15 results on '"Enver Özdemir"'
Search Results
2. A Transitional Cell Tumor of the Bladder in a Young Adult: A Case Report and Review of the Literature
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Hüseyin Koçan, Şiir Yıldırım, Enver Özdemir, Mehmet Yazıcı, Erhan Erdoğan, Fuat Ernis Su, and Mehmet Uhri
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Bladder ,transitional cell tumor ,young adult ,Surgery ,RD1-811 ,Diseases of the genitourinary system. Urology ,RC870-923 - Abstract
Bladder tumors are rarely seen in young people under the age of 40. Its development after the exposure to industrial carcinogens for many years suggests that the environmental factors play a significant role in the development of transitional cell carcinoma of the bladder. The low prevalence of transitional cell carcinoma of the bladder in young people supports the existence of genetic component. Herewith, we present an 18-year-old patient without a history of exposure to any chemical agent and a review of the relevant literature.
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- 2017
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3. Case Report of a Man With Sertoli Cell Only, Transverse Testicular Ectopia, and External Auditory Canal Atresia
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Enver Özdemir, Hüseyin Koçan, Mehmet Yazıcı, Erçin Altıok, Fuat E. Su, and Mehmet N. Güneş
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Transverse testicular ectopia ,Sertoli cell only syndrome ,External ear canal atresia ,Diseases of the genitourinary system. Urology ,RC870-923 - Abstract
Transverse testicular ectopia (TTE) is an uncommon congenital anomaly, reported mostly as pediatric case reports. Herewith we report a 43-year old man presenting with sertoli cell only, Transverse testicular ectopia and external auditory canal atresia.
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- 2015
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4. Independent risk factors affecting hemorrhage in percutaneous nephrolithotomy: Retrospective study
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Enver Özdemir and Huseyin Kocan
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Adult ,Male ,Risk Factors ,Humans ,Female ,Hemorrhage ,Nephrolithotomy, Percutaneous ,Obesity ,General Medicine ,Plaque, Atherosclerotic ,Retrospective Studies - Abstract
The perioperative and postoperative concern in percutaneous nephrolithotomy (PNL) is bleeding. Disease-related conditions (such as stone size, stone HU, tract number, and diameter) affecting this situation were determined. To determine independent risk factors that may affect the amount of hemorrhage in PNL.A total of 308 adult patients (211 men, 97 women) undergoing the PNL procedure were included in the study. Renal anatomy and stone size were evaluated using non-contrast thin-section computed tomography (NCCT). NCCT was used to assess Hounsfield unit (HU) values of kidney stones, presence of atheroma plaque and obesity. The difference between preoperative hemoglobin (Hgb) values and postoperative 1st day Hgb values was recorded. This variation was evaluated for the effect of gender, age, atherosclerotic vein disease, urine pH and density, leukocyte count, lymphocyte count, neutrophil count (NEU), platelet count, mean platelet volume (MPV), neutrophil lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), stone volume, HU, and obesity.The mean Hgb variation was identified as 2.1 (standard deviation: 1.6). There were positive, significant, and weak correlations between the Hgb variation with NEU (P=0.019), MPV (P=0.000), NLR (P=0.005), stone volume (P=0.041) and HU (P=0.024) values. There was a negative significant and weak correlation between Hgb variation and PLT (P=0.022). No effects at significant levels were identified for gender (P=0.078), presence of atheroma plaque (P=0.949), obesity (P=0.869), age (P=0.686), urine pH (P=0.746), urine density (P=0.421), and PLR (P=0.855) on Hgb variations.In addition to HU and stone volume, NEU count, MPV, NLR and PLT count may be used as independent risk factors to predict blood loss during PNL.
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- 2022
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5. A Hierarchical Key Assignment Scheme: A Unified Approach for Scalability and Efficiency
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Ibrahim Celikbilek, Baris Celiktas, and Enver Ozdemir
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Hierarchical key assignment ,access control ,closest vector problem ,inner product space ,access graph ,strong key indistinguishability ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
This study introduces a hierarchical key assignment scheme (HKAS) based on the closest vector problem in an inner product space (CVP-IPS). The proposed scheme offers a comprehensive solution with scalability, flexibility, cost-effectiveness, and high performance. The key features of the scheme include CVP-IPS based construction, the utilization of two public keys by the scheme, a distinct basis set designated for each class, a direct access scheme to enhance user convenience, and a rigorous mathematical and algorithmic presentation of all processes. This scheme eliminates the need for top-down structures and offers a significant benefit in that the lengths of the basis sets defined for classes are the same and the costs associated with key derivation are the same for all classes, unlike top-down approaches, where the higher class in the hierarchy generally incurs much higher costs. The scheme excels in both vertical and horizontal scalability due to its utilization of the access graph and is formally proven to achieve strong key indistinguishability security (S-KI-security). This research represents a significant advancement in HKAS systems, providing tangible benefits and improved security for a wide range of use cases.
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- 2024
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6. A Molecularly Imprinted Polymer Based Biosensor for Electrochemical Impedance Spectroscopic Analysis
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Melahat Sevgül Sevgül Bakay, Ozan Enver Özdemir, Feride Şermin Utku, Utku, Feride Şermin, Özdemir, Ozan Enver, Bakay, Melahat Sevgül, and Yeditepe Üniversitesi
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Auxiliary electrode ,Working electrode ,Materials science ,Elektrik ve Elektronik ,Molecularly imprinted polymer ,Mühendislik ,Reference electrode ,Dielectric spectroscopy ,Engineering ,Chemical engineering ,Electrode ,Molecularly Imprinted Polymer,Cyclic Voltammetry,Electrochemical Impedance Spectroscopy,tris(hydroxymethyl)aminomethane,Pencil Graphite Electrode ,Electrical and Electronic Engineering ,Cyclic voltammetry ,Biosensor - Abstract
A molecularly imprinted polymer (MIP)-based impedimetric biosensor was developed for the electrochemical analysis of low-weight biological molecules. Synthetic polymeric matrices with specific and selective recognition sites, which are complementary to the shapes and sizes of the functional groups of analytes, can be prepared using the molecular imprinting method. In this study, a small molecule, tris(hydroxymethyl)aminomethane (TRIS), was used to coat a graphite pencil tip with a TRIS-containing polyacrylamide gel to fabricate a working electrode. The electrode modification and performance were evaluated using cyclic voltammetry and electrochemical impedance spectroscopy. The electrochemical properties of the modified electrodes were observed using an electrochemical cell comprising a Ag/AgCl reference electrode, a Pt wire as the counter electrode, and a pencil graphite tip as the working electrode using a redox-phosphate buffer solution with different concentrations of TRIS and Ethylenediaminetetraacetic acid (EDTA). The I–V and impedance performance of the chemically modified graphite pencil-tip electrodes exhibited decreased conductance and increased impedance correlating with the increase in TRIS concentration. Thus, MIP-based small-molecule biosensor prototypes can be promising economical replacements over other expensive sensors.
- Published
- 2018
7. Robot yardımlı radikal prostatektomi alanındaki bilimsel üretkenliğin değerlendirilmesi
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Fuat Ernis Su and Enver Özdemir
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- 2015
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8. Torsion of a Left Atrophic Ectopic Testis
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Mehmet Yazıcı, Şiir Yıldırım, Mehmet Nuri Güneş, Hüseyin Koçan, Erhan Erdoğan, Enver Özdemir, and Erçin Altıok
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Ectopic testis ,business.industry ,medicine ,Torsion (mechanics) ,Anatomy ,medicine.disease ,business - Published
- 2016
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9. The Magic of Superposition: A Survey on Simultaneous Transmission Based Wireless Systems
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Ufuk Altun, Gunes Karabulut Kurt, and Enver Ozdemir
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Simultaneous transmission ,superposition ,interference ,wireless multiple access ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
In conventional communication systems, any interference between two communicating points is regarded as unwanted noise since it distorts the received signals. On the other hand, allowing simultaneous transmission and intentionally accepting the superposition of signals and even benefiting from it have been considered for a range of wireless applications. As prominent examples, non-orthogonal multiple access (NOMA), joint source-channel coding, and the computation codes are designed to exploit this scenario. They also inspired many other fundamental works from network coding to consensus algorithms. Especially, federated learning is an emerging technology that can be applied to distributed machine learning networks by allowing simultaneous transmission. Although various simultaneous transmission applications exist independently in the literature, their main contributions are all based on the same principle; the superposition property. In this survey, we aim to emphasize the connections between these studies and provide a guide for the readers on the wireless communication techniques that benefit from the superposition of signals. We classify the existing literature depending on their purpose and application area and present their contributions. The survey shows that simultaneous transmission can bring scalability, security, low-latency, low-complexity and energy efficiency for certain distributed wireless scenarios which are inevitable with the emerging wireless technologies.
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- 2022
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10. Secure E-Commerce Scheme
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Sena Efsun Cebeci, Kubra Nari, and Enver Ozdemir
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E-commerce security ,security protocol ,algorithm development ,symmetric key cryptography ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
E-commerce security has recently been an emerging topic due to the escalation in credit card fraud and stolen user accounts. In general, the security bridge and privacy leakage occur on the side of e-commerce companies due to various factors such as flaws in the design of their storage systems. The stored information of users increases the risk on privacy bridge and to remedy such risks e-commerce companies are forced to make costly investments. The security threats also enforce the development of robust security protocols and methods in digital commerce systems. The current protocols and methods generally bring extra communication and computation costs to all parties involving in the e-commerce system and the security risk on the side of e-commerce companies still remains. In this paper, we propose a Secure E-commerce Scheme (SES) which alleviates the security threats on the side of e-commerce companies and reduces communication costs for all parties. The proposed secure e-commerce protocol, SES, is implemented, analyzed and compared to two well-known schemes; Secure Electronic Transaction (SET) and 3D Secure.
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- 2022
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11. Surface wave investigation of different size rectangular patch HIGP and low profile antenna interaction
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Emin Unal, Enver Özdemir, and Muharrem Karaaslan
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Materials science ,business.industry ,Metamaterial ,law.invention ,Dipole ,Microstrip antenna ,High impedance ,Optics ,law ,Surface wave ,Return loss ,Dipole antenna ,business ,Ground plane - Abstract
Multi-scale rectangular element mushroom structure high impedance ground plane (HIGP) designed to exhibit larger band gap frequency range to cover greater bandwidth for low profile antenna design. The HIGP's are composed of three different dimensioned rectangular patch mushroom elements for different resonance frequency realization. The characterizations of the three scaled HIGP varying all the dimensions are observed between 1–20 GHz frequency ranges. The effect of the multi-scale HIGP to the return loss of dipole antenna radiates at 8,5 GHz for free space investigated depending on the dipole direction and position.
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- 2010
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12. İnfertil Erkek ve Vajinitli Kadın Hastalarda Trichomonas vaginalis, Gardnarella vaginalis ve Candida ssp. Sıklığı
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Mustafa Kaplan, Ahmet Erensoy, Enver Özdemir, and Neslihan Keleştemur
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General Veterinary ,business.industry ,Medicine ,business - Published
- 2009
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13. A Higher-Level Security Scheme for Key Access on Cloud Computing
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Baris Celiktas, Ibrahim Celikbilek, and Enver Ozdemir
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Cloud security ,hierarchical ,interpolation ,key access ,key assignment ,secret sharing ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
In this work, we construct a key access management scheme that seamlessly transitions any hierarchical-like access policy to the digital medium. The proposed scheme allows any public cloud system to be used as a private cloud. We consider the data owner an entity consisting of several organization units. We provide a secure method for each user of this entity to access the public cloud from both inside and outside the company’s network. The idea of our key access control scheme, which is based on Shamir’s secret sharing algorithm and polynomial interpolation method, is suitable especially for hierarchical organizational structures. It offers a secure, flexible, and hierarchical key access mechanism for organizations utilizing mission-critical data. It also minimizes concerns about moving mission-critical data to the public cloud and ensures that only users with sufficient approvals from the same or higher privileged users can access the key by making use of the topological ordering of a directed graph, including self-loop. Main overheads such as public and private storage needs are reduced to a tolerable level, and the key derivation is computationally efficient. From a security perspective, our scheme is both resistant to collaboration attacks and provides key indistinguishability security. Since the key does not need to be held anywhere, the problem of a data breach based on key disclosure risk is also eliminated.
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- 2021
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14. A Key Verification Protocol for Quantum Key Distribution
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Gunes Karabulut Kurt, Enver Ozdemir, Neslihan Aysen Ozkirisci, and Ozan Alp Topal
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Key verification ,polynomial interpolation ,quantum key distribution ,secret sharing ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Sharing a secret key between two physically separated nodes, Alice and Bob, is possible through the use of quantum key distribution (QKD) techniques. In the presence of an eavesdropper, Alice's key may not be identical with Bob's key, due to the characteristics of a quantum channel. To obtain identical keys at Alice and Bob, we propose a block-based key verification protocol that relies on Newton's polynomial interpolation. As the nodes solely share random numbers and indices of the removed blocks, no information is revealed about the secret message, at a cost of higher computational complexity. The error propagation through the key verification process is prevented by the characteristics of the proposed approach.
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- 2019
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15. Association of Serum YKL-40 Level with Tumor Burden and Metastatic Stage of Prostate Cancer
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Enver Ozdemir, Tarık Cicek, and Mehmet Onur Kaya
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prostatic neoplasms ,tumor marker ,tumor burden ,prostate-specific antigen ,Diseases of the genitourinary system. Urology ,RC870-923 - Abstract
PURPOSE: To investigate the relationship between serum level of YKL-40 and Gleason score, grade and stage of the disease, and for the first time, with tumor burden in patients with prostate cancer (PCa). MATERIALS AND METHODS: Serum levels of YKL-40 and prostate-specific antigen were measured in 34 men (mean age: 66 years) with newly diagnosed and untreated PCa, in 34 men (mean age: 65 years) with biopsy proven benign prostatic hyperplasia, and in 29 healthy young men (mean age: 24 years). RESULTS: Serum YKL-40 concentration in men with PCa and benign prostatic hyperplasia, and in controls were 165.67 ± 107.84 ng/mL, 137.38 ± 82.04 ng/mL, and 69.69 ± 18.46 ng/mL, respectively. Serum level of YKL-40 was correlated with tumor burden in 30.4% of the patients with PCa (P = .04). A cut-off serum YKL-40 value of 92.696 ng/mL produced 70.6% sensitivity and 93.1% specificity. Elevated serum level of YKL-40 was strongly associated only with metastatic stage of the PCa. No association was observed between elevated level of YKL-40 and Gleason score groups or Gleason grade. CONCLUSION: Our results suggest that elevated serum level of YKL-40 may be a useful indicator of tumor burden and metastatic stage of PCa. Further studies are warranted to better elucidate the meaning of YKL-40 in tumor burden and invasiveness.
- Published
- 2012
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