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Yayın Vapor-induced film formation from low-T-g particles for different solvent compositions(Elsevier Inc, 2006-05-15) Arda, Ertan; Kara, Selim; Saraç, Ayfer; Pekcan, Mehmet ÖnderThe photon transmission method was used to study latex film formation from poly(vinyl acetate) (PVAc) particles induced by two different solvents. Films with the same latex content were prepared from PVAc particles and exposed to vapor of ethanol-water and acetone-water mixtures in various compositions. Transmitted photon intensities, I-tr, from these films increased with increasing vapor exposure time. The increase in I-tr is attributed to the increase in crossing density at the polymer-polymer junction. The Prager-Tirrell model was employed to obtain the back-and-forth frequency, v, of the reptating polymer chain during film formation induced by solvent vapor. It was observed that the produced v values increase as the solvent content is increased for both solvents. Abilities of both solvents to form films were interpreted with the solubility parameters of the solvents and the PVAc.Yayın Volumetric ultrasound imaging using 2-D CMUT arrays(IEEE-Inst Electrical Electronics Engineers Inc, 2003-11) Oralkan, Ömer; Ergün, Arif Sanlı; Cheng, Ching-Hsiang; Johnson, Jeremy A.; Karaman, Mustafa; H. Lee, Thomas; Khuri-Yakub, Butrus ThomasRecently, capacitive micromachined ultrasonic transducers (CMUTs) have emerged as a candidate to overcome the difficulties in the realization of 2-D arrays for real-time 3-D imaging. In this paper, we present the first volumetric images obtained using a 2-D CMUT array. We have fabricated a 128 x 128-element 2-D CMUT array with through-wafer via interconnects and a 420-mum element pitch. As an experimental prototype, a 32 x 64-element portion of the 128 X 128-element array was diced and flip-chip bonded onto a glass fanout chip. This chip provides individual leads from a central 16 X 16-element portion of the array to surrounding bondpads. An 8 x 16-element poition of the array was used in the experiments along with a 128-channel data acquisition system. For imaging phantoms, we used a 2.37-mm diameter steel sphere located 10 mm from the array center and two 12-mm-thick Plexiglas plates located 20 mm and 60 mm from the array. A 4 X 4 group of elements in the middle of the 8 X 16-element array was used in transmit, and the remaining elements were used to receive the echo signals. The echo signal obtained from the spherical target presented a frequency spectrum centered at 4.37 MHz with a 100% fractional bandwidth, whereas the frequency spectrum for the echo signal from the parallel plate phantom was centered at 3.44 MHz with a 91% fractional bandwidth. The images were reconstructed by using RF beamforming and synthetic phased array approaches and visualized by surface rendering and multiplanar slicing techniques. The image of the spherical target has been used to approximate the point spread function of the system and is compared with theoretical expectations. This study experimentally demonstrates that 2-D CMUT arrays can be fabricated with high yield using silicon IC-fabrication processes, individual electrical connections can be provided using through-wafer vias, and flip-chip bonding can be used to integrate these dense 2-D arrays with electronic circuits for practical 3-D imaging applications.Yayın A stochastic risk-averse framework for blood donation appointment scheduling under uncertain donor arrivals(Springer, 2020-12) Yalçındağ, Semih; Baş Güre, Seda; Carello, Giuliana; Lanzarone, EttoreBlood is a key resource in all health care systems, usually drawn from voluntary donors. We focus on the operations management in blood collection centers, which is a key step to guarantee an adequate blood supply and a good quality of service to donors, by addressing the so-called Blood Donation Appointment Scheduling problem. Its goal is to employ appointment scheduling to balance the production of blood units between days, in order to provide a reasonably constant supply to transfusion centers and hospitals, and reduce non-alignments between physicians' working times and donor arrivals at the collection center. We consider a two-phase solution framework taken from the literature, in which a deterministic linear programming model preallocates time slots to different blood types and a prioritization policy assigns the preallocated slots to the donors when they make a reservation. However, the problem is stochastic in nature and requires consideration of the uncertain arrivals of non-booked donors. In this work, to include the uncertain arrivals, we propose three stochastic counterparts of the preallocation model based on a risk-neutral objective and two risk-averse objectives, respectively, where the Conditional Value-at-Risk is considered as the risk measure in the last two methods. The resulting stochastic frameworks have been tested considering the historical data of one of the largest Italian collection centers, the Milan Department of the "Associazione Volontari Italiani Sangue" (AVIS). Results show the effectiveness of the stochastic models, especially the mean-risk one, and the need to include the uncertainty of arrivals in order to better balance the production of blood units.Yayın Computational model of the ventricular action potential in adult spontaneously hypertensive rats(2003-09-01) Padmala, Srikanth; Demir, Sıddıka SemahatIntroduction: Cardiac hypertrophy has substantial clinical significance because many hypertrophic cells have markedly prolonged repolarization behavior, which may lead to increased risk for cardiac arrhythmias. Spontaneously hypertensive rat (SHR) is one model of hypertension that is studied extensively and is considered to be the best laboratory model of human hypertension. We extended our previously published model of the rat ventricular myocyte to simulate the effects of hypertrophy in SHR. Methods and Results: In SHR it has been shown that the membrane capacitance is increased, the density of transient outward K+ current is decreased, the sarcoplasmic reticulum Ca 2+ ATPase activity is reduced, and the cell volumes are increased compared to those of the normal rat. We introduced these changes into our previous model of the rat ventricular myocyte and simulated the ventricular action potential of SHR. Our results demonstrated increased action potential duration (APD) and increased peak systolic value of the intracellular calcium transient in SHR. Simulations with reduced extracellular K+ concentration ([K+]o) have shown that there is increased APD shortening in SHR compared to that of the normal rat. Conclusions: Our computational model qualitatively simulated the electrophysiologic changes observed in SHR and provided the plausible mechanistic linkage between the prolonged APD and increased inotropy. Our model results also demonstrated the electrophysiologic changes observed with reduced [K+]o in SHR, a finding that is clinically significant in hypertensive patients with left ventricular hypertrophy undergoing diuretic treatment.Yayın Imagined contact facilitates acculturation, sometimes: contradicting evidence from two sociocultural contexts(Educational Publishing Foundation-American Psychological Assoc, 2019-10) Bağcı Hemşinlioğlu, Sabahat Çiğdem; Piyale, Zeynep Ecem; Stathi, SofiaObjective: Imagined intergroup contact has been shown to be an effective tool to improve intergroup relationships in various settings, yet the application of the strategy among minority group members and across cultures has been scarce. The current research aimed to test imagined contact effects on minority group members' acculturation strategies (contact participation and culture maintenance), perceived discrimination, feelings of belongingness, and social acceptance across three studies conducted in the United Kingdom (Study 1) and Turkey (Studies 2 and 3). Method: The sample consisted of Eastern Europeans in Study 1 (N = 63) and Kurds in Study 2 and 3 (N = 66 and 210, respectively). Participants were randomly assigned to 1 of 2 conditions (control vs. imagined contact) and completed measures of acculturation, perceived discrimination, general belongingness, and social acceptance. Results: Findings showed that while imagined contact significantly reduced perceived discrimination and culture maintenance, and increased contact participation and social acceptance among Eastern Europeans (Study 1), it reduced social acceptance and contact participation among Kurds recruited from a conflict-ridden homogeneous setting (Study 2). With a larger and more heterogeneous sample of Kurds (Study 3), these effects occurred only among those with higher ingroup identification. Moreover, in all studies social acceptance mediated the effects of imagined contact on contact participation and perceived discrimination. Discussion. Findings offer important insights about the use of the imagined contact strategy among minority group members and imply the need to take into account the context-dependent nature of contact strategies.Yayın Evolutionary route to diploidy and sex(National Academy of Sciences, 2001-11-20) Tüzel, Erkan; Sevim, Volkan; Erzan, AyşeBy using a bit-string model of evolution, we find a successful route to diploidy and sex in simple organisms. Allowing the sexually reproducing diploid individuals to also perform mitosis, as they do in a haploid-diploid cycle, leads to the complete takeover of the population by sexual diploids. This mechanism is so robust that even the accidental conversion and pairing of only two diploids give rise to a sexual population.Yayın Pedestrian crossing behavior at midblock crosswalks(Elsevier Ltd, 2019-12) Tezcan, Hüseyin Onur; Elmorssy, Mahmoud; Aksoy, GökerIntroduction: This study investigated the pedestrian crossing behavior at midblock crosswalks, in Istanbul. Method: Data were compiled from field studies at four selected crosswalks that were on one-way streets. Three of the crosswalks were located on three-lane streets while the other one was on a two-lane street. By using two-hour video recordings at each crosswalk, information was collected about pedestrian crossing preferences, pedestrian platoons both at curbside and during the crossing, traffic characteristics including volume, crosswalk occupancy and illegal parking, and pedestrian characteristics comprising age, gender and distraction status. These data were stratified with respect to the number of lanes and two multinomial logit models for platooning and individual crossing behavior was estimated for each stratum. Results: The results showed that the likelihood of platooning increases as the traffic volume and platoon size increase. Moreover, pedestrians who waited for little or no at the curbside and started to cross when one or more lanes were occupied generally lost time during the crossing. In terms of policy, the formation of platoons should be prevented by enforcement or demand-responsive traffic signals with push-to-walk buttons, etc. Overall, the study revealed that the presence of midblock crosswalks is questionable.Yayın Forward-viewing CMUT arrays for medical Imaging(IEEE-INST Electrical Electronics Engineers Inc, 2004-07) Demirci, Utkan; Ergün, Arif Sanlı; Oralkan, Ömer; Karaman, Mustafa; Khuri-Yakub, Butrus ThomasThis paper reports the design and testing of forward-viewing annular arrays fabricated using capacitive micromachined ultrasonic transducer (CMUT) technology. Recent research studies have shown that CMUTs have broad frequency bandwidth and high-transduction efficiency. One- and two-dimensional CMUT arrays of various sizes already have been fabricated, and their viability for medical imaging applications has been demonstrated. We fabricated 64-element, forward-viewing annular arrays using the standard CMUT fabrication process and carried out experiments to measure the operating frequency, bandwidth, and transmit/receive efficiency of the array elements. The annular array elements, designed for imaging applications in the 20 MHz range, had a resonance frequency of 13.5 MHz in air. The immersion pulse-echo data collected from a plane reflector showed that the devices operate in the 5-26 MHz range with a fractional bandwidth of 135%. The output pressure at the surface of the transducer was measured to be 24 kPa/V. These values translate into a dynamic range of 131.5 dB for I-V excitation in 1-Hz bandwidth with a commercial low noise receiving circuitry. The designed, forward-viewing annular CMUT array is suitable for mounting on the front surface of a cylindrical catheter probe and can provide Doppler information for measurement of blood flow and guiding information for navigation through blood vessels in intravascular ultrasound imaging.Yayın Anti-tobacco control industry strategies in Turkey(BioMed Central Ltd, 2018-02-26) Keklik, Seda; Gültekin Karakas, DeryaBackground: Transnational tobacco companies (TTCs) penetrated the Turkish cigarette market due to trade and investment liberalization in the post-1980 period and eventually secured full control. Despite tobacco control policies put in place in reaction to accelerating consumption, TTCs reinforced their market power through a variety of strategies. This paper explores industry strategies that counteract tobacco control policies in Turkey. Methods: The study employs both qualitative and quantitative analyses to explore industry strategies in Turkey. Besides the content analyses of industry and market reports, descriptive analyses were conducted for the sub-periods of 1999-2015. The analyses focus on the market strategies of product innovation, advertisement-promotion, cost management and pricing. Results: Rising sales of low tar, ultra-low tar, slim, super-slim and flavoured cigarettes indicate that product innovation served to sustain consumption. Besides, the tobacco industry, using its strong distribution channels, the Internet, and CSR projects, were found to have promoted smoking indirectly. The industry also rationalized manufacturing facilities and reduced the cost of tobacco, making Turkey a cigarette-manufacturing base. Tobacco manufacturers, moreover, offered cigarettes in different price segments and adjusted net prices both up and down according to price categories and market conditions. In response to the successful effect of shifts in price margins, the market share of mid-priced cigarettes expanded while those within the economy category maintained the highest market share. As a result of pricing strategies, net sales revenues increased. Aside from official cigarette sales, the upward trends in the registered and unregistered sales of cigarette substitutes indicate that the demand-side tobacco control efforts remain inadequate. Conclusions: The Turkish case reveals that the resilience of the tobacco industry vis-a-vis mainstream tobacco control efforts necessitates a new policy perspective. Rising market concentration by TTCs and the global nature of industry strategies require that the highly profitable manufacturing and trade of tobacco products should be discouraged on a basis of international collaboration. To reduce and eventually eradicate tobacco consumption, supply-side tobacco control measures are needed along with demand-side policies.Yayın Olanzapin kullanımına bağlı çekilme diskinezisi ve süpersensitivite psikozu(Turkish Neuropsychiatric Society, 2016-06) Karaş, Hakan; Güdük, Mehmet; Saatçioğlu, İbrahim ÖmerTardive dyskinesia (TD) usually appears after years of antipsychotic drug use and appears to be related to the total lifetime medication dose. In withdrawal-emergent dyskinesia (WE-D), which is considered to be a subtype of TD, dyskinetic symptoms often appear shortly after a rapid reduction in antipsychotic drug dose or sudden discontinuation of the drug. Supersensitivity psychosis, which is frequently observed along with TD and is considered to have a similar etiology as TD, is a psychotic relapse phenomenon that occurs after the withdrawal of an antipsychotic drug or a rapid reduction in the drug dosage. In general, atypical antipsychotics tend to be associated with less propensity to cause TD when compared with typical antipsychotics. Furthermore, olanzapine and clozapine may have a therapeutic potential in improving or totally curing TD. In this study, a case of WE-D because of discontinuing olanzapine use and supersensitivity psychosis is discussed.
