Gamma Irradiation of Aqueos Solution of L-Aspartic Acid, L-Aspartic Acid in Solid State, and L-Aspartic Acid Adsorbed into Na-Montmorillonite: Its Relevance in Chemistry Prebiotic

Aspartic acid is an amino acid present in the modern proteins, however, is considered a primitive amino acid hence its importance in prebiotic chemistry experiments studies. In some works of prebiotic chemistry have been studied the synthesis and the stability of organic matter under high energy sources, and the role of clays has been highlighted due to clays that can affect the reaction mechanisms in the radiolytic processes. The present work is focused on the study of the role of Namontmorillonite in the gamma radiolysis processes of L-aspartic acid. Gamma radiolysis processes were carried out in three different systems a) L-aspartic acid in aqueous solution; b) L-aspartic acid in solid-state; and c) L-aspartic acid adsorbed into Na-montmorillonite. L-aspartic acid was analyzed by high-performance liquid chromatography−electrospray ionization−mass spectrometry (HPLCESI-MS). The results showed that the decomposition of L-aspartic acid considerably decreased in the presence of clay thus highlighting the protector role of clays and favors the stability of organic matter even under the possible high energy conditions of primitive environments. The principal product ofgamma radiolysis of L-aspartic acid was succinic acid produced by deamination reaction. On the other hand, when aspartic acid was irradiated in solid-state the main product was the L-aspartic acid dimer. Both radiolysis products are important for chemical evolution processes for L-aspartic acid in primitive environments

Stated benefits from urban afforestation in an arid city: a contingent valuation in Mexicali, Baja California, Mexico

The pervasiveness of particulate matter in arid cities has yet to be discussed and tackled. Given that urban trees have been documented to provide air-filtering and dry deposition services, this study documents the stated benefits from an urban afforestation scenario in Mexicali –an arid city located northwest Mexico at the US-Mexico border. Our doublebounded dichotomous contingent valuation protocol yields an estimated average annual willingness to pay (WTP) of USD 88 per household. Variations in the WTP are associated with perception of air quality and presence of respiratory symptoms in the respondent’s household. The smallest WTP (USD 75) is reported by respondents perceiving poor air quality in their neighborhood and with no household members affected by respiratory symptoms. In contrast, respondents perceiving good air quality and with at least one household member facing respiratory symptoms reported a WTP of USD 99. The average stated benefits represent around 0.8% of the annual household income

Applications of Carboxylic Acids in Organic Synthesis, Nanotechnology and Polymers

Carboxylic acids are versatile organic compounds. In this chapter is presented a current overview of the use of carboxylic acids in a different area as organic synthesis, nanotechnology, and polymers. The application carboxylic acids in these areas are: obtaining of small molecules, macromolecules, synthetic or natural polymers, modification surface of nanoparticles metallic, modification surface of nanostructure such as carbon nanotubes and graphene, nanomaterials, medical field, pharmacy, etc. Carboxylic acids can be natural and synthetic, can be extracted or synthesized, presented chemical structure highly polar, active in organic reactions, as substitution, elimination, oxidation, coupling, etc. In nanotechnology, the use of acid carboxylic as surface modifiers to promote the dispersion and incorporation of metallic nanoparticles or carbon nanostructure, in the area of polymer carboxylic acids present applications such monomers, additives, catalysts, etc. The purpose of this chapter is to emphasize the importance of carboxylic acids in different areas, highlighting the area of organic synthesis, nanotechnology and polymers and its applications

Sex Identification of in vitro Plants of Carica papaya L. MSXJ Hybrid through Molecular Markers

Objective: To identify the sex in vitro plants of the MSXJ hybrid papaya (Carica papaya L.) obtained via somatic organogenesis, using molecular markers SCAR type. Design/methodology/approach: Plants of the MSXJ hybrid papaya with eight months of age and during the fruiting stage were collected at the municipality of Cotaxtla, Veracruz. They were superficially disinfected, with plenty of running water, detergent for 30 minutes, 70% alcohol was added for one minute, 30% commercial chlorine for another 30 minutes and rinsed with sterile distilled water. Subsequently the meristems were grown under a MS medium, and after 30 days a subculture was performed. The extraction of DNA was performed using the Doyle and Doyle method. The PCR was done by the Deputy et al. method, and initiators T1, T12 and W11 were used. Results: Initiator T1 was positive control. Initiators T12 and W11 allowed the amplification of fragments identifying hermaphrodite, female and male plants, while the T12 and W11 initiators were specific to hermaphrodite plants. Study limitations/implications: Papaya producers know the genus of plants three months after planting. Sexuality in papaya plants cannot be differentiated until the flowering step. Findings/conclusions: the implementation of molecular markers could facilitate large-scale plant selection, reducing costs, maintenance time and the elimination of plants with unwanted sex.Objective: To identify the sex of in vitro plants of papaya (Carica papaya L.) MSXJhybrid obtained via somatic organogenesis, through SCAR type molecular markers. Design/Methodology/Approach: Eight-month old MSXJ papaya hybrid plants in thefructification stage were collected in Cotaxtla, Veracruz, Mexico. They weresuperficially disinfected with abundant running water, detergent during 30 min, andthen alcohol at 70% was added for one minute, commercial chlorine at 30% for 30min, and they were rinsed with sterile distilled water; then the meristems werecultivated in MS medium and after 30 d a subculture was made. The DNA extractionwas made with the CTAB method, and the DNA PCR was done with the Deputy et al.(2002) method, and the primers T1, T12 and W11 were used.Results: The T1 primer was the positive control and the T12 and W11 primersallowed the amplification of fragments that identify hermaphrodite, feminine and maleplants, while the T12 and W11 primers were specific for hermaphrodite plants.Study Limitations/Implications: It is required to standardize the method for it to beinexpensive.Findings/Conclusions: The sexuality of papaya plants can be differentiated until thestage of flowering, which is why the implementation of molecular markers wouldfacilitate plant selection if it is implemented at a large scale. Costs, maintenance timeand elimination of plants of unwanted sex are reduced this way

Consenso peruano para el uso de la resonancia magnética en el diagnóstico y seguimiento de pacientes con esclerosis múltiple

The use of Magnetic Resonance Imaging (MRI) in the diagnosis and follow-up of patients with Multiple Sclerosis (MS) has optimized the care of the affected patients. Several international working groups have tried to clarify and standardize the global use of MRI but, on many occasions, data are extrapolated from other regions, do not contemplate local realities or are difficult to implement. Objective: To reach a consensus on aspects related to the use of MRI in the diagnosis and follow-up of patients with MS in Peru. Material and Methods: A group of Peruvian experts (neurologists and radiologists) worked on the elaboration of the consensus using a remote survey round methodology. Results: The recommendations, established on the basis of published evidence and on the experts’ criteria, focused on the role of both, the conventional MRI techniques and the measurement of brain atrophy in MS patients both at the time of diagnosis and during the follow-up period. Conclusions: The consensual recommendations could potentially assist in the standardization and optimization of the care and follow-up of patients with MS in our country.El uso de la resonancia magnética (RM) en el diagnóstico y seguimiento de pacientes con esclerosis múltiple (EM) ha optimizado el cuidado de los pacientes afectados. Diversos grupos internacionales de trabajo han intentado clarificar y normatizar el uso global de la RM pero, en muchas ocasiones, se extrapolan datos de otras regiones que no contemplan la realidad de cada lugar o son difíciles de implementar. Objetivo: Consensuar aspectos relacionados con el uso de RM en el diagnóstico y seguimiento de pacientes con EM en el Perú. Material y Métodos: Un grupo de expertos peruanos, conformado por neurólogos y radiólogos, condujo la elaboración del consenso mediante metodología de ronda de encuestas a la distancia. Resultados: Las recomendaciones, basadas en la evidencia publicada y en el criterio de los expertos, enfocaron tanto el rol de las técnicas convencionales de RM como el de la medición de la atrofia cerebral en pacientes con EM al momento del diagnóstico y durante el periodo de seguimiento. Conclusiones: Las recomendaciones del consenso podrán potencialmente homogenizar y optimizar el cuidado y seguimiento de pacientes con EM en nuestro país

Dopamine in the dorsal hippocampus impairs the late-consolidation of cocaine-associated memory

Cocaine is thought to be addictive because it elevates dopamine levels in the striatum, reinforcing drug-seeking habits. Cocaine also elevates dopamine levels in the hippocampus, a structure involved in contextual conditioning as well as in reward function. Hippocampal dopamine promotes the late phase of consolidation of an aversive step-down avoidance memory. Here, we examined the role of hippocampal dopamine function in the persistence of the conditioned increase in preference for a cocaine-associated compartment. Blocking dorsal hippocampal D1-type receptors (D1Rs) but not D2-type receptors (D2Rs) 12 h after a single training trial extended persistence of the normally short-lived memory; conversely, a general and a specific phospholipase C-coupled D1R agonist (but not a D2R or adenylyl cyclase-coupled D1R agonist) decreased the persistence of the normally long-lived memory established by three-trial training. These effects of D1 agents were opposite to those previously established in a step-down avoidance task, and were here also found to be opposite to those in a lithium chloride-conditioned avoidance task. After returning to normal following cocaine injection, dopamine levels in the dorsal hippocampus were found elevated again at the time when dopamine antagonists and agonists were effective: between 13 and 17 h after cocaine injection. These findings confirm that, long after the making of a cocaine-place association, hippocampal activity modulates memory consolidation for that association via a dopamine-dependent mechanism. They suggest a dynamic role for dorsal hippocampal dopamine in this late-phase memory consolidation and, unexpectedly, differential roles for late consolidation of memories for places that induce approach or withdrawal because of a drug association.Fil: Kramar, Cecilia Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Chefer, Vladimir I.. National Institutes of Health; Estados UnidosFil: Wise, Roy A.. National Institutes of Health; Estados UnidosFil: Medina, Jorge Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; ArgentinaFil: Barbano, María Flavia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; Argentin