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Öğe Characteristics and outcomes of hospitalised older patients with chronic kidney disease and COVID-19: A multicenter nationwide controlled study(Wiley-Hindawi, 2021) Ozturk, Savas; Turgutalp, Kenan; Arici, Mustafa; Gok, Mahmut; Islam, Mahmud; Altiparmak, Mehmet Riza; Aydin, ZekiObjective Older adults with co-morbidities have been reported to be at higher risk for adverse outcomes of coronavirus disease 2019 (COVID-19). The characteristics of COVID-19 in older patients and its clinical outcomes in different kidney disease groups are not well known. Methods Data were retrieved from a national multicentric database supported by Turkish Society of Nephrology, which consists of retrospectively collected data between 17 April 2020 and 31 December 2020. Hospitalised patients aged 18 years or older with confirmed COVID-19 diagnosis suffering from stage 3-5 chronic kidney disease (CKD) or on maintenance haemodialysis (HD) treatment were included in the database. Non-uraemic hospitalised patients with COVID-19 were also included as the control group. Results We included 879 patients [388 (44.1%) female, median age: 63 (IQR: 50-73) years]. The percentage of older patients in the CKD group was 68.8% (n = 188/273), in the HD group was 49.0% (n = 150/306) and in the control group was 30.4% (n = 70/300). Co-morbidities were higher in the CKD and HD groups. The rate of presentation with severe-critical disease was higher in the older CKD and HD groups (43.6%, 55.3% and 16.1%, respectively). Among older patients, the intensive care unit (ICU) admission rate was significantly higher in the CKD and HD groups than in the control group (38.8%, 37.3% and 15.7%, respectively). In-hospital mortality or death and/or ICU admission rates in the older group were significantly higher in the CKD (29.3% and 39.4%) and HD groups (26.7% and 30.1%) compared with the control group (8.6% and 17.1%). In the multivariate analysis, in-hospital mortality rates in CKD and HD groups were higher than control group [hazard ratio (HR): 4.33 (95% confidence interval [CI]: 1.53-12.26) and HR: 3.09 (95% CI: 1.04-9.17), respectively]. Conclusion Among older COVID-19 patients, in-hospital mortality is significantly higher in those with stage 3-5 CKD and on maintenance HD than older patients without CKD regardless of demographic characteristics, co-morbidities, clinical and laboratory data on admission.Öğe Clinical and pathologic features of primary membranous nephropathy in Turkey: a multicenter study by the Turkish Society of Nephrology Glomerular Diseases Working Group(Taylor & Francis Ltd, 2022) Yildiz, Abdulmecit; Ulu, Sena; Oruc, Aysegul; Ucar, Ali Riza; Ozturk, Savas; Alagoz, Selma; Eren, NecmiBackground We aimed to evaluate the features of primary membranous nephropathy (MNP) in Turkish people. Methods This is a retrospective analysis of patients with biopsy-proven primary MNP. We obtained the data collected between 2009 and 2019 in the primary glomerulonephritis registry of the Turkish Society of Nephrology Glomerular Diseases Study Group (TSN-GOLD). Patients with a secondary cause for MNP were excluded. Clinical, demographic, laboratory, and histopathological findings were analyzed. Results A total of 995 patients with primary MNP were included in the analyses. Males constituted the majority (58.8%). The mean age was 48.4 +/- 13.9 years. The most common presentation was the presence of nephrotic syndrome (81.7%) and sub nephrotic proteinuria (10.3%). Microscopic hematuria was detected in one-third of patients. The median estimated glomerular filtration rate (eGFR) was 100.6 mL/min/1.73 m(2) (IQR, 75.4-116.3), and median proteinuria was 6000 mg/d (IQR, 3656-9457). Serum C3 and C4 complement levels were decreased in 3.7 and 1.7% of patients, respectively. Twenty-four (2.4%) patients had glomerular crescents in their kidney biopsy samples. Basal membrane thickening was detected in 93.8% of cases under light microscopy. Mesangial proliferation and interstitial inflammation were evident in 32.8 and 55.9% of the patients, respectively. The most commonly detected depositions were IgG (93%), C3 complement (68.8%), and kappa and lambda immunoglobulin light chains (70%). Although renal functions were normal at presentation, vascular, interstitial, and glomerular findings were more prominent on biopsy in hypertensive patients. No significant effect of BMI on biopsy findings was observed. Conclusions Despite some atypical findings, the main features of primary MNP in Turkey were similar to the published literature. This is the largest MNP study to date conducted in Turkish people.Öğe COVID-19 Infection in Peritoneal Dialysis Patients: A Comparative Outcome Study with Patients on Hemodialysis and Patients without Kidney Disease(Aves, 2022) Kazancioglu, Rumeyza; Ozturk, Savas; Turgutalp, Kenan; Gursu, Meltem; Arici, Mustafa; Oruc, Aysegul; Ahbap, ElbisObjectives: There is limited data about coronavirus disease-19 (COVID-19) characteristics and results in peritoneal dialysis (PD) patients. This study aimed to investigate the characteristics and outcomes among PD patients and compare them with matched hemodialysis (HD) patients and a control group without kidney disease. Methods: We included 18 PD patients and consecutive age- and gender-matched 18 HD and 18 patients without kidney disease (control group) registered into the Turkish Society of Nephrology database including 1301 COVID-19 patients. We compared demographic, clinical, radiological, laboratory data, and outcomes namely intensive care unit (ICU) admission, mechanical ventilation, mortality, and composite outcome (death and/or ICU admission). Results: ICU admission, mechanical ventilation, and mortality rates in PD patients (27.8%, 22.2%, and 22.2%, respectively) and the HD group (16.7%, 11.1%, and 16.7%, respectively) were higher than the control group (11.1%, 11.1%, and 5.6%, respectively), but intergroup comparison did not reveal difference. A total of 11 (20.3%) patients had composite outcome (6 PD patients, 3 HD patients, and 2 patients in the control group). In Cox regression analysis, higher age and higher CRP level were related to increased risk of composite outcome. Adjusted rate of composite outcome in PD group was significantly higher than the control group (P =.050). This rate was similar in HD and control groups (P =.30). Conclusions: Combined in-hospital mortality and/or ICU admission of PD patients with COVID-19 was significantly higher than the control patients. There is a need for careful surveillance of PD patients for infection signs and prompt treatment of COVID-19.Öğe Demographic and clinical characteristics of primary glomerular diseases in Turkey(Springer, 2014) Ozturk, Savas; Sumnu, Abdullah; Seyahi, Nurhan; Gullulu, Mustafa; Sipahioglu, Murat; Artan, Serra; Bicik, ZerrinThe aim of our study was to delineate the demographic and clinical properties of primary glomerular diseases of adult population in our country in the light of global knowledge. All over the country, a total of 25 centers entered data between May 2009 and July 2012 to the database created by 'Glomerulonephritis Study Group' of Turkish Society of Nephrology. Demographic and clinical characteristics, specific diagnoses of glomerular diseases and biopsy findings recorded to the database were analyzed. Among the 1,274 patients, who had renal biopsy within the defined time period, 55 % were male and 45 % were female. The mean age was 40.8 +/- A 14.6 years. The most frequent indication for biopsy was nephrotic syndrome (57.8 %), followed by nephritic syndrome including rapidly progressive glomerulonephritis (16.6 %) and asymptomatic urinary abnormalities (10.8 %). The most frequent primary glomerular disease was membranous nephropathy (28.8 %), followed by focal segmental glomerulosclerosis (19.3 %) and IgA nephropathy (17.2 %). The presented study displayed important data about the epidemiology of primary glomerular diseases among adults in our country. The predominance of membranous nephropathy in contrast to other countries, in which the most frequent etiology is IgA nephropathy, seems to be due to differences in the indications for renal biopsy.Öğe DEMOGRAPHIC AND CLINICAL CHARACTERISTICS OF RAPIDLY PROGRESSIVE GLOMERULONEPHRITIS IN TURKEY(Oxford Univ Press, 2020) Aydin, Zeki; Turkmen, Kultigin; Dede, Fatih; Yasar, Emre; Ozturk, Savas; Aydin, Mehmet; Tatar, Erhan[Abstract Not Availabe]Öğe Demographic, clinical and laboratory characteristics of rapidly progressive glomerulonephritis in Turkey: Turkish Society of Nephrology-Glomerular Diseases (TSN-GOLD) Working Group(Springer, 2021) Aydin, Zeki; Turkmen, Kultigin; Dede, Fatih; Yasar, Emre; Ozturk, Savas; Aydin, Mehmet; Tatar, ErhanBackground In our study, diagnostic and demographic characteristics of patients diagnosed with RPGN by biopsy, clinical and laboratory findings in our country were investigated. Methods Data were obtained from the Turkish Society of Nephrology Glomerular Diseases (TSN-GOLD) Working Group database. Demographic characteristics, indications for biopsy, diagnosis of the glomerular diseases, comorbidities, laboratory and biopsy findings of all patients were recorded. According to their types, RPGN patients were classified as type 1 (anti-GBM related), type 2 (immuncomplex related) and type 3 (pauci-immune). Results Of 3875 patients, 200 patients with RPGN (mean age 47.9 +/- 16.7 years) were included in the study which constitutes 5.2% of the total glomerulonephritis database. Renal biopsy was performed in 147 (73.5%) patients due to nephritic syndrome. ANCA positivity was found in 121 (60.5%) patients. Type 1 RPGN was detected in 11 (5.5%), type 2 RPGN in 42 (21%) and type 3 RPGN in 147 (73.5%) patients. Median serum creatinine was 3.4 (1.9-5.7) mg/dl, glomerular filtration rate was 18 (10-37) ml/min/1.73m(2)and proteinuria 2100 (1229-3526) mg/day. The number of crescentic glomeruli ratio was ratio 52.7%. It was observed that urea and creatinine increased and calcium and hemoglobin decreased with increasing crescentic glomerular ratio. Conclusions Our data are generally compatible with the literature. Advanced chronic histopathological findings were prominent in the biopsy of 21 patients. Early biopsy should be performed to confirm the diagnosis of RPGN and to avoid unnecessary intensive immunosuppressive therapy. In addition to the treatments applied, detailed data, including patient and renal survival, are needed.Öğe Determinants of mortality in a large group of hemodialysis patients hospitalized for COVID-19(Bmc, 2021) Turgutalp, Kenan; Ozturk, Savas; Arici, Mustafa; Eren, Necmi; Gorgulu, Numan; Islam, Mahmut; Uzun, SamiBackground: Maintenance hemodialysis (MHD) patients are at increased risk for coronavirus disease 2019 (COVID-19). The aim of this study was to describe clinical, laboratory, and radiologic characteristics and determinants of mortality in a large group of MHD patients hospitalized for COVID-19. Methods: This multicenter, retrospective, observational study collected data from 47 nephrology clinics in Turkey. Baseline clinical, laboratory and radiological characteristics, and COVID-19 treatments during hospitalization, need for intensive care and mechanical ventilation were recorded. The main study outcome was in-hospital mortality and the determinants were analyzed by Cox regression survival analysis. Results: Of 567 MHD patients, 93 (16.3%) patients died, 134 (23.6%) patients admitted to intensive care unit (ICU) and 91 of the ones in ICU (67.9%) needed mechanical ventilation. Patients who died were older (median age, 66 [57-74] vs. 63 [52-71] years, p = 0.019), had more congestive heart failure (34.9% versus 20.7%, p = 0.004) and chronic obstructive pulmonary disease (23.6% versus 12.7%, p = 0.008) compared to the discharged patients. Most patients (89.6%) had radiological manifestations compatible with COVID-19 pulmonary involvement. Median platelet (166 x 10(3) per mm(3) versus 192 x 10(3) per mm(3), p = 0.011) and lymphocyte (800 per mm(3) versus 1000 per mm(3), p < 0.001) counts and albumin levels (median, 3.2 g/dl versus 3.5 g/dl, p = 0.001) on admission were lower in patients who died. Age (HR: 1.022 [95% CI, 1.003-1.041], p = 0.025), severe-critical disease clinical presentation at the time of diagnosis (HR: 6.223 [95% CI, 2.168-17.863], p < 0.001), presence of congestive heart failure (HR: 2.247 [95% CI, 1.228-4.111], p = 0.009), ferritin levels on admission (HR; 1.057 [95% CI, 1.006-1.111], p = 0.028), elevation of aspartate aminotransferase (AST) (HR; 3.909 [95% CI, 2.143-7.132], p < 0.001) and low platelet count (< 150 x 10(3) per mm(3)) during hospitalization (HR; 1.864 [95% CI, 1.025-3.390], p = 0.041) were risk factors for mortality. Conclusion: Hospitalized MHD patients with COVID-19 had a high mortality rate. Older age, presence of heart failure, clinical severity of the disease at presentation, ferritin level on admission, decrease in platelet count and increase in AST level during hospitalization may be used to predict the mortality risk of these patients.Öğe Impact of hospital-acquired acute kidney injury on Covid-19 outcomes in patients with and without chronic kidney disease: a multicenter retrospective cohort study(Tubitak Scientific & Technological Research Council Turkey, 2021) Ozturk, Savas; Turgutalp, Kenan; Arici, Mustafa; Cetinkaya, Hakki; Altiparmak, Mehmet Riza; Aydin, Zeki; Soypacaci, ZekiBackground/aim: Hospital-acquired acute kidney injury (HA-AKI) may commonly develop in Covid-19 patients and is expected to have higher mortality. There is little comparative data investigating the effect of HA-AKI on mortality of chronic kidney disease (CKD) patients and a control group of general population suffering from Covid-19. Materials and methods: HA-AKI development was assessed in a group of stage 3-5 CKD patients and control group without CKD among adult patients hospitalized for Covid-19. The role of AKI development on the outcome (in-hospital mortality and admission to the intensive care unit [ICU]) of patients with and without CKD was compared. Results: Among 621 hospitalized patients (age 60 [IQR: 47-73]), women: 44.1%), AKI developed in 32.5% of the patients, as stage 1 in 84.2%, stage 2 in 8.4%, and stage 3 in 7.4%. AKI developed in 48.0 % of CKD patients, whereas it developed in 17.6% of patients without CKD. CKD patients with HA-AKI had the highest mortality rate of 41.1% compared to 14.3% of patients with HA-AKI but no CKD (p < 0.001). However, patients with AKI+non-CKD had similar rates of ICU admission, mechanical ventilation, and death rate to patients with CKD without AKI. Adjusted mortality risks of the AKI+non-CKD group (HR: 9.0, 95% CI: 1.9-44.2) and AKI+CKD group (HR: 7.9, 95% CI: 1.9-33.3) were significantly higher than that of the non-AKI+non-CKD group. Conclusion: AKI frequently develops in hospitalized patients due to Covid-19 and is associated with high mortality. HA-AKI has worse outcomes whether it develops in patients with or without CKD, but the worst outcome was seen in AKI+CKD patients.Öğe THE LONGITUDINAL EVOLUTION OF COVID-19 OUTCOMES AMONG HEMODIALYSIS PATIENTS: A NATIONWIDE MULTICENTRE CONTROLLED STUDY(Oxford Univ Press, 2022) Ozturk, Savas; Turgutalp, Kenan; Arici, Mustafa; Gorgulu, Numan; Tonbul, Halil Zeki; Eren, Necmi; Gencer, Vedat[Abstract Not Availabe]Öğe The Longitudinal Evolution of Post-COVID-19 Outcomes Among Hemodialysis Patients in Turkey(Elsevier Science Inc, 2022) Ozturk, Savas; Turgutalp, Kenan; Arici, Mustafa; Gorgulu, Numan; Tonbul, Halil Zeki; Eren, Necmi; Gencer, VedatIntroduction: Hemodialysis (HD) patients have increased risk for short-term adverse outcomes of COVID-19. However, complications and survival at the post-COVID-19 period have not been published extensively.Methods: We conducted a national, multicenter observational study that included adult maintenance HD patients recovered from confirmed COVID-19. A control HD group without COVID-19 was selected from patients in the same center. We investigated the characteristics and outcomes in the follow-up of HD patients and compare them with the non-COVID-19 group.Results: A total of 1223 patients (635 patients in COVID-19 group, 588 patients in non-COVID-19 group) from 47 centers were included in the study. The patients' baseline and HD characteristics were almost similar. The 28th-day mortality and mortality between 28th day and 90th day were higher in the COVID-19 group than non-COVID-19 group (19 [3.0%] patients vs. none [0%]; 15 [2.4%] patients vs. 4 [0.7%] patients, respectively). The presence of respiratory symptoms, rehospitalization, need for home oxygen therapy, lower respiratory tract infection, and arteriovenous (AV) fistula thrombosis was significantly higher in the COVID-19 group in both the first 28 days and between 28 and 90 days. In the multivariable analysis, age (odds ratio [OR] [95% CI]: 1.029 [1.004-1.056]), group (COVID-19 group vs. non-COVID-19 group) (OR [95% CI]: 7.258 [2.538-20.751]), and vascular access type (tunneled catheter/AV fistula) (OR [95% CI]: 2.512 [1.249-5.051]) were found as independent parameters related to 90-day mortality.Conclusion: In the post-COVID-19 period, maintenance HD patients who have had COVID-19 have increased rehospitalization, respiratory problems, vascular access problems, and high mortality compared with the non-COVID-19 HD patients.Öğe MEMBRANOUS NEPHROPATHY IN TURKEY: TURKISH SOCIETY OF NEPHROLOGY GLOMERULER DISEASES (TSN-GOLD) DATABASE RESULTS(Oxford Univ Press, 2020) Yildiz, Abdulmecit; Ulu, Memnune Sena; Oruc, Aysegul; Ucar, Ali Riza; Ozturk, Savas; Alagoz, Selma; Eren, Necmi[Abstract Not Availabe]Öğe Middle-term outcomes in renal transplant recipients with COVID-19: a national, multicenter, controlled study(Oxford Univ Press, 2022) Oto, Ozgur Akin; Ozturk, Savas; Arici, Mustafa; Velioglu, Arzu; Dursun, Belda; Guller, Nurana; Sahin, IdrisBackground In this study, we evaluated 3-month clinical outcomes of kidney transplant recipients (KTR) recovering from COVID-19 and compared them with a control group. Method The primary endpoint was death in the third month. Secondary endpoints were ongoing respiratory symptoms, need for home oxygen therapy, rehospitalization for any reason, lower respiratory tract infection, urinary tract infection, biopsy-proven acute rejection, venous/arterial thromboembolic event, cytomegalovirus (CMV) infection/disease and BK viruria/viremia at 3 months. Results A total of 944 KTR from 29 different centers were included in this study (523 patients in the COVID-19 group; 421 patients in the control group). The mean age was 46 +/- 12 years (interquartile range 37-55) and 532 (56.4%) of them were male. Total number of deaths was 8 [7 (1.3%) in COVID-19 group, 1 (0.2%) in control group; P = 0.082]. The proportion of patients with ongoing respiratory symptoms [43 (8.2%) versus 4 (1.0%); P Conclusion The prevalence of ongoing respiratory symptoms increased in the first 3 months post-COVID in KTRs who have recovered from COVID-19, but mortality was not significantly different.Öğe Mortality analysis of COVID-19 infection in chronic kidney disease, haemodialysis and renal transplant patients compared with patients without kidney disease: a nationwide analysis from Turkey(Oxford Univ Press, 2020) Ozturk, Savas; Turgutalp, Kenan; Arici, Mustafa; Odabas, Ali Riza; Altiparmak, Mehmet Riza; Aydin, Zeki; Cebeci, EgemenBackground. Chronic kidney disease (CKD) and immunosuppression, such as in renal transplantation (RT), stand as one of the established potential risk factors for severe coronavirus disease 2019 (COVID-19). Case morbidity and mortality rates for any type of infection have always been much higher in CKD, haemodialysis (HD) and RT patients than in the general population. A large study comparing COVID-19 outcome in moderate to advanced CKD (Stages 3-5), HD and RT patients with a control group of patients is still lacking. Methods. We conducted a multicentre, retrospective, observational study, involving hospitalized adult patients with COVID-19 from 47 centres in Turkey. Patients with CKD Stages 3-5, chronic HD and RT were compared with patients who had COVID-19 but no kidney disease. Demographics, comorbidities, medications, laboratory tests, COVID-19 treatments and outcome [in-hospital mortality and combined in-hospital outcome mortality or admission to the intensive care unit (ICU)] were compared. Results. A total of 1210 patients were included [median age, 61 (quartile 1-quartile 3 48-71) years, female 551 (45.5%)] composed of four groups: control (n = 450), HD (n = 390), RT (n = 81) and CKD (n = 289). The ICU admission rate was 266/1210 (22.0%). A total of 172/1210 (14.2%) patients died. The ICU admission and in-hospital mortality rates in the CKD group [114/289 (39.4%); 95% confidence interval (CI) 33.9-45.2; and 82/289 (28.4%); 95% CI 23.9-34.5)] were significantly higher than the other groups: HD = 99/390 (25.4%; 95% CI 21.3-29.9; P < 0.001) and 63/390 (16.2%; 95% CI 13.0-20.4; P < 0.001); RT = 17/81 (21.0%; 95% CI 13.2-30.8; P = 0.002) and 9/81 (11.1%; 95% CI 5.7-19.5; P = 0.001); and control = 36/450 (8.0%; 95% CI 5.8-10.8; P < 0.001) and 18/450 (4%; 95% CI 2.5-6.2; P < 0.001). Adjusted mortality and adjusted combined outcomes in CKD group and HD groups were significantly higher than the control group [hazard ratio (HR) (95% CI) CKD: 2.88 (1.52-5.44); P = 0.001; 2.44 (1.35-4.40); P = 0.003; HD: 2.32 (1.21-4.46); P = 0.011; 2.25 (1.23-4.12); P = 0.008), respectively], but these were not significantly different in the RT from in the control group [HR (95% CI) 1.89 (0.76-4.72); P = 0.169; 1.87 (0.81-4.28); P = 0.138, respectively]. Conclusions. Hospitalized COVID-19 patients with CKDs, including Stages 3-5 CKD, HD and RT, have significantly higher mortality than patients without kidney disease. Stages 3-5 CKD patients have an in-hospital mortality rate as much as HD patients, which may be in part because of similar age and comorbidity burden. We were unable to assess if RT patients were or were not at increased risk for in-hospital mortality because of the relatively small sample size of the RT patients in this study.Öğe Predicting the outcome of COVID-19 infection in kidney transplant recipients(Bmc, 2021) Oto, Ozgur Akin; Ozturk, Savas; Turgutalp, Kenan; Arici, Mustafa; Alpay, Nadir; Merhametsiz, Ozgur; Sipahi, SavasBackgroundWe aimed to present the demographic characteristics, clinical presentation, and outcomes of our multicenter cohort of adult KTx recipients with COVID-19.MethodsWe conducted a multicenter, retrospective study using data of patients hospitalized for COVID-19 collected from 34 centers in Turkey. Demographic characteristics, clinical findings, laboratory parameters (hemogram, CRP, AST, ALT, LDH, and ferritin) at admission and follow-up, and treatment strategies were reviewed. Predictors of poor clinical outcomes were analyzed. The primary outcomes were in-hospital mortality and the need for ICU admission. The secondary outcome was composite in-hospital mortality and/or ICU admission.ResultsOne hundred nine patients (male/female: 63/46, mean age: 48.412.4years) were included in the study. Acute kidney injury (AKI) developed in 46 (42.2%) patients, and 4 (3.7%) of the patients required renal replacement therapy (RRT). A total of 22 (20.2%) patients were admitted in the ICU, and 19 (17.4%) patients required invasive mechanical ventilation. 14 (12.8%) of the patients died. Patients who were admitted in the ICU were significantly older (age over 60years) (38.1% vs 14.9%, p=0.016). 23 (21.1%) patients reached to composite outcome and these patients were significantly older (age over 60years) (39.1% vs. 13.9%; p=0.004), and had lower serum albumin (3.4g/dl [2.9-3.8] vs. 3.8g/dl [3.5-4.1], p=0.002), higher serum ferritin (679 mu g/L [184-2260] vs. 331 mu g/L [128-839], p=0.048), and lower lymphocyte counts (700/mu l [460-950] vs. 860 /mu l [545-1385], p=0.018). Multivariable analysis identified presence of ischemic heart disease and initial serum creatinine levels as independent risk factors for mortality, whereas age over 60years and initial serum creatinine levels were independently associated with ICU admission. On analysis for predicting secondary outcome, age above 60 and initial lymphocyte count were found to be independent variables in multivariable analysis.Conclusion Over the age of 60, ischemic heart disease, lymphopenia, poor graft function were independent risk factors for severe COVID-19 in this patient group. Whereas presence of ischemic heart disease and poor graft function were independently associated with mortality.Öğe Prediction of nano etching parameters of silicon wafer for a better energy absorption with the aid of an artificial neural network(Elsevier Science Bv, 2018) Kayabasi, Han; Ozturk, Savas; Celik, Erdal; Kurt, Huseyin; Arcaldioglu, ErolTo enhance energy absorption of photovoltaics, several etching experiments with various parameters were performed. In addition, an Artificial Neural Network (ANN) simulation was utilized to predict chemical nano etching parameters such as masking and etching durations for Silicon (Si) solar cell applications to reach minimum surface reflectance in an optimum etching duration. Experiments were performed with different masking and etching durations to determine the characteristics of surface reflectance of micro textured n-type single crystalline Si wafers in 25mmx25mm width and 300 gm thickness to provide training data for ANN. For this purpose, solutions with identic properties including Ag nanoparticles were applied with different application durations on the surfaces of n-type single crystalline Si wafers to cover partially the Si surfaces with Ag nano-particles at masking step. After, partially masked Si surfaces were exposed to chemical nano etching to develop nano-sized porous structures under different etching durations in an identic acidic etching solution. For the etching of Si wafers, 32 masking and etching processes were performed. Reflectance measurements and SEM images were evaluated to determine the optimum etching duration resulting the best surface quality with minimum reflectance. In addition, reflectance values were utilized as input data for training, testing and validation steps of developed ANN. In the ANN simulation, 70% of reflectance values were used as training, 15% of reflectance values were used as validation and 15% of reflectance values were used to test data in the ANN. Consequently, surface reflectance values under different masking and etching durations were predicted with the new parameter set by using the trained ANN with a success level above 99%.Öğe THE RELATIONSHIP BETWEEN SEVERITY OF INTERSTITIAL FIBROSIS AND ANEMIA IN PATIENT WITH PRIMARY GLOMERULONEPHRITIS: THE DATA FROM TSN-GOLD WORKING GROUP(Oxford Univ Press, 2020) Cebeci, Egemen; Turgutalp, Kenan; Ozturk, Savas; Ozluk, Yasemin; Bek, Sibel Gokcay; Sumnu, Abdullah; Seyahi, Nurhan[Abstract Not Availabe]Öğe TRENDS OF PRIMARY GLOMERULAR DISEASE IN TURKEY FROM 2009 TO 2017: A REGIONAL REGISTRY REPORT FROM TSN-GOLD WORKING GROUP(Oxford Univ Press, 2020) Gul, Cuma Bulent; Kucuk, Mehmet; Ozturk, Savas; Demir, Erol; Eren, Necmi; Sumnu, Abdullah; Seyahi, Nurhan[Abstract Not Availabe]Öğe Trends of primary glomerular disease in Turkey: TSN-GOLD registry report(Springer, 2022) Gul, Cuma Bulent; Kucuk, Mehmet; Ozturk, Savas; Demir, Erol; Eren, Necmi; Sumnu, Abdullah; Seyahi, NurhanBackground Although several renal biopsy registry reports have been published worldwide, there are no data on primary glomerular disease trends in Turkey. Methods Three thousand eight-hundred fifty-eight native kidney biopsy records were assessed in the Turkish Society of Nephrology Primary Glomerulopathy Working Group (TSN-GOLD) Registry. Secondary disease and transplant biopsies were not recorded in the registry. These records were divided into four periods, before 2009, 2009 to 2013, 2013-2017, and 2017-current. Results A total of 3858 patients (43.6% female, 6.8% elderly) were examined. Nephrotic syndrome was the most common biopsy indication in all periods (58.6%, 53%, 44.1%, 51.6%, respectively). In the whole cohort, IgA nephropathy (IgAN) (25.7%) was the most common PGN with male predominance (62.7%), and IgAN frequency steadily increased through the periods (x 2 = 198, p < 0.001). MGN was the most common nephropathy in the elderly (> 65 years), and there was no trend in this age group. An increasing trend was seen in the frequency of overweight patients (x 2 = 37, p < 0.0001). Although the biopsy rate performed with interventional radiology gradually increased, the mean glomeruli count in the samples did not change over the periods. Conclusions In Turkey, IgAN is the most common primary glomerulonephritis, and the frequency of this is increasing.
