37 research outputs found

    The importance of carotid artery stiffness and increased intimamedia thickness in obese children

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    Background. Atherosclerosis that starts in childhood invariablyadvances during adulthood.Aim. We aimed to study the effect of obesity on main carotidartery intima-media thickness (CIMT) and arterial stiffness.Material and methods. A total of 78 children were studied fromOctober 2010 to February 2011. They were divided into obese (n=42,group 1) and normal (n=36, group 2). All children were subjectedto physical examination, routine biochemical and haematologicalanalysis, carotid ultrasonography and echocardiographicmeasurements. A detailed medical history was obtained. Bodymass index (BMI) was calculated by dividing participants’ weight inkilograms by the square of their height in metres. Stiffness index âwas calculated using blood pressure and diameter of the systolicand diastolic artery. Intima-media thickness was also measured.Results. The mean age of the obese and normal (control) groupswas 10.12±2.12 years and 9.78±1.78 years, respectively. Weight, BMI,and systolic and diastolic blood pressure values were significantlyhigher in the obese group (all p<0.001). In terms of arterial stiffnessand CIMT measurements, all parameters were higher in the obesegroup than the control (p<0.001). There was a relationship betweenthe degree of obesity and CIMT or stiffness index â. In addition,dilatation and hypertrophy levels in the left ventricle were higherin obese children.Conclusions. Obese children with risk factors for multipleatherosclerosis could have increased CIMT dimensions and,consequently, should be screened for these risks. UltrasonographicCIMT and arterial stiffness measurements can detect vasculardamage at an early stage of development in children withcardiovascular risk factors

    Design of a Gd-DOTA-Phthalocyanine Conjugate Combining MRI Contrast Imaging and Photosensitization Properties as a Potential Molecular Theranostic

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    Cataloged from PDF version of article.The design and synthesis of a phthalocyanine - Gd-DOTA conjugate is presented to open the way to novel molecular theranostics, combining the properties of MRI contrast imaging with photodynamic therapy. The rational design of the conjugate integrates isomeric purity of the phthalocyanine core substitution, suitable biocompatibility with the use of polyoxo water-solubilizing substituents, and a convergent synthetic strategy ended by the use of click chemistry to graft the Gd-DOTA moiety to the phthalocyanine. Photophysical and photochemical properties, contrast imaging experiments and preliminary in vitro investigations proved that such a combination is relevant and lead to a new type of potential theranostic agent

    Data digitization techniques used in the analysis of free oscillation of human lower limb

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    In biomechanics, the ability to manipulate the video data of the desired human motion using computer vision is as important as obtaining the numerical solutions from mathematical modeling. This paper covers both of these requirements equally. The proposed model presents the concept of data digitizing of recorded video films of free in vivo oscillation of human lower limb. The analysis is carried out using an interactive Graphical User Interface (GUI) object oriented analyzing software

    High mobility and low operation voltage organic field effect transistors by using polymer-gel dielectric and molecular doping

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    In this work, we present a method to increase the performance in solution processed organic field effect transistors (OFET) by using gel as dielectric and molecular doping to the active organic semiconductor. In order to compare the performance improvement, Poly (methylmethacrylate) (PMMA) and Poly (3-hexylthiophene-2,5-diyl) P3HT material system were used as a reference. Propylene carbonate (PC) is introduced into PMMA to form the gel for using as gate dielectric. The mobility increases from 5.72×10?3 to 0.26 cm2 V s–1 and operation voltage decreases from ?60 to ?0.8 with gel dielectric. Then, the molecular dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) is introduced into P3HT via co-solution. The mobility increases up to 1.1 cm2 V s–1 and the threshold voltage downs to ?0.09 V with doping. The increase in performance is discussed in terms of better charge inducing by high dielectric properties of gel and trap filling due to the increased carrier density in active semiconductor by molecular doping. © 201

    ATA50 telescope: Hardware

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    3rd Workshop on Robotic Autonomous Observatories --7 October 2013 through 11 October 2013 -- --ATA50 Telescope is a new telescope with RC optics and 50 cm diameter. It was supported by Atatürk University Scientific Research Project (2010) and established at about 2000 meters altitude in city of Erzurum in Turkey last year. The observations were started a few months ago under the direction and control of Atatürk University Astrophysics Research and Application Center (ATASAM). The technical properties and infrastructures of ATA50 Telescope are presented and we have been working on the robotic automation of the telescope as hardware and software in order to be a ready-on-demand candidate for both national and international telescope networks

    Performance improvement in photosensitive organic field effect transistor by using multi-layer structure

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    In this study, a new approach was introduced for Photo-OFETs as a multi-layer structure. Poly(3-hexylthiophene-2,5-diyl) regioregular (P3HT) and Copper(II) phthalocyanine (CuPc) thin films were used as two different active photo-absorber layers in the same device structure. Poly(methyl methacrylate) (PMMA) was used as a dielectric layer and all devices were fabricated with a top-gate bottom-contact configuration. In order to investigate the effect of the location of each layer on the Photoresponsive organic field-effect transistors (Photo-OFET) performance, five different devices in various structures were produced and analyzed. Surface properties of active layers have been investigated via Atomic Force Microscopy (AFM) and effects of surface roughness on device performance have been discussed. P3HT/CuPc/P3HT multi-layered structure exhibited the best performance in terms of photoresposivity(as 45 mA/W) and photosensitivity (~ 2 × 10 3 ). Photo-OFET based on a multi-layer structure demonstrated superior performance with wider absorbance spectrum region compared to conventional single component devices of P3HT or CuPc. The proposed multi-layer structure can be a model to improve the realization of high performance Photo-OFETs. © 2019 Elsevier B.V

    A VOC sensor based on micromechanical cantilever functionalized with ZNO nanorods

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    Agilent;Centre for Biological Signalling Studies (BIOSS);Forum for Applied Informatics and Microengineering (FAIM);HSG-IMIT;MicroTec Sudwest;Roche Diagnostics17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013 -- 27 October 2013 through 31 October 2013 -- Freiburg -- 107378This study reports a novel method for volatile organic compound (VOC) detection with a functionalized microcantilever-based sensor. The devices are fabricated with lithography and electrodeposition processes. ZnO nanorods are deposited on Ni microcantilevers in order to expand the total sensitive area. The VOC sensor measurements are carried out with magnetic actuation and optical read out. The phase stability and limit of detection for diethylamine (DEA) were 0.02° and below 100 ppm, respectively. ZnO nanorod coated microcantilevers have potential for VOC sensor especially for amine groups due to the high surface area-to-volume ratio

    Fabrication of 1D ZnO nanostructures on MEMS cantilever for VOC sensor application

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    This study reports the fabrication method and sensing performance for novel 1D zinc oxide (ZnO) nanorods and nanotubes grown on nickel MEMS cantilevers. The fabrication of the nanostructures and the cantilevers are simple and low-cost using standard lithography, electrodeposition, and hydrothermal etching processes. 1D ZnO nanostructures increase the total sensitive area for biological and chemical sensor applications. We performed experiments with various VOCs with a real-time sensor system developed in our laboratory. While Ni microcantilevers produced no signal, ZnO nanostructure coated microcantilevers showed good sensitivity and repeatable changes. Furthermore, the nanotube coated microcantilevers showed more than 10 fold increase in sensitivity compared to the nanorod coated microcantilevers which can be explained to the fact that ZnO nanotubes have higher surface area and subsurface oxygen vacancies and these provide a larger effective surface area with higher surface-to-volume ratio as compared to ZnO nanorods. The tests are performed using dynamic mode of operation near resonant frequency using magnetic actuation and optical sensing. The phase stability and the limit of detection of ZnO nanotube coated microcantilevers exposed to diethylamine (DEA) were 0.02° and lower than 10 ppm, respectively. ZnO nanostructure coated microcantilevers have good potential for VOC sensor applications especially for amine groups. © 2014 Elsevier B.V. All rights reserved.European Research Council Siemens Türkiye Bilimler Akademisi 113F403, 111E184Necmettin Kilinc was supported by TUBITAK-BIDEB National Postdoctoral Research Fellowship Program. The authors thank KUYTAM and Dr. Barıs Yagci for SEM measurements. This research is supported by TUBITAK Grant no.: 111E184 and 113F403. Necmettin Kilinc received the B.Sc. degree from Marmara University, Istanbul, in 2003, and M.Sc. and Ph.D. degrees from Gebze Institute of Technology in 2006 and 2012, all in Physics, respectively. After his Ph.D., he started to post doc at Optical Microsystems Laboratory Koc University to research cantilever based biosensors. He is an assistant professor at Nigde University, Mechatronics Engineering Department, Nigde, Turkey. His research interests are fabrication of nanostructures and thin films of metal oxides and organic materials and structural and electrical properties of these materials and using these materials for bio-chemical sensor applications. Onur Cakmak received his B.Sc. degree in Mechanical Engineering from Istanbul Technical University and M.Sc. degree on Vibration Engineering from the same University in 2010. Between 2008 and 2010 he worked as an engineer in vibration & acoustics group at Arcelik Beko R&D Center, Istanbul, Turkey. During that period he took part in R&D projects on noise and vibration control of the products. In May 2011 he joined Optical Microsystems Research Laboratory at Koç University, Istanbul. He is taking part in Biosensor Project at under the supervision of Prof. Dr. Hakan Urey. Working on mechanical design and microfabrication of MEMS biosensor chips which are consisting of electromagnetically actuated microresonators working in liquid medium and microfluidic channels. Responsible for optimization of those design and microfabrication processes in order to obtain detection with high sensitivity. Arif Kosemen received his M.Sc. degree in physics from Gebze Institute of Technology in 2009. He is a research assistant at Department of Physics of Mus Alparslan University. His research interests are: organic solar cells and chromic devices. Erhan Ermek received his M.Sc. degree in Department of Biomedical Engineering from Baskent University in 2010. He is a senior research engineer in Optical Microsystems Research Laboratory at Electrical Engineering Department, Koç University, Istanbul. His research interests are: mass sensitive transducers such as cantilever and QCM, biosensors. Sadullah Ozturk received his M.Sc. degrees in physics from Gebze Institute of Technology in 2009. He is working as a research assistant in Department of Physics, Gebze Institute of Technology. He interest on fabrication and characterization metal oxide nanostructures. Yusuf Yerli received the B.Sc., M.Sc. and Ph.D. degrees from Ondokuz Mayıs University in 1987, 1995 and 2002 respectively, all in Physics. He is a professor at the Department of Physics, Yıldız Technical University, Istanbul, Turkey. His research interests are EPR, Magnetic properties, Transition Metal Ions, Free Radicals, Nano structures, Conducting Polymers, OLED, Organic Solar Cells, OFET, Electrochromic Device, Electrical Characterization. Zafer Ziya Ozturk is professor of solid-state physics at Gebze Institute of Technology, Turkey. He received his undergraduate education at Hacettepe University, Ankara, Turkey and the graduate education at the Technical University of Darmstadt, Germany, Ph.D. degree in 1982. He was a Postdoctoral Fellow at the Institute for Physical Chemistry, University of Tuebingen, Germany. He has held several research, teaching and scientist positions including University of Dicle, Diyarbakir, TUBITAK Marmara Research Center, Gebze and University of Marmara, Istanbul, Turkey. His research interests involve solid-state device sensors, molecular electronics, chemical and biochemical sensors. Hakan Urey received the B.Sc. degree from Middle East Technical University, Ankara, in 1992, and M.Sc. and Ph.D. degrees from Georgia Institute of Technology in 1996 and in 1997, all in Electrical Engineering. After completing his Ph.D., he joined Microvision Inc.-Seattle as Research Engineer and he played a key role in the development of the Retinal Scanning Display technology. He was the Principal System Engineer when he left Microvision to join the faculty of engineering at Koç University in 2001. He was promoted to Associate Professor in 2007 and Professor in 2010. He published about 50 journals and 100 international conference papers, 7 edited books, 4 book chapters, and has more than 25 issued and several pending patents. His research interests are in the area of optical MEMS, micro-optics and optical system design, 2D/3D display and imaging systems, and biosensors. He is a member of SPIE, IEEE, and OSA. He received an Advanced grant from the European Research Council (ERC-AdG) in 2013, Outstanding Faculty Award from Koç University in 2013, TÜBİTAK-Encouragement Award in 2009, Outstanding Young Scientist Award from the Turkish Academy of Sciences (TÜBA) in 2007, and Werner Von Siemens Excellence Award in 2006
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