Fabio Leite | UFSCar - Federal University of São Carlos (original) (raw)

Journal Articles by Fabio Leite

A aplicação de agroquímicos em plantações acarreta em danos ao meio ambiente, devido ao seu alto ... more A aplicação de agroquímicos em plantações acarreta em danos ao meio ambiente, devido ao seu alto risco biológico
(acúmulo e disseminação no bioma). Neste contexto, novos métodos de sensoriamento podem ser destacados como objeto
de pesquisa no monitoramento ambiental, e.g., o desenvolvimento de sensores aliado à nanotecnologia podem fornecer
ferramentas promissoras, eficientes e seletivas. Neste trabalho, estudou-se parâmetros e metodologias de interação
específica entre um anticorpo (anti-atrazina) e um herbicida (atrazina) utilizando a técnica de espectroscopia de força
atômica, uma ferramenta da microscopia de força atômica. Tais estudos forneceram resultados preliminares promissores
para o desenvolvimento de um nanobiossensor específico para detecção de herbicidas, em especial, a atrazina. Foram
comparados substratos funcionalizados com diferentes substâncias (atrazina, imazaquim, metsulfuron-metil e água) para
avaliação da interação específica entre atrazina versus anti-atrazina (complexo antígeno-anticorpo). Os dados obtidos
comprovaram a eficiência do nanodispositivo, sendo que a interação observada entre o herbicida atrazina e seu respectivo
anticorpo foi expressiva, comparada com àquelas apresentadas por outros herbicidas.

Neste trabalho esta sendo proposto a construcao de uma balanca com materiais de baixo custo pa... more Neste trabalho esta sendo proposto a construcao de uma balanca com materiais de baixo custo para determinacao da tensao super cial de lquidos. A con abilidade das medidas foi comprovada comparando os resultados
obtidos com aqueles apresentados na literatura para lquidos simples, e empregando o metodo da ascensao capilar
para o caso de outros lquidos. Por este metodo, os erros sistematicos dos resultados obtidos foram reduzidos
consideravelmente. O princpio de funcionamento do dispositivo consiste na medida da forca necessaria para
desprender uma l^amina de vidro parcialmente imersa em um lquido. Os valores da tens~ao super cial sao calculados
com base nos conceitos de momento de forcas, e considera as interacoes intermoleculares entre a lamina e
a superfcie do lquido.

A microcantilever sensor is presented. Functionalization of the cantilever with a polyaniline (PA... more A microcantilever sensor is presented. Functionalization of the cantilever with a polyaniline (PANI) sensitive
layer and its use as a humidity sensor were investigated. Polyaniline was produced by interfacial
synthesis and the sensitive layer was deposited on the microcantilever surface by the spin-coating
method. The microcantilever deflection at various levels of relative humidity (RH) was read by means
of the optical lever of an atomic force microscope (AFM Veeco Dimension V). A range of RH from 20%
to 70% was introduced into the AFM chamber by mixing streams of dry and wet nitrogen. The sensitivity
and reversibility of the sensors were assessed at various RH and temperatures (10, 20 and 30 C). A large
deflection was observed in the coated microcantilever sensors, with faster response time at 10 C and better
sensitivity and reversibility at 30 C. These results demonstrate that the spin-coated microcantilever
can be used as a sensor to detect relative humidity at various different temperatures

In the work presented in this article surface chemical modifi cation was applied to ramie cellulo... more In the work presented in this article surface chemical modifi cation was applied to ramie cellulose nanocrystals
by grafting organic acid chlorides presenting different lengths of the aliphatic chain. The objective of this
surface chemical treatment was to enhance the nonpolar nature of the grafted nanocrystals and improve their
dispersibility in a nonpolar polymeric matrix. The occurrence of the chemical modifi cation was evaluated
by Fourier transform infrared (FTIR) spectroscopy, the degree of crystallinity by X-ray diffraction, and
the morphology by scanning electron microscopy with fi eld emission gun (FEG-SEM) and atomic force
microscopy (AFM). The morphology and crystallinity provided by different experimental methods were
carefully compared.

Não há conflitos de interesse. Todos os direitos editoriais adquiridos. Artigo recebido em: 02 de... more Não há conflitos de interesse. Todos os direitos editoriais adquiridos. Artigo recebido em: 02 de Agosto de 2014. Artigo aceito em: 12 de Outubro de 2014. RESUMO INTRODUÇÃO: A esclerose múltipla é u m a d o e n ç a a u t o i m u n e d e c a r á t e r progressivo no SNC (Sistema Nervoso C e n t r a l ) . O m o d e l o d e E A E (Encefalomielite Autoimune Experimental) é capaz de reproduzir a patogenicidade da esclerose múltipla associada à resposta i m u n i t á r i a . O s l i n f ó c i t o s T encefalitogênicos têm papel importante na esclerose múltipla e tem-se tentado modular essas células através de estratégias terapêuticas. A pregabalina é um fármaco análogo ao ácido gama-aminobutírico (GABA) que atua como anticonvulsivante, o qual reduz a liberação de noradrenalina e glutamato, bem como tem a capacidade de modular a transmissão sináptica excitatória e promover efeitos antiapoptóticos e antiinflamatórios. OBJETIVOS: Analisar morfologicamente, in vitro, a neuroproteção promovida pela pregabalina em culturas de células neuronais com meio condicionado contendo linfócitos T encefalitogênicos. MÉTODOS: Camundongos C57BL/6 fêmeas de seis semanas de idade foram induzidos para EAE. Decorridos dez dias da Pregabalina protege neurônios da ação pró-inflamatória de linfócitos T encefalitogênicos.

tA stochastic simulation of adsorption processes was developed to simulate the coverage of an ato... more tA stochastic simulation of adsorption processes was developed to simulate the coverage of an atomic forcemicroscope (AFM) tip with enzymes represented as rigid polyhedrons. From geometric considerationsof the enzyme structure and AFM tip, we could estimate the average number of active sites available tointeract with substrate molecules in the bulk. The procedure was exploited to determine the interactionforce between acetyl-CoA carboxylase enzyme (ACC enzyme) and its substrate diclofop, for which steeredmolecular dynamics (SMD) was used. The theoretical force of (1.6 ± 0.5) nN per enzyme led to a total forcein remarkable agreement with the experimentally measured force with AFM, thus demonstrating theusefulness of the procedure proposed here to assist in the interpretation of nanobiosensors experiments

Paclitaxel (Taxol®), is a drug used to treat ovarian, breast, lung and bladder cancer. However, t... more Paclitaxel (Taxol®), is a drug used to treat ovarian, breast, lung and bladder cancer. However, the low solubility of this drug in water is a major limitation in its clinical use. One strategy to overcome this limitation would be to encapsulate paclitaxel in polymeric microspheres that are biocompatible and can be used as drug carriers. The aim of this study was to use the bioresorbable, biocompatible copolymer poly-L-co-D,L-lactic acid (PLDLA) in the 70:30 rate to produce and characterize
microspheres containing paclitaxel. The simple emulsion technique was used to obtain spherical microspheres that were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The average size of PLDLA microspheres without and with paclitaxel was 10.3 ± 1.7 μm
and 12.7 ± 1.3 μm, respectively, as determined by laser light scattering (LLS). Differential scanning calorimetry (DSC) showed that pure paclitaxel had an endothermic peak corresponding to a meltingpoint of 220 °C, which indicated its crystalline nature. The same peak was observed in a physical mixture of PLDLA + paclitaxel in which both components were present in the same proportions used to prepare the microspheres . In contrast, this peak was not observed for the drug, indicating that paclitaxel
did not crystallize in PLDLA microspheres. Differential scanning calorimetry (DSC) indicated that paclitaxel was homogeneously dispersed in the PLDLA microspheres, the incorporation of paclitaxel into the microspheres did not alter the thermal properties of PLDLA. The Fourier transform infrared spectroscopy (FTIR) analysis seems to indicate the absence of chemical interaction between polymer and drugs in microspheres and the presence of drugs as a molecular dispersion in the polymer matrix. The efficiency of paclitaxel encapsulation in PLDLA microspheres was 98.0 ± 0.3%, as assessed by high performance liquid chromatography (HPLC). A kinetic study of drug release in vitro using HPLC showed an initial burst release followed by a slower release characteristic of large diameter distribution systems. PLDLA microspheres released 90 ± 4% of the drug over a 30-day period. These
findings indicate that PLDLA microspheres are promising carriers for paclitaxel, with a potential for future applications in drug delivery systems.

The strong effect of doping on the sensitivity of the sensor was attributed to an increased adsor... more The strong effect of doping on the sensitivity of the sensor was attributed to an increased adsorption of water molecules dissociated at imine nitrogen centers, which improves the performance of the coated microcantilever sensor. Moreover, microcantilever sensors coated with a sensitive layer provided good results in several cycles of exposure to RH (%). SCANNING 36:311-316, 2014.

The development of sensitive methodologies for detecting agrochemicals has become important in re... more The development of sensitive methodologies for detecting agrochemicals has become important in recent years due to the increasingly indiscriminate use of these substances. In this context, nanosensors based on atomic force microscopy (AFM) tips are useful because they provide higher sensitivity with operation at the nanometer scale. In this paper we exploit specific interactions between AFM tips functionalized with the enzyme acetolactate synthase (ALS) to detect the ALSinhibitor herbicides metsulfuron-methyl and imazaquin. Using atomic force spectroscopy (AFS) we could measure the adhesion force between tip and substrate, which was considerably higher when the ALS-functionalized tip (nanobiosensor) was employed. The increase was approximately 250% and 160% for metsulfuron-methyl and imazaquin, respectively, in comparison to unfunctionalized probes. We estimated the specific enzyme-herbicide force by assuming that the measured force comprises an adhesion force according to the Johnson-Kendall-Roberts (JKR) model, the capillary force and the specific force. We show that the specific, biorecognition force plays a crucial role in the higher sensitivity of the nanobiosensor, thus opening the way for the design of similarly engineered tips for detecting herbicides and other analytes.

Highly sensitive and selective functional nanobiobreaksensors are being developed because they ha... more Highly sensitive and selective functional nanobiobreaksensors are being developed because they have significant applications in the sustenance and conservation of natural resources and can be used in projects to identify degraded and contaminated areas (of both soil and water) and as environmental quality indicators. In the present study, a nanobiosensor was developed based on using theoretical models (molecular docking and molecular dynamics simulations) based on biomimicry of the action mechanism of herbicides in plants coupled with atomic force microscopy (AFM) tools. The herbicide molecules were detected at very low concentrations using a unique sensor construction: the AFM probes and the substrate were chemically functionalized to favor covalent bonding and promote molecular flexibility, as well as to achieve reproducible and accurate results. Computational methods were used to determine the binding energies associated with the enzyme-herbicide interactions, which were compared with experimental results for adhesion forces. The theoretical results showed that the diclofop herbicide could be assembled and attached onto the mica substrate surface and the ACCase enzyme on the AFM probe without damaging the diclofop molecule. The experimental results showed that using a specific agrochemical target molecule was more efficient than using other nonspecific agrochemicals. On average, there was a 90% difference between the values of specific recognition (diclofop) and nonspecific recognition (imazaquin, metsulfuron, and glyphosate). This result validated the selectivity and specificity of the nanobiosensor. The first evidence of diclofop detection by the AFM probe sensors has been presented in this paper.

This paper describes a silicon cantilever sensor coated with a conducting polymer layer. The mech... more This paper describes a silicon cantilever sensor coated with a conducting polymer layer. The mechanical response (deflection) of the bimaterial (the coated microcantilever) was investigated under the influence of several volatile compounds-methanol, ethanol, acetone, propanol, dichloroethane, toluene and benzene. The variations in the deflection of the coated and uncoated microcantilevers when exposed to volatile organic compounds were evaluated, and the results indicated that the highest sensitivity was obtained with the coated microcantilever and methanol. The uncoated microcantilever was not sensitive to the volatile organic compounds. An increase in the concentration of the volatile organic compound resulted in higher deflections of the microcantilever sensor. The sensor responses were reversible, sensible, rapid and proportional to the volatile concentration.

A microcantilever sensor is presented. Functionalization of the cantilever with a polyaniline (PA... more A microcantilever sensor is presented. Functionalization of the cantilever with a polyaniline (PANI) sensitive layer and its use as a humidity sensor were investigated. Polyaniline was produced by interfacial synthesis and the sensitive layer was deposited on the microcantilever surface by the spin-coating method. The microcantilever deflection at various levels of relative humidity (RH) was read by means of the optical lever of an atomic force microscope (AFM Veeco Dimension V). A range of RH from 20% to 70% was introduced into the AFM chamber by mixing streams of dry and wet nitrogen. The sensitivity and reversibility of the sensors were assessed at various RH and temperatures (10, 20 and 30°C). A large deflection was observed in the coated microcantilever sensors, with faster response time at 10°C and better sensitivity and reversibility at 30°C. These results demonstrate that the spin-coated microcantilever can be used as a sensor to detect relative humidity at various different temperatures.

Bio-inspired materials designed for mimicking nature has gained attention in the last years, owin... more Bio-inspired materials designed for mimicking nature has gained attention in the last years, owing to their appealing properties, such as adhesive and self-cleaning properties. However, studies reporting bio-inspired sensors able to detect minimal amounts of pheromones are still scarce. Here we report on the functionalization of AFM cantilever with polyaniline (PANI), which was used as a sensor to detect pheromone 2-heptanone. This hormone is very significant for honey bees, which release it as a repellent scent marking to avoid enemies and other bees. The functionalization of the sensor was achieved by depositing a thin film of PANI in the emeraldine state on the cantilever through spin-coating. Infrared spectroscopy showed that the 2-heptanone was adsorbed by PANI film deposited on cantilever surface. The linear response of the coated cantilever sensor regarding 2-heptanone concentration for distinct temperatures was evaluated, as well as its mechanical behavior, hysteresis and storage time. The approach proposed here to functionalize AFM cantilever with PANI film to detect 2-heptanone showed a potential methodology for designing sensors able to detect minimal amounts of pheromones and natural compounds.

The immobilization of enzymes on atomic force microscope tip (AFM tip) surface is a crucial step ... more The immobilization of enzymes on atomic force microscope tip (AFM tip) surface is a crucial step in the development of nanobiosensors to be used in detection process. In this work, an atomistic modeling of the attachment of the acetyl coenzyme A carboxylase (ACC enzyme) on a functionalized AFM tip surface is proposed. Using electrostatic considerations, suitable enzyme-surface orientations with the active sites of the ACC enzyme available for interactions with bulk molecules were found. A 50 ns molecular dynamics trajectory in aqueous solution was obtained and surface contact area, hydrogen bonding and protein stability were analyzed. The enzyme-surface model proposed here with minor adjustment can be applied to study antigen-antibody interactions as well as enzyme immobilization on silica for chromatography applications.

Atomic force spectroscopy, a technique derived from Atomic Force Microscopy (AFM), allowed us to ... more Atomic force spectroscopy, a technique derived from Atomic Force Microscopy (AFM), allowed us to distinguish nonspecific and specific interactions between the acetolactate synthase enzyme (ALS) and anti-atrazine antibody biomolecules and the herbicides imazaquin, metsulfuron-methyl and atrazine. The presence of specific interactions increased the adhesion force (F adh ) between the AFM tip and the herbicides, which made the modified tip a powerful biosensor. Increases of approximately 132% and 145% in the F adh values were observed when a tip functionalized with ALS was used to detect imazaquin and metsulfuron-methyl, respectively. The presence of specific interactions between the atrazine and the anti-atrazine antibody also caused an increase in the F adh values (approximately 175%) compared to those observed when using an unfunctionalized tip. The molecular modeling results obtained with the ALS enzyme suggest that the orientation of the biomolecule on the tip surface could be suitable for allowing interaction with the herbicides imazaquin and metsulfuron-methyl.

The use of agrochemicals has increased considerably in recent years, and consequently, there has ... more The use of agrochemicals has increased considerably in recent years, and consequently, there has been increased exposure of ecosystems and human populations to these highly toxic compounds. The study and development of methodologies to detect these substances with greater sensitivity has become extremely relevant. This article describes, for the first time, the use of atomic force spectroscopy (AFS) in the detection of enzyme-inhibiting herbicides. A nanobiosensor based on an atomic force microscopy (AFM) tip functionalised with the acetolactate synthase (ALS) enzyme was developed and characterised. The herbicide metsulfuron-methyl, an ALS inhibitor, was successfully detected through the acquisition of force curves using this biosensor. The adhesion force values were considerably higher when the biosensor was used. An increase of ~250% was achieved relative to the adhesion force using an unfunctionalised AFM tip. This considerable increase was the result of a specific interaction between the enzyme and the herbicide, which was primarily responsible for the efficiency of the nanobiosensor. These results indicate that this methodology is promising for the detection of herbicides, pesticides, and other environmental contaminants.

Scanning, Jan 1, 2008

Dynamic atomic force spectroscopy (DAFS) or "damped oscillation" method consists of a vibrating m... more Dynamic atomic force spectroscopy (DAFS) or "damped oscillation" method consists of a vibrating microcantilever after pull-off force, with a nanoscale tip that interacts with a sample surface via short-and long-range intermolecular forces. When the motion of an oscillator is reduced by an external force, the oscillator and its motion are said to be damped. This work presents results of the characterization of physicochemical properties of sisal fibers using DAFS technique. To evaluate to adhesion and surface energy were used as samples inorganic materials (mica and quartz) as well as organic materials as sisal fibers. Delignified, benzylated and in natura sisal fiber were characterized by atomic force microscopy (AFM), force spectroscopy (AFS) and DAFS. A very large variation was observed among the DAFS measures as can bee seen in the Fig. 1. Understanding these phenomena can offer deep insight into physics of DAFS and provide exciting possibilities for achieving better materials physicochemical information. The experiments were carried out at environmental condition using the silicon cantilever with rectangular shaped and spring constant of 0.03 N m -1 . Observe one that the adhesion force and surface energy changes considerably the oscillation amplitude, the frequency delay and curve profile. The method open new possibilities to evaluate the condition of the cantilever and could supply information about the environment where the experiment are made. With this technique can one obtain viscosity values of gases and liquids, which the liquid exerts a damping force that is proportional in magnitude to the withdrawal velocity of the tip.

A microcantilever sensor is presented. Functionalization of the cantilever with a polyaniline (PA... more A microcantilever sensor is presented. Functionalization of the cantilever with a polyaniline (PANI) sensitive layer and its use as a humidity sensor were investigated. Polyaniline was produced by interfacial synthesis and the sensitive layer was deposited on the microcantilever surface by the spin-coating method. The microcantilever deflection at various levels of relative humidity (RH) was read by means of the optical lever of an atomic force microscope (AFM Veeco Dimension V). A range of RH from 20% to 70% was introduced into the AFM chamber by mixing streams of dry and wet nitrogen. The sensitivity and reversibility of the sensors were assessed at various RH and temperatures (10, 20 and 30°C). A large deflection was observed in the coated microcantilever sensors, with faster response time at 10°C and better sensitivity and reversibility at 30°C. These results demonstrate that the spin-coated microcantilever can be used as a sensor to detect relative humidity at various different temperatures.

Scanning, Jan 1, 2008

Atomic Force Microscopy in Adhesion Studies, 2005

This review article describes the fundamental principles of atomic force spectroscopy (AFS) and h... more This review article describes the fundamental principles of atomic force spectroscopy (AFS) and how this technique became a useful tool to investigate adhesion forces. AFS is a technique derived from atomic force microscopy (AFM) and can determine, at every location of the sample surface, the dependence of the interaction on the probe-sample distance. AFS provides valuable information, at the nano-scale, such as, for example: (i) how the magnitude of the adhesion force depends on long-and short-range interactions and (ii) the tip-sample contact area. An overview about the theory and experiments with local force spectroscopy, force imaging spectroscopy, chemical force microscopy and colloidal probe technique is presented. The many applications of the AFS technique for probing surface interactions open up new possibilities to evaluate adhesion, an important characteristic of materials.

Atomic Force Microscopy in Adhesion Studies, 2005

Modern Research and Educational Topics in Microscopy, 2007

Atomic force microscopy (AFM) has been useful to investigate materials performance, processes, ph... more Atomic force microscopy (AFM) has been useful to investigate materials performance, processes, physical and surface properties at the nanometer scale. In addition to the standard AFM, which measures surface topography, many accessories have been developed to obtain specific additional information. In this chapter, we shall concentrate on atomic force spectroscopy (AFS), which derived from AFM and is used to measure surface forces through force curves. The latter curves have become an important tool to study materials properties, such as elasticity, surface charge densities and wettability. With AFS one probes interactions at the nanometer scale, especially van der Waals interactions and double-layer forces. A brief theoretical background is included, and we comment on the large variety of measurements involving AFS.

Global Optimization: Focus on Simulated Annealing, 2008

Microscopy: Science, Technology, Applications and Education, 2010

The atomic force microscopy (AFM) is a powerful for single-molecule force experiment that can cha... more The atomic force microscopy (AFM) is a powerful for single-molecule force experiment that can characterize physical and chemical properties of biological and polymeric matter at the nanometer scale. However, it does not reveal the molecular mechanisms behind the binding of ligands and conformational changes in biomolecules in atomic time scale. This information can only be addressed by molecular dynamics (DM) simulation, which simulates the AFM experiments through methodology called Steered Molecular Dynamics (SMD). The AFM simulation is usually obtained by integrating the mean force from an ensemble of configurations resulted from a molecular mechanics calculation. In this chapter, we shall concentrate on simulation of the atomic force spectroscopy (AFS), which procedure consist in perform a constant velocity molecular dynamics simulation, recording force and position at each time point, to reproduce and predict the atomic force curves. The AFM simulation showed to be very useful to provide qualitative and quantitative information about ligand binding pathways in enzymes and the mechanical properties of biological and synthetic polymers.

Nanostructured Conductive Polymers, 2010

Scanning Probe Microscopy in Nanoscience and Nanotechnology (NanoScience and Technology), 2010

The series NanoScience and Technology is focused on the fascinating nano-world, mesoscopic physic... more The series NanoScience and Technology is focused on the fascinating nano-world, mesoscopic physics, analysis with atomic resolution, nano and quantum-effect devices, nanomechanics and atomic-scale processes. All the basic aspects and technology-oriented developments in this emerging discipline are covered by comprehensive and timely books. The series constitutes a survey of the relevant special topics, which are presented by leading experts in the f ield. These books will appeal to researchers, engineers, and advanced students.

Current microscopy contributions to advances in science and technology, 2012

Nowadays, there are major concerns about global environmental problems, resulting from high popul... more Nowadays, there are major concerns about global environmental problems, resulting from high population growth and consequent increase in industrial production and contaminants generation. The high global demand for food, for example, is causing the excessive use of pesticides and fertilizers, used to increase and ensure the quality of production. However, most of these chemicals accumulate, causing soil and groundwater contamination. Within this context, the development of new methods, with greater sensitivity and selectivity, in order to detect these compounds even at extremely low concentrations, is essential for the prospection of contaminated areas. Regarding the sensitivity, the employment of nanosensors has proved to be extremely efficient for pesticide detection. When combined with biomolecules, those nanosystems become selective being able to detect only one type or class of pesticides. This chapter will present potential methods for agrochemicals detection, based on a combination of nanobiosensors with different operating modes of Atomic Force Microscopy, in particular, Chemical Force Microscopy.

Scanning Probe Microscopy in Nanoscience and Nanotechnology, Jan 2012

Requeiro à Mesa, lido em plenário, nos termos regimentais, que seja enviada a presente MOÇÃO DE A... more Requeiro à Mesa, lido em plenário, nos termos regimentais, que seja enviada a presente MOÇÃO DE APLAUSO aos Professores e Alunos do Ensino Fundamental, Participantes

Dois as trô no mos, um ame ri ca no e um alemão, obser va ram pe la pri mei ra vez a mis te rio s... more Dois as trô no mos, um ame ri ca no e um alemão, obser va ram pe la pri mei ra vez a mis te rio sa de sin te gração de um as te roi de, uma des co berta pu bli ca da na re vis ta Astrophy si cal Jour nal Let ters.

Ao criar o que foi descrito como um "supercérebro" de mentes co-nectadas, o cientista paulista Mi... more Ao criar o que foi descrito como um "supercérebro" de mentes co-nectadas, o cientista paulista Mi-guel Nicolelis afirmou na última quinta-feira que conseguiu fazer com que um rato ajudasse outro companheiro roedor, embora os animais estivessem em continen-tes diferentes, conectados através de eletrodos cerebrais. Com eletrodos instalados em seu córtex, um rato em um insti-tuto de pesquisa da cidade de Natal enviou sinais via internet para outro roedor de um laboratório de uma universidade em Durham, na Carolina do Norte, ajudando o se-gundo animal a obter uma recom-pensa. A façanha abre a perspecti-va de conectar os cérebros entre os animais para criar um "compu-tador biológico", afirmou o neuro-biólogo. Isso também é uma ferramen-ta na missão de capacitar pacien-tes que sofrem de paralisia ou de síndrome de encarceramento, ex-plicou. "Estabelecemos uma ligação funcional entre dois cérebros. Criamos um supercérebro que compreende dois cérebros", disse Nicolelis. Com sua pesquisa publicada na revista Scientific Reports, a equipe de Nicolelis forneceu um treinamento básico para ratos com sede, que precisaram reco-nhecer luzes e operar uma alavan-ca para receber uma recompensa de água. Eles, então, implantaram ele-trodos ultrafinos nos cérebros dos ratos, que estavam ligados por um cabo a um computador. Em um tanque de vidro em Natal , o primeiro rato foi o "codifica-dor", e seu cérebro enviava um flu-xo de impulsos elétricos conforme ele descobria os truques para ob-ter a recompensa. Os impulsos fo-ram enviados em tempo real para o córtex do segundo rato, o "deco-dificador", que estava diante da mesma situação em um tanque na Carolina do Norte. Com estas sugestões de seu ca-marada, o rato decodificador des-cobriu rapidamente como obter a recompensa. "Os dois animais co-laboraram para resolver uma tare-fa juntos", ressaltou o pesquisa-dor. O que o segundo rato recebeu não foram pensamentos, nem mesmo imagens, disse Nicolelis. Quando o rato codificador con-seguiu cumprir várias tarefas, os picos dos sinais em seu cérebro fo-ram transcritos para um padrão intrigante de sinais eletrônicos, que foram recebidos pelo rato de-codificador. Depois que o rato des-cobriu a utilidade destes padrões, eles se incorporaram ao seu pro-cessamento visual e tátil. "O se-gundo rato aprende a reconhecer um padrão, um padrão estatístico, que descreve uma decisão tomada pelo primeiro rato. Ele está crian-do uma associação daquele padrão com uma decisão", expli-cou o pesquisador brasileiro. "Ele pode estar sentindo um pequeno estímulo tátil, mas é algo que não sabemos como descrever porque não podemos questionar a cobaia". "A ligação sugere que po-deríamos criar uma rede cerebral, formada de cérebros juntos, todos interagindo", afirmou o cientista, apressando-se em ressaltar que este será um experimento que será conduzido apenas em animais de laboratório, e não em seres huma-nos. "Se você conectar cérebros de vários animais, cérebros de ratos ou cérebros de primatas, você provavelmente poderia criar um computador biológico que é uma máquina não-Turing, uma máqui-na que não trabalhe de acordo com o projeto de Turing de todos os computadores digitais que co-nhecemos. Seria heurístico, não usaria um algoritmo e utilizaria um processo decisório probabilís-tico baseado em um hardware biológico". Ainda não está claro como o animal decodificador incorpora os sinais do codificador em seu espaço mental, um fenômeno co-nhecido como plasticidade corti-cal. "Nós basicamente mostra-mos que o animal decodificador pode incorporar outro corpo co-mo extensão do mapa que o animal tem em sua próprio

A cidades 8 SOROCABA • QUINTA-FEIRA • 20 DE AGOSTO DE 2015

O diagnóstico precoce de certos tipos de câncer ou de enfermidades do sistema nervoso, como escle... more O diagnóstico
precoce de certos tipos de câncer ou de enfermidades do sistema nervoso, como esclerose
múltipla ou neuromielite óptica, poderá ser facilitado em breve com o emprego de novo dispositivo de detecção: um sensor de dimensão nanométrica capaz de identificar os
biomarcadores dessas condições patológicas.

Divulgação 0 NOTICIAS / EDUCAÇÃO / 18 de Dezembro de 2011, Domingo, às 14h25 Recomendar 0 Tweet 0... more Divulgação 0 NOTICIAS / EDUCAÇÃO / 18 de Dezembro de 2011, Domingo, às 14h25 Recomendar 0 Tweet 0 Contato com a Redação Sugerir uma reportagem Enviar uma foto Reclamação ÁREA DO LEITOR Jornal Ipanema Curtir 7.429 pessoas curtiram Jornal Ipanema.

Direitos desta edição adquiridos pela Paco Editorial. Nenhuma parte desta obra pode ser apropriad... more Direitos desta edição adquiridos pela Paco Editorial. Nenhuma parte desta obra pode ser apropriada e estocada em sistema de banco de dados ou processo similar, em qualquer forma ou meio, seja eletrônico, de fotocópia, gravação, etc., sem a permissão da editora e/ou autor.

Caro leitor, este livro foi redigido de forma especial e suas palavras ganharam vida! Não tenho v... more Caro leitor, este livro foi redigido de forma especial e suas palavras ganharam vida! Não tenho vontade de eternizá-lo, minha ambição está restrita às suas emoções, mas o aceite como um presente e deixe-o jazer em sua cômoda. Tenho a súbita impressão de que este livro manifesta o desejo de liberdade, de poder voar e fantasiar – acho que ele deseja ter
o fim que você lhe destinar. Enfim, qualquer que seja a sina deste livro, jamais esqueça sua mensagem, a história límpida e serena contada na forma de prosas poéticas, revelada de forma reflexiva e misteriosa. Esta obra, de caráter essencialmente autobiográfica, retrata momentos profundos desenhados em palavras, cravados em píncaros. São revelações que perpassam toda minha vida, uma jornada nada plácida. Relembro o
primeiro beijo, o primeiro encontro com a ciência, o primeiro amor, o último adeus. As poesias retratam três épocas distintas de minha vida: a primeira fase, entre os anos de 1988 e 1996; a segunda fase, entre os anos de 1997 e 2011; e a terceira fase, após o ano de 2012.

O Encontro Regional de Futuros Cientistas (ERFC) é um evento transdisciplinar que tem como foco p... more O Encontro Regional de Futuros Cientistas (ERFC) é um
evento transdisciplinar que tem como foco principal agregar
valores, disseminar conhecimento e divulgar os trabalhos
desenvolvidos nas escolas credenciadas ao Programa Futuro
Cientista® (PFC). A ideia é despertar o aprendizado pela
descoberta por intermédio de projetos científicos e tecnológicos.
Os “futuros cientistas” têm a oportunidade de mostrar
sua criatividade e inventividade diante de um público
curioso e atento as inovações. Os professores, coordenadores
locais, nucleadores, empresas e algumas figuras políticas
também realizam um papel importante na formação do futuro
cientista, seja no incentivo de uma bolsa de estudos, uma
viagem acadêmica ou “adoção” científica. O evento é organizado
pelos professores e alunos da Universidade Federal de
São Carlos (UFSCar), campus Sorocaba, com parceria direta
do CNPq1, MEC (PROEXT)2, Gerdau3, CCBEU4, UNISO,5
Colégio Objetivo,6 Prefeitura Municipal de Cesário Lange7 e
Pró-Reitoria de Extensão8.

O primeiro volume da coleção aborda os principais conceitos e fundamentos da nanociência, enfati... more O primeiro volume da coleção aborda os principais conceitos e fundamentos da nanociência,
enfatizando as características e propriedades de inúmeras nanoestruturas.
Esta publicação visa a familiarizar o leitor com as diversas aplicações de nanoestruturas.
O texto é direto, rico em informações; profundo, mas de fácil compreensão.
Alguns capítulos foram redigidos de forma mais técnica e científica possível, com
abrangência e profundidade necessárias para a leitura de um profissional exigente.
Por outro lado, alguns capítulos são mais introdutórios, explorando potencialidades
do tema. Para permitir uma leitura coerente os capítulos foram agrupados por temas
similares, conferindo fluidez e dinâmica na aprendizagem do leitor.

O terceiro volume da coleção Nanociência e Nanotecnologia: Princípios e Aplicações aborda as pri... more O terceiro volume da coleção Nanociência e Nanotecnologia: Princípios e Aplicações
aborda as principais técnicas de caracterização de nanomateriais e nanoestruturas.
Os temas apresentados neste volume ocupam um espaço apreciável nos programas
de pós-graduação do Brasil. Portanto, acreditamos que o volume possa ser útil a
docentes (orientadores) e alunos (orientados) de áreas básicas da ciência, além daqueles
que não estudam diretamente nanociência e nanotecnologia. Os capítulos
também servirão para consulta tanto para os iniciantes em pesquisa científica quanto
para um público não especializado. Os textos foram dedicados aos aspectos básicos
das técnicas de caracterização nas suas distintas abordagens, facilitando o acesso às
noções gerais e específicas de tais instrumentos. Os avanços significativos e os fundamentos
matemáticos necessários para entendimento das técnicas também foram
explorados.

O segundo volume da coleção Nanociência e Nanotecnologia: Princípios e Aplicações aborda as prin... more O segundo volume da coleção Nanociência e Nanotecnologia: Princípios e Aplicações
aborda as principais aplicações do nanomundo, integrando grandes áreas da ciência
de forma multidisciplinar. O entendimento, controle e a exploração de materiais e
sistemas em nível molecular fornecem propriedades e fenômenos físicos, químicos
e biológicos significativamente novos. O objetivo principal dos nanocientistas é explorar
estas novas propriedades para futuras aplicações tecnológicas, compreendendo
os fenômenos da natureza e suas respectivas implicações para o bem-estar humano
e no desenvolvimento da nossa civilização. Nos últimos anos, devido à grande variabilidade
de demandas na sociedade, novas áreas de pesquisa surgiram e os efeitos
sociais destes novos campos de exploração podem ser mensurados por intermédio de
resultados de impacto em áreas como tecnologia da informação, medicina e saúde,
meio ambiente e energia, nanoeletrônica e nanometrologia. Tais avanços e impactos
foram inseridos nos capítulos deste livro, particularmente nas áreas de eletrônica,
energia, materiais, meio ambiente e saúde.

Layer-by-layer (LbL) films of poly(o-ethoxyaniline) (POEA), chitosan and chitosan-poly(methacryli... more Layer-by-layer (LbL) films of poly(o-ethoxyaniline) (POEA), chitosan and chitosan-poly(methacrylic acid) (CS-PMAA) nanoparticles were produced. Because the adsorption of these LbL films on the glass sheet depends on ionic interactions and H-bonding, optimal conditions for the growth of multilayer films were a very important step of this study. The characteristics and properties of the LbL films were determined and its interactions with copper ions were studied by UV-Vis. spectroscopy. The properties of the films varied according to the form of chitosan, namely an aqueous solutions or a suspension of chitosan nanoparticles, was used for the film growth, demonstrating the versatility of this polymer and its good capacity to form thin films, alone or combined with POEA.