Andressa Maria Aguiar de Carvalho

Bio: Andressa Maria Aguiar de Carvalho is an academic researcher from Federal University of Piauí. The author has contributed to research in topics: Minimum inhibitory concentration & Minimum bactericidal concentration. The author has an hindex of 3, co-authored 5 publications receiving 35 citations. Previous affiliations of Andressa Maria Aguiar de Carvalho include Universal Forest Products.

Synergic effect of simvastatin in combination with amphotericin B against environmental strains of Cryptococcus neoformans from northeastern Brazil: a prospective experimental study.

Abstract: BACKGROUND: Statins are used as cholesterol-lowering drugs and may also have direct antimicrobial effects. OBJECTIVE: To evaluate synergic interactions between simvastatin and both amphotericin B and fluconazole, against environmental strains of Cryptococcus neoformans isolated from captive birds’ droppings. DESIGNAND SETTING: Experimental study conducted at Federal University of Piaui, Parnaiba, in collaboration with Federal University of Triângulo Mineiro, Uberaba, Brazil. METHODS: Statin susceptibility tests of Cryptococcus neoformans samples were performed as prescribed in standards. Interactions of simvastatin with amphotericin and fluconazole were evaluated using the checkerboard microdilution method. Presence of these interactions was quantitatively detected through determining the fractional inhibitory concentration index (FICI). RESULTS: Isolates of Cryptococcus neoformans were obtained from 30 of the 206 samples of dry bird excreta (14.5%) that were collected from pet shops and houses. Ten isolates were selected for susceptibility tests. All of them were susceptible to amphotericin and fluconazole. All presented minimum inhibitory concentration (MIC) > 128 µg/ml and, thus, were resistant in vitro to simvastatin. An in vitro synergic effect was shown through combined testing of amphotericin B and simvastatin, such that six isolates (60%) presented FICI < 0.500. Two isolates showed considerable reductions in MIC, from 1 µg/ml to 0.250 µg/ml. No synergic effect was observed through combining fluconazole and simvastatin. CONCLUSION: These results demonstrate that simvastatin should be considered to be a therapeutic alternative, capable of potentiating the action of amphotericin B. However, further studies are necessary to clarify the real effect of simvastatin as an antifungal agent.

Insurreições femininas: resistências de mulheres quebradeiras de coco babaçu

Abstract: Este estudo tem como objetivo refletir sobre os modos de vida e de luta de mulheres quebradeiras de coco piauienses junto ao Movimento Interestadual de Quebradeiras de Coco Babacu (MIQCB). Tratou-se de um estudo cartografico realizado em tres comunidades da zona rural da cidade de Esperantina, no Piaui, onde esta localizada a sede regional do MIQCB. Para a producao dos dados, utilizamos como recursos a intervencao fotografica e a producao de narrativas de vida. Assim, destacamos, por um lado, as relacoes de poder com os patroes que marcaram as trajetorias de vida das mulheres, produzindo assujeitamento; mas por outro, evidenciamos suas formas de luta. Para isso, utilizamos a nocao de parresia foucaultiana e da amizade como exercicio politico enquanto formas de contraconduta e resistencia as sujeicoes e como modos de reinvencao de si, contribuindo para o fortalecimento da luta.

The Potential of Silver Nanoparticles for Antiviral and Antibacterial Applications: A Mechanism of Action

Abstract: Rapid development of nanotechnology has been in high demand, especially for silver nanoparticles (AgNPs) since they have been proven to be useful in various fields such as medicine, textiles, and household appliances. AgNPs are very important because of their unique physicochemical and antimicrobial properties, with a myriad of activities that are applicable in various fields, including wound care management. This review aimed to elucidate the underlying mechanisms of AgNPs that are responsible for their antiviral properties and their antibacterial activity towards the microorganisms. AgNPs can be synthesized through three different methods—physical, chemical, and biological synthesis—as indicated in this review. The applications and limitations of the AgNPs such as their cytotoxicity towards humans and the environment, will be discussed. Based on the literature search obtained, the properties of AgNPs scrutinizing the antibacterial or antiviral effect shown different interaction towards bacteria which dependent on the synthesis processes followed by the morphological structure of AgNPs.

A Review of Microwave Synthesis of Zinc Oxide Nanomaterials: Reactants, Process Parameters and Morphologies

Abstract: Zinc oxide (ZnO) is a multifunctional material due to its exceptional physicochemical properties and broad usefulness. The special properties resulting from the reduction of the material size from the macro scale to the nano scale has made the application of ZnO nanomaterials (ZnO NMs) more popular in numerous consumer products. In recent years, particular attention has been drawn to the development of various methods of ZnO NMs synthesis, which above all meet the requirements of the green chemistry approach. The application of the microwave heating technology when obtaining ZnO NMs enables the development of new methods of syntheses, which are characterised by, among others, the possibility to control the properties, repeatability, reproducibility, short synthesis duration, low price, purity, and fulfilment of the eco-friendly approach criterion. The dynamic development of materials engineering is the reason why it is necessary to obtain ZnO NMs with strictly defined properties. The present review aims to discuss the state of the art regarding the microwave synthesis of undoped and doped ZnO NMs. The first part of the review presents the properties of ZnO and new applications of ZnO NMs. Subsequently, the properties of microwave heating are discussed and compared with conventional heating and areas of application are presented. The final part of the paper presents reactants, parameters of processes, and the morphology of products, with a division of the microwave synthesis of ZnO NMs into three primary groups, namely hydrothermal, solvothermal, and hybrid methods.

Facile preparation of a novel biogenic silver-loaded Nanofilm with intrinsic anti-bacterial and oxidant scavenging activities for wound healing.

Abstract: To eliminate the microbial infection from an injury site, various modalities have been developed such as dressings and human skin substitutes. However, the high amount of reactive oxygen species, microbial infection, and damaging extracellular matrix remain as the main challenges for the wound healing process. In this study, for the first time, green synthesized silver nanoparticles (AgNPs) using Teucrium polium extract were embedded in poly lactic acid/poly ethylene glycol (PLA/PEG) film to provide absorbable wound dressing, with antioxidant and antibacterial features. The physicochemical analysis demonstrated, production of AgNPs with size approximately 32.2 nm and confirmed the presence of phytoconstituents on their surface. The antibacterial assessments exhibited a concentration-dependent sensitivity of Staphylococcus aureus and Pseudomonas aeruginosa toward biosynthesized AgNPs, which showed a suitable safety profile in human macrophage cells. Furthermore, oxidant scavenging assays demonstrated exploitation of plant extract as a reducing agent, endows antioxidant activity to biogenic AgNPs. The formation of PLA/PEG nanofilm and entrapment of AgNPs into their matrix were clearly confirmed by scanning electron microscopy. More importantly, antibacterial examination demonstrated that the introduction of biogenic AgNPs into PLA/PEG nanofibers led to complete growth inhibition of P. aeruginosa and S. aureus. In summary, the simultaneous antioxidant activity and antimicrobial activity of the novel biogenic AgNPs/PLA/PEG nanofilm showed its potential for application as wound dressing.

Review on green nano-biosynthesis of silver nanoparticles and their biological activities: with an emphasis on medicinal plants

Abstract: Since two decades ago, the concept of green chemistry has been spreading and researchers are developing greener and more sustainable methods for nanoparticles (NPs) production. The main goals are f...