Chemical Characterization of Flowers and Leaf Extracts Obtained from Turnera subulata and Their Immunomodulatory Effect on LPS-Activated RAW 264.7 Macrophages

The anti-inflammatory properties of Turnera subulata have been evaluated as an alternative drug approach to treating several inflammatory processes. Accordingly, in this study, aqueous and hydroalcoholic extracts of T. subulata flowers and leaves were analyzed regarding their phytocomposition by ultrafast liquid chromatography coupled to mass spectrometry, and their anti-inflammatory properties were assessed by an in vitro inflammation model, using LPS-stimulated RAW-264.7 macrophages. The phytochemical profile indicated vitexin-2-O-rhamnoside as an important constituent in both extracts, while methoxyisoflavones, some bulky amino acids (e.g., tryptophan, tyrosine, phenylalanine), pheophorbides, and octadecatrienoic, stearidonic, and ferulic acids were detected in hydroalcoholic extracts. The extracts displayed the ability to modulate the in vitro inflammatory response by altering the secretion of proinflammatory (TNF-α, IL-1β, and IL-6) and anti-inflammatory (IL-10) cytokines and inhibiting the PGE-2 and NO production. Overall, for the first time, putative compounds from T. subulata flowers and leaves were characterized, which can modulate the inflammatory process. Therefore, the data highlight this plant as an option to obtain extracts for phytotherapic formulations to treat and/or prevent chronic diseases.     

Factors affecting the competitive reduction of 8,8-dimethylnaphthalene-1,4,5(8H)-trione in a Diels–Alder cycloaddition with hydroxysulfinyldienes

Competing reduction and cycloaddition products were formed in the reaction of 8,8-dimethylnaphthalene-1,4,5(8H)-trione with a hydroxysulfinyldiene. The ratio of reduction to cycloaddition products depended on the stereochemistry of the diene and on the solvent employed, being higher in ethanol than in benzene. The ratio was also affected by the addition of Lewis acids, decreasing in the order BF₃ = Al₂O₃ > MgCl₂ > ZnCl₂. The results help to explain and predict the occurrence of these competing processes in Diels–Alder cycloadditions involving quinonedienophiles.     

Gamma to alpha phase transformation in FeCoV alloys

The effects of filing FeCoV alloys with equiatomic FeCo and up to 14 at% V is studied by Mössbauer spectroscopy and X-ray diffraction. We observed that filing eliminates the paramagnetic component observed in samples in the form of plates. The filed material also presents a linear increase of the lattice parameter and a linear decrease of the average hyperfine field of the alpha phase due to extra low-field satellites with increasing vanadium contents. This indicates that filing produces a gamma to alpha phase transformation, which increases the amount of vanadium in solid solution in the FeCo alpha phase.     

Phase-field simulation of a Fe-Mn alloy under forced flow conditions

In this work a study through numerical simulation of dendritic growth for the system Fe-Mn under the influence of a forced flow field is presented. The investigations are based on an extension of the quantitative phase-field approach developed by Echebarria et. al. Phy. Rev. E 061604 (2004), to simulate the solidification of Fe-Mn under the influence of a forced flow field. The simulations are performed for isothermal conditions and the investigation concentrates on the effects of forced flow on the dendrite morphology during the growth dynamics. The effects of forced flow on microsegregation are also discussed.     

The magnetic anisotropy of MnF2 AT 0 K

The contributions that dipolar, single-ion and exchange anisotropy make to the perpendicular susceptibility χ?, the field H′_c for which ω↓ (k = 0) vanishes, and other properties of antiferromagnetic MnF₂ at T = 0 K are considered, first, i n the ionic approximation. A comparison of the calculated dipolar and single-ion anisotropy with the measured χ?, H′_c and magnon dispersion would seemingly require then the inclusion of an unreasonably large anisotropic exchange field H_AE = -0.9 kOe. However, an estimate of the effects that overlap and covalency have on the anisotropy reveals that much of the discrepancy between the results obtained from the point-dipolar, ionic approximation and the measured quantities is a consequence of the spatial redictribution of the cation magnetization onto the ligands.     

Analysis of low molecular weight aldehydes in air samples by capillary electrophoresis after derivatization with 4-hydrazinobenzoic acid

This work reports the analysis of selected aldehydes in air samples using capillary electrophoresis (CE). The method is based on the reaction of aldehydes with 4-hydrazinobenzoic acid (HBA) to give the corresponding hydrazones with maximum absorbance at 290 nm. Under optimized CE conditions, the HBA derivatives of four carbonyls (formaldehyde, acetaldehyde, propionaldehyde, and acrolein) were completely separated from one another, in less than 6 min, using a pH 9.3 tetraborate buffer at 0.040 mol L(-1) concentration as background electrolyte. A few method validation parameters were determined revealing good migration time repeatability (< 1.5% CV) and area repeatability (< 2% CV), excellent linearity (50-300 microg/L, r > 0.996) and adequate sensitivity for environmental applications. The limits of detection with respect to each single aldehyde were in the range of 2.7-8.8 ng L(-1). The methodology was applied to the determination of aldehydes indoors. Samples were collected in HBA impregnated octadecylsilica cartridges, at different times during the day. The most abundant carbonyls in the samples were acetaldehyde followed by formaldehyde, with estimated peak concentrations of 4.3 and 2.9 ppbv, respectively.     

A structure-activity study of antibacterial diterpenoids

An analysis of the antibacterial activities of 15 terpenoids, eleven of which were previously described by us and four were extracted from the literature, suggested two structural requirements for activity of these and related compounds: a hydrophobic moiety,consisting of a substituted decalin skeleton, and a hydrophilic region possessing one hydrogen-bond-donor group. These structural requirements are responsible for an optimal insertion of these and related compounds into cell membranes, as suggested by the results of docking some of these compounds into a model phospholipid bilayer.