Printed, Flexible Lactate Sensors: Design Considerations Before Performing On-Body Measurements.

This work reports the process of sensor development, optimization, and characterization before the transition to on-body measurements can be made. Sensors using lactate oxidase as a sensing mechanism and tetrathiafulvalene as a mediator were optimized for sporting applications. Optimized sensors show linear range up to 24 mM lactate and sensitivity of 4.8 μA/mM which normalizes to 68 μA*cm-2/mM when accounting for surface area of the sensor. The optimized sensors were characterized 3 different ways: using commercially available reference and counter electrodes, using printed reference and counter electrodes, and using a printed reference electrode with no counter electrode. Sensors intended for measuring sweat must be selective in the presence of sweat constituents. Thus, in addition to traditional characterization in pH 7.0 buffer, we characterized sensor performance in solutions intended to approximate sweat. Sensor performance in pH 7.0 buffer solution was not reflective of sensor performance in artificial sweat, indicating that further characterization is necessary between sensor measurement in pH 7.0 buffer and on-body measurements. Furthermore, we performed enzyme activity measurements and sensor measurements concurrently in five different salts individually, finding that while NH4Cl and MgCl2 do not affect enzyme activity or sensor performance in physiologically relevant ranges of salt concentration, NaCl concentration or KCl concentration decreases enzyme activity and sensor current. On the other hand, CaCl2 induced a nonlinear change in sensor performance and enzyme activity with increasing salt concentration

Propriedades ópticas e elétricas de copolímeros baseados em unidades de Tiofeno, Fluoreno e Fenileno para aplicação em dispositivos Fotovoltaicos

Resumo: Neste trabalho, uma nova série de copolímeros foi investigada como camada doadora de elétrons em dispositivos fotovoltaicos. Por meio da copolimerização é possível combinar propriedades e comportamentos de diferentes materiais. Os copolímeros usados neste estudo consistem de unidades de tiofeno, fenileno e fluoreno, nos quais a quantidade de tiofeno foi mantida constante e variou-se a razão de unidades de fenileno e fluoreno. Para cada copolímero, apresentamos resultados em três estruturas distintas: monocamada, bicamada e heterojunção. Usando moléculas de C60 depositadas por evaporação como aceitadores de elétrons na estrutura bicamada, demonstrou-se o efeito de diferentes espessuras no desempenho dos dispositivos. O transporte elétrico nos dispositivos bicamada foi analisado a partir de um modelo de transporte e injeção de cargas, indicando que há uma dependência das mobilidades efetivas de elétrons e de buracos em função da espessura dos filmes. No sistema de heterojunção, a molécula metanofulereno éster metílico do ácido 6,6- fenil-C61 butírico (PCBM) foi empregada como aceitadora de elétrons em mistura com os copolímeros e os resultados obtidos demonstram boa eficiência de oto-conversão. Para um dos copolímeros, foi encontrada uma concentração ótima de moléculas de PCBM que podem ser adicionadas ao copolímero para maximizar a foto-corrente

Células solares orgânicas baseadas nas estruturas heterojunção em bicamada e heterojunção de volume

Orientadora: Profª. Drª. Lucimara Stolz RomanTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Curso de Pós-Graduação em Física. Defesa: Curitiba, 21/07/2014Inclui referênciasResumo: Neste trabalho, dispositivos fotovoltaicos orgânicos baseados na combinação de materiais doadores e aceitadores de elétrons são apresentados em duas estruturas distintas conhecidas como heterojunção em bicamada e heterojunção de volume. Os dispositivos em bicamada foram caracterizados tendo como camada fotossensível quatro copolímeros baseados em unidades de fluoreno e tiofeno. O primeiro dispositivo apresentado é composto pela bicamada do polímero comercial F8T2 com o fulereno C60. Nos dispositivos de F8T2, foi investigado o efeito de diferentes espessuras da camada polimérica no desempenho dos dispositivos e foi possível estimar valores de mobilidade de portadores de cargas efetiva para cada espessura, sendo que o valor mais alto foi encontrado para a espessura igual a 30 nm. Com essa mesma estrutura em bicamada foi possível a fabricação e caracterização de dispositivos em substratos flexíveis. Os outros três materiais estudados em heterojunção bicamada são polímeros compostos por unidades de fluoreno e tiofeno, nos quais a quantidade de tiofenos é sistematicamente variada: LaPPS 23 (fluoreno- tiofeno), LaPPS 43 (fluoreno-bitiofeno) e LaPPS 45 (fluoreno-tertiofeno). Quando não são submetidos a tratamento térmico, a camada fotossensível composta pelo material com maior quantidade de tiofenos (LaPPS 45) apresentou maior eficiência de conversão de potência. No entanto, quando os filmes são submetidos a tratamento térmico, o melhor desempenho foi encontrado para o LaPPS 43 (200 °C) devido a um aumento considerável na mobilidade de buracos neste material. Dispositivos em heterojunção de volume baseados na mistura do F8T2 com o fulereno PCBM foram testados com diferentes temperaturas de tratamento térmico da camada fotossensível. Observou-se a melhoria do desempenho dos dispositivos com o aumento da temperatura de tratamento térmico. Nanopartículas baseadas na mistura de polímero-polímero e polímero-fulereno foram sintetizadas em meio aquoso pelo método da miniemulsão. Dispositivos fotovoltaicos foram testados com filmes depositados por centrifugação e por doctor blade. As propriedades de transporte elétrico nestas nanopartículas foram descritas por um modelo fenomenológico que relaciona a morfologia intrínseca dos filmes às respostas fotovoltaicas.Abstract: In this work, we present organic photovoltaic devices based on the combination of an electron donor and an acceptor material in two distinct structures known as bilayer heterojunction and bulk heterojunction. The bilayer devices have been characterized based on four copolymers composed of fluorene and thiophene units. First, it is presented the bilayer device based on the commercial polymer F8T2 with the fullerene C60. In these F8T2 devices, the effect on the device performance of different polymer layer thickness was investigated, and it was possible to estimate the effective charge carrier mobility for each thickness, whereas the highest value was found for the polymer thickness of 30 nm. In the same bilayer structure, it was possible to manufacture and characterize devices made on flexible substrates. The other three materials tested in the bilayer heterojunction are polymers composed of fluorene and thiophene units in which the amount of thiophene unites is systematically varied: Lapps 23 (fluorene-thiophene) Lapps 43 (fluorene-bithiophene), and Lapps 45 (fluorene-terthiophene). Among them, the highest power conversion efficiency for the as cast device was found for the one with the highest amount of thiophene units (Lapps 45). However, for annealed devices, the best performance was found for LaPPS 43 (200 °C) due to the remarkable increase in the hole mobility value for this material. Bulk heterojunction devices based on the blend of F8T2 with the fullerene PCBM were tested at different annealing temperatures of the blend layer. It was found that device efficiency improves with the increase in the annealing temperature. Nanoparticles based on polymer-polymer and polymer-fullerene blends have been synthesized in aqueous medium by the miniemulsion method. Photovoltaic devices have been tested whereas the nanoparticle films were deposited by spin coating and by doctor blade coating. The electrical transport properties of the nanoparticle films are fully described by a phenomenological model that relates intrinsic film morphology to the photovoltaic response

An EMG Gesture Recognition System with Flexible High-Density Sensors and Brain-Inspired High-Dimensional Classifier

EMG-based gesture recognition shows promise for human-machine interaction. Systems are often afflicted by signal and electrode variability which degrades performance over time. We present an end-to-end system combating this variability using a large-area, high-density sensor array and a robust classification algorithm. EMG electrodes are fabricated on a flexible substrate and interfaced to a custom wireless device for 64-channel signal acquisition and streaming. We use brain-inspired high-dimensional (HD) computing for processing EMG features in one-shot learning. The HD algorithm is tolerant to noise and electrode misplacement and can quickly learn from few gestures without gradient descent or back-propagation. We achieve an average classification accuracy of 96.64% for five gestures, with only 7% degradation when training and testing across different days. Our system maintains this accuracy when trained with only three trials of gestures; it also demonstrates comparable accuracy with the state-of-the-art when trained with one trial

Thickness Effect on F8T2/C 60

Copolymers based on fluorene-thiophene units have presented promising efficiencies in photovoltaic devices applications. They present good transport properties mainly after thermal treatment of the polymer films. Here, we investigate the properties of bilayer devices formed by the heterojunction of the polymer F8T2 with variable thickness and the fullerene. The series resistance of the equivalent circuit associated with the device increases as the polymer film gets thicker. The current-voltage characteristics of the bilayer devices follow the Mott-Gurney law of SCLC. For the best performing device we measured 2.1% of power conversion efficiency

A Platform to Study the Effects of Electrical Stimulation on Immune Cell Activation During Wound Healing.

Wound healing is a complex process involving diverse changes in multiple cell types where the application of electric fields has been shown to accelerate wound closure. To define the efficacy of therapies based on electric fields, it would be valuable to have a platform to systematically study the effects of electrical stimulation (ES) upon the inflammation phase and the activation of signaling mediators. Here, an in vivo ES model in which flexible electrodes are applied to an animal model for monitoring inflammation in a wound is reported on. Subcutaneous implants of polyvinyl alcohol sponges elicit inflammation response as defined by the infiltration of leukocytes. The wound site is subjected to electric fields using two types of additively fabricated flexible electrode arrays. The sponges are then harvested for flow cytometry analysis to identify changes in the phosphorylation state of intracellular targets. This platform enables studies of molecular mechanisms, as it shows that an application of low-frequency ES ≤0.5 Hz increases phosphorylation of Erk proteins in recruited leukocytes, identifying a signaling pathway that is activated during the healing process

FIV establishes a latent infection in feline peripheral blood CD4+ T lymphocytes in vivo during the asymptomatic phase of infection

<p>Abstract</p> <p>Background</p> <p>Feline immunodeficiency virus (FIV) is a lentivirus of cats that establishes a lifelong persistent infection with immunologic impairment.</p> <p>Results</p> <p>In an approximately 2 year-long experimental infection study, cats infected with a biological isolate of FIV clade C demonstrated undetectable plasma viral loads from 10 months post-infection onward. Viral DNA was detected in CD4+CD25+ and CD4+CD25- T cells isolated from infected cats whereas viral RNA was not detected at multiple time points during the early chronic phase of infection. Viral transcription could be reactivated in latently infected CD4+ T cells <it>ex vivo </it>as demonstrated by detectable FIV <it>gag </it>RNA and 2-long terminal repeat (LTR) circle junctions. Viral LTR and <it>gag </it>sequences amplified from peripheral blood mononuclear cells during early and chronic stages of infection demonstrated minimal to no viral sequence variation.</p> <p>Conclusions</p> <p>Collectively, these findings are consistent with FIV latency in peripheral blood CD4+ T cells isolated from chronically infected cats. The ability to isolate latently FIV-infected CD4+ T lymphocytes from FIV-infected cats provides a platform for the study of <it>in vivo </it>mechanisms of lentiviral latency.</p

Breast cancer risk variants at 6q25 display different phenotype associations and regulate ESR1, RMND1 and CCDC170.

We analyzed 3,872 common genetic variants across the ESR1 locus (encoding estrogen receptor α) in 118,816 subjects from three international consortia. We found evidence for at least five independent causal variants, each associated with different phenotype sets, including estrogen receptor (ER(+) or ER(-)) and human ERBB2 (HER2(+) or HER2(-)) tumor subtypes, mammographic density and tumor grade. The best candidate causal variants for ER(-) tumors lie in four separate enhancer elements, and their risk alleles reduce expression of ESR1, RMND1 and CCDC170, whereas the risk alleles of the strongest candidates for the remaining independent causal variant disrupt a silencer element and putatively increase ESR1 and RMND1 expression.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/ng.352

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements