Application of the full factorial design to modelling of Al₂O₃/SiC particle reinforced al-matrix composites

Necat Altinkok 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.6

Al₂O₃/SiC particulate reinforced (Metal Matrix Composites) MMCs which were produced by using stir casting process, bending strength and hardening behaviour were obtained using an analysis of variance (ANOVA) technique that uses full factorial design. Factor variables and their ranges were: particle size 2-60 <i>μ</i>m; the stirring speed 450 rpm, 500 rpm and the stirring temperature 620°C, 650°C. An empirical equation was derived from test results to describe the relationship between the test parameters. This model for the tensile strength of the hybrid composite materials with <i>R</i>² adj = 80% for the bending strength <i>R</i>² adj = 89% were generated from the data. The regression coefficients of this model quantify the tensile strength and bending strengths of the effects of each of the factors. The interactions of all three factors do not present significant percentage contributions on the tensile strength and bending strengths of hybrid composite materials. Analysis of the residuals versus was predicted the tensile strength and bending strengths show a normalized distribution and thereby confirms the suitability of this model. Particle size was found to have the strongest influence on the tensile strength and bending strength.

CHARACTERIZATION OF CENTRAL UNITS OF ZAn

Tevfik Bilgin,Necat Gorentas,I. Gokhan Kelebek 대한수학회 2010 대한수학회지 Vol.47 No.6

The structure of V (Z(ZAn)) is known when n ≤ 6. If n = 5or 6, then a complete set of generators of V (Z(ZAn)) has been deter-mined. In this study, it was shown that V (Z(ZAn)) is trivial when n = 7; 8 or 9 and it is generated by a single unit u when n = 10 or 11: This unit u is characterized explicitly for n = 10 or 11 by using irreducible characters of An.

CHARACTERIZATION OF CENTRAL UNITS OF ℤA_n

Bilgin, Tevfik,Gorentas, Necat,Kelebek, I. Gokhan Korean Mathematical Society 2010 대한수학회지 Vol.47 No.6

The structure of V(Ƶ($ZA_n$)) is known when $n\leq6$. If n = 5 or 6, then a complete set of generators of V (Ƶ($ZA_n$)) has been deter-mined. In this study, it was shown that V (Ƶ($ZA_n$)) is trivial when n = 7, 8 or 9 and it is generated by a single unit u when n = 10 or 11: This unit u is characterized explicitly for n = 10 or 11 by using irreducible characters of $A_n$.

HDL-Associated Paraoxonase 1 as a Bridge between Postmenopausal Osteoporosis and Cardiovascular Disease

Esin Eren,Hamit Yasar Ellidag,Necat Yılmaz,Ozgur Aydin 전남대학교 의과학연구소 2014 전남의대학술지 Vol.50 No.3

The association of postmenopausal osteoporosis (PMOP) with both atherosclerosis and vascular/valvular calcification is well known. Recently, ample evidence has suggested a common etiologic factor, namely, reduced HDL-associated paraoxonase 1 (PON1) activity, as a causative factor in the development of PMOP and cardiovascular disease (CVD). This common etiologic factor not only contributes to atherosclerotic diseases but also to PMOP following an almost identical mechanism including dysfunctional HDL and lipid oxidation. According to recent studies, lipid oxidation might improve osteoblastic transformation of vascular cells and obstruct such transformation in bone cells. The primary objective of this current review was to summarize the evidence revealing the role of HDL-associated PON1 enzyme in PMOP. Additionally, the review aimed to address some of the subjects that need further investigation in order to define whether hyperhomocysteinemia and sensitivity to lipid oxidation may be risk factors for PMOP.

Decreased HDL-Dependent Paraoxonase and Arylesterase Enzyme Activity May Indicate a Worse Prognosis in Multiple Myeloma

Ellidag, Hamit Yasar,Aydin, Ozgur,Eren, Esin,Yilmaz, Necat,Ergin, Merve Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

Background: Multiple myeloma (MM) is a haematological cancer characterized by clonal proliferation of plasma cells.The aim of this study was to investigate the activity of serum paraoxonase-1 (PON1) and arylesterase (ARE) in multiple myeloma with and without free light chain excretion(FLCe-MM and NFLCe-MM); as well as to investigate possible alterations in oxidative stress parameters. Materials and Methods: Total thiol (T.thl), oxidative stress index (OSI), total oxidant status (TOS) and total antioxidant status (TAS) were examined in addition to the PON1 and ARE enzyme activities in twenty one FLCe-MM and nineteen NFLCe-MM subjects. Routine parameters like lipid panel, serum total protein, albumin, creatinine, blood urea nitrogen (BUN), uric acid and hemoglobin levels were compared with the oxidative stress markers. Results: Serum total protein, BUN, creatinin, and uric acid levels were significantly higher (p=0.04, p=0.001, p=0.001 and p=0.0022, respectively), while hemoglobin and albumin levels were significantly lower in FLCe-MM patients (p=0.009 and p=0.04,respectively). PON1 and ARE activities were significantly lower in patients with FLCe-MM compared to those with NFLCe-MM (p=0.001 and p=0.008, respectively). Conclusions: Depending on our results of prognostic markers of MM such as age, hemoglobin, albumin, and creatinine we feel confident to presume FLCe-MM as a subgroup with a worse prognosis. A decrease in PON1 and ARE activities may contribute to the prognosis and may be used as a prognostic tool in MM.

Ischemia Modified Albumin Levels and Oxidative Stress in Patients with Bladder Cancer

Ellidag, Hamit Yasar,Eren, Esin,Aydin, Ozgur,Akgol, Evren,Yalcinkaya, Soner,Sezer, Cem,Yilmaz, Necat Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.5

Background: Impaired oxidative/antioxidative status plays an important role in the pathogenesis of many diseases like cancer. The aim of this study was to evaluate the levels of the novel marker ischemia modified albumin (IMA) and albumin adjusted-IMA (Adj-IMA) in patients with bladder cancer (BC) as well as its association with total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI). Materials and Methods: Forty male patients with BC (mean age, $67.4{\pm}12$ years) and forty age-sex matched healthy persons (mean age $56.0{\pm}1.7$ years) were included in this study. Serum levels of IMA, TAS, TOS were analyzed and Adj- IMA and OSI was calculated. Results: Serum IMA, TOS and OSI values were significantly higher in patients with BC compared to controls (p<0.0001, p=0.01 and p=0.01, respectively), whereas TAS was significantly lower in BC patients (p=0.04). There was no significant difference for serum albumin-adjusted IMA levels between groups (p=0.4). Conclusions: In this study, it was found that there was an impaired oxidative/antioxidant status in favor of oxidative stress in BC patients. This observation was not confirmed by Adj-IMA calculation. There is no published report about serum concentrations of IMA in patients with BC. Further studies are needed to establish the relationship of IMA and oxidative stress parameters in BC and the significance of IMA to other cancers.

Tumour Markers in Peritoneal Washing Fluid - Contribution to Cytology

Yildirim, Mustafa,Suren, Dinc,Yildiz, Mustafa,Alikanoglu, Arsenal Sezgin,Kaya, Vildan,Doluoglu, Suleyman Gunhan,Aydin, Ozgur,Yilmaz, Necat,Sezer, Cem,Karaca, Mehmet Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

Background: Peritoneal washing cytology (PWC) that shows the microscopic intra-peritoneal spread of gynaecologic cancers is not used in staging but is known as prognostic factor and effective in planning the intensity of the therapy. False negative or false positive results clearly affect the ability to make the best decision for therapy. In this study we assessed levels of tumour markers, carcinoembryonic antigen (CEA), cancer antigen 125 (CA-125) and carbohydrate antigen (CA19-9), in peritoneal washing fluid to establish any possible contribution to the peritoneal washing cytology in patients operated for gynaecologic cancer. Materials and Methods: Preoperative tumour markers were studied in serum of blood samples obtained from the patients for preoperative evaluation of a gynaecologic operation. In the same group peritoneal tumour markers were studied in the washing fluid obtained for intraoperative cytological evaluation. Results: This study included a total of 94 patients, 62 with malignant and 32 with benign histopathology. The sensitivity of the cytological examination was found to be 21% with a specificity of 100%. When evaluated with CEA the sensitivity of the cytological examination has increased to 37%. Conclusions: In addition to examination of PWC, the level of CEA, a tumour marker, in peritoneal washing fluid can make a diagnostic contribution. Determining the level of CEA in peritoneal washing fluid will be useful in the management of gynaecologic cancers.

Poster Session : PS 0462 ; Genetics ; Different Effects of Polymorphisms in HLA-DR Locus are Possible Between Females and Males in the Development of Graves` Disease

( E Sacide Kozan ),( Salih Kozan ),( Yalcin Aral ),( Ahmet Yildirim ),( Mesut Akyol ),( Zafer Aydin Ecemis ),( Necat Imirzalioglu ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Graves` disease is more prevalent in women. HLA-DR locus, an immune response genes, is well-studied in different populations, but the difference in distributions of succestibility alleles between females and males are required to be clarifi ed. Methods: Totally 140 subjects consisting of 70 patients with Graves` disease (GD) (44 females, 26 males) and 70 controls (55 females, 15 males) were included to the study. Thirteen polymorphisms for DRB1 with DRB3, DRB4 and DRB5 were analysed by PCRSSP method. The difference in distributions of DR alleles were compared between females and males. A study model was designed for confi rming of Results: Results: None of DR polimorphisms, in existance or absence of alleles, was associated with GD among males. However, in absence of DRB1*07, GD risk was higher than the carriage of at least one allele in females (p=0.012, OR=9.56). In addition, the development of GD risk among females was higher in the carriage of at least one DRB1*15 allele (p=0.004, OR=4.67). Carriage of DRB5 was also found in association with GD among females with suggestive risk (p=0.003, OR=4.07). However, underlying cause of the risk was unclear due to the haplotype inheritance of DRB1*15/ DRB5. Conclusions: We concluded that, gender is an effective factor on the evaluation of the association between DR polymorphisms and GD.

Roles for Paraoxonase but not Ceruloplasmin in Peritoneal Washing Fluid in Differential Diagnosis of Gynecologic Pathologies

Yildirim, Mustafa,Demirpence, Ozlem,Kaya, Vildan,Suren, Dinc,Karaca, Mehmet,Evliyaoglu, Osman,Yilmaz, Necat,Gunduz, Seyda Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.15

Background: Intraperitoneal spread of gynecologic cancers is a major cause of mortality and morbidity and often presents with malignant ascites. Microscopic tumor spread can be demonstrated by a peritoneal wash cytology and help assess the prognosis of the disease. In our study, the roles of paraoxonase and ceruloplasmin, measured in peritoneal washing fluid of patients operated for gynecologic pathologies in differential diagnosis was investigated. Materials and Methods: Patients operated for malign or benign gynecologic pathologies in Antalya Education and Research Hospital Gynecology Clinic between 2010-2012 were included in the study. Samples were obtained during surgery. Results: A statistically significant difference was detected between patients with benign and malign diseases with regards to PON1 levels measured in peritoneal washing fluid (p:0.044), the average values being $64.2{\pm}30.8$ (Range 10.8-187.2) and $41.4{\pm}21.4$ (Range 10.4-95.5), respectively. No significant variation was evident for ceruloplasmin. Conclusions: Paraoxonase levels measured in peritoneal washing fluid may contribute to the differentiation of malign-benign diseases in gynecologic pathologies.

ORiginal Article : Ischemia-Modified Albumin: Could It Be a New Oxidative Stress Biomarker for Colorectal Carcinoma?

( Hamit Yasar Ellidag ),( Nurullah Bulbuller ),( Esin Eren ),( Sedat Abusoglu ),( Evren Akgol ),( Mustafa Cetiner ),( Necat Yilma ) The Editorial Office of Gut and Liver 2013 Gut and Liver Vol.7 No.6

Background/Aims: An impaired oxidative/antioxidative status plays an important role in the pathogenesis of many diseases, including cancer. The aim of this study was to evaluate the levels of the novel marker ischemia-modified al-bumin (IMA) and albumin-adjusted IMA (Adj-IMA) in patients with colorectal cancer (CRC) and look for the associations of these with the total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI). Methods: Forty patients with CRC (19 females and 21 males; mean age, 56.5±2.1 years) and 39 age- and sex-matched healthy peo-ple (22 females and 17 males; mean age, 56.0±1.7 years) were included in this study. Serum levels of IMA, TAS, and TOS were analyzed, and the OSI was calculated. Results: Serum IMA, TOS, and OSI levels were significantly higher in patients with CRC than in controls (p<0.0001), whereas TAS levels were significantly lower in CRC patients (p=0.03). There was no significant difference in serum Adj-IMA levels between groups (p=0.32). Conclusions: In this study, the oxidative/antioxidant status was impaired in favor of oxida-tive stress in CRC patients. This observation was not con-firmed by IMA measurement. Further studies are needed to establish the relationship between IMA and oxidative stress parameters in CRC and other cancers. (Gut Liver 2013;7:675-680)