Modification of Biocorrosion and Cellular Response of Magnesium Alloy WE43 by Multiaxial Deformation

The study shows that multiaxial deformation (MAD) treatment leads to grain refinement in magnesium alloy WE43. Compared to the initial state, the MAD-processed alloy exhibited smoother biocorrosion dynamics in a fetal bovine serum and in a complete cell growth medium. Examination by microCT demonstrated retardation of the decline in the alloy volume and the Hounsfield unit values. An attendant reduction in the rate of accumulation of the biodegradation products in the immersion medium, a less pronounced alkalization, and inhibited sedimentation of biodegradation products on the surface of the alloy were observed after MAD. These effects were accompanied with an increase in the osteogenic mesenchymal stromal cell viability on the alloy surface and in a medium containing their extracts. It is expected that the more orderly dynamics of biodegradation of the WE43 alloy after MAD and the stimulation of cell colonization will effectively promote stable osteosynthesis, making repeat implant extraction surgeries unnecessary.

In Vitro Investigation on Degradable Mg-Based Biomaterial under the Impact of the Serum Glycoprotein Fetuin

Biomedical applications of magnesium (Mg) and its alloys are generally dependent on their degradation behavior in vivo. Despite its attractive properties, which make Mg suitable for orthopedic applications, the in vivo material-tissue (bone, blood, and lymph tissues) interaction is not yet fully understood. To investigate the influence of major serum proteins on the degradation, this study focused on fetuin, which is one of the major non-collagenous plasma proteins and which is essential for biomineralization. This study used a physiological setup to investigate the influence of fetuin on the degradation behavior of pure Mg in the presence of calcium (Ca). Extruded pure Mg samples were immersed under cell culture conditions in Hank’s balanced salt solution (HBSS) under defined Ca regimes. The results showed a significant decrease in the degradation rate (DR) when both fetuin and Ca were present in an immersion medium as compared to media where they were not simultaneously present. A possible reason for this behavior was the forming of a dense, protein-degradation products protection barrier at the material surface. Furthermore, the limitation of freely available Ca might be a reason for a decreased degradation. The cultivation of primary osteoblasts (pOB) was possible at the fetuin-coated Mg-surface without additional serum supplementation.

In Vitro Nitrogen Transformations by Pollen From Temperate Tree Species

The effects of pollen on dissolved inorganic nitrogen (DIN) compounds in throughfall water are not completely understood. We conducted a 7-day leaching experiment with pollen from silver birch (including a sterilized control), European beech, sessile oak, Scots pine, Corsican black pine and Norway spruce using an immersion medium containing nitrate (11.295 mg N l-1). Within 2 hours, pollen released substantial amounts of potassium (K+), phosphate (PO3-) and organic compounds. Solute concentrations of ammonium (NH4+) were built up over time. In treatments with pollen from birch, oak and beech, nitrate (NO3-) concentrations started to decrease after 24–48 hours, while simultaneously nitrite (NO2-) emerged, but part of the inorganic nitrogen could no longer be detected in solution. For birch, sterilisation of the pollen made no difference, indicating that microorganisms on the pollen played no substantial role in the observed N transformations. Conditions in the samples were oxic (1.82–6.12 mg O2 l-1), rendering microbial denitrification unlikely. Our findings revealed that pollen from broadleaved deciduous trees can transform throughfall NO3- into NO2- and likely also nitric oxide (NO), probably through the nitrate reductase pathway. The synthesis of NH4+ might be part of a natural defence mechanism protecting reproductive organs against pathogens during pollination.

Biofilm Formation and Bio Corrosion of Carbon Steel in Diesel-Biodiesel Storage Tank

Biodiesel is potential to blend with petroleum diesel as an alternative blended fuel. Biodiesel is usually stored in carbon steel storage tank which easily corroded by microorganisms. Microorganisms can use blended fuels as carbon source and water from biodiesel which is hygroscopic for growth and metabolism. Thus, degradation of fuel may occur and lead to biocorrosion by microorganisms such as Bacillus megaterium. This research was conducted to determine the effect of biodiesel concentration of blended fuel on biofilm formation and biocorrosion by Bacillus megaterium. The experiments were carried out by immersing carbon steel specimens in immersion medium for 21 days with variation of biodiesel concentration (B0, B20, B30, and B100). Biofilms that form on the metal surface cause areas with non-uniform oxygen concentrations and form anodic/cathodic conditions, raised to potential differences and biocorrosion occurred. The average corrosion rates were 0,035 ± 0,03; 0,533 ± 0,33; 0,642 ± 0,28; 0,109 ± 0,04 mm/year achieved by B0, B20, B30 and B100 respectively. These rates increased when compared to the control medium. Microorganism activity also caused damage to the metal surface by forming pitting corrosion on B30 and B100.

Ion Release from Dental Implants, Prosthetic Abutments and Crowns under Physiological and Acidic Conditions

Ion release from dental implants and prosthetic restoration can affect osteointegration and implant viability over a long period of time. Therefore, the aim of this study was to study the ion release from implants and crowns, with and without intermediate anodized abutments, in two different media, simulating clinical conditions. The implants, intermediate prosthetic abutments and Cr–Co crowns were divided into two groups depending on the media: Hanks’ solution and 1% lactic acid, simulating body fluids and microbiologically conditioned fluids, respectively. The study followed the ISO 10271:2011 and 10993-15:2000 standards modified to simulate the replacement of fluids in the oral environment. The ions’ release was measured by inductively coupled plasma mass spectroscopy (ICP-EOS), and only aluminum, chromium, cobalt, titanium and vanadium were identified. Ion concentration was higher in lactic acid than in Hanks’ solution at all time points (p < 0.05). Only vanadium showed a very low ion release in lactic acid, with no statistically significant differences from the ion release in Hanks’ solution (p = 0.524). Both anodized abutments and the immersion medium influenced the release of ions and affected the corrosion of these structures. The presence of an intermediate anodized abutment also affected ion release, as the level of ions was lower in groups with this component.

Open-top axially swept light sheet microscopy

Open-top light sheet microscopy (OT-LSM) is a specialized microscopy for the high throughput cellular imaging of large tissues including optically cleared tissues by having all the optical setup below the sample stage. Current OT-LSM systems had relatively low axial resolutions by using weakly focused light sheets to cover the imaging field of view (FOV). In this report, open-top axially swept LSM (OTAS-LSM) was developed for high-throughput cellular imaging with the improved axial resolution. OTAS-LSM swept the tightly focused excitation light sheet across the imaging FOV by using an electro tunable lens (ETL) and collected emission light at the focus of light sheet with a camera in the rolling shutter mode. OTAS-LSM was developed by using air objective lenses and a water prism for simplicity and it had on-axis optical aberration associated with the mismatch of refractive indices between air and immersion medium. The effects of optical aberration were analyzed by both simulation and experiment. The image resolutions were 1.5-1.6μm, and approximately 140% of the aberration-free theoretical values. The newly developed OTAS-LSM was applied to the imaging of optically cleared mouse brain and small intestine and it could visualize neuronal networks in the single cell level. OTAS-LSM might be useful for the high-throughput cellular examination of optically cleared large tissues.

Comparative analysis of the effectiveness of «Chaos and Clues», «Triage Amalgamated Dermoscopic Algorithm» dermatoscopic algorithms and BLINСK techniques in the diagnosis of melanoma and other skin cancers depending on previous dermatoscopy experience

Aim.Comparison of the results of the use of dermatoscopic algorithms Chaos and Clues, Triage Amalgamated Dermoscopic Algorithm (TADA) and BLINCK technique in the diagnosis of melanoma and other malignant skin tumors depending on the presence of previous dermatoscopy experience. Materials and methods.Algorithms were tested on 85 patients with 85 skin formations who visited the polyclinic of Kursk Regional Clinical Oncology Clinic in 20172019. The average age of the patients was 54.8 years old. Dermatoscopy was performed by the non-polarized dermatoscope HEINE mini 3000, photo documentation by the Canon PowerShot SX540 HS camera. Immersion medium ethyl alcohol (conc. 70%). Patients were carefully examined physiologically and clinically. A clinical and epiluminescence pattern of all neoplasms was obtained, their morphological examination was performed. For the research 2 groups of 3 participants were formed based on the criterion of previous dermatoscopy experience. Each algorithm was evaluated by objective (sensitivity, specificity) and subjective (speed, convenience) criteria. The dermatoscopic results obtained by the techniques used were compared to the histological findings. Results. Using algorithms by a group having previous dermatoscopy experience, the following results were obtained: in the method Chaos and Clues sensitivity 93.753.3%, specificity 77.44.6%, speed 3 points, convenience 3 points. TADA sensitivity 96.82.2%, specificity 79.24.8%, speed 4 points, convenience 5 points. BLINCK sensitivity 96.82.2% specificity 77.44.6%, speed 4 points, convenience 5 points. In the group with no previous dermatoscopy experience, the results were as follows: in the Chaos and Clues algorithm, sensitivity 93.753.3%, specificity 62.35.7%, speed 3 points, convenience 3 points. TADA sensitivity 84.44.6%, specificity 64.25.8%, speed 4 points, convenience 5 points; BLINCK sensitivity 80.64.4%, specificity 77.44.6%, speed 5 points, convenience 4 points. Thus, these algorithms can be used in the diagnosis of malignant skin neoplasms. At the same time, individuals with no experience of dermatoscopy are encouraged to use the Chaos and Clues algorithm. In a group having experience in dermatoscopy, both the TADA and the BLINCK technique can be used equally.

Effect of Immersion Mediums on the Structural and Thermal Properties of [EP/Zr02-Y203] Nanocomposites

This research studies is the effects of the chemical solutions on the structural properties and thermal conductivity of the nanocomposite materials. Samples were prepared via the hand lay-up molding method, using epoxy resin as a matrix and a variety of weight ratios of the nanoceramic powder (Zirconia- Yttria) as a reinforcement material with different weight ratios,using hand lay-up molding method. Distilled water H20 and diluted HCl and Na0H solutions were used as immersion mediums. Surface roughness, granularity cumulating distribution and thermal conductivity were investigated. The results showed an increase in the surface roughness and changes in the granularity cumulating distribution and thermal conductivity that were dependent on the type of immersion medium used, as well as on the addition ratio of Zirconia-Yttria.