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41.
Willian Kopp Hernane S. Barud Marcelo F. Paz Luciano A. Bueno Raquel L. C. Giordano Sidney J. L. Ribeiro 《Journal of Sol-Gel Science and Technology》2012,63(2):219-223
The addition of calcium chloride eletrolyte to sodium polyphosphate solutions lead to Calcium polyphosphate coacervates. The effects of a thermal treatment were investigated with the objective to increase the relative stability of the obtained material. Thermogravimetry analysis indicates that coacervates became less hydrophilic and more thermally stable after the thermal treatment. Crystallization was identified through differential scanning calorimetry and X-ray diffraction. Morphological changes were observed after the thermal treatment by scanning electron microscopy. N2 adsorption?Cdesorption isotherms suggest that both materials, thermally treated or not, display type IV isotherms, low superficial area and mesoporous structure. Stability experiments in solutions at different pH values show that the thermally treated calcium polyphosphate is relatively more stable than the non-treated coacervate. 相似文献
42.
Adriana Predoi−Cross Michel Herman Luciano Fusina Gianfranco Di Lonardo 《Journal of Quantitative Spectroscopy & Radiative Transfer》2012,113(11):1134-1137
The far infrared spectrum of HCOOH was recorded at a high resolution (0.0009 cm?1) and long path length (72 m) at the far-infrared beamline, Canadian Light Source. Spectra were recorded in the region 62–300 cm?1, showing transitions from the trans-isomer.Ground state rotational transitions with Ka up to 30, were identified up to 175 cm?1, extending the observation reported in the literature. A total of 3321 transitions were assigned and fitted together with previous (4149) published data. An improved set of rotational parameters was obtained adopting the symmetric top (A) reduction of the rotational Hamiltonian in the Ir representation. The newly measured far infrared transitions allowed the determination of all diagonal and off diagonal 8th order parameters L and of some of the diagonal 10th order parameters P. 相似文献
43.
Renata Longhini Traudi Klein Marcos Luciano Bruschi Waldir Veríssimo da Silva Jr Juliana Rodrigues Norberto Peporine Lopes João Carlos Palazzo de Mello 《Journal of separation science》2013,36(7):1247-1254
The phenolic compounds are the main phytochemical constituents of the bark of Trichilia catigua and are commonly used for medicinal purposes. An HPLC method for the simultaneous quantification of phenolic compounds (procyanidin B2 (PB2), epicatechin (EPC), chinchonains Ia, Ib, IIa, IIb, catechin, and chrologenic acid) in T. catigua extract was developed and validated. A suitable chromatographic system was selected, which uses a gradient elution with methanol/ACN (75:25), and water both with 0.05% TFA, as mobile phase, column Luna, 280 nm, and flow 0.4 mL/min. Validation of the analytical method was based on the parameters: linearity, precision, LODs and LOQs, accuracy, robustness, and stability. The method showed linearity for PB2 and EPC, in the range 10–120 μg/mL with good correlation coefficients (>0.996). For precision, the repeatability ranged from 1.89 to 3.23%, and the values for accuracy for PB2 and EPC were 95 and 89%, respectively. The LODs and LOQs for PB2 were 1.36 and 4.12 μg/mL, and for EPC were 2.18 and 6.61 μg/mL, respectively. The method was robust under the conditions employed. The proposed method could be employed for quality assessment of T. catigua, as well as pharmaceutical products. 相似文献
44.
Anderson R. L. Caires Luciano R. Costa Joelson Fernandes 《Central European Journal of Chemistry》2013,11(1):111-115
In the last few years, silver nanoparticles have been proposed as a promising alternative for the label-free detection of proteins via metal-enhanced fluorescence. Generally, the aromatic amino acid tryptophan is most frequently used in this type of studies, because the intrinsic fluorescence of proteins is usually dominated by tryptophan emissions. In the present study, we evaluated the fluorescence behavior of tryptophan in the presence of a silver colloid with nanoparticles of 100 nm in diameter. The results showed that a nanoparticles concentration of 32 mg L?1 induced maximum fluorescence enhancement. However, the metal-enhanced fluorescence was dependent on the emission wavelength of tryptophan, and this phenomenon was closely related to the metal surface reabsorption process (inner filter effect), suggesting that the plasmon resonance reabsorption effect should be taken into account in analyses involving protein studies by metal-enhanced fluorescence. 相似文献
45.
Fei Li Paolo Biagioni Monica Bollani Andrea Maccagnan Luciano Piergiovanni 《Cellulose (London, England)》2013,20(5):2491-2504
In this paper, we systematically address the performance of cellulose nanocrystals (CNs) coated flexible food packaging films. Firstly, the morphology of CNs from cotton linters and homogeneity of its coating on different substrates were characterized by transmission electronic microscopy and atomic force microscopy. Then, the 1.5 μm thick CNs coating on polyethylene terephthalate (PET), oriented polypropylene, oriented polyamide (OPA), and cellophane films were characterized for their mechanical, optical, anti-fog, and barrier properties. CNs coating reduces the coefficient of friction while maintaining high transparency (~90 %) and low haze (3–4 %) values, and shows excellent anti-fog properties and remarkable oxygen barrier (oxygen permeability coefficient of CNs coating, P’O2, 0.003 cm3 μm m?2 24 h?1 kPa?1). In addition, the Gelbo flex test combined with oxygen permeance (PO2) measurements and optical microscopy are firstly reported for evaluating the durability of coatings, revealing that the CNs coated PET and OPA provide the best performance among the investigated coated films. CNs are therefore considered to be a promising multi-functional coating for flexible food packaging. 相似文献
46.
47.
Giovanni B. Giovenzana Claudia Guanci Silvia Demattio Luciano Lattuada Veronica Vincenzi 《Tetrahedron》2014
Bifunctional chelating agents (BFCAs) are small molecules containing a chelating unit, able to strongly coordinate a metal ion, and a reactive functional group, devised to form a stable covalent bond with another molecule. BFCAs are widely employed since their conjugation to a suitable biomolecule (e.g., a peptide or an antibody) allows the synthesis of diagnostic or therapeutic agents that specifically target diseased tissue with metals or radiometals. For this reason, BFCAs find application in diagnostic imaging, molecular imaging, and radiotherapy of cancer. The synthesis of new BFCAs based on a diethylenetriaminepentaacetic acid (DTPA) structure in which one or two carboxylic groups are replaced with phosphonic units is described. The phosphonic group, aside from being a classical isostere of the carboxylic acid in coordination chemistry, allows to modulate the physico-chemical properties of the ligands and of the corresponding complexes. 相似文献
48.
Machado Poliana A. L. Cavalcanti Marcello H. S. Silva Fábio A. B. de Almeida Eduardo T. Cardoso Marcus V. C. Mesquita Anderson F. Lemes Nelson H. T. Virtuoso Luciano S. 《Journal of solution chemistry》2022,51(3):320-344
Journal of Solution Chemistry - Liquid–liquid equilibrium (LLE) data and phase diagrams for new aqueous two-phase systems (ATPSs) containing 1-butyl-3-methylimidazolium chloride... 相似文献
49.
Jeferson Rodrigo Souza Pina Joo Victor Silva-Silva Josiwander Miranda Carvalho Heriberto Rodrigues Bitencourt Luciano Almeida Watanabe Juan Matheus Pereira Fernandes Guilherme Eduardo de Souza Anna Caroline Campos Aguiar Rafael Victorio Carvalho Guido Fernando Almeida-Souza Ktia da Silva Calabrese Patrícia Santana Barbosa Marinho Andrey Moacir do Rosario Marinho 《Molecules (Basel, Switzerland)》2021,26(11)
The natural compound ravenelin was isolated from the biomass extracts of Exserohilum rostratum fungus, and its antimicrobial, antiplasmodial, and trypanocidal activities were evaluated. Ravenelin was isolated by column chromatography and HPLC and identified by NMR and MS. The susceptibility of Gram-positive and Gram-negative bacteria strains to ravenelin was determined by microbroth dilution assay. Cytotoxicity was evaluated in hepatocarcinoma cells (HepG2) and BALB/c peritoneal macrophages by using MTT. SYBR Green I-based assay was used in the asexual stages of Plasmodium falciparum. Trypanocidal activity was tested against the epimastigote and intracellular amastigote forms of Trypanosoma cruzi. Ravenelin was active against Gram-positive bacteria strains, with emphasis on Bacillus subtilis (MIC value of 7.5 µM). Ravenelin’s antiparasitic activities were assessed against both the epimastigote (IC50 value of 5 ± 1 µM) and the intracellular amastigote forms of T. cruzi (IC50 value of 9 ± 2 µM), as well as against P. falciparum (IC50 value of 3.4 ± 0.4 µM). Ravenelin showed low cytotoxic effects on both HepG2 (CC50 > 50 µM) and peritoneal macrophage (CC50 = 185 ± 1 µM) cells with attractive selectivity for the parasites (SI values > 15). These findings indicate that ravenelin is a natural compound with both antibacterial and antiparasitic activities, and considerable selectivity indexes. Therefore, ravenelin is an attractive candidate for hit-to-lead development. 相似文献
50.
Valentina Marturano Francesco Abate Veronica Ambrogi Valeria Califano Pierfrancesco Cerruti Giovanni Piero Pepe Luciano R. M. Vicari Giovanni Ausanio 《Molecules (Basel, Switzerland)》2021,26(9)
Herein, smart coatings based on photo-responsive polymer nanocapsules (NC) and deposited by laser evaporation are presented. These systems combine remotely controllable release and high encapsulation efficiency of nanoparticles with the easy handling and safety of macroscopic substrates. In particular, azobenzene-based NC loaded with active molecules (thyme oil and coumarin 6) were deposited through Matrix-Assisted Pulsed Laser Evaporation (MAPLE) on flat inorganic (KBr) and organic (polyethylene, PE) and 3D (acrylate-based micro-needle array) substrates. SEM analyses highlighted the versatility and performance of MAPLE in the fabrication of the designed smart coatings. DLS analyses, performed on both MAPLE- and drop casting-deposited NC, demonstrated the remarkable adhesion achieved with MAPLE. Finally, thyme oil and coumarin 6 release experiments further demonstrated that MAPLE is a promising technique for the realization of photo-responsive coatings on various substrates. 相似文献