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151.
152.
Janine S. Cardoso‐Rurr Juliana Patro de Paiva Ivan G. Paulino‐Lima Tatiana A.M. de Alencar Claudia A.S. Lage Alvaro C. Leito 《Photochemistry and photobiology》2019,95(2):618-626
Rational use of water is a major challenge for governments and global organizations, with easy and inexpensive interventions being sought by communities that are not supplied with drinking water. In this context, solar disinfection (SODIS) has shown great efficiency for water disinfection. To speed up the process and improve inactivation, we studied the effects of methylene blue (MB) as a photodynamic agent because of its ability to absorb visible light (red wavelength) and generate singlet oxygen as a reactive species, thereby inactivating bacteria and viruses present in water. In this study, samples of clean mineral water were artificially contaminated with Gram‐positive (Staphylococcus epidermidis or Deinococcus radiodurans) or with Gram‐negative strains (Escherichia coli or Salmonella typhimurium) and exposed to traditional SODIS or to MB‐SODIS. A lethal synergistic effect was observed when cultures were illuminated in the presence of MB. The obtained results indicate that bacterial inactivation can be achieved in a much shorter time when using MB associated with SODIS treatment. Therefore, this technique was able to provide safe water for consumption through the inactivation of microorganisms in general, including pathogens and some strains resistant to the traditional SODIS procedure, thus allowing its use in areas usually less exposed to sunlight. 相似文献
153.
Walysson Ferreira de Paiva Ingredy Bastos Braga João Vitor de Assis Sandra Milena Bonilla Castañeda Ángel Gabriel Sathicq Valeria Palermo Gustavo Pablo Romanelli Ricardo Natalino Marcio José da Silva Felipe Terra Martins Gustavo Senra Gonçalves de Carvalho Giovanni Wilson Amarante Sergio Antonio Fernandes 《Tetrahedron》2019,75(27):3740-3750
The application of immobilizing calixarene onto the surface of silica using a sol-gel method, as an efficient heterogeneous catalyst (CX4SO3HSi(n)) for multicomponent Povarov reaction has been described. Catalytic activity of the CX4SO3HSi(n) for the synthesis of julolidines under greener and environmentally benign conditions in simple and efficient method was explored. Notably, only 0.5 mol% of the catalyst is sufficient to catalyze the Povarov solvent-free reaction under microwave-assistance. Besides, this protocol allows the construction of four new C–C bonds and two C–N bonds in a single step. To the best of our knowledge, this consists the first silica support calix[4]arene as a heterogeneous catalyst for multicomponent synthesis of julolidines. 相似文献
154.
Thamiris Franckini Paiva Jssica Bentes Alves Príamo Albuquerque Melo Jos Carlos Pinto 《大分子反应工程》2019,13(6)
Schistosomiasis is a parasitic disease that affects millions of people, especially low‐income people, and is considered a major public health problem in underdeveloped countries. The drug used most often for the treatment of the disease is praziquantel (PZQ), which has a strong and characteristic bitter taste that makes treatment of children inconvenient. For this reason, the present work investigates the development of smart pH‐sensitive polymer microparticles produced through suspension polymerizations to be used as vehicles for the controlled release of praziquantel in the body. The microparticles are produced through copolymerization of methyl methacrylate and the cationic comonomers diethylaminoethyl methacrylate or dimethylaminoethyl methacrylate. The obtained results indicate that microparticles with sizes in the range of 10–1100 µm can be formed successfully, allowing high PZQ encapsulation efficiencies (>80%). Zeta potential analyses and drug release assays confirm the pH‐sensitive responses of the cationic copolymers, leading to effective release of PZQ (around 80% in pH 1.2) in acidic media that simulate the organic fluids present in the stomach. 相似文献
155.
Pedro Modesto Nascimento Menezes Henrique Ribeiro de Oliveira Mariana Coelho Brito Gabriela Olinda de Paiva Luciano Augusto de Almeida Ribeiro Angélica Maria Lucchese 《Natural product research》2019,33(17):2571-2573
Lippia thymoides (‘alecrim-do-mato’ or ‘alecrim-do-campo’) is used in Brazilian folk medicine to treat various illnesses, including diarrhea. This work aimed to evaluate in vitro spasmolytic and in vivo antidiarrheal activities of the L. thymoides essential oil (OOS) and to correlate with the traditional use of this plant. In isolated guinea-pig ileum, OOS presented a concentration-dependent spasmolytic activity in preparations pre-contracted with KCl 40 mM [EC50 = 16.89 (11.56–24.66) μg/mL], and antagonized phasic contractions induced by 1 μM carbachol [IC50 = 42.71 (37.35–48.83) μg/mL] or histamine [IC50 = 32.38 (27.44–38.20) μg/mL]. In mice, OOS at 400 mg/kg reduced intestinal transit, at 200 and 400 mg/kg reduced total stool mass and at 400 mg/kg reduced intestinal fluid accumulation. It was shown that the antidiarrheal effect of OOS is related to the inhibition of smooth muscle contraction and may be due to the presence of major compound β-caryophyllene in this essential oil. 相似文献
156.
If we are given real-valued smooth functions on which are in involution, then, under some mild hypotheses, the subset of where these functions are linearly independent is not simply connected.
157.
The term integral geometry has come to describe two different fields of research: one, geometrical, based on the works of Blaschke, Chern, and Santaló,
and another, analytical, based on the works of Radon, John, Helgason, and Gelfand. In this paper we bridge the gap by showing
that classical integral-geometric formulas such as those of Crofton, Cauchy, and Chern can be easily and systematically obtained
through the study of Radon-type transforms on double fibrations. The methods also allow us to extend these formulas to non-homogeneous
settings where group-theoretic techniques are no longer useful. To illustrate this point, we construct all Finsler metrics
on projective space such that hyperplanes are area-minimizing and extend the theory of Crofton densities developed by Busemann,
Pogorelov, Gelfand, and Smirnov.
Pensar es olvidar diferencias. . . Jorge Luis Borges相似文献
158.
Renan Borsoi Campos Fernando Wypych Harley Paiva Martins Filho 《International journal of quantum chemistry》2011,111(9):2137-2148
Calculations at PM3 and PBE/6‐31G levels of part of the IR spectrum of the formamide‐kaolinite intercalatation compound based on a 110‐atom cluster of kaolinite with one formamide molecule are reported. Frequencies and intensities for the formamide vibrations and stretchings of four cluster hydroxyls were calculated through partial hessian matrices and polar tensors obtained by numerical differentiation of energy gradients and dipole moment. The formamide molecule attaches to the kaolinite inner surfaces in multiple conformations with its CN bond vector parallel to the surfaces. Hydrogen bonds are formed between the formamide hydrogen atoms (both from NH2 or CH groups) and the siloxane surface and between the formamide oxygen and nitrogen atoms and the aluminol hydroxyls. The general features of the experimental assignment of the spectrum are confirmed, but the observed splitting of formamide bands is attributed to vibrations from differently attached molecules. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献
159.
Helane?MS?Costa Augusto?CV?Freitas Júnior Ian?PG?Amaral Izaura?Y?Hirata Patrícia?MG?Paiva Luiz?B?CarvalhoJr Vitor?Oliveira Ranilson?S?BezerraEmail author 《Chemistry Central journal》2013,7(1):166
Background
Over the past decades, the economic development and world population growth has led to increased for food demand. Increasing the fish production is considered one of the alternatives to meet the increased food demand, but the processing of fish leads to by-products such as skin, bones and viscera, a source of environmental contamination. Fish viscera have been reported as an important source of digestive proteases with interesting characteristics for biotechnological processes. Thus, the aim of this study was to purify and to characterize a trypsin from the processing by-products of crevalle jack (Caranx hippos) fish.Results
A 27.5 kDa trypsin with N-terminal amino acid sequence IVGGFECTPHVFAYQ was easily purified from the pyloric caeca of the crevalle jack. Its physicochemical and kinetic properties were evaluated using N-α-benzoyl-DL-arginine-p-nitroanilide (BApNA) as substrate. In addition, the effects of various metal ions and specific protease inhibitors on trypsin activity were determined. Optimum pH and temperature were 8.0 and 50°C, respectively. After incubation at 50°C for 30 min the enzyme lost only 20% of its activity. K m , kcat, and k cat /K m values using BApNA as substrate were 0.689 mM, 6.9 s-1, and 10 s-1 mM-1, respectively. High inhibition of trypsin activity was observed after incubation with Cd2+, Al3+, Zn2+, Cu2+, Pb2+, and Hg2+ at 1 mM, revealing high sensitivity of the enzyme to metal ions.Conclusions
Extraction of a thermostable trypsin from by-products of the fishery industry confirms the potential of these materials as an alternative source of these biomolecules. Furthermore, the results suggest that this trypsin-like enzyme presents interesting biotechnological properties for industrial applications.160.
E. Andrade M. J. Madruga I. Bobos M. I. Paiva F. Maia A. Mateus R. Trindade M. C. Freitas M. A. Gonçalves 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(3):777-783
This paper describes the development of a separation method for americium from the effluents emanating from anion exchange
column, used for the recovery of plutonium from analytical waste solutions. The waste contained uranium, sodium, calcium and
iron as the major impurities as estimated by ICP-AES method. ~99% pure americium was obtained by three separation steps using
solvent extraction and extraction chromatography techniques. In the first step, uranium was quantitatively separated by giving
five contacts of equal volumes of 30% TBP in n-dodecane. Fe and Na were separated in the next step using 0.1 M TODGA + 0.5 M DHOA as the extractant. In the last step, Am
was separated from the co-extracted Ca (about 76%) using CMPO loaded extraction chromatographic column. The overall recovery
was >80% with decontamination factor (D.F.) from the impurities being >3000 while the purity of the product was 99%. 相似文献