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

The Design and Analysis of Experiments

Design and applications of interpenetrating polymer network hydrogels. A review

Removal of heavy metal ions using chitosan and modified chitosan: A review

Hydrogels are hydrophilic, three-dimensional networks that are able to absorb large quantities of water or biological fluids, and thus have the potential to be used as prime candidates for biosensors, drug delivery vectors, and carriers or matrices for cells in tissue engineering. In this critical review article, advantages of the hydrogels that overcome the limitations from other types of biomaterials will be discussed. Hydrogels, depending on their chemical composition, are responsive to various stimuli including heating, pH, light, and chemicals. Two swelling mechanisms will be discussed to give a detailed understanding of how the structure parameters affect swelling properties, followed by the gelation mechanism and mesh size calculation. Hydrogels prepared from natural materials such as polysaccharides and polypeptides, along with different types of synthetic hydrogels from the recent reported literature, will be discussed in detail. Finally, attention will be given to biomedical applications of different kinds of hydrogels including cell culture, self-healing, and drug delivery.

Hydrogels for Biomedical Applications: Their Characteristics and the Mechanisms behind Them

During the past decades, hydrogels have been introduced suitable as novelmaterials for a variety of applications such as biomedical engineering, sanitaryproducts, agriculture, bioseparation, enhanced oil recovery, etc. They havebeen successfully used as superabsorbent materials and in drug delivery, cellencapsulation and tissue repair due to their high water content and consequentbiocompatibility. Considering the fact that water retention in the hydrogels provides asuitable drug diffusion pathway; many hydrogel-based networks have been designedand fabricated as intelligent carriers of drugs. The rate and degree of hydrogel swellingare the most important parameters which control the release patterns of solvents anddrugs from these polymeric networks. Therefore, the precise account of hydrogelbehaviour as well as mathematical description of equilibrium swelling, dimensionalchanges due to solvent uptake, desorption and drug release profiles were the mainobjectives in many investigations. The objective of this manuscript is to give a briefreview on existing mathematical models and theories in the field of hydrogel swellingas well as the description of the drug release mechanism from swelling-controllednetworks. The most important properties of hydrogels relevant to their swellingbehaviour as well as kinetics and thermodynamic of swelling are also presented.

Theoretical Description of Hydrogel Swelling: A Review

Novel pH-sensitive hydrogels based on chitosan, itaconic acid and methacrylic acid were prepared in two steps. Chitosan was first ionically crosslinked with itaconic acid, after which a free radical polymerization and crosslinking of the chitosan/itaconic acid network was performed by adding methacrylic acid and a crosslinker in order to achieve better mechanical properties and tunable swelling. The samples were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, X-ray diffraction, dynamic mechanical analysis and the swelling ratios of the hydrogels at various pH values (2.0–8.0). The hydrogel composition is found to have a great impact on the hydrogel structure, mechanical and thermal properties, morphology and swelling kinetics. The highly porous morphology of the gels is probably connected with the bulky chitosan/itaconic acid network which reduces the degree of crosslinking in the second step of the synthesis due to steric hindrances. The gels demonstrate substantial change in buffer absorbency with change of pH, low for acid buffers and the higher for pH values above 6 where the swelling is considerably slow, thus suggesting their strong candidature for use as oral drug-delivery systems in the lower parts of the gastrointestinal tract and for drugs that require longer release times. Copyright © 2010 Society of Chemical Industry

Melina Kalagasidis Krušić

Papers

Preparation and characterization of pH-sensitive hydrogels based on chitosan, itaconic acid and methacrylic acid

Removal of Cu2+ ions using hydrogels of chitosan, itaconic and methacrylic acid: FTIR, SEM/EDX, AFM, kinetic and equilibrium study

Copolymer hydrogels based on N-isopropylacrylamide and itaconic acid

Edible blend films of pectin and poly(ethylene glycol): Preparation and physico-chemical evaluation

Chitosan microbeads for encapsulation of thyme (Thymus serpyllum L.) polyphenols.