Erkan Aksoy

Heavy atom insertions are often used to increase spin–orbit coupling to enhance the performance of advanced emissive molecules. In this work we apply heavy atoms in both the linker (thiophene) and donor (phenoselenazine) groups of D-A emitters, and compare these to triazine-based reference emitters that show thermally activated delayed fluorescence (TADF). While the thiophene groups provide a lower-energy triplet state suitable for room temperature phosphorescence (RTP), the additional inclusion of Se allows the corresponding PSe-ThZ material to undergo RTP even in solution (sRTP). Despite having similar separation of singlet and triplet energies, much weaker sRTP activity in a phenoxazine-substituted emitter without the Se atom shows the utility of this approach, but also that inclusion of cooperative heavy atoms can detract from TADF performance.

Metal‐free g‐C₃N₄ (graphitic carbon nitride) is a promising candidate for the next‐generation visible light‐responsive photocatalyst; however, the recombination and transfer of the photogenerated charge carriers restrict its photocatalytic performances. The exfoliated g‐C₃N₄ sensitized with brominated perylenediimide (dBrPDI) and perylene tetraester (dBrPTE) enhances the photocatalytic performance due to improved charge separation, light absorption, charge transfer and, thereby, overall efficiency in pollutant degradation. The g‐C₃N₄/dBrPTE hybrid composite exhibits the fastest photocatalytic degradation against rhodamine B (RhB) pollutants. The g‐C₃N₄/dBrPTE hybrid composite degrades RhB with a 2.34‐fold improvement over pure g‐C₃N₄, while the g‐C₃N₄/dBrPDI hybrid composite degrades with a 1.56‐fold increase over pure g‐C₃N₄. The g‐C3N4/dBrPDI hybrid composite shows the highest photocatalytic efficiency against methyl orange (MO) pollutants. The g‐C₃N₄/dBrPDI hybrid composite degrades MO with a 2.25‐fold improvement over pure g‐C₃N₄, while the g‐C₃N₄/dBrPTE hybrid composite degrades with a 1.8‐fold increase over pure g‐C₃N₄. Unlike MO and RhB, the perylene dye sensitization does not enhance the photocatalytic degradation of 2,4‐dichloro phenoxy acetic acid (2,4‐D) and no sustained increase in efficiency is not observed. Overall, these results suggest that photocatalytic efficiency depends not only on the sensitized photocatalyst material but also on the interaction between the sensitized photocatalyst and the chemical and ionic properties of the pollutants in the aquatic media.

Reusing waste or otherwise discarded polymethyl methacrylate (wPMMA) as a host matrix for optical photonic applications such as down-conversion or luminescence solar concentrators can spare the use of pristine materials, with strong implications for sustainability. Here, a homogeneous emissive film was produced using wPMMA by dissolving in toluene and adding a fluorescent perylene dye (perylene-3,4,9,10-tetracarboxylic hexyl ester, PTHE) followed by spin coating casting. This resulting film is optically transparent and green-emissive with a high photoluminescence quantum yield (PLQY of 84%). It has been investigated by various spectroscopic techniques such as absorption, photoluminescence, emission lifetime, and dye photostability. While this film exhibited some excimer PL at longer wavelengths compared to the solution phase, it also increased its emission lifetime by approximately 3 times. Moreover, while the CIE coordinates (x, y) of the blue-green PL in the solution phase was 0.21, 0.56, the PL spectrum of the wPMMA:PTHE film instead had (CIE, x, y) of 0.30, 0.60. Recycling these and similar suitable waste polymers and transforming them into value-added products such as down-conversion or luminescent solar concentrator films can contribute to sustainable development goals within the scope of clean energy, energy efficiency, and waste utilization.

Aim: Colorectal cancer is the leading cause of cancer-related mortality. Metabolic syndrome is associated with obesity, pre-diabetes, and dyslipidemia. The purpose of the study was to investigate the effects of TyG Index as a novel biomarker on CRC risk. Material and Method: The study was conducted with 256 people in total, including the CRC (n=124) and Control Groups (n=132). TyG Index was calculated by using fasting triglycerides and glucose with the formula Ln [fasting TGs (mg/dL) x fasting glucose (mg/dL)/2]. The performance of the TyG Index to predict the presence of CRC was also evaluated. Results: Metabolic parameters associated with insulin resistance were found to be at statistically significant levels in the CRC Group. Fasting plasma glucose, triglyceride, insulin, hemoglobin A1c, and GGT were also statistically significant. It was also determined that the cut-off value of the TyG Index for the presence of CRC was 4.49 (AUC = 0.782, sensitivity 77%, specificity = 78.4%, and p=0.002). Conclusion: In the present study, it was found that the TyG Index is associated with the risk of CRC and can be used as a novel biomarker in high-risk CRC cases.

Polylactide (PLA) is a biodegradable polymer derived from natural resources used in various applications ranging from medical to packaging. In this study, biocomposites were developed by combining perlite mineral (PER), a natural filler material, with a biodegradable PLA matrix in incorporated contaminations of 2.5%, 5%, 10%, and 15%. The purpose of this work is to obtain composites having low production costs while retaining their main properties. Mixing force measurements, tensile, Shore hardness, impact tests, melt flow indices (MFI), and scanning electron microscopy (SEM) evaluations were carried out on composite samples to determine the processing, mechanical, melt flow, and morphological aspects of the developed composites. When the tensile test data were reviewed, minor decreases in the tensile strength and % elongation parameters were noticed with perlite loadings. The inclusion of perlite powder significantly reduced the impact strength value of PLA. Composites with high amounts of PER displayed elevated hardness values. While the MFI results were analyzed, it was deduced that the addition of PER increased the melt flow characteristics of the PLA polymer. At low PER quantities, SEM micrographs displayed that PER particles were homogeneously distributed in the PLA phase. The particle homogeneity in the composite morphology deteriorated as the PER loading ratio in the composites rose. According to the overall results, the highest performance among composites was achieved in the sample including 2.5% PER, and this sample was considered to be the most suitable option for applications regarding PLA-based biocomposite material purposes.

Aim: Obesity is strongly associated with increased risk of many cancer types. It is estimated that approximately 20% of all cancers are caused by overweight. It is considered that there is a direct relation between overweight and thyroid cancer. The aim of this study is to evaluate the incidence and clinicopathological distribution of thyroid cancer in bariatric surgery cases. Materials and Methods: The present study was conducted with a total of 2316 patients who underwent bariatric surgery because of morbid obesity in our metabolic and bariatric surgery clinic between April 2014 and November 2021. Results: It was found that the prevalence of thyroid cancer was 1.2% in morbidly obese cases. A total of 23 patients had papillary thyroid cancer (0.99%), 3 patients had follicular cancer (0.12%), 1 patient had medullary cancer (0.04%), and 1 patient had anaplastic cancer (0.04%). Conclusion: It was found in the present study that the most common cancer type was thyroid papillary cancer, and follicular, medullary, and anaplastic cancer were found to be less frequently. There appears to be a relation between Body Mass Index and the thyroid cancer risk.

Solid state optical properties of fluorescent materials are important for many optical and electronic photonic devices such as organic light emitting diodes, frequency down-converters or luminescent solar concentrators. Perylene diimides (PDIs) represent one of the most popular organic semiconductors which find application in those phonic device applications. In this study, photophysical properties of two dibrominated PDI (DiBrPDIs), one of which contains a branched alkyl chain (2-ethylhexyl, 2-EH) and the other has an aromatic substituent (diisopropylphenyl, DIA) at the imide positions are comparatively studied. Besides their absorption and photoluminescence, lifetime and photoluminescence quantum yield (PLQY), photoinduced absorption properties (PIA) were also examined by fs-transient absorption spectroscopy. Due to their the same π conjugated system, DiBrPDI-DIA and DiBrPDI-2EH exhibited identical absorption and photoluminescence (PL) spectra in solution phase (λabs:527 nm and λPL:552 nm). However, in their film phases which were prepared at the same conditions, DiBrPDI-DIA (λPL-DIA:596 nm; PLQY:73.4%) presented a shorter PL wavelength with a higher PLQY than that of DiBrPDI-2EH (λPL-2EH:649 nm; PLQY:36.7%). 3-D investigations performed by using Chem3D pro software addressed the higher intermolecular distance between the perylene rings induced by the bulky DIA groups, as the main reason of this difference.