Nicholas A. Peppas

Bio: Nicholas A. Peppas is an academic researcher from University of Texas at Austin. The author has contributed to research in topics: Self-healing hydrogels & Drug delivery. The author has an hindex of 141, co-authored 825 publications receiving 90533 citations. Previous affiliations of Nicholas A. Peppas include National Technical University & University of Texas System.

Self- and mutual-diffusion coefficients in the dodecane/polystyrene system

Abstract: The self-diffusion coefficient of dodecane in cross-linked polystyrene was measured using pulsed gradient spin echo nuclear magnetic resonance (PGSE–NMR) spectroscopy. The concentration and temperature dependence of the diffusion coefficient was analyzed by the Fujita and Vrentas–Duda models. Parameters describing the Fujita model were determined from fitting of diffusion data to the PVT behavior of the system. Parameters describing the Vrentas–Duda model were determined from the analysis of the viscosity of dodecane, the viscoelastic relaxation properties, and the glass transition temperature of polystyrene as well as from the diffusion coefficient of the system, measured from independent experiments. Both the Fujita and Vrentas–Duda models described well the concentration and temperature dependence of the diffusion coefficient. Mutual diffusion coefficients were determined from these results. © 1994 John Wiley & Sons, Inc.

Intelligent, responsive and theranostic hydrogel systems for controlled delivery of therapeutics

Abstract: Hydrogels are hydrophilic polymers that have been crosslinked to form a three-dimensional polymer matrix as shown. Under the correct environmental conditions, these materials can imbibe significant amounts of water, often over two orders of magnitude more water than polymer by weight. Due to the large water content, hydrogels are currently the synthetic materials that most resemble living tissue. These properties help make hydrogels ideal for use in tissue engineering, drug delivery, surface coatings, contact lenses, wound dressings, and even polluted water treatment. Swollen crosslinked networks and hydrogels have been influential in the improvement of polymeric systems for controlled release of a wide variety of therapeutic agents. These materials are attractive as carriers for transmucosal and intracellular drug delivery because of their inherent biocompatibility, tunable physicochemical properties, basic synthesis, and ability to be physiologically responsive.

Quantitative Measurement of Interdiffusion at Polymer–Polymer Interfaces with TEM/EDS and EELS

Abstract: Transmission electron microscopy and energy dispersive spectroscopy (TEM/EDS) were used to map the concentration profile at the interface of a poly(vinyl chloride) and poly(methyl methacrylate) bilayer. Thin sections in the order of 800 A were cut using an ultramicrotome, examined with TEM, and the concentration profile was mapped with EDS. The intensity of fluorescence X-rays was adjusted for sample thickness variation by measuring the relative thickness across the interface with electron energy-loss spectroscopy (EELS). The interfacial thickness of the bilayer after 6 h at 120°C was 1.5 μm, whereas the interdiffusion coefficient was determined as 8.0 X 10 -14 cm 2 /s. © 1995 John Wiley & Sons, Inc.

Vecteurs de médicaments innovants et « intelligents » : leurs applications pharmaceutiques

Abstract: Resume Au cours des trente dernieres annees, notre laboratoire a developpe des systemes innovants a base de biomateriaux « intelligents » pour l′administration des medicaments. Ces systemes ont ete utilises pour la conception de nouvelles formes pharmaceutiques destinees a l’administration orale de l’insuline ou d’autres proteines a usage therapeutique ainsi que pour la detection de substances biologiques endogenes avec liberation de principes actifs appropries. Cet article decrit la preparation et les applications possibles de tels systemes d’administration.

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。

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

Harrison's Principles of Internal Medicine

Abstract: The 11th edition of Harrison's Principles of Internal Medicine welcomes Anthony Fauci to its editorial staff, in addition to more than 85 new contributors. While the organization of the book is similar to previous editions, major emphasis has been placed on disorders that affect multiple organ systems. Important advances in genetics, immunology, and oncology are emphasized. Many chapters of the book have been rewritten and describe major advances in internal medicine. Subjects that received only a paragraph or two of attention in previous editions are now covered in entire chapters. Among the chapters that have been extensively revised are the chapters on infections in the compromised host, on skin rashes in infections, on many of the viral infections, including cytomegalovirus and Epstein-Barr virus, on sexually transmitted diseases, on diabetes mellitus, on disorders of bone and mineral metabolism, and on lymphadenopathy and splenomegaly. The major revisions in these chapters and many

Understanding biophysicochemical interactions at the nano–bio interface

Abstract: Rapid growth in nanotechnology is increasing the likelihood of engineered nanomaterials coming into contact with humans and the environment. Nanoparticles interacting with proteins, membranes, cells, DNA and organelles establish a series of nanoparticle/biological interfaces that depend on colloidal forces as well as dynamic biophysicochemical interactions. These interactions lead to the formation of protein coronas, particle wrapping, intracellular uptake and biocatalytic processes that could have biocompatible or bioadverse outcomes. For their part, the biomolecules may induce phase transformations, free energy releases, restructuring and dissolution at the nanomaterial surface. Probing these various interfaces allows the development of predictive relationships between structure and activity that are determined by nanomaterial properties such as size, shape, surface chemistry, roughness and surface coatings. This knowledge is important from the perspective of safe use of nanomaterials.