Publications by authors named "Bayrak R"

Cerebrovascular reactivity (CVR), the ability of cerebral blood vessels to dilate or constrict in order to regulate blood flow, is a clinically useful measure of cerebrovascular health. CVR is often measured using a breath-hold task to modulate blood CO levels during an fMRI scan. Measuring end-tidal CO (PCO) with a nasal cannula during the task allows CVR amplitude to be calculated in standard units (vascular response per unit change in CO, or %BOLD/mmHg) and CVR delay to be calculated in seconds.

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Vigilance is a continuously altering state of cortical activation that influences cognition and behavior and is disrupted in multiple brain pathologies. Neuromodulatory nuclei in the brainstem and basal forebrain are implicated in arousal regulation and are key drivers of widespread neuronal activity and communication. However, it is unclear how their large-scale brain network architecture changes across dynamic variations in vigilance state (i.

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Insufficient sleep can lead to problems. We examined the sociodemographic characteristics, sleep habits, and association between sleep problems. Parents were requested to fill out a survey and Children's Sleep Habits Questionnaire (CSHQ).

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Purpose: This study was conducted to determine the level of knowledge of healthcare professionals involved in newborn heel prick tests.

Methods: The study was conducted between 10.02.

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Machine learning provides a valuable tool for analyzing high-dimensional functional neuroimaging data, and is proving effective in predicting various neurological conditions, psychiatric disorders, and cognitive patterns. In functional magnetic resonance imaging (MRI) research, interactions between brain regions are commonly modeled using graph-based representations. The potency of graph machine learning methods has been established across myriad domains, marking a transformative step in data interpretation and predictive modeling.

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Reproducible identification of white matter pathways across subjects is essential for the study of structural connectivity of the human brain. One of the key challenges is anatomical differences between subjects and human rater subjectivity in labeling. Labeling white matter regions of interest presents many challenges due to the need to integrate both local and global information.

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White matter bundle segmentation using diffusion MRI fiber tractography has become the method of choice to identify white matter fiber pathways in vivo in human brains. However, like other analyses of complex data, there is considerable variability in segmentation protocols and techniques. This can result in different reconstructions of the same intended white matter pathways, which directly affects tractography results, quantification, and interpretation.

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Functional MRI signals can be heavily influenced by systemic physiological processes in addition to local neural activity. For example, widespread hemodynamic fluctuations across the brain have been found to correlate with natural, low-frequency variations in the depth and rate of breathing over time. Acquiring peripheral measures of respiration during fMRI scanning not only allows for modeling such effects in fMRI analysis, but also provides valuable information for interrogating brain-body physiology.

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Histological analysis is typically the gold standard for validating measures of tissue microstructure derived from magnetic resonance imaging (MRI) contrasts. However, most histological investigations are inherently 2-dimensional (2D), due to increased field-of-view, higher in-plane resolutions, ease of acquisition, decreased costs, and a large number of available contrasts compared to 3-dimensional (3D) analysis. Because of this, it would be of great interest to be able to learn the 3D tissue microstructure from 2D histology.

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Diffusion weighted magnetic resonance imaging (DW-MRI) is interpreted as a quantitative method that is sensitive to tissue microarchitecture at a millimeter scale. However, the sensitization is dependent on acquisition sequences (e.g.

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Diffusion weighted MRI (DW-MRI) depends on accurate quantification signal intensities that reflect directional apparent diffusion coefficients (ADC). Signal drift and fluctuations during imaging can cause systematic non-linearities that manifest as ADC changes if not corrected. Here, we present a case study on a large longitudinal dataset of typical diffusion tensor imaging.

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The aim of this study was to examine the role of attachment style, self-concept, and coping strategies, in order to explain the differences in perceived stress factors and stress symptoms, in a mediation model. Participants were 515 university students (302 female and 213 male) aged 17-28 years. The assessment instruments were: Social Comparison Scale, Ways of Coping Scale, Experiences in Close Relationships Scale-II, Brief Symptom Inventory and University Students Stress Factors Scale.

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Diffusion weighted MRI (DWMRI) and the myriad of analysis approaches (from tensors to spherical harmonics and brain tractography to body multi-compartment models) depend on accurate quantification of the apparent diffusion coefficient (ADC). Signal drift during imaging (e.g.

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Photodynamic therapy is one of the hot topics in cancer studies. Photosensitizing chemical substrates are stimulated by light having a specific wavelength to cause fatal effect on different kinds of targets. In this study, axially 4-{[(1E)-2-furylmethylene]amino}phenol, 4-{[(1E)-2-thienylmethylene]amino}phenol and 4-{[(1E)-(4-nitro-2-thienyl)methylene]amino}phenol disubstituted silicon phthalocyanines were synthesized as Photosensitizers for photodynamic therapy in cancer treatment.

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New phthalonitrile compound with Schiff base, carbothioamide and thiazole moieties as substituents and its corresponding metal-free and metallophthalocyanines (Zn(II), Ni(II), Co(II), and Cu(II)) were synthesized and characterized for the first time. The solubilities of these novel phthalocyanines were high in organic solvents. The redox properties of the compounds have been researched by cyclic voltammetry, square wave voltammetry, controlled-potential coulometry and in situ spectroelectrochemistry in dimethylsulfoxide.

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Introduction: To investigate whether there was a protective effect of melatonin on apoptotic mechanisms after an acute unilateral obstruction of the kidney.

Material And Methods: A total of 25 rats consisting of five groups were used in the study, designated as follows: Group 1: control, Group 2: sham, Group 3: unilateral ureteral obstruction treated with only saline, Group 4: unilateral ureteral obstruction treated with melatonin immediately, and Group 5: unilateral obstruction treated with melatonin one day after obstruction. Melatonin was administered as a 10 mg/kg dose intraperitoneally.

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4-Thiadiazole substituted phthalonitrile and peripherally tetra-substituted phthalocyanine Cu(II), Fe(II) and Ti(IV)O complexes have been synthesized for the first time. Electrochemical properties of these complexes were determined with voltammetric and in situ spectroelectrochemical measurements. CuPc has redox inactive Cu(2+) center, therefore it gave three Pc based reduction and two Pc based oxidation processes.

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In this study, novel phthalonitrile derivative (3) was synthesized by the reaction between 4-nitrophthalonitrile (2) and a triazole derivative (1) containing pyridine moiety. Crystal structure of compound (3) was characterized by X-ray diffraction. New metal free and metallo-phthalocyanine complexes (Zn, Cu, and Mg) were synthesized using the phthalonitrile derivative (3).

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Unlabelled: Primary effusion lymphoma (PEL) is a rare type of non-Hodgkin lymphoma that presents with serosal effusion in body cavities, without obvious tumor masses. Although PEL occurs in immunocompromised patients that are human immunodeficiency virus (HIV) positive, it also occurs in immunocompetent human herpes virus-8 (HHV-8)-positive patients. Herein we present an immunocompetent, HIV-negative, CD-20-negative, HHV-8-positive patient with pleural effusion that was diagnosed as PEL.

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In this paper, computational studies were carried out on anastrozole and letrozole, chemotherapy drugs used against breast cancer. Optimization and frequency calculations were performed at B3LYP/6-31G (d) basis set and vibrational frequencies were assignment. Single point calculations were performed at DFT method with a hybrid functional B3LYP/6-311G (d, p) basis set.

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The molecular structure of the substituted phthalonitrile was analyzed crystallographically and compared with optimized geometric structure. The structural properties of the compound such as energy, vibrational frequency, ground state transitions, (1)H and (13)C NMR chemical shifts, NBO analysis and hyperpolarizability were computed by DFT (Density Functional Theory) method and compared with experimental results. The novel Mg(II) and Sn(II) phthalocyanines synthesized from the substituted phthalonitrile and their aggregation behaviors were investigated in different solvents and at different concentrations in DMSO.

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Pregnancy-like (pseudolactational) hyperplasia (PLH) is an uncommon lactational change occurring independently from pregnancy and lactation. PLH has been incidentally found during breast biopsies. We report two different cases of PLH with their clinical, radiologic, and pathologic findings.

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