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81.
L. A. Medeiros J. Limaco S. B. Menezes 《Journal of Computational Analysis and Applications》2002,4(3):211-263
Dedicated to Professor Jacque-Louis Lions on the occasion of his 70th birthday
We consider a mixed problem for the operator
in a noncylindrical domain
. We obtain local solution in t. When we add a viscosity we obtain a global solution. We also investigate the asymptotic behavior of the energy. 相似文献
82.
E.M. Baggio-Saitovitch D.R. Sánchez M.B. Fontes S.N. Medeiros 《Hyperfine Interactions》2000,126(1-4):263-268
57Fe Mössbauer spectroscopy has been used to study rare earth intermetallic compounds having strongly correlated electronic properties, where the transition metal carries no magnetic moment. In this case 57Fe is a local probe to detect very small transferred hyperfine fields (B thf) from the rare earth sites. 相似文献
83.
Amanda Carla Quintas de Medeiros Vieira Graziella Silvestre Marques Cybelly Marques de Melo Keyla Emanuelle Ramos da Silva Larissa Araújo Rolim Maria do Carmo Alves de Lima Suely Lins Galdino Ivan da Rocha Pitta Pedro José Rolim Neto 《Journal of Thermal Analysis and Calorimetry》2014,115(3):2339-2349
LPSF/GQ-130 is a drug candidate, according to reports about its significant anti-inflammatory activity and non-toxicity demonstrated in an acute preclinical study. Despite this, knowledge of its physical–chemical properties is insufficient for the development of medicines. Thus, this work aimed to characterize the raw material at its molecular, particle, and agglomerate level as well as evaluate its thermal compatibility to pharmaceutical excipients. Through spectrometric techniques the molecular structure of the substance was confirmed. For thermal analysis its melting (171.3–176.5 °C) and degradation (238.3–297.4 °C) ranges, besides its purity (99.37 %), were determined. The kinetic non-isothermal degradation supplied the order of thermal reaction (0), the activation energy (96.14 kJ mol?1) and the frequency factor (3.130 × 10?7 min?1). The diffraction of X-rays presented well defined signs in the angles 5.5°, 16.3°, and 44.18° 2θ, suggesting crystalline structure. Scanning electronic microscopy exhibited needle morphology. LPSF/GQ-130 presented Type-III isotherm adsorption/desorption, with a superficial area of 81.3529 m2 g?1 and water content calculated at 1 % using the Karl Fisher method. Laser granulometry calculated its granulometry between 11.65 and 13.10 μm, thus it was characterized as a very fine powder. The prototype was classified as insoluble in water (<0.0187 μg mL?1) and soluble in acetone and acetonitrile, and exhibits instability in basic pH (100 %) and oxidative conditions (30–70 %). In thermal compatibility the excipients PVP K-30, Compritol® 888 ATO, and MYRJ® 59 seem to exercise a protective thermal activity for the prototype. 相似文献
84.
85.
E.S. Medeiros S.L.T. de Souza R.O. Medrano-T I.L. Caldas 《Chaos, solitons, and fractals》2011,44(11):982-989
In the bi-dimensional parameter space of driven oscillators, shrimp-shaped periodic windows are immersed in chaotic regions. For two of these oscillators, namely, Duffing and Josephson junction, we show that a weak harmonic perturbation replicates these periodic windows giving rise to parameter regions correspondent to periodic orbits. The new windows are composed of parameters whose periodic orbits have the same periodicity and pattern of stable and unstable periodic orbits already existent for the unperturbed oscillator. Moreover, these unstable periodic orbits are embedded in chaotic attractors in phase space regions where the new stable orbits are identified. Thus, the observed periodic window replication is an effective oscillator control process, once chaotic orbits are replaced by regular ones. 相似文献
86.
Garcia CC Angeli JP Freitas FP Gomes OF de Oliveira TF Loureiro AP Di Mascio P Medeiros MH 《Journal of the American Chemical Society》2011,133(24):9140-9143
Acetaldehyde is an environmentally widespread genotoxic aldehyde present in tobacco smoke, vehicle exhaust and several food products. Endogenously, acetaldehyde is produced by the metabolic oxidation of ethanol by hepatic NAD-dependent alcohol dehydrogenase and during threonine catabolism. The formation of DNA adducts has been regarded as a critical factor in the mechanisms of acetaldehyde mutagenicity and carcinogenesis. Acetaldehyde reacts with 2'-deoxyguanosine in DNA to form primarily N(2)-ethylidene-2'-deoxyguanosine. The subsequent reaction of N(2)-ethylidenedGuo with another molecule of acetaldehyde gives rise to 1,N(2)-propano-2'-deoxyguanosine (1,N(2)-propanodGuo), an adduct also found as a product of the crotonaldehyde reaction with dGuo. However, adducts resulting from the reaction of more than one molecule of acetaldehyde in vivo are still controversial. In this study, the unequivocal formation of 1,N(2)-propanodGuo by acetaldehyde was assessed in human cells via treatment with [(13)C(2)]-acetaldehyde. Detection of labeled 1,N(2)-propanodGuo was performed by HPLC/MS/MS. Upon acetaldehyde exposure (703 μM), increased levels of both 1,N(2)-etheno-2'-deoxyguanosine (1,N(2)-εdGuo), which is produced from α,β-unsaturated aldehydes formed during the lipid peroxidation process, and 1,N(2)-propanodGuo were observed. The unequivocal formation of 1,N(2)-propanodGuo in cells exposed to this aldehyde can be used to elucidate the mechanisms associated with acetaldehyde exposure and cancer risk. 相似文献
87.
Cleidjane Gomes Faustino Fernando Antnio de Medeiros Allan Kardec Ribeiro Galardo Alex Bruno Lobato Rodrigues Rosany Lopes Martins Yuri de Medeiros Souza Lima Josean Fechine Tavares Marcos Antnio Alves de Medeiros Jader dos Santos Cruz Sheylla Susan Moreira da Silva de Almeida 《Molecules (Basel, Switzerland)》2020,25(22)
The aim of this work was to prepare a nanoemulsion containing the essential oil of Protium heptaphyllum resin and to evaluate the larvicidal activity and the residual larvicidal effect against Aedes aegypti. The essential oil was identified by gas chromatography coupled to a mass spectrometer, and the nanoemulsions were prepared using a low-energy method and characterized by photon correlation spectroscopy. The results indicated the major constituents as p-cimene (27.70%) and α-Pinene (22.31%). Nanoemulsions had kinetic stability and a monomodal distribution in a hydrophilic-lipophilic balance of 14 with particle diameters of 115.56 ± 1.68 nn and zeta potential of −29.63 ± 3.46 mV. The nanoemulsion showed larvicidal action with LC50 = 2.91 µg∙mL−1 and residual larvicidal effect for 72 h after application to A. aegypti larvae. Consequently, the nanobiotechnological product derived from the essential oil of P. heptaphyllum resin could be used against infectious disease vectors. 相似文献
88.
Valber Elias de Almeida Gean Bezerra da Costa David Douglas de Sousa Fernandes Paulo Henrique Gonçalves Dias Diniz Deysiane Brandão Ana Claudia Dantas de Medeiros Germano Véras 《Analytical and bioanalytical chemistry》2014,406(24):5989-5995
In this work, a new approach is proposed to verify the differentiating characteristics of five bacteria (Escherichia coli, Enterococcus faecalis, Streptococcus salivarius, Streptococcus oralis, and Staphylococcus aureus) by using digital images obtained with a simple webcam and variable selection by the Successive Projections Algorithm associated with Linear Discriminant Analysis (SPA-LDA). In this sense, color histograms in the red–green–blue (RGB), hue-saturation-value (HSV), and grayscale channels and their combinations were used as input data, and statistically evaluated by using different multivariate classifiers (Soft Independent Modeling by Class Analogy (SIMCA), Principal Component Analysis-Linear Discriminant Analysis (PCA-LDA), Partial Least Squares Discriminant Analysis (PLS-DA) and Successive Projections Algorithm-Linear Discriminant Analysis (SPA-LDA)). The bacteria strains were cultivated in a nutritive blood agar base layer for 24 h by following the Brazilian Pharmacopoeia, maintaining the status of cell growth and the nature of nutrient solutions under the same conditions. The best result in classification was obtained by using RGB and SPA-LDA, which reached 94 and 100 % of classification accuracy in the training and test sets, respectively. This result is extremely positive from the viewpoint of routine clinical analyses, because it avoids bacterial identification based on phenotypic identification of the causative organism using Gram staining, culture, and biochemical proofs. Therefore, the proposed method presents inherent advantages, promoting a simpler, faster, and low-cost alternative for bacterial identification. Figure
Summary of the new proposed methodology for bacteria classification by using color histograms and SPA-LDA 相似文献
89.
Maria Cristina Marcucci Carlos Rocha Oliveira Daniel Spindola Alyne A. Antunes Leila Y. K. Santana Victor Cavalaro Isabelle B. Costa Ana C. de Carvalho Thiago A. M. Veiga Livia S. Medeiros Lucas dos Santos Zamarioli Carolina P. Gonalves Milena F. Santos Simone S. Grecco Vanessa Y. Suzuki Lydia Masako Ferreira Daniel M. Garcia 《Molecules (Basel, Switzerland)》2022,27(17)
The aim of this study was to investigate the cytotoxic activity of the Coriandrum sativum (C. sativum) ethanolic extract (CSEE) in neuroblastoma cells, chemically characterize the compounds present in the CSEE, and predict the molecular interactions and properties of ADME. Thus, after obtaining the CSEE and performing its chemical characterization through dereplication methods using UPLC/DAD-ESI/HRMS/MS, PM6 methods and the SwissADME drug design platform were used in order to predict molecular interactions and ADME properties. The CSEE was tested for 24 h in neuroblastoma cells to the establishment of the IC50 dose. Then, the cell death was evaluated, using annexin-PI, as well as the activity of the effector caspase 3, and the protein and mRNA levels of Bax and Bcl-2 were analyzed by ELISA and RT-PCR, respectively. By UHPLC/DAD/HRMS-MS/MS analysis, the CSEE showed a high content of isocoumarins-dihydrocoriandrin, coriandrin, and coriandrones A and B, as well as nitrogenated compounds (adenine, adenosine, and tryptophan). Flavonoids (apigenin, hyperoside, and rutin), phospholipids (PAF C-16 and LysoPC (16:0)), and acylglicerol were also identified in lower amount as important compounds with antioxidant activity. The in silico approach results showed that the compounds 1 to 6, which are found mostly in the C. sativum extract, obey the “Five Rules” of Lipinski, suggesting a good pharmacokinetic activity of these compounds when administered orally. The IC50 dose of CSEE (20 µg/mL) inhibited cell proliferation and promoted cell death by the accumulation of cleaved caspase-3 and the externalization of phosphatidylserine. Furthermore, CSEE decreased Bcl-2 and increased Bax, both protein and mRNA levels, suggesting an apoptotic mechanism. CSEE presents cytotoxic effects, promoting cell death. In addition to the promising results predicted through the in silico approach for all compounds, the compound 6 showed the best results in relation to stability due to its GAP value. 相似文献
90.
M Pattabiraman G Rangarajan Kwang-Yong Choi P Lemmens G Guentherodt G Balakrishnan DMcK Paul MR Lees 《Pramana》2002,58(5-6):1013-1017
We report polarized Raman scattering in single crystals of Nd0.7Sr0.3MnO3. The temperature dependence of the MnO6 octahedral bending and stretching modes observed in the XX spectra points to the existence of local lattice distortions,
possibly polarons. The XY spectra have been analyzed using a collision-dominated model, which allows the extraction of the
carrier scattering rate. 相似文献