Effect of water velocity on the uptake of polychlorinatedd biphenyls (PCBs) by silicone rubber (SR) and low-density polyethylene (LDPE) passive samplers: an assessment of the efficiency of performance reference compounds (PRCs) in river-like flow conditions

One aim of this study is to determine the impact of water velocity on the uptake of indicator polychlorinated biphenyls (iPCBs) by silicone rubber (SR) and low-density polyethylene (LDPE) passive samplers. A second aim is to assess the efficiency of performance reference compounds (PRCs) to correct for the impact of water velocity. SR and LDPE samplers were spiked with 11 or 12 PRCs and exposed for 6 weeks to four different velocities (in the range of 1.6 to 37.7 cm s−1) in river-like flow conditions using a channel system supplied with river water. A relationship between velocity and the uptakewas found for each iPCB and enables to determine expected changes in the uptake due to velocity variations. For both samplers, velocity increases from 2 to 10 cm s−1, 30 cm s−1 (interpolated data) and 100 cm s−1 (extrapolated data) lead to increases of the uptake which do not exceed a factor of 2, 3 and 4.5, respectively. Results also showed that the influence of velocity decreased with increasing the octanol-water coefficient partition (log Kow) of iPCBs when SR is used whereas the opposite effect was observed for LDPE. Time-weighted average (TWA) concentrations of iPCBs in water were calculated from iPCB uptake and PRC release. These calculations were performed using either a single PRC or all the PRCs. The efficiency of PRCs to correct the impact of velocity was assessed by comparing the TWA concentrations obtained at the four tested velocities. For SR, a good agreement was found among the four TWA concentrations with both methods (average RSD b 10%). Also for LDPE, PRCs offered a good correction of the impact of water velocity (average RSD of about 10 to 20%). These results contribute to the process of acceptance of passive sampling in routine regulatory monitoring programs.

When cholesterol is not cholesterol: a note on the enzymatic determination of its concentration in model systems containing vegetable extracts

Background: Experimental evidences demonstrate that vegetable derived extracts inhibit cholesterol absorption in the gastrointestinal tract. To further explore the mechanisms behind, we modeled duodenal contents with several vegetable extracts. Results: By employing a widely used cholesterol quantification method based on a cholesterol oxidase-peroxidase coupled reaction we analyzed the effects on cholesterol partition. Evidenced interferences were analyzed by studying specific and unspecific inhibitors of cholesterol oxidase-peroxidase coupled reaction. Cholesterol was also quantified by LC/MS. We found a significant interference of diverse (cocoa and tea-derived) extracts over this method. The interference was strongly dependent on model matrix: while as in phosphate buffered saline, the development of unspecific fluorescence was inhibitable by catalase (but not by heat denaturation), suggesting vegetable extract derived H2O2 production, in bile-containing model systems, this interference also comprised cholesterol-oxidase inhibition. Several strategies, such as cholesterol standard addition and use of suitable blanks containing vegetable extracts were tested. When those failed, the use of a mass-spectrometry based chromatographic assay allowed quantification of cholesterol in models of duodenal contents in the presence of vegetable extracts. Conclusions: We propose that the use of cholesterol-oxidase and/or peroxidase based systems for cholesterol analyses in foodstuffs should be accurately monitored, as important interferences in all the components of the enzymatic chain were evident. The use of adequate controls, standard addition and finally, chromatographic analyses solve these issues.

The Banzhaf Value in the Presence of Externalities

[eng] We propose two generalizations of the Banzhaf value for partition function form games. In both cases, our approach is based on probability distributions over the set of possible coalition structures that may arise for any given set of agents. First, we introduce a family of values, one for each collection of the latter probability distributions, defined as the Banzhaf value of an expected coalitional game. Then, we provide two characterization results for this new family of values within the framework of all partition function games. Both results rely on a property of neutrality with respect to amalgamation of players. Second, as this collusion transformation fails to be meaningful for simple games in partition function form, we propose another generalization of the Banzhaf value which also builds on probability distributions of the above type. This latter family is characterized by means of a neutrality property which uses an amalgamation transformation of players for which simple games are closed.

The Banzhaf Value in the Presence of Externalities

[eng] We propose two generalizations of the Banzhaf value for partition function form games. In both cases, our approach is based on probability distributions over the set of possible coalition structures that may arise for any given set of agents. First, we introduce a family of values, one for each collection of the latter probability distributions, defined as the Banzhaf value of an expected coalitional game. Then, we provide two characterization results for this new family of values within the framework of all partition function games. Both results rely on a property of neutrality with respect to amalgamation of players. Second, as this collusion transformation fails to be meaningful for simple games in partition function form, we propose another generalization of the Banzhaf value which also builds on probability distributions of the above type. This latter family is characterized by means of a neutrality property which uses an amalgamation transformation of players for which simple games are closed.

Polarized distribution of inducible nitric oxide synthase regulates activity in intestinal epithelial cells.

Inducible nitric oxide synthase (iNOS) functions as a homodimer. In cell extracts, iNOS molecules partition both in cytosolic and particulate fractions, indicating that iNOS exists as soluble and membrane associated forms. In this study, iNOS features were investigated in human intestinal epithelial cells stimulated with cytokines and in duodenum from mice exposed to flagellin. Our experiments indicate that iNOS is mainly associated with the particulate fraction of cell extracts. Confocal microscopy showed a preferential localization of iNOS at the apical pole of intestinal epithelial cells. In particulate fractions, iNOS dimers were more abundant than in the cytosolic fraction. Similar observations were seen in mouse duodenum samples. These results suggest that, in epithelial cells, iNOS activity is regulated by localization-dependent processes.

Labyrinth de Congost. Disseny i desenvolupament d’un videojoc amb Unity

L’objectiu principal del projecte és la creació d'un prototip de videojoc basat en el joc clàssic Laberint de Congost, utilitzant l’eina de creació de videojocs Unity, per dispositius mòbils i webs.

Prediction of Antibacterial Activity from Physicochemical Properties of Antimicrobial Peptides

Consensus is gathering that antimicrobial peptides that exert their antibacterial action at the membrane level must reach a local concentration threshold to become active. Studies of peptide interaction with model membranes do identify such disruptive thresholds but demonstrations of the possible correlation of these with the in vivo onset of activity have only recently been proposed. In addition, such thresholds observed in model membranes occur at local peptide concentrations close to full membrane coverage. In this work we fully develop an interaction model of antimicrobial peptides with biological membranes; by exploring the consequences of the underlying partition formalism we arrive at a relationship that provides antibacterial activity prediction from two biophysical parameters: the affinity of the peptide to the membrane and the critical bound peptide to lipid ratio. A straightforward and robust method to implement this relationship, with potential application to high-throughput screening approaches, is presented and tested. In addition, disruptive thresholds in model membranes and the onset of antibacterial peptide activity are shown to occur over the same range of locally bound peptide concentrations (10 to 100 mM), which conciliates the two types of observations

Geomorphological mapping of granite zones in the province of Girona (Catalunya, Spain)

Since 1978, the unity of Geodynamics of the University of Girona has been publishing a series of detailed geological and geomorphological maps of different municipal terms of the Province of Girona, mainly on the scale of 1:10.000, situated for the major part in the Littoral and Prelittoral mountain ranges of the Cadena Costera Catalana. These mountain ranges are constituted of materials belonging to the palaeozoic era, basically metamorphous and igneous rocks (plutomc and hypoabyssal rocks)

Funciones termodinámicas relativas a la transferencia del ketoprófen desde el agua hasta algunos sistemas orgánicos

The thermodynamics of molal partitioning of ketoprofen (KTP) was studied in cyclohexane/buffer (CH/W), octanol/buffer (ROH/W), and dimyristoyl phosphatidylcholine (DMPC), dipalmitoyl phosphatidylcholine (DPPC), and egg lecithin (EGG/W) liposome systems. In all cases the partition coefficients (Kmo/w)were greater than unity; therefore the standard free energies of transfer were negative indicating affinity of KTP for organic media. The Kmo/w values were approximately seventy-fold higher in the ROH/W system compared with the CH/W system. On the other hand, the Kmo/w values were approximately ten or fifty-fold higher in the liposomes compared with the ROH/W system. In all cases, the standard enthalpies and entropies of transfer of KTP were positive indicating some degree of participation of the hydrophobic hydration on partitioning processes.

Thermodynamic quantities of solvation and dilution for some acetanilide derivatives in octanol and water mutually saturateds

Based on published thermodynamic quantities for solution, partitioning and sublimation of acetanilide (ACN), acetaminophen (ACP) and Phenacetin (PNC), the thermodynamic quantities for drugs solvation in octanol-saturated water (W(ROH)) and water-saturated octanol (ROH(W)) as well as the drugs dilution in ROH(W) were calculated. The Gibbs energies of solvation were favourable in all cases. The respective enthalpies and entropies were negative indicating an enthalpy-driving for the solvation process in all cases. On the other hand, the Gibbs energies of dilution were favourable for ACP and PNC but unfavourable for ACN, whereas the respective enthalpies and entropies were negative for ACP and PNC but positive for ACN indicating enthalpy-driving for the dilution process in the case of the former drugs and entropy-driving for the latter. From the obtained values for the transfer processes, an interpretation based on solute-solvent interactions was developed.

Modeling of electrolyte sorption – from phase equilibria to dynamic separation systems

In this thesis, general approach is devised to model electrolyte sorption from aqueous solutions on solid materials. Electrolyte sorption is often considered as unwanted phenomenon in ion exchange and its potential as an independent separation method has not been fully explored. The solid sorbents studied here are porous and non-porous organic or inorganic materials with or without specific functional groups attached on the solid matrix. Accordingly, the sorption mechanisms include physical adsorption, chemisorption on the functional groups and partition restricted by electrostatic or steric factors. The model is tested in four Cases Studies dealing with chelating adsorption of transition metal mixtures, physical adsorption of metal and metalloid complexes from chloride solutions, size exclusion of electrolytes in nano-porous materials and electrolyte exclusion of electrolyte/non-electrolyte mixtures. The model parameters are estimated using experimental data from equilibrium and batch kinetic measurements, and they are used to simulate actual single-column fixed-bed separations. Phase equilibrium between the solution and solid phases is described using thermodynamic Gibbs-Donnan model and various adsorption models depending on the properties of the sorbent. The 3-dimensional thermodynamic approach is used for volume sorption in gel-type ion exchangers and in nano-porous adsorbents, and satisfactory correlation is obtained provided that both mixing and exclusion effects are adequately taken into account. 2-Dimensional surface adsorption models are successfully applied to physical adsorption of complex species and to chelating adsorption of transition metal salts. In the latter case, comparison is also made with complex formation models. Results of the mass transport studies show that uptake rates even in a competitive high-affinity system can be described by constant diffusion coefficients, when the adsorbent structure and the phase equilibrium conditions are adequately included in the model. Furthermore, a simplified solution based on the linear driving force approximation and the shrinking-core model is developed for very non-linear adsorption systems. In each Case Study, the actual separation is carried out batch-wise in fixed-beds and the experimental data are simulated/correlated using the parameters derived from equilibrium and kinetic data. Good agreement between the calculated and experimental break-through curves is usually obtained indicating that the proposed approach is useful in systems, which at first sight are very different. For example, the important improvement in copper separation from concentrated zinc sulfate solution at elevated temperatures can be correctly predicted by the model. In some cases, however, re-adjustment of model parameters is needed due to e.g. high solution viscosity.

Defining the art of grammar: Ancient perceptions of γραμματική and grammatical

The subject of this dissertation, which belongs to the field of Classical Philology, are the definitions of the art of grammar found in Greek and Latin sources from the Classical era to the second century CE. Definitions survive from grammarians, philosophers, and general scholars. I have examined these definitions from two main points of view: how they are formed, and how they reflect the development of the art itself. Defining formed part of dialectic, in practice also of rhetoric, and was perceived as important from the Classical era onwards. Definitions of grammar seem to have become established as part of preliminary discussions, located at the beginning of grammatical manuals (tékhnai, artes). These discussions included certain principal notions of the art; in addition to the definition, a list of the parts of the art was also typically included. These lists were formed by two different methods: division (diaíresis, divisio) and partition (merismós, partitio). Many of the grammarians may actually have been unfamiliar with these methods, unlike the two most important scholars of the Late Republic, Varro and Cicero. Significant attention was devoted to the question whether the art of grammar is based on lógos or empeiría. This epistemological question had its roots in medical theories, which were prominent in Alexandria. In the history of the concept of grammatiké or grammatica, three stages become evident. In the Classical era, the Greek term is used to refer to a very concrete art of letters (grámmata); from the Hellenistic era onwards it refers to the art developed by the Alexandrian scholars, a matter of textual and literary criticism. Towards the end of the Hellenistic era, the grammarian also becomes involved with the question of correct language, which gradually begins to appear in the definitions as well.

Rainfall effect on dissipation and movement of diuron and simazine in a vineyard soil

From 2003 to 2007, a field study was performed in a vineyard in Chile to investigate diuron and simazine soil behavior and the effect of additional rainfall. Both herbicides were applied once a year at a rate of 2.0 kg ha-1 a.i. Herbicide concentrations in soil were measured at 0, 10, 20, 40, 90 and 340 days after application, under two pluviometric conditions, natural rainfall and natural rainfall plus irrigation with 180 mm of simulated rainfall during the first 90 days after application. Soil partition coefficient (Kd) varied in the soil profile (0 to 90 cm deep) from 6.75 to 2.04 mL g-1 and from 1.4 to 0.66 mL g-1 and the maximum soil adsorption capacity was approximately 18.3 mg g-1 and 8.3 mg g-1 for diuron and simazine, respectively. Diuron and simazine reached up to 90 and 120 cm of soil depth, with an average of 8.3% and 62.4% of herbicide moved below 15 cm in the soil, respectively. Simazine soil half-life (DT50) was 38.1 days and 7.5 days, whereas the half life for diuron varied from 68.0 and 24.6 for natural rainfall and irrigated, respectively. The average of residual simazine remaining in the whole soil profile after 90 DAA was 25.4% and 39.9% for diuron, with no effect of additional rainfall amount. At 340 DAA the amount of simazine in the whole soil profile corresponded to 13.2% of the initial amount applied, being diuron more persistent with 21.5% of the initial herbicide applied. The high movement in soil of both herbicides could be due to a non-equilibrium sorption process explained by preferential flow, low Kd and high desorption.

Effect of cyproterone acetate on alpha1-adrenoceptor subtypes in rat vas deferens

Gonadal hormones regulate the expression of alpha1-adrenoceptor subtypes in several tissues. The present study was carried out to determine whether or not cyproterone acetate, an anti-androgenic agent, regulates the alpha1-adrenoceptor subtypes that mediate contractions of the rat vas deferens in response to noradrenaline. The actions of subtype selective alpha1-antagonists were investigated in vas deferens from control and cyproterone acetate-treated rats (10 mg/day, sc, for 7 days). Prazosin (pA2 ~9.5), phentolamine (pA2 ~8.3) and yohimbine (pA2 ~6.7) presented competitive antagonism consistent with activation of alpha1-adrenoceptors in vas deferens from both control and treated rats. The pA2 values estimated for WB 4101 (~9.5), benoxathian (~9.7), 5-methylurapidil (~8.5), indoramin (~8.7) and BMY 7378 (~6.8) indicate that alpha1A-adrenoceptors are involved in the contractions of the vas deferens from control and cyproterone acetate-treated rats. Treatment of the vas deferens from control rats with the alpha1B/alpha1D-adrenoceptor alkylating agent chloroethylclonidine had no effect on noradrenaline contractions, supporting the involvement of the alpha1A-subtype. However, this agent partially inhibited the contractions of vas deferens from cyproterone acetate-treated rats, suggesting involvement of multiple receptor subtypes. To further investigate this, the actions of WB 4101 and chloroethylclonidine were reevaluated in the vas deferens from rats treated with cyproterone acetate for 14 days. In these organs WB 4101 presented complex antagonism characterized by a Schild plot with a slope different from unity (0.65 ± 0.05). After treatment with chloroethylclonidine, the complex antagonism presented by WB 4101 was converted into classical competitive antagonism, consistent with participation of alpha1A-adrenoceptors as well as alpha1B-adrenoceptors. These results suggest that cyproterone acetate induces plasticity in the alpha1-adrenoceptor subtypes involved in the contractions of the vas deferens.

Quest/ion of Identities in African American Feminist Postmodern Drama: A Study of Selected Plays by Suzan-Lori Parks

Innovative and unconventional, Pulitzer Prize-winning playwright Suzan-Lori Parks belongs to the continuum of African American playwrights who have contributed to the quest/ion – the quest for and question – of identities for African Americans. Her plays are sites in which the quest/ion of identities for African Americans is pursued, raised and enacted. She makes use of both page and stage to emphasize the exigency of reshaping African Americans’ identities through questioning the dominant ideologies and metanarratives, delegitimizing some of the prevailing stereotypes imposed on them, drawing out the complicity of the media in perpetuating racism, evoking slavery, lynching and their aftereffects, rehistoricizing African American history, catalyzing reflections on the various intersections of sex, race, class and gender orientations, and proffering alternative perspectives to help readers think more critically about issues facing African Americans. In my dissertation, I approach three plays by Parks – The Death of the Last Black Man in the Whole Entire World (1990), Venus (1996) and Fucking A (2000) – from the standpoints of postmodern drama and African American feminism with a focus on the terrains that reflect the quest/ion of identities for African Americans, especially African American women. I argue that postmodern drama and African American feminism provide the ground for Parks to promote the development of a political agenda in order to call into question a number of dominant ideologies and metanarratives with regard to African Americans and draw upon the roles of those metanarratives as a powerful apparatus of racial and sexual oppressions. I also explore how Parks engages with postmodern drama and African American feminism to incorporate her own mininarratives in the dominant discourses. I argue that Parks in these plays uses postmodern drama and African American feminism to encourage reflections on intersectionality in order to reveal the concerns of African Americans, particularly African American women. Her plays challenge the dominant order of hierarchy and patriarchy, while in some cases urging unity and solidarity between African American men and women by showing how unity and solidarity can help them confront race, class and gender oppressions. Furthermore, I discuss how the utilization of postmodern techniques and devices helps Parks to transform the conventional features of playwriting, to create incredulity toward the dominant systems of oppression and to incorporate her mininarratives within the context of dominant discourses.