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Constant Gaussian curvature foliations and Schläfli formulas of hyperbolic 3-manifolds
http://hdl.handle.net/10993/40694
Title: Constant Gaussian curvature foliations and Schläfli formulas of hyperbolic 3-manifolds
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<br/>Author, co-author: Mazzoli, Filippo
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<br/>Abstract: We study the geometry of the foliation by constant Gaussian curvature surfaces (S_k)_k of a hyperbolic end, and how it relates to the structures of its boundary at infinity and of its pleated boundary. First, we show that the Thurston and the Schwarzian parametrizations are the limits of two families of parametrizations of the space of hyperbolic ends, defined by Labourie in 1992 in terms of the geometry of the leaves S_k. We give a new description of the renormalized volume using the constant curvature foliation. We prove a generalization of McMullen's Kleinian reciprocity theorem, which replaces the role of the Schwarzian parametrization with Labourie's parametrizations. Finally, we describe the constant curvature foliation of a hyperbolic end as the integral curve of a time-dependent Hamiltonian vector field on the cotangent space to Teichmüller space, in analogy to the Moncrief flow for constant mean curvature foliations in Lorenzian space-times.Thermodynamics and Aggregation Kinetics of Lysozyme-Derived Peptides
http://hdl.handle.net/10993/40678
Title: Thermodynamics and Aggregation Kinetics of Lysozyme-Derived Peptides
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<br/>Author, co-author: Hakami Zanjani, Ali Asghar
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<br/>Abstract: When multiple similar protein or peptide chains form non-covalent aggregates, this is termed 'amyloid'. Many serious progressive diseases such as Alzheimer's and Parkinson's are related to undesirable amyloid aggregation. From a positive perspective, functional amyloids have applications as robust and versatile biomaterials in nature, nanotechnology, and biomedicine. To probe the properties of the amyloid aggregation process in terms of the structure of molecules and the microscopic interactions between them, molecular simulation methods such as molecular dynamics (MD) and Monte Carlo (MC) can be used. These tools are especially valuable to illustrate short length and time scales not easily accessible for systems in solution via current experimental techniques. In this work the thermodynamics and aggregation kinetics of the ILQINS hexapeptide are studied. ILQINS is a biological material derived from hen's egg-white lysozyme. Two ILQINS homologues, IFQINS and TFQINS are compared to ILQINS and some of the complex physics which leads to the increased amyloidogenicity of these species, which is not expected from first-order consideration of amino acid properties, is discussed. The IFQINS hexapeptide is of particular interest as the human homologue of ILQINS. Solution X-ray and X-ray crystallography are compared to simulation, verifying that at least two metastable polymorphic structures exist for this system which are substantially different at the atomistic scale, and illustrating the physics driving kinetic competition between polymorphs.Electrophoretic Deposition of WS2 Flakes on Nanoholes Arrays—Role of Used Suspension Medium
http://hdl.handle.net/10993/40639
Title: Electrophoretic Deposition of WS2 Flakes on Nanoholes Arrays—Role of Used Suspension Medium
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<br/>Author, co-author: Mosconi, Dario; Giovannini, Giorgia; Maccaferri, Nicolò; Serri, Michele; Vavassori, Paolo; Agnoli, Stefano; Garoli, Denis
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<br/>Abstract: Here we optimized the electrophoretic deposition process for the fabrication of WS2 plasmonic nanohole integrated structures. We showed how the conditions used for site-selective deposition influenced the properties of the deposited flakes. In particular, we investigated the effect of different suspension buffers used during the deposition both in the efficiency of the process and in the stability of WS2 flakes, which were deposited on an ordered arrays of plasmonic nanostructures. We observed that a proper buffer can significantly facilitate the deposition process, keeping the material stable with respect to oxidation and contamination. Moreover, the integrated plasmonic structures that can be prepared with this process can be applied to enhanced spectroscopies and for the preparation of 2D nanopores.Plasmonic nanopores for single-molecule detection and manipulation: towards sequencing applications
http://hdl.handle.net/10993/40634
Title: Plasmonic nanopores for single-molecule detection and manipulation: towards sequencing applications
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<br/>Author, co-author: Garoli, Denis; Yamazaki, Hirohito; Maccaferri, Nicolò; Wanunu, MeniDistance-based vertex identification in graphs: The outer multiset dimension
http://hdl.handle.net/10993/40570
Title: Distance-based vertex identification in graphs: The outer multiset dimension
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<br/>Author, co-author: Gil-Pons, Reynaldo; Ramirez Cruz, Yunior; Trujillo-Rasua, Rolando; Yero, Ismael G.Effect of grain-boundary diffusion process on the geometry of the grain microstructure of Nd−Fe−B nanocrystalline magnets
http://hdl.handle.net/10993/40567
Title: Effect of grain-boundary diffusion process on the geometry of the grain microstructure of Nd−Fe−B nanocrystalline magnets
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<br/>Author, co-author: Titov, Ivan; Barbieri, Massimiliano; Bender, Philipp Florian; Peral Alonso, Inmaculada; Kohlbrecher, Joachim; Saito, Kotaro; Pipich, Vitaliy; Yano, Masao; Michels, AndreasGalois families of modular forms and application to weight one
http://hdl.handle.net/10993/40541
Title: Galois families of modular forms and application to weight one
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<br/>Author, co-author: Arias-de-Reyna, Sara; Legrand, François; Wiese, Gabor
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<br/>Abstract: We introduce Galois families of modular forms. They are a new kind of family coming from Galois representations of the absolute Galois groups of rational function fields over the rational field. We exhibit some examples and provide an infinite Galois family of non-liftable weight one Katz modular eigenforms over an algebraic closure of F_p for p in {3,5,7,11}.Supraferromagnetic correlations in clusters of magnetic nanoflowers
http://hdl.handle.net/10993/40525
Title: Supraferromagnetic correlations in clusters of magnetic nanoflowers
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<br/>Author, co-author: Bender, Philipp Florian; Honecker, Dirk; Fernández Barquín, Luis
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<br/>Abstract: Magnetic nanoflowers are densely packed aggregates of superferromagnetically coupled iron oxide nanocrystallites, which excel during magnetic hyperthermia experiments. Here, we investigate the nature of the moment coupling within a powder of such nanoflowers using spin-resolved small-angle neutron scattering. Within the powder, the nanoparticles are agglomerated to clusters, and we can show that the moments of neighboring nanoflowers tend to align parallel to each other. Thus, the whole system resembles a hierarchical magnetic nanostructure consisting of three distinct levels, i.e., (i) the ferrimagnetic nanocrystallites as building blocks, (ii) the superferromagnetic nanoflowers, and (iii) the supraferromagnetic clusters of nanoflowers. We surmise that such a supraferromagnetic coupling explains the enhanced magnetic hyperthermia performance in the case of interacting nanoflowers.Size-dependent spatial magnetization profile of Manganese-Zinc ferrite nanoparticles
http://hdl.handle.net/10993/40523
Title: Size-dependent spatial magnetization profile of Manganese-Zinc ferrite nanoparticles
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<br/>Author, co-author: Bersweiler, MathiasSome naturally defined star products for Kaehler manifolds
http://hdl.handle.net/10993/40500
Title: Some naturally defined star products for Kaehler manifolds
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<br/>Author, co-author: Schlichenmaier, MartinPhotoinduced Phase Transitions in Ferroelectrics
http://hdl.handle.net/10993/40484
Title: Photoinduced Phase Transitions in Ferroelectrics
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<br/>Author, co-author: Paillard, Charles; Torun, Engin; Wirtz, Ludger; Iniguez, Jorge; Bellaiche, Laurent
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<br/>Abstract: Ferroic materials naturally exhibit a rich number of functionalities, which often arise from thermally, chemically, or mechanically induced symmetry breakings or phase transitions. Based on density functional calculations, we demonstrate here that light can drive phase transitions as well in ferroelectric materials such as the perovskite oxides lead titanate and barium titanate. Phonon analysis and total energy calculations reveal that the polarization tends to vanish under illumination, to favor the emergence of nonpolar phases, potentially antiferroelectric, and exhibiting a tilt of the oxygen octahedra. Strategies to tailor photoinduced phases based on phonon instabilities in the electronic ground state are also discussed.
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<br/>Commentary: C. P. and L. B. thank the ARO Grant No. W911NF-16-1-0227. We also acknowledge support from the National Research Fund, Luxembourg through Project No. INTER/ANR/13/20/NANOTMD (E. T. and L. W.); Project No. INTER/ANR/16/11562984/EXPAND (J. I.) and the inter-mobility program (Grant No. 15/9890527/GREENOX, J. I. and L. B.). C. P. thanks the AHPCC and a DoD challenge grant for use of computing resources. We thank B. Dkhil and P. Ruello for interesting discussions.Reducibility of n-ary semigroups: from quasitriviality towards idempotency
http://hdl.handle.net/10993/40481
Title: Reducibility of n-ary semigroups: from quasitriviality towards idempotency
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<br/>Author, co-author: Couceiro, Miguel; Devillet, Jimmy; Marichal, Jean-Luc; Mathonet, Pierre
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<br/>Abstract: Let $X$ be a nonempty set. Denote by $\mathcal{F}^n_k$ the class of associative operations $F\colon X^n\to X$ satisfying the condition $F(x_1,\ldots,x_n)\in\{x_1,\ldots,x_n\}$ whenever at least $k$ of the elements $x_1,\ldots,x_n$ are equal to each other. The elements of $\mathcal{F}^n_1$ are said to be quasitrivial and those of $\mathcal{F}^n_n$ are said to be idempotent. We show that $\mathcal{F}^n_1=\cdots =\mathcal{F}^n_{n-2}\varsubsetneq\mathcal{F}^n_{n-1}\varsubsetneq\mathcal{F}^n_n$.
The class $\mathcal{F}^n_1$ was recently characterized by Couceiro and Devillet \cite{CouDev}, who showed that its elements are reducible to binary associative operations. However, some elements of $\mathcal{F}^n_n$ are not reducible. In this paper, we characterize the class $\mathcal{F}^n_{n-1}\setminus\mathcal{F}^n_1$ and show that its elements are reducible. In particular, we show that each of these elements is an extension of an $n$-ary Abelian group operation whose exponent divides $n-1$.Time-Resolved Investigations and Biotechnological Applications of Plasmonic Nanostructures
http://hdl.handle.net/10993/40444
Title: Time-Resolved Investigations and Biotechnological Applications of Plasmonic Nanostructures
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<br/>Author, co-author: Maccaferri, NicolòStandardizing and redefining the analyzing methods of magnetic nanoparticles within the EU project NanoMag
http://hdl.handle.net/10993/40432
Title: Standardizing and redefining the analyzing methods of magnetic nanoparticles within the EU project NanoMag
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<br/>Author, co-author: Bender, Philipp FlorianThiazole- and selenazole-comprising high-affinity inhibitors possess bright microsecond-scale photoluminescence in complex with protein kinase CK2.
http://hdl.handle.net/10993/40429
Title: Thiazole- and selenazole-comprising high-affinity inhibitors possess bright microsecond-scale photoluminescence in complex with protein kinase CK2.
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<br/>Author, co-author: Vahter, Jurgen; Viht, Kaido; Uri, Asko; Manoharan, Ganesh Babu; Enkvist, Erki
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<br/>Abstract: A previously disclosed protein kinase (PK) CK2-selective inhibitor 4-(2-amino-1,3-thiazol-5-yl)benzoic acid (ATB) and its selenium-containing counterpart (ASB) revealed remarkable room temperature phosphorescence when bound to the ATP pocket of the protein kinase CK2. Conjugation of these fragments with a mimic of CK2 substrate peptide resulted in bisubstrate inhibitors with increased affinity towards the kinase. Attachment of the fluorescent acceptor dye 5-TAMRA to the conjugates led to significant enhancement of intensity of long-lifetime (microsecond-scale) photoluminescence of both sulfur- and selenium-containing compounds. The developed photoluminescent probes make possible selective determination of the concentration of CK2 in cell lysates and characterization of CK2 inhibitors by means of time-gated measurement of photoluminescence.
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<br/>Commentary: Copyright (c) 2018 Elsevier Ltd. All rights reserved.Benzoselenadiazole-based responsive long-lifetime photoluminescent probes for protein kinases
http://hdl.handle.net/10993/40427
Title: Benzoselenadiazole-based responsive long-lifetime photoluminescent probes for protein kinases
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<br/>Author, co-author: Ekambaram, Ramesh; Enkvist, Erki; Manoharan, Ganesh Babu; Ugandi, Mihkel; Kasari, Marje; Viht, Kaido; Knapp, Stefan; Issinger, Olaf-Georg; Uri, AskoPIM kinase-responsive microsecond-lifetime photoluminescent probes based on selenium-containing heteroaromatic tricycle
http://hdl.handle.net/10993/40424
Title: PIM kinase-responsive microsecond-lifetime photoluminescent probes based on selenium-containing heteroaromatic tricycle
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<br/>Author, co-author: Ekambaram, Ramesh; Manoharan, Ganesh Babu; Enkvist, Erki; Ligi, Kadri; Knapp, Stefan; Uri, AskoThe Breuer-Major Theorem in total variation: improved rates under minimal regularity
http://hdl.handle.net/10993/40393
Title: The Breuer-Major Theorem in total variation: improved rates under minimal regularity
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<br/>Author, co-author: Nourdin, Ivan; Nualart, David; Peccati, GiovanniSelf-Organizing Cellulose Nanorods: From the fundamental physical chemistry of self-assembly to the preparation of functional films
http://hdl.handle.net/10993/40375
Title: Self-Organizing Cellulose Nanorods: From the fundamental physical chemistry of self-assembly to the preparation of functional films
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<br/>Author, co-author: Honorato Rios, Camila
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<br/>Abstract: Cellulose nanocrystals (CNCs), nanorods isolated by acid hydrolysis from cellulose sources, be-
long to a selective type of functional biomaterials. The intriguing ability of these nanoparticles
to self-organize and develop a chiral nematic liquid crystal phase when suspended in aqueous
suspensions, is increasing interest regardless of the diverse range of research fields. Unfortu-
nately (or fortunately, for this thesis), pristine CNCs are always disperse, with great variations
in rod length within a single sample. Of particular interest is the fractionation of CNC rods by
separation of the coexisting phases: isotropic phase from the liquid crystalline (LC) part. Since
the aspect ratio is considered to be the critical parameter that dictates the particle fraction
at which cholesteric-isotropic phase separation starts, it is expected that the high aspect ratio
rods will separate from low aspect ratio rods, and this is indeed what I found in this thesis.
By a systematic repetition of separation of phases, I could reach a quality of separation of long
from short rods that is remarkable. The fractionation procedure was then improved by varying
the equilibrium phase volume fraction at which the phases were separated, reducing with
this new procedure the multiple separations from five cycles to only one. The onset of liquid
crystallinity was drastically reduced in the long rod fraction and the decrease in the threshold
for complete liquid crystallinity was even stronger.
The mass fraction threshold at which gelation of the CNC suspension is triggered is not at all
affected by the fractionation. Since gelation is a percolation phenomenon, the expectation was
that also the onset of gelation would move to lower mass fractions, but this remained at about
the same value. Together with the shift to lower mass fractions of the cholesteric liquid crystal
phase formation we have thus opened access to a whole new range of the equilibrium phase
diagram, where the full sample is cholesteric yet not gelled.
I demonstrate that the critical parameter for inducing gelation is in fact not the fraction of
CNC, but the concentration of counterions in the solution. This suggests that the gelation is
more complex than direct percolation between individual CNC rods, and instead is related to
loss of colloidal stability due to reduced electrostatic screening.
I also show that the behavior of key parameters, such as the period of the helical modulation,
so-called pitch, that is characteristic of the cholesteric phase, is very different in the range of
phase coexistence compared to the range of complete liquid crystallinity. In addition, I found
that the dependence of the pitch on CNC mass fraction has less to do with the size of the nanorods but rather than with the variation of effective volume fraction as a result of more rods in the suspension or higher counterion concentration. I corroborate this hypothesis by adding different amounts of salt to CNC suspensions of varying mass fraction such that the ion concentration is held constant, thereby tuning the pitch to the same value throughout the suspensions.
In films prepared by drying CNC suspensions, the pitch can go down to a few hundred nanome-
ters, resulting in circularly polarized colorful Bragg re ection of visible light. By working with
the long-rod fraction we can absolutely obtain a highly-ordered monodomain structure that results in uniform color of films, with only one circular polarization re ected, as should be the case.
While the study is carried out on CNCs, the implications go far beyond this particular nanoma-
terial, revealing new challenges and opportunities in general liquid crystal and colloid physics, as
well as in strategic research where fractionation and the drying of initially disperse populations
of nanorods is desirable.Towards a high-resolution drone-based 3D mapping dataset to optimise flood hazard modelling
http://hdl.handle.net/10993/40361
Title: Towards a high-resolution drone-based 3D mapping dataset to optimise flood hazard modelling
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<br/>Author, co-author: Backes, Dietmar; Schumann, Guy; Teferle, Felix Norman; Boehm, Jan
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<br/>Abstract: The occurrence of urban flooding following strong rainfall events may increase as a result of climate change. Urban expansion, ageing infrastructure and an increasing number of impervious surfaces are further exacerbating flooding. To increase resilience and support flood mitigation, bespoke accurate flood modelling and reliable prediction is required. However, flooding in urban areas is most challenging. State-of-the-art flood inundation modelling is still often based on relatively low-resolution 2.5 D bare earth models with 2-5m GSD. Current systems suffer from a lack of precise input data and numerical instabilities and lack of other important data, such as drainage networks. Especially, the quality and resolution of the topographic input data represents a major source of uncertainty in urban flood modelling. A benchmark study is needed that defines the accuracy requirements for highly detailed urban flood modelling and to improve our understanding of important threshold processes and limitations of current methods and 3D mapping data alike.
This paper presents the first steps in establishing a new, innovative multiscale data set suitable to benchmark urban flood modelling. The final data set will consist of high-resolution 3D mapping data acquired from different airborne platforms, focusing on the use of drones (optical and LiDAR). The case study includes residential as well as rural areas in Dudelange/Luxembourg, which have been prone to localized flash flooding following strong rainfall events in recent years. The project also represents a cross-disciplinary collaboration between the geospatial and flood modelling community. In this paper, we introduce the first steps to build up a new benchmark data set together with some initial flood modelling results. More detailed investigations will follow in the next phases of this project.