Weissert”. Este evento está
caracterizado por una excursión positiva en los valores del δ13C, que se considera
ligada a una perturbación global en el ciclo del carbono, cuyas consecuencias
ambientales son objeto de discusión, especialmente las condiciones
de oxigenación en los fondos marinos. El estudio presentado aquí
muestra la evolución sedimentaria del Valanginiense superior en un ámbito
de plataforma somera, que comienza con el drowning de la plataforma carbonatada
del Valanginiense inferior, y continúa con una sucesión de secuencias
de somerización, que en conjunto definen una evolución general de
profundización. El perfil de δ13C registra una excursión positiva durante el
Valanginiense superior, y el estudio de los biomarcadores ha puesto de manifiesto
el desarrollo puntual de anoxia, simultáneo al depósito de facies
ricas en materia orgánica, ocurrido en el momento de mayor profundización
de la plataforma. Este estudio demuestra que el denominado “EventoWeissert”
quedó reflejado en la plataforma Prebética, y que las perturbaciones
ambientales locales dieron lugar al desarrollo puntual de anoxia en un contexto
de elevada productividad orgánic
Low skeletal muscle mass assessed directly from the 3rd cervical vertebra can predict pharyngocutaneous fistula risk after total laryngectomy in the male population
Altres ajuts: Acord transformatiu CRUE-CSICAltres ajuts: Open Access Funding provided by Universitat Autonoma de Barcelona. European Regional Development Fund (A Way to Build Europe).Purpose: Skeletal muscle mass (SMM) loss and sarcopenia have been identified as risk factors for postoperative complications. The aim of this study was to investigate the relationship between pharyngocutaneous fistula (PCF) formation after total laryngectomy (TL) and SMM assessed from a computed tomography image of the 3rd cervical vertebra (C3). Methods: Retrospective study of 86 male patients who underwent TL between 2013 and 2019 in a single institution. We excluded women from the analysis due to our limited sample. SMM was determined from cross-sectional muscle area (CSMA) measurement at C3 using the ImageJ software. Results were compared with those for the skeletal muscle mass index (SMMI) calculated from the estimated measure at 3rd lumbar vertebra (L3). Results: PCF formation occurred in 21/86 patients. According to the CSMA at a C3 cut-off of 35.5cm2, of 18 patients (20.9%) with low SMM, 9 developed PCFs (50.0%). Among patients with normal SMM (n = 68, 79.1%), 12 developed PCFs (17.6%). The CSMA at C3 was the only variable significantly associated with PCF risk, which was 4.7 times greater in patients with low SMM (p = 0.007). Sarcopenia was more frequent in underweight patients (p = 0.0001), patients undergoing extended surgeries (p = 0.003), or presenting preoperative anaemia (p = 0.009) or hypoalbuminemia (p = 0.027). Conclusion: Measuring the CSMA at C3 obtained results equivalent to those obtained by calculating the SMMI at L3, suggesting that direct SMM assessment from C3 is a useful approach to evaluating PCF formation risk after TL
Central star formation and metallicity in CALIFA interacting galaxies
We use optical integral-field spectroscopic (IFS) data from 103 nearby
galaxies at different stages of the merging event, from close pairs to merger
remnants provided by the CALIFA survey, to study the impact of the interaction
in the specific star formation and oxygen abundance on different galactic
scales. To disentangle the effect of the interaction and merger from internal
processes, we compared our results with a control sample of 80 non-interacting
galaxies. We confirm the moderate enhancement (2-3 times) of specific star
formation for interacting galaxies in central regions as reported by previous
studies; however, the specific star formation is comparable when observed in
extended regions. We find that control and interacting star-forming galaxies
have similar oxygen abundances in their central regions, when normalized to
their stellar masses. Oxygen abundances of these interacting galaxies seem to
decrease compared to the control objects at the large aperture sizes measured
in effective radius. Although the enhancement in central star formation and
lower metallicities for interacting galaxies have been attributed to tidally
induced inflows, our results suggest that other processes such as stellar
feedback can contribute to the metal enrichment in interacting galaxies.Comment: 9 pages, 9 figures. Accepted for publication in Astronomy &
Astrophysic
The effects of spatial resolution on Integral Field Spectrograph surveys at different redshifts. The CALIFA perspective
Over the past decade, 3D optical spectroscopy has become the preferred tool
for understanding the properties of galaxies and is now increasingly used to
carry out galaxy surveys. Low redshift surveys include SAURON, DiskMass,
ATLAS3D, PINGS and VENGA. At redshifts above 0.7, surveys such as MASSIV, SINS,
GLACE, and IMAGES have targeted the most luminous galaxies to study mainly
their kinematic properties. The on-going CALIFA survey () is the
first of a series of upcoming Integral Field Spectroscopy (IFS) surveys with
large samples representative of the entire population of galaxies. Others
include SAMI and MaNGA at lower redshift and the upcoming KMOS surveys at
higher redshift. Given the importance of spatial scales in IFS surveys, the
study of the effects of spatial resolution on the recovered parameters becomes
important. We explore the capability of the CALIFA survey and a hypothetical
higher redshift survey to reproduce the properties of a sample of objects
observed with better spatial resolution at lower redshift. Using a sample of
PINGS galaxies, we simulate observations at different redshifts. We then study
the behaviour of different parameters as the spatial resolution degrades with
increasing redshift.Comment: 20 pages, 16 figures. Accepted for publication in A&
Evolution of the Fundamental Plane of 0.2<z<1.2 Early-type galaxies in the EGS
The Fundamental Plane relates the structural properties of early-type
galaxies such as its surface brightness and effective radius with its dynamics.
The study of its evolution has therefore important implications for models of
galaxy formation and evolution. This work aims to identify signs of evolution
of early-type galaxies through the study of parameter correlations using a
sample of 135 field galaxies extracted from the Extended Groth Strip in the
redshift range 0.2<z<1.2. Using DEEP2 data, we calculate the internal velocity
dispersions by extracting the stellar kinematics from absorption line spectra,
using a maximum penalized likelihood approach. Morphology was determined
through visual classification using the V+I images of ACS. The structural
parameters of these galaxies were obtained by fitting de Vaucouleurs stellar
profiles to the ACS I-band images, using the GALFIT code. S\'ersic and
bulge-to-disc decomposition models were also fitted to our sample of galaxies,
and we found a good agreement in the Fundamental Plane derived from the three
models. Assuming that effective radii and velocity dispersions do not evolve
with redshift, we have found a brightening of 0.68 mag in the B-band and 0.52
mag in the g-band at =0.7. However, the scatter in the FP is reduced by half
when we allow the FP slope to evolve, suggesting a different evolution of
early-type galaxies according to their intrinsic properties. The study of the
Kormendy relation shows the existence of a population of very compact (Re<2
Kpc) and bright galaxies (-21.5>Mg>-22.5), of which there are only a small
fraction (0.4%) at z=0. The evolution of these compact objects is mainly caused
by an increase in size that could be explained by the action of dry minor
mergers, and this population is responsible for the evolution detected in the
Fundamental Plane.Comment: Accepted for publication in A&A. 12 pages, 10 Figures, and 1 online
tabl
Advanced determination of piezoelectric properties of AlN thin films on silicon substrates
Piezoelectric deformations of thin, aluminum nitride (AlN) layers, on top of a silicon substrate, were studied by numerical calculations and interferometric measurements. Our calculation by finite element method demonstrates that substrate deformation under the top electrode may be comparable to the electric field induced deformation in the thin AlN layer, for a given applied voltage. Simulations also show the effect of a clamped or free substrate condition and the relative contributions of d33 and d31 piezoelectric constants. A Laser scanning vibrometry technique was used to measure deformations in the top surface with sub-picometer vertical resolution. By comparing calculations and experimental data, quantitative information about both d33 and d31 constants can be obtained
Effects of weight loss after bariatric surgery on pulmonary function tests and aobtructive sleep apnea in morbidly obese women
Introducción: la obesidad afecta a la función respiratoria
e incrementa el riesgo de síndrome de apneas-hipopneas
del sueño (SAHS).
Objetivo: evaluar el efecto de la cirugía bariátrica, en
mujeres con obesidad mórbida, sobre la función respiratoria
y sobre el índice de apneas-hipopneas (IAH) tras
dos años de seguimiento.
Métodos: se incluyeron 15 mujeres (índice de masa
corporal [IMC] medio 50,52 ± 12,71 kg.m-2, edad media
40,13 ± 10,06 años). Los enfermos fueron analizados en
dos fases: previo a la cirugía bariátrica y tras dos años
de la misma. En cada visita se valoraron las medidas
antropométricas y se realizaron pruebas de función respiratoria
consistentes en espirometría, pletismografía,
medida de la presión inspiratoria máxima y del índice
de tensión-tiempo de los músculos inspiratorios, así como
análisis de gases arteriales. Por último, también se efectuó
una poligrafía cardiorrespiratoria durante el sueño.
Resultados: tras la cirugía bariátrica el IMC disminuyó
en 44,07 kg.m-2 (IC 95% 38,32 – 49,81). De igual
forma, se observaron incrementos significativos en el
volumen espiratorio forzado al primer segundo (FEV1)
(p < 0,01), la capacidad vital forzada (FVC) (p < 0,01), el
volumen de reserva espiratorio (ERV) (p = 0,040), la capacidad
funcional residual (FRC) (p = 0,009) y la resistencia
de las vías aéreas (Raw) (p = 0,018). Por otra parte,
el IAH (p = 0,001) y el índice de desaturación de oxígeno
(p = 0,001) disminuyeron tras la cirugía. Se observó una
correlación significativa entre el grado de pérdida de
peso y el incremento del ERV (0,774, p = 0,024).
Conclusiones: tras dos años desde la cirugía bariátrica
se siguen observando mejorías significativas en la función
respiratoria y en la gravedad del SAHS. La mejoría
del ERV estaría en relación directa con los niveles de peso
perdidoIntroduction: obesity impacts on respiratory function
and also it acts as a risk factor for obstructive sleep apnea
(OSA).
Aims: to study the effects of bariatric surgery on pulmonary
function tests and on OSA in morbidly obese women
over 4 years.
Methods: fifteen morbidly obese women (mean
body mass index [BMI] 50.52 ± 12.71 kg.m-2, mean age
40.13 ± 10.06 years) underwent pulmonary function tests
(PFT) in two opportunities (before and after weight loss
surgery). PFT included spirometry, body plethysmography
and measure of maximal inspiratory mouth pressure
(PImax) and of tension-time index for inspiratory muscles.
Also, in both opportunities, resting arterial blood gas tensions
were evaluated and a full night sleep register was
performed.
Results: BMI significantly decreased after bariatric
surgery (-44.07 kg.m-2 [CI 95% -38.32 – -49.81]). Also,
there was a significantly increase in forced expiratory
volume in 1 second (FEV1) (p < 0.01), forced vital capacity
(FVC) (p < 0.01), expiratory reserve volume (ERV)
(p = 0.040), functional residual capacity (FRC) (p = 0.009)
and a decline in airways resistance (Raw) (p = 0.018).
Concerning sleep registers, apnea hypopnea index
(p = 0.001) and desaturation index (p = 0.001) were also
reduced after weight loss. Improve in ERV had a significant
correlation with weight loss (r = 0.774, p = 0.024).
Conclussions: pulmonary function tests and apnea
hypopnea index improve after bariatric surgery in mor-
bidly obese women. Improvement of ERV is well correlated
with weight los
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