2,632 research outputs found
The Crystal-t Algorithm: A New Approach To Calculate The Sle Of Lipidic Mixtures Presenting Solid Solutions.
Lipidic mixtures present a particular phase change profile highly affected by their unique crystalline structure. However, classical solid-liquid equilibrium (SLE) thermodynamic modeling approaches, which assume the solid phase to be a pure component, sometimes fail in the correct description of the phase behavior. In addition, their inability increases with the complexity of the system. To overcome some of these problems, this study describes a new procedure to depict the SLE of fatty binary mixtures presenting solid solutions, namely the Crystal-T algorithm. Considering the non-ideality of both liquid and solid phases, this algorithm is aimed at the determination of the temperature in which the first and last crystal of the mixture melts. The evaluation is focused on experimental data measured and reported in this work for systems composed of triacylglycerols and fatty alcohols. The liquidus and solidus lines of the SLE phase diagrams were described by using excess Gibbs energy based equations, and the group contribution UNIFAC model for the calculation of the activity coefficients of both liquid and solid phases. Very low deviations of theoretical and experimental data evidenced the strength of the algorithm, contributing to the enlargement of the scope of the SLE modeling.1616740-5
Kraft lignin solubility and its chemical modification in deep eutectic solvents
Lignin stands as a promising raw material to produce commodities and specialty chemicals, yet its poor solubility remains a big challenge. Recently, deep eutectic solvents (DES) have been proposed as sustainable solvents with high potential to dissolve and valorize lignin. In the present study, the ability of DES based on cholinium chloride ([Ch]Cl) combined with alcohols and carboxylic acids as hydrogen bond donors (HBDs) to dissolve kraft lignin and to change its chemical structure was examined. The influence of the chemical nature of HBDs, water content, and HBD:hydrogen bond acceptor (HBA) molar ratio on the solubility of kraft lignin in DES was studied (313.15 K). The kraft lignin solubility was enhanced by increasing both the HBD’s carbon chain length and the molar ratio, with [Ch]Cl:HEXA (1,6-hexanediol) and [Ch]Cl:MaleA (maleic acid) being the best studied solvents for kraft lignin dissolution, while the addition of water was a negative factor. The thermal treatments (393.15 K) of kraft lignin show that carboxylic acid-based DES promote chemical modifications to kraft lignin, including the disruption of several C–O covalent type bonds (e.g., β-O-4, α-O-4 and α-O-α), while alcohol-based DES were found to be nonderivatizing solvents maintaining the lignin chemical structure. These results show the versatility of DES, which, depending on their chemical nature, may offer distinct strategies for lignin valorization.publishe
Fast and efficient method to evaluate the potential of eutectic solvents to dissolve lignocellulosic components
The application of eutectic solvents (ESs) in lignocellulosic biomass fractionation has been demonstrated as a promising approach to accomplish efficient and environmentally friendly biomass valorization. In general, ESs are a combination of two components, a hydrogen-bonding donor and a hydrogen-bonding acceptor, in which the melting point of the mixture is lower than that of the individual components. However, there are plenty of possible combinations to form ESs with the potential to apply in biomass processing. Therefore, the development of fast and effective screening methods to find combinations capable to dissolve the main biomass components—namely cellulose, hemicelluloses, and lignin—is highly required. An accurate and simple technique based on optical microscopy with or without polarized lenses was used in this study to quickly screen and monitor the dissolution of cellulose, xylose (a monomer of hemicelluloses), and lignin in several ESs. The dissolution of these solutes were investigated in different choline-chloride-based ESs (ChCl:UREA, ChCl:PROP, ChCl:EtGLY, ChCl:OXA, ChCl:GLY, ChCl:LAC). Small amounts of solute and solvent with temperature control were applied and the dissolution process was monitored in real time. The results obtained in this study showed that cellulose was insoluble in these ESs, while lignin and xylose were progressively dissolved.publishe
IL-1R and inflammasomes mediate early pulmonary protective mechanisms in respiratory brucella abortus infection
Brucella spp. infection is frequently acquired through contaminated aerosols. The role of interleukin-1 beta (IL-1β) in the early pulmonary response to respiratory Brucella infection is unknown. As shown here, IL-1β levels in lung homogenates and bronchoalveolar lavage fluid (BALF) of mice intratracheally inoculated with B. abortus were increased at 3 and 7 days p.i. At 7 days p.i., pulmonary CFU numbers were higher in IL-1 receptor (IL-1R) knockout (KO) mice than in wild type (WT) mice. At different times p.i. CFU in lungs and BALF were higher in mice lacking some inflammasome components (caspase-1, AIM2, NLRP3) than in WT mice. At 2 days p.i. pulmonary levels of IL-1b and CXCL1 (neutrophils chemoattractant) were lower in caspase-1/11 KO mice. At day 3 p.i., neutrophils counts in BALF were lower in caspase-1/11 KO mice than in WT mice. During in vitro infections, IL-1β secretion was lower in alveolar macrophages from caspase-1/11, NLRP3 or AIM2 KO mice than in WT controls. Similarly, IL-1β production by B. abortus-infected alveolar epithelial cells was reduced by pretreatment with a specific caspase-1 inhibitor. This study shows that IL-1R, probably through IL-1β action, and the NLRP3 and AIM2 inflammasomes are involved in pulmonary innate immune protective mechanisms against respiratory B. abortus infection.Fil: Hielpos, MarÃa Soledad. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica; ArgentinaFil: Fernandez, Andrea Giselle. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Falivene, Juliana. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Alonso Paiva, Iván Mathias. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Muñoz González, Florencia. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Ferrero, Mariana Cristina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Campos, Priscila C.. Universidade Federal de Minas Gerais; BrasilFil: Vieira, Angelica T.. Universidade Federal de Minas Gerais; BrasilFil: Oliveira, Sergio Costa. Universidade Federal de Minas Gerais; BrasilFil: Baldi, Pablo Cesar. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; Argentin
Octanol–water partition coefficients and aqueous solubility data of monoterpenoids: experimental, modeling, and environmental distribution
Terpenes and terpenoids encompass one of the most extensive
and valuable classes of secondary metabolites. Their ten-carbon-containing
oxygenated representatives, monoterpenoids, are the main components of plant
essential oils, being widely exploited in the cosmetic, pharmaceutical, and food
industrial areas. Due to its widespread use, it is crucial to investigate their
environmental distribution. Thus, new water solubility data were obtained for
six monoterpenoids ((1R)-(+)-camphor, (S)-(+)-carvone, eucalyptol, (1R)-
(−)-fenchone, L-(−)-menthol, and (−)-menthone) at 298.2 and 313.2 K.
Furthermore, octanol−water partition coefficients of 12 monoterpenoids (the
six mentioned above plus carvacrol, (±)-β-citronellol, eugenol, geraniol, linalool,
and thymol) were measured at 298.2 K. The COSMO-RS thermodynamic
model and other more empirical approaches were evaluated for the description
of the solubilities and partition coefficients, showing reliable predictions. Lastly, the distribution of the monoterpenoids in the
different environmental compartments was assessed through an intuitive two-dimensional chemical space diagram based on the
physicochemical equilibrium information reported.This work was developed within the scope of the project
CIMO-Mountain Research Center, UIDB/00690/2020, and
CICECO-Aveiro Institute of Materials, UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through
the Portuguese Foundation for Science and Technology
(FCT)/MCTES. S.M.V.-B. thanks FCT and the European
Social Fund (ESF) for his Ph.D. grant (SFRH/BD/138149/2018). M.C.d.C. would also like to thank CNPq (306666/
2020-0) and FAPESP (2014/21252-0).info:eu-repo/semantics/publishedVersio
Estimating the Coronal Supra-Arcade Downflow Radio Emission: From Centimeter Through Submillimeter Wavelengths
Supra-arcade downflows (SADs) are infrequent, wiggly, and low-emission structures observed to descend through the solar corona, mostly in EUV and soft X-ray frequencies. Based on their physical characteristics, SADs have been interpreted as low-density bubbles and are related to magnetic reconnection processes during long-term erupting flares. In this work, we use numerical MHD simulations to compute flux density maps, which are convolved with telescope beams to synthesize images with the aim to assess the expected SAD emission in radio wavelengths. We assume that the emission is thermal bremsstrahlung from a fully ionized plasma and without any appreciable gyroresonance contribution since magnetic fields are of the order of 10 G. We find that SAD emission should be optically thin in the frequency range of [10–1,000] GHz, and the spatially integrated flux should be larger than 1 Jy. We conclude, therefore, that SADs consistently are less bright than the surrounding fan and that observing SADs in radio frequencies between [0.5–1,000] GHz is feasible with present instrumentation. The observing strategies are proposed, including the instruments that can be used. Moreover, since the emission is, for the most part, optically thin, the flux density is proportional to temperature, density, and line-of-sight depth and when combined with EUV and soft X-ray images may allow a better density and temperature determination of SADs.Fil: Zurbriggen, Ernesto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de AstronomÃa y FÃsica del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de AstronomÃa y FÃsica del Espacio; Argentina. Universidade Presbiteriana Mackenzie; BrasilFil: Giménez de Castro, C. Guillermo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de AstronomÃa y FÃsica del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de AstronomÃa y FÃsica del Espacio; ArgentinaFil: Costa, Andrea. Universidade Presbiteriana Mackenzie; Brasil. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Córdoba. Instituto de AstronomÃa Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de AstronomÃa Teórica y Experimental; ArgentinaFil: Cécere, Mariana Andrea. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Córdoba. Instituto de AstronomÃa Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de AstronomÃa Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Selhorst, Caius L.. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
BODIPY derivatives: synthesis and evaluation of their optical properties
3-Difluoroborodipyrromethene, commonly known as BODIPY has been used in many innovative applications such as biological fluorescent labelling, electroluminescent devices, tunable laser dyes, components for solid state solar cells, photodynamic therapy and optical sensors (fluorimetric or colorimetric). The numerous desirable properties of BODIPY explain its growing success over recent years. It is endowed with chemical, structural and photochemical stability, both in solution and in solid state. Furthermore, it possesses a high coefficient of molar absorptivity, high quantum yield of fluorescence, negligible triplet formation and narrow band emission with high intensity peaks. Furthermore, its photophysical properties can be tuned/improved introducing groups at suitable positions in the BODIPY core.
In continuation of the work developed in our research group, we report in this communication the synthesis, characterization and evaluation of the optical properties of BODIPY derivatives having in mind their potential application as novel chromofluorogenic sensors and/or fluorescent probes for the detection of molecules, cations and anions with biological and medicinal relevance.Thank are due to Fundação para a Ciência e Tecnologia (Portugal) and FEDERCOMPETE
for financial support through Centro de QuÃmica (UID/ QUI/0686/2016). The NMR
spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within
the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005
with funds from POCI 2010 (FEDER) and FCT.info:eu-repo/semantics/publishedVersio
Contribution of plant-derived phenolic compounds to combat Candida species biofilms
Opportunistic fungal infections, namely involving Candida species,
constitute a hot topic for scientific researchers. The present work aims to
access antifungal potential of plant-derived phenolic extracts against
planktonic cells and biofilms of Candida species. Eucalyptus globulus
Labill. (blue gum), Glycyrrhiza glabra L. (licorice), Juglans regia L.
(walnut) and Salvia officinalis L. (sage) evidenced to be the most effective
Candida growth inhibitors, using disc diffusion assay. Minimal inhibitory
(MIC) and minimal fungicidal (MFC) concentrations, and chemical
composition of extracts by using HPLC-DAD-ESI/MS were also
determined. Blue gum and walnut mainly exerted fungistatic potential,
while sage exerted an interesting anti-Candida potential. However, the
most prominent candidacidal potential was observed to licorice extract,
being achieved the lowest MIC and MFC values. The candidacidal
potential of these phenolic extracts was mainly attributed to their high
abundance in flavonoids, mainly flavones: luteolin (sage) and apigenin
derivatives (licorice), and flavanones: liquiritin derivatives (licorice). In
order to deepen the knowledge on the most effective extract, its ability to
inhibit biofilm formation was evaluated. Overall, a double concentration of
MFC value was necessary to achieve similar results in biofilms. Flow
cytometry assays were also carried out, and the obtained results revealed
that primary lesion of cellular membrane appear to be most relevant
mode of action. Thus, plant derived phenolic compounds evidence a
promising potential to combat Candida species biofilms, both individually
or combined with conventional therapy
- …