858 research outputs found
Biodegradable Polyester Films from Renewable Aleuritic Acid: Surface Modifications Induced by Melt-polycondensation in Air.
Good water barrier properties and biocompatibility of long-chain biopolyesters like
cutin and suberin have inspired the design of synthetic mimetic materials. Most of these
biopolymers are made from esterified mid-chain functionalized ω-long chain hydroxyacids.
Aleuritic (9,10,16-trihydroxypalmitic) acid is such a polyhydroxylated fatty acid and
is also the major constituent of natural lac resin, a relatively abundant and renewable
resource. Insoluble and thermostable films have been prepared from aleuritic acid by meltcondensation
polymerization in air without catalysts, an easy and attractive procedure for
large scale production. Intended to be used as a protective coating, the barrier's performance
is expected to be conditioned by physical and chemical modifications induced by oxygen
on the air-exposed side. Hence, the chemical composition, texture, mechanical behavior,
hydrophobicity, chemical resistance and biodegradation of the film surface have been studied
by attenuated total reflection–Fourier transform infrared spectroscopy (ATR–FTIR), atomic
force microscopy (AFM), nanoindentation and water contact angle (WCA). It has been
demonstrated that the occurrence of side oxidation reactions conditions the surface physical
and chemical properties of these polyhydroxyester films. Additionally, the addition of palmitic
acid to reduce the presence of hydrophilic free hydroxyl groups was found to have a strong
influence on these parametersPeer reviewe
An alternative approach to the tomographic reconstruction of smooth refractive index distributions
Continuous, mathematically smooth Phase Objects with radial symmetry are reconstructed from cross sections of their refractive index distribution by a novel method, consisting of a linear combination of Gaussian basis functions, whose technical details are discussed. As an application example, this approach is used to get a fast and accurate estimation of the temperature distribution of an actual soldering tip
Identificación inicial de genes en Babesia bigemina mediante análisis de Etiquetas de Secuencia Expresadas en el estadio intraeritrocítico del parásito
In this study, Expressed Sequence Tags (EST) were obtained and analyzed from 2208 randomly selected clones containing plasmids with cDNA inserts derived from a Babesia bigemina library. The obtained sequences were extracted and subject to Blast homology search in the Genbank databases. Sequence homology analysis resulted in the identification of 470 clones (grouped in 267 distinct clusters) which contained EST with no significant sequence identity with Babesia sp genes or other Apicomplexan parasites. Presumably, these EST would correspond either to new, unreported B. bigemina transcribed genes present in the erythrocyte stages of the parasite, or to non-translated sequences of the putative genes. 21 clones were identified which contained EST corresponding to 6 genes coding for B. bigemina antigens already reported in the literature; 1285 clones (grouped in 159 clusters of distinct sequences) had significant sequence identity with genes coding for hypothetical proteins previously identified in the Babesia bovis genome. Moreover, 32 clones had EST corresponding to 16 different Theileria sp. genes; 51 clones (26 distinct sequences) showed EST with sequence similarity to genes of Plasmodium sp., 25 EST had low identity with 13 different Toxoplasma gondii genes; and 4 clones with EST for 4 different Cryptosporidium sp genes. The results obtained, in addition to EST analysis of a larger number of B. bigemina cDNA clones, will allow the characterization and, eventually, the manipulation of gene coding regions, essential for the establishment of improved control strategies for cattle babesiosis caused by B. bigemina.En este estudio se realizó el análisis de Etiquetas de Secuencias Expresadas (EST) obtenidas a partir de 2208 clonas de Escherichia coli, con plásmidos recombinantes conteniendo insertos de cDNA de Babesia bigemina. Las secuencias se analizaron mediante búsqueda de homología en las bases de datos de genes. El análisis de homología en secuencia permitió identificar 470 clonas (agrupadas en 267 clusters) conteniendo EST con similitud de secuencia estadísticamente no significativa con algún gen de Babesia spp o de otro organismo Apicomplexa, sugiriendo la presencia de genes nuevos de B. bigemina; Se identificaron 21 clonas con EST correspondientes a 6 secuencias de genes previamente reportados para B. bigemina; además de 1285 clonas (conformando 159 clusters de genes distintos) de identidad significativa con proteínas hipotéticas o correspondientes a genes ya reportados en el genoma secuenciado de Babesia bovis; 32 clonas con EST homólogas a 16 genes distintos de Theileria spp; 51 clonas (26 genes distintos) con similitud en secuencia a genes de Plasmodium spp; 25 clonas con EST de moderada similitud con 13 genes distintos genes de Toxoplasma gondii; y 4 clonas con EST de mayor identidad con 4 genes diferentes de Cryptosporidium spp. Los resultados obtenidos permiten elaborar una base de datos sobre EST del estadio intraeritrocítico de Babesia bigemina, información básica esencial para la caracterización molecular del parásito, que permite llevar a cabo la identificación y regulación de nuevas regiones génicas codificadoras y, eventualmente el establecimiento de nuevas estrategias de control de la babesiosis bovina causada por B. bigemina
An alternative method for phase-unwrapping of interferometric data
In this paper we present a novel algorithm for phase unwrapping where only a subset of data from the wrapped phase map is used to reconstruct the unwrapped phase map as a linear combination of radial basis functions (RBF’s). For noisy phase maps this algorithm gives better results than three reference algorithms based on radial basis functions, Zernike polynomials and path dependent phase unwrapping strategies
Effectiveness of a cardiovascular risk management program in reducing the probability of premature death due to cardiovascular events in the Colombian caribbean region
Effectiveness of a cardiovascular risk management program in reducing the probability of premature death due to cardiovascular events in the Colombian Caribbean regio
Effectiveness of a cardiovascular risk management program in the incidence of cardiovascular events in a low-income population from the caribbean region of Colombia
Methods
This was a retrospective cohort study. Patients with 20 to 76 years affiliated to insurer company and enrolled to the DTC program were considered as the study population. The data source was an administrative database of all 128,263 patients between Jan 2015 and Dec 2018. The main outcome was the reduction in the risk of a CVE (stroke, AMI or CHF) based in the time-person exposed to the intervention. Four different time thresholds were considered for stablishing exposure status: six months, one year, two years and four years. Propensity score-weighted Cox regression models were used to evaluate the association between exposure to the program and the incidence of CVE
Diagnostic Accuracy of Anthropometric Markers of Obesity for Prediabetes: A Systematic Review and Meta-Analysis
Introduction: Prediabetes is a significant public health concern due to its high risk of progressing to diabetes. Anthropometric measures of obesity, including body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) have been demonstrated as key risk factors in the development of prediabetes. However, there is a lack of clarity on the diagnostic accuracy and cut-off points of these measures.
Objective: To determine the diagnostic accuracy of these anthropometric measures for their most effective use in identifying prediabetes.
Methodology: A systematic review (SR) with metanalysis of observational studies was carried out. The search was conducted in four databases: Pubmed/Medline, SCOPUS, Web of Science, and EMBASE. For the meta-analysis, sensitivity and specificity, together with their 95% confidence intervals (CI 95%) were calculated.
Results: Among all the manuscripts chosen for review, we had four cross-sectional studies, and three were classified as cohort studies.
The forest plots showed the combined sensitivity and specificity for both cross-sectional and cohort studies. For cross-sectional studies, the values were as follows: BMI had a sensitivity of 0.63 and specificity of 0.56, WC had a sensitivity of 0.59 and specificity of 0.58, and WHtR had a sensitivity of 0.63 and specificity of 0.73. In the cohort studies, the combined sensitivity and specificity were: BMI at 0.70 and 0.45, WC at 0.68 and 0.56, and WHtR at 0.68 and 0.56, respectively. All values are provided with 95% confidence intervals.
Conclusions: This systematic review and meta-analysis evaluated the diagnostic accuracy of BMI, WC, and WHtR in identifying prediabetes. The results showed variations in sensitivity and specificity, with WHtR having the highest specificity in cross-sectional studies and BMI having improved sensitivity in cohort studies
The 2HWC HAWC Observatory Gamma Ray Catalog
We present the first catalog of TeV gamma-ray sources realized with the
recently completed High Altitude Water Cherenkov Observatory (HAWC). It is the
most sensitive wide field-of-view TeV telescope currently in operation, with a
1-year survey sensitivity of ~5-10% of the flux of the Crab Nebula. With an
instantaneous field of view >1.5 sr and >90% duty cycle, it continuously
surveys and monitors the sky for gamma ray energies between hundreds GeV and
tens of TeV.
HAWC is located in Mexico at a latitude of 19 degree North and was completed
in March 2015. Here, we present the 2HWC catalog, which is the result of the
first source search realized with the complete HAWC detector. Realized with 507
days of data and represents the most sensitive TeV survey to date for such a
large fraction of the sky. A total of 39 sources were detected, with an
expected contamination of 0.5 due to background fluctuation. Out of these
sources, 16 are more than one degree away from any previously reported TeV
source. The source list, including the position measurement, spectrum
measurement, and uncertainties, is reported. Seven of the detected sources may
be associated with pulsar wind nebulae, two with supernova remnants, two with
blazars, and the remaining 23 have no firm identification yet.Comment: Submitted 2017/02/09 to the Astrophysical Journa
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