Microstructural Modification of TiAl6V4 Alloy to Avoid Detrimental Effects Due to Selective In Vivo Crevice Corrosion.

TiAl6V4 wrought alloy is a standard material used for endoprostheses due to its ideal characteristics in terms of osseointegration. However, the insufficient wear and crevice corrosion resistance of TiAl6V4 are limiting factors that can cause clinical problems. Therefore, the objective of this study was to analyze and identify suitable phases and microstructural states of TiAl6V4 alloy with advantageous implant properties by thermal treatments.

Microstructure-dependent crevice corrosion damage of implant materials CoCr28Mo6, TiAl6V4 and REX 734 under severe inflammatory conditions.

Fretting corrosion is associated with increased risk of premature implant failure. In this complex in vivo corrosion system, the contribution of static crevice corrosion of the joined metal alloys is still unknown. The aim of this study was to develop a methodology for testing crevice corrosion behavior that simulates the physiological conditions of modular taper junctions and to identify critical factors on corrosion susceptibility.

Modulation of Mammalian Cell Behavior by Nanoporous Glass.

The introduction of novel bioactive materials to manipulate living cell behavior is a crucial topic for biomedical research and tissue engineering. Biomaterials or surface patterns that boost specific cell functions can enable innovative new products in cell culture and diagnostics. This study investigates the influence of the intrinsically nano-patterned surface of nanoporous glass membranes on the behavior of mammalian cells.

Effect of deep rolling on subsurface conditions of CoCr28Mo6 wrought alloy to improve the wear resistance of endoprostheses.

Wear of orthopaedic endoprostheses is associated with adverse local and systemic reactions and can lead to early implant failure. Manufacturing determines the initial subsurface microstructure of an alloy that influences the implant's wear behaviour. Therefore, this study aims at generating enhanced wear resistances by a modification of the surface and subsurface microstructure of a CoCr28Mo6 wrought alloy by applying deep rolling.

Recovery from cytomegalovirus infection is associated with activation of peripheral blood lymphocytes.

The number of CD8bright and CD56+ lymphocytes in the peripheral blood and their activation status were monitored by flow cytometry in 23 renal transplant recipients with cytomegalovirus (CMV) infection and were correlated with the virus load (as determined by CMV antigenemia) and clinical symptoms. Recovery from CMV infection coincided with expansion of the CD8bright and CD56+ subsets and with increased expression of the activation marker HLA-DR. Primary infection was associated with activation of both subsets, whereas during secondary infection, mainly CD8bright cells responded.

In-vitro auxin transport in membrane vesicles from maize coleoptiles.

When membrane vesicles from maize (Zea mays L.) coleoptiles are extracted at high buffer strength, a pH-driven, saturable association of [(14)C] indole-3-acetic acid is found, similar to the in-vitro auxin-transport system previously described for Cucurbita hypocotyls. The phytotropins naphthylphthalamic acid and pyrenoylbenzoic acid increase net uptake, pressumably by inhibiting the auxin-efflux carrier.

Molecular basis of auxin-regulated extension growth and role of dextranase.

The first step in the extension growth of the plant cell is a process in which the cell wall becomes ductile or plastic, after which the actual enlargement takes place passively under the influence of turgor. The nature of this process has not been explained, although much research has been carried out concerning it. In the present report, it is shown that a specific enzyme, which is identical or nearly so with dextranase (alpha-1,6-D-glucan 6-glucanohydrolase, EC 3.

Photochemical precipitation of thorium and cerium and their separation from other ions in aqueous solution.

Thorium was precipitated from homogeneous solution by exposing solutions of thorium and periodate in dilute perchloric acid to 253.7 nm radiation from a low-pressure mercury lamp. Periodate is reduced photochemically to iodate which causes the formation of a dense precipitate of the basic iodate of thorium(IV).

Dextranase activity in coleoptiles of Avena.

Ani enzyme activity similar to that of dextranase is associated with coleoptiles of Avena sativa. When subjected to purified dextranase, both the pure natural dextran and the cell walls of the Avena coleoptiles yield isomaltose and isomaltotriose. Thus, the cell walls contain dextrans or dextran-like compounds.

Precipitation from homogeneous solution by photochemical action: determination of thorium.

Thorium was precipitated from homogeneous solution by photochemical reduction of periodate to iodate in a solution containing thorium and perchloric acid, by means of a 2537 A low-pressure mercury vapour lamp. For weighing, the precipitate was redissolved, precipitated once as thorium hydroxide, and finally as thorium oxalate, which was ignited to thorium dioxide. Quantitative results were obtained in the range 35-180 mg of thorium.

The microcrystalline structure of cellulose in cell walls of cotton, ramie, and jute fibers as revealed by negative staining of sections.

With a new technique of negative staining of sections, it has been possible to observe directly, in ultrathin sections under the electron microscope, the original microcrystalline and microfibrillar structure of cellulose as it occurs in living cells. This method has advantages over the study of isolated fibers used so far by others, in that the original arrangement of microfibrils is better preserved, and their collapse into larger fibrillar units is prevented. With this method, the cell walls of ramie, jute, and cotton fibers have been studied.

Precipitation of metal-cupferron complexes from homogeneous solution-II: determination of titanium.

The cupferron complex of titanium has been precipitated by the addition of phenylhydroxylamine and sodium nitrite to a cold acidic solution of the metal. Details of the method are given. Separation of titanium from aluminium, borate, phosphate and vanadate is described.

Precipitation of metal-cupferron complexes from homogeneous solution-I: determination of copper.

The cupferron complex of copper has been precipitated from homogeneous solution by the addition of phenylhydroxylamine and sodium nitrite to a cold, acidic solution containing copper(II) ions. The precipitate can be dried at 90 +/- 5 degrees and weighed without ignition to the oxide. Less than 3 mg of copper can be determined.

X-RAY DIFFRACTION STUDIES OF THE CRYSTALLINE STRUCTURE OF THE AVIAN EGG SHELL.

From x-ray studies, it is concluded that the avian egg shell is composed of calcium carbonate in the calcite modification. In the main portion (crystalline layer) the calcite occurs in large crystalline areas oriented with the hexagonal axis (17.6 A) inclined at 28 to 16 degrees from the normal of the shell surface.