Publications without Fulltext
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
Browse
13 results
Search Results
Publication Metadata only Bud14 function is crucial for spindle pole body size maintenance(TUBITAK, 2024) Department of Molecular Biology and Genetics; Girgin, Sevilay Münire; Çaydaşı, Ayşe Koca; Department of Molecular Biology and Genetics; College of Sciences; Graduate School of Sciences and EngineeringBackground/aim: Spindle pole bodies (SPB), the functional equivalent of centrosomes in yeast, duplicate through generation of a new SPB next to the old one. However, SPBs are dynamic structures that can grow and exchange, and mechanisms that regulate SPB size remain largely unknown. This study aims to elucidate the role of Bud14 in SPB size maintenance in Saccharomyces cerevisiae. Materials and methods: We employed quantitative fluorescence microscopy to assess the relative and absolute amounts of SPB structural proteins at SPBs of wildtype cells and in cells lacking BUD14 (bud14∆). Quantifications were performed using asynchronous cell cultures, as well as cultures synchronously progressing through the cell cycle and upon different cell cycle arrests. We also utilized mutants that allow the separation of Bud14 functions. Results: Our results indicate that higher levels of SPB inner, outer, and central plaque proteins are present at the SPBs of bud14∆ cells compared to wildtype cells during anaphase, as well as during nocodazole-induced M-phase arrest. However, during α-factor mediated G1 arrest, inner and outer plaque proteins responded differently to the absence of BUD14. A Bud14 mutant that cannot interact with the Protein Phosphatase 1 (Glc7) phenocopied bud14∆ in terms of SPB-bound levels of the inner plaque protein Spc110, whereas disruption of Bud14-Kel1-Kel2 complex did not alter Spc110 levels at SPBs. In cells synchronously released from α-factor arrest, lack of Bud14-Glc7 caused increase of Spc110 at the SPBs at early stages of the cell cycle. Conclusion: We identified Bud14 as a critical protein for SPB size maintenance. The interaction of Bud14 with Glc7, but not with the Kelch proteins, is indispensable for restricting levels of Spc110 incorporated into the SPBs. © TÜBİTAK.Publication Metadata only Exploration of novel 6,8,9-trisubstituted purine analogues: synthesis, in vitro biological evaluation, and their effect on human cancer cells(Tubitak Scientific & Technological Research Council Turkey, 2024) Polat, Muhammed Fatih; Atalay, Rengul; Tuncbilek, Meral; N/A; Şahin, İrem Durmaz; Koç University Research Center for Translational Medicine (KUTTAM); School of MedicineCancer, a leading global cause of mortality, demands continuous advancements in therapeutic strategies. This study focuses on the design and synthesis of a novel series of purine derivatives, specifically 6 -(substituted phenyl piperazine)-8-(4-phenoxyphenyl)9-cyclopentyl purine derivatives (5-11). The motivation behind this endeavor lies in addressing acquired resistance mechanisms in cancer cells, a significant hurdle in current treatment modalities. The synthesis, starting from 4,6-dichloro-5-nitropyrimidine, involves a multi -step process, resulting in seven new purine derivatives. Biological evaluation against human liver, colon, and breast cancer cells (Huh7, HCT116, and MCF7, respectively) was performed using the SRB assay. Among the synthesized analogs, compounds 5 and 6, exhibited notable cytotoxic activity, surpassing clinically used positive controls 5-Fluorouracil and Fludarabine in terms of efficacy. This research underscores the potential of purine derivatives with a phenyl group at the C-8 position as a scaffold for developing compounds with improved anticancer properties. The findings offer insights for future exploration and development of novel agents in cancer pharmaceutical research.Publication Metadata only Longitudinal attacks against iterative data collection with local differential privacy(Tubitak Scientific & Technological Research Council Turkey, 2024) Department of Computer Engineering; Gürsoy, Mehmet Emre; Department of Computer Engineering; College of EngineeringLocal differential privacy (LDP) has recently emerged as an accepted standard for privacy -preserving collection of users' data from smartphones and IoT devices. In many practical scenarios, users' data needs to be collected repeatedly across multiple iterations. In such cases, although each collection satisfies LDP individually by itself, a longitudinal collection of multiple responses from the same user degrades that user's privacy. To demonstrate this claim, in this paper, we propose longitudinal attacks against iterative data collection with LDP. We formulate a general Bayesian adversary model, and then individually show the application of this adversary model on six popular LDP protocols: GRR, BLH, OLR, RAPPOR, OUE, and SS. We experimentally demonstrate the effectiveness of our attacks using two metrics, three datasets, and various privacy and domain parameters. The effectiveness of our attacks highlights the privacy risks associated with longitudinal data collection in a practical and quantifiable manner and motivates the need for appropriate countermeasures.Publication Metadata only Growth and organotypic branching of lung-specific microvascular cells on 2D and in 3D lung-derived matrices(N/A, 2024) Özkan, Sena Nur; Öztürk, Ece; Graduate School of Health Sciences; School of MedicineTissue-specific endothelial cells have vital roles in maintenance and functioning of native tissues with constant reciprocal crosstalk with resident cells. Three-dimensional (3D) physio-mimetic in vitro models which incorporate lung-specific microvasculature are needed to model lung-related diseases which involve modulation of endothelial cell behavior like cancer. In this study, we investigated the growth kinetics, morphological changes and responses to biological cues of lung microvasculature on two-dimensional (2D) and in lung matrix-derived 3D hydrogels. HUVEC and HULEC-5a cells were cultured on 2D and compared for their growth, morphologies, and responses to varying growth medium formulations. Brightfield and immunofluorescence imaging was performed to assess differences in morphology. For 3D cultures, native bovine lungs were decellularized, lyophilized, solubilized, and reconstituted into hydrogel form in which endothelial cells were embedded. Cell growth and organotypic branching was monitored in 3D hydrogels in the presence of varying biological cues including lung cancer cell secretome. HUVEC and HULEC-5a cells demonstrated comparable growth and morphology on 2D. However, in 3D lung-derived ECM hydrogels, tissue-specific HULEC-5a cells exhibited much better adaptation to their microenvironment, characterized by enhanced organotypic branching and longer branches. HULEC-5a growth was responsive to lung cancer cell-conditioned medium in both 2D and 3D conditions. In 3D, the concentration of ECM ligand significantly affected cell growth in long-term culture where molecular crowding had an inhibitory role. Our data reveals that HULEC-5a cells offer a reliable alternative to frequently pursued HUVECs with comparable growth and morphology. Due to their intrinsic program for cellular crosstalk with resident cells, the use of tissue-specific endothelium constitutes a vital aspect for modeling physiological and pathological processes. Furthermore, our study is the first demonstration of the synergy between lung-specific microvasculature with lung-specific ECM within a 3D in vitro model.Publication Metadata only Materials anddevices for integrated room temperature quantum spintronics(Scientific and Technological Research Council of Turkey, 2021) Department of Electrical and Electronics Engineering; Onbaşlı, Mehmet Cengiz; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 258783Recent advances in precise stoichiometry control and high-resolution characterization of advanced spintronic materials allowed for the development of integrated spintronic devices, which might enable ultralow power magnonic devices with multi-THz spin wave bandwidth and topologically protected spin wavefunctions that are robust for fabrication imperfections. In addition, advances in microwave and optical excitation and control of quantum states in diamond nitrogen-vacancy systems (diamond-NV) allowed for ultrasensitive magnetometry and integrated quantum logic applications. Here, an integrated spintronic garnet/diamond-NV quantum system has been reviewed and discussed for logic and memory applications. After an overview of the recent advances in the growth and characterization of insulating magnetic iron garnets, previous computational demonstrations of ultrawide bandwidth topologically protected few-nanometer size chiral spin structures called skyrmions are discussed for carrying information on chip between diamond-NV systems. Next, earlier diamond-NV characterization studies using microwave ferromagnetic resonance and photoluminescence measurements were reviewed. Finally, a brief discussion is presented on the steps needed for integrated quantum spintronic devices to operate at room temperature.Publication Metadata only Anlysis of attrition patterns in the Turkish household labor force survey(Orta Doğu Teknik Üniversitesi / Middl East Technical Univesity, 2009) Department of Economics; Tunalı, Fehmi İnsan; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 105635This article offers an econometric analysis of attrition patterns in the "New" Turkish Household Labor Force Survey which has been conducted since 2000. A key feature of the redesigned survey is the short panel component which is obtained from four visits to the same address over a period of 18 months. We exploit the information in 12 quarters of micro data collected over the period 2000-2002 and study household and individual level attrition within 3, 12 and 15 months of the initial interview. Attrition is a phenomenon which is attributed to demographic and economic factors, including conditions in the labor market. If attrition is systematically related to the labor force status of individuals, this could result in biases in labor market indicators. . Our empirical investigation indeed provides strong evidence that attrition takes this non-ignorable form. The survey protocol allows interviews with substitute households or individuals who arrive at the designated address after the initial round. This practice appears to reduce the distortive influence of attrition. / Bu makale 2000 yılından beri toplanmakta olan “Yeni” Hanehalkı İşgücü Anketindeki kayıpranma örüntülerinin ekonometrik analizini içermektedir. Yeniden kurgulanan anketin temel özelliği aynı adrese 18 aylık bir dönemde dört ziyaret içermesiyle oluşan kısa panel boyutudur. Çalışmada 2000-2002 arasında 12 çeyrekten derlenen mikro veriler kullanılarak, ilk görüşmeden sonraki 3, 12 ve 15 aylık dönemde hane ve birey düzeyinde kayıpranma incelenmektedir. Kayıpranma işgücü pazarında karşılaşılan durumlar da dahil olmak üzere, bir dizi demografik ve ekonomik faktöre bağlanan bir olgudur. Kayıpranmanın bireylerin işgücü durumuyla sistematik bir ilişkisi olması işgücü istatistiklerinde yanlılığına yol açabilir. Nitekim ampirik sorgulamamız göz ardı edilemez bir kayıpranmanın varlığına işaret etmektedir. Anket protokolu adrese ilk ziyaretten sonra gelen hanehalkı ve bireylerle görüşme yapılmasına izin vermektedir. Bulgularımız bu uygulamanın kayıpranmanın yol açtığı yanlılığı bir miktar giderdiğine ilişkin ipuçları içermektedir.Publication Metadata only Governments’ policy agendas: an analysis of laws enacted since 1983(Yasama Derneği, 2020) Esen, Berk; Bektaş, Eda; Department of International Relations; Ekinci, Esra İşsever; Other; Department of International Relations; College of Administrative Sciences and Economics; N/AThis article studies the policy priorities of Turkish governments through an analysis of government-sponsored laws that were enacted in the parliamentary period between 1983 and 2015. The entire list of government-sponsored laws enacted over 32 years was coded according to the coding system of the “Comparative Agendas Project” (CAP). In this way, governments’ policy priorities are determined by measuring the overall legislative performances of the governments based on different issue areas of laws. First, the article assesses the impact of various factors such as government type (single party-coalition governments) and government duration on the variation in the overall legislative performance of governments. Second, it engages in a comparative analysis of the issue areas of laws and highlights similarities and differences in the policy priorities and the political agendas of different governments. This analysis also discusses the impact of factors emphasized in the literature such as inter-party competition, international organizations, and crises independent of governments on the policy agenda of Turkish governments. As the study focuses on the post-1983 period, the article’s findings provide a detailed assessment of Turkish politics over the last three decades. The article’s findings suggest that legislative performance is positively correlated with government duration and that singleparty governments with longer mandate in office generally have higher legislative performances than coalition governments. Furthermore, the article demonstrates that Turkish governments primarily enacted laws in the areas of international relations, state administration, macroeconomics, justice crime and family issues, and defense policy and hence prioritized these areas more than the others. / Öz: Bu makale, 1983 ve 2015 arası parlamenter dönemde kurulan hükümetlerin Meclisten geçerek yasalaşan kanun tasarılarını analiz ederek, farklı hükümetlerin politika önceliklerini incelemektedir. Yaklaşık 32 sene gibi uzun bir zaman diliminde çıkmış olan tüm kanunlar, Karşılaştırmalı Gündemler Projesi’nin (KGP) kodlama sistemi kullanılarak konu kapsamlarına göre kodlanmıştır. Bu sayede, hükümetlerin yasama performansları ölçülerek politika öncelikleri belirlenmektedir. Çalışmada ilk olarak, hükümetlerin çıkardıkları kanunlar üzerinden genel yasama performansları ve buna etki eden etmenler analiz edilmektedir. Bu analizde hükümet türü (tek partikoalisyon hükümetleri) ve hükümet süresi gibi değişkenlerin üzerinde durulmaktadır. İkinci olarak ise hükümetlerin çeşitli politika alanlarındaki yasama performanslarına odaklanılmakta ve farklı siyasi dinamikler altında kurulmuş olan hükümetlerin çıkardıkları kanunların konuları karşılaştırılmaktadır. Böylece, farklı hükümetlerin politika öncelikleri ve gündemleri ortaya konmaktadır. Bu analiz ayrıca literatürde vurgulanan partiler arası rekabet, uluslararası kuruluşlar, hükümetlerden bağımsız gerçekleşen krizler gibi değişkenlerin Türkiye’de hükümetlerin politika gündemine etkisini tartışmaktadır. Çalışma, 1983 sonrası döneme odaklandığından, elde edilen bulgular ve bunların Türk siyaseti üzerine olası çıkarımları temel olarak son 30 yıllık dönemin ayrıntılı bir siyasi portresini vermektedir. Çalışmanın bulguları, ilgili dönemde hükümetlerin kanunlara dayalı yasama performanslarının görev süresinden etkilendiğini ve tek parti hükümetlerinin politika oluşturma ve yasamayı etkileme kapasitesinin koalisyon hükümetlerine göre genel olarak daha yüksek olduğunu göstermektedir. Ayrıca, hükümetlerin sırasıyla uluslararası ilişkiler, devlet idaresi, makroekonomi, adalet suç ve aile meseleleri ve savunma politika alanlarında diğer alanlara göre daha çok kanun çıkardıkları ve dolasıyla bu alanları diğer politika alanlarına göre önceledikleri görülmektedir.Publication Metadata only Effect of maternal education on Turkish mother' styles of reminiscing with their children(Türk Psikologlar Derneği, 2004) Department of Psychology; Department of Psychology; Küntay, Aylin C.; Ahtam, Banu; Faculty Member; Undergraduate Student; Department of Psychology; College of Social Sciences and Humanities; College of Social Sciences and Humanities; 178879; N/AThis study investigates the relationship of maternal education to the style of mother-child conversations about past events. Previous research conducted in the US has identified two distinct styles of communication that mothers use to elicit talk about past events from their children (i.e., elaborative style and repetitive style), but the relationship of these patterns of talk to mothers’ education level has not been investigated. In this study, we recorded 22 mother-child pairs. of these, half included mothers of high educational background, and the other half had mothers of low educational background. Mothers’ child-directed utterances were coded in terms of their forms, contents, and relationships to the child’s responses. Results show that high-education mothers addressed more utterances per event to their children than low-education mothers. Also, child-directed speech of high-education mothers tended to be more elaborative and less repetitive than the speech of low-education mothers. One major contributor to this overall difference was that high-education mothers offered more elaborative statements than low-education mothers. The proportions of questioning behavior, on the other hand, were the same across the two groups of mothers. The pattern of differences found in the study could be explained by the longer exposure of high-education mothers to "classroom discourse" in addition to the potential facilitative effects of schooling on their communicative and narrative skills. / Öz: Bu çalışma, annelerin çocuklarıyla geçmişteki olaylar hakkında konuşma davranışlarıyla anne eğitim düzeyinin ilişkisini araştırmaktad›r. ABD’de yapılan araştırmalar, annelerin çocuklarıyla anıları hakkında konuşurken kullandığı ayrıntıcı (elaborative) ve tekrarcı (repetitive) olmak üzere iki ayrı konuşma biçimi belirlemiş, fakat bu stillerin annelerin eğitim düzeyleriyle ilişkisini incelememiştir. 11 yüksek ve 11 düşük eğitim düzeyli annenin, çocuklarına geçmiş olayları hatırlatmaya çalışırken geçen konuşmaları teybe kaydedilmiştir. Annelerin çocuklarına yönelik sözceleri (utterance), biçim, içerik ve çocuktan gelen yanıtla ilişkili olarak kodlanmıştır. Bulgularda, her iki gruptaki anneler de aynı sayıda olaydan bahsederken, yüksek eğitimli annelerin olay başına daha fazla sayıda sözce oluşturduğu görülmüştür. Ayrıca eğitim düzeyi yüksek annelerin, eğitim düzeyi düşük annelerle karşılaştırılınca, daha fazla ayrıntıcı ve daha az tekrarcı bir konuşma stili kullanma eğilimi gösterdikleri bulunmuştur. Bu farkın en önemli kaynağı kullanılan farklı soru oranları ve biçimleri değil, yüksek eğitimli anneler tarafından daha sıklıkla kullanılan olayların detaylarını betimleyen bildirim cümleleridir. Bulunan farklılıkların nedenleri olarak, annelerin eğitimlerinin uzunluğuyla ilişkili olarak geliştirdikleri "okul söylemiyle" tanıklıkkları ve bunun sonucunda edindikleri ayrıntıcı anlatı ve iletişim becerileri düşünülebilinir.Publication Metadata only Maliye bürokrasisinde örgütsel değişim ve Vergi Denetim Kurulu Başkanlığı'nın kurulması(Türkiye ve Orta Doğu Amme İdaresi Enstitusu, 2012) Department of International Relations; Bakır, Caner; Faculty Member; Department of International Relations; College of Administrative Sciences and Economics; 108141The establishment of Tax Inspection Administration (TIB) on 10 July 2011 signifies a revolutionary organizational change in fiscal bureaucracy in Turkey. This paper argues that organizational stability at the Ministry of Finance (MoF) has been punctuated by the determined government’s powerful intervention in organizational change. This revolutionary organizational change came swiftly, and subsequently affected the MoF bureaucracy as a whole. The research is a qualitative analysis of the TAB’s establishment. A combination of interviews and written sources was the main approach to data collection. The paper found that under the title of ‘tax auditor’, a new sub-identity has been introduced that aims to eliminate various bureaucratic subidentities generating conflict among tax inspectors board, inspection board of finance, budget and fiscal controllers and tax auditors. This change is likely to enhance state’s infrastructural capacity to levy and collect taxes via a progress towards an efficient and effective tax-collection machinery. It would facilitate further organizational reforms that faced the strong resistance of tax inspectors board and inspection board members. This paper also points to several policy challenges ahead on this course. / 10 Temmuz 2011 tarihinde Vergi Denetim Kurulu Başkanlığı’nın (VDKB) kurulması ile maliye bürokrasisinin vergi incelemesi yapan dört farklı mesleki alt-kimliğe mensup kadroları ve bunların bağlı oldukları kurul ve başkanlıklar kaldırılmıştır. VDKB’nin kuruluşu, hem Maliye Bakanlığı’nın örgütsel yapısında, hem de Türk mali denetim sisteminde devrimsel örgütsel değişimi getirmektedir. .itel araştırma tekniği kullanılan bu çalışmada, mülakatlardan ve yazılı kaynaklardan yararlanılmıştır. Bu çalışmanın temel bulgusu, VDKB’nin kurulması ile maliye bürokrasisinde “kast sistemi” olarak tanımlanan dengenin “güçlü ve kararlı siyasi irade” tarafından kesintiye uğraması sonucu maliye bürokrasisinde devrimsel örgütsel değişim yönünde bir adımın atıldığıdır.Publication Metadata only Women’s labor and indebtedness in Turkey: a focus on everyday experiences(Dipnot Basım Yayın, 2020) N/A; N/A; Kılınçarslan, Pelin; PhD Student; Graduate School of Social Sciences and Humanities; N/AIn the last decades, the use of credit cards and consumer loans has become a prominent phenomenon. Debt-based consumption is now such an ordinary practice that many households depend on credit to sustain basic needs. Lower-income groups in particular are forced into borrowing for the necessities of social reproduction, with credit operating as a neoliberal mode of inequality management. Easier availability of financial means, weak schemes of social protection, commodification of welfare services, and growing socioeconomic inequalities have all played a role in making credit a substitute for services once included in welfare provisions. Household indebtedness is therefore a complex phenomenon which stands at the nexus of the capitalist relations of production and social reproduction intertwined with class and gender inequalities. Given the key role women play in these processes, it is essential to explore the following questions: What kind of impact does indebtedness have on women’s labor within and beyond households? How does this impact unfold at the level of everyday experiences? How do these experiences connect to the changes taking place in broader relations of power, production and social reproduction? This paper aims to explore these questions by drawing on in-depth interviews with women who are residents of indebted households in Istanbul. Turkey provides an important context for studying women’s experiences of debt. In Turkey where household indebtedness is relatively a new phenomenon, household debt has increased by six times since the early 2000s and significantly concentrated among lowerincome groups. This study shows that indebtedness shapes the ways in which women undertake reproductive work and participate in formal/informal employment, and these practices are mediated by labor market patterns, welfare and employment regimes, and hegemonic constructions of motherhood and “housewife”. This operates both ways. on the one hand, debt burden reinforces gender inequalities in the labor market and the household. on the other, women’s labor plays a key role in the management of debt burden. / Hanehalkının kredi ve kredi kartı kullanımı son yıllarda dikkat çekici niteliktedir. Borca dayalı tüketim o denli yaygınlaşmıştır ki günümüzde pek çok aile, gündelik ihtiyaçlarını karşılayabilmek için krediye bağımlı hâle gelmiştir. Toplumsal yeniden üretimin artan maliyeti özellikle düşük gelir gruplarını borçlanmaya zorlamakta ve bu süreçte kredi, neoliberal bir eşitsizlik yönetimi aracına dönüşmektedir. Finansal araçlara erişimin kolaylaşması, sosyal güvenlik sisteminin zafi eti, kamusal hizmetlerin metalaşması ve derinleşen sosyoekonomik eşitsizlikler neticesinde kredi mekanizmaları, önceden kısmen devletin himayesinde olan refah uygulamalarının bir ikamesi olmaktadır. Dolayısıyla hanehalkı borçluluğu, kapitalist üretim ve toplumsal yeniden üretim ilişkilerinin temelinde şekillenen, sınıf ve toplumsal cinsiyet eşitsizlikleriyle örülü, karmaşık bir meseledir. Bu bağlamda, kadınların borçluluğu nasıl deneyimlendiğine bakmak ve şu soruları sormak oldukça önemlidir: Borçluluk, toplumsal yeniden üretimin belirleyici öznesi olan kadınların hane içinde veya dışında emeğe katılım süreçlerini nasıl etkilemektedir? Bugünü belirsiz bir yarına bağlayan borçluluk durumu, kadınların gündelik hayatlarında nasıl açığa çıkmaktadır? Bu deneyimler; üretim, toplumsal yeniden üretim ve güç ilişkileri bağlamında neye tekabül etmektedir? Bu çalışma, bahsi geçen soruları İstanbul’da borçlu hanelerden kadınlarla yapılan görüşmelere dayanarak yanıtlamayı hedeflemek edir. 2000’li yılların başından itibaren hanehalkı borçlanma oranının altı kat arttığı, borçluların çoğunluğunu alt sınıfla ın oluşturduğu ve kadın emeğinin daha yoğun baskılarla karşılaştığı Türkiye’de, kadınların deneyimlerine yer vermek özellikle önemlidir. Mülakatlar gösteriyor ki borçluluk, kadınların ücretli/ücretsiz emeğe ve enformel/formel işgücüne katılımlarını veya katılım biçimlerini etkilemektedir. Üstelik kadınların buradan doğan deneyimleri, emek piyasasının ve sosyal politikaların cinsiyetçi yapısının yanı sıra ailedeki cinsiyet rolleri ve annelik ya da “ev kadınlığına” atfedilen manalar aracılığıyla şekillenmektedir. Bu noktada borçluluk ve kadın emeği arasında iki yönlü bir ilişki ortaya çıkmaktadır: Bir taraftan borç yükü, kadın emeğinin hane içi ve emek piyasasındaki eşitsiz konumunu pekiştirirken diğer taraftan kadın emeği, borç yüküyle başa çıkabilmenin önemli bir dayanağı olmaktadır.