Electrospun progesterone-loaded cellulose acetate nanofibers and their drug sustained-release profiles

Novel cellulose acetate (CA) nanofibers incorporated with hormone progesterone (P₄) were prepared by electrospinning and its potential as a controlled release system for medicine and veterinary was evaluated by controlled release essay. The morphology, thermal behavior, and structure of P₄-loaded CA nanofibers were characterized by scanning electron microscopy, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The analyses revealed that the incorporation of P₄ increased nanofibers' diameter from around 340 to 892 nm to 8% w/w P₄-loaded CA nanofibers. Furthermore, P₄ has demonstrated high interaction with CA affecting its crystalline structure, since pure CA nanofibers presented 67.23% of crystallinity while P₄-loaded CA nanofibers where amorphous. Ultimately, the drug release essay demonstrated a two-stage profile, and regarding release kinetics, the samples evidenced a diffusion mechanism depending on P₄ concentration in the nanofiber.     

Dyeing plants screening: an approach to combine past heritage and present development

The paper reports an investigation of the colouring properties of 43 dyeing plants chosen for their widespread use in previous centuries. Colorimetric analysis showed that the principal colours on different fabric supports were yellow and mostly unsaturated. The nature of the support fibres investigated, protein- or cellulose-based, was shown to play an important role in the perceived colours. Phytochemical analysis confirmed that yellow-orange shades could be attributed to flavonoids and that red colours were due to anthraquinones. Colours from plants that contain anthocyanins varied from blue-violet through reddish depending on the structure of the anthocyanins in the individual plants. Colour fastness was determined by applying standard test methods. Fastness to light appeared to be inadequate for industrial applications for most samples, but it seems that this could be improved by certain molecular associations. On the other hand, colour fastness to water was satisfactory.     

Polyprenylated benzophenone-enriched extracts obtained using SC–CO2 from the dry ethanolic extract of Brazilian red propolis

Red propolis is a well-known potent antimicrobial source because of its various bioactive compounds. This work aims to submit a sample of Brazilian red propolis to supercritical CO₂ extraction, with subsequent chemical characterisation by HPLC and UHPLC–MS, and to evaluate the antifungal activity against three strains of Candida glabrata. The method proved to be selective for the extraction of benzophenones. The results demonstrated a correlation between the presence of benzophenones and antifungal activity. The supercritical extract that seems to be the richest in benzophenones was the one obtained with a pressure of 300 bar and was the most active against the C. glabrata strains.

Abbreviations: SFE, Supercritical Fluid Extraction; MIC, Minimal Inhibitory Concentration; SC, Supercritical; BZP, benzophenones     

Structural Stability and Optical Studies of Poly(3-hexylthiophene) in an ITO/PEDOT:PSS/P3HT Interface

An interface between poly(3-hexylthiophene) (P3HT) and poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) was prepared in LiClO_4-–acetonitrile (ACN) over indium-doped tin oxide (ITO), known as the ITO/PEDOT:PSS/P3HT system. This system was compared with ITO/P3HT with the aim of studying the stability of aromatic, quinone, and semiquinone segments in the polymer matrix and also elucidating the influence of the structure on the efficiency of organic photovoltaic cells (OPVs). Initially, Raman spectroscopy was used, varying the laser power to verify the destabilization of radical cation segments to dication segments in the ITO/P3HT system. Electrochemical impedance spectroscopy (EIS) was used to show the behavior of the charged species and the charge-transfer processes of the different P3HT segments as a function of time since preparation of the studied systems. In addition, photoluminescence (PL) and time-resolved PL spectroscopy showed the optical properties of the interfaces formed, based on the different quantities of segments present. It was possible to conclude that the modification introduced into the interface by PEDOT:PSS favors stabilization of the P3HT radical cation segment, which remains stable in this interface for lengthy periods (240 h). This should in turn boost hole extraction, increasing OPV efficiency.     

Seasonal characterization and discrimination of savannah physiognomies in Brazil using hyperspectral metrics from Hyperion/EO-1

The seasonal characterization and discrimination of savannahs in Brazil are still challenging due to the high spatial variability of the vegetation cover and the spectral similarity between some physiognomies. As a preparatory study for future hyperspectral missions that will operate with large swath width and better signal-to-noise ratio than the current orbital sensors, we evaluated six Hyperion images acquired over the Estação Ecológica de Águas Emendadas, a protected area in central Brazil. We studied the seasonal variations in spectral response of the savannah physiognomies and tested their discrimination in the rainy and dry seasons using distinct sets of hyperspectral metrics. Floristic and structural attributes were inventoried in the field. We considered three sets of metrics in the data analysis: the reflectance of 146 Hyperion bands, 22 narrowband vegetation indices (VIs), and 24 absorption band parameters. The VIs were selected to represent vegetation structure, biochemistry, and physiology. The depth, area, width, and asymmetry of the major absorption bands centred at 680 nm (chlorophyll), 980, and 1200 nm (leaf water) and 1700, 2100, and 2300 nm (lignin-cellulose) were calculated on a per-pixel basis using the continuum removal method. Using feature selection and multiple discriminant analysis (MDA), we tested the discriminatory capability of these metrics and of their combined use for vegetation discrimination in the rainy and dry seasons. The results showed that the spectral modifications with seasonality were stronger with the savannah woodland-grassland gradient represented by decreasing tree height, basal area, tree density and biomass and by increasing canopy openness. We observed a reflectance increase in the red, red edge, and shortwave (SWIR) intervals towards the dry season. In the near-infrared, the reflectance differences between the physiognomies were smaller in the dry season than in the rainy season. From the 22 VIs, the visible atmospherically resistant index (VARI), visible green index (VIg), and normalized difference infrared index (NDII) were the most sensitive indices to water stress and vegetation cover, presenting the largest rates of changes between the rainy (March) and dry (August) seasons in shrub and grassland areas. Absorption band parameters associated with the lignin-cellulose spectral features in the SWIR increased towards the dry season with great amounts of non-photosynthetic vegetation (NPV) in the herbaceous stratum. The opposite was observed for the 680 nm chlorophyll absorption band and the 980 and 1200 nm leaf water features. In general, the number of selected metrics necessary for vegetation discrimination was lower in the dry season than in the rainy season. The best MDA-classification accuracy was obtained in the dry season using nine VIs (79.5%). The combination of different hyperspectral metrics increased the classification accuracy to 81.4% in the rainy season and to 84.2% in the dry season. This combination added a gain higher than 10% for the classification of shrub savannah, open woodland savannah and wooded savannah.     

Role of resistance physical exercise in preventing testicular damage caused by chronic ethanol consumption in UChB rats

Ethanol consumption is associated with spermatogenesis damage and testosterone level alterations. Alcohol remains the most commonly used substance among athletes and sports enthusiasts. This study evaluated whether resistance physical exercise can reduce the testicular damage caused by ethanol exposure. A total of 36 ethanol drinking (UChB) rats were divided into four groups: C (control rats), ETOH (ethanol consumption), ETOH + T (ethanol consumption + physical training), and T (group physical training). The physical training component of the T and ETOH + T groups was based on a resistance training model consisting of four sets of 10 jumps, with an increasing overload of 50–70% of the body weight attached to the chest three times per week. Rats in the ETOH and ETOH +T groups received 10% ethanol. At postnatal day 90, the rats were sacrificed. Blood sample was collected for hormonal analysis, and the testicles were weighed and processed for histopathological, morphometric, and immunohistochemical analyses. The ETOH group showed an increase in testosterone levels. The immunohistochemical of androgen receptor and the absolute weight of the testes were higher in the ETOH and ETOH + T groups, while the ETOH animals showed a decreased weight gain index. The number of abnormal seminiferous tubules increased in the ETOH and T groups compared to those in the control group (C); however, the association with treatment (ETOH + T group) prevented this effect and decreased caspase‐3 production. In conclusion, these findings show that the combination of ethanol consumption and resistance physical exercise can prevent testicular damage in adult UChB rats.     

Modulation of apolipoprotein E-mediated plasma clearance and cell uptake of emulsion particles by cholesteryl ester

Cholesteryl ester, along with triglyceride (TG), is the major core component of plasma lipoproteins. We investigated the effect of core composition on the physical state and metabolic behavior of lipid emulsions, as model particles of lipoproteins. Fluorescence studies using 1,6-diphenylhexatriene analogs showed that although cholesteryl oleate (CO) significantly decreased core mobility, the surface rigidity of phosphatidylcholine (PC) monolayers was independent of core composition. When intravenously injected into rats, the increased amount of core CO tended to retard TG emulsion removal from plasma, and the initial clearance rate was correlated with the amount of apolipoprotein E (apoE) bound from plasma. In addition, PC liposomes with a similar emulsion particle size showed negligible binding of apoE and were cleared at a slower rate compared to all emulsions. Furthermore, the effect of CO on the binding behavior of apoE to the emulsion surface and the emulsion uptake by hepatocytes was assessed in vitro. Replacing core TG with CO was found to decrease the apoE binding capacity to emulsions markedly without changing the binding affinity and thereby to reduce the cell uptake of emulsion particles by HepG2 cells. These results indicate that the physical state of core lipids, which can be modulated by cO content, plays a role in emulsion metabolism through the alteration in apoE binding.