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See detailLow-bias phosphopeptide enrichment from scarce samples using plastic antibodies
Chen, Jing; Shinde, Sudhirkumar; Koch, Markus-Hermann et al

in Scientific reports (2015), 5

Phosphospecific enrichment techniques and mass spectrometry (MS) are essential tools for comprehending the cellular phosphoproteome. Here, we report a fast and simple approach for low sequence-bias ... [more ▼]

Phosphospecific enrichment techniques and mass spectrometry (MS) are essential tools for comprehending the cellular phosphoproteome. Here, we report a fast and simple approach for low sequence-bias phosphoserine (pS) peptide capture and enrichment that is compatible with low biological or clinical sample input. The approach exploits molecularly imprinted polymers (MIPs, "plastic antibodies") featuring tight neutral binding sites for pS or pY that are capable of cross-reacting with phosphopeptides of protein proteolytic digests. The versatility of the resulting method was demonstrated with small samples of whole-cell lysate from human embryonic kidney (HEK) 293T cells, human neuroblastoma SH-SY5Y cells, mouse brain or human cerebrospinal fluid (CSF). Following pre-fractionation of trypsinized proteins by strong cation exchange (SCX) chromatography, pS-MIP enrichment led to the identification of 924 phosphopeptides in the HEK 293T whole-cell lysate, exceeding the number identified by TiO2-based enrichment (230). Moreover, the phosphopeptides were extracted with low sequence bias and showed no evidence for the characteristic preference of TiO2 for acidic amino acids (aspartic and glutamic acid). Applying the method to human CSF led to the discovery of 47 phosphopeptides belonging to 24 proteins and revealed three previously unknown phosphorylation sites. [less ▲]

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See detailLow-Complexity Estimators for Distributed Sources
Bengtsson, Mats; Ottersten, Björn UL

in IEEE Transactions on Signal Processing (2000), 48(8), 21852194

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See detailLow-density lipoprotein receptor is a calcium/magnesium sensor - role of LR4 and LR5 ion interaction kinetics in low-density lipoprotein release in the endosome.
Martinez-Olivan, Juan; Rozado-Aguirre, Zurine; Arias-Moreno, Xabier et al

in The FEBS journal (2014), 281(11), 2638-58

The low-density lipoprotein receptor (LDLR) captures circulating lipoproteins and delivers them in the endosome for degradation. Its function is essential for cholesterol homeostasis, and mutations in the ... [more ▼]

The low-density lipoprotein receptor (LDLR) captures circulating lipoproteins and delivers them in the endosome for degradation. Its function is essential for cholesterol homeostasis, and mutations in the LDLR are the major cause of familiar hypercholesterolemia. The release of LDL is usually attributed to endosome acidification. As the pH drops, the affinity of the LDLR/LDL complex is reduced, whereas the strength of a self-complex formed between two domains of the receptor (i.e. the LDL binding domain and the beta-propeller domain) increases. However, an alternative model states that, as a consequence of a drop in both pH and Ca2+ concentration, the LDLR binding domain is destabilized in the endosome, which weakens the LDLR/LDL complex, thus liberating the LDL particles. In the present study, we test a key underlying assumption of the second model, namely that the lipoprotein binding repeats of the receptor (specifically repeats 4 and 5, LR4 and LR5) rapidly sense endosomal changes in Ca2+ concentration. Our kinetic and thermodynamic analysis of Ca2+ and Mg2+ binding to LR4 and LR5, as well as to the tandem of the two (LR4-5), shows that both repeats spontaneously release Ca2+ in a time scale much shorter than endosomal delivery of LDL, thus acting as Ca2+ sensors that become unfolded under endosomal conditions. Our analysis additionally explains the lower Ca2+ affinity of repeat LR4, compared to LR5, as arising from a very slow Ca2+ binding reaction in the former, most likely related to the lower conformational stability of apolipoprotein LR4, compared to apolipoprotein LR5, as determined from thermal unfolding experiments and molecular dynamics simulations. [less ▲]

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See detailThe low-dimensional algebraic cohomology of infinite-dimensional Lie algebras of Virasoro-type
Ecker, Jill Marie-Anne UL

Doctoral thesis (2020)

In this doctoral thesis, the low-dimensional algebraic cohomology of infinite-dimensional Lie algebras of Virasoro-type is investigated. The considered Lie algebras include the Witt algebra, the Virasoro ... [more ▼]

In this doctoral thesis, the low-dimensional algebraic cohomology of infinite-dimensional Lie algebras of Virasoro-type is investigated. The considered Lie algebras include the Witt algebra, the Virasoro algebra and the multipoint Krichever-Novikov vector field algebra. We consider algebraic cohomology, meaning we do not put any constraints of continuity on the cochains. The Lie algebras are considered as abstract Lie algebras in the sense that we do not work with particular realizations of the Lie algebras. The results are thus independent of any underlying choice of topology. The thesis is self-contained, as it starts with a technical chapter introducing the definitions, concepts and methods that are used in the thesis. For motivational purposes, some time is spent on the interpretation of the low-dimensional cohomology. First results include the computation of the first and the third algebraic cohomology of the Witt and the Virasoro algebra with values in the trivial and the adjoint module, the second algebraic cohomology being known already. A canonical link between the low-dimensional cohomology of the Witt and the Virasoro algebra is exhibited by using the Hochschild-Serre spectral sequence. More results are given by the computation of the low-dimensional algebraic cohomology of the Witt and the Virasoro algebra with values in general tensor-densities modules. The study consists of a mix between elementary algebra and algorithmic analysis. Finally, some results concerning the low-dimensional algebraic cohomology of the multipoint Krichever-Novikov vector field algebra are derived. The thesis is concluded with an outlook containing possible short-term goals that could be achieved in the near future as well as some long-term goals. [less ▲]

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See detailThe low-dimensional algebraic cohomology of the Witt and the Virasoro algebra with values in natural modules
Ecker, Jill Marie-Anne UL; Schlichenmaier, Martin UL

in Banach Center Publications (2020)

The main aim of this contribution is to compute the low-dimensional algebraic cohomology of the Witt and the Virasoro algebra with values in the adjoint and the trivial module. The last section includes ... [more ▼]

The main aim of this contribution is to compute the low-dimensional algebraic cohomology of the Witt and the Virasoro algebra with values in the adjoint and the trivial module. The last section includes results for the general tensor densities modules, presented without proof. One of our main results is that the third algebraic cohomology of the Witt algebra with values in the adjoint module vanishes, while it is one-dimensional for the Virasoro algebra. The first and the second algebraic cohomology of the Witt and the Virasoro algebra with values in tensor densities modules vanish for almost all modules. In the case they do not vanish, we give explicit expressions for the generating cocycles. In our work, we consider algebraic cohomology and not only the sub-complex of continuous cohomology, meaning we do not put any continuity constraints on the cochains. Consequently, our results are independent of any choice of an underlying topology, and valid for any concrete realizations of the considered Lie algebras. [less ▲]

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See detailThe low-dimensional algebraic cohomology of the Witt and the Virasoro algebra
Ecker, Jill Marie-Anne UL; Schlichenmaier, Martin UL

in Journal of Physics. Conference Series (2018)

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See detailLow-energy Secondary Ion Mass Spectrometry: Investigation of buried interfaces in multi-layer organic thin films
Ngo, Khanh Quyen UL

Doctoral thesis (2012)

Recently, the application of conjugated organic compounds increases significantly in optoelectronic devices. The main performances of these devices such as charge and energy transport, operational ... [more ▼]

Recently, the application of conjugated organic compounds increases significantly in optoelectronic devices. The main performances of these devices such as charge and energy transport, operational lifetime and energy conversion efficiency depend strongly on the doping and the interface structure. Therefore, in this project we develop dynamic SIMS analysis conditions using low energy primary ion beam to analyse multi-layered samples used in organic optoelectronic devices. The objective of this thesis is to study the different artefacts and mechanisms, which may arise in the low-energy depth profiling of organic materials and to optimize the SIMS conditions for interface resolution. For the objectives, in chapter I and II, a general introduction about the organic molecules, the fabrication techniques as well as fundamental aspects of the SIMS technique and the analysis conditions are presented. In chapter III, a study of the fragmentation of different organic films during sub-keV bombardment is performed. The typical secondary ions of different organic molecule are identified and chosen for depth profiling. Chapter IV is a study about air-contact induced topography change on Cs+ sputtered surface. This is useful to avoid artefacts when characterizing the Cs+ sputtered surfaces by AFM or by other techniques. The ability of low-energy SIMS to characterize the metal/organics interfaces is investigated in chapter V and VI. Chapter V is about the SIMS depth resolution and sputter-induced surface roughness studied on a series of metal – organic layered samples. In chapter VI, the diffusion of metal into organic layer seen in SIMS depth profiles is characterized. [less ▲]

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See detailLow-Noise Bulk Unipolar Devices in Si and GaAs
Beneking, H.; Cloos, J.-M.; Fernholz, G. et al

in Proceedings of the 17th European Solid State Devices Research Conference, Bologna, Italy (1987)

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See detailLow-Order Volterra Long-Term Predictors
Despotovic, Vladimir UL; Goertz, Norbert; Peric, Zoran

in Proceedings of the 10. ITG Symposium on Speech Communication (2012, September)

Models based on linear prediction have been used for several decades in different areas of speech signal processing. While the linear approach has led to great advances in the last 40 years, it neglects ... [more ▼]

Models based on linear prediction have been used for several decades in different areas of speech signal processing. While the linear approach has led to great advances in the last 40 years, it neglects nonlinearities present in the speech production mechanism. This paper compares the results of long-term nonlinear prediction based on second-order and third-order Volterra filters. Additional improvement can be obtained using fractionaldelay long-term prediction. Experimental results reveal that the proposed method outperforms linear long-term prediction techniques in terms of prediction gain. [less ▲]

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See detailA Low-Overhead Framework for Inexpensive Embedded Control Systems
Cibrario Bertolotti, Ivan; Hu, Tingting UL; Ghafour Zadeh Kashani, Gilda

in Proc. 12th International Conference on Digital Telecommunications (ICDT2017) (2017)

Embedded control systems are becoming more and more popular, especially in relatively inexpensive consumer prod- ucts, like home appliances and building automation controllers. As a consequence, there is ... [more ▼]

Embedded control systems are becoming more and more popular, especially in relatively inexpensive consumer prod- ucts, like home appliances and building automation controllers. As a consequence, there is an ever increasing desire to reduce firmware development time and cost, without hampering relia- bility and performance. In this paper, a low-overhead firmware development framework is proposed, which allows programmers to develop and deploy typical real-time control software faster than using plain C-language programming. At the same time, experimental results confirm the framework’s efficiency and applicability even to low-end microcontrollers. [less ▲]

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See detailLow-quality leadership in a vertically differentiated duopoly with Cournot competition
Tampieri, Alessandro UL; Lambertini, Luca

in Economics Letters (2012), 115

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See detailLow-quality leadership in a vertically differentiated duopoly with Cournot competition
Lambertini, Luca; Tampieri, Alessandro UL

in Economics Letters (2012), 115

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See detailLow-skilled unemployment, capital-skill complementarity and embodied technical progress
Moreno-Galbis, Eva; Sneessens, Henri UL

in Recherches Economiques de Louvain (2007), 73(3), 330-352

Models developed by recent economic literature do not manage to account simultaneously for the three main stylized facts observed in many EU countries since the mid-seventies: (i) the increase in the ... [more ▼]

Models developed by recent economic literature do not manage to account simultaneously for the three main stylized facts observed in many EU countries since the mid-seventies: (i) the increase in the overall unemployment rate; (ii) the difference between high-skilled and low-skilled unemployment; (iii) the stability of relative wages. This paper focuses on these issues. We construct an intertemporal general equilibrium model seeking to reproduce these facts. We consider two types of jobs and two types of workers. We allow for job competition between high- and low-skilled workers on the low-skilled segment of the labor market and for on-the-job search. Matching processes are represented by matching functions à la Pissarides. Low-skilled search intensities are endogenous and high-skilled workers decide on the amount of effort they devote to search in each labor market segment. Biased technological change is introduced via embodied technical progress and capital-skill complementarity. The model is calibrated and simulated to evaluate the impact of various types of shocks. The model reproduces quite well the unemployment rate changes and the relative wage stability observed over the past two decades [less ▲]

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See detailLow-temperature-grown MBE GaAs for terahertz photomixers
Mikulics, M.; Marso, Michel UL; Fox, A. et al

in EDMO (2001)

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See detailLow-Weight Primes for Lightweight Elliptic Curve Cryptography on 8-bit AVR Processors
Liu, Zhe UL; Groszschädl, Johann UL; Wong, Duncan S.

in Lin, Dongdai; Xu, Shouhuai; Yung, Moti (Eds.) Information Security and Cryptology - 9th International Conference, INSCRYPT 2013, Guangzhou, China, November 27-30, 2013 (2013, November)

Small 8-bit RISC processors and micro-controllers based on the AVR instruction set architecture are widely used in the embedded domain with applications ranging from smartcards over control systems to ... [more ▼]

Small 8-bit RISC processors and micro-controllers based on the AVR instruction set architecture are widely used in the embedded domain with applications ranging from smartcards over control systems to wireless sensor nodes. Many of these applications require asymmetric encryption or authentication, which has spurred a body of research into implementation aspects of Elliptic Curve Cryptography (ECC) on the AVR platform. In this paper, we study the suitability of a special class of finite fields, the so-called Optimal Prime Fields (OPFs), for a "lightweight" implementation of ECC with a view towards high performance and security. An OPF is a finite field Fp defined by a prime of the form p = u*2^k + v, whereby both u and v are "small" (in relation to 2^k) so that they fit into one or two registers of an AVR processor. OPFs have a low Hamming weight, which allows for a very efficient implementation of the modular reduction since only the non-zero words of p need to be processed. We describe a special variant of Montgomery multiplication for OPFs that does not execute any input-dependent conditional statements (e.g. branch instructions) and is, hence, resistant against certain side-channel attacks. When executed on an Atmel ATmega processor, a multiplication in a 160-bit OPF takes just 3237 cycles, which compares favorably with other implementations of 160-bit modular multiplication on an 8-bit processor. We also describe a performance-optimized and a security-optimized implementation of elliptic curve scalar multiplication over OPFs. The former uses a GLV curve and executes in 4.19M cycles (over a 160-bit OPF), while the latter is based on a Montgomery curve and has an execution time of approximately 5.93M cycles. Both results improve the state-of-the-art in lightweight ECC on 8-bit processors. [less ▲]

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See detailA Lower Bound for the Minimum Distance of Intersection Codes
Franck, Christian UL; Sorger, Ulrich UL

in A Lower Bound for the Minimum Distance of Intersection Codes (2010)

Intersection codes are a superclass of Turbo- and LDPC codes. This class contains codes constructed by intersecting interleaved constituent codes. We propose a lower bound for the minimum distance of ... [more ▼]

Intersection codes are a superclass of Turbo- and LDPC codes. This class contains codes constructed by intersecting interleaved constituent codes. We propose a lower bound for the minimum distance of these codes. Using this bound, we compare intersection codes obtained from different constituent codes. [less ▲]

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See detailA lower bound for the volume-averaged mean-square magnetostatic stray field
Michels, Andreas UL; Weissmüller, J.; Birringer, R.

in European Physical Journal B -- Condensed Matter (2002), 29

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See detailLower plasma insulin levels during overnight closed loop in schoolchildren with type 1 diabetes: potential advantage?
Schierloh, Ulrike; Wilinska, M.; Pit-Ten Cate, Ineke UL et al

in PLoS ONE (2019), 14(3: e0212013), 1-11

Background Studies have shown that overnight closed-loop insulin delivery can improve glucose control and reduce the risk of hypoglycemia and hence may improve metabolic outcomes and reduce burden for ... [more ▼]

Background Studies have shown that overnight closed-loop insulin delivery can improve glucose control and reduce the risk of hypoglycemia and hence may improve metabolic outcomes and reduce burden for children with type 1 diabetes and their families. However, research so far has not reported insulin levels while comparing closed-loop to open-loop insulin delivery in children. Therefore, in this study we obtained glucose levels as well plasma insulin levels in children with type 1 diabetes to evaluate the efficacy of a model - based closed-loop algorithm compared to an open-loop administration. Methods Fifteen children with type 1 diabetes, 6-12 years, participated in this open-label single center study. We used a randomized cross over design in which we compared overnight closed-loop insulin delivery with sensor augmented pump therapy for two nights in both the hospital and at home (i.e., 1 night in-patient stay and at home per treatment condition). Only during the in-patient stay, hourly plasma insulin and blood glucose levels were assessed and are reported in this paper. Results Results of paired sample t-tests revealed that although plasma insulin levels were significantly lower during the closed-loop than in the open-loop (Mean difference 36.51 pmol/l; t(13)=2.13, p=.03, effect size d= 0.57), blood glucose levels did not vary between conditions (mean difference 0.76 mmol/l; t(13)=1.24, p=.12, d=0.37). The administered dose of insulin was significantly lower during the closed-loop compared with the open-loop (mean difference 0.10 UI; t(12)=2.45, p=.02, d=0.68). Conclusions Lower insulin doses were delivered in the closed-loop, resulting in lower plasma insulin levels , whereby glucose levels were not affected negatively. This suggests that the closed-loop administration is better targeted and hence could be more effective. [less ▲]

Detailed reference viewed: 73 (1 UL)