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61.
Débora da Silva Paredes Ana Carolina da R. Lessa Selenobaldo A. C. de Sant’Anna Robert M. Boddey Segundo Urquiaga Bruno J. R. Alves 《Nutrient Cycling in Agroecosystems》2014,98(1):41-55
In Brazilian sugarcane plantations, fertilization with vinasse, supplemented or not with mineral fertilizer, is a common practice. But little is known about the effects of this application on N losses, especially those forms of N which give rise to greenhouse gas emissions. The aim of this study was to quantify N2O and NH3 emissions from soil after vinasse application and urea fertilizer addition and to examine the possible impact adding vinasse before or after urea. Two experiments were conducted under greenhouse conditions and one in the field with treatments of vinasse and urea fertilizer, either alone, or in sequence. The highest proportions of N emitted as N2O were registered in the vinasse treatment, which amounted to 15 % of the N applied in the first greenhouse experiment, and 2.5 % in the field experiment. With respect to the losses by NH3 volatilization, urea was the only treatment where this process was significant. N2O emission from vinasse was 2.5 %, somewhat above the default emission factor of 1 % of the IPCC. N2O emissions from urea were also variable, but emission factors registered were still well below the default IPCC factor for organic residues. The order of addition of urea and vinasse had little effect on NH3 volatilization in the field, but there were evidences it was important for N2O. 相似文献
62.
More than 70 % of women with ovarian cancer are diagnosed with advanced-stage disease, which is initially treated with cytoreductive surgery, and combination chemotherapy with platinum-based compounds. Most patients initially respond to platinum-based therapy, but eventually up to 80 % of this responsive cohort becomes refractory due to the development of platinum resistance. This review discusses current and potential therapeutic approaches that exploit biomaterial-based applications to combat platinum resistance either by enhancing the delivery of platinum-based drugs or prodrugs, delivering other toxic non-platinum-based bioactive factors (by themselves or in combination with platinum-based drugs) or by delivering other bioactive factors that re-sensitize resistant ovarian cancer cells to these drugs. The types of materials that are used, the bioactive factors applied (i.e., drug or gene delivery), and the specific agents that are employed to target these types of cancer cells are discussed. We conclude that the unique attributes of biomaterial-based applications can be further explored toward overcoming platinum-resistant ovarian cancer as monotherapy, or in combination with other treatment strategies. 相似文献
63.
64.
Fuente Silvia A. Zubieta Carolina Ferullo Ricardo M. Belelli Patricia G. 《Topics in Catalysis》2019,62(12-16):908-917
Topics in Catalysis - Using the density functional theory, the mechanism of the water–gas shift reaction has been investigated employing a model catalyst formed by a Au5 cluster supported on... 相似文献
65.
Gredson Keiff Souza Alexandre Diório Gracielle Johann Maria Carolina Sérgi Gomes Armando Mateus Pomini Pedro Augusto Arroyo Nehemias Curvelo Pereira 《Journal of the American Oil Chemists' Society》2019,96(1):51-61
This study investigated the effects of variations in oil contents and fatty-acid composition, density, viscosity, acid values, saponification values, specific oxidative stability, and antioxidant concentration of Acrocomia totai kernel oil during fruit maturation. Fatty acids were quantified using 1H nuclear magnetic resonance (NMR) spectroscopy, gas chromatograph-flame-ionization detector (GC-FID), and Fourier transform Raman (FT-Raman) spectroscopy analyses. The results showed that all physicochemical characteristics and oil composition changed during the ripening stage. The CG-FID analysis showed a reduction in the unsaturated fatty-acid content (from 78.8% to 22.1%), with a proportional increase in the saturated fatty-acid contents (from 21.6% to 77.9%). The difference in the fatty-acid composition was confirmed by analysis of the 1H NMR and FT-Raman spectra. The degree of unsaturation was calculated to determine the oxidative stability of oil. These results suggest that the fruit's maturation contributes to the specific oxidative stability. The antioxidant concentration revealed higher contents of carotenoids in the ripe fruit (0.16 mg of carotenoid per 100 gKERNEL) when compared to the unripe fruit (0.05 mg of carotenoid per 100 gKERNEL). In the total phenolics analysis, there was no change in concentration over ripening time. These results show that kernel oil has physicochemical properties comparable with high-quality commercial vegetable oils, suggesting that it is a promising alternative to conventional vegetable oils. 相似文献
66.
Nathália Maria P. Rocha e Silva Fabíola Carolina G. Almeida Fernanda Cristina P. Rocha e Silva Juliana M. Luna Leonie A. Sarubbo 《Journal of surfactants and detergents》2020,23(6):1111-1123
The use of toxic petroleum-based heavy oils is common in industrial processes. The cleaning of machines, equipment, and other surface covered in these oils is achieved with expensive products that are often also toxic and harmful to both the health of workers and the environment. The present paper proposes the development of a sustainable biodetergent made from plant-based materials. Tests were performed to determine the properties of the biodetergent in terms of its surfactant and emulsifying capacities, stability, toxicity, and the removal of heavy oil from glass plates and metallic surfaces. The formulation was composed of a natural solvent (cottonseed oil), a plant-based surfactant agent (saponin), and two natural stabilizers (carboxymethylcellulose and glycerine). The formulation was stable, nontoxic, and highly efficient, removing 100% of the heavy oil from glass and metallic surfaces. This solution developed in this study could be used in diverse industries with the need to clean machines and parts encrusted with oil and grease as well as the cleaning of floors covered with petroleum-based residues. A preliminary analysis of the economic feasibility of using the detergent was carried out at a Brazilian power plant. Besides the reduction in environmental impact due to the use of a nontoxic, biodegradable product as well as the reduction in health risks to workers associated with toxic cleaning products, this new product can have a considerable impact on the market as an environmentally friendly solution. 相似文献
67.
Peter J. Jervis Carolina Amorim Teresa Pereira Jos A. Martins Paula M. T. Ferreira 《International journal of molecular sciences》2021,22(5)
Supramolecular peptide hydrogels are gaining increased attention, owing to their potential in a variety of biomedical applications. Their physical properties are similar to those of the extracellular matrix (ECM), which is key to their applications in the cell culture of specialized cells, tissue engineering, skin regeneration, and wound healing. The structure of these hydrogels usually consists of a di- or tripeptide capped on the N-terminus with a hydrophobic aromatic group, such as Fmoc or naphthalene. Although these peptide conjugates can offer advantages over other types of gelators such as cross-linked polymers, they usually possess the limitation of being particularly sensitive to proteolysis by endogenous proteases. One of the strategies reported that can overcome this barrier is to use a peptidomimetic strategy, in which natural amino acids are switched for non-proteinogenic analogues, such as D-amino acids, β-amino acids, or dehydroamino acids. Such peptides usually possess much greater resistance to enzymatic hydrolysis. Peptides containing dehydroamino acids, i.e., dehydropeptides, are particularly interesting, as the presence of the double bond also introduces a conformational restraint to the peptide backbone, resulting in (often predictable) changes to the secondary structure of the peptide. This review focuses on peptide hydrogels and related nanostructures, where α,β-didehydro-α-amino acids have been successfully incorporated into the structure of peptide hydrogelators, and the resulting properties are discussed in terms of their potential biomedical applications. Where appropriate, their properties are compared with those of the corresponding peptide hydrogelator composed of canonical amino acids. In a wider context, we consider the presence of dehydroamino acids in natural compounds and medicinally important compounds as well as their limitations, and we consider some of the synthetic strategies for obtaining dehydropeptides. Finally, we consider the future direction for this research area. 相似文献
68.
Monika Bednarczyk Carolina Medina-Montano Frederic Julien Fittler Henner Stege Meike Roskamp Michael Kuske Christian Langer Marco Vahldieck Evelyn Montermann Ingrid Tubbe Nadine Rhrig Andrzej Dzionek Stephan Grabbe Matthias Bros 《International journal of molecular sciences》2021,22(6)
The development of nanocarriers (NC) for biomedical applications has gained large interest due to their potential to co-deliver drugs in a cell-type-targeting manner. However, depending on their surface characteristics, NC accumulate serum factors, termed protein corona, which may affect their cellular binding. We have previously shown that NC coated with carbohydrates to enable biocompatibility triggered the lectin-dependent complement pathway, resulting in enhanced binding to B cells via complement receptor (CR)1/2. Here we show that such NC also engaged all types of splenic leukocytes known to express CR3 at a high rate when NC were pre-incubated with native mouse serum resulting in complement opsonization. By focusing on dendritic cells (DC) as an important antigen-presenting cell type, we show that CR3 was essential for binding/uptake of complement-opsonized NC, whereas CR4, which in mouse is specifically expressed by DC, played no role. Further, a minor B cell subpopulation (B-1), which is important for first-line pathogen responses, and co-expressed CR1/2 and CR3, in general, engaged NC to a much higher extent than normal B cells. Here, we identified CR-1/2 as necessary for binding of complement-opsonized NC, whereas CR3 was dispensable. Interestingly, the binding of complement-opsonized NC to both DC and B-1 cells affected the expression of activation markers. Our findings may have important implications for the design of nano-vaccines against infectious diseases, which codeliver pathogen-specific protein antigen and adjuvant, aimed to induce a broad adaptive cellular and humoral immune response by inducing cytotoxic T lymphocytes that kill infected cells and pathogen-neutralizing antibodies, respectively. Decoration of nano-vaccines either with carbohydrates to trigger complement activation in vivo or with active complement may result in concomitant targeting of DC and B cells and thereby may strongly enhance the extent of dual cellular/humoral immune responses. 相似文献
69.
Tamara Carolina; Timberlake William; Leffel Joseph 《Canadian Metallurgical Quarterly》2010,124(3):302
In two experiments we investigated the extent to which rats (Rattus norvegicus) use an egocentric trajectory and landmarks to locate a goal. In Experiment 1 we trained groups to locate the hidden platform in a water maze with either 1 of 3 or 3 of 3 predictive landmarks, and with either a random or fixed egocentric trajectory. A choice test revealed that regardless of the landmark configuration, rats relied on a directional, egocentric trajectory, when it was available, to locate the platform. In Experiment 2 we found that adding four predictive landmarks following training with a constant egocentric trajectory did not alter rats' initial attention to the trajectory. We conclude that the presence of nonpredictive landmarks in a predictive array did not affect the use of landmarks. With a blocking design, rats used initially an egocentric path, then landmarks. These results add to the notion that animals use available spatial cues sequentially. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
70.
Sorption of propylene and propane in polyurethane membranes containing silver nanoparticles 下载免费PDF全文
Carolina Guedes Fioravante Rezende Cristiano Piacsek Borges Alberto Claudio Habert 《应用聚合物科学杂志》2016,133(4)
The preparation of a facilitated transport membrane of polyurethane (PU) containing silver nanoparticles is reported. The propylene and propane sorption was investigated aiming at the selective separation from C3s mixtures. The silver particles were photogenerated in situ into the polyurethane matrix using UV light radiation and silver triflate (AgCF3SO3) as precursor. The morphological properties of these membranes (PUAg) reveled great dispersion of silver particles, which size was smaller than 110 nm. The propylene solubility in PUAg resulted more than four times superior to the one for the pure PU membrane, revealing the high affinity between silver and propylene. Flory–Huggins theory was more accurate to describe the propylene sorption behavior in PUAg than Henry's model. The ideal solubility selectivity of PUAg membrane resulted 24.4, indicating that there is a good potential for an industrial application aiming at the separation of propylene/propane. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42916. 相似文献