Sauces and dressings: a review of properties and applications.

This comprehensive review of sauces and salad dressings covers the literature over the last decade with respect to physical and chemical properties and the applications of these products. As such, texturizing and structural systems (especially hydrocolloids) are described in detail and the application of polysaccharide thickeners as texture providers is described. Microbiological aspects of sauces are covered with relevant sections discussing the factors affecting microbiological activity and microbial spoilage and/or enhancement of a range of sauces. In addition, the use of carbohydrates and proteins as emulsifiers in many sauces is described. Quality aspects are given prominence in this review with sections being devoted to rheological and textural properties, chromatographic approaches and sensory aspects. Healthy sauces such as those having low sodium, reduced fat and cholesterol or containing inulin or microcrystalline cellulose are reviewed. Finally, for various sections the trends of the main findings as well as suggestions for future research are presented.

Interaction of HIV RNA with peptides detected by acoustic shear wave sensor operated in an on-line format.

Acoustic wave sensors are now widely used in various clinical applications because they allow real-time data to be rapidly obtained. In this chapter we describe the use of the thickness shear mode (TSM) acoustic wave sensor to study the interaction between the transactivation responsive region (TAR) of the HIV-1 mRNA and short peptides derived from the regulatory Tat protein as well as with two inhibitor molecules, namely neomycin and streptomycin. The interaction between the TAR-Tat system is a target for the development of antiviral drugs.

Interaction of HIV RNA with peptides detected by acoustic shear wave sensor operated in an on-line format.

Acoustic wave sensors are now widely used in various clinical applications because they allow real-time data to be rapidly obtained. In this chapter we describe the use of the thickness shear mode (TSM) acoustic wave sensor to study the interaction between the transactivation responsive region (TAR) of the HIV-1 mRNA and short peptides derived from the regulatory Tat protein as well as with two inhibitor molecules, namely neomycin and streptomycin. The interaction between the TAR-Tat system is a target for the development of antiviral drugs.

Pharmaceutical counterfeiting.

Pharmaceutical counterfeiting is becoming a serious problem both in developed and developing countries. This paper considers the extent of the problem and provides several examples of drugs which have been counterfeited. Additionally, the effects of counterfeit products on consumers, health care providers, drug manufacturers and governments are discussed. Several of the currently used methods of detection are described and these include near-infrared spectroscopy, Raman spectroscopy, isotopic characterization, tensiography, chromatographic and mass spectrometric approaches. Finally, anti-counterfeiting measures such as the use of holograms, tracers and taggants and electronic tracking are summarized.

Biosensors for the detection of bacteria.

This review will consider the role of biosensors towards the detection of infectious bacteria, although non-infectious ones will be considered where necessary. Recently, there has been a heightened interest in developing rapid and reliable methods of detection. This is especially true for detection of organisms involved in bioterrorism, food poisoning, and clinical problems such as antibiotic resistance. Biosensors can assist in achieving these goals, and sensors using several of the different types of transduction modes are discussed: electrochemical, high frequency (surface acoustic wave), and optical. The paper concludes with a discussion of three areas that may make a great impact in the next few years: integrated (lab-on-a-chip) systems, molecular beacons, and aptamers.

Screening of inhibitors using enzymes entrapped in sol-gel-derived materials.

In recent years, a number of new methods have been reported that make use of immobilized enzymes either on microarrays or in bioaffinity columns for high-throughput screening of compound libraries. A key question that arises in such methods is whether immobilization may alter the intrinsic catalytic and inhibition constants of the enzyme. Herein, we examine how immobilization within sol-gel-derived materials affects the catalytic constant (kcat), Michaelis constant (KM), and inhibition constant (KI) of the clinically relevant enzymes Factor Xa, dihydrofolate reductase, cyclooxygenase-2, and gamma-glutamyl transpeptidase. These enzymes were encapsulated into sol-gel-derived glasses produced from either tetraethyl orthosilicate (TEOS) or the newly developed silica precursor diglyceryl silane (DGS). It was found that the catalytic efficiency and long-term stability of all enzymes were improved upon entrapment into DGS-derived materials relative to entrapment in TEOS-based glasses, likely owing to the liberation of the biocompatible reagent glycerol from DGS. The KM values of enzymes entrapped in DGS-derived materials were typically higher than those in solution, whereas upon entrapment, kcat values were generally lowered by a factor of 1.5-7 relative to the value in solution, indicating that substrate turnover was limited by partitioning effects or diffusion through the silica matrix. Nonetheless, the apparent KI value for the entrapped enzyme was in most cases within error of the value in solution, and even in the worst case, the values differed by no more than a factor of 3. The implications of these findings for high-throughput screening are discussed.

MEMS technology in analytical chemistry.

Microelectromechanical systems promise to revolutionize nearly every product category by bringing together silicon-based microelectronics with micromachining technology, moving us closer towards the realization of complete systems-on-a-chip. Anil Deisingh talks us through the basics of MEMS technology and the growing role of these new "micromachines" in analytical chemistry applications.