A simplified method to estimate Sc-CO2 extraction of bioactive compounds from different matrices: Chili pepper vs. tomato by-products

In the last few decades, the search for bioactive compounds or "target molecules" from natural sources or their by-products has become the most important application of the supercritical fluid extraction (SFE) process. In this context, the present research had two main objectives: (i) to verify the effectiveness of a two-step SFE process (namely, a preliminary Sc-CO2 extraction of carotenoids followed by the recovery of polyphenols by ethanol coupled with Sc-CO2) in order to obtain bioactive extracts from two widespread different matrices (chili pepper and tomato by-products), and (ii) to test the validity of the mathematical model proposed to describe the kinetics of SFE of carotenoids from different matrices, the knowledge of which is required also for the definition of the role played in the extraction process by the characteristics of the sample matrix. On the basis of the results obtained, it was possible to introduce a simplified kinetic model that was able to describe the time evolution of the extraction of bioactive compounds (mainly carotenoids and phenols) from different substrates. In particular, while both chili pepper and tomato were confirmed to be good sources of bioactive antioxidant compounds, the extraction process from chili pepper was faster than from tomato under identical operating conditions

Aligning physical elements with persons' attitude: an approach using Rasch measurement theory

Affective engineering uses mathematical models to convert the information obtained from persons' attitude to physical elements into an ergonomic design. However, applications in the domain have not in many cases met measurement assumptions. This paper proposes a novel approach based on Rasch measurement theory to overcome the problem. The research demonstrates that if data fit the model, further variables can be added to a scale. An empirical study was designed to determine the range of compliance where consumers could obtain an impression of a moisturizer cream when touching some product containers. Persons, variables and stimulus objects were parameterised independently on a linear continuum. The results showed that a calibrated scale preserves comparability although incorporating further variables

Using item response theory to explore the psychometric properties of extended matching questions examination in undergraduate medical education

BACKGROUND: As assessment has been shown to direct learning, it is critical that the examinations developed to test clinical competence in medical undergraduates are valid and reliable. The use of extended matching questions (EMQ) has been advocated to overcome some of the criticisms of using multiple-choice questions to test factual and applied knowledge. METHODS: We analysed the results from the Extended Matching Questions Examination taken by 4th year undergraduate medical students in the academic year 2001 to 2002. Rasch analysis was used to examine whether the set of questions used in the examination mapped on to a unidimensional scale, the degree of difficulty of questions within and between the various medical and surgical specialties and the pattern of responses within individual questions to assess the impact of the distractor options. RESULTS: Analysis of a subset of items and of the full examination demonstrated internal construct validity and the absence of bias on the majority of questions. Three main patterns of response selection were identified. CONCLUSION: Modern psychometric methods based upon the work of Rasch provide a useful approach to the calibration and analysis of EMQ undergraduate medical assessments. The approach allows for a formal test of the unidimensionality of the questions and thus the validity of the summed score. Given the metric calibration which follows fit to the model, it also allows for the establishment of items banks to facilitate continuity and equity in exam standards

Effets du stress oxydatif sur la variabilité du rythme cardiaque

Le stress oxydatif est impliqué dans la genèse de nombreuses pathologies, dont plusieurs maladies cardiaques et circulatoires. De par l'action du monoxyde d'azote, ainsi que des dérivés réactifs de l'oxygène et des antioxydants influençant sa biodisponibilité, sur le système nerveux autonome, le stress oxydatif peut induire certaines pathologies de par son influence sur les fonctions autonomes cardiaques. D'autre part, la variabilité du rythme cardiaque (VRC), une mesure fiable et non invasive, peut facilement être utilisée pour mesurer l'activité du système nerveux autonome au niveau cardiaque. L'objectif de cette étude était d'explorer les liens entre les valeurs de stress oxydatif et de variabilité du rythme cardiaque, par une analyse a posteriori, dans le but de mieux comprendre leurs interactions. Des valeurs de variabilité du rythme cardiaque ont été mesurées sur 270 participants recrutés dans six communautés ripariennes de l'Amazone au Brésil. Des valeurs de monoxyde d'azote, de malondialdehyde, de catalase et de glutathion peroxydase ont aussi été recueillies, en plus de la pression artérielle, du rythme cardiaque et de l'indice de masse corporelle. Nous avons pu observer de faibles corrélations inverses significatives entre le monoxyde d'azote et le SDNN (r = -0,219 p = 0,006), les basses fréquences (ms2) (r = -0,181 p = 0,024) et les très basses fréquences (r = -0,201 p = 0,012) de l'analyse de VRC. Nous avons aussi pu observer une faible corrélation significative entre le malondialdehyde est les très basses fréquences (r = 0,140 p = 0,032). Nous n'avons pu observer aucune corrélation significative entre la catalase, le glutathion peroxydase et les valeurs de VRC. Les résultats ne permettent pas d'atteindre les objectifs fixés, malgré la démonstration de certaines corrélations. L'étude des interactions entre le stress oxydatif demeure toutefois pertinente et des études expérimentales sur une population homogène seraient intéressantes.\ud ______________________________________________________________________________ \ud MOTS-CLÉS DE L’AUTEUR : stress oxydatif, variabilité du rythme cardiaque, antioxydants, monoxyde d'azote, système nerveux autonom

Tutorias de orientación y formación en derecho para estudiantes

Las razones de la renovación del Proyecto de Bienestar Interno fueron los buenos resultados obtenidos en los exámenes parciales y finales por los alumnos que asistieron a las clases de tutorías y las referencias que nos hicieron profesores de años posteriores de los alumnos, que notaron algunos cambios en lo referente al vocabulario, aprendizaje académico y el método de estudio.Fil: Andrich, Agustín. Universidad Católica de Córdoba. Facultad de Educación; Argentin

Kinematics of CO2 fluxes in the tropical Atlantic ocean during the 1983 northern summer

CO2 evasion within the Atlantic equatorial belt (5°N-5°S) increases from the East to the West (Andrié et al., 1986). Many factors contribute the variations of pCO2 in the equatorial surface waters. To assess their relative importance, a kinematic box model is developed. A 2° x 2° box whose depth is defined by the 24.90 °/°° isopcynal level flows westward from 4°W to 38°W within the Equator-2°S band with the south equatorial current. Time (zonal) evolution of nitrate, total CO2, total alkalinity and mass, and of the corresponding water pCO2, are simulated taking into account advection, meridional divergence, diffusion, biological activity and gas exchange. Initial and boundary conditions are taken from the FOCAL 4 (July-August 1983) data se

Ultra-high-frequency left prefrontal transcranial magnetic stimulation as augmentation in severely ill patients with depression: a naturalistic sham-controlled, double-blind, randomized trial

Background and Aim: Repetitive transcranial magnetic stimulation (rTMS) is supposed to be not as effective in severe depression as it is in medium depression. We evaluated the treatment response to an ultra-high-frequency (UHF; 30 Hz) approach, which was used to maximize the rTMS efficacy in severely ill patients. Methods: 43 severely depressed patients were included in the randomized, double-blind study and received either rTMS with 30 Hz over the left dorsolateral prefrontal cortex or sham condition for 3 weeks as an add-on therapy to stable antidepressant medication. Hamilton Depression Rating Scale (HDRS) and cognitive performance were evaluated before and after the intervention. Results: In the active UHF group, the HRDS score was reduced by about 7.2, whereas the sham condition showed a smaller reduction of the HDRS score with 3.9. However, lithium as a covariant was responsible for the outcome difference, not the group of stimulation. No adverse events were reported. Comparing the differences of both groups in the pre- and post-study performance in a trail-making test, a group effect for the UHF group that was not influenced by the lithium intake was observed. Conclusion: A 30-Hz left prefrontal rTMS in severely depressed patients was safe and no adverse events occurred. Due to a strong effect of lithium as a covariate, we could not demonstrate favorable antidepressant effects of the UHF stimulation compared to sham. However, we found an improvement of processing speed performance in the UHF group, which covaried with improvement of psychomotor retardation. Copyright (C) 2012 S. Karger AG, Base

Review: Non-transecting bulbar urethroplasty using buccal mucosa

Augmentation urethroplasty using oral mucosal graft has become the standard surgical treatment of long bulbar strictures. In very tight strictures the urethral plate is narrowed to the extent that an almost circumferential substitution with oral graft is necessary, with suboptimal results. If the obliterative segment within a longer stricture is short it is possible, through a dorsal stricturotomy, to excise it in a non-transecting manner, leaving the ventral spongiosum intact and anastomose the mucosal edges to reconstitute the urethral plate to an adequate calibre. The stricturotomy is subsequently augmented with an oral mucosal graft. We describe this technique as the augmented non-transecting anastomotic bulbar urethroplasty. It also allows for use of a narrower and shorter graft. In our hands this procedure is associated with a 100% radiological success rate and a 95% patient satisfaction rate at a mean follow-up of 14.8 months (5.7–52.6 months).Keywords: Urethral stricture; Bulbar urethroplasty; Non-transecting;Buccal mucosal graf

A Mathematical Model to Evaluate the Kinetics of D-glucose and D-fructose Fermentations by Saccharomyces bayanus at Increasing Ethanol Concentrations

In the cellar, slow and stuck fermentations occurring during winemaking are often successfully solved bythe addition of yeast strains like Saccharomyces bayanus. The kinetic behaviour shown by S. bayanus duringalcoholic fermentation was investigated using a mathematical model previously tested for S. cerevisiae, inorder to show which of the six functional parameters of the model differed significantly with the yeastpopulation. Although some parameters (hexose fractions converted to ethanol and glycerol) did not change,the kinetic constant related to the inactivation rate of the yeast population showed by S. cerevisiae assumeda value significantly higher (approximately 50-fold) than that observed for S. bayanus, while this latterpopulation was ten times less affected by ethanol than S. cerevisiae. Although no remarkable differencescould be found between the ability shown by the two yeast populations to convert hexoses (D-glucose andD-fructose), the tolerance for ethanol accumulation changed strongly. The conversion rate of these twohexoses by S. bayanus was affected less (about ten thousand-fold) by ethanol than that of S. cerevisiae

The Kinetic Effect of Some Wine Components on the Enzymatic Hydrolysis of β-glucan

Enzymatic preparations containing β-glucanases are utilised extensively in winemaking to facilitate the filtration ofmusts and wines coming from grapes affected by Botrytis cinerea, and to induce the release of mannoproteins andoligosaccharides from the cell walls of yeasts. The aim of the present work was to investigate the possible inhibitoryeffect of some wine components, and in particular of ethanol, on β-glucanase activities. For this purpose, the kineticactivity of a commercial enzymatic preparation containing β-glucanases was tested utilising both model solutions(buffer solution having a pH value similar to a must/wine with or without 13% v/v of ethanol added) and a redwine. When ethanol was added to the model solution, both the kinetic constant k and glucose production suffered adecrease of about 50% compared to the values detected in the absence of ethanol. A further loss of activity (about87%) was found using red wine as reaction medium, suggesting, as already reported in the literature, that phenolscould add their inhibitory effect to that of ethanol. The results obtained provide useful suggestions that can beadopted during winemaking. To promote the hydrolysis of the possible excess of β-glucan coming from grapesaffected by Botritis cinerea, it would be more convenient to add β-glucanases before a significant amount of ethanolaccumulates in the must/wine, while it is not possible to avoid the negative impact of ethanol or other possibleinhibitors (phenols) to promote yeast degradation in wine left on lees