The influence of anesthetics, neurotransmitters and antibiotics on the relaxation processes in lipid membranes

In the proximity of melting transitions of artificial and biological membranes fluctuations in enthalpy, area, volume and concentration are enhanced. This results in domain formation, changes of the elastic constants, changes in permeability and slowing down of relaxation processes. In this study we used pressure perturbation calorimetry to investigate the relaxation time scale after a jump into the melting transition regime of artificial lipid membranes. This time corresponds to the characteristic rate of domain growth. The studies were performed on single-component large unilamellar and multilamellar vesicle systems with and without the addition of small molecules such as general anesthetics, neurotransmitters and antibiotics. These drugs interact with membranes and affect melting points and profiles. In all systems we found that heat capacity and relaxation times are related to each other in a simple manner. The maximum relaxation time depends on the cooperativity of the heat capacity profile and decreases with a broadening of the transition. For this reason the influence of a drug on the time scale of domain formation processes can be understood on the basis of their influence on the heat capacity profile. This allows estimations of the time scale of domain formation processes in biological membranes.Comment: 12 pages, 6 figure

Optimization of a high work function solution processed vanadium oxide hole-extracting layer for small molecule and polymer organic photovoltaic cells

We report a method of fabricating a high work function, solution processable vanadium oxide (V2Ox(sol)) hole-extracting layer. The atmospheric processing conditions of film preparation have a critical influence on the electronic structure and stoichiometry of the V2Ox(sol), with a direct impact on organic photovoltaic (OPV) cell performance. Combined Kelvin probe (KP) and ultraviolet photoemission spectroscopy (UPS) measurements reveal a high work function, n-type character for the thin films, analogous to previously reported thermally evaporated transition metal oxides. Additional states within the band gap of V2Ox(sol) are observed in the UPS spectra and are demonstrated using X-ray photoelectron spectroscopy (XPS) to be due to the substoichiometric nature of V2Ox(sol). The optimized V2Ox(sol) layer performance is compared directly to bare indium–tin oxide (ITO), poly(ethyleneoxythiophene):poly(styrenesulfonate) (PEDOT:PSS), and thermally evaporated molybdenum oxide (MoOx) interfaces in both small molecule/fullerene and polymer/fullerene structures. OPV cells incorporating V2Ox(sol) are reported to achieve favorable initial cell performance and cell stability attributes

Aproximação ao conceito de fractal através da experimentação: uma abordagem didática

The seizure of the concept of fractal allows you to establish a theoretical framework for the promotion of dynamic processes of generation and transformation of form. From a didactic interest, we sought to identify and analyze a tool of automated generation of fractal forms could contribute significantly to lay users in programming, understanding the concept of fractal. Drawing on constructivist theories of learning / teaching aimed to observe the potential of this tool to effectively approach to such concepts. A systematic held in the form of concept maps, is constituted as a learning object for the subject in question

A comparison of detomidine in combination with saline, morphine or methadone in horses submitted to experimental oral stimuli

This study aimed to compare the sedative and cardiopulmonary effects of detomidine in combination with saline, morphine or methadone and to determine whether the addition of these opioids increases the degree of sedation in horses submitted to experimental oral stimuli. In a blinded, randomized, experimental study, six adult mares were evaluated using a crossover design with at least 15 days between trials: 10?g/kg detomidine in combination with saline (D/SAL), 0.1mg/kg morphine (D/ MORPH) or 0.1mg/kg methadone (D/METH). The degree of sedation, response to oral stimuli and cardiopulmonary parameters were monitored for 120 minutes. Parametric data were analyzed using the ANOVA and Tukey’s tests, and non- parametric data were analyzed with the Kruskal-Wallis and Friedman’s tests with the post-Dunn test (P<0.05). The degree of sedation was significantly greater for the D/SAL than for the D/MORPH and D/METH treatments at 30 min. The horses´ responses to the oral stimuli decreased significantly following all treatments at 5 and 30 min from baseline values. The heart rate, respiratory rate, arterial pH and blood gas variables were all similar among the treatment groups. Mean arterial blood pressure was significantly higher in the D/MORPH group when compared with the D/SAL group between 75 and 120 min. It was concluded that all treatments provided sedative effects with mild cardiopulmonary changes. However the addition of morphine or methadone to detomidine did not improve the degree of sedation in horses submitted to experimental oral stimuli.Objetivou-se comparar os efeitos sedativos e cardiorrespiratórios da detomidina associada à solução salina, à morfina ou à metadona e determinar se a associação desses opioides poderia incrementar o grau de sedação em cavalos submetidos aos estímulos na cavidade oral. Em estudo cego, com delineamento aleatório foram avaliadas 06 éguas, com intervalo mínimo de 15 dias entre cada avaliação, sendo submetidos aos protocolos de sedação com detomidina (10mg/kg, IV) associada à solução salina (D/SAL), a 0,1mg/kg (IV) de morfina (D/MORF) ou a 0,1mg/kg (IV) de metadona (D/MET). Foram avaliados, durante 120 minutos: grau de sedação, resposta aos estímulos orais e parâmetros cardiorrespiratórios. A estatística foi realizada com análise de variância, teste de Tukey e análise de medidas repetidas, para as variáveis paramétricas. Para as variáveis não paramétricas foram empregados os testes de Kruskal-Wallis e de Friedman com contrastes pelo método de Dunn (P<0,05). O efeito sedativo foi significativamente superior no D/SAL em relação ao D/MORF e D/MET aos 30 minutos após a administração dos fármacos. A resposta dos animais perante os estímulos feitos na cavidade oral diminuiu significativamente aos 5 e 30 minutos em relação ao basal em todos os tratamentos. A frequência cardíaca e respiratória, bem como as variáveis hemogasométricas não diferiram entre os grupos. Valores superiores de pressão arterial foram observados no grupo D/MORF em relação ao D/ SAL dos 75 aos 120 minutos. Conclui-se que os três tratamentos determinaram discretas alterações nos parâmetros cardiorrespiratórios, além de efeito sedativo. Contudo, a adição dos opioides à detomidina não incrementou o grau de sedação em cavalos submetidos aos estímulos na cavidade oral

Outstanding Indoor Performance of Perovskite Photovoltaic Cells - Effect of Device Architectures and Interlayers

Indoor photovoltaics is one of the best sustainable and reliable energy source for low power consumption electronics such as the rapidly growing Internet of Things. Perovskite photovoltaic (PPV) cells with three benchmark device architectures – mesoporous PPV (mPPV) and inverted PPV (iPPV) with alternative hole transporting layers (HTLs), and carbon‐based PPV (cPPV) are studied under a simulated indoor environment. The mPPV cell using typical Spiro‐OMeTAD as the HTL shows the highest maximum power density (Pmax) of 19.9 μW cm−2 under 200 lux and 115.6 μW cm−2 under 1000 lux (without masking), which is among the best of the indoor PV. Interestingly, when PTAA is used as the HTL in the mPPV cell, the Pmax drops to almost zero under indoor light environment while its performance under one sun remains similar. On the other hand, when PEDOT:PSS is replaced by Poly‐TPD as HTL in the iPPV cell, the Pmax under indoor light improves significantly and is comparable to that of the best mPPV cell. This significant difference in indoor performance correlates well with their leakage current. The HTL‐free cPPV cell, prepared by fully up‐scalable techniques, shows a promising Pmax of 16.3 and 89.4 μW cm−2 under 200 and 1000 lux, respectively. A practical scale 5 × 5cm2 cPPV module is fabricated as a demonstration for real applications