Experimental intervertebral disc degeneration models

Intervertebral disc degeneration is a major health problem of close concern to both young and old. The problem is also growing as the global population ages. Intervertebral disc degeneration is defined as progressive changes affecting the spine as a component of natural aging under the effect of multiple factors (such as smoking, obesity, and incorrect exercise). For a solution to be found, experimental disc degeneration must first be induced, the causes of the disease must be identified, and early diagnostic and therapeutic methods must then be developed. Methods of inducing intervertebral disc degeneration with high applicability in rats were identified from the previous literature. This review discusses four methods of disc degeneration induction. It also discusses how to detect degeneration formation and development times. As a result of the literature review, information about four different and reliable intervertebral disc degeneration methods is presented

Introducing a new risk factor for Lumbar Disc Herniation in females : vertical angle of the sacral curvature

Kanat, Ayhan/0000-0002-8189-2877WOS: 000313134700003PubMed: 23323164Objective : To characterize the importance of the vertical angle of the sacral curvature (VASC) in lumbar disc herniations. Methods : Morphological data derived from lumbar sagittal MRI imaging. the statistical significance of the findings are discussed. the angles of 60 female patients with lumbar disc herniations (LDH) were compared with the 34 female patients without LDH. Results : 128 of the 185 patients met our inclusion criteria. the vertical angle of sacral curvature is statistically significantly bigger in females with lumbar disc herniations when compared to subjects in control group, 28.32 and 25.4, respectively. (p=0.034<0.05). Same difference was not seen in males. Conclusion : the vertical angle of sagittal sacral curvature may be another risk factor in females with lumbar disc herniations

THE EFFECT OF CHRONIC KIDNEY DISEASE IN PATIENTS WITH SPONTANEOUS SPONDYLODISCITIS

Objective: Spontaneous spondylodiscitis is a rare but serious infectious disease of the vertebral column that can lead to permanent neurological deficits. We investigated the differences during follow-up of this pathology, which is more common in patients undergoing hemodialysis (HD) treatment for chronic kidney disease (CKD), compared with the general population. Materials and Methods: The data of patients who were treated for spontaneous spondylodiscitis between 2016-2021 at the Başkent University Department of Neurosurgery were used retrospectively. The patients were divided into 2 groups according to the diagnosis of CKD. Demographic data of the patients, biochemical values at the time of diagnosis (C-reactive protein, sedimentation, leukocyte, lymphocyte), microbiological and pathological examination results, and treatment method (surgical, medical) applied after diagnosis was obtained from the medical records. The effects of CKD presence and treatment methods on patient survival were investigated. Results: Of the 49 patients included in the study, 57.1% were female and the mean age was 66 years. Twenty-four of the patients were chronic HD patients. The microbiological examination of the samples taken determined that the causative pathogen could be produced in the cultures of 21 (42.8%) patients. According to the results of the pathological examination, signs of infection were detected in 24 (48.9%) patients. It was determined that 27 of the patients were operated. There was a central venous catheter in 20 of the patients. There was no statistically significant difference in survival between the groups that were operated on for instability and those that were not operated on. However, chronic renal failure and the presence of central venous catheters increased mortality statistically significantly. Conclusion: In the presence of back pain in chronic HD patients, spondylodiscitis should be suspected and diagnosed at an early stage, even if there is no fever or high infection parameters. Finally, great emphasis on disinfection procedures and aseptic techniques in patients with central venous catheters protected from these serious infectious complications

Combınıng Age Hardenable Alumınıum Alloys Wıth Frıctıon Stır Weldıng And Examınıng Mechanıcal Propertıes After Weldıng

Sürtünme Karıştırma Kaynak (SKK) yöntemi gelişen kaynak yöntemlerinden biridir. Bu kaynak yönteminde birleştirilecek olan malzemeler sürtünme ısısı oluşturan bir takım ile ergime noktası altında bir sıcaklığa çıkartılır. SKK yönteminde kullanılan takım sadece ısı oluşturmaz bunun yanında birleştirilecek malzemeleri birbiri içinde karıştırarak birleştirme işlemi yapar. Bu çalışmada, gösterdiği yüksek mekanik özelliklerle öne çıkan Alüminyum Alaşımlarından Al-7075 malzemelerde sertlik ve mukavemet artışı sağlayan ısıl işlem süreçlerinden olan yaşlandırma sürecinin, SKK yöntemi öncesi ve sonrasında numunelere uygulanarak metodun birleşme kalitesine etkisi araştırılmıştır. Sonlandırma uygulamalarından olan ve yüzey pürüzlülüğü ve yüzey sertliğini geliştiren haddeleme operasyonu da yapılan kaynak işlemleri sonrasında kullanılmıştır. Kaynak yapılan parçalara yaşlandırma ve kaynak bölgelerine haddeleme işlemleri farklı kombinasyonlarla uygulanarak en uygun ve etkili kaynak şartları araştırılmıştır. Kaynak işlemleri sonrasında malzemelerin içyapı incelemeleri ile çekme ve eğme testleri gerçekleştirilmiştir. Bu çalışmada SKK ile birleştirilmiş parçalar üzerinde uygulanan işlemlerden haddeleme ve yaşlandırma işlemlerinin malzeme mekanik özelliklerine olumlu katkı sunduğu görülmüştür. Birleştirilen parçalarda haddeleme ve yaşlandırma işlemleri çekme ve eğilme mukavemetini artırmıştır. Yaşlandırma işlemi birleştirilen malzemelerin mikrosertlik değerlerini iyileştirmiştir. Yaşlandırma işleminin kaynak bölgeleri arası farkların giderilmesinde de tercih edilebilir bir yöntem olduğu görülmüştür. Haddeleme işlemi ise malzemenin üst yüzeyinden 0,2~0,3 mm derinliğe kadar mikrosertlik değerlerine olumlu etki sağlamıştır. Bununla birlikte haddeleme ve yaşlandırma işlemlerinin birlikte uygulandığı örneklerde mekanik özelliklerin olumsuz yönde etkilendiği tespit edilmiştir.Friction Stir Welding (FSW) is one of the developed welding methods. In this welding method, frictional heat that creates the materials to be joined with a tool heated to a temperature below the melting point. FSW tool not only creates heat but also makes the mixing process to merging workpieces together. In this study, the effect of the aging process, which comes to the forefront with high mechanical characteristics and which increases the hardness levels and the strength in Al-7075 materials, has been investigated by applying it before and after the FSW Method. Burnishing operation, one of the finishing operation effects of improving the surface roughness and surface hardness after the welding has also been used. The welded parts received aging and burnishing operations in different combinations to investigate the most proper and efficient welding condition. The analysis of the microstructure of the materials after the welding process, micro hardness measurement, microscope analysis, tensile and bending tests have been performed. In this study, it was observed that burnishing of the joined parts and the aging process increased tensile and bending strength. The aging process has improved the micro hardness values of the combined materials. To eliminate the difference between the welding regions of the aging treatment was also found to be a preferable method. The burnishing process in the material to a depth of 0.2 to 0.3 mm from the upper surface of the micro hardness values has provided a positive impact. However, a combination of the burnishing and the aging process applied on samples has been determined to be adversely affected

INVESTIGATION OF THE BURNISHING PROCESS EFFECT OF THE ON SURFACE ROUGHNESS AND SURFACE HARDNESS

Haddeleme işlemi talaşlı imalatta son işlem operasyonu olarak kullanılmakta ve uygulandığı iş parçası yüzeylerinde sertliğin artması, malzeme yorulmasına karşı dayanıklılık ve aşınma direnci gibi avantajları da beraberinde getirmektedir. Haddeleme işleminde kullanılan , ilerleme, haddeleme kuvveti, kullanılan silindir sayısı, bilye yarıçapı gibi parametreler iş parçasının yüzey pürüzlülüğünün iyileştirilmesi, yüzey sertliğindeki iyileşmeler, malzemenin aşınma direncinin artması, malzeme yüzeyinde çatlak oluşturabilecek derinliklerin azaltılması vb., direk olarak etkiler. Bu çalışma ile dönel parçalar için haddeleme işlemi yapabilecek farklı başlıklar takılabilen bir aparat tasarlanma amacı güdülmüştür. Tasarlanan aparatın imalatı gerçekleştirilerek aparat ile talaşlı imalat işlemi yapılmış olan yüzeyler farklı parametreler kullanılarak haddeleme işlemine tabi tutulmuş ve parça için yüzey pürüzlülüğü ve sertliği sonuçları elde edilmiştir. Deneysel sonuçlar ölçüm cihazı ile elde edilmiştir. Elde edilen bu sonuçlar YSA (Yapay Sinir Ağları) ile yorumlanmış ve bu yorumlar deneysel sonuçlarla karşılaştırılmıştır.Burnishing process has been used as a finishing operation in manufacturing and applied on work piece surface brings together some advantage like that increase hardness, resistance against material fatigue and abrasion resistance. In burnishing process is used some parameters Like that Feed, burnishing force and pass number parameters and this parameters effect to improving work piece surface roughness, refining surface hardness, increasing material abrasion resistance, decreasing depth created cracked on material surfaces.With this study, it has been aimed an apparatus design with capable to mount different heads make burnishing process for cylindrical parts. Realization of manufacturing designed apparatus and on work piece surface which is processed chip removal method, material improving (surface roughness, hardness,) experiment will be done with this apparatus usnig different parameters to obtain result contains surface roughness and surface hardness. Experimental result taken with using necessary measurement device. Obtained result interpreted with ANN (artificial neural network) and comparison with experimental result. Science Code : 708.3.029 Key Words : Burnishing,ANN,Finishing operation

Do okolja prijazen pristop k obdelavi težje odrezovalnega dupleksnega nerjavnega jekla AISI 4462 z vrtinčno cevjo

Machining is a manufacturing process that can be used to produce precision machine parts and has many advantages. The first is the ability to achieve superior surface quality. Tool wear is an inevitable phenomenon that occurs during machining. It is affected by many machining conditionstherefore, this process needs to be monitored and controlled. In this study, tool wear and surface roughness tests were carried out on AISI 4462 duplex stainless-steel materials, known to be a hard-to-cut material. For this purpose, tool wear and surface roughness analyses were implemented by using the environmentally friendly vortex tube cooling system in addition to wet turning conditions for the first time. For both methods, experiments were conducted at a 1 mm depth of cut, 120 m/min cutting speed, and 0.1 mm/rev feed with a 90 mm cutting length for each pass. Both tool wear and surface roughness were examined at the end of each pass. The analysis showed that wet turning gave better results in terms of tool life (19.8 minutes of tool life) compared to 11.1 minutes of tool life in vortex turning. In contrast, the surface roughness values differed up to two times in some experiments, and the vortex tube experiments gave better surface roughness values in all passes. In addition, the vortex tube experiments showed less built-up-edge (BUE) formation than the wet-turning experiments