bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Ion Implantation on Protein Adsorption onto Silicone Rubber
Authors: Suzuki Yoshiaki , Kusakabe Masahiro , Iwaki Masaya , Kusakabe Kiyoko , Akiba Hiromichi , Suzuki Masaaki 
Published: March 2011

AbstractA study has been made on the surface wettability, atomic ratio, chemical structure, chemical bonding states and plasma protein adsorption of ion implanted silicone rubbers. C+-, N2+-, 02+-, Ar+- and Na+-ion implantations were performed at an energy of 150 keV at room temperature. The doses ranged from 1x1012 to 1x1017 ions/cm2. Ion implantation caused the surface roughness to increase by 1–5 times. Surface wettability was estimated by means of a sessile drop method using water. With increasing ion dose, the contact angle of water decreased from 98.9° to 48.5°. However, if the sample was in the air, the contact angle of water returned to its initial valve in time elapsed. The results of XPS measurements showed that implanted elements were incorporated in a gaussian like distribution and host elements were redistributed in the polymer matrix. No change of binding energies of 01s, CIS, Si2p and Si2p can be observed upon ion implantation. Results of FT-IR-ATR showed that C+-, N2+-, 02+-, and Ar+-ion implantation decomposed the original chemical bonds to form the new radicals. The amounts of new radicals are related to doses of implanted ions. In contrast, Na+-ion implantation hardly formed new radicals. The amount of albumin adsorbed onto 02+-, Ar+-, N2+-, and C+- ion implanted silicone is less than that on unimplanted specimens, but more fibrinogen is adsorbed. Na+-ion implantation produced an increase in the amount of adsorbed albumin as the dose increased. In summary, Na+ion implantation produces effects that are attributable to the additional implanted constituent in the surface of the silicone, and 02+-, N2+-, C+-, and Ar+-ion implantations primarily cause radiation effects on silicone rubber.
Ion Implanted Glassy Carbon - Comparison Wear Testing with Pyrolytic Carbon
Authors: Pollock John T. A. , Wielunski Leszek S. 
Published: March 2011

AbstractComparative wear data for unimplanted and implanted (50 keV, 5 × 1015 N+ cm−2) glassy carbon (GC) and pyrolytic carbon (PC) are reported. The implanted GC is about 120 times more resistant to diamond abrasion than unimplanted GC and at least 10 times more resistant than PC. In sliding tests, using a ruby ball as the abrader, the implanted GC is almost unaffected for the conditions employed (50 g load, 30,000 revs) compared with the unimplanted GC and unimplanted PC each of which endured measurable wear. The reasons for the enhancement of wear resistance and the ease with which 1–2 μm thick layers may be produced are discussed.
Biocorrosion Studies of Gold and Rhodium Ion Implanted Titanium and Ti-6Al-4V Alloy
Authors: Lee In-Seop , Buchanan R. A. , Williams J. M. 
Published: March 2011

AbstractConcern continues over the possible long-term biological effects of corrosion products released by degradation of metallic surgical implant materials in the human body. One approach to improve long-term biological performance involves surface modifications to significantly reduce degradation rates. Fundamentally, the elements with lowest driving forces (lowest ΔG functions) for corrosion in aqueous solutions over a wide pH range are the noble metals. With regard to surface-modifications, one of the most effective methods is through ion implantation.In the present on-going study, static in vitro corrosion properties of noble-metal ion-implanted surgical Ti-6Al-4V and commercially-pure(CP) Ti are being investigated in nonpassivating acid and passivating saline solutions. It was postulated that during the early stages of corrosion (or during a corrosion pretreatment) the implanted noble metal would enrich at the surface and significantly reduce subsequent corrosion rates. Thus far, the effects of ion-implanted Au and Rh have been studied, with mixed results. The Au implanted material yielded early benefits, but the enhanced corrosion resistance deteriorated with time, probably because the Au, during the enrichment stage, was not adequately adherent to the substrate. On the other hand, the observed behavior for the Rh implanted material appeared to follow the postulated mechanism, with both initial and time-dependent improvements in corrosion resistance.
Cell Adhesion to Ion Implanted Titanium
Authors: Grabowski K. S. , Gossett C. R. , Young F. A. , Keller J. C. 
Published: March 2011

AbstractThis preliminary investigation evaluates the influence of ion implantation on tissue adhesion by measuring the tendency of fibroblasts to attach to the surface of ion implanted Ti. For this work, polished specimens of commercially pure Ti were implanted with ions of Ti, Ca, C, or N to produce a surface concentration of the implanted element up to about 25 at. %. Unimplanted and ASTM treated Ti, and tissue culture plate specimens were prepared as controls. Specimens were sterilized, then exposed for 15 min. to a culture medium containing about 100,000 fibroblasts. The solution and loose fibroblasts were rinsed away and the fibroblasts counted to determine those left attached. The influence of the different implantation protocols on fibroblast adhesion to Ti will be described. Analysis of the structure and composition of the ion implanted surfaces was obtained by scanning electron microscopy, x-ray photoelectron spectroscopy, and elastic backscattering spectrometry of energetic He ions.
Complement Activation Resulting from Blood-Material Interactions
Authors: Johnson Richart J. , Chenoweth Dennis E. 
Published: March 2011

AbstractRecently there has been a growing awareness of the importance of the interactions of the human complement system with biomaterials which largely stems from the understanding that complement-materials interactions may result in the production of inflammatory mediators, termed C3a and C5a anaphylatoxins, that can produce significant pathopysiologic alterations in the exposed patient. This presentation will review studies of complement activation produced by various hemodialysis membranes. our current data suggests that hemodialysis membranes may be roughly divided into three categories. The first type of membrane displays a high complement-activating potential as judged by measurements of C3a antigen levels produced during dialysis. These membranes also liberate sufficient quantities of C5a to induce both significant granulocytopenia and cardiopulmonary effects. The second group of membranes exhibits a moderate capacity to activate complement, with the amount of C3a antigen produced by these devices being about half that seen with the highly activating dialyzers. Dialyzers in this intermediate group produce only enough C5a to provoke a modest degree of leukopenia and they generally fail to induce cardiopulmonary manifestations. The third type of device fails to produce significant amounts of either free C3a or C5a and does not produce significant granulocytopenia. Factors that could affect the propensity of a material to activate complement include the density and type of surface nucleophiles, and the presence of surface dcarge which may facilitate the interaction of regulatory components and the adsorbtion of both active and bystander proteins.
Plasma Protein Fractionation by Membrane Filtration in Therapeutic Plasmapheresis
Authors: Horiuchi Takashi , Malchesky Paul S. , Nosé Yukihiko 
Published: March 2011

AbstractSynthetic polymer membranes which have a nominal pore size (NPS) of 0.03 to 10 microns were evaluated at varying filtration temperatures to separate pathologic macromolecules such as immune complexes, cryoprecipitable proteins and low density lipoproteins (LDL) from essential plasma proteins. At low temperatures (4 to 10°C) cryoprecipitable proteins were selectively removed from cryoglobulinemic plasmas with membranes of 3 micron NPS. However, severe membrane plugging occurred with membranes of smaller pore sizes. In addition, decreased albumin sieving occurs. Above 37°C, increased albumin sieving and prolonged membrane plugging occurs. In the selective removal of low density lipoproteins from hypercholesterolemic plasmas, membranes with NPS of 0.03 microns were found to be suitable at high operating temperatures. Given the proper combination of membrane and temperature control, disease related pathological macromolecules can be treated effectively by selective macromolecule removal.
ProsorbaRTreatment Column: A Device that Removes Circulating Immune Complexes (CIC), IgG, and Autoimmune Antibodies From Patient Plasma
Authors: Balint Joseph P. , Jones Frank R. , Snyder Harry W. ,   Prosorba Column Clinical Trial Group.
Published: March 2011

AbstractSelective removal of molecular moieties from plasma of patients can result in tumor regression, auto-antibody clearance, and immune modulation. The ProsorbaRColumn consists of highly purified protein A isolated from Staphylococcus and covalently linked to inert silica housed in a polycarbonate device. Protein A acts as an immunoadsorbent to selectively remove immunoglobulin G (IgG) and IgG containing CIC via specific binding to the Fc fragment of IgG. Columns were sterile, disposable devices that remove approximately one gram of IgG from plasma per treatment. As part of a multicenter clinical trial, 8 of 22 (36%) end stage breast cancer patients exhibited objective antitumor responses. Treatment of 24 patients with immune thrombocytopenia resulted in 14 (58%) of patients having objective increases in platelet counts and clearance or significant reduction of anti-platelet antibody. The mechanism of action of this device is unknown at present but may be selective removal of IgG and CIC, and activation of factors such as the complement system which results in enhanced reticuloendothelial system (RES) clearance of CIC. In addition, immune modulation may result due to the stimulation of anti-idiotypic antibodies and selective clonal deletion of auto-antibody producing lymphocyte sub-populations.
Plasticizer Interaction with Stored Blood Produces a Toxic Metabolite, Mono(2-Ethylhexyl)Phthalate
Authors: Rock G. , Labow R. S. , Franklin C. , Burnett R. , Tocchi M. 
Published: March 2011

AbstractMost medical devices utilized in blood storage and transfusion, as well as in many medical and surgical procedures, are manufactured with polyvinylchloride (PVC) plastic containing the plasticizer di(2-ethylhexyl)phthalate (DEHP). During exposure of blood to the plastic surface, the DEHP is leached into the plasma where it is converted to mono(2-ethylhexyl)phthalate (MEHP) by a plasma enzyme in vivo or ex vivo during storage in plastic containers. The toxic effects of MEHP when infused into rats were investigated. The amount of MEHP infused was based on MEHP levels found in a variety of stored blood products (>6 ug/mL in red cell concentrates) and values actually measured during exchange transfusion (5 ug/mL) and cardiopulmonary bypass surgery (2.7 ug/mL). When the circulating level of MEHP in the rat's blood was >125 ug/mL, a greater than 50% decrease in heart rate and blood pressure was observed. This represents a margin of safety of only 25 fold higher than levels measured in humans during exchange transfusions. Although DEHP and MEHP have low oral toxicity, acute exposure by infusion may have lethal effects.
Peripheral Neve Regeneration in Vivo with Tubular Prostheses
Authors: Madison Roger 
Published: March 2011

AbstractWe have developed a quantitative model which allows assessment of the number of primary motor and sensory neurons which regenerate an axon through a tubular prosthesis bridging a 4–5 mm gap of peripheral nerve (1). Labeled somas of motor and sensory neurons are quantified following retrograde transport of horseradish peroxidase (HRP) applied to the distal stump beyond the bridged transection site. The number of myelinated axons at mid-guide level is also quantified. We have studied biodegradable and nin-biodegradable materials as well as the effects on nerve regeneration of basement membrane materials, and specific proteins added to the nerve guide., Adding a laminin-oontaining gel (Matrigel, Collaborative Research, MA) to the lumen of polyethylene tubes increases the rate of nerve regeneration as well as the maximum distance that can be successfully bridged. Similar effects are seen with collagen-based nerve guides when the laminin-cxitaining gel is incorporated into the tube wall. Addition of highly purified acidic fibroblast growth factor (aFGF) to the lumen of polyethylene tubes filled with collagen significantly increases the number of myelinated axons at mid-tube level and the number of primary sensory neurons labeled with HRP.We coxpared collagen-based nerve guides of different wall porosities. Tubes freely permeable to bovine serum albumin (BSA) contain significantly more myelinated axons (4 week survival) than identical collagen tubes permeable to glucose-size molecules. These and additional experiments demonstrate that manipulation of the extracellular microenvironment of regenerating PNS axons can significantly enhance the early regenerative response.
Improvement and Use of Empirical Estimates of 29Si Chemical Shifts in Zeolites
Authors: Newsam J. M. , Melchior M. T. , BEYERLEIN R. A. 
Published: March 2011

Abstract29Si chemical shifts, δ, are for aluminosilicate zeolites expressed as δSi-4Al (which can be estimated from the T-O-T angles observed crystallographically) plus terms involving b1 and b2, the quantitative influences of first and second neighbor aluminum atoms. The former, b1, is assumed to be the sum of a fixed electrostatic component, α, and a framework-specific angular term, β(0 < β < 0.9 ppm), that reflects the generally smaller Si-O-Al angles compared to Si-O-Si. The compositional dependence of δ is approximated by an equal influence, b2, per added second neighbor aluminum atom, the concentration of which is assumed to vary linearly with composition. Values of δS-nAl; n=0-3 for representative L (LTL-framework) and omega (MAZ) zeolites calculated on this basis agree well with those observed. Applying this description of the compositional dependence to as-synthesized and dealuminated CSZ-1 zeolites enables the measurement of framework aluminum contents in this four T-site case.
Synthesis and Structural Characterization of a Hydrated Gallosilicate Zeolite with the Nat-Framework
Authors: Xie D. , Newsam J. M. , Yang J. , Yelon W. B. 
Published: March 2011

AbstractGallosilicate NAT-framework zeolites have been synthesized from Na2O:TMA2O:Ga2O3:SiO2:H2O gels and characterized by chemical analysis and powder X-ray diffraction. The structure of a hydrated material (Orthorhombic, Fdd2, a = 18.423(4) Å, b = 18.826(3) Å, c = 6.652(1) Å) was determined using powder neutron diffraction. The framework Si:T ratio, Si-Ga segregation and non-framework cation and water configurations are similar to those in the analogous aluminosilicates. The geometrical effects of framework gallium substitution are consistent with those observed for other zeolite framework topologies.
The Effect of Support Composition on Platinum Crystallite Agglomeration in Oxygen
Authors: Morrissey Michael F. , Kitazumi Shoko , Hicks Robert F. 
Published: March 2011

AbstractThe effects of temperature of oxygen exposure on metal dispersion were determined for platinum deposited on Al2O3, ZrO2, 12 wt% Y2O3–ZrO2, and MgO. Platinum on zirconia and on magnesia showed higher thermal stability than platinum on alumina.
Mössbauer Analysis of Iridium in Pt-Ir/SiO2 Catalysts
Authors: Sawicki J. A. , Wagner F. E. , Rolston J. H. 
Published: March 2011

AbstractThe state of iridium in highly dispersed bimetallic Pt-Ir catalysts supported on amorphous silica was studied by 193Ir Mössbauer spectroscopy, after deposition via ion exchange, as well as after calcination, reduction in hydrogen, and on exposure to carbon monoxide. Characteristic patterns and relative contributions of adsorbed [Ir(NH3)5Cl] complexes, IrCl3, IrO2 and Pt-Ir alloy particles have been identified. The composition of bimetallic particles indicates a strong tendency for segregation of Pt and Ir.
Adsorption and Acidic Properties of Clays Pillared With Oxide Sols
Authors: Yamanaka S. , Nishihara T. , Hattori M. 
Published: March 2011

AbstractInterlayers of montmorillonite were pillared with TiO2, SiO2-TiO2and SiO2-Fe2O3sols. The pillared structures were thermally stable at least up to 500°C and retained unusually large basal spacings in the range of 24–45Å and surface areas as high as 300–500 m2/g. The TiO2pillared clay showed Type IV adsorption isotherm for nitrogen. Although SiO2-TiO2and SiO2-Fe2O3pillared clays had basal spacings much larger than that of TiO2pillared clay, these mixed oxide pillared clays had small pores and exhibited Type I isotherm. The acidic strength distributions were determined by a titration method using n-butylamine and Hammett indicators. All of the pillared clays had large acidities, but the acidic strength decreased in the following order: TiO2- SiO2» SiO2-Fe2O3pillared clays. Temperature-programmed desorption (TPD) spectra of ammonia were measured and interpreted in relation to the acidity distribution. Infrared spectra of pyridine adsorbed on TiO2pillared clay indicated that the acidity predominantly arises from Lewis acid sites.
Study of Model Copper-Based Catalysts by Simultaneous Differential Scanning Calorimetry, X-Ray Diffraction and Mass Spectrometry
Authors: Newman Robert A. , Blazy Joseph A. , Fawcett Timothy G. , Whiting Larry F. , Stowe Robert A. 
Published: March 2011

AbstractRecently, a new materials characterization instrument and technique employing simultaneous differential scanning calorimetry/X-ray diffraction/mass spectrometry (DSC/XRD/MS) have been developed at Dow. Use of this technology can be illlustrated by the study of various materials such as polymers, organics/pharmaceuticals, inorganics, and catalysts.Presented here is the use of the DSC/XRD/MS instrument to study the thermostructural behavior of four model copper-based catalyst systems during activation and regeneration. The instrument allows simultaneous generation of thermal, structural and chemical data in real-time during temperature programmed analysis and provides useful insights into the chemical and physical processes occurring. In addition, the calorimetry data yield qualititative information on the magnitude and rate of heat flow, while the diffraction data provide structural dynamics of reduction, oxidation and crystallite growth.The results of this study conclusively show cuprous oxide as an intermediate in the reduction of the copper oxide portion of each of the model catalysts. However, such features as the onset temperature and copper surface area varied widely among the four catalysts in response to the same chemical event conducted under similar experimental conditions. On the other hand, oxidation runs on the reduced catalysts were all similar to each other, first producing cuprous oxide from copper metal over a broad range of temperature, followed by the oxidation of cuprous oxide to copper oxide at even higher temperatures.
Carbon Formation on Supported Metal Catalysts
Authors: Baker R. T. K. 
Published: March 2011

AbstractThe potential for carbon formation exists in any system in which hydrocarbons undergo thermal decomposition. It is well known that certain metals can increase the carbon yield by catalyzing the growth of both filamentous and graphitic types of deposit. The highest catalytic activity for carbon deposition is exhibited by the ferromagnetic metals and in particular, iron.We have used a combination of controlled atmosphere and high resolution electron microscopy techniques to study the formation of the various types of carbon on metal surfaces. In this paper the emphasis is placed on the fundamental aspects surrounding the growth of filamentous carbon. The qualitative and quantitative data obtained from these studies have enable us to develop a mechanism for the growth of filamentous carbon and also provided insights into methods of inhibiting the growth of this form of carbon. Continuous observation of many filamentous carbon growth sequences has shown that both the addition of a second metal to the catalyst and also the strength of the metal-support interaction can have a profound effect on the mode by which carbon filaments grow.
Diffusion in High Occupancy Zeolites
Authors: Wei James 
Published: March 2011

AbstractDiffusion of small molecules in zeolites most often takes place in the configurational diffusion region, where the molecular diameter is approximately the same or slightly greater than the channel diameter. Since two molecules may not pass each other in a pore, the random walk based diffusion equation does not apply under high occupancy conditions in zeolites with one-dimensional pores.For zeolites with multi-dimensional pores, such as ZSM-5 and A, one sometimes encounters the counter-intuitive result that diffusivity dramatically rises with occupancy. There are two explanations for this behavior: one from irreversible thermodynamics and the Darken equation, which predicts that diffusivity will always rise with occupancy; the other from a Markov model of random activated jumps between low energy positions, such as pore crossings, which predicts that diffusivity will increase with occupancy if the activation energy of diffusion decreases with occupancy– such as due to swelling.
Temperature Dependence of Copper (II) Catalyzed Oxidation of Propylene on X Zeolite: Relation To Copper (II) Migration
Authors: Yu Jong-Sung , Kevan Larry 
Published: March 2011

AbstractThe copper(II) catalyzed oxidation of propylene on CuK-X zeolite was studied over the temperature range of 150 to 400°C in a flow system. Arrhenius activation energies could be obtained at less than 30%conversion from 160 to 210°C and were found to decrease with increasing copper(II) content. These results are correlated with electron spin resonance studies of the migration of copper(II) within the zeolite lattice at the reaction temperature. The change in activation energy with copper(II) content shows that a substantial part of the total activation energy is due to copper(II) migration.
Active Sites in Oxide-Promoted Metal Catalysts – Evidence for the Significance of Perimeter Sites in AlOx and MnOx/Ni(lll) Catalysts
Authors: Zhao Yong-Bo , Lin Tzer-Shen , Chung Yip-Wah 
Published: March 2011

AbstractMnOx (0.2 < × < 0.5) and AlOx (0.5 < × < 1.1) /Ni(lll) model catalysts were prepared by depositing the oxides onto clean Ni(111) surfaces under ultrahigh vacuum conditions, with the average oxide coverage varying from 0 to 1.3 monolayers (ML) for MnOx and 0 to 2.8 ML for AlOx. CO chemisorption over these catalysts at 200 K was used to titrate different adsorption sites. Thermal desorption showed the usual prominent CO desorption peak at 415 K from the clean Ni(111) surface. This 415 K peak decreases with increasing oxide coverage in an almost linear fashion, indicating a siteblocking effect by the oxide. At the same time, a new thermal desorption peak appears at 305 K from MnOx/Ni(111) and 300 K from AlOx/Ni(111), reaching maximum intensity at some intermediate oxide coverage. For MnOx/Ni(111), this coincides with the appearance of a new C-0 stretching mode at 1620 cm−1, which disappears upon heating the surface to 325 K for a few minutes, suggesting that both the 305 K thermal desorption peak and the 1620 cm−1 loss peak represent the same adsorbed CO state. This is attributed to CO adsorbed on MnOx/Ni perimeter sites. Results from Monte Carlo simulation and scanning tunneling microscopy are presented and compared with CO chemisorption data. The significance of perimeter sites in strong metal-support interaction is discussed.