Effect of yttria on thermal stability, mechanical and in vitro bioactivity properties of hydroxyapatite/alumina composite

Serdar PAZARLIOĞLU,Serdar SALMAN 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.1

The phase stability, mechanical and in vitro bioactivity properties of hydroxyapatite/alumina composite with and withoutyttria were investigated. Hydroxyapatite without additives decomposed at 1300 oC to beta- and alpha-tricalcium phosphateand calcium oxide phases. Although alumina contributed to the mechanical properties of hydroxyapatite, it not only decreasedthe decomposition temperature of hydroxyapatite from 1200 oC to 900 oC and it’s in vitro bioactivity property but alsoincreased the decomposition ratio of hydroxyapatite. An improvement in the properties of hydroxyapatite/alumina compositewas provided by yttria via inhibiting the solid-state reactions between hydroxyapatite and alumina via the formation of yttriumaluminum oxide and calcium yttrium trialuminum oxide phases. The maximum fracture toughness of 2.178 ± 0.251 MPam1/2,microhardness of 4.947 ± 0.191 GPa, a compressive strength of 227.75 ± 27.87 MPa, and a three-point bending strength of90.15 ± 6.93 MPa were achieved for hydroxyapatite/alumina composite containing 1.5 wt% yttria at the sintering temperatureof 1200 oC. The relative density of 92.94 ± 0.11% was also attained. This ternary composite can potentially be used in thehuman body for load-bearing applications because of its sufficient mechanical and in vitro bioactivity properties with adecomposition ratio of 9.4%.

Optimum Sizing Design of Steel Frame Structures Using Evaporation Rate-Based Water Cycle Algorithm with Greedy Selection

Serdar Carbas 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.4

The evaporation rate-based water cycle algorithm (WCA-ER) is one of the famous nature-inspired metaheuristic optimization methods asserted to simulate principal idea behind observation of water cycle process with evaporation rate where how rivers and streams fl ow to the sea. In WCA-ER, an evaporation rate notion was identifi ed formatively to standard WCA for achieving a better balance between the exploration and exploitation phases. This enables making better choice decision. Furthermore, in this study the WCA-ER is equipped with a greedy selection scheme bringing about much effi cient search technique for obtaining the optimal designs by maintaining solution diversity and enhancing the exploitation phase. So, the main objective of this paper is to attain optimal sizing designs of both planar and space steel frame structures using WCA-ER with greedy selection. In this context, the WCA-ER with greedy selection choses the W steel sections to assign the member groups treated as design variables. Not only the strength and stability constraints imposing from LRFD-AISC code of practice design, but also the defl ection, drift, and geometric constraints are taken into account in design optimization. The optimally frame designs obtained by WCA-ER with greedy selection are tabulated and they are compared with previously reported optimum solutions via other metaheuristic algorithms. The achieved best feasible steel frame structures for design examples illustrate the robustness and effi ciency of the algorithmic performance of the WCA-ER with greedy selection.

Active structural control via metaheuristic algorithms considering soil-structure interaction

Serdar Ulusoy,Gebrail Bekdaş,Sinan Melih Nigdeli 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.2

In this study, multi-story structures are actively controlled using metaheuristic algorithms. The soil conditions such as dense, normal and soft soil are considered under near-fault ground motions consisting of two types of impulsive motions called directivity effect (fault normal component) and the flint step (fault parallel component). In the active tendon-controlled structure, Proportional–Integral–Derivative (PID) type controller optimized by the proposed algorithms was used to achieve a control signal and to produce a corresponding control force. As the novelty of the study, the parameters of PID controller were determined by different metaheuristic algorithms to find the best one for seismic structures. These algorithms are flower pollination algorithm (FPA), teaching learning based optimization (TLBO) and Jaya Algorithm (JA). Furthermore, since the influence of time delay on the structural responses is an important issue for active control systems, it should be considered in the optimization process and time domain analyses. The proposed method was applied for a 15-story structural model and the feasible results were found by limiting the maximum control force for the near-fault records defined in FEMA P-695. Finally, it was determined that the active control using metaheuristic algorithms optimally reduced the structural responses and can be applied for the buildings with the soil-structure interaction (SSI).

Dandy Walker Variant and Bipolar I Disorder with Graphomania

Serdar Suleyman Can,Gorkem Karakas Ugurlu,Selcen Cakmak 대한신경정신의학회 2014 PSYCHIATRY INVESTIGATION Vol.11 No.3

Cerebellum is known to play an important role in coordination and motor functions. In some resent studies it is also considered to be involved in modulation of mood, cognition and psychiatric disorders. Dandy Walker Malformation is a congenital malformation that is characterized by hypoplasia or aplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle and enlargement of the posterior fossa. When the volume of posterior fossa is normal, the malformation is called Dandy Walker Variant. Case is a 32 year old male with a 12 year history of Bipolar I Disorder presented with manic and depresive symptoms, including dysphoric and depressive affect, anhedonia, suicidal thoughts and behaviours, thoughts of fear about future, overtalkativeness and graphomania, increased energy, irregular sleep, loss of appetite, increased immersion in projects, irritability, agressive behavior, impulsivity. Cranial Magnetic Resonance Imaging was compatible to the morphological features of Dandy Walker Variant.

A Case of Ileus in a Patient with Schizophrenia Under Paliperidone Palmitate Treatment

Serdar Süleyman Can,Esra Kabadayı 대한신경정신의학회 2016 PSYCHIATRY INVESTIGATION Vol.13 No.6

Constipation is a side effect of antipsychotic drugs that have high affinity for muscarinic cholinergic receptors. In addition, ileus is an important side effect of antipsychotic treatment, with potentially morbid and mortal consequences if early detection fails. In this report, a colonic ileus case is described in a patient with schizophrenia under the treatment of paliperidone palmitate. Consequently, complete physical examination and close screening of side effects are recommended when antipsychotics are prescribed.

The gastronomic cultures' impact on the African cuisine

Serdar Oktay,Saide Sadıkoglu 한국식품연구원 2018 Journal of Ethnic Foods Vol.5 No.2

Background: The countries of the African continent have had centuries of European colonial rule. Historically, African countries have been influenced by gastronomic cultures of the colonial European countries and eventually developed their own gastronomic culture. Every country has adopted a different food culture from a neighboring society and every society has taken the food culture from those who migrated from far away countries. Methods: In this study, literature search was carried out on the gastronomic cultures transferred to African cuisines. Zimbabwe in the west, Nigeria in the east, Morocco in the north and Republic of South Africa in the south were selected for the research. Scientific researches, articles, graduate theses, printed scientific books and historical documents were examined for this study. Results: We see that African countries still use the culinary culture they received from the European civilizations they lived in the past years. Conclusion: The foods that they have transferred to their own country's culinary cultures still continue to be consumed with fondness. Historical relations play a very important role when evaluating the country kitchens.

Comparison and efficacy of two different sheep pox vaccines prepared from the Bakırköy strain against lumpy skin disease in cattle

Serdar Uzar 대한백신학회 2022 Clinical and Experimental Vaccine Research Vol.11 No.1

Purpose: Lumpy skin disease (LSD) is a highly contagious and economically important viral infection of cattle, which leads to financial losses in the livestock industry of affected countries. Vaccination is the most effective control measure to prevent the disease. Heterologous sheep pox (SP) vaccine was used against LSD in Turkey. In this research, it was aimed to adapt SP Bakırköy vaccine strain attenuated in lamb kidney cells to Madin-Darby bovine kidney (MDBK) cells to provide better protection than commercial SP vaccine in cattle. Materials and Methods: To evaluate safety and efficacy of vaccines, while animals were immunized with 10 doses (104.75 50% tissue culture infectious dose [TCID50]) and 5 doses of SP vaccine (104 TCID50) produced in MDBK cells, others were immunized with commercial Penpox-M vaccine (103.9 TCID50). Two cattle were kept as unvaccinated. At day 31 post-vaccination, all animals were challenged with the virulent LSD virus. Blood and swab samples were taken on certain days post-inoculation. Logarithmic differences challenge virus titers between vaccinated and unvaccinated animals were calculated. Results: The clinical sign was not observed in animals immunized with 10 doses of SP vaccine. The differences between the animals immunized with SP vaccine and control group was less than log 2.5 and the viremia occurred in immunized animals. The difference in titer was higher than log 2.5 in animals immunized with the Penpox-M, and viremia did not occur. Conclusion: SP vaccine strain propagated in MDBK cells and can be used for immunization to prevent LSD infections. However, SP vaccine strain propagated in MDBK showed poor protection as compared to Penpox-M

Are There Relationships between Seminal Parameters and the Neutrophil-to-Lymphocyte Ratio or the Platelet-to-Lymphocyte Ratio?

Serdar Aykan,Lütfi Canat,Serkan Gönültaş,Hasan Anıl Atalay,Fatih Altunrende 대한남성과학회 2017 The World Journal of Men's Health Vol.35 No.1

Purpose: The aim of this study was to evaluate the relationship of seminal parameters with the neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR), which are inflammatory markers, in men with an abnormal semen analysis and men with normozoospermia.Materials and Methods: Fifty-seven men with abnormal semen analyses and 59 men with normozoospermia were included in this cross-sectional study. A complete blood count was recorded, and the NLR and PLR were calculated from the hematologic parameters.Results: The NLR was 1.84±0.78 in the normozoospermic group and 1.80±0.75 in the abnormal semen analysis group. The PLR was 95.32±35.47 in the normozoospermic group and 93.57±28.09 in the abnormal semen analysis group. No significant differences were found between the normozoospermic and the abnormal semen analysis group in the NLR (p=0.828) or the PLR (p=0.768). In addition, no seminal parameters were correlated with the NLR or the PLR (p>0.05).Conclusions: We do not recommend using the NLR or the PLR as markers to screen for abnormal semen parameters or male infertility.

Publication Trends in the Pelvic Parameter Related Literature between 1992 and 2022 : A Bibliometric Review

Serdar Yüksel,Emre Özmen,Alican Barış,Esra Circi,Ozan Beytemür 대한신경외과학회 2024 Journal of Korean neurosurgical society Vol.67 No.1

Objective : This study aimed to conduct a bibliometric analysis on pelvic parameter related research over the last 30 years, analyzing trends, hotspots, and influential works within this field. Methods : A comprehensive Web of Science database search was performed. The search yielded 3249 results, focusing on articles and reviews published from 1992 to 2022 in English. Data was analyzed using CiteSpace and VOSviewer for keyword, authorship, and citation burst analysis, co-citation analysis, and clustering. Results : The number of publications and citations related to pelvic parameters has increased exponentially over the last 30 years. The USA leads in publication count with 1003 articles. Top publishing journals include the European Spine Journal, Spine, and Journal of Neurosurgery: Spine, with significant contributions by Schwab, Lafage V, and Protoptaltis. The most influential articles were identified using centrality and sigma values, indicating their role as key articles within the field. Research hotspots included spinal deformity, total hip arthroplasty, and sagittal alignment. Conclusion : Interest in pelvic parameter related research has grown significantly over the last three decades, indicating its relevance in modern orthopedics. The most influential works within this field have contributed to our understanding of spinal deformity, pelvic incidence, and their relation to total hip arthroplasty. This study provides a comprehensive overview of the trends and influential research in the field of pelvic parameters.

Comparison of Safety Perception between Foreign and Local Workers in the Construction Industry in Republic of Korea

Serdar Korkmaz,박달재 한국산업안전보건공단 산업안전보건연구원 2018 Safety and health at work Vol.9 No.1

Background: Since the Republic of Korea became a labor-force-importing country, the number of foreign workers has increased gradually, especially in the construction industry. The main objective of this study was to examine the differences in safety perception between domestic and foreign workers at Korean construction sites. Methods: A total of 891 Korean and foreign workers were surveyed: 140 foreign and 751 Korean workers. The general characteristics and 25 factors influencing safety perception were considered in the questionnaire. Regression and correlation analyses were conducted to examine the variables of workers’ safety perception. Results: Differences of nationality (F ¼ 7.379, p < 0.001) and workplace accidents were statistically significant for both domestic (F ¼ 1.503, p < 0.05) and foreign workers (F ¼ 7.868, p < 0.05). In contrast, age, education, and Korean language level were significant variables only for foreign workers. Correlation coefficients of 0.428** for Korean and 0.148 for foreign workers between two items e namely, “management’s commitment to safety” and “blaming staff when they make mistakes” e support the conclusion that foreign workers do not trust management’s commitment to safety, while Korean workers have confidence in these commitments. Conclusion: Foreign workers’ level of safety perception should rise to the same level as Korean workers, especially in terms of obeying safety rules, safety education performance, and safety beliefs. Therefore, an improvement plan for the Korean construction industry is suggested in order to have a better safety level at construction sites with foreign workers.