Yazar "Mert A." seçeneğine göre listele
Listeleniyor 1 - 16 / 16
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Assessment of the Topographic Relationship Between the Maxillary Sinus and Maxillary Posterior Teeth Using Cone Beam Computed Tomography; [Maksiller Posterior Dişler ile Maksiller Sinüs Arasındaki Topografik İlişkinin Konik Işınlı Bilgisayarlı Tomografi Kullanılarak Değerlendirilmesi](AVES, 2024) Gürhan C.; Şener E.; Mert A.; Baksi B.G.Objective: The aim was to identify the distance between the apices of maxillary posterior teeth and maxillary sinus (MS) floor as well as the thickness of the bone between the root and the alveolar cortical plate. Methods: The cone-beam computed tomography scans of 74 patients were evaluated retrospec-tively. Topographic measurements of the surrounding bone at the apex of all premolar and molar maxillary teeth were performed in 2 different planes (vertical and horizontal). A 1-way analysis of variance was used to determine the differences in linear measurements between each root for all tooth types and genders. Results: The mean vertical distance to the MS floor was significantly high for first premolar roots and the lowest mean vertical distance was measured for mesio-buccal roots of second molars (P < 0.05). In contrast, the lowest buccal bone thickness was found for the first premolar, whereas the highest buccal thickness was measured for the mesiobuccal roots of the second molars (P < .05). When gender groups were evaluated separately, it was found that the vertical distance between the apices of second premolar teeth and the MS floor was significantly higher in females (P < .05). Moreover, the mesiobuccal and palatal horizontal measurements of second molars were higher in females (P < .05). Conclusion: It is important to have knowledge about the linear measurements and morphologi-cal features of the maxillary alveolar bone in order to carry out successfull dental practices The obtained results were expected to be beneficial for clinicians to reduce the complication, espe-cially in dental procedures involving maxillary molar region. © 2024, AVES. All rights reserved.Öğe Diagnostic accuracy of proximal enamel subsurface demineralization and its relationship with calcium loss and lesion depth(2012) Önem E.; Baksi B.G.; Şen B.H.; Sögüt Ö.; Mert A.Objective: The aim of this study was to determine the relationship between the amount of calcium loss, lesion depth, and the accuracy of storage phosphor plate (SPP) and film radiographs for the detection of artificial proximal demineralization. Methods: Standard enamel windows of extracted premolars were exposed to a demineralizing solution for 60 h, 80h, 100 h and 120 h. Solutions were analysed for calcium concentration by atomic absorption spectrometer and the lesion depths were calculated by a specific formula. All teeth were radiographed with SPPs and F-speed films before and after acid application. Images were evaluated by five observers. Stereomicroscopic and scanning electron microscopic (SEM) observations were carried out to visualize enamel surfaces after acid exposure. Receiver operating characteristic analysis was used for diagnostic accuracy (A z). A zs were compared with factorial analysis of variance and t-tests. The relationship between A zs and lesion depths was determined with Pearson's correlation test. Results: Strong positive correlation was found between A zs of both radiographic methods and lesion depths. No difference was found between the A zs of two radiographic systems for any of the demineralization durations (p > 0.05). Pair-wise comparisons revealed no significant difference in Azs of SPPs (p > 0.05), while significant differences were obtained for the A zs of films for different demineralization periods (p < 0.05). Stereomicroscopic and SEM observations confirmed demineralizations from superficial to deeper layers of enamel. Conclusion: Subsurface enamel demineralization was not accurately detectable with either storage phosphor plates or F-speed films. The amount of calcium loss and the depth of demineralization have a strong relationship with diagnostic accuracy with a significant effect particularly on F-speed films. © 2012 The British Institute of Radiology.Öğe Does a combination of two radiographs increase accuracy in detecting acid-induced periapical lesions and does it approach the accuracy of cone-beam computed tomography scanning?(2012) Sogur E.; Gröndahl H.-G.; Baks B.G.; Mert A.Introduction: The purpose of this study was to determine whether the use of a combination of 2 images (storage phosphor plates [SPPs] and F-speed films [Eastman Kodak, Rochester, NY]) with a 10° difference in horizontal beam angulation resulted in better detectability of chemically created periapical defects than when only 1 image was used and whether a detectability as good as that achieved by limited cone-beam computed tomography (LCBCT) scanning could be achieved. Methods: Lesions were created by 1, 1.5, and 2 hours of acid application apical to extracted teeth in jaw specimens. After repositioning, teeth were radiographed with Accu-I-Tomo LCBCT, Digora Optime SPP system, and F-speed films. The SPPs and films were exposed at 0° and 10° horizontal angulations. The diagnostic accuracy (Az) was compared using 2-way analysis of variance; pair-wise comparisons were performed using the post hoc t test. Kappa was used to measure interobserver agreement. Results: A combination of 2 exposures with a 10° difference in horizontal angulation caused an increase, although not statistically significant, in the accuracy of both films and SPPs for all acid durations (P >.05) compared with when only 1 exposure was used. The accuracy did not approach that of LCBCT. Conclusions: Using a combination of 2 exposures instead of 1 did not significantly increase the accuracy in detecting acid-induced lesions at the apices of single-rooted premolars. The accuracy of LCBCT was superior. Copyright © 2012 American Association of Endodontists.Öğe The effect of delayed scanning of storage phosphor plates on occlusal caries detection(2012) Sogur E.; Baksi B.G.; Mert A.Objective: The aim of this study was to determine (1) the effect of various scan delays on pixel intensity measurements and (2) the diagnostic accuracy of occlusal caries detection. Methods: 72 non-cavitated extracted human permanent molar teeth with sound and carious occlusal surfaces were radiographed using the DIGORA ® storage phosphor plates (SPPs) (Soredex Corporation, Helsinki, Finland). Plates were scanned immediately and 10 min, 30 min, 60 min and 120 min after exposure. Three different plates were used for each scan delay. An aluminium (Al) wedge was used to evaluate the change in mean grey values (MGVs) for scan delays. Diagnostic accuracy for occlusal caries detection was performed by scoring all the digital images. The true presence of caries was determined by stereomicroscopy. Comparison of MGVs of the Al wedge for immediate and delayed scans was made using repeated measures analysis of variance (ANOVA) and Tukey-Kramer tests. The accuracy was expressed as the area under the receiver operating characteristics curves (A z). A zs were compared using two-way ANOVA and t-tests. Kappa was used to measure inter and intraobserver agreement. Results: The mean A zs of immediately scanned plates were higher than the A zs of plates scanned with four different delays (p < 0.05). The A z of immediately scanned images was significantly higher than the A zs of images with 60 min and 120 min scan delays (p < 0.05) but not for 10min and 30min delays (p > 0.05). MGVs of immediately scanned plates were significantly higher than the plates scanned with four different delays (p < 0.05). Agreement decreased with increasing scan delays. Conclusion: Scanning of DIGORA SPPs should not be delayed beyond 30min for accurate occlusal caries diagnosis. © 2012 The British Institute of Radiology.Öğe Fuzzy disaster relief planning with credibility measures(Vilnius Gediminas Technical University, 2010) Mert A.; Adivar B.O.We propose a disaster relief planning model that can handle unclear information while maximizing the credibility of the relief organizations in the most cost efficient way. Considering the uncertainty and incompleteness of the disaster data, we propose a novel non-linear fuzzy credibility measure based on the timely arrival of the relief items. By using fuzzy linear programming, theoretical performance of the relief effort is optimized for the desired level of credibility and more effective asset utilization is provided. The applicability of the model is justified with real data to demonstrate its use for organizations to establish accountable and more credible status in the eyes of donor countries and vulnerable communities. © Izmir University of Economics, Turkey, 2010.Öğe Hemophagocytic lymphohistiocytosis in adults: Low incidence of primary neoplasm as a trigger in a case series from Turkey(Universita Cattolica del Sacro Cuore, 2018) Arslan F.; Alp S.; Büyükasık Y.; Ozkan M.C.; Şahin F.; Basaran S.; Cagatay A.A.; Eraksoy Ö.H.; Aksu K.; Ertunç B.; Korten V.; Ceylan B.; Mert A.Hemophagocytic Lymphohistiocytosis (HLH) is an indicator of an exaggerated immune response and eventually adverse outcomes. This study aimed to investigate the clinical and laboratory features and outcomes of patients with HLH. The medical records of 26 HLH adult patients (? 16 years of age) were retrospectively analyzed. Gender, age, the duration of fever, time to diagnosis, etiology and laboratory data were extracted from the records. The mean age was 38 ± 18 years, and 15 (58%) patients were female. A total of nine cases had infectious diseases; four cases had rheumatologic diseases, three cases had hematological malignancies while nine cases could not have a definitive diagnosis. The median time to detection of HLH was 20 days (IQR: 8-30 d). Of the 25 patients, 11 (44%) died. The erythrocyte sedimentation rates of the surviving and non-surviving patients were 39 ± 22 mm/h and 15 ± 13 mm/h, respectively. When a long-lasting fever is complicated by bicytopenia or pancytopenia (especially), clinicians should promptly consider the possibility of HLH syndrome to improve patients' prognosis. © 2018 Slovensko Kemijsko Drustvo. All Rights Reserved.Öğe Interferon-?2b induction treatment with or without ribavirin in chronic hepatitis C: A multicenter, randomized, controlled trial(2003) Senturk H.; Ersoz G.; Ozaras R.; Kaymakoglu S.; Bozkaya H.; Akdogan M.; Mert A.; Bozdayi M.; Tabak F.; Yenice N.; Ozbay G.We aimed to compare the efficacy of interferon-?2b (IFN) induction treatment in combination with ribavirin to IFN induction alone in chronic hepatitis C. In total, 125 patients (66 male, 59 female, mean age: 48 ± 9, range: 21-70) were enrolled and randomized into two arms: In the first, patients received 5 MU/day of IFN for 4 weeks followed by 3 MU/day for the next 4 weeks. Treatment was continued with 3 MU three times a week IFN for an additional 40 weeks. Ribavirin was administered 1000-1200 mg/day according to the body weight for the entire 48-week period. In the second arm, patients received placebo in addition to IFN. Fifty-nine patients were placed in the ribavirin arm and 66 in placebo arm. All patients were genotype 1. At week 48, 24/66 (36%) from the placebo and 31/59 (52%) from the ribavirin group responded (P > 0.05). However, during the 24-week untreated follow-up period, 13/24 (54%) from the placebo, and 8/31 (26%) from the ribavirin group relapsed (P = 0.002.), resulting in a sustained virologic response (SVR) rate of 17% in the placebo and 39% in the ribavirin group (P = 0.005.) In conclusion, IFN induction treatment in combination with ribavirin is superior to IFN induction treatment alone in genotype 1 patients, and the SVR rate of 39% is encouraging.Öğe A learning algorithm for level sets weights in weighted level-based averaging method(2005) Nasibov E.N.; Baskan O.; Mert A.The method which we call the Weighted Averaging Based on Levels (WABL) can be used to calculate the average representative of a fuzzy number. It utilizes weight coefficients for the level sets as well as the sides of a fuzzy number. We have developed an algorithm to obtain these coefficients. The most remarkable feature of this algorithm is that it makes use of the decision maker's (DM) aggregation strategy. © 2005 Springer Science+Business Media, Inc.Öğe Miliary tuberculosis(Lippincott Williams and Wilkins, 2017) Mert A.; Arslan F.; Kuyucu T.; Koç E.N.; Yilmaz M.; Turan D.; Altin S.; Pehlivanoglu F.; Sengoz G.; Yildiz D.; Dokmetas I.; Komur S.; Kurtaran B.; Demirdal T.; Erdem H.A.; Sipahi O.R.; Batirel A.; Parlak E.; Tekin R.; Tunçcan Ö.G.; Balkan I.I.; Hayran O.; Ceylan B.The aim of this study was to determine the clinical features, and outcome of the patients with miliary tuberculosis (TB). We retrospectively evaluated 263 patients (142 male, 121 female, mean age: 44 years, range: 16-89 years) with miliary TB. Criteria for the diagnosis of miliary TB were at least one of the followings in the presence of clinical presentation suggestive of miliary TB such as prolonged fever, night sweats, anorexia, weight loss: Radiologic criterion and pathological criterion and/or microbiological criterion; pathological criterion and/or microbiological criterion. The miliary pattern was seen in 88% of the patients. Predisposing factors were found in 41% of the patients. Most frequent clinical features and laboratory findings were fever (100%), fatigue (91%), anorexia (85%), weight loss (66%), hepatomegaly (20%), splenomegaly (19%), choroid tubercules (8%), anemia (86%), pancytopenia (12%), and accelerated erythrocyte sedimentation rate (89%). Tuberculin skin test was positive in 29% of cases. Fifty percent of the patients met the criteria for fever of unknown origin. Acid-fast bacilli were demonstrated in 41% of patients (81/195), and cultures for Mycobacterium tuberculosis were positive in 51% (148/292) of tested specimens (predominantly sputum, CSF, and bronchial lavage). Blood cultures were positive in 20% (19/97). Granulomas in tissue samples of liver, lung, and bone marrow were present in 100% (21/21), 95% (18/19), and 82% (23/28), respectively. A total of 223 patients (85%) were given a quadruple anti-TB treatment. Forty-four (17%) patients died within 1 year after diagnosis established. Age, serum albumin, presence of military pattern, presence of mental changes, and hemoglobin concentration were found as independent predictors of mortality. Fever resolved within first 21 days in the majority (90%) of the cases. Miliary infiltrates on chest X-ray should raise the possibility of miliary TB especially in countries where TB is endemic. Although biopsy of the lungs and liver may have higher yield rate of organ involvement histopathologicaly, less invasive procedures including a bone marrow biopsy and blood cultures should be preferred owing to low complication rates. © 2017 the Author(s). Published by Wolters Kluwer Health, Inc.Öğe Non-HACEK Gram-negative bacillus endocarditis [Endocardite à bacilles à Gram négatif non HACEK](Elsevier Masson SAS, 2019) Ertugrul Mercan M.; Arslan F.; Ozyavuz Alp S.; Atilla A.; Seyman D.; Guliyeva G.; Kayaaslan B.; Sari S.; Mutay Suntur B.; Isik B.; Mert A.Patients and methods: Retrospective analysis of clinical data using 26 diagnosed non-HACEK Gram-negative infective endocarditis cases from nine hospitals in Turkey. Results: Mean age of patients was 53 (28–84) years, with a 23% case fatality. Nineteen (73%) of the 26 patients had at least one predisposing factor. The presence of a central venous catheter was the most common predisposing factor (7/26 patients). Pseudomonas aeruginosa (7/26 patients) and Escherichia coli (7/26 patients) were the most common pathogens. The median duration of the antibiotic therapy was 42 days (range 3–84 days). Surgical procedures were performed in 10 patients. The case fatality was similar in patients who did or did not undergo surgery (20% vs. 25%). © 2019Öğe On methods of defuzzification of parametrically represented fuzzy numbers(2007) Nasibov E.N.; Mert A.A comparative analysis of such methods of defuzzification of fuzzy numbers as WABL (Weighted Averaging Based on Levels), centroid, and mean of maxima (MOM) is presented in the study. Analytic formulas are presented for calculating the defuzzification values for parametrically represented fuzzy numbers of triangular and trapezoidal form. © 2007 Allerton Press, Inc.Öğe On the WABL defuzzification method for intuitionistic fuzzy numbers(Springer Verlag, 2020) Mert A.Intuitionistic fuzzy sets (IFSs) have been proposed by Atanassov as an extension of classical fuzzy sets (FSs) originated from an early work of Zadeh. The main advantage of the IFSs is their property to deal with the uncertainty that may be included by information. IFSs have two types of functions: membership function which is also employed to describe the conventional FSs and non-membership function. With these two functions, IFSs better describe the real status of the information. IFSs especially Intuitionistic Fuzzy Numbers (IFNs) have found application in various areas such as edge detection, image segmentation, decision making, fault-tree analysis, pattern recognition etc. Most of the applications of these areas are performed in digitalized environments. But, still our computers are designed to work with crisp numbers. That means we are still in need of well-defined defuzzification methods for IFNs. In this study, we adopted WABL (Weighted Averaging Based on Levels) defuzzification method into IFNs. We exposed some useful properties of WABL method in order to make its usage easier in application fields. © 2020, Springer Nature Switzerland AG.Öğe Plant distribution-altitude and landform relationships in karstic sinkholes of Mediterranean region of Turkey(2010) Özkan K.; Gulsoy S.; Mert A.; Ozturk M.; Muys B.The purpose of this study was to investigate the relationships between the plant distribution and the altitude-shape-size characteristics of sinkholes, and the landform characteristics inside sinkholes in the Mediterranean region of Turkey. Block kriging, Factor analysis, Cluster Analysis and Detrended Correspondence Analysis were performed. The sinkhole type and altitudinal zone were found to be the significant factors affecting the plant distribution. However, the sinkhole type was more important than the altitudinal zone. Hence, the sinkholes were first subdivided into groups according to types and then the groups were divided into subgroups according to the altitudinal zones. Consequently, 4 groups were defined; A-type sinkholes [1400-1550 m (A 1), 1550-1700 m (A2)] and B-type sinkholes [1400-1550 (B1), 1550-1700 m (B2)]. The B-type was wider vertically and shorter horizontally than A-type sinkholes. Significant differences were found between the plant distribution and slope position inside the sinkholes. Plant distribution in the lower slopes was different from that in the flats and ridges in the B1 sub-type of B-type. Plant distribution in B 2 subtype was different among the slope positions (ridge, middle slope, lower slope, and flat). Although distribution of plants is different in different parts (ridges, upper slope, middle slope, lower slope and basal flats) of A sinkhole, the differences between the parts of intermediate slope position are not significant. A high plant variability along short distances in the sinkholes was observed in the study area. That is why the site of sinkholes have a big potential for the distribution of many species. Hence, the area must be separated as strictly protected zone. © Triveni Enterprises.Öğe Prevalence of odontogenic sinus tracts in patients referred for endodontic therapy(2013) Sogur E.; Şen B.H.; Baksi B.G.; Mert A.Objectives: The primary aim of this study was to assess the prevalence, location and distribution of odontogenic sinus tracts in a population of Turkish adult patients referred for endodontic therapy. The second aim was to investigate the influence of the factors such as sex, age, systemic disease, existence and diameter of periapical radioluceny on the prevalence of the clinically detected sinus tracts among Turkish population. Materials and Methods: A total of 499 patients' records according to the demographic data and the presence of periapical radiolucency and of sinus tract were included to the present study. The location of the sinus tracts was recorded as well. Data were analyzed using Pearson chi-square and Fisher's Exact Tests (p=0.05). Results: The number of the teeth who had sinus tracts was 37 (7.4%). Sixteen of 37 teeth with sinus tracts were associated with posterior teeth (43%). No significant differences were found in the prevalence of sinus tracts between two genders (p>0.05). 40-50year age group showed the highest prevalence of sinus tracts. Conclusions: Approximately one in thirteen teeth referred for root canal treatment had a sinus tract. Fourtythree percent of sinus tracts were associated with posterior teeth with high prevalence of openings in buccal aspects of the gingiva. Therefore, practitioners should be careful while examining posterior teeth referred for endodontic treatment.Öğe Quick response model for humanitarian operations to natural disasters(2008) Ozcam B.; Mert A.A conceptual framework for North Atlantic Treaty Organization EADRCC that minimizes both the response time and transportation cost during disaster relief and humanitarian assistance operations are developed. The key achievements are to create an executable response plan within minutes upon disaster strikes, and to reduce the cost of consequence management operations to nations. The viability of the proposed approach is demonstrated by a web-based application which takes several real disaster situations into consideration.Öğe Shannon entropy-based approach for calculating values of WABL parameters(Taylor and Francis Ltd., 2020) Mert A.In the application phase of the fuzzy theory, it is an obvious advantage to have a valuable defuzzification. The defuzzification method that we deal with in this work is a flexible, adaptable and multi-purpose method. In this study, we will introduce a new concept to obtain the parameter values of the defuzzification method called WABL. The new concept is based on maximizing the entropy of the level sets weights of the method. We develop two versions for the concept. In the first one, we suppose that we have one decision-maker to supervise a fuzzy process. In the second version, we assume that we have a group of decision-makers to collectively administrate a fuzzy process. For each version, we construct a constrained optimization problem and we solve each problem analytically. The working results of the versions are demonstrated by numerical examples. © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
