Numerical and experimental results from measuring spinal implant stability

Nowadays, there are many diagnostic methods in medicine. A negative effect in implantology has been recognized since the 1980s. In general terms, if an implant is introduced into the body, it is sometimes not accepted by the organism. This effect is usually referred to as low level of implant stability. There are many reasons why such an effect takes place. This paper is focused on the mechanical point of view. There is a relation between mechanical movement of an implant and success of the surgery [1, 2]. Cervical implant was chosen for our research because there is no information about the stability thereof. Such knowledge can benefit surgeons. A device based on measuring response function was designed. This device is connected to an implant. The implant and its surrounding bone are the boundary conditions. It was expected that these boundary conditions can affect frequency response function in a connected structure. A beam with exactly defined mechanical properties was designed for cervical implant. A vibration head was attached to one end of the beam. The vibration head produces transversal vibration. An accelerometer to measure the response was attached to the other end. The vibration head utilizes a piezo actuator and inertia force. This device was tested in vitro on a cervical cadaver in a laboratory. Mechanical stability of the implant was simulated with axial force. The results were obtained in a frequency domain by Fourier transform. The focus is on resonance frequencies and resonance amplitudes. They show that there is a correlation between implant stability and response function evaluation. Further, a numerical model of the device designed was made. The model was built using the finite element method. Finally, the experimental and numerical models were compared

Effective Creation of Self-Referencing Citation Records

Acquiring citation records from online resources has become a popular approach to building bibliography for one's publication. LaTeX document preparation system is the most popular platform for typesetting publications in academia. It uses BibTeX as a tool used to describe and process lists of references. In this article we present a simple method that allows to automatically create a full self-referencing citation record for a collection of papers typeset and published within one proceedings of a conference. This greatly facilitates access to the bibliography entries for anyone who wishes to use them as part of their own publication.Získávání citačních záznamů elektronických zdrojů se stalo standardním požadavkem na vydavatele. V akademickém světě jsou standardními nástroji LaTeX pro sazbu a BibTeX pro práci s citacemi. V článku je prezentována jednoduchá metoda pro automatické vytvoření citační databáze v BibTeXu pro souborné dílo (sborník a.p.) sázené v LaTeXu. To usnadňuje další citovanost vytvořeného díla a článků v něm jejich autory

Synthesis of Purine - Amino Acid Conjugates

4. Conclusions A simple and efficient approach to the synthesis of (purin-6-yl)alanines based on Negishi cross-coupling reactions of 6-iodopurines and iodozinc- alanines applicable to the synthesis of both racemic and optically pure compounds was developed. Though analogous reactions were used before for the synthesis of some simple aryl- or hetarylaranines, this was the first successful use in the functionalization ofprotected nucleobases and nucleosides. A practical method for synthesis of enantiomerically pure (purin-6_ yl)phenylalanines by palladium catalyzeď, copper mediated Stille cross-coupling reactions ofprotected 4-(trimethylstanyl)phenylalanines and 6-iodopurines was developed. This method was used in the synthesis of series of (purin_6_ yl)phenylalanines (bases and nucleosides) varying in substitution in position 9 of purine scaffold and in absolute configuration on o-carbon ofphenylalanine. The shaughnessy method for the Suzuki cross-coupling reactions in aqueous media was further optimized and applied to the single-step synthesis of novel optically pure (adenin-8-yl)phenylalanines and (purine_6_yl)phenyl_ alanines. wide tolerance of this methodology towards variety of functionalities and its applicability to 1abile systems was demonstrated particularly by the very first examples of couplings...4. Conclusions A simple and efficient approach to the synthesis of (purin-6-yl)alanines based on Negishi cross-coupling reactions of 6-iodopurines and iodozinc- alanines applicable to the synthesis of both racemic and optically pure compounds was developed. Though analogous reactions were used before for the synthesis of some simple aryl- or hetarylaranines, this was the first successful use in the functionalization ofprotected nucleobases and nucleosides. A practical method for synthesis of enantiomerically pure (purin-6_ yl)phenylalanines by palladium catalyzeď, copper mediated Stille cross-coupling reactions ofprotected 4-(trimethylstanyl)phenylalanines and 6-iodopurines was developed. This method was used in the synthesis of series of (purin_6_ yl)phenylalanines (bases and nucleosides) varying in substitution in position 9 of purine scaffold and in absolute configuration on o-carbon ofphenylalanine. The shaughnessy method for the Suzuki cross-coupling reactions in aqueous media was further optimized and applied to the single-step synthesis of novel optically pure (adenin-8-yl)phenylalanines and (purine_6_yl)phenyl_ alanines. wide tolerance of this methodology towards variety of functionalities and its applicability to 1abile systems was demonstrated particularly by the very first examples of couplings...Katedra organické chemieDepartment of Organic ChemistryFaculty of SciencePřírodovědecká fakult

Correction: Čapek, P., et al. Sensing the Deadliest Toxin: Technologies for Botulinum Neurotoxin Detection. Toxins 2010, 2, 24-53

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Control of Traction Rail Vehicle with Freewheels

This paper is focused on the low-floor tramswith free-wheels driven by PMSM motors, especially ontheir traction control system. The first part describesmodern low-floor trams, particularly the type 15T producedby Škoda Transportation. The second part of the paperpresents the simulations of characteristics operating suchtram in the rail and the results of these simulations. Thelast part of the paper describes the mechanical constructionand electrical equipment of a light experimental rail car,that will be used as an experimental base for a improvementof the control system for the tram 15T

Application of non-destructive archeological methods at the Department of Archaeology in Plzen

Non-destructive archaeological approaches and methods have become an inseparable part of archaeological monument survey. They are also frequently used at the Department of Archaeology in Plzen. Here, over the past years, they have been applied in a number of cases. These include non-destructive documentation works on barrow burial and hill top sites, or the Middle Age and Modern settlements in forested areas Other significant activities have been carried out by means of geophysical surveys or aerial photography and remote sensing of Earth.Non-destructive archaeological approaches and methods have become an inseparable part of archaeological monument survey. They are also frequently used at the Department of Archaeology in Plzen. Here, over the past years, they have been applied in a number of cases. These include non-destructive documentation works on barrow burial and hill top sites, or the Middle Age and Modern settlements in forested areas Other significant activities have been carried out by means of geophysical surveys or aerial photography and remote sensing of Earth

Helium permeation through mixed matrix membranes based on polyimides and silicalite-1

Mixed matrix membranes based on modified polyimides and silicalite-1 were prepared and studied. The novel preparation approach consists in improvement of the interfacial adhesion by employment of the coupling agent 3-aminopropyltriethoxysilane in such a way which leads to forming of chemical bonds between polyimide and silicalite-1. Firstly polyimide chains were endcapped by this agent which subsequently enabled their reaction with groups naturally present on silicalite-1 surface. Membranes with silicalite-1 content up to 60 wt. % were prepared and characterized by SEM, light microscopy and permeation of gases, prevailingly of He. The accessibility of sililicalite-1 pores prior to embedding and after embedding into polymeric matrices was studied by an iodine indicator technique. The permeability of membranes for gases was measured using a semi-open permeation apparatus with a small volume. Helium permeability depended on filler content and increased monotonously with the increasing content of filler. There were, however, significant deviations of the permeability dependences on filler content from shapes predicted by Bruggeman’s model. The qualitative explanation of the data disagreement with the model was proposed based on a stratification of mixed matrix membranes found by SEM

Surface Integrity after Turning a Duplex Stainless Steel with Respect to Tool Geometry

This study deals with surface integrity expressed in terms of stress state as well as microstructure alterations after turning a duplex stainless steel. Residual stresses and the presence of strain-induced martensite are studied as functions of the rake angle. Residual stresses of surface and sub-surface layers were determined by the use of the X-ray diffraction and hole-drilling techniques. X-ray diffraction enables us to distinguish between residual stresses in each phase separately, which is not possible when the hole-drilling method is applied. Furthermore, alterations in the near surface region are also analysed by the use of the magnetic Barkhausen noise and metallographic observation