9 sonuçlar
Arama Sonuçları
Listeleniyor 1 - 9 / 9
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 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 Annular-ring CMUT arrays for forward-looking IVUS: Transducer characterization and imaging(IEEE, 2006-02) Değertekin, Fahrettin Levent; Güldiken, Rasim Oytun; Karaman, MustafaIn this study, a 64-element, 1.15-mm diameter annular-ring capacitive micromachined ultrasonic transducer (CMUT) array was characterized and used for forward-looking intravascular ultrasound (IVUS) imaging tests. The array was manufactured using low-temperature processes suitable for CMOS electronics integration oil a single chip. The measured radiation pattern of a 43 X 140- mu m(2) array element depicts a 40 degrees view angle for forward-looking imaging around a 15-MHz center frequency in agreement with theoretical models. Pulse-echo measurements show a -10-dB fractional bandwidth of 104% around 17 MHz for wire targets 2.5 mm away from the array in vegetable oil. For imaging and SNR measurements, RF A-scan data sets from various targets were collected using all interconnect scheme forming a 32-element array configuration. An experimental point spread function was obtained and compared with simulated and theoretical array responses, showing good agreement. Therefore, this study demonstrates that annular-ring CMUT arrays fabricated with CMOS-compatible processes are capable of forward-looking IVUS imaging, and the developed modeling tools can be used to design improved IVUS imaging arrays.Yayın Cross-group friendships and psychological well-being: A dual pathway through social integration and empowerment(Wiley, 2018-10-01) Bağcı Hemşinlioğlu, Sabahat Çiğdem; Türnüklü, Abbas; Bekmezci, EyüpThis study investigated the associations between cross-group friendships and psychological well-being among a sample of physically disabled adults. A total of 269 disabled people (M-age=39.13, SD=13.80; 114 females, 152 males, 3 unknown) completed questionnaires including the quality of their friendships with non-disabled people, perceived majority group's attitudes towards the minority group, collective self-esteem, collective action tendencies, own outgroup attitudes, and psychological well-being. Findings demonstrated that disabled people's cross-group friendships were directly and indirectly associated with higher levels of psychological well-being via two routes: one by promoting perceived majority attitudes which consequently led to more positive own outgroup attitudes (well-being through social integration hypothesis) and the other by leading to higher levels of collective self-esteem which enhanced collective action tendencies (well-being through empowerment hypothesis). Findings offer important insights into the study of cross-group friendships in relation to the psychological well-being of stigmatized minority group members.Yayın Turkish health policies: past, present, and future(Routledge, 2020-08-18) Oğuz, Ahmet BünyanIn this article, health policies in Turkey from the 1900s to the present are reviewed in light of the available data on the number of health institutions, life expectancy, infant mortality, and state budget allocation. While a significant quantitative development is observed in the provision of health services, the state by far maintained a leading role in the provision of health services until the 1980s, when an initially weak but steady deviation began, significantly increasing its pace from 2002 and creating a new path where the private sector raised its share with the extensive implementation of neoliberal economic policies. The emergence of public-private partnership projects as a financing tool in the health sector, with various models from the 1990s around the world, found its place in the Turkish health system in the form of city hospitals from 2013, creating a new deviation in the provision of health services by the state.Yayın Efficacy, all-cause discontinuation, and safety of serotonergic psychedelics and MDMA to treat mental disorders: a living systematic review with meta-analysis(Elsevier B.V., 2025-12) Højlund, Mikkel; Yılmaz Kafalı, Helin; Kırmızı, Begüm; Fusar-Poli, Paolo; Correll, Christoph U.; Cortese, Samuele; Sabé, Michel; Fiedorowicz, Jess; Saraf, Gayatri; Zein, Josephine; Berk, Michael; Husain, Muhammad I.; Rosenblat, Joshua D.; Rubaiyat, Ruby; Corace, Kim; Wong, Stanley; Hatcher, Simon; Kaluzienski, Mark; Yatham, Lakshmi N.; Cipriani, Andrea; Gosling, Corentin J.; Carhart-Harris, Robin; Tanuseputro, Peter; Myran, Daniel T.; Fabiano, Nicholas; Moher, David; Mayo, Leah M.; Nicholls, Stuart G.; White, Tracy; Prisco, Michele De; Radua, Joaquim; Vieta, Eduard; Ladha, Karim S.; Katz, Jay; Veroniki, Areti A.; Solmi, MarcoSerotonergic psychedelics and 3,4-methylendioxtmethamphetamine (MDMA) are promising treatments for mental disorders with a continuously evolving evidence base. We searched Pubmed/Scopus/clinical trial registries up to 08july2025 for double-blind randomized controlled trials (RCTs) testing MDMA or serotonergic psychedelics in patients with mental disorders. Primary outcomes were change in disease-specific symptoms and all-cause discontinuation. Standardized mean differences (SMD) and relative risk (RR) were estimated using random-effects meta-analysis. Risk of bias (RoB) was assessed with Cochrane’s RoB-tool version 2 and certainty of evidence with GRADE. The review is maintained as living systematic review ( https://ebipsyche-database.org/ ). We included 30 RCTs (1480 participants; female=45.8 %; with psychological support=83.3 %; high RoB=83.3 %). In post-traumatic stress disorder (PTSD), MDMA reduced PTSD symptoms compared to any control ( k = 11; SMD=-0.85 [-1.09; -0.60]; I2=0 %; GRADE=low). In major depressive disorder (MDD), psilocybin/ayahuasca/LSD reduced depressive symptoms ( k = 8; SMD=-0.62 [-0.97; -0.28]; I2=55 %; GRADE=very low). In anxiety disorders, both MDMA and serotonergic psychedelics reduced anxiety symptoms (SMDMDMA=-1.18 [-2.04; -0.32]; I2=0 %; k = 2; GRADE=low and SMDserotonergic=-0.88 [-1.70; -0.06]; I2=54 %; k = 5; GRADE=very low). In alcohol use disorder, neither psilocybin nor LSD reduced abstinence rates ( k = 6; RR=1.42 [0.89; 2.26]; I2=7 %; GRADE=very low). In attention-deficit hyperactivity disorder (ADHD), LSD did not reduce ADHD symptoms ( k = 1; SMD=0.22 [-0.32; 0.76]; GRADE=very low). Moderate certainty in evidence was only found for MDMA on PTSD symptoms when compared to placebo. MDMA/serotonergic psychedelics were not associated with higher risk of all-cause discontinuation (RRMDMA=0.74 [0.32; 1.72]; RRserotonergic=0.81 [0.56; 1.15]). Overall, MDMA/serotonergic psychedelics are promising for the treatment of PTSD, MDD, and anxiety disorders with moderate to large effect sizes. Pragmatic trials, long-term, head-to-head trials exploring the role of psychological support, aiming to identify predictors of response, and accounting for expectancy and functional unblinding are needed. Studies addressing these limitations will likely be required for regulatory approval of psychedelic drugs.
