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1,272 result(s) for "Silva, Fernando Carvalho"
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Development of a Method for the Quantification of Clotrimazole and Itraconazole and Study of Their Stability in a New Microemulsion for the Treatment of Sporotrichosis
Sporotrichosis occurs worldwide and is caused by the fungus Sporothrix brasiliensis. This agent has a high zoonotic potential and is transmitted mainly by bites and scratches from infected felines. A new association between the drugs clotrimazole and itraconazole is shown to be effective against S. brasiliensis yeasts. This association was formulated as a microemulsion containing benzyl alcohol as oil, Tween® 60 and propylene glycol as surfactant and cosurfactant, respectively, and water. Initially, the compatibility between clotrimazole and itraconazole was studied using differential scanning calorimetry (DSC), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR), and X-ray powder diffraction (PXRD). Additionally, a simple and efficient analytical HPLC method was developed to simultaneously determine the concentration of clotrimazole and itraconazole in the novel microemulsion. The developed method proved to be efficient, robust, and reproducible for both components of the microemulsion. We also performed an accelerated stability study of this formulation, and the developed analytical method was applied to monitor the content of active ingredients. Interestingly, these investigations led to the detection of a known clotrimazole degradation product whose structure was confirmed using NMR and HRMS, as well as a possible interaction between itraconazole and benzyl alcohol.
Succession of medico-legal important flesh flies (Diptera: Sarcophagidae) in the temporal gradient of pig decomposition in the Brazilian Cerrado
Flies belonging to the Sarcophagidae family play a significant role in forensic investigations by aiding in the estimation of post-mortem interval through the assessment of the developmental time of their immature stages and/or the succession patterns of species on carcasses and cadavers. In this regard, this study aimed to investigate the ecological succession of these flies on pig carcasses within Cerrado of Brazil. The progression of fly succession was examined over a 10-day period using the Threshold Indicator Taxa Analysis (TITAN) approach. Six Z + species ( Oxysarcodexia thornax (Walker), Peckia ( Sarcodexia ) lambens (Wiedemann), Peckia ( Euboettcheria ) collusor (Curran & Walley), Ravinia belforti (Prado & Fonseca), Tricharaea ( Sarcophagula ) canuta (Wulp) and Tricharaea ( Sarcophagula ) occidua (Fabricius)) were identified, with change points ranging from 2.5 to 3 days during the dry season and 2.5 to 5.5 days during the rainy season. Two Z−  species ( Dexosarcophaga carvalhoi (Lopes) and Peckia ( Sarcodexia ) tridentata (Hall)) were present, with a change point of 6.5 days during the rainy season. This study provides a continuous analysis of the temporal succession of flies, enabling an investigation into species progression based on their change points and directions (Z + and Z− ), thereby offering methodological advancements to avoid the arbitrary categorization of inherently continuous data.
Ecological succession of blow flies (Diptera: Calliphoridae) in the decomposition of pig carcasses in Cerrado areas of Brazil
This research aims to describe the process of ecological succession by associating the decomposition stages of pig carcasses with flies from the Calliphoridae family (Diptera). For this, 6 pig carcasses were exposed in Maranhão's Cerrado, utilizing metal cages with sawdust trays to catch immature specimens and “suspended traps” to capture adults. Adults of the Hemilucilia benoisti Séguy, and Hemilucilia townsendi Shannon species were only associated with the swelling stage. Chrysomya megacephala (Fabricius) was associated with 2 stages (black putrefaction and fermentation). The species Chloroprocta idioidea (Robineau-Desvoidy), Chrysomya albiceps (Wiedemann), Cochliomyia macellaria (Fabricius), and Lucilia eximia (Wiedemann) were associated with 4 of the 5 stages of decomposition, the latter being the only 1 associated with the initial stage. The larvae abandoned the carcasses to pupate from the second stage of decomposition, with L. eximia being the only 1 leaving the carcasses in the swelling stage, and C. albiceps the only 1 associated with both the fermentation and dry stages. Our findings indicate that calliphorid species can help forensic investigators estimine the postmortem interval of cadavers in situations similar to those detailed in this study. Since there was a link between adult and immature species and certain stages, they can be used as indicators in future forensic investigations.
Evaluating the Effects of Different Vegetation Types on Necrophagous Fly Communities (Diptera: Calliphoridae; Sarcophagidae): Implications for Conservation
The present study was conducted in five different phytogeographic zones of the Brazilian state of Maranhão, three of which (the Amazon Forest, Cerrado, and Palm Groves) are more heterogeneous, whereas the other two (Marshlands and Mangroves) are more homogeneous. In each zone, nine sites were visited for the collection of necrophagous flies using bait traps in 2010, 2011, and 2012. The calliphorid and sarcophagid communities observed at each site were compared in terms of species richness, composition, and abundance. The more heterogeneous zones had higher species richness, except in the case of the sarcophagids in the forest habitats. The calliphorids Chloroprocta idioidea (Robineau- Desvoidy, 1830), Mesembrinella bicolor (Fabricius, 1805), Hemilucilia semidiaphana (Rondani, 1850) and Lucilia eximia (Wiedemann, 1819) were more closely associated with the Cerrado, Palm Grove and Amazon Forest zones, and Chrysomya megacephala (Fabricius, 194) with the Mangrove. In the sarcophagids, Peckia (Euboettcheria) subducta (Lopes, 1935) and P. (Pattonella) palidipilosa (Curran & Walley, 1934) were associated with the Amazon Forest, and P. (Sarcodexia) lambens (Wiedemann, 1830) and Tricharaea (Sarcophagula) occidua (Fabricius, 1794) with the Palm Grove and Cerrado zones. In the calliphorids, the greatest dissimilarity was recorded between the Amazon Forest and the Mangrove and Lowland grassland zones. In the sarcophagids, by contrast, the greatest dissimilarities were recorded between the Amazon Forest and all the other four zones. In general, then, the phytogeographic zones with the highest environmental heterogeneity were characterized by the greatest species richness and abundance of necrophagous flies.
Drying kinetics of Bixa orellana Labil (annatto) leaves and the influence of temperature on the physicochemical and biological properties of its essential oil
Bixa orellana L. is widely used as a dye, and other properties are still little studied, especially in relation to leaves. This article evaluates how drying B. orellana L. influences the properties of essential oils (EOs) extracted from their leaves. The collected plant material was submitted to convective air-drying oven at temperatures of 35, 45 and 55 °C. Chemical profiles were determined by Gas Chromatography-Mass Spectrometry (GC-MS). Mathematical models were applied to represent the drying process and statistical analysis performed using Statistica 10 software. The EO's were obtained through the hydrodistillation technique with verification of physicochemical properties and antimicrobial activity by the Disc Diffusion Method. For the toxicity test, the bioassay was applied to Artemia salina. Through the results obtained it was possible to determine that the mathematical model of Verma was the one that best fitted the experimental data. Significant differences in the properties of EO's were observed. The temperature of 45 °C allowed obtaining the best EO yield, still presenting the most efficient antimicrobial activity. This study states through the activities analyzed that the drying temperature influences the physicochemical and biological properties of the EO's, thus requiring studies such as this one that evaluate the best mathematical model to predict drying as well as the specific temperatures that influence the properties of the product obtained.
Interdigitated Electrode for Electrical Characterization of Commercial Pseudo-Binary Biodiesel–Diesel Blends
Non-standard diesel blends can be harmful to the environment and human health. In this context, a simple analytical method to estimate the biodiesel mixture ratio in diesel was developed based on impedance spectroscopy (IS) associated with interdigitated sensors. In this article, four different interdigitated sensors with varied comb spacing (G) were simulated using the COMSOL Multiphysics software. Based on finite element simulations, four interdigitated electrode architectures were manufactured and evaluated. The best geometry was chosen according to theoretical data simulations, and its interdigitated electrodes were manufactured for the compositional evaluation of pseudo-binary biodiesel–diesel mixtures. According to the X-ray powder diffraction technique, the deposition of the conductive layer (Au0) over the surface of the dielectric substrate (SiO2) did not alter its phase composition. In the analysis of AFM and SEM, it was possible to observe irregular edges on the electrodes, possibly related to the manufacturing process of the thin layers and mechanical stability. Another characteristic observed in the AFM images was the height of the step of the gold layer of the sensor. Several cross sections were obtained, and the mean step value was 225.71 ± 0.0032 nm. Although there were differences in the roughness, the whole sensor had nanometric roughness. Based on the finite element method simulation performed, it can be assumed that the geometric parameters more suitable for the manufacturing of the electrode are W = 20 µm, L = 1000 µm, G = 50 µm, and N = 40 digits. The electrical characterization performed by impedance spectroscopy showed that we could differentiate between biodiesel and diesel fuels and their pseudo-binary mixtures in the low-frequency region.
The effects of cattle ranching on the communities of necrophagous flies (Diptera: Calliphoridae, Mesembrinellidae and Sarcophagidae) in Northeastern Brazil
Most of the ongoing decline in biodiversity, worldwide, is due to human activities, in particular, the expansion of agriculture. In this context, we highlight the need for studies of the taxonomic groups that can provide insights into the dynamics of the ecological communities facing anthropogenic impacts. For this, we evaluated the effects of the environmental changes caused by cattle ranching on five phytophysiognomies (Cerrado Savanna, Amazon Forest, Palm Forest, Marshland, and Mangrove) in the state of Maranhão, Brazil. We tested the hypothesis that the species composition, abundance, and richness of the families Calliphoridae, Mesembrinellidae, and Sarcophagidae (Diptera) are affected by ranching in each of the phytophysiognomies. Specimens were collected at 90 sites, including 45 anthropic sites (cattle ranches) and 45 preserved habitats, using traps baited with bovine lung. We collected 15,023 calliphorids (11 species), 10,772 sarcophagids (52 species), and 241 mesembrinellids (one species). The results indicated significant differences between anthropic and preserved habitats in the species composition, abundance, and richness of sarcophagids, in particular in the Amazon Forest, where the highest species richness was recorded in the anthropic environments. In the case of the calliphorids and mesembrinellids, by contrast, significant differences were found in species composition and abundance in only in four of the five phytophysiognomies analyzed (excluding the Cerrado Savanna), while species richness only varied in the palm forest and marshland. In all cases, lower values were recorded in the anthropic environments. These results indicate that the insects of the families Sarcophagidae, Calliphoridae, and Mesembrinellidae respond differentially to the anthropic activity (cattle ranching) and can be used to evaluate this type of anthropogenic impact systematically. In addition, the Amazon Forest was the phytophysiognomy most impacted by this activity in the Brazilian state of Maranhão.
Necrophagous flies (Diptera: Calliphoridae and Sarcophagidae) as indicators of the conservation or anthropization of environments in eastern Amazonia, Brazil
The present study compared patterns of diversity of the families Calliphoridae and Sarcophagidae (Diptera: Oestroidea) among areas of primary and secondary forest, and clearings in the Amazon biome. We evaluated the relationship between habitat specialist and generalist species, verifying their potential for use as bioindicator species. The study was conducted in 27 areas that comprise primary and secondary forests and clearings in the municipality of Juruti, Pará, Brazil. We collected 4286 necrophagous flies in the three study environments. The hypothesis of dissimilarity in the diversity among environments was corroborated for the Sarcophagidae and partly upheld for the Calliphoridae. The sarcophagid species Oxysarcodexia carvalhoi (Lopes 1946), Oxysarcodexia fringidea (Curran and Walley 1934), Oxysarcodexia thornax (Walker 1849), and the calliphorids Chrysomya megacephala (Fabricius 1794) and Cochliomyia macellaria (Fabricius 1775) were all associated with clearing environments. No sarcophagid species were identified as indicators of primary forest. The calliphorids, Chloroprocta idioidea (Robineau-Desvoidy 1830) and Paralucilia adespota (Dear 1985) were identified as indicators of primary + secondary forest. The occurrence of indicator species and their levels of tolerance varied considerably between the two families. The calliphorids and sarcophagids both included species capable of representing differences in necrophagous fly’s diversity among clearing, primary and secondary forest environments, which increases the understanding of the ecology of the taxa and their potential use for biomonitoring, management, and habitat conservation.Implications for insects conservationIn general, sarcophagids had a strong relationship with clearings and secondary forest. Some species show intense scavenger behavior and preference for altered environments. This reinforces the importance of the relationship between species and landscapes. In calliphorids, only Chloroprocta idioidea was associated with primary and secondary forest. We also recorded calliphorid species that prefer clearings and secondary forest and are highly tolerant to variation from abiotic factors, with wide niche breadth due to preference for these landscape types. The niche breadth and the tolerance shown by the species are an indication of the potential success of these organisms in response to anthropic processes and changes in landscapes.
(3,3’-Methylene)bis-2-hydroxy-1,4-naphthoquinones induce cytotoxicity against DU145 and PC3 cancer cells by inhibiting cell viability and promoting cell cycle arrest
We developed a novel method for the synthesis of bis-naphthoquinones (BNQ), which are hybrids of lawsone (2-hydroxy-1,4-naphthoquinone) and 3-hydroxy-juglone (3,5-dihydroxy-1,4-naphthoquinone). The anticancer activity of three synthesized compounds, named 4 (RC10), 5 (RCDFC), and 6 (RCDOH) was evaluated in vitro against two metastatic prostate cancer (PCa) cell lines, DU145 and PC3, using MTT assays. We found that 4 (RC10) and 5 (RCDFC) induced cytotoxicity against DU145 and PC3 cells. Flow cytometry analysis revealed that these two compounds promoted cell cycle arrest in G1/S and G2/M phases, increased Sub-G1 peak and induced inhibition in cell viability. We also showed that these effects are cell-type context dependent and more selective for these tested PCa cells than for HUVEC non-tumor cells. The two BNQ compounds 4 (RC10) and 5 (RCDFC) displayed promising anticancer activity against the two tested metastatic PCa cell lines, DU145 and PC3. Their effects are mainly associated with inhibition of cell viability, possibly through apoptotic cell death, besides altering the SubG1, G1/S and G2/M phases of cell cycle. 5 (RCDFC) compound was found to be more selective than 4 (RC10), when comparing their cytotoxic effects in relation to HUVEC non-tumoral cells. Future work should also test these compounds in combination with other chemotherapeutic drugs to evaluate their effects on further sensitizing drug-resistant metastatic PCa cells.
Trace metals in estuarine organisms from a port region in southern Brazil: consumption risk to the local population
Metal contamination is a threat to estuarine environments. They can accumulate in the food chain and cause toxic effects on aquatic organisms and human health. This study evaluated the concentrations of metals (Cd, Cr, Cu, Fe, Ni, Pb, and Zn) in aquatic organisms of Antonina Bay (southern Brazil) to analyze whether the metal concentrations were in accordance with Brazilian food legislation and estimate the human risk of local seafood consumption. All analyzed organisms ( Centropomus parallelus , Mugil curema , Genidens genidens , Crassostrea brasiliana , and Xiphopenaeus kroyeri ) showed traces of metals in their tissues with different metal concentrations among species. Metal concentrations were generally higher in oyster C. brasiliana , and biomagnification was not observed. Cr and Zn concentrations were above the limits established by legislation for all species in at least one sample. The concentrations of the other metals were within permitted levels. However, concentrations of Cd, Cr, Fe, and Zn posed a human consumption risk. In general, the C. brasiliana oyster presented the highest risk for human consumption, probably due to its filtering habit. Thus, the results indicated that metal concentrations in the tissues of the Antonina Bay seafood can pose a risk to human health, and this chronic exposure to metals also can cause toxic effects on local aquatic biota.