Heat treatment to modify the structural and physical properties of chitosan-based films Rivero, Sandra G. M.; Garcia, Maria Alejandra; Pinotti, Adriana Noemi This work was focused on studying the changes undergone by heat-treated chitosan films with and without tannic acid addition by monitoring both microstructure and physical properties. Once the films were submitted to different heat treatments, they exhibited higher barrier properties as well as lower water uptake, solubility, and moisture content. These results were also confirmed through X-ray patterns, which changed from the hydrated to the anhydrous conformation, sharper FTIR peaks specifically associated with water, and shift of Tg toward higher temperatures determined by DMA. Moreover, the modifications caused by the curing process at a molecular scale were observed at a structural level by using a TEM technique. FTIR evaluation granted new insights into the interactions between tannic acid and chitosan molecules, before and after the heat curing, especially due to the occurrence of new peaks and changes in the wavenumber region 1550−1750 cm−1.

New Silver Nanosensor for Nickel Traces. Part II: Urinary Nickel Determination Associated to Smoking Addiction Talio, María Carolina; Luconi, Marta Olga; Fernandez, Liliana Patricia A new fluorescence silver nanosensor assisted by surfactant has been recently synthesized and applied to ultra trace nickel determination. The methodology was validated by the standard addition method and satisfactorily applied to nickel determination in urine without previous treatment, coming from subjects with different smoking addiction levels and second hand smokers. Within-day precision was better than 0.011 CV. The reproducibility (between-days precision) was also evaluated over 3 days by performing six determinations each day with a CV of 0.025. The proposed methodology represents a promising approach in the area of biological monitoring due to its low operation cost, simplicity of instrumentation, high sampling speed and non-polluting solvents. Obtained results of urinary nickel concentration were successfully correlated with the tobacco addiction.

Multicomponent click synthesis of potentially biologically active triazoles catalysed by copper nanoparticles on activated carbon in water Alonso, Francisco; Moglie, Yanina Fernanda; Radivoy, Gabriel Eduardo; Yus, Miguel A variety of potentially biologically active 1,2,3-triazoles, derived from (-)-menthol, lactic acid, D-glucose, oestrone, cholesterol, and phenacetin, have been synthesised through the multicomponent alkyne-azide 1,3-dipolar cycloaddition catalysed by copper nanoparticles on activated carbon in neat water.

Automated on-line dispersive liquid-liquid microextraction based on a sequential injection system Andruch, Vasil; Acebal, Carolina Cecilia; Škrlíková, Jana; Sklenářová, Hana; Solich, Petr; Balogh, Ioseph S.; Billes, Ferenc; Kocúrová, Lívia A novel approach for sequential injection-dispersive liquid-liquid microextraction (SI-DLLME) has been suggested. The method is based on the aspiration and mixing of a sample and all required aqueous reagents in the holding coil of an SIA system, delivering it into a conical tube and adding in a mixture of extraction solvent, auxiliary solvent and disperser solvent at high flow rate, resulting in the formation of a cloudy state and the extraction of an analyte. The mixture of extraction and auxiliary solvent is immiscible with water and has a density significantly higher than that of water; consequently, the resulting fine droplets in the mixture, which contain the extracted analyte, are self-sedimented in a short time at the bottom of conical tube. Thus, no centrifugation and no use of a microcolumn are required for separation of the extraction phase. Afterwards, the extracted analyte is aspirated and transferred to a micro-volume Z-flow cell, and the absorbance is measured.The performance of the suggested approach is demonstrated by the SI-DLLME of thiocyanate ions in the form of ion associate with dimethylindocarbocyanine reagent, followed by spectrophotometric detection. A mixture of amyl acetate (as extraction solvent), tetrachloromethane (as auxiliary solvent) and acetonitrile (as disperser solvent) was selected for the DLLME procedure. The appropriate experimental conditions for conventional DLLME and automated SI-DLLME were investigated. The analytical performance of both these procedures was compared. The absorbance of the colored extracts at wavelength 555nm obeys Beer's law in the range of 3.13-28.2 for conventional DLLME and 0.29-5.81mgL-1 of SCN for SI-DLLME, and the limit of detection, calculated from a blank test based on 3s, is 0.110 for conventional DLLME and 0.017mgL-1 for SI-DLLME.

Boundary value problems for anisotropic plates with internal line hinges Grossi, Ricardo Oscar This paper deals with the formulation of an analytical model for the dynamic behaviour of anisotropic plates, with an arbitrary located interal line hinge with elastics supports and piecewise-smooth boundaries elastically restrainded against rotation and translation among other complicating effects. The equations of motion and its associated boundary and transition conditions are derived using Hamilton?s principle. By introducing an adequate change of variables, the energies which correspond to the different elastic restraints, are handled in a general framework. The concept of transition conditions and the determination of the analytical expressions are presented. Analytical examples are worked out to illustrate the range of applications of the developed analytical model. One of the essential features of this work is to demonstrate how the commonly formal derivations, used in the applications of the calculus of variations, can be made rigorous.

José Martí y la Guerra Necesaria Gallegos, Claudio Antonio Estas breves líneas que se encuentran a continuación representan una primera aproximación al sentido de la guerra que desarrolla José Martí en base a sus escritos y accionar en el campo de batalla.

Decreases in Fire Spread Probability with Forest Age Promotes Alternative Community States, Reduced Resilience to Climate Variability and Large Fire Regime Shifts Kitzberger, Thomas; Aráoz, Ezequiel; Gowda, Juan Janakiram Haridas; Mermoz, Mónica Alicia; Morales, Juan Manuel The generalization that plant communities increase in flammability as they age and invariably lead to resilient self-organized landscape mosaics is being increasingly challenged. Plant communities often exhibit rapidly saturating or even hump-shaped age-flammability trajectories and landscapes often display strong non-linear behaviors, abrupt shifts, and self-reinforcing alternative community states. This plethora of fire-landscape interactions calls for a more general model that considers alternative age-flammability rules. We simulated landscape dynamics assuming communities that (1) increase in flammability with age and (2) gain flammability up to a certain age followed by a slight and moderate loss to a constant value. Simulations were run under combinations of ignition frequency and interannual climatic variability. Age-increasing fire probability promoted high resilience to changes in ignition frequency and climatic variability whereas humpbacked-shaped age-flammability led to strong non-linear behaviors. Moderate (20%) reductions in mature compared to peak flammability produced the least resilient behaviors. The relatively non-flammable mature forest matrix intersected by young flammable patches is prone to break up and disintegrate with slight increases in ignition/climate variability causing large-scale shifts in the fire regime because large fires were able to sweep through the more continuous young/flammable landscape. Contrary to the dominant perception, fire suppression in landscapes with positive feedbacks may effectively reduce fire occurrence by allowing less flammable later stage communities composed of longer lived, obligate seeders to replace earlier stages of light demanding, often more flammable resprouters. Conversely, increases in anthropogenic ignitions, a common global trend of many forested regions may, in synergism with increased climate variability, induce abrupt shifts, and large-scale forest degradation.

Comparative toxicity of nanostructured alumina and a commercial inert dust for Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) at varying ambient humidity levels Stadler, Teodoro; Buteler, Micaela; Weaver, David K.; Sofie, Stephen The widespread concern for environmental and human health has raised the need for new reduced-risk control strategies and the search for new chemical classes of pesticides. Recently, a novel type of particulate material, nanostructured alumina (NSA) has been found to induce mortality in insects exposed to wheat treated with NSA dust. Preliminary studies have shown insecticidal activity of NSA particles on two insect species, Sitophilus oryzae (L.), and Rhyzopertha dominica, (F.), major pests of stored grain. We investigated the toxicity of NSA and Protect-It ® diatomaceous earth (DE) using dry dust applications at three different relative ambient humidity levels. Results showed that NSA was more effective in killing S.oryzae than Protect-It ® and was equally toxic to R.dominica. Treatment with both products also reduced progeny production. In addition, R.dominica was less susceptible to inert dusts than S.oryzae. Our results suggest that NSA might prove a good alternative or complement to DE based products, and encourage further testing with other insect pests and systems, plus experiments on delivery options to further enhance NSA products.

Determinants of the DNA binding specificity of class I and class II TCP transcription factors Viola, Ivana Lorena; Reinheimer, Renata; Ripoll, Rodrigo; Uberti Manassero, Nora Graciela; Gonzalez, Daniel Hector TCP proteins constitute a family of plant transcription factors with more than 20 members in angiosperms. They can be divided in two classes based on sequence homology and the presence of an insertion within the basic region of the TCPDNA binding and dimerization domain. Here, we describe binding site selection studies with the class I protein TCP16, showing that its DNA binding preferences are similar to those of class II proteins. Through sequence comparison and the analysis of mutants and chimeras of TCP16, TCP20 (class I), and TCP4 (class II), we established that the identity of residue 11 of the class I TCP domain or the equivalent residue 15 of the class II domain, whether it is Gly or Asp, determines a preference for a class I or a class II sequence, respectively. Footprinting analysis indicated that specific DNA contacts related to these preferences are established with one of the strands of DNA. The dimerization motif also influences the selectivity of the proteins toward class I and class II sequences and determines a requirement of an extended basic region in proteins with Asp-15. We postulate that differences in orientation of base-contacting residues brought about by the presence of either Gly or Asp are responsible for the binding site preferences of TCP proteins. Expression of repressor forms of TCP16 with Asp-11 or Gly-11 differently affects leaf development. TCP16-like proteins with Asp-11 in the TCP domain arose in rosids and may be related to developmental characteristics of this lineage of eudicots.

Dairy products modified in their lactose content Perotti, Maria Cristina; Wolf, Irma Veronica; Vénica, Claudia Inés; Bergamini, Carina Viviana Lactose intolerance is a problem suffered by a large part of the world population. The simplest solution is to remove (partially or completely) dairy products from diet. However, a more convenient alternative from the nutritional viewpoint would be to replace the intake of regular dairy products by others in which the lactose content has been modified. In effect, the dairy products with reduced-lactose and lactose-free contents are examples of added-value products, whose production is targeted to a specific group of consumers. The increased manufacture of these dairy products is driven by the increasing knowledge we have on the lactose intolerance problem. There are different technological methods to modify the lactose content in dairy products, such as enzymatic hydrolysis, ultrafiltration and chromatography. The lactose hydrolysis using β-galactosidases is the strategy most widely used in the industry, making it possible to obtain products with low lactose levels. A wide range of this type of products such as milks, creams, ice-creams and fermented milks, are commercially available around the world. In Latin America, which records a very high incidence of deficient-lactase individuals, there are delactosed products available such as fluid and powder milks and some fermented milks. The consumption of fermented dairy products has undergone a rapid increase in Argentina, where the yogurt is the most popular product. In this context, we are working on different aspects on the production of lactose-hydrolyzed yogurt, as this product is still not available in the Argentinean market. The purpose of this contribution is to review the current knowledge on the lactose intolerance problem and the reducedlactose dairy products, with special emphasis on the applied technological processes. Preliminary results obtained by our research group are also included.

Systematic screening for novel, serologically reactive Hepatitis e Virus epitopes Ostermann Porcel, María Victoria; Vizoso Pinto, María Guadalupe; Haase, Rudolf; Nitschko, Hans; Jaeger, Simone; Sander, Michaela; Motz, Manfred; Mohn, Ulrich; Baiker, Armin Background: The National Institutes of Health classified Hepatitis E as an emerging disease since Hepatitis E Virus (HEV) is the major cause of acute hepatitis in developing countries. Interestingly, an increasing number of sporadic cases of HEV infections are described in industrialized countries as zoonosis from domestic livestock. Despite the increasing relevance of this pathogen in clinical virology, commercial antibody assays are mainly based on fragments of HEV open reading frame (ORF) 2 and ORF3. The largest ORF1 (poly-)protein, however, is not part of current testing formats. Methods. From a synthesized full length HEV genotype 1 cDNA-bank we constructed a complete HEV gene library consisting of 15 respective HEV ORF domains. After bacterial expression and purification of nine recombinant HEV proteins under denaturating conditions serum profiling experiments using 55 sera from patients with known infection status were performed in microarray format. SPSS software assessed the antigenic potential of these nine ORF domains in comparison to seven commercial HEV antigens (genotype 1 and 3) by performing receiver operator characteristics, logistic regression and correlation analysis. Results: HEV antigens produced with our method for serum profiling experiments exhibit the same quality and characteristics as commercial antigens. Serum profiling experiments detected Y, V and X domains as ORF1-antigens with potentially comparable diagnostic significance as the well established epitopes of ORF2 and ORF3. However no obvious additional increase in sensitivity or specificity was achieved in diagnostic testing as revealed by bioinformatic analysis. Additionally we found that the C-terminal domain of the potential transmembrane protein ORF3 is responsible for IgG and IgM seroreactivity. Data suggest that there might be a genotype specific seroreactivity of homologous ORF2-antigens. Conclusions: The diagnostic value of identified ORF1 epitopes might not necessarily improve sensitivity and specificity, but broaden the overall quality of existing test systems. ORF2 and ORF3-antigens are still commonly used in diagnostic assays and possibly hold the potential to serologically differentiate between genotype 1 and 3 infections. Our systematic approach is a suitable method to investigate HEV domains for their serologic antigenicity. Epitope screening of native viral domains could be a preferable tool in developing new serologic test components.

Electronic excited states of protonated aromatic molecules: Protonated Fluorene Alata, Ivan; Broquier, Michel; Dedonder, Claude; Jouvet, Christophe; Marceca, Ernesto José The photo-fragmentation spectrum of protonated fluorene has been recorded in the visible spectral region, evidencing an absorption that appears largely red shifted in comparison to that of the neutral molecule fluorene. The spectrum shows two different vibrational progressions, separated by 0.19 eV. As in the case of protonated linear polycyclic aromatic hydrocarbons (PAHs), comparison of the measured spectra with ab initio calculations allows to associate the observed absorption shift with the charge transfer character of the excited state. The spectra can be properly simulated by geometry optimization of the ground and excited states, followed by Franck Condon analysis. The two vibrational bands progressions observed are assigned, with relatively good confidence, to the existence of two different conformers. © 2011 Elsevier B.V. All rights reserved.

Vascular hyporeactivity to angiotensin II and noradrenaline in a rabbit model of obesity Jerez, Susana Josefina; Scachi, Fabricio; Sierra, Liliana; Karbiner, María Sofía; Peral, Maria de Los Angeles This study was conducted to explore the vascular reactivity of angiotensin II and noradrenaline and their relationship with endothelial function in rabbits fed a high-fat diet (HFD). The animals were fed either an HFD or regular chow [control diet (CD)]. After 12 weeks, the rabbits fed the HFD showed higher blood pressure, body weight, and insulin levels. Glucose tolerance was impaired and positively related to blood pressure. An endothelium-independent decrease of the sensitivity to angiotensin II [pD 2 endothelium-intact aortic rings (E+) in CD: 8.02 ± 0.07 vs. HFD: 7.60 ± 0.01; pD 2 endothelium-removed aortic rings (E-) in CD: 8.16 ± 0.11 vs. HFD: 7.83 ± 0.16] and noradrenaline (pD 2 E+ in CD: 6.36 ± 0.06 vs. HFD: 5.29 ± 0.06; pD 2 E- in CD: 6.11 ± 0.08 vs. HFD: 5.80 ± 0.08) was found. Noradrenaline desensitized the angiotensin II response (pD 2 with noradrenaline pretreatment in E+: 7.03 ± 0.16; in E-: 7.10 ± 0.02), but angiotensin II did not change the noradrenaline response. Acetylcholine maximal relaxation and basal nitric oxide (NO) release were comparable in both diet groups. The efficacy of angiotensin II (R max CD: 4604 ± 574 mg vs. HFD: 3251 ± 533 mg) and noradrenaline (R max CD: 11,675 ± 804 mg vs. HFD: 7975 ± 960 mg) was reduced in E+. L-N G-nitroarginine methyl ester (L-NAME) recovered the efficacy of noradrenaline (R max L-NAME: 12,015 ± 317 mg). In contrast, L-NAME had no effect on the angiotensin II response. Noradrenaline enhanced NO levels, but angiotensin II did not. Therefore, NO was associated with hyporeactivity to noradrenaline. The resting potential was more negative in E+, and the endothelium diminished the angiotensin II-induced depolarization. These findings demonstrated that the crosstalk and the endothelium may induce hyporeactivity to angiotensin II and noradrenaline as a mechanism to compensate the increase in the blood pressure in HFD-induced obesity.

Cobalt nanoparticles on mesoporous MCM-41 and Al-MCM-41 by Supercritical CO2 Deposition Aspromonte, Soledad Guadalupe; Sastre, Alvaro; Boix, Alicia Viviana; Cocero, María José; Alonso, Esther CoO and Co3O4 nanoparticles were uniformly dispersed inside mesoporous MCM-41 and Al-MCM-41 supports using supercritical CO2 reactive deposition. This method represents a one-pot reproducible procedure that allows the dissolution of the organocobalt precursor and supports impregnation in supercritical CO2 at 70 °C and 110 bar, followed by the precursor thermal decomposition into cobalt species at 200 °C and 160 bar. By the relative concentration of the cobalt precursor [cobalt (II) bis (η5-ciclopentadienil)], the load of cobalt nanoparticles was controlled and then determined by Inductively Coupled Plasma (ICP-OES). The synthesis of CoO and Co3O4 species inside the MCM-41 and Al-MCM-41 substrates was confirmed by X-ray Photoelectron (XPS) and Laser Raman Spectroscopies (LRS). By N2 adsorption and Small Angle X-ray Scattering (SAXS), it was determined that the hexagonal arrangement as well as the surface area and pore size of the substrates changed after the addition of cobalt. By means of X-ray mapping from SEM images, a homogeneous distribution of cobalt nanoparticles was observed inside the mesopores when the cobalt loading was 1 wt.%. In addition, spherical cobalt nanoparticles of average diameter close to 20 nm were detected on the outer surface of MCM-41 and Al-MCM-41 supports when the cobalt content was higher. On the other hand, by Transmission Electron Microscopy (TEM), it was possible to measure the interplanar distance of the crystalline plane of the outer nanoparticles, which was later compared with the theoretical distance values which allowed identifying the CoO and Co3O4 phases.

Análisis de la dinámica costera vinculada a la urbanización: los casos de Playa Unión y Playa Magagna (Provincia de Chubut, Patagonia, Argentina); Coastal dynamics analysis related to urbanization: the cases of Playa Unión and Playa Magagna (Chubut province, Patagonia, Argentina) Ferrari, María Paula Dentro de las principales actividades antrópicas que impactan o transforman el ambiente natural se encuentra el proceso de urbanización, y el ambiente costero no está exento de estas intervenciones. En la dinámica costera no sol o intervienen procesos naturales sino también actuaciones humanas, ambos generadores de condiciones de peligro. Si bien existen en Playa Unión y Playa Magagna (Provincia de Chubut, Patagonia Argentina) condiciones de peligrosidad natural vinculadas a procesos geomorfológicos, en los últimos años se ha registrado una creciente ocupación del espacio para urbanización que ha generado diversas transformaciones territoriales en el ambiente costero, acentuando los procesos de peligrosidad natural ya existentes en el área de estudio. El objetivo del trabajo es caracterizar los procesos de la dinámica costera que generan condiciones de peligro en las costas de Playa Unión y Playa Magagna. Para dicha caracterización se articuló el trabajo de campo y la indagación bibliográfica.; The process of urbanization is one of the main human activities that impact or transform the natural environment, and the coastal environment is not exempt from these interventions. Coastal dynamic processes involve not only natural but also human actions, both yielders of hazardous conditions. Eve n though in Playa Unión and Playa Magagna (Chubut Province, Patagonia Argentina) exist natural hazard conditions related to geomorphological processes, recent years have experimented an increasing use of space for urbanization, which developed several territorial changes in the coastal environment accentuating the natural hazard process existing in the study area. The objective of this studio is to characterize the dynamic coastal processes that generate hazardous conditions in the shores of Playa Unión and Playa Magagna. This characterization was based on field-work, literature and document research.

Discurso, neoliberalismo y educación: la precarización laboral de los docentes. Revisando los ´90 Carrizo, Gabriel Alejandro Este artículo está dedicado al análisis del discurso del neoliberalismo pedagógico, que adquirió una presencia hegemónica durante los ´90, y que tenía como objetivo re definir la identidad laboral, al promover la figura de un docente posfordista, flexible, autónomo y disciplinado. Posteriormente, mostraremos que dicho discurso legitimó determinadas políticas que afectaron la condición laboral del colectivo docente, en el marco de una creciente precarización laboral.

Perdonar setenta veces siete: procesos de conformación y transformación de subjetividades juveniles en una iglesia pentecostal del conurbano bonaerense; Forgiving seventy times seven: formation and transformation processes of youth subjectivities in a Pentecostal church of Buenos Aires metropolitan area Mosqueira, Mariela Analía Este trabajo presenta una aproximación a los procesos de conformación y transformación de subjetividades juveniles al interior de comunidades pentecostales. En particular, se vincularán, a través de una experiencia etnográfica, las dimensiones analíticas consideradas para el estudio de la subjetividad: habitus, sensibilidades (corporalidades, embodiment, emociones), procesos de socialización como prácticas rituales y relaciones sociales/intersubjetividad.; Este artigo apresenta uma abordagem dos processos de formação e transformação das subjetividades de jovens em comunidades evangélicas pentecostais. Serão particularmente relacionadas, através de uma experiência etnográfica, as dimensões analíticas utilizadas para o estudo da subjetividade, habitus, sensibilidades (corpo, embodiment, emoções), processos de socialização como práticas rituais e relações sociais/intersubjetividade.; This paper presents an approach to the processes of formation and transformation of youth subjectivities within Pentecostal-Evangelical communities. The analytical dimensions considered for the study of subjectivity will be particularly linked through an ethnographic experience: habitus, sensitivities (body, embodiment, emotions), processes of socialization as ritual practices, and social relations/intersubjectivity.

Derechos, luchas y políticas públicas: la seguridad social en Estados Unidos en la década de 1960; Rights, struggles and public policies: social security in the United States during the sixties Dvoskin, Nicolás La década de 1960 es uno de los momentos más interesantes de la historia estadounidense en materia de luchas sociales. Conflictos de raza y de clase se entrecruzaron configurando un permanente clima de movilización social, al tiempo que los consensos económicos de la inmediata posguerra empezaron a encontrar sus límites. Entendiendo a los derechos sociales como consecuencias de procesos de lucha y, sobre todo, como válidos en tanto socialmente legítimos, en este trabajo se estudia la conformación de la seguridad social ampliada en esta década en clave de su relación con las luchas y conflictos de aquellos tiempos. Con especial énfasis en el proceso de creación de los programas de salud, pero también reconociendo la notable transformación de la cobertura de ingresos para la vejez, en el presente trabajo se subraya que los sesenta muestran a las claras cómo los modelos de integración de tipo fordista necesariamente presentan grietas al implementarse en sociedades desiguales, donde sus beneficios no llegan a todos. De este modo, una seguridad social ampliada surge como respuesta a las insuficiencias del modelo contributivo fordista, pero a la vez choca con límites propios de la idiosincrasia social del país. Causas, desarrollo y límites de la seguridad social de los sesenta son estudiados aquí, siempre en la clave de pensar a los derechos, ante todo, como conquistas sociales; es decir, como el resultado de un proceso de luchas, materiales e ideológicas a la vez; The 1960 decade is one of the most interesting moments of American history in terms of social struggles. Race and class conflicts linked each other, creating a permanent climate of social mobilization. Meanwhile, the economic consensus of the immediate postwar period began to find its limits. Understanding social rights as consequences of struggles and, above all, as valid only if socially legitimate, in this paper there is a study of the formation of extended social security during this decade, in terms of its relationship with the struggles and conflicts that arose during those years. With a special attention on the creation of health insurance programs, but also recognizing the remarkable transformation of the elderly income coverage, in this paper it is stressed that the sixties show the way how Fordist-typed integration models necessarily present weaknesses when implemented in unequal societies, where their benefits do not reach everyone. This way, an extended social security arises as a government response to the insufficiencies of the Fordist cotributive model, but at the same time crashes with the limits imposed by the traditional American ways. Causes, development and limits of the 60´s social security are studied here, always in terms of thinking rights, above all, as social conquests. This means, as the result of a struggle process, material and ideological all at once.

Flavonoids as GABAA receptor ligands: the whole story? Wasowski, Cristina Lucia N.; Marder, Nora Mariel Benzodiazepines are the most widely prescribed class of psychoactive drugs in current therapeutic use, despite the important unwanted side effects that they produce, such as sedation, myorelaxation, ataxia, amnesia, and ethanol and barbiturate potentiation and tolerance. They exert their therapeutic effects via binding to the benzodiazepine binding site of gamma-aminobutyric acid (GABA) type A receptors, and allosterically modulating the chloride flux through the ion channel complex. First isolated from plants used as tranquilizers in folkloric medicine, some natural flavonoids have been shown to possess selective affinity for the benzodiazepine binding site with a broad spectrum of central nervous system effects. Since the initial search for alternative benzodiazepine ligands amongst the flavonoids, a list of successful synthetic derivatives has been generated with enhanced activities. This review provides an update on research developments that have established the activity of natural and synthetic flavonoids on GABA type A receptors. Flavonoids are prominent drugs in the treatment of mental disorders, and can also be used as tools to study modulatory sites at GABA type A receptors and to develop GABA type A selective agents further.

Functional characterization of dI6 interneurons in the neonatal mouse spinal cord Dyck, Jason; Lanuza, Guillermo Marcos; Gosgnach, Simon Our understanding of the neural control of locomotion has been greatly enhanced by the ability to identify and manipulate genetically defined populations of interneurons that comprise the locomotor central pattern generator (CPG). To date, the dI6 interneurons are one of the few populations that settle in the ventral region of the postnatal spinal cord that have not been investigated. In the present study, we utilized a novel transgenic mouse line to electrophysiologically characterize dI6 interneurons located close to the central canal and study their function during fictive locomotion. The majority of dI6 cells investigated were found to be rhythmically active during fictive locomotion and could be divided into two electrophysiologically distinct populations of interneurons. The first population fired rhythmic trains of action potentials that were loosely coupled to ventral root output and contained several intrinsic membrane properties of rhythm-generating neurons, raising the possibility that these cells may be involved in the generation of rhythmic activity in the locomotor CPG. The second population fired rhythmic trains of action potentials that were tightly coupled to ventral root output and lacked intrinsic oscillatory mechanisms, indicating that these neurons may be driven by a rhythm-generating network. Together these results indicate that dI6 neurons comprise an important component of the locomotor CPG that participate in multiple facets of motor behavior.