61 research outputs found

    Volatile compounds of Morinda royoc L. fruit at two ripening stages

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    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

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    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

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    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

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    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

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    On 3rd September 2015, the Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) successfully measured the linear polarization produced by scattering processes in the hydrogen Lyman-α\alpha line of the solar disk radiation, revealing conspicuous spatial variations in the Q/IQ/I and U/IU/I signals. Via the Hanle effect the line-center Q/IQ/I and U/IU/I 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-α\alpha 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

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    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-α\alpha 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 Q/IQ/I 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 Q/IQ/I and U/IU/I 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

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    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 (BLB_{L}) at their approximate height of formation. The BLB_{L} 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 (LPLP) and its direction (χ\chi) with respect to a reference direction. We find that at the center and near wings of the kk line, the behavior of these quantities is significantly different in the observed quiet and plage regions, and that both LPLP and χ\chi seem to depend on BLB_{L}. 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

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    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

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    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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