ERC FUNDED PROJECTS

Asymmetric cell division is a key mechanism for the generation of cell diversity in eukaryotes. During this process, a polarized mother cell divides into non-equivalent daughters. These may differentially inherit fate determinants, irreparable damages or age determinants. Our aim is to decipher the mechanisms governing the individualization of daughters from each other. In the past ten years, our studies identified several lateral diffusion barriers located in the plasma membrane and the endoplasmic reticulum of budding yeast. These barriers all restrict molecular exchanges between the mother cell and its bud, and thereby compartmentalize the cell already long before its division. They play key roles in the asymmetric segregation of various factors. On one side, they help maintain polarized factors into the bud. Thereby, they reinforce cell polarity and sequester daughter-specific fate determinants into the bud. On the other side they prevent aging factors of the mother from entering the bud. Hence, they play key roles in the rejuvenation of the bud, in the aging of the mother, and in the differentiation of mother and daughter from each other. Recently, we accumulated evidence that some of these barriers are subject to regulation, such as to help modulate the longevity of the mother cell in response to environmental signals. Our data also suggest that barriers help the mother cell keep traces of its life history, thereby contributing to its individuation and adaption to the environment. In this project, we will address the following questions: 1 How are these barriers assembled, functioning, and regulated? 2 What type of differentiation processes are they involved in? 3 Are they conserved in other eukaryotes, and what are their functions outside of budding yeast? These studies will shed light into the principles underlying and linking aging, rejuvenation and differentiation.

2 200 000 €

Start date: 2010-05-01, End date: 2015-04-30

This interdisciplinary proposal has the objective to greatly enhance our understanding of fundamental biomineralization processes involved in the formation of calcium carbonates by marine organisms, such as corals, foraminifera and bivalves, in order to better understand vital effects. This is essential to the application of these carbonates as proxies for global (paleo-) environmental change. The core of the proposal is an experimental capability that I have pioneered during 2008: Dynamic stable isotopic labeling during formation of carbonate skeletons, tests, and shells, combined with NanoSIMS imaging. The NanoSIMS ion microprobe is a state-of-the-art analytical technology that allows precise elemental and isotopic imaging with a spatial resolution of ~100 nanometers. NanoSIMS imaging of the isotopic label(s) in the resulting biocarbonates and in associated cell-structures will be used to uncover cellular-level transport processes, timescales of formation of different biocarbonate components, as well as trace-elemental and isotopic fractionations. This will uncover the origin of vital effects. With this proposal, I establish a new scientific frontier and guarantee European leadership. The technical and scientific developments resulting from this work are broadly applicable and will radically change scientific ideas about marine carbonate biomineralization and compositional vital effects.

2 182 000 €

Start date: 2010-07-01, End date: 2015-06-30

This project is directed towards development of new laser diagnostic techniques and a deepened physical understanding of more established techniques, aiming at new insights in phenomena related to combustion processes. These non-intrusive techniques with high resolution in space and time, will be used for measurements of key parameters, species concentrations and temperatures. The techniques to be used are; Non-linear optical techniques, mainly Polarization spectroscopy, PS. PS will mainly be developed for sensitive detection with high spatial resolution of "new" species in the IR region, e.g. individual hydrocarbons, toxic species as well as alkali metal compounds. Multiplex measurements of these species and temperature will be developed as well as 2D visualization. Quantitative measurements with high precision and accuracy; Laser induced fluorescence and Rayleigh/Raman scattering will be developed for quantitative measurements of species concentration and 2D temperatures. Also a new technique will be developed for single ended experiments based on picosecond LIDAR. Advanced imaging techniques; New high speed (10-100 kHz) visualization techniques as well as 3D and even 4D visualization will be developed. In order to properly visualize dense sprays we will develop Ballistic Imaging as well as a new technique based on structured illumination of the area of interest for suppression of multiple scattering which normally cause blurring effects. All techniques developed above will be used for key studies of phenomena related to various combustion phenomena; turbulent combustion, multiphase conversion processes, e.g. spray combustion and gasification/pyrolysis of solid bio fuels. The techniques will also be applied for development and physical understanding of how combustion could be influenced by plasma/electrical assistance. Finally, the techniques will be prepared for applications in industrial combustion apparatus, e.g. furnaces, gasturbines and IC engines

2 466 000 €

Start date: 2010-02-01, End date: 2015-01-31

Cells use circuits of interacting proteins to respond to their environment. In the past decades, molecular biology has provided detailed knowledge on the proteins in these circuits and their interactions. To fully understand circuit function requires, in addition to molecular knowledge, new concepts that explain how multiple components work together to perform systems level functions. Our lab has been a leader in defining such concepts, based on combined experimental and theoretical study of well characterized circuits in bacteria and human cells. In this proposal we aim to find novel principles on how circuits resist fluctuations and errors, and how they can be controlled by drugs: (1) Why do key regulatory systems use bifunctional enzymes that catalyze antagonistic reactions (e.g. both kinase and phosphatase)? We will test the role of bifunctional enzymes in making circuits robust to variations in protein levels. (2) Why are some genes regulated by a repressor and others by an activator? We will test this in the context of reduction of errors in transcription control. (3) Are there principles that describe how drugs combine to affect protein dynamics in human cells? We will use a novel dynamic proteomics approach developed in our lab to explore how protein dynamics can be controlled by drug combinations. This research will define principles that unite our understanding of seemingly distinct biological systems, and explain their particular design in terms of systems-level functions. This understanding will help form the basis for a future medicine that rationally controls the state of the cell based on a detailed blueprint of their circuit design, and quantitative principles for the effects of drugs on this circuitry.

2 261 440 €

Start date: 2010-03-01, End date: 2015-02-28

Allostery is a fundamental concept Nature uses to regulate the affinity of a certain substrate to an active site of a protein by binding a ligand to a distant allosteric site. We will design experimental tools to gain an atomistic understanding of the conformational transitions that give rise to allostery. We will approach the problem from two distinctively different directions. First, we will initiate conformational transitions of proteins that per se are not photoswitchable, by cross-linking two sites of an allosteric protein with a photo-switchable azobenzene-moiety to initiate a conformational transition similar to ligand binding. We will use ultrafast infrared spectroscopy to time-resolve the conformational transition. Second, we will experimentally verify a frequently expressed hypothesis that allosteric and active site communicate by exchange of vibrational energy. To that end, we will design a versatile approach that allows us to locally deposit vibrational energy at essentially any site in a protein (e.g. through pumping of an optical chromophore that undergoes ultrafast internal conversion), and to detect its appearance at any other site by using vibrational transitions as local thermometers. Thereby, we will map out a network of connectivity in a given protein. Both approaches will applied both to one and the same protein family. One concrete example are PDZ domains, which are among the smallest allosteric proteins, and for which the connection between allostery and vibrational energy flow has been made explicit, based on computer simulations. We will eventually test this hypothesis experimentally, and provide the foundation for a description of allostery that is on an equal footing as our current understanding of protein folding.

2 400 000 €

Start date: 2010-02-01, End date: 2015-07-31

The proposal is to look for, and investigate, new ergodic theoretic types of behavior for dynamical systems which act on non compact spaces. These could include transience and non-trivial ways of escape to infinity, critical phenomena similar to phase transitions, and new types of measure rigidity. There are potential applications to smooth ergodic theory (non-uniform hyperbolicity), algebraic ergodic theory (actions on homogeneous spaces), and probability theory (weakly dependent stochastic processes).

539 479 €

Start date: 2009-10-01, End date: 2014-09-30

The ribosome is a large cellular organelle that plays a central role in the process of protein synthesis in all organisms. Currently, structural information at atomic resolution exists only for bacterial ribosomes and some of their functional complexes. Eukaryotic ribosomes are larger and significantly more complex than their bacterial counterparts. They consist of two unequal subunits with a combined molecular weight of approximately 4 million Daltons and contain 70-80 different protein molecules and four different RNAs. Currently the only structural information on eukaryotic ribosomes is available from cryo electron microscopic reconstructions in the nanometer resolution range, which is insufficient to derive information about the function of the eukaryotic ribosome at the atomic level. The aim of this proposal is to use X-ray crystallography to obtain structural and functional information on the eukaryotic ribosome and its functional complexes at high resolution. The key targets of the structural work will be: i) the structure of the small ribosomal subunit, ii) the structure of the large ribosomal subunit, and iii) structures of complexes involved in the initiation of protein synthesis. Besides the obvious fundamental importance of this research for understanding protein synthesis in eukaryotes the proposed studies will also be the prerequisite for understanding the structural basis of the regulation of protein synthesis in normal cells and how it is perturbed in various diseases. Finally, comparing the structures of bacterial and eukaryotic ribosomes is important for understanding the specificity of various clinically used antibiotics for the bacterial ribosome.

2 446 725 €

Start date: 2010-07-01, End date: 2015-06-30

The general framework is that of game theory, with multiple participants ( players ) that interact repeatedly over time. The players may be people, corporations, nations, computers even genes. While many of the standard concepts of game theory are static by their very nature (for example, strategic equilibria and cooperative solutions), it is of utmost importance theoretically as well as in applications to study dynamic processes, and relate them to appropriate static solutions. This is a fundamental issue. On the one hand, the significance of a solution depends in particular on how easy it is to reach it. On the other hand, natural dynamics, that is, processes that to a certain degree reflect observed behaviors and actual institutions, are important to study and understand in their own right. We propose to work on three main areas. First, adaptive dynamics: the goal is to characterize those classes of dynamics for which convergence to Nash or correlated equilibria can be obtained, and those for which it cannot, and to find and study natural dynamics that are related to actual behavior and yield useful insights. Second, evolutionary dynamics: the goal is to investigate evolutionary and similar dynamics, with a particular emphasis on understanding the role that large populations may play, and on characterizing which equilibria are evolutionarily stable and which are not. Third, bargaining and cooperation: the goal is to develop a general research program that studies natural bargaining procedures that lead to cooperation and are based directly on the strategic form; some particular aims are to establish connections between the bargaining institutions and the resulting cooperative solutions, and to analyze relevant economic models.

1 361 000 €

Start date: 2010-01-01, End date: 2015-12-31

Comparative genomics revealed that ~5% of the human genome is conserved among mammals. This fraction is likely functional, and could harbor pathogenic mutations. We have shown (Nature 2002, Science 2003) that more than half of the constrained fraction of the genome consists of Conserved Non-Coding sequences (CNCs). Model organisms provided evidence for enhancer activity for a fraction of CNCs; in addition another fraction is part of large non-coding RNAs (lincRNA). However, the function of the majority of CNCs is unknown. Importantly, a few pathogenic mutations in CNCs have been associated with genetic disorders. We propose to i) perform functional analysis of CNCs, and ii) identify the spectrum of pathogenic CNC mutations in recognizable human phenotypes. The aims are: 1. Functional genomic connectivity of CNCs 1a. Use 4C in CNCs in various cell types and determine their physical genomic interactions. 1b. Perform targeted disruption of CNCs in cells and assess the functional outcomes. 2. Pathogenic variation of CNCs 2a. Assess the common variation in CNCs: i) common deletion/insertions in 350 samples by aCGH of all human CNCs; ii) common SNP/small indels using DNA selection and High Throughput Sequencing (HTS) of CNCs in 100 samples. 2b. Identify likely pathogenic mutations in developmental syndromes. Search for i) large deletions and duplications of CNCs using aCGH in 1500 samples with malformation syndromes, 1000 from spontaneous abortions, and 500 with X-linked mental retardation; and ii) point mutations in these samples by targeted HTS. The distinction between pathogenic and non-pathogenic variants is difficult, and we propose approaches to meet the challenge. 3. Genetic control (cis and trans eQTLs) of expression variation of CNC lincRNAs, using 200 samples.

2 353 920 €

Start date: 2010-07-01, End date: 2015-06-30

One of the key challenges in scientific research is to link together our understanding of different levels of biological organisation. This challenge is fundamental to the scientific endeavour: from understand how genes interact to drive the cell, to how cells interact to form organisms, up to how organisms interact to form groups and societies. My own and the research of others has addressed this question in the context of the collective behaviour of animals. Mathematical models of complex systems have been used to successfully predict experimental outcome. Most previous studies are however limited in one important aspect: individuals are treated as identical units. The aim of the proposed research proposed is to investigate features which produce differences within the units. The model systems of our study will be sticklebacks, homing pigeons and house sparrows. Individuals can differ from each other on a range of time scales, from information acquired within the last few minutes, through socially learnt information, to genetically inherited differences. Through a series of experiments on each of the study species, the development of mathematical models which incorporate between individual differences, and novel forms of data analysis, we will begin to understand the role played by individual differences within groups. We will look at the rules of motion for fish and birds; the role of personality in decision-making and how short term information differences improve decision-making accuracy. Achieving the project objectives will greatly enhance our understanding of the relationship between individual animals and the groups they live in, as well as impacting on our understanding of individual differences in other areas of biology.

977 768 €

Start date: 2010-02-01, End date: 2015-01-31

The aim of this project is to try to understand the complex molecular mechanisms involved in DNA editing, repair and recombination during immunoglobulin class switch recombination (CSR) and somatic hypermutation (SHM). We have developed a series of PCR-based assays to study in vivo generated CSR junctions and the pattern of mutations introduced in the immunoglobulin variable region genes in human B cells, allowing us to characterize CSR and SHM in patients with immunodeficiency due to defect(s) in DNA repair/recombination. Novel in vitro CSR assays, based on GFP expression, allowing quantitative measurement of substrate recombination, are also being developed. In addition, we have initiated an evolutionary analysis of the function and structure of activation-induced deaminase, an essential molecule involved both in CSR and SHM, aiming to identify CSR specific-cofactor(s). Combining these approaches, we will be able to define the DNA repair pathways involved in CSR and SHM. The suggested project requires access to patients with various defects in the DNA repair pathways. Many of these diseases are exceedingly rare. However, through worldwide collaboration, we have obtained samples from a majority of the diagnosed patients. We are also refining the existing screening methods and developing novel methods, that will allow identification of additional patients both with recognized and new diseases caused by mutations in DNA repair pathways. Finally, we hope to be able to address the question whether illegitimate CSR events are associated with predisposition to lymphomagenesis in patients with immunodeficiency/DNA repair defect(s), by analyzing the CSR induced chromosomal breaks and translocations in these patients. A large-scale sequencing project is also planned to characterize the CSRnome in B-cell lymphoma samples.

1 888 166 €

Start date: 2009-12-01, End date: 2014-11-30

Metabolic engineering is the development of new cell factories or improving existing ones, and it is the enabling science that allows for sustainable production of fuels and chemicals through biotechnology. With the development in genomics and functional genomics, it has become interesting to evaluate how advanced high-throughput experimental techniques (transcriptome, proteome, metabolome and fluxome) can be applied for improving the process of metabolic engineering. These techniques have mainly found applications in life sciences and studies of human health, and it is necessary to develop novel bioinformatics techniques and modelling concepts before they can provide physiological information that can be used to guide metabolic engineering strategies. In particular it is challenging how these techniques can be used to advance the use of mathematical modelling for description of the operation of complex metabolic networks. The availability of robust mathematical models will allow a wider use of mathematical models to drive metabolic engineering, in analogy with other fields of engineering where mathematical modelling is central in the design phase. In this project the advancement of novel concepts, models and technologies for enhancing metabolic engineering will be done in connection with the development of novel cell factories for high-level production of different classes of products. The chemicals considered will involve both commodity type chemicals like 3-hydroxypropionic acid and malic acid, that can be used for sustainable production of polymers, an industrial enzyme and pharmaceutical proteins like human insulin.

2 499 590 €

Start date: 2010-01-01, End date: 2014-12-31

The detection of DNA hybridization and protein recoginittion event (immunoassay) is very important for the diagnosis and treatment of genetic diseases, for the detection infectious agents and for reliable forensic analysis. Recent activity has focused on the development of hybridization assays that permit simultaneous determination of multiple DNA or protein targets, using optical or electrochemical coding technology, based on unique encoding properties of semiconductor crystal nanoparticle tags (quantum dots). Described multi-target bio assays were performed in batch mode, involving significant amount of steps, connected with the possibility of human error, time and reagents consuming. Lab-on-a-chip technology offers tremendous potential for obtaining desired analytical information in a simpler, faster and cheaper way compared to traditional batch/laboratory-based technology. Particularly attractive for multiple DNA and protein recognition applications (i.e. point-of-care) is the high-throughput, automation, versatility, portability, reagent/sample economy and high-performance of such micromachined devices. Overall objective of the proposed research is to create and characterize a portable microanalyzer, based on a novel advanced Lab-on-a-Chip technology with magnetic separation and end-column quantum dots tracers voltammetric detection of multiple DNA and protein targets for point-of-care , automated, high-throughput, sensitive, selective and simultaneous assays. The new micro-total analytical system will rely on coupling of microfluidic transport of samples, effective flow-through magnetic separation complementary/non-complementary DNA and protein targets and a novel chip-based voltammetric stripping detection of quantum dot tags. To successfully complete such advanced micro-total analytical system, several fundamental and practical issues will be addressed.

1 400 000 €

Start date: 2010-04-01, End date: 2015-03-31

Data mining provides large benefits to the commercial, government and homeland security sectors, but the aggregation and storage of huge amounts of data about citizens inevitably leads to erosion of privacy. To achieve the benefits that data mining has to offer, while at the same time enhancing privacy, we need technological solutions that simultaneously enable data mining while preserving privacy. The current state of the art has focused on providing privacy-preserving solutions for very specific problems, and has thus taken a local perspective. Although this is an important first step in the development of privacy-preserving solutions, it is time for a global perspective on the problem that aims for providing full integrated solutions. Our goal in this research is to study privacy and develop comprehensive solutions for enhancing it in the digital era. Our proposed research project includes foundational research on privacy, an infrastructure level for achieving anonymity over the Internet, key cryptographic tools for constructing privacy-preserving protocols, and development of large-scale applications that are built on top of all of the above. The novelty of our research is in our focus on fundamental issues towards comprehensive solutions that are aimed for large-scale data sources. The project s outcome will allow migration from local solutions for specific problems that are suited for small to medium scale data sources to comprehensive privacy-preserving database and data mining solutions for large scale data warehouses. Achieving this great challenge carries immense scientific, technological and societal rewards.

1 921 316 €

Start date: 2009-10-01, End date: 2014-09-30

The general theme is to explore the connections between reasoning and computations in mathematics. There are two main research directions. The first research direction is a refomulation of Hilbert's program, using ideas from formal, or pointfree topology. We have shown, with multiple examples, that this allows a partial realization of this program in commutative algebra, and a new way to formulate constructive mathematics. The second research direction explores the computational content using type theory and the Curry-Howard correspondence between proofs and programs. Type theory allows us to represent constructive mathematics in a formal way, and provides key insight for the design of proof systems helping in the analysis of the logical structure of mathematical proofs. The interest of this program is well illustrated by the recent work of G. Gonthier on the formalization of the 4 color theorem.

1 912 288 €

Start date: 2010-04-01, End date: 2015-03-31

Research will focus on the generation of electric power by mesoscopic solar cells, a domain where the PI has an outstanding track record and leadership on the global scale. The target is to increase the photovoltaic conversion efficiency from currently 11 to over 15 percent rendering these new solar cells very attractive for applications in large areas of photovoltaic electricity production. The approach to reach this challenging target is highly creative and has a strongly interdisciplinary character. Successful implementation of the project goals is assured by the vast experience and know how of the PI and his team in the key areas of the project. The project is divided in four work packages. The first three introduce creative new concepts to enhance substantially the performance of single-junction dye sensitized nanocrystalline devices, while the fourth addresses multi-junction cells and photon up-conversion systems. The tasks to be accomplished comprise 1) The theoretically assisted conception and synthesis of new molecular sensitizers to extend the spectral response of dye sensitized photovoltaic cells into the near IR up to 900 nm, increasing substantially the short circuit photocurrent of the solar cell. 2) The implementation of highly innovative mesoscopic oxides structures to support the molecular dye or quantum dot and collect the photo-generated charge carriers. 3) The introduction of smart amphiphilic molecular insulators and ultra-thin ceramic barriers at the mesoscopic junction in order to retard the interfacial electron-hole recombination and 4) The exploration of radically new cell embodiments based on multi-junction tandem cells and photon up-conversion schemes, whose solar to electric power conversion efficiency can be raised beyond the Shockley-Queiser limit of 32 percent.

2 046 000 €

Start date: 2010-03-01, End date: 2015-02-28

We describe here an innovative strategy for understanding the so-called magnetostrophic regime of fluid flow in the Earth s core, and thus the mechanisms by which the Earth s magnetic field is sustained over time. The magnetostrophic regime is the state in which Lorentz (magnetic) forces are balanced by Coriolis (rotational) forces and pressure gradients and is thought to be the zeroth order force balance in the core. We propose a series of ground-breaking experiments using liquid sodium contained in a rapidly rotating sphere containing a differentially rotating solid inner sphere. For the first time electric current is injected into the fluid in different configurations in order that the Lorentz force is everywhere significant. Various other magnetic fields can be applied from the exterior and the interior. The influence of turbulence, viscous and magnetic boundary layers will be examined. The presence of instabilities and wave motion will be studied, and the existence of steady solutions will be naturally determined. Diagnostic measurements of magnetic fields and electrical potentials, and Doppler velocimetry will characterise the experiment. These unique experiments are backed by numerical calculations. Complementary studies will analyse the observed magnetic field over the last 400 years in the same magnetostrophic framework. An inverse method will be developed to find the initial state of the field that evolves in a manner compatible with observations. This will elucidate the interior structure of the magnetic field for the first time, determining the amplitude and morphology of the field. The importance of magnetic diffusion (Joule heating) will arise naturally, and fluid motion in the entire core will be found, allowing comparison with geodetic observations.

3 116 900 €

Start date: 2010-05-01, End date: 2016-04-30

Emulsions consist of one liquid dispersed as nanoscopic droplets in another liquid, such as milk, and butter. The understanding of the structure and stability of emulsions is commonly obtained from empirical studies in which a macroscopic parameter (like temperature or concentration of constituents) is varied. Since the work of Irving Langmuir and others (published in 1917) it is well established that the stability and properties of these nanoscopic droplets are strongly influenced by the state of the droplet interface. However, despite the abundance and importance of emulsions in our daily lives, the molecular mechanisms that dictate the stability and properties of emulsions are still unknown. This lack of insight is caused by the system itself: the condensed surrounding medium forms an impenetrable barrier to most molecular probes. Nonlinear light scattering spectroscopy, a novel method I have developed (both theoretically and experimentally), offers a way of obtaining molecular information (chemical composition, molecular orientation, ordering and chirality) of the interfaces of nanoscopic particles in solution. With this method it should be possible to observe, in-situ, non-invasively and label-free, the molecules at the interface of the nanoscopic droplets in solution. I therefore propose to form a small group that investigates interfaces of nanoscopic droplets in emulsions on the molecular level and timescale. Using femtosecond nonlinear light scattering methods we can finally observe the molecules that dictate the structure and stability of emulsions in action.

1 150 000 €

Start date: 2009-11-01, End date: 2014-10-31

MicroRNAs (miRNAs) are a novel class of genes, accounting for >1% of genes in a typical animal genome. They constitute an important layer of gene regulation that affects diverse processes such as cell differentiation, apoptosis, and metabolism. Despite such critical roles, deciphering the mechanism of action of miRNAs has been difficult, leading to multiple, partially contradictory, models of miRNA activity. Moreover, adding an additional layer of complexity, it is now emerging that miRNA activity is regulated by various mechanisms that we are only beginning to identify. Our objective is to understand how miRNAs are regulated under physiological conditions, in the roundworm Caenorhabditis elegans. We will focus on pathways of miRNA turnover, an issue of fundamental importance that has received little attention because miRNAs are widely held to be highly stable molecules. However, miRNA over-accumulation causes aberrant development and disease, prompting us to test rigorously whether degradation can antagonize miRNA activity and either identify the machinery involved, or confirm the dominance of other regulatory modalities, whose components we will identify. C. elegans is the organism in which miRNAs and many components of the miRNA machinery were discovered. However, previous studies emphasized genetics and cell biology approaches, limiting the degree of mechanistic insight that could be obtained. In addition to exploiting the traditional strengths of C. elegans, we will therefore develop and apply biochemical and genomic techniques to obtain a comprehensive understanding of miRNA regulation, enabling us to demonstrate both molecular mechanisms and physiological relevance. Given the importance of miRNAs in development and disease, identifying the regulators of these tiny gene regulators will be both of scientific interest and biomedical relevance.

1 782 200 €

Start date: 2010-05-01, End date: 2015-04-30

Nanosystems are integrated systems exploiting nanoelectronic devices. In particular, this proposal considers silicon nanowire and carbon nanotube technologies as replacement/enhancement of current silicon technologies. This proposal addresses high-risk, high-reward research, unique in its kind. The broad objective of this proposal is to study system organization, architectures and design tools which, based on a deep understanding and abstraction of the manufacturing technologies, allow us to realize nanosystems that outperform current integrated systems in terms of capabilities and performance. Thus this proposal will address modelling of technological aspects, synthesis and optimization of information processing functions from high-level specifications into the nanofabric, and new design technologies for specific aspects of nanosystems including, but not limited to, sensing and interfacing with the environment. This proposal will address also cross-cutting design goals such as ultra-low power and high-dependability design, with the overall objective of realizing nanosystems that are autonomous (w.r. to energy consumption) and autonomic (i.e., self healing). The scientific novelty of this proposal stems from the use of a nanofabric, where computation, sensing and communication are supported by a homogeneous means as well as from the study of algorithmic tools for mapping high-level functions onto the nanofabric. The intrinsic benefit of this research is to provide a design flow that extends both the technological basis and the capabilities of integrated systems, thus strengthening the industrial European position in a key sector where disruptive innovation is key for survival. The extrinsic benefit of this research is to broaden the use of nanosystems to new domains, including mobile/distributed embedded systems, health/environment management, and other areas that are critical to our lives.

2 499 594 €

Start date: 2010-04-01, End date: 2015-12-31

There is an immediate need to increase our understanding of the genetic basis for fitness differences in natural populations (Ellegren and Sheldon Nature 452:169-175, 2008). Fortunately, technological developments within genome research, notably the recent ability to retrieve massive amounts of DNA sequence data based on next generation sequencing , will make possible completely novel investigations of the link between genotypes and phenotypes in non-model organisms. With our background as major players in molecular ecology and evolutionary genomics of non-models for the last 15-20 years, we are excellently placed to take on a leading role in this process, developing a Next Generation Molecular Ecology . This research program will combine studies of candidate genes with large-scale gene expression analysis, several mapping approaches and comparative genomics to study the genetic basis of trait evolution in wild bird populations. First, we will search for and analyse loci involved with reproductive isolation and adaptive population divergence in a well-known system for speciation research the pied flycatcher and the collared flycatcher. A milestone of this program will be genome sequencing of the two flycatcher species. Second, we will track the genetic basis of behaviour using a unique breeding population of zebra finches and benefitting from the recently obtained genome sequence of this species. Third, we will identify the targets for adaptive evolution during avian evolution using comparative genomics. Overall, the program will be able to reveal the molecular genetic architecture behind phenotypic variation. The potential for scientific break-through in this interdisciplinary program should be significant.

2 500 000 €

Start date: 2010-04-01, End date: 2015-09-30

To understand the molecular basis of any biological process, it is critical that one is not only able to visualize and monitor molecular events that underlie this process, but also to possess the tools to manipulate these events in a spatial and temporal fashion both in and out of the cell. The overall objective of this proposal is to apply chemical biology approaches to allow real time monitoring of protein aggregation and to dissect the role of specific disease-associated post-translational modifications, phosphorylation, nitration, and truncation on the structure, aggregation, and biochemical properties of monomeric a-syn in health and disease. To achieve these goals, we plan to use a combination of organic chemistry, molecular biology, proteomics, protein engineering, and semisynthetic strategies to facilitate site-specific introduction of post-translational modifications that can be masked and activated in a controllable manner, both inside and outside living cells. Modified synthetic ±-syn will be introduced into primary neurons and cellular models of synucleinopathies and the consequences of masking or activating specific modifications will be assessed using biochemical, immunofluorescence, and live imaging techniques (Specific Aim 1). The absence of specific molecular probes that allow in vivo monitoring and quantitative measurement of toxic misfolded and aggregation intermediates represents a major impediment to understanding the relationship among protein misfolding, post-translational modification, protein aggregation, neurodegeneration, and cell death in PD and other neurodegenerative disorders. To address this challenge, we plan to develop and characterize novel antibodies that target different species along the amyloid formation pathway of ±-syn (Specific Aim 2).

1 495 400 €

Start date: 2009-12-01, End date: 2014-11-30

"Atom-economic, atom-economic (""click""-type)transformations of donor (N,N-dialkylaniline, TTF, ferrocene)-activated acetylenes with strong electron-accepting olefins (TCNE, TCNQ, tricyanovinyl derivatives) are applied to the construction of stable molecular and supramolecular chromophores with unusual electronic and optical properties. Their properties are characterized in interdisciplinary collaboration with the objectives to provide new classes of chromophores for opto-electronic device applications, to investigate pi-electron delocalization in acetylenic molecular architectures extending into one, two, and three dimensions, and to advance fundamental knowledge in an interplay between experiment and theory allowing prediction and tuning of opto-electronic properties. Specific aims are: 1. New "super-electron acceptors" and investigation of their intra- and intermolecular charge-transfer interactions. These non-planar, stable, and sublimable chromophores are expected to possess high third-order optical nonlinearities and are investigated for formation of amorphous, high-optical quality films and conductive or magnetic charge-transfer complexes and salts with various electron donors. 2. Optically pure alleno-acetylenic macrocycles and oligomers adopting helical conformations. The chiroptical properties of these chromophores are exceptional and will be further enhanced in supramolecular assemblies. 3. Covalently modified fullerenes with increased electron uptake capability for applications in photovoltaic devices. 4. Regular [AB]-type oligomers and polymers using the formation of charge-transfer chromophores from acetylenic precursors as the chain-propagation step. 5. Zwitterionic, redox-amphiphilic dendrimers for mono- and multi-layer formation in organic electronic devices."

1 690 200 €

Start date: 2010-03-01, End date: 2015-02-28

Oxidation reactions are of fundamental importance in Nature and are key transformation in organic synthesis. There is currently a need from society to replace waste-producing expensive oxidants by environmentally benign oxidants in industrial oxidation reactions. The aim with the proposed research is to develop novel green oxidation methodology that also involves hydrogen transfer reactions. In the oxidation reactions the goal is to use molecular oxygen (air) or hydrogen peroxide as the oxidants. In the present project new catalytic oxidations via low-energy electron transfer will be developed. The catalytic reactions obtained can be used for racemization of alcohols and amines and for oxygen- and hydrogen peroxide-driven oxidations of various substrates. Examples of some reactions that will be studied are oxidative palladium-catalyzed C-C bond formation and metal-catalyzed C-H oxidation including dehydrogenation reactions with iron and ruthenium. Coupled catalytic systems where electron transfer mediators (ETMs) facilitate electron transfer from the reduced catalyst to molecular oxygen (hydrogen peroxide) will be studied. Highly efficient reoxidation systems will be designed by covalently linking two electron transfer mediators (ETMs). The intramolecular electron transfer in these hybrid ETM catalysts will significantly increase the rate of oxidation reactions. The research will lead to development of more efficient reoxidation systems based on molecular oxygen and hydrogen peroxide, as well as more versatile racemization catalysts for alcohols and amines.

1 722 000 €

Start date: 2010-01-01, End date: 2015-12-31

Cellular responses to external signals begin at the plasma membrane, where the dynamic assembly of receptors can regulate cellular activity. Membrane-enveloped viruses, including the human immunodeficiency virus (HIV) also assemble at the plasma membrane, exploiting mechanisms evolved for cellular trafficking. However, our physical paradigm for how proteins form mesoscale assemblies is far from complete. While the organization and dynamics of membrane proteins are heterogeneous, commonly used fluorescence-based measurements lack information at the molecular scale. In contrast, single molecule measurements limited to looking at only a few molecules in a given cell lack ensemble information. Thus, the study of protein assembly has been limited by a lack of spatially resolved, dynamic information on ensembles of molecules. We will use super-resolution fluorescence imaging techniques combined with live cell imaging and single molecule tracking to determine how the dynamics of protein assembly are coordinated. The long-term goal of my research is to use quantitative fluorescence methods to identify the physical mechanisms for protein transport and organization in cells. The objective of this proposal is to establish quantitative models of protein assembly in two specific biological systems which were selected for the distinct characteristics of their assembly, and their relevance to human health. This will test the central hypothesis that molecular assembly is enhanced by the organization of the plasma membrane in the form of cytoskeletal elements and protein-lipid platforms. This interdisciplinary research will provide an experimental foundation for a statistical description of the cell, whose behaviour is embedded in protein organization and dynamics.

1 542 518 €

Start date: 2009-12-01, End date: 2015-11-30

I shall pursue two projects both of which belong to the fields of partial differential equations, geometric analysis and mathematical physics. The first project, ``the shock development problem", belongs also to the field of fluid dynamics and aims at a full understanding of how, in the real world of 3 spatial dimensions, hydrodynamic shocks evolve, my previous work having analyzed in detail how they form. The second project, ``the formation of electromagnetic shocks in nonlinear media" aims at establishing how electromagnetic shocks form by the focusing of incoming electromagnetic wave pulses in a nonlinear medium. The case of an isotropic nonlinear dielectric will be studied first, to be followed by the case of a general isotropic medium. The methods of geometric analysis introduced in my previous work shall be employed, in particular the ``short pulse method" introduced in my work on the formation of black holes by the focusing of incoming gravitational waves in general relativity. The application of these methods to the problem for a general isotropic medium will require the development of new geometric structures. My three Ph. D. students shall purse the following three projects, belonging also to the fields of partial differential equations, geometric analysis and mathematical physics. The first project is in nonlinear elasticity. It is the study of the equilibrium configurations, in free space, of a crystalline solid in which a continuous distribution of dislocations is present, and aims at analyzing the relationship between the dislocation distribution and the resulting internal stress field. The second is in general relativity and aims at a theoretical understanding of the phenomena discovered by M. Choptuik in his numerical study of the gravitational collapse of a self-gravitating scalar field in spherical symmetry. The third is the study of hydrodynamic shock interactions and focusing in spherical symmetry.

1 278 000 €

Start date: 2010-03-01, End date: 2015-02-28

Oligomers are toxic in an array of protein misfolding and aggregation (PMA) disorders. However, the chain of events from protein aggregation to dysfunction is poorly understood. Prion diseases are marked by accumulation of PrPSc, a misfolded variant of wild-type PrPC. PrPC mediates PrPSc neurotoxicity and counteracts toxic PrPC mutants, indicating that a subversion of normal PrPC function may underlie neurodegeneration, and this may not be limited to prion disease. Here, we propose to explore these newly discovered physiological functions of PrPC in three paradigms. We show that PrPC assembles into a multiprotein complex containing a protease; neurotoxic PrPC mutants generate a smaller complex that is uncleaved. We show that neuronal expression of PrPC is required in trans for long-term myelin maintenance in peripheral nerves. We will therefore investigate the hypothesis that a fragment of PrPC transmits signals crucial for axomyelinic integrity. We show that PrPC physically interacts with both amyloid b and islet amyloid polypeptide and attenuates functional impairment mediated by these peptides. We therefore propose to test whether subversion of normal PrPC function is involved in diverse PMA disorders. We developed an ex vivo model that accurately reproduces major features of prion infections, most notably neurodegeneration. We have identified several unexpected PrPSc-induced cellular stress pathways which may be common to other PMA disorders. Using this model system, we will clarify the role of PrPC in cell survival pathways and determine the requirement for PrPC in the pathology of other PMA disorders. This proposal capitalizes on provocative recent results and, if successful, will provide valuable insights into PMA toxicity that will go far beyond prion diseases.

2 500 000 €

Start date: 2010-05-01, End date: 2015-04-30

Atomistic computer simulation has established itself as one of the most important methodologies in modern science, its impact being felt in areas as diverse as physics, chemistry, geophysics, materials science and biophysics, to name but a few. Yet in spite of great progress in computer power and algorithms, we are still not able to simulate such important phenomena as nucleation, phase transitions or protein folding. The purpose of this proposal is to strongly push back the limits of length, time scale and accuracy of present-day methods, greatly enhancing the scope of atomistic simulations. We expect the impact of a successful outcome of this proposal to revolutionize the field. We shall make use of three technical innovations: an extension of Langevin-type equations to include correlated (colored) noise; the use of h-matrices to speed up electronic structure calculations; and an intelligent use of neural networks. Our strategy will be complex. We plan to speed up ab-initio molecular dynamics calculations considerably and also to generate new and highly accurate effective potentials based on electronic structure calculations. A large part of our effort will be devoted to the time scale problem. In this respect we shall improve metadynamics so that its implementation becomes as general and as automatic as possible, and we shall also introduce methods for reconstructing the real dynamics from metadynamics. Finally, highly innovative and powerful sampling methods based on specially designed colored noise Langevin equations will be developed.

2 499 600 €

Start date: 2010-08-01, End date: 2015-07-31

Reconstruction of methane flux from lakes: development and application of a new approach

1 554 000 €

Start date: 2009-12-01, End date: 2014-11-30

The general theme of this research proposal involves random walks and percolation theory. The research proposal aims at exploring in depth the surprising links between on the one hand a class of problems directly pertaining to random walks (in particular related to disconnection, or the creation of large vacant components and separating interfaces), and on the other hand questions pertaining to a non-conventional model of percolation based on random interlacements. Traditional methods of percolation typically do not apply to this model. The present research program if successfull ought to uncover new paradigms and lead to the development of new methods.

583 092 €

Start date: 2010-04-01, End date: 2014-03-31

We aim to study transcriptomes with single-cell resolution, a long-standing goal in biology, to answer fundamental questions about gene regulation. The main objective concerns gene regulation during in vivo differentiation and in pluripotent cells by studying single-cells from murine preimplantation embryos, a model system with natural single-cell resolution, important biology and medical potential. This would also allow us to explore general regulatory principles of gene expression programs of individual cells. This research program will be accomplished by novel deep sequencing technology of mRNAs (mRNA-Seq) to obtain quantitative, unbiased and genome-wide gene and isoform expression measurements. We are therefore developing new experimental and computational methods for genome-wide analyses of transcriptomes at single-cell resolution. The biological significances of the proposed research are unique insights into early embryonic development. Deep sequencing of transcriptomes will also reveal post-transcriptional gene regulation important for pluripotent cells and identified pluripotency-specific gene and isoform expressions will be important for future stem cell based therapies. The inherit single-cell nature of the model system together with its important biology makes it a model systems exceptionally well suited for a systems biology approach aiming to characterize gene regulation at single-cell resolution. The novel methodology has tremendous potential to enable complete mRNA characterization of individual cells. The deep sequencing approach with state-of-the-art computational analyses is both more quantitative than previous methods and it will give readouts on alternative isoforms generated by alternative promoters, splicing and polyadenylation.

1 654 384 €

Start date: 2010-02-01, End date: 2015-01-31

I propose to develop sophisticated anti-tumor agents targeted particularly to the location of activity. My team has recently introduced a new family of Ti(IV) complexes that demonstrates higher activity than known compounds with substantially higher stability and defined hydrolytic behavior, properties that were found to be essential. I propose to study various derivatives and identify the parameters affecting activity, including steric and electronic effects, enantiomeric purity, ligand lability etc., and elucidation various mechanistic aspects of reactivity. More importantly, I propose to construct pH-sensitive transport units that will allow protection of the sensitive active species throughout their delivery and release only near the target location based on the variable pH conditions of different human tissues. In particular, unique spherical molecules held together by metal-ligand interactions will be prepared. The building blocks will consist of the planar ligands of C3-axis bound to three biocompatible Ti(IV) ions each with defined angles and geometry. The resulting spherical compounds will be utilized to encapsulate the active complexes and release them upon hydrolysis at the desired pH based on the pH-dependent hydrolysis pattern already established for related compounds. Preliminary calculations have confirmed the possibility of forming these compounds, which are particularly matching in their expected size to encapsulate our complexes. Larger spheres will also be prepared as cavities for larger molecules, which may be linked together for the delivery of multiple drugs. These compounds may find applications in various areas where a protected environment or delivery of sensitive compounds is required, such as in gene therapy, nano-technology, and catalysis.

1 400 000 €

Start date: 2009-10-01, End date: 2014-09-30

Many natural structures are made of soft tissue that undergoes complicated continuous shape transformations that accurately and reliably serve specific elaborate tasks. Such processes can be slow, as in growth of a tissue, leading from an initial, featureless, shape to the desired elaborate structure of the adult organ. In other cases continuous shape transformations of soft tissue are rapid and are used for the production of mechanical work, as in the case of the action of the hart. Our understanding of natural growth is limited and our ability to produce controlled motions of soft tissue is poor. A central problem in both cases is how to incorporate all local changes in the tissue in order to determine the mechanical state of the entire body. In addition, there are problems regarding how to measure a deforming body and how to characterize the deformation. Finally, there is a problem of how to control motion and growth in artificial and natural soft tissues. I propose a multi disciplinary study, based on an approach I have started developing. According to it there is an underlying common mathematical way to describe continuous large shape transformations of stretchable tissues. This approach clearly defines the way to determine the mechanical state of a deformed tissue and to measure its local growth/deformation. The project will involve a theoretical study within mechanics and differential geometry, an experimental-physics work, which will be focused on the construction of responsive deformable tissue elements and measurements of their shape evolution, and a biophysical work, in which the natural growth and motion of leaves will be measured and will be correlated with biological activities. Such an integrative study has the potential of advancing our understanding of the fascinating process of growth and to improve our ability to construct bio-inspired "soft machinery".

1 000 000 €

Start date: 2009-12-01, End date: 2014-11-30

This proposal shows a new path to explore frontiers in quantum many-body physics using degenerate atomic gases. We will address fundamental open questions, create novel quantum-many body systems and seek applications beyond the realm of quantum gases. A two-component Fermi gas in an optical lattice is a unique realisation of the Fermi-Hubbard model and it is intimately linked to elementary concepts and open questions in many-body physics. We will develop novel tools for continuous cooling and detection of fermionic atoms in optical lattices. This will enable us to enter the anti-ferromagnetic phase and to study fundamental questions concerning the interplay between localization, coherence and spin-ordering in quantum many-body systems. An intriguing direction towards the creation of novel quantum many-body systems is the coupling of a strongly correlated quantum gas to an optical cavity. Here the cavity creates an effective long-range interaction with global character. This will bring together the physics of strongly-correlated systems and non-linear phenomena using a microscopically accessible system. In this highly explorative field we envisage, as a first experiment, a study of cavity-driven self-organization which may allow us to identify a novel form of a supersolid phase. Rather than investigating or manipulating the quantum gas using light we will also invert this approach and study the light after the interaction with a quantum gas inside a cavity. Using cavity opto-mechanical effects and a van der-Waals blockade by Rydberg atoms excited inside the cavity we will explore squeezing of the light and a novel photon blockade.

2 000 000 €

Start date: 2010-03-01, End date: 2015-02-28

The proposed research concerns two sets of issues. The first concerns the role of state building in the development process, and the role played by violent conflict whether internal or external to the state. In this research, we will build a sequence of theoretical models, taking a stepping stone in a basic framework where new infrastructure that expands the state s capacity to raise revenue and to support private markets is viewed as outcome of investments under uncertainty. Our objective in model building is to provide guidance for the collection of historical and contemporary data and for econometric testing, which will both be central to the project. The overall goal of this project is to bring the analysis of state capacity into the mainstream of economics, and thereby shed light on the complex interactions between state building, conflict and development. The second set of issues ultimately concerns the economics of climate change. A first subproject aims at estimating the historical effects of weather on infant mortality in Africa, using a variety of data sources: individual data based on retrospective DHS surveys, finely-gridded weather data based on so-called re-analyis with large-scale climate models, and spatial data on harvest times based on satellite data on plant growth. Exploiting the random component of historical weather fluctuation allows us to estimate causal effects on health outcomes via mechanisms like malnutrition and malaria. This initial research will serve as a pilot study, to develop a methodology for studying the weather impacts on any outcome of interest anywhere in the world. Eventually such estimates will serve to estimate the future costs of climate change.

1 489 744 €

Start date: 2010-02-01, End date: 2015-01-31

This proposal envisages a research program in the field of systems and signals that will lead to innovative and agile mathematical modeling as well as model-based signal processing and control tools for applications in biology and medicine. The project's goal is to bridge the gap between systems biology, on one hand, and medical signal processing and control engineering, on the other. Mathematical models of systems biology will be used to devise algorithms for biological data processing and computerized medical interventions. Experimental biological and clinical data will be utilized to estimate and characterize the parameters of mathematical models derived for biological phenomena and mechanisms. An extensive collaboration network of medical researchers from Sweden and abroad will provide the project team with necessary experimental data as well as with access to medical competence. The envisaged tools are expected to be applicable more generally but their efficacy will be demonstrated in two main application areas. These areas are endocrinology and neurology for which the use of formal control engineering and signal processing methods is currently deemed to be most promising. The proposed program will result in novel systems and signals tools for medical research and health care enabling multi-input multi-output modeling and analysis of endocrine regulations and providing model-based algorithms for individualized drug dose titration.

2 379 000 €

Start date: 2010-04-01, End date: 2015-03-31

The main objective of this interdisciplinary research project is to elucidate regulatory mechanisms through which the circadian timing system coordinates temporal physiology. This system has a hierarchical architecture, in that a master clock in the brain s suprachiasmatic nucleus synchronizes subsidiary oscillators in nearly all body cells. The establishment of phase coherence is obviously of utmost importance in the coordination of circadian physiology. While recent studies have identified feeding cycles, hormone rhythms, and body temperature oscillations as timing cues for peripheral clocks, the molecular makeup of the involved signalling mechanisms is largely unknown. Using liver and cultured cells as model systems, we will employ two innovative strategies for the elucidation of relevant signalling pathways. (1) STAR-Prom (Synthetic TAndem Repeat-PROmoter display), a technique developed in our laboratory, will hopefully identify most if not all immediate early transcription factors activated in cultured cells by rhythmic blood-borne and temperature-dependent signals. (2) A transgenic mouse model with conditionally active liver clocks will be explored in the genome-wide identification of coding and non-coding transcripts whose rhythmic accumulation is system-driven. The in vivo significance of the components emerging from these approaches will be assessed via RNA interference. Thus, relevant siRNAs will be injected into the tail vein of mice, and their effect on the phase of circadian liver gene expression will be monitored in freely moving mice by using whole body fluorescence imaging. Physiologically important components will serve as entry points for the identification of upstream and downstream constituents in the corresponding signal transduction cascades.

2 360 136 €

Start date: 2010-04-01, End date: 2015-12-31

The goal of this project is to develop Tropical Geometry, a newly emerging kind of algebraic geometry. It is expected to be more powerful than Classical Geometry in a range of applications (particularly in Physics-minded applications). In the same time it is significantly simpler in several mathematical aspects. In the last decade a number of initial applications of this new geometry has appeared with a success, particularly in the framework of the so-called Gromov-Witten theory, based on curves, i.e. 1-dimensional algebraic varieties. The new subject became known as Tropical Geometry since algebraically it is a based on the so-called ``Tropical Calculus'' of Computer Science. In the tropical world the curves are metric graphs, sometimes enhanced with additional structure. Stepping forward from my recent successes in set-up and application of Tropical Geometry I plan to continue this work. Particularly I plan to advance the following challenging lines of research: Solve several classical complex enumerative problems, particularly compute ZeuthenÕs characteristic numbers. Develop tropical homology theories. Advance the theory of amoebas and coamoebas (algae) of algebraic varieties. Advance understanding of real algebraic geometry. Establish direct relation between Feynman diagrams and tropical curves. Break Òthe Gromov-Witten barrierÓ in Enumerative Geometry. Develop birational tropical geometry in higher dimensions. These directions are intrinsically related in their scope and suggested methodology. Some of the proposed goals are very ambitious, but even partial advances would mean a big step forward.

1 928 800 €

Start date: 2010-01-01, End date: 2014-12-31

Multidimensional nuclear magnetic resonance (nD NMR) plays a unique role in Science as a primary tool for the characterization of biomolecules, as part of drug-discovery processes, and in clinical imaging (MRI). Further progress in NMR is hampered by this spectroscopy s low sensitivity, arising from the weak interactions that it involves. The prospects of solving this problem by continuing with incremental bigger machines approaches are poor, given the high maturity reached by existing technologies. The present Project deals with this issue by departing from traditional concepts, and relying on two incipient but highly promising developments in the field. One of these pertains ex situ dynamic nuclear hyperpolarization, an approach capable of eliciting liquid state NMR signals that surpass those afforded by the highest-field spectrometers by factors e10,000. While capable of providing super-signals hyperpolarization has the drawback of involving irreversible changes in the physical state of the sample. This makes it incompatible with nD NMR technologies, requiring the collection of multiple scans identical to one another except for systematic delay variations. As second component in this high-risk/high-gain Project we propose merging hyperpolarization with "ultrafast" methods that we have recently developed for completing arbitrary nD NMR/MRI acquisitions within a single scan. The resulting synergy could increase sensitivity by orders of magnitude, while demanding negligibly small amounts of spectrometer/scanner time to complete nD acquisitions. This should provide an ideal starting point for the analysis of a variety of organic and structural biology problems, and provide new tools to explore in vivo metabolism focusing on cancer biomarkers.

2 499 780 €

Start date: 2010-03-01, End date: 2015-02-28

This proposal is devoted to the synthesis of ultra-pure semiconductor nanowire heterostructures for energy conversion applications in the photovoltaic domain. Nanowires are filamentary crystals with a very high ratio of length to diameter, the latter being in the nanometer range. Nanowires are of significant interest owing to their large surface-to-volume ratio and low-dimensional properties, as well as attractive building blocks of novel devices, including for novel energy conversion applications. The most widely employed nanowire growth method relies on the use of gold, which is known to be an impurity limiting mobility and carrier lifetime in semiconductors. It is generally realized that nanowires with higher purity could enable significant advances in both fundamental studies and technological applications. This proposal combines two complementary and essential aspects of semiconductor nanowires: (i) synthesis in extremely clean conditions and (ii) their application to new concepts of photovoltaic devices. The first part involves the use of Molecular Beam Epitaxy (MBE) system for the synthesis of III-V semiconductor nanowires and heterostructures. Special emphasis will be given in the synthesis of new heterostructure designs, i.e. across the nanowire radius and along the growth axis. The fabrication of ordered arrays of nanowires on large areas and on silicon substrates will also be investigated. In the second part, nanowire based solar cells will be designed, fabricated and characterized. Particular emphasis will be given toward understanding the role of geometry and interfaces in the energy conversion efficiency of the novel nanowire-based solar cells. Here, the high cleanliness and precise heteroepitaxial growth of MBE nanowires will allow us to perform fundamental studies, generating ground-breaking knowledge on the microscopic processes in energy conversion. This project will foster the use of nanotechnology in the energy challenges of the XXI century.

1 286 000 €

Start date: 2010-01-01, End date: 2014-12-31