Determining and Managing Fetal Radiation Dose from Diagnostic Radiology Procedures in Turkey

Mustafa Ozbayrak,Iffet Cavdar,Mehmet Seven,Lebriz Uslu,Nami Yeyin,Handan Tanyildizi,Mohammad Abuqbeitah,A. Serdar Acikgoz,Abdullah Tuten,Mustafa Demir 대한영상의학회 2015 Korean Journal of Radiology Vol.16 No.6

We intended to calculate approximate fetal doses in pregnant women who underwent diagnostic radiology procedures and to evaluate the safety of their pregnancies. We contacted hospitals in different cities in Turkey where requests for fetal dose calculation are usually sent. Fetal radiation exposure was calculated for 304 cases in 218 pregnant women with gestational ages ranging from 5 days to 19 weeks, 2 days. FetDose software (ver. 4.0) was used in fetal dose calculations for radiographic and computed tomography (CT) procedures. The body was divided into three zones according to distance from the fetus. The first zone consisted of the head area, the lower extremities below the knee, and the upper extremities; the second consisted of the cervicothoracic region and upper thighs; and the third consisted of the abdominopelvic area. Fetal doses from radiologic procedures between zones were compared using the Kruskal-Wallis test and a Bonferroni-corrected Mann-Whitney U-test. The average fetal doses from radiography and CT in the first zone were 0.05 ± 0.01 mGy and 0.81 ± 0.04 mGy, respectively; 0.21 ± 0.05 mGy and 1.77 ± 0.22 mGy, respectively, in the second zone; and 6.42 ± 0.82 mGy and 22.94 ± 1.28 mGy, respectively, in the third zone (p < 0.001). Our results showed that fetal radiation exposures in our group of pregnant women did not reach the level (50 mGy) that is known to increase risk for congenital anomalies. Fetal radiation exposure in the diagnostic radiology procedures in our study did not reach risk levels that might have indicated abortion.

Prediction of elastic modulus of steel-fiber reinforced concrete (SFRC) using fuzzy logic

Mustafa Gençoglu,Fuat Demir,Kadir Güler,Tayfun Uygunoglu 사단법인 한국계산역학회 2012 Computers and Concrete, An International Journal Vol.9 No.5

In this study, the modulus of elasticity of low, normal and high strength steel fiber reinforced concrete has been predicted by developing a fuzzy logic model. The fuzzy models were formed as simple rules using only linguistic variables. A fuzzy logic algorithm was devised for estimating the elastic modulus of SFRC from compressive strength. Fibers used in all of the mixes were made of steel, and they were in different volume fractions and aspect ratios. Fiber volume fractions of the concrete mixtures have changed between 0.25%-6%. The results of the proposed approach in this study were compared with the results of equations in standards and codes for elastic modulus of SFRC. Error estimation was also carried out for each approach. In the study, the lowest error deviation was obtained in proposed fuzzy logic approach. The fuzzy logic approach was rather useful to quickly and easily predict the elastic modulus of SFRC.

Caregiver Burden in Schizophrenia and Autism Spectrum Disorders: A Comparative Study

Mustafa Yıldız,Yasemin Demir,Ays¸ e Kırcalı,Aysel I ncedere 대한신경정신의학회 2021 PSYCHIATRY INVESTIGATION Vol.18 No.12

Objective There is no study comparing schizophrenia and autism spectrum disorders (ASD) in terms of caregiver burden. This study aims to compare the caregiver burden among family members of the patients with schizophrenia and ASD and investigate the predictive factors.Methods A cross-sectional study with the family members living with and/or providing care to their patients was carried out. A sociodemographic form, the Beck Depression Inventory, the Self-Stigma Inventory for Families, and the Zarit Caregiver Burden Scale were utilized. Regression analyses were conducted to determine the predictive factors for higher burden.Results Caregiver burden in ASD was significantly higher than in schizophrenia. Regression analysis showed that the predictors of high caregiver burden were the need for self-care (OR=3.6), self-destructive behaviors (OR=3.4), self-stigma (OR=1.1), depression (OR=1.1), and level of income (OR=1.0) for all family members. When the diagnosis was removed from the equation, the factors determining the high burden did not change.Conclusion This study suggests that characteristics of the illness are stronger predictors than family members’ characteristics in explaining high caregiver burden for both illnesses. Psychological, social, and economic supports should be provided for families to help alleviate their caregiving burden.

Does Immunohistochemistry Provide Additional Prognostic Data in Gastrointestinal Stromal Tumors?

Demir, Lutfiye,Ekinci, Nese,Erten, Cigdem,Kucukzeybek, Yuksel,Alacacioglu, Ahmet,Somali, Isil,Can, Alper,Dirican, Ahmet,Bayoglu, Vedat,Akyol, Murat,Cakalagaoglu, Fulya,Tarhan, Mustafa Oktay Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.8

Background: To investigate the predictive and prognostic effects of clinicopathologic and immunohistochemical (IHC) features in patients with gastrointestinal stromal tumours (GISTs). Materials and Methods: Fifty-six patients who were diagnosed with GIST between 2002 and 2012 were retrospectively evaluated. Relationships between clinicopathologic/immunohistochemical factors and prognosis were investigated. Results: Median overall survival (OS) of the whole study group was 74.9 months (42.8-107.1 months), while it was 95.2 months in resectable and 44.7 months in metastatic patients respectively (p=0.007). Epitheliolid tumor morphology was significantly associated with shortened OS as compared to other histologies (p=0.001). SMA(+) tumours were significantly correlated with low (<10/50HPF) mitotic activity (p=0.034). Moreover, SMA(+) patients tended to survive longer and had significantly longer disease-free survival (DFS) times than SMA (-) patients (37.7 months vs 15.9 months; p=0.002). High Ki-67 level (${\geq}30%$) was significantly associated with shorter OS (34 vs 95.2 months; 95%CI; p=0.001). CD34 (-) tumours were significantly associated with low proliferative tumours (Ki-67<%10) (p=0.026). Median PFS (progression-free survival) of the patients who received imatinib was 36 months (27.7-44.2 months). CD34 (-) patients had significantly longer PFS times than that of negative tumours; (50.8 vs 29.8 months; p=0.045). S100 and desmin expression did not play any role in predicting the prognosis of GISTs. Multivariate analysis demonstrated that ${\geq}10/50HPF$ mitotic activity/HPF was the only independent factor for risk of death in GIST patients. Conclusions: Despite the negative prognostic and predictive effect of high Ki-67 and CD34 expression, mitotic activity remains the strongest prognostic factor in GIST patients. SMA positivity seems to affect GIST prognosis positively. However, large-scale, multicenter studies are required to provide supportive data for these findings.

Hormone Receptor, HER2/NEU and EGFR Expression in Ovarian Carcinoma - is here a Prognostic Phenotype?

Demir, Lutfiye,Yigit, Seyran,Sadullahoglu, Canan,Akyol, Murat,Cokmert, Suna,Kucukzeybek, Yuksel,Alacacioglu, Ahmet,Cakalagaoglu, Fulya,Tarhan, Mustafa Oktay Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

Purpose: We aimed to evaluate the effects of hormone receptor, HER2, and epidermal growth factor receptor (EGFR) expression on epithelial ovarian cancer (EOC) prognosis and investigate whether or not phenotypic subtypes might exist. Materials and Methods: The medical records of 82 patients who were diagnosed with EOC between 2003 and 2012 and treated by platinum-based chemotherapy were retrospectively evaluated. Expression of EGFR, oestrogen (ER), progesterone (PR), and cerbB2 (HER2) receptors were assessed immunohistochemically on paraffin-embedded tissues of these patients. Three phenotypic subtypes were defined according to ER, PR, and HER2 expression and associations of these with EGFR expression, clinicopathologic features, platinum sensitivity, and survival were investigated. Results: When we classified EOC patients into three subtypes, 63.4% had hormone receptor positive (HR(+)) (considering breast cancer subtypes, luminal A), 18.3% had triple negative, and 18.3% had HER2(+) disease. EGFR positivity was observed in 37 patients (45.1%) and was significantly more frequent with advanced disease (p=0.013). However, no significant association with other clinicopathologic features and platinum sensitivity was observed. HER2(+) patients had significantly poorer outcomes than HER2(-) counterparts (triple negative and HR positive patients) (p=0.019). Multivariate analysis demonstrated that the strongest risk factor for death was residual disease after primary surgery. Conclusions: Triple negative EOC may not be an aggressive phenotype as in breast cancer. The HER2 positive EOC has more aggressive behaviour compared to triple negative and HR(+) phenotypes. EGFR expression is more frequent in advanced tumours, but is not related with poorer outcome. Additional ovarian cancer molecular subtyping using gene expression analysis may provide more reliable data.

THE SNOWFLAKE CURVE AS AN ATTRACTOR OF AN ITERATED FUNCTION SYSTEM

Demir, Bunyamin,Ozdemir, Yunus,Saltan, Mustafa Korean Mathematical Society 2013 대한수학회논문집 Vol.28 No.1

Although the snowflake curve, the boundary of the Koch snowflake, is one of the well-known fractals, there is no iterated function system (IFS) for it in the literature. In this study, we give an IFS for this familiar closed curve.

Prognostic Significance of Circulating Tumor Cells and Serum CA15-3 Levels in Metastatic Breast Cancer, Single Center Experience, Preliminary Results

Tarhan, Mustafa Oktay,Gonel, Ataman,Kucukzeybek, Yuksel,Erten, Cigdem,Cuhadar, Serap,Yigit, Seyran Ceri,Atay, Aysenur,Somali, Isil,Dirican, Ahmet,Demir, Lutfiye,Koseoglu, Mehmet Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.3

Background: Breast cancer is the second leading cancer causing death in women. Circulating tumor cells are among the prognostic factors while tumor markers are of diagnostic value and can be used for follow-up. The aim of this study was to investigate the correlation between the prognostic significance of the serum CA15-3 levels, number of circulating tumor cells and histopathological tumor factors. Materials and Methods: Thirty patients recently diagnosed with breast cancer were included in the study. Number of circulating tumor cells and serum CA15-3 level were assessed when metastasis was detected and diagnostic value was assessed. Presence of associations with estrogen and progesterone receptors, c-erbB2, Ki-67 proliferation index and histological grade were also evaluated. Results: Median overall survival of the patients with serum CA15-3 levels of >108 ng/dl was 19 months whereas for those with a low serum level it was 62 months. Median overall survival for CTC ${\geq}5$ vs CTC<5 patients was 19 months and 40 months respectively. The difference between the two groups was statistically significant. Conclusions: Prognostic significance of the CTC count and CA15-3 levels in metastatic breast cancer patients was demonstrated.

Polymers and Inorganics: A Happy Marriage?

Wegner Gerhard,Demir Mustafa M.,Faatz Michael,Gorna Katazyrna,Munoz-Espi Rafael,Guillemet Baptiste,Grohn Franziska The Polymer Society of Korea 2007 Macromolecular Research Vol.15 No.2

The most recent developments in two areas: (a) synthesis of inorganic particles with control over size and shape by polymer additives, and (b) synthesis of inorganic-polymer hybrid materials by bulk polymerization of blends of monomers with nanosized crystals are reviewed. The precipitations of inorganics, such as zinc oxide or calcium carbonate, in presence and under the control of bishydrophilic block or comb copolymers, are relevant to the field of Biomineralization. The application of surface modified latex particles, used as controlling agents, and the formation of hybrid crystals in which the latex is embedded in otherwise perfect crystals, are discussed. The formation of nano sized spheres of amorphous calcium carbonate, stabilized by surfactant-like polymers, is also discussed. Another method for the preparation of nanosized inorganic functional particles is the controlled pyrolysis of metal salt complexes of poly(acrylic acid), as demonstrated by the syntheses of lithium cobalt oxide and zinc/magnesium oxide. Bulk polymerization of methyl methacrylate blends, with for example, nanosized zinc oxide, revealed that the mechanisms of tree radical polymerization respond to the presence of these particles. The termination by radical-radical interaction and the gel effect are suppressed in favor of degenerative transfer, resulting in a polymer with enhanced thermal stability. The optical properties of the resulting polymer-particle blends are addressed based on the basic discussion of the miscibility of polymers and nanosized particles.

Polymers and Inorganics

Gerhard Wegner,Mustafa M. Demir,Michael Faatz,Katazyrna Gorna,Rafael Munoz Espi,Baptiste Guillemet,Franziska Grohn 한국고분자학회 2007 Macromolecular Research Vol.15 No.2

Reformulation of Multi uid Plasma Equations in Terms of Spacetime Algebra

S¨uleyman Demir,Murat Tanisli,Neslihan Sahin,Mustafa Emre Kansu 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.5

Using the exact isomorphism between multi uid plasma theory and classical electromagnetism, we apply the theorems and techniques of spacetime algebra to the multi uid equations of a plasma in order to present a new formulation in a compact and elegant way. A set of Maxwell equations for a plasma is combined into a single equation similar to their counterparts in electromagnetism, linear gravitation and uid mechanics. The presented formulation also proposes a useful method for the generalization of the plasma wave equation.