934 results on '"A, UGUR"'
Search Results
2. Efficacy of the Cardiac Implantable Electronic Device Multisensory Triage-HF Algorithm in Heart Failure Care: A Real-World Clinical Experience.
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Aslan, Ugur, Beeres, Saskia L. M. A., Feijen, Michelle, Mulder, Gerlinde M., Jukema, J. Wouter, and Egorova, Anastasia D.
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ARTIFICIAL implants , *HEART failure , *CLINICAL medicine , *ELECTRONIC equipment , *NURSES as patients , *ALGORITHMS - Abstract
Heart failure (HF) admissions are burdensome, and the mainstay of prevention is the timely detection of impending fluid retention, creating a window for medical treatment intensification. This study evaluated the accuracy and performance of a Triage-HF-guided carepath in real-world ambulatory HF patients in daily clinical practice. In this prospective, observational study, 92 adult HF patients (71 males (78%), with a median age of 69 [IQR 59–75] years) with the Triage-HF algorithm activated in their cardiac implantable electronic devices (CIEDs), were monitored. Following high-risk alerts, an HF nurse contacted patients to identify signs and symptoms of fluid retention. The sensitivity and specificity were 83% and 97%, respectively. The positive predictive value was 89%, and negative predictive value was 94%. The unexplained alert rate was 0.05 alerts/patient year, and the false negative rate was 0.11 alerts/patient year. Ambulatory diuretics were initiated or escalated in 77% of high-risk alert episodes. In 23% (n = 6), admission was ultimately required. The median alert handling time was 2 days. Fifty-eight percent (n = 18) of high-risk alerts were classified as true positives in the first week, followed by 29% in the second–third weeks (n = 9), and 13% (n = 4) in the fourth–sixth weeks. Common sensory triggers included an elevated night ventricular rate (84%), OptiVol (71%), and reduced patient activity (71%). The CIED-based Triage-HF algorithm-driven carepath enables the timely detection of impending fluid retention in a contemporary ambulatory setting, providing an opportunity for clinical action. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Urinary Dickkopf 3 Is Not an Independent Risk Factor in a Cohort of Kidney Transplant Recipients and Living Donors.
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Jehn, Ulrich, Altuner, Ugur, Henkel, Lino, Menke, Amélie Friederike, Strauss, Markus, Pavenstädt, Hermann, and Reuter, Stefan
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KIDNEYS , *KIDNEY transplantation , *KIDNEY physiology , *GLOMERULAR filtration rate , *CHRONIC kidney failure , *GRAFT survival - Abstract
Urinary dickkopf 3 (uDKK3) is a marker released by kidney tubular epithelial cells that is associated with the progression of chronic kidney disease (CKD) and may cause interstitial fibrosis and tubular atrophy. Recent evidence suggests that uDKK3 can also predict the loss of kidney function in CKD patients and kidney transplant recipients, regardless of their current renal function. We conducted a prospective study on 181 kidney transplant (KTx) recipients who underwent allograft biopsy to determine the cause, analyzing the relationship between uDKK3 levels in urine, histological findings, and future allograft function progression. Additionally, we studied 82 living kidney donors before unilateral nephrectomy (Nx), 1–3 days after surgery, and 1 year post-surgery to observe the effects of rapid kidney function loss. In living donors, the uDKK3/creatinine ratio significantly increased 5.3-fold 1–3 days after Nx. However, it decreased significantly to a median level of 620 pg/mg after one year, despite the absence of underlying primary kidney pathology. The estimated glomerular filtration rate (eGFR) decreased by an average of 29.3% to approximately 66.5 (±13.5) mL/min/1.73 m2 after one year, with no further decline in the subsequent years. uDKK3 levels increased in line with eGFR loss after Nx, followed by a decrease as the eGFR partially recovered within the following year. However, uDKK3 did not correlate with the eGFR at the single time points in living donors. In KTx recipients, the uDKK3/creatinine ratio was significantly elevated with a median of 1550 pg/mg compared to healthy individuals or donors after Nx. The mean eGFR in the recipient group was 35.5 mL/min/1.73 m2. The uDKK3/creatinine ratio was statistically associated with the eGFR at biopsy but was not independently associated with the eGFR one year after biopsy or allograft loss. In conclusion, uDKK3 correlates with recent and future kidney function and kidney allograft survival in the renal transplant cohort. Nevertheless, our findings indicate that the uDKK3/creatinine ratio has no prognostic influence on future renal outcome in living donors and kidney recipients beyond the eGFR, independent of the presence of acute renal graft pathology, as correlations are GFR-dependent. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Long‐term headache after spontaneous intracerebral haemorrhage.
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Gurol, Ugur, Scopelliti, Giuseppe, Cordonnier, Charlotte, and Puy, Laurent
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CEREBRAL hemorrhage , *HEADACHE , *INTRACEREBRAL hematoma , *ODDS ratio , *MENTAL depression - Abstract
Background: Though headache is commonly observed after stroke and may affect survivors' quality of life, it has rarely been studied after spontaneous intracerebral haemorrhage (ICH). In a cohort of ICH survivors, we assessed the long‐term prevalence and determinants of headache. Methods: We screened consecutive ICH survivors enrolled in the prospective, single‐centre Prognosis of Intracerebral Haemorrhage study for headache 1, 3, and 6 years after ICH, according to the International Headache Society's criteria. Depressive and anxiety symptoms severity was measured at 1‐year follow‐up. Variables associated with the presence of headache 1 year after ICH were analyzed using univariate and multivariable models. Results: Among the 146 patients included in this study, 31 (21%), 25 (19%), and 14 (20%) patients reported headache at 1‐, 3‐, and 6‐year follow‐up, respectively. In an age‐adjusted model, patients with headache at ICH onset (adjusted odds ratio [aOR] 2.75; 95% CI 1.02–7.42) and previous history of headache (aOR 4.60; 95% CI 1.74–12.1) were associated with headache at 1‐year follow‐up. Patients with headache were more likely to report depressive and anxiety symptoms at 1‐year follow‐up (both p < 0.02). Conclusions: One in five ICH survivors suffered from headache and patients who reported headache at ICH onset were especially at risk. [ABSTRACT FROM AUTHOR]
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- 2024
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5. De-embedding method for a sensing area characterization of planar microstrip sensors without evaluating error networks.
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Hasar, Ugur C., Ozturk, Hamdullah, Korkmaz, Huseyin, Nayyeri, Vahid, and Ramahi, Omar M.
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A de-embedding method for determining all scattering (S-) parameters (e.g., characterization) of a sensing area of planar microstrip sensors (two-port network or line) is proposed using measurements of S-parameters with no calibration. The method requires only (partially known) non-reflecting line and reflecting line standards to accomplish such a characterization. It utilizes uncalibrated S-parameter measurements of a reflecting line, direct and reversed configurations of a non-reflecting line, and direct and reversed configurations of the sensing area. As different from previous similar studies, it performs such a characterization without any sign ambiguity. The method is first validated by extracting the S-parameters of a bianisotropic metamaterial slab, as for a two-port network (line), constructed by split-ring-resonators (SRRs) from waveguide measurements. Then, it is applied for determining the S-parameters of a sensing area of a microstrip sensor involving double SRRs next to a microstrip line. The root-mean-square-error (RMSE) analysis was utilized to analyze the accuracy of our method in comparison with other techniques in the literature. It has been observed from such an analysis that our proposed de-embedding technique has the lowest RMSE values for the extracted S-parameters of the sensing area of the designed sensor in comparison with those of the compared other de-embedding techniques in the literature, and have similar RMSE values in reference to those of the thru-reflect-line calibration technique. For example, while RMSE values of real and imaginary parts of the forward reflection S-parameter of this sensing area are, respectively, around 0.0271 and 0.0279 for our de-embedding method, those of one of the compared de-embedding techniques approach as high as 0.0318 and 0.0324. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Simple and inexpensive microwave setup for industrial based applications: Quantification of flower honey adulteration as a case study.
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Hasar, Ugur C., Hasar, Hafize, Ozturk, Hamdullah, Korkmaz, Huseyin, Kaya, Yunus, Ozkaya, Mehmet Akif, Ebrahimi, Amir, Barroso, Joaquim J., Nayyeri, Vahid, and Ramahi, Omar M.
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ADULTERATIONS , *MEASUREMENT errors , *MICROWAVE measurements , *MICROWAVES , *INDUSTRIAL applications - Abstract
A simple and inexpensive microwave measurement setup based on measurements of magnitudes of transmission properties ( | S 21 | dB ) is proposed for industrial-based microwave aquametry (moisture or water content) applications. An easy-to-apply calibration procedure based on normalization is implemented to eliminate systematic errors in the measurement system. As a case study, we applied this setup for the quantification of water-adulteration in flower honey. After validating this system by distilled water and pure flower honey measurements, | S 21 | dB measurements of the pure flower honey with various adulteration percentages (δ ) up to 9% are conducted to examine the performance of the measurement setup for quantification of water adulteration. A multi-dimensional fitting procedure is implemented to predict δ using the proposed inexpensive microwave measurement setup. It is shown that it is possible to quantify an adulteration level with an accuracy better than ∓ 1 % by the proposed measurement setup and the applied multi-dimensional fitting procedure. [ABSTRACT FROM AUTHOR]
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- 2024
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7. A new method for fully automated detection of algae blooms in Antarctica using Sentinel-2 satellite images.
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Acar, Ugur, Yilmaz, Osman Salih, Balik Sanli, Fusun, and Ozcimen, Didem
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ALGAL blooms , *REMOTE-sensing images , *TOXIC algae , *GLACIAL melting , *CLIMATE change ,ANTARCTIC glaciers - Abstract
The melting of Antarctic glaciers has become a significant issue as a result of global climate change. Algae on the Antarctic ice/snow is an important part of terrestrial photosynthetic organisms. Monitoring and tracking these algal blooms is crucial for understanding the melting of glaciers in the region. Due to the climatic and natural conditions of the region, traveling to and arranging logistics for monitoring and observing snow algae in the Antarctic continent becomes extremely challenging. To overcome these challenges, a novel algorithm has been developed and designed to automatically detect and analyze green algae (Chlorella sp.) from satellite images. Leveraging the vast and free available data from the Sentinel-2 satellite, the algorithm utilizes its high spectral resolution capabilities, capturing invaluable information from various spectral bands. The algorithm was formulated based on the image obtained on February 28, 2017, where green algae formations were intensively seen in the Ryder Bay. The algorithm was developed based on rule-based detection of algae, with the usage of reflection values from the areas where ground truth was established on this date. The developed algorithm was coded and tested using Python version 3.9. The accuracy analysis of the algorithm was conducted using overall accuracy (OA), F1 score, and Kappa statistical test. As a result of the analysis, the OA, F1 score, and Kappa statistic values were calculated as %91, %88.82-%95.27, and 0.901, respectively. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Targeted Sequencing of Human Satellite 2 Repeat Sequences in Plasma cfDNA Reveals Potential Breast Cancer Biomarkers.
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Gezer, Ugur, Oberhofer, Angela, Worf, Karolina, Stoetzer, Oliver, Holdenrieder, Stefan, and Bronkhorst, Abel
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TUMOR markers , *CELL-free DNA , *BREAST cancer , *NUCLEOTIDE sequence , *CANCER patients , *FACIOSCAPULOHUMERAL muscular dystrophy - Abstract
Liquid biopsies are revolutionizing the detection and management of malignant diseases. While repetitive DNA sequences, such as LINE-1 and ALU are established in cell-free DNA (cfDNA) research, their clinical applications remain limited. In this study, we explore human satellite 2 (HSATII), a prevalent repeat DNA sequence in plasma that exhibits increased levels in cancer patients, thereby positioning it as a potential pan-cancer biomarker. We employed targeted sequencing and copy number variation (CNV) analysis using two primer pairs to assess the differential abundance of HSATII sequences in the plasma of breast cancer patients compared to healthy individuals. PCR amplicons of HSATII from 10 patients and 10 control subjects were sequenced, generating 151 bp paired-end reads. By constructing a pooled reference dataset, HSATII copy ratios were estimated in the patients. Our analysis revealed several significant CNVs in HSATII, with certain sequences displaying notable gains and losses across all breast cancer patients, suggesting their potential as biomarkers. However, we observed pronounced fragmentation of cfDNA in cancer, leading to the loss of longer PCR amplicons (>180 bp). While not all observed losses can be attributed to fragmentation artifacts, this phenomenon does introduce complexity in interpreting CNV data. Notably, this research marks the first instance of targeted HSATII sequencing in a liquid biopsy context. Our findings lay the groundwork for developing sequencing-based assays to detect differentially represented HSATII sequences, potentially advancing the field of minimally-invasive cancer screening. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Proton Craniospinal Irradiation with Immunotherapy in Two Patients with Leptomeningeal Disease from Melanoma.
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Sener, Ugur, Webb, Mason, Breen, William G., Neth, Bryan J., Laack, Nadia N., Routman, David, Brown, Paul D., Mahajan, Anita, Frechette, Kelsey, Dudek, Arkadiusz Z., Markovic, Svetomir N., Block, Matthew S., McWilliams, Robert R., Dimou, Anastasios, Kottschade, Lisa A., Montane, Heather N., Kizilbash, Sani H., and Campian, Jian L.
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PROTON therapy , *MENINGEAL cancer , *CANCER treatment , *DISEASE progression , *IMMUNE checkpoint inhibitors - Abstract
Introduction: Proton craniospinal irradiation (pCSI) is a treatment option for leptomeningeal disease (LMD), which permits whole neuroaxis treatment while minimizing toxicity. Despite this, patients inevitably experience progression. Adding systemic therapy to pCSI may improve outcomes. Methods: In this single-institution retrospective case series, we present the feasibility of treatment with pCSI (30Gy, 10 fractions) and an immune checkpoint inhibitor (ICI) in two sequential patients with LMD from melanoma. Results: The first patient developed LMD related to BRAF V600E-mutant melanoma after prior ICI and BRAF-targeted therapy. After pCSI with concurrent nivolumab, the addition of relatlimab, and BRAF-targeted therapy, he remained alive 7 months after LMD diagnosis despite central nervous system progression. The second patient developed LMD related to BRAF-wildtype melanoma after up-front ICI. He received pCSI with concurrent ipilimumab and nivolumab, then nivolumab maintenance. Though therapy was held for ICI hepatitis, the patient remained progression-free 5 months after LMD diagnosis. Conclusion: Adding an ICI to pCSI is feasible for patients with LMD and demonstrates a tolerable toxicity profile. While prospective evaluation is ultimately warranted, pCSI with ICI may confer survival benefits, even after prior ICI. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Effects of intramolecular hydrogen bonding on nuclear magnetic resonance, electron paramagnetic resonance and molecular docking studies: Mexiletine molecule.
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Tasdemir, Halil Ugur
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ELECTRON paramagnetic resonance , *NUCLEAR magnetic resonance , *CHEMICAL shift (Nuclear magnetic resonance) , *MOLECULAR docking , *HYDROGEN bonding , *MOLECULAR force constants - Abstract
Context: In this study, the molecular structure of the mexiletine molecule was investigated. Since the Mexiletine molecule is a drug active ingredient, its molecular structure and spectroscopic properties are important. The effects of intramolecular hydrogen bonding on Nuclear Magnetic Resonance Parameters (NMR), Electron Paramagnetic Resonance (EPR) parameters and molecular docking studies were examined in the mexiletine molecule. The effects of intramolecular hydrogen bonding on EPR parameters and molecular docking studies are the most important steps for this study. Method: Conformational space scanning required for molecular structure calculations was carried out with the Molecular Mechanic Force Field method. DFT method with 6–311 + + G(d,p) basis set level was used to obtain the most stable structure among the conformations. NMR parameters (1H and 13C chemical shift values) were also performed using the same basis set as the DFT method. The radicals created to calculate the Electron Paramagnetic Resonance parameters were modeled using the DFT/B3LYP/6–311 + + G(d,p) method basis set level. Molecular Docking studies were carried out with the Autodock vina program. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Investigation of the Correlation Between the Visually Induced Motion Sickness Susceptibility Questionnaire and the Turkish Motion Sickness Susceptibility Questionnaire.
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Ugur, Emel
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MOTION sickness , *REFERENCE values , *VIRTUAL reality , *QUESTIONNAIRES , *PARTICIPANT observation - Abstract
Background and Objectives: Visually induced motion sickness (VIMS) is a phenomenon similar to motion sickness frequently observed in users of visual technologies. The Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ), developed by Golding et al. (2006), is considered the most effective scale for assessing VIMS susceptibility levels. The main purpose of this study was to standardize the selection of participants for research conducted with virtual reality, especially motion sickness (MS) research. To achieve this, first, the Turkish version of the VIMSSQ was created to establish its validity and reliability, and subsequently, its correlation with the Turkish Motion Sickness Susceptibility Questionnaire Short form (HDDA), the expanded version of the Motion Sickness Susceptibility Questionnaire Short form (MSSQ), was examined. Subjects and Methods: Linguistic equivalence assessment was obtained from ten experts by passing the VIMSSQ through the translation process. The VIMSSQ and the Turkish MSSQ forms were then administered to 49 subjects. This study statistically analyzed the validity and reliability of the VIMSSQ and its relationship with the MSSQ. Results: Results showed that the Turkish version of the original questionnaire is highly reliable (Cronbach alpha=0.843). There is a moderate statistically significant positive correlation between the total MSSQ scores and the subfactors of the VIMSSQ. Conclusions: In this study, VIMSSQ was successfully adapted to Turkish, normative data demonstrated its validity, and all sub-factors were highly reliable. The Turkish version of the VIMSSQ can serve as a valuable tool for estimating individual susceptibility to VIMS. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Family opinions on resuscitation and participation in end-of-life care in the emergency department: A cross-sectional study.
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Akman, Ugur and Koyuncu, Aynur
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TERMINAL care , *HOSPITAL emergency services , *RESUSCITATION , *NUCLEAR families , *CROSS-sectional method - Abstract
OBJECTIVE: The study looked into emergency department family members' (FMs) views on being present during resuscitation and contributing to end-of-life care. METHODS: A cross-sectional study with 467 FM volunteers of mildly injured or ill patients was conducted at a research hospital between October 2021 and May 2022. Data were collected using a questionnaire administered by a clinical psychologist. The analysis employed SPSS 22.0 with a significance threshold of P < 0.05. The study was conducted according to the STROBE criteria. Statistical significance was set at P < 0.05. RESULTS: The mean FMs' age was 34.3 ± 10.43; 64.2% were male, 62.1% were married, and 76.9% had nuclear families. About 61% wanted the option of being present during resuscitation, with 47.5% desiring participation in both resuscitation and end-of-life care. Significant differences were observed in opinions based on education, work status, and resuscitation training (P = 0.015, P = 0.001, P = 0.002). CONCLUSION: Many FMs sought the choice to be present during resuscitation, and nearly half preferred participation in both resuscitation and end-of-life care. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Noether Symmetry Analysis of the Klein–Gordon and Wave Equations in Bianchi I Spacetime.
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Camci, Ugur
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KLEIN-Gordon equation , *WAVE equation , *WAVE analysis , *SPACETIME , *SYMMETRY , *CONSERVATION laws (Physics) - Abstract
We investigate the Noether symmetries of the Klein–Gordon Lagrangian for Bianchi I spacetime. This is accomplished using a set of new Noether symmetry relations for the Klein–Gordon Lagrangian of Bianchi I spacetime, which reduces to the wave equation in a special case. A detailed Noether symmetry analysis of the Klein–Gordon and the wave equations for Bianchi I spacetime is presented, and the corresponding conservation laws are derived. [ABSTRACT FROM AUTHOR]
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- 2024
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14. A note on approximation by some product means in variable exponent Lebesgue spaces.
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Cemal, Hilal Bayindir and Deger, Ugur
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MOTIVATION (Psychology) , *EXPONENTS - Abstract
The approximation by product means in the variable exponent Lebesgue spaces is a problem that has not been addressed before. With this motivation, in this study the speed of approximation of the functions of class (, ()), (0 < ≤ 1) by some product means is obtained with the parameters in the method used as envisioned by Hardy and Littlewood in 1928. [ABSTRACT FROM AUTHOR]
- Published
- 2024
15. Fish Oil Supplementation as an Omega-3 Fatty Acid Source during Gestation: Effects on the Performance of Awassi Ewes and Their Offspring.
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Alshdaifat, Mustafa M., Serbester, Ugur, Obeidat, Belal S., and Gorgulu, Murat
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FISH oils , *OMEGA-3 fatty acids , *EWES , *MILKFAT , *PREGNANCY in animals , *UNSATURATED fatty acids , *FAT - Abstract
Simple Summary: Pregnancy is a critical period in the life cycle of mammals, and proper nutrition plays a pivotal role in the development and health of the offspring. In recent years, there has been a growing interest in the potential benefits of supplementing maternal diets with fish oil, rich in omega-3 fatty acids, during pregnancy. This paper explores the effects of incorporating fish oil into the diet of pregnant ewes on the dams and the development and well-being of lambs. The primary aim of this research was to assess the impact of supplementing fish oil into the diet of pregnant Awassi ewes on various aspects of the dam's productive performance, offspring birth weight, colostrum yield and quality, milk production and composition, postpartum offspring performance, and the composition of fatty acids in milk. In this study, two different fat sources, namely palm oil (PO) and fish oil (FO), were utilized, with both being included at a rate of 2.4% of dietary dry matter (DM) during the initial 65 days of gestation (early gestation stage), and then at 2.1% DM from day 65 of gestation until lambing (late gestation stage). The study subjects were Awassi ewes with a body weight (BW) averaging 57 ± 1.5 kg and an age of 3.5 ± 1.2 years. These ewes were randomly assigned to one of four dietary treatments: (i) a diet containing only palm oil from day 0 to day 150 of pregnancy (PO, n = 15); (ii) a diet containing palm oil from day 0 to day 65 of pregnancy, followed by a diet containing fish oil from day 66 to day 150 of pregnancy (POFO, n = 16); (iii) a diet containing fish oil from day 0 to day 65 of pregnancy, followed by a diet containing palm oil from day 66 to day 150 of pregnancy (FOPO, n = 16); (iv) a diet containing only fish oil from day 0 to day 150 of pregnancy (FO, n = 16). Within each treatment, ewes were housed in three replicates, with each replicate further divided into three subgroups. The first two subgroups each contained eight ewes, while the third subgroup contained nine ewes. In addition, each treatment contained 10 primiparous and 15 multiparous ewes. The results indicated that the POFO treatment led to significant increases (p < 0.05) in birth weight, gestation length, and colostrum IgG concentration. However, it also resulted in a decrease (p < 0.001) in colostrum production and a reduction (p < 0.001) in the percentage of milk fat and milk protein. Furthermore, the milk from the POFO treatment exhibited higher levels of polyunsaturated fatty acids (PUFAs) (p < 0.001) compared to the PO and FOPO treatments, while the milk saturated fatty acids (SFA) were lower (p < 0.001). In conclusion, the addition of fish oil at a rate of 2.1% DM during the late pregnancy period showed promise for enhancing birth weight, colostrum IgG concentration, and the PUFA content in the milk. [ABSTRACT FROM AUTHOR]
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- 2023
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16. Dynamic accommodation measurement using Purkinje reflections and machine learning.
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Ozhan, Faik Ozan, Aygun, Ugur, Sahin, Afsun, and Urey, Hakan
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MACHINE learning , *CRYSTALLINE lens , *EYE tracking , *EYE movements , *CORNEA , *NEUROLOGICAL disorders - Abstract
Quantifying eye movement is important for diagnosing various neurological and ocular diseases as well as AR/VR displays. We developed a simple setup for real-time dynamic gaze tracking and accommodation measurements based on Purkinje reflections, which are the reflections from front and back surfaces of the cornea and the eye lens. We used an accurate eye model in ZEMAX to simulate the Purkinje reflection positions at different focus distances of the eye, which matched the experimental data. A neural network was trained to simultaneously predict vergence and accommodation using data collected from 9 subjects. We demonstrated that the use of Purkinje reflection coordinates in machine learning resulted in precise estimation. The proposed system accurately predicted the accommodation with an accuracy better than 0.22 D using subject's own data and 0.40 D using other subjects' data with two-point calibration in tests performed with 9 subjects in our setup. [ABSTRACT FROM AUTHOR]
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- 2023
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17. Regulatory Effect of Ficus carica Latex on Cell Cycle Progression in Human Papillomavirus-Positive Cervical Cancer Cell Lines: Insights from Gene Expression Analysis.
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Cakir, Muharrem Okan, Bilge, Ugur, Ghanbari, Arshia, and Ashrafi, G. Hossein
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FIG , *HUMAN cell cycle , *CERVICAL cancer , *GENE expression , *CELL lines , *BCL genes - Abstract
Cervical cancer presents a significant global health concern with high-risk human papillomaviruses (HPVs) identified as the main cause of this cancer. Although current treatment methods for cervical cancer can eliminate lesions, preventing metastatic spread and minimizing tissue damage remain a major challenge. Therefore, the development of a safer and innovative therapeutic approach is of the utmost importance. Natural products like fig latex, derived from the Ficus carica tree, have demonstrated promising anti-cancer properties when tested on cervical cancer cell lines. However, the specific mechanisms by which fig latex exerts its effects are still unknown. In this study, we conducted RNA-Seq analysis to explore how fig latex may counteract carcinogenesis in HPV-positive cervical cancer cell lines, namely, CaSki (HPV type 16-positive) and HeLa (HPV type 18-positive). Our results from this investigation indicate that fig latex influences the expression of genes associated with the development and progression of cervical cancer, including pathways related to "Nonsense-Mediated Decay (NMD)", "Cell Cycle regulation", "Transcriptional Regulation by TP53", and "Apoptotic Process". This selective impact of fig latex on cancer-related pathways suggests a potential novel therapeutic approach for HPV-related cervical cancer. [ABSTRACT FROM AUTHOR]
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- 2023
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18. Leakage Problem and Safety Assessment of an Embankment Dam: Investigations and Solution.
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Kilit, Murat, Cavus, Ugur Safak, and Zorluer, Ismail
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EARTH dams , *PORE water pressure , *SLOPE stability , *ROCK slopes , *DAM safety , *FINITE element method , *LEAKAGE - Abstract
This study determines the reason for embankment leakages of a large dam and demonstrates the importance of site evaluations, aside from numerical seepage and slope stability analyses, to assess whether the leakage observed in the embankment dam is related to seepage from the reservoir or from the groundwater that flows into the embankment. Using the software SLIDE, numerical seepage analysis was performed to determine the seepage pattern and pore water pressures. Results revealed that the calculated seepage exit elevation at the embankment's downstream shoulder perfectly matched the measured elevation of the leak. Finite element method seepage analyses showed that reservoir water seeped beyond the dam's chimney filter layer and intersected the downstream slope, which further clarifies that the filter has not functioned well. This study finally puts forth that the leakages are mainly due to the use of a silty sandy soil band together with MH and CH soils compacted excessively on wet side of the optimum moisture content. In addition, through numerical seepage analyses, pore water pressures in the embankment were also calculated for slope stability computations of the embankment. Slope stability analyses showed that safety of the dam slopes is not adequately reliable for even the existing partial impoundment and static loading cases. Thus, this study also suggests that the reservoir water should be kept in an existing partial level and not increased to its designed level. Eventually, the study proposes two remedial measures alternatively and evaluates the best solution. [ABSTRACT FROM AUTHOR]
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- 2023
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19. Novel Predictor of the AF Development in Patients with OSAS: Importance of Visceral Adipose Index.
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OZKAN, Ugur and GURDOGAN, Muhammet
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SLEEP apnea syndromes , *VISCERAL pain , *ATRIAL fibrillation - Abstract
Objective: Obstructive sleep apnea syndrome (OSAS) is a sleep disorder whose frequency is increasing daily due to modern lifestyle. Patients with atrial fibrillation (AF), which has the same predisposing factors, frequently visit the outpatient clinic with complaints of palpitation. Existing symptoms are often associated with the course of OSAS, and the development of AF, a disease with high morbidity and mortality, cannot be detected. In our study, we investigated the relationship between the visceral adiposity index (VAI) and AF development in these patients. Methods: We retrospectively analyzed 207 patients with OSAS who visited the cardiology outpatient clinic. The data of 44 patients with AF and 163 patients without AF were compared. Results: Demographic characteristics and clinical risk factors were similar between the groups (p>0.05). VAI, apnea-hypopnea index, and inflammatory markers were higher in the AF group, and these risk factors were significant in the multivariate analysis (p<0.05). Conclusions: Our study is important in terms of showing VAI as one of the most important predictors of AF, which has an impact on mortality and morbidity in patients with OSAS, whose frequency is increasing daily. Further prospective studies are required to confirm our observations and determine their clinical applicability. [ABSTRACT FROM AUTHOR]
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- 2023
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20. A Sustainable Development Assessment for the Load Capacity Factor and Carbon Footprint in India: The Role of Information and Communication Technologies, Renewable Energy, and Structural Changes.
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Pata, Ugur Korkut and Destek, Mehmet Akif
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INFORMATION & communication technologies , *RENEWABLE energy sources , *SUSTAINABLE development , *ECOLOGICAL impact , *CARBON emissions , *ENVIRONMENTAL quality - Abstract
The increase in India's carbon emissions and the decline in its environmental quality are a threat to the realization of the global sustainable development goals (SDGs). Minimizing the negative environmental impacts from fossil fuels through analysis of the determinants of India's ecological quality is an important research topic. The objective of this study is to examine the impact of information and communication technologies (ICT), renewable energy, and structural changes on environmental quality in India. In this context, the study uses the novel Fourier quantile causality test for the period 1995m1-2021m12. The results of the study show that structural changes have no impact on carbon footprint and load capacity factor, while renewable energy and ICT contribute to the improvement of environmental quality. Based on the findings of the study, the Indian government is recommended to rise investment in ICT and renewable energy to pursue a growth strategy in line with the SDGs. [ABSTRACT FROM AUTHOR]
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- 2023
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21. Satellite–Derived Bathymetry in Shallow Waters: Evaluation of Gokturk-1 Satellite and a Novel Approach.
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Gülher, Emre and Alganci, Ugur
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WATER depth , *BATHYMETRY , *STANDARD deviations , *THEMATIC mapper satellite , *MULTISPECTRAL imaging , *REMOTE sensing , *LANDSAT satellites - Abstract
For more than 50 years, marine and remote sensing researchers have investigated the methods of bathymetry extraction by means of active (altimetry) and passive (optics) satellite sensors. These methods, in general, are referred to as satellite-derived bathymetry (SDB). With the advances in sensor capabilities and computational power and recognition by the International Hydrographic Organization (IHO), SDB has been more popular than ever in the last 10 years. Despite a significant increase in the number of studies on the topic, the performance of the method is still variable, mainly due to environmental factors, the quality of the deliverables by sensors, the use of different algorithms, and the changeability in parameterization. In this study, we investigated the capability of Gokturk-1 satellite in SDB for the very first time at Horseshoe Island, Antarctica, using the random forest- and extreme gradient boosting machine learning-based regressors. All the images are atmospherically corrected by ATCOR, and only the top-performing algorithms are utilized. The bathymetry predictions made by employing Gokturk-1 imagery showed admissible results in accordance with the IHO standards. Furthermore, pixel brightness values calculated from Sentinel-2 MSI and tasseled cap transformation are introduced to the algorithms while being applied to Sentinel-2, Landsat-8, and Gokturk-1 multispectral images at the second stage. The results indicated that the bathymetric inversion performance of the Gokturk-1 satellite is in line with the Landsat-8 and Sentienl-2 satellites with a better spatial resolution. More importantly, the addition of a brightness value parameter significantly improves root mean square error, mean average error, coefficient of determination metrics, and, consequently, the performance of the bathymetry extraction. [ABSTRACT FROM AUTHOR]
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- 2023
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22. Prospective outcome analysis of multiple sclerosis cases reveals candidate prognostic cerebrospinal fluid markers.
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Everest, Elif, Uygunoglu, Ugur, Tutuncu, Melih, Bulbul, Alper, Onat, Umut Inci, Unal, Mehmetcan, Avsar, Timucin, Saip, Sabahattin, Bilge, Ugur, Turanli, Eda Tahir, and Siva, Aksel
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CEREBROSPINAL fluid examination , *HAPTOGLOBINS , *CEREBROSPINAL fluid , *OPTIC neuritis , *MULTIPLE sclerosis , *MAGNETIC resonance imaging , *GAIT disorders , *OPTIC nerve - Abstract
Background: Predicting the long-term disability outcomes of multiple sclerosis (MS) cases is challenging. Objective: We prospectively analysed our previous MS cohort with initial cerebrospinal fluid (CSF) proteomics data to reveal disability markers after 8.2±2.2 years of follow-up. Methods: Patients with regular follow-up visits were assigned into two groups: those with an age-related MS severity (ARMSS) score ≥5 (unfavourable course group, N = 27) and ARMSS score <5 (favourable course group, N = 67). A machine learning-based algorithm was applied to reveal candidate poor prognosis-associated initial CSF proteins, which were measured in an independent MS cohort (verification group, N = 40) by ELISA. Additionally, the correlation of initial clinical and radiological parameters with long-term disability was analysed. Results: CSF alpha-2-macroglobulin (P = 0.0015), apo-A1 (P = 0.0016), and haptoglobin (P = 0.0003) protein levels, as well as cerebral lesion load (>9 lesions) on magnetic resonance imaging, gait disturbance (P = 0.04), and bladder/bowel symptoms (P = 0.01) were significantly higher in the unfavourable course group than in the favourable course group. Optic nerve involvement evident on initial magnetic resonance imaging (P = 0.002) and optic neuritis (P = 0.01) were more frequent in the favourable course group. Conclusion: The herein identified initial CSF protein levels, in addition to the clinical and radiological parameters at disease onset, have predictive value for long-term disability in MS cases. [ABSTRACT FROM AUTHOR]
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- 2023
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23. Carbon efficiency in China: Should we be concerned about the shadow economy and urbanization?
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Pata, Ugur Korkut, Olasehinde‐Williams, Godwin, and Ozkan, Oktay
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INFORMAL sector , *CARBON dioxide mitigation , *CARBON emissions , *URBANIZATION , *KUZNETS curve , *CARBON offsetting - Abstract
Reducing carbon emissions is critical to achieving a carbon‐neutral world according to the Glasgow Climate Pact, but production, and thus carbon emissions, must continue to meet the needs of the world's growing population. Minimizing carbon emissions per production, that is, increasing carbon efficiency is one way to support the Sustainable Development Goals. Therefore, studying the determinants of carbon efficiency for China, the largest global polluter, is important for zero carbon goals. To this end, this study examines the effects of the shadow economy, globalization, trade openness and urbanization on carbon efficiency using novel dynamic autoregressive‐distributed lag simulations for China during 1990–2018. The empirical results illustrate that (i) the environmental Kuznets curve (EKC) hypothesis is not valid; (ii) Shadow economy, trade openness and urbanization reduce carbon efficiency and (iii) Globalization enhances carbon efficiency. Based on these results, it is suggested that the Chinese government should combat the shadow economy to increase carbon efficiency, regulate unplanned and polluting urbanization in a green manner, reduce carbon intensity in foreign trade, and benefit from environmental technologies provided by globalization. [ABSTRACT FROM AUTHOR]
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- 2023
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24. The Prognostic Value of the Novel Global Immune-Nutrition-Inflammation Index (GINI) in Stage IIIC Non-Small Cell Lung Cancer Patients Treated with Concurrent Chemoradiotherapy.
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Topkan, Erkan, Selek, Ugur, Pehlivan, Berrin, Kucuk, Ahmet, Ozturk, Duriye, Ozdemir, Beyza Sirin, Besen, Ali Ayberk, and Mertsoylu, Huseyin
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LUNG cancer , *BIOMARKERS , *STATISTICS , *CONFIDENCE intervals , *NUTRITION , *INFLAMMATION , *MULTIVARIATE analysis , *IMMUNE system , *RETROSPECTIVE studies , *ACQUISITION of data , *CHEMORADIOTHERAPY , *TUMOR classification , *CANCER patients , *DESCRIPTIVE statistics , *MEDICAL records , *RECEIVER operating characteristic curves , *PROGRESSION-free survival , *SENSITIVITY & specificity (Statistics) , *LONGITUDINAL method , *OVERALL survival , *PROPORTIONAL hazards models - Abstract
Simple Summary: We investigated the prognostic significance of the newly created Global Immune-Nutrition-Inflammation Index (GINI) in IIIC non-small cell lung cancer (NSCLC) patients who received definitive concurrent chemoradiotherapy (CCRT). A total of 802 newly diagnosed stage IIIC NSCLC patients were included. The optimal pre-CCRT GINI cutoff was 1562 (area under the curve: 76.1%; sensitivity: 72.4%; specificity: 68.2%; Youden index: 0.406). GINI ≥ 1562 was associated with significantly shorter median locoregional progression-free (p < 0.001), progression-free (p < 0.001), and overall survival (p < 0.001) than GINI < 1562. For each survival endpoint, the association between GINI and survival outcomes appeared independent of other confounding variables (p < 0.05 for each). The novel GINI index effectively stratified patients with stage IIIC NSCLSC into two distinct subgroups, demonstrating significant differences in both median and long-term survival rates. Background: We sought to determine the prognostic value of the newly developed Global Immune-Nutrition-Inflammation Index (GINI) in patients with stage IIIC non-small cell lung cancer (NSCLC) who underwent definitive concurrent chemoradiotherapy (CCRT). Methods: This study was conducted on a cohort of 802 newly diagnosed stage IIIC NSCLC patients who underwent CCRT. The novel GINI created first here was defined as follows: GINI = [C-reactive protein × Platelets × Monocytes × Neutrophils] ÷ [Albumin × Lymphocytes]. The receiver operating characteristic (ROC) curve analysis was used to determine the optimal pre-CCRT GINI cut-off value that substantially interacts with the locoregional progression-free (LRPFS), progression-free (PFS), and overall survival (OS). Results: The optimal pre-CCRT GINI cutoff was 1562 (AUC: 76.1%; sensitivity: 72.4%; specificity: 68.2%; Youden index: 0.406). Patients presenting with a GINI ≥ 1562 had substantially shorter median LRPFS (13.3 vs. 18.4 months; p < 0.001), PFS (10.2 vs. 14.3 months; p < 0.001), and OS (19.1 vs. 37.8 months; p < 0.001) durations than those with a GINI < 1562. Results of the multivariate analysis revealed that the pre-CCRT GINI ≥ 1562 (vs. <1562), T4 tumor (vs. T3), and receiving only 1 cycle of concurrent chemotherapy (vs. 2–3 cycles) were the factors independently associated with poorer LRPS (p < 0.05 for each), PFS (p < 0.05 for each), and OS (p < 0.05 for each). Conclusion: The newly developed GINI index efficiently divided the stage IIIC NSCLSC patients into two subgroups with substantially different median and long-term survival outcomes. [ABSTRACT FROM AUTHOR]
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- 2023
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25. Ficus carica Latex Modulates Immunity-Linked Gene Expression in Human Papillomavirus Positive Cervical Cancer Cell Lines: Evidence from RNA Seq Transcriptome Analysis.
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Cakir, Muharrem Okan, Bilge, Ugur, Naughton, Declan, and Ashrafi, G. Hossein
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FIG , *HUMAN papillomavirus , *CERVICAL cancer , *GENE expression , *CELL lines , *UBIQUITINATION - Abstract
Cervical carcinogenesis is the leading cause of cancer-related deaths in women, and the role of high-risk human papillomavirus (HR-HPV) as a possible risk factor in the development of this cancer is well recognized. Despite the availability of multi-therapeutic approaches, there is still major concern regarding the prevention of metastatic dissemination and excessive tissue injuries. Therefore, it is imperative to develop a safer and more efficient treatment modality. Ficus carica, a natural plant, has shown potential therapeutic properties through its fruit latex when applied to HPV-positive cervical cancer cell lines. However, the mechanisms of action of Ficus carica (fig) latex are not well understood. This study aims to provide a deeper insight into the biological activities of fig latex on human cervical cancer cell lines expressing high-risk HPV types 16 and 18. The data obtained from this study reveal that fig latex influences the expression of genes involved in "Class I MHC-mediated antigen presentation" as well as "Antigen processing: Ubiquitination and Proteasome degradation". These genes play a crucial role in host immune surveillance and the resolution of infection. Notably, Western blot analysis corroborated these findings, demonstrating an increase in the expression of MHC class I in HeLa cells after fig latex treatment. Findings from this study suggest that fig latex may enhance T cell responses against oncogenic HPV, which could be beneficial for the clearance of early-stage cancer. [ABSTRACT FROM AUTHOR]
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- 2023
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26. Hvor er de lavthængende grønne teknologier?
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LADENBURG, JACOB and SOYTAS, UGUR
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En efficient og smidig grøn energiopstilling kræver borgernes accept af de anvendte teknologier. Baseret på svarene fra en repræsentativ landsdækkende spørgeskema under søgelse med svar fra 1.589-1.593 respondenter1 finder vi størst accept af solceller på industritage, fjernvarme, energibesparelser og havvindmølleparker. Måske fordi det er en ny teknologi, er opbakningen til CO2-fangst og -lagring på land og kystnært lille. Der er også lille opbakning til atomkraft. Undersøgelsen viser også, at accepten af specifikke teknologier er afhængige af deres geografiske placering, og der er forskelle i teknologiaccept på tværs af aldersgrupper. [ABSTRACT FROM AUTHOR]
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- 2023
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27. Are elevated mitochondrial DNA fragments in prostatic inflammation a potential biomarker for prostate cancer?
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Aferin, Ugur, Bahtiyar, Nurten, Onaran, Ilhan, and Ozkara, Hamdi
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PROSTATITIS , *PROSTATE cancer , *MITOCHONDRIAL DNA , *BENIGN prostatic hyperplasia , *INFLAMMATION , *BIOMARKERS - Abstract
Background: We sought to determine whether two soluble forms with different size of mtDNA are linked to prostatic inflammation, and whether they discriminate prostate cancer (PCa) from inflammatory prostatic conditions. Methods: Histopathologically diagnosed prostatitis, PCa and benign prostatic hyperplasia patients (n = 93) were enrolled in this study and they were categorized as with and without prostate inflammation. Quantitative RT-PCR was used to analyze the levels of 79-bp and 230-bp fragments in urine and blood samples collected following prostate massage. Results: The urine mtDNA-79 and mtDNA-230 were significantly increased in patients with prostate inflammation compared with those in without inflammation. Here, 79-bp fragment of apoptotic origin was significantly higher level than 230-bp fragment of necrotic origin. Although mtDNA-79 copy number in serum samples was also increased in patients with prostate inflammation, mtDNA-230 was similar in the two groups. Furthermore, mtDNA-79 and mtDNA-230 copy numbers in post-prostate massage urine were higher (about 16-fold and 22-fold, respectively) than those from serum samples. ROC analysis showed that, although post-prostate massage urine have relatively higher performance than blood, ability to discriminate cases of both fragments was not better than that of serum total PSA. Conclusions: Our results demonstrate that shorter cf-mtDNA fragment size in particular, increase in the presence of prostate inflammation in post-prostatic massage urine but both fragments could never improve serum total PSA performance. [ABSTRACT FROM AUTHOR]
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- 2023
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28. The Prognostic Value of the Treatment and Outcome in Patients with Glioblastoma: A Retrospective Cohort Study.
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YAZAR, Ugur, KANDAZ, Mustafa, KIRIMLI, Kaan, and GUVERCIN, Ali Riza
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PROGNOSIS , *GLIOBLASTOMA multiforme , *ISOCITRATE dehydrogenase , *OVERALL survival , *SURVIVAL rate - Abstract
The classification of central nervous system (CNS) tumors by the 2021 World Health Organization (WHO) has led to significant changes in tumor taxonomy. One of the most significant changes is that isocitrate dehydrogenase (IDH) mutant forms of glioblastoma multiforme (GBM) have been differentiated into separate entities, no longer allowing entries to be classified as not otherwise specified (NOS). As a result, this entity only comprises the most aggressive adult-type tumors and established prognostic factors no longer apply. Glioblastoma (GBM) IDH-wildtype CNS WHO grade 4 typically presents necrosis and/or microvascular proliferation and molecular alterations. Herein, we aimed to classify glioblastoma cases to establish a patient survival pattern based on age, gender, the number of masses, tumor location, functional localization, presence of shift, the volume of edema and necrosis, extent of surgery, radiotherapychemotherapy protocol, and isocitrate dehydrogenase (IDH) presence, affecting overall survival were determined retrospectively. A total of 433 patients >20 years old with primary GBM were treated in a single institution between 1996 and 2019. The median survival was 9±0.62 [95% CI 7.78-10.21] months and the survival rate after diagnosis was 39.4% in 1st year, 17% in 2nd year, and 5% in 3rd year. Statistically, age, tumor location, edema, and necrosis were indicated as independent preoperative predictors of prognosis, and younger age at diagnosis, the left temporal and the right occipital location, maximal tumor resection, and administration of temozolomide adjuvant chemotherapy were revealed favorable prognostic factors. [ABSTRACT FROM AUTHOR]
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- 2023
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29. Current Status and Challenges of Oncolytic Virotherapy for the Treatment of Glioblastoma.
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Webb, Mason J., Sener, Ugur, and Vile, Richard G.
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ONCOLYTIC virotherapy , *ELECTRIC field therapy , *BRAIN tumors , *GLIOBLASTOMA multiforme , *IMMUNE checkpoint inhibitors , *PROGRAMMED cell death 1 receptors - Abstract
Despite decades of research and numerous clinical trials, the prognosis of patients diagnosed with glioblastoma (GBM) remains dire with median observed survival at 8 months. There is a critical need for novel treatments for GBM, which is the most common malignant primary brain tumor. Major advances in cancer therapeutics such as immune checkpoint inhibitors and chimeric antigen receptor (CAR) T-cell therapy have not yet led to improved outcomes for GBM. Conventional therapy of surgery followed by chemoradiation with or without tumor treating fields remains the standard of care. One of the many approaches to GBM therapy currently being explored is viral therapies. These typically work by selectively lysing target neoplastic cells, called oncolysis, or by the targeted delivery of a therapeutic transgene via a viral vector. In this review, we discuss the underlying mechanisms of action and describe both recent and current human clinical trials using these viruses with an emphasis on promising viral therapeutics that may ultimately break the field's current stagnant paradigm. [ABSTRACT FROM AUTHOR]
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- 2023
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30. Biomechanical Effects of Angiotensin 1-7 in Diabetes Rats Femur.
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Nalbant, Asrin, Dalaman, Ugur, Gök, Kadir, Duygu, Özden Bedre, Yaras, Nazmi, and Kavak, Servet
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ANGIOTENSINS , *FEMUR , *BIOMARKERS , *LABORATORY rats , *RATS - Abstract
It is known that diabetes mellitus has late complications, including microvascular and macrovascular diseases. Diabetes can affect bones through biochemical markers of bone structure, density, and turnover. This study aimed to biomechanically investigate the bone-protective effects of angiotensin 1-7 (Ang 1-7), one of the active peptides in the renin-angiotensin system, in rats with diabetes. Thirty male Wistar albino rats, three months old and weighing 250-300 g, were divided into four groups: diabetes, Ang 1-7, diabetes plus Ang 1-7, and control. One month later, diabetes developed in rats; the rats were sacrificed, and their right femur was removed. Three-point bending biomechanical tests were performed on the femurs. The diabetic group had significantly higher bone fragility than the other groups (Pr >.05). Bone fragility was lower, and bone flexibility was higher in the Ang 1-7 groups (Pr>F value 0.05). As a result of our study, the effect of Ang 1-7 on the bones of rats with diabetes was investigated biomechanically. Ang 1-7 has a protective impact on the bones of rats with diabetes. [ABSTRACT FROM AUTHOR]
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- 2023
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31. A new sample reduction method for decreasing the running time of the k-nearest neighbors algorithm to diagnose patients with congestive heart failure: backward iterative elimination.
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Isler, Yalcin, Ozturk, Ugur, and Sayilgan, Ebru
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CONGESTIVE heart failure , *K-nearest neighbor classification , *HEART failure patients , *SYMBOLIC dynamics , *TIME-domain analysis , *NAIVE Bayes classification - Abstract
The model complexity is strictly connected to both the sample size and the number of features in a conventional pattern recognition study. Although there are some sample reduction methods in the literature, they cannot give the highest classifier performance or are not able to achieve the minimum number of samples in general. In this study, we offered a new sample reduction method, named Backward Iterative Elimination. To show its efficiency, we classified congestive heart failure (CHF) patients and healthy subjects from heart rate variability (HRV) features using the k-nearest neighbors (kNN) classifier. We extracted 59 HRV features (time and frequency domain measurements through power spectral density estimates of different transformation methods in addition to nonlinear measures calculated from Poincare plot, sample entropy, symbolic dynamics, and detrended fluctuation analysis) from databases provided by the Massachusetts Institute of Technology and Boston's Beth Israel Hospital. The extracted features were classified using kNN with various odd k values from 1 to 19. The proposed method was compared to three well-known reduction methods: Backward elimination, Gaussian elimination, and Genetic algorithm. The proposed system yielded the highest accuracy values for each "k" value. While the genetic algorithm achieved the maximum sample size reduction in general, the proposed method showed better sample size reduction performance than other backward elimination methods. The method resulted in a classifier accuracy of 87.95% with 33 samples only. In this case, the algorithm run time reduces to 9.1411 ms, which is 12.1578 ms using all samples. In conclusion, the "Backward Iterative Elimination" gives the highest classifier performances with an appropriate ratio in sample size reduction so that it can be utilized in pattern recognition studies as a good alternative. [ABSTRACT FROM AUTHOR]
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- 2023
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32. Satellite-Derived Bathymetry Mapping on Horseshoe Island, Antarctic Peninsula, with Open-Source Satellite Images: Evaluation of Atmospheric Correction Methods and Empirical Models.
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Gülher, Emre and Alganci, Ugur
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LANDSAT satellites , *BATHYMETRY , *TERRITORIAL waters , *DEEP learning , *EMPIRICAL research , *REMOTE-sensing images , *OCEAN color - Abstract
Satellite-derived bathymetry (SDB) is the process of estimating water depth in shallow coastal and inland waters using satellite imagery. Recent advances in technology and data processing have led to improvements in the accuracy and availability of SDB. The increased availability of free optical satellite sensors, such as Landsat missions and Sentinel 2 satellites, has increased the quantity and frequency of SDB research and mapping efforts. In addition, machine learning (ML)- and deep learning (DL)-based algorithms, which can learn to identify features that are indicative of water depth, such as color or texture variations, have started to be used for extracting bathymetry information from satellite imagery. This study aims to produce an initial optical image-based SBD map of Horseshoe Island's shallow coasts and to perform a comprehensive and comparative evaluation with Landsat 8 and Sentinel 2 satellite images. Our research considers the performance of empirical SDB models (classical, ML-based, and DL-based) and the effects of the atmospheric correction methods ACOLITE, iCOR, and ATCOR. For all band combinations and depth intervals, the ML-based random forest and XGBoost models delivered the highest performance and best fitting ability by achieving the lowest error with MAEs smaller than 1 m up to 10 m depth and a maximum correlation of R2 around 0.80. These models are followed by the DL-based ANN and CNN models. Nonetheless, the non-linearity of the reflectance–depth connection was significantly reduced by the ML-based models. Furthermore, Landsat 8 showed better performance for 10–20 m depth intervals and in the entire range of (0–20 m), while Sentinel 2 was slightly better up to 10 m depth intervals. Lastly, ACOLITE, iCOR, and ATCOR provided reliable and consistent results for SDB, where ACOLITE provided the highest automation. [ABSTRACT FROM AUTHOR]
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- 2023
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33. Splenic mesothelial cyst: a case report.
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Kesici, Ugur, Ayvazoglu, Mustafa, Celik, Yigitcan, and Yalcin, Orhan
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CYSTS (Pathology) , *YOUNG adults , *SPLENECTOMY , *SPLEEN - Abstract
Splenic cyst was first described by Andral in 1929. Splenic cysts are divided into 2 groups as parasitic and non-parasitic. Splenic mesothelial cyst (SMC) is a rare form of splenic cysts, and its incidence is not known exactly. It is frequently observed in children and young adults. In this case report, a 21-year-old male patient who underwent laparoscopic splenectomy with a diagnosis of symptomatic splenic cyst is discussed. Total splenectomy was decided because of the splenic cyst localization in the splenic hilus. Laparoscopic splenectomy was performed to the patient. SMC is a rare primary splenic cyst and is usually asymptomatic. It is often detected incidentally by imaging modalities. Symptomatic cysts with a size of more than 5 cm should be treated. Spleen sparing techniques are accepted as the current treatment option. In this case report, a young adult patient who underwent laparoscopic splenectomy for symptomatic SMC is discussed in the light of the literature. [ABSTRACT FROM AUTHOR]
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- 2023
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34. Strategic Electricity Production Planning of Turkey via Mixed Integer Programming Based on Time Series Forecasting.
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Yörük, Gökay, Bac, Ugur, Yerlikaya-Özkurt, Fatma, and Ünlü, Kamil Demirberk
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PRODUCTION planning , *INTEGER programming , *BOX-Jenkins forecasting , *TIME series analysis , *DEMAND forecasting , *POWER resources , *FORECASTING - Abstract
This study examines Turkey's energy planning in terms of strategic planning, energy policy, electricity production planning, technology selection, and environmental policies. A mixed integer optimization model is proposed for strategic electricity planning in Turkey. A set of energy resources is considered simultaneously in this research, and in addition to cost minimization, different strategic level policies, such as CO2 emission reduction policies, energy resource import/export restriction policies, and renewable energy promotion policies, are also considered. To forecast electricity demand over the planning horizon, a variety of forecasting techniques, including regression methods, exponential smoothing, Winter's method, and Autoregressive Integrated Moving Average methods, are used, and the best method is chosen using various error measures. The optimization model constructed for Turkey's Strategic Electricity Planning is obtained for two different planning intervals. The findings indicate that the use of renewable energy generation options, such as solar, wind, and hydroelectric alternatives, will increase significantly, while the use of fossil fuels in energy generation will decrease sharply. The findings of this study suggest a gradual increase in investments in renewable energy-based electricity production strategies are required to eventually replace fossil fuel alternatives. This change not only reduces investment, operation, and maintenance costs, but also reduces emissions in the long term. [ABSTRACT FROM AUTHOR]
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- 2023
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35. Design, Implementation and Test of a Novel Cylindrical Permanent Magnet DC Linear Motor.
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Demirkol, Ziya, Hasirci, Ugur, and Demirci, Recep
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CIRCULAR motion , *ELECTRIC motors , *ELECTRICAL energy , *NUMERICAL analysis , *PERMANENT magnets , *DESIGN - Abstract
Electric motors that convert electrical energy into motion are one of the basic components of automation systems. In these systems, either linear or circular motion is needed. Linear motion can be obtained either from motors that generate circular motion with the help of ancillary equipment or directly by the means of a linear motor. Obtaining linear motion from motors that produce rotary motion leads to additional costs and reduced efficiency. Linear motors, on the other hand, eliminate the need for conversion mechanisms. Despite this advantage, linear motors have some disadvantages, such as length limitation and low force/current ratio. In this study, a novel Cylindrical Direct Current Linear Motor (CDCLM) with high force/current ratio and no length limitation (long stroke) has been developed. Analyses of the developed motor has been performed with an analytical method. In addition, detailed numerical analyses have been carried out in an Ansys-Maxwell environment. A prototype of the designed DC linear motor has been implemented in a laboratory environment and experimental analyses have been carried out. The results of analytical, numerical and experimental analyses have been compared. [ABSTRACT FROM AUTHOR]
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- 2023
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36. Navigating the Impact of Renewable Energy, Trade Openness, Income, and Globalization on Load Capacity Factor: The Case of Latin American and Caribbean (LAC) Countries.
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Pata, Ugur Korkut, Kartal, Mustafa Tevfik, Dam, Mehmet Metin, and Kaya, Funda
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RENEWABLE energy sources , *ENVIRONMENTAL quality , *ECONOMIC globalization , *INTERNATIONAL trade , *GLOBALIZATION - Abstract
Considering relatively high but recently decreasing environmental quality in the LAC countries with regard to the world, this study uncovers the progress of environmental quality, which is proxied by load capacity factor (LCF). In this context, the study considers renewable energy, trade openness, income, and globalization as explanatory indicators; uses data from 1990 to 2018; applies pooled mean group autoregressive distributed lag (PMG-ARDL) approach as the main model; and performs panel Toda-Yamamoto (PTY) causality test as robustness model. This is important because the LAC countries have ecological reserves, whereas many countries have an ecological deficit. For this reason, the investigation of the LAC countries has significance for the environmental quality in the world. Also, this study has novelty in terms of examining LAC countries and using the LCF as the environmental quality. The results present that (i) renewable energy has an improving impact on the LCF in both the short run and the long run; (ii) trade openness has a stimulating impact on the LCF in the long run; (iii) however, globalization and economic growth have a degrading impact on the LCF in the long run. Hence, it can be drawn from the results that renewable energy and trade openness have a critical impact on preserving and developing environmental quality. In line with the empirical findings, it can be proposed that LAC countries should utilize renewable energy effectively, improve trade volume through trade openness, increase renewable energy technology import, and expand the use of renewable energy in foreign trade activities. Thus, effective renewable energy and foreign trade policies can promote the achievement of sustainable development goals (SDGs) in the LAC countries. [ABSTRACT FROM AUTHOR]
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- 2023
- Full Text
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37. The effect of the ATM inhibitor AZD0156 on the radiosensitivity of human breast cancer and lung fibroblast cells.
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Yilmaz, Ugur, Kamer, Deniz, Asik, Aycan, Kara, Hale G., Gündüz, Cumhur, and Kamer, Serra
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RADIATION tolerance , *BREAST cancer , *LUNG cancer , *FIBROBLASTS , *CELL cycle , *ESTROGEN - Abstract
Aims: To evaluate the effect of the combination of irradiation and AZD0156 on apoptosis, cell cycle progression, and clonogenic survival in human breast cancer and fibroblast cells. Methods and Material: Estrogen receptor‑positive breast cancer cell line MCF‑7 and healthy lung fibroblast cell line WI‑38 were obtained. Following employing proliferation analysis, cytotoxicity analysis was done to calculate the IC50 values of AZD0156 in MCF‑7 and WI‑38 cell lines. Following the application of AZD0156 and irradiation, flow cytometry analysis was performed for evaluating cell cycle distribution and the extent of apoptosis. Plating efficiency and surviving fraction were calculated for the clonogenic assay. Statistical Analysis Used: SPSS Statistics for Windows, Version 17.0. (SPSS Inc. Chicago) and GraphPad Prism Version 6.0 for Windows (GraphPad Software, San Diego, California USA) softwares were used to analyze data. Results: AZD0156 and irradiation dose of 2–10 Gy had no effect on apoptosis on MCF‑7 cells. The combination treatment of AZD0156 and 2 Gy, 4 Gy, 6 Gy, 8 Gy, and 10 Gy irradiation induced G0 /G1 phase arrest by 1.79, 1.79, 1.50, 1.25, and 1.52‑fold compared to the control group, respectively on MCF‑7 cell lines. Combination treatment of AZD0156 and each different irradiation dose affected clonogenic survival owing to increased radiosensitivity(p: 0.02). AZD0156 and irradiation dose of 2 Gy, 4 Gy, 6 Gy, 8 Gy, and 10 Gy decreased the cell viability rate of WI‑38 cells by 1.05, 1.18, 1.22, 1.04, and 1.05‑fold compared to the control group, respectively. No efficacy was detected on cell cycle analysis, and clonogenic survival was not significantly decreased in WI‑38 cells. Conclusion: The combination use of irradiation and AZD0156 has improved efficacy of tumor cell‑specific cell cycle arrest and decreasing clonogenic survival. [ABSTRACT FROM AUTHOR]
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- 2023
- Full Text
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38. Necessary Condition of Self-Organisation in Nonextensive Open Systems.
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Afsar, Ozgur and Tirnakli, Ugur
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PHASE space , *RENORMALIZATION (Physics) , *ENTROPY , *ENERGY policy , *STATE laws - Abstract
In this paper, we focus on evolution from an equilibrium state in a power law form by means of q-exponentials to an arbitrary one. Introducing new q-Gibbsian equalities as the necessary condition of self-organization in nonextensive open systems, we theoretically show how to derive the connections between q-renormalized entropies ( Δ S ˜ q ) and q-relative entropies ( K L q ) in both Bregman and Csiszar forms after we clearly explain the connection between renormalized entropy by Klimantovich and relative entropy by Kullback-Leibler without using any predefined effective Hamiltonian. This function, in our treatment, spontaneously comes directly from the calculations. We also explain the difference between using ordinary and normalized q-expectations in mean energy calculations of the states. To verify the results numerically, we use a toy model of complexity, namely the logistic map defined as X t + 1 = 1 − a X t 2 , where a ∈ [ 0 , 2 ] is the map parameter. We measure the level of self-organization using two distinct forms of the q-renormalized entropy through period doublings and chaotic band mergings of the map as the number of periods/chaotic-bands increase/decrease. We associate the behaviour of the q-renormalized entropies with the emergence/disappearance of complex structures in the phase space as the control parameter of the map changes. Similar to Shiner-Davison-Landsberg (SDL) complexity, we categorize the tendencies of the q-renormalized entropies for the evaluation of the map for the whole control parameter space. Moreover, we show that any evolution between two states possesses a unique q = q * value (not a range for q values) for which the q-Gibbsian equalities hold and the values are the same for the Bregmann and Csiszar forms. Interestingly, if the evolution is from a = 0 to a = a c ≃ 1.4011 , this unique q * value is found to be q * ≃ 0.2445 , which is the same value of q s e n s i t i v i t y given in the literature. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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39. Evaluation of hematological parameters in patients using systemic isotretinoin with diagnosis of acne vulgaris.
- Author
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Demirci Saadet, Elif and Sahin, Ugur
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LEUKOCYTE count , *ACNE , *MEAN platelet volume , *ISOTRETINOIN , *NEUTROPHIL lymphocyte ratio - Abstract
Objectives: Oral isotretinoin is the most effective treatment option in patients with acne. However, it can cause various hematologic and biochemical abnormalities. This study aimed to evaluate hematologic abnormalities during oral isotretinoin treatment in patients with acne. Material and Methods: In this cross‐sectional study, the hematologic and inflammatory parameters of 138 patients with acne using 0.3‐1 mg/kg/day oral isotretinoin for at least 6 months were retrospectively analyzed. Results: In the study, the female‐to‐male ratio was 2.83, and the mean age of the patients was 23.1 ± 5.8 years. At the third and sixth months of isotretinoin treatment, there was a statistically significant decrease in the neutrophil count compared to the pre‐treatment values (p = 0.003 and p = 0.032, respectively). The platelet count showed the most statistically significant increase (p < 0.001) at the first month of treatment. The most statistically significant decrease in the neutrophil‐to‐lymphocyte ratio (NLR) was observed at the third month of treatment (p < 0.001). No significant changes were observed in hemoglobin, hematocrit, white blood cell count, mean corpuscular volume, and mean platelet volume. Conclusions: There was a decrease in neutrophils and NLR and an increase in platelets during isotretinoin treatment, and these changes were usually mild. However, it would be appropriate to monitor blood counts during treatment in patients with neutropenia or thrombocytosis. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
40. A NEW TROCHOIDAL TOOLPATH IN MILLING OPERATIONS.
- Author
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Kiyak, Murat, Emiroglu, Ugur, and Bastekeli, E. Orhun
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CUTTING force , *MILLING (Metalwork) , *MECHANICAL alloying , *ENGRAVING , *MANUFACTURING industries - Abstract
The milling is a widely used method in the manufacturing industry, especially in the production of complex engravings such as die&molds. Rough milling often requires a large material removal rate in a short time. This purpose also requires the selection and use of the best milling tool path. Today, trochoidal milling is receiving more attention than conventional milling, especially as it significantly increases tool life. In this study, a new toolpath model for trochoidal milling is suggested and this proposed toolpath model is examined in terms of cutting temperature, cutting force, surface quality, tool wear. In this new trochoidal toolpath model proposed for the milling method, the cutting force did not change much compared to the standard trochoidal tool path, but better surface quality and less tool wear were observed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
41. Imaging features of radiation-induced lung disease and its relationship with clinical and dosimetric factors in breast cancer patients.
- Author
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Yilmaz, Ugur, Koylu, Murat, Savas, Recep, and Alanyali, Senem
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MEDICAL dosimetry , *LUNG diseases , *CANCER patients , *BREAST cancer , *INTERSTITIAL lung diseases , *RECEIVER operating characteristic curves - Abstract
Aim: The aim is to extensively evaluate imaging features of radiation induced lung disease in breast cancer patients and to determine the relationship of imaging alterations with dosimetric parameters and patient related characteristics. Materials and Methods: A total of 76 breast cancer patients undergoing radiotherapy (RT) were studied retrospectively by case notes, treatment plans, dosimetric parameters, and chest computed tomography (CT) scans. Time intervals, that chest CT scans were acquired, were grouped as 1-6 months, 7-12 months, 13-18 months and more than 18 months after RT. Chest CTs (one or more for each patient) were assessed for the presence of ground glass opacity, septal thickening, consolidation/patchy pulmonary opacity/alveolar infiltrates, subpleural air cyst, air bronchogram, parenchymal bands, traction bronchiectasis, pleural/subpleural thickening and pulmonary volume loss. These alterations were scored by applying a system devised by Nishioka et al. Nishioka scores were analyzed for the relationship with clinical and dosimetric factors. Statistical Analysis Used: IBM SPSS Statistics for Windows, version 22.0 (IBM Corp., Armonk, N.Y., USA) was used to analyze data. Results: Median follow-up time was 49 months. Advanced age and aromatase inhibitor intake were correlated with higher Nishioka scores for 1-6 months' period. However, both were found nonsignificant in multivariate analysis. Nishioka scores of CT scans acquired more than 12 months after RT were positively correlated with mean lung dose, V5, V20, V30, and V40. Receiver operating characteristic analysis revealed that V5 for ipsilateral lung was the most robust dosimetric parameter predicting chronic lung injury. V5 >41% indicates the development of radiological lung changes. Conclusions: Keeping V5 =41% for ipsilateral lung could provide avoiding chronic lung sequelae. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
42. Evaluation of Afamin Level after Bariatric Surgery in Patient with Obesity.
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Demircioglu, Hilmi, Dogan, Ugur, Ellidag, Hamit Yasar, Aslaner, Arif, and Oner, Osman Zekai
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BARIATRIC surgery , *GASTRIC bypass , *SLEEVE gastrectomy , *THYROTROPIN , *BODY mass index , *WEIGHT loss - Abstract
Background: The aim of this study is to evaluate afamin levels after weight loss in obese patients who underwent laparoscopic sleeve gastrectomy (LSG) and to investigate the relationship between them. In addition, after bariatric surgery, thyroid stimulating hormone (TSH), thyroxine (T4), low-density lipoprotein (LDL), very low-density protein (VLDL), total cholesterol, triglyceride (TG), high-density lipoprotein (HDL), insulin, and hemoglobin A1c (HgbA1c) levels were evaluated. Methods: Preoperative and postoperative 6th month venous blood samples were obtained from 43 patients included in this study. The preoperative and postoperative 6th month body mass index (BMI), TG, total cholesterol, VLDL, HDL, insulin, HgbA1c, TSH, T4, and afamin levels of the patients who underwent bariatric surgery with obesity were compared. Results: Serum afamin levels of patients decreased at 6 months postoperatively; however, it was not statistically significant. We observed a statistically significant decrease in patients' BMI, HDL, VLDL, TG, total cholesterol, TSH, T4, HgbA1c, and insulin values (p < 0.05). There were significant increases in HDL and T4 values. The change in LDL value was statistically insignificant. Conclusions: Recent studies have shown that there may be a cause–effect relationship between afamin and obesity. In our study, we observed a decrease in serum afamin levels after weight loss following bariatric surgery. In addition, we think that afamin may be used as a potential marker of metabolic syndrome in the future and may lead to improvements in the medical treatment of obesity. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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43. Effect of Large Height Difference on Global Positioning System Solutions from a Commercially Available Software Package.
- Author
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Erol, Tuna and Sanli, D. Ugur
- Abstract
Commercially available global navigation satellite system (GNSS) processing software is user-friendly and can be used in a wide variety of positioning applications from establishing geodetic control over large regions to deformation monitoring on a local scale. It is important to study the accuracy of positioning from commercial software for presurvey planning. Previously, this was done in several studies; however, none of them focused on the effect of large height differences in positioning solutions. It is known in the literature that large height differences on a baseline degrade GNSS solutions. In this study, we investigate the effect using TOPCON MAGNET v 4.0.1 through analysis of continuously operating reference stations (CORS) in California, US. Because the effect of height differences on global positioning system (GPS) baseline components has not yet been properly quantified, the positioning accuracy standards given in the surveying guidelines may not be appropriate and are often overoptimistic. When the height difference was less than about 300 m, the root mean square error was about 2–3 mm for the horizontal components and about 20 mm for the vertical component for baseline lengths of 10–20 km. However, for a height difference of 1,500 m, the error became 5–8 mm for the horizontal and 70 mm for the vertical components. In all cases, the vertical error was greater than the horizontal by a factor of 5–9, which is much greater than the expected 2–4 for GNSS. These results are likely only applicable to the version of the MAGNET software used in this study. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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44. Making performance analysis of on grid photovoltaic energy systems: Example of Turkey.
- Author
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Kılıç, Ugur and Kesen, Ugur
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ALTERNATIVE fuels , *RENEWABLE natural resources , *SOLAR energy , *PHOTOVOLTAIC power systems , *SOLAR cells , *FOSSIL fuels - Abstract
The globalizing world and the rapid increase in industrialization and urbanization rates have increased the world’s need for energy day by day, making energy one of the most important agenda items of the world. Increasing demand has led the countries to ensure supply-demand balance to become one of the basic energy policies. One of these prominent energy policies is to ensure diversity in supply and to turn towards renewable resources that are not dependent on exhausted fossil fuels. One of these renewable sources is photovoltaic (solar cell) energy generation systems that generate electrical energy from solar energy. Solar energy is a good alternative to fossil fuels as it has an environmentally clean source feature. In this study, the performance evaluations of power plants were made by comparing the simulation results with data obtained from established fields in three different geographical regions of Turkey. In addition, regional production efficiency was analyzed by comparing the production values of the plants among themselves. An interface program that analyzes instant power plant values was designed, and a practical evaluation software was created. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
45. Chimeric antigen receptor T cells as adjuvant therapy for unresectable adenocarcinoma.
- Author
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Uslu, Ugur, Tong Da, Assenmacher, Charles-Antoine, Scholler, John, Young, Regina M., Tchou, Julia, and June, Carl H.
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WOUND healing , *CHIMERIC antigen receptors , *T cells , *T cell receptors , *CRYOPRESERVATION of cells , *CELLULAR therapy , *CYTOTOXIC T cells - Abstract
The article presents a study which explores how chimeric antigen receptor T cells (CARTs) act as adjuvant therapy for unresectable adenocarcinoma. It mentions that study finds that local delivery of CARTs in a fibrin glue–based carrier was effective in clearing residual cancer cells following incomplete surgery.
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- 2023
- Full Text
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46. Experimental Investigation of the Electrical Wiring Configuration of the HK40 Hall Thruster Operation.
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Kokal, Ugur, Turan, Nazli, and Celik, Murat
- Subjects
- *
HALL effect thruster , *HALL effect , *VACUUM chambers , *THRUST , *CATHODES , *ORBITS (Astronomy) - Abstract
Vacuum chambers providing a low pressure environment similar to the vacuum environment in low earth orbit have been used for the testing of plasma thrusters. A signi!cant proportion of research on the e"ects of vacuum facility on plasma thrusters has focused on the e"ects of background pressure and plume expansion; however, the electrical interaction of the conductive chamber walls with the plasma thrusters needs to be explored further. In this study, the operation of a prototype Hall thruster, HK40, was investigated to understand the e"ects of wiring con!guration of the thruster-cathode-chamber system. During the tests, the thruster was operated in two di"erent grounding con!gurations. A resistance analogy regarding the changes in the electrical potentials and measured currents was introduced. #e calculated thrust and e$ciency values of the two con!gurations were compared. #is study shows that the current extracted from the emitter surface of the cathode, along with the cathode-toground voltage can be used to estimate the thrust and thruster e$ciency. In addition, the theoretical predictions were compared with the values based on the measurements made with an in-house-built inverted pendulum type thrust stand. #e presented results show that the thrust and e$ciency values are predicted with 3.4% and 8.3% uncertainty, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
47. Comparison of Particle Shape, Surface Area, and Color Properties of the Calcite Particles Ground by Stirred and Ball Mill.
- Author
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Ulusoy, Ugur, Çayirli, Serkan, Bayar, Guler, and Gokcen, Hasan Serkan
- Subjects
- *
BALL mills , *SURFACE area , *CALCITE , *IMAGE analysis , *CALCIUM carbonate , *PLASTICS industries - Abstract
Since the particle size, shape, specific surface area, and purity of the ground calcium carbonate (GCC) decide its usability in the paper, paint, and plastic industries, the effect of grinding is important. However, the effect of stirred and ball mill grinding on the particle shape of GCC by dynamic image analysis (DIA) is still lacking in the literature. Therefore, the aim of this study is to compare the aspect ratio at the same fineness (d97 = 50 μm) and evaluate other properties such as color, and surface area of GCC particles by stirred and ball mill grindings. DIA results showed that particles produced by the ball mill had higher aspect ratio values than those by the stirred mill. This was attributed to the impact, and attrition breakage modes produced by the ball and stirred mill, respectively. This conclusion is supported by XRD and SEM. Finally, the results related to physical properties such as aspect ratio, surface area, and whiteness are discussed depending on the usage area of GCC. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
48. A Review of Particle Shape Effects on Material Properties for Various Engineering Applications: From Macro to Nanoscale.
- Author
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Ulusoy, Ugur
- Subjects
- *
MANUFACTURING processes , *ENGINEERING , *INDUSTRIAL property , *INDUSTRIAL minerals , *NANOSTRUCTURED materials - Abstract
It is well known that most particle technology studies attempting to predict secondary properties based on primary properties such as size and shape begin with particle characterization, which means the process of determining the primary properties of particles in a wide spectrum from macro to nanoscale. It is a fact that the actual shape of engineering particles used in many industrial applications or processes is neglected, as they are assumed to be "homogeneous spheres" with easily understood behavior in any application or process. In addition, it is vital to control the granular materials used in various industries or to prepare them in desired shapes, to develop better processes or final products, and to make the processes practical and economical. Therefore, this review not only covers basic shape definitions, shape characterization methods, and the effect of particle shape on industrial material properties, but also provides insight into the development of the most suitably shaped materials for specific applications or processes (from nanomaterials used in pharmaceuticals to proppant particles used in hydrocarbon production) by understanding the behavior of particles. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
49. Advancements in Applied Geoinformatics.
- Author
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Paziewski, Jacek and Sanli, Dogan Ugur
- Subjects
- *
GEOINFORMATICS , *STRUCTURAL health monitoring , *GLOBAL Positioning System - Published
- 2023
- Full Text
- View/download PDF
50. Effects of Silica Fume and Micro Silica on the Properties of Mortars Containing Waste PVC Plastic Fibers.
- Author
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Mahmood, Rawa Ahmed and Kockal, Niyazi Ugur
- Subjects
- *
SILICA fume , *PLASTIC fibers , *CONSTRUCTION materials , *DUCTILITY , *POROSITY - Abstract
Investigations on the usability of waste plastics as a new generation of construction materials have become one of the main concerns of researchers and engineers in recent decades. Waste plastics can be used either as aggregate replacement or as fiber reinforcement to enhance the properties of cementitious mixtures. This study focuses on the properties of waste PVC fiber-reinforced mortars containing silica fume and micro silica. Plastic fibers were added to the mortar mixes by volume fractions of 0%, 1%, 2%, and 3%. Cement was replaced by micro silica and silica fume by 5%, 10%, and 15% by weight of cement, respectively. In total, 28 different groups of mortars were produced. The results showed an enhanced ductility and deformation behavior of mortars upon the addition of waste PVC plastic fibers. It can be seen that fibers restricted crack propagation and maintained integrity, hence improving the ductility of the mortars. On the other hand, the addition of fibers led to a reduction in the physical and mechanical properties of the mortar samples. The compressive strength of the mortar samples decreased gradually by increasing the fiber content. Cement replacement by silica fume improved mechanical and microstructural properties of the mortars. The results also demonstrated that silica fume significantly decreased the porosity and water absorption capacity of mortar samples. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
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