Conditions of Liquid Steel Treatment for Near Net‐Shape Casting Processes

Slab casting for hot rolled steel and strip casting using the twin roll casting (TRC) method are compared in terms of inclusions evolution. There are differences of the processes, mainly the use of casting flux in CC of slabs, or pool shapes and sizes in terms of TRC, particularly when roll diameters vary. The inclusion evolution of alumina in a low carbon steel grade was estimated. By modelling particle growth rate, coagulation and deposition, an ‘agglomeration index’ was created to describe the probability of clogging in the SEN. Similarly the growth of secondary alumina precipitation during cooling of the melt in the pool by Stokes collision and turbulent collision was estimated in terms of forming large particles which are able to float‐up. Influences of melt superheat or caster size were taken into account.     

Oxidation of oleuropein studied by EPR and spectrophotometry

The autoxidation at alkaline pH and enzymatic oxidation by mushroom tyrosinase of oleuropein, the dominant biophenol present in the fruits and leaves of Olea europea, was followed by both electron paramagnetic resonance (EPR) and absorption spectroscopy. For comparison, the same oxidation processes were applied to 4‐methylcatechol, a simple polyphenol present in olive mill wastewaters. EPR spectra of stable o‐semiquinone radicals produced during autoxidation at pH 12 and short‐lived o‐semiquinone free radicals produced during autoxidation at pH 9.0 or tyrosinase action and stabilized by chelation with a diamagnetic metal ion (Mg²⁺) were recorded for both polyphenols, and the corresponding hyperfine splitting constants were determined. The UV‐Vis spectral characteristics of the oxidation of polyphenols were highly dependent on the type of polyphenol, oxidant type and the pH of the reaction. The kinetic behavior of tyrosinase in the presence of oleuropein and 4‐methylcatechol was followed by recording spectral changes at 400 nm (absorption maximum) over time. The tysosinase activity with oleuropein showed a pronounced pH optimum at pH 6.5 and a minor one around pH 8. From the data analysis of the initial rate at pH 6.5, the kinetic parameters K_m = 0.34 ± 0.03 mM and V_max = 0.029 ± 0.002 ΔA₄₀₀ min^–1 were determined for oleuropein.     

Modern Teaching and Training in Metallurgical Engineering

This contribution deals with advanced educational technologies needed to equip customers from higher education institutions, research and industry with efficient tools supporting their work and operating new skills‐training methods. The challenges are reducing the training costs, improving quality and increasing the number of graduates in engineering departments. The concept of a Virtual Lab based on the combination of various teaching methods and tools is presented. Principles of mathematisation in metallurgical education and training are discussed. An example of online course designed in the form of Virtual Lab is demonstrated.     

Algorithms for processing the group K nearest-neighbor query on distributed frameworks

Distributed and Parallel Databases - Given two datasets of points (called Query and Training), the Group (K) Nearest-Neighbor (GKNN) query retrieves (K) points of the Training with the smallest sum...     

Testing and applications of a process model in the metallurgical production practice of ferronickel from laterites

A mathematical model of the electro-reduction furnace process (ERF process), for the production of ferronickel from laterite ores, has been tested at Larco's metallurgical plant at Larymna Greece. The theoretical predictions for the progress of the nickel reduction have been compared with the operational results. The tests were carried out in the ERF no. 2 of Larco's plant. The influence of the main process variables on the nickel recovery and nickel losses in the ERF slags have been investigated in conjunction with the variation of the analysis of the feed and the nickel content of the metal bath. The further application of the model to the metallurgical practice is discussed. According to the predictions of the model the further development of the process in the direction of the production of low-nickel ferronickel (Ni < 15%) is analyzed. The advantages of the production of low-nickel ferronickel are presented and the possibility of its straight conversion to nickel-bearing steel-grades is discussed.     

Miscibility behavior and formation mechanism of stabilized felodipine-polyvinylpyrrolidone amorphous solid dispersions

In the present study, solid dispersion systems of felodipine (FEL) with polyvinylpyrrolidone (PVP) were developed, in order to enhance solid state stability and release kinetics. The prepared systems were characterized by using Differential Scanning Calorimetry, X-Ray Diffraction, and Scanning Electron Microscopy techniques, while the interactions which take place were identified by using Fourier Transformation-Infrared Spectroscopy. Due to the formation of hydrogen bonds between the carbonyl group of PVP and the amino groups of FEL, transition of FEL from crystalline to amorphous state was achieved. The dispersion of FEL was found to be in nano-scale particle sizes and dependent on the FEL/PVP ratio. This modification leads to partial miscibility of the two components, as it was verified by DSC and optimal glass dispersion of FEL into the polymer matrix since no crystalline structure was detected with XRD. The above deformation has a significant effect on the dissolution enhancement and the release kinetics of FEL, as it causes the pattern to change from linear to logarithmic. An impressive optimization of the dissolution profile is observed corresponding to a rapid release of FEL in the system containing 10% w/w of FEL, releasing 100% in approximately 20 min. The particle size of dispersed FEL into PVP matrix could be classified as the main parameter affecting dissolution optimization. The mechanism of such enhancement consists of the lower energy required for the dissolution due to the amorphous transition and the fine dispersion, which leads to an optimal contact surface of the drug substance with the dissolution media. The prepared systems are stable during storage at 40 ± 1°C and relative humidity of 75 ± 5%. Addition of sodium docusate as surfactant does not affect the release kinetics, but only the initial burst due to its effect on the surface tension and wettability of the systems.     

Partial purification and characterization of peroxidase from olives (<Emphasis Type="Italic">Olea europaea</Emphasis> cv. Koroneiki)

The enzyme peroxidase (POD) activity was extracted from olives (Olea europaea cv. Koroneiki) and was partially purified by ammonium sulfate fractionation and gel permeation chromatography (Sephacryl S 300). Further characterization of the POD was performed using the ammonium sulfate purified fraction. POD showed a molecular mass of 44 ± 2 kDa and it expressed catalytic activity with 2,2′-azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS), N,N-dimethyl-p-phenylenediamine (DMPD) and some olive fruit phenols. However, the enzyme was found ineffective as regards the oxidation of oleuropein, the major polyphenol of olives, as well as with coumaric, ferulic, ascorbic and p-hydroxy benzoic acids. pH optimum of the peroxidase-catalyzed oxidation depended on the substrate used and it varied from 4.0 to 6.0. Olive peroxidase shows high thermal stability. Oleuropein, the major polyphenol of olives, drastically inhibited ABTS peroxidation by the POD preparation with an IC₅₀ value of 47 μM. The presence of POD enzyme activity in virgin olive oil samples was also confirmed.     

GOrevenge: a novel generic reverse engineering method for the identification of critical molecular players, through the use of ontologies

The ever-increasing use of ontologies in modern biological analysis and interpretation facilitates the understanding of the cellular procedures, their hierarchical organization, and their potential interactions at a system's level. Currently, the gene ontology serves as a paradigm, where through the annotation of whole genomes of certain organisms, genes subsets selected, either from high-throughput experiments or with an established pivotal role regarding the probed disease, can act as a starting point for the exploration of their underlying functional interconnections. This may also aid the elucidation of hidden regulatory mechanisms among genes. Reverse engineering the functional relevance of genes to specific cellular pathways and vice versa, through the exploitation of the inner structure of the ontological vocabularies, may help impart insight regarding the identification and prioritization of the critical role of specific genes. The proposed graph-theoretical method is showcased in a pancreatic cancer and a T-cell acute lymphoblastic leukemia gene set, incorporating edge and Resnik semantic similarity metrics, and systematically evaluated regarding its performance.     

Development and characterization of a digestion model based on olive oil microemulsions

Olive oil microemulsions were used as biomimetic model to simulate aspects of the digestion process in the small intestine. Hydrolytic activity of trypsin and alkaline phosphatase in microemulsions in the presence and in the absence of squalene and phenolic acids at pH 8.5 and 37°C was examined. In the case of trypsin kinetic constants were calculated and found K_m = 0.080 ± 0.002 mM and V_max = 3.8 × 10^?5 ± 0.06 × 10^?5 mM/s. When gallic acid and squalene were added, hydrolytic activity of trypsin was reduced to 77 ± 2% and 69 ± 3%, respectively. In the presence of o‐, m‐, and p‐coumaric acid, protocatechouic acid, and caffeic acid, enzymatic activity was increased up to 142 ± 6%. Hydrolytic activity of alkaline phosphatase was inhibited in the presence of squalene and phenolic acids. To evaluate the size of the dispersed aqueous droplets in the presence and in the absence of enzymes, substrates, and antioxidants, dynamic light scattering (DLS) measurements were carried out and diameters in the range of 8.9–13.4 nm were observed. Membrane flexibility and micropolarity were studied by electron paramagnetic resonance (EPR) spectroscopy. Rotational correlation time (τ_R), order parameter (S), and hyperfine splitting constant (A₀) of doxyl stearic acid in the microemulsions were calculated and found 2.06 ns, 0.17, and 14.30 G, respectively. These values were slightly affected in the presence of additives. Practical applications: The main aim of the present study is to enhance our understanding on the digestibility of proteins and lipids in the presence of food antioxidants suggesting an in vitro digestion model for hydrolases based on virgin olive oil microemulsions. The information generated in this study could potentially facilitate the design and development of novel functional food formulations based on food‐grade colloidal delivery systems. Since modification or fortification of different food products focusing on different areas of health concern are of growing interest among the various sectors of food industry, the proposed research results could be of particular interest.     

Clinical Perspectives of ERCC1 in Bladder Cancer

ERCC1 is a key regulator of nucleotide excision repair (NER) pathway that repairs bulky DNA adducts, including intrastrand DNA adducts and interstrand crosslinks (ICLs). Overexpression of ERCC1 has been linked to increased DNA repair capacity and platinum resistance in solid tumors. Multiple single nucleotide polymorphisms (SNPs) have been detected in ERCC1 gene that may affect ERCC1 protein expression. Platinum-based treatment remains the cornerstone of urothelial cancer treatment. Given the expanding application of neoadjuvant and adjuvant chemotherapy in locally advanced bladder cancer, there is an emerging need for biomarkers that could distinguish potential responders to cisplatin treatment. Extensive research has been done regarding the prognostic and predictive role of ERCC1 gene expression and polymorphisms in bladder cancer. Moreover, novel compounds have been recently developed to target ERCC1 protein function in order to maximize sensitivity to cisplatin. We aim to review all the existing literature regarding the role of the ERCC1 gene in bladder cancer and address future perspectives for its clinical application.