The solid‐state 2:1 molecular complex of 1,5:3,7‐dimethano‐1,3,5,7‐benzotetrazonine with hydroquinone

The title compound, 1,5:3,7‐dimethano‐1,3,5,7‐benzotetrazonine–hydroquinone (2/1), 2C₁₁H₁₄N₄·C₆H₆O₂, crystallizes with the hydroquinone molecule located on a center of inversion. In contrast to other hydroquinone–adamanzane adducts, which form extended hydrogen‐bonded networks, in the present case, one hydroquinone molecule is linked to two 1,5:3,7‐dimethano‐1,3,5,7‐benzotetrazonine molecules, forming a 2:1 cluster through O—H...N hydrogen bonds.     

Peagol and peagoldione, two new strigolactone-like metabolites isolated from pea root exudates

Two new strigolactone-like metabolites, named peagol and peagoldione, with germinative activity for root parasitic plants, were isolated from pea root exudates and were characterized by spectroscopic methods. Peagol was more active on Orobanche foetida and Phelipanche aegyptiaca seeds, while peagoldione was active on P. aegyptiaca only. Low activity was found on Orobanche crenata and Orobanche minor. Stimulatory activity of peagol on O. foetida seeds is most relevant as this species does not respond to the synthetic strigolactone analogue GR24, usually used as Orobanche germination standard.     

Curcuminoid-phospholipid complex induces apoptosis in mammary epithelial cells by STAT-3 signaling

Curcumin (from the rhizome of Curcuma longa) is well documented for its medicinal properties in Indian and Chinese systems of medicine where it is widely used for the treatment of several diseases. Epidemiological observations are suggestive that curcumin consumption may reduce the risk of some form of cancers and provide other protective biological effects in humans. These biological properties have been attributed to curcuminoids that have been widely studied for their anti-inflammatory, anti-angiogenic, antioxidant, wound healing and anti-cancer effects. In this study we have investigated on the effect of a curcumin phospholipid complex on mammary epithelial cell viability. HC11 and BME-UV cell lines, validated models to study biology of normal, not tumoral, mammary epithelial cells, were used to analyse these effects. We report that curcumin acts on STAT-3 signal pathway to reduce cell viability and increase apoptosis evaluated by the the amount of activated caspase 3. Further it reduces MAPK and AKT activations. JSI-124, a STAT-3 inhibitor (100 nM) was able to block the negative effect of curcumin on cell viability and caspase 3 activation. Finally the negative effect of cucumin on cell viability has been impaired in STAT-3ⁱ HC11, where STAT-3 protein was greatly reduced by shRNA-interference. These results indicate that curcumin presents a potential adverse effect to normal mammary epithelial cells and that it has a specific effect on signal trasduction in mammary epithelium.     

Temperature dependence on phase evolution in the BaTiO3 polytypes studied using ab initio calculations

Identifying the forces that drive a temperature-induced phase transition is always challenging in the prospect of the first-principles methods. Herein, we perform a first-principles study of the temperature effects on structural, energetic, electronic, and vibrational properties of four BaTiO₃ polymorphs using quasi-harmonic approximations. Study of the stability between these four phases, which we break into contributions arising from the vibration of the lattice, electronic structure, and volume expansion/contraction, is helpful to confirm the sequence of phase transitions as cubic → tetragonal → orthorhombic → rhombohedral, as well as its transition temperatures. A general mechanism was proposed based on the combination between structural distortions at [TiO₆] clusters, vibrational characteristics, and electronic structure. These findings confirm the power of quasi-harmonic approximations to disclose the main fingerprints associated with both thermic and mechanical phase transitions, serving as a guide for further theoretical studies.     

Synthesis,characterization and in vitro antimicrobial prospecting of silver-doped ceria

Journal of Thermal Analysis and Calorimetry - In this work, Ag-doped CeO2 samples containing 0.5 mol% Ag+ were successfully synthesized by the polymeric precursor method and then calcined...     

EXAFS of Cd1−xZnxTe: A test of the random distribution in zincblende ternary alloys

We report EXAFS measurements above the L_III edge of Te in Cd_1?x Zn_xTe for five compositions x. We find that the distribution of near-neighbours is bimodal, as in other II–VI zincblende ternary alloys. This behaviour is predicted by a model based on a random distribution of cations on a fcc sublattice and a highly distorted fcc sublattice for anions. The distribution of second neighbours is apparently bimodal, but a closer analysis reveals that this distribution is actually multimodal.     

M-Methods in multivariate linear models

For the multivariate linear model, coordinatewise M-estimators as well as an extension of the Maronna-type M-estimators are considered. Based on the Jure?ková (asymptotic) linearity of M-statistics, the asymptotic distribution theory of the proposed estimators is studied under appropriate regularity conditions, and incorporated in the formulation of some (asymptotic) M-tests of linear hypotheses. Finally, robustness properties of both types of estimators are discussed.     

Shape fluctuations of large unilamellar lipid vesicles observed by laser light scattering: influence of the small-scale structure

In the present paper, we apply the dynamic laser light scattering technique to investigate the dependence of the characteristic times of thermally induced shape fluctuation of large unilamellar vesicles (LUVs) on bilayer composition. After addressing single-component LUVs made of two common phospholipids, dimyristoylphosphatidylcholine (DMPC) and dipalmitoylphosphatidylcholine (DPPC), we investigate the changes in vesicle shape fluctuation times due to the presence of cholesterol and gangliosides (GM1), added in small amounts. The experimental results show that the addition of a second component, even in small amount, to DMPC vesicles induces a change in membrane fluctuation times. Moreover, in the case of ganglioside addition, also the disposition of GM1 within the bilayer is of importance. Quite unexpectedly, the symmetric or asymmetric disposition of GM1 has opposite effects on bilayer dynamics, the first resulting in a "hardening" and the second in a "softening" of the membrane. Those results support that the small-scale structure of the bilayer is important in determining the overall dynamics of the vesicle. They also suggest that the physiological disposition of GM1 in the outer leaflet of real cells has a significative result in mechanical terms, positively affecting the dynamics of the membrane.     

Addition of carbamoylsilanes to electrophilically substituted alkenes. Preparation of beta-functionalized tertiary amides

The Si-C bond of N,N-dimethylcarbamoylsilanes added regiospecifically to the C=C bond of electrophilically functionalized alkenes to afford beta-silyl-beta-functionalized amides. Carbonyl addition products were formed when hindered alkenic esters were used. [reaction: see text]     

Synthesis of novel pyrido[3′,2′:5,6]thiopyrano[3,2‐b]indol‐5(6H)‐ones and 6H‐pyrido[3′,2′:5,6]thiopyrano[4,3‐b]quinolines,two new heterocyclic ring systems

The synthesis of new pyrido[3′,2′:5,6]thiopyrano[3,2‐b]indol‐5(6H)‐ones was accomplished by the Fischer‐indole cyclization of some 2,3‐dihydro‐3‐phenylhydrazonothiopyrano[2,3‐b]pyridin‐4(4H)‐ones, obtained from the 2,3‐dihydro‐3‐hydroxymethylenethiopyrano[2,3‐b]pyridin‐4(4H)‐one, by the Japp‐Klingemann reaction. 6H‐Pyrido[3′,2′:5,6]thiopyrano[4,3‐b]quinolines were obtained by reaction of 2,3‐dihydrothiopyrano‐[2,3‐b]pyridin‐4(4H)‐ones with o‐aminobenzaldehyde or 5‐substituted isatins. The preparation of some derivatives, functionalized with an alkylamino‐substituted side chain, is also described.