9 results on '"Ararat K"'
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2. NOISE PROTECTION OF SPACE-BASED SYNTHETIC APERTURE RADAR BASED ON DIGITAL AFAR
- Author
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Ararat K. Grigoryan and Vasily N. Yudin
- Subjects
Synthetic aperture radar ,Noise ,Computer science ,Acoustics ,Space (mathematics) - Abstract
The article deals with General questions about the definition of parameters, the calculation of which is necessary for choosing a method for organizing interference protection of a synthetic aperture radar (RSA), analyzes and notes the features of the construction and functioning of the RSA. The features of noise protection on radars of various companies are considered: COSMO-SkyMed -4 (Constellation of Small Satellites for Mediterranean basin Observation) X-band (made in Italy), TerraSAR-X/TanDEM-X (Germany), “Kasatka-R” (Russia). The subject of the study is a synthetic aperture radar, which is a coherent radar system that uses the flight path of the platform to simulate extremely large obstacles or objects electronically, and which generates high-resolution remote sensing images. Over time, individual transmit / receive cycles are completed, and data for each cycle is stored electronically. When the signal processing uses the amplitude and phase of the received signals in successive pulses from elements of a synthetic aperture. After a set number of cycles, the stored data is re-combined (taking into account the Doppler Effect inherent in different transmitters for the target geometry in each subsequent cycle) to create a high-resolution image of the terrain over which the flight is performed. The analysis of the RSA parameters that affect the radar noise immunity is performed. Objective: to analyze the interference protection of a space-based synthetic aperture radar based on digital AFAR. It is necessary to identify the type of interference that has an effective interfering effect on the protected object and determine their degree of impact depending on the parameters of the interference source. Noise immunity refers to the ability of a radio system to resist interference. Radars from various manufacturers have differential methods for improving noise immunity. The calculation of the radar range is given for the purpose of detailed consideration of the parameters of the maximum range of radio interference. The paper focuses on the main radar interference and options for improving noise immunity for this type of radar. Methodology: analysis of existing literature, analysis of technical characteristics of radars from various manufacturers, modeling of possible types of interference, deduction, induction, comparison of used radars with synthesized aperture, formalization.
- Published
- 2021
3. 46 - Double trouble: cytomegalovirus (CMV) underlying streptococcus pneumoniae otitis media in a neonate
- Author
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Tilly, CM, Ararat, K, Shah, S, Krellwitz, L, and McKee, S
- Published
- 2024
- Full Text
- View/download PDF
4. SMARCA4-deficient central nervous system metastases: A case series and systematic review.
- Author
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Morris M, Ararat K, Cutshall H, Gokden M, Rodriguez A, Rooper L, Lindberg M, and Nix JS
- Subjects
- Humans, Middle Aged, Female, Male, Aged, Lung Neoplasms pathology, Lung Neoplasms genetics, Lung Neoplasms secondary, Adult, Transcription Factors genetics, Transcription Factors deficiency, DNA Helicases deficiency, DNA Helicases genetics, Nuclear Proteins genetics, Nuclear Proteins deficiency, Central Nervous System Neoplasms secondary, Central Nervous System Neoplasms pathology, Central Nervous System Neoplasms genetics
- Abstract
SMARCA4 alterations can be encountered in a variety of human neoplasms, and metastases to the central nervous system (CNS) are rare, offering a challenge to neuropathologists despite not representing a distinct diagnostic entity. To better understand the clinical and histologic presentation of such neoplasms, we report an observational case series and systematic review of 178 unique articles that yielded 15 published cases and 7 cases from institutional files. In the systematic review, the median age was 58 years, the male-to-female ratio was 2:1, and the most common diagnosis was lung adenocarcinoma; all CNS metastases were discovered within 1 year of presentation. In the case series, the median age was 58 years, the male-to-female ratio was 6:1, and all known metastases originated from the lung. Most patients had a smoking history and died of disease. GATA-3 positivity was seen in most case series examples. Concurrent TP53 mutations (83.3%) and a high tumor mutation rate (60%) were common. To our knowledge, this is the only case series and systematic review in the English literature aimed at assessing SMARCA4-altered metastases in the CNS and vertebral column. We highlight the challenges of neuropathologic evaluation of such tumors and provide observational evidence of early metastases, histologic appearances, and immunohistochemical findings, including previously unreported GATA-3 positivity., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Association of Neuropathologists, Inc. All rights reserved. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2024
- Full Text
- View/download PDF
5. Development and Validation of a Multiclass Model Defining Molecular Archetypes of Kidney Transplant Rejection: A Large Cohort Study of the Banff Human Organ Transplant Gene Expression Panel.
- Author
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Zhang H, Haun RS, Collin F, Cassol C, Napier JOH, Wilson J, Hassen S, Ararat K, Boils C, Messias N, Caza TN, Cossey LN, Sharma S, Ambruzs JM, Agrawal N, Shekhtman G, Tian W, Srinivas T, Qu K, Woodward RN, Larsen CP, Stone S, and Coley SM
- Subjects
- Humans, Cohort Studies, Retrospective Studies, Graft Rejection diagnosis, Graft Rejection genetics, Gene Expression, Biopsy, Kidney pathology, Kidney Transplantation adverse effects, Organ Transplantation, Kidney Diseases pathology
- Abstract
Gene expression profiling from formalin-fixed paraffin-embedded (FFPE) renal allograft biopsies is a promising approach for feasibly providing a molecular diagnosis of rejection. However, large-scale studies evaluating the performance of models using NanoString platform data to define molecular archetypes of rejection are lacking. We tested a diverse retrospective cohort of over 1400 FFPE biopsy specimens, rescored according to Banff 2019 criteria and representing 10 of 11 United Network of Organ Sharing regions, using the Banff Human Organ Transplant panel from NanoString and developed a multiclass model from the gene expression data to assign relative probabilities of 4 molecular archetypes: No Rejection, Antibody-Mediated Rejection, T Cell-Mediated Rejection, and Mixed Rejection. Using Least Absolute Shrinkage and Selection Operator regularized regression with 10-fold cross-validation fitted to 1050 biopsies in the discovery cohort and technically validated on an additional 345 biopsies, our model achieved overall accuracy of 85% in the discovery cohort and 80% in the validation cohort, with ≥75% positive predictive value for each class, except for the Mixed Rejection class in the validation cohort (positive predictive value, 53%). This study represents the technical validation of the first model built from a large and diverse sample of diagnostic FFPE biopsy specimens to define and classify molecular archetypes of histologically defined diagnoses as derived from Banff Human Organ Transplant panel gene expression profiling data., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
- Full Text
- View/download PDF
6. Systematic Performance Evaluation of a Novel Optimized Differential Localization Method for Capsule Endoscopes.
- Author
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Zeising S, Ararat K, Thalmayer A, Anzai D, Fischer G, and Kirchner J
- Subjects
- Gastrointestinal Tract, Magnetics, Capsule Endoscopes, Capsule Endoscopy
- Abstract
Capsule endoscopy is a well-established diagnostic tool for the gastrointestinal tract. However, the reliable tracking of capsule endoscopes needs further investigation. Recently, the static magnetic differential method for the localization of capsule endoscopes has shown promising results. This method was experimentally validated by investigating the difference in the measured values of the geomagnetic flux density of a representative sensor pair. In the measurements, it was revealed that misalignment of the sensors and ferromagnetic material near the sensor pair had the most significant impact on the differential approach. Besides, a systematical simulation-based study was conducted. Herein, the position and alignment of all sensors of the localization system were randomly varied. Furthermore, root-mean-squared noise was added to the sensor measurements, and the influence of nearby ferromagnetic material was evaluated. Subsequently, non-idealities were applied simultaneously on the proposed localization system, and the entire system was rotated. The proposed method was significantly better than state-of-the-art geomagnetic compensation methods for the localization of capsule endoscopes with mean position and orientation errors of approximately 2 mm and 1°, respectively.
- Published
- 2021
- Full Text
- View/download PDF
7. EndoL2H: Deep Super-Resolution for Capsule Endoscopy.
- Author
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Almalioglu Y, Bengisu Ozyoruk K, Gokce A, Incetan K, Irem Gokceler G, Ali Simsek M, Ararat K, Chen RJ, Durr NJ, Mahmood F, and Turan M
- Subjects
- Capsule Endoscopy
- Abstract
Although wireless capsule endoscopy is the preferred modality for diagnosis and assessment of small bowel diseases, the poor camera resolution is a substantial limitation for both subjective and automated diagnostics. Enhanced-resolution endoscopy has shown to improve adenoma detection rate for conventional endoscopy and is likely to do the same for capsule endoscopy. In this work, we propose and quantitatively validate a novel framework to learn a mapping from low-to-high-resolution endoscopic images. We combine conditional adversarial networks with a spatial attention block to improve the resolution by up to factors of 8× , 10× , 12× , respectively. Quantitative and qualitative studies demonstrate the superiority of EndoL2H over state-of-the-art deep super-resolution methods Deep Back-Projection Networks (DBPN), Deep Residual Channel Attention Networks (RCAN) and Super Resolution Generative Adversarial Network (SRGAN). Mean Opinion Score (MOS) tests were performed by 30 gastroenterologists qualitatively assess and confirm the clinical relevance of the approach. EndoL2H is generally applicable to any endoscopic capsule system and has the potential to improve diagnosis and better harness computational approaches for polyp detection and characterization. Our code and trained models are available at https://github.com/CapsuleEndoscope/EndoL2H.
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- 2020
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8. Case of primary Sjogren's syndrome preceded by dystonia.
- Author
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Ararat K, Berrios I, Hannoun A, and Ionete C
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- Adult, Antibodies, Antinuclear immunology, Dystonia etiology, Dystonia immunology, Female, Humans, Immunosuppressive Agents therapeutic use, Migraine Disorders diagnosis, Migraine Disorders etiology, Migraine Disorders immunology, Neuralgia diagnosis, Neuralgia etiology, Neuralgia immunology, Primary Dysautonomias diagnosis, Primary Dysautonomias etiology, Primary Dysautonomias immunology, Raynaud Disease diagnosis, Raynaud Disease etiology, Raynaud Disease immunology, Salivary Glands, Minor pathology, Sensation Disorders diagnosis, Sensation Disorders etiology, Sensation Disorders immunology, Sjogren's Syndrome complications, Sjogren's Syndrome drug therapy, Sjogren's Syndrome immunology, Syncope diagnosis, Syncope etiology, Syncope immunology, Urinary Bladder, Neurogenic diagnosis, Urinary Bladder, Neurogenic etiology, Urinary Bladder, Neurogenic immunology, Dystonia diagnosis, Sjogren's Syndrome diagnosis
- Abstract
There are only six cases in literature that describe development of dystonia with Sjogren's syndrome (SS). We describe a case of a 43-year-old woman who presented with symptoms including movement disorder, sensory neurogenic bladder, sensory loss and neuropathic pain, migraine like headaches, musculoskeletal pain, Raynaud's phenomenon and dysautonomia. Symptoms started in 2000, with weakness that progressed to dystonia in 2003. Diagnostic work-up was inconclusive with negative inflammatory serologies, cerebrospinal fluid and MRI for many years. After patient developed sicca syndrome with dry eyes and mouth in 2009, her rheumatoid factor titre was elevated (550 IU/mL), erythrocyte sedimentation rate, anti-Sjogrens syndrome-related antigen A (anti-Ro/SSA) and anti-SSB/La: anti-Sjogrens syndrome-related antigen B (anti-La/SSB) became positive. Lip biopsy confirmed diagnosis of SS. She was diagnosed with primary SS with neurological involvement. Her symptoms responded well to intravenous methylprednisolone. Symptoms stabilised with trials of immune-suppressive therapy. This is a case that demonstrates the delay of diagnosing SS with preceding unique neurological association., Competing Interests: Competing interests: CI: Biogen Idec and Genzyme. She has received compensations for consulting and advisory boards from Genzyme and TEVA. IB has received compensation for consulting in advisory board from Genzyme., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)
- Published
- 2018
- Full Text
- View/download PDF
9. Eidinemacheilus proudlovei, a new subterranean loach from Iraqi Kurdistan (Teleostei; Nemacheilidae).
- Author
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Freyhof J, Abdullah YS, Ararat K, Ibrahim H, and Geiger MF
- Subjects
- Animals, Caves, Cypriniformes genetics, DNA Barcoding, Taxonomic, Iraq, Species Specificity, Cypriniformes anatomy & histology, Cypriniformes classification
- Abstract
Eidinemacheilus proudlovei, new species, is described from subterranean waters in the Little Zab River drainage in Iraqi Kurdistan. After the discovery of E. smithi in 1976, E. proudlovei is the second troglomorphic nemacheilid loach found in the Middle East and the second species placed in Eidinemacheilus. Eidinemacheilus proudlovei is distinguished from E. smithi by having 8+8 or 8+7 branched caudal-fin rays, no adipose keel on the caudal peduncle, enlarged jaws and a fully developed head canal system. It furthers differs substantially in its DNA barcode (>8% K2P distance) from all other nemacheilid loaches in the Middle East, Europe and Western India.
- Published
- 2016
- Full Text
- View/download PDF
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