Chemical and Sensory Characterization of Xinomavro Red Wine Using Grapes from Protected Designations of Northern Greece

Despite Xinomavro (Vitis vinifera L.) being a well-known noble red grape variety of northern Greece, little is known about its ''bouquet'' typicity. Volatile compounds of Xinomavro wines produced using a common vinification protocol were analyzed by gas chromatography-mass spectrometry and sensory descriptive analysis was carried out with a trained panel. Wines were characterized by the presence of fatty acids, ethyl and acetate esters, and alcohols, with contributions from terpenes and a volatile phenol. The most active aroma compounds were determined to be 3-methylbutyl acetate, β-damascenone, ethyl esters of octanoic and hexanoic acids, and eugenol. Those compounds positively correlated with fruity and spicy odor descriptors, with the wines being mostly characterized by five typical aroma terms: strawberry, berry fruit, spices, tomato, and green bell pepper. Partial least squares regression (PLSR) analysis was used to visualize relationship between the orthonasal sensory attributes and the volatile aroma compounds with calculated OAVs > 1. Key aroma-active volatiles in the wines were identified using GC-MS/olfactometry, providing a list of 40 compounds, among which 13 presented a modified detection frequency > 70%. This study is the first of its kind and provided strong indications regarding the aroma compounds defining the sensory characteristics of Xinomavro wines.

Impact of Assimilable Nitrogen Supplementation on Saccharomyces cerevisiae Metabolic Response and Aromatic Profile of Moschofilero Wine

The concentration of nitrogen in must is critical to yeast fermentation efficiency and wine aroma profile. The present work determined the effect of the amount of yeast assimilable nitrogen (YAN) on fermentation kinetics, aroma production, and gene expression patterns of the wine yeast Saccharomyces cerevisiae. Fermentations were performed under two different YAN concentrations of must. Acetate esters, linalool, and nerol appeared to be clearly affected by the different YAN levels. Real-time-PCR results revealed that the genes involved in ethyl and acetate esters production recorded, in general, higher transcript levels under high nitrogen supplementation. In addition, an up-regulation of the BGL2 and EXG1 genes, which are related to terpenes production, was observed in the case of high nitrogen content and it is well corresponded to the terpenol concentration found. Our study revealed the impact of nitrogen supplementation on yeast metabolism and its importance to adjust wine's aromatic composition and sensory profile.

Electromagnetic wave absorption properties of ternary poly(vinylidene fluoride)/magnetite nanocomposites with carbon nanotubes and graphene

Ternary nanocomposite systems of PVDF/Fe₃O₄/CNT and PVDF/Fe₃O₄/GN, prepared with twin screw compounding method, exhibit enhanced microwave absorption properties.

Correlation of interleukin-6 gene expression to immunologic features in patients with cardiac myxomas

Cardiac myxomas, the most common primary heart tumors in adults, show a variety of clinical manifestations and laboratory findings correlated with elevated interleukin-6 (IL-6) serum concentration. The aim of this study was to determine the expression of IL-6 mRNA in myxoma tissue as a cause to frequent immunologic abnormalities in patients with such tumors. In our centers, we analyzed 17 surgically resected myxomas using the polymerase chain reaction (PCR) and found increased IL-6 mRNA expression in 14 of 17 cases. The serum IL-6 levels of the 14 patients, detected by enzyme-linked immunosorbent assay (ELISA) with mouse antihuman monoclonal antibody (mAb), were high preoperatively (> 6 pg/ml) and decreased to normal postoperatively (< or = 6 pg/ml). These same 14 patients exhibited significant autoimmune disorders preoperatively. The other 3 patients had normal serum levels of IL-6 (< or = 6 pg/ml) and did not present any serious signs and symptoms, and molecular analysis did not show overexpression of IL-6 mRNA in neoplasmic tissue. These results suggest that IL-6 is overproduced in myxoma tissue and secreted into the systemic circulation as a stimulator of the immunoregulatory system. Furthermore, this study indicates the promising role of molecular biology techniques in the research of pathophysiologic mechanisms of cardiac myxomas.

Dielectric and conductivity studies of the hydration mechanisms in plant seeds

The hydration mechanism of various plant seeds has been investigated by a) sorption-desorption isotherms, b) ac-dielectric spectroscopy in the 10 Hz to 1 GHz frequency range and the -80 to + 40 degrees C temperature range, and c) thermally stimulated depolarization current techniques in the -170 to + 23 degrees C temperature range. Seeds of different chemical composition were studied at water contents varying between 0 and 40% w/w (dry weight basis). Our experimental results permitted us to determine i) the diffusion constant of water in the samples, found to be between 1.4 x 10(-11) and 3.7 x 10(-11) m2/s; ii) a critical water content corresponding to the completion of the primary hydration layer, which is in the range 0.11-0.17 w/w, depending on the seed nature; and iii) the activation energy of the main relaxation mechanism, found to be equal to 0.54 +/- 0.05 eV. Moreover, they make it possible to investigate the dependence of various parameters (conductivity, molecular mobility, plasticizing effect of water) on the water content of the sample, to follow the crystallization of water in the seeds as a function of temperature and confirm that it is not a reversible process, to study the dehydration process as a function of temperature and time, and to propose an alternative technique for the determination of the moisture content in seeds.