Translational motions in human knee joint model

Different authors are dealing with description of motion components of human knee joint. The relative motion between femur and tibia realized by knee joint is ensured by complicated condyle surfaces and ligaments. Main part of authors focus merely on rotational displacement of human knee joint such as flexion-extension, abduction-adduction, tibial rotation. In order to achieve implanted prostheses we have to recognize not only the rotational but also translational kinematical parameters of human knee joint. Authors of this paper for description of motion of knee joint joined coordinate-systems on the basis of anatomical landmarks to the femur and tibia moreover joined a threecylindrical mechanism as mechanical model to the axes of coordinate-systems. In 2nd phase authors determined the six independent kinematical parameters of tibia compared to the fixed femur during flexion and extension. The experimental examinations were carried out on cadaver knees. The positioning was tracked by optical positioning appliance

Geochemical classification of oxidized Mn-ores from Úrkút (W Hungary) and its consequences for ore genesis

Abstract Analytical data of primary oxidized manganese ores were processed by statistical methods. Six hundred and twenty-one samples were measured (Mn, Fe, Si, and P); thus 2,426 assay data were available. The statistical pointer numbers, the distribution of the elements and the results of the correlational analysis showed the heterogeneity of the ore samples where the measured elements correlated weakly. The samples were grouped by the 4 elements to decrease the heterogeneity and the concentration of elements, and these relationships in the groups were examined. Very few and weak relationships were proved in the groups by the results of the correlational and regressional analysis. It is possible that not the heterogeneity of the samples but one or more syngenetic or postgenetic processes caused the absence of relationships. The multivariate statistical processes (principal component analysis, discriminance analysis) allow the determination of the background factors, namely which are the effects that produced the ore. Consequently — with high probability — the ore was formed by two processes. The most likely are hydrothermal and microbial ones (on the basis of geochemical results), but supergene enrichment processes can also be taken into consideration. Both hydrothermal and microbial processes played a significant role in the majority of the samples (81%), which are the ferruginous manganese ores. In the smaller group of samples (19%) the hydrothermal process predominates but the microbial one is also influential, namely for the low iron-bearing manganese ores of excellent quality

Introduction of computer aided method in education of mechanics at the Faculty of Engineering in University of Szeged

The spread of mass education in Hungary needs new methods in teaching of technical basic subjects. It is necessary because the quality of the education should be maintained in spite of the increase in the number of students. Department of Mechanics and Technical Drawing (Mechanical Engineering Faculty of Szent István University, Hungary) have developed and applied computer aided method for give out and correction mechanics homework in the full-time and distance education for the last fifteen years. Other Hungarian universities and colleges apply this method. The circle of such applied task types in the program package has been increasing continuously according to demand. First author applied a similar program package previously in Szolnok College. On the basis of experience of mechanics teachers using this method it is recommended to introduce it at the Faculty of Engineering in University of Szeged. In the frame of this paper the authors present the method and the program, moreover they summarize their gained experiences connccted to the applying of the program

Multiphysical computations of the electrical machines using FEM

In this paper three problems representing the multiphysical aspect of electrical machine computation are addressed. The interaction between magnetic and structural mechanical systems is demonstrated by the finite element method (FEM) structural investigation of the turbo-generator end-winding deformations. Multiphysical simulation of the acoustical problem is presented by weakly coupled electromagnetic, structural dynamic and acoustic simulations. And finally, a procedure based on computational fluid dynamics (CFD) simulation for acquiring the convective heat transfer coefficients is proposed in order to improve the accuracy of the coupled electro-thermal FEM simulations

Vasoactive intestinal peptide, whose receptor-mediated signalling may be defective in alopecia areata, provides protection from hair follicle immune privilege collapse

Background: Alopecia areata (AA) is an autoimmune disorder whose pathogenesis involves the collapse of the relative immune privilege (IP) of the hair follicle (HF). Given that vasoactive intestinal peptide (VIP) is an immunoinhibitory neuropeptide released by perifollicular sensory nerve fibres, which play a role in IP maintenance, it may modulate human HF-IP and thus be therapeutically relevant for AA. Objectives: To answer the following questions: Do human HFs express VIP receptors, and does their stimulation protect from or restore experimentally induced HF-IP collapse? Is VIP signalling defective in AA HFs?. Methods: Firstly, VIP and VIP receptor (VPAC1, VPAC2) expression in human scalp HFs and AA skin was assessed. In HF organ culture, we then explored whether VIP treatment can restore and/or protect from interferon-γ-induced HF-IP collapse, assessing the expression of the key IP markers by quantitative (immuno-)histomorphometry. Results: Here we provide the first evidence that VIP receptors are expressed in the epithelium of healthy human HFs at the gene and protein level. Furthermore, VIP receptor protein expression, but not VIP+ nerve fibres, is significantly downregulated in lesional hair bulbs of patients with AA, suggesting defects in VIP receptor-mediated signalling. Moreover, we show that VIP protects the HF from experimentally induced IP collapse in vitro, but does not fully restore it once collapsed. Conclusions: These pilot data suggest that insufficient VIP receptor-mediated signalling may contribute to impairing HF-IP in patients with AA, and that VIP is a promising candidate ‘HF-IP guardian’ that may be therapeutically exploited to inhibit the progression of AA lesions.</p

The cultural and geopolitical dimensions of nation-building in the Ukraine

Ukraine belongs among those young countries where the beginnings of democratisation and nation-building approximately coincided. While the development of nation states in Central Europe was usually preceded by the development of nations, the biggest dilemma in the Ukraine is whether a nation-state programme — parallel to the aim of state-building — is able to bring unfinished nation-building to completion. Ukraine sways between the EU and Russia with enormous amplitude. The alternating orientation between the West and the East can be ascribed to superpower ambitions reaching beyond Ukraine. Eventually, internal and external determinants are intertwined and mutually interact with one another. The aim of the paper is to explain the dilemmas arising from identity problems behind the Ukraine’s internal and external orientation