Influence of purge, time of waiting and TiCl4 dosing time in a low-pressure atomic layer deposition (ALD) reactor on properties of TiO2 layer

The aim of the study was to evaluate the influence of the ALD process parameters on mechanical properties and corrosion resistance of TiO2 layer. The TiO2 layer was deposited on stainless steel surfaces at constant temperature T = 200 °C and number of cycles nc = 500 (g ≈ 25 nm). The applied methodology consisted of potentiodynamic and impedance studies, as well as adhesion test. The obtained results were the basis for selection of surface treatment method for stainless steel implants for contact with blood. Appropriate parameters of surface treatment realized by means of the ALD method is of significant importance. It will contribute to the development of technological conditions of specified deposition parameters of TiO2 layers on steel implants

Influence of purge, time of waiting and TiCl4 dosing time in a low-pressure atomic layer deposition (ALD) reactor on properties of TiO2 layer

The aim of the study was to evaluate the influence of the ALD process parameters on mechanical properties and corrosion resistance of TiO2 layer. The TiO2 layer was deposited on stainless steel surfaces at constant temperature T = 200 °C and number of cycles nc = 500 (g ≈ 25 nm). The applied methodology consisted of potentiodynamic and impedance studies, as well as adhesion test. The obtained results were the basis for selection of surface treatment method for stainless steel implants for contact with blood. Appropriate parameters of surface treatment realized by means of the ALD method is of significant importance. It will contribute to the development of technological conditions of specified deposition parameters of TiO2 layers on steel implants

Physiochemical properties of TiO2 nanoparticle thin films deposited on stainless steel

The purpose of this study was to evaluate the usefulness of TiO2 layer to improve hemocompatibility of 316LVM stainless steel. The TiO2 layers studied in this work were deposited from TiCl4 and H2O in a low-pressure Atomic Layer Deposition (ALD) reactor taking into account number of cycles and process temperature. As a part of the research electrochemical studies of the layer after 28 days exposure to artificial plasma were carried out. In particular, potentiostatic, potentiodynamic and impedance studies were conducted. The obtained results were the basis for selection of surface treatment method dedicated to blood-contacting stainless steel implants

On the electropolishing and anodic oxidation of Ti-15Mo alloy

This paper presents research on modifying the surface of Ti-15Mo alloy using electropolishing and anodic passivation. The electropolishing process was carried out in solutions containing sulfuric acid, ethylene glycol, ammonium fluoride and oxalic acid. Whereas a voltage range from 20 to 100 V and a 1 M orthophosphoric acid solution were used during the anodic passivation. The influence of above mentioned processes parameters on the quality of the obtained oxide layer on Ti-15Mo alloy was investigated. The analysis of Ti-15Mo surface after modification was performed using scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), ellipsometry, and mechanical tests. Moreover, the corrosion resistance was investigated using a potentiostatic method in Ringer's solution. It was found that electropolishing leads to an increase in the surface homogeneity and to the form of an oxide layer, which consisted of TiO2 and MoO3. Whereas the oxide layers obtained during anodic passivation were characterized by different properties depending on the applied voltage. The anodic passivation at various voltages (20-100 V) increased the surface wettability (94.5°-87.6°) in comparison to the electropolished sample (97.5°). Moreover, the obtained oxide layer after anodization exhibited a high hardness. The electrolytic polishing and anodic passivation of Ti-15Mo also improved corrosion resistance of the alloy in contact with Ringer's solution. The sample anodized at 80 V presented the highest corrosion resistance by the smallest corrosion current density (1.4 nA cm-2) and the highest polarization resistance (37.4 MΩ cm2). © 2016 Elsevier Ltd. All rights reserved

The influence of anisotropy in numerical modelling of orthogonal cutting of cortical bone

Cutting operations in bone are involved in surgical treatments in orthopaedics and traumatology. The importance of guaranteeing the absence of damage in the living workpiece is equivalent in this case to ensuring surface quality. The knowledge in this field is really far from the expertise in industrial cutting of mechanical components. Modeling of bone cutting is a challenge strongly dependent on the accurate modeling of mechanical behaviour of the bone. This paper focuses on modeling of orthogonal cutting of cortical bone. The intrinsic anisotropic nature of the cortical bone that makes it comparable to a composite material is taken into account. The influence of anisotropy is analysed comparing this behaviour with an isotropic approach. It is shown that both chip morphology and temperature are affected by the anisotropy of the cortical bone that acts as a workpiece.The authors acknowledge the financial support for the work to the Ministry of Economy and Competitiveness of Spain under the Project DPI2011-25999 and DPI2013-46643-R.Santiuste, C.; Rodríguez Millán, M.; Giner Maravilla, E.; Miguélez, H. (2014). The influence of anisotropy in numerical modelling of orthogonal cutting of cortical bone. Composite Structures. 116:423-431. doi:10.1016/j.compstruct.2014.05.031S42343111

Pharmaceutical And Biomedical Applications Of Affinity Chromatography: Recent Trends And Developments

Affinity chromatography is a separation technique that has become increasingly important in work with biological samples and pharmaceutical agents. This method is based on the use of a biologically-related agent as a stationary phase to selectively retain analytes or to study biological interactions. This review discusses the basic principles behind affinity chromatography and examines recent developments that have occurred in the use of this method for biomedical and pharmaceutical analysis. Techniques based on traditional affinity supports are discussed, but an emphasis is placed on methods in which affinity columns are used as part of HPLC systems or in combination with other analytical methods. General formats for affinity chromatography that are considered include step elution schemes, weak affinity chromatography, affinity extraction and affinity depletion. Specific separation techniques that are examined include lectin affinity chromatography, boronate affinity chromatography, immunoaffinity chromatography, and immobilized metal ion affinity chromatography. Approaches for the study of biological interactions by affinity chromatography are also presented, such as the measurement of equilibrium constants, rate constants, or competition and displacement effects. In addition, related developments in the use of immobilized enzyme reactors, molecularly imprinted polymers, dye ligands and aptamers are briefly considered

Increase in pediatric recurrent fever evaluations during the first year of the COVID-19 pandemic in North America

The impact of the COVID-19 pandemic on new diagnoses of recurrent fevers and autoinflammatory diseases is largely unknown. The Childhood Arthritis and Rheumatology Research Alliance (CARRA) PFAPA/AID Working Group aimed to investigate the impact of the COVID-19 pandemic on the number of pediatric patients evaluated for recurrent fevers and autoinflammatory diseases in North America. The absolute number of new outpatient visits and the proportion of these visits attributed to recurrent fever diagnoses during the pre-pandemic period (1 March 2019–29 February 2020) and the first year of the COVID-19 pandemic (1 March 2020–28 February 2021) were examined. Data were collected from 27 sites in the United States and Canada. Our results showed an increase in the absolute number of new visits for recurrent fever evaluations in 21 of 27 sites during the COVID-19 pandemic compared to the pre-pandemic period. The increase was observed across different geographic regions in North America. Additionally, the proportion of new visits to these centers for recurrent fever in relation to all new patient evaluations was significantly higher during the first year of the pandemic, increasing from 7.8% before the pandemic to 10.9% during the pandemic year (p < 0.001). Our findings showed that the first year of the COVID-19 pandemic was associated with a higher number of evaluations by pediatric subspecialists for recurrent fevers. Further research is needed to understand the reasons behind these findings and to explore non-infectious triggers for recurrent fevers in children

Study of influence parameters application layers TiO2 by ALD method on their adhesion to the mettalic substrate

W niniejszej pracy badano wpływ parametrów nanoszenia warstw TiO2 metodą ALD na ich adhezję do metalicznego podłoża. Warstwa TiO2została naniesiona na próbki wykonane ze stali nierdzewnej 316 LVM polerowane elektrochemicznie oraz mechanicznie. Warstwy nanoszono z wykorzystaniem różnych zespołów parametrów nanoszenia, jakimi były zmienna ilość cykli nanoszenia oraz zmienna temperatura procesu. W celu badania adhezji naniesionych warstw do podłoża wykorzystano metodę scratch test. Podsumowując, badania wykazały, że najkorzystniejszym zespołem własności mechanicznych charakteryzowały się warstwy TiO2naniesione na stal 316 LVM metodą ALD w temperaturze 300°C w czasie 500 cykli.In this study have been investigated influence of parameters applying layers of TiO2by ALD method on their adhesion to the metal substrate. TiO2 layers was applied on the samples made of stainless steel 316 LVM polished electrochemically and mechanically. To deposition layers was using different combination of parameters, which as first were a variable number of cycles of application and variable temperature of process. Next was tested adhesion to the substrate by use of scratch test. The results of studies shown that the best values of mechanical properties characterized samples with layer of TiO2 deposited on stainless steel by ALD method at temperature 300°C with 500 cycles

Biomechanical analysis of surgical drill - bone system

Zasadniczym celem prezentowanej pracy była analiza biomechaniczna układu wiertło chirurgiczne - kość udowa w warunkach symulujących proces wiercenia w kości. Opracowano model geometryczny wiertła chirurgicznego o zróżnicowanej geometrii ostrza (2κ1 = 90° i 2κ2 = 120°) oraz krążka symulującego kość udową. Obliczenia przeprowadzono dla wiertła wykonanego ze stali X39Cr13. Efektem zrealizowanej analizy było wyznaczenie stanu odkształceń i naprężeń zredukowanych w części roboczej wiertła w funkcji obciążenia siłą F = 20-100 N i prędkością obrotową n = 2000 obr/min.The aim of the work was determination of biomechanical analysis of a surgical drill - bone system in simulated conditions of drilling in a bone. Geometrical models of the surgical drill of diverse geometry of the edge (2κ1 = 90° and 2κ2 = 120°) and the disc simulating femur were worked out. Calculations were carried out for the drill made of martensitic Steel (X39Cr13). The effect of numerical analysis was determination of strains and stresses in working part of the drill as a functional of the applied loading F = 20-100 N and rotational speed n = 2000 rpm

The influence of steam sterilization process on physicochemical properties of steel 316 LVM with a layer of TiO2 deposited by ALD method

Celem pracy była ocena wpływu procesu sterylizacji parowej na własności fizykochemiczne umocnionej stali 316 LVM pokrytej warstwą TiO2metodą ALD z różną liczbą cykli nanoszenia (500, 1250, 2500). W celu oceny zjawisk zachodzących na powierzchni badanej stali przeprowadzono badania odporności na korozję wżerową oraz badanie z wykorzystaniem elektrochemicznej spektroskopii impedancyjnej. Badania realizowano w roztworze Ringera w temperaturze 37 ± 1oC. W przeprowadzonych badaniach korozyjnych wyznaczono krzywe polaryzacji anodowej, które każdorazowo charakteryzują się obecnością pętli histerezy świadczącej o zainicjowaniu korozji wżerowej w badanym materiale. Z kolei badanie EIS wykazały, że wzrost liczby cykli nanoszenia warstwy wpływa niekorzystnie na jej własności barierowe.This thesis focuses on the assessment of the impact of the steam sterilization process on the physicochemical properties of the strengthened steel 316LVM coated TiO2using ALD method with different number of cycles, namely 500, 1250 and 2500. In order to evaluate the phenomena occurring on the surface of the steel I run a pitting corrosion resistance test and another study using the EIS. The research is conducted in Ringer's solution at 37± 1°C. Thanks to the first test the curves of anodic polarization are drawn. These curves are characterized by the presence of the hysteresis loop, and these, in turn, indicate the initiation of pitting corrosion in the tested material. On the other hand, the EIS examination shows that the increase in the number of cycles has an adverse impact on the permeability of the layer