Wolfgang Knoll

Bio: Wolfgang Knoll is an academic researcher from Austrian Institute of Technology. The author has contributed to research in topics: Surface plasmon & Surface plasmon resonance. The author has an hindex of 103, co-authored 898 publications receiving 40477 citations. Previous affiliations of Wolfgang Knoll include University of Parma & Danube Private University.

Interfaces and thin films as seen by bound electromagnetic waves

Abstract: This contribution summarizes the use of plasmon surface polaritons and guided optical waves for the characterization of interfaces and thin organic films. After a short introduction to the theoretical background of evanescent wave optics, examples are given that show how this interfacial “light” can be employed to monitor thin coatings at a solid/air or solid/liquid interface. Examples are given for a very sensitive thickness determination of samples ranging from self-assembled monolayers, to multilayer assemblies prepared by the Langmuir/Blodgett/Kuhn technique or by the alternate polyelectrolyte deposition. These are complemented by the demonstration of the potential of the technique to also monitor time-dependent processes in a kinetic mode. Here, we put an emphasis on the combination set-up of surface plasmon optics with electrochemical techniques, allowing for the online characterization of various surface functionalization strategies, e.g. for (bio-) sensor purposes.

An Aqueous Route to Multicolor Photoluminescent Carbon Dots Using Silica Spheres as Carriers

Abstract: Carbon lights up: A facile chemical method yields multicolor photoluminescent carbon dots derived from polymer/silica nanocomposites, which were prepared using surfactant-modified silica spheres as carriers and resols (phenol/formaldehyde resins) as carbon precursor (see picture). The surface-passivated carbon dots show good biocompatibility as potential bioimaging agents offering nanometer-scale resolution.

Surface–plasmon microscopy

Abstract: The imaging of low-contrast samples is a challenging task for optical measuring techniques, especially if high lateral resolution is also required. For example, a heterogeneously organized lipid monolayer transferred from the water surface to a solid substrate1 still needs an additional contrast enhancement mechanism (the solubility difference for a fluorescing chromophore incorporated between the fluid and the crystalline domains of the monolayer) to be visualized by fluorescence microscopy. The mere thickness or index contrast between the different regions is not sufficient to use either phase contrast or Nomarsky microscopy2 or the more recently developed Isoscope ellipsometer3. Here we describe a new microscope technique—surface plasmon microscopy (SPM)— which offers superior contrast without loss of spatial resolution by using plasmon surface polariton (PSP) fields instead of normal light as the illumination source. Such electromagnetic modes travel along a metal–dielectric interface as a bound, non-radiative surface wave, with its field amplitudes decaying exponentially perpen-dicular to the interface. Although photons can be converted into PSPs by means of a plasmon coupler (a grating or a prism in many cases) this 'light' differs considerably from plane electromagneticwaves4. PSPs are characterized by first, a pronounced disper-sion (energy and momentum are not linearly related by the speed of light); and second, a field intensity that is concentrated at the interface and strongly enhanced there. Some of these properties make these modes a sensitive measure of interfaces and ultrathin films. If plasmon surface polariton fields are used to illuminate interfacial structures in light microscopy, high contrast without loss of spatial resolution can be obtained owing to the high sensitivity of the plasmon resonance coupling to (for example) small optical thickness variations of thin dielectric coatings.

Composition-tunable ZnxCd1-xSe nanocrystals with high luminescence and stability

Abstract: High-quality ZnxCd1-xSe nanocrystals have been successfully prepared at high temperature by incorporating stoichiometric amounts of Zn and Se into pre-prepared CdSe nanocrystals. With increasing Zn content, a composition-tunable emission across most of the visible spectrum has been demonstrated by a systematic blue-shift in emission wavelength. The photoluminescence (PL) properties for the obtained ZnxCd1-xSe nanocrystals (PL efficiency of 70−85%, fwhm = 22−30 nm) are comparable to those for the best reported CdSe-based QDs. In particular, they also have good PL properties in the blue spectral range. Moreover, the alloy nanocrystals can retain their high luminescence (PL efficiency of over 40%) when dispersed in aqueous solutions and maintain a symmetric peak shape and spectral position under rigorous experimental conditions. A rapid alloying process was observed at a temperature higher than “alloying point”. The mechanism of the high luminescence efficiency and stability of ZnxCd1-xSe nanocrystals is exp...

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These