5,956 research outputs found
Effect of metabolic and antioxidant supplementation on sperm parameters in oligo-astheno-teratozoospermia, with and without varicocele: a double-blind placebo-controlled study
Since sperm require high energy levels to perform their specialised function, it is vital that essential nutrients are available for spermatozoa when they develop, capacitate and acquire motility. However, they are vulnerable to a lack of energy and excess amounts of reactive oxygen species, which can impair sperm function, lead to immotility, acrosomal reaction impairment, DNA fragmentation and cell death. This monocentric, randomised, double-blind, placebo-controlled trial investigated the effect of 6 months of supplementation with l-carnitine, acetyl-l-carnitine and other micronutrients on sperm quality in 104 subjects with oligo- and/or astheno- and/or teratozoospermia with or without varicocele. In 94 patients who completed the study, sperm concentration was significantly increased in supplemented patients compared to the placebo (p =.0186). Total sperm count also increased significantly (p =.0117) in the supplemented group as compared to the placebo group. Both, progressive and total motility were higher in supplemented patients (p =.0088 and p =.0120, respectively). Although pregnancy rate was not an endpoint of the study, of the 12 pregnancies that occurred during the follow-up, 10 were reported in the supplementation group. In general, all these changes were more evident in varicocele patients. In conclusion, supplementation with metabolic and antioxidant compounds could be efficacious when included in strategies to improve fertility
Numerical and experimental assessment of the modal curvature method for damage detection in plate structures
This paper is concerned with the use of numerically obtained modal curvatures for damage detection in both isotropic and composite laminated plates. Numerical simulations are carried out by using COMSOL Multiphysics as FEM solver of the governing equations, in which a Mindlin-Reissner plate model is assumed and defects are introduced as localized smoothed variations of the baseline (healthy) configuration. Experiments are also performed on steel and aluminum plates using scanning laser vibrometry. This study confirms that the central difference method greatly amplifies the measurement errors and its application leads to ineffective predictions for damage detection, even after denoising. As a consequence, different numerical techniques should be explored to allow the use of numerically obtained modal curvatures for structural health monitoring. Herein, the Savitzky-Golay filter (or least-square smoothing filter) is considered for the numerical differentiation of noisy data
Numerical and experimental assessment of the modal curvature method for damage detection in plate structures
Use of modal curvatures obtained from modal displacement data for damage detection in isotropic and composite laminated plates is addressed through numerical examples and experimental tests. Numerical simulations are carried out employing COMSOL Multiphysics as finite element solver of the equations governing the Mindlin-Reissner plate model. Damages are introduced as localized non-smooth variations of the bending stiffness of the baseline (healthy) configuration. Experiments are also performed on steel and aluminum plates using scanning laser vibrometry. The obtained results confirm that use of the central difference method to compute modal curvatures greatly amplifies the measurement errors and its application leads to unreliable predictions for damage detection, even after denoising. Therefore, specialized ad hoc numerical techniques must be suitably implemented to enable structural health monitoring via modal curvature changes. In this study, the Savitzky-Golay filter (also referred to as least-square smoothing filter) is considered for the numerical differentiation of noisy data. Numerical and experimental results show that this filter is effective for the reliable computation of modal curvature changes in plate structures due to defects and/or damages
Common staining techniques for highlighting Acanthamoeba cysts
A 36-year-old woman returning from holiday in Portugal presented with bilateral ocular pain and acute visual loss. Eye examination revealed an inflammation in the anterior segment associated with corneal keratitis. During her trip, she wore contact lenses and rinsed the storage case using tap water. Corneal scrapings, contact lenses and cleaning solution from the case were inoculated onto agar plates supplemented with heat-inactivated bacteria. Bilateral Acanthamoeba keratitis was diagnosed, as microscopic examination of cultures from the last two samples revealed typical, spherical double-walled cystic structures (Fig. 1)
The Herschel exploitation of local galaxy Andromeda (HELGA) V: Strengthening the case for substantial interstellar grain growth
In this paper we consider the implications of the distributions of dust and
metals in the disc of M31. We derive mean radial dust distributions using a
dust map created from Herschel images of M31 sampling the entire far-infrared
(FIR) peak. Modified blackbodies are fit to approximately 4000 pixels with a
varying, as well as a fixed, dust emissivity index (beta). An overall metal
distribution is also derived using data collected from the literature. We use a
simple analytical model of the evolution of the dust in a galaxy with dust
contributed by stellar sources and interstellar grain growth, and fit this
model to the radial dust-to-metals distribution across the galaxy. Our analysis
shows that the dust-to-gas gradient in M31 is steeper than the metallicity
gradient, suggesting interstellar dust growth is (or has been) important in
M31. We argue that M31 helps build a case for cosmic dust in galaxies being the
result of substantial interstellar grain growth, while the net dust production
from stars may be limited. We note, however, that the efficiency of dust
production in stars, e.g., in supernovae (SNe) ejecta and/or stellar
atmospheres, and grain destruction in the interstellar medium (ISM) may be
degenerate in our simple model. We can conclude that interstellar grain growth
by accretion is likely at least as important as stellar dust production
channels in building the cosmic dust component in M31.Comment: 12 pages, 7 figures. Published in MNRAS 444, 797. This version is
updated to match the published versio
The degeneracy between star-formation parameters in dwarf galaxy simulations and the Mstar-Mhalo relation
We present results based on a set of N-Body/SPH simulations of isolated dwarf
galaxies. The simulations take into account star formation, stellar feedback,
radiative cooling and metal enrichment. The dark matter halo initially has a
cusped profile, but, at least in these simulations, starting from idealised,
spherically symmetric initial conditions, a natural conversion to a core is
observed due to gas dynamics and stellar feedback.
A degeneracy between the efficiency with which the interstellar medium
absorbs energy feedback from supernovae and stellar winds on the one hand, and
the density threshold for star formation on the other, is found. We performed a
parameter survey to determine, with the aid of the observed kinematic and
photometric scaling relations, which combinations of these two parameters
produce simulated galaxies that are in agreement with the observations.
With the implemented physics we are unable to reproduce the relation between
the stellar mass and the halo mass as determined by Guo et al. (2010), however
we do reproduce the slope of this relation.Comment: Accepted for publication in MNRAS | 12 pages, 8 figure
Insight into halloysite nanotubes-loaded gellan gum hydrogels for soft tissue engineering applications
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Impact of the different preparation methods to obtain human adipose-derived stromal vascular fraction cells (AD-SVFs) and human adipose-derived mesenchymal stem cells (AD-MSCs): Enzymatic digestion versus mechanical centrifugation
Autologous therapies using adipose-derived stromal vascular fraction (AD-SVFs) and adult adipose-derived mesenchymal stem cells (AD-MSCs) warrant careful preparation of the harvested adipose tissue. Currently, no standardized technique for this preparation exists. Processing quantitative standards (PQSs) define manufacturing quantitative variables (such as time, volume, and pressure). Processing qualitative standards (PQLSs) define the quality of the materials and methods in manufacturing. The purpose of the review was to use PQSs and PQLSs to report the in vivo and in vitro results obtained by different processing kits that use different procedures (enzymatic vs. non-enzymatic) to isolate human AD-SVFs/AD-MSCs. PQSs included the volume of fat tissue harvested and reagents used, the time/gravity of centrifugation, and the time, temperature, and tilt level/speed of incubation and/or centrifugation. PQLSs included the use of a collagenase, a processing time of 30 min, kit weight, transparency of the kit components, the maintenance of a closed sterile processing environment, and the use of a small centrifuge and incubating rocker. Using a kit with the PQSs and PQLSs described in this study enables the isolation of AD-MSCs that meet the consensus quality criteria. As the discovery of new critical quality attributes (CQAs) of AD-MSCs evolve with respect to purity and potency, adjustments to these benchmark PQSs and PQLs will hopefully isolate AD-MSCs of various CQAs with greater reproducibility, quality, and safety. Confirmatory studies will no doubt need to be completed
Prospective open-label study on the efficacy and tolerability of a combination of nutritional supplements in primary infertile patients with idiopathic astenoteratozoospermia
Aim of the study: To evaluate with an open-label study the efficacy and safety of a complex
of nutritional supplements with antioxidant activity (L-carnitine, acetyl-L-carnitine,
fructose, citric acid, selenium, coenzyme Q10, zinc, ascorbic acid, cyanocobalamin, folic
acid) in primary infertile patients with idiopathic astenoteratozoospermia.
Methods: The study was conducted in a population of 114 infertile men (96 completed the
study) diagnosed with idiopathic astenoteratozoospermia since at least 18 months.
Patients orally received a formulation (Proxeed - Sigma-Tau) containing L-carnitine 145 mg,
acetyl-L-carnitine 64 mg, fructose 250 mg, citric acid 50 mg, selenium 50 mcg, coenzyme Q10 20
mg, zinc 10 mg, ascorbic acid 90 mg, cyanocobalamin 1.5 mcg, folic acid 200 mcg in combination
once a day for 4 months.
Results: At the end of study, the mean sperm progressive motility showed a statistically significant
increase from 18.3 ± 3.8 to 42.1 ± 5.5. Sixteen patients achieved pregnancy during the study. No
significant improvement were observed for sperm density and rate of morphologically normal
forms. The treatment was well tolerated.
Conclusions: Carnitines in association with others functional substances can improve the most
important parameters of sperm quality
Universality of galactic surface densities within one dark halo scale-length
It was recently discovered that the mean dark matter surface density within
one dark halo scale length - the radius within which the volume density profile
of dark matter remains approximately flat - is constant across a wide range of
galaxies. This scaling relation holds for galaxies spanning a luminosity range
of 14 magnitudes and the whole Hubble sequence. Here we report that the
luminous matter surface density is also constant within one scale length of the
dark halo. This means that the gravitational acceleration generated by the
luminous component in galaxies is always the same at this radius. Although the
total luminous-to-dark matter ratio is not constant, within one halo scale
length it is constant. Our finding can be interpreted as a close correlation
between the enclosed surface densities of luminous and dark matter in galaxies.Comment: Accepted as a Letter to Natur
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