bluuebunny/crossref_metadata_2025 huggingface dataset:
Sugars in chiral synthesis
Authors: David Serge
Published: November 2023

The experiments we are about to describe bring into play chiral reagents constructed from a titanocene (titanium-carbohydrate complex) (Riediker and Duthaler 1989a; Duthaler et al. 1989; Bold et al. 1989; Riediker et al. 1989b). The starting compound is cyclopentadienyltitanium(IV) trichloride, C5H5TiCl3, which is prepared from dichloride (C5H5)iTiC12 by heating with TiC14. This trichloride reacts with 1,2:5,6-di-0-isopropylidene-α-D-glucofuranose (‘diacetone glucose’) in the presence of triethylamine to provide the bis-titanate 8.1. The latter is a crystalline compound, hence its structure could be determined in the solid state. Its form is that of a three-legged piano stool with the cyclopentadiene ring being its seat. The two ligands have completely different orientations with respect to the cyclopentadienyl ring. Because of this, they create a chiral cavity around the titanium atom. A study of the NMR spectra of 8.1 in solution indicates neither inversion at the metal centre nor rapid ligand exchange. This suggests that the conformation in solution is close to the conformation in the crystal.
Chemical transformations and synthesis of oligosaccharides
Authors: David Serge
Published: November 2023

Reducing oligosaccharides have two different hydroxyl functions, namely the alcohol and the hemiacetal. The alcohol functions are divided into two fairly well differentiated categories, primary and secondary. More subtle differences exist between the secondary alcohol functions, depending on their being axial or equatorial, or combined in a vicinal diol, etc. With respect to monosaccharides, there is nothing fundamentally new here and what is known about the chemistry of oligosaccharides relies on corresponding selective reactions.
The biogeography of grebes
Authors: Fjeldså Jon
Published: November 2023

Grebes have a worldwide (cosmopolitan) distribution (Fig. 5.1), but they are poorly represented in tropical lowlands, and are absent from the high arctic (and Antarctic) regions. The strongholds of grebes are in the temperate steppe biomes and forest/steppe transitions, where the majority of wetlands are shallow depressions, often with mineral-rich and slightly alkaline water, promoting high biological production. Grebes are abundant even in the wetlands of some of the high-altitude steppes in Central Asia and South America, to well above 4 000 m as.
Breeding and life history
Authors: Fjeldså Jon
Published: November 2023

Grebes have become independent of firm land by building floating nest platforms and back-brooding their young. Both behaviours are universal in grebes, suggesting that they were well developed before the differentiation of modern species began. However, grebes which nest solitarily in richly vegetated ponds (notably piedbills, dabchicks, and White-tufted Grebes) often return for 2–3 weeks to brood the young on the nest by night and during bad weather, and sometimes even build extra platforms for brooding and loafing. Thus, some variation is seen in the development of back-brooding.
Environmental threats
Authors: Fjeldså Jon
Published: November 2023

Grebes face some of the same threats as northern diving ducks ( Margin ) and loons, such as toxins, oil-spills, and mortality in fishing-nets—but differ from them because of their dependence on shallow wetlands in the best agricultural districts of the world. Within Europe and USA, more than 50% of the wetland area has been lost over the last 100 years.
The family Podicipedidae
Authors: Fjeldså Jon
Published: November 2023

As a general introduction to the now living grebes, their fossil history and evolutionary relationships are reviewed in this section. This includes a phylogenetic analysis not previously published. The newest formal classification of grebes was that by Stored (1979) in Peter’s Checklist of Birds of the World. The majority of fossil grebes are, with the exception of the early forms mentioned on p. 25, discussed in connection with now living genera or species.
GCD sums with applications
Authors: Harman Glyn
Published: November 2023

Asymptotic formulae reduced to GCD sums. Bounds for GCD sums. Extensions to higher dimensions. Applications to the Duffin-Schaeffer problem. A generalization of Khintchine’s theorem. Sums involving common divisors were introduced in one context in the previous chapter. The following result demonstrates how they arise in a related problem.
Radical-Mediated Protein Oxidation
Authors: Davies Michael J , Dean Roger T
Published: November 2023

Protein oxidation by free radicals is thought to play a major role in many oxidative processes within cells, and is implicated in human disease, carcinogenesis, and ageing. This unique and comprehensive volume brings together up-to-date information on the oxidation of amino acids, peptides, and proteins by free radicals and discusses the roles of such processes in biological systems. Topics include: the chemistry of amino acid and protein oxidation; the biochemical consequences of these reactions; the role of protein oxidation in normal physiology; the potential importance of protein oxidation in human health - including ageing, heart disease, cancer, inflammation and neurodegenerative diseases - and the possible prevention of such processes by antioxidants and other protective strategies.
A historical survey of the study of radical-mediated protein oxidation
Authors: Davies Michael J , Dean Roger T
Published: November 2023

We will give here particular emphasis to the studies before 1970, since those published subsequently are more immediately pertinent to the discussions of later chapters, and are also reasonably well represented in the major review articles we have already listed in the Preface. The first publication we have located on radical-mediated amino acid oxidation without the addition of acid is that of Dakin (1906), and it is also the earliest of those referenced in the major reviews of Garrison (1968) and Stadtman (1993). It is worth summarizing the perceptive work it embodies, both as a taste of the openings of a field, and because of its entertaining contrasts with the styles of experiment and presentation we follow today. The paper is in the first volume of the Journal of Biological Chemistry (JBC) now by far the most extensive journal of biochemistry, publishing around 30 000 pages per volume, but then a modest, small-format single volume for the years 1905–6. It is also amusing and impressive to note that Dakin’s follow-up publication 2 years later (Dakin 1908a) was accompanied by a large batch of other single-author publications of his own, taking up roughly half of the volume of JBC! Such relative occupancy would be impossible even for a large group to achieve today.
The pathology of protein oxidation
Authors: Davies Michael J , Dean Roger T
Published: November 2023

We will devote most of this chapter to focusing on a limited number of pathologies in which it has been possible to make some analysis of the importance of protein oxidation. However, we first wish to summarize the occurrence of products of protein oxidation in a range of pathological situations (Table 5.1), to complement the discussion of Chaper 4. Many, but not all, pathologies are accompanied by the presence of oxidized proteins at levels beyond the physiological. The difficulty, as always, is in distinguishing ‘bystander’ oxidation, which is a quite secondary consequence of the pathology, from that which might be important in its progression.
Scandium(III) and yttrium(III)
Authors: Fukuzawa Shin-Ichi
Published: November 2023

According to the inorganic chemistry text book written by Cotton and Wilkinson, scandium is not truly a rare earth element but yttrium and lanthanides are rare earth elements. The stable oxidation state of scandium is trivalent and the ionic radius of scandium (III) is significantly smaller (0.89 Å) than those for any of the rare earth elements (1.0-1.17 Å). Chemical behaviour is intermediate between aluminium and that of lanthanides. Yttrium has a trivalent oxidation state similar to scandium and lanthanide elements and the ionic radius of yttrium (III) (1.04 Å) is close to those of erbium (1.03 A) and holmium (1.04
Zinc-mediated Barbier reactions
Authors: lucre Jean-louis , Sarandeses luis A
Published: November 2023

Among the synthetic accesses to alcohols, the nucleophilic addition of organometallics to carbonyl groups is certainly one of the more versatile and frequently used, and can be achieved by using a Grignard reaction. The paramount importance of the latter has left somewhat in the shade the Barbier reaction, frequently considered as its ‘ancestor’ in all respects. Barbier’s student V. Grignard discovered the two-step procedure to which his name remained attached, as a development of the original one-step condensation between an organic halide, a carbonyl compound, and a metal (Scheme 15.1).1•2 The latter, direct and easy to perform, has a number of advantages.
Countercurrent extraction and supercritical fluid fractionation
Authors: Clifford Tony
Published: November 2023

For extraction from a liquid phase, countercurrent supercritical fluid extraction or supercritical fluid fractionation can be carried out. The liquid phase may be a liquid mixture, or a solution containing solutes which are solid at the extraction temperature, or a slurry of solid particles, such as microbial cells. The advantages of these processes are firstly that they are continuous and secondly that they are more efficient than a batch process, if well designed. Batch extraction is a single operation; countercurrent extraction and fractionation are processes in which there a number of stages or plates; and chromatography, described in the next chapter, has a large number of plates. Thus, in a sense countercurrent extraction and fractionation are intermediate between extraction and chromatography. The separation efficiency and costs of these processes increase in the order of extraction, countercurrent extraction/fractionation, and chromatography. It often makes economic sense to perform countercurrent extraction or fractionation as a preliminary stage to concentrate the compound of interest, before carrying out chromatography to obtain a very pure product.
Reactions of selenium nucleophiles
Authors: Engman Lars , Gupta Vijay
Published: November 2023

Because selenolate ions are highly reactive, soft nucleophiles, they can be used for the introduction of selenium into a variety of organic molecules. The preparative usefulness of these organoselenium compounds often relies on one of several constructive ways to manipulate the resulting carbon-selenium bond. For example. these can include selenoxide eliminations (see Chapter 2). lithium-selenium exchange to form carbanions (see Chapter 7) or homolytic cleavage to generate carbon-centred radicals (see Chapter 9). Nucleophilic selenium compounds are also useful for a number of functional group manipulations. In these stoichiometric or catalytic processes. the nucleophilic organoselenium species are used as reagents for the one-step transformation of selenium-free starting materials into selenium-free products (see Chapter 6).
Oxidations with selenium reagents
Authors: Back Thomas G
Published: November 2023

Selenium dioxide is an oxidizing agent that was one of the earliest selenium reagents to find widespread application in organic synthesis, with early examples dating from the 1930s. Its properties, preparation and synthetic applications have been the subjects of both early1 and more recent2 reviews. Several methods exist for its preparation by the oxidation of elemental selenium, and it is also commercially available. Pure selenium dioxide is a white, crystalline solid, but the reagent sometimes has a pink coloration, probably because of the presence of elemental selenium. It can be purified by sublimation. It has limited solubility in most organic solvents and must generally be used in aqueous or alcohol media. In many applications, the active oxidant is probably selenious acid (H2SeO3), the hydrolysed form of the dioxide. Selenium dioxide is toxic and so must be handled with appropriate care. Although the compound itself is not malodorous, by-products formed during oxidations of organic substrates are often volatile and highly unpleasant.
Selenium extrusion reactions
Authors: Jr Frank S Guziec , Guziec lynn James
Published: November 2023

Extrusion reactions of organoselenium compounds have only recently been recognized as particularly useful synthetic methods for the preparation of extremely strained organic molecules. In many cases the corresponding sulfur-based reactions were originally investigated, but for the most part the use of selenium-containing molecules as substrates led to increased reactivity and therefore greater overall synthetic utility. Extrusion reactions may be defined as chemical transformations in which an atom or molecular fragment Y directly attached to two atoms X and Z is excised from a molecule leading to a product in which X is directly bonded to Z (Equation 10.1).2 Usually the substrate is a heterocycle which can be thermally or photochemically induced to extrude a stable inorganic species (e.g. N2, CO2, S, Se).
The Ecology of the Indonesian Seas
Authors: Tomascik Tomas , Mah Anmarie Janice , Nontji Anugerah , Moosa Mohammad Kasim
Published: November 2023

Located between the Pacific and Indian Oceans, and between the Asian and Australian continents, the seas of the Indonesian Archipelago have a significant role in global weather patterns and oceanic circulation. The dynamic interplay between geological, physical, chemical, and biological processes, past and present, has given rise to one of the most diverse marine regions on the planet. The exceptional marine and coastal ecosystem diversity of the Indonesian archipelago provides hundreds of habitats that support thousands of species. This treasure trove of marine biodiversity has sustained the people of the archipelago for thousands of years. Population growth and socio-economic development place many of these resources at increasing risk of overexploitation. Using maps and numerous illustrations, The Ecology of the Indonesian Seas describes the complex and ecologically vulnerable coastal and marine ecosystems of the region in rich detail. Discussion of development, resource use and ecologically sustainable management plans is also incorporated. The first step towards sustainable use of marine and coastal resources, this book will be a valuable tool for ecologists, marine biologists, resource managers, government planners, and all those with an interest in the ecology of the region. Bound in two parts, of which this is the first, this book is part of The Ecology of Indonesia series.
Non-Scleractinian Cnidaria
Authors: Tomascik Tomas , Mah Anmarie Janice , Nontji Anugerah , Moosa Mohammad Kasim
Published: November 2023

Even though scleractinian corals are the primary’ builders of present-day coral reefs, skeletal material of other groups, both plant and animal, is incorporated into the construction of the reef matrix. In fact, incorporation, cementation and consolidation of all these calcareous materials, including the corals, is a primary requirement of reef-building, since scleractinian corals rarely, if ever, do it alone. However, large aggregations of massive species, such as Porites, can locally make a significant contribution to die reef matrix (fig. 8.1). While large aggregations of massive Pontes spp. are a common feature of many back-reef and lagoonal environments, they have also been found on the seaward slopes of actively growing reefs. In these instances, they seem to play an important role in the lateral expansion of the reefs. However, on many Indonesian coral reefs, the octocorals (Octocorallia) are a consequential, if not the dominant, component of the coral reef community in terms of abundance, biomass, as well as diversity (fig. 8.2). Class Anthozoa, to which the scleractinian reef-building corals belong, is represented by a number of other groups of organisms that deposit hard skeletons. The Octoco-
Environmental Factors
Authors: Tomascik Tomas , Mah Anmarie Janice , Nontji Anugerah , Moosa Mohammad Kasim
Published: November 2023

The Indonesian Archipelago is one of the most complex marine domains on the planet. The complexity of the Indonesian marine environment (i.e., physical, chemical and biological) is a reflection of its geologic history and atmosphericoceanic interactions. Indonesian seas are among the most productive in the world, and support important coastal and offshore fisheries that are a significant source of protein for millions of coastal people throughout the archipelago. The high productivity of the intra-archipelagic seas is related mainly to high discharge rates of terrigenous material (e.g., nutrients and organic matter) from numerous rivers on Sumatra, Java, Kalimantan, Sulawesi and Irian Jaya, and to various types of geostrophic upwellings which are most pronounced in the eastern parts of the archipelago and along the south coast of Java, Bali and the Lesser Sunda Islands (Wetsteam et al. 1990; Zijlstra et al. 1990). Significant local upwelling also occurs in numerous straits throughout the archipelago, where high-velocity currents cause vertical entrainment of deeper water masses. In addition, many coral reefs in areas with high tidal ranges generate their own daily upwelling events during flood tides by tidal suction (Wolanski 1992). Cold updrafts experienced by divers along steep reef slopes and drop-offs are a manifestation of this common “upwelling” phenomenon throughout the archipelago.
Barrier Reef
Authors: Tomascik Tomas , Mah Anmarie Janice , Nontji Anugerah , Moosa Mohammad Kasim
Published: November 2023

The offshore coral reefs of the Indonesian Archipelago exhibit a high degree of geomorphological complexity. Reef types present range from the classical Darwinian barrier reefs and atolls, to a variety of shelf reefs (e.g., patch and barrier) and oceanic platform reefs. The vast majority of these reefs are found in the central and eastern parts of the archipelago. With the exception of the Kepulauan Seribu patch reef complex (Sunda Shelf) and the reefs of the Spermonde Archipelago (i.e., Spermonde Barrier Reef), it appears that little is known about the offshore reefs of Indonesia.
Anthopogenic Threats
Authors: Tomascik Tomas , Mah Anmarie Janice , Nontji Anugerah , Moosa Mohammad Kasim
Published: November 2023

Anthropogenic threats to shallow-water coastal ecosystems such as coral reefs, seagrass beds, mangroves, intertidal mud flats, rocky shores, and beaches (among others) are numerous. Addressing the serious issue of marine and coastal degradation in Indonesia will require development and implementation of new management plans for the coastal and marine sector, and integrated marine and coastal zone management is the key process. “What is evident from, a number of case studies, such as Kepulauan Seribu (Brown 1986), Jakarta Bay (Tomascik et al. 1994; Suharsono and Tuti 1994) and the inner Ambon Bay, is that side-stepping current environmental issues and spending limited resources to speculate about issues such as the upcoming climate change is questionable, since many shallowwater ecosystems will be lost even before any significant changes in sea level rise are manifested.
Oxidation of the C—H bond
Authors: Bhatia B , Punniyamurthy T , Iqbal J
Published: November 2023

The development of methodology for asymmetric functionalization of the C—H bond offers a challenge in the strive for acquiring optically active building-blocks from simple starting materials. Asymmetric synthesis has emerged as an exciting area of chemistry by judiciously employing the principles of organic synthesis, molecular recognition, metal coordination chemistry, and catalysis. Among the various strategies available for exploiting the pools of chiral compounds, catalytic asymmetric induction offers a distinct advantage in achieving a high level of enantioselectivity during bond formation mainly due to the influence of asymmetry possessed by the ligands in the catalyst. The titanium-catalysed epoxidation1−3 of allylic alcohols, the osmium-catalysed dihydroxylation4−7 of alkenes, the copper-catalysed cyclopropanation8−10 of alkenes, and the ruthenium-catalysed asymmetric hydrogenation11,12 of alkenes are outstanding achievements in the catalytic asymmetric induction approach. Another approach is inspired by the analogy derived from nature, where the monooxygenase enzymes are, for example, known to effect stereospecific oxidation of organic compounds. This biomimetic approach has led to widespread research activity in this area and as a result an impressive start has been made in achieving good levels of selectivity in the oxidation of organic substrates by employing well-crafted small molecular catalysts. The possibility of mimicking the enantio-selective reaction of monooxygenases is a highly viable proposition from the point of view of synthetic organic chemists. Indeed, the design and development of synthetic monooxygenase mimics that catalyse enantioselective epoxidation of unfunctionalized alkenes have already made an impressive impact on stereoselective synthesis mainly due to the pioneering efforts of the research groups of Groves, Jacobsen,15,17 and Katsuki,18−22 respectively. On the other hand, the enantioselective oxidation of the saturated C—H bond has proven more difficult to accomplish with synthetic catalysts. Consequently, there has been continual effort to achieve a high level of enantioselectivity in the oxidation of the saturated C—H bond over the past few years. The following sections deal with the results achieved so far on the enantioselective oxidation of the C—H bond by employing chiral catalysts derived from ligands easily prepared from simple and easily accessible starting materials. The emphasis is on the experimental procedures of those reactions which are operationally simple and easy to perform on a synthetically useful scale.
Oxidation ofhetero atoms
Authors: Kagan H B
Published: November 2023

During the later Palaeocene and early Miocene, catarrhine primates and the evolving hominoids had adaptations for frugivorous diets, with the emphasis on soft foods. Early in the middle Miocene the hominoids underwent a major shift, both in morphology and in habitat, with the morphology characterized by thickened enamel on the molars, enlarged incisors and massive jaws. The diet indicated by this morphology is interpreted as still mainly frugivorous but with changed emphasis, possibly towards harder objects. The thick-enamelled hominoids are found associated with more open forest habitats, and the distribution of food resources in equivalent habitats today is discontinuous both in time and in space, leading to evolutionary pressures particularly affecting locomotion, brain size and social behaviour. The earliest known hominid fossils differed little in dental and mandibular morphology from the middle Miocene apes, and the implied dietary similarity, together with ape-like patterns of dental development and retained arboreal adaptations of the postcrania, suggests little change in the foraging strategies of the earliest hominids compared with their ape ancestors and further suggests similarity in evolutionary grade. This similarity may have extended to other aspects of behaviour, for example to patterns of tool making and use, which may have been similar in the common ancestor of apes and humans to the pattern shared by the earliest australopithecines and chimpanzees.
Oxidation using a biocatalyst
Authors: Azerad R
Published: November 2023

Since the first demonstration by Murray and Peterson1−3 that a filamentous fungus, Rhizopus arrhizus,was able to convert progesterone to lla-hydroxy-progesterone efficiently (Scheme 5.1.1), many substances, either of natural or synthetic origin, have been examined using a variety of microorganisms (bacteria or fungi). Only a few examples will be given here. For a more exhaustive coverage, the reader is referred to books 4−6 or reviews dedicated to the microbial hydroxylation of the most common substrate groups such as steroids,7−13 alkaloids,8,14−16 terpenes,17,18 and synthetic materials.
Introduction to the cuckoos
Authors: Payne Robert B
Published: November 2023

The parasitic breeding behavior of cuckoos has fascinated people for centuries. The brood-parasitic cuckoos lay their eggs in the nests of other kinds of birds, and never rear their own young (Johnsgard 1997, Rothstein and Robinson 1998, Davies 2000). The natural history of the Common Cuckoo Cuculus canorus and the Great Spotted Cuckoo Clamator glandarius, the two species that live in Europe where they have been observed for many years, is well known. In Classic times,Aristotle studied the brood-parasitic behavior of Common Cuckoos (Friedmann 1964b,Aristotle 1991), and in Britain Shakespeare referred to cuckoos in his plays. The term “cuckoldry” was often used in the sense of an adulterous affair, and the implications of immorality in a later period led to a censored version of Shakespeare that eliminated the term “cuckold” (Bowdler 1861, Hamilton 1996). Many other species of brood-parasitic cuckoos live in Africa, Asia and Australia and in Central and South America where they have been watched by resident naturalists. Brood-parasitic cuckoos are diverse with 56 species in the Old World and three in the New World.
Block copolymers in dilute solution
Authors: Hamley Ian W
Published: November 2023

The formation of micelles in a solvent that is selective for one of the blocks is one of the most important and useful properties of block copolymers. For example, micelles formed by block copolymers can solubilize otherwise insoluble substances, they can be used to microscopically ‘mix’ incompatible substances and they can stabilize colloidal particles or form microemulsions.
Polymer blends containing block copolymers
Authors: Hamley Ian W
Published: November 2023

In blends of two or more homopolymers with block copolymer, there is an interplay between macrophase separation of the homopolymers and microphase separation of the block copolymer. Which effect predominates depends on the relative lengths of the polymers, and on the composition of the blend.
Library synthesis on resin beads
Authors: Terrett Nicholas K
Published: November 2023

The synthesis of combinatorial libraries usually employs solid phase chemistry. The recent renaissance and growth of interest in solid supported chemistry stems from the opportunity to use filtration as a separation technique to purify both intermediates and final compounds. The ability to synthesize compounds on a resin bead for example, to force the reaction to completion by the addition of excess reagents and monomers, and then being able to remove all the unwanted materials by a simple filtration and wash is at the heart of many library syntheses (Fig. 2.1).This is not to say however, that solution methods are no longer suitable for combinatorial libraries. With appropriate chemistry, either that which is high yielding or that generates products which allow simple liquid-liquid extraction, solution phase library synthesis is highly feasible (see Chapter 4) and indeed has been chosen as a preferred strategy by many academic and industrial groups.
Further chain reactions of stannanes
Authors: Zard Samir Z
Published: November 2023

Except for Sections 3.8 and 3.9, where we shall examine the synthetic potential of generating stannyl radicals by ,ᵝ-scission (in contrast to hydrogen abstraction from a triorganotin hydride), most of this chapter will be devoted to radical rearrangements. A radical cyclization may be considered as a special case of a rearrangement (or isomerization) process. The radical site thus moves along the molecule from one position to another, with one or more new CT-bonds being formed at the expense of a corresponding number of ᚂ-bonds.
Introduction
Authors: Goldstein Barry J
Published: November 2023

Covalent modification of proteins by phosphorylation and déphosphorylation has long been appreciated to be an essential physiological mechanism for the control of cellular function. The extensive molecular and biochemical characterisation of tyrosine kinases that has taken place through the 1980s has now been followed by studies on a rapidly emerging super - family of complementary enzymes, the protein-tyrosine phosphatases (P TP ases; EC 3.1.4.38), which reverse the effect of the kinases and serve to dephosphorylate protein-tyrosine residues of cellular substrate proteins [16, 26]. Work on reversible protein phosphorylation was highlighted by the awarding of the 1992 Nobel Prize in Physiology or Medicine to Drs Edmond Fischer and Edwin Krebs for their fundamental contributions in this area. Although the phosphorylation of protein-tyrosine residues represents only a small fraction of the overall modification of cellular proteins by phosphorylation, which occurs primarily on serine and threonine residues, this reversible protein alteration has been demonstrated to be involved in many critical aspects of cellular physiology. Reversible tyrosine phosphorylation mediates the regulation of cell growth, cell division and differentiation as well as responses to tyrosine kinases that are expressed in cells as plasma membrane receptors or as non-receptor tyrosine kinases. PTPases have been considered to balance the steady-state phosphorylation of a variety of cellular tyrosine kinase substrates and influence cellular signal transduction by attenuating the activity of activated (autophosphorylated) tyrosine receptor kinases or by participating in an on–off switching mechanism mediated by reversible tyrosine phosphorylation of substrate proteins involved in downstream signalling.
Applications of phosphorus (III) and (V) compounds as reagents in synthesis
Authors: Alan Aitken R , Karodia Nazira
Published: November 2023

Phosphorus compounds play a key role in organic synthesis and in many cases they provide the reagent of choice to bring about a particular transformation. Central to this is the great affinity of phosphorus for oxygen and sulfur. The main reaction types which may be identified are: (i) deoxygenation and desulfurization, (ii) halogenation, (iii) dehydrative coupling and cyclization, (iv) sulfurization, and (v) miscellaneous processes. In this chapter these areas are considered in turn and examples of typical reaction protocols are given for each. In doing this we have included not only organophosphorus reagents but also some important inorganic phosphorus compounds, which are among the most valuable and powerful reagents available to the synthetic chemist. A detailed treatment of the use of organophosphorus reagents in many of the reaction types considered here is available in the relevant chapters of a 1979 monograph.
Human evolution: our turbulent genes and why we are not chimps
Authors: Dover Gabriel
Published: November 2023

We might not know why we are the way we are, but the one thing which is certain is that we sometimes regard ourselves, Homo sapiens sapiens,as qualitatively different from the rest of the living world. The species-centric question that would arise in most minds is, I believe, ‘why is our species different from all other species?’, rather than considering the more modest question of why we are not chimps.
The mechanical telegraph
Authors: Solymar Laszlo
Published: November 2023

The seventeenth century did not start well for independent thinking. In the year 1600 Giordano Bruno, a believer in the Copernican system, was burnt at the stake. Galileo, another believer, escaped a similar fate only by recanting his views in 1633. However, looking at the century as a whole, it was undoubtably the beginning of modern science. Besides Galileo, Kepler and Harvey, who entered the century as mature men, it was the century of Descartes, Leibniz, Newton and Pascal, and of many others like Fermat, the mathematician, Torricelli with his barometer, Boyle and Marriotte of gas laws fame, von Guericke with his electric friction machine and unbreakable hemispheres, Vernier of the Vernier scale, and universal geniuses like Huygens and Hooke.
The telephone
Authors: Solymar Laszlo
Published: November 2023

The mechanical telegraph was born in war. The electrical telegraph, although born in peace, soon became an instrument of war, and as has been seen, played a significant role in politics both internal and external. In contrast, the telephone made no major impact upon the battle-field. It might have made Mrs Jones an enemy of Mrs Smith on account of what she said about her to Mrs Robinson in the course of their lengthy telephone conversations but it did not in many other ways contribute to the spread of hostilities. Its effect on matters diplomatic was also slight. It rose to importance only in recent times with the establishment of the hot line between Kruschev and Kennedy.
The telephone revisited
Authors: Solymar Laszlo
Published: November 2023

The telephone made great strides ahead in a very short time. By 19n, as mentioned in Chapter 5, it was possible to make a call from New York to Denver, 4300 km away, but obviously that was not far enough. Ambitions were much higher: firstly, to span the continent from New York to San Francisco, secondly to establish telephone connections between the US and Europe, and finally to enable people to conduct conversations between any two points on Earth.
The solid state revolution
Authors: Solymar Laszlo
Published: November 2023

Solid state physics, as the name implies, is concerned with the physical properties of solid bodies, in particular what happens to them when they are exposed to external influences e.g. heated, voltage applied across them or light shone upon them. This was of course a science that was already flourishing in the nineteenth century but with serious limitations. The theories available at the time could explain only a fraction of the experimentally found phenomena. Entirely new departures were needed.
Digitalization
Authors: Solymar Laszlo
Published: November 2023

An analogue signal, like voice, can take any value. Its amplitude is low when we whisper and high when we shout. The job of the telephone network is faithfully to reproduce all those voice signals, however long the line is. It’s not an easy thing to do. The difficulty is with noise. It is bound to distort the signal. Take lightning for example. It causes an electrical disturbance which clearly affects the amplitude of the voice signal. When the signal is demodulated and turned back into sound a sharp, unpleasant click is heard.
Stochastic Model of Liquid Filtration in Porous Media with Large-Scale Inhomogeneities
Authors: Aprosin D V , Brenerman M H , Kessel A R
Published: November 2023

Universally accepted hydrodynamical models of oil displacement are applicable only when the oil stratum has micro-scale inhomogenities and can be modelled as a continuous medium. For solid-liquid stratums with large scale inhomogeneities, an alternative stochastic approach is suggested here using dynamic percolation theory instead of traditional differential equations. A system of kinetic equations is obtained on a regular lattice, analogous to those in statistical physics. Numerical simulations find the non-stationary pumping regimes which give larger displacement fluxes than in the stationary case. The model explains the existence of a liquid phase with closed clusters, the non-linear variation from Darcy’s law, and the existence of a pressure threshold of the “phase transition”.
Stochastic Geometric Model of Combustion in Two-Phase Turbulent Flow
Authors: Brenerman M H , Kessel A R
Published: November 2023

The universally accepted continuous mixture (CM) models are valid for describing two-phase flows (TPF) with inhomogenities, whose characteristic size is much less than the scale of the problem. Generally speaking, TPF characterized by large-scale inhomogeneities cannot be described by CM models. A combined Eulerian-Lagrangian mathematical model of combustion in TPF with large-scale inhomogenities is presented here. It treats the kinetics of the carrying phase as a random process and the kinetics of the dispersed phase as a random walk (macro-scale Lagrangian approach). The interaction between the particles and the carrying phase is chosen in a classical form (micro-scale Eulerian approach). Differential equations are replaced by a random walk simulation scheme. This approach takes into account some phenomenological details of TPF and explains the effect of incomplete burning, which contradicts CM models.
Nonclassical β-lactam antibiotics
Authors: Cabri Walter , Fabio Romano Di
Published: November 2023

Since their discovery 60 years ago, β-lactam antibiotics have been used in the fight against infectious diseases, one of the main causes of death at the beginning of the last century, and have contributed to a marked rise in life expectancy. The early demonstration of the clinical usefulness of the first series of naturally occurring penicillins and the rapid spread of resistant bacteria strains soon after their introduction in clinical practice fuelled an extensive and continuous effort by the pharmaceutical industry to find more potent and efficacious antibacterial agents.
Before We Proceed
Authors: Holland John H
Published: November 2023

I wondrous vine emerges when Jack plants the seed for his beanstalk, and it unfolds into a world of giants and magic harps. When we were children, Jack’s miraculous beanstalk wasn’t so far removed from the everyday miracles of fall colors and germinating seeds. Now that we’re grown, seeds still fascinate us.
Checkers
Authors: Holland John H
Published: November 2023

Any serious study of emergence must confront learning. Despite the perpetual novelty of the world, we contrive to turn experience into models of that world. We learn how to behave, and we anticipate the future, using the models to guide us in activities both common and uncommon. Somehow, through learning, these models emerge from the torrent of sensations that impinge upon us at every moment. Certainly, a deeper understanding of learning will contribute to a deeper understanding of emergence. In attempting to understand the relation between learning and model building, we could scarcely find a better starting point than Art Samuel’s mechanization of learning in the checkersplaying program.
Salt marshes and mangrove swamps
Authors: Little Colin
Published: November 2023

On their upper tidal levels, most marine and estuarine mudflats are hidden by vegetation. In temperate zones, salt-tolerant grasses and other herbaceous plants form what is called salt marsh. Here in spring and summer the white flowers of scurvy grass or the yellow of asters and the purple of sea lavender form colourful swathes against a background of cordgrass, while in winter the vegetation dies back to brown remnants.
Estuarine habitats and coastal lagoons
Authors: Little Colin
Published: November 2023

Sediments from coarse gravel to fine mud can be found in varying degrees both on relatively open coasts and in shelter. The greatest reservoir of sediments is in the sublittoral zone, stretching down to the deep sea. But the most easily accessible and most varied accumulations occur in estuaries, so not surprisingly a great majority of soft-sediment researchers have concentrated their efforts there. Estuaries are more than just indentations in the coastline, however, and provide a variety of characteristics that differentiate them from strictly marine environments.
Life in the estuarine water column
Authors: Little Colin
Published: November 2023

In many ways, physical conditions in the estuarine water column are more rigorous than in the benthos. For example, there is no buffering by the sediment against sudden changes in salinity. But in fact the plankton does not often have to face the problem of great changes in salinity because the organisms travel with bodies of water rather than staying still while water of different salinity washes over them. There is also the constant problem that organisms may be washed out to sea. Nevertheless, some estuaries contain flourishing populations of plankton, fish, and swimming crustaceans, and as we shall see they often act as nursery grounds for fish species that mature in the sea.
Neutron crystallography of biological molecules
Authors: Pcbay-Peyroula Eva , A1yles Dean
Published: November 2023

In the past decade, the number of protein structures solved at atomic resolution by X-ray crystallography has increased dramatically Developments in molecular biology, crystallization techniques, synchrotron radiation facilities and the associated progress in two-dimensional detectors now make possible the solution of very complex structures with a large number of atoms, at atomic or near atomic resolution, even from very small crystals. However, at the medium resolution limits (> 1.5 A) typical of most X-ray protein structure determinations, these analyses are invariably incomplete: hydrogen atoms—which account for 50% of the contents of the cell—often cannot be seen at all.
Small-angle X-ray scattering by solutions of biological macromolecules
Authors: Vachette Patrice , Svergun Dmitri
Published: November 2023

This chapter on the application of Small-angle X-ray scattering (SAXS) to biological macromolecules can be read independently from other contributions in the series of volumes of Hercules lectures but it does not ignore them. The general considerations on the phenomenon of light scattering by matter are kept to a minimum and focused on the case of particles in solution. The reader is referred to the contributions by Geissler (1994) and Williams (1993) for further developments presented from a different standpoint. The section on data analysis and the formalism of spherical harmonics can be complemented by reading the contribution by Stuhrmann (1994). The question of interactions between particles is barely touched upon since it has been dealt with byTardieu (1994). Finally this chapter is obviously not the place for an exhaustive presentation of the theory of SAXS. Beyond the other contributions already mentioned, the interested reader is referred to the textbooks listed in the bibliography.
The quest for high resolution phasing for large macromolecular assemblies exhibiting severe non-isomorphism, extreme beam sensitivity and no internal symmetry
Authors: Yonath Ada
Published: November 2023

The translation of the genetic code into polypeptide chains is a fundamental life process. In rapidly growing bacterial cells the biosynthetic machinery constitutes about half of the dry weight of the cell, and the biosynthetic process consumes up to 80% of the cell’s energy. Among the over 100 different compounds participating in the biosynthetic process is a giant riboprotein complex which has been studied crystallographically for quite some time: the ribosome, an unstable 2350 kDa assembly of many proteins and RNA of diverse structures. This universal organelle mediates the translation step of the biosynthetic process by catalysing the sequential polymerization of amino acids according to the blueprint, encoded in the mRNA [for recent reviews see Wilson and Noller (1998), Yonath and Franceschi (1998)].
One-dimensional Variational Problems
Authors: Buttazzo Giuseppe , Giaquinta Mariano , Hildebrandt Stefan
Published: November 2023

One-dimensional variational problems have been somewhat neglected in the literature on calculus of variations, as authors usually treat minimal problems for multiple integrals which lead to partial differential equations and are considerably more difficult to handle. One-dimensional problems are connected with ordinary differential equations, and hence need many fewer technical prerequisites, but they exhibit the same kind of phenomena and surprises as variational problems for multiple integrals. This book provides an modern introduction to this subject, placing special emphasis on direct methods. It combines the efforts of a distinguished team of authors who are all renowned mathematicians and expositors. Since there are fewer technical details graduate students who want an overview of the modern approach to variational problems will be able to concentrate on the underlying theory and hence gain a good grounding in the subject. Except for results from the theory of measure and integration and from the theory of convex functions, the text develops all mathematical tools needed, including the basic results on one-dimensional Sobolev spaces, absolutely continuous functions, and functions of bounded variation.
Broadening Electrochemical Horizons
Authors: Bond A M
Published: November 2023

Electrochemistry is a well established discipline that has encompassed both applied and fundamental aspects of chemistry courses for nearly a century. In recent years, however, it has become obvious that even broader applications of this valuable technique are now available to advance knowledge and solve problems in organic, inorganic and biological chemistry. In this book, it is shown how a range of limitations that historically have restricted the use of voltammetric and related electrochemical techniques have been removed or minimised so that it is now possible to work in the gas and solid phases as well as the traditional liquid phase. Significant advances in theory, instrumentation and electrode design have also made the technique more user-friendly. The initial chapters of this book describe the basic theory and philosophy behind the modern, widespread use of voltammetric techniques. The later chapters provide examples of new areas of application and predict future possibilities for this exciting area.
Spin Choreography
Authors: Freeman Ray
Published: November 2023

Nuclear magnetic resonance (NMR) spectroscopy, a technique widely used for structure determination by chemists and biochemists, is based on the detection of tiny radio signals emitted by the nucleus of an atom when immersed in a strong magnetic field. Every chemical substance gives rise to a recognizable NMR signature closely related to its molecular structure. This comprehensive account adopts an accessible, pictorial approach to teach the fundamental principles of high resolution NMR. Mathematical formalism is used sparingly, and everyday analogies are used to provide insight into the physical behaviour of nuclear spins. The first three chapters set out the basic tools for understanding the rest of the book. Each of the remaining chapters provides a self- contained reference to a specific theme, for example spin echoes, and traces the way it influences our understanding of high resolution NMR methodology. Spin Choreography provides a clear and an authoritative introduction to the fundamental princilples of high resolution NMR, which will appeal to all practictioners who wish to master this complex but fascinating subject. The book will also serve as supplementary reading for upper-level undergraduate and graduate courses on spectroscopy and physical methods.
Energy levels
Authors: Freeman Ray
Published: November 2023

Spectroscopy provides direct and incontrovertible evidence of quantization of energy, and nowhere is this more simply illustrated than in magnetic resonance experiments. Textbooks on quantum mechanics would surely have chosen spin systems as their starting point, rather than atomic spectra, had magnetic resonance been discovered at an earlier date. The resonance lines which we observe in high resolution NMR spectra are transitions between these energy levels. However, in contrast to conventional spectroscopy, the separation between levels is a function of the applied magnetic field. Many modern NMR experiments, for example correlation spectroscopy or multiple-quantum spectroscopy, become clearer if we think in terms of the appropriate energy level diagram. The populations of these energy levels are important in studies of spin-lattice relaxation, the nuclear Over hauser experiment and chemically induced nuclear polarization. On a more mundane level, the general form of the conventional NMR spectrum can be predicted on the basis of the energy level diagram appropriate to that particular spin system.