Raman spectra were measured for the full range of hole doping of the orthomanganites of the form La 1Ϫx Ca x MnO 3 (0рxр1) from ambient temperature to 75 K. Two high-frequency phonons that we assign to stretching modes of the oxygen atoms in the MnO 6 octahedra soften below the transition temperature to ferromagnetic insulator and disappear at a temperature that depends on the Ca concentration. The correlation of their properties with the lattice distortions is examined. At room temperature, and for xϳ0.35 and xϳ0.70, phonons attributed to the relative rotations of the octahedra show a strong correlation with the octahedral distortion and the reported low-temperature modifications of the magnetic properties of these compounds.

We report site-selective oxygen isotope ( 16 O/ 18 O) effect ͑OIE͒ measurements on the in-plane penetration depth ab in underdoped Y 0.6 Pr 0.4 Ba 2 Cu 3 O 7Ϫ␦ , using the muon-spin rotation technique. A pronounced OIE on the transition temperature T c as well as on ab Ϫ2 (0) was observed, which mainly arises from the oxygen sites within the superconducting CuO 2 planes ͑100% within error bar͒. The values of the corresponding relative isotope shifts were found to be ⌬T c /T c ϭϪ3.7(4)% and ⌬ ab Ϫ2 (0)/ ab Ϫ2 (0)ϭϪ6.2(1.0)%. Our results imply that in this compound the phonon modes involving the movement of planar oxygen are dominantly coupled to the electrons.

We report low-temperature and hydrostatic pressure Raman measurements in Pr 0.5 Ca 0.5 MnO 3 thin films grown on SrTiO 3 and LaAlO 3 substrates. From the low-temperature dependence of the modes related with the Jahn-Teller distortions of the octahedra, it is found that an increase appears in their relative intensities at temperatures close to the charge-ordering phase transition. Two rotational modes of vibration of the octahedra show an anharmonic behavior. Strains from the substrate do not induce any shift or new modes in the Raman spectra probably due to their relaxation from the interface towards the surface of the films. From the different orientation of the two films, the symmetry of certain modes has been identified.

In this study, the content composition and antioxidant activity of goji berry fruits from two species (Lycium barbarum and Lycium chinense) were assessed. The total carbohydrate and phenolic contents were evaluated using attenuated total reflection Fourier-transform infrared (ATR-FT-IR) spectroscopy, while the antioxidant activity of fruits was examined with two in vitro methods, which are based on the scavenging activity of the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2’-azino-bis(3-ethyl-benzthiazoline-sulfonic acid) (ABTS•+) free radicals. The fatty-acid profile was determined using gas chromatography coupled with mass spectrometry (GC-MS). The results of this study indicate that the fruits of L. barbarum present higher concentrations in carbohydrates and phenolics than L. chinense Mill. fruits. Furthermore, the antioxidant activity based on the half maximal inhibitory concentration (IC50) measurements of DPPH• and ABTS•+ free-radical scavenging was higher in L. barbarum than L. chinense Mill. Also, the GCMS analysis confirms the high levels of linoleic, palmitic, and oleic acids contained in the fruits of both species. Finally, the results of this study clearly show that the concentration of bioactive and antioxidant molecules is higher in L. barbarum than in L. chinense fruits, which was also confirmed by ATR-FT-IR measurements.

Silica nanoparticles were dispersed in an aqueous emulsion of alkoxy silanes and organic fluoropolymer. The dispersion was sprayed onto white marble and sandstone. The deposited composite coatings exhibited (i) superhydrophobicity and superoleophobicity, as evidenced by the high (>150°) static contact angles of water and oil drops as well as (ii) water and oil repellency according to the low (<7°) corresponding tilt contact angles. Apart from marble and sandstone, the coatings with extreme wetting properties were deposited onto concrete, silk, and paper, thus demonstrating the versatility of the method. The siloxane/fluoropolymer product was characterized using Fourier Transform Infrared Spectroscopy (FT-IR), Raman spectroscopy and Scanning Electron Microscopy equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDX). Moreover, SEM and FT-IR were used to reveal the surface structures of the composite coatings and their transition from superhydrophobicity to superhydrophilicity which occurred after severe thermal treatment. The composite coatings slightly reduced the breathability of marble and sandstone and had practically no optical effect on the colour of the two stones. Moreover, the coatings offered good protection against water penetration by capillarity.

We report boron isotope effect on the E 2g phonon mode by micro-Raman spectroscopy on the ternary Mg 1−x Al x B 2 system, synthesized with pure isotopes 10 B and 11 B. The isotope coefficient on the E 2g mode frequency is nearly 0.5 in the wide range of Al, with a tendency to decrease at MgB 2 ͑x =0͒. The intraband electron-phonon ͑e-ph͒ coupling relative to the sigma band has been extracted from the E 2g line-shape parameters. By tuning the Fermi energy near the electronic topological transition ͑ETT͒, where the sigma Fermi surface changes from two-dimensional to three-dimensional topology ͑in range 0 Ͻ x Ͻ 0.28͒, the E 2g mode shows the Kohn anomaly accompanied with a splitting into a hard and a soft component. The results suggest that the intraband hardly plays any role to control the high T c of Mg 1−x Al x B 2 The common physical features of diborides with the multigap FeAs-based superconductors and cuprates are discussed.

We study the hydrostatic pressure dependence of the Y123 lattice by synchrotron angle-dispersive powder diffraction up to 12.7 GPa in order to detect any lattice instabilities or phase separation observed by Raman measurements. In the pressure range (3.7 GPa < p < 10 GPa) mainly the c-axis (and to a smaller extend the a-, b-axis) undergoes a clear deviation from the expected equation of state. Upon the pressure release the data follow the anticipated dependence showing a strong hysteresis. At the pressure of ∼3.7 GPa new peaks appear in the diffraction patterns, which can be attributed to another apparently coherent phase that exhibits enhanced disorder and texture effects. The intensity of the new peaks decreases with increasing pressure and upon pressure release they disappear for p < 3.9 GPa. The in-plane Cu-O pl bonds, the Cu2-Cu1 distance and the fractional coordinate of Ba atom along the c-axis of the Y123 phase show modifications at characteristic pressures in complete agreement with the Raman measurements under pressure, strongly indicating a pressure-induced lattice instability and phase separation.

The interest in using plant by-product extracts as functional ingredients is continuously rising due to environmental and financial prospects. The development of new technologies has led to the achievement of aqueous extracts with high bioactivity that is preferable due to organic solvents nonuse. Recently, widely applied and emerging technologies, such as Simple Stirring, Pressure-Applied Extraction, Enzymatic Extraction, Ultrasound-Assisted Extraction, Pulsed Electric Fields, High Hydrostatic Pressure, Ohmic Heating, Microwave Assistant Extraction and the use of “green” solvents such as the deep eutectic solvents, have been investigated in order to contribute to the minimization of disadvantages on the extraction of bioactive compounds. This review is focused on bioactive compounds derived from pomegranate (Punica granatum) peels and highlighted the most attractive extraction methods. It is believed that these findings could be a useful tool for the pomegranate juices industry to apply an effective and economically viable extraction process, transforming a by-product to a high added value functional product.