812 research outputs found
Solitary wave collisions for Whitham-Boussinesq systems
This work concerns soliton-type numerical solutions for two
Whitham-Boussinesq-type models. Solitary waves are computed using an iterative
Newton-type and continuation methods with high accuracy. The method allow us to
compute solitary waves with large amplitude and speed close to the singular
limit. These solitary waves are set as initial data and overtaking collisions
are considered for both systems. We show that both system satisfy the geometric
Lax-categorization of two-soliton collision. Numerical evidences indicate that
one of the systems also admits an algebraic Lax-categorization based on the
ratio of the initial solitary wave amplitudes with a different range from the
one predicted by Lax. However, we show that such categorization is not possible
for the second system
Design and Fabrication of Flexible Copper Sensor Decorated with Bismuth Micro/Nanodentrites to Detect Lead and Cadmium in Noninvasive Samples of Sweat
The use of economic methods to design and fabricate flexible copper sensors decorated with bismuth micro/nanodentrites for the detection of lead and cadmium in sweat is demonstrated. The flexible copper sensors were constructed with simple and cost-effective materials; namely, flexible and adhesive conductive copper tape, adhesive label containing the design of a three-electrode electrochemical system, and nail polish or spray as a protective layer. The flexible copper device consisted of a working electrode decorated with bismuth micro/nanodentrites using an electrodeposition technique, a copper pseudo-reference and copper counter electrodes. Under optimal experimental conditions, the flexible sensing platform showed excellent performance toward the detection of lead and cadmium using differential pulse anodic stripping voltammetry (DPAdSV) in a wide linear range from 2.0 μM to 50 μM with acceptable reproducibility and repeatability, and limits of detection and quantification of 5.36 and 17.9 μM for Cd2+ ions and 0.76 μM and 2.5 for Pb2+ ions. Studies of addition and recovery in spiked artificial sweat sample were performed, with a recovery of 104.6%. The flexible copper device provides a great opportunity for application in wearable perspiration-based healthcare systems or portable sensors to detect toxic metals in biological samples
Taxonomic and non-taxonomic responses of benthic macroinvertebrates to metal toxicity in tropical reservoirs: The case of cantareira complex, São Paulo, Brazil
Benthic macroinvertebrates are organisms that are recognized as water quality bio-indicators. A wide variety of indices and metrics have been shown to respond to a variety of anthropogenic impacts, usually under a general condition of environmental impairment. The absence of a clear distinction in the relations between specific pollutants and biotic variables is very common and can lead to biased interpretation of biomonitoring. The aims of this research were to test taxonomic and non-taxonomic responses to specific environmental conditions instead to general conditions. For this purpose, we estimated the theoretical toxicity by comparing toxicity values published by EPA with metal concentrations in water and sediments. Then we tested the responses of biological variables to toxicity and other environmental conditions using the linear mixed effects models approach. We generated 32 models considering 24 different biological metrics and indices that were grouped in five levels. Taxonomic and abundance metrics were best predictor than functional or tolerance-based indexes. The strongest model was that which considered subfamily taxonomic resolution responding to Al_w and Cr_s.Fil: de Souza, Frederico Guilherme. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Cetra, Maurício. Universidade Federal do São Carlos; BrasilFil: Marchese Garello, Mercedes Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: López Dovál, Júlio César. Universidade de Sao Paulo; BrasilFil: Rosa, André H.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Pompêo, Marcelo L. M.. Universidade de Sao Paulo; BrasilFil: Moschini Carlos, Viviane. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi
14-Helical folding in a cyclobutane-containing β-tetrapeptide
The efficient synthesis of tetrapeptide 5 containing, in alternation, cyclobutane and β-alanine residues is described. NMR experiments both at low temperature in CDCl3 and at 298 K in DMSO-d6 solutions show the contribution of a strong hydrogen bond in the folded major conformation of 5. Temperature coefficients and diffusion times point out a hydrogen bond involving the NH proton from the cyclobutane residue 1 whereas NOEs manifest the high rigidity of the central fragment of the molecule and are compatible with a 14-membered macrocycle. Theoretical calculations predict a most stable folded conformation corresponding to a 14-helix stabilized by a hydrogen bond between NH10 in the first residue and OC25 in the third residue. This structure remains unaltered during the molecular dynamics simulation at 298 K in chloroform. All these results provide evidence for a 14-helical folding and reveal the ability of cis-2-aminocyclobutane carboxylic acid residues to promote folded conformations when incorporated into β-peptides.Fil: Izquierdo, Sandra. Universitat Autònoma de Barcelona; EspañaFil: Kogan, Marcelo Javier. Institut de Recerca Biomédica; EspañaFil: Parella, Teodor. Universitat Autònoma de Barcelona; EspañaFil: Moglioni, Albertina Gladys. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Branchadell, Vicenc. Universitat Autònoma de Barcelona; EspañaFil: Giralt, Ernest. Institut de Recerca Biomédica; EspañaFil: Ortuño, Rosa M.. Universitat Autònoma de Barcelona; Españ
LYTAG-driven purification strategies as a key to integrate and intensify the downstream processing of monoclonal antibodies
Monoclonal antibodies (mAbs) are currently the most important class of recombinant protein therapeutics in the biotechnological and biopharmaceutical industry with more than 250 mAbs currently undergoing clinical trials. High titer producing cultures and complex mixtures containing high cell densities, together with an increasing growing demand for highly pure mAbs is making recovery and purification processes hot targets for improvement and opens important technological challenges in mAbs manufacturing platforms.
This work explores the use of an affinity dual ligand based on a choline binding polypeptide tag (LYTAG) fused with the synthetic antibody Z domain (LYTAG-Z) as a tool to integrate and optimized the downstream processing of mAbs. Upon addition of this ligand to an animal cell culture broth, antibody-LYTAG-Z complexes are formed which can be easily captured and separated from host cell impurities by affinity partitioning in aqueous two-phase systems (ATPS) composed of polyethylene glycol –PEG, as PEG molecules have the ability to binding to the choline binding sites of LYTAG. Integration of clarification and primary mAbs recovery was successfully accomplished using a system composed of 6% PEG 3350 Da and 7% dextran 500,000 Da in which an extraction yield of 89% and a clarification higher than 95% were achieved. IgG-rich phases were further processed by chromatography, using three different strong anion exchange matrices charged with quaternary methyl amines (a choline analogue) – CIMmultus QA, HiTrap Q FF and gPore NW Q. A two-elution method was developed for the separation of the antibody-LYTAG-Z complexe, allowing simultaneous purification of the antibody and recovery of the ligand.
The process was successfully scale-up 10000 times allowing a global antibody recovery of 70% with a purity of 89% and enabling 100% cell removal
Variation of ultimate properties in extruded iPP-mesoporous silica nanocomposites by effect of iPP confinement within the mesostructures
Nanocomposites based on isotactic polypropylene (iPP) and mesoporous silica particles of either MCM-41 or SBA-15 were prepared by melt extrusion. The effect of the silica incorporated into an iPP matrix was firstly detected in the degradation behavior and in the rheological response of the resultant composites. Both were ascribed, in principle, to variations in the inclusion of iPP chains within these two mesostructures, with well different pore size. DSC experiments did not provide information on the existence of confinement in the iPP-MCM-41 materials, whereas a small endotherm, located at about 100 °C and attributed to the melting of confined crystallites, is clearly observed in the iPP-SBA-15 composites. Real-time variable-temperature Small Angle X-ray Scattering (SAXS) experiments with synchrotron radiation turned out to be crucial to finding the presence of iPP within MCM-41 pores. From these measurements, precise information was also deduced on the influence of the MCM-41 on iPP long spacing since overlapping does not occur between most probable iPP long spacing peak with the characteristic diffractions from the MCM-41 hexagonal nanostructure in comparison with existing superposition in SBA-15-based materials.Fil: Barranco García, Rosa. Instituto en Ciencia y Tecnología de Polímeros; EspañaFil: Gómez Elvira, José M.. Instituto en Ciencia y Tecnología de Polímeros; EspañaFil: Ressia, Jorge Aníbal. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Quinzani, Lidia Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Valles, Enrique Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Pérez, Ernesto. Instituto en Ciencia y Tecnología de Polímeros; EspañaFil: Cerrada, María L.. Instituto en Ciencia y Tecnología de Polímeros; Españ
Importancia de una correcta historia clínica
Introducción: La historia clínica es una herramienta fundamental en la práctica odontológica. Nos confiere una gran cantidad de datos imprescindibles. Objetivos: Explorar sobre la formulación de una correcta historia clínica en la consulta odontológica.Facultad de Odontologí
The influence of temperature and salinity on the impacts of lead in Mytilus galloprovincialis
Mussels, such as the marine bivalve Mytilus galloprovincialis are sentinels for marine pollution but they are also excellent bioindicators under laboratory conditions. For that, in this study we tested the modulation of biochemical responses under realistic concentrations of the toxic metal Lead (Pb) in water for 28 days under different conditions of salinity and temperature, including control condition (temperature 17 ± 1.0 °C and salinity 30 ± 1.0) as well as those within the range expected to occur due to climate change predictions (± 5 in salinity and + 4 °C in temperature). A comprehensive set of biomarkers was applied to search on modulation of biochemical responses in terms of energy metabolism, energy reserves, oxidative stress and damage occurrence in lipids, proteins as well as neurotoxicity signs. The application of an integrative Principal Coordinates Ordination (PCO) tool was successful and demonstrated that Pb caused an increase in the detoxification activity mainly evidenced by glutathione S-transferases and that the salinities 25 and 35 were, even in un-exposed mussels, responsible for cell damage seen as increased levels of lipid peroxidation (at salinity 25) and oxidised proteins (at salinity 35).publishe
Diferentes níveis de percepção da paisagem da lagoa da conceição (SC) através do SIG
Muitas cidades brasileiras vêm sofrendo um acelerado processo de modificação na paisagem, decorrente do crescente processo de urbanização. A Lagoa da Conceição, em Santa Catarina, insere-se neste contexto, sendo, portanto, a área escolhida para o presente trabalho. Este estudo busca a utilização de ferramentas que possibilitem leituras mais qualificadas da interação entre a paisagem natural e a paisagem construída. Para a elaboração do diagnóstico, diferentes escalas foram utilizadas no processo de percepção da paisagem. Na escala menor, que permite uma visão ampla da bacia hidrográfica da Lagoa da Conceição, foram identificadas as áreas a serem preservadas, as áreas apropriadas à ocupação urbana e as áreas de conflitos. A escala maior, que visualiza as áreas urbanizadas com maiores detalhes, possibilita a delimitação mais precisa e uma melhor compreensão dos conflitos apontados. Este detalhamento abrange a identificação dos agentes, dos usos e tipos de edificações mais presentes nos locais problemáticos. Entre os resultados obtidos citamos a divulgação das bases cartográficas atualizadas, a compreensão dos conflitos sociais e ambientais envolvendo o uso do solo e a elaboração de recomendações visando à futura ocupação da áreaThe landscapes of many brazilian cities have undergone an accelerated process of urbanization mainly due to poor planning. One such case is the Lagoa da Conceição, located in the Island of Santa Catarina, whose sudden growth was caused by the boom of tourism and, for that reason, chosen as the pilot area for this research. The study focuses on the search for tools that are able to provide a detailed interpretation of the interactions taking place between the natural and the man-made environments. For the spatial diagnosis, different scales of landscape perception were employed. On a general level it was possible to identify those areas that are more suitable for urban occupation, for natural preservation, and the areas of conflict over land use. On a detailed level, urbanized areas were analyzed enabling a better zoning and a clearer insight of conflicting areas. This detailing involves the identification of urban agents, and of the dominant construction types and uses in problematic areas. Among the results obtained are the spreading of updated cartographical bases, the understanding of the social and environmental conflicts revolving around land use, and the elaboration of recommendations regarding the future occupation of the are
Manganese Defective Clustering: Influence on the Spectroscopic Features of Ceria-Based Nanomaterials
The influence of manganese modification on the spectroscopic features of manganese-doped CeO2 systems synthesized by the microwave-assisted hydrothermal route and their correlation with the presence of O defective structures were verified, focusing on their interaction with poisonous atmospheres. Raman and electron paramagnetic resonance studies confirmed the presence of defective clusters formed by dipoles and/or quadrupoles. The number of paramagnetic species was found to be inversely proportional to the doping concentration, resulting in an increase in the Mn2+ signal, likely due to the reduction of Mn3+ species after the interaction with CO. X-ray photoelectron spectroscopy data showed the pure system with 33% of its cerium species in the Ce3+ configuration, with an abrupt decrease to 19%, after the first modification with Mn, suggesting that 14% of the Ce3+ species are donating one electron to the Mn2+ ions, thus becoming nonparamagnetic Ce4+ species. On the contrary, 58% of the manganese species remain in the Mn2+ configuration with five unpaired electrons, corroborating the paramagnetic feature of the samples seen in the electron paramagnetic resonance study
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