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Kemifaglige foredrag 2014

20.11.2014 Prof. Dr. Christian Hertweck

Prof. Dr. Christian Hertweck 
Leibniz-Institute for Natural Product Research and Infection Biology (HKI)

Abstract:

Many compounds that are produced by bacteria and fungi can cause illnesses or intoxications. However, others are capable of curing diseases. The aim of our research projects is to identify these pharmacologically relevant compounds as well as the toxins and to understand how they are produced in microorganisms - at the chemical, biochemical and genetic levels. On the basis of this knowledge we investigate the origin and types of disease-causing substances and try to produce new therapeutics. Beyond decoding and reprogramming biosynthetic pathways this approach can shed light on the communication of microbes with other organisms.

Host: Thomas B. Poulsen, Department of Chemistry, Aarhus University


06.11.2014 Prof. Erik Swietlicki

Prof. Erik Swietlicki 
Department of Physics
Lunds Universitet 

Abstract: 

Airborne particles – atmospheric aerosols - have severe negative effects both on our health and climate. In order to find pathways towards a sustainable society, we need to understand how atmospheric particles are formed, transformed, dispersed, and how they interact with clouds and radiation. This talk will give some examples of the atmospheric aerosol research that is carried out at Lund University. Examples include (i) Laboratory and field studies of the atmospheric ageing of soot particles, and the implications for climate and health; (ii) Measurements and modelling of the formation of secondary organic aerosol; and (iii) Satellite cloud microphysical retrievals to deduce and quantify aerosol–cloud interactions. I will also give a brief overview of our plans on how to integrate our infrastructures for long-lived greenhouse gases (ICOS) and short-lived climate pollutants (ACTRIS) in Sweden.

The link between our aerosol research activities and those of MERGE, a Swedish strategic research area on climate modelling, is also outlined.

Host: Merete Bilde, Institut for Kemi, Aarhus Universitet 


24.10.2014 Prof. Clement Mazet

Prof. Clement Mazet 
Département de chimie organique

Université de Genève  

Recent advances in selective isomerizations

 

Host: Troels Skrydstrup, Institut for Kemi & iNANO, Aarhus Universitet 


23.10.2014 Dr. Arndt Remhof

Dr. Arndt Remhof
Group leader at EMPA 
Laboratory “Hydrogen and Energy.”

Structure and Dynamics of Novel Energy Materials 

Read abstract here

Host: Torben Rene Jensen, Institut for Kemi & iNANO, Aarhus Universitet 


03.10.2014 Dr. Minjin

Dr. Minjin 

 

Host: Merete Bilde, Institut for Kemi, Aarhus Universitet 


02.10.2014 Prof. Hai-Wen Li

Prof. Hai-Wen Li
International Research Center for Hydrogen Energy,
Japan

Development of Metal Borohydrides for Efficient Energy Storage

Abstract: 

The emphasis of strategic energy plan in Japan has revised from nuclear to renewable energy after the 2011 Fukushima disaster. Reliable energy supply from renewable energy such as solar and wind requires efficient energy storage systems. Storage of hydrogen produced by renewable energy in hydrides is regarded as one of the most promising ways. Metal borohydrides M(BH4)n (n is the valence of metal M) like LiBH4, Mg(BH4)2 and Ca(BH4)2, with hydrogen gravimetric density higher than 10 mass%, have been extensively investigated as potential candidates for hydrogen storage. In this talk, we will elucidate the fundamental dehydrogenation and re-hydrogenation properties. Further, we will discuss the critical issues and strategies of material designing from the viewpoint of practical applications

Host: Torben R. Jensen, Department of Chemistry, Aarhus University


19.09.2014 Dr. Frank N. Keutsch

Dr. Frank N. Keutsch 
University of Wisconsin-Madison
USA

"Missing" Volatile Organic Compounds: A Tale of Mistaken Identities and Sources

Abstract:

Tropospheric oxidation of volatile organic compounds (VOCs) is directly coupled to formation of secondary pollutants, in particular ozone and secondary organic aerosol, which affect climate and human health. Accurate mechanistic understanding of VOC oxidation across all spatial, temporal and chemical scales is critical to understanding how changing boundary conditions affect secondary pollutant concentrations. The potential to form secondary pollutants depends on (i) the amount of emitted VOCs, (ii) the rate of VOC oxidation determined oxidative capacity and by VOC concentrations, and (iii) the VOC oxidation product distribution.

See abstract here

Host: Marianne Glasius, Department of Chemistry, Aarhus University


18.09.14 Prof. Dr. Thorsten Hoffman

Prof. Dr. Thorsten Hoffmann
Johannes Gutenberg-Universität
Institut für Anorganische und Analytische Chemie
Mainz

Measurement strategies, composition and chemistry of secondary organic aerosols

Abstract:

Secondary organic aerosol is formed in the atmosphere by the reaction of VOCs with atmospheric oxidants (e.g. ozone, OH-radicals). The low volatile products can condense on pre-existing particulate matter and are potentially involved in new particle formation. Among the secondary aerosol especially the biogenic secondary organic aerosol (SOA) attracts special attention because of the large total amounts of natural VOCs (e.g. terpenes, sesquiterpenes) emitted by terrestrial vegetation. However, also inorganic biogenic emissions (i.e. iodine compounds) can influence particle formation and oxidative processes in the atmosphere. Focusing on the development and application of trace analytical strategies based on mass spectrometry, our group tries to get a better understanding of atmospheric processes, such as the heterogeneous chemistry of SOA components.

Vært: Marianne Glasius


05.09.2014 Prof. Dr. Daniel B. Werz

Prof. Dr. Daniel B. Werz 
Institute für Organische Chemie
Technical University of Braunschweig, Germany


Host: Henrik Helligsø og Thomas Poulsen, Institut for Kemi, Aarhus Universitet 


21.08.2014 Dr. Marina Kuimova

Dr. Marina Kuimova 
Faculty og Natural Sciences, Department og Chemistry 
Imperial College, London, UK

Mapping microscopic viscosity using molecular rotors, from live cells to atmospheric aerosols

Abstract:

Viscosity is one of the main factors which influence diffusion in condensed media. In a cell viscosity can play a role in several diffusion mediated processes, such as drug delivery, signalling and mass transport. Previously, alterations in viscosity in cells and organs have been linked to malfunction; however, mapping viscosity on a single-cell scale remains a challenge. We have imaged viscosity inside lipid mono- and bi-layers, in cells and in atmospheric aerosol particles using fluorescent probes, called 
molecular rotors [1]. In molecular rotors the speed of rotation about a sterically hindered bond is viscosity-dependent [1]. This approach enabled us to demonstrate that viscosity distribution in a cell is highly heterogeneous and that the local microviscosity in hydrophobic cell domains can be up to 100 times higher than that of water [2-5]. We also determine particle viscosity of complex, atmospherically relevant organic aerosols and monitor its temporal changes in real time, over time scales relevant for the atmosphere [6].

See abstract here

Host: Peter R. Ogilby, Department of Chemistry, Aarhus University


22.05.2014 Prof. Amitabha Chattopadhyay

Prof. Amitabha Chattopadhyay
Centre for Cellular and Molecular Biology,
Uppal Road, Hyderabad, India

GPCR-Cholesterol Interaction: Novel Insights in Health and Disease

Abstract: 

G protein-coupled receptors (GPCRs) are the largest class of molecules involved in signal transduction across membranes, and represent major drug targets in all clinical areas. The serotonin1A receptor is an important neurotransmitter receptor of the GPCR superfamily and is implicated in the generation and modulation of various cognitive, behavioral and developmental functions. We previously demonstrated that membrane cholesterol is necessary for ligand binding, and G-protein coupling of serotonin1A receptors.
Interestingly, recently reported crystal structures of GPCRs have shown structural evidence of cholesterol binding site(s). In this context, we reported the presence of cholesterol recognition/interaction amino acid consensus (CRAC) motifs in the serotonin1A receptor. We also showed that the receptor is more stable and compact in the presence of membrane cholesterol. Our recent results utilizing coarse-grain molecular dynamics simulations to analyze the molecular nature of receptor-cholesterol interaction offer interesting insight in cholesterol binding site(s) in the receptor and oligomerization of the receptor. We showed utilizing homo-FRET that the serotonin1A receptor is constitutively oligomerized in live cells, with the possibility of higher order oligomers of the receptor. Progress in deciphering molecular details of the nature of GPCR-cholesterol interaction in the membrane would lead to better insight into our overall understanding of GPCR function in health and disease.

See abstract here

Hosts: Birgit Schiøtt and Thomas Vosegaard, Department of Chemistry, iNANO, Aarhus University


15.05.2014 Prof. Dr. Siewert-Jan Marrink

Prof. Dr. Siewert-Jan Marrink 
Faculty of Mathematics and Natrual Sciences 
University of Groning, Nederlands 

Sorting and Clustering of Membrane Proteins in Crowded Environments

Abstract:

In this lecture, I will illustrate the power of computational modelling to study the sorting and clustering of membrane proteins in the heterogeneous environment of multicomponent lipid membranes.
In particular, based on coarse-grained molecular dynamics simulations.
I will discuss the role of lipid anchors and gangliosides in directing proteins into liquid-ordered membrane domains, as well as the role of cardiolipin in respiratory chain supercomplex formation.

Host: Birgit Schiøtt and Frans Mulder, Department of Chemistry, iNANO, Aarhus University


08.05.2014 Prof. Bo Albinsson

Prof. Bo Albinsson 
Department af Chemistry and Biotechnology,
Chalmers University of Technology, Göteborg, Sweden

Self-Assembled DNA Nanosystems for Energy and Electron Transfer Applications

Abstract: 

DNA has the possibility to self-assemble into predefined 2 and 3-dimensional objects, with a spatial resolution on the sub-nm level.1 The DNA constructs can easily be made with compositions and shapes defined at the atomic level in molar amounts in bulk phase, as compared to normal lithographic techniques in which objects are made one by one with much lower spatial resolution. These features have made DNA an interesting building block in bottom-up nanotechnology.
In this presentation I will describe how we systematically have developed 1 and 2-dimensional DNA constructs for the precise positioning of components involved in photoinduced electron transfer reactions.2 Linear and branched DNA molecules have been functionalized with lipophilic porphyrins that act as anchors in liposomes and on supported membranes.3 The porphyrin anchors, furthermore, undergo photoinduced electron transfer reactions with electron acceptors that reside in the membrane. The DNA, which resides in the water phase, can in turn act as a scaffold for antennas undergoing multi-step energy transfer reactions.4 With this flexible approach we can self-assemble a wide variety of complex energy transfer and redox components with the aim to produce a predetermined molecular pattern forming the basis for novel lithographic applications.

Se abstract her

Host: Peter R. Ogilby, Institut for Kemi, Aarhus Universitet 


03.04.2014 Prof. Dr. Stefanie Dehnen

Prof. Dr. Stefanie Dehnen 
Philipps-Universität Marburg, Germany 
Department of Chemistry, Inorganic Chemistry

„Take 2“ to Form Multinary Metallates and Intermetalloid Clusters: From Basics to Functionality

Multinary, non-oxidic metallates as well as metallides are currently actively investigated by many research groups, leading from structural studies through functional analyses to the generation of innovative materials.1 Binary main group element aggregates proved to be useful synthetic tools for a large variety of different structural and functional motifs within ternary or multinary transition metal/main group metal/non-metal clusters and networks.2

Whereas chalcogenidotrielate/tetrelate ions [E13/14xE16y]q– (E13/14 = Ga, In; Ge, Sn; E16 = S, Se, Te) may be basically viewed as heavier homologues of silicates or borates, the inversely polarized pnictogentrielide/tetrelide ions [E13/14xE15y]q– (E13/14 = Ga, In; Ge, Sn, Pb; E15 = As, Sb, Bi) have a distinct tendency to form so-called intermetalloid clusters.3

However, in both cases, the products of reactions with transition metal compounds differ significantly from any lighter homologues, as they represent unprecedented, ternary clusters or networks, according to the general type [MxE13/14yE16z]q–, or ternary Zintl anions [MxE13/14yE15z]q–. The physical properties of the compounds, which may represent (photo-)semi-conductors, ion conductors or bond-activating nano-capsules, are dependent on the nature of the involved elements and the observed structure type.4–7 Very recently, also ionothermal techniques were successfully applied for the synthesis of novel salts of such complex anions.8

See abstract here

Host: Simon Johnsen, Institut for Kemi, Aarhus Universitet  


20.02.2014 Prof. Dr. Luc Brunsveld

Prof. Dr. Luc Brundveld
Department of Biomedical Engineering
Technische Universiteit, Eindhoven 

Chemical Biology Approaches to Protein-Protein Interactions; molecular insights in nuclear receptors and caspases

Abstract:

Chemical biology is the study of biological phenomena with an approach originating from chemistry combining and integrating chemistry and biology. This lecture will focus on the application of chemical biology approaches for the study and modulation of two types of protein protein interactions: the nuclear receptor-coactivator interaction and caspase dimerization.

The nuclear receptor – cofactor interaction is the key protein-protein interaction that transfers ligand induced changes in the nuclear receptor conformation to the transcriptional machinery. A molecular understanding of this process and its regulation is necessary to fully control and predict the effects of nuclear receptor modulation, either via classical ligands or via direct modulation of this interaction. With the Estrogen Receptors as examples, chemical biology strategies to elucidate this protein-protein interaction at the molecular level are discussed. Caspase homodimerization is a key step in the activation of their enzymatic activity. Control over protein homodimerization allows investigating the molecular processes underlying this activation mechanism. We have generated a so-called supramolecular inducer of dimerization that can act as an allosteric modulator of caspase-8 and -9 activation and allows highly efficient and reversible activation of caspase activity.

 

Host: Frans Mulder, Institut for Kemi, iNANO, Aarhus Universitet


06.02.2014 Prof. Rasmus Bro

Prof. Rasmus Bro
Institut for fødevarevidenskab, kvalitet og teknologi
Københavns Universitet


Chemometrics – using all the information. Applications in metabonomics and food quality

Abstract:
In recent years, there has been a rapid development in analytical chemical instruments. One can get gigabytes of data at the touch of a button given large amounts of information. Unfortunately the data analysis in most chemical traditions are still decades or even centuries behind. That is a shame! Chemometrics allows to extract and understand complex data and this will be exemplified with applications in food quality and metabonomics.

Host: Ove Christiansen, Institut for Kemi, Aarhus Universitet