Publications by authors named "Erol Yildirim"

This work describes one-step syntheses of various stereogenic-at-boron fluorochromes (BOSPYR) multicomponent reactions involving readily accessible boronic acids, salicylaldehydes, and 2-formylpyrrole hydrazones. The dyes absorb and emit in the visible region of the electromagnetic radiation, and are characterized by large Stokes shifts (2850-4930 cm) with weak fluorescence emissions (: 1.5-9.

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Protecting the material surfaces from deposits and insoluble sludge particles extends the engine life and reduces waste. Lubricant detergents in engine oils are essential additive technologies that prevent deposit formation in internal combustion engines. In this study, the effect of sulfonate detergent on deposit formation in a passenger car engine is investigated with experimental and multiscale molecular modeling methods to present a unified approach.

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The performance provided by graphene (Gr) and graphene oxide (GO) additives can be improved by achieving strong adhesion and uniform dispersion in the epoxy resin matrix. In this study, molecular modeling and simulation of DGEBA/DETA based epoxy nanocomposites containing Gr and GO additives were performed. Density functional theory and molecular dynamics simulations were used to investigate interfacial interaction energies and Young's Modulus.

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In this study, six different donor-π-acceptor-π-donor-acceptor type random co-polymers containing benzodithiophene as a donor, benzooxadiazole (BO), and thieno[3,4-c]pyrrole-4,6-dione (TPD) as acceptor, have been synthesized and characterized. In addition to the acceptor core ratio at different values, the effect of aromatic bridge structures on the optical, electronic, and photovoltaic properties of six different random co-polymers is investigated by using thiophene and selenophene structures as aromatic bridge units. To investigate how the acceptor unit ratio and replacement of aromatic bridge units impact the structural, electronic, and optical properties of the polymers, density functional theory (DFT) calculations are carried out for the tetramer models.

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Introduction: Emotion recognition, the ability to interpret the emotional state of individuals by looking at their facial expressions, is essential for healthy social interactions and communication. There is limited research on the effects of tDCS on emotion recognition in the literature. This study aimed to investigate the effects of anodal stimulation of the ventromedial prefrontal cortex (vmPFC), a key region for emotion recognition from facial expressions, on emotion recognition and brain oscillations.

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Cationic perylenediimide derivative, namely N,N'-di(2-(trimethylammoniumiodide)ethylene) perylenediimide (TAIPDI), has been synthesized and characterized in an aqueous medium by using dynamic light scattering (DLS), X-ray diffraction (XRD), fourier-transform infrared (FTIR), scanning electron microscope (SEM), and high-resolution transmission electron microscopy (HRTEM) techniques. The optical absorption and fluorescence spectra of TAIPDI revealed the formation of aggregated TAIPDI nanowires in water, but not in organic solvents. In order to control the aggregation behavior, the optical properties of TAIPDI have been examined in different aqueous media, namely cetyltrimethylammonium bromide (CTAB), and sodium dodecyl sulfate (SDS).

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Depression is a complex disorder that can be caused by psychosocial and biological conditions, and it not only affects to emotional life, but also cognitive functions, specifically the executive functions, attention, psychomotor speed, and memory. Some results of the studies in the literature show that depressed individuals perform worse on cognitive tasks than healthy individuals, while others indicate that there is no difference. Moreover, there is also no consensus about the depressed people brain functionalities.

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Common polymers can accumulate surface charges through contact, a phenomenon known since ancient times. This charge accumulation can have detrimental consequences in industry. It causes accidents and yields enormous economic losses.

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More than 50 different acceptor units from the experimental literature have been modeled, analyzed, and compared by using the computationally extracted data from the density functional theory (DFT) perspective for tetramer structures in the form of (D-B-A-B) (D, donor; A, acceptor; B, bridge) with fixed donor and bridge units. Comparison of dihedral angle between acceptor, donor, and bridge units, bond order, and hyperpolarizability reveals that these three structural properties have a dominant effect on the frontier electronic energy levels of the acceptor units. Systematic investigation of the structural properties has demonstrated the band gap energy dependency of the acceptor units on the planarity, conjugation, and the electron delocalization.

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Squaramide/cinchona alkaloid-derived bifunctional organocatalysts are in high demand in asymmetric transformations. Bifunctional quinine-derived sterically encumbered squaramide (H-bond donor) organocatalysts were used to catalyze the asymmetric Friedel-Crafts/S2 type domino reaction of ()-α-bromonitroalkenes and α/β-naphthols and phenol derivatives to generate enantiomerically enriched dihydronaphthofuran (DHN) and dihydrobenzofuran (DHB) derivatives, respectively. The target adducts were obtained in up to >99% ee under mild conditions with a relatively low catalyst loading (5 mol%) compared to the methods known in the literature.

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Objective: The aim of the study is to verify the impact of anxiety on temporomandibular disorders (TMD) by using specific questionnaires in a Turkish sample.

Methods: This survey was conducted on 292 patients with a mean age of 38.59 ± 10.

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Polylactic acid (PLA) is a widely used bioresorbable polymer in medical devices owing to its biocompatibility, bioresorbability, and biodegradability. It is also considered a sustainable solution for a wide variety of other applications, including packaging. Because of its widespread use, there have been many studies evaluating this polymer.

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Self-assembling bio-instructive materials that can provide a biomimetic tissue microenvironment with the capability to regulate cellular behaviors represent an attractive platform in regenerative medicine. Herein, we develop a hybrid neuro-instructive hydrogel that combines the properties of a photo-crosslinkable gelatin methacrylate (GelMA) and self-assembling peptide amphiphiles (PAs) bearing a laminin-derived neuro-inductive epitope (PA-GSR). Electrostatic interaction and ultraviolet light crosslinking mechanisms were combined to create dual-crosslinked hybrid hydrogels with tunable stiffness.

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To understand the properties of polyaniline (PANI), aim gas, and the interaction between them in PANI-based gas sensors and help us to design sensors with better properties, direct calculations with molecular dynamics (MD) simulations were done in this work. Polyamide 6/polyaniline (PA6/PANI) nanofiber ammonia gas sensors were studied as an example here, and the structural, morphological, and ammonia sensing properties (to 50-250 ppm ammonia) of PA6/PANI nanofibers were tested and evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy, and a homemade test system. The PA6/PANI nanofibers were prepared by in situ polymerization of aniline with electrospun PA6 nanofibers as templates and hydrochloric acid (HCl) as a doping agent for PANI, and the sensors show rapid response, ideal selectivity, and acceptable repeatability.

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The first checklist of Sphecidae of Tunisia is established. It is based on literature, on examination of Tunisian specimens present in the Muséum National d'Histoire Naturelle, Paris, France), and on specimens recently collected in Tunisia. Fifty-three species and subspecies belonging to 10 genera, 3 tribes and 4 subfamilies are listed.

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The conceptual understanding of charge transport in conducting polymers is still ambiguous due to a wide range of paracrystallinity (disorder). Here, we advance this understanding by presenting the relationship between transport, electronic density of states and scattering parameter in conducting polymers. We show that the tail of the density of states possesses a Gaussian form confirmed by two-dimensional tight-binding model supported by Density Functional Theory and Molecular Dynamics simulations.

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The goal of this work is to provide physical insights into the formation and stability of inclusion complexes (ICs) in aqueous solution between cyclodextrins (CDs) and a common flame retardant, triphenyl phosphate (TPP). Quantum chemistry calculations reveal the possible energetically favorable geometries of TPP in their 1:1 IC form with α-, β-, and γ-CDs as well as their associated complexation, conformational, and interaction energies. High-resolution mass spectrometry (MS) and tandem MS were used with electrospray ionization to study the soluble ICs formed between TPP and CDs.

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Article Synopsis
  • Dimethylsulfone (DMSO) enhances the alignment and crystallization of PEDOT:PSS, significantly improving its electrical conductivity.
  • The use of DMSO as a dopant leads to a remarkable conductivity of up to 1080 S/cm in the PEDOT:PSS film while maintaining stability over 60 days of humidity exposure.
  • Advanced calculations on pairwise interaction energies helped clarify how DMSO boosts the electrical properties, presenting it as a greener alternative to traditional dopants like dimethyl sulfoxide and ethylene glycol.
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Hybrid (organic-inorganic) materials have emerged as a promising class of thermoelectric materials, achieving power factors (Sσ) exceeding those of either constituent. The mechanism of this enhancement is still under debate, and pinpointing the underlying physics has proven difficult. In this work, we combine transport measurements with theoretical simulations and first principles calculations on a prototypical PEDOT:PSS-Te(Cu) nanowire hybrid material system to understand the effect of templating and charge redistribution on the thermoelectric performance.

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Introduction: Patients with obsessive compulsive disorder (OCD) have impaired cognitive functions, including attention, verbal and visual memory, and visual-spatial abilities as well as executive function But some studies did not show any disturbance in executive function of patients with OCD. To date, only few studies have been conducted on neuropsychological functioning of patients with panic disorder (PD). There are limited studies to reach a definite conclusion on executive functions of patients with OCD and those with PD.

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Nanocomposites prepared by incorporating functionalized polyhedral oligomeric silsesquioxane (POSS) into polymer matrices afford a wide range of versatile hybrid materials for use in technologies ranging from cosmetics and pharmaceuticals to sensors and batteries. Here, we investigate the phase behavior of nanocomposites composed of poly(ethylene oxide) (PEO) and monosubstituted isobutyl POSS (iPOSS) modified with different functional moieties. Microscopic analyses of blends containing these iPOSS variants reveal the existence of different macroscopic morphologies and surface topologies.

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In this study, we report the synthesis of a novel heteroleptic Ru(ii)-sensitizer, (Ru(2,2'-bipyridine-4,4'-dicarboxylic acid)-4,4'-bis(4-piperidin-1-yl)phenyl ethenyl)-(2,2'-bipyridine) (NCS), denoted as SD-1; moreover, its photophysical, electrochemical, and photovoltaic performances were compared with those of N719 and K77-7 (N,N'-diaryl Ru-sensitizer, namely Ru(2,2'-bipyridine-4,4'-dicarboxylic-acid)-4,4'-bis(2-(4-N,N'-diphenylaminophenyl)ethenyl)-2,2'-bipyridine (NCS)). The photovoltaic performance of SD-1 outperformed those of N-719 and K77-7, particularly in the red region, and the overall efficiency of SD-1 was 8.5% as compared to 8.

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Background: Neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) give information about many diseases. An increase in inflammation markers occurs in patients with obstructive sleep apnea syndrome (OSAS).

Objectives: The aim of this study is to determine the relationship between OSAS and NLR and PLR values.

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Hydrated polyelectrolyte (PE) complexes and multilayers undergo a well-defined thermal transition that bears resemblance to a glass transition. By combining molecular simulations and differential scanning calorimetry (DSC) of poly(diallyldimethylammonium) (PDAC) and poly(styrenesulfonate) (PSS) multilayers, we establish for the first time that dehydration drives the thermally induced change in plasticization of the complex and in the diffusion behavior of its components. DSC experiments show that the thermal transition appears when the assemblies are hydrated in water but not in the presence of alcohols, which supports that water is required for this transition.

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