Publications by authors named "Alexopoulos K"

Developing improved zeolites is essential in novel sustainable processes such as the catalytic pyrolysis of plastic waste. This study used density functional theory to investigate how alkyl chain length, unsaturated bonds, and branching affect β-scission kinetics in four zeolite frameworks, a key reaction in hydrocarbon cracking. The activation enthalpy was evaluated for a wide variety of 23 hydrocarbons, with 6 to 12 carbon atoms, in FAU, MFI, MOR, and TON.

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Referred chronic shoulder pain may arise from diaphragmatic irritation. It can potentially be alleviated by blockade of the phrenic nerve. There is literature describing its use in acute pain conditions; yet for chronic pain, there are no reports.

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Ni can be used as a catalyst for dry reforming of methane (DRM), replacing more expensive and less abundant noble metal catalysts (Pt, Pd, and Rh) with little sacrifice in activity. Ni catalysts deactivate quickly under realistic DRM conditions. Rare earth oxides such as CeO, or as CeO-ZrO-AlO (CZA), are supports that improve both the activity and stability of Ni DRM systems due to their redox activity.

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The production of multivariate time-series data facilitates the continuous monitoring of production assets. The modelling approach of multivariate time series can reveal the ways in which parameters evolve as well as the influences amongst themselves. These data can be used in tandem with artificial intelligence methods to create insight on the condition of production equipment, hence potentially increasing the sustainability of existing manufacturing and production systems, by optimizing resource utilization, waste, and production downtime.

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Volatility and uncertainty of today's value chains along with the market's demands for low-batch customized products mandate production systems to become smarter and more resilient, dynamically and even autonomously adapting to both external and internal disturbances. Such resilient behavior can be partially enabled by highly interconnected Cyber-Physical Production Systems (CPPS) incorporating advanced Artificial Intelligence (AI) technologies. Multi-agent solutions can provide better planning and control, improving flexibility and responsiveness in production systems.

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CuO-based catalysts are active for the oxygen evolution reaction (OER), although the active form of copper for the OER is still unknown. We combine operando Raman experiments and density functional theory (DFT) electronic structure calculations to determine the form of Cu()OH present under OER conditions. Raman spectra show a distinct feature related to the active "Cu" species, which is only present under highly oxidizing conditions.

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Little is known about manta ray population size, structure and connectivity in the Philippines. In collaboration with dive operators, non-governmental organizations and authorities, sightings of manta rays were collated into a single national database. Using in-water photographs and videos gathered through citizen science and dedicated research efforts, this study compiled sightings between 2004 and 2020, showing 22 separate sites throughout the archipelago with manta rays present.

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Conventional thermochemical syntheses by continuous heating under near-equilibrium conditions face critical challenges in improving the synthesis rate, selectivity, catalyst stability and energy efficiency, owing to the lack of temporal control over the reaction temperature and time, and thus the reaction pathways. As an alternative, we present a non-equilibrium, continuous synthesis technique that uses pulsed heating and quenching (for example, 0.02 s on, 1.

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Condition monitoring of industrial equipment, combined with machine learning algorithms, may significantly improve maintenance activities on modern cyber-physical production systems. However, data of proper quality and of adequate quantity, modeling both good operational conditions as well as abnormal situations throughout the operational lifecycle, are required. Nevertheless, this is difficult to acquire in a non-destructive approach.

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Single atom catalysts receive considerable attention due to reducing noble metal utilization and potentially eliminating certain side reactions. Yet, the rational design of highly reactive and stable single atom catalysts is hampered by the current lack of fundamental insights at the single atom limit. Here, density functional theory calculations are performed for a prototype reaction, namely CO oxidation, over different single metal atoms supported on alumina.

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Alloyed metal nanocatalysts are of environmental and economic importance in a plethora of chemical technologies. During the catalyst lifetime, supported alloy nanoparticles undergo dynamic changes which are well-recognized but still poorly understood. High-temperature O -H redox cycling was applied to mimic the lifetime changes in model Pt In nanocatalysts, while monitoring the induced changes by in situ quick X-ray absorption spectroscopy with one-second resolution.

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Ethanol dehydration to ethene is mechanistically decoupled from the production of higher hydrocarbons due to complete surface coverage by adsorbed ethanol and diethyl ether (DEE). The production of C3+ hydrocarbons was found to be unaffected by water present in the reaction mixture. Three routes for the production of C3+ hydrocarbons are identified: the dimerization of ethene to butene and two routes involving two different types of surface species categorized as aliphatic and aromatic.

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Aim: To present the current treatment approach for oroantral fistula causing maxillary sinusitis.

Design: Case series. Four cases of oroantral fistula (diameters: 6, 9, 11 and 13 mm) due to chronic maxillary sinusitis were treated by excision of all diseased oroantral fistula tissue, followed by endoscopic creation of a large middle antrostomy and closure of the fistula using buccal flaps.

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Angioedema due to use of angiotensin-converting enzyme inhibitors (ACEIs) is a rare side-effect but is seen more often because of the increase in the use of these drugs due to their effectiveness and good tolerance in the treatment of hypertension and congestive heart failure. Other types of angioedema, which should be included in the differential diagnosis, are the hereditary type, which results from deficiency of C1 esterase inhibitor and the allergic angioedema. Angioedema is a potentially life-threatening condition when it is located to the mucosal and submucosal layers of the upper airway.

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The identification of the thrombin receptor has promoted the interest for the development of new therapeutic agents capable of selectively inhibiting unwanted biological effects of thrombin on various cell types. In this study we have designed and synthesized two series of new thrombin receptor antagonists based on the thrombin receptor motif sequence S42FLLR46, one possessing two (Phe/Arg) pharmacophoric groups and the other possessing three (Phe/Arg/NH2). N-(6-Guanidohexanoyl)-N'-(phenylacetyl)piperazine (1), N-(phenylacetyl)-4-(6-guanidohexanoylamidomethyl)piperidine (2), and N-(phenylacetyl)-3-(6-guanidohexanoylamido)pyrrolidine (3) (group A) carry the two pharmacophoric side chains of Phe and Arg residues incorporated on three different templates (piperazine, 4-aminomethylpiperidine, and 3-aminopyrrolidine).

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The angiogenic action of thrombin has been shown to be mediated by activation of the thrombin receptor. In this report we studied the effects of SFLLR, an agonist of the activated thrombin receptor and thrombin receptor peptide and non peptide antagonists on angiogenesis in the chick chorioallantoic membrane (CAM) system. As antagonists were used the tripeptide FPR and non-peptide 1,4-disubstituted piperazine derivatives.

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The novel cyclic analogues cyclo(Phe-Leu-Leu-Arg-epsilonLys-Dap) (1) and cyclo(D-Phe-Leu-Leu-Arg-epsilonLys-Dap) (2), which differ only in the absolute conformation of Phe, have been designed and synthesized based upon the minimal peptide sequence Phe-Leu-Leu-Arg which has been found to exhibit biological activity for the thrombin receptor. Compound 1, in which all amino acids have the L-configuration, exhibited higher activity in the rat aorta relaxation and rat longitudinal muscle bioassays compared to compound 2, in which the Phe residue is in the D-configuration. This is attributed to the spatial proximity of the Phe and Arg in compound 1 which does not exist in its diastereomeric compound 2, as is depicted from a combination of NMR studies and computational analysis.

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Analogues of sarilesin (type I AT1 antagonists), and sarmesin (type II AT1 antagonists) with homoserine (hSer) at position 8 were prepared and bioassayed. The presence of a Tyr4-Ile5-His6 bend found in sarmesin but not in sarilesin was identified. The obtained results coupled with conformational analysis studies, using a combination of NMR spectroscopy and computational chemistry, propose important conformational and stereoelectronic properties for agonist and antagonist activity at AT1 receptors.

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Focal thrombus formation and vasoconstriction serve to defend vessels when vascular damage occurs, but may be detrimental when an atherosclerotic plaque is disrupted. Recently, the identification of the platelet thrombin receptor opened a new area in the development of agents that may selectively inhibit the effects of thrombin on cells, without affecting fibrin formation. In this regard, we have synthesized a number of 1,4-disubstituted piperazines which are designed to be analogues of thrombin receptor activating peptides (TRAP) and carry the pharmacophoric features of Phe and Arg residues present in the active pentapeptide SFLLR.

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Fat emulsions, Intralipid 30% and Intralipid 10% were compared in terms of the resulting plasma levels of different lipid components and clinical tolerance in critically-ill patients with multi-injuries. Sixteen critically-ill patients with severe systemic inflammatory response were randomly assigned to two groups, each one comprised of eight patients. Each group was administered the same quantity of fat/Kg/day either Intralipid 30% or Intralipid 10%.

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Purpose: To investigate the activity of docetaxel and granulocyte colony-stimulating factor support (G-CSF) in patients with advanced non-small-cell lung cancer (NSCLC) previously treated with cisplatin.

Patients And Methods: A total of 60 patients with locoregional and metastatic NSCLC who had relapsed or progressed after first-line treatment with cisplatin-based regimens were enrolled into the trial. Docetaxel at 100 mg/m2 was given as a 1-h infusion with G-CSF (rhG-CSF given s.

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Thrombin, the most potent physiological platelet agonist interacts with cells through a specific G protein-coupled receptor which has been cloned and sequenced. Synthetic thrombin receptor peptides (TRAPs) comprising the first 5 amino acids (SFLLR and SFLLR-NH2) of the new N-terminus tethered ligand of the thrombin receptor that is generated by thrombin's proteolytic activity were found to cause full platelet aggregation. During the screening of novel thrombin receptor derived non-peptide mimetics in the platelet aggregation assay we found that 1-phenylacetyl-4-(6-guanidohexanoyl)-piperazine (1) and 1-(6-guanidohexanoyl)-4-(phenylacetylamidomethyl)-piperidine (2) exerted in vitro antagonist activities (56% and 40% correspondingly) as it is depicted by the platelet aggregation assay.

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Experimental allergic encephalomyelitis (EAE) is induced in susceptible animals by immunodominant determinants of myelin basic protein (MBP). Analogs of these disease-associated peptides have been identified with disease progression upon coimmunization. Usage of peptides, with disease-specific immunomodulatory capacity in vivo is limited, however, due to their sensitivity to proteolytic enzymes.

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The conformational properties of the pentapeptide Ser-Phe-Leu-Leu-Arg (P5), a human thrombin receptor-derived sequence forming part of a tethered ligand which activates the thrombin receptor, and its more active amide derivative Ser-Phe-Leu-Leu-Arg-NH2 (P5-NH2), have been studied by proton NMR spectroscopy in dimethylsulfoxide. Measurements of nuclear Overhauser effects, performed using two-dimensional rotating frame nuclear Overhauser (ROESY) and one-dimensional nuclear Overhauser enhancement (NOE) spectroscopy, revealed that P5 exists mainly in an extended conformation. However, proton-proton 1D-NOEs between Phe C alpha H and Ser C alpha H Leu3 C alpha H and Leu3 NH, and Leu4 C alpha H and Leu4 NH, as well as between the Ser and Arg sidechains, also implicated a minor conformer for P5 having a curved backbone and a near-cyclic structure.

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Anesthetic agents may impair host defense mechanisms including polymorphonuclear leukocyte (PMNL) function. We have studied the effects of thiopentone and propofol in low (thiopentone 10 mg/L, propofol 2 mg/l) and high (thiopentone 40 mg/L, propofol 6 mg/L) clinically relevant concentrations on PMNL adherence, chemotaxis, phagocytosis and killing in vitro. The results demonstrated that thiopentone in both concentrations significantly decreases all PMNL functions tested and had a direct influence on the PMNLs in terms of their chemotactic response.

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