1.Biaxial flexural strength and phase transformation of Ce-TZP/Al2O3 and Y-TZP core materials after thermocycling and mechanical loading.
Merve BANKOGLU GUNGOR ; Handan YILMAZ ; Cemal AYDIN ; Secil KARAKOCA NEMLI ; Bilge TURHAN BAL ; Tulay TIRAS
The Journal of Advanced Prosthodontics 2014;6(3):224-232
PURPOSE: The purpose of the present study was to evaluate the effect of thermocycling and mechanical loading on the biaxial flexural strength and the phase transformation of one Ce-TZP/Al2O3 and two Y-TZP core materials. MATERIALS AND METHODS: Thirty disc-shaped specimens were obtained from each material. The specimens were randomly divided into three groups (control, thermocycled, and mechanically loaded). Thermocycling was subjected in distilled water for 10000 cycles. Mechanical loading was subjected with 200 N loads at a frequency of 2 Hz for 100000 times. The mean biaxial flexural strength and phase transformation of the specimens were tested. The Weibull modulus, characteristic strength, 10%, 5% and 1% probabilities of failure were calculated using the biaxial flexural strength data. RESULTS: The characteristic strengths of Ce-TZP/Al2O3 specimens were significantly higher in all groups compared with the other tested materials (P<.001). Statistical results of X-ray diffraction showed that thermocycling and mechanical loading did not affect the monoclinic phase content of the materials. According to Raman spectroscopy results, at the same point and the same material, mechanical loading significantly affected the phase fraction of all materials (P<.05). CONCLUSION: It was concluded that thermocycling and mechanical loading did not show negative effect on the mean biaxial strength of the tested materials.
Spectrum Analysis, Raman
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Water
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X-Ray Diffraction
2.Asymmetrical Dimethylarginine Levels in Hepatitis B Virus-Positive Patients.
Faruk KARAKECILI ; Aytekin CIKMAN ; Merve AYDIN ; Baris GULHAN
Annals of Laboratory Medicine 2018;38(5):446-449
BACKGROUND: High asymmetrical dimethylarginine (ADMA) levels have been associated with endothelial dysfunction and contribute to the development of several diseases. However, data on the relationship between hepatitis B virus (HBV) and ADMA are limited. The aim of our study was to explore the relationship between ADMA and HBV by comparing the ADMA levels in patients with chronic active hepatitis B (CHB), inactive HBV carriers (carriers), and healthy volunteers (controls). METHODS: The participants were divided into three groups: 90 patients with CHB, 90 HBV carriers, and 90 controls. Serum ADMA levels were quantified using an ELISA kit (Cusabio, Wuhan, China). The data were analyzed using an ANOVA or the Kruskal-Wallis test as appropriate, with P<0.05 considered significant. RESULTS: Serum ADMA levels were significantly higher in patients with CHB (228.35±91.10 ng/mL) than in HBV carriers (207.80±75.80 ng/mL) and controls (207.61±89.10 ng/mL) (P=0.049). The clinical scores of the patients were positively correlated with ADMA levels. CONCLUSIONS: The elevated serum ADMA levels in patients with CHB confirm that HBV plays a role in vasculitis. Further investigation of the mechanisms contributing to the high levels of ADMA in CHB may contribute toward development of new treatment modalities.
Enzyme-Linked Immunosorbent Assay
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Healthy Volunteers
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Hepatitis B virus
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Hepatitis B*
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Hepatitis*
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Hepatitis, Chronic
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Humans
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Vasculitis
3. Molecular characterization and subtyping of Blastocystis in urticarial patients in Turkey
Merve AYDIN ; Aytekin CIKMAN ; Baris GULHAN ; Murat KARA ; Merve AYDIN ; Mustafa YAZICI ; Mehtap DEMIRKAZIK ; Ismail KOLTAS ; Tugce DURAN ; Tugce DURAN ; Aysun YILMAZ
Asian Pacific Journal of Tropical Medicine 2019;12(10):450-456
Objective: To investigate Blastocystis' etiologic role and association with gastrointestinal symptomatology in acute and chronic urticaria patients and to identify Blastocystis subtypes responsible for urticaria. Methods: The study included urticaria patients and healthy individuals that presented to our polyclinic between June 2015 and May 2017. The participants were assigned into Group I (137 patients), subdivided into acute (72) and chronic urticaria patients (65), and Group ? (129 control individuals). Blastocystis presence was investigated by native-Lugol examination, trichrome staining, PCR using sequence tagged site primers, and DNA sequencing analysis. The phylogenetic tree was constructed. Results: The native-Lugol and trichrome staining methods revealed that 16 patients (16/133, 12.0%) had Blastocystis-positive stool samples, of which seven samples (7/133, 5.3%) belonged acute and nine (9/133, 6.8%) to chronic urticaria patients. Concerning Blastocystis subtypes, of the acute urticaria patients, three had subtype 1 (ST1), one had ST2, and three had ST3. Of the chronic urticaria patients, one had ST1 and eight had ST3. Blastocystis positivity was detected in two control individuals (2/123, 1.6%), both being ST3. All subtypes identified by PCR were confirmed by the sequencing analysis. The acute and chronic urticaria groups showed no statistically significant differences for Blastocystis positivity (P=0.60) and subtype distribution (P=0.15). A statistically significant difference was found between the urticaria patients and the controls for Blastocystis positivity (P<0.01), but not for subtype distribution (P=0.67) or for Blastocystis presence and gastrointestinal complaints. Conclusions: This study on Blastocystis subtype distribution among Turkish urticaria patients showed results consistent with the literature. It was concluded that Blastocystis should be kept in mind in patients with urticaria.
4. Outcome of patients with severe COVID-19 pneumonia treated with high-dose corticosteroid pulse therapy: A retrospective study
Hanife Nur KARAKOC ; Safiye Nur OZCAN ; Aysun AKSOY ; Merve AYDIN ; Gulcin ZENGIN ; Hacer Aksit YASAR
Asian Pacific Journal of Tropical Medicine 2022;15(4):161-170
Objective: To assess the effectiveness of high-dose corticosteroid pulse therapy and evaluate possible factors associated with 28-day mortality in hospitalised patients with severe COVID-19 pneumonia. Methods: We conducted a single-centre retrospective cohort study on hospitalised patients with clinical, epidemiological, and/or radiologically confirmed and suspected COVID-19 at Bitlis Tatvan State Hospital in Turkey between December 1, 2020 and June 1, 2021. All data of the study participants were recorded, and all patients received intravenous high-dose corticosteroid pulse therapy. The Ordinal Scale for Clinical Improvement (OSCI), Charlson Comorbidity Index and Total Severity Score were calculated. Univariate and multivariate Cox regression models were performed to evaluate the clinical and laboratory parameters that may affect the 28-day mortality. Results: A total of 126 patients were included in the analysis. The 28-day mortality rate of the patients was 22.2%. Laboratory and clinical improvement were observed in 77.8% (98/126) of patients after high-dose corticosteroid pulse therapy. There was a statistically significant difference between the survivors and non-survivors in terms of age, platelet count, neutrophil/lymphocyte ratio, and OSCI, Charlson Comorbidity Index, and Total Severity Score (P<0.001). Multivariate Cox regression analysis revealed that age [HR 1.047 (95% CI 1.01-1.08)], use of prophylactic anticoagulation [HR 0.838 (95% CI 0.79-0.89)], and bacterial co-infection [HR 3.966 (95% CI 1.40-11.21)] were significant determinants of mortality. Early C-reactive protein (CRP) response, decreased oxygen requirement, and improving respiratory rate/OSCI scores after administration of high-dose corticosteroid pulse therapy could contribute to clinical improvement. Conclusions: CRP response, needed oxygen and OSCI scores can be used as prognostic factors to select patients who will benefit from high-dose corticosteroid pulse therapy.