18 research outputs found

    X-ray detector on 2U cubesat BeEagleSAT of QB50

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    BeEagleSAT is a 2 Unit cubesat to be launched within the EU FP7 project QB 50. It is been produced by Istanbul Technical University and Turkish Air Force Academy. Sabanci University will provide a CdZnTe based semiconductor X-ray detector and associated readout electronics. The detector will utilize cross strip geometry to test the detection system in space, but it will not carry a mask for imaging. The readout will be established by an application specific integrated circuit controlled by a microcontroller. The system will have its own battery and will be turned on intermittently due to power and telemetry constraints. It will characterize the hard X-ray background in 20-150 keV at low Earth orbit conditions as a function of altitude

    Conglomerateness: Size and Monopoly Control

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    The aim of this study is to evaluate the effects of sildenafil citrate on cisplatin-induced ovarian toxicity. Thirty-two female rats were divided into four groups. Group 1: saline control; group 2: cisplatin; group 3: sildenafil citrate; and group 4: cisplatin plus sildenafil citrate group. In groups 2 and 4, the rats were injected with 5 mg/kg cisplatin intraperitoneally (i.p.). In groups 3 and 4, the rats were injected with 1.4 mg/kg sildenafil citrate i.p. The ovaries were removed two weeks later in all groups. Histopathologic examination, follicle counting and classification were performed. The expression of anti-Mullerian hormone (AMH) was detected immunohistochemically in the ovarian tissues. Sildenafil alleviated cisplatin-induced histopathological changes in the ovarian tissue. Primordial, secondary and tertiary follicles were diminished in group 2 compared with group 1 (p <0.05). Pretreatment with sildenafil citrate preserved primordial follicle count in group 4 compared with group 2, and the difference was statistically significant (p <0.05). According to our results, immunoreactivity intensity of AMH was lower in group 2 compared with group 1 (92.4 +/- 3.97 versus 88.8 +/- 1.77) but not significantly, whereas immunoreactivity intensity of AMH was higher in group 4 compared with group 2 (88.8 +/- 1.77 versus 94.1 +/- 2.36; p<0.05). Our results demonstrated that pretreatment with sildenafil citrate is beneficial for protecting the ovaries from cisplatin-induced damage. Sildenafil citrate can be a choice for fertility preservation

    Development and in orbit testing of an x ray detector within a 2U cubesat

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    A CdZnTe based semiconductor X-ray detector (XRD) and its associated readout electronics is developed by the Space Systems Design Laboratory of Istanbul Technical University and High Energy Astrophysics Detector Laboratory of Sabanci University along with an SME partner. The detector will utilize 30 orthogonal cross strip electrodes (and 3 steering electrodes in between anodes) whose geometry is optimized by an extensive set of simulations and energy resolution measurements. The signals will be read by RENA 3b ASIC controlled by MSP 430 microcontroller. The system will have its own battery and will be turned on intermittently due to power constraints. CdZnTe based X-ray detectors have been utilized in space, but they are either pixellated (NuStar), or they consist of many individual crystal pieces (BAT in Swift satellite). The aim of the XRD is to show that large volume crystals with orthogonal strips are viable alternatives, especially for small satellite systems with medium energy resolution requirement. XRD will also characterize the hard X-ray background in 20-200 keV at low Earth orbit conditions as a function of altitude. Due to power and telemetry constraints, the individual events will be corrected for hole trapping on-board, histogrammed, and only the X-ray spectra will be transmitted to the ground station along with a small set of raw data for diagnostic purposes. The XRD is planned to travel into space, as a secondary science mission, on board BeEaglesat which is a 2U CubeSat developed as one of the possible double (2U) CubeSats for the QB50 project. QB50 is a European Framework 7 (FP7) project carried out by a number of international organizations led by the von Karman Institute of Belgium. Its main scientific objective is to study in situ the temporal and spatial variations of a number of key constituents and parameters in the lower thermosphere with a network of about 50 double and triple CubeSats, separated by few hundred kilometers and carrying a determined set of sensors

    X-ray detector XRD on BeEagleSat and the development of the improved x-ray detector iXRD

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    Many interesting astrophysical objects are intense X-ray emitters. Hard X-ray observatories in various sizes have been operating in space and providing exciting scientific results that we cannot obtain in our laboratories on Earth. Nanosatellites with CdZnTe hard X-ray detectors have been launched into orbit as well, and the future holds great promise with such small satellites contributing significantly to high energy astrophysics. One of those satellites is the BeEagleSat which carried the X-ray detector (XRD)to low Earth orbit. The XRD has a 15⨯15⨯3 mm 3 volume CdZnTe detector, a cross-strip electrode design, a RENA readout chip controlled by an MSP 430 microcontroller. Due to a communication problem with the receiver, no science data could have been downloaded from the XRD. Recently, an improved version of the XRD has been designed (called the iXRD)and currently it is in the production phase. The improvements compared to the XRD are the larger volume crystal with almost three times the collecting area, a collimator to limit the field of view for focused scientific return, and a motherboard-daughterboard design to reduce electronic noise

    Audit and Oversight of Audit in terms of Commerce Law of Turkey

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    While the rapid change brought by globalization of the economic life are enhancing world-wide the need for reliable and transparence information, the preparation of financial statement according to these two factors depends on establishing a unity between reporting standards and auditing applied around the world. Since 2005, stock market companies have started mandatory application of Turkish Accounting Standards (TASs), which is published in accordance with the International Financial Reporting Standards (IFRSs). Banking Regulation and Supervision Agency (BRSA) and Capital Markets Board (CMB) have taken very significant steps towards implementation of independent audit. A new Draft Turkish Commerce Law (TCL), as a replacement of the current TCL, has been prepared and it is now underway of becoming law. Moreover, according to draft TCL, Turkish Audit and Assurance Standards Board should be established. All of these developments perform with the object of secure transition from a tax oriented auditing view point to economic auditing point. The current study aims to reveal the development and current condition of auditing in Turkey and what have done in terms of keep up with international development.Audit; Oversight of audit; Draft Turkish Commerce Law; International Audit Standards; Turkish Accounting Standards; Corporate governance

    A rare case of bilateral complex odontomas: Clinical, radiological and histopathological findings

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    Odontoma is the most common odontogenic tumor that is radiographically and histologically characterized by the production of mature enamel, dentin, cementum and pulp tissue. It grows slowly and has nonaggressive behavior. This case report presents clinical, radiological and pathological findings of bilateral complex odontoma that is rarely in literature in a 30-year-old female patient

    Synthesis, aggregation and spectroscopic studies of novel water soluble metal free, zinc, copper and magnesium phthalocyanines and investigation of their anti-bacterial properties

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    AKCAY, Hakki Turker/0000-0002-8502-9608;WOS: 000340330900038PubMed: 24952089In this study, novel phthalonitrile derivative (3) was synthesized by the reaction between 4-nitrophthalonitrile (2) and a triazole derivative (1) containing pyridine moiety. Crystal structure of compound (3) was characterized by X-ray diffraction. New metal free and metallo-phthalocyanine complexes (Zn, Cu, and Mg) were synthesized using the phthalonitrile derivative (3). Cationic derivatives of these phthalocyanines (5, 7, 9, and 11) were prepared from the non-ionic phthalocyanines (4, 6, 8, and 10). All proposed structures were supported by instrumental methods. the aggregation behaviors of the phthalocyanines (4-11) were investigated in different solvents such as dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), chloroform and water. Water soluble cationic Pcs (5, 7, 9, and 11) aggregated in water and sodium dodecyl sulfate was used to prevent the aggregation. the second derivatives of the UV-Vis spectra of aggregated Pcs were used for analyzing the Q and B bands of aggregated species. Thermal behaviors of the phthalocyanines were also studied. in addition, anti-bacterial properties of the phthalocyanines were investigated. We used four gram negative and two gram positive bacteria to determine antibacterial activity of these compounds. Compound 7 has the best activity against the all bacteria with 125 mu g/mL of MIC value. Compounds 4, 6, and 10 have the similar effect on the bacteria with 250 mu g/mL of MIC value. (C) 2014 Elsevier B.V. All rights reserved
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