Strength retention of self-reinforced,absorbable polyglycolide rods in hydrolytic environment

Absorbable polyglycolide suture fibers were sintered with the compression molding techniques to cylindrical rods at temperatures between 205°C and 232°C for 3–5 min with final pressures of 50–80 N/mm². The cylindrical rods had nominal diameters between 1.5–4.5 mm and a length of 50 mm. The initial bending moduli and the initial bending strengths of the rods were between 9–15 GPa and 220–430 MPa, respectively. The shear strengths of the rods were between 165–255 MPa. The hydrolytic loss of mechanical strength of the above self-reinforced, absorabable polyglycolide rods were studied in phosphate buffer at 37°C and 77°C. It was found that the rate of strength loss decreases with the increasing diameter of the rods. On the other hand, the rate of strength loss increases when the temperature of the buffer solution is raised. The strength, retention time at 37°C was between 7–10 weeks showing that the loss of mechanical strength of self-reinforced polyglycolide rods occurs more rapidly in vivo than in vitro.     

Detection of irregularities in regular patterns

Regular patterns, as defined in this study, are found in areas of industry and science, for example, halftone raster patterns used in the printing industry and crystal lattice structures in solid state physics. The need for quality inspection of products containing regular patterns has aroused interest in the application of machine vision for automatic inspection. Quality inspection typically corresponds to detecting abnormalities, defined as irregularities in this case. In this study, the problem of irregularity detection is described in analytical form and three different detection methods are proposed. All the methods are based on characteristics of the Fourier transform to compactly represent regular information. The Fourier transform enables the separation of regular and irregular parts of an input image. The three methods presented are shown to differ in their generality and computational complexities.     

Oxidative Inorganic Multilayers for Polypyrrole Film Generation

A controlled nanoscale fabrication of conducting polymer films sets severe requirements for the preparation method and substrate. A new and versatile approach for producing thin polypyrrole films on a variety of surfaces is presented. Purely inorganic thin films are first prepared from poly(metaphosphate) and tetravalent metal ions using a sequential layer‐by‐layer technique. Redox‐active cerium(IV) polyphosphate multilayer and redox‐inactive zirconium(IV) and hafnium(IV) polyphosphate multilayers are prepared. Cerium‐based polyphosphate films grow exponentially with the number of layers but multilayers containing zirconium or hafnium exhibit a linear buildup process. All the studied systems produce relatively smooth films with initial bilayer thickness less than 2 nm. The cerium(IV) containing film is redox‐active, which is shown by its capability to form a polypyrrole layer on its surface by oxidation of pyrrole monomers in the adjacent aqueous solution. This is a general method to produce thin oxidative films of arbitrary size and form on a wide variety of surfaces.     

Zero-Forcing Spatial Interweave with Greedy Scheduling

In this work, the effect of the multipath on the capacity and the interference statistics of the sectors of the highways cigar-shaped W-CDMA microcells is studied. A model of five microcells is used to analyze the uplink. The capacity and the interference statistics of the microcell are studied for different antenna sidelobe levels and different sector ranges. In the study, imperfect power control and limited transmitted power are assumed. Users are assumed to be within equally spaced buses and cars. The uplink capacity of the sector is studied assuming three types of services, namely, voice, 3G data and 3.75G data (representing the High Speed Uplink Packet Access). It is shown that, the sector uplink capacity depends on the buses and cars density within the sector. The capacity is also given as a function of the number of buses and cars within the sector.     

Computational fractal geometry with WFA

We define two measures of “fractalness” of gray-tone images: the degree of self-similarity and the gray-tone fractal dimension as a generalization of Minkovski dimension of compact sets. We show how to compute both these measures from the WFA-representation of a gray-tone image. Since we have developed a WFA-inference algorithm which computes a good approximation of any gray-tone image we can compute a close approximation of both our measures of fractalness for any gray-tone image. Received: 15 November 1994 / 6 October 1995     

Novel luminescent samarium(III) chelates

A series of new stable, luminescent samarium(III) chelates were synthesized and their photophysical properties were measured. The iodoacetamido activated chelate coupled to a peptide was used in a caspase-3 assay.     

On light attenuation in inhomogeneous colour centre layers

A procedure is presented how to estimate light attenuation in an inhomogeneous photosensitive layer. As an example the behaviour of radiation coloured NaCl crystals under light exposure is described.     

Serious storytelling – a first definition and review

Multimedia Tools and Applications - In human culture, storytelling is a long-established tradition. The reasons people tell stories are manifold: to entertain, to transfer knowledge between...     

Flavonoids and other phenolic compounds in Andean indigenous grains: Quinoa (Chenopodium quinoa), kañiwa (Chenopodium pallidicaule) and kiwicha (Amaranthus caudatus)

The amount of phenolic acids, flavonoids and betalains in Andean indigenous grains, quinoa (Chenopodium quinoa), kañiwa (Chenopodium pallidicaule) and kiwicha (Amaranthus caudatus), was determined. The total amount of phenolic acids varied from 16.8 to 59.7 mg/100 g and the proportion of soluble phenolic acids varied from 7% to 61%. The phenolic acid content in Andean crops was low compared with common cereals like wheat and rye, but was similar to levels found in oat, barley, corn and rice. The flavonoid content of quinoa and kañiwa was exceptionally high, varying from 36.2 to 144.3 mg/100 g. Kiwicha did not contain quantifiable amounts of these compounds. Only one variety of kiwicha contained low amounts of betalains. These compounds were not detected in kañiwa or quinoa. Our study demonstrates that Andean indigenous crops have excellent potential as sources of health-promoting bioactive compounds such as flavonoids.