Sinop University

Two novel mononuclear copper(II) complexes, [Cu(H4N9-mpz)]Cl2·H2O (1) and [Cu(H4N9-mpz)](ClO4)2·2CH3OH (2), were synthesized for the first time utilizing the pyrazine-modulated long-chain pentapyridyltetraamine ligand, N2,N2′-(pyrazine-2,6-diyl)bis(N6-(pyridin-2-yl)pyridine-2,6-diamine) (H4N9-mpz). Both complexes were structurally characterized, and their in vitro cytotoxic activities were systematically evaluated. In each compound, the Cu(II) center is five-coordinate, adopting a slightly distorted trigonal bipyramidal geometry, with Addison distortion parameter τ values of 0.84 for complex (1) and 0.86 for complex (2). The H4N9-mpz ligand adopts an all-anti conformation, coordinating to the copper center as a pentadentate monohelical ligand. This trigonal bipyramidal coordination environment was further corroborated by electronic spectroscopy and the observation of "inverted-type" electron paramagnetic resonance (EPR) spectra. The cytotoxic effects of the free H4N9-mpz ligand and complexes 1 and 2 were evaluated against the DLD-1 and PC3 cancer cell lines, as well as the L929 healthy cell line, and compared with the reference drug cisplatin. Complex 2 exhibited superior antiproliferative activity compared to 1, yielding significantly lower IC50 values of 6.401 µM in DLD-1 cells and 2.956 µM in PC3 cells. However, toxicity profiles on healthy L929 cells revealed that complex 1 possesses a higher selectivity index than complex 2. Molecular docking simulations revealed distinct, target-dependent interaction profiles; the free ligand exhibited the highest predicted affinity toward Bcl-2, whereas the copper(II) complexes demonstrated more favorable docking scores against HSP90. These findings provide preliminary computational insights into potential ligand–protein interactions, prompting further experimental validation.

Cancer's global prevalence demands novel therapeutic agents with improved efficacy and selectivity. In this study, six azo-containing derivatives featuring trifluoromethyl (& horbar;CF3) groups and a coumarin scaffold were comprehensively examined, five of which were newly synthesized. Their chemical structures were confirmed using FTIR, UV-Vis, and NMR (1H and 13C) spectroscopy. DFT calculations (B3LYP/6-311++G(d,p)) supported the experimental data, showing strong agreement between theoretical and observed spectra. All compounds fulfilled Lipinski's rule of five, according to ADMEt studies; however, compounds 4b and 4c showed the lowest projected toxicity (LD50: 6480 mg/kg). High binding affinities toward cancer-related VEGFR2 protein targets (PDB IDs: 3VO3, 6GQO, 3VHE, and 3WZD) were found via molecular docking. The compound that interacted with 3VHE the most was compound 5a (-11.2 kcal/mol). The 6GQO-4a complex was shown to be the most stable (-120.099 kJ/mol) by MM/PBSA analysis. This finding was confirmed by 100 ns molecular dynamics simulations that showed constant hydrogen bonding and stable RMSD values. These results point to compound 4a as a promising lead molecule for the development of anticancer drugs, which calls for additional in vitro and in vivo research.

This study investigates the gamma-ray interaction mechanisms and radiation-induced damage in selected proteins (casein, lactoferrin, and lysozyme) and fatty acids (caproic acid, capric acid, and docosahexaenoic acid) using Monte Carlo simulations and theoretical code. The gamma-ray interaction parameters were determined using WinXCOM and compared with GEANT4 and FLUKA simulations in the energy range of 0.04 to 2 MeV. In addition, the number and average energy of secondary electrons generated by photon interactions were obtained using the GEANT4 simulation tool. Radiation-induced damage was quantified through displacement per atom (DPA) and total ionizing dose (TID) calculations using the FLUKA code at representative photon energies of 0.08 MeV, 0.5 MeV, and 1 MeV. The results showed strong agreement (<3% deviation) between the theoretical and simulation outputs, validating the reliability of the applied methods. Lactoferrin exhibited the highest mu/rho, mu, and lowest half-value layer values due to its higher density and heavier elemental composition, whereas the fatty acids showed weaker attenuation capability. Secondary electron production was highest in lactoferrin and lowest in the fatty acids. The DPA and TID analyses revealed that fatty acids are more susceptible to displacement damage at lower energies, while proteins exhibited higher structural disturbance at higher photon energies. In short, the findings demonstrate that gamma-ray interaction probability, secondary electron production, and radiation damage strongly depend on molecular density, composition, and photon energy. These results could provide valuable information for radiation effects on biomolecules, with implications for radiobiology, food irradiation, and medical radiation applications.

This study investigates the influence of the Southern Oscillation and North Sea-Caspian Pattern on maximum rainfall intensities in the Black Sea Region of T & uuml;rkiye. Annual maximum rainfall intensity series from 16 meteorological stations were analyzed, and correlation coefficients were calculated and evaluated at . = 0.01, 0.05, and 0.10 significance levels. Results indicate that the Southern Oscillation predominantly affects short-and medium-duration rainfall in Sinop, whereas the North Sea-Caspian Pattern shows significant correlations with medium-and long-duration rainfall in Bart & Otilde;n, Bayburt, and G & uuml;m & uuml;& uacute;hane. These findings highlight the spatially varying influence of atmospheric oscillations on rainfall extremes in the region.

PurposeThe main objective of this study is to systematically review the existing literature focusing on facial expression recognition (FER) technologies used in tourism destinations.Design/methodology/approachThe document analysis technique, a qualitative research method, was used. A total of 60 studies were identified from the "Scopus" database. The studies were analyzed in terms of publication year and citation count, research method, data collection tools, research title, type of experiment, measurement instrument and technique, research objective, geographical scope, keywords, ethical considerations, research results and research proposal. MAXQDA program was used for the coding phase.FindingsThe findings reveal that destination-focused FER research has increased significantly, particularly over the past two years, and that qualitative and mixed research methods have been used less frequently. Furthermore, it has been determined that the studies largely used a combination of survey and experimental data collection tools. It has been also found that the research titles were oriented toward destination marketing, that the studies were generally conducted in laboratory settings, and that eye-tracking was the most frequently used measurement instrument. In addition, the objectives of the studies focused on the effects of visual stimuli, and China emerged as the leading destination in destination-focused FER research. Finally, it was revealed that ethical issues were not addressed and recommendations were not provided in a significant proportion of the studies, and that the results mainly focused on how visual attention could be enhanced.Research limitations/implicationsWhile this study provides a comprehensive framework for understanding the current position of facial emotion recognition (FER) technologies in the tourism literature within a destination context, it also has some limitations. Firstly, the study only examined publications in the Scopus database, limiting the coverage of the entire literature. Although Scopus is a strong resource due to its inclusion of high-impact, internationally recognized journals, the exclusion of studies from other databases such as Web of Science or Google Scholar may have resulted in the failure to analyze some current or interdisciplinary contributions.Practical implicationsBy examining studies related to FER technology in the context of destinations, it is thought that this study will contribute to the relevant literature by presenting the methodological preferences, application areas, measurement and techniques used, research objectives, ethical dimensions, contributions of the results to the literature, and recommendations presented in a comprehensive framework.Social implicationsThe findings offer valuable insights into the role of FER in emotion-focused destination management and highlight existing gaps and opportunities for future research at the intersection of tourism, technology, and emotional science.Originality/valueThe unique value of this study lies in its systematic, multidimensional, and critical by examining of the destination-focused FER literature, revealing ethical and methodological shortcomings and offering clear directions for future studies.