61 research outputs found
Volatile compounds of Morinda royoc L. fruit at two ripening stages
Morinda royoc L. (Rubiaceae), commonly known in Cuba as garañón, piñipiñi or piña ratón arbusto, is a plant typically found in coastal hammocks with medicinal properties. Application of headspace-solid phase microextraction combined with gas chromatography-mass spectrometry was used to analyze, for the first time, the volatile compounds of Morinda royoc L. fruits at to ripening stages. A fiber of polydimethylsiloxane-divinylbenzene (PDMS/DVB) was used for the extraction. The analyses led to the identification of 137 compounds, including 42 esters, 22 acids, 17 alcohols, 14 ketones, 14 terpenes, 9 aldehydes, 9 sulfur-compounds, 4 lactones, 3 phenols and derivatives, 3 paraffins and a nitrogen-compound. Qualitative and quantitatively, acids were a major chemical class of compounds in both maturity stages, mainly in the ripe stage. Although some compounds remain without changes in both ripening stages, the composition of certain volatile compounds clearly differs in both stages. The over-ripe fruit showed significantly higher amounts of 3-methyl-3-butenyl butanoate, 3-methyl-3-butenyl hexanoate and 3-methyl-3-butenyl octanoate, while 3-methyl-3-butenyl acetate, benzyl acetate and benzyl butanoate significantly decreased. The content of butanoic acid and 2-methylbutanoic acid increased from mature to over-ripe stage, while the major part of the other acids decreased during maturation
Comparison of the Analytical and Clinical Performance of Five Tests for the Detection of Human Papillomavirus Genital Infection
HPV-based screening provides greater protection against cervical
cancer (CC) than cytology-based strategies. Currently, several
molecular diagnostic assays for the detection of human
papillomavirus (HPV) are available. In this study, we analyzed 5
different HPV testing and genotyping techniques (Hybrid Capture
2 [HC2; Qiagen, Hilden, Germany], AnyplexTMII HPV28 [Anyplex;
Seegene, Seoul, Korea], Linear Array [Roche, Branchburg, NJ,
USA], GP5+/6+ PCR-EIA-RH [Labo Bio-medical Products, Rijswijk,
The Netherlands] and CLART2 [Genomica, Madrid, Spain]) in 295
women referred to the hospital Colposcopy Clinic from 2007 to
2008 due to positive HPV test results or an abnormal Pap test.
DNA extraction for HPV genotyping was performed in cervical
sample specimens after Pap test and HPV detection by HC2. The
inclusion criteria were: (1) adequate cervical sampling with
sufficient material for the Pap test and HPV detection and
genotyping, and (2) colposcopically-directed biopsy and/or
endocervical curettage. HC2 showed the highest sensitivity for
high-grade squamous intraepithelial lesion and CC (HSIL+)
detection (96.1%), but all the HPV genotyping tests showed a
higher specificity. (Anyplex 86.8%; Linear Array 86.0%; GP5+/6+
78.8%; CLART2 76.5%). The agreement between HC2 results and the
other techniques was similar: 82.4%, kappa=0.650 for Anyplex;
83.4%, kappa=0.670 for Linear Array, 79.93%, kappa=0.609 for
GP5+/6+ and 82.4%, kappa=0.654 for CLART2. HPV 16 and/or 18
infection was a risk factor for underlying HSIL+ in the
univariate analysis. Anyplex showed the highest risk of
underlying HSIL+ after positive HPV 16 and/or 18 tests (OR 31.1;
95% IC 12.1-80.0)
Classifying Parkinson’s Disease Patients With Syntactic and Socio-emotional Verbal Measures
Frontostriatal disorders, such as Parkinson’s disease (PD), are characterized by progressive disruption of cortico-subcortical dopaminergic loops involved in diverse higher-order domains, including language. Indeed, syntactic and emotional language tasks have emerged as potential biomarkers of frontostriatal disturbances. However, relevant studies and models have typically considered these linguistic dimensions in isolation, overlooking the potential advantages of targeting multidimensional markers. Here, we examined whether patient classification can be improved through the joint assessment of both dimensions using sentential stimuli. We evaluated 31 early PD patients and 24 healthy controls via two syntactic measures (functional-role assignment, parsing of long-distance dependencies) and a verbal task tapping social emotions (envy, Schadenfreude) and compared their classification accuracy when analyzed in isolation and in combination. Complementarily, we replicated our approach to discriminate between patients on and off medication. Results showed that specific measures of each dimension were selectively impaired in PD. In particular, joint analysis of outcomes in functional-role assignment and Schadenfreude improved the classification accuracy of patients and controls, irrespective of their overall cognitive and affective state. These results suggest that multidimensional linguistic assessments may better capture the complexity and multi-functional impact of frontostriatal disruptions, highlighting their potential contributions in the ongoing quest for sensitive markers of PD.Fil: Baez, Sandra. Universidad de los Andes; ColombiaFil: Herrera, Eduar. Universidad Icesi; ColombiaFil: Trujillo, Catalina. Universidad del Valle; ColombiaFil: Cardona, Juan F.. Universidad del Valle; ColombiaFil: Diazgranados, Jesús A.. Centro Médico de Atención Neurológica Neurólogos de Occidente; ColombiaFil: Pino, Mariana. Universidad Autónoma del Caribe; ColombiaFil: Santamaria Garcia, Hernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Hospital Universitario San Ignacio; Colombia. Pontificia Universidad Javeriana; ColombiaFil: Ibañez, Agustin Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Autónoma del Caribe; Colombia. Universidad de San Andrés; Argentina. Universidad Adolfo Ibañez; Chile. University of California; Estados UnidosFil: García, Adolfo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de San Andrés; Argentina. University of California; Estados Unidos. Universidad Catolica de Cuyo. Facultad de Educacion.; Argentin
Benchmarking of DFT methods using experimental free energies and volumes of activation for the cycloaddition of alkynes to cuboidal Mo3S4 clusters
Here, the kinetics of the concerted [3 + 2] cycloaddition reaction between the [Mo3(μ3‐S)(μ‐S)3Cl3(dmen)3]+ (dmen = N,N′‐dimethyl‐ethylenediamine) ([1]+) cluster and various alkynes to form dithiolene derivatives is thoroughly studied, with measurements at different temperatures and pressures allowing the determination of the free energies and volumes of activation. These parameters, together with the available single‐crystal X‐ray diffraction structures, are used to test a number of commonly used density functional theory (DFT) methods from Jacob's ladder, as well as the effects associated with the size of the basis sets, the way in which solvent effects are taken into account, or the inclusion of dispersion effects. Overall, a protocol that leads to average deviations between experimental and computed ΔV and ΔG values similar to the uncertainty of the experimental measurements is obtained
A Statistical Inference Method for Interpreting the CLASP Observations
On 3rd September 2015, the Chromospheric Lyman-Alpha SpectroPolarimeter
(CLASP) successfully measured the linear polarization produced by scattering
processes in the hydrogen Lyman- line of the solar disk radiation,
revealing conspicuous spatial variations in the and signals. Via
the Hanle effect the line-center and amplitudes encode information
on the magnetic field of the chromosphere-corona transition region (TR), but
they are also sensitive to the three-dimensional structure of this corrugated
interface region. With the help of a simple line formation model, here we
propose a statistical inference method for interpreting the Lyman-
line-center polarization observed by CLASP.Comment: Accepted for publication in The Astrophysical Journa
CLASP Constraints on the Magnetization and Geometrical Complexity of the Chromosphere-Corona Transition Region
The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a suborbital
rocket experiment that on 3rd September 2015 measured the linear polarization
produced by scattering processes in the hydrogen Ly- line of the solar
disk radiation, whose line-center photons stem from the chromosphere-corona
transition region (TR). These unprecedented spectropolarimetric observations
revealed an interesting surprise, namely that there is practically no
center-to-limb variation (CLV) in the line-center signals. Using an
analytical model, we first show that the geometrical complexity of the
corrugated surface that delineates the TR has a crucial impact on the CLV of
the and line-center signals. Secondly, we introduce a statistical
description of the solar atmosphere based on a three-dimensional (3D) model
derived from a state-of-the-art radiation magneto-hydrodynamic simulation. Each
realization of the statistical ensemble is a 3D model characterized by a given
degree of magnetization and corrugation of the TR, and for each such
realization we solve the full 3D radiative transfer problem taking into account
the impact of the CLASP instrument degradation on the calculated polarization
signals. Finally, we apply the statistical inference method presented in a
previous paper to show that the TR of the 3D model that produces the best
agreement with the CLASP observations has a relatively weak magnetic field and
a relatively high degree of corrugation. We emphasize that a suitable way to
validate or refute numerical models of the upper solar chromosphere is by
confronting calculations and observations of the scattering polarization in
ultraviolet lines sensitive to the Hanle effect.Comment: Accepted for publication in The Astrophysical Journal Letter
Evidence for the Operation of the Hanle and Magneto-Optical Effects in the Scattering Polarization Signals Observed by CLASP2 Across the Mg II h and k Lines
Radiative transfer investigations of the solar Mg II h and k resonance lines
around 280~nm showed that, while their circular polarization (Stokes V) signals
arise from the Zeeman effect, the linear polarization profiles (Stokes Q and U)
are dominated by the scattering of anisotropic radiation and the Hanle and
magneto-optical (MO) effects. Using the unprecedented observations of the Mg II
and Mn I resonance lines obtained by the Chromospheric LAyer
Spectro-Polarimeter (CLASP2), here we investigate how the linear polarization
signals at different wavelengths (i.e., at the center, and at the near and far
wings of the k line) vary with the longitudinal component of the magnetic field
() at their approximate height of formation. The is estimated
from the V signals in the aforementioned spectral lines. Particular attention
is given to the following quantities that are expected to be influenced by the
presence of magnetic fields through the Hanle and MO effects: the sign of the U
signals, the total linear polarization amplitude () and its direction
() with respect to a reference direction. We find that at the center and
near wings of the line, the behavior of these quantities is significantly
different in the observed quiet and plage regions, and that both and
seem to depend on . These observational results are indicative of
the operation of the Hanle effectComment: 26 pages, 18 figures, accepted for publication in the Astrophysical
Journa
Tomography of a solar plage with the Tenerife Inversion Code
We apply the Tenerife Inversion Code (TIC) to the plage spectropolarimetric
observations obtained by the Chromospheric LAyer SpectroPolarimeter (CLASP2).
These unprecedented data consist of full Stokes profiles in the spectral region
around the Mg II h and k lines for a single slit position, with around two
thirds of the 200 arcsec slit crossing a plage region and the rest crossing an
enhanced network. A former analysis of these data had allowed us to infer the
longitudinal component of the magnetic field by applying the weak field
approximation (WFA) to the circular polarization profiles, and to assign the
inferred magnetic fields to different layers of the solar atmosphere based on
the results of previous theoretical radiative transfer investigations. In this
work, we apply the recently developed TIC to the same data. We obtain the
stratified model atmosphere that fits the intensity and circular polarization
profiles at each position along the spectrograph slit and we compare our
results for the longitudinal component of the magnetic field with the
previously obtained WFA results, highlighting the generally good agreement in
spite of the fact that the WFA is known to produce an underestimation when
applied to the outer lobes of the Mg II h and k circular polarization profiles.
Finally, we use the inverted model atmospheres to give a rough estimation of
the energy that could be carried by Alfv\`en waves propagating along the
chromosphere in the plage and network regions, showing that it is sufficient to
compensate the estimated energy losses in the chromosphere of solar active
regions.Comment: Accepted for publication in The Astrophysical Journa
Cycloaddition of alkynes to diimino Mo3S4 cubane-type clusters: a combined experimental and theoretical approach
A heterocyclic ligand 4,40-di-tert-butyl-2,20-bipyridine (dbbpy) has been coordinated to the Mo3S4 cluster unit affording the complex [Mo3S4Cl3(dbbpy)3]+ ([1]+) in a one-step ligand-exchange protocol from [Mo3S4(tu)8(H2O)]Cl4 4H2O (tu = thiourea). The new cluster was isolated as [1]PF6 and [1]Cl salts in high yields and the crystal structure of the latter determined by X-ray analysis. The synthetic procedure was extended to tungsten to afford [W3S4Cl3(dbbpy)3]+ ([2]+). Kinetic and NMR studies show that [1]+ reacts with several alkynes to form dithiolene species via concerted [3+2] cycloaddition reactions whereas [2]+ remains inert under similar conditions. The different rates for the reactions of [1]+ are rationalised by computational (DFT) calculations, which show that the more electron-withdrawing the substituents of the alkyne the faster the reaction. The inertness of [2]+ is due to the endergonicity of its reactions, which feature DGr values systematically 5–7 kcal mol 1 more positive than for those of [1]+
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