Publications with Fulltext

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/6

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Open Access
1899 yılı Osmanlı İmparatorluğu için jeomekansal ve çok modlu bir ulaşım ağı oluşturma denemesi
(Koç University Research Center for Anatolian Civilizations (ANAMED) / Koç Üniversitesi Anadolu Medeniyetleri Araştırma Merkezi (ANAMED), 2020) Gerrits, Piet; Department of History; Kabadayı, Mustafa Erdem; Özkan, Osman; Koçak, Turgay; Faculty Member; Teaching Faculty; Department of History; College of Social Sciences and Humanities; 33267; N/A; N/A
Open Access
3D-printed contact lenses: challenges towards translation and commercialization
(Future Medicine, 2022) Yetişen, Ali K.; Department of Mechanical Engineering; Taşoğlu, Savaş; Özdalgıç, Berin; Faculty Member; PhD Student; Department of Mechanical Engineering; KU Arçelik Research Center for Creative Industries (KUAR) / KU Arçelik Yaratıcı Endüstriler Uygulama ve Araştırma Merkezi (KUAR); Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); College of Engineering; Graduate School of Sciences and Engineering; 291971; 323683
NA
Open Access
A case of radiologically isolated syndrome developing Balo's concentric sclerosis lesions on long-term follow-up
(Elsevier, 2022) Danyeli, Ayça Ersen; Altıntaş, Ayşe; Çalışkan, İlay; Peker, Selçuk; Faculty Member; Faculty Member; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); School of Medicine; Graduate School of Health Sciences; Koç University Hospital; 11611; N/A; N/A; 11480
Background; Radiologically Isolated Syndrome (RIS) depicts a clinical scenario with multiple sclerosis (MS)-like magnetic resonance imaging (MRI) findings in individuals without clinical features of a demyelinating bout. Balo’s concentric sclerosis (BCS) on the other hand, is a variant of MS characterized by concentrically layered white mater demyelinating lesions. Case presentation: a 49-year-old male with an incidental brain lesion on MRI underwent a stereotactic biopsy and diagnosed as a demyelinating process. He remained asymptomatic throughout the long term clinical and radiological follow-up. However, the patient developed new demyelinating lesions with some showing concentric layers of BCS. Conclusion:this is the first reported case; to our knowledge, whereby a pathologically verified RIS patient developed characteristic BCS lesions. Our case highlights the heterogeneity of RIS as a clinico-radiological entity, requiring further sub-classification of the spectrum for improved management
Open Access
A community-based approach to prevention of pressure injuries: a study of the European Wound Management Association Research Grant
(European Wound Management Association (EWMA), 2021) Karadağ, Ayişe; Çakar, Vildan; Faculty Member; School of Medicine; Graduate School of Health Sciences; 3549; N/A
Pressure injuries (PIs) are important health problems all over the world because of their serious effects. Awareness of PIs and their effects has increased in recent years. Since patients’ relatives are part of the care team, they have an important role to play in the prevention of PIs. The most crucial aspect of the prevention of PIs is the education of healthcare professionals, patients and patients’ relatives and caregivers. This study aimed to educate caregivers on the prevention of PIs through the development of a digital game. With this purpose, we developed and used a technological education approach —a digital game— that employs gamification methods
Open Access
A critical approach to the biocompatibility testing of NiTi orthodontic archwires
(Vibgyor Online Publishers, 2016) Şahbazoğlu, D.; Toker, S. M.; Saher, D.; Department of Mechanical Engineering; Canadinç, Demircan; Gümüş, Berkay; Uzer, Benay; Yıldırım, Cansu; Polat-Altıntaş, Sevgi; Faculty Member; Department of Mechanical Engineering; College of Engineering; 23433; N/A; N/A; N/A; N/A
The biocompatibility of Nickel-Titanium (NiTi) archwires was investigated by simulating actual contact state of archwires around brackets, which enabled incorporation of realistic mechanical conditions into ex situ experiments. Specifically, archwires (undeformed, and bound to brackets on acrylic dental molds) were statically immersed in artificial saliva (AS) for 31 days. Following the immersion, the archwires and the immersion solutions were analyzed with the aid of variouselectron-optical techniques, and it was observed that carbon-rich corrosion products formed on both archwire sets upon immersion. The corrosion products preferentially formed at the archwire–bracket contact zones, which is promoted by the high energy of these regions and the micro-cracks brought about by stress assisted corrosion. Moreover, it is suggested that these corrosion products prevented significant Ni or Ti ion release by blocking the micro-cracks, which, otherwise, would have led to enhanced ion release during immersion. The current findings demonstrate the need for incorporating both realistic chemical and mechanical conditions into the ex situ biocompatibility experiments of orthodontic archwires, including the archwire-bracket contact.
Open Access
A note on weakly compact homomorphisms between uniform algebras
(Polish Academy of Sciences, 1997) Department of Mathematics; Ülger, Ali; Faculty Member; Department of Mathematics; College of Sciences
Open Access
A preliminary attempt to construct a geospatial, multimodal Ottoman transport network for 1899
(Koç University Press (KUP) / Koç Üniversitesi Yayınları (KÜY), 2021) Gerrits, Piet; Department of History; Kabadayı, Mustafa Erdem; Özkan, Osman; Koçak, Turgay; Faculty Member; Teaching Faculty; Department of History; College of Social Sciences and Humanities; 33267; N/A; N/A
Open Access
A wearable paper-integrated microfluidic device for sequential analysis of sweat based on capillary action
(Royal Society of Chemistry (RSC), 2022) Koydemir, Hatice Ceylan; Department of Mechanical Engineering; Department of Electrical and Electronics Engineering; Beker, Levent; Abbasiasl, Taher; Mirlou, Fariborz; İstif, Emin; Faculty Member; Department of Mechanical Engineering; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; 308798; N/A; N/A; N/A
Soft, skin-mounted microfluidic devices can collect microliter volumes of eccrine sweat and are capable of in situ real-time analysis of different biomarkers to assess physiological state and health. Chrono-analysis of sweat can be implemented to monitor temporal variations of biomarker concentrations over a certain period of interest. Conventional methods used to capture sweat or some of the newly developed microfluidic platforms for sweat collection and analysis are based on absorbent pads. They suffer from evaporation, leading to considerable deviations in the concentration of the biomarkers. Here, a paperintegrated microfluidic device is presented for sequential analysis of sweat that is easy to fabricate and does not include air exits for each reservoir, which reduces undesirable effects of sweat evaporation. Furthermore, the high capillary force of filter paper is leveraged to route the liquid into the chambers in a sequential fashion and allow further chemical analysis. The employed design of the paper-embedded microfluidic device successfully samples and analyzes artificial sweat sequentially for flow rates up to 5 ?L min?1 without showing any leakage. We demonstrated the performance of the device, employing colorimetric assays for chrono-analysis of glucose standard solutions at concentrations in the range of 10– 100 mM and pH of sweat during exercise. The results reveal the presented approach's functionality and potential to analyze the concentration of biomarkers over a certain period sequentially.
Open Access
Algeria’s manufacturing sector: few avenues to diversification
(The Lebanese Center for Policy Studies, 2017) Bustos, Sebastian; Department of Economics; Yıldırım, Muhammed Ali; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 219280
This policy report on Algeria’s industrial sector is the eighth in a series of reports aimed at identifying strategic options Arab countries have in undertaking structural transformation. Using the product space methodology, this report analyzes existing capabilities of selected economies by identifying products they currently export and determining which path they should follow to produce more sophisticated and strategic products. Algeria’s position in the product space suggests that the country’s future path for development should focus on new opportunities in the chemical and food clusters. Redeploying productive knowledge that already exists within the country into other more complex products would prove difficult but the current position implies that, unaided, the economy is unlikely to diversify. This suggests the need to adopt proactive industrial policies entailing a number of new industries or products at which to target public inputs.
Open Access
An empirical investigation of four well-known polynomial-size VRP formulations
(NA, 2018) Öncan, Temel; Department of Business Administration; N/A; Aksen, Deniz; Sadatizamanabad, Mirehsan Hesam; Faculty Member; Department of Business Administration; College of Administrative Sciences and Economics; Graduate School of Sciences and Engineering; 40308; N/A
This study presents an in-depth computational analysis of four well-known Capacitated Vehicle Routing Problem (CVRP) formulations with polynomial number of subtour elimination constraints: a node-based formulation and three arc-based (single, two- and multi-commodity flow) formulations. For each formulation, several valid inequalities (VIs) are added for the purpose of tightening the formulation. Moreover, a simple topology-driven granulation scheme is proposed to reduce the number of a certain type of VIs. The lower and upper bounding performance and the solution efficiency of the formulations and respective VI configurations are benchmarked with state-of-the-art commercial optimization software. The extensive computational analysis embraces 121 instances with up to 100 customer nodes. We believe that our findings could be useful for practitioners as well as researchers developing algorithms for the CVRP.
Open Access
An extensive comparative analysis of two MOF databases: high-throughput screening of computation-ready MOFs for CH4 and H2 adsorption
(Royal Society of Chemistry (RSC), 2019) Eruçar, İlknur; Department of Chemical and Biological Engineering; Keskin, Seda; Velioğlu, Sadiye; Altıntaş, Çiğdem; Avcı, Gökay; Harman, Hilal Dağlar; Azar, Ayda Nemati Vesali; Researcher; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; 40548; N/A; N/A; N/A; N/A; N/A
Computation-ready metal–organic framework (MOF) databases (DBs) have tremendous value since they provide directly useable crystal structures for molecular simulations. The currently available two DBs, the CoRE DB (computation-ready, experimental MOF database) and CSDSS DB (Cambridge Structural Database non-disordered MOF subset) have been widely used in high-throughput molecular simulations. These DBs were constructed using different methods for collecting MOFs, removing bound and unbound solvents, treating charge balancing ions, missing hydrogens and disordered atoms of MOFs. As a result of these methodological differences, some MOFs were reported under the same name but with different structural features in the two DBs. In this work, we first identified 3490 common MOFs of CoRE and CSDSS DBs and then performed molecular simulations to compute their CH4 and H2 uptakes. We found that 387 MOFs result in different gas uptakes depending on from which DB their structures were taken and we identified them as ‘problematic’ MOFs. CH4/H2 mixture adsorption simulations showed that adsorbent performances of problematic MOFs, such as selectivity and regenerability, also significantly change depending on the DB used and lead to large variations in the ranking of materials and identification of the top MOFs. Possible reasons of different structure modifications made by the two DBs were investigated in detail for problematic MOFs. We described five main cases to categorize the problematic MOFs and discussed what types of different modifications were performed by the two DBs in terms of removal of unbound and bound solvents, treatment of missing hydrogen atoms, charge balancing ions etc. with several examples in each case. With this categorization, we aimed to direct researchers to computation-ready MOFs that are the most consistent with their experimentally reported structures. We also provided the new computation-ready structures for 54 MOFs for which the correct structures were missing in both DBs. This extensive comparative analysis of the two DBs will clearly show how and why the DBs differently modified the same MOFs and guide the users to choose either of the computation-ready MOFs from the two DBs depending on their purpose of molecular simulations.
Open Access
An historical geographic information system for Ottoman Studies. The c. 1907 Ottoman Census and Armenian Settlement in Istanbul
(Peeters Online Journals, 2020) Ohanian, Daniel; Başkurt, Z. Mehmet; Department of History; Kabadayı, Mustafa Erdem; Faculty Member; Department of History; College of Social Sciences and Humanities; 33267
The purpose of this article is to announce the publication of a partial transcription of the c. 1907 Ottoman census that relates to 24,000 Apostolic Armenian Istanbulites and of a historical geographic information system (HGIS), or interactive map, that shows where these individuals lived. Within this framework, the authors first present their argument that an unidentified, microfilmed population register housed in New York is the most substantial portion of this census currently available to researchers. In the second part of their article, they introduce HGISes as tools for the digital humanities and describe the process of creating one.
Open Access
An improved lower bound on the competitive ratio of deterministic online algorithms for the multi-agent k-Canadian Traveler Problem
(Finding Press, 2022) Shiri, Davood; Department of Industrial Engineering; Salman, Fatma Sibel; Faculty Member; Department of Industrial Engineering; College of Engineering; 178838
We present an improved lower bound on the competitive ratio of deterministic online algorithms for the multi-agent k-Canadian Traveler Problem.
Open Access
Anne ve babası boşanan çocuğun soyadı ile ilgili Anayasa Mahkemesi’nin bireysel başvuru kararları hakkında ilk değerlendirmeler
(2017) N/A; Karaşahin, Yasin Alperen; Law School; 257378
Open Access
Arab country product space report introduction and methodology
(The Lebanese Center for Policy Studies, 2017) Bustos, Sebastian; Department of Economics; Yıldırım, Muhammed Ali; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 219280
During the decades prior to the Arab spring, Arab countries on average had one of the lowest per capita growth rates compared to other parts of the world. Although countries in the region registered higher growth rates at the beginning of the century, this economic growth did not bring about a structural transformation required to diversify Arab economies. The challenge remains not only in how to ensure these economies grow but also to ensure that growth is inclusive and sustainable. The general objective of the report is to lay out the strategic options Arab countries have in undertaking structural transformation. Using the product space methodology, the existing capabilities of selected economies are analyzed by locating products they currently export, which assists in determining which path they should follow to produce more sophisticated and strategic products.
Open Access
Artificial eye model and holographic display based IOL simulator
(Society of Photo-optical Instrumentation Engineers (SPIE), 2023) N/A; Department of Electrical and Electronics Engineering; N/A; Şahin, Afsun; Ürey, Hakan; Aygün, Uğur; Kavaklı, Koray; Akyazı, Deniz; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; School of Medicine; College of Engineering; Graduate School of Sciences and Engineering; 171267; 8579; N/A; N/A; N/A
Cataract is a common ophthalmic disease in which a cloudy area is formed in the lens of the eye and requires surgical removal and replacement of eye lens. Careful selection of the intraocular lens (IOL) is critical for the post-surgery satisfaction of the patient. Although there are various types of IOLs in the market with different properties, it is challenging for the patient to imagine how they will perceive the world after the surgery. We propose a novel holographic vision simulator which utilizes non-cataractous regions on eye lens to allow the cataract patients to experience post-operative visual acuity before surgery. Computer generated holography display technology enables to shape and steer the light beam through the relatively clear areas of the patient’s lens. Another challenge for cataract surgeries is to match the right patient with the right IOL. To evaluate various IOLs, we developed an artificial human eye composed of a scleral lens, a glass retina, an iris, and a replaceable IOL holder. Next, we tested different IOLs (monofocal and multifocal) by capturing real-world scenes to demonstrate visual artifacts. Then, the artificial eye was implemented in the benchtop holographic simulator to evaluate various IOLs using different light sources and holographic contents.
Open Access
Bank volatility connectedness in South East Asia
(2018) Department of Economics; Yılmaz, Kamil; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 6111
This paper presents an analysis of the volatility connectedness of major bank stocks in the South East Asia (SEACEN) region between 2004 and 2016. Applying the Diebold-Yilmaz Connectedness Index (DYCI) framework to daily stock return volatilities of major banks in the region, we obtain results that help us uncover valuable information on the region's static and dynamic bank volatility network. The volatility connectedness increased substantially during the US financial crisis (from 2007 to 2009) and during the European sovereign debt and banking crisis in 2011. The recent increase in the total connectedness has resulted from temporary financial shocks on a global scale. Once included in the analysis, the global systemically important banks (GSIBs) from the U.S. and Europe generate substantial volatility connectedness to SEACEN banks. We also identify country clusters in the banking volatility network. Major Indian, Taiwanese and Chinese banks generate volatility connectedness to their counterparts in other countries of the region. Finally, we show that the region's bank volatility network becomes tighter during systemic events; banks from different countries in the region generate volatility connectedness to the others.
Open Access
Being able to be mother: traditional practices of women in coping with infertility in Melekli Town of Iğdır
(2022) Çetinkaya Şimşek, Şahika; Eroğlu, Kafiye; Faculty Member; School of Nursing; 6061
Numerous traditional methods are used in the treatment of infertility around the world. The study of aim is to investigate the knowledge and experience of traditional methods by women to find solutions to infertility in Melekli Town in Iğdır. The research is a descriptive and cross-sectional study. The minimum sample size of the study was determined according to the formula of the incidence of the event in cases with a known population. The research was carried out with 214 women using face-to-face interview method in a town in the easternmost part of Turkey. The data were collected with a pen and ended questions form during the home visits to determine the socio-demographic characteristics of the women and their knowledge and experiences about the methods. The interviews lasted between 30- 45 minutes. Of the responding women, 85% had known traditional practice, and 9.3% had tried traditional methods. The traditional methods known by women to get pregnant were sitting on the vapor, intravaginal applications, vaginal application through the pad, applying heat in the abdominal area, drinking a mixture, wrapping the pelvic area. Having children is significantly affected the use of traditional practices (P < 0.05). Almost all the women participating in the study stated that they knew the traditional method to have children, and very few of them applied the traditional methods they knew to have children. / Dünyada infertilite tedavisinde çok sayıda geleneksel yöntem kullanılmaktadır. Bu çalışmanın amacı, Iğdır Melekli kasabasında yaşayan kadınların infertiliteye çözüm bulmak için kadınların geleneksel yöntemlerle ilgili bilgi ve deneyimlerini araştırmaktır. Araştırma tanımlayıcı ve kesitsel bir çalışmadır. Araştırmanın minimum örneklem büyüklüğü, popülasyonu bilinen olgularda olayın görülme sıklığı formülüne göre belirlenmiştir. Araştırma Türkiye’nin en doğusundaki yer alan Iğdır’ın Melekli kasabasında yüz yüze görüşme yöntemi kullanılarak 214 kadınla gerçekleştirilmiştir. Veriler, ev ziyaretleri sırasında kadınların sosyo-demografik özellikleri ve yöntemlere ilişkin bilgi ve deneyimlerini belirlemek için açık ve kapalı uçlu sorulardan oluşan form ile toplanmıştır. Görüşmeler 30-45 dakika arasında sürmüştür. Yanıt veren kadınların %85’i çocuk sahibi olabilmek için geleneksel yöntemleri bildiklerini ve %9,3’ü ise gebe kalmak için geleneksel yöntemleri denediğini belirtmiştir. Kadınların gebe kalmak için sıklıkla bildikleri geleneksel yöntemler; buhar üzerine oturma, doğrudan vajen içine yapılan uygulamalar, ped aracılığıyla yapılan vajinal uygulamalar, karın bölgesine ısı uygulama, karışım içme, pelvik bölgeyi sarma şeklindedir. Çocuk sahibi olmak için geleneksel uygulamaların kullanımını önemli ölçüde etkilemektedir (P<0.05). Çalışmaya katılan kadınların neredeyse tamamı çocuk sahibi olabilmek için geleneksel yöntemleri bildiğini ve çok az kısmı ise çocuk sahibi olmak için bildikleri geleneksel yöntemleri uyguladığını belirtmiştir.
Open Access
Çin’in yükselişi ve yeni kapitalizm
(Sosyoekonomi Society, 2018) Department of Sociology; Yörük, Erdem; Faculty Member; Department of Sociology; College of Social Sciences and Humanities; 28982
This article presents a theoretical discussion about the new forms of capitalism in the context of the economic and political rise of China. The article raises a discussion on the changes that the rise of China has instigated in both China and the world capitalism. This is considered in the context of mode of production, international trade, state and capital, by analysing China and capitalism from the perspective of long historical periods. In doing this, the article benefits from the work of and polemics between Giovanni Arrighi, Joel Andreas ve Richard Walker, who provided very important contemporary debates on this issue in the field of historical sociology.
Open Access
Clinical outcomes of salvage surgery in locally advanced distal rectal cancer patients with local regrowth following non-operative management
(Galenos Yayınevi, 2021) Özgür, İlker; Kulle, Cemil Burak; Keskin, Metin; Bozkurt, Halil Alper; Bayram, Melek; Acunaş, Bülent; Türker, Mehmet; Gürses, Bengi; Kapran, Yersu; Buğra, Dursun; Balık, Emre; Faculty Member; Faculty Member; Faculty Member; Faculty Member; School of Medicine; Koç University Hospital; 113169; 168101; 1758; 18758
Aim: locally advanced distal rectal cancer (LADRC) patients managed with non-operative management (NOM) with complete clinical response following neoadjuvant treatment will experience local regrowth in about 25% of cases. The long-term risks of this strategy or local regrowth treatment have not been well established, and the main concern is the probability of impaired oncological outcomes after salvage surgery. This study aimed to evaluate the feasibility and clinical outcomes of salvage surgery in LADRC patients with local regrowth following NOM. Method: all locally advanced, distal rectal cancer patients managed with NOM after neoadjuvant therapy with clinical complete response, who developed local regrowth during surveillance, between May 2016 and November 2018, were enrolled in the study. Patients were analyzed for the rate of salvage surgery, disease-free survival and overall survival. Results: eleven out of 63 (17.5%) patients developed local regrowth after a mean of 8.4 (3-15) months. The mean surveillance period was 31.8 (14- 50) months. Eleven (100%) patients underwent salvage surgery due to the principles of total mesorectal excision. LE was not performed. No patients experienced local recurrence and three out of eleven (27.3%) developed carcinomatosis peritonei and/or distant metastasis after a mean surveillance period of 12.2 (3-26) months. At 30 months, the local and/or systemic recurrence rate, disease-free survival, and overall survival in the patients undergoing surgical treatment were 100%, 73%, 73% and 91%, respectively. Conclusion: the vast majority of patients with regrowth following NOM were suitable for salvage surgery with curative intent and justifiable pelvic tumor control.