The Ringel dual of the Auslander-Dlab-Ringel algebra

The ADR algebra $R_A$ of a finite-dimensional algebra $A$ is a quasihereditary algebra. In this paper we study the Ringel dual $\mathcal{R}(R_A)$ of $R_A$. We prove that $\mathcal{R}(R_A)$ can be identified with $(R_{A^{op}})^{op}$, under certain 'minimal' regularity conditions for $A$. We also give necessary and sufficient conditions for the ADR algebra to be Ringel selfdual.Comment: 25 page

Isolation of polyphenols from spent coffee grounds and silverskin by mild hydrothermal pretreatment

In the present study, a new method for isolation of polyphenols (PP) from spent coffee grounds (SCG) and coffee silverskin (CS) is described. The method consisted in a mild hydrothermal pretreatment at 120 °C, during 20 min, using a liquid to solid ratio of 20 ml/g. PP (determined as gallic acid equivalents, GAE) were the most abundant components in the extracts produced by this method, corresponding to 32.92 mgGAE/gSCG and 19.17 mgGAE/gCS, among of which, flavonoids corresponded to 8.29 and 2.73 mg quercetin equivalents/g of SCG and CS, respectively. Both extracts presented antioxidant activity but the results were higher for SCG extract, probably due to the highest content of PP present. Negligible effects (less than 1% solubilisation) were caused by the hydrothermal pretreatment on cellulose, hemicellulose and protein fractions of these materials. Some minerals elements were present in the extracts, potassium being the most abundant. Hydrothermal pretreatment under mild conditions was demonstrated to be an efficient method to recover antioxidant PP from coffee residues

Hydrothermal pretreatment of spent coffee and silverskin for polyphenols recovery

Coffee is one of the most consumed beverages around the world. As a consequence of this big market, huge amounts of residues are also generated every year as a result of the coffee beans processing. Spent coffee grounds (SCG, Figure 1a), for example, are obtained in significant amounts during the process for instant coffee elaboration, and is also obtained in large amounts in restaurants, bars and cafeterias; while coffee silverskin (CS, Figure 1b) is the main residue obtained during the beans roasting step [1]. Interest in reusing these residues has increased in the last years for economic and environmental concerns. Additionally, such coffee wastes contain in their composition several compounds of interest for application in food, cosmetic and pharmaceutical areas [1]. The presence of polyphenols (PP) in SCG and CS has been reported in several studies, and some technologies have also been proposed for the recovery of these compounds from such coffee residues, among of which the use of organic solvents is usually proposed due to their efficient extraction capacity. However, the use of organic solvents generates a toxic effluent that needs to be treated before discharging to the environment. As an alternative to avoid this problem, the present study evaluated the possibility of recovering PP by hydrothermal pretreatment of SCG and CS. By using this strategy, the residues are submitted to a reaction using only water as extraction solvent under higher temperature conditions than those usually employed for extraction with organic solvents, and the use of these toxic chemicals is avoided. The hydrothermal pretreatment of SCG and CS consisted in using 20 mL of distilled water to each gram of residue, and the reactions were maintained at 120 ºC during 20 min. The total amount of PP in the extracts was quantified as gallic acid equivalents (GAE). The extracts produced under these conditions contained 32.9 mg GAE/g SCG and 19.2 mg GAE/g CS, among of which, flavonoids corresponded to 25% and 14% of the total PP in SCG and CS, respectively. These results were higher than the amounts recovered in previous studies using organic solvents (methanol and ethanol) as extraction agent [2, 3]. It was then concluded that is possible to use a hydrothermal pretreatment to efficiently recover PP from coffee wastes. Further studies will be focused on the selection of the extraction conditions that maximize the recovery results

Consideraciones en torno al Liber Contemplationis in Deum

El objetivo de este breve trabajo ha sido presentar algunas características que nos han llamado la atención del amplísimo Liber Contemplationis in Deum. Estos aspectos son, desde un punto de vista formal, el uso de esquemas, generalmente como paralelismos muy cuidados en todo el Liber; la pasión desbordante que se refleja en la ampulosidad y variedad de adjetivos con los que invoca a Dios; y, sobre todo y subyacente en todo el texto, la continua manifestación de su hondo pesar y de su arrepentimiento como pecador, la necesidad de hacer partícipes de su fe a los infieles yel canto a la esperanza en la misericordia y piedad de Dios, expresado en el punto culminante de los capítulos.The aim of this brief study is to offer some characteristics that have caught our attention in the very broad Liber contemplationis in Deum. These aspects are, from a formal point of view, the use of schemes, generally in the form of very carefully designed parallel patterns throughout the Liber; the overwhelming passion that is reflected in the wealth and variety of adjectives that invoke God; and above all, and underlying all the text, the continuous manifestation of Llull's deep regret and repentance as a sinner, the need to share his faith with infidels and the song of hope andtrust in the mercy and pity of God, which marks the culminating points of each chapter

Considerações a respeito do Liber Contemplationis in Deum

El objetivo de este breve trabajo ha sido presentar algunas características que nos han llamado la atención del amplísimo Liber Contemplationis in Deum. Estos aspectos son, desde un punto de vista formal, el uso de esquemas, generalmente como paralelismos muy cuidados en todo el Liber; la pasión desbordante que se refleja en la ampulosidad y variedad de adjetivos con los que invoca a Dios; y, sobre todo y subyacente en todo el texto, la continua manifestación de su hondo pesar y de su arrepentimiento como pecador, la necesidad de hacer partícipes de su fe a los infieles yel canto a la esperanza en la misericordia y piedad de Dios, expresado en el punto culminante de los capítulos.El objetivo de este breve trabajo ha sido presentar algunas características que nos han llamado la atención del amplísimo Liber Contemplationis in Deum. Estos aspectos son, desde un punto de vista formal, el uso de esquemas, generalmente como paralelismos muy cuidados en todo el Liber; la pasión desbordante que se refleja en la ampulosidad y variedad de adjetivos con los que invoca a Dios; y, sobre todo y subyacente en todo el texto, la continua manifestación de su hondo pesar y de su arrepentimiento como pecador, la necesidad de hacer partícipes de su fe a los infieles yel canto a la esperanza en la misericordia y piedad de Dios, expresado en el punto culminante de los capítulos.The aim of this brief study is to offer some characteristics that have caught our attention in the very broad Liber contemplationis in Deum. These aspects are, from a formal point of view, the use of schemes, generally in the form of very carefully designed parallel patterns throughout the Liber; the overwhelming passion that is reflected in the wealth and variety of adjectives that invoke God; and above all, and underlying all the text, the continuous manifestation of Llull’s deep regret and repentance as a sinner, the need to share his faith with infidels and the song of hope andtrust in the mercy and pity of God, which marks the culminating points of each chapter.El objetivo de este breve trabajo ha sido presentar algunas características que nos han llamado la atención del amplísimo Liber Contemplationis in Deum. Estos aspectos son, desde un punto de vista formal, el uso de esquemas, generalmente como paralelismos muy cuidados en todo el Liber; la pasión desbordante que se refleja en la ampulosidad y variedad de adjetivos con los que invoca a Dios; y, sobre todo y subyacente en todo el texto, la continua manifestación de su hondo pesar y de su arrepentimiento como pecador, la necesidad de hacer partícipes de su fe a los infieles yel canto a la esperanza en la misericordia y piedad de Dios, expresado en el punto culminante de los capítulos