468 research outputs found
Near-Optimal Feedback Guidance for Low-Thrust Earth Orbit Transfers
No full textThis research proposes a near-optimal feedback guidance based on nonlinear control for low-thrust Earth orbit transfers. For the numerical simulations, two flight conditions are defined: (i) nominal conditions and (ii) nonnominal conditions that account for the orbit injection errors and the stochastic failures of the propulsion system. Condition (ii) is studied through an extensive Monte Carlo Analysis, to demonstrate the nonlinear feedback guidance’s numerical stability andconvergence properties. To illustrate the performance under both conditions, an orbit transfer from low Earth orbit to geostationary orbit is considered. Near-optimality of the feedback guidance comes from carefully selecting the nonlinear control gains. Comparison of the transfer with an existing study that uses optimal control reveals that orbit transfers based on feedback orbit control are very close to the optimal solution.Control & Simulatio
The Separation of the beauty and love with semiolojik method
No full textBu tezin, veri tabanı üzerinden yayınlanma izni bulunmamaktadır. Yayınlanma izni olmayan tezlerin basılı kopyalarına Üniversite kütüphaneniz aracılığıyla (TÜBESS üzerinden) erişebilirsiniz.IV YÜKSEK LİSANS TEZ ÖZETİ HÜSNÜ AŞK'IN GÖSTERGEBÎLİM YÖNTEMİYLE ÇÖZÜMLENİŞİ Yasemin ATMACA Türk Dili ve Edebiyatı Anabilim Dalı Afyon Kocatepe Üniversitesi Sosyal Bilimler Enstitüsü Eylül 2004 Danışman:H.Feridun GÜVEN Çalışmada, XVTJI. yüzyıl şairlerinden Şeyh Gâlib'in Hüsn ü Aşk adlı mesnevisi, Eski Türk Edebiyatı alanında yeni olan bir yöntemle incelenmiştir. Bu yöntem, "GÖstergebilim" olup Eski Türk Edebiyatı alanında uygulanabilirliğini saptamak amacıyla kullanılmıştır. Yöntem, Algirdas Julien Greimas'ın ortaya koyduğu üç düzeyli bir inceleme yöntemidir. Bu yöntemin, Hüsn ü Aşk'a uygulanmasıyla, Eski Türk Edeoiyatı'mn romanları sayılan mesnevilerde de rahatlıkla uygulanabileceği görülmüştür.ABSTRACT THE SEPARATION OF THE BEAUTY AND LOVE WITH SEMIOLOJIC METHOD Yasemin ATMACA Turkish Language and Literature Main Science Department Afyon Kocatepe University Social Science Institute September 2004 Supervisor: Ast. Doç. H. Feridun GÜVEN In this study, "Hüsn ü Aşk" mesnevi ( poem in rhymed couplets ) of 18th century poet Şeyh Galib is studied with a new method in the field of Old Turkish Literature. The method is "semiotics" and it is used to prove its applicability in Old Turkish Literature. The method is a three leveled research technique which was put forward by Algirdas Mien Greimas. By the use of this method on "Hüsn ü Aşk", it has been seen that the method can easily be applied on the mesnevis which are considered as the novels of the Old Turkish Literature
Photovoltaic-thermal system for building application: a case study
No full textIn buildings today, there is also a need of thermal energy, besides electrical energy. Hot air and hot water are forms of thermal energy that can be used in buildings. PV/T systems help produce these shapes of energies with the use of solar power. In this study, the supply of the required energy in buildings produced by a PV/T system, using two working fluids - air and water - has been investigated. The studies were conducted on typical winter, spring, and summer days which had different atmospheric conditions. At the same time, the amount of electrical and thermal energy gained between the selected intervals on those days was also investigated. The results show that the energy obtained in three different ways from a PV/T module are well high. The produce of hot air can be used as a residential need in winter. The results also show that a great portion of the need to heat a typical office up to 59% and to provide 55% of hot water consumption for one person on a daily basis in only 1 h can be provided by such a PV/T module. Additionally, the energy which is gained from air is well high in summer and can be used for other purposes by way of optimization. On the other hand, the production of electrical energy and hot water can also be used for residential needs in all seasons
Left ventricular mass in a Simmental calf: cavernous haemangioma
No full textDINCEL, Gungor Cagdas/0000-0002-6985-3197; Terzi, Osman Safa/0000-0002-7877-8897; ATMACA, HASAN TARIK/0000-0001-8379-4114
Stress distribution comparisons of foot bones in patient with tibia vara: a finite element study
No full textugur, levent/0000-0003-3447-3191; OZKAN, Arif/0000-0002-1288-6166; Celik, Talip/0000-0003-0033-2454; Atmaca, Halil/0000-0001-5820-6456WOS: 000332507000009PubMed: 24479742Blount's disease, or tibia vara, is the most common cause of pathologic genu varum in children and adolescents. Changes in the loading of knee structures such as tibial articular cartilage, menisci and subcondral bone are well documented in case of genu varum. But the mechanical effects of this condition on foot bones are still questionable. In this study, the authors hypothesized that stress distributions on foot bones might increase in patients with tibia vara when compared with patients who had normal lower extremity mechanical axis. Three-dimensional (3D) finite element analyses of human lower limb were used to investigate and compare the loading on foot bones in normal population and patient with tibia vara. The segmentation software, MIMICS was used to generate the 3D images of the bony structures of normal and varus malalignment lower extremity. Except the spaces between the adjacent surface of the phalanges fused, metatarsals, cuneiforms, cuboid, navicular, talus and calcaneus bones were independently developed to form foot and ankle complex. Also femur, tibia and fibula were modeled utilizing mechanical axis. ANSYS version 14 was used for mechanical tests and maximum equivalent stresses (MES) were examined. As a result of the loading conditions, in varus model MES on talus, calcaneus and cuboid were found higher than in normal model. And stress distributions changed through laterally on middle and fore foot in varus deformity model
Trastuzumab in combination with AT-101 induces cytotoxicity and apoptosis in Her2 positive breast cancer cells
No full textAim: AT-101 is a polyphenolic compound with potent anti-apoptotic effects in various cancers. In this study, the possible synergistic cytotoxic and apoptotic effect of trastuzumab/AT-101 combination was investigated in HER2-positive breast cancer cell lines. Materials & methods: SKBR-3, MDA-MB-453 and MCF-10A cell lines were treated with a trastuzumab/AT-101 combination. Synergistic cytotoxicity and apoptosis effects were shown and then PI3K and Akt protein levels were studied. Result: The trastuzumab/AT-101 combination induced synergistic cytotoxicity and apoptosis in both breast cancer cells but not in MCF-10A cells. Combination treatment induced cytotoxicity via inhibiting PI3K/AKT but not the MAPK/ERK pathway. Conclusion: The trastuzumab/AT-101 combination may be a good candidate for patients with trastuzumab-resistant Her2-positive breast cancer and inhibition of the PI3K/AKT pathway may be one of the underlying mechanisms. © 2019 Gulcan Bulut, Harika Atmaca & Burcak Karaca
Ginkgo Biloba Extract (EGb 761) Protects The Mice Brain Against Fluoride-Induced Oxidative Stress
No full textATMACA, HASAN TARIK/0000-0001-8379-4114The aim of this study was to investigate the effects of Ginkgo biloba extract (EGb 761) on oxidative stress and the histopathological changes in brain tissues of mice exposed to fluoride administration. A total of 24 mice were divided into 4 groups as control, EGb 761, fluoride and fluoride+EGb 761, with 6 mice in each group. Control group received drinking water, fluoride group received 50 mg/L fluoride in drinking water, fluoride+EGb 761 group was given 50 mg/L fluoride in drinking water and 20 mg/kg EGb 761 orally by gavage, and EGb 761 group was given only 20 mg/kg EGb 761 orally by gavage for 30 days. At the end of the experimental period, the levels of malondialdehyde (MBA) and glutathione (GSH) as well as' the activities of superoxide dismutase (SOD) and catalase (CAT) were detected, and histopathological examination was conducted in the brain of mice. The results showed that the levels of MDA, GSH, and the activities of SOD and CAT in fluoride group were statistically higher than in the control group. However, no statistically significant difference was detected between fluoride+EGb 761 and control group. The neurodejenerative changes seen in fluoride group were not detected in fluoride+EGb 761 group. It was concluded that the toxic effect of fluoride was related to the formation of reactive oxygen species, and EGb 761 had a protective effect by preserving antioxidant enzymes activity in mice brain tissues. Ginkgo biloba extract also prevented the histopathological changes induced by fluoride administration
Ratlarda deneyselolarak oluşturulan flor toksikasyonu üzerine resveratrolün koruyucu etkisinin araştırılması
No full textProje -- Kırıkale Üniversitesi2011/4490743
New histone deacetylase inhibitors as potential therapeutic tools for advanced prostate carcinoma
No full textThe anti-epileptic drug valproic acid is also under trial as an anti-cancer agent due to its histone deacetylase (HDAC) inhibitory properties. However, the effects of valproic acid (VPA) are limited and concentrations required for exerting anti-neoplastic effects in vitro may not be reached in tumour patients. In this study, we tested in vitro and in vivo effects of two VPA-derivatives (ACS2, ACS33) on pre-clinical prostate cancer models. PC3 and DU-145 prostate tumour cell lines were treated with various concentrations of ACS2 or ACS33 to perform in vitro cell proliferation 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and to evaluate tumour cell adhesion to endothelial cell monolayers. Analysis of acetylated histones H3 and H4 protein expression was performed by western blotting. In vivo tumour growth was conducted in subcutaneous xenograft mouse models. Tumour sections were assessed by immunohistochemistry for histone H3 acetylation and proliferation. ACS2 and ACS33 significantly up-regulated histone H3 and H4 acetylation in prostate cancer cell lines. In micromolar concentrations both compounds exerted growth arrest in PC3 and DU-145 cells and prevented tumour cell attachment to endothelium. In vivo, ACS33 inhibited the growth of PC3 in subcutaneous xenografts. Immunohistochemistry and western blotting confirmed increased histone H3 acetylation and reduced proliferation. ACS2 and ACS33 represent novel VPA derivatives with superior anti-tumoural activities, compared to the mother compound. This investigation lends support to the clinical testing of ACS2 or ACS33 for the treatment of prostate cancer
High Photosensitized Singlet Oxygen Generating Zinc and Chloroindium Phthalocyanines Bearing (4-isopropylbenzyl)oxy Groups as Potential Agents for Photophysicochemical Applications
No full textIn this study, novel phthalonitrile derivatives (1 and 2) and their peripherally and non-peripherally tetra (4-isopropylbenzyl)oxy-substituted zinc and chloroindium phthalocyanine complexes (3-6) have been prepared for the first time. The synthesized phthalonitrile derivatives and phthalocyanine complexes were characterized spectroscopically. Not only the chloroindium phthalocyanines but also zinc phthalocyanines are essentially free from aggregation in THF at the studied micromolar concentration. The purpose is to compare the effects of two types of substitution on the phthalocyanines to be used as sensitizers in photodynamic therapy (PDT). Photophysical and photochemical properties of all phthalocyanines are investigated and the results showed that the peripheral phthalocyanines more effectively photooxidize DPBF through singlet oxygen. The photochemical results showed that both ZnPc (3 and 5) and InPc (4 and 6) can be used as sensitizers in PDT because of their very high singlet oxygen quantum yields (range from 0.80 to 0.97)
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