Impact of e-cigarette liquid on porcine lung tissue-Ex vivo confocal Raman micro-spectroscopy study

Ex vivo porcine lung immersed in e-liquid was investigated in-depth using confocal Raman micro-spectroscopy to assess the e-liquid influence on the lung. It was found that lung-related Raman band intensities at 1002, 1548, 1618 and 1655 cm-1 increased after first and second treatments except the surface, which was attributed to the well-known optical clearing (OC) effect due to alveoli filling with e-liquid resulting in light scattering reduction. The autofluorescence enhancement was explained by oxidative stress induced in lung during exposure to e-liquid. Moreover, e-liquid induced collagen dehydration was revealed by the I937 /I926 Raman band intensity ratio change. The effect was enhanced after the second treatment of the same lung tissue that indicates the possibility of multi-step OC treatment. We hypothesize that the nicotine-flavour-free e-liquids containing glycerol and propylene glycol could potentially be used in clinical protocols as OC agent for enhanced in-depth Raman-guided bronchoscopy.

Preparation and Characterization of Perforated SERS Active Array for Particle Trapping and Sensitive Molecular Analysis

A gold-coated array of flow-through inverse pyramids applicable as substrate for entrapment and immobilization of micro-objects and for surface enhanced Raman spectroscopic measurements was fabricated using bulk micromachining techniques from silicon. Surface morphology, optical reflectance, immobilization properties, and surface enhanced Raman amplification of the array were modelled and characterized. It was found that the special perforated periodic 3D structure can be used for parallel particle and cell trapping and highly sensitive molecular analysis of the immobilized objects.

Fusiform vateritic inclusions observed in European eel (Anguilla anguilla L.) sagittae

Microscopic inclusions have been observed in 7 out of 106 European eel (Anguilla anguilla L.) sagittae using polarizing microscope and scanning electron microscope meanwhile the annual increments were studied to characterize the age structure of the population living in Lake Balaton. The presence of vaterite, a rare calcium carbonate polymorph was observed in these inclusions using Raman spectroscopy. Vateritic sagittae in wild fish are usually considered as symptom of physiological stress. The observed fusiform inclusions represent a new morphological type of vaterite inclusions in eel otolith. Two alternatives are hypothesized to explain their formation: 1) metabolic disorder, such as erroneous protein synthesis; 2) introduction of an alien protein into the eel's inner ear. The origin and physiological significance of this new morphological type of vateritic inclusions is still an open question. Same as whether it can be found in other species or specific only to eel otoliths.

A new, simple approximation for the deconvolution of instrumental broadening in spectroscopic band profiles

A robust empirical correction formula has been developed for the approximation of Lorentzian widths, using a known spectrometer bandpass, in instrument-broadened Voigt bands in optical spectra. The relationship between analytically calculated [(w(Voigt) - w(Lorentz))/w(Gauss)] and [w(Voigt)/w(Gauss) - 1] values (where w is the full width at half-maximum [FWHM]) is analyzed to derive the formula for the approximation of the (w(Voigt) - w(Lorentz)) difference. The precision of the method is demonstrated by comparing its performance to several previously published numerical correction approaches. The fraction of the Lorentzian contribution in Voigt FWHMs is evaluated in terms of the Gaussian FWHM to assess the conditions under which the deconvolution of instrumental broadening is necessary.

Interactions and chemical transformations of coronene inside and outside carbon nanotubes

By exposing flat and curved carbon surfaces to coronene, a variety of van der Waals hybrid heterostructures are prepared, including coronene encapsulated in carbon nanotubes, and coronene and dicoronylene adsorbed on nanotubes or graphite via π-π interactions. The structure of the final product is determined by the temperature of the experiment and the curvature of the carbon surface. While at temperatures below and close to the sublimation point of coronene, nanotubes with suitable diameters are filled with single coronene molecules, at higher temperatures additional dimerization and oligomerization of coronene occurs on the surface of carbon nanotubes. The fact that dicoronylene and possible higher oligomers are formed at lower temperatures than expected for vapor-phase polymerization indicates the active role of the carbon surface used primarily as template. Removal of adsorbed species from the nanotube surface is of utmost importance for reliable characterization of encapsulated molecules: it is demonstrated that the green fluorescence attributed previously to encapsulated coronene is instead caused by dicoronylene adsorbed on the surface which can be solubilized and removed using surfactants. After removing most of the adsorbed layer, a combination of Raman spectroscopy and transmission electron microscopy was employed to follow the transformation dynamics of coronene molecules inside nanotubes.