Glucksman Fellowship Program Student Research Reports

Shourya Ghosh, under the supervision of Edward Altman, does a statistical comparison of credit ratings from Moody’s and Standard & Poor’s to see whether there are any consistent biases between the two rating agencies. Kenneth McDermid, under the direction of Jeffrey Wurgler, investigates the performance of hedge funds and confirms that institutions with fewer assets and more concentrated portfolios outperform the others and that the out-performance is the result of selection ability. Joe Mellet, under the supervision of David Yermack, examines the market’s reaction to 320 special dividend announcements made in October, November, and December of 2012 in response to the looming tax increases and finds significant Cumulative Abnormal Returns (CARs) in the days surrounding the dividend announcement.

Existence of solutions for a higher order non-local equation appearing in crack dynamics

In this paper, we prove the existence of non-negative solutions for a non-local higher order degenerate parabolic equation arising in the modeling of hydraulic fractures. The equation is similar to the well-known thin film equation, but the Laplace operator is replaced by a Dirichlet-to-Neumann operator, corresponding to the square root of the Laplace operator on a bounded domain with Neumann boundary conditions (which can also be defined using the periodic Hilbert transform). In our study, we have to deal with the usual difficulty associated to higher order equations (e.g. lack of maximum principle). However, there are important differences with, for instance, the thin film equation: First, our equation is nonlocal; Also the natural energy estimate is not as good as in the case of the thin film equation, and does not yields, for instance, boundedness and continuity of the solutions (our case is critical in dimension $1$ in that respect)

Long time, large scale limit of the Wigner transform for a system of linear oscillators in one dimension

We consider the long time, large scale behavior of the Wigner transform W_\eps(t,x,k) of the wave function corresponding to a discrete wave equation on a 1-d integer lattice, with a weak multiplicative noise. This model has been introduced in Basile, Bernardin, and Olla to describe a system of interacting linear oscillators with a weak noise that conserves locally the kinetic energy and the momentum. The kinetic limit for the Wigner transform has been shown in Basile, Olla, and Spohn. In the present paper we prove that in the unpinned case there exists $\gamma_0>0$ such that for any $\gamma\in(0,\gamma_0]$ the weak limit of W_\eps(t/\eps^{3/2\gamma},x/\eps^{\gamma},k), as \eps\ll1, satisfies a one dimensional fractional heat equation $\partial_t W(t,x)=-\hat c(-\partial_x^2)^{3/4}W(t,x)$ with $\hat c>0$. In the pinned case an analogous result can be claimed for W_\eps(t/\eps^{2\gamma},x/\eps^{\gamma},k) but the limit satisfies then the usual heat equation

Cyclodextrin-Based Nanostructure Efficiently Delivers siRNA to Glioblastoma Cells Preferentially via Macropinocytosis

© 2020 by the authors.Small interfering ribonucleic acid (siRNA) has the potential to revolutionize therapeutics since it can knockdown very efficiently the target protein. It is starting to be widely used to interfere with cell infection by HIV. However, naked siRNAs are unable to get into the cell, requiring the use of carriers to protect them from degradation and transporting them across the cell membrane. There is no information about which is the most efficient endocytosis route for high siRNA transfection efficiency. One of the most promising carriers to efficiently deliver siRNA are cyclodextrin derivatives. We have used nanocomplexes composed of siRNA and a β-cyclodextrin derivative, AMC6, with a very high transfection efficiency to selectively knockdown clathrin heavy chain, caveolin 1, and p21 Activated Kinase 1 to specifically block clathrin-mediated, caveolin-mediated and macropinocytosis endocytic pathways. The main objective was to identify whether there is a preferential endocytic pathway associated with high siRNA transfection efficiency. We have found that macropinocytosis is the preferential entry pathway for the nanoparticle and its associated siRNA cargo. However, blockade of macropinocytosis does not affect AMC6-mediated transfection efficiency, suggesting that macropinocytosis blockade can be functionally compensated by an increase in clathrin- and caveolin-mediated endocytosis.This research was funded, in part, by contract numbers PID2019-105858RB-I00 (MCI, AEI, FEDER, UE) and RTI2018-097609-B-C21 (MICIU, AEI, FEDER, UE) to C.O.M. and J.M.G.F. and grants from the Spanish Ministerio de Economía y Competitividad (project SAF2017-89288-R from MINECO/AEI/FEDER/UE), from Junta de Comunidades de Castilla-La Mancha (project SBPLY/19/180501/000067), and ISCIII (AC19/00075) and ERANET Euronanomed Program (project NANO4GLIO) to V.C. It also benefited from the framework of COST Action Nano2Clinic (CA17140), supported by COST (European Cooperation in Science and Technology).Publisher’s versio

Glucksman Fellowship Program Student Research Reports

Shourya Ghosh, under the supervision of Edward Altman, does a statistical comparison of credit ratings from Moody’s and Standard & Poor’s to see whether there are any consistent biases between the two rating agencies. Kenneth McDermid, under the direction of Jeffrey Wurgler, investigates the performance of hedge funds and confirms that institutions with fewer assets and more concentrated portfolios outperform the others and that the out-performance is the result of selection ability. Joe Mellet, under the supervision of David Yermack, examines the market’s reaction to 320 special dividend announcements made in October, November, and December of 2012 in response to the looming tax increases and finds significant Cumulative Abnormal Returns (CARs) in the days surrounding the dividend announcement.

Trehalose-based Janus cyclooligosaccharides: the ‘‘Click’’ synthesis and DNA-directed assembly into pH-sensitive transfectious nanoparticles

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.-- et al.The convergent preparation of Janus molecular nanoparticles by thiourea-‘‘clicking’’ of a,a0 -trehalose halves has been implemented; the strategy allows access to macrocyclic derivatives with seggregated cationic and lipophilic domains that in the presence of DNA undergo pH-dependent self-assembly into lamellar superstructures, as established by electrochemical, structural (SAXS), microscopical (TEM) and computational techniques, that mediate transfection in vitro and in vivo.We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).The authors thank MINECO (contract numbers CTQ2012- 30821, SAF2013-44021-R, CTQ2015-64425-C2-1-R and CTQ2015-64425-C2-2-R), the Junta de Andalucía (contract number FQM2012-1467), University Complutense of Madrid (project no. UCMA05-33-010), the Government of Navarra (Department of Innovation and Industry, contract number IIQ14334.RI1), the University of Navarra Foundation (FUN), and the European Regional Development Funds (FEDER and FSE) for financial support.Peer reviewe