Leishmaniases are infectious diseases caused by an intracellular protozoan in humans by 20 different species of Leishmania among more than 53 species. There are at least twelve million cases of infections worldwide and three hundred and fifty million people are at risk in at least 98 developing countries in Africa, South-East Asia, and the Americas. Only Brazil presented high burden for both visceral leishmaniasis (VL) and cutaneous (CL). Chemotherapy is the main means of dealing with this infection. Nevertheless, only a few effective drugs are available, and each has a particular disadvantage; toxicity and long-term regimens compromise most chemotherapeutic options, which decreases patient compliance and adherence to the treatment and consequently the emergence of drug-resistant strains. Nano drug delivery systems (NanoDDS) can direct antileishmanial drug substances for intracellular localization in macrophage-rich organs such as bone marrow, liver, and spleen. This strategy can improve the therapeutic efficacy and reduce the toxic effects of several antileishmanial drug substances. This review is an effort to comprehensively compile recent findings, with the aim of advancing understanding of the importance of nanotechnology for treating leishmaniases.

No abstract

Few investigations have examined the structural controls of bark on its water storage and influence on stemflow, despite the bark being considered a critical component that determines the time and magnitude of this process. This study seeks to answer the question: Do bark water absorbability and wettability estimates correlate with stemflow yield? We hypothesized that (1) the absorbability and wettability are correlated, that is, greater water absorbability implies greater wettability, and (2) high rates of bark water absorbability and wettability has a strong and negative correlation with stemflow generation. Stemflow yield (Sy) was monitored over 12 months for 31 trees, representing 9 species common to the Brazilian savanna ecosystem known as Cerrado. Bark absorbability, per unit dry weight, changes over time of the water absorbability (BWA - by submersion methodology), bark drying (BWD), bark absorbability rate (BWArate), bark drying rate (BWDrate), and wettability (initial contact angle – CAin and CA rate - CArate) were determined under laboratory conditions. As insoluble lignin may also act to alter bark water storage dynamics, for each species, the bark insoluble lignin content was characterized. Stemflow variability was significant across the study species. Funneling ratios (FR) indicates that all species’ canopies diverted enough rainfall as stemflow to concentrate rainwaters at the surface around their stem bases (FR > 1). Differences in bark water absorbability were notable some of tree species. A decrease in the CA value as a function of time was not observed for all barks, which in association with stemflow yields, allowed a novel classification method of wettability, based on CAin and it’s rate of change: highly wettable (CAin ≤ 75.3° and CArate ≥ 0.26°h–1) and non-wettable (CAin ≥ 93.5° and CArate ≤ 0.13°h–1). So, only from the wettability classification could be observed that the non-wettable bark species presented higher Sy, FR, BWA, and BWArate than highly wettable bark species. The stemflow from species with highly wettable bark had a strong and positive correlation with BWA. On the other hand, non-wettable bark stemflow yield has a strongly and negative correlation with FR, CAin, and BWArate. Thus, bark wettability properties showed to deserves special attention. This novel classification of bark wettability had a substantial effect on stemflow yield comprehension and proved to be an important variable to link laboratory and field investigation for understanding the stemflow yield. These findings will improve our understanding of the stemflow dynamics, water balance and the ecohydrology processes of forest ecosystems.

No abstract

No abstract

Chitosan (Ch) is a polysaccharide obtained from chitin: a renewable, nontoxic, biocompatible biomolecule that constitutes the second most abundant natural polymer on the planet. The presence of amino groups in the chitosan polymer chains allows one to change the physicochemical properties of the natural polymer. In this work, we prepared a chitosan derivative (ChMM) with ethoxymethylenemalononitrile (EMM) through a nucleophilic vinylic substitution (SNV), changing the experimental conditions of stoichiometry, solvent (ethanol, dimethylsulfoxide (DMSO)) and reaction time (3 and 6 h). ChMM was characterized by Fourier transform infrared spectroscopy (FTIR), solid‐state 13C NMR, elemental analysis (EA), thermogravimetry (TG), scanning electron microscopy (SEM) and X‐ray diffraction (XRD). The FTIR and 13C NMR results confirm the success of the reaction, showing a sharp peak at 2213 cm−1 corresponding to the stretching of the C–N bond and additional signals at 52 and 166 ppm, respectively. The degree of substitution (DS) was calculated from EA and the results obtained show that sample modified with a [Ch]/[EMM] molar ratio of 1:2 over 3 h in DMSO presented the better result (DS = 0.91). ChMM did not show a considerable change in morphology (SEM) and thermal stability (TG). The insertion of methylenemalononitrile groups led to a decrease in the crystallinity index of chitosan derivatives (XRD). ChMM showed good ability to remove dyes in acidic and basic media (pH 5, 7, 9), and for crystal violet and safranin dyes the removal percentage surpassed 70%. © 2022 Society of Industrial Chemistry.

No abstract

No abstract