Research, continuing

One of the most commonly used constructs is a model. A model is a simple way of describing and predicting scientific results, which is known to be an incorrect or incomplete description. Models might be simple mathematical descriptions or completely nonmathematical. Models are very useful because they allow us to predict and understand phenomena without the work of performing the complex mathematical manipulations dictated by a rigorous theory. Experienced researchers continue to use models that were taught to them in high school and freshmen chemistry courses. However, they also realize that there will always be exceptions to the rules of these models. 

Propylene oxide [75-56-9] (methyloxirane, 1,2-epoxypropane) is a significant organic chemical used primarily as a reaction intermediate for production of polyether polyols, propylene glycol, alkanolamines (qv), glycol ethers, and many other useful products (see Glycols). Propylene oxide was first prepared in 1861 by Oser and first polymerized by Levene and Walti in 1927 (1). Propylene oxide is manufactured by two basic processes the traditional chlorohydrin process (see Chlorohydrins) and the hydroperoxide process, where either / fZ-butanol (see Butyl alcohols) or styrene (qv) is a co-product. Research continues in an effort to develop a direct oxidation process to be used commercially. 

Sohd-state multi-element detector arrays in the focal planes of simple grating monochromators can simultaneously monitor several absorption features. These devices were first used for uv—vis spectroscopy. Infrared coverage is limited (see Table 3), but research continues to extend the response to longer wavelengths. Less expensive nir array detectors have been appHed to on-line process instmmentation (125) (see Photodetectors). 

Areas of Continued Research. Research continues in many academic and pharmaceutical laboratories throughout the wodd with the objective of improving oral contraceptives and better understanding their pharmacological and clinical actions. 

Special Active Agents. Toothpastes are vehicles for agents that provide special therapeutic and nontherapeutic effects. The scope of these agents has increased dramatically since the 1960s and research continues. 

Research continues in both industi y and government to find ways to innovate and improve air conditioning systems. For example, ASHRAE maintains an ongoing research program covering energy conseiva-... 

How deeply one wishes to query the mechanism depends on the detail sought. In one sense, the quest is never done a finer and finer resolution of the mechanism may be obtained with further study. For example, the rates and mechanisms of electron transfer reactions have been studied experimentally and theoretically since the 1950s. but the research continues unabated as issues of ever finer detail and broader import are examined. The same can be said of other reactions—nucleophilic substitution, hydrolysis, etc. 

As medical researchers continue to explore the therapeutic properties of interferons, chemical engineers will continue to provide the expertise needed to make available the quantities of these molecules necessary for clinical evaluation. 

In the traditional lithography approach, researchers continued to consider the idea that modem STM (scanning tunnel Microscopy) could be the proper tool for the formation of two-junction systems when working with very small particles. This consideration had related the studies of single-electron phenomena to the concept of quantum dots (Glazman and Shechter 1989). 

The record for the highest superconducting temperature in the year 2004 is 138 K, held by a nonstoichiometric ceramic oxide, HgQ g Tig 2 Ba2 Ca2 C1I3 Og 33. This is still far below room temperature, but research continues. 

The most desirable property of polycarbonates is their high ductility on impact, relative to other engineering polymers in the unmodified state. There is no consensus on the mechanism of ductility researchers continue to explore this behavior through molecular dynamics studies of chain segment motion during the formation of crazes and propagation of the failure. 

As research continues into the field of siderophore production and iron uptake, the knowledge gained will be invaluable to the development of medical treatments for bacterial infection,... 

Biomedical research continues to broaden our understanding of the molecular mechanisms underlining both health and disease. Research undertaken since the 1950s has pinpointed a host of proteins produced naturally in the body that have obvious therapeutic applications. Examples include the interferons and interleukins (which regulate the immune response), growth factors, such as erythropoietin (EPO which stimulates red blood cell production), and neurotrophic factors (which regulate the development and maintenance of neural tissue). 

Virtually all therapeutic proteins must enter the blood in order to promote a therapeutic effect. Such products must usually be administered parenterally. However, research continues on the development of non-parenteral routes which may prove more convenient, less costly and obtain improved patient compliance. Alternative potential delivery routes include transdermal, nasal, oral and bucal approaches, although most progress to date has been recorded with pulmonary-based delivery systems (Chapter 4). An inhaled insulin product ( Exubera , Chapters 4 and 11) was approved in 2006 for the treatment of type I and II diabetes. 

The operating principles of the reviewed interferometers are well studied. However, by no means these devices are matured. For example, a mode-selective, wavelength-independent and environmental-resistant 3-dB core-cladding mode coupler is yet to be found to construct an ideal CCMI. As technology advances and research continues, we expect that more device structures will be explored and new methods will be investigated to fabricate these devices. Although the applications of these two types of sensors are yet to be explored, it is almost certain that they will find their way into real-world applications in the future. 

On-going studies to improve analytical methods for hexachloroethane and related compounds include the EPA "Master Analytical Scheme" being developed for organic compounds in water (Michael et al. 1988) and the research in supercritical fluid extraction (Lopez-Avila et al. 1991 Wieboldt et al. 1988). Research continues on improving extraction, concentration, and elution techniques, and detection devices (Eichelberger et al. 

As is often the case, after the intense activity of the 1920 s, the investigation of aqueous electrolytes proceeded at a more relaxed pace. But careful and systematic experimental research continued in this area and was summarized by Harned and Owen (2) and by Robinson and Stokes (3) in their excellent monographs. The latter volume contains in the appendix a comprehensive set of tables of the osmotic and activity coefficients of the common inorganic solutes at 25°C and at concentrations up to 6 M in most cases. 

As the pig house odour research continued, it became clear that the one observer procedure is time consuming. Only two odour measurements per day were possible. Futhermore, panel members observed a stress which was caused by the noise of the olfactometers. Therefore it was decided to order a set of three double sniffing port low noise olfacometers at the University of Utrecht. The Psychological Laboratory of this university had some experience in the construction of olfactometers. The flowrate was set at 10 1/min arbitrary. 

Most recent research continues to point to the immediate toxicity of these chemicals, the presence of their metabolites in the urine of the general population (especially children), and their potential long-term impact on reproduction. More generally, the potential neural damage organophosphates may cause. 

Toluene is used more commonly than the other BTXs as a commercial solvent. There are scores of solvent applications, though environmental constraints and health concerns diminish the enthusiasm for these uses. Toluene also is used to make toluene diisocyanate, the precursor to polyurethane foams. Other derivatives include phenol, benzyl alcohol, and benzoic acid. Research continues on ways to use toluene in applications that now require benzene. The hope is that the dealkylation-to-benzene or disproportionation steps can be eliminated. Processes for manufacturing styrene and terephthalic acid—the precursor to polyester fiber—are good, commercial prospects. 

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