Újkőkori népességek csonttani leletei a Dél-Alföldről – A makroszkópos megfigyelések alkalmazási lehetőségei történeti népességek demográfiai és patológiai vizsgálata során

The osteological evidence of Neolithic populations from the Southern Great Plain of Hungary – An insight into the potential of macroscopic observations for the demographic and pathological analyses of past populations. This doctoral research provides a unique contribution to our knowledge of the Early Farmers of Europe in general and the Neolithic populations from the Southern Great Plain of Hungary in particular. The potential of macroscopic observations for the demographic and pathological analyses of past populations was demonstrated on this exceptional Neolithic sample, revealing despite the lack of contextual data, the damaged and fragmentary skeletal remains, and the restriction to morphological analyses, a mostly non-violent population prone to infections, with a physically stressful way of life and a diet leading to a high rate of dental disease and (at least occasionally) lack of vitamin C. In particular, the palaeopathological analysis uncovered the oldest cases of tuberculosis in Europe so far, as well as the probable oldest cases of scurvy. In addition, a potential case of leprosy and one of cancer were also discovered, which would be of great significance for the palaeopathological record if these can be confirmed by further studies

A model comparison to predict heat transfer during spot GTA welding

The present work deals with the estimation of the time evolution of the weld fusion boundary. This moving boundary is the result of a spot GTA welding process on a 316L stainless steel disk. The estimation is based on the iterative regularization method. Indeed, the three problems: direct, in variation and adjoint, classically associated with this method, are solved by the finite element method in a two-dimensional axisymmetric domain. The originality of this work is to treat an experimental estimation of a front motion using a model with a geometry including only the solid phase. In this model, the evolution of this solid domain during the fusion is set with the ALE moving mesh method (Arbitrary Lagrangian Eulerian). The numerical developments are realized with the commercial code Comsol Multiphysics® coupled with the software Matlab®. The estimation method has been validated in a previous work using theoretical data ([1]). The experimental data, used here for this identification are, temperatures measured by thermocouples in the solid phase, the temporal evolution of the melt pool boundary observed at the surface by a fast camera and the maximal dimensions of the melted zone measured on macrographs. These experimental data are also compared with numerical results obtained from a heat and fluid flow model taking into account surface tension effects, Lorentz forces and the deformation of the melt pool surface under arc pressure

Influence of a pulsed laser regime on surface finish induced by thedirect metal deposition process on a Ti64 alloy

tThe direct metal deposition (DMD) laser technique is a free-form metal deposition process, which allowsgenerating a prototype or small series of near net-shape structures. Despite numerous advantages, oneof the most critical issues of the technique is that produced pieces have a deleterious surface finish whichrequires post machining steps. Following recent investigations where the use of laser pulses instead of acontinuous regime was successful to obtain smoother DMD structures, this paper relates investigationson the influence of a pulsed laser regime on the surface finish induced by DMD on a widely used titaniumalloy (Ti64). Findings confirm that using high mean powers improves surface finish but also indicate aspecific effect of the laser operating mode: using a quasi-continuous pulsed mode instead of fully-cw laserheating is an efficient way for surface finish improvement. For similar average powers, the use of a pulsedmode with large duty cycles is clearly shown to provide smoothening effects. The formation of larger andstable melt pools having less pronounced lateral curvatures, and the reduction of thermal gradients andMarangoni flow in the external side of the fusion zone were assumed to be the main reasons for surfacefinish improvement. Additional results indicate that combining the benefits from a pulsed regime and auniform laser irradiation does not provide further reduction of surface roughness

Influence of various process conditions on surface finishes induced by the direct metal deposition laser technique on a Ti–6Al–4V alloy

The direct metal deposition (DMD) with laser is a free-form metal deposition process for manufacturing dense pieces, which allows generating a prototype or small series of near net-shape structures. One of the most critical issues is that produced pieces have a deleterious surface finish which systematically requires post machining steps. This problem has never been fully addressed before. The present work describes investigations on the DMD process, using an Yb-YAG disk laser, and a widely used titanium alloy (Ti–6Al–4V) to understand the influence of the main process parameters on the surface finish quality. The focus of our work was: (1) to understand the physical mechanisms responsible for deleterious surface finishes, (2) to propose different experimental solutions for improving surface finish. In order to understand the physical mechanisms responsible for deleterious surface finishes, we have carried out: (1) a precise characterization of the laser beam and the powder stream; (2) a large number of multi-layered walls using different process parameters (P(W), V(m/min), Dm (g/min), Gaussian or uniform beam distribution); (3) a real time fast camera analysis of melt pool dynamics and melt-pool – powder stream coupling; (4) a characterization of wall morphologies versus process parameters using 2D and 3D profilometry. The results confirm that surface degradation depends on two distinct aspects: the sticking of nonmelted or partially melted particles on the free surfaces, and the formation of menisci with more or less pronounced curvature radii. Among other aspects, a reduction of layer thickness and an increase of melt-pool volumes to favor re-melting processes are shown to have a beneficial effect on roughness parameters. Last, a simple analytical model was proposed to correlate melt-pool geometries to resulting surface finishes

7000 éves dél-magyarországi tuberkulózis esetek oszteológiai és molekuláris biológiai vizsgálata

This study derives from the macroscopic analysis of a Late Neolithic population from southern Hungary. Remains were recovered from a tell settlement at Hódmezővásárhely-Gorzsa from graves within the settlement as well as pits, ditches, houses and as stray finds. Pathological analysis of the 71 individuals revealed numerous cases of infections and non-specific stress indicators, metabolic diseases, and evidence of trauma and mechanical changes. Several cases showed potential signs of tuberculosis and further analyses were undertaken, including biomolecular studies. The five individuals were all very young adults and included a striking case of hypertrophic pulmonary osteopathy. The initial macroscopic diagnosis of these five cases was confirmed by lipid biomarker analyses, and three of them were corroborated by DNA analysis. At present, these 7000-year-old individuals are among the oldest palaeopathological and palaeomicrobiological cases of tuberculosis worldwide

Osteological and Biomolecular Evidence of a 7000-Year Old Case of Hypertrophic Pulmonary Osteopathy Secondary to Tuberculosis from Neolithic Hungary

Seventy-one individuals from the late Neolithic population of the 7000-year-old site of Hódmezővásárhely-Gorzsa were examined for their skeletal palaeopathology. This revealed numerous cases of infections and non-specific stress indicators in juveniles and adults, metabolic diseases in juveniles, and evidence of trauma and mechanical changes in adults. Several cases showed potential signs of tuberculosis, particularly the remains of the individual HGO-53. This is an important finding that has significant implications for our understanding of this community. The aim of the present study was to seek biomolecular evidence to confirm this diagnosis. HGO-53 was a young male with a striking case of hypertrophic pulmonary osteopathy (HPO), revealing rib changes and cavitations in the vertebral bodies. The initial macroscopic diagnosis of HPO secondary to tuberculosis was confirmed by analysis of Mycobacterium tuberculosis complex specific cell wall lipid biomarkers and corroborated by ancient DNA (aDNA) analysis. This case is the earliest known classical case of HPO on an adult human skeleton and is one of the oldest palaeopathological and palaeomicrobiological tuberculosis cases to date

Un dispositif d'essai d'expansion biaxiale à très hautes températures

L'emboutissage à chaud des aciers trempants type Usibor® 1500 est en un procédé en pleine expansiondans le monde de l'automobile. Ce procédé thermomécanique de mise en forme est basé sur l'austénitisation de l'acier revêtu et d'une trempe de cet acier sous les outils de mise en forme pour obtenir un état martensitique très résistant. Il nécessite de chauffer les flans à des températures entre 880 et 950°C ce qui est pour l'instant réalisé dans des fours avec des temps de chauffe de l'ordre de plusieurs minutes. Le projet ANR-PRICECAT a pour objectif de développer un nouveau procédé de chauffe des flans de forme en utilisant le principe de l'effet Joule, permettant d'obtenir des temps de chauffe beaucoup plus rapides, inférieurs à la minute. Jusqu'à présent, cette méthode de chauffe est utilisée dans des cas de flans de forme rectangulaires avec passage du courant entre deux électrodes aux extrémités. Mais chauffer uniformément un flan de forme quelconque à l'aide de cette méthode est beaucoup plus compliqué et n'est pas encore maîtrisé à l'heure actuelle. Dans un nouveau dispositif d'expansion biaxiale à haute température, une méthode de chauffe a été développée pour obtenir un champ de température homogène sur la partie centrale d'un flan circulaire. Cette méthode consiste à faire la rotation du champ électrique à travers trois paires d'électrodes situées sur la périphérie du flan. La tôle circulaire est serrée entre une matrice et un serre-flan isolés électriquement et un jonc en céramique qui assure l'étanchéité du montage. Une pression d'un gaz (ici de l'argon) est appliquée sur la zone chauffée permettant la réalisation de l'essai d'expansion, tout en contrôlant la température du flan par le passage du courant électrique appliqué. L'optimisation du champ électrique afin d'obtenir un chauffage rapide et homogène du flan circulaire a été obtenue par un modèle thermoélectrique réalisé sous COMSOL Multiphysics®. L'objectif de cette étude est de présenter les premiers résultats d'expansion équibiaxiale à hautes températures d'un acier Usibor®1500 à l'aide de ce dispositif. Peu d'essais existent pour ce type de chargement en température dans la littérature et ces résultats s'avèrent très importants pour connaître la limite de formabilité de cet acier dans un état de déformation biaxiale en fonction de la température

Modélisation du chauffage de flan circulaire dans un dispositif d'expansion biaxiale à haute température

Ce travail porte sur l'intégration d'un moyen de chauffage par conduction électrique (effet Joule) de flan circulaire au sein d'un dispositif d'expansion biaxiale. Ce dispositif permettra la caractérisation thermomécanique de l'Usibor®1500dans un trajet de déformation équibiaxiale à très haute température (jusqu'à 1°C). Dans un premier temps, on s'intéresse au chauffage de flan rectangulaire avec une confrontation entre expérience et simulation, qui a permis de valider le modèle thermoélectrique réalisé sous COMSOL Multiphysics®. Dans un second temps, on aborde l'optimisation du champ électrique afin d'obtenir un chauffage rapide et homogène d'un flan circulaire.This work focuses on the integration of an electrical conduction heating of circular blank in a bulge-test device. This device will allow the thermomechanical characterization of Usibor®1500under biaxial deformation at very high temperature (to 1°C). First a thermoelectric model using COMSOL Multiphysics® was developed to study the heating of a rectangular blank. This model is validated by comparing the calculated temperatures with thermocouple measurements. Secondly electrical field optimization is approached to obtain a fast and uniform heating of a circular blank

7000 éves dél-magyarországi tuberkulózis esetek oszteológiai és molekuláris biológiai vizsgálata

This study derives from the macroscopic analysis of a Late Neolithic population from southern Hungary. Remains were recovered from a tell settlement at Hódmezővásárhely-Gorzsa from graves within the settlement as well as pits, ditches, houses and as stray finds. Pathological analysis of the 71 individuals revealed numerous cases of infections and non-specific stress indicators, metabolic diseases, and evidence of trauma and mechanical changes. Several cases showed potential signs of tuberculosis and further analyses were undertaken, including biomolecular studies. The five individuals were all very young adults and included a striking case of hypertrophic pulmonary osteopathy. The initial macroscopic diagnosis of these five cases was confirmed by lipid biomarker analyses, and three of them were corroborated by DNA analysis. At present, these 7000-year-old individuals are among the oldest palaeopathological and palaeomicrobiological cases of tuberculosis worldwide

Cyclodipeptide synthases, a family of class-I aminoacyl-tRNA synthetase-like enzymes involved in non-ribosomal peptide synthesis

Cyclodipeptide synthases (CDPSs) belong to a newly defined family of enzymes that use aminoacyl-tRNAs (aa-tRNAs) as substrates to synthesize the two peptide bonds of various cyclodipeptides, which are the precursors of many natural products with noteworthy biological activities. Here, we describe the crystal structure of AlbC, a CDPS from Streptomyces noursei. The AlbC structure consists of a monomer containing a Rossmann-fold domain. Strikingly, it is highly similar to the catalytic domain of class-I aminoacyl-tRNA synthetases (aaRSs), especially class-Ic TyrRSs and TrpRSs. AlbC contains a deep pocket, highly conserved among CDPSs. Site-directed mutagenesis studies indicate that this pocket accommodates the aminoacyl moiety of the aa-tRNA substrate in a way similar to that used by TyrRSs to recognize their tyrosine substrates. These studies also suggest that the tRNA moiety of the aa-tRNA interacts with AlbC via at least one patch of basic residues, which is conserved among CDPSs but not present in class-Ic aaRSs. AlbC catalyses its two-substrate reaction via a ping-pong mechanism with a covalent intermediate in which l-Phe is shown to be transferred from Phe-tRNAPhe to an active serine. These findings provide insight into the molecular bases of the interactions between CDPSs and their aa-tRNAs substrates, and the catalytic mechanism used by CDPSs to achieve the non-ribosomal synthesis of cyclodipeptides