Development of a Digital Micromirror (DMDTM) based 3D profilmeter

Gelişen teknolojilere paralel olarak imal edilen ürünlerin boyutlarının küçülmesi ve yüzey hassasiyetlerinin artıp parçaların daha kırılgan yapıya sahip olmaları, araştırmacıları bilinen standart temaslı ölçme aletlerinin dışında hasarsız ve hızlı yeni ölçme tekniklerini aramaya yönlendirmiştir. Optik ölçme teknikleri de hasarsız ölçme kapasiteleri nedeniyle 1960’lardan başlayarak günümüze kadar büyük bir hızla gelişmiş ve günümüzde hiç tartışmasız mikro teknolojiden bio-teknolojiye birçok alanda temaslı ölçme cihazlarının yerini almıştır. Konfokal mikroskop ise 1960 yılında M. Minsky tarafından geliştirilmiş ve standart mikroskoplara oranla daha hassas ve detaylı ölçme kapasitesi sunması nedeniyle diğer optik ölçme metodları arasından hızla sıyrılmıştır. 1990’larda, Xiao, Corle, ve Kino’nun çalışmaları ile gerçek zamanlı görüntüleme özelliği kazandırılmış ve konfokal mikroskop endüstrinin vazgeçilmez temel optik ölçme cihazı haline gelmiştir. Bu çalışma kapsamında mikro ayna dizinli (DMD™) optik anahtarların yardımı ile yeni bir tip konfokal mikroskop geliştirilmiştir. Geliştirilen bu yeni ölçme sisteminde mikro ayna dizini ölçülecek yüzey üzerine 1-1 görüntülenmiş ve bu sayede yüzlerce noktanın aynı anda video frekansında ölçülmesi gerçekleştirilmiştir. 3D yüzeyin elde edilmesi çeşitli yüksekliklerde elde edilen 2D bilgilerinin üst üste getirilmesi ile oluşturulmuştur. Bu çalışma sırasında mikroskobun optik tasarımı ve elde edilen optik sistemin geliştirilme aşamaları bütün detayları ile verilmiş, geliştirilen deneysel düzenek detayları ile tartışılmıştır. Ölçümler sırasında 50 defa büyütmeli ve 0.95 NA’ya sahip mikroskop objektifi ile yapılan ölçümlerde yatay çözünürlük değeri 1.5 µm olarak bulunmuştur. Sonuçların bu kadar iyi olmasında kullanılan mikro ayna dizinli elemanın önemli bir rolü olmuştur. Geliştirilen sistemin ölçme kapasitesi farklı ölçme standartları kullanılarak örneklendirilmiştir.  Anahtar Kelimeler: DMD, optik ölçümler, konfokal mikroskop.In this paper a new method for non-contact scanning of engineering surfaces will be presented. Similar to the classical confocal microscope principal but without using real physical pinholes a new method that uses Digital Micromirror Device  (DMDTM) as virtual illumination pinhole and selective CCD camera as virtual detection is developed. With this study, this new, flexible and highly accurate a micromir-ror-based system will be introduced. The concept concerning system layout and system performance together with the measurement results will be presented.Confocal microscopy was first described by M. Minsky in 1957 and in last couple decades it becomes one of the most powerful tool for 3D characterization of complex engineering surfaces. In reflection mode confocal microscopy applications a point illumination source is imaged onto object by using a microscope objective (first focus point). This focusing point on object results with maximum intensity on a detector by passing through the detector pinhole (second focus point) where the lights from defocused neighborhoods object regions are strongly suppressed by the pinhole. In other words, the detector signal that is determined by the pinhole size is reduced strongly by defocusing the specimen. This characteristic of confocal system gives us a chance to make optical sectioning with high vertical resolution discrimination by suppressing the scattered light from defocused object position. It is also well known that confocal microscopy gives some improvements in the sense of lateral resolution compared to the classical microscopy. (DMDTM) technology was developed by Texas Instruments. The DMD that used in the setup consists of 600x800 programmable micromirrors. Each of these mirrors has 16 m x 16 m square size with a 1m gap between them and each mirror tilt 10 around the diagonal axis with help of underlying memory cel. DMD as a member of MEMS device can also be used as a light switch. By combining the DMD with a suitable light source and optics, the DMD reflects the incoming beam either into or out of the microscope objective pupil by using a simple beam steering technique. By combining the light switch advantages of DMD unit with pulse width modulation application it is also possible to create gray scale operation, which can be used to obtain uniform illumination on CCD. By controlling the DMD pixels as an optical light switch any size and any shape pinholes, which are imaged through the optical system onto object where they are reflected and later imaged again onto CCD camera chip, can be created. On the CCD camera reflected intensities from the object are measured by the CCD pixels that are related with DMD's "on" pixels. The measured intensities reach its maximum when the object is confocally in focus with the DMD and the CCD. Intensity data are measured and stored while the object is moving through the focal plane of the optical system. Finally maximum's of the obtained intensity curves, which are also known as depth response curves, link to the corresponding motor position and the 3D profile of the specimen can be reconstructed. The advantages of the DMD based optical scanner can be listed as follows; conventional scanning devices such as Nipkow disk or tilting mirrors that introduce vibration and mechanical noises to system are eliminated, important flexibilities are introduced by DMD application, critical parameters such as pinhole size and pinhole shape can easily be changed, local illumination, which supplies uniform illumination on detector, can be introduced. The main challenges are differences between the images produced by the real illumination pinhole and the DMD, respectively, is the contrast ratio. The ground level intensity of the DMD image is higher because of stray light from the mirror edges and the protective glass layer. At the same time, the maximum intensity is lower because of transmission loss through the glass and reflection loss of the mirror elements. However, although the contrast ratio is worse with a DMD, the depth response curves taken with a regular pinhole and with a DMD show perfect comparability. This new microscope offers unique flexibility for pinhole size and shape that existing system can not do. It is also showed that the measurement results of the developed system are comparable with the stylus instruments and DMD based optical systems are an alternative to tactile techniques. Keywords: DMD, optical measurement, confocal microscopy

Is there a relationship between fracture healing and mean platelet volume?

Sancar Serbest,1 Ugur Tiftikci,1 Haci Bayram Tosun,2 Seyit Ali Gumustas,2 Abuzer Uludag2 1Department of Orthopaedics and Traumatology, Faculty of Medicine, Kırıkkale University, Kırıkkale, 2Department of Orthopaedics and Traumatology, Faculty of Medicine, Adiyaman University, Adiyaman, Turkey Objectives: Platelet volume has been defined to be a marker that shows thrombocyte activation and function and it is measured as mean platelet volume (MPV). MPV shows the mean volume of circulating thrombocytes and it is one of the routine parameters in complete blood count. Increased thrombocyte volume is associated with thrombocyte activation. Patients and methods: This study included 76 patients who were operated on due to fractures of long tubular bones. Patients who had union without any additional interventions were defined as group I, and patients who needed additional interventions due to nonunion or inadequate union were defined as group II. The control group included healthy volunteers who did not have a fracture. Hematologic test values of the patients that were obtained at admission to emergency ward were recorded Results: The groups were not statistically different in terms of age, sex, and the affected extremity. There were significant differences between group I and group II in terms of mean erythrocyte sedimentation rate, C-reactive protein, and MPV values (P<0.001), but there were no significant differences between group I and the control group. There was also no statistically significant difference among groups in terms of hematologic and biochemical variables. Conclusion: In our study, fractures in patients who had lower MPV values than controls during the inflammation process healed without any problem, but fractures in patients with high MPV values more frequently needed additional surgical interventions. Keywords: fracture healing, bone tissue, mean platelet volume, platelet activation, inflammatio

The prevalence of the mutation in codon 249 of the P53 Gene in Patients with Hepatocellular Carcinoma (HCC) in Turkey

Hepatocellular carcinoma (HCC) is one of the most common cancers in the worldwide. Aflotoxins, products of Aspergillus Flavus found in the high humidity environments induce HCC in humans by causing mutations in oncogenes such as codon 249 mutation of p53 in hepatocytes. In turkey, aflatoxins are found to be increased in some foods in certain areas, such as Istanbul which have high humidity. In present study we aimed to look for the prevalence of codon 249 mutation of p53 in patients with HCC, cirrhosis and chronic hepatitis B (CHB). Methods DNA was extracted from plasma and mutation was detected by PCR-RFLP method. Results the codon 249 mutation of p53 is found one out of 50 HCC (2%) patients. In conclusion, although codon 249 mutation of p53 gene has been found very rare but it exists showing the effect of aflatoxins in HCC patients in Turkey. © Springer Science+Business Media, LLC 2010.National Council for Scientific Research: SBAG-HD-57, 105S301This study was supported by The Scientific and Technical Research Council grant SBAG-HD-57 (105S301). F.T.Özdemir(*).F.Eren.V.Tahan.H.Akın.F.Gündüz. A. E. Kedrah.E. Avşar.O. Özdoğan Institute of Gastroenterology, Marmara University, Istanbul, Turkey e-mail: [email protected]