REVERSE ENGINEERING OF THE MITKOVIC TYPE INTERNAL FIXATOR FOR LATERAL TIBIAL PLATEAU

In orthopaedic surgery it is very important to use proper fixation techniques in the treatment of various medical conditions, i.e. bone fractures or other traumas. If an internal fixation method, such as plating, is required, it is possible to use Dynamic Compression Plates (DCP) or Locking Compression Plates (LCP) and their variants. For DCP implants it is important to match the patient's bone shape with the most possible accuracy, so that the most frequent implant bending is applied in the surgery. For LCP implants it is not so important to match the patient’s bone shape, but additional locking screw holes are required. To improve the geometrical accuracy and anatomical correctness of the shape of DCP and to improve the LCP geometric definition, new geometrical modelling methods for the Mitkovic type internal fixator for Lateral Tibia Plateau are developed and presented in this research. The presented results are quite promising; it can be concluded that these methods can be applied to the creation of geometrical models of internal fixator customized for the given patient or optimized for a group of patients with required geometrical accuracy and morphological correctness

Variability in Chemical Composition and Abundance of the Rare Tertiary Relict Pinus heldreichii in Serbia

The particular significance of the whitebark pine (Pinus heldreichii Christ.) stems from the fact that it is a tertiary relict and Balkanic subendemite covering a very narrow and intermittent area in Serbia. A representative pool of 48 adult trees originating from three populations, one recently discovered natural (Population I) and two planted populations (Populations II and III) was investigated in order to evaluate the intra-and interpopulation variability of the essential oil of the complete fund of P. heldreichii in Serbia. In the pine-needle-terpene profile, 104 compounds were detected, 84 of which could be identified. Among the essential-oil constituents, monoterpenes and sesquiterpenes dominated, comprising ca. 90% of the essential oil. The terpenic profile of Population I was characterized by a predominance of monoterpenes (e. g., limonene (1), alpha-pinene, and Delta(3)-carene (4)), while sesquiterpenes (e. g., germacrene D (2) and beta-caryophyllene (3)) obviously preponderated in the profile of Populations II and III. This study also demonstrated that the abundance of whitebark pines in Serbia had significantly changed over the last few decades. The number of individuals in the natural population had increased, while the number of individuals in the planted populations had decreased. Today, the whitebark pine fund in Serbia comprises less than 250 trees.nul

Needle morpho-anatomy and pollen morpho-physiology of selected conifers in urbanconditions

Comparison of twelve conifer species (Abies alba, A. concolor, A. nordmanniana, A. pinsapo, Cedrus atlantica, C. deodara, Picea abies, P. omorika, P. pungens, Pseudotsuga menziesii, Taxus baccata, andPinus nigra) in the sense of needle morpho-anatomy and pollen morpho-physiology, in correlation to air pollution, was performed for the first time. Analyzed properties of species werealso compared with literature sources. Listed conifers were investigated in five Belgrade parks, characterised by different degrees of air pollution, especially CO2. Their rank, I-V, was performed from non-polluted to heavily-polluted parks. Ranking in the sense of needle morpho-anatomy and pollen morpho-physiology didnot match expected ones, but park V remained the worst for many analyzed species. Trees with shorter needles had greater stomatal density, which was particularly prominent in A. alba, A. nordmanniana, P. abies, P. omorika, P. nigraand T. baccata. The pollen grains of C. atlanticaand T. baccatawere the most sensitive to air pollution. In some analyzed species distance of particular trees close to the heavy traffic also was in correlation with needle dimensions (P. omorika, A. concolor, A. nordmanniana, P. nigra), stomatal density (A. alba, P. abies, P. omorika, P. pungens) and pollen vitality (A. pinsapo, C. atlantica, P. menziessi, P. nigra, andT. baccata)

Alpine thermal events in the central Serbo‑Macedonian Massif (southeastern Serbia)

The Serbo-Macedonian Massif (SMM) represents a crystalline belt situated between the two diverging branches of the Eastern Mediterranean Alpine orogenic system, the northeast-vergent Carpatho-Balkanides and the southwest-vergent Dinarides and the Hellenides. We have applied fission-track analysis on apatites and zircons, coupled with structural field observations in order to reveal the low-temperature evolution of the SMM. Additionally, the age and geochemistry of the Palaeogene igneous rocks (i.e. Surdulica granodiorite and dacitic volcanic rocks) were determined by the LA-ICPMS U–Pb geochronology of zircons and geochemical analysis of main and trace elements in whole-rock samples. Three major cooling stages have been distinguished from the late Early Cretaceous to the Oligocene. The first stage represents rapid cooling through the partial annealing zones of zircon and apatite (300–60 °C) during the late Early to early Late Cretaceous (ca. 110–ca. 90 Ma). It is related to a post-orogenic extension following the regional nappe-stacking event in the Early Cretaceous. Middle to late Eocene (ca. 48–ca. 39 Ma) cooling is related to the formation of the Crnook–Osogovo–Lisets extensional dome and its exhumation along low-angle normal faults. The third event is related to regional cooling following the late Eocene magmatic pulse. During this pulse, the areas surrounding the Surdulica granodiorite (36 ± 1 Ma) and the slightly younger volcanic bodies (ca. 35 Ma) have reached temperatures higher than the apatite closure temperature (120 °C) but lower than ca. 250 °C. The geochemistry of the igneous samples reveals late- to post-orogenic tectonic setting during magma generation