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.

The Origins of Academic Chemical Engineering

Abstract: The origins of chemical engineering can be linked to the industrial revolution of the 18th and 19th century in Europe and the United States (1–4) and the sociopolitical changes following the 1848 revolution in France and Germany (5–6). No doubt one can claim that chemical engineering was practiced even by the ancient Greeks and Romans when they were making soap or wine, or treating ores in Lavrion or Sicily.

Compositions de reseaux de polymeres et procedes associes

Abstract: L'invention concerne des reseaux de polymeres biomimetiques qui comportent un reseau d'heteropolymeres pourvus d'une cavite qui possede une affinite selective pour une fraction donnee. Par ailleurs, l'invention concerne des procedes de fabrication de reseaux polymeres biomimetiques ainsi que des procedes d'utilisation de reseaux polymeres biomimetiques.

Use of complexation hydrogels for oral delivery of chemotherapeutic agents

Abstract: Carriers were synthesized to target delivery of a chemotherapeutic agent, bleomycin, to the upper small intestine. Release of bleomycin was initiated in response to hydrogen bonding complexation/decomplexation associated with the pH shift when entering the upper small intestine from the stomach. Hydrogel nanospheres composed of methacrylic acid (MAA) and poly(ethylene glycol) (PEG) [P(MAA-g-EG)] were loaded with bleomycin. Loading of bleomycin was performed by in situ polymerization and release of bleomycin from the nanospheres was measured by UV spectrophotometry. Results showed that bleomycin release from the nanospheres was responsive to the pH of the environment surrounding the nanospheres. In addition to pH-responsive release of bleomycin, the hydrogel nanospheres were also able to enhance drug permeability through an in vitro model of the intestinal epithelium. Increasing the permeability of the intestinal epithelium could aid the transport of bleomycin from the lumen of the small intestine out into the bloodstream.

Influence of extracellular cues of hydrogel biomaterials on stem cell fate

Abstract: Abstract Tissue engineering is a multidisciplinary field that focuses on creating functional tissue through the combination of biomimetic scaffolds, a cell source, and biochemical/physiochemical cues. Stem cells are often used as the cell source due to their multipotent properties and autologous sourcing; however, the combination of physical and chemical cues that regulate their behavior creates challenges in reproducibly directing them to a specific fate. Hydrogel biomaterials are widely explored as tissue scaffolds due to their innate biomimetic properties and tailorability. For these constructs to be successful, properties such as surface chemistry and spatial configuration, stiffness, and degradability of the biomaterial used for the scaffold framework should be analogous to the natural environment of the tissue they are repairing/replacing. This is imperative, as cues from the surrounding extracellular matrix (ECM) influence stem cell behavior and direct cell differentiation to a specific lineage. Hydrogels offer great promise as tools to control stem cell fate, as researchers can modulate the degradation rates, mechanical properties, swelling behavior, and chemical properties of the biomaterial scaffold to mimic the instructive cues of the native ECM. Discussion of the advantages and challenges of utilizing hydrogel biomaterials as the basis of tissue scaffolds is reviewed herein, as well as specific examples of hydrogels in tissue engineering and advances in hydrogel research to achieve desired cell phenotypes.

Structure and Solute Size Exclusion of Poly(methacrylic acid)/Poly(N-isopropyl acrylamide) Interpenetrating Polymeric Networks

Abstract: Interpenetrating polymer networks of poly(methacrylic acid) (PMAA)/poly(N-isopropyl acrylamide) (PNIPAAm)were prepared. Differential scanning calorimetry (DSC) were conducted on PMAA/PNIPAAm IPN hydrogels swollen at different pH values. DSC experiments were conducted on preswollen hydrogel samples, with a total weight of approximately 15 mg. The IPN hydrogels were cut into 10-mm-diameter disks and dried under vacuum at 37°C. The ionic strength also plays an important role in the IPN swelling behavior. Hydrogels are hydrophilic three-dimensional networks formed by Hcrosslinked polymer chains, entanglements, or crystalline regions. From theophylline to FITC-Dextran, the permeability decreases, which is an indication of the size exclusion behavior in the IPN membrane: at the same gel swollen state, the IPNs show higher permeability for the smaller solutes. At temperatures lower than 32°C, the gel is swollen, whereas at temperatures higher than 32°C, the gel dehydrates to the collapsed state due to the breakdown of the delicate hydrophilic/hydrophobic balance in the network structure.

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.