Scopus Kapalı Erişimli Yayınlar

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Adrenergic receptor behaviors of mesenchymal stem cells obtained from different tissue sources and the effect of the receptor blockade on differentiation
(2021) Maytalman, Erkan; Alizadeh Yegani, Arash; Kozanoglu, Ilknur; Aksu, Fazilet; 0000-0002-5268-1210; 34323168; AAE-1241-2021
In this study, it was aimed to analyze behavioral changes of adrenergic receptors (ARs) in first three passages and osteogenic/adipogenic differentiation of mesenchymal stem cells (MSCs) derived from placenta fetal membrane (FM) and bone marrow (BM). It was also aimed to evaluate effects of receptor blockade on differentiation. We obtained first three passages of MSCs from placenta and BM samples. For cell identification, the cells were analyzed by flow cytometry using CD34, CD45 and CD3, CD105 antibodies in each passage. The effects of propranolol and phenoxybenzamine at incremental doses were analyzed by MTT. In addition, cell cultures were separately maintained with the blockers or without after second passage. After each passage and differentiation, alpha 1A, alpha 1B, alpha 2A, alpha 2B, beta 1, beta 2, beta 3 AR-mRNA expressions analyzed by RT-qPCR technique. BMP6 and PPARG mRNA expressions only after differentiation and passage 3 were analyzed. A microscopic examination was also performed. Our results showed that AR expression behaviors were different in MSCs obtained from different tissue sources. In particular, alpha(1A)-AR and alpha(2A)-AR were expressed with considerably high coefficients in differentiation under blocker effect in BM-derived MSCs. No such coefficients were observed in any group of placental MSCs. In addition, it was found that the blockers stimulated adipogenesis in BM-derived MSCs during osteogenic differentiation. MSCs exhibit protein expressions that vary according to source of tissue and differentiation. Given that MSCs from different sources are used for repair and modulation, our study makes implications of this variable expression intriguing in the clinical practice.
Airfoil-slat arrangement model design for wind turbines in fuzzy environment
(2020) Atalay, Kumru Didem; Dengiz, Berna; Yavuz, Tahir; Koc, Emre; Ic, Yusuf Tansel
In this study, a multi-element wind turbine blade that consists of NACA 6411 and NACA 4412 leading-edge slat design is investigated computationally. Optimum design parameters of the slatted wind turbine blade leading to maximum value of C-L/C-D related to the turbine power are obtained. In the optimization process, a new fuzzy logic linear programming methodology integrating with fuzzy linear regression and 2D CFD analysis is proposed. The aerodynamic characteristics of the slatted blade are computed by using Incompressible Navier-Stokes equations and k-omega turbulence modeling. Results are compared with the results of linear programming method and direct search optimization method. The computational results reveal that the proposed methodology for performance optimization is more effective than other methods to obtain high-performance value of the C-L/C-D. The maximum value of the C-L/C-D is obtained as 25.1 leading the maximum efficiency of 0.52.
An Alternative Low-Cost Solution for Tracking Laboratory Animals
(2020) Kiziltan, Erhan; Aydin, Leyla; 0000-0001-6029-3835; AAD-6090-2021
Objectives: Monitoring animal behavior under various conditions can provide important information on their neuropsychological status, including learning, memory, and cognitive activity. Several commercial tracking systems are available, but they may be too expensive for low-budget projects. This study developed an alternative solution for automated animal tracking in behavioral experiments. Methods: The proposed system was designed to analyze a set of images sampled from a recorded video file in chronological order. The instantaneous location of the animal in each image frame was defined automatically, using a feature-extraction algorithm. Distances traveled were calculated using the coordinates of the successive instantaneous locations. The algorithm was tested using two arenas: the Morris water maze and open field test. The calculated measures were compared with those obtained manually. The internal consistency of the dataset was checked using Cronbach's alpha. The accuracy of the results was evaluated using the paired samples t-test and Pearson correlation, with the level of statistical significance set at p<0.01. Results: A statistical comparison of the distances traveled, which were derived from the coordinates of successive locations, did not differ significantly between the manual and automatic methods (r=0.954 and p=0.792 for the Morris water maze; r=0.996 and p=0.024 for the open field test). Conclusions: These results suggest that the algorithm is reliable and valid for estimating coordinates and may serve as a high-resolution tool for animal behavior experiments. We intend to make this software freely available to interested readers and to open feedback channels for further development.
Analysis of Probiotic Bacteria Genomes: Comparison of CRISPR/Cas Systems and Spacer Acquisition Diversity
(2021) Ilikkan, Ozge Kahraman; 0000-0001-5843-6868; 35068602; Q-9641-2019
Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) genes constitute an adaptive (acquired) defense system of bacteria and archaea. Here 72 probiotic bacteria genomes were investigated in terms of the presence of CRISPR/Cas systems and phage/plasmid invaders through spacer analysis. 49 CRISPR/Cas systems were detected within probiotic strains, namely,17 type II-A, 10 type I-C, 8 type I-E, 5 Type I-U (I-G), 4 type III-A, 2 type I-B, 1 type I-A, 1 type IV-B, and 1 type II-C. The predicted target of spacers was determined in 25 strains and consequently, three different spacer and target patterns were revealed. The diversity of CRISPR spacers provides insight and understanding to determine strain-specific invaders of probiotic bacteria as well as their relationships between strains. CRISPR systems were clarified in many studies for genomic characterization. However, recently, endogenous genome editing with CRISPR has provided an approach for various genome editing projects. Thus, in the future, producing strain-specific phage-resistant starter cultures or probiotics by endogenous genome editing methods according to phage/plasmid survey can be utilized for industrial and pharmaceutical applications. Therefore, this study intended a comprehensive investigation of CRISPR systems of probiotic bacteria.
Analysis of the IR-Raman Modes and the Heat Capacity Near the alpha-Inc-beta Transitions in Quartz
(2021) Yurtseven, H.; Gunay, E.; Karacali, H.; Ates, S.
This study gives our analysis for the temperature dependence of the infrared frequency and the integrated intensity of the 695 cm(-1) mode near the alpha-beta transition at 847.5 K and the temperature dependence of the Raman scattering cross section of the 355 cm(-1) mode near the beta-INC (incommensurate) transition which occurs within a small temperature (similar to 1.3 K) interval in relation to the order parameter in quartz. Both analyses are performed according to a power-law formula for the order parameter Q with the critical index beta using the experimental data from the literature. We also analyze the temperature dependence of the heat capacity C p according to the renormalization-group expression including first-order corrections to scaling term close to the alpha-INC-beta transitions in quartz by using the literature data. From our analyses, values of the critical exponent beta for the frequency and the integrated intensity of the 695 cm(-1) infrared mode and for the Raman scattering cross section of the 355 cm(-1) mode as a measure of the order parameter, are extracted. From the analysis of C p , the values of the critical exponent alpha are also extracted. Additionally, by means of scaling relations the critical exponent gamma of the isothermal compressibility kappa T and the renormalized components ( beta R , alpha R and gamma R ) are predicted for the alpha-INC-beta transitions in quartz. Our analyses given here indicate that weakly first-order transition occurs from the alpha phase to the incommensurate (INC) phase, which changes to the nearly second-order transition to the beta phase with increasing temperature in quartz, as also observed experimentally.
Analysis of the manufacturing flexibility parameters with effective performance metrics: a new interactive approach based on modified TOPSIS-Taguchi method
(2022) Ic, Yusuf Tansel; Sasmaz, Turgut; Yurdakul, Mustafa; Dengiz, Berna; 0000-0001-9274-7467; AGE-3003-2022
Flexibility is one of the most important strategy parameters to achieve a long-term successful performance for a manufacturing company. Studies in the literature aim to operate a manufacturing system at optimum levels of flexibility parameters under its own manufacturing environment. This study aims to present an interactive analysis framework based on TOPSIS and Taguchi parameter design principles for investigating the effects of different levels of flexibility parameters on the performance of a flexible manufacturing cell (FMC). The main performance metric used in this study is manufacturing lead time. Other important metrics to evaluate quality control and inspection policies are also investigated in this study. To conclude, a combined model of an interactive approach based on TOPSIS and Taguchi methods are used to assess the effectiveness of the flexibility parameters for a FMC.
Analysis of The Performance of A Solar Air Heater With Different Configurations: Effect of Fins And Turbulators
(2022) Erol, Ozgur
Solar air heaters are simple tools used to harvest the energy of the sun. The main objective of the solar air heater design is to get the highest thermal energy from the sun. In order to do this different kinds of fins and turbulators are placed in the flow channel of the solar air heater, which also affects the flow characteristic of the working fluid. In this study, the performance of two different configurations, a turbulator placed at the bottom of the channel and a longitudinal rectangular fin placed on the absorber plate, are investigated using different performance parameters. These parameters are the thermal efficiency, rational exergy management method (REMM) efficiency, flow work, and the temperature distribution on the absorber plate. According to the results, both of the test cases have nearly the same performance, which is higher than the flat solar air except the flow work. When the heat gain per unit flow work is investigated, it can be said that turbulator configuration is the best choice among the configurations that are investigated.
Analysis of the relationship between tuberculosis-related mortality and nitrous oxide emission levels in the world with the environmental Kuznets curve method
(2022) Torun, Serife; Yilmaz, Kadir; Ozkaya, Sevket; Yosunkaya, Sebnem; Akcay, Sule; 36326361
Background/aim: It was aimed to analyze the relationship between tuberculosis-related mortality and nitrous oxide emission levels in the world with the Environmental Kuznets Curve (EKC) Method. Materials and methods: WHO ICD-10 mortality list data and the World Bank Country Data (WBCD) were used between 1997 and 2017 for 12 countries. Cubic regression analysis was used for EKC Analysis. Results: The difference between male and female deaths between 1996 and 1998 has increased sharply since 1999. Male deaths consistently occurred significantly more than female deaths. There was a significant and negative correlation between Nitrous oxide emissions (% change from 1990) and tuberculosis-related deaths, whereas there were significant and positive correlations between Nitrous oxide emissions in the energy sector (% of total) and tuberculosis-related deaths (p < 0.01). EKC analysis results showed that there is a U shaped between tuberculosis-related mortality and nitrous oxide emission levels in the world. Conclusion: Research results show that the relationship between nitrous oxide change and mortality is negative in the short term and positive in the long term. Therefore, although nitrous oxide gases cause respiratory diseases and mortality, it may be possible to transform a harmful environmental factor into a positive by developing devices or methods that will convert these gases into free radicals.
Analysis of the Robustness of the Operational Performance Using a Combined Model of the Design of Experiment and Goal Programming Approaches for a Flexible Manufacturing Cell
(2023) Ic, Yusuf Tansel; Yurdakul, Mustafa; Dengiz, Berna; Sasmaz, Turgut
A combined model of a 2(k) design of experiment (DOE) and goal programming (GP) approaches is presented to determine optimum levels of input variables and analyze their robustness for a multiobjective performance of a flexible manufacturing cell (FMC) in this study. Two main performance metrics, namely, manufacturing lead time (MLT) and surface roughness (SR), are considered performance outputs for the FMC. Machine sequence, robot speed, tool type, and material type are selected as the four input variables on the input side of the proposed model. The study shows that even with a limited number of experiments, one can determine optimum input levels for the multiobjective performance of the FMC and determine their robustness.
An analysis of Turkey's solar PV auction scheme: What can Turkey learn from Brazil and South Africa?
(2021) Sirin, Selahattin Murat; Sevindik, Irem
As global investments continue in renewable energy technologies, investment costs have declined significantly. Meanwhile, many governments have shifted from pre-set renewable support schemes to auction schemes in order to introduce competition in price setting. Turkey has initiated Renewable Energy Resource Zone (RERZ) auctions to promote solar photovoltaic (PV) and wind technologies. We examine the first of these auctions, Solar PV RERZ, which has ambitious targets in terms of increasing solar PV capacity and enhancing domestic competence in solar technologies. Despite the auction being hailed as a success in terms of low prices, we utilize the Levelized Cost of Electricity generation (LCOE) analysis to demonstrate that the project is vulnerable to macroeconomic shocks and financial risks. Model results show that the capacity factor is the most prominent factor in costs, and 10% change in the capacity factor affects the LCOE about the same rate. Investment cost and interest rate are the other major factors affecting the LCOE. Based on these results, we make recommendations by discussing how Turkey can improve its auction design by incorporating some of the elements used by Brazil and South Africa.
Anocutaneous Reflex Revisited: How Valuable Is Its Determination in Children with Spina Bifida? A Descriptive Study in A Cohort of 217 Patients
(2022) Ozel, Kerem; Canmemis, Arzu; Goknar, Nilufer; Candan, Cengiz; Alizada, Orkhan; Alatas, Ibrahim; 35147971
AIM: To determine the clinical value of anocutaneous reflex (AR) in children with neurogenic bladder due to spina bifida (SB). MATERIAL and METHODS: Patients who were diagnosed with SB were prospectively evaluated; moreover, AR and bulbocavernous reflex were examined. Patients were divided into those with and without AR. Age, gender, diagnosis, ventriculoperitoneal shunt presence, symptomatic urinary tract infections, leg movements, clean intermittent catheterization and anticholinergic therapy, lesion level, urodynamic detrusor, and sphincter activity were evaluated. Chi-square test and univariate regression analysis were done. The AR value was evaluated by two by two contingency table. RESULTS: This study evaluated 217 patients (109 boys and 108 girls). AR was present and absent in 53 and 164 patients, respectively. Anticholinergic therapy was necessary in 37.7% and 23.8% of patients with and without AR (p=0.015), respectively. Patients with AR had higher lesion level (p=0.005), more detrusor overactivity, and less detrusor underactivity (p=0.007). Less detrusor sphincter dyssynergia (DSD) was noted in patients with AR (p=0.029). AR specificity was 83%, and positive predictive value in predicting detrusor overactivity and DSD was 76% and 80, respectively. CONCLUSION: AR determination is a valuable and simple tool in neurogenic bladder. This report delineates the clinical significance of this reflex and is the largest cohort describing this significance. This simple examination should not be skipped in the initial evaluation and follow-up of these patients
Antecedents of Nurse Burnout During a Pandemic: Managerial Way Out
(2022) Basar, Ufuk; Dogan, Aysun; Ertugrul, Bekir
The aim of this research is to uncover whether nurses' fear of contracting Coronavirus Disease 2019 (COVID-19) has resulted in stress-related presenteeism and burnout, and whether perceived organisational support is effective in dealing with both nurses' fear of contracting COVID-19 and its undesired consequences. For this purpose, a cross-sectional and descriptive research has been conducted. The data are collected from 513 nurses working in Ankara, Turkey, through a questionnaire survey. Independent samples t-test, one-way analysis of variance test and partial least squares structural equation modelling technique are employed to analyse the data. Findings indicate that nurses fear infection and experience stress-related presenteeism and burnout considerably. However, they perceive slightly inadequate level of organisational support. Fear of infection has resulted in stress-related presenteeism and burnout. Stress-related presenteeism has mediated the relationship between fear of infection and burnout. Perceived organisational support has negatively related to fear of infection and its negative consequences. In this research, to our knowledge, for the first time, the burnout, stress-related presenteeism, fear of infection and perceived organisational support levels of nurses are compared according to the pandemic-related criteria. Besides, the mediating role of nurses' stress-related presenteeism between their fear of contracting COVID-19 and burnout is discovered.
Antecedents of tourist food consumption: food choice motives of foreign tourists in Turkey
(2023) Ekizler, Huseyin; Oksuz, Merve; Durmus, Beril; Shipman, Zehra Dilistan; 0000-0003-2470-7919
Culinary or gastronomy tourism has become a rising issue nowadays. People want to discover new flavour while travelling. Food consumption is the combination of one's cultural, social, psychological and sensory acceptance factors and it is a very complex decision-making process. Food consumption is also associated with motivational factors which are mood, health, sensory appeal, familiarity, convenience, price and natural content. The antecedents of tourist food consumption and food choice motives of foreign tourists in Istanbul were examined. The results show that sensory appeal, mood, natural content, health content and convenience had positive and direct connection with tourist food consumption intentions. There is no statistically significant evidence to support the associations of familiarity and price with the tourist food consumption intentions.
Antibody Immobilization Techniques in Mass Sensitive Immunosensor: Enhanced Sensitivity through Limited Mass Load
(2022) Kirali, Kubra; Brimo, Nura; Serdaroglu, Dilek Cokeliler; https://orcid.org/0000-0002-3053-2169; https://orcid.org/0000-0002-9604-263X; https://orcid.org/0000-0001-8645-9047
Background: Biosensors are analytical devices that include a sample-delivery approach between a biological recognition element and a transducer required to convert the physicochemical change produced from the interaction of biological molecule-receptor interaction into a signal. The immunosensor is a special type of biosensor that includes an antibody as a biorecognition element to detect analytes as antigens. In mass sensitive sensors, antigen-antibody interactions can be specified by measuring the frequency change and the most commonly knowns are the surface acoustic wave, bulk acoustic wave, quartz crystal microbalance and microcantilevers. Methods: Different methods for antibody immobilization, including functionalization of the transducer surface with specific groups, have been reported for antibody immobilization. This stage affects the limit of detection and overall performance. In this review, perspectives on immobilization strategies of mass sensitive immunosensors according to transducer types will be presented. The choice of immobilization methods and their impact on performance in terms of capture molecule loading, orientation and signal improvement will also be discussed. Results: One of the most critical points during the configuration of the biorecognition layer is to improve the sensitivity. Therefore, we initially focused on comparisons of the antibody immobilization strategies in the biorecognition layer in terms of mass load level and high sensitivity. Conclusion: The lack of significant data on the mass accumulations up to the functionalization and antibody immobilization steps, which are the basis of immusensor production, has been identified. However, mass sensitive immunosensors have the potential to become more common and effective analytical devices for many application areas.
Antiproliferative and Mitochondrial Protective Effects of Apigenin in an Oxygen-Induced Retinopathy In Vivo Mouse Model
(2021) Sezenoz, Almila Sarigul; Akkoyun, Imren; Helvacioglu, Fatma; Haberal, Nihan; Dagdeviren, Attila; Bacanli, Didem; Yilmaz, Gursel; Oto, Sibel; 0000-0002-2860-7424; 34665015; AAK-7713-2021
Purpose: To investigate the effects of a common dietary flavonoid apigenin on retinal endothelial cell proliferation, retinal morphological structure, and apoptotic cell death in an oxygen-induced retinopathy (OIR) mouse model to evaluate the possibility of the use of apigenin in the treatment of ocular neovascular diseases (ONDs). Methods: Ninety-six newborn C57BL/6J mice were included. Eight groups were randomized, each including 12 mice. Two negative control groups were kept in room air: the first without any injection and the second received intravitreal (IV) dimethyl sulfoxide (DMSO), which is the solvent we used. The OIR groups were exposed to 75% +/- 2% oxygen from postnatal days (PD) 7 to 12. On PD 12, the mice were randomly assigned to 6 groups: 2 OIR control groups (1 received no injection, 1 received IV-DMSO), 2 IV-apigenin groups (10 and 20 mu g/mL), and 2 intraperitoneal (IP)-apigenin groups (10 and 20 mg/kg). We quantified retinal endothelial cell proliferation by counting neovascular tufts in cross-sections and examined histological and ultrastructural changes through light and electron microscopy. We evaluated apoptosis by terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL). Results: We detected a significant increase in endothelial cell proliferation in the OIR groups. Groups receiving apigenin, both IP and IV, had significant decreases in endothelial cells, atypical mitochondrion count, and apoptotic cells compared with the groups receiving no injections. None of the apigenin-injected groups revealed cystic degeneration or cell loss. Conclusions: Apigenin suppresses neovascularization, has antiapoptotic and antioxidative effects in an OIR mouse model, and can be considered a promising agent for treating OND. Clinical trial (Project number: DA15/19).
Anxiety Levels and Changes in Health and Hygiene Behaviors in Mothers of Children with Asthma in Early COVID-19 Lockdown in Turkey
(2022) Sancakli, Ozlem; Tuncel, Tuba; Eren Akarcan, Sanem; Kanik, Ali; Ozyurt, Gonca; Ozdogru, Emine Ece; 35290751
Objective: The restrictions imposed by the coronavirus disease 2019 (COVID-19) pandemic have caused significant changes in people's lives. This study aimed to investigate anxiety levels and changes in health and hygiene behaviors in mothers of children with asthma in early COVID-19 lockdown in Turkey.Materials and Methods: This study was a cross-sectional survey conducted on children with asthma, 6 to 11 years of age, between June 1 and 30, 2020, in Turkey. A sociodemographic data form, health and hygiene behavior form, childhood asthma control test, and state-trait anxiety inventory were administered to the mothers of the children.Results: The asthma group included 123 children (Female: 39.0%) and median age, interquartile range (IQR) [minimum-maximum]: 8.0 (6) [6-12] years; the control group included 88 children (Female: 47.7%) median age, IQR [minimum-maximum]: 8.0 (7) [5-12] years. Increased hygiene behaviors and high compliance with social isolation measures were recorded in the early lockdown, with no difference between the groups. Before the pandemic, the most frequently used cleaning products were general-purpose cleaners. During the early lockdown, however, the most frequently used product was disinfectants and was similar in both groups.In both groups, the rate of using nutritional supplements increased during the pandemic period, but the rate was higher in children with asthma both before and during the early lockdown (P < 0.001). The anxiety levels of the mothers in asthma and control groups were similar.Conclusion: This study is the first in Turkey demonstrating that, in mothers of children with asthma, lifestyle changes related to health and hygiene and anxiety levels are similar to those of other children and their mothers during the early lockdown period of COVID-19 pandemic.
Aortic arch calcification: a novel parameter for prediction of masked hypertension
(2021) Akbay, Ertan; Coner, Ali; Akinci, Sinan; Adar, Adem; Cakan, Fahri; Muderrisoglu, Haldun; 0000-0002-9146-0621; 0000-0002-5711-8873; 0000-0001-5250-5404; 0000-0002-5427-3480; 33734125; AAD-5479-2021; ABD-7321-2021; AAD-5564-2021; GPT-4057-2022
Background Masked hypertension is directly related to increased cardiovascular morbidity and mortality but remains underdiagnosed in clinical practice. The aim of the study was to search the role of aortic arch calcification (AAC) in the diagnosis of masked hypertension. Methods and results Among the patients who underwent ambulatory blood pressure monitoring (ABPM) in our clinic, those with office blood pressure (OBP) <140/90 mmHg were included in the study population. According to OBP, they were divided into two groups as normal (<130/85 mmHg) and high normal (130-139/85-89 mmHg) OBP groups. Subjects were also investigated for the presence of masked hypertension with ABPM and searched in masked hypertension and control groups. Masked hypertension was defined as in the latest 2017 ACC/AHA Hypertension guideline and was diagnosed as the daytime BP >= 135/85 mmHg and nighttime BP >= 120/70 mmHg. AAC was evaluated on direct X-ray telecardiography. Diagnosis of masked hypertension was searched depending on the presence of AAC and OBP measurements as well. A total of 216 volunteers were involved in the study [mean age 45.2 +/- 12.2 years; female gender 120 (55.5%)]. One hundred ten volunteers (50.9%) had masked hypertension according to the ABPM. AAC was significantly more common in the masked hypertension group (44.5% vs. 26.4%) (P = 0.005). AAC had a positive predictive value of 79% in those with high normal OBP in the diagnosis of masked hypertension, and also AAC had a negative predictive value of 74% in those with normal OBP. Conclusion AAC can be used as a reliable diagnostic tool to exclude and predict masked hypertension during office examination.
Apparently We Cannot Live, We are like Infectious Zombies: A Qualitative Research on Personal and Familial Experiences of Health Workers in the Filiation Teams in Turkey during the COVID-19 Pandemic
(2022) Karatas, Mustafa; Gure, Merve Deniz Pak; Duyan, Veli; https://orcid.org/0000-0002-0998-2552; 35658819
This study aims to examine the experiences of health workers in filiation teams in Turkey. The qualitative research model has been used. 375 health workers have participated using a non-probability sampling method. The data were collected over the internet using the questionnaire. The data have been analyzed with the MAXQDA and various code-sub codes-segment maps and code matrices have been used. The results expressed in two dimensions: instrumental and emotional areas. It has been observed that issues such as burnout, loss of motivation, and future anxiety have often been coded due to poor working conditions of the filiation teams, lack of rewards, and other factors. They have been determined as experiencing social stigma along with fear of infecting their families, and therefore have problems with child care, visiting adult family members in the risk group. It is recommended to develop psychosocial support services and improve organizational conditions.
Application of the international classification of diseases-perinatal mortality (ICD-PM) system to stillbirths: A single center experience in a middle income country
(2022) Dagdeviren, Gulsah; Uysal, Nihal Sahin; Dilbaz, Kubra; Celen, Sevki; Caglar, Ali Turhan; 34890860
Objective: The present study is intended to investigate the causes of stillbirth and its relationship with maternal conditions using the International Classification of Diseases-Perinatal Mortality (ICD-PM) system.Material and methods: All early and late fetal deaths between 2015 and 2020 were analyzed. Time of death, fetal causes, and the maternal conditions involved were identified using the ICD-PM classification system.Results: During the study period, out of 74,102 births a total of 475 stillbirths were recorded (6.4 per 1000 births), of which 83.6% of the cases were antepartum and 11.8% were intrapartum fetal deaths, and the time of death could not be determined in 4.6% of the cases. Fetal developmental disorder was the most common cause of antepartum fetal death (24.2%). Intrapartum deaths were mostly due to extremely low birth weight (44.6%). The most common maternal conditions involved were complications of placenta, cord, and membranes (19.8%).Conclusion: The applicability of the ICD-PM classification system for stillbirths is easy. It was observed that fetal deaths mostly occurred in the antepartum period and the cause of death could not be identified in over half of these antepartum fetal deaths. In over half of the stillbirths, there is at least one maternal condition involved. The most common maternal conditions involved are complications of placenta, cord, and membranes. The most common maternal medical problem is hypertensive diseases of pregnancy. (c) 2021 Elsevier Masson SAS. All rights reserved.
Approach to recurrence of atrial fibrillation after catheter ablation
(2021) Yilmaz, Mustafa; Candemir, Basar; 33691388
Atrial fibrillation (AF) is the most commonly observed sustained rhythm disorder during adult ages. Since it has been shown that the ectopic beat initiating AF is usually caused by pulmonary veins, AF ablation has become the mainstay of therapy worldwide. Cryoballoon and radiofrequency ablation are the most commonly used methods in today's technologies. However, despite technological advances, the success of a single procedure in AF ablation is still limited and multiple procedures may be required for the majority of patients. In cases in which a redo ablation is required, pulmonary vein isolation is still the main target, but non-pulmonary vein targets should also be considered in AF episodes that continue despite multiple ablations. Many issues are still unclear as to which energy to choose in the first procedure, and what ablation strategy will be utilized when a redo ablation is required. The studies on this subject are very limited but, it still seems feasible and a rational approach to utilize a customized treatment strategy in each specific patient subgroup.