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Rodent models are commonly used in pre-clinical research of magnesium (Mg) -based and other types of biomaterials for fracture treatment. Most studies selected unstable fixation methods, and there is a lack of multimodal longitudinal in vivo monitoring of bone healing. The purpose of this study is to develop a rat femoral fracture model stabilized by external fixation with intra-medullary Mg implant, and to investigate the dynamic bone union process with several imaging techniques offering complementing insights into the process. Pure Mg pins were prepared, followed by in vitro degradation test. Male Sprague-Dawley rats in the experimental group underwent femoral osteotomy stabilized by external fixators with intra-medullary implantation of Mg pins, and the control group underwent external fixation without intra-medullary implants. Post-operative radiograph, micro-CT and B-mode ultrasonography were acquired directly after surgery, and re-examined at week 4, 8 and 12. Bone tissue volume, in vivo implant degradation, histological staining and MRI images were analyzed using ex vivo samples. Both groups achieved fracture union at week 12, and the dynamic healing process was illustrated by in vivo radiograph, micro-CT and ultrasonography. Bilateral whole femur ex vivo analysis further demonstrated increased ratio of bone tissue volume in the surgical femur with Mg implants, and in vivo degradation of Mg pins was slower than in vitro results. Titanium screws rather than intra-medullary Mg pins were the source of artifact in MRI. This pilot study showed the rat fracture model with external fixation and intra-medullary Mg implantation, to be an effective method for dynamic in vivo monitoring of the bone healing process. Future application of the animal model may facilitate pre-clinical translational research of biodegradable orthopaedic implant materials for fracture treatment.

Impurities, particularly oxygen, are a critical issue to address in metal-injection-molding (MIM) processed Ti-Nb-Zr biomaterials. The addition of rare earth (RE) elements such as yttrium is a possible solution to the impurity problem due to their potential for scavenging oxygen. The impacts of added Y on the sinterability, microstructure and mechanical properties of the MIMed Ti-Nb-Zr, however, largely remain unclear. In this study, different sized Y particles with varying weight fractions have been added to the β Ti-Nb-Zr alloy in order to elucidate the aforementioned aspects. It has been found that, although the added Y has an obvious β grain refinement effect, its impacts on the residual porosity, ultimate tensile strength and tensile toughness can be significantly negative, particularly if using large sized Y particles. Small sized (

The study is focussing towards Metal Injection Moulding (MIM) of Mg-alloys for biomedical implant applications. Especially the influence of the sintering processing necessary for the consolidation of the finished part is in focus of this study. In doing so, the chosen high strength EZK400 Mg-alloy powder material was sintered using different sintering support bottom plate materials to evaluate the possibility of iron impurity pick up during sintering. It can be shown that iron pick up took place from the steel bottom plate into the specimen. Despite the fact that a separating boron nitrite (BN) barrier layer was used and the Mg-Fe phase diagram is not predicting any significant solubility to each other. As a result of this study a new bottom plate material not harming the sintering and the biodegradation performance of the as sintered material, namely a carbon plate material, was found.

The history of the introduction of Heracleum sosnowskyi in the territory of Siberia is briefly reviewed. Based on the available literature data and other sources of information, it was established that this species was introduced from 1950s until 1980s in the Southern Trans-Urals (Kurgan and Tyumen regions), southeast of Western Siberia (Novosibirsk and Tomsk regions) and in the Northern Altai. The expansion of this species in the territory of Siberia probably began in the early 2000s. In the last 10–15 years, this species dispersed in parts of Western Siberia. At present, several centers of spreading of H. sosnowskyi on Western Siberia are known (mainly related to places of the former culture). In Siberia, the problem of the invasion of H. sosnowskyi is the most serious in the Altai Republic, where this species not only settles in disturbed habitats, but also penetrates into natural plant communities, which poses a threat to the unique biodiversity of the region. Исследования выполнены при финансовой поддержке гранта РФФИ 16-04-01246 А «Выявление закономерностей и современных тенденций синантропизации флоры Южной Сибири».

One strategy to make PM titanium components competitive in terms of mechanical properties is the addition of suitable alloying elements. PM offers the possibility to adapt the alloy composition in order to achieve the required properties. In this study, different alloying elements were introduced into α/β titanium alloys and fatigue behaviour was evaluated. Four-point bending fatigue tests with a stress ratio of 0.2 were performed on specimens manufactured by metal injection moulding (MIM) and shot peening. Results showed an enhanced sintering activity of Ti-6Al-7Nb by adding small amounts of iron. The impact on fatigue properties was evaluated. The increase of oxygen in Ti-6Al-7Nb from 0.15 wt.% to 0.45 wt.% caused a decrease in elongation from 16% to 6%. However the fatigue strength at 107 cycles is just slightly reduced from 450 to 350 MPa. The addition of 0.5 wt.% yttrium powder to gas atomized Ti‑6Al‑4V powder led to a noticeable refinement of the microstructure of the sintered parts, due to the formation of Y2O3 particles, which hinder grain growth. In spite of a slightly higher residual porosity, the microstructural refinement increased the fatigue strength at 107 cycles from 450 to 470 MPa. At 106 cycles, the fatigue strength increased even from 705 to 765 MPa. The addition of yttrium did not result in a higher oxygen pick up, which indicates a scavenging of oxygen from the titanium matrix by formation of Y2O3 during sintering. Contrary to the fatigue strength results, the scavenging effect led to a decrease in tensile strength of about 70 MPa. The microstructure of fatigue-tested specimens was characterized by using optical and scanning electron microscopy.

Biodegradability and mechanical properties similar to natural bone have made Mg alloys potential competitors for metal implant applications. Mg-Ca alloys are of interest as Ca is an essential element in the human body. However, an increased Mg2Ca secondary phase with increasing Ca addition results in pitting corrosion in these alloys. Reports suggest that Mg alloys with ≤ 1wt % Ca additions possess good degradation resistance. Hence, Mg-xCa alloys (x= 0.3, 0.6, 0.9 wt %) were fabricated by gravity die chill casting and powder metallurgy (PM) techniques. Their ‘mean degradation depth, h (µm)’ values were measured by immersion test. Physiological cell-culture medium DMEM+ Glutamax with proteins (10% FBS) and an incubator were adopted for conducting the test. The volume fraction of Mg2Ca was calculated with Image J image analysis software. Results show that degradation behavior is influenced by the amount of secondary phase and its distribution in the Mg matrix. PM alloys showed homogenous degradation compared to the as cast alloys. The highest degradation resistance was exhibited by PM processed Mg-0.3Ca alloy with lowest h value of 0.39 µm. A long term immersion test revealed the ‘mean degradation rate, ḣ∞ (µm/day)’ as 0.51 µm/day., Journal of Medical Materials and Technologies, Vol. 1 No. 2 (2017): Proceedings of Euro BioMAT

In powder metallurgical processing the sintering process, as well as heat treatments, can drastically influence microstructure formation. In the case of γ-titanium aluminides, it is critical to achieve certain microstructure parameters, such as colony size, porosity and grain boundary morphology in order to obtain appropriate mechanical properties. In this study, the effect of a heat treatment implemented after sintering with the objective of varying the colony size was investigated. Specimens of Ti-45Al-5Nb-0.2B-0.2C prepared by metal injection moulding and uniaxial pressing of feedstock were used to evaluate the tensile and creep properties. Heat treatments conducted at 1350 and 1400 °C for 3 h led to colony sizes of approximately 100 and 200 μm, respectively. Classically, there is an inverse relationship between grain size and creep resistance, nonetheless, for γ-titanium aluminides, the morphology of the colony boundaries was also found to play a role. The larger colony sizes achieved with the heat treatments did not improve the primary creep resistance, which was explained by the change in the morphology of the colony boundaries as they became larger.

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Research on biomaterials is connected inherently with the various aspects of materials science, chemistry, biology and medicine. Frequently used biomaterials for implants are titanium alloys because of their high corrosion resistance and biocompatible behaviour together with high strength and low density. One main characteristic property for the consideration of a potential implant material is the Young’s modulus which should correspond to that of human bone (4~30 GPa) as close as possible. β-Ti alloys exhibit currently the lowest value of typically 60 to 80GPa. β-Ti phase is stabilized with additive elements such as Mo, Ta, Hf and Nb. In particular, Ti-Nb alloys can exhibit a Young’s modulus around 50 to 60 GPa. Metal Injection Moulding (MIM) is a promising production technology because it overcomes the productivity and shape limitations of traditional powder compaction methods. However, formation of carbide precipitates at the grain boundaries deteriorating the ductile behavior of the materialhas become a challenge in MIM. Recent research using MIM on Ti-22Nb with the addition of Zr has revealed the reduction of carbide precipitates. In this study, different amounts of zirconium were added varying between 2 to 10 wt%. Samples produced with 10% Zr revealed the highest tensile strength of 840 MPa. In addition, specimens with higher zirconium content showed the highest ductility. XRD measurements revealed an increase in lattice constant effecting an increase of the carbon solubility of the Ti-matrix and, thus, a reduction of the carbide precipitation.

Fragestellung: In der vorliegenden Studie werden die Charakteristika von bei transperinealer Prostatastanzbiopsie ausschließlich anterior festgestellten Prostatakarzinomen (APC) beschrieben. Methoden: 300 Patienten mit vermutetem Prostatakarzinom (PCA) (medianes Alter 65 Jahre, medianes PSA [for full text, please go to the a.m. URL], 61. Kongress der Nordrhein-Westfälischen Gesellschaft für Urologie

In jüngster Zeit findet Mg zunehmendes Interesse als bioabbaubares Implantatmaterial für zukünftige biomedizinische Anwendungen [1, 2]. Zur Konditionierung von Festigkeit, Steifigkeit und Degradationsverhalten werden derzeit Legierungselemente (LE) wie z.B. Gd/Dy/Zn/Ag oder Ca untersucht. Neben dem Einfluss dieser LE auf das Bioabbauverhalten darf jedoch der Einfluss von bereits im Ausgangsmaterial vorhandenen Verunreinigungen wie Fe, Ni oder Cu nicht außer Acht gelassen werden. Dieser spielt bei der Eignungsfeststellung der gewählten Mg-Legierung als Biomaterial möglicherweise eine Schlüsselrolle und kann die eigentliche Wirkung des gewählten LE überdecken. Dies wiederum kann zur Fehlinterpretation von Ergebnissen und zur falschen Schlussfindung bei der Legierungswahl führen. Um dies zu verhindern ist ein vollständiger Wissensschatz über die vorhandenen Verunreinigungen und dessen Einfluss auf das Bioabbauverhalten notwendig. Diese Arbeit gibt einen Überblick wie Verunreinigungen an homogenem pulvermetallurgischen (PM) Ausgangsmaterialien bestimmt werden können und wie sie die Bioabbaubarkeit beeinflussen.

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Permanent implants have to fulfill a great variety of requirements related to both material and geometry. In addition, manufacturing costs play a role, which is getting steadily more and more important. Metal Injection Molding (MIM) of titanium alloy powders may contribute to the development of implants with higher functionality without increasing the price. High degree of freedom with regard to geometry, high material efficiency, and the possibility to create even porous structures are main benefits from applying this technique. Today, even long-term implants made from Ti–6Al–4V by MIM are commercially available. However, in order to improve fatigue behavior it is beneficial to perform a minor variation of Ti–6Al–4V by adding a low amount of boron. In this paper the mechanical, biological, and corrosion properties of specimens manufactured from Ti–6Al–4V–0.5B alloy by MIM are presented. In order to exclude unknown reactions in the body environment due to the boron content, corrosion, and biological tests are performed. Tensile and fatigue tests characterize the mechanical properties. Potentiodynamic polarization and electrochemical impedance spectroscopy are done in comparison to wrought and to MIM processed Ti–6Al–4V material. For cell experiments cancellous bone cells are cultured to perform adhesion, proliferation, and viability experiments. The results presented here show that the alloy Ti–6Al–4V–0.5B satisfies all basic needs of a material for highly loaded permanent implants manufactured by MIM.

Fatigue and tensile mechanical properties of Ti-6Al-4 V alloy processed by metal injection moulding (MIM) technology were evaluated in this investigation. Two critical parameters, binder content of the feedstock and maximum sintering temperature, were studied. Samples sintered at 1350 °C exhibited higher tensile strength than those sintered at 1250 °C. Higher content of binder promoted an increase of the surface quality of MIM components. Consequently, the fatigue endurance limit increased from not, vert, similar350 MPa (components with lower binder content) to not, vert, similar400 MPa (samples with a higher binder content). Furthermore, reduction of ductility was observed for changing from closed to open porosity; however, the fatigue resistance did not follow the same trend. This is probably due to the fact that better surface quality and smaller grain size compensated the negative influence of porosity on the fatigue behaviour.

Pollen data from a Levinson-Lessing Lake sediment core (74°28'N, 98°38'E) and Cape Sabler,Taymyr Lake permafrost sequences (74°33'N, 100°32'E) reveal substantial environmental changeson the northern Taymyr Peninsula during the last c. 32 000 14C years. The continuous recordsconfirm that a scarce steppe-like vegetation with Poaceae, Artemisia, and Cyperaceae dominatedc. 32 000-10 300 14C yr BP, while tundra-like vegetation with Oxyria, Ranunculaceae andCaryophyllaceae grew in wetter areas. The coldest interval occurred c. 18 000 yr BP. Lateglacialpollen data show several warming events followed by a climate deterioration c. 10 500 14C yr BP,which may correspond with the Younger Dryas. The Late Pleistocene/Holocene transition,c. 10 300-10 000 14C yr BP, is characterized by a change from the herb-dominated vegetation toshrubby tundra with Betula sect. Nanae and Salix. Alnus fruticosa arrived locally c. 9000-8500 14Cyr BP and disappeared c. 4000-3500 14C yr BP. Communities of Betula sect. Nanae, broadlydistributed at c. 10,000-3500 14C yr BP, almost disappeared when vegetation became similar tothe modern herb tundra after 3500-3000 14C yr BP. Quantitative climate reconstructions showLast Glacial Maximum summer temperature about 4°C below present and Preboreal (c. 10 00014C yr BP) temperature 2-4°C above present. Maximum summer temperature occurred between10 000 and 5500 14C yr BP; later summers were similar to present or slightly warmer.

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Euro PM2017 Congress & Exhibition, Milan, HZG, Italy, 1 Oct 2017 - 5 Oct 2017, In this study fatigue and tensile test specimens were produced by Metal Injection Moulding (MIM) using gas atomised Ti-6Al-4V-powder with addition of 0.5 wt.% yttrium powder as well as pure Ti 6Al 4V powder as reference. The addition of yttrium resulted in a noticeably refinement of the grain size from 150 µm to 50 µm by formation of Y2O3 particles hindering grain growth. Corresponding scavenging of oxygen from the titanium matrix led to a decrease in tensile strength of about 70 MPa. Surprisingly, fatigue strength was enhanced by 15 to 60 MPa, probably caused by the colony refinement overcompensating the effect of decreased yield strength. To understand the formation kinetics of Y2O3, in situ X-ray diffraction experiments were performed during sintering using synchrotron radiation. The results show that only a small amount of yttrium was dissolved while the remainder was oxidized. The formation of Y2O3 took place between 850 and 1050 °C.

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