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Lazerler gelişiminden bu yana günlük hayatımızı kolaylaştırarak günümüz teknolojisindeki ilerlemede büyük bir etkiye sahip olmuştur. İmalat sanayi lazer teknolojisinden en büyük payı almış ve birçok imalat uygulamasında tercih edilen bir teknoloji haline gelmiştir. Lazerle neredeyse bütün malzeme türüne işlem yapılabilmekte ve lazer teknolojisi endüstride markalama, kazıma ve kesme işlemlerinde yaygın olarak kullanılmaktadır. Bu çalışma markalama, kazıma ve kesme uygulamaları için düşük bütçeli bir CO2 lazer makinesinin tasarlanmasını ve üretilmesini ele almıştır. Makinenin rezonatör, optik hareket, kesim kafası ve kontrol sistemleri dahil olmak üzere tüm ana bileşenleri, ilgili okuyucuların benzer bir sistemi uygulaması için etraflıca açıklanmıştır. Makinede bulunan rezonatör, ticari olarak mevcut benzer sistemlere kıyasla ekonomik ve uzun servis ömrüne büyük bir fayda sağlayan tekrarlı gaz dolumuna izin verecek şekilde tasarlanmış ve üretilmiştir. Üretilen makine, ilk malzeme listesinden ve ilgili üretim sürecinden kauçuk, ahşap ve plastik malzemeler için yukarıda bahsedilen son uygulama örneklerine kadar açıklanmıştır. Lazer makine sistemi şu anda Karabük Üniversitesi imalat mühendisliği bölümünde kuruludur ve lisans eğitimi ve öğretimi için kullanılmaktadır. Ayrıca makine reklam, hobi, orman ürünleri, tekstil, deri ve küçük ölçekli mühendislik işlerinde orta ölçekli işletmelerin kullanımı için yeterli kapasiteye sahiptir., Since its early development, lasers had big impact in today’s technology advancement by facilitating our daily life. The manufacturing industry has taken the largest share of laser technology, and it has become a preferred technology in many manufacturing applications. Almost all material types can be processed with the laser and laser technology is widely used in industry for marking, engraving, and cutting processes. This article discusses designing and manufacturing of a low-budget CO2 laser machine, for marking, engraving, and cutting applications. All major components of the machine including resonator, optical train, cutting head and control systems have been discussed in detail for interested readers to implement a similar system. The resonator on the machine was designed and manufactured to allow repeated gas filling which is a major benefit for economical and extended service life as compared to similar commercially available systems. The machine has been described from initial material list and manufacturing process involved, all the way to the final aforementioned application examples for rubber, wood, and plastic materials. The laser machine system is currently installed in Karabuk Univesity’s manufacturing engineering department and used for undergraduate teaching and learning. Furthermore, it is sufficient capacity for use in medium-sized operations in advertising, hobby, forest products, textile, leather, and small-scale engineering works.

Stroke is a leading cause of death worldwide. Possible treatments that can be administered in the sub-acute phase and stimulate restorative mechanisms by enhancing vascular remodeling are clinically not available. Amitriptyline has been used for treatment of anxiety and depressive disorders for decades. In recent years, amitriptyline and other antidepressants have been demonstrated to functionally inhibit the activity of acid sphingomyelinase (human protein: ASM; murine protein: Asm) which catalyzes the production of the bioactive sphingolipid ceramide. Promising pre-clinical and clinical studies demonstrated that ASM inhibitors induce neuroprotection and ameliorate behavioral outcome after stroke. The underlying mechanism has not been identified. Herein, we studied the effect of amitriptyline on brain remodeling in a model of transient intraluminal middle cerebral artery occlusion (tMCAO). By means of high-resolution light sheet fluorescence microscopy, we provide evidence that amitriptyline promotes angiogenesis in an Asm/ ceramide-dependent way in previously ischemic, reperfused brain tissue. In cerebral microvascular endothelial cells exposed to ischemia/ reperfusion injury, mimicked by oxygen-glucose deprivation (OGD) and subsequent reoxygenation/ glucose recultivation, ceramide accumulated in intracellular vesicles that were characterized as multivesicular bodies/ late endosomes. These vesicles were released from the cells in response to amitriptyline. Extracellular vesicles (EVs) derived from amitriptyline-treated cells induced angiogenesis and mimicked the effect of direct amitriptyline administration in vitro. In vivo, the promotion of angiogenesis by amitriptyline was ensued by a robust surrogate of successful brain tissue remodeling, that is, increased blood-brain barrier integrity, reduced inflammation and enhanced neuronal survival. These data provide a rationale for the use of ASM inhibitors in the treatment of ischemic stroke. Dissertation, Universität Duisburg-Essen, 2020

Grade AH36 ship steel plate, frequently used in offshore applications, was joined underwater by shielded metal arc welding (SMAW) using two different types of electrodes (E6013 and E7014). The ship steel plate was also joined under atmospheric conditions in order to compare both joints in terms of mechanical and metallurgical properties. The E6013 rutile electrode was isolated by wrapping before use, and the underwater welding process was carried out at a depth of 8 m under the sea. The joints were first subjected to visual inspection and then liquid penetrant, ultrasonic, and radiographic tests were performed. In order to determine the mechanical properties of the joints, tensile, bending, and impact toughness tests were also carried out. In addition to the microhardness test on the weld zones, microstructural examination was also performed on the joints. As a result of the nondestructive tests, weld defects like slag remaining between the passes, gas porosities, burn-through, and lack of penetration were seen on the joints welded underwater with the two different electrodes. The study determined that these defects had significantly influenced the mechanical properties and width of the weld zone of the joints.

WOS: 000514814600011, The use of aluminum alloys in industry have been increased in due to their excellent low weight, corrosion resistance also other good features. Different aluminum alloys are joined with together when need of a structure presents different physical or mechanical properties with together. in this study, different aluminum alloys AA5754 and AA6013 joined by GMAW (gas metal arc welding) method under different welding parameters. After that, three-point bending test was carried out and notch impact test was performed to determine toughness behavior of the joints. in addition, the weld zone is characterized with hardness test and microstructure studies. While the welded samples joined with convenient parameters were bended 180 degrees, the cracks and fractures were occurred on the fusion line boundary of some samples due to unsuitable parameters. According to impact toughness test results, the highest toughness value was obtained from the HAZ (Heat affected zone) of AA5754. Besides, toughness values evaluated from the HAZ of AA6013 on the joints and weld metal were nearly same. With respect to hardness test results, the maximum hardness value was measured at the HAZ of AA6013 and this was followed by the weld metal and the HAZ of AA5754 sequentially. From the point of microstructure inspections, structures of all the weld metals were dendritic.

Until recently, the visualization of cerebral microvessels was hampered by the fact that only short segments of vessels could be evaluated in brain sections by histochemistry. These limitations have been overcome by light sheet microscopy, which allows the 3D analysis of microvasculature in cleared brains. A major limitation of light sheet microscopy is that antibodies do not sufficiently penetrate cleared brains. We herein describe a technique of reverse clearing and rehydration, which after microvascular network analysis allows brain sectioning and immunohistochemistry employing a broad set of antibodies. Performing light sheet microscopy on brains of mice exposed to intraluminal middle cerebral artery occlusion (MCAO), we show that in the early phase of microvascular remodeling branching point density was markedly reduced, more strongly than microvascular length. Brain infarcts in light sheet microscopy were sharply demarcated by their autofluorescence signal, closely corresponding to brain infarcts revealed by Nissl staining. Neuronal survival, leukocyte infiltration, and astrocytic reactivity could be evaluated by immunohistochemistry in rehydrated brains, as shown in direct comparisons with non-cleared brains. Immunohistochemistry revealed microthrombi in ischemic microvessels that were likely responsible for the marked branching point loss. The balance between microvascular thrombosis and remodeling warrants further studies at later time-points after stroke. OA Förderung 2021

Inflammatory diseases of the gastrointestinal tract are emerging as a global problem with increased evidence and prevalence in numerous countries. A dysregulated sphingolipid metabolism occurs in patients with ulcerative colitis and is discussed to contribute to its pathogenesis. In the present study, we determined the impact of acid sphingomyelinase (Asm), which catalyzes the hydrolysis of sphingomyelin to ceramide, on the course of Citrobacter (C.) rodentium-driven colitis. C. rodentium is an enteric pathogen and induces colonic inflammation very similar to the pathology in patients with ulcerative colitis. We found that mice with Asm deficiency or Asm inhibition were strongly susceptible to C. rodentium infection. These mice showed increased levels of C. rodentium in the feces and were prone to bacterial spreading to the systemic organs. In addition, mice lacking Asm activity showed an uncontrolled inflammatory Th1 and Th17 response, which was accompanied by a stronger colonic pathology compared to infected wild type mice. These findings identified Asm as an essential regulator of mucosal immunity to the enteric pathogen C. rodentium. OA Förderung 2019

In this study the repair-maintenance welding process performed with MAG welding method by a MIG-MAG welding equipment mounted on the 3D printing machine. For this aim an assumed broken machine gear was used. The CAD model of the broken gear designed and cut by laser cutting machine. Then the broken gear fixed exactly on the 3D metal printer. There is an important difference between accumulation of metals and accumulation of plastic materials. Operating temperature of plastics are between 190-200°C although metals are about between 3000-4000°C. Thus, it is inevitable that high operating temperatures effect adversely working of the 3D metal printer used in this study. For this reason, to deposite metal materials, important revisions applied on the 3D metal printer. Depositing process of the broken gear areas carried out four passes by MAG welding equipment (two are bottom side and other two are top side of the part)., Buçalışmada; MIG-MAG kaynak ünitesi, 3B metal yazıcıya monte edilerek MAG kaynakyöntemi ile bir tamir-onarım kaynak işlemi gerçekleştirilmiştir. Bu amaç içinkırılmış kabul edilen bir makine dişlisi kullanılmıştır. Kırılmış dişlinintasarımı bilgisayar destekli ortamda tasarlanıp lazer kesme işlemi ileüretilmiştir. Daha sonra kırık olan dişli parçaları hassas bir şekilde 3B metalyazıcının tablasına sabitlenmiştir. 3B yazıcıyla metal malzeme ve plastikmalzeme biriktirme işlemleri arasında önemli bir fark bulunmaktadır. 3Byazıcılarda plastik malzeme kullanıldığında çalışma sıcaklığı yaklaşık 190-200°C arasında iken metal malzeme ergitilirken çalışma sıcaklığı yaklaşık3000-4000 °C’ye ulaşır. Bu çalışma sıcaklığının çok yüksek olması 3 boyutlumetal yazıcının çalışmasını olumsuz yönde etkilemektedir. Bu nedenle çalışmadametal doldurma işlemini gerçekleştirmek için 3 boyutlu metal yazıcıda önemliuyarlamalar yapılmıştır. Kırık dişli parçalarının tamir edilecek bölgesinidoldurma işlemi MAG kaynağı ile ilk ikisi parçanın üst tarafından diğer ikisiise alt tarafından olacak şekilde dört pasoda gerçekleştirilmiştir