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Ground fennel seeds were extracted with supercritical carbon dioxide. Small-scale subsequent extractions of the same sample showed that the composition of volatile compounds was changed with the extension of extraction time and only principal volatile components (limonene, fenchone, methylchavicol, and anethole) were present in the last-extracted sample.(More)
Extraction of pigments (chlorophylls and carotenoids) from marjoram (Origanum majorana L.) with supercritical carbon dioxide was investigated. The aim of this study was to map the effects of extraction pressure and temperature on the yield of coloring materials by applying a 3(2) full factorial design with three repeated tests in the center of the design.(More)
We explore a new application of optical tweezers for ultrasensitive detection of sound waves in liquid media. Position tracking of a single gold nanoparticle confined in a three-dimensional optical trap is used to readout acoustic vibrations at a sound power level down to -60  dB, causing a ∼90  μeV increase in kinetic energy of the nanoparticle. The(More)
The validity of various effective medium approximations (EMAs) (Bruggeman, Maxwell-Garnett) was studied for nanostructured systems, where the scale of inhomogeneities is comparable to the wavelength. Langmuir-Blodgett (LB) layers of Stöber silica nanospheres of diameters between 40 and 129 nm are excellent model structures for the experimental verification(More)
We present the studies on the structure and optical properties of bidisperse Stöber silica nanoparticulate Langmuir films prepared at the air/water interface in a Wilhelmy film balance and transferred onto glass slides using the Langmuir-Blodgett technique. Three different compositions (covered area ratios: 4:1; 1:1, and 1:4) of two bidisperse systems were(More)
Stöber silica nanoparticles of diameter about 45, 60 and 100 nm and different hydrophobicity are used to produce monolayers at a water-air interface. Both the surface pressure-area isotherms and the reflectivity angle of incidence curves of the layers have been measured in a Wilhelmy film balance. The contact angle of the as-prepared particles have been(More)
Graphene covered metal nanoparticles constitute a novel type of hybrid material, which provides a unique platform to study plasmonic effects, surface-enhanced Raman scattering (SERS), and metal-graphene interactions at the nanoscale. Such a hybrid material is fabricated by transferring graphene grown by chemical vapor deposition onto closely spaced gold(More)
The current state of the art in the use of colloidal methods to form nanoparticle assemblies, or clusters (NPCs) is reviewed. The focus is on the two-step approach, which exploits the advantages of bottom-up wet chemical NP synthesis procedures, with subsequent colloidal destabilization to trigger assembly in a controlled manner. Recent successes in the(More)
Microfluidic jetting is a promising method to produce giant unilamellar phospholipid vesicles for mimicking living cells in biomedical studies. We have investigated the chemical composition of membranes of vesicles prepared using this approach by means of Raman scattering spectroscopy. The membranes of all jetted vesicles are found to contain residuals of(More)
Levente Rózsa,1,* Krisztián Palotás,2,3 András Deák,2,4 Eszter Simon,2 Rocio Yanes,5 László Udvardi,2,4 László Szunyogh,2,4 and Ulrich Nowak6 1Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary 2Department of Theoretical Physics, Budapest University of(More)