Influence of plant resistance traits in selectiveness and species strength in a tropical plant-herbivore network.

PREMISE OF THE STUDY: Plant-herbivore networks are highly specialized in their interactions, yet they are highly variable with regard to the relative importance of specific host species for herbivores. How host species traits determine specialization and species strength in this antagonistic network is still an unanswered question that we addressed in this study. METHODS: We assessed plant cover and antiherbivore resistance traits to assess the extent to which they accounted for the variation in specialization and strength of interactions among species in a plant-herbivore network. We studied a tropical antagonistic network including a diverse herbivore-host plant assemblages in different habitat types and climatic seasons, including host plants with different life histories. KEY RESULTS: Particular combinations of leaf toughness, trichome density, and phenolic compounds influenced herbivore specialization and host species strength, but with a significant spatiotemporal variation among plant life histories. Conversely, plant-herbivore network parameters were not influenced by plant cover. CONCLUSIONS: Our study highlights the importance of species-specific resistance traits of plants to understand the ecological and evolutionary consequences of plant-herbivore interaction networks. The novelty of our research lies in the use of a trait-based approach to understand the variation observed in diverse plant-herbivore networks.

Electrochemical behaviour of new dimeric esters and amides derived from caffeic acid in dimethylsulfoxide.

The electrochemical oxidation in DMSO of four new derivatives of caffeic acid (CA), two dimeric amides and two dimeric esters, is reported in this article. Although all of them contain two caffeoyl electroactive moieties in their structures, small differences in the connectors result in interesting changes in the electrochemical behaviour of this type of compound. Voltammograms of both esters do not show appreciable differences between them; however, an electrografting process occurs during the electrochemical oxidation of one of them, which suggests that the identity of the connector has an influence on the ability of the diesters to interact with the electrode surface. On the other hand, voltammograms of dimeric amides were more complex than those corresponding to dimeric esters. Electronic effects of diamine connectors seem to be related to the fact that caffeoyl moieties suffer from separate oxidation processes in both compounds. In contrast to their ferulic acid (FA) analogues, which have been studied by our group before, CA dimeric amides do not interact in an appreciable way with the electrode surface. In addition, a relationship between the oxidation potential and the inhibition percentage of the DPPH (2,2'-diphenyl-1-picrylhydrazyl) radical was not observed for the symmetrical CA derivatives studied here. However, the molecular flexibility seems to play a very important role in the Free Radical Scavenging Activity (FRSA) of this type of compound.

Antibacterial activity of Sonoran propolis and some of its constituents against clinically significant Vibrio species.

The aim of the present study was to evaluate the anti-Vibrio activity of propolis collected from three different areas of the Sonoran Desert in northwestern, Mexico [Pueblo de Alamos (PAP), Ures (UP), and Caborca (CP)]. The anti-Vibrio spp. activity of Sonoran propolis was determined by the broth microdilution method. UP propolis showed the highest antibacterial activity [minimal inhibitory concentration (MIC(50))<50 µg mL(-1)] against Vibrio spp. (UP>CP>PAP). UP propolis significantly inhibited the growth of Vibrio cholerae O1 serotype Inaba (MIC(50)<50 µg mL(-1)), V. cholerae non-O1 (MIC(50)<50 µg mL(-1)), V. vulnificus (MIC(50)<50 µg mL(-1)), and V. cholerae O1 serotype Ogawa (MIC(50) 100 µg mL(-1)), in a concentration-dependent manner. The UP propolis constituents, galangin and caffeic acid phenethyl ester (CAPE), exhibited a potent growth inhibitory activity (MIC(50) 0.05-0.1 mmol l(-1)) against V. cholerae strains (non-O1 and serotype Ogawa). The strong anti-Vibrio activity of Sonoran propolis and some of its chemical constituents (galangin and CAPE) support further studies on the clinical applications of this natural bee product against different Vibrio spp., mainly V. cholerae.

[Evaluation of visual attentional biases in a sample of university smokers]. / Valoración de sesgos atencionales visuales en una muestra de fumadores universitarios.

The tobacco consumption continues being a worrying problem due to the negative consequences in the health. At presents, strategies of prevention based on the persuasion across clue pictures are used, which need to attract the attention of the smoker in order that they are effective. Nevertheless, the number of experimental studies in Spain on attentional biases in smokers is very limited. For it, in this study the aim was to verify the presence of visual attentional biases using the dot probe task in university smokers, stage where the smoking habit is consolidated. The sample was constituted by 337 students of the University of Huelva, with ages between 17 and 30 years. The participation was voluntary and the participants signed an informed assent. 135 subjects presented consumption history, which were distributed, according to classification of the WHO, in daily smokers, occasional smokers and former smokers. A experimental Ex post facto prospective design was used. The results showed that the smokers group was significantly later time to respond to the clue located in the same place that the tobacco picture than the group of not smokers. This shows that the smokers presented more difficulty to disconnect the attention towards smoking cues than not smokers.

Validation of the Curiosity and Exploration Inventory-II in Spanish University Students.

BACKGROUND: This study aimed to analyse the psychometric properties of the Curiosity and Exploration Inventory-II (CEI-II) to provide evidence of validity for its use in research on health promotion and the quality of life of young Spanish university students. METHOD: A sample of 807 participants (75.09% female) aged 18-26 years (M = 20.68; SD = 2.13) completed the CEI-II and health and quality of life measures questionnaire. RESULTS: A unidimensional structure was confirmed, but the original two-dimensional structure also showed an adequate fit. The measures obtained from the CEI-II were gender- and age-invariant, which exhibited adequate internal consistency for both the full scale and subscales, and showed a statistically significant relationship with life satisfaction, sense of coherence, and psychological distress. CONCLUSIONS: The CEI-II can be used as unidimensional, which is recommended, but also as a two-dimensional measure. Both structures provide reliable, valid, and invariant measures across gender and age of exploratory behaviours in Spanish university students. Furthermore, the results confirm the association between exploratory behaviours and greater health management.

Mediterranean Diet, Psychological Adjustment and Health Perception in University Students: The Mediating Effect of Healthy and Unhealthy Food Groups.

This study aims to identify the relationships between eating habits and psychological adjustment and health perception, and to analyze potential mediating role of healthy and unhealthy foods in the relationship between adherence to the Mediterranean diet (MedDiet) and the psychological constructs and health perception. The sample was selected through stratified random cluster sampling and was composed of 788 university students. The participants responded to a MedDiet adherence screener and food consumption inventory to assess the eating habits, instruments measuring self-esteem, life satisfaction, curiosity and sense of coherence to assess the psychological adjustment, and single item measuring perceived health. The results revealed 41.9% of the participants had a high consumption of vegetables and 85.1% a low consumption of energy drinks, while 29.9% showed a high adherence to the MedDiet which was positively associated to each psychological variable and healthy foods and negatively with unhealthy foods. In conclusion, a higher adherence to the MedDiet, and the consumption of fruits and vegetables is related to higher psychological adjustment and health perception. However, the relationships between MedDiet and the psychological variables and health perception were fully or partially explained because of the consumption of healthy and unhealthy foods.

Mesoscopic Modeling of the Encapsulation of Capsaicin by Lecithin/Chitosan Liposomal Nanoparticles.

The transport of hydrophobic drugs in the human body exhibits complications due to the low solubility of these compounds. With the purpose of enhancing the bioavailability and biodistribution of such drugs, recent studies have reported the use of amphiphilic molecules, such as phospholipids, for the synthesis of nanoparticles or nanocapsules. Given that phospholipids can self-assemble in liposomes or micellar structures, they are ideal candidates to function as vehicles of hydrophobic molecules. In this work, we report mesoscopic simulations of nanoliposomes, constituted by lecithin and coated with a shell of chitosan. The stability of such structures and the efficiency of the encapsulation of capsaicin, as well as the internal and superficial distribution of capsaicin and chitosan inside the nanoliposome, were analyzed. The characterization of the system was carried out through density maps and the potentials of mean force for the lecithin-capsaicin, lecithin-chitosan, and capsaicin-chitosan interactions. The results of these simulations show that chitosan is deposited on the surface of the nanoliposome, as has been reported in some experimental works. It was also observed that a nanoliposome of approximately 18 nm in diameter is stable during the simulation. The deposition behavior was found to be influenced by a pattern of N-acetylation of chitosan.

Seasonal Effect on the Biological Activities of Litsea glaucescens Kunth Extracts.

This study shows the seasonal effect on the antioxidant, antiproliferative, and antimicrobial activities of L. glaucescens Kunth (LG) leaves extracts. Their antioxidant activity was evaluated through the DPPH, FRAP, and ORAC assays. Their phenolic content (PC) was determined by means of the Folin-Ciocalteu method, and the main phenolic compounds were identified through a HPLC-DAD analysis. Antiproliferative activity was determined by MTT assay against HeLa, LS 180, M12.C3.F6, and ARPE cell lines. Antimicrobial potential was evaluated against Staphylococcus aureus and Escherichia coli using a microdilution method. All the LG extracts presented high antioxidant activity and PC, with quercitrin and epicatechin being the most abundant. Antioxidant activity and PC were affected by the season; particularly autumn (ALGE) and summer (SULGE) extracts exhibited the highest values (p < 0.05). All extracts presented moderate antiproliferative activity against the cell lines evaluated, HeLa being the most susceptible of them. However, ALGE and SULGE were the most active too. About antimicrobial activity, SULGE (MIC90 < 800 µg/mL; MIC50 < 400 µg/mL), and SLGE (MIC50 < 1000 µg/mL) showed a moderate inhibitory effect against S. aureus. These findings provide new information about the seasonal effect on the PC and biological properties of LG extracts. Clearly, antioxidant activity was the most important with respect to the other two.

1H NMR studies of molecular interaction of D-glucosamine and N-acetyl-D-glucosamine with capsaicin in aqueous and non-aqueous media.

Complex formation of D-glucosamine (Gl) and N-acetyl-D-glucosamine (AGl) with capsaicin (Cp) were studied by 1H NMR titrations in H2O-d2 and DMSO-d6; capsaicin is the major bioactive component of chili peppers. Every titration curve has been interpreted by formulating a suitable model for the reaction equilibrium, to elucidate intermolecular interactions. In DMSO, glucosamine cations associate with each other to yield linear aggregates, and undergo pseudo-1:1-complexation with capsaicin, the formation constant being ca. 30 M-1. N-Acetylglucosamine, without self-association, forms a 2:1-complex AGl2Cp with the stability of ca. 70 M-2. These complexations are achieved by intermolecular hydrogen bonds. In D2O, glucosamine undergoes reversible protonation equilibrium between Gl0 and GlH+ with the logarithmic protonation constants log KD = 8.63 for α-glucosamine and 8.20 for ß-isomer. Both anomeric isomers of deprotonated glucosamine form Gl0Cp-type complexes of capsaicin, in a competitive manner, with a formation constant of 1040 M-1 for the α-glucosamine complex and 830 M-1 for the ß-complex; the anomeric carbons result in the difference in thermodynamic stability. The reactant molecules are closed up by the solvent-exclusion effect and/or the van der Waals interaction; the resulting pair is stabilized by intermolecular hydrogen bonding within a local water-free space between the component molecules. By contrast, neither protonated glucosamine (GlH+) nor N-acetylglucosamine yields a capsaicin complex with the definite stoichiometry. The monosaccharides recognize capsaicin under only a controlled condition; the same phenomena are predicted for biological systems and nanocarriers based on polysaccharides such as chitosan.

Validación de las Escalas Uso Problemático de Medios con Pantallas y su versión corta en población española / Validation of the Problematic Media Use Measure (PMUM) and its short version in the Spanish population

El uso de las Tecnologías de la Información y la Comunicación (TIC) en edades tempranas es cada vez más generalizado. El objetivo de este trabajo fueaportar evidencias de validez y de fiabilidad de la adaptación al español de la Escala de Uso Problemático de Medios con Pantallas (Problematic MediaUse Measure) y su versión corta (Problematic Media Use Measure Short Form). Ambas evalúan el uso problemático de los medios con pantalla enmenores de 4 a 11 años, con la información proporcionada por sus progenitores. La evidencia de validez se basó en el análisis de su estructura internay su relación con otras variables, y la estimación de su fiabilidad se basó en el modelo Omega de McDonald. La muestra consistió en 230 progenitoresde alumnos de dos centros de educación infantil y primaria de la provincia de Huelva (España), con una edad media de 39.58 años (DE = 5.70). Losprogenitores aportaron datos de 230 menores, con edades entre los 4 y los 11 años (M = 8.65; DT = 2.12). De estos, 111 eran niños (48.3%) y116 niñas (50.4%), con tres participantes omitiendo el género. Los resultados, obtenidos mediante un Análisis Factorial Confirmatorio, muestran queambas escalas se ajustan a un modelo unidimensional y cuentan con altos valores de confiabilidad (valor Omega de McDonald de .96 para la escalacompleta y de .90 para la reducida). Se encontró que los dispositivos más utilizados fueron TV, DVD y vídeos, y que su uso se correlacionó positiva ysignificativamente con la preocupación de los padres. Ambas escalas en su versión española se muestran como instrumentos útiles para evaluar el usoproblemático de los medios con pantallas a partir del reporte de los padres. (AU)

The use of information and communication technologies (ICT) at an early age is becoming more widespread. The aim of this work was to provide evidence of validity and reliability ofthe Spanish adaptation of the Problematic Media Use Measure and its short version (Problematic Media Use Measure Short Form). Both evaluatethe problematic media use in children aged 4 to 11 years, by means of the information provided by their parents. The validity evidence was basedon the assessment of its internal structure and its relationship with other variables, and the estimation of its reliability was based on McDonald’sOmega model. The sample consisted of 230 parents of students from two early childhood and primary education centers in the province of Huelva(Spain), with a mean age of 39.58 years (SD = 5.70). Parents provided data on 230 minors, aged between 4 and 11 years (M = 8.65; SD = 2.12).Of these, 111 were boys (48.3%) and 116 girls (50.4%), with three participants omitting gender. The results, obtained by means of a ConfirmatoryFactor Analysis (CFA), shows that both scales fit a unidimensional model and have high reliability values (McDonald’s Omega value of .96 for the fullscale and .90 for the reduced scale). It was found that the most used devices were TV, DVD and videos, and that their use correlated positive andsignificantly with parental concern. Both scales in their Spanish version are shown to be useful instruments for the assessment of the problematicmedia use by means of the parents report. (AU)

Synthesis of new 2-C-(2,3:5,6-di-O-isopropylidene)-beta-D-mannofuranosyldithioacetate derivatives.

Various new C-glycosides have been synthesized through the thioacylation reaction of different amines by a 2-C-mannofuranosyldithioacetate. Amino acids, di- and polyamines (putresceine, spermine, spermidine) and one amino alcohol were in particular used to generate glycothiopeptidic or precursors of "bola" structures.

Relación entre la capacidad adquirida y el riesgo suicida / Relationship between acquired capacity and suicidal risk

La Teoría interpersonal del suicidio señala que la capacidad adquirida hace referencia a que la exposición repetida al dolor conlleva una habituación a estas experiencias, esto es lo que conlleva que el individuo, si cuenta también con la ideación suicida, pueda llevar a cabo el suicidio consumado. Por eso, el objetivo de este estudio es analizar las diferencias en la capacidad adquirida sobre la base de la existencia o no de riesgo suicida. Los resultados avalan los encontrados en otras investigaciones, observándose que, entre las personas con riesgo suicida y sin riesgo, existen diferencias estadísticamente significativas, siendo los que están en riesgo los que obtienen las medias más elevadas. Por lo tanto, la variable capacidad adquirida se muestra como una variable altamente relacionada con el riesgo suicida. (AU)

The Interpersonal Theory of Suicide states that acquired capability refers to the fact that repeated exposure to pain leads to habituation to these experiences, which is what leads the individual, if he or she also has suicidal ideation, to commit suicide. Therefore, the aim of this study is to analyze the differences in the acquired capability on the basis of the existence or not of suicidal risk. The results support those found in other studies, showing that there are statistically significant differences between those at risk and those not at risk, with those at risk having the highest mean scores. Therefore, the acquired capability variable is shown to be a variable highly related to suicidal risk. (AU)

Sonoran propolis: chemical composition and antiproliferative activity on cancer cell lines.

In this study, we have analyzed the chemical composition and antiproliferative activity of propolis from three different arid and semiarid regions of Sonora, Mexico. We identified and quantitated the main chemical constituents of propolis by HPLC-MS. The most abundant constituents of propolis were pinocembrin, pinobanksin 3-acetate, and chrysin. Sonoran propolis had a strong antiproliferative activity on both murine and human cancer cell lines in a concentration-dependent manner. The propolis constituents CAPE, galangin, xanthomicrol and chrysin showed significant antiproliferative activity on most of the cancer cells tested. DNA harvested from cancer cell cultures treated with Sonoran propolis exhibited a ladder of internucleosomal DNA cleavage characteristic of apoptosis. In summary, we have identified and quantitated the main constituents of Sonoran propolis. These propolis samples possess a strong antiproliferative activity on cancer cell lines.

Molecular "compasses" and "gyroscopes." III. Dynamics of a phenylene rotor and clathrated benzene in a slipping-gear crystal lattice.

Samples of 1,4-bis(3,3,3-triphenylpropynyl)benzene 3 were prepared by Pd(0)-catalyzed coupling of 3,3,3-triphenylpropyne (1) and 1,4-diiodobenzene. The structure of compound 3 is such that the central phenylene can play the role of a gyroscope wheel, while the alkyne bond and trityl groups can act as an axle and shielding frameworks, respectively. Crystals grown from benzene and dichloromethane were characterized by X-ray diffraction, variable-temperature (13)C CPMAS NMR, quadrupolar echo solid-state (2)H NMR, and thermal analyses. The rotational dynamics of benzene molecules and phenylene groups were characterized in terms of 6-fold rotation and 2-fold flipping models, respectively. The possibility of a gearing mechanism between adjacent benzene molecules and phenylene groups suggested by the clathrate structure was investigated. However, it was found that 6-fold rotation of benzene molecules at 300 K occurs in the gigahertz regime (or higher) and 2-fold flipping of phenylene groups in the kilohertz range in a structure that can be described as a slipping-gear lattice. The rotational dynamics of the phenylene group in the solvent-free structure were remarkably similar to those in the clathrate, and both are among the fastest known for phenylene rotation in solids. The results presented here provide a valuable starting point for the design and analysis of crystalline solids with correlated molecular motions.

Molecular "compasses" and "gyroscopes". I. Expedient synthesis and solid state dynamics of an open rotor with a bis(triarylmethyl) frame.

We describe our efforts toward the preparation of materials built with molecules possessing topologies analogous to those of macroscopic compasses and gyroscopes. Samples of 1,4-bis(3,3,3-triphenylpropynyl)benzene (3) were prepared by a simple two-step procedure from triphenylmethyl chloride (1) and 1,4-diiodobenzene. The structure of compound 3 is such that the central phenylene can play the role of a gyroscope wheel while the two tritylpropynyl groups can act as an axle and shielding framework. Crystals of a benzene clathrate were characterized by single crystal X-ray diffraction and variable-temperature solid state NMR while their thermal stability was determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The rotational dynamics of the phenylene group in the benzene clathrate and in desolvated samples were characterized in terms of a two-fold flipping process. Solid state rotational barriers of ca. 12.8 and 14.6 kcal/mol were estimated for the benzene clathrate and desolvated samples, respectively.

Molecular compasses and gyroscopes with polar rotors: synthesis and characterization of crystalline forms.

We report the highly convergent synthesis and solid-state characterization of six crystalline "molecular compasses" consisting of a central phenylene rotor with polar substituents, or compass needle, and two trityl groups axially connected by acetylene linkages to the 1,4-positions. Compounds with fluoro-, cyano-, nitro-, amino-, diamino-, and nitroamino substituents are expected to emulate the parent compound which was shown to form crystals where the central phenylene can rotate about its 1,4-axis with rate constants in the 10(3) -10(6) s(-)(1) dynamic ranges near ambient temperature, depending on crystal morphology. With data from single-crystal X-ray diffraction analysis, solid-state CPMAS (13)C NMR, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), it is shown that a relatively small structural perturbation by a single polar group (F, CN, NO(2), NH(2)) results in isomorphous structures with analogous properties. In analogy to the parent compound, crystals grown from benzene formed clathrate structures in the space group Ponemacr; with one molecular compass and two benzene molecules per unit cell. Solvent-free crystals with the same space group obtained by a first-order phase transition between 60 and 130 degrees C were shown to be spectroscopically identical to those obtained by slow solvent evaporation from a mixture of CH(2)Cl(2) and hexanes. A qualitative analysis of the positionally disordered phenylene groups in terms of the expected solid-state rotational dynamics suggests a nonsymmetric, 2-fold rotational potential, or a process involving full 360 degrees turns.

Diagnóstico cultural del ambiente organizacional: un paso previo a la introducción de un sistema de gestión de información / Cultural diagnosis of the organizational environment: a step prior to the introduction of an information management system

La introducción de un sistema de gestión de información en una organización requiere previo a ello, un estudio de su ambiente y cultura con vistas a determinar las posibilidades reales de éxito en este propósito. Es necesario diagnosticar y explorar el ambiente organizacional, sobre todo, desde la perspectiva cultural, para minimizar los riesgos e incertidumbres que implica la introducción de herramientas de corte gerencial como las referidas.

The introduction of an information management system in an organization requires a prior study of its environment and culture in order to determine the real possibilities of success. It is necessary to diagnose and to explore the organizational environment, mainly from the cultural perspective, to minimize the risks and uncertainties implied in the introduction of managerial tools as the above-mentioned.

Valoración de sesgos atencionales visuales en una muestra de fumadores universitarios / Evaluation of visual attentional biases in a sample of university smokers

El consumo de tabaco sigue siendo un problema preocupante debido a las consecuencias negativas que provoca en la salud. Actualmente, están empleándose estrategias de prevención basadas en la persuasión a través de imágenes, las cuales necesitan atraer la atención del fumador para que sean efectivas. Sin embargo, el número de estudios experimentales en España sobre sesgos atencionales en fumadores es muy reducido. Por ello, el objetivo planteado en este estudio fue comprobar la presencia de sesgos atencionales visuales a través de la tarea de detección del punto en fumadores universitarios, etapa donde se consolida el hábito tabáquico. La muestra estuvo formada por 337 estudiantes de la Universidad de Huelva, con edades comprendidas entre los 17 y 30 años. La participación fue voluntaria y efectuada tras firmar un consentimiento informado. Hubo 135 sujetos con historia de consumo, los cuales se distribuyeron, según clasificación de la OMS, en fumadores diarios, fumadores ocasionales y exfumadores. Se utilizó un diseño de tipo Ex post facto prospectivo. Los resultados mostraron que el grupo de fumadores tardaba significativamente más tiempo en responder a las claves estimulares cuando aparecían situadas en el mismo lugar que la imagen relacionada con el tabaco que el grupo de no fumadores. Esto refleja una mayor dificultad a la hora de dejar de prestar atención hacia los estímulos relacionados con el tabaco por parte del grupo fumador con respecto al grupo no fumador (AU)

The tobacco consumption continues being a worrying problem due to the negative consequences in the health. At presents, strategies of prevention based on the persuasion across clue pictures are used, which need to attract the attention of the smoker in order that they are effective. Nevertheless, the number of experimental studies in Spain on attentional biases in smokers is very limited. For it, in this study the aim was to verify the presence of visual attentional biases using the dot probe task in university smokers, stage where the smoking habit is consolidated. The sample was constituted by 337 students of the University of Huelva, with ages between 17 and 30 years. The participation was voluntary and the participants signed an informed assent. 135 subjects presented consumption history, which were distributed, according to classification of the WHO, in daily smokers, occasional smokers and former smokers. A experimental Ex post facto prospective design was used. The results showed that the smokers group was significantly later time to respond to the clue located in the same place that the tobacco picture than the group of not smokers. This shows that the smokers presented more difficulty to disconnect the attention towards smoking cues than not smokers (AU)