Synthesis of baghdadite using modified sol–gel route and investigation of its properties for bone treatment applications

Jodati Hossein,Tezcaner Ayşen,Evis Zafer,Alshemary Ammar Z,Çelik Erdal 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.2

The requirement for biomaterials with superior properties, used in bone treatment applications, is inevitable due to escalated bone tissue defects. Baghdadite (BAG) is a calcium silicate that benefits from the presence of zirconium (Zr) in its structure and has attracted huge attention in recent years. In this study, a modified sol–gel route was proposed to synthesize BAG by dissolving Zr precursor separately and using optimum amounts of solvent and chelating agent. Due to thermal gravimetric analysis and differential thermal analysis (TGA–DTA), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) results, the BAG nanoparticles were successfully synthesized using this modified approach for the first time, and they were comprehensively characterized in terms of physicochemical, mechanical, and biological properties. During synthesis, a transparent sol without any insoluble Ca or Zr precursors and/or no premature gelation was observed, unlike samples that we produced using the conventional sol–gel method in the literature. The crystalline BAG nanoparticles with semi-spherical shapes demonstrated ~ 20% weight loss after 28 days during the biodegradability test, extensive bioactivity, and enhanced mechanical strength (~4 MPa). Moreover, BAG powder was biocompatible with no cytotoxic effect and osteoinductive in the absence of an osteogenic medium. We believe that the synthesized BAG nanoparticles through this modified sol–gel route could serve as a promising biomaterial for cancellous bone defect treatment applications.

Brown Tumor of the Thoracic Spine : First Manifestation of Primary Hyperparathyroidism

Sonmez, Erkin,Tezcaner, Tugan,Coven, Ilker,Terzi, Aysen The Korean Neurosurgical Society 2015 Journal of Korean neurosurgical society Vol.58 No.4

Brown tumors also called as osteoclastomas, are rare nonneoplastic lesions that arise in the setting of primary or secondary hyperparathyroidism. Parathyroid adenomas or hyperplasia constitute the major Brown tumor source in primary hyperparathyroidism while chronic renal failure is the leading cause in secondary hyperparathyroidism. Most of the patients with the diagnosis of primary hyperparathyroidism present with kidney stones or isolated hypercalcemia. However, nearly one third of patients are asymptomatic and hypercalcemia is found incidentally. Skeletal involvement such as generalized osteopenia, bone resorption, bone cysts and Brown tumors are seen on the late phase of hyperparathyroidism. The symptoms include axial pain, radiculopathy, myelopathy and myeloradiculopathy according to their locations. Plasmocytoma, lymphoma, giant cell tumors and metastates should be ruled out in the differential diagnosis of Brown tumors. Treatment of Brown tumors involve both the management of hyperparathyroidism and neural decompression. The authors report a very rare spinal Brown tumor case, arisen as the initial manifestation of primary hyperparathyroidism that leads to acute paraparesis.

Human Papillomavirus Genotype Distribution and E6/E7 Oncogene Expression in Turkish Women with Cervical Cytological Findings

Tezcan, Seda,Ozgur, Didem,Ulger, Mahmut,Aslan, Gonul,Gurses, Iclal,Serin, Mehmet Sami,Giray, Burcu Gurer,Dilek, Saffet,Emekdas, Gurol Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.9

Background: Infection with certain human papillomavirus (HPV) genotypes is the most important risk factor related with cervical cancer. The objective of the present study was to investigate the prevalence of HPV infection, the distribution of HPV genotypes and HPV E6/E7 oncogene mRNA expression in Turkish women with different cervical cytological findings in Mersin province, Southern Turkey. Materials and Methods: A total of 476 cytological samples belonging to women with normal and abnormal cervical Pap smears were enrolled in the study. For the detection and genotyping assay, a PCR/direct cycle sequencing approach was used. E6/E7 mRNA expression of HPV-16, 18, 31, 33, and 45 was determined by type-specific real-time NASBA assay (NucliSENS EasyQ$^{(R)}$HPV v1.1). Results: Of the 476 samples, 106 (22.3%) were found to be positive for HPV DNA by PCR. The presence of HPV was significantly more common (p<0.001) in HSIL (6/8, 75%) when compared with LSIL (6/14, 42.9%), ASC-US (22/74, 29.7%) and normal cytology (72/380, 18.9%). The most prevalent genotypes were, in descending order of frequency, HPV genotype 66 (22.6%), 16 (20.8%), 6 (14.2%), 31 (11.3%), 53 (5.7%), and 83 (4.7%). HPV E6/E7 oncogene mRNA positivity (12/476, 2.5%) was lower than DNA positivity (38/476, 7.9%). Conclusions: Our data present a wide distribution of HPV genotypes in the analyzed population. HPV genotypes 66, 16, 6, 31, 53 and 83 were the predominant types and most of them were potential carcinogenic types. Because of the differences between HPV E6/E7 mRNA and DNA positivity, further studies are required to test the role of mRNA testing in the triage of women with abnormal cervical cytology or follow up of HPV DNA positive and cytology negative. These epidemiological data will be important to determine the future impact of vaccination on HPV infected women in our region.

Periodic solutions of the Duffing equation

Tezcan, Jale,Hsiao, J. Kent Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.5

This paper presents a new linearization algorithm to find the periodic solutions of the Duffing equation, under harmonic loads. Since the Duffing equation models a single degree of freedom system with a cubic nonlinear term in the restoring force, finding its periodic solutions using classical harmonic balance (HB) approach requires numerical integration. The algorithm developed in this paper replaces the integrals appearing in the classical HB method with triangular matrices that are evaluated algebraically. The computational cost of using increased number of frequency components in the matrixbased linearization approach is much smaller than its integration-based counterpart. The algorithm is computationally efficient; it only takes a few iterations within the region of convergence. An example comparing the results of the linearization algorithm with the "exact" solutions from a 4th order Runge- Kutta method are presented. The accuracy and speed of the algorithm is compared to the classical HB method, and the limitations of the algorithm are discussed.

Carpal Tunnel Syndrome in Patients with Psoriatic Arthritis: Ultrasonography and Magnetic Resonance Imaging Findings

Tezcan Ezgi Akyildiz,Levendoglu Funda,Durmaz Mehmet Sedat,Kara Hasan,Batur Elif Balevi,Gezer Ilknur Albayrak,Korez Muslu Kazım 대한류마티스학회 2023 대한류마티스학회지 Vol.30 No.1

Objective: The aim of the present study is to assess carpal tunnel syndrome's (CTS’s) ultrasonography (US) and magnetic resonance imaging (MRI) findings in patients with psoriatic arthritis (PsA) and compare them with healthy controls. Methods: Thirty-nine PsA and twenty-eight healthy volunteers were examined in this study. Demographic and clinical features were recorded. CTS-6, a diagnostic algorithm, was used to estimate the probability of CTS. Electrodiagnostic study (EDS) was applied to all wrists included in the report, where the diagnosis of CTS was made by EDS. The cross-sectional area (CSA) of the median nerve was measured at pisiform bone level by US and MRI. Results: Regarding to the demographic characteristics, no statistically significant difference was found between the groups. Twelve of 39 (30.76%) PsA patients had CTS, whereas CTS was not detected in the control group (p=0.001). US and MRI showed increased median nerve CSA in PsA patients compared to healthy controls (p=0.005, p<0.001; respectively). Also, US and MRI showed increased median nerve CSA in CTS patients compared to others (p=0.002, p<0.001; respectively). The Pearson correlation coefficient between MRI and US measurements of the CSA was 0.85 (p<0.001). Conclusion: CTS frequency in PsA patients is found higher than healthy controls. The relationship between CTS diagnosed by EDS and CSA measured by both US and MRI was observed in PsA patients.

Periodic solutions of the Duffing equation

Jale Tezcan,J. Kent Hsiao 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.5

This paper presents a new linearization algorithm to find the periodic solutions of the Duffing equation, under harmonic loads. Since the Duffing equation models a single degree of freedom system with a cubic nonlinear term in the restoring force, finding its periodic solutions using classical harmonic balance (HB) approach requires numerical integration. The algorithm developed in this paper replaces the integrals appearing in the classical HB method with triangular matrices that are evaluated algebraically. The computational cost of using increased number of frequency components in the matrixbased linearization approach is much smaller than its integration-based counterpart. The algorithm is computationally efficient; it only takes a few iterations within the region of convergence. An example comparing the results of the linearization algorithm with the “exact” solutions from a 4th order Runge- Kutta method are presented. The accuracy and speed of the algorithm is compared to the classical HB method, and the limitations of the algorithm are discussed.

Effect of Surface Pre-treatments and Ageing on the Adhesive Strength of Polymer Joints

Sidem Kaner,Tezcan Sekercioglu 한국고분자학회 2017 폴리머 Vol.41 No.5

In this study, the effects of pre-treatment and ageing on the adhesive strength of polymer materials PE, PP and PVC are investigated experimentally. The experiments are carried out under mechanical abrasion, corona discharge and plasma methods at temperatures of -20, 0, 20℃ and ageing for different times for 30, 60, 90 days at 50℃. The shear stress increased for PVC at -20℃, using both corona discharge and plasma methods. The shear strength of adhesively bonded joints reduced at an ageing temperature of 50℃ and it continued to gradually reduce during ageing time from 30 to 90 days. The lowest strength was obtained at 50℃ and 90 days’ ageing.

Piriformis syndrome as an overlooked cause of pain in a patient with axial spondyloarthritis: a case report

( Ezgi Akyildiz Tezcan ),( Kemal Erol ),( Ilknur Albayrak Gezer ) 대한류마티스학회 2024 대한류마티스학회지 Vol.31 No.2

Piriformis syndrome is a neuromuscular disorder characterized by hip, buttock, and leg pain. Axial spondyloarthritis is a rheumatic disease primarily affecting the sacroiliac joint and the spine. Due to their anatomical proximity, the potential relationship between piriformis syndrome and sacroiliitis has been discussed for some time. However, literature review revealed that there is no study on piriformis syndrome in individuals with axial spondyloarthritis. Here, we present the case of a 30-year-old female with axial spondyloarthritis who developed severe low back, hip, and buttock pain that persisted despite initial treatment for axial spondyloarthritis. We first re-evaluated her condition through physical examination, magnetic resonance imaging, and an injection test for piriformis syndrome. Following a comprehensive assessment, the patient was diagnosed with both axial spondyloarthritis and piriformis syndrome. Subsequently, a tailored treatment plan was devised, addressing both conditions, and after a 3-month course of treatment, we obtained significant reduction in pain of the patient. This is the first case report in literature, where we used injection test to confirm the diagnosis of the piriformis syndrome in a patient with axial spondyloarthritis. We therefore strongly advocate considering piriformis syndrome as a potential etiology for pain in individuals with axial spondyloarthritis consistently. This recognition is important as piriformis syndrome does not respond adequately to non-steroidal antiinflammatory drugs and may lead to unnecessary use of biological disease-modifying antirheumatic drugs. Timely identification and intervention are imperative in ensuring optimal patient care.

Strengthening of RC beams with prefabricated RC U cross-sectional plates

Ali Demir,Muhammed Tekin,Tezcan Turalı,Muhiddin Bagci 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.6

The topic of this study is to strengthen cracked beams with prefabricated RC U cross-sectional plates. The damaged beams were repaired by epoxy based glue. The repaired beams were strengthened using prefabricated plates. The strengthening plates were bonded to the bottom and side faces of the beams by anchorage rods and epoxy. The strengthened beams were incrementally loaded up to maximum load capacities. The experimental results were satisfactory since the load carrying capacities of damaged beams were increased approximately 76% due to strengthening. It was observed that strengthening plates had a dominant effect on the performance of beams in terms of both the post-elastic strength enhancement and the ductility. The experimental program was supported by a three-dimensional nonlinear finite element analysis. The experimental results were compared with the results obtained from the beam modeled with ANSYS finite element program.

Genome-wide identification and comperative analysis of RuBisCo genes/proteins in Asteracea

Murat Kemal Avci,Erdem Tezcan,Emre Sevindik 한국원예학회 2016 Horticulture, Environment, and Biotechnology Vol.57 No.4

Asteraceae, the largest known plant family in the world, contains economically important species including ornamental plants. The most abundant enzyme on Earth, Ribulose-1,5-bisphosphate (RuBisCo), catalyzes the first stepof carbon assimilation in photosynthesis. In this study, we conducted sequence, physicochemical, phylogenetic, and three-dimensional comparative analyses of 22 RuBisCo proteins in the Asteraceae using various bioinformatic tools. The alignment results showed that all residues corresponding to the region between 48-179 amino acids were conserved in all species, except for just seven residues: G79, I80, S88, F90, F93, I135, and S136. The sequence lengths of the RuBisCo large subunits were between 163 and 477 amino acids, with an average length of 255 amino acids. Their molecular weights (Mw) ranged from 18341.8 to 52895.1 Da, with an average Mw of 26294.5 Da. We found that the most abundant amino acid residue was Gly, which comprised 9.88% of these RuBisCo proteins. Ala (8.17%) and Leu (8.53%) were also both abundant. The extinction coefficient of the RuBisCo proteins at 280 nm ranged from 27515 to 69830 M-1 cm-1. The instability index values ranged from 24.41 to 40.65, and only one protein (from Gymnarrhena micrantha) was unstable in vitro. The aliphatic index values ranged from 72.56 to 81.13, while the GRAVY values ranged from -0.394 to -0.179. A total of ten motifs were identified in the sequences of the RuBisCo proteins. Phylogenetic analysis revealed that the 22 RuBisCo proteins formed two main clades. A RAMPAGEanalysis revealed that 95.0-98.4% of residues were located in the favored region in 22 RuBisCo proteins. Sequence alignment and 3D analysis revealed that a catalytically important Lys residue was conserved among all the RuBisCoenzymes of Asteraceae. The results of this study provide insights into the fundamental characteristics of the RuBisCo proteins of the Asteraceae.