Magnetic fluid poly(ethylene glycol) with moderate anticancer activity

Poly(ethylene glycol) (PEG)-containing magnetic fluids - magnetite (Fe₃O₄) stabilized by sodium oleate - were prepared. Magnetic measurements confirmed superparamagnetic behaviour at room temperature. The structure of that kind of magnetic fluid was characterized using different techniques, including electron microscopy, photon cross correlation spectroscopy and small-angle neutron scattering, while the adsorption of PEG on magnetic particles was analyzed by differential scanning calorimetry and Fourier transform infrared spectroscopy. From the in vitro toxicity tests it was found that a magnetic fluid containing PEG (MFPEG) partially inhibited the growth of cancerous B16 cells at the highest tested dose (2.1 mg/ml of Fe₃O₄ in MFPEG).     

Luminance adaptation model for increasing the dynamic range of an imaging system based on a CCD camera

We propose a luminance adaptation model (LAM) to increase the dynamic range of an imaging system when scenes containing areas of low and high illumination are imaged. The LAM that we developed is based on capturing images at different exposure times to obtain digital levels within the linear response zone for all the pixels in the image. The levels are subsequently transformed to a reference exposure time that is common to all pixels. We use a linear transformation whose coefficients are determined by the digital levels obtained for a set of flat-spectrum samples. In this study, the LAM is applied to a multispectral imaging system that is based on a CCD camera used for color measurements and spectral reconstructions. It is shown to be a very useful method for increasing the dynamic range of the system, whilst maintaining its accuracy.     

Raman spectroscopic probing of plant material using SERS

We report surface‐enhanced Raman studies on intact plant material using onion layers as a biological target, and silver nanoaggregates and silver island films as enhancing plasmonic structures. Surface‐enhanced Raman scattering (SERS) enhancement allows the detection of strong Raman signatures of chemical constituents of the surface of the onion layer such as cellulose, proteins, and flavonols. Because of long‐time incubation, SERS sensors can access the extracellular space in the inner of the layer. The location of silver nanoparticles inside the onion layer has been monitored by the SERS images collected from chemicals present in the onion and/or reporter molecules attached to the nanoparticles. Our studies show a competitive adsorption of intrinsic bio molecules of the onion layer and reporter molecules. Different spectra from different places of the layer indicate the complex heterogeneous chemical structure of the plant material. The pH‐sensitive reporter molecule para mercapto benzoic acid attached to the nanoparticles allows us to infer pH values inside the extracellular matrix of the onion layer. Copyright © 2015 John Wiley & Sons, Ltd.     

Influence of atmospheric refraction on the performance of an outdoor ultrasonic pulse compression system

Nowadays, many ultrasonic sensory systems are being developed to operate outdoors, where they are finding a variety of applications, such as local positioning, vehicle navigation or obstacle detection. To assure the reliable operation of these systems under any meteorological condition, it is necessary to achieve a thorough comprehension of the effects that the different atmospheric phenomena can have on the propagation of these acoustic waves. This paper deals with one of these phenomena, atmospheric refraction, and its influence on the performance of an ultrasonic system whose signals are detected by matched filtering.     

Sonochemical degradation of triclosan in water and wastewater

The sonochemical degradation of 5 μg l⁻¹ triclosan, a priority micro-pollutant, in various environmental samples (seawater, urban runoff and influent domestic wastewater) as well as in model solutions (pure and saline water) was investigated. Experiments were conducted with a horn-type sonicator operating at 80 kHz frequency and a nominal applied power of 135 W, while solid-phase microextraction coupled with gas chromatography–electron capture detector (SPME/GC–ECD) was employed to monitor triclosan degradation. The latter followed pseudo-first order kinetics with the rate constant being (min⁻¹): 0.2284 for seawater > 0.1051 for 3.5% NaCl in deionised water > 0.0597 for centrifuged urban runoff  0.0523 for untreated urban runoff > 0.0272 for deionised water > 0.0063 for wastewater influent. SPME/GC–ECD and SPME coupled with gas chromatography–mass spectrometry (SPME/GC–MS) were also used to check for the formation of chlorinated and other toxic by-products; at the conditions in question, the presence of such compounds was not confirmed.     

Experimental and kinetic modeling study of oxidation of acetonitrile

Oxidation of acetonitrile has been studied in a flow reactor in the absence and presence of nitric oxide. The experiments were conducted at atmospheric pressure in the temperature range 1150–1450 K, varying the excess air ratio from slightly fuel-lean to very lean. Oxidation of CH₃CN was slow below 1300 K. Nitric oxide, hydrogen cyanide and nitrous oxide were detected as important products. A detailed chemical kinetic model for oxidation of acetonitrile was developed, based on a critical evaluation of data from literature. The rate coefficients for the reactions of CH₃CN and CH₂CN with O₂ were calculated from ab initio theory. Modeling predictions were in satisfactory agreement with experiments. Calculations were sensitive to thermal dissociation of CH₃CN and to the branching fraction for CH₃CN + OH to CH₂CN + H₂O and HOCN + CH₃, respectively. More work is desirable for these steps, as well as for reactions of CH₂CN and HCCN.     

Effects of mobile phone exposure on time frequency fine structure of transiently evoked otoacoustic emissions

Mobile phones have become very commonly used worldwide within a short period of time. To date there is only limited knowledge about interaction between electromagnetic fields (EMFs) emitted by mobile phones and the auditory function. Moreover, there is widespread concern that there may be potential for harm. The aim of this study was to assess potential subtle changes in cochlear function by measuring the temporal and spectral fine structure of transiently evoked otoacoustic emissions (TEOAE) in normal hearing subjects after exposure to EMFs emitted by Global System for Mobile Communication (GSM) mobile phones. TEOAEs were recorded in 27 healthy young adults before and after 10 min of real or sham exposure in a double-blind design. TEOAE data were analyzed both globally (broadband analysis) and using the Wavelet Transform (analysis of the time-frequency fine structure). The broadband analysis revealed no significant effect on TEOAEs related to exposure, confirming results of previous studies; in addition, no significant change was detected in the analysis of the elementary wavelet components, suggesting that the temporal and spectral fine structure of TEOAEs is not affected by 10 min exposure to low-intensity EMFs emitted by GSM mobile phones.     

Effects of electron-beam irradiation on surface oxidation of polymer composites

The aim of this article was to show the effects of an electron radiation dose and presence of a compatibilizer on the oxidation of composites made of blends of low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), and poly(ethylene terephthalate) (PET) as well as of blends of LDPE, HDPE, and PP. As the compatibilizers, the styrene-ethylene/butylene-styrene elastomer grafted with maleic anhydride (SEBS-g-MA) and trimethylol propane trimethylacrylate (TMPTA) were used; they were added in the amounts of 5, 10, and 15 wt% and 1, 2, and 3 wt%, respectively. The oxidation of the surface layer (SL) was investigated by the X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). It was found that the extent of the composite oxidation increased with the increasing dose of the electron radiation. The addition of the compatibilizers enhanced the oxidation of the SL but hindered the oxidation of the bulk of the material.     

Ultrasonic monitoring of malolactic fermentation in red wines

The progress of malolactic fermentation in red wines has been monitored by using ultrasonic techniques. The evolution of ultrasonic velocity of a tone burst 1 MHz longitudinal wave was measured, analyzed and compared to those parameters of oenological interest obtained simultaneously by analytical methods. Semi-industrial tanks were used during measurements pretending to be in real industrial conditions. Results showed that the ultrasonic velocity mainly changes as a result of the conversion by lactic acid bacteria of malic acid into lactic acid and CO₂. Overall, the present study has demonstrated the potential of the ultrasonic technique in monitoring the malolactic fermentation process.