Phase, compositional, and morphological changes of human dentin after Nd:YAG laser treatment.

PubMed

Lin, C P; Lee, B S; Lin, F H; Kok, S H; Lan, W H

2001-06-01

Although techniques for repairing root fracture have been proposed, the prognosis is generally poor. If the fusion of a root fracture by laser is possible, it will offer an alternative to extraction. Our group has attempted to use lasers to fuse a low melting-point bioactive glass to fractured dentin. This report is focused on the phase, compositional, and morphological changes observed by means of X-ray diffractometer, Fourier transforming infrared spectroscopy, and scanning electron microscopy-energy dispersive X-ray spectroscopy in human dentin after exposure to Nd:YAG laser. The irradiation energies were from 150 mJ/ pulse-10 pps-4 s to 150 mJ/pulse-30 pps-4 s. After exposure to Nd:YAG laser, dentin showed four peaks on the X-ray diffractometer that corresponding to a-tricalcium phosphate (TCP) and beta-TCP at 20 = 30.78 degrees/34.21 degrees and 32.47 degrees/33.05 degrees, respectively. The peaks of a-TCP and beta-TCP gradually increased in intensity with the elevation of irradiation energy. In Fourier transforming infrared analysis, two absorption bands at 2200 cm(-1) and 2015 cm(-1) could be traced on dentin treated by Nd:YAG laser with the irradiation energies beyond 150 mJ/pulse-10 pps-4 s. The energy dispersive X-ray results showed that the calcium/phosphorus ratios of the irradiated area proportionally increased with the elevation of irradiation energy. The laser energies of 150 mJ/ pulse-30 pps-4 s and 150 mJ/pulse-20 pps-4 s could result in the a-TCP formation and collagen breakdown. However, the formation of glass-like melted substances without a-TCP at the irradiated site was induced by the energy output of 150 mJ/ pulse-10 pps-4 s. Scanning electron micrographs also revealed that the laser energy of 150 mJ/ pulse-10 pps-4 s was sufficient to prompt melting and recrystallization of dentin crystals without cracking. Therefore, we suggest that the irradiation energy of Nd:YAG laser used to fuse a low melting-point bioactive glass to dentin is 150 mJ/ pulse-10 pps-4 s.

Unique isothermal crystallization behavior of novel polyphenylene sulfide/inorganic fullerene-like WS2 nanocomposites.

PubMed

Naffakh, Mohammed; Marco, Carlos; Gómez, Marián A; Jiménez, Ignacio

2008-11-27

The isothermal crystallization of polyphenylene sulfide (PPS) nanocomposites with inorganic fullerene-like tungsten disulfide nanoparticles (IF-WS2) has been studied from a thermal and morphological point of view, using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), polarized optical microscopy (POM) and time-resolved synchrotron X-ray diffraction. All the analyses revealed that the incorporation of the IF-WS2 altered significantly the crystallization behavior of PPS, in a way strongly dependent with the nanocomposite composition. The addition of IF-WS2 in 0.1 wt % proportion retarded the crystallization of PPS by increasing its fold surface free energy in a 10%. However, addition of the nanoparticles in excess of 1 wt % results in a promotion of the crystallization rate with reduction of the fold surface free energy to half the value of pure PPS.

Measuring hospital input price increases: The rebased hospital market basket

PubMed Central

Freeland, Mark S.; Chulis, George S.; Brown, Aaron P.; Skellan, David; Maple, Brenda T.; Singer, Naphtale; Lemieux, Jeffrey; Arnett, Ross H.

1991-01-01

The input prices indexes used in part to set payment rates for Medicare inpatient hospital services in both prospective payment system (PPS) and PPS-excluded hospitals were rebased from 1982 to 1987 beginning with payments for fiscal year 1991. In this article, the issues and evidence used to determine the composition of the revised hospital input price indexes are discussed. One issue is the need for a separate market basket for PPS-excluded hospitals. Also, the payment implications of using hospital-industry versus economywide measures of wage rates as price proxies for the growth in hospital wage rates are addressed. PMID:10113610

Physicochemical properties, immunomodulation and antitumor activities of polysaccharide from Pavlova viridis.

PubMed

Sun, Liqin; Chu, Jinling; Sun, Zhongliang; Chen, Lihong

2016-01-01

Polysaccharides synthesized by microalgae can be used as the functional ingredients of food or drugs. Here, we investigated the physicochemical properties and bioactivities of the polysaccharide from microalgae Pavlova viridis, and indicated the structure-activity relationship. The polysaccharides (PPS0) were degraded with H2O2-vitamin C assisted by ultrasonic waves. The functional group content, monosaccharide composition, and average molecular weight (avg-MW) were detected by chemical or chromatographic method. The immunomodulatory activities were evaluated in vitro by detecting nitric oxide (NO) emission, neutral red uptake and macrophage proliferation. Antitumor activities of degraded fragments were detected using S180-tumor-bearing mouse model by intragastric administration. Degraded polysaccharides PPS1 and PPS2 were obtained at avg-MW of 386.96 and 54.99 kDa. The sulfate group content of polysaccharide was 16%, and the uronic acid content was 5.88 and 8.48%. PPS mainly consisted of fructose, glucose and mannose. All the degraded PPSs could increase phagocytosis and proliferation of macrophages, and stimulated NO emission in a dose-dependently way. PPS2 in Low-MW fragments had the strongest immunoenhancing activities. Different doses of PPS all could inhibit the growth of implanted S180 tumor. At dose of 200 mg/kg/day, the tumor inhibition rate of PPS2 was 57.06%, about 23.6% less than that of CTX-treated group. Different-MW PPS significantly increased lymphocyte proliferation. At 200 mg/L, the proliferation index of PPS2 was 1.37, 2.03 times higher than that of CTX-treated group. The polysaccharides of Pavlova viridis had potential antitumor activities by improving immune response. Moreover, the bioactivities depend on their molecular weight. Copyright © 2015 Elsevier Inc. All rights reserved.

Stormwater harvesting for irrigation purposes: an investigation of chemical quality of water recycled in pervious pavement system.

PubMed

Nnadi, Ernest O; Newman, Alan P; Coupe, Stephen J; Mbanaso, Fredrick U

2015-01-01

Most available water resources in the world are used for agricultural irrigation. Whilst this level of water use is expected to increase due to rising world population and land use, available water resources are expected to become limited due to climate change and uneven rainfall distribution. Recycled stormwater has the potential to be used as an alternative source of irrigation water and part of sustainable water management strategy. This paper reports on a study to investigate whether a sustainable urban drainage system (SUDS) technique, known as the pervious pavements system (PPS) has the capability to recycle water that meets irrigation water quality standard. Furthermore, the experiment provided information on the impact of hydrocarbon (which was applied to simulate oil dripping from parked vehicles onto PPS), leaching of nutrients from different layers of the PPS and effects of nutrients (applied to enhance bioremediation) on the stormwater recycling efficiency of the PPS. A weekly dose of 6.23 × 10(-3) L of lubricating oil and single dose of 17.06 g of polymer coated controlled-release fertilizer granules were applied to the series of 710 mm × 360 mm model pervious pavement structure except the controls. Rainfall intensity of 7.4 mm/h was applied to the test models at the rate of 3 events per week. Analysis of the recycled water showed that PPS has the capability to recycle stormwater to a quality that meets the chemical standards for use in agricultural irrigation irrespective of the type of sub-base used. There is a potential benefit of nutrient availability in recycled water for plants, but care should be taken not to dispose of this water in natural water courses as it might result in eutrophication problems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Unique nucleation activity of inorganic fullerene-like WS2 nanoparticles in polyphenylene sulfide nanocomposites: isokinetic and isoconversional study of dynamic crystallization kinetics.

PubMed

Naffakh, Mohammed; Marco, Carlos; Gómez, Marián A; Jiménez, Ignacio

2009-05-21

The dynamic crystallization kinetics of polyphenylene sulfide (PPS) nanocomposites with inorganic fullerene WS2 nanopartices (IF-WS2) content varying from 0.05 to 8 wt % has been studied using differential scanning calorimetry (DSC). The analysis of the crystallization at different cooling rates demonstrates that the completely isokinetic description of the crystallization process is not possible. However, the isoconversional methods in combination with the JMAEK equation provide a better understanding of the kinetics of the dynamic crystallization process. The addition of IF-WS2 influences the crystallization kinetics of PPS but in ways unexpected for polymer nanocomposites. A drastic change from retardation to promotion of crystallization is observed with increasing nanoparticle content. In the same way, the results of the nucleation activity and the effective energy barrier confirmed the unique dependence of the crystallization behavior of PPS on composition. In addition, the morphological data obtained from the polarized optical microscopy (POM) and time-resolved synchrotron X-ray diffraction is consistent with results of the crystallization kinetics of PPS/IF-WS2 nanocomposites.

Inorganic Nanoparticle-Modified Poly(Phenylene Sulphide)/ Carbon Fiber Laminates: Thermomechanical Behaviour.

PubMed

Díez-Pascual, Ana M; Naffakh, Mohammed

2013-07-26

Carbon fiber (CF)-reinforced high-temperature thermoplastics such as poly(phenylene sulphide) (PPS) are widely used in structural composites for aerospace and automotive applications. The porosity of CF-reinforced polymers is a very important topic for practical applications since there is a direct correlation between void content and mechanical properties. In this study, inorganic fullerene-like tungsten disulphide (IF-WS₂) lubricant nanoparticles were used to manufacture PPS/IF-WS₂/CF laminates via melt-blending and hot-press processing, and the effect of IF-WS₂ loading on the quality, thermal and mechanical behaviour of the hybrid composites was investigated. The addition of IF-WS₂ improved fiber impregnation, resulting in lower degree of porosity and increased delamination resistance, compression and flexural properties; their reinforcement effect was greater at temperatures above the glass transition (T g ). IF-WS₂ contents higher than 0.5 wt % increased T g and the heat deflection temperature while reduced the coefficient of thermal expansion. The multiscale laminates exhibited higher ignition point and notably reduced peak heat release rate compared to PPS/CF. The coexistence of micro- and nano-scale fillers resulted in synergistic effects that enhanced the stiffness, strength, thermal conductivity and flame retardancy of the matrix. The results presented herein demonstrate that the IF-WS₂ are very promising nanofillers to improve the thermomechanical properties of conventional thermoplastic/CF composites.

Inorganic Nanoparticle-Modified Poly(Phenylene Sulphide)/Carbon Fiber Laminates: Thermomechanical Behaviour

PubMed Central

Díez-Pascual, Ana M.; Naffakh, Mohammed

2013-01-01

Carbon fiber (CF)-reinforced high-temperature thermoplastics such as poly(phenylene sulphide) (PPS) are widely used in structural composites for aerospace and automotive applications. The porosity of CF-reinforced polymers is a very important topic for practical applications since there is a direct correlation between void content and mechanical properties. In this study, inorganic fullerene-like tungsten disulphide (IF-WS2) lubricant nanoparticles were used to manufacture PPS/IF-WS2/CF laminates via melt-blending and hot-press processing, and the effect of IF-WS2 loading on the quality, thermal and mechanical behaviour of the hybrid composites was investigated. The addition of IF-WS2 improved fiber impregnation, resulting in lower degree of porosity and increased delamination resistance, compression and flexural properties; their reinforcement effect was greater at temperatures above the glass transition (Tg). IF-WS2 contents higher than 0.5 wt % increased Tg and the heat deflection temperature while reduced the coefficient of thermal expansion. The multiscale laminates exhibited higher ignition point and notably reduced peak heat release rate compared to PPS/CF. The coexistence of micro- and nano-scale fillers resulted in synergistic effects that enhanced the stiffness, strength, thermal conductivity and flame retardancy of the matrix. The results presented herein demonstrate that the IF-WS2 are very promising nanofillers to improve the thermomechanical properties of conventional thermoplastic/CF composites. PMID:28811429

Conductive films of silver nanoparticles as novel susceptors for induction welding of thermoplastic composites

NASA Astrophysics Data System (ADS)

Dermanaki Farahani, Rouhollah; Janier, Mathieu; Dubé, Martine

2018-03-01

In the present work, a conductive film of silver nanoparticles (nAg) as a novel heating element type, called susceptor, was developed and tested for induction welding of carbon fiber/polyphenylene sulfide (CF/PPS) thermoplastic composites, i.e., unidirectional pre-impregnated 16 plies of CF/PPS compression-molded in a quasi-isotropic stacking sequence. The nAg were synthesized, dispersed in deionized (DI) water and casted onto a pure PPS film, resulting in a conductive film upon the evaporation of DI water and thermal post-annealing. The thermal annealing at 250 °C significantly (by 7 orders) decreased the film’s electrical resistivity from 9.4 × 103 down to 3.1 × 10-4 Ω cm. The new susceptors led to fast heating rates in induction welding when compared to the standard stainless steel mesh susceptors under similar welding conditions. Lap shear mechanical testing revealed that the apparent lap shear strength (LSS) is sensitive to the susceptors’ resistivity and the input current. A relatively high LSS value was achieved for the specimens welded using the new susceptors which exceeded the value of those welded using stainless steel mesh susceptors (28.3 MPa compared to 20 MPa). The weld interface and specimens’ cross-section observation revealed that the nAg were dispersed and embedded into the resin upon welding. This study contains preliminary results that show high potential of nanoparticles as effective susceptors to further improve the mechanical performance of the joints in welding of thermoplastic composites.

Influence of Superhydrophobic Properties on Deicing

NASA Astrophysics Data System (ADS)

Nazhipkyzy, M.; Mansurov, Z. A.; Amirfazli, A.; Esbosin, A.; Temirgaliyeva, T. S.; Lesbayev, B. T.; Aliyev, E. T.; Prikhodko, N. G.

2016-11-01

Nowadays the creation of anti-icing, or deicing, surfaces is one of the most important problems, as such surfaces are widely used in aeronautics, wind turbines, and telecommunication antennas. In this paper, we focus mainly on reducing the ice adhesion forces and easy ice removal, once ice has formed. Removal of a liquid from a surface can be provided by modification of the surface wettability by means of applying superhydrophobic coatings. Such coatings are water-resistant, i.e., are characterized by low water adhesion forces. To study the impact of superhydrophobic coatings, tests were performed on the surface of a wing in a wind tunnel. By spraying Teflon and polyphenylene sulfide (PPS) on the wing, we obtained a superhydrophobic film. This film has a structure that provides superhydrophobic properties, so that the wetting angle is above 140°. A comparison of the resulting surface with a clean Teflon one shows that adhesion of the Teflon + PPS mixture to an aluminum surface is five times higher. We also investigate the degree of ice formation on the surfaces of simple and superhydrophobic aircraft wings at a temperature of -18°C. It was shown that ice was formed on a simple wing within 40 s and on a superhydrophobic wing within 25 s. When the simple wing with a mass of 23 g was inserted into the wind tunnel, its mass reached 50 g, and for a superhydrophobic wing with a mass of 26 g the latter reached 42 g. The sample of the airfoil wing we prepared has a low adhesion, which helps in easy ice removal.

Conductive films of silver nanoparticles as novel susceptors for induction welding of thermoplastic composites.

PubMed

Farahani, Rouhollah Dermanaki; Janier, Mathieu; Dubé, Martine

2018-03-23

In the present work, a conductive film of silver nanoparticles (nAg) as a novel heating element type, called susceptor, was developed and tested for induction welding of carbon fiber/polyphenylene sulfide (CF/PPS) thermoplastic composites, i.e., unidirectional pre-impregnated 16 plies of CF/PPS compression-molded in a quasi-isotropic stacking sequence. The nAg were synthesized, dispersed in deionized (DI) water and casted onto a pure PPS film, resulting in a conductive film upon the evaporation of DI water and thermal post-annealing. The thermal annealing at 250 °C significantly (by 7 orders) decreased the film's electrical resistivity from 9.4 × 10 3 down to 3.1 × 10 -4 Ω cm. The new susceptors led to fast heating rates in induction welding when compared to the standard stainless steel mesh susceptors under similar welding conditions. Lap shear mechanical testing revealed that the apparent lap shear strength (LSS) is sensitive to the susceptors' resistivity and the input current. A relatively high LSS value was achieved for the specimens welded using the new susceptors which exceeded the value of those welded using stainless steel mesh susceptors (28.3 MPa compared to 20 MPa). The weld interface and specimens' cross-section observation revealed that the nAg were dispersed and embedded into the resin upon welding. This study contains preliminary results that show high potential of nanoparticles as effective susceptors to further improve the mechanical performance of the joints in welding of thermoplastic composites.

Impregnation quality of shredded semipreg after compression moulding

NASA Astrophysics Data System (ADS)

Vincent, G.; Balakrishnan, V.; de Bruijn, T. A.; Wijskamp, S.; Abdul Rasheed, M. I.

2017-10-01

Manufacturing of thermoplastic composites (TPC) inherently generates scrap, mainly in the form of offcuts or rejected parts. The growth of TPC over recent decades has now reached a point where developing specific recycling solutions for TPC waste has become crucial. While looking at the various steps during which scrap is produced, the nesting of semipreg or prepreg appears to be critical. This work aims to develop a route for recycling semipreg offcuts, comprising shredding and compression moulding. This article focuses on an experimental study of the compression moulding step of carbon fibres reinforced PPS (C/PPS) to investigate the uniformity and impregnation quality of plates. These plates were realised in a picture frame while varying both the fibre volume content between 30% and 50% and the processing parameters. Visual inspection and cross-sectional microscopy were performed to assess the quality of each plate. As a first step, the influence of the type of added matrix (film, powder, pellets) and the type of pre-impregnation (film, powder) was studied. Stacking of polymer powder with shredded powder-coated semipreg gave the best impregnation quality. It was also shown that longer dwell time at melt leads to better consolidation quality. However, the difficulty in obtaining good impregnation comes from the disentangled shredded material, which is composed of three forms: semipreg flakes, dry bundles and pieces of matrix. When dry bundles reach the mould surfaces during the filling of the mould or when they are packed together, the consolidation cycle hardly impregnates them and they remain dry afterwards. Furthermore, large local variations of fibre fraction were noticed, resulting from a random mould filling. Therefore, the recycling solution for shredded semipreg is feasible when the fibre fraction is reduced but improvements on the part variability still have to be made.

Pneumococcal vaccination in patients with systemic lupus erythematosus: A multicenter placebo-controlled randomized double-blind study.

PubMed

Grabar, Sophie; Groh, Matthieu; Bahuaud, Mathilde; Le Guern, Véronique; Costedoat-Chalumeau, Nathalie; Mathian, Alexis; Hanslik, Thomas; Guillevin, Loïc; Batteux, Frédéric; Launay, Odile

2017-09-05

Invasive pneumococcal disease and respiratory tract infections are both frequent and severe in patients with systemic lupus erythematosus (SLE). This study aimed to compare the immunological efficacy and safety of pneumococcal vaccination with the 23-valent polysaccharide (PPS) vaccine alone to a sequential immunization with the 7-valent pneumococcal conjugate (PnCj) vaccine followed by PPS in patients with SLE and stable diseaase. Multicenter randomized placebo-controlled double-blind trial: PPS vaccine alone (placebo-PPS group) or PnCj vaccine followed by PPS vaccine (PnCj-PPS group) 24weeks later. The primary endpoint was the rate of responders at week 28 to at least 5 of the 7 serotypes (4, 6B, 9V, 14, 18C, 19F and 23F) shared by both PPS and PnCj. Pneumococcal IgG antibodies' opsonophagocytic activity (OPA) were also assessed. Twenty-five patients in the placebo-PPS group and 17 in the PnCj-PPS group were included in a modified intention-to-treat analysis. The primary endpoint was reached in 72% (18/25) in the placebo-PPS and 76% (13/17) in the PnCj-PPS group (p=0.75). There was no difference in the rates of responders with OPA. At week 52, 13/18 (72%) patients in the placebo-PPS group and 10/13 (77%) patients in the PnCj-PPS group (p=0.77) that met the primary endpoint at week 28 were still responders to ≥5/7 serotypes shared by both PPS and PnCj vaccines. Nine SLE flares were reported in 6 patients (4 in the placebo-PPS and 2 in the PnCj-PPS groups respectively, p=0.70). Sequential administration of PnCj vaccine followed by PPS vaccine is safe and shows short-term immunological efficacy in patients with SLE but was not superior to the PPS vaccine alone. www.clinicaltrials.gov, NCT NCT00611663. Copyright © 2017 Elsevier Ltd. All rights reserved.

Metalloporphyrin-based porous polymers prepared via click chemistry for size-selective adsorption of protein.

PubMed

Zhu, Dailian; Qin, Cunqi; Ao, Shanshi; Su, Qiuping; Sun, Xiying; Jiang, Tengfei; Pei, Kemei; Ni, Huagang; Ye, Peng

2018-08-01

Zinc porphyrin-based porous polymers (PPs-Zn) with different pore sizes were prepared by controlling the reaction condition of click chemistry, and the protein adsorption in PPs-Zn and the catalytic activity of immobilized enzyme were investigated. PPs-Zn-1 with 18 nm and PPS-Zn-2 with 90 nm of pore size were characterized by FTIR, NMR and nitrogen absorption experiments. The amount of adsorbed protein in PPs-Zn-1 was more than that in PPs-Zn-2 for small size proteins, such as lysozyme, lipase and bovine serum albumin (BSA). And for large size proteins including myosin and human fibrinogen (HFg), the amount of adsorbed protein in PPs-Zn-1 was less than that in PPs-Zn-2. The result indicates that the protein adsorption is size-selective in PPs-Zn. Both the protein size and the pore size have a significant effect on the amount of adsorbed protein in the PPs-Zn. Lipase and lysozyme immobilized in PPs-Zn exhibited excellent reuse stability.

The Association Between Physical Performance and Executive Function in a Sample of Rural Older Adults from South Carolina, USA.

PubMed

Falck, Ryan S; Wilcox, Sara; Best, John R; Chandler, Jessica L; Liu-Ambrose, Teresa

2017-01-01

Mobility and executive functions (EFs) decline with age, although associations between mobility and EFs are less clear. This study examined relationships between different mobility measures and EFs among rural older adults. This cross-sectional study recruited 56 older adults (60+ years) in rural South Carolina. Mobility was assessed via gait speed, timed up-and-go, chair stand, and as a composite physical performance score (PPS). EFs was assessed via Trail Making Test, semantic fluency, and phonemic fluency. Bivariate analyses were performed and regressions were calculated controlling for appropriate covariates, with PPS as the independent variable and each EF test as the dependent variable. Mean age was 74.22 years (SD = 8.02), 80.40% were female and 64.71% were white. Bivariate analysis revealed associations between gait speed and Trail Making Test (r = -.33; p = .03), between timed up-and-go and Trail Making Test (r = .34; p = .01), and between PPS and Trail Making Test (r = -.33; p = .03). The regression models indicated higher PPS was associated with better performance on Trail Making Test (β = -1.12; p < 0.01), phonemic fluency (β = 0.68; p = .01), and semantic fluency (β = 0.81; p = .02). In a rural setting, mobility is associated with multiple EF processes. Higher mobility and physical ability are desired for maintaining EFs capability.

Pneumococcal Polysaccharide Abrogates Conjugate-Induced Germinal Center Reaction and Depletes Antibody Secreting Cell Pool, Causing Hyporesponsiveness

PubMed Central

Bjarnarson, Stefania P.; Benonisson, Hreinn; Del Giudice, Giuseppe; Jonsdottir, Ingileif

2013-01-01

Background Plain pneumococcal polysaccharide (PPS) booster administered during second year of life has been shown to cause hyporesponsiveness. We assessed the effects of PPS booster on splenic memory B cell responses and persistence of PPS-specific long-lived plasma cells in the bone marrow (BM). Methods Neonatal mice were primed subcutanously (s.c.) or intranasally (i.n.) with pneumococcal conjugate (Pnc1-TT) and the adjuvant LT-K63, and boosted with PPS+LT-K63 or saline 1, 2 or 3 times with 16 day intervals. Seven days after each booster, spleens were removed, germinal centers (GC), IgM+, IgG+ follicles and PPS-specific antibody secreting cells (AbSC) in spleen and BM enumerated. Results PPS booster s.c., but not i.n., compromised the Pnc1-TT-induced PPS-specific Abs by abrogating the Pnc1-TT-induced GC reaction and depleting PPS-specific AbSCs in spleen and limiting their homing to the BM. There was no difference in the frequency of PPS-specific AbSCs in spleen and BM between mice that received 1, 2 or 3 PPS boosters s.c.. Repeated PPS+LT-K63 booster i.n. reduced the frequency of PPS-specific IgG+ AbSCs in BM. Conclusions PPS booster-induced hyporesponsiveness is caused by abrogation of conjugate-induced GC reaction and depletion of PPS-specific IgG+ AbSCs resulting in no homing of new PPS-specific long-lived plasma cells to the BM or survival. These results should be taken into account in design of vaccination schedules where polysaccharides are being considered. PMID:24069152

Financial implications of choice of dialysis type of the revised Medicare payment system: an economic analysis.

PubMed

Hornberger, John; Hirth, Richard A

2012-08-01

In 2011, the Medicare Improvements for Patients and Providers Act replaced the case-mix-adjusted composite payment system for Medicare outpatient dialysis facilities with a bundled end-stage renal disease prospective payment system (PPS). We assessed the economic implications for modality choice of the revised Medicare payment system. Microeconomic analyses. Patients eligible for dialysis in the United States. The perspective of this analysis is that of a financial administrator of a representative dialysis center in the United States. Data were obtained from the Medicare Payment Advisory Commission, the US Renal Data System, the DOPPS (Dialysis Outcomes and Practice Patterns Study) Practice Monitor, the US Bureau of Labor Statistics, and Medicare fee schedules. Recently implemented end-stage renal disease PPS versus the prior case-mix composite payment system. Medicare payment per month, center fixed and variable costs per month, net difference in revenue and variable costs (direct contribution), and net difference in revenue and total costs (operating margin). The direct contribution and operating margin for in-center hemodialysis and peritoneal dialysis are expected to be positive under the new bundled PPS. For Medicare fiscal intermediaries/administrators, paid treatments for home hemodialysis vary from 3.2 to more than 4.8 per week. The direct contribution and operating margin are expected to be negative for home hemodialysis if the number of paid treatments is similar between in-center and home hemodialysis; they are almost identical when the number of paid treatments increases for home hemodialysis by approximately 1 per week. Experience across centers and intermediaries/administrators may vary. Sensitivity analyses were conducted to assess the robustness of findings and determine which variables most influenced results. The new bundled PPS created a financial incentive for increased use of peritoneal dialysis. Use of home hemodialysis may be influenced by number of paid treatments per week. Copyright © 2012 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Effects of extraction methods on the yield, chemical structure and anti-tumor activity of polysaccharides from Cordyceps gunnii mycelia.

PubMed

Zhu, Zhen-Yuan; Dong, Fengying; Liu, Xiaocui; Lv, Qian; YingYang; Liu, Fei; Chen, Ling; Wang, Tiantian; Wang, Zheng; Zhang, Yongmin

2016-04-20

This study was to investigate the effects of different extraction methods on the yield, chemical structure and antitumor activity of polysaccharides from Cordyceps gunnii (C. gunnii) mycelia. Five extraction methods were used to extract crude polysaccharides (CPS), which include room-temperature water extraction (RWE), hot-water extraction (HWE), microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE) and cellulase-assisted extraction (CAE). Then Sephadex G-100 was used for purification of CPS. As a result, the antitumor activities of CPS and PPS on S180 cells were evaluated. Five CPS and purified polysaccharides (PPS) were obtained. The yield of CPS by microwave-assisted extraction (CPSMAE) was the highest and its anti-tumor activity was the best and its macromolecular polysaccharide (3000-1000kDa) ratio was the largest. The PPS had the same monosaccharide composition, but their obvious difference was in the antitumor activity and the physicochemical characteristics, such as intrinsic viscosity, specific rotation, scanning electron microscopy and circular dichroism spectra. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pine polyphenols from Pinus koraiensis prevent injuries induced by gamma radiation in mice

PubMed Central

Li, Hui; Xu, Yier; Sun, Guicai

2016-01-01

Pine polyphenols (PPs) are bioactive dietary constituents that enhance health and help prevent diseases through antioxidants. Antioxidants reduce the level of oxidative damages caused by ionizing radiation (IR). The main purpose of this paper is to study the protective effect of PPs on peripheral blood, liver and spleen injuries in mice induced by IR. ICR (Institute of Cancer Research) male mice were administered orally with PPs (200 mg/kg b.wt.) once daily for 14 consecutive days prior to 7 Gy γ-radiations. PPs showed strong antioxidant activities. PPs significantly increased white blood cells, red blood cells and platelets counts. PPs also significantly reduced lipid peroxidation and increased the activities of superoxide dismutase, catalase and glutathione peroxidases, and the level of glutathione. PPs reduced the spleen morphologic injury. In addition, PPs inhibited mitochondria-dependent apoptosis pathways in splenocytes induced by IR. These results indicate that PPs are radioprotective promising reagents. PMID:27069807

Durability-Based Design Criteria for a Quasi-Isotropic Carbon-Fiber-Reinforced Thermoplastic Automotive Composite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naus, Dan J; Corum, James; Klett, Lynn B

2006-04-01

This report provides recommended durability-based design properties and criteria for a quais-isotropic carbon-fiber thermoplastic composite for possible automotive structural applications. The composite consisted of a PolyPhenylene Sulfide (PPS) thermoplastic matrix (Fortron's PPS - Ticona 0214B1 powder) reinforced with 16 plies of carbon-fiber unidirectional tape, [0?/90?/+45?/-45?]2S. The carbon fiber was Hexcel AS-4C and was present in a fiber volume of 53% (60%, by weight). The overall goal of the project, which is sponsored by the U.S. Department of Energy's Office of Freedom Car and Vehicle Technologies and is closely coordinated with the Advanced Composites Consortium, is to develop durability-driven design datamore » and criteria to assure the long-term integrity of carbon-fiber-based composite systems for automotive structural applications. This document is in two parts. Part 1 provides design data and correlations, while Part 2 provides the underlying experimental data and models. The durability issues addressed include the effects of short-time, cyclic, and sustained loadings; temperature; fluid environments; and low-energy impacts (e.g., tool drops and kickups of roadway debris) on deformation, strength, and stiffness. Guidance for design analysis, time-independent and time-dependent allowable stresses, rules for cyclic loadings, and damage-tolerance design guidance are provided.« less

Restless legs syndrome and post polio syndrome: a case-control study.

PubMed

Romigi, A; Pierantozzi, M; Placidi, F; Evangelista, E; Albanese, M; Liguori, C; Nazzaro, M; Risina, B U; Simonelli, V; Izzi, F; Mercuri, N B; Desiato, M T

2015-03-01

The aim was to investigate the prevalence of restless legs syndrome (RLS), fatigue and daytime sleepiness in a large cohort of patients affected by post polio syndrome (PPS) and their impact on patient health-related quality of life (HRQoL) compared with healthy subjects. PPS patients were evaluated by means of the Stanford Sleepiness Scale and the Fatigue Severity Scale (FSS). The Short Form Health Survey (SF-36) questionnaire was utilized to assess HRQoL in PPS. RLS was diagnosed when standard criteria were met. Age and sex matched healthy controls were recruited amongst spouses or friends of PPS subjects. A total of 66 PPS patients and 80 healthy controls were enrolled in the study. A significantly higher prevalence of RLS (P < 0.0005; odds ratio 21.5; 95% confidence interval 8.17-57) was found in PPS patients (PPS/RLS+ 63.6%) than in healthy controls (7.5%). The FSS score was higher in PPS/RLS+ than in PPS/RLS- patients (P = 0.03). A significant decrease of SF-36 scores, including the physical function (P = 0.001), physical role (P = 0.0001) and bodily pain (P = 0.03) domains, was found in PPS/RLS+ versus PPS/RLS- patients. Finally, it was found that PPS/RLS+ showed a significant correlation between International Restless Legs Scale score and FSS (P < 0.0001), as well as between International Restless Legs Scale score and most of the SF-36 items (physical role P = 0.0018, general health P = 0.0009, vitality P = 0.0022, social functioning P = 0.002, role emotional P = 0.0019, and mental health P = 0.0003). Our findings demonstrate a high prevalence of RLS in PPS, and that RLS occurrence may significantly influence the HRQoL and fatigue of PPS patients. A hypothetical link between neuroanatomical and inflammatory mechanisms in RLS and PPS is suggested. © 2014 EAN.

Evidence that Altered Cis Element Spacing Affects PpsR Mediated Redox Control of Photosynthesis Gene Expression in Rubrivivax gelatinosus.

PubMed

Shimizu, Takayuki; Cheng, Zhuo; Matsuura, Katsumi; Masuda, Shinji; Bauer, Carl E

2015-01-01

PpsR is a major regulator of photosynthesis gene expression among all characterized purple photosynthetic bacteria. This transcription regulator has been extensively characterized in Rhodobacter (Rba.) capsulatus and Rba. sphaeroides which are members of the α-proteobacteria lineage. In this study, we have investigated the biochemical properties and mutational effects of a ppsR deletion strain in the β-proteobacterium Rubrivivax (Rvi.) gelatinosus in order to reveal phylogenetically conserved mechanisms and species-specific characteristics. A deletion of the ppsR gene resulted in de-repression of photosystem synthesis showing that PpsR functions as a repressor of photosynthesis genes in this species. We also constructed a Rvi. gelatinosus PpsR mutant in which a conserved cysteine at position 436 was changed to an alanine to examine whether or not this residue is important for sensing redox, as reported in Rhodobacter species. Surprisingly, the Cys436 Ala mutant retained the ability to repress photosynthesis gene expression under aerobic conditions, suggesting that PpsR from Rvi. gelatinosus has different redox-responding characteristics. Furthermore, biochemical analyses demonstrated that Rvi. gelatinosus PpsR only shows redox-dependent binding to promoters with 9-bp spacing, but not 8-bp spacing, between two PpsR-recognition sequences. These results indicate that redox-dependent binding of PpsR requires appropriate cis configuration of PpsR target sequences in Rvi. gelatinosus. These results also indicate that PpsR homologs from different species regulate photosynthesis genes with altered biochemical properties.

Association between painful physical symptoms and clinical outcomes in East Asian patients with major depressive disorder: a 3-month prospective observational study.

PubMed

Ang, Q Q; Wing, Y K; He, Y; Sulaiman, A H; Chiu, N-Y; Shen, Y-C; Wang, G; Zhang, C; Lee, K-H; Singh, P; Granger, R E; Raskin, J; Dossenbach, M

2009-07-01

Reports from non-Asian populations indicate that painful physical symptoms (PPS) are associated with poorer clinical and functional outcomes in major depressive disorder (MDD). The purpose of this study is to report comparative changes in disease severity, treatment patterns and quality of life observed in East Asian patients with MDD, with and without PPS, as assessed prospectively over a 3-month observation period. This observational study enrolled 909 patients with MDD in psychiatric care settings in China, Hong Kong, Korea, Malaysia, Singapore and Taiwan. Patients were classified as PPS positive (PPS+) or negative (PPS-) based on mean modified Somatic Symptom Inventory scores of >or= 2 or < 2 respectively. The Clinical Global Impression of Severity (CGI-S) and 17-item Hamilton Depression Rating Scale (HAMD(17)) determined depression severity; a visual analogue scale (VAS) determined pain severity; and the EuroQoL (EQ-5D) assessed well-being after 3 months observation. Of the 909 enrollees, 355/471 (75.4%) of PPS+ patients and 363/438 (82.9%) of PPS- patients completed the study (p = 0.006). PPS+ patients improved less than PPS- patients on depression, pain and quality of life measures during the study (HAMD(17) p < 0.001, CGI-S p < 0.001, VAS p = 0.008 and EQ-5D p = 0.004). Fewer PPS+ patients (46.5%) achieved remission compared with PPS- patients (69.4%, p < 0.001). As the presence of PPS is associated with poorer outcomes in East Asian MDD patients, clinical management should aim to address both the mental and PPS associated with MDD.

Folic acid conjugated mPEG-PEI600 as an efficient non-viral vector for targeted nucleic acid delivery.

PubMed

Xu, Zhenhua; Jin, Jiefu; Siu, Leo K S; Yao, Hong; Sze, Johnny; Sun, Hongzhe; Kung, Hsiang-Fu; Poon, Wai Sang; Ng, Samuel S M; Lin, Marie C

2012-04-15

In this study we describe a novel polymer, mPPS-FA, synthesized as a potential gene transfer vector. To complete mPPS-FA, folic acid was conjugated to a backbone (named mPPS) consisting of a copolymer of methyl PEG-2000, PEI-600, and sebacoyl chloride. (1)H NMR, FT-IR, and UV spectroscopy were used to characterize the structure of mPPS-FA. It was revealed that mPPS-FA holds the ability to bind plasmid DNA yielding positively charged particles (polyplexes). Dynamic light scattering (DLS) and TEM techniques were used to study the size and morphology of the formed mPPS-FA/DNA nanocomplexes. The mPPS-FA/DNA nanoparticles exhibited low cytotoxicity as transfection of B16-F0, U87MG, CHO-1, and Ho-8910 cells produced >80% viability indicating low cytotoxicity of the polymer. The ability of mPPS-FA to deliver EGFP plasmid to melanoma B16-F0, U87, CHO-1, Ho-8910, and A549 cells was investigated in vitro as compared to the lipid-based transfection agent Lipofectamine2000 and Linear PEI 22 kDa (L-PEI 22 kDa). We found that mPPS-FA/DNA complexes yielded the highest GFP transfection efficiency in B16-F0, U87, CHO-1, and Ho-8910 cells, which all highly express folate receptors (FR), at an mPPS-FA/DNA ratio (w/w) of 15. Furthermore, the transfection of mPPS-FA/DNA complexes in CHO-1 cells could be competitively blocked by free folic acid molecules. In contrast, in low FR expressing A549 cells, mPPS-FA showed similar low transfection efficiency as mPPS. Taken together, mPPS-FA showed the highest efficiency in vitro and the potential to be developed as a nonviral gene carrier. Copyright © 2012 Elsevier B.V. All rights reserved.

A reliability and validity study of the Palliative Performance Scale

PubMed Central

Ho, Francis; Lau, Francis; Downing, Michael G; Lesperance, Mary

2008-01-01

Background The Palliative Performance Scale (PPS) was first introduced in1996 as a new tool for measurement of performance status in palliative care. PPS has been used in many countries and has been translated into other languages. Methods This study evaluated the reliability and validity of PPS. A web-based, case scenarios study with a test-retest format was used to determine reliability. Fifty-three participants were recruited and randomly divided into two groups, each evaluating 11 cases at two time points. The validity study was based on the content validation of 15 palliative care experts conducted over telephone interviews, with discussion on five themes: PPS as clinical assessment tool, the usefulness of PPS, PPS scores affecting decision making, the problems in using PPS, and the adequacy of PPS instruction. Results The intraclass correlation coefficients for absolute agreement were 0.959 and 0.964 for Group 1, at Time-1 and Time-2; 0.951 and 0.931 for Group 2, at Time-1 and Time-2 respectively. Results showed that the participants were consistent in their scoring over the two times, with a mean Cohen's kappa of 0.67 for Group 1 and 0.71 for Group 2. In the validity study, all experts agreed that PPS is a valuable clinical assessment tool in palliative care. Many of them have already incorporated PPS as part of their practice standard. Conclusion The results of the reliability study demonstrated that PPS is a reliable tool. The validity study found that most experts did not feel a need to further modify PPS and, only two experts requested that some performance status measures be defined more clearly. Areas of PPS use include prognostication, disease monitoring, care planning, hospital resource allocation, clinical teaching and research. PPS is also a good communication tool between palliative care workers. PMID:18680590

Doxycycline alters collagen composition following ventral hernia repair.

PubMed

Tharappel, Job C; Harris, Jennifer W; Totten, Crystal; Zwischenberger, Brittany A; Roth, John S

2017-04-01

Doxycycline, a nonspecific metalloproteinase (MMP) inhibitor, has been demonstrated to impact the strength of the polypropylene (PP) mesh-repaired hernia with an increase in the deposition of collagen type 1. The impact of doxycycline with porcine acellular dermal matrices (PADM) is unknown; therefore, we evaluated the impact of doxycycline administration upon hernia repair with PP and PADM mesh. Sprague-Dawley rats weighing ~400 g underwent laparotomy with creation of a midline ventral hernia. After a 27-day recovery, animals were randomly assigned to four groups of eight and underwent intraperitoneal underlay hernia repair with either PP or PADM. Groups were assigned to daily normal saline (S) or daily doxycycline in normal saline 10 mg/kg (D) via oral gavage for 8 weeks beginning 24 h preoperatively. Animals were euthanized at 8 weeks and underwent tensiometric testing of the abdominal wall and western blot analyses for collagen subtypes and MMPs. Thirty-two animals underwent successful hernia creation and repair with either PADM or PP. At 8 weeks, 15 of 16 PP-implanted animals survived with only 12 of 16 PADM-implanted animals surviving. There were no differences in the mesh to fascial interface tensiometric strength between groups. Densitometric counts in the PADM-D group demonstrated increased collagen type 1 compared to PP-S (PADM-D [1286.5], PADM-S [906.9], PP-S [700.4], p = 0.037) and decreased collagen type 3 compared to PP-S (PADM-D [7446.9], PADM-S [8507.6], PP-S [11,297.1], p = 0.01). MMP-9 levels were increased in PADM-D (PP-S vs. PADM-D, p = 0.04), while MMP-2 levels were similar between PADM-D and PADM-S, respectively. Collagen type 1 deposition at the mesh to fascial interface is enhanced following administration of doxycycline in ventral hernia repairs with porcine acellular dermal matrices. Doxycycline administration may have implications for enhancing hernia repair outcomes using biologic mesh.

Mission Operations Center (MOC) - Precipitation Processing System (PPS) Interface Software System (MPISS)

NASA Technical Reports Server (NTRS)

Ferrara, Jeffrey; Calk, William; Atwell, William; Tsui, Tina

2013-01-01

MPISS is an automatic file transfer system that implements a combination of standard and mission-unique transfer protocols required by the Global Precipitation Measurement Mission (GPM) Precipitation Processing System (PPS) to control the flow of data between the MOC and the PPS. The primary features of MPISS are file transfers (both with and without PPS specific protocols), logging of file transfer and system events to local files and a standard messaging bus, short term storage of data files to facilitate retransmissions, and generation of file transfer accounting reports. The system includes a graphical user interface (GUI) to control the system, allow manual operations, and to display events in real time. The PPS specific protocols are an enhanced version of those that were developed for the Tropical Rainfall Measuring Mission (TRMM). All file transfers between the MOC and the PPS use the SSH File Transfer Protocol (SFTP). For reports and data files generated within the MOC, no additional protocols are used when transferring files to the PPS. For observatory data files, an additional handshaking protocol of data notices and data receipts is used. MPISS generates and sends to the PPS data notices containing data start and stop times along with a checksum for the file for each observatory data file transmitted. MPISS retrieves the PPS generated data receipts that indicate the success or failure of the PPS to ingest the data file and/or notice. MPISS retransmits the appropriate files as indicated in the receipt when required. MPISS also automatically retrieves files from the PPS. The unique feature of this software is the use of both standard and PPS specific protocols in parallel. The advantage of this capability is that it supports users that require the PPS protocol as well as those that do not require it. The system is highly configurable to accommodate the needs of future users.

INFECTION RETARDANT COATINGS IMPACT ON BACTERIAL PRESENCE IN PENILE PROSTHESIS SURGERY: A MULTICENTER STUDY.

PubMed

Jani, Kavina; Smith, Christopher; Delk, John R; Carson, Culley C; Donatucci, Craig F; Cleves, Mario A; Wilson, Steven K; Henry, Gerard D

2018-06-09

To investigate patients for positive culture rates with or without IRC PPs and to examine changes in culture positive isolates found in patients presenting overt clinical infection. Cultures were obtained from PPs immediately upon surgical exposure of the pump. 236 patients were broken down into 2 groups, with each further divided into 2 groups. The non-infected group included 208 patients: 133 with uncoated PPs and 75 with IRC implants. The infected group included 28 patients: 16 with uncoated PP and 12 with IRC IPP. Additionally, sensitivity to the combination of tetracycline and rifampin were evaluated on all cultures. In the non-infected group, culture positive isolates were found in 85 patients with uncoated PP's and in 32 patients with IRC implants [p-value = 0.0003]. Cultures positive for Staphylococcus genus were found in 75 uncoated PP patients, while 20 patients with IRC implants had an isolate of this genus. In the infected group, culture positive isolates were found in 7 patients with uncoated PP and 6 patients with IRC IPPs [p-value = 1.000]. Positive cultures for Staphylococcus genus were found in 6 patients with uncoated PP, while 3 patients with IRC IPP had an isolate of this genus. All bacterial isolates were sensitive to the combination of tetracycline and rifampin. Positive bacterial cultures have been shown to be present on clinically uninfected IPPs at time of revision surgery. Culture isolates grown from patients with IRC IPPs reveal a non-traditional bacterial profile: fewer cultured isolates of Staphylococcus genus. Copyright © 2018. Published by Elsevier Inc.

Initial home health outcomes under prospective payment.

PubMed

Schlenker, Robert E; Powell, Martha C; Goodrich, Glenn K

2005-02-01

To assess initial changes in home health patient outcomes under Medicare's home health Prospective Payment System (PPS), implemented by the Centers for Medicare and Medicaid Services (CMS) in October 2000. Pre-PPS and early PPS data were obtained from CMS Outcome and Assessment Information Set (OASIS) and Medicare claims files. Regression analysis was applied to national random samples (n=164,810) to estimate pre-PPS/PPS outcome and visit-per-episode changes. Outcome episodes were constructed from OASIS data and linked with Medicare claims data on visits. Outcome changes (risk adjusted) were mixed and generally modest. Favorable changes included higher improvement rates under PPS for functioning and dyspnea, higher community discharge rates, and lower hospitalization and emergent care rates. Most stabilization (nonworsening) outcome rates also increased. However, improvement rates were lower under PPS for wounds, incontinence, and cognitive and emotional/behavioral outcomes. Total visits per episode (case-mix adjusted) declined 16.6 percent although therapy visits increased by 8.4 percent. The outcome and visit results suggest improved system efficiency under PPS (fewer visits, similar outcomes). However, declines in several improvement rates merit ongoing monitoring, as do subsequent (posthome health) hospitalization and emergent care use. Since only the early PPS period was examined, longer-term analyses are needed.

Time-resolved measurements of black carbon light absorption enhancement in urban and near-urban locations of Southern Ontario, Canada

NASA Astrophysics Data System (ADS)

Chan, T. W.; Brook, J. R.; Smallwood, G. J.; Lu, G.

2010-08-01

In this study a photoacoustic spectrometer (PA), a laser-induced incandescence instrument system (LII) and an aerosol mass spectrometer were operated in parallel for in situ measurements of black carbon (BC) light absorption enhancement. Results of a thermodenuder experiment using ambient particles in Toronto are presented first to show that LII measurements of BC are not influenced by particle coating while the PA response is enhanced and also that the nature of this enhancement is influenced by particle morphology. Comparisons of ambient PA and LII measurements at four different locations (suburban Toronto; a street canyon with heavy diesel bus traffic in Ottawa; adjacent to a commuter highway in Ottawa and; regional background air in and around Windsor, Ontario), show that the different meteorological conditions and atmospheric processes result in different particle light absorption enhancement and hence the specific attenuation coefficient (SAC). Depending upon location of measurement and the BC spherule diameter (primary particle size - PPS) measurement from the LII, the SAC varies from 2.6±0.04 to 22.5±0.7 m2 g-1. Observations from this study also show the active surface area of the BC aggregate, inferred from PPS, is an important parameter for inferring the degree of particle collapse of a BC particle. The predictability of the overall BC light absorption enhancement in the atmosphere depends not only on the coating mass but also on the source of the BC and on our ability to predict or measure the change in particle morphology as particles evolve.

Identification of lipid-phosphatidylserine (PS) as the target of unbiasedly selected cancer specific peptide-peptoid hybrid PPS1.

PubMed

Desai, Tanvi J; Toombs, Jason E; Minna, John D; Brekken, Rolf A; Udugamasooriya, Damith Gomika

2016-05-24

Phosphatidylserine (PS) is an anionic phospholipid maintained on the inner-leaflet of the cell membrane and is externalized in malignant cells. We previously launched a careful unbiased selection targeting biomolecules (e.g. protein, lipid or carbohydrate) distinct to cancer cells by exploiting HCC4017 lung cancer and HBEC30KT normal epithelial cells derived from the same patient, identifying HCC4017 specific peptide-peptoid hybrid PPS1. In this current study, we identified PS as the target of PPS1. We validated direct PPS1 binding to PS using ELISA-like assays, lipid dot blot and liposome based binding assays. In addition, PPS1 recognized other negatively charged and cancer specific lipids such as phosphatidic acid, phosphatidylinositol and phosphatidylglycerol. PPS1 did not bind to neutral lipids such as phosphatidylethanolamine found in cancer and phosphatidylcholine and sphingomyelin found in normal cells. Further we found that the dimeric version of PPS1 (PPS1D1) displayed strong cytotoxicity towards lung cancer cell lines that externalize PS, but not normal cells. PPS1D1 showed potent single agent anti-tumor activity and enhanced the efficacy of docetaxel in mice bearing H460 lung cancer xenografts. Since PS and anionic phospholipid externalization is common across many cancer types, PPS1 may be an alternative to overcome limitations of protein targeted agents.

Microbiota-derived butyrate suppresses group 3 innate lymphoid cells in terminal ileal Peyer's patches.

PubMed

Kim, Sae-Hae; Cho, Byeol-Hee; Kiyono, Hiroshi; Jang, Yong-Suk

2017-06-21

The regional specialization of intestinal immune cells is affected by the longitudinal heterogeneity of environmental factors. Although the distribution of group 3 innate lymphoid cells (ILC3s) is well characterized in the lamina propria, it is poorly defined in Peyer's patches (PPs) along the intestine. Given that PP ILC3s are closely associated with mucosal immune regulation, it is important to characterize the regulatory mechanism of ILC3s. Here, we found that terminal ileal PPs of specific pathogen-free (SPF) mice have fewer NKp46 + ILC3s than jejunal PPs, while there was no difference in NKp46 + ILC3 numbers between terminal ileal and jejunal PPs in antibiotics (ABX)-treated mice. We also found that butyrate levels in the terminal ileal PPs of SPF mice were higher than those in the jejunal PPs of SPF mice and terminal ileal PPs of ABX-treated mice. The reduced number of NKp46 + ILC3s in terminal ileal PPs resulted in a decrease in Csf2 expression and, in turn, resulted in reduced regulatory T cells and enhanced antigen-specific T-cell proliferation. Thus, we suggest that NKp46 + ILC3s are negatively regulated by microbiota-derived butyrate in terminal ileal PPs and the reduced ILC3 frequency is closely associated with antigen-specific immune induction in terminal ileal PPs.

Quantitation of blood lymphocytes secreting antibodies to pneumococcal polysaccharides after in vivo antigenic stimulation.

PubMed

Heilmann, C; Pedersen, F K

1986-02-01

An indirect plaque-forming cell assay detecting B cells secreting IgM, IgG and IgA antibodies against pneumococcal polysaccharides (PPS) is described. The numbers of anti-PPS-secreting cells (SC) and Ig-SC in the blood of normal persons immunized with a polyvalent PPS vaccine were quantitated. Anti-PPS-SC were recorded from the fourth to the twelfth post-vaccination day, and the maximum number was found between days 6 and 9. Quantitatively IgA anti-PPS-SC outnumbered the IgM and IgG anti-PPS-SC. Concomitant with the increase in the numbers of antibody-SC an increase in polyclonally activated IgM-, IgG- and IgA-SC was recorded. The specific anti-PPS-antibody-SC constituted 20-80% of the total numbers of Ig-SC from the sixth to the ninth post-vaccination day.

Feasibility study of strengthening the public-private partnership for tuberculosis case detection in Bandung City, Indonesia.

PubMed

Lestari, Bony Wiem; Arisanti, Nita; Siregar, Adiatma Y M; Sihaloho, Estro Dariatno; Budiman, Gelar; Hill, Philip C; Alisjahbana, Bachti; McAllister, Susan

2017-08-14

Private practitioner's (PPs) collaboration for detection, diagnosis and treatment of tuberculosis (TB) is recommended by the World Health Organization and encouraged by the Indonesian National TB control programme. TB case management by PPs, however, are mostly not in line with current guidelines. Therefore, we developed an intervention package for PPs comprising of TB training, implementation of a mobile phone application for notification of TB cases and a 6-month regular follow-up with PPs. This study aimed to evaluate the feasibility of the intervention package to increase TB case detection and notification rates among PPs in five community health centre areas in Bandung City, Indonesia. A total of 87 PPs were registered within the study area of whom 17 attended the training and 12 had the mobile phone application successfully installed. The remaining five PPs had phones that did not support the application. During the follow-up period, five PPs registered patients with TB symptoms and cases into the application. A total of 36 patients with TB symptoms were identified and 17 were confirmed TB positive.

Spinal cord lesions shrink peripersonal space around the feet, passive mobilization of paraplegic limbs restores it.

PubMed

Scandola, Michele; Aglioti, Salvatore Maria; Bonente, Claudio; Avesani, Renato; Moro, Valentina

2016-04-06

Peripersonal space (PPS) is the space surrounding us within which we interact with objects. PPS may be modulated by actions (e.g. when using tools) or sense of ownership (e.g. over a rubber hand). Indeed, intense and/or prolonged use of a tool may induce a sense of ownership over it. Conversely, inducing ownership over a rubber hand may activate brain regions involved in motor control. However, the extent to which PPS is modulated by action-dependent or ownership-dependent mechanisms remains unclear. Here, we explored the PPS around the feet and the sense of ownership over lower limbs in people with Paraplegia following Complete spinal cord Lesions (PCL) and in healthy subjects. PCL people can move their upper body but have lost all sensory-motor functions in their lower body (e.g. lower limbs). We tested whether PPS alterations reflect the topographical representations of various body parts. We found that the PPS around the feet was impaired in PCL who however had a normal representation of the PPS around the hands. Significantly, passive mobilization of paraplegic limbs restored the PPS around the feet suggesting that activating action representations in PCL brings about short-term changes of PPS that may thus be more plastic than previously believed.

Spinal cord lesions shrink peripersonal space around the feet, passive mobilization of paraplegic limbs restores it

PubMed Central

Scandola, Michele; Aglioti, Salvatore Maria; Bonente, Claudio; Avesani, Renato; Moro, Valentina

2016-01-01

Peripersonal space (PPS) is the space surrounding us within which we interact with objects. PPS may be modulated by actions (e.g. when using tools) or sense of ownership (e.g. over a rubber hand). Indeed, intense and/or prolonged use of a tool may induce a sense of ownership over it. Conversely, inducing ownership over a rubber hand may activate brain regions involved in motor control. However, the extent to which PPS is modulated by action-dependent or ownership-dependent mechanisms remains unclear. Here, we explored the PPS around the feet and the sense of ownership over lower limbs in people with Paraplegia following Complete spinal cord Lesions (PCL) and in healthy subjects. PCL people can move their upper body but have lost all sensory-motor functions in their lower body (e.g. lower limbs). We tested whether PPS alterations reflect the topographical representations of various body parts. We found that the PPS around the feet was impaired in PCL who however had a normal representation of the PPS around the hands. Significantly, passive mobilization of paraplegic limbs restored the PPS around the feet suggesting that activating action representations in PCL brings about short-term changes of PPS that may thus be more plastic than previously believed. PMID:27049439

Frequency and outcomes of painful physical symptoms in a naturalistic population with major depressive disorder: an analysis of pooled observational studies focusing on subjects aged 65 years and over.

PubMed

Brnabic, A; Raskin, J; Alev, L; Serap Monkul, E; Lowry, A

2012-12-01

To estimate the frequency of painful physical symptoms (PPS) in elderly subjects (≥ 65 years) with major depressive disorder (MDD) in real-world clinical conditions and to establish whether PPS are associated with poor depression outcomes, including more severe depression and worse health-related quality of life (HRQoL). Observational studies of MDD that included assessment of PPS and elderly subjects were screened. Measures of PPS were based on the Somatic Symptom Inventory (SSI) or Visual Analogue Scale (VAS). Data from a variety of depressive symptom severity and HRQoL scales were used. Analysis cohorts were based on age [aged ≥ 65 years (elderly) or < 65 years (younger)] and/or PPS status (presence or absence); five subsets were used to examine specific outcomes in matched elderly subjects. Data from seven studies (representing 26 countries) were collated. Of the 11,477 subjects, 14% were aged ≥ 65 years and 71% were classified as having PPS (PPS+). PPS were more frequent in elderly subjects (74% vs. 70% of younger subjects) and were positively associated with being female and Hispanic, and negatively associated with being East Asian in the elderly. The presence of PPS was associated with more severe clinical symptomatology and comparatively poorer HRQoL in elderly subjects. PPS, although frequent in younger MDD patients, were slightly more frequent in elderly MDD patients and associated with comparatively poorer clinical and functional outcomes. As elderly patients report somatic symptoms more readily than emotional symptoms, physicians should consider depression in addition to physical causes when PPS are present. © 2012 Blackwell Publishing Ltd.

Extending peripersonal space representation without tool-use: evidence from a combined behavioral-computational approach

PubMed Central

Serino, Andrea; Canzoneri, Elisa; Marzolla, Marilena; di Pellegrino, Giuseppe; Magosso, Elisa

2015-01-01

Stimuli from different sensory modalities occurring on or close to the body are integrated in a multisensory representation of the space surrounding the body, i.e., peripersonal space (PPS). PPS dynamically modifies depending on experience, e.g., it extends after using a tool to reach far objects. However, the neural mechanism underlying PPS plasticity after tool use is largely unknown. Here we use a combined computational-behavioral approach to propose and test a possible mechanism accounting for PPS extension. We first present a neural network model simulating audio-tactile representation in the PPS around one hand. Simulation experiments showed that our model reproduced the main property of PPS neurons, i.e., selective multisensory response for stimuli occurring close to the hand. We used the neural network model to simulate the effects of a tool-use training. In terms of sensory inputs, tool use was conceptualized as a concurrent tactile stimulation from the hand, due to holding the tool, and an auditory stimulation from the far space, due to tool-mediated action. Results showed that after exposure to those inputs, PPS neurons responded also to multisensory stimuli far from the hand. The model thus suggests that synchronous pairing of tactile hand stimulation and auditory stimulation from the far space is sufficient to extend PPS, such as after tool-use. Such prediction was confirmed by a behavioral experiment, where we used an audio-tactile interaction paradigm to measure the boundaries of PPS representation. We found that PPS extended after synchronous tactile-hand stimulation and auditory-far stimulation in a group of healthy volunteers. Control experiments both in simulation and behavioral settings showed that the same amount of tactile and auditory inputs administered out of synchrony did not change PPS representation. We conclude by proposing a simple, biological-plausible model to explain plasticity in PPS representation after tool-use, which is supported by computational and behavioral data. PMID:25698947

Extending peripersonal space representation without tool-use: evidence from a combined behavioral-computational approach.

PubMed

Serino, Andrea; Canzoneri, Elisa; Marzolla, Marilena; di Pellegrino, Giuseppe; Magosso, Elisa

2015-01-01

Stimuli from different sensory modalities occurring on or close to the body are integrated in a multisensory representation of the space surrounding the body, i.e., peripersonal space (PPS). PPS dynamically modifies depending on experience, e.g., it extends after using a tool to reach far objects. However, the neural mechanism underlying PPS plasticity after tool use is largely unknown. Here we use a combined computational-behavioral approach to propose and test a possible mechanism accounting for PPS extension. We first present a neural network model simulating audio-tactile representation in the PPS around one hand. Simulation experiments showed that our model reproduced the main property of PPS neurons, i.e., selective multisensory response for stimuli occurring close to the hand. We used the neural network model to simulate the effects of a tool-use training. In terms of sensory inputs, tool use was conceptualized as a concurrent tactile stimulation from the hand, due to holding the tool, and an auditory stimulation from the far space, due to tool-mediated action. Results showed that after exposure to those inputs, PPS neurons responded also to multisensory stimuli far from the hand. The model thus suggests that synchronous pairing of tactile hand stimulation and auditory stimulation from the far space is sufficient to extend PPS, such as after tool-use. Such prediction was confirmed by a behavioral experiment, where we used an audio-tactile interaction paradigm to measure the boundaries of PPS representation. We found that PPS extended after synchronous tactile-hand stimulation and auditory-far stimulation in a group of healthy volunteers. Control experiments both in simulation and behavioral settings showed that the same amount of tactile and auditory inputs administered out of synchrony did not change PPS representation. We conclude by proposing a simple, biological-plausible model to explain plasticity in PPS representation after tool-use, which is supported by computational and behavioral data.

Neural adaptation accounts for the dynamic resizing of peripersonal space: evidence from a psychophysical-computational approach.

PubMed

Noel, Jean-Paul; Blanke, Olaf; Magosso, Elisa; Serino, Andrea

2018-06-01

Interactions between the body and the environment occur within the peripersonal space (PPS), the space immediately surrounding the body. The PPS is encoded by multisensory (audio-tactile, visual-tactile) neurons that possess receptive fields (RFs) anchored on the body and restricted in depth. The extension in depth of PPS neurons' RFs has been documented to change dynamically as a function of the velocity of incoming stimuli, but the underlying neural mechanisms are still unknown. Here, by integrating a psychophysical approach with neural network modeling, we propose a mechanistic explanation behind this inherent dynamic property of PPS. We psychophysically mapped the size of participant's peri-face and peri-trunk space as a function of the velocity of task-irrelevant approaching auditory stimuli. Findings indicated that the peri-trunk space was larger than the peri-face space, and, importantly, as for the neurophysiological delineation of RFs, both of these representations enlarged as the velocity of incoming sound increased. We propose a neural network model to mechanistically interpret these findings: the network includes reciprocal connections between unisensory areas and higher order multisensory neurons, and it implements neural adaptation to persistent stimulation as a mechanism sensitive to stimulus velocity. The network was capable of replicating the behavioral observations of PPS size remapping and relates behavioral proxies of PPS size to neurophysiological measures of multisensory neurons' RF size. We propose that a biologically plausible neural adaptation mechanism embedded within the network encoding for PPS can be responsible for the dynamic alterations in PPS size as a function of the velocity of incoming stimuli. NEW & NOTEWORTHY Interactions between body and environment occur within the peripersonal space (PPS). PPS neurons are highly dynamic, adapting online as a function of body-object interactions. The mechanistic underpinning PPS dynamic properties are unexplained. We demonstrate with a psychophysical approach that PPS enlarges as incoming stimulus velocity increases, efficiently preventing contacts with faster approaching objects. We present a neurocomputational model of multisensory PPS implementing neural adaptation to persistent stimulation to propose a neurophysiological mechanism underlying this effect.

Influence of the forming process on the mechanical behavior of a commingled carbon PPS composite part

NASA Astrophysics Data System (ADS)

Patou, J.; De Luycker, E.; Bonnaire, R.; Cutard, T.; Bernhart, G.

2018-05-01

In this research work, the influence of the forming process on commingled thermoplastic composite parts mechanical behavior was investigated. The aim of this work is to evaluate the influence of fabric shearing on the mechanical response of composite laminate. Different sheets with a given shear angle are manufactured. Tensile experimental results are compared with the properties obtained from a simple model based on the laminate plate theory for various off angles. Later, the link with a tetrahedron shape 3D part manufactured by punch deep drawing will be made.

Pressure pain sensitivity as a marker for stress and pressure pain sensitivity-guided stress management in women with primary breast cancer.

PubMed

Axelsson, Christen K; Ballegaard, Søren; Karpatschof, Benny; Schousen, Peer

2014-08-01

To validate (1) Pressure Pain Sensitivity (PPS) as a marker for stress and (2) a PPS-guided intervention in women with primary Breast Cancer (BC). (1) A total of 58 women with BC were examined before and after 6 months of intervention. A control group of 165 women office employees was divided in a High Stress Group (HSG, n = 37) and a Low Stress Group (LSG, n = 128) to evaluate the association between PPS, questionnaire-related Quality of Life (QOL) and self-evaluated stress. (2) A PPS-guided stress management program (n = 40) was compared to a Psychosocial Group Intervention (PGI, n = 91) and no treatment (n = 86) with respect to a European Organization for Research and Treatment of Cancer (EORTC) questionnaire measured QOL. (1) Resting PPS and changes in PPS during the intervention period correlated significantly to EORTC and Short Form 36 (SF 36) main scores: (all p < 0.05). Between BC, HSG and LSG there was a significant and positive correlation with respect to PPS, SF 36 main scores, depression, and clinical stress scores (all p < 0.05). However, the BC group scored significantly lower than both HSG and LSG (both p < 0.05) with respect to self-evaluated stress. (2) The PPS-guided intervention group improved EORTC main score, pain and nausea, when compared to the control groups (all p < 0.05). PPS was positively associated with QOL, which was in contrast to self-evaluated stress. PPS-guided intervention improved QOL in women with breast cancer.

Rehabilitation services after the implementation of the nursing home prospective payment system: differences related to patient and nursing home characteristics.

PubMed

Murray, Patrick K; Love, Thomas E; Dawson, Neal V; Thomas, Charles L; Cebul, Randall D

2005-11-01

The prospective payment system (PPS) for nursing homes was designed to curtail the rapid expansion of Medicare costs for skilled nursing care. This study examines the changes that occurred in nursing home patients and rehabilitation services following the PPS. Free-standing Medicare and/or Medicaid certified nursing homes in Ohio. The percent of new admissions receiving therapy and the amount of rehabilitation therapy provided. A total of 7006 first admissions in 1994-6 (pre-PPS) and 61,569 first admissions in 2000-1 (post-PPS). A logistic model predicting likelihood of rehabilitation was developed and validated in pre-PPS admissions and applied to the post-PPS patients. Rehabilitation services were compared in the pre-PPS and post-PPS cohorts overall, stratified by quintile of predicted score, diagnosis group, and by nursing home profit status. Post-PPS patients had less cognitive impairment, more depression, and more family support. The amount of rehabilitation services declined the most in the higher quintiles of predicted likelihood of rehabilitation and among patients with stroke. The percent of patients receiving rehabilitation services increased the most in the lowest quintile and among patients with medical conditions. These changes were greater in for-profit nursing homes. The implementation of the PPS in nursing homes has been associated with a decrease in the amount of rehabilitation services, targeted at those predicted to receive higher amounts and an increased frequency of providing services targeted at those predicted to be less likely to receive them. The outcomes of the changes deserve further study.

Phosphorylation of psyllium seed polysaccharide and its characterization.

PubMed

Rao, Monica R P; Warrier, Deepa U; Gaikwad, Snehal R; Shevate, Prachi M

2016-04-01

Psyllium is widely used as a medicinally active natural polysaccharide for treating conditions like constipation, diarrhea, and irritable bowel syndrome, inflammatory bowel disease, ulcerative colitis and colon cancer. Studies have been performed to characterize and modify the polysaccharide obtained from psyllium seed husk and to evaluate its use as a pharmaceutical excipient, but no studies have been performed to evaluate the properties of the polysaccharide present in psyllium seeds. The present study focuses on phosphorylation of psyllium seed polysaccharide (PPS) using sodium tri-meta phosphate as the cross-linking agent. The modified phosphorylated psyllium seed polysaccharide was then evaluated for physicochemical properties, rheological properties, spectral analysis, thermal analysis, crosslinking density and acute oral toxicity studies. The modified polysaccharide (PhPPS) has a high swelling index due to which it can be categorized as a hydrogel. The percent increase in swelling of PhPPS as compared to PPS was found to be 90.26%. The PPS & PhPPS mucilages of all strengths were found to have shear thinning properties. These findings are suggestive of the potential use of PhPPS as gelling & suspending agent. PhPPS was found to have a mucoadhesive property which was comparable with carbopol. Copyright © 2015 Elsevier B.V. All rights reserved.

Neuropathic pain in post-burn hypertrophic scars: a psychophysical and neurophysiological study.

PubMed

Isoardo, Gianluca; Stella, Maurizio; Cocito, Dario; Risso, Daniela; Migliaretti, Giuseppe; Cauda, Franco; Palmitessa, Angela; Faccani, Giuliano; Ciaramitaro, Palma

2012-06-01

Pain complicates hypertrophic post-burn pathologic scars (PPS) METHODS: To investigate the possible neuropathic origin of pain, 13 patients with painful PPS involving at least 1 hand underwent clinical examination, including the Douleur Neuropathique en 4 questions (DN4) questionnaire; median, ulnar, and radial nerve conduction studies (NCS); cold- (CDT) and heat-induced pain threshold evaluation by quantitative sensory testing; and cutaneous silent period (CSP) testing of the abductor pollicis brevis. Controls included 9 patients with non-painful PPS, 52 healthy subjects, and 28 patients with carpal tunnel syndrome (CTS). All patients with painful PPS had possible neuropathic pain (DN4 score ≥4). NCS signs of CTS were similarly present in PPS subjects with or without pain. Hands with painful PPS had lower CDT and CSP duration, more frequent cold- and heat-pain hypesthesia, and more thermal allodynia than controls. In PPS, possible neuropathic pain is associated with psychophysical and neurophysiological abnormalities suggestive of small-fiber damage. Copyright © 2011 Wiley Periodicals, Inc.

Ionic electrodeposition of II-VI and III-V compounds. III. Computer simulation of quasi-rest potentials for M/sub 1/X/sub 1/ compounds analogous to CdTe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engelken, R.D.

1987-04-01

The quasi-rest potential (QRP) has been proposed as a key quantity in characterizing compound semiconductor (e.g. CdTe) electrodeposition. This article expands the modeling/simulation representative of Cd/sub x/Te in chemical equilibrium to calculate two ''QRP's'': E/sub M/1/sub /, the mixed potential occurring immediately after current interruption and before any relaxation in double layer ion concentration and significant ion exchange/surface stoichiometry change occur, and E/sub M/2/sub /, another mixed potential occurring after the double layer ion concentrations have relaxed to their bulk values but still before any significant surface composition change occurs. Significant predictions include existence of a dramatic negative transition inmore » QRP, with negative-going deposition potential, centered on the potential of perfect stoichiometry (PPS), inequality, in general, between the PPS and E/sub M/1/sub / unless the deposit remains in equilibrium with the electrolyte (no ion exchange at open circuit), negligible sensitivity of QRP-E curves to the activity coefficient parameter implying the importance of the PPS in characterizing compound deposition, and disappearance of the transition structure for sufficiently positive Gibbs free energies.« less

Development and performance of power processor system for 2-gigahertz, 200-watt amplifier for communications technology satellite

NASA Technical Reports Server (NTRS)

Siegert, C. E.; Gourash, F.; Vasicek, R. W.

1977-01-01

The electrical and environmental requirements for a power processor system (PPS) designed to supply the appropriate voltages and currents to a 200-watt traveling wave tube (TWT) for a communication technology satellite is described. A block diagram of the PPS, the interface requirements between the PPS and spacecraft, the interface requirements between the PPS and 200-watt TWT, and the environmental requirements of the PPS are presented. Also included are discussions of protection circuits, interlocking sequences, and transient requirements. Predictions of the flight performance, based on ground test data, are provided.

Performance of freestanding inpatient rehabilitation hospitals before and after the rehabilitation prospective payment system.

PubMed

Thompson, Jon M; McCue, Michael J

2010-01-01

Inpatient rehabilitation hospitals provide important services to patients to restore physical and cognitive functioning. Historically, these hospitals have been reimbursed by Medicare under a cost-based system; but in 2002, Medicare implemented a rehabilitation prospective payment system (PPS). Despite the implementation of a PPS for rehabilitation, there is limited published research that addresses the operating and financial performance of these hospitals. We examined operating and financial performance in the pre- and post-PPS periods for for-profit and nonprofit freestanding inpatient rehabilitation hospitals to test for pre- and post-PPS differences within the ownership groups. We identified freestanding inpatient rehabilitation hospitals from the Centers for Medicare and Medicaid Services Health Care Cost Report Information System database for the first two fiscal years under PPS. We excluded facilities that had fiscal years less than 270 days, facilities with missing data, and government facilities. We computed average values for performance variables for the facilities in the two consecutive fiscal years post-PPS. For the pre-PPS period, we collected data on these same facilities and, once facilities with missing data and fiscal years less than 270 days were excluded, computed average values for the two consecutive fiscal years pre-PPS. Our final sample of 140 inpatient rehabilitation facilities was composed of 44 nonprofit hospitals and 96 for-profit hospitals both pre- and post-PPS. We utilized a pairwise comparison test (t-test comparison) to measure the significance of differences on each performance variable between pre- and post-PPS periods within each ownership group. Findings show that both nonprofit and for-profit freestanding inpatient rehabilitation hospitals reduced length of stay, increased discharges, and increased profitability. Within the for-profit ownership group, the percentage of Medicare discharges increased and operating expense per adjusted discharge decreased. Findings suggest that managers of these hospitals have adapted their administrative practices to conform with the financial incentives of the rehabilitation PPS. Managers must continue to control costs, increase discharges, and reduce length of stay to remain financially viable under the rehabilitation PPS.

Preparation of Plasmonic Platforms of Silver Wires on Gold Mirrors and Their Application to Surface Enhanced Fluorescence

PubMed Central

2015-01-01

In this report we describe a preparation of silver wires (SWs) on gold mirrors and its application to surface enhanced fluorescence (SEF) using a new methodology. Silica protected gold mirrors were drop-coated with a solution of silver triangular nanoprisms. The triangular nanoprisms were slowly air-dried to get silver wires that self-assembled on the gold mirrors. Fluorescence enhancement was studied using methyl azadioxatriangulenium chloride (Me-ADOTA·Cl) dye in PVA spin-coated on a clean glass coverslip. New Plasmonic Platforms (PPs) were assembled by placing a mirror with SWs in contact with a glass coverslip spin-coated with a uniform Me-ADOTA·Cl film. It was shown that surface enhanced fluorescence is a real phenomenon, not just an enhancement of the fluorescence signal due to an accumulation of the fluorophore on rough nanostructure surfaces. The average fluorescence enhancement was found to be about 15-fold. The lifetime of Me-ADOTA·Cl dye was significantly reduced (∼4 times) in the presence of SWs. Moreover, fluorescence enhancement and lifetime did not show any dependence on the excitation light polarization. PMID:25296293

Pentosan polysulfate inhibits atherosclerosis in Watanabe heritable hyperlipidemic rabbits: differential modulation of metalloproteinase-2 and -9.

PubMed

Lupia, Enrico; Zheng, Feng; Grosjean, Fabrizio; Tack, Ivan; Doublier, Sophie; Elliot, Sharon J; Vlassara, Helen; Striker, Gary E

2012-02-01

Pentosan polysulfate (PPS), a heparinoid compound essentially devoid of anticoagulant activity, modulates cell growth and decreases inflammation. We investigated the effect of PPS on the progression of established atherosclerosis in Watanabe heritable hyperlipidemic (WHHL) rabbits. After severe atherosclerosis developed on an atherogenic diet, WHHL rabbits were treated with oral PPS or tap water for 1 month. The aortic intima-to-media ratio and macrophage infiltration were reduced, plaque collagen content was increased, and plaque fibrous caps were preserved by PPS treatment. Plasma lipid levels and post-heparin hepatic lipase activity remained unchanged. However, net collagenolytic activity in aortic extracts was decreased, and the levels of matrix metalloproteinase (MMP)-2 and tissue inhibitor of metalloproteinase (TIMP) activity were increased by PPS. Moreover, PPS treatment decreased tumor necrosis factor α (TNFα)-stimulated proinflammatory responses, in particular activation of nuclear factor-κB and p38, and activation of MMPs in macrophages. In conclusion, oral PPS treatment prevents progression of established atherosclerosis in WHHL rabbits. This effect may be partially mediated by increased MMP-2 and TIMP activities in the aortic wall and reduced TNFα-stimulated inflammation and MMP activation in macrophages. Thus, PPS may be a useful agent in inhibiting the progression of atherosclerosis.

Pentosan polysulfate inhibits atherosclerosis in Watanabe heritable hyperlipidemic rabbits: differential modulation of metalloproteinase-2 and -9

PubMed Central

Lupia, Enrico; Zheng, Feng; Grosjean, Fabrizio; Tack, Ivan; Doublier, Sophie; Elliot, Sharon J; Vlassara, Helen; Striker, Gary E

2013-01-01

Pentosan polysulfate (PPS), a heparinoid compound essentially devoid of anticoagulant activity, modulates cell growth and decreases inflammation. We investigated the effect of PPS on the progression of established atherosclerosis in Watanabe heritable hyperlipidemic (WHHL) rabbits. After severe atherosclerosis developed on an atherogenic diet, WHHL rabbits were treated with oral PPS or tap water for 1 month. The aortic intima-to-media ratio and macrophage infiltration were reduced, plaque collagen content was increased, and plaque fibrous caps were preserved by PPS treatment. Plasma lipid levels and post-heparin hepatic lipase activity remained unchanged. However, net collagenolytic activity in aortic extracts was decreased, and the levels of matrix metalloproteinase (MMP)-2 and tissue inhibitor of metalloproteinase (TIMP) activity were increased by PPS. Moreover, PPS treatment decreased tumor necrosis factor α (TNFα)-stimulated proinflammatory responses, in particular activation of nuclear factor-κB and p38, and activation of MMPs in macrophages. In conclusion, oral PPS treatment prevents progression of established atherosclerosis in WHHL rabbits. This effect may be partially mediated by increased MMP-2 and TIMP activities in the aortic wall and reduced TNFα-stimulated inflammation and MMP activation in macrophages. Thus, PPS may be a useful agent in inhibiting the progression of atherosclerosis. PMID:22042083

An automated technique for manufacturing thermoplastic stringers in continuous length

NASA Astrophysics Data System (ADS)

Pantelakis, Sp.; Baxevani, E.; Spelz, U.

In the present work an automated Continuous Compression Moulding Technique for the manufacture of stringers in continuous length is presented. The method combines pultrusion and hot-pressing. The technique is utilized for the production of L-shape stringers which are widely applied in aerospace constructions. The investigation was carried out on carbon reinforced PEEK (C/PEEK), as well as, for comparison, on the thermoplastic composites carbon reinforced polyethersulfon (C/PES), glass and carbon reinforced polyphenylene-sulfide (G/PPS, C/PPS) and Kevlar reinforced Polyamide 6 (K/PA 6). For the materials investigated the optimized process parameters for manufacturing the L-shape stringers were derived experimentally. To achieve this goal, the quality of the produced parts was controlled by using non-destructive testing techniques. Parts providing satisfactory quality were also tested destructively to measure their mechanical properties. The investigation results have shown the suitability of the technique to produce continuous length stringers.

PpsA-mediated alternative pathway to complement RNase E essentiality in Escherichia coli.

PubMed

Tamura, Masaru; Honda, Naoko; Fujimoto, Hirofumi; Cohen, Stanley N; Kato, Atsushi

2016-07-01

Escherichia coli cells require RNase E, encoded by the essential gene rne, to propagate. The growth properties on different carbon sources of E. coli cells undergoing suppression of RNase E production suggested that reduction in RNase E is associated with decreased expression of phosphoenolpyruvate synthetase (PpsA), which converts pyruvate to phosphoenolpyruvate during gluconeogenesis. Western blotting and genetic complementation confirmed the role of RNase E in PpsA expression. Adventitious ppsA overexpression from a multicopy plasmid was sufficient to restore colony formation of ∆rne E. coli on minimal media containing glycerol or succinate as the sole carbon source. Complementation of ∆rne by ppsA overproduction was observed during growth on solid media but was only partial, and bacteria showed slowed cell division and grew as filamentous chains. We found that restoration of colony-forming ability by ppsA complementation occurred independent of the presence of endogenous RNase G or second-site suppressors of RNase E essentiality. Our investigations demonstrate the role of phosphoryl transfer catalyzable by PpsA as a determinant of RNase E essentiality in E. coli.

Impact of the new payment system on laparoscopic appendectomy in Korea.

PubMed

Kim, Jong Wan; Shin, Dong Woo; Chae, Jin Ju; Kim, Jeong Yeon; Park, Sung Gil

2015-12-01

Korea has a nationalized health system. The aim of this study was to evaluate the impact of the Korea diagnosis related group-based prospective payment system (K-DRG/PPS) on the use of medical resources and the rate of adverse events during laparoscopic appendectomy. We included patients who underwent laparoscopic appendectomy at Dongtan Sacred Heart Hospital, Korea, between November 2012 and February 2014. The patients were divided into two groups: before-DRG/PPS or after-DRG/PPS groups. The length of the postoperative hospital stay (LOS) and medical costs were indicators of the medical resources. Medical costs included those of the initial hospital stay, outpatient clinic, readmission, and the sum of these charges. Complication and readmission rates were indicators of the rates of adverse events. After the implementation of the DRG/PPS, length of the hospital stay decreased by 10% (4.9 d before versus 4.4 d after DRG/PPS; P < 0.001). The initial hospital stay and total cost were significantly lower in the after-DRG/PPS group (both P < 0.001). The complication rates during the initial hospital stay (3.5% before versus 2.3% after DRG/PPS; P = 0.225) and the readmission rates (4.3% versus 2.5%, respectively; P = 0.227) were statistically similar. This study shows that the K-DRG/PPS for laparoscopic appendectomy had no negative effect on the rate of adverse events and reduced the use of medical resources. Further evaluation of other procedures is required to determine the overall effects of the K-DRG/PPS. Copyright © 2015 Elsevier Inc. All rights reserved.

Identification of the minimum pharmacophore of lipid-phosphatidylserine (PS) binding peptide-peptoid hybrid PPS1D1.

PubMed

Singh, Jaspal; Shukla, Satya Prakash; Desai, Tanvi J; Udugamasooriya, D Gomika

2016-09-15

We previously reported a unique peptide-peptoid hybrid, PPS1 that specifically recognizes lipid-phosphatidylserine (PS) and a few other negatively charged phospholipids, but not neutral phospholipids, on the cell membrane. The dimeric version of PPS1, i.e., PPS1D1 triggers strong cancer cell cytotoxicity and has been validated in lung cancer models both in vitro and in vivo. Given that PS and other negatively charged phospholipids are abundant in almost all tumor microenvironments, PPS1D1 is an attractive drug lead that can be developed into a globally applicable anti-cancer agent. Therefore, it is extremely important to identify the minimum pharmacophore of PPS1D1. In this study, we have synthesized alanine/sarcosine derivatives as well as truncated derivatives of PPS1D1. We performed ELISA-like competitive binding assay to evaluate the PS-recognition potential and standard MTS cell viability assay on HCC4017 lung cancer cells to validate the cell cytotoxicity effects of these derivatives. Our studies indicate that positively charged residues at the second and third positions, as well as four hydrophobic residues at the fifth through eighth positions, are imperative for the binding and activity of PPS1D1. Methionine at the first position was not essential, whereas the positively charged Nlys at the fourth position was minimally needed, as two derivatives that were synthesized replacing this residue were almost as active as PPS1D1. Copyright © 2016 Elsevier Ltd. All rights reserved.

GM1 antibodies in post-polio syndrome and previous paralytic polio.

PubMed

Farbu, E; Rekand, T; Tysnes, O-B; Aarli, J A; Gilhus, N E; Vedeler, C A

2003-06-01

We studied the relationship between post-polio syndrome (PPS) and GM1 antibodies, since such antibodies have been associated with PPS and motor neuron disorders. Sera from 144 patients with previous poliomyelitis (105 paralytic, 22 nonparalytic and 17 PPS), 60 with previous Guillain-Barré syndrome, 44 with amyotrophic lateral sclerosis (ALS) and 22 healthy blood donors were analyzed with ELISA for GM1 IgM, IgG and IgA antibodies. GM1 antibodies were present in 14% of the PPS patients, but the prevalence did not differ significantly from that of the other groups. Our study does not support the hypothesis that GM1 antibodies are involved in the pathogenesis of PPS.

Microstructure evolution and mechanical properties of TiCN-Cr nano/micro composite coatings prepared by reactive plasma spraying

NASA Astrophysics Data System (ADS)

Zhang, Fanyong; He, Jining; Chen, Kai; Qin, Yanfang; Li, Chao; Yin, Fuxing

2018-01-01

Nanostructured TiCN based composite coatings with various Cr content were prepared by reactive plasma spray (RPS) from mixed powder (Ti-graphite + Cr) under nitrogen atmosphere. Results showed that composite coatings consisted mainly of TiC0.7N0.3 phase and residual metal Cr. Metal Cr plates were homogeneously embedded in TiCN matrix with good interface bond. The TiCN-Cr composite coatings exhibited lower porosity than TiCN coatings, but increasing porosity with excess Cr addition (30 wt.%). The TiCN-20 wt.% Cr coating showed the highest hardness (1309 HV0.2) among composite coatings, slight lower than the TiCN matrix coating (1526 HV0.2). Compared with the TiCN matrix coating, the TiCN-Cr composite coatings showed higher variability in surface microhardness distribution. The TiCN-Cr composite coatings showed slight higher friction coefficients (0.4-0.6) than TiCN matrix coating (0.35). The wear resistance of TiCN-Cr composite coatings was improved with less mass loss compared with TiCN coating under the test load of 400 N. The TiCN-Cr composite coatings with high Cr content showed the mixture of abrasive and adhesive wear.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, Yan-Xiang, E-mail: yxgong@sina.com

A hydrodynamical simulation shows that a circumbinary planet will migrate inward to the edge of the disk cavity. If multiple planets form in a circumbinary disk, successive migration will lead to planet–planet scattering (PPS). PPS of Kepler -like circumbinary planets is discussed in this paper. The aim of this paper is to answer how PPS affects the formation of these planets. We find that a close binary has a significant influence on the scattering process. If PPS occurs near the unstable boundary of a binary, about 10% of the systems can be completely destroyed after PPS. In more than 90%more » of the systems, there is only one planet left. Unlike the eccentricity distribution produced by PPS in a single star system, the surviving planets generally have low eccentricities if PPS take place near the location of the currently found circumbinary planets. In addition, the ejected planets are generally the innermost of two initial planets. The above results depend on the initial positions of the two planets. If the initial positions of the planets are moved away from the binary, the evolution tends toward statistics similar to those around single stars. In this process, the competition between the planet–planet force and the planet-binary force makes the eccentricity distribution of surviving planets diverse. These new features of P-type PPS will deepen our understanding of the formation of these circumbinary planets.« less

Exploring the role of organizational policies and procedures in promoting research utilization in registered nurses

PubMed Central

Squires, Janet E; Moralejo, Donna; LeFort, Sandra M

2007-01-01

Background Policies and procedures (P&Ps) have been suggested as one possible strategy for moving research evidence into practice among nursing staff in hospitals. Research in the area of P&Ps is limited, however. This paper explores: 1) nurses' use of eight specific research-based practices (RBPs) and RBP overall, 2) nurses' use and understanding of P&Ps, and 3) the role of P&Ps in promoting research utilization. Methods Staff nurses from the eight health regions governing acute care services across the Canadian province of Newfoundland and Labrador completed an anonymous questionnaire regarding their use of eight RBPs and associated P&Ps. Data were also obtained from authorities in six of the eight regions about existing relevant P&Ps. We used descriptive statistics and multivariate regression analysis to assess the relationship between key independent variables and self-reported use of RBP. Results Use of the eight RBPs ranged from 7.8% to 88.6%, depending on the practice. Nurses ranked P&P manuals as their number one source of practice knowledge. Most respondents (84.8%) reported that the main reason they consult the P&P manual is to confirm they are practicing according to agency rules. Multivariate regression analysis identified three significant predictors of being a user versus non-user of RBP overall: awareness, awareness by regular use, and persuasion. Six significant predictors of being a consistent versus less consistent user of RBP overall were also identified: perception of P&P existence, unit, nursing experience, personal experience as a source of practice knowledge, number of existing research-based P&Ps, and lack of time as a barrier to consulting P&P manuals. Conclusion Findings suggest that nurses use P&Ps to guide their practice. However, the mere existence of P&Ps is not sufficient to translate research into nursing practice. Individual and organizational factors related to nurses' understanding and use of P&Ps also play key roles. Thus, moving research evidence into practice will require careful interplay between the organization and the individual. P&Ps may be the interface through which this occurs. PMID:17550597

Gait characteristics of post-poliomyelitis patients: standardization of quantitative data reporting.

PubMed

Portnoy, S; Schwartz, I

2013-10-01

To evaluate the differences in gait characteristics and gait symmetry of post-polio syndrome (PPS) patients ambulating with or without shoes and between subgroups walking with different walking aids and orthoses, study the correlation of these data with personal data, illness condition, physical health, frequency of using aids and orthotics and frequency of falls, and derive recommendations for standardization of reporting these data. Twenty-six PPS subjects ambulated with their own walking devices. We calculated spatio-temporal parameters and symmetry indices (SI) of gait using a data acquired by a motion capture system. We compared inter-subject differences in gait pattern for PPS groups that differed by questionnaire-obtained data of demographics, physical activity, polio history, falls and walking aids. Additional inter-subject comparisons were performed between normal subjects (n=16), PPS patients walking with shoes with/without an ankle-foot-orthosis (n=11), PPS patients walking with knee-ankle-foot-orthosis (n=5), and PPS patients walking with a walker/crutches (n=10). We also compared intra-subject variability in PPS subjects who were able to repeat the trials barefoot. Our main results show that subjects who reported participating in physical activity twice a week or more had significantly better step time and double support symmetry. Subjects who use walking aids on a daily basis had significantly higher gait cadence and shorter stride time. Also, subjects that do not require knee-ankle-foot orthoses and/or walking aids walked with a smaller base width and better symmetry in stance and swing durations than PPS subjects who require these aids. The gait pattern of PPS patients is related to numerous intrinsic and extrinsic factors. Standardization of the reporting protocol of gait-related data of PPS patients is crucial for patient evaluation and treatment design. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Private Practitioners’ Perspectives on Their Involvement With the Tuberculosis Control Programme in a Southern Indian State

PubMed Central

Salve, Solomon; Sheikh, Kabir; Porter, John DH

2016-01-01

Background: Public and private health sectors both play a crucial role in the health systems of low- and middle-income countries (LMICs). The tuberculosis (TB) control strategy in India encourages the public sector to actively partner with private practitioners (PPs) to improve the quality of front line service delivery. However, ensuring effective and sustainable involvement of PPs constitutes a major challenge. This paper reports the findings from an empirical study focusing on the perspectives and experiences of PPs towards their involvement in TB control programme in India. Methods: The study was carried out between November 2010 and December 2011 in a district of a Southern Indian State and utilised qualitative methodologies, combining observations and in-depth interviews with 21 PPs from different medical systems. The collected data was coded and analysed using thematic analysis. Results: PPs perceived themselves to be crucial healthcare providers, with different roles within the public-private mix (PPM) TB policy. Despite this, PPs felt neglected and undervalued in the actual process of implementation of the PPM-TB policy. The entire process was considered to be government driven and their professional skills and knowledge of different medical systems remained unrecognised at the policy level, and weakened their relationship and bond with the policy and with the programme. PPs had contrasting perceptions about the different components of the TB programme that demonstrated the public sector’s dominance in the overall implementation of the DOTS strategy. Although PPs felt responsible for their TB patients, they found it difficult to perceive themselves as ‘partners with the TB programme.’ Conclusion: Public-private partnerships (PPPs) are increasingly utilized as a public health strategy to strengthen health systems. These policies will fail if the concerns of the PPs are neglected. To ensure their long-term involvement in the programme the abilities of PPs and the important perspectives from other Indian medical systems need to be recognised and supported. PMID:27801358

EKPD: a hierarchical database of eukaryotic protein kinases and protein phosphatases.

PubMed

Wang, Yongbo; Liu, Zexian; Cheng, Han; Gao, Tianshun; Pan, Zhicheng; Yang, Qing; Guo, Anyuan; Xue, Yu

2014-01-01

We present here EKPD (http://ekpd.biocuckoo.org), a hierarchical database of eukaryotic protein kinases (PKs) and protein phosphatases (PPs), the key molecules responsible for the reversible phosphorylation of proteins that are involved in almost all aspects of biological processes. As extensive experimental and computational efforts have been carried out to identify PKs and PPs, an integrative resource with detailed classification and annotation information would be of great value for both experimentalists and computational biologists. In this work, we first collected 1855 PKs and 347 PPs from the scientific literature and various public databases. Based on previously established rationales, we classified all of the known PKs and PPs into a hierarchical structure with three levels, i.e. group, family and individual PK/PP. There are 10 groups with 149 families for the PKs and 10 groups with 33 families for the PPs. We constructed 139 and 27 Hidden Markov Model profiles for PK and PP families, respectively. Then we systematically characterized ∼50,000 PKs and >10,000 PPs in eukaryotes. In addition, >500 PKs and >400 PPs were computationally identified by ortholog search. Finally, the online service of the EKPD database was implemented in PHP + MySQL + JavaScript.

Your place or mine: shared sensory experiences elicit a remapping of peripersonal space.

PubMed

Maister, Lara; Cardini, Flavia; Zamariola, Giorgia; Serino, Andrea; Tsakiris, Manos

2015-04-01

Our perceptual systems integrate multisensory information about objects that are close to our bodies, which allow us to respond quickly and appropriately to potential threats, as well as act upon and manipulate useful tools. Intriguingly, the representation of this area close to our body, known as the multisensory 'peripersonal space' (PPS), can expand or contract during social interactions. However, it is not yet known how different social interactions can alter the representation of PPS. In particular, shared sensory experiences, such as those elicited by bodily illusions such as the enfacement illusion, can induce feelings of ownership over the other's body which has also been shown to increase the remapping of the other's sensory experiences onto our own bodies. The current study investigated whether such shared sensory experiences between two people induced by the enfacement illusion could alter the way PPS was represented, and whether this alteration could be best described as an expansion of one's own PPS towards the other or a remapping of the other's PPS onto one's own. An audio-tactile integration task allowed us to measure the extent of the PPS before and after a shared sensory experience with a confederate. Our results showed a clear increase in audio-tactile integration in the space close to the confederate's body after the shared experience. Importantly, this increase did not extend across the space between participant and confederate, as would be expected if the participant's PPS had expanded. Thus, the pattern of results is more consistent with a partial remapping of the confederate's PPS onto the participant's own PPS. These results have important consequences for our understanding of interpersonal space during different kinds of social interactions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Did the introduction of a prospective payment system for nursing home stays reduce the likelihood of pharmacological management of secondary ischaemic stroke?

PubMed

Lapane, Kate L; Hughes, Carmel M

2006-01-01

Since 1998, a prospective payment system (PPS) for Medicare services provided by nursing homes in the US has been in operation. Concerns have been expressed that the PPS may affect the quality of care delivered to residents. This study evaluates the impact of the PPS on pharmacological secondary ischaemic stroke prevention in nursing homes. The nationally mandated Minimum Data Set and Online Survey Certification and Automated Record data system from 1997 and 2000 for four states were used. We conducted a quasi-experimental study comparing the pharmacological treatment rates for secondary stroke prevention in the pre-PPS period (1997) with those in the post-PPS period (2000) in residents who experienced an ischaemic stroke within 6 months (n1997 = 5008; n2000 = 5243) of living in nursing facilities (n1997 = 1226; n2000 = 1092) in Kansas, Maine, Mississippi or Ohio. The sample was stratified according to recommendations for use of warfarin. Logistic regression models adjusting for clustering effects of residents residing in homes using generalised estimating equations provided estimates of the PPS effect on use of antiplatelets and the use of warfarin. The unadjusted proportion of use of pharmacological agents for the secondary prevention of stroke was similar for warfarin in both time periods and increased for antiplatelets in 2000. Relative to the pre-PPS era, the likelihood of use of antiplatelets increased in the post-PPS era (adjusted odds ratio 1.26; 95% CI 1.15, 1.38); there was no effect on the use of warfarin. Although the lack of a PPS effect on pharmacological management of secondary ischaemic stroke is encouraging, there is still room for improvement in overall stroke management.

The initial impact of Medicare's new prospective payment system for kidney dialysis.

PubMed

Hirth, Richard A; Turenne, Marc N; Wheeler, John R C; Nahra, Tammie A; Sleeman, Kathryn K; Zhang, Wei; Messana, Joseph A

2013-10-01

Medicare implemented a new prospective payment system (PPS) on January 1, 2011. This PPS covers an expanded bundle of services, including services previously paid on a fee-for-service basis. The objectives of the new PPS include more efficient decisions about treatment service combinations and modality choice. Primary data for this study are Medicare claims files for all dialysis patients for whom Medicare is the primary payer. We compare use of key injectable medications under the bundled PPS to use when those drugs were separately billable and examine variability across providers. We also compare each patient's dialysis modality before and after the PPS. Use of relatively expensive drugs, including erythropoiesis-stimulating agents, declined substantially after institution of the new PPS, whereas use of iron products, often therapeutic substitutes for erythropoiesis-stimulating agents, increased. Less expensive vitamin D products were substituted for more expensive types. Drug spending overall decreased by ∼$25 per session, or about 5 times the mandated reduction in the base payment rate of ∼$5. Use of peritoneal dialysis increased in 2011 after being nearly flat in the years prior to the PPS, with the increase concentrated in patients in their first or second year of dialysis. Home hemodialysis continued to increase as a percentage of total dialysis services, but at a rate similar to the pre-PPS trend. The expanded bundle dialysis PPS provided incentives for the use of lower cost therapies. These incentives seem to have motivated dialysis providers to move toward lower cost methods of care in both their use of drugs and choice of modalities. Copyright © 2013 National Kidney Foundation, Inc. All rights reserved.

An extended model for the repression of photosynthesis genes by the AppA/PpsR system in Rhodobacter sphaeroides.

PubMed

Pandey, Rakesh; Flockerzi, Dietrich; Hauser, Marcus J B; Straube, Ronny

2012-09-01

Purple bacteria derive energy from aerobic respiration or photosynthesis depending on the availability of oxygen and light. Under aerobic conditions, photosynthesis genes are specifically repressed by the PpsR protein. In Rhodobacter sphaeroides, the repressive action of PpsR is antagonized by the blue-light and redox-sensitive flavoprotein AppA, which sequesters PpsR under anaerobic conditions into transcriptionally inactive complexes. However, under semi-aerobic conditions, blue-light excitation of AppA causes the AppA-PpsR complexes to dissociate, again leading to a repression of photosynthesis genes. We have recently developed a simple mathematical model suggesting that this phenotype arises from the formation of a maximum in the response curve of reduced PpsR at intermediate oxygen concentrations. However, this model focused mainly on the oxygen-dependent interactions whereas light regulation was only implemented in a simplified manner. In the present study, we incorporate a more detailed mechanism for the light-dependent interaction between AppA and PpsR, which now allows for a direct comparison with experiments. Specifically, we take into account that, upon blue-light excitation, AppA undergoes a conformational change, creating a long-lived signalling state causing the dissociation of the AppA-PpsR complexes. The predictions of the extended model are found to be in good agreement with experimental results on the light-dependent repression of photosynthesis genes under semi-aerobic conditions. We also identify the potential kinetic and stoichiometric constraints that the interplay between light and redox regulation imposes on the functionality of the AppA/PpsR system, especially with respect to a possible bistable response. © 2012 The Authors Journal compilation © 2012 FEBS.

Preparation of Composite Coating on AZ91D Magnesium Alloy by Silica Sol-Micro Oxidation

NASA Astrophysics Data System (ADS)

Shao, Zhongcai; Zhang, Feifei; Zhao, Ruiqiang; Shen, Xiaoyi

2016-03-01

Composite coating was prepared on AZ91D magnesium alloy with a new method which combined silica sol with micro-arc oxidation (MAO). The MAO coating was prepared on the basis of MAO solution, and then coated by sol-gel process. The composite coating was obtained after second MAO treatment. Scanning electron microscopy coupled with X-ray diffraction (XRD), energy spectrum analysis and electrochemical testing was applied to characterize the properties of MAO coating and composite coating. The experimental test results indicated that the Si element derived from SiO2 gel particle embedded into the MAO coating by second MAO treatment. The surface of composite coating became dense and the holes were smaller with silica sol sealing process. The corrosion resistance of composite coating was improved than the MAO coating.

Some Aspects of Psychophysiological Support of Crew Member's Performance Reliability in Space Flight

NASA Astrophysics Data System (ADS)

Nechaev, A. P.; Myasnikov, V. I.; Stepanova, S. I.; Isaev, G. F.; Bronnikov, S. V.

The history of cosmonautics demonstrates many instances in which only crewmembers' intervention allowed critical situations to be resolved, or catastrophes to be prevented. However, during "crew-spacecraft" system operation human is exposed by influence of numerous flight factors, and beforehand it is very difficult to predict their effects on his functional state and work capacity. So, the incidents are known when unfavorable alterations of crewmember's psychophysiological state (PPS) provoked errors in task performance. The objective of the present investigation was to substantiate the methodological approach directed to increase reliability of a crewmember performance (human error prevention) by means of management of his/her PPS. The specific aims of the investigation were: 1) to evaluate the statistical significance of the interrelation between crew errors (CE) and crewmember's PPS, and 2) to develop the way of PPS management. At present, there is no conventional method to assess combined effect of flight conditions (microgravity, confinement, psychosocial factors, etc.) on crewmembers' PPS. For this purpose experts of the Medical Support Group (psychoneurologists and psychologists) at the Moscow Mission Control Center analyze information received during radio and TV contacts with crew. Peculiarities of behavior, motor activity, sleep, speech, mood, emotional reactions, well-being and sensory sphere, trend of dominant interests and volitional acts, signs of deprivation phenomena are considered as separate indicators of crewmember's PPS. The set of qualitative symptoms reflecting PPS alterations and corresponding to them ratings (in arbitrary units) was empirically stated for each indicator. It is important to emphasize that symptoms characterizing more powerful PPS alterations have higher ratings. Quantitative value of PPS integral parameter is calculating by adding up the ratings of all separate indicators over a day, a week, or other temporal interval (in the present investigation - over a week). As a result of processing the data collected during 14 "Mir" station Missions, the significant dependence of CE frequency on value of PPS integral parameter has been established. This dependence demonstrates growth of CE frequency with aggravation of crewmembers' PPS. Additionally, a significant positive correlation between PPS integral parameter and crew work-rest schedule (WRS) intensity has been also found (r=0.71, p<0.05). The WRS intensity was characterized by sleep-wake phase shifts and surplus workload (separate indicators) and quantitative evaluations of both separate and integral indicators were calculated by analogy with psychophysiological parameters. These findings form the basis of the approach to PPS crewmember's management by reduction of the WRS intensity (eliminating separate flight tasks, night work, etc.). Utilization of the approach makes it possible to decrease CE quantity by means of normalization of crewmembers functional state.

The impacts of migraine and anxiety disorders on painful physical symptoms among patients with major depressive disorder.

PubMed

Hung, Ching-I; Liu, Chia-Yih; Chen, Ching-Yen; Yang, Ching-Hui; Wang, Shuu-Jiun

2014-11-10

No study has simultaneously investigated the impacts of migraine and anxiety disorders on painful physical symptoms (PPS) among patients with major depressive disorder (MDD). The study aimed to investigate this issue. This open-label study enrolled 155 outpatients with MDD, who were then treated with venlafaxine 75 mg per day for four weeks. Eighty-five participants with good compliance completed the treatment. Migraine was diagnosed according to the International Classification of Headache Disorders. MDD and anxiety disorders were diagnosed using the Structured Clinical Interview for DSM-IV-TR. The visual analog scale (VAS) was used to evaluate the severity of eight PPS. Multiple linear and logistic regressions were used to investigate the impacts of migraine and anxiety disorders on PPS. Compared with patients without migraine, patients with migraine had a greater severity of PPS at baseline and post-treatment. After controlling for demographic variables and depressive severity, migraine independently predicted the intensities of eight PPS at baseline and four PPS post-treatment. Moreover, migraine independently predicted poorer treatment responses of chest pain and full remission of pains in the head, chest, neck and/or shoulder. Anxiety disorders predicted less full remission of pains in the abdomen and limbs. Migraine and anxiety disorders have negative impacts on PPS among patients with MDD. Integrating the treatment of migraine and anxiety disorders into the management of depression might help to improve PPS and the prognosis of MDD.

Maximizing MST's inductive capability with a Bp programmable power supply

NASA Astrophysics Data System (ADS)

Chapman, B. E.; Holly, D. J.; Jacobson, C. M.; McCollam, K. J.; Morin, J. C.; Sarff, J. S.; Squitieri, A.

2016-10-01

A major goal of the MST program is the advancement of inductive control for the development of both the RFP's fusion potential and, synergistically, the predictive capability of fusion science. This entails programmable power supplies (PPS's) for the Bt and Bp circuits. A Bt PPS is already in place, allowing advanced RFP operation and the production of tokamak plasmas, and a Bp PPS prototype is under construction. To explore some of the new capabilities to be provided by the Bp PPS, the existing Bt PPS has been temporarily connected to the Bp circuit. One key result is new-found access to very low Ip (20 kA) and very low Lundquist number, S (104). At this low S, simulation of RFP plasmas with the MHD code NIMROD is readily achievable, and work toward validation of extended MHD models using NIMROD is underway with direct comparisons to these MST plasmas. The full Bp PPS will also provide higher Ip and S than presently possible, allowing MST to produce plasmas with S spanning as much as five orders of magnitude, a dramatic extension of MST's capability. In these initial tests, the PPS has also increased five-fold MST's Ip flattop duration, to about 100 ms. This, coupled with the recently demonstrated PPS ability to drive large-amplitude sinusoidal oscillations in Ip, will allow tests of extended-duration oscillating field current drive, the goal of which is ac sustainment of a quasi-dc plasma current. Work supported by US DOE.

Mechanical and tribological property of single layer graphene oxide reinforced titanium matrix composite coating

NASA Astrophysics Data System (ADS)

Hu, Zengrong; Li, Yue; Fan, Xueliang; Chen, Feng; Xu, Jiale

2018-04-01

Single layer grapheme oxide Nano sheets and Nano titanium powder were dispersed in deionized water by ultrasonic dispersion. Then the mixed solution was pre-coating on AISI4140 substrate. Using laser sintering process to fabricated grapheme oxide and Ti composite coating. Microstructures and composition of the composite coating was studied by Scanning Electron Microscopy (SEM), x-ray diffract meter (XRD) and Raman spectroscopy. Raman spectrum, XRD pattern and SEM results proved that grapheme oxide sheets were dispersed in the composite coating. The composite coating had much higher average Vickers hardness values than that of pure Ti coating. The tribological performance of the composite coatings became better while the suitable GO content was selected. For the 2.5wt. % GO content coating, the friction coefficient was reduced to near 0.1.

Improved Mechanical Compatibility and Cytocompatibility of Ta/Ti Double-Layered Composite Coating

NASA Astrophysics Data System (ADS)

Ding, Ding; Xie, Youtao; Li, Kai; Huang, Liping; Zheng, Xuebin

2017-08-01

In order to improve the mechanical compatibility and cytocompatibility of titanium implants, a composite coating with double layers composed of tantalum and titanium was designed and prepared using plasma spraying technology. In the composite coating, the upper tantalum layer provides a good biocompatibility, and the sublayer of titanium with a porous structure ensures the low elastic modulus. Results show that the fabricated composite coating exhibits a relatively low elastic modulus of 26.7 GPa, which is close to the elastic modulus of human cortical bone. In vitro cytocompatibility evaluation of the composite coating shows that the human bone marrow stromal cells exhibit enhanced adhesion and spreading performance on the double-layered composite coating in comparison with the single-layered titanium coating. In order to eliminate the misgivings of chemical stability of the composite coating in clinical application, electrochemical corrosion of the coating was examined. The results obtained revealed a very weak galvanic corrosion between the tantalum and titanium in the composite coating, which would ensure the safety of the coating in vivo.

Biodegradation performance of a chitosan coated magnesium-zinc-tricalcium phosphate composite as an implant.

PubMed

Zhao, Jun; Chen, Liangjian; Yu, Kun; Chen, Chang; Dai, Yilong; Qiao, Xueyan; Yan, Yang

2014-09-01

A Mg-Zn-tricalcium phosphate composite with a chitosan coating was prepared in this investigation to study its biodegradation performance both in vitro and in vivo conditions. The in vitro test results show that the immersion corrosion rate, the pH values of the simulated body fluids and the released metal ion concentration of the chitosan coated composite are all lower than those of the uncoated composite. The in vitro cytotoxicity test shows that the chitosan coated specimens is safe for cellular applications. When the chitosan coated composite is tested in vivo, the concentration of metal ions from the composite observed in the venous blood of Zelanian rabbits is less than the uncoated composite specimens. The chitosan coating slows down the in vivo degradation of the composite after surgery. In vivo testing also indicates that the chitosan coated composite is harmless to important visceral organs, including the heart, kidneys, and liver of the rabbits. The new bone formation surrounding the chitosan coated composite implant shows that the composite improves the concrescence of the bone tissues. The chitosan coating is an effective corrosion resistant layer that reduces the hydrogen release of the implant composite, thereby decreasing the subcutaneous gas bubbles formed.

METAS New Time Scale Generation System - A Progress Report

DTIC Science & Technology

2007-01-01

and a TWSTFT station are used for remote T&F comparisons. The GPS TAI link is driven by one of the atomic clocks defined as the REF clock...UTC(CH.P) paper clock TA(CH.P) paper clock TWSTFT link GPS link CH00 WAB1 H-maser 1-PPS H-maser 1-PPS REF 1-PPS 5-MHz from all clocks UTC(CH.R) 1-PPS...lost, the only consequence would be a transient of UTC (CH.P), which can be corrected by a subsequent steering. The GPS and TWSTFT links can be

Incidental and Underreported Pleural Plaques at Chest CT: Do Not Miss Them—Asbestos Exposure Still Exists

PubMed Central

Contorni, Francesco; Gentili, Francesco; Pinto, Antonio; Sisinni, Antonietta Gerardina; Paolucci, Valentina; Romeo, Riccardo; Sartorelli, Pietro

2017-01-01

Pleural plaques (PPs) may be a risk factor for mortality from lung cancer in asbestos-exposed workers and are considered to be a marker of exposure. Diagnosing PPs is also important because asbestos-exposed patients should be offered a health surveillance that is mandatory in many countries. On the other hand PPs are useful for compensation purposes. In this study we aimed to evaluate the prevalence, as incidental findings, and the underreporting rate of PPs in chest CT scans (CTs) performed in a cohort of patients (1512) who underwent chest CT with a slice thickness no more than 1.25 mm. PPs were found in 76 out of 1482 patients (5.1%); in 13 out of 76 (17,1%) CTs were performed because of clinical suspicion of asbestos exposure and 5 of them (38%) were underreported by radiologist. In the remaining 63 cases (82.9%) there was no clinical suspicion of asbestos exposure at the time of CTs (incidental findings) and in 38 of these 63 patients (60.3%) PPs were underreported. Reaching a correct diagnosis of PPs requires a good knowledge of normal locoregional anatomy and rigorous technical approach in chest CT execution. However the job history of the patient should always be kept in mind. PMID:28656146

Long-term stability of the Leksell Gamma Knife{sup ®} Perfexion™ patient positioning system (PPS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Novotny, J., E-mail: josef.novotnyml@homolka.cz; Department of Medical Physics, Na Homolce Hospital, Prague 150 30; Institute of Biophysics and Informatics, First Faculty of Medicine, Charles University in Prague, Prague 120 00

2014-03-15

Purpose: To assess the long-term mechanical stability and accuracy of the patient positioning system (PPS) of the Leksell Gamma Knife{sup ®} Perfexion™ (LGK PFX). Methods: The mechanical stability of the PPS of the LGK PFX was evaluated using measurements obtained between September 2007 and June 2011. Three methods were employed to measure the deviation of the coincidence of the radiological focus point (RFP) and the PPS calibration center point (CCP). In the first method, the onsite diode test tool with single diode detector was used together with the 4 mm collimator on a daily basis. In the second method, amore » service diode test tool with three diode detectors was used biannually at the time of the routine preventive maintenance. The test performed with the service diode test tool measured the deviations for all three collimators 4, 8, and 16 mm and also for three different positions of the PPS. The third method employed the conventional film pin-prick method. This test was performed annually for the 4 mm collimator at the time of the routine annual QA. To estimate the effect of the patient weight on the performance of the PPS, the focus precision tests were also conducted with varying weights on the PPS using a set of lead bricks. Results: The average deviations measured from the 641 daily focus precision tests were 0.1 ± 0.1, 0.0 ± 0.0, and 0.0 ± 0.0 mm, respectively, for the 4 mm collimator in the X (left/right of the patient), Y (anterior/posterior of the patient), and Z (superior/inferior of the patient) directions. The average of the total radial deviations as measured during ten semiannual measurements with the service diode test tool were 0.070 ± 0.029, 0.060 ± 0.022, and 0.103 ± 0.028 mm, respectively for the central, long, and short diodes for the 4 mm collimator. Similarly, the average total radial deviations measured during the semiannual measurements for the 4, 8, and 16 mm collimators and using the central diode were 0.070 ± 0.029, 0.097 ± 0.025, 0.159 ± 0.028 mm, respectively. The average values of the deviations as obtained from the five annual film pin-prick tests for the 4 mm collimator were 0.10 ± 0.06, 0.06 ± 0.09, and 0.03 ± 0.03 mm for the X, Y, Z stereotactic directions, respectively. Only a minor change was observed in the total radial deviations of the PPS as a function of the simulated patient weight up to 202 kg on the PPS. Conclusions: Excellent long-term mechanical stability and high accuracy was observed for the PPS of the LGK PFX. No PPS recalibration or any adjustment in the PPS was needed during the monitored period of time. Similarly, the weight on the PPS did not cause any significant disturbance in the performance of the PPS for up to 202 kg simulated patient weight.« less

Rheological and tribological properties of carbon nanotube/thermoplastic nanocomposites incorporating inorganic fullerene-like WS2 nanoparticles.

PubMed

Díez-Pascual, Ana M; Naffakh, Mohammed; Marco, Carlos; Ellis, Gary

2012-07-12

The rheological and tribological properties of single-walled carbon nanotube (SWCNT)-reinforced poly(phenylene sulphide) (PPS) and poly(ether ether ketone) (PEEK) nanocomposites prepared via melt-extrusion were investigated. The effectiveness of employing a dual-nanofiller strategy combining polyetherimide (PEI)-wrapped SWCNTs with inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles for property enhancement of the resulting hybrid composites was evaluated. Viscoelastic measurements revealed that the complex viscosity η, storage modulus G', and loss modulus G″ increased with SWCNT content. In the low-frequency region, G' and G″ became almost independent of frequency at higher SWCNT loadings, suggesting a transition from liquid-like to solid-like behavior. The incorporation of increasing IF-WS2 contents led to a progressive drop in η and G' due to a lubricant effect. PEEK nanocomposites showed lower percolation threshold than those based on PPS, ascribed to an improved SWCNT dispersion due to the higher affinity between PEI and PEEK. The SWCNTs significantly lowered the wear rate but only slightly reduced the coefficient of friction. Composites with both nanofillers exhibited improved wear behavior, attributed to the outstanding tribological properties of these nanoparticles and a synergistic reinforcement effect. The combination of SWCNTs with IF-WS2 is a promising route for improving the tribological and rheological performance of thermoplastic nanocomposites.

Characterization of Microstructure and Wear Resistance of PEO Coatings Containing Various Microparticles on Ti6Al4V Alloy

NASA Astrophysics Data System (ADS)

Li, Xinyi; Dong, Chaofang; Zhao, Qing; Pang, Yu; Cheng, Fasong; Wang, Shuaixing

2018-02-01

Titania-based composite coatings were prepared by plasma electrolytic oxidation (PEO) treatment of Ti6Al4V alloy in electrolyte with α-Al2O3, Cr2O3 or h-BN microparticles in suspension. The microstructure, composition of PEO composite coatings were analyzed by SEM, EDS and XRD. The wear resistance of composite ceramic coatings was studied by ball-on-disk wear test at ambient temperature and 300 °C. The results showed that the addition of microparticles accelerated the growth rate of PEO coating and changed the microstructure and composition of PEO coating. PEO coating was porous and mainly composed of rutile-TiO2, anatase-TiO2 and Al2TiO5. PEO/α-Al2O3 (Cr2O3 or h-BN) composite coating only had small micropores and appeared some α-Al2O3 (Cr2O3 or h-BN) phase. Besides, the addition of α-Al2O3 (Cr2O3 or h-BN) microparticles greatly improved the wear resistance of PEO coating. At ambient temperature, abrasive wear dominated the wear behavior of PEO coating, but abrasive wear and adhesive peel simultaneously happened at 300 °C. Whether at ambient temperature or 300 °C, PEO composite coating had better wear resistance than PEO coating. Besides, PEO/h-BN composite coating outperformed other composite coatings regardless of the temperature.

Pleural plaques and their effect on lung function in Libby vermiculite miners.

PubMed

Clark, Kathleen A; Flynn, J Jay; Goodman, Julie E; Zu, Ke; Karmaus, Wilfried J J; Mohr, Lawrence C

2014-09-01

Multiple studies have investigated the relationship between asbestos-related pleural plaques (PPs) and lung function, with disparate and inconsistent results. Most use chest radiographs to identify PPs and simple spirometry to measure lung function. High-resolution CT (HRCT) scanning improves the accuracy of PP identification. Complete pulmonary function tests (PFTs), including spirometry, lung volumes, and diffusing capacity of the lung for carbon monoxide, provide a more definitive assessment of lung function. The goal of this study was to determine, using HRCT scanning and complete PFTs, the effect of PPs on lung function in Libby vermiculite miners. The results of HRCT scanning and complete PFTs performed between January 2000 and August 2012 were obtained from the medical records of 166 Libby vermiculite miners. Multivariate regression analyses with Tukey multivariate adjustment were used to assess statistical associations between the presence of PPs and lung function. Adjustments were made for age, BMI, smoking history, duration of employment, and years since last occupational asbestos exposure. Nearly 90% of miners (n = 149) had evidence of PPs on HRCT scan. No significant differences in spirometry results, lung volumes, or diffusing capacity of the lung for carbon monoxide were found between miners with PPs alone and miners with normal HRCT scans. Miners with both interstitial fibrosis and the presence of PPs had a significantly decreased total lung capacity in comparison with miners with normal HRCT scans (P = .02). Age, cumulative smoking history, and BMI were significant covariates that contributed to abnormal lung function. Asbestos-related PPs alone have no significant effect on lung function in Libby vermiculite miners.

Psychophysiological Approach To Support Of Cosmonauts Performance Reliability

NASA Astrophysics Data System (ADS)

Nechaev, A. P.

Space flight factors may effect negatively on psychophysiological state (PPS) and work capacity of crewmembers, lead to errors in tasks performance. Such errors cannot be entirely prevented during "crew-spacecraft" system designing and/or crewmembers training as they are consequence of a human "psychophysiological troubles". In the present investigation we paid special attention to work and rest schedule (WRS) intensity due to sleep-wake rhythm disturbances and crewmembers overload may cause PPS aggravation. By methods of the correlation analysis of the data collected during 9 "Mir" missions (18 Russian cosmonauts, 226 flight weeks) the significant (p<0.05) interrelations between WRS intensity and cosmonauts PPS as well as between cosmonauts PPS and crewmembers errors (CE) frequency have been established. It allows to consider WRS intensity as "the controlling factor" in relation to crewmember's PPS. Quantitative characteristics of these interrelations have been also determined. This findings have been used for development of algorithm of crewmember's PPS management with the purpose of decrease in CE frequency. The algorithm can be briefly described in the following kind. On the basis of the analysis of crew forthcoming work experts should assess WRS intensity, possible crewmembers PPS alterations, and expected CE frequency. If CE frequency is allowable the management may be limited to recommendations that operative vigilance increase. If CE frequency is higher allowable it is necessary to carry out the measures on crewmembers PPS normalization by means of decrease in WRS intensity. The algorithm is intended for use in the on-ground expert system of psychophysiological support of cosmonauts performance.

78 FR 3031 - Amended Certification Regarding Eligibility To Apply for Worker Adjustment Assistance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-15

... PRINTING SYSTEMS (PPS), SUPPLY CHAIN OPERATIONS (FORMERLY KNOWN AS IWS), VANCOUVER, WA. In accordance with... Services (IWS) and Supply Chain Operations (formerly known as IWS) units. The workers within PPS (both... Group, Vancouver, Washington (TA-W-81,739A), and H-P, PPS, Supply Chain Operations, Vancouver...

Road accidents and business cycles in Spain.

PubMed

Rodríguez-López, Jesús; Marrero, Gustavo A; González, Rosa Marina; Leal-Linares, Teresa

2016-11-01

This paper explores the causes behind the downturn in road accidents in Spain across the last decade. Possible causes are grouped into three categories: Institutional factors (a Penalty Point System, PPS, dating from 2006), technological factors (active safety and passive safety of vehicles), and macroeconomic factors (the Great recession starting in 2008, and an increase in fuel prices during the spring of 2008). The PPS has been blessed by incumbent authorities as responsible for the decline of road fatalities in Spain. Using cointegration techniques, the GDP growth rate, the fuel price, the PPS, and technological items embedded in motor vehicles appear to be statistically significantly related with accidents. Importantly, PPS is found to be significant in reducing fatal accidents. However, PPS is not significant for non-fatal accidents. In view of these results, we conclude that road accidents in Spain are very sensitive to the business cycle, and that the PPS influenced the severity (fatality) rather than the quantity of accidents in Spain. Importantly, technological items help explain a sizable fraction in accidents downturn, their effects dating back from the end of the nineties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Visualization of GPM Standard Products at the Precipitation Processing System (PPS)

NASA Astrophysics Data System (ADS)

Kelley, O.

2010-12-01

Many of the standard data products for the Global Precipitation Measurement (GPM) constellation of satellites will be generated at and distributed by the Precipitation Processing System (PPS) at NASA Goddard. PPS will provide several means to visualize these data products. These visualization tools will be used internally by PPS analysts to investigate potential anomalies in the data files, and these tools will also be made available to researchers. Currently, a free data viewer called THOR, the Tool for High-resolution Observation Review, can be downloaded and installed on Linux, Windows, and Mac OS X systems. THOR can display swath and grid products, and to a limited degree, the low-level data packets that the satellite itself transmits to the ground system. Observations collected since the 1997 launch of the Tropical Rainfall Measuring Mission (TRMM) satellite can be downloaded from the PPS FTP archive, and in the future, many of the GPM standard products will also be available from this FTP site. To provide easy access to this 80 terabyte and growing archive, PPS currently operates an on-line ordering tool called STORM that provides geographic and time searches, browse-image display, and the ability to order user-specified subsets of standard data files. Prior to the anticipated 2013 launch of the GPM core satellite, PPS will expand its visualization tools by integrating an on-line version of THOR within STORM to provide on-the-fly image creation of any portion of an archived data file at a user-specified degree of magnification. PPS will also provide OpenDAP access to the data archive and OGC WMS image creation of both swath and gridded data products. During the GPM era, PPS will continue to provide realtime globally-gridded 3-hour rainfall estimates to the public in a compact binary format (3B42RT) and in a GIS format (2-byte TIFF images + ESRI WorldFiles).

Comparing the outcomes of two strategies for colorectal tumor detection: policy-promoted screening program versus health promotion service.

PubMed

Wu, Ping-Hsiu; Lin, Yu-Min; Liao, Chao-Sheng; Chang, Hung-Chuen; Chen, Yu-Hung; Yang, Kuo-Ching; Shih, Chia-Hui

2013-06-01

The Taiwanese government has proposed a population-based colorectal tumor detection program for the average-risk population. This study's objectives were to understand the outcomes of these screening policies and to evaluate the effectiveness of the program. We compared two databases compiled in one medical center. The "policy-promoted cancer screening" (PPS) database was built on the basis of the policy of the Taiwan Bureau of National Health Insurance for cancer screening. The "health promotion service" (HPS) database was built to provide health check-ups for self-paid volunteers. Both the PPS and HPS databases employ the immunochemical fecal occult blood test (iFOBT) and colonoscopy for colorectal tumor screening using different strategies. A comparison of outcomes between the PPS and HPS included: (1) quality indicators-compliance rate, cecum reaching rate, and tumor detection rate; and (2) validity indicators-sensitivity, specificity, positive, and negative predictive values for detecting colorectal neoplasms. A total of 10,563 and 1481 individuals were enrolled in PPS and HPS, respectively. Among quality indicators, there was no statistically significant difference in the cecum reaching rate between PPS and HPS. The compliance rates were 56.1% for PPS and 91.8% for HPS (p < 0.001). The advanced adenoma detection rates of PPS and HPS were 1.0% and 3.6%, respectively (p < 0.01). The carcinoma detection rates were 0.3% and 0.4%, respectively (p = 0.59). For validity indicators, PPS provides only a positive predictive value for colorectal tumor detection. HPS provides additional validity indicators, including sensitivity, specificity, positive predictive value, and negative predictive value, for colorectal tumor screening. In comparison with the outcomes of the HPS database, the screening efficacy of the PPS database is even for detecting colorectal carcinoma but is limited in detecting advanced adenoma. HPS may provide comprehensive validity indicators and will be helpful in adjusting current policies for improving screening performance. Copyright © 2013. Published by Elsevier B.V.

Involving private practitioners in the Indian tuberculosis programme: a randomised trial.

PubMed

Yellappa, Vijayashree; Battaglioli, Tullia; Gurum, Sanath Kumar; Narayanan, Devadasan; Van der Stuyft, Patrick

2018-05-01

To assess a multicomponent intervention to improve private practitioners (PPs) involvement in referral of presumptive pulmonary TB (PTB) cases to the Revised National TB Control Programme (RNTCP) for sputum examination. Randomised controlled trial. We randomly allocated all 189 eligible PPs in Tumkur city, South India, to intervention or control arm. The intervention, implemented between December 2014 and January 2016, included two sets of activities, one targeted at health system strengthening (building RNTCP staff capacity to collaborate with PPs, provision of feedback on referrals through SMS) and one targeted at intervention PPs (training in RNTCP, provision of referral pads and education materials and monthly visits to PPs by RNTCP staff). Crude and adjusted referral and PTB case-finding rate ratios were calculated with negative binomial regression. PPs referred 836 individuals (548 from intervention and 169 from control arm PPs) of whom 176 were diagnosed with bacteriologically confirmed PTB. The proportion (95% confidence interval) of referring PPs [0.59 (0.49, 0.68) vs. 0.42 (0.32, 0.52) in the intervention and control arm, respectively], mean referral rate per PP-year [(5.7 (3.8, 8.7) vs. 1.8 (1.2, 2.8)] and smear-positive PTB case-finding rate per PP-year [(1.5 (0.9, 2.2) vs. 0.6 (0.3, 0.9)] were significantly higher in the intervention than the control arm. Stratifying by qualification, a statistically significant difference in the above indicators remained only among GPs and internists. Overall, surgeons, paediatricians and gynaecologists referred few patients. PP referrals contributed to 20% of the sputum smear positive PTB cases detected by RNTCP in Tumkur city (14% were from intervention arm PPs). We demonstrated the effectiveness of a health system-oriented intervention to improve PP's referrals of presumptive PTB cases to RNTCP. © 2018 John Wiley & Sons Ltd.

A modified method for locating parapharyngeal space neoplasms on magnetic resonance images: implications for differential diagnosis

PubMed Central

Liu, Xue-Wen; Wang, Ling; Li, Hui; Zhang, Rong; Geng, Zhi-Jun; Wang, De-Ling; Xie, Chuan-Miao

2014-01-01

The parapharyngeal space (PPS) is an inverted pyramid-shaped deep space in the head and neck region, and a variety of tumors, such as salivary gland tumors, neurogenic tumors, nasopharyngeal carcinomas with parapharyngeal invasion, and lymphomas, can be found in this space. The differential diagnosis of PPS tumors remains challenging for radiologists. This study aimed to develop and test a modified method for locating PPS tumors on magnetic resonance (MR) images to improve preoperative differential diagnosis. The new protocol divided the PPS into three compartments: a prestyloid compartment, the carotid sheath, and the areas outside the carotid sheath. PPS tumors were located in these compartments according to the displacements of the tensor veli palatini muscle and the styloid process, with or without blood vessel separations and medial pterygoid invasion. This protocol, as well as a more conventional protocol that is based on displacements of the internal carotid artery (ICA), was used to assess MR images captured from a series of 58 PPS tumors. The consequent distributions of PPS tumor locations determined by both methods were compared. Of all 58 tumors, our new method determined that 57 could be assigned to precise PPS compartments. Nearly all (13/14; 93%) tumors that were located in the pre-styloid compartment were salivary gland tumors. All 15 tumors within the carotid sheath were neurogenic tumors. The vast majority (18/20; 90%) of trans-spatial lesions were malignancies. However, according to the ICA-based method, 28 tumors were located in the pre-styloid compartment, and 24 were located in the post-styloid compartment, leaving 6 tumors that were difficult to locate. Lesions located in both the pre-styloid and the post-styloid compartments comprised various types of tumors. Compared with the conventional ICA-based method, our new method can help radiologists to narrow the differential diagnosis of PPS tumors to specific compartments. PMID:25104280

Thyroid hormone concentrations, disease, physical function, and mortality in elderly men.

PubMed

van den Beld, Annewieke W; Visser, Theo J; Feelders, Richard A; Grobbee, Diederick E; Lamberts, Steven W J

2005-12-01

Physiological changes in thyroid hormone concentrations might be related to changes in the overall physical function in the elderly. We determined to what extent thyroid hormone concentrations are related to physical function and mortality in elderly men. A longitudinal population study (the Zoetermeer study) was conducted. Mortality was registered in the subsequent 4 yr. Four hundred three independently and ambulatory living men (aged 73-94 yr) participated. The study examined the association between serum thyroid hormones and parameters of physical function as well as the association with mortality. TSH, free T4 (FT4) total T4, T3, rT3, and T4-binding globulin were measured. Physical function was estimated by the number of problems in activities of daily living, a measure of physical performance score (PPS), leg extensor strength and grip strength, bone density, and body composition. Serum rT3 increased significantly with age and the presence of disease. Sixty-three men met the biochemical criteria for the low T3 syndrome (decreased serum T3 and increased serum rT3). This was associated with a lower PPS, independent of disease. Furthermore, higher serum FT4 (within the normal range of healthy adults) and rT3 (above the normal range of healthy adults) were related with a lower grip strength and PPS, independent of age and disease. Isolated low T3 was associated with a better PPS and a higher lean body mass. Low FT4 was related to a decreased risk of 4-yr mortality. In a population of independently living elderly men, higher FT4 and rT3 concentrations are associated with a lower physical function. High serum rT3 may result from a decreased peripheral metabolism of thyroid hormones due to the aging process itself and/or disease and may reflect a catabolic state. Low serum FT4 is associated with a better 4-yr survival; this may reflect an adaptive mechanism to prevent excessive catabolism.

Development of Regulatory Documents for Creation (Upgrade) of Physical Protection Systems under the Russian/American MPC&A Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izmaylov, Alexandr V.; Babkin, Vladimir; Kurov, Valeriy

2009-10-07

The development of new or the upgrade of existing physical protection systems (PPS) for nuclear facilities involves a multi-step and multidimensional process. The process consists of conceptual design, design, and commissioning stages. The activities associated with each of these stages are governed by Russian government and agency regulations. To ensure a uniform approach to development or upgrading of PPS at Russian nuclear facilities, the development of a range of regulatory and methodological documents is necessary. Some issues of PPS development are covered by the regulatory documents developed by Rosatom, as well as other Russian agencies with nuclear facilities under theirmore » control. This regulatory development has been accomplished as part of the U.S.-Russian MPC&A cooperation or independently by the Russian Federation. While regulatory coverage is extensive, there are a number of issues such as vulnerability analysis, effectiveness assessment, upgrading PPS, and protection of information systems for PPS that require additional regulations be developed. This paper reports on the status of regulatory coverage for PPS development or upgrade, and outlines a new approach to regulatory document development. It describes the evolutionary process of regulatory development through experience gained in the design, development and implementation of PPS as well as experience gained through the cooperative efforts of Russian and U.S. experts involved the development of MPC&A regulations.« less

Friction and wear of plasma-sprayed coatings containing cobalt alloys from 25 deg to 650 deg in air

NASA Technical Reports Server (NTRS)

Sliney, H. E.; Jacobson, T. P.

1979-01-01

Four different compositions of self-lubricating, plasma-sprayed, composite coatings with calcium fluoride dispersed throughout cobalt alloy-silver matrices were evaluated on a friction and wear apparatus. In addition, coatings of the cobalt alloys alone and one coating with a nickel alloy-silver matrix were evaluated for comparison. The wear specimens consisted of two, diametrically opposed, flat rub shoes sliding on the coated, cylindrical surface of a rotating disk. Two of the cobalt composite coatings gave a friction coefficient of about 0.25 and low wear at room temperature, 400 and 650 C. Wear rates were lower than those of the cobalt alloys alone or the nickel alloy composite coating. However, oxidation limited the maximum useful temperature of the cobalt composite coating to about 650 C compared to about 900 C for the nickel composite coating.

Preparation and tribological behavior of Ni-graphene composite coating under room temperature

NASA Astrophysics Data System (ADS)

Chen, Juanjuan; Li, Jianliang; Xiong, Dangsheng; He, Yong; Ji, Yujuan; Qin, Yongkun

2016-01-01

In this paper, Ni-graphene composite coatings with different graphene addition amounts were prepared on 45 steel disk by using dipulse composite electrodeposition technology. Meanwhile, the influence of plating time, bath temperature and load on friction and wear of the coating was studied. The tribological behavior of composite coating was tested against a Si3N4 ceramic ball under dry condition. Cross-sectional morphologies showed that Ni-graphene coating was successfully coated on the substrate with an average thickness of 85 ± 5 μm. XRD analysis concluded that with the increase of addition amount of graphene, the average crystallite size of coating decreased. EDS analyses and Raman spectra proved the presence of graphene. Friction coefficient of composite coating decreased with the increase of graphene addition amounts, while the hardness increased. Meanwhile, the wear resistance of composite coating improved. The optimum experimental conditions were obtained.

A review of recent developments in joining high-performance thermoplastic composites

NASA Astrophysics Data System (ADS)

Cole, K. C.

1991-06-01

There is currently a great deal of interest in the use of thermoplastic polymers as matrices in fiber reinforced composites for high performance applications, such as those encountered in the aerospace industry. These materials include polyether ether ketone (PEEK), polyphenylene sulphide (PPS), polyetherimide (PEI), polyamideimide (PAI), polyamides, polyimides, and polysulphones. A literature review is provided on the different ways of joining high performance thermoplastic composites by adhesive and fusion bonding. The discussion on adhesive bonding includes examination of the performance of specific adhesive/thermoplastic combinations and of techniques for the preparation of composite surfaces: abrasion, etching, flame, and plasma treatments. Thermoplastic composite welding techniques discussed in depth include the following: heated press welding, resistance welding, induction welding, and ultrasonic welding. Works which examine or compare applications for these bonding techniques are also reviewed.

Ripple Effects of PPS on Nursing Homes: Swimming or Drowning in the Funding Stream?

ERIC Educational Resources Information Center

Swan, James H.; And Others

1990-01-01

Of 189 nursing homes, 83 percent reported that Medicare's hospital Prospective Payment System (PPS) affected patient needs, 53 percent said it affected patients and services provided, and 25 percent said it affected referrals to hospitals. PPS effects depended on facility factors of size, Medicare certification, tax status, and on local market…

Incorporation of Fe3O4/CNTs nanocomposite in an epoxy coating for corrosion protection of carbon steel

NASA Astrophysics Data System (ADS)

Pham, Gia Vu; Truc Trinh, Anh; To, Thi Xuan Hang; Duong Nguyen, Thuy; Trang Nguyen, Thu; Hoan Nguyen, Xuan

2014-09-01

In this study Fe3O4/CNTs composite with magnetic property was prepared by attaching magnetic nanoparticles (Fe3O4) to carbon nanotubes (CNTs) by hydrothermal method. The obtained Fe3O4/CNTs composite was characterized by Fourier transform infrared (FTIR) spectroscopy, powder x-ray diffraction and transmission electron microscopy. The Fe3O4/CNTs composite was then incorporated into an epoxy coating at concentration of 3 wt%. Corrosion protection of epoxy coating containing Fe3O4/CNTs composite was evaluated by electrochemical impedance spectroscopy and adhesion measurement. The impedance measurements show that Fe3O4/CNTs composite enhanced the corrosion protection of epoxy coating. The corrosion resistance of the carbon steel coated by epoxy coating containing Fe3O4/CNTs composite was significantly higher than that of carbon steel coated by clear epoxy coating and epoxy coating containing CNTs. FE-SEM photographs of fracture surface of coatings showed good dispersion of Fe3O4/CNTs composite in the epoxy matrix.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kunc, Vlastimil; Lindahl, John M; Dinwiddie, Ralph Barton

The autoclave is a crucial piece of equipment for fabricating Tier 1 polymer composite aerospace structural components with very low void content (i.e. < 5 %). The essential component in this composite manufacturing process is the rigid mold that defines the final shape of the fabricated composite component. The Big Area Additive Manufacturing (BAAM) system located at Oak Ridge National Laboratory s (ORNL) Manufacturing Demonstration Facility (MDF) has been used to manufacture a new generation of in-autoclave tools that can be used to fabricate various aerospace composite parts. Different tools made form Polyphenylene sulfide (PPS) with 50 % by weightmore » carbon fiber and Polyphenylsulfone (PPSU) with 25 % carbon fiber are investigated in this study. The behavior of the printed tools under different temperature ramp rates for the autoclave cycles was observed and analyzed.« less

[Musculoskeletal symptoms in patients with post-polio syndrome].

PubMed

Balzien, B; Hofner, B; Harlander-Weikert, E; Frommelt, P; Bork, H; Forst, R; Fujak, A

2014-06-01

The prevalence of the post-polio syndrome (PPS) is in estimated 50 % of persons with established poliomyelitis with a subsequently stable phase of at least 15 years. The basic mechanism is a loss of motoneuron cells in the spinal cord resulting in muscle weakness and fatigue. In addition pain, cold intolerance and a loss of stamina are frequently reported. There are few studies focusing on the orthopaedic symptoms in the PPS. This study should support the health-care professionals to the address the needs of PPS patients. A questionnaire was developed to collect data on patients who have been diagnosed by a neurologist as fulfilling the criteria of a PPS. It consists of two parts. In the first part, general patient data are collected. In the second part, details of health, pain, and activities of daily living are collected at two points in time: the time of the stable phase immediately after the acute phase of the disease and the phase after the PPS diagnosis. The questionnaires were sent to patients with a diagnosis of PPS. A total of 124 questionnaires were analysed (male: 45, female: 79). Parts of the data were used to calculate a score. It was hypothesised that the score would demonstrate a higher load of orthopaedic symptoms in the PPS phase. The results show that the phase after poliomyelitis (stable phase vs. PPS phase) was associated with significantly different sum score relating to the orthopaedic impairments. The score in the stable phase is on average 18.6 units lower than that in the post-PPS diagnosis phase (p < 0.001). The hypothesis that in the PPS phase the load of orthopaedic symptoms is increased is confirmed by our data. The "loss of functioning in the upper extremity" is also significantly associated with the score (p = 0.004). At the time the survey was taken, patients reveal a high level of musculoskeletal impairments and disabilities after PPS than during the stable phase with regard to general health as well as pain status and performance of daily activities. Age has no significant impact. Many of the patients are severely limited, especially with regard to activities such as walking, climbing stairs, and performing simple household tasks. Since there is no causal therapy for the underlying degeneration of the anterior horn cell pools, treatment is focused on the compensation of the functional limitations. Georg Thieme Verlag KG Stuttgart · New York.

Effect of the cross-linking agent on performances of NaCS-CS/WSC microcapsules.

PubMed

Wu, Qing-Xi; Xu, Xin; Wang, Zu-Li; Yao, Shan-Jing; Tong, Wang-Yu; Chen, Yan

2016-11-01

Based on the properties of oppositely charged natural polysaccharides, the polyelectrolyte complexes (PECs) prepared with chitosan-related polycationic polyelectrolytes and cellulose-related polyanionic polyelectrolytes have been widely concerned for their potential applications as micro-drug-carriers for colon. However, the poor mechanical property of the PECs becomes the obstacle encountered in practical applications. This study investigated the effect of the cross-linking agent (sodium polyphosphate, PPS) on the performances of sodium cellulose sulfate -chitosan/water soluble chitosan (NaCS-CS/WSC) microcapsules. The results revealed that PPS could penetrate through the PEC film and form tighter interior structures compared with the microcapsules without the addition of cross-linking agent. The NaCS-CS microcapsules and NaCS-WSC microcapsules with or without PPS had distinct microstructures, which could be ascribed to the different physicochemical properties of CS and WSC. During the formation process, CS can be dissolved in water under acidic conditions, while WSC can be directly dissolved and protonated in acid-free aqueous providing NH3(+) groups quickly, which resulted in the microstructure's difference. Further analysis showed the NaCS-CS-PPS microcapsules and NaCS-WSC-PPS microcapsules had lower swelling ratios due to their tighter interior microstructures that formed. The cross-linking agent had important effect on the total mass of PECs that produced; moreover, the decline of zeta potential of NaCS-CS-PPS microcapsules was lower than that of NaCS-CS microcapsules, similar trend was found in the NaCS-WSC-PPS microcapsules compared with NaCS-WSC microcapsules, indicating the PPS participated in the interactions and played a role in the microcapsules' formation process. Copyright © 2016 Elsevier B.V. All rights reserved.

The impact of DRGs on the cost and quality of health care in the United States.

PubMed

Davis, C; Rhodes, D J

1988-01-01

The prospective Payment System (PPS) represents a fundamental change in the way the United States government reimburses hospitals for medical services covered under Medicare, a federal health care insurance program for the elderly and disabled. PPS replaced the retrospective cost-based system of payment for Medicare services with a prospective payment system. Under PPS, a predetermined specific rate for each discharge dictates payment according to the diagnosis related group (DRG) in which the discharge is classified. The PPS was intended to create financial incentives that encourage hospitals to restrain the use of resources while providing high-quality inpatient care. Both objectives appear to have been met under PPS. Hospital utilization has declined, average length of stay has fallen, and the locus of care has shifted from the inpatient setting to less costly outpatient settings. The growth in inpatient hospital benefits has slowed and the impending insolvency of the Medicare trust fund has been forestalled. Studies have found no deterioration in the quality of care rendered to Medicare beneficiaries. Neither the mortality rate nor the rate of re-admission (presumably related to premature discharge) increased under PPS. Indeed, PPS appears to have enhanced the quality of inpatient care by discouraging unnecessary and potentially harmful procedures, and by encouraging the concentration of complex procedures in facilities in which the high frequency of these procedures promotes efficiency. Incentive-based reimbursement also appears to have contributed to the growth in alternative delivery systems, such as HMOs and PPOs, which contain costs by maintaining a high volume of a limited range of services. The success of the PPS/DRG system in controlling costs and promoting quality in this country suggests its application in other countries, either as a method of reimbursement or as a product line management tool.

Hierarchical regulation of photosynthesis gene expression by the oxygen-responsive PrrBA and AppA-PpsR systems of Rhodobacter sphaeroides.

PubMed

Gomelsky, Larissa; Moskvin, Oleg V; Stenzel, Rachel A; Jones, Denise F; Donohue, Timothy J; Gomelsky, Mark

2008-12-01

In the facultatively phototrophic proteobacterium Rhodobacter sphaeroides, formation of the photosynthetic apparatus is oxygen dependent. When oxygen tension decreases, the response regulator PrrA of the global two-component PrrBA system is believed to directly activate transcription of the puf, puh, and puc operons, encoding structural proteins of the photosynthetic complexes, and to indirectly upregulate the photopigment biosynthesis genes bch and crt. Decreased oxygen also results in inactivation of the photosynthesis-specific repressor PpsR, bringing about derepression of the puc, bch, and crt operons. We uncovered a hierarchical relationship between these two regulatory systems, earlier thought to function independently. We also more accurately assessed the spectrum of gene targets of the PrrBA system. First, expression of the appA gene, encoding the PpsR antirepressor, is PrrA dependent, which establishes one level of hierarchical dominance of the PrrBA system over AppA-PpsR. Second, restoration of the appA transcript to the wild-type level is insufficient for rescuing phototrophic growth impairment of the prrA mutant, whereas inactivation of ppsR is sufficient. This suggests that in addition to controlling appA transcription, PrrA affects the activity of the AppA-PpsR system via an as yet unidentified mechanism(s). Third, PrrA directly activates several bch and crt genes, traditionally considered to be the PpsR targets. Therefore, in R. sphaeroides, the global PrrBA system regulates photosynthesis gene expression (i) by rigorous control over the photosynthesis-specific AppA-PpsR regulatory system and (ii) by extensive direct transcription activation of genes encoding structural proteins of photosynthetic complexes as well as genes encoding photopigment biosynthesis enzymes.

[Comparison of port needle with safety device between Huber Plus (HP) and Poly PERF Safe (PPS)].

PubMed

Shimono, Chigusa; Tanaka, Atsuko; Fujita, Ai; Ishimoto, Miki; Oura, Shoji; Yamaue, Hiroki; Sato, Morio

2010-05-01

An embedded port is frequently used for outpatients with advanced cancer in central venous chemotherapy or hepatic arterial chemoinfusion. The port needle with a safety device in an ambulatory treatment center is indispensable for medical employees and patient plus family to reduce the risk of a needle puncture accident and to prevent iatrogenic infection. The port needle with safety system has been already introduced in our chemotherapy center. There are two types of port needle with safety device; Huber Plus (HP, Medicon Co., Ltd.) and POLY PERF Safe (PPS, Pyolax Device, Co., Ltd.). The comparison of the feasibility between HP and PPS was conducted by both medical employees and patients plus family using an inquiry score method. HP was highly regarded for its stability plus fixation and PPS for its usefulness in puncture and extraction of the needle. PPS was found to be preferable to HP based on the overall evaluation.

On the Measurement of Procrastination: Comparing Two Scales in Six European Countries

PubMed Central

Svartdal, Frode; Pfuhl, Gerit; Nordby, Kent; Foschi, Gioel; Klingsieck, Katrin B.; Rozental, Alexander; Carlbring, Per; Lindblom-Ylänne, Sari; Rębkowska, Kaja

2016-01-01

Procrastination is a common problem, but defining and measuring it has been subject to some debate. This paper summarizes results from students and employees (N = 2893) in Finland, Germany, Italy, Norway, Poland, and Sweden using the Pure Procrastination Scale (PPS) and the Irrational Procrastination Scale (IPS; Steel, 2010), both assumed to measure unidimensional and closely related constructs. Confirmatory factor analyses indicated inadequate configural fit for the suggested one-factor model for PPS; however, acceptable fit was observed for a three-factor model corresponding to the three different scales the PPS is based on. Testing measurement invariance over countries and students–employees revealed configural but not strong or strict invariance, indicating that both instruments are somewhat sensitive to cultural differences. We conclude that the PPS and IPS are valid measures of procrastination, and that the PPS may be particularly useful in assessing cultural differences in unnecessary delay. PMID:27630595

On the Measurement of Procrastination: Comparing Two Scales in Six European Countries.

PubMed

Svartdal, Frode; Pfuhl, Gerit; Nordby, Kent; Foschi, Gioel; Klingsieck, Katrin B; Rozental, Alexander; Carlbring, Per; Lindblom-Ylänne, Sari; Rębkowska, Kaja

2016-01-01

Procrastination is a common problem, but defining and measuring it has been subject to some debate. This paper summarizes results from students and employees (N = 2893) in Finland, Germany, Italy, Norway, Poland, and Sweden using the Pure Procrastination Scale (PPS) and the Irrational Procrastination Scale (IPS; Steel, 2010), both assumed to measure unidimensional and closely related constructs. Confirmatory factor analyses indicated inadequate configural fit for the suggested one-factor model for PPS; however, acceptable fit was observed for a three-factor model corresponding to the three different scales the PPS is based on. Testing measurement invariance over countries and students-employees revealed configural but not strong or strict invariance, indicating that both instruments are somewhat sensitive to cultural differences. We conclude that the PPS and IPS are valid measures of procrastination, and that the PPS may be particularly useful in assessing cultural differences in unnecessary delay.

Quantitative muscle ultrasound and quadriceps strength in patients with post-polio syndrome.

PubMed

Bickerstaffe, Alice; Beelen, Anita; Zwarts, Machiel J; Nollet, Frans; van Dijk, Johannes P

2015-01-01

We investigated whether muscle ultrasound can distinguish muscles affected by post-polio syndrome (PPS) from healthy muscles and whether severity of ultrasound abnormalities is associated with muscle strength. Echo intensity, muscle thickness, and isometric strength of the quadriceps muscles were measured in 48 patients with PPS and 12 healthy controls. Patients with PPS had significantly higher echo intensity and lower muscle thickness than healthy controls. In patients, both echo intensity and muscle thickness were associated independently with muscle strength. A combined measure of echo intensity and muscle thickness was more strongly related to muscle strength than either parameter alone. Quantitative ultrasound distinguishes healthy muscles from those affected by PPS, and measures of muscle quality and quantity are associated with muscle strength. Hence, ultrasound could be a useful tool for assessing disease severity and monitoring changes resulting from disease progression or clinical intervention in patients with PPS. © 2014 Wiley Periodicals, Inc.

Investigation and development of friction stir welding process for unreinforced polyphenylene sulfide and reinforced polyetheretherketone

NASA Astrophysics Data System (ADS)

Ahmed, Hossain

The joining of thermoplastics through welding, a specific form of fusion bonding, offers numerous advantages over mechanical joining. It eliminates the use of costly fasteners and has only a limited effect on the strength of the parts being joined since it does not require the introduction of holes and loading pins, and it does not create significant stress concentrations. A specific form of welding, Friction Stir Welding, was investigated for the creation of butt joints of unreinforced polyphenylene sulfide (PPS) and short carbon fiber reinforced polyetheretherketone (PEEK) plates. Friction stir welding requires a rotating pin, a shoulder arrangement, relative movement between the tool and the weld piece and a clamping mechanism to hold the weld piece in place. Analytical models and experimental results show that the heat generated by the FSW tool is insufficient to produce the heat required to weld thermoplastic materials which makes FSW of polymers different from FSW of metals. A second heat source is required for preheating the thermoplastic parts prior to welding. A resistance type surface heater was placed at the bottom of two identical weld pieces for the experiments. Two types of shoulder design i.e. a rotating shoulder and a stationary shoulder were developed. Taguchi's Design of Experiment method was utilized to investigate the welding process, where duration of heating, process temperature, tool rotational speed and tool traverse speed were used as the welding parameters. The quality of the welding process was assumed to be indicated by the weld strength. DoE revealed that one of the process parameters, tool traverse speed, had significant influence on the tensile strength of PPS samples. While PPS sample showed relatively lower tensile strength with higher traverse speed, short carbon fiber reinforced PEEK samples had higher tensile strength with higher traverse speeds. In addition to tensile tests on dog bone shaped specimen, fracture toughness tests were performed for both PPS and PEEK samples to identify the fracture toughness of these materials. Presence of un-welded section in the welded specimen due to the setup of the experiments yielded notched tensile strengths during the tensile test process. With the help of fracture toughness values of these materials, notched tensile strengths of the welded samples were compared with the notched tensile strengths or residual tensile strengths of the base materials. In this study, residual joint efficiency of PEEK samples was found higher than that of PPS samples. Additionally, notched tensile strengths of the welded samples were compared with un-notched tensile strengths of the materials. The notched tensile strengths of PPS and PEEK were found about 80% and 75% of the respective base materials. Micrographs of PEEK samples showed the presence of more voids and cracks in the weld line compared to the un-welded samples. In this study, continuous friction stir welding process has been developed for butt joining of unreinforced PPS and short carbon fiber reinforced PEEK. The process parameters and the experimental setup can be utilized to investigate the weldability of different types of thermoplastic composites and various types of joint configurations.

Effects of compound carboxylate-urea system on nano Ni-Cr/SiC composite coatings from trivalent chromium baths.

PubMed

He, Xinkuai; Hou, Bailong; Cai, Youxing; Wu, Luye

2013-03-01

The effects of compound carboxylate-urea system on the nano Ni-Cr/SiC composite coatings from trivalent chromium baths have been investigated in ultrasonic field. These results indicated that the SiC and Cr contents and the thickness of the Ni-Cr/SiC composite coatings could be obviously improved by the compound carboxylate-urea system. The steady-state polarization curves showed that the hydrogen evolution reaction (HER) could be significantly inhibited by the compound carboxylate-urea system, which was benefit to increase the SiC and Cr contents and the thickness of the composite coatings. The cyclic voltammetry (CV) curves showed that both of the Cr(III) and Ni(II) cathodic polarization could be increased in the bath containing the compound carboxylate-urea system. Thus, a compact Ni-Cr/SiC composite coating could be obtained using this technique. The surface morphology of the Ni-Cr/SiC composite coatings checked with the scanning electron micrographs (SEM) showed that the surface smoothness could be also improved and the microcracks and pinholes could be decreased due to the presence of the compound carboxylate-urea system. The phase composition of the as-posited coating was measured by the X-ray diffraction. XRD data showed that the as-posited coating was Ni-Cr/SiC composite coating. The chemical composition of the coating was investigated by energy dispersive spectrum (EDS) analysis. The result showed the Ni-Cr/SiC composite coatings with 3.8 wt.% SiC and 24.68 wt.% Cr were obtained in this study, which had best corrosion resistance according to the results of the typical potentiodynamic polarization curves of the Ni-Cr/SiC composite coatings.

An extended sequence specificity for UV-induced DNA damage.

PubMed

Chung, Long H; Murray, Vincent

2018-01-01

The sequence specificity of UV-induced DNA damage was determined with a higher precision and accuracy than previously reported. UV light induces two major damage adducts: cyclobutane pyrimidine dimers (CPDs) and pyrimidine(6-4)pyrimidone photoproducts (6-4PPs). Employing capillary electrophoresis with laser-induced fluorescence and taking advantages of the distinct properties of the CPDs and 6-4PPs, we studied the sequence specificity of UV-induced DNA damage in a purified DNA sequence using two approaches: end-labelling and a polymerase stop/linear amplification assay. A mitochondrial DNA sequence that contained a random nucleotide composition was employed as the target DNA sequence. With previous methodology, the UV sequence specificity was determined at a dinucleotide or trinucleotide level; however, in this paper, we have extended the UV sequence specificity to a hexanucleotide level. With the end-labelling technique (for 6-4PPs), the consensus sequence was found to be 5'-GCTC*AC (where C* is the breakage site); while with the linear amplification procedure, it was 5'-TCTT*AC. With end-labelling, the dinucleotide frequency of occurrence was highest for 5'-TC*, 5'-TT* and 5'-CC*; whereas it was 5'-TT* for linear amplification. The influence of neighbouring nucleotides on the degree of UV-induced DNA damage was also examined. The core sequences consisted of pyrimidine nucleotides 5'-CTC* and 5'-CTT* while an A at position "1" and C at position "2" enhanced UV-induced DNA damage. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Electrodepositing behaviors and properties of nano Fe-Ni-Cr/SiC composite coatings from trivalent chromium baths containing compound carboxylate-urea system.

PubMed

He, Xinkuai; Hou, Bailong; Cai, Youxing; Li, Chen; Jiang, Yumei; Wu, Luye

2013-06-01

The nano Fe-Ni-Cr/SiC composite coatings were prepared using pulse electrodeposition method from trivalent chromium baths containing compound carboxylate-urea system and nano SiC in ultrasonic field. The effects of the carboxylate-urea system on the nano Fe-Ni-Cr/SiC composite coatings have been investigated. These results indicated that the SiC and Cr contents and the thickness of the Fe-Ni-Cr/SiC composite coatings could be obviously improved by the compound carboxylate-urea system. The steady-state polarization curves showed that the hydrogen evolution reaction (HER) could be significantly inhibited by the compound carboxylate-urea system, which was benefit to increase the SiC and Cr contents and the thickness of the composite coatings. The cyclic voltammetry (CV) curves showed that the cathodic polarization of the matrix metal ions could be increased in the bath containing the compound carboxylate-urea system. Thus, a compact Fe-Ni-Cr/SiC composite coating could be obtained using this technique. The surface morphology of the Fe-Ni-Cr/SiC composite coatings checked with the scanning electron micrographs (SEM) showed that the surface smoothness could be also improved and the microcracks and pinholes could be decreased due to the presence of the compound carboxylate-urea system. The phase composition of the as-posited coating was measured by the X-ray diffraction (XRD). XRD data showed that the as-posited coating was Fe-Ni-Cr/SiC composite coating. The chemical composition of the coating was investigated by energy dispersive spectrum (EDS) analysis. The result showed the functional Fe-Ni-Cr/SiC composite coatings with 4.1 wt.% SiC and 25.1 wt.% Cr, and 23.9 microm thickness were obtained in this study, which had best corrosion resistance according to the results of the typical potentiodynamic polarization curves of the Fe-Ni-Cr/SiC composite coatings.

Trowelable ablative coating composition and method of use

NASA Technical Reports Server (NTRS)

Headrick, Stephen E. (Inventor); Hill, Roger L. (Inventor)

1989-01-01

A trowelable ablative coating composition is disclosed. The composition comprises an epoxy resin, an amide curing agent, glass microspheres and ground cork. A method for protecting a substrate is also disclosed. The method comprises applying the trowelable ablative coating discussed above to a substrate and curing the coating composition.

Trowelable ablative coating composition and method of use

NASA Technical Reports Server (NTRS)

Headrick, Stephen E. (Inventor); Hill, Roger L. (Inventor)

1988-01-01

A trowelable ablative coating composition is disclosed. The composition comprises an epoxy resin, an amide curing agent, glass microspheres and ground cork. A method for protecting a substrate is also disclosed. The method comprises applying the trowelable ablative coating discussed above to a substrate and curing the coating composition.

Durable polymer-aerogel based superhydrophobic coatings, a composite material

DOEpatents

Kissel, David J; Brinker, Charles Jeffrey

2014-03-04

Provided are polymer-aerogel composite coatings, devices and articles including polymer-aerogel composite coatings, and methods for preparing the polymer-aerogel composite. The exemplary article can include a surface, wherein the surface includes at least one region and a polymer-aerogel composite coating disposed over the at least one region, wherein the polymer-aerogel composite coating has a water contact angle of at least about 140.degree. and a contact angle hysteresis of less than about 1.degree.. The polymer-aerogel composite coating can include a polymer and an ultra high water content catalyzed polysilicate aerogel, the polysilicate aerogel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

Durable polymer-aerogel based superhydrophobic coatings: a composite material

DOEpatents

Kissel, David J.; Brinker, Charles Jeffrey

2016-02-02

Provided are polymer-aerogel composite coatings, devices and articles including polymer-aerogel composite coatings, and methods for preparing the polymer-aerogel composite. The exemplary article can include a surface, wherein the surface includes at least one region and a polymer-aerogel composite coating disposed over the at least one region, wherein the polymer-aerogel composite coating has a water contact angle of at least about 140.degree. and a contact angle hysteresis of less than about 1.degree.. The polymer-aerogel composite coating can include a polymer and an ultra high water content catalyzed polysilicate aerogel, the polysilicate aerogel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

Pilot production system cost/benefit analysis: Digital document storage project

NASA Technical Reports Server (NTRS)

1989-01-01

The Digital Document Storage (DDS)/Pilot Production System (PPS) will provide cost effective electronic document storage, retrieval, hard copy reproduction, and remote access for users of NASA Technical Reports. The DDS/PPS will result in major benefits, such as improved document reproduction quality within a shorter time frame than is currently possible. In addition, the DDS/PPS will provide an important strategic value through the construction of a digital document archive. It is highly recommended that NASA proceed with the DDS Prototype System and a rapid prototyping development methodology in order to validate recent working assumptions upon which the success of the DDS/PPS is dependent.

[To the issue of postreperfusion syndrome predictors in orthotopic liver transplantation (OLT)].

PubMed

Kiseleva, E A; Ushakova, I A; Kim, E F; Matveev, G P; Biriulina, N Iu; Vabishchevich, A V

2012-01-01

The aim of the study is revelation of postperfusion syndrome (pPS) predictors in orthotopic liver transplantation (OLT). Was conducted a retrospective analysis of anesthesia maintainance protocols during orthotopic liver transplantation in 261 patients aged from 6 months to 60 years. Investigated the effect of various factors on the development of PPS by the application of methods of non-parametric statistics. Significantly more frequent development of the PPS is noted in the age group from 3 to 18 years (up to 30% of patients). In recipients older than 18 years the frequency of the development of the PPS does not depend on age, with an average of 14%. The development of the PPS does not depend on the recipient sex, the nature of the pathology which served as an indication to the OTP, the initial severity of the state, type of OTP (living related donor or cadaveric transplantation, primary or re-transplantation), the transplant warm ischemia duration, use, or the lack of venous-venous bypass, metabolic status of the patient. The obtained results do not contradict to the data of foreign publications. Among parameters available for screening, predictor of PPS was not detected.

NF-κB pathways are involved in M1 polarization of RAW 264.7 macrophage by polyporus polysaccharide in the tumor microenvironment

PubMed Central

Liu, Chun-Ping; Zhang, Xian; Tan, Qing-Long; Xu, Wen-Xing; Zhou, Chang-Yuan; Luo, Min; Li, Xiong; Zeng, Xing

2017-01-01

Bladder cancer is one of the most malignant tumors closely associated with macrophages. Polyporus polysaccharide (PPS) has shown excellent efficacy in treating bladder cancer with minimal side effects. However, the molecular mechanisms underlying the effects of PPS in inhibiting bladder cancer remain unclear. In this study, we used macrophages cultured alone or with T24 human bladder cancer cell culture supernatant as study models. We found that PPS enhanced the activities of IFN-γ-stimulated RAW 264.7 macrophages, as shown by the release of inducible nitric oxide synthase (INOS), secretion of tumor necrosis factor (TNF)-α and interleukin (IL)-6, phagocytosis activity, as well as expression of M1 phenotype indicators, such as CD40, CD284 and CD86. PPS acted upstream in activation cascade of nuclear factor (NF)-κB signaling pathways by interfering with IκB phosphorylation. In addition, PPS regulated NF-κB (P65) signaling by interfering with Toll-like receptor (TLR)-4, INOS and cyclooxygenase (COX)-2. Our results indicate that PPS activates macrophages through TLR4/NF-κB signaling pathways. PMID:29155869

Femtosecond Polarization Phase Selective (PPS) High Magnetic Field Studies of Electron-Spin-Hole (ESH) Dynamics: New Tools for Ultrafast Imaging Fe-centered ESH Transfer Mechanisms Steps

NASA Astrophysics Data System (ADS)

Rupnik, Kresimir; Cooper, Benjamin; Dunne, Taylor; Gerosa, Katherine; Mercer, Kaitlyn; McGill, Stephen

In previous work, new Nanoparticle-enzyme Based Hybrids (NEBH) synthesis methods were investigated for nanoparticles of different shapes and electron energies. These hybrids can provide electromagnetic-field-driven ESH separations and transfers to desired molecular locations. Of paramount biomedical interest are the activity centers (including Fe-clusters) in proteins that perform their intended function and help synthesize other molecules. In this work we discuss results of our recent in situ ESH dynamics measurements: we use <15fs (Vitara) PPS broad band pulses and ultrahigh, 25T, magnetic fields from Split-helix magnet at NHMFL. Work included multi-spectral domain PPS harmonic generations and PPS sum frequency generations. Model compounds, including cytochromes, were used for testing and calibrations and previously studied Fe-S enzymes were prepared for measurements. While PPS opto-magnetic methods are known for their insight into electronic structure, our femtosecond measurements can provide ultrafast dynamic imaging of ESH mechanisms decision making steps. UF-PPS Project, performed in part at NHMFL, supported by NSF CA No. DMR-1157490, and 0654118 and U.S. DOE.

Use of transcriptomic data for extending a model of the AppA/PpsR system in Rhodobacter sphaeroides.

PubMed

Pandey, Rakesh; Armitage, Judith P; Wadhams, George H

2017-12-28

Photosynthetic (PS) gene expression in Rhodobacter sphaeroides is regulated in response to changes in light and redox conditions mainly by PrrB/A, FnrL and AppA/PpsR systems. The PrrB/A and FnrL systems activate the expression of them under anaerobic conditions while the AppA/PpsR system represses them under aerobic conditions. Recently, two mathematical models have been developed for the AppA/PpsR system and demonstrated how the interaction between AppA and PpsR could lead to a phenotype in which PS genes are repressed under semi-aerobic conditions. These models have also predicted that the transition from aerobic to anaerobic growth mode could occur via a bistable regime. However, they lack experimentally quantifiable inputs and outputs. Here, we extend one of them to include such quantities and combine all relevant micro-array data publically available for a PS gene of this bacterium and use that to parameterise the model. In addition, we hypothesise that the AppA/PpsR system alone might account for the observed trend of PS gene expression under semi-aerobic conditions. Our extended model of the AppA/PpsR system includes the biological input of atmospheric oxygen concentration and an output of photosynthetic gene expression. Following our hypothesis that the AppA/PpsR system alone is sufficient to describe the overall trend of PS gene expression we parameterise the model and suggest that the rate of AppA reduction in vivo should be faster than its oxidation. Also, we show that despite both the reduced and oxidised forms of PpsR binding to the PS gene promoters in vitro, binding of the oxidised form as a repressor alone is sufficient to reproduce the observed PS gene expression pattern. Finally, the combination of model parameters which fit the biological data well are broadly consistent with those which were previously determined to be required for the system to show (i) the repression of PS genes under semi-aerobic conditions, and (ii) bistability. We found that despite at least three pathways being involved in the regulation of photosynthetic genes, the AppA/PpsR system alone is capable of accounting for the observed trends in photosynthetic gene expression seen at different oxygen levels.

Private Practitioners' Perspectives on Their Involvement With the Tuberculosis Control Programme in a Southern Indian State.

PubMed

Salve, Solomon; Sheikh, Kabir; Porter, John Dh

2016-05-08

Public and private health sectors both play a crucial role in the health systems of low- and middle-income countries (LMICs). The tuberculosis (TB) control strategy in India encourages the public sector to actively partner with private practitioners (PPs) to improve the quality of front line service delivery. However, ensuring effective and sustainable involvement of PPs constitutes a major challenge. This paper reports the findings from an empirical study focusing on the perspectives and experiences of PPs towards their involvement in TB control programme in India. The study was carried out between November 2010 and December 2011 in a district of a Southern Indian State and utilised qualitative methodologies, combining observations and in-depth interviews with 21 PPs from different medical systems. The collected data was coded and analysed using thematic analysis. PPs perceived themselves to be crucial healthcare providers, with different roles within the public-private mix (PPM) TB policy. Despite this, PPs felt neglected and undervalued in the actual process of implementation of the PPM-TB policy. The entire process was considered to be government driven and their professional skills and knowledge of different medical systems remained unrecognised at the policy level, and weakened their relationship and bond with the policy and with the programme. PPs had contrasting perceptions about the different components of the TB programme that demonstrated the public sector's dominance in the overall implementation of the DOTS strategy. Although PPs felt responsible for their TB patients, they found it difficult to perceive themselves as 'partners with the TB programme.' Public-private partnerships (PPPs) are increasingly utilized as a public health strategy to strengthen health systems. These policies will fail if the concerns of the PPs are neglected. To ensure their long-term involvement in the programme the abilities of PPs and the important perspectives from other Indian medical systems need to be recognised and supported. © 2016 The Author(s); Published by Kerman University of Medical Sciences. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The Effect of Titanium Dioxide (TiO2) Nanoparticles on Hydroxyapatite (HA)/TiO2 Composite Coating Fabricated by Electrophoretic Deposition (EPD)

NASA Astrophysics Data System (ADS)

Amirnejad, M.; Afshar, A.; Salehi, S.

2018-05-01

Composite coatings of Hydroxyapatite (HA) with ceramics, polymers and metals are used to modify the surface structure of implants. In this research, HA/TiO2 composite coating was fabricated by electrophoretic deposition (EPD) on 316 stainless steel substrate. HA/TiO2 composite coatings with 5, 10 and 20 wt.% of TiO2, deposited at 40 V and 90 s as an optimum condition. The samples coated at this condition led to an adherent, continuous and crack-free coating. The influence of TiO2 content was studied by performing different characterization methods such as scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), corrosion resistance in simulated body fluid (SBF), coating's dissolution rate in physiological solution and bond strength to the substrate. The results showed that the higher amount of TiO2 in the composite coating led to increase in bond strength of coating to stainless steel substrate from 3 MPa for HA coating to 5.5 MPa for HA-20 wt.% TiO2 composite coating. In addition, it caused to reduction of corrosion current density of samples in the SBF solution from 18.92 μA/cm2 for HA coating to 6.35 μA/cm2 for HA-20 wt.% TiO2 composite coating.

The Effect of Titanium Dioxide (TiO2) Nanoparticles on Hydroxyapatite (HA)/TiO2 Composite Coating Fabricated by Electrophoretic Deposition (EPD)

NASA Astrophysics Data System (ADS)

Amirnejad, M.; Afshar, A.; Salehi, S.

2018-04-01

Composite coatings of Hydroxyapatite (HA) with ceramics, polymers and metals are used to modify the surface structure of implants. In this research, HA/TiO2 composite coating was fabricated by electrophoretic deposition (EPD) on 316 stainless steel substrate. HA/TiO2 composite coatings with 5, 10 and 20 wt.% of TiO2, deposited at 40 V and 90 s as an optimum condition. The samples coated at this condition led to an adherent, continuous and crack-free coating. The influence of TiO2 content was studied by performing different characterization methods such as scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), corrosion resistance in simulated body fluid (SBF), coating's dissolution rate in physiological solution and bond strength to the substrate. The results showed that the higher amount of TiO2 in the composite coating led to increase in bond strength of coating to stainless steel substrate from 3 MPa for HA coating to 5.5 MPa for HA-20 wt.% TiO2 composite coating. In addition, it caused to reduction of corrosion current density of samples in the SBF solution from 18.92 μA/cm2 for HA coating to 6.35 μA/cm2 for HA-20 wt.% TiO2 composite coating.

Nacre biomimetic design--a possible approach to prepare low infrared emissivity composite coatings.

PubMed

Zhang, Weigang; Xu, Guoyue; Ding, Ruya; Duan, Kaige; Qiao, Jialiang

2013-01-01

Mimicking the highly organized brick-and-mortar structure of nacre, a kind of nacre-like organic-inorganic composite material of polyurethane (PU)/flaky bronze composite coatings with low infrared emissivity was successfully designed and prepared by using PU and flaky bronze powders as adhesives and pigments, respectively. The infrared emissivity and microstructure of the coatings were systematically investigated by infrared emissometer and scanning electron microscopy, respectively, and the cause of low infrared emissivity of the coatings was discussed by using the theories of one-dimensional photonic structure. The results show that the infrared emissivity of the nacre-like PU/flaky bronze composite coatings can be as low as 0.206 at the bronze content of 60 wt. %, and it is significantly lower than the value of PU/sphere bronze composite coatings. Microstructure observation illustrated that the nacre-like PU/flaky bronze composite coatings have similar one-dimensional photonic structural characteristics. The low infrared emissivity of PU/flaky bronze composite coatings is derived from the similar one-dimensional photonic structure in the coatings. Copyright © 2012 Elsevier B.V. All rights reserved.

Phase Stability and Thermal Conductivity of Composite Environmental Barrier Coatings on SiC/SiC Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Benkel, Samantha; Zhu, Dongming

2011-01-01

Advanced environmental barrier coatings are being developed to protect SiC/SiC ceramic matrix composites in harsh combustion environments. The current coating development emphasis has been placed on the significantly improved cyclic durability and combustion environment stability in high-heat-flux and high velocity gas turbine engine environments. Environmental barrier coating systems based on hafnia (HfO2) and ytterbium silicate, HfO2-Si nano-composite bond coat systems have been processed and their stability and thermal conductivity behavior have been evaluated in simulated turbine environments. The incorporation of Silicon Carbide Nanotubes (SiCNT) into high stability (HfO2) and/or HfO2-silicon composite bond coats, along with ZrO2, HfO2 and rare earth silicate composite top coat systems, showed promise as excellent environmental barriers to protect the SiC/SiC ceramic matrix composites.

MST's Programmable Power Supplies: Bt Update, Bp Prototype

NASA Astrophysics Data System (ADS)

Holly, D. J.; Chapman, B. E.; McCollam, K. J.; Morin, J. C.; Thomas, M. A.

2013-10-01

MST's toroidal field programmable power supply (Bt PPS) has now been in operation for several years and has provided important new capabilities. One of the primary goals for the Bt PPS is the partial optimization of inductive current profile control, involving control of the poloidal electric field. The Bt PPS has achieved fluctuation reduction over MST's entire range of Ip. At the largest Ip, the Bt PPS achieves fluctuation reduction with a smaller poloidal electric field than the previous passive system, implying that substantially longer periods of current profile control may be possible. The Bt PPS has also been used to produce Ohmic tokamak plasmas in MST. With an applied toroidal field of 0.135 T, and q(a) > 2, the estimated energy confinement time is roughly consistent with neo-Alcator scaling. Driving q(a) < 2 with larger Ip, the confinement time degrades, but the discharge duration does not terminate prematurely. To fully optimize current profile control and to test MST operational limits, a PPS is also needed for the Bp circuit. Currently in prototype stage, the Bp PPS will feature a number of innovations to increase its flexibility and performance. Isolated charging, control, and monitor systems will eliminate charging relays, reduce coupling between modules, and minimize capacitor heating. Seven-level pulse width modulation will reduce output ripple and switching losses. Solid state shorting bars will eliminate shorting relays and minimize wiring. A balanced switching algorithm will minimize capacitive noise generation. Work supported by U. S. D. o. E.

Functional impairment related to painful physical symptoms in patients with generalized anxiety disorder with or without comorbid major depressive disorder: post hoc analysis of a cross-sectional study

PubMed Central

2011-01-01

Background Generalized anxiety disorder (GAD) is the most frequent anxiety disorder in primary care patients. It is known that painful physical symptoms (PPS) are associated with GAD, regardless the presence of comorbid major depressive disorder (MDD). However the specific role of such symptoms in patients' functional impairment is not well understood. The objective of the present study is to assess functional impairment related to the presence of PPS in patients with GAD. Methods This is a post hoc analysis of a cross-sectional study. Functioning, in the presence (overall pain score >30; Visual Analog Scale) or absence of PPS, was assessed using the Sheehan Disability Scale (SDS) in three groups of patients; 1) GAD and comorbid MDD (GAD+MDD+), 2) GAD without comorbid MDD (GAD+MDD-), 3) controls (GAD-MDD-). ANCOVA models were used. Results Of those patients with GAD+MDD+ (n = 559), 436 (78.0%) had PPS, compared with GAD+MDD- (249 of 422, 59%) and controls (95 of 336, 28.3%). Functioning worsened in both GAD groups in presence of PPS (SDS least squares mean total score: 16.1 vs. 9.8, p < 0.0001, GAD+MDD+; 14.3 vs. 8.2, p < 0.0001, GAD+MDD-). The presence of PPS was significantly associated with less productivity. Conclusions Functional impairment related to the presence of PPS was relevant. Clinical implications should be considered. PMID:21510887

Interoceptive influences on peripersonal space boundary.

PubMed

Ardizzi, Martina; Ferri, Francesca

2018-08-01

Integration of body-related signals within the peripersonal space (PPS) contributes to bodily self-awareness. Whereas several studies have shown how individual PPS extension is shaped by external factors, e.g. during interactions with people and objects, no studies have looked at interoceptive influences on PPS extension. We exposed participants to an audio-tactile interaction task, to measure their PPS boundary (Session 1), and to a heartbeat counting task and a time estimation task, to specifically assess their interoceptive accuracy (Session 2). Participants' traits of private self-consciousness and social anxiety were also evaluated, to account for their possible effect on the relation between interoception and PPS representation. We found that higher interoceptive accuracy specifically predicts narrower PPS boundary. Moreover, this relation is moderated by individual traits of private self-consciousness, but not social anxiety. Extending the concept of interoceptive influences on exteroceptive body representations to PPS, our results, first, support the idea that a dynamic balance between intero-exteroceptive processing might represent a general principle underlying bodily self-awareness; second, they shed light on how interoception may affect also the way we interface with the external world. Finally, showing that, in order for interoceptive accuracy to be effective on the intero-exteroceptive balance, it is important that individuals tend to focus on inner sensations and feelings, our results suggest that a comprehensive intero-exteroceptive model of bodily self-awareness should be (at least) a three-dimensional model that includes individual self-consciousness traits. Copyright © 2018 Elsevier B.V. All rights reserved.

A new method to precisely control the depth of percutaneous screws into the pedicle by counting the rotation number of the screw with low radiation exposure: technical note.

PubMed

Li, Xu; Zhang, Feng; Zhang, Wenzhi; Shang, Xifu; Han, Jintao; Liu, Pengfei

2017-03-01

Technique note. To report a new method for precisely controlling the depth of percutaneous pedicle screws (PPS)-without radiation exposure to surgeons and less fluoroscopy exposure to patients than with conventional methods. PPS is widely used in minimal invasive spine surgery; the advantages include reduced muscle damage, pain, and hospital stays. However, placement of PPS demands repeated checking with fluoroscopy. Thus, radiation exposure is considerable for both surgeons and patients. The PPS depth was determined by counting rotations of the screws. The distance between screw threads can be measured for particular screws; thus, full rotations of the PPS results in the screw advancing in the pedicle the distance between screw threads. To fully insert screws into the pedicle, the number of full rotations is equal to the number of threads in the PPS. We applied this technique in 58 patients with thoracolumbar fracture. The position and depth of the screws was checked during the operation with the C-arm and after operation by anteroposterior X-ray film or computed tomography. No additional procedures were required to correct the screws; we observed no neurological deficits or malpositioning of the screws. In the screw placement procedure, the radiation exposure for surgeons is zero, and the patient is well protected from extensive radiation exposure. This method of counting rotation of screws is a safe way to precisely determine the depth of PPS in the placement procedure. IV.

Forecasting E > 50-MeV proton events with the proton prediction system (PPS)

NASA Astrophysics Data System (ADS)

Kahler, Stephen W.; White, Stephen M.; Ling, Alan G.

2017-11-01

Forecasting solar energetic (E > 10-MeV) particle (SEP) events is an important element of space weather. While several models have been developed for use in forecasting such events, satellite operations are particularly vulnerable to higher-energy (≥50-MeV) SEP events. Here we validate one model, the proton prediction system (PPS), which extends to that energy range. We first develop a data base of E ≥ 50-MeV proton events >1.0 proton flux units (pfu) events observed on the GOES satellite over the period 1986-2016. We modify the PPS to forecast proton events at the reduced level of 1 pfu and run PPS for four different solar input parameters: (1) all ≥M5 solar X-ray flares; (2) all ≥200 sfu 8800-MHz bursts with associated ≥M5 flares; (3) all ≥500 sfu 8800-MHz bursts; and (4) all ≥5000 sfu 8800-MHz bursts. The validation contingency tables and skill scores are calculated for all groups and used as a guide to use of the PPS. We plot the false alarms and missed events as functions of solar source longitude, and argue that the longitude-dependence employed by PPS does not match modern observations. Use of the radio fluxes as the PPS driver tends to result in too many false alarms at the 500 sfu threshold, and misses more events than the soft X-ray predictor at the 5000 sfu threshold.

Preparation and bioactive properties of chitosan and casein phosphopeptides composite coatings for orthopedic implants.

PubMed

Qin, Liguo; Dong, Huanhuan; Mu, Ziqing; Zhang, Yali; Dong, Guangneng

2015-11-20

Using the layer-by-layer deposition method, functional chitosan/casein phospopeptides (CS/CPP) composite coatings were produced on Co-Cr-Mo alloy. The CS/CPP composite coatings had the dendritic topography, and were quite hydrophilic. Zeta potential measurements showed the composite coatings were negative charged at neural pH. XPS results indicated that the CS/CPP composite coatings were covalently bond to the substrate. When MC3T3-E1 cells were seeded on the CS/CPP composite coatings, no cytotoxicity was observed. The bone morphogenetic protein-2 (BMP-2) mRNA expression was significantly up-regulated in MC3T3-E1 cells cultured on the composite coatings and it was twice as much as that of cells cultured on the bare substrate. The expression of osteoprotegerin (OPG) mRNA and the ratio of OPG/receptor activator of nuclear factor-κB ligand (RNAKL) mRNA were increased 5-fold and 55-fold, respectively. These results suggested the CS/CPP composite coatings may have potential application in cobalt matrix orthopaedic implants. Copyright © 2015 Elsevier Ltd. All rights reserved.

Thermal barrier coatings with (Al2O3-Y2O3)/(Pt or Pt-Au) composite bond coat and 8YSZ top coat on Ni-based superalloy

NASA Astrophysics Data System (ADS)

Yao, Junqi; He, Yedong; Wang, Deren; Peng, Hui; Guo, Hongbo; Gong, Shengkai

2013-12-01

Developing new bond coat has been acknowledged as an effective way to extend the service life of thermal barrier coating (TBC) during high temperature. In this study, novel thermal barrier coating system, which is composed with an (Al2O3-Y2O3)/(Pt or Pt-Au) composite bond coat and a YSZ top coat on Ni-based superalloy, has been prepared by magnetron sputtering and EB-PVD, respectively. It is demonstrated, from the cyclic oxidation tests in air at 1100 °C for 200 h, that the YSZ top coat and alloy substrate can be bonded together effectively by the (Al2O3-Y2O3)/(Pt or Pt-Au) composite coating, showing excellent resistance to oxidation, cracking and buckling. These beneficial results can be attributed to the sealing effect of such composite coating, by which the alloy substrate can be protected from oxidation and the interdiffusion between the bond coat and alloy substrate can be avoided; and the toughening effect of noble metals and composite structure of bond coat, by which the micro-cracks propagation can be inhibited and the stress in bond coat can be relaxed. This ceramic/noble metal composite coating can be a considerable structure which would has great application prospect in the TBC.

Multi-PAS domain-mediated protein oligomerization of PpsR from Rhodobacter sphaeroides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heintz, Udo; Meinhart, Anton; Winkler, Andreas, E-mail: andreas.winkler@mpimf-heidelberg.mpg.de

2014-03-01

Crystal structures of two truncated variants of the transcription factor PpsR from R. sphaeroides are presented that enabled the phasing of a triple PAS domain construct. Together, these structures reveal the importance of α-helical PAS extensions for multi-PAS domain-mediated protein oligomerization and function. Per–ARNT–Sim (PAS) domains are essential modules of many multi-domain signalling proteins that mediate protein interaction and/or sense environmental stimuli. Frequently, multiple PAS domains are present within single polypeptide chains, where their interplay is required for protein function. Although many isolated PAS domain structures have been reported over the last decades, only a few structures of multi-PAS proteinsmore » are known. Therefore, the molecular mechanism of multi-PAS domain-mediated protein oligomerization and function is poorly understood. The transcription factor PpsR from Rhodobacter sphaeroides is such a multi-PAS domain protein that, in addition to its three PAS domains, contains a glutamine-rich linker and a C-terminal helix–turn–helix DNA-binding motif. Here, crystal structures of two N-terminally and C-terminally truncated PpsR variants that comprise a single (PpsR{sub Q-PAS1}) and two (PpsR{sub N-Q-PAS1}) PAS domains, respectively, are presented and the multi-step strategy required for the phasing of a triple PAS domain construct (PpsR{sub ΔHTH}) is illustrated. While parts of the biologically relevant dimerization interface can already be observed in the two shorter constructs, the PpsR{sub ΔHTH} structure reveals how three PAS domains enable the formation of multiple oligomeric states (dimer, tetramer and octamer), highlighting that not only the PAS cores but also their α-helical extensions are essential for protein oligomerization. The results demonstrate that the long helical glutamine-rich linker of PpsR results from a direct fusion of the N-cap of the PAS1 domain with the C-terminal extension of the N-domain that plays an important role in signal transduction.« less

Brain volume and fatigue in patients with postpoliomyelitis syndrome.

PubMed

Trojan, Daria A; Narayanan, Sridar; Francis, Simon J; Caramanos, Zografos; Robinson, Ann; Cardoso, Mauro; Arnold, Douglas L

2014-03-01

Acute paralytic poliomyelitis is associated with encephalitis. Early brain inflammation may produce permanent neuronal injury with brain atrophy, which may result in symptoms such as fatigue. Brain volume has not been assessed in postpoliomyelitis syndrome (PPS). To determine whether brain volume is decreased compared with that in normal controls, and whether brain volume is associated with fatigue in patients with PPS. A cross-sectional study. Tertiary university-affiliated hospital postpolio and multiple sclerosis (MS) clinics. Forty-nine ambulatory patients with PPS, 28 normal controls, and 53 ambulatory patients with MS. We studied the brains of all study subjects with magnetic resonance imaging by using a 1.5 T Siemens Sonata machine. The subjects completed the Fatigue Severity Scale. Multivariable linear regression models were computed to evaluate the contribution of PPS and MS compared with controls to explain brain volume. Normalized brain volume (NBV) was assessed with the automated program Structured Image Evaluation, using Normalization, of Atrophy method from the acquired magnetic resonance images. This method may miss brainstem atrophy. Technically adequate NBV measurements were available for 42 patients with PPS, 27 controls, and 49 patients with MS. The mean (standard deviation) age was 60.9 ± 7.6 years for patients with PPS, 47.0 ± 14.6 years for controls, and 46.2 ± 9.4 years for patients with MS. In a multivariable model adjusted for age and gender, NBV was not significantly different in patients with PPS compared with that in controls (P = .28). As expected, when using a similar model for patients with MS, NBV was significantly decreased compared with that in controls (P = .006). There was no significant association between NBV and fatigue in subjects with PPS (Spearman ρ = 0.23; P = .19). No significant whole-brain atrophy was found, and no association of brain volume with fatigue in PPS. Brain atrophy was confirmed in MS. It is possible that brainstem atrophy was not recognized by this study. Copyright © 2014 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Two-layer thermal barrier coating. I - Effects of composition and temperature on oxidation behavior and failure

NASA Technical Reports Server (NTRS)

Stecura, Stephan

1989-01-01

The effects of 21 bond and 2 ceramic coating compositions on the specific mass gain, internal crack location at failure, and life of a two-layer thermal barrier coating (TBC) were studied by cyclic testing in a furnace. MAR-M 200 + Hf alloy specimens were completely coated with bond and thermal barrier (ceramic) coatings. Both coatings were applied by air plasma spray deposition. Cyclic test data were obtained at 1110, 1160, and 1220 deg C. The data show that the specific mass gain and the TBC life are significantly affected by the composition of the bond coating and the temperature and only slightly affected by the composition of the ceramic coating.

Spin-coating: A new approach for improving dispersion of cellulose nanocrystals and mechanical properties of poly (lactic acid) composites.

PubMed

Shojaeiarani, Jamileh; Bajwa, Dilpreet S; Stark, Nicole M

2018-06-15

This study systematically evaluated the influence of masterbatch preparation techniques, solvent casting and spin-coating methods, on composite properties. Composites were manufactured by combining CNCs masterbatches and PLA resin using twin screw extruder followed by injection molding. Different microscopy techniques were used to investigate the dispersion of CNCs in masterbatches and composites. Thermal, thermomechanical, and mechanical properties of composites were evaluated. Scanning electron microscopy (SEM) images showed superior dispersion of CNCs in spin-coated masterbatches compared to solvent cast masterbatches. At lower CNCs concentrations, both SEM and optical microscope images confirmed more uniform CNCs dispersion in spin-coated composites than solvent cast samples. Degree of crystallinity of PLA exhibited a major enhancement by 147% and 380% in solvent cast and spin-coated composites, respectively. Spin-coated composites with lower CNCs concentration exhibited a noticeable improvement in mechanical properties. However, lower thermal characteristics in spin-coated composites were observed, which could be attributed to the residual solvents in masterbatches. Copyright © 2018 Elsevier Ltd. All rights reserved.

Coatings for directional eutectics. [cyclic furnace oxidation tests

NASA Technical Reports Server (NTRS)

Jackson, M. R.; Rairden, J. R.; Hampton, L. V.

1974-01-01

Coating compositions were evaluated for oxidation protection of directionally solidified composite alloy NiTaC-13. These coatings included three NiCrAlY compositions (30-5-1, 25-10-1 and 20-15-1), two FeCrAlY compositions (30-5-1 and 25-10-1), a CoCrAlY composition (25-10-1), and one duplex coating, Ni-35Cr + Al. Duplicate pin samples of each composition were evaluated using two cyclic furnace oxidation tests of 100 hours at 871 C and 500 hours at 1093 C. The two best coatings were Ni-20Cr-15Al-lY and Ni-35Cr + Al. The two preferred coatings were deposited on pins and were evaluated in detail in .05 Mach cyclic burner rig oxidation to 1093 C. The NiCrAlY coating was protective after 830 hours of cycling, while the duplex coating withstood 630 hours. Test bars were coated and cycled for up to 500 hours. Tensile tests indicated no effect of coatings on strength. In 871 C air stress rupture, a degradation was observed for coated relative to bare material. The cycled NiCrAlY coating offered excellent protection with properties superior to the bare cycled NiTaC-13 in 1093 C air stress rupture.

Mechanical, degradation and cytocompatibility properties of magnesium coated phosphate glass fibre reinforced polycaprolactone composites.

PubMed

Liu, Xiaoling; Hasan, Muhammad S; Grant, David M; Harper, Lee T; Parsons, Andrew J; Palmer, Graham; Rudd, Chris D; Ahmed, Ifty

2014-11-01

Retention of mechanical properties of phosphate glass fibre reinforced degradable polyesters such as polycaprolactone and polylactic acid in aqueous media has been shown to be strongly influenced by the integrity of the fibre/polymer interface. A previous study utilising 'single fibre' fragmentation tests found that coating with magnesium improved the fibre and matrix interfacial shear strength. Therefore, the aim of this study was to investigate the effects of a magnesium coating on the manufacture and characterisation of a random chopped fibre reinforced polycaprolactone composite. Short chopped strand non-woven phosphate glass fibre mats were sputter coated with degradable magnesium to manufacture phosphate glass fibre/polycaprolactone composites. The degradation behaviour (water uptake, mass loss and pH change of the media) of these polycaprolactone composites as well as of pure polycaprolactone was investigated in phosphate buffered saline. The Mg coated fibre reinforced composites revealed less water uptake and mass loss during degradation compared to the non-coated composites. The cations released were also explored and a lower ion release profile for all three cations investigated (namely Na(+), Mg(2+) and Ca(2+)) was seen for the Mg coated composite samples. An increase of 17% in tensile strength and 47% in tensile modulus was obtained for the Mg coated composite samples. Both flexural and tensile properties were investigated and a higher retention of mechanical properties was obtained for the Mg coated fibre reinforced composite samples up to 10 days immersion in PBS. Cytocompatibility study showed both composite samples (coated and non-coated) had good cytocompatibility with human osteosarcoma cell line. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Intermolecular Structural Change for Thermoswitchable Polymeric Photosensitizer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Wooram; Park, Sin-Jung; Cho, Soojeong

2016-08-17

A switchable photosensitizer (PS), which can be activated at a spe-cific condition beside light, has tremendous advantages for photo-dynamic therapy (PDT). Herein, we developed a thermo-switchable polymeric photosensitizer (T-PPS) by conjugating PS (Pheophor-bide-a, PPb-a) to a temperature-responsive polymer backbone of biocompatible hydroxypropyl cellulose (HPC). Self-quenched PS molecules linked in close proximity by pi-pi stacking in T-PPS were easily transited to an active monomeric state by the tempera-ture induced phase transition of polymer backbones. The tempera-ture responsive inter-molecular interaction changes of PS molecules in T-PPS were demonstrated in synchrotron small-angle X-ray scattering (SAXS) and UV-Vis spectrophotometer analysis. The T-PPS allowed switchablemore » activation and synergistically enhanced cancer cell killing effect at the hyperthermia temperature (45 °C). Our developed T-PPS has the considerable potential not only as a new class of photomedicine in clinics but also as a biosensor based on temperature responsiveness.« less

Circadian variation of fatigue in both patients with paralytic poliomyelitis and post-polio syndrome.

PubMed

Viana, Celiana Figueiredo; Pradella-Hallinan, Márcia; Quadros, Abrahão Augusto Juviniano; Marin, Luis Fabiano; Oliveira, Acary Souza Bulle

2013-07-01

It was to evaluate the degree of fatigue in patients with paralytic poliomyelitis (PP) and with post-polio syndrome (PPS), and correlate it with parameters of sleep and the circadian cycle. Thirty patients, 17 female (56.7%), participated in the study: they answered the Revised Piper Fatigue Scale and performed a nocturnal polysomnographic study. Eleven had PP (mean age±standard deviation of 47.9±6.4 years), and 19 had PPS (mean age±standard deviation of 46.4±5.6 years). Our study showed that fatigue was worse in the afternoon in the PP Group and had a progressive increase throughout the day in the PPS Group. We also observed compromised quality of sleep in both groups, but no statically significant difference was found in the sleep parameters measured by polysomnography. Fatigue has a well-defined circadian variation, especially in PPS Group. Poor sleep quality is associated with fatigue and, therefore, sleep disturbances should be evaluated and treated in this group of PPS.

Post-Polio Syndrome and the Late Effects of Poliomyelitis: Part 1. Pathogenesis, Biomechanical Considerations, Diagnosis, and Investigations.

PubMed

Lo, Julian K; Robinson, Lawrence R

2018-05-12

Post-Polio Syndrome (PPS) is characterized by new muscle weakness and/or muscle fatigability that occurs many years following the initial poliomyelitis illness. There are many theories that exist on the pathogenesis of PPS, which remains incompletely understood. In contrast, the Late Effects of Poliomyelitis are often a consequence of biomechanical alterations that occur as a result of polio-related surgeries, musculoskeletal deformities or weakness. Osteoporosis and fractures of the polio-involved limbs are common. A comprehensive clinical evaluation with appropriate investigations is essential to fulfilling the established PPS diagnostic criteria. PPS is a diagnosis of exclusion, in which a key clinical feature required for the diagnosis is new muscle weakness and/or muscle fatigability that is persistent for at least one year. Electromyographic and muscle biopsy findings including evidence of ongoing denervation cannot reliably distinguish between patients with or without PPS. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

A ternary AppA-PpsR-DNA complex mediates light regulation of photosynthesis-related gene expression.

PubMed

Winkler, Andreas; Heintz, Udo; Lindner, Robert; Reinstein, Jochen; Shoeman, Robert L; Schlichting, Ilme

2013-07-01

The anoxygenic phototrophic bacterium Rhodobacter sphaeroides uses different energy sources, depending on environmental conditions including aerobic respiration or, in the absence of oxygen, photosynthesis. Photosynthetic genes are repressed at high oxygen tension, but at intermediate levels their partial expression prepares the bacterium for using light energy. Illumination, however, enhances repression under semiaerobic conditions. Here, we describe molecular details of two proteins mediating oxygen and light control of photosynthesis-gene expression: the light-sensing antirepressor AppA and the transcriptional repressor PpsR. Our crystal structures of both proteins and their complex and hydrogen/deuterium-exchange data show that light activation of AppA-PpsR2 affects the PpsR effector region within the complex. DNA binding studies demonstrate the formation of a light-sensitive ternary AppA-PpsR-DNA complex. We discuss implications of these results for regulation by light and oxygen, highlighting new insights into blue light-mediated signal transduction.

Carbon foam/hydroxyapatite coating for carbon/carbon composites: Microstructure and biocompatibility

NASA Astrophysics Data System (ADS)

Zhang, Leilei; Li, Hejun; Li, Kezhi; Zhang, Shouyang; Lu, Jinhua; Li, Wei; Cao, Sheng; Wang, Bin

2013-12-01

To improve the surface biocompatibility of carbon/carbon composites, a carbon foam/hydroxyapatite coating was applied using a combination method of slurry procedure and ultrasound-assisted electrochemical deposition procedure. The morphology, microstructure and chemical composition of the coating were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray diffraction. The biocompatibility of the carbon foam/hydroxyapatite coating was investigated by osteoblast-like MG63 cell culture tests. The results showed that the carbon foam could provide a large number of pores on the surface of carbon/carbon composites. The hydroxyapatite crystals could infiltrate into the pores and form the carbon foam/hydroxyapatite coating. The coating covered the carbon/carbon composites fully and uniformly with slice morphology. The cell response tests showed that the MG63 cells on carbon foam/hydroxyapatite coating had a better cell adhesion and cell proliferation than those on uncoated carbon/carbon composites. The carbon foam/hydroxyapatite coatings were cytocompatible and were beneficial to improve the biocompatibility. The approach presented here may be exploited for fabrication of carbon/carbon composite implant surfaces.

Microanalysis characterization of bioactive protein-bound polysaccharides produced by Amanita ponderosa cultures.

PubMed

Salvador, Cátia; Martins, M Rosário; Caldeira, A Teresa

2015-02-01

Different compounds of edible mushrooms are responsible for their bioactivity. The ability to synthesize polysaccharides, namely protein-polysaccharide (PPS) complexes, is related to the antioxidant capacity of these compounds and present great interest in preventing a number of diseases, including cancer, cardiovascular and auto-immune diseases, and accelerated aging. Amanita ponderosa are wild edible mushrooms that grow in Mediterranean "montado" areas [Portuguese name given to cork oak (Quercus suber) and holm oak (Quercus ilex) forests]. The aim of this study was to evaluate the production of PPS complexes obtained from A. ponderosa cultures using a new microanalytical approach to quickly and easily monitor the production process. Microanalysis using Fourier-transform infrared using attenuated total reflection and Raman spectroscopy of PPS samples showed spectra compatible with identification of this type of compound in culture extracts. PPS separated by size-exclusion chromatography showed seven main complexes. Molecular weights of the main PPS complexes isolated from cultures ranged between 1.5 and 20 kDa and did not present toxicity against Artemia salina, demonstrating the potential of A. ponderosa as a source of biologically active compounds with nutraceutical value. Application of this microanalytical approach to monitoring the production of PPS compounds can be successfully applied in biotechnological processes.

Audio-visual sensory deprivation degrades visuo-tactile peri-personal space.

PubMed

Noel, Jean-Paul; Park, Hyeong-Dong; Pasqualini, Isabella; Lissek, Herve; Wallace, Mark; Blanke, Olaf; Serino, Andrea

2018-05-01

Self-perception is scaffolded upon the integration of multisensory cues on the body, the space surrounding the body (i.e., the peri-personal space; PPS), and from within the body. We asked whether reducing information available from external space would change: PPS, interoceptive accuracy, and self-experience. Twenty participants were exposed to 15 min of audio-visual deprivation and performed: (i) a visuo-tactile interaction task measuring their PPS; (ii) a heartbeat perception task measuring interoceptive accuracy; and (iii) a series of questionnaires related to self-perception and mental illness. These tasks were carried out in two conditions: while exposed to a standard sensory environment and under a condition of audio-visual deprivation. Results suggest that while PPS becomes ill defined after audio-visual deprivation, interoceptive accuracy is unaltered at a group-level, with some participants improving and some worsening in interoceptive accuracy. Interestingly, correlational individual differences analyses revealed that changes in PPS after audio-visual deprivation were related to interoceptive accuracy and self-reports of "unusual experiences" on an individual subject basis. Taken together, the findings argue for a relationship between the malleability of PPS, interoceptive accuracy, and an inclination toward aberrant ideation often associated with mental illness. Copyright © 2018. Published by Elsevier Inc.

Determination of pharmaceutical residues and assessment of their removal efficiency at the Daugavgriva municipal wastewater treatment plant in Riga, Latvia.

PubMed

Reinholds, I; Muter, O; Pugajeva, I; Rusko, J; Perkons, I; Bartkevics, V

2017-01-01

Pharmaceutical products (PPs) belong to emerging contaminants that may accumulate along with other chemical pollutants in wastewaters (WWs) entering industrial and/or urban wastewater treatment plants (WWTPs). In the present study, the technique of ultra-high-performance liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (Orbitrap-HRMS) was applied for the analysis of 24 multi-class PPs in WW samples collected at different technological stages of Daugavgriva WWTP located in Riga, Latvia. Caffeine and acetaminophen levels in the range of 7,570-11,403 ng/L and 810-1,883 ng/L, respectively, were the predominant compounds among 19 PPs determined in the WW. The results indicate that aerobic digestion in biological ponds was insufficiently effective to degrade most of the PPs (reduction efficiency <0-50.0%) with the exception of four PPs that showed degradation efficiency varying from 55.0 to 99.9%. Tests of short-term chemical and enzymatic hydrolysis for PP degradation in WW samples were performed, and the results reflected the complexity of different degradation mechanisms and physicochemical transformations of PPs. The toxicological studies of WW impact on Daphnia magna indicated gradual reduction of the total toxicity through the treatment stages at the WWTP.

Development of a robotic patient positioning system with a wide beam-angle range for fixed-beam particle therapy

NASA Astrophysics Data System (ADS)

Choi, Hongseok; Park, Jong-Oh; Ko, Seong Young; Park, Sukho; Cho, Sungho; Jung, Won-Gyun; Park, Yong Kyun; Kang, Jung Suk

2016-10-01

This paper describes a robotic patient positioning system (PPS) for a fixed-beam heavy-ion therapy system. In order to extend the limited irradiation angle range of the fixed beam, we developed a 6-degree-of-freedom (6-DOF) serial-link robotic arm and used it as the robotic PPS for the fixed-beam heavy-ion therapy system. This research aims to develop a robotic PPS for use in the Korea Heavy Ion Medical Accelerator (KHIMA) system, which is under development at the Korea Institute of Radiological & Medical Sciences (KIRAMS). In particular, we select constraints and criteria that will be used for designing and evaluating the robotic PPS through full consultation with KIRAMS. In accordance with the constraints and criteria, we develop a 6-DOF serial-link robotic arm that consists of six revolute joints for the robotic PPS, where the robotic arm covers the upper body of a patient as a treatment area and achieves a 15 ° roll and pitch angle in the treatment area without any collision. Various preliminary experiments confirm that the robotic PPS can meet all criteria for extension of the limited irradiation angle range in the treatment area and has a positioning repeatability of 0.275 mm.

Polynomial Phase Estimation Based on Adaptive Short-Time Fourier Transform

PubMed Central

Jing, Fulong; Zhang, Chunjie; Si, Weijian; Wang, Yu; Jiao, Shuhong

2018-01-01

Polynomial phase signals (PPSs) have numerous applications in many fields including radar, sonar, geophysics, and radio communication systems. Therefore, estimation of PPS coefficients is very important. In this paper, a novel approach for PPS parameters estimation based on adaptive short-time Fourier transform (ASTFT), called the PPS-ASTFT estimator, is proposed. Using the PPS-ASTFT estimator, both one-dimensional and multi-dimensional searches and error propagation problems, which widely exist in PPSs field, are avoided. In the proposed algorithm, the instantaneous frequency (IF) is estimated by S-transform (ST), which can preserve information on signal phase and provide a variable resolution similar to the wavelet transform (WT). The width of the ASTFT analysis window is equal to the local stationary length, which is measured by the instantaneous frequency gradient (IFG). The IFG is calculated by the principal component analysis (PCA), which is robust to the noise. Moreover, to improve estimation accuracy, a refinement strategy is presented to estimate signal parameters. Since the PPS-ASTFT avoids parameter search, the proposed algorithm can be computed in a reasonable amount of time. The estimation performance, computational cost, and implementation of the PPS-ASTFT are also analyzed. The conducted numerical simulations support our theoretical results and demonstrate an excellent statistical performance of the proposed algorithm. PMID:29438317

Permeable pavement and stormwater management systems: a review.

PubMed

Imran, H M; Akib, Shatirah; Karim, Mohamed Rehan

2013-01-01

Uncontrolled stormwater runoff not only creates drainage problems and flash floods but also presents a considerable threat to water quality and the environment. These problems can, to a large extent, be reduced by a type of stormwater management approach employing permeable pavement systems (PPS) in urban, industrial and commercial areas, where frequent problems are caused by intense undrained stormwater. PPS could be an efficient solution for sustainable drainage systems, and control water security as well as renewable energy in certain cases. Considerable research has been conducted on the function of PPS and their improvement to ensure sustainable drainage systems and water quality. This paper presents a review of the use of permeable pavement for different purposes. The paper focuses on drainage systems and stormwater runoff quality from roads, driveways, rooftops and parking lots. PPS are very effective for stormwater management and water reuse. Moreover, geotextiles provide additional facilities to reduce the pollutants from infiltrate runoff into the ground, creating a suitable environment for the biodegradation process. Furthermore, recently, ground source heat pumps and PPS have been found to be an excellent combination for sustainable renewable energy. In addition, this study has identified several gaps in the present state of knowledge on PPS and indicates some research needs for future consideration.

Polynomial Phase Estimation Based on Adaptive Short-Time Fourier Transform.

PubMed

Jing, Fulong; Zhang, Chunjie; Si, Weijian; Wang, Yu; Jiao, Shuhong

2018-02-13

Polynomial phase signals (PPSs) have numerous applications in many fields including radar, sonar, geophysics, and radio communication systems. Therefore, estimation of PPS coefficients is very important. In this paper, a novel approach for PPS parameters estimation based on adaptive short-time Fourier transform (ASTFT), called the PPS-ASTFT estimator, is proposed. Using the PPS-ASTFT estimator, both one-dimensional and multi-dimensional searches and error propagation problems, which widely exist in PPSs field, are avoided. In the proposed algorithm, the instantaneous frequency (IF) is estimated by S-transform (ST), which can preserve information on signal phase and provide a variable resolution similar to the wavelet transform (WT). The width of the ASTFT analysis window is equal to the local stationary length, which is measured by the instantaneous frequency gradient (IFG). The IFG is calculated by the principal component analysis (PCA), which is robust to the noise. Moreover, to improve estimation accuracy, a refinement strategy is presented to estimate signal parameters. Since the PPS-ASTFT avoids parameter search, the proposed algorithm can be computed in a reasonable amount of time. The estimation performance, computational cost, and implementation of the PPS-ASTFT are also analyzed. The conducted numerical simulations support our theoretical results and demonstrate an excellent statistical performance of the proposed algorithm.

Effects of carboxymethyl cellulose incorporated with garlic essential oil composite coatings for improving quality of strawberries.

PubMed

Dong, Feng; Wang, Xiaolin

2017-11-01

The present study was aimed to determine the effects of carboxymethyl cellulose (CMC)/garlic essential oil (GEO) composite coatings in improving the quality of strawberries stored at 20°C and 35-40% RH. To find the effects of CMC/GEO composite coatings, strawberries were coated with CMC, CMC+GEO (1%), CMC+GEO (2%), CMC+GEO (3%) and stored, while the uncoated strawberries were taken as control during storing. The effectiveness of CMC/GEO composite coatings was evaluated by measuring their weight loss, decay percentage, ascorbic acid, total phenols, anthocyanins, titratable acidity, total soluble solids and sensory evaluation. After 6days of storage, CMC+GEO (2%) composite coatings was found very effective in decreasing the senescence and maintaining the nutritional contents of strawberries. Results of this study confirm that CMC/GEO composite coatings can be used to improve the quality of strawberries. Copyright © 2017. Published by Elsevier B.V.

a Study of Composite Coatings on 22MnCrNiMo Steel for Mooring Chain

NASA Astrophysics Data System (ADS)

Shen, Yan; Sahoo, Prasanta K.; Pan, Yipeng

In order to enhance the corrosion resistance of mooring chain, the composite coatings are carried out on the surface of 22MnCrNiMo steel for mooring chain by double-pulsed electrodeposition technology using centrifugal force in the rotating device. The microstructure and anti-corrosion performance of the composite coatings have been investigated experimentally. This paper mainly focuses on the experimental work to determine the structural characteristics and corrosion resistance of composite coatings in the presence of nano-SiC. The results show that the presence of nano-SiC has a significant effect on the preparation of composite coating during the process. The surface of the coating becomes compact and smooth at a moderate concentration of nano-SiC particles. Furthermore, the best corrosion resistance of the composite coatings can be obtained when the concentration of nano-SiC particles is 2.0g.L-1 after salt spray treatment.

Laser cladding of Inconel 625-based composite coatings reinforced by porous chromium carbide particles

NASA Astrophysics Data System (ADS)

Janicki, Damian

2017-09-01

Inconel 625/Cr3C2 composite coatings were produced via a laser cladding process using Cr3C2 reinforcing particles presenting an open porosity of about 60%. A laser cladding system used consisted of a direct diode laser with a rectangular beam spot and the top-hat beam profile, and an off-axis powder injection nozzle. The microstructural characteristics of the coatings was investigated with the use of scanning electron microscopy and X-ray diffraction. A complete infiltration of the porous structure of Cr3C2 reinforcing particles and low degree of their dissolution have been achieved in a very narrow range of processing parameters. Crack-free composite coatings having a uniform distribution of the Cr3C2 particles and their fraction up to 36 vol% were produced. Comparative erosion tests between the Inconel 625/Cr3C2 composite coatings and the metallic Inconel 625 coatings were performed following the ASTM G 76 standard test method. It was found that the composite coatings have a significantly higher erosion resistance to that of metallic coatings for both 30° and 90° impingement angles. Additionally, the erosion performances of composite coatings were similar for both the normal and oblique impact conditions. The erosive wear behaviour of composite coatings is discussed and related to the unique microstructure of these coatings.

Transoral robotic approach to parapharyngeal space tumors: Case series and technical limitations.

PubMed

Boyce, Brian J; Curry, Joseph M; Luginbuhl, Adam; Cognetti, David M

2016-08-01

The transoral robotic approach to parapharyngeal space (PPS) tumors is a new technique with limited data available on its feasibility, safety, and efficacy. We analyzed our experience with transoral robotic excisions of PPS tumors to evaluate the safety and efficacy of this technique. Retrospective chart analysis at tertiary academic medical center. From July 2010 to June 2014, 17 patients who had transoral robotic excision of PPS tumors were included in the study. Our cohort had an average age of 61.6 years and was 52.9% male. All patients had successful removal of their PPS tumors, and the average size of the tumors was 27.3 cm(3) (range 2-80 cm(3) ). Two cases (11.7%) required a cervical incision to assist with tumor removal. The average total operative time was 140.5 minutes. Two PPS PAs had focal areas of capsule rupture and one was fragmented. The average length of stay was 1.8 days (range 1-7 days), and all patients were discharged on an oral diet. Three patients experienced complications. There was no clinical or radiographic evidence of recurrence. This is the largest single-institution case series of transoral robotic approaches to PPS tumors. We demonstrate that this approach is feasible and safe but also note limitations of the robotic approaches for tumors on the far lateral and superior areas of the PPS, which required transcervical assistance. There were no patients who demonstrated recurrent tumor either radiographically or clinically. 4. Laryngoscope, 126:1776-1782, 2016. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Co-expression of five genes in E coli for L-phenylalanine in Brevibacterium flavum

PubMed Central

Wu, Yong-Qing; Jiang, Pei-Hong; Fan, Chang-Sheng; Wang, Jian-Gang; Shang, Liang; Huang, Wei-Da

2003-01-01

AIM: To study the effect of co-expression of ppsA, pckA, aroG, pheA and tyrB genes on the production of L-phenylalanine, and to construct a genetic engineering strain for L-phenylalanine. METHODS: ppsA and pckA genes were amplified from genomic DNA of E. coli by polymerase chain reaction, and then introduced into shuttle vectors between E coli and Brevibacterium flavum to generate constructs pJN2 and pJN5. pJN2 was generated by inserting ppsA and pckA genes into vector pCZ; whereas pJN5 was obtained by introducing ppsA and pckA genes into pCZ-GAB, which was originally constructed for co-expression of aroG, pheA and tyrB genes. The recombinant plasmids were then introduced into B. flavum by electroporation and the transformants were used for L-phenylalanine fermentation. RESULTS: Compared with the original B. flavum cells, all the transformants were showed to have increased five enzyme activities specifically, and have enhanced L-phenylalanine biosynthesis ability variably. pJN5 transformant was observed to have the highest elevation of L-phenylalanine production by a 3.4-fold. Co-expression of ppsA and pckA increased activity of DAHP synthetase significantly. CONCLUSION: Co-expression of ppsA and pckA genes in B. flavum could remarkably increase the expression of DAHP synthetase; Co-expression of ppsA, pckA, aroG, pheA and tyrB of E. coli in B. flavum was a feasible approach to construct a strain for phenylalanine production. PMID:12532463

ZnO nanorod array polydimethylsiloxane composite solid phase micro-extraction fiber coating: fabrication and extraction capability.

PubMed

Wang, Dan; Wang, Qingtang; Zhang, Zhuomin; Chen, Guonan

2012-01-21

ZnO nanorod array coating is a novel kind of solid-phase microextraction (SPME) fiber coating which shows good extraction capability due to the nanostructure. To prepare the composite coating is a good way to improve the extraction capability. In this paper, the ZnO nanorod array polydimethylsiloxane (PDMS) composite SPME fiber coating has been prepared and its extraction capability for volatile organic compounds (VOCs) has been studied by headspace sampling the typical volatile mixed standard solution of benzene, toluene, ethylbenzene and xylene (BTEX). Improved detection limit and good linear ranges have been achieved for this composite SPME fiber coating. Also, it is found that the composite SPME fiber coating shows good extraction selectivity to the VOCs with alkane radicals.

Long-term modelling of fly ash and radionuclide emissions as well as deposition fluxes due to the operation of large oil shale-fired power plants.

PubMed

Vaasma, Taavi; Kaasik, Marko; Loosaar, Jüri; Kiisk, Madis; Tkaczyk, Alan H

2017-11-01

Two of the world's largest oil shale-fired power plants (PPs) in Estonia have been operational over 40 years, emitting various pollutants, such as fly ash, SO x , NO x , heavy metals, volatile organic compounds as well as radionuclides to the environment. The emissions from these PPs have varied significantly during this period, with the maximum during the 1970s and 1980s. The oil shale burned in the PPs contains naturally occurring radionuclides from the 238 U and 232 Th decay series as well as 40 K. These radionuclides become enriched in fly ash fractions (up to 10 times), especially in the fine fly ash escaping the purification system. Using a validated Gaussian-plume model, atmospheric dispersion modelling was carried out to determine the quantity and a real magnitude of fly ash and radionuclide deposition fluxes during different decades. The maximum deposition fluxes of volatile radionuclides ( 210 Pb and 210 Po) were around 70 mBq m -2 d -1 nearby the PPs during 1970s and 1980s. Due to the reduction of burned oil shale and significant renovations done on the PPs, the deposition fluxes were reduced to 10 mBq m -2 d -1 in the 2000s and down to 1.5 mBq m -2 d -1 in 2015. The maximum deposition occurs within couple of kilometers of the PPs, but the impacted area extends to over 50 km from the sources. For many radionuclides, including 210 Po, the PPs have been larger contributors of radionuclides to the environment via atmospheric pathway than natural sources. This is the first time that the emissions and deposition fluxes of radionuclides from the PPs have been quantified, providing the information about their radionuclide deposition load on the surrounding environment during various time periods. Copyright © 2017 Elsevier Ltd. All rights reserved.

Post-Polio Syndrome and Risk Factors in Korean Polio Survivors: A Baseline Survey by Telephone Interview

PubMed Central

Bang, Hyun; Suh, Jee Hyun; Lee, Seung Yeol; Kim, Keewon; Yang, Eun Joo; Jung, Se Hee; Jang, Soong-Nang; Han, Soo Jeong; Kim, Wan-Ho; Oh, Min-Gyun; Kim, Jeong-Hwan; Lee, Sam-Gyu

2014-01-01

Objective To obtain information on the socioeconomic, medical, and functional status of polio survivors, and to use these results as the preliminary data for establishing the middle-aged cohort of polio survivors. Methods The subjects were recruited based on the medical records of multiple hospitals and centers. They were assessed through a structured questionnaire over the phone. Post-poliomyelitis syndrome (PPS) was identified according to the specified diagnostic criteria. Differences between polio survivors with or without PPS were evaluated, and the risk factors for PPS were analyzed by the odds ratio (OR). Results Majority of polio survivors were middle-aged and mean age was 51.2±8.3 years. A total of 188 out of 313 polio survivors met the adopted criteria for PPS based on the symptoms, yielding a prevalence of 61.6%. Mean interval between acute poliomyelitis and the development of PPS was 38.5±11.6 years. Female gender (OR 1.82; confidence interval [CI] 1.09-3.06), the age at onset of poliomyelitis (OR 1.75; CI 1.05-2.94), the use of orthoses or walking aids (OR 2.46; CI 1.44-4.20), and the history of medical treatment for paralysis, pain or gait disturbance (OR 2.62; CI 1.52-4.51) represented independent risk factors for PPS. Conclusion We found that the majority of Korean polio survivors entered middle age with many medical, functional, and social problems. Female gender, early age of onset of poliomyelitis, the use of orthoses or walking aids, and the history of medical treatment for paralysis, pain or gait disturbance were identified as the significant risk factors for PPS. A comprehensive and multidisciplinary plan should be prepared to manage polio survivors considering their need for health care services and the risk factors for late effects, such as PPS. PMID:25379493

Activity of plasma sprayed yttria stabilized zirconia reinforced hydroxyapatite/Ti-6Al-4V composite coatings in simulated body fluid.

PubMed

Gu, Y W; Khor, K A; Pan, D; Cheang, P

2004-07-01

Hydroxyapatite (HA)/yttria stabilized zirconia/Ti-6Al-4V bio-composite coatings deposited onto Ti-6Al-4V substrate through a plasma spray technique were immersed in simulated body fluid (SBF) to investigate their behavior in vitro. Surface morphologies and structural changes in the coatings were analyzed by scanning electron microscopy, thin-film X-ray diffractometer, and X-ray photoelectron spectroscopy. The tensile bond strength of the coatings after immersion was also conducted through the ASTM C-633 standard for thermal sprayed coatings. Results showed that carbonate-containing hydroxyapatite (CHA) layer formed on the surface of composite coatings after 4 weeks immersion in SBF solution, indicating the composite coating possessed excellent bioactivity. The mechanical properties were found to decrease with immersion duration of maximum 56 days. However, minimal variation in mechanical properties was found subsequent to achieving supersaturation of the calcium ions, which was attained with the precipitation of the calcium phosphate layers. The mechanical properties of the composite coating were found to be significantly higher than those of pure HA coatings even after immersion in the SBF solution, indicating the enhanced mechanical properties of the composite coatings.

Response of Cr and Cr-Al coatings on Zircaloy-2 to high temperature steam

NASA Astrophysics Data System (ADS)

Zhong, Weicheng; Mouche, Peter A.; Heuser, Brent J.

2018-01-01

The oxidation behavior of chromium (Cr) and chromium-aluminum (CrAl) coatings with various compositions deposited on Zircaloy-2 to 700 °C high-temperature steam (HTS) exposure has been investigated. CrAl coatings with higher Al compositions demonstrate lower oxidation weight gain. A layer of γ-alumina developed on the CrAl coatings with Al composition over 43 at%, while Al2O3 and Cr2O3 developed on CrAl coatings with Al composition below 33 at%. Oxidation of Zircaloy-2 substrate was inhibited by the 1um coatings to 20 h HTS exposure. Coating constituent elements diffused into the substrate and formed intermetallic phases with the Zircaloy substrate. Thicker layers of intermetallic phases developed on the coatings with higher Al composition. The intermetallic phases included Fe and Ni, indicating the dissolution of second phase particles (SPPs) during HTS exposure.

Electrophoretic deposition of double-layer HA/Al composite coating on NiTi.

PubMed

Karimi, Esmaeil; Khalil-Allafi, Jafar; Khalili, Vida

2016-01-01

In order to improve the bioactivity of NiTi alloys, which are being known as the suitable materials for biomedical applications, numerous NiTi disks were electrophoretically coated by hetero-coagulated hydroxyapatite/aluminum composite coatings in three main voltages from suspensions with different Al concentrations. In this paper, the amount of Ni ions release and bioactivity of prepared samples as well as bonding strength of the coating to substrate were investigated. The surface characterization of the coating by XRD, EDX, SEM, and FTIR showed that HA particles bonded by Al particles. It caused the formation of a free crack coating on NiTi disks. Moreover, the bonding strength of HA/Al coatings to NiTi substrate were improved by two times as compared to that of the pure HA coatings. Immersing of coated samples in SBF for 1 week showed that apatite formation ability was improved on HA/Al composite coating and Ni ions release from the surface of composite coating decreased. These results induce the appropriate bioactivity and biocompatibility of the deposited HA/Al composite coatings on NiTi disks. Copyright © 2015 Elsevier B.V. All rights reserved.

Incorporation of Copper Enhances the Anti-Ageing Property of Flame-Sprayed High-Density Polyethylene Coatings

NASA Astrophysics Data System (ADS)

Jia, Zhengmei; Huang, Jing; Gong, Yongfeng; Jin, Peipeng; Suo, Xinkun; Li, Hua

2017-02-01

High-density polyethylene (HDPE)-copper (Cu) composite coatings were prepared through depositing HDPE-Cu core-shell particles by flame spraying. The HDPE-Cu composite coatings and the HDPE coatings were aged in xenon lamp ageing testing chamber. The variations of chemical compositions and surface morphology of the coatings before and after the ageing testing were analyzed using infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry and ultraviolet-visible spectrophotometer. Results show that there is no chemical composition variation in the HDPE-Cu coatings. Cracks were found on the surfaces of the HDPE coatings, while the HDPE-Cu coating shows almost intact surface morphology. These results suggest that the HDPE-Cu coatings present better anti-ageing performances than the HDPE coatings. Further assessment of the function of Cu shells on the anti-ageing property reveals that Cu shells not only enhanced the absorption of the coatings to ultraviolet, but also increased their reflectivity to visible light. Additionally, the Cu shells enhanced the decomposition temperature and thermal stability of HDPE in the composite coatings. These results give bright insight into potential anti-ageing applications of the polymer-based structures.

Characterization of in situ synthesized TiB 2 reinforcements in iron-based composite coating

NASA Astrophysics Data System (ADS)

Zhang, Panpan; Wang, Xibao; Guo, Lijie; Cai, Lijuan; Sun, Hongling

2011-12-01

TiB2 reinforced iron-based composite coatings can be fabricated on the mild steel substrate with a powder mixture of Ti and B4C by plasma transferred arc (PTA) powder surfacing process. Characterizations of the TiB2 reinforcements in the coated surface were investigated in this paper. The experimental work enables the following findings to be obtained: (i) acicular shaped and blocky formed TiB2 phases could be synthesized in situ using PTA powder surfacing process in the iron-based composite coating. (ii) Gradient distributions of TiB2 reinforcements appeared in the composite coating from both the vertical and horizontal direction of the coating's cross-section. Significant changes of the size, shape and volume fraction for TiB2 particles appeared in different regions of the surface coating, due to the effects of the dilution rate and mass density. (iii) Values of coating dilution could have profound impacts on the characterization of TiB2 reinforcements in the coated surfaces. With the increase of coating dilution, TiB2 grain tends to be acicular shaped at the edge of the surface coating, while it remains to be granular formed in the center of the composite coating.

Surfactant-free electrodeposition of reduced graphene oxide/copper composite coatings with enhanced wear resistance

NASA Astrophysics Data System (ADS)

Mai, Y. J.; Zhou, M. P.; Ling, H. J.; Chen, F. X.; Lian, W. Q.; Jie, X. H.

2018-03-01

How to uniformly disperse graphene sheets into the electrolyte is one of the main challenges to synthesize graphene enhanced nanocomposites by electrodeposition. A surfactant-free colloidal solution comprised of copper (II)-ethylene diamine tetra acetic acid ([CuIIEDTA]2-) complexes and graphene oxide (GO) sheets is proposed to electrodeposit reduced graphene oxide/copper (RGO/Cu) composite coatings. Anionic [CuIIEDTA]2- complexes stably coexist with negatively charged GO sheets due to the electrostatic repulsion between them, facilitating the electrochemical reduction and uniform dispersion of GO sheets into the copper matrix. The RGO/Cu composite coatings are well characterized by XRD, Raman, SEM and XPS. Their tribological behavior as a function of RGO content in composite coatings and normal loads are investigated. Also the chemical composition and topography of the wear tracks for the composite coatings are analyzed to deduce the lubricating and anti-wear mechanism of RGO/Cu composite coatings.

MSL Lessons Learned and Knowledge Capture

NASA Technical Reports Server (NTRS)

Buxbaum, Karen L.

2012-01-01

The Mars Program has recently been informed of the Planetary Protection Subcommittee (PPS) recommendation, which was endorsed by the NAC, concerning Mars Science Lab (MSL) lessons learned and knowledge capture. The Mars Program has not had an opportunity to consider any decisions specific to the PPS recommendation. Some of the activities recommended by the PPS would involve members of the MSL flight team who are focused on cruise, entry descent & landing, and early surface operations; those activities would have to wait. Members of the MSL planetary protection team at JPL are still available to support MSL lessons learned and knowledge capture; some of the specifically recommended activities have already begun. The Mars Program shares the PPS/NAC concerns about loss of potential information & expertise in planetary protection practice.

Effects of Interface Coating and Nitride Enhancing Additive on Properties of Hi-Nicalon SiC Fiber Reinforced Reaction-Bonded Silicon Nitride Composites

NASA Technical Reports Server (NTRS)

Bhatt, Ramakrishana T.; Hull, David R.; Eldridge, Jeffrey I.; Babuder, Raymond

2000-01-01

Strong and tough Hi-Nicalon SiC fiber reinforced reaction-bonded silicon nitride matrix composites (SiC/ RBSN) have been fabricated by the fiber lay-up approach. Commercially available uncoated and PBN, PBN/Si-rich PBN, and BN/SiC coated SiC Hi-Nicalon fiber tows were used as reinforcement. The composites contained approximately 24 vol % of aligned 14 micron diameter SiC fibers in a porous RBSN matrix. Both one- and two-dimensional composites were characterized. The effects of interface coating composition, and the nitridation enhancing additive, NiO, on the room temperature physical, tensile, and interfacial shear strength properties of SiC/RBSN matrix composites were evaluated. Results indicate that for all three coated fibers, the thickness of the coatings decreased from the outer periphery to the interior of the tows, and that from 10 to 30 percent of the fibers were not covered with the interface coating. In the uncoated regions, chemical reaction between the NiO additive and the SiC fiber occurs causing degradation of tensile properties of the composites. Among the three interface coating combinations investigated, the BN/SiC coated Hi-Nicalon SiC fiber reinforced RBSN matrix composite showed the least amount of uncoated regions and reasonably uniform interface coating thickness. The matrix cracking stress in SiC/RBSN composites was predicted using a fracture mechanics based crack bridging model.

Influence of Metal-Coated Graphite Powders on Microstructure and Properties of the Bronze-Matrix/Graphite Composites

NASA Astrophysics Data System (ADS)

Zhao, Jian-hua; Li, Pu; Tang, Qi; Zhang, Yan-qing; He, Jian-sheng; He, Ke

2017-02-01

In this study, the bronze-matrix/x-graphite (x = 0, 1, 3 and 5%) composites were fabricated by powder metallurgy route by using Cu-coated graphite, Ni-coated graphite and pure graphite, respectively. The microstructure, mechanical properties and corrosive behaviors of bronze/Cu-coated-graphite (BCG), bronze/Ni-coated-graphite (BNG) and bronze/pure-graphite (BPG) were characterized and investigated. Results show that the Cu-coated and Ni-coated graphite could definitely increase the bonding quality between the bronze matrix and graphite. In general, with the increase in graphite content in bronze-matrix/graphite composites, the friction coefficients, ultimate density and wear rates of BPG, BCG and BNG composites all went down. However, the Vickers microhardness of the BNG composite would increase as the graphite content increased, which was contrary to the BPG and BCG composites. When the graphite content was 3%, the friction coefficient of BNG composite was more stable than that of BCG and BPG composites, indicating that BNG composite had a better tribological performance than the others. Under all the values of applied loads (10, 20, 40 and 60N), the BCG and BNG composites exhibited a lower wear rate than BPG composite. What is more, the existence of nickel in graphite powders could effectively improve the corrosion resistance of the BNG composite.

Electrical contact arrangement for a coating process

DOEpatents

Kabagambe, Benjamin; McCamy, James W; Boyd, Donald W

2013-09-17

A protective coating is applied to the electrically conductive surface of a reflective coating of a solar mirror by biasing a conductive member having a layer of a malleable electrically conductive material, e.g. a paste, against a portion of the conductive surface while moving an electrodepositable coating composition over the conductive surface. The moving of the electrodepositable coating composition over the conductive surface includes moving the solar mirror through a flow curtain of the electrodepositable coating composition and submerging the solar mirror in a pool of the electrodepositable coating composition. The use of the layer of a malleable electrically conductive material between the conductive member and the conductive surface compensates for irregularities in the conductive surface being contacted during the coating process thereby reducing the current density at the electrical contact area.

Wear Resistance Properties Reinforcement Using Nano-Al/Cu Composite Coating in Sliding Bearing Maintenance.

PubMed

Liu, Hongtao; Li, Zhixiong; Wang, Jianmei; Sheng, Chenxing; Liu, Wanli

2018-03-01

Sliding bearing maintenance is crucial for reducing the cost and extending the service life. An efficient and practical solution is to coat a restorative agent onto the worn/damaged bearings. Traditional pure-copper (Cu) coating results in a soft surface and poor abrasion resistance. To address this issue, this paper presents a nano-composite repairing coating method. A series of nano-Al/Cu coatings were prepared on the surface of 45 steel by composite electro-brush plating (EBP). Their micro-hardness was examined by a MHV-2000 Vickers hardness tester, and tribological properties by a UMT-2M Micro-friction tester, 3D profiler and SEM. Then, the influence of processing parameters such as nano-particle concentration and coating thickness on the micro-hardness of nano-Al/Cu coating was analyzed. The experimental analysis results demonstrate that, when the nano-Al particle concentration in electrolyte was 10 g/L, the micro-hardness of the composite coating was 1.1 times as much as that of pure-Cu coating. When the Al nano-particle concentration in electrolyte was 20 g/L, the micro-hardness of the composite coating reached its maximum value (i.e., 231.6 HV). Compared with the pure-Cu coating, the hardness and wear resistance of the nano-composite coating were increased, and the friction coefficient and wear volume were decreased, because of the grain strengthening and dispersion strengthening. The development in this work may provide a feasible and effective nano-composite EBP method for sliding bearing repair.

Extraordinarily soft, medium-hard and hard Indian wheat varieties: Composition, protein profile, dough and baking properties.

PubMed

Katyal, Mehak; Singh, Narpinder; Virdi, Amardeep Singh; Kaur, Amritpal; Chopra, Nidhi; Ahlawat, Arvind Kumar; Singh, Anju Mahendru

2017-10-01

Hard wheat (HW), medium-hard wheat (MHW) and extraordinarily soft wheat (Ex-SW) varieties with grain hardness index (GHI) of 83 to 95, 72 to 80, 17 to 29 were evaluated for pasting, protein molecular weight (MW) distribution, dough rheology and baking properties. Flours from varieties with higher GHI had more protein content, ash content and paste viscosities. Ex-SW had more glutenins proportion as compared to HW and MHW. Flours from Ex-SW varieties showed lower NaSRC, WA and mixographic parameters as compared to HW and MHW. Dough from flours milled from Ex-SW had higher Intermolecular-β-sheets (IM-β-sheets) than those from MHW and HW. Muffins volume increased with decrease in GHI, Ex-SW varieties had more muffin volume and less air space. The accumulation of polypeptides (PPs) varied significantly in different varieties. Ex-SW variety (QBP12-10) showed accumulation of 98, 90, 81 and 79kDa PPs, which was unique and was different from other varieties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Osteoinductive composite coatings for flexible intramedullary nails.

PubMed

Bolbasov, E N; Popkov, A V; Popkov, D A; Gorbach, E N; Khlusov, I A; Golovkin, A S; Sinev, A; Bouznik, V M; Tverdokhlebov, S I; Anissimov, Y G

2017-06-01

This work presents composite coatings based on a copolymer of vinylidene fluoride with tetrafluoroethylene (VDF-TeFE) and hydroxyapatite (HA) for flexible intramedullary nails (FIN). The effect of the proportion of VDF-TeFE (100-25% wt.) on physicochemical and biological properties of the composite coatings was investigated. It was shown that a decrease of VDF-TeFE in the coating hinders its crystallization in β and γ forms which have piezoelectric properties. The decrease also reduces an adhesive strength to 9.9±2.4MPa and a relative elongation to 5.9±1.2%, but results in increased osteogenesis. It was demonstrated that the composite coatings with 35% VDF-TeFE has the required combination of physicochemical properties and osteogenic activity. Comparative studies of composite coatings (35% VDF-TeFE) and calcium phosphate coatings produced using micro-arc oxidation, demonstrated comparable results for strength of bonding of these FINs with trabecular bones (~530MPa). It was hypothesized that the high osteoinductive properties of the composite coatings are due to their piezoelectric properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Anatomic Severity, Midfacial Growth, and Speech Outcomes in Van der Woude/Popliteal Pterygium Syndromes Compared to Nonsyndromic Cleft Lip/Palate.

PubMed

Reardon, Jeffrey B; Brustowicz, Katherine A; Marrinan, Eileen M; Mulliken, John B; Padwa, Bonnie L

2015-11-01

To summarize the clinical characteristics and surgical and speech outcomes for patients with Van der Woude/popliteal pterygium syndromes (VWS/PPS) and to compare them with a historic cohort of patients with nonsyndromic cleft lip/cleft palate (CL/P). Retrospective chart review. Tertiary care center. All patients with VWS/PPS seen at Boston Children's Hospital from 1979 to 2012: 28 patients with VWS (n = 21)/PPS (n = 7) whose mean age was 17.3 ± 10.4 years, including 18 females (64%) and 10 males (36%); 18 patients (64%) had a family history of VWS/PPS. Cleft type, operative procedures, speech, and midfacial growth. Data were compared with historic cohorts of patients with nonsyndromic CL/P treated at one tertiary care center. There were 24 patients (86%) with CP±L, Veau types I (n = 4, 17%), II (n = 4, 17%), III (n = 5, 21%), and IV (n = 11, 46%). Nine patients (38%) had palatal fistula after palatoplasty. Fourteen of 23 (61%) patients with CL/P age 5 years or older had midfacial retrusion, and 10 (43%) required a pharyngeal flap for velopharyngeal insufficiency. Fisher's exact test demonstrated higher frequencies of Veau type IV CP±L (P = .0016), bilateral CL±P (P = .0001), and complete CL±P (P < .0001) in VWS/PPS compared with nonsyndromic patients. Incidences of midfacial retrusion (P = .0001), palatal fistula (P < .0001), and need for pharyngeal flap (P = .0014) were significantly greater in patients with VWS/PPS. Patients with VWS/PPS have more severe forms of labiopalatal clefting and higher incidences of midfacial retrusion, palatal fistula, and velopharyngeal insufficiency following primary repair as compared with nonsyndromic CL/P.

Helping members of a community-based health insurance scheme access quality inpatient care through development of a preferred provider system in rural Gujarat.

PubMed

Ranson, M Kent; Sinha, Tara; Gandhi, Fenil; Jayswal, Rupal; Mills, Anne J

2006-01-01

We describe and analyse the experience of piloting a preferred provider system (PPS) for rural members of Vimo SEWA, a fixed-indemnity, community-based health insurance (CBHI) scheme run by the Self-Employed Women's Association (SEWA). The objectives of the PPS were (i) to facilitate access to hospitalization by providing financial benefits at the time of service utilization; (ii) to shift the burden of compiling a claim away from members and towards Vimo SEWA staff; and (iii) to direct members to inpatient facilities of acceptable quality. The PPS was launched between August and October 2004, in 8 subdistricts covering 15,000 insured. The impact of the scheme was analysed using data from a household survey of claimants and qualitative data from in-depth interviews and focus group discussions. The PPS appears to have been successful in terms of two of the three primary objectives--it has transferred much of the burden of compiling a health Insurance claim onto Vimo SEWA staff, and it has directed members to inpatient facilities with acceptable levels of technical quality (defined in terms of structural Indicators). However, even under the PPS, user fees pose a financial barrier, as the insured have to mobilize funds to cover the costs of medicines, supplies, registration fee, etc. before receipt of cash payment from Vimo SEWA. Other barriers to the success of the PPS were the geographic Inaccessibility of some of the selected hospitals, lack of awareness about the PPS among members and a variety of administrative problems. This pilot project provides useful lessons relating to strategic purchasing by CBHI schemes and, more broadly, managed care in India. In particular, the pragmatic approach taken to assessing hospitals and identifying preferred providers is likely to be useful elsewhere.

Full body action remapping of peripersonal space: the case of walking.

PubMed

Noel, Jean-Paul; Grivaz, Petr; Marmaroli, Patrick; Lissek, Herve; Blanke, Olaf; Serino, Andrea

2015-04-01

The space immediately surrounding the body, i.e. peripersonal space (PPS), is represented by populations of multisensory neurons, from a network of premotor and parietal areas, which integrate tactile stimuli from the body's surface with visual or auditory stimuli presented within a limited distance from the body. Here we show that PPS boundaries extend while walking. We used an audio-tactile interaction task to identify the location in space where looming sounds affect reaction time to tactile stimuli on the chest, taken as a proxy of the PPS boundary. The task was administered while participants either stood still or walked on a treadmill. In addition, in two separate experiments, subjects either received or not additional visual inputs, i.e. optic flow, implying a translation congruent with the direction of their walking. Results revealed that when participants were standing still, sounds boosted tactile processing when located within 65-100 cm from the participants' body, but not at farther distances. Instead, when participants were walking PPS expands as reflected in boosted tactile processing at ~1.66 m. This was found despite the fact the spatial relationship between the participant's body and the sound's source did not vary between the Standing and the Walking condition. This expansion effect on PPS boundaries due to walking was the same with or without optic flow, suggesting that kinematics and proprioceptive cues, rather than visual cues, are critical in triggering the effect. These results are the first to demonstrate an adaptation of the chest's PPS representation due to whole body motion and are compatible with the view that PPS constitutes a dynamic sensory-motor interface between the individual and the environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

The wheelchair as a full-body tool extending the peripersonal space

PubMed Central

Galli, Giulia; Noel, Jean Paul; Canzoneri, Elisa; Blanke, Olaf; Serino, Andrea

2015-01-01

Dedicated multisensory mechanisms in the brain represent peripersonal space (PPS), a limited portion of space immediately surrounding the body. Previous studies have illustrated the malleability of PPS representation through hand-object interaction, showing that tool use extends the limits of the hand-centered PPS. In the present study we investigated the effects of a special tool, the wheelchair, in extending the action possibilities of the whole body. We used a behavioral measure to quantify the extension of the PPS around the body before and after Active (Experiment 1) and Passive (Experiment 2) training with a wheelchair and when participants were blindfolded (Experiment 3). Results suggest that a wheelchair-mediated passive exploration of far space extended PPS representation. This effect was specifically related to the possibility of receiving information from the environment through vision, since no extension effect was found when participants were blindfolded. Surprisingly, the active motor training did not induce any modification in PPS representation, probably because the wheelchair maneuver was demanding for non-expert users and thus they may have prioritized processing of information from close to the wheelchair rather than at far spatial locations. Our results suggest that plasticity in PPS representation after tool use seems not to strictly depend on active use of the tool itself, but is triggered by simultaneous processing of information from the body and the space where the body acts in the environment, which is more extended in the case of wheelchair use. These results contribute to our understanding of the mechanisms underlying body–environment interaction for developing and improving applications of assistive technological devices in different clinical populations. PMID:26042069

Fengycin produced by Bacillus subtilis 9407 plays a major role in the biocontrol of apple ring rot disease.

PubMed

Fan, Haiyan; Ru, Jinjiang; Zhang, Yuanyuan; Wang, Qi; Li, Yan

2017-06-01

Apple ring rot, caused by Botryosphaeria dothidea, is a serious apple disease in China. Bacillus subtilis 9407 was isolated from healthy apples and showed strong antifungal activity against B. dothidea. To identify the primary antifungal compound of B. subtilis 9407 and determine its role in controlling apple ring rot, a transposon mutant library was constructed using TnYLB-1, and a mutant completely defective in antifungal activity was obtained. The gene inactivated in the antifungal activity mutant had 98.5% similarity to ppsB in B. subtilis subsp. subtilis str. 168, which encodes one of the five synthetases responsible for synthesizing fengycin. A markerless ppsB deletion mutant was constructed. Compared with the wild-type strain, lipopeptide crude extracts from ΔppsB showed almost no inhibition of B. dothidea mycelial growth. Furthermore, fengycin-like lipopeptides (retention factor 0.1-0.2) that exhibited antifungal activity against B. dothidea were observed in the wild-type strain by thin-layer chromatography (TLC)-bioautography analysis, but not in ΔppsB. Semipreparative reverse-phase high performance liquid chromatography (RP-HPLC) detection revealed that ΔppsB lost the ability to synthesize fengycin. These results suggest that ppsB is responsible for synthesizing fengycin and that fengycin is the major antifungal compound produced by B. subtilis 9407 against B. dothidea. Moreover, a biocontrol assay showed that the control efficacy of ΔppsB was reduced by half compared with the wild-type strain, indicating that fengycin plays a major role in controlling apple ring rot disease. This is the first report on the use of a B. subtilis strain as a potential biological control agent to control apple ring rot disease by the production of fengycin. Copyright © 2017 Elsevier GmbH. All rights reserved.

Simple prognostic model for patients with advanced cancer based on performance status.

PubMed

Jang, Raymond W; Caraiscos, Valerie B; Swami, Nadia; Banerjee, Subrata; Mak, Ernie; Kaya, Ebru; Rodin, Gary; Bryson, John; Ridley, Julia Z; Le, Lisa W; Zimmermann, Camilla

2014-09-01

Providing survival estimates is important for decision making in oncology care. The purpose of this study was to provide survival estimates for outpatients with advanced cancer, using the Eastern Cooperative Oncology Group (ECOG), Palliative Performance Scale (PPS), and Karnofsky Performance Status (KPS) scales, and to compare their ability to predict survival. ECOG, PPS, and KPS were completed by physicians for each new patient attending the Princess Margaret Cancer Centre outpatient Oncology Palliative Care Clinic (OPCC) from April 2007 to February 2010. Survival analysis was performed using the Kaplan-Meier method. The log-rank test for trend was employed to test for differences in survival curves for each level of performance status (PS), and the concordance index (C-statistic) was used to test the predictive discriminatory ability of each PS measure. Measures were completed for 1,655 patients. PS delineated survival well for all three scales according to the log-rank test for trend (P < .001). Survival was approximately halved for each worsening performance level. Median survival times, in days, for each ECOG level were: EGOG 0, 293; ECOG 1, 197; ECOG 2, 104; ECOG 3, 55; and ECOG 4, 25.5. Median survival times, in days, for PPS (and KPS) were: PPS/KPS 80-100, 221 (215); PPS/KPS 60 to 70, 115 (119); PPS/KPS 40 to 50, 51 (49); PPS/KPS 10 to 30, 22 (29). The C-statistic was similar for all three scales and ranged from 0.63 to 0.64. We present a simple tool that uses PS alone to prognosticate in advanced cancer, and has similar discriminatory ability to more complex models. Copyright © 2014 by American Society of Clinical Oncology.

Peripersonal space as the space of the bodily self.

PubMed

Noel, Jean-Paul; Pfeiffer, Christian; Blanke, Olaf; Serino, Andrea

2015-11-01

Bodily self-consciousness (BSC) refers to experience of one's self as located within an owned body (self-identification) and as occupying a specific location in space (self-location). BSC can be altered through multisensory stimulation, as in the Full Body Illusion (FBI). If participants view a virtual body from a distance being stroked, while receiving synchronous tactile stroking on their physical body, they feel as if the virtual body were their own and they experience, subjectively, to drift toward the virtual body. Here we hypothesized that--while normally the experience of the body in space depends on the integration of multisensory body-related signals within a limited space surrounding the body (i.e. peripersonal space, PPS)--during the FBI the boundaries of PPS would shift toward the virtual body, that is, toward the position of experienced self-location. To test this hypothesis, we used synchronous visuo-tactile stroking to induce the FBI, as contrasted with a control condition of asynchronous stroking. Concurrently, we applied an audio-tactile interaction paradigm to estimate the boundaries of PPS. PPS was measured in front of and behind the participants' body as the distance where tactile information interacted with auditory stimuli looming in space toward the participant's physical body. We found that during synchronous stroking, i.e. when participants experienced the FBI, PPS boundaries extended in the front-space, toward the avatar, and concurrently shrunk in the back-space, as compared to the asynchronous stroking control condition, when FBI was induced. These findings support the view that during the FBI, PPS boundaries translate toward the virtual body, such that the PPS representation shifts from being centered at the location of the physical body to being now centered at the subjectively experienced location of the self. Copyright © 2015 Elsevier B.V. All rights reserved.

Peripersonal Space as the space of the Bodily Self

PubMed Central

Noel, Jean-Paul; Pfeiffer, Christian; Blanke, Olaf; Serino, Andrea

2016-01-01

Bodily self-consciousness (BSC) refers to experience of our self as located within an owned body (self-identification) and as occupying a specific location in space (self-location). BSC can be altered through multisensory stimulation, as in the Full Body Illusion (FBI). If participants view a virtual body from a distance being stroked, while receiving synchronous tactile stroking on their physical body, they feel such as the virtual body were their own and they experience, subjectively, to drift toward the virtual body. Here we hypothesized that - while normally the experience of the body in space depends on the integration of multisensory body-related signals within a limited space surrounding the body (i.e. peripersonal space, PPS) - during the FBI the boundaries of PPS would shift toward the virtual body, that is toward the position of self-location. To test this hypothesis, we used synchronous visuo-tactile stroking to induce the FBI, as contrasted with a control condition of asynchronous stroking. Concurrently, we applied an audio-tactile interaction paradigm to estimate the boundaries of PPS. PPS was measured in front of and behind the participants' body as the distance where tactile information interacted with auditory stimuli looming in space toward the participant's physical body. We found that during synchronous stroking, i.e. when participants experienced the FBI, PPS boundaries extended in the front-space, toward the avatar, and concurrently shrunk in the back-space, as compared to the asynchronous stroking control condition, where no FBI was induced. These findings support the view that during the FBI, PPS boundaries translate toward the virtual body, such that the PPS representation shifts from being centered at the location of the physical body to being now centered at the subjectively experienced location of the self. PMID:26231086

Capacity upgrade in short-reach optical fibre networks: simultaneous 4-PAM 20 Gbps data and polarization-modulated PPS clock signal using a single VCSEL carrier

NASA Astrophysics Data System (ADS)

Isoe, G. M.; Wassin, S.; Gamatham, R. R. G.; Leitch, A. W. R.; Gibbon, T. B.

2017-11-01

In this work, a four-level pulse amplitude modulation (4-PAM) format with a polarization-modulated pulse per second (PPS) clock signal using a single vertical cavity surface emitting laser (VCSEL) carrier is for the first time experimentally demonstrated. We propose uncomplex alternative technique for increasing capacity and flexibility in short-reach optical communication links through multi-signal modulation onto a single VCSEL carrier. A 20 Gbps 4-PAM data signal is directly modulated onto a single mode 10 GHz bandwidth VCSEL carrier at 1310 nm, therefore, doubling the network bit rate. Carrier spectral efficiency is further maximized by exploiting the inherent orthogonal polarization switching of the VCSEL carrier with changing bias in transmission of a PPS clock signal. We, therefore, simultaneously transmit a 20 Gbps 4-PAM data signal and a polarization-based PPS clock signal using a single VCSEL carrier. It is the first time a signal VCSEL carrier is reported to simultaneously transmit a directly modulated 20 Gbps 4-PAM data signal and a polarization-based PPS clock signal. We further demonstrate on the design of a software-defined digital signal processing (DSP)-assisted receiver as an alternative to costly receiver hardware. Experimental results show that a 3.21 km fibre transmission with simultaneous 20 Gbps 4-PAM data signal and polarization-based PPS clock signal introduced a penalty of 3.76 dB. The contribution of polarization-based PPS clock signal to this penalty was found out to be 0.41 dB. Simultaneous distribution of data and timing clock signals over shared network infrastructure significantly increases the aggregated data rate at different optical network units (ONUs), without costly investment.

EAP recordings in ineraid patients--correlations with psychophysical measures and possible implications for patient fitting.

PubMed

Zimmerling, Martin J; Hochmair, Erwin S

2002-04-01

Objective measurements can be helpful for cochlear implant fitting of difficult populations, as for example very young children. One method, the recording of the electrically evoked compound action potential (EAP), measures the nerve recruitment in the cochlea in response to stimulation through the implant. For coding strategies implemented at a moderate stimulation rate of 250 pps per channel, useful correlations between EAP data and psychophysical data have been already found. With new systems running at higher rates, it is important to check these correlations again. This study investigates the correlations between psychophysical data and EAP measures calculated from EAP amplitude growth functions. EAP data were recorded in 12 Ineraid subjects. Additionally, behavioral thresholds (THR) and maximum acceptable loudness levels (MAL) were determined for stimulation rates of 80 pps and 2,020 pps for each electrode. Useful correlations between EAP data and psychophysical data were found at the low stimulation rate (80 pps). However, at the higher stimulation rate (2,020 pps) correlations were not significant. They were improved substantially, however, by introducing a factor that corrected for disparities due to temporal integration. Incorporation of this factor, which controls for the influence of the stimulation rate on the threshold, improved the correlations between EAP measures recorded at 80 pps and psychophysical MALs measured at 2,020 pps to better than r = 0.70. EAP data as such can only be used to predict behavioral THRs or MCLs at low stimulation rates. To cope with temporal integration effects at higher stimulation rates, EAP data must be rate corrected. The introduction of a threshold-rate-factor is a promising way to achieve that goal. Further investigations need to be performed.

Post-polio syndrome. Cases report and review of literature.

PubMed

Pastuszak, Żanna; Stępień, Adam; Tomczykiewicz, Kazimierz; Piusińska-Macoch, Renata; Galbarczyk, Dariusz; Rolewska, Agnieszka

It is estimated that around 15 million people survived polio infection worldwide since early twentieth century. In 1950 effective vaccination was used for first time. Since that time number of affected people decreased. The last epidemic of Haine-Medine disease in Poland was in 1950s. Another rare cases of infections were observed till 1970s. About at least 15 years after polio virus infection, slowly progressive muscle limbs paresis with muscle atrophy, joints pain, paresthesia were observed in polio survivors. That constellation of symptoms was called post-polio syndrome (PPS). PPS frequency among people after paralytic and nonparalytic polio infectious is ranged from 30% to 80%. Fatigue that leads to physical and mental activity deterioration is another important symptom that is observed in 90% of patients with PPS. Etiology of disease remains elusive. Probably it is an effect of spine frontal horns motoneurons damage during acute virus polio infection that leads to overloading and degeneration of remaining ones. The most important risk factors of PPS are female sex and respiratory symptoms during acute polio infection. Electromyography is an important part of PPS diagnostic process. Electrophysiological abnormalities are seen in clinically affected and unaffected muscles. The most frequent are fasciculations and fibrillations during rest activity, extension of motor unit area, time duration and amplitude. In this study we described three cases of people who developed PPS years after Haine-Medine disease and correlation between their EMG results and clinical status. We also analyzed electromyography results both after one month since first PPS signs occurred as well as after few years. Presentation of dynamic changes in EMG was the most important aim of that study. Copyright © 2017. Published by Elsevier Urban & Partner Sp. z o.o.

Preparation and Electrochemical Properties of Graphene/Epoxy Resin Composite Coating

NASA Astrophysics Data System (ADS)

Liao, Zijun; Zhang, Tianchi; Qiao, Sen; Zhang, Luyihang

2017-11-01

The multilayer graphene powder as filler, epoxy modified silicone resin as film-forming agent, anticorrosion composite coating has been created using sand dispersion method, the electrochemical performance was compared with different content of graphene composite coating and pure epoxy resin coating. The open circuit potential (OCP), potentiodynamic polarization curves (Tafel Plot) and electrochemical impedance spectroscopy (EIS) were tested. The test results showed that the anti-corrosion performance of multilayer graphene added has improved greatly, and the content of the 5% best corrosion performance of graphene composite coating.

The crystallization of tough thermoplastic resins in the presence of carbon fibers

NASA Technical Reports Server (NTRS)

Theil, M. H.

1986-01-01

The crystallization kinetics of the thermoplastic resins poly(phenylene sulfide) (PPS) and poly(aryl-ether-ether-ketone) (PEEK) in the presence and in the abscence of carbon fibers was studied. How carbon fiber surfaces in composites affect the crystallization of tough thermoplastic polymers that may serve as matrix resins were determined. The crystallization kinetics of such substances can provide useful information about the crystallization mechanisms and, thus, indicate if the presence of carbon fibers cause any changes in such mechanisms.

Testing for new physics: neutrinos and the primordial power spectrum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Canac, Nicolas; Abazajian, Kevork N.; Aslanyan, Grigor

2016-09-01

We test the sensitivity of neutrino parameter constraints from combinations of CMB and LSS data sets to the assumed form of the primordial power spectrum (PPS) using Bayesian model selection. Significantly, none of the tested combinations, including recent high-precision local measurements of H{sub 0} and cluster abundances, indicate a signal for massive neutrinos or extra relativistic degrees of freedom. For PPS models with a large, but fixed number of degrees of freedom, neutrino parameter constraints do not change significantly if the location of any features in the PPS are allowed to vary, although neutrino constraints are more sensitive to PPSmore » features if they are known a priori to exist at fixed intervals in log k . Although there is no support for a non-standard neutrino sector from constraints on both neutrino mass and relativistic energy density, we see surprisingly strong evidence for features in the PPS when it is constrained with data from Planck 2015, SZ cluster counts, and recent high-precision local measurements of H{sub 0}. Conversely combining Planck with matter power spectrum and BAO measurements yields a much weaker constraint. Given that this result is sensitive to the choice of data this tension between SZ cluster counts, Planck and H{sub 0} measurements is likely an indication of unmodeled systematic bias that mimics PPS features, rather than new physics in the PPS or neutrino sector.« less

Microstructure and thermal properties of copper–diamond composites with tungsten carbide coating on diamond particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Qiping; He, Xinbo, E-mail: xb_he@163.com; Ren, Shubin

2015-07-15

An effective method for preparing tungsten carbide coating on diamond surfaces was proposed to improve the interface bonding between diamond and copper. The WC coating was formed on the diamond surfaces with a reaction medium of WO{sub 3} in mixed molten NaCl–KCl salts and the copper–diamond composites were obtained by vacuum pressure infiltration of WC-coated diamond particles with pure copper. The microstructure of interface bonding between diamond and copper was discussed. Thermal conductivity and thermal expansion behavior of the obtained copper–diamond composites were investigated. Results indicated that the thermal conductivity of as-fabricated composite reached 658 W m{sup −} {sup 1}more » K{sup −} {sup 1}. Significant reduction in coefficient of thermal expansion of the composite compared with that of pure copper was obtained. - Highlights: • WC coating was successfully synthesized on diamond particles in molten salts. • WC coating obviously promoted the wettability of diamond and copper matrix. • WC coating greatly enhanced the thermal conductivity of Cu–diamond composite. • The composites are suitable candidates for heat sink applications.« less

In Situ TiC-Reinforced Ni-Based Composite Coating Prepared by Flame Spraying Using Sucrose as the Source of Carbon

NASA Astrophysics Data System (ADS)

Wang, Haitao; Zhang, Shouquan; Zhu, Jinglei; Huang, Jihua; Liu, Huiyuan; Zhang, Hua

2009-03-01

A Ni-Ti-C composite powder for Reactive Thermal Spraying is made by heating a mixture of titanium, nickel, and sucrose to carbonize the sucrose, which is used as the source of carbon. The carbon obtained by pyrolysis of sucrose is a reactive constituent as well as the binder in the composite powder. The titanium and nickel particles are bound by the carbon to form granules of the composite powder. This powder feedstock was used to prepare in situ TiC-reinforced Ni-based composite coating by oxyacetylene flame spraying. The TiC-Ni composite coating is made of TiC, Ni, and some Ni3Ti. In the coating, a mass of fine TiC particles is uniformly distributed within the metallic matrix. The microhardness and surface hardness of the coating are, respectively, 1433 HV0.2kg and 62 ± 6 (HR30N). The wear resistance is much better for the TiC-Ni composite coating than for the substrate and Ni60 coating.

Comparison of physical characteristics and cell culture test of hydroxyapatite/collagen composite coating on NiTi SMA: electrochemical deposition and chemically biomimetic growth

NASA Astrophysics Data System (ADS)

Hu, Kai; Yang, Xianjin; Cai, Yanli; Cui, Zhenduo; Wei, Qiang

2007-07-01

A hydroxyapatite (HA)/collagen (COL) composite coating on NiTi shape memory alloy (SMA) was prepared by eletrochemical deposition (ELD) in modified simulated body fluid (MSBF). To draw comparisons of physical characteristics and bioactivity of the composite coating, the HA/COL composite coating was also prepared by chemically biomimetic growth (BG) and the ELD coating was re-soaked in MSBF again for further biomimetic growth (called EBG method in this paper). It was indicated that the c-axis of HA crystals was oriented parallel to the longitudinal direction of the COL fibril in BG and EBG coating, which could not found in ELD coating. The EBG method could induce a denser, thicker and better crystallized HA/COL coating. The cell culture test indicated that the BG coating presented better cell biocompatibility.

The Incremental Cost-Effectiveness of Engaging Private Practitioners to Refer Tuberculosis Suspects to DOTS Services in Jogjakarta, Indonesia

PubMed Central

Mahendradhata, Yodi; Probandari, Ari; Ahmad, Riris A.; Utarini, Adi; Trisnantoro, Laksono; Lindholm, Lars; van der Werf, Marieke J.; Kimerling, Michael; Boelaert, Marleen; Johns, Benjamin; Van der Stuyft, Patrick

2010-01-01

We aimed to evaluate the incremental cost-effectiveness of engaging private practitioners (PPs) to refer tuberculosis (TB) suspects to public health centers in Jogjakarta, Indonesia. Effectiveness was assessed for TB suspects notified between May 2004 and April 2005. Private practitioners referred 1,064 TB suspects, of which 57.5% failed to reach a health center. The smear-positive rate among patients reaching a health center was 61.8%. Two hundred eighty (280) out of a total of 1,306 (21.4%) new smear-positive cases were enrolled through the PPs strategy. The incremental cost-effectiveness ratio per smear-positive case successfully treated for the PPs strategy was US$351.66 (95% CI 322.84–601.33). On the basis of an acceptability curve using the National TB control program's willingness-to-pay threshold (US$448.61), we estimate the probability that the PPs strategy is cost-effective at 66.8%. The strategy of engaging PPs was incrementally cost-effective, although under specific conditions, most importantly a well-functioning public directly observed treatment, short-course (DOTS) program. PMID:20519613

Surrogate endpoints for overall survival in advanced non-small-cell lung cancer patients with mutations of the epidermal growth factor receptor gene.

PubMed

Yoshino, Reiko; Imai, Hisao; Mori, Keita; Takei, Kousuke; Tomizawa, Mai; Kaira, Kyoichi; Yoshii, Akihiro; Tomizawa, Yoshio; Saito, Ryusei; Yamada, Masanobu

2014-09-01

Subsequent therapies confound the ability to discern the effect of first-line chemotherapy on overall survival (OS). We investigated whether progression-free survival (PFS), post-progression survival (PPS) and tumor response were valid surrogate endpoints for OS following first-line chemotherapy in individual patients with advanced non-small-cell lung cancer (NSCLC) harboring sensitive epidermal growth factor receptor gene mutations. We retrospectively analyzed 35 patients with advanced NSCLC treated with first-line gefitinib. The associations of PFS, PPS and tumor response with OS were analyzed. PPS was found to be strongly correlated with OS, unlike PFS and tumor shrinkage. The factors significantly associated with PPS were performance status (PS) after first-line treatment, best response to second-line treatment and number of regimens used after disease progression. PPS may be a surrogate for OS in this patient population and further therapy after disease progression following first-line chemotherapy may significantly affect OS. However, a larger study is required to validate these results.

Critical role of dendritic cells in T cell retention in the interfollicular region of Peyer's patches.

PubMed

Obata, Takashi; Shibata, Naoko; Goto, Yoshiyuki; Ishikawa, Izumi; Sato, Shintaro; Kunisawa, Jun; Kiyono, Hiroshi

2013-07-15

Peyer's patches (PPs) simultaneously initiate active and quiescent immune responses in the gut. The immunological function is achieved by the rigid regulation of cell distribution and trafficking, but how the cell distribution is maintained remains to be elucidated. In this study, we show that binding of stromal cell-derived lymphoid chemokines to conventional dendritic cells (cDCs) is essential for the retention of naive CD4(+) T cells in the interfollicular region (IFR) of PPs. Transitory depletion of CD11c(high) cDCs in mice rapidly impaired the IFR structure in the PPs without affecting B cell follicles or germinal centers, lymphoid chemokine production from stromal cells, or the immigration of naive T cells into the IFRs of PPs. The cDC-orchestrated retention of naive T cells was mediated by heparinase-sensitive molecules that were expressed on cDCs and bound the lymphoid chemokine CCL21 produced from stromal cells. These data collectively reveal that interactions among cDCs, stromal cells, and naive T cells are necessary for the formation of IFRs in the PPs.

THE EFFECT OF PLANET-PLANET SCATTERING ON THE SURVIVAL OF EXOMOONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong Yanxiang; Zhou Jilin; Xie Jiwei

2013-05-20

Compared to the giant planets in the solar system, exoplanets have many remarkable properties, such as the prevalence of giant planets on eccentric orbits and the presence of hot Jupiters. Planet-planet scattering (PPS) between giant planets is a possible mechanism to interpret the above and other observed properties. If the observed giant planet architectures are indeed outcomes of PPS, such a drastic dynamical process must affect their primordial moon systems. In this Letter, we discuss the effect of PPS on the survival of exoplanets' regular moons. From an observational viewpoint, some preliminary conclusions are drawn from the simulations. (1) PPSmore » is a destructive process to the moon systems; single planets on eccentric orbits are not ideal moon-search targets. (2) If hot Jupiters formed through PPS, their original moons have little chance of survival. (3) Planets in multiple systems with small eccentricities are more likely to hold their primordial moons. (4) Compared with lower-mass planets, massive planets in multiple systems may not be the preferred moon-search targets if the system underwent a PPS history.« less

Quadriceps muscle strength and voluntary activation after polio.

PubMed

Beelen, Anita; Nollet, Frans; de Visser, Marianne; de Jong, Bareld A; Lankhorst, Gustaaf J; Sargeant, Anthony J

2003-08-01

Quadriceps strength, maximal anatomical cross-sectional area (CSA), maximal voluntary activation (MVA), and maximal relaxation rate (MRR) were studied in 48 subjects with a past history of polio, 26 with and 22 without postpoliomyelitis syndrome (PPS), and in 13 control subjects. It was also investigated whether, apart from CSA, MVA and MRR were determinants of muscle strength. Polio subjects had significantly less strength, CSA, and MRR in the more-affected quadriceps than control subjects. MVA was reduced in 18 polio subjects and normal in all controls. PPS subjects differed from non-PPS subjects only in that the MVA of the more-affected quadriceps was significantly lower. Both CSA and MVA were found to be associated with muscle strength. Quadriceps strength in polio subjects was dependent not only on muscle mass, but also on the ability to activate the muscles. Since impaired activation was more pronounced in PPS subjects, the new muscle weakness and functional decline in PPS may be due not only to a gradual loss of muscle fibers, but also to an increasing inability to activate the muscles.

Astrometric Telescope Facility isolation and pointing study

NASA Technical Reports Server (NTRS)

Hibble, William; Allen, Terry; Jackson, Louis; Medbery, James; Self, Richard

1988-01-01

The Astrometric Telescope Facility (ATF), an optical telescope designed to detect extrasolar planetary systems, is scheduled to be a major user of the Space Station's Payload Pointing System (PPS). However, because the ATF has such a stringent pointing stability specification and requires + or - 180 deg roll about its line of sight, mechanisms to enhance the basic PPS capability are required. The ATF pointing performance achievable by the addition of a magnetic isolation and pointing system (MIPS) between the PPS upper gimbal and the ATF, and separately, by the addition of a passive isolation system between the Space Station and the PPS base was investigated. The candidate MIPS can meet the ATF requirements in the presence of a 0.01 g disturbance. It fits within the available annular region between the PPS and the ATF while meeting power and weight limitations and providing the required roll motion, payload data and power services. By contrast, the passive base isolator system must have an unrealistically low isolation bandwidth on all axes to meet ATF pointing requirements and does not provide roll about the line of sight.

Long-term antibiotic delivery by chitosan-based composite coatings with bone regenerative potential

NASA Astrophysics Data System (ADS)

Ordikhani, F.; Simchi, A.

2014-10-01

Composite coatings with bone-bioactivity and drug-eluting capacity are considered as promising materials for titanium bone implants. In this work, drug-eluting chitosan-bioactive glass coatings were fabricated by a single-step electrophoretic deposition technique. Drug-loading and -releasing capacity of the composite coatings were carried out using the vancomycin antibiotic. Uniform coatings with a thickness of ∼55 μm containing 23.7 wt% bioactive glass particles and various amounts of the antibiotic (380-630 μg/cm2) were produced. The coatings were bioactive in terms of apatite-forming ability in simulated body fluid and showed favorable cell adhesion and growth. In vitro biological tests also indicated that the composite coatings had better cellular affinity than pristine chitosan coatings. The in vitro elution kinetics of the composite coating revealed an initial burst release of around 40% of the drug within the first elution step of 1 h and following by a continuous eluting over 4 weeks, revealing long-term drug-delivering potential. Antibacterial tests using survival assay against Gram-positive Staphylococcus aureus bacteria determined the effect of vancomycin release on reduction of infection risk. Almost no bacteria were survived on the coatings prepared from the EPD suspension containing ≥0.5 g/l vancomycin. The developed chitosan-based composite coatings with bone bioactivity and long-term drug-delivery ability may be potentially useful for metallic implants to reduce infection risk.

Effect of different thickness h-BN coatings on interface shear strength of quartz fiber reinforced Sisbnd Osbnd Csbnd N composite

NASA Astrophysics Data System (ADS)

Wang, Shubin; Zheng, Yu

2014-02-01

Hexagonal boron nitride (h-BN) coatings with different thickness were prepared on quartz fibers to improve mechanical properties of quartz fiber reinforced Sisbnd Osbnd Csbnd N composite. Scanning electron microscopy (SEM), push-out test and single edge notched beam (SENB) in three point bending test were employed to study morphology, interface shear strength and fracture toughness of the composite. The results showed that h-BN coatings changed the crack growth direction and weaken the interface shear strength efficiently. When the h-BN coating was 308.2 nm, the interface shear strength was about 5.2 MPa, which was about one-quarter of that of the sample without h-BN coatings. After the heating process for obtaining composite, the h-BN nanometer-sized grains would grow up to micron-sized hexagonal grains. Different thickness h-BN coatings had different structure. When the coatings were relatively thin, the hexagonal grains were single layer structure, and when the coatings were thicker, the hexagonal grains were multiple layer structure. This multiple layer interface phase would consume more power of cracks, thus interface shear strength of the composite decreased steadily with the increasing of h-BN coatings thickness. When the coating thickness was 238.8 nm, KIC reaches the peak value 3.8 MPa m1/2, which was more than two times of that of composites without h-BN coatings.

A nanometallic nickel-coated, glass-fibre-based structural health monitoring system for polymer composites

NASA Astrophysics Data System (ADS)

Balaji, R.; Sasikumar, M.

2017-09-01

Glass-fibre-reinforced polymer matrix composites are widely used in various industries because of their unique high strength to weight ratio. Unlike metals, strain-induced and damage states of composites are complicated to predict under real-time loading due to their anisotropic nature. With that focus, a piezoresistive nanomaterial-based structural health monitoring system for laminated polymer composites is proposed to measure the strain induced in the composite under real-time loading. Nanometallic nickel-coated glass fibres are embedded into the polymer composites to monitor the strain and damage induced in them. The nanometallic nickel is coated over the glass fibre by a dip coating technique using epoxy as the binding agent. A microcontroller-based electrical resistance measurement system is used to measure the piezoresistive variation in the coated glass fibre under real-time loading. Using the piezoresistance variation of the embedded nanometallic nickel-coated glass fibre, the real-time strain and damage induced in the composite can be correlated. The piezoresistive response of the coated glass fibre is descibed in two phases, the deformation phase and the failure phase, which clearly show the various states of strain and damage induced in the composites.

Laser Cladding of Composite Bioceramic Coatings on Titanium Alloy

NASA Astrophysics Data System (ADS)

Xu, Xiang; Han, Jiege; Wang, Chunming; Huang, Anguo

2016-02-01

In this study, silicon nitride (Si3N4) and calcium phosphate tribasic (TCP) composite bioceramic coatings were fabricated on a Ti6Al4V (TC4) alloy using Nd:YAG pulsed laser, CO2 CW laser, and Semiconductor CW laser. The surface morphology, cross-sectional microstructure, mechanical properties, and biological behavior were carefully investigated. These investigations were conducted employing scanning electron microscope, energy-dispersive x-ray spectroscopy, and other methodologies. The results showed that both Si3N4 and Si3N4/TCP composite coatings were able to form a compact bonding interface between the coating and the substrate by using appropriate laser parameters. The coating layers were dense, demonstrating a good surface appearance. The bioceramic coatings produced by laser cladding have good mechanical properties. Compared with that of the bulk material, microhardness of composite ceramic coatings on the surface significantly increased. In addition, good biological activity could be obtained by adding TCP into the composite coating.

Biomimetic composite coating on rapid prototyped scaffolds for bone tissue engineering.

PubMed

Arafat, M Tarik; Lam, Christopher X F; Ekaputra, Andrew K; Wong, Siew Yee; Li, Xu; Gibson, Ian

2011-02-01

The objective of this present study was to improve the functional performance of rapid prototyped scaffolds for bone tissue engineering through biomimetic composite coating. Rapid prototyped poly(ε-caprolactone)/tri-calcium phosphate (PCL/TCP) scaffolds were fabricated using the screw extrusion system (SES). The fabricated PCL/TCP scaffolds were coated with a carbonated hydroxyapatite (CHA)-gelatin composite via biomimetic co-precipitation. The structure of the prepared CHA-gelatin composite coating was studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Compressive mechanical testing revealed that the coating process did not have any detrimental effect on the mechanical properties of the scaffolds. The cell-scaffold interaction was studied by culturing porcine bone marrow stromal cells (BMSCs) on the scaffolds and assessing the proliferation and bone-related gene and protein expression capabilities of the cells. Confocal laser microscopy and SEM images of the cell-scaffold constructs showed a uniformly distributed cell sheet and accumulation of extracellular matrix in the interior of CHA-gelatin composite-coated PCL/TCP scaffolds. The proliferation rate of BMSCs on CHA-gelatin composite-coated PCL/TCP scaffolds was about 2.3 and 1.7 times higher than that on PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds, respectively, by day 10. Furthermore, reverse transcription polymerase chain reaction and Western blot analysis revealed that CHA-gelatin composite-coated PCL/TCP scaffolds stimulate osteogenic differentiation of BMSCs the most, compared with PCL/TCP scaffolds and CHA-coated PCL/TCP scaffolds. These results demonstrate that CHA-gelatin composite-coated rapid prototyped PCL/TCP scaffolds are promising for bone tissue engineering. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Electroless Cu/Ni Plating on Graphite Flake and the Effects to the Properties of Graphite Flake/Si/Al Hybrid Composites

NASA Astrophysics Data System (ADS)

Huang, Ying; Peng, Xuanyi; Yang, Yiwen; Wu, Haiwei; Sun, Xu; Han, Xiaopeng

2018-03-01

Proper process and parameter were investigated to coat Cu or Ni on graphite flake (Gf) by electroless plating. Microstructural characterization indicated that the Cu/Ni was coated on the Gf uniformly and comprehensively. Then aluminum matrix composites reinforced with Si and graphite were fabricated by a unique vacuum gas pressure infiltration. The thermal conductivity and mechanical properties of the composites, both with and without Cu or Ni coating layers on the graphite surface, have been studied. The obtained results indicated that the mechanical property of the Cu or Ni coated Gf/Si/Al composites dramatically increased, as compared with the non-coated Gf/Si/Al composite. In the meantime, Cu or Ni coated Gf proved to have better wettability and interfacial bonding with the aluminum matrix, which were expected to be a highly sustainable and dispersible reinforcement for metal matrix composites.

Biodegradable Poly(polyol sebacate) Polymers

PubMed Central

Bruggeman, Joost P.; de Bruin, Berend-Jan; Bettinger, Christopher J.; Langer, Robert

2010-01-01

We have developed a family of synthetic biodegradable polymers that are composed of structural units endogenous to the human metabolism, designated poly(polyol sebacates) (PPS) polymers. Material properties of PPS polymers can be tuned by altering the polyol monomer and reacting stiochiometric ratio of sebacic acid. These thermoset networks exhibited tensile Young’s moduli ranging from 0.37 ± 0.08 to 378 ± 33 MPa with maximum elongations at break from 10.90 ± 1.37 to 205.16 ± 55.76%, and glass-transition temperatures ranged from ~7 to 46 °C. In vitro degradation under physiological conditions was slower than in vivo degradation rates observed for some PPS polymers. PPS polymers demonstrated similar in vitro and in vivo biocompatibility compared to poly(L-lactic-co-glycolic acid) (PLGA). PMID:18824260

Effects of Fiber/Matrix Interface and its Composition on Mechanical Properties of Hi-Nicalon/Celsian Composites

NASA Technical Reports Server (NTRS)

Bansal, Narottam P.; Eldridge, Jeffrey I.

1999-01-01

To evaluate the effects of fiber coatings on composite mechanical properties. unidirectional celsian matrix composites reinforced with uncoated Hi-Nicalon fibers and those precoated with a dual BN/SiC layer in two separate batches (batch 1 and batch 2) were tested in three-point flexure. The uncoated-fiber reinforced composites showed catastrophic failure with strength of 210+/-35 MPa and a flat fracture surface. In contrast, composites reinforced with coated fibers exhibited graceful failure with extensive fiber pullout and showed significantly higher ultimate strengths, 904 and 759 MPa for the batch 1 and 2 coatings. respectively. Fiber push-in tests and microscopic examination indicated no chemical reaction at the uncoated or coated fiber-matrix interfaces that might be responsible for fiber strength degradation. Instead, the low strength of composite with uncoated fibers was due to degradation of the fiber strength from mechanical damage during composite processing. Despite identical processing, the first matrix cracking stresses (Sigma(sub mc)) of the composites reinforced with fibers coated in batch 1 and batch 2 were quite different, 436 and 122 MPa, respectively. The large difference in Sigma(sub mc) of the coated-fiber composites was attributed to differences in fiber sliding stresses (Tau(sub friction)), 121.2+/-48.7 and 10.4+/-3.1 MPa, respectively. for the two composites as determined by the fiber push-in method. Such a large difference in Tau(sub friction). for the two composites was found to be due to the difference in the compositions of the interface coatings. Scanning Auger microprobe analysis revealed the presence of carbon layers between the fiber and BN. and also between the BN and SiC coatings in the composite showing lower Tau(sub friction). This resulted in lower Sigma(sub mc) in agreement with the ACK theory. The ultimate strengths of the two composites depended mainly on the fiber volume fraction and were not significantly effected by Tau(sub friction) values, as expected. The poor reproducibility of the fiber coating composition between the two batches was judged to be the primary source of the large differences in performance of the two composites.

Cycle oxidation behavior and anti-oxidation mechanism of hot-dipped aluminum coating on TiBw/Ti6Al4V composites with network microstructure.

PubMed

Li, X T; Huang, L J; Wei, S L; An, Q; Cui, X P; Geng, L

2018-04-10

Controlled and compacted TiAl 3 coating was successfully fabricated on the network structured TiBw/Ti6Al4V composites by hot-dipping aluminum and subsequent interdiffusion treatment. The network structure of the composites was inherited to the TiAl 3 coating, which effectively reduces the thermal stress and avoids the cracks appeared in the coating. Moreover, TiB reinforcements could pin the TiAl 3 coating which can effectively improve the bonding strength between the coating and composite substrate. The cycle oxidation behavior of the network structured coating on 873 K, 973 K and 1073 K for 100 h were investigated. The results showed the coating can remarkably improve the high temperature oxidation resistance of the TiBw/Ti6Al4V composites. The network structure was also inherited to the Al 2 O 3 oxide scale, which effectively decreases the tendency of cracking even spalling about the oxide scale. Certainly, no crack was observed in the coating after long-term oxidation due to the division effect of network structured coating and pinning effect of TiB reinforcements. Interfacial reaction between the coating and the composite substrate occurred and a bilayer structure of TiAl/TiAl 2 formed next to the substrate after oxidation at 973 K and 1073 K. The anti-oxidation mechanism of the network structured coating was also discussed.

Microstructure and Mechanical Properties of Zn-Ni-Al₂O₃ Composite Coatings.

PubMed

Bai, Yang; Wang, Zhenhua; Li, Xiangbo; Huang, Guosheng; Li, Caixia; Li, Yan

2018-05-21

Zn-Ni-Al₂O₃ composite coatings with different Ni contents were fabricated by low-pressure cold spray (LPCS) technology. The effects of the Ni content on the microstructural and mechanical properties of the coatings were investigated. According to X-ray diffraction patterns, the composite coatings were primarily composed of metallic-phase Zn and Ni and ceramic-phase Al₂O₃. The energy-dispersive spectroscopy results show that the Al₂O₃ content of the composite coatings gradually decreased with increasing of Ni content. The cross-sectional morphology revealed thick, dense coatings with a wave-like stacking structure. The process of depositing Zn and Ni particles and Al₂O₃ particles by the LPCS method was examined, and the deposition mechanism was demonstrated to be mechanical interlocking. The bond strength, micro hardness and friction coefficient of the coatings did not obviously change when the Ni content varied. The presence of Al₂O₃ and Ni increased the wear resistance of the composite coatings, which was higher than that of pure Zn coatings, and the wear mechanism was abrasive and adhesive wear.

Moisture effect on mechanical properties of polymeric composite materials

NASA Astrophysics Data System (ADS)

Airale, A. G.; Carello, M.; Ferraris, A.; Sisca, L.

2016-05-01

The influence of moisture on the mechanical properties of fibre-reinforced polymer matrix composites (PMCs) was investigated. Four materials had been take into account considering: both 2×2-Twill woven carbon fibre or glass fibre, thermosetting matrix (Epoxy Resin) or thermoplastic matrix (Polyphenylene Sulfide). The specimens were submitted for 1800 hours to a hygrothermic test to evaluate moisture absorption on the basis of the Fick's law and finally tested to verify the mechanical properties (ultimate tensile strength). The results showed that the absorbed moisture decreases those properties of composites which were dominated by the matrix or the interface, while was not detectable the influence of water on the considered fibre. An important result is that the diffusion coefficient is highest for glass/PPS and lowest for carbon/epoxy composite material. The results give useful suggestions for the design of vehicle components that are exposed to environmental conditions (rain, snow and humidity).

Post-Polio Syndrome

MedlinePlus

... PPS is unknown but experts have offered several theories to explain the phenomenon—ranging from the fatigue ... families. Managing PPS can involve lifestyle changes. Support groups that encourage self-help, group participation, and positive ...

A Comparative Study of the Microstructure, Mechanical Properties and Corrosion Resistance of Ni- or Fe- Based Composite Coatings by Laser Cladding

NASA Astrophysics Data System (ADS)

Wan, M. Q.; Shi, J.; Lei, L.; Cui, Z. Y.; Wang, H. L.; Wang, X.

2018-04-01

Ni- and Fe-based composite coatings were laser cladded on 40Cr steel to improve the surface mechanical property and corrosion resistance, respectively. The microstructure and phase composition were analyzed by x-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) equipped with an energy-dispersive spectrometer (EDS). The micro-hardness, tribological properties and electrochemical corrosion behavior of the coatings were evaluated. The results show that the thickness of both the coatings is around 0.7 mm, the Ni-based coating is mainly composed of γ-(Ni, Fe), FeNi3, Ni31Si12, Ni3B, CrB and Cr7C3, and the Fe-based coating is mainly composed of austenite and (Fe, Cr)7C3. Micro-hardness of the Ni-based composite coating is about 960 HV0.3, much higher than that of Fe-based coating (357.4 HV0.3) and the 40Cr substrate (251 HV0.3). Meanwhile, the Ni-based composite coating possesses better wear resistance than the Fe-based coating validated by the worn appearance and the wear loss. Electrochemical results suggested that Ni-based coating exhibited better corrosion resistance than the Fe-based coating. The 40Cr substrate could be well protected by the Ni-based coating.

Study on influence of Surface roughness of Ni-Al2O3 nano composite coating and evaluation of wear characteristics

NASA Astrophysics Data System (ADS)

Raghavendra, C. R.; Basavarajappa, S.; Sogalad, Irappa

2018-02-01

Electrodeposition is one of the most technologically feasible and economically superior techniques for producing metallic coating. The advancement in the application of nano particles has grabbed the attention in all fields of engineering. In this present study an attempt has been made on the Ni-Al2O3nano particle composite coating on aluminium substrate by electrodeposition process. The aluminium surface requires a specific pre-treatment for better adherence of coating. In light of this a thin zinc layer is coated on the aluminium substrate by electroless process. In addition to this surface roughness is an important parameter for any coating method and material. In this work Ni-Al2O3 composite coating were successfully coated by varying the process parameters such as bath temperature, current density and particle loading. The experimentation was performed using central composite design based 20 trials of experiments. The effect of process parameters and surface roughness before and after coating is analyzed on wear rate and coating thickness. The results shown a better wear resistance of Ni-Al2O3 composite electrodeposited coating compared to Ni coating. The particle loading and interaction effect of current density with temperature has greater significant effect on wear rate. The surface roughness is significantly affected the wear behaviour and thickness of coating.

In vitro degradation, hemolysis, and cytocompatibility of PEO/PLLA composite coating on biodegradable AZ31 alloy.

PubMed

Wei, Zhongling; Tian, Peng; Liu, Xuanyong; Zhou, Bangxin

2015-02-01

Magnesium and its alloys have large potential as degradable and absorbable biomaterials because of their mechanical properties and biocompatibility. However, their corrosion resistance is usually inadequate especially in physiological environment, which limits their broad applications in biomedical areas. In this work, plasma electrolytic oxidized/poly(l-lactide) (PEO/PLLA) composite coating was successfully fabricated on biodegradable AZ31 alloy by combing PEO process and sealing with PLLA. The microstructure, elemental composition, and phase composition of the PEO/PLLA composite coating were investigated. The in vitro degradation of the PEO/PLLA composite coating in simulated body fluid (SBF) was also systematically evaluated. The results revealed that the PEO/PLLA composite coating improved the corrosion resistance of AZ31 alloy significantly. The corrosion potential shifted from -1.663V to more positive position -1.317 V and the corrosion current density was reduced with six-order of magnitude. The Mg(2+) ions, hydrogen release, and pH value change of solution caused by degradation were all decreased significantly. Moreover, the PEO process played a critical role in sustaining the integrity of the implant in long-term service. The result of hemolysis test showed that the PEO/PLLA composite coating vested AZ31 alloy a low hemolysis ratio (0.806 ± 0.771)%, which is much lower than the safe value of 5% according to ISO 10993-4. For the cytocompatibility test, compared with bare AZ31 alloy and PEO coating, MC3T3-E1 cells showed much better adhesion and proliferation on the PEO/PLLA composite coating with nearly 4-fold increase of cells after 7-day cultivation, indicating that the PEO/PLLA composite coating has good biocompatibility for biomedical applications. © 2014 Wiley Periodicals, Inc.

Interfacial microstructure and mechanical properties of Cf/AZ91D composites with TiO2 and PyC fiber coatings.

PubMed

Li, Shaolin; Qi, Lehua; Zhang, Ting; Ju, Luyan; Li, Hejun

2017-10-01

In spite of the effectiveness of the fiber coatings on interface modification of carbon fiber reinforced magnesium matrix composites, the cost and exclusive equipment for the coatings preparation are usually ignored during research work. In this paper, pyrolytic carbon (PyC) and TiO 2 were coated on carbon fiber surface to study the effects of fiber coatings on interfacial microstructure and mechanical properties of carbon fiber reinforced AZ91D composites (C f /AZ91D composites). It was indicated that both the two coatings could modify the interface and improve the mechanical properties of the composites. The ultimate tensile strength of the TiO 2 -C f /AZ91D and the PyC-C f /AZ91D composite were 333MPa and 400MPa, which were improved by 41.7% and 70.2% respectively, compared with the untreated-C f /AZ91D composite. The microstructure observation revealed that the strengthening of the composites relied on fiber integrity and moderate interfacial bonding. MgO nano-particles were generated at the interface due to the reaction of TiO 2 with Mg in the TiO 2 -C f /AZ91D composite. The volume expansion resulting from the reaction let to disordered intergranular films and crystal defects at the interface. The fibers were protected and the interfacial reaction was restrained by PyC coating in the PyC-C f /AZ91D composite. The principle to select the coating of fiber was proposed by comparing the effectiveness and cost of the coatings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dual keel Space Station payload pointing system design and analysis feasibility study

NASA Technical Reports Server (NTRS)

Smagala, Tom; Class, Brian F.; Bauer, Frank H.; Lebair, Deborah A.

1988-01-01

A Space Station attached Payload Pointing System (PPS) has been designed and analyzed. The PPS is responsible for maintaining fixed payload pointing in the presence of disturbance applied to the Space Station. The payload considered in this analysis is the Solar Optical Telescope. System performance is evaluated via digital time simulations by applying various disturbance forces to the Space Station. The PPS meets the Space Station articulated pointing requirement for all disturbances except Shuttle docking and some centrifuge cases.

Prototyping Of Patterned Functional Nanostructures

DOEpatents

Fan, Hongyou; Lopez, Gabriel P.; Brinker, Charles Jeffrey; Lu, Yunfeng

2002-10-29

The present invention provides a coating composition comprising: A coating composition comprising: TEOS; a surfactant; at least one organosilane; HCl; water; and ethanol. The present invention also provides films made from such a coating composition and a method for making such films.

Mg-MOF-74/MgF2 Composite Coating for Improving the Properties of Magnesium Alloy Implants: Hydrophilicity and Corrosion Resistance

PubMed Central

Liu, Wei; Yan, Zhijie; Ma, Xiaolu; Geng, Tie; Wu, Haihong

2018-01-01

Surface modification on Mg alloys is highly promising for their application in the field of bone repair. In this study, a new metal–organic framework/MgF2 (Mg-MOF-74/MgF2) composite coating was prepared on the surface of AZ31B Mg alloy via pre-treatment of hydrofluoric acid and in situ hydrothermal synthesis methods. The surface topography of the composite coating is compact and homogeneous, and Mg-MOF-74 has good crystallinity. The corrosion resistance of this composite coating was investigated through Tafel polarization test and immersion test in simulated body fluid at 37 °C. It was found that Mg-MOF-74/MgF2 composite coating significantly slowed down the corrosion rate of Mg alloy. Additionally, Mg-MOF-74/MgF2 composite coating expresses super-hydrophilicity with the water contact angle of nearly 0°. In conclusion, on the basis of MgF2 anticorrosive coating, the introduction of Mg-MOF-74 further improves the biological property of Mg alloys. At last, we propose that the hydrophilicity of the composite coating is mainly owing to the large number of hydroxyl groups, the high specific surface area of Mg-MOF-74, and the rough coating produced by Mg-MOF-74 particles. Hence, Mg-MOF-74 has a great advantage in enhancing the hydrophilicity of Mg alloy surface. PMID:29518933

Mg-MOF-74/MgF₂ Composite Coating for Improving the Properties of Magnesium Alloy Implants: Hydrophilicity and Corrosion Resistance.

PubMed

Liu, Wei; Yan, Zhijie; Ma, Xiaolu; Geng, Tie; Wu, Haihong; Li, Zhongyue

2018-03-07

Surface modification on Mg alloys is highly promising for their application in the field of bone repair. In this study, a new metal-organic framework/MgF₂ (Mg-MOF-74/MgF₂) composite coating was prepared on the surface of AZ31B Mg alloy via pre-treatment of hydrofluoric acid and in situ hydrothermal synthesis methods. The surface topography of the composite coating is compact and homogeneous, and Mg-MOF-74 has good crystallinity. The corrosion resistance of this composite coating was investigated through Tafel polarization test and immersion test in simulated body fluid at 37 °C. It was found that Mg-MOF-74/MgF₂ composite coating significantly slowed down the corrosion rate of Mg alloy. Additionally, Mg-MOF-74/MgF₂ composite coating expresses super-hydrophilicity with the water contact angle of nearly 0°. In conclusion, on the basis of MgF₂ anticorrosive coating, the introduction of Mg-MOF-74 further improves the biological property of Mg alloys. At last, we propose that the hydrophilicity of the composite coating is mainly owing to the large number of hydroxyl groups, the high specific surface area of Mg-MOF-74, and the rough coating produced by Mg-MOF-74 particles. Hence, Mg-MOF-74 has a great advantage in enhancing the hydrophilicity of Mg alloy surface.

Preparation and characterisation of titania/hydroxyapatite composite coatings obtained by sol-gel process.

PubMed

Milella, E; Cosentino, F; Licciulli, A; Massaro, C

2001-06-01

In the present work a titania network encapsulating a hydroxyapatite particulate phase is proposed as a bioceramic composite coating. The coating on a titanium substrate was produced starting from a sol containing a mixture of titania colloidal particles and hydroxyapatite submicron particles using the dip-coating technique. The microstructure, the morphology and the surface chemical composition of the coating were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. Adhesion tests were also performed. These analyses showed that the obtained coating was chemically clean, homogeneous, rough, porous, with a low thickness and well-defined phase composition as well as a good adhesion to the substrate.

Surface Properties of the IN SITU Formed Ceramics Reinforced Composite Coatings on TI-3AL-2V Alloys

NASA Astrophysics Data System (ADS)

Liu, Peng; Guo, Wei; Hu, Dakui; Luo, Hui; Zhang, Yuanbin

2012-04-01

The synthesis of hard composite coating on titanium alloy by laser cladding of Al/Fe/Ni+C/Si3N4 pre-placed powders has been investigated in detail. SEM result indicated that a composite coating with metallurgical joint to the substrate was formed. XRD result indicated that the composite coating mainly consisted of γ-(Fe, Ni), FeAl, Ti3Al, TiC, TiNi, TiC0.3N0.7, Ti2N, SiC, Ti5Si3 and TiNi. Compared with Ti-3Al-2V substrate, an improvement of the micro-hardness and the wear resistance was observed for this composite coating.

A phenomenological model of coating/substrate adhesion and interfacial bimetallic peeling stress in composite mirrors

NASA Technical Reports Server (NTRS)

Mcelroy, Paul M.; Lawson, Daniel D.

1990-01-01

Adhesion and interfacial stress between metal films and structural composite material substrates is discussed. A theoretical and conceptual basis for selecting coating materials for composite mirror substrates is described. A phenomenological model that interrelates cohesive tensile strength of thin film coatings and interfacial peeling stresses is presented. The model serves as a basis in determining gradiated materials response and compatibility of composite substrate and coating combinations. Parametric evaluation of material properties and geometrical factors such as coating thickness are used to determine the threshold stress levels for maintaining adhesion at the different interfaces.

Preparation and corrosion resistance of magnesium phytic acid/hydroxyapatite composite coatings on biodegradable AZ31 magnesium alloy.

PubMed

Zhang, Min; Cai, Shu; Zhang, Feiyang; Xu, Guohua; Wang, Fengwu; Yu, Nian; Wu, Xiaodong

2017-06-01

In this work, a magnesium phytic acid/hydroxyapatite composite coating was successfully prepared on AZ31 magnesium alloy substrate by chemical conversion deposition technology with the aim of improving its corrosion resistance and bioactivity. The influence of hydroxyapatite (HA) content on the microstructure and corrosion resistance of the coatings was investigated. The results showed that with the increase of HA content in phytic acid solution, the cracks on the surface of the coatings gradually reduced, which subsequently improved the corrosion resistance of these coated magnesium alloy. Electrochemical measurements in simulated body fluid (SBF) revealed that the composite coating with 45 wt.% HA addition exhibited superior surface integrity and significantly improved corrosion resistance compared with the single phytic acid conversion coating. The results of the immersion test in SBF showed that the composite coating could provide more effective protection for magnesium alloy substrate than that of the single phytic acid coating and showed good bioactivity. Magnesium phytic acid/hydroxyapatite composite, with the desired bioactivity, can be synthesized through chemical conversion deposition technology as protective coatings for surface modification of the biodegradable magnesium alloy implants. The design idea of the new type of biomaterial is belong to the concept of "third generation biomaterial". Corrosion behavior and bioactivity of coated magnesium alloy are the key issues during implantation. In this study, preparation and corrosion behavior of magnesium phytic acid/hydroxyapatite composite coatings on magnesium alloy were studied. The basic findings and significance of this paper are as follows: 1. A novel environmentally friendly, homogenous and crack-free magnesium phytic acid/hydroxyapatite composite coating was fabricated on AZ31 magnesium alloy via chemical conversion deposition technology with the aim of enhancing its corrosion resistance and bioactivity. The chemical conversion coatings, which are formed through the reaction between the substrate and the environment, have attracted increasing attention owing to the relative low treatment temperature, favorable bonding to substrate and simple implementation process. 2. With the increasing of hydroxyapatite (HA) content, the crack width in the composite coatings and the thickness of the coatings exhibit obviously decreased. The reason is probably that when adding HA into the phytic acid solution, the amount of active hydroxyl groups in the phytic acid are reduced via forming the coordination bond between P-OH groups from phytic acid and P-OH groups from the surface of HA, thus decreasing the coating thickness and hydrogen formation, as well as avoiding coating cracking. 3. By adjusting the HA content to 45 wt.%, a dense and relatively smooth composite coating with ~1.4 μm thickness is obtained on magnesium alloy, and exhibits high corrosion resistance and good bioactivity when compared with the single phytic acid conversion coating.

Nanoparticle/Polymer Nanocomposite Bond Coat or Coating

NASA Technical Reports Server (NTRS)

Miller, Sandi G.

2011-01-01

This innovation addresses the problem of coatings (meant to reduce gas permeation) applied to polymer matrix composites spalling off in service due to incompatibility with the polymer matrix. A bond coat/coating has been created that uses chemically functionalized nanoparticles (either clay or graphene) to create a barrier film that bonds well to the matrix resin, and provides an outstanding barrier to gas permeation. There is interest in applying clay nanoparticles as a coating/bond coat to a polymer matrix composite. Often, nanoclays are chemically functionalized with an organic compound intended to facilitate dispersion of the clay in a matrix. That organic modifier generally degrades at the processing temperature of many high-temperature polymers, rendering the clay useless as a nano-additive to high-temperature polymers. However, this innovation includes the use of organic compounds compatible with hightemperature polymer matrix, and is suitable for nanoclay functionalization, the preparation of that clay into a coating/bondcoat for high-temperature polymers, the use of the clay as a coating for composites that do not have a hightemperature requirement, and a comparable approach to the preparation of graphene coatings/bond coats for polymer matrix composites.

Article with buffer layer and method of making the same

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCamy, James W.; Ma, Zhixun; Kabagambe, Benjamin

A method of forming a coating layer on a glass substrate in a glass manufacturing process includes: providing a first coating precursor material for a selected coating layer composition to at least one multislot coater to form a first coating region of the selected coating layer; and providing a second coating precursor material for the selected coating layer composition to the multislot coater to form a second coating region of the selected coating layer over the first region. The first coating precursor material is different than the second precursor coating material.

A leadership initiative to improve communication and enhance safety.

PubMed

Donahue, Moreen; Miller, Matthew; Smith, Lisa; Dykes, Patricia; Fitzpatrick, Joyce J

2011-01-01

The EMPOWER project was a collaborative effort to promote a culture of patient safety at Danbury Hospital through an interdisciplinary leadership-driven communication program. The "EMPOWER" component includes Educating and Mentoring Paraprofessionals On Ways to Enhance Reporting of changes in patient status. Specifically, the EMPOWER program was designed to prepare paraprofessional staff (PPS) to communicate changes in patient status using SBAR (situation, background, assessment, recommendations) structured communication. The specific project goals included (a) translation of SBAR structured communication methods for use with PPS, (b) reduction of cultural and educational barriers to interdisciplinary communication, and (c) examination of the effect of the EMPOWER intervention on the PPS communication practices and perceptions of the patient safety culture. Results of the project indicate a change in the use of SBAR throughout the institution, with particular improvement in communication from PPS to professional staff.

The role of Medicare reimbursement in contemporary hospital finance.

PubMed

Golub, S

1986-01-01

A hospital, while performing its major function of providing health care, is also viewed as a business. It needs capital from a wide variety of sources, many of which are government regulated. Over the past few years, federal expenditures for Medicare have increased dramatically, as has regulation of hospital revenue sources. Congress enacted the Medicare Prospective Payment System (PPS) to curb hospital cost inflation. This Note examines historical trends in health care financing and analyzes the Medicare reimbursement system, with emphasis on PPS and its impact on hospital revenues. The Note suggests that hospitals, due to the effects of PPS, will be forced to reduce their levels of financial leverage and will have to look for corporate financial alternatives. PPS may signal a new era in hospital finance. Survival mandates an increased focus on efficient corporate, financial and managerial policies.

Parapharyngeal space tumors: another consideration for otalgia and temporomandibular disorders.

PubMed

Grosskopf, Courtney C; Kuperstein, Arthur S; O'Malley, Bert W; Sollecito, Thomas P

2013-05-01

Parapharyngeal space (PPS) tumors are rare, accounting for 0.5% of all head and neck neoplasms. PPS tumors are difficult to diagnose due to limited presenting signs and symptoms and because of their location deep within the neck. A 60-year-old woman presented with complaints of otalgia, which appeared to be consistent with a temporomandibular disorder (TMD). Due to disproportionate symptoms, an MRI of the temporomandibular joints was ordered. The MRI revealed a mass within the PPS, which was later diagnosed as a mucoepidermoid carcinoma. A literature search failed to reveal otalgia, and facial pain, thought to be related to a TMD, as the primary presenting symptoms of a PPS neoplasm. Patients presenting with disproportionate signs and symptoms of a TMD should be evaluated with advanced imaging to rule out occult pathology. Copyright © 2012 Wiley Periodicals, Inc.

Prospective clinical evaluation of the Polyperf® Safe, a safety Huber needle, in cancer patients.

PubMed

Goossens, Godelieve A; Moons, Philip; Jérôme, Martine; Stas, Marguerite

2011-01-01

Evaluation of the Polyperf® Safe (PPS) needle on safety and user-friendliness, as experienced by first-time and non-first-time users of the device. A prospective, descriptive study was carried out at the University Hospitals Leuven, Belgium. Five hundred PPS needles were individually evaluated in cancer patients. Different aspects of the PPS were assessed: packaging, needle insertion, and needle removal. Nurses were asked whether they had previously inserted or removed this type of needle. We compared the PPS needle with the standard Gripper® needle in terms of safety, ease of use, and ease of training. Three hundred sixty-six evaluation forms were available for analysis (73.2%). Packaging and access evaluations were scored positively, except for two aspects: (1) needle stability, and (2) ease of dressing. Ease of removal was scored unsatisfactory in up to 22.4% of the registrations. Pain at insertion was reported in about 20% registrations, and blood contact was reported by 2.5% of non-first-time users. Safety was scored as good, although ease of use and ease in training scored 25.4% and 43.8%, respectively, lower than the Gripper®. In general, nurses evaluated the PPS positively, with the exception of needle stability, ease of dressing, and ease of removal. No needlestick accidents were recorded. Aspects of ease of use and ease of training for PPS needles scored less than those for the Gripper® needles in up to one-third of the registrations.

ROS-Responsive Microspheres for On Demand Antioxidant Therapy in a Model of Diabetic Peripheral Arterial Disease

PubMed Central

Poole, KM; Nelson, CE; Joshi, RV; Martin, JR; Gupta, MK; Haws, SC; Kavanaugh, TE; Skala, MC; Duvall, CL

2014-01-01

A new microparticle-based delivery system was synthesized from reactive oxygen species (ROS)-responsive poly(propylene sulfide) (PPS) and tested for “on demand” antioxidant therapy. PPS is hydrophobic but undergoes a phase change to become hydrophilic upon oxidation and thus provides a useful platform for ROS-demanded drug release. This platform was tested for delivery of the promising anti-inflammatory and antioxidant therapeutic molecule curcumin, which is currently limited in use in its free form due to poor pharmacokinetic properties. PPS microspheres efficiently encapsulated curcumin through oil-in-water emulsion and provided sustained, on demand release that was modulated in vitro by hydrogen peroxide concentration. The cytocompatible, curcumin-loaded microspheres preferentially targeted and scavenged intracellular ROS in activated macrophages, reduced in vitro cell death in the presence of cytotoxic levels of ROS, and decreased tissue-level ROS in vivo in the diabetic mouse hind limb ischemia model of peripheral arterial disease. Interestingly, due to the ROS scavenging behavior of PPS, the blank microparticles also showed inherent therapeutic properties that were synergistic with the effects of curcumin in these assays. Functionally, local delivery of curcumin-PPS microspheres accelerated recovery from hind limb ischemia in diabetic mice, as demonstrated using non-invasive imaging techniques. This work demonstrates the potential for PPS microspheres as a generalizable vehicle for ROS-demanded drug release and establishes the utility of this platform for improving local curcumin bioavailability for treatment of chronic inflammatory diseases. PMID:25522975

Poly(1,3-propylene sebacate) and Poly(sebacoyl diglyceride): A Pair of Potential Polymers for the Proliferation and Differentiation of Retinal Progenitor Cells.

PubMed

Ni, Ni; Ji, Jing; Chen, Shuo; Zhang, Dandan; Wang, Zi; Shen, Bingqiao; Guo, Chunyu; Zhang, Yi; Wang, Shaofei; Fan, Xianqun; You, Zhengwei; Luo, Min; Gu, Ping

2016-09-01

Using suitable polymers as a carrier for growing and delivering retinal progenitor cells (RPCs) is a promising therapeutic strategy in retinal cell-replacement therapy. Herein recently developed polymer, poly(sebacoyl diglyceride) (PSeD), is selected and its nonhydroxylized counterpart poly(1,3-propylene sebacate) (PPS) is designed to evaluate their potentials for RPC growth and future RPC application. The structures and mechanical properties of the polymers are characterized. The cytocompatibility and effects of these polymers on RPC proliferation, differentiation, and migration are systematically investigated in vitro. Our data show that PPS and PSeD display excellent cytocompatibility with low expression of inflammation and apoptosis factors, which benefit RPC growth. In proliferation assays reveal that RPCs expands well on the polymers, but PPS performs the best for RPC expansion, indicating that PPS can remarkably promote RPC proliferation. In differentiation conditions, RPCs grown on PSeD are more likely to differentiate toward retinal neurons, including photoreceptors, the most interesting type of cells for retinal cell-replacement therapy. Additionally, our results demonstrate that RPCs grown on PSeD display an outstanding ability to migrate. In conclusion, PPS can markedly promote RPC proliferation, whereas PSeD can enhance RPC differentiation toward retinal neurons, suggesting that PSeD and PPS have potential applications in future retinal cell-replacement therapies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Charting a path forward: policy analysis of China's evolved DRG-based hospital payment system

PubMed Central

Liu, Rui; Shi, Jianwei; Yang, Beilei; Jin, Chunlin; Sun, Pengfei; Wu, Lingfang; Yu, Dehua; Xiong, Linping; Wang, Zhaoxin

2017-01-01

Abstract Background At present, the diagnosis-related groups-based prospective payment system (DRG-PPS) that has been implemented in China is merely a prototype called the simplified DRG-PPS, which is known as the ‘ceiling price for a single disease’. Given that studies on the effects of a simplified DRG-PPS in China have usually been controversial, we aim to synthesize evidence examining whether DRGs can reduce medical costs and length of stay (LOS) in China. Methods Data were searched from both Chinese [Wan Fang and China National Knowledge Infrastructure Database (CNKI)] and international databases (Web of Science and PubMed), as well as the official websites of Chinese health departments in the 2004–2016 period. Only studies with a design that included both experimental (with DRG-PPS implementation) and control groups (without DRG-PPS implementation) were included in the review. Results The studies were based on inpatient samples from public hospitals distributed in 12 provinces of mainland China. Among them, 80.95% (17/21) revealed that hospitalization costs could be reduced significantly, and 50.00% (8/16) indicated that length of stay could be decreased significantly. In addition, the government reports showed the enormous differences in pricing standards and LOS in various provinces, even for the same disease. Conclusions We conclude that the simplified DRGs are useful in controlling hospitalization costs, but they fail to reduce LOS. Much work remains to be done in China to improve the simplified DRG-PPS. PMID:28911128

LDEF-space environmental effects on materials: Composites and silicone coatings

NASA Technical Reports Server (NTRS)

Petrie, Brian C.

1992-01-01

The effects of long term low Earth orbit environments on thermal control coatings and organic matrix/fiber reinforced composites are discussed. Two diverse categories are reported here: silicone coatings and composites. For composites physical and structural properties were analyzed; results are reported on mass/dimensional loss, microcracking, short beam shear, coefficient of thermal expansion (CTE), and flexural properties. The changes in thermal control properties, mass, and surface chemistry and morphology are reported and analyzed for the silicone coatings.

LDEF-space environmental effects on materials: Composites and silicone coatings

NASA Technical Reports Server (NTRS)

Petrie, Brian C.

1991-01-01

The objective of the Lockheed experiment is to evaluate the effects of long term low Earth orbit environments on thermal control coatings and organic matrix/fiber reinforced composites. Two diverse categories are reported: silicone coatings and composites. For composites physical and structural properties were analyzed; results are reported on mass/dimensional loss, microcracking, short beam shear, CTE, and flexural properties. The changes in thermal control properties, mass, and surface chemistry and morphology are reported and analyzed for the silicon coatings.

Effect of ceramic coating by aerosol deposition on abrasion resistance of a resin composite material.

PubMed

Taira, Yohsuke; Hatono, Hironori; Mizukane, Masahiro; Tokita, Masahiro; Atsuta, Mitsuru

2006-12-01

Aerosol deposition (AD coating) is a novel technique to coat solid substances with a ceramic film. The purpose of the present study was to investigate the effect of AD coating on abrasion resistance of a resin composite material. A 5-microm-thick aluminum oxide layer was created on the polymerized resin composite. The specimen was cyclically abraded using a toothbrush abrasion simulator for 100,000 cycles. Abraded surface was then measured with a profilometer to determine the average roughness (Ra) and maximum roughness (Rmax). It was found that abrasion cycling increased the Ra value of the No-AD-coating group, but decreased the Ra and Rmax values of the AD coating group. Moreover, the AD coating group showed significantly smaller Ra and Rmax values after 100,000 abrasion cycles as compared to the No-coating control group. Microscopic observation supported these findings. In conclusion, the resistance of the resin composite against toothbrush abrasion was improved by AD coating.

Impact Resistance of EBC Coated SiC/SiC Composites

NASA Technical Reports Server (NTRS)

Fox, Dennis S.; Bhatt, Ramakrishna T.; Choi, Sung R.; Cosgriff, Laura M.; Fox, Dennis s.; Lee, Kang N.

2008-01-01

Impact performance of 2-D woven SiC/SiC composites coated with 225 and 525 m thick environmental barrier coating (EBC) was investigated. The composites were fabricated by melt infiltration and the EBC was deposited by plasma spray. Impact tests were conducted at room temperature and at 1316 C in air using 1.59-mm diameter steel-balls at projectile velocities ranging from 110 to 375 m/s. Both microscopy and nondestructive evaluation (NDE) methods were used to determine the extent of damage in the substrate and coating with increasing projectile velocity. The impacted specimens were tensile tested at room temperature to determine their residual mechanical properties. At projectile velocities less than 125 m/s, no detectable damage was noticed in the MI SiC/SiC composites coated with 525 m EBC. With increase in projectile velocity beyond this value, spallation of EBC layers, delamination of fiber plies, and fiber fracture were detected. At a fixed projectile velocity, the composites coated with 525 m EBC showed less damage than the composite coated with 225 m EBC. Both types of EBC coated composites retained a large fraction of the baseline properties of as-fabricated composites and exhibited non-brittle failure after impact testing at projectile velocities up to 375 m/s. Exposure of impact tested specimens in a moisture environment at 1316 C for 500 hr indicated that the through-the-thickness cracks in the EBC coating and delamination cracks in the substrate generated after impact testing acted as conduits for internal oxidation.

Association of Medicare's Bundled Payment Reform With Changes in Use of Vitamin D Among Patients Receiving Maintenance Hemodialysis: An Interrupted Time-Series Analysis.

PubMed

Spoendlin, Julia; Schneeweiss, Sebastian; Tsacogianis, Theodore; Paik, Julie M; Fischer, Michael A; Kim, Seoyoung C; Desai, Rishi J

2018-06-08

Medicare's 2011 prospective payment system (PPS) was introduced to curb overuse of separately billable injectable drugs. After epoietin, intravenous (IV) vitamin D analogues are the biggest drug cost drivers in hemodialysis (HD) patients, but the association between PPS introduction and vitamin D therapy has been scarcely investigated. Interrupted time-series analyses. Adult US HD patients represented in the US Renal Data System between 2008 and 2013. PPS implementation. The cumulative dose of IV vitamin D analogues (paricalcitol equivalents) per patient per calendar quarter in prevalent HD patients. The average starting dose of IV vitamin D analogues and quarterly rates of new vitamin D use (initiations/100 person-months) in incident HD patients within 90 days of beginning HD therapy. Segmented linear regression models of the immediate change and slope change over time of vitamin D use after PPS implementation. Among 359,600 prevalent HD patients, IV vitamin D analogues accounted for 99% of the total use, and this trend was unchanged over time. PPS resulted in an immediate 7% decline in the average dose of IV vitamin D analogues (average baseline dose = 186.5 μg per quarter; immediate change = -13.5 μg [P < 0.001]; slope change = 0.43 per quarter [P = 0.3]) and in the starting dose of IV vitamin D analogues in incident HD patients (average baseline starting dose = 5.22 μg; immediate change = -0.40 μg [P < 0.001]; slope change = -0.03 per quarter [P = 0.03]). The baseline rate of vitamin D therapy initiation among 99,970 incident HD patients was 44.9/100 person-months and decreased over time, even before PPS implementation (pre-PPS β = -0.46/100 person-months [P < 0.001]; slope change = -0.19/100 person-months [P = 0.2]). PPS implementation was associated with an immediate change in initiation levels (by -4.5/100 person-months; P < 0.001). Incident HD patients were restricted to those 65 years or older. PPS implementation was associated with a 7% reduction in the average dose and starting dose of IV vitamin D analogues and a 10% reduction in the rate of vitamin D therapy initiation. Copyright © 2018 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Depolarizing Effects of Daikenchuto on Interstitial Cells of Cajal from Mouse Small Intestine

PubMed Central

Kim, Hyungwoo; Kim, Hyun Jung; Yang, Dongki; Jung, Myeong Ho; Kim, Byung Joo

2017-01-01

Background: Daikenchuto (DKT; TJ-100, TU-100), a traditional herbal medicineis used in modern medicine to treat gastrointestinal (GI) functional disorders. Interstitial cells of Cajal (ICCs) are the pacemaker cells of the GI tract and play important roles in the regulation of GI motility. Objective: The objective of this study was to investigate the effects of DKT on the pacemaker potentials (PPs) of cultured ICCs from murine small intestine. Materials and Methods: Enzymatic digestions were used to dissociate ICCs from mouse small intestine tissues. All experiments on ICCs were performed after 12 h of culture. The whole-cell patch-clamp configuration was used to record ICC PPs (current clamp mode). All experiments were performed at 30-32°C. Results: In current-clamp modeDKT depolarized and concentration-dependently decreased the amplitudes of PPs. Y25130 (a 5-HT3 receptor antagonist) or SB269970 (a 5-HT7 receptor antagonist) did not block DKT-induced PP depolarization, but RS39604 (a 5-HT4 receptor antagonist) did. Methoctramine (a muscarinic M2 receptor antagonist) failed to block DKT-induced PP depolarization, but pretreating 4-diphenylacetoxy-N-methylpiperidine methiodide (a muscarinic M3 receptor antagonist) facilitated blockade of DKT-induced PP depolarization. Pretreatment with an external Ca2+-free solution or thapsigargin abolished PPsand under these conditions, DKT did not induce PP depolarization. Furthermore Ginseng radix and Zingiberis rhizomes depolarized PPs, whereas Zanthoxyli fructus fruit (the third component of DKT) hyperpolarized PPs. Conclusion: These results suggest that DKT depolarizes ICC PPs in an internal or external Ca2+-dependent manner by stimulating 5-HT4 and M3 receptors. Furthermore, the authors suspect that the component in DKT largely responsible for depolarization is probably also a component of Ginseng radix and Zingiberis rhizomes. SUMMARY Daikenchuto (DKT) depolarized and concentration-dependently decreased the amplitudes of pacemaker potentials (PPs)Y25130 (a 5-HT3 receptor antagonist) or SB269970 (a 5-HT7 receptor antagonist) did not block DKT-induced PP depolarization, but RS39604 (a 5-HT4 receptor antagonist) didMethoctramine (a muscarinic M2 receptor antagonist) failed to block DKT-induced PP depolarization, but pretreating 4-DAMP (a muscarinic M3 receptor antagonist) facilitated blockade of DKT-induced PP depolarizationGinseng radix and Zingiberis rhizomes depolarized PPswhereas Zanthoxyli fructus fruit (the third component of DKT) hyperpolarized PPs. Abbreviation used: DKT: Daikenchuto, GI: Gastrointestinal, ICCs: Interstitial cells of Cajal, PPs: Pacemaker Potentials. PMID:28216898

Depolarizing Effects of Daikenchuto on Interstitial Cells of Cajal from Mouse Small Intestine.

PubMed

Kim, Hyungwoo; Kim, Hyun Jung; Yang, Dongki; Jung, Myeong Ho; Kim, Byung Joo

2017-01-01

Daikenchuto (DKT; TJ-100, TU-100), a traditional herbal medicineis used in modern medicine to treat gastrointestinal (GI) functional disorders. Interstitial cells of Cajal (ICCs) are the pacemaker cells of the GI tract and play important roles in the regulation of GI motility. The objective of this study was to investigate the effects of DKT on the pacemaker potentials (PPs) of cultured ICCs from murine small intestine. Enzymatic digestions were used to dissociate ICCs from mouse small intestine tissues. All experiments on ICCs were performed after 12 h of culture. The whole-cell patch-clamp configuration was used to record ICC PPs (current clamp mode). All experiments were performed at 30-32°C. In current-clamp modeDKT depolarized and concentration-dependently decreased the amplitudes of PPs. Y25130 (a 5-HT 3 receptor antagonist) or SB269970 (a 5-HT 7 receptor antagonist) did not block DKT-induced PP depolarization, but RS39604 (a 5-HT 4 receptor antagonist) did. Methoctramine (a muscarinic M 2 receptor antagonist) failed to block DKT-induced PP depolarization, but pretreating 4-diphenylacetoxy-N-methylpiperidine methiodide (a muscarinic M 3 receptor antagonist) facilitated blockade of DKT-induced PP depolarization. Pretreatment with an external Ca 2+ -free solution or thapsigargin abolished PPsand under these conditions, DKT did not induce PP depolarization. Furthermore Ginseng radix and Zingiberis rhizomes depolarized PPs, whereas Zanthoxyli fructus fruit (the third component of DKT) hyperpolarized PPs. These results suggest that DKT depolarizes ICC PPs in an internal or external Ca 2+ -dependent manner by stimulating 5-HT 4 and M 3 receptors. Furthermore, the authors suspect that the component in DKT largely responsible for depolarization is probably also a component of Ginseng radix and Zingiberis rhizomes. Daikenchuto (DKT) depolarized and concentration-dependently decreased the amplitudes of pacemaker potentials (PPs)Y25130 (a 5-HT 3 receptor antagonist) or SB269970 (a 5-HT 7 receptor antagonist) did not block DKT-induced PP depolarization, but RS39604 (a 5-HT 4 receptor antagonist) didMethoctramine (a muscarinic M 2 receptor antagonist) failed to block DKT-induced PP depolarization, but pretreating 4-DAMP (a muscarinic M 3 receptor antagonist) facilitated blockade of DKT-induced PP depolarizationGinseng radix and Zingiberis rhizomes depolarized PPswhereas Zanthoxyli fructus fruit (the third component of DKT) hyperpolarized PPs. Abbreviation used: DKT: Daikenchuto, GI: Gastrointestinal, ICCs: Interstitial cells of Cajal, PPs: Pacemaker Potentials.

Effect of POLYURETHANE/NANO-SiO2 Composites Coating on Thermo-Mechanical Properties of Polyethylene Film

NASA Astrophysics Data System (ADS)

Ching, Yern Chee; Yaacob, Iskandar Idris

2011-06-01

Polyethylene (PE) film was coated with polyurethane/nanosilica composite layer using rod Mayer process. The polyurethane/nanosilica system was prepared by dispersing nanosilica powder into solvent borne polyurethane (PU) binder under vigorous stirring. The silica nanoparticle used has an average diameter of 16 nm, and their weight fraction were varied from 0 % to 14 %. Two different thicknesses of the PU/nanosilica coating layer were fabricated which were about 4 μm and 8 μm. The structure and thermal mechanical features of the nanocomposite coated PE film were characterized by scanning electron microscope (SEM), dynamic mechanical analyzer (DMA), thermogravimetric analyzer (TGA) as well as tensile tests. The results showed that thin layer coating of the PU/nanosilica composite reduced tensile strength of PE substrate slightly. However, the nanocomposite coating of up to 8 μm reduced the elongation % of PE substrate significantly. PU/nanosilica composite coating layer increased the tensile modulus and stiffness of PE substrate. There was no influence of the PU/nanosilica composite coating to the thermal degradation rate of PE film.

Synthesis and characterization of MoS2/Ti composite coatings on Ti6Al4V prepared by laser cladding

NASA Astrophysics Data System (ADS)

Yang, Rongjuan; Liu, Zongde; Wang, Yongtian; Yang, Guang; Li, Hongchuan

2013-02-01

The MoS2/Ti composite coating with sub-micron grade structure has been prepared on Ti6Al4V by laser method under argon protection. The morphology, microstructure, microhardness and friction coefficient of the coating were examined. The results indicated that the molybdenum disulfide was decomposed during melting and resolidification. The phase organization of composite coating mainly consisted of ternary element sulfides, molybdenum sulfides and titanium sulfides. The friction coefficient of and the surface roughness the MoS2/Ti coating were lower than those of Ti6Al4V. The composite coating exhibits excellent adhesion to the substrates, less surface roughness, good wear resistance and harder surface.

Protective coating for alumina-silicon carbide whisker composites

DOEpatents

Tiegs, Terry N.

1989-01-01

Ceramic composites formed of an alumina matrix reinforced with silicon carbide whiskers homogenously dispersed therein are provided with a protective coating for preventing fracture strength degradation of the composite by oxidation during exposure to high temperatures in oxygen-containing atmospheres. The coating prevents oxidation of the silicon carbide whiskers within the matrix by sealing off the exterior of the matrix so as to prevent oxygen transport into the interior of the matrix. The coating is formed of mullite or mullite plus silicon oxide and alumina and is formed in place by heating the composite in air to a temperature greater than 1200.degree. C. This coating is less than about 100 microns thick and adequately protects the underlying composite from fracture strength degradation due to oxidation.

Microstructure and Mechanical Properties of Zn-Ni-Al2O3 Composite Coatings

PubMed Central

Bai, Yang; Wang, Zhenhua; Li, Xiangbo; Huang, Guosheng; Li, Caixia

2018-01-01

Zn-Ni-Al2O3 composite coatings with different Ni contents were fabricated by low-pressure cold spray (LPCS) technology. The effects of the Ni content on the microstructural and mechanical properties of the coatings were investigated. According to X-ray diffraction patterns, the composite coatings were primarily composed of metallic-phase Zn and Ni and ceramic-phase Al2O3. The energy-dispersive spectroscopy results show that the Al2O3 content of the composite coatings gradually decreased with increasing of Ni content. The cross-sectional morphology revealed thick, dense coatings with a wave-like stacking structure. The process of depositing Zn and Ni particles and Al2O3 particles by the LPCS method was examined, and the deposition mechanism was demonstrated to be mechanical interlocking. The bond strength, micro hardness and friction coefficient of the coatings did not obviously change when the Ni content varied. The presence of Al2O3 and Ni increased the wear resistance of the composite coatings, which was higher than that of pure Zn coatings, and the wear mechanism was abrasive and adhesive wear. PMID:29883391

Impact Resistance of Environmental Barrier Coated SiC/SiC Composites

NASA Technical Reports Server (NTRS)

Bhatt, Ramakrishna T.; Choi, Sung R.; Cosgriff, Laura M.; Fox, Dennis S.; Lee, Kang N.

2008-01-01

Impact performance of 2D woven SiC/SiC composites coated with 225 and 525 microns thick environmental barrier coating (EBC) was investigated. The composites were fabricated by melt infiltration and the EBC was deposited by plasma spray. Impact tests were conducted at room temperature and at 1316 C in air using 1.59 mm diameter steel-balls at projectile velocities ranging from 110 to 375 m/s . Both microscopy and non-destructive evaluation (NDE) methods were used to determine the extent of damage in the substrate and coating with increasing projectile velocity. The impacted specimens were tensile tested at room temperature to determine their residual mechanical properties. At projectile velocities less than 125 m/s , no detectable internal damage was noticed in the MI SiC/SiC composites coated with 525 microns EBC. With increase in projectile velocity beyond this value, spallation of EBC layers, delamination of fiber plies, and fiber fracture were detected. At a fixed projectile velocity, the composites coated with 525 microns EBC showed less damage than those coated with 225 microns EBC. Both types of coated composites retained a large fraction of the baseline properties of the as-fabricated composites and exhibited non-brittle failure after impact testing. Furnace exposure of impacted specimens in a moisture environment at 1316 C for 500 h indicated that the through-the-thickness cracks in the coating and delamination cracks in the substrate generated after impact testing acted as conduits for internal oxidation.

Evaluation of antioxidant and immuno-enhancing activities of Purslane polysaccharides in gastric cancer rats.

PubMed

Li, Yunqiao; Hu, Yanke; Shi, Shaojun; Jiang, Lei

2014-07-01

In the last three decades, numerous polysaccharides and polysaccharide-protein complexes have been isolated from plant or animal and used as a promising source of therapeutic agents for cancer. In this study, we examined the effects of Purslane polysaccharides (PPs) on the oxidative injury and immune status in N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric cancer rats. PPs administration (200, 400 or 800mg/kg body weight) could not only increase the body weight, peripheral white blood cells (WBC) count, thymus and spleen indexes, but also remarkably promote splenocytes proliferation of gastric cancer rats. Furthermore, the production of serum cytokines in gastric cancer rats, such as interleukin-2 (IL-2), interleukin-4 (IL-4) and tumor necrosis factor-alpha (TNF-α) was enhanced by PPs treatment. Besides, treatment with PPs was found to provide a dose-dependent protection against MNNG-induced oxidative injury by enhancing SOD, CAT, GSH-Px activities of gastric cancer rats. Taken together, we concluded that enhancement of antioxidants and immune response might be responsible for the anticancer effect of PPs in gastric cancer. Copyright © 2014 Elsevier B.V. All rights reserved.

Validation of a French version of the pure procrastination scale (PPS).

PubMed

Rebetez, Marie My Lien; Rochat, Lucien; Gay, Philippe; Van der Linden, Martial

2014-08-01

Procrastination is a widespread phenomenon that affects everyone's day-to-day life and interferes with the clinical treatment of several psychopathological states. To assess this construct, Steel (2010) developed the Pure Procrastination Scale (PPS), a short scale intended to capture the general notion of dysfunctional delay. The aim of the current study was to present a French version of this questionnaire. To this end, the 12 items of the PPS were translated into French and data were collected from an online survey in a sample of 245 French-speaking individuals from the general population. The results revealed that one item had problematic face validity; it was therefore removed. Exploratory and confirmatory analyses performed on the resulting 11-item version of the French PPS indicated that the scale was composed of two factors ("voluntary delay" and "observed delay") depending on a common, higher-order construct ("general procrastination"). Good internal consistency and test-retest reliability were found. External validity was supported by specific relationships with measures of personality traits, impulsivity, and subjective well-being. The French PPS therefore presents satisfactory psychometric properties and may be considered a reliable and valid instrument for research, teaching and clinical practice. Copyright © 2014 Elsevier Inc. All rights reserved.

Forecasting E > 50-MeV Proton Events with the Proton Prediction System (PPS)

NASA Astrophysics Data System (ADS)

Kahler, S. W.; White, S. M.; Ling, A. G.

2017-12-01

Forecasting solar energetic (E > 10 MeV) particle (SEP) events is an important element of space weather. While several models have been developed for use in forecasting such events, satellite operations are particularly vulnerable to higher-energy (> 50 MeV) SEP events. Here we validate one model, the proton prediction system (PPS), which extends to that energy range. We first develop a data base of E > 50-MeV proton events > 1.0 proton flux units (pfu) events observed on the GOES satellite over the period 1986 to 2016. We modify the PPS to forecast proton events at the reduced level of 1 pfu and run PPS for four different solar input parameters: (1) all > M5 solar X-ray flares; (2) all > 200 sfu 8800-MHz bursts with associated > M5 flares; (3) all > 500 sfu 8800-MHz bursts; and (4) all > 5000 sfu 8800-MHz bursts. For X-ray flare inputs the forecasted event peak intensities and fluences are compared with observed values. The validation contingency tables and skill scores are calculated for all groups and used as a guide to use of the PPS. We plot the false alarms and missed events as functions of solar source longitude.

Liquid Galvanic Coatings for Protection of Imbedded Metals

NASA Technical Reports Server (NTRS)

MacDowell, Louis G. (Inventor); Curran, Joseph J. (Inventor)

2003-01-01

Coating compositions and methods of their use are described herein for the reduction of corrosion in imbedded metal structures. The coatings are applied as liquids to an external surface of a substrate in which the metal structures are imbedded. The coatings are subsequently allowed to dry. The liquid applied coatings provide galvanic protection to the imbedded metal structures. Continued protection can be maintained with periodic reapplication of the coating compositions, as necessary, to maintain electrical continuity. Because the coatings may be applied using methods similar to standard paints, and because the coatings are applied to external surfaces of the substrates in which the metal structures are imbedded, the corresponding corrosion protection may be easily maintained. The coating compositions are particularly useful in the protection of metal-reinforced concrete.

The effect of incorporated self-lubricated BN(h) particles on the tribological properties of Ni-P/BN(h) composite coatings

NASA Astrophysics Data System (ADS)

Hsu, Chih-I.; Hou, Kung-Hsu; Ger, Ming-Der; Wang, Gao-Liang

2015-12-01

Ni-P/BN(h) composite coatings are prepared by means of the conventional electroless plating from the bath containing up to 10.0 g/l of hexagonal boron nitride particles with size 0.5 μm. The Ni-P coating is also prepared as a comparison. Cationic surfactant cetyltrimethylammonium bromide (CTAB) is used to stabilize the electrolyte, and the optimum CTAB concentration resulting in a nonagglomerated dispersion of particles is obtained using a dispersion stability analyzer. Morphology of the coatings and the effect of incorporated particles on coating structure and composition are investigated via scanning electron microscopy, field emission electron probe micro-analyzer and X-ray diffraction analysis. Hardness, roughness, friction coefficient and wear resistance of the coatings are also evaluated using Vickers microhardness tester, atomic force microscopy and ball-on disk machine. The presence of CTAB in the depositing bath has a positive effect on the surface roughness and performance of Ni-P/BN(h) composite coatings. The friction and wear tests results show that incorporation of 14.5 vol% BN(h) particles into the Ni-P coating lowers the coating friction coefficient by about 75% and the wear resistance of the Ni-P composites is approximately 10 times higher than Ni-P coating.

Corrosion and Wear Response of Oxide-Reinforced Nickel Composite Coatings

NASA Astrophysics Data System (ADS)

Tirlapur, Pradeep; Muniprakash, M.; Srivastava, Meenu

2016-07-01

Various grades of fuels are used in automobiles, as a result the engine components are continuously subjected to simultaneous action of corrosion and wear. Ni-SiC composite coating is the most widely investigated and commercialized wear-resistant coating in the automotive industry. However, this coating cannot be used at temperatures above 450 °C due to the tendency of SiC to react with Ni and form brittle silicides. An alternate approach is to use oxide-reinforced coatings. In the present study, zirconia, ZrO2 and, yttria-stabilized zirconia, YSZ-reinforced Ni composite coatings have been developed by electrodeposition method. It was observed from the microhardness studies that there is no significant difference in the values for Ni-SiC and Ni-ZrO2 coatings. The corrosion behavior was evaluated using polarization and electrochemical impedance studies. The studies showed that oxide particle-reinforced Ni coatings possessed better corrosion resistance due to their lower corrosion current density, I corr. Tribo-corrosion studies were carried out to understand the synergistic effect of wear and corrosion on the performance of Ni-based composite coatings in 0.5 M Na2SO4. Among various composite coatings, Ni-YSZ exhibited less material loss thereby showing better tribo-corrosion behavior.

Organic matrix composite protective coatings for space applications

NASA Technical Reports Server (NTRS)

Dursch, Harry W.; George, Pete

1995-01-01

Successful use of composites in low earth orbit (LEO) depends on their ability to survive long-term exposure to atomic oxygen (AO), ultraviolet radiation, charged particle radiation, thermal cycling, and micrometeoroid and space debris. The AO environment is especially severe for unprotected organic matrix composites surfaces in LEO. Ram facing unprotected graphite/epoxy flown on the 69-month Long Duration Exposure Facility (LDEF) mission lost up to one ply of thickness (5 mils) resulting in decreased mechanical properties. The expected AO fluence of the 30 year Space Station Alpha mission is approximately 20 times that seen on LDEF. This exposure would result in significant material loss of unprotected ram facing organic matrix composites. Several protective coatings for composites were flown on LDEF including anodized aluminum, vacuum deposited coatings, a variety of thermal control coatings, metalized Teflon, and leafing aluminum. Results from the testing and analysis of the coated and uncoated composite specimens flown on LDEF's leading and trailing edges provide the baseline for determining the effectiveness of protectively coated composites in LEO. In addition to LDEF results, results from shuttle flight experiments and ground based testing will be discussed.

Validating the Proton Prediction System (PPS)

DTIC Science & Technology

2006-12-01

hazards for astro - proton fluence model (Feynman et al., 2002) fits nauts on the missions to the Moon and Mars observed SEP event fluences of E>10MeV...events limited the useful PPS test cases to 78 of the J(E>10MeV) = 347 x ( Fx )0.941, (3) 101 solar flares. Although they can be serious radiation...hazards (Reames, 1999), PPS does not where Fx is the GOES 1-8 A X-ray flare half-power predict the E> 10MeV peaks often seen during the fluence in J cm -2

Durable hydrophobic coating composition for metallic surfaces and method for the preparation of the composition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jiong

A durable hydrophobic coating composition containing fluorinated silanes for metallic surfaces, such as stainless steel surfaces. The composition includes at least one fluorine-containing silane compound, at least one phosphorus-containing silane compound, and at least one hydrolysable compound. This coating is suitable for condenser tubes, among other applications, to promote dropwise condensation.

Effects of Co contents on the microstructures and properties of the electrodeposited NiCo–Zr composite coatings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Fei; Jiang, Chuanhai, E-mail: chuanhaijiang1963@163.com; Zhao, Yuantao

2015-05-15

Highlights: • The novel NiCo–Zr coatings were prepared by electro-deposition. • Surface morphology, crystal structure, grain size and microstrain were examined. • Texture, residual stress and corrosion resistance were investigated. • Addition of Co increased the hardness and corrosion resistance of the coatings. - Abstract: In this study, the NiCo–Zr composite coatings were prepared from the electrolytes with different Co{sup 2+} concentrations by electrodeposition method. The effects of Co contents on the crystal structure, surface morphology, grain size, microstrain and residual stress were examined by X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), Energy dispersive X-ray spectroscopy (EDX) andmore » atomic force microscope (AFM). The corrosion resistance of the composite coatings was also examined by the potentiodynamic polarization and electrochemical impedance (EIS) measurements. The results revealed that the crystal structures of the coatings were dependent on the Co contents and addition of Co content of 58 wt% resulted in the formation of hexagonal (hcp) Co. The increasing Co contents in the NiCo–Zr composite coatings resulted in the smoother and more compact surface, decreased the grain size and increased the microstrain. The micro-hardness and residual stress also increased with increasing Co contents. The addition of Co increased the corrosion resistance of the NiCo–Zr composite coatings compared with the Ni–Zr coating while the corrosion resistance of the NiCo–Zr composite coatings decreased as the Co contents increased.« less

Coatings of needle/stripe-like fluoridated hydroxyapatite on H2O2-treated carbon/carbon composites prepared by induction heating and hydrothermal methods

NASA Astrophysics Data System (ADS)

Xiong, Xin-Bo; Huang, Jian-Feng; Zeng, Xie-Rong; Liang, Ping; Zou, Ji-Zhao

2012-06-01

A hydroxyapatite (HA) coating was achieved on H2O2-treated carbon/carbon (C/C) composite through hydrothermally treating and induction heating deposited CaHPO4 coating in an ammonia solution under ultrasonic water bath. Then, this HA coating was placed in a NH4F solution and hydrothermally treated again to fabricate fluorinated hydroxyapatite (FHA) coatings for 24 h at 353, 373, 393 and 413 K, respectively. The structure, morphology and chemical composition of the HA and FHA coatings were characterized by SEM, XRD, EDS and FTIR, and the adhesiveness and chemical stability of these FHA coatings were examined by a scratch test and an immersion test, respectively. The results showed that the as-prepared FHA coatings contained needle-like or stripe-like crystals, different from those of the HA coating. As the fluoridation temperature rose, the adhesiveness of the FHA coating first increased from 34.8 to 40.9 N at a temperature between 353 and 393 K, and then decreased to 24.2 N at 413 K, while the dissolution rate of the FHA coating decreased steadily. The reasons for the property variation of the FHA coatings were proposed by analyzing the morphology, composition and structure of the coatings.

Thermal Performance Study of Composite Phase Change Material with Polyacrylicand Conformal Coating.

PubMed

Kee, Shin Yiing; Munusamy, Yamuna; Ong, Kok Seng; Cornelis Metselaar, Hendrik Simon; Chee, Swee Yong; Lai, Koon Chun

2017-07-28

The composite PCM was prepared by blending polymethyl methacrylate (PMMA) and myristic acid (MA) in different weight percentages. The MA and PMMA were selected as PCM and supporting material, respectively. As liquid MA may leak out during the phase transition, this study proposes the use of two coatings, namely a polyacrylic coating and a conformal coating to overcome the leakage problem. Both coatings were studied in terms of the leakage test, chemical compatibility, thermal stability, morphology, and reliability. No leakage was found in the PCMs with coatings compared to those without under the same proportions of MA/PMMA, thus justifying the use of coatings in the present study. The chemically compatibility was confirmed by FTIR spectra: the functional groups of PCMs were in accordance with those of coatings. DSC showed that the coatings did not significantly change the melting and freezing temperatures, however, they improved the thermal stability of composite PCMs as seen in TGA analysis. Furthermore, the composite PCMs demonstrated good thermal reliability after 1000 times thermal cycling. The latent heat of melting reduced by only 0.16% and 1.02% for the PCMs coated with conformal coating and polyacrylic coating, respectively. Therefore, the proposed coatings can be considered in preparing fatty acid/PMMA blends attributed to the good stability, compatibility and leakage prevention.

Electrophoretic co-deposition of polyvinyl alcohol (PVA) reinforced alginate-Bioglass® composite coating on stainless steel: mechanical properties and in-vitro bioactivity assessment.

PubMed

Chen, Qiang; Cabanas-Polo, Sandra; Goudouri, Ourania-Menti; Boccaccini, Aldo R

2014-07-01

PVA reinforced alginate-bioactive glass (BG) composite coatings were produced on stainless steel by a single step electrophoretic deposition (EPD) process. The present paper discusses the co-deposition mechanism of the three components and presents a summary of the relevant properties of the composite coatings deposited from suspensions with different PVA concentrations. Homogeneous composite coatings with compact microstructure and increased thickness, i.e. as high as 10 μm, were observed by scanning electron microscopy (SEM). The surface roughness of coatings with different PVA contents was slightly increased, while a significant increase of water contact angles due to PVA addition was detected and discussed. Improved adhesion strength of coatings containing different amounts of PVA was quantitatively and qualitatively confirmed by pull-off adhesion and cycled bending tests, respectively. In-vitro bioactivity tests were performed in simulated body fluid (SBF) for 0.5, 1, 2, 4, 7, and 14 days, respectively. The decomposition rate of the coatings was reduced with PVA content, and rapid hydroxyapatite forming ability of the composite coatings in SBF was confirmed by FTIR and XRD analyses. According to the results of this study, composite alginate-Bioglass® bioactive coatings combined with PVA are proposed as promising candidates for dental and orthopedic applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Plasma-panel based detectors

NASA Astrophysics Data System (ADS)

Friedman, Peter

2017-09-01

The plasma panel sensor (PPS) is a novel micropattern gas detector inspired by plasma display panels (PDPs), the core component of plasma-TVs. A PDP comprises millions of discrete cells per square meter, each of which, when provided with a signal pulse, can initiate and sustain a plasma discharge. Configured as a detector, a pixel or cell is biased to discharge when a free-electron is generated in the gas. The PPS consists of an array of small plasma discharge pixels, and can be configured to have either an ``open-cell'' or ``closed-cell'' structure, operating with high gain in the Geiger region. We describe both configurations and their application to particle physics. The open-cell PPS lends itself to ultra-low-mass, ultrathin structures, whereas the closed-cell microhexcavity PPS is capable of higher performance. For the ultrathin-PPS, we are fabricating 3-inch devices based on two types of extremely thin, inorganic, transparent, substrate materials: one being 8-10 µm thick, and the other 25-27 µm thick. These gas-filled ultrathin devices are designed to operate in a beam-line vacuum environment, yet must be hermetically-sealed and gas-filled in an ambient environment at atmospheric pressure. We have successfully fabricated high resolution, submillimeter pixel electrodes on both types of ultrathin substrates. We will also report on the fabrication, staging and operation of the first microhexcavity detectors (µH-PPS). The first µH-PPS prototype devices have a 16 by 16 matrix of closed packed hexagon pixels, each having a 2 mm width. Initial tests of these detectors, conducted with Ne based gases at atmospheric pressure, indicate that each pixel responds independent of its neighboring cells, producing volt level pulse amplitudes in response to ionizing radiation. Results will include the hit rate response to a radioactive beta source, cosmic ray muons, the background from spontaneous discharge, pixel isolation and uniformity, and efficiency measurements. This work was funded in part by a DOE Office of Nuclear Physics SBIR Phase-II Grant.

Measuring Responsible Gambling amongst Players: Development of the Positive Play Scale

PubMed Central

Wood, Richard T. A.; Wohl, Michael J. A.; Tabri, Nassim; Philander, Kahlil

2017-01-01

The modern gambling industry has, by-in-large, assumed a duty of care to minimize the risks associated with gambling, which has manifested in responsible gambling (RG) programming (e.g., educating players about the odds of success). The current study fills a void in gambling operators, regulators, and researchers ability to measure RG beliefs and behavior in their player-base, with the development and validation of the Positive Play Scale (PPS). In Study 1, we reviewed the literature and consulted 30 players as well as 10 RG experts to help generate a definition of RG beliefs and behavior that helped guide item generation. In Study 2, regular players (N = 1,551) of a Canadian provincial gambling operator completed a positive play survey. Four components from a principal components analysis (PCA) were extracted: Honesty and Control, Pre-commitment, Personal Responsibility, and Gambling Literacy. The PPS subscales were either not associated with gambling frequency or had small-to-moderate negative relationships with frequency of play for games most often associated with disordered gambling (e.g., electronic games). In Study 3 (N = 413), the factor structure of the PPS was confirmed and refined in a new sample of players. Moreover, a 1-month follow-up session demonstrated that the PPS has high test-retest reliability. The PPS is the first validated scale that reliably assesses the extent to which a consumer base has positive beliefs about gambling and gambles in a positive manner. The PPS can be used by the gambling industry to objectively assess the efficacy of their RG strategy, pinpoint specific areas for future focus, as well as examine the utility of new RG initiatives that aim to promote healthy patterns of gambling consumption. Furthermore, by examining the PPS scores for different player segments (e.g., sex, age, games played) it becomes possible to tailor RG strategy to the needs of specific players. In this way, RG strategy can be optimized by focusing resources where they will be most effective. PMID:28280472

Helping members of a community-based health insurance scheme access quality inpatient care through development of a preferred provider system in rural Gujarat

PubMed Central

RANSON, M. KENT; SINHA, TARA; GANDHI, FENIL; JAYSWAL, RUPAL; MILLS, ANNE J.

2007-01-01

We describe and analyse the experience of piloting a preferred provider system (PPS) for rural members of Vimo SEWA, a fixed-indemnity, community-based health insurance (CBHI) scheme run by the Self-Employed Women’s Association (SEWA). The objectives of the PPS were (i) to facilitate access to hospitalization by providing financial benefits at the time of service utilization; (ii) to shift the burden of compiling a claim away from members and towards Vimo SEWA staff; and (iii) to direct members to inpatient facilities of acceptable quality. The PPS was launched between August and October 2004, in 8 subdistricts covering 15 000 insured. The impact of the scheme was analysed using data from a household survey of claimants and qualitative data from in-depth interviews and focus group discussions. The PPS appears to have been successful in terms of two of the three primary objectives—it has transferred much of the burden of compiling a health insurance claim onto Vimo SEWA staff, and it has directed members to inpatient facilities with acceptable levels of technical quality (defined in terms of structural indicators). However, even under the PPS, user fees pose a financial barrier, as the insured have to mobilize funds to cover the costs of medicines, supplies, registration fee, etc. before receipt of cash payment from Vimo SEWA. Other barriers to the success of the PPS were the geographic inaccessibility of some of the selected hospitals, lack of awareness about the PPS among members and a variety of administrative problems. This pilot project provides useful lessons relating to strategic purchasing by CBHI schemes and, more broadly, managed care in India. In particular, the pragmatic approach taken to assessing hospitals and identifying preferred providers is likely to be useful elsewhere. PMID:17203684

A magnetic isolation and pointing system for the astrometric telescope facility

NASA Technical Reports Server (NTRS)

Smith, Marcie; Hibble, William; Wolke, Patrick J.

1993-01-01

The astrometric telescope facility (ATF), a 20-meter telescope designed for long-term detection and observation of planetary systems outside of the solar system, is scheduled to be a major user of the Space Station's payload pointing system (PPS) capabilities. However, because the ATF has such a stringent pointing stability specification (as low as 0.01 arcsec error over the frequency range from 5 to 200 hertz) and requires +/- 180-degree roll rotation around the telescope's line of sight, the ATF's utilization of the PPS requires the addition of a mechanism or mechanisms to enhance the basic PPS capabilities. The results of a study conducted to investigate the ATF pointing performance achievable by the addition of a magnetic isolation and pointing (MIPS) system between the PPS upper gimbal and the ATF, and separately, by the addition of a passive isolation system between the Space Station and the PPS base are presented. In addition, the study produced requirements on magnetic force and gap motion as a function of the level of Space Station disturbance. These results were used to support the definition of a candidate MIPS. Pointing performance results from the study indicate that a MIPS can meet the ATF pointing requirements in the presence of a PPS base transitional acceleration of up to 0.018g, with reasonable restrictions placed on the isolation and pointing bandwidths. By contrast, the passive base isolator system must have an unrealistically low isolation bandwidth on all axes (less than 0.1 hertz) to meet ATF pointing requirements. The candidate MIPS is based on an assumed base translational disturbance of 0.01g. The system fits within the available annular region between the PPS and ATF while meeting power and weight limitations and providing the required payload roll motion. Payload data and power services are provided by noncontacting transfer devices.

Impact of road traffic “penalty points” on high energy pelvic trauma

PubMed Central

Ellanti, Prasad; Davarinos, Nikos; Morris, Seamus; McElwain, John Paul

2013-01-01

Background: The penalty points system (PPS) was introduced in 2002 in an attempt to reduce the increasing rate of road traffic accident (RTA) related fatalities and serious injuries. Points are awarded based on the severity of the offence and are cumulative. A total of 12 points results in the disqualification from driving. Objective: A few studies have looked at the immediate or short term impact of PPS on trauma services or specific injuries such as spine trauma in Ireland. Little data is available on the long term effect of the PPS. The aim of this study is to see if the PPS system has had an influence on the number of pelvic injuries referred to our unit for surgical intervention and if this influence is sustained in the longer term. Materials and Methods: A retrospective review of all pelvic and acetabular injuries admitted to our unit from 1999 to 2008 was undertaken. The mechanism of injury, the site and patient demographics were noted. Results: A total of 467 patients were identified over the ten year period. 454 patients were included in the study. There was a significant male preponderance of 76%. Mean age was 36.5 years (range 16 to 83). RTA's were the cause in 74% (n = 335) of the cases. The annual work load remained similar over the years. There has been a reduction in the number of RTA related pelvic injuries. There have been notable drops in the number of these cases corresponding to the introduction of the PPS and its subsequent expansion. The number of pelvic injuries due to falls continues to rise. Conslusion: The introduction of the PPS and its subsequent expansion has had a positive influence on the number of RTA related pelvic trauma. Continued surveillance and enforcement of the PPS is important for a sustained benefit from it in the long term. PMID:23723619

Bioactive glass-chitosan composite coatings on PEEK: Effects of surface wettability and roughness on the interfacial fracture resistance and in vitro cell response

NASA Astrophysics Data System (ADS)

Hong, Wei; Guo, Fangwei; Chen, Jianwei; Wang, Xin; Zhao, Xiaofeng; Xiao, Ping

2018-05-01

To improve the osteointegration of polyetheretherketone (PEEK) spinal fusions, the 45S5 bioactive glass® (BG)-chitosan (CH) composite was used to coat the PEEK by a dip-coating method at room temperature. A robust bonding between the BG-CH composite coating and the PEEK was achieved by a combined surface treatment of sand blasting and acid etching. The effects of surface wettability and surface roughness on the adhesion of the BG-CH composite coating were characterized by fracture resistance (Gc), respectively, measured by four-point bending tests. Compared with the surface polar energy (wettability), the surface roughness (>3 μm) played a more important role for the increase in Gc values by means of crack shielding effect under the mixed mode stress. The maximum adhesion strength (σ) of the coatings on the modified PEEK measured by the tensile pull-off test was about 5.73 MPa. The in vitro biocompatibilities of PEEK, including cell adhesion, cell proliferation, differentiation, and bioactivity in the stimulated body fluid (SBF), were enhanced by the presence of BG-CH composite coatings, which also suggested that this composite coating method could provide an effective solution for the weak PEEK-bone integration.

Application of carbide cutting tools with nano-structured multilayer composite coatings for turning austenitic steels, type 16Cr-10NI

NASA Astrophysics Data System (ADS)

Vereschaka, Alexey; Migranov, Mars; Oganyan, Gaik; Sotova, Catherine S.; Batako, Andre

2018-03-01

This paper addresses the challenges of increasing the efficiency of the machining of austenitic stainless steels AISI 321 and S31600 by application of cutting tools with multilayer composite nano-structured coatings. The main mechanical properties and internal structures of the coatings under study (hardness, adhesion strength in the "coating-substrate" system) were investigated, and their chemical compositions were analyzed. The conducted research of tool life and nature of wear of carbide tools with the investigated coatings during turning of the above mentioned steels showed that the application of those coatings increases the tool life by up to 2.5 times. In addition, the use of a cutting tool with coatings allows machining at higher cutting speeds. It was also found that the use of a tool with multilayer composite nano-structured coating (Zr,Nb)N-(Zr,Al,Nb)N ensures better results compared with not only monolithic coating TiN, but also with nano-structured coatings Ti-TiN-(Ti,Al)N and (Zr,Nb)N-(Cr,Zr,Nb,Al)N. The mechanism of failure of the coatings under study was also investigated.

Medicare's prospective payment system: A critical appraisal

PubMed Central

Coulam, Robert F.; Gaumer, Gary L.

1992-01-01

Implementation of the Medicare prospective payment system (PPS) for hospital payment has produced major changes in the hospital industry and in the way hospital services are used by physicians and their patients. The substantial published literature that examines these changes is reviewed in this article. This literature suggests that most of the intended effects of PPS on costs and intensity of care have been realized. But the literature fails to answer fundamental questions about the effectiveness and equity of administered pricing as a policy tool for cost containment. The literature offers some hope that the worst fears about the effects of PPS on quality of care and the health of the hospital industry have not materialized. But because of data lags, the studies done to date seem to tell us more about the effects of the early, more generous period of PPS than about the opportunity costs of reducing hospital cost inflation. PMID:25372306

The fairness of the PPS reimbursement methodology.

PubMed Central

Gianfrancesco, F D

1990-01-01

In FY 1984 the Medicare program implemented a new method of reimbursing hospitals for inpatient services, the Prospective Payment System (PPS). Under this system, hospitals are paid a predetermined amount per Medicare discharge, which varies according to certain patient and hospital characteristics. This article investigates the presence of systematic biases and other potential imperfections in the PPS reimbursement methodology as revealed by its effects on Medicare operating ratios. The study covers the first three years of the PPS (approximately 1984-1986) and is based on hospital data from the Medicare cost reports and other related sources. Regression techniques were applied to these data to determine how Medicare operating ratios were affected by specific aspects of the reimbursement methodology. Several possible imbalances were detected. The potential undercompensation relating to these can be harmful to certain classes of hospitals and to the Medicare populations that they serve. PMID:2109738

Amputation and prosthesis implantation shape body and peripersonal space representations

PubMed Central

Canzoneri, Elisa; Marzolla, Marilena; Amoresano, Amedeo; Verni, Gennaro; Serino, Andrea

2013-01-01

Little is known about whether and how multimodal representations of the body (BRs) and of the space around the body (Peripersonal Space, PPS) adapt to amputation and prosthesis implantation. In order to investigate this issue, we tested BR in a group of upper limb amputees by means of a tactile distance perception task and PPS by means of an audio-tactile interaction task. Subjects performed the tasks with stimulation either on the healthy limb or the stump of the amputated limb, while wearing or not wearing their prosthesis. When patients performed the tasks on the amputated limb, without the prosthesis, the perception of arm length shrank, with a concurrent shift of PPS boundaries towards the stump. Conversely, wearing the prosthesis increased the perceived length of the stump and extended the PPS boundaries so as to include the prosthetic hand, such that the prosthesis partially replaced the missing limb. PMID:24088746

Coatings for graphite fibers

NASA Technical Reports Server (NTRS)

Galasso, F. S.; Scola, D. A.; Veltri, R. D.

1980-01-01

Graphite fibers released from composites during burning or an explosion caused shorting of electrical and electronic equipment. Silicon carbide, silica, silicon nitride and boron nitride were coated on graphite fibers to increase their electrical resistances. Resistances as high as three orders of magnitude higher than uncoated fiber were attained without any significant degradation of the substrate fiber. An organo-silicone approach to produce coated fibers with high electrical resistance was also used. Celion 6000 graphite fibers were coated with an organo-silicone compound, followed by hydrolysis and pyrolysis of the coating to a silica-like material. The shear and flexural strengths of composites made from high electrically resistant fibers were considerably lower than the shear and flexural strengths of composites made from the lower electrically resistant fibers. The lower shear strengths of the composites indicated that the coatings on these fibers were weaker than the coating on the fibers which were pyrolyzed at higher temperature.

Preparation and characterization of Ni-P/Ni3.1B composite alloy coatings

NASA Astrophysics Data System (ADS)

Wang, Yurong; He, Jiawei; Wang, Wenchang; Shi, Jianhua; Mitsuzaki, Naotoshi; Chen, Zhidong

2014-02-01

The preparation of Ni-P/Ni3.1B composite alloy coating on the surface of copper was achieved by co-deposition of Ni3.1B nanoparticles with Ni-P coating during electroless plating. Ni-P-B alloy coating was obtained by heat-treating the as-plated Ni-P/Ni3.1B composite coating. The effect of the concentration of sodium alginate, borax, thiourea, Ni3.1B, temperature, and pH value on the deposition rate and B content were investigated and determined to be: 30 g L-1, 10 g L-1, 2 mg L-1, 20 mg L-1, 70 °C and 9.0 , respectively. Sodium alginate and thiourea were played as surfactant for coating Ni3.1B nanoparticles and stabilizer for the plating bath, respectively. Ni-P/Ni3.1B composite coating had good performance such as corrosion resistance and solderability.

Cationic electrodepositable coating composition comprising lignin

DOEpatents

Fenn, David; Bowman, Mark P; Zawacky, Steven R; Van Buskirk, Ellor J; Kamarchik, Peter

2013-07-30

A cationic electrodepositable coating composition is disclosed. The present invention in directed to a cationic electrodepositable coating composition comprising a lignin-containing cationic salt resin, that comprises (A) the reaction product of: lignin, an amine, and a carbonyl compound; (B) the reaction product of lignin, epichlorohydrin, and an amine; or (C) combinations thereof.

In-Situ Synthetic TiB2 Particulate Reinforced Metal Matrix Composite Coating on AA2024 Aluminum Alloy by Laser Cladding Technology

NASA Astrophysics Data System (ADS)

Xu, Jiang; Kan, Yide; Liu, Wenjin

In order to improve the wear resistance of aluminum alloy, in-situ synthesized TiB2 and Ti3B4 peritectic composite particulate reinforced metal matrix composite, formed on a 2024 aluminum alloy by laser cladding with a powder mixture of Fe-coated Boron, Ti and Al, was successfully achieved using 3-KW CW CO2 laser. The chemical composition, microstructure and phase structure of the composite clad coating were analyzed by energy dispersive X-ray spectroscopy (EDX), SEM, AFM and XRD. The typical microstructure of the composite coating is composed of TiB2, Ti3B4, Al3Ti, Al3Fe and α-Al. The surface hardness of cladding coating increases with the amount of added Fe-coated B and Ti powder which determines the amount of TiB2 and Ti3B4 peritectic composite particulate. The nanohardness and the elastic modulus at the interface of the TiB2 and Ti3B4 peritectic composite particulate/matrix were investigated using the nanoindentation technique. The results showed that the nanohardness and the reduced elastic modulus from the peritectic composite particulate to the matrix is a gradient distribution.

Antibacterial Property of Cold-Sprayed HA-Ag/PEEK Coating

NASA Astrophysics Data System (ADS)

Sanpo, Noppakun; Tan, Meng Lu; Cheang, Philip; Khor, K. A.

2009-03-01

The antibacterial behavior of HA-Ag (silver-doped hydroxyapatite) nanopowder and their composite coatings were investigated against Escherichia coli (DH5α). HA-Ag nanopowder and PEEK (poly-ether-ether-ketone)-based HA-Ag composite powders were synthesized using in-house powder processing techniques. Bacteria culture assay of HA-Ag nanopowder and their composite powders displayed excellent bacteriostatic activity against E. coli. The antibacterial activity increased with increasing concentration of HA-Ag nanoparticle in these composite powders. These nanocomposite powders were subsequently used as feedstock to generate antibacterial coatings via cold spray technology. The ratios of HA-Ag to PEEK in their composite powders were 80:20, 60:40, 40:60, and 20:80 (wt.%). Microstructural characterization and phase analysis of feedstock powders and as-deposited coatings were carried out using FESEM/EDX and XRD. Antibacterial nanocomposite HA-Ag/PEEK coatings were successfully deposited using cold spraying parameters of 11-12 bars at preheated air temperature between 150 and 160 °C. These as-sprayed coatings of HA-Ag/PEEK composite powders comprising varying HA-Ag and PEEK ratios retained their inherent antibacterial property as verified from bacterial assay. The results indicated that the antibacterial activity increased with increasing HA-Ag nanopowder concentration in the composite powder feedstock and cold-sprayed coating.

FeCoNi coated glass fibers in composite sheets for electromagnetic absorption and shielding behaviors

NASA Astrophysics Data System (ADS)

Lee, Joonsik; Jung, Byung Mun; Lee, Sang Bok; Lee, Sang Kwan; Kim, Ki Hyeon

2017-09-01

To evaluate the electromagnetic (EM) absorption and shield of magnetic composite sheet, we prepared the FeCoNi coated glass fibers filled in composite sheet. The FeCoNi was coated by electroless plating on glass fiber as a filler. The coated FeCoNi found that consist of mixtures of bcc and fcc phase. The magnetization and coercivity of coated FeCoNi are about 110 emu/g and 57 Oe, respectively. The permittivity and permeability of the FeCoNi composite sheet were about 21 and 1, respectively. Power absorption increased 95% with the increment of frequency up to 10 GHz. Inter-decoupling of this composite sheet showed maximum 30 dB at around 5.3 GHz, which is comparable to that of a conductive Cu foil. Shielding effectiveness (SE) was measured by using rectangular waveguide method. SE of composite obtained about 37 dB at X-band frequency region.

Potential Fungus surface resistance of the silica/acrylic coated leaves waste composite

NASA Astrophysics Data System (ADS)

Masturi; Jannah, WN; Maulana, RM; Darsono, T.; Sunarno; Rustad, S.

2018-04-01

The composite coated by some materials coaters have been made. This coating was done to isolate the fungus possibly growing on the composite. The composite was made from a mixture of teak leaves waste and polyurethane polymer using a simple mixing method; then the mixture was pressed at a pressure of 3 metric-tons for 15 minutes. The composite produced then was coated with acrylic only and acrylic-silica using spray method. The coated samples then were characterized using scanning electron microscopy (SEM) to determine the surface pores. Further, it was obtained the average surface pore size of acrylic coater is 1.24 µm, while the acrylic-silica pore forms an oval shape with a length and a width of 0.75 µm and 0.38 µm, respectively. In comparison with the fungus size of 2-7 µm, it can be concluded that the composite is proper as home appliance application.

Application of C/C composites to the combustion chamber of rocket engines. Part 1: Heating tests of C/C composites with high temperature combustion gases

NASA Astrophysics Data System (ADS)

Tadano, Makoto; Sato, Masahiro; Kuroda, Yukio; Kusaka, Kazuo; Ueda, Shuichi; Suemitsu, Takeshi; Hasegawa, Satoshi; Kude, Yukinori

1995-04-01

Carbon fiber reinforced carbon composite (C/C composite) has various superior properties, such as high specific strength, specific modulus, and fracture strength at high temperatures of more than 1800 K. Therefore, C/C composite is expected to be useful for many structural applications, such as combustion chambers of rocket engines and nose-cones of space-planes, but C/C composite lacks oxidation resistivity in high temperature environments. To meet the lifespan requirement for thermal barrier coatings, a ceramic coating has been employed in the hot-gas side wall. However, the main drawback to the use of C/C composite is the tendency for delamination to occur between the coating layer on the hot-gas side and the base materials on the cooling side during repeated thermal heating loads. To improve the thermal properties of the thermal barrier coating, five different types of 30-mm diameter C/C composite specimens constructed with functionally gradient materials (FGM's) and a modified matrix coating layer were fabricated. In this test, these specimens were exposed to the combustion gases of the rocket engine using nitrogen tetroxide (NTO) / monomethyl hydrazine (MMH) to evaluate the properties of thermal and erosive resistance on the thermal barrier coating after the heating test. It was observed that modified matrix and coating with FGM's are effective in improving the thermal properties of C/C composite.

In situ electrodeposition of CoP nanoparticles on carbon nanomaterial doped polyphenylene sulfide flexible electrode for electrochemical hydrogen evolution

NASA Astrophysics Data System (ADS)

Wang, Tingxia; Jiang, Yimin; Zhou, Yaxin; Du, Yongling; Wang, Chunming

2018-06-01

Active and durable electrocatalyst for hydrogen evolution reaction (HER) is pivotal to generate molecular hydrogen more energy-efficient, but directly grafting electrocatalyst on electrode material by a single-step method without compromising the catalytic activity and stability remains a challenge. Herein, an intriguing electrode, reduced graphene oxide modified carbon nanotube/reduced graphene oxide/polyphenylene sulfide (RGO-CNT/RGO/PPS) film, is used to replace conventional electrodes. In situ electrodeposition is proposed to fabricate CoP on the RGO-CNT/RGO/PPS (CoP-RGO-CNT/RGO/PPS) electrode and achieves a favorably electrical contact between CoP nanoparticles and RGO-CNT/RGO/PPS electrode due to without any polymer binder. Additionally, the coupling of different electrodeposition stages with scanning electron microscope (SEM) can investigate the nanostructure evolution of CoP nanoparticles, which gives valuable insights into the optimized electrodeposition cycles. The rational integration of RGO onto CNT/RGO/PPS film is an effective approach for enhancing its intrinsic electrical conductivity and favoring the formation of a high density of dispersive CoP nanoparticles. The CoP-RGO-CNT/RGO/PPS film has shown outstanding HER electrocatalytic behaviors performed a current density of 10 mA cm-2 at a relatively low overpotential of 160 mV with a Tafel slope of 60 mV dec-1 in acidic medium, which can be mainly attributed to the synergistic effect between optimized morphology and accelerated kinetics. Additionally, this film electrocatalyst exhibits a good HER activity and stability under both neutral and basic conditions.

Interaction of Selected Phenylpropenes with Dipalmitoylphosphatidylcholine Membrane and Their Relevance to Antibacterial Activity.

PubMed

Gharib, Riham; Najjar, Amal; Auezova, Lizette; Charcosset, Catherine; Greige-Gerges, Hélène

2017-06-01

The effect of structurally closely related phenylpropenes (PPs), estragole, anethole, eugenol, and isoeugenol, on the fluidity of dipalmitoyl phosphatidyl choline (DPPC) liposome membrane was investigated by DSC, Raman, and fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH). Liposomes were prepared by thin-film hydration method at various DPPC:PP molar ratios. The DPH anisotropy measurements of blank and PP-loaded liposomes were performed at 28, 41, and 50 °C, which correspond, respectively, to gel phase, main transition temperature of DPPC, and liquid phase. The Raman images showed the formation of nano- and micrometric spherical multi-lamellar vesicles. All studied PPs exhibited a membrane fluidizing effect which was reinforced by the presence of phenolic hydroxyl group in eugenol and isoeugenol. The PPs interacted with the choline head group and the alkyl chains of DPPC membrane, wherein isoeugenol and anethole possessing the same C7-C8 position of the double bond in the propenyl side chain, incorporated deeply in the bilayer. Additionally, the PPs were analyzed for antibacterial activity against E. coli by macrobroth dilution method. Anethole and estragole were more efficient in inhibiting the bacterial growth than eugenol and isoeugenol. We conclude that the fluidizing effect of PPs on the membrane is a common mechanism that is not related to the hydrophobicity of the PP molecule. Besides, other target sites may be involved in PP antibacterial activity against Gram-negative bacteria. The greater hydrophobicity of these PPs may contribute to their penetrability through the outer bacterial membrane.

Charting a path forward: policy analysis of China's evolved DRG-based hospital payment system.

PubMed

Liu, Rui; Shi, Jianwei; Yang, Beilei; Jin, Chunlin; Sun, Pengfei; Wu, Lingfang; Yu, Dehua; Xiong, Linping; Wang, Zhaoxin

2017-09-01

At present, the diagnosis-related groups-based prospective payment system (DRG-PPS) that has been implemented in China is merely a prototype called the simplified DRG-PPS, which is known as the 'ceiling price for a single disease'. Given that studies on the effects of a simplified DRG-PPS in China have usually been controversial, we aim to synthesize evidence examining whether DRGs can reduce medical costs and length of stay (LOS) in China. Data were searched from both Chinese [Wan Fang and China National Knowledge Infrastructure Database (CNKI)] and international databases (Web of Science and PubMed), as well as the official websites of Chinese health departments in the 2004-2016 period. Only studies with a design that included both experimental (with DRG-PPS implementation) and control groups (without DRG-PPS implementation) were included in the review. The studies were based on inpatient samples from public hospitals distributed in 12 provinces of mainland China. Among them, 80.95% (17/21) revealed that hospitalization costs could be reduced significantly, and 50.00% (8/16) indicated that length of stay could be decreased significantly. In addition, the government reports showed the enormous differences in pricing standards and LOS in various provinces, even for the same disease. We conclude that the simplified DRGs are useful in controlling hospitalization costs, but they fail to reduce LOS. Much work remains to be done in China to improve the simplified DRG-PPS. © The Author 2017. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.

New entrants' practice patterns in Medicare home health care after the prospective payment system revision in 2008.

PubMed

Kim, Hyunjee; Jung, Jeah Kyoungrae

2015-09-01

Medicare home health care spending increased under the prospective payment system (PPS) that was introduced specifically to control the rising spending. To explain this unexpected spending rise, we focused on new home health agencies that entered the market under the PPS. The high profit margins under the PPS attracted many new agencies to the market partially due to home health care's unique feature of low entry costs. We examined whether new entrants were more likely to adopt the practice patterns leading to higher profit margins than incumbent agencies that had been operating in the market before the PPS. Using 2008 to 2010 Medicare Home Health Claims and Provider of Services File, we estimated regressions of agencies' practice patterns controlling for agency and patient characteristics. We found that new entrants were more likely than incumbents to adopt practice patterns leading to high profit margins. They were more likely to target the 14th and 20th therapy visit where marginal revenue is relatively greater than that of other number of visits. Under the payment system that compensates extra therapy visits but not for other types of visits, entrants were also more likely to provide therapy visits, but less likely to provide medical social service visits. Given the high entry rates of agencies under the PPS, distinct practice patterns among entrants explain the drastic home health spending increase under the PPS. Heterogeneity in agencies' practice patterns also suggests an opportunity to improve efficiency in the Medicare home health care market. Copyright © 2015 Elsevier Inc. All rights reserved.

Program for plasma-sprayed self-lubricating coatings

NASA Technical Reports Server (NTRS)

Walther, G. C.

1979-01-01

A method for preparing composite powders of the three coating components was developed and a procedure that can be used in applying uniform coatings of the composite powders was demonstrated. Composite powders were prepared by adjusting particle sizes of the components and employing a small amount of monoaluminum phosphate as an inorganic binder. Quantitative microscopy (image analysis) was found to be a convenient method of characterizing the composition of the multiphase plasma-sprayed coatings. Area percentages and distribution of the components were readily obtained by this method. The adhesive strength of the coating to a nickel-chromium alloy substrate was increased by about 40 percent by a heat treatment of 20 hours at 650 C.

Composite polymer-containing coatings on Mg alloys perspective for industry and implant surgery

NASA Astrophysics Data System (ADS)

Gnedenkov, S. V.; Sinebryukhov, S. L.; Mashtalyar, D. V.; Imshinetskiy, I. M.; Gnedenkov, A. S.; Minaev, A. N.

2017-09-01

In order to improve the corrosion resistance of magnesium alloys the ways of composite protective coating formation were developed by means of plasma electrolytic oxidation (PEO) as well as electrophoretic deposition methods. Electrochemical, corrosion, tribological, and morphological properties of the MAS magnesium alloy composite coatings were studied. The composite polymer-containing coating decrease the corrosion current density values by three orders of magnitude (Ic = 2.0 . 10-10 A/cm2), in comparison with the base PEO-layer. These polymer-containing layers enable one to expand the practical usage area of Mg alloys. The application of such coatings provides the increasing the bioactivity and regulate the corrosion rate of resorbable magnesium implants.

Internal coating of air cooled gas turbine blades

NASA Technical Reports Server (NTRS)

Ahuja, P. L.

1979-01-01

Six coating systems were evaluated for internal coating of decent stage (DS) eutectic high pressure turbine blades. Sequential deposition of electroless Ni by the hydrazine process, slurry Cr, and slurry Al, followed by heat treatment provided the coating composition and thickness for internal coating of DS eutectic turbine blades. Both NiCr and NiCrAl coating compositions were evaluated for strain capability and ductile to brittle transition temperature.

Comparison study of biomimetic strontium-doped calcium phosphate coatings by electrochemical deposition and air plasma spray: morphology, composition and bioactive performance.

PubMed

Li, Ling; Lu, Xia; Meng, Yizhi; Weyant, Christopher M

2012-10-01

In this study, strontium-doped calcium phosphate coatings were deposited by electrochemical deposition and plasma spray under different process parameters to achieve various coating morphologies. The coating composition was investigated by energy dispersive X-ray spectroscopy and X-ray diffraction. The surface morphologies of the coatings were studied through scanning electron microscopy while the cytocompatibility and bioactivity of the strontium-doped calcium phosphate coatings were evaluated using bone cell culture using MC3T3-E1 osteoblast-like cells. The addition of strontium leads to enhanced proliferation suggesting the possible benefits of strontium incorporation in calcium phosphate coatings. The morphology and composition of deposited coatings showed a strong influence on the growth of cells.

Microstructure and properties of Cu-Sn-Zn-TiO 2 nano-composite coatings on mild steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Weidong; Cao, Di; Jin, Yunxue

Cu-Sn-Zn coatings have been widely used in industry for their unique properties, such as good conductivity, high corrosion resistance and excellent solderability. To further improve the mechanical performance of Cu-Sn-Zn coatings, powder-enhanced method was applied and Cu-Sn-Zn-TiO 2 nano-composite coatings with different TiO 2 concentration were fabricated. The microstructure of Cu-Sn-Zn-TiO 2 nano-composite coatings were investigated by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The mechanical properties of coatings including microhardness and wear resistance were studied. The results indicate that the incorporation of TiO 2 nanoparticle can significantly influence the properties of Cu-Sn-Zn coatings. The microhardness of Cu-Sn-Zn coatingmore » was increased to 383 HV from 330 HV with 1 g/L TiO 2 addition. Also, the corrosion resistance of coating was enhanced. The effects of TiO 2 nanoparticle concentration on the microstructure, mechanical properties and corrosion resistance of Cu-Sn-Zn-TiO 2 nano-composite coatings were discussed.« less

Biofunctional composite coating architectures based on polycaprolactone and nanohydroxyapatite for controlled corrosion activity and enhanced biocompatibility of magnesium AZ31 alloy.

PubMed

Zomorodian, A; Garcia, M P; Moura E Silva, T; Fernandes, J C S; Fernandes, M H; Montemor, M F

2015-03-01

In this work a biofunctional composite coating architecture for controlled corrosion activity and enhanced cellular adhesion of AZ31 Mg alloys is proposed. The composite coating consists of a polycaprolactone (PCL) matrix modified with nanohydroxyapatite (HA) applied over a nanometric layer of polyetherimide (PEI). The protective properties of the coating were studied by electrochemical impedance spectroscopy (EIS), a non-disturbing technique, and the coating morphology was investigated by field emission scanning electron microscopy (FE-SEM). The results show that the composite coating protects the AZ31 substrate. The barrier properties of the coating can be optimized by changing the PCL concentration. The presence of nanohydroxyapatite particles influences the coating morphology and decreases the corrosion resistance. The biocompatibility was assessed by studying the response of osteoblastic cells on coated samples through resazurin assay, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The results show that the polycaprolactone to hydroxyapatite ratio affects the cell behavior and that the presence of hydroxyapatite induces high osteoblastic differentiation. Copyright © 2014 Elsevier B.V. All rights reserved.

Microstructure and properties of Cu-Sn-Zn-TiO 2 nano-composite coatings on mild steel

DOE PAGES

Gao, Weidong; Cao, Di; Jin, Yunxue; ...

2018-04-18

Cu-Sn-Zn coatings have been widely used in industry for their unique properties, such as good conductivity, high corrosion resistance and excellent solderability. To further improve the mechanical performance of Cu-Sn-Zn coatings, powder-enhanced method was applied and Cu-Sn-Zn-TiO 2 nano-composite coatings with different TiO 2 concentration were fabricated. The microstructure of Cu-Sn-Zn-TiO 2 nano-composite coatings were investigated by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The mechanical properties of coatings including microhardness and wear resistance were studied. The results indicate that the incorporation of TiO 2 nanoparticle can significantly influence the properties of Cu-Sn-Zn coatings. The microhardness of Cu-Sn-Zn coatingmore » was increased to 383 HV from 330 HV with 1 g/L TiO 2 addition. Also, the corrosion resistance of coating was enhanced. The effects of TiO 2 nanoparticle concentration on the microstructure, mechanical properties and corrosion resistance of Cu-Sn-Zn-TiO 2 nano-composite coatings were discussed.« less

Flexural Fatigue Behavior of an EBC CMC Composite System In Air and Steam at High Temperature

NASA Technical Reports Server (NTRS)

Jaskowiak, Martha; Bur, Michael; Harder, Bryan; Gorican, Daniel

2017-01-01

Both coated and uncoated SiCSiC ceramic matrix composite (CMC) samples were tested in flexure under sustained peak low cycle fatigue (SPLCF) conditions in air or steam at elevated temperatures. The SiCSiC composites were reinforced with 2-D plies of boron nitride coated Hi-Nicalon Type-S SiC fibers which were woven as 5 harness satin (5HS) cloth. The composites were densified by chemical vapor infiltration (CVI) followed by slurry melt infiltration (SMI). A multilayer barium strontium aluminosilicate (BSAS) coating was applied to the samples by a plasma spray method. Fatigue loading limits were determined from monotonic flexure tests at room temperature and 1200oC. Stress levels under the proportional limit of the composite material were selected for the SPLCF tests. After cyclic testing, the composites were evaluated to determine crack propagation and failure modes in the coated and uncoated composites. Microstructural examination was used to identify coating degradation and failure modes of the EBCCMC system.

Coating effects on thermal properties of carbon carbon and carbon silicon carbide composites for space thermal protection systems

NASA Astrophysics Data System (ADS)

Albano, M.; Morles, R. B.; Cioeta, F.; Marchetti, M.

2014-06-01

Many are the materials for hot structures, but the most promising one are the carbon based composites nowadays. This is because they have good characteristics with a high stability at high temperatures, preserving their mechanical properties. Unfortunately, carbon reacts rapidly with oxygen and the composites are subjected to oxidation degradation. From this point of view CC has to be modified in order to improve its thermal and oxidative resistance. The most common solutions are the use of silicon carbide into the carbon composites matrix (SiC composites) to make the thermal properties increase and the use of coating on the surface in order to protect the composite from the space plasma effects. Here is presented an experimental study on coating effects on these composites. Thermal properties of coated and non coated materials have been studied and the thermal impact on the matrix and surface degradation is analyzed by a SEM analysis.

Assessment of iron status in settings of inflammation: challenges and potential approaches.

PubMed

Suchdev, Parminder S; Williams, Anne M; Mei, Zuguo; Flores-Ayala, Rafael; Pasricha, Sant-Rayn; Rogers, Lisa M; Namaste, Sorrel Ml

2017-12-01

The determination of iron status is challenging when concomitant infection and inflammation are present because of confounding effects of the acute-phase response on the interpretation of most iron indicators. This review summarizes the effects of inflammation on indicators of iron status and assesses the impact of a regression analysis to adjust for inflammation on estimates of iron deficiency (ID) in low- and high-infection-burden settings. We overviewed cross-sectional data from 16 surveys for preschool children (PSC) ( n = 29,765) and from 10 surveys for nonpregnant women of reproductive age (WRA) ( n = 25,731) from the Biomarkers Reflecting the Inflammation and Nutritional Determinants of Anemia (BRINDA) project. Effects of C-reactive protein (CRP) and α1-acid glycoprotein (AGP) concentrations on estimates of ID according to serum ferritin (SF) (used generically to include plasma ferritin), soluble transferrin receptor (sTfR), and total body iron (TBI) were summarized in relation to infection burden (in the United States compared with other countries) and population group (PSC compared with WRA). Effects of the concentrations of CRP and AGP on SF, sTfR, and TBI were generally linear, especially in PSC. Overall, regression correction changed the estimated prevalence of ID in PSC by a median of +25 percentage points (pps) when SF concentrations were used, by -15 pps when sTfR concentrations were used, and by +14 pps when TBI was used; the estimated prevalence of ID in WRA changed by a median of +8 pps when SF concentrations were used, by -10 pps when sTfR concentrations were used, and by +3 pps when TBI was used. In the United States, inflammation correction was done only for CRP concentrations because AGP concentrations were not measured; regression correction for CRP concentrations increased the estimated prevalence of ID when SF concentrations were used by 3 pps in PSC and by 7 pps in WRA. The correction of iron-status indicators for inflammation with the use of regression correction appears to substantially change estimates of ID prevalence in low- and high-infection-burden countries. More research is needed to determine the validity of inflammation-corrected estimates, their dependence on the etiology of inflammation, and their applicability to individual iron-status assessment in clinical settings.

Impact of Nanometer Graphite Addition on the Anti-deliquescence and Tribological Properties of Ni/MoS2 Lubricating Coating

NASA Astrophysics Data System (ADS)

Zhang, S.; Li, G. L.; Wang, H. D.; Xu, B. S.; Ma, G. Z.

In order to improve the long-standing problem of MoS2 coating that lubrication performance drop dramatic after storage in humid air, using nano-composite electro brush plating technology and Ni/MoS2-C combination coating with thinness of 100 μm was succeed deposited on GCr15 substrate. Microstructure, surface morphology and elements of this composite coating were analyzed using SEM, XPS and TEM while phase structure was tested by XRD. The tribological properties of this composite coating were tested by MSTS-1; Test the preceding tribological properties of Ni/MoS2-C composite coatings to the pure Ni/MoS2 after different period storage at room temperature and 100% relative humidity atmosphere of 12 h, 24 h, and 48 h as well as the element of the chemical changes. Research shows that there is a small amount of MoS2 in pure MoS2 coatings behind a 12 hours storage in humid air became MoO3 and the tribological performance decreased significantly followed, in the same conditions composite coating with nanometer graphite addition get a preferably tribological properties while the hardness of this coating was improved by the nanometer graphite addition and combination plating showed a well duration tribological properties as a result.

Calcium phosphate/chitosan composite coating: Effect of different concentrations of Mg2+ in the m-SBF on its bioactivity

NASA Astrophysics Data System (ADS)

Zhang, Jie; Dai, Changsong; Wei, Jie; Wen, Zhaohui; Zhang, Shujuan; Lin, Lemin

2013-09-01

The purpose of this study was to investigate the effect of different concentration of Mg2+ in a modified simulated body fluid (m-SBF) on the bioactivity of calcium phosphate/chitosan composite coating. Calcium phosphate/chitosan composite coating was prepared on graphite substrate via electrophoretic deposition (EPD) followed by conversion in a phosphate buffer solution (PBS). The obtained samples were soaked in the m-SBF containing different concentration of Mg2+ for different times. And then, the composite coatings were assessed using X-ray diffractometer (XRD), Fourier-transformed infrared spectroscopy (FTIR), Raman spectra, and scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS). The soaking solution was evaluated by inductively coupled plasma optical emission spectrometer (ICP-OES) test. The analytical results showed that hydroxyapatite (HA) and bone-like apatite (HCA) grew on the surface of calcium phosphate/chitosan composite coating after incubation in different m-SBF. With Mg2+ concentration in m-SBF increased from 1× Mg to 10× Mg, HA in the composite coating first presented a dissolving process and then a precipitating one slowly, while HCA presented a growing trend, continuously. The increasing of Mg2+ concentration in the m-SBF inhibited the total growing process of HA and HCA as a whole. The structure of the composite coating changed from spherical into irregular morphology with the concentration of Mg2+ increasing from 1× Mg to 10× Mg. Over all, with the Mg2+ concentration increasing, the bioactivity of calcium phosphate/chitosan composite coating tended to decrease.

Preparation & characterization of SiO2 interface layer by dip coating technique on carbon fibre for Cf/SiC composites

NASA Astrophysics Data System (ADS)

Kumar, Kundan; Jariwala, C.; Pillai, R.; Chauhan, N.; Raole, P. M.

2015-08-01

Carbon fibres (Cf) are one of the most important reinforced materials for ceramic matrix composites such as Cf - SiC composites and they are generally sought for high temperature applications in as space application, nuclear reactor and automobile industries. But the major problem arise when Cf reinforced composites exposed to high temperature in an oxidizing environment, Cf react with oxygen and burnt away. In present work, we have studied the effect of silica (SiO2) coating as a protective coating on Cf for the Cf / SiC composites. The silica solution prepared by the sol-gel process and coating on Cf is done by dip coating technique with varying the withdrawing speed i.e. 2, 5, 8 mm/s with fixed dipping cycle (3 Nos.). The uniform silica coating on the Cf is shown by the Scanning Electron Microscope (SEM) analysis. The tensile test shows the increase in tensile strength with respect to increase in withdrawing speed. The isothermal oxidation analysis confirmed enhancement of oxidation resistance of silica coated Cf as compared tothe uncoated Cf.

Preparation and Investigation of Electrodeposited Ni-NANO-Cr2O3 Composite Coatings

NASA Astrophysics Data System (ADS)

Jiang, Jibo; Feng, Chenqi; Qian, Wei; Yu, Libin; Ye, Fengying; Zhong, Qingdong; Han, Sheng

2016-12-01

The electrodeposition of Ni-nano-Cr2O3 composite coatings was studied in electrolyte containing different contents of Cr2O3 nanoparticles (Cr2O3 NPs) on mild steel surfaces. Some techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness, the potentiodynamic polarization curves (Tafel) and electrochemical impedance spectroscopy (EIS) were used to compare pure Ni coatings and Ni-nano-Cr2O3 composite coatings. The results show that the incorporation of Cr2O3 NPs resulted in an increase of hardness and corrosion resistance, and the maximum microhardness of Ni-nano-Cr2O3 composite coatings reaches about 495 HV. The coatings exhibit an active-passive transition and relatively large impedance values. Moreover, the effect of Cr2O3 NPs on Ni electrocrystallization is also investigated by cyclic voltammetry (CV) and EIS spectroscopy, which demonstrates that the nature of Ni-based composite coatings changes attributes to Cr2O3 NPs by offering more nucleation sites and less charge transfer resistance.

Review of Research Work on Ti-BASED Composite Coatings

NASA Astrophysics Data System (ADS)

Gabbitas, Brian; Salman, Asma; Zhang, Deliang; Cao, Peng

The service life of industrial components is limited predominantly by Chemical corrosion/mechanical wear. The project is concerned with the investigation of the capability of Ti(Al,O)/Al2O3 coatings to improve the service life of tool steel (H13) used for dies in aluminium high pressure die casting. This paper gives a general review on the research work conducted at the University of Waikato on producing and evaluating the titanium/alumina based composite coatings. The powder feedstocks for making the composite coatings were produced by high energy mechanical milling of a mixture of Al and TiO2 powders in two different molar ratios followed by a thermal reaction process. The feedstocks were then thermally sprayed using a high velocity air-fuel (HVAF) technique on H13 steel substrates to produce a Ti(Al,O)/Al2O3 composite coatings. The performance of the coating was assessed in terms of thermal shock resistance and reaction kinetics with molten aluminium. The composite powders and coatings were characterized using scanning electron microscopy (SEM), optical microscopy and X-ray diffractometry (XRD).

A novel and facile strategy for highly flame retardant polymer foam composite materials: Transforming silicone resin coating into silica self-extinguishing layer.

PubMed

Wu, Qian; Zhang, Qian; Zhao, Li; Li, Shi-Neng; Wu, Lian-Bin; Jiang, Jian-Xiong; Tang, Long-Cheng

2017-08-15

In this study, a novel strategy was developed to fabricate highly flame retardant polymer foam composite materials coated by synthesized silicone resin (SiR) polymer via a facile dip-coating processing. Applying the SiR polymer coating, the mechanical property and thermal stability of SiR-coated polymer foam (PSiR) composites are greatly enhanced without significantly altering their structure and morphology. The minimum oxygen concentration to support the combustion of foam materials is greatly increased, i.e. from LOI 14.6% for pure foam to LOI 26-29% for the PSiR composites studied. Especially, adjusting pendant group to SiOSi group ratio (R/Si ratio) of SiRs produces highly flame retardant PSiR composites with low smoke toxicity. Cone calorimetry results demonstrate that 44-68% reduction in the peak heat release rate for the PSiR composites containing different R/Si ratios over pure foam is achieved by the presence of appropriate SiR coating. Digital and SEM images of post-burn chars indicate that the SiR polymer coating can be transformed into silica self-extinguishing porous layer as effective inorganic barrier effect, thus preserving the polymer foam structure from fire. Our results show that the SiR dip-coating technique is a promising strategy for producing flame retardant polymer foam composite materials with improved mechanical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Composite neutron absorbing coatings for nuclear criticality control

DOEpatents

Wright, Richard N.; Swank, W. David; Mizia, Ronald E.

2005-07-19

Thermal neutron absorbing composite coating materials and methods of applying such coating materials to spent nuclear fuel storage systems are provided. A composite neutron absorbing coating applied to a substrate surface includes a neutron absorbing layer overlying at least a portion of the substrate surface, and a corrosion resistant top coat layer overlying at least a portion of the neutron absorbing layer. An optional bond coat layer can be formed on the substrate surface prior to forming the neutron absorbing layer. The neutron absorbing layer can include a neutron absorbing material, such as gadolinium oxide or gadolinium phosphate, dispersed in a metal alloy matrix. The coating layers may be formed by a plasma spray process or a high velocity oxygen fuel process.

Silicon-doped boron nitride coated fibers in silicon melt infiltrated composites

DOEpatents

Corman, Gregory Scot; Luthra, Krishan Lal

2002-01-01

A fiber-reinforced silicon-silicon carbide matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is produced. The invention also provides a method for protecting the reinforcing fibers in the silicon-silicon carbide matrix composites by coating the fibers with a silicon-doped boron nitride coating.

Silicon-doped boron nitride coated fibers in silicon melt infiltrated composites

DOEpatents

Corman, Gregory Scot; Luthra, Krishan Lal

1999-01-01

A fiber-reinforced silicon--silicon carbide matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is produced. The invention also provides a method for protecting the reinforcing fibers in the silicon--silicon carbide matrix composites by coating the fibers with a silicon-doped boron nitride coating.

Aqueous vinylidene fluoride polymer coating composition

NASA Technical Reports Server (NTRS)

Bartoszek, Edward J. (Inventor); Christofas, Alkis (Inventor)

1978-01-01

A water-based coating composition which may be air dried to form durable, fire resistant coatings includes dispersed vinylidene fluoride polymer particles, emulsified liquid epoxy resin and a dissolved emulsifying agent for said epoxy resin which agent is also capable of rapidly curing the epoxy resin upon removal of the water from the composition.

Preparation and properties of in-situ growth of carbon nanotubes reinforced hydroxyapatite coating for carbon/carbon composites.

PubMed

Liu, Shoujie; Li, Hejun; Su, Yangyang; Guo, Qian; Zhang, Leilei

2017-01-01

Carbon nanotubes (CNTs) possess excellent mechanical properties for their role playing in reinforcement as imparting strength to brittle hydroxyapatite (HA) bioceramic coating. However, there are few reports relating to the in-situ grown carbon nanotubes reinforced hydroxyapatite (CNTs-HA) coating. Here we demonstrate the potential application in reinforcing biomaterials by an attempt to use in-situ grown of CNTs strengthen HA coating, using a combined method composited of injection chemical vapor deposition (ICVD) and pulsed electrodeposition. The microstructure, phases and chemical compositions of CNTs-HA coatings were characterized by various advanced methods. The scanning electron microscopy (SEM) images indicated that CNTs-HA coatings avoided the inhomogeneous dispersion of CNTs inside HA coating. The result show that the interfacial shear strength between CNTs-HA coating and the C/C composite matrix reaches to 12.86±1.43MPa. Potenitodynamic polarization and electrochemical impedance spectroscopy (EIS) studies show that the content of CNTs affects the corrosion resistance of CNTs-HA coating. Cell culturing and simulated body fluid test elicit the biocompatibility with living cells and bioactivity of CNTs-HA coatings, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of gas tunnel type plasma sprayed hydroxyapatite-nanostructure titania composite coatings

NASA Astrophysics Data System (ADS)

Yugeswaran, S.; Kobayashi, A.; Ucisik, A. Hikmet; Subramanian, B.

2015-08-01

Hydroxyapatite (HA) can be coated onto metal implants as a ceramic biocompatible coating to bridge the growth between implants and human tissue. Meanwhile many efforts have been made to improve the mechanical properties of the HA coatings without affecting its bioactivity. In the present study, nanostructure titania (TiO2) was mixed with HA powder and HA-nanostructure TiO2 composite coatings were produced by gas tunnel type plasma spraying torch under optimized spraying conditions. For this purpose, composition of 10 wt% TiO2 + 90 wt% HA, 20 wt% TiO2 + 80 wt% HA and 30 wt% TiO2 + 70 wt% HA were selected as the feedstock materials. The phase, microstructure and mechanical properties of the coatings were characterized. The obtained results validated that the increase in weight percentage of nanostructure TiO2 in HA coating significantly increased the microhardness, adhesive strength and wear resistance of the coatings. Analysis of the in vitro bioactivity and cytocompatibility of the coatings were done using conventional simulated body fluid (c-SBF) solution and cultured green fluorescent protein (GFP) labeled marrow stromal cells (MSCs) respectively. The bioactivity results revealed that the composite coating has bio-active surface with good cytocompatibility.

Cross-linked gelatin/nanoparticles composite coating on micro-arc oxidation film for corrosion and drug release

NASA Astrophysics Data System (ADS)

Xu, Xinhua; Lu, Ping; Guo, Meiqing; Fang, Mingzhong

2010-02-01

A composite coating which could control drug release and biocorrosion of magnesium alloy stent materials WE42 was prepared. This composite coating was fabricated on the surface of the micro-arc oxidation (MAO) film of the magnesium alloy, WE42, by mixing different degrees of cross-linked gelatin with well-dispersed poly( DL-lactide-co-glycolide) (PLGA) nanoparticles. The PLGA nanoparticles were prepared by emulsion solvent evaporation/extraction technique. Nano ZS laser diffraction particle size analyzer detected that the size of the nanoparticles to be 150-300 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) was used to analyze the morphology of the nanoparticles and the composite coating. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion behavior of the composite coating. Drug release was determined by ultraviolet-visible (UV-vis) spectrophotometer. The corrosion resistance of the composite coating was improved by preventing the corrosive ions from diffusing to the MAO films. The drug release rate of paclitaxel (PTX) exhibited a nearly linear sustained-release profile with no significant burst releases.

Tribological properties of epoxy composite coatings reinforced with functionalized C-BN and H-BN nanofillers

NASA Astrophysics Data System (ADS)

Yu, Jingjing; Zhao, Wenjie; Wu, Yinghao; Wang, Deliang; Feng, Ruotao

2018-03-01

A series of epoxy resin (EP) composite coatings reinforced with functionalized cubic boron nitride (FC-BN) and functionalized hexagonal boron nitride (FH-BN) were fabricated successfully on 316L stainless steel by hand lay-up technique. The structure properties were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The morphologies were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, UMT-3 tribometer and surface profiler were used to investigate tribological behaviors of as-prepared composite coatings under dry friction and seawater conditions respectively. The results demonstrated that the presence of FC-BN or FH-BN fillers could greatly decrease the friction coefficient (COF) and wear rate of epoxy, in addition, composite coatings possess better tribological properties under seawater condition which was attributed to the lubricating effect of seawater. Moreover, FC-BN endows the composite coatings the highest wear resistance, and FH-BN /EP composite coatings exhibited the best friction reduction performance which is attributed to the self-lubricating performance of lamella structure for FH-BN sheet.

Paclitaxel-loaded poly(lactide-co-glycolide)/poly(ethylene vinyl acetate) composite for stent coating by ultrasonic atomizing spray.

PubMed

Yuk, Soon Hong; Oh, Keun Sang; Park, Jinah; Kim, Soon-Joong; Kim, Jung Ho; Kwon, Il Keun

2012-04-01

The mixture of poly(lactide-co-glycolide) (PLGA) and poly(ethylene vinyl acetate) (PEVA) forms a homogeneous liquid in an organic solvent such as tetrahydrofuran, and a phase-separated PLGA/PEVA composite can be prepared from it by evaporating the organic solvent. Exploiting this phenomenon, we designed a novel method of preparing a drug-loaded PLGA/PEVA composite and used it for coating drug-eluting stents (DESs). Paclitaxel (PTX), an anticancer drug, was chosen as a model drug. PLGA acts as a microdepot for PTX, and PEVA provides mechanical strength to the coating material. The presence of PLGA in the PLGA/PEVA composite suppressed PTX crystallization in the coating material, and PTX showed a sustained release rate over more than 30 days. The mechanical strength of the PLGA/PEVA composite was better than that of PEVA used as a control. After coating the stent with a PLGA/PEVA composite using ultrasonic atomizing spray, the morphology of the coated material was observed by scanning electron microscopy, and the release pattern of PTX was measured by high-performance liquid chromatography.

Paclitaxel-loaded poly(lactide-co-glycolide)/poly(ethylene vinyl acetate) composite for stent coating by ultrasonic atomizing spray

PubMed Central

Yuk, Soon Hong; Oh, Keun Sang; Park, Jinah; Kim, Soon-Joong; Kim, Jung Ho; Kwon, Il Keun

2012-01-01

The mixture of poly(lactide-co-glycolide) (PLGA) and poly(ethylene vinyl acetate) (PEVA) forms a homogeneous liquid in an organic solvent such as tetrahydrofuran, and a phase-separated PLGA/PEVA composite can be prepared from it by evaporating the organic solvent. Exploiting this phenomenon, we designed a novel method of preparing a drug-loaded PLGA/PEVA composite and used it for coating drug-eluting stents (DESs). Paclitaxel (PTX), an anticancer drug, was chosen as a model drug. PLGA acts as a microdepot for PTX, and PEVA provides mechanical strength to the coating material. The presence of PLGA in the PLGA/PEVA composite suppressed PTX crystallization in the coating material, and PTX showed a sustained release rate over more than 30 days. The mechanical strength of the PLGA/PEVA composite was better than that of PEVA used as a control. After coating the stent with a PLGA/PEVA composite using ultrasonic atomizing spray, the morphology of the coated material was observed by scanning electron microscopy, and the release pattern of PTX was measured by high-performance liquid chromatography. PMID:27877483

Paclitaxel-loaded poly(lactide-co-glycolide)/poly(ethylene vinyl acetate) composite for stent coating by ultrasonic atomizing spray

NASA Astrophysics Data System (ADS)

Yuk, Soon Hong; Oh, Keun Sang; Park, Jinah; Kim, Soon-Joong; Kim, Jung Ho; Kwon, Il Keun

2012-04-01

The mixture of poly(lactide-co-glycolide) (PLGA) and poly(ethylene vinyl acetate) (PEVA) forms a homogeneous liquid in an organic solvent such as tetrahydrofuran, and a phase-separated PLGA/PEVA composite can be prepared from it by evaporating the organic solvent. Exploiting this phenomenon, we designed a novel method of preparing a drug-loaded PLGA/PEVA composite and used it for coating drug-eluting stents (DESs). Paclitaxel (PTX), an anticancer drug, was chosen as a model drug. PLGA acts as a microdepot for PTX, and PEVA provides mechanical strength to the coating material. The presence of PLGA in the PLGA/PEVA composite suppressed PTX crystallization in the coating material, and PTX showed a sustained release rate over more than 30 days. The mechanical strength of the PLGA/PEVA composite was better than that of PEVA used as a control. After coating the stent with a PLGA/PEVA composite using ultrasonic atomizing spray, the morphology of the coated material was observed by scanning electron microscopy, and the release pattern of PTX was measured by high-performance liquid chromatography.

Cold Spray Deposition of Ni and WC-Reinforced Ni Matrix Composite Coatings

NASA Astrophysics Data System (ADS)

Alidokht, S. A.; Vo, P.; Yue, S.; Chromik, R. R.

2017-12-01

Ni-WC composites are ideal protective coatings against wear and are often fabricated using laser cladding and thermal spray processes, but the high temperatures of these processes result in decarburization, which deteriorates the performance of the coating. Cold spray has the potential to deposit Ni-WC composite coatings and retain the composition of the initial WC feedstock. However, the insignificant plastic deformation of hard WC particles makes it difficult to build up a high WC content coating by cold spray. By using three different WC powder sizes, the effect of feedstock powder size on WC retention was tested. To improve WC retention, a WC/Ni composite powder in mixture with Ni was also sprayed. Microstructural characterization, including the deformed structure of Ni splats, retention, distribution, and fragmentation of WC, was performed by scanning electron microscopy. An improvement in WC retention was achieved using finer WC particles. Significant improvement in WC particles retention was achieved using WC/Ni composite powder, with the WC content in the coating being close to that of the feedstock.

Tribological properties of thermally sprayed TiAl-Al2O3 composite coating

NASA Astrophysics Data System (ADS)

Salman, A.; Gabbitas, B.; Li, J.; Zhang, D.

2009-08-01

The use of thermal spray coatings provides protection to the surfaces operating in severe environments. The main goal of the current work is to investigate the possibility of using a high velocity oxy fuel (HVOF) thermally sprayed wear resistant TiAl/Al2O3 coating on tool steel (H13) which is used for making dies for aluminium high pressure die casting. A feedstock of TiAl/Al2O3 composite powder was produced from a mixture of Al and TiO2 powders by high energy mechanical milling, followed by a thermal reaction process. The feedstock was then thermally sprayed using a high velocity oxy-fuel (HVOF) technique onto H13 steel substrates to produce a composite coating. The present study describes and compares the tribological properties such as friction and sliding wear rate of the coating both at room and high temperature (700°C). The results showed that the composite coating has lower wear rate at high temperature (700°C) than the uncoated H13 sample. At Room temperature without using lubricant there is no much significant difference between the wear rate of the coated and uncoated samples. The experimental results showed that the composite coating has great potential for high temperature application due to its lower wear rate at high temperature in comparison with the uncoated sample at the same temperature. The composite coating was characterized using scanning electron microscopy (SEM), optical microscopy and X-ray diffractometry (XRD). This paper reports the experimental observations and discusses the wear resistance performance of the coatings at room and high temperatures.

Hydroxyapatite/poly(epsilon-caprolactone) composite coatings on hydroxyapatite porous bone scaffold for drug delivery.

PubMed

Kim, Hae-Won; Knowles, Jonathan C; Kim, Hyoun-Ee

2004-01-01

Hydroxyapatite (HA) porous scaffold was coated with HA and polycaprolactone (PCL) composites, and antibiotic drug tetracycline hydrochloride was entrapped within the coating layer. The HA scaffold obtained by a polymeric reticulate method, possessed high porosity ( approximately 87%) and controlled pore size (150-200 microm). Such a well-developed porous structure facilitated usage in a drug delivery system due to its high surface area and blood circulation efficiency. The PCL polymer, as a coating component, was used to improve the brittleness and low strength of the HA scaffold, as well to effectively entrap the drug. To improve the osteoconductivity and bioactivity of the coating layer, HA powder was hybridized with PCL solution to make the HA-PCL composite coating. With alteration in the coating concentration and HA/PCL ratio, the morphology, mechanical properties, and biodegradation behavior were investigated. Increasing the concentration rendered the stems thicker and some pores to be clogged; as well increasing the HA/PCL ratio made the coating surface be rough due to the large amount of HA particles. However, for all concentrations and compositions, uniform coatings were formed, i.e., with the HA particles being dispersed homogeneously in the PCL sheet. With the composite coating, the mechanical properties, such as compressive strength and elastic modulus were improved by several orders of magnitude. These improvements were more significant with thicker coatings, while little difference was observed with the HA/PCL ratio. The in vitro biodegradation of the composite coatings in the phosphate buffered saline solution increased linearly with incubation time and the rate differed with the coating concentration and the HA/PCL ratio; the higher concentration and HA amount caused the increased biodegradation. At short period (<2 h), about 20-30% drug was released especially due to free drug at the coating surface. However, the release rate was sustained for prolonged periods and was highly dependent on the degree of coating dissolution, suggesting the possibility of a controlled drug release in the porous scaffold with HA+PCL coating.

Composite ceria-coated aerogels and methods of making the same

DOEpatents

Eyring, Edward M; Ernst, Richard D; Turpin, Gregory C; Dunn, Brian C

2013-05-07

Ceria-coated aerogels can include an aerogel support material having a stabilized ceria coating thereon. The ceria coating can be formed by solution or vapor deposition of alcogels or aerogels. Additional catalytic metal species can also be incorporated into the coating to form multi-metallic compounds having improved catalytic activity. Further, the ceria coated aerogels retain high surface areas at elevated temperatures. Thus, improvements in catalytic activity and thermal stability can be achieved using these ceria-coated composite aerogels.

Research into properties of wear resistant ceramic metal plasma coatings

NASA Astrophysics Data System (ADS)

Ivancivsky, V. V.; Skeeba, V. Yu; Zverev, E. A.; Vakhrushev, N. V.; Parts, K. A.

2018-03-01

The study considers one of the promising ways to improve the quality of wear resistant plasma ceramic coatings by implementing various powder mixtures. The authors present the study results of the nickel-ceramic and cobalt-ceramic coating properties and describe the specific character of the investigated coatings composition. The paper presents the results of the coating microhardness, chemical and adhesive strength studies. The authors conducted wear resistance tests of composite coatings in comparison with the plasma coatings of initial powder components.

Space environmental effects on LDEF composites: A leading edge coated graphite epoxy panel

NASA Technical Reports Server (NTRS)

George, Pete E.; Dursch, Harry W.; Hill, Sylvester G.

1993-01-01

The electronics module cover for the leading edge (Row D 9) experiment M0003-8 was fabricated from T300 graphite/934 epoxy unidirectional prepreg tape in a (O(sub 2), +/- 45, O(sub 2), +/- 45, 90, 0)(sub s) layup. This 11.75 in x 16.75 in panel was covered with thermal control coatings in three of the four quadrants with the fourth quadrant uncoated. The composite panel experienced different thermal cycling extremes in each quadrant due to the different optical properties of the coatings and bare composite. The panel also experienced ultraviolet (UV) and atomic oxygen (AO) attack as well as micrometeoroid and space debris impacts. An AO reactivity of 0.99 x 10(exp -24) cm(sup 3)/atom was calculated for the bare composite based on thickness loss. The white urethane thermal control coatings (A276 and BMS 1060) prevented AO attack of the composite substrate. However, the black urethane thermal control coating (Z306) was severely eroded by AO, allowing some AO attack of the composite substrate. An interesting banding pattern on the AO eroded bare composite surface was investigated and found to match the dimensions of the graphite fiber tow widths as prepregged. Also, erosion depths were greater in the darker bands. Five micrometeoroid/space debris impacts were cross sectioned to investigate possible structural damage as well as impact/AO interactions. Local crushing and delaminations were found to some extent in all of the impacts. No signs of coating undercutting were observed despite the extensive AO erosion patterns seen in the exposed composite material at the impact sites. An extensive microcrack study was performed on the panel along with modeling of the thermal environment to estimate temperature extremes and thermal shock. The white coated composite substrate displayed almost no microcracking while the black coated and bare composite showed extensive microcracking. Significant AO erosion was seen in many of the cracks in the bare composite.

Selection criteria for wear resistant powder coatings under extreme erosive wear conditions

NASA Astrophysics Data System (ADS)

Kulu, P.; Pihl, T.

2002-12-01

Wear-resistant thermal spray coatings for sliding wear are hard but brittle (such as carbide and oxide based coatings), which makes them useless under impact loading conditions and sensitive to fatigue. Under extreme conditions of erosive wear (impact loading, high hardness of abrasives, and high velocity of abradant particles), composite coatings ensure optimal properties of hardness and toughness. The article describes tungsten carbide-cobalt (WC-Co) systems and self-fluxing alloys, containing tungsten carbide based hardmetal particles [NiCrSiB-(WC-Co)] deposited by the detonation gun, continuous detonation spraying, and spray fusion processes. Different powder compositions and processes were studied, and the effect of the coating structure and wear parameters on the wear resistance of coatings are evaluated. The dependence of the wear resistance of sprayed and fused coatings on their hardness is discussed, and hardness criteria for coating selection are proposed. The so-called “double cemented” structure of WC-Co based hardmetal or metal matrix composite coatings, as compared with a simple cobalt matrix containing particles of WC, was found optimal. Structural criteria for coating selection are provided. To assist the end user in selecting an optimal deposition method and materials, coating selection diagrams of wear resistance versus hardness are given. This paper also discusses the cost-effectiveness of coatings in the application areas that are more sensitive to cost, and composite coatings based on recycled materials are offered.

Solid Particle Erosion Behaviors of Carbon-Fiber Epoxy Composite and Pure Titanium

NASA Astrophysics Data System (ADS)

Cai, Feng; Gao, Feng; Pant, Shashank; Huang, Xiao; Yang, Qi

2016-01-01

Rotor blades of Bell CH-146 Griffon helicopter experience excessive solid particle erosion at low altitudes in desert environment. The rotor blade is made of an advanced light-weight composite which, however, has a low resistance to solid particle erosion. Coatings have been developed and applied to protect the composite blade. However, due to the influence of coating process on composite material, the compatibility between coating and composite base, and the challenges of repairing damaged coatings as well as the inconsistency between the old and new coatings, replaceable thin metal shielding is an alternative approach; and titanium, due to its high-specific strength and better formability, is an ideal candidate. This work investigates solid particle erosion behaviors of carbon-fiber epoxy composite and titanium in order to assess the feasibility of titanium as a viable candidate for erosion shielding. Experiment results showed that carbon-fiber epoxy composite showed a brittle erosion behavior, whereas titanium showed a ductile erosion mode. The erosion rate on composite was 1.5 times of that on titanium at impingement angle 15° and increased to 5 times at impact angle 90°.

Plasma-Sprayed Ti6Al4V Alloy Composite Coatings Reinforced with In Situ Formed TiB-TiN

NASA Astrophysics Data System (ADS)

Anand, Akrity; Das, Mitun; Kundu, Biswanath; Balla, Vamsi Krishna; Bodhak, Subhadip; Gangadharan, S.

2017-12-01

Plasma spraying was used to deposit premixed Ti6Al4V + 15 wt.% BN powder on titanium substrate to fabricate Ti6Al4V matrix composite coatings reinforced with in situ synthesized TiB-TiN. The formation of in situ TiB-TiN reinforcements increased with plasma power. The in situ reaction appears to be complete under present experimental conditions but with considerable oxidation of Ti in the composite coatings. The hardness of composite coatings was 7 times higher (855HV), and the in vitro wear rate (2.4 × 10-5 mm3/N m) was one order of magnitude less than that of titanium substrate. However, the microstructural non-uniformity decreased the corrosion resistance of these composite coatings in Hank's balanced salt solution.

Some Properties of Composite Panels Made from Wood Flour and Recycled Polyethylene

PubMed Central

Ozdemir, Turgay; Mengeloglu, Fatih

2008-01-01

This study investigated the effect of board type (unmodified vs. MAPE modified) on the surface quality and thickness swelling-water absorption properties of recycled high density polyethylene (HDPE) based wood plastic composites. Additionally, two commercially available coatings (cellulosic coating and polyurethane lacquer coating) were also applied to composite surfaces and their adhesion strength, abrasion and scratch resistance, and gloss values were determined. This study showed that modification of the composites with MAPE coupling agent increased the surface smoothness and reduced the water absorption and thickness swelling of the panels. Abrasion resistance of the composites was also improved through MAPE modification. Regardless of board type, higher scratch resistance and gloss values were observed for polyurethane lacquer coated samples compared to those of cellulosic varnish coated ones. Improvement of adhesion strength was also seen on SEM micrographs. PMID:19330092

Effects of Fiber Coating Composition on Mechanical Behavior of Silicon Carbide Fiber-Reinforced Celsian Composites

NASA Technical Reports Server (NTRS)

Bansal, Narottam P.; Elderidge, Jeffrey I.

1998-01-01

Celsian matrix composites reinforced with Hi-Nicalon fibers, precoated with a dual layer of BN/SiC by chemical vapor deposition in two separate batches, were fabricated. Mechanical properties of the composites were measured in three-point flexure. Despite supposedly identical processing, the composite panels fabricated with fibers coated in two batches exhibited substantially different mechanical behavior. The first matrix cracking stresses (sigma(sub mc)) of the composites reinforced with fibers coated in batch 1 and batch 2 were 436 and 122 MPa, respectively. This large difference in sigma(sub mc) was attributed to differences in fiber sliding stresses(tau(sub friction)), 121.2+/-48.7 and 10.4+/-3.1 MPa, respectively, for the two composites as determined by the fiber push-in method. Such a large difference in values of tau(sub friction) for the two composites was found to be due to the difference in the compositions of the interface coatings. Scanning Auger microprobe analysis revealed the presence of carbon layers between the fiber and BN, and also between the BN and SiC coatings in the composite showing lower tau(sub friction). This resulted in lower sigma(sub mc) in agreement with the ACK theory. The ultimate strengths of the two composites, 904 and 759 MPa, depended mainly on the fiber volume fraction and were not significantly effected by tau(sub friction) values, as expected. The poor reproducibility of the fiber coating composition between the two batches was judged to be the primary source of the large differences in performance of the two composites.

Quantum solution to a class of two-party private summation problems

NASA Astrophysics Data System (ADS)

Shi, Run-Hua; Zhang, Shun

2017-09-01

In this paper, we define a class of special two-party private summation (S2PPS) problems and present a common quantum solution to S2PPS problems. Compared to related classical solutions, our solution has advantages of higher security and lower communication complexity, and especially it can ensure the fairness of two parties without the help of a third party. Furthermore, we investigate the practical applications of our proposed S2PPS protocol in many privacy-preserving settings with big data sets, including private similarity decision, anonymous authentication, social networks, secure trade negotiation, secure data mining.

Consistent characterization of semiconductor saturable absorber mirrors with single-pulse and pump-probe spectroscopy.

PubMed

Fleischhaker, R; Krauss, N; Schättiger, F; Dekorsy, T

2013-03-25

We study the comparability of the two most important measurement methods used for the characterization of semiconductor saturable absorber mirrors (SESAMs). For both methods, single-pulse spectroscopy (SPS) and pump-probe spectroscopy (PPS), we analyze in detail the time-dependent saturation dynamics inside a SESAM. Based on this analysis, we find that fluence-dependent PPS at complete spatial overlap and zero time delay is equivalent to SPS. We confirm our findings experimentally by comparing data from SPS and PPS of two samples. We show how to interpret this data consistently and we give explanations for possible deviations.

Overcoming barriers to work participation for patients with postpoliomyelitis syndrome.

PubMed

Ten Katen, Kim; Beelen, Anita; Nollet, Frans; Frings-Dresen, Monique H W; Sluiter, Judith K

2011-01-01

This study aimed to explore the perceived work ability of patients with postpoliomyelitis syndrome (PPS), to identify barriers and factors that are impeding or conducive, respectively, to work participation, and to identify possible interventions. Qualitative cross-sectional interview study with 17 subjects with PPS, 12 women and 5 men, mean age 49 years (SD: 11). Semi-structured interviews were held with the subjects in their homes, with the aid of a topic list. The COREQ criteria list for qualitative research was used as guideline in design and analysis. Thirteen out of 17 subjects rated their work ability six or higher on a scale from 0 to 10. Most subjects worked in an administrative, educational or managerial function. Five subjects stopped working, four worked between 0 and 20 h/week and eight worked between 20 and 40 h/week. Factors conducive to working were physical adaptations in the workplace, accessibility of the workplace and high decision latitude. Barriers to full work ability in PPS patients were high physical job demands, low social support and the symptoms of PPS, especially fatigue and pain. These findings suggest that work-oriented interventions aimed at preventing PPS patients from dropping out of the workforce should primarily focus on reducing physical job demands, arranging adaptations in the workplace and increasing job control.

Sensitivity to binaural timing in bilateral cochlear implant users.

PubMed

van Hoesel, Richard J M

2007-04-01

Various measures of binaural timing sensitivity were made in three bilateral cochlear implant users, who had demonstrated moderate-to-good interaural time delay (ITD) sensitivity at 100 pulses-per-second (pps). Overall, ITD thresholds increased at higher pulse rates, lower levels, and shorter durations, although intersubject differences were evident. Monaural rate-discrimination thresholds, using the same stimulation parameters, showed more substantial elevation than ITDs with increased rate. ITD sensitivity with 6000 pps stimuli, amplitude-modulated at 100 Hz, was similar to that with unmodulated pulse trains at 100 pps, but at 200 and 300 Hz performance was poorer than with unmodulated signals. Measures of sensitivity to binaural beats with unmodulated pulse-trains showed that all three subjects could use time-varying ITD cues at 100 pps, but not 300 pps, even though static ITD sensitivity was relatively unaffected over that range. The difference between static and dynamic ITD thresholds is discussed in terms of relative contributions from initial and later arriving cues, which was further examined in an experiment using two-pulse stimuli as a function of interpulse separation. In agreement with the binaural-beat data, findings from that experiment showed poor discrimination of ITDs on the second pulse when the interval between pulses was reduced to a few milliseconds.

Medicare constrains social workers' and nurses' home care for clients with Alzheimer's disease.

PubMed

Cabin, William D

2015-01-01

The Medicare home health prospective payment system (PPS) has existed for 13 years, yielding significant profits to providers. However, studies indicate many unresolved questions about whether PPS improves patient quality of care, is cost-effective, and reduces patient levels of unmet need. In addition, PPS has undermined the provision of social work home health services. The article presents the views of 29 home health care nurses regarding the impact ofPPS on their care decisions for people with Alzheimer's disease and their caregivers. The nurses identify Alzheimer's disease symptom management and psychosocial needs as phantoms, omnipresent below the surface but not attended to by home care clinicians. The interviews support the greater involvement of social workers to more adequately address the psychosocial needs of Medicare home health patients. The article contends that the current failure to simultaneously address the cost, needs, and quality-of-life issues of people with Alzheimer's disease who are cared for at home is analogous to the end-of-life care situation before passage of the Medicare Hospice Benefit. A collaborative demonstration project--social work and nursing--is proposed to determine how PPS might better address quality of life and costs of home-based people with Alzheimer's disease and their caregivers.

Overview of MST Research

NASA Astrophysics Data System (ADS)

Chapman, B. E.

2017-10-01

MST progress in advancing the RFP for (1) fusion plasma confinement with ohmic heating and minimal external magnetization, (2) predictive capability in toroidal confinement physics, and (3) basic plasma physics is summarized. Validation of key plasma models is a program priority, which is enhanced by programmable power supplies (PPS) to maximize inductive capability. The existing PPS enables access to very low plasma current, down to Ip =0.02 MA. This greatly expands the Lundquist number range S =104 -108 and allows nonlinear, 3D MHD computation using NIMROD and DEBS with dimensionless parameters that overlap those of MST plasmas. A new, second PPS will allow simultaneous PPS control of the Bp and Bt circuits. The PPS also enables MST tokamak operation, thus far focused on disruptions and RMP suppression of runaway electrons. Gyrokinetic modeling with GENE predicts unstable TEM in improved-confinement RFP plasmas. Measured fluctuations have TEM properties including a density-gradient threshold larger than for tokamak plasmas. Turbulent energization of an electron tail occurs during sawtooth reconnection. Probe measurements hint that drift waves are also excited via the turbulent cascade in standard RFP plasmas. Exploration of basic plasma science frontiers in MST RFP and tokamak plasmas is proposed as part of WiPPL, a basic science user facility. Work supported by USDoE.

Loss of motor unit size and quadriceps strength over 10 years in post-polio syndrome.

PubMed

Bickerstaffe, A; van Dijk, J P; Beelen, A; Zwarts, M J; Nollet, F

2014-06-01

To investigate whether strength decline in post-polio syndrome (PPS) results from excessive distal axonal degeneration of enlarged motor units. We assessed changes over 10 years in isometric quadriceps strength, mean motor unit action potential (MUAP) size, root mean squared (RMS) amplitude, and level of interference (LOI) in 47 patients with PPS and 12 healthy controls, using high density surface EMG. At baseline, all patients had symptomatic quadriceps dysfunction, evidenced by transmission defects on single-fibre EMG. MU size and strength declined significantly by 20% and 15%, respectively in patients with PPS. Those with the largest initial MU sizes exhibited the greatest losses of mean MU size (27%) and proportional decreases in quadriceps strength (23%). Initial strength, change in LOI and change in RMS amplitude together explained 35% of the variability in strength changes in patients. MU size of controls did not change, although they lost 29% strength. MU size and strength declined concomitantly in a homogeneous cohort of patients with PPS and quadriceps dysfunction. This long term follow-up study provides evidence that size diminution of enlarged MUs combined with a reduced number of active MUs contributes to the gradual strength decline in PPS. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Optical enhancing durable anti-reflective coating

DOEpatents

Maghsoodi, Sina; Varadarajan, Aravamuthan; Movassat, Meisam

2016-07-05

Disclosed herein are polysilsesquioxane based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In embodiments, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in the polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, Si--OH condensation catalyst and/or nanofillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes including flow coating and roll coating, and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

Synthesis and Characterization of Zr-BASED Amorphous and Crystalline Composite Coating on Ti Substrate by Laser Cladding

NASA Astrophysics Data System (ADS)

Tang, D. M.; Zhang, D. C.; Peng, W.; Luo, Z. C.; Wu, X. Q.; Wang, Y. M.; Lin, J. G.

2014-02-01

A thin strip of a Zr-based alloy with a composition of Zr60Cu25Fe5Al10 (in atom percent) was used as a raw material, and the composite coatings containing Zr-based amorphous phase and crystallites on Ti substrate were fabricated by a one-step laser cladding method without protection. The microstructure, phase constitution, microhardness and wear properties of the coatings were investigated. The results indicate that the microstructure of the coatings is strongly dependent on the laser scanning speed under the conditions of the laser power of 1300 W and laser beam diameter of 6 mm, and the composite coating mainly containing amorphous phase with a small amount of the crystallites can be obtained at the laser scanning speed of 10 mm/s. The composite coating exhibits much higher microhardness than the pure Ti substrate, and thus it behaves superior wear resistance in comparison with the substrate.

Effect of pulse frequency on microstructural, nanomechanical, and wear properties of electrodeposited Ni-TiN composite coatings

NASA Astrophysics Data System (ADS)

Xia, Fafeng; Tian, Jiyu; Ma, Chunyang; Potts, Matt; Guo, Xue

2014-12-01

The current paper reports successful syntheses of Ni-TiN composite coatings by pulse electrodeposition. The effect of pulse frequency on the microstructures, nanomechanical, and wear properties of the coatings was investigated using transmission electron microscopy, X-ray diffraction, nanoindenter, scanning electron microscopy, and wear test instrument. The results showed that the Ni-TiN composite coating prepared at the pulse frequency of 100 Hz showed the presence of a less number of TiN particles and some degrees of aggregation in micro-regions. By contrast, in the Ni-TiN coating deposited at the pulse frequency of 500 Hz, the TiN particles were large in number and dispersed homogeneously, thereby, offering the coating a uniform and fine structure. The average grain diameters of Ni and TiN in the coating prepared at 100 Hz were 154.7 and 44.8 nm, respectively, whereas those for the coating prepared at 500 Hz were 67.3 and 25.9 nm, respectively. The maximum TiN content in the Ni-TiN coating deposited at 800 Hz was approximately 10.5 wt. %. The maximum microhardness and the Young's modulus values for the Ni-TiN composite coatings deposited at 800 Hz were 35.7 GPa and 167.4 GPa, respectively. Furthermore, the Ni-TiN composite coating prepared at 100 Hz had more severe damages, whereas the morphologies of worn surface of the coatings deposited at 500 Hz and 800 Hz were smooth and only a few small pits appeared on the surface.

Deposition of nanostructured fluorine-doped hydroxyapatite-polycaprolactone duplex coating to enhance the mechanical properties and corrosion resistance of Mg alloy for biomedical applications.

PubMed

Bakhsheshi-Rad, H R; Hamzah, E; Kasiri-Asgarani, M; Jabbarzare, S; Iqbal, N; Abdul Kadir, M R

2016-03-01

The present study addressed the synthesis of a bi-layered nanostructured fluorine-doped hydroxyapatite (nFHA)/polycaprolactone (PCL) coating on Mg-2Zn-3Ce alloy via a combination of electrodeposition (ED) and dip-coating methods. The nFHA/PCL composite coating is composed of a thick (70-80 μm) and porous layer of PCL that uniformly covered the thin nFHA film (8-10 μm) with nanoneedle-like microstructure and crystallite size of around 70-90 nm. Electrochemical measurements showed that the nFHA/PCL composite coating presented a high corrosion resistance (R(p)=2.9×10(3) kΩ cm(2)) and provided sufficient protection for a Mg substrate against galvanic corrosion. The mechanical integrity of the nFHA/PCL composite coatings immersed in SBF for 10 days showed higher compressive strength (34% higher) compared with the uncoated samples, indicating that composite coatings can delay the loss of compressive strength of the Mg alloy. The nFHA/PCL coating indicted better bonding strength (6.9 MPa) compared to PCL coating (2.2 MPa). Immersion tests showed that nFHA/PCL composite-coated alloy experienced much milder corrosion attack and more nucleation sites for apatite compared with the PCL coated and uncoated samples. The bi-layered nFHA/PCL coating can be a good alternative method for the control of corrosion degradation of biodegradable Mg alloy for implant applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Electrodeposition and Characterization of Ni-Al2O3 Nanocomposite Coatings on Steel

NASA Astrophysics Data System (ADS)

Akhtar, Khalida; Khan, Zia Ullah; Gul, Muhammad; Zubair, Naila; Shah, Syed Sajjad Ali

2018-05-01

Monodispersed alumina particles were synthesized by the homogeneous precipitation under reflux boiling. The particles were employed as reinforcement additives in the electrodeposited Ni-Al2O3 composite coatings on steel. The deposited pure Ni and Ni-Al2O3 composite coatings were analyzed by SEM, XRD, and microhardness tester. The wear resistance and friction coefficient of the coated samples were determined by using a ball-on-disk tribometer. Furthermore, XRD analysis showed that coating temperature and the presence of particles in the deposited coatings had a noticeable effect on the preferred orientation of the crystalline faces of the nickel grains. Significant differences were noted in the texture coefficient of the pure Ni and Ni-Al2O3 composite coatings produced at different temperatures. These differences were attributed to the changes in the microstructure of the matrix caused by the embedded Al2O3 particles. Results revealed that wear resistance and the friction coefficient were turned out to be higher and smaller, respectively, for the composite coatings as compared to pure Ni coating at a given sliding distance. It was noted that the corrosion resistance of these specimens increased in the following order: bare substrate < pure Ni coating < Ni-Al2O3 nanocomposite coatings.

The Effect of Compositional Tailoring on the Thermal Expansion and Tribological Properties of PS300: A Solid Lubricant Composite Coating

NASA Technical Reports Server (NTRS)

DellaCorte, C.; Fellenstein, J. A.

1996-01-01

This paper describes a research program in which the goal is to alter the thermal expansion coefficient of a composite solid lubricant coating, PS300, by compositional tailoring. PS300 is a plasma sprayed coating consisting of chrome oxide, silver and barium fluoride/calcium fluoride eutectic in NiCr binder. By adjusting the composition, the thermal expansion coefficient can be altered, and hence chosen, to more closely match a selected substrate preventing coating spallation at extreme temperatures. Thermal expansion coefficients (CTE) for a variety of compositions were measured from 25 to 800 C using a commercial dilatometer. The CTE's ranged from 7.0 to 13 x lO(exp -6)/deg C depending on the binder content. Subsequent tribological testing of a modified composition indicated that friction and wear properties were relatively insensitive to compositional tailoring.

In situ synthesis of mesoporous polyvinyl alcohol/hydroxyapatite composites for better biomedical coating adhesion

NASA Astrophysics Data System (ADS)

Hussain, Riaz; Tabassum, Sobia; Gilani, Mazhar Amjad; Ahmed, Ejaz; Sharif, Ahsan; Manzoor, Faisal; Shah, Asma Tufail; Asif, Anila; Sharif, Faiza; Iqbal, Farasat; Siddiqi, Saadat Anwar

2016-02-01

Hydroxyapatite (HA) shows diverse biomedical applications as bone filler and coating material for metal implants to enhance osteoconduction. Four different PVAHA composites were synthesized in situ by an economical co-precipitation wet methodology. The FTIR spectra of PVAHA composites showed characteristic signals of HA and PVA. The BET surface area of PVAHA composites were in range of 41.3-63.7 m2/g. The composites showed type IV nitrogen adsorption/desorption isotherm, a characteristic for mesoporous material. The pore diameter range (6.3-8.1 nm) of PVAHA composites also confirmed their mesoporous nature. The Barrett-Joyner-Halenda (BJH) pore size distribution curves indicated a narrow pore size distribution. To obtain a homogeneous crack free coating with EPD on stainless steel (SS) plates, different parameters such as PVA percentages in PVAHA composites, solvent, deposition time and voltage were optimized. The PVAHA composites were stable after EPD as confirmed by FTIR spectra recorded before and after EPD. The SEM images of the coating showed a homogeneous morphology. The thickness of the coating was controlled by varying voltage and time. The best results were obtained with c-PVAHA composite at 30 volts for 5-10 min and current density was around 4.5 to 5 mA. The adhesion strength of c-PVAHA coating was measured by using ASTM standard F1044-99. The average value was approximately 9.328 ± 1.58 MPa.

Property Evaluation and Damage Evolution of Environmental Barrier Coatings and Environmental Barrier Coated SiC/SiC Ceramic Matrix Composite Sub-Elements

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Halbig, Michael; Jaskowiak, Martha; Hurst, Janet; Bhatt, Ram; Fox, Dennis S.

2014-01-01

This paper describes recent development of environmental barrier coatings on SiC/SiC ceramic matrix composites. The creep and fatigue behavior at aggressive long-term high temperature conditions have been evaluated and highlighted. Thermal conductivity and high thermal gradient cyclic durability of environmental barrier coatings have been evaluated. The damage accumulation and complex stress-strain behavior environmental barrier coatings on SiCSiC ceramic matrix composite turbine airfoil subelements during the thermal cyclic and fatigue testing of have been also reported.

Metal matrix coated fiber composites and the methods of manufacturing such composites

DOEpatents

Weeks, Jr., Joseph K.; Gensse, Chantal

1993-01-01

A fiber coating which allows ceramic or metal fibers to be wetted by molten metals is disclosed. The coating inhibits degradation of the physical properties caused by chemical reaction between the fiber and the coating itself or between the fiber and the metal matrix. The fiber coating preferably includes at least a wetting layer, and in some applications, a wetting layer and a barrier layer between the fiber and the wetting layer. The wetting layer promotes fiber wetting by the metal matrix. The barrier layer inhibits fiber degradation. The fiber coating permits the fibers to be infiltrated with the metal matrix resulting in composites having unique properties not obtainable in pure materials.

Metal matrix coated fiber composites and the methods of manufacturing such composites

DOEpatents

Weeks, J.K. Jr.; Gensse, C.

1993-09-14

A fiber coating which allows ceramic or metal fibers to be wetted by molten metals is disclosed. The coating inhibits degradation of the physical properties caused by chemical reaction between the fiber and the coating itself or between the fiber and the metal matrix. The fiber coating preferably includes at least a wetting layer, and in some applications, a wetting layer and a barrier layer between the fiber and the wetting layer. The wetting layer promotes fiber wetting by the metal matrix. The barrier layer inhibits fiber degradation. The fiber coating permits the fibers to be infiltrated with the metal matrix resulting in composites having unique properties not obtainable in pure materials. 8 figures.

LSP/MAO composite bio-coating on AZ80 magnesium alloy for biomedical application.

PubMed

Xiong, Ying; Hu, Qiang; Song, Renguo; Hu, Xiaxia

2017-06-01

A composite bio-coating was fabricated on AZ80 magnesium (Mg) alloy by using micro-arc oxidation (MAO) under the pretreatment of laser shock peening (LSP) in order to improve the bio-corrosion resistance and the mechanical integrity. LSP treatment could induce grain refinement and compressive residual stress field on the surface of material. MAO bio-coating was grown in alkaline electrolyte with hydroxyapatite (HA, Ca 10 (PO4) 6 (OH) 2 ) to improve the biological properties of the material. The microstructure, element and phase composition for untreated based material (BM) and treated samples (LSP layer, MAO bio-coating and LSP/MAO composite bio-coating) were investigated by transmission electron microscopy (TEM), scanning electron microscope (SEM), energy dispersion spectroscopy (EDS) and X-ray diffraction (XRD). Electrochemical tests and slow strain rate tensile (SSRT) tests were used to evaluate the corrosion resistance and the stress corrosion susceptibility in simulated body fluid (SBF). The results indicated that LSP/MAO composite bio-coating can not only improve the corrosion resistance of Mg alloy substrate evidently but also increase the mechanical properties in SBF compared to LSP layer and MAO bio-coating. Mg alloy treated by LSP/MAO composite technique should be better suited as biodegradable orthopedic implants. Copyright © 2017 Elsevier B.V. All rights reserved.

Microstructure characteristics of Ni/WC composite cladding coatings

NASA Astrophysics Data System (ADS)

Yang, Gui-rong; Huang, Chao-peng; Song, Wen-ming; Li, Jian; Lu, Jin-jun; Ma, Ying; Hao, Yuan

2016-02-01

A multilayer tungsten carbide particle (WCp)-reinforced Ni-based alloy coating was fabricated on a steel substrate using vacuum cladding technology. The morphology, microstructure, and formation mechanism of the coating were studied and discussed in different zones. The microstructure morphology and phase composition were investigated by scanning electron microscopy, optical microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. In the results, the coating presents a dense and homogeneous microstructure with few pores and is free from cracks. The whole coating shows a multilayer structure, including composite, transition, fusion, and diffusion-affected layers. Metallurgical bonding was achieved between the coating and substrate because of the formation of the fusion and diffusion-affected layers. The Ni-based alloy is mainly composed of γ-Ni solid solution with finely dispersed Cr7C3/Cr23C6, CrB, and Ni+Ni3Si. WC particles in the composite layer distribute evenly in areas among initial Ni-based alloying particles, forming a special three-dimensional reticular microstructure. The macrohardness of the coating is HRC 55, which is remarkably improved compared to that of the substrate. The microhardness increases gradually from the substrate to the composite zone, whereas the microhardness remains almost unchanged in the transition and composite zones.

Sapphire reinforced alumina matrix composites

NASA Technical Reports Server (NTRS)

Jaskowiak, Martha H.; Setlock, John A.

1994-01-01

Unidirectionally reinforced A1203 matrix composites have been fabricated by hot pressing. Approximately 30 volume % of either coated or uncoated sapphire fiber was used as reinforcement. Unstabilized ZrO2 was applied as the fiber coating. Composite mechanical behavior was analyzed both after fabrication and after additional heat treatment. The results of composite tensile tests were correlated with fiber-matrix interfacial shear strengths determined from fiber push-out tests. Substantially higher strength and greater fiber pull-out were observed for the coated fiber composites for all processing conditions studied. The coated fiber composites retained up to 95% and 87% of their as-fabricated strength when heat treated at 14000C for 8 or 24 hours, respectively. Electron microscopy analysis of the fracture surfaces revealed extensive fiber pull-out both before and after heat treatment.

Terahertz detection and identification of defects in layered polymer composites and composite coatings

NASA Astrophysics Data System (ADS)

Lopato, Przemyslaw; Chady, Tomasz

2013-03-01

Modern industry makes more and more extensive use of various composite materials. In this paper, for the purposes of various composite materials evaluation, the terahertz imaging method is presented. Basalt fibre-reinforced composites and polymeric anticorrosion coatings are considered. Basalt fibre composites are the innovative materials that are being increasingly used in modern industry. The paper also briefly introduces a specific type of complex coating of steel applied in the industry (e.g. oil or chemical). Two methods of defects detection in the mentioned structures are presented. The first method is based on a system identification, whereas the second one is on the estimation of time-domain signal parameters. Finally, the results achieved during terahertz inspection of coatings are compared with those obtained using active thermography.

Chitosan reinforced apatite-wollastonite coating by electrophoretic deposition on titanium implants.

PubMed

Sharma, Smriti; Soni, Vivek P; Bellare, Jayesh R

2009-07-01

A novel bioactive porous apatite-wollastonite/chitosan composite coating was prepared by electrophoretic deposition. The influence of synthesis parameters like pH of suspension and current density was studied and optimized. X-ray diffraction confirmed crystalline phase of apatite-wollastonite in powder as well as composite coating with coat crystallinity of 65%. Scanning electron microscope showed that the porosity had interconnections with good homogeneity between the phases. The addition of chitosan increased the adhesive strength of the composite coating. Young's modulus of the coating was found to be 9.23 GPa. One of our key findings was sheet-like apatite growth unlike ball-like growth found in bioceramics. Role of chitosan was studied in apatite growth mechanism in simulated body fluid. In presence of chitosan, dense negatively charged surface with homogenous nucleation was the primary factor for sheet-like evolution of apatite layer. The results suggest that incorporation of chitosan with apatite-wollastonite in composite coating could provide excellent in vitro bioactivity with enhanced mechanical properties.

Effects of graphene plates' adoption on the microstructure, mechanical properties, and in vivo biocompatibility of calcium silicate coating.

PubMed

Xie, Youtao; Li, Hongqin; Ding, Chuanxian; Zheng, Xuebin; Li, Kai

2015-01-01

Calcium silicate (CS) ceramic is a good coating candidate for biomedical implants to improve biocompatibility and accelerate early osseointegration. However, the poor fracture toughness and wear resistance of this ceramic material restricts the long-term performance of implants. In this study, graphene plates (GPs) were used as reinforcement to improve the mechanical properties of CS coating. Composite coating containing 1.5 weight % GPs was prepared by vacuum plasma spraying technology. The good survival of the GPs in the composite coating was demonstrated by Raman analysis, although the defects of the GPs were increased after plasma spraying. Effects of the GPs' adoption on the microstructure of the coating were studied by scanning electron microscopy and transmission electron microscopy. Results showed that the GPs were homogenously distributed in the CS grains interface or enwrapped on the particles, and exhibited good wetting behavior with the CS matrix. The wear properties of the composite coating were obviously enhanced by the reinforcement of GPs. The reinforcement mechanism was attributed to the enhanced micro-hardness and interfacial bonding of the particles in the coating. In vivo experiments demonstrated that the composite coating possessed similarly good biocompatibility compared to pure CS coating. The bone-implant contact ratio reached 84.3%±7.4% for GPs/CS coating and 79.6%±9.4% for CS coating after 3 months' implantation.

Effects of graphene plates’ adoption on the microstructure, mechanical properties, and in vivo biocompatibility of calcium silicate coating

PubMed Central

Xie, Youtao; Li, Hongqin; Ding, Chuanxian; Zheng, Xuebin; Li, Kai

2015-01-01

Calcium silicate (CS) ceramic is a good coating candidate for biomedical implants to improve biocompatibility and accelerate early osseointegration. However, the poor fracture toughness and wear resistance of this ceramic material restricts the long-term performance of implants. In this study, graphene plates (GPs) were used as reinforcement to improve the mechanical properties of CS coating. Composite coating containing 1.5 weight % GPs was prepared by vacuum plasma spraying technology. The good survival of the GPs in the composite coating was demonstrated by Raman analysis, although the defects of the GPs were increased after plasma spraying. Effects of the GPs’ adoption on the microstructure of the coating were studied by scanning electron microscopy and transmission electron microscopy. Results showed that the GPs were homogenously distributed in the CS grains interface or enwrapped on the particles, and exhibited good wetting behavior with the CS matrix. The wear properties of the composite coating were obviously enhanced by the reinforcement of GPs. The reinforcement mechanism was attributed to the enhanced micro-hardness and interfacial bonding of the particles in the coating. In vivo experiments demonstrated that the composite coating possessed similarly good biocompatibility compared to pure CS coating. The bone-implant contact ratio reached 84.3%±7.4% for GPs/CS coating and 79.6%±9.4% for CS coating after 3 months’ implantation. PMID:26089662

Polymer coating for immobilizing soluble ions in a phosphate ceramic product

DOEpatents

Singh, Dileep; Wagh, Arun S.; Patel, Kartikey D.

2000-01-01

A polymer coating is applied to the surface of a phosphate ceramic composite to effectively immobilize soluble salt anions encapsulated within the phosphate ceramic composite. The polymer coating is made from ceramic materials, including at least one inorganic metal compound, that wet and adhere to the surface structure of the phosphate ceramic composite, thereby isolating the soluble salt anions from the environment and ensuring long-term integrity of the phosphate ceramic composite.

Development of Advanced Environmental Barrier Coatings for SiC/SiC Composites at NASA GRC: Prime-Reliant Design and Durability Perspectives

NASA Technical Reports Server (NTRS)

Zhu, Dongming

2017-01-01

Environmental barrier coatings (EBCs) are considered technologically important because of the critical needs and their ability to effectively protect the turbine hot-section SiC/SiC ceramic matrix composite (CMC) components in harsh engine combustion environments. The development of NASA's advanced environmental barrier coatings have been aimed at significantly improved the coating system temperature capability, stability, erosion-impact, and CMAS resistance for SiC/SiC turbine airfoil and combustors component applications. The NASA environmental barrier coating developments have also emphasized thermo-mechanical creep and fatigue resistance in simulated engine heat flux and environments. Experimental results and models for advanced EBC systems will be presented to help establishing advanced EBC composition design methodologies, performance modeling and life predictions, for achieving prime-reliant, durable environmental coating systems for 2700-3000 F engine component applications. Major technical barriers in developing environmental barrier coating systems and the coating integration with next generation composites having further improved temperature capability, environmental stability, EBC-CMC fatigue-environment system durability will be discussed.

Influence of the powder mixture composition on the deposition coefficient and the properties of NI+B4C CGDS coatings

NASA Astrophysics Data System (ADS)

Kosarev, V. F.; Polukhin, A. A.; Ryashin, N. S.; Fomin, V. M.; Shikalov, V. S.

2017-07-01

The cold gas dynamic spray (CGDS) method used to form composite Ni+B4C coatings from mechanical powder mixture with various content of abrasive components is investigated, and the surface and microstructure of these coatings are considered. An experimental dependence of the deposition coefficient on the abrasive content in the mechanical powder mixture is obtained. The coatings are studied by interference profilometry, optical microscopy, and microindentation methods. The dependence of the bulk and mass B4C content in the sprayed material on the abrasive content in the sprayed powder mixture is obtained. The bulk B4C content in the coating c V ≈ 0.27 is attained. The dependence of the microhardness of composite CGDS coatings on the boron carbide content in them is investigated. The results of this paper demonstrate that the powder mixture composition significantly affects the CGDS coating growth and the properties of these coatings and can be used to control the properties of the CGDS cermet materials.

Carbide coated fibers in graphite-aluminum composites

NASA Technical Reports Server (NTRS)

Imprescia, R. J.; Levinson, L. S.; Reiswig, R. D.; Wallace, T. C.; Williams, J. M.

1975-01-01

The NASA-supported program at the Los Alamos Scientific Laboratory (LASL) to develop carbon fiber-aluminum matrix composites is described. Chemical vapor deposition (CVD) was used to uniformly deposit thin, smooth, continuous coats of TiC on the fibers of graphite tows. Wet chemical coating of fibers, followed by high-temperature treatment, was also used, but showed little promise as an alternative coating method. Strength measurements on CVD coated fiber tows showed that thin carbide coats can add to fiber strength. The ability of aluminum alloys to wet TiC was successfully demonstrated using TiC-coated graphite surfaces. Pressure-infiltration of TiC- and ZrC-coated fiber tows with aluminum alloys was only partially successful. Experiments were performed to evaluate the effectiveness of carbide coats on carbon as barriers to prevent reaction between alluminum alloys and carbon. Initial results indicate that composites of aluminum and carbide-coated graphite are stable for long periods of time at temperatures near the alloy solidus.

Corrosion resistance of Zn-Al layered double hydroxide/poly(lactic acid) composite coating on magnesium alloy AZ31

NASA Astrophysics Data System (ADS)

Zeng, Rong-Chang; Li, Xiao-Ting; Liu, Zhen-Guo; Zhang, Fen; Li, Shuo-Qi; Cui, Hong-Zhi

2015-12-01

A Zn-Al layered double hydroxide (ZnAl-LDH) coating consisted of uniform hexagonal nano-plates was firstly synthesized by co-precipitation and hydrothermal treatment on the AZ31 alloy, and then a poly(lactic acid) (PLA) coating was sealed on the top layer of the ZnAl-LDH coating using vacuum freeze-drying. The characteristics of the ZnAl-LDH/PLA composite coatings were investigated by means of XRD, SEM, FTIR and EDS. The corrosion resistance of the coatings was assessed by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the ZnAl-LDH coating contained a compact inner layer and a porous outer layer, and the PLA coating with a strong adhesion to the porous outer layer can prolong the service life of the ZnAl-LDH coating. The excellent corrosion resistance of this composite coating can be attributable to its barrier function, ion-exchange and self-healing ability.

The Arecibo Pisces-Perseus Survey: An Undergraduate ALFALFA Team Project

NASA Astrophysics Data System (ADS)

O'Donoghue, Aileen A.; Koopmann, Rebecca A.; Haynes, Martha P.; Jones, Michael; Craig, David; Hallenbeck, Gregory L.; Rosenberg, Jessica L.; Venkatesan, Aparna; Undergraduate ALFALFA Team

2016-01-01

The Milky Way's position in an outer filament of Lanieakea affords us a striking view of the Pisces-Perseus Supercluster (PPS) arcing roughly from 22h to 4h and 0° to +50° concentrated between cz = 4,000 km/s and cz = 8,000 km/s as a "wall" parallel to the plane of the sky. It is bounded by voids both between Laniakea and PPS and beyond PPS. Within this box, the 70% ALFALFA survey has detected 4,800 galaxies within cz = 8,000 km/s. Of these, 80% have masses greater than 108 M⊙. At the distance of the PPS, galaxies with MHI ≤ 108 M⊙ are below the ALFALFA detection limit. Thus to further explore this rich diversity of galaxy environments and the adjoining voids, the Undergraduate ALFALFA Team is in the process of using the L-band Wide receiver at Arecibo Observatory for the Arecibo Pisces-Perseus Supercluster Survey (APPSS). We will observe galaxies with 108 M⊙ ≤ MHI ≤ 109 M⊙ chosen from the SDSS DR12 and GALEX catalogs. We are limiting our observations to the PPS ridge in 21h 30m to 3h 15m and 23° to 35°. Since this region lacks SDSS spectroscopy, targets have been selected using photometric criteria derived from SDSS and GALEX observations for galaxies detected by ALFALFA. The results of these observations will allow us to constrain the HI mass function along the PPS ridge. Application of the Tully-Fisher relation will allow a robust measure of the infall velocities of galaxies into the filament. This work has been supported by NSF grant AST-1211005.

A hybrid bioreactor based on insolubilized tyrosinase and laccase catalysis and microfiltration membrane remove pharmaceuticals from wastewater.

PubMed

Ba, Sidy; Haroune, Lounès; Soumano, Lassine; Bellenger, Jean-Phillipe; Jones, J Peter; Cabana, Hubert

2018-06-01

The increasing presence of pharmaceutical products (PPs) and other organic contaminants of emerging concern (CECs) in aquatic systems has become one of the major global environmental contamination concerns. Sewage treatment plants (STPs) are one of the major sources of PPs discharge into natural waters due to the deficiencies of conventional treatment processes to deal with these micropollutants. Numerous new treatment processes and technologies have been investigated for the removals of CECs in wastewaters with more or less success. In the present study, we investigated the efficiency of a hybrid bioreactor (HBR) of a combined crosslinked tyrosinase and laccase aggregates and hollow fiber microfiltration (MF) membrane to remove a mixture of 14 PPs from municipal wastewater at environmentally relevant concentration of 10 μg/L. After a 5-day continuous operation, the HBR achieved complete removal of all tested PPs. Results also highlight that these high performances result from a synergistic action of the MF membrane and the insoluble enzymes. The biocatalyst retained nearly 70% of its initial enzymatic activity over the treatment period. The removal of PPs is unlikely to result from their sole sorption on the membrane. Overall, the results suggest that the HBR is well suited to the biocatalysts (i.e. insolubilized tyrosinase and laccase). The results invite to further investigate how the HBR can be tailored with various types of enzymes and membranes for either specific or non-specific target substrates and to further explore the applicability of this technology for the continuous treatment of wastewater at environmentally relevant concentration of PPs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Fabrication, characterization, and in vitro study of zinc substituted hydroxyapatite/silk fibroin composite coatings on titanium for biomedical applications.

PubMed

Zhong, Zhenyu; Ma, Jun

2017-09-01

Zinc substituted hydroxyapatite/silk fibroin composite coatings were deposited on titanium substrates at room temperature by electrophoretic deposition. Microscopic characterization of the synthesized composite nanoparticles revealed that the particle size ranged 50-200 nm, which increased a little after zinc substitution. The obtained coatings maintained the phase of hydroxyapatite and they could induce fast apatite formation in simulated body fluid, indicating high bone activity. The cell culturing results showed that the biomimetic hydroxyapatite coatings could regulate adhesion, spreading, and proliferation of osteoblastic cells. Furthermore, the biological behavior of the zinc substituted hydroxyapatite coatings was found to be better than the bare titanium without coatings and hydroxyapatite coatings without zinc, increasing MC3T1-E1 cell differentiation in alkaline phosphatase expression.

Development of Advanced Environmental Barrier Coatings for SiC/SiC Ceramic Matrix Composites: Path Toward 2700 F Temperature Capability and Beyond

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Harder, Bryan; Hurst, Janet B.; Good, Brian; Costa, Gustavo; Bhatt, Ramakrishna T.; Fox, Dennis S.

2017-01-01

Advanced environmental barrier coating systems for SiC-SiC Ceramic Matrix Composite (CMC) turbine and combustor hot section components are currently being developed to meet future turbine engine emission and performance goals. One of the significant coating development challenges is to achieve prime-reliant environmental barrier coating systems to meet the future 2700F EBC-CMC temperature stability and environmental durability requirements. This presentation will emphasize recent NASA environmental barrier coating system testing and down-selects, particularly the development path and properties towards 2700-3000F durability goals by using NASA hafnium-hafnia-rare earth-silicon-silicate composition EBC systems for the SiC-SiC CMC turbine component applications. Advanced hafnium-based compositions for enabling next generation EBC and CMCs capabilities towards ultra-high temperature ceramic coating systems will also be briefly mentioned.

Reciprocating sliding wear evaluation of a polymeric/coating tribological system

NASA Astrophysics Data System (ADS)

Braza, J. F.; Furst, R. E.

1993-04-01

Reciprocating screening tests aimed at simulating a control bearing in a contaminated environment to discern the optimum polymeric/coating combination are described. The polymeric/coating systems were compared with the wear of a baseline phenolic impregnated polytetrafluoroethylene (PTFE) polyester woven fabric composite against an uncoated stainless steel substrate. The polymeric composites under consideration include a polyamide-imide (PAI), a polybenzimidazole, and an injection-moldable PEEK. Results indicate that the system of either PEEK or PAI with an E-Ni-PTFE- or TiN-coated substrate produced the best tribological system. These two composites also exhibited a significant improvement over the baseline fabric when tested against the high-velocity oxygen-fuel thermal spray coating. To discern better the optimum polymeric composite/coating system, full-scale testing must be conducted to study system dynamics, vibrations, counterface hardness and roughness, temperature, external environment and application specific conditions.

Investigation of hydrogen evolution activity for the nickel, nickel-molybdenum nickel-graphite composite and nickel-reduced graphene oxide composite coatings

NASA Astrophysics Data System (ADS)

Jinlong, Lv; Tongxiang, Liang; Chen, Wang

2016-03-01

The nickel, nickel-molybdenum alloy, nickel-graphite and nickel-reduced graphene oxide composite coatings were obtained by the electrodeposition technique from a nickel sulfate bath. Nanocrystalline molybdenum, graphite and reduced graphene oxide in nickel coatings promoted hydrogen evolution reaction in 0.5 M H2SO4 solution at room temperature. However, the nickel-reduced graphene oxide composite coating exhibited the highest electrocatalytic activity for the hydrogen evolution reaction in 0.5 M H2SO4 solution at room temperature. A large number of gaps between 'cauliflower' like grains could decrease effective area for hydrogen evolution reaction in slight amorphous nickel-molybdenum alloy. The synergistic effect between nickel and reduced graphene oxide promoted hydrogen evolution, moreover, refined grain in nickel-reduced graphene oxide composite coating and large specific surface of reduced graphene oxide also facilitated hydrogen evolution reaction.

Influence of Silver-hydroxyapatite Nanocomposite Coating on Biofilm Formation of Joint Prosthesis and Its Mechanism.

PubMed

Zhao, L; Ashraf, M A

2015-12-01

The main reason for biomaterial related refractory infections is biofilm formation caused by bacterial adhesion on the surface of materials. Silver-hydroxyapatite (Ag/HA) nanocomposite coating can inhibit the formation of biofilm, but its mechanism is not clear. In order to clarify the mechanism, the amounts of biofilm on the Ag/HA composite coating and HA coating were determined, the release rates of silver nanoparticles in simulated body fluid (SBF) were detected by atomic absorption spectrometry, and the expression values of atlE , fbe , sap , iapB genes of Staphylococcus aureus were studied when they grew on Ag/HA composite coating and HA coating. The amount of the biofilm on the Ag/HA composite coating was significantly less than that on the HA coating, and the bacterial adhesion was decreased. The silver nanoparticles were released continuously in SBF and the release rate decreased gradually with time. The expression values of atlE , fbe and sap were high in the initial stage of adhesion and the expression value of iapB was high in the colonies-gathering stage in the control group, but they were all significantly inhibited in the presence of Ag. These results indicated that the main antibacterial effect of Ag/HA composite coating was achieved by the release of silver nanoparticles. The addition of Ag inhibited the expression of genes related to biofilm formation, which in turn inhibited the formation of biofilms. This provided theoretical support for the clinical application of Ag/HA composite coating.

Gum arabic based composite edible coating on green chillies

NASA Astrophysics Data System (ADS)

Valiathan, Sreejit; Athmaselvi, K. A.

2018-04-01

Green chillies were coated with a composite edible coating composed of gum arabic (5%), glycerol (1%), thyme oil (0.5%) and tween 80 (0.05%) to preserve the freshness and quality of green chillies and thus reduce the cost of preservation. In the present work, the chillies were coated with the composite edible coating using the dipping method with three dipping times (1, 3 and 5 min). The physicochemical parameters of the coated and control chillies stored at room temperature (28±2ºC) were evaluated at regular intervals of storage. There was a significant difference (p≤0.05) in the physicochemical properties between the control chillies and coated chillies with 1, 3 and 5 min dipping times. The coated green chillies showed significantly (p≤0.05) lower weight loss, phenolic acid production, capsaicin production and significantly (p≤0.05) higher retention of ascorbic acid, total chlorophyll content, colour, firmness and better organoleptic properties. The composite edible coating of gum arabic and thyme oil with 3 min dipping was effective in preserving the desirable physico-chemical and organoleptic properties of the green chillies up to 12 days, compared to the uncoated chillies that had a shelf life of 6 days at room temperature.

Corrosion Behavior and Microhardness of Ni-P-SiO2-Al2O3 Nano-composite Coatings on Magnesium Alloy

NASA Astrophysics Data System (ADS)

Sadreddini, S.; Rahemi Ardakani, S.; Rassaee, H.

2017-05-01

In the present work, nano-composites of Ni-P-SiO2-Al2O3 were coated on AZ91HP magnesium alloy. The surface morphology of the nano-composite coating was studied by field emission scanning electron microscopy (FESEM). The amount of SiO2 in the coating was determined by energy-dispersive analysis of x-ray (EDX), and the crystalline structure of the coating was examined by x-ray diffractometer (XRD). All the experiments concerning the corrosion behavior of the coating carried out in 3.5 wt.% NaCl solution and evaluated by electrochemical impedance spectroscopy (EIS) and polarization technique. The results showed that an incorporation of SiO2 and Al2O3 in Ni-P coating at the SiO2 concentration of 10 g/Land 14 g/LAl2O3 led to the lowest corrosion rate ( i corr = 1.3 µA/cm2), the most positive E corr and maximum microhardness (496 VH). Furthermore, Ni-P-SiO2-Al2O3 nano-composite coating possesses less porosity than that in Ni-P coating, resulting in improving corrosion resistance.

Improved irradiation tolerance of reactive gas pulse sputtered TiN coatings with a hybrid architecture of multilayered and compositionally graded structures

NASA Astrophysics Data System (ADS)

Liang, Wei; Yang, Jijun; Zhang, Feifei; Lu, Chenyang; Wang, Lumin; Liao, Jiali; Yang, Yuanyou; Liu, Ning

2018-04-01

This study investigates the improved irradiation tolerance of reactive gas pulse (RGP) sputtered TiN coatings which has hybrid architecture of multilayered and compositionally graded structures. The multilayered RGP-TiN coating is composed of hexagonal close-packed Ti phase and face-centred cubic TiN phase sublayers, where the former sublayer has a compositionally graded structure and the latter one maintains constant stoichiometric atomic ratio of Ti:N. After 100 keV He ion irradiation, the RGP-TiN coating exhibits improved irradiation resistance compared with its single layered (SL) counterpart. The size and density of He bubbles are smaller in the RGP-TiN coating than in the SL-TiN coating. The irradiation-induced surface blistering of the coatings shows a similar tendency. Meanwhile, the irradiation hardening and adhesion strength of the RGP-TiN coatings were not greatly affected by He irradiation. Moreover, the irradiation damage tolerance of the coatings can be well tuned by changing the undulation period number of N2 gas flow rate. Detailed analysis suggested that this improved irradiation tolerance could be related to the combined contribution of the multilayered and compositionally graded structures.

The Effects of Thermophysical Properties and Environmental Conditions on Fire Performance of Intumescent Coatings on Glass Fibre-Reinforced Epoxy Composites

PubMed Central

Kandola, Baljinder K.; Luangtriratana, Piyanuch; Duquesne, Sophie; Bourbigot, Serge

2015-01-01

Intumescent coatings are commonly used as passive fire protection systems for steel structures. The purpose of this work is to explore whether these can also be used effectively on glass fibre-reinforced epoxy (GRE) composites, considering the flammability of the composites compared to non-flammable steel substrate. The thermal barrier and reaction-to-fire properties of three commercial intumescent coatings on GRE composites have been studied using a cone calorimeter. Their thermophysical properties in terms of heating rate and/or temperature dependent char expansion ratios and thermal conductivities have been measured and correlated. It has been suggested that these two parameters can be used to design coatings to protect composite laminates of defined thicknesses for specified periods of time. The durability of the coatings to water absorption, peeling, impact, and flexural loading were also studied. A strong adhesion between all types of coatings and the substrate was observed. Water soaking had a little effect on the fire performance of epoxy based coatings. All types of 1 mm thick coatings on GRE helped in retaining ~90% of the flexural property after 2 min exposure to 50 kW/m2 heat flux whereas the uncoated laminate underwent severe delamination and loss in structural integrity after 1 min. PMID:28793500

In vitro degradation behavior and cytocompatibility of biodegradable AZ31 alloy with PEO/HT composite coating.

PubMed

Tian, Peng; Liu, Xuanyong; Ding, Chuanxian

2015-04-01

Biodegradable magnesium-based implants have attracted much attention recently in orthopedic applications because of their good mechanical properties and biocompatibility. However, their rapid degradation in vivo will not only reduce their mechanical strength, but also induce some side effects, such as local alkalization and gas cavity, which may lead to a failure of the implant. In this work, a hydroxyapatite (HA) layer was prepared on plasma electrolytic oxidization (PEO) coating by hydrothermal treatment (HT) to fabricate a PEO/HT composite coating on biodegradable AZ31 alloy. The in vitro degradation behaviors of all samples were evaluated in simulated body fluid (SBF) and their surface cytocompatibility was also investigated by evaluating the adhesion and proliferation of osteoblast cells (MC3T3-E1). The results showed that the HA layer consisted of a dense inner layer and a needle-like outer layer, which successfully sealed the PEO coating. The in vitro degradation tests showed that the PEO/HT composite coating improved the corrosion resistance of AZ31 alloy in SBF, presenting nearly no severe local alkalization and hydrogen evolution. The lasting corrosion resistance of the PEO/HT composite coating may attribute to the new hydroxyapatite formation during the degradation process. Moreover, compared with AZ31 alloy and PEO coating, PEO/HT composite coating was more suitable for cells adhesion and proliferation, indicating improved surface cytocompatibility. The results show that the PEO/HT composite coating is promising as protective coating on biodegradable magnesium-based implants to enhance their corrosion resistance as well as improve their surface cytocompatibility for orthopedic applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Silica Coating of Nonsilicate Nanoparticles for Resin-Based Composite Materials

PubMed Central

Kaizer, M.R.; Almeida, J.R.; Gonçalves, A.P.R.; Zhang, Y.; Cava, S.S.; Moraes, R.R.

2016-01-01

This study was designed to develop and characterize a silica-coating method for crystalline nonsilicate ceramic nanoparticles (Al2O3, TiO2, and ZrO2). The hypothesis was that the coated nonsilicate nanoparticles would stably reinforce a polymeric matrix due to effective silanation. Silica coating was applied via a sol-gel method, with tetraethyl orthosilicate as a silica precursor, followed by heat treatment. The chemical and microstructural characteristics of the nanopowders were evaluated before and after silica coating through x-ray diffraction, BET (Brunauer-Emmett-Teller), energy-dispersive x-ray spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy analyses. Coated and noncoated nanoparticles were silanated before preparation of hybrid composites, which contained glass microparticles in addition to the nanoparticles. The composites were mechanically tested in 4-point bending mode after aging (10,000 thermal cycles). Results of all chemical and microstructural analyses confirmed the successful obtaining of silica-coated nanoparticles. Two distinct aspects were observed depending on the type of nanoparticle tested: 1) formation of a silica shell on the surface of the particles and 2) nanoparticle clusters embedded into a silica matrix. The aged hybrid composites formulated with the coated nanoparticles showed improved flexural strength (10% to 30% higher) and work of fracture (35% to 40% higher) as compared with composites formulated with noncoated nanoparticles. The tested hypothesis was confirmed: silanated silica-coated nonsilicate nanoparticles yielded stable reinforcement of dimethacrylate polymeric matrix due to effective silanation. The silica-coating method presented here is a versatile and promising novel strategy for the use of crystalline nonsilicate ceramics as a reinforcing phase of polymeric composite biomaterials. PMID:27470069

Bioactive (Si, O, N)/(Ti, O, N)/Ti composite coating on NiTi shape memory alloy for enhanced wear and corrosion performance

NASA Astrophysics Data System (ADS)

Sun, Tao; Xue, Ning; Liu, Chao; Wang, Chao; He, Jin

2015-11-01

In this investigation, (Si, O, N)/(Ti, O, N)/Ti composite coating was synthesized on a NiTi shape memory alloy (SMA) substrate (50.8 at.% Ni) via plasma immersion ion implantation and deposition (PIIID) followed by magnetron sputtering, with the aim of promoting bioactivity and biocompatibility of NiTi SMAs. Nano featured (Si, O, N)/(Ti, O, N)/Ti coating was approximate 0.84 ± 0.05 μm in thickness, and energy dispersive X-ray (EDX) spectroscopy showed that Ni element was depleted from the surface of coated samples. X-ray diffraction (XRD) did not identify the phase composition of the (Si, O, N)/(Ti, O, N)/Ti coating, probably due to its thin thickness and poor crystalline resulting from low-temperature coating processes (<200 °C). X-ray photoelectron spectroscopy (XPS) analyses confirmed that a Ni-free surface was formed and Si element was incorporated into the composite coating via the magnetron sputtering process. Additionally, phase transformation behaviors of uncoated and coated NiTi SMA samples were characterized using differential scanning calorimetry (DSC). Wear and corrosion resistance of uncoated and coated NiTi SMA samples were evaluated using ball-on-disc tests and potentio-dynamic polarization curves, respectively. The (Si, O, N)/(Ti, O, N)/Ti coated NiTi SMA samples showed enhanced wear and corrosion resistance. Furthermore, the (Si, O, N)/(Ti, O, N)/Ti composite coating facilitated apatite formation in simulated body fluid (SBF) and rendered NiTi SMA bioactivity.

Damage tolerant functionally graded materials for advanced wear and friction applications

NASA Astrophysics Data System (ADS)

Prchlik, Lubos

The research work presented in this dissertation focused on processing effects, microstructure development, characterization and performance evaluation of composite and graded coatings used for friction and wear control. The following issues were addressed. (1) Definition of prerequisites for a successful composite and graded coating formation by means of thermal spraying. (2) Improvement of characterization methods available for homogenous thermally sprayed coating and their extension to composite and graded materials. (3) Development of novel characterization methods specifically for FGMs, with a focus on through thickness property measurement by indentation and in-situ curvature techniques. (4) Design of composite materials with improved properties compared to homogenous coatings. (5) Fabrication and performance assessment of FGM with improved wear and impact damage properties. Materials. The materials studied included several material systems relevant to low friction and contact damage tolerant applications: MO-Mo2C, WC-Co cermets as materials commonly used sliding components of industrial machinery and NiCrAlY/8%-Yttria Partially Stabilized Zirconia composites as a potential solution for abradable sections of gas turbines and aircraft engines. In addition, uniform coatings such as molybdenum and Ni5%Al alloy were evaluated as model system to assess the influence of microstructure variation onto the mechanical property and wear response. Methods. The contact response of the materials was investigated through several techniques. These included methods evaluating the relevant intrinsic coating properties such as elastic modulus, residual stress, fracture toughness, scratch resistance and tests measuring the abrasion and friction-sliding behavior. Dry-sand and wet two-body abrasion testing was performed in addition to traditional ball on disc sliding tests. Among all characterization techniques the spherical indentation deserved most attention and enabled to measure elastic-plastic properties of uniform and graded structures. In-situ curvature method used for residual stress and elastic modulus measurement was extended from uniform coatings to coatings with compositional/property gradients. Properties of composite and graded materials were measured using the inverse analysis. Conclusions. The specifics of the elastic-plastic response for thermally sprayed coatings were demonstrated. These included the strain dependence of elastic modulus and damage accumulation related to unloading/reloading loop formation. The measurement of elastic-plastic characteristics of composite coatings revealed the mixing and bonding mechanisms unique for thermally sprayed materials. Microstructural and compositional factors governing the frictional vs. abrasion response of carbide-metallic composite coatings were described. The measurement of abrasion resistance and friction sliding properties demonstrated that grading of cermet and ceramic coatings by adding moderate amount of metallic alloys can enhance elastic-properties radically and have a beneficial effect onto the coating performance.

Hi-Nicalon Fiber-Reinforced Celsian Matrix Composites: Influence of Interface Modification

NASA Technical Reports Server (NTRS)

Bansal, Narottam P.; Eldridge, Jeffrey I.

1998-01-01

Unidirectional celsian matrix composites having 42-45 vol % of uncoated or BN-SIC coated Hi-Nicalon fibers were tested in three-point bend at room temperature. The uncoated fiber-reinforced composites showed catastrophic failure with strength of 210 35 MPa and a flat fracture surface. In contrast, composites reinforced with coated fibers exhibited graceful failure with extensive fiber pullout. Values of first matrix cracking stress and strain were 435 +/- 35 MPa and 0.27 +/- 0.01%, respectively, with ultimate strength as high as 960 MPa. The elastic Young modulus of the uncoated and coated fiber-reinforced composites were 184 +/- 4 GPa and 165 +/- 5 GPa, respectively. Fiber push-through tests and microscopic examination indicated no chemical reaction at the uncoated or coated fiber-matrix interface. The low strength of composite with uncoated fibers is due to degradation of the fiber strength from mechanical damage during processing. Because both the coated- and uncoated-fiber-reinforced composites exhibited weak interfaces, the beneficial effect of the BN-SIC dual layer is primarily the protection of fibers from mechanical damage during processing.

Development of Ferrite-Coated Soft Magnetic Composites: Correlation of Microstructure to Magnetic Properties

NASA Astrophysics Data System (ADS)

Sunday, Katie Jo

Soft magnetic composites (SMCs) comprised of ferrite-coated ferrous powder permit isotropic magnetic flux capabilities, lower core losses, and complex designs through the use of traditional powder metallurgy techniques. Current coating materials and methods are vastly limited by the nonmagnetic properties of organic and some inorganic coatings and their inability to withstand high heat treatments for proper stress relief of core powder after compaction. Ferrite-based coatings are ferrimagnetic, highly resistive, and boast high melting temperatures, thus providing adequate electrical barriers between metallic particles. These insulating layers are necessary for reducing eddy current losses by increasing resistivity in order to improve the overall magnetic efficiency and subsequent frequency range. The goals of this work are to correlate ferrite-coated Fe powder composites microstructure for the coating and core powder to magnetic properties such as permeability, coercivity, and core loss. We first explore the relevant concepts of SMC materials from their composition to processing steps to pertinent properties. This thesis employs a suite of characterization techniques for powder and composite properties. We use X-ray diffraction, scanning electron microscopy, and transmission electron microscopy to provide a complete understanding of the effect of processing conditions on ferrite-coated Fe-based SMCs. Magnetic, mechanical, and electrical properties are then analyzed to correlate microstructural features and determine their effect on such properties. In the second part of this thesis, we present a proof of concept study on Al2O3- and Al2O3- Fe3O4-coated Fe powder composites, illustrating magnetization is highly dependent on ferromagnetic volume. We then expand on previous work to compare an ideal, crystalline state using Fe3O 4-Fe thin film heterostructures to a highly strained state using bulk powder studies. Fe3O4-coated Fe composites are produced via mechanical milling and analyzed for magnetic core loss dependence on particle size, cure temperature, and microstructure of both coating and core powder. We present a significant increase in core loss related to eddy current loss from coating particles sintering and Fe grain growth. Lastly, a more resistive coating material, NiZnCu-ferrite, is applied for improved resistivity, which leads to lower eddy current loss and improved magnetic performance. By highlighting the importance of microstructure and composition on magnetic properties, a closer look at interfacial features and local microstrain are necessary and accomplished in this work. Future developments of ferrite-based SMC coatings are required to transform the use of electromagnetic devices in today's society.

Airborne ultrasonic transducer using polymer-based elastomer with high output-to-weight ratio

NASA Astrophysics Data System (ADS)

Wu, Jiang; Mizuno, Yosuke; Tabaru, Marie; Nakamura, Kentaro

2015-08-01

With the properties of low density, low elastic modulus, and low mechanical loss, poly(phenylene sulfide) (PPS) is a suitable material as the elastomer in an airborne ultrasonic transducer for generating large vibration velocity. In this study, we design and fabricate a transducer composed of a PPS-based longitudinal vibrator and a PPS-based disk of 0.3 mm thickness to obtain high-intensity ultrasound. The rated sound pressure at a distance of 300 mm reached 38.9 Pa (125 dB, 0 dB re. 0.02 mPa) when the frequency and voltage were 58.90 kHz and 20 V. The weight of this transducer is 6.3 g. The ratio of the sound pressure to the weight of the prototype transducer is 1.8 times larger than that of the commercial transducer. The experimental results indicate that PPS is a good substitute for metal as the elastomer for manufacturing airborne ultrasonic transducers with a high output-to-weight ratio.

The Effect of Prospective Payment on Admission and Treatment Policy: Evidence from Inpatient Rehabilitation Facilities

PubMed Central

Sood, Neeraj; Huckfeldt, Peter J; Grabowski, David C; Newhouse, Joseph P; Escarce, José J

2013-01-01

We examine provider responses to the Medicare inpatient rehabilitation facility (IRF) prospective payment system (PPS), which simultaneously reduced marginal reimbursement and increased average reimbursement. IRFs could respond to the PPS by changing the number of patients admitted, admitting different types of patients, or changing the intensity of care. We use Medicare claims data to separately estimate each type of provider response. We also examine changes in patient outcomes and spillover effects on other post-acute care providers. We find that costs of care initially fell following the PPS, which we attribute to changes in treatment decisions rather than the characteristics of patients admitted to IRFs within the diagnostic categories we examine. However, the probability of admission to IRFs increased after the PPS due to the expanded admission policies of providers. We find modest spillover effects in other post-acute settings and negative health impacts for only one of three diagnostic groups studied. PMID:23994598

Peyer’s patches: Organizing B cell responses at the intestinal frontier

PubMed Central

Reboldi, Andrea; Cyster, Jason G

2015-01-01

Summary Secondary lymphoid tissues share the important function of bringing together antigens and rare antigen-specific lymphocytes to foster induction of adaptive immune responses. Peyer’s patches (PPs) are unique compared to other secondary lymphoid tissues in their continual exposure to an enormous diversity of microbiome- and food-derived antigens and in the types of pathogens they encounter. Antigens are delivered to PPs by specialized microfold (M) epithelial cells and they may be captured and presented by resident dendritic cells (DCs). In accord with their state of chronic microbial antigen exposure, PPs exhibit continual germinal center (GC) activity. These GCs contribute to the generation of B cells and plasma cells producing somatically mutated gut antigen-specific IgA antibodies, but have also been suggested to support antigen-nonspecific diversification of the B cell repertoire. Here we review current understanding of how PPs foster B cell encounters with antigen, how they favor isotype switching to the secretory IgA isotype, and how their GC responses may uniquely contribute to mucosal immunity. PMID:27088918

A new timing detector for the CT-PPS project

NASA Astrophysics Data System (ADS)

Arcidiacono, R.; Cms; TOTEM Collaborations

2017-02-01

The CT-PPS detector will be installed close to the beam line on both sides of CMS, 200 m downstream the interaction point. This detector will measure forward scattered protons, allowing detailed studies of diffractive hadron physics and Central Exclusive Production. The main components of the CT-PPS detector are a silicon tracking system and a timing system. In this contribution we present the proposal of an innovative solution for the timing system, based on Ultra-Fast Silicon Detectors (UFSD). UFSD are a novel concept of silicon detectors potentially able to obtain the necessary time resolution (∼20 ps on the proton arrival time). The use of UFSD has also other attractive features as its material budget is small and the pixel geometries can be tailored to the precise physics distribution of protons. UFSD prototypes for CT-PPS have been designed by CNM (Barcelona) and FBK (Trento): we will present the status of the sensor productions and of the low-noise front-end electronics currently under development and test.

Encapsulation and release studies of strawberry polyphenols in biodegradable chitosan nanoformulation.

PubMed

Pulicharla, Rama; Marques, Caroline; Das, Ratul Kumar; Rouissi, Tarek; Brar, Satinder Kaur

2016-07-01

Polyphenols (negative groups) of strawberry extract interacts with positively protonated amino groups of chitosan which helps in maximum encapsulation. This approach can improve the bioavailability and sustained release of phytochemicals having lower bioavailability. The optimum mass ratio of chitosan-tripolyphosphate and polyphenols (PPs) loading was investigated to be 3:1 and 0.5mg/ml of strawberry extract, respectively. Prepared nanoformulation were characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. The formed particles size ranged between 300 and 600nm and polydispersity index (PDI) of≈0.5. The optimized formulation showed encapsulation efficiency of 58.09% at 36.47% of polyphenols loading. Initial burst and continuous release of PPs was observed at pH 7.4 of in vitro release studies. PPs release profile at this pH was found to be non-Fickian analomous diffusion and the release was followed first order kinetics. And at pH 1.4, diffusion-controlled Fickian release of PPs was observed. Copyright © 2016 Elsevier B.V. All rights reserved.

Transoral robotic surgery for parapharyngeal space tumors.

PubMed

O'Malley, Bert W; Quon, Harry; Leonhardt, Fernando D; Chalian, Ara A; Weinstein, Gregory S

2010-01-01

To evaluate the outcomes of patients with parapharyngeal space (PPS) tumors treated with a transoral robotic surgery (TORS) approach. We prospectively enrolled well-defined benign PPS tumors accessible from the oropharynx with no carotid encasement or bone erosion. We designated outcome measures that included technical feasibility of the approach, local tumor control and complication rates. Descriptive statistics were used to summarize the outcome data. With a mean follow-up of 29.9 months (range 12-40 months), a total of 10 patients have been enrolled. TORS was completed in 9 of 10 patients with acceptable operative time and blood loss and no significant complications including hemorrhage, infection, trismus or tumor spillage. Local control has been 100% for 7 patients with pleomorphic adenomas. We confirm the safety and feasibility of the TORS approach for PPS tumors that achieves a high local control and low surgical complication rate. TORS is a viable approach for removing benign tumors and lesions of the PPS. Copyright © 2010 S. Karger AG, Basel.

The influence of a change in medicare reimbursement on the effectiveness of stage III or greater decubitus ulcer home health nursing care.

PubMed

Eaton, Melody K

2005-02-01

This study was designed to describe and evaluate the influence of a change in a Medicare reimbursement on the effectiveness of home health nursing care for stage III or greater decubitus ulcer patients. This health policy originated from the Balanced Budget Act (BBA) of 1997 and took its full effect with initiation of the Prospective Payment System (PPS) on October 1, 2000. A quantitative quasi-experimental design used OASIS data from the state of Virginia to evaluate 555 stage III or greater decubitus ulcer patients, age 65 or older. Comparisons were investigated between pre-PPS, 2000, and post-PPS, 2001, outcomes related to reported ulcer healing, lengths of stay, and discharge disposition. Results demonstrated significant differences for the outcomes studied. In addition, sanitation, ulcer healing, and discharge disposition were linked as predictors for length of stay. Results demonstrated that PPS has affected nursing care effectiveness for stage III or greater decubitus ulcer home health patients.

[Post-polio syndrome. A case report].

PubMed

Bartman, Wojciech; Biernawska, Jolanta; ŁAbuz-Roszak, Beata; Kumor, Klaudiusz; Pierzchała, Krystyna

2004-01-01

Certain acute anterior poliomyelitis survivors express complaints of abnormal fatigue, weakness and muscular atrophy many years after acute onset. These are basic clinical symptoms of so-called post-polio syndrome (PPS). PPS is characterized by a relatively slow, but progressive pathological muscular process, in some cases leading to functional impairment of daily living and professional activity. Breathing, speaking and swallowing impairment are common but not severe medical problems of post-polio patients. Diagnosis is usually based on a typical medical history, electromyographic investigation and exclusion of other diseases presenting similar features. We report a case of PPS in a 49-year-old woman diagnosed in the Neurological Department in Zabrze. Thirty six years after acute anterior poliomyelitis with partial recovery, new symptoms of fatigue, muscular atrophy, exertional dyspnea, walking impairment and joint pain developed. Electromyography revealed features of coexisting spinal denervation and reinnervation in tested muscles. The differential diagnosis excluded other neuromuscular diseases. The patient fulfilled clinical and electromyographic criteria of PPS.

Electrophoretic deposition of gentamicin-loaded bioactive glass/chitosan composite coatings for orthopaedic implants.

PubMed

Pishbin, Fatemehsadat; Mouriño, Viviana; Flor, Sabrina; Kreppel, Stefan; Salih, Vehid; Ryan, Mary P; Boccaccini, Aldo R

2014-06-11

Despite their widespread application, metallic orthopaedic prosthesis failure still occurs because of lack of adequate bone-bonding and the incidence of post-surgery infections. The goal of this research was to develop multifunctional composite chitosan/Bioglass coatings loaded with gentamicin antibiotic as a suitable strategy to improve the surface properties of metallic implants. Electrophoretic deposition (EPD) was applied as a single-step technology to simultaneously deposit the biopolymer, bioactive glass particles, and the antibiotic on stainless steel substrate. The microstructure and composition of the coatings were characterized using SEM/EDX, XRD, FTIR, and TGA/DSC, respectively. The in vitro bioactivity of the coatings was demonstrated by formation of hydroxyapatite after immersion in simulated body fluid (SBF) in a short period of 2 days. High-performance liquid chromatography (HPLC) measurements indicated the release of 40% of the loaded gentamicin in phosphate buffered saline (PBS) within the first 5 days. The developed composite coating supported attachment and proliferation of MG-63 cells up to 10 days. Moreover, disc diffusion test showed improved bactericidal effect of gentamicin-loaded composite coatings against S. aureus compared to control non-gentamicin-loaded coatings.

Fe-C-Si ternary composite coating on CP-titanium and its tribological properties

NASA Astrophysics Data System (ADS)

Maleque, M. A.; Saffina, W.; Ahmed, A. S.; Ali, M. Y.

2017-03-01

This study focused on the development of ternary composite coating through incorporation of Fe-C-Si ternary powder mixtures on CP-Ti substrate and characterizes the microstructure, hardness and wears behavior in presence of Jatropha oil. In this work, the surface of commercial purity titanium (CP-Ti) was modified using a tungsten inert gas (TIG) surface melting technique. The wear behavior of coated CP-titanium was performed using pin-on-disk machine. The results showed that the melt track has dendritic microstructure which was homogenously distributed throughout the melt pool. This Fe-C-Si ternary composite coating enhanced the surface hardness of CP-Ti significantly from 175 HV for the untreated substrate to ∼800 HV for the Fe-C-Si coated CP-Ti due to the formation of intermetallic compounds.. The wear results showed that less wear volume loss was observed on the composite coated CP-Ti in presence of Jatropha-biodiesel compared to uncoated CP-Ti. The achievement of this hard Fe-C-Si composite coating on the surface of CP-Ti can broadened new prospect for many engineering applications that use biodiesel under different tribological variables.

Morphology, Composition, and Bioactivity of Strontium-Doped Brushite Coatings Deposited on Titanium Implants via Electrochemical Deposition

PubMed Central

Liang, Yongqiang; Li, Haoyan; Xu, Jiang; Li, Xin; Qi, Mengchun; Hu, Min

2014-01-01

Surface modification techniques have been applied to generate titanium implant surfaces that promote osseointegration for use in dental applications. In this study, strontium-doped brushite coatings were deposited on titanium by electrochemical deposition. The phase composition of the coating was investigated by energy dispersive X-ray spectroscopy and X-ray diffraction. The surface morphologies of the coatings were studied through scanning electron microscopy, and the cytocompatibility and bioactivity of the strontium-doped brushite coatings were evaluated using cultured osteoblasts. Osteoblast proliferation was enhanced by the addition of strontium, suggesting a possible mechanism by which strontium incorporation in brushite coatings increased bone formation surrounding the implants. Cell growth was also strongly influenced by the composition of the deposited coatings, with a 10% Sr-doped brushite coating inducing the greatest amount of bone formation among the tested materials. PMID:24901526

Pressure pain and isometric strength of neck flexors are related in chronic tension-type headache.

PubMed

Castien, Rene; Blankenstein, Annette; De Hertogh, Willem

2015-01-01

In patients with chronic tension-type headache (CTTH) changes in pressure pain in the cervical region are associated with peripheral or central sensitization. It is hypothesized that an increase of isometric strength of neck flexors would lead to a decrease of pressure pain in CTTH, as an expression of reduced peripheral or central sensitization In this study we aimed to analyze the correlation between change in isometric strength of the neck flexors and change in pressure pain scores (PPS) in patients with CTTH. Comparative analysis of data from previous study. Primary healthcare center. Data from 145 patients with CTTH who underwent a manual therapy program including isometric strength training of the neck flexors were analyzed at 8 and 26 weeks post-treatment. PPS were measured as a total of pain scores on a numeric rating scale (score 0 to 10) on application of a pressure stimulus of 3kg/cm at 8 cervical- and suboccipital muscles. Isometric strength of the neck flexors was measured in seconds. Correlations were computed between changes in PPS and isometric neck flexor strength. Isometric strength of neck flexors scored significantly different compared to baseline measurement (mean 30.0 seconds, sd:25.2), and increased with a mean difference of 17.33 seconds (95%CI: 20.61 to 14.05) at 8 weeks and 19.18 seconds (95%CI: 23.48 to 14.87) at 26 weeks. Similarly, compared to PPS baseline measurement (31.6 points, sd:18.6), mean difference in PPS was significantly decreased at 8 and 26 weeks: -11.3 points (95%CI: -8.77 to -13.83) and -11.15 points (95%CI: -8.31 to -13.99). There is a negative correlation between changes in PPS and changes in isometric strength of neck flexors which is weak at 8 weeks (r = -0.243, P = 0.004) and moderate at 26 weeks (r = -0.318, P < 0.000). Correlational analysis. Decrease in PPS correlates with increases in isometric strength of neck flexors in patients with CTTH in short- and long-term.

Sequential algorithm analysis to facilitate selective biliary access for difficult biliary cannulation in ERCP: a prospective clinical study.

PubMed

Lee, Tae Hoon; Hwang, Soon Oh; Choi, Hyun Jong; Jung, Yunho; Cha, Sang Woo; Chung, Il-Kwun; Moon, Jong Ho; Cho, Young Deok; Park, Sang-Heum; Kim, Sun-Joo

2014-02-17

Numerous clinical trials to improve the success rate of biliary access in difficult biliary cannulation (DBC) during ERCP have been reported. However, standard guidelines or sequential protocol analysis according to different methods are limited in place. We planned to investigate a sequential protocol to facilitate selective biliary access for DBC during ERCP. This prospective clinical study enrolled 711 patients with naïve papillae at a tertiary referral center. If wire-guided cannulation was deemed to have failed due to the DBC criteria, then according to the cannulation algorithm early precut fistulotomy (EPF; cannulation time > 5 min, papillary contacts > 5 times, or hook-nose-shaped papilla), double-guidewire cannulation (DGC; unintentional pancreatic duct cannulation ≥ 3 times), and precut after placement of a pancreatic stent (PPS; if DGC was difficult or failed) were performed sequentially. The main outcome measurements were the technical success, procedure outcomes, and complications. Initially, a total of 140 (19.7%) patients with DBC underwent EPF (n = 71) and DGC (n = 69). Then, in DGC group 36 patients switched to PPS due to difficulty criteria. The successful biliary cannulation rate was 97.1% (136/140; 94.4% [67/71] with EPF, 47.8% [33/69] with DGC, and 100% [36/36] with PPS; P < 0.001). The mean successful cannulation time (standard deviation) was 559.4 (412.8) seconds in EPF, 314.8 (65.2) seconds in DGC, and 706.0 (469.4) seconds in PPS (P < 0.05). The DGC group had a relatively low successful cannulation rate (47.8%) but had a shorter cannulation time compared to the other groups due to early switching to the PPS method in difficult or failed DGC. Post-ERCP pancreatitis developed in 14 (10%) patients (9 mild, 1 moderate), which did not differ significantly among the groups (P = 0.870) or compared with the conventional group (P = 0.125). Based on the sequential protocol analysis, EPF, DGC, and PPS may be safe and feasible for DBC. The use of EPF in selected DBC criteria, DGC in unintentional pancreatic duct cannulations, and PPS in failed or difficult DGC may facilitate successful biliary cannulation.

Physiological and Transcriptional Characterization of Escherichia Coli Strains Lacking Interconversion of Phosphoenolpyruvate and Pyruvate When Glucose and Acetate are Coutilized

PubMed Central

Sabido, Andrea; Sigala, Juan Carlos; Hernández-Chávez, Georgina; Flores, Noemí; Gosset, Guillermo; Bolívar, Francisco

2013-01-01

Phosphoenolpyruvate (PEP) is a precursor involved in the biosynthesis of aromatics and other valuable compounds in Escherichia coli. The PEP:carbohydrate phosphotransferase system (PTS) is the major glucose transport system and the largest PEP consumer. To increase intracellular PEP availability for aromatics production purposes, mutant strains of E. coli JM101 devoid of the ptsHIcrr operon (PB11 strain) have been previously generated. In this derivative, transport and growth rate on glucose decreased significantly. A laboratory evolved strain derived from PB11 that partially recovered its growth capacity on glucose was named PB12. In the present study, we blocked carbon skeletons interchange between PEP and pyruvate (PYR) in these ptsHIcrr− strains by deleting the pykA, pykF, and ppsA genes. The PB11 pykAF− ppsA− strain exhibited no growth on glucose or acetate alone, but it was viable when both substrates were consumed simultaneously. In contrast, the PB12 pykAF− ppsA− strain displayed a low growth rate on glucose or acetate alone, but in the mixture, growth was significantly improved. RT-qPCR expression analysis of PB11 pykAF− ppsA− growing with both carbon sources showed a downregulation of all central metabolic pathways compared with its parental PB11 strain. Under the same conditions, transcription of most of the genes in PB12 pykAF− ppsA− did not change, and few like aceBAK, sfcA, and poxB were overexpressed compared with PB12. We explored the aromatics production capabilities of both ptsHIcrr− pykAF− ppsA− strains and the engineered PB12 pykAF− ppsA− tyrR− pheAev2+/pJLBaroGfbrtktA enhanced the yield of aromatic compounds when coutilizing glucose and acetate compared with the control strain PB12 tyrR− pheAev2+/pJLBaroGfbrtktA. Biotechnol. Bioeng. 2014;111: 1150–1160. © 2013 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc. PMID:24375081

Intravenous immunoglobulin treatment of the post-polio syndrome: sustained effects on quality of life variables and cytokine expression after one year follow up

PubMed Central

2012-01-01

Background Expression of inflammatory cytokines in cerebrospinal fluid (CSF) has led to the hypothesis of intrathecal chronic inflammation to explain the denervation observed in post-polio syndrome (PPS). It has been shown that therapy with intravenous immunoglobulin (IVIG) improves physical performance and dampens down the inflammatory process at 6 months in PPS patients. We here examined the effects of IVIG on cytokine expression and clinical outcome one year after IVIG treatment. Methods From a previous study with 135 PPS patients included, 41 patients were further evaluated before un-blinding for one year (21 placebo and 20 treated with IVIG, Xepol® 50 mg/ml), and were assessed for clinical variables by performing the Short Form-36 survey (SF-36) questionnaire assessment, the 6 minute walk distance test (6MWT) and registering pain level by Visual Analogue Scale (VAS) after IVIG treatment. A separate cohort of 37 PPS patients went through lumbar puncture (LP) at baseline and 20 patients, treated with IVIG, repeated the LP one year later. Thirty patients affected with other neurological diseases (OND) were used as control group. Inflammatory cytokines TNF, TGFβ, IFNγ, IL-23, IL-13 and IL-10 were measured in blood cells and CSF cells with RT-PCR. Results Scores of the physical components of SF-36 were significantly higher at the one year follow up time-point in the IVIG-treated patients when compared to baseline as well as to the control subjects. Pain VAS score and 6MWT improved significantly in the IVIG-treated patients when compared with baseline Relative expression of TNF and IFN-γ in both PBMCs and CSF from PPS patients were increased compared to OND subjects at baseline (p < 0.05). One year after IVIG-treatment a decreased expression of IFN-γ and IL23 was found in CSF of PPS patients, while anti-inflammatory IL-13 was increased (p < 0.05). Conclusions IVIG has effects on relevant QoL variables and inflammatory cytokines up to one year in patients with PPS. This gives a basis for scheduling IVIG in upcoming trials with this therapy. PMID:22776106

Modification of carbon composites by nanoceramic compounds

NASA Astrophysics Data System (ADS)

Stoch, A.; Jastrzebski, W.; Długoń, E.; Stoch, G. J.; Błażewicz, S.; Adamczyk, A.; Tatarzyńska, K.

2005-06-01

Carbon-carbon composites (C/C) exhibit excellent high-temperature mechanical properties but their air oxidation limits their use at temperatures above 500 °C to inert atmosphere. Variety of coatings has been used to protect C/C composites from oxidation. In this work C/C composite substrates were covered with ceramic multilayer coats by electrophoretic deposition from ceramic sols such as silica sol, alumina sol and silica-lumina sol. Sol particles were of nano-sized dimensions. Deposited coats were annealed at 900-1500 °C. Oxidation tests at 600 °C reveal that the best protection of C/C composite against oxidation gives the multilayer coat formed by three or four electrophoretic depositions. The phase composition in the final annealed layers was analyzed by Infrared spectroscopy (FTIR) and by X-ray diffraction analysis (XRD). Morphology and chemical composition was observed using Scanning electron microscopy (SEM) with energy dispersive X-ray microanalysis (EDS).

In situ synthesized TiB-TiN reinforced Ti6Al4V alloy composite coatings: microstructure, tribological and in-vitro biocompatibility.

PubMed

Das, Mitun; Bhattacharya, Kaushik; Dittrick, Stanley A; Mandal, Chitra; Balla, Vamsi Krishna; Sampath Kumar, T S; Bandyopadhyay, Amit; Manna, Indranil

2014-01-01

Wear resistant TiB-TiN reinforced Ti6Al4V alloy composite coatings were deposited on Ti substrate using laser based additive manufacturing technology. Ti6Al4V alloy powder premixed with 5wt% and 15wt% of boron nitride (BN) powder was used to synthesize TiB-TiN reinforcements in situ during laser deposition. Influences of laser power, scanning speed and concentration of BN on the microstructure, mechanical, in vitro tribological and biological properties of the coatings were investigated. Microstructural analysis of the composite coatings showed that the high temperature generated due to laser interaction with Ti6Al4V alloy and BN results in situ formation of TiB and TiN phases. With increasing BN concentration, from 5wt% to 15wt%, the Young's modulus of the composite coatings, measured by nanoindentation, increased from 170±5GPa to 204±14GPa. In vitro tribological tests showed significant increase in the wear resistance with increasing BN concentration. Under identical test conditions TiB-TiN composite coatings with 15wt% BN exhibited an order of magnitude less wear rate than CoCrMo alloy-a common material for articulating surfaces of orthopedic implants. Average top surface hardness of the composite coatings increased from 543±21HV to 877±75HV with increase in the BN concentration. In vitro biocompatibility and flow cytometry study showed that these composite coatings were non-toxic, exhibit similar cell-materials interactions and biocompatibility as that of commercially pure titanium (CP-Ti) samples. In summary, excellent in vitro wear resistance, high stiffness and suitable biocompatibility make these composite coatings as a potential material for load-bearing articulating surfaces towards orthopaedic implants. © 2013 Elsevier Ltd. All rights reserved.

Quality control of the tribological coating PS212

NASA Technical Reports Server (NTRS)

Sliney, Harold E.; Dellacorte, Christopher; Deadmore, Daniel L.

1989-01-01

PS212 is a self-lubricating, composite coating that is applied by the plasma spray process. It is a functional lubricating coating from 25 C (or lower) to 900 C. The coating is prepared from a blend of three different powders with very dissimilar properties. Therefore, the final chemical composition and lubricating effectiveness of the coatings are very sensitive to the process variables used in their preparation. Defined here are the relevant variables. The process and analytical procedures that will result in satisfactory tribological coatings are discussed.

Multilayer ultra-high-temperature ceramic coatings

DOEpatents

Loehman, Ronald E [Albuquerque, NM; Corral, Erica L [Tucson, AZ

2012-03-20

A coated carbon-carbon composite material with multiple ceramic layers to provide oxidation protection from ultra-high-temperatures, where if the carbon-carbon composite material is uninhibited with B.sub.4C particles, then the first layer on the composite material is selected from ZrB.sub.2 and HfB.sub.2, onto which is coated a layer of SiC coated and if the carbon-carbon composite material is inhibited with B.sub.4C particles, then protection can be achieved with a layer of SiC and a layer of either ZrB.sub.2 and HfB.sub.2 in any order.

REFRACTORY COATING FOR GRAPHITE MOLDS

DOEpatents

Stoddard, S.D.

1958-06-24

Refractory coating for graphite molds used in the casting of uranium is described. The coating is an alumino-silicate refractory composition which may be used as a mold surface in solid form or as a coating applied to the graphite mold. The composition consists of a mixture of ball clay, kaolin, alumina cement, alumina, water, sodium silicate, and sodium carbonate.

Sectioning studies of biomimetic collagen-hydroxyapatite coatings on Ti-6Al-4V substrates using focused ion beam

NASA Astrophysics Data System (ADS)

Hu, Changmin; Yu, Le; Wei, Mei

2018-06-01

A biomimetic bone-like collagen-hydroxyapatite (Col-HA) composite coating was formed on a surface-treated Ti-6Al-4V alloy substrate via simultaneous collagen self-assembly and hydroxyapatite nucleation. The coating process has been carried out by immersing sand-blasted, acid-etched and UV irradiated Ti-6Al-4V alloy in type I collagen-containing modified simulated body fluid (m-SBF). The surface morphology and phase composition of the coating were characterized using various techniques. More importantly, dual-beam FIB/SEMs with either gallium ion source (GFIB) or xenon plasma ion source (PFIB) were used to investigate the cross-sectional features of the biomimetic Col-HA composite coating in great details. As a result, the cross-sectional images and thin transmission electron microscopy (TEM) specimens were successfully obtained from the composite coating with no obvious damages or milling ion implantations. Both the cross-sectional SEM and TEM results have confirmed that the Col-HA coating demonstrates a similar microstructure to that of pure HA coating with homogeneously distributed elements across the whole cross section. Both coatings consist of a uniform, crack-free gradient structure with a dense layer adjacent to the interface between the Ti-6Al-4V substrate and the coating facilitating a strong bonding, while a porous structure at the coating surface aiding cell attachment.

Nanostructured hydroxyapatite/poly(lactic-co-glycolic acid) composite coating for controlling magnesium degradation in simulated body fluid.

PubMed

Johnson, Ian; Akari, Khalid; Liu, Huinan

2013-09-20

Biodegradable magnesium (Mg) and its alloys have many attractive properties (e.g. comparable mechanical properties to cortical bone) for orthopedic implant applications, but they degrade too rapidly in the human body to meet clinical requirements. Nanostructured hydroxyapatite (nHA)/poly(lactic-co-glycolic acid) (PLGA) composite coatings provide synergistic properties for controlling degradation of Mg-based substrates and improving bone-implant integration. In this study, nHA/PLGA composites were spin coated onto Mg-based substrates and the results showed that the nHA/PLGA coatings retained nano-scale features with nHA dispersed in PLGA matrix. In comparison with non-coated Mg, the nHA/PLGA composite coated Mg increased the corrosion potential and decreased the corrosion current in revised simulated body fluid (rSBF). After 24 h of immersion in rSBF, increased calcium phosphate (CaP) deposition and formation of Mg-substituted CaP rosettes were observed on the surface of the nHA/PLGA coated Mg, indicating greater bioactivity. In contrast, no significant CaP was deposited on the PLGA coated Mg. Since both PLGA coating and nHA/PLGA coating showed some degree of delamination from Mg-based substrates during extended immersion in rSBF, the coating processing and properties should be further optimized in order to take full advantage of biodegradable Mg and nHA/PLGA nanocomposites for orthopedic applications.

Nanostructured hydroxyapatite/poly(lactic-co-glycolic acid) composite coating for controlling magnesium degradation in simulated body fluid

NASA Astrophysics Data System (ADS)

Johnson, Ian; Akari, Khalid; Liu, Huinan

2013-09-01

Biodegradable magnesium (Mg) and its alloys have many attractive properties (e.g. comparable mechanical properties to cortical bone) for orthopedic implant applications, but they degrade too rapidly in the human body to meet clinical requirements. Nanostructured hydroxyapatite (nHA)/poly(lactic-co-glycolic acid) (PLGA) composite coatings provide synergistic properties for controlling degradation of Mg-based substrates and improving bone-implant integration. In this study, nHA/PLGA composites were spin coated onto Mg-based substrates and the results showed that the nHA/PLGA coatings retained nano-scale features with nHA dispersed in PLGA matrix. In comparison with non-coated Mg, the nHA/PLGA composite coated Mg increased the corrosion potential and decreased the corrosion current in revised simulated body fluid (rSBF). After 24 h of immersion in rSBF, increased calcium phosphate (CaP) deposition and formation of Mg-substituted CaP rosettes were observed on the surface of the nHA/PLGA coated Mg, indicating greater bioactivity. In contrast, no significant CaP was deposited on the PLGA coated Mg. Since both PLGA coating and nHA/PLGA coating showed some degree of delamination from Mg-based substrates during extended immersion in rSBF, the coating processing and properties should be further optimized in order to take full advantage of biodegradable Mg and nHA/PLGA nanocomposites for orthopedic applications.

Obtaining composite Zr-Al-O coating on the surface of zirconium by microplasma oxidation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gubaidulina, Tatiana A., E-mail: goub2002@mail.ru, E-mail: ostk@mail2000ru; Kuzmin, Oleg S., E-mail: goub2002@mail.ru, E-mail: ostk@mail2000ru; Fedorischva, Marina V., E-mail: fmw@ispms.tsc.ru, E-mail: kmp1980@mail.ru

2014-11-14

The paper describes the application of the microplasma oxidation for production of Zr-Al-O composition on the surface of zirconium. Certification of a new-type power supply for depositing oxide ceramic coatings by microplasma oxidation was also carried out. The growth rate of Zr-Al-O coating amounted around 0.2 nm/s, which around 10 times exceeds that for depositing similar coatings using the similar equipment. We have studied the change of surface morphology and the chemical composition of the formed ceramic coating by means of EVO 50 scanning electron microscope and X-ray spectral analysis.

Proteomics Analysis Reveals Distinct Corona Composition on Magnetic Nanoparticles with Different Surface Coatings: Implications for Interactions with Primary Human Macrophages

PubMed Central

Vogt, Carmen; Pernemalm, Maria; Kohonen, Pekka; Laurent, Sophie; Hultenby, Kjell; Vahter, Marie; Lehtiö, Janne; Toprak, Muhammet S.; Fadeel, Bengt

2015-01-01

Superparamagnetic iron oxide nanoparticles (SPIONs) have emerged as promising contrast agents for magnetic resonance imaging. The influence of different surface coatings on the biocompatibility of SPIONs has been addressed, but the potential impact of the so-called corona of adsorbed proteins on the surface of SPIONs on their biological behavior is less well studied. Here, we determined the composition of the plasma protein corona on silica-coated versus dextran-coated SPIONs using mass spectrometry-based proteomics approaches. Notably, gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed distinct protein corona compositions for the two different SPIONs. Relaxivity of silica-coated SPIONs was modulated by the presence of a protein corona. Moreover, the viability of primary human monocyte-derived macrophages was influenced by the protein corona on silica-coated, but not dextran-coated SPIONs, and the protein corona promoted cellular uptake of silica-coated SPIONs, but did not affect internalization of dextran-coated SPIONs. PMID:26444829

Proteomics Analysis Reveals Distinct Corona Composition on Magnetic Nanoparticles with Different Surface Coatings: Implications for Interactions with Primary Human Macrophages.

PubMed

Vogt, Carmen; Pernemalm, Maria; Kohonen, Pekka; Laurent, Sophie; Hultenby, Kjell; Vahter, Marie; Lehtiö, Janne; Toprak, Muhammet S; Fadeel, Bengt

2015-01-01

Superparamagnetic iron oxide nanoparticles (SPIONs) have emerged as promising contrast agents for magnetic resonance imaging. The influence of different surface coatings on the biocompatibility of SPIONs has been addressed, but the potential impact of the so-called corona of adsorbed proteins on the surface of SPIONs on their biological behavior is less well studied. Here, we determined the composition of the plasma protein corona on silica-coated versus dextran-coated SPIONs using mass spectrometry-based proteomics approaches. Notably, gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed distinct protein corona compositions for the two different SPIONs. Relaxivity of silica-coated SPIONs was modulated by the presence of a protein corona. Moreover, the viability of primary human monocyte-derived macrophages was influenced by the protein corona on silica-coated, but not dextran-coated SPIONs, and the protein corona promoted cellular uptake of silica-coated SPIONs, but did not affect internalization of dextran-coated SPIONs.

Hand hygiene compliance rates: Fact or fiction?

PubMed

McLaws, Mary-Louise; Kwok, Yen Lee Angela

2018-05-16

The mandatory national hand hygiene program requires Australian public hospitals to use direct human auditing to establish compliance rates. To establish the magnitude of the Hawthorne effect, we compared direct human audit rates with concurrent automated surveillance rates. A large tertiary Australian teaching hospital previously trialed automated surveillance while simultaneously performing mandatory human audits for 20 minutes daily on a medical and a surgical ward. Subtracting automated surveillance rates from human audit rates provided differences in percentage points (PPs) for each of the 3 quarterly reporting periods for 2014 and 2015. Direct human audit rates for the medical ward were inflated by an average of 55 PPs in 2014 and 64 PPs in 2015, 2.8-3.1 times higher than automated surveillance rates. The rates for the surgical ward were inflated by an average of 32 PPs in 2014 and 31 PPs in 2015, 1.6 times higher than automated surveillance rates. Over the 6 mandatory reporting quarters, human audits collected an average of 255 opportunities, whereas automation collected 578 times more data, averaging 147,308 opportunities per quarter. The magnitude of the Hawthorne effect on direct human auditing was not trivial and produced highly inflated compliance rates. Mandatory compliance necessitates accuracy that only automated surveillance can achieve, whereas daily hand hygiene ambassadors or reminder technology could harness clinicians' ability to hyperrespond to produce habitual compliance. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

Immunome differences between porcine ileal and jejunal Peyer's patches revealed by global transcriptome sequencing of gut-associated lymphoid tissues.

PubMed

Maroilley, T; Berri, M; Lemonnier, G; Esquerré, D; Chevaleyre, C; Mélo, S; Meurens, F; Coville, J L; Leplat, J J; Rau, A; Bed'hom, B; Vincent-Naulleau, S; Mercat, M J; Billon, Y; Lepage, P; Rogel-Gaillard, C; Estellé, J

2018-06-13

The epithelium of the intestinal mucosa and the gut-associated lymphoid tissues (GALT) constitute an essential physical and immunological barrier against pathogens. In order to study the specificities of the GALT transcriptome in pigs, we compared the transcriptome profiles of jejunal and ileal Peyer's patches (PPs), mesenteric lymph nodes (MLNs) and peripheral blood (PB) of four male piglets by RNA-Seq. We identified 1,103 differentially expressed (DE) genes between ileal PPs (IPPs) and jejunal PPs (JPPs), and six times more DE genes between PPs and MLNs. The master regulator genes FOXP3, GATA3, STAT4, TBX21 and RORC were less expressed in IPPs compared to JPPs, whereas the transcription factor BCL6 was found more expressed in IPPs. In comparison between IPPs and JPPs, our analyses revealed predominant differential expression related to the differentiation of T cells into Th1, Th2, Th17 and iTreg in JPPs. Our results were consistent with previous reports regarding a higher T/B cells ratio in JPPs compared to IPPs. We found antisense transcription for respectively 24%, 22% and 14% of the transcripts detected in MLNs, PPs and PB, and significant positive correlations between PB and GALT transcriptomes. Allele-specific expression analyses revealed both shared and tissue-specific cis-genetic control of gene expression.

A unique mid-sequence linker used to multimerize the lipid-phosphatidylserine (PS) binding peptide-peptoid hybrid PPS1.

PubMed

Shukla, Satya Prakash; Manarang, Joseph C; Udugamasooriya, D Gomika

2017-09-08

Ligand multimerizations enhance the binding affinity towards cell surface biomarkers through their avidity effects. Typical linkers connect individual monomeric ligand moieties from one end (e.g., C- or N-terminus of a peptide) and exclusively target protein receptors. The lipid phosphatidylserine (PS) is normally present on the cytoplasmic side of the eukaryotic cell membrane, but in tumors and tumor endothelial cells, this negatively charged PS flips to the outer layer. We recently reported a PS binding peptide-peptoid hybrid (PPS1) that has distinct positively charged and hydrophobic residue-containing regions. The PPS1 monomer is inactive, and upon C-terminal dimerization (PPS1D1), it triggers cytotoxicity. In the current study, a unique series of PPS1 multimeric derivatives were synthesized by switching the linker from the C-terminus to an internal position. The unimportant fourth residue (N-lys) from the C-terminus was utilized to build the linker. The synthesis strategy was developed employing variations of (I) the linker size, (II) the number of positively charged residues, and (III) the number of hydrophobic regions. Cytotoxicity of these new derivatives on HCC4017 lung cancer cells showed that a minimum of two hydrophobic regions was important to retain the activity and that the shortest linker length was optimal for activity. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Use of Medicare services before and after introduction of the prospective payment system.

PubMed

Manton, K G; Woodbury, M A; Vertrees, J C; Stallard, E

1993-08-01

The case mix-adjusted pattern of use of health care services, especially posthospital care, is compared before and after the introduction of Medicare's Prospective Payment System (PPS). The 1982 and 1984 National Long Term Care Surveys (NLTCS) linked to Medicare administrative records 1982-1986 provide health and health service use data for 12-month periods before and after the introduction of PPS. Case-mix differences between pre- and post-periods are controlled by using the Grade of Membership model to identify health groups from the NLTCS data. Differences in timing (e.g., hospital length of stay) were controlled using life table models estimated for each health group, that is, service use patterns pre- and post-PPS are compared within groups. Hospital LOS and admission rates declined post-PPS. Changes in the timing and location of death occurred but, overall, mortality did not increase. Changes in post-acute care service use by elderly, chronically disabled Medicare beneficiaries were observed: home health service use increased overall and among the unmarried disabled population. PPS did not adversely affect quality of care as reflected in mortality or in hospital readmissions. Moreover, the differential use of post-acute care, and changes in hospital LOS by health group, indicate that the system responded, specific to marital status and age, to the severity of needs of chronically disabled persons.

Microstructure and high-temperature oxidation resistance of TiN/Ti3Al intermetallic matrix composite coatings on Ti6Al4V alloy surface by laser cladding

NASA Astrophysics Data System (ADS)

Zhang, Xiaowei; Liu, Hongxi; Wang, Chuanqi; Zeng, Weihua; Jiang, Yehua

2010-11-01

A high-temperature oxidation resistant TiN embedded in Ti3Al intermetallic matrix composite coating was fabricated on titanium alloy Ti6Al4V surface by 6kW transverse-flow CO2 laser apparatus. The composition, morphology and microstructure of the laser clad TiN/Ti3Al intermetallic matrix composite coating were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). In order to evaluate the high-temperature oxidation resistance of the composite coatings and the titanium alloy substrate, isothermal oxidation test was performed in a conventional high-temperature resistance furnace at 600°C and 800°C respectively. The result shows that the laser clad intermetallic composite coating has a rapidly solidified fine microstructure consisting of TiN primary phase (granular-like, flake-like, and dendrites), and uniformly distributed in the Ti3Al matrix. It indicates that a physical and chemical reaction between the Ti powder and AlN powder occurred completely under the laser irradiation. In addition, the microhardness of the TiN/Ti3Al intermetallic matrix composite coating is 844HV0.2, 3.4 times higher than that of the titanium alloy substrate. The high-temperature oxidation resistance test reveals that TiN/Ti3Al intermetallic matrix composite coating results in the better modification of high-temperature oxidation behavior than the titanium substrate. The excellent high-temperature oxidation resistance of the laser cladding layer is attributed to the formation of the reinforced phase TiN and Al2O3, TiO2 hybrid oxide. Therefore, the laser cladding TiN/Ti3Al intermetallic matrix composite coating is anticipated to be a promising oxidation resistance surface modification technique for Ti6Al4V alloy.

Friction and wear behaviors of MoS2/Zr coated HSS in sliding wear and in drilling processes

NASA Astrophysics Data System (ADS)

Deng, Jianxin; Yan, Pei; Wu, Ze

2012-11-01

MoS2 metal composite coatings have been successful used in dry turning, but its suitability for dry drilling has not been yet established. Therefore, it is necessary to study the friction and wear behaviors of MoS2/Zr coated HSS in sliding wear and in drilling processes. In the present study, MoS2/Zr composite coatings are deposited on the surface of W6Mo5Cr4V2 high speed steel(HSS). Microstructural and fundamental properties of these coatings are examined. Ball-on-disc sliding wear tests on the coated discs are carried out, and the drilling performance of the coated drills is tested. Test results show that the MoS2/Zr composite coatings exhibit decreases friction coefficient to that of the uncoated HSS in sliding wear tests. Energy dispersive X-ray(EDX) analysis on the wear surface indicates that there is a transfer layer formed on the counterpart ball during sliding wear processes, which contributes to the decreasing of the friction coefficient between the sliding couple. Drilling tests indicate that the MoS2/Zr coated drills show better cutting performance compared to the uncoated HSS drills, coating delamination and abrasive are found to be the main flank and rake wear mode of the coated drills. The proposed research founds the base of the application of MoS2 metal composite coatings on dry drilling.

Carbon fiber content measurement in composite

NASA Astrophysics Data System (ADS)

Wang, Qiushi

Carbon fiber reinforced polymers (CFRPs) have been widely used in various structural applications in industries such as aerospace and automotive because of their high specific stiffness and specific strength. Their mechanical properties are strongly influenced by the carbon fiber content in the composites. Measurement of the carbon fiber content in CFRPs is essential for product quality control and process optimization. In this work, a novel carbonization-in-nitrogen method (CIN) is developed to characterize the fiber content in carbon fiber reinforced thermoset and thermoplastic composites. In this method, a carbon fiber composite sample is carbonized in a nitrogen environment at elevated temperatures, alongside a neat resin sample. The carbon fibers are protected from oxidization while the resin (the neat resin and the resin matrix in the composite sample) is carbonized under the nitrogen environment. The residue of the carbonized neat resin sample is used to calibrate the resin carbonization rate and calculate the amount of the resin matrix in the composite sample. The new method has been validated on several thermoset and thermoplastic resin systems and found to yield an accurate measurement of fiber content in carbon fiber polymer composites. In order to further understand the thermal degradation behavior of the high temperature thermoplastic polymer during the carbonization process, the mechanism and the kinetic model of thermal degradation behavior of carbon fiber reinforced poly (phenylene sulfide) (CPPS) are studied using thermogravimetry analysis (TGA). The CPPS is subjected to TGA in an air and nitrogen atmosphere at heating rates from 5 to 40°C min--1. The TGA curves obtained in air are different from those in nitrogen. This demonstrates that weight loss occurs in a single stage in nitrogen but in two stages in air. To elucidate this difference, thermal decomposition kinetics is analyzed by applying the Kissinger, Flynn-Wall-Ozawa, Coat-Redfern and Malek methods. The activation energy (Ea) of the solid-state process is determined to be 202 kJ mol--1 in an oxidative atmosphere using Kissinger's method, which is 10-15 kJ mol--1 more than the results calculated in a nitrogen atmosphere. The value of the activation energy obtained using Ozawa-Flynn methods is in agreement with that using the Kissinger method. Different degradation mechanisms are used to compare with this value. Based on the analytical result, the actual thermal degradation mechanism of the CPPS is a Dn deceleration type. The carbonization temperature range of the CPPS is the same as pure PPS resin.

Dielectric properties of Ni-coated BaTiO/sub 3-/PMMA composite.

PubMed

Park, Jung Min; Lee, Hee Young; Kim, Jeong-Joo; Park, Eun Tae; Chung, Yul-Kyo

2008-05-01

Dielectric properties of Ni-coated BaTiO(3)-PMMA (polymethyl methacrylate) composite were studied from an embedded capacitor application viewpoint. Volume loading of up to 50% was attempted, and the results were compared with uncoated BaTiO(3)-PMMA composite. Ni-coating on BaTiO(3) powder was found to greatly improve the dielectric properties of the composite, especially the dielectric constant value. K values of about 100 with temperature-stable X7E characteristics were realized.

Method of making gas diffusion layers for electrochemical cells

DOEpatents

Frisk, Joseph William; Boand, Wayne Meredith; Larson, James Michael

2002-01-01

A method is provided for making a gas diffusion layer for an electrochemical cell comprising the steps of: a) combining carbon particles and one or more surfactants in a typically aqueous vehicle to make a preliminary composition, typically by high shear mixing; b) adding one or more highly fluorinated polymers to said preliminary composition by low shear mixing to make a coating composition; and c) applying the coating composition to an electrically conductive porous substrate, typically by a low shear coating method.

Organic Coatings to Improve the Storageability and Safety of Pyrotechnic Compositions.

DTIC Science & Technology

1987-11-01

TERMS (CONTINUE ON REVERSE IF NECESSARY AND IDENTIFY BY BLOCK NUMBER) FIELD GROUP sue-oRouP Organic coatings Pyrotechnic compositions Magnesium coatings...Storageability Hydrogen gassing \\ ABSTRACT (CONTINUE ON REVERSE IF NECESSARY AND IDENTIFY BY BLOCK NUMBER) study was conducted to find organic...composition 52% KC10 3, 31% S2S31 17% dextrin Impact = (14 cm Coated with 5% Elvax-360 Impact = 16 cm in Ln cn- -T 01 LA 1C) -l4 -t, 0 14-1 0 toJ 0 0 110

(YIP-10) Enabling Dynamic Oxidation Mechanisms in Reverse Infiltrated Ultra-High Temperature Ceramic Coated C-C Composites for Application in Hypersonics

DTIC Science & Technology

2013-08-09

of Hf,Zr oxychloride hydrates, triethyl borate , and phenolic resin to form precipitate free sols that turn into stable gels with no catalyst addition...minutes, shows the glass -ceramic coating (that formed a shell upon cooling) was generated from within the UHTC filled C-C composite. Notice, in Figure...generation of the coating during high temperature exposure to oxygen. The formation of a ZrO2-SiO2 glass -ceramic coating on the C-C composite is believed to

Wear studies on plasma-sprayed Al2O3 and 8mole% of Yttrium-stabilized ZrO2 composite coating on biomedical Ti-6Al-4V alloy for orthopedic joint application

PubMed Central

Ganapathy, Perumal; Manivasagam, Geetha; Rajamanickam, Asokamani; Natarajan, Alagumurthi

2015-01-01

This paper presents the wear characteristics of the composite ceramic coating made with Al2O3-40wt%8YSZ on the biomedical grade Ti-6Al-4V alloy (grade 5) used for total joint prosthetic components, with the aim of improving their tribological behavior. The coatings were deposited using a plasma spraying technique, and optimization of plasma parameters was performed using response surface methodology to obtain dense coating. The tribological behaviors of the coated and uncoated substrates were evaluated using a ball-on-plate sliding wear tester at 37°C in simulated body-fluid conditions. The microstructure of both the titanium alloy and coated specimen were examined using an optical microscope and scanning electron microscope. The hardness of the plasma-sprayed alumina–zirconia composite coatings was 2.5 times higher than that of the Ti-6Al-4V alloy, while the wear rate of Ti-6Al-4V alloy was 253 times higher than that of the composite-coated Ti-6Al-4V alloy. The superior wear resistance of the alumina–zirconia coated alloy is attributed to its enhanced hardness and intersplat bonding strength. Wear-track examination showed that the predominant wear mechanism of Ti-6Al-4V alloy was abrasive and adhesive wear, whereas, in the case of alumina–zirconia composite coated alloy, the wear was dominated by microchipping and microcracking. PMID:26491323

Influence of Silver-hydroxyapatite Nanocomposite Coating on Biofilm Formation of Joint Prosthesis and Its Mechanism

PubMed Central

Zhao, L; Ashraf, MA

2015-01-01

ABSTRACT Background: The main reason for biomaterial related refractory infections is biofilm formation caused by bacterial adhesion on the surface of materials. Silver-hydroxyapatite (Ag/HA) nanocomposite coating can inhibit the formation of biofilm, but its mechanism is not clear. Material and Method: In order to clarify the mechanism, the amounts of biofilm on the Ag/HA composite coating and HA coating were determined, the release rates of silver nanoparticles in simulated body fluid (SBF) were detected by atomic absorption spectrometry, and the expression values of atlE, fbe, sap, iapB genes of Staphylococcus aureus were studied when they grew on Ag/HA composite coating and HA coating. Results: The amount of the biofilm on the Ag/HA composite coating was significantly less than that on the HA coating, and the bacterial adhesion was decreased. The silver nanoparticles were released continuously in SBF and the release rate decreased gradually with time. The expression values of atlE, fbe and sap were high in the initial stage of adhesion and the expression value of iapB was high in the colonies-gathering stage in the control group, but they were all significantly inhibited in the presence of Ag. Conclusion: These results indicated that the main antibacterial effect of Ag/HA composite coating was achieved by the release of silver nanoparticles. The addition of Ag inhibited the expression of genes related to biofilm formation, which in turn inhibited the formation of biofilms. This provided theoretical support for the clinical application of Ag/HA composite coating. PMID:27400164

Tribological Properties of Ti(Al,O)/Al2O3 Composite Coating by Thermal Spraying

NASA Astrophysics Data System (ADS)

Salman, Asma; Gabbitas, Brian; Cao, Peng; Zhang, Deliang

The use of thermal spray coatings provides protection to the surfaces operating in severe environments. The main goal of the current work is to investigate the possibility of using a high velocity air fuel (HVAF) thermally sprayed wear resistant Ti(Al,O)/Al2O3 coating on tool steel (H13) which is used for making dies for aluminium high pressure die casting and dummy blocks aluminium extrusion. A feedstock of Ti(Al,O)/Al2O3 composite powder was produced from a mixture of Al and TiO2 powders by high energy mechanical milling, followed by a thermal reaction process. The feedstock was then thermally sprayed using a high velocity air-fuel (HVAF) technique onto H13 steel substrates to produce a composite coating. The present study describes and compares the tribological properties such as friction and sliding wear rate of the coating both at room and high temperature (700°C). The wear resistance of the coating was investigated by a tribometer using a spherical ended alumina pin as a counter body under dry and lubricating conditions. The results showed that composite coating has lower wear rate at high temperature than at room temperature without using lubricant. The composite coating was characterized using scanning electron microscopy (SEM), optical microscopy and X-ray diffractometry (XRD). This paper reports the experimental observations and discusses the wear resistance performance of the coatings at room and high temperatures.

Microstructure and mechanical properties of plasma sprayed HA/YSZ/Ti-6Al-4V composite coatings.

PubMed

Khor, K A; Gu, Y W; Pan, D; Cheang, P

2004-08-01

Plasma sprayed hydroxyapatite (HA) coatings on titanium alloy substrate have been used extensively due to their excellent biocompatibility and osteoconductivity. However, the erratic bond strength between HA and Ti alloy has raised concern over the long-term reliability of the implant. In this paper, HA/yttria stabilized zirconia (YSZ)/Ti-6Al-4V composite coatings that possess superior mechanical properties to conventional plasma sprayed HA coatings were developed. Ti-6Al-4V powders coated with fine YSZ and HA particles were prepared through a unique ceramic slurry mixing method. The so-formed composite powder was employed as feedstock for plasma spraying of the HA/YSZ/Ti-6Al-4V coatings. The influence of net plasma energy, plasma spray standoff distance, and post-spray heat treatment on microstructure, phase composition and mechanical properties were investigated. Results showed that coatings prepared with the optimum plasma sprayed condition showed a well-defined splat structure. HA/YSZ/Ti-6Al-4V solid solution was formed during plasma spraying which was beneficial for the improvement of mechanical properties. There was no evidence of Ti oxidation from the successful processing of YSZ and HA coated Ti-6Al-4V composite powders. Small amount of CaO apart from HA, ZrO(2) and Ti was present in the composite coatings. The microhardness, Young's modulus, fracture toughness, and bond strength increased significantly with the addition of YSZ. Post-spray heat treatment at 600 degrees C and 700 degrees C for up to 12h was found to further improve the mechanical properties of coatings. After the post-spray heat treatment, 17.6% increment in Young's modulus (E) and 16.3% increment in Vicker's hardness were achieved. The strengthening mechanisms of HA/YSZ/Ti-6Al-4V composite coatings were related to the dispersion strengthening by homogeneous distribution of YSZ particles in the matrix, the good mechanical properties of Ti-6Al-4V and the formation of solid solution among HA, Ti alloy and YSZ components.

How To Become a Great Public Space.

ERIC Educational Resources Information Center

Block, Marylaine

2003-01-01

Presents interviews with Fred Kent, founder of the Project for Public Spaces (PPS) and Phil Myrick, PPS's assistant vice president, about transforming libraries into desirable public spaces. Discusses qualities people value in public spaces; great library buildings and what they are doing right; the first thing library directors should do when…

ATRAZINE-INDUCED REPRODUCTIVE TRACT ALTERATIONS AFTER TRANSPLACENTAL AND LACTATIONAL EXPOSURE IN LONG-EVANS RAT PUPS

EPA Science Inventory

Studies have shown that early postnatal exposure to the common herbicide atrazine (ATR) will delay preputial separation (PPS) in Wistar rats and increase incidence of prostate inflammation in adults. To evaluate ATR exposure parameters required for pubertal delays (PPS), we used...

Applications of laser ultrasound NDT methods on composite structures in aerospace industry

NASA Astrophysics Data System (ADS)

Kalms, Michael; Focke, Oliver; v. Kopylow, Christoph

2008-09-01

Composite materials are used more and more in aircraft production. Main composite types are Carbon Fiber Reinforced Plastics (CFRP), Glass Fiber Reinforced Plastics (GFRP) and metal-aluminium laminates (e. g. Glass Fiber Aluminium Reinforced GLARE©). Typical parts made of CFRP material are flaps, vertical and horizontal tail planes, center wing boxes, rear pressure bulkheads, ribs and stringers. These composite parts require adequate nondestructive testing (NDT) methods. Flaws to be detected are delaminations and debondings, porosity and foreign body inclusion. Manual ultrasonic testing with single element transducers is still the most applied method for composite parts with small and medium size. The extension of the conventional ultrasound technique for nondestructive testing with the laser ultrasound method brings new possibilities into the production processes for example the inspection of complex CFRP-components and the possibilities of online observation under remote control. In this paper we describe the principle of laser ultrasound with respect to the demands of nondestructive testing especially of small complex CFRP and C/PPS parts. We report applications of laser-based ultrasound options with generated types of guided and bulk waves on modern aircraft materials.

Evaluation of selected thermal control coatings for long-life space structures

NASA Technical Reports Server (NTRS)

Teichman, Louis A.; Slemp, Wayne S.; Witte, William G., Jr.

1992-01-01

Graphite-reinforced resin matrix composites are being considered for spacecraft structural applications because of their light weight, high stiffness, and lower thermal expansion. Thin protective coatings with stable optical properties and the proper ratio of solar absorption (alpha sub s) to thermal emittance (epsilon) minimize orbital thermal extremes and protect these materials against space environment degradation. Sputtered coatings applied directly to graphite/epoxy composite surfaces and anodized coatings applied to thin aluminum foil were studied for use both as an atomic oxygen barrier and as thermal control coatings. Additional effort was made to develop nickel-based coatings which could be applied directly to composites. These coating systems were selected because their inherent tenacity made them potentially more reliable than commercial white paints for long-life space missions. Results indicate that anodized aluminum foil coatings are suitable for tubular and flat composite structures on large platforms in low Earth orbit. Anodized foil provides protection against some elements of the natural space environment (atomic oxygen, ultraviolet, and particulate radiation) and offers a broad range of tailored alpha sub s/epsilon. The foil is readily available and can be produced in large quantities, while the anodizing process is a routine commercial technique.

LaCrO3/CuFe2O4 Composite-Coated Crofer 22 APU Stainless Steel Interconnect of Solid Oxide Fuel Cells

NASA Astrophysics Data System (ADS)

Hosseini, Seyedeh Narjes; Enayati, Mohammad Hossein; Karimzadeh, Fathallah; Dayaghi, Amir Masoud

2017-07-01

Rapidly rising contact resistance and cathode Cr poisoning are the major problems associated with unavoidable chromia scale growth on ferritic stainless steel (FSS) interconnects of solid oxide fuel cells. This work investigates the performance of the novel screen-printed composite coatings consisting of dispersed conductive LaCrO3 particles in a CuFe2O4 spinel matrix for Crofer 22 APU FSS, with emphasis on the oxidation behavior and electrical conductivity of these coatings. The results show that the presence of protective spinel coating, accompanied by the effective role of LaCrO3 particle incorporation, prevents the Cr2O3 subscale growth as well as chromium migration into the coating surface at the end of 400 hours of oxidation at 1073 K (800 °C) in air. In addition, the composite coatings decreased the area specific resistance (ASR) from 51.7 and 13.8 mΩ cm2 for uncoated and spinel-coated samples, respectively, to a maximum of 7.7 mΩ cm2 for composite-coated samples after 400 hours of oxidation.

Microstructure and Wear Resistance of Composite Coating by Laser Cladding Al/TiN on the Ti-6Al-4V Substrate

NASA Astrophysics Data System (ADS)

Zhang, H. X.; Yu, H. J.; Chen, C. Z.

2015-05-01

The composite coatings were fabricated by laser cladding Al/TiN pre-placed powders on Ti-6Al-4V substrate for enhancing wear resistance and hardness of the substrate. The composite coatings were analyzed by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The sliding wear tests were performed by MM200 wear test machine. The hardness of the coatings was tested by HV-1000 hardness tester. After laser cladding, it was found that there was a good metallurgical bond between the coating and the substrate. The composite coatings were mainly composed of the matrix of β-Ti (Al) and the reinforcements of titanium nitride (TiN), Ti3Al, TiAl and Al3Ti. The hardness and wear resistance of the coatings on four samples were greatly improved, among which sample 4 exhibited the highest hardness and best wear resistance. The hardness of the coating on sample 4 was approximately 2.5 times of the Ti-6Al-4V substrate. And the wear resistance of sample 4 was four times of the substrate.

Theoretical and experimental studies on silica-coated carbon spheres composites

NASA Astrophysics Data System (ADS)

Guo, Xingmei; Liu, Haixing; Shen, Yinghua; Niu, Mei; Yang, Yongzhen; Liu, Xuguang

2013-10-01

In order to prepare carbon-based photonic crystals, first of all, theoretical modeling calculation was used to predict the bandgap characteristics of silica-coated carbon spheres. Then, silica-coated carbon spheres composites were synthesized using tetraethyl orthosilicate as precursor of silica by a sol-gel method combined with Stöber method. Effect of reaction conditions on surface coating of carbon spheres with silica, including the pH, the amount of precursor and reaction time, was emphasized. The morphology and structure of the composites and the effect coating of carbon spheres with silica were characterized by field-emission scanning electron microscopy, high resolution transmission electron microscopy and Fourier-transform infrared spectrometry. The coating ratio of silica was investigated by thermogravimetry. The results show that pH value played an important role in coating reaction, the dosage of the precursor and reaction time had significant effect on coating layer thickness, that is, coating ratio. Carbon spheres coated with silica had good dispersibility and dispersion stability in water and ethanol, which is preconditions of reactivity of carbon spheres in liquid phase and lays the basis for the application of carbon spheres.

Preparing and Study the effects of Composite Coatings in Protection of Oil Pipes from the Risk of Corrosion that resulting from Associated water with Petroleum Products

NASA Astrophysics Data System (ADS)

– Sarraf, A. R. Al; Yaseen, M. A.

2018-05-01

In order to inhibit the metallic corrosion in the oil pipelines,the protection method with composite coating of unsaturated polyester and reinforced by Caolin at weight percentage (20%) was studied. Where, the work samples were classified into two groups according to internal composite coatings layers for all groups of these samples. The first group is nitrocellulose coating reinforced by nano and micro powder of Mgo, the second group is sodium silicate coating reinforced by nano powder of Mgo. The following weight percentages (0%, 1%, 3% and 5%) were adopted as reinforcement ratios for nano powders, as well as the weight percentages (0%, 3%, 5% and 7%) as reinforcement ratios for micro powders Tribology properties and Electrochemical Corrosion Resistance by Polarization method (Tafel) and Adhesion Strength were studied. The results showed an improvement in the corrosion resistance of protected steel by coatings compare with uncoated steel, as well as improvement in mechanical properties and adhesion strength of composite coatings.

Study of the structure and chemical composition of the protective coating of a fist stage gas turbine blade after regenerative heat treatment

NASA Astrophysics Data System (ADS)

Davidov, D. I.; Kazantseva, N. V.; Vinogradova, N. I.; Ezhov, I. V.

2017-12-01

Investigation of the structure and chemical composition of the protective coating of the first stage IN738 gas turbine blade after standard regenerative heat treatment was done. It was found the degradation of microstructure and chemical composition of both the blade feather and its protective coating. Redistribution of the chemical elements decreasing the corrosion resistance was observed inside the protective coating. Cracks on the boundary between the blade feather and the protective coating were found by scanning electron microscopy. The carbide transformation and sigma phase were found in the structure of the blade feather. Based upon the structural and chemical composition studies, it is concluded that the standard regenerative heat treatment of the IN738 operative gas turbine blade does not provide full structure regeneration.

Preparation and thermal shock resistance of high emissivity molybdenum disilicide- aluminoborosilicate glass hybrid coating on fiber reinforced aerogel composite

NASA Astrophysics Data System (ADS)

Shao, Gaofeng; Lu, Yucao; Wu, Xiaodong; Wu, Jun; Cui, Sheng; Jiao, Jian; Shen, Xiaodong

2017-09-01

To develop a flexible reusable surface insulation for thermal protection system, MoSi2-aluminoborosilicate glass hybrid coatings have been prepared on Al2O3 fiber reinforced Al2O3-SiO2 aerogel composite by slurry dipping and rapid sintering method. The effect of MoSi2 content on radiative property and thermal shock behavior was investigated. The total emissivity values of all the coatings exceeded 0.85 in the wavelength of 0.8-2.5 μm. The M10 and M50 coatings were up to 0.9, which was due to the highest amorphous glass content of the M10 coating and the largest surface roughness of the M50 coating. The M30 coated composite showed the best thermal shock resistance with only 0.023% weight loss after 20 thermal shock cycles between 1473 K and room temperature, which was attributed to the similar thermal expansion coefficients between the coating and the substrate and the appropriate viscosity of aluminoborosilicate glass at 1473 K. The cracks resulted from CTE mismatch stress with different sizes formed and grew on the surface of M10, M40 and M50 coated samples, leading to the failure of the composites.

Contact Behavior of Composite CrTiSiN Coated Dies in Compressing of Mg Alloy Sheets under High Pressure

PubMed Central

Yang, T.S.; Yao, S.H.; Chang, Y.Y.; Deng, J.H.

2018-01-01

Hard coatings have been adopted in cutting and forming applications for nearly two decades. The major purpose of using hard coatings is to reduce the friction coefficient between contact surfaces, to increase strength, toughness and anti-wear performance of working tools and molds, and then to obtain a smooth work surface and an increase in service life of tools and molds. In this report, we deposited a composite CrTiSiN hard coating, and a traditional single-layered TiAlN coating as a reference. Then, the coatings were comparatively studied by a series of tests. A field emission SEM was used to characterize the microstructure. Hardness was measured using a nano-indentation tester. Adhesion of coatings was evaluated using a Rockwell C hardness indentation tester. A pin-on-disk wear tester with WC balls as sliding counterparts was used to determine the wear properties. A self-designed compression and friction tester, by combining a Universal Testing Machine and a wear tester, was used to evaluate the contact behavior of composite CrTiSiN coated dies in compressing of Mg alloy sheets under high pressure. The results indicated that the hardness of composite CrTiSiN coating was lower than that of the TiAlN coating. However, the CrTiSiN coating showed better anti-wear performance. The CrTiSiN coated dies achieved smooth surfaces on the Mg alloy sheet in the compressing test and lower friction coefficient in the friction test, as compared with the TiAlN coating. PMID:29316687

Contact Behavior of Composite CrTiSiN Coated Dies in Compressing of Mg Alloy Sheets under High Pressure.

PubMed

Yang, T S; Yao, S H; Chang, Y Y; Deng, J H

2018-01-08

Hard coatings have been adopted in cutting and forming applications for nearly two decades. The major purpose of using hard coatings is to reduce the friction coefficient between contact surfaces, to increase strength, toughness and anti-wear performance of working tools and molds, and then to obtain a smooth work surface and an increase in service life of tools and molds. In this report, we deposited a composite CrTiSiN hard coating, and a traditional single-layered TiAlN coating as a reference. Then, the coatings were comparatively studied by a series of tests. A field emission SEM was used to characterize the microstructure. Hardness was measured using a nano-indentation tester. Adhesion of coatings was evaluated using a Rockwell C hardness indentation tester. A pin-on-disk wear tester with WC balls as sliding counterparts was used to determine the wear properties. A self-designed compression and friction tester, by combining a Universal Testing Machine and a wear tester, was used to evaluate the contact behavior of composite CrTiSiN coated dies in compressing of Mg alloy sheets under high pressure. The results indicated that the hardness of composite CrTiSiN coating was lower than that of the TiAlN coating. However, the CrTiSiN coating showed better anti-wear performance. The CrTiSiN coated dies achieved smooth surfaces on the Mg alloy sheet in the compressing test and lower friction coefficient in the friction test, as compared with the TiAlN coating.

Composite materials flown on the Long Duration Exposure Facility

NASA Technical Reports Server (NTRS)

George, Pete E.; Dursch, Harry W.; Pippin, H. Gary

1995-01-01

Organic composite test specimens were flown on several LDEF experiments. Both bare and coated composites were flown. Atomic oxygen eroded bare composite material, with the resins being recessed at a greater rate than the fibers. Selected coating techniques protected the composite substrate in each case. Tensile and optical properties are reported for numerous specimens. Fiberglass and metal matrix composites were also flown.

Formation of selenide, sulfide or mixed selenide-sulfide films on metal or metal coated substrates

DOEpatents

Eser, Erten; Fields, Shannon

2012-05-01

A process and composition for preventing cracking in composite structures comprising a metal coated substrate and a selenide, sulfide or mixed selenide sulfide film. Specifically, cracking is prevented in the coating of molybdenum coated substrates upon which a copper, indium-gallium diselenide (CIGS) film is deposited. Cracking is inhibited by adding a Se passivating amount of oxygen to the Mo and limiting the amount of Se deposited on the Mo coating.

Method for producing nanowire-polymer composite electrodes

DOEpatents

Pei, Qibing; Yu, Zhibin

2017-11-21

A method for producing flexible, nanoparticle-polymer composite electrodes is described. Conductive nanoparticles, preferably metal nanowires or nanotubes, are deposited on a smooth surface of a platform to produce a porous conductive layer. A second application of conductive nanoparticles or a mixture of nanoparticles can also be deposited to form a porous conductive layer. The conductive layer is then coated with at least one coating of monomers that is polymerized to form a conductive layer-polymer composite film. Optionally, a protective coating can be applied to the top of the composite film. In one embodiment, the monomer coating includes light transducing particles to reduce the total internal reflection of light through the composite film or pigments that absorb light at one wavelength and re-emit light at a longer wavelength. The resulting composite film has an active side that is smooth with surface height variations of 100 nm or less.

Development of high performance electroless Ni-P-HNT composite coatings

NASA Astrophysics Data System (ADS)

Ranganatha, S.; Venkatesha, T. V.; Vathsala, K.

2012-12-01

Halloysite nanotubes (HNTs) of the dimension 50 nm × 1-3 μm (diameter × length) are utililized to fabricate the alloy composite by employing electroless/autocatalytic deposition technique. Electroless Ni-P-HNT binary alloy composite coatings are prepared successfully on low carbon steel. These nanotubes were made to get inserted/incorporated into nickel matrix and corresponding composites are examined for their electrochemical, mechanical and tribological performances and compared with that of plain Ni-P. The coatings were characterized using scanning electron microscopy (SEM) and Energy dispersive X-ray analysis (EDX) techniques to analyze surface nature and composition correspondingly. Small amount of incorporated HNTs made Ni-P deposits appreciable enhancement and betterment in corrosion resistance, hardness and friction resistance. This drastic improvement in the properties reflects the effect of addition of HNTs into Ni-P matrix leading to the development of high performance Ni-P-HNT composite coatings.

Modified carbon fibers to improve composite properties. [sizing fibers for reduced electrical conductivity and adhesion during combustion

NASA Technical Reports Server (NTRS)

Shepler, R. E.

1979-01-01

Thin coatings, 5 to 10 wt. percent, were applied to PAN-based carbon fibers. These coatings were intended to make the carbon fibers less electrically conductive or to cause fibers to stick together when a carbon fiber/epoxy composite burned. The effectiveness of the coatings in these regards was evaluated in burn tests with a test rig designed to simulate burning, impact and wind conditions which might release carbon fibers. The effect of the coatings on fiber and composite properties and handling was also investigated. Attempts at sizing carbon fibers with silicon dioxide, silicon carbide and boron nitride meet with varying degrees of success; however, none of these materials provided an electrically nonconductive coating. Coatings intended to stick carbon fibers together after a composite burned were sodium silicate, silica gel, ethyl silicate, boric acid and ammonium borate. Of these, only the sodium silicate and silica gel provided any sticking together of fibers. The amount of sticking was insufficient to achieve the desired objectives.

Study of high resistance inorganic coatings on graphite fibers. [for graphite-epoxy composite materials

NASA Technical Reports Server (NTRS)

Galasso, F. S.; Veltri, R. D.; Scola, D. A.

1979-01-01

Coatings made of boron, silicon carbide, silica, and silica-like materials were studied to determine their ability to increase resistance of graphite fibers. The most promising results were attained by chemical vapor depositing silicon carbide on graphite fiber followed by oxidation, and drawing graphite fiber through ethyl silicate followed by appropriate heat treatments. In the silicon carbide coating studies, no degradation of the graphite fibers was observed and resistance values as high as three orders of magnitude higher than that of the uncoated fiber was attained. The strength of a composite fabricated from the coated fiber had a strength which compared favorably with those of composites prepared from uncoated fiber. For the silica-like coated fiber prepared by drawing the graphite fiber through an ethyl silicate solution followed by heating, coated fiber resistances about an order of magnitude greater than that of the uncoated fiber were attained. Composites prepared using these fibers had flexural strengths comparable with those prepared using uncoated fibers, but the shear strengths were lower.

Al-TiC in situ composite coating fabricated by low power pulsed laser cladding on AZ91D magnesium alloy

NASA Astrophysics Data System (ADS)

Yang, Liuqing; Li, Zhiyong; Zhang, Yingqiao; Wei, Shouzheng; Liu, Fuqiang

2018-03-01

Al + (Ti + B4C) composite coating was cladded on AZ91D magnesium alloy by a low power pulsed Nd-YAG laser. The Ti+B4C mixed powder is with the ratio of Ti: B4C = 5:1, which was then mixed with Al powder by weight fraction of 10%, 15% and 20%, respectively. Scanning electron microscopy, energy dispersive spectrometer and X-ray diffraction were used to study the microstructure, chemical composition and phase composition of the coating. Results showed that the coating had satisfied metallurgical bonding with the magnesium substrate. Al3Mg2, Al12Mg17, Al3Ti and TiC were formed by in-situ reaction. The coatings have micro-hardness of 348HV, which is about 5-6 times higher than that of AZ91D. The wear resistance and corrosion resistance of the coatings are enhanced with the addition of the mixed powder.

High gain durable anti-reflective coating

DOEpatents

Maghsoodi, Sina; Brophy, Brenor L.; Colson, Thomas E.; Gonsalves, Peter R.; Abrams, Ze'ev R.

2016-07-26

Disclosed herein are polysilsesquioxane-based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In one embodiment, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, thermal radical initiator, photo radical initiators, crosslinkers, Si--OH condensation catalyst and nano-fillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

Laser cladding of bioactive glass coatings.

PubMed

Comesaña, R; Quintero, F; Lusquiños, F; Pascual, M J; Boutinguiza, M; Durán, A; Pou, J

2010-03-01

Laser cladding by powder injection has been used to produce bioactive glass coatings on titanium alloy (Ti6Al4V) substrates. Bioactive glass compositions alternative to 45S5 Bioglass were demonstrated to exhibit a gradual wetting angle-temperature evolution and therefore a more homogeneous deposition of the coating over the substrate was achieved. Among the different compositions studied, the S520 bioactive glass showed smoother wetting angle-temperature behavior and was successfully used as precursor material to produce bioactive coatings. Coatings processed using a Nd:YAG laser presented calcium silicate crystallization at the surface, with a uniform composition along the coating cross-section, and no significant dilution of the titanium alloy was observed. These coatings maintain similar bioactivity to that of the precursor material as demonstrated by immersion in simulated body fluid. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effects of Interface Modification on Mechanical Behavior of Hi-Nicalon Fiber-Reinforced Celsian Matrix Composites

NASA Technical Reports Server (NTRS)

Bansal, Narottam P.; Eldridge, Jeffrey I.

1997-01-01

Unidirectional celsian matrix composites having approx. 42 volume percent of uncoated or BN/SiC-coated Hi-Nicalon fibers were tested in three-point bend at room temperature. The uncoated fiber-reinforced composites showed catastrophic failure with strength of 210 +/- 35 MPa and a flat fracture surface. In contrast, composites reinforced with BN/SiC-coated fibers exhibited graceful failure with extensive fiber pullout. Values of first matrix cracking stress and strain were 435 +/- 35 MPa and 0.27 +/- 0.01 %, respectively, with ultimate strength as high as 960 MPa. The elastic Young's modulus of the uncoated and BN/SiC-coated fiber-reinforced composites were measured as 184 q 4 GPa and 165 +/- 5 GPa, respectively. Fiber push-through tests and microscopic examination indicated no chemical reaction at the uncoated or coated fiber-matrix interface. The low strength of the uncoated fiber-reinforced composite is probably due to degradation of the fibers from mechanical surface damage during processing. Because both the coated and uncoated fiber reinforced composites exhibited weak interfaces, the beneficial effect of the BN-SiC dual layer is primarily the protection of fibers from mechanical damage during processing.

Investigation into the Coating and Desensitization Effect on HNIW of Paraffin Wax/Stearic Acid Composite System

NASA Astrophysics Data System (ADS)

Wang, Dong-Xu; Chen, Shu-Sen; Jin, Shao-Hua; Shu, Qing-Hai; Jiang, Zhen-Ming; Shang, Feng-Qin; Li, Jin-Xin

2016-01-01

2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW) was bonded by fluorine rubber and then desensitized by paraffin wax (PW), stearic acid (SA), and a PW/SA composite system using an aqueous suspension method. The coating and desensitization effects of the composite systems on HNIW and the influence of the addition of SA on the mechanical properties of the coated HNIW samples were studied. In addition, the PW/SA composite solution was simulated using a molecular dynamics method, and the relationship between the desensitization effect on HNIW and the properties of the composite solution was investigated. The results showed that the PW/SA composite system, of which the desensitization effect on HNIW was between those of the two desensitizers, could effectively coat HNIW and that the composite solution had the most stable and well-distributed state when using benzene as solvent with the mass ratio of PW/SA equal to 7/3 or 3/7, thus resulting in the best desensitization effect on HNIW. Moreover, the addition of stearic acid was successful in enhancing the mechanical properties of the coated HNIW samples.

Magnesium coated phosphate glass fibers for unidirectional reinforcement of polycaprolactone composites.

PubMed

Liu, Xiaoling; Grant, David M; Palmer, Graham; Parsons, Andrew J; Rudd, Chris D; Ahmed, Ifty

2015-10-01

Bioresorbable composites have shown much potential for bone repair applications, as they have the ability to degrade completely over time and their degradation and mechanical properties can be tailored to suit the end application. In this study, phosphate glass fiber (from the system 45% P2 O5-16% CaO-24% MgO-11% Na2 O-4% Fe2 O3 (given in mol%)) were used to reinforce polycaprolactone (PCL) with approximately 20% fiber volume fraction. The glass fiber surfaces were coated with magnesium (Mg) through magnetron sputtering to improve the fiber-matrix interfacial properties. The Mg coating provided a rough fiber surface (roughness (Ra) of about 44nm). Both noncoated and Mg-coated fiber-reinforced composites were assessed. The water uptake and mass loss properties for the composites were assessed in phosphate-buffered saline (PBS) at 37°C for up to 28 days, and ion release profiles were also investigated in both water and PBS media. Inhibition of media influx was observed for the Mg-coated composites. The composite mechanical properties were characterized on the basis of both tensile and flexural tests and their retention in PBS media at 37°C was also investigated. A higher retention of the mechanical properties was observed for the Mg-coated composites over the 28 days degradation period. © 2014 Wiley Periodicals, Inc.

Preparation & characterization of SiO{sub 2} interface layer by dip coating technique on carbon fibre for C{sub f}/SiC composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Kundan, E-mail: kundanemails@gmail.com; Centre for Nanotechnology, Central University of Jharkhand, Ratu-Lohardaga Road, Brambe, Ranchi-835205 INDIA; Jariwala, C., E-mail: chetan@ipr.res.in

Carbon fibres (C{sub f}) are one of the most important reinforced materials for ceramic matrix composites such as C{sub f} - SiC composites and they are generally sought for high temperature applications in as space application, nuclear reactor and automobile industries. But the major problem arise when C{sub f} reinforced composites exposed to high temperature in an oxidizing environment, C{sub f} react with oxygen and burnt away. In present work, we have studied the effect of silica (SiO{sub 2}) coating as a protective coating on C{sub f} for the C{sub f} / SiC composites. The silica solution prepared by themore » sol-gel process and coating on C{sub f} is done by dip coating technique with varying the withdrawing speed i.e. 2, 5, 8 mm/s with fixed dipping cycle (3 Nos.). The uniform silica coating on the C{sub f} is shown by the Scanning Electron Microscope (SEM) analysis. The tensile test shows the increase in tensile strength with respect to increase in withdrawing speed. The isothermal oxidation analysis confirmed enhancement of oxidation resistance of silica coated C{sub f} as compared tothe uncoated C{sub f}.« less

Corrosion resistance and adhesion strength of a spin-assisted layer-by-layer assembled coating on AZ31 magnesium alloy

NASA Astrophysics Data System (ADS)

Zhao, Yan-Bin; Liu, Han-Peng; Li, Chang-Yang; Chen, Yong; Li, Shuo-Qi; Zeng, Rong-Chang; Wang, Zhen-Lin

2018-03-01

A polyvinylpyrrolidone (PVP)/polyacrylic acid (PAA) layer-by-layer (LbL) assembled composite coating with a multilayer structure for the corrosion protection of AZ31 magnesium alloy was prepared by a novel spin-casting method. The microstructure and composition of this coating were investigated by means of SEM, XRD and FT-IR measurements. Moreover, electrochemical, immersion and scratch tests in vitro were performed to measure the corrosion performance and the adhesion strength. These results indicated that the (PVP/PAA)10 composite coating with defect-free, dense and uniform morphologies could be successfully deposited on the surface of magnesium alloy. The coating had excellent corrosion resistance and adhesion strength.

Porous cellulose diacetate-SiO2 composite coating on polyethylene separator for high-performance lithium-ion battery.

PubMed

Chen, Wenju; Shi, Liyi; Wang, Zhuyi; Zhu, Jiefang; Yang, Haijun; Mao, Xufeng; Chi, Mingming; Sun, Lining; Yuan, Shuai

2016-08-20

The developments of high-performance lithium ion battery are eager to the separators with high ionic conductivity and thermal stability. In this work, a new way to adjust the comprehensive properties of inorganic-organic composite separator was investigated. The cellulose diacetate (CDA)-SiO2 composite coating is beneficial for improving the electrolyte wettability and the thermal stability of separators. Interestingly, the pore structure of composite coating can be regulated by the weight ratio of SiO2 precursor tetraethoxysilane (TEOS) in the coating solution. The electronic performance of lithium ion batteries assembled with modified separators are improved compared with the pristine PE separator. When weight ratio of TEOS in the coating solution was 9.4%, the composite separator shows the best comprehensive performance. Compared with the pristine PE separator, its meltdown temperature and the break-elongation at elevated temperature increased. More importantly, the discharge capacity and the capacity retention improved significantly. Copyright © 2016 Elsevier Ltd. All rights reserved.

Parent-child relationship disorders. Part I. Parental overprotection and the development of the Parent Protection Scale.

PubMed

Thomasgard, M; Metz, W P; Edelbrock, C; Shonkoff, J P

1995-08-01

There is a spectrum of parental protective behaviors promoting child safety and security, ranging from neglect to overprotection. This paper describes the development and psychometric properties of a new measure of parental protective behaviors toward children age 2 to 10 years, the Parent Protection Scale (PPS). Items were selected to represent key dimensions of protective behaviors. Factor analyses suggested four subscales: Supervision, Separation Problems, Dependence, and Control. The PPS has acceptable internal consistency, test-retest reliability, and clinical validity. Norms by child age in the form of cutoff points corresponding to +1 SD were determined. Clinical and research uses for the PPS are noted.

Improvement of Interaction in a Composite Structure by Using a Sol-Gel Functional Coating on Carbon Fibers.

PubMed

Szczurek, Anna; Barcikowski, Michał; Leluk, Karol; Babiarczuk, Bartosz; Kaleta, Jerzy; Krzak, Justyna

2017-08-25

The modification of carbon fibers for improving adhesion between fibers and an epoxy resin in composite materials has become the focus of attention. In this work the carbon fiber coating process has been devised in a way preventing the stiffening and clumping of fibers. To improve interactions between coated fibers and a resin in composites, four types of silica coatings with different organic functional groups (3-aminopropyl-coating 1, 3-mercaptopropyl-coating 2, 2-(3,4-epoxycyclohexyl) ethyl-coating 3, methyl-coating 4) were obtained. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to distinguish the changes of a carbon fibers surface after coating deposition. The thickness of the obtained coatings, including the diversity of thickness, was determined by transmission electron microscopy (TEM). The increase in surface free energy (SFE) of modified fibers, including the distinction between the polar and dispersive parts, was examined by wettability measurements using a tensometric test. The developed coating preparation process allowed to cover fibers separately with nanoscale silica layers, which changed their morphology. The introduction of organic functional groups resulted in surface free energy changes, especially an increase in specific polar surface energy components.

Improvement of Interaction in a Composite Structure by Using a Sol-Gel Functional Coating on Carbon Fibers

PubMed Central

Barcikowski, Michał; Leluk, Karol; Babiarczuk, Bartosz; Kaleta, Jerzy

2017-01-01

The modification of carbon fibers for improving adhesion between fibers and an epoxy resin in composite materials has become the focus of attention. In this work the carbon fiber coating process has been devised in a way preventing the stiffening and clumping of fibers. To improve interactions between coated fibers and a resin in composites, four types of silica coatings with different organic functional groups (3-aminopropyl–coating 1, 3-mercaptopropyl–coating 2, 2-(3,4-epoxycyclohexyl) ethyl–coating 3, methyl–coating 4) were obtained. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to distinguish the changes of a carbon fibers surface after coating deposition. The thickness of the obtained coatings, including the diversity of thickness, was determined by transmission electron microscopy (TEM). The increase in surface free energy (SFE) of modified fibers, including the distinction between the polar and dispersive parts, was examined by wettability measurements using a tensometric test. The developed coating preparation process allowed to cover fibers separately with nanoscale silica layers, which changed their morphology. The introduction of organic functional groups resulted in surface free energy changes, especially an increase in specific polar surface energy components. PMID:28841187

Infrared spectroscopy, nano-mechanical properties, and scratch resistance of esthetic orthodontic coated archwires.

PubMed

da Silva, Dayanne Lopes; Santos, Emanuel; Camargo, Sérgio de Souza; Ruellas, Antônio Carlos de Oliveira

2015-09-01

To evaluate the material composition, mechanical properties (hardness and elastic modulus), and scratch resistance of the coating of four commercialized esthetic orthodontic archwires. The coating composition of esthetic archwires was assessed by Fourier-transform infrared spectroscopy (FTIR). Coating hardness and elastic modulus were analyzed with instrumented nano-indentation tests. Scratch resistance of coatings was evaluated by scratch test. Coating micromorphologic characteristics after scratch tests were observed in a scanning electron microscope. Statistical differences were investigated using analysis of variance and Tukey post hoc test. The FTIR results indicate that all analyzed coatings were markedly characterized by the benzene peak at about 1500 cm(-1). The coating hardness and elastic modulus average values ranged from 0.17 to 0.23 GPa and from 5.0 to 7.6 GPa, respectively. Scratch test showed a high coating elasticity after load removal with elastic recoveries >60%, but different failure features could be observed along the scratches. The coatings of esthetic archwires evaluated are probably a composite of polyester and polytetrafluoroethylene. Delamination, crack propagation, and debris generation could be observed along the coating scratches and could influence its durability in the oral environment.

Antimicrobial polycaprolactone/polyethylene glycol embedded lysozyme coatings of Ti implants for osteoblast functional properties in tissue engineering

NASA Astrophysics Data System (ADS)

Visan, A.; Cristescu, R.; Stefan, N.; Miroiu, M.; Nita, C.; Socol, M.; Florica, C.; Rasoga, O.; Zgura, I.; Sima, L. E.; Chiritoiu, M.; Chifiriuc, M. C.; Holban, A. M.; Mihailescu, I. N.; Socol, G.

2017-09-01

In this study, coatings based on lysozyme embedded into a matrix of polyethylene glycol (PEG) and polycaprolactone (PCL) were fabricated by two different methods (Matrix Assisted Pulsed Laser Evaporation - MAPLE and Dip Coating) for obtaining antimicrobial coatings envisaged for long term medical applications. Coatings with different PEG:PCL compositions (3:1; 1:1; 1:3) were synthesized in order to evaluate the antimicrobial activity of lysozyme embedded into the polymeric matrix. The main surface features, such as roughness and wettability, with impact on the microbial adhesion as well as on the eukaryote cell function were measured. The obtained composite coatings exhibited a significant antibacterial activity against Escherichia coli, Bacillus subtilis, Enterococcus faecalis and Staphylococcus aureus strains. As well, specific blended coatings showed appropriate viability, good spreading and normal cell morphology of SaOs2 human osteoblasts and mesenchymal stem cells (MSCs). These investigations highlight the suitability of biodegradable composites as implant coatings for decreasing the risk of bacterial contamination associated with prosthetic procedures.

Synthesis and characterization of in situ TiC-TiB2 composite coatings by reactive plasma spraying on a magnesium alloy

NASA Astrophysics Data System (ADS)

Zou, Binglin; Tao, Shunyan; Huang, Wenzhi; Khan, Zuhair S.; Fan, Xizhi; Gu, Lijian; Wang, Ying; Xu, Jiaying; Cai, Xiaolong; Ma, Hongmei; Cao, Xueqiang

2013-01-01

TiC-TiB2 composite coatings were successfully synthesized using the technique of reactive plasma spraying (RPS) on a magnesium alloy. Phase composition, microstructure and wear resistance of the coatings were characterized by using X-ray diffraction, scanning electron microscopy and pin-on-disk wear test, respectively. The results showed that the resultant product in the RPS coatings was composed of TiC and TiB2. Depending on the ignition of self-propagating high-temperature synthesis reaction in the agglomerate particles, the RPS coatings displayed porous and dense microstructures. The porosity of the RPS coatings, to some extent, decreased when the feed powders were plasma sprayed with Ni powders. The RPS coatings provided good wear resistance for the substrate under various loads. For high loads (e.g., ≥15 N), the wear resistance could be significantly improved by the proper addition of Ni into the RPS coatings.

Electrophoretic co-deposition of PEEK-hydroxyapatite composite coatings for biomedical applications.

PubMed

Baştan, Fatih E; Atiq Ur Rehman, Muhammad; Avcu, Yasemin Yıldıran; Avcu, Egemen; Üstel, Fatih; Boccaccini, Aldo R

2018-05-03

This study focuses on the optimization of electrophoretic deposition (EPD) and suspension parameters for producing PEEK-hydroxyapatite (HA) coatings with feasible microstructure, adhesion strength, and in-vitro bioactivity. Nanostructured hydroxyapatite (HA) micro-granules were incorporated with PEEK to form PEEK-hydroxyapatite composite coatings via EPD. After EPD, a heat-treatment at 375 °C was applied for densification of the coatings and for enhancing the adhesion between the coatings and the substrates. It was found that both adhesion strength and in-vitro bioactivity of the coatings were dependent on the PEEK and HA relative contents. Thus, increasing the amount of HA improved the bioactivity while decreased the adhesion strength of the coatings. Apatite-like layer formation was observed on coatings with high HA content after incubation for three days in simulated body fluid (SBF). Finally, a deposition mechanism was proposed for the EPD of the PEEK-hydroxyapatite composite system. Copyright © 2018 Elsevier B.V. All rights reserved.

Controlled-release fertilizer composition substantially coated with an impermeable layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ankeny, Mark

2016-03-29

A controlled-release fertilizer composition is provided that is substantially coated with an impermeable layer. The fertilizer composition may further include one or more hollow sections to allow for root penetration and efficient delivery of nutrients.

Interpenetrating phase ceramic/polymer composite coatings: Fabrication and characterization

NASA Astrophysics Data System (ADS)

Craig, Bradley Dene

The goals of this thesis research were to fabricate interpenetrating phase composite (IPC) ceramic/polymer coatings and to investigate the effect of the interconnected microstructure on the physical and wear properties of the coatings. IPC coatings with an interpenetrating phase microstructure were successfully fabricated by first forming a porous ceramic with an interconnected microstructure using a chemical bonding route (mainly reacting alpha-alumina (0.3 mum) with orthophosphoric acid to form a phosphate bond). Porosity within these ceramic coatings was easily controlled between 20 and 50 vol. % by phosphoric acid addition, and was measured by a new porosity measurement technique (thermogravimetric volatilization of liquids, or TVL) which was developed. The resulting ceramic preforms were infiltrated with a UV and thermally curable cycloaliphatic epoxide resin and cured. This fabrication route resulted in composite coatings with thicknesses ranging from ˜1mum to 100 mum with complete filling of open pore space. The physical properties of the composite coatings, including microhardness, flexural modulus and wear resistance, were evaluated as a function of processing variables, including orthophosphoric acid content and ceramic phase firing temperature, which affected the microstructure and interparticulate bonding between particles in the coatings. For example, microhardness increased from ˜30 on the Vicker's scale to well over 200 as interparticulate bonding was increased in the ceramic phase. Additionally, Taber wear resistance in the best TPC coatings was found to approach that of fully-densified alumina under certain conditions. Several factors were found to influence the wear mechanism in the IPC coating materials. Forming strong connections between ceramic particles led to up to an order of magnitude increase in the wear resistance. Additionally, coating microhardness and ceramic/polymer interfacial strength were studied and found to be important in determining the wear mechanism and wear resistance of IPC composite coatings. A qualitative theory for wear mechanisms in these coatings was developed. Finally, a series of transparent coatings were developed via a similar processing route, using smaller (˜90 nm) boehmite particles instead of 0.3 mum alpha-alumina. Physical property control was found to mimic that found in opaque coatings, and showed increasing surface adsorption characteristics with increasing phosphoric acid content.

Erosion Coatings Developed to Increase the Life and Durability of Composites

NASA Technical Reports Server (NTRS)

Sutter, James K.; Naik, Subhash K.; Bowman, Cheryl L.; Siefker, Robert; Miyoshi, Kazuhisa; Perusek, Gail P.

2004-01-01

Both the NASA Glenn Research Center and the Allison Advanced Development Company (AADC) have worked to develop and demonstrate erosion-resistant coatings that would increase the life and durability of composite materials used in commercial aircraft engines. These composite materials reduce component weight by 20 to 30 percent and result in less fuel burn and emissions and more fuel savings. Previously, however, their use was limited because of poor erosion resistance, which causes concerns about safety and leads to high maintenance costs. The coatings were tested by the University of Cincinnati, and the composites were manufactured by Texas Composites and coated by Engelhard and NASA Glenn. Rolls-Royce Corporation uses composite materials, which are stronger and less dense than steel or titanium, to make bypass vanes for their AE3007 engines. These engines are widely used in regional jet aircraft (Embraer) and unmanned air vehicles such as the Northrop Grumman Global Hawk. Coatings developed by NASA/Rolls-Royce can reduce erosion from abrasive materials and from impurities in the air that pass over these vanes, allowing Rolls-Royce to take advantage of the benefits of composite materials over titanium without the added costs of increased maintenance and/or engine failure. The Higher Operating Temperature Propulsion Components (HOTPC) Project developed cost-effective, durable coatings as part of NASA's goal to increase aviation system capacity growth. These erosion coatings will reduce the number of special inspections or instances of discontinued service due to erosion, allowing aircraft capacity to be maintained without inconveniencing the traveling public. A specific example of extending component life showed that these coatings increased the life of graphite fiber and polymer composite bypass vanes up to 8 times over that of the uncoated vanes. This increased durability allows components to operate to full design life without the fear of wear or failure. Recently, Rolls-Royce completed over 2000 hr of engine testing with the coated fan exit bypass vanes. There was no loss of coating after nearly 5000 typical engine cycles. Midway through the engine tests, the coated vanes were removed from the engine during a scheduled maintenance and inspection period. The vanes were shipped back to Glenn, where they underwent further stress testing in the Structural Dynamics Lab, mimicking more extreme conditions than those typical of the AE3007 engine cycle. These vanes were then replaced in the AE3007 and subjected to another 1000 hr of engine tests. Once again, there was no loss of coating and only a minimal appearance of cracking.

Effect of Copper Coated SiC Reinforcements on Microstructure, Mechanical Properties and Wear of Aluminium Composites

NASA Astrophysics Data System (ADS)

Kori, P. S.; Vanarotti, Mohan; Angadi, B. M.; Nagathan, V. V.; Auradi, V.; Sakri, M. I.

2017-08-01

Experimental investigations are carried out to study the influence of copper coated Silicon carbide (SiC) reinforcements in Aluminum (Al) based Al-SiC composites. Wear behavior and mechanical Properties like, ultimate tensile strength (UTS) and hardness are studied in the present work. Experimental results clearly revealed that, an addition of SiC particles (5, 10 and 15 Wt %) has lead in the improvement of hardness and ultimate tensile strength. Al-SiC composites containing the Copper coated SiC reinforcements showed better improvement in mechanical properties compared to uncoated ones. Characterization of Al-SiC composites are carried out using optical photomicrography and SEM analysis. Wear tests are carried out to study the effects of composition and normal pressure using Pin-On Disc wear testing machine. Results suggested that, wear rate decreases with increasing SiC composition, further an improvement in wear resistance is observed with copper coated SiC reinforcements in the Al-SiC metal matrix composites (MMC’s).

The effect of graphene oxide on surface features, biological performance and bio-stability of calcium phosphate coating applied by pulse electrochemical deposition

NASA Astrophysics Data System (ADS)

Fathyunes, Leila; Khalil-Allafi, Jafar

2018-04-01

In the current study, the effect of second phase of graphene oxide (GO) on the surface features and biological behavior of calcium phosphate (CaP) coating was evaluated. To do so, the GO-CaP composite coating was applied on TiO2 nanotubular arrays using pulse electrochemical deposition. The SEM and AFM images showed that, the CaP-based coating with uniform and refined microstructure could be formed through its compositing with GO sheets. The biological assessment of the coatings was also conducted by cell culture test and MTT assay. Based on findings, the GO-CaP coating showed the better biocompatibility compared to the CaP coating. This could be owing to the fact that the composite coating provided the lower roughness, moderately wettable surface with a contact angle of 23.5° ± 2.6° and the higher stability in the biological environments because of being involved with only the stable phase of CHA. However, in the CaP coating, spreading of cells could be limited by the plate-like crystals with larger size. The higher solubility of the CaP coating in the cell culture medium possibly owing to the existence of some metastable CaP phases like OCP in addition to the dominant phase of CHA in this coating could be another reason for its less biocompatibility. At last, the CaP coating showed the higher apatite-forming ability in SBF solution after its compositing with GO.

Thin coatings for protecting titanium aluminides in high-temperature oxidizing environments

NASA Technical Reports Server (NTRS)

Wiedemann, K. E.; Taylor, P. J.; Clark, R. K.; Wallace, T. A.

1991-01-01

Titanium aluminides have high specific strengths at high temperatures but are susceptible to environmental attack. Their use in many aerospace applications would require that they be protected with coatings that, for structural efficiency, must be thin. It is conceivable that acceptable coatings might be found in several oxide systems, and consequently, oxide coatings of many compositions were prepared from sol-gels for study. Response-surface methodology was used to refine coating compositions and factorial experiments were used to develop coating strategies. Oxygen permeability diagrams of two-layer coatings for several oxide systems, an analysis of multiple-layer coatings on rough and polished surfaces, and modeling of the oxidation weight gain are presented.

Sol-gel derived C-SiC composites and protective coatings for sustained durability in the space environment

NASA Astrophysics Data System (ADS)

Haruvy, Yair; Liedtke, Volker

2003-09-01

Composites and coatings were produced via the fast sol-gel process of a mixture of alkoxysilane precursors. The composites were comprised of carbon fibers, fabrics, or their precursors as reinforcement, and sol-gel-derived silicon carbide as matrix, aiming at high-temperature stable ceramics that can be utilized for re-entry structures. The protective coatings were comprised of fluorine-rich sol-gel derived resins, which exhibit high flexibility and coherence to provide sustained ATOX protection necessary for LEO space-exposed elements. For producing the composites, the sol-gel-derived resin is cast onto the reinforcement fibers/fabrics mat (carbon or its precursors) to produce a 'green' composite that is being cured. The 'green' composite is converted into a C-SiC composite via a gradual heat-pressure process under inert atmosphere, during which the organic substituents on the silicon atoms undergo internal oxidative pyrolysis via the schematic reaction: (SiRO3/2)n -> SiC + CO2 + H2O. The composition of the resultant silicon-oxi-carbide is tailorable via modifying the composition of the sol-gel reactants. The reinforcement, when made of carbon precursors, is converted into carbon during the heat-and-pressure processing as well. The C-SiC composites thus derived exhibit superior thermal stability and comparable thermal conductivity, combined with good mechanical strength features and failure resistance, which render them greatly applicable for re-entry shielding, heat-exchange pipes, and the like. Fluorine rich sol-gel derived coatings were developed as well, via the use of HF rich sol-gel process. These coatings provide oxidation-protection via the silica formation process, together with flexibility that allows 18,000 repetitive folding of the coating without cracking.

Development and Initial Validation of the Performance Perfectionism Scale for Sport (PPS-S)

ERIC Educational Resources Information Center

Hill, Andrew P.; Appleton, Paul R.; Mallinson, Sarah H.

2016-01-01

Valid and reliable instruments are required to appropriately study perfectionism. With this in mind, three studies are presented that describe the development and initial validation of a new instrument designed to measure multidimensional performance perfectionism for use in sport (Performance Perfectionism Scale--Sport [PPS-S]). The instrument is…

42 CFR 1001.1401 - Violations of PPS corrective action.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 5 2010-10-01 2010-10-01 false Violations of PPS corrective action. 1001.1401 Section 1001.1401 Public Health OFFICE OF INSPECTOR GENERAL-HEALTH CARE, DEPARTMENT OF HEALTH AND HUMAN... documented history of criminal, civil or administrative wrongdoing (The lack of any prior record is to be...

Assessing Object-to-Picture and Picture-to-Object Matching as Prerequisite Skills for Pictorial Preference Assessments

ERIC Educational Resources Information Center

Clevenger, Theresa M.; Graff, Richard B.

2005-01-01

Tangible and pictorial paired-stimulus (PPS) preference assessments were compared for 6 individuals with developmental disabilities. During tangible and PPS assessments, two edible items or photographs were presented on each trial, respectively, and approach responses were recorded. Both assessments yielded similar preference hierarchies for 3…

Evaluation of metallized paint coatings for composite spacecraft structures

NASA Technical Reports Server (NTRS)

Brzuskiewicz, John E.

1990-01-01

The extreme temperature excursions of composite spacecraft structures in LEO must be minimized through the use of thermal-control coatings. Attention is presently given to tests of silicone resin coatings which were pigmented with either leafing aluminum or combinations of leafing aluminum with silicate-treated zinc oxide pigment. Atomic oxygen, UV/vacuum, and outgassing screening tests were conducted on several such coating formulations in order to characterize the performance characteristics of this coating concept. Performance was found to depend on pigment volume concentration.

Formation of protective composite coatings with the use of SPTFE suspensions

NASA Astrophysics Data System (ADS)

Nadaraia, K. V.; Mashtalyar, D. V.; Sinebryukhov, S. L.; Gnedenkov, S. V.

2017-09-01

The method of protective composite coatings formation with the use of the plasma electrolytic oxidation (PEO) and subsequent treatment in isopropanol or aqueous suspension of the superdispersed polytetrafluoroethylene (SPTFE) have been developed. Morphological, electrochemical and tribological studies, as well as wetting ability of the protective coatings have been carried out. The obtained results corroborated the increase of the corrosion and wear resistance parameters for the polymer-containing coating in comparison with the base PEO-coating and uncoated material.

Comparison of gene expression levels of appA, ppsR, and EL368 in Erythrobacter litoralis spheroplasts under aerobic and anaerobic conditions, and under blue light, red light, and dark conditions.

PubMed

Nishino, Koki; Takahashi, Sawako; Nishida, Hiromi

2018-03-31

We compared the gene expression levels of the blue-light-responsive genes, appA (encoding photosynthesis promoting protein AppA), ppsR (encoding photosynthesis suppressing protein PpsR), and EL368 (encoding a blue-light-activated histidine kinase with a light, oxygen, or voltage domain) between aerobic and anaerobic conditions in spheroplasts of the aerobic photosynthetic bacterium Erythrobacter litoralis. The spheroplasts conducted photosynthesis under red light but not under blue light. All three blue-light-responsive genes showed higher expression under aerobic conditions than under anaerobic conditions under blue light. In contrast, under red light, although the expression level of appA was higher in the presence of oxygen than in the absence of oxygen, the expression levels of ppsR and EL368 were similar in the presence and absence of oxygen. Our findings demonstrate that the expression of blue-light-responsive genes is strongly affected by oxygen in E. litoralis spheroplasts.

76 FR 68525 - Medicare Program; Home Health Prospective Payment System Rate Update for Calendar Year 2012

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-04

...This final rule sets forth updates to the home health prospective payment system (HH PPS) rates, including: the national standardized 60-day episode rates; the national per-visit rates; and the low utilization payment amount (LUPA) under the Medicare PPS for home health agencies effective January 1, 2012. This rule applies a 1.4 percent update factor to the episode rates, which reflects a 1 percent reduction applied to the 2.4 percent market basket update factor, as mandated by the Affordable Care Act. This rule also updates the wage index used under the HH PPS, and further reduces home health payments to account for continued nominal growth in case-mix which is unrelated to changes in patient health status. This rule removes two hypertension codes from the HH PPS case-mix system, thereby requiring recalibration of the case-mix weights. In addition, the rule implements two structural changes designed to decrease incentives to upcode and provide unneeded therapy services. Finally, this rule incorporates additional flexibility regarding face-to-face encounters with providers related to home health care.

Early performance of the 12-GHz, 200-watt transmitter experiment package in the communications technology satellite

NASA Technical Reports Server (NTRS)

1977-01-01

Measured performance characteristics of the transmitter experiment package (TEP) aboard the Communications Technology Satellite for the first 90 operating days in orbit are presented. The TEP consists of a nominal 200-watt output stage tube (OST), a supporting power processing system (PPS), and a variable-conductance heat pipe system (VCHPS). The OST, a traveling-wave tube augmented with a 10-stage depressed collector, has an overall saturated average efficiency of 51.5 percent and an average saturated radiofrequency (RF) output power at center-band frequency of 240 watts. The PPS operated with a measured efficiency of 86.5 percent to 88.5 percent. The VCHPS, using three pipes to conduct heat from the PPS and the body of the OST to a 52-centimeter by 124-centimeter (20.5-in. by 48.75-in.) radiator fin, maintained by the PPS baseplate temperature below 50 C for all operating conditions. The TEP performance characteristics presented include frequency response, RF output power, efficiency, and distortions. Communications characteristics were evaluated by using both video and audio modulated signals.

Simultaneous 10 Gbps data and polarization-based pulse-per-second clock transmission using a single VCSEL for high-speed optical fibre access networks

NASA Astrophysics Data System (ADS)

Isoe, G. M.; Wassin, S.; Gamatham, R. R. G.; Leitch, A. W. R.; Gibbon, T. B.

2017-01-01

Access networks based on vertical cavity surface emitting laser (VCSEL) transmitters offer alternative solution in delivering different high bandwidth, cost effective services to the customer premises. Clock and reference frequency distribution is critical for applications such as Coordinated Universal Time (UTC), GPS, banking and big data science projects. Simultaneous distribution of both data and timing signals over shared infrastructure is thus desirable. In this paper, we propose and experimentally demonstrate a novel, cost-effective technique for multi-signal modulation on a single VCSEL transmitter. Two signal types, an intensity modulated 10 Gbps data signal and a polarization-based pulse per second (PPS) clock signal are directly modulated onto a single VCSEL carrier at 1310 nm. Spectral efficiency is maximized by exploiting inherent orthogonal polarization switching of the VCSEL with changing bias in transmission of the PPS signal. A 10 Gbps VCSEL transmission with PPS over 11 km of G.652 fibre introduced a transmission penalty of 0.52 dB. The contribution of PPS to this penalty was found to be 0.08 dB.

Concomitant CNS pathology in a patient with amyotropic lateral sclerosis following poliomyelitis in childhood.

PubMed

Casula, M; Steentjes, K; Aronica, E; van Geel, B M; Troost, D

2011-01-01

Post-polio syndrome (PPS) develops in approximately 30% of polio survivors several decades after the acute attack of paralytic poliomyelitis. Some of these patients develop post-poliomyelitis muscular atrophy (PPMA) which is characterized by a slowly progressive muscle weakness. Due to its clinicopathological features, investigators have often studied PPS and PPMA in association with amyotrophic lateral sclerosis (ALS), the underlying hypothesis being an increased risk of developing ALS from a prior acute paralytic poliomyelitis. Various studies, however, have indicated that de novo ALS cases in patients with prior acute paralytic poliomyelitis are rare. Herein, we describe a rare case of a 75-year-old woman who at post-mortem examination presented a combination of a PPS with proven histopathological sporadic ALS features. Furthermore, neuropathology of this case also revealed several other histopathological findings reminiscent of a tauopathy, synucleinopathy and amyloid angiopathy and a large pituitary cyst. To our knowledge, this is the first reported case of PPS with clear pathological hallmarks of sporadic ALS, including ubiquitin-, TDP-43, phosphorylated TDP-43- and p62-positive inclusions, with accompanying features compatible with Alzheimer's and Parkinson's disease.

Medicare program; home health prospective payment system rate update for calendar year 2012. Final rule.

PubMed

2011-11-04

This final rule sets forth updates to the home health prospective payment system (HH PPS) rates, including: the national standardized 60-day episode rates; the national per-visit rates; and the low utilization payment amount (LUPA) under the Medicare PPS for home health agencies effective January 1, 2012. This rule applies a 1.4 percent update factor to the episode rates, which reflects a 1 percent reduction applied to the 2.4 percent market basket update factor, as mandated by the Affordable Care Act. This rule also updates the wage index used under the HH PPS, and further reduces home health payments to account for continued nominal growth in case-mix which is unrelated to changes in patient health status. This rule removes two hypertension codes from the HH PPS case-mix system, thereby requiring recalibration of the case-mix weights. In addition, the rule implements two structural changes designed to decrease incentives to upcode and provide unneeded therapy services. Finally, this rule incorporates additional flexibility regarding face-to-face encounters with providers related to home health care.

Effect of Powder-Feeding Modes During Plasma Spray on the Properties of Tungsten Carbide Composite Coatings

NASA Astrophysics Data System (ADS)

Zhong, Yi-ming; Du, Xiao-dong; Wu, Gang

2017-05-01

A WC-reinforced composite coating was fabricated on the surface of 45 steel samples by plasma, cladding process with WC powder added to the molten pool synchronously or in the tail of the molten pool. The microstructure, phase composition, and element distribution in the coating were analyzed. The results show that the undissolved WC particles and crystallized carbide (WC, W2C) were distributed uniformly in the sub-eutectic matrix in both cases. Fewer of the WC particles are dissolved in the matrix when they are injected into the tail of the molten pool. There are fewer needle-like tungsten carbide formations seen in the composite coating fabricated by back-feeding process than in that formed by synchronous feeding. The former results in a finer microstructure and a higher concentration gradient of elements near the interface between the WC particles and the coating matrix.

Effects of oleic acid surface coating on the properties of nickel ferrite nanoparticles/PLA composites.

PubMed

Yin, Hong; Chow, Gan-Moog

2009-11-01

Nickel ferrite nanoparticles with or without oleic acid surface coating were mixed with poly(D,L-lactide) (PLA) by double emulsion method. If the nanoparticles were prepared without oleic acid coating, they adsorbed on the PLA surface. If the nanoparticles were coated with oleic acid, they could be readily encapsulated within the PLA microspheres. A slight depression in glass transition temperature was found in all composites and it could be related to the interfacial energies between nanoparticles and PLA. Optimum mixed composite was achieved by reducing interfacial energy. However, loading capacity was limited in this composite. Increasing the amount of nickel ferrite nanoparticles was not useful to increase loading capacity. Cytotoxicity of the composite decreased significantly when nickel ferrite nanoparticles were effectively encapsulated in PLA microspheres. (c) 2008 Wiley Periodicals, Inc.

Fluorine-containing composition for forming anti-reflection film on resist surface and pattern formation method

DOEpatents

Nishi, Mineo; Makishima, Hideo

1996-01-01

A composition for forming anti-reflection film on resist surface which comprises an aqueous solution of a water soluble fluorine compound, and a pattern formation method which comprises the steps of coating a photoresist composition on a substrate; coating the above-mentioned composition for forming anti-reflection film; exposing the coated film to form a specific pattern; and developing the photoresist, are provided. Since the composition for forming anti-reflection film can be coated on the photoresist in the form of an aqueous solution, not only the anti-reflection film can be formed easily, but also, the film can be removed easily by rinsing with water or alkali development. Therefore, by the pattern formation method according to the present invention, it is possible to form a pattern easily with a high dimensional accuracy.

Micro-oxidation treatment to improve bonding strength of Sr and Na co-substituted hydroxyapatite coatings for carbon/carbon composites

NASA Astrophysics Data System (ADS)

Zhang, Leilei; Li, Hejun; Li, Kezhi; Zhang, Yulei; Liu, Shoujie; Guo, Qian; Li, Shaoxian

2016-08-01

To improve the bonding strength of Sr and Na co-substituted hydroxyapatite (SNH) coatings for carbon/carbon composites, carbon/carbon composites are surface modified by micro-oxidation treatment. The micro-oxidation treatment could generate large number of pores containing oxygenic functional groups on the surface of carbon/carbon composites. SNH is nucleated on the inwall of the pores and form a flaky shape coating with 10-50 nm in thickness and 200-900 nm in width. The bonding strength between SNH coating and carbon/carbon composites increases from 4.27 ± 0.26 MPa to 10.57 ± 0.38 MPa after the micro-oxidation treatment. The promotion of bonding strength is mainly attributed to the pinning effect caused by the pores and chemical bonding generated by the oxygenic functional groups.

CVD Fiber Coatings for Al2O3/NiAl Composites

NASA Technical Reports Server (NTRS)

Boss, Daniel E.

1995-01-01

While sapphire-fiber-reinforced nickel aluminide (Al2O3/NiAl) composites are an attractive candidate for high-temperature structures, the significant difference in the coefficient of thermal expansion between the NiAl matrix and the sapphire fiber creates substantial residual stresses in the composite. This study seeks to produce two fiber-coating systems with the potential to reduce the residual stresses in the sapphire/NiAl composite system. Chemical vapor deposition (CVD) was used to produce both the compensating and compliant-fiber coatings for use in sapphire/NiAl composites. A special reactor was designed and built to produce the FGM and to handle the toxic nickel precursors. This process was successfully used to produce 500-foot lengths of fiber with coating thicknesses of approximately 3 microns, 5 microns, and 10 microns.

Raman Study of Uncoated and p-BN/SiC-Coated Hi-Nicalon Fiber-Reinforced Celsian Matrix Composites. Part 1; Distribution and Nanostructure of Different Phases

NASA Technical Reports Server (NTRS)

Gouadec, Gwenael; Colomban, Philippe; Bansal, Narottam P.

2000-01-01

Hi-Nicalon fiber reinforced celsian matrix composites were characterized by Raman spectroscopy and imaging, using several laser wavelengths. Composite #1 is reinforced by as-received fibers while coatings of p-BN and SiC protect the fibers in composite #2. The matrix contains traces of the hexagonal phase of celsian, which is concentrated in the neighborhood of fibers in composite #1. Some free silicon was evident in the coating of composite #2 which might involve a {BN + SiC yields BNC + Si} "reaction" at the p-BN/SiC interface. Careful analysis of C-C peaks revealed no abnormal degradation of the fiber core in the composites.

Polymer infiltration studies

NASA Technical Reports Server (NTRS)

Marchello, Joseph M.

1994-01-01

During the past three months, significant progress has been made on the preparation of carbon fiber composites using advanced polymer resins. The results are set forth in recent reports and publications, and will be presented at forthcoming national and international meetings. Current and ongoing research activities reported herein include: textile composites from powder-coated towpreg - role of surface coating in braiding; prepregger hot sled operation in making tape from powder coated tow; ribbonizing powder-impregnated towpreg; textile composites from powder-coated towpreg - role of bulk factor in consolidation; powder curtain prepreg process improvements in doctoring of powder; and hot/cold shoe for ATP open-section part warpage control.

TiC-Fe-Based Composite Coating Prepared by Self-Propagating High-Temperature Synthesis

NASA Astrophysics Data System (ADS)

He, Shen; Fan, Xi'an; Chang, Qingming; Xiao, Lixiang

2017-06-01

TiC-Fe-based composite coatings were prepared in situ by self-propagating high-temperature synthesis combined with vacuum expendable pattern casting process. The band-like TiC phase embedded in a continuous Fe binder. There were no obvious defects and impurities at the interface between coatings and matrices. Fe presented consecutively in the coating zones and substrate zones without interruption and the microhardness in the cross-sectional area of the coating-matrix reduces continuously from the coating to the matrix area, indicating a good metallurgical bonding between the coatings and matrices. The effect of casting temperature on the microstructure and hardness of TiC-Fe-based composite coating was investigated in detail. The TiC particles formed at low casting temperature were nearly spherical in shape, and the size of TiC particles increased with increasing casting temperature due to more agglomeration. The hardness of the coatings increased first and then decreased with increasing casting temperature, and reached the highest value of 68 HRC when the casting temperature was 1773 K (1500 °C), which was twice more than that of the matrix.

Microstructures and Properties of Laser Cladding Al-TiC-CeO2 Composite Coatings

PubMed Central

Kong, Dejun; Song, Renguo

2018-01-01

Al-TiC-CeO2 composite coatings have been prepared by using a laser cladding technique, and the microstructure and properties of the resulting composite coatings have been investigated using scanning electron microscopy (SEM), a 3D microscope system, X-ray diffraction (XRD), micro-hardness testing, X-ray stress measurements, friction and wear testing, and an electrochemical workstation. The results showed that an Al-Fe phase appears in the coatings under different applied laser powers and shows good metallurgical bonding with the matrix. The dilution rate of the coating first decreases and then increases with increasing laser power. The coating was transformed from massive and short rod-like structures into a fine granular structure, and the effect of fine grain strengthening is significant. The microhardness of the coatings first decreases and then increases with increasing laser power, and the maximum microhardness can reach 964.3 HV0.2. In addition, the residual stress of the coating surface was tensile stress, and crack size increases with increasing stress. When the laser power was 1.6 kW, the coating showed high corrosion resistance. PMID:29373555

Microstructures and Properties of Laser Cladding Al-TiC-CeO₂ Composite Coatings.

PubMed

He, Xing; Kong, Dejun; Song, Renguo

2018-01-26

Al-TiC-CeO₂ composite coatings have been prepared by using a laser cladding technique, and the microstructure and properties of the resulting composite coatings have been investigated using scanning electron microscopy (SEM), a 3D microscope system, X-ray diffraction (XRD), micro-hardness testing, X-ray stress measurements, friction and wear testing, and an electrochemical workstation. The results showed that an Al-Fe phase appears in the coatings under different applied laser powers and shows good metallurgical bonding with the matrix. The dilution rate of the coating first decreases and then increases with increasing laser power. The coating was transformed from massive and short rod-like structures into a fine granular structure, and the effect of fine grain strengthening is significant. The microhardness of the coatings first decreases and then increases with increasing laser power, and the maximum microhardness can reach 964.3 HV 0.2 . In addition, the residual stress of the coating surface was tensile stress, and crack size increases with increasing stress. When the laser power was 1.6 kW, the coating showed high corrosion resistance.

Advanced membrane electrode assemblies for fuel cells

DOEpatents

Kim, Yu Seung; Pivovar, Bryan S.

2012-07-24

A method of preparing advanced membrane electrode assemblies (MEA) for use in fuel cells. A base polymer is selected for a base membrane. An electrode composition is selected to optimize properties exhibited by the membrane electrode assembly based on the selection of the base polymer. A property-tuning coating layer composition is selected based on compatibility with the base polymer and the electrode composition. A solvent is selected based on the interaction of the solvent with the base polymer and the property-tuning coating layer composition. The MEA is assembled by preparing the base membrane and then applying the property-tuning coating layer to form a composite membrane. Finally, a catalyst is applied to the composite membrane.

Advanced membrane electrode assemblies for fuel cells

DOEpatents

Kim, Yu Seung; Pivovar, Bryan S

2014-02-25

A method of preparing advanced membrane electrode assemblies (MEA) for use in fuel cells. A base polymer is selected for a base membrane. An electrode composition is selected to optimize properties exhibited by the membrane electrode assembly based on the selection of the base polymer. A property-tuning coating layer composition is selected based on compatibility with the base polymer and the electrode composition. A solvent is selected based on the interaction of the solvent with the base polymer and the property-tuning coating layer composition. The MEA is assembled by preparing the base membrane and then applying the property-tuning coating layer to form a composite membrane. Finally, a catalyst is applied to the composite membrane.

Understanding the Role of Temperature and Cathode Composition on Interface and Bulk: Optimizing Aluminum Oxide Coatings for Li-Ion Cathodes.

PubMed

Han, Binghong; Paulauskas, Tadas; Key, Baris; Peebles, Cameron; Park, Joong Sun; Klie, Robert F; Vaughey, John T; Dogan, Fulya

2017-05-03

Surface coating of cathode materials with Al 2 O 3 has been shown to be a promising method for cathode stabilization and improved cycling performance at high operating voltages. However, a detailed understanding on how coating process and cathode composition change the chemical composition, morphology, and distribution of coating within the cathode interface and bulk lattice is still missing. In this study, we use a wet-chemical method to synthesize a series of Al 2 O 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 and LiCoO 2 cathodes treated under various annealing temperatures and a combination of structural characterization techniques to understand the composition, homogeneity, and morphology of the coating layer and the bulk cathode. Nuclear magnetic resonance and electron microscopy results reveal that the nature of the interface is highly dependent on the annealing temperature and cathode composition. For Al 2 O 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 , higher annealing temperature leads to more homogeneous and more closely attached coating on cathode materials, corresponding to better electrochemical performance. Lower Al 2 O 3 coating content is found to be helpful to further improve the initial capacity and cyclability, which can greatly outperform the pristine cathode material. For Al 2 O 3 -coated LiCoO 2 , the incorporation of Al into the cathode lattice is observed after annealing at high temperatures, implying the transformation from "surface coatings" to "dopants", which is not observed for LiNi 0.5 Co 0.2 Mn 0.3 O 2 . As a result, Al 2 O 3 -coated LiCoO 2 annealed at higher temperature shows similar initial capacity but lower retention compared to that annealed at a lower temperature, due to the intercalation of surface alumina into the bulk layered structure forming a solid solution.

Environmental colonization and onward clonal transmission of carbapenem-resistant Acinetobacter baumannii (CRAB) in a medical intensive care unit: the case for environmental hygiene.

PubMed

Ng, Deborah H L; Marimuthu, Kalisvar; Lee, Jia Jun; Khong, Wei Xin; Ng, Oon Tek; Zhang, Wei; Poh, Bee Fong; Rao, Pooja; Raj, Maya Devi Rajinder; Ang, Brenda; De, Partha Pratim

2018-01-01

In May 2015, we noticed an increase in carbapenem-resistant Acinetobacter baumannii (CRAB) infections in the Medical Intensive Care Unit (MICU). To investigate this, we studied the extent of environmental contamination and subsequent onward clonal transmission of CRAB. We conducted a one-day point prevalence screening (PPS) of the patients and environment in the MICU. We screened patients using endotracheal tube aspirates and swabs from nares, axillae, groin, rectum, wounds, and exit sites of drains. We collected environmental samples from patients' rooms and environment outside the patients' rooms. CRAB isolates from the PPS and clinical samples over the subsequent one month were studied for genetic relatedness by whole genome sequencing (WGS). We collected 34 samples from seven patients and 244 samples from the environment. On the day of PPS, we identified 8 CRAB carriers: 3 who screened positive and 5 previously known clinical infections. We detected environmental contamination in nearly two-thirds of the rooms housing patients with CRAB. WGS demonstrated genetic clustering of isolates within rooms but not across rooms. We analysed 4 CRAB isolates from clinical samples following the PPS. One genetically-related CRAB was identified in the respiratory sample of a patient with nosocomial pneumonia, who was admitted to the MICU five days after the PPS. The extensive environmental colonization of CRAB by patients highlights the importance of environmental hygiene. The transmission dynamics of CRAB needs further investigation.

Resistance of the genome of Escherichia coli and Listeria monocytogenes to irradiation evaluated by the induction of cyclobutane pyrimidine dimers and 6-4 photoproducts using gamma and UV-C radiations

NASA Astrophysics Data System (ADS)

Beauchamp, S.; Lacroix, M.

2012-08-01

The effect of gamma and UV-C irradiation on the production of cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4 PPs) in DNA was investigated to compare the natural resistance of the genome of a Gram-positive bacterium and a Gram-negative bacterium against irradiation. Solution of pure DNA and bacterial strains Listeria monocytogenes and Escherichia coli were irradiated using gamma and UV-C rays. Extracted DNA from bacteria and pure DNA samples were then analysed by ELISA using anti-CPDs and anti-6-4 PPs monoclonal antibodies. The results show that gamma rays, as well as UV-C rays, induce the formation of CPDs and 6-4 PPs in DNA. During UV-C irradiation, the three samples showed a difference in their sensitivity against formation of CPDs (P≤0.05). Pure DNA was the most sensitive while the genome of L. monocytogenes was the most resistant. Also during UV-C irradiation, the genome of L. monocytogenes was the only one to show a significant resistance against formation of 6-4 PPs (P≤0.05). During gamma irradiation, for both types of lesion, pure DNA and the genome of E. coli did not show significant difference in their sensitivity (P>0.05) while the genome of L. monocytogenes showed a resistance against formation of CPDs and 6-4 PPs.

Post-Progression Survival Associated with Overall Survival in Patients with Advanced Non-Small-Cell Lung Cancer Receiving Docetaxel Monotherapy as Second-Line Chemotherapy.

PubMed

Kotake, Mie; Miura, Yosuke; Imai, Hisao; Mori, Keita; Sakurai, Reiko; Kaira, Kyoichi; Tomizawa, Yoshio; Minato, Koichi; Saito, Ryusei; Hisada, Takeshi

2017-01-01

In patients with non-small-cell lung cancer (NSCLC), the effects of second-line chemotherapy on overall survival (OS) might be confounded by subsequent therapies. Therefore, using individual-level data, we aimed to determine the relationships between progression-free survival (PFS) and post-progression survival (PPS) with OS in patients with advanced NSCLC treated with docetaxel monotherapy as second-line chemotherapy. Between April 2002 and December 2014, data from 86 patients with advanced NSCLC who underwent second-line docetaxel monotherapy following first-line treatment with platinum combination chemotherapy were analyzed. The relationships of PFS and PPS with OS were analyzed at the individual level. Spearman rank correlation and linear regression analyses showed that PPS was strongly associated with OS (r = 0.86, p < 0.05, R2 = 0.93), whereas PFS was moderately correlated with OS (r = 0.50, p < 0.05, R2 = 0.21). Performance status at the end of second-line treatment and the number of regimens after progression beyond second-line chemotherapy were significantly associated with PPS (p < 0.05). In patients with advanced NSCLC with unknown oncogenic driver mutations undergoing docetaxel monotherapy as second-line chemotherapy, when compared with PFS, PPS had a stronger association with OS. This finding suggests that subsequent treatment after disease progression following second-line docetaxel monotherapy has a significant influence on OS. © 2017 S. Karger AG, Basel.

The Design, Usability, and Feasibility of a Family-Focused Diabetes Self-Care Support mHealth Intervention for Diverse, Low-Income Adults with Type 2 Diabetes.

PubMed

Mayberry, Lindsay Satterwhite; Berg, Cynthia A; Harper, Kryseana J; Osborn, Chandra Y

2016-01-01

Family members' helpful and harmful actions affect adherence to self-care and glycemic control among adults with type 2 diabetes (T2D) and low socioeconomic status. Few family interventions for adults with T2D address harmful actions or use text messages to reach family members. Through user-centered design and iterative usability/feasibility testing, we developed a mHealth intervention for disadvantaged adults with T2D called FAMS. FAMS delivers phone coaching to set self-care goals and improve patient participant's (PP) ability to identify and address family actions that support/impede self-care. PPs receive text message support and can choose to invite a support person (SP) to receive text messages. We recruited 19 adults with T2D from three Federally Qualified Health Centers to use FAMS for two weeks and complete a feedback interview. Coach-reported data captured coaching success, technical data captured user engagement, and PP/SP interviews captured the FAMS experience. PPs were predominantly African American, 83% had incomes <$35,000, and 26% were married. Most SPs ( n = 7) were spouses/partners or adult children. PPs reported FAMS increased self-care and both PPs and SPs reported FAMS improved support for and communication about diabetes. FAMS is usable and feasible and appears to help patients manage self-care support, although some PPs may not have a SP.

The Design, Usability, and Feasibility of a Family-Focused Diabetes Self-Care Support mHealth Intervention for Diverse, Low-Income Adults with Type 2 Diabetes

PubMed Central

Berg, Cynthia A.; Harper, Kryseana J.; Osborn, Chandra Y.

2016-01-01

Family members' helpful and harmful actions affect adherence to self-care and glycemic control among adults with type 2 diabetes (T2D) and low socioeconomic status. Few family interventions for adults with T2D address harmful actions or use text messages to reach family members. Through user-centered design and iterative usability/feasibility testing, we developed a mHealth intervention for disadvantaged adults with T2D called FAMS. FAMS delivers phone coaching to set self-care goals and improve patient participant's (PP) ability to identify and address family actions that support/impede self-care. PPs receive text message support and can choose to invite a support person (SP) to receive text messages. We recruited 19 adults with T2D from three Federally Qualified Health Centers to use FAMS for two weeks and complete a feedback interview. Coach-reported data captured coaching success, technical data captured user engagement, and PP/SP interviews captured the FAMS experience. PPs were predominantly African American, 83% had incomes <$35,000, and 26% were married. Most SPs (n = 7) were spouses/partners or adult children. PPs reported FAMS increased self-care and both PPs and SPs reported FAMS improved support for and communication about diabetes. FAMS is usable and feasible and appears to help patients manage self-care support, although some PPs may not have a SP. PMID:27891524

Interaction of albumins and heparinoids investigated by affinity capillary electrophoresis and free flow electrophoresis.

PubMed

Mozafari, Mona; El Deeb, Sami; Krull, Friederike; Wildgruber, Robert; Weber, Gerhard; Reiter, Christian G; Wätzig, Hermann

2018-02-01

A fast and precise affinity capillary electrophoresis (ACE) method has been applied to investigate the interactions between two serum albumins (HSA and BSA) and heparinoids. Furthermore, different free flow electrophoresis methods were developed to separate the species which appears owing to interaction of albumins with pentosan polysulfate sodium (PPS) under different experimental conditions. For ACE experiments, the normalized mobility ratios (∆R/R f ), which provided information about the binding strength and the overall charge of the protein-ligand complex, were used to evaluate the binding affinities. ACE experiments were performed at two different temperatures (23 and 37°C). Both BSA and HSA interact more strongly with PPS than with unfractionated and low molecular weight heparins. For PPS, the interactions can already be observed at low mg/L concentrations (3 mg/L), and saturation is already obtained at approximately 20 mg/L. Unfractionated heparin showed almost no interactions with BSA at 23°C, but weak interactions at 37°C at higher heparin concentrations. The additional signals also appeared at higher concentrations at 37°C. Nevertheless, in most cases the binding data were similar at both temperatures. Furthermore, HSA showed a characteristic splitting in two peaks especially after interacting with PPS, which is probably attributable to the formation of two species or conformational change of HSA after interacting with PPS. The free flow electrophoresis methods have confirmed and completed the ACE experiments. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of SiC particle size on the microstructure and properties of cold-sprayed Al/SiCp composite coating

NASA Astrophysics Data System (ADS)

Yu, Min; Hua, Junwei

2017-07-01

The Al5056/SiC composite coatings were prepared by cold spraying. Experimental results show that the SiC content in the composite coating deposited with the SiC powder having an average size of 67 μm (Al5056/SiC-67) is similar to that deposited with the SiC powder having an average size of 27 μm (Al5056/SiC-27). The microhardness and cohesion strength of Al5056/SiC-67 coating are higher than those of the Al5056/SiC-27 coating. In addition, the Al5056/SiC-67 coating having a superior wear resistance because of the coarse SiC powder with a superior kinetic energy contributes to the deformation resistance of the matrix Al5056 particles.

Effect of protective release coatings on the basis of superdispersersed zirconium oxide powder on the formation of gas defects in bronze casting

NASA Astrophysics Data System (ADS)

Martyushev, Nikita V.; Risto, Nikolay A.

2014-10-01

This paper investigates the use of nanopowders in the composition of foundry coatings when casting leaded tin bronzes. Influence of the composition of the applied protective coating on surface finish is studied. The effects of the coatings of the following compositions are compared: non-stick coating (a mixture of low-dispersed chromium oxide powder and heat-treated vegetable oil); non-stick lubricant ASPF-2/RgU on the basis of low- dispersed graphite powder and heat-treated vegetable oil; patent #2297300 (a mixture of superdispersed zirconium dioxide powder with industrial oil). It is demonstrated that application of foundry coatings containing superdispersed metal oxide powders with low thermal conductivity makes it possible to significantly reduce irregularities and eliminate gas porosity on the surface of tin-leaded bronze castings.

Aluminum phosphate coatings

DOEpatents

Sambasivan, Sankar; Steiner, Kimberly A.; Rangan, Krishnaswamy K.

2007-12-25

Aluminophosphate compounds and compositions as can be used for substrate or composite films and coating to provide or enhance, without limitation, planarization, anti-biofouling and/or anti-microbial properties.

Conductive polymer and Si nanoparticles composite secondary particles and structured current collectors for high loading lithium ion negative electrode application

DOEpatents

Liu, Gao

2017-07-11

Embodiments of the present invention disclose a composition of matter comprising a silicon (Si) nanoparticle coated with a conductive polymer. Another embodiment discloses a method for preparing a composition of matter comprising a plurality of silicon (Si) nanoparticles coated with a conductive polymer comprising providing Si nanoparticles, providing a conductive polymer, preparing a Si nanoparticle, conductive polymer, and solvent slurry, spraying the slurry into a liquid medium that is a non-solvent of the conductive polymer, and precipitating the silicon (Si) nanoparticles coated with the conductive polymer. Another embodiment discloses an anode comprising a current collector, and a composition of matter comprising a silicon (Si) nanoparticle coated with a conductive polymer.

Co-electrodeposition of hard Ni-W/diamond nanocomposite coatings

PubMed Central

Zhang, Xinyu; Qin, Jiaqian; Das, Malay Kumar; Hao, Ruru; Zhong, Hua; Thueploy, Adisak; Limpanart, Sarintorn; Boonyongmaneerat, Yuttanant; Ma, Mingzhen; Liu, Riping

2016-01-01

Electroplated hard chrome coating is widely used as a wear resistant coating to prolong the life of mechanical components. However, the electroplating process generates hexavalent chromium ion which is known carcinogen. Hence, there is a major effort throughout the electroplating industry to replace hard chrome coating. Composite coating has been identified as suitable materials for replacement of hard chrome coating, while deposition coating prepared using traditional co-deposition techniques have relatively low particles content, but the content of particles incorporated into a coating may fundamentally affect its properties. In the present work, Ni-W/diamond composite coatings were prepared by sediment co-electrodeposition from Ni-W plating bath, containing suspended diamond particles. This study indicates that higher diamond contents could be successfully co-deposited and uniformly distributed in the Ni-W alloy matrix. The maximum hardness of Ni-W/diamond composite coatings is found to be 2249 ± 23 Hv due to the highest diamond content of 64 wt.%. The hardness could be further enhanced up to 2647 ± 25 Hv with heat treatment at 873 K for 1 h in Ar gas, which is comparable to hard chrome coatings. Moreover, the addition of diamond particles could significantly enhance the wear resistance of the coatings. PMID:26924136

The Influence of the Coating Deposition Process on the Interdiffusion Behavior Between Nickel-Based Superalloys and MCrAlY Bond Coats

NASA Astrophysics Data System (ADS)

Elsaß, M.; Frommherz, M.; Oechsner, M.

2018-02-01

In this work, interdiffusion between two nickel-based superalloys and two MCrAlY bond coats is investigated. The MCrAlY bond coats were applied using two different spraying processes, high velocity oxygen fuel spraying (HVOF) and low-pressure plasma spraying. Of primary interest is the evolution of Kirkendall porosity, which can form at the interface between substrate and bond coat and depends largely on the chemical compositions of the coating and substrate. Experimental evidence further suggested that the formation of Kirkendall porosity depends on the coating deposition process. Formation of porosity at the interface causes a degradation of the bonding strength between substrate and coating. After coating deposition, the samples were annealed at 1050 °C for up to 2000 h. Microstructural and compositional analyses were performed to determine and evaluate the Kirkendall porosity. The results reveal a strong influence of both the coating deposition process and the chemical compositions. The amount of Kirkendall porosity formed, as well as the location of appearance, is largely influenced by the coating deposition process. In general, samples with bond coats applied by means of HVOF show accelerated element diffusion. It is hypothesized that recrystallization of the substrate material is a main root cause for these observations.

Co-electrodeposition of hard Ni-W/diamond nanocomposite coatings.

PubMed

Zhang, Xinyu; Qin, Jiaqian; Das, Malay Kumar; Hao, Ruru; Zhong, Hua; Thueploy, Adisak; Limpanart, Sarintorn; Boonyongmaneerat, Yuttanant; Ma, Mingzhen; Liu, Riping

2016-02-29

Electroplated hard chrome coating is widely used as a wear resistant coating to prolong the life of mechanical components. However, the electroplating process generates hexavalent chromium ion which is known carcinogen. Hence, there is a major effort throughout the electroplating industry to replace hard chrome coating. Composite coating has been identified as suitable materials for replacement of hard chrome coating, while deposition coating prepared using traditional co-deposition techniques have relatively low particles content, but the content of particles incorporated into a coating may fundamentally affect its properties. In the present work, Ni-W/diamond composite coatings were prepared by sediment co-electrodeposition from Ni-W plating bath, containing suspended diamond particles. This study indicates that higher diamond contents could be successfully co-deposited and uniformly distributed in the Ni-W alloy matrix. The maximum hardness of Ni-W/diamond composite coatings is found to be 2249 ± 23 Hv due to the highest diamond content of 64 wt.%. The hardness could be further enhanced up to 2647 ± 25 Hv with heat treatment at 873 K for 1 h in Ar gas, which is comparable to hard chrome coatings. Moreover, the addition of diamond particles could significantly enhance the wear resistance of the coatings.

Co-electrodeposition of hard Ni-W/diamond nanocomposite coatings

NASA Astrophysics Data System (ADS)

Zhang, Xinyu; Qin, Jiaqian; Das, Malay Kumar; Hao, Ruru; Zhong, Hua; Thueploy, Adisak; Limpanart, Sarintorn; Boonyongmaneerat, Yuttanant; Ma, Mingzhen; Liu, Riping

2016-02-01

Electroplated hard chrome coating is widely used as a wear resistant coating to prolong the life of mechanical components. However, the electroplating process generates hexavalent chromium ion which is known carcinogen. Hence, there is a major effort throughout the electroplating industry to replace hard chrome coating. Composite coating has been identified as suitable materials for replacement of hard chrome coating, while deposition coating prepared using traditional co-deposition techniques have relatively low particles content, but the content of particles incorporated into a coating may fundamentally affect its properties. In the present work, Ni-W/diamond composite coatings were prepared by sediment co-electrodeposition from Ni-W plating bath, containing suspended diamond particles. This study indicates that higher diamond contents could be successfully co-deposited and uniformly distributed in the Ni-W alloy matrix. The maximum hardness of Ni-W/diamond composite coatings is found to be 2249 ± 23 Hv due to the highest diamond content of 64 wt.%. The hardness could be further enhanced up to 2647 ± 25 Hv with heat treatment at 873 K for 1 h in Ar gas, which is comparable to hard chrome coatings. Moreover, the addition of diamond particles could significantly enhance the wear resistance of the coatings.

Primordial power spectrum from Planck

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hazra, Dhiraj Kumar; Shafieloo, Arman; Souradeep, Tarun, E-mail: dhiraj@apctp.org, E-mail: arman@apctp.org, E-mail: tarun@iucaa.ernet.in

2014-11-01

Using modified Richardson-Lucy algorithm we reconstruct the primordial power spectrum (PPS) from Planck Cosmic Microwave Background (CMB) temperature anisotropy data. In our analysis we use different combinations of angular power spectra from Planck to reconstruct the shape of the primordial power spectrum and locate possible features. Performing an extensive error analysis we found the dip near ℓ ∼ 750–850 represents the most prominent feature in the data. Feature near ℓ ∼ 1800–2000 is detectable with high confidence only in 217 GHz spectrum and is apparently consequence of a small systematic as described in the revised Planck 2013 papers. Fixing the background cosmological parameters andmore » the foreground nuisance parameters to their best fit baseline values, we report that the best fit power law primordial power spectrum is consistent with the reconstructed form of the PPS at 2σ C.L. of the estimated errors (apart from the local features mentioned above). As a consistency test, we found the reconstructed primordial power spectrum from Planck temperature data can also substantially improve the fit to WMAP-9 angular power spectrum data (with respect to power-law form of the PPS) allowing an overall amplitude shift of ∼ 2.5%. In this context low-ℓ and 100 GHz spectrum from Planck which have proper overlap in the multipole range with WMAP data found to be completely consistent with WMAP-9 (allowing amplitude shift). As another important result of our analysis we do report the evidence of gravitational lensing through the reconstruction analysis. Finally we present two smooth form of the PPS containing only the important features. These smooth forms of PPS can provide significant improvements in fitting the data (with respect to the power law PPS) and can be helpful to give hints for inflationary model building.« less

Relationships between molecular structure and kinetic and thermodynamic controls in lipid systems. Part II: Phase behavior and transformation paths of SSS, PSS and PPS saturated triacylglycerols--effect of chain length mismatch.

PubMed

Bouzidi, Laziz; Narine, Suresh S

2012-01-01

The kinetic phase behavior and phase transformation paths of purified tristearoylglycerol (SSS), 3-palmitoyl-1,2-distearoyl-sn-glycerol (PSS) and 1,2-dipalmitoyl-3-stearoyl-sn-glycerol (PPS) were investigated in terms of polymorphism, crystallization and melting. The details of the phase transformation paths were obtained using the heating cycles of two sets of experiments: (a) cooling rate was varied and heating rate fixed and (b) cooling rate was fixed and heating rate varied. Kinetic effects were manifest in all measured properties, underscoring the complexity of the phase transformation paths for each TAG, and the intricate thermodynamics-molecular relationships. For the first time, XRD data obtained for SSS, PSS and PPS TAGs, cooled at rates higher than 0.5°C/min, suggested the formation of a transient structure similar to the so-called α(2)-phase which has been observed in mixed saturated-unsaturated TAGs quenched from the melt. The more stable phases (β' in PSS and PPS, and β in SSS) were only observed for cooling rates lower than 1.0°C/min. The kinetic and thermodynamic differences observed in the crystallization, structure and melting of SSS, PSS and PPS are proposed to be mainly due to the disturbances introduced at the "terrace" level via methyl-end group interactions, i.e., the missing of two or four CH(2) groups compared to SSS. The symmetrical SSS with a relatively flat "terrace" crystallizes preferably in the most stable β-form. Two missing CH(2) groups at the sn-1 position (PSS) introduces enough structural disturbances to promote the relative prevalence and persistence of the β'-phase, and four missing CH(2) groups at the sn-1 and sn-2 positions (PPS) is relatively too large of a disturbance and therefore favors the α-form. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Managing oral phosphate binder medication expenditures within the Medicare bundled end-stage renal disease prospective payment system: economic implications for large U.S. dialysis organizations.

PubMed

Park, Haesuk; Rascati, Karen L; Keith, Michael S

2015-06-01

From January 2016, payment for oral-only renal medications (including phosphate binders and cinacalcet) was expected to be included in the new Medicare bundled end-stage renal disease (ESRD) prospective payment system (PPS). The implementation of the ESRD PPS has generated concern within the nephrology community because of the potential for inadequate funding and the impact on patient quality of care. To estimate the potential economic impact of the new Medicare bundled ESRD PPS reimbursement from the perspective of a large dialysis organization in the United States. We developed an interactive budget impact model to evaluate the potential economic implications of Medicare payment changes to large dialysis organizations treating patients with ESRD who are receiving phosphate binders. In this analysis, we focused on the budget impact of the intended 2016 integration of oral renal drugs, specifically oral phosphate binders, into the PPS. We also utilized the model to explore the budgetary impact of a variety of potential shifts in phosphate binder market shares under the bundled PPS from 2013 to 2016. The base model predicts that phosphate binder costs will increase to $34.48 per dialysis session in 2016, with estimated U.S. total costs for phosphate binders of over $682 million. Based on these estimates, a projected Medicare PPS $33.44 reimbursement rate for coverage of all oral-only renal medications (i.e., phosphate binders and cinacalcet) would be insufficient to cover these costs. A potential renal drugs and services budget shortfall for large dialysis organizations of almost $346 million was projected. Our findings suggest that large dialysis organizations will be challenged to manage phosphate binder expenditures within the planned Medicare bundled rate structure. As a result, large dialysis organizations may have to make treatment choices in light of potential inadequate funding, which could have important implications for the quality of care for patients with ESRD.

Primary payer status is significantly associated with postoperative mortality, morbidity, and hospital resource utilization in pediatric surgical patients within the United States.

PubMed

Stone, Matthew L; LaPar, Damien J; Mulloy, Daniel P; Rasmussen, Sara K; Kane, Bartholomew J; McGahren, Eugene D; Rodgers, Bradley M

2013-01-01

Current healthcare reform efforts have highlighted the potential impact of insurance status on patient outcomes. The influence of primary payer status (PPS) within the pediatric surgical patient population remains unknown. The purpose of this study was to examine risk-adjusted associations between PPS and postoperative mortality, morbidity, and resource utilization in pediatric surgical patients within the United States. A weighted total of 153,333 pediatric surgical patients were evaluated using the national Kids' Inpatient Database (2003 and 2006): appendectomy, intussusception, decortication, pyloromyotomy, congenital diaphragmatic hernia repair, and colonic resection for Hirschsprung's disease. Patients were stratified according to PPS: Medicare (n=180), Medicaid (n=51,862), uninsured (n=12,539), and private insurance (n=88,753). Multivariable hierarchical regression modeling was utilized to evaluate risk-adjusted associations between PPS and outcomes. Overall median patient age was 12 years, operations were primarily non-elective (92.4%), and appendectomies accounted for the highest proportion of cases (81.3%). After adjustment for patient, hospital, and operation-related factors, PPS was independently associated with in-hospital death (p<0.0001) and postoperative complications (p<0.02), with increased risk for Medicaid and uninsured populations. Moreover, Medicaid PPS was also associated with greater adjusted lengths of stay and total hospital charges (p<0.0001). Importantly, these results were dependent on operation type. Primary payer status is associated with risk-adjusted postoperative mortality, morbidity, and resource utilization among pediatric surgical patients. Uninsured patients are at increased risk for postoperative mortality while Medicaid patients accrue greater morbidity, hospital lengths of stay, and total charges. These results highlight a complex interaction between socioeconomic and patient-related factors, and primary payer status should be considered in the preoperative risk stratification of pediatric patients. Copyright © 2013 Elsevier Inc. All rights reserved.

Medication decision making and patient outcomes in GP, nurse and pharmacist prescriber consultations.

PubMed

Weiss, Marjorie C; Platt, Jo; Riley, Ruth; Chewning, Betty; Taylor, Gordon; Horrocks, Susan; Taylor, Andrea

2015-09-01

Aim The aims of this study were twofold: (a) to explore whether specific components of shared decision making were present in consultations involving nurse prescribers (NPs), pharmacist prescribers (PPs) and general practitioners (GPs) and (b) to relate these to self-reported patient outcomes including satisfaction, adherence and patient perceptions of practitioner empathy. There are a range of ways for defining and measuring the process of concordance, or shared decision making as it relates to decisions about medicines. As a result, demonstrating a convincing link between shared decision making and patient benefit is challenging. In the United Kingdom, nurses and pharmacists can now take on a prescribing role, engaging in shared decision making. Given the different professional backgrounds of GPs, NPs and PPs, this study sought to explore the process of shared decision making across these three prescriber groups. Analysis of audio-recordings of consultations in primary care in South England between patients and GPs, NPs and PPs. Analysis of patient questionnaires completed post consultation. Findings A total of 532 consultations were audio-recorded with 20 GPs, 19 NPs and 12 PPs. Prescribing decisions occurred in 421 (79%). Patients were given treatment options in 21% (102/482) of decisions, the prescriber elicited the patient's treatment preference in 18% (88/482) and the patient expressed a treatment preference in 24% (118/482) of decisions. PPs were more likely to ask for the patient's preference about their treatment regimen (χ 2=6.6, P=0.036, Cramer's V=0.12) than either NPs or GPs. Of the 275 patient questionnaires, 192(70%) could be matched with a prescribing decision. NP patients had higher satisfaction levels than patients of GPs or PPs. More time describing treatment options was associated with increased satisfaction, adherence and greater perceived practitioner empathy. While defining, measuring and enabling the process of shared decision making remains challenging, it may have patient benefit.

Novel biodegradable calcium phosphate/polymer composite coating with adjustable mechanical properties formed by hydrothermal process for corrosion protection of magnesium substrate.

PubMed

Kaabi Falahieh Asl, Sara; Nemeth, Sandor; Tan, Ming Jen

2016-11-01

Ceramic type coatings on metallic implants, such as calcium phosphate (Ca-P), are generally stiff and brittle, potentially leading to the early failure of the bone-implant interface. To reduce material brittleness, polyacrylic acid and carboxymethyl cellulose were used in this study to deposit two types of novel Ca-P/polymer composite coatings on AZ31 magnesium alloy using a one-step hydrothermal process. X-ray diffraction and scanning electron microscopy showed that the deposited Ca-P crystal phase and morphology could be controlled by the type and concentration of polymer used. Incorporation of polymer in the Ca-P coatings reduced the coating elastic modulus bringing it close to that of magnesium and that of human bone. Nanoindentation test results revealed significantly decreased cracking tendency with the incorporation of polymer in the Ca-P coating. Apart from mechanical improvements, the protective composite layers had also enhanced the corrosion resistance of the substrate by a factor of 1000 which is sufficient for implant application. Cell proliferation studies indicated that the composite coatings induced better cell attachment compared with the purely inorganic Ca-P coating, confirming that the obtained composite materials could be promising candidates for surface protection of magnesium for implant application with the multiple functions of corrosion protection, interfacial stress reduction, and cell attachment/cell growth promotion. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1643-1657, 2016. © 2015 Wiley Periodicals, Inc.

Effects of heat treatment on microstructure and mechanical properties of Ni60/h-BN self-lubricating anti-wear composite coatings on 304 stainless steel by laser cladding

NASA Astrophysics Data System (ADS)

Lu, Xiao-Long; Liu, Xiu-Bo; Yu, Peng-Cheng; Zhai, Yong-Jie; Qiao, Shi-Jie; Wang, Ming-Di; Wang, Yong-Guang; Chen, Yao

2015-11-01

Laser clad Ni60/h-BN self-lubricating anti-wear composite coating on 304 stainless steel were heat treated at 600 °C (stress relief annealing) for 1 h and 2 h, respectively. Effects of the phase compositions, microstructure, microhardness, nano-indentation and tribological properties of the composite coatings with and without heat treatment had been investigated systemically. Results indicated that three coatings mainly consist of the matrix γ-(Ni, Fe) solid solution, the CrB ceramic phases and the h-BN lubricating phases. The maximum microhardness of the coatings was first increased from 667.7 HV0.5 to 765.0 HV0.5 after heat treatment for 1 h, and then decreased to 698.3 HV0.5 after heat treatment for 2 h. The hardness of γ-(Ni, Fe) solid solution without heat treatment and after heat treatment 1 h and 2 h were 5.09 GPa, 7.20 GPa and 3.77 GPa, respectively. Compared with the coating without heat treatment, the friction coefficients of the coating after heat treatment were decreased obviously. Effects of the heat treatment time on friction coefficient were negligible, but were significant on wear volume loss. Comparatively speaking, the laser clad self-lubricating anti-wear composite coating after heat treatment for 1 h presented the best anti-wear and friction reduction properties.