788 research outputs found
Predictive significance of the six-minute walk distance for long-term survival in chronic hypercapnic respiratory failure
Background: The 6-min walk distance ( 6-MWD) is a global marker of functional capacity and prognosis in chronic obstructive pulmonary disease ( COPD), but less explored in other chronic respiratory diseases. Objective: To study the role of 6-MWD in chronic hypercapnic respiratory failure ( CHRF). Methods: In 424 stable patients with CHRF and non-invasive ventilation ( NIV) comprising COPD ( n = 197), restrictive diseases ( RD; n = 112) and obesity-hypoventilation- syndrome ( OHS; n = 115), the prognostic value of 6-MWD for long- term survival was assessed in relation to that of body mass index (BMI), lung function, respiratory muscle function and laboratory parameters. Results: 6-MWD was reduced in patients with COPD ( median 280 m; quartiles 204/350 m) and RD ( 290 m; 204/362 m) compared to OHS ( 360 m; 275/440 m; p <0.001 each). Overall mortality during 24.9 (13.1/40.5) months was 22.9%. In the 424 patients with CHRF, 6-MWD independently predicted mortality in addition to BMI, leukocytes and forced expiratory volume in 1 s ( p <0.05 each). In COPD, 6-MWD was strongly associated with mortality using the median {[} p <0.001, hazard ratio ( HR) = 3.75, 95% confidence interval (CI): 2.24-6.38] or quartiles as cutoff levels. In contrast, 6-MWD was only significantly associated with impaired survival in RD patients when it was reduced to 204 m or less (1st quartile; p = 0.003, HR = 3.31, 95% CI: 1.73-14.10), while in OHS 6-MWD had not any prognostic value. Conclusions: In patients with CHRF and NIV, 6-MWD was predictive for long- term survival particularly in COPD. In RD only severely reduced 6-MWD predicted mortality, while in OHS 6-MWD was relatively high and had no prognostic value. These results support a disease-specific use of 6-MWD in the routine assessment of patients with CHRF. Copyright (C) 2007 S. Karger AG, Basel
Can Genetic Programming Do Manifold Learning Too?
Exploratory data analysis is a fundamental aspect of knowledge discovery that
aims to find the main characteristics of a dataset. Dimensionality reduction,
such as manifold learning, is often used to reduce the number of features in a
dataset to a manageable level for human interpretation. Despite this, most
manifold learning techniques do not explain anything about the original
features nor the true characteristics of a dataset. In this paper, we propose a
genetic programming approach to manifold learning called GP-MaL which evolves
functional mappings from a high-dimensional space to a lower dimensional space
through the use of interpretable trees. We show that GP-MaL is competitive with
existing manifold learning algorithms, while producing models that can be
interpreted and re-used on unseen data. A number of promising future directions
of research are found in the process.Comment: 16 pages, accepted in EuroGP '1
Enhancement of PLA-PVA surface adhesion in bilayer assemblies by PLA aminolisation
Data Availability: The raw/processed data required to reproduce these
findings cannot be shared at this time due to legal or ethical reasons.Poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVA) present complementary barrier properties, and their combination in multilayer assemblies (laminates) could provide materials with more effective barrier capacity for food packaging purposes. However, their low chemical affinity compromises adequate polymer adhesion. Surface free energy modification of thermo-processed PLA films through treatment with 1,6-hexanediamine was used to enhance adhesion with polar PVA aqueous solutions. Treatments of 1 and 3 min increased the polar component of the solid surface tension, while treatments above 10 min provoked a corrosive effect in the films structure. Extensibility analyses of PVA solutions loaded with carvacrol (15 wt.%) and different Tween 85 ratios on PLA-activated surfaces allowed the selection of the 1-min aminolysed surface for obtaining PLA-PVA bilayers, by casting PVA solutions on the PLA films. This study revealed that despite aminolisation enhancing the PLA surface affinity for aqueous PVA solutions, casting-obtained bilayers presented limited oxygen barrier effectiveness due to heterogeneous thickness of PVA layer in the laminates.The authors acknowledge the financial support provided by the Ministerio de Economia y Competitividad (MINECO) of Spain (project AGL2016-76699-R). The author A. Tampau thanks MINECO for the pre-doctoral research grant #BES-2014-068100.info:eu-repo/semantics/publishedVersio
Environmental variables, habitat discontinuity and life history shaping the genetic structure of Pomatoschistus marmoratus
Coastal lagoons are semi-isolated ecosystems
exposed to wide fluctuations of environmental conditions
and showing habitat fragmentation. These features may
play an important role in separating species into different
populations, even at small spatial scales. In this study, we
evaluate the concordance between mitochondrial (previous
published data) and nuclear data analyzing the genetic
variability of Pomatoschistus marmoratus in five localities,
inside and outside the Mar Menor coastal lagoon (SE
Spain) using eight microsatellites. High genetic diversity
and similar levels of allele richness were observed across
all loci and localities, although significant genic and
genotypic differentiation was found between populations
inside and outside the lagoon. In contrast to the FST values
obtained from previous mitochondrial DNA analyses
(control region), the microsatellite data exhibited significant
differentiation among samples inside the Mar Menor
and between lagoonal and marine samples. This pattern
was corroborated using Cavalli-Sforza genetic distances.
The habitat fragmentation inside the coastal lagoon and
among lagoon and marine localities could be acting as a
barrier to gene flow and contributing to the observed
genetic structure. Our results from generalized additive
models point a significant link between extreme lagoonal
environmental conditions (mainly maximum salinity) and
P. marmoratus genetic composition. Thereby, these environmental
features could be also acting on genetic structure
of coastal lagoon populations of P. marmoratus favoring
their genetic divergence. The mating strategy of P. marmoratus
could be also influencing our results obtained from
mitochondrial and nuclear DNA. Therefore, a special
consideration must be done in the selection of the DNA
markers depending on the reproductive strategy of the
species
A New Minimal-Stress Freely-Moving Rat Model for Preclinical Studies on Intranasal Administration of CNS Drugs
Purpose. To develop a new minimal-stress model for intranasal administration in freely moving rats and to evaluate in this model the brain distribution of acetaminophen following intranasal versus intravenous administration. Methods. Male Wistar rats received one intranasal cannula, an intra-cerebral microdialysis probe, and two blood cannulas for drug administration and serial blood sampling respectively. To evaluate this novel model, the following experiments were conducted. 1) Evans Blue was administered to verify the selectivity of intranasal exposure. 2) During a 1 min infusion 10, 20, or 40 μl saline was administered intranasally or 250 µl intravenously. Corticosterone plasma concentrations over time were compared as biomarkers for stress. 3) 200 µg of the model drug acetaminophen was given in identical setup and plasma, and brain pharmacokinetics were determined. Results. In 96 % of the rats, only the targeted nasal cavity was deeply colored. Corticosterone plasma concentrations were not influenced, neither by route nor volume of administration. Pharmacokinetics of acetaminophen were identical after intravenous and intranasal administration, although the Cmax in microdialysates was reached a little earlier following intravenous administration. Conclusion. A new minimal-stress model for intranasal administration in freely moving rats has been successfully developed and allows direct comparison with intravenous administration. KEY WORDS: acetaminophen; brain; intranasal infusion; microdialysis; pharmacokinetics
Infertility treatment outcome in sub groups of obese population
<p>Abstract</p> <p>Background</p> <p>Obesity is a common disorder with a negative impact on IVF treatment outcome. It is not clear whether morbidly obese women (BMI >= 35 kg/m2) respond to treatment differently as compared to obese women (BMI = 30–34.9 kg/m2) in IVF. Our aim was to compare the outcome of IVF or ICSI treatments in obese patients to that in morbidly obese patients.</p> <p>Methods</p> <p>This retrospective cohort study was conducted in a tertiary care centre. Patients inclusion criteria were as follows; BMI ≥ 30, age 20–40 years old, first cycle IVF/ICSI treatment with primary infertility and long follicular pituitary down regulation protocol.</p> <p>Results</p> <p>A total of 406 obese patients (group A) and 141 morbidly obese patients (group B) satisfied the inclusion criteria. Average BMI was 32.1 ± 1.38 kg/m2 for group A versus 37.7 ± 2.99 kg/m<sup>2 </sup>for group B. Patient age, cause of infertility, duration of stimulation, fertilization rate, and number of transferred embryos were similar in both groups. Compared to group A, group B had fewer medium size and mature follicles (14 vs. 16), fewer oocytes collected (7 vs. 9) and required higher doses of HMG (46.2 vs. 38.5 amps). There was also a higher cancellation rate in group B (28.3% vs. 19%) and lower clinical pregnancy rate per started cycle (19.9% vs. 28.6%).</p> <p>Conclusion</p> <p>In a homogenous infertile and obese patient population stratified according to their BMI, morbid obesity is associated with unfavorable IVF/ICSI cycle outcome as evidenced by lower pregnancy rates. It is recommended that morbidly obese patients undergo appropriate counseling before the initiation of this expensive and invasive therapy.</p
Physical and Antimicrobial Properties of Compression-Molded Cassava Starch-Chitosan Films for Meat Preservation
[EN] Cassava starch-chitosan films were obtained by melt bending and compression molding, using glycerol and polyethylene glycol as plasticizers. Both the starch/chitosan and the polymer/plasticizer ratios were varied in order to analyze their effect on the physical properties of the films. Additionally, the antimicrobial activity of 70:30 polymer:plasticizer films was tested in cold-stored pork meat slices as affected by chitosan content. All film components were thermally stable up to 200 A degrees C, which guaranteed their thermostability during film processing. Starch and chitosan had limited miscibility by melt blending, which resulted in heterogeneous film microstructure. Polyethylene glycol partially crystallized in the films, to a greater extent as the chitosan ratio increased, which limited its plasticizing effect. The films with the highest plasticizer ratio were more permeable to water vapor, less rigid, and less resistant to break. The variation in the chitosan content did not have a significant effect on water vapor permeability. As the chitosan proportion increased, the films became less stretchable, more rigid, and more resistant to break, with a more saturated yellowish color. The incorporation of the highest amount of chitosan in the films led to the reduction in coliforms and total aerobic counts of cold-stored pork meat slices, thus extending their shelf-life.The authors acknowledge the financial support provided by the Spanish Ministerio de Economia y Competividad (Projects AGL2013-42989-R and AGL2016-76699-R). Author Cristina Valencia-Sullca thanks the Peruvian Grant National Program (PRONABEC Grant).Valencia-Sullca, CE.; Atarés Huerta, LM.; Vargas, M.; Chiralt, A. (2018). Physical and Antimicrobial Properties of Compression-Molded Cassava Starch-Chitosan Films for Meat Preservation. Food and Bioprocess Technology. 11(7):1339-1349. https://doi.org/10.1007/s11947-018-2094-5S13391349117Alves, V. 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X-ray emission from the Sombrero galaxy: discrete sources
We present a study of discrete X-ray sources in and around the
bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival
Chandra observations with a total exposure of ~200 ks. With a detection limit
of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30
kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler
et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS
observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray
binaries (LMXBs). We quantify the differential luminosity functions (LFs) for
both the detected GC and field LMXBs, whose power-low indices (~1.1 for the
GC-LF and ~1.6 for field-LF) are consistent with previous studies for
elliptical galaxies. With precise sky positions of the GCs without a detected
X-ray source, we further quantify, through a fluctuation analysis, the GC LF at
fainter luminosities down to 1E35 erg/s. The derived index rules out a
faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent
findings in several elliptical galaxies and the bulge of M31. On the other
hand, the 2-6 keV unresolved emission places a tight constraint on the field
LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101
sources in the halo of Sombrero. The presence of these sources cannot be
interpreted as galactic LMXBs whose spatial distribution empirically follows
the starlight. Their number is also higher than the expected number of cosmic
AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray
surveys. We suggest that either the cosmic X-ray background is unusually high
in the direction of Sombrero, or a distinct population of X-ray sources is
present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
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