Angular distributions of high energy protons channeled in long (10, 10) single-wall carbon nanotubes

In this work we study the angular distributions of 1 GeV protons channeled in long (10, 10) single-wall carbon nanotubes. The nanotube length, L, is varied between 10 and 100 μm. The angular distributions of channeled protons are obtained using the numerical solution of the proton equations of motion in the transverse plane and the Monte Carlo method. The effects of proton energy loss and scattering angle dispersion caused by its collisions with the nanotube electrons are taken into account. Analysis shows that for L < 30 μm, the transverse structure of the nanotube could be deduced from the angular distribution. For L ? 40 μm, the angular distribution contains the concentric circular ridges whose number increases and the average distance between them decreases when L increases. A possible application of the obtained results for characterization of carbon nanotubes is discussed.     

Spectral shaping of digitised speech for mobile radio applications

The modified duobinary technique is chosen for spectral shaping of digitised speech in mobile radio applications. A binary transversal filter coupled with a simple lowpass filter is used for generation of modified duobinary signals. The optimum value of the l.p. filter cutoff frequency is found using measured bit error rate curves and measured baseband power spectra.     

Therapy of Helicobacter pylori infection using Lactobacillus acidophilus

INTRODUCTION: In vitro experiments with Lactobacillus acidophilus have revealed its inhibitory effect on Helicobacter pylori and its application in treatment of Helicobacter pylori positive gastritis was examined. MATERIAL AND METHODS: 15 patients have undergone gastroscopy with biopsy and by histopathological examination. Helicobacter pylori positive gastritis was detected. During a two-month period these patients took acidophilus milk (3 x 250 ml a day) prepared according to a special protocol and which contained 4 x 10(9)-1 x 10(10) live cells of Lactobacillus acidophilus at the moment of preparation. Lactobacillus acidophilus strain NAS, gained from lyophilized preparation Bio-Nate (Natren Inc. USA) was used as a test organism. Control gastroscopy was performed 2 months later. RESULTS: 14 patients have completed the examination. All of them were satisfied with the taste of acidophilus milk and could stand it well, whereas in 6 out of 14 Helicobacter pylori was eradicated. DISCUSSION: Helicobacter pylori eradication therapy is recommended in all cases of Helicobacter pylori positive gastritis associated with peptic ulcer, as well as in absence of ulcer when subjective difficulties occur. Antibiotic therapy is often unsuccessful and most often associated with risks of significant adverse effects, being the consequence of intestinal microflora disorders. The aim of using Lactobacillus acidophilus in the therapy is to reduce risks of adverse effects. In our study, by using acidophilus milk only, without other therapy, eradication of Helicobacter pylori was achieved in 6 out of 14 patients. All patients could stand the therapy well and were satisfied with the taste of the preparation. The number of examinees was small in regard to making conclusions, but the results are encouraging and show that apart from established in vitro effect. Lactobacillus acidophilus has a potential in vivo effect.     

Determination of the photocatalytic efficiency of TiO2 coatings on ceramic tiles by monitoring the photodegradation of organic dyes

A method for the evaluation of the photocatalytic effectiveness of nanotitania coatings on ceramic substrate was established. Decolourization of three organic dyes, including methylene blue (MB), rhodamine B (RB) and crystal violet (CV), was investigated under different experimental conditions. The results showed that the UV light spectrum and light intensity are important parameters when establishing this method.The effect of TiO₂ on the percentage degradation of the dyes was examined by varying its concentration in the suspensions between 0.1% and 4.5 wt%, which resulted in different thicknesses of the TiO₂ layers, and as expected higher percentages of nanotitania resulted in higher photocatalytic efficiencies. However higher amounts of titania lead to the formation of cracks on the surface, which might detrimentally affect adhesion and thus also long-term durability. The applicability of all the dyes used in the present study was proved, and there is good correlation between MB, RB and CV in the evaluation of self-cleaning efficiency.     

Proton inactivation of melanoma cells enhanced by fotemustine

Response of human HTB140 melanoma cells to proton irradiation in combination with fotemustine (FM) was investigated. Effects of these agents were analysed on cell proliferation and induction of apoptosis. Cells pretreated with 100- or 250-μM of FM were irradiated in the middle of the therapeutic 62-MeV proton spread-out Bragg peak, with a dose of 16 Gy. All treatments reduced proliferation and survival of melanoma cells. The most pronounced effects of the combined treatment were obtained for cell survivals. The level of apoptosis increased after all applied treatments. Particularly good pro-apoptotic effect was achieved when proton irradiation was combined with 250 μM of FM. This was followed by the increased expression of p53 gene. The obtained results have shown that combined application of FM and protons significantly reduced growth of this resistant melanoma cell line.     

Laser-induced formation of intermetallics in multilayered Al/Ti nano-structures

In this study, multilayered structures consisting of eight (Al/Ti) bilayers deposited by d.c. ion sputtering onto Si (100) wafers, to a total thickness of ~300 nm were treated in air with a picosecond-pulsed Nd:YAG laser in a defocused regime. Irradiation was done with 200 successive pulses, at 1,064-nm wavelength, energy per pulse 15 mJ, the incidence angle of ~45°, covering an area of 2-mm in diameter. The samples were analyzed by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. It was found that laser irradiation-induced melting and a progressed Al–Ti nanoalloying within the top four bilayers (up to a depth of ~150 nm), while the underlying part of the multilayered structure remained intact. Another interesting result is that of a regularly rippled surface topography (~1.4-μm period and 100-nm amplitude) developed throughout the zone of the melted and reacted material.     

Influence of preparation methods on the properties of self-assembled films of octadecylphosphonate on Nitinol: XPS and EIS studies

The NiTi alloy (Nitinol), with its favorable micro-structured properties and self-passivity (resembling that of pure Ti) is used as an implant material for arterial stents and orthodontic wires. During the long term contact of the alloy with aggressive environment of human body, corrosion by releasing Ni^2 + ions can occur. Thus, the usefulness of such material can be dramatically enhanced if its interface structure and surface chemistry are controlled. The octadecylphosphonate interface (ODP) synthesis, which involves a self-assembled covalently (monodentate type) bonded film of octadecylphosphonic acid (ODPA) on the oxide covered NiTi surface, produces stable and corrosion resistant interfaces. This paper introduces integrated approach to the characterization of the NiTi/ODP interfacial architecture as well as the structure of the electrified ODP/solution interface using high-resolution XPS and in situ EIS measurements. The main focus of this work was to determine the influence of the ODPA deposition method (spray and immersion) on the depth-dependent structural characteristics and orientation of ODPA molecules in the surface film by means of angle resolved XPS. Mechanically strong and chemically stable NiTi/phosphonate interfaces have the potential for their successful implementation in stent technologies.     

Influence of substrate absorption on accuracy of determination of refractive index and thickness of uniform thin chalcogenide Cu1[As2(S0.5Se0.5)3]99 film

The envelope method is a commonly used method for determination of some important optical constants, by using the envelopes of the transmittance T(λ) and/or reflectance R(λ) spectrum of the thin film deposited on transparent substrate. Two envelope methods were carried out in this paper: standard—method which assumes that substrate is absolutely transparent and modified—method which takes substrate absorption into account.The investigated sample is a uniform thin chalcogenide Cu₁[As₂(S_0.5Se_0.5)₃]₉₉ film, deposited onto two kinds of a weakly absorbing substrates that differ in thickness.It was shown that the degree of accuracy in determination of chosen optical parameters for both investigated samples is notably improved when the absorbance of the bare substrates is considered in the expressions for the envelopes.     

Effect of Storage in a Low Oxygen Gas Atmosphere on Colour and Sensory Properties of Pork Loins

The objective of this study was to examine the quality characteristics of packaging materials and packaging units, and the viability and acceptability of the colour and sensorial properties of fresh pork meat during storage in low oxygen and high carbon dioxide modified atmosphere packaging up to 16 days at two temperatures (0°C and 4°C), as well as the sensorial properties of cooked meat. Packaging materials had good mechanical and barrier properties and were suitable for packaging in selected atmosphere. The concentration of oxygen during the whole storage period was less than 0.5% at both temperatures. The proportion of red colour (a*) was successfully maintained although the colour was slightly darker (L*) and the sensory value was lower when evaluated at the end of the storage period. Based on the obtained results and discussion, it can be concluded that samples packaged in a modified atmosphere with 40% CO₂ and 60% N₂ can be stored at 0°C for 15 days and at 4°C for 10 days. Samples had a good sensory quality until the 16th day, with the best results achieved on the 7th day. Copyright © 2013 John Wiley & Sons, Ltd.