Selected Fellows Call 2013

Below you will find an overview of the proposals of the successful candidates of the 2013 call by alphabetical order.

To explore the scientific outputs of our fellows, please search them on Infoscience.

Supramolecular interacting materials for solar energy conversion

Laboratory of Photonics and Interfaces (LPI)

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Abate Antonio - Portrait
Antonio Abate
©Antonio Abate

Converting sunlight into electricity is one the most promising solutions to satisfying the growing energy demand. Different materials have been used to realize solar cells that can produce clean and renewable energy directly from sun.

The first operational solar cells were prepared in 1954 using silicon, and were used to power orbiting satellites and other spacecrafts. However, their manufacturing costs made solar energy impractical for large scale power generation. Thereafter, a number of new materials and fabrication procedures have attracted a growing effort in order to realize fundamentally lower-cost technologies. Very recently, perovskites, one of the most abundant classes of materials on earth, have been demonstrated as valuable materials for solar energy conversion.

In this project I will exploit perovskite materials in order to deliver a low-cost alternative to the established silicon technologies. A perovskite-based solar cell comprises an assembly of several organic and inorganic materials, which are integrated in a whole device. Here, I will make use of specific chemistry, such as supramolecular interactions, to control the material interfaces, which I believe is crucial to preparing efficient and stable perovskite solar cells.

(Start date of fellowship: 1 July 2014)

Perovskites: new materials for solar energy conversion.
Perovskites: new materials for solar energy conversion.
©Nano Letters (ACS Publications)

Adaptive low-rank tensor methods

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Jonas Ballani Portrait - © Jonas Ballani
Jonas Ballani
©Jonas Ballani

Many real-world applications require the treatment of a large number of parameters. Typically, the amount of data that needs to be represented scales exponentially in the parameter dimension. Therefore, a crucial task is to develop special numerical techniques that rely on data-sparsity in order to cope even with high parameter dimensions.

A quite successful and promising technique to reach this goal is based on low-rank tensor representations. In this approach, data-sparsity is obtained by identifying suitable low-rank tensor structures in high-dimensional data sets. As a powerful and flexible framework, the hierarchical tensor format provides both an efficient means for the representation and approximation of data with a complexity that scales only linearly in the parameter dimension.

The aim of this project is to construct approximations in this format from a relatively small set of data samples which can either be prescribed by the application or by the user. Our goal is to adapt the format to the given data such that the complexity of the final representation is as small as possible. Applications range from the solution of high-dimensional partial differential equations and the fast online optimization of parameters up to efficient data compression schemes.

(Start date of fellowship: 1 March 2014)

Hierarchical tensor representation of high-dimensional data
©Jonas Ballani

Degradation and turnover of extracellular DNA in aerobic granules of polyphosphate (PAO)- and glycogen (GAO)-accumulating organisms

Laboratory for Environmental Biotechnology (LBE)

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Bialek Katarzyna
Katarzyna Bialek
©Jakub Bialek

Enhanced biological phosphorus removal (EBPR) enables phosphorus recovery from waste streams and is a technology that could satisfy 15-20% of the world phosphate demand. The process relies on the specific group of bacteria called polyphosphate accumulating organisms (PAO), to take up phosphate from wastewater in excess of their growth requirements, store it in intracellular granules, which can be further recovered and utilized.

Competition for carbon source between PAO and glycogen accumulating organisms (GAO) can lead to process instability and is considered a serious impediment to the implementation of EBPR plants in warmer climates. The granule formation and specific properties of granules strongly depend on the structure of the extracellular polymeric substances (EPS) in which the microorganisms are embedded.

Apart from major EPS components, i.e. proteins and polysaccharides, extracellular DNA (eDNA) has been recently recognized as an important structural component in activated sludge biofilms.

However, the status of current knowledge does not include studies involving investigating the role and turnover rates of eDNA in aerobic granular sludge. Therefore, the current proposal will help to elucidate the role and mechanisms of eDNA transformation in aerobic granules of polyphosphate (PAO)- and glycogen (GAO)-accumulating organisms.

(Start date of fellowship: 1 July 2014)

Extracellular DNA in aerobic granules of polyphosphate (PAO) and glycogen (GAO) accumulating organisms as a main topic in research investigating the role and mechanisms of eDNA transformation.
Diagram made by Katarzyna Bialek, using schematics of the reactors, picture of aerobic granules and the idea of extracellular DNA. The schematics of the reactors and picture of aerobic granule originate from the PhD thesis of Weissbrodt DG (2012) PhD Thesis, No. 5641, EPFL, Switzerland Bacterial Resource Management for Nutrient Removal in Aerobic Granular Sludge Wastewater Treatment Systems.

Quantum quench across a quantum critical point

Laboratory for Quantum Magnetism (LQM)

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Chung Mingee Portrait
Chung Mingee
©Hee Jin Kim

All matter changes its state and properties upon heating or cooling. A piece of Copper melts above a thousand degree and water freezes into ice at zero degree Celsius.

The driving force behind is thermal agitation of the constituent particles like atoms or electrons. One may then naturally expect no room for such change at absolute zero temperature where thermal fluctuations simply does not exist. However, in nature, there exists another form of agitation – quantum fluctuations – resulting from Heisenberg’s uncertainty principle, which is so feeble at ordinary temperatures yet survives even at absolute zero temperature.

By applying pressure or a magnetic field, this zero-temperature agitation can be amplified to give rise to a fundamental state change. At the border between the states, called a quantum critical point, lie the keys, scientists believe, to understanding of many mysterious properties of matter like unconventional superconductivity. However, current understanding is largely limited to a smeared average image of equilibrium properties.

I propose instead to develop a new method capable of recording a dynamic movie of what happens across a quantum critical point out of equilibrium. When successful, it will open a new avenue toward deeper understanding of matter and help us design materials of novel properties.

(Start date of fellowship: 1 June 2014)

Controlling entangled quantum spins in a magnetic crystal
Controlling entangled quantum spins in a magnetic crystal
©Chung Mingee

Atherosclerotic plaque destruction by sub-surface, non-thermal ablation

Optics Laboratory (LO)

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Donal Conkey portrait
Donald Conkey
©Donald Conkey

Cardiovascular disease is Europe’s main cause of death; killing millions each year. One of the major causes of cardiovascular disease is atherosclerosis, or the accumulation of fatty plaque in the arteries. Importantly, the plaque is surrounded by a tissue layer, which, when ruptured, releases plaque into the artery and may form a lethal blood clot. Unfortunately, current atherosclerosis treatments are either highly invasive or only partially effective.

To address this problem we are developing a device which would destroy atherosclerotic plaque through non-thermal ablation and wavefront shaping. Non-thermal ablation occurs when tissue is ionized inside the focus of a high peak intensity laser pulse. Destruction of plaque with non-thermal ablation allows for sub-surface ablation with high resolution and control. Wavefront shaping for controlling light through turbid media will allow focus creation and ablation deep inside the plaque.

For this project we are characterizing the non-thermal ablation damage, developing a means of delivering the high peak power pulse to the arterial plaque, and implementing wavefront shaping to deliver high peak power pulsed light through the tissue. The device will provide a new method for treating atherosclerosis and has potential to improve the health of millions of people.

(Start date of fellowship: 1 February 2014)

Laser-induced optical breakdown in the plaque
The proposed catheter device would focus laser pulses under the surface tissue layer and into the atherosclerotic plaque. The high-intensity, ultrafast laser pulse would initiate laser-induced optical breakdown in the plaque, without damaging the surrounding tissue layer.
©Donald Conkey

Ultrafast spectroscopy of GaN nanostructures

Laboratory of Quantum Optoelectronics (LOEQ)

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Gwénolé Jacopin
Gwénolé Jacopin
©Jérôme Tiphaine

III-nitride semiconductors have now become the second most important market after silicon. This is mostly due to blue and white light emitting diodes (LEDs) and blue lasers.

Interestingly, even if the industry commercializes optoelectronic devices based on this family of semiconductors, many unsolved physical issues still remain. As a striking example, both researchers and industry failed to develop high power white LEDs with high efficiency.

This issue is referred to the literature as the efficiency droop, which means that the LED efficiency dramatically drops with increasing current density. Even more important, researchers still disagree about the origin of this effect. Indeed, in III-nitride nanostructures, it appears that the physics is more complex than in traditional III-V semiconductors because of the interplay between the internal electric field, the high density of defects, and the large exciton binding energy.

In my project, I propose to use both time-resolved and spatially-resolved techniques to investigate and understand in detail the efficiency of III-nitride nanostructures. The results of this research may lead to innovative designs overcoming identified issues.

Fellowship dates: 1 April – 31 December 2014)

Spectral and temporal dependence
Spectral and temporal dependence of the photoluminescence of an III-nitride quantum well under high injection
©Gwénolé Jacopin

Novel spinal cord stimulation therapy to alleviate gait deficiencies in people with Parkinson’s disease

IRP Chair on Spinal Cord Repair (UPCOURTINE)

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Tomislav Milekovic
Tomislav Milekovic
©Tomislav Milekovic

Over 6 million people worldwide suffer from Parkinson’s disease (PD), with disabilities that dramatically affect their quality of life. Pharmacotherapies and deep brain stimulation efficiently alleviate some of the motor symptoms of PD, but gait deficits are resistant to currently available treatments.

In this project, we will leverage recent technological and conceptual developments to design a neuroprosthetic treatment for alleviating gait disorders in PD.

We first aim to map the neural states in the motor cortex to whole-body kinematics and muscle synergies during natural locomotor tasks in non-human primates (NHPs). To this end, we will exploit a recently established translational platform that enables real-time recording of neuronal ensemble activity, muscle activity, and whole-body kinematics in freely walking NHPs. We will monitor changes in neural states and locomotor control strategies in the same animals during the development of PD motor symptoms.

Finally, we will adjust neuromodulation therapies of spinal circuits based on detected pathological neural states in the motor cortex to alleviate gait deficits in NHP model of PD. Efficient translation of neuroprosthetic treatments into viable therapies for PD patients critically relies on the validation and optimization of procedures and technology in relevant animal models prior to clinical trials.

(Start date fellowship: 1 June 2014)

Project illustration
Corticospinal neuroprosthesis to alleviate gait deficits in Parkinson’s disease. We will leverage two novel, cutting-edge wireless technologies (A) to monitor cortical population dynamics in real-time, and (B) to deliver electrical spinal cord stimulation in a non-human primate model of Parkinson’s disease. These neuro-technologies will support the design of a corticospinal neuroprosthesis whereby motor cortex activity will directly modulate spinal circuits to improve gait and balance.
©Medtronic Inc., Gregoire Courtine, David Borton Allenson, Tomislav Milekovic and Erwan Bezard

Chemical characterization of atmospheric organic aerosols by online FTIR spectroscopy

Atmospheric Particle Research Laboratory (APRL)

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Lewis Modini portrait
Rob Modini
©Giulia Ruggeri

Atmospheric aerosols are small particles suspended in the Earth’s atmo- sphere. Inhalation of these particles leads to significant adverse health effects and each year aerosols are the cause of millions of premature deaths worldwide. Atmospheric aerosols also exert a significant influence on global climate by scattering sunlight and acting as the seeds onto which clouds form, thereby altering the Earth’s energy balance. Atmospheric aerosols have both natural and human-made sources and are composed of organic compounds, inorganic salts, dust, soot, and water.

The organic compounds are always present and form 20-90% of the total submicrometer aerosol mass. However, this organic fraction is typically a complex mixture of thousands of different compounds, and our knowledge and understanding of its composition is incomplete. Consequently, despite their ubiquity, organic aerosols constitute the largest uncertainty in predictions of the health and climate impacts of atmospheric aerosols.

The goal of this research project is to reduce this uncertainty through the development of a novel device for measuring the chemical composition of organic aerosols. The device will consist of a particle collection system integrated with an infrared spectrometer. Measurements collected with this device will be used to evaluate model predictions of environmentally important aerosol properties.

(Start date fellowship: 1 August 2014)

project picture
Atmospheric aerosols are small particles suspended in the Earth’s atmosphere.
©Satoshi Takahama

Photon Absorption enhancement by conformal Coating of Microstructured surfaces with Ag Nanoparticles (PACMAN)

Polymers Laboratory (LP)

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John Moraes
John Moraes
©Raoul Peltier, 2013

Solar cells are an important part of a future in which electricity is sustainably generated. While conventional solar panels are made up of flat silicon semiconductors, the new generation of solar panels is likely to be made up of micro-structured semiconductors. These surfaces – such as micro-pillars or nano-wires – hold the promise of increased electricity-generation efficiency. A crucial part of solar cells is the transparent, conductive coating that covers the semiconductor. This is currently achieved by using a material called indium tin oxide (ITO). However since indium is a globally-scarce resource, I would like to find an alternative to this method.

My project investigates the use of silver (Ag) nano-particles to coat the semiconductor surfaces. This will not only serve to eliminate ITO from the panel, but will also provide an increased efficiency to the device due to a property of metallic nano-particles called surface plasmon resonance. To coat a micro-structured surface with the nano-particles, I will first grow polymer chains onto the semiconductor surface and use these to seed the growth of the nano-particles. The polymer layer will then be removed to give a uniformly-coated semiconductor surface. This is how I hope to make indium-free highly-efficient solar cells.

(Fellowship dates : 1 April 2014 – 30 September 2015)

Project illustration
Conformal coating of a micro-pillar array: 1) grafting a polymer template, 2) growing silver nano-particles within the polymer chains and 3) removal of the polymer template.
©John Moraes, 2014

Molecular and polymeric nanostructures based on boronic acids

Laboratory of Supramolecular Chemistry (LCS)

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Marcus Papmeyer Portrait
Marcus Papmeyer
©Kay Severin

In nature, self-assembly of building blocks to highly complex molecular architectures is a fundamental process that is essential for the functioning of life. For example, the building block tubulin, a small cylindrical-shaped protein, aligns in cells in an end-to-end manner to form microtubulus rods which serve as molecular highways for the transport of cargo from the cell nucleus to the periphery.

This prevalent, powerful bottom-up approach found in nature has inspired us to work on the development of new methodologies for the construction of functional artificial nanostructures and novel materials. In a ‘molecular-Lego’ fashion, based on boron chemistry, we hope to access structures by self-assembly of tailor-made building blocks. Assembling multiple components, cage compounds with defined cavity sizes and materials with enormous surface areas should be accessible. These novel materials will enable gas absorption and storage and build the basis for materials with more advanced functionalities.

Similarly, a second focus of the project is the construction of interlocked architectures based on self-assembly of individual components that are essential for the construction of molecular machines and hold great promise for future applications.

(Start date fellowship: 1 April 2014)

Molecular models of a cage compound and a [2]rotaxane
Figure: Molecular models of a cage compound (left) and a [2]rotaxane (right).
©Marcus Papmeyer

Microbial cycling of arsenic in rice paddies: Environmental controls on arsenic methylation and implications for uptake into rice plants

Environmental Microbiology Laboratory (EML)

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Matthew Raid Portrait
Matthew Reid
©Matthew Reid

Four of the five largest global rice producers are characterized by widespread naturally-occuring or anthropogenic arsenic contamination in soils and/or groundwater. Rice plants effectively take up arsenic from contaminated soil and concentrate it in rice grains, and chronic exposure to arsenic in rice is a growing human health concern. Methylayed forms of arsenic are particularly important for rice contamination because they are very efficiently transported from roots to rice grains, yet little is known about the microbial community involved in arsenic methylation and how its activity is regulated by soil environmental conditions.

This project will combine laboratory experiments with cutting-edge microbial, geochemical, and spectroscopic analyses to gain mechanistic insight into the interactions between microbes, organic forms of arsenic, and rice plants. Experiments will be informed by hydrological and soil biogeochemical conditions in the Mekong Delta in Southern Vietnam, which is a vital region for rice cultivation and where sediment and groundwater contamination is widespread.

This research will yield new insights into how the microbial community responsible for arsenic methylation is affected by processes including irrigation practices and salt water intrusion, with important implications for the mitigation of arsenic contamination of rice.

(Start date fellowship: 1 July 2014)

Project picture
Photograph of the field site in the upper Mekong Delta, An Giang Province, Vietnam. Conditions from these rice paddies are used to inform the design of well-controlled laboratory experiments to understand mechanisms of arsenic uptake by rice plants.
©Rizlan Bernier-Latmani

Brain mechanisms of exteroceptive and interoceptive integration in bodily self-consciousness

Foundation Bertarelli Chair in Cognitive Neuroprosthetics (LNCO)

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Roberta Ronchi portrait
Roberta Ronchi
©Corrado Corradi Dell’Acqua

Bodily self-consciousness refers to the conscious experience of the self within the limits of the body. Manipulation of bodily information can alter critical characteristics of bodily self-consciousness, such as the feeling that a hand belongs to oneself and the perceived location of the body in space.

Recently, researchers focused their attentions on the role played by signals arising from inside the body (interoceptive signals, e.g. the heartbeat); however, little is known about the relationship between interoceptive and exteroceptive (e.g., tactile, visual) signals in generating bodily self-consciousness. This project investigates for the first time these timely questions with an integrated approach combining information from the damaged and the healthy brain.

In the first study I will apply the neuropsychological approach to investigate disorders of bodily self in neurological patients, in order to demonstrate a causal link between specific brain regions and bodily self-consciousness. In the second study I will elucidate the neural mechanisms underlying bodily self-consciousness through integration of interoceptive and exteroceptive signals, by using electroencephalography.

This project might importantly contribute to theoretical advance in this field, and it will have a strong clinical impact in providing insight about how modulation of bodily self-consciousness can be used to restore bodily-related diseases.

(Start date of fellowship: 1 March 2014)

Project illustration
The image shows the set up used to modulate bodily self-consciousness by integration of interoceptive and exteroceptive signals. The person sees on the head-mounted display his body from backwards, surrounded by a glow flashing synchronously or not with respect to his heartbeat. The participant’s electrocardiogram (ECG) is recorded in real time during the experiment.
©2013, Irit Hacmun – EPFL

Coupled thermo-hydro-mechanical analysis of carbon dioxide (CO2) storage in deep saline formations

Laboratory of Soil Mechanics  (LMS)

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Victor Vilarrasa portrait
Victor Vilarrasa
©Daniel Riaño

Huge amounts of carbon dioxide (CO2) are emitted to the atmosphere (above 30 Gt/yr)as a result of our dependence on fossil fuels for power generation. Since CO2 is a greenhouse gas, it alters atmospheric circulation and contributes to climate change. The energy market will require a change towards low-carbon technologies, but this transition can last several decades. Thus, bridge technologies, like geologic carbon storage (GCS), are necessary to minimize CO2 emissions.

GCS involves injecting CO2 in deep geological formations. Since CO2 is buoyant, a low-permeability formation overlying the storage formation is necessary to prevent CO2 from leaking towards freshwater aquifers. Pressure will increase as a results of the huge amounts of CO2 that are intended to be injected (millions of tons per year per well). Furthermore, CO2 will reach the storage formation at a lower temperature than that of the rock, which will induce thermal stresses. This overpressure and temperature difference could induce fracture instability and subsequently, trigger earthquakes.

This project aims to determine safe pressure and temperature injection conditions that guarantee the absence of induced felt seismic events. This project will contribute to gaining public acceptance by improving the knowledge on the safe injection conditions of GCS.

(Start date of fellowship: 1 January 2015)

Victor Vilarrasa project picture
Geologic carbon storage: CO2 is captured in industrial plants (1), transported through ships and pipelines (2) and injected deep underground (3) in matures oil and gas fields (A), saline aquifers (B) and unminable coal seams (C). © Pascal Coderay