Geochemical exploration of the three most significant geothermal areas of Lesbos Island, Greece

Lesbos Island has several thermal manifestations linked to extensional active faults that act as channels for the ascent of deep thermal fluids.The present work describes detailed geochemical exploration aimed at evaluating the potential of the Lesbos Island geothermal resource. Exploration was carried out on the three sites (Kalloni-Stipsi, Petra-Argenos and Polichnitos) that have the most favourable hydrogeological and structural setting on the island.Hydrogeochemical data reveal the presence between Kalloni and Stipsi of a shallow thermal aquifer with temperatures below boiling point, which coincides with carbon dioxide and temperature anomalies in the overlying groundwaters. All the thermal waters in the study area have fairly similar physico-chemical features; their geochemical temperature is in the range 115–125°C. While low-medium enthalpy geothermal resources are relatively abundant in the three selected areas of Lesbos Island, the presence of a high enthalpy geothermal system is still the subject of debate.     

Solar assisted heat pump on air collectors: A simulation tool

The heating system of the bioclimatic building of the Greek National Centre for Renewable Energy Sources (CRES) comprises two heating plants: the first one includes an air source heat pump, Solar Air Collectors (SACs) and a heat distribution system (comprising a fan coil unit network); the second one is, mainly, a geothermal heat pump unit to cover the ground floor thermal needs. The SAC configuration as well as the fraction of the building heating load covered by the heating plant are assessed in two operation modes; the direct (hot air from the collectors is supplied directly to the heated space) and the indirect mode (warm air from the SAC or its mixture with ambient air is not supplied directly to the heated space but indirectly into the evaporator of the air source heat pump). The technique of the indirect mode of heating aims at maximizing the efficiency of the SAC, saving electrical power consumed by the compressor of the heat pump, and therefore, at optimizing the coefficient of performance (COP) of the heat pump due to the increased intake of ambient thermal energy by means of the SAC. Results are given for three research objectives: assessment of the heat pump efficiency whether in direct or indirect heating mode; Assessment of the overall heating plant efficiency on a daily or hourly basis; Assessment of the credibility of the suggested simulation model TSAGAIR by comparing its results with the TRNSYS ones.     

Numerical investigation of Solid Recovered Fuels’ co-firing with brown coal in large scale boilers – Evaluation of different co-combustion modes

In the current work the co-combustion of Solid Recovered Fuels’ (SRFs’) with brown coal in large scale pulverised coal boilers under different operational conditions is numerically investigated. In order to overcome the difficulty of the complex, inhomogeneous nature of waste recovered fuels, SRF is modelled as a mixture of two different fractions, the biogenic and the plastic one. For each fraction different combustion mechanisms are presented, whilst for the first time the proposed combustion mechanism of the plastic fraction is incorporated in a commercial CFD code and validated against available experimental data. A 600 MW_e brown coal boiler is simulated as a reference and its operational characteristics are compared with parameterised scenarios of SRF co-firing conditions. Based on the numerical results, the optimum co-firing concepts regarding the more efficient operation of the boiler (hot spots and fuel’s burnout) are identified, decreasing the environmental impact of the boiler’s emissions.     

Modelling of low temperature wine-making,using immobilized cells

A new biocatalyst was prepared by immobilization of Saccharomyces cerevisiae AXAZ-1 yeast cells on whole corn grains. This biocatalyst was used for 30 repeated batch fermentations of glucose and grape musts at various temperatures. The biocatalyst retained its operational stability for a long period and it proved able to produce dry wines of fine clarity, even at extremely low temperatures (5 °C). The produced wines were analyzed for volatile byproducts by GC and GC–MS. The results showed an increase in the number and amount of esters produced when immobilized cells were used. In addition, an increase in the percentages of esters and a decrease in those of alcohols with the decrease of fermentation temperature were observed. Finally a model, appropriate for describing sugar consumption and the simultaneous ethanol formation by immobilized cells, was proposed. The results of this model fit almost perfectly with the experimental data.     

Gastrointestinal Stromal Tumors (GISTs): Novel Therapeutic Strategies with Immunotherapy and Small Molecules

Gastrointestinal stromal tumors (GISTs) are the most common types of malignant mesenchymal tumors in the gastrointestinal tract, with an estimated incidence of 1.5/100.000 per year and 1–2% of gastrointestinal neoplasms. About 75–80% of patients have mutations in the KIT gene in exons 9, 11, 13, 14, 17, and 5–10% of patients have mutations in the platelet-derived growth factor receptor a (PDGFRA) gene in exons 12, 14, 18. Moreover, 10–15% of patients have no mutations and are classified as wild type GIST. The treatment for metastatic or unresectable GISTs includes imatinib, sunitinib, and regorafenib. So far, GIST therapies have raised great expectations and offered patients a better quality of life, but increased pharmacological resistance to tyrosine kinase inhibitors is often observed. New treatment options have emerged, with ripretinib, avapritinib, and cabozantinib getting approvals for these tumors. Nowadays, immune checkpoint inhibitors form a new landscape in cancer therapeutics and have already shown remarkable responses in various tumors. Studies in melanoma, non-small-cell lung cancer, and renal cell carcinoma are very encouraging as these inhibitors have increased survival rates. The purpose of this review is to present alternative approaches for the treatment of the GIST patients, such as combinations of immunotherapy and novel inhibitors with traditional therapies (tyrosine kinase inhibitors).     

Bacterial Cellulose Production from Industrial Waste and by-Product Streams

The utilization of fermentation media derived from waste and by-product streams from biodiesel and confectionery industries could lead to highly efficient production of bacterial cellulose. Batch fermentations with the bacterial strain Komagataeibacter sucrofermentans DSM (Deutsche Sammlung von Mikroorganismen) 15973 were initially carried out in synthetic media using commercial sugars and crude glycerol. The highest bacterial cellulose concentration was achieved when crude glycerol (3.2 g/L) and commercial sucrose (4.9 g/L) were used. The combination of crude glycerol and sunflower meal hydrolysates as the sole fermentation media resulted in bacterial cellulose production of 13.3 g/L. Similar results (13 g/L) were obtained when flour-rich hydrolysates produced from confectionery industry waste streams were used. The properties of bacterial celluloses developed when different fermentation media were used showed water holding capacities of 102–138 g·water/g·dry bacterial cellulose, viscosities of 4.7–9.3 dL/g, degree of polymerization of 1889.1–2672.8, stress at break of 72.3–139.5 MPa and Young’s modulus of 0.97–1.64 GPa. This study demonstrated that by-product streams from the biodiesel industry and waste streams from confectionery industries could be used as the sole sources of nutrients for the production of bacterial cellulose with similar properties as those produced with commercial sources of nutrients.     

A 3D fibre beam-column element with shear modelling for the inelastic analysis of steel structures

A force-based fiber beam-column element is proposed for the capacity assessment of frame structures under high shear. The proposed element is suitable for the performance assessment of large scale steel structures, which are not flexure-dominated. The element formulation follows the assumptions of the Timoshenko beam theory, while its kinematics are obtained through the natural-mode method. The element state-determination phase, instead of uniaxial material laws, typically associated with fiber elements, is based on a three-dimensional law taking into consideration the interaction between axial, bending, shear and torsion. Numerical examples are presented confirming the accuracy and the computational efficiency of the proposed formulation under monotonic, cyclic and dynamic/seismic loading. Compared to experimental results and the results of detailed finite element models, excellent agreement is achieved.     

Investigation of Magnetotaxis of Reconfigurable Micro‐Origami Swimmers with Competitive and Cooperative Anisotropy

Recent advances in magnetic nanocomposites have enabled untethered micromachines with controllable shape transformations and programmable magnetic anisotropy, paving the way for a variety of biomedical applications using soft microrobots. Magnetic anisotropy is programmed by assembling the embedded magnetic nanoparticles (MNPs) in polymeric materials to overcome the shape anisotropy of a given structure. However, this approach is questionably effective in reconfigurable structures, as shape changes naturally result in rearrangement of the embedded MNPs. A naturally occurring solution to this problem is found in magnetotactic bacteria, which build chains of MNPs in a linear‐chain formation in their cells to create a permanent magnetic dipole moment. This dipole moment enables them to actively sense magnetic fields and coordinate their movement in response, a behavior called magnetotaxis. Inspired by this, self‐folding micro‐origami swimmers comprising magnetic nanocomposite bilayer structures that exhibit controllable shape transformations and programmable, shape‐independent magnetotaxis is fabricated. A study of these structures reveals that their magnetic anisotropy results from competition or cooperation between anisotropy of assembled chains of MNPs and overall shape anisotropy. Moreover, how the magnetotaxis of the reconfigurable micro‐origami swimmers depends only on the embedded permanent dipole moment, independent of the overall magnetic anisotropy, is demonstrated.     

Multimedia search and retrieval using multimodal annotation propagation and indexing techniques

In this paper, a complete solution for search and retrieval of rich multimedia content over modern databases is presented. The framework proposed in this paper combines the advantages of multimodal search with those of annotation propagation into a unified system. Moreover, an effective technique, which is appropriate for large-scale indexing, is adopted, extended and integrated to the proposed framework so as to achieve optimized search and retrieval of rich media content even from large-scale databases.