Openings in other groups

Atomic scale simulation of the degradation of zirconia bioceramics

2012-05-24T11:25:45Z

PhD available at INSA-LYON (National Institute of Applied Science) and University Claude Bernard Lyon 1, University of Lyon, within the Marie Curie Initial Training Network BIOBONE: Bioceramics for Bone Repair.

Title of the PhD: Atomic scale simulation of the degradation of zirconia bioceramics

The fellowship is for a period of 3 years. The starting date of this position is no later than 01.10.2012

Description of the BIOBONE Network and the project:

The continuous advances in the treatment of damaged and diseased bone will lead to a strong demand for new treatments and the qualified professionals able to develop and implement them. Due to their unique properties, the use of ceramics for bone substitution and engineering is expanding fast. Ceramics are currently making inroads in high volume applications such as dental or orthopaedic implants. However, much work is still needed for them to reach their full potential. This work will demand new scientists and engineers with multidisciplinary backgrounds incorporating fields as diverse as materials science and engineering, orthopaedics, tissue engineering, biology, chemistry and biomedical engineering. The objective of this network is to train young researchers to fill this demand in the strategic area of bioceramics for bone repair. 12 PhD and 6 Post-doc will be involved, in 6 academic institutions and 3 industrial partners, all at the cutting-edge of their respective fields. BIOBONE will combine hands-on training in the main host institution, exchanges with other partners and seminars.

Description of the PhD subject:

Zirconia ceramics are the only oxide technical ceramics able to be used as structural bio- ceramics withstanding very high loads for long durations, which makes them ideal options for orthopaedic and dental implants. However, after 20 years of research and hundreds of papers, there are still many questions on the physico-chemistry of aging of zirconia bioceramics. Aging occurs in zirconia ceramics due to a tetragonal to monoclinic transformation triggered by humid atmospheres or water. Our goal is to understand aging at the atomic scale (adsorption, diffusion of water derived species, lattice changes, role of Yttria and oxygen vacancies). Ab-initio and molecular dynamics calculations will be used to model surface- water interactions and near surface diffusion, as well as to understand the role of water on the stability of the tetragonal phase. The results will be validated experimentally through systematic mechanical and structural characterization at multiple length scales, especially at the nano-level. Visits and training activities are planed at Imperial College London (for a total duration of approx. 6 months).

Requirements/qualifications:

Candidates for these fellowships are expected to be in the upper segment of their class with respect to academic credentials and hands-on experiences. Applicants must hold a Master’s degree or equivalent in theoretical physics, physics or chemistry at the moment of appointment. It is advantageous that the candidate is familiar with the field of statistical physics, solid-state physics and quantum simulations and has experience with numerical simulation techniques and procedures like ab-initio and molecular dynamics.

A good command of English is required. There are no specific requirements concerning skills in French language (courses will be offered). At the time of selection by the host organization, the researcher may not have resided or carried out his/her main activity in France for more than 12 months in the 3 years immediately prior to his/her appointment. Short stays such as holidays are not taken into account.

Salary:

The PhD researcher will receive a competitive salary (approx. 1800€ net/month) and generous allowances (from 800 to 1100€ monthly depending on family situation) for travel and for participation in the training and research events of the Network.

The application must include:

- Application letter containing research interests career plans and the reasons for applying - CV (summarizing education, positions and academic work - scientific publications)
- Copies of educational certificates, transcript of records and letters of recommendation
- Details of internationally recognised language qualifications achieved.

- List of publications and academic work that the applicant wishes to be considered by the evaluation committee
- Names and contact details of 2-3 references (name, relation to candidate, e-mail and telephone number)

All documents should be in English. The application deadline is 20 June 2012.

Contacts:

Prof. Jérôme Chevalier Jerome.chevalier@insa-lyon.fr Dr. Laurent Gremillard Laurent.gremillard@insa-lyon.fr Dr. Tristan Albaret tristan.albaret@univ-lyon1.fr

Characterization of nanoporous oxides containing aqueous heavy metallic ions

2012-05-24T11:25:45Z

Cation-rich aluminosilicates, which include clays and zeolites, are some of the principal minerals found on the Earth’s surface.1 Their abundance, coupled with their ability to act as retention barriers for heavy metals, explains their involvement in a number of environmental and industrial contexts.2 These minerals play a key role in the dissemination of toxic pollutants in the environment, especially near industrial sites, but also in current remediation strategies. In all these contexts, it is paramount that we acquire a better understanding and capacity to predict how charged, radioactive or toxic metals are transported through and sorbed by these nanoporous minerals.

Molecular modelling is widely recognized as an essential tool for this purpose, as it complements macroscopic experiments by allowing researchers to uncover and single out the microscopic mechanisms at play.3,4 Classical molecular simulations, which are required to compute the properties relevant to sorption, however, rely on an accurate description of interactions on the atomic scale. Such models are still lacking for heavy metals in contact with aluminosilicate surfaces. The aim of this project is to develop the microscopic models that will be used to predict the structural, thermodynamics and dynamics properties of heavy cationic species interacting covalently with functional groups found on the surface of nanoporous oxides. Theoretical predictions will be compared to experimental results obtained within a collaboration with the Laboratoire de Réactivité de Surface (UPMC, Paris).

Funding This grant is funded by the DIM-Oxymore Network on functional oxides (Région Ile-de-France)

Contact Anne Boutin (anne.boutin@ens.fr)
Laboratoire PASTEUR, Département de Chimie, Ecole Normale Supérieure, Paris www.chimie.ens.fr

Benjamin Rotenberg (benjamin.rotenberg@upmc.fr)
Laboratoire PECSA, UPMC (Université Pierre et Marie Curie), Paris www.pecsa.upmc.fr

1. B. Rotenberg, A. J. Patel and D. Chandler, J. Am. Chem. Soc., 2011, 133, 20521.
2. V. Marry, B. Rotenberg and P. Turq, Phys. Chem. Chem. Phys., 2008, 10, 4802.
3. B. Rotenberg, V. Marry, R. Vuilleumier, N. Malikova, C. Simon and P. Turq, Geochim. Cosmochim. Acta, 2007, 71, 5089. 4. M. Jeffroy, A. Boutin and A.H. Fuchs, J. Phys. Chem. B, 2011, 115, 15059.

Graduate student position at the University of Texas-Austin

2012-01-14T11:14:26Z

Graduate student positions are available in the Elber group at the University of Texas at Austin to conduct Molecular Dynamics simulations of long time processes of biological molecules. Examples are protein conformational transitions, transport through membrane, RNA folding, and molecular machines. A few relevant publications are listed at the end of this message. Interest in scientific programming and statistical mechanics are requirements. Background in chemistry and biology is a plus. Interested candidates should contact ron@ices.utexas.edu. Students in the Elber's group are from three graduate programs in University of Texas at Austin : Computer Science, Computational Science and Engineering Math, and Chemistry and Biochemistry. Candidate should indicate which program they prefer to apply.

Steven Kreuzer, Ron Elber and Tess J Moon, “Early Events in Helix Unfolding Under External Forces: A Milestoning Analysis”, J. Phys. Chem. B, 116,8662–8691(2012)
Serdal Kirmizialtin, Virginia Nguyen, Kenneth A Johnson, and Ron Elber, “How Conformational Dynamics of DNA Polymerase Select Correct Substrates: Experiments and Simulations”, Structure, 20,618-627(2012)
Serdal Kirmizialtin and Ron Elber, “Revisiting and Computing Reaction Coordinates with Directional Milestoning”, J. Phys. Chem. A, 115,6137-6148(2011).