Permeability of Human Tooth Surfaces Studied In Vitro by Electrochemical Impedance Spectroscopy

Electrochemical Faradaic impedance spectroscopy was applied to evaluate dependence of the electrical resistance on human teeth. The experiments were performed using iodide anions as a redox probe to model permeability of teeth for fluoride upon an iontophoresis process. Tooth molars were used - as these are teeth most affected by tooth decay processes in vivo. Teeth compared included sound molars - with no evidence of pit and fissure decay, teeth with pits and fissures regarded 'clinically' as showing signs of decay, and teeth with crowns removed to present exposed dentin surfaces. A difference of more than an order of magnitude in electrical resistance was observed between sound molars and those regarded as showing evidence of tooth decay processes. Sound dentin, as expected from structural considerations demonstrated significantly lower resistance when compared to sound molars. Importantly, the difference in tooth resistance measured between carious and sound molars was shown to be much more representative of their structural integrity than comparison of digitally processed images of the teeth. The results support the utility of electrochemical Faradaic impedance spectroscopy for the development of understanding on how tooth electrical resistance may vary according to structural changes. This understanding may be useful to continued refinements in the use of electrical resistance measures as caries diagnostics and support generically the potential for iontophoretic processes in in-office fluoride treatments of teeth. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.This research was supported by Procter and Gamble Company in the frame of the project “Instigation of Charged Species Delivery in Oral Cavity via Iontophoresis”. The authors acknowledge the assistance and support of Mr. James Zoladz in selection and preparation of tooth specimens for analysis.Peer Reviewe

Propiedades físicas de suelos sódicos, su impacto en el crecimiento y absorción radical en el cultivo de maíz (Zea mays L.)

Trabajo Final (Especialización en Producción de Cultivos Extensivos) -- UNC- Facultad de Ciencias Agropecuarias, 2017El presente trabajo tiene por finalidad analizar algunas propiedades de los suelos sódicos de textura franca o más fina que normalmente limitan el crecimiento e indirectamente el rendimiento del cultivo de maíz. El problema de suelos salinos y sódicos es generalizado a nivel mundial y su superficie está en crecimiento. En particular, las áreas aledañas a la laguna de Mar Chiquita tienen una importante presencia de suelos salinos y sódicos que no han sido estudiados en detalle. Por lo tanto, la zona de estudio de este trabajo se centra en esa geografía. Los suelos se diagnosticaron a través de mediciones de parámetros físicos (resistencia mecánica, humedad actual, infiltración, densidad aparente) y químicos (materia orgánica, conductividad eléctrica del extracto de saturación, pH, cationes intercambiables, NT, N-NO 3- ). Los valores de los parámetros medidos coinciden con la literatura en indicar que la conductividad hidráulica y a la resistencia mecánica son las principales limitantes del normal crecimiento del cultivo en estas situaciones. Estos resultados destacan la necesidad de medir más exhaustivamente las principales propiedades físicas de suelos salinos y sódicos, así como también la importancia de ajustar la disponibilidad hídrica dado que esta podría ser inferior a la supuesta, teniendo esto un impacto en el manejo del cultivo. Se analizaron además las siguientes medidas para mitigar esta problemática: el impacto de aplicaciones de enmiendas (yeso) sobre la conductividad hidráulica (la cual puede aumentar transitoriamente o no variar de manera sustancial) y la utilización de reservas hídricas del suelo por parte del cultivo, factor directamente relacionado a variaciones de la conductividad hidráulica. Se estudió también la utilización de herramientas de remoción (arado de Paratil) lo cual redujo la resistencia mecánica en los suelos sódicos notablemente, teniendo esto un impacto directo en el crecimiento del cultivo. Cómo futura línea de investigación de técnicas de mitigación de suelos salinos y sódicos se plantea analizar el impacto positivo de la fertilización en el desarrollo de raíces y diferencias intraespecíficas de longitud radical las cuales podrían ser tenidas en cuenta en un plan de mejoramiento genético, ya que podrían tener un impacto productivo, considerando que un híbrido con mayor desarrollo de raíces es capaz de explorar mayor profundidad del perfil de suelo y por lo tanto disponer de mayor cantidad de agua.The objective of this work was to analyze some properties of loamy or fine-textured sodic soils that normally constrain the growth and indirectly the yield of maize crops. The problem posed by saline and sodic soils is widespread worldwide and its extent keeps growing. In particular, the areas around the Mar Chiquita lagoon have an important presence of saline and sodic soils which have not been studied in detail. Therefore, the study area of this work focuses on that geography. Soils were characterized by measuring physical (mechanical strength, real humidity, infiltration, bulk density) and chemical parameters (organic matter, saturation extract electrical conductivity, pH, exchangeable cations, NT, N-NO3-). The values of the measured parameters coincide with the literature in indicating that the soils’ hydraulic conductivity and the mechanical resistance are the main limits to the normal growth of crops in this situation. The parameter values obtained coincide with the literature in that the hydraulic conductivity and the mechanical resistance are the main limiters of the normal growth of the crop in this situation. The following mitigation measures were analyzed: the impact of applications of amendments (gypsum) on hydraulic conductivity (which may transitorily increase or remain substantially invariable), and the crop’s use of soil water reserves, which is factor directly related to variations in hydraulic conductivity. The application of break up tools (Paratill plow) reduced the mechanical resistance in the sodium soils significantly, which had a direct correlation with crop growth. Future lines of investigation in mitigation techniques for saline and sodic soils include analysis of the influence of fertilization on root development and on intraspecific differences of radical length in a genetic improvement plan. This could have a productive impact considering that a hybrid with larger root development is able to explore a larger soil depth and therefore have access to more water

Optimization of Enzymatic Logic Gates and Networks for Noise Reduction and Stability

Biochemical computing attempts to process information with biomolecules and biological objects. In this work we review our results on analysis and optimization of single biochemical logic gates based on enzymatic reactions, and a network of three gates, for reduction of the "analog" noise buildup. For a single gate, optimization is achieved by analyzing the enzymatic reactions within a framework of kinetic equations. We demonstrate that using co-substrates with much smaller affinities than the primary substrate, a negligible increase in the noise output from the logic gate is obtained as compared to the input noise. A network of enzymatic gates is analyzed by varying selective inputs and fitting standardized few-parameters response functions assumed for each gate. This allows probing of the individual gate quality but primarily yields information on the relative contribution of the gates to noise amplification. The derived information is then used to modify experimental single gate and network systems to operate them in a regime of reduced analog noise amplification.Comment: 7 pages in PD

Urbanidades criativas

O objetivo desta dissertação é analisar a forma como a criatividade pode, em consonância com a arquitetura, ser um mecanismo de reestruturação urbana. Com este pensamento é desenvolvido um esforço de relacionar os conceitos de Criatividade, Cultura e Indústrias Criativas. As cidades atuais não consistem, somente, num conjunto de edifícios e num determinado número de habitantes e serviços que as compõem. Estas, entre si, praticam diferentes papéis culturais, económicos, sociais e arquitetónicos que definem os diferentes potenciais criativos de cada uma. Começando nos EUA, em 1988, este tipo de pensamentos espalhou-se para o Reino Unido, e já em 1990 tinha chegado à Austrália, acabando por se alastrar um pouco por todo o mundo, com principal influência nas principais cidades ou capitais económicas. Esta mudança do pensamento urbano está aliada a fatores de desenvolvimento socioeconómico e ao surgimento de diferentes superpotências mundiais. A abordagem de diferentes visões e definições sobre a prática da temática “cidade criativa”, que poderá incluir palavras-chave como “criatividade”, “indústrias criativas” e “creative milieux”, vem ao encontro dos últimos anos de desenvolvimento urbanístico do nosso país, Portugal. Não poderíamos deixar de referir os principais desafios da temática, em termos de orientações políticas e práticas urbanas, que por consequência nos transporta para uma contextualização da situação portuguesa, a partir de alguns casos de referência com sucesso internacional e alguns casos nacionais que recentemente começaram a emergir. A revisão bibliográfica aplica-se ao estudo e à observação direta dos referidos espaços. Pretende-se chegar à conclusão que os vazios urbanos e os espaços históricos devolutos fazem parte do património e podem proporcionar aos habitantes um contacto mais próximo com a cultura e história locais. Presume-se que, transformar estes espaços em “clusters criativos” se podem abrir as portas para uma panóplia de diferentes áreas de expressão. O projeto teórico-prático criado abordará diferentes vertentes potenciais destas transformações: ambientais, estéticas, culturais, sociais e económicas. O estudo da proposta surge de uma experiência pessoal vivida na Polónia no âmbito do programa ERASMUS. E, remete-nos para a ideia de criar um volume vazio dentro do edifício já existente, mas expectante. Este irá ser transportado para o exterior dando vida a uma nova estrutura que tem como propósito receber os visitantes. A essência será revitalizar esta área outrora habitada, com a criação de espaços de caráter cultural, artístico e empresarial.The aim of this work is to analyze how creativity can, in line with the architecture, be a urban restructuring mechanism. With this thought is developed an effort to relate the concepts of creativity, culture and creative industries. Current cities do not consist only in a series of buildings and a number of inhabitants and services, which are composed. These practice among themselves different cultural, economic, social and architectural roles defining the different creative potentials of each. Starting in the US in 1988, this type of thoughts spread to the UK, and already in 1990 had come to Australia and eventually spread all over the world, with major influence in cities or economic capitals. This change of urban thinking is combined with socio-economic development factors and the emergence of different cities across the globe. The approach of different views and definitions of the practice of thematic "creative city", which may include keywords like "creativity", "creative industries" and "creative milieux" meets the last few years of urban development of our country, Portugal. We could not fail to mention the main challenges of the subject, in terms of policy guidelines and urban practices, which consequently takes us to a contextualization of the Portuguese situation, from some case studies with international success and some national cases that have recently begun to emerge. The bibliographical review applies to the study and direct observation of the space. The aim is to reach the conclusion that urban voids and vacant spaces are part of the historical heritage and can provide residents a closer contact with the local culture and history. It is assumed that transformation of these spaces in "creative clusters" can open the door to a range of different areas of expression. The theoretical and practical design created address different aspects of these potential changes: environmental, aesthetic, cultural, social and economic. The study of the proposal arises from a personal experience lived in Poland under the ERASMUS program. And brings us to the idea of creating a void volume within the existing building. This will be transported outside giving life to a new structure that aims to get visitors. The essence will revitalize this once inhabited area with the creation of spaces of cultural character, artistic and business

Laccase-modified gold nanorods for electrocatalytic reduction of oxygen

The multicopper oxidase Trametes hirsuta laccase (ThLc) served as a bioelectrocatalyst on nanostructured cathodes. Nanostructuring was provided by gold nanorods (AuNRs), which were characterized and covalently attached to electrodes made of low-density graphite. The nanostructured electrode was the scaffold for covalent and oriented attachment of ThLc. The bioelectrocatalytic currents measured for oxygen reductionwere as high as 0.5 mA/cm2 and 0.7 mA/cm2, which were recorded under direct and mediated electron transfer regimes, respectively. The experimental data were fitted to mathematical models showing that when the O2 is bioelectroreduced at high rotation speed of the electrode the heterogeneous electron transfer step is the rateliming stage. The electrochemical measurement hints a wider population of non-optimally wired laccases than previously reported for 5-8 nmsize Au nanoparticle-modified electrode, which could be due to a larger size of the AuNRs when compared to the laccases as well as their different crystal facets. © 2015 Elsevier B.V.This work was funded by the Seventh Framework Programme (BIOENERGY FP7-PEOPLE-2013-607793 project).Peer Reviewe

Enzymatic Logic Gates with Noise-Reducing Sigmoid Response

Biochemical computing is an emerging field of unconventional computing that attempts to process information with biomolecules and biological objects using digital logic. In this work we survey filtering in general, in biochemical computing, and summarize the experimental realization of an AND logic gate with sigmoid response in one of the inputs. The logic gate is realized with electrode-immobilized glucose-6-phosphate dehydrogenase enzyme that catalyzes a reaction corresponding to the Boolean AND functions. A kinetic model is also developed and used to evaluate the extent to which the performance of the experimentally realized logic gate is close to optimal.Comment: 14 pages, 2 figures, PD

Implementación de un centro de capacitación, asesoría y servicio contable-tributario para el micro y pequeño empresario de la ciudad de Daule, cantón Daule, provincia de Guayas, año 2012.

El presente trabajo investigativo, trata sobre la implementación de un centro de capacitación, asesoría y servicio contable-tributario para el micro y pequeño empresario de la ciudad de Daule cantón Daule, Provincia del Guayas el mismo que tiene como objetivo principal asesorar y brindar los servicios contables y tributarios rigiéndonos al cumplimiento de las leyes y normas, el producto es único en el mercado local, ya que la ciudadanía por falta de conocimiento no cumple con las obligaciones hacia la administración tributaria, nosotros brindamos estos conocimientos a través de capacitaciones, la empresa Reyes & Moya Asociados es la encargada de capacitar, asesorar y brindar los servicios contables y tributarios los mismos que están dirigidos hacia el micro y pequeño empresario de esta ciudad, a través de encuestas, realizadas directamente a la población económicamente activa de esta ciudad, la inversión se lo hará con el capital proporcionado por el banco de fomento, la propuesta está encaminada al conocimiento y cumplimiento  las normativas tributarias y tener un mejor administración para que estas le generen una mejor rentabilidad a los negocios, y por ende nos garantiza que podemos tener una rentabilidad acorde con la inversión efectuada

Lacasa de alto potencial redox funcional en sangre mediante evolución dirigida método de obtención y sus aplicaciones

La presente invención describe una lacasa de alto potencial redox obtenida mediante evolución molecular dirigida que es activa en condiciones electrofisiológicas, que resiste elevadas concentraciones de haluros, que tiene una actividad significativa a pHs neutros/alcalinos y que es activa en sangre y plasma humano. La presente invención se refiere a la secuencia aminoacídica de dicha lacasa, a la secuencia nucleotídica que codifica para dicha lacasa y células que permiten su obtención. La lacasa de la invención presenta aplicaciones en diversos sectores: nano-biotecnología, biomedicina, procesos de biorremediación, industria papelera y química fina.Peer reviewedConsejop Superior de Investigaciones CientíficasA1 Solicitud de patente con informe sobre el estado de la técnic

Lacasa de alto potencial redox funcional en sangre mediante evolución dirigida método de obtención y sus aplicaciones

La presente invención describe una lacasa de alto potencial redox obtenida mediante evolución molecular dirigida que es activa en condiciones electrofisiológicas, que resiste elevadas concentraciones de haluros, que tiene una actividad significativa a pHs neutros/alcalinos y que es activa en sangre y plasma humano. La presente invención se refiere a la secuencia aminoacídica de dicha lacasa, a la secuencia nucleotídica que codifica para dicha lacasa y células que permiten su obtención. La lacasa de la invención presenta aplicaciones en diversos sectores: nano-biotecnología, biomedicina, procesos de biorremediación, industria papelera y química fina.Peer reviewedConsejop Superior de Investigaciones CientíficasB1 Patente sin examen previ