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31.
Leandro F. Pedrosa William P. de Macedo Antonia C. R. Furtado Guilherme P. Guedes Luiz C. S. Pinheiro Jackson A. L. C. Resende 《合成通讯》2013,43(24):3373-3386
New thieno[2,3-b]pyridine phosphoramidates compounds were synthesized and characterized by infrared; 1H, 13C, and 31P NMR spectroscopy; and high-resolution mass spectrometry. The products were obtained in good yields (64–82%) under mild conditions by nucleophilic aromatic substitution reaction of aminoalkylphosphoramidates over 4-chlorothieno[2,3-b]pyridine-5-carbonitrile. The crystal structures of two compounds were solved by x-ray diffraction and showed a network of intermolecular interactions involving phosphoramidate groups. Druglike properties and toxicity of the new compounds were studied with the help of the software Molinspiration, Osiris, and Toxtree, and were compared with the standard drugs amphotericin B, miltefosine, benznidazole, and nifurtimox. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
32.
Joana Patricia N. Ribeiro Joao A. Lopes 《International journal of environmental analytical chemistry》2013,93(10):701-710
The use of microbial biomass in biosorption is already being studied as a potential alternative to (or combined with) conventional processes, where several algae and microorganisms have already shown promising ability to uptake metals. Cyanobacteria (blue-green algae) are widespread organisms, with specific properties, such as high nutrient removal capacity and tolerance to highly variable conditions which make them well-suited for wastewater and remediation purposes. The main aim of this work was to evaluate the use of a marine cyanobacterium LEANCYA 21 (Synechocystis sp.), collected from the Portuguese southern border, for the removal of selected trace metals when in natural seawater culture medium. It was observed, for the first time, that this particular strain is capable of uptaking Pb, Ni and Zn (at nM levels) from seawater solutions using small amounts of biomass. Uptake values for Pb were up to 90% (0.75 mg g?1 biomass) in 6 h. The specific biosorption curves of Ni and Zn showed that these metals follow a first order kinetics biosorption in batch conditions. Solutions containing multimetals have revealed that Ni uptake is affected by the presence of Pb and Zn. The calculated specific absorption values were high enough to predict a possible application in aquaculture where such low levels of metals may inhibit microalgae growth. 相似文献
33.
34.
Caetano P. Sabino Martha S. Ribeiro Mark Wainwright Carolina dos Anjos Fábio P. Sellera Milena Dropa Nathalia B. Nunes Guilherme T. P. Brancini Gilberto U. L. Braga Victor E. Arana-Chavez Raul O. Freitas Nilton Lincopan Maurício S. Baptista 《Photochemistry and photobiology》2023,99(2):742-750
The unbridled dissemination of multidrug-resistant pathogens is a major threat to global health and urgently demands novel therapeutic alternatives. Antimicrobial photodynamic therapy (aPDT) has been developed as a promising approach to treat localized infections regardless of drug resistance profile or taxonomy. Even though this technique has been known for more than a century, discussions and speculations regarding the biochemical mechanisms of microbial inactivation have never reached a consensus on what is the primary cause of cell death. Since photochemically generated oxidants promote ubiquitous reactions with various biomolecules, researchers simply assumed that all cellular structures are equally damaged. In this study, biochemical, molecular, biological and advanced microscopy techniques were employed to investigate whether protein, membrane or DNA damage correlates better with dose-dependent microbial inactivation kinetics. We showed that although mild membrane permeabilization and late DNA damage occur, no correlation with inactivation kinetics was found. On the other hand, protein degradation was analyzed by three different methods and showed a dose-dependent trend that matches microbial inactivation kinetics. Our results provide a deeper mechanistic understanding of aPDT that can guide the scientific community toward the development of optimized photosensitizing drugs and also rationally propose synergistic combinations with antimicrobial chemotherapy. 相似文献
35.
Reicher Fany Leitner Sirlei C. S. Sierakowski Maria R. Fontana Jose D. Correa Joao B. C. 《Applied biochemistry and biotechnology》1991,28(1):353-361
Stryphnodendron barbatiman (barbatimão) is a native tree that is found throughout the “Cerrados,” a region of Central Brazil. Plant seeds, on water extraction, furnished 28 g% galactomannan (dryweight basis), the monosaccharide composition of which (galactose to mannose ratio, 1.0:1.5) fits in the legume heteromannan group. This seed gum, after Sevag deproteinization, still retained 6 g% of associated protein and had a molecular weight of about 1.8 MD on gel filtration. A high intrinsic viscosity (1300 cP) was observed for the polysaccharide sample obtained after reflux of the crushed seeds in 80% aqueous methanol.
相似文献36.
Brito Ciro José Miarka Bianca García-Pastor Teresa Pérez Diego Ignácio Valenzuela Marins Joao Carlos Bouzas Sillero-Quintana Manuel 《Journal of Thermal Analysis and Calorimetry》2021,145(5):2467-2475
Journal of Thermal Analysis and Calorimetry - This study investigated the thermal skin (Tsk) response of lower limbs in older adults with or without osteoarthritis before and after a concurrent... 相似文献
37.
Reis Thaiene A. Matos Breno N. Lima Eliana M. Chaker Juliano A. Gratieri Tais Cunha-Filho Marcílio S. S. Gelfuso Guilherme M. 《Journal of Thermal Analysis and Calorimetry》2017,128(3):1671-1682
Journal of Thermal Analysis and Calorimetry - The objectives of this study were to verify the viability of the photoinitiating system using curcumin as a photoinitiator and glycerol as a... 相似文献
38.
V. Caldas G. R. Brown R. S. Nohr J. G. MacDonald 《Journal of Polymer Science.Polymer Physics》1996,34(12):2085-2098
The double melting endotherm of spunbonded isotactic polypropylene (iPP) fabrics was investigated by monitoring changes in the solid-state NMR spectrum that result from thermal annealing. The DSC melting thermogram was found to change from a double to a single endotherm at anneal temperatures ≥156°C, with a concomitant increase in percent crystallinity. All of the carbon resonances in the CP/MAS NMR spectrum of the purely crystalline phase of iPP were found to be composed of multiple peaks with relative intensities that depend on anneal temperature. By monitoring the changes in the distribution of intensity among the various peaks of a given resonance, a transition temperature of 156°C was identified. Arguments are presented that this redistribution of intensity within a given carbon resonance characterizes the transformation from the α1 to the α2 monoclinic crystal form. The exothermicity associated with this transformation is responsible for the observation of a double melting endotherm by DSC. The splitting patterns observed in the NMR spectrum are discussed in terms of interlayer distances between layers of isochiral helices and the density of exposed methyls at the contact faces of these interlayers. © 1996 John Wiley & Sons, Inc. 相似文献
39.
Kit Ian Kou Jianyu Ou Joao Morais 《Mathematical Methods in the Applied Sciences》2016,39(10):2722-2736
In the present paper, we generalize the linear canonical transform (LCT) to quaternion‐valued signals, known as the quaternionic LCT (QLCT). Using the properties of the LCT, we establish an uncertainty principle for the two‐sided QLCT. This uncertainty principle prescribes a lower bound on the product of the effective widths of quaternion‐valued signals in the spatial and frequency domains. It is shown that only a Gaussian quaternionic signal minimizes the uncertainty. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
40.
Jose Manuel Corcuera Joao Guerra David Nualart Wim Schoutens 《Applied Mathematics and Optimization》2006,53(3):279-309
In this paper we consider the optimal investment problem in a market where the stock price process is modeled by a geometric
Levy process (taking into account jumps).
Except for the geometric Brownian model and the geometric Poissonian model, the
resulting models are incomplete and there are many equivalent martingale measures.
However, the model can be completed by the so-called power-jump assets. By doing this we allow investment in these new assets
and we can try to maximize the expected utility of these portfolios. As particular cases we obtain the optimal portfolios
based in stocks
and bonds, showing that the new assets are superfluous for certain martingale measures
that depend on the utility function we use. 相似文献