Qualitative and quantitative evaluation of heart sound reduction from lung sound recordings

Recursive least squares (RLS) adaptive noise cancellation (ANC) and wavelet transform (WT) ANC have been applied and compared for heart sound (HS) reduction from lung sounds (LS) recordings. Novel processes for quantitative and qualitative evaluation of any method for HS reduction from LS have also been proposed.     

Polyamine deactivation of integrated poly(dimethylsiloxane) structures investigated by radionuclide imaging and capillary electrophoresis experiments

The poly(dimethylsiloxane) (PDMS) material provides a number of advantageous features, such as flexibility, elasticity, and transparency, making it useful in integrated analytical systems. Hard fused-silica capillary structures and soft PDMS channels can easily be combined by a tight fit, which offers many alternatives for structure combinations. PDMS and fused silica are in different ways prone to adsorption of low levels of organic compounds. The need for modification of the inner wall surface of PDMS channels may often be necessary, and in this paper, we describe an easy and effective method using the amine-containing polymer PolyE-323 to deactivate both fused-silica and PDMS surfaces. The adsorption of selected peptides to untreated surfaces was compared to PolyE-323-modified surfaces, using both radionuclide imaging and capillary electrophoresis experiments. The polyamine modification displayed a substantially reduced adsorption of three hydrophobic test peptides compared to the native PDMS surface. Filling and storage of aqueous solution were also possible in PolyE-323-modified PDMS channels. In addition, hybrid microstructures of fused silica and PDMS could simultaneously be deactivated in one simple coating procedure.     

Microstructure, Chemical and Phase Composition of Chromium Silicide Diffusion Coatings on Carbon Steels

The microstructure, chemical and phase composition of chromium silicide diffusion coatings on steels 20, 45, U8, and U10 are studied. It is established that the phases Cr²³C⁶ and Cr⁷C³ with a silicon content in them of up to 0.25 at.% form at the surface of chromium silicide coatings. The maximum silicon content at 7% in steels 20 and 45 is observed beneath the carbide layer at a depth of 40–50 µm, but for steel U10 it is 1.9% at the carbide layer-matrix boundary. It is shown that the corrosion resistance of chromium silicide diffusion coatings increases markedly compared with uncoated specimens: by a factor of 15–30 depending on the acid used (H₂SO₄, HCl, H₃PO₄, HNO₃, CH₃COOH). There is also an increase in the cavitation resistance of articles with chromium silicide coatings in water and 3% NaCl solution.__________Translated from Poroshkovaya Metallurgiya, Nos. 1–2(441), pp. 23–30, January–February, 2005.     

Thermal and electrical properties of nitrile‐containing polyimide/BaTiO3 composite films

Polyimide composite films were prepared by mixing the BaTiO₃ particles into poly(amic acid) solution followed by film casting and thermal imidization under controlled temperature conditions. The poly(amic acid) was synthesized by solution polycondensation reaction of 4,4′‐oxydiphthalic anhydride with 2,6‐bis(4‐aminophenoxy)benzonitrile, using N‐methyl‐2‐pyrrolidone as solvent. The surface of BaTiO₃ particles was modified by treating with an aminosilane coupling agent, 3‐aminopropyltriethoxysilane. Fourier transform infrared spectroscopy, X‐ray diffraction and scanning electron microscopy were used to characterize the structure and properties of the composites. The influence of BaTiO₃ content on the composite film properties was evidenced. The films exhibited good thermal stability having the initial decomposition temperature above 520°C. They had stable dielectric properties over large intervals of temperature and frequency. The dielectric constant and the dielectric loss increased with the increase of BaTiO₃ content. The dynamic mechanical analysis and dielectric spectroscopy revealed subglass transitions γ and β. At higher temperature an α‐relaxation that corresponds to the glass transition and a conductivity process were evidenced. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Cermets surface transformation under erosive and abrasive wear

The subsurface developed in ceramic-metal composites WC-Co, TiC-NiMo and Cr₃C₂-Ni during tribological testing (abrasion, sliding, erosion) under different conditions (impact angle, velocity, pressure, temperature) is the primary concern of the study. Mechanisms responsible for mechanically mixed layer (MML) development and wear resistance of materials are discussed in details. Instrumented indentation combined with consecutive polishing-testing procedure was used for mechanical characterisation. Microstructural features of the worn surface and subsurface region were studied with the help of optical microscope and scanning electron microscope equipped with energy dispersive spectroscopy analyser to evaluate difference between properties of the bulk and modified subsurface layers of materials.Formation of subsurface layer is found to be an essential feature of materials response to applied loading. Modified layer consists of highly deformed binder metal; cracked and decohesed large grains of carbides; embedded and/or fused debris of erosive/abrasive particles; and products of oxidation.     

2-Mercaptobenzothiazolate complexes of rare earth metals and their electroluminescent properties

We have demonstrated the electroluminescent (EL) properties of 2-mercaptobenzothiazolate complexes of rare earth metals [Ln(mbt)₃, Ln = Y, Sm, Eu, Gd, Tb, Dy, Tm] using simple non-doped two-layer organic light emitting diode with the configuration of indium tin oxide/N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine/Ln(mbt)₃/Yb. It was found that 2-mercaptobenzothiazolate complexes have highly efficient intra-energy transfer from the singlet to the triplet state of the ligand, and then to the excited state of the central lanthanide ions. Thus Y(mbt)₃ and Gd(mbt)₃ exhibit the broad ligand-centered emission with maximum near 600 nm and Dy(mbt)₃, Tb(mbt)₃ and Tm(mbt)₃ complexes exhibit pure sharp emission bands from the intra f–f transitions of lanthanide ions Tb³⁺: ⁵D₄ → ⁷F₆ (492 nm), ⁵D₄ → ⁷F₅ (547 nm), ⁵D₄ → ⁷F₄ (589 nm), ⁵D₄ → ⁷F₃ (624 nm); Dy³⁺: ⁴F_9/2 → ⁶H_13/2 (575 nm) and Tm³⁺: ³H₄–³H₆ (795 нм).     

Catalytic Deoxygenation of Stearic Acid and Palmitic Acid in Semibatch Mode

The deoxygenation experiments of different reactants, i.e., pure palmitic acid, stearic acid, and a technical grade stearic acid containing a mixture of 59% of palmitic and 40% of stearic acid were successfully performed over 4 wt% Pd/C mesoporous catalyst at 300 °C under 17 bar of 5% H₂ in argon. The main product in catalytic deoxygenation of saturated fatty acids, C16 and C18, were aliphatic chain length hydrocarbons containing one less carbon than the corresponding acid. Additionally it was found that the deoxygenation rates of different reactant were independent on carbon chain length of its fatty acids.     

Novel Antitumor L‐Arabinose Derivative of Indolocarbazole with High Affinity to DNA

Novel indolocarbazole derivative 12‐(α‐L ‐arabinopyranosyl)indolo[2,3‐α]pyrrolo[3,4‐c]carbazole‐5,7‐dione (AIC) demonstrated high potency (at submicromolar concentrations) against the NCI panel of human tumor cell lines and transplanted tumors in vivo. In search of tentative targets for AIC, we found that the drug formed high affinity intercalative complexes with d(AT)₂₀, d(GC)₂₀ and calf thymus DNA (binding constants (1.6×10⁶) M ^?1≤K_a≤(3.3×10⁶) M ^?1). The drug intercalated preferentially into GC pairs of the duplex. Importantly, the concentrations at which AIC formed the intercalative complexes with DNA (C≤1 μM ) were identical to the concentrations that triggered p53‐dependent gene reporter transactivation, the replication block, the inhibition of topoisomerase I‐mediated DNA relaxation and death of HCT116 human colon carcinoma cells. We conclude that the formation of high affinity intercalative complexes with DNA is an important factor for anticancer efficacy of AIC.     

The Effect of Cucurbit[7]uril on the Antitumor and Immunomodulating Properties of Oxaliplatin and Carboplatin

Cucurbit[7]uril (CB[7]) is a molecular container that may form host–guest complexes with platinum(II) anticancer drugs and modulate their efficacy and safety. In this paper, we report our studies of the effect of CB[7]–oxaliplatin complex and the mixture of CB[7] and carboplatin (1:1) on viability and proliferation of a primary cell culture (peripheral blood mononuclear cells), two tumor cell lines (B16 and K562) and their activity in the animal model of melanoma. At the same time, we studied the impact of platinum (II) drugs with CB[7] on T cells and B cells in vitro. Although the stable CB[7]–carboplatin complex was not formed, the presence of cucurbit[7]uril affected the biological properties of carboplatin. In vivo, CB[7] increased the antitumor effect of carboplatin, but, at the same time, increased its acute toxicity. Compared to free oxaliplatin, its complex with CB[7] shows a greater cytotoxic effect on tumor cell lines B16 and K562, while in vivo, the effects of the free drug and encapsulated drug were comparable. However, in vivo studies also demonstrated that the encapsulation of oxaliplatin in CB[7] lowered the toxicity of the drug.     

Sintering kinetics of ZrO2 nanopowders modified by group IV elements

The sintering behavior of tetragonal zirconia nanopowders modified by the group IV elements at the initial sintering stage was investigated. It was found that different additives SiO₂, SnO₂, and GeO₂ have a significant influence on the densification kinetics of 3Y-TZP nanopowders obtained by coprecipitation during sintering as it depends on the amount of additives (0-5 wt%). The shrinkage of zirconia-based specimens during the nonisothermal sintering was analyzed using the dilatometric data. The constant rate of heating technique was applied in order to determine the dominant mass transfer mechanism at the initial stage of sintering in modified zirconia nanopowders. It was found that there was a change in the mass transfer mechanism and diffusion activation energy in 3Y-TZP as a result of the additives. The dominant sintering mechanism in 3Y-TZP changed from the volume diffusion to the grain boundary diffusion due to the addition of SiO₂ and SnO₂ and the sintering activation energy increased in these cases. However, GeO₂ additive activated the viscous flow mechanism in sintering process of 3Y-TZP nanopowders which led to acceleration of the densification due to the decrease in the diffusion activation energy.