A historical overview

Finally, we mention a new development in treating the hydrodynamic properties of elastic filaments. A recently introduced partide-based mesoscopic simulation method, called muMpartide collision dynamics [65, 66], was used to study the hydrodynamic interaction and cooperation of sperm cells embedded in a two-dimensional fluid [67]. 

The foundations of modem chemical bonding theory were laid in 1916-1920 by G.N. Lewis and I. Langmuir, who suggested that ionic species were formed by electron transfer while electron sharing was important in covalent molecules. In some cases, it was suggested that the shared electrons in a bond were provided by one of the atoms but that once the bond (sometimes called a coordinate bond) is formed, it is indistinguishable from a normal covalent bond. 

In a covalent species, electrons are shared betwerai atoms. In an ionic species, one or more electrons are transferred between atoms to form ions. 

Modem views of atomic structure are, as we have seen, based largely on the applications of wave mechanics to atomic systems. Modem views of molecular structure are based on applying wave mechanics to molecules such studies provide answers as to how and why atoms combine. The Schrodinger equation can be written to describe the behaviour of electrons in molecules, but it can be solved only approximately. Two methods of doing this are the valence bond approach, developed by Heitler and Pauling, and the molecular orbital approach associated with Hxmd and MuUiken  

Although familiarity with both VB and MO concepts is necessary, it is often the case that a given situation is more conveniently approached by using one or other of these models. We begin with the ccaiceptually simple approach of Lewis for representing the bonding in covalent molecules. 

Lewis presented a simple, but useful, method of describing the arrangement of valence electrons in molecules. The approach uses dots (or dots and crosses) to represent the number of valence electrons, and the nuclei are indicated by appropriate elemental symbols. A basic premise of the theory is that electrons in a molecule should be paired the presence of a single (odd) electron indicates that the species is a radical. 

In a covalent species, electrons are shared between atoms. 

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Vedam K 1998 Spectroscopic ellipsometry a historical overview Thin Solid Films 313/314 1-9... 

The role of the Bell Labs metallurgists in the creation of the early transistors was clearly set out in a historical overview by the then director of the Materials Research Laboratory at Bell Labs, Scaflf (1970). 

Aitken A (2006) 14-3-3 Proteins a historic overview. Semin Cancer Biol 16 162-172... 

Trumper, R. (2003). The physics laboratory A historical overview and future perspectives. Science... 

An ELN may be viewed as an enterprise software application that enables scientists to record chemical and biological data and to search and share their work with their colleagues, who can be on the other side of the globe. This simplistic definition is not sufficient to portray what real-world ELN applications do and how they have improved the productivity of scientists, engineers, and innovators. Therefore, a historical overview is useful to help understand the broader usefulness of ELN applications. 

A. Historical Overview of Triatomic Rare Gas-Dihalogen Interactions... 

Schwerdtfeger, P. and Thierfelder, C. (2006) Relativistic Quantum Chemistry -A Historical Overview, in Trends and Perspectives in Modem Computational Science, Vol. 6 Lecture Series on Computer and Computational Sciences (eds G. Maroulis and T. Simos), Brill Academic Publishers, Leiden, The Netherlands, pp. 453-460. 

During the Golden Age of Islam (7th through the 17th century) Muslim philosophers and poets, artists and scientists, princes and laborers created a unique culture that has influenced societies on every continent. Here documentary writer Howard Turner offers a fully illustrated, highly accessible introduction to the scientific achievements of medieval Islam. Howard Turner opens with a historical overview of the spread of Islamic civilization from the Arabian peninsula eastward to India and westward across northern... 

This volume of Topics in Stereochemistry could not be complete without hearing about ferroelectric liquid crystals, where chirality is the essential element behind the wide interest in this mesogenic state. In Chapter 8, Walba, a pioneering contributor to this area, provides a historical overview of the earlier key developments in this field and leads us to the discovery of the unique banana phases. This discussion is followed by a view of the most recent results, which involve, among others, the directed design of chiral ferroelectric banana phases, which display spontaneous polar symmetry breaking in a smectic liquid crystal. 

Introductory Chapter 1 provides a historical overview of molecular sieve materials. Chapter 2 covers the definition of a zeolite and describes their basic and composite building units and how they are linked in zeolite frameworks. It defines pores, channels, cages and cavities and it gives references for finding detailed... 

Mechoulam R, Hanus L, A historical overview of chemical research on cannabi-noids, Chem Phys Lipids 108 1-13, 2000. 

Petersen F. (2005) Natural products research at Novartis Pharmaceuticals — A historical overview. In Drug Discovery from Natural Products — 85 Years of Natural Products Research at Novartis, pp. 1-13. NIBR Global Communications, Cambridge, USA. 

Evolution of Liquid Chromatography A Historical Overview L. S. Ettre... 

W. Paul, High Pressure in Semiconductor Physics A Historical Overview N. E. Christensen, Electronic Structure Calculations for Semiconductors under Pressure R. J. Neimes and M. I. McMahon, Structural Transitions in the Group IV, III-V and II-VI Semiconductors Under Pressure... 

Borreliosis is a disease that frequently and typically affects both the central and peripheral nervous systems (Table 13 for a historical overview, see Table 14). Owing to the frequent occurrence in our area, it is possible to observe highly variable clinical manifestations as well as different types of pathological appearances in cerebrospinal fluid. Current methods used in neuroborreliosis diagnosis include the evaluation of specific antibodies IgM, IgG detected by ELISA, Western blot, and PCR. 

Bartus RT, Dean RL, Pontecorvo MJ, et al The chohnergic hypothesis a historical overview, current perspectives, and future directions. Ann N Y Acad Sci 444 332-358, 1985... 

In this chapter, we will define biotechnology from the perspective of pharmaceuticals and follow this with a historical overview of pharmaceutical biotechnology and a discussion of how macromolecules are named and used as therapeutic agents. 

Ecobichon DJ Our changing perspectives on benefits and risks of pesticides A historical overview. Neurotoxicology 2000 21 211. [PMID 10794402]... 

Heller, J. (1990). Development of poly(ortho esters)—a historical overview. Biomaierials, 11, 659-665. 

The object of this chapter is to provide the reader with a qualitative understanding of hydrate phase equilibrium. Such an understanding implies a historical overview, which also provides successive approximations to hydrate phase equilibrium in terms of accuracy. The accuracy of three-phase prediction is given below in the order of increasing accuracy ... 

Readers of different backgrounds will wish to follow different paths through the chapters. Both the engineer and the researcher may wish to read Chapter 1 that provides a historical overview of clathrate hydrates. One cannot deal with hydrates without some knowledge of the all-important crystal structures provided in Chapter 2. Chapter 3 on hydrate kinetics gives the current picture ofhydrate time-dependence to supplement the time-independent phase equilibria in Chapter 4, the last chapter that should be of common interest to both the engineer and the... 

L. S. Ettre, Evolution of liquid chromatography a historical overview. In High-Performance Liquid Chromatography (C. Horvath, ed.), Academic Press, New York, 1980, p. 54. 

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