Modulation of the Cardiac Myocyte Action Potential by the Magnesium-Sensitive TRPM6 and TRPM7-like Current.

The cardiac Mg2+-sensitive, TRPM6, and TRPM7-like channels remain undefined, especially with the uncertainty regarding TRPM6 expression in cardiomyocytes. Additionally, their contribution to the cardiac action potential (AP) profile is unclear. Immunofluorescence assays showed the expression of the TRPM6 and TRPM7 proteins in isolated pig atrial and ventricular cardiomyocytes, of which the expression was modulated by incubation in extracellular divalent cation-free conditions. In patch clamp studies of cells dialyzed with solutions containing zero intracellular Mg2+ concentration ([Mg2+]i) to activate the Mg2+-sensitive channels, raising extracellular [Mg2+] ([Mg2+]o) from the 0.9-mM baseline to 7.2 mM prolonged the AP duration (APD). In contrast, no such effect was observed in cells dialyzed with physiological [Mg2+]i. Under voltage clamp, in cells dialyzed with zero [Mg2+]i, depolarizing ramps induced an outward-rectifying current, which was suppressed by raising [Mg2+]o and was absent in cells dialyzed with physiological [Mg2+]i. In cells dialyzed with physiological [Mg2+]i, raising [Mg2+]o decreased the L-type Ca2+ current and the total delayed-rectifier current but had no effect on the APD. These results suggest a co-expression of the TRPM6 and TRPM7 proteins in cardiomyocytes, which are therefore the molecular candidates for the native cardiac Mg2+-sensitive channels, and also suggest that the cardiac Mg2+-sensitive current shortens the APD, with potential implications in arrhythmogenesis.

Transient protein-protein interface prediction: datasets, features, algorithms, and the RAD-T predictor.

BACKGROUND: Transient protein-protein interactions (PPIs), which underly most biological processes, are a prime target for therapeutic development. Immense progress has been made towards computational prediction of PPIs using methods such as protein docking and sequence analysis. However, docking generally requires high resolution structures of both of the binding partners and sequence analysis requires that a significant number of recurrent patterns exist for the identification of a potential binding site. Researchers have turned to machine learning to overcome some of the other methods' restrictions by generalising interface sites with sets of descriptive features. Best practices for dataset generation, features, and learning algorithms have not yet been identified or agreed upon, and an analysis of the overall efficacy of machine learning based PPI predictors is due, in order to highlight potential areas for improvement. RESULTS: The presence of unknown interaction sites as a result of limited knowledge about protein interactions in the testing set dramatically reduces prediction accuracy. Greater accuracy in labelling the data by enforcing higher interface site rates per domain resulted in an average 44% improvement across multiple machine learning algorithms. A set of 10 biologically unrelated proteins that were consistently predicted on with high accuracy emerged through our analysis. We identify seven features with the most predictive power over multiple datasets and machine learning algorithms. Through our analysis, we created a new predictor, RAD-T, that outperforms existing non-structurally specializing machine learning protein interface predictors, with an average 59% increase in MCC score on a dataset with a high number of interactions. CONCLUSION: Current methods of evaluating machine-learning based PPI predictors tend to undervalue their performance, which may be artificially decreased by the presence of un-identified interaction sites. Changes to predictors' training sets will be integral to the future progress of interface prediction by machine learning methods. We reveal the need for a larger test set of well studied proteins or domain-specific scoring algorithms to compensate for poor interaction site identification on proteins in general.

Influence of the Plastic Deformation Process on the Residual Stresses and Hardness of an Al-5Mg Alloy.

The service behavior of ductile metallic materials, when they have previously undergone technological plastic deformation, depends on the deformation conditions. These are represented, among others, by the deformation rate, the process temperature, the applied pressures, and the introduced stresses, as well as other process variables. The investigation of the mechanical properties obtained after plastic deformation is an important means that contains two characteristics: on the one hand, to determine to what extent the parameters of the technological manufacturing process influence the main characteristics of the final component; and, on the other hand, on the basis of these characteristics, to analyze whether the component subjected to plastic deformation will be able to function reliably and safely. In the present work, an experimental study was made of the residual stresses developed and hardnesses obtained both in the immediate vicinity of a highly plastically deformed area and in an area previously obtained by rolling, without additional plastic deformation. For the determination of the residual stresses, the tensiometric rosette drilling method was used. By determining the same quantities in a non-plastically deformed area, significant changes in the values of the two quantities in the plastically deformed area were found. An increase in the maximum principal normal stresses by approx. 60 MPa and an increase in the Rockwel hardness by approx. 10 HRC was found. A sample was taken from the area under a plastic deformed circular shape, and was analyzed microscopically.

Considerations on the Failure Mechanisms at Fatigue Loading of 1018 Steel Samples Coated with Wip-C1 by Cold Spray.

There are some important advantages presented by metal specimens coated with WIP-C1 (Ni/CrC)-type materials. However, given the coating methods and the stress under dynamic loads, there are issues that need to be taken into account, particularly in terms of the behavior at the interface between the two materials. Using standardized cylindrical 1018 steel specimens uniformly coated with WIP-C1 (Ni/CrC) by cold spraying, this study investigated the fatigue behavior of the specimen as a whole, focusing on the interface areas of the two materials. The fatigue life diagram is given, to a large extent, by the behavior of the base material. As a result, in this work, we have focused not so much on the fatigue behavior of the assembly as on the integrity of the coating material and the defects, failures, etc., that may occur at the interface after a certain number of cycles. The applied load was cyclic fatigue through alternating-symmetric cycles. Scanning optical microscopy was used to observe plastic deformations and crack propagation during the breakage process. It was found that both the base material zone and the cover material zone presented good performance when the maximum stresses were at low values. A fatigue durability curve was also plotted, showing a conventional appearance for a metallic material, slightly influenced by the destruction of the base material interface. At higher maximum stress and, consequently, to large strains, a series of destructions at the interface of the two materials, of different types, were observed and will be highlighted in the paper.

In Vitro and In Vivo Analysis of the Mg-Ca-Zn Biodegradable Alloys.

The objective of this work was to analyze the in vitro and in vivo tests of a novel Mg-based biodegradable alloy-Mg-0.5%Ca-with various amounts of Zn (0.5, 1, 1.5, 2.0, and 3.0 wt.%). In terms of in vitro biocompatibility, MTT and Calcein-AM cell viability assays, performed on the MG-63 cell line through the extract method, revealed that all five alloy extracts are non-cytotoxic at an extraction ratio of 0.025 g alloy per mL of cell culture medium. In the in vivo histological analysis, Mg-0.5Ca-1.5Zn demonstrated exceptional potential for stimulating bone remodeling and showed excellent biocompatibility. It was observed that Mg-0.5Ca-0.5Zn, Mg-0.5Ca-1.5Zn, and Mg-0.5Ca-3Zn displayed good biocompatibility. Furthermore, the histological examination highlighted the differentiation of periosteal cells into chondrocytes and subsequent bone tissue replacement through endochondral ossification. This process highlighted the importance of the initial implant's integrity and the role of the periosteum. In summary, Mg-0.5Ca-1.5Zn stands out as a promising candidate for bone regeneration and osseointegration, supported by both in vitro and in vivo findings.

Analysis of Chemical, Microstructural and Mechanical Properties of a CuAlBe Material Regarding Its Role as a Non-Sparking Material.

We developed and analyzed a novel non-sparking material based on CuAlBe for applications in potentially explosive environments. Using a master alloy of CuBe, an established material for anti-sparking tools used in oil fields, mines, or areas with potentially explosive gas accumulations, and pure Al, we used an Ar atmosphere induction furnace to obtain an alloy with ~10 wt% Al and ~2 wt% Be percentages and good chemical and structural homogeneity. The new material was tested in an explosive gaseous mixture (10% H2 or 6.5% CH4) under extremely strong wear for 16,000 cycles, and no hot sparks capable of igniting the environment were produced. The material was used in the form of hot-rolled plates obtained from melted ingots. The experimental results reflect the use of a suitable material for non-sparking tools. This material has good deformability during hot rolling, abnormal grain growth during deformation under heat treatment and special thermo-mechanical processing, and no high chemical composition variation. Additionally, there are slightly different corrosion resistance and mechanical properties between the melt and hot-rolled state of CuAlBe material. Through hot rolling, the material's corrosion resistance increased, reducing the chances of generating sparks capable of causing explosions.

Investigations on the Degradation Behavior of Processed FeMnSi-xCu Shape Memory Alloys.

A new functional Fe-30Mn-5Si-xCu (x = 1.5 and 2 wt%) biomaterial was obtained from the levitation induction melting process and evaluated as a biodegradable material. The degradation characteristics were assessed in vitro using immersion tests in simulated body fluid (SBF) at 37 ± 1 °C, evaluating mass loss, pH variation that occurred in the solution, open circuit potential (OCP), linear and cyclic potentiometry (LP and CP), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and nano-FTIR. To obtain plates as samples, the cast materials were thermo-mechanically processed by hot rolling. Dynamic mechanical analysis (DMA) was employed to evaluate the thermal properties of the smart material. Atomic force microscopy (AFM) was used to show the nanometric and microstructural changes during the hot rolling process and DMA solicitations. The type of corrosion identified was generalized corrosion, and over the first 3-5 days, an increase in mass was observed, caused by the compounds formed at the metal-solution interface. The formed compounds were identified mainly as oxides that passed into the immersion liquid. The degradation rate (DR) was obtained as a function of mass loss, sample surface area and immersion duration. The dynamic mechanical behavior and dimensions of the sample were evaluated after 14 days of immersion. The nanocompounds found on the surface after atmospheric corrosion and immersion in SBF were investigated with the Neaspec system using the nano-FTIR technique.

Applications of Recycled and Crushed Glass (RCG) as a Substitute for Natural Materials in Various Fields-A Review.

Glass is a substance that is present in most houses since glass-based items are made and consumed in relatively high quantities. This has led to the buildup of glass in concerning quantities all over the world, which is a problem for the environment. It is well known that glass has several advantageous physiochemical features that qualify it as an appropriate material for use in the construction industry as an aggregate. The features include being non-biodegradable, resistant to chemical assault, having low water absorption, having high hydraulic conductivity, having temperature-dependent ductility, having alterable particle gradation, and having a wide availability in a variety of forms and chemical compositions. Because of these qualities, glass has been used in various investigations and field tests conducted in civil engineering to evaluate its effectiveness as an engineering aggregate and to develop environmentally friendly management strategies for waste glass. These studies and research have utilized glass in various forms, such as fine recycled glass, medium recycled glass, coarse recycled glass, powdered glass, and glass-based geopolymers. This study focuses on research studies that present results on physicochemical, mechanical, and durability characteristics. These studies and research contain samples of pure glass or glass as replacement percentages in materials (0-100%), including but not limited to unbound granular materials (such as recycled concrete aggregates and crushed rock). In light of the information assembled in this review article, it is legitimate to claim that glass has strong promise as a material in various civil applications.

Analysis of the Effect of Fiber Orientation on Mechanical and Elastic Characteristics at Axial Stresses of GFRP Used in Wind Turbine Blades.

Due to its physical and mechanical properties, glass-fiber-reinforced polymer (GFRP) is utilized in wind turbine blades. The loads given to the blades of wind turbines, particularly those operating offshore, are relatively significant. In addition to the typical static stresses, there are also large dynamic stresses, which are mostly induced by wind-direction changes. When the maximum stresses resulting from fatigue loading change direction, the reinforcing directions of the material used to manufacture the wind turbine blades must also be considered. In this study, sandwich-reinforced GFRP materials were subjected to tensile testing in three directions. The parameters of the stress-strain curve were identified and identified based on the three orientations in which samples were cut from the original plate. Strain gauge sensors were utilized to establish the three-dimensional elasticity of a material. After a fracture was created by tensile stress, SEM images were taken to highlight the fracture's characteristics. Using finite element analyses, the stress-strain directions were determined. In accordance to the three orientations and the various reinforcements used, it was established that the wind turbine blades are operational.

Microstructural and Electrochemical Influence of Zn in MgCaZn Biodegradable Alloys.

In recent years, biodegradable materials have included magnesium alloys with homogenous disintegration and a controllable degradation rate. Utilized in medical applications, biodegradable materials based on magnesium have been widely explored throughout the years. It is well-known that alloying Mg with biocompatible and non-toxic elements increases the biodegradability of surgical alloys. The purpose of this study was to examine the microstructure and the electrochemical response (corrosion resistance) of a new experimental Mg-based biodegradable alloy-Mg-0.5%Ca with additions of Zn as follows: 0.5, 1.5, and 3.0 wt.% in order to control the corrosion rate. Immersion tests were performed for different periods in a simulated body fluid electrolyte solution at 37 °C, and the mass loss was appreciated in order to calculate the corrosion rate (CR). The investigation led to the discovery of a dendritic Mg solid solution, a lamellar Mg2Ca compound, and a MgZn2 intermetallic phase. Scanning electron microscopy, optical microscopy, and energy dispersive spectroscopy were used for surface analysis after the immersion and electro-corrosion resistance tests. The metallic and ceramic compounds that detached themselves from the sample and passed into the solution were evaluated using the SEM-EDS system. All samples presented a generalized electro-corrosion with anodic and cathodic reactions of similar intensity. The corrosion rate was similar regardless of the percentage of zinc, with a smaller value for a higher than 3 wt.% Zn percentage based on the more protective zinc oxide that appeared on the surface.

The Influence of Beverages on Resin Composites: An In Vitro Study.

Dental composites, through their structural diversity, represent the biomaterials frequently used in dental reconstructive therapy. The aim of our study was to observe the influence of different beverage environment conditions on seven types of obturation dental materials with different compositions. Our research focused on the surface modification analysis of the materials after the immersion in the different beverages; in this regard, we used the EDAX technique correlated with the energy-dispersive X-ray fluorescence (XRF). The pH of the drinks and that of the simulated saliva solution were determined by the titrimetric method, a sodium hydroxide solution 0.1 mol/dm3 was prepared and used for the titration. An amount of 5 mL of each analyzed solution was added to 15 mL of distilled water to obtain a dilution, to which 3 drops of phenolphthalein (as a color indicator-Phenolphthalein, 3,3-Bis(4-hydroxyphenyl)-1(3H)-isobenzofuranone, C20H14O4 Mw: 318.32, purchased from Merck) were added for each analysis. For each solution, the experiment was repeated three times in order to obtain accurate results. The results of our study materialized into a real plea for modifying the patients' behavior in terms of diet and preferences for acidic drinks, so that their quality-of-life valence can be improved by keeping the composite materials in a long-term unalterable state on the one hand; on the other hand, systemic damage can be prevented as well.

Analysis of Degradation Products of Biodegradable ZnMgY Alloy.

Biodegradable metallic materials are increasingly gaining ground in medical applications. Zn-based alloys show a degradation rate between those recorded for Mg-based materials with the fastest degradation rate and Fe-based materials with the slowest degradation rate. From the perspective of medical complications, it is essential to understand the size and nature of the degradation products developed from biodegradable materials, as well as the stage at which these residues are eliminated from the body. This paper presents investigations conducted on the corrosion/degradation products of an experimental material (ZnMgY alloy in cast and homogenized state) after immersion tests in three physiological solutions (Dulbecco's, Ringer's and simulated body fluid (SBF)). Scanning electron microscopy (SEM) was used to highlight the macroscopic and microscopic aspects of corrosion products and their effects on the surface. An X-ray energy dispersive detector (EDS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) provided general information about the compounds based on their non-metallic character. The pH of the electrolyte solution was recorded for 72 h during immersion. The pH variation of the solution confirmed the main reactions proposed for the corrosion of ZnMg. The agglomerations of corrosion products were on the micrometer scale, mainly oxides, hydroxides and carbonates or phosphates. The corrosion effects on the surface were homogeneously spread, with a tendency to connect and form cracks or larger corrosion zones, transforming the pitting corrosion pattern into a generalized one. It was noticed that the alloy's microstructure strongly influences the corrosion characteristics.

Heat Treatment and Dynamic Mechanical Analysis Strain Sweep Effects on the Phase Structure and Morphology of an Fe-28Mn-6Si-5Cr Shape Memory Alloy.

Fe-Mn-Si-based shape memory alloys (SMAs) have been extensively investigated since 1982 for various useful properties that enhance the development of different applications such as anti-seismic dampers for very tall buildings, pipe joints, or rail fasteners. In particular, the Fe-28Mn-6Si-5Cr (mass. %) alloy has been mainly used in vibration mitigation or self-adjustable axial displacement applications. Dynamic mechanical analysis (DMA), performed by strain sweeps (SS), enables the monitoring of the evolution of storage modulus and internal friction variations with increasing strain amplitudes at different constant frequencies and temperatures. Thus, applying dynamic bending with various frequencies and amplitudes that actually represents an isothermal mechanical treatment. In the present paper, an Fe-28Mn-6 Si-5Cr (mass. %) SMA was cast by ingot metallurgy, hot-rolled, and water quenched in order to obtain thermally induced martensite and avoid the occurrence of cooling cracks. The influence of the holding time, between 2 and 10 h, at 1050 °C and the effects of DMA-SS performed at three different frequencies were analyzed by a differential scanning calorimetry, an X-ray diffraction, and a scanning electron and atomic force microscopy. The effects of the holding time and mechanical treatment on the structure and morphology of martensite plates were corroborated with the results of the thermal analysis.

Interdisciplinary Research on Medieval Fresco Subjected to Degradation Processes in the Corbii de Piatra Cave Church.

This paper presents research on the degradation processes of the fresco painting in the cave church of Corbii de Piatra Hermitage under the influence of meteoric infiltration water and environmental factors. The medieval fresco dates from the end of the 13th century and the beginning of the 14th century, being painted on a sandstone wall. The infiltration of meteoric water through this wall, the temperature variations, the environment and the repeated wetting/drying processes determined the degradation of the fresco, resulting in its detachment from large surfaces. This research established correlations between the processes that take place, the structural transformations, the changes in composition and the adhesion of the fresco to the sandstone wall. The results have been made available to conservation and restoration specialists, in order to choose appropriate materials and technologies. This paper presents findings regarding the pictorial material and introduces new analysis techniques in research on the degradation processes of the fresco painting in the cave church of Corbii de Piatra Hermitage under the influence of meteoric infiltration water and environmental factors.

[Aspects of molecular immunology and immunogenetics in autoimmune uveitis]. / Aspecte de imunologie moleculara si imunogenetica în uveita autoimuna.

Generally speaking, the uveitis comprises a relative complex group of autoimmune diseases or other autoimmune associated illness. Until now, a little from molecular and cellular mechanisms are known in the autoimmunity of uveitis. The uveitis may cause a visual handicap as well, leading even to blindness. This paper tries to bring into focus some of the molecular mechanisms and immunogenetic features of the disease.

Biosorption Potential of Microbial and Residual Biomass of Saccharomyces pastorianus Immobilized in Calcium Alginate Matrix for Pharmaceuticals Removal from Aqueous Solutions.

Two types of biosorbents, based on Saccharomyces pastorianus immobilized in calcium alginate, were studied for the removal of pharmaceuticals from aqueous solutions. Synthetized biocomposite materials were characterized chemically and morphologically, both before and after simulated biosorption. Ethacridine lactate (EL) was chosen as a target molecule. The process performance was interpreted as a function of initial solution pH, biosorbent dose, and initial pharmaceutical concentration. The results exhibited that the removal efficiencies were superior to 90% for both biosorbents, at the initial pH value of 4.0 and biosorbent dose of 2 g/L for all EL initial concentrations tested. Freundlich, Temkin, Hill, Redlich-Peterson, Sips, and Toth isotherms were used to describe the experimental results. The kinetic data were analyzed using kinetic models, such as pseudo-first order, pseudo-second order, Elovich, and Avrami, to determine the kinetic parameters and describe the transport mechanisms of EL from aqueous solution onto biosorbents. Among the tested equations, the best fit is ensured by the pseudo-second-order kinetics model for both biosorbents, with the correlation coefficient having values higher than 0.996. The many potential advantages and good biosorptive capacity of Saccharomyces pastorianus biomass immobilized in calcium alginate recommend these types of biocomposite materials for the removal of pharmaceuticals from aqueous solutions.

Structural Testing by Torsion of Scalable Wind Turbine Blades.

In life service, the wind turbine blades are subjected to compound loading: torsion, bending, and traction, all these resulting in the occurrence of normal and tangential stresses. At some points, the equivalent stresses, due to overlapping effects provided by normal and shear stresses, can have high values, close to those for which the structure can reach to the failure point. If the effects of erosion and clashes with foreign bodies are added, the structure of the blade may lose its integrity. Considering both the complex shape of the blade and internal structure used, the mechanical behavior of the blade, such as the rigidity and resistance along the length of the blade, are usually determined with some uncertainty. This paper presents the results obtained in the non-destructive tests at static torsion of a scalable wind turbine blade. The objective of the paper was to determine the variation of the equivalent stress in the most stressed points of the blade, in relation to the torques applied. To determine the points with the highest stress, a finite element analysis was performed on the scalable wind turbine blade. Electrotensiometric transducers were mounted at different points of the blade, determining the main stresses in the respective points, as well as their variation during the torsion test, by subsequent calculations. The determinations were performed by applying the torque in both senses, in relation to the blade axis, thus concluding the values of the equivalent stress in the two cases.

Evaluation of the Fatigue Behaviour and Failure Mechanisms of 52100 Steel Coated with WIP-C1 (Ni/CrC) by Cold Spray.

Cold spray technique has been major improved in the last decades, for studying new properties for metals and alloys of aluminum, copper, nickel, and titanium, as well as steels, stainless steel and other types of alloys. Cold sprayed Ni/CrC coatings have the potential to provide a barrier as well as improved protection to steels. Fatigue characteristics of 52100 steel coated with Ni/Chrome-Carbide (Ni/CrC) powder mixture by using cold gas dynamic spray are investigated. Fatigue samples were subjected to symmetrically alternating, axially applied cyclic fatigue loading until failure. The test was stopped if a sample survived more than 5 × 106 cycles at the applied stress. Fracture surfaces for each sample were examined to investigate the behaviour of the coating both at high stress levels and at a high number of stress cycles. Scanning electron microscopy was used to assess the damage in the interface of the two materials. Good fatigue behaviour of the coating material was observed, especially at low stresses and a high number of cycles. Details of the crack initiation region, the stable crack propagation region and the sudden crack expansion region are identified for each sample. In most of the samples, the initiation of the crack occurred on the surface of the base material and propagated into the coating material. The possible effects of coatings on the initial deterioration of the base material and the reduction of the lifespan of the coated system were also investigated. The aim of the paper was to study the interface between the base material and the coating material at the fatigue analysis for different stresses, highlighting the appearance of cracks and the number of breaking cycles required for each sample.

Evaluation of the Fatigue Behavior and Failure Mechanisms of 4340 Steel Coated with WIP-C1 (Ni/CrC) by Cold Spray.

Fatigue behavior of standardized 4340 steel samples uniformly coated with WIP-C1 (Ni/CrC) by cold spray was investigated. In particular, when a crack appeared at the interface between the base material and the coating, the cause of it as well as its shape and size were investigated. Fatigue loading was applied by alternating symmetrical cycles. Scanning electron microscopy was used to study the onset of failure and the subsequent propagation of cracks. The interface between the two materials performed well-in all samples, the initial crack propagation occurred on the surface of the base material, continuing into the coating material and in the interior of the base material. The fatigue durability curve of stress vs. number of cycles (S-N) presented a conventional form for a metallic alloy and the coating material had an influence only on the damage on the surface of the base material.

Microstructural, Corrosion Resistance, and Tribological Properties of Al2O3 Coatings Prepared by Atmospheric Plasma Spraying.

An usual material, EN-GJL-250 cast iron, used for automotive braking systems, was covered with a ceramic material (105NS-1 aluminium oxide) using an industrial deposition system (Sulzer Metco). The main reason was to improve the corrosion and wear (friction) resistance properties of the cast-iron. Samples were prepared by mechanical grinding and sandblasting before the deposition. We applied two and four passes (around 12-15 µm by layer) each at 90° obtaining ceramic coatings of 30 respectively 60 µm. The surface of the samples (with ceramic coatings) was investigated using scanning electron microscopy (SEM), dispersive energy spectroscopy (EDS) and X-ray diffraction (XRD). Scratch and micro-hardness tests were performed using CETR-UMT-2 micro-tribometer equipment. The better corrosion resistance of the base material was obtained by applying the ceramic coating. The results present a better corrosion resistance and a higher coefficient of friction of the coated samples.