Effects of solvent vapor annealing on the optical properties and surface adhesion of conjugated D : A thin films.

A diketopyrrolopyrrole (DPP) and perylene diimide (PDI)-based molecule, denoted as PDI-DPP-PDI, was investigated as an electron acceptor material in bulk heterojunction (BHJ) solar cells, with poly[[4,8-bis [5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl] [2-(2-ethyl-1-oxohexyl)thieno[3,4-b]thiophenediyl]] (PBDTTT-CT) as an electron donor. The donor polymer and the acceptor molecule have complementary absorption spectra, which is an essential feature for energy collection in organic solar cells. However, AFM images indicated the presence of isolated and microsized PDI-DPP-PDI domains along the surface of the films, which reduced the power conversion efficiency. Therefore, to improve the homogenization of the acceptor along the film, a post-deposition treatment, denoted as solvent vapor annealing (SVA), was performed in a saturated atmosphere containing the vapour of an organic solvent for 3-10 minutes. This procedure changed the optical and morphological properties of the PBDTTT-CT : PDI-DPP-PDI active layer, resulting in increased power conversion efficiency values by more than 2.5 times (reaching 5.1%). Theoretical simulation pointed out that the experimental absorbance band localized at 580 nm, which appeared after SVA treatment, is possibly related to an intense simulated band with a maximum at 572 nm, resulting from a pair of transitions starting in the copolymer and ending in PDI-DPP-PDI, in regions where both are stacked at about 3 Å. The most significant natural transition orbitals (NTOs) related to these transitions indicated charge transfer character. Moreover, analyses carried out by power spectrum density (PDS) of images acquired from the SVA-treated film indicated that in the region of larger frequencies, across the length scale at around 30-70 nm, an additional fractal region appeared with a Ds of 0.95, indicating a flattened region, possibly related to changes in the overall conformation after SVA treatment. This indicates an improvement in the molecular packing, a feature not observed in the as-cast film. The analyses by force curve spectroscopy pointed out increased adhesion forces and adhesion energy in the PBDTTT-CT : PDI-DPP-PDI film after SVA treatment; this feature enhanced the interfacial interaction with the top electrodes, reflecting improved charge extraction in the photovoltaic device.

NH3 Sensor Based on rGO-PANI Composite with Improved Sensitivity.

This work reports on a reduced graphene oxide and poly(aniline) composite (rGO-PANI), with rGO clusters inserted between PANI chains. These clusters were formed due the plasticizing effect of N-methyl-2-pyrrolidone (NMP) solvent, which was added during the synthesis. Further, this composite was processed as thin film onto an interdigitated electrode array and used as the sensitive layer for ammonia gas, presenting sensitivity of 250% at 100 ppm, a response time of 97 s, and a lowest detection limit of 5 ppm. The PANI deprotonation process, upon exposure to NH3, rGO, also contributed by improving the sensitivity due its higher surface area and the presence of carboxylic acids. This allowed for the interaction between the hydrogen of NH3 (nucleophilic character) and the -COOH groups (electrophilic character) from the rGO surface, thereby introducing a promising sensing composite for amine-based gases.

Manual asymmetry in older adults on a complex coincidence-anticipation task.

Age-related asymmetrical functional decline was tested in a sample of 57 right-handed volunteers between 65 and 85 years of age. Participants performed a complex coincidence-anticipation (CA) task with both preferred and non-preferred hands. Results demonstrated that the proficiency of a complex CA task was similar for the 2 age groups, but different for the 2 hands. The non-preferred hand was more proficient for temporal accuracy but not for response timing, which was similar for both hands. Moreover, the lack of interaction between age and hand both in response timing and response accuracy reveal symmetric performance across ages.

Evaluating Aflatoxin Gene Expression in Aspergillus Section Flavi.

The determination of aflatoxin production ability and differentiation of aflatoxigenic strains can be assessed by monitoring the expression of one or several key genes using reverse transcription polymerase chain reaction (RT-PCR). We herein describe the methods for RNA induction, extraction, and quality determination, and the RT-PCR conditions used to evaluate the ability of a given Aspergillus strain to produce aflatoxins.

Efeito da prática regular de atividade física no desempenho motor em idosos / Effect of regular practice of physical activity in motor performance in the elderly

Os efeitos do envelhecimento contribuem para uma maior lentidão no processamento da informação, nomeadamente ao nível do tratamento da informação sensorial, decisão e programação dos movimentos. O presente estudo investigou o tempo de reação simples e o tempo de antecipação-coincidência, em idosos praticantes e não praticantes de atividade física. Constituíram a amostra 66 idosos de ambos os sexos com idade cronológica entre os 65 e os 89 anos (M = 74,3; SD = 6,0 anos), dos quais 34 eram praticantes de atividade física regular e 32 não praticantes de atividade física regular. Os instrumentos utilizados foram o "Multi-Choice Reaction Time Apparatus" para avaliar o tempo de reação simples (TRS) e o "Bassin Anticipation Timer" para avaliar a antecipação-coincidência (AC). Estas capacidades são relevantes no bem-estar e funcionalidade da população mais envelhecida. Cada participante realizou com a mão preferida um total de seis tentativas na tarefa de TRS e 20 tentativas na tarefa de AC. Os resultados revelaram que o grupo de praticantes de atividade física demonstrou desempenhos superiores tanto na tarefa de TRS como na tarefa de AC. O sexo foi fator influente apenas no grupo de praticantes no desempenho das duas tarefas, sendo os homens mais rápidos e precisos do que as mulheres. Um processamento da informação mais rápido nos homens pode estar na base destes resultados. Como as duas capacidades avaliadas neste estudo constituem uma expressão da integridade funcional do sistema nervoso central, os resultados sugerem que a prática de atividades motoras sistemáticas pode retardar e ser um importante protetor contra os efeitos de envelhecimento nos processos perceptivo-motores inerentes a este tipo de tarefas.

The slowing down in information processing, particularly at the level of sensory information, decision and movement programming in elderly is a consequence of aging. The present study investigated simple reaction time and coincidence-anticipation in 44 physical active and in 33 non-physical active male and female elderly individuals, with chronological age between 60- to 89-years-old (M = 73.7; SD = 7.4 years). The Multi-Choice Reaction Time was used to measure simple reaction time (SRT) and the Bassin Anticipation Timer was used to evaluate coincidence-anticipation (CA). These abilities play a major role in the functionality and well being of the elderly. Each participant performed with the preferred hand a total of six trials in the SRT task and twenty trials in the CA task. The results showed that the physical active group outperformed the non-physical active group in both tasks and only in this group males were better than females. A faster information process in males could underlie this outcome. Since the two abilities evaluated in this study constitute an expression of the functional integrity of the central nervous system, the results suggest that systematic practice of physical activity can delay and be an important protector against the effects of aging in the perceptual-motor processes involved in this type of tasks.

Localização sonora em usuários de aparelhos de amplificação sonora individual / Sound localization by hearing aid users

OBJETIVO: comparar o desempenho, no teste de localização de fontes sonoras, de usuários de aparelhos de amplificação sonora individual (AASI) do tipo retroauricular e intracanal, com o desempenho de ouvintes normais, nos planos espaciais horizontal e sagital mediano, para as frequências de 500, 2.000 e 4.500 Hz; e correlacionar os acertos no teste de localização sonora com o tempo de uso dos AASI. MÉTODOS: foram testados oito ouvintes normais e 20 usuários de próteses auditivas, subdivididos em dois grupos. Um formado por 10 indivíduos usuários de próteses auditivas do tipo intracanal e o outro grupo formado por 10 usuários de próteses auditivas do tipo retroauricular. Todos foram submetidos ao teste de localização de fontes sonoras, no qual foram apresentados, aleatoriamente, três tipos de ondas quadradas, com frequências fundamentais em 0,5 kHz, 2 kHz e 4,5 kHz, na intensidade de 70 dBA. RESULTADOS: encontrou-se percentuais de acertos médios de 78,4 por cento, 72,2 por cento e 72,9 por cento para os ouvintes normais, em 0,5 kHz, 2 kHz e 4,5 kHz, respectivamente e 40,1 por cento, 39,4 por cento e 41,7 por cento para os usuários de aparelho de amplificação sonora individual. Quanto aos tipos de aparelhos, os usuários do modelo intracanal acertaram a origem da fonte sonora em 47,2 por cento das vezes e os usuários do modelo retroauricular em 37,4 por cento das vezes. Não foi observada correlação entre o percentual de acertos no teste de localização sonora e o tempo de uso da prótese auditiva. CONCLUSÃO: ouvintes normais localizam as fontes sonoras de maneira mais eficiente que os usuários de aparelho de amplificação sonora individual e, dentre estes, os que utilizam o modelo intracanal obtiveram melhor desempenho. Além disso, o tempo de uso não interferiu no desempenho para localizar a origem das fontes sonoras.

PURPOSE: to compare the sound localization performance of hearing aids users, with the performance of normal hearing in the horizontal and sagittal planes, at 0.5, 2 and 4.5 Hz; to correlate the correct responses in sound localization tasks and the use time of hearing aids. METHODS: eight normal hearing subjects and 20 hearing aid users were tested, subdivided into groups of 10 in-the-canal (ITC) hearing aid users and 10 behind-the-ear (BTE) hearing aid users. All subjects were tested with a sound localization device which had three types of square waves with fundamental frequencies at 0.5 kHz, 2 kHz and 4.5 kHz, at 70 dBA. RESULTS: the rate of correct responses in sound localization tasks was 78.4 percent, 72.2 percent and 72.9 percent for normal hearing subjects, at 0.5 kHz, 2 kHz and 4.5 kHz, respectively, and 40.1 percent, 39.4 percent, and 41.7 percent for hearing aid users. As for the types of hearing aids, users of ITC type hit the correctly sound localization in 47.2 percent and user of BTE type in 37.4 percent. CONCLUSION: normal hearing subjects locate sound sources more efficiently than hearing aid users, and among these, those using the ITC type obtained better performance. Moreover, the time of use does not interfere with the performance for locating the sound sources.

Manual asymmetry in a complex coincidence-anticipation task: handedness and gender effects.

This study investigated the effects of handedness and gender on manual asymmetry in the performance of a complex coincidence-anticipation task. Left-handed (N=63) and right-handed (N=93) undergraduate students (78 males, 78 females) were required to press six buttons sequentially in conjunction with visual stimulation provided by a coincidence-anticipation apparatus. Participants were further separated into subgroups based on the degree of hand preference. Timing accuracy (AE, CE, VE) and timing response (IT, MT, AT) were analysed. Results showed that, concerning accuracy, (i) strong left-handers were more accurate than the other groups; (ii) performance with the preferred hand was superior to that of the non-preferred hand; and (iii) males outperformed females. Concerning timing response, (i) the preferred hand was faster than the non-preferred hand for movement time and (ii) males were faster in initiating the movement than females. These findings indicate that coincidence-anticipation competence appears to be influenced by hand preference, performing hand, and gender. In addition, findings are discussed in the framework of the hemispheric functional lateralisation for the planning and organisation of movement execution.

Water-soluble dendritic core-shell-type architectures based on polyglycerol for solubilization of hydrophobic drugs.

Since many potential drugs are poorly water soluble, there is a high demand for solubilization agents. Here, we describe the synthesis of dendritic core-shell-type architectures based on hyperbranched polyglycerol for the solubilization of hydrophobic drugs. Amphiphilic macromolecules containing hydrophobic biphenyl groups in the core were synthesized in an efficient three- or four-step procedure by employing Suzuki-coupling reactions. These species were then used to solubilize the commercial drug nimodipine, a calcium antagonist used for the treatment of heart diseases and neurological deficits. Pyrene was also used as a hydrophobic model compound. It turned out that the transport properties of the dendritic polyglycerol derivatives, which are based on hydrophobic host-guest interactions, depend strongly on the degree and type of core functionalization. In the case of the multifunctional nimodipine, additional specific polymer-drug interactions could be tailored by this flexible core design, as detected by UV spectroscopy. The enhancement of solubilization increased 300-fold for nimodipine and 6000-fold for pyrene at a polymer concentration of 10 wt%. The sizes of the polymer-drug complexes were determined by both dynamic light scattering (DLS) experiments and transmission electron microscopy (TEM), and extremely well-defined aggregates with diameters of approximately 10 nm in the presence of a drug were observed. These findings together with a low critical aggregate concentration of 4x10(-6) mol L-1 indicate the controlled self-assembly of the presented amphiphilic dendritic core-shell-type architectures rather than a unimolecular transport behavior.