Time-resolved cathodoluminescence and photoluminescence of nanoscale oxides

The nanostructured oxide materials such as ZnO, ZrO₂, and Y₃Al₅O₁₂ (YAG) are perspective materials for transparent scintillating and/or laser ceramics. The luminescence properties of single crystals, nanopowders and ceramic were compared. Nominally pure and rare-earth doped nanopowders and ceramics have been studied by means of time-resolved luminescence spectroscopy.The fast blue luminescence band was studied in ZnO ceramics sintering from different raw materials.The luminescence centres of ZrO₂:Y were compared in a single crystal, ceramic and nanopowder.It is shown that ceramic sintering parameters have a strong influence on time-resolved luminescence characteristics in cerium-doped YAG.     

Biodiesel Production using Lewis Catalysts under Ultrasonic Activation

Biodiesel can be produced by transesterification of oil triglycerides, as well as by esterification of fatty acids using feedstock materials rich in free fatty acids)FFAs). Utilization of such feedstocks can gain substantial economical profit and solve a problem of disposal of residual raw materials. To find an effective method of biodiesel production from FFA, we developed esterification of FFAs under ultrasonic activation using Lewis acids as catalysts. Homologous catalyst BF₃ and heterogeneous AlCl₃ were highly effective in reactions of model FFAs methylation under ultrasonic activation, when the reaction yield reached 100 %. Ethylation at the same conditions was less successful.     

Deformation behavior of nanostructured ZnO films on glass

Nanostructured ZnO films on glass substrate were studied by nanoindentation, scanning electron and atomic force microscopy. The films were obtained by a straightforward mechanoactivated oxidation method. The morphology of the obtained films was grained with a grain size in the range 50-100 nm and the thickness was approximately 2 μm. A detailed deformation behavior of ZnO films, critical parameters and indentation induced plastic deformation mechanisms were determined in correlation to bulk ZnO, Si single crystal and commercial ZnO films. In comparison to a single crystal ZnO, nanostructured films exhibit increased hardness (9 GPa); however, the Young's modulus is decreased (120 GPa). A directly detectable evidence of brittleness, “pop-in” and “pile-up” phenomena in ZnO films was not observed. The ZnO/glass interface is stable and exhibits high adhesion, no signs of delamination or presence of brittleness cracks were detected (even at load P_max > 2 N). The role of grain boundaries on the properties of deformation behavior of ZnO nanostructured films has been discussed.     

Analysis of monitoring and multipath support on top of OpenFlow specification

In general, traffic is pushed through a single path despite the existence of alternative paths in networks. For example, routing solutions based on spanning tree prune the topology to prevent loops, consequently preventing also the use of alternative paths. Research on quality of service frequently advocates that the use of alternative paths is interesting for enforcing Service Level Agreements (SLAs), bypassing bottlenecks created by shortest paths. In this paper, we are interested in analyzing the support for monitoring network traffic and for provisioning of multipaths in software‐defined networking (SDN), given the strong platform it provides for experimentation of new networked solutions. Our approach firstly enriches the topology view at the control plane with data gathered through fine grain data plane monitoring. On the basis of such enriched view, our system determines the path, or multipaths, necessary to enforce the specified SLA. We propose 2 extension modules to an OpenFlow controller: SDNMon, which monitors the data plane to enrich the topology information at the control plane, and MP‐Routing, which determines a set of paths, in the absence of a single path capable of enforcing the SLA. Both modules are extensively evaluated, and the results not only demonstrate what can be achieved in terms of accuracy in SDNMon and in terms of quality of service benefits in MP‐Routing but also highlight some limitations of OpenFlow specification. On the basis of our findings, we propose a set of new counters to Per Port and Per Flow granularity levels of OpenFlow specification.     

Multiplex analysis of cytokines as biomarkers that differentiate benign and malignant thyroid diseases

Thyroid cancer incidence is increasing, and its diagnosis can be challenging. Fine needle biopsy, the principal clinical tool to make a tissue diagnosis, leads to inconclusive diagnoses in up to 30% of the cases, leading to surgery. Advances in proteomics are improving abilities to diagnose malignant conditions using small samples of tissue or body fluids. We hypothesized that analysis of serum growth factors would uncover diagnostically informative differences between benign and malignant thyroid conditions. Using xMAP profiling, we evaluated concentrations of 19 cytokines, chemokines, and growth factors. We used sera from 23 patients with cancer (Malignant group), 24 patients with benign nodular thyroid disease (Benign group), and 23 healthy subjects (Normal group). In univariate analysis, five factors (epithelial growth factor, hepatocyte growth factor, Interleukins‐5 and ‐8, and regulated upon activation, normally T‐expressed and presumably secreted (RANTES) distinguished subjects with thyroid disease from the Normal group. In multivariate analysis, the set {Interleukin‐8, hepatocyte growth factor, monocyte‐induced γ interferon, interleukin‐12 p40} achieved noteworthy discrimination between Benign and Malignant groups (area under the receiver operating characteristics curve was 0.81 (95% confidence interval: 0.65–0.90)). Multiplex panels of serum biomarkers may be promising tools to diagnose cancer in patients presenting with evidence of nodular thyroid disease.     

Different Aspects of Using Ultrasound to Combat Microorganisms

Growing resistance of microorganisms to antibiotics due to their widespread use has led to multiple bacterial infections posing a serious threat to health and human life. Low-frequency ultrasound is one of physical methods for inactivation of pathogenic microbial cells. Application of ultrasound is safe, demonstrates good tissue penetration without significant attenuation of energy, and does not induce microbial resistance. Bactericidal effect of ultrasound is based on acoustic cavitation—the growth and collapse of microbubbles in a liquid medium, resulting in shock waves, shear forces, and microjets which cause irreversible damage and inactivation of microorganisms. The present review combines and analyzes literature data on in vitro and in vivo studies and summarizes works demonstrating the ability of ultrasound, alone or in combination with other methods, to combat pathogenic microorganisms. The results of various studies presented in this review show that low-frequency ultrasound has a noticeable antimicrobial effect on planktonic cells of microorganisms and biofilms. Ultrasound synergistically enhances the effectiveness of other antibacterial agents and activates molecules called sonosensitizers, resulting in the formation of compounds toxic to microbial cells. Ultrasound can also promote local release of antimicrobial drugs from liposomes, as well as from medical implants.     

Organic sorbate-organoclay interactions in aqueous and hydrophobic environments: sorbate-water competition

Sorption of nitrobenzene, phenol, and m-nitrophenol from water and n-hexadecane was measured on Na-montmorillonite and organoclays in which 41 and 90% of the exchange capacity of the Na-clay was occupied by hexadecyltrimethylammonium. The strength of sorbate-sorbent interactions in n-hexadecane for all three sorbents was in the following order: nitrobenzene < phenol < m-nitrophenol. The magnitude of the distribution coefficients suggests that the contribution to solute uptake of partitioning between n-hexadecane and the organic pseudophase of the dried organoclays is minor, whereas the major contribution is from adsorptive sorbate-sorbent interactions. Sorption isotherms obtained in different solvents were compared using a sorbate activity scale. In the organoclays, the stronger the tendency of a sorbate to interact with sorption sites, the less pronounced is the reduction in the activity-based sorption due to competition with water. The order of this reduction for the different sorbates is nitrobenzene > phenol > m-nitrophenol. The weakening of sorbate-sorbent interactions resulting from water-sorbate competition might be mitigated by interaction between the organic sorbate and sorbed water molecules. Since the more strongly interacting organic compounds are less susceptible to suppression of sorption in the presence of water, hydrating organoclays may result in an increased differentiation between "weakly" and "strongly" interacting ("nonpolar" and "polar") compounds in the organoclay phase.     

Antibacterial Activity of Rose Bengal Entrapped in Organically Modified Silica Matrices

Photosensitizers (PSs) are known as powerful antibacterial agents that are activated by direct exposure to visible light. PSs can be noncovalently entrapped into the silica gel network for their controlled release into a contaminated area. The immobilization of PS-containing gel matrices on a polymer support expands their possible applications, such as antibacterial surfaces and coatings, which can be used for the disinfection of liquids. In the current study, we report the use of Rose Bengal (RB) incorporated into organically modified silica matrices (RB@ORMOSIL matrices) by the sol-gel technique. The RB matrices exhibit high activity against Gram-positive and Gram-negative bacteria under illumination by white light. The amount and timing of solidifier addition to the matrix affected the interaction of the latter with the RB, which in turn could affect the antibacterial activity of RB. The most active specimen against both Gram-positive and Gram-negative bacterial cells was the RB6@ORMOSIL matrix immobilized on a linear low-density polyethylene surface, which was prepared by an easy, cost-effective, and simple thermal adhesion method. This specimen, RB6@OR@LLDPE, showed the low release of RB in an aqueous environment, and exhibited high long-term antibacterial activity in at least 14 rounds of recycled use against S. aureus and in 11 rounds against E. coli.     

Dioxo- and aminooxopyrimidotetrathiafulvalenes: π-electron donors for design of conducting materials containing intramolecular hydrogen bonds of nucleic acid base pair type

Dimethyl[2,4-dioxo(1 H,3 H)pyrimido]tetrathiafulvalene (1) and dimethyl-[2-amino-4-oxo(3 H)pyrimido]tetrathiafulvalene (4) form unusual inner salts by oxidation in the presence of bases. The insoluble black-green betaines 2 and 5 react with acids to form cation radical salts. Betaine 2 in the presence of acid and bis-(ethylenedithio)tetrathiafulvalene forms the unexpected double salt 8. In order to synthesise the cation radical salts of 1 and 4, it is necessary to use the ultrasonic method owing to the insolubility of the starting compounds. Electrical measurements of the betaines and cation radical salts in pressed samples show an unexpectedly low resistivity with semiconducting character: for betaine 2 ρ(RT) = 840 O cm, for betaine 5 ρ(RT) = 10 O cm, for salt 7 ρ(RT) = 40 O cm, but for double salt 8 ρ(RT) = 50 O cm. In the case of salt 8, very low values of activation energy of electrical conductivity of the order of kT were observed. The synthesis and purification of tetrathiafulvalene 4 from 5-amino-7-oxo(6 H)-1,3-dithiolo[4,5-d]pyrimidineselone-2 are described. © 1997 John Wiley & Sons, Ltd.     

Dioxo- and aminooxopyrimidotetrathiafulvalenes: π-Electron donors for design of conducting materials containing intramolecular hydrogen bonds of nucleic acid base pair type

Dimethyl[2,4-dioxo(1 H,3 H)pyrimido]tetrathiafulvalene (1) and dimethyl-[2-amino-4-oxo(3 H)pyrimido]tetrathiafulvalene (4) form unusual inner salts by oxidation in the presence of bases. The insoluble black-green betaines 2 and 5 react with acids to form cation radical salts. Betaine 2 in the presence of acid and bis-(ethylenedithio)tetrathiafulvalene forms the unexpected double salt 8. In order to synthesise the cation radical salts of 1 and 4, it is necessary to use the ultrasonic method owing to the insolubility of the starting compounds. Electrical measurements of the betaines and cation radical salts in pressed samples show an unexpectedly low resistivity with semiconducting character: for betaine 2 ρ(RT) = 840 Ω cm, for betaine 5 ρ(RT) = 10 Ω cm, for salt 7 ρ(RT) = 40 Ω cm, but for double salt 8 ρ(RT) = 50 Ω cm. In the case of salt 8, very low values of activation energy of electrical conductivity of the order of kT were observed. The synthesis and purification of tetrathiafulvalene 4 from 5-amino-7-oxo(6 H)-1,3-dithiolo[4,5-d]pyrimidineselone-2 are described. © 1997 John Wiley & Sons, Ltd.