Krister Holmberg

Bio: Krister Holmberg is an academic researcher from Chalmers University of Technology. The author has contributed to research in topics: Pulmonary surfactant & Microemulsion. The author has an hindex of 56, co-authored 315 publications receiving 11466 citations. Previous affiliations of Krister Holmberg include Pierre-and-Marie-Curie University.

Lipases at interfaces : a review

Abstract: Lipases are acyl hydrolases that play a key role in fat digestion by cleaving long-chain triglycerides into polar lipids Due to an opposite polarity between the enzyme (hydrophilic) and their substrates (lipophilic), lipase reaction occurs at the interface between the aqueous and the oil phases Hence, interfaces are the key spots for lipase biocatalysis and an appropriate site for modulating lipolysis Surprisingly enough, knowledge about the effects of the interfacial composition on lipase catalysis is still limited and only described by the term "interfacial quality" Recent systematic studies based on a biophysical approach allowed for the first time to show the effects of the interfacial microenvironment on lipase catalysis These studies demonstrate that lipase activity as a function of interfacial composition is more attributed to substrate inaccessibility rather than to enzyme denaturation or inactivation, as it is often hypothesized A detailed analysis of the interfacial properties of all compounds involved in triglyceride digestion revealed that lipolysis is a self-regulated reaction This feedback mechanism can be explored as a new avenue to control lipase catalysis To substantiate this hypothesis, oil hydrolysis in a model gastro-intestinal system was performed, which can be seen as an interfacial engineering approach to enzyme reactivity control The presented characterization of the interfacial composition and its consequences provide a new approach for the understanding of lipase reactions at interfaces with direct impact on biotechnological and health care applications

Handbook of applied surface and colloid chemistry

Abstract: Contributors List. Foreword. Preface. Part 1: Surface Chemistry in Important Technologies. Surface Chemistry in Pharmacy (Martin Malmsten). Surface Chemistry in Food and Feed (Bjorn Bergenstahl). Surface Chemistry in Detergency (Wolfgang von Rybinski). Surface Chemistry in Agriculture (Tharwat F. Tadros). Surface and Colloid Chemistry in Photographic Technology (John Texter). Surface Chemistry in Paints (Krister Holmberg). Surface Chemistry in Paper (Fredrick Tiberg et al). Surface Chemistry in the Polymerization of Emulsion (Klaus Tauer). Colloidal Processing of Ceramics (Lennart Bergstrom). Surface Chemistry in Disperson, Flocculation and Flotation (Brij M. Moudgil eet al). Surface Chemistry in the Petroleum Industry (James R Kanicky et al). Part 2: Surfactants. Anionic Surfactants (Antje Schmalstieg and Guenther W. Wasow). Nonionic Surfactants (Michael F. Cox). Cationic Surfactants (Dale S. Steichen). Zwitterionic and Amphoteric Surfactants (David T. Floyd et al). Polymeric Surfactants (Tharwat F. Tadros). Speciality Surfactants (Krister Holmberg). Hydrotropes (Anna Matero). Physico-Chemical Properties of Surfactants (Bjorn Lindman). Surfactant-Polymer Systems (Bjorn Lindman). Surfactants Liquid Crystals (Syed Hussan et al). Environmental Aspects of Surfactants (Lothar Huber and Lutz Nitschke). Molecular Dynamics Computer Simulations of Surfactants (Hubert Kuhn and Heinz Rehage). Part 3: Colloidal Systems and Layer Structures at Surfaces. Solid Dispersons (Staffan Wall). Foams and Foaming (Robert J. Pugh). Vesicles (Brian H. Robinson and Madeleine Rogerson). Microemulsions (Klaus Wormuth et al). Langmuir-Blodgett Films (Hubert Motschmann and Helmuth Mohwald). Self-Assembling Monolayers: Alkaline Thiols on Gold (Dennis S. Everhart). Part 4: Phenomena in Surface Chemistry. Wetting, Spreading and Penetration (Karina Grundke). Foam Breaking in Aqueous Systems (Robert J. Pugh). Solubilization (Thomas Zemb and Fabienne Testard). Rheological Effects in Surfactant Phases (Heinz Hoffmann and Werner Ulbricht). Part 5: Analysis and Characterization in Surface Chemistry Measuring Equilibrium Surface Tensions (Michael Mulqueen and Paul D.T. Huibers). Measuring Dynamic Surface Tensions (Reinhard Miller et al). Determining Critical Micelle Concentration (Alexander Patist). Measuring Contact Angle (C.N. Catherine Lam et al). Measuring Micelle Size and Shape (Magnus Nyden). Identification of Lyotropic Liquid Crystalline Mesophases (Stephen T. Hyde). Characterization of Microemulsion Structure (Ulf Olsson). Measuring Particle Size by Light Scattering (Michael Borkovec). Measurement of Electrokinetic Phenomena in Surface Chemistry (Norman L. Burns). Measuring Interactions between Surfaces (Per M Claesson and Mark W. Rutland). Measuring the Forces and Stability of Thin-Liquid Films (Vance Bergeon). Measuring Adsorption (Bengt Kronberg). Index.

Water-in-diesel emulsions and related systems.

Abstract: Water-in-diesel emulsions are fuels for regular diesel engines. The advantages of an emulsion fuel are reductions in the emissions of nitrogen oxides and particulate matters, which are both health hazardous, and reduction in fuel consumption due to better burning efficiency. An important aspect is that diesel emulsions can be used without engine modifications. This review presents the influence of water on the emissions and on the combustion efficiency. Whereas there is a decrease in emissions of nitrogen oxides and particulate matters, there is an increase in the emissions of hydrocarbons and carbon monoxide with increasing water content of the emulsion. The combustion efficiency is improved when water is emulsified with diesel. This is a consequence of the microexplosions, which facilitate atomization of the fuel. The review also covers related fuels, such as diesel-in-water-in-diesel emulsions, i.e., double emulsions, water-in-diesel microemulsions, and water-in-vegetable oil emulsions, i.e., biodiesel emulsions. A brief overview of other types of alternative fuels is also included.

Surfactants and Polymers in Aqueous Solution, 2nd ed.

Abstract: Many industrial formulations such as detergents, paints, foodstuff and cosmetics contain both surfactants and polymers and their interaction govern many of the properties. This book is unique in that it discusses the solution chemistry of both surfactants and polymers and also the interactions between the two. The book, which is based on successful courses given by the authors since 1992, is a revised and extended version of the first edition that became a market success with six reprints since 1998. Surfactants and Polymers in Aqueous Solution is broad in scope, providing both theoretical insights and practical help for those active in the area.

Protein-rejecting ability of surface-bound dextran in end-on and side-on configurations: comparison to PEG.

Abstract: There is much interest in attaching polyethylene glycol (PEG) and other hydrophilic, neutral polymers to surfaces to reduce the extent of protein and cell adsorption. Interestingly, these same surface-bound polymers are effective in masking surface charge and reducing electrokinetic effects such as particle electrophoretic mobility, streaming potential, and electroosmosis. It is apparent that similar molecular properties are responsible for both protein and cell rejection and reduction of electrokinetic effects. In this work we compared the fibrinogen-rejecting ability and the effect on electrophoretic mobility of three polymer coatings bound to polystyrene. The three polymers were side-bound dextran, end-bound dextran, and end-bound PEG. The results of these measurements were used to elucidate the importance of polymer packing density and polymer layer thickness on protein adsorption and reduction of electrokinetic effects. Protein adsorption appears not to be sensitive to polymer layer thickness or the presence of dilute polymer tails in a surface coating, while electrokinetic effects are. Protein adsorption is, however, very sensitive to the availability of exposed surface. Finally, the unique effectiveness of PEG is apparent in this research as in previous studies. © 1995 John Wiley & Sons, Inc.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

Chemistry and properties of nanocrystals of different shapes.

Abstract: The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

Synthesis and surface engineering of iron oxide nanoparticles for biomedical applications

Abstract: Superparamagnetic iron oxide nanoparticles (SPION) with appropriate surface chemistry have been widely used experimentally for numerous in vivo applications such as magnetic resonance imaging contrast enhancement, tissue repair, immunoassay, detoxification of biological fluids, hyperthermia, drug delivery and in cell separation, etc. All these biomedical and bioengineering applications require that these nanoparticles have high magnetization values and size smaller than 100 nm with overall narrow particle size distribution, so that the particles have uniform physical and chemical properties. In addition, these applications need special surface coating of the magnetic particles, which has to be not only non-toxic and biocompatible but also allow a targetable delivery with particle localization in a specific area. To this end, most work in this field has been done in improving the biocompatibility of the materials, but only a few scientific investigations and developments have been carried out in improving the quality of magnetic particles, their size distribution, their shape and surface in addition to characterizing them to get a protocol for the quality control of these particles. Nature of surface coatings and their subsequent geometric arrangement on the nanoparticles determine not only the overall size of the colloid but also play a significant role in biokinetics and biodistribution of nanoparticles in the body. The types of specific coating, or derivatization, for these nanoparticles depend on the end application and should be chosen by keeping a particular application in mind, whether it be aimed at inflammation response or anti-cancer agents. Magnetic nanoparticles can bind to drugs, proteins, enzymes, antibodies, or nucleotides and can be directed to an organ, tissue, or tumour using an external magnetic field or can be heated in alternating magnetic fields for use in hyperthermia. This review discusses the synthetic chemistry, fluid stabilization and surface modification of superparamagnetic iron oxide nanoparticles, as well as their use for above biomedical applications.