Russia's Debt Crisis and the Unofficial Economy

Russia's foreign debt problems worsened substantially after the financial crisis of 1998. The paper focuses on the key role of the government in servicing foreign debt and promoting institution building by showing how foreign debt influences the choice between official and unofficial taxation. The enterprise sector is assumed to reallocate its resources between domestic investment and capital flight. It is discussed under which conditions debt rescheduling may create incentives for the government to promote institution building. The results of this paper shed light on the conditions under which the recent agreement with the London Club to write off substantial amounts of former Soviet debt can be successful.Foreign debt, debt restructuring, Russian Federation

Russlands Aufschwung in Gefahr

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Strontium potently inhibits mineralisation in bone-forming primary rat osteoblast cultures and reduces numbers of osteoclasts in mouse marrow cultures

The basic mechanisms by which strontium ranelate acts on bone are still unclear. We show that an important action of strontium salts is to block calcification in cultures of osteoblasts, the bone-forming cells. These results suggest that strontium treatment could have previously overlooked effects on bone

Design Enhancement of Biomedical Scaffolds Made By Selective Laser Melting

Selective laser melting (SLM) is increasingly used to fabricate biomedical scaffolds. However, the intrinsic specifications of the process such as laser spot size, layer thickness, and particle size limit the production accuracy, altering the geometrical characteristics and mechanical properties of the scaffolds. This work attempts to assess and improve the mechanical properties of TiAl6V4 biomedical scaffolds by eliminating/modifying the sharp and thin nodes (as the main source of stress concentrations and lowering the mechanical properties). This is carried out through a gradual increase of the beam (strut) thickness around the nodes where corresponding struts meet. The compression performance of these scaffolds was assessed and compared to common examples (unaltered struts) and to scaffolds designed with thicker struts in the centre of the beams (demonstrating the largest contrast). The findings prove that the thickening of the nodal points improves the strain distribution while maintains the mechanical properties at an identical solid volume fraction. This can be used to improve the scaffold design by a gradual strut thickness (in a comparable volume fraction) for an improved bio-mechanical performance.Mechanical Engineerin

Russlands Wirtschaftspolitik setzt auf Investitionen

Russlands wirtschaftlicher Start in das neue Jahrtausend scheint gelungen zu sein: Bruttoinlandsprodukt und Investitionen zeigen einen deutlichen Aufwärtstrend, die Einnahmen des Staates nehmen zu, die Inflation ist moderat, die Währung erscheint hinreichend stabil, und die Zahlungsbilanzsituation hat sich deutlich verbessert. Die starke reale Abwertung des Rubels nach der Währungskrise des Jahres 1998 sowie die Anstiege der Ölpreise stehen sicherlich hinter diesen Entwicklungen. Eine wichtige Rolle spielte aber auch die deutliche Verbesserung der Finanzlage des Unternehmenssektors aufgrund einer drastischen Absenkung des Reallohnniveaus. Zudem ist im wichtigen Bereich der institutionellen Rahmenbedingungen, deren Unzulänglichkeit immer wieder beklagt wurde, ein vorsichtiger Umschwung zu verzeichnen. Präsident Putin hat einen „starken Staat" und die Einhaltung des bestehenden Rechts zu einem Primat seiner Politik gemacht. Es gibt Hinweise darauf, dass eine gewisse Furcht vor staatlichen Sanktionen bei einigen Akteuren bereits zu Verhaltensanpassungen in Form einer prophylaktischen Einhaltung geltender Regeln geführt hat. In diesem Sinne trägt die jüngste wirtschaftliche Erholung schon die Handschrift der neuen politischen Führung. Die Unsicherheit über den zukünftigen wirtschaftspolitischen Kurs Russlands ist daher weniger groß, als häufig vermutet wird. Unsicherheit besteht aber in der Frage, wie die neue Rolle des starken Staates konkret ausgestaltet werden wird. Eine Stärkung des Staates kann nämlich einerseits bedeuten, dass bestehende rechtliche Regelungen konsequent angewandt werden und der institutionelle Rahmen insgesamt verbessert wird. Eine solche Entwicklung wäre aus ordnungspolitischer Sicht zu begrüßen. Andererseits kann die verstärkte Einflussnahme des Staates auf die Wirtschaft aber auch dahingehend interpretiert werden, dass in einzelwirtschaftliche Entscheidungsprozesse direkt eingegriffen wird. Dies wäre mit der Schaffung eines marktwirtschaftlichen Umfelds nicht kompatibel. Bereits erfolgte Eingriffe sowie Pläne, die Investitionstätigkeit stärker zu regulieren, weisen gleichwohl in diese Richtung. Grundsätzlich stehen die Chancen, dass Russland seine positive wirtschaftliche Entwicklung fortsetzt, derzeit nicht schlecht. Erstmals seit Jahren hat eine Regierung politisch die Chance, ihre Konzepte auch umzusetzen; die außenwirtschaftlichen Rahmenbedingungen sind günstig. Für das laufende Jahr ist zu erwarten, dass diese positiven Impulse tragen, so dass ein Wachstum von 5 Prozent nicht überraschen würde. Die Inflation dürfte sich in einer Größenordnung von rund 15 Prozent bewegen. Über kurz oder lang werden sich jedoch die Widersprüche des wirtschaftspolitischen Konzepts abträglich auf das Wirtschaftswachstum auswirken. Die entscheidende Frage wird dann lauten, ob der weiteren Schaffung marktwirtschaftlicher Rahmenbedingungen der Vorzug gegeben oder nur versucht wird, den interventionistischen Reflexen mit größerer Härte zum Erfolg zu verhelfen. Noch sind die äußeren Bedingungen so, dass der Schaden aus der gleichzeitigen Verfolgung dieser inkompatiblen Wege nicht sichtbar wird. Diese Bedingungen könnten sich jedoch rasch ändern. --

Increased serum strontium levels in dialysis patients: An epidemiological survey

Increased serum strontium levels in dialysis patients: An epidemiological survey.BackgroundWe previously reported on increased bone strontium levels in dialysis patients with osteomalacia versus those presenting other types of renal osteodystrophy. A causal role of strontium in the development of osteomalacia was established in a chronic renal failure rat model.MethodsTo further elucidate the latter issue and to find out whether dialysis patients from particular centers/countries are at an increased risk for strontium accumulation, a worldwide multicenter study was established. In total, 834 patients from 34 dialysis centers in 23 countries were included. In each of the patients, a serum sample was taken for strontium determination, and water and dialysate samples were taken at the various steps of the water purification process. For each patient clinical data and for each center dialysis modalities were recorded.ResultsStrontium levels in serum of dialysis patients showed major differences between the various centers, ranging from mean values of 25 ± 8 μg/liter in the center with the lowest level up to 466 ± 90 μg/liter in the center with the highest concentration. It is of interest that these high levels were mainly found in developing countries. Furthermore, our data point toward a role of the final dialysate in the accumulation of the element, as indicated by the strong correlation (r = 0.74, P < 0.001) between mean serum and dialysate strontium levels. As the high tap water concentration of strontium was adequately reduced during the water purification process, contamination of the final dialysis fluid occurred by the addition of concentrates contaminated with strontium. Besides the dialysate, other factors, such as duration of dialysis, vitamin D supplements, or types of phosphate binders, played a less important role in the accumulation of the element.ConclusionsData of this multicenter study indicate patients of particular dialysis centers to be at an increased risk for strontium accumulation, the clinical consequence of which is under current investigation

Increased bone strontium levels in hemodialysis patients with osteomalacia

Increased bone strontium levels in hemodialysis patients with osteomalacia.BackgroundIn this study, we report on the association between increased bone strontium levels and the presence of osteomalacia in end-stage renal failure patients treated by hemodialysis.MethodsWe performed a histologic examination and determined the strontium content and strontium/calcium ratios in bone biopsies of 100 hemodialysis patients recruited from various centers all over the world. Aside from the bone strontium concentration, the bone aluminum content was assessed. The bone zinc concentration, a nonrelevant element for bone toxicity, was also measured.ResultsBone strontium levels and bone strontium/calcium ratios were increased in subjects with osteomalacia when compared with those with the other types of renal osteodystrophy. Bone strontium and bone calcium levels correlated with each other. The slope of the linear regression curve correlating these parameters was much steeper in the osteomalacic group (Y = 2.22X - 120) as compared with the other types of renal osteodystrophy (Y = 0.52X - 5.7). Within the group of patients with osteomalacia, bone strontium levels also significantly correlated with the bone aluminum content (r = 0.72, P = 0.018). No such correlation was found for the other types of renal osteodystrophy. The bone zinc concentration of subjects with normal renal function did not differ significantly from the values noted for the various types of renal osteodystrophy taken as separate groups, nor could increased bone zinc concentrations be associated with a particular bone lesion.ConclusionsOur data demonstrate an association between osteomalacia and increased bone strontium concentrations in dialysis patients. Further studies are warranted to establish whether strontium plays either a primary, secondary, or contributive role in the development of the latter type of renal osteodystrophy

Rheological behavior of β-Ti and NiTi powders produced by atomization for SLM production of open porous orthopedic implants

The growing interest for Selective Laser Melting (SLM) in orthopedic implant manufacturing is accompanied by the introduction of novel Ti alloys, in particular β-Ti for their excellent corrosion resistance as well as favorable combination of high mechanical strength, fatigue resistance and relatively low elastic modulus. As part of the SLM process for producing quality β-Ti parts powder flowability is essential to achieve uniform thickness of powder layers. In this work the flowability of different gas atomized β-Ti, including NiTi, powders has been studied. Their rheological properties were compared to those of commercially available plasma-atomized Ti–6Al–4V powder using a newly developed semi-automatic experimental set-up. Not only the particle size, shape and size distribution of the powders display a large influence on the powder flowability but also particle surface properties such as roughness, chemical composition and the presence of liquid on the surface of the particles. It was found that plasma or gas atomization production techniques for SLM powder have a considerable effect on the particle topography. Among the powders studied regarding SLM applicability only rheological properties of the fine size fraction (25–45 μm) of Ti–45Nb didn't conform to SLM processing requirements. To improve flowability of the Ti–45Nb powder itwas annealed both in air and argon atmosphere at 600 °C during 1 h, resulting in an improved rheological behavior suitable for SLM processing