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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/6
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Publication Open Access A stochastic representation for mean curvature type geometric flows(Institute of Mathematical Statistics (IMS), 2003) Touzi, N.; Department of Mathematics; Soner, Halil Mete; Faculty Member; Department of Mathematics; College of Administrative Sciences and EconomicsA smooth solution {Gamma(t)}(tis an element of[0,T]) subset of R-d of a parabolic geometric flow is characterized as the reachability set of a stochastic target problem. In this control problem the controller tries to steer the state process into a given deterministic set T with probability one. The reachability set, V(t), for the target problem is the set of all initial data x from which the state process X-X(v)(t) is an element of T for some control process v. This representation is proved by studying the squared distance function to Gamma(t). For the codimension k mean curvature flow, the state process is dX(t) = root2P dW(t), where W(t) is a d-dimensional Brownian motion, and the control P is any projection matrix onto a (d - k)-dimensional plane. Smooth solutions of the inverse mean curvature flow and a discussion of non smooth solutions are also given.Publication Open Access Multidimensional wave packet dynamics within the fluid dynamical formulation of the Schrodinger equation(American Institute of Physics (AIP) Publishing, 1998) Rabitz, H.; Department of Mathematics; Aşkar, Attila; Dey, Bijoy K.; Faculty Member; Faculty Member; Department of Mathematics; College of Sciences; 178822; N/AThis paper explores the quantum fluid dynamical (QFD) representation of the time-dependent Schrodinger equation for the motion of a wave packet in a high dimensional space. A novel alternating direction technique is utilized to single our each of the many dimensions in the QFD equations. This technique is used to solve the continuity equation for the density and the equation for the convection of the flux for the quantum particle. The ability of the present scheme to efficiently and accurately describe the dynamics of a quantum particle is demonstrated in four dimensions where analytical results are known. We also apply the technique to the photodissociation of NOCl and NO2 where the systems are reduced to two coordinates by freezing the angular variable at its equilibrium value.Publication Open Access TRMU-related transient liver failure of infancy presents with microcephaly and neurodevelopmental delay(Nature Publishing Group (NPG), 2019) N/A; N/A; Azaklı, Hülya; Börklü Yücel, Esra; Arıkan, Çiğdem; Armutlu, Ayşe; Eraslan, Serpil; Kayserili, Hülya; PhD Student; Faculty Member; Teaching Faculty; Researcher; Graduate School of Health Sciences; School of Medicine; N/A; N/A; N/A; N/A; N/A; 7945Publication Open Access Preparation of Pt/Al2O3 and PtPd/Al2O3 catalysts by supercritical deposition and their performance for oxidation of nitric oxide and propene(Elsevier, 2020) Şanlı Yıldız, D.; Özener, B.; Hisar, G.; Rommel, S.; Aindow, M.; Department of Chemical and Biological Engineering; Güneş, Hande; Bozbağ, Selmi Erim; Erkey, Can; Researcher; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 29633Pt/Al2O3 and bimetallic PtPd/Al2O3 catalysts were prepared via supercritical deposition method using supercritical carbon dioxide. The effects of Pt loading of Pt/Al2O3 and Pd addition to Pt/Al2O3 on particle size, particle size distribution (PSD) and activity for NO and C3H6 oxidation and C3H6-selective catalytic reduction (C3H6-SCR) were investigated. Pt/Al2O3 catalysts were prepared with Pt loadings of 0.6, 1.2 and 2.1 wt% and a bimetallic PtPd/Al2O3 catalyst was prepared with total metal loading of 1.4 wt% and Pt:Pd molar ratio of 1.3:1. A small fraction of the particles agglomerated after calcination at 550 °C. Around 98 % of the particles had an average particle size of ?1 nm. The rest of the particles were larger and average size of these larger particles was ?10 nm for monometallic catalysts and ?6.5 nm for PtPd/Al2O3. All catalysts were found to be active for NO and C3H6 oxidation and C3H6-SCR reactions. NO oxidation performance of 1.2 wt% Pt/Al2O3 catalyst was the highest. C3H6 oxidation activity increased with increasing metal content. Light-off temperature for C3H6 oxidation shifted to higher temperature in the presence of NO, suggesting competitive oxidation of C3H6 and NO. Concentration profiles indicated that C3H6-SCR started when C3H6 conversion by oxidation reached 50 %; C3H6 was consumed both by oxidation and C3H6-SCR at higher conversions.Publication Open Access Outcome of extended right lobe liver transplants(Wiley, 2021) Lozanovski, Vladimir J.; Unterrainer, Christian; Dohler, Bernd; Mehrabi, Arianeb; Süsal, Caner; Other; School of Medicine; Koç University Hospital; 351800Split-liver transplantation offers a solution to the organ shortage problem. However, the outcomes of extended right lobe liver transplantation (ERLT) and whether it is a suitable alternative to full-size liver transplantation (FSLT) remain controversial. We compared the outcomes of ERLT and FSLT in adult recipients of 43,409 first deceased donor liver transplantations using Cox regression. We also analyzed 612 ERLT and 1224 FSLT 1:2 matched cases to identify factors that affect ERLT outcome. The risk of graft loss was significantly higher following ERLT than following FSLT during the first posttransplantation year in the matched and unmatched collective (hazard ratio [HR], 1.39 and 1.27 and P = 0.01 and 0.006, respectively). Every additional hour of cold ischemia time (CIT) increased the risk of 1-year graft loss by 10% in the ERLT group compared with only 3% in the FSLT group (P = 0.003 and <0.001, respectively). Importantly, the outcome of ERLT and FSLT did not differ significantly if the CIT was below 10 hours (HR, 0.71; P = 0.22). One-year graft and patient survival were lower in high-risk ERLT recipients with a Model for End-Stage Liver Disease (MELD) score of ?20 (HR, 1.88; P = 0.03 and HR, 2.03; P = 0.02). In the male recipient–male donor combination, ERLT recipients had a higher risk of 1-year graft loss than FSLT recipients (HR, 2.44; P = 0.006). This was probably because of the significantly higher MELD score in ERLT recipients (P = 0.004). ERLT in adults is an adequate alternative to FSLT and offers an elegant solution to the problem of organ shortage as long as the cold storage is less than 10 hours and the recipient’s MELD score is <20.Publication Open Access Turkey's two elections: the AKP comes back(Johns Hopkins University (JHU) Press, 2016) Öniş, Ziya; Department of International Relations; Faculty Member; Department of International Relations; College of Administrative Sciences and EconomicsIn power since 2002, the Justice and Development Party (AKP) of Recep Tayyip Erdoğan seemed as if it might be losing its hold when Turkish voters went to the polls in June 2015. Yet that “hung election” gave way to another contest in November, and the AKP came roaring back.Publication Open Access Atezolizumab, bevacizumab, and chemotherapy for newly diagnosed stage III or IV ovarian cancer: placebo-controlled randomized phase III trial (IMagyn050/GOG 3015/ENGOT-OV39)(Wolters Kluwer, 2021) Moore, K. N.; Bookman, M.; Sehouli, J.; Miller, A.; Anderson, C.; Scambia, G.; Myers, T.; Robison, K.; Mäenpää, J.; Willmott, L.; Colombo, N.; Thomes-Pepin, J.; Liontos, M.; Gold, M. A.; Garcia, Y.; Sharma, S. K.; Darus, C. J.; Aghajanian, C.; Okamoto, A.; Wu, X.; Safin, R.; Wu, F.; Molinero, L.; Maiya, V.; Khor, V. K.; Lin, Y. G.; Pignata, S.; Taşkıran, Çağatay; Faculty Member; School of Medicine; 134190Purpose: to evaluate the addition of the humanized monoclonal antiprogrammed death ligand-1 (PD-L1) antibody, atezolizumab, to platinum-based chemotherapy and bevacizumab in newly diagnosed stage III or IV ovarian cancer (OC). Methods: this multicenter placebo-controlled double-blind randomized phase III trial (ClinicalTrials.gov identifier: NCT03038100) enrolled patients with newly diagnosed untreated International Federation of Gynecology and Obstetrics (FIGO) stage III or IV OC who either had undergone primary cytoreductive surgery with macroscopic residual disease or were planned to receive neoadjuvant chemotherapy and interval surgery. Patients were stratified by FIGO stage, Eastern Cooperative Oncology Group performance status, tumor immune cell PD-L1 staining, and treatment strategy and randomly assigned 1:1 to receive 3-weekly cycles of atezolizumab 1,200 mg or placebo (day 1, cycles 1-22), with paclitaxel plus carboplatin (day 1, cycles 1-6) plus bevacizumab 15 mg/kg (day 1, cycles 2-22), omitting perioperative bevacizumab in neoadjuvant patients. The co-primary end points were investigator-assessed progression-free survival and overall survival in the intention-to-treat and PD-L1-positive populations. Results: between March 8, 2017, and March 26, 2019, 1,301 patients were enrolled. The median progression-free survival was 19.5 versus 18.4 months with atezolizumab versus placebo, respectively (hazard ratio, 0.92; 95% CI, 0.79 to 1.07; stratified log-rank P = .28), in the intention-to-treat population and 20.8 versus 18.5 months, respectively (hazard ratio, 0.80; 95% CI, 0.65 to 0.99; P = .038), in the PD-L1-positive population. The interim (immature) overall survival results showed no significant benefit from atezolizumab. The most common grade 3 or 4 adverse events were neutropenia (21% with atezolizumab v 21% with placebo), hypertension (18% v 20%, respectively), and anemia (12% v 12%). Conclusion: current evidence does not support the use of immune checkpoint inhibitors in newly diagnosed OC. Insight from this trial should inform further evaluation of immunotherapy in OC.Publication Open Access R-SPONDIN2(+) mesenchymal cells form the bud tip progenitor niche during human lung development(Elsevier, 2022) Hein, Renee F. C.; Wu, Joshua H.; Holloway, Emily M.; Frum, Tristan; Conchola, Ansley S.; Tsai, Yu-Hwai; Wu, Angeline; Fine, Alexis S.; Miller, Alyssa J.; Szenker-Ravi, Emmanuelle; Yan, Kelley S.; Kuo, Calvin J.; Glass, Ian; Frum, Tristan; Glass, Ian; Spence, Jason R.; Reversade, Bruno; Faculty Member; School of MedicineThe human respiratory epithelium is derived from a progenitor cell in the distal buds of the developing lung. These ""bud tip progenitors'' are regulated by reciprocal signaling with surrounding mesenchyme; however, mesenchymal heterogeneity and function in the developing human lung are poorly understood. We interrogated single-cell RNA sequencing data from multiple human lung specimens and identified a mesenchymal cell population present during development that is highly enriched for expression of theWNT agonist RSPO2, and we found that the adjacent bud tip progenitors are enriched for the RSPO2 receptor LGR5. Functional experiments using organoid models, explant cultures, and FACS-isolated RSPO2(+) mesenchyme show that RSPO2 is a critical niche cue that potentiates WNT signaling in bud tip progenitors to support their maintenance and multipotency.Publication Open Access An investigation of time-inconsistency(Informs, 2009) Öncüler, Ayşe; Department of Business Administration; Department of Business Administration; Sayman, Serdar; Faculty Member; Department of Business Administration; College of Administrative Sciences and Economics; 112222Preference between two future outcomes may change over time-a phenomenon labeled as time inconsistency. The term "time inconsistency" is usually used to refer to cases in which a larger-later outcome is preferred over a smaller-sooner one when both are delayed by some time, but then with the passage of time a preference switches to the smaller-sooner outcome. The current paper presents four empirical studies showing that time inconsistency in the other direction is also possible: A person may prefer the smaller-sooner outcome when both options are in the future, but decide to wait for the larger-later one when the smaller option becomes immediately available. We. find that such "reverse time inconsistency" is more likely to be observed when the delays to and between the two outcomes are short (up to a week). We propose that reverse time inconsistency may be associated with a reversed-S shape discount function, and provide evidence that such a discount function captures part of the variation in intertemporal preferences.Publication Open Access Ground-state cooling of mechanical resonatorsby quantum reservoir engineering(Springer Nature, 2021) Department of Physics; Müstecaplıoğlu, Özgür Esat; Naseem, Muhammad Tahir; Faculty Member; Department of Physics; College of Sciences; Graduate School of Sciences and Engineering; 1674; N/ACooling a mechanical oscillator to its ground state underpins many applications ranging from ultra-precise sensing to quantum information processing. The authors propose a new scheme that addresses the problem of the simultaneous cooling of many mechanical resonators with nearby frequencies. Ground-state cooling of multiple mechanical resonators becomes vital to employ them in various applications ranging from ultra-precise sensing to quantum information processing. Here we propose a scheme for simultaneous cooling of multiple degenerate or near-degenerate mechanical resonators to their quantum ground-state, which is otherwise a challenging goal to achieve. As opposed to standard laser cooling schemes where coherence renders the motion of a resonator to its ground-state, we consider an incoherent thermal source to achieve the same aim. The underlying physical mechanism of cooling is explained by investigating a direct connection between the laser sideband cooling and ""cooling by heating"". Our advantageous scheme of cooling enabled by quantum reservoir engineering can be realized in various setups, employing parametric coupling of a cooling agent with the target systems. We also discuss using non-thermal baths to simulate ultra-high temperature thermal baths for cooling.