Quantum Rate Theory and Electron-Transfer Dynamics: A Theoretical and Experimental Approach for Quantum Electrochemistry

Quantum rate theory is based on a first-principle quantum mechanical rate concept that comprises with the Planck-Einstein relationship $E = h\nu$, where $\nu = e^2/hC_q$ is a frequency associated with the quantum capacitance $C_q$ and $E = e^2/C_q$ is the energy associated with $\nu$. For a single state mode of transmittance, $e^2/C_q$ corresponds to the chemical potential differences $\Delta \mu$ between donor and acceptor state levels comprising an electrochemical reaction. The latter assumption implies quantum electrodynamics within a particular quantum transport mode intrinsically coupled to the electron-transfer rate of electrochemical reactions that have not been considered thus far. Here it is demonstrated that the consideration of this inherent quantum transport is key to obtaining an in-depth understanding of the electron transfer phenomenon. Finally, the theory is validated through its description of electron transfer, quantum conductance, and capacitance in different electro-active molecular films

Grain size effect on the electrical response of SnO2 thin and thick film gas sensors

Porous nano and micro crystalline tin oxide films were deposited by RF Magnetron Sputtering and doctor blade techniques, respectively. Electrical resistance and impedance spectroscopy measurements, as a function of temperature and atmosphere, were performed in order to determine the influence of the microstructure and working conditions over the electrical response of the sensors. The conductivity of all samples increases with the temperature and decreases in oxygen, as expected for an n-type semiconducting material. The impedance plots indicated the existence of two time constants related to the grains and the grain boundaries. The Nyquist diagrams at low frequencies revealed the changes that took place in the grain boundary region, with the contribution of the grains being indicated by the formation of a second semicircle at high frequencies. The better sensing performance of the doctor bladed samples can be explained by their lower initial resistance values, bigger grain sizes and higher porosity.Fil: Savu, Raluca. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Ponce, Miguel Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Joanni, Ednan. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Bueno, Paulo Roberto. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Castro, Miriam Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Cilense, Mario. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Varela, Jose Arana. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Longo, Elson. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi

Impact of Surface Roughness on the Self-Assembling of Molecular Films onto Gold Electrodes for Label-Free Biosensing Applications

The properties of molecular films assembled over gold electrode surfaces are prone to reflect fabrication characteristics. Here we show the importance of controlling electrode surface characteristics of a gold interface destined to label-free electrochemical biosensing applications and how to decrease the effect of the roughness on the properties of the interface by using redox composite materials within 5 to 10 nm in thickness. This controlling of surface characteristics allows us to fabricate reproducible, disposable printed circuit board microelectrodes for label-free electrochemical capacitive assays, which are specifically aimed at applications in point-of-care molecular diagnostic devices. We demonstrate that both the electrochemical roughness factor and the mechanical roughness root mean square of the surface are useful parameters for the quality control of molecularly assembled films and the chemical modification of the surface. For instance, the measured ionic capacitance of gold interfaces is linear as a function of an electrochemical roughness factor lower than ca. 2. On the other hand, roughness factor values higher than ca. 2 lead to a random ionic capacitance outcome. A similar trend of presenting reproducible or irreproducible electrochemical behaviour, wherein a roughness threshold exists, is perceived for charge transfer resistance whether the interfacial redox activity is blocked with a dielectric molecular layer. It was also demonstrated that redox reversibility of gold interfaces is sensitive to the roughness root mean square. Finally, we also confirmed that if the roughness is controlled below a well-defined threshold or if a film thickness (within 5 to 10 nm) is assembled over the surface, the sensing properties are reproducible in micro-fabricated printed circuit board electrodes used in assaying C-reactive protein in human serum. This is an important upshot that permit the microfabrication of cost-effective microelectrodes for label-free electrochemical capacitive biosensors, within the capability to be further integrated into Lab-on-PCB microsystems

Quantum rate electrodynamics and resonant junction electronics of heterocyclic molecules

"This version, v2"Quantum rate theory encompasses the electron-transfer rate constant concept of electrochemical reactions as a particular setting, besides demonstrating that the electrodynamics of these reactions obey relativistic quantum mechanical rules. The theory predicts a frequency ν = E/h for electron- transfer reactions, in which E = e2/Cq is the energy associated with the density-of-states Cq/e2 and Cq is the quantum capacitance of the electrochemical junctions. This work demonstrates that the ν = E/h frequency of the intermolecular charge transfer of push-pull heterocyclic compounds, assembled over conducting electrodes, follows the above-stated quantum rate electrodynamic prin- ciples. Astonishingly, the differences between the molecular junction electronics formed by push-pull molecules and the electrodynamics of electrochemical reactions observed in redox-active modified electrodes are solely owing to an adiabatic setting (strictly following Landauer’s ballistic presump- tion) of the quantum conductance in the push-pull molecular junctions. An appropriate electrolyte field-effect screening environment accounts for the resonant quantum conductance dynamics of the molecule-bridge-electrode structure, in which the intermolecular charge transfer dynamics within the frontier molecular orbital of push-pull heterocyclic molecules follow relativistic quantum mechanics in agreement with the quantum rate theory.PRB is grateful to the Sao Paulo State Research Foundation (FAPESP) (for grants 2017/24839-0) and the National Council for Scientific and Technological (CNPq). Edgar Nieto acknowledges FAPESP for his PhD scholarship (grant 2018/24525-9). Thanks are also due to Fundação para a Ciência e Tecnologia (FCT) and to FEDER-COMPETE for financial support through the research center CQUM (UID/QUI/0686/2016) and (UID/QUI/0686/2020). The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project Nº 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC)

GESTÃO UNIVERSITÁRIA E INOVAÇÃO: UM ESTUDO IMPÍRICO EM UM HOSPITAL UNIVERSITÁRIO

Devido ao cenário competitivo global contemporâneo, a gestão universitária e a inovação é um tema que merece ser pesquisado em maior abrangência. Nesse sentido a pesquisa teve como objetivo contribuir para o entendimento da gestão universitária e da inovação no contexto hospitalar por meio da identificação das inovações realizadas em um hospital universitário. Sendo a inovação norteada pela habilidade de fazer relações, de visualizar oportunidades, nas instituições hospitalares esta age como meio de melhorar a qualidade e segurança dos serviços oferecidos para a população. Para que o objetivo proposto fosse atingido, optou-se pela abordagem qualitativa de natureza exploratória. Foram realizadas observações não participantes, e entrevistas com os gestores do hospital procurando identificar as suas percepções quanto às inovações realizadas. Os resultados demostraram que mesmo em um ambiente hospitalar universitário são realizadas várias inovações visualizando o bem estar do público interno e externo

Determination of kinetic and thermodynamic parameters of L-cysteine adsorption onto gold by the qcm technique

This article discusses the adsorption kinetics of a L-cysteine monolayer onto a gold surface by means of information obtained through the QCM technique. The results indicate that the adsorption process is rapid and follows the Langmuir isotherm, in which adsorption and desorption are considered. From these measurements the following parameter values were obtained: k d = (4.2 ± 0.4) x 10-3 s-1, k a = 75 ± 6 M-1 s-1, Keq=(1.8 ± 0.3) x 10(4) M-1 and ΔGads = - (5.8 ± 0.2) kcal mol-1

Monitoria na Disciplina “Técnica Cirúrgica e Cirurgia Experimental”

Na monitoria da disciplina Técnica Cirúrgica e Cirurgia Experimental, alunos que foram aprovados no curso participam do ensino dos atuais discentes em atividades práticas. Um questionário de resposta voluntária inquiriu a motivação para o exercício da monitoria e a avaliação dos monitores sobre a atividade. Aceitaram participar dezenove monitores, de 2014 a 2015. Para 94,7% dos que responderam ao questionário, a monitoria atingiu o esperado ou o além do esperado, e todos indicam a monitoria a outros alunos da faculdade. Isso a caracteriza como fator positivo na formação dos participantes dessa atividade acadêmica. Essa boa avaliação associa-se ao maior aprendizado do aluno monitor sobre o conteúdo da disciplina, à melhoria da comunicação interpessoal e à maior vivência com a cirurgia que a monitoria proporciona. Aos alunos da disciplina, o ganho ao utilizar essa estratégia didática consiste na maior empatia que os monitores têm com aqueles que cursam a disciplina em comparação com os docentesIn the monitoring of the discipline Surgical Technique and Experimental Surgery, students that were previously approved in the course take part in the teaching of the current students in practical activities. A questionnaire with voluntary answer asked the motivation to participate in the monitoring and the evaluation of the activity by the monitors. Nineteen monitors accepted to participate, from 2014 and 2015. For 94.7% of the answers, monitoring reached the expected or better than expected and all the participants indicate monitoring to other college students. This fact shows that this academic activity is a positive factor in the formation of the participants. A positive evaluation associates with the enhanced learning of the discipline content by the monitor, the improving of interpersonal communication and the greater experience in surgery that the monitoring provides. To the students of the discipline, adopting this didactical strategy is better due to the greater empathy that monitors have with the students comparing with the professor

O que está subjacente à escolha do estudante pela profissão médica?

PURPOSE: To determine the reasons for choosing the medical profession by interviewing freshmen medical students from the Faculty of Medicine, University of São Paulo and investigating their socio-economic and psychological profiles, as well as to determine whether there are gender differences. METHOD: One hundred and sixty three freshmen medical students answered a questionnaire regarding their socio-economical profile. Of those, 30 female and 30 male students underwent a face-to-face interview regarding the career choice, the Thematic Apperception Test (TAT) and the 16 Personality Factor Questionnaire (16 PF). The results were analyzed qualitatively and by Mann-Whitney, chi2, Fisher's Exact, and r p coefficient tests. RESULTS: Most students were middle class, catholic, and had physicians in their families. Students of both genders had made an: early choice of the medical career and a persistence in taking exams many times, even after being discouraged. They also showed an awareness of the difficulties and limitations in developing their careers. The study revealed a strong valuation of the humanistic aspects of medicine; openness to new experiences; a deep personal identification with the choice of profession; a critical need for fulfillment in their careers; and conscious and unconscious desires to help people and be recognized for their usefulness, without being narcissistic. Female students were more sensitive (POBJETIVO: Determinar as razões da escolha da profissão médica em um grupo de alunos do primeiro ano de medicina da Faculdade de Medicina da Universidade de São Paulo, investigando o perfil sócio-econômico e psicológico, e as diferenças com relação ao gênero dos alunos. MÉTODO: Cento e sessenta e três alunos responderam a um questionário para avaliar seu perfil sócio-econômico. Destes, 30 mulheres e 30 homens submeteram-se a uma entrevista face a face sobre a escolha da profissão, ao Teste de Apercepção Temática (TAT) e ao teste 16 PF. Os resultados foram analisados qualitativamente e pelos testes de Mann-Whitney, chi2, Fisher's Exact e coeficiente r p. RESULTADOS: A maioria dos estudantes pertence à classe média, são católicos e possuem médicos na família. Estudantes de ambos os gêneros haviam escolhido precocemente a profissão e mostraram persistência para prestar o vestibular, mesmo quando desencorajados por terceiros. O estudo revelou consciência das dificuldades e limitações da carreira médica, bem como grande valorização dos aspectos humanísticos da medicina e espírito aberto a novas experiências. Verificou-se que a profissão ocupa um papel central em suas identidades, a relevância dada à satisfação profissional, o desejo consciente e inconsciente de ajudar os semelhantes e de serem reconhecidos por isso, sem a busca exclusiva de uma gratificação narcísica. As alunas apresentaram maior Brandura (

Determination of the mechanical properties of epsilon martensite by nanoindentation in shape memory stainless alloys

ABSTRACT This work presents a hardness study and elastic modulus for the ε-martensite and γ-austenite phases of an iron based shape memory alloy. Using instrumented indentation, it was possible to determine the hardness and elasticity modulus of these phases separately. The martensitic phase presented a hardness of 7.0 GPa and the austenitic phase presented a hardness of 3.0 GPa. The elastic modulus values were 202 and 137 GPa for the martensitic and austenitic phases, respectively.RESUMO Esse trabalho apresenta um estudo da dureza e do mee austenita-γ da liga inoxidável à base de ferro com efeito de memória de forma. Utilizando indentação instrumentada, foi possível determinar a dureza e o módulo de elasticidade das fases austenita-γ e martensita-ε separadamente. A fase martensítica apresentou uma dureza de 7,0 GPa, enquanto que a dureza da fase austenítica foi de 3,0 GPa. Os valores de módulo de elasticidade foram 202 e 137 GPa, para as fases martensita e austenita, respectivamente.3944Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

LED lights in the in vitro multiplication of three banana cultivars

1 recurso en línea (páginas 247-252) : ilustraciones color.Os diodos emissores de luz (LEDs) são considerados a mais nova e promissora fonte de luz para o cultivo in vitro de plantas, por apresentarem uma longa lista de benefícios e afetarem positivamente o crescimento dos explantes. O objetivo deste trabalho foi avaliar o uso dos LEDs como fonte de luz alternativa às lâmpadas fluorescentes na multiplicação de três cultivares de bananeira. A multiplicação das cultivares Grande Naine, FHIA 18 e Prata Anã foi realizada em meio MS (Murashige e Skoog) acrescido de 30 g L-1 de sacarose, 100 mg L-1 de mio-inositol, 7 g L-1 de ágar e 6 mg L-1 de BAP, por três subcultivos sucessivos de 30 dias, sob cinco fontes de luz (LEDs azuis-EDEB 3LA1 470 nm, LEDs verdes-EDET 3LA1 530 nm, LEDs vermelhos-EDER 3LA3 630 nm, lâmpadas fluorescentes Growlux e lâmpadas fluorescentes brancas), fotoperíodo de 16 horas, temperatura de 25±2ºC e intensidade luminosa de 20 μmol m-2 s-1. Utilizou-se delineamento inteiramente ao acaso, em esquema fatorial 5×3 (fonte de luz × cultivar), com cinco repetições. Para as três cultivares de bananeira multiplicadas, observou-se que o número de brotações e folhas não foi influenciado pelo tipo de luz. O maior número de brotações formado foi obtido com a cultivar Grande Naine (2,6 brotos/explante), não havendo diferença entre a cv. FHIA 18 e Prata Anã (1,4 e 1,3 brotos/explante). Determinou-se significância entre os fatores cultivar e fonte de luz para o comprimento da brotação, sendo o maior comprimento obtido com ‘Prata Anã’ cultivadas sob os LEDs verdes.Light emitting diodes (LEDs) are considered the most promising new source of light for the in vitro cultivation of plants because they have a long list of benefits and positively affect the growth of explants. The objective of this study was to evaluate the use of LEDs as an alternative light source, using fluorescent lamps in the multiplication of three banana cultivars. The Grande Naine, FHIA 18 and Prata Anã cultivars were placed in an MS (Murashige and Skoog) medium with 30 g L-1 sucrose, 100 mg L-1 myo-inositol, 7 g L-1 agar and 6 mg L-1 BAP; three successive subcultures were carried out for 30 days under five light sources (blue-EDEB LEDs 3LA1 470 nm, green-TEDS LEDs 3LA1 530 nm, red-EDER LEDs 3LA3 630 nm, Growlux fluorescent lamps and white fluorescent lamps), with a 16 hour photoperiod, temperature of 25±2°C and light intensity of 20 μmol m-2 s-1. The design was completely randomized with a 5×3 factorial (light source × cultivar), with five repetitions. For all three cultivars, it was observed that the number of shoots and leaves was not influenced by the type of light. The highest number of formed shoots was obtained with the cultivar Grande Naine (2.6 buds/explant), with no difference between cv. FHIA 18 and Prata Anã (1.4 and 1.3 shoots/explant). There was a significant difference between the cultivars and light source for the length of budding; the longest length was obtained with Prata Anã, grown under green LEDs.Bibliografía y webgrafía: páginas 251-252