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Search Results: 1 - 10 of 19030 matches for " Ali Ayhan Tuncay "
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Understanding the Effects of Historic Land Use Pattern on an Urbanized Stream Corridor
Ali Ayhan Tuncay,Hayriye Esbah
Journal of Applied Sciences , 2006,
Abstract: This case study aims to understand the characteristics of the historic land use pattern in the surrounding areas of a streambed in Aydin, Turkey. Aerial photographs from 1960 and Ikonos images from 2002 are utilized in GIS environment. Two analytical approaches exist: (1) detecting the magnitude of growth in the urban area and (2) detecting the land use transformation along the streambed. Matrix Utility index is employed to relate the amount of imperviousness to each land use type. Overall, the City has expanded 80.14% and the matrix utility value dropped 25.30%, which mean that less compatible land uses surrounded the stream each coming year. The typical outcome of this trend is increasing high density with very high percentages of impervious surfaces. A new land use scenarios should be generated to bring the index value to its initial levels. In this aspect, the matrix utility index could be an effective tool in land use decisions and in developing common language between urban planners and landscape architects.
Dynamic Stabilization for Challenging Lumbar Degenerative Diseases of the Spine: A Review of the Literature
Tuncay Kaner,Ali Fahir Ozer
Advances in Orthopedics , 2013, DOI: 10.1155/2013/753470
Abstract: Fusion and rigid instrumentation have been currently the mainstay for the surgical treatment of degenerative diseases of the spine over the last 4 decades. In all over the world the common experience was formed about fusion surgery. Satisfactory results of lumbar spinal fusion appeared completely incompatible and unfavorable within years. Rigid spinal implants along with fusion cause increased stresses of the adjacent segments and have some important disadvantages such as donor site morbidity including pain, wound problems, infections because of longer operating time, pseudarthrosis, and fatigue failure of implants. Alternative spinal implants were developed with time on unsatisfactory outcomes of rigid internal fixation along with fusion. Motion preservation devices which include both anterior and posterior dynamic stabilization are designed and used especially in the last two decades. This paper evaluates the dynamic stabilization of the lumbar spine and talks about chronologically some novel dynamic stabilization devices and thier efficacies. 1. Introduction Today, low back pain is one of the most important problem in decreasing the quality of life as a result of lumbar disc degeneration [1–4]. It is thought that the origin of low back pain results from degenerative intervertebral disc and facet joints. Segmental instability significantly contributed to lower back pain. Instability associated with intervertebral disc degeneration is represented first by Knutsson in 1944 [5]. Knutsson also described the abnormal flexion-extention slipping in X-ray along with disc degeneration and told that segmental instability should be if sagittal slipping is greater than 3?mm in dynamic X-ray. Degeneration process of the lumbar spine and pathology of discogenic pain were described by Kirkaldy-Willis and Farfan in 1982 [2]. They explained that degenerative instability of the spine began primarily with disc degeneration which contains dehydration of intervertebral disc along with decrease in tension of the annulus fibrosis. It is followed by decrease of disc height, and then this process continues with hypertrophy of the facet joint and ligamentum flavum. At the end spinal stenosis and degenerative spondylolisthesis, which have caused low back pain, occur. Besides, Frymoyer and Selby revealed the concept of primary and secondary instabilities and put the degenerative disc disease, degenerative spondylolisthesis, and degenerative scoliotic deformities into the group of primary instability [6, 7]. Panjabi also well defined the term instability that leads to a pain,
Suramin Increased Telomerase Activity in the C6 Glioma/ Wistar Experimental Brain Tumor Model
Mine Ergüven,Ayhan Bilir,Tuncay Altug,Fadime Aktar
International Journal of Biomedical Science , 2007,
Abstract: Glioblastoma multiforme (GBM) is the most treatment-resistant glioma variant. Significant roles for telomerase in etiology, recurrence and drug resistance of GBM have been highlighted. Suramin (Bayer, Leverkusen, Germany) is an antineoplastic agent that affects many cellular mechanisms including growth factor, purinergic receptor, cytokine and key cellular enzymes signaling. The aim of this study was to investigate whether suramin, 40 mg/kg, i.p., inhibits telomerase activity in a subcutaneous C6 glioma/Wistar experimental brain tumor model using PCR based telomeric repeat amplification assay. In comparison to the control group, suramin increased tumor volume and telomerase activity. We also used transmission electron microscopy to evaluate the alterations of cell morphology. Apoptosis was seen markedly in electron micrographs of the control group and anti-apoptotic activity of telomerase was verified in the electron micrographs of suramin-applied group. The in vitro inhibitory effects of suramin on telomerase activity in several cell lines --except for brain tumors-- have been reported. Contrary to in vitro reports, our results were the first to demonstrate that suramin increased telomerase activity in a C6 glioma/Wistar experimental brain tumor. Large numbers of drugs exhibited apparent hormetic effects on cultured cancer cells and in vivo cancer growth. Several drug examples for their hormetic effects in vivo were listed as resveratrol, suramin, and tamoxifen. The action of suramin in the present study could be evaluated as one of the hormetic examples of suramin in vivo.
Emotions of Gynecologic Cancer Patients Dealing with Permanent Colostomy: A Qualitative Interview Study  [PDF]
Gül P?nar, Ali Ayhan, Tevfik P?nar
Journal of Cancer Therapy (JCT) , 2013, DOI: 10.4236/jct.2013.46120

Purpose: This study was conducted to describe emotional state of colostomized patients with gynecologic cancer. Patients and Methods: The study employed a qualitative design from May to October of 2010, in a private university hospitals outpatient gnecologic oncology clinic in Ankara, Turkey. Content analysis with an inductive approach had been used to analyze 32 interviews that served as the data base for this study. Interview form that focused on what gynecologic cancer women felt to living with a colostomy. Results: Findings also reveal that gynecologic cancer patients with colostomy experience many uneasy feelings that affect their emotional state. The content analysis resulted in the development of two thematic units. The first we described as “To experience the consequences of stoma as a gynecologic cancer patients”. The second was “suffering experienced-being challenged the consequences of the stoma”, and the third was “promote self management-normalization of the new condition”. For the psychological support, family and friends’ support has been mentioned as the most important part that can release their anxiety. Conclusions: We concluded that a having stoma was difficult for the women. The emotional state of the women when they get colostomy was typically characterized by fear, and worry about their current process. Body image, self-esteem, social activity, sexuality were the aspects that most affected the patients. Nurses have very important role within holistic approach and empathetic interaction, for determining major problem areas.

Simultaneous Intravitreal Ranibizumab and Dexamethasone Implant Administration at the Same Setting in Eyes with Severe Diabetic Macular Edema  [PDF]
Ali Osman Saatci, Ziya Ayhan, Ceren Durmaz Engin
Open Journal of Ophthalmology (OJOph) , 2016, DOI: 10.4236/ojoph.2016.62016
Abstract: Aim: To share our experience in eyes with severe DME (exhibiting serous retinal detachment or large cysts) treated with simultaneous intravitreal ranibizumab and dexamethasone implant administration at the same setting as the first treatment step. Subjects and Results: Five eyes of three patients with DME who were either treatment naive or relatively undertreated were presented in this report. As optical coherence tomography exhibited serous retinal detachment or severe cystoid edema with large cysts, intravitreal ranibizumab and dexamethasone implant were simultaneously employed at the same setting as the first treatment step in those eyes. Panretinal photocoagulation was also commenced bilaterally a week after the start of injections when at least one eye had retinal neovascularization. Subsequent treatments of intravitreal ranibizumab and/or dexamethasone implant were administered. Patients were followed up for seven, eight and 13 months respectively. All five eyes achieved a relative anatomic stability and experienced visual improvement at the end of follow-up. Conclusion: In some cases with severe DME with or without proliferative diabetic retinopathy, simultaneous intravitreal ranibizumab and dexamethasone implant administration at the same setting may be a better option to initiate the treatment over mono ranibizumab treatment. A randomized study comparing the mono anti-VEGF therapy and mono dexamethasone implant administration with simultaneous treatment may outline the place of this type of therapy in the treatment armamentarium of severe DME.
Lymphatic mapping and sentinel node biopsy in gynecological cancers: a critical review of the literature
Ali Ayhan, Husnu Celik, Polat Dursun
World Journal of Surgical Oncology , 2008, DOI: 10.1186/1477-7819-6-53
Abstract: Sentinel lymph node is the first node where primary tumor lymphatic flow drains first, and therefore the first node where cancer cells metastasize. Lymphatic metastasis has always been a focus of interest for the surgeons, as it is one of the first and foremost routes of spreading in many tumors and, because it shows the level of spreading. The condition of the lymph notes has vital importance in the planning and management of the treatments of many cancers.Lymphatic mapping is the passage of a marking dye or radioactive substance, injected by a tumoral or peritumoral injection, through the lymphatic vessels draining the primary tumor, that is, afferent lymphatic vessels, to the sentinel lymph node. This lymph node is the one with the highest possibility of involvement in case of metastasis from the primary tumor. According to lymphatic mapping hypothesis, if the sentinel node is negative in terms of metastasis, then non-sentinel nodes are also expected to be negative in that regard. However, there may be metastasis in the non-sentinel nodes even when the sentinel node is negative in terms of metastasis, due to reasons both explicable and inexplicable. Therefore there are reports of false negativity in literature studies [1].Sentinel lymph node biopsy concept was first developed to identify lymphatic metastasis in parotid carcinoma [2]. Later on, it has been used in penile carcinoma, breast, melanoma, lung, gastrointestinal, endocrine and gynecological cancers. Results of the studies about and experiences in gynecological cancers, particularly vulva cancer, and cervix cancer, as well as endometrial cancer, but to a lesser degree, have been published in the literature. The present study focused on the literature data about the results of the use of sentinel lymph node biopsy concept in gynecological cancers.Several techniques have been reported to identify the sentinel nodes. These are blue dye labeling, radiolabeling and combined labeling that comprise sequential ap
L5 vertebrectomy for the surgical treatment of tumoral and traumatic lesions of L5 vertebra
Tuncay Kaner,Tunc Oktenoglu,Mehdi Sasani,Ali Fahir Ozer
Orthopedic Reviews , 2012, DOI: 10.4081/or.2012.e10
Abstract: We retrospectively reviewed the clinical characteristics and the surgical results of seven patients treated with L5 vertebrectomy. The pathologies, clinical characteristics, preoperative and postoperative radiological findings, surgical techniques, and instrumentation for seven patients operated on between 1998 and 2009 are presented in this article. Biopsies were performed on all patients except those involving trauma. Patients were followed up at three-month intervals in the first year, at 6- month intervals in the second year, and on a regular basis afterward. One patient had a traumatic L5 burst fracture; the other six had tumoral pathologies in the L5 vertebrae. One tumoral lesion was a chordoma, another was a hemangioma, and the remaining four were metastatic lesions. Radiotherapy and chemotherapy were performed for the metastatic tumor patients during the postoperative period. Patients with renal cancer and chordoma survived for 3 years; patients with lung cancer and bladder cancer survived for 1 year; and patients with breast cancer survived for 16 months. The lumbosacral region presents significant stabilization problems because of the presence of sacral slope. In our opinion, if the lesion involves only the L5 vertebra, anterior cage-filled bone cement or bone graft should be performed, as dictated by the pathology and posterior transpedicular instrumentation. If the lesion involves the L4 vertebra or the sacrum and the L5 vertebra, the instrumentation can be extended to cover other segments with sacral attachments. The present cases involved only L5 vertebra and treatment with short-segment stabilization covering the anterior and posterior columns.
Unusual cause of acute low-back pain: sudden annulus fibrosus rupture
Ali Fahir Ozer,Tunc Oktenoglu,Mehdi Sasani,Tuncay Kaner
Orthopedic Reviews , 2012, DOI: 10.4081/or.2012.e22
Abstract: Low-back pain is a common problem in neurosurgery practice, and an algorithm has been developed for assessing these cases. However, one subgroup of these patients shares several clinical features and these individuals are not easy to categorize and diagnose. We present our observations for 8 of these patients, individuals with low-back pain caused by atypical annulus fibrosus rupture (AAR). The aim of this study is to show the consequences of overlooked annular tears on acute onset of low back pain. Eight patients with acute-onset severe low-back pain were admitted. Physical examinations were normal and each individual was examined neurologically and assessed with neuroradiologic studies [plain x-rays, magnetic resonance imaging (MRI), discography and computed tomography (CT) discography]. AAR was ultimately diagnosed with provocative discography. In all cases, MRI showed a healthy disc or mild degeneration, whereas discography and CT discography demonstrated disc disease. Anterior interbody cage implantation was performed in 3 of the 8 cases and posterior dynamic stabilization was carried out in 3 cases. The other 2 individuals refused surgery, and we were informed that one of them developed disc herniation at the affected level 1 year after our diagnosis. Clinical and radiological outcomes were evaluated. In cases where AAR is suspected, MRI, discography, and CT discography should be performed in addition to routine neuroradiologic studies.
New Silk Routes: Pipe Lines and Terminal Markets  [PDF]
Ayhan Orhan
Open Journal of Political Science (OJPS) , 2013, DOI: 10.4236/ojps.2013.31008

Energy will be the main determinant of the economic and political relations between the regions and nations during the years to come. The need for energy and the consumption of energy related to this need continues increasingly. The fossil fuels which meet the energy of many of the growing economies in the world, especially Chinabeing in the first place will continue to be the main energy source until the year2050. Intoday’s world, countries are classified as those which have rich reserves of natural resources and which obtain most of their revenues by selling these natural resources, those which have large amounts of consumption of natural resources and which import natural resources in spite of their own natural resources and as those which are dependant on outside resources but are on the route of transmission of natural resources because of their geopolitical positions. Turkey’s place is in the third group.Turkeyis the leading country among the countries which are situated on the route of the transmission of the natural resources.Turkeyis in a geographical region where its neighbors have rich natural resources, and this geographical region has approximately 70% of the fossil fuels which comprise a great deal of the energy needs in the whole world. Therefore, Turkey is at the center of the transmission corridor of the natural resources between the north and the south, and between the west and the east. TheUnited States of Americainstalled itself and settled down in the region at the beginning of the 90’s because of the first Gulf War, and theUnited Stateshas taken steps and some measures in order to support the establishment of new pipeline corridors for the transmission of natural resources. In the background of this support lies the thought and idea that by virtues of these pipelines the natural resources that exist in the Central Asian countries should be transmitted to the western world countries and to the international markets without any need for dependence onRussia. Another idea behind this is to put an end to the dominance of Russia over these countries.

Computational Multiaxial Fatigue Modelling for Notched Components*  [PDF]
Ayhan Ince
Modeling and Numerical Simulation of Material Science (MNSMS) , 2013, DOI: 10.4236/mnsms.2013.33A003
Abstract: Fatigue failures of driveline and suspension notched components for ground vehicles under multiaxial loading conditions are common, since most of those components are subjected to complex multiaxial loadings in service. A computational fatigue analysis methodology has been proposed here for performing multiaxial fatigue life prediction for notched components using analytical and numerical methods. The proposed multiaxial fatigue analysis methodology consists of an elastic-plastic stress/strain model and a multiaxial fatigue damage parameter. Results of the proposed multiaxial fatigue analysis methodology are compared to sets of experimental data published in the literature to verify the prediction capability of the elastic-plastic stress/strain model and the multiaxial fatigue damage parameter. Based on the comparison between calculated results and experimental data, it is found that the multiaxial elastic-plastic stress/strain model correlates well with experimental strain data for SAE 1070 steel notched shafts subjected to several non-proportional load paths. In addition, the proposed fatigue damage parameter is found to correlate reasonably well with experimental fatigue data of SAE 1045 steel notched shafts subjected to proportional and non-proportional loadings.
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