Characterization of a new laboratory ceramic product from industrial by-products as raw materials and caustic magnesia as additive

Στην εργασία αυτή παρουσιάζεται ένα νέο κεραμικό προϊόν που παράχθηκε από μίξη καυστικής μαγνησίας, που παρασκευάστηκε εργαστηριακά από υψηλής καθαρότητας μαγνησίτη, φυσικού πηλού καθώς και τέφρας πυθμένα και ερυθράς ιλύος, προϊόντα γνωστά για τις δυσμενείς περιβαλλοντικές επιπτώσεις τους. Έπειτα από δοκιμή ποικίλων συνταγών, συμπεράναμε ότι προσθήκη 5% καυστικής μαγνησίας στο κεραμικό προϊόν βελτιώνει τις μηχανικές επιδόσεις του. Αυτό αποδίδεται στο γεγονός ότι το περίκλαστο της καυστικής μαγνησίας σχηματίζει «λαιμούς», οι οποίοι ισχυροποιούν τους δεσμούς στη μικροδομή του κεραμικού, σε συνδυασμό με τον ταυτόχρονο σχηματισμό μικρών ποσοτήτων άμορφου υλικού και την ομοιογενή κατανομή των πόρων, που δημιουργούνται κατά την όπτηση. Με συνδυαστική μελέτη Περιθλασιμετρίας Ακτίνων Χ και Σαρωτικού Ηλεκτρονικού Μικροσκοπίου του κεραμικού υποδείχτηκε η παρουσία αναλλοίωτων φάσεων, προερχόμενων από τις πρώτες ύλες, καθώς και νεοσχηματισμένων κρυστάλλων αλβίτη και μαγνησιοφερρίτη. Τα αποτελέσματα της παρούσας μελέτης δείχνουν ότι η χρήση παραπροϊόντων μπορεί να είναι σημαντική και περιβαλλοντικά φιλική στην παραγωγή φτηνών δομικών κεραμικών.A new ceramic product is introduced by mixing caustic magnesia, produced in the laboratory from pure, high quality magnesite, and natural silt. Bottom ash and red mud, two well known environmentally hazardous industrial by-products, were also added in the mixture. After testing various recipes we concluded that addition of 5% caustic magnesia in the ceramic product greatly enhances its performance. Increase bonding of the ceramic microstructure is attributed to the formation of periclase necks, the concurrent formation of small quantities of amorphous material and the homogeneously distributed pores during the experimental firing of the mixture. Combined X-ray Diffractometry and Scanning Electron Microscopy of the ceramic product revealed the occurrence of unreactive phases, inherited by the raw materials, as well as newly-formed albite and magnesioferrite. Our results show that utilization of by-products may be important and environmental friendly materials in producing low cost ceramic building materials

ON THE METAMORPHIC MODIFICATION OF CR-SPINEL COMPOSITIONS FROM THE ULTRABASIC ROCKS OF THE PINDOS OPHIOLITE COMPLEX (NW GREECE)

Οι σερπεντινίτες και τα σερπεντινιωμένα υπερβασικά πετρώματα του οφιολιθικού συμπλέγματος της Πίνδου, Βορειοδυτική Ελλάδα, περιέχουν κόκκους χρωμιούχων σπινελίων που είναι συνήθως εξαλλοιωμένοι. Το εύρος της εξαλλοίωσης διαφέρει από κόκκο σε κόκκο και δύο τύποι εξαλλοίωσης μπορούν να διακριθούν. Συμφύσεις χρωμιούχου σπινελίου και χρωμιούχου μαγνητίτη είναι ο κυρίαρχος τύπος εξαλλοίωσης, ενώ προοδευτική εξαλλοίωση χρωμιούχου σπινελίου από σιδηρο-χρωμίτη σε συνδιασμό/ή όχι με την ανάπτυξη χρωμιούχου μαγνητίτη μπορεί να απαντά επίσης. Συγκριτικά με τους πυρήνες, τα περιθώρια αλλοίωσης είναι εμπλουτισμένα σε Fe και δείχνουν αυξημένα επίπεδα Cr# και στους δύο τύπους εξαλλοίωσης, αλλά είναι αποπτωχευμένα σε Mg και ΑΙ στο δεύτερο από αυτούς. Η κοινή συσχέτιση χρωμιούχου μαγνητίτη με σερπεντίνη και σιδηρο-χρωμίτη με χλωρίτη παρέχει πληροφορίες για το μεταμορφικό πλαίσιο σχηματισμού τους μέσω διαδικασιών που περιλαμβάνουν μετασωματικές διεργασίες που περιλαμβάνουν μηχανισμούς διάχυσης κατιόντωνSerpentinites and serpentinised ultramafic rocks from the Pindos ophiolite complex, northwestern Greece, contain Cr-spinel grains that are usually altered. The extent of alteration differs among Cr-spinels and two alteration trends can be distinguished. The most dominant is characterised by Cr-spinel overgrown by Cr-magnetite, while the second shows gradual replacement of Cr-spinel by ferrian chromite locally combined with Cr-magnetite development. Compared to cores, the altered rims are enriched in Fe and show elevated Cr# in both types of alteration, while they are impoverished in Mg and Al only at the second one. The common association of Crmagnetite with serpentine and ferrian chromite with chlorite provides insights to the metamorphic context of their formation through processes that include metasomatism by cation diffusion exchang

Critical evaluation of molecular tumour board outcomes following 2 years of clinical practice in a Comprehensive Cancer Centre

Recently, molecular tumour boards (MTBs) have been integrated into the clinical routine. Since their benefit remains debated, we assessed MTB outcomes in the Comprehensive Cancer Center Ostbayern (CCCO) from 2019 to 2021. Methods and results In total, 251 patients were included. Targeted sequencing was performed with PCR MSI-evaluation and immunohistochemistry for PD-L1, Her2, and mismatch repair enzymes. 125 treatment recommendations were given (49.8%). High-recommendation rates were achieved for intrahepatic cholangiocarcinoma (20/30, 66.7%) and gastric adenocarcinoma (10/16, 62.5%) as opposed to colorectal cancer (9/36, 25.0%) and pancreatic cancer (3/18, 16.7%). MTB therapies were administered in 47 (18.7%) patients, while 53 (21.1%) received alternative treatment regimens. Thus 37.6% of recommended MTB therapies were implemented (47/125 recommendations). The clinical benefit rate (complete + partial + mixed response + stable disease) was 50.0% for MTB and 63.8% for alternative treatments. PFS2/1 ratios were 34.6% and 16.1%, respectively. Significantly improved PFS could be achieved for m1A-tier-evidence-based MTB therapies (median 6.30 months) compared to alternative treatments (median 2.83 months; P = 0.0278). Conclusion The CCCO MTB yielded a considerable recommendation rate, particularly in cholangiocarcinoma patients. The discrepancy between the low-recommendation rates in colorectal and pancreatic cancer suggests the necessity of a weighted prioritisation of entities. High-tier recommendations should be implemented predominantly

Investigation of platinum-group minerals (PGM) from Pindos chromitites (Greece) using hydroseparation concentrates

9 pages, 8 figures, 6 tables.The Pindos ophiolite complex, located in northern Greece, hosts small podiform chromitites characterized by very low platinum group element (PGE) grades. PGE (excluding Os) analyses from four chromitite samples, collected for this study, are below 400 ppb. Consequently, we used the technique of hydroseparation to concentrate PGM from Pindos chromitites. More specifically, we investigated two separate composite samples from Pefki and Milia chromitites. The Pefki concentrate contains 67 PGM that include secondary Ru-bearing minerals, ruarsite (RuAsS), laurite (Ru,Os)S2, irarsite (Ir,Ru,Rh,Pt)AsS, alloys of Os–Ir–Ru, hollingworthite (Rh,Pt,Pd)AsS, paolovite (Pd2Sn), braggite (Pd,Pt,Ni)S, sperrylite (PtAs2) and four unnamed PGM, electrum (Au,Ag) and native silver. The investigation of the Milia concentrate yields fifty one grains of PGM including primary laurite, Os–Ir alloys, erlichmanite, secondary Ru-bearing minerals, irarsite, Ru-alloys, ruarsite and Ru-based metals sulphides. PGM occur as both single and polyphase particles in both concentrates. The bulk of mineralization for grains between 5 and 15 μm is finer-grained in Milia (64.7%) than in Pefki (41.8%). The latter concentrate hosts considerably more altered PGM grains than the former. The hydroseparation process has recovered significantly more, as well as novel, PGM grains than the in situ mineralogical examination of single chromitite samples from the neighboring Korydallos occurrence. Although, most of the PGM occur as free particles and in situ textural information is lost, single grain textural evidence is observed. The mineralogical and grain size differences between the two samples may reflect styles of mineralization and indicate significant remobilization of PGE in Pefki. The latter possibility is suggested by the presence of secondary PGM, which may be related to the different alteration processes that affect the Pefki and Milia chromitites. In summary, this study provides significant information on the particles, grain size and associations of PGM, which are critical with respect to the petrogenesis and mineral processing of these minerals.We would like to express our gratitude to two anonymous reviewers for their comments that helped to improve the content of this manuscript. We are also thankful to Dr. V. Knauf for his valuable comments on processing of the samples, and Bill Kotsopoulos at University of Patras for his help with the scanning electron microscope. Research was partly supported by the University of Patras, Karatheodoris Project B097, to TAG. Kapsiotis was also supported by the State Scholarship Foundation of Greece.Peer reviewe

Investigation of Platinum-Group Minerals (PGM) from Othrys Chromitites (Greece) Using Superpanning Concentrates

Platinum-group minerals were concentrated using superpanning from two composite chromitite samples, which were collected from two old mines within the Othrys ophiolite. This method allows for the recovery of a broad spectrum of these rare and fine-grained minerals, and helps to better identify them and interpret their origin. Major differences between the east and west Othrys ophiolites were determined, probably as a result of their different origin and evolution. Primary Os-, Ir-, and Ru-bearing platinum-group minerals (IPGM)-alloys and the Rh-, Pt- and Pd-bearing platinum-group minerals (PPGM) occur only in the east Othrys chromitite, indicating an evolution from initially low fS2 conditions at shallower mantle levels with the subsequent implication of a S-saturated ascending fluid. In contrast, the absence of primary IPGM-alloys in west Othrys chromitite indicates that S saturation had been attained. The presence of erlichmanite suggests that sulphur fugacity eventually increased significantly in both suites. Substantial fluctuations of a fluid phase, likely related to serpentinising fluids, modified the platinum-group minerals (PGM) assemblage of west Othrys, and resulted in a large diversity of secondary PGM minerals. The limited number of secondary species developed in the east Othrys indicate that secondary processes were also different in the two suites