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701.
María J. Tapia María Monteserín Hugh D. Burrows João S. Seixas de Melo Joan Estelrich 《Photochemistry and photobiology》2013,89(6):1471-1478
We have studied the effect of head group and alkyl chain length on β‐phase formation in poly(9,9‐dioctylfluorene) (PFO) solubilized in phospholipid liposomes. Systems studied have three different alkyl chain lengths (1,2‐dimyristoyl‐sn‐glycero‐3‐phosphatidylcholine [DMPC], 1,2‐didodecanoyl‐sn‐glycero‐3‐phosphatidylcholine [DLPC], 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphatidylcholine [DPPC]) and head groups (1,2‐dimyristoyl‐sn‐glycero‐3‐phosphate monosodium salt [DMPA], 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphoethanolamine [DMPE] and 1,2‐dimyristoyl‐sn‐glycero‐3‐phospho‐l ‐serine sodium salt [DMPS]). Changes in liposome size upon addition of PFO are followed by dynamic light scattering. All the phospholipids induce the formation of PFO β‐phase, which is followed by the emission intensity and deconvolution of the absorption spectra. Both the head group and alkyl chain length affect the yield of β‐phase. The photophysics of PFO incorporated in liposomes is characterized by stationary and time‐resolved fluorescence, whereas the polymer‐phospholipid interactions have been studied by the effect of the PFO concentration on the phospholipid phase transitions (differential scanning calorimetry [DSC]). 相似文献
702.
703.
Stella Gomes Rodrigues Izabel de Souza Chaves Nathalie Ferreira Silva de Melo Marcelo Bispo de Jesus Leonardo Fernandes Fraceto S��rgio Ant?nio Fernandes Eneida de Paula Matheus Puggina de Freitas Luciana de Matos Alves Pinto 《Journal of inclusion phenomena and macrocyclic chemistry》2011,70(1-2):19-28
Schistosomiasis is still an endemic disease in many regions, with 250 million people infected with Schistosoma and about 500,000 deaths per year. Praziquantel (PZQ) is the drug of choice for schistosomiasis treatment, however it is classified as Class II in the Biopharmaceutics Classification System, as its low solubility hinders its performance in biological systems. The use of cyclodextrins is a useful tool to increase the solubility and bioavailability of drugs. The aim of this work was to prepare an inclusion compound of PZQ and methyl-??-cyclodextrin (MeCD), perform its physico-chemical characterization, and explore its in vitro cytotoxicity. SEM showed a change of the morphological characteristics of PZQ:MeCD crystals, and IR data supported this finding, with changes after interaction with MeCD including effects on the C?CH of the aromatic ring, observed at 758 cm?1. Differential scanning calorimetry measurements revealed that complexation occurred in a 1:1 molar ratio, as evidenced by the lack of a PZQ transition temperature after inclusion into the MeCD cavity. In solution, the PZQ UV spectrum profile in the presence of MeCD was comparable to the PZQ spectrum in a hydrophobic solvent. Phase solubility diagrams showed that there was a 5.5-fold increase in PZQ solubility, and were indicative of a type AL isotherm, that was used to determine an association constant (Ka) of 140.8 M?1. No cytotoxicity of the PZQ:MeCD inclusion compound was observed in tests using 3T3 cells. The results suggest that the association of PZQ with MeCD could be a good alternative for the treatment of schistosomiasis. 相似文献
704.
Optimization of the extraction conditions of the volatile compounds from chili peppers by headspace solid phase micro-extraction 总被引:2,自引:0,他引:2
Junior SB de Marchi Tavares de Melo A Zini CA Godoy HT 《Journal of chromatography. A》2011,1218(21):3345-3350
A method involving headspace-solid phase micro-extraction (HS-SPME), gas chromatography with flame ionization detection (GC-FID) and gas chromatography with mass spectrometry (GC-MS) was developed and optimized to investigate the volatile composition of Capsicum chili peppers. Five SPME fibers were tested for extraction: carboxen/polydimethylsiloxane (CAR/PDMS-75μm), polydimethylsiloxane (PDMS-100μm), divinylbenzene/polydimethylsiloxane (DVB/PDMS-65μm), carbowax/divinylbenzene (CW/DVB-70μm), and divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS-50/30μm), the last of which was shown to be the most efficient fiber to trap the volatile compounds. Optimization of the extraction conditions was carried out using multivariate strategies such as factorial design and response surface methodology. Eighty three compounds were identified by GC-MS when using the optimized extraction conditions, the majority of which were esters. 相似文献
705.
Drio Rodrigues do Nascimento Junior Antonio Tabernero Elaine Christine de Magalhes Cabral Albuquerque Silvio Alexandre Beisl Vieira de Melo 《Molecules (Basel, Switzerland)》2021,26(13)
As an alternative to synthetic pesticides, natural chemistries from living organisms, are not harmful to nontarget organisms and the environment, can be used as biopesticides, nontarget. However, to reduce the reactivity of active ingredients, avoid undesired reactions, protect from physical stress, and control or lower the release rate, encapsulation processes can be applied to biopesticides. In this review, the advantages and disadvantages of the most common encapsulation processes for biopesticides are discussed. The use of supercritical fluid technology (SFT), mainly carbon dioxide (CO2), to encapsulate biopesticides is highlighted, as they reduce the use of organic solvents, have simpler separation processes, and achieve high-purity particles. This review also presents challenges to be surpassed and the lack of application of SFT for biopesticides in the published literature is discussed to evaluate its potential and prospects. 相似文献
706.
M. A. S. Melo D. M. de-Paula J. P. M. Lima F. M. C. Borges C. Steiner-Oliveira M. Nobre-dos-Santos I. C. J. Zanin E. B. Barros L. K. A. Rodrigues 《Laser Physics》2010,20(6):1504-1513
The development of a method to ensure bacterial-free substrates without extensive cavity preparation would be highly useful
to dentistry, since there is no currently available effective method for killing residual bacteria in dentinal tissue. This
randomized in vitro study determined parameters for using toluidine blue O (TBO) with a light-emitting diode (LED) for dentine
caries disinfection and monitored intrapulpal/periodontal temperatures during irradiation. Occlusal human dentine slabs were
immersed in Streptococcus mutans culture for demineralization induction. Slabs were allocated to 10 groups (n = 15), which were treated with 0.1 mg ml−1 TBO with 5 min of incubation time or 0.9% NaCl solution for 5, 10 or 15 min, and submitted or not to irradiation for 5, 10
or 15 min (47, 94, and 144 J/cm2). Before and after treatments, dentine samples were analyzed with regard to S. mutans counts. In whole teeth, temperature in pulp and periodontium was measured by thermocouples during irradiation. Kruskal-Wallis/Student-Newman-Keuls,
and ANOVA/Tukey test were respectively utilized to compare log reductions and temperature rises between groups. Bacterial
reduction was observed when dentine was exposed to both TBO and LED at all irradiation times, as well as to LED alone for
10 and 15 min. Temperature increases lower than 2°C were observed for either pulp or periodontium. Concluding, LED combined
with TBO is a safe and effective approach for dentine caries disinfection. Nevertheless, additional studies should be conducted
to determine the influence of the irradiation in S. mutans viability in dentinal surface/tubules. 相似文献
707.
J. A. Lima P. T. C. Freire F. E. A. Melo J. Mendes Filho G. P. De Sousa R. J. C. Lima P. F. Faanha Filho H. N. Bordallo 《Journal of Raman spectroscopy : JRS》2010,41(7):808-813
Raman spectra of DL ‐Alanine crystals were investigated in the 50–3200 cm−1 spectral region for temperatures ranging from 15 to 295 K. The crystalline structure of DL ‐Alanine represents a rare example of an amino acid racemate crystallizing in a non‐centrosymmetric space group. From this study, we have observed changes in the wavenumber of modes associated with both rocking of CO2− and skeletal vibrations. On the other hand, neither changes in the modes associated to CH or CH3 vibrations nor substantial modifications of the lattice modes of the crystal were observed. Such result indicates slight changes of the CO2 group orientation without observation of a solid–solid phase transition in the DL ‐Alanine crystal. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
708.
Pedro Silvino Pereira Carlos Vinicius Barros Oliveira Ana Josicleide Maia Maria Celeste Vega-Gomez Miriam Roln Cathia Coronel Antnia Eliene Duarte Henrique Douglas Melo Coutinho Abolghasem Siyadatpanah Roghayeh Norouzi Seyed Jafar Adnani Sadati Polrat Wilairatana Teresinha Gonalves Silva 《Molecules (Basel, Switzerland)》2022,27(9)
Cymbopogon winterianus, known as “citronella grass”, is an important aromatic and medicinal tropical herbaceous plant. The essential oil of C. winterianus (EOCw) is popularly used to play an important role in improving human health due to its potential as a bioactive component. The present study aimed to identify the components of the essential oil of C. winterianus and verify its leishmanicidal and trypanocidal potential, as well as the cytotoxicity in mammalian cells, in vitro. The EOCw had geraniol (42.13%), citronellal (17.31%), and citronellol (16.91%) as major constituents. The essential oil only exhibited significant cytotoxicity in mammalian fibroblasts at concentrations greater than 250 μg/mL, while regarding antipromastigote and antiepimastigote activities, they presented values considered clinically relevant, since both had LC50 < 62.5 μg/mL. It can be concluded that this is a pioneer study on the potential of the essential oil of C. winterianus and its use against the parasites T. cruzi and L. brasiliensis, and its importance is also based on this fact. Additionally, according to the results, C. winterianus was effective in presenting values of clinical relevance and low toxicity and, therefore, an indicator of popular use. 相似文献
709.
Henrique S. Fernandes Nuno M. F. S. A. Cerqueira Srgio F. Sousa Andr Melo 《Molecules (Basel, Switzerland)》2022,27(17)
The partitioning of the molecular mechanics (MM) energy in calculations involving biomolecular systems is important to identify the source of major stabilizing interactions, e.g., in ligand–protein interactions, or to identify residues with considerable contributions in hybrid multiscale calculations, i.e., quantum mechanics/molecular mechanics (QM/MM). Here, we describe Energy Split, a software program to calculate MM energy partitioning considering the AMBER Hamiltonian and parameters. Energy Split includes a graphical interface plugin for VMD to facilitate the selection of atoms and molecules belonging to each part of the system. Energy Split is freely available at or can be easily installed through the VMD Store. 相似文献
710.
Michele Trombin de Souza Mireli Trombin de Souza Maíra Chagas Morais Daiana da Costa Oliveira Douglas Jos de Melo Leonardo Figueiredo Paulo Henrique Gorgatti Zarbin Maria Aparecida Cassilha Zawadneak Daniel Bernardi 《Molecules (Basel, Switzerland)》2022,27(19)
The spotted wing drosophila (Drosophila suzukii) is one of the main invasive pests of small fruits in the world. Thus, 19 essential oils (EOs) were selected to analyze the effects through toxicity and repellency on oviposition and D. suzukii adults. In addition, their lethal and sublethal effects on the pupal endoparasitoid Trichopria anastrephae were evaluated. The EOs of C. flexuosus and Mentha spp. had the highest toxicity observed in the topical application bioassay for D. suzukii. In contrast, the EOs of C. verum, C. citratus QT citratus, and C. winterianus showed the highest toxicity in the ingestion bioassay for D. suzukii. The dry residues of C. verum and C. citratus QT citratus reduced the oviposition of D. suzukii. In the repellency bioassays, the 19 EOs analyzed repelled ≅ 90% of the D. suzukii females. All EOs evaluated using the LC90 values of the products provided mortality of less than 20% of T. anastrephae adults and did not cause a reduction in the parasitism of surviving T. anastrephae females. We conclude that the EOs evaluated have the potential to be used in the management of D. suzukii. They can also serve as selective active ingredients for the formulation and synthesis of new biopesticides. 相似文献