Science.gov

Sample records for adherent alumina scales

  1. The mechanical reliability of alumina scales and coatings

    SciTech Connect

    Alexander, K.B.; Pruebner, K.; Tortorelli, P.F.

    1996-08-01

    The mechanical integrity of oxide scales ultimately determines their ability to protect materials from corrosion and other environmental effects arising from deleterious reactions with gases and condensable products. The microstructure and mechanical behavior of alumina products thermally grown or deposited on Fe-28 at.% Al intermetallic alloys are being characterized in order to develop the knowledge and means to control the mechanical reliability of alumina scales by microstructural manipulation through design and processing. Mechanical characterization involved gravimetric data from cyclic oxidation experiments, in-situ observation of oxidized specimens undergoing flexural loading in a scanning electron microscope, and measurements of hardness, elastic modulus and cracking resistance by nanoindentation. Values of cracking thresholds for Al{sub 2}O{sub 3} scales were consistent with other measurements for surface and bulk alumina. The oxidation behavior of Fe{sub 3}Al alloys coated with a thin (0.5 - 1 {mu}m) alumina film deposited by plasma synthesis has been studied. During exposure in the oxidizing environment, new oxide was formed between the coating and the substrate. The presence of the deposited amorphous oxide inhibited the subsequent thermal oxidation of the metal. Because the thermally grown alumina forms under the deposit, the adherence of the coating is controlled by the strength of the metal/oxide interface that develops during oxidation.

  2. Ionic Segregation on Grain Boundaries in Thermally Grown Alumina Scales

    SciTech Connect

    Pint, Bruce A; Unocic, Kinga A

    2012-01-01

    This study first examined segregation behaviour in the alumina scale formed after 100 h at 1100 C on bare and MCrAlYHfSi-coated single-crystal superalloys with {approx}10 ppma La and Y. For the bare superalloy, Hf and Ti were detected on the grain boundaries of the inner columnar alumina layer. Increasing the oxidation temperature to 1200 C for 2 h did not change the segregation behavior. With the bond coating, both Y and Hf were segregated to the grain boundaries as expected. However, there was evidence of Ti-rich oxide particles near the gas interface suggesting that Ti diffused from the superalloy through the coating. To further understand these segregation observations with multiple dopants, other alumina-forming systems were examined. Alumina scale grain boundary co-segregation of Ti with Y is common for FeCrAl alloys. Co-segregation of Hf and Ti was observed in the scale formed on co-doped NiAl. No La segregation was detected in the scale formed on NiCrAl with only a 19 ppma La addition, however, the scale was adherent.

  3. Depositing Adherent Ag Films On Ti Films On Alumina

    NASA Technical Reports Server (NTRS)

    Honecy, Frank S.

    1995-01-01

    Report discusses cleaning of ceramic (principally, alumina) substrates in preparation for sputter deposition of titanium intermediate films on substrates followed by sputter deposition of outer silver films. Principal intended application, substrates sliding parts in advanced high-temperature heat engines, and outer silver films serve as solid lubricants: lubricating properties described in "Solid Lubricant for Alumina" (LEW-15495).

  4. Moisture-Induced Alumina Scale Spallation: The Hydrogen Factor

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2009-01-01

    For some time our community has been concerned with interfacial spallation of protective alumina scales, not just upon immediate cooldown, but as a time-delayed phenomenon. Moisture-induced delayed spallation (MIDS) and desktop spallation (DTS) of TBC's refer to this process. It is most apparent for relatively adherent alumina scales that have survived cool down in a dry environment, built up considerable thickness and strain energy, and have been somewhat damaged, such as by cyclic oxidation cracking. Indeed, a "sweet zone" can be defined that maximizes the observed effect as a function of all the relevant factors. Moisture has been postulated to serve as a source of interfacial hydrogen embrittlement derived from reaction with aluminum in the alloy at an exposed interface. The purpose of this monograph is to trace the close analogy of this phenomenon to other hydrogen effects, such as embrittlement of aluminides and blistering of alloys and anodic alumina films. A formalized, top-down, logic tree structure is presented as a guide to this discussion. A theoretical basis for interfacial weakening by hydrogen is first cited, as are demonstrations of hydrogen as a reaction product or detected interfacial species. Further support is provided by critical experiments that produce the same moisture effect, but by isolating hydrogen from other potential causative factors. These experiments include tests in H2-containing atmospheres or cathodic hydrogen charging.

  5. Moisture-Induced Alumina Scale Spallation: The Hydrogen Factor

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2010-01-01

    For some time the oxidation community has been concerned with interfacial spallation of protective alumina scales, not just upon immediate cool down, but as a time-delayed phenomenon. Moisture-induced delayed spallation (MIDS) and desktop spallation (DTS) of thermal barrier coatings (TBCs) refer to this process. It is most apparent for relatively adherent alumina scales that have survived initial cool down in a dry environment, have built up considerable thickness and strain energy, and have been somewhat damaged, such as by cyclic oxidation cracking. Indeed, a "sensitive zone" can be described that maximizes the observed effect as a function of all the relevant factors. Moisture has been postulated to serve as a source of interfacial hydrogen embrittlement. Hydrogen is derived from reaction with aluminum in the alloy at an exposed interface. The purpose of this monograph is to trace the close analogy of this phenomenon to other hydrogen-induced effects, such as embrittlement of aluminides and blistering of alloys and anodic alumina films. A formalized, top-down, logic-tree structure is presented as a guide to this discussion. A theoretical basis for interfacial weakening by hydrogen is first cited, as are demonstrations of hydrogen detection as a reaction product or interfacial species. Further support is provided by critical experiments that recreate the moisture effect, but by isolating hydrogen from other potential causative factors. These experiments include tests in H 2-containing atmospheres or cathodic hydrogen charging. Accordingly, they strongly indicate that interfacial hydrogen, derived from moisture, is the key chemical species accounting for delayed alumina scale spallation.

  6. Sulfur and Moisture Effects on Alumina Scale and TBC Spallation

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2007-01-01

    cause is related to a hydrogen embrittlement reaction: Al alloy + 3 H2O = Al(OH)3 + 3H(+) + 3e(-). This mechanism is derived from an analogous moisture-induced hydrogen embrittlement mechanism originally shown for Ni3Al and FeAl intermetallics. Consequently, a cathodic hydrogen charging technique was used to demonstrate that electrolytic de-scaling occurs for these otherwise adherent alumina scales formed on Y-doped Rene'N5, in support of hydrogen effects. Finally, some TBC observations are discussed in light of all of the above. Plasma sprayed 8YSZ coatings, produced on PWA1484 without a bond coat, were found to survive more than 1000 1-hr cycles at 1100 C when desulfurized to below 0.1 ppmw. At higher sulfur (1.2 ppmw) levels, moisture sensitivity and delayed TBC failure, referred to as Desk Top Spallation, occurred at just 200 hr. Despite a large degree of scatter, a factor of 5 in life improvement is indicated for desulfurized samples in cyclic furnace tests, confirming the beneficial effect of low sulfur alloys on model TBC systems. (DTS and moisture effects are also observed on commercially applied PVD 7YSZ coatings on Rene'N5+Y with Pt-aluminide bond coats). These types of catastrophic failure were subverted on the model system by segmenting the substrate into a network of 0.010 high ribs, spaced in. apart, prior to plasma spraying. No failures occurred after 1000 cycles at 1150 C or after 2000 cycles at 1100 C, even after water immersion. The benefit is described in terms of elasticity models and a critical buckling stress.

  7. Dopant effect of yttrium and the growth and adherence of alumina on nickel-aluminum alloys

    NASA Technical Reports Server (NTRS)

    Anderson, A. B.; Mehandru, S. P.; Smialek, J. L.

    1985-01-01

    The atom superposition and electron delocalization molecular orbital theory and large cluster models have been employed to study cation vacancy diffusion in alpha-Al2O3 and the bonding of alpha-Al2O3 to nickel, aluminum, and yttrium surfaces. Al(3+) diffusion barriers in alpha-Al2O3 by the vacancy mechanism are in reasonable agreement with experiment. The barrier to Y(3+) diffusion is predicted to be much higher. Since addition of yttrium to transition metal alloys is known to reduce the growth rate and stress convolutions in protective alumina scales, this result suggests the rate-limiting step in scale growth is cation vacancy diffusion. This may partially explain the beneficial effect of yttrium dopants on scale adhesion. The theory also predicts a very strong bonding between alumina and yttrium at the surface of the alloy. This may also be important to the adhesion phenomenon. It is also found that aluminum and yttrium atoms bond very strongly to nickel because of charge transfer from their higher lying valence orbitals to the lower lying nickel s-d band.

  8. Atomic scale insights on chlorinated gamma-alumina surfaces.

    PubMed

    Digne, Mathieu; Raybaud, Pascal; Sautet, Philippe; Guillaume, Denis; Toulhoat, Hervé

    2008-08-20

    The thermochemistry of chlorinated gamma-alumina surfaces is explored by means of density functional calculations as a function of relevant reaction conditions used in experiments and in high-octane fuel production in the refining industry such as hydrocarbon isomerization and reforming. The role of chlorine as a dope of the Brønsted acidity of gamma-alumina surfaces is investigated at an atomic scale. Combining infrared spectroscopy and density functional theory calculations, the most favorable location of chlorine atoms on the (110), (100) and (111) surfaces of gamma-alumina is found to result either from direct adsorption or from the exchange of basic hydroxyl groups. Moreover, the modification of the hydrogen bond network upon chlorine adsorption is put forward as a key parameter for changing the Brønsted acidity. In a second step, we use a thermodynamic approach based on DFT total energy calculations corrected by the chemical potentials of HCl and H2O to determine the adsorption isotherms of chlorine and the relative surface concentration of hydroxyl groups and chlorine species on the gamma-alumina surfaces. The determination of chlorine content as a function of temperature and partial pressures of H2O and HCl offers new quantitative data required for optimizing the state of the support surface in industrial conditions. The mechanisms of chlorination are also discussed as a function of reaction conditions. PMID:18646849

  9. Formation of highly adherent nano-porous alumina on Ti-based substrates: a novel bone implant coating.

    PubMed

    Briggs, E P; Walpole, A R; Wilshaw, P R; Karlsson, M; Pålsgård, E

    2004-09-01

    Thin, nano-porous, highly adherent layers of anodised aluminium formed on the surface of titanium alloys are being developed as coatings for metallic surgical implants. The layers are formed by anodisation of a 1-5 microm thick layer of aluminium which has been deposited on substrate material by electron beam evaporation. The surface ceramic layer so produced is alumina with 6-8 wt % phosphate ions and contains approximately 5 x 10(8) cm(-2) pores with a approximately 160 nm average diameter, running perpendicular to the surface. Mechanical testing showed the coatings' shear and tensile strength to be at least 20 and 10 MPa, respectively. Initial cell/material studies show promising cellular response to the nano-porous alumina. A normal osteoblastic growth pattern with cell number increasing from day 1 to 21 was shown, with slightly higher proliferative activity on the nano-porous alumina compared to the Thermanox control. Scanning electron microscopy (SEM) examination of the cells on the porous alumina membrane showed normal osteoblast morphology. Flattened cells with filopodia attaching to the pores and good coverage were also observed. In addition, the pore structure produced in these ceramic coatings is expected to be suitable for loading with bioactive material to enhance further their biological properties. PMID:15448410

  10. Conduction in alumina with atomic scale copper filaments

    SciTech Connect

    Xu, Xu; Liu, Jie; Anantram, M. P.

    2014-10-28

    The conductance of atomic scale filaments with three and seven Cu atoms in α-alumina are calculated using ab initio density functional theory. We find that the filament with 3 Cu atoms is sufficient to increase the conductance of 1.3 nm thick alumina film by more than 10{sup 3} times in linear response. As the applied voltage increases, the current quickly saturates and differential resistance becomes negative. Compared to the filament with three Cu atoms, while the conductance of the filament with seven Cu atoms is comparable in linear response, they carry as much as twenty times larger current at large biases. The electron transport is analyzed based on local density of states, and the negative differential resistance in the seven Cu filaments occurs due to their narrow bandwidth.

  11. Strain measurements in thermally grown alumina scales using ruby fluorescence

    SciTech Connect

    Veal, B.W.; Natesan, K.; Koshelev, I.; Grimsditch, M.; Renusch, D. Hou, P.Y.

    1996-12-31

    We have measured strains in alumina scales thermally grown on Fe-Cr- Al alloys by exploiting the strain dependence of the ruby luminescence line. Measurements were done on Fe-5Cr-28Al and Fe-18Cr-10Al (at.%, bal. Fe) oxidized between 300-1300 C with periodic cycling to room temperature. Significantly different levels of strain buildup were observed in scales on these alloys. Results on similar alloys containing a dilute reactive element (Zr or Hf) are also presented. We observe that scales on alloys containing a reactive element (RE) can support higher strains than scales on RE-free alloys. With the luminescence technique, strain relief associated with spallation thresholds is readily observed. In early stage oxidation, the evolution of transition phases is monitored using Raman and fluorescence spectroscopies. The fluorescence technique also provides a sensitive probe of early stage formation of {alpha}-Al{sub 2}O{sub 3}. It appears that, in presence of Cr{sub 2}O{sub 3} or Fe{sub 2}O{sub 3}, the {alpha}-alumina phase can form at anomalously low temperatures.

  12. Stress determination in thermally grown alumina scales using ruby luminescence

    SciTech Connect

    Renusch, D.; Veal, B.W.; Koshelev, I.; Natesan, K.; Grimsditch; Hou, P.Y.

    1996-06-01

    By exploiting the strain dependence of the ruby luminescence line, we have measured the strain in alumina scales thermally grown on Fe-Cr- Al alloys. Results are compared and found to be reasonably consistent with strains determined using x rays. Oxidation studies were carried out on alloys Fe - 5Cr - 28Al and Fe - 18Cr - 10Al (at.%). Significantly different levels of strain buildup were observed in scales on these alloys. Results on similar alloys containing a ``reactive element`` (Zr or Hf) in dilute quantity are also presented. Scales on alloys containing a reactive element (RE) can support significantly higher strains than scales on RE-free alloys. With the luminescence technique, strain relief associated with spallation thresholds is readily observed.

  13. Delayed Alumina Scale Spallation on Rene'n5+y: Moisture Effects and Acoustic Emission

    NASA Technical Reports Server (NTRS)

    Smialek, James L.; Morscher, Gregory N.

    2001-01-01

    The single crystal superalloy Rene'N5 (with or without Y-doping and hydrogen annealing) was cyclically oxidized at 1150 C for 1000 hours. After considerable scale growth (>= 500 hours), even the adherent alumina scales formed on Y-doped samples exhibited delayed interfacial spallation during subsequent water immersion tests, performed up to one year after oxidation. Spallation was characterized by weight loss, the amount of spalled area, and acoustic emission response. Hydrogen annealing (prior to oxidation) reduced spallation both before and after immersion, but without measurably reducing the bulk sulfur content of the Y-doped alloys. The duration and frequency of sequential, co-located acoustic emission events implied an interfacial crack growth rate at least 10(exp -3) m/s, but possibly higher than 10(exp 2) m/s. This is much greater than classic moisture-assisted slow crack growth rates in bulk alumina (10(exp -6) to 10(exp -3) m/s), which may still have occurred undetected by acoustic emission. An alternative failure sequence is proposed: an incubation process for preferential moisture ingress leads to a local decrease in interfacial toughness, thus allowing fast fracture driven by stored strain energy.

  14. Chemical and microstructural characterization of thermally grown alumina scales

    SciTech Connect

    Natesan, K.; Richier, C.; Veal, B.W.

    1995-09-01

    An experimental program has been initiated to evaluate the chemical, microstructural, and mechanical integrity of thermally grown oxide scales to establish requirements for improved corrosion performance in terms of composition, structure, and properties. Iron aluminides of several compositions were selected for the study. Oxidation studies were conducted in air and oxygen environments at 1000{degrees}C. The results showed that the scaling kinetics followed a parabolic rate law but that the rates in early stages of oxidation were significantly greater than in later stages; the difference could be attributed to the presence of fast-growing transient iron oxides in the layer during the early stages. Further, scale failure occurred via gross spallation, scale cracking, and nodule formation and was influenced by alloy composition. Auger electron spectroscopy of Ar-exposed specimens of ternary Fe-Cr-Al alloy showed sulfur on the gas/scale side of the interface; the sulfur decreased as the exposure time increased. Raman spectroscopy and ruby fluorescence were used to examine the scale development as a function of oxidation temperature. Ruby-line shift is used to examine phase transformations in alumina and to calculate compressive strains in thermally grown scales.

  15. A fine-scale nanostructure in γ-alumina

    NASA Astrophysics Data System (ADS)

    Paglia, Gianluca; Bozin, Emil; Billinge, Simon

    2006-03-01

    Despite the preeminent industrial importance of γ-alumina in catalysis, details of the structure remain unresolved due to its 15-30˜nm domain nanocrystalline nature. Diffraction patterns are broad and single crystals are not available making accurate structural solution difficult using conventional crystallographic methods. We have applied a local structural technique, the atomic pair distribution function (PDF) analysis of powder diffraction, to obtain a quantitative structure. This is a total scattering technique that incorporates both Bragg and diffuse scattering information in the PDF, allowing all diffracted intensities from the XRD pattern to be equally considered. Surprisingly, we find a previously unknown fine-scale nanostructure with a domain size ˜ 1 nm. Within these nanodomains the oxygen sublattice is modified from the average structure and retains aspects of the boehmite precursor. This results in a novel and unexpected view of the γ-alumina structure since earlier controversies about it centered on the arrangement of Al ions among different cation sites, whereas the oxygen sublattice arrangement was not usually questioned.

  16. Corrosion performance of alumina scales in coal gasification environments

    SciTech Connect

    Natesan, K.

    1997-02-01

    Corrosion of metallic structural materials in complex gas environments of coal gasification is a potential problem. The corrosion process is dictated by concentrations of two key constituents: sulfur as H{sub 2}S and Cl as HCl. This paper examines the corrosion performance of alumina scales that are thermally grown on Fe-base alloys during exposure to O/S mixed-gas environments. The results are compared with the performance of chromia-forming alloys in similar environments. The paper also discusses the available information on corrosion performance of alloys whose surfaces were enriched with Al by the pack-diffusion process, by the electrospark deposition process, or by weld overlay techniques.

  17. Lightweight alumina refractory aggregate. Phase 2, Pilot scale development

    SciTech Connect

    Swansiger, T.G.; Pearson, A.

    1994-11-01

    Kilogram quantities of refractory aggregate were prepared from both a paste and a pelletized form of extruder feed material in both bench and pilot-scale equipment. The 99{sup +} % alumina aggregate exhibited a bulk density approaching 2.5 g/cm{sup 3} and a fired strength slightly lower than fused alumina. Based on initial evaluation by two refractory manufacturers in brick or castable applications, the new aggregate offered adequate strength with thermal conductivity reductions up to 34%, depending on the temperature and application of the new aggregate in these initial trials. The new aggregate was simply substituted for Tabular{trademark} in the refractory formulation. Thus, there is room for improvement through formulation optimization with the lightweight aggregate. The new aggregate offers a unique combination of density, strength, and thermal properties not available in current aggregate. To this point in time, technical development has led to a pelletized formulation with borderline physical form leaving the Eirich mixer. The formulation requires further development to provide more latitude for the production of pelletized material without forming paste, while still reducing the bulk density slightly to reach the 2.5 g/cm{sup 3} target. The preferred, pelletized process flowsheet was outlined and a preliminary economic feasibility study performed based on a process retrofit into Alcoa`s Arkansas tabular production facilities. Based on an assumed market demand of 20,000 mt/year and an assumed selling price of $0.65/lb (25% more than the current selling price of Tabular{trademark}, on a volume basis), economics were favorable. Decision on whether to proceed into Phase 3 (full- scale demonstration) will be based on a formal market survey in 1994 October.

  18. Sulfur Impurities and the Microstructure of Alumina Scales

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    1997-01-01

    The relationship between the microstructure of alumina scales, adhesion, and sulfur content was examined through a series of nickel alloys oxidized in 1100 to 1200 deg. C cyclic or isothermal exposures in air. In cyclic tests of undoped NiCrAl, adhesion was produced when the sulfur content was reduced, without any change in scale microstructure. Although interfacial voids were not observed in cyclic tests of NiCrAl, they were promoted by long-term isothermal exposures, by sulfur doping, and in most exposures of NiAl. Two single crystal superalloys, PWA 1480 and Rene' N5, were also tested, either in the as-received condition or after the sulfur content had been reduced to less than 1 ppmw by hydrogen annealing. The unannealed alloys always exhibited spalling to bare metal, but interfacial voids were not observed consistently. Desulfurized PWA 1480 and Rene' N5 exhibited remarkable adhesion and no voidage for either isothermal or cyclic exposures. The most consistent microstructural feature was that, for the cases where voids did form, the scale undersides exhibited corresponding areas with ridged oxide grain boundaries. Voids were not required for spallation nor were other microstructural features essential for adhesion. These observations are consistent with the model whereby scale spallation is controlled primarily by interfacial sulfur segregation and the consequent degradation of oxide-metal bonding.

  19. The mechanical reliability of alumina scales and coatings

    SciTech Connect

    Alexander, K.B.; Pruebner, K.; Tortorelli, P.F.

    1996-06-01

    In many high-temperature fossil energy systems, corrosion and deleterious reactions with gases and condensable products in the operating environment often compromise materials performance. The presence of a stable surface oxide (either as thermally-grown scales or deposited coatings) can effectively protect the materials from these reactions if the oxides are slow-growing, dense and adherent to the substrate. The protection these brittle oxide films provide has long been a critical issue, particularly for applications involving severe high-temperature thermal cycles or very aggressive (for example, sulfidizing) environments. The various factors which control the scale/coating integrity and adherence are not well understood. The present multilaboratory collaborative work is intended to define the relationships between substrate characteristics (composition, microstructure, and mechanical behavior) and the structure and protective properties of deposited oxide coatings and/or thermally grown scales. Through such studies, the ultimate goal is to assure environmental protection through effective processing and materials selection leading to the development of corrosion-resistant, high-temperature materials for improved energy and environmental control systems.

  20. A large-scale validation study of the Medication Adherence Rating Scale (MARS).

    PubMed

    Fialko, Laura; Garety, Philippa A; Kuipers, Elizabeth; Dunn, Graham; Bebbington, Paul E; Fowler, David; Freeman, Daniel

    2008-03-01

    Adherence to medication is an important predictor of illness course and outcome in psychosis. The Medication Adherence Rating Scale (MARS) is a ten-item self-report measure of medication adherence in psychosis [Thompson, K., Kulkarni, J., Sergejew, A.A., 2000. Reliability and validity of a new Medication Adherence Rating Scale (MARS) for the psychoses. Schizophrenia Research. 42. 241-247]. Although initial results suggested that the scale has good reliability and validity, the development sample was small. The current study aimed to establish the psychometric properties of the MARS in a sample over four times larger. The scale was administered to 277 individuals with psychosis, along with measures of insight and psychopathology. Medication adherence was independently rated by each individual's keyworker. Results showed the internal consistency of the MARS to be lower than in the original sample, though adequate. MARS total score correlated weakly with keyworker-rated adherence, hence concurrent validity of the scale appeared only moderate to weak. The three factor structure of the MARS was replicated. Examination of the factor scores suggested that the factor 1 total score, which corresponds to the Medication Adherence Questionnaire [Morisky,D.E., Green,L.W. and Levine,D.M., 1986. Concurrent and predictive validity of a self-reported measure of medication adherence. Medical Care. 24, 67-74] may be a preferable measure of medication adherence behaviour to the total scale score. PMID:18083007

  1. Diffusivity in Alumina Scales Grown on Al-MAX Phases

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2014-01-01

    Ti3AlC2, Ti2AlC, and Cr2AlC are oxidation resistant MAX phase compounds distinguished by the formation of protective Al2O3 scales with well controlled kinetics. A modified Wagner treatment was used to obtain interfacial grain boundary diffusivity, deltaD(sub gb,O,int.), from scale growth rates and corresponding grain size. It is based on the p(O2)(exp -1/6) dependency of the double charged oxygen vacancy and oxygen diffusivity, coupled with the effective diffusion constant for short circuit grain boundary paths. Data from the literature for MAX phases was analyzed accordingly, and deltaD(sub gb,O,int.) was found to nearly coincide with the Arrhenius line developed for Zr-doped FeCrAl, where: deltaD(sub gb,O,int.) = 1.8x10(exp -10) exp(-375 kJ/RT) cubic meters/s. Furthermore, this oxidation relation suggests the more general format applicable to bulk samples under ambient conditions: deltaD(sub gb,O) = 7.567x10(exp -8) exp(-544 kJ/RT) p(O2)(exp -1/6) cubic meters/[s x Pa(exp -1/6)]. Data from many other FeCrAl(X) studies were similarly assessed to show general agreement with the relation for deltaD(sub gb,O,int.). This analysis reinforces the view that protective alumina scales grow by similar mechanisms for these Al-MAX phases and oxidation resistant FeCrAl alloys.

  2. Lightweight alumina refractory aggregate: Phase 3, Full-scale demonstration

    SciTech Connect

    Swansiger, T.G.; Pearson, A.

    1996-07-16

    Technical problems (higher than target fired density, and poor intermediate strength after burnout but before sintering) were addressed and solved; solution involved use of large loading of CP-5 alumina (controlled pore, rehydratable), increased loading of one of the binders, and a steam aging step. Resistance of the lightweight aggregate in a brick formulation to steel slag penetration was assessed in a preliminary test and found to be almost as good as that of T-64. Pelletized process economic feasibility study was updated, based on production levels of 10,000 and 20,000 mt/year, the most up- to-date raw material costs, and the assumption of a retrofit into the Arkansas plant tabular production facility. For the 10,000 mt/y production level, the required selling price of 35% more than the T- 64 selling price exceeds the {le}25% objective. The market survey will determine whether to proceed with the full scale demonstration that will produce at least 54.4 mt (120,000 lb) of the aggregate for incorporation into products, followed by end-user testing and evaluation.

  3. Microstructural and mechanical characterization of alumina scales thermally developed on iron aluminide alloys

    SciTech Connect

    Natesan, K.; Klug, K.L.; Renusch, D.; Grimsditch, M.; Veal, B.W.

    1996-05-01

    Several alumina-forming Fe-Al intermetallic alloys have been oxidized in oxygen for 100 h at 1000 C to understand the scaling kinetics, scale morphology, scale adhesion, and strain accommodation in the scales. Oxidation studies were conducted by thermogravimetry, followed by analyses of the surfaces of oxide scales. In addition, samples were cooled to 77 K and then fractured; then, their scale/metal interfaces were analyzed. Some of the scales were adhesion-tested by applying a tensile load to pull the scale away from the substrate. Finally, ruby fluorescence was used to measure in-plane strains in the oxide scales and values correlated with scale microstructures.

  4. Rapid fabrication of self-ordered porous alumina with 10-/sub-10-nm-scale nanostructures by selenic acid anodizing.

    PubMed

    Nishinaga, Osamu; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O

    2013-01-01

    Anodic porous alumina has been widely investigated and used as a nanostructure template in various nanoapplications. The porous structure consists of numerous hexagonal cells perpendicular to the aluminum substrate and each cell has several tens or hundreds of nanoscale pores at its center. Because the nanomorphology of anodic porous alumina is limited by the electrolyte during anodizing, the discovery of additional electrolytes would expand the applicability of porous alumina. In this study, we report a new self-ordered nanoporous alumina formed by selenic acid (H2SeO4) anodizing. By optimizing the anodizing conditions, anodic alumina possessing 10-nm-scale pores was rapidly assembled (within 1 h) during selenic acid anodizing without any special electrochemical equipment. Novel sub-10-nm-scale spacing can also be achieved by selenic acid anodizing and metal sputter deposition. Our new nanoporous alumina can be used as a nanotemplate for various nanostructures in 10-/sub-10-nm-scale manufacturing. PMID:24067318

  5. Finite element modeling of the effect of interface anomalies on thermal stresses in alumina scales

    SciTech Connect

    Wright, J.K.; Williamson, R.L.; Hou, P.Y.; Cannon, R.M.; Renusch, D.; Veal, B.; Grimsditch, M.

    1998-07-01

    The scales that grow from oxidation often develop a convoluted morphology or interface pores. High thermal stresses can develop locally and are potentially detrimental to the scale or interface integrity. Finite element simulations are used to examine residual thermal stresses and strains that result when these deviations from a flat interface have formed, and the resulting geometry is subsequently cooled to room temperature. A variety of geometries will be considered for alumina scales on a FeCrAl substrate.

  6. Finite element modeling of the effect of interface anomalies on thermal stresses in alumina scales.

    SciTech Connect

    Wright, J. K.

    1998-06-10

    The scales that grow from oxidation often develop a convoluted morphology or interface pores. High thermal stresses can develop locally and are potentially detrimental to the scale or interface integrity. Finite element simulations are used to examine residual thermal stresses and strains that result when these deviations from a flat interface have formed, and the resulting geometry is subsequently cooled to room temperature. A variety of geometries will be considered for alumina scales on a FeCrAl substrate.

  7. Development and Exploratory Scale-Up of Alumina-Forming Austenitic (AFA) Stainless Steels

    SciTech Connect

    Brady, Michael P; Magee, John H; Yamamoto, Yukinori; Maziasz, Philip J; Santella, Michael L; Pint, Bruce A; Bei, Hongbin

    2009-01-01

    This paper presents the results of the continued development of creep-resistant, alumina-forming austenitic (AFA) stainless steel alloys, which exhibit a unique combination of excellent oxidation resistance via protective alumina (Al2O3) scale formation and high-temperature creep strength through the formation of stable nano-scale MC carbides and intermetallic precipitates. Efforts in fiscal year 2009 focused on the characterization and understanding of long-term oxidation resistance and tensile properties as a function of alloy composition and microstructure. Computational thermodynamic calculations of the austenitic matrix phase composition and the volume fraction of MC, B2-NiAl, and Fe2(Mo,Nb) base Laves phase precipitates were used to interpret oxidation behavior. Of particular interest was the enrichment of Cr in the austenitic matrix phase by additions of Nb, which aided the establishment and maintenance of alumina. Higher levels of Nb additions also increased the volume fraction of B2-NiAl precipitates, which served as an Al reservoir during long-term oxidation. Ageing studies of AFA alloys were conducted at 750C for times up to 2000 h. Ageing resulted in near doubling of yield strength at room temperature after only 50 h at 750C, with little further increase in yield strength out to 2000 h of ageing. Elongation was reduced on ageing; however, levels of 15-25% were retained at room temperature after 2000 h of total ageing.

  8. Dispersion Caused by Carbon Dioxide During Secondary Alumina Dissolution: A Lab-Scale Research

    NASA Astrophysics Data System (ADS)

    Yang, Youjian; Gao, Bingliang; Wang, Zhaowen; Shi, Zhongning; Hu, Xianwei; Yu, Jiangyu

    2014-06-01

    Secondary alumina is the byproduct of dry scrubbing in aluminum smelting. Secondary alumina has superior dissolution characteristics to primary alumina. Secondary alumina dissolves in pieces in molten cryolite, which results in larger contact area and better diffusion kinetics. In this work, the dissolution phenomenon of primary alumina, secondary alumina, and primary alumina doped with sodium carbonate or calcium carbonate (mass ratio = 10:1, 20:1) was observed and compared to estimate carbon-induced dispersion in industrial secondary alumina. Temperature fluctuations during sample dissolution were measured to evaluate the benefits of preheating on alumina dissolution. It was found that carbon mixed in secondary alumina significantly influences the dispersion of alumina particles at the moment of feeding, and thermodynamic analysis also shows that the combustion heat from carbon facilitates dispersion.

  9. Moisture-Induced Spallation and Interfacial Hydrogen Embrittlement of Alumina Scales

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2005-01-01

    Thermal expansion mismatch stresses and interfacial sulfur activity are the major factors producing primary Al2O3 scale spallation on high temperature alloys. However, moisture-induced delayed spallation appears as a secondary, but often dramatic, illustration of an additional mechanistic detail. A historical review of delayed failure of alumina scales and TBC s on superalloys is presented herein. Similarities with metallic phenomena suggest that hydrogen embrittlement from ambient humidity, resulting from the reaction Al+3H2O=Al(OH)3+3H(+)+3e(-), is the operative mechanism. This proposal was tested by standard cathodic hydrogen charging in 1N H2SO4, applied to Rene N5 pre-oxidized at 1150 C for 1000 1-hr cycles, and monitored by weight change, induced current, and microstructure. Here cathodic polarization at -2.0 V abruptly stripped mature Al2O3 scales at the oxide-metal interface. Anodic polarization at +2.0 V, however, produced alloy dissolution. Finally, with no applied voltage, the electrolyte alone produced neither scale spallation nor alloy dissolution. These experiments thus highlight the detrimental effects of hydrogen charging on alumina scale adhesion. It is proposed that interfacial hydrogen embrittlement is produced by moist air and is the root cause of both moisture-induced, delayed scale spallation and desktop TBC failures.

  10. Ultra-high density single nanometer-scale anodic alumina nanofibers fabricated by pyrophosphoric acid anodizing.

    PubMed

    Kikuchi, Tatsuya; Nishinaga, Osamu; Nakajima, Daiki; Kawashima, Jun; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O

    2014-01-01

    Anodic oxide fabricated by anodizing has been widely used for nanostructural engineering, but the nanomorphology is limited to only two oxides: anodic barrier and porous oxides. Therefore, the discovery of an additional anodic oxide with a unique nanofeature would expand the applicability of anodizing. Here we demonstrate the fabrication of a third-generation anodic oxide, specifically, anodic alumina nanofibers, by anodizing in a new electrolyte, pyrophosphoric acid. Ultra-high density single nanometer-scale anodic alumina nanofibers (10(10) nanofibers/cm(2)) consisting of an amorphous, pure aluminum oxide were successfully fabricated via pyrophosphoric acid anodizing. The nanomorphologies of the anodic nanofibers can be controlled by the electrochemical conditions. Anodic tungsten oxide nanofibers can also be fabricated by pyrophosphoric acid anodizing. The aluminum surface covered by the anodic alumina nanofibers exhibited ultra-fast superhydrophilic behavior, with a contact angle of less than 1°, within 1 second. Such ultra-narrow nanofibers can be used for various nanoapplications including catalysts, wettability control, and electronic devices. PMID:25491282

  11. Ultra-High Density Single Nanometer-Scale Anodic Alumina Nanofibers Fabricated by Pyrophosphoric Acid Anodizing

    NASA Astrophysics Data System (ADS)

    Kikuchi, Tatsuya; Nishinaga, Osamu; Nakajima, Daiki; Kawashima, Jun; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

    2014-12-01

    Anodic oxide fabricated by anodizing has been widely used for nanostructural engineering, but the nanomorphology is limited to only two oxides: anodic barrier and porous oxides. Therefore, the discovery of an additional anodic oxide with a unique nanofeature would expand the applicability of anodizing. Here we demonstrate the fabrication of a third-generation anodic oxide, specifically, anodic alumina nanofibers, by anodizing in a new electrolyte, pyrophosphoric acid. Ultra-high density single nanometer-scale anodic alumina nanofibers (1010 nanofibers/cm2) consisting of an amorphous, pure aluminum oxide were successfully fabricated via pyrophosphoric acid anodizing. The nanomorphologies of the anodic nanofibers can be controlled by the electrochemical conditions. Anodic tungsten oxide nanofibers can also be fabricated by pyrophosphoric acid anodizing. The aluminum surface covered by the anodic alumina nanofibers exhibited ultra-fast superhydrophilic behavior, with a contact angle of less than 1°, within 1 second. Such ultra-narrow nanofibers can be used for various nanoapplications including catalysts, wettability control, and electronic devices.

  12. Ultra-High Density Single Nanometer-Scale Anodic Alumina Nanofibers Fabricated by Pyrophosphoric Acid Anodizing

    PubMed Central

    Kikuchi, Tatsuya; Nishinaga, Osamu; Nakajima, Daiki; Kawashima, Jun; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

    2014-01-01

    Anodic oxide fabricated by anodizing has been widely used for nanostructural engineering, but the nanomorphology is limited to only two oxides: anodic barrier and porous oxides. Therefore, the discovery of an additional anodic oxide with a unique nanofeature would expand the applicability of anodizing. Here we demonstrate the fabrication of a third-generation anodic oxide, specifically, anodic alumina nanofibers, by anodizing in a new electrolyte, pyrophosphoric acid. Ultra-high density single nanometer-scale anodic alumina nanofibers (1010 nanofibers/cm2) consisting of an amorphous, pure aluminum oxide were successfully fabricated via pyrophosphoric acid anodizing. The nanomorphologies of the anodic nanofibers can be controlled by the electrochemical conditions. Anodic tungsten oxide nanofibers can also be fabricated by pyrophosphoric acid anodizing. The aluminum surface covered by the anodic alumina nanofibers exhibited ultra-fast superhydrophilic behavior, with a contact angle of less than 1°, within 1 second. Such ultra-narrow nanofibers can be used for various nanoapplications including catalysts, wettability control, and electronic devices. PMID:25491282

  13. Adherent Al2O3 scales formed on undoped NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    1987-01-01

    Changes in the spalling behavior of Al2O3 scales formed on an undoped NiCrAl alloy are described. Two samples of Ni-15Cr-13Al (wt pct), one a control and the other sanded, were subjected to 25 oxidation cycles. It is observed that adherent scales formed on the sanded sample; however, the control sample had speckled, spalled scales. The data reveal that the adherent scales are caused by repeated removal of surface layers after each oxidation cycle. It is determined that interfacial segregation of sulfur influences spallation and sulfur removal increases bonding. The effect of moisture on scale adhesions is investigated.

  14. Rapid fabrication of self-ordered porous alumina with 10-/sub-10-nm-scale nanostructures by selenic acid anodizing

    PubMed Central

    Nishinaga, Osamu; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2013-01-01

    Anodic porous alumina has been widely investigated and used as a nanostructure template in various nanoapplications. The porous structure consists of numerous hexagonal cells perpendicular to the aluminum substrate and each cell has several tens or hundreds of nanoscale pores at its center. Because the nanomorphology of anodic porous alumina is limited by the electrolyte during anodizing, the discovery of additional electrolytes would expand the applicability of porous alumina. In this study, we report a new self-ordered nanoporous alumina formed by selenic acid (H2SeO4) anodizing. By optimizing the anodizing conditions, anodic alumina possessing 10-nm-scale pores was rapidly assembled (within 1 h) during selenic acid anodizing without any special electrochemical equipment. Novel sub-10-nm-scale spacing can also be achieved by selenic acid anodizing and metal sputter deposition. Our new nanoporous alumina can be used as a nanotemplate for various nanostructures in 10-/sub-10-nm-scale manufacturing. PMID:24067318

  15. Moisture-Induced Delayed Alumina Scale Spallation on a Ni(Pt)Al Coating

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2009-01-01

    Delayed interfacial scale failure takes place after cooling for samples of a Ni(Pt)Al-coated CMSX4 single crystal superalloy, cycled at 1150 C for up to 2000 hr. One sample exhibited premature coating grain boundary wrinkling, alumina scale spallation to bare metal, and a final weight loss of 3.3 mg/cm2 . Spallation under ambient conditions was monitored with time after cooldown and was found to continue for 24 hr. This produced up to 0.05 mg/cm2 additional loss for each hold, accumulating 0.7 mg/cm 2 (20 percent of the total) over the course of the test. After test termination, water immersion produced an additional 0.15 mg/cm2 loss. (A duplicate sample produced much less wrinkling and time dependent spalling, maintaining a net weight gain.) The results are consistent with the general phenomena of moisture-induced delayed spallation (MIDS) of mature, distressed alumina scales formed on oxidation resistant M-Al alloys. Relative ambient humidity is discussed as the factor controlling adsorbed moisture, reaction with the substrate, and hydrogen effects on interface strength.

  16. Therapeutic adherence and competence scales for Developmentally Adapted Cognitive Processing Therapy for adolescents with PTSD

    PubMed Central

    Gutermann, Jana; Schreiber, Franziska; Matulis, Simone; Stangier, Ulrich; Rosner, Rita; Steil, Regina

    2015-01-01

    Background The assessment of therapeutic adherence and competence is often neglected in psychotherapy research, particularly in children and adolescents; however, both variables are crucial for the interpretation of treatment effects. Objective Our aim was to develop, adapt, and pilot two scales to assess therapeutic adherence and competence in a recent innovative program, Developmentally Adapted Cognitive Processing Therapy (D-CPT), for adolescents suffering from posttraumatic stress disorder (PTSD) after childhood abuse. Method Two independent raters assessed 30 randomly selected sessions involving 12 D-CPT patients (age 13–20 years, M age=16.75, 91.67% female) treated by 11 therapists within the pilot phase of a multicenter study. Results Three experts confirmed the relevance and appropriateness of each item. All items and total scores for adherence (intraclass correlation coefficients [ICC]=0.76–1.00) and competence (ICC=0.78–0.98) yielded good to excellent inter-rater reliability. Cronbach's alpha was 0.59 for the adherence scale and 0.96 for the competence scale. Conclusions The scales reliably assess adherence and competence in D-CPT for adolescent PTSD patients. The ratings can be helpful in the interpretation of treatment effects, the assessment of mediator variables, and the identification and training of therapeutic skills that are central to achieving good treatment outcomes. Both adherence and competence will be assessed as possible predictor variables for treatment success in future D-CPT trials. PMID:25791915

  17. Moisture-induced delayed spallation and interfacial hydrogen embrittlement of alumina scales

    NASA Astrophysics Data System (ADS)

    Smialek, James L.

    2006-01-01

    While interfacial sulfuris the primary chemical factor affecting Al2O3 scale adhesion, moisture-induced delayed spallation appears as a secondary, but impressive, mechanistic detail. Similarities with bulk metallic phenomena suggest that hydrogen embrittlement from ambient humidity, resulting from the reaction Alalloy+3(H2O)air=Al(OH)- 3+3H+ may be the operative mechanism. This proposal was tested on pre-oxidized René N5 by standard cathodic hydrogen charging in 1N H2SO4, as monitored by weight change, induced current, and microstructure. Cathodic polarization at -2.0 V abruptly stripped mature Al2O3 scales at the oxide-metal interface. Anodic polarization at +2.0V, however, produced alloy dissolution. Finally, with no applied voltage, the acid electrolyte produced neither scale spallation nor alloy dissolution. Thus, hydrogen charging was detrimental to alumina scale adhesion. Moisture-induced interfacial hydrogen embrittlement is concluded to be the cause of delayed scale spallation and desktop thermal barrier coating failures.

  18. Moisture-Induced Delayed Spallation and Interfacial Hydrogen Embrittlement of Alumina Scales

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2008-01-01

    While interfacial sulfur is the primary chemical factor affecting Al2O3 scale adhesion, moisture-induced delayed spallation appears as a secondary, but impressive, mechanistic detail. Similarities with bulk metallic phenomena suggest that hydrogen embrittlement from ambient humidity, resulting from the reaction Al(sub alloy)+3(H2O)(sub air) = Al(OH)(-) (sub 3) +3H(+) may be the operative mechanism. This proposal was tested on pre-oxidized Rene N5 by standard cathodic hydrogen charging in 1N H2SO4, as monitored by weight change, induced current, and microstructure. Cathodic polarization at -2.0 V abruptly stripped mature Al2O3 scales at the oxide-metal interface. Anodic polarization at +2.0 V, however, produced alloy dissolution. Finally, with no applied voltage, the acid electrolyte produced neither scale spallation nor alloy dissolution. Thus, hydrogen charging was detrimental to alumina scale adhesion. Moisture-induced interfacial hydrogen embrittlement is concluded to be the cause of delayed scale spallation and desktop thermal barrier coating failures.

  19. Oxygen Permeability and Grain-Boundary Diffusion Applied to Alumina Scales

    NASA Technical Reports Server (NTRS)

    Smialek, James L.; Jacobson, Nathan S.; Gleeson, Brian; Hovis, David B.; Heuer, Arthur H.

    2013-01-01

    High-temperature oxygen permeability measurements had determined grain-boundary diffusivities (deltaD(sub gb)) in bulk polycrystalline alumina (Wada, Matsudaira, and Kitaoka). They predict that oxygen deltaD(sub gb,O) varies with oxygen pressure as P(O2)(sup -1/6) at low pressure whereas aluminum deltaD(sub gb),Al varies with P(O2)(sup +3/16) at high pressure. These relations were used to evaluate alumina scale growth in terms of diffusivity and grain size. A modified Wagner treatment for dominant inward oxygen growth produces the concise solution: ?(sub i) = k(sub p,i)×G(sub i) = 12 deltaD(sub gb,O,int), where ?(sub i) is a constant and k(sub p,i) and G(sub i) refer to instantaneous values of the scale parabolic growth constant and grain size, respectively. A commercial FeCrAl(Zr) alloy was oxidized at 1100 to 1400 degC to determine k(sub p,i), interfacial grain size, ?, and thus deltaD(sub gb,O,int). The deltaD(sub gb,O,int) values predicted from oxidation at (375 kJ/mole) were about 20 times less than those obtained above (at 298 kJ/mole), but closer than extrapolations from high-temperature bulk measurements. The experimental oxidation results agree with similar FeCrAl(X) studies, especially where both k(sub p,i) and G(sub i) were characterized. This complete approach accounts for temperature-sensitive oxidation effects of grain enlargement, equilibrium interface pressure variation, and grain-boundary diffusivity.

  20. Validation of the Adherence Determinants Questionnaire scale among women with breast and cervical cancer1

    PubMed Central

    Lessa, Paula Renata Amorim; Ribeiro, Samila Gomes; Aquino, Priscila de Souza; de Almeida, Paulo Cesar; Pinheiro, Ana Karina Bezerra

    2015-01-01

    Objectives: the aim was to translate and culturally adapt the Adherence Determinants Questionnaire scale for the Portuguese language in the Brazilian context, and to check its reliability and validity to analyze the elements of the adherence of patients to the clinical treatment for breast and cervical cancer. Method: this was a methodological study, carried out in two oncology reference centers. The sample consisted of 198 participants, with 152 being treated for breast cancer and 46 being treated for cervical cancer. The content validation was performed by a committee of experts. The construct validation was demonstrated through factor analysis and the reliability was analyzed using Cronbach's alpha. Results: the committee of experts made the necessary adjustments so that the scale was adapted to the Brazilian context. The factor analysis suggested a reduction from seven to five factors and the maintenance of 38 items similar to those of the original scale. The reliability, investigated through Cronbach's alpha, was .829, showing high internal consistency. Conclusion: it was concluded that the Brazilian version of the Adherence Determinants Questionnaire scale is a valid and reliable instrument that is able to measure the elements of adherence to the treatment for breast and cervical cancer. PMID:26487149

  1. The Scale of Self-Efficacy Expectations of Adherence to Antiretroviral Treatment: A Tool for Identifying Risk for Non-Adherence to Treatment for HIV

    PubMed Central

    Drachler, Maria de Lourdes; Drachler, Carlos Wietzke; Teixeira, Luciana Barcellos; de Carvalho Leite, José Carlos

    2016-01-01

    Background Identification of risk for non-adherence to treatment is a challenge for personalized care for people living with HIV. Standardized questionnaires of patients’ expectations of their capability to overcome obstacles for treatment adherence may be used as a pre-screening for risk identification. A scale of self-efficacy expectations of adherence to antiretroviral treatment (SEA-ART scale) was previously developed. This study assesses the scale validity in predicting non-adherence to ART in adults living with HIV. Methods and Findings A prospective cohort study applied a 21-item SEA-ART scale to 275 adults in ART treatment at an outpatient public service for HIV in Southern Brazil. ART medications taken were assessed at one-month follow-up; ART adherence was devised as an intake of 95% and more of the prescribed medication. A SEA-ART score was calculated by adding up the scores of all items. Multivariable logistic regression and the Area Under the Receiver-Operating-Characteristic Curve (AUROC) were applied to examine the ability of the SEA-ART score to predict non-adherence at follow-up. The SEA-ART score varied from 21 to 105; mean 93.9; median 103.0. Non-adherence was 30.3% (n = 81/267). The odds of non-adherence was 8% lower for each unit increase of the SEA-ART score; after adjustment for age, sex, formal education and time in treatment (OR = 0.92; 95%CI 0.90–0.95; LRT for linear trend, p = 0.002). The AUROC was 0.80 (95%CI 0.73–0.87; p<0.001). The SEA-ART optimal cut-off value was 101, providing a sensitivity of 76.5%, a specificity of 73.1%, a positive predictive value of 55.4% and a negative predictive value of 87.7%. There was no evidence of difference in sensitivity, and specificity among groups organized by age, gender, formal education and time in treatment. Conclusions The SEA-ART scale appears to have a good capacity to discriminate between adherents and non-adherents at one-month follow-up. Further studies should confirm these results

  2. Growth strains and stress relaxation in alumina scales during high temperature oxidation

    SciTech Connect

    Hou, P.Y.; Paulikas, A.P.; Veal, B.W.

    2004-03-23

    A novel X-ray technique was used, exploiting synchrotron radiation at the Advanced Photon Source at Argonne National Laboratory, to investigate the growth stresses in {alpha}-Al{sub 2}O{sub 3}. In-situ measurements of Debye-Scherrer diffraction patterns from the scale were recorded during oxidation and cooling, and the elliptical distortion of the diffraction rings was analyzed to yield the in-plane strain. Fe-28Al, Fe-40Al, Fe-40Al-0.2Hf, Fe-20Cr-10Al and Ni-50Al (at. %) were studied. Data were acquired in air at temperatures between 950-1100 C and during cool down. In all cases, the steady stage growth strain was relatively low (<0.1%) and was either tensile or compressive depending on the alloy. A higher tensile strain often existed during the initial oxidation period when transition alumina was present. Thermal stresses imposed on NiAl by reducing the sample temperature to 950 C for a period of time showed noticeable stress relaxation by creep. Different degrees of relaxation were also found during cooling depending on alloy composition and scale microstructure. On all Fe-based alloys, the first formed {alpha}-Al{sub 2}O{sub 3} was highly textured with the degree of texture decreasing with further oxidation. The relationships between stress development, scale wrinkling, oxide phase changes, and the effect of reactive element addition on growth stresses are discussed. Results are compared with other reports of growth stresses in Al{sub 2}O{sub 3} scales.

  3. Highly efficient and large-scale fabrication of superhydrophobic alumina surface with strong stability based on self-congregated alumina nanowires.

    PubMed

    Peng, Shan; Tian, Dong; Yang, Xiaojun; Deng, Wenli

    2014-04-01

    In this study, a large-area superhydrophobic alumina surface with a series of superior properties was fabricated via an economical, simple, and highly effective one-step anodization process, and subsequently modified with low-surface-energy film. The effects of the anodization parameters including electrochemical anodization time, current density, and electrolyte temperature on surface morphology and surface wettability were investigated in detail. The hierarchical alumina pyramids-on-pores (HAPOP) rough structure which was produced quickly through the one-step anodization process together with a low-surface-energy film deposition [1H,1H,2H,2H-perfluorodecyltriethoxysilane (PDES) and stearic acid (STA)] confer excellent superhydrophobicity and an extremely low sliding angle. Both the PDES-modified superhydrophobic (PDES-MS) and the STA-modified superhydrophobic (STA-MS) surfaces present fascinating nonwetting and extremely slippery behaviors. The chemical stability and mechanical durability of the PDES-MS and STA-MS surfaces were evaluated and discussed. Compared with the STA-MS surface, the as-prepared PDES-MS surface possesses an amazing chemical stability which not only can repel cool liquids (water, HCl/NaOH solutions, around 25 °C), but also can show excellent resistance to a series of hot liquids (water, HCl/NaOH solutions, 30-100 °C) and hot beverages (coffee, milk, tea, 80 °C). Moreover, the PDES-MS surface also presents excellent stability toward immersion in various organic solvents, high temperature, and long time period. In particular, the PDES-MS surface achieves good mechanical durability which can withstand ultrasonication treatment, finger-touch, multiple fold, peeling by adhesive tape, and even abrasion test treatments without losing superhydrophobicity. The corrosion resistance and durability of the diverse-modified superhydrophobic surfaces were also examined. These fascinating performances makes the present method suitable for large-scale

  4. A relationship between indigenous impurity elements and protective oxide scale adherence characteristics

    NASA Astrophysics Data System (ADS)

    Smeggil, J. G.; Funkenbusch, A. W.; Bornstein, N. S.

    1986-06-01

    A new and a radically different mechanism to account for the beneficial effects that small additions of elements such as yttrium have on the adherence of oxide scales is proposed. It has been long:known and has been reaffirmed here that indigenous impurities such as sulfur, known to be present at tramp levels (<100 ppm) within nickel and nickel-based alloys, can segregate to metal surfaces. However, here it has been disclosed that such sulfur segregation can also markedly affect the adherence of the protective oxide scale. In the absence of elements like yttrium, such segregation effects weaken the bond between the protective scale and the substrate metal. The role of the yttrium is to interact with such indigenous sulfur to form a refractory sulfide. This interaction lessens the amount of sulfur available to segregate to and concentrate at the critical scale-metal interface. Results reported here have focused on sulfur because sulfur has been long known to be a common tramp impurity in nickel and nickel-based alloys. However other elements, e.g., phosphorus, chlorine, etc., could very probably produce similar effects. The results of experiments involving Auger spectroscopy, optical, scanning electron microscopy, scanning electron microprobe, and scanning transmission electron microscopy techniques in conjunction with isothermal and cyclic oxidation testing which have led us to propose this mechanism are presented.

  5. Accuracy of patient-reported adherence to glaucoma medications on a visual analog scale as compared with electronic monitors

    PubMed Central

    Sayner, Robyn; Carpenter, Delesha M.; Blalock, Susan J.; Robin, Alan L.; Muir, Kelly W.; Hartnett, Mary Elizabeth; Giangiacomo, Annette L.; Tudor, Gail; Sleath, Betsy

    2015-01-01

    Purpose Glaucoma medications can reduce intraocular pressure and improve clinical outcomes when patients adhere to their medication regimen. Providers often ask glaucoma patients to self-report their adherence, but the accuracy of this self-report method has received little scientific attention. Our purpose was to compare a self-report medication adherence measure with adherence data collected from Medication Event Monitoring Systems (MEMS) electronic monitors. Additionally, we sought to identify which patient characteristics were associated with over-reporting adherence on the self-reported measure. Methods English-speaking adult glaucoma patients were recruited for this observational cohort study from six ophthalmology practices. Patients were interviewed immediately after a baseline medical visit and were given MEMS containers, which were used to record adherence over a 60-day period. MEMS data were used to calculate percent adherence, which measured the percentage of the prescribed number of doses taken, and timing adherence, which assessed the percent doses taken on time. Patients self-reported adherence to their glaucoma medications on a visual analog scale (VAS) approximately 60 days following the baseline visit. Bivariate analyses and logistic regressions were used to analyze the data. Self-reported medication adherence on the VAS was plotted against MEMS adherence to illustrate the level of discrepancy between self-reported and electronically-monitored adherence. Findings The analyses included 240 patients who returned their MEMS containers and who self-reported medication adherence at the 60-day follow-up visit. When compared with MEMS-measured percent adherence, 31% of patients (n=75) over-estimated their adherence on the VAS. When compared with MEMS-measured timing adherence, 74% (n=177) of patients over-estimated their adherence on the VAS. For the MEMS-measured percent adherence, logistic regression revealed that patients who were newly prescribed

  6. The Malaysian Medication Adherence Scale (MALMAS): Concurrent Validity Using a Clinical Measure among People with Type 2 Diabetes in Malaysia

    PubMed Central

    Lai, Pauline Siew Mei; Morisky, Donald E.

    2015-01-01

    Medication non-adherence is a prevalent problem worldwide but up to today, no gold standard is available to assess such behavior. This study was to evaluate the psychometric properties, particularly the concurrent validity of the English version of the Malaysian Medication Adherence Scale (MALMAS) among people with type 2 diabetes in Malaysia. Individuals with type 2 diabetes, aged 21 years and above, using at least one anti-diabetes agent and could communicate in English were recruited. The MALMAS was compared with the 8-item Morisky Medication Adherence Scale (MMAS-8) to assess its convergent validity while concurrent validity was evaluated based on the levels of glycated hemoglobin (HbA1C). Participants answered the MALMAS twice: at baseline and 4 weeks later. The study involved 136 participants. The MALMAS achieved acceptable internal consistency (Cronbach’s alpha=0.565) and stable reliability as the test-retest scores showed fair correlation (Spearman’s rho=0.412). The MALMAS has good correlation with the MMAS-8 (Spearman’s rho=0.715). Participants who were adherent to their anti-diabetes medications had significantly lower median HbA1C values than those who were non-adherence (7.90 versus 8.55%, p=0.032). The odds of participants who were adherent to their medications achieving good glycemic control was 3.36 times (95% confidence interval: 1.09-10.37) of those who were non-adherence. This confirms the concurrent validity of the MALMAS. The sensitivity of the MALMAS was 88.9% while its specificity was 29.6%. The findings of this study further substantiates the reliability and validity of the MALMAS, in particular its concurrent validity and sensitivity for assessing medication adherence of people with type 2 diabetes in Malaysia. PMID:25909363

  7. Validation of the Persian Version of the 8-Item Morisky Medication Adherence Scale (MMAS-8) in Iranian Hypertensive Patients.

    PubMed

    Moharamzad, Yashar; Saadat, Habibollah; Nakhjavan Shahraki, Babak; Rai, Alireza; Saadat, Zahra; Aerab-Sheibani, Hossein; Naghizadeh, Mohammad Mehdi; Morisky, Donald E

    2015-01-01

    The reliability and validity of the 8-item Morisky Medication Adherence Scale (MMAS-8) was assessed in a sample of Iranian hypertensive patients. In this multi-center study which lasted from August to October 2014, a total of 200 patients who were suffering from hypertension (HTN) and were taking anti-hypertensive medication(s) were included. The cases were accessed through private and university health centers in the cities of Tehran, Karaj, Kermanshah, and Bafgh in Iran and were interviewed face-to-face by the research team. The validated Persian translation of the MMAS-8 was provided by the owner of this scale. This scale contains 7 questions with "Yes" or "No" response choices and an additional Likert-type question (totally 8 questions). The total score ranges from 0 to 8 with higher scores reflecting better medication adherence. Mean (±SD) overall MMAS-8 score was 5.57 (±1.86). There were 108 (54%), 62 (31%), and 30 (15%) patients in the low, moderate, and high adherence groups. Internal consistency was acceptable with an overall Cronbach's ? coefficient of 0.697 and test-retest reliability showed good reproducibility (r= 0.940); P< 0.001. Overall score of the MMAS-8 was significantly correlated with systolic BP (r= - 0.306) and diastolic BP (r= - 0.279) with P< 0.001 for both BP measurements. The Chi-square test showed a significant relationship between adherence level and BP control (P= 0.016). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the scale were 92.8%, 22.3%, 52.9%, and 76.7%, respectively. The Persian version of the MMAS had acceptable reliability and validity in Iranian hypertensive patients. This scale can be used as a standard and reliable tool in future studies to determine medication adherence of Persian-speaking patients with chronic conditions. PMID:25946926

  8. Formation of α-alumina scales in the Fe-Al(Cr) diffusion coating on China low activation martensitic steel

    NASA Astrophysics Data System (ADS)

    Zhan, Qin; Zhao, Weiwei; Yang, Hongguang; Hatano, Yuji; Yuan, Xiaoming; Nozaki, Teo; Zhu, Xinxin

    2015-09-01

    To study the formation mechanism of stable α-Al2O3 scales, the oxidation behavior of Fe-Al(Cr) diffusion coating on China low activation martensitic steel has been investigated under the oxygen partial pressure ranging from 1 to 20,000 Pa at 1253 K. A single, continuous Al2O3 scale with the maximum thickness of about 2000 nm was formed on the Fe-Al(Cr) diffusion layer. The phase transformation of alumina scales on the surface of Fe-Al(Cr) layer was studied at different oxidation times ranging from 3 to 180 min. With the increase in oxygen partial pressure, the phase transformation time of α-Al2O3 is decreased. The metastable γ-Al2O3 and transition α-(Al0.948Cr0.052)2O3 phases were formed in the earlier oxidation process and finally transformed to the stable α-Al2O3 phase, which were detected by grazing incidence angle X-ray diffraction and confirmed by transmission electron microscopy. This implies that Cr shows the third element effect and serves as a template for the nucleation of the stable α-Al2O3.

  9. Scaling up human papillomavirus vaccination: a conceptual framework of vaccine adherence

    PubMed Central

    Katz, Ingrid T.; Ware, Norma C.; Gray, Glenda; Haberer, Jessica E.; Mellins, Claude A.; Bangsberg, David R.

    2011-01-01

    This review article provides a conceptual framework for human papillomavirus (HPV) vaccine acceptance and adherence, with a focus on improving understanding of the sociocultural factors impacting vaccine adherence behaviour. We include a systematic review of the slowly expanding literature on HPV vaccine acceptability and uptake in developed nations, as well as the relatively few publications from poorer nations, where more than 80% of global cervical cancer related deaths occur and where the vaccine will probably have the largest impact. We suggest that this conceptual framework will not only improve our understanding of HPV vaccine uptake and adherence, but it may also guide future sociobehavioural research geared towards improving adherence to the HPV vaccine and other multi-step vaccines in a young population at risk for sexually transmissible infections. PMID:20719215

  10. Optimal conditions for alumina coating formation on the MA956 superalloy for prosthetic bearing applications.

    PubMed

    Ruiz, J; Escudero, M L; Canahua, H; García-Alonso, M C

    1999-08-01

    An experimental study of the oxidation treatment at high temperature of the ODS MA956 superalloy was conducted in an attempt to achieve a protective alumina scale for biomedical applications. A quadratic response-surface model was developed in order to study the effects of treatment time and temperature (in the range of 1000 degrees C to 1250 degrees C) on scale thickness. The obtained model adequately represents the experimental response and shows that the thickness gradients of the layer increase with the temperature for each exposure time and decrease steadily to zero as the treatment time increases. The microstructural characterization reveals that the alumina scale formed at or above 1000 degrees C consists of an alpha-alumina phase. Treatments at temperatures above 1150 degrees C give rise to an alumina scale with some defect probability. An increase in the temperature up to 1200 degrees C gives rise to the appearance of some blistering of the superficial scale. An oxidation treatment of 100 h at 1100 degrees C was found to be the best for guaranteeing the formation of a defect-free, compact, adherent, and continuous alpha-alumina scale thick enough to support satisfactory wear and biological conditions. PMID:10379995

  11. Towards large scale preparation of graphene in molten salts and its use in the fabrication of highly toughened alumina ceramics.

    PubMed

    Kamali, Ali Reza; Feighan, John; Fray, Derek J

    2016-08-15

    Highly crystalline graphene nanosheets were reproducibly generated by the electrochemical exfoliation of graphite electrodes in molten LiCl containing protons. The graphene product has been successfully applied in several applications. This paper discusses the effect of molten salt produced graphene on the microstructures and mechanical properties of alumina articles produced by slip casting and pressureless sintering, which is one of the most convenient methods for the commercial production of alumina ceramics. In addition to graphene, graphite powder and multi-walled carbon nanotubes (CNTs) were also used to prepare alumina articles for comparative purposes. A graphene strengthening effect was realized through microstructural refinement and by influencing the formation of alumina nanorods during the sintering of α-Al2O3 articles. The fracture toughness of the sintered alumina articles increased to an impressive value of 6.98 MPa m(1/2) by adding 0.5 wt% graphene nanosheets. This was attributed to the unique microstructure obtained, comprised of micrometer sized alumina grains separated by alumina nanorods. PMID:27231211

  12. Feasibility and process scale-up low cost alumina fibers for advanced Re-usable Surface Insulation (RSI)

    NASA Technical Reports Server (NTRS)

    Pearson, A.

    1975-01-01

    The objective of this program was to establish feasibility of a process to produce low cost aluminum oxide fibers having sufficient strength, flexibility, and thermal stability for multiple re-use at temperatures to 1480 C in advanced RSI type heat shields for reentry vehicles. Using bench-scale processing apparatus, the Alcoa 'Saphiber' process was successfully modified to produce nominally 8 microns diameter polycrystalline alpha-alumina fiber. Thermal stability was demonstrated in vacuum reheating tests to 1371 C and in atmospheric reheating to 1483 C. Individual fiber properties of strength, modulus, and flexibility were not determined because of friability and short length of the fiber. Rigidized tile produced from fiber of nominally 8, 20 and 40 micron diameter had thermal conductivities significantly higher than those of RSI SiO2 or mullite at relatively low temperature but became comparable above about 1000 C. Tile densities were high due to short fiber length, especially in the coarser diameter fiber. No significant effect of fiber diameter on thermal properties could be determined form the data. Mechanical properties of tiles deteriorated as fiber diameter increased.

  13. Validation of the Persian Version of the 8-Item Morisky Medication Adherence Scale (MMAS-8) in Iranian Hypertensive Patients

    PubMed Central

    Moharamzad, Yashar; Saadat, Habibollah; Shahraki, Babak Nakhjavan; Rai, Alireza; Saadat, Zahra; Aerab-Sheibani, Hossein; Naghizadeh, Mohammad Mehdi; Morisky, Donald E.

    2015-01-01

    The reliability and validity of the 8-item Morisky Medication Adherence Scale (MMAS-8) was assessed in a sample of Iranian hypertensive patients. In this multi-center study which lasted from August to October 2014, a total of 200 patients who were suffering from hypertension (HTN) and were taking anti-hypertensive medication(s) were included. The cases were accessed through private and university health centers in the cities of Tehran, Karaj, Kermanshah, and Bafgh in Iran and were interviewed face-to-face by the research team. The validated Persian translation of the MMAS-8 was provided by the owner of this scale. This scale contains 7 questions with “Yes” or “No” response choices and an additional Likert-type question (totally 8 questions). The total score ranges from 0 to 8 with higher scores reflecting better medication adherence. Mean (±SD) overall MMAS-8 score was 5.57 (±1.86). There were 108 (54%), 62 (31%), and 30 (15%) patients in the low, moderate, and high adherence groups. Internal consistency was acceptable with an overall Cronbach’s α coefficient of 0.697 and test–retest reliability showed good reproducibility (r= 0.940); P< 0.001. Overall score of the MMAS-8 was significantly correlated with systolic BP (r= - 0.306) and diastolic BP (r= - 0.279) with P< 0.001 for both BP measurements. The Chi-square test showed a significant relationship between adherence level and BP control (P= 0.016). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the scale were 92.8%, 22.3%, 52.9%, and 76.7%, respectively. The Persian version of the MMAS had acceptable reliability and validity in Iranian hypertensive patients. This scale can be used as a standard and reliable tool in future studies to determine medication adherence of Persian-speaking patients with chronic conditions. PMID:25946926

  14. Adaptation and evaluation of the measurement properties of the Brazilian version of the Self-efficacy for Appropriate Medication Adherence Scale1

    PubMed Central

    Pedrosa, Rafaela Batista dos Santos; Rodrigues, Roberta Cunha Matheus

    2016-01-01

    Objectives: to undertake the cultural adaptation of, and to evaluate the measurement properties of, the Brazilian version of the Self-efficacy for Appropriate Medication Adherence Scale in coronary heart disease (CHD) patients, with outpatient monitoring at a teaching hospital. Method: the process of cultural adaptation was undertaken in accordance with the international literature. The data were obtained from 147 CHD patients, through the application of the sociodemographic/clinical characterization instrument, and of the Brazilian versions of the Morisky Self-Reported Measure of Medication Adherence Scale, the General Perceived Self-Efficacy Scale, and the Self-efficacy for Appropriate Medication Adherence Scale. Results: the Brazilian version of the Self-efficacy for Appropriate Medication Adherence Scale presented evidence of semantic-idiomatic, conceptual and cultural equivalencies, with high acceptability and practicality. The floor effect was evidenced for the total score and for the domains of the scale studied. The findings evidenced the measure's reliability. The domains of the Brazilian version of the Self-efficacy for Appropriate Medication Adherence Scale presented significant inverse correlations of moderate to strong magnitude between the scores of the Morisky scale, indicating convergent validity, although correlations with the measure of general self-efficacy were not evidenced. The validity of known groups was supported, as the scale discriminated between "adherents" and "non-adherents" to the medications, as well as to "sufficient dose" and "insufficient dose". Conclusion: the Brazilian version of the Self-efficacy for Appropriate Medication Adherence Scale presented evidence of reliability and validity in coronary heart disease outpatients. PMID:27192417

  15. Evaluation of the Single-Item Self-Rating Adherence Scale for Use in Routine Clinical Care of People Living with HIV

    PubMed Central

    Feldman, BJ; Fredericksen, RJ; Crane, PK; Safren, SA; Mugavero, MJ; Willig, James H; Simoni, JM; Wilson, IB; Saag, MS; Kitahata, MM; Crane, HM

    2012-01-01

    The Self-Rating Scale Item (SRSI) is a single-item self-report adherence measure that uses adjectives in a 5-point Likert scale, from “very poor” to “excellent,” to describe medication adherence over the past 4 weeks. This study investigated the SRSI in 2,399 HIV-infected patients in routine care at two outpatient primary HIV clinics. Correlations between the SRSI and four commonly used adherence items ranged from 0.37–0.64. Correlations of adherence barriers, such as depression and substance use, were comparable across all adherence items. General estimating equations suggested the SRSI is as good as or better than other adherence items (p’s <0.001 vs. <0.001–0.99) at predicting adherence-related clinical outcomes, such as HIV viral load and CD4+ cell count. These results and the SRSI’s low patient burden suggest its routine use could be helpful for assessing adherence in clinical care and should be more widespread, particularly where more complex instruments may be impractical. PMID:23108721

  16. Validation of the Medication Adherence Rating Scale in homeless patients with schizophrenia: Results from the French Housing First experience

    PubMed Central

    Zemmour, K.; Tinland, A.; Boucekine, M.; Girard, V.; Loubière, S.; Resseguier, N.; Fond, G.; Auquier, P.; Boyer, L.; Apostolidis, T.; Birmes, P.; Bossetti, T.; Bouloudnine, R.; Combes, B.; Debieve, J.; Falissard, B.; Greacen, T.; Laval, C.; Lancon, C.; Le Cardinal, P.; Mantovani, J.; Moreau, D.; Naudin, J.; Rhunter, P.; Videau, B.

    2016-01-01

    The Medication Adherence Rating Scale (MARS) is one of the most widely used measurements of adherence in schizophrenia (SZ), but there is no available data regarding its psychometric properties in homeless SZ patients (HSZ). The aim of this study was therefore to assess the psychometric properties of the MARS in a large multicenter sample of HSZ subjects. This multi-centre prospective study was conducted in the following 4 French cities: Lille, Marseille, Paris and Toulouse. Three hundred and fifty-three patients were included. The 3-factor structure of the MARS was confirmed using confirmatory factor analysis: RMSEA = 0.045, CFI = 0.98, TLI = 0.97 and WRMR = 0.76. The unidimensionality of each factor was supported by the satisfactory INFIT statistics. Item internal consistencies were all higher than 0.20 and the Kuder–Richardson were higher than to 0.6, except for factor 2, which was closed to 0.5. Significant associations with symptoms, functioning and quality of life showed satisfactory external validity. The acceptability was satisfactory with missing data lower than 5% for each dimension. The MARS is a short self-administered instrument with acceptable psychometric properties in homeless SZ patients that yields interesting information about medication adherence. PMID:27534796

  17. Validation of the Medication Adherence Rating Scale in homeless patients with schizophrenia: Results from the French Housing First experience.

    PubMed

    Zemmour, K; Tinland, A; Boucekine, M; Girard, V; Loubière, S; Resseguier, N; Fond, G; Auquier, P; Boyer, L

    2016-01-01

    The Medication Adherence Rating Scale (MARS) is one of the most widely used measurements of adherence in schizophrenia (SZ), but there is no available data regarding its psychometric properties in homeless SZ patients (HSZ). The aim of this study was therefore to assess the psychometric properties of the MARS in a large multicenter sample of HSZ subjects. This multi-centre prospective study was conducted in the following 4 French cities: Lille, Marseille, Paris and Toulouse. Three hundred and fifty-three patients were included. The 3-factor structure of the MARS was confirmed using confirmatory factor analysis: RMSEA = 0.045, CFI = 0.98, TLI = 0.97 and WRMR = 0.76. The unidimensionality of each factor was supported by the satisfactory INFIT statistics. Item internal consistencies were all higher than 0.20 and the Kuder-Richardson were higher than to 0.6, except for factor 2, which was closed to 0.5. Significant associations with symptoms, functioning and quality of life showed satisfactory external validity. The acceptability was satisfactory with missing data lower than 5% for each dimension. The MARS is a short self-administered instrument with acceptable psychometric properties in homeless SZ patients that yields interesting information about medication adherence. PMID:27534796

  18. The characteristics of alumina scales formed on HVOF-sprayed MCrAlY coatings[High Velocity Oxygen Fuel

    SciTech Connect

    Toma, D.; Brandl, W.; Koester, U.

    2000-02-01

    HVOF MCrAlY (M = Ni, Co) coatings were isothermally oxidized in synthetic air between 850 and 1050 C for times up to 167 hr. During thermal spraying, aluminum and yttrium oxidized to form a fine oxide dispersion. The HVOF MCrAlY coatings exhibited a microstructure similar to ODS alloys. The fine dispersion consisted of Al{sub 2}O{sub 3} and aluminum-yttrium oxides. The oxidation experiments showed that the oxidation rate of HVOF coatings was two times slower than the oxidation rate of VPS MCrAlY coatings. The oxidation mechanism changed mainly in the transient-stage (no metastable modification of Al{sub 2}O{sub 3} formed) and it was assumed that the oxide dispersion hindered diffusion of various elements from the bulk material during oxidation. The formation of the fine oxide dispersion also influenced the adherence of the oxide scale. The microstructures of the transient oxide scales were examined by X-ray diffraction (XRD) scanning electron microscopy (SEM), and transmission electron microscopy (TEM).

  19. Tip-like anodic alumina

    NASA Astrophysics Data System (ADS)

    Sun, Q. W.; Ding, G. Q.; Li, Y. B.; Zheng, M. J.; Shen, W. Z.

    2007-05-01

    Porous anodic alumina membranes and various nanotips have been demonstrating individually their unique usefulness in current nanotechnology. We present a one-step electrochemical approach to fabricate nanoscale alumina tips (tip-like anodic alumina, TAA) in order to combine the benefits of porous anodic alumina and a nanoscale tip array. The realized TAA has an ordered tip surface with controllable aspect ratio and high sheet density of ~1011 cm-2. The formation of alumina nanotips is due to the heat-driven dissolution of the nanopore surface. We have further shown that the surface nanostructure in TAA leads to the wettability reversal, and preferred nucleation and growth during material deposition. The easy and large-scale fabrication of TAA makes it possible for novel nanodevice applications.

  20. Microstructure and Residual Stress of Alumina Scale Formed on Ti2AlC at High Temperature in Air

    SciTech Connect

    Byeon, J; Liu, j; Hopkins, m; Fischer, W; Park, K; Brady, Michael P; Radovic, Miladin; Sohn, Yong Ho

    2007-01-01

    Ti2AlC ternary carbide is being explored for various high temperature applications owing to its high strength at high temperatures, excellent thermal-shock resistance, and high electrical conductivity. In this study, isothermal oxidation at 1000 XC, 1200 XC, and 1400 XC for up to 25 hours, as well as 1,000 1-hour cyclic oxidation at 1200 XC were performed in air to examine the oxidation behavior of Ti2AlC. Characteristics of the oxide scale developed in air, including mass change, residual stress in the -Al2O3 scale, phase constituents and microstructure, were examined as functions of time and temperature by thermogravimetry, photostimulated luminescence, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy via focused ion beam in-situ lift-out. A continuous and adherent -Al2O3 scale underneath a discontinuous-transient rutile-TiO2 scale was identified in the oxide scale developed at 1000 XC and 1200 XC. At 1400 XC, Al2TiO5 was identified as the discontinuous-transient scale above the continuous and adherent -Al2O3 scale. The -Al2O3 scale thickened to more than 15 m after 25 hours of isothermal oxidation at 1400 XC, and after 1,000 1-hour cyclic oxidation at 1200 XC, yet remained adherent and protective. The compressive residual stress determined by photoluminescence for the -Al2O3 scale remained under 0.65 GPa for the specimens oxidized up to 1400 XC for 25 hours. The small magnitude of the compressive residual stress may impart the high spallation-resistance of the protective -Al2O3 scale developed on Ti2AlC.

  1. Evaluation of mechanical properties and biological response of an alumina-forming Ni-free ferritic alloy.

    PubMed

    González-Carrasco, J L; Ciapetti, G; Montealegre, M A; Pagani, S; Chao, J; Baldini, N

    2005-06-01

    PM 2000 is a Ni-free oxide dispersion strengthened Fe-20Cr-5Al alloy able to develop a fine, dense and tightly adherent alpha-alumina scale during high-temperature oxidation. Despite the high temperature involved during thermal oxidation (1100 degrees C), microstructural changes in the candidate material, a hot rolled product, hardly occurs. Consequently, the good mechanical properties of the as-received material are not significantly affected. Moreover, due to the high compressive residual stresses at the alumina scale, an increase in the fatigue limit from 500 to 530 MPa is observed. Such stresses also account for the high capability of the coating/metal system to withstand more than 1% tensile deformation without cracking. The biocompatibility of the alloy was assessed in comparison to commercial alumina. Saos-2 osteoblast-like cells were either challenged with PM 2000 particles, or seeded onto PM 2000 (with and without scale) solid samples. Viability, growth, and ALP release from cells were assessed after 3 or 7 days, while mineralization was checked at 18 days. This study has demonstrated that PM 2000 with and without scale are capable of supporting in vitro growth and function of osteoblast-like cells over a period of 18 days. Results from this study suggest that the resulting alumina/alloy system combines the good mechanical properties of the alloy with the superior biocompatibility of the alpha-alumina, for which there is very good clinical experience. PMID:15626434

  2. Developing a Small-scale De-fluoridation Filter for use in Rural Northern Ghana with Activated Alumina as the Sorbent

    NASA Astrophysics Data System (ADS)

    Craig, L.; Stillings, L. L.; Decker, D.; Thomas, J.

    2013-12-01

    reaction time). The F- loading onto activated alumina did not change with grain size. However time to equilibrium increased dramatically with a decrease in grain size - after one hour of reaction time, the larger grain size adsorbed only 59% of F-, while at the finer grain size 90% was adsorbed. Future work will determine the volume of high F- water that can be treated before activated alumina needs to be regenerated or changed. These data will be incorporated into the design of a small-scale F-1 adsorption filter in the study area, and will predict the longevity of activated alumina as the sorbent.

  3. Development of a new diabetes medication self-efficacy scale and its association with both reported problems in using diabetes medications and self-reported adherence

    PubMed Central

    Sleath, Betsy; Carpenter, Delesha M; Blalock, Susan J; Davis, Scott A; Hickson, Ryan P; Lee, Charles; Ferreri, Stefanie P; Scott, Jennifer E; Rodebaugh, Lisa B; Cummings, Doyle M

    2016-01-01

    Background Although there are several different general diabetes self-efficacy scales, there is a need to develop a self-efficacy scale that providers can use to assess patient’s self-efficacy regarding medication use. The purpose of this study was to: 1) develop a new diabetes medication self-efficacy scale and 2) examine how diabetes medication self-efficacy is associated with patient-reported problems in using diabetes medications and self-reported adherence. Patients and methods Adult English-speaking patients with type 2 diabetes were recruited from a family medicine clinic and a pharmacy in Eastern North Carolina, USA. The patients were eligible if they reported being nonadherent to their diabetes medicines on a visual analog scale. Multivariable regression was used to examine the relationship between self-efficacy and the number of reported diabetes medication problems and adherence. Results The diabetes medication self-efficacy scale had strong reliability (Cronbach’s alpha =0.86). Among a sample (N=51) of mostly African-American female patients, diabetes medication problems were common (6.1±3.1) and a greater number of diabetes medications were associated with lower medication adherence (odds ratio: 0.35; 95% confidence interval: 0.13, 0.89). Higher medication self-efficacy was significantly related to medication adherence (odds ratio: 1.17; 95% confidence interval: 1.05, 1.30) and inversely related to the number of self-reported medication problems (β=−0.13; P=0.006). Conclusion Higher diabetes medication self-efficacy was associated with fewer patient-reported medication problems and better medication adherence. Assessing medication-specific self-efficacy may help to identify medication-related problems that providers can help the patients address, potentially improving adherence and patient outcomes. PMID:27354769

  4. Developing a Small-Scale De-Fluoridation Filter for Use in Rural Northern Ghana with Activated Alumina As the Sorbent

    NASA Astrophysics Data System (ADS)

    Craig, L.; Stillings, L. L.

    2014-12-01

    reaction time, the larger grain size adsorbed only 59% of F-, while at the finer grain size 90% was adsorbed. Future work will determine the volume of high F- water that can be treated before activated alumina needs to be regenerated or changed. These data will aid in the design of a small-scale F- adsorption filter in the study area, and will predict the longevity of activated alumina as the sorbent.

  5. FEG-SEM investigation of α-alumina scales formed on FeCrAlY alloys oxidised at 1200° C

    NASA Astrophysics Data System (ADS)

    Al-Badairy, H.; Tatlock, G.; Fawcett, S.; Beahan, P.; Hunt, J.

    2005-05-01

    This work is part of an ongoing European funded project, “SMILER”, with the aim of improving the performance of alumina forming Fe-20Cr-5Al-Y alloys for high temperature industrial applications. One aspect of the project is to investigate the influence of additives on the oxidation behaviour of these alloys. During this study a LEO 1550 FESEM (field emission scanning electron microscope), equipped with INCA X-ray microanalysis facilities was used. Ultra-high-purity model alloys, where the levels of additives (Hf, Zr, Ti, Si, La and Y) were carefully controlled, and two commercial Aluchrom YHfAl and Kanthal AMPT alloys were oxidised at 1200° C for up to 3100h (100h/cycle). The YHfAl, (Y+Ti+Zr)- and (Y+Zr+Hf)-containing alloys showed the highest oxidation rates when oxidised, whereas the La-containing alloy showed the lowest oxidation rate. However, the La-containing alloy spalled the most, while the (Y+Zr+Hf)-containing and YHfAl alloys showed little spallation, and the additives appeared to have a major influence on the spallation of the α -alumina scale formed. On the alloys with La and Si respectively, the scale spalled at the scale/metal interface (adhesively), whereas on alloys containing (Y+Hf+Ti) and (Y+Hf+Zr) and the YHfAl alloy, the scale spalled mainly in a cohesive manner (within the scale). Also, the added elements affected the scale topography. In general the scale had a columnar structure at the scale/metal interface, whereas the grains were equiaxed at the scale/gas interface. However, in the case of YHfAl and (Y+Zr+Hf)-containing alloys, a sunflower type structure was observed in both fractured samples, in the regions where the scale spalled cohesively. Preliminary EDX analyses revealed that, in the case of YHfAl, for example, the center of the sunflower structure was rich in Mg. This suggests that there may be inhomogeneities in the metal substrate, prior to oxidation, where high concentrations of Mg increase the local oxide growth rate.

  6. Reliability and validity of a new Medication Adherence Rating Scale (MARS) for the psychoses.

    PubMed

    Thompson, K; Kulkarni, J; Sergejew, A A

    2000-05-01

    Medication compliance is one of the foremost problems affecting neuroleptic efficacy in psychiatric patients. To date, compliancy has most commonly been assessed with the Drug Attitude Inventory (DAI) developed by Hogan et al. (Hogan, T.P., Awad, A.G., Eastwood, R., 1983. A self-report scale predictive of drug compliance in schizophrenics: reliability and discriminative validity. Psychol. Med. 13, 177-183). The present study identified several deficiencies in the DAI. Using the partial credit version of the Item Response Theory measurement model, the DAI was refined with the aim of greater validity and clinical utility. The new inventory was administered to 66 patients, the majority of whom were diagnosed with schizophrenia. When available, lithium levels and carer ratings of compliance were also recorded and used to verify compliancy. The new inventory appears to be a valid and reliable measure of compliancy for psychoactive medications. PMID:10785582

  7. Assessing the Adherence to Guidelines of Media Reporting of Suicide Using a Novel Instrument--the "Risk of Imitative Suicide Scale" (RISc).

    PubMed

    Nutt, Rachel; Kidd, Brian; Matthews, Keith

    2015-06-01

    Media guidelines for reporting of suicide are considered important in suicide prevention because of the risk of "imitative" suicide. There are currently no established tools for the quantification of quality of reporting. We sought to develop and validate a quality assessment instrument-the Risk of Imitative Suicide Scale (RISc). The RISc appears capable of discriminating reliably between adherent and nonadherent articles. Our data suggest that adherence to guidelines is inconsistent, and there are major differences between web-based and print media. The RISc could be used to evaluate effectiveness and consistency of media engagement with suicide prevention strategies. PMID:25382433

  8. Oxide growth stress measurements and relaxation mechanisms for alumina scales grown on FeCrAlY: Oxide growth stress measurements and relaxation mechanisms

    SciTech Connect

    Tortorelli, P. F.; Specht, E. D.; More, K. L.; Hou, P. Y.

    2012-08-08

    Early-stage tensile stress evolution in α-Al2O3 scales during oxidation of FeCrAlY at 1000, 1050, 1100, and 1200 °C was monitored in situ by use of synchrotron radiation. Tensile stress development as a function of oxidation temperature indicated a dynamic interplay between stress generation and relaxation. An analysis of the time dependence of the data indicated that the observed relaxation of the initial tensile stress in the oxide scales at 1100 and 1200°C is dominated by creep in the α-Al2O3. A thin layer of a (Fe,Cr,Al) oxide was observed at the oxide-gas interface, consistent with a mechanism whereby the conversion of (Fe,Cr,Al)2O3 to α-Al2O3 produces an initial tensile stress in the alumina scale.

  9. Rethinking adherence.

    PubMed

    Steiner, John F

    2012-10-16

    In 2012, the Centers for Medicare & Medicaid Services (CMS) will introduce measures of adherence to oral hypoglycemic, antihypertensive, and cholesterol-lowering drugs into its Medicare Advantage quality program. To meet these quality goals, delivery systems will need to develop and disseminate strategies to improve adherence. The design of adherence interventions has too often been guided by the mistaken assumptions that adherence is a single behavior that can be predicted from readily available patient characteristics and that individual clinicians alone can improve adherence at the population level.Effective interventions require recognition that adherence is a set of interacting behaviors influenced by individual, social, and environmental forces; adherence interventions must be broadly based, rather than targeted to specific population subgroups; and counseling with a trusted clinician needs to be complemented by outreach interventions and removal of structural and organizational barriers. To achieve the adherence goals set by CMS, front-line clinicians, interdisciplinary teams, organizational leaders, and policymakers will need to coordinate efforts in ways that exemplify the underlying principles of health care reform. PMID:23070491

  10. Nano-scale topography of bearing surface in advanced alumina/zirconia hip joint before and after severe exposure in water vapor environment.

    PubMed

    Pezzotti, Giuseppe; Saito, Takuma; Padeletti, Giuseppina; Cossari, Pierluigi; Yamamoto, Kengo

    2010-06-01

    The aim of this study was to perform a surface morphology assessment with nanometer scale resolution on femoral heads made of an advanced zirconia toughened alumina (ZTA) composite. Femoral heads were characterized to a degree of statistical accuracy in the as-received state and after exposures up to 100 h in severe vapor-moist environment. Surface screening was made using an atomic force microscope (AFM). Scanning was systematically repeated on portions of surface as large as several tens of micrometers, randomly selected on the head surface, to achieve sufficient statistical reliability without lowering the nanometer-scale spatial resolution of the roughness measurement. No significant difference was found in the recorded values of surface roughness after environmental exposure (at 134 degrees C, under 2 bar), which was always comparable to that of the as-received head. Surface roughness safely lay <10 nm after environmental exposures up to 100 h, which corresponded to an exposure time in vivo of several human lifetimes (i.e., according to an experimentally derived thermal activation energy). In addition, the roughness results were significantly (about one order of magnitude) lower as compared to those recorded on femoral heads made of monolithic zirconia tested under the same conditions. PMID:20058275

  11. Large Scale Laser Crystallization of Solution-based Alumina-doped Zinc Oxide (AZO) Nanoinks for Highly Transparent Conductive Electrode

    PubMed Central

    Nian, Qiong; Callahan, Michael; Saei, Mojib; Look, David; Efstathiadis, Harry; Bailey, John; Cheng, Gary J.

    2015-01-01

    A new method combining aqueous solution printing with UV Laser crystallization (UVLC) and post annealing is developed to deposit highly transparent and conductive Aluminum doped Zinc Oxide (AZO) films. This technique is able to rapidly produce large area AZO films with better structural and optoelectronic properties than most high vacuum deposition, suggesting a potential large-scale manufacturing technique. The optoelectronic performance improvement attributes to UVLC and forming gas annealing (FMG) induced grain boundary density decrease and electron traps passivation at grain boundaries. The physical model and computational simulation developed in this work could be applied to thermal treatment of many other metal oxide films. PMID:26515670

  12. Large Scale Laser Crystallization of Solution-based Alumina-doped Zinc Oxide (AZO) Nanoinks for Highly Transparent Conductive Electrode.

    PubMed

    Nian, Qiong; Callahan, Michael; Saei, Mojib; Look, David; Efstathiadis, Harry; Bailey, John; Cheng, Gary J

    2015-01-01

    A new method combining aqueous solution printing with UV Laser crystallization (UVLC) and post annealing is developed to deposit highly transparent and conductive Aluminum doped Zinc Oxide (AZO) films. This technique is able to rapidly produce large area AZO films with better structural and optoelectronic properties than most high vacuum deposition, suggesting a potential large-scale manufacturing technique. The optoelectronic performance improvement attributes to UVLC and forming gas annealing (FMG) induced grain boundary density decrease and electron traps passivation at grain boundaries. The physical model and computational simulation developed in this work could be applied to thermal treatment of many other metal oxide films. PMID:26515670

  13. Large Scale Laser Crystallization of Solution-based Alumina-doped Zinc Oxide (AZO) Nanoinks for Highly Transparent Conductive Electrode

    NASA Astrophysics Data System (ADS)

    Nian, Qiong; Callahan, Michael; Saei, Mojib; Look, David; Efstathiadis, Harry; Bailey, John; Cheng, Gary J.

    2015-10-01

    A new method combining aqueous solution printing with UV Laser crystallization (UVLC) and post annealing is developed to deposit highly transparent and conductive Aluminum doped Zinc Oxide (AZO) films. This technique is able to rapidly produce large area AZO films with better structural and optoelectronic properties than most high vacuum deposition, suggesting a potential large-scale manufacturing technique. The optoelectronic performance improvement attributes to UVLC and forming gas annealing (FMG) induced grain boundary density decrease and electron traps passivation at grain boundaries. The physical model and computational simulation developed in this work could be applied to thermal treatment of many other metal oxide films.

  14. Bauxite and alumina

    USGS Publications Warehouse

    Bray, E.L.

    2009-01-01

    The article provides information on bauxite and alumina mining. U.S. states like Alabama, Arkansas and Georgia produced small amounts of bauxite and bauxitic clays for nonmetallurgical uses. Total metallurgical-grade bauxite imports in 2008 is cited. The leading suppliers of bauxite to the U.S. are Jamaica, Guinea and Brazil. The estimated domestic production of alumina in 2008 is mentioned. It also discusses consumption and prices of both bauxite and alumina.

  15. Porous Alumina Films with Width-Controllable Alumina Stripes

    PubMed Central

    2010-01-01

    Porous alumina films had been fabricated by anodizing from aluminum films after an electropolishing procedure. Alumina stripes without pores can be distinguished on the surface of the porous alumina films. The width of the alumina stripes increases proportionally with the anodizing voltage. And the pores tend to be initiated close to the alumina stripes. These phenomena can be ascribed to the electric field distribution in the alumina barrier layer caused by the geometric structure of the aluminum surface. PMID:21170406

  16. Porous Alumina Films with Width-Controllable Alumina Stripes.

    PubMed

    Huang, Kai; Huang, Shi-Ming; Pu, Lin; Shi, Yi; Wu, Zhi-Ming; Ji, Li; Kang, Jun-Yong

    2010-01-01

    Porous alumina films had been fabricated by anodizing from aluminum films after an electropolishing procedure. Alumina stripes without pores can be distinguished on the surface of the porous alumina films. The width of the alumina stripes increases proportionally with the anodizing voltage. And the pores tend to be initiated close to the alumina stripes. These phenomena can be ascribed to the electric field distribution in the alumina barrier layer caused by the geometric structure of the aluminum surface. PMID:21170406

  17. Porous Alumina Films with Width-Controllable Alumina Stripes

    NASA Astrophysics Data System (ADS)

    Huang, Kai; Huang, Shi-Ming; Pu, Lin; Shi, Yi; Wu, Zhi-Ming; Ji, Li; Kang, Jun-Yong

    2010-12-01

    Porous alumina films had been fabricated by anodizing from aluminum films after an electropolishing procedure. Alumina stripes without pores can be distinguished on the surface of the porous alumina films. The width of the alumina stripes increases proportionally with the anodizing voltage. And the pores tend to be initiated close to the alumina stripes. These phenomena can be ascribed to the electric field distribution in the alumina barrier layer caused by the geometric structure of the aluminum surface.

  18. Microporous alumina ceramic membranes

    DOEpatents

    Anderson, M.A.; Guangyao Sheng.

    1993-05-04

    Several methods are disclosed for the preparation microporous alumina ceramic membranes. For the first time, porous alumina membranes are made which have mean pore sizes less than 100 Angstroms and substantially no pores larger than that size. The methods are based on improved sol-gel techniques.

  19. Microporous alumina ceramic membranes

    DOEpatents

    Anderson, Marc A.; Sheng, Guangyao

    1993-01-01

    Several methods are disclosed for the preparation microporous alumina ceramic membranes. For the first time, porous alumina membranes are made which have mean pore sizes less than 100 Angstroms and substantially no pores larger than that size. The methods are based on improved sol-gel techniques.

  20. HIV Medication Adherence

    MedlinePlus

    HIV Treatment HIV Medication Adherence (Last updated 3/1/2016; last reviewed 3/1/2016) Key Points Medication adherence means sticking ... exactly as prescribed. Why is adherence to an HIV regimen important? Adherence to an HIV regimen gives ...

  1. Optimizing adherence to antiretroviral therapy

    PubMed Central

    Sahay, Seema; Reddy, K. Srikanth; Dhayarkar, Sampada

    2011-01-01

    HIV has now become a manageable chronic disease. However, the treatment outcomes may get hampered by suboptimal adherence to ART. Adherence optimization is a concrete reality in the wake of ‘universal access’ and it is imperative to learn lessons from various studies and programmes. This review examines current literature on ART scale up, treatment outcomes of the large scale programmes and the role of adherence therein. Social, behavioural, biological and programme related factors arise in the context of ART adherence optimization. While emphasis is laid on adherence, retention of patients under the care umbrella emerges as a major challenge. An in-depth understanding of patients’ health seeking behaviour and health care delivery system may be useful in improving adherence and retention of patients in care continuum and programme. A theoretical framework to address the barriers and facilitators has been articulated to identify problematic areas in order to intervene with specific strategies. Empirically tested objective adherence measurement tools and approaches to assess adherence in clinical/ programme settings are required. Strengthening of ART programmes would include appropriate policies for manpower and task sharing, integrating traditional health sector, innovations in counselling and community support. Implications for the use of theoretical model to guide research, clinical practice, community involvement and policy as part of a human rights approach to HIV disease is suggested. PMID:22310817

  2. Deposition of thick and adherent Teflon-like coating on industrial scale stainless steel shell using pulsed dc and RF PECVD

    NASA Astrophysics Data System (ADS)

    Satyaprasad, A.; Nema, S. K.; Sinha, N. K.; Raj, Baldev

    2010-04-01

    A unique combination of pulsed dc and radio frequency (RF) discharge deposition was used to deposit thick (˜5 μm) and adherent (2-4 MPa) Teflon-like coatings on a stainless steel (SS) shell of 2 m diameter size, through plasma enhanced chemical vapor deposition (PECVD). The details of deposition on such a big industrial scale component are reported for the first time. In this method, highly adherent thin interface layers were grown on SS shell that was electrically grounded, using pulsed dc discharge, followed by RF discharge deposition to build up the required coating thickness. The fluorocarbon precursor molecules, required for the deposition of Teflon-like coating, are generated indigenously by pyrolyzing the Teflon powder. The deposited coating was studied for its chemical bond state, surface roughness (Ra), morphology, thickness, and adhesive strength. These studies were carried out by using XPS, AFM, SEM, etc. The adhesive strength of the coating was measured by pin-pull test as per ASTM D4541 standard test. The coatings deposited with pulsed dc discharge were observed to have higher adhesive strength when compared with those deposited with RF discharge.

  3. Psychosocial Predictors of Non-Adherence and Treatment Failure in a Large Scale Multi-National Trial of Antiretroviral Therapy for HIV: Data from the ACTG A5175/PEARLS Trial

    PubMed Central

    Safren, Steven A.; Biello, Katie B.; Smeaton, Laura; Mimiaga, Matthew J.; Walawander, Ann; Lama, Javier R.; Rana, Aadia; Nyirenda, Mulinda; Kayoyo, Virginia M.; Samaneka, Wadzanai; Joglekar, Anjali; Celentano, David; Martinez, Ana; Remmert, Jocelyn E.; Nair, Aspara; Lalloo, Umesh G.; Kumarasamy, Nagalingeswaran; Hakim, James; Campbell, Thomas B.

    2014-01-01

    Background PEARLS, a large scale trial of antiretroviral therapy (ART) for HIV (n = 1,571, 9 countries, 4 continents), found that a once-daily protease inhibitor (PI) based regimen (ATV+DDI+FTC), but not a once-daily non-nucleoside reverse transcriptase inhibitor/nucleoside reverse transcriptase inhibitor (NNRTI/NRTI) regimen (EFV+FTC/TDF), had inferior efficacy compared to a standard of care twice-daily NNRTI/NRTI regimen (EFV+3TC/ZDV). The present study examined non-adherence in PEARLS. Methods Outcomes: non-adherence assessed by pill count and by self-report, and time to treatment failure. Longitudinal predictors: regimen, quality of life (general health perceptions  =  QOL-health, mental health  =  QOL-mental health), social support, substance use, binge drinking, and sexual behaviors. “Life-Steps” adherence counseling was provided. Results In both pill-count and self-report multivariable models, both once-a-day regimens had lower levels of non-adherence than the twice-a-day standard of care regimen; although these associations attenuated with time in the self-report model. In both multivariable models, hard-drug use was associated with non-adherence, living in Africa and better QOL-health were associated with less non-adherence. According to pill-count, unprotected sex was associated with non-adherence. According to self-report, soft-drug use was associated with non-adherence and living in Asia was associated with less non-adherence. Both pill-count (HR = 1.55, 95% CI: 1.15, 2.09, p<.01) and self-report (HR = 1.13, 95% CI: 1.08, 1.13, p<.01) non-adherence were significant predictors of treatment failure over 72 weeks. In multivariable models (including pill-count or self-report nonadherence), worse QOL-health, age group (younger), and region were also significant predictors of treatment failure. Conclusion In the context of a large, multi-national, multi-continent, clinical trial there were variations in adherence over time, with more

  4. Reuse of activated alumina

    SciTech Connect

    Hobensack, J.E.

    1991-12-31

    Activated alumina is used as a trapping media to remove trace quantities of UF{sub 6} from process vent streams. The current uranium recovery method employs concentrated nitric acid which destroys the alumina pellets and forms a sludge which is a storage and disposal problem. A recently developed technique using a distilled water rinse followed by three dilute acid rinses removes on average 97% of the uranium, and leaves the pellets intact with crush strength and surface area values comparable with new material. Trapping tests confirm the effectiveness of the recycled alumina as UF{sub 6} trapping media.

  5. [Treatment adherence: a key element].

    PubMed

    Bastida, Guillermo; Sánchez Montes, Cristina; Aguas, Mariam

    2011-12-01

    A substantial percentage of patients fail to follow health professionals' recommendations, which affects the management of chronic diseases, reducing the effectiveness of therapeutic interventions and increasing the costs of the disease. Lack of adherence is a multidimensional phenomenon and is influenced by numerous factors that should be identified. A multiplicity of measures is available to improve adherence, such as simplifying treatment administration, but none of these measures is effective when used alone. One way of tackling lack of adherence is by identifying patients' barriers to medication and involving them in decision making. Ulcerative colitis (UC) poses a risk for lack of treatment adherence. In this disease, poor adherence correlates with poor disease control (drug effectiveness) and with higher costs. As in other chronic diseases, the causes associated with poor adherence are multiple, including psychosocial factors, the physician-patient relationship and patients' prejudices toward medication. A single dose of aminosalycylates (5-ASA) should be recommended, as this dose is as safe and effective as other regimens. However, by itself, this recommendation does not seem to improve adherence. Identifying the scale of the problem and developing strategies to involve the patient in decision making is crucial to improve treatment adherence. PMID:25443221

  6. Alumina from oil shale

    SciTech Connect

    Smith, J.W.

    1980-01-01

    Dawsonite-bearing oil shale of Colorado's Green River Formation offers a unique and vast (6.5 billion tons of Al/sub 2/O/sub 3/) resource of easily extractable alumina. The processing methods required by the thermal reactions of dawsonite and its oil-shale carrier also require production of shale oil, soda ash, and nahcolite as marketable coproducts. These production methods are presented. The alumina production process is contrasted with the Bayer process to describe technical advantages of extraction of alumina from oil shale which may offset the problems associated with processing a relatively lean ore. While alumina production from oil shale requires development of new technology, the technical problems appear solvable. Only the political problems arising from the now onerous and completely unnecessary Federal oil-shale withdrawal appear less solvable.

  7. Bauxite and alumina

    USGS Publications Warehouse

    Bray, E.L.

    2011-01-01

    The article discusses the latest developments in the bauxite and alumina industry, particularly in the U.S., as of June 2011. It claims that the U.S. mainly relies on imports for its bauxite consumption. Several states, including Alabama, Arkansas and Georgia, however, produce small amounts of bauxite and bauxitic clays for nonmetallurgical purposes. The major exporters of alumina to the U.S. include Australia, Brazil and Jamaica.

  8. Alumina fiber strength improvement

    NASA Technical Reports Server (NTRS)

    Pepper, R. T.; Nelson, D. C.

    1982-01-01

    The effective fiber strength of alumina fibers in an aluminum composite was increased to 173,000 psi. A high temperature heat treatment, combined with a glassy carbon surface coating, was used to prevent degradation and improve fiber tensile strength. Attempts to achieve chemical strengthening of the alumina fiber by chromium oxide and boron oxide coatings proved unsuccessful. A major problem encountered on the program was the low and inconsistent strength of the Dupont Fiber FP used for the investigation.

  9. Large-Scale Production of High-Quality Helper-Dependent Adenoviral Vectors Using Adherent Cells in Cell Factories

    PubMed Central

    Suzuki, Masataka; Cela, Racel; Clarke, Christian; Bertin, Terry K.; Mouriño, Susana

    2010-01-01

    Abstract The most efficient and widely used system for generating helper-dependent adenoviral vectors (HDAds) is the Cre/loxP system developed by Graham and co-workers (Parks, R.J., Chen, L., Anton, M., Sankar, U., Rudnicki, M.A., and Graham, F.L. [1996]. Proc. Natl. Acad. Sci. U. S. A. 93, 13565–13570). Alternative systems have been developed for HDAd production, but all are limited by the technical complexity of a three-component vector production system for reproducibly generating large quantities of adenovirus with high infectivity and low helper virus (HV) contamination. Recently, these problems were addressed by Ng and co-workers (Palmer, D., and Ng, P. [2003]. Mol Ther. 8, 846–852), who developed an improved system that combines the use of a suspension-adapted producer cell line expressing high levels of Cre recombinase, a HV resistant to mutation, and a refined purification protocol. With this system, >1 × 1013 highly infectious vector particles are easily produced without vector genome rearrangements and having very low HV contamination levels. However, the Ng system incorporates a spinner flask culture system that involves considerable time, effort, and tissue culture medium to produce HDAds. We have an alternative system to obtain comparable quantities with equivalent quality to the spinner flask approach but requiring reduced labor and lower volumes of medium. This method utilizes a 10-chamber cell factory with adherent cells to produce high infectivity of HDAds with minimal HV contamination while improving yield and reducing technical complexity, effort, and medium requirements. This system is easily translatable to the production of clinical-grade HDAds for human trials. PMID:19719388

  10. Large pore alumina

    SciTech Connect

    Ternan, M. )

    1994-04-01

    Earlier the authors reported preparation conditions for an alumina material which contained large diameter macropores (0.1-100 [mu]). The preparation variable that caused the formation of the uncommonly large macropores was the large acid/alumina ratios which were very much greater than the ones used in the preparation of conventional porous aluminas. The alumina material had large BET surface areas (200 m[sup 2]/g) and small mercury porosimetry surface areas (1 m[sup 2]/g). This indicated that micropores (d[sub MIP]<2 nm) were present in the alumina, since they were large enough for nitrogen gas molecules to enter, but too small for mercury to enter. As a result they would be too small for significant diffusion rates of residuum molecules. In earlier work, the calcining temperature was fixed at 500[degrees]C. In the current work, variations in both calcining temperature and calcining time were used in an attempt to convert some of the micropores into mesopores. 12 refs., 2 figs., 1 tab.

  11. Medication adherence to oral anticancer drugs: systematic review.

    PubMed

    Huang, Wen-Chuan; Chen, Chung-Yu; Lin, Shun-Jin; Chang, Chao-Sung

    2016-04-01

    Many studies have demonstrated that non-adherence to oral anticancer drugs (OACDs) has challenged treatment efficacy. Otherwise, few validated tools exist to measure patients' adherence to medication regimen in clinical practice. To synthesize previous studies on adherence by cancer patients taking OACDs, especially in targeted therapy, a systematic search of several electronic databases was conducted. We analyzed existing scales' contents for various cancer patients and outcomes of studies assessing adherence. However, a well-validated scale designed particularly for OACD adherence is still lacking. Most adherence scales used in the studies reviewed contain items focused on measuring patients' medication-taking behavior more than their barriers to medication compliance and beliefs. However, non-adherence to OACDs is a complex phenomenon, and drug-taking barriers and patient beliefs significantly affect patients' non-adherence. To understand the key drivers and predisposing factors for non-adherence, we need to develop a well-validated, multidimensional scale. PMID:26935964

  12. Screen-Cage Ion Plating Of Silver On Polycrystalline Alumina

    NASA Technical Reports Server (NTRS)

    Spalvins, Talivaldis; Sliney, Harold E.; Deadmore, Daniel L.

    1995-01-01

    Screen-cage ion plating (SCIP) cost-effective technique offering high throwing power for deposition of adherent metal films on ceramic substrates. Applies silver films to complexly shaped substrates of polycrystalline alumina. Silver adheres tenaciously and reduces friction. SCIP holds promise for applying lubricating soft metallic films to high-temperature ceramic components of advanced combustion engines. Other potential uses include coating substrates with metal for protection against corrosion, depositing electrical conductors on dielectric substrates, making optically reflective or electrically or thermally conductive surface layers, and applying decorative metal coats to ceramic trophies or sculptures.

  13. Alumina Technology Roadmap

    SciTech Connect

    none,

    2002-02-01

    The Alumina Technology Roadmap outlines a comprehensive long-term research and development plan that defines the industry's collective future and establishes a clear pathway forward. It emphasizes twelve high-priority R&D areas deemed most significant in addressing the strategic goals.

  14. Bauxite and alumina

    USGS Publications Warehouse

    Bray, E.L.

    2010-01-01

    The article reports on the global market performance of bauxite and alumina in 2009 and presents an outlook for their 2010 performance. There were only several U.S. states that could produce bauxite and bauxitic clays including Georgia, Arkansas, and Alabama. The prices for imported refractory-grade calcined bauxite ranged between 426 U.S. dollars and 554 dollars per ton.

  15. Prediction of alumina penetration

    SciTech Connect

    Mandell, D A

    1993-02-01

    The MESA hydrocode was used to predict two-dimensional tests of L/D 10 and L/D 15 tungsten rods impacting AD 90 alumina with a steel backing. The residual penetration into the steel is the measured quantity in these experiments conducted at the Southwest Research Institute (SWR). The interface velocity as a function of time between an alumina target and a lithium fluoride window, impacted by an alumina disk at velocities between 544 m/s and 2329 m/s, was also predicted. These one-dimensional flyer plate experiments were conducted at Sandia National Laboratories using Coors AD 995 alumina. The material strength and fracture models are important in the prediction of ceramic experiments. The models used in these predictions are discussed. The penetrations in the two-dimensional tests were predicted to 11.4 percent or better. In five of the six experiments, the predicted penetration depth was deeper than the measured value. This trend is expected since the calculation is based on ideal conditions. The results show that good agreement between the 1-D flyer plate data and the MESA predictions exists at the lower impact velocities, but the maximum velocity is overpredicted as the flyer plate velocity increases. At a flyer plate velocity of 2329 m/s the code overpredicted the data by 12.3 percent.

  16. Solid Lubricant For Alumina

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Pepper, Stephen V.; Honecy, Frank S.

    1993-01-01

    Outer layer of silver lubricates, while intermediate layer of titanium ensures adhesion. Lubricating outer films of silver deposited on thin intermediate films of titanium on alumina substrates found to reduce sliding friction and wear. Films provide effective lubrication for ceramic seals, bearings, and other hot sliding components in advanced high-temperature engines.

  17. Alumina forming iron base superalloy

    SciTech Connect

    Yamamoto, Yukinori; Muralidharan, Govindarajan; Brady, Michael P.

    2014-08-26

    An austenitic stainless steel alloy, consists essentially of, in weight percent 2.5 to 4 Al; 25 to 35 Ni; 12 to 19 Cr; at least 1, up to 4 total of at least one element selected from the group consisting of Nb and Ta; 0.5 to 3 Ti; less than 0.5 V; 0.1 to 1 of at least on element selected from the group consisting of Zr and Hf; 0.03 to 0.2 C; 0.005 to 0.1 B; and base Fe. The weight percent Fe is greater than the weight percent Ni. The alloy forms an external continuous scale including alumina, and contains coherent precipitates of .gamma.'-Ni.sub.3Al, and a stable essentially single phase FCC austenitic matrix microstructure. The austenitic matrix is essentially delta-ferrite-free and essentially BCC-phase-free.

  18. The Association between Poor Antiretroviral Adherence and Unsafe Sex: Differences by Gender and Sexual Orientation and Implications for Scale-Up of Treatment as Prevention

    PubMed Central

    Remien, Robert H.; Dolezal, Curtis; Wagner, Glenn J.; Goggin, Kathy; Wilson, Ira B.; Gross, Robert; Rosen, Marc I.; Shen, Jie; Simoni, Jane M.; Golin, Carol E.; Arnsten, Julia H.; Bangsberg, David R.; Liu, Honghu

    2013-01-01

    Non-adherence to safer sex and non-adherence to ART can each have adverse health consequences for HIV-infected individuals and their sex partners, but little is known about the association of these behaviors with each other. This “dual risk” has potential negative public health consequences since non-adherence can lead to the development of resistant virus that can then be transmitted to sex partners. Among participants in the Multi-site Adherence Collaboration in HIV (MACH14) we examined, at study baseline, the association between the frequency of unprotected sex (assessed by self-report) and ART adherence (assessed by Medication Event Monitoring System, Aardex) among the sexually active participants in the five studies (N=459) that collected sexual risk behavior. The bivariate association between sexual risk behaviors and ART adherence was assessed by Pearson correlations; subsequently ANOVAs were used to evaluate the role of demographic characteristics, depression and substance use in explaining the “dual risk” outcome (sexual risk and non-adherence). Among participants who had been sexually active, more unprotected anal/vaginal sex was weakly associated with poorer ART adherence (r = −.12, p=0.01 for the overall sample). Further analysis showed this association was driven by the heterosexual men in the sample (r = −.29, p<0.001), and was significant only for this group, and not for gay/bisexual men or for women (heterosexual and homosexual). Neither substance use nor depression accounted for the association between sexual risk and ART adherence. HIV-infected heterosexual men who are having difficulty adhering to ART are also more likely to engage in risky sexual behaviors and therefore may benefit from counseling about these risk behaviors. We must identify procedures to screen for these risk behaviors and develop interventions, appropriately tailored to specific populations and identified risk factors, that can be integrated into routine clinical

  19. Deformation Behaviour of Coarse Grain Alumina under Shock Loading

    NASA Astrophysics Data System (ADS)

    Gupta, Satish

    2013-06-01

    To develop better understanding of the shock wave induced deformation behavior of coarse grain alumina ceramics, and for measurement of its Hugoniot Elastic Limit (HEL), in-situ and recovery gas gun experiments have been carried out on coarse grain alumina (grain size ~ 10 μm), prepared in the form of discs (>99.9% TMD) by pressure-less sintering of alpha alumina powder at 1583 K. The HEL value of 1.9 GPa has been determined from the kink in the pressure history recorded using piezoresistance gauge and also from the free surface velocity history of the sample shocked to 9 GPa. The nano-indentation measurements on the alumina samples shocked to 6.5 GPa showed hardness value 15% lower than 21.3 GPa for unshocked alumina, and strong Indentation Size Effect (ISE); the hardness value was still lower and the ISE was stronger for the sample shocked to 12 GPa. The XRD measurements showed reduced particle size and increased microstrains in the shocked alumina fragments. SEM, FESEM and TEM measurements on shock treated samples showed presence of grain localized micro- and nano-scale deformations, micro-cleavages, grain-boundary microcracks, extensive shear induced deformations, and localized micro-fractures, etc. These observations led to the development of a qualitative model for the damage initiation and its subsequent growth mechanisms in shocked alumina. The work performed in collaboration with K.D. Joshi of BARC and A.K. Mukhopadhyay of CGCRI.

  20. High Temperature Stability of Potassium Beta Alumina

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Kisor, A.; Ryan, M. A.

    1996-01-01

    None. From Objectives section: Evaluate the stability of potassium beta alumina under potassium AMTEC operating conditions. Evaluate the stability regime in which potassium beta alumina can be fabricated.

  1. Medication adherence among adult patients on hemodialysis.

    PubMed

    Alkatheri, Abdulmalik M; Alyousif, Sarah M; Alshabanah, Najla; Albekairy, Abdulkareem M; Alharbi, Shemylan; Alhejaili, Fayze F; Alsayyari, Abdullah A; Qandil, Abeer Ma; Qandil, Amjad M

    2014-07-01

    Medication adherence was assessed in 89 patients on hemodialysis (HD) at the King Abdul Aziz Medical City using an Arabic version of the Morisky Medication Adherence Scale (MASS-8). The results of the study revealed that 31.46% and 40.45% of the participants showed low and medium adherence, respectively, while 28.09% showed high medication adherence. Accordingly, 71.91% of the patients visiting the dialysis unit were considered medication non-adherent. While being of older age (P = 0.012), being married (P = 0.012) increased the level of adherence, being of medium level of education (P = 0.024) decreased adherence levels. On the other hand, gender, presence of a care-giver, number of members in the household and employment status seems to have no effect on the level of medication adherence. These results call upon the practitioners in HD units to develop intervention programs that can increase the level of medication adherence. PMID:24969185

  2. Alumina reduction cell

    SciTech Connect

    Tabereaux, A.T.; Gunnip, F.L.

    1987-06-16

    An alumina reduction cell is described having a cathode and an anode. The anode is formed of a carbonaceous paste and baked during operation of cell and the anode having rows of anode pins on opposing faces. The pins are positioned by passing the pins through openings in anode channels vertically stacked along the opposing faces of the anode. The lowermost row of anode pins carries current through the anode; the improvement positions the anode pins passing through along a line of constant current distribution in the anode.

  3. Bauxite Mining and Alumina Refining

    PubMed Central

    Frisch, Neale; Olney, David

    2014-01-01

    Objective: To describe bauxite mining and alumina refining processes and to outline the relevant physical, chemical, biological, ergonomic, and psychosocial health risks. Methods: Review article. Results: The most important risks relate to noise, ergonomics, trauma, and caustic soda splashes of the skin/eyes. Other risks of note relate to fatigue, heat, and solar ultraviolet and for some operations tropical diseases, venomous/dangerous animals, and remote locations. Exposures to bauxite dust, alumina dust, and caustic mist in contemporary best-practice bauxite mining and alumina refining operations have not been demonstrated to be associated with clinically significant decrements in lung function. Exposures to bauxite dust and alumina dust at such operations are also not associated with the incidence of cancer. Conclusions: A range of occupational health risks in bauxite mining and alumina refining require the maintenance of effective control measures. PMID:24806720

  4. Osseointegration of alumina bioceramic granules: A comparative experimental study

    NASA Astrophysics Data System (ADS)

    Rerikh, V. V.; Avetisyan, A. R.; Zaydman, A. M.; Anikin, K. A.; Bataev, V. A.; Nikulina, A. A.; Sadovoy, M. A.; Aronov, A. M.; Semantsova, E. S.

    2016-08-01

    To perform a comparative analysis of osseointegration of bioceramic alumina-based granules, hydroxyapatite-based granules, and deproteinized bone granules. The experiment was conducted on 52 adult male Kyoto-Wistar rats weighing 350 to 520 g. The animals were divided into five matched groups that differed only in the type of an implanted material. The granules were implanted in the lumbar vertebral bodies and in the distal right femur of each laboratory animal. Two months after surgery, the animals were euthanized, followed by tissue sampling for morphological studies. An examination of specimens from the groups with implanted alumina granules revealed the newly formed trabecular bone with remodeling signs. The bone tissue filled the intragranular space, tightly adhering to the granule surface. There was no connective tissue capsule on the border between bone tissue and alumina granules. Cylindrical bioceramic alumina-based granules with an open internal channel have a higher strength surpassing than that of analogs and the osseointegration ability close to that of hydroxyapatite and deproteinized bone granules.

  5. Branchy alumina nanotubes

    NASA Astrophysics Data System (ADS)

    Zou, Jianping; Pu, Lin; Bao, Ximao; Feng, Duan

    2002-02-01

    Branchy alumina nanotubes (bANTs) have been shown to exist in aluminum oxide. Electron-beam evaporated 400 nm Al film on Si substrate is stepwise anodized in dilute sulfuric acid under the constant dc voltage 40 V at 10.0 °C. This electrochemical-anodizing route resulted in the formation of individual bANTs. Transmission electron microscopy showed that the length of the bANTs was around 450 nm, and the inner diameter was around 10-20 nm. We deduced that the bANTs, the completely detached multibranchy cells of anodic porous alumina (APA) film, should be evolved from the stagnant cells of the APA mother film. The bANTs may be used as templates in fabrication of individual branchy nanoscale cables, jacks, and heterojunctions. The proposed formation mechanisms of the bANTs and the stagnant cells should give some insights into the long-standing problem of APA film, i.e., the self-ordering mechanism of the cells arrangement in porous anodization of aluminum.

  6. Production and characterization of alumina-titania biocomposite

    NASA Astrophysics Data System (ADS)

    Cetiner, B. N.; Erkmen, Z. E.

    2015-03-01

    Alumina is a biomaterial of choice for more than 20 years due to its high hardness accompanied by low friction, wear and inertness to in vivo environment. It has been reported that titanium oxidized to the rutile phase is bioactive. This is a property discovered for certain ceramics such as Bioglass and sintered hydroxylapatite (HA). But the combination of alumina and titania forming tialite (Aluminium titanate-50 mol % Al2O3 and 50 mol % TiO2) is a new challenge. In this work we made firstly the beneficiation of the Seydişehir alumina by leaching it in the acidic solution "the Aqua Regia" followed by preparation of batches containing 2,5 wt %, 3,5 wt % and 4,5 wt % of MgO as the sintering aid, 1 wt % of SiO2 and the balance; the alumina and titania powder mixture (1:1 mole). After sintering these batches at 1600°C for about 12 h, their mechanical properties (the compression and hardness testings) and phase ratios (the XRD analysis) were analyzed and compared with the control group containing the laboratory scale alumina instead of the Seydişehir alumina. Following the characterization (the SEM and the EDS analysis) of the substrate material, the comparison of two different materials was carried out.

  7. Gelcasting Polycrystalline Alumina

    SciTech Connect

    Janney, M.A.; Zuk, K.J.; Wei, G.C.

    2000-01-01

    OSRAM SYLVANIA INC. is a major U.S. manufacturer of high-intensity lighting. Among its products is the Lumalux TM line of high-pressure sodium vapor arc lamps, which are used for industrial, highway, and street lighting. The key to the performance of these lamps is the polycrystalline alumina (PCA) tube that is used to contain the plasma that is formed in the electric arc. That plasma consists of ionized sodium, mercury, and xenon vapors. The key attributes of the PCA tubes are their transparency ({approximately}97% total transmittance in the visible), their refractoriness (inner wall temperature can reach l2OOC), and their chemical resistance (sodium and mercury vapor are extremely corrosive). The current efficiency of the lamps is very high, up to 100 initial lumens per watt. (Compare incandescent lamps 10-20 lumens per watt, fluorescent lamps 25-90 lumens per watt.)

  8. Enigmatic Moisture Effects on Al2O3 Scale and TBC Adhesion

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2008-01-01

    Alumina scale adhesion to high temperature alloys is known to be affected primarily by sulfur segregation and reactive element additions. However adherent scales can become partially compromised by excessive strain energy and cyclic cracking. With time, exposure of such scales to moisture can lead to spontaneous interfacial decohesion, occurring while the samples are maintained at ambient conditions. Examples of this Moisture-Induced Delayed Spallation (MIDS) are presented for NiCrAl and single crystal superalloys, becoming more severe with sulfur level and cyclic exposure conditions. Similarly, delayed failure or Desk Top Spallation (DTS) results are reviewed for TBC s, culminating in the water drop failure test. Both phenomena are discussed in terms of moisture effects on bulk alumina and bulk aluminides. A mechanism is proposed based on hydrogen embrittlement and is supported by a cathodic hydrogen charging experiment. Hydroxylation of aluminum from the alloy interface appears to be the relevant basic reaction.

  9. Enigmatic Moisture Effects on Al2O3 Scale and TBC Adhesion

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2008-01-01

    Alumina scale adhesion to high temperature alloys is known to be affected primarily by sulfur segregation and reactive element additions. However, adherent scales can become partially compromised by excessive strain energy and cyclic cracking. With time, exposure of such scales to moisture can lead to spontaneous interfacial decohesion, occurring while the samples are maintained at ambient conditions. Examples of this Moisture-Induced Delayed Spallation (MIDS) are presented for NiCrAl and single crystal superalloys, becoming more severe with sulfur level and cyclic exposure conditions. Similarly, delayed failure or Desk Top Spallation (DTS) results are reviewed for thermal barrier coatings (TBCs), culminating in the water drop failure test. Both phenomena are discussed in terms of moisture effects on bulk alumina and bulk aluminides. A mechanism is proposed based on hydrogen embrittlement and is supported by a cathodic hydrogen charging experiment. Hydroxylation of aluminum from the alloy interface appears to be the relevant basic reaction.

  10. Alumina-forming Austenitic Alloys for Advanced Recuperators

    SciTech Connect

    Pint, Bruce A; Shingledecker, John P; Brady, Michael P; Maziasz, Philip J

    2007-01-01

    Materials selection for thin-walled recuperators has been extensively investigated over the past decade. In the latest generation of recuperated turbine engines, type 347 stainless steel has been replaced by higher alloyed steels and Ni-base chromia-forming alloys. However, high (linear) rates of chromia evaporation in exhaust gas fundamentally limits the oxidation lifetime of these chromia-forming alloys. One solution is to use alumina-forming alloys that are more resistant to this environment. The lower scale growth kinetics and resistance to evaporation in the presence of water vapor suggests an order of magnitude increase in lifetime for alumina-forming alloys. A significant problem with this strategy was the large drop in creep strength with the addition of sufficient Al to form an external alumina scale. However, new Fe-base austenitic compositions have been developed with sufficient strength for this application above 700 C.

  11. [Strategies for measuring medication adherence in patients with schizophrenia].

    PubMed

    Wang, Yunfang; Huang, Zhiping; Xu, Dong; Gong, Wenjie; Tang, Yuan; Xiao, Shuiyuan

    2016-02-01

    Long-term therapy should be administrated for patients with schizophrenia and the medication adherence is very important for the prognosis and outcome in these patients. In this study, we screened the literatures from various databases in accordance with our search criteria. A total of 11 literatures with the results of reliability and validity regarding the measurement of schizophrenia medication adherence were enrolled in our analysis. Based on the measurements, they were classified into subjective methods and objective ones. The objective methods include blood plasma and urine concentrations, pharmacy records, pill counts and Medication Event Monitoring System. The subjective methods include Drug Attitude Inventory, Rating of Medication Influences Scale, Brief Evaluation of Medication Influences and Beliefs, the Brief Adherence Rating Scale, Medication Adherence Rating Scale, and Morisky scales. In general, single method for measuring medication adherence in patients with schizophrenia is limited. We recommend researchers to use 2 or more methods when measuring the medication adherence in patients with schizophrenia. PMID:26932222

  12. Alumina-Reinforced Zirconia Composites

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Bansal, Narottam P.

    2003-01-01

    Alumina-reinforced zirconia composites, used as electrolyte materials for solid oxide fuel cells, were fabricated by hot pressing 10 mol percent yttria-stabilized zirconia (10-YSZ) reinforced with two different forms of alumina particulates and platelets each containing 0 to 30 mol percent alumina. Major mechanical and physical properties of both particulate and platelet composites including flexure strength, fracture toughness, slow crack growth, elastic modulus, density, Vickers microhardness, thermal conductivity, and microstructures were determined as a function of alumina content either at 25 C or at both 25 and 1000 C. Flexure strength and fracture toughness at 1000 C were maximized with 30 particulate and 30 mol percent platelet composites, respectively, while resistance to slow crack growth at 1000 C in air was greater for 30 mol percent platelet composite than for 30 mol percent particulate composites.

  13. Gelcast zirconia-alumina composites

    SciTech Connect

    Omatete, O.O.; Bleier, A.; Westmoreland, C.G.; Young, A.C.

    1991-01-01

    Near net-shaped parts of zirconia-alumina composites have been successfully formed by gelcasting, a technique which utilizes in situ polymerization of acrylamide monomers. The high solids loading required for gelcasting ({approximately}50 vol %) was obtained by controlling the pH-dependent stability of the aqueous zirconia-alumina suspensions. A strong correspondence was found among the surface charges on the particles, colloidal stability, and the maximum solids loading. 14 refs., 3 figs., 2 tabs.

  14. Adherence to Antihypertensive Medications in Iranian Patients

    PubMed Central

    Behnood-Rod, Azin; Rabbanifar, Omid; Pourzargar, Pirouz; Rai, Alireza; Saadat, Zahra; Saadat, Habibollah; Moharamzad, Yashar; Morisky, Donald E.

    2016-01-01

    Introduction. Appropriate adherence to medication is still a challenging issue for hypertensive patients. We determined adherence to antihypertensive(s) and its associated factors among 280 Iranian patients. Methods. They were recruited consecutively from private and university health centers and pharmacies in four cities. The validated Persian version of the 8-item Morisky Medication Adherence Scale (MMAS-8) was administered to measure adherence. Results. Mean (±SD) overall MMAS-8 score was 5.75 (±1.88). About half of the sample (139 cases, 49.6%) showed low adherence (MMAS-8 score < 6). There was a negative linear association between the MMAS-8 score and systolic BP (r = −0.231, P < 0.001) as well as diastolic BP (r = −0.280, P < 0.001). In linear regression model, overweight/obesity (B = −0.52, P = 0.02), previous history of admission to emergency services due to hypertensive crisis (B = −0.79, P = 0.001), and getting medication directly from drugstore without refill prescription in hand (B = −0.51, P = 0.04) were factors recognized to have statistically significant association with the MMAS-8 score. Conclusion. Antihypertensive adherence was unsatisfactory. We suggest that health care providers pay special attention and make use of the aforementioned findings in their routine visits of hypertensive patients to recognize those who are vulnerable to poor adherence. PMID:27069676

  15. Adherence to Antihypertensive Medications in Iranian Patients.

    PubMed

    Behnood-Rod, Azin; Rabbanifar, Omid; Pourzargar, Pirouz; Rai, Alireza; Saadat, Zahra; Saadat, Habibollah; Moharamzad, Yashar; Morisky, Donald E

    2016-01-01

    Introduction. Appropriate adherence to medication is still a challenging issue for hypertensive patients. We determined adherence to antihypertensive(s) and its associated factors among 280 Iranian patients. Methods. They were recruited consecutively from private and university health centers and pharmacies in four cities. The validated Persian version of the 8-item Morisky Medication Adherence Scale (MMAS-8) was administered to measure adherence. Results. Mean (±SD) overall MMAS-8 score was 5.75 (±1.88). About half of the sample (139 cases, 49.6%) showed low adherence (MMAS-8 score < 6). There was a negative linear association between the MMAS-8 score and systolic BP (r = -0.231, P < 0.001) as well as diastolic BP (r = -0.280, P < 0.001). In linear regression model, overweight/obesity (B = -0.52, P = 0.02), previous history of admission to emergency services due to hypertensive crisis (B = -0.79, P = 0.001), and getting medication directly from drugstore without refill prescription in hand (B = -0.51, P = 0.04) were factors recognized to have statistically significant association with the MMAS-8 score. Conclusion. Antihypertensive adherence was unsatisfactory. We suggest that health care providers pay special attention and make use of the aforementioned findings in their routine visits of hypertensive patients to recognize those who are vulnerable to poor adherence. PMID:27069676

  16. Evaluation of medication adherence in Lebanese hypertensive patients.

    PubMed

    Yassine, Mohammad; Al-Hajje, Amal; Awada, Sanaa; Rachidi, Samar; Zein, Salam; Bawab, Wafa; Bou Zeid, Mayssam; El Hajj, Maya; Salameh, Pascale

    2016-09-01

    Controlling hypertension is essential in cardiovascular diseases. Poor medication adherence is associated with poor disease outcomes, waste of healthcare resources, and contributes to reduced blood pressure control. This study evaluates treatment adherence to antihypertensive therapy in Lebanese hypertensive patients by estimating the proportion of adherent hypertensive patients using a validated tool and investigates what factors predict this behavior. A questionnaire-based cross-sectional study was conducted on a random sample of 210 hypertensive outpatients selected from clinics located in tertiary-care hospitals and from private cardiology clinics located in Beirut. Adherence level was measured using a validated 8-item Modified Morisky Medication Adherence Scale (MMMAS). Among 210 patients, 50.5% showed high adherence, 27.1% medium adherence, and 22.4% low adherence to medication. Mean MMMAS score was 6.59±2.0. In bivariate analyses, having controlled blood pressure (p=0.003) and taking a combination drug (p=0.023) were predictors of high adherence. Forgetfulness (p<0.01), complicated drug regimen (p=0.001), and side effects (p=0.006) were predictors of low adherence after multiple liner regression. Logistic regression results showed that calcium channel blockers (p=0.030) were associated with increased adherence levels. In conclusion, developing multidisciplinary intervention programs to address the factors identified, in addition to educational strategies targeting healthcare providers, are necessary to enhance patient adherence. PMID:26232704

  17. Large-scale enrichment of mobilized CD34+ peripheral blood hematopoietic progenitors by removal of nylon wool-adherent mature cells.

    PubMed

    Di Nicola, M; Siena, S; Bregni, M; Ravagnani, F; Vitello, F; Belli, N; Dodero, A; Magni, M; Bonadonna, G; Gianni, A M

    1994-12-01

    With the aim of facilitating the ex vivo manipulation of peripheral blood hematopoietic progenitors (CPCs = circulating progenitor cells) collected by leukapheresis, we removed polymorphonuclear cells and monocytes that naturally adhere to nylon wool fibers. Leukapheresed cells harvested at the time of hematopoietic recovery after cancer therapy with high-dose cyclophosphamide plus hematopoietic growth factors were incubated with nylon wool fibers for 1 h at 37 degrees C. Evaluation of the cells non-adherent to the nylon wool in all experiments (n = 14) showed that the median recovery of nucleated cells and CPCs detected as CD34+ cells, CFU-GM and BFU-E was 16.4% (range 4.8%-34.0%), 60.0% (range 30.8-80.8%), 60.9% (range 33.4-74.5%) and 65.5% (range 30.8-69.2%), respectively. Therefore exposure to the nylon wool determined a selective removal of mature cells and a complementary enrichment of CPCs. The wide range of results depended on the significantly different cell compositions of the unmanipulated leukaphereses. The latter from patients receiving rhG-CSF (n = 10) comprised a median of 88.5% (range 77.8-93.8%) and 11.5% (range 6.2-22.2%) polymorphonuclear and mononuclear cells, respectively. In contrast, leukaphereses from patients receiving rhGM-CSF or PIXY321 (n = 4) comprised a median of 71.1% (range 55.4-85.0%) and 28.9% (range 15.0-44.6%) polymorphonuclear and mononuclear cells, respectively.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7536068

  18. Influence of Alumina Reaction Tube Impurities on the Oxidation of Chemically-Vapor-Deposited Silicon Carbide

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth

    1995-01-01

    Pure coupons of chemically vapor deposited (CVD) SiC were oxidized for 100 h in dry flowing oxygen at 1300 C. The oxidation kinetics were monitored using thermogravimetry (TGA). The experiments were first performed using high-purity alumina reaction tubes. The experiments were then repeated using fused quartz reaction tubes. Differences in oxidation kinetics, scale composition, and scale morphology were observed. These differences were attributed to impurities in the alumina tubes. Investigators interested in high-temperature oxidation of silica formers should be aware that high-purity alumina can have significant effects on experiment results.

  19. Gelcasting polycrystalline alumina

    SciTech Connect

    Janney, M.A.

    1997-04-01

    This work is being done as part of a CRADA with Osram-Sylvania, Inc. (OSI) OSI is a major U.S. manufacturer of high-intensity lighting. Among its products is the Lumalux{reg_sign} line of high-pressure sodium vapor arc lamps, which are used for industrial, highway, and street lighting. The key to the performance of these lamps is the polycrystalline alumina (PCA) tube that is used to contain the plasma that is formed in the electric arc. That plasma consists of ionized sodium, mercury, and xenon vapors. The key attributes of the PCA tubes are their transparency (95% total transmittance in the visible region), their refractoriness (inner wall temperature can reach 1400{degrees}C), and their chemical resistance (sodium and mercury vapor are extremely corrosive). The current efficiency of the lamps is very high, on the order of several hundred lumens / watt. (Compare - incandescent lamps -13 lumens/watt fluorescent lamps -30 lumens/watt.) Osram-Sylvania would like to explore using gelcasting to form PCA tubes for Lumalux{reg_sign} lamps, and eventually for metal halide lamps (known as quartz-halogen lamps). Osram-Sylvania, Inc. currently manufactures PCA tubes by isostatic pressing. This process works well for the shapes that they presently use. However, there are several types of tubes that are either difficult or impossible to make by isostatic pressing. It is the desire to make these new shapes and sizes of tubes that has prompted Osram-Sylvania`s interest in gelcasting. The purpose of the CRADA is to determine the feasibility of making PCA items having sufficient optical quality that they are useful in lighting applications using gelcasting.

  20. Enhancing adherence through education.

    PubMed

    Smrtka, Jennifer; Caon, Christina; Saunders, Carol; Becker, Brenda L; Baxter, Nancy

    2010-10-01

    The treatment of multiple sclerosis (MS) has advanced greatly since the introduction of disease-modifying therapies (DMTs) in the early 1990s. Although the DMTs have exhibited significant efficacy in relapsing-remitting MS and other forms of the disease, the degree of benefit depends heavily on patient adherence to recommended regimens. This article addresses some of the most pressing areas of unmet need in educating advanced-practice nurses, neurologists, patients, and support care partners regarding strategies that can overcome obstacles to adherence. The observations presented here are based on clinical experience with real-life cognitive, psychosocial, and cultural impediments to adherence. The article also explores the ways in which adherence may be affected by emerging therapies for MS (such as oral agents) as well as the educational needs that will arise with the further evolution of MS care. PMID:21049830

  1. Adherence to Insulin Therapy.

    PubMed

    Sarbacker, G Blair; Urteaga, Elizabeth M

    2016-08-01

    IN BRIEF Six million people with diabetes use insulin either alone or in combination with an oral medication. Many barriers exist that lead to poor adherence with insulin. However, there is an underwhelming amount of data on interventions to address these barriers and improve insulin adherence. Until pharmacological advancements create easier, more acceptable insulin regimens, it is imperative to involve patients in shared decision-making. PMID:27574371

  2. Porous alumina scaffold produced by sol-gel combined polymeric sponge method

    NASA Astrophysics Data System (ADS)

    Hasmaliza, M.; Fazliah, M. N.; Shafinaz, R. J.

    2012-09-01

    Sol gel is a novel method used to produce high purity alumina with nanometric scale. In this study, three-dimensional porous alumina scaffold was produced using sol-gel polymeric sponge method. Briefly, sol gel alumina was prepared by evaporation and polymeric sponge cut to designated sizes were immersed in the sol gel followed by sintering at 1250 and 1550°C. In order to study the cell interaction, the porous alumina scaffold was sterilized using autoclave prior to Human Mesenchymal Stem Cells (HMSCs) seeding on the scaffold and the cell proliferation was assessed by alamarBlue® assay. SEM results showed that during the 21 day period, HMSCs were able to attach on the scaffold surface and the interconnecting pores while maintaining its proliferation. These findings suggested the potential use of the porous alumina produced as a scaffold for implantation procedure.

  3. Determinants of methotrexate adherence in rheumatoid arthritis patients.

    PubMed

    De Cuyper, Ellen; De Gucht, Veronique; Maes, Stan; Van Camp, Yoleen; De Clerck, Luc S

    2016-05-01

    In rheumatoid arthritis (RA) patients, weekly intake of methotrexate (MTX) is the basic drug treatment. This observational study aims to investigate how many RA patients are adherent in terms of MTX intake and to identify determinants of non-adherence. Intake of MTX (orally or via injection) was recorded in 129 RA patients with an electronic monitoring system (MEMS(®)) during 16 weeks. In addition, two adherence questionnaires, the Medication Adherence Report Scale (MARS-5) and the Compliance-Questionnaire-Rheumatology (CQR) as well as a visual analogue scale (VAS) measuring MTX adherence, were administered to these patients. As possible determinants of adherence, data on demographics, disease and treatment characteristics, depression, illness cognitions, motivation, and social support were collected. Of all participants, 58 % were fully adherent and 75 % skipped at most one dose during 16 weeks. A better mental health status and suffering from comorbidities had a positive effect on adherence, while living alone had a negative effect. These three predictors explained 30 % of the variance in MTX adherence. Of the three self-report medication adherence measures, the VAS correlated the highest with the results of the electronic monitoring system (r = 0.552, p = 0.01). A relatively high adherence rate was observed in RA patients treated with MTX. The determinants identified by this study could be used to screen patients at risk for non-adherence. A simple VAS scale seems to be an acceptable way for a preliminary screening of MTX adherence. PMID:26781783

  4. Nickel in high-alumina basalts

    USGS Publications Warehouse

    Hedge, C.E.

    1971-01-01

    New analyses of high-alumina basalts reveal an average nickel content higher than previously indicated. Ni in high-alumina basalts correlates with magnesium in the same way as it does in other basalt types. There is therefore no reason, based on Ni contents, to hypothesize a special origin for high-alumina basalts and it is permissible (based on Ni contents) to form andesites by fractional crystallization from high-alumina basalts. ?? 1971.

  5. Attrition resistant gamma-alumina catalyst support

    DOEpatents

    Singleton, Alan H.; Oukaci, Rachid; Goodwin, James G.

    2006-03-14

    A .gamma.-alumina catalyst support having improved attrition resistance produced by a method comprising the steps of treating a particulate .gamma.-alumina material with an acidic aqueous solution comprising water and nitric acid and then, prior to adding any catalytic material thereto, calcining the treated .gamma.-alumina.

  6. Microbicide clinical trial adherence: insights for introduction.

    PubMed

    Woodsong, Cynthia; MacQueen, Kathleen; Amico, K Rivet; Friedland, Barbara; Gafos, Mitzy; Mansoor, Leila; Tolley, Elizabether; McCormack, Sheena

    2013-01-01

    After two decades of microbicide clinical trials it remains uncertain if vaginally- delivered products will be clearly shown to reduce the risk of HIV infection in women and girls. Furthermore, a microbicide product with demonstrated clinical efficacy must be used correctly and consistently if it is to prevent infection. Information on adherence that can be gleaned from microbicide trials is relevant for future microbicide safety and efficacy trials, pre-licensure implementation trials, Phase IV post-marketing research, and microbicide introduction and delivery. Drawing primarily from data and experience that has emerged from the large-scale microbicide efficacy trials completed to-date, the paper identifies six broad areas of adherence lessons learned: (1) Adherence measurement in clinical trials, (2) Comprehension of use instructions/Instructions for use, (3) Unknown efficacy and its effect on adherence/Messages regarding effectiveness, (4) Partner influence on use, (5) Retention and continuation and (6) Generalizability of trial participants' adherence behavior. Each is discussed, with examples provided from microbicide trials. For each of these adherence topics, recommendations are provided for using trial findings to prepare for future microbicide safety and efficacy trials, Phase IV post-marketing research, and microbicide introduction and delivery programs. PMID:23561044

  7. Oral anticancer agent medication adherence by outpatients.

    PubMed

    Kimura, Michio; Usami, Eiseki; Iwai, Mina; Nakao, Toshiya; Yoshimura, Tomoaki; Mori, Hiromi; Sugiyama, Tadashi; Teramachi, Hitomi

    2014-11-01

    In the present study, medication adherence and factors affecting adherence were examined in patients taking oral anticancer agents. In June 2013, 172 outpatients who had been prescribed oral anticancer agents by Ogaki Municipal Hospital (Ogaki, Gifu, Japan) completed a questionnaire survey, with answers rated on a five-point Likert scale. The factors that affect medication adherence were evaluated using a customer satisfaction (CS) analysis. For patients with good and insufficient adherence to medication, the median ages were 66 years (range, 21-85 years) and 73 years (range, 30-90 years), respectively (P=0.0004), while the median dosing time was 131 days (range, 3-3,585 days) and 219 days (24-3,465 days), respectively (P=0.0447). In 36.0% (62 out of 172) of the cases, there was insufficient medication adherence; 64.5% of those cases (40 out of 62) showed good medication compliance (4-5 point rating score). However, these patients did not fully understand the effects or side-effects of the drugs, giving a score of three points or less. The percentage of patients with good medication compliance was 87.2% (150 out of 172). Through the CS analysis, three items, the interest in the drug, the desire to consult about the drug and the condition of the patient, were extracted as items for improvement. Overall, the medication compliance of the patients taking the oral anticancer agents was good, but the medication adherence was insufficient. To improve medication adherence, a better understanding of the effectiveness and necessity of drugs and their side-effects is required. In addition, the interest of patients in their medication should be encouraged and intervention should be tailored to the condition of the patient. These steps should lead to improved medication adherence. PMID:25295117

  8. Oral anticancer agent medication adherence by outpatients

    PubMed Central

    KIMURA, MICHIO; USAMI, EISEKI; IWAI, MINA; NAKAO, TOSHIYA; YOSHIMURA, TOMOAKI; MORI, HIROMI; SUGIYAMA, TADASHI; TERAMACHI, HITOMI

    2014-01-01

    In the present study, medication adherence and factors affecting adherence were examined in patients taking oral anticancer agents. In June 2013, 172 outpatients who had been prescribed oral anticancer agents by Ogaki Municipal Hospital (Ogaki, Gifu, Japan) completed a questionnaire survey, with answers rated on a five-point Likert scale. The factors that affect medication adherence were evaluated using a customer satisfaction (CS) analysis. For patients with good and insufficient adherence to medication, the median ages were 66 years (range, 21–85 years) and 73 years (range, 30–90 years), respectively (P=0.0004), while the median dosing time was 131 days (range, 3–3,585 days) and 219 days (24–3,465 days), respectively (P=0.0447). In 36.0% (62 out of 172) of the cases, there was insufficient medication adherence; 64.5% of those cases (40 out of 62) showed good medication compliance (4–5 point rating score). However, these patients did not fully understand the effects or side-effects of the drugs, giving a score of three points or less. The percentage of patients with good medication compliance was 87.2% (150 out of 172). Through the CS analysis, three items, the interest in the drug, the desire to consult about the drug and the condition of the patient, were extracted as items for improvement. Overall, the medication compliance of the patients taking the oral anticancer agents was good, but the medication adherence was insufficient. To improve medication adherence, a better understanding of the effectiveness and necessity of drugs and their side-effects is required. In addition, the interest of patients in their medication should be encouraged and intervention should be tailored to the condition of the patient. These steps should lead to improved medication adherence. PMID:25295117

  9. Adherence to Sublingual Immunotherapy.

    PubMed

    Incorvaia, Cristoforo; Mauro, Marina; Leo, Gualtiero; Ridolo, Erminia

    2016-02-01

    Adherence is a major issue in any medical treatment. Allergen immunotherapy (AIT) is particularly affected by a poor adherence because a flawed application prevents the immunological effects that underlie the clinical outcome of the treatment. Sublingual immunotherapy (SLIT) was introduced in the 1990s, and the early studies suggested that adherence and compliance to such a route of administration was better than the traditional subcutaneous route. However, the recent data from manufacturers revealed that only 13% of patients treated with SLIT reach the recommended 3-year duration. Therefore, improved adherence to SLIT is an unmet need that may be achieved by various approaches. The utility of patient education and accurate monitoring during the treatment was demonstrated by specific studies, while the success of technology-based tools, including online platforms, social media, e-mail, and a short message service by phone, is currently considered to improve the adherence. This goal is of pivotal importance to fulfill the object of SLIT that is to modify the natural history of allergy, ensuring a long-lasting clinical benefit, and a consequent pharmaco-economic advantage, when patients complete at least a 3-year course of treatment. PMID:26758865

  10. Alumina-Enhanced Thermal Barrier

    NASA Technical Reports Server (NTRS)

    Smith, Marnell; Leiser, Dan; Goldstein, Howard

    1989-01-01

    Rigid, fibrous ceramic tile material called "alumina-enhanced thermal barrier" (AETB) extends temperature capability of insulating materials. Material has obvious potential for terrestrial use in kilns, furnaces, heat engines, and other applications in which light weight and high operating temperature are specified. Three kinds of ceramic fibers are blended, molded, and sintered to make refractory tiles.

  11. Adherence to treatment in adolescents

    PubMed Central

    Taddeo, Danielle; Egedy, Maud; Frappier, Jean-Yves

    2008-01-01

    Health care professionals must be alert to the high prevalence of low adherence to treatment during adolescence. Low adherence increases morbidity and medical complications, contributes to poorer quality of life and an overuse of the health care system. Many different factors have an impact on adherence. However, critical factors to consider in teens are their developmental stage and challenges, emotional issues and family dysfunction. Direct and indirect methods have been described to assess adherence. Eliciting an adherence history is the most useful way for clinicians to evaluate adherence, and could be the beginning of a constructive dialogue with the adolescent. Interventions to improve adherence are multiple – managing mental health issues appropriately, building a strong relationship, customizing the treatment regimen if possible, empowering the adolescent to deal with adherence issues, providing information, ensuring family and peer support, and motivational enhancement therapy. Evaluation of adherence at regular intervals should be an important aspect of health care for adolescents. PMID:19119348

  12. Bacteria repelling on highly-ordered alumina-nanopore structures

    PubMed Central

    Kim, Sunghan; Cirillo, Jeffrey D.; Polycarpou, Andreas A.; Liang, Hong

    2015-01-01

    Bacteria introduce diseases and infections to humans by their adherence to biomaterials, such as implants and surgical tools. Cell desorption is an effective step to reduce such damage. Here, we report mechanisms of bacteria desorption. An alumina nanopore structure (ANS) with pore size of 35 nm, 55 nm, 70 nm, and 80 nm was used as substrate to grow Escherichia coli (E. coli) cells. A bacteria repelling experimental method was developed to quantitatively evaluate the area percentage of adherent bacterial cells that represent the nature of cell adhesion as well as desorption. Results showed that there were two crucial parameters: contact angle and contact area that affect the adhesion/desorption. The cells were found to be more easily repelled when the contact angle increased. The area percentage of adherent bacterial cells decreased with the decrease in the contact area of a cell on ANS. This means that cell accessibility on ANS depends on the contact area. This research reveals the effectiveness of the nanopored structures in repelling cells. PMID:25944966

  13. Bacteria repelling on highly-ordered alumina-nanopore structures

    NASA Astrophysics Data System (ADS)

    Kim, Sunghan; Zhou, Yan; Cirillo, Jeffrey D.; Polycarpou, Andreas A.; Liang, Hong

    2015-04-01

    Bacteria introduce diseases and infections to humans by their adherence to biomaterials, such as implants and surgical tools. Cell desorption is an effective step to reduce such damage. Here, we report mechanisms of bacteria desorption. An alumina nanopore structure (ANS) with pore size of 35 nm, 55 nm, 70 nm, and 80 nm was used as substrate to grow Escherichia coli (E. coli) cells. A bacteria repelling experimental method was developed to quantitatively evaluate the area percentage of adherent bacterial cells that represent the nature of cell adhesion as well as desorption. Results showed that there were two crucial parameters: contact angle and contact area that affect the adhesion/desorption. The cells were found to be more easily repelled when the contact angle increased. The area percentage of adherent bacterial cells decreased with the decrease in the contact area of a cell on ANS. This means that cell accessibility on ANS depends on the contact area. This research reveals the effectiveness of the nanopored structures in repelling cells.

  14. Charge-induced reversible bending in nanoporous alumina-aluminum composite

    NASA Astrophysics Data System (ADS)

    Cheng, Chuan; Ngan, A. H. W.

    2013-05-01

    Upon electrical charging, reversible bending was found in nanoporous anodic alumina-aluminum foil composites, as directly observed by an optical microscope and detected by in situ nanoindentation. The bending is thought to be the result of charge-induced surface stresses in the nanoporous alumina. The results suggest the possibility of a type of composite foil materials for applications as micro-scale actuators to transform electrical energy into mechanical energy.

  15. Alumina as a Thermoluminescent Material

    SciTech Connect

    Uzun, Erdem; Yarar, Yasemin

    2007-04-23

    Thermoluminescence dosimeters are extensively used for quantitative dose measurements in various irradiation fields. They are also important for environmental monitoring after nuclear accident and weapon tests. In this work, the principles of TLD dosimeter and characteristics of several TLD materials are presented. Besides, taken into account the importance as a raw material, the utilization of domestic alumina (Al2O3) in TLDs as a thermoluminescent material is discussed.

  16. Packed Alumina Absorbs Hypergolic Vapors

    NASA Technical Reports Server (NTRS)

    Thomas, J. J.; Mauro, D. M.

    1984-01-01

    Beds of activated alumina effective as filters to remove hypergolic vapors from gas streams. Beds absorb such substances as nitrogen oxides and hydrazines and may also absorb acetylene, ethylene, hydrogen sulfide, benzene, butadiene, butene, styrene, toluene, and xoylene. Bed has no moving parts such as pumps, blowers and mixers. Reliable and energy-conservative. Bed readily adapted to any size from small portable units for use where little vapor release is expected to large stationary units for extensive transfer operations.

  17. Symptom severity, self-reported adherence, and electronic pill monitoring in poorly adherent patients with bipolar disorder

    PubMed Central

    Sajatovic, Martha; Levin, Jennifer; Sams, Johnny; Cassidy, Kristin A; Akagi, Kouri; Aebi, Michelle E; Ramirez, Luis F; Safren, Steven A; Tatsuoka, Curtis

    2015-01-01

    Objectives This analysis of screening and baseline data from an ongoing trial examined self-report versus automated adherence monitoring and assessed the relationship between bipolar disorder (BD) symptoms and adherence in 104 poorly adherent individuals. Methods Adherence was measured with the Tablets Routine Questionnaire (TRQ) and the Medication Event Monitoring System (MEMS). Symptoms were measured with the Montgomery–Åsberg Depression Rating Scale (MADRS), the Young Mania Rating Scale (YMRS), and the Brief Psychiatric Rating Scale (BPRS). Results Mean age of the sample was 46.3 years [standard deviation (SD) = 9.41], with 72% (n = 75) women and 71% (n = 74) African American subjects. Adherence improved from screening to baseline with a mean missed drug proportion measured by TRQ of 61.43% (SD = 26.48) versus baseline mean of 46.61% (SD = 30.55). Mean proportion of missed medication using MEMS at baseline was 66.43% (SD = 30.40). Correlation between TRQ and MEMS was 0.47. Correlation between a single index drug and all BD medications was 0.95. Symptoms were generally positively correlated with TRQ (worse adherence = more severe symptoms), but in most instances was only at a trend level (p > 0.05) with the exception of correlation between baseline TRQ and MADRS and BPRS, which were positive (r = 0.20 and r = 0.21, respectively) and significant (p ≤ 0.05). Conclusions In patients with BD, monitoring increased adherence by 15%. MEMS identified 20% more non-adherence than self-report. Using a standard procedure to identify a single index drug for adherence monitoring may be one way to assess global adherence in patients with BD receiving polypharmacy treatment. Greater BD symptom severity may be a clinical indicator to assess for adherence problems. PMID:26529124

  18. Method for preparing Pb-. beta. ''-alumina ceramic

    DOEpatents

    Hellstrom, E.E.

    1984-08-30

    A process is disclosed for preparing impermeable, polycrystalline samples of Pb-..beta..''-alumina ceramic from Na-..beta..''-alumina ceramic by ion exchange. The process comprises two steps. The first step is a high-temperature vapor phase exchange of Na by K, followed by substitution of Pb for K by immersing the sample in a molten Pb salt bath. The result is a polycrystalline Pb-..beta..''-alumina ceramic that is substantially crack-free.

  19. Factors influencing adherence among older people with osteoarthritis.

    PubMed

    Loew, Laurianne; Brosseau, Lucie; Kenny, Glen P; Durand-Bush, Natalie; Poitras, Stéphane; De Angelis, Gino; Wells, George A

    2016-09-01

    This study aims to identify potential factors that could affect adherence and influence the implementation of an evidence-based structured walking program, among older adults diagnosed with knee osteoarthritis. A total of 69 participants with mild to moderate osteoarthritis of the knee fulfilled an online survey on potential factors that could affect their adherence to an evidence-based structured walking program. Adherence with regard to the influencing factors was explored using a logistic regression model. Results tend to show higher odds of adhering to the evidence-based walking program if the participants were supervised (more than 2.9 times as high), supported by family/friends (more than 3.7 times as high), and not influenced by emotional involvement (more than 11 times as high). The odds of adhering were 3.6 times lower for participants who indicated a change in their medication intake and 3.1 times lower for individuals who considered themselves as less physically active (95 % confidence interval (CI)). Our exploratory findings identified and defined potential adherence factors that could guide health professionals in their practice to better identify positive influences and obstacles to treatment adherence, which would lead to the adoption of a more patient-centered approach. A large-scale study is required to clearly delineate the key factors that would influence adherence. We addressed a new knowledge gap by identifying the main strategies to promote the long-term adherence of community-based walking program. PMID:26646111

  20. Assessing adherence in Thai patients taking combination antiretroviral therapy.

    PubMed

    Kerr, S J; Avihingsanon, A; Putcharoen, O; Chetchotisakd, P; Layton, M; Ubolyam, S; Ruxrungtham, K; Cooper, D A; Phanuphak, P; Duncombe, C

    2012-03-01

    In settings where medications and viral load (VL) monitoring are limited by cost, clinicians need reliable ways to assess patient adherence to therapy. We assessed sensitivity and specificity of two self-reported adherence tools (a visual analogue scale [VAS] and the CASE [Center for Adherence Support Evaluation] adherence index), against a standard of detectable VL, with 288 patients from three sites in Thailand. We also assessed predictors of non-adherence. The sensitivity and specificity of the VAS <95% and CASE adherence index ≤11 against a VL >50 copies/mL were 26% and 90%, 19% and 95%, respectively. Against a VL ≥1000 copies/mL sensitivities increased to 55% and 36%, respectively, and specificities were unchanged. Attending a clinic not staffed by HIV specialists (odds ratio [OR] 3.14; 95% confidence interval [CI] 1.19-8.34) and being educated to primary school level or less (OR 2.24; 95% CI 1.01-4.94) were associated with self-reported adherence <95% on the VAS in multivariate analysis. Adherence assessed by the VAS was a more accurate predictor of detectable VL. Policy-makers in resource-limited settings should ensure that treatment centres are staffed with well-trained personnel aware of the importance of good patient adherence. PMID:22581867

  1. Physical chemistry of carbothermic reduction of alumina

    SciTech Connect

    Frank, Robert A.

    1985-09-01

    Production of aluminium, by means of carbothermic reduction of alumina, is discussed. By employing a solvent metal bath to absorb the alumina metal, carbothermic reduction of alumina was accomplished at temperatures 300/degree/C lower than the temperatures reported in the literature. Reduction occurred without the formation of intermediate compounds and without the high volatilization of aluminum bearing species. Reduction of alumina immersed in a solvent bath appeared to be rate limited by chemical reaction control. The rates seemed to be a function of the activity of aluminum in the solvent metal bath. Reduction of alumina particles, above the surface of the bath, seemed to occur via vapor transport with carbon in the particles or in the crucible walls. Mass transport in the gas phase appeared to be rate limiting. The rates seemed to be a function of the distance separating the alumina and carbon sources. With both submerged alumina and alumina particles, increasing the surface area of the alumina increased the rate of reduction. 58 refs., 65 figs., 9 tabs.

  2. Microwave sintering of large alumina bodies

    SciTech Connect

    Blake, R.D.; Katz, J.D.

    1993-05-01

    The application of microwaves as an energy source for materials processing of large alumina bodies at elevated temperatures has been limited to date. Most work has concerned itself with small laboratory samples. The nonuniformity of the microwave field within a cavity subjects large alumina bodies to areas of concentrated energy, resulting in uneven heating and subsequent cracking. Smaller bodies are not significantly affected by field nonuniformity due to their smaller mass. This work will demonstrate a method for microwave sintering of large alumina bodies while maintaining their structural integrity. Several alumina configurations were successfully sintered using a method which creates an artificial field or environment within the microwave cavity.

  3. Microwave sintering of large alumina bodies

    SciTech Connect

    Blake, R.D.; Katz, J.D.

    1993-01-01

    The application of microwaves as an energy source for materials processing of large alumina bodies at elevated temperatures has been limited to date. Most work has concerned itself with small laboratory samples. The nonuniformity of the microwave field within a cavity subjects large alumina bodies to areas of concentrated energy, resulting in uneven heating and subsequent cracking. Smaller bodies are not significantly affected by field nonuniformity due to their smaller mass. This work will demonstrate a method for microwave sintering of large alumina bodies while maintaining their structural integrity. Several alumina configurations were successfully sintered using a method which creates an artificial field or environment within the microwave cavity.

  4. Perfluoropolyalkylether decomposition on catalytic aluminas

    NASA Technical Reports Server (NTRS)

    Morales, Wilfredo

    1994-01-01

    The decomposition of Fomblin Z25, a commercial perfluoropolyalkylether liquid lubricant, was studied using the Penn State Micro-oxidation Test, and a thermal gravimetric/differential scanning calorimetry unit. The micro-oxidation test was conducted using 440C stainless steel and pure iron metal catalyst specimens, whereas the thermal gravimetric/differential scanning calorimetry tests were conducted using catalytic alumina pellets. Analysis of the thermal data, high pressure liquid chromatography data, and x-ray photoelectron spectroscopy data support evidence that there are two different decomposition mechanisms for Fomblin Z25, and that reductive sites on the catalytic surfaces are responsible for the decomposition of Fomblin Z25.

  5. Reconceptualizing medication adherence: six phases of dynamic adherence.

    PubMed

    Gearing, Robin E; Townsend, Lisa; MacKenzie, Michael; Charach, Alice

    2011-01-01

    Nonadherence is the Achilles' heel of effective psychiatric treatment. It affects the resolution of mental health symptoms and interferes with the assessment of treatment response. The meaning of the term adherence has evolved over time and is now associated with a variety of definitions and measurement methods. The result has been a poorly operationalized and nonstandardized term that is often interpreted differently by providers and patients. Drawing extensively from the literature, this article aims to (1) describe changes in the concept of adherence, drawing from the mental health treatment literature, (2) present a more comprehensive definition of adherence that recognizes the role of patient-provider transactions, (3) introduce dynamic adherence, a six-phase model, which incorporates the role of transactional processes and other factors that influence patients' adherence decisions, and (4) provide recommendations for providers to improve adherence as well as their relationships with patients. PMID:21790266

  6. Development of Alumina-Forming Austenitic Stainless Steels

    SciTech Connect

    Brady, Michael P; Yamamoto, Yukinori; Bei, Hongbin; Santella, Michael L; Maziasz, Philip J

    2009-01-01

    This paper presents the results of the continued development of creep-resistant, alumina-forming austenitic (AFA) stainless steel alloys, which exhibit a unique combination of excellent oxidation resistance via protective alumina (Al2O3) scale formation and high-temperature creep strength through the formation of stable nano-scale MC carbides and intermetallic precipitates. Efforts in fiscal year 2009 focused on the characterization and understanding of long-term oxidation resistance and tensile properties as a function of alloy composition and microstructure. Computational thermodynamic calculations of the austenitic matrix phase composition and the volume fraction of MC, B2-NiAl, and Fe2(Mo,Nb) base Laves phase precipitates were used to interpret oxidation behavior. Of particular interest was the enrichment of Cr in the austenitic matrix phase by additions of Nb, which aided the establishment and maintenance of alumina. Higher levels of Nb additions also increased the volume fraction of B2-NiAl precipitates, which served as an Al reservoir during long-term oxidation. Ageing studies of AFA alloys were conducted at 750 C for times up to 2000 h. Ageing resulted in near doubling of yield strength at room temperature after only 50 h at 750 C, with little further increase in yield strength out to 2000 h of ageing. Elongation was reduced on ageing; however, levels of 15-25% were retained at room temperature after 2000 h of total ageing.

  7. Materials Adherence Experiment: Technology

    SciTech Connect

    Jenkins, P.P.; Landis, G.A.; Oberle, L.G.

    1997-12-31

    NASA`s Mars Pathfinder mission, launched December 4, 1996, reflects a new philosophy of exploiting new technologies to reduce mission cost and accelerate the pace of space exploration. Pathfinder will demonstrate a variety of new technologies aimed at reducing the cost of Mars exploration. Chief among these will be the demonstration of a solar-powered spacecraft on the surface of Mars. The Materials Adherence Experiment on Pathfinder was designed to measure the degradation of solar arrays due to dust settling out of the atmosphere and blocking light to the solar array, lowering the array power output.

  8. Formation of alumina-nickel-molybdenum catalysts

    SciTech Connect

    Erofeev, V.I.; Basov, V.G.; Vagin, A.I.; Kalechits, I.V.

    1982-06-01

    On the basis of the results obtained in physical and chemical studies of alumina-nickel-molybdenum oxide catalysts as well as binary system and the individual oxides, the conclusions show that the commercial catalyst consists mainly of nickel and aluminium molybdates, aluminium molybdates, molybdenum oxide, and the alumina support. 4 figures.

  9. Effects of Impurities on Alumina-Niobium InterfacialMicrostructures

    SciTech Connect

    McKeown, Joseph T.; Sugar, Joshua D.; Gronsky, Ronald; Glaeser,Andreas M.

    2005-06-20

    Optical microscopy, scanning electron microscopy, and transmission electron microscopy were employed to examine the interfacial microstructural effects of impurities in alumina substrates used to fabricate alumina-niobium interfaces via liquid-film-assisted joining. Three types of alumina were used: undoped high-purity single-crystal sapphire; a high-purity, high-strength polycrystalline alumina; and a lower-purity, lower-strength polycrystalline alumina. Interfaces formed between niobium and both the sapphire and high-purity polycrystalline alumina were free of detectable levels of impurities. In the lower-purity alumina, niobium silicides were observed at the alumina-niobium interface and on alumina grain boundaries near the interface. These silicides formed in small-grained regions of the alumina and were found to grow from the interface into the alumina along grain boundaries. Smaller silicide precipitates found on grain boundaries are believed to form upon cooling from the bonding temperature.

  10. Associations between patient factors and medication adherence: A Jordanian experience

    PubMed Central

    Basheti, Iman A.; Hait, Sami Saqf El; Qunaibi, Eyad A.; Aburuz, Salah; Bulatova, Nailya

    2015-01-01

    Objective: To explore the effect of patient characteristics and health beliefs on their medication adherence. Methods: Patients (n=167) with chronic conditions (mean age 58.9; SD=13.54, 53% males) were recruited from March 2009- to March 2010 using a cross sectional study design. Data collected included patients’ demographics, medical conditions, medications therapeutic regimen, frequency of physician visits and health beliefs. Patient self-reported adherence to medications was assessed by the researcher using a validated and published scale. Treatment related problems (TRPs) were evaluated for each patient by competent clinical pharmacists. Associations between patient characteristics/health beliefs with adherence were explored. Results: About half of the patients (46.1%) were non-adherent. A significant association was found between lower adherence and higher number of disease states (p<0.001), higher number of medications (p=0.001), and higher number of identified TRPs (p = 0.003). Patient adherence was positively affected by older age, higher educational level, and higher number of physician visits per month, while it was negatively affected by reporting difficulties with getting prescription refills on time. Conclusion: This study identified different factors that may negatively affect adherence, including higher number of medications and disease states, higher number of identified TRPs and inability to getting prescription refills on time. Hence, more care needs to be provided to patients with complex therapeutic regimens in order to enhance adherence. PMID:27011772

  11. Medication Adherence and Treatment Satisfaction Among Renal Transplant Recipients.

    PubMed

    Alkatheri, Abdulmalik A; Albekairy, Abdulkareem M; Jarab, Anan; Bustami, Rami; Khalidi, Nabil; Alshaya, Abdulrahman; Bin Saleh, Khalid; Alraddadi, Sultan; Alharbi, Shmeylan; Vasudevan, Senthilvel; Alsayyari, Abdullah; Qandil, Amjad M

    2016-01-01

    BACKGROUND Evidence suggests that patients who are more satisfied with their treatment show better adherence with the prescribed therapy. Although there is valuable data about medication adherence among renal transplant recipients (RTRs), there is a limited literature about their treatment satisfaction and its relation to adherence. The aim of the present study was to investigate factors that can predict medication adherence and to explore the relationship between treatment satisfaction and medication adherence in renal transplant recipients. MATERIAL AND METHODS Adult RTRs were included in the study using convenient sampling. The participants were asked to complete the 8-item Morisky Medication Adherence Scale (MMAS-8) and Treatment Satisfaction Scale TSQM 1.4 in addition to several socio-demographic and treatment-related data. The results were statistically analyzed using univariate and multivariate logistic regression modelling in a stepwise procedure. RESULTS A total of 151 RTRs were included in the study, of which 52 were classified as adherent (34%). Univariate analysis showed that, in comparison with non-adherent RTRs, the adherent group demonstrated significantly higher satisfaction scores in the domains of convenience (96.6±8.7 vs. 85.3±19.3), side effects (95.9±14.1 vs. 82.6±24.1), and global satisfaction (93.4±9.8 vs. 86.7±16.7), while they had marginally higher satisfaction scores in the effectiveness domain (90.4±11.6 vs. 86.5±14.5). Results from multiple logistic regression showed that higher likelihood of adherence was significantly associated with increased satisfaction score in the convenience domain [AOR=1.76, 95% CI=(1.21, 2.55); p=0.003] and marginally related to increased satisfaction scores in the side effects domain [AOR=1.31, 95% CI=(0.99, 1.74); p=0.061]. Male RTRs were significantly more likely to be adherent than female RTRs [AOR=2.23, 95% CI=(1.02, 4.84); p=0.043]. CONCLUSIONS Although the adherence rate among RTRs is relatively

  12. Electrochemically replicated smooth aluminum foils for anodic alumina nanochannel arrays.

    PubMed

    Biring, Sajal; Tsai, Kun-Tong; Sur, Ujjal Kumar; Wang, Yuh-Lin

    2008-01-01

    A fast electrochemical replication technique has been developed to fabricate large-scale ultra-smooth aluminum foils by exploiting readily available large-scale smooth silicon wafers as the masters. Since the adhesion of aluminum on silicon depends on the time of surface pretreatment in water, it is possible to either detach the replicated aluminum from the silicon master without damaging the replicated aluminum and master or integrate the aluminum film to the silicon substrate. Replicated ultra-smooth aluminum foils are used for the growth of both self-organized and lithographically guided long-range ordered arrays of anodic alumina nanochannels without any polishing pretreatment. PMID:21730530

  13. Fabrication of dense α-alumina layer on Ti-6Al-4V alloy hybrid for bearing surfaces of artificial hip joint.

    PubMed

    Khanna, Rohit; Kokubo, Tadashi; Matsushita, Tomiharu; Takadama, Hiroaki

    2016-12-01

    Recent advances in hip replacements are focused towards producing reliable bearing surfaces to enhance their longevity. In this perspective, progressive attempts have been made to improve the wear resistance of polyethylene to eliminate osteolysis and mechanical reliability of brittle alumina ceramics, but in vain. It is proposed that both high wear resistance and mechanical reliability can be retained if a thin layer of dense alumina is formed onto high toughness Ti-6Al-4V alloy. For this purpose, we devised a unique methodology in which a layer of Al metal was deposited onto the Ti alloy substrate by cold spraying (CS), followed by a heat treatment to form Al3Ti reaction layer at their interface to improve adhesion and subsequent micro-arc oxidation (MAO) treatment to transform Al to alumina layer. An optimal MAO treatment of cold sprayed Al formed an adherent and dense α-alumina layer with high Vickers hardness matching with that of sintered alumina used as a femoral head. Structure-phase-property relationships in dense α-alumina layer have been revealed and discussed in the light of our research findings. The designed alumina/Ti alloy hybrid might be a potential candidate for reliable bearing surfaces of artificial hip joint. PMID:27612821

  14. [Adherence to psychopharmacological treatment: Psychotherapeutic strategies to enhance adherence].

    PubMed

    Lencer, R; Korn, D

    2015-05-01

    Effective psychopharmacological medication with good tolerability represents the cornerstone of treatment for severe mental illness; however, the 1-year adherence rates are only approximately 50%. The term adherence emphasizes the collaborative responsibility of the clinician and the patient for a positive treatment outcome. Reasons for non-adherence are manifold and include patient-specific factors, such as self-stigmatization, lack of social and familial support, cognitive impairment and substance use besides insufficient effectiveness and the occurrence of side effects of the psychotropic drugs. To enhance adherence, both clinician and patient have to fully understand all the reasons for and against adherence to medication before a collaborative decision is made on future long-term treatment. A positive attitude towards medication critically depends on whether patients feel that the medication supports the attainment of the individual goals. PMID:25903501

  15. Characterization and application of electrospun alumina nanofibers

    PubMed Central

    2014-01-01

    Alumina nanofibers were prepared by a technique that combined the sol–gel and electrospinning methods. The solution to be electrospun was prepared by mixing aluminum isopropoxide (AIP) in ethanol, which was then refluxed in the presence of an acid catalyst and polyvinylpyrolidone (PVP) in ethanol. The characterization results showed that alumina nanofibers with diameters in the range of 102 to 378 nm were successfully prepared. On the basis of the results of the XRD and FT-IR, the alumina nanofibers calcined at 1,100°C were identified as comprising the α-alumina phase, and a series of phase transitions such as boehmite → γ-alumina → α-alumina were observed from 500°C to 1,200°C. The pore size of the obtained γ-alumina nanofibers is approximately 8 nm, and it means that they are mesoporous materials. The kinetic study demonstrated that MO adsorption on alumina nanofibers can be seen that the pseudo-second-order kinetic model fits better than the pseudo-first-order kinetic model. PMID:24467944

  16. Monitoring Transport Across Modified Nanoporous Alumina Membranes

    PubMed Central

    Penumetcha, Sai S.; Kona, Ravikanth; Hardin, Jonathan L.; Molder, Andrew L.; Steinle, Erich D.

    2007-01-01

    This paper describes the use of several characterization methods to examine alumina nanotubule membranes that have been modified with specific silanes. The function of these silanes is to alter the transport properties through the membrane by changing the local environment inside the alumina nanotube. The presence of alkyl groups, either long (C18) or short and branched (isopropyl) hydrocarbon chains, on these silanes significantly decreases the rate of transport of permeant molecules through membranes containing alumina nanotubes as monitored via absorbance spectroscopy. The presence of an ionic surfactant can alter the polarity of these modified nanotubes, which correlates to an increased transport of ions. Fluorescent spectroscopy is also utilized to enhance the sensitivity of detecting these permeant molecules. Confirmation of the alkylsilane attachment to the alumina membrane is achieved with traditional infrared spectroscopy, which can also examine the lifetime of the modified membrane. The physical parameters of these silane-modified porous alumina membranes are studied via scanning electron microscopy. The alumina nanotubes are not physically closed off or capped by the silanes that are attached to the alumina surfaces.

  17. Laser carbonitriding of alumina surface

    NASA Astrophysics Data System (ADS)

    Yilbas, B. S.; Akhtar, S. S.; Karatas, C.

    2011-03-01

    Laser carbonitriding of alumina surfaces is examined. Temperature and stress fields developed during the laser heating of the substrate surface are predicted using the finite element method in line with the experimental conditions. The formation of Al(C, N) and AlN compounds in the surface region of irradiated workpiece is examined using X-ray Photoelectron Spectroscopy (XPS) and X-ray Diffraction (XRD). The microstructural and morphological changes in the laser irradiated region are examined using Scanning Electron Microscope (SEM). The microhardness of the resulting surface is measured and compared with the base material hardness. It is found that high temperature gradient is developed in the irradiated region, which in turn, results in high residual stress levels in this region. XPS and XRD data reveal the presence of Al (C, N) and AlN compounds in the surface region. The microhardness in the surface region of the laser treated workpiece increases significantly.

  18. Dissolution Kinetics of Alumina Calcine

    SciTech Connect

    Batcheller, Thomas Aquinas

    2001-09-01

    Dissolution kinetics of alumina type non-radioactive calcine was investigated as part of ongoing research that addresses permanent disposal of Idaho High Level Waste (HLW). Calcine waste was produced from the processing of nuclear fuel at the Idaho Nuclear Technology and Engineering Center (INTEC). Acidic radioactive raffinates were solidified at ~500°C in a fluidized bed reactor to form the dry granular calcine material. Several Waste Management alternatives for the calcine are presented in the Idaho High Level Waste Draft EIS. The Separations Alternative addresses the processing of the calcine so that the HLW is ready for removal to a national geological repository by the year 2035. Calcine dissolution is the key front-end unit operation for the separations alternative.

  19. Fabrication of thin layer beta alumina

    NASA Technical Reports Server (NTRS)

    Tennenhouse, G. J.

    1977-01-01

    Beta alumina tubes having walls 700 microns, 300 microns, and 140 microns were processed by extrusion and sintering utilizing Ford proprietary binder and fabrication systems. Tubes prepared by this method have properties similar to tubes prepared by isostatic pressing and sintering, i.e. density greater than 98% of theoretical and a helium leak rate less than 3 x 10 to the -9th power cc/sq cm/sec. Ford ultrasonic bonding techniques were used for bonding beta alumina end caps to open ended beta -alumina tubes prior to sintering. After sintering, the bond was hermetic, and the integrity of the bonded area was comparable to the body of the tube.

  20. Race and Residential Socioeconomics as Predictors of CPAP Adherence

    PubMed Central

    Billings, Martha E.; Auckley, Dennis; Benca, Ruth; Foldvary-Schaefer, Nancy; Iber, Conrad; Redline, Susan; Rosen, Carol L.; Zee, Phyllis; Kapur, Vishesh K.

    2011-01-01

    Study Objectives: There are few established predictors of CPAP adherence; poor adherence limits its effectiveness. We investigated whether race, education level, and residential economic status predict CPAP adherence in participants enrolled in a trial with standard access to treatment. Design: A multi-center randomized trial of home vs. lab-based evaluation and treatment of OSA assessing adherence to CPAP at 1 and 3 months. Setting: Seven AASM-accredited sleep centers in 5 U.S. cities. Participants: Subjects with moderate to severe OSA (AHI ≥ 15 and Epworth Sleepiness Scale score > 12) who completed follow-up at 1 and/or 3 months (n = 135). Measurements and Results: Subjects' demographic data were collected upon enrollment; CPAP use at 1 and 3 months was assessed at clinic follow-up. In unadjusted analyses, CPAP adherence (average minutes per night of CPAP use) at 3 months was lower in black subjects and in subjects from lower socioeconomic status ZIP codes. In adjusted analyses using multivariate linear regression, black race was predictive of CPAP adherence at one month (P = 0.03). At 3 months, black race was predictive in analyses only when ZIP code SES was not adjusted for. Conclusion: Black race and lower socioeconomic residential areas are associated with poorer adherence to CPAP in subjects with standardized access to care and treatment. Disparities remain despite provision of standardized care in a clinical trial setting. Future research is needed to identify barriers to adherence and to develop interventions tailored to improve CPAP adherence in at risk populations. Portable Monitoring for Diagnosis and Management of Sleep Apnea (HomePAP) Clinical Trial Information: NIH clinical trials registry number: NCT00642486. URL: http://clinicaltrials.gov/show/NCT00642486. Citation: Billings ME; Auckley D; Benca R; Foldvary-Schaefer N; Iber C; Redline S; Rosen CL; Zee P; Kapur VK. Race and residential socioeconomics as predictors of CPAP adherence. SLEEP 2011

  1. Improved adherence with contingency management.

    PubMed

    Rosen, Marc I; Dieckhaus, Kevin; McMahon, Thomas J; Valdes, Barbara; Petry, Nancy M; Cramer, Joyce; Rounsaville, Bruce

    2007-01-01

    Contingency management (CM) based interventions that reinforce adherence to prescribed medications have shown promise in a variety of disadvantaged populations. Fifty-six participants with histories of illicit substance use who were prescribed antiretroviral medication but evidenced suboptimal adherence during a baseline assessment were randomly assigned to 16 weeks of weekly CM-based counseling or supportive counseling, followed by 16 additional weeks of data collection and adherence feedback to providers. The CM intervention involved review of data generated by electronic pill-bottle caps that record bottle opening (MEMS) and brief substance abuse counseling. CM participants were reinforced for MEMS-measured adherence with drawings from a bowl for prizes and bonus drawings for consecutive weeks of perfect adherence. Potential total earnings averaged $800. Mean MEMS-measured adherence to the reinforced medication increased from 61% at baseline to 76% during the 16-week treatment phase and was significantly increased relative to the supportive counseling group (p = 0.01). Furthermore, mean log-transformed viral load was significantly lower in the CM group. However, by the end of the 16-week follow-up phase, differences between groups in adherence and viral load were no longer significantly different. Proportions of positive urine toxicology tests did not differ significantly between the two groups at any phase. A brief CM-based intervention was associated with significantly higher adherence and lower viral loads. Future studies should evaluate methods to extend effects for longer term benefits. PMID:17263651

  2. Antidepressant adherence after psychiatric hospitalization

    PubMed Central

    Zivin, Kara; Ganoczy, Dara; Pfeiffer, Paul N.; Miller, Erin M.; Valenstein, Marcia

    2010-01-01

    Objective Depressed patients discharged from psychiatric hospitalizations face increased risks for adverse outcomes including suicide, yet antidepressant adherence rates during this high-risk period are unknown. Using Veterans Affairs (VA) data, we assessed antidepressant adherence and predictors of poor adherence among depressed veterans following psychiatric hospitalization. Method We identified VA patients nationwide with depressive disorders who had a psychiatric hospitalization between April 1, 1999 and September 30, 2003, received antidepressant medication, and had an outpatient appointment following discharge. We calculated medication possession ratios (MPRs), a measure of medication adherence, within three and six months following discharge. We assessed patient factors associated with having lower levels of adherence (MPRs <0.8) after discharge. Results 20,931 and 23,182 patients met criteria for three and six month MPRs. The mean three month MPR was 0.79 (s.d.=0.37). The mean six month MPR was 0.66 (s.d.=0.40). Patients with poorer adherence were male, younger, non-white, and had a substance abuse disorder, but were less likely to have PTSD or other anxiety disorders. Conclusion Poor antidepressant adherence is common among depressed patients after psychiatric hospitalization. Efforts to improve adherence at this time may be critical in improving the outcomes of these high-risk patients. PMID:19609666

  3. Biologic Influences on Exercise Adherence.

    ERIC Educational Resources Information Center

    Dishman, Rod K.

    1981-01-01

    Diagnostic profiles of 362 male participants in an exercise program were analyzed to determine the biological variables between exercise adherence and symptoms of coronary disease. Findings indicated that individuals with lower metabolic capacity tended to adhere longer, to be less fit, were leaner, and began with more symptoms related to coronary…

  4. The Effects of Adherence to Non-Steroidal Anti-Inflammatory Drugs and Factors Influencing Drug Adherence in Patients with Knee Osteoarthritis

    PubMed Central

    2016-01-01

    We aimed to compare the clinical outcomes of knee osteoarthritis patients according to drug adherence; and to find out the factors the affecting those outcomes. We analyzed the drug adherence and clinical outcomes in 1,334 primary knee osteoarthritis patients who took non-steroidal anti-inflammatory drugs (NSAIDs) for 3 weeks. Clinical outcomes of Pain Numeric Rating Scale (NRS), Knee injury and Osteoarthritis Outcome Score (KOOS) and EQ-5D were compared at baseline and 3 weeks’ follow-up between the two groups of adherent group and non-adherent group (1,167 vs. 167 patients). Logistic regression analysis was performed to examine the factors affecting the adherence, and the reasons for the non-adherence were asked. The follow-up clinical outcomes of NRS and KOOS symptom, pain and activity of daily life were significantly higher in the adherence group (P = 0.003, P = 0.048, P = 0.005, and P = 0.003, respectively). The adherence was better in the elderly and in the male group (P = 0.042 and P = 0.034, respectively) and the top reason for no strict adherence was “symptom improved” (21.5%) followed by side effects. In this study, the patients with better adherence to NSAIDs showed better outcomes compared to those with poor adherence. This study can contribute to the patient education for the pharmacological treatment in knee OA patients. PMID:27134504

  5. Cast alumina forming austenitic stainless steels

    DOEpatents

    Muralidharan, Govindarajan; Yamamoto, Yukinori; Brady, Michael P

    2013-04-30

    An austenitic stainless steel alloy consisting essentially of, in terms of weight percent ranges 0.15-0.5C; 8-37Ni; 10-25Cr; 2.5-5Al; greater than 0.6, up to 2.5 total of at least one element selected from the group consisting of Nb and Ta; up to 3Mo; up to 3Co; up to 1W; up to 3Cu; up to 15Mn; up to 2Si; up to 0.15B; up to 0.05P; up to 1 total of at least one element selected from the group consisting of Y, La, Ce, Hf, and Zr; <0.3Ti+V; <0.03N; and, balance Fe, where the weight percent Fe is greater than the weight percent Ni, and wherein the alloy forms an external continuous scale comprising alumina, and a stable essentially single phase FCC austenitic matrix microstructure, the austenitic matrix being essentially delta-ferrite free and essentially BCC-phase-free. A method of making austenitic stainless steel alloys is also disclosed.

  6. Corrosion Behaviour of Sputtered Alumina Thin Films

    NASA Astrophysics Data System (ADS)

    Reddy, I. Neelakanta; Dey, Arjun; Sridhara, N.; Anoop, S.; Bera, Parthasarathi; Rani, R. Uma; Anandan, Chinnasamy; Sharma, Anand Kumar

    2015-10-01

    Corrosion studies of sputtered alumina thin films grown on stainless steel (SS) 304 were carried out by linear polarization and electrochemical impedance spectroscopy. Noticeable changes were not observed in morphology and surface roughness of films after carrying out the corrosion test. Corrosion current density (icorr) of alumina coated SS decreased up to 10-10 A cm-2 while icorr value in the range of 10-5-10-6 A cm-2 was observed for bare SS. The direct sputtered film showed superior corrosion resistance behaviour than the reactive sputtered film. This might be attributed to the difference in thickness of the films sputtered by direct and reactive methods. The electronic structure of deposited alumina films was studied both before and after corrosion test by X-ray photoelectron spectroscopy technique which also confirmed no structural changes of alumina film after exposing it to corrosive environment.

  7. Loss tangent measurements on unirradiated alumina

    SciTech Connect

    Zinkle, S.J.; Goulding, R.H.

    1996-04-01

    Unirradiated room temperature loss tangent for sapphire and several commercial grades of polycrystalline alumina are complied for frequencies between 10{sup 5} and 4x10{sup 11} Hz. Sapphire exhibits significantly lower values for the loss tangent at frequencies up to 10{sup 11} Hz. The loss tangents of 3 different grades of Wesgo alumina (AL300, AL995, AL998) and 2 different grades of Coors alumina (AD94, AD995) have typical values near {approx}10{sup -4} at a frequency of 10{sup 8} Hz. On the other hand, the loss tangent of Vitox alumina exhibits a large loss peak tan d{approx} 5x10{sup -3} at this frequency.

  8. Processing of Alumina-Toughened Zirconia Composites

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.; Choi, Sung R.

    2003-01-01

    Dense and crack-free 10-mol%-yttria-stabilized zirconia (10YSZ)-alumina composites, containing 0 to 30 mol% of alumina, have been fabricated by hot pressing. Release of pressure before onset of cooling was crucial in obtaining crack-free material. Hot pressing at 1600 C resulted in the formation of ZrC by reaction of zirconia with grafoil. However, no such reaction was observed at 1500 C. Cubic zirconia and -alumina were the only phases detected from x-ray diffraction indicating no chemical reaction between the composite constituents during hot pressing. Microstructure of the composites was analyzed by scanning electron microscopy and transmission electron microscopy. Density and elastic modulus of the composites followed the rule-of-mixtures. Addition of alumina to 10YSZ resulted in lighter, stronger, and stiffer composites by decreasing density and increasing strength and elastic modulus.

  9. Studies of Plasma-Sprayed Alumina

    NASA Astrophysics Data System (ADS)

    Ilavsky, Jan

    1994-05-01

    Phase transformations and porosity of the plasma sprayed alumina deposits were examined. The dependence of the phase transformations on deposit chemistry was established. Porosity changes during heat treatment were studied and a model for the porosity is proposed. A novel technique in the field of plasma sprayed deposits--small-angle neutron scattering (SANS)--was successfully applied. Deposits were manufactured using the water-stabilized plasma spray system, PAL160, with an input of 160 kW. Phase transformations of the plasma sprayed alumina deposits were studied using XRD and DTA. The deposits were manufactured from 99.9% alumina, alumina-chromia (1.5% Cr_2O_3), gray alumina (3.7% TiO_2) and alumina -titania (17% TiO_2). The addition of chromia increases the temperature of the alpha phase formation by about 40^circ C and the addition of TiO_2 reduces this temperature by about 150^circ C for gray alumina and by about 175^ circC for alumina-titania. The amount of metastable theta phase was found to depend on the chemistry of the feedstock. Porosities of the deposits, made from alumina and gray alumina, were studied using mercury intrusion porosimetry, weighing method (Archimedean porosimetry), image analysis and SANS. Samples were studied in the as -sprayed condition and after heat treatment for 2 hours at 1300^circC and 1500 ^circC. Porosity depends on the deposit chemistry and on the heat treatment and varies from 5% to about 11%. Different porosity measurement techniques yield different results. Surface areas of 1.5 to 7.5 times 10^4 cm^2 /cm^3 (times 10^6 m^{ -1}) were measured using SANS and depend on heat treatment and on the deposit chemistry. The phase transformations can be associated with an increase in pore surface area and decrease in surface area at 1500 ^circC can be associated with sintering. The effective pore radius, R_{ rm eff}, as measured by SANS is a measure of the pore sizes in the 0.08 to 10 μm size range. The R_{rm eff} depends on deposit

  10. Clustering based on adherence data

    PubMed Central

    2011-01-01

    Adherence to a medical treatment means the extent to which a patient follows the instructions or recommendations by health professionals. There are direct and indirect ways to measure adherence which have been used for clinical management and research. Typically adherence measures are monitored over a long follow-up or treatment period, and some measurements may be missing due to death or other reasons. A natural question then is how to describe adherence behavior over the whole period in a simple way. In the literature, measurements over a period are usually combined just by using averages like percentages of compliant days or percentages of doses taken. In the paper we adapt an approach where patient adherence measures are seen as a stochastic process. Repeated measures are then analyzed as a Markov chain with finite number of states rather than as independent and identically distributed observations, and the transition probabilities between the states are assumed to fully describe the behavior of a patient. The patients can then be clustered or classified using their estimated transition probabilities. These natural clusters can be used to describe the adherence of the patients, to find predictors for adherence, and to predict the future events. The new approach is illustrated and shown to be useful with a simple analysis of a data set from the DART (Development of AntiRetroviral Therapy in Africa) trial in Uganda and Zimbabwe. PMID:21385451

  11. Cognitive function and adherence to anticoagulation treatment in patients with atrial fibrillation

    PubMed Central

    Jankowska-Polańska, Beata; Katarzyna, Lomper; Lidia, Alberska; Joanna, Jaroch; Dudek, Krzysztof; Izabella, Uchmanowicz

    2016-01-01

    Background Medication adherence is an integral part of the comprehensive care of patients with atrial fibrillation (AF) receiving oral anticoagulations (OACs) therapy. Many patients with AF are elderly and may suffer from some form of cognitive impairment. This study was conducted to investigate whether cognitive impairment affects the level of adherence to anticoagulation treatment in AF patients. Methods The study involved 111 AF patients (mean age, 73.5 ± 8.3 years) treated with OACs. Cognitive function was assessed using the Mini Mental State Examination (MMSE). The level of adherence was assessed by the 8-item Morisky Medication Adherence Scale (MMAS-8). Scores on the MMAS-8 range from 0 to 8, with scores < 6 reflecting low adherence, 6 to < 8 medium adherence, and 8 high adherence. Results 46.9% of AF patients had low adherence, 18.8% had moderate adherence, and 33.3% had high adherence to OACs. Patients with lower adherence were older than those with moderate or high adherence (76.6 ± 8.7 vs. 71.3 ± 6.4 vs. 71.1 ± 6.7 years) and obtained low MMSE scores, indicating cognitive disorders or dementia (MMSE = 22.3 ± 4.2). Patients with moderate or high adherence obtained high MMSE test results (27.5 ± 1.7 and 27.5 ± 3.6). According to Spearman's rank correlation, worse adherence to treatment with OACs was determined by older age (rS = −0.372) and lower MMSE scores (rS = 0.717). According to multivariate regression analysis, the level of cognitive function was a significant independent predictor of adherence (b = 1.139). Conclusions Cognitive impairment is an independent determinant of compliance with pharmacological therapy in elderly patients with AF. Lower adherence, beyond the assessment of cognitive function, is related to the age of patients. PMID:27605935

  12. Preparation and Characterization of Electrospun Alumina Nanofibers

    NASA Astrophysics Data System (ADS)

    Pinti, Marie J.; Tacastacas, Stephen N.; Stojilovic, Nenad; O'Brien, John P.; Pischera, Anna; Espe, Matthew P.

    2008-10-01

    Alumina nanofibers are promising materials for use in high- temperature applications since they are chemically inert up to very high temperatures. Applications include use as catalyst support in high-temperature chemical reactions, fire protection materials, and as a high-temperature insulator. Electrospinning is a relatively simple and inexpensive method for obtaining nanometer-size fibers and has become a popular technique for producing metal-oxide nanofibers in recent years. The electrospinning mixture for the production of alumina nanofibers typically contains aluminum acetate stabilized with boric acid as the alumina precursor; but the observed presence of boron and sodium on the surface of these nanofibers may affect their use as catalytic supports. We have produced alumina nanofibers from an aluminum reagent devoid of the boric acid stabilizer and calcined the fibers at different temperatures to produce nanofibers with different phases of alumina. Characterization of the fibers by TGA, FE-SEM equipped with the XEDS, powder XRD, DRIFTS, and SSNMR methods to determine the fate of the precursors, fiber morphology and the composition and structure of the calcined alumina nanofibers.

  13. Measuring insulin adherence among adults with type 2 diabetes.

    PubMed

    Osborn, Chandra Y; Gonzalez, Jeffery S

    2016-08-01

    Non-adherence to insulin is common and associated with suboptimal health. We adapted the Morisky Medication Adherence Scale to specify insulin adherence (MIAS) and compared it to the Adherence to Refills and Medication Scale for Diabetes (ARMS-D) and the Summary of Diabetes Self-Care Activities medications subscale (SDSCA-MS) and an insulin-specific (SDSCA-IS) version. A sample of 144 insulin-treated adults (58 % African American/Black, 34 % Caucasian/White, 8 % Other/Mixed race; 6.9 % Hispanic) completed these measures along with a HbA1C test. The internal consistency and factor structure of the MIAS were adequate; 59 % of participants forgot to take insulin and 46 % reported non-adherence. The MIAS was associated with the ARMS-D, SDSCA-MS, and SDSCA-IS (p < 0.001), and higher MIAS scores were marginally associated with better self-rated health (p = 0.057), but significantly associated with fewer emergency room visits (p = 0.001), and better HbA1C (p = 0.001). The MIAS is a valid and reliable insulin adherence assessment tool for practice and research applications. PMID:27062271

  14. Adherence to Antihypertensive Medication in Older Adults With Hypertension

    PubMed Central

    Lo, Suzanne H. S.; Chau, Janita P. C.; Woo, Jean; Thompson, David R.; Choi, Kai Chow

    2016-01-01

    Background/Objectives: Effective prevention of cardiovascular events in people with hypertension requires optimal control of blood pressure. Despite advances in management, poor adherence to antihypertensive medications is often reported as the major reason attenuating treatment efficacy. Research has provided limited evidence of associations between illness perceptions, satisfaction with consultations, and medication adherence. The aim of this study is to identify factors significantly associated with medication adherence in a group of Chinese older adults with essential hypertension. Design/Setting/Participants: A cross-sectional correlational study was conducted. Data were collected from 195 older adults (mean [SD] age, 76 [6.6] years) recruited from 12 community centers. Measurements: The Illness Perception Questionnaire–Revised was used to measure illness perceptions, and the Medical Interview Satisfaction Scale was used to measure satisfaction with individual consultations. The Morisky Medication Adherence Scale was used to measure the extent of adherence to antihypertensive medications. Multivariate logistic regression analysis was performed to examine factors, including illness perceptions, consultation satisfaction, and demographic and clinical characteristics, that were significantly associated with medication adherence. Results: More than half of the respondents (55.9%) acknowledged some degree of medication nonadherence. Older age, living alone, and perception related to treatment control were independently associated with increased odds of medication adherence, with odds ratios ranging from 1.14 to 1.92 (P < .05). Conclusion: The results highlight the importance of cultivating positive beliefs that hypertension is amenable to control by treatment. Furthermore, the adherence behavior of those of younger individuals and living with family should be closely monitored. PMID:25774846

  15. Thirty years of experience with alumina-on-alumina bearings in total hip arthroplasty.

    PubMed

    Hannouche, Didier; Zaoui, Amine; Zadegan, Frédéric; Sedel, Laurent; Nizard, Rémy

    2011-02-01

    Alumina-on-alumina bearings in total hip arthroplasty have been developed in an attempt to minimise debris and the occurrence of osteolytic lesions. The outstanding tribological properties of this bearing system are explained by low surface roughness, high hardness for major scratch resistance, and high wettability. Since the 1970s, technological improvements in the manufacturing process of alumina components together with a better understanding of Morse taper technology have provided a surgical grade material with high density, high purity and small grains. Published studies on the outcome of total hip arthroplasty performed with this new generation of implants showed high survivorship especially in young and active patients, with survival rates free of revision of 90.8% to 97.4% at ten years. However, concern remains over ceramic liner fracture and squeaking, which has been noted recently with increasing prevalence. This review will discuss the current knowledge on the use of alumina-on-alumina bearings. PMID:21191579

  16. Thirty years of experience with alumina-on-alumina bearings in total hip arthroplasty

    PubMed Central

    Zaoui, Amine; Zadegan, Frédéric; Sedel, Laurent; Nizard, Rémy

    2010-01-01

    Alumina-on-alumina bearings in total hip arthroplasty have been developed in an attempt to minimise debris and the occurrence of osteolytic lesions. The outstanding tribological properties of this bearing system are explained by low surface roughness, high hardness for major scratch resistance, and high wettability. Since the 1970s, technological improvements in the manufacturing process of alumina components together with a better understanding of Morse taper technology have provided a surgical grade material with high density, high purity and small grains. Published studies on the outcome of total hip arthroplasty performed with this new generation of implants showed high survivorship especially in young and active patients, with survival rates free of revision of 90.8% to 97.4% at ten years. However, concern remains over ceramic liner fracture and squeaking, which has been noted recently with increasing prevalence. This review will discuss the current knowledge on the use of alumina-on-alumina bearings. PMID:21191579

  17. Medication Adherence Measures: An Overview

    PubMed Central

    Lam, Wai Yin; Fresco, Paula

    2015-01-01

    WHO reported that adherence among patients with chronic diseases averages only 50% in developed countries. This is recognized as a significant public health issue, since medication nonadherence leads to poor health outcomes and increased healthcare costs. Improving medication adherence is, therefore, crucial and revealed on many studies, suggesting interventions can improve medication adherence. One significant aspect of the strategies to improve medication adherence is to understand its magnitude. However, there is a lack of general guidance for researchers and healthcare professionals to choose the appropriate tools that can explore the extent of medication adherence and the reasons behind this problem in order to orchestrate subsequent interventions. This paper reviews both subjective and objective medication adherence measures, including direct measures, those involving secondary database analysis, electronic medication packaging (EMP) devices, pill count, and clinician assessments and self-report. Subjective measures generally provide explanations for patient's nonadherence whereas objective measures contribute to a more precise record of patient's medication-taking behavior. While choosing a suitable approach, researchers and healthcare professionals should balance the reliability and practicality, especially cost effectiveness, for their purpose. Meanwhile, because a perfect measure does not exist, a multimeasure approach seems to be the best solution currently. PMID:26539470

  18. Medication Adherence Measures: An Overview.

    PubMed

    Lam, Wai Yin; Fresco, Paula

    2015-01-01

    WHO reported that adherence among patients with chronic diseases averages only 50% in developed countries. This is recognized as a significant public health issue, since medication nonadherence leads to poor health outcomes and increased healthcare costs. Improving medication adherence is, therefore, crucial and revealed on many studies, suggesting interventions can improve medication adherence. One significant aspect of the strategies to improve medication adherence is to understand its magnitude. However, there is a lack of general guidance for researchers and healthcare professionals to choose the appropriate tools that can explore the extent of medication adherence and the reasons behind this problem in order to orchestrate subsequent interventions. This paper reviews both subjective and objective medication adherence measures, including direct measures, those involving secondary database analysis, electronic medication packaging (EMP) devices, pill count, and clinician assessments and self-report. Subjective measures generally provide explanations for patient's nonadherence whereas objective measures contribute to a more precise record of patient's medication-taking behavior. While choosing a suitable approach, researchers and healthcare professionals should balance the reliability and practicality, especially cost effectiveness, for their purpose. Meanwhile, because a perfect measure does not exist, a multimeasure approach seems to be the best solution currently. PMID:26539470

  19. Study of Mechanical Properties and Fracture Mode of Alumina-Silicon Carbide Nanocomposites

    NASA Astrophysics Data System (ADS)

    Rahimnezhad Yazdi, A.; Baharvandi, H. R.; Abdizadeh, H.; Ehsani, N.

    In this study Al2O3-SiC nanocomposites have been fabricated by mixing of alumina and silicon carbide nano powders, followed by hot pressing at 1700°C. The mechanical properties and fracture mode of Al2O3-SiC nanocomposites containing different volume fractions (5, 10 and 15%) of nano scale SiC particles were investigated and compared with those of alumina. Al2O3-SiC powders were prepared by planetary milling in isopropanol. Fracture mode of specimens was investigated by means of scanning electron microscopy. Nanocomposites were tougher than alumina when they were hot pressed at the same temperature, and the values of nanocomposite's flexural strength and hardness were higher than those of alumina. Flexural strength, hardness and fracture toughness of the nanocomposites increase by increasing the volume percent of SiC up to 10% and then decrease slightly. The Scanning electron microscopy observations showed that fracture mode changes from intergranular for alumina to transgranular for nanocomposites. Finally X-ray diffraction analysis couldn't detect any chemical reactions between Al2O3 and SiC particles.

  20. Enhanced gas separation factors of microporous polymer constrained in the channels of anodic alumina membranes

    NASA Astrophysics Data System (ADS)

    Chernova, Ekaterina; Petukhov, Dmitrii; Boytsova, Olga; Alentiev, Alexander; Budd, Peter; Yampolskii, Yuri; Eliseev, Andrei

    2016-08-01

    New composite membranes based on porous anodic alumina films and polymer of intrinsic microporosity (PIM-1) have been prepared using a spin-coating technique. According to scanning electron microscopy, partial penetration of polymer into the pores of alumina supports takes place giving rise to selective polymeric layers with fiber-like microstructure. Geometric confinement of rigid PIM-1 in the channels of anodic alumina causes reduction of small-scale mobility in polymeric chains. As a result, transport of permanent gases, such as CH4, becomes significantly hindered across composite membranes. Contrary, the transport of condensable gases (CO2, С4H10), did not significantly suffer from the confinement due to high solubility in the polymer matrix. This strategy enables enhancement of selectivity towards CO2 and C4H10 without significant loss of the membrane performance and seems to be prospective for drain and sweetening of natural gas.

  1. Enhanced gas separation factors of microporous polymer constrained in the channels of anodic alumina membranes.

    PubMed

    Chernova, Ekaterina; Petukhov, Dmitrii; Boytsova, Olga; Alentiev, Alexander; Budd, Peter; Yampolskii, Yuri; Eliseev, Andrei

    2016-01-01

    New composite membranes based on porous anodic alumina films and polymer of intrinsic microporosity (PIM-1) have been prepared using a spin-coating technique. According to scanning electron microscopy, partial penetration of polymer into the pores of alumina supports takes place giving rise to selective polymeric layers with fiber-like microstructure. Geometric confinement of rigid PIM-1 in the channels of anodic alumina causes reduction of small-scale mobility in polymeric chains. As a result, transport of permanent gases, such as CH4, becomes significantly hindered across composite membranes. Contrary, the transport of condensable gases (CO2, С4H10), did not significantly suffer from the confinement due to high solubility in the polymer matrix. This strategy enables enhancement of selectivity towards CO2 and C4H10 without significant loss of the membrane performance and seems to be prospective for drain and sweetening of natural gas. PMID:27498607

  2. Enhanced gas separation factors of microporous polymer constrained in the channels of anodic alumina membranes

    PubMed Central

    Chernova, Ekaterina; Petukhov, Dmitrii; Boytsova, Olga; Alentiev, Alexander; Budd, Peter; Yampolskii, Yuri; Eliseev, Andrei

    2016-01-01

    New composite membranes based on porous anodic alumina films and polymer of intrinsic microporosity (PIM-1) have been prepared using a spin-coating technique. According to scanning electron microscopy, partial penetration of polymer into the pores of alumina supports takes place giving rise to selective polymeric layers with fiber-like microstructure. Geometric confinement of rigid PIM-1 in the channels of anodic alumina causes reduction of small-scale mobility in polymeric chains. As a result, transport of permanent gases, such as CH4, becomes significantly hindered across composite membranes. Contrary, the transport of condensable gases (CO2, С4H10), did not significantly suffer from the confinement due to high solubility in the polymer matrix. This strategy enables enhancement of selectivity towards CO2 and C4H10 without significant loss of the membrane performance and seems to be prospective for drain and sweetening of natural gas. PMID:27498607

  3. Active mechanics and geometry of adherent cells and cell colonies

    NASA Astrophysics Data System (ADS)

    Banerjee, Shiladitya

    2014-03-01

    Measurements of traction stresses exerted by adherent cells or cell colonies on elastic substrates have yielded new insight on how the mechanical and geometrical properties of the substrate regulate cellular force distribution, mechanical energy, spreading, morphology or stress ber architecture. We have developed a generic mechanical model of adherent cells as an active contractile gel mechanically coupled to an elastic substrate and to neighboring cells in a tissue. The contractile gel model accurately predicts the distribution of cellular and traction stresses as observed in single cell experiments, and captures the dependence of cell shape, traction stresses and stress ber polarization on the substrate's mechanical and geometrical properties. The model further predicts that the total strain energy of an adherent cell is solely regulated by its spread area, in agreement with recent experiments on micropatterned substrates with controlled geometry. When used to describe the behavior of colonies of adherent epithelial cells, the model demonstrates the crucial role of the mechanical cross-talk between intercellular and extracellular adhesion in regulating traction force distribution. Strong intercellular mechanical coupling organizes traction forces to the colony periphery, whereas weaker intercellular coupling leads to the build up of traction stresses at intercellular junctions. Furthermore, in agreement with experiments on large cohesive keratinocyte colonies, the model predicts a linear scaling of traction forces with the colony size. This scaling suggests the emergence of an effective surface tension as a scale-free material property of the adherent tissue, originating from actomyosin contractility.

  4. Adherence to highly active antiretroviral therapy in Hyderabad, India: barriers, facilitators and identification of target groups.

    PubMed

    Dworkin, Mark S; Douglas, G W; Sabitha Rani, G P; Chakraborty, Apurba

    2016-03-01

    We assessed the barriers and facilitators to highly active antiretroviral therapy adherence and determined their prevalence among HIV/AIDS patients in Hyderabad, India. We conducted a cross-sectional study among HIV-infected adults prescribed highly active antiretroviral therapy and receiving care from nine clinics. Depression was screened using Patient Health Questionnaire 9 and facilitators of HIV medication adherence were assessed using an 11-item scale which yielded a total positive attitude to disease score. Prevalence ratios of non-adherence between different categories of potential risk factors were calculated. We compared mean 'facilitators to adherence' scores between the adherent and non-adherent population. Multivariable Poisson regression with robust variance was used to identify independent risk factors. Among the 211 respondents, nearly 20% were non-adherent, approximately 8% had either moderately severe or severe depression and mean score for combined facilitators to medication adherence was 33.35 (±7.88) out of a possible 44 points. Factors significantly associated with non-adherence included older age, female sex worker, moderate-to-severe depression and the combined facilitators to medication adherence score. These data from a broad range of clinical settings in Hyderabad reveal that key groups to focus on for adherence intervention are female sex workers, older persons and those with depression. PMID:25801316

  5. Self-report measures of medication adherence behavior: recommendations on optimal use.

    PubMed

    Stirratt, Michael J; Dunbar-Jacob, Jacqueline; Crane, Heidi M; Simoni, Jane M; Czajkowski, Susan; Hilliard, Marisa E; Aikens, James E; Hunter, Christine M; Velligan, Dawn I; Huntley, Kristen; Ogedegbe, Gbenga; Rand, Cynthia S; Schron, Eleanor; Nilsen, Wendy J

    2015-12-01

    Medication adherence plays an important role in optimizing the outcomes of many treatment and preventive regimens in chronic illness. Self-report is the most common method for assessing adherence behavior in research and clinical care, but there are questions about its validity and precision. The NIH Adherence Network assembled a panel of adherence research experts working across various chronic illnesses to review self-report medication adherence measures and research on their validity. Self-report medication adherence measures vary substantially in their question phrasing, recall periods, and response items. Self-reports tend to overestimate adherence behavior compared with other assessment methods and generally have high specificity but low sensitivity. Most evidence indicates that self-report adherence measures show moderate correspondence to other adherence measures and can significantly predict clinical outcomes. The quality of self-report adherence measures may be enhanced through efforts to use validated scales, assess the proper construct, improve estimation, facilitate recall, reduce social desirability bias, and employ technologic delivery. Self-report medication adherence measures can provide actionable information despite their limitations. They are preferred when speed, efficiency, and low-cost measures are required, as is often the case in clinical care. PMID:26622919

  6. Adherence in outpatients taking warfarin and its effect on anticoagulation control in Jordan.

    PubMed

    Ababneh, Mera A; Al-Azzam, Sayer I; Alzoubi, Karem H; Rababa'h, Abeer M

    2016-08-01

    Background Medication adherence is an important element for the success of any therapeutic plan. The picture is more complicated with warfarin, due to its small therapeutic window and patients' needs to have effective anticoagulation control. Objective To measure warfarin-adherence, warfarin-knowledge and to assess the relationship between adherence and anticoagulation control. Setting Adult outpatients (≥18 years) taking warfarin at two medical sites in north of Jordan were invited to participate. Method This was a cross sectional study in which survey questionnaire that included demographic, clinical, warfarin related questions and Morisky Medication Adherence Scale (MMAS-8) was administered to patients in Arabic language. International normalization ratio (INR) readings were retrieved from patients' medical records. Main outcome measure MMAS-8 adherence scores and time within therapeutic range were calculated. Results More than half of study participants (54 %) were adherent (MMAS-8 = 8). The MMAS-8 adherence scores were significantly associated with warfarin-knowledge scores (Spearman's ρ = 0.291, p = 0.000). Adherent patients were more likely to have good anticoagulation control compared to non-adherent patients (MMAS-8 ≤ 7). Conclusion Adherence to warfarin therapy can have a substantial effect on anticoagulation control. Thus, healthcare practitioners should consider strategies to improve patient adherence to warfarin. PMID:27015937

  7. The Effect of Excimer Laser Treatment on the Surface Roughness and Fracture Strength of Alumina Substrates

    SciTech Connect

    Smoot, J.E.

    1998-05-13

    The microelectronics industry requires alumina substrates with exceptionally smooth surfaces and few surface defects to allow successful deposition of metallic films for reliable electronic performance. Irradiation by a 248-nm wavelength excimer laser beam (KrF) at a fluence of 125 mJ/mm{sup 2} and at various angles of incidence is shown to significantly reduce the surface roughness of alumina substrates. However, irradiation also creates a fine particulate deposit of alumina that only partially adheres to the substrate and impedes deposition of metal films. Annealing in air between 1350 C and 1450 C was found to remove the particles by sintering. As-received material showed surface roughness average (R{sub a}) mean values of 457 nm, which was reduced to 60 nm (mean) following irradiation and 71 nm (mean) following irradiation and annealing at 1350 C. Irradiation also produced a decrease in the number and severity of surface defects. The flexural strength and Weibull modulus were both increased by laser irradiation and thermal treatment. Flexural strength went from an as-received value of 450 MPa to 560 MPa following irradiation/sintering, measured at 10% probability of failure. The Weibull modulus was increased from the as-received value of about 9, to about 13 following irradiation/sintering. It was concluded that irradiation at an angle of incidence of 60{degree} from perpendicular was most effective in producing a low surface roughness.

  8. Evaluation of Alumina-Forming Austenitic Foil for Advanced Recuperators

    SciTech Connect

    Pint, Bruce A; Brady, Michael P; Yamamoto, Yukinori; Santella, Michael L; Maziasz, Philip J; Matthews, Wendy

    2011-01-01

    A corrosion- and creep-resistant austenitic stainless steel has been developed for advanced recuperator applications. By optimizing the Al and Cr contents, the alloy is fully austenitic for creep strength while allowing the formation of a chemically stable external alumina scale at temperatures up to 900 C. An alumina scale eliminates long-term problems with the formation of volatile Cr oxy-hydroxides in the presence of water vapor in exhaust gas. As a first step in producing foil for primary surface recuperators, three commercially cast heats have been rolled to 100 m thick foil in the laboratory to evaluate performance in creep and oxidation testing. Results from initial creep testing are presented at 675 C and 750 C, showing excellent creep strength compared with other candidate foil materials. Laboratory exposures in humid air at 650 800 C have shown acceptable oxidation resistance. A similar oxidation behavior was observed for sheet specimens of these alloys exposed in a modified 65 kW microturbine for 2871 h. One composition that showed superior creep and oxidation resistance has been selected for the preparation of a commercial batch of foil. DOI: 10.1115/1.4002827

  9. Dielectric Performance of a High Purity HTCC Alumina at High Temperatures - a Comparison Study with Other Polycrystalline Alumina

    NASA Technical Reports Server (NTRS)

    Chen, Liangyu

    2014-01-01

    A very high purity (99.99+%) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this alumina material for co-firing processing. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96% polycrystalline alumina (96% Al2O3), where 96% alumina was used as the benchmark. A prototype packaging system based on regular 96% alumina with Au thickfilm metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500 C. In order to evaluate this new high purity HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96% alumina and a previously tested LTCC alumina from room temperature to 550 C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96% alumina and a selected LTCC alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.

  10. Long-term results of alumina-on-alumina hip arthroplasty for osteonecrosis.

    PubMed

    Nich, Christophe; Sariali, El-Hadi; Sari Ali, El-Hadi; Hannouche, Didier; Nizard, Rémy; Witvoet, Jacques; Sedel, Laurent; Bizot, Pascal

    2003-12-01

    Alumina-on-alumina bearings in THR may, in theory, provide an effective answer to osteolysis in young patients with ON of the femoral head. The purpose of this retrospective study was to report the long-term results of a series of 52 consecutive alumina THAs (41 patients) done for ON. The mean age of the patients at surgery was 41 years (range, 22-79 years). Cemented femoral stems with a 32-mm alumina head were used. Plain alumina cups were used and were either cemented (39 hips) or press-fit (13 hips). No patients were lost to followup. Sixteen hips have been revised. Aseptic loosening of the socket was the main cause of failure. At an average 16-year followup (range, 11-23.65 years), 26 hips were rated excellent and one hip was rated good. No osteolysis was observed and wear was undetectable. If revision for aseptic loosening was the end point, the rate of survival was 88.5% at 10 years for the socket and 100% at 10 years for the stem. With the alumina-on-alumina hip replacement done for ON, absence of osteolysis can be expected for as many as 24 years after the operation. New methods of socket fixation now are being explored. PMID:14646707

  11. Characterization of vitrified ICPP alumina waste calcine

    SciTech Connect

    Cole, H.S.; Brotzman, J.R.; Simpson, G.G.

    1980-08-01

    The properties of one borosilicate and two borophosphate glasses previously developed to vitrify an ICPP alumina nuclear waste calcine are determined. Based on melt viscosity at 1100/sup 0/C and leach rate, the maximum permissible calcine contents in the borophosphate and borosilicate formulations are 26 and 16 mol%, respectively. Glasses containing lesser amounts of calcine do not develop crystalline compounds upon annealing. Based upon the same viscosity and leach rate criteria, 40 wt % CaO or zirconia calcine can be substituted for alumina calcine in the borophosphate glasses. Ten wt % of either additive can be substituted for alumina calcine in the borosilicate glass. Minor modifications of the alkali or cupric oxide content in the borophosphate glasses does not alter glass characteristics.

  12. The challenge of patient adherence.

    PubMed

    Martin, Leslie R; Williams, Summer L; Haskard, Kelly B; Dimatteo, M Robin

    2005-09-01

    Quality healthcare outcomes depend upon patients' adherence to recommended treatment regimens. Patient nonadherence can be a pervasive threat to health and wellbeing and carry an appreciable economic burden as well. In some disease conditions, more than 40% of patients sustain significant risks by misunderstanding, forgetting, or ignoring healthcare advice. While no single intervention strategy can improve the adherence of all patients, decades of research studies agree that successful attempts to improve patient adherence depend upon a set of key factors. These include realistic assessment of patients' knowledge and understanding of the regimen, clear and effective communication between health professionals and their patients, and the nurturance of trust in the therapeutic relationship. Patients must be given the opportunity to tell the story of their unique illness experiences. Knowing the patient as a person allows the health professional to understand elements that are crucial to the patient's adherence: beliefs, attitudes, subjective norms, cultural context, social supports, and emotional health challenges, particularly depression. Physician-patient partnerships are essential when choosing amongst various therapeutic options to maximize adherence. Mutual collaboration fosters greater patient satisfaction, reduces the risks of nonadherence, and improves patients' healthcare outcomes. PMID:18360559

  13. Fourier transform infrared photoacoustic spectroscopy of pyridine adsorbed on silica-alumina and. gamma. -alumina

    SciTech Connect

    Riseman, S.M.; Massoth, F.E.; Dhar, G.M.; Eyring, E.M.

    1982-05-13

    Relative numbers of Bronsted acid to Lewis acid sites on silica-alumina have been determined photoacoustically by an infrared analysis of chemisorbed pyridine compared to similar adsorption of ..gamma..-alumina that has only Lewis sites. Results are similar to those obtained by earlier IR transmission studies that suggested the use of framework vibrations of silica as an internal reference standard. The 20% coverage of the silica-alumina surface by pyridine adsorbed at Bronsted sites found photoacoustically is in good agreement with a previous value of 17% estimated from transmission spectroscopic data. Reproducibility of the photoacoustic measurements is excellent.

  14. Laser Ablation of Alumina in Water

    SciTech Connect

    Musaev, O.; Midgley, A; Wrobel, J; Kruger, M

    2010-01-01

    Bulk {alpha}-alumina immersed in distilled water was ablated by pulsed UV laser radiation. The resulting colloidal solution contained micron and submicron size particles. X-ray diffraction and Raman spectra of the ablated and original material are similar. Hence, most of the ablated material is {alpha}-alumina. From transmission electron microscope images, most of the submicron and all of the micron-sized particles have sharp edges and do not have spherical shapes, indicating that the dominant ablation mechanism is due to crack propagation. Some spherical particles of diameter less than 100 nm are observed, indicating that they were formed from the liquid state.

  15. Chlorination of alumina in kaolinitic clay

    NASA Astrophysics Data System (ADS)

    Grob, B.; Richarz, W.

    1984-09-01

    The chlorination of alumina in kaolinitic clay with Cl2 and CO gas mixtures was studied gravimetrically. The effects of the calcination method and of NaCl addition on the reactivity of the clay were examined. Fast reaction rates were achieved only with samples previously exposed to a sulfating treatment. Optimum conditions, with maximum yield and selectivity to A1C13 and minimum SiO2 conversion, were found between 770 and 970 K. At higher temperatures the SiCl4 formed poisons the reactive alumina surface by selective chemisorption with a marked decrease of the reaction rate.

  16. Nanomechanical humidity detection through porous alumina cantilevers

    PubMed Central

    Klimenko, Alexey; Lebedev, Vasiliy; Lukashin, Alexey; Eliseev, Andrey

    2015-01-01

    Summary We present here the behavior of the resonance frequency of porous anodic alumina cantilever arrays during water vapor adsorption and emphasize their possible use in the micromechanical sensing of humidity levels at least in the range of 10–22%. The sensitivity of porous anodic aluminium oxide cantilevers (Δf/Δm) and the humidity sensitivity equal about 56 Hz/pg and about 100 Hz/%, respectively. The approach presented here for the design of anodic alumina cantilever arrays by the combination of anodic oxidation and photolithography enables easy control over porosity, surface area, geometric and mechanical characteristics of the cantilever arrays for micromechanical sensing. PMID:26199836

  17. Structural transformations in reactively sputtered alumina films

    SciTech Connect

    Nayar, P. Khanna, A.

    2014-04-24

    Thin films of amorphous alumina of thickness ∼350 nm were prepared on silicon wafer by DC cathode reactive sputtering. The effects of thermal annealing on the structural properties were investigated at annealing temperatures of 600°C, 800°C, 1100°C and 1220°C. X-ray diffraction showed that crystallization starts at 800°C and produces δ and θ alumina phases, the latter phase grows with heat treatment and the film was predominantly δ-phase with small amount of a-phase after annealing at 1220°C. AFM studies found that the surface of thin films smoothened upon crystallization.

  18. 40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Siloxane modified alumina... Specific Chemical Substances § 721.10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical... as siloxane modified alumina nanoparticles (PMN P-05-687) is subject to reporting under this...

  19. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Alumina (dried aluminum hydroxide). 73.1010... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white,...

  20. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Alumina (dried aluminum hydroxide). 73.1010... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white,...

  1. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Alumina (dried aluminum hydroxide). 73.1010... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white,...

  2. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Alumina (dried aluminum hydroxide). 73.1010... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white,...

  3. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Alumina (dried aluminum hydroxide). 73.1010... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white,...

  4. 40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Siloxane modified alumina... Specific Chemical Substances § 721.10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical... as siloxane modified alumina nanoparticles (PMN P-05-687) is subject to reporting under this...

  5. 40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Siloxane modified alumina... Specific Chemical Substances § 721.10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical... as siloxane modified alumina nanoparticles (PMN P-05-687) is subject to reporting under this...

  6. REMOVING RADIUM FROM WATER BY PLAIN AND TREATED ACTIVATED ALUMINA

    EPA Science Inventory

    The research determined the feasibility of using BaSO4-impregnated activated alumina and plain activated alumina for radium removal from groundwater by fixed-bed adsorption. The major factors influencing radium adsorption onto the two types of alumina were identified. The radium ...

  7. The effects of water vapor on the oxidation behavior of alumina forming austenitic stainless steels

    DOE PAGESBeta

    Yanar, N. M.; Lutz, B. S.; Garcia-Fresnillo, L.; Brady, Michael P.; Meier, G. H.

    2015-08-19

    The isothermal oxidation behavior of three alumina forming austenitic (AFA) stainless steels with varying composition was studied at 650 and 800 °C in dry air and gases which contained water vapor. The AFA alloys exhibited better oxidation resistance than a “good chromia former” at 650 °C, particularly in H2O-containing atmospheres by virtue of alumina-scale formation. Although the AFA alloys were more resistant than chromia formers, their oxidation resistance was degraded at 650 °C in the presence of water vapor. In dry air the AFA alloys formed, thin continuous alumina scales, whereas in Ar–4%H2–3%H2O the areas of continuous alumina were reducedmore » and Fe oxide-rich nodules and regions of Cr, Mn-rich oxides formed. In some regions internal oxidation of the aluminum occurred in the H2O-containing gas. The alloy OC8 had slightly better resistance than OC4 or OC5 in this atmosphere. The alumina-forming capability of the AFA alloys decreases with increasing temperature and, at 800 °C, they are borderline alumina formers, even in dry air. The oxidation resistance of all three alloys was degraded at 800 °C in atmospheres, which contained water vapor (Air–10%H2O, Ar–3%H2O and Ar–4%H2–3%H2O). The areas, which formed continuous alumina, were reduced in these atmospheres and areas of internal oxidation occurred. However, as a result of the borderline alumina-forming capability of the AFA alloys it was not possible to determine which of the H2O-containing atmospheres was more severe or to rank the alloys in terms of their performance. The experimental results indicate that the initial microstructure of the AFA alloys also plays a role in their oxidation performance. Less protective oxides formed at 800 °C when alloy OC8 was equilibrated before exposure rather than being exposed in the as-processed condition. As a result, the reason for this is the presence of different phases in the bulk of the two specimens.« less

  8. The effects of water vapor on the oxidation behavior of alumina forming austenitic stainless steels

    SciTech Connect

    Yanar, N. M.; Lutz, B. S.; Garcia-Fresnillo, L.; Brady, Michael P.; Meier, G. H.

    2015-08-19

    The isothermal oxidation behavior of three alumina forming austenitic (AFA) stainless steels with varying composition was studied at 650 and 800 °C in dry air and gases which contained water vapor. The AFA alloys exhibited better oxidation resistance than a “good chromia former” at 650 °C, particularly in H2O-containing atmospheres by virtue of alumina-scale formation. Although the AFA alloys were more resistant than chromia formers, their oxidation resistance was degraded at 650 °C in the presence of water vapor. In dry air the AFA alloys formed, thin continuous alumina scales, whereas in Ar–4%H2–3%H2O the areas of continuous alumina were reduced and Fe oxide-rich nodules and regions of Cr, Mn-rich oxides formed. In some regions internal oxidation of the aluminum occurred in the H2O-containing gas. The alloy OC8 had slightly better resistance than OC4 or OC5 in this atmosphere. The alumina-forming capability of the AFA alloys decreases with increasing temperature and, at 800 °C, they are borderline alumina formers, even in dry air. The oxidation resistance of all three alloys was degraded at 800 °C in atmospheres, which contained water vapor (Air–10%H2O, Ar–3%H2O and Ar–4%H2–3%H2O). The areas, which formed continuous alumina, were reduced in these atmospheres and areas of internal oxidation occurred. However, as a result of the borderline alumina-forming capability of the AFA alloys it was not possible to determine which of the H2O-containing atmospheres was more severe or to rank the alloys in terms of their performance. The experimental results indicate that the initial microstructure of the AFA alloys also plays a role in their oxidation performance. Less protective oxides formed at 800 °C when alloy OC8 was equilibrated before exposure rather than being exposed in the as-processed condition. As a result, the reason for this is the presence of different

  9. Adherence of sputtered titanium carbides

    NASA Technical Reports Server (NTRS)

    Brainard, W. A.; Wheeler, D. R.

    1979-01-01

    Sputtered coatings of the refractory metal carbides are of great interest for applications where hard wear-resistant materials are desired. The usefulness of sputtered refractory carbides is often limited, in practice, by spalling or interfacial separation. In this work improvements in the adherence of refractory carbides on iron, nickel and titanium based alloys were obtained by using oxidation, reactive sputtering or sputtered interlayers to alter the coating-substrate interfacial region. X-ray photoelectron spectroscopy and argon ion etching were used to characterize the interfacial regions, and an attempt was made to correlate adherence as measured in wear tests with the chemical nature of the interface.

  10. Dielectric breakdown of polycrystalline alumina: A weakest-link failure analysis

    NASA Astrophysics Data System (ADS)

    Block, Benjamin

    The effects of varying electrode geometry (ball and ring) and size (radius), dielectric media (castor oil and DialaRTM oil), specimen thickness, and concentration of defects on the dielectric breakdown strength of commercial-grade alumina and high-purity fine-grained (HPFG) alumina were investigated. The breakdown strength was expressed in terms of the maximum electric field in the ceramic at the breakdown voltage calculated by finite element analysis (FEA). The breakdown strength decreased systematically with increasing electrode radius and specimen thickness. The breakdown strength increased with decreasing concentration of defects. The breakdown strength was higher in the Diala RTM oil (dielectric constant, epsilonr = 2.3 +/- 0.12) as compared to the castor oil (epsilonr = 4.59 +/- 0.06). The breakdown strength was higher for the HPFG alumina as compared to the commercial- grade alumina. These effects of the electrode geometry, specimen thickness, concentration of defects, and of the dielectric media were analyzed with a weakest-link failure model employing the Laplace and Weibull distributions for a population of defects in the material. The measured size or scaling effects of the electrodes, specimen thickness, concentration of defects, and of the liquid media on breakdown strength were in better agreement with the Laplace distribution for the population. The measured concentration of surface defects was in good agreement with the concentration of surface defects estimated from the surface area scaling of the breakdown field with the Laplace distribution.

  11. Factors Influencing Adherence to Imatinib in Indian Chronic Myeloid Leukemia Patients: A Cross-Sectional Study

    PubMed Central

    Kapoor, Jyotsna; Agrawal, Narendra; Ahmed, Rayaz; Sharma, Sanjeev Kumar; Gupta, Anshul; Bhurani, Dinesh

    2015-01-01

    Adherence to imatinib(IM) is of utmost importance in patients with chronic myeloid leukemia (CML) to maximise treatment effectiveness. The main objective is to measure adherence to IM by evaluating individual patient characteristics, personal behaviour and, treatment related psychological factors influencing adherence behaviour. Hundred patients receiving IM were analysed for adherence behaviour using 9 item Morisky Medication Adherence Scale (9-MMAS). Various factors were assessed for their impact on adherence behaviour. These factors were age, gender, duration of treatment, frequency and dosing of treatment, use of tobacco and alcohol, educational qualification, employment status, monthly income, side effects, financial assistance in treatment, social support, knowledge about medicine and disease, concomitant drug burden, polypharmacy, physician patient interaction, patient educational sessions and prevalence of depression. Seventy five percent of patients were found to be adherent. On univariate analysis, prevalence of depression (p<0.000001), moderate severe depression (p<0.000001), concomitant drug burden (p=0.036) and monthly income (p=0.015) were found to be significantly influencing adherence. The final multivariate model retained prevalence of depression with OR= 10.367 (95% CI, 3.112–34.538) as independent predictor of adherence to therapy. This study suggests that identification and treatment of depression among CML patients may further enhance adherence to IM therapy. PMID:25745540

  12. Cultural influences on antiretroviral therapy adherence among HIV-infected Puerto Ricans.

    PubMed

    Robbins, Reuben N; D'Aquila, Erica; Morgello, Susan; Byrd, Desiree; Remien, Robert H; Mindt, Monica Rivera

    2012-01-01

    Adherence to antiretroviral therapy (ART) is integral to the successful treatment of HIV infection. Research has indicated that HIV-infected Latinos may have difficulty adhering to ART. While studies have demonstrated strong relationships between numerous psychosocial factors and ART adherence, no research has examined if cultural factors are also involved in ART adherence among Latinos. Our study examined the relationship between acculturation to mainstream U.S. culture, bicultural self-efficacy, and ART adherence among HIV-infected Puerto Rican adults living in the United States. Participants with ≥ 95% adherence scored higher on U.S.- and Latino-involvement acculturation scales and on a measure of bicultural self-efficacy compared to those with suboptimal adherence. Among bicultural HIV-infected Puerto Ricans, both acculturation and self-efficacy to navigate between cultures were positively related to adherence. Understanding the role of an individual's sociocultural experience may help elucidate why HIV-infected Latinos have difficulties achieving optimal ART adherence and improve ART adherence interventions. PMID:22525858

  13. Suboptimal inhaler medication adherence and incorrect technique are common among chronic obstructive pulmonary disease patients.

    PubMed

    Sriram, Krishna B; Percival, Matthew

    2016-02-01

    Patients with chronic obstructive pulmonary disease (COPD) are routinely prescribed one or more inhaled medications. Adherence to inhaler medications and correct inhaler device technique are crucial to successful COPD management. The goals of this study were to estimate adherence and inhaler technique in a cohort of COPD patients. This was an observational study conducted on a sample of 150 COPD patients. Medication adherence was assessed using the Medication Adherence Report Scale (MARS). Inhaler technique was assessed using standardized checklists. Clinical data were collected using a proforma. Of the 150 patients (mean age 70.3 years, 52% male), 58% reported suboptimal adherence (MARS ≤ 24). High adherence to therapy (MARS = 25) was associated with older age (p = 0.001), but not any of the other studied variables. Medication non-adherence was not associated with COPD exacerbations. Errors (≥ 1) in inhaler technique were common across all of the types of inhaler devices reportedly used by patients, with the highest proportion of errors among Turbuhaler users (83%) and the least proportion of errors among Handihaler users (50%). No clinical variables were associated with errors in inhaler technique. Suboptimal adherence and errors in inhaler technique are common among COPD patients. No clinical variables to assist in the prediction of medication non-adherence and poor inhaler technique were identifiable. Consequently, regular assessment of medication adherence and inhaler technique should be incorporated into routine clinical practice to facilitate improved health outcomes among patients with COPD. PMID:26396159

  14. Factors influencing illness representations and perceived adherence in haemophilic patients: a pilot study.

    PubMed

    Lamiani, G; Strada, I; Mancuso, M E; Coppola, A; Vegni, E; Moja, E A

    2015-09-01

    Illness representations of chronic patients are important to explain adherence and preventive behaviours. However, it is unclear if the patient's objective health status may influence illness representations and perceived adherence. This study explored if health status and socio-demographic characteristics influence illness representations and perceived adherence in haemophilic patients. Fifty patients (25 on-demand and 25 on prophylaxis) ageing from 13-73, completed the Illness Perceptions Questionnaire-Revised and the Morisky Medication Adherence Scale. Patients' cognitive illness representations were influenced by type of treatment, haemophilia severity, presence of inhibitor and co-morbidity. Perceived chronicity was influenced by patient's age (P = 0.021). Perceived adherence was not influenced by the health status, but was affected by the relationship status (P = 0.048). Perceived adherence was predicted by perceived chronicity (β = 0.412; P = 0.003) and by emotions (β = -0.308; P = 0.023). Patient's health status seems to affect cognitive illness representations but not perceived adherence. Perceived chronicity and negative emotions, which affected perceived adherence, were not influenced by the health status. Physician-patient communication addressing perceived chronicity and emotions rather than patients' health status may influence patient's adherence. Psycho-educational groups could be offered to promote patient's well-being and adjustment to haemophilia, and improve adherence. PMID:25684356

  15. Method of making nanocrystalline alpha alumina

    DOEpatents

    Siegel, Richard W.; Hahn, Horst; Eastman, Jeffrey A.

    1992-01-01

    Method of making selected phases of nanocrystalline ceramic materials. Various methods of controlling the production of nanocrystalline alpha alumina and titanium oxygen phases are described. Control of the gas atmosphere and use of particular oxidation treatments give rise to the ability to control the particular phases provided in the aluminum/oxygen and titanium/oxygen system.

  16. Scales

    MedlinePlus

    Scales are a visible peeling or flaking of outer skin layers. These layers are called the stratum ... Scales may be caused by dry skin, certain inflammatory skin conditions, or infections. Eczema , ringworm , and psoriasis ...

  17. Thermal Conductivity of Alumina-Toughened Zirconia Composites

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.; Zhu, Dong-Ming

    2003-01-01

    10-mol% yttria-stabilized zirconia (10YSZ)-alumina composites containing 0 to 30 mol% alumina were fabricated by hot pressing at 1500 C in vacuum. Thermal conductivity of the composites, determined at various temperatures using a steady-state laser heat flux technique, increased with increase in alumina content. Composites containing 0, 5, and 10-mol% alumina did not show any change in thermal conductivity with temperature. However, those containing 20 and 30-mol% alumina showed a decrease in thermal conductivity with increase in temperature. The measured values of thermal conductivity were in good agreement with those calculated from simple rule of mixtures.

  18. Therapist Adherence to Good Psychiatric Practice in a Short-Term Treatment for Borderline Personality Disorder.

    PubMed

    Kolly, Stéphane; Despland, Jean-Nicolas; de Roten, Yves; Marquet, Pierre; Kramer, Ueli

    2016-07-01

    Therapist adherence describes the quality of interventions according to the imperatives of a treatment model. We examined the relationship between therapist adherence and symptom change in the context of a short-term treatment with respect good psychiatric management (GPM) principles. Based on a parent trial, borderline personality disorder patients (N = 40) benefited from a 10-session intervention. Adherence to GPM was assessed using a GPM Adherence Scale (GPMAS). The psychometric properties of the GPMAS were excellent, and the adherence to GPM explained 16% of the general symptom improvement (t(1) = 2.38, β = 0.40, p = 0.02) and 23% of the borderline symptom improvement (t(1) = 2.46, β = 0.48, p = 0.02). Because GPM adherence predicts the outcome after only 10 sessions, GPMAS is a valuable measure early on in psychiatric practice as part of an initial step to longer-term treatment, to quickly detect problems and correct them. PMID:27187770

  19. Improving Patient's Primary Medication Adherence

    PubMed Central

    Leguelinel-Blache, Géraldine; Dubois, Florent; Bouvet, Sophie; Roux-Marson, Clarisse; Arnaud, Fabrice; Castelli, Christel; Ray, Valérie; Kinowski, Jean-Marie; Sotto, Albert

    2015-01-01

    Abstract Quality of transitions of care is one of the first concerns in patient safety. Redesigning the discharge process to incorporate clinical pharmacy activities could reduce the incidence of postdischarge adverse events by improving medication adherence. The present study investigated the value of pharmacist counseling sessions on primary medication adherence after hospital discharge. This study was conducted in a 1844-bed hospital in France. It was divided in an observational period and an interventional period of 3 months each. In both periods, ward-based clinical pharmacists performed medication reconciliation and inpatient follow-up. In interventional period, initial counseling and discharge counseling sessions were added to pharmaceutical care. The primary medication adherence was assessed by calling community pharmacists 7 days after patient discharge. We compared the measure of adherence between the patients from the observational period (n = 201) and the interventional period (n = 193). The rate of patients who were adherent increased from 51.0% to 66.7% between both periods (P < 0.01). When discharge counseling was performed (n = 78), this rate rose to 79.7% (P < 0.001). The multivariate regression performed on data from both periods showed that age of at least 78 years old, and 3 or less new medications on discharge order were predictive factors of adherence. New medications ordered at discharge represented 42.0% (n = 1018/2426) of all medications on discharge order. The rate of unfilled new medications decreased from 50.2% in the observational period to 32.5% in the interventional period (P < 10−7). However, patients included in the observational period were not significantly more often readmitted or visited the emergency department than the patients who experienced discharge counseling during the interventional period (45.3% vs. 46.2%; P = 0.89). This study highlights that discharge counseling sessions are

  20. Dielectric Performance of High Purity HTCC Alumina at High Temperatures - A Comparison Study with Other Polycrystalline Alumina

    NASA Technical Reports Server (NTRS)

    Chen, Liang-Yu

    2012-01-01

    A very high purity (99.99+) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this co-fired material. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96 polycrystalline alumina (96 Al2O3), where 96 alumina was used as the benchmark. A prototype packaging system based on regular 96 alumina with Au thick-film metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500C. In order to evaluate this new HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96 alumina and a LTCC alumina from room temperature to 550C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96 alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.

  1. Study of alumina-trichite reinforcement of a nickel-based matric by means of powder metallurgy

    NASA Technical Reports Server (NTRS)

    Walder, A.; Hivert, A.

    1982-01-01

    Research was conducted on reinforcing nickel based matrices with alumina trichites by using powder metallurgy. Alumina trichites previously coated with nickel are magnetically aligned. The felt obtained is then sintered under a light pressure at a temperature just below the melting point of nickel. The halogenated atmosphere technique makes it possible to incorporate a large number of additive elements such as chromium, titanium, zirconium, tantalum, niobium, aluminum, etc. It does not appear that going from laboratory scale to a semi-industrial scale in production would create any major problems.

  2. Adherence and Treatment Satisfaction in Liver Transplant Recipients

    PubMed Central

    Albekairy, Abdulkareem M.; Alkatheri, Abdulmalik M.; Jarab, Anan; Khalidi, Nabil; Althiab, Khalifah; Alshaya, Abdulrahman; Saleh, Khalid Bin; Ismail, Wesam W.; Qandil, Amjad M.

    2016-01-01

    Background/Aims: Liver transplantation (LT) is a life-saving intervention for patients with liver failure. LT recipients' adherence to their therapeutic regimen is an essential element for graft survival. According to WHO, the impact of medication non-adherence in solid organ transplantation has shown to cost $15–100 million annually. The aim of the present study was to identify the factors that best predict medication adherence and to explore the relationship between treatment satisfaction and medication adherence in liver transplant recipients. Patients and Methods: Adult liver transplant patients at King Abdulaziz Medical City were included in the study. Patients completed the 8-item Morisky Medication Adherence Scale (MMAS-8) and the Treatment Satisfaction Questionnaire for Medication (TSQM 1.4) in addition to several socio-demographic and transplant-related data. Results: A total of 154 patients were included in the study and of these 59.7% were adherent. Older age was a significant predictor of adherence (P < 0.05). The mean treatment satisfaction score was 91.9 ± 12.7 in Effectiveness, 80.0 ± 25.9 in Side Effects, 83.5 ± 15.7 in Convenience, and 94.6 ± 8.6 in Global Satisfaction. Further analysis indicated that patients in the adherent group had reported significantly higher satisfaction scores than those in the non-adherent group (P < 0.05) in all treatment satisfaction domains: Effectiveness (94.4 ± 10.4 vs. 88.6 ± 14.8), Side Effects (83.9 ± 22.0 vs. 74.2 ± 30.1), Convenience (87.0 ± 13.9 vs. 77.2 ± 16.1), and Global Satisfaction (96.9 ± 6.6 vs. 91.2 ± 8.6). Conclusion: Older patients and those who were more satisfied with their treatment tend to have better adherence to the prescribed medications. Therefore, increasing patients' satisfaction with their treatment should be an integral element of future care plans designed to improve treatment outcomes in liver transplant recipients. PMID:26997219

  3. Association between adherence, treatment satisfaction and illness perception in hypertensive patients.

    PubMed

    Saarti, S; Hajj, A; Karam, L; Jabbour, H; Sarkis, A; El Osta, N; Rabbaa Khabbaz, L

    2016-05-01

    The relationship between adherence to antihypertension medications, treatment satisfaction and illness perception has not been studied so far. The primary objective of this study was to examine the association between adherence to medication, treatment satisfaction and illness perception in Lebanese hypertensive patients. The relation between medication adherence and blood pressure (BP) control was also assessed. In this cross-sectional study, patients were recruited from the physician's practice offices and community pharmacies in Beirut. Patients who had been treated for hypertension for at least 3 months were invited to participate in the study; they completed three questionnaires: the 8-item Morisky Medication Adherence Scale (MMAS-8), the Treatment Satisfaction Questionnaire for Medication (TSQM-4) and the Brief Illness Perception Questionnaire (BIPQ). BP was also measured and recorded. A total of 117 subjects were included, of whom 29.1% had poor adherence to their antihypertension treatment (MMAS-8 scores<6). The odds of having well-controlled hypertension was 3.5 times higher in patients with high adherence compared with patients with poor adherence (P=0.010). Treatment satisfaction was significantly greater in patients with good adherence (P<0.001). Neither socio-demographic, disease- nor drug-related characteristics of the participants were significantly associated with medication adherence. As for illness perception, even though the mean BIPQ score of adherent participants was lower than the mean score of non-adherent participants, this difference did not reach statistical significance. In conclusion, treatment satisfaction was found to be a predictor of adherence. Studies are needed to determine whether interventions to increase satisfaction can improve adherence and BP control. PMID:26310182

  4. Adherence to prescribed medications of Iranian traditional medicine in a group of patients with chronic disease

    PubMed Central

    Dabaghian, Fataneh Hashem; Rassouli, Maryam; Sadighi, Jila; Ghods, Roshanak

    2016-01-01

    Objective: The extent to which a person's health-related behavior corresponds with medical instructions (adherence) is an important modifier of health system effectiveness. This study was designed to determine the patients’ adherence to Iranian traditional medicine in a group of patients with chronic disease. Methods: Convenience sampling was used to enroll 320 patients with chronic diseases from January 2014 to January 2015 in clinics of traditional medicine affiliated with medical universities in Tehran. Morisky Medication Adherence Scale (MMAS) was used to measure the adherence. After describing the variables and the frequency of adherence, logistic regression analysis was used to determine the influencing factors. Findings: Mean age was 40.8 (standard deviation [SD] =13) years. The mean of the duration of disease was 54.6 (SD = 56.1) months and mean of the duration of referring to the clinics 6.5 (SD = 6.9) months. Total score of MMAS was zero in 33 (10.3%) of patients (high adherence), one or two in 128 (40%) of patients (moderate adherence), and more than two in 159 (49.7%) of patients (low adherence). Forgetfulness, bad taste, not availability, and the high cost of the drugs were the most commonly reported causes of non-adherence. Adherence was associated with age (odds ratio [OR] =1.05, 95% confidence interval [95% CI] 1–1.1), marriage (OR = 10.8, 95% CI 2.05–57.6), number of prescribed drugs (OR = 0.05, 95% CI 0.02–0.14), and duration of disease (OR = 1.01, 95% CI 1–1.02). Conclusion: Considering the low adherence in users of medications of Iranian traditional medicine, health care practitioners need to be trained in adherence and the influencing factors and also to use some interventions to increase the adherence. PMID:26985436

  5. Adherence with Electronic Monitoring and Symptoms in Children with Attention Deficit Hyperactivity Disorder

    PubMed Central

    Yang, Jaewon; Yoon, Byung-Moon; Lee, Moon-Soo; Joe, Sook-Haeng; Jung, In-Kwa

    2012-01-01

    Objective The primary aim of this study was to compare electronic monitoring with other measures of adherence to Osmotic-controlled Release Oral delivery System methylphenidate in children with attention-deficit hyperactivity disorder (ADHD). The secondary aim was to analyze the relationships between adherence and clinical factors, including ADHD symptoms. Methods Thirty-nine children diagnosed with ADHD were monitored for adherence to medication over the course of eight weeks. Medication adherence was assessed using the Medication Event Monitoring System (MEMS), which is a bottle cap with a microprocessor that records all instances and times that the bottle is opened; patient self-report; clinician rating; and pill count. Information, including demographic and clinical characteristics, symptom rating scale, and psychological test results, were also collected. The relationships between adherence and clinical factors, including ADHD rating scores of baseline and of the changes, were assessed. Results The rate of non-adherence measured by the MEMS was found to be 46.2%, which was considerably higher than those of the patient self-report (17.9%), clinician rating (31.7%), and pill count (12.8%) of non-adherence. The rate of adherence measured by the MEMS was not significantly associated with baseline symptom severity or symptom changes over the eight weeks, although non-adherent group showed more severe baseline symptoms and inferior improvement. Conclusion Adherence as measured by the MEMS showed a discrepancy with other measures of adherence in patients with ADHD. The symptom severity and level of improvement were not related to adherence with MEMS. Further studies are needed to evaluate the variables that may impact medication adherence in children with ADHD. PMID:22993526

  6. Alumina-on-alumina total hip prostheses in patients 40 years of age or younger.

    PubMed

    Bizot, P; Banallec, L; Sedel, L; Nizard, R

    2000-10-01

    To avoid the consequences of polyethylene wear in a high-risk population, 128 alumina-on-alumina total hip arthroplasties have been done in 104 consecutive patients. The maximum age of patients was 40 years. The main preoperative diagnoses were osteonecrosis and sequellae of congenital hip dislocation (71% of the hips). The same titanium alloy cemented stem was implanted in all of the hips. Four types of alumina acetabular component fixations were used: a cemented plain alumina socket (41 hips), a screw-in ring with an alumina insert (22 hips), a press-fit plain alumina socket (32 hips), and a press-fit titanium metal back with an alumina insert (33 hips). Eight patients (11 hips) died during the followup period. Sixteen revisions have been documented, 12 for acetabular aseptic loosening, three for bipolar loosening (two of which were septic), and one for unexplained pain. Eighty-eight hips in 74 patients have been followed up radiologically for 2 to 22 years. Wear was unmeasurable. Four additional sockets showed definite migration. The respective survival rates after 7 years were 94.1% for the cemented cup, 88.8% for the screw-in ring, 95.1% for cementless press-fit plain alumina socket and 94.3% for the metal-back press-fit component. The 10-year survival rate was 90.4% for the cemented socket and 88.8% for the screw-in ring. The 15-year survival rate was 78.9% for the cemented socket. Grafting was the only prognostic factor, with a survival rate of 62.6% after 10 years for the hips with a bone graft and of 90.1% for hips without a graft. The alumina-on-alumina bearing surfaces seem to be a valuable alternative to the standard metal-on-polyethylene system for young patients. However, an improvement in socket fixation is required to lengthen the life span of the prosthesis to match the life expectancy of this demanding population. PMID:11039794

  7. The effects of psychological factors in sports medicine rehabilitation adherence.

    PubMed

    Lampton, C C; Lambert, M E; Yost, R

    1993-09-01

    This study investigated the influence of achievement motivation and self-esteem on injury treatment adherence in a general sample of injured patients receiving treatment in a sports medicine clinic. Subjects consisted of both injured athletes and workers who had incurred an on-the-job injury. Based on scales of self-esteem and achievement motivation, patients were categorized as either high or low in self-esteem certainty, self-esteem level, tendency to be task-involved, and tendency to ego-involved in tasks. Treatment adherence was measured by number of missed appointments and by physical therapist ratings of effort and progress. It was found that patients low in self-esteem certainty and high in ego-involvement tended to miss the most treatment appointments. Contrary to previous findings, task-involvement was not found to be related to treatment adherence. PMID:8107483

  8. Improving medication adherence in migraine treatment.

    PubMed

    Seng, Elizabeth K; Rains, Jeanetta A; Nicholson, Robert A; Lipton, Richard B

    2015-06-01

    Medication adherence is integral to successful treatment of migraine and other headache. The existing literature examining medication adherence in migraine is small, and the methodologies used to assess adherence are limited. However, these studies broadly suggest poor adherence to both acute and preventive migraine medications, with studies using more objective monitoring reporting lower adherence rates. Methods for improving medication adherence are described, including organizational strategies, provider-monitoring and self-monitoring of adherence, regimen strategies, patient education, self-management skills training (e.g., stimulus control, behavioral contracts), and cognitive-behavioral therapy techniques. The article concludes by discussing the future of research regarding adherence to medications for migraine and other headaches. PMID:26040703

  9. Factors influencing human leukocyte adherence in vitro.

    PubMed

    Stepniewicz, W; Tchórzewski, H; Luciak, M

    1983-01-01

    Studies were performed on factors influencing leucocyte adherence in vitro. Blood condensation was found to increase leukocyte adherence. Addition of heparin, dextran or ethanol caused a significant reduction of white blood cell count in blood samples in comparison with blood mixed with sodium EDTA or ACD solution. This suggests the existence of two granulocyte subpopulations; viz, rapidly adhering and slowly adhering. Heparin enhanced granulocyte adherence, while dextran and ethanol decreased it. Five-day storage of ACD blood led to a decrease in granulocyte adherence, while addition of heparin or histamine to ACD blood prevented this change to occur. The glucose concentration of 1,000 mg/dl augmented granulocyte adherence, while higher glucose concentrations induced its progressive fall below the control values. There was no significant change of lymphocyte adherence during the experiments. PMID:6194070

  10. Rheological Properties of Aqueous Nanometric Alumina Suspensions

    SciTech Connect

    Chuanping Li

    2004-12-19

    Colloidal processing is an effective and reliable approach in the fabrication of the advanced ceramic products. Successful colloidal processing of fine ceramic powders requires accurate control of the rheological properties. The accurate control relies on the understanding the influences of various colloidal parameters on the rheological properties. Almost all research done on the rheology paid less attention to the interactions of particle and solvent. However, the interactions of the particles are usually built up through the media in which the particles are suspended. Therefore, interactions of the particle with the media, the adsorbed layers on the particle surface, and chemical and physical properties of media themselves must influence the rheology of the suspension, especially for the dense suspensions containing nanosized particles. Relatively little research work has been reported in this area. This thesis addresses the rheological properties of nanometric alumina aqueous suspensions, and paying more attention to the interactions between particle and solvent, which in turn influence the particle-particle interactions. Dense nanometric alumina aqueous suspensions with low viscosity were achieved by environmentally-benign fructose additives. The rheology of nanometric alumina aqueous suspensions and its variation with the particle volume fraction and concentration of fructose were explored by rheometry. The adsorptions of solute (fructose) and solvent (water) on the nanometric alumina particle surfaces were measured and analyzed by TG/DSC, TOC, and NMR techniques. The mobility of water molecules in the suspensions and its variation with particle volume fractions and fructose additive were determined by the {sup 17}O NMR relaxation method. The interactions between the nanometric alumina particles in water and fructose solutions were investigated by AFM. The results indicated that a large number of water layers were physically bound on the particles' surfaces

  11. Adherence issues related to sublingual immunotherapy as perceived by allergists

    PubMed Central

    Scurati, Silvia; Frati, Franco; Passalacqua, Gianni; Puccinelli, Paola; Hilaire, Cecile; Incorvaia, Cristoforo

    2010-01-01

    Objectives: Sublingual immunotherapy (SLIT) is a viable alternative to subcutaneous immunotherapy to treat allergic rhinitis and asthma, and is widely used in clinical practice in many European countries. The clinical efficacy of SLIT has been established in a number of clinical trials and meta-analyses. However, because SLIT is self-administered by patients without medical supervision, the degree of patient adherence with treatment is still a concern. The objective of this study was to evaluate the perception by allergists of issues related to SLIT adherence. Methods: We performed a questionnaire-based survey of 296 Italian allergists, based on the adherence issues known from previous studies. The perception of importance of each item was assessed by a VAS scale ranging from 0 to 10. Results: Patient perception of clinical efficacy was considered the most important factor (ranked 1 by 54% of allergists), followed by the possibility of reimbursement (ranked 1 by 34%), and by the absence of side effects (ranked 1 by 21%). Patient education, regular follow-up, and ease of use of SLIT were ranked first by less than 20% of allergists. Conclusion: These findings indicate that clinical efficacy, cost, and side effects are perceived as the major issues influencing patient adherence to SLIT, and that further improvement of adherence is likely to be achieved by improving the patient information provided by prescribers. PMID:20622914

  12. Stability domain of alumina thermally grown on Fe-Cr-Al-based model alloys and modified surface layers exposed to oxygen-containing molten Pb

    NASA Astrophysics Data System (ADS)

    Jianu, A.; Fetzer, R.; Weisenburger, A.; Doyle, S.; Bruns, M.; Heinzel, A.; Hosemann, P.; Mueller, G.

    2016-03-01

    The paper gives experimental results concerning the morphology, composition, structure and thickness of the oxide scales grown on Fe-Cr-Al-based bulk alloys during exposure to oxygen-containing molten lead. The results are discussed and compared with former results obtained on Al-containing surface layers, modified by melting with intense pulsed electron beam and exposed to similar conditions. The present and previous results provide the alumina stability domain and also the criterion of the Al/Cr ratio for the formation of a highly protective alumina layer on the surface of Fe-Cr-Al-based alloys and on modified surface layers exposed to molten lead with 10-6 wt.% oxygen at 400-600 °C. The protective oxide scales, grown on alumina-forming Fe-Cr-Al alloys under the given experimental conditions, were transient aluminas, namely, kappa-Al2O3 and theta-Al2O3.

  13. Enhancing Adherence in Clinical Exercise Trials.

    ERIC Educational Resources Information Center

    O'Neal, Heather A.; Blair, Steven N.

    2001-01-01

    Discusses exercise adherence from the perspective of adhering to an exercise treatment in a controlled trial, focusing on: adherence (to intervention and measurement); the development of randomized clinical trials; exemplary randomized clinical trials in exercise science (exercise training studies and physical activity interventions); and study…

  14. Cementless bulk alumina socket: preliminary results at 6 years.

    PubMed

    Hamadouche, M; Nizard, R S; Meunier, A; Bizot, P; Sedel, L

    1999-09-01

    To avoid polyethylene wear observed in total hip replacement, an alumina-alumina combination has been used since 1977. The aim of this study is to report the results of a hybrid alumina-alumina total hip arthroplasty with a cementless press-fit bulk alumina socket and a cemented titanium alloy stem in 55 patients (62 hips) operated on between 1982 and 1990. The bearing surfaces were a 32-mm alumina head articulating within the alumina socket. Four failures occurred: 3 aseptic loosenings of the socket and 1 femoral head fracture. Considering aseptic loosening as the endpoint, the survival rate was 93.2% after 6 years. At a mean of 72.1 months' follow-up, 92.4% of the surviving hips were graded as very good or good using the Merle d'Aubigné-Postel hip score. Radiolucent lines were observed on the acetabular side in 68.1 of the hips. The future of this interface, which is probably fibrous, remains questionable. With the exception of 1 femoral head fracture, all revisions were related to failure of the bony fixation of the socket, and no problem was encountered related to the alumina-alumina friction coupling. Alumina sockets with other types of cementless fixation have therefore been designed and are presently under clinical investigation. PMID:10512442

  15. How can we improve adherence?

    PubMed

    Price, Patricia

    2016-01-01

    Many patients with wound healing difficulties are also coping with the management of a chronic disease or chronic condition that requires them to make lifestyle behaviour changes, for example, managing glucose levels through diet and exercise and regular foot inspection. Many find it difficult to make such changes and often experience feelings of powerlessness when faced with a lifetime of behavioural and psychological change. This article will explore the importance of understanding the patient difficulties associated with adherence to a regime and how life changes can be difficult to maintain over sustained periods of time. However, the article will also discuss the importance of this topic in trying to understand the clinical evidence base for treatment--as many clinical trials investigating treatments for the diabetic foot do not include information on the extent to which patients in the trial conformed to the trial protocol. The article gives an overview of recent developments--including lessons we can learn from other chronic conditions where permanent life changes are required--in particular the need to keep health messages simple, tailored to the individual and repeated frequently. The evidence to date suggests that no one single form of adherence intervention will work with all patients; this is not surprising given complex and multifactorial nature of adherence and the myriad of barriers that exist that patients and health care professionals need to overcome. PMID:26453542

  16. Elastohydrodynamics of contact in adherent sheets

    NASA Astrophysics Data System (ADS)

    Carlson, Andreas; Mandre, Shreyas; Mahadevan, L.

    2015-11-01

    The dynamics of contact between a thin elastic film and a solid arises in many scientific and engineering applications, from the simple saran-wrap to cellular adhesion to grounding lines in ice sheets. Here, we use a mathematical description of the multi-scale processes associated with microscopic adhesion, fluid flow and elastic thin film deformation to deduce the dynamics of the onset of adhesion, as well as the speed and the shape of the adhesion zone. Our analysis is consistent with prior experimental observations, provides new testable predictions for the shape, size and dynamics of adherent contact in thin sheets and in addition provides a broadly applicable prescription for the boundary conditions at elastic contact lines.

  17. Li + ion diffusion in nanoscale alumina coatings

    NASA Astrophysics Data System (ADS)

    Johannes, Michelle; Bernstein, Noam

    Nanoscale coatings of alumina are used to stabilize surfaces for a variety of technologies. Diffusion of ions through these coatings is of primary importance: in some cases, diffusion is unwanted (e.g. corrosion) and in others (e.g. electrode materials), it is necessary. In this work DFT and AIMD calculations are used to investigate Li+ ion diffusion through a nano-layer of alumina, examining the phase (alpha, gamma, and amorphous), ion concentration, and electron count dependence. We look at the role of the surface itself in promoting diffusion. One of our main findings is that as the number of ions or charge increases, the diffusivity rises. We show how our data can explain electrochemical data from coated LiCoO2 cathodes and may point toward better and more efficient coatings for stabilizing electrodes.

  18. Fracture toughness and strength of 96% alumina

    SciTech Connect

    Price, D.B.; Chinn, R.E.; McNerney, K.R.; Brog, T.K.; Kim, C.Y.; Krutyholowa, M.W.; Chen, N.W.; Haun, M.J.

    1997-05-01

    There exists a need to understand the controlling factors that simultaneously impact strength and toughness in 96% alumina. The enhancement of both strength and toughness enables designers to extend the use limits and reliability for structural ceramics. This article presents mechanical property results from a group study examining the use of different alkaline-earth aluminosilicate intergranular compositions containing magnesium, calcium and strontium oxides (RO) in 96% alumina. Principal results address trends in indentation strength toughness and modulus of rupture. Trends in the data are presented relative to existing theories of thermal expansion mismatch toughening, grain-bridging crack-wake effect and crack deflection mechanisms. Strength is addressed in terms of strength after indentation, crack growth of indentation flaws and Weibull characterization for the strength distribution.

  19. Impact of AD995 alumina rods

    SciTech Connect

    Chhabildas, L.C.; Furnish, M.D.; Reinhart, W.D.; Grady, D.E.

    1997-10-01

    Gas guns and velocity interferometric techniques have been used to determine the loading behavior of an AD995 alumina rod 19 mm in diameter by 75 mm and 150 mm long, respectively. Graded-density materials were used to impact both bare and sleeved alumina rods while the velocity interferometer was used to monitor the axial-velocity of the free end of the rods. Results of these experiments demonstrate that (1) a time-dependent stress pulse generated during impact allows an efficient transition from the initial uniaxial strain loading to a uniaxial stress state as the stress pulse propagates through the rod, and (2) the intermediate loading rates obtained in this configuration lie between split Hopkinson bar and shock-loading techniques.

  20. Health Risk Assessments for Alumina Refineries

    PubMed Central

    Coffey, Patrick S.

    2014-01-01

    Objective: To describe contemporary air dispersion modeling and health risk assessment methodologies applied to alumina refineries and to summarize recent results. Methods: Air dispersion models using emission source and meteorological data have been used to assess ground-level concentrations (GLCs) of refinery emissions. Short-term (1-hour and 24-hour average) GLCs and annual average GLCs have been used to assess acute health, chronic health, and incremental carcinogenic risks. Results: The acute hazard index can exceed 1 close to refineries, but it is typically less than 1 at neighboring residential locations. The chronic hazard index is typically substantially less than 1. The incremental carcinogenic risk is typically less than 10−6. Conclusions: The risks of acute health effects are adequately controlled, and the risks of chronic health effects and incremental carcinogenic risks are negligible around referenced alumina refineries. PMID:24806721

  1. Activation of consolidation processes of alumina ceramics

    NASA Astrophysics Data System (ADS)

    Matrenin, S. V.; Zenin, B. S.; Tayukin, R. V.

    2016-02-01

    The methods for activating sintering ceramics based on Al2O3 by mechanical activation in the planetary mill, by adding in the mixture of nanopowders (NP) Al, Al2O3, and submicron powder TiO2, and by applying the technology of spark plasma sintering (SPS) are developed. It has been shown that adding the nanopowder up to 20 wt. % Al2O3 in a coarse powder α-Al2O3 activates the sintering process resulting in increased density and hardness of the sintered alumina ceramics. Substantial effect of increasing density of alumina ceramics due to adding the submicron powder TiO2 in the compound of initial powder mixtures has been established.

  2. Association between patients’ beliefs and oral antidiabetic medication adherence in a Chinese type 2 diabetic population

    PubMed Central

    Wu, Ping; Liu, Naifeng

    2016-01-01

    Purpose The objective of this study was to identify, using the theory of planned behavior (TPB), patients’ beliefs about taking oral antidiabetic drugs (OADs) as prescribed, and to measure the correlations between beliefs and medication adherence. Patients and methods We performed a cross-sectional study of type 2 diabetic patients using structured questionnaires in a Chinese tertiary hospital. A total of 130 patients were enrolled to be interviewed about TPB variables (behavioral, normative, and control beliefs) relevant to medication adherence. Medication adherence was assessed using the eight-item Morisky Medication Adherence Scale (MMAS-8). Spearman’s rank correlation was used to assess the association between TPB and MMAS-8. Logistic regression analysis was performed to examine the relationship between different variables and MMAS-8, with statistical significance determined at P<0.05. Results From 130 eligible Chinese patients with an average age of 60.6 years and a male proportion of 50.8%, a nonsignificant relationship between behavioral, normative, and the most facilitating control beliefs and OAD adherence was found in our study. Having the OADs on hand (P=0.037) was the only facilitating control belief associated with adherence behavior. Being away from home or eating out (P=0.000), not accepting the disease (P=0.000), ignorance of life-long drug adherence (P=0.038), being busy (P=0.001), or poor memory (P=0.008) were control belief barriers found to be correlated with poor adherence. TPB is the only important determinant influencing OAD adherence among all the factors (P=0.011). Conclusion The results indicate that the TPB model could be used to examine adherence to OADs. One facilitating control belief, and most of the barrier control beliefs of TPB were related to medication adherence among Chinese type 2 diabetes inpatients. It will be helpful to understand patients’ self-medication and provide methods to develop instruments for identifying

  3. Fast Glazing of Alumina/Silica Tiles

    NASA Technical Reports Server (NTRS)

    Creedon, J. F.; Gzowski, E. R.; Wheeler, W. H.

    1986-01-01

    Technique for applying ceramic coating to fibrous silica/alumina insulation tiles prevents cracks and substantially reduces firing time. To reduce thermal stresses in tile being coated, high-temperature, shorttime firing schedule implemented. Such schedule allows coating to mature while substrate remains at relatively low temperature, reducing stress differential between coating and substrate. Technique used to repair tiles with damaged coatings and possibly used in heat-treating objects made of materials having different thermal-expansion coefficients.

  4. High contrast laser marking of alumina

    NASA Astrophysics Data System (ADS)

    Penide, J.; Quintero, F.; Riveiro, A.; Fernández, A.; del Val, J.; Comesaña, R.; Lusquiños, F.; Pou, J.

    2015-05-01

    Alumina serves as raw material for a broad range of advanced ceramic products. These elements should usually be identified by some characters or symbols printed directly on them. In this sense, laser marking is an efficient, reliable and widely implemented process in industry. However, laser marking of alumina still leads to poor results since the process is not able to produce a dark mark, yielding bad contrast. In this paper, we present an experimental study on the process of marking alumina by three different lasers working in two wavelengths: 1064 nm (Near-infrared) and 532 nm (visible, green radiation). A colorimetric analysis has been carried out in order to compare the resulting marks and its contrast. The most suitable laser operating conditions were also defined and are reported here. Moreover, the physical process of marking by NIR lasers is discussed in detail. Field Emission Scanning Electron Microscopy, High Resolution Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy were also employed to analyze the results. Finally, we propose an explanation for the differences of the coloration induced under different atmospheres and laser parameters. We concluded that the atmosphere is the key parameter, being the inert one the best choice to produce the darkest marks.

  5. Compression Testing of Alumina Fiber Insulation

    NASA Technical Reports Server (NTRS)

    Vaughn, Wallace L.

    2006-01-01

    A series of tests were conducted to measure the response of alumina fiber insulation to compression loading. The alumina fiber insulation is a candidate gasket material for the Space Shuttle Government Furnished Equipment (GFE) Tile Overlay Repair. Tests were conducted at room temperature and 2300 F. The alumina fiber insulation is a fibrous insulation blanket which was supplied to Langley in two forms, a nominal 3 lb/ft3 version and a nominal 9 lb/ft3 version. The 3 lb/ft3 material was tested as sheets 0.15 and 0.25 inches thick and the 9 lb/ft3 material in sheets 1 inch thick. The material showed very non-linear compression behavior with the compressive resistance of the material increasing as the material was compressed. The 3 lb/ft3 0.15-inch thick material required 4.1 psi to reach the nominal installation thickness of 0.045 inches and retain a load of 2.1 lbs during unloading. Testing at 2300 F resulted in a stiffer more board-like material. The 3 lb/ft3 0.15-inch thick material retained 1 psi of compressive resistance after a 10 minute hold at 2300 F and 0.045 inches thickness.

  6. [Long term adherence to HAART in Senegal].

    PubMed

    Bastard, M; Fall, M Basty Koita

    2014-10-01

    Adherence is one of the main predictors of antiretroviral treatment success. A governmental initiative was launched in 1998 for HIV-infected patients in Senegal to provide access to highly active antiretroviral therapy (HAART). Adherence measurements, defined as pills taken/pills prescribed, were assessed between November 1999 and June 2010 using a pill count along with a questionnaire for 330 patients. Predictors of adherence and identification of adherence trajectories were explored through latent class mixed model. We also performed a survival analysis using Cox proportional hazard model. Three adherence behaviours were revealed as well as a better adherence for women. A third of patients had a high adherence trajectory over time and a third had an intermediate one. Male gender and low adherence behaviour over time were independently associated with a higher mortality rate. This study shows that an overall good adherence can be obtained in the long term in Senegal, suggests a better adherence for women and points out a large subsample of patients with intermediate level of adherence behaviour who are at risk for developing resistance to antiretroviral drugs. PMID:24615434

  7. Bisphosphonates adherence for treatment of osteoporosis

    PubMed Central

    2013-01-01

    Background Osteoporosis is a disease of bone metabolism in which bisphosphonates (BPS) are the most common medications used in its treatment, whose main objective is to reduce the risk of fractures. The aim of this study was to conduct a systematic review on BPs adherence for treatment of osteoporosis. Methods Systematic review of articles on BPs adherence for treatment of osteoporosis, indexed on MEDLINE (via PubMed) databases, from inception of databases until January 2013. Search terms were “Adherence, Medication” (MeSH term), “Bisphosphonates” (MeSH term), and “Osteoporosis” (MeSH term). Results Of the 78 identified studies, 27 met the eligibility criteria. Identified studies covered a wide range of aspects regarding adherence and associated factors, adherence and fracture, adherence and BPs dosage. The studies are mostly observational, conducted with women over 45 years old, showing low rates of adherence to treatment. Several factors may influence adherence: socio-economic and cultural, participation of physicians when guidance is given to the patient, the use of bone turnover markers, and use of generic drugs. The monthly dosage is associated with greater adherence compared to weekly dosage. Conclusions Considering the methodological differences between the studies, the results converge to show that adherence to treatment of osteoporosis with BPs is still inadequate. Further experimental studies are needed to evaluate the adherence and suggest new treatment options. PMID:23705998

  8. Synthesis and properties of high-purity alumina

    SciTech Connect

    Martin, E.S.; Weaver, M.L. . Chemical Systems Div.)

    1993-07-01

    High-purity alumina is intended primarily for the high-pressure sodium-vapor lamp envelope market and other specialty alumina applications such as abrasives, catalysts, and structural ceramics. High-purity alumina must calcine to Al[sub 2]O[sub 3] with minimal metal impurities ([>=]99.99% Al[sub 2]O[sub 3]). Sulfate and chloride impurities are also undesirable. High-purity alumina should have less than 20ppm alkali and alkaline-earth metals, and less than 10 ppm each in transition-metal impurities. A process for synthesizing alumina by converting pure aluminum metal to aluminum hydroxide and the resultant alumina properties are described.

  9. A simple procedure to prepare spherical {alpha}-alumina powders

    SciTech Connect

    Liu Hongyu; Ning Guiling Gan Zhihong; Lin Yuan

    2009-04-02

    Spherical {alpha}-alumina powders were prepared by the controlled hydrolysis of aluminum isopropoxide in a hydrolysis system consisting of octanol and acetonitrile. Diverse solvents to dissolve reactant formed diverse hydrolysis systems and affected particle shape of {alpha}-alumina powders. The precursors crystallized to {gamma}-alumina at 1000 deg. C and converted to {alpha}-alumina at 1150 deg. C without intermediate phases. The particle morphology of precursor was retained after it crystallized to {alpha}-alumina. The heating rate influenced the particle shape and the state of agglomeration during calcination process. The thermal properties of the precursors were characterized by thermal gravimetric and differential thermal analysis. X-ray diffraction technique was used to confirm the conversion of crystalline phase of alumina powders from amorphous to {alpha}-phase. Transmission electron microscopy was used to investigate the morphologies and size of the precursors and products.

  10. New experience with alumina-on-alumina ceramic bearings for total hip arthroplasty.

    PubMed

    D'Antonio, James; Capello, William; Manley, Michael; Bierbaum, Benjamin

    2002-06-01

    A major challenge for total hip arthroplasty is to minimize wear and osteolysis in young, active patients. Alumina ceramic bearings have shown superior wear resistance and lubrication and do not carry the risk of ion release. In a prospective randomized study, 514 hips were implanted. All patients (average age, 53 years) received the same press-fit hydroxyapatite coated femoral stem; two thirds (345 hips) received alumina ceramic bearings, and one third (169 hips) received a cobalt-chrome-on-polyethylene bearing. At a mean follow-up of 35.2 months (range, 24-48 months), there was no significant difference in clinical performance between the patient cohorts. No ceramic fracture or alumina ceramic bearing failure occurred. This new experience involves the use of improved ceramic materials and new design considerations that eliminate the risks and complications of past experiences with ceramic implants and provides a safe bearing option for young patients. PMID:12066265

  11. Free-standing alumina nanobottles and nanotubes pre-integrated into nanoporous alumina membranes

    NASA Astrophysics Data System (ADS)

    Fang, Jinghua; Levchenko, Igor; (Ken Ostrikov, Kostya

    2014-08-01

    A novel interfacial structure consisting of long (up to 5 μm), thin (about 300 nm), highly-ordered, free-standing, highly-reproducible aluminum oxide nanobottles and long tubular nanocapsules attached to a rigid, thin (less than 1 μm) nanoporous anodic alumina membrane is fabricated by simple, fast, catalyst-free, environmentally friendly voltage-pulse anodization. A growth mechanism is proposed based on the formation of straight channels in alumina membrane by anodization, followed by neck formation due to a sophisticated voltage control during the process. This process can be used for the fabrication of alumina nanocontainers with highly controllable geometrical size and volume, vitally important for various applications such as material and energy storage, targeted drug and diagnostic agent delivery, controlled drug and active agent release, gene and biomolecule reservoirs, micro-biologically protected platforms, nano-bioreactors, tissue engineering and hydrogen storage.

  12. Adherence to Methotrexate therapy in Rheumatoid Arthritis

    PubMed Central

    Arshad, Nasim; Ahmad, Nighat Mir; Saeed, Muhammad Ahmed; Khan, Saira; Batool, Shabnam; Farman, Sumaira

    2016-01-01

    Objective: To determine adherence to methotrexate (MTX) therapy in patients with Rheumatoid Arthritis (RA) and to identify factors that promote either adherence or non adherence. Methods: One hundred Rheumatoid Arthritis patients on MTX for at least two months were enrolled. Questionnaire was completed by direct interview. Details recorded were, demographics (age, sex, education, monthly income), disease duration, duration on MTX and current dose. Disease Activity Score on 28 joint counts (DAS 28) at the current visit, concomitant drugs taken and number of doses of MTX missed in the previous 8 weeks were noted. Non adherence was defined as omission of any three or more prescribed doses of MTX in previous 8 week. Patients were asked for the factors that motivated their adherence to MTX as well as factors for non adherence. Presence of side effects due to MTX was also recorded. Result: Non adherence was found among 23% of cases. Patients of low socioeconomic group (p <0.0001) and on MTX for longer duration (p <0.001) had higher non adherence. Non adherent patients had significantly higher disease activity as measured by DAS 28 (p<0.001). Good counseling and education by the doctor was a strong predictor of adherence (p <0.001). Lack of affordability (p <0.001); lack of availability at local pharmacy (p <0.001); lack of family support (p <0.001) and lack of awareness regarding need and importance of MTX (p < 0.001were found as significant factors for non adherence. Conclusion: MTX non adherence in RA is noted in about one fourth of study group. Various economical and social issues lead to non adherence but good patient education and counseling by doctor could promote adherence in this study group. PMID:27182251

  13. Adherence to cardiovascular medications in the South Asian population: A systematic review of current evidence and future directions

    PubMed Central

    Akeroyd, Julia M; Chan, Winston J; Kamal, Ayeesha K; Palaniappan, Latha; Virani, Salim S

    2015-01-01

    AIM: To review methods of assessing adherence and strategies to improve adherence to cardiovascular disease (CVD) medications, among South Asian CVD patients. METHODS: We conducted a systematic review of English language studies that examined CVD medication adherence in South Asian populations from 1966 to April 1, 2015 in SCOPUS and PubMed. Working in duplicate, we identified 61 studies. After exclusions, 26 studies were selected for full text review. Of these, 17 studies were included in the final review. We abstracted data on several factors including study design, study population, method of assessing adherence and adherence rate. RESULTS: These studies were conducted in India (n = 11), Pakistan (n = 3), Bangladesh (n = 1), Nepal (n = 1) and Sri Lanka (n = 1). Adherence rates ranged from 32%-95% across studies. Of the 17 total publications included, 10 focused on assessing adherence to CVD medications and 7 focused on assessing the impact of interventions on medication adherence. The validated Morisky Medication Adherence Scale (MMAS) was used as the primary method of assessing adherence in five studies. Three studies used validated questionnaires similar to the MMAS, and one study utilized Medication Event Monitoring System caps, with the remainder of the studies utilizing pill count and self-report measures. As expected, studies using non-validated self-report measures described higher rates of adherence than studies using validated scale measurements and pill count. The included intervention studies examined the use of polypill therapy, provider education and patient counseling to improve medication adherence. CONCLUSION: The overall medication adherence rates were low in the region, which suggest a growing need for future interventions to improve adherence. PMID:26730300

  14. Alumina Solubility and Diffusion Coefficient of the Dissolved Alumina Species in Low-Temperature Fluoride Electrolytes

    NASA Astrophysics Data System (ADS)

    Frazer, E. J.; Thonstad, J.

    2010-06-01

    The solubility of alumina was measured by rotating an alumina cylinder (~500 rpm) in a high-purity melt for ~3 to 6 hours, crushing and sampling the frozen melt, and determining the oxygen content in a Leco analyzer. The alumina solubilities determined were as follows: (1) 3.2 ± 0.3 wt pct in NaF-AlF3 eutectic at 1023 K (750 °C); (2) 3.0 ± 0.3 wt pct in NaF-AlF3-CaF2 (5 wt pct) at 1023 K (750 °C); and (3) 5.2 ± 0.5 wt pct in a KF-AlF3 eutectic at 1003 K (730 °C). The alumina solubility in the KF-AlF3 eutectic was 2 wt pct more than in the sodium analogue, offering the possibility of operating a low-temperature aluminum smelting cell without the need for an alumina slurry. The diffusion coefficient of the dissolved alumina species was determined in the NaF-AlF3 eutectic at 1023 K (750 °C) using the rotating disc method and applying the Levich equation. Through a limited range of rotation rates, the system seemed to be mass-transfer controlled, and the diffusion coefficient was estimated to be in the range 1.8 to 2.2 × 10-6 cm2 s-1. This value is about five times lower than the values encountered at traditional aluminum smelting temperatures (~1233 K (960 °C)) and would result in relatively low mass transfer coefficients.

  15. Method for preparing Pb-.beta."-alumina ceramic

    DOEpatents

    Hellstrom, Eric E.

    1986-01-01

    A process is disclosed for preparing impermeable, polycrystalline samples of Pb-.beta."-alumina ceramic from Na-.beta."-alumina ceramic by ion exchange. The process comprises two steps. The first step is a high-temperature vapor phase exchange of Na by K, followed by substitution of Pb for K by immersing the sample in a molten Pb salt bath. The result is a polycrystalline Pb-.beta."-alumina ceramic that is substantially crack-free.

  16. Sintering of beta-type alumina bodies using alpha-alumina encapsulation

    DOEpatents

    McEntire, Bryan J.; Virkar, Anil V.

    1981-01-01

    A method of sintering a shaped green, beta-type alumina body comprising: (A) inserting said body into an open chamber prepared by exposing the interior surface of a container consisting essentially of at least about 50 weight percent of alpha-alumina and a remainder of other refractory material to a sodium oxide or sodium oxide producing environment; (B) sealing the chamber; and heating the chamber with the shaped body encapsulated therein to a temperature and for a time necessary to sinter said body to the desired density. The encapsulation chamber prepared as described above is also claimed.

  17. Porous Alumina Prepared from Diethylaluminum Amide, Acetone, and Water

    SciTech Connect

    Wilcox, Lize; Burnside, Gaylen G.; Kiranga, Beatrice; Shekhawat, Ritu; Mazumder, Malay K.; Hawk, Roger M.; Lindquist, David A.; Burton, Sarah D.)

    2003-01-14

    Mesoporous aluminas are valued catalysts because they exhibit a combination of properties that allow both long life and activity. The surface area, acidity, stability, and pore size of the alumina directly influence lifetime and activity. Increased surface area and acidity, along with decreased pore size, lead to increased activity. However, these same characteristics also decrease lifetime. The properties of alumina are mutually dependent, and can be mutually opposed. Aluminas with better activity and longer life will result from a better understanding of these trends given the preparative method and thermal history.

  18. Modelling the initial stage of porous alumina growth during anodization

    NASA Astrophysics Data System (ADS)

    Aryslanova, E. M.; Alfimov, A. V.; Chivilikhin, S. A.

    2013-05-01

    Artificially on the surface of aluminum there may be build a thick layer of Al2O3, which has a porous structure. In this paper we present a model of growth of porous alumina in the initial stage of anodizing, identifying dependencies anodizing parameters on the rate of growth of the film and the distance between the pores and as a result of the created model equations were found for changes in the disturbance of alumina for the initial stage of anodizing aluminum oxide porous border aluminum-alumina and alumina-electrolyte, with the influence of surface diffusion of aluminum oxide.

  19. Patterns and obstacles to oral antidiabetic medications adherence among type 2 diabetics in Ismailia, Egypt: a cross section study

    PubMed Central

    Heissam, Khaled; Abuamer, Zeinab; El-Dahshan, Nahed

    2015-01-01

    Introduction Diabetes is a costly and increasingly common chronic disease. Effective management of diabetes to achieve glycemic control improves patient quality of life. Adherence rates to drug regimens in patients with type 2 diabetes are relatively low and vary widely between populations. There are many factors that could affect patient adherence to drug therapy. The aim of the present study was assessing patterns and obstacles to adherence of type 2 diabetic patients to their oral hypoglycemic drugs. Methods The present work is a descriptive cross section study, carried on type 2 diabetic patients who were on oral hypoglycemic drugs. Data concerning adherence to drugs was assessed using measure treatment adherence scale (MTA). Results A total of 372 (55.59% males and 44.41% females) patients with type-2 diabetes fulfilled the inclusion criteria and included in the study. Among the participants, 26.1% were found to have good adherence, 47.9% had a fair adherence, and 26% had poor adherence. Conclusion The overall rate of medication adherence among the diabetic patients population was suboptimal and non-acceptable. Evaluation of adherence is vital for patients with diabetes in order to determine factors and barriers affecting the adherence and to manage them. PMID:26113919

  20. Medication Adherence in People With Parkinson Disease.

    PubMed

    Shin, Ju Young; Habermann, Barbara

    2016-01-01

    Parkinson disease (PD) is the second most common neurodegenerative disorder in the United States. Because there is no cure for PD currently, pharmacological therapy is the mainstay of PD symptom management. Despite the importance of medication adherence in PD, several studies have reported medication nonadherence and/or suboptimal adherence. This literature review provides an overview of medication adherence issues in people with PD. Articles were identified for this study using computerized database searches and journal hand searches. Of the 72 medication adherence articles reviewed, the following articles were eligible for this review: (a) 10 articles measuring medication adherence in people with PD, (b) four medication adherence intervention articles, and (c) six studies of medication adherence in hospitalized settings. The importance of adherence assessment and strategies in improving medication adherence are discussed with the goal of improving symptom management and clinical outcomes in people with PD. Because medication taking is a complex and multifaceted phenomena, patient-centered, theory-driven interventions are needed to improve medication adherence and quality of care and life in people with PD. PMID:27224682

  1. Scale

    ERIC Educational Resources Information Center

    Schaffhauser, Dian

    2009-01-01

    The common approach to scaling, according to Christopher Dede, a professor of learning technologies at the Harvard Graduate School of Education, is to jump in and say, "Let's go out and find more money, recruit more participants, hire more people. Let's just keep doing the same thing, bigger and bigger." That, he observes, "tends to fail, and fail…

  2. Damping Behavior of Alumina Epoxy Nano-Composites

    NASA Astrophysics Data System (ADS)

    Katiyar, Priyanka; Kumar, Anand

    2016-05-01

    Polymer nano composites, consisting of a polymer matrix with nanoparticle filler, have been predicted to be one of the most beneficial applications of nanotechnology. Addition of nano particulates to a polymer matrix enhances its performance by capitalizing on the nature and properties of the nano-scale fillers. The damping behavior of composites with nano structured phases is significantly different from that of micro structured materials. Viscoelastic homopolymer exhibit a high material damping response over a relatively narrow range of temperature and frequencies. In many practical situations, a polymeric structure is required to possess better strength and stiffness properties together with a reasonable damping behavior. Viscoelastic polymers show higher loss factor beyond the glassy region which comes with a significant drop in the specific modulus. Addition of nano alumina particles to epoxy leads to improved strength and stiffness properties with an increase in glass transition temperature while retaining its damping capability. Experimental investigations are carried out on composite beam specimen fabricated with different compositions of alumina nano particles in epoxy to evaluate loss factor, tan δ. Impact damping method is used for time response analysis. A single point Laser is used to record the transverse displacement of a point on the composite beam specimen. The experimental results are compared with theoretical estimation of loss factor using Voigt estimation. The effect of inter phase is included in theoretical estimation of loss factor. The result reveals that the study of interface properties is very important in deriving the overall loss factor of the composite since interface occupies a significant volume fraction in the composite.

  3. Predictors of decline in medication adherence: Results from CoSMO

    PubMed Central

    Krousel-Wood, Marie; Joyce, Cara; Holt, Elizabeth; Muntner, Paul; Webber, Larry S; Morisky, Donald E; Frohlich, Edward D; Re, Richard N

    2011-01-01

    Few data are available on the predictors of decline in antihypertensive medication adherence and the association of decline in adherence with subsequent blood pressure (BP) control. The current analysis included 1,965 adults from the Cohort Study of Medication Adherence among Older Adults (CoSMO) recruited between August 2006 and September 2007. Decline in antihypertensive medication adherence was defined as a ≥ 2 point decrease on the 8-item Morisky Medication Adherence Scale assessed during telephone surveys 1 and 2 years following baseline. Risk factors for decline in adherence were collected using telephone surveys and administrative databases. BP was abstracted from outpatient records. The annual rate for a decline in adherence was 4.3% (159 participants experienced a decline). After multivariable adjustment, a decline in adherence was associated with an odds ratio (OR) for uncontrolled BP (≥140/90 mm Hg) at follow up of 1.68 (95% CI: 1.01, 2.80). Depressive symptoms (OR 1.84, 95%CI 1.20, 2.82) and a high stressful life events score (OR 1.68, 95% CI 1.19, 2.38) were associated with higher ORs for a decline in adherence. Female gender (OR 0.61, 95% CI 0.42, 0.88); being married (OR 0.68, 95% CI 0.47, 0.98); and calcium channel blocker use (OR 0.68, 95% CI 0.48, 0.97) were associated with lower ORs for decline. In summary, a decline in antihypertensive medication adherence was associated with uncontrolled BP. Modifiable factors associated with decline were identified. Further research is warranted to determine if interventions can prevent the decline in antihypertensive medication adherence and improve BP control. PMID:21968751

  4. Explaining Adherence Success in Sub-Saharan Africa: An Ethnographic Study

    PubMed Central

    Ware, Norma C; Idoko, John; Kaaya, Sylvia; Biraro, Irene Andia; Wyatt, Monique A; Agbaji, Oche; Chalamilla, Guerino; Bangsberg, David R

    2009-01-01

    Background Individuals living with HIV/AIDS in sub-Saharan Africa generally take more than 90% of prescribed doses of antiretroviral therapy (ART). This number exceeds the levels of adherence observed in North America and dispels early scale-up concerns that adherence would be inadequate in settings of extreme poverty. This paper offers an explanation and theoretical model of ART adherence success based on the results of an ethnographic study in three sub-Saharan African countries. Methods and Findings Determinants of ART adherence for HIV-infected persons in sub-Saharan Africa were examined with ethnographic research methods. 414 in-person interviews were carried out with 252 persons taking ART, their treatment partners, and health care professionals at HIV treatment sites in Jos, Nigeria; Dar es Salaam, Tanzania; and Mbarara, Uganda. 136 field observations of clinic activities were also conducted. Data were examined using category construction and interpretive approaches to analysis. Findings indicate that individuals taking ART routinely overcome economic obstacles to ART adherence through a number of deliberate strategies aimed at prioritizing adherence: borrowing and “begging” transport funds, making “impossible choices” to allocate resources in favor of treatment, and “doing without.” Prioritization of adherence is accomplished through resources and help made available by treatment partners, other family members and friends, and health care providers. Helpers expect adherence and make their expectations known, creating a responsibility on the part of patients to adhere. Patients adhere to promote good will on the part of helpers, thereby ensuring help will be available when future needs arise. Conclusion Adherence success in sub-Saharan Africa can be explained as a means of fulfilling social responsibilities and thus preserving social capital in essential relationships. PMID:19175285

  5. Improving Post-Discharge Medication Adherence in Patients with CVD: A Pilot Randomized Trial

    PubMed Central

    Oliveira-Filho, Alfredo D.; Morisky, Donald E.; Costa, Francisco A.; Pacheco, Sara T.; Neves, Sabrina F.; Lyra-Jr, Divaldo P.

    2014-01-01

    Background Effective interventions to improve medication adherence are usually complex and expensive. Objective To assess the impact of a low-cost intervention designed to improve medication adherence and clinical outcomes in post-discharge patients with CVD. Method A pilot RCT was conducted at a teaching hospital. Intervention was based on the four-item Morisky Medication Adherence Scale (MMAS-4). The primary outcome measure was medication adherence assessed using the eight-item MMAS at baseline, at 1 month post hospital discharge and re-assessed 1 year after hospital discharge. Other outcomes included readmission and mortality rates. Results 61 patients were randomized to intervention (n = 30) and control (n = 31) groups. The mean age of the patients was 61 years (SD 12.73), 52.5% were males, and 57.4% were married or living with a partner. Mean number of prescribed medications per patient was 4.5 (SD 3.3). Medication adherence was correlated to intervention (p = 0.04) and after 1 month, 48.4% of patients in the control group and 83.3% in the intervention group were considered adherent. However, this difference decreased after 1 year, when adherence was 34.8% and 60.9%, respectively. Readmission and mortality rates were related to low adherence in both groups. Conclusion The intervention based on a validated patient self-report instrument for assessing adherence is a potentially effective method to improve adherent behavior and can be successfully used as a tool to guide adherence counseling in the clinical visit. However, a larger study is required to assess the real impact of intervention on these outcomes. PMID:25590930

  6. Patient Characteristics and Variability in Adherence and Competence in Cognitive-Behavioral Therapy for Panic Disorder

    PubMed Central

    Boswell, James F.; Gallagher, Matthew W.; Sauer-Zavala, Shannon E.; Bullis, Jacqueline; Gorman, Jack M.; Shear, M. Katherine; Woods, Scott; Barlow, David H.

    2013-01-01

    Although associations with outcome have been inconsistent, therapist adherence and competence continues to garner attention, particularly within the context of increasing interest in the dissemination, implementation, and sustainability of evidence-based treatments. To date, research on therapist adherence and competence has focused on average levels across therapists. With a few exceptions, research has failed to address multiple sources of variability in adherence and competence, identify important factors that might account for variability, or take these sources of variability into account when examining associations with symptom change. Objective (a) statistically demonstrate between- and within-therapist variability in adherence and competence ratings and examine patient characteristics as predictors of this variability and (b) examine the relationship between adherence/competence and symptom change. Method Randomly selected audiotaped sessions from a randomized controlled trial of cognitive-behavioral therapy for panic disorder were rated for therapist adherence and competence. Patients completed a self-report measure of panic symptom severity prior to each session and the Inventory of Interpersonal Problems-Personality Disorder Scale prior to the start of treatment. Results Significant between- and within-therapist variability in adherence and competence were observed. Adherence and competence deteriorated significantly over the course of treatment. Higher patient interpersonal aggression was associated with decrements in both adherence and competence. Neither adherence nor competence predicted subsequent panic severity. Conclusions Variability and “drift” in adherence and competence can be observed in controlled trials. Training and implementation efforts should involve continued consultation over multiple cases in order to account for relevant patient factors and promote sustainability across sessions and patients. PMID:23339537

  7. Assessing the adherence behavior of glaucoma patients to topical eye drops

    PubMed Central

    Welge-Lussen, Ulrich; Weise, Stefanie; Yu, Alice L

    2015-01-01

    Purpose The goal of this study was to determine the adherence of glaucoma patients to their topical glaucoma medication. Furthermore, the relationships between the adherence behavior and the patients’ demographic data, clinical characteristics, and their knowledge about glaucoma were evaluated. Methods This was a prospective study of 123 patients with primary open-angle glaucoma who were given two standardized questionnaires. The first questionnaire at time point T1 comprised a knowledge assessment and the self-reported adherence measures Adherence to Refills and Medication Scale 2 (ARMS2), visual analogue scale for adherence (VAS-AD), and missed doses in the past 14 days. Two months later at time point T2, a second questionnaire reevaluated the adherence measures ARMS2, VAS-AD, and missed doses in the past 14 days. Results There was a good correlation among all the three adherence measures at T1 and T2. The mean values of ARMS2 were in the lower range, with 3.38 at T1 and 2.8 at T2. The VAS-AD detected that 18.5% of patients always took their eye drops correctly, and 77.9% of patients reported not to have missed a single dose in the past 14 days. There was no significant correlation between the patients’ demographic data or knowledge about glaucoma and the adherence measures ARMS2 or VAS-AD. Among the clinical characteristics, only single-eye blindness showed a significant correlation with VAS-AD. Conclusion In this study, no general relationships were found between medication adherence and the patients’ demographic data, clinical characteristics, or knowledge about glaucoma. It may be assumed that more individualized strategies are required to optimize adherence behavior. PMID:25565780

  8. Segregation phenomena at growing alumina/alloy interfaces

    SciTech Connect

    Hou, Peggy Y.

    2005-03-30

    The chemistry and structure at the scale/alloy interface are important factors governing scale adhesion. The chemical changes can occur from segregation of impurities in the alloy, such as sulphur and carbon, or alloying elements such as chromium, aluminium and reactive elements. This paper reviews studies of the changes of interfacial composition with oxidation time for Al{sub 2}O{sub 3} formed on several model alumina-forming alloys, and tries to relate that to the interfacial strength. Results show that sulphur segregation to oxide/metal interfaces can indeed occur, but the type and amount of segregants at the interface depend on the alloy composition and the interface structure. Co-segregation of impurities with alloying elements can also occur, resulting in multi-layer segregants at the interface. Sulphur-containing interfaces are indeed weaker, but the major role of sulphur is to enhance interfacial void formation. Reactive elements in the alloy not only gather sulfur but also exert an additional positive effect on scale adhesion.

  9. Soil adherence to human skin

    SciTech Connect

    Driver, J.H.; Konz, J.J.; Whitmyre, G.K. )

    1989-12-01

    Dermal exposure to soils contaminated with toxic chemicals represents a potential public health hazard. These soils, contaminated with chemicals such as PCBs and dioxins, may be found at various locations throughout the US. Furthermore, dermal contact with pesticide-containing particles and contaminated soil particles is of importance for exposures to agricultural workers who reenter fields after pesticide application. With respect to dermal exposure to pesticide-contaminated particulate matter, several occurrences of human toxicity to ethyl parathion in citrus groves have been reported. These exposures resulted from dermal contact with high concentrations of the toxic transformation product paraoxon in soil dust contaminated as a result of application of pesticide to the overhead foliage of trees. To assess dermal exposure to chemically-contaminated soil at sites of concern, dermal adherence of soil must be determined prior to the assessment of dermal absorption. The purpose of the experiment reported herein was to determine the amount of soil (mg/cm{sup 2}) that adheres to adult hands under various soil conditions. These conditions include the type of soil, the organic content of the soil, and the particle size of the soil.

  10. Geriatric syndromes are potential determinants of the medication adherence status in prevalent dialysis patients

    PubMed Central

    Chao, Chia-Ter

    2016-01-01

    Background. Geriatric syndromes (GS) exhibit high prevalence in patients with end-stage renal disease (ESRD) under chronic dialysis irrespective of age. We sought to determine whether GS influences medication adherence in ESRD patients. Methods. A prospective cohort of chronic dialysis patients was assembled. The presence of GS components, including frailty/prefrailty, polypharmacy, and malnutrition, were ascertained through a validated questionnaire, electronic records and chart abstraction, and laboratory tests. The severity of medication non-adherence was defined using the eight-item Morisky Medication Adherence Scale (MMAS). Multiple logistic regression analysis was performed targeting MMAS results and incorporating relevant clinical features and GS. Results. The prevalence of frailty/pre-frailty, polypharmacy, and hypoalbuminemia/ malnutrition among the enrolled participants was 66.7%, 94%, and 14%, respectively. The average MMAS scores in these dialysis patients were 2 ± 1.7 (range, 0–6), with only 15.7% exhibiting high medication adherence. Multiple regression analyses showed that the absence of frailty/pre-frailty (P = 0.01) were significantly associated with poorer medication adherence, while the presence of polypharmacy (P = 0.02) and lower serum albumin, a potential sign of malnutrition (P = 0.03), were associated with poor adherence in another model. Conclusion. This study is among the very few reports addressing GS and medication adherence, especially in ESRD patients. Interventions targeting frailty, polypharmacy, and malnutrition might potentially improve the medication non-adherence and symptom control in these pill-burdened patients. PMID:27326380

  11. Improving hand hygiene adherence among nursing staff.

    PubMed

    Harne-Britner, Sarah; Allen, Marianne; Fowler, Kimberly A

    2011-01-01

    This quasi-experimental study explored initial and sustained effects of educational and behavioral interventions on hand hygiene adherence and the relationships between hand hygiene adherence and health care-associated infections. Education paired with positive reinforcement behavioral interventions significantly improved hand hygiene adherence after the first month (χ² = 4.27; P = .039); however, the improvement was not sustained over 6 months. There were no significant differences in infection rates between the treatment and control groups. PMID:20407392

  12. Patient Characteristics Associated with Medication Adherence

    PubMed Central

    Rolnick, Sharon J; Pawloski, Pamala A.; Hedblom, Brita D.; Asche, Stephen E.; Bruzek, Richard J.

    2013-01-01

    Objective Despite evidence indicating therapeutic benefit for adhering to a prescribed regimen, many patients do not take their medications as prescribed. Non-adherence often leads to morbidity and to higher health care costs. The objective of the study was to assess patient characteristics associated with medication adherence across eight diseases. Design Retrospective data from a repository within an integrated health system was used to identify patients ≥18 years of age with ICD-9-CM codes for primary or secondary diagnoses for any of eight conditions (depression, hypertension, hyperlipidemia, diabetes, asthma or chronic obstructive pulmonary disease, multiple sclerosis, cancer, or osteoporosis). Electronic pharmacy data was then obtained for 128 medications used for treatment. Methods Medication possession ratios (MPR) were calculated for those with one condition and one drug (n=15,334) and then for the total population having any of the eight diseases (n=31,636). The proportion of patients adherent (MPR ≥80%) was summarized by patient and living-area (census) characteristics. Bivariate associations between drug adherence and patient characteristics (age, sex, race, education, and comorbidity) were tested using contingency tables and chi-square tests. Logistic regression analysis examined predictors of adherence from patient and living area characteristics. Results Medication adherence for those with one condition was higher in males, Caucasians, older patients, and those living in areas with higher education rates and higher income. In the total population, adherence increased with lower comorbidity and increased number of medications. Substantial variation in adherence was found by condition with the lowest adherence for diabetes (51%) and asthma (33%). Conclusions The expectation of high adherence due to a covered pharmacy benefit, and to enhanced medication access did not hold. Differences in medication adherence were found across condition and by

  13. Anisotropic shrinkage characteristics of tape cast alumina

    NASA Astrophysics Data System (ADS)

    Patwardhan, Jaideep Suresh

    Dimensional control during sintering is a major issue in ceramics processing to avoid high post-sintering costs associated with machining of the fired ceramic part to desired tolerances and dimensions. Ceramic forming processes such as tape casting, injection molding, and extrusion involve shear of anisotropic particles resulting in preferential alignment of the particles in the green body. This preferential alignment causes directionality in mechanical, electrical, optical, and magnetic properties and most importantly warpage or distortion during sintering. A large effort has been devoted to synthesizing ceramic green bodies with minimal density gradients and uniform packing and modeling the sintering behavior evolution but little effort has been devoted to characterizing orientation of particles and the effect of preferential alignment on sintering shrinkage anisotropy. A systematic study was initiated to study the effect of processing variables such as shear rate, solids loading, temperature, and binder content on aqueous tape cast alumina. Three different alumina systems: A16-SG, Baikowski RC-UFX DBM and RC-LS DBM were investigated. Aqueous tapes of high solids loading alumina (56 vol. %) were tape cast at various speeds and thicknesses and assuming plane Couette flow a shear rate regime of 21--270 s-1 was investigated. Higher shear rates and high solids loading resulted in higher in-plane anisotropy whereas the anisotropy in the thickness direction was higher for low solids loading systems. The anisotropy was found to be fairly constant above a certain critical shear rate (˜100 s-1) irrespective of the temperature and the solids loading and this correlated with the viscosity-shear rate relationship of the cast slips. The higher shrinkage anisotropy in the thickness direction for the low solids loading systems (35 and 45 vol. %) was attributed to the higher amount of organics in the slip required to sustain the suitable viscosity for tape casting and

  14. Intercalation of water into lithium. beta. -alumina

    SciTech Connect

    Dudney, N J; Bates, J B; Wang, J C; Brown, G M; Larson, B C; Engstrom, H

    1981-01-01

    Infrared absorption, neutron diffraction and weight loss techniques have been used to investigate the hydration of single crystals of Li ..beta..-alumina. The hydration is a reversible intercalation reaction. Up to approximately two water molecules per formula unit can penetrate the conduction plane. Other protonated species are formed from the dissociation of the molecular water. The rate of hydration is controlled by the diffusion of water in the conduction plane. A likely diffusion mechanism requires dissociation of the water and an interstitialcy motion of the oxygen.

  15. Porosity in plasma sprayed alumina coatings

    SciTech Connect

    Ilavsky, J.; Herman, H.; Berndt, C.C.; Goland, A.N.; Long, G.G.; Krueger, S.; Allen, A.J.

    1994-03-01

    Small-angle neutron scattering (SANS) was used to study the porosity of plasma sprayed deposits of alumina in as-sprayed and heat-treated conditions. SANS results were compared with mercury intrusion porosimetry (MIP) and water immersion techniques. Multiple small-angle neutron scattering yields a volume-weighted effective pore radius (R{sub eff}), for pores with sizes between 0.08 and 10{mu}m, the pore volume in this size region, and from the Porod region, the surface area of pores of all sizes.

  16. Crack growth resistance of textured alumina

    NASA Technical Reports Server (NTRS)

    Salem, Jonathan A.; Shannon, John L., Jr.; Bradt, Richard C.

    1989-01-01

    The crack growth resistance of a textured, extruded alumina body was compared with that of anisotropic, isopressed body of similar grain size, density, and chemistry. R-curve levels reflected the preferred orientation; however, R-curve slopes were the same in all instances, implying a similar crack growth-resistive mechanism. Three orthogonal orientations of crack growth in the two structures exhibited similar forms of K(IR) versus Delta-a curves, for which a schematic diagram for polycrystalline ceramics is proposed.

  17. Conduction mechanism of single-crystal alumina

    NASA Technical Reports Server (NTRS)

    Will, Fritz G.; Delorenzi, Horst G.; Janora, Kevin H.

    1992-01-01

    The fully guarded three-terminal technique was used to perform conductivity measurements on single-crystal alumina at temperatures of 400-1300 C. The conductivity was also determined as a function of time at various temperatures and applied fields. Further, the fractions of the current carried by Al and O ions (ionic transference numbers) were determined from long-term transference experiments in the temperature range 1100-1300 C. A mathematical model of the conduction mechanism is proposed, and model predictions are compared with experimental results.

  18. Improved Synthesis Of Potassium Beta' '-Alumina

    NASA Technical Reports Server (NTRS)

    Williams, Roger M.; Jeffries-Nakamura, Barbara; Ryan, Margaret A.; O'Connor, Dennis E.; Kisor, Adam; Underwood, Mark

    1996-01-01

    Improved formulations of precursor materials synthesize nearly-phase-pure potassium beta' '-alumina solid electrolyte (K-BASE) powder. Materials are microhomogeneous powders (or, alternatively, gels) containing K(+,) Mg(2+), and Al(3+). K-BASE powder produced used in potassium-working-fluid alkali-metal thermal-to-electric conversion (K-AMTEC), in which heat-input and heat-rejection temperatures lower than sodium-working-fluid AMTEC (Na-AMTEC). Additional potential use lies in purification of pottassium by removal of sodium and calcium.

  19. Medication Adherence: A Call for Action

    PubMed Central

    Bosworth, Hayden B.; Granger, Bradi B.; Mendys, Phil; Brindis, Ralph; Burkholder, Rebecca; Czajkowski, Susan M.; Daniel, Jodi G.; Ekman, Inger; Ho, Michael; Johnson, Mimi; Kimmel, Stephen E.; Liu, Larry Z; Musaus, John; Shrank, William H.; Buono, Elizabeth Whalley; Weiss, Karen; Granger, Christopher B.

    2013-01-01

    Poor adherence to efficacious cardiovascular related medications has led to considerable morbidity, mortality, and avoidable health care costs. This paper provides results of a recent think tank meeting in which various stakeholder groups representing key experts from consumers, community health providers, the academic community, decision-making government officials (FDA, NIH, etc), and industry scientists met to evaluate the current status of medication adherence and provide recommendations for improving outcomes. Below, we review the magnitude of the problem of medication adherence, prevalence, impact, and cost. We then summarize proven effective approaches and conclude with a discussion of recommendations to address this growing and significant public health issue of medication non adherence. PMID:21884856

  20. Family interaction and treatment adherence after stroke.

    PubMed

    Evans, R L; Bishop, D S; Matlock, A L; Stranahan, S; Smith, G G; Halar, E M

    1987-08-01

    Caregivers of 60 stroke patients were assessed five months after patient discharge from a stroke care unit to determine the relationship between family function and poststroke treatment adherence. Areas of family interaction which were significantly related to ratings of treatment adherence included problem solving, communication, and affective involvement. Better functioning families were consistently high on signs of treatment adherence. Findings suggest that families with specific dysfunction may not be as capable of helping patients comply with rehabilitation efforts as families who function more effectively. Thorough family assessment to identify which areas of family interaction are most problematic in relation to adherence issues is recommended. PMID:3619615

  1. Electrochemical characterization of chromia- and alumina-forming nickel-based superalloys in molten silicates

    NASA Astrophysics Data System (ADS)

    Abdullah, Tuti Katrina; Petitjean, Carine; Panteix, Pierre-Jean; Mathieu, Stéphane; Rapin, Christophe; Vilasi, Michel; Hussain, Zuhailawati; Rahim, Afidah Abdul

    2016-01-01

    A comparison of the corrosion behaviour of simplified chromia- and alumina-forming alloys (Ni-30Cr and Ni-8Al-28Cr) in molten glass is performed via electrochemical methods. A pre-oxidation treatment in air prior to immersion ensured the formation of a 2-μm-thick oxide scale of Cr2O3 or Al2O3. The lifetime of Ni-30Cr depended on the competition between the oxide growth and its dissolution in the melt. For Ni-8Al-28Cr, the high solubility of alumina in the melt studied here led to severe aluminium loss in a few minutes and clearly demonstrated the higher efficiency of chromia-forming alloys for molten glass applications.

  2. Direct Visualization of the Hydration Layer on Alumina Nanoparticles with the Fluid Cell STEM in situ

    PubMed Central

    Firlar, Emre; Çınar, Simge; Kashyap, Sanjay; Akinc, Mufit; Prozorov, Tanya

    2015-01-01

    Rheological behavior of aqueous suspensions containing nanometer-sized powders is of relevance to many branches of industry. Unusually high viscosities observed for suspensions of nanoparticles compared to those of micron size powders cannot be explained by current viscosity models. Formation of so-called hydration layer on alumina nanoparticles in water was hypothesized, but never observed experimentally. We report here on the direct visualization of aqueous suspensions of alumina with the fluid cell in situ. We observe the hydration layer formed over the particle aggregates and show that such hydrated aggregates constitute new particle assemblies and affect the flow behavior of the suspensions. We discuss how these hydrated nanoclusters alter the effective solid content and the viscosity of nanostructured suspensions. Our findings elucidate the source of high viscosity observed for nanoparticle suspensions and are of direct relevance to many industrial sectors including materials, food, cosmetics, pharmaceutical among others employing colloidal slurries with nanometer-scale particles. PMID:25996055

  3. Microstructural and Mechanical Characterization of Actively Brazed Alumina Specimens

    SciTech Connect

    Hosking, F.M.; Cadden, C.H.; Stephens, J.J.; Glass, S.J.; Yang, N.Y.C.; Vianco, P.V.; Walker, C.A.

    1999-08-26

    Alumina (94 and 99.8% grade compositions) was brazed directly to itself with gold-based active brazing alloys (ABA's) containing vanadium additions of 1,2 and 3 weight percent. The effects of brazing conditions on the joint properties were investigated. Wetting behavior, interfacial reactions, microstructure, hermeticity and tensile strength were determined. Wetting was fair to good for the ABA and base material combinations. Microanalysis identified a discontinuous Al-V-O spinel reaction product at the alumina-braze interface. Tensile strength results for 94% alumina were uniformly good and generally not sensitive to the vanadium concentration, with tensile values of 85-105 MPa. There was more variability in the 99.8% alumina strength results, with values ranging from 25-95 MPa. The highest vanadium concentration (3 wt. %) yielded the highest joint strength for the brazed 99.8% alumina. Failures in the 99.8% alumina samples occurred at the braze-alumina interface, while the 94% alumina specimens exhibited fracture of the ceramic substrate.

  4. Dynamic compressive and tensile strengths of spark plasma sintered alumina

    NASA Astrophysics Data System (ADS)

    Girlitsky, I.; Zaretsky, E.; Kalabukhov, S.; Dariel, M. P.; Frage, N.

    2014-06-01

    Fully dense submicron grain size alumina samples were manufactured from alumina nano-powder using Spark Plasma Sintering and tested in two kinds of VISAR-instrumented planar impact tests. In the first kind, samples were loaded by 1-mm tungsten impactors, accelerated to a velocity of about 1 km/s. These tests were aimed at studying the Hugoniot elastic limit (HEL) of Spark Plasma Sintering (SPS)-processed alumina and the decay, with propagation distance, of the elastic precursor wave. In the tests of the second kind, alumina samples of 3-mm thickness were loaded by 1-mm copper impactors accelerated to 100-1000 m/s. These tests were aimed at studying the dynamic tensile (spall) strength of the alumina specimens. The tensile fracture of the un-alloyed alumina shows a monotonic decline of the spall strength with the amplitude of the loading stress pulse. Analysis of the decay of the elastic precursor wave allowed determining the rate of the irreversible (inelastic) strains in the SPS-processed alumina at the initial stages of the shock-induced inelastic deformation and to clarify the mechanisms responsible for the deformation. The 1-% addition of Cr2O3 decreases the HEL of the SPS-processed alumina by 5-% and its spall strength by 50% but barely affects its static properties.

  5. Dynamic compressive and tensile strengths of spark plasma sintered alumina

    SciTech Connect

    Girlitsky, I.; Zaretsky, E.; Kalabukhov, S.; Dariel, M. P.; Frage, N.

    2014-06-28

    Fully dense submicron grain size alumina samples were manufactured from alumina nano-powder using Spark Plasma Sintering and tested in two kinds of VISAR-instrumented planar impact tests. In the first kind, samples were loaded by 1-mm tungsten impactors, accelerated to a velocity of about 1 km/s. These tests were aimed at studying the Hugoniot elastic limit (HEL) of Spark Plasma Sintering (SPS)-processed alumina and the decay, with propagation distance, of the elastic precursor wave. In the tests of the second kind, alumina samples of 3-mm thickness were loaded by 1-mm copper impactors accelerated to 100–1000 m/s. These tests were aimed at studying the dynamic tensile (spall) strength of the alumina specimens. The tensile fracture of the un-alloyed alumina shows a monotonic decline of the spall strength with the amplitude of the loading stress pulse. Analysis of the decay of the elastic precursor wave allowed determining the rate of the irreversible (inelastic) strains in the SPS-processed alumina at the initial stages of the shock-induced inelastic deformation and to clarify the mechanisms responsible for the deformation. The 1-% addition of Cr{sub 2}O{sub 3} decreases the HEL of the SPS-processed alumina by 5-% and its spall strength by 50% but barely affects its static properties.

  6. Process for the recovery of alumina from fly ash

    DOEpatents

    Murtha, M.J.

    1983-08-09

    An improvement in the lime-sinter process for recovering alumina from pulverized coal fly ash is disclosed. The addition of from 2 to 10 weight percent carbon and sulfur to the fly ash-calcium carbonate mixture increase alumina recovery at lower sintering temperatures.

  7. 40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... nanoparticles (generic). 721.10120 Section 721.10120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical... as siloxane modified alumina nanoparticles (PMN P-05-687) is subject to reporting under this...

  8. 40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... nanoparticles (generic). 721.10120 Section 721.10120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical... as siloxane modified alumina nanoparticles (PMN P-05-687) is subject to reporting under this...

  9. Scales

    ScienceCinema

    Murray Gibson

    2010-01-08

    Musical scales involve notes that, sounded simultaneously (chords), sound good together. The result is the left brain meeting the right brain ? a Pythagorean interval of overlapping notes. This synergy would suggest less difference between the working of the right brain and the left brain than common wisdom would dictate. The pleasing sound of harmony comes when two notes share a common harmonic, meaning that their frequencies are in simple integer ratios, such as 3/2 (G/C) or 5/4 (E/C).

  10. Scales

    SciTech Connect

    Murray Gibson

    2007-04-27

    Musical scales involve notes that, sounded simultaneously (chords), sound good together. The result is the left brain meeting the right brain — a Pythagorean interval of overlapping notes. This synergy would suggest less difference between the working of the right brain and the left brain than common wisdom would dictate. The pleasing sound of harmony comes when two notes share a common harmonic, meaning that their frequencies are in simple integer ratios, such as 3/2 (G/C) or 5/4 (E/C).

  11. Determination and evaluation of organic balances of alumina refineries

    SciTech Connect

    Solymar, K.; Gimpel-Kazar, M.; Molnar, E.

    1996-10-01

    The adequate measures to control the organic level and especially that of humates and oxalate need the determination and evaluation of the organic balance of the given alumina plant. The organic materials of the different alumina refineries have special compositions, therefore it is very difficult and limited to draw general and common conclusions for all alumina refineries concerning the role and control of organics. The methodology of the determination of the organic balance of an alumina plant will be discussed. The qualitative and quantitative determination of organic materials has been performed by means of gas-chromatography of the esterized organic materials. The organic balances of three different alumina refineries will be compared and evaluated relating to the total organic and oxalate contents.

  12. Morphology and transmittance of porous alumina on glass substrate

    NASA Astrophysics Data System (ADS)

    Peitao, Guo; Zhilin, Xia; Yiyu, Xue; Caihua, Huang; Lixin, Zhao

    2011-02-01

    The porous optical film has higher threshold of laser-induced damage than densified films, for the study of mechanism of laser-induced damage of porous optical film with ordered pore structure. Porous anodic alumina (PAA) film with high transmittance on glass substrate has been prepared. Aluminum film was deposited on glass substrate by means of resistance and electron beam heat (EBH) evaporation. Porous alumina was prepared in oxalic acid solution under different anodizing conditions. At normal incidence, the optical transmittance spectrum over 300-1000 nm spectra region was obtained by spectrophotometer. SEM was introduced to analysis the morphology of the porous alumina film. The pore aperture increased with the increase of anodizing voltage, which resulted in a rapid decrease of the pore concentration and the optical thickness of porous alumina film. Damage morphology of porous alumina film is found to be typically defects initiated, and the defect is the pore presented on the film.

  13. The mineralogy of bauxite for producing smelter-grade alumina

    NASA Astrophysics Data System (ADS)

    Authier-Martin, M.; Forte, G.; Ostap, S.; See, J.

    2001-12-01

    Aluminum-producing companies rely on low-cost, high-purity, smelter-grade alumina (aluminum oxide), and alumina production utilizes the bulk of bauxites mined world-wide. The mineralogy of the bauxites has a significant impact on the operation of the Bayer process for alumina production. Typically, the Bayer process produces smelter-grade alumina of 99.5% Al2O3, starting from bauxite containing 30% to 60% Al2O3. The main objective of the Bayer process is to extract the maximum amount of aluminum from the bauxite at as high an aluminate concentration in solution as possible, while limiting any troublesome side reactions. Only with a better understanding of the chemistry of the mineral species and a strict control of the operating/processing conditions can the Bayer process produce efficiently, a low cost, high-quality alumina with minimum detrimental environmental impact.

  14. Thermal Conductivity of Alumina-reinforced Zirconia Composites

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.

    2005-01-01

    10-mol% yttria-stabilized zirconia (10SZ) - alumina composites containing 0-30 mol% alumina were fabricated by hot pressing at 1500 C in vacuum. Thermal conductivity was determined at various temperatures using a steady-state laser heat flux technique. Thermal conductivity of the composites increased with increase in alumina content. Composites containing 0, 5, and 10-mol% alumina did not show any change in thermal conductivity with temperature. However, those containing 20 and 30-mol% alumina showed a decrease in thermal conductivity with increase in temperature. The measured values of thermal conductivity were in good agreement with those calculated from the Maxwell-Eucken model where one phase is uniformly dispersed within a second major continuous phase.

  15. Biological Sex, Adherence to Traditional Gender Roles, and Attitudes toward Persons with Mental Illness: An Exploratory Investigation.

    ERIC Educational Resources Information Center

    Hinkelman, Lisa; Granello, Darcy Haag

    2003-01-01

    Undergraduate students responded to the Community Attitudes toward the Mentally Ill (CAMI) questionnaire and the Hypergender Ideology Scale, which measures the degree to which they adhered to traditional gender roles. It was determined that strict gender-role adherence, rather than biological sex accounted for the variance in CAMI scores.…

  16. Adherence of sputtered titanium carbides

    NASA Technical Reports Server (NTRS)

    Brainard, W. A.; Wheeler, D. R.

    1979-01-01

    The study searches for interface treatment that would increase the adhesion of TiC coating to nickel- and titanium-base alloys. Rene 41 (19 wt percent Cr, 11 wt percent Mo, 3 wt percent Ti, balance Ni) and Ti-6Al-4V (6 wt percent Al, 4 wt percent V, balance Ti) are considered. Adhesion of the coatings is evaluated in pin-and disk friction tests. The coatings and interface regions are examined by X-ray photoelectron spectroscopy. Results suggest that sputtered refractory compound coatings adhere best when a mixed compound of coating and substrate metals is formed in the interfacial region. The most effective type of refractory compound interface appears to depend on both substrate and coating material. A combination of metallic interlayer deposition and mixed compound interface formation may be more effective for some substrate coating combinations than either alone.

  17. Properties of Transition Metal Doped Alumina

    NASA Astrophysics Data System (ADS)

    Nykwest, Erik; Limmer, Krista; Brennan, Ray; Blair, Victoria; Ramprasad, Rampi

    Crystallographic texture can have profound effects on the properties of a material. One method of texturing is through the application of an external magnetic field during processing. While this method works with highly magnetic systems, doping is required to couple non-magnetic systems with the external field. Experiments have shown that low concentrations of rare earth (RE) dopants in alumina powders have enabled this kind of texturing. The magnetic properties of RE elements are directly related to their f orbital, which can have as many as 7 unpaired electrons. Since d-block elements can have as many as 5 unpaired electrons the effects of substitutional doping of 3d transition metals (TM) for Al in alpha (stable) and theta (metastable) alumina on the local structure and magnetic properties, in addition to the energetic cost, have been calculated by performing first-principles calculations based on density functional theory. This study has led to the development of general guidelines for the magnetic moment distribution at and around the dopant atom, and the dependence of this distribution on the dopant atom type and its coordination environment. It is anticipated that these findings can aid in the selection of suitable dopants help to guide parallel experimental efforts. This project was supported in part by an internship at the Army Research Laboratory, administered by the Oak Ridge Institute for Science and Education, along with a grant of computer time from the DoD High Performance Computing Modernization Program.

  18. Combination for electrolytic reduction of alumina

    DOEpatents

    Brown, Craig W.; Brooks, Richard J.; Frizzle, Patrick B.; Juric, Drago D.

    2002-04-30

    An electrolytic bath for use during the electrolytic reduction of alumina to aluminum. The bath comprises molten electrolyte having the following ingredients: AlF.sub.3 and at least one salt selected from the group consisting of NaF, KF, and LiF; and about 0.004 wt. % to about 0.2 wt. %, based on total weight of the molten electrolyte, of at least one transition metal or at least one compound of the metal or both. The compound is, a fluoride; oxide, or carbonate. The metal is nickel, iron, copper, cobalt, or molybdenum. The bath is employed in a combination including a vessel for containing the bath and at least one non-consumable anode and at least one dimensionally stable cathode in the bath. Employing the instant bath during electrolytic reduction of alumina to aluminum improves the wetting of aluminum on a cathode by reducing or eliminating the formation of non-metallic deposits on the cathode.

  19. Parsing abnormal grain growth in specialty aluminas

    NASA Astrophysics Data System (ADS)

    Lawrence, Abigail Kremer

    Grain growth in alumina is strongly affected by the impurities present in the material. Certain impurity elements are known to have characteristic effects on abnormal grain growth in alumina. Specialty alumina powders contain multiple impurity species including MgO, CaO, SiO2, and Na 2O. In this work, sintered samples made from alumina powders containing various amounts of the impurities in question were characterized by their grain size and aspect ratio distributions. Multiple quantitative methods were used to characterize and classify samples with varying microstructures. The grain size distributions were used to partition the grain size population into subpopulations depending on the observed deviation from normal behavior. Using both grain size and aspect ratio a new visual representation for a microstructure was introduced called a morphology frequency map that gives a fingerprint for the material. The number of subpopulations within a sample and the shape of the distribution on the morphology map provided the basis for a classification scheme for different types of microstructures. Also using the two parameters a series of five metrics were calculated that describe the character of the abnormal grains in the sample, these were called abnormal character values. The abnormal character values describe the fraction of grains that are considered abnormal, the average magnitude of abnormality (including both grain size and aspect ratio), the average size, and variance in size. The final metric is the correlation between grain size and aspect ratio for the entire population of grains. The abnormal character values give a sense of how different from "normal" the sample is, given the assumption that a normal sample has a lognormal distribution of grain size and a Gaussian distribution of aspect ratios. In the second part of the work the quantified measures of abnormality were correlated with processing parameters such as composition and heat treatment conditions. A

  20. Final report on the application of chaos theory to an alumina sensor for aluminum reduction cells

    SciTech Connect

    Williford, R.E.; Windisch, C.F. Jr.

    1992-03-01

    Four chaos-related digital signal analysis (DSA) methods were applied to the analysis of voltage and current signals collected from aluminum electrolysis cells. Two separate data bases were analyzed: bench-scale laboratory experiments and a pilot-scale test. The objective was to assess the feasibility of using these types of data and analysis methods as the basis for a non-intrusive sensor to measure the alumina content in the electrolysis bath. This was the first time chaos theory approaches have been employed to analyze aluminum electrolysis cells.

  1. Factors associated with adherence to highly active antiretroviral therapy in homeless or unstably housed adults living with HIV.

    PubMed

    Royal, Scott W; Kidder, Daniel P; Patrabansh, Satyendra; Wolitski, Richard J; Holtgrave, David R; Aidala, Angela; Pals, Sherri; Stall, Ron

    2009-04-01

    The aim of this study is to investigate adherence to highly active antiretroviral therapy (HAART) in persons living with HIV/AIDS (PLWHA) who are homeless or unstably housed. We evaluated homeless or unstably housed PLWHA (n=644) in three US cities were enrolled in the Housing and Health Study. Using baseline data and controlling for gender, race, age, and education, we examined associations between self-reported two- and Seven-day adherence and access to healthcare, mental health, substance use, and attitudes toward HIV medical therapy. Of the 644 participants, 358 (55%) were currently on HAART. For two-day adherence, 280 (78%) reported missing no prescribed doses (100% adherence), and for seven-day adherence, 291 (81%) reported > or =90% adherence. Logistic regression analyses indicated being younger, not having health insurance, and drug use were associated with missing > or =1 dose over the past two days. Scoring lower on SF-36 mental component summary scale and having greater risk of depression (CES-D) and stress (Perceived Stress Scale) were associated with poorer adherence for both two- and seven-day outcomes. Negative attitudes toward HIV treatment were also associated with lower adherence. Adherence to HIV medications in this population is similar to other groups. Coexisting problems of access to healthcare, higher risk of mental health problems, along with poorer attitudes toward treatment are associated with increased likelihood of missing doses. Comprehensive models of HIV care that include a continuum of medical and social services are essential for treating this population. PMID:19401865

  2. A study of treatment adherence and quality of life among adults with chronic urticaria in Singapore

    PubMed Central

    Koh, Li Jia; Toh, Matthias Paul Han Sim; Aw, Derrick Chen Wee

    2015-01-01

    Background Chronic urticaria is a common skin condition that causes significant impact on patient's quality of life. Objective The purpose of the study was to assess adherence to therapy and quality of life of patients with chronic urticaria. We also aimed to study the relationship of medication adherence and quality of life of patients with chronic urticaria. Methods A cross sectional study was conducted with 103 patients from the dermatology clinic of National University Hospital, Singapore. Patients with chronic urticaria were asked to fill out a questionnaire for assessment of adherence to therapy and quality of life. We used the Morisky 8-Item Medication Adherence Scale to categorize adherence as high, medium, low. For assessment of quality of life, we used the validated chronic urticaria quality of life questionnaire (CU-Q2oL) by Bairadani et al. Results The highest median scores for the items measuring quality of life were interference with sleep and pruritus. We also observed that the majority of patients (71.9%) had low adherence to medical therapy. No difference in adherence was noted in patients on once daily medication or more frequent dosing. There was no significant difference in the quality of life among patients with low and medium adherence to therapy. Conclusion Quality of life of patients with chronic urticaria does not depend on the patients' adherence to medications. Dosing frequency does not affect adherence in our study population. It is also important to recognize the symptoms and issues most affecting quality of life of patients with chronic urticaria, so as to improve overall management. PMID:26539401

  3. Adherence to Pharmacotherapy and Medication-Related Beliefs in Patients with Hypertension in Lima, Peru

    PubMed Central

    Miranda, J. Jaime; Diez-Canseco, Francisco; Malaga, German

    2014-01-01

    Objective To characterize adherence to pharmacological medication and beliefs towards medication in a group of patients with hypertension in a large national hospital. Materials and Methods Cross-sectional survey among patients with hypertension attending the outpatient clinic of a large national hospital. Exposure of interest was the patient's beliefs towards general medication and antihypertensive drugs, i.e. beliefs of harm, overuse, necessity and concern, measured using the Beliefs about Medication questionnaire. Main outcome was adherence measured using the Morisky Medication Adherence Scale-8. Multivariate analysis was conducted using Poisson distribution logistic regression, prevalence ratios and 95% confidence intervals were calculated. Results Data from 115 participants, 67% females and mean age 62.7 years were analyzed. Low adherence was found in 57.4%. Highest scores were on the ideas of necessity and one of the most rated statements was “physicians would prescribe less medication if they spent more time with patients”. Beliefs of harm about medications and concerns about antihypertensive drugs were higher in the low adherence group (p<0.01). Those who scored higher on ideas of harm were 52% less likely of being high adherents (PR 0.48; 95% CI 0.25–0.93) and those with higher scores on concerns were 41% less likely of being high adherents (PR 0.59; 95% CI 0.39–0.91). Patients whose ideas of necessity outweighed their concerns were more likely to be adherent (PR 2.65; 95% CI 1.21–5.81). Conclusions Low adherence to antihypertensive medication is common. High scores on ideas of harm, concern and a high necessity-concern differential were predictors of medication adherence. PMID:25470372

  4. Psychological Determinants of Adolescent Exercise Adherence.

    ERIC Educational Resources Information Center

    Douthitt, Vicki L.

    1994-01-01

    High school physical education students completed questionnaires which represented four psychological variables, and one physical activity variable (exercise adherence) in classroom setting (n=132) and in summer setting (n=110). Found Perceived Romantic Appeal predictive of male exercise adherence and Perceived Athletic Competency, Perceived…

  5. Predicting asthma exacerbations employing remotely monitored adherence.

    PubMed

    Killane, Isabelle; Sulaiman, Imran; MacHale, Elaine; Breathnach, Aoife; Taylor, Terence E; Holmes, Martin S; Reilly, Richard B; Costello, Richard W

    2016-03-01

    This Letter investigated the efficacy of a decision-support system, designed for respiratory medicine, at predicting asthma exacerbations in a multi-site longitudinal randomised control trial. Adherence to inhaler medication was acquired over 3 months from patients with asthma employing a dose counter and a remote monitoring adherence device which recorded participant's inhaler use: n = 184 (23,656 audio files), 61% women, age (mean ± sd) 49.3 ± 16.4. Data on occurrence of exacerbations was collected at three clinical visits, 1 month apart. The relative risk of an asthma exacerbation for those with good and poor adherence was examined employing a univariate and multivariate modified Poisson regression approach; adjusting for age, gender and body mass index. For all months dose counter adherence was significantly (p < 0.01) higher than remote monitoring adherence. Overall, those with poor adherence had a 1.38 ± 0.34 and 1.42 ± 0.39 (remotely monitored) and 1.25 ± 0.32 and 1.18 ± 0.31 (dose counter) higher relative risk of an exacerbation in model 1 and model 2, respectively. However, this was not found to be statistically significantly different. Remotely monitored adherence holds important clinical information and future research should focus on refining adherence and exacerbation measures. Decision-support systems based on remote monitoring may enhance patient-physician communication, possibly reducing preventable adverse events. PMID:27222733

  6. A Review of Treatment Adherence Measurement Methods

    ERIC Educational Resources Information Center

    Schoenwald, Sonja K.; Garland, Ann F.

    2013-01-01

    Fidelity measurement is critical for testing the effectiveness and implementation in practice of psychosocial interventions. Adherence is a critical component of fidelity. The purposes of this review were to catalogue adherence measurement methods and assess existing evidence for the valid and reliable use of the scores that they generate and the…

  7. Adherence to Antiretroviral Therapy and Virologic Failure

    PubMed Central

    Bezabhe, Woldesellassie M.; Chalmers, Leanne; Bereznicki, Luke R.; Peterson, Gregory M.

    2016-01-01

    Abstract The often cited need to achieve ≥95% (nearly perfect) adherence to antiretroviral therapy (ART) for successful virologic outcomes in HIV may present a barrier to initiation of therapy in the early stages of HIV. This meta-analysis synthesized 43 studies (27,905 participants) performed across >26 countries, to determine the relationship between cut-off point for optimal adherence to ART and virologic outcomes. Meta-analysis was performed using a random-effect model to calculate pooled odds ratios with corresponding 95% confidence intervals. The mean rate of patients reporting optimal adherence was 63.4%. Compared with suboptimal adherence, optimal adherence was associated with a lower risk of virologic failure (0.34; 95% CI: 0.26–0.44). There were no significant differences in the pooled odds ratios among different optimal adherence thresholds (≥98–100%, ≥95%, ≥80–90%). Study design (randomized controlled trial vs observational study) (regression coefficient 0.74, 95% CI: 0.04–1.43, P < 0.05) and study region (developing vs developed countries; regression coefficient 0.56, 95% CI: 0.01–1.12, P < 0.05) remained as independent predictors of between-study heterogeneity, with more patients with optimal adherence from developing countries or randomized controlled trials experiencing virologic failure. The threshold for optimal adherence to achieve better virologic outcomes appears to be wider than the commonly used cut-off point (≥95% adherence). The cut-off point for optimal adherence could be redefined to a slightly lower level to encourage the prescribing ART at an early stage of HIV infection. PMID:27082595

  8. Vaccine production: upstream processing with adherent or suspension cell lines.

    PubMed

    Genzel, Yvonne; Rödig, Jana; Rapp, Erdmann; Reichl, Udo

    2014-01-01

    The production of viral vaccines in cell culture can be accomplished with primary, diploid, or continuous (transformed) cell lines. Each cell line, each virus type, and each vaccine preparation require the specific design of upstream and downstream processing. Media have to be selected as well as production vessels, cultivation conditions, and modes of operation. Many viruses only replicate to high titers in adherently growing cells, but similar to processes established for recombinant protein production, an increasing number of suspension cell lines is being evaluated for future use. Here, we describe key issues to be considered for the establishment of large-scale virus production in bioreactors. As an example upstream processing of cell culture-derived influenza virus production is described in more detail for adherently growing and for suspension cells. In particular, use of serum-containing, serum-free, and chemically defined media as well as choice of cultivation vessel are considered. PMID:24297427

  9. Terbium luminescence in alumina xerogel fabricated in porous anodic alumina matrix under various excitation conditions

    SciTech Connect

    Gaponenko, N. V.; Kortov, V. S.; Orekhovskaya, T. I.; Nikolaenko, I. A.; Pustovarov, V. A.; Zvonarev, S. V.; Slesarev, A. I.; Prislopski, S. Ya.

    2011-07-15

    Terbium-doped alumina xerogel layers are synthesized by the sol-gel method in pores of a porous anodic alumina film 1 {mu}m thick with a pore diameter of 150-180 nm; the film is grown on a silicon substrate. The fabricated structures exhibit terbium photoluminescence with bands typical of trivalent terbium terms. Terbium X-ray luminescence with the most intense band at 542 nm is observed for the first time for such a structure. Morphological analysis of the structure by scanning electron microscopy shows the presence of xerogel clusters in pore channels, while the main pore volume remains unfilled and pore mouths remain open. The data obtained confirm the promising applications of fabricated structures for developing matrix converters of X-rays and other ionizing radiations into visible light. The possibilities of increasing luminescence intensity in the matrix converter are discussed.

  10. On the material and the tribology of alumina-alumina couplings for hip joint prostheses.

    PubMed

    Walter, A

    1992-09-01

    The yearly sphericity deviation ranged from 0.03 mu to 3.7 mm in 48 retrieved implants with alumina--alumina bearing balls and cups. Excessive amounts of wear are predominantly design dependent or caused by malalignment. But the abrasion phenomena occurring in the cup centers and in the corresponding ball areas are related to unfavorable function zones. The influence of the lubricating gap geometry as studied in laboratory tests shows the form of sphericity deviations to be of decisive importance for wear and friction, if extended over small angles. Then, the contact stresses attributable to the actual effective curvatures of the bearing exceed the resistance to abrasion of the material under boundary lubrication conditions. There are remarkable differences between the early and actual material quality. Based on the state of knowledge of material aspects of wear criteria for the optimization of material and design, promising tolerable wear rates may be achieved. PMID:1516324

  11. Processing and mechanical characterization of alumina laminates

    NASA Astrophysics Data System (ADS)

    Montgomery, John K.

    2002-08-01

    Single-phase ceramics that combine property gradients or steps in monolithic bodies are sought as alternatives to ceramic composites made of dissimilar materials. This work describes novel processing methods to produce stepped-density (or laminated) alumina single-phase bodies that maintain their mechanical integrity. One arrangement consists of a stiff, dense bulk material with a thin, flaw tolerant, porous exterior layer. Another configuration consists of a lightweight, low-density bulk material with a thin, hard, wear resistant exterior layer. Alumina laminates with strong interfaces have been successfully produced in this work using two different direct-casting processes. Gelcasting is a useful near-net shape processing technique that has been combined with several techniques, such as reaction bonding of aluminum oxide and the use of starch as a fugative filler, to successfully produced stepped-density alumina laminates. The other direct casting process that has been developed in this work is thermoreversible gelcasting (TRG). This is a reversible gelation process that has been used to produce near-net shape dense ceramic bodies. Also, individual layers can be stacked together and heated to produce laminates. Bilayer laminate samples were produced with varied thickness of porous and dense layers. It was shown that due to the difference in modulus and hardness, transverse cracking is found upon Hertzian contact when the dense layer is on the exterior. In the opposite arrangement, compacted damage zones formed in the porous material and no damage occurred in the underlying dense layer. Flaw tolerant behavior of the porous exterior/dense underlayer was examined by measuring biaxial strength as a function of Vickers indentation load. It was found that the thinnest layer of porous material results in the greatest flaw tolerance. Also, higher strength was exhibited at large indentation loads when compared to dense monoliths. The calculated stresses on the surfaces

  12. A Brief Adherence Intervention that Improved Glycemic Control: Mediation by Patterns of Adherence

    PubMed Central

    de Vries McClintock, Heather F.; Morales, Knashawn H.; Small, Dylan S.; Bogner, Hillary R.

    2014-01-01

    This study examined whether longitudinal adherence profiles mediated the relationship between a brief adherence intervention and glycemic control among patients with Type 2 diabetes. Adherence was assessed using the Medication Event Monitoring System (MEMS). Longitudinal analysis via growth curve mixture modeling was carried out to classify patients according to patterns of adherence to oral hypoglycemic agents. Hemoglobin A1c (HbA1c) assays were used to measure glycemic control as the clinical outcome. Across the whole sample, longitudinal adherence profiles mediated 35.2% (13.2%, 81.0%) of the effect of a brief adherence intervention on glycemic control (from odds ratio (OR) = 8.48, 95% CI (3.24, 22.2) to 4.00, 95% CI (1.34, 11.93)). Our results suggest that patients in the intervention had better glycemic control largely due to their greater likelihood of adherence to oral hypoglycemic agents. PMID:24913600

  13. Factors associated with suboptimal adherence to antiretroviral therapy in Asia

    PubMed Central

    Jiamsakul, Awachana; Kumarasamy, Nagalingeswaran; Ditangco, Rossana; Li, Patrick CK; Phanuphak, Praphan; Sirisanthana, Thira; Sungkanuparph, Somnuek; Kantipong, Pacharee; Lee, Christopher KC; Mustafa, Mahiran; Merati, Tuti; Kamarulzaman, Adeeba; Singtoroj, Thida; Law, Matthew

    2014-01-01

    Introduction Adherence to antiretroviral therapy (ART) plays an important role in treatment outcomes. It is crucial to identify factors influencing adherence in order to optimize treatment responses. The aim of this study was to assess the rates of, and factors associated with, suboptimal adherence (SubAdh) in the first 24 months of ART in an Asian HIV cohort. Methods As part of a prospective resistance monitoring study, the TREAT Asia Studies to Evaluate Resistance Monitoring Study (TASER-M) collected patients’ adherence based on the World Health Organization-validated Adherence Visual Analogue Scale. SubAdh was defined in two ways: (i) <100% and (ii) <95%. Follow-up time started from ART initiation and was censored at 24 months, loss to follow-up, death, treatment switch, or treatment cessation for >14 days. Time was divided into four intervals: 0–6, 6–12, 12–18 and 18–24 months. Factors associated with SubAdh were analysed using generalized estimating equations. Results Out of 1316 patients, 32% ever reported <100% adherence and 17% ever reported <95%. Defining the outcome as SubAdh <100%, the rates of SubAdh for the four time intervals were 26%, 17%, 12% and 10%. Sites with an average of >2 assessments per patient per year had an odds ratio (OR)=0.7 (95% confidence interval (CI) (0.55 to 0.90), p=0.006), compared to sites with ≤2 assessments per patient per year. Compared to heterosexual exposure, SubAdh was higher in injecting drug users (IDUs) (OR=1.92, 95% CI (1.23 to 3.00), p=0.004) and lower in homosexual exposure (OR=0.52, 95% CI (0.38 to 0.71), p<0.001). Patients taking a nucleoside transcriptase inhibitor and protease inhibitor (NRTI+PI) combination were less likely to report adherence <100% (OR=0.36, 95% CI (0.20 to 0.67), p=0.001) compared to patients taking an NRTI and non-nucleoside transcriptase inhibitor (NRTI+NNRTI) combination. SubAdh decreased with increasing time on ART (all p<0.001). Similar associations were found with adherence

  14. Fracture of the alumina-bearing couple delta ceramic liner.

    PubMed

    Taheriazam, Afshin; Mohajer, Mohammad Azizbaig; Aboulghasemian, Mansoour; Hajipour, Babak

    2012-01-01

    The fracture rate of third-generation ceramic liners is greatly reduced compared with first- and second-generation liners because of improvements in the design and manufacturing process. Fractures of the alumina-bearing couple are rare for the same reason.This article describes a case of a fracture of an alumina-bearing couple delta ceramic liner without trauma history that was treated with ceramic-on-polyethylene revision total hip arthroplasty. A 57-year-old man was admitted to the hip ward because of an alumina-bearing couple delta ceramic liner fracture. He underwent hip replacement by anterior approach 18 months previously in the same center because of left hip primary osteoarthritis. He received a 54×36-mm modular press-fit cup ceramic alumina-bearing couple delta insert. Probable causes of such fractures are manufacture production failure and edge loading based on cup inclination, but in our patient, inacceptable range of motion, failure of the locking mechanism during implantation insertion, or cracking were possible causes of fracture.Although the fracture rate of third-generation alumina-bearing couples is low, we believe that it may not be possible to eliminate the actual risk of alumina head fracture. Patients should be informed about the potential for this complication before receiving an alumina-bearing couple. PMID:22229622

  15. Essentials of specifications for activated alumina in defluoridation technology.

    PubMed

    Misra, S K

    2006-10-01

    Worldwide, fluoride occurs naturally in some aquifers at concentrations above the WHO guideline values or Bureau of Indian Standards or CPHEEO - MUD - GOI parametric values. Fluoride in excess of the permissible limits in drinking water causes a number of endemic conditions referred to collectively as "fluorosis". Endemic fluorosis remains a challenging national health problem in India and Rajasthan is one of the worst affected states in India though a wide range of chemical and physical defluoridation systems were evolved and tried. Still activated alumina is one of the most widely used and liked defluoridation material currently available. Boom in the advanced and versatile alumina technology has opened new vistas to avail the strong potential of selective alumina adsorbents which are application-specific. Non-regenerable and specialty alumina offer tremendous scope to defluoridate drinking water. Indian industries are manufacturing regenerable activated alumina for defluoridation of drinking water. In order to ensure application of an adsorbent, which caters the desired results with minimum interferences, health risks and long service life span, it is inevitable to draw out dimensions which define precisely the attributes of activated alumina. Specifications for activated alumina intended for defluoridation of drinking water, specific operating and performance requirements, and limitations expressed by critical analysis of cardinal characteristics pave way for adoption of acceptable specifications and code of practice at national level. PMID:18179116

  16. Interfacial fracture toughness of alumina/niobium systems

    SciTech Connect

    Stout, M.G. ); O'Dowd, N.P.; Shih, C.F. . Div. of Engineering)

    1991-01-01

    The interfacial fracture toughness of an alumina/niobium composite has been measured as a function of phase angle. The interface was formed by solid-state bonding bulk Coor's AD-999 fine-grain alumina with a commercial purity niobium at 1600{degrees}C for 0.5 hr under a pressure of 10.5 MPa. The alumina/niobium system has a number of features which makes it ideal for an investigation of interfacial fracture toughness. From HREM data we estimate that the width of the interface is no more than 10 atomic planes. Furthermore the thermal expansion coefficients of the two materials differ by less than 5% so residual stresses due to the bonding process are small. Using symmetric and asymmetric four point bend specimens we have measured the fracture toughness of homogenous alumina and that of the alumina/niobium bimaterial in combinations of in-plane shear and tension. The fracture toughness of the homogenous alumina is relatively insensitive to the loading phase. The measured fracture toughness K{sub c} of the interface, however, depended strongly on phase angle. We were unable to obtain valid alumina/niobium interfacial toughness data at negative phase angles as the fracture initiates in the alumina and not at the interface. In symmetric bending at a phase angle {approx}5{degrees}, we measured a nominal interface toughness of 4.0 MPa{radical}m, comparable to the homogeneous alumina. We found that the toughness increased with loading phase angle to a value of K{sub c} {approx} 9 MPa{radical}m at a phase between 25{degrees} and 40{degrees}. Preliminary calculations and experiments suggest that this effect is due to an asymmetric stress distribution, with respect to the interface, and plastic deformation in the niobium. 12 refs., 9 figs., 1 tab.

  17. Scattering and absorption coefficients of silica-doped alumina aerogels.

    PubMed

    Fu, Tairan; Tang, Jiaqi; Chen, Kai; Zhang, Fan

    2016-02-01

    Alumina-based aerogels are especially useful in many applications due to their excellent stability at high temperatures. This study experimentally analyzed the radiative properties of silica-doped alumina aerogels through spectral directional-hemispherical measurements for wavelengths of 0.38-25 μm. The silica-doped alumina aerogel samples were prepared with a 1.4∶1 molar ratio of silica to alumina. A two-flux model was used to describe the radiation propagation in a 1D scattering absorbing sample to derive expressions for the normal-hemispherical transmittances and reflectances based on the transport approximation. The normal-hemispherical transmittances and reflectances were measured at various spectral wavelengths and sample thicknesses using the integrating sphere method. The spectral absorption and transport scattering coefficients of silica-doped alumina aerogels were then determined from the measured normal-hemispherical data. The absorption and transport scattering coefficients of silica-doped alumina aerogels are (0.1  cm-1, 36  cm-1) and (0.1  cm-1, 112  cm-1) for wavelengths of 0.38-8.0 μm. The spectral transport scattering coefficient varies in the opposite direction from the spectral absorption coefficient for various wavelengths. The radiative properties for silica and alumina aerogels were quite different for the absorption coefficient for wavelengths of 2.5-8.0 μm and for the transport scattering coefficient for wavelengths of 0.38-2.5 and 3.5-6.0 μm. The measured radiative properties were used to predict the spectral normal-hemispherical reflectance and transmittance of the silica-doped alumina aerogels for various sample thicknesses and wavelengths. The predicted values do not change for the sample thicknesses greater than a critical value. The analysis provides valuable reference data for alumina aerogels for high-temperature applications. PMID:26836071

  18. Dermal Toxicity of Flake-Like α-Alumina Pigments.

    PubMed

    Kwon, TaeWoo; Seo, HyunJeong; Jang, Seongwan; Lee, Sang-Geun; Park, Sungkyun; Park, Kang Hyun; Youn, BuHyun

    2015-02-01

    Aluminum is one of the most widely used nonferrous metals and an important industrial material, especially for automotive coatings. However, potential toxicity caused by aluminum in humans limits the used of this metal. α-alumina is the most stable form of aluminum in various phases. Although the results of studies evaluating the dermal toxicity of α-alumina remained unclear, this compound can still be used as a pigment in cosmetics for humans. In the current study, we further evaluated the dermal cytotoxic effects of α-alumina on human skin cells and an in vivo mouse model. We also measured the in vitro penetration profile of flake-like α-alumina in porcine skin and assessed the degree of cellular metabolic disorders. Our findings demonstrated that treatment with flake-like α-alumina did not significantly affect cell viability up to 24 h. This compound was found to have a non-penetration profile based on a Franz modified diffusion cell assay. In addition, flake-like α-alumina was not found to induce dermal inflammation as assessed by histology of epidermal architecture, hyperplasia, and the expression of Interleukin-1β and Cyclooxygenase-2. Results of the cellular metabolic disorder assay indicated that flake-like α-alumina does not exert a direct effect on human skin cells. Taken together, our findings provided not only evidence that flake-like α-alumina may serve as a pearlescent pigment in cosmetics but also experimental basis utilizing α-alumina for human application. Our results also obviously provide new insight of the further toxicity study to aluminum based nanoparticles for skin. PMID:26353706

  19. Application of micro-indentation to irradiated alumina and vanadium/alumina joints

    NASA Astrophysics Data System (ADS)

    Hasegawa, A.; Kawamura, Y.; Satou, M.; Abe, K.

    1996-10-01

    The micro-indentation test as a method to introduce interface crack and to investigate the bonding strength of metal/ceramics joints is examined. Micro-indentation test was carried out using Vickers hardness tester at room temperature on joints of poly- or single-crystal alumina and vanadium or vanadium alloys. The vanadium/alumina (V/Al 2O 3) joints, unirradiated and irradiated in FFTF/MOTA in a helium-filled capsule at 693 K, were tested. The irradiation damage of the joint was about 40 dpa. Micro-indentation on the unirradiated joint interface showed several types of deformation and crack propagation behavior depending on the bonding strength of the joints. Irradiation hardening and brittle behavior were observed on the alumina side of the irradiated V/Al 2O 3 joints. Results of micro-indentation test at the V/Al 2O 3 interface showed the possibility of irradiation-induced strengthening of the interface caused by irradiation-induced mixing at the interface.

  20. Is wear debris responsible for failure in alumina-on-alumina implants?

    PubMed Central

    Baldini, Nicola; Ciapetti, Gabriela; Pellacani, Andrea; Giunti, Armando

    2009-01-01

    Background and purpose Ceramic-on-ceramic articulation is an attractive alternative to metal-on-polyethylene (PE) bearings, but little is known about the in vivo effects induced by dissemination of alumina wear debris in the periprosthetic tissues. We hypothesized that wear debris is not the main factor responsible for loosening and failure of the implant but that mechanical problems caused by incorrect surgical technique, prosthetic design, or trauma, may cause instability of the implants and result in production of wear debris. Patients and methods Clinical, radiographic, laboratory, and microbiological data from 30 consecutive patients with failed alumina-on-alumina arthroplasties, 19 with screwed socket and 11 with press-fit socket, were systematically collected and evaluated. Retrieved peri-implant tissues and prosthesis wear were also analyzed. Results and Interpretation Loosening was due to malpositioning, primary mechanical instability, trauma, or infection. Bone stock was generally preserved, even if screwed implants showed higher levels of osteolysis. Variable implant wear and tissue macrophage reaction were present but activation of giant cells/osteoclasts was not induced, and no correlation between histocytic reaction and the level of osteolysis was found. These findings indicate that, in contrast to the situation with metal-on-PE bearings, wear debris and occasional osteolysis were the effect rather than the cause of failure of ceramic-on-ceramic implants, and that press-fit socket fixation was the socket fixation design of preference. PMID:19404796

  1. Microstructural Models of Alumina Nanotubes and Anodic Porous Alumina Film Formed in Sulphuric Acid

    NASA Astrophysics Data System (ADS)

    Pu, Lin; Chen, Zhi-Qiang; Tan, Chao; Yang, Zheng; Zou, Jian-Ping; Bao, Xi-Mao; Feng, Duan; Shi, Yi; Zheng, You-Dou

    2002-03-01

    Electrochemical stepwise anodization of aluminium in dilute sulphuric acid results in the formation of alumina nanotubes (ANTs) due to the hexagonal split of the anodic porous alumina (APA) film along the cell boundaries containing many voids; that is, the ANTs are the completely detached cell of the APA film. The inner diameters of the ANTs are in the range of 10-20 nm, and the aspect ratio (inner diameter/length) of the ANTs can be about 80. The relations found for pore diameter, cell diameter and barrier layer thickness are around 1, 2.7 and 0.85 nm/V, respectively. Transmission electron microscopy (TEM) reveals that the ANT wall has a three-shell structure: an outer shell (metal/oxide interface) consisting of pure alumina oxide, a middle shell of the hydrated oxide or/and hydroxide and an inner shell (oxide/electrolyte interface) of anion incorporated oxide with the thickness ratio of 1:1:2. The structural change of ANTs induced by e-beam irradiation in TEM indicates that the thermal instability of the hydrated oxide or/and hydroxide within the cell wall might be an alternative origin contributing to the self-organization of the cells, leading to a densely packed triangular cell lattice of the APA film.

  2. Alumina-alumina hip replacement in patients younger than 50 years old.

    PubMed

    Sedel, L; Nizard, R S; Kerboull, L; Witvoet, J

    1994-01-01

    From April 1977 to December 1990, 131 total hip arthroplasties were performed on 113 patients younger than 50 years of age (median, 41 years); 64 were men and 49 women. The majority were active people. Sixty-six hips had no previous operations, and 33 had at least one previous arthroplasty. The femoral component was a cemented collared titanium alloy stem, and alumina socket was cemented for 99 hips and press-fit for 32. The mean follow-up period was five years, with 32 hips followed for more than ten years. Revision arthroplasty was considered as a failure. Survivorship analysis depicted a 97.5% rate of survival at five years, an 89.4% rate at ten years, and an 86.2% at 11 years. Nine revisions were performed: one experienced a femoral head rupture after three years, one had bipolar loosening, one experienced femoral cystic formation, and six were revised for acetabular cup loosening, all from the cemented group. Two revisions occurred on the same patient. No stem revision was necessary before ten years. Only one of these revisions was required in patients aged 40 or younger (64 patients). Alumina-alumina friction is an extremely interesting phenomenon in young patients, and could be related to the low wear debris production. PMID:8118972

  3. Variability of erythrocyte and serum lithium levels correlates with therapist treatment adherence efforts and maintenance treatment outcome.

    PubMed

    Taylor, R; Mallinger, A G; Frank, E; Rucci, P; Thase, M E; Kupfer, D J

    2001-02-01

    This study investigated the relationship between psychotherapeutic interventions and pharmacologic measures of pharmacotherapy treatment adherence in patients with bipolar I disorder, as well as the relationship between these measures and treatment outcome. Subjects were participating in an ongoing maintenance treatment study. Audiotaped therapy sessions were rated for frequency of psychotherapeutic interventions related to pharmacotherapy treatment adherence. Pharmacologic measures of medication adherence were compared to the tape ratings as well as to treatment outcome. Variability in log erythrocyte (RBC) lithium-a marker of probable nonadherence to the pharmacotherapy regimen-for individual patients correlated significantly with treatment adherence interventions scale ratings. This marker of nonadherence was significantly related to maintenance treatment outcome, as was variability of the serum lithium level/dose (L/D) ratio; however, no relationship was found between treatment adherence interventions scale ratings and outcome. PMID:11120401

  4. Residual Stress Predictions in Polycrystalline Alumina

    SciTech Connect

    VEDULA,VENKATA R.; GLASS,S. JILL; SAYLOR,DAVID M.; ROHRER,GREGORY S.; CARTER,W. CRAIG; LANGER,STEPHEN A.

    1999-12-13

    Microstructure-level residual stresses arise in polycrystalline ceramics during processing as a result of thermal expansion anisotropy and crystallographic disorientation across the grain boundaries. Depending upon the grain size, the magnitude of these stresses can be sufficiently high to cause spontaneous microcracking during the processing of these materials. They are also likely to affect where cracks initiate and propagate under macroscopic loading. The magnitudes of residual stresses in untextured and textured alumina samples were predicted using object oriented finite (OOF) element analysis and experimentally determined grain orientations. The crystallographic orientations were obtained by electron-backscattered diffraction (EBSD). The residual stresses were lower and the stress distributions were narrower in the textured samples compared to those in the untextured samples. Crack initiation and propagation were also simulated using the Griffith fracture criterion. The grain boundary to surface energy ratios required for computations were estimated using AFM groove measurements.

  5. Compositional characterization of atomic layer deposited alumina

    SciTech Connect

    Philip, Anu; Thomas, Subin; Kumar, K. Rajeev

    2014-01-28

    As the microelectronic industry demands feature size in the order of few and sub nanometer regime, the film composition and other film properties become critical issues and ALD has emerged as the choice of industry. Aluminum oxide is a material with wide applications in electronic and optoelectronic devices and protective and ion barrier layers. Al{sub 2}O{sub 3} is an excellent dielectric because of its large band gap (8.7eV), large band offsets with silicon. We have deposited thin layers of alumina on silicon wafer (p-type) for gate dielectric applications by ALD technique and compositional characterizations of the deposited thin films were done using EDS, XPS and FTIR spectra.

  6. Tensile creep behavior of polycrystalline alumina fibers

    NASA Technical Reports Server (NTRS)

    Yun, H. M.; Goldsby, J. C.

    1993-01-01

    Tensile creep studies were conducted on polycrystalline Nextel 610 and Fiber FP alumina fibers with grain sizes of 100 and 300 nm, respectively. Test conditions were temperatures from 800 to 1050 C and stresses from 60 to 1000 MPa. For both fibers, only a small primary creep portion occurred followed by steady-state creep. The stress exponents for steady-state creep of Nextel 610 and Fiber FP were found to be about 3 and 1, respectively. At lower temperatures, below 1000 C, the finer grained Nextel 610 had a much higher 0.2 percent creep strength for 100 hr than the Fiber FP; while at higher temperatures, Nextel 610 had a comparable creep strength to the Fiber FP. The stress and grain size dependencies suggest Nextel 610 and Fiber FP creep rates are due to grain boundary sliding controlled by interface reaction and Nabarro-Herring mechanisms, respectively.

  7. Crystallography of Alumina-YAG-Eutectic

    NASA Technical Reports Server (NTRS)

    Farmer, Serene C.; Sayir, Ali; Dickerson, Robert M.; Matson, Lawrence E.

    2000-01-01

    Multiple descriptions of the alumina-YAG eutectic crystallography appear in the ceramic literature. The orientation between two phases in a eutectic system has direct impact on residual stress, morphology, microstructural stability, and high temperature mechanical properties. A study to demonstrate that the different crystallographic relationships can be correlated with different growth constraints was undertaken. Fibers produced by Laser-Heated Float Zone (LHFZ) and Edge-defined Film-fed Growth (EFG) were examined. A map of the orientation relationship between Al2O3 and Y3Al5O12 and their relationship to the fiber growth axis as a function of pull rate are presented. Regions in which a single orientation predominates are identified.

  8. Optimized alumina coagulants for water treatment

    SciTech Connect

    Nyman, May D.; Stewart, Thomas A.

    2012-02-21

    Substitution of a single Ga-atom or single Ge-atom (GaAl.sub.12 and GeAl.sub.12 respectively) into the center of an aluminum Keggin polycation (Al.sub.13) produces an optimal water-treatment product for neutralization and coagulation of anionic contaminants in water. GaAl.sub.12 consistently shows .about.1 order of magnitude increase in pathogen reduction, compared to Al.sub.13. At a concentration of 2 ppm, GaAl.sub.12 performs equivalently to 40 ppm alum, removing .about.90% of the dissolved organic material. The substituted GaAl.sub.12 product also offers extended shelf-life and consistent performance. We also synthesized a related polyaluminum chloride compound made of pre-hydrolyzed dissolved alumina clusters of [GaO.sub.4Al.sub.12(OH).sub.24(H.sub.2O).sub.12].sup.7+.

  9. Adherence to Antiretroviral Therapy Among Children Living with HIV in South India.

    PubMed

    Mehta, K; Ekstrand, M L; Heylen, E; Sanjeeva, G N; Shet, A

    2016-05-01

    Adherence to ART, fundamental to treatment success, has been poorly studied in India. Caregivers of children attending HIV clinics in southern India were interviewed using structured questionnaires. Adherence was assessed using a visual analogue scale representing past-month adherence and treatment interruptions >48 h during the past 3 months. Clinical features, correlates of adherence and HIV-1 viral-load were documented. Based on caregiver reports, 90.9 % of the children were optimally adherent. In multivariable analysis, experiencing ART-related adverse effects was significantly associated with suboptimal adherence (p = 0.01). The proportion of children who experienced virological failure was 16.5 %. Virological failure was not linked to suboptimal adherence. Factors influencing virological failure included running out of medications (p = 0.002) and the child refusing to take medications (p = 0.01). Inclusion of drugs with better safety profiles and improved access to care could further enhance outcomes. PMID:26443264

  10. Quality of life, clinical characteristics and treatment adherence of people living with HIV/AIDS1

    PubMed Central

    Silva, Ana Cristina de Oliveira e; Reis, Renata Karina; Nogueira, Jordana Almeida; Gir, Elucir

    2014-01-01

    OBJECTIVES: to assess the quality of life of people living with HIV/AIDS and verify its association with clinical characteristics and treatment adherence. METHOD: cross-sectional study conducted in a hospital in the state of Paraíba, Brazil. A questionnaire was used to collect socio-demographic and clinical data. The quality of life scale proposed by the World Health Organization and a questionnaire to measure treatment adherence were used. RESULTS: of the 314 interviewees, 190 (60.5%) were male, aged 43 years on average, 121 (38.5%) had attended up to five years of schooling, 108 (34.4%) received up to two times the minimum wage, and 112 (35.7%) were on sick leave. In regard to clinical variables, individuals with an undetectable viral load scored higher in all the domains concerning quality of life, with statistically significant differences in three domains. Regarding treatment adherence, 235 (73.8%) presented poor adherence and those who strictly adhered to treatment obtained better scores in quality of life. The results show that quality of life is better among individuals adherent to ART. Supporting people to adhere to the antiretroviral treatment should be a persistent task of healthcare workers and other people participating in the treatment, such as family members and friends. PMID:25591095

  11. Alumina Paste Sublimation Suppression Barrier for Thermoelectric Device

    NASA Technical Reports Server (NTRS)

    Paik, Jong-Ah (Inventor); Caillat, Thierry (Inventor)

    2014-01-01

    Alumina as a sublimation suppression barrier for a Zintl thermoelectric material in a thermoelectric power generation device operating at high temperature, e.g. at or above 1000K, is disclosed. The Zintl thermoelectric material may comprise Yb.sub.14MnSb.sub.11. The alumina may be applied as an adhesive paste dried and cured on a substantially oxide free surface of the Zintl thermoelectric material and polished to a final thickness. The sublimation suppression barrier may be finalized by baking out the alumina layer on the Zintl thermoelectric material until it becomes substantially clogged with ytterbia.

  12. Porous alumina based ordered nanocomposite coating for wear resistance

    NASA Astrophysics Data System (ADS)

    Yadav, Arti; Muthukumar, M.; Bobji, M. S.

    2016-08-01

    Uniformly dispersed nanocomposite coating of aligned metallic nanowires in a matrix of amorphous alumina is fabricated by pulsed electrodeposition of copper into the pores of porous anodic alumina. Uniform deposition is obtained by controlling the geometry of the dendritic structure at the bottom of pores through stepwise voltage reduction followed by mild etching. The tribological behaviour of this nanocomposite coating is evaluated using a ball on flat reciprocating tribometer under the dry contact conditions. The nanocomposite coating has higher wear resistance compared to corresponding porous alumina coating. Wear resistant nanocomposite coating has wide applications especially in protecting the internal surfaces of aluminium internal combustion engines.

  13. Processing of silicon nitride and alumina nanosize powders

    SciTech Connect

    Gonzalez, E.J.; Piermarini, G.; Hockey, B.; Malghan, S.G.

    1995-08-01

    The effects of pressure on the compaction and subsequent processing of nanosize {gamma} alumina powders were studied. A 3 mm diameter piston/cylinder die was used to compact the nanosize powders to pressures of 1 and 2.5 GPa. The green bodies were sintered at temperatures up to 1600{degrees}C. Results show that green body density can be increased by higher compaction pressures. It appears that as a result of the {gamma}-to-{alpha} transformation in alumina, higher green density does not necessarily produce a higher density sintered alumina body. The microstructures of the sintered bodies are described in terms of porosity and phase content.

  14. Alumina as a dopant in optical fiber by OVD

    NASA Astrophysics Data System (ADS)

    Wang, Ji

    2014-08-01

    Alumina is an indispensable dopant in modern optical fiber technology, particularly due to its important role played in the recent developments of optical fiber amplifiers and high-power fiber lasers over the last decade or so, which have revolutionized the telecommunication systems, and the industrial laser landscapes, respectively. In this paper, Alumina-doped optical fibers advanced through the outside vapor deposition process and their key attributes in the respective applications are reviewed, with Alumina both as a sole dopant for its potential use in the low-loss transmission lines and as a co-dopant for active use in the high-brightness, high-power fiber laser applications.

  15. Aluminum-Alloy-Matrix/Alumina-Reinforcement Composites

    NASA Technical Reports Server (NTRS)

    Kashalikar, Uday; Rozenoyer, Boris

    2004-01-01

    Isotropic composites of aluminum-alloy matrices reinforced with particulate alumina have been developed as lightweight, high-specific-strength, less-expensive alternatives to nickel-base and ferrous superalloys. These composites feature a specific gravity of about 3.45 grams per cubic centimeter and specific strengths of about 200 MPa/(grams per cubic centimeter). The room-temperature tensile strength is 100 ksi (689 MPa) and stiffness is 30 Msi (206 GPa). At 500 F (260 C), these composites have shown 80 percent retention in strength and 95 percent retention in stiffness. These materials also have excellent fatigue tolerance and tribological properties. They can be fabricated in net (or nearly net) sizes and shapes to make housings, pistons, valves, and ducts in turbomachinery, and to make structural components of such diverse systems as diesel engines, automotive brake systems, and power-generation, mining, and oil-drilling equipment. Separately, incorporation of these metal matrix composites within aluminum gravity castings for localized reinforcement has been demonstrated. A composite part of this type can be fabricated in a pressure infiltration casting process. The process begins with the placement of a mold with alumina particulate preform of net or nearly net size and shape in a crucible in a vacuum furnace. A charge of the alloy is placed in the crucible with the preform. The interior of the furnace is evacuated, then the furnace heaters are turned on to heat the alloy above its liquidus temperature. Next, the interior of the furnace is filled with argon gas at a pressure about 900 psi (approximately equal to 6.2 MPa) to force the molten alloy to infiltrate the preform. Once infiltrated, the entire contents of the crucible can be allowed to cool in place, and the composite part recovered from the mold.

  16. Flattening and Cooling of Millimeter- and Micrometer-Sized Alumina Drops

    NASA Astrophysics Data System (ADS)

    Goutier, S.; Vardelle, M.; Labbe, J. C.; Fauchais, P.

    2011-01-01

    An experimental setup was developed to produce fully melted, millimeter-sized, ceramic or metallic drops with impact velocities up to 10 m/s. Such impact velocities allow achievement of impact Weber numbers, close to those of the plasma spray process ( We = 2300) with droplets in the tens of micrometer size range. A fast camera (4000 image/s) combined with a fast pyrometer (4000 Hz), allowed the flattening of the drop to be followed. To study the flattening of micrometer-sized droplets, a direct-current (dc) plasma torch was used to melt alumina particles (around 45 μm in diameter). The experimental setup was composed of a fast (50 ns) two-color pyrometer and two fast (at best an exposure time of 2 μs) charge-coupled device cameras (one orthogonal and other tangential to the substrate). The flattening behaviors of millimeter- and micrometer-sized particles were compared. First, impacts of alumina drops (millimeter-sized) with velocities up to 10 m/s were studied. Results were then compared with micrometer-sized alumina particles (about 45 μm in diameter) sprayed with the dc plasma torch. A correlation was found between both flattening scales, and, in spite of the lower impact velocity at the millimeter scale, droplet ejections were also found as obtained at the micrometer scale. This work shows that for a sound comparison of phenomena at the two different scales it is mandatory to have Weber numbers as close as possible in both cases.

  17. Portrait of Candida albicans Adherence Regulators

    PubMed Central

    Finkel, Jonathan S.; Xu, Wenjie; Huang, David; Hill, Elizabeth M.; Desai, Jigar V.; Woolford, Carol A.; Nett, Jeniel E.; Taff, Heather; Norice, Carmelle T.; Andes, David R.; Lanni, Frederick; Mitchell, Aaron P.

    2012-01-01

    Cell-substrate adherence is a fundamental property of microorganisms that enables them to exist in biofilms. Our study focuses on adherence of the fungal pathogen Candida albicans to one substrate, silicone, that is relevant to device-associated infection. We conducted a mutant screen with a quantitative flow-cell assay to identify thirty transcription factors that are required for adherence. We then combined nanoString gene expression profiling with functional analysis to elucidate relationships among these transcription factors, with two major goals: to extend our understanding of transcription factors previously known to govern adherence or biofilm formation, and to gain insight into the many transcription factors we identified that were relatively uncharacterized, particularly in the context of adherence or cell surface biogenesis. With regard to the first goal, we have discovered a role for biofilm regulator Bcr1 in adherence, and found that biofilm regulator Ace2 is a major functional target of chromatin remodeling factor Snf5. In addition, Bcr1 and Ace2 share several target genes, pointing to a new connection between them. With regard to the second goal, our findings reveal existence of a large regulatory network that connects eleven adherence regulators, the zinc-response regulator Zap1, and approximately one quarter of the predicted cell surface protein genes in this organism. This limited yet sensitive glimpse of mutant gene expression changes had thus defined one of the broadest cell surface regulatory networks in C. albicans. PMID:22359502

  18. Effects of ball milling and sintering on alumina and alumina-boron compounds

    NASA Astrophysics Data System (ADS)

    Cross, Thomas

    Alumina has a wide variety of applications, but the processing of alumina based materials can be costly. Mechanically milling alumina has been shown to enhance the sintering properties while decreasing the sintering temperature. Additions of boron have also proven to increase sintering properties of alumina. These two processes, mechanical milling and boron additions, will be combined to test the sintering properties and determine if they are improved upon even further compared to the individual processes. Multiple samples of pure alumina, 0.2 weight percent boron, and 1.0 weight percent boron are batched and processed in a ball mill for different time intervals. These samples are then characterized to observe the structure and properties of the samples after milling but before sintering. Pellets are dry pressed from the milled powders, sintered at 1200°C for one to 10 hours, and characterized to determine the impact of processing. X-ray diffractometry (XRD) was used on each sample to determine crystallite size and lattice parameters at different stages throughout the experiment. XRD was also used to identify any samples with an aluminum borate phase. Scanning electron microscopy (SEM) was used to observe the powder and pellet morphology and to measure bulk chemical composition. Samples were sputter coated with an Au-Pd coating observed in the SEM to characterize the topography as a function of variables such as milling time, boron composition, and sintering time. Additionally, porosity and change in diameter were measured to track the sintering process. Milling sample for longer periods of time would be unnecessary due to the crystallite size leveling off between 10 and 12 hours of milling time. Samples of alumina with 0.2 weight percent boron prove to have very little effect on the sintering properties. At 1.0 weight percent boron, there are changes in diffraction patterns and topography after being sintered for one hour. The porosities of all of the sintered

  19. Alumina-Forming MAX Phases in Turbine Material Systems

    NASA Technical Reports Server (NTRS)

    Smialek, James L.; Harder, Bryan J.; Garg, Arnita; Nesbitt, James A.

    2015-01-01

    Coatings for high temperature turbine components are based on low conductivity YSZ thermal barriers and protective NiAl, NiCoCrAlY bond coats. Good oxidation hot corrosion resistance, intermediate CTE, and strain tolerance of Ti2AlC and Cr2AlC MAX phases are thus of special interest. Their alumina scale growth follows a cubic law in accord with FeCrAlY alloys, with oxygen grain boundary diffusivity: Dgb 1.8 x 10-10 exp(-375 kJmole) m3s. Protective cubic kinetics are also found in high pressure burner rig (6 atm., 25 ms) and TGA tests of MAXthal 211Ti2AlC. The initial portion (0.1 hr) is dominated by fast TiO2 growth (with little evidence of scale volatility in high pressure water vapor, as found for SiO2 scales). Bulk Ti2AlC and Cr2AlC substrates show promise as potential bond coats for YSZ TBCs in 1000-1200 C furnace life (500 h) tests. Cr2AlC is proving to be very resistant to 700-900 C Na2SO4 hot corrosion and is of interest for disk alloys. Preliminary diffusion bonded Cr2AlC-superalloy hybrid couples have survived 1000 hr interrupted furnace tests at 800C with no indication of cracking or debonding. Diffusion zones of -NiAl+Cr7C3 were produced in these above 1000 C, but did not grow to any great extent after 1000 hr at 800 C. Processing as coatings presents challenges, however the basic properties of MAX phases provide novel opportunities for high temperature turbine components.

  20. Patient Medication Adherence and Physician Prescribing among Congestive Heart Failure Patients of Yemen.

    PubMed

    Alakhali, K M; Daniel, P S; Noohu, A M; Sirajudeen, S A

    2013-09-01

    Congestive heart failure has been associated with high morbidity and mortality requiring hospitalisation and is further complicated by noncompliance and under prescriptions. We aim to determine medication adherence and percentage deviation among Asians population in general and Yemenis in particular. A cross-sectional, prospective observational study with purposive sampling was conducted at two cardiac outpatient centers in 70 congestive heart failure patients for a period of 3 months. An Arabic translated Morisky 4 item scale assessed the adherence of patients. Deviation in prescribing was determined by chart review. All 70 patients had mean age of 56.6±16 years. Morisky 4 item scale predicted low adherence (n=33; 47.1%) and overall nonadherencerate (n=38; 54.2%) was slightly higher than adherence. Percentage nonadherence versus adherence was high with diuretics (53 vs. 46%) and, digoxin (40 vs. 29%). The adherence percentage of angiotensin receptor blockers (9%) and beta blockers (8%) was low. Diuretics were the most prescribed drugs (n=69; 99%), followed by angiotensin converting enzyme inhibitors (n=51; 73%), cardiac glycoside (n=48; 69%), few patients were on angiotensin receptor blockers (n=8; 11%) and (n=9; 13%) beta blockers. The maximum prescribing rate deviation was seen with angiotensin receptor blockers (-89%) and beta blockers (-87%) followed by nitrates (-77%). Digoxin (-31%) and angiotensin converting enzymes (-27%) deviated comparatively less. Prescribing as well as utilisation rates generally were low resulting in nonachievement of therapeutic goals which could be resolved using multimodel approach. PMID:24403656

  1. Anodisation with dynamic current control for tailored alumina coatings

    NASA Astrophysics Data System (ADS)

    Sieber, M.; Althöfer, I.; Höhlich, D.; Scharf, I.; Böttger, D.; Böttger, S.; Böttger, E.; Lampke, T.

    2016-03-01

    The anodic oxidation process is commonly used to refine the surface of aluminium and its alloys. Compared to the substrate, the alumina layers produced by anodising exhibit an increased hardness and chemical resistance. Thus, the corrosion and wear resistance are generally improved. The coatings are also electrically isolating and may serve decorative purposes. Applying a time-variant, dynamic electrical process control by pulse-current or current-steps is a promising approach to improve the coating properties, which is partially deployed in an industrial scale. In the present work, the influence of dynamic electrical process control on the coating properties is examined by means of a design of experiments (DOE). The effects of various electrolyte compositions and temperatures as well as processing time are considered with regard to coating thickness, hardness, wear resistance and the electrical energy consumption during the formation of the coatings. Information about the statistical significance of the effects of the parameters on the considered properties is obtained by an analysis of variance (ANOVA).

  2. Fabrication of whisker-toughened alumina tubes. Final report

    SciTech Connect

    Loutfy, R.O.

    1993-09-01

    A process has been developed to fabricate whisker toughened alumina composites by slip casting dense colloidal suspensions of Al{sub 2}O{sub 3}-15% SiC{sub w}. Optimum processing parameters for slip casting we developed with slip viscosity of 60--70 centipoise and solids content 78--79 wt %. Slip-cast parts with green densities 65 to 68% theoretical were achieved. Composite parts were pressureless sintered to 96--97% theoretical density with <1% open porosity. The composites exhibited strengths of 500 MPa, toughness of 6.5 MPa m{sup 1/2}, and hardness of 17.26 GPa (1765 kg/mm{sup 2}). High temperature strength retention was maintained up to 1200C. Good thermal shock resistance with {Delta}T{sub cr} = 500C was also achieved. The process technology was transferred into pilot scale for producing prototype heat exchanger tubing up to 4 inches in diameter at the facilities of Vesuvius/McDanel.

  3. Ultrafast excited state deactivation of doped porous anodic alumina membranes

    NASA Astrophysics Data System (ADS)

    Makhal, Abhinandan; Sarkar, Soumik; Pal, Samir Kumar; Yan, Hongdan; Wulferding, Dirk; Cetin, Fatih; Lemmens, Peter

    2012-08-01

    Free-standing, bi-directionally permeable and ultra-thin anodic aluminum oxide (AAO) membranes establish attractive templates (host) for the synthesis of nano-dots and rods of various materials (guest). This is due to their chemical and structural integrity and high periodicity on length scales of 5-150 nm which are often used to host photoactive nano-materials for various device applications including dye-sensitized solar cells. In the present study, AAO membranes are synthesized by using electrochemical methods and a detailed structural characterization using FEG-SEM, XRD and TGA confirms the porosity and purity of the material. Defect-mediated photoluminescence quenching of the porous AAO membrane in the presence of an electron accepting guest organic molecule (benzoquinone) is studied by means of steady-state and picosecond/femtosecond-resolved luminescence measurements. Using time-resolved luminescence transients, we have also revealed light harvesting of complexes of porous alumina impregnated with inorganic quantum dots (Maple Red) or gold nanowires. Both the Förster resonance energy transfer and the nano-surface energy transfer techniques are employed to examine the observed quenching behavior as a function of the characteristic donor-acceptor distances. The experimental results will find their relevance in light harvesting devices based on AAOs combined with other materials involving a decisive energy/charge transfer dynamics.

  4. Therapist Competence and Treatment Adherence for a Brief Intervention addressing Alcohol and Violence among Adolescents

    PubMed Central

    Resko, Stella M.; Walton, Maureen A.; Chermack, Stephen T.; Blow, Frederic C.; Cunningham, Rebecca M.

    2011-01-01

    This study examines therapist competency and treatment adherence for a brief intervention addressing alcohol misuse and violent behaviors among adolescents aged 14–18. Three observational measures of fidelity were used by independent raters to evaluate 60 therapist-delivered sessions (m=32.5 minutes). Individual items from the Content Adherence scale, the Global Rating of Competence (GROMIT) and Self Exploration and Change Talk (SECT) demonstrated fair to excellent inter-rater reliability (intraclass correlations ranged from .40 to 1.0). Principal components analysis (PCA) was utilized to identify the underlying factor structure of the Content Adherence and GROMIT. Parallel analysis suggested the extraction of three components for the Content Adherence reflecting the three distinct goals for each segment of the intervention. Two components were identified for the GROMIT representing the general spirit of motivational interviewing and empowerment. Findings provide support for the fidelity instruments adapted for this study and offer direction for future training and clinical supervision. PMID:22119182

  5. Antiretroviral Treatment Adherence Rate and Associated Factors among People Living with HIV in Dubti Hospital, Afar Regional State, East Ethiopia

    PubMed Central

    Negus, Rahma

    2015-01-01

    Introduction. Antiretroviral Therapy has transformed HIV infection into a chronic manageable disease; it requires near perfect adherence rates (as high as 95%). In this study, we assessed antiretroviral treatment adherence rate and associated factors among people living with HIV in Dubti Hospital. Methods. A retrospective cross-sectional study design was conducted within February 1–30, 2014. All HIV-infected patients above the age of 18 years who took first line Antiretroviral Therapy were eligible for inclusion of the study. Adherence Scale was used for labeling patients as adherent or nonadherent. All HIV-infected patients record data were collected from the medical records, entered, and analyzed using Epi Info 7 and SPSS Version 20. Multivariable analysis was used to identify the relative effect of explanatory variables on low adherence rate. Results. A total of 370 patients aged 18 years and above, who started ART, were included in this study. The self-reported adherence rate of the patient on ART was 81.1%. Independent predictors of adherence were treatment duration. Conclusion. Adherence rate was associated with time to ART. That is, the longer they were on ART, the lesser they adhered.

  6. Infection Control Practice in the Operating Room: Staff Adherence to Existing Policies in a Developing Country

    PubMed Central

    Cawich, Shamir O; Tennant, Ingrid A; McGaw, Clarence D; Harding, Hyacinth; Walters, Christine A; Crandon, Ivor W

    2013-01-01

    Context: Infection control interventions are important for containing surgery-related infections. For this reason, the modern operating room (OR) should have well-developed infection control policies. The efficacy of these policies depends on how well the OR staff adhere to them. There is a lack of available data documenting adherence to infection control policies. Objective: To evaluate OR staff adherence to existing infection control policies in Jamaica. Methods: We administered a questionnaire to all OR staff to assess their training, knowledge of local infection control protocols, and practice with regard to 8 randomly selected guidelines. Adherence to each guideline was rated with fixed-choice items on a 4-point Likert scale. The sum of points determined the adherence score. Two respondent groups were defined: adherent (score > 26) and nonadherent (score ≤ 26). We evaluated the relationship between respondent group and age, sex, occupational rank, and time since completion of basic medical training. We used χ2 and Fisher exact tests to assess associations and t tests to compare means between variables of interest. Results: The sample comprised 132 participants (90 physicians and 42 nurses) with a mean age of 36 (standard deviation ± 9.5) years. Overall, 40.1% were adherent to existing protocols. There was no significant association between the distribution of adherence scores and sex (p = 0.319), time since completion of basic training (p = 0.595), occupational rank (p = 0.461), or age (p = 0.949). Overall, 19% felt their knowledge of infection control practices was inadequate. Those with working knowledge of infection control practices attained it mostly through informal communication (80.4%) and self-directed research (62.6%). Conclusion: New approaches to the problem of nonadherence to infection control guidelines are needed in the Caribbean. Several unique cultural, financial, and environmental factors influence adherence in this region, in contrast to

  7. Potential Savings From Increasing Adherence to Inhaled Corticosteroid Therapy in Medicaid-Enrolled Children

    PubMed Central

    Rust, George; Zhang, Shun; McRoy, Luceta; Pisu, Maria

    2016-01-01

    Background Many asthma-related exacerbations could be prevented by consistent use of daily inhaled corticosteroid therapy (ICS-Rx). Objectives We sought to measure the potential cost savings that could accrue from increasing ICS-Rx adherence in children. Study Design We measured observed costs for a cohort of 43,156 Medicaid-enrolled children in 14 southern states whose initial ICS-Rx was prescribed in 2007. Methods Adherence rates and associated costs were calculated from Medicaid claims. Children were categorized as high or low adherence based on the ratio of ICS-Rx claims filled to total asthma drug claims. Branching tree simulation was used to project the potential cost savings achieved by increasing the proportion of children with ICS-Rx to total asthma Rx ratios greater than 0.5 to 20%, 40%, 60%, 80%, and 100%. Results Increasing the proportion of children who maintain higher adherence after initial ICS-Rx to 40% would generate savings of $95 per child per year. An intervention costing $10 per member per month that resulted in even half of the children maintaining high adherence would generate a 98% return on investment for managed care plans or state Medicaid programs. Net costs decreased incrementally at each level of increase in ICS-Rx adherence. The projected Medicaid cost savings for these 14 states in 2007 ranged from $8.2 million if 40% of the children achieved high adherence, to $57.5 million if 80% achieved high adherence. Conclusions If effective large-scale interventions can be found, there are substantial cost savings to be gained from even modest increases in real-world adherence to ICS-Rx among Medicaid-enrolled children with asthma. PMID:25880622

  8. A method for decomposition of hexachlorobenzene by gamma-alumina.

    PubMed

    Zhang, Lifei; Zheng, Minghui; Liu, Wenbin; Zhang, Bing; Su, Guijin

    2008-02-11

    A method of decomposing hexachlorobenzene (HCB) by gamma-alumina was investigated at low temperature of 300 degrees C. It was found that HCB was rather quickly decomposed under such a condition. Decomposition efficiency (DE) increases with increasing the surface area of gamma-alumina. Pretreated gamma-alumina has a better performance for the decomposition reaction. A high decomposition efficiency within the short reactive time of 60 min was achieved to be 94.2%, which was obtained by preheating gamma-alumina with the surface area of 220 m(2)g(-1) at 450 degrees C for 2 h. High surface area and appropriate pretreatment temperature probably provide more reactive sites such as the isolated OH groups and Al(3+) sites surrounded by O(2-) sites. These sites may induce the decomposition of HCB via a main ring-cracking process. The present study, hopefully, holds the promise for the eliminating of HCB contained hazardous materials in industrial application. PMID:18037236

  9. Alumina microstructural sample preparation using a borate glaze

    SciTech Connect

    Scott, C.; Hill, S.; Hosmer, K.

    1986-03-01

    A method was developed for preparing alumina surfaces for microstructural analysis. Samples were polished using a sodium borate glaze, which produced a smooth surface with the grain boundaries accented.

  10. Removing Fluoride Ions with Continously Fed Activated Alumina.

    ERIC Educational Resources Information Center

    Wu, Yeun C.; Itemaking, Isara Cholapranee

    1979-01-01

    Discussed is the mathematical basis for determining fluoride removal during water treatment with activated alumina. The study indicates that decreasing particle size decreases the pore diffusion effect and increases fluoride removal. (AS)

  11. Aluminum microstructures on anodic alumina for aluminum wiring boards.

    PubMed

    Jha, Himendra; Kikuchi, Tatsuya; Sakairi, Masatoshi; Takahashi, Hideaki

    2010-03-01

    The paper demonstrates simple methods for the fabrication of aluminum microstructures on the anodic oxide film of aluminum. The aluminum sheets were first engraved (patterned) either by laser beam or by embossing to form deep grooves on the surface. One side of the sheet was then anodized, blocking the other side by using polymer mask to form the anodic alumina. Because of the lower thickness at the bottom part of the grooves, the part was completely anodized before the complete oxidation of the other parts. Such selectively complete anodizing resulted in the patterns of metallic aluminum on anodic alumina. Using the technique, we fabricated microstructures such as line patterns and a simple wiring circuit-board-like structure on the anodic alumina. The aluminum microstructures fabricated by the techniques were embedded in anodic alumina/aluminum sheet, and this technique is promising for applications in electronic packaging and devices. PMID:20356280

  12. Fabrication method produces high-grade alumina crucibles

    NASA Technical Reports Server (NTRS)

    Palmour, H.

    1965-01-01

    Alumina-binder mixture, which has been dry pressed in a die using a mating punch, forms crucibles of various configurations and after firing results in a ceramic structure for use in diffusion experiments.

  13. Thermophysical Properties of Sodium (Beta)-Alumina Polycrystalline Ceramic

    NASA Technical Reports Server (NTRS)

    Ryan, M. A.; Williams, R. M.; Allevato, C. E.; Vining, C. B.; Lowe-Ma, C. K.; Robie, S. B.

    1994-01-01

    Teh thermal diffusivity, heat capacity and thermal conductivity of solid samples of new, Li-stabilized, sodium (Beta)-alumina polycrystalline ceramic have been determined in the temperature range 500-1200 K.

  14. Use of surfactants in alumina precipitation in the bayer process

    SciTech Connect

    Owen, D.O.; Davis, D.C.

    1988-04-12

    In the method for producing alumina trihydrate crystals by crystallization of alumina trihydrate from a hot, caustic pregnant Bayer process liquor, to obtain a reduced percent of small size crystals -325 mesh fraction thereby to increase the yield of crystals coarser than -325 mesh subsequently to be processed to yield aluminum, the improvement is described comprising the addition to the pregnant liquor, after red mud separation and immediately prior to crystallization of alumina trihydrate, of two mutually soluble components (A) and (B) in an amount effective to increase the yield of the coarser crystals, component (A) being a surfactant which will disperse component (B) in the pregnant liquor and component (B) being an oil in which the surfactant is dissolved and having a boiling point above the temperature prevailing alumina hydrate crystallization.

  15. Potassium Beta-Alumina/Molybdenum/Potassium Electrochemical Cells

    NASA Technical Reports Server (NTRS)

    Williams, R.; Kisor, A.; Ryan, M.; Nakamura, B.; Kikert, S.; O'Connor, D.

    1994-01-01

    potassium alkali metal thermal-to-electric converter (K-AMTEC) cells utilizing potassium beta alumina solid electrolyte (K-BASE) are predicted to have improved properties for thermal to electric conversion at somewhat lower temperatures than sodium AMTEC's.

  16. Dietary adherence and acceptability of five different diets, including vegan and vegetarian diets, for weight loss: The New DIETs study.

    PubMed

    Moore, Wendy J; McGrievy, Michael E; Turner-McGrievy, Gabrielle M

    2015-12-01

    The goal of the present study was to examine dietary adherence and acceptability among participants from the New DIETs study who were randomized to one of four plant-based diets (vegan, vegetarian, pesco-vegetarian, semi-vegetarian) or an omnivore diet. Primary outcomes at two- and six months included dietary adherence (24-hour dietary recalls), weight loss and changes in animal product intake (mg cholesterol) by adherence status, Three-Factor Eating Questionnaire (TFEQ), Power of Food Scale (PFS), dietary acceptability (Food Acceptability Questionnaire), and impact of diet preference on adherence. No differences were found in dietary adherence or changes in FAQ, TFEQ, or PFS among the groups. At six months, non-adherent vegan and vegetarian participants (n=16) had a significantly greater decrease in cholesterol intake (-190.2 ± 199.2 mg) than non-adherent pesco-vegetarian/semi-vegetarian (n=15, -2.3 ± 200.3 mg, P=0.02) or omnivore participants (n=7, 17.0 ± 36.0, P=0.04). Non-adherent vegan/vegetarian participants lost significantly more weight at six months (-6.0 ± 6.7%) than non-adherent omnivore participants (-0.4 ± 0.6%, P=0.04). Dietary preference had no impact on adherence at six months. Due to equal rates of adherence and acceptability among the diet groups, instructing participants to follow vegan or vegetarian diets may have a greater impact on weight loss and animal product intake than providing instruction in more moderate approaches even among non-adherent participants. PMID:26164391

  17. Maintaining Adherence Programme: evaluation of an innovative service model

    PubMed Central

    Lewis, Llewellyn; O'Keeffe, Christine; Smyth, Ian; Mallalieu, Judi; Baldock, Laura; Oliver, Sam

    2016-01-01

    Aims and method The Maintaining Adherence Programme (MAP) is a new model of care for patients with schizophrenia, schizoaffective disorder and bipolar affective disorder which aims to encourage adherence and prevent relapse. This evaluation, conducted by retrospective and prospective data collection (including patient questionnaires and staff interviews), aimed to describe MAP's impact on healthcare resource use, clinical measures and patient and staff satisfaction, following its implementation in a university National Health Service (NHS) foundation trust in England. We included 143 consenting patients who entered MAP before 31 March 2012. Results In-patient bed days and non-MAP NHS costs reduced significantly in the 18 months post-MAP entry. At 15–18 months post-MAP, Medication Adherence Rating Scale scores had improved significantly from baseline and there was a shift towards less severe clinician-rated disease categories. Based on patient surveys, 96% would recommend MAP to friends, and staff were also overwhelmingly positive about the service. Clinical implications MAP was associated with reduced cost of treatment, improvements in clinical outcomes and very high patient and staff satisfaction. PMID:26958352

  18. Treatment adherence to disease-modifying antirheumatic drugs in Chinese patients with rheumatoid arthritis

    PubMed Central

    Xia, Yunfei; Yin, Rulan; Fu, Ting; Zhang, Lijuan; Zhang, Qiuxiang; Guo, Genkai; Li, Liren; Gu, Zhifeng

    2016-01-01

    Objective Nonadherence in rheumatoid arthritis (RA) patients using disease-modifying antirheumatic drugs (DMARDs) may lead to joint damage and function loss. The aim of this cross-sectional study was to explore Chinese RA patients’ adherence rates and investigate potential risk factors for nonadherence. Methods A total of 122 RA patients were recruited from the Affiliated Hospital of Nantong University from January 2014 to April 2015. Patients were asked to complete a set of standardized self-report questionnaires (Compliance Questionnaire on Rheumatology, Health Assessment Questionnaire, Short Form-36 questionnaire, 28-joint Disease Activity Score, Hospital Anxiety and Depression Scale, and Visual Analog Scale). Independent samples t-tests, chi-square analyses, and logistic regression modeling were used to analyze these data. Results Based on Compliance Questionnaire on Rheumatology, 38% of the patients adhered to DMARDs. Adherence was associated with education, income, depression, and the total number of DMARDs. Other demographic and clinical characteristics were not associated with adherence. Logistic regression models identified income, depression, and the total number of DMARDs as predictors of medication nonadherence. Conclusion In this study, 62% of patients with RA were not adherent to their DMARD prescription. Education, income, depression, and the total number of DMARDs were associated with medication adherence, and income, depression, and the total number of DMARDs were independent predictors of medication adherence in patients with RA. These findings could help medical personnel develop helpful interventions to improve adherence in RA patients by paying more attention to the patients with these accompanying risk factors and, finally, improve RA patients’ quality of life. PMID:27217726

  19. Bayesian population modeling of drug dosing adherence.

    PubMed

    Fellows, Kelly; Stoneking, Colin J; Ramanathan, Murali

    2015-10-01

    Adherence is a frequent contributing factor to variations in drug concentrations and efficacy. The purpose of this work was to develop an integrated population model to describe variation in adherence, dose-timing deviations, overdosing and persistence to dosing regimens. The hybrid Markov chain-von Mises method for modeling adherence in individual subjects was extended to the population setting using a Bayesian approach. Four integrated population models for overall adherence, the two-state Markov chain transition parameters, dose-timing deviations, overdosing and persistence were formulated and critically compared. The Markov chain-Monte Carlo algorithm was used for identifying distribution parameters and for simulations. The model was challenged with medication event monitoring system data for 207 hypertension patients. The four Bayesian models demonstrated good mixing and convergence characteristics. The distributions of adherence, dose-timing deviations, overdosing and persistence were markedly non-normal and diverse. The models varied in complexity and the method used to incorporate inter-dependence with the preceding dose in the two-state Markov chain. The model that incorporated a cooperativity term for inter-dependence and a hyperbolic parameterization of the transition matrix probabilities was identified as the preferred model over the alternatives. The simulated probability densities from the model satisfactorily fit the observed probability distributions of adherence, dose-timing deviations, overdosing and persistence parameters in the sample patients. The model also adequately described the median and observed quartiles for these parameters. The Bayesian model for adherence provides a parsimonious, yet integrated, description of adherence in populations. It may find potential applications in clinical trial simulations and pharmacokinetic-pharmacodynamic modeling. PMID:26319548

  20. Carbon dioxide pressure swing adsorption process using modified alumina adsorbents

    DOEpatents

    Gaffney, Thomas Richard; Golden, Timothy Christopher; Mayorga, Steven Gerard; Brzozowski, Jeffrey Richard; Taylor, Fred William

    1999-01-01

    A pressure swing adsorption process for absorbing CO.sub.2 from a gaseous mixture containing CO.sub.2 comprising introducing the gaseous mixture at a first pressure into a reactor containing a modified alumina adsorbent maintained at a temperature ranging from 100.degree. C. and 500.degree. C. to adsorb CO.sub.2 to provide a CO.sub.2 laden alumina adsorbent and a CO.sub.2 depleted gaseous mixture and contacting the CO.sub.2 laden adsorbent with a weakly adsorbing purge fluid at a second pressure which is lower than the first pressure to desorb CO.sub.2 from the CO.sub.2 laden alumina adsorbent. The modified alumina adsorbent which is formed by depositing a solution having a pH of 3.0 or more onto alumina and heating the alumina to a temperature ranging from 100.degree. C. and 600.degree. C., is not degraded by high concentrations of water under process operating conditions.

  1. Carbon dioxide pressure swing adsorption process using modified alumina adsorbents

    DOEpatents

    Gaffney, T.R.; Golden, T.C.; Mayorga, S.G.; Brzozowski, J.R.; Taylor, F.W.

    1999-06-29

    A pressure swing adsorption process for absorbing CO[sub 2] from a gaseous mixture containing CO[sub 2] comprises introducing the gaseous mixture at a first pressure into a reactor containing a modified alumina adsorbent maintained at a temperature ranging from 100 C and 500 C to adsorb CO[sub 2] to provide a CO[sub 2] laden alumina adsorbent and a CO[sub 2] depleted gaseous mixture and contacting the CO[sub 2] laden adsorbent with a weakly adsorbing purge fluid at a second pressure which is lower than the first pressure to desorb CO[sub 2] from the CO[sub 2] laden alumina adsorbent. The modified alumina adsorbent which is formed by depositing a solution having a pH of 3.0 or more onto alumina and heating the alumina to a temperature ranging from 100 C and 600 C, is not degraded by high concentrations of water under process operating conditions. 1 fig.

  2. Superhydrophobic surfaces fabricated by surface modification of alumina particles

    NASA Astrophysics Data System (ADS)

    Richard, Edna; Aruna, S. T.; Basu, Bharathibai J.

    2012-10-01

    The fabrication of superhydrophobic surfaces has attracted intense interest because of their widespread potential applications in various industrial fields. Recently, some attempts have been carried out to prepare superhydrophobic surfaces using metal oxide nanoparticles. In the present work, superhydrophobic surfaces were fabricated with low surface energy material on alumina particles with different sizes. It was found that particle size of alumina is an important factor in achieving stable superhydrophobic surface. It was possible to obtain alumina surface with water contact angle (WCA) of 156° and a sliding angle of <2°. Superhydrophobicity of the modified alumina is attributed to the combined effect of the micro-nanostructure and low surface energy of fatty acid on the surface. The surface morphology of the alumina powder and coatings was determined by FESEM. The stability of the coatings was assessed by conducting water immersion test. Effect of heat treatment on WCA of the coating was also studied. The transition of alumina from hydrophilic to superhydrophobic state was explained using Wenzel and Cassie models. The method is shown to have potential application for creating superhydrophobic surface on cotton fabrics.

  3. Wetting and strength issues at Al/alpha-alumina interfaces

    SciTech Connect

    Saiz, Eduardo; Tomsia, Antoni P.; Suganuma, Katsuaki

    2003-04-15

    The wetting behavior and strength at aluminum/alumina interfaces has been an active subject of research. Al/alumina applications include ceramic-metal composites and several applications for electronic industries. In this paper the interface strength and microstructure of Al/alpha-alumina was investigated. We discovered that in a solid-state joining, the strength of the joint increases with increasing joining temperature. In a liquid-state joining, the strength of the joint gradually decreases due to the formation of unbonded areas. The strength, sigma sub b, is expressed by the following equation as a function of unbonded area, A: sigma sub b = 2.22 A + 143 (70 percent {le} A {le} 100 percent). The highest strength reached 400 MPa when the interface was formed at around the melting temperature of aluminum. An aluminum layer close to the interface became a single crystal when it was bonded to a sapphire. The following crystallographic orientation relationship is established: (1{bar 1}1){sub Al}//(001){sub {alpha}}-Al{sub 2} O{sub 3}, (110){sub Al}//<100>{sub {alpha}}-Al{sub 2}O{sub 3}. Amorphous alumina islands were formed at the interface. In the amorphous alumina, gamma-alumina nanocrystals grew from the sapphire, with the same orientation relationship to sapphire as above.

  4. Patient Education and Adherence to Aerosol Therapy.

    PubMed

    Ari, Arzu

    2015-06-01

    Nonadherence to prescribed medications results in disease instability and poor clinical control, with increases in hospital admissions, emergency room visits, school/work absenteeism, morbidity, and mortality. Poor patient adherence to therapy can be due to lack of cognition, competence, or contrivance. Patients who have not been trained or fail to understand use of drug and device combinations (cognition) often do not have the ability to use an aerosol device correctly (competence). Many patients have the competence to use the device correctly and know why they should use the device in the way they were taught; however, they still contrive to use it in an ineffective and suboptimal manner that reduces its efficiency and effectiveness. Ensuring effective aerosol therapy and optimizing its role in disease management involve not only delivery of aerosolized medications to the lungs, but also understanding why, when, and how to use the medications, competence to use the device, motivation to adhere to therapy, and not contriving to use the device in a way that will prevent effective drug delivery. This paper explains some of the problems with patient education and adherence to aerosol therapy and suggests strategies to evaluate, monitor, and improve patient adherence effectively in primary care. Factors affecting patient adherence to prescribed medications, effective educational interventions, and strategies to promote patient adherence to aerosol therapy are also discussed. PMID:26070585

  5. Effects of Etching Time and NaOH Concentration on the Production of Alumina Nanowires Using Porous Anodic Alumina Template

    NASA Astrophysics Data System (ADS)

    Sadeghpour-Motlagh, M.; Mokhtari-Zonouzi, K.; Aghajani, H.; Kakroudi, M. Ghassemi

    2014-06-01

    In this work, two-step anodizing of commercial aluminum foil in acid oxalic solution was applied for producing alumina film. Then the anodic alumina film was etched in sodium hydroxide (NaOH) solution resulting dense and aligned alumina nanowires. This procedure leads to splitting of alumina nanotubes. Subsequently nanowires are produced. The effects of NaOH solution concentration (0.2-1 mol/L) and etching time (60-300 s) at constant temperature on characteristic of nanotubes and produced nanowires were investigated using scanning electron microscopy. The results show that an increase in NaOH solution concentration increases the rate of nanowires production and in turn the manipulation process will be more specific.

  6. Structure, stoichiometry and stability in magnetoplumbite and [beta]-alumina type ceramics

    SciTech Connect

    Cormack, A.N.; Park, J.G.

    1992-12-01

    Work has continued on the computer simulation of atomic scale defect complexes in polyaluminates with the magnetoplumbate and [beta]-alumina structures. More stringent criteria have been developed for determining the viability of interatomic potential models for these complex structured materials, details of the cation coordination having been found to be important. It appears that the energetics of point defect complex formation is the reason why Ba hexa-aluminate does not adopt the magnetoplumbate structure, in contrast to Sr hexa-aluminate, which does.

  7. Structure, stoichiometry and stability in magnetoplumbite and {beta}-alumina type ceramics. Technical progress report

    SciTech Connect

    Cormack, A.N.; Park, J.G.

    1992-12-01

    Work has continued on the computer simulation of atomic scale defect complexes in polyaluminates with the magnetoplumbate and {beta}-alumina structures. More stringent criteria have been developed for determining the viability of interatomic potential models for these complex structured materials, details of the cation coordination having been found to be important. It appears that the energetics of point defect complex formation is the reason why Ba hexa-aluminate does not adopt the magnetoplumbate structure, in contrast to Sr hexa-aluminate, which does.

  8. Adherence to highly active antiretroviral therapy impact on clinical and economic outcomes for Medicaid enrollees with HIV and hepatitis C co-infection

    PubMed Central

    Zhang, Shun; Rust, George; Cardarelli, Kathryn; Felizzola, Jesus; Fransua, Mesfin; Stringer, Harold G.

    2016-01-01

    We examined the impact of antiretroviral treatment adherence among Hepatitis C co-infected HIV patients on survival and clinical outcomes. We analyzed Medicaid claims data from fourteen southern states from 2005-2007, comparing survival and clinical outcomes and cost of treatment for HIV and hepatitis-C co-infected patients (N=4,115) at different levels of adherence to antiretroviral therapy.More than one in five patients (20.5%) showed less than 50% adherence to antiretroviral treatment, but there were no racial-ethnic or gender disparities. Significant survival benefit was demonstrated at each incremental level of adherence to antiretroviral therapy (one-year mortality ranging from 3.5% in the highest adherence group to 26.0% in the lowest). Low adherence patients also had higher rates of hospitalization and emergency department visits. Relative to patients with high (>95%) ART-adherence, those with less than 25% treatment adherence had four-fold greater risk of death (adjusted odds ratio 4.22 [95% CI, 3.03,5.87]). Non-drug Medicaid expenditures were lower for high adherence patients, but cost of medications drove total Medicaid expenditures higher for high-adherence patients. Cost per quality-adjusted life year (QALY) saved (relative to the <25% low-adherence group) ranged from $21,874 for increasing adherence to 25-50% to $37,229 for increasing adherence to 75-95%. Adherence to antiretroviral therapy for patients with HIV and hepatitis C co-infection is associated with lower adverse clinical outcomes at a Medicaid cost per QALY commensurate with other well-accepted treatment and prevention strategies. Further research is needed to identify interventions which can best achieve optimal ART adherence at a population scale. PMID:25814041

  9. Predicting Malawian Women’s Intention to Adhere to Antiretroviral Therapy

    PubMed Central

    McKinney, Ogbochi; Modeste, Naomi N.; Lee, Jerry W.; Gleason, Peter C.

    2015-01-01

    Background With the increase in scaling up of antiretroviral therapy (ART), knowledge of the need for adherence to ART is pivotal for successful treatment outcomes. Design and Methods A cross-sectional study was carried out between October and December 2013. We administered theory of planned behaviour (TPB) and adherence questionnaires to 358 women aged 18-49 years, from a rural and urban ART-clinics in southern Malawi. Hierarchical linear regression models were used to predict intentions to adhere to ART. Results Regression models show that attitude (β=0.47), subjective norm (β=0.31) and perceived behavioural control (β=0.12) explain 55% of the variance in intentions to adhere to ART. The relationship between both food insecurity and perceived side effects with intentions to adhere to ART is mediated by attitude, subjective norm, and perceived behavioural control. Household (r=0.20) and individual (r=0.21) food insecurity were positively and significantly correlated with perceived behavioural control. Household food insecurity had a negative correlation with perceived side effects (r=-0.11). Perceived side effects were positively correlated with attitude (r=0.25). There was no statistically significant relationship between intentions to adhere to ART in the future and one month self-report of past month adherence. These interactions suggest that attitude predicted adherence only when food insecurity is high or perception of side effects is strong. Conclusions This study shows that modification might be needed when using TPB constructs in resource constraint environments. Significance for public health The knowledge of the rates of adherence to antiretroviral therapy (ART) could be used to evaluate planning and project, which could lead to better outcomes predicted by treatment efficacy data. In addition, knowledge of adherence behaviour could help the development of interventions focusing on collaboration between healthcare providers and Malawian government to

  10. Effect of alumina composition and surface integrity in alumina/epoxy composites on the ultrasonic attenuation properties.

    PubMed

    Cho, Eikhyun; Park, Gwanwoo; Lee, Jae-Wan; Cho, Sung-Min; Kim, Taekyung; Kim, Joongeok; Choi, Wonjoon; Ohm, Won-Suk; Kang, Shinill

    2016-03-01

    We report a method of fabricating backing blocks for ultrasonic imaging transducers, using alumina/epoxy composites. Backing blocks contain scatterers such as alumina particles interspersed in the epoxy matrix for the effective scattering and attenuation of ultrasound. Here, the surface integrity can be an issue, where the composite material may be damaged during machining because of differences in strength, hardness and brittleness of the hard alumina particles and the soft epoxy matrix. Poor surface integrity results in the formation of air cavities between the backing block and the piezoelectric element upon assembly, hence the increased reflection off the backing block and the eventual degradation in image quality. Furthermore, with an issue of poor surface integrity due to machining, it is difficult to increase alumina as scatterers more than a specific mass fraction ratio. In this study, we increased the portion of alumina within epoxy matrix by obtaining an enhanced surface integrity using a net shape fabrication method, and verified that this method could allow us to achieve higher ultrasonic attenuation. Backing blocks were net-shaped with various mass fractions of alumina to characterize the formability and the mechanical properties, including hardness, surface roughness and the internal micro-structure, which were compared with those of machined backing blocks. The ultrasonic attenuation property of the backing blocks was also measured. PMID:26585217

  11. Ultrathin Alumina Film Al-Sublattice Structure, Metal Island Nucleation at Terrace Point Defects, and How Hydroxylation Affects Wetting

    SciTech Connect

    Bogicevic, A.; Jennison, D.R.

    1999-08-09

    In this paper, we include for discussion three topics of current interest in metal oxide surface science. Using first principles density functional theory (DFT) [1] calculations, we have investigated: (1) the atomic-scale structure of experimentally-relevant ultrathin alumina films, (2) the role of common point defects in metal island nucleation on oxide terraces, and (3) the growth and morphology of metals on oxide surfaces which have high concentrations of a common impurity.

  12. Modelling mesoporous alumina microstructure with 3D random models of platelets.

    PubMed

    Wang, H; Pietrasanta, A; Jeulin, D; Willot, F; Faessel, M; Sorbier, L; Moreaud, M

    2015-12-01

    This work focuses on a mesoporous material made up of nanometric alumina 'platelets' of unknown shape. We develope a 3D random microstructure to model the porous material, based on 2D transmission electron microscopy (TEM) images, without prior knowledge on the spatial distribution of alumina inside the material. The TEM images, acquired on samples with thickness 300 nm, a scale much larger than the platelets's size, are too blurry and noisy to allow one to distinguish platelets or platelets aggregates individually. In a first step, the TEM images correlation function and integral range are estimated. The presence of long-range fluctuations, due to the TEM inhomogeneous detection, is detected and corrected by filtering. The corrected correlation function is used as a morphological descriptor for the model. After testing a Boolean model of platelets, a two-scale model of microstructure is introduced to replicate the statistical dispersion of platelets observed on TEM images. Accordingly, a set of two-scale Boolean models with varying physically admissible platelets shapes is proposed. Upon optimization, the model takes into account the dispersion of platelets in the microstructure as observed on TEM images. Comparing it to X-ray diffraction and nitrogen porosimetry data, the model is found to be in good agreement with the material in terms of specific surface area. PMID:26280446

  13. Thermal Conductivity of Alumina and Silica Nanofluids

    NASA Astrophysics Data System (ADS)

    Castellanos, Julian G. Bernal

    This thesis studies the effects of the base fluid, particle type/size, and volumetric concentration on the thermal conductivity of Alumina and Silica nanofluids. The effects of base fluid were observed by preparing samples using ethylene glycol (EG), water, and mixtures of EG/water as the base fluid and Al2O3 (10 nm) nanoparticles. The particles type/size and volumetric concentration effects were tested by preparing samples of nanofluids using Al2O3 (10nm), Al2O3 (150nm), SiO2 (15 nm), and SiO2 (80 nm) nanoparticles and ionized water as base fluid at different volumetric concentrations. All samples were mixed using a sonicator for 30 minutes and a water circulator to maintain the sample at room temperature. The thermal conductivity was measured using a Thermtest Transient Plane Source TPS 500S. The effects of gravity, Brownian motion and thermophoresis were also studied. EG produced the highest thermal conductivity enhancement out of all base fluids tested. Smaller particle size produced a higher enhancement of thermal conductivity, while the volumetric concentration did not have a significant effect in the thermal conductivity enhancement. Finally, gravity, Brownian diffusion and thermophoresis effects played a role in the total enhancement of the thermal conductivity. The nanoparticles were observed to settle rapidly after sonication suggesting gravity effects may play a significant role.

  14. Mechanical properties of alumina porcelain during heating

    NASA Astrophysics Data System (ADS)

    Šín, Peter; Podoba, Rudolf; ŠtubÅa, Igor; Trník, Anton

    2014-11-01

    The mechanical strength and Young's modulus of green alumina porcelain (50 wt. % of kaolin, 25 wt. % of Al2O3, and 25 wt. % of feldspar) were measured during heating up to 900 °C and 1100 °C, respectively. To this end, we used the three point-bending method and modulated force thermomechanical analysis (mf-TMA). The loss liberation - of the physically bound water (20 - 250 °C) strengthens the sample and Young's modulus increases its values significantly. The dehydroxylation that takes place in the range of 400 - 650 °C causes a slight decrease in Young's modulus. On the other hand, the mechanical strength slightly increases in this temperature range, although it has a sudden drop at 420 °C. Beyond the dehydroxylation range, above 650 °C, both Young's modulus and mechanical strength increase. Above 950 °C, a sharp increase of Young's modulus is caused by the solid-state sintering and the new structure created by the high-temperature reactions in metakaolinite.

  15. Annealing Would Improve beta" - Alumina Solid Electrolyte

    NASA Technical Reports Server (NTRS)

    Williams, Roger; Homer, Margie; Ryan, Margaret; Cortez, Roger; Shields, Virgil; Kisor, Adam

    2003-01-01

    A pre-operational annealing process is under investigation as a potential means of preventing a sudden reduction of ionic conductivity in a Beta"-alumina solid electrolyte (BASE) during use. On the basis of tests, the sudden reduction of ionic conductivity, followed by a slow recovery, has been found to occur during testing of the solid electrolyte and electrode components of an alkali metal thermal-to-electric converter (AMTEC) cell. At this time, high-temperature tests of limited duration have indicated the superiority of the treated BASE, but reproducible tests over thousands of hours are necessary to confirm that microcracking has been eliminated. The ionic conductivity of the treated BASE is also measured to be higher than untreated BASE at 1,073 K in low-pressure sodium vapor. Microcracking resulting in loss of conductivity was not observed with treated BASE in one high-temperature experiment, but this result must be duplicated over very long testing times to be sure of the effect. Shorter annealing times (10 to 20 hours) were found to result in significantly less loss of mass; it may be necessary for the packed powder mixture to evolve some Na2O before the Na2O can leave the ceramic.

  16. Weight loss intervention adherence and factors promoting adherence: a meta-analysis

    PubMed Central

    Lemstra, Mark; Bird, Yelena; Nwankwo, Chijioke; Rogers, Marla; Moraros, John

    2016-01-01

    Background Adhering to weight loss interventions is difficult for many people. The majority of those who are overweight or obese and attempt to lose weight are simply not successful. The objectives of this study were 1) to quantify overall adherence rates for various weight loss interventions and 2) to provide pooled estimates for factors associated with improved adherence to weight loss interventions. Methods We performed a systematic literature review and meta-analysis of all studies published between January 2004 and August 2015 that reviewed weight loss intervention adherence. Results After applying inclusion and exclusion criteria and checking the methodological quality, 27 studies were included in the meta-analysis. The overall adherence rate was 60.5% (95% confidence interval [CI] 53.6–67.2). The following three main variables were found to impact adherence: 1) supervised attendance programs had higher adherence rates than those with no supervision (rate ratio [RR] 1.65; 95% CI 1.54–1.77); 2) interventions that offered social support had higher adherence than those without social support (RR 1.29; 95% CI 1.24–1.34); and 3) dietary intervention alone had higher adherence than exercise programs alone (RR 1.27; 95% CI 1.19–1.35). Conclusion A substantial proportion of people do not adhere to weight loss interventions. Programs supervising attendance, offering social support, and focusing on dietary modification have better adherence than interventions not supervising attendance, not offering social support, and focusing exclusively on exercise. PMID:27574404

  17. Effect of Zirconia and Alumina Fillers on the Microstructure and Mechanical Strength of Dental Glass Ionomer Cements

    PubMed Central

    Souza, Júlio C. M.; Silva, Joel B.; Aladim, Andrea; Carvalho, Oscar; Nascimento, Rubens M.; Silva, Filipe S.; Martinelli, Antonio E.; Henriques, Bruno

    2016-01-01

    Background: Glass-ionomer cements perform a protective effect on the dentin-pulp complex considering the F ions release and chemical bonding to the dental structures. On the other hand, those materials have poor physic-mechanical properties in comparison with the restorative resin composite. The main aim of this work was to evaluate the influence of zirconia and/or alumina fillers on the microstructure and strength of a resin modified glass-ionomer cement after thermal cycling. Methods: An in vitro experimental study was carried out on 9 groups (n = 10) of cylindrical samples (6 x 4 mm) made from resin modified glass-ionomer (Vitremer, 3M, USA) with different contents of alumina and/or zirconia fillers. A nano-hybrid resin composite was tested as a control group. Samples were mechanically characterized by axial compressive tests and electron scanning microscopy (SEM) coupled to energy dispersive X-ray spectrophotometry (EDS), before and after thermal cycling. Thermal cycling procedures were performed at 3000, 6000 and 10000 cycles in Fusayama´s artificial saliva at 5 and 60 oC. Results: An improvement of compressive strength was noticed on glass-ionomer reinforced with alumina fillers in comparison with the commercial glass ionomer. SEM images revealed the morphology and distribution of alumina or zirconia in the microstructure of glass-ionomers. Also, defects such as cracks and pores were detected on the glass-ionomer cements. The materials tested were not affected by thermal cycling in artificial saliva. Conclusion: Addition of inorganic particles at nano-scale such as alumina can increase the mechanical properties of glass-ionomer cements. However, the presence of cracks and pores present in glass-ionomer can negatively affect the mechanical properties of the material because they are areas of stress concentration. PMID:27053969

  18. Predictors and impact of non-adherence in adults with attention-deficit/hyperactivity disorder receiving OROS methylphenidate: results from a randomized, placebo-controlled trial

    PubMed Central

    2013-01-01

    Background Medication non-adherence has an important impact on treatment efficacy and healthcare burden across a range of conditions and therapeutic areas. The aim of this analysis was to determine predictors of non-adherence and impact of non-adherence on treatment response in adults with attention-deficit/hyperactivity disorder (ADHD). Methods Post-hoc analysis of a 13-week randomized, double-blind placebo-controlled study of OROS methylphenidate (MPH) 54 and 72 mg/day. Primary efficacy variable was the Conners’ Adult ADHD Rating Scale – Screening Version (CAARS:O-SV). Daily adherence was calculated as average daily adherence (100 × capsules taken/2), with overall adherence calculated as the average daily adherence. Predictors of adherence were assessed using mixed-effects logistic regression. Descriptive statistics were generated for change in CAARS:O-SV score for adherent (> 95% adherence) and non-adherent subjects. Predictors of change were analyzed using a mixed model. Results Subjects were allocated to OROS MPH (54 mg, n = 87; 72 mg, n = 92) or placebo (n = 97). Mean adherence was 92.6% and 93.3% (OROS MPH 54 and 72 mg/day, respectively), versus 97.5% (placebo). Adherence was higher and less variable in completers. Factors significantly associated with non-adherence included female sex, shorter time since ADHD diagnosis, higher education level (completion of university) and score on the Drug Use Screening Inventory psychiatric disorders subscale. Improvements from baseline in CAARS:O-SV score were numerically greater in subjects defined as adherent than in those who were non-adherent. Significant predictors of CAARS:O-SV change in patients who completed the study included percentage adherence up to the point of assessment (p < 0.0001), baseline score (p < 0.0001) and family history of ADHD (p = 0.0003). Conclusion The results of this analysis suggest that newly diagnosed patients, those with a high score on the DUSI-R psychiatric disorder scale, women

  19. Examination of particle/particle interactions and their impact on rheology and mixedness of an alumina/titania system

    NASA Astrophysics Data System (ADS)

    August, Cari R.

    In the manufacturing of ceramic particulate composites, improved manufacturing efficiency means two things, ease of production and increased performance. The effect of mixedness on the rheology of alumina-titania blends has been evaluated. Alumina and titania starting powders that have been examined ranged in particle size from nanoscale (50-200 nm) to micron scale (1-5 microm). Nano and micro-alumina powders have been combined individually with macro and micro-titania powders to determine how the nano/micro structure affects rheological properties and the mixedness of the final blended compositions. The effects of varying the mixing and processing techniques used to create the compositions; such as ball milling, wet mixing, high shear mixing, and varied mixing time, has been analyzed. The effect of varying surfactant additions (sodium stearate) on the mixedness and rheology of the alumina-titania blends has also been evaluated. The range of surfactant concentrations covers the measured adsorption limits of the particles in the blend, allowing sodium stearate to act not only as surfactant, but also as bulk lubricant. Rheological evaluation of these blends included torque, dynamic stress, and capillary rheometry. Dynamic stress rheometry measures and compares the viscous modulus and the shear modulus of a blend, allowing determination of its dynamic yield stress. Capillary rheometry was used to evaluate the extrusion pressures of the alumina-titania batches, for analysis with a Benbow-Bridgewater model, yielding information on extrusion wall stresses and extrudate bulk strength. The mixedness was evaluated by SEM-EDS method, which created a compositional map of a cross-sectional area of extrudate for distributional evaluation by nearest neighbor and standard deviation calculations. It was found that the use of nano-alumina and macro-titania increased processing requirements such as mixing energy and extrusion pressure, but produced extrudates with minimal flaws

  20. Processing and Characterizing Alumina/Aluminum Composites with Tailored Microstructures Formed by Reactive Metal Penetration

    SciTech Connect

    Corral, E.; Ellerby, D.; Ewsuk, K.; Fahrenholtz, B.; Loehman, R.

    1999-01-28

    In industry, the need to maximize energy efficiency depends on the availability of suitable advanced materials. Ceramic composites are exemplary materials for many advanced engineering applications because they exhibit good thermal stability, oxidation resistance and enhanced toughness. Presently, ceramic composite fabrication processes are costly, often requiring high temperatures and pressures to achieve reasonable densities. Our research is focused on developing a processing technique, that will allow production of alumina/aluminum composites using relatively low temperatures and without the application of an external force, thus reducing the processing costs. Our composites were formed using Reactive Metal Penetration (RMP), which is a process involving the reaction of molten Al with a dense ceramic preform. The result is a near net shape ceramic/metal composite with interpenetrating phases. The volume fraction of metal in the composites was varied by doping an aluminosilicate ceramic preform with silica. For this study we fabricated composites using pure mullite and mullite doped with 23 and 42 weight percent silica, yielding 18, 25, and 30 volume percent metal in the composites, respectively. Optical and Scanning Electron Microscopy were used to characterize the homogeneity and scale of the microstructure. The scale of the microstructure varied with preform composition, the reaction temperature and with secondary heat treatments. Four-point bend testing was used to evaluate the influence of microstructure on strength and reliability. During these studies a gradient in the microstructure was observed, which we further characterized using microhardness testing. Alumina/aluminum composites formed by RMP show higher toughness then monolithic alumina and have the potential for improved reliability when compared to monolithic ceramics.

  1. Ion polarization behavior in alumina under pulsed gate bias stress

    SciTech Connect

    Liu, Yu; Diallo, Abdou Karim; Katz, Howard E.

    2015-03-16

    Alkali metal ion incorporation in alumina significantly increases alumina capacitance by ion polarization. With high capacitance, ion-incorporated aluminas become promising high dielectric constant (high-k) gate dielectric materials in field-effect transistors (FETs) to enable reduced operating voltage, using oxide or organic semiconductors. Alumina capacitance can be manipulated by incorporation of alkali metal ions, including potassium (K{sup +}), sodium (Na{sup +}), and lithium (Li{sup +}), having different bond strengths with oxygen. To investigate the electrical stability of zinc tin oxide-based transistors using ion incorporated alumina as gate dielectrics, pulsed biases at different duty cycles (20%, 10%, and 2% representing 5 ms, 10 ms, and 50 ms periods, respectively) were applied to the gate electrode, sweeping the gate voltage over series of these cycles. We observed a particular bias stress-induced decrease of saturation field-effect mobility accompanied by threshold voltage shifts (ΔV{sub th}) in potassium and sodium-incorporated alumina (abbreviated as PA and SA)-based FETs at high duty cycle that persisted over multiple gate voltage sweeps, suggesting a possible creation of new defects in the semiconductor. This conclusion is also supported by the greater change in the mobility-capacitance (μC) product than in capacitance itself. Moreover, a more pronounced ΔV{sub th} over shorter times was observed in lithium-incorporated alumina (abbreviated as LA)-based transistors, suggesting trapping of electrons in existing interfacial states. ΔV{sub th} from multiple gate voltage sweeps over time were fit to stretched exponential forms. All three dielectrics show good stability using 50-ms intervals (20-Hz frequencies), corresponding to 2% duty cycles.

  2. Fatigue properties of atomic-layer-deposited alumina ultra-barriers and their implications for the reliability of flexible organic electronics

    NASA Astrophysics Data System (ADS)

    Baumert, E. K.; Pierron, O. N.

    2012-12-01

    The fatigue degradation properties of atomic-layer-deposited alumina, with thickness ranging from 4.2 to 50 nm, were investigated using a silicon micro-resonator on which the coatings were deposited and strained in a static or cyclic manner, with strain amplitudes up to 2.2%, in controlled environments. Based on the measured resonant frequency evolution, post-test scanning electron microscopy observations, and finite element models, it is shown that cracks in the alumina nucleate and propagate under cyclic loading, and that the crack growth rates scale with the strain energy release rates for crack channeling. The implications for the reliability of flexible electronics are discussed.

  3. Fatigue properties of atomic-layer-deposited alumina ultra-barriers and their implications for the reliability of flexible organic electronics

    SciTech Connect

    Baumert, E. K.; Pierron, O. N.

    2012-12-17

    The fatigue degradation properties of atomic-layer-deposited alumina, with thickness ranging from 4.2 to 50 nm, were investigated using a silicon micro-resonator on which the coatings were deposited and strained in a static or cyclic manner, with strain amplitudes up to 2.2%, in controlled environments. Based on the measured resonant frequency evolution, post-test scanning electron microscopy observations, and finite element models, it is shown that cracks in the alumina nucleate and propagate under cyclic loading, and that the crack growth rates scale with the strain energy release rates for crack channeling. The implications for the reliability of flexible electronics are discussed.

  4. Adherence to antiretroviral therapy and acceptability of planned treatment interruptions in HIV-infected children.

    PubMed

    Harrison, Linda; Ananworanich, Jintanat; Hamadache, Djamel; Compagnucci, Alexandra; Penazzato, Martina; Bunupuradah, Torsak; Mazza, Antonio; Ramos, Jose Tomas; Flynn, Jacquie; Rampon, Osvalda; Mellado Pena, Maria Jose; Floret, Daniel; Marczynska, Magdalena; Puga, Ana; Forcat, Silvia; Riault, Yoann; Lallemant, Marc; Castro, Hannah; Gibb, Diana M; Giaquinto, Carlo

    2013-01-01

    There have been no paediatric randomised trials describing the effect of planned treatment interruptions (PTIs) of antiretroviral therapy (ART) on adherence, or evaluating acceptability of such a strategy. In PENTA 11, HIV-infected children were randomised to CD4-guided PTIs (n = 53) or continuous therapy (CT, n = 56). Carers, and children if appropriate, completed questionnaires on adherence to ART and acceptability of PTIs. There was no difference in reported adherence on ART between CT and PTI groups; non-adherence (reporting missed doses over the last 3 days or marking <100 % adherence since the last clinical visit on a visual analogue scale) was 18 % (20/111) and 14 % (12/83) on carer questionnaires in the CT and PTI groups respectively (odds ratios, OR (95 % CI) = 1.04 (0.20, 5.41), χ(2) (1) = 0.003, p = 0.96). Carers in Europe/USA reported non-adherence more often (31/121, 26 %) than in Thailand (1/73, 1 %; OR (95 % CI) = 54.65 (3.68, 810.55), χ(2) (1) = 8.45, p = 0.004). The majority of families indicated they were happy to have further PTIs (carer: 23/36, 64 %; children: 8/13, 62 %), however many reported more clinic visits during PTI were a problem (carer: 15/36, 42 %; children: 6/12, 50 %). PMID:22584916

  5. Ultrafine alumina coated silicon carbide particles for alumina-silicon carbide nanocomposites

    SciTech Connect

    Warrier, K.G.K.; Hareesh, U.S.; Damodaran, A.D.

    1996-12-31

    Aluminum oxide, toughened by fine and uniform dispersion of silicon carbide particles has been found to possess interesting high temperature properties of high toughness and strength. Recent reports suggest that the finer the silicon carbide size, the better would be the fracture toughness. By addition of as few as 5 vol% submicron SiC particles strengthened Al{sub 2}O{sub 3} from 350 MPa to 1 GPa, with toughness as high as 4.7 Mpa m{sup {1/2}}. The mechanism of such high extent of fracture toughness has been investigated to be due to crack deflection and microcracking introduced by thermal expansion mismatch between particles and matrix grains, although the real contributions from the silicon carbide nanoparticles are still under investigation. In all these cases the primary requirement for most effective composite is the fine, uniform size of the particles and their homogeneous dispersion in the alumina matrix. Usual methods adopted for the preparation of composites such as physical mixing of alumina and silicon carbide particles often result in localized agglomerations and inhomogeneity making the composite inferior in properties.

  6. Adsorption and reaction of sulfur dioxide on alumina and sodium-impregnated alumina

    SciTech Connect

    Mitchell, M.B.; Sheinker, V.N.; White, M.G.

    1996-05-02

    The adsorption and oxidation of SO{sub 2} on alumina and sodium-impregnated alumina has been examined using thermogravimetric analysis and diffuse reflectance infrared Fourier transform spectroscopy. Sulfur dioxide chemisorbs initially at basic sites to form an adsorbed sulfite, which is quantitatively converted to sulfate on oxidation. It has been observed that at low coverages, nearly 2.6 {mu}mol/m{sup 2}, sodium acts as a promoter for the formation of an adsorbed sulfite and sulfate which have structures similar to those of aluminum sulfite and sulfate, respectively. At higher sodium loadings, a second type of adsorbed SO{sub 2} is formed, similar to sodium sulfite and sulfate. The species with the aluminum sulfate structure appears to be more easily decomposed than does the sodium sulfate species and accounts for the regenerable adsorption capacity. Formation of the sodium sulfate species appears to account for the loss of adsorption capacity as the number of adsorption/regeneration cycles increases. Oxidation of the sulfite form to the sulfate form can occur in the absence of added oxygen, but it is an activated process and begins to occur in measurable amounts at temperatures between 150 and 300{degree}C. Partitioning of adsorbed SO{sub 2} between aluminum and sodium forms is not a function of temperature and depends on only sodium loading. 32 refs., 14 figs., 1 tab.

  7. Assessment of adherence problems in patients with serious and persistent mental illness: recommendations from the Expert Consensus Guidelines.

    PubMed

    Velligan, Dawn I; Weiden, Peter J; Sajatovic, Martha; Scott, Jan; Carpenter, Daniel; Ross, Ruth; Docherty, John P

    2010-01-01

    Poor adherence to medication treatment can have devastating consequences for patients with serious mental illness. The literature review and recommendations in this article concerning assessment of adherence are reprinted from The Expert Consensus Guideline Series: Adherence Problems in Patients with Serious and Persistent Mental Illness, published in 2009. The expert consensus survey contained 39 questions (521 options) that asked about defining nonadherence, extent of adherence problems in schizophrenia and bipolar disorder, risk factors for nonadherence, assessment methods, and interventions for specific types of adherence problems. The survey was completed by 41 (85%) of the 48 experts to whom it was sent. When evaluating adherence, the experts considered it important to assess both behavior and attitude, although they considered actual behavior most important. They also noted the importance of distinguishing patients who are not willing to take medication from those who are willing but not able to take their medication as prescribed due to forgetfulness, misunderstanding of instructions, or financial or environmental problems, since this will affect the type of intervention needed. Although self- and physician report are most commonly used to clinically assess adherence, they are often inaccurate and may underestimate nonadherence. The experts believe that more accurate information will be obtained by asking about any problems patients are having or anticipate having taking medication rather than if they have been taking their medication; They also recommended speaking with family or caregivers, if the patient gives permission, as well as using more objective measures (e.g., pill counts, pharmacy records, smart pill containers if available, and, when appropriate, medication plasma levels). Use of a validated self-report scale may also help improve accuracy. For patients who appear adherent to medication, the experts recommended monthly assessments for

  8. Factors Influencing Antiretroviral Adherence and Virological Outcomes in People Living with HIV in the Highlands of Papua New Guinea.

    PubMed

    Gare, Janet; Kelly-Hanku, Angela; Ryan, Claire E; David, Matthew; Kaima, Petronia; Imara, Ulato; Lote, Namarola; Crowe, Suzanne M; Hearps, Anna C

    2015-01-01

    Adherence to antiretroviral therapy (ART) is paramount for virological suppression and positive treatment outcomes. ART has been rapidly scaled up in Papua New Guinea (PNG) in recent years, however clinical monitoring of HIV+ individuals on ART is limited. A cross-sectional study was conducted at two major sexual health clinics in high HIV prevalence provinces in the Highlands Region of PNG to assess ART adherence, factors affecting adherence and the relationship between ART adherence and virological outcomes. Ninety-five HIV+ individuals were recruited and administered a questionnaire to gather demographic and ART adherence information whilst clinical data and pill counts were extracted from patient charts and blood was collected for viral load testing. Bivariate analysis was performed to identify independent predictors of ART adherence. Fourteen percent (n = 12) of participants showed evidence of virological failure. Although the majority of participants self-reported excellent ART adherence in the last seven days (78.9%, 75/91), pill count measurements indicated only 40% (34/84) with >95% adherence in the last month. Taking other medications while on ART (p = 0.01) and taking ART for ≥1 year (p = 0.037) were positively associated with adherence by self-report and pill count, respectively. Participants who had never heard of drug resistance were more likely to show virological failure (p = 0.033). Misconception on routes of HIV transmission still persists in the studied population. These findings indicate that non-adherence to ART is high in this region of PNG and continued education and strategies to improve adherence are required to ensure the efficacy of ART and prevent HIV drug resistance. PMID:26244516

  9. The association between adherence to the New Nordic Diet and diet quality

    PubMed Central

    Bjørnarå, Helga Birgit; Øverby, Nina Cecilie; Stea, Tonje Holte; Torstveit, Monica Klungland; Hillesund, Elisabet Rudjord; Andersen, Lene Frost; Berntsen, Sveinung; Bere, Elling

    2016-01-01

    Background Previous studies have reported a positive association between scoring on healthy Nordic diet scales and the intake of healthy foods and nutrients, and also with higher intake of meat, sweets, cakes, and energy in general. These studies have used the same food frequency questionnaire (FFQ) responses for constructing the diet score as for calculating intakes of foods and nutrients. Thus, it is not clear whether the coexistence of healthy and less healthy dietary aspects among adherers to Nordic diets would occur even though separate methods were applied for exploring these relations. Objective To assess the association between adherence to the New Nordic Diet (NND), derived from an FFQ, and diet quality, determined from two 24-h dietary recall interviews. Design In total, 65 parents of toddlers in Southern Norway answered the NND FFQ and two 24-h dietary recall interviews. NND adherence was determined from the FFQ and categorized into low, medium, and high adherence. The two 24-h recalls provided data for the intake of specific foods and nutrients, selected on the basis of the Norwegian food-based guidelines as an indicator of a healthy diet. The Kruskal–Wallis test was used for assessing differences in food and nutrient intake across NND groups. Results High NND adherence derived from FFQ was associated with a high intake of fruits (p=0.004) and fiber (p=0.02), and a low intake of meat (p=0.004) and margarines (p=0.05), derived from recalls. A larger proportion of high NND adherers (68%) complied with the national dietary recommendation targeting meat intake compared with low NND adherers (29%) (p=0.04). Conclusion The present study showed that higher NND adherence measured with FFQ was associated with a higher intake of selected healthy foods and nutrients, measured with recalls. However, a higher intake of meat, sweets, and energy, as earlier reported, was not observed. PMID:27257844

  10. Complementary and Alternative Medication Use and Adherence to Inhaled Corticosteroid Among Inner-city Asthmatics

    PubMed Central

    Roy, Angkana; Lurslurchachai, Linda; Halm, Ethan A.; Li, Xiu-Min; Wisnivesky, Juan P.

    2009-01-01

    Background Complementary and alternative medicines (CAM) are used widely by patients with chronic diseases such as asthma. However, it is unclear whether use of CAM is associated with decreased adherence to inhaled corticosteroids (ICS), a key component of asthma management. Methods We surveyed 326 adults with persistent asthma receiving care at two inner-city outpatient clinics. Patients were asked about CAM use for treatment of asthma in the prior six months. Medication adherence was assessed using the Medication Adherence Report Scale, a validated self-report measure. Univariate and multiple regression analyses were used to assess the relationship between CAM use, adherence to ICS, and medication and disease beliefs. Results Overall, 25% (95% CI: 20–30%) of patients reported CAM use. Of those who used CAM, 39% (95% CI: 19–59%) discussed it with their physician, and 21% (95% CI: 12–31%) used CAM in place of prescribed asthma therapy. Univariate analyses showed that CAM use was associated with decreased ICS adherence and increased asthma morbidity. In multivariable analysis, CAM use was associated with lower ICS adherence (odds ratio [OR]: 0.5, 95% CI: 0.3–0.9) after adjusting for age, gender, race/ethnicity, education, years since diagnosis, language, and co-morbidities. CAM users were also more likely to worry about side effects of ICS (p=0.01). Conclusion CAM use was associated with decreased ICS adherence among inner-city asthmatics. Medication beliefs such as worry about ICS side effects may in part mediate this relationship. CAM use may be a marker for decreased adherence to ICS, particularly among patients with poor asthma control. PMID:20306816

  11. Adherence to Glycemic Monitoring in Diabetes

    PubMed Central

    Patton, Susana R.

    2015-01-01

    Glucose monitoring either by self-monitoring of blood glucose (SMBG) or continuous glucose monitoring (CGM) plays an important role in diabetes management and in reducing risk for diabetes-related complications. However, despite evidence supporting the role of glucose monitoring in better patient health outcomes, studies also reveal relatively poor adherence rates to SMBG and CGM use and numerous patient-reported barriers. Fortunately, some promising intervention strategies have been identified that promote at least short-term improvements in patients’ adherence to SMBG. These include education, problem solving, contingency management, goal setting, cognitive behavioral therapy, and motivational interviewing. Specific to CGM, interventions to promote greater use among patients are currently under way, yet one pilot study provides data suggesting better maintenance of CGM use in patients showing greater readiness for behavior change. The purpose of this review is to summarize the literature specific to glucose monitoring in patients with diabetes focusing specifically on current adherence rates, barriers to monitoring, and promising intervention strategies that may be ready to deploy now in the clinic setting to promote greater patient adherence to glucose monitoring. Yet, to continue to help patients with diabetes adhere to glucose monitoring, future research is needed to identify the treatment strategies and the intervention schedules that most likely lead to long-term maintenance of optimal glycemic monitoring levels. PMID:25591853

  12. Multidrug punch cards in primary care: a mixed methods study on patients' preferences and impact on adherence

    PubMed Central

    Boeni, Fabienne; Hersberger, Kurt E.; Arnet, Isabelle

    2014-01-01

    Background: Multidrug punch cards are frame cards with 28 plastic cavities filled with a patient's oral solid medication. They are used in primary care to facilitate medication management and to enhance adherence. Main criticism concerned handling difficulties and fading knowledge about medication of patients using them. This study aimed at exploring daily use, preferences, and adherence of primary care patients using multidrug punch cards. Methods: Community pharmacies in Switzerland recruited primary care patients using multidrug punch cards. A mixed methods approach was applied with quantitative interviews performed by telephone and qualitative interviews face-to-face. Results: Of 149 eligible patients from 21 community pharmacies, 22 participated 2011 in the quantitative and 11 participated 2013/14 in the qualitative interview. Patients were very satisfied with the multidrug punch cards and stated increased medication safety. All considered adherence as very important. Self-reported adherence was 10 (median) on a visual analog scale (0 = no intake, 10 = perfect adherence). The absence of package inserts and predefined handling difficulties e.g., tablets spiking at removal were not perceived as problems. Conclusions: Patients are satisfied with the multidrug punch cards, feel safe, mostly have no handling problems and adhere to their treatment. Trust in health-care professionals and patients' experiences emerged as key variables for initiating multidrug punch card use and for medication adherence. This mixed methods study invalidates previous concerns about disadvantages of multidrug punch cards. Health-care professionals should actively recommend them for primary care patients with polypharmacy and poor adherence. PMID:25324777

  13. Self-Assessment of Adherence to Medication: A Case Study in Campania Region Community-Dwelling Population

    PubMed Central

    Menditto, Enrica; Guerriero, Francesca; Orlando, Valentina; Crola, Catherine; Di Somma, Carolina; Illario, Maddalena; Morisky, Donald E.; Colao, Annamaria

    2015-01-01

    Objectives. The aim of the study was to assess self-reported medication adherence measure in patients selected during a health education and health promotion focused event held in the Campania region. The study also assessed sociodemographic determinants of adherence. Methods. An interviewer assisted survey was conducted to assess adherence using the Italian version of the 8-item Morisky Medication Adherence Scale (MMAS-8). Participants older than 18 years were interviewed by pharmacists while waiting for free-medical checkup. Results. A total of 312 participants were interviewed during the Health Campus event. A total of 187 (59.9%) had low adherence to medications. Pearson's bivariate correlation showed positive association between the MMAS-8 score and gender, educational level and smoking (P < 0.05). A multivariable analysis showed that the level of education and smoking were independent predictors of adherence. Individuals with an average level of education (odds ratio (OR), 2.21, 95% confidence interval (CI), 1.08–4.52) and nonsmoker (odds ratio (OR) 1.87, 95% confidence interval (CI), 1.04–3.35) were found to be more adherent to medication than those with a lower level of education and smoking. Conclusion. The analysis showed very low prescription adherence levels in the interviewed population. The level of education was a relevant predictor associated with that result. PMID:26346487

  14. Biocompatibility of atomic layer-deposited alumina thin films.

    PubMed

    Finch, Dudley S; Oreskovic, Tammy; Ramadurai, Krishna; Herrmann, Cari F; George, Steven M; Mahajan, Roop L

    2008-10-01

    Presented in this paper is a study of the biocompatibility of an atomic layer-deposited (ALD) alumina (Al2O3) thin film and an ALD hydrophobic coating on standard glass cover slips. The pure ALD alumina coating exhibited a water contact angle of 55 degrees +/- 5 degrees attributed, in part, to a high concentration of -OH groups on the surface. In contrast, the hydrophobic coating (tridecafluoro-1,1,2,2-tetrahydro-octyl-methyl-bis(dimethylamino)silane) had a water contact angle of 108 degrees +/- 2 degrees. Observations using differential interference contrast microscopy on human coronary artery smooth muscle cells showed normal cell proliferation on both the ALD alumina and hydrophobic coatings when compared to cells grown on control substrates. These observations suggested good biocompatibility over a period of 7 days in vitro. Using a colorimetric assay technique to assess cell viability, the cellular response between the three substrates can be differentiated to show that the ALD alumina coating is more biocompatible and that the hydrophobic coating is less biocompatible when compared to the control. These results suggest that patterning a substrate with hydrophilic and hydrophobic groups can control cell growth. This patterning can further enhance the known advantages of ALD alumina, such as conformality and excellent dielectric properties for bio-micro electro mechanical systems (Bio-MEMS) in sensors, actuators, and microfluidics devices. PMID:18085647

  15. Luminescence and IR characterization of acid sites on alumina

    SciTech Connect

    Shen, Yan-Fei; Suib, S.L. ); Deeba, M.; Koermer, G.S. )

    1994-04-01

    Luminescence and infrared (IR) spectroscopies of pyridine and ammonia adsorption have been used to measure acidities of [gamma]-alumina. Neither luminescence nor IR spectra of pyridine adsorption show an Bronsted acidity on [gamma]-alumina pretreated to 400[degrees]C. However, luminescence emission data reveal four weak OH bands even when pretreatment is done at 600[degrees]C. Pyridine and subsequent water adsorption yield six luminescence emission bands. A red shift of the pyridine emission band is found when pretreatment or desorption temperature is increased. IR spectra of ammonia on alumina pretreated at 400[degrees]C show three deformation bands at 1452, 1465, and 1485 cm[sup [minus]1]. The first band is also observed together with a band at 1554 cm[sup [minus]1] even for pretreatment at 950[degrees]C, and it corresponds to NH[sup +][sub 4] formed from dissociative adsorption of ammonia, while the other two bands are assigned to ammonia adsorbed on Bronsted acid sites. These two bands disappear along with the appearance of a new band at 1429 cm[sup [minus]1], when deuterated alumina is pretreated at 400[degrees]C and subsequently subjected to ammonia. This new band at 1429 cm[sup [minus]1] is due to NH[sub 3]D[sup +] formed from ammonia adsorbed on acidic OD sites. Consequently, ammonia IR results demonstrate the existence of Bronsted acid sites on alumina pretreated at 400[degrees]C. 38 refs., 9 figs., 2 tabs.

  16. Aluminas with dispersoids. Tribologic properties and in vivo aging.

    PubMed

    Mandrino, A; Moyen, B; Ben Abdallah, A; Treheux, D; Orange, D

    1990-07-01

    Three base alumina ceramics with dispersoids: monoclinic zirconia alumina (A5Z), tetragonal zirconia alumina (A20Z) and aluminalon (Aa20) have been investigated because of their improved mechanical properties with reference to pure alumina (AI203). Bending strength and fracture toughness are twice higher than alumina for the most toughened. These two parameters were measured by four-points bending tests after 1 week, 1, 2, 3, 6, 12 months of non loaded in vivo aging in wistar rats. They showed a little decrease for AI203 and Aa20 and a total stability for A5Z and A20Z even after one year. For tribologic study of the ceramic/polyethylene combination, cylinder against plane and pin on flat tests were conducted on an alternative movement with hip parameters of speed and load in presence of ringer solution. For the most representative test (pin on disk), the friction coefficients were nearly the same for all materials but UHMWPE wear volume was twice lower against A20Z than against AI203. A20Z/UHMWPE combination would be very interesting as new friction couple for total hip arthroplasty. Further studies are currently conducted. PMID:2397268

  17. The nature of hydrogen in γ-alumina

    SciTech Connect

    Li, Yunguo Lousada, Cláudio M. Korzhavyi, Pavel A.

    2014-05-28

    Gibbs free energy models are derived from the calculated electronic and phonon structure of two possible models of γ-alumina, a defective spinel phase and a hydrogenated spinel phase. The intrinsic vacancies and hydrogen in the two structural models give rise to a considerable configurational (residual) entropy and significantly contribute to thermodynamic stability and physical-chemical properties of γ-alumina, which was neglected in previous studies but considered in this work. The electronic densities of states, calculated using a hybrid functional for the two structural models of γ-alumina, are presented. The dynamic stability of the two phases is confirmed by full-spectrum phonon calculations. The two phases share many similarities in their electronic structure, but can be distinguished by their vibrational spectra and specific heat. The defective spinel is found to be the ground state of γ-alumina, while the hydrogenated spinel to be a metastable phase. However, dehydration of the metastable phase into the ground state is expected to be slow due to the low diffusion rate of H, which leaves hydrogen as a locked-in impurity in γ-alumina.

  18. Strategies to Increase Adherence through Diabetes Technology

    PubMed Central

    Gabbay, Robert A.; Durdock, Kendra

    2010-01-01

    A variety of new technologies have been developed to assist patients with self-managing their diabetes and yet hemoglobin A1c has not changed dramatically over the last decade. Although more data available from these new diabetes technologies can be helpful, it is clear that an informed, motivated, and adherent patient is the key to success. This article focuses on increasing patient adherence through the use of motivational interviewing, an evidence-based behavior change counseling technique. Specific skills of motivational interviewing may help the provider assess what the patient already knows about the technology, explore the patient's motivation for using the technology, and, finally, assess the patient's barriers, importance, and confidence in using the technology, leading to better adherence. PMID:20513334

  19. Strategies to increase adherence through diabetes technology.

    PubMed

    Gabbay, Robert A; Durdock, Kendra

    2010-05-01

    A variety of new technologies have been developed to assist patients with self-managing their diabetes and yet hemoglobin A1c has not changed dramatically over the last decade. Although more data available from these new diabetes technologies can be helpful, it is clear that an informed, motivated, and adherent patient is the key to success. This article focuses on increasing patient adherence through the use of motivational interviewing, an evidence-based behavior change counseling technique. Specific skills of motivational interviewing may help the provider assess what the patient already knows about the technology, explore the patient's motivation for using the technology, and, finally, assess the patient's barriers, importance, and confidence in using the technology, leading to better adherence. PMID:20513334

  20. Adherence of Clostridium thermocellum to cellulose.

    PubMed Central

    Bayer, E A; Kenig, R; Lamed, R

    1983-01-01

    The adherence of Clostridium thermocellum, a cellulolytic, thermophilic anaerobe, to its insoluble substrate (cellulose) was studied. The adherence phenomenon was determined to be selective for cellulose. The observed adherence was not significantly affected by various parameters, including salts, pH, temperature, detergents, or soluble sugars. A spontaneous adherence-defective mutant strain (AD2) was isolated from the wild-type strain YS. Antibodies were prepared against the bacterial cell surface and rendered specific to the cellulose-binding factor (CBF) by adsorption to mutant AD2 cells. By using these CBF-specific antibodies, crossed immunoelectrophoresis of cell extracts revealed a single discrete precipitation peak in the parent strain which was absent in the mutant. This difference was accompanied by an alteration in the polypeptide profile whereby sonicates of strain YS contained a 210,000-molecular-weight band which was missing in strain AD2. The CBF antigen could be removed from cell extracts by adsorption to cellulose. A combined gel-overlay--immunoelectrophoretic technique demonstrated that the cellulose-binding properties of the CBF were accompanied by carboxymethylcellulase activity. During the exponential phase of growth, a large part of the CBF antigen and related carboxymethylcellulase activity was associated with the cells of wild-type strain YS. However, the amounts decreased in stationary-phase cells. Cellobiose-grown mutant AD2 cells lacked the cell-associated CBF, but the latter was detected in the extracellular fluid. Increased levels of CBF were observed when cells were grown on cellulose. In addition, mutant AD2 regained cell-associated CBF together with the property of cellulose adherence. The presence of the CBF antigen and related adherence characteristics appeared to be a phenomenon common to other naturally occurring strains of this species. Images PMID:6630152

  1. A Review of Treatment Adherence Measurement Methods

    PubMed Central

    Schoenwald, Sonja K.; Garland, Ann F.

    2013-01-01

    Fidelity measurement is critical for testing the effectiveness and implementation in practice of psychosocial interventions. Adherence is a critical component of fidelity. The purposes of this review were to catalogue adherence measurement methods and assess existing evidence for the valid and reliable use of scores they generate and feasibility of use in routine care settings. Method A systematic literature search identified articles published between 1980–2008 reporting studies of evidence-based psychosocial treatments for child or adult mental health problems, and including mention of adherence or fidelity assessment. Coders abstracted data on the measurement methods and clinical contexts of their use. Results 341 articles were reviewed in which 249 unique adherence measurement methods were identified. These methods assessed many treatment models, although more than half (59%) assessed Cognitive Behavioral Treatments. The measurement methods were used in studies with diverse clientele and clinicians. The majority (71.5%) of methods were observational. Information about psychometric properties was reported for 35% of the measurement methods, but adherence-outcomes relationships were reported for only ten percent. Approximately one third of the measures were used in community- based settings. Conclusions Many adherence measurement methods have been used in treatment research; however, little reliability and validity evidence exists for the use of these methods. That some methods were used in routine care settings suggests the feasibility of their use in practice; however, information about the operational details of measurement, scoring, and reporting is sorely needed to inform and evaluate strategies to embed fidelity measurement in implementation support and monitoring systems. PMID:22888981

  2. [Challenges of adolescents' adherence to therapy].

    PubMed

    Brand, P L P; Kaptein, A A; Janssens, L P F; Klok, T

    2016-01-01

    Non-adherence occurs at any age, in all chronic diseases, and has a major impact on clinical outcomes. Non-adherence is primarily determined by perceptions of illness and medication beliefs. During puberty, adolescents attain independence from their parents and attach to their peers. This complicates successful self-management of chronic illness, because the adolescents avoid standing out from their peers. Discussion of barriers hindering successful self-management in adolescents can be promoted by seeing the patient alone, without the parents being present, and by acknowledging the patient's independence and responsibilities. PMID:27581866

  3. [Adherence to statins: updates and practical proposals].

    PubMed

    Bauwens, Marine; Schneider, Marie-paule; Nanchen, David

    2016-03-01

    Statins are an established treatment for dyslipidemia, because they were shown to decrease the cardiovascular risk by 25%. However, one third of patients using statins don't take them regularly. Statin intolerance is an important risk factor for nonadherence, but health literacy and lack of education regarding the cardiovascular benefits are also important triggers for poor adherence to statins. A better communication between the caregiver and his patient, by taking patient's perspectives into account could help find effective solutions. This article reviews the issue of statins adherence and suggests solutions to improve it. PMID:27089601

  4. Lower Permittivity Characteristic of Mesoporous-Alumina/Epoxy Composite due to Particle Porosity

    NASA Astrophysics Data System (ADS)

    Kurimoto, Muneaki; Murakami, Yoshinobu; Nagao, Masayuki

    Introduction of metal oxide nanoparticles to polymer composite material is known to have unique dielectric behavior and significant advantage in the electrical insulation performance of electrical power apparatus. This paper presents an attempt to derive the dielectric characteristics of polymer composite filled with the metal oxide particle which has mesoporous structure. Experiments were carried out in the epoxy composites filled with alumina microparticles which have the mesoporous structure (mesoporous-alumina/epoxy composites) with different particle content. Based on the measurement of the specific gravity of mesoporous-alumina/epoxy composites, the porosity of mesoporous-alumina particle in the epoxy matrix was found to be higher than that of nonporous-alumina particle. Furthermore, we evaluated relative permittivity of mesoporous-alumina/epoxy composites by measuring the capacitance of its specimens. As the results, we verified that the permittivity of mesoporous-alumina/epoxy composites was lower than that of nonporous-alumina/epoxy composites due to the particle porosity.

  5. Adherence to Cardiovascular Medications: Lessons Learned and Future Directions

    PubMed Central

    Kronish, Ian M; Ye, Siqin

    2013-01-01

    Approximately 50% of patients with cardiovascular disease and/or its major risk factors have poor adherence to their prescribed medications. Finding novel methods to help patients improve their adherence to existing evidence-based cardiovascular drug therapies has enormous potential to improve health outcomes while potentially reducing health care costs. The goal of this report is to provide a review of the current understanding of adherence to cardiovascular medications from the point of view of prescribing clinicians and cardiovascular researchers. Key topics addressed include: 1) definitions of medication adherence; 2) prevalence and impact of non-adherence; 3) methods for assessing medication adherence; 4) reasons for poor adherence; and 5) approaches to improving adherence to cardiovascular medications. For each of these topics, the report seeks to identify important gaps in knowledge and opportunities for advancing the field of cardiovascular adherence research. PMID:23621969

  6. Associations Between Self-Regulation, Exercise Participation, and Adherence Intention Among Korean University Students.

    PubMed

    Ahn, Jihoon; Jeon, Hyunsoo; Kwon, Sungho

    2016-08-01

    The social cognitive theory model of physical activity is useful in understanding and promoting exercise. Self-regulation, as an element of the social cognitive theory model, is key to success in regular exercise participation. Existing research suggests that intrinsic motivation and positive emotion are associated with exercise participation and adherence. This study examined the relationships between self-regulation and exercise participation and adherence intention in university students when these two variables were controlled. Participants included 418 students enrolled in universities in Seoul (244 men, M age = 23.5 year, SD = 0.8; 174 women, M age = 22.8 year, SD = 1.0). The measures included the Self-Control Scale, exercise participation level, the Korea Exercise Adherence Intention Scale, the Korean Sport Participation Motivation scale, and the Korean Positive and Negative Affect Scale. Results showed that self-regulation ability was significantly associated with exercise participation level and adherence intention, when intrinsic motivation and positive emotion were controlled. PMID:27450864

  7. Improving Fatigue Damage Resistance of Alumina through Surface Grading

    PubMed Central

    Ren, L.; Liu, L.; Bhowmick, S.; Gerbig, Y.B.; Janal, M.N.; Thompson, V.P.; Zhang, Y.

    2011-01-01

    Porcelain-veneered alumina crown restorations often fail from bulk fracture resulting from radial cracks that initiate at the cementation surface with repeated flexure of the stiffer crown layers on the soft dentin support. We hypothesized that bulk fracture may be substantially mitigated by grading the elastic modulus at the crown surfaces. In this study, we fabricated graded structures by infiltrating glass into dense alumina plates, resulting in a diminished modulus at the surface layers. The plates were then bonded to polycarbonate substrates and subjected to fatigue loading in water. Tests were terminated when fracture occurred at the cementation tensile surface or at the fatigue endurance limit (1 million cycles). Infiltrated specimens showed a significant increase in fatigue fracture loads over non-infiltrated controls. Our results indicate that controlled elastic gradients at the surface could be highly beneficial in the design of fracture-resistant alumina crowns. PMID:21555776

  8. Modifying alumina red mud to support a revegetation cover

    NASA Astrophysics Data System (ADS)

    Xenidis, A.; Harokopou, A. D.; Mylona, E.; Brofas, G.

    2005-02-01

    Alumina red mud, a fine-textured, iron-rich, alkaline residue, is the major waste product of bauxite digestion with caustic soda to remove alumina. The high alkalinity and salinity as well as the poor nutrient status are considered to be the major constraints of red mud revegetation. This research was conducted to evaluate the ameliorating effect of gypsum, sewage sludge, ferrous sulfate, ammonium sulfate, ammonium nitrate, and calcium phosphate on alumina red mud. The effectiveness of the mixtures was evaluated by applying extraction tests and performing experiments using six plant species. Gypsum amendment significantly reduced the pH, electrical conductivity, and sodium and aluminum content of red mud. Sewage sludge application had an extended effect in improving both the soil structure and the nutrient status of the gypsum-amended red mud. Together with the gypsum and sewage sludge, calcium phosphate application into red mud enhanced plant growth and gave the most promising results.

  9. Characteristics of alumina particles in dispersion-strengthened copper alloys

    NASA Astrophysics Data System (ADS)

    Zhang, Xue-hui; Li, Xiao-xian

    2014-11-01

    Two types of alumina dispersion-strengthened copper (ADSC) alloys were fabricated by a novel in-situ reactive synthesis (IRS) and a traditional internal oxidation (IO) process. The features of alumina dispersoids in these ADSC alloys were investigated by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. It is found that nano-sized γ-Al2O3 particles of approximately 10 nm in diameter are homogeneously distributed in the IRS-ADSC composites. Meanwhile, larger-sized, mixed crystal structure alumina with rod-shaped morphology is embedded in the IO-ADSC alloy. The IRS-ADSC composites can obtain better mechanical and physical properties than the IO-ADSC composites; the tensile strength of the IRS-ADSC alloy can reach 570 MPa at room temperature, its electrical conductivity is 85% IACS, and the Rockwell hardness can reach 86 HRB.

  10. Dynamic fragmentation of cellular, ice-templated alumina scaffolds

    NASA Astrophysics Data System (ADS)

    Tan, Yi Ming; Cervantes, Octavio; Nam, SeanWoo; Molitoris, John D.; Hooper, Joseph P.

    2016-01-01

    We examine the dynamic failure of ice-templated freeze-cast alumina scaffolds that are being considered as biomimetic hierarchical structures. Three porosities of alumina freeze-cast structures were fabricated, and a systematic variation in microstructural properties such as lamellar width and thickness was observed with changing porosity. Dynamic impact tests were performed in a light-gas gun to examine the failure properties of these materials under high strain-rate loading. Nearly complete delamination was observed following impact, along with characteristic cracking across the lamellar width. Average fragment size decreases with increasing porosity, and a theoretical model was developed to explain this behavior based on microstructural changes. Using an energy balance between kinetic, strain, and surface energies within a single lamella, we are able to accurately predict the characteristic fragment size using only standard material properties of bulk alumina.

  11. The surface reaction kinetics of salicylate on alumina

    SciTech Connect

    Wang, Z.; Ainsworth, C.C.; Friedrich, D.M.; Joly, A.G.; Gassman, P.L.

    1997-12-31

    The kinetics of reaction of salicylate with colloidal alumina in aqueous suspension and with Al(III) in homogeneous aqueous solution were studied by stopped-flow laser fluorescence spectroscopy. The emission spectra confirmed the formation of both monodentate complexes and more stable bidentate chelates. Temporal evolution of the spectra indicated that the reaction was fast (within first few minutes) for both the homogeneous and heterogeneous reactions but slowed down afterwards for the latter. Reactions completed within 10 minutes in homogeneous phase at pH 3.3 but took more than 12 hours in alumina suspension. Analysis of the fluorescence intensity within first four minutes showed that in homogeneous phase the reaction followed a single pseudo-first-order kinetics. In alumina suspension log plots were nonlinear and characteristic of multiple heterogeneous reaction paths. The kinetics are interpreted in terms of the simultaneous formation of multiple species as well as subsequent conversion between species.

  12. Fabrication of porous alumina templates for electrochemical synthesis of nanowires

    NASA Astrophysics Data System (ADS)

    Saidin, N. U.; Kok, Y. K.; Ng, I. K.; Ahmad Bustamam, F. K.; Zali, N. Mat; Zainal Abidin, S. S.

    2012-07-01

    Porous alumina membranes are often used as templates for synthesizing nanowire arrays due to their welldefined pore structures and uniform pore sizes. In this study, one-dimensional metallic nanowire arrays with wellcontrolled dimensions and structures were synthesized via template-directed electrodeposition using in-house fabricated alumina membranes as scaffolds. Porous alumina membranes with uniform nanoscale pore diameters and interpore distances were fabricated by a two-step anodisation technique. Pore diameters, depths as well as spacings between adjacent pores were carefully controlled by the anodizing conditions used. The morphologies and structures of the templates and the nanowires produced were reported using scanning electron microscopy (SEM) and X-ray diffraction for characterization.

  13. Molecular dynamics studies of interfacial water at the alumina surface.

    SciTech Connect

    Argyris, Dr. Dimitrios; Ho, Thomas; Cole, David

    2011-01-01

    Interfacial water properties at the alumina surface were investigated via all-atom equilibrium molecular dynamics simulations at ambient temperature. Al-terminated and OH-terminated alumina surfaces were considered to assess the structural and dynamic behavior of the first few hydration layers in contact with the substrates. Density profiles suggest water layering up to {approx}10 {angstrom} from the solid substrate. Planar density distribution data indicate that water molecules in the first interfacial layer are organized in well-defined patterns dictated by the atomic terminations of the alumina surface. Interfacial water exhibits preferential orientation and delayed dynamics compared to bulk water. Water exhibits bulk-like behavior at distances greater than {approx}10 {angstrom} from the substrate. The formation of an extended hydrogen bond network within the first few hydration layers illustrates the significance of water?water interactions on the structural properties at the interface.

  14. Plastic deformation and sintering of alumina under high pressure

    SciTech Connect

    Liu, Fangming; Liu, Pingping; Wang, Haikuo; Xu, Chao; Yin, Shuai; Yin, Wenwen; Li, Yong; He, Duanwei

    2013-12-21

    Plastic deformation of alumina (Al{sub 2}O{sub 3}) under high pressure was investigated by observing the shape changes of spherical particles, and the near fully dense transparent bulks were prepared at around 5.5 GPa and 900 °C. Through analyzing the deformation features, densities, and residual micro-strain of the Al{sub 2}O{sub 3} compacts prepared under high pressures and temperatures (2.0–5.5 GPa and 600–1200 °C), the effects of plastic deformation on the sintering behavior of alumina have been demonstrated. Under compression, the microscopic deviatoric stress caused by grain-to-grain contact could initiate the plastic deformation of individual particles, eliminate pores of the polycrystalline samples, and enhance the local atomic diffusion at the grain boundaries, thus produced transparent alumina bulks.

  15. Characterisation of alumina hip-joint wear by FIB Microscopy

    NASA Astrophysics Data System (ADS)

    Zeng, Peng; Inkson, Beverley J.; Rainforth, W. Mark

    2006-02-01

    The wear of hip-joints is a significant clinical problem, which causes adverse tissue reactions leading to bone absorption and consequent loosening of the fixation. Artificial hip joints retrieved after use and tested on simulators typically exhibit a 'stripe' wear area on the surface of the alumina bearing components. Focused Ion Beam (FIB) microscopy has been used to investigate the sub-surface damage mechanisms in worn alumina hip-joints for the first time. The alumina acetabular cup, both inside and outside the 'stripe' wear trace, has been cross-sectioned by FIB milling. The sub-surface microstructures revealed by the FIB machining, outside, inside and at the edge of the 'stripe' have been imaged by SEM and FIB and are compared with the microstructure of unworn bulk material. The advantage of this technique is that it enables site specific selected areas of the worn surface to be analysed.

  16. Thermal and Electrical Characterization of Alumina Substrate for Microelectronic Applications

    SciTech Connect

    Ahmad, S.; Ibrahim, A.; Alias, R.; Shapee, S. M.; Ambak, Z.; Zakaria, S. Z.; Yahya, M. R.; Mat, A. F. A.

    2010-03-11

    This paper reports the effect of sintering temperature on thermal and electrical properties of alumina material as substrate for microelectronic devices. Alumina materials in the form of green sheet with 1 mm thickness were sintered at 1100 deg. C, 1300 deg. C and 1500 deg. C for about 20 hours using heating and cooling rates of 2 deg. C/min. The densities were measured using densitometer and the microstructures of the samples were analyzed using SEM micrographs. Meanwhile thermal and electrical properties of the samples were measured using flash method and impedance analyzer respectively. It was found that thermal conductivity and thermal diffusivity of the substrate increases as sintering temperature increases. It was found also that the dielectric constant of alumina substrate increases as the sintering temperature increases.

  17. Studies on synthesis of alumina nanopowder from synthetic Bayer liquor

    SciTech Connect

    Mazloumi, Mahyar; Arami, Hamed; Khalifehzadeh, Razieh; Sadrnezhaad, S.K. . E-mail: sadrnezh@sharif.edu

    2007-06-05

    Procedure for synthesis of alumina nanopowder from Bayer liquor (synthetic sodium aluminate solution) is investigated. Cooling, ageing and then addition of 3 ml/l Tiron (1,2-dihydroxy-3,5-benzene disulfonic acid disodium salt) to the supersaturated liquor affect purity and fineness of the nanopowder product. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray (EDAX) analyses indicate that purity of the alumina nanopowder increases with the aging time. Experimental observations show that highly pure alumina nanopowders could be produced by direct calcination of cold gelatinous sodium aluminate solution followed by careful washing at a Tiron concentration of 3 ml/l NaOH.

  18. Sodium-beta Alumina Batteries: Status and Challenges

    SciTech Connect

    Lu, XC; Lemmon, JP; Sprenkle, V; Yang, ZG

    2010-09-01

    This paper provides a review of materials and designs for sodium-beta alumina battery technology and discusses the challenges ahead for further technology improvement. Sodium-beta alumina batteries have been extensively developed in recent years and encouraging progress in performance and cycle life has been achieved. The battery is composed of an anode, typically molten sodium, and a cathode that can be molten sulfur (Na-S battery) or a transition metal halide incorporated with a liquid phase secondary electrolyte (e.g.. ZEBRA battery). In most cases the electrolyte is a dense solid beta ''-Al(2)O(3), sodium ion-conducting membrane. The issues' prohibiting widespread commercialization of sodium-beta alumina technology are rekited to the materials and methods of manufacturing that impact cost, safety, and performance characteristics.

  19. Origin of high-alumina basalt, andesite, and dacite magmas

    USGS Publications Warehouse

    Hamilton, W.

    1964-01-01

    The typical volcanic rocks of most island arcs and eugeosynclines, and of some continental environments, are basalt, andesite, and dacite, of high alumina content. The high-alumina basalt differs from tholeiitic basalt primarily in having a greater content of the components of calcic plagioclase. Laboratory data indicate that in the upper mantle, below the level at which the basaltic component of mantle rock is transformed by pressure to eclogite or pyroxenite, the entire basaltic portion probably is melted within a narrow temperature range, but that above the level of that transformation plagioclase is melted selectively before pyroxene over a wide temperature range. The broad spectrum of high-alumina magmas may represent widely varying degrees of partial melting above the transformation level, whereas narrow-spectrum tholeiite magma may represent more complete melting beneath it.

  20. Origin of High-Alumina Basalt, Andesite, and Dacite Magmas.

    PubMed

    Hamilton, W

    1964-10-30

    The typical volcanic rocks of most island arcs and eugeosynclines, and of some continental environments, are basalt, andesite, and dacite, of high alumina content. The high-alumina basalt differs from tholeiitic basalt primarily in having a greater content of the components of calcic plagioclase. Laboratory data indicate that in the upper mantle, below the level at which the basaltic component of mantle rock is transformed by pressure to eclogite or pyroxenite, the entire basaltic portion probably is melted within a narrow temperature range, but that above the level of that transformation plagioclase is melted selectively before pyroxene over a wide temperature range. The broad spectrum of high-alumina magmas may represent widely varying degrees of partial melting above the transformation level, whereas narrow-spectrum tholeiite magma may represent more complete melting beneath it. PMID:17794034

  1. Alumina composites for oxide/oxide fibrous monoliths

    SciTech Connect

    Cruse, T. A.; Polzin, B. J.; Picciolo, J. J.; Singh, D.; Tsaliagos, R. N.; Goretta, K. C.

    2000-03-01

    Most work on ceramic fibrous monoliths (FMs) has focused on the Si{sub 3}N{sub 4}/BN system. In an effort to develop oxidation-resistant FMs, several oxide systems have recently been examined. Zirconia-toughened alumina and alumina/mullite appear to be good candidates for the cell phase of FMs. These composites offer higher strength and toughness than pure alumina and good high-temperature stability. By combining these oxides, possibly with a weaker high-temperature oxide as the cell-boundary phase, it should be possible to product a strong, resilient FM that exhibits graceful failure. Several material combinations have been examined. Results on FM fabrication and microstructural development are presented.

  2. Nanoscale electrochemical metallization memories based on amorphous (La, Sr)MnO3 using ultrathin porous alumina masks

    NASA Astrophysics Data System (ADS)

    Liu, Dongqing; Zhang, Chaoyang; Wang, Guang; Shao, Zhengzheng; Zhu, Xuan; Wang, Nannan; Cheng, Haifeng

    2014-02-01

    Nanoscale electrochemical metallization (ECM) memories based on amorphous La1-xSrxMnO3 (a-LSMO) were fabricated using ultrathin porous alumina masks. The ultrathin alumina masks, with thicknesses of about 200 nm and pore diameters of about 80 nm, were fabricated through a typical two-step anodization electrochemical procedure and transferred onto conductive Pt/Ti/SiO2/Si substrates. Resistive switching (RS) properties of the individual Ag/a-LSMO/Pt ECM cell were directly measured using a conductive atomic force microscope. The cells exhibited typical RS characteristics and the OFF/ON resistance ratio is as high as 102. Reproducible RS behaviours on the same ECM cell and the I-V cycles obtained from different ECM cells ensured that the RS properties in nanoscale Ag/a-LSMO/Pt cells are reproducible and reliable. This work provides an effective approach for the preparation of nanostructured large-scale ordered ECM memories or memristors.

  3. Alumina over-coating on Pd nanoparticle catalysts by atomic layer deposition : enhanced stability and reactivity.

    SciTech Connect

    Feng, H.; Lu, J.; Stair, P. C.; Elam, J. W.

    2011-04-01

    ALD Alumina was utilized as a protective layer to inhibit the sintering of supported nano-sized ALD Pd catalysts in the methanol decomposition reaction carried out at elevated temperatures. The protective ALD alumina layers were synthesized on Pd nanoparticles (1-2 nm) supported on high surface area alumina substrates. Up to a certain over-coat thickness, the alumina protective layers preserved or even slightly enhanced the catalytic activity and prevented sintering of the Pd nanoparticles up to 500 C.

  4. Hydrogen removal from e-beam deposited alumina thin films by oxygen ion beam

    SciTech Connect

    Das, Arijeet Mukharjee, C. Rajiv, K. Bose, Aniruddha Singh, S. D. Rai, S. K.; Ganguli, Tapas; Joshi, S. C.; Deb, S. K.; Phase, D. M.

    2014-04-24

    Hydrogen interstitials and oxygen vacancies defects create energy levels in the band gap of alumina. This limits the application of alumina as a high-k dielectric. A low thermal budget method for removal of hydrogen from alumina is discussed. It is shown that bombardment of alumina films with low energy oxygen ion beam during electron beam evaporation deposition decreases the hydrogen concentration in the film significantly.

  5. Factors contributing to the breakdown of sodium beta-alumina

    SciTech Connect

    Buechele, A.C.

    1982-05-01

    Clarification of the breakdown process occurring during charge transfer in sodium beta alumina solid electrolytes was derived from: (1) studying the effects of molten sodium contact at 350/sup 0/C on single crystal sodium beta alumina and polycrystalline sodium beta alumina; (2) determination of critical current density by monitoring acoustic emissions accompanying crack growth in sodium/sodium beta alumina/sodium cells subjected to linear current ramping at 1 mA cm/sup -2/ sec/sup -1/; (3) failure analysis conducted on cycled electrolytes, some from commercial sodium/sulfur cells, which had been subjected to up to 703 Ahr cm/sup -2/ of charge transfer. Gray coloration developing in beta aluminas in contact with molten sodium was found to be a consequence of formation, through reduction by sodium, of oxygen vacancies charge compensated by electrons. Electronic conductivity of the electrolyte increases as a result. No second phase formation was detected. Colored electrolytes from sodium/sulfur cells show evidence of a newly recognized degradation mechanism in which fracture occurs when sodium is reduced and deposited internally under pressure as metal in regions where an electronic conductivity gradient exists. Heating colored beta aluminas in air produces reoxidation and bleaching. Kinetics and other properties of the coloration and bleaching processes were determined. Critical current density was found to bear an inverse relation to average electrolyte grain size. Evidence was found in the cycled electrolytes for a slow crack growth mechanism and a progressive mode of degradation advancing from the sulfur electrode interface. Implications of the findings for the construction and operation of sodium/sulfur battery systems are discussed.

  6. Correlates of Adherence to Varenicline Among HIV+ Smokers

    PubMed Central

    Tseng, Tuo-Yen; Gonzalez, Mirelis; Krebs, Paul; Wong, Selena; Furberg, Robert; Sherman, Scott; Schoenthaler, Antoinette; Urbina, Anthony; Cleland, Charles M.

    2015-01-01

    Introduction: Low rates of adherence to smoking cessation pharmacotherapy may limit the effectiveness of treatment. However, few studies have examined adherence in smoking cessation trials thus, there is a limited understanding of factors that influence adherence behaviors. This brief report analyzes correlates of adherence to varenicline among people living with HIV/AIDS. Methods: Study participants were recruited from three HIV care centers in New York City and enrolled in a three-arm randomized controlled pilot study in which all subjects received varenicline. At the 1-month study visit, there were no significant differences in adherence by study condition, therefore we combined treatment arms to examine correlates of adherence (n = 127). We used pill counts to assess varenicline adherence, defined as taking at least 80% of the prescribed dose. We conducted a multivariate path analysis to assess factors proposed by the information-motivation-behavioral skills model to predict adherence. Results: Only 56% of smokers were at least 80% adherent to varenicline at 1 month. Adherence-related information, self-efficacy, a college degree, and non-Hispanic white race/ethnicity were associated with increased varenicline adherence. In path analysis, information and motivation were associated with increased adherence self-efficacy, and adherence self-efficacy was associated with increased adherence, but with marginal significance. These associations with adherence were no longer significant after controlling for race/ethnicity and education. Conclusions: Further exploration of the role of a modifiable correlates of adherence, such as adherence-related information, motivation and self-efficacy is warranted. Interventions are needed that can address disparities in these and other psychosocial factors that may mediate poor medication adherence. PMID:26180221

  7. Factors Affecting Non-Adherence among Patients Diagnosed with Unipolar Depression in a Psychiatric Department of a Tertiary Hospital in Kolkata, India

    PubMed Central

    Banerjee, Sohini

    2013-01-01

    Non-adherence to depression treatment is a common clinical problem globally. However, limited research is available from India. This cross-sectional study aimed to assess non-adherence to prescribed treatment among patients with unipolar depression at a psychiatric out-patient department (OPD) of a tertiary hospital in Kolkata, India. The Morisky Medication Adherence Scale (MMAS) was used and a questionnaire designed by the Principal Investigator (PI) was administered. A total of 239 patients with unipolar depression were interviewed of whom 66.9% (160) were non-adherent and 33.1% (79) were adherent to treatment. The difference was significant (Fisher's Exact <0.000). Women were nearly three times at a higher risk of being non-adherent compared to men (OR 2.7; 95% CI 1.0–7.1). The non-adherent group compared to the adherent group was significantly more likely to consume extra medicines than the recommended amount (OR 2.8; 95% CI 1.1–7.3) and had lower internal locus of control (LOC) (OR 4.5; 95% CI 2.4–8.3). Adherence to prescribed treatment in an out-patient clinical setting was a problem among patients with unipolar depression. Suitable interventions on individuals with the above mentioned attributes are required in India and in similar settings where non-adherence to depression therapy is an important public health problem. PMID:24381752

  8. Microseparation and stripe wear in alumina-on-alumina hip implants.

    PubMed

    Affatato, Saverio; Traina, Francesco; Toni, Aldo

    2011-06-01

    The combination of materials that still has highest wear resistance for total hip replacement is ceramic-on-ceramic. However, brittleness is a major concern for ceramics: in vivo and in vitro studies on ceramic hip prostheses correlate microseparation with hip noise, ceramic wear, or ceramic liner damage. Ceramic microseparation can lead to edge load, ceramic head wear, and squeaking. The aim of this in vitro study was to investigate whether different angles of inclination influence the wear pattern of alumina-on-alumina hip joints with micro-separation during the swing phase. We also evaluated the wear rate obtained from this in vitro investigation with retrieval specimens obtained at 13 years' mean follow-up. The study was performed using a 12-station hip joint wear simulator (Shore Western, Monrovia, CA, USA) under bovine calf serum used as lubricant. Wear was evaluated by the gravimetric method and the test length was set at two million cycles. After two million cycles, a volumetric loss of 0.11 ±0.03 mm3 and 0.12 ±0.06 mm3 was observed, respectively, for 23° and 63° angles of inclination. In particular, the results obtained in this work revealed an increase of about 12-fold compared to previous results without microseparation conditions. No significant differences were observed between the two different inclinations on the wear patterns of the acetabular cups with a level of significance of a = 0.5. The location and general shape of the stripes wear were similar for the retrieved and simulator balls. PMID:21725932

  9. Influence of grain boundary silica impurity on alumina toughness

    SciTech Connect

    Moya, J.S.; Kriven, W.M.; Pask, J.A.

    1980-08-01

    In a series of previous reports the effect of silica impurity on aggregation state and on electropheretic, pressing, filtering and sintering behavior on alumina powders was presented. The results obtained showed that the silica surface impurity plays an important role in the ceramic processing of powders by (a) decreasing the pH values of the isoelectric point (i.e.p.), which affects the aggregation state of the powder, and (b) decreasing the compactability and the activation energy for the initial stage of sintering. In the phase of the studies emphasis was given to the effect of the presence of silica impurity on the toughness and fracture behavior of alumina samples.

  10. The influence of aluminum grain size on alumina nanoporous structure

    SciTech Connect

    Feil, A. F.; Costa, M. V. da; Amaral, L.; Teixeira, S. R.; Migowski, P.; Dupont, J.; Machado, G.; Peripolli, S. B.

    2010-01-15

    An approach to control the interpore distances and nanopore diameters of 150-nm-thick thin aluminum films is reported here. The Al thin films were grown by sputtering on p-type silicon substrate and anodized with a conventional anodization process in a phosphoric acid solution. It was found that interpore distance and pore diameter are related to the aluminum grain size and can be controlled by annealing. The grain contours limit the sizes of alumina cells. This mechanism is valid for grain sizes supporting only one alumina cell and consequently only one pore.

  11. Atomistic force field for alumina fit to density functional theory

    SciTech Connect

    Sarsam, Joanne; Finnis, Michael W.; Tangney, Paul

    2013-11-28

    We present a force field for bulk alumina (Al{sub 2}O{sub 3}), which has been parametrized by fitting the energies, forces, and stresses of a large database of reference configurations to those calculated with density functional theory (DFT). We use a functional form that is simpler and computationally more efficient than some existing models of alumina parametrized by a similar technique. Nevertheless, we demonstrate an accuracy of our potential that is comparable to those existing models and to DFT. We present calculations of crystal structures and energies, elastic constants, phonon spectra, thermal expansion, and point defect formation energies.

  12. Partitioning of naphthalene to gemini surfactant-treated alumina.

    PubMed

    Neupane, D; Park, J W

    2000-09-01

    Partitioning of naphthalene to anionic surfactants adsorbed on alumina in the aqueous phase was studied for immobilization of the contaminant in the subsurface. Three anionic surfactants with different molecular structures were used: a conventional (sodium dodecylbenzene sulfonate, SDDBS), a gemini (dialkylated disulfonated diphenyl oxide with alkyl chain length of 12, DADS-C12), and a dianionic (monoalkylated disulfonated diphenyl oxide with alkyl chain length of 12, MADS-C12). Sorption of the surfactants onto alumina was studied in a series of batch experiments and the effectiveness of the adsorbed surfactants onto aluminum oxide as a sorptive phase for naphthalene was compared. PMID:10834382

  13. Nanowatt threshold, alumina sensitized neodymium laser integrated on silicon

    PubMed Central

    Maker, Ashley J.; Armani, Andrea M.

    2013-01-01

    Low threshold lasers based on rare-earth elements have enabled numerous scientific discoveries and innovations in industry. However, pushing the threshold into the sub-microwatt regime has been stymied by a fundamental material phenomenon. Specifically, rare earth dopants form clusters which quench emission and reduce efficiency. Here, we fabricate resonant cavity lasers from neodymium-doped silica films containing alumina. The alumina prevents the clustering of the Neodymium, enabling the lasers to achieve thresholds of 530nanoWatts at room temperature. PMID:24216946

  14. Medication adherence in patients in treatment for rheumatoid arthritis and systemic lupus erythematosus in a university hospital in Brazil

    PubMed Central

    Prudente, Luciana Resende; Diniz, Juliana de Souza; Ferreira, Tatyana Xavier Almeida Matteucci; Lima, Dione Marçal; Silva, Nílzio Antônio; Saraiva, Guylherme; Silveira, Erika Aparecida; Dewulf, Nathalie de Lourdes Souza; Amaral, Rita Goreti

    2016-01-01

    Medication adherence is essential for the control of symptoms and progression of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). The aim of the study was to investigate medication adherence in outpatients in treatment for RA and SLE in a university hospital in Brazil. This was a quantitative, cross-sectional analytical study. A total of 92 patients (55 RA patients and 37 SLE patients) were included in the study. A structured questionnaire for patients’ interview and a form for collecting data from medical records were used for data collection. Adherence to drug treatment was assessed by the Morisky scale questionnaire. Data storage and analysis were performed using Epi Info 3.5.4 and statistical analysis by Stata/SE 12.0. The Pearson’s chi-squared test and Fisher’s exact test were applied for statistical and bivariate analyses. For multivariate data analysis the Poisson regression and the Wald test were used. The prevalence of adherence to drug treatment was 16.4% in RA patients and 45.9% in SLE patients. The final model of the multivariate analysis demonstrated associations between medication adherence and the following covariates for both RA and SLE groups: duration of therapy for rheumatic disease at the institution greater than 15 years and presence of more than six chronic comorbidities. The parameter “acquisition of medication at the high-cost pharmacy” was differently associated with medication adherence by group, and for the SLE group, living outside the city of Goiânia was a protective factor associated with adherence. This study demonstrated a low prevalence of medication adherence in patients in treatment for RA and SLE treated at this institution. These findings will serve as a base for future studies to elucidate what factors may positively or negatively affect medication adherence in this population. In addition, multidisciplinary approaches are needed to enhance adherence to drug treatment in patients in treatment for

  15. E-health strategies to support adherence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adherence to healthy behaviors and self-care strategies is a concern among clinicians. E-health applications, such as the internet, personal communication devices, electronic health records and web portals, and electronic games, may be a way to provide health information in a way that is reliable, c...

  16. Adherence to Exercise and Physical Activity: Preface.

    ERIC Educational Resources Information Center

    Morgan, William P.; Dishman, Rod K.

    2001-01-01

    Introduces a collection of papers on adherence to exercise programs and physical activity from the 2000 American Academy of Kinesiology and Physical Education conference, which included research on middle school boys and girls, college men and women, and men and women in the later years, as well as on the more traditional subject of middle aged…

  17. Quality of life associated with treatment adherence in patients with type 2 diabetes: a cross-sectional study

    PubMed Central

    Martínez, Yolanda V; Prado-Aguilar, Carlos A; Rascón-Pacheco, Ramón A; Valdivia-Martínez, José J

    2008-01-01

    Background Despite certain contradictions, an association has been identified between adherence to drug treatment and the quality of life in patients with type 2 diabetes. The contradictions observed emphasize the importance of using different methods to measure treatment adherence, or the association of psychological precursors of adherence with quality of life. For this reason, we have used an indirect method to measure adherence (pill count), as well as two adherence behaviour precursors (attitude and knowledge), to assess the association between adherence and the quality of life in type 2 diabetes patients. Methods A cross-sectional comparative study on a random sample of 238 type 2 diabetic patients was carried out over one year in four family medicine units of the Mexican Institute of Social Security (IMSS) in Aguascalientes, Mexico. Treatment adherence was measured using the indirect method of pill count to assess adherence behaviour, obtaining information at two home visits. In the first we recorded the medicine prescribed and in the second, we counted the medicine remaining to determine the proportion of the medicine taken. We also assessed two adherence behaviour precursors: the patients' knowledge regarding their medical prescription measured through a structured questionnaire; and attitudes to treatment adherence using a Likert scale. Quality of life was measured through the WHOQOL-100 (the WHO Quality of Life questionnaire). Information concerning both knowledge and attitude was obtained through interviews with the patients. A multiple linear regression model was constructed to establish the relationship between each quality of life domain and the variables related to adherence, controlling for covariates. Results There was no association between quality of life and treatment adherence behaviour. However, the combination of strong knowledge and a positive attitude was associated with five of the six quality of life domains. Conclusion The results

  18. Medication adherence in the asthmatic child and adolescent.

    PubMed

    Desai, Mauli; Oppenheimer, John J

    2011-12-01

    Asthma is a common inflammatory condition affecting more than 7 million children in the United States alone, and tens of millions more globally. Despite effective preventive medications, medication nonadherence in children and adolescents is alarmingly high. Nonadherence can result in poor asthma control, which leads to decreased quality of life, lost productivity, increased health care utilization, and even the risk of death. Nonadherence in children and adolescents deserves special attention because they face unique barriers to adherence that change with age. Young children depend on adults for the delivery of asthma care, and their care is strongly influenced by parental motivation and attitudes and the home environment. As these children enter adolescence, they typically assume responsibility for their asthma care at the same time that they are claiming their independence and possibly experimenting with high-risk behaviors. Morbidity and mortality, as well as nonadherence, appear to be greatest among adolescents and minority children. Although no perfect tool for measuring adherence exists, objective methods, such as electronic monitoring, can provide valuable information to health care providers. Beyond asthma self-management and education, no specific resource-heavy adherence interventions have proven consistently helpful. However, large-scale, well-designed studies on this subject are lacking. In light of the fact that nonadherence is a potentially modifiable factor that impacts on morbidity and mortality, it is worth pursuing further research to determine better interventions. It is likely, however, that no one answer exists, and interventions will need to be tailored to specific at-risk populations. PMID:21968618

  19. Final report on the application of chaos theory to an alumina sensor for aluminum reduction cells. Inert Electrodes Program

    SciTech Connect

    Williford, R.E.; Windisch, C.F. Jr.

    1992-03-01

    Four chaos-related digital signal analysis (DSA) methods were applied to the analysis of voltage and current signals collected from aluminum electrolysis cells. Two separate data bases were analyzed: bench-scale laboratory experiments and a pilot-scale test. The objective was to assess the feasibility of using these types of data and analysis methods as the basis for a non-intrusive sensor to measure the alumina content in the electrolysis bath. This was the first time chaos theory approaches have been employed to analyze aluminum electrolysis cells.

  20. The nanostructure effect on the adhesion and growth rates of epithelial cells with well-defined nanoporous alumina substrates.

    PubMed

    Chung, S H; Son, S J; Min, J

    2010-03-26

    We systematically analyzed the adhesion and the proliferation of cells on various nanoporous alumina surfaces to understand the effects of nanostructured surfaces on cell behavior. Various nanoporous surfaces were fabricated using the anodizing method and characterized by atomic force microscopy and scanning electron microscopy. The adhesion rate and proliferation rate of cells as functions of pore size and depth were statistically investigated using a colorimetric method. The adhesion rate of cells was not affected by the depth of the nanoporous surface whereas the proliferation of cells dramatically increased when the aspect ratio of the nanopore was near unity. This phenomenon was further verified by comparing the change in roughness of the cytoplasmic layer of cells adhered on a nanoporous surface with that of a bare nanoporous surface. The proliferation of cells was also influenced by the pore size of the nanoporous surface because the nanostructure could control the interaction between extracellular matrix (ECM) molecules and the surface. In conclusion, the nanostructured surfaces affected cell adhesion and proliferation by increasing the surface area to which the cells could adhere, and the interactions between small ECM molecules were influenced by the sufficiently small structures of the nanosurface. PMID:20195010

  1. Variation in medication adherence across patient behavioral segments: a multi-country study in hypertension

    PubMed Central

    Sandy, Robert; Connor, Ulla

    2015-01-01

    Objectives This study determines the following for a hypertensive patient population: 1) the prevalence of patient worldview clusters; 2) differences in medication adherence across these clusters; and 3) the adherence predictive power of the clusters relative to measures of patients’ concerns over their medication’s cost, side effects, and efficacy. Methods Members from patient panels in the UK, Germany, Italy, and Spain were invited to participate in an online survey that included the Medication Adherence Report Scale-5 (MARS-5) adherence instrument and a patient segmentation instrument developed by CoMac Analytics, Inc, based on a linguistic analysis of patient talk. Subjects were screened to have a diagnosis of hypertension and treatment with at least one antihypertensive agent. Results A total of 353 patients completed the online survey in August/September 2011 and were categorized against three different behavioral domains: 1) control orientation (n=176 respondents [50%] for I, internal; n=177 respondents [50%] for E, external); 2) emotion (n=100 respondents [28%] for P, positive; n=253 respondents [72%] for N, negative); and 3) agency or ability to act on choices (n=227 respondents [64%] for H, high agency; n=126 [36%] for L, low agency). Domains were grouped into eight different clusters with EPH and IPH being the most prevalent (88 respondents [25%] in each cluster). The prevalence of other behavior clusters ranged from 6% (22 respondents, INH) to 12% (41 respondents, IPL). The proportion of patients defined as perfectly adherent (scored 25 on MARS-5) varied sharply across the segments: 51% adherent (45 of 88 respondents) for the IPH vs 8% adherent (2 of 25 respondents) classified as INL. Side effects, being employed, and stopping medicine because the patient got better were all significant determinants of adherence in a probit regression model. Conclusion By categorizing patients into worldview clusters, we identified wide differences in adherence that

  2. A practical approach for measurement of antihypertensive medication adherence in patients with resistant hypertension.

    PubMed

    Corrêa, Nathália Batista; de Faria, Ana Paula; Ritter, Alessandra M V; Sabbatini, Andrea Rodrigues; Almeida, Aurélio; Brunelli, Veridiana; Calhoun, David A; Moreno, Heitor; Modolo, Rodrigo

    2016-06-01

    Confirmation of medication adherence is a challenge in clinical practice and essential for the accurate diagnosis of resistant hypertension. Although it is well established that drug adherence is critical for controlling blood pressure, there are still difficulties applying a simple, inexpensive, and reliable assessment of adherence in the clinical setting. We aimed to test a simple method to assess adherence in resistant hypertensive (RH) patients. A pilot study with normotensives or mild/moderate hypertensive subjects was performed to provide a fluorescence cutoff point for adherence. After that, 21 patients referred to the Resistant Hypertension Clinic had triamterene prescribed and were monitored for a 30-day period. We conducted two unannounced randomly selected home visits for urine collection to test drug intake that day. Office, home and 24-hour ambulatory blood pressure, biochemical data, and the 8-item Morisky Medication Adherence Scale (MMAS-8) were systematically acquired. According to adherence indicated by urine fluorescence, subjects were divided into adherent and nonadherent groups. We found 57% of nonadherence. No differences were found between groups regarding baseline characteristics or prescribed medications; Kappa's test showed concordance between adherence through MMAS-8 items and fluorescence (kappa = 0.61; 95% confidence interval: 0.28-0.94; P = .005). Nonadherent patients had higher office (81 ± 11 vs. 73 ± 6 mm Hg, P = .03), 24-hour ambulatory blood pressure monitoring (75 ± 9 vs. 66 ± 7 mm Hg, P = .01), and home blood pressure measurement (77 ± 9 vs. 67 ± 8 mm Hg, P = .01) diastolic blood pressure than their counterparts. Nonadherence to antihypertensive therapy is high in patients with RH, even when assessed in clinics specialized in this condition. Fluorometry to detect a drug in the urine of RH patients is safe, easy, and reliable method to assess adherence. PMID:27161936

  3. Adherent Use of Digital Health Trackers Is Associated with Weight Loss.

    PubMed

    Pourzanjani, Arya; Quisel, Tom; Foschini, Luca

    2016-01-01

    We study the association between weight fluctuation and activity tracking in an on-line population of thousands of individuals using digital health trackers (1,749 ≤ N ≤ 14,411, depending on the activity tracker considered) with millions of recorded activities (119,292 ≤ N ≤ 2,221,382) over the years 2013-2015. In a first between-subject analysis, we found a positive association between activity tracking frequency and weight loss. Users who log food with moderate frequency lost an additional 0.63% (CI [0.55, 0.72]; p < .001) of their body weight per month relative to low frequency loggers. Frequent workout loggers lost an additional 0.38% (CI [0.20, 0.56]; p < .001) and frequent weight loggers lost an additional 0.40% (CI [0.33, 0.47]; p < .001) as compared to infrequent loggers. In a subsequent within-subject analysis on a subset of the population (799 ≤ N ≤ 6,052) with sufficient longitudinal data, we used fixed effect models to explore the temporal relationship between a change in tracking adherence and weight change. We found that for the same individual, weight loss is significantly higher during periods of high adherence to tracking vs. periods of low adherence: +2.74% of body weight lost per month (CI [2.68, 2.81]; p < .001) during adherent weight tracking, +1.35% per month (CI [1.26, 1.43]; p < .001) during adherent food tracking, and +0.60% per month (CI [0.44, 0.76]; p < .001) during adherent workout tracking. The findings suggest that adherence to activity tracking can be utilized as a convenient real-time predictor of weight fluctuations, enabling large-scale, personalized intervention strategies. PMID:27049859

  4. Adherent Use of Digital Health Trackers Is Associated with Weight Loss

    PubMed Central

    Pourzanjani, Arya; Quisel, Tom; Foschini, Luca

    2016-01-01

    We study the association between weight fluctuation and activity tracking in an on-line population of thousands of individuals using digital health trackers (1,749 ≤ N ≤ 14,411, depending on the activity tracker considered) with millions of recorded activities (119,292 ≤ N ≤ 2,221,382) over the years 2013–2015. In a first between-subject analysis, we found a positive association between activity tracking frequency and weight loss. Users who log food with moderate frequency lost an additional 0.63% (CI [0.55, 0.72]; p < .001) of their body weight per month relative to low frequency loggers. Frequent workout loggers lost an additional 0.38% (CI [0.20, 0.56]; p < .001) and frequent weight loggers lost an additional 0.40% (CI [0.33, 0.47]; p < .001) as compared to infrequent loggers. In a subsequent within-subject analysis on a subset of the population (799 ≤ N ≤ 6,052) with sufficient longitudinal data, we used fixed effect models to explore the temporal relationship between a change in tracking adherence and weight change. We found that for the same individual, weight loss is significantly higher during periods of high adherence to tracking vs. periods of low adherence: +2.74% of body weight lost per month (CI [2.68, 2.81]; p < .001) during adherent weight tracking, +1.35% per month (CI [1.26, 1.43]; p < .001) during adherent food tracking, and +0.60% per month (CI [0.44, 0.76]; p < .001) during adherent workout tracking. The findings suggest that adherence to activity tracking can be utilized as a convenient real-time predictor of weight fluctuations, enabling large-scale, personalized intervention strategies. PMID:27049859

  5. Medication adherence and quality of life among the elderly with diabetic retinopathy 1

    PubMed Central

    Jannuzzi, Fernanda Freire; Cintra, Fernanda Aparecida; Rodrigues, Roberta Cunha Matheus; São-João, Thaís Moreira; Gallani, Maria Cecília Bueno Jayme

    2014-01-01

    OBJECTIVE: to investigate the factors related to medication adherence and its relation to Health- Related Quality of Life (HRQoL) in elderly people with diabetic retinopathy. METHOD: one hundred (n=100) elderly outpatients with diabetic retinopathy taking antihypertensives and/or oral antidiabetics/insulin were interviewed. Adherence was evaluated by the adherence proportion and its association with the care taken in administrating medications and by the Morisky Scale. The National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) was used to evaluate HRQoL. RESULTS: most (58%) reported the use of 80% or more of the prescribed dose and care in utilizing the medication. The item "stopping the drug when experiencing an adverse event", from the Morisky Scale, explained 12.8% and 13.5% of the variability of adherence proportion to antihypertensives and oral antidiabetics/insulin, respectively. CONCLUSION: there was better HRQoL in the Color Vision, Driving and Social Functioning domains of the NEI VFQ-25. Individuals with lower scores on the NEI VFQ-25 and higher scores on the Morisky Scale presented greater chance to be nonadherent to the pharmacological treatment of diabetes and hypertension. PMID:25591084

  6. Standard measures are inadequate to monitor pediatric adherence in a resource-limited setting.

    PubMed

    Müller, Alexandra D; Jaspan, Heather B; Myer, Landon; Hunter, Ashley Lewis; Harling, Guy; Bekker, Linda-Gail; Orrell, Catherine

    2011-02-01

    This study aims to compare the use and cost of objective and subjective measures of adherence to pediatric antiretroviral treatment in a primary care facility in South Africa. In a 1-month longitudinal study of 53 caregiver-child dyads, pharmacy refill (PR), measurement of returned syrups (RS), caregiver self-report (3DR) and Visual Analogue Scale (VAS) were compared to Medication Event Monitoring System (MEMS). Adherence was 100% for both VAS and 3DR; by PR and RS 100% and 103%, respectively. MEMS showed that 92% of prescribed doses were administered, but only 66% of these within the correct 12-hourly interval. None of the four measures correlated significantly with MEMS. MEMS data suggest that timing of doses is often more deviant from prescribed than expected and should be better addressed when monitoring adherence. Of all, MEMS was by far the most expensive measure. Alternative, cheaper electronic devices need to be more accessible in resource-limited settings. PMID:20953692

  7. Clinical Supervision in Treatment Transport: Effects on Adherence and Outcomes

    PubMed Central

    Schoenwald, Sonja K.; Sheidow, Ashli J.; Chapman, Jason E.

    2009-01-01

    This non-experimental study used Mixed-Effects Regression Models (MRMs) to examine relations among supervisor adherence to a clinical supervision protocol, therapist adherence, and changes in the behavior and functioning of youth with serious antisocial behavior treated with an empirically supported treatment (i.e., Multisystemic Therapy), one-year post treatment. Participants were 1979 youth and families treated by 429 clinicians across 45 provider organizations in North America. Four dimensions of clinical supervision were examined. MRM results showed one dimension, supervisor focus on adherence to treatment principles, predicted greater therapist adherence. Two supervision dimensions, adherence to the structure and process of supervision, and focus on clinician development, predicted changes in youth behavior. Conditions required to test hypothesized mediation by therapist adherence of supervisor adherence effects on youth outcomes were not met, and direct effects of each were observed in models including both supervisor and therapist adherence. PMID:19485583

  8. Medication Adherence in Patients with Bipolar Disorder: A Comprehensive Review.

    PubMed

    Levin, Jennifer B; Krivenko, Anna; Howland, Molly; Schlachet, Rebecca; Sajatovic, Martha

    2016-09-01

    Poor medication adherence is a pervasive problem that causes disability and suffering as well as extensive financial costs among individuals with bipolar disorder (BD). Barriers to adherence are numerous and cross multiple levels, including factors related to bipolar pathology and those unique to an individual's circumstances. External factors, including treatment setting, healthcare system, and broader health policies, can also affect medication adherence in people with BD. Fortunately, advances in research have suggested avenues for improving adherence. A comprehensive review of adherence-enhancement interventions for the years 2005-2015 is included. Specific bipolar adherence-enhancement approaches that target knowledge gaps, cognitive patterns, specific barriers, and motivation may be helpful, as may approaches that capitalize on technology or novel drug-delivery systems. However, much work remains to optimally facilitate long-term medication adherence in people with BD. For adherence-enhancement approaches to be widely adapted, they need to be easily accessible, affordable, and practical. PMID:27435356

  9. Treatment Adherence in Adolescents With Inflammatory Bowel Disease: The Collective Impact of Barriers to Adherence and Anxiety/Depressive Symptoms

    PubMed Central

    Gray, Wendy N.; Denson, Lee A.; Baldassano, Robert N.

    2012-01-01

    Objective Knowledge of factors impacting adolescents’ ability to adhere to their inflammatory bowel disease (IBD) regimen is limited. The current study examines the collective impact of barriers to adherence and anxiety/depressive symptoms on adolescent adherence to the IBD regimen. Methods Adolescents (n = 79) completed measures of barriers to adherence, adherence, and anxiety/depressive symptoms at one of two specialty pediatric IBD clinics. Results Most adolescents reported barriers to adherence and 1 in 8 reported borderline or clinically elevated levels of anxiety/depressive symptoms. Anxiety/depressive symptoms moderated the relationship between barriers to adherence and adherence. Post hoc probing revealed a significant, additive effect of higher anxiety/depressive symptoms in the barriers–adherence relationship, with adherence significantly lower among adolescents with higher barriers and higher anxiety/depressive symptoms. Conclusions In order to optimize adherence in adolescents, interventions should target not only barriers to adherence but also any anxiety/depressive symptoms that may negatively impact efforts to adhere to recommended treatment. PMID:22080456

  10. On the electrical conductivity of Ti-implanted alumina

    SciTech Connect

    Salvadori, M. C.; Teixeira, F. S.; Cattani, M.; Nikolaev, A.; Savkin, K. P.; Oks, E. M.; Park, H.-K.; Phillips, L.; Yu, K. M.; Brown, I. G.

    2012-03-15

    Ion implantation of metal species into insulators provides a tool for the formation of thin, electrically conducting, surface layers with experimenter-controlled resistivity. High energy implantation of Pt and Ti into alumina accelerator components has been successfully employed to control high voltage surface breakdown in a number of cases. In the work described here we have carried out some basic investigations related to the origin of this phenomenon. By comparison of the results of alumina implanted with Ti at 75 keV with the results of prior investigations of polymers implanted with Pt at 49 eV and Au at 67 eV, we describe a physical model of the effect based on percolation theory and estimate the percolation parameters for the Ti-alumina composite. We estimate that the percolation dose threshold is about 4 x 10{sup 16} cm{sup -2} and the maximum dose for which the system remains an insulator-conductor composite is about 10 x 10{sup 16} cm{sup -2}. The saturation electrical conductivity is estimated to be about 50 S/m. We conclude that the observed electrical conductivity properties of Ti-implanted alumina can be satisfactorily described by percolation theory.

  11. Silicon carbide particle size effects in alumina-based nanocomposites

    SciTech Connect

    Carroll, L.; Sternitzke, M.; Derby, B.

    1996-11-01

    Al{sub 2}O{sub 3}/SiC nanocomposites with a systematic variation in their SiC particle size together with monolithic alumina were produced using conventional powder processing, polymer pyrolysis and hot-pressing. The microstructures of the materials were investigated by means of transmission and scanning electron microscopy and correlated to their mechanical properties. All nanocomposites showed a clear increase in strength over similar grain size alumina but no clear dependence on the size of the SiC nano-reinforcement. However, the fracture toughness of the nanocomposites seems to increase with the SiC particle size but with values little changed from the toughness of monolithic alumina as measured by the Vickers indentation technique. The surface and bulk flaw populations were characterized using a Hertzian indentation technique and a Griffith flaw size analysis of strength data. The investigations revealed a significant difference between the monolithic alumina and nanocomposites. The strength increase in the nanocomposites is explained by the observed decrease in both the surface and processing flaw sizes, which further decreased with decreasing SiC particle size.

  12. Alumina-encapsulated vaccine formulation with improved thermostability and immunogenicity.

    PubMed

    Zhou, Hangyu; Wang, Guangchuan; Li, Xiao-Feng; Li, Yaling; Zhu, Shun-Ya; Qin, Cheng-Feng; Tang, Ruikang

    2016-05-11

    Developing vaccine formulations with excellent thermostability and immunogenicity remains a great challenge. By in situ encapsulating a live-attenuated strain of human enterovirus 71 (EV71) in alumina, we obtained a robust vaccine formulation named EV71@NanoAlum, which features significantly enhanced thermostability and immunogenicity. This attempt follows a material-based tactic for vaccine improvement. PMID:27098047

  13. Viscosity of alumina nanoparticles dispersed in car engine coolant

    SciTech Connect

    Kole, Madhusree; Dey, T.K.

    2010-09-15

    The present paper, describes our experimental results on the viscosity of the nanofluid prepared by dispersing alumina nanoparticles (<50 nm) in commercial car coolant. The nanofluid prepared with calculated amount of oleic acid (surfactant) was tested to be stable for more than 80 days. The viscosity of the nanofluids is measured both as a function of alumina volume fraction and temperature between 10 and 50 C. While the pure base fluid display Newtonian behavior over the measured temperature, it transforms to a non-Newtonian fluid with addition of a small amount of alumina nanoparticles. Our results show that viscosity of the nanofluid increases with increasing nanoparticle concentration and decreases with increase in temperature. Most of the frequently used classical models severely under predict the measured viscosity. Volume fraction dependence of the nanofluid viscosity, however, is predicted fairly well on the basis of a recently reported theoretical model for nanofluids that takes into account the effect of Brownian motion of nanoparticles in the nanofluid. The temperature dependence of the viscosity of engine coolant based alumina nanofluids obeys the empirical correlation of the type: log ({mu}{sub nf}) = A exp(BT), proposed earlier by Namburu et al. (author)

  14. Structure factor changes in supercooled yttria-alumina

    SciTech Connect

    Wilding, Martin C.; Greaves, G. Neville; Quang Vu Van; Majerus, Odile; Hennet, Louis

    2009-01-29

    Changes in the structure factor of yttria-alumina liquids have been identified in the supercooled range. Different inter-polyhedral configurations between AlO{sub 4} and YO{sub 6} groups distinguish low density and high density liquid phases. The coexistence of phases at high temperatures have been identified in simultaneous measurements of small angle x-ray scattering.

  15. Synthesis and textural evolution of alumina particles with mesoporous structures

    SciTech Connect

    Liu Xun; Peng Tianyou; Yao Jinchun; Lv Hongjin; Huang Cheng

    2010-06-15

    Alumina particles with mesostructures were synthesized through a chemical precipitation method by using different inorganic aluminum salts followed by a heterogeneous azeotropic distillation and calcination process. The obtained mesoporous {gamma}-alumina particles were systematically characterized by the X-ray diffraction, transmission electron microscopy and nitrogen adsorption-desorption measurement. Effects of the aluminum salt counter anion, pH value and the azeotropic distillation process on the structural or textural evolution of alumina particles were investigated. It is found that Cl{sup -} in the reaction solution can restrain the textural evolution of the resultant precipitates into two-dimensional crystallized pseudoboehmite lamellae during the heterogeneous azeotropic distillation, and then transformed into {gamma}-Al{sub 2}O{sub 3} particles with mesostructures after further calcination at 1173 K, whereas coexisting SO{sub 4}{sup 2-} can promote above morphology evolution and then transformed into {gamma}-Al{sub 2}O{sub 3} nanofibers after calcination at 1173 K. Moreover nearly all materials retain relatively high specific surface areas larger than 100 m{sup 2} g{sup -1} even after calcinations at 1173 K. - Graphical abstract: Co-existing Cl{sup -} is beneficial for the formation of {gamma}-alumina nanoparticles with mesostructures during the precipitation process. Interparticle and intraparticle mesopores can be derived from acidic solution and near neutral solution, respectively.

  16. Controlled growth of single nanowires within a supported alumina template

    NASA Astrophysics Data System (ADS)

    Vlad, A.; Mátéfi-Tempfli, M.; Faniel, S.; Bayot, V.; Melinte, S.; Piraux, L.; Mátéfi-Tempfli, S.

    2006-10-01

    A simple technique for fabricating single nanowires with well-defined position is presented. The process implies the use of a silicon nitride mask for selective electrochemical growth of the nanowires in a porous alumina template. We show that this method allows the realization of complex nanowire patterns as well as arrays of single nanowires with a precise position and spacing.

  17. Formation of {gamma}-alumina nanorods in presence of alanine

    SciTech Connect

    Dabbagh, Hossein A.; Rasti, Elham; Yalfani, Mohammad S.; Medina, Francesc

    2011-02-15

    Graphical abstract: Nanorod aluminas with a possible hexagonal symmetry, high surface area and relatively narrow pore size distribution were obtained. Research highlights: {yields} Research highlights {yields} Boehmite was prepared using a green sol-gel process in the presence of alanine. {yields} Nanorod aluminas with a high surface area were obtained. {yields} Addition of alanine would shape the size of the holes and crevices. {yields} The morphologies of the nanorods were revealed by transmission electron microscope. -- Abstract: Boehmite and alumina nanostructures were prepared using a simple green sol-gel process in the presence of alanine in water medium at room temperature. The uncalcined (dried at 200 {sup o}C) and the calcined materials (at 500, 600 and 700 {sup o}C for 4 h) were characterized using XRD, TEM, SEM, N{sub 2} physisorption and TGA. Nanorod aluminas with a possible hexagonal symmetry, high surface area and relatively narrow pore size distribution were obtained. The surface area was enhanced and crystallization was retarded as the alanine content increased. The morphologies of the nanoparticles and nanorods were revealed by a transmission electron microscope (TEM).

  18. Alumina contribution to CO oxidation: A TPR and IR study

    NASA Astrophysics Data System (ADS)

    Ammendola, P.; Barbato, P. S.; Lisi, L.; Ruoppolo, G.; Russo, G.

    2011-10-01

    The alumina contribution to CO oxidation in the absence of O2 on metal oxide supported catalysts was investigated by CO TPR and in-situ FTIR and DRIFT studies up to 800 °C. These tests were performed on two Al2O3 supported catalysts (1 wt.% Pt/La/γ-Al2O3 and 8 wt.% Cu/γ-Al2O3) and on two corresponding alumina supports (5 wt.% La2O3 stabilised γ-Al2O3 and high mechanical resistant spherical γ-Al2O3 particles). The quantitative determination of CO consumption and CO2 and H2 formation on the alumina supports was in agreement with a WGS reaction occurring between surface OH and CO with a predominantly 2:1 stoichiometry. In the CO TPR of metal oxide supported catalysts, in addition to the reduction of the metal, a WGS reaction took place with enhanced kinetics. This enhancement was the result of a CO spillover phenomenon from the metal to alumina hydroxyls. This phenomenon significantly affected the evaluation of the reduction degree of the supported metal and could not be neglected in the subsequent calculations.

  19. Preparation and characterization of supported alumina membranes for gas separation

    SciTech Connect

    Ting-Chia Huang; Huey-Ing Chen

    1994-12-31

    The preparation and characterization of gas-separative alumina membranes have been studied in this work. The boehmite sol and the porous support were prepared separately, and the supported membrane was obtained by dipping procedure. For the preparation of boehmite sols by sol-gel process, the parameters including water/alkoxide ratio, acid/alkoxide ratio, alcohol amount, hydrolysis temperature, and calcination condition were investigated. For the fabrication of alumina supports, the influence of PVA on the microstructure of the support was studied. The permeation of H{sub 2}, He, CH{sub 4}, N{sub 2}, O{sub 2} and CO{sub 2} through the supported membranes was also studied. The experimental results indicated that acid/alkoxide ratio and calcination temperature play important roles on controlling the size of boehmite sol, and the surface area and pore size of the {gamma}-alumina membrane. The amount of PVA can control the porosity of a support but not change the microstructural property significantly. The permeation results showed that the transport mechanism was primarily described by Knudsen diffusion. Consequently the estimated ideal separation factors for several mixtures were limited by the ratios of molecular weights of gases. The preparation parameters, microstructure, and gas permeation properties of supported alumina membranes have been related rudimentarily. It will be helpful for the forecoming work on the modification of membranes.

  20. Effects of nanoporous alumina on inflammatory cell response.

    PubMed

    Pujari, Shiuli; Hoess, Andreas; Shen, Jinhui; Thormann, Annika; Heilmann, Andreas; Tang, Liping; Karlsson-Ott, Marjam

    2014-11-01

    The present study focuses on the effects of nanoscale porosity on inflammatory response in vitro and in vivo. Nanoporous alumina membranes with different pore sizes, 20 and 200 nm in diameter, were used. We first evaluated cell/alumina interactions in vitro by observing adhesion, proliferation, and activation of a murine fibroblast and a macrophage cell line. To investigate the chronic inflammatory response, the membranes were implanted subcutaneously in mice for 2 weeks. Cell recruitment to the site of implantation was determined by histology and the production of cytokines was measured by protein array analysis. Both in vitro and in vivo studies showed that 200 nm pores induced a stronger inflammatory response as compared to the alumina with 20 nm pores. This was observed by an increase in macrophage activation in vitro as well as higher cell recruitment and generation of proinflammatory cytokines around the alumina with 200 nm pores, in vivo. Our results suggest that nanofeatures can be modulated in order to control the inflammatory response to implants. PMID:24288233

  1. Chromium oxide coatings improve thermal emissivity of alumina

    NASA Technical Reports Server (NTRS)

    Upshaw, V.

    1966-01-01

    Chromium oxide coatings improve thermal radiation characteristics of alumina-coated heater-cathode systems in vacuum tubes. Chromium oxide is applied either as a surface layer or as a doping material. The new coatings eliminate the high temperature migration problems of carbon surface treatments.

  2. Nanocomposite formed by titanium ion implantation into alumina

    SciTech Connect

    Spirin, R. E.; Salvadori, M. C. Teixeira, F. S.; Sgubin, L. G.; Cattani, M.; Brown, I. G.

    2014-11-14

    Composites of titanium nanoparticles in alumina were formed by ion implantation of titanium into alumina, and the surface electrical conductivity measured in situ as the implantation proceeded, thus generating curves of sheet conductivity as a function of dose. The implanted titanium self-conglomerates into nanoparticles, and the spatial dimensions of the buried nanocomposite layer can thus be estimated from the implantation depth profile. Rutherford backscattering spectrometry was performed to measure the implantation depth profile, and was in good agreement with the calculated profile. Transmission electron microscopy of the titanium-implanted alumina was used for direct visualization of the nanoparticles formed. The measured conductivity of the buried layer is explained by percolation theory. We determine that the saturation dose, φ{sub 0}, the maximum implantation dose for which the nanocomposite material still remains a composite, is φ{sub 0} = 2.2 × 10{sup 16 }cm{sup −2}, and the corresponding saturation conductivity is σ{sub 0} = 480 S/m. The percolation dose φ{sub c}, below which the nanocomposite still has basically the conductivity of the alumina matrix, was found to be φ{sub c} = 0.84 × 10{sup 16 }cm{sup −2}. The experimental results are discussed and compared with a percolation theory model.

  3. Development of an imaging system for the detection of alumina on turbine blades

    NASA Astrophysics Data System (ADS)

    Greenwell, S. J.; Kell, J.; Day, J. C. C.

    2014-03-01

    An imaging system capable of detecting alumina on turbine blades by acquiring LED-induced fluorescence images has been developed. Acquiring fluorescence images at adjacent spectral bands allows the system to distinguish alumina from fluorescent surface contaminants. Repair and overhaul processes require that alumina is entirely removed from the blades by grit blasting and chemical stripping. The capability of the system to detect alumina has been investigated with two series of turbine blades provided by Rolls-Royce plc. The results illustrate that the system provides a superior inspection method to visual assessment when ascertaining whether alumina is present on turbine blades during repair and overhaul processes.

  4. Effectiveness of specific intervention on treatment adherence of persons with mental illness: A pilot study

    PubMed Central

    Ahmed, Nurnahar; Gandhi, Sailaxmi; Baruah, Arunjyoti

    2015-01-01

    Context: Treatment nonadherence is one of the major obstacles in recovery even with the availability of a broad range of pharmacological and psychosocial treatments for persons with mental illnesses. Aims: The aim was to evaluate the effectiveness of specific interventions in improvement of treatment adherence of persons with mental illnesses. Settings and Design: A quasi-experimental study was conducted at a tertiary mental health care setting in North-east India. Materials and Methods: Total 30 numbers of patients were selected randomly for the study. Treatment adherence was assessed using the Medication Adherence Rating Scale and a structured Treatment Adherence Checklist. Data were collected before and 1-month after the specific interventions to the patients and their family members. Results: Result showed a significant improvement in the treatment adherence as verbalized by the patient (paired t = 3.973, P = 0.00, df = 29) as well as reported by the family members (paired t = 2.94, P = 0.00, df = 29) following the specific intervention. Conclusion: The study result suggested that specific intervention may be used for a better outcome of treatment for mental illnesses. The findings might be generalized following implementation of the intervention to a larger sample. PMID:26816430

  5. Predictive Validity of A Medication Adherence Measure in an Outpatient Setting

    PubMed Central

    Morisky, Donald E.; Ang, Alfonso; Krousel-Wood, Marie; Ward, Harry J.

    2008-01-01

    This study examines the psychometric properties and tests the concurrent and predictive validity of a structured, self-reported medication adherence measure in patients with hypertension. We also assessed various psychosocial determinants of adherence, such as knowledge, social support, satisfaction with care and complexity of the medical regimen. A total of 1367 patients participated in the study; mean age was 52.5 years, 40.8% were male, 76.5% were black, 51% graduated from high school, 26% were married, and 54.1% had income <$5,000. The eight-item medication adherence scale was reliable (α= 0.83) and significantly associated with blood pressure control (P<0.05). Using a cutpoint of less than 6, the sensitivity of the measure for identifying low versus higher adherers was estimated to be 93%, and the specificity was 53%. The medication adherence measure proved to be reliable with good concurrent and predictive validity in primarily low income, minority patients with hypertension, and might function as a screening tool in outpatient settings with other patient groups. PMID:18453793

  6. Direct visualization of the hydration layer on alumina nanoparticles with the fluid cell STEM in situ

    DOE PAGESBeta

    Firlar, Emre; Çınar, Simge; Kashyap, Sanjay; Akinc, Mufit; Prozorov, Tanya

    2015-05-21

    Rheological behavior of aqueous suspensions containing nanometer-sized powders is of relevance to many branches of industry. Unusually high viscosities observed for suspensions of nanoparticles compared to those of micron size powders cannot be explained by current viscosity models. Formation of so-called hydration layer on alumina nanoparticles in water was hypothesized, but never observed experimentally. We report here on the direct visualization of aqueous suspensions of alumina with the fluid cell in situ. We observe the hydration layer formed over the particle aggregates and show that such hydrated aggregates constitute new particle assemblies and affect the flow behavior of the suspensions.more » We discuss how these hydrated nanoclusters alter the effective solid content and the viscosity of nanostructured suspensions. As a result, our findings elucidate the source of high viscosity observed for nanoparticle suspensions and are of direct relevance to many industrial sectors including materials, food, cosmetics, pharmaceutical among others employing colloidal slurries with nanometer-scale particles.« less

  7. Effect of a clinic-wide social marketing campaign to improve adherence to antiretroviral therapy for HIV infection.

    PubMed

    Giordano, Thomas P; Rodriguez, Sonia; Zhang, Hong; Kallen, Michael A; Jibaja-Weiss, Maria; Buscher, April L; Arya, Monisha; Suarez-Almazor, Maria E; Ross, Michael

    2013-01-01

    This demonstration study tested the impact of a 5-month clinic-wide social marketing campaign at improving adherence to antiretroviral therapy (ART). The intervention included a video, posters, pens, mugs, and lapel buttons with the campaign slogan "Live the Solution: Take Your Pills Every Day." Participants self-reported adherence over a 4-week interval, the primary outcome, with a visual analogue scale. Pre- and post-intervention surveys were completed by 141 participants. Adherence did not change over time (absolute mean change -2.02 %, paired t test P = 0.39). Among the 39.7 % of participants who correctly identified the campaign slogan on the post-intervention survey, adherence increased by 3.3 %, while it decreased in the other participants by 5.5 % (paired t test P = 0.07). The well-received campaign did not increase short-term adherence to ART, but adherence tended to increase in participants who were more engaged with the intervention. Future interventions should engage patients more completely and have a more potent effect on adherence. PMID:22983536

  8. Free HIV Antiretroviral Therapy Enhances Adherence among Individuals on Stable Treatment: Implications for Potential Shortfalls in Free Antiretroviral Therapy

    PubMed Central

    Byakika-Tusiime, Jayne; Polley, Eric C.; Oyugi, Jessica H.; Bangsberg, David R.

    2013-01-01

    Objective To estimate the population-level causal effect of source of payment for HIV medication on treatment adherence using Marginal Structural Models. Methods Data were obtained from an observational cohort of 76 HIV-infected individuals with at least 24 weeks of antiretroviral therapy treatment from 2002 to 2007 in Kampala, Uganda. Adherence was the primary outcome and it was measured using the 30-day visual analogue scale. Marginal structural models (MSM) were used to estimate the effect of source of payment for HIV medication on adherence, adjusting for confounding by income, duration on antiretroviral therapy (ART), timing of visit, prior adherence, prior CD4+ T cell count and prior plasma HIV RNA. Traditional association models were also examined and the results compared. Results Free HIV treatment was associated with a 3.8% improvement in adherence in the marginal structural model, while the traditional statistical models showed a 3.1–3.3% improvement in adherence associated with free HIV treatment. Conclusion Removing a financial barrier to treatment with ART by providing free HIV treatment appears to significantly improve adherence to antiretroviral therapy. With sufficient information on confounders, MSMs can be used to make robust inferences about causal effects in epidemiologic research. PMID:24039704

  9. Overactive bladder: strategies to ensure treatment compliance and adherence

    PubMed Central

    Dhaliwal, Prabhpreet; Wagg, Adrian

    2016-01-01

    Overactive bladder is a common, debilitating condition for many patients who may benefit from pharmacological management of their condition. However, adherence to medication in this condition is markedly worse than other chronic medical conditions. This review explores what is known about persistence and the factors which influence medication adherence for overactive bladder, those factors that might be modifiable to improve adherence, and the measures the health care provider can take to optimize adherence to therapy and thereby improve treatment outcomes. PMID:27350744

  10. Improved assay for quantitating adherence of ruminal bacteria to cellulose.

    PubMed Central

    Rasmussen, M A; White, B A; Hespell, R B

    1989-01-01

    A quantitative technique suitable for the determination of adherence of ruminal bacteria to cellulose was developed. This technique employs adherence of cells to cellulose disks and alleviates the problem of nonspecific cell entrapment within cellulose particles. By using this technique, it was demonstrated that the adherence of Ruminococcus flavefaciens FD1 to cellulose was inhibited by formaldehyde, methylcellulose, and carboxymethyl cellulose. Adherence was unaffected by acid hydrolysates of methylcellulose, glucose, and cellobiose. PMID:2782879

  11. Influence of Alumina Additions on the Physical and Chemical Properties of Lithium-iron-phosphate Glasses

    NASA Astrophysics Data System (ADS)

    Liu, Huali; Yang, Ruijuan; Wang, Yinghui; Liu, Shiquan

    Alumina improves the properties and depresses the devitrification of soda-lime-silicate glasses. Herein, the influence of alumina on the glass transition temperature, density, chemical durability, crystallization of lithium-iron-phosphate (LIP) glass has been investigated. As alumina was added to replace the iron oxide in a base LIP glass with the molar composition of Li2O:Fe2O3:P2O5=30:20:50, the alumina-containing glasses have increased Tg, densities and chemical stabilities than the base glass. When the amount of alumina is increased from 2 to 6 mol, the Tg value slightly increases, whereas the density decreases. However, the smallest weight loss is shown for the glass containing 3.2 mol of alumina. The variations of the properties with alumina are explained based on the infrared structure analysis results. In addition, it is found the either the base or the alumina-containing glasses have surface crystallization upon heat-treatments. Under the same treatment conditions, the base glass exhibits a thin layer of crystallization with LiFeP2O7 as the main phase. In contrast, alumina-containing glasses show much higher degree of crystallization, which is further increased with the amount of alumina. This trend is opposite to that of silicate glass. Besides the LiFeP2O7 main phase, Fe7(PO4) phase is also identified in the crystallized alumina-containing glasses.

  12. Medication Adherence in Psychopharmacologically Treated Adults with ADHD

    ERIC Educational Resources Information Center

    Safren, Steven A.; Duran, Petra; Yovel, Iftah; Perlman, Carol A.; Sprich, Susan

    2007-01-01

    Objective: One of the potential causes of residual symptoms of ADHD in adults can be difficulties with consistent adherence to medications. Method: This formative study examined self-reported medication adherence in adults with ADHD with clinically significant symptoms despite medication treatment. Results: Mean adherence for the two-week period…

  13. A Matter of Trust: Patient Barriers to Primary Medication Adherence

    ERIC Educational Resources Information Center

    Polinski, J. M.; Kesselheim, A. S.; Frolkis, J. P.; Wescott, P.; Allen-Coleman, C.; Fischer, M. A.

    2014-01-01

    Primary medication adherence occurs when a patient properly fills the first prescription for a new medication. Primary adherence only occurs about three-quarters of the time for antihypertensive medications. We assessed patients' barriers to primary adherence and attributes of patient-provider discussions that might improve primary adherence…

  14. Adherence indicators predict changes in health outcomes: HUB City Steps

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Participant adherence is a major threat to intervention effectiveness. Most researchers have reported effects of a single adherence measure on health outcomes. The objective of this analysis was to evaluate two adherence measures, separately and in combination, for predicting changes in health out...

  15. Analyzing Adherence to Prenatal Supplement: Does Pill Count Measure Up?

    PubMed Central

    Appelgren, Kristie E.; Nietert, Paul J.; Hulsey, Thomas C.; Hollis, Bruce W.; Wagner, Carol L.

    2010-01-01

    Objective. To determine if adherence as measured by pill count would show a significant association with serum-based measures of adherence. Methods. Data were obtained from a prenatal vitamin D supplementation trial where subjects were stratified by race and randomized into three dosing groups: 400 (control), 2000, or 4000 IU vitamin D3/day. One measurement of adherence was obtained via pill counts remaining compared to a novel definition for adherence using serum 25-hydroxy-vitamin D (25-OH-D) levels (absolute change in 25(OH)D over the study period and the subject's steady-state variation in their 25(OH)D levels). A multivariate logistic regression model examined whether mean percent adherence by pill count was significantly associated with the adherence measure by serum metabolite levels. Results. Subjects' mean percentage of adherence by pill count was not a significant predictor of adherence by serum metabolite levels. This finding was robust across a series of sensitivity analyses. Conclusions. Based on our novel definition of adherence, pill count was not a reliable predictor of adherence to protocol, and calls into question how adherence is measured in clinical research. Our findings have implications regarding the determination of efficacy of medications under study and offer an alternative approach to measuring adherence of long half-life supplements/medications. PMID:20169132

  16. Advanced morphological analysis of patterns of thin anodic porous alumina

    SciTech Connect

    Toccafondi, C.; Stępniowski, W.J.; Leoncini, M.; Salerno, M.

    2014-08-15

    Different conditions of fabrication of thin anodic porous alumina on glass substrates have been explored, obtaining two sets of samples with varying pore density and porosity, respectively. The patterns of pores have been imaged by high resolution scanning electron microscopy and analyzed by innovative methods. The regularity ratio has been extracted from radial profiles of the fast Fourier transforms of the images. Additionally, the Minkowski measures have been calculated. It was first observed that the regularity ratio averaged across all directions is properly corrected by the coefficient previously determined in the literature. Furthermore, the angularly averaged regularity ratio for the thin porous alumina made during short single-step anodizations is lower than that of hexagonal patterns of pores as for thick porous alumina from aluminum electropolishing and two-step anodization. Therefore, the regularity ratio represents a reliable measure of pattern order. At the same time, the lower angular spread of the regularity ratio shows that disordered porous alumina is more isotropic. Within each set, when changing either pore density or porosity, both regularity and isotropy remain rather constant, showing consistent fabrication quality of the experimental patterns. Minor deviations are tentatively discussed with the aid of the Minkowski measures, and the slight decrease in both regularity and isotropy for the final data-points of the porosity set is ascribed to excess pore opening and consequent pore merging. - Highlights: • Thin porous alumina is partly self-ordered and pattern analysis is required. • Regularity ratio is often misused: we fix the averaging and consider its spread. • We also apply the mathematical tool of Minkowski measures, new in this field. • Regularity ratio shows pattern isotropy and Minkowski helps in assessment. • General agreement with perfect artificial patterns confirms the good manufacturing.

  17. Thin porous alumina sheets as supports for stabilizing gold nanoparticles.

    PubMed

    Wang, Jie; Lu, An-Hui; Li, Mingrun; Zhang, Weiping; Chen, Yong-Sheng; Tian, Dong-Xu; Li, Wen-Cui

    2013-06-25

    Thin porous alumina sheets have been synthesized using a lysine-assisted hydrothermal approach resulting in an extraordinary catalyst support that can stabilize Au nanoparticles at annealing temperatures up to 900 °C. Remarkably, the unique architecture of such an alumina with thin sheets (average thickness ~15 nm and length 680 nm) and rough surface is beneficial to prevent gold nanoparticles from sintering. HRTEM observations clearly showed that the epitaxial growth between Au nanoparticles and alumina support was due to strong interfacial interactions, further explaining the high sinter-stability of the obtained Au/Al2O3 catalyst. Consequently, despite calcination at 700 °C, the catalyst maintains its gold nanoparticles of size predominantly 2 ± 0.8 nm. Surprisingly, catalyst annealed at 900 °C retained the highly dispersed small gold nanoparticles. It was also observed that a few gold particles (6-25 nm) were encapsulated by an alumina layer (thickness less than 1 nm) to minimize the surface energy, revealing a surface restructuring of the gold/support interface. As a typical and size-dependent reaction, CO oxidation is used to evaluate the performance of Au/Al2O3 catalysts. The results obtained demonstrated Au/Al2O3 catalyst calcined at 700 °C exhibited excellent activity with a complete CO conversion at ∼30 °C (T100% = 30 °C), and even after calcination at 900 °C, the catalyst still achieved its T50% at 158 °C. In sharp contrast, Au catalyst prepared using conventional alumina support shows almost no activity under the same preparation and catalytic test conditions. PMID:23682983

  18. Synthesis and structural evaluation of freeze-cast porous alumina

    SciTech Connect

    Souza, Douglas F.; Nunes, Eduardo H.M.; Pimenta, Daiana S.; Vasconcelos, Daniela C.L.; Nascimento, Jailton F.; Grava, Wilson; Vasconcelos, Wander L.

    2014-10-15

    In this work we fabricated alumina samples by the freeze-casting technique using tert-butanol as the solvent. The prepared materials were examined by scanning electron microscopy and X-ray microtomography. Next, they were coated with sol–gel silica films by dip-coating. Permeability tests were carried out in order to assess the permeation behavior of the materials processed in this study. We observed that the sintering time and alumina loading showed a remarkable effect on both the structural properties and flexural strength of the freeze-cast samples. Nitrogen adsorption tests revealed that the silica prepared in this study exhibited a microporous structure. It was observed that the presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance by about one order of magnitude. Because of the similar kinetic diameters of nitrogen and carbon dioxide, the CO{sub 2}/N{sub 2} system showed a separation efficiency that was lower than that observed for the He/CO{sub 2} and He/N{sub 2} systems. We noticed that increasing the feed pressure improved the separation capacity of the obtained materials. - Highlights: • Porous alumina samples obtained by the freeze-casting technique • Microporous silica coating prepared by a simple sol–gel dip-coating methodology • Samples examined by SEM, μ-CT, and nitrogen sorption tests • Mechanical tests were carried out in the freeze-cast samples. • The presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance.

  19. Understanding how adherence goals promote adherence behaviours: a repeated measure observational study with HIV seropositive patients

    PubMed Central

    2012-01-01

    Background The extent to which patients follow treatments as prescribed is pivotal to treatment success. An exceptionally high level (> 95%) of HIV medication adherence is required to suppress viral replication and protect the immune system and a similarly high level (> 80%) of adherence has also been suggested in order to benefit from prescribed exercise programmes. However, in clinical practice, adherence to both often falls below the desirable level. This project aims to investigate a wide range of psychological and personality factors that may lead to adherence/non-adherence to medical treatment and exercise programmes. Methods HIV positive patients who are referred to the physiotherapist-led 10-week exercise programme as part of the standard care are continuously recruited. Data on social cognitive variables (attitude, intention, subjective norms, self-efficacy, and outcome beliefs) about the goal and specific behaviours, selected personality factors, perceived quality of life, physical activity, self-reported adherence and physical assessment are collected at baseline, at the end of the exercise programme and again 3 months later. The project incorporates objective measures of both exercise (attendance log and improvement in physical measures such as improved fitness level, weight loss, improved circumferential anthropometric measures) and medication adherence (verified by non-invasive hair analysis). Discussion The novelty of this project comes from two key aspects, complemented with objective information on exercise and medication adherence. The project assesses beliefs about both the underlying goal such as following prescribed treatment; and about the specific behaviours such as undertaking the exercise or taking the medication, using both implicit and explicit assessments of patients’ beliefs and attitudes. We predict that i) the way people think about the underlying goal of their treatments explains medication and exercise behaviours over and above

  20. The reactive element effect of ceria particle dispersion on alumina growth: A model based on microstructural observations

    NASA Astrophysics Data System (ADS)

    Wang, X.; Peng, X.; Tan, X.; Wang, F.

    2016-07-01

    The oxidation kinetics of alumina-forming metals can be affected by adding a small amount of a reactive (normally rare earth) element oxide (RExOy) and the segregation of the reactive element (RE) ions to the growing alumina grain boundaries (GBs) has been considered as a responsible reason. However, this interpretation remains a controversial issue as to how RE ions are produced by RExOy which is thermodynamically and chemically stable in metals. The question is answered by a model that is based on transmission electron microscopy (TEM) investigation of a CeO2-dispersed nickel aluminide oxidized in air at 1100 °C. The CeO2 dispersion is incorporated into the alumina scale by the inward growth of inner α-Al2O3, where it partially dissolves producing tetravalent Ce cations which then transform to trivalent cations by trapping electrons. The trivalent cations segregate to the α-Al2O3 GBs and diffuse outward along first the GBs and later the twin boundaries (TBs) in the outer γ-Al2O3 layer, being precipitated as Ce2O3 particles near surface.

  1. The reactive element effect of ceria particle dispersion on alumina growth: A model based on microstructural observations.

    PubMed

    Wang, X; Peng, X; Tan, X; Wang, F

    2016-01-01

    The oxidation kinetics of alumina-forming metals can be affected by adding a small amount of a reactive (normally rare earth) element oxide (RExOy) and the segregation of the reactive element (RE) ions to the growing alumina grain boundaries (GBs) has been considered as a responsible reason. However, this interpretation remains a controversial issue as to how RE ions are produced by RExOy which is thermodynamically and chemically stable in metals. The question is answered by a model that is based on transmission electron microscopy (TEM) investigation of a CeO2-dispersed nickel aluminide oxidized in air at 1100 °C. The CeO2 dispersion is incorporated into the alumina scale by the inward growth of inner α-Al2O3, where it partially dissolves producing tetravalent Ce cations which then transform to trivalent cations by trapping electrons. The trivalent cations segregate to the α-Al2O3 GBs and diffuse outward along first the GBs and later the twin boundaries (TBs) in the outer γ-Al2O3 layer, being precipitated as Ce2O3 particles near surface. PMID:27406938

  2. The reactive element effect of ceria particle dispersion on alumina growth: A model based on microstructural observations

    PubMed Central

    Wang, X.; Peng, X.; Tan, X.; Wang, F.

    2016-01-01

    The oxidation kinetics of alumina-forming metals can be affected by adding a small amount of a reactive (normally rare earth) element oxide (RExOy) and the segregation of the reactive element (RE) ions to the growing alumina grain boundaries (GBs) has been considered as a responsible reason. However, this interpretation remains a controversial issue as to how RE ions are produced by RExOy which is thermodynamically and chemically stable in metals. The question is answered by a model that is based on transmission electron microscopy (TEM) investigation of a CeO2-dispersed nickel aluminide oxidized in air at 1100 °C. The CeO2 dispersion is incorporated into the alumina scale by the inward growth of inner α-Al2O3, where it partially dissolves producing tetravalent Ce cations which then transform to trivalent cations by trapping electrons. The trivalent cations segregate to the α-Al2O3 GBs and diffuse outward along first the GBs and later the twin boundaries (TBs) in the outer γ-Al2O3 layer, being precipitated as Ce2O3 particles near surface. PMID:27406938

  3. Interactions of dispersants and binders with {alpha}-alumina in aqueous suspensions

    SciTech Connect

    Hidber, P.; Graule, T.; Gauckler, L.

    1995-12-31

    Citric acid and poly(vinyl alcohol) (PVA) are commonly used as dispersant and binder for aqueous alumina slurries. The interaction of citric acid and PVA with the alumina surface as well as the competitive reaction of these two additives on the alumina surface have been studied by measurements of the adsorption density and electrophoretic mobility. By variation of the citric acid concentration, it is possible to adjust the isoelectric point (IEP) of alumina to any pH-value between 9 and 3. For citric acid, a high adsorption density on alumina was measured over a broad pH range, whereas the adsorption of PVA is very low. The adsorption density of citric acid on alumina is not influenced by the presence of PVA, whereas the polymer is displaced by citric acid from the alumina surface. Enhanced binder migration in wet green bodies during the drying process is a consequence of this displacement.

  4. High alumina metamorphic rocks of the Kings Mountain district, North Carolina and South Carolina

    USGS Publications Warehouse

    Potter, Donald Brandreth

    1954-01-01

    The following evidence suggests that high alumina quartzite in this district is of metasedimentary origin: high alumina quartzite occurs as well defined thin beds that can be traced up to three and one half miles along strike; many outcrops of high alumina quartzite exhibit compositional layering (i.e., kyanigte quartzite is interlayered with staurolite quartzite, and with non-kyanitic magnetiferous quartzite); high alumina quartzite beds occur in a conformable sequence of high alumina metasedimentary and metavolcanic schists. It is suggested that the high alumina quartzite beds are metamorphosed beds of sandy or silty clay; these beds probably represent one stage in the deposition of fine grained clayey clastic sediments. No evidence was found to support the view of Smith and Newcombe (1951) that the kyanite at Henry Knob developed by hudrothermal introduction of alumina. The present study indicates that kyanite in the kyanite quartzite here, as throughout the district, is of metasedimentary origin.

  5. Processing and Mechanical Properties of Various Zirconia/Alumina Composites for Fuel Cell Applications

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Bansal, Narottam P.

    2002-01-01

    Various electrolyte materials for solid oxide fuel cells were fabricated by hot pressing 10 mol% yttria-stabilized zirconia (10-YSZ) reinforced with two different forms of alumina, particulates and platelets, each containing 0 to 30 mol% alumina. Flexure strength and fracture toughness of both particulate and platelet composites at ambient temperature increased with increasing alumina content, reaching a maximum at 30 mot% alumina. For a given alumina content, strength of particulate composites was greater than that of platelet composites, whereas, the difference in fracture toughness between the two composite systems was negligible. No virtual difference in elastic modulus and density was observed for a given alumina content between particulate and platelet composites. Thermal cycling up to 10 cycles between 200 to 1000 C did not show any effect on strength degradation of the 30 mol% platelet composites, indicative of negligible influence of CTE mismatches between YSZ matrix and alumina grains.

  6. Synthesis of highly ordered mesoporous alumina thin films and their framework crystallization to γ-alumina phase.

    PubMed

    Jiang, Xiangfen; Oveisi, Hamid; Nemoto, Yoshihiro; Suzuki, Norihiro; Wu, Kevin C-W; Yamauchi, Yusuke

    2011-11-01

    Here we report the preparation of highly ordered mesoporous alumina films existing both as P6(3)/mmc and Fm-3m mesostructures by using triblock copolymer Pluronic P123 as the structure-directing agent. 2D grazing-incidence small-angle X-ray scattering (GI-SAXS) completely proves the existence of two different mesopore structures (i.e., [001]-oriented P6(3)/mmc and [111]-oriented Fm-3m symmetries). After calcination at 1000 °C, the amorphous alumina framework is successfully converted to γ-alumina crystals. During the crystallization process, large uniaxial shrinkage occurs along the direction perpendicular to the substrate with the retention of horizontal mesoscale periodicity, thereby resulting in formation of partially vertical mesoporosity in the film. Through detailed electron microscopic study, we discuss the formation mechanism for the vertical mesoporosity upon calcination. The obtained mesoporous γ-alumina film shows high thermal stability up to 1000 °C, which is highly useful in wide research areas such as catalyst supports and separators. PMID:21603720

  7. Ethical Questions in Medical Electronic Adherence Monitoring.

    PubMed

    Campbell, Jeffrey I; Eyal, Nir; Musiimenta, Angella; Haberer, Jessica E

    2016-03-01

    Electronic adherence monitors (EAMs) record and report an array of health behaviors, ranging from taking daily medications to wearing medical devices. EAMs are utilized in research worldwide and are being investigated for clinical use. However, there is also growing popular concern about the extent to which electronic devices may be used to monitor individuals, including allegations in the media that EAMs represent a move towards "Big Brother" in medicine. Here, we highlight the unique benefits as well as the potential ethical challenges that electronic adherence monitoring generates. These challenges surround autonomy, privacy and confidentiality, trust, and ancillary care obligations. We describe key questions within each of these domains that warrant further investigation, and present potential solutions to many of the concerns raised. PMID:26358284

  8. Subpopulations in purified platelets adhering on glass.

    PubMed

    Donati, Alessia; Gupta, Swati; Reviakine, Ilya

    2016-01-01

    Understanding how platelet activation is regulated is important in the context of cardiovascular disorders and their management with antiplatelet therapy. Recent evidence points to different platelet subpopulations performing different functions. In particular, procoagulant and aggregating subpopulations have been reported in the literature in platelets treated with the GPVI agonists. How the formation of platelet subpopulations upon activation is regulated remains unclear. Here, it is shown that procoagulant and aggregating platelet subpopulations arise spontaneously upon adhesion of purified platelets on clean glass surfaces. Calcium ionophore treatment of the adhering platelets resulted in one platelet population expressing both the procoagulant and the adherent population markers phosphatidylserine and the activated form of GPIIb/IIIa, while all of the platelets expressed CD62P independently of the ionophore treatment. Therefore, all platelets have the capacity to express all three activation markers. It is concluded that platelet subpopulations observed in various studies reflect the dynamics of the platelet activation process. PMID:27338300

  9. Aqueous-Phase Preparation of Model HDS Catalysts on Planar Alumina Substrates: Support Effect on Mo Adsorption and Sulfidation.

    PubMed

    Bara, Cédric; Plais, Lucie; Larmier, Kim; Devers, Elodie; Digne, Mathieu; Lamic-Humblot, Anne-Félicie; Pirngruber, Gerhard D; Carrier, Xavier

    2015-12-23

    The role of the oxide support on the structure of the MoS2 active phase (size, morphology, orientation, sulfidation ratio, etc.) remains an open question in hydrotreating catalysis and biomass processing with important industrial implications for the design of improved catalytic formulations. The present work builds on an aqueous-phase surface-science approach using four well-defined α-alumina single crystal surfaces (C (0001), A (112̅0), M (101̅0), and R (11̅02) planes) as surrogates for γ-alumina (the industrial support) in order to discriminate the specific role of individual support facets. The reactivity of the various surface orientations toward molybdenum adsorption is controlled by the speciation of surface hydroxyls that determines the surface charge at the oxide/water interface. The C (0001) plane is inert, and the R (11̅02) plane has a limited Mo adsorption capacity while the A (112̅0) and M (101̅0) surfaces are highly reactive. Sulfidation of model catalysts reveals the highest sulfidation degree for the A (112̅0) and M (101̅0) planes suggesting weak metal/support interactions. Conversely, a low sulfidation rate and shorter MoS2 slabs are found for the R (11̅02) plane implying stronger Mo-O-Al bonds. These limiting cases are reminiscent of type I/type II MoS2 nanostructures. Structural analogies between α- and γ- alumina surfaces allow us to bridge the material gap with real Al2O3-supported catalysts. Hence, it can be proposed that Mo distribution and sulfidation rate are heterogeneous and surface-dependent on industrial γ-Al2O3-supported high-surface-area catalysts. These results demonstrate that a proper control of the γ-alumina morphology is a strategic lever for a molecular-scale design of hydrotreating catalysts. PMID:26588441

  10. Medication adherence in patients with schizophrenia.

    PubMed

    Phan, Stephanie V

    2016-01-01

    Medication nonadherence is common among patients with schizophrenia and due to a variety of factors including lack of insight, psychopathology, substance use disorder, issues associated with treatment, stigma, fragmentation of care, cultural influences, and socioeconomic status. Among this population, nonadherence is problematic because it can lead to decompensation or exacerbation of symptoms, relapse, rehospitalization or greater use of emergency psychiatric services, functional decline, and increased risk of death. Psychoeducational approaches alone are ineffective, but in combination with behavioral interventions, appear to be effective. Involving the patient's support system, in addition to other interventions, can improve treatment adherence. Many medication-related factors, such as effectiveness and tolerability of antipsychotics, regimen complexity, and past medication trials impact appropriate medication use. Therefore, optimizing the patient's pharmacotherapeutic regimens can improve adherence. Additional factors favorably influencing adherence include involving the patient in their treatment, fostering a therapeutic alliance, implementing/using reminder systems, and addressing substance use disorder. Medication nonadherence arises from multiple reasons that vary between patients. Thus, the most effective strategies to improve adherence are multifactorial and may involve both psychoeducational and behavioral techniques, as well as previously listed approaches. Strategies should be targeted toward the patient and their support system, whenever possible, to further improve the chances of appropriate medication use. Recognizing that all patients with schizophrenia are at risk for medication nonadherence is important. No one technique has been shown to be most effective; therefore, the risk for nonadherence should continually be assessed and multiple strategies should be targeted to the patient (and caregiver) and repeatedly implemented throughout the course

  11. Adherence with drug therapy in the rheumatic diseases Part one: a review of adherence rates.

    PubMed

    Hill, Jackie

    2005-01-01

    Drug therapy plays a major role in the management of many rheumatic diseases and is particularly important in rheumatoid arthritis (RA) because of the significant rates of morbidity and mortality (Pincus, 1995). Understanding of the pathogenesis of RA has led to the development of new and more effective drugs (Emery et al., 1999), but the ultimate efficacy of any drug therapy depends upon the patient's decision to take it. There is widespread agreement that many people with rheumatic disease do not adhere to their medication regimens (Deyo et al., 1981; Belcon et al., 1984; Pullar et al., 1988; Hill et al., 2001). Research has demonstrated that 50% of women taking hormone replacement therapy for the prevention of osteoporosis discontinue treatment after a year (Fordham, 2000) and similar rates of discontinuation are found in other chronic diseases (Haynes et al., 1996, 2000). This is bewildering as, in asymptomatic illnesses such as hypertension and diabetes, the expectation is that levels of adherence would be lower than in diseases where pain and stiffness are present. The picture becomes even more confusing when we consider the findings from a recent multi-country study of RA, which found no association between adherence and disease severity, nor with the treatment prescribed (Viller et al., 1999). In chronic disease poor adherence is commonplace. The World Health Organization (WHO) recognizes this and has recently stated that 'poor adherence to treatment of chronic diseases is a worldwide problem of striking magnitude' and cites adherence to long-term therapy for chronic illnesses in developed countries averaging just 50% (WHO, 2003). The first part of this two part review focuses on adherence with drug therapy, and the second part discusses different methods of measuring it. PMID:17041995

  12. Adherent Raindrop Modeling, Detectionand Removal in Video.

    PubMed

    You, Shaodi; Tan, Robby T; Kawakami, Rei; Mukaigawa, Yasuhiro; Ikeuchi, Katsushi

    2016-09-01

    Raindrops adhered to a windscreen or window glass can significantly degrade the visibility of a scene. Modeling, detecting and removing raindrops will, therefore, benefit many computer vision applications, particularly outdoor surveillance systems and intelligent vehicle systems. In this paper, a method that automatically detects and removes adherent raindrops is introduced. The core idea is to exploit the local spatio-temporal derivatives of raindrops. To accomplish the idea, we first model adherent raindrops using law of physics, and detect raindrops based on these models in combination with motion and intensity temporal derivatives of the input video. Having detected the raindrops, we remove them and restore the images based on an analysis that some areas of raindrops completely occludes the scene, and some other areas occlude only partially. For partially occluding areas, we restore them by retrieving as much as possible information of the scene, namely, by solving a blending function on the detected partially occluding areas using the temporal intensity derivative. For completely occluding areas, we recover them by using a video completion technique. Experimental results using various real videos show the effectiveness of our method. PMID:26485475

  13. Motivational factors of adherence to cardiac rehabilitation

    PubMed Central

    Shahsavari, Hooman; Shahriari, Mohsen; Alimohammadi, Nasrollah

    2012-01-01

    Background: Main suggested theories about patients’ adherence to treatment regimens recognize the importance of motivation in positive changes in behaviors. Since cardiac diseases are chronic and common, cardiac rehabilitation as an effective prevention program is crucial in management of these diseases. There is always concern about the patients’ adherence to cardiac rehabilitation. The aim of this study was to describe the motivational factors affecting the patients’ participation and compliance to cardiac rehabilitation by recognizing and understanding the nature of patients’ experiences. Materials and Methods: The participants were selected among the patients with cardiac diseases who were referred to cardiac rehabilitation in Isfahan Cardiovascular Research Center, Iran. The purposive sampling method was used and data saturation achieved after 8 semi-structured interviews. Findings: The three main concepts obtained from this study are “beliefs”, “supporters” and “group cohesion”. Conclusions: In cardiac rehabilitation programs, emphasis on motivational factors affects the patient’s adherence. It is suggested that in cardiac rehabilitation programs more attention should be paid to patients’ beliefs, the role of patients’ supporters and the role of group-based rehabilitation. PMID:23833634

  14. Four therapeutic diets: adherence and acceptability.

    PubMed

    Berkow, Susan E; Barnard, Neal; Eckart, Jill; Katcher, Heather

    2010-01-01

    Many health conditions are treated, at least in part, by therapeutic diets. Although the success of any intervention depends on its acceptability to the patient, the acceptability of therapeutic diets and factors that influence it have been largely neglected in nutrition research. A working definition of acceptability is proposed and an examination and summary are provided of available data on the acceptability of common diet regimens used for medical conditions. The goal is to suggest ways to improve the success of therapeutic diets. The proposed working definition of "acceptability" refers to the user's judgment of the advantages and disadvantages of a therapeutic diet-in relation to palatability, costs, and effects on eating behaviour and health-that influence the likelihood of adherence. Very low-calorie, reduced-fat omnivorous, vegetarian and vegan, and low-carbohydrate diets all achieve acceptability among the majority of users in studies of up to one year, in terms of attrition and adherence rates and results of questionnaires assessing eating behaviours. Longer studies are fewer, but they suggest that vegetarian, vegan, and reduced-fat diets are acceptable, as indicated by sustained changes in nutrient intake. Few studies of this length have been published for very low-calorie or low-carbohydrate diets. Long-term studies of adherence and acceptability of these and other therapeutic diets are warranted. PMID:21144137

  15. [Adherence to chronic medication: also a frequent problem in Belgium!].

    PubMed

    Liekens, S; Hulshagen, L; Dethier, M; Laekeman, G; Foulon, V

    2013-12-01

    Medication adherence in chronic conditions such as asthma, type 2 diabetes, heart failure, HIV and cancer appears to be a frequent problem. However, the literature on adherence in patients who use inhaled corticosteroids (ICS), oral hypoglycemic agents, drugs for heart failure, antiretrovirals or oral chemotherapy, contains little or no relevant data for Belgium. In the context of a Master thesis in Pharmaceutical care at KU Leuven, a quantitative study was performed to determine the prevalence of adherence to chronic medication in Belgium. This retrospective, cross-sectional study used a database containing refill data of a regional pharmacists' association (KLAV). Out of the 603 pharmacies affiliated with this association, all 50 pharmacies where HIV medication was delivered, were selected. Dispensing data from the selected pharmacies were collected from 01/07/2008 to 31/12/2009 for five pathologies, i.e.; asthma, type 2 diabetes, heart failure, HIV and cancer. Adherence (TT) was calculated with the Medication Refill Adherence (MRA) method. In order to determine whether there were associations between age, gender, drug class and adherence, Chi-square tests were used. Compared with the other patients, cancer patients were the most adherent in taking their drugs (median adherence rate = 88%). In addition, this was the only group in which the median adherence rate was above the set limit of 80%. The patients who were prescribed inhaled corticosteroids were the least adherent (median adherence rate = 38%). More than 50% of patients with asthma/COPD, heart failure and diabetes were classified as "under-users". Furthermore, the results showed a significant association within asthma patients between gender and adherence. In asthma, type 2 diabetes, heart failure and HIV patients there was a significant relationship between age and adherence and drug class and adherence. As the current study has some limitations, the results should be handled with caution. Nevertheless

  16. A Randomized Controlled Trial of Personalized Text Message Reminders to Promote Medication Adherence Among HIV-Positive Adolescents and Young Adults.

    PubMed

    Garofalo, Robert; Kuhns, Lisa M; Hotton, Anna; Johnson, Amy; Muldoon, Abigail; Rice, Dion

    2016-05-01

    HIV-positive adolescents and young adults often experience suboptimal medication adherence, yet few interventions to improve adherence in this group have shown evidence of efficacy. We conducted a randomized trial of a two-way, personalized daily text messaging intervention to improve adherence to antiretroviral therapy (ART) among N = 105 poorly adherent HIV-positive adolescents and young adults, ages 16-29. Adherence to ART was assessed via self-reported visual analogue scale (VAS; 0-100 %) at 3 and 6-months for mean adherence level and proportion ≥90 % adherent. The average effect estimate over the 6-month intervention period was significant for ≥90 % adherence (OR = 2.12, 95 % CI 1.01-4.45, p < .05) and maintained at 12-months (6 months post-intervention). Satisfaction scores for the intervention were very high. These results suggest both feasibility and initial efficacy of this approach. Given study limitations, additional testing of this intervention as part of a larger clinical trial with objective and/or clinical outcome measures of adherence is warranted. PMID:26362167

  17. The impact of using musculoskeletal ultrasound imaging and other influencing factors on medication adherence in patients with rheumatoid arthritis: a qualitative study

    PubMed Central

    Kumar, Kanta; Raza, Karim; Gill, Paramjit; Greenfield, Sheila

    2016-01-01

    Background Medication can ease symptoms and limit disease progression in rheumatoid arthritis (RA). Despite this, nonadherence to medication is common in RA. We explored the determinants of high and low adherence to disease-modifying antirheumatic drugs (DMARDs) in patients with RA and provide suggestions on approaches to improving adherence to DMARDs. Methods Patients with RA were identified from those who had previously participated in a questionnaire measuring levels of medication adherence. Twenty patients participated (ten high and ten low adherers, as determined by responses to the Medication Adherence Report Scale). In-depth individual semistructured interviews were undertaken until data saturation was reached. Interviews were transcribed and analyzed using a constant comparative method. Results Four main themes related to adherence were identified: 1) symptom severity; 2) illness perception; 3) perceived benefits and risks of DMARDs; and 4) the quality and quantity of information about RA and DMARDs. In addition, patients’ suggestions about strategies to optimize adherence to DMARDs were captured and they fell within the following themes: 1) musculoskeletal ultrasound to explain the disease process and to provide objective feedback about the extent to which their disease activity is being effectively controlled; 2) better explanations of the consequences of poorly controlled RA; and 3) a good relationship with the health professional. Conclusion Patients’ beliefs about medicines, perceptions about RA, and level of satisfaction with information about DMARDs influenced their adherence to DMARDs. The use of musculoskeletal ultrasound to image the inflamed joint may help to improve patient adherence to DMARDs. PMID:27366054

  18. Patterned Thermoresponsive Microgel Coatings for Noninvasive Processing of Adherent Cells.

    PubMed

    Uhlig, Katja; Wegener, Thomas; He, Jian; Zeiser, Michael; Bookhold, Johannes; Dewald, Inna; Godino, Neus; Jaeger, Magnus; Hellweg, Thomas; Fery, Andreas; Duschl, Claus

    2016-03-14

    Cultivation of adherently growing cells in artificial environments is of utmost importance in medicine and biotechnology to accomplish in vitro drug screening or to investigate disease mechanisms. Precise cell manipulation, like localized control over adhesion, is required to expand cells, to establish cell models for novel therapies and to perform noninvasive cell experiments. To this end, we developed a method of gentle, local lift-off of mammalian cells using polymer surfaces, which are reversibly and repeatedly switchable between a cell-attractive and a cell-repellent state. This property was introduced through micropatterned thermoresponsive polymer coatings formed from colloidal microgels. Patterning was obtained through automated nanodispensing or microcontact printing, making use of unspecific electrostatic interactions between microgels and substrates. This process is much more robust against ambient conditions than covalent coupling, thus lending itself to up-scaling. As an example, wound healing assays were accomplished at 37 °C with highly increased precision in microfluidic environments. PMID:26879608

  19. Predictors of poor adherence among people on antiretroviral treatment in Cape Town, South Africa: a case-control study.

    PubMed

    Dewing, Sarah; Mathews, Cathy; Lurie, Mark; Kagee, Ashraf; Padayachee, Trishanta; Lombard, Carl

    2015-01-01

    A case-control study was conducted to describe the frequency with which structural- and individual-level barriers to adherence are experienced by people receiving antiretroviral (ARV) treatment and to determine predictors of non-adherence. Three hundred adherent and 300 non-adherent patients from 6 clinics in Cape Town completed the LifeWindows Information-Motivation-Behavioral Skills ART Adherence Questionnaire, the Substance Abuse and Mental Illness Symptoms Screener and the Structural Barriers to Clinic Attendance (SBCA) and Medication-taking (SBMT) scales. Overall, information-related barriers were reported most frequently followed by motivation and behaviour skill defects. Structural barriers were reported least frequently. Logistic regression analyses revealed that gender, behaviour skill deficit scores, SBCA scores and SBMT scores predicted non-adherence. Despite the experience of structural barriers being reported least frequently, structural barriers to medication-taking had the greatest impact on adherence (OR: 2.32, 95% CI: 1.73 to 3.12), followed by structural barriers to clinic attendance (OR: 2.06, 95% CI: 1.58 to 2.69) and behaviour skill deficits (OR: 1.34, 95% CI: 1.05 to 1.71). Our data indicate the need for policy directed at the creation of a health-enabling environment that would enhance the likelihood of adherence among antiretroviral therapy users. Specifically, patient empowerment strategies aimed at increasing treatment literacy and management skills should be strengthened. Attempts to reduce structural barriers to antiretroviral treatment adherence should be expanded to include increased access to mental health care services and nutrition support. PMID:25559444

  20. Examining the relationship between psychological distress and adherence to anti-retroviral therapy among Ugandan adolescents living with HIV.

    PubMed

    Mutumba, Massy; Musiime, Victor; Lepkwoski, James M; Harper, Gary W; Snow, Rachel C; Resnicow, Ken; Bauermeister, Jose A

    2016-07-01

    Psychological distress is common among adolescents living with HIV (ALHIV) worldwide, and has been associated with non-adherence to anti-retroviral therapy (ART), leading to poor virologic suppression, drug resistance, and increased risk for AIDS morbidity and mortality. However, only a few studies have explored the relationship between psychological distress and ART adherence among adolescents in sub-Saharan Africa. The paper examines the relationship between psychological distress and ART adherence, and effect of psychosocial resources on ART adherence. We conducted a cross-sectional survey of 464 ALHIV (aged 12-19; 53% female) seeking HIV care at a large HIV treatment center in Kampala, Uganda. ALHIV were recruited during routine clinic visits. Three self-reported binary adherence measures were utilized: missed pills in the past three days, non-adherence to the prescribed medical regimen, and self-rated adherence assessed using a visual analog scale. Psychological distress was measured as a continuous variable, and computed as the mean score on a locally developed and validated 25-item symptom checklist for Ugandan ALHIV. Psychosocial resources included spirituality, religiosity, optimism, social support, and coping strategies. After adjusting for respondents' socio-demographic characteristics and psychosocial resources, a unit increase in psychological distress was associated with increased odds of missing pills in past 3 days (Odds Ratio(OR) = 1.75; Confidence Interval (CI): 1.04-2.95), not following the prescribed regimen (OR = 1.63; CI: 1.08-2.46), and lower self-rated adherence (OR = 1.79; CI: 1.19-2.69). Psychosocial resources were associated with lower odds for non-adherence on all three self-report measures. There is a need to strengthen the psychosocial aspects of adolescent HIV care by developing interventions to identify and prevent psychological distress among Ugandan ALHIV. PMID:27294696