Comparison of titanium-nitride-oxide-coated stents with zotarolimus-eluting stents for coronary revascularization a randomized controlled trial

Objectives This study sought to compare the efficacy of passive stent coating with titanium-nitride-oxide (TiNO) with drug-eluting stents releasing zotarolimus (ZES) (Endeavor, Medtronic, Minneapolis, Minnesota). Background Stent coating with TiNO has been shown to reduce restenosis compared with bare-metal stents in experimental and clinical studies. Methods In an assessor-blind noninferiority study, 302 patients undergoing percutaneous coronary intervention were randomized to treatment with TiNO or ZES. The primary endpoint was in-stent late loss at 6 to 8 months, and analysis was by intention to treat. Results Both groups were well balanced with respect to baseline clinical and angiographic characteristics. The TiNO group failed to reach the pre-specified noninferiority margin for the primary endpoint (in-stent late loss: 0.64 ± 0.61 mm vs. 0.47 ± 0.48 mm, difference: 0.16, upper 1-sided 95% confidence interval [CI]: 0.26; pnoninferiority = 0.54), and subsequent superiority testing was in favor of ZES (psuperiority = 0.02). In-segment binary restenosis was lower with ZES (11.1%) than with TiNO (20.5%; psuperiority = 0.04). A stratified analysis of the primary endpoint found particularly pronounced differences between stents among diabetic versus nondiabetic patients (0.90 ± 0.69 mm vs. 0.39 ± 0.38 mm; pinteraction = 0.04). Clinical outcomes showed a similar rate of death (0.7% vs. 0.7%; p = 1.00), myocardial infarction (5.3% vs. 6.7%; p = 0.60), and major adverse cardiac events (21.1% vs. 18.0%, hazard ratio: 1.19, 95% CI: 0.71 to 2.00; p = 0.50) at 1 year. There were no differences in rates of definite or probable stent thrombosis (0.7% vs. 0%; p = 0.51) at 1 year. Conclusions Compared with TiNO, ZES was superior with regard to late loss and binary restenosis. The concept of passive stent coating with TiNO remains inferior to drug-eluting stent technology in reducing restenosis. ([TIDE] Randomized Trial Comparing Titan Stent With Zotarolimus-Eluting Stent: NCT00492908)

Osteoblast responses to different oxide coatings produced by the sol-gel process on titanium substrates

In order to improve the osseointegration of endosseous implants made from titanium, the structure and composition of the surface were modified. Mirror-polished commercially pure (cp) titanium substrates were coated by the sol-gel process with different oxides: TiO(2), SiO(2), Nb(2)O(5) and SiO(2)-TiO(2). The coatings were physically and biologically characterized. Infrared spectroscopy confirmed the absence of organic residues. Ellipsometry determined the thickness of layers to be approximately 100nm. High resolution scanning electron microscopy (SEM) and atomice force microscopy revealed a nanoporous structure in the TiO(2) and Nb(2)O(5) layers, whereas the SiO(2) and SiO(2)-TiO(2) layers appeared almost smooth. The R(a) values, as determined by white-light interferometry, ranged from 20 to 50nm. The surface energy determined by the sessile-drop contact angle method revealed the highest polar component for SiO(2) (30.7mJm(-2)) and the lowest for cp-Ti and 316L stainless steel (6.7mJm(-2)). Cytocompatibility of the oxide layers was investigated with MC3T3-E1 osteoblasts in vitro (proliferation, vitality, morphology and cytochemical/immunolabelling of actin and vinculin). Higher cell proliferation rates were found in SiO(2)-TiO(2) and TiO(2), and lower in Nb(2)O(5) and SiO(2); whereas the vitality rates increased for cp-Ti and Nb(2)O(5). Cytochemical assays showed that all substrates induced a normal cytoskeleton and well-developed focal adhesion contacts. SEM revealed good cell attachment for all coating layers. In conclusion, the sol-gel-derived oxide layers were thin, pure and nanostructured; consequent different osteoblast responses to those coatings are explained by the mutual action and coadjustment of different interrelated surface parameters.

Five-year results of a randomised comparison of titanium-nitride-oxide-coated stents with zotarolimus-eluting stents for coronary revascularisation.

Aims: Stents with a passive coating of titanium-nitride-oxide (TiNO) have been compared with Endeavor® zotarolimus-eluting stents (E-ZES) with regard to the primary endpoint of in-stent late lumen loss at six to eight months. The objective of the present analysis was to compare the long-term outcomes of TiNO stents with E-ZES up to five years of clinical follow-up. Methods and results: A total of 302 patients had been randomly allocated to treatment with TiNO or E-ZES. Up to five years of follow-up, major adverse cardiac events (MACE), the composite of cardiac death, myocardial infarction, or clinically indicated target vessel revascularisation (TLR), were observed in 27.6% of patients treated with TiNO stents and 25.3% of patients treated with E-ZES (RR 1.13, 95% CI: 0.72-1.75, p=0.60), with the majority of events related to clinically indicated TVR (TiNO 21.7% versus E-ZES 20.7%, RR 1.10, 95% CI: 0.67-1.81). There were no differences with respect to individual events including cardiac death, myocardial infarction or stent thrombosis between the two treatment arms up to five years of follow-up. A majority of patients remained free from angina throughout the entire study duration (TiNO 77.3% versus E-ZES 76.1%, p=0.92). Conclusions: Final five-year outcomes of the TIDE trial comparing TiNO stents with E-ZES revealed increased rates of MACE driven primarily by clinically indicated TVR. The TIDE trial is registered at ClinicalTrials.gov: NCT00492908.

Breakdown voltage of metal-oxide resistors in liquid argon

We characterized a sample of metal-oxide resistors and measured their breakdown voltage in liquid argon by applying high voltage (HV) pulses over a 3 second period. This test mimics the situation in a HV-divider chain when a breakdown occurs and the voltage across resistors rapidly rise from the static value to much higher values. All resistors had higher breakdown voltages in liquid argon than their vendor ratings in air at room temperature. Failure modes range from full destruction to coating damage. In cases where breakdown was not catastrophic, subsequent breakdown voltages were lower in subsequent measuring runs. One resistor type withstands 131 kV pulses, the limit of the test setup.

Adsorption of biomedical coating molecules, amino acids, and short peptides on magnetite (110)

Superparamagnetic iron oxide nanoparticles for biomedical applications are usually coated with organic molecules to form a steric barrier against agglomeration. The stability of these coatings is well established in the synthesis medium but is more difficult to assess in physiological environment. To obtain a first theoretical estimate of their stability in such an environment, we perform density functional theory calculations of the adsorption of water, polyvinyl alcohol (PVA) and polyethylene glycol (PEG) coating molecules, as well as the monomer and dimer of glycine as a prototype short peptide, on the (110) surface of magnetite (Fe3O4) in vacuo. Our results show that PVA binds significantly stronger to the surface than both PEG and glycine, while the difference between the latter two is quite small. Depending on the coverage, the wateradsorption strength is intermediate between PVA and glycine. Due to its strongly interacting OH side groups, PVA is likely to remain bound to the surface in the presence of short peptides. This stability will have to be further assessed by molecular dynamics in the solvated state for which the present work forms the basis.

(Table 1, page 129) Chemical composition of ferromanganese coating on glacial erratics from Lydonia Canyon

Ferromanganese coatings have been found on glacial erratics in Lydonia Canyon, off the United States northeastern coast. The coatings, which are about 17 µm thick, consist of an outer manganese-rich layer which covers the top of the erratic, a middle transitional layer, and an internal iron-rich layer that encircles the entire surface of the erratic. Chemical analyses of the coatings, when compared with similar data on abyssal marine ferromanganese deposits, reveal comparable Mn/Fe ratios, higher P and Ti concentrations, and an order of magnitude less of Co, Ni, Cu, and most other metals. A comparison of the Lydonia Canyon coatings with desert varnishes reveals obvious chemical, mineralogical, and morphological differences.

Total oxidation of naphthalene at low temperatures using palladium nanoparticles supported on inorganic oxide-coated cordierite honeycomb monoliths

A study on the preparation of thin films of ZSM-5 and BETA zeolites, and a SAPO-5 silicoaluminophosphate, supported on cordierite honeycomb monoliths by in situ synthesis was carried out for their use as catalyst supports. Furthermore γ-Al2O3 was also coated onto a cordierite honeycomb monolith by a dip-coating method for use as a standard support. Structured monolithic catalysts were prepared by impregnation of the aforementioned coated monoliths with polymer-protected Pd nanoparticles. The monolithic catalysts have been tested for the total oxidation of naphthalene (100 ppm, GHSV 1220 h−1). From the combined use of the zeolite with polymer-protected nanoparticles, enhanced catalytic properties have been found for the total abatement of naphthalene. The Pd/MBETA and Pd/MZSM-5 catalytic monoliths have shown excellent activity with a high degree of stability, even after undergoing accelerated ageing experiments.

Synthesis and electrochemical properties of mesoporous nickel oxide

Mesoporous Ni(OH)(2) is synthesized using sodium dodecyl sulfate as a template and urea as a hydrolysis-controlling agent. Mesoporous NiO with a centralized pore-size distribution is obtained by calcining Ni(OH)(2) at different temperatures. The BET specific surface area reaches 477.7 m(2) g(-1) for NiO calcined at 250 degreesC. Structure characterizations indicate a good mesoporous structure for the nickel oxide samples. Cyclic voltammetry shows the NiO to have good capacitive behaviour due to its unique mesoporous structure when using a large amount of NiO to fabricate the electrode. Compared with NiO prepared by dip-coating and cathodic precipitation methods, mesoporous NiO with a controlled pore structure can be used in much larger amounts to fabricate electrodes and still maintain a high specific capacitance and good capacitive behaviour. (C) 2004 Elsevier B.V. All rights reserved.

Synthesis and characterization of mesoporous nickel oxide and its application to electrochemical capacitor

Mesoporous Ni(OH)(2) was synthesized using cationic surfactant as template and urea as hydrolysis-controlling agent. Mesoporous NiO with centralized pore size distribution was obtained by calcining Ni(OH)(2) at different temperatures. The BET specific surface area reaches 477.7 m(2).g(-1) for NiO calcined at 523 K. Structure characterizations indicate the polycrystalline pore wall of mesoporous nickel oxide. The pore-formation mechanism is also deduced to be quasi-reverse micelle mechanism. Cyclic voltammetry shows the good capacitive behavior of these NiO samples due to its unique mesoporous structure when using large amount of NiO to fabricate electrode. Compared with NiO prepared by dip-coating and cathodic precipitation methods, this mesoporous NiO with controlled pore structure can be used in much larger amount to fabricate the electrode and still maintains high specific capacitance and good capacitive behavior.

Sol–gel derived coating applied to long-period gratings for enhanced refractive index sensing properties

Long-period fibre gratings (LPGs) have previously been used to detect quantities such as temperature, strain, and refractive index (RI). We report here, to the best of our knowledge, the first investigation on refractive index sensing properties of LPGs with sol–gel derived titanium and silicon oxide coatings. It is revealed that the RI sensitivity of an LPG is affected by both the thickness and the index value of the coating; a coating with higher index and thickness will enhance the LPG RI sensitivity significantly. The surrounding refractive index induced LPG resonance shift has been evaluated over the LPGs' most sensitive RI region from 1.42 to 1.44. We have identified that, in this region, the uncoated LPG has an RI sensitivity of (-673.0 ± 0.4) nm/uri (unit of refractive index) while the LPG coated with titanium oxide exhibits a sensitivity as high as (-1067.15 ± 0.04) nm/uri. The experimental results also reveal that, even in the RI insensitive region around 1.33, there still is a marked enhancement in RI sensitivity of the sol–gel coated LPG compared to the uncoated one. This is potentially significant as coated LPGs may be extended to low RI gas and semi-liquidized based sensing applications.

Surface coating deterioration studies

This project is concerned with the deterioration of surface coatings as a result of weathering and exposure to a pollutant gas (in this case nitric oxide). Poly(vinyl chloride) (PVC) plastisol surface coatings have been exposed to natural and artificial weathering and a comparison of the effects of these two types of weathering has been made by use of various analytical techniques. These techniques have each been assessed as to their value in providing information regarding changes taking place in the coatings during ageing, and include, goniophotometry, micro-penetrometry, surface energy measurements, weight loss measurements, thermal analysis and scanning electron microscopy. The results of each of these studies have then been combined to show the changes undergone by PVC plastisol surface coatings during ageing and to show the effects which additives to the coatings have on their behaviour and in particular the effects of plasticiser, pigment and uv and thermal stabilisers. Finally a preliminary study of the interaction between five commercial polymers and nitric oxide has been carried out, the polymers being polypropylene, cellulose acetate butyrate, polystyrene, polyethylene terephthalate and polycarbonate. Each of the samples was examined using infra-red spectroscopy in the transmission mode.

The stability of pharmaceutical powders: effect of additives and coating

The decomposition of drugs in the solid state has been studied using aspirin and salsalate as models. The feasibility of using suspension systems for predicting the stability of these drugs in the solid state has been investigated.. It has been found that such systems are inappropriate in defining the effect of excipients on 'the decomposition of the active drug due to chqnges in the degradation pathway. Using a high performance liquid chromatographic method, magnesium stearate was shown to induce the formation of potentlally immunogenic products in aspirin powders. These products which included salicylsalicylic acid .and acetylsalicyclsalicylic acid were not detected in aspirin suspensions which had undergone the same extent of decomposition. By studying the effect of pH and of added excipients on the rate of decomposition of aspirin in suspension systems, it has been shown that excipients such as magnesium stearate containing magnesium oxide, most probably enhance the decomposition of both aspirin and salsalate by alkalinising the aqueous phase. In the solid state, pH effects produced by excipients appear to be relatively unimportant. Evidence is presented to suggest that the critical parameter is a depression in melting point induced by: the added excipient. Microscopical examination in fact showed the formation of clear liquid layers in aspirin samples containing added magnesium stearate but not in control samples. Kinetic equations which take into account both the diffusive barrier presented by the liquid films and the. geometry of the aspirin crystals were developed. Fitting of the .experimental data to these equations showed good agreement. with the postulated theory. Monitorjng of weight issues during the decomposition of aspirin revealed that in the solid systems studied where the bulk of the decomposition product sublimes, it is possible to estimate the extent of degradation from the residual weight, provided the initial weight is known. The corollary is that in such open systems, monitoring of decomposition products is inadequate for assessing the extent of decomposition. In addition to the magnesium stearate-aspirin system, mapyramine maleate-aspirin mixtures were used to model interactive systems. Work carried out in an attempt to stabilise such systems included microencapsulation and film coating. The protection obtained was dependent on the interactive species used. Gelatin for example appeared to stabilise aspirin against the adverse effects of magnesium stearate but increased its decomposition in the presence of mapyramine maleate.

A study in the reduction of efficiency of nitrogen oxide removal catalysts for automobiles

Automotive catalysts are the most effective short-term answer to air pollution from automobiles. Since strict control of exhaust emissions is, or will be,covered by legislation in most developed countries in the world, catalytic devices will be increasingly fitted to cars. There is consequently an urgent need for the development of catalysts that will not compete for scarce precious metal resources. A number of problems have already been identified in connection with base metal catalysts but quantitative investigations are lacking. The base metal reduction catalysts developed by Imperial Chemical Industries Limited, catalysts and Chemical Group, in collaboration with the Air Pollution Control Laboratory, B L Cars Limited for automotive emission control, are susceptible to de-activation by three major mechanisms. These are: physical loss of the wash-coat (a high surface area coating which supports the active species), aggregation of the active species and poisoning by fuel and engine oil additives. This thesis is especially concerned with the first two of these and attempts to indicate the relative magnitude .of their effect on the activity of. the catalysts. Aggregation of the active species or sintering, as it is loosely called, was studied by using impregnated granules to overcome effects due to the loss of the wash-coat. Samples were aged in a synthetic exhaust gas, free from poisons, and metal crystallite sizes were measured by scanning-electron microscopy. The increase in particle size was correlated with the loss in catalytic activity. In order to maintain a link with the real conditions of service a number of monolithic catalysts were tested in an engine-dynamometer and several previously tested endurance catalysts were examined. A mechanism is proposed for the break-up and subsequent 10s.5 of the wash-coat and suggestions for improved resistance to loss of the' coating and active species are proposed.

Insights into the influence of solvent polarity on the crystallization of poly(ethylene oxide) spin-coated thin films via in situ grazing incidence wide-angle X-ray scattering

Controlling polymer thin-film morphology and crystallinity is crucial for a wide range of applications, particularly in thin-film organic electronic devices. In this work, the crystallization behavior of a model polymer, poly(ethylene oxide) (PEO), during spin-coating is studied. PEO films were spun-cast from solvents possessing different polarities (chloroform, THF, and methanol) and probed via in situ grazing incidence wide-angle X-ray scattering. The crystallization behavior was found to follow the solvent polarity order (where chloroform < THF < methanol) rather than the solubility order (where THF > chloroform > methanol). When spun-cast from nonpolar chloroform, crystallization largely followed Avrami kinetics, resulting in the formation of morphologies comprising large spherulites. PEO solutions cast from more polar solvents (THF and methanol) do not form well-defined highly crystalline morphologies and are largely amorphous with the presence of small crystalline regions. The difference in morphological development of PEO spun-cast from polar solvents is attributed to clustering phenomena that inhibit polymer crystallization. This work highlights the importance of considering individual components of polymer solubility, rather than simple total solubility, when designing processing routes for the generation of morphologies with optimum crystallinities or morphologies.