Oil palm monoculture comprises one of the most financially attractive land-use options in tropical forests, but cropland suitability overlaps the distribution of many highly threatened vertebrate ...species. We investigated how forest mammals respond to a landscape mosaic, including mature oil palm plantations and primary forest patches in Eastern Amazonia. Using both line-transect censuses (LTC) and camera-trapping (CT), we quantified the general patterns of mammal community structure and attempted to identify both species life-history traits and the environmental and spatial covariates that govern species intolerance to oil palm monoculture. Considering mammal species richness, abundance, and species composition, oil palm plantations were consistently depauperate compared to the adjacent primary forest, but responses differed between functional groups. The degree of forest habitat dependency was a leading trait, determining compositional dissimilarities across habitats. Considering both the LTC and CT data, distance from the forest-plantation interface had a significant effect on mammal assemblages within each habitat type. Approximately 87% of all species detected within oil palm were never farther than 1300 m from the forest edge. Our study clearly reinforces the notion that conventional oil palm plantations are extremely hostile to native tropical forest biodiversity, which does not bode well given prospects for oil palm expansion in both aging and new Amazonian deforestation frontiers.
Nitric oxide (NO) donors are substances that can release NO. Vascular relaxation induction is among the several functions of NO, and the administration of NO donors is a pharmacological alternative ...to treat hypertension. This review will focus on the physicochemical description of ruthenium-derived NO donor complexes that release NO via reduction and light stimulation. In particular, we will discuss the complexes synthesized by our research group over the last ten years, and we will focus on the vasodilation and arterial pressure control elicited by these complexes. Soluble guanylyl cyclase (sGC) and potassium channels are the main targets of the NO species released from the inorganic compounds. We will consider the importance of the chemical structure of the ruthenium complexes and their vascular effects.
Carbon dots (CDs) are nanometer-scale particles produced from carbon sources that exhibit fluorescence emission. The present work presents the synthesis and characterization of CDs, as well as the ...sensing studies for the determination of chloramphenicol (CAP). CAP is an antibiotic used in human medicine and agriculture, and its indiscriminate use and inappropriate disposal have caused damage to human health and the environment. The carbonaceous precursor used in the synthesis of CDs was 3,4-diaminobenzoic acid (3,4-DABA) through the hydrothermal method via domestic microwave irradiation. The first synthesis procedure was carried out in the presence of water/ethanol (a-CDs) and the second in the presence of 1 mol/L sodium hydroxide/ethanol (b-CDs). The CDs were initially characterized in terms of spectroscopic properties in the ultraviolet and visible region (UV-visible), Fourier-transform infrared (FTIR) spectra, Raman spectroscopy, and fluorescence emission spectroscopy. Sensing studies for the antibiotic C were performed by fluorescence suppression in the presence of a- and b-CDs, as well as the precursor 3,4-DABA. The a- and b-CDs presented similar values of linear range 0.00080-0.0050 mg/ml and limit of detection (LOD) = 0.00030 mg/ml (0.30 ppm) for CAP. Then, a- and b-CDs were embedded in Whatman and Mellita® filter paper, and CAP sensing was evaluated through UV light excitation.
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•ZnO nanoparticles were obtained directly on reduced graphene oxide sheets.•rGO promoted electron transport and the reduction of charge carriers recombination.•Nanocomposites show ...lower onset potential than the requirement for H2O oxidation.•The resulting nanocomposites exhibited high current density during electrolysis.•The overpotential for water oxidation decreased in alkaline pH.
Reduced graphene oxide-zinc oxide (rGO-ZnO) nanocomposites were successfully synthesized using a facile microwave-hydrothermal method under mild conditions, and their electrocatalytic properties towards O2 evolution were investigated. The microwave radiation played an important role in obtainment of well dispersed ZnO nanoparticles directly on reduced graphene oxide sheets without any additional reducing reagents or passivation agent. X-ray diffraction (XRD), Raman and infrared spectroscopies indicated the reduction of GO as well as the successful synthesis of rGO-ZnO nanocomposites. The chemical states of the samples were shown by XPS analyses. Due to the synergic effect, the resulting nanocomposites exhibited high electronic interaction between ZnO and rGO sheets, which improved the electrocatalytic oxidation of water with low onset potential of 0.48V (vs. Ag/AgCl) in neutral pH and long-term stability, with high current density during electrolysis. The overpotential for water oxidation decreased in alkaline pH, suggesting useful insight on the catalytic mechanism for O2 evolution.
The anti-malarials quinine and artemisinin were isolated from traditionally used plants (Cinchona spp. and Artemisia annua, respectively). The synthetic quinoline anti-malarials (e.g. chloroquine) ...and semi-synthetic artemisinin derivatives (e.g. artesunate) were developed based on these natural products. Malaria is endemic to the Amazon region where Plasmodium falciparum and Plasmodium vivax drug-resistance is of concern. There is an urgent need for new anti-malarials. Traditionally used Amazonian plants may provide new treatments for drug-resistant P. vivax and P. falciparum. Herein, the in vitro and in vivo antiplasmodial activity and cytotoxicity of medicinal plant extracts were investigated.
Sixty-nine extracts from 11 plant species were prepared and screened for in vitro activity against P. falciparum K1 strain and for cytotoxicity against human fibroblasts and two melanoma cell lines. Median inhibitory concentrations (IC50) were established against chloroquine-resistant P. falciparum W2 clone using monoclonal anti-HRPII (histidine-rich protein II) antibodies in an enzyme-linked immunosorbent assay. Extracts were evaluated for toxicity against murine macrophages (IC50) and selectivity indices (SI) were determined. Three extracts were also evaluated orally in Plasmodium berghei-infected mice.
High in vitro antiplasmodial activity (IC50 = 6.4-9.9 µg/mL) was observed for Andropogon leucostachyus aerial part methanol extracts, Croton cajucara red variety leaf chloroform extracts, Miconia nervosa leaf methanol extracts, and Xylopia amazonica leaf chloroform and branch ethanol extracts. Paullinia cupana branch chloroform extracts and Croton cajucara red variety leaf ethanol extracts were toxic to fibroblasts and or melanoma cells. Xylopia amazonica branch ethanol extracts and Zanthoxylum djalma-batistae branch chloroform extracts were toxic to macrophages (IC50 = 6.9 and 24.7 µg/mL, respectively). Andropogon leucostachyus extracts were the most selective (SI >28.2) and the most active in vivo (at doses of 250 mg/kg, 71% suppression of P. berghei parasitaemia versus untreated controls).
Ethnobotanical or ethnopharmacological reports describe the anti-malarial use of these plants or the antiplasmodial activity of congeneric species. No antiplasmodial activity has been demonstrated previously for the extracts of these plants. Seven plants exhibit in vivo and or in vitro anti-malarial potential. Future work should aim to discover the anti-malarial substances present.
The present work reports the one-step synthesis of reduced graphene oxide (rGO)–TiO2 nanocomposites using a microwave-assisted hydrothermal method. The well-dispersed TiO2 nanoparticles on rGO sheets ...were obtained without a reducing agent. X-ray diffraction, Raman and infrared spectroscopies indicated the reduction of graphene oxide (GO) under microwave conditions, and the microscopy images revealed the successful formation of nanocomposites. In addition, double band gap values (Egap = 2.39 and 3.37 eV) for the 16rGO–TiO2 nanocomposite were observed. The heterostructure presented a higher electrocatalytic performance for water oxidation under neutral and alkaline conditions, when compared to pure TiO2 nanoparticles, and long-term current stability. The electrochemical characterization showed that the rGO–TiO2 nanocomposites presented efficient charge separation, as demonstrated by photoluminescence spectra, which was related to the high electronic transfer between TiO2 nanoparticles and rGO sheets. This work provided new insights into the development of high performance and cost-effective rGO–TiO2 electrocatalysts for the oxygen evolution reaction.
Vocal activity and signal characteristics of mammals are driven by several factors that result in both stability and plasticity over multiple time scales. All three extant species of manatee ...communicate with several calls that are especially important for maintaining contact between cows and calves. Determining if calf calls differ across manatee species will provide insights into the evolution of species-specific acoustic communication traits. We investigated the interspecific differences in the vocalizations of calves of Amazonian manatees (Trichechus inunguis) and the two subspecies of the West Indian manatee (T. manatus). Vocalizations of individual calves were recorded in rehabilitation centers in Brazil, Puerto Rico, the United States, and Mexico. The acoustic structure of calls produced by manatee calves varied between species and with body size. Amazonian manatee calves produced shorter calls with multiple notes at higher frequency while West Indian calves produced modulated calls that were lower in frequency and longer in duration. Smaller West Indian calves produced frequency modulated, hill-shaped calls that flattened with an increase in body length. Our results provide evidence for divergence in the ontogeny of vocalizations across T. manatus and T. inunguis and suggest variation in body size contributed to the evolution of differences in the characteristics of their calls.
The nanoencapsulation of botanical compounds (such as geraniol) is an important strategy that can be used to increase the stability and efficiency of these substances in integrated pest management. ...In this study, chitosan/gum arabic nanoparticles containing geraniol were prepared and characterized. In addition, evaluation was made of the biological activity of geraniol encapsulated in chitosan/gum arabic nanoparticles toward whitefly (Bemisia tabaci). The optimized formulation showed a high encapsulation efficiency (>90%) and remained stable for about 120 days. The formulation protected the geraniol against degradation by UV radiation, and the in vitro release was according to a diffusion mechanism that was influenced by temperature. An attraction effect was observed for Bemisia tabaci, indicating the potential of this type of system for use in pest management, especially in trap devices.
Metal hexacyanoferrates (HCF), which are produced by hydrothermal synthesis, have received increasing attention for different applications due to their unique physicochemical properties, such as ...three-dimensional framework with large open sites and metal sites with different oxidation states. The hydrothermal method is a simple and established synthesis technique, with the ability to synthesize unstable materials near the melting point, the possibility to synthesize large and good quality crystals and to obtain tunable size particles, controlled agglomeration, and low contamination by impurities, and in which the properties of products depend on the formation mechanism and hydrothermal conditions. Focusing on the structure of HCF including crystallography and morphology from the literature, this review discusses the effects of synthesis conditions (metal precursor, hydrothermal temperature, and duration) and post-treatment (acid addition and calcination) on the formation of metal hexacyanoferrates. Furthermore, structural modifications and current progress toward the application of HCF as catalysts, sensors, adsorbents, electrochromic displays, and energy storage are also summarized in this review.
Abstract Objectives The aim of the present study was to evaluate the effect of açai pulp ( Euterpe oleracea Martius) intake on the prevention of oxidative damage by measuring the activity of ...antioxidant enzymes and biomarkers of protein oxidation in women. Methods A nutritional intervention study was conducted with thirty-five healthy women who were asked to consume 200 g/d of açai pulp for 4 wk. Blood samples were collected, and blood pressure and anthropometric parameters were measured before and after the experimental period. Antioxidant enzymes, superoxide dismutase, catalase, glutathione, production of reactive oxygen species, and total antioxidant capacity were evaluated in polymorphonuclear cells. Serum concentration of protein carbonyl and sulfhydryl groups were also determined. Results The açai intake increased catalase activity, total antioxidant capacity, and reduced the production of reactive oxygen species. Furthermore, it reduced serum concentration of protein carbonyl and increased total serum sulfhydryl groups. Conclusions These results show the antioxidant benefit of dietary açai for the healthy women included in the present study, and may increase understanding of the beneficial health properties of this fruit.
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