Comparison of the characterisation of the fruit‐like aroma of Teucrium flavum L. subsp flavum by hydrodistillation and solid‐phase micro‐extraction

BACKGROUND: Teucrium species (Lamiaceae) are interesting for the food industry since many of them are used in the preparation of flavoured wines and beers, herbal teas, bitters and liqueurs. On this basis, the analysis of the aroma components of Teucrium flavum L. subsp. flavum growing in central Italy was carried out by means of both hydrodistillation (HD) and headspace solid‐phase micro‐extraction (HS‐SPME), coupled with GC/FID and GC/MS. RESULTS: A total of 102 components were identified in the essential oils, representing 99.0‐99.3% of the total oils. Sesquiterpenes hydrocarbons constituted the major fraction (48.5–49.4%), with the apple‐like flavour (Z,E)‐α‐farnesene being the major component. HS‐SPME allowed the analysis of the volatiles not only emitted by specific plant parts, but also by different parts within a single flower: flower calyx afforded the highest contribution, in terms of volatiles, to the aroma of the plant. CONCLUSION: The chemical profile of the volatile fraction obtained by HD and HS‐SPME, demonstrated the plant fruit‐like aroma, confirming the usefulness for flavouring wines, bitters and other kind of beverages, and also suggested other applications, as aroma and taste enhancer in food processing. In particular, SPME resulted in a very useful technique, which permits a choice between the part of the plant which has the highest concentration of a specific fragrance, and therefore establishes the best way of sampling during industrial applications of aromatic plants. Copyright © 2009 Society of Chemical Industry     

A versatile high-permittivity phantom for EIT

Phantoms are frequently used in medical imaging systems to test hardware, reconstruction algorithms, and the interpretation of data. This report describes and characterizes the use of powdered graphite as a means of adding a significant reactive component or permittivity to useful phantom media for electrical impedance imaging. The phantom materials produced have usable complex admittivity at the electrical impedance tomography (EIT) frequencies from a few kilohertz to 1 MHz, as measured by our EIT system (ACT4) and by a commercial bioimpedance analyzer (BIS 4000, Xitron). We have also studied a commercial ultrasound coupling gel, which is highly electrically conductive and semisolid but that permits objects to move within it. The mixture of agar–graphite and gel–graphite, increases in permittivity and conductivity are proportional to the graphite concentration. We also report the use of a porous polymer membrane to simulate skin. A thin layer of this membrane increased resistance and the characteristic frequency of the phantoms, providing a promising candidate to simulate the effect of skin and the layered structure of a breast or other anatomical structure. The graphite also provides a realistic level of “speckle” in ultrasound images of the phantom, which may be useful in developing dual-mode imaging systems with ultrasound and the EIT.      

The monolithic multicell: a tool for testing material components in dye‐sensitized solar cells

A multicell is presented as a tool for testing material components in encapsulated dye‐sensitized solar cells. The multicell is based on a four‐layer monolithic cell structure and an industrial process technology. Each multicell plate includes 24 individual well‐encapsulated cells. A sulfur lamp corrected to the solar spectrum has been used to characterize the cells. Efficiencies up to 6·8% at a light‐intensity of 1000 W/m^su2 (up to 7·5% at 250 W/m²) have been obtained with an electrolyte solution based on γ‐butyrolactone. Additionally, a promising long‐term stability at cell efficiencies close to 5% at 1000 W/m² has been obtained with an electrolyte based on glutaronitrile. The reproducibility of the cell performance before and after exposure to accelerated testing has been high. This means that the multicell can be used as an efficient tool for comparative performance and stability tests. Copyright © 2006 John Wiley & Sons, Ltd.     

1D-photonic crystals prepared from the amorphous chalcogenide films

We describe the preparation and optical properties of the 15-layer chalcogenide dielectric mirrors with the first order stop bands in near infrared range. The high refractive index Sb–Se and low refractive index Ge–S layers were deposited on silicon and glass substrates using thermal evaporation method. To centre the stop bands of the prepared chalcogenide mirrors at 1.55 μm, the layer thicknesses, d(Sb–Se) = 117 and d(Ge–S) = 183 nm, were calculated from the quarter wave stack condition. The optical reflectivity measurements revealed the total reflection from the 15-layer chalcogenide mirrors in the range of 1,400–1,600 nm for the unpolarized light with normal incidence. The effect of annealing on the optical properties of the prepared chalcogenide mirrors was studied as well. Using spectral ellipsometry, we examined the angular dependence of the multilayers reflectivity for the light with s- and p-polarization. The preparation of the dielectric mirrors for near infrared region from chalcogenide films seems to be possible exploiting good optical quality of chalcogenide films and their simple deposition.     

Interactions between human neutrophils and mucin-coated surfaces

Recently, we showed microscopically that bovine (BSM), porcine (PGM) and human (MG1) mucin coatings could suppress the adhesion of neutrophils to a polyethylene terephthalate-based model biomaterial (Thermanox). Here, using the release of reactive oxygen species (ROS) as a marker of material-induced neutrophil activation, the strong surface-passivating effects of these mucin coatings were corroborated. Under optimal adsorption conditions, all mucin species performed equally well, thus indicating a high degree of functional homology between the mucins. Cell adhesion and morphology correlated well with the release of ROS. Quartz crystal microbalance (QCM-D) analysis linked low neutrophil activation to efficient mucin surface-shielding. Interestingly, the shielding power appeared equal for thick expanded and thin compact mucin coatings. Combined mucin-serum coatings were found to be highly surface-passivating. Particularly, since our data suggested partly synergistic mucin-serum action, we highlight the possibility that pre-adsorbed mucins could provide favorable support for adsorbing host components.     

Conventional and wavelet coherence applied to sensory-evoked electrical brain activity

The use of coherence is a well-established standard approach for the analysis of biomedical signals. Being entirely based on frequency analysis, i.e., on spectral properties of the signal, it is not possible to obtain any information about the temporal structure of coherence which is useful in the study of brain dynamics, for example. Extending the concept of coherence as a measure of linear dependence between realizations of a random process to the wavelet transform, this paper introduces a new approach to coherence analysis which allows to monitor time-dependent changes in the coherence between electroenecphalographic (EEG) channels. Specifically, we analyzed multichannel EEG data of 26 subjects obtained in an experiment on associative learning, and compare the results of Fourier coherence and wavelet coherence, showing that wavelet coherence detects features that were inaccessible by application of Fourier coherence.     

Predictors of driving after alcohol and drug use among adolescents in Valencia (Spain)

Background

Driving under the influence of alcohol and drugs has been identified as a risk factor for road traffic crashes. We have assessed the prevalence and predictor factors for driving after alcohol and drug use by adolescents.

Methods

A cross-sectional survey involving 11,239 students aged 14–18 years from 252 private and public schools in the Valencia region of Spain was conducted. The prevalence and predictors of driving after alcohol use, alcohol and drug use, or drug use during the previous 6 months were measured.

Results

Of the students who reported driving (20%), 45.1% indicated driving after alcohol and drug use. The consumption of various drugs was higher among students who drove a vehicle compared with those who did not. The likelihood of driving after consuming alcohol, or alcohol and drugs, increased in line with the number of standard drink units per week, reports of any lifetime alcohol- or drug-related problems, and poor family relationship. In addition, masculine gender and early alcohol use increased the likelihood of driving after consuming alcohol.

Conclusions

Driving after alcohol and drug use is quite prevalent among adolescents in the Valencia region of Spain. There is a need for implementation of targeted policies for adolescents. This should focus on education and information on alcohol/drug use and driving.     

Aggregation Condition–Structure Relationship of Mouse Prion Protein Fibrils

Prion diseases are associated with conformational conversion of cellular prion protein into a misfolded pathogenic form, which resembles many properties of amyloid fibrils. The same prion protein sequence can misfold into different conformations, which are responsible for variations in prion disease phenotypes (prion strains). In this work, we use atomic force microscopy, FTIR spectroscopy and magic-angle spinning NMR to devise structural models of mouse prion protein fibrils prepared in three different denaturing conditions. We find that the fibril core region as well as the structure of its N- and C-terminal parts is almost identical between the three fibrils. In contrast, the central part differs in length of β-strands and the arrangement of charged residues. We propose that the denaturant ionic strength plays a major role in determining the structure of fibrils obtained in a particular condition by stabilizing fibril core interior-facing glutamic acid residues.     

High-speed, high-resolution monolithic capillary LC-MALDI MS using an off-line continuous deposition interface for proteomic analysis

High-speed, high-resolution LC separations, using a poly(styrene-divinylbenzene) monolithic column, have been coupled to MALDI MS and MS/MS through an off-line continuous deposition interface. The LC eluent was mixed with alpha-cyano-4-hydroxycinnamic acid matrix solution and deposited on a MALDI plate that had been precoated with nitrocellulose. Deposition at subatmospheric pressure (80 Torr) formed a 250-microm-wide serpentine trace with uniform width and microcrystalline morphology. The deposited trace was then analyzed in the MS mode using a MALDI-TOF/TOF MS instrument. Continuous deposition allowed interrogation of the separation with a high data sampling rate in the chromatographic dimensions, thus preserving the high resolution of narrow peaks (3-5-s peak width at half-height) of the fast monolithic LC. No extracolumn band broadening due to the deposition process was observed. Over 2000 components were resolved in a 10-min linear gradient separation of the model sample, and 386 unique peptides were identified in the subsequent MS/MS analysis. The continuous deposition interface allows the coupling of high-resolution separations to MALDI MS without degradation in separation efficiency, thus enabling high-throughput proteome analysis.     

Modeling adsorption-desorption processes of Cu on edge and planar sites of montmorillonite

The effect of the ionic strength on adsorption of Cu on calcium montmorillonite was studied at concentrations ranging from 31 to 516 microM. An adsorption model was employed in the analysis of the data. When the background electrolyte was NaClO4, the ionic exchange was suppressed at 0.5 M concentration, and Cu adsorption took place on edge sites, reaching a plateau at about 24 mmol/kg. A further increase in ionic strength did not have any effect on Cu adsorption, suggesting that the heavy metal was adsorbed by inner-sphere complexes on the edge sites of the clay. A binding coefficient for Cu2+ on the edge sites K = 2 x 10(4) M(-1) was determined, indicating very high affinity of Cu2+ for these sites. When the electrolyte used was NaCl, the amounts of Cu adsorbed were reduced. The model predicted well the adsorption data by considering the adsorption of CuCl+ species. Adsorption-desorption processes of Cu on calcium montmorillonite in media of 0.01 and 0.1 M NaCl showed hysteresis. Model calculations also predict the desorption fairly well. According to the model, the hysteresis is mainly attributed to the heterogeneity of sites for the adsorption of Cu. The hysteresis arising from the planar sites is largely due to reduced competition of ion species for adsorption and enhancement in the magnitude of the surface potential.