A highly resilient and zone-based key predistribution protocol for multiphase wireless sensor networks

Pairwise key distribution among the sensor nodes is an essential problem for providing security in Wireless Sensor Networks (WSNs). The common approach for this problem is random key predistribution, which suffers from resiliency issues in case of node captures by adversaries. In the literature, the resiliency problem is addressed by zone-based deployment models that use prior deployment knowledge. Another remedy in the literature, which is for multiphase WSNs, aims to provide self-healing property via periodic deployments of sensor nodes with fresh keys over the sensor field. However, to the best of our knowledge, these two approaches have never been combined before in the literature. In this paper, we propose a zone-based key predistribution approach for multiphase WSNs. Our approach combines the best parts of these approaches and provides self-healing property with up to 9-fold more resiliency as compared to an existing scheme. Moreover, our scheme ensures almost 100% secure connectivity, which means a sensor node shares at least one key with almost all of its neighbors

Determination of Attitudes on Gender: a Study on Higher Education Students

In this study, it’s aimed to specify the perspectives, attitudes and the awareness levels of university students on gender. 7,200 students studying at Cumhuriyet University and staying at the Credit and Dormitories Institution constitute the population of the study. Samples selected by random sample method are determined to be 370 individuals. 370 individuals, 185 women and 185 men, have participated in the study, and their average age was 21.47. The monthly income of 62.1% of these students was less than 500 TL, 68.4% of them had a nuclear family type and 43.5% of them has resided in the city center. 68.9% of students have stated that men and women aren’t equal while 37.8% have stated that this inequality arises from the structure of society, 22.4% have stated that the biggest challenge of women is violence and 73.8% have stated that women and men have equal amount of task share for the sexual equality. The results obtained by this study show that when all aspects related to gender roles concerning working life (Table 6), social life (Table 7) and family life (Table 8) of the students are examined, it is observed that male students have a more traditional viewpoint compared to female students and female students have a traditional viewpoint in propositions concerning married life (Table 8)

Role of bcl-2 family members in 4-hne induced apoptosis

In this study we have investigated the role of Bcl-2 protein family members in response to 4-HNE induced apoptosis by using endothelial cells and monocytes as models for atherosclerosis. Cell viability and Annexin-V staining experiments demonstrated that 4-HNE was cytotoxic for both human umbilical vein endothelial cells (huv-ec-c's) and human leukemic monocyte lymphoma cell line (U937 cells) and induced apoptosis in a dose dependent manner. In order to gain further insight into the apoptotic mechanism, the protein levels of Bcl-2 family members were investigated by immunoblot analysis. In 20 μM 4-HNE treated huv-ec-c's, Bcl-XL and Bax were upregulated within 4 hours of treatment, followed by a sharp decrease in the prosurvival Bcl-2 protein. Among proapoptotic members of the Bcl-2 family; Bid truncation occurred prior to Bcl-2 down-regulation. In 20μM of 4-HNE treated U937 cell line for 12 hours, Bcl-XL was downregulated at an early time point of 2 hours, then restored back to control level at the 4th hour, whereas prosurvival Bcl-2 had a sharp decrease in a time dependent manner. Contrary to Bcl-2 and BC1-XL, the protein level of Mcl-1 did not change in 12 hours time after 4-HNE treatment. The proapoptotic member of Bcl-2 family, Bax was upregulated however Bak, responsible for pore formation on the mitochondria membrane, was downregulated after the 4-HNE treatment in 2 hours time. In 10μM of 4-HNE treated U937 cell line for 24 hours, Bcl-XL down-regulation took place between 2 to 8 hours and Bcl-2 was downregulated at 2 to 12 hours then Bcl-XL and Bcl-2 protein levels were reestablished at 12 hours and 24 hours respectively. Mcl-1 and Bak protein levels did not change. Bax was also upregulated similar to high dose treatment. Protein levels of Bim and Bid were also studied by immunoblotting and were not found to change In our experimental system, several cell lines (huv-ec-c's and U937 cells) and several Bcl-2 family proteins' levels (Among prosurvival; Bcl-2, Bcl-XL and Mcl-1, among proapoptotics; Bax, Bak, Bid, Bim) were studied in response to 4-HNE treatment. Shortly, Bcl-2 proteins mainly responded in cell specific manner. Among these proteins, in huv-ec-c's BC1-XL and Bax were upregulated, Bcl-2 was downregulated. In U937 cells, Bcl-XL and Bcl-2 were downregulated at early time points, Mcl-1 level remained the same whereas Bax was upregulated. Only Bak protein responded in dose dependent manner in monocytes. In order to enlighten the role of Bak in the apoptotic mechanism, further investigations are necessary. Finally, these results indicate the involvement of mitochondrial pathway and sequential activation of Bcl-2 family proteins in high and low doses of 4-HNE induced apoptosis in two different cell lines

A novel role for 5-hmC in the regulation of cancer testis gene expression in cancer and mesenchymal to epithelial transition

Cataloged from PDF version of thesis.Includes bibliographical references (leaves 93-100).Thesis (Ph.D.): Bilkent University, The Department of Molecular Biology and Genetics and the Graduate School of Engineering and Science of Bilkent University, 2014.Cancer/testis (CT) genes show highly restricted expression among normal tissues, limited to germ cells in the testis and ovary, and to trophoblast cells, , but are frequently expressed in various cancers. Other than a clear association with promoter-specific demethylation and histone deacetylation, the specific mechanisms by which these genes are expressed are currently unknown. In this study, we tested various mechanisms including promoter- and region-specific epigenetic mechanisms to gain a better understanding of CT gene expression. To better study the epigenetic mechanisms regulating CT gene expression, we searched for a model that dynamically expresses CT genes. As a result of preliminary bioinformatic efforts and literature search, we chose to study CT gene expression in Caco-2 spontaneous differentiation model. We showed that PAGE-2,-2B and SPANX-B genes were up-regulated significantly as Caco-2 cells differentiated. Differentiation was also characterized as a mesenchymal to epithelial transition as evidenced by the decrease in mesenchymal markers (Fibronectin1, Vimentin and Transgelin) and the concomitant increase in epithelial markers (E-cadherin, Claudin 4 and Cdx2). CT protein (SPANX-B and PAGE-2,-2B) positive cells were positive for epithelial protein (Cdx2), and negative for mesenchymal proteins (Fibronectin1, Vimentin). Although we could not find a significant difference in promoter proximal DNA demethylation of CT genes, we identified that promoter proximal DNA was hydroxymethylated with a gradual increase in hydroxymethylation as cells differentiated. The change in hydroxymethylation level was concordant with an increase in TET enzyme levels and co-localization of TET2 protein with CT proteins in the corresponding cells. Besides, we found that promoters of CT genes lost EZH2, H3K27me3 and HP1 marks as CT genes were up-regulated. Reversal of differentiation resulted in loss of CT and TET gene expression and EMT induction. Thus, for the first time, we describe dynamic expression of CT genes in association with DNA hydroxymethylation in mesenchymal to epithelial transition. In addition to promoter-proximal alterations, we thought that epigenetic alterations leading to CT gene expression in cancer could occur within larger regions containing CT v genes, but with clear boundaries. As genes that do not show an expression pattern similar to CT genes can be located within their proximity, we hypothesized that there could be clear boundaries between neighbouring regions containing CT genes and those with non-CT type expression patterns. We, therefore, identified 2 genes; ALAS2 and CDR1, in close proximity to two different CT genes (PAGE-2,-2B and SPANX-B), which were downregulated in cancer, and thus showed an expression pattern opposite to that of these two CT genes. ALAS2 and CDR1 were downregulated in lung and colon cancer cell lines compared to healthy counterparts. We found that the downregulation of ALAS2 and CDR1 in cancer cell lines, in contrast to CT genes, was independendent of DNA hypomethylation. We also found that ALAS2 and CDR1 downregulation in cancer was possibly related to decreased levels of hydroxymethylation in promoter proximal regions. As the upregulation of PAGE-2,-2B and SPANX-B genes was associated with increased hydroxymethylation at promoter-proximal regions, these two groups of genes, despite their close proximity were found to be controlled inversely albeit possibly by the same mechanisms. We tested if ectopic upregulation of ALAS2 and CDR1 in cancer cell lines would result in a tumor-suppressive effect, but were unable to find any. As both genes are located about 200 and 50 kbs from SPANX-B and PAGE-2, we propose that the there might be a boundary within these regions that could possibly have an insulatorlike function to help distinguish the two very different epigenetic events occuring in tumorigenesis. As almost all CT genes map within highly homologous inverted repeats it is possible that 3 dimensional chromosomal structures formed around these repeats underlie the common epigenetic mechanism responsible for coordinate CT gene expression. To test for this hypothesis, we analyzed expression of various transcripts identified within and outside the NY-ESO-1 repeat region. However, we could not find a correlation between the presence of such transcripts and CT gene expression patterns.by Sinem Yılmaz Özcan.Ph.D

Ytterbium doped all-fiber integrated high power laser systems and their applications

Ankara : The Department of Physics and the Graduate School of Engineering and Science of Bilkent University, 2013.Thesis (Master’s) -- Bilkent University, 2013.Includes bibliographical references leaves 61-66.For the past decades, high-power laser technology has been developing rapidly all over the world. The scientific interest in fiber lasers stems from the rich nonlinear dynamics. Industrial interest is largely due to their practical advantages, such as high power levels, compact size, relatively low cost, excellent beam quality, over established laser technologies. As a result, fiber laser are highly sought after in applications including material processing, especially in high-precision micromachining with ultrafast pulses, medical applications and defence applications, especially for the high power and efficiency levels that fiber laser can offer. The advantage of fiber lasers for high powers is largely due to their geometry, which is a very long cylinder, with an extremely high surface to volume ratio, rendering heat transfer away from the active medium much easier. Fiber lasers diffraction-limited beam quality if operating in the fundamental fiber mode. Average output powers that can be extracted from singlemode fiber lasers can reach up to a few kilowatts without serious thermal problems due to the fiber structure. For many realworld applications, misalignment free operation is important and an all-fiber laser system offers this prospect, but to date, most of the published reports on high-power lasers utilise bulk optics components to couple light in and out of fibers, which detracts from some of the practical advantages of fiber lasers. Ytterbium doped fibers which are preferred as active media for high-power operation, as the technology behind it has led to the development of excellent components and the small quantum defect is extremely useful for high-power applications. Yb-doped continuous wave lasers practically can reach several kilowatt levels, yet the output power of Yb-doped picosecond and sub picosecond pulsed lasers with a small count of bulk optics in the cavity have been limited to several hundred watts. In this thesis, we mainly focus on developing two high-power, robust, fiberintegrated lasers systems. The first system is a laser designed for continuous-wave (cw) operation, reaching up to 200 W level. The second system is a picosecondpulsed system, delivering 100-W, few-ps pulses at 100 MHz repetition rate. The latter is built based on master oscillator power amplifier (MOPA) structure. The multi-stage amplifier of the pulsed system and resonator design for the continuous wave laser system are both based on the all-fiber designs which allow for robust operation and have been optimised through numerical simulations. We expect these systems to find widespread use in material processing applications.Yılmaz, Saniye SinemM.S

100 Temel Eser Uygulamasının Öğrencilerin Okuma Alışkanlıklarına Etkisi ve Bu Uygulamada Kütüphanelerin Rolü Konusunda Öğretmen Görüşleri

This study aims to evaluate the effects of 100 Essential Reading Application which was put into effect by the Ministry of National Education of the 59th Government in 2005 on students’ reading habits. In addition, it tries to find out the effect of libraries on this application in relation to the views of primary Turkish teachers. A questionnaire was conducted to 141 teachers working in 54 primary schools in county of Çankaya, Mamak and Yenimahalle in Ankara. The results show that the application is not very successful with respect to the main elements of the study. The findings of the study also reveal the teachers’ view about the application. According to them, the application is not ‘very convenient’ and it is not proper to make 100 Essential Reading obligatory for students because this obligation causes them to dislike the books in the list. In addition, teachers think that students do not read 100 Essential Reading willingly and tastefully and school libraries and classroom libraries do not function effectively in this application.Bu çalışma, Milli Eğitim Bakanlığı’nın (MEB), 59. Hükümet döneminde kabul edilen ve 2005 yılında başlatılan 100 Temel Eser Uygulamasının öğrencilerin kitap okuma alışkanlıkları üzerinde etkilerini ve özellikle kütüphane unsurunun bu uygulamadaki işlevini ilköğretim Türkçe öğretmenlerinin görüşleri çerçevesinde değerlendirilmeyi hedeflemiştir. Çalışma kapsamında Ankara’nın Çankaya, Mamak ve Yenimahalle ilçelerinde 54 ilköğretim okulunda görev yapan 141 öğretmene anket uygulanmıştır. Elde edilen bulgular uygulamanın ele alınan unsurlar açısından genel olarak çok başarılı olmadığını ortaya koymuştur. Çalışmada elde edilen bulgulara göre, öğretmenler, 100 Temel Eserin öğrenciler için ”çok uygun” olduğunu düşünmemekte, 100 Temel Eserin okutulmasının zorunlu tutulmasını genelde yanlış bulmakta ve bunun öğrencilerde bu eserlere karşı soğukluk yarattığını belirtmektedirler. Onlara göre, öğrencilerin 100 Temel Eseri istek ve zevkle okumamakta, okul kütüphaneleri ve sınıf kitaplıkları 100 Temel Eser Uygulamasında yeterli işlev görememektedirler

Clinical diagnosis and complications of paratubal cysts: review of the literature and report of uncommon presentations

Paraovarian or paratubal cysts (PTCs) constitute about 10 % of adnexial masses. Although they are not uncommon; they rarely cause symptoms and are usually incidentally found. Actual incidence is not known. The symptoms occur when they grow excessively, or in case of hemorrhage, rupture or torsion. Here, literature review reporting the incidence, presentation and complications of PTCs is performed. Uncommon presentations of PTCs in three different cases, a giant PTC, torsion of PTC and borderline paratubal tumor, are also reported and discussed. Ultrasonography, CT or MRI may be performed in preoperative evaluation; but none of these imaging techniques have specific criteria for diagnosis. So, in most cases misdiagnosis as an ovarian mass remains to be a problem. Paratubal cysts can become extremely big before causing symptoms. Torsion is another urgent issue regarding PTCs, necessiating urgent surgery for preservation of the ovary and the tube. Although malignancy is rare, borderline paratubal tumors have been reported in the literature

The levels of matrix metalloproteinase-9 and neutrophil gelatinase-associated lipocalin in different stages of endometriosis

This study was designed to explore matrix metalloproteinase-9 (MMP-9), neutrophil gelatinase-associated lipocalin (NGAL) levels and MMP-9/NGAL ratio in women with and without endometriosis diagnosed surgically and/or histopathologically. The correlation between biomarkers and the severity of the disease is analysed. The revised American Fertility Society classification system was used to determine the severity of endometriosis. Serum MMP-9 and Ca125, urine NGAL levels were measured in all participants. Serum MMP-9 levels were significantly higher in the study group (n¼60) compared to controls (n¼31) (15.0 pg/mL (6.0–143.0) vs. 12.0 (4.0–18.0), respectively; p¼.002). MMP-9 levels were significantly higher in severe endometriosis compared to mild endometriosis subgroups (p<.001). No significant difference was found between NGAL levels in study and control groups (p>.05). The diagnostic value of MMP-9 and NGAL is not superior than CA-125 for endometriosis. Nevertheless, MMP-9 might be a potential predictive marker for advanced stage of the disease

Effects of chromosomal translocations on sperm count in azoospermic and oligospermic cases

Purpose: A number of mechanisms have been proposed for the effect of chromosomal translocations on spermatogenesis and sperm maturation. However, there are still numerous ambiguous issues regarding these two processes. The aim of this study is to evaluate the effect of chromosome break areas on sperm count in the light of the literature. Material and Methods: The study was conducted on the data of 16 male patients with reciprocal or Robertsonian translocation among 152 patients who were admitted to Adana Numune Training and Research Hospital and Kanuni Sultan Suleyman Training and Research Hospital Genetic Diagnosis Centers between 2013 and 2016 due to azoospermia and oligospermia. Results: 11 of these patients had reciprocal and five patients had Robertsonian translocations. All the patients with Robertsonian translocations were detected with azoospermia. Of the patients with reciprocal translocation, five of them were azoospermic and six of them were severe oligospermic. Conclusion: A total of 21 chromosomal breakpoints were identified in the 11 patients with reciprocal translocations. These chromosomal breakpoints may contribute to the clarification of ambiguous issues related to spermatogenesis and sperm maturation. The results also showed the importance of genetic counselling in patients with translocations

Hemodynamic outcome of different ventilation modes in laparoscopic surgery with exaggerated trendelenburg: a randomised controlled trial

Purpose: To compare hemodynamic effects of two different modes of ventilation (volume controlled and pressure-controlled volume guaranteed) in patients undergoing laparoscopic gynecology surgeries with exaggerated Trendelenburg position. Methods: Thirty patients undergoing laparoscopic gynecology operations were ventilated using either volume-controlled (Group VC) or pressure-controlled volume guaranteed mode (Group PCVG) (n = 15 for both groups). Hemodynamic variables were measured using Pressure Recording Analytical Method by radial artery cannulation in addition to peak and mean airway pressures and expired tidal volume. Results: The only remarkable finding was a more stable cardiac index in Group PCVG, where other hemodynamic parameters were similar. Expired tidal volume increased in Group VC while peak airway pressure was lower in Group PCVG. Conclusion: PCV-VG causes less hemodynamic perturbations as measured by Pressure Recording Analytical Method (PRAM) and allows better intraoperative hemodynamic control in exaggerated Trendelenburg position in laparoscopic surgery