bluuebunny/crossref_metadata_2025 huggingface dataset:
Retinoic acid receptors and binding proteins in mouse limb development
Authors: Ruberte Esther , Nakshatri Harikrishna , Kastner Philippe , Chambon Pierre
Published: November 2023

The vertebrate limb appears as an outgrowth in the flank of the embryonic body. Initially it consists of a mesenchymal core covered by a layer of ectoderm. During the elongation of the limbs the apparently homogeneous population of the mesenchymal cells gives rise to different cell types: cartilage, bone, muscle, and other tissues, that develop in appropriate spatial relationships to constitute the developed limb. From grafting experiments that have been performed mainly in the chick, it appears that two mechanisms are involved in the formation of the proximodistal (from the base to the tip) and the anteroposterior (from the thumb to the little finger) pattern of the limbs. Development of the proximodistal axis involves the mesenchymal cells in the distal tip of the limbs, which through a mesenchymal-ectodermal interaction, induce the overlying ectoderm to thicken. This results in the formation of a pseudostratified columnar epithelium known as the apical ectodermal ridge (AER). This ridge appears to be essential for the outgrowth of the limbs and grafting experiments have shown that its removal results in a truncated limb (Zwilling 1956; Saunders and Gasseling 1968). Once the AER is formed it exerts an inductive influence on the underlying mesenchyme, which grows rapidly and differentiates. Positional values along the proximodistal axis are defined by the time spent in an area of undifferentiated mesenchyme under the tip of the bud, known as the progress zone (Summerbell et al. 1973). Cells leaving the progress zone at early times differentiate into proximal structures, while the cells that leave the progress zone later give rise to distal structures.
Differential regulation by retinoic acid of the homeobox genes of the HOX family in human embryonal carcinoma cells
Authors: Boncinelli Edoardo , Simeone Antonio , Acampora Dario , Faiella Antonio , D”Esposito Maurizio , Stornaiuolo Anna , Pannese Maria , Mallamaci Antonio
Published: November 2023

Morphogens, which convey positional information and induce pathways of differentiation through a gradient of concentration, are believed to play a key role in vertebrate development (Brockes 1989). Retinoic acid (RA) has been implicated as a natural morphogen in chicken development, where it contributes to the specification of the limb anterior-posterior (AP) axis (Tickle et al. 1982; Thaller and Eichele 1987). There is also a possible implication in frogs, where alteration of embryonic RA levels dramatically affects specific structures of the developing central nervous system (Durston et al. 1989), although these interpretations have recently been reconsidered (Brockes 1991). The identification of specific cellular RA binding proteins and of a number of nuclear RA receptors in mouse and man supports the concept that this substance may act as a morphogen with direct gene control functions. Although the genes involved in interpreting signals provided by morphogens are still unknown, homeobox genes, which specify positional information in Drosophila and possibly in vertebrate embryogenesis, are among suggested candidates. Extensive genetic analysis of early embryogenesis in Drosophila has provided insights into the molecular events controlling body plan formation and, in particular, the process of segmentation and the specification of segment identity along the body axis. These processes are controlled by a relatively limited number of genes, which appear to be organized in a complex regulatory network (Akam 1987). Most of them encode DNA-binding proteins with a role in transcriptional control (Levine and Hoey 1988). The DNA-binding domain present in these proteins is often a homeodomain (HD) encoded by a homeobox (Gehring 1987). Genes containing a homeobox code for nuclear proteins with regulatory functions in a wide variety of organisms, from yeast to man (Scott et al. 1989). Many of these genes appear to have a role in control of the early developmental programme. Unravelling this regulatory network is critical for our understanding of development.
Hox-4 genes, retinoic acid, and the specification of positional information during chick wing morphogenesis
Authors: Izpisúa-Belmonte Juan-Carlos , Dollé Pascal , Tickle Cheryll , Wolpert Lewis , Duboule Denis
Published: November 2023

The morphogenesis of the vertebrate limb is a widely used model system to study the cellular and molecular basis of positional signalling processes during development. A conceptual framework for pattern formation was provided by Wolpert (1969) who proposed that various cells within a developing system could have their positions specified relative to one or more reference points or organizing regions. Accordingly, each cell would then interpret its own positional value and respond by differentiating in a particular way according to its developmental history. Cells highly related, phenotypically and functionally, would therefore appear as “non-equivalent” (Lewis and Wolpert 1976) as far as patterning is concerned. The nature of the genetic control of”non-equivalence” is largely unknown, but the past few years have provided us with serious candidate genes for encoding positional information. Among them are the homeobox-containing (HOX) genes, which are the vertebrate gene cognates of the Drosophila homeotic genes. In insects, these genes specify the identities of the various parasegmental units in a position-dependent manner. In vertebrates, functional and circumstantial evidence suggest that the Hox genes encode positional information. Hox genes are responsive to retinoic acid (RA) treatment in vitro (Simeone et al. 1990) and it is well established that retinoids can respecify patterns in the developing vertebrate limb (Tickle et al. 1982, 1985). Here we discuss evidence that genes from the vertebrate Hox-4 complex might play a role in setting-up positional cues during mouse and chick limb development and that the expression of these genes can be regulated by RA in vivo.
Towards vaccines against papillomavirus
Authors: Campo M Saveria
Published: November 2023

As already described elsewhere (Chapter 2), papillomaviruses induce a variety of lesions both in humans and in animals. Some papillomas, albeit benign, are themselves a clinical problem, such as laryngeal papillomas of children (Steinberg 1987) or penile papillomas of bulls (Jarrett 1985), and others are known to be a risk factor in the pathogenesis of cancer. In humans, papillomavirus infection of the genital tract can lead to squamous cell carcinoma particularly in the uterine cervix (zur Hausen 1991), and infection of the skin by certain virus types can develop into squamous cancer in immunosuppressed individuals (Orth 1987). In animals, the link between papillomavirus and cancer of the skin in rabbits, and of the urinary bladder and the upper alimentary canal in cattle, is well documented (Kreider 1980; Campo and Jarrett 1986; Campo et al. 1992).
Quantification of grains in in situ hybridization
Authors: Aldridge Jane
Published: November 2023

Image analysis provides a wide range of sophisticated measurement techniques. Even so, it is often difficult to analyse histological and cytological preparations automatically since, in many cases, standard detection methods simply do not interpret the image well enough on their own to find the regions to be measured. This is particularly true for radiolabelled in situ hybridization. The issue of recognition is complex, since the best approach to interpreting an image automatically often depends on background information about the sample and about the aims of the experiment. Important changes in the approach adopted by manufacturers of image analysis equipment are promising advances. The first is a shift away from developing general analysis software and towards developing analysis software that will solve particular problems in interpreting types of images.
The Sawflies And Woodwasps
Authors: Smith David R
Published: November 2023

As is traditionally recognized (e.g. by Gauld & Bolton, 1988; Naumann, 1991; Smith, 1993), the suborder Symphyta (the sawflies and woodwasps) is a para phyletic assemblage comprising the structurally more primitive Hymenoptera. Symphytan adults share a number of primitive (plesiomorphic) character states: their abdomen is broadly joined to the thorax and not constricted at its base, the first abdominal segment is not fused with thorax (i.e. propodeum absent), cenchri are present on the metathorax (except the non-Costa Rican family Cephidae), a trochantellus is present, and numerous enclosed cells are discernible in the wings, including one or more anal cells in the fore wing (except in most Pergidae). While the Orussidae share most of these plesiomorphic character states with the sawflies and woodwasps, they also share several apo morphic character states with the suborder Apocrita (Gibson, 1985; N.F. Johnson, 1988; Whitfield et al., 1989; see Chapters 5 and 7). Moreover, the larval stages of Orussidae differ from all other symphytans in being parasitic or predatory rather than phy tophagous. Therefore the orussids are treated in a separate chapter (Chapter 7).
The chrysidoid families
Authors: Gauld Ian D , Hanson Paul E
Published: November 2023

The superfamily Chrysidoidea is a monophyletic clade that is the sister-group to the other two aculeate super families (Brothers, 1975). It comprises seven extant monophyletic families, the Bethylidae, Chrysididae, Dryinidae, Embolemidae, Plumariidae, Sclerogibbidae and Scolebythidae. The most recent and comprehensive investigation of the phylogeny of the group is the work of Carpenter (1986a) who postulated the phylogenetic relationships shown in Fig. 13.01.
The lower vespoid families
Authors: Brothers Denis J
Published: November 2023

The superfamily Vespoidea is almost certainly a mono phyletic clade which is the sister group of the Apoidea (Brothers, 1975; Brothers & Carpenter, 1993). Unlike the Chrysidoidea and the Apoidea, however, the Vespoidea does not appear to possess any unique synapomorphies, mainly being characterized by the reduced prepectus. It comprises ten extant mono phyletic families (Fig. 14.01). The most recent and comprehensive study of the phylogeny of the families (and some subfamilies) of Vespoidea is that of Brothers and Carpenter (1993) who re-evaluated the work of Brothers (19 75) and subsequent authors. The phylogeny shown in Fig. 14.01 represents our present best estimate of their relationships.
The Bees(Apidae)
Authors: Griswold Terry , D.Parker Frank , E.Hanson Paul
Published: November 2023

Diagnosis Body length 1.5 to 46.0 mm, in Costa Rica ranging from the minute stingless bee Trigonisca discolor (less than 3 mm) to the robust carpenter bee Xylocopa nautlana (more than 30 mm). Black, brown, reddish, yellow, sub-metallic, or brilliantly metallic blue, green, or coppery; a few are marked with yellow or white. Pubescence ranges from nearly absent to very long and dense, varying in colour but always having at least some plumose hairs, especially in the vicinity of the mesothoracic spiracle, the upper part of the propodeum and the lateral portions of the metanotum. Both sexes always fully winged; sexual dimorphism slight.
Ecology of South Turkana
Authors: Little Michael A , Dyson-Hudson Rada , Mccabe J Terrence
Published: November 2023

The territory of the Ngisonyoka section of South Turkana is a part of Turkana District, which is located in the north-west corner of Kenya and is the northernmost and largest district of Kenya’s Rift Valley Province. It is one of the driest areas of Kenya. Pratt and Gwynn (1977) classify the region as including semi-arid, arid, and very arid ecoclimatic zones. These zones are characterized by very high temperatures, and rainfall between slightly more than lO0mm/year in the very arid zone to 600mm/year or more in the semi-arid zone; and vegetation ranging from desert scrub and sparse annual grassland (very arid) to dwarf-shrub annual grassland (arid) to wooded grassland and bushland with dense stands of perennial grasses (semi-arid). Considerable woody vegetation is found in riparian groundwater areas that result from the braided drainage systems on the several plains, and in riverine forests along the Kerio and Turkwel Rivers (Coughenour et al. 1990c; Coughenour and Ellis 1993; Wyant and Ellis 1990).
Infant care and feeding
Authors: Gray Sandra J
Published: November 2023

Infant care and feeding practices represent, perhaps, the keystone of human adaptive strategies, since they impact both directly and indirectly on human fertility and child survival. The structure of breast-feeding in a population directly influences human fertility through its effects on the duration of postpartum amenorrhoea and on birth spacing. The structure of the weaning process influences fertility both directly, through maternal hormonal changes induced by reduced suckling, and indirectly, through its impact on infant and weanling morbidity and mortality. This chapter begins with a brief discussion of the biological, behavioral, and environmental factors which contribute to cross-cultural variation in infant care and feeding. Next, breast-feeding and weaning practices among Turkana pastoralists are examined, with particular attention to the constraints on infant feeding in the Turkana setting and to maternal strategies used to negotiate within those limits. Finally, an ecological model is presented which summarizes relationships between the infant feeding practices, the variables which influence them, and reproductive strategies among nomadic Turkana.
People and herds
Authors: Leslie Paul W , Dyson-Hudson Rada
Published: November 2023

Humans and livestock in Turkana are intimately interdependent. Nomadic Turkana depend on livestock for virtually all their food (Chapter 7); and livestock depend on humans for protection and regular access to resources—forage and particularly water. This means that there is a continual and close association between the densities and distributions of human and livestock populations across the landscape. Although the importance of understanding the demography of both human and livestock populations has long been recognized (Stenning 1959), demographic studies of pastoralists, especially nomadic pastoralists, have been scarce until the past decade, and studies of the population dynamics of their herds remain rare. In this chapter, we consider the relationship between the Turkana and their livestock at the population level, and provide a background for the demographic studies that form the basis for Chapters 13, 14, 15 and, to a lesser extent, 17.
Road traffic growth and the dynamics of sustainable transport policies
Authors: Goodwin Phil
Published: November 2023

Professor Phil Goodwin, BSc (Econ), MA, PhD, is one of Britain’.s leading experts on transport economics and policy. After taking his first degree, in economics, and a PhD in Civil Engineering (Transport Studies) at University College, London, Professor Goodwin joined the Department of Planning and Transportation of the Greater London Council in 1974. He served as Acting Head of the Public Transport Economics Section of that Department and then as Transportation Economics Advisor to the Council. In 1979, Professor Goodwin moved to Oxford, where he joined the University s Transport Studies Unit. He was appointed in 1981 to a University Readership in Transport Studies and to the Directorship of the Unit; in the following year he was elected to an Official Fellowship of Linacre College and, in 1990, to a Professorial Fellowship of the College. In 1996 Professor Goodwin returned to University College, London, to take up the appointment of Professor of Transport Policy there. He is a member of the Standing Advisory Committee on Trunk Road Assessment (SACTRA) and has advised a large number of bodies and institutiom both national and local, on transport matters. Professor Goodwin is the author of’ numerous articles and reports on transportation and gave evidence to the Royal Commission on Environmental Pollution.
Mechanistic insights into tumour angiogenesis
Authors: Bicknell Roy
Published: November 2023

As outlined in Chapter I there are two recognized processes by which new blood vessels are formed. These are called vasculogenesis and angiogenesis. Vasculogenesis describes the formation of new vessels from the endothelial presursors that are present in the blood islands of the developing embryo. Angiogenesis is the development of new blood vessels from pre-existing blood vessels. In the adult, all new blood vessels arise by angiogenesis.
Prognostic and predictive value of intra-tumoral microvessel density in human solid tumours
Authors: Gasparini Giampietro
Published: November 2023

The majority of human solid tumours are heterogeneous diseases, made up of multiple cell clones with diverse biological aggressiveness (1,2). The tumour cell heterogeneity is the result of the genomic instability (3) due to genetic alterations that may include: mutations, deletions, chromosomal rearrangements, activation of oncogenes, downregulation of tumour suppressor genes, and gene amplification (4-7). Tumour cell heterogeneity may confer different properties of growth, immunogenicity, ability to metastatize, and sensitivity to treatments to the diverse cell clones. Tumour cell genomic instability and heterogeneity are the biological basis of the clinical observation that both the outcome of the patients and their responsiveness to anti-cancer therapy may be different among tumours classified as having the same pathological or clinical stage. Thus, for several solid tumours it is difficult, by using conventional clinicopathological criteria, to assess the prognosis or the likelihood of response to a specific form of anti-cancer treatment of any single patient.
The physiological importance and therapeutic potential of nitric oxide in the tumour-associated vasculature
Authors: Hirst D G , Flitney F W
Published: November 2023

The relationship between malignant tumours and their vascular supply differs in many respects from that of most normal tissues. Tumour vasculature is characterized by rapid proliferation (1,2), increased permeability (3,4), and disorganized architecture (5-8), properties which are both a cause and a consequence of inadequate perfusion and oxygenation (9). We may summarize the condition of tumour vasculature as a system that is maximally stimulated, yet still unable to meet the metabolic demands of the tissue it supplies. The consequences of this for cancer therapy are profound (I 0,11 ). An inadequate vascular network leads to a heterogeneous blood supply and to areas within most tumours that are deprived of the limiting metabolic substrate, oxygen (12-14). This in turn creates regions with radiobiologically hypoxic cells which are both resistant to radiotherapy and quiescent. The lack of proliferative activity protects them from many chemotherapeutic drugs which are proliferation-dependent in their cytotoxic action. It should occasion no surprise then, that the influence of vasoactive agents on tumour blood flow has received considerable attention over the last 20 years (15,16) and this approach is still seen as a mechanism through which the action of anti-cancer agents could be enhanced. This review will focus on the importance of one highly topical vasoactive molecule, nitric oxide (NO). While the importance of this molecule in cancer therapy generally has been considered in a recent review (17) we will focus on its role in tumour-associated vasculature and evaluate its potential as a target for cancer therapy in this context.
Thymidine phosphorylase/ platelet-derived endothelial cell growth factor: an angiogenic enzyme
Authors: Moghaddam Amir , Chaudhuri Rangana , Bicknell Roy
Published: November 2023

Thymidine phosphorylase is an angiogenic enzyme which is overexpressed in many solid tumours. In contrast to other well characterized angiogenic molecules such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) it is not a mitogen for endothelial cells nor is it heparin binding. The fact that thymidine phosphorylase is an angiogenic molecule, an enzyme involved in nucleotide homeostasis and not a classic growth factor makes it a particularly intriguing molecule to study. It is now known that the product of thymidine/phosphorylase action on thymidine, 2-deoxyD-ribose, is angiogenic and it is release of this that mediates the angiogenic activity of the enzyme. This chapter reviews the studies that have led to the identification of thymidine phosphorylase as a potential regulator of both physiological (e.g. endometrial) as well as tumour angiogenesis.
Involvement of prostanoids in angiogenesis
Authors: Spisni Enzo , Tomasi Vittorio
Published: November 2023

Studies on angiogenesis began in the seventeenth century when Marcello Malpighi in Bologna described the development of the chick embryo. Figure 22.1 is an original drawing from Malpighi’s book De Formatione Pulli in Ovo, as reported by Adelmann (1). Leighton, and later Folkman and collaborators, have used the chick chorioallantoic membrane (CAM) as a powerful tool with which to study the regulation of angiogenesis in vivo. (see Chapter 2).
The Biology of the Deep Ocean
Authors: Herring Peter
Published: November 2023

The deep ocean environment is the most extensive on our planet. Its denizens are normally unseen but whenever they are exposed to view they are regarded as bizarre aliens from a different world. The Biology of the Deep Ocean takes a close look at this apparently hostile world and explains how its inhabitants are exquisitely adapted to survive and flourish within it. The book begins with an analysis of how conditions in the oceanic environment differ from those in the familiar terrestrial world and then describes the techniques (and ingenuity) required to reveal the populations inhabiting the colossal volume of the deep oceans. A section on primary production emphasizes how almost all deep-sea life depends ultimately on the phytoplankton at the surface and the export flux to deeper water. The ultimate beneficiaries of this export, the populations on the deep-sea floor, are then discussed, together with the unique features of life fuelled by chemosynthesis at hydrothermal vents and cold seeps. The horizontal and vertical distribution patterns of deep-sea animals, and their changes in time and space, are controlled by physical, biological and historical factors. The rapid reduction of biomass with depth puts a high priority on efficient prey capture and energy conservation. Chapters on energy efficiency, mechanoreception, chemoreception and vision reveal the extraordinary adaptations necessary for success. Accounts of the effector systems involved in colour, camouflage and bioluminescence heighten the concept of a different world. A chapter on animal life styles emphasizes the links between size, sex, and seasonality, visible in the contrasting benefits of gigantism, dwarf males and the ability to respond to a periodic influx of food from the surface. The final chapter and appendix deal with the unique and exciting variety of life in the deep ocean, formalized as biodiversity. Its different expression on the sea floor and in midwater invites both comparisons with the rain forest and concerns about its fragility, taking the reader back to the emphasis in the first chapter on how little we still know about this critical habitat. The Biology of the Deep Ocean complements the two companion volumes on the biology of littoral and estuarine habitats and is designed to be accessible to all marine scientists, student and professional.
Geographical distribution and ecology
Authors: Tinsley R C , Loumont C , Kobel H R
Published: November 2023

Extant Xenopus species principally show a parapatric distribution; many species occupy very large distinct regions of Africa in an exclusive manner, whilst others have limited ranges. Some recently described species have been identified in samples from restricted localities and their geographical ranges are generally ill defined. In contrast to the detailed laboratory studies based on other aspects of Xenopus biology, there have been few field investigations and most ecological information is based on inference. For several species, ecological preferences emerge from their geographical distribution: thus, X. tropicalis, epitropicalis and certain species of the fraseri group are more or less restricted to lowland rain forest, whereas X. muelleri is adapted to hot, dry lowland outside the zones of rain forest and wooded savanna. This ecological restriction is particularly well illustrated for the eastern population of muelleri whose range lies below 800 m and may be limited by competing species at higher altitudes, and whose southern extension ends at the 18 °C isotherm. While the mutual laevis-muelleri exclusion in south-eastern Africa could result from the temperature requirements of X. muelleri, X. laevis does not seem to be limited by a reciprocal temperature preference since it occupies niches in Namibia and Namaqualand at least as hot as X. muelleri inhabits in the east. The northernmost limit of laevis is at Jebel Marra, within the muelleri zone of the southern Sahara, where laevis may have been isolated after a previous pluvial period.
Reproductive capacity of experimental Xenopus gilli x X. I. laevis hybrids
Authors: Kobel Hans Rudolf
Published: November 2023

Hybridization between X. I. laevis and the rare X. gilli represents an additional threat to the latter species whose geographical range is restricted to a small coastal strip from the Cape Peninsula to Cape Agulhas, South Africa. Laboratory studies on the reproductive capacity of experimental hybrids between the two species revealed that male F1 hybrids are sterile because of failure of meiotic chromosome pairing and subsequent univalent meiosis. Female F1 hybrids produce two egg types: small eggs issue from normal oocytes and big eggs from polyploidized oocytes. While the former are aneuploid because of univalent meiosis and give lethal embryos, big endoreduplicated eggs contain complete chromosome sets of both parental species. After fertilization with spermatozoa of either species, they develop into triploid females that again may produce the two egg classes.
Sexual differentiation in Xenopus laevis
Authors: Kelley Darcy B
Published: November 2023

During primary sexual differentiation in Xenopus laevis, the initially ‘indifferent’ gonads develop as testes or ovaries. Males can be functionally sex-reversed by the administration of the ovarian steroid hormone oestradiol during the early stages of gonadal differentiation (tadpole stages 54 to 66). Females can be functionally sex-reversed by the implantation of a testis during this time; administration of the testicular steroid testosterone does not result in gonadal masculinization. The sexes of progeny from crosses of sex-reversed frogs suggest that males are the homogametic (ZZ) and females the heterogametic sex (ZW); individuals whose inferred genotype is WW are female.
The Biology of Streams and Rivers
Authors: Giller Paul S , Malmqvist Björn
Published: November 2023

Although they constitute less than 1% of the world's water, freshwaters play a vital role in life on Earth. Running water, or lotic, habitats comprise a tiny proportion of these freshwaters, yet they offer important resources and are rich and complex environments. This book provides an essential introduction to the biology and ecology of lotic habitats, and their constituent organisms. Rarely has the breadth and complexity of all aspects of the biology of streams and rivers been dealt with in a single volume. The aim of this book is to delve into the rich and growing literature, and to provide an up-to-date introduction to stream and river biology. It begins by outlining the factors that make running water habitats unique, and describing the many different water-course systems. The authors then outline the range of living organisms in lotic habitats, and the environmental adaptations they exhibit. They discuss population, community, and ecosystem patterns and processes, such as energy flow, nutrient cycling, migration, food webs, and community structure. Each chapter includes practical information on simple studies and experiments for students to try. The book finishes with a discussion of applied issues surrounding water use, pollution, species diversity, and conservation of this fascinating and immensely important habitat.
An overview of venomous snake evolution
Authors: Underwood Garth
Published: November 2023

Scolecophidians have serous as well as mucous supralabial glands, but do not otherwise foreshadow later developments. Remaining snakes are primarily of secretive or burrowing nocturnal habits with a simple duplex retina (with rods and small single cones), mucous labial glands and serous superior and inferior rictal glands, opening into the corner of the mouth. They have limited mobility of the jaws and use constriction to subdue large prey of small diameter. Phisalix reports superior rictal glands to be toxic; perhaps they have a defensive function. Amongst erycines, boines, pythonines, tropidophines and bolyerines the rictal glands regress; they are able to swallow bulky prey, subdued by constriction.
Reef Evolution
Authors: Wood Rachel
Published: November 2023

Reefs are an extraordinary natural phenomenon. Visible from outer space, coral reefs are the largest biologically constructed features known; in close proximity their spectacular beauty and abundance of life is dazzling. Reefs are estimated to occupy only a small percentage of the oceans, but their importance to the marine environment is many-faceted and global. Reefs create harbours and allow the development of shallow basins with associated mangrove or seargrass communities; they protect coastlines from erosion; reefs are involved in the regulation of atmospheric carbon, which in turn contributes to climate control; ancient reefs can provide extensive oil and gas reservoirs. From a biological standpoint, however, the great significance of reefs lies in their ability to generate and maintain a substantial proportion of tropical marine biodiversity. This text documents those biological innovations which have moulded the evolution of reef ecosystems and given rise to the highly complex communities found today. The appearance of clonality, the acquisition of photosymbiosis and the radiation of predator groups are all discussed in depth. Throughout the book, Rachel Wood uses data from the fossil record to document the evolutionary development of reef ecosystems. This interdisciplinary approach has the aim of providing an analytical text which will be of value not only to advanced undergraduates and postgraduate courses, but also to researchers in ancient reef ecology. Rachel Wood is Royal Society University Research Fellow, and Fellow, Gonville and Caius College, Cambridge.
The record: ancient reef ecologies
Authors: Wood Rachel
Published: November 2023

Reefs have existed since the appearance of microbial mat communities over 3.5 billion years ago. Since that time, many groups of extinct and extant skeletal algae and metazoans as well as microbes have aggregated to form a tremendous variety of reef ecologies in widely differing environmental settings.
Atoms in Molecules
Authors: Bader Richard F W
Published: November 2023

The molecular structure hypothesis - that a molecule is a collection of atoms linked by a network of bonds - was forged in the crucible of nineteenth-century experimental chemistry and has continued to serve as the principal means of ordering and classifying the observations of chemistry. There is a difficulty with the hypothesis, however, in that it is not related directly to the physics which governs the motions of the nuclei and electrons that make up the atoms and the bonds. It is the purpose of this important new book to show that a theory can be developed to underpin the molecular structure hypothesis - that the atoms in a molecule are real, with properties predicted and defined by the laws of quantum mechanics, and that the structure their presence imparts to a molecule is indeed a consequence of the underlying physics. As a result the classification based upon the concept of atoms in molecules is freed from its empirical constraints and the full predictive power of quantum mechanics. As a result the full predictive power of quantum mechanics can be incorporated into the resulting theory - a theory of atoms in molecules. The book is aimed at those scientists responsible for performing the experiments and collecting the observations on the properties of matter at the atomic level, in the belief that the transformation of qualitative concepts into a quantitative theory will serve to deepen our understanding of chemistry.
Chemical Models And The Laplacian Of The Charge Density
Authors: Bader Richard F W
Published: November 2023

The 1916 paper of Lewis, introducing the concept of the electron pair, is one of the most important papers to be published in chemistry in this century. It is a revelation to read this paper and realize the extent to which his ideas continue to dominate chemical thinking. One must marvel at the intuitive leap that was involved in advancing the notion of the importance of the electron pair, coming as it did before the development of quantum mechanics or the still later introduction of the concept of electron spin. Indeed the opening quotation from the paper by Lewis was penned in response to Bohr’s then recently advanced mechanical model of the atom. So strong was his conviction regarding the existence of a closely coupled pair of electrons (we would say a localized pair) as being necessary for the understanding of chemical bonding, he felt forced to postulate the failure of Coulomb’s law for small interelectronic separations, and to thus necessarily reject any model which made use of this law. It is clear from the quotation given at the beginning of Chapter 5 that Lewis later (1933) abandoned this extreme position.
Scientific work in the 1880s
Authors: Kipnis A Ya , Yavelov B E , Rowlinson J S
Published: November 2023

At the meetings of the Section of Sciences in October and November 1880 he set out a fruitful development in molecular physics called the principle (or law) of corresponding states [12aci]. Two substantial papers in Dutch were published the same year [12,15]. Roth worked quickly; abstracts appeared in the Beibliitter in January and April 1881, and complete and even extended translations were incorporated into the German version of Continuity. Roth, one of the most active contributors to the Beibliitter, was for many years almost a ‘personal abstractor’ of van der Waals’s work, and even drew atten tion to it in his abstracts of other papers in the field [3]. Van der Waals arrived at the principle of corresponding states by analysing the transition from gas to liquid represented by the loops in his isotherms, that is the curve Bcdefgh in Fig. 3.2. These loops are unobservable and the experimental points lie on the horizontal line CG. At what pressure must this line be drawn? In 1873 he had ‘not had the good fortune to solve this important problem.... I have not succeeded in finding, in any of the properties of the saturated vapour, a characteristic one that I could use to determine where this line must be drawn through the isotherm’ [le2, p. 232,233].
Inclusion of ions and neutral molecules in calixarenes
Authors: Andreetti Giovanni D , Ugozzoli Franco , Ungaro, Rocco , Pochini Andrea
Published: November 2023

The design and synthesis of molecular systems which perform chemical, physical, and biomimetic transformations with high efficiency and selectivity, and the understanding of the factors which determine the selective molecular recognition are two of the major aims of host-guest or supramolecular chemistry. In this novel multidisciplinary research area there is a continuous need for new building blocks, shaping units, or substructures which can be easily functionalized to build up more complex structures able to perform a particular transformation. Since the pioneering work of Gutsche and Muthukrishnan, Gutsche et al., and ourselves, which was mainly devoted to establishing the structures of the cyclic products formed by the base-catalyzed condensation of phenols and formaldehyde, the calixarenes (1)-(4) (see the preceeding chapter by Gutsche) have become rather popular among the chemical community.
Solid state Nmr studies of inclusion compounds
Authors: Ripmeeste J A , Ratcliffe C I
Published: November 2023

In the last review of solid state NMR as applied to clathrates,1 the emphasis was on clathrate hydrate work, with smaller contributions from studies on quinol and other clathrates. This time again clathrate hydrates are prominent, as these materials are perhaps the simplest and best understood of the clathrates. Since much work has been carried out on the channel inclusion compounds (urea, thiourea, cyclopho’ Sphazene, deoxycholic acid) these are also reviewed. For the sake of completeness, earlier work on these materials has also been summarized. Other host materials reviewed include cyclodextrins, tri-o-thymotide, and Dianin’s compound.
How do they do it?—Coping with oxygen
Authors: Milgrom Lionel R
Published: November 2023

Oxygen is a gas. Colourless and odourless, without it we suffocate. Yet when its partial reduction products, hydroxyl radicals and peroxy radicals, ovenvhelm our body’s defence systems, oxygen ultimately kills us. It is these partial reduction products that are the most likely cause of ageing.
On the use of the fast rotation function
Authors: Alzari P M , Navaza J
Published: November 2023

The widespread use of molecular replacement techniques in protein crystallography is a result of the significant number of known three-imensional structures now available in the Protein Data Bank. These techniques are used almost without exception whenever a known structure for a closely homologous molecule to the one under study is available. Positioning of a molecular model in the unit cell involves the determination of both orientation and translation parameters. As a general rule, the orientation is first determined using Patterson search methods. A relatively precise solution of this problem is crucial for the success of the subsequent translation search.
Density modification: theory and practice
Authors: Podjarny A D , Rees B
Published: November 2023

Real space phasing methods are aimed at improving the agreement of a density map with a set of physically meaningful constraints. Density maps must agree simultaneously with experimental data such as the observed amplitudes and the MIR phase distribution and with physical constraints based on a-priori knowledge of the characteristics of the density function. These physical constraints include positivity; boundedness; electron density histogram; high-resolution atomicity; uniformity of solvent regions; continuity of the bio-polymer chain; and known NCS of the density distribution. A starting map to be processed by real space methods, such as an MIR map, is usually obtained from, and thus will fully agree with, the experimental data. If the map also agrees with the set of physical constraints, there is no room for real space techniques, and map interpretation should be attempted. It is more often the case, however, that the map does not fully agree with all the physical constraints. In this case there is room to improve the agreement by real space techniques. To impose the physical constraints on an experimental map, a “Density Modification (DM)* iterative algorithm has been proposed [1,2]. It alternates real and reciprocal space operations, and the procedure is outlined in the flowchart shown in figure 1, with the following steps:
Tin-based antitumour drugs: past, present, and future
Authors: Gielen M , Meriem A , Boualam M , Delmotte A , Willem, R , Vos D de
Published: November 2023

The screening results obtained on the antitumour activity of several series of diorganotin compounds against L1210, P388, and P815 cancer cells in mice are reviewed, and perspectives for future research in this area delineated.
Solid/liquid equilibrium
Authors: Koningsveld R , Stockmayer W H , Nies E
Published: November 2023

Polymers with sufficiently regular chain structures can exist in the crystalline state, and departures from regularity reduce the stability (and hence the melting points) of polymer crystals. For example, ‘high-density’ polyethylene, produced with the aid of organometallic coordination (Ziegler type) catalysts, typically melts at around 135 °C, while the low-density polymer produced by high-pressure free-radical polymerization melts at ≤125 °C because that process introduces chain branching. Highly isotactic polystyrene has a crystalline melting point of about 230 °C, but ordinary atactic (actually slightly syndiotactic) polystyrene does not crystallize at all.
Introduction
Authors: Ernst Richard R , Bodenhausen Geoffrey , Wokaun Alexander
Published: November 2023

In the course of the last two decades, nuclear magnetic resonance (NMR) has gone through a profound renaissance. Slow-passage spectroscopy techniques have largely become obsolete, and more versatile pulse techniques have begun to dominate the NMR scene. The rediscovery of the time domain has revived interest and stimulated creativity for new methodological developments. A surprising diversity of novel approaches and ingenious procedures has been invented and has radically changed the scope of NMR spectroscopy.
The Dynamics of Nuclear Spin Systems
Authors: Ernst Richard R , Bodenhausen Geoffrey , Wokaun Alexander
Published: November 2023

The dynamics of isolated spins can be understood in terms of the motion of classical magnetization vectors (see §4.2). To describe coupled spins, however, it is necessary to have recourse to a quantum mechanical formalism where the state of the system is expressed by a state function or, more generally, by a density operator. In this chapter, we give a condensed account of the density operator treatment, in particular of those aspects which are relevant to pulse experiments in liquids and solids. The equation of motion of the density operator is introduced in §2.1.
Quantum Description of High-Resolution NMR in Liquids
Authors: Goldman Maurice
Published: November 2023

Available in paperback for the first time, this book describes the main methods of one- and two-dimensional high-resolution NMR spectroscopy in liquids within the quantum-mechanical formalism of the density matrix. In view of the increasing importance of NMR in chemistry and biochemistry, it is particularly addressed to those scientists who do not have a working knowledge of quantum calculations. This knowledge is provided in the first part of the book through a description of quantum mechanics as applied to spin systems: this description is both self-contained and limited to the essentials. A final chapter is devoted to the principles of relaxation theory. The book will endow the reader with enough practice in the theoretical tools of NMR to enable him to analyse critically comprehensive treatises or articles on new methods.
Asymmetric conjugate addition
Authors: Alexakis A
Published: November 2023

The conjugate addition, the most popular reaction in organocopper chemistry, is very well suited for the formation of new stereogenic centres. Several examples of very high levels of diastereoselectivity show that organocopper reagents are very sensitive to the steric and electronic environment of the prochiral sp2 carbon β to the carbonyl. Owing to the importance of this synthetic transformation it is not surprising that the asymmetric version of this reaction was attempted at the very early stages of the organocopper era. There are several ways to attain this goal. The most obvious one is to attach covalently a chiral auxiliary, do a diastereoselective conjugate addition, and then remove this chiral auxiliary, the overall result being an enantioselective transformation. This chiral auxiliary may be placed either on the electrophile or on the R group of the organocopper reagent itself.
Preparation of Alkenes
Authors: Williams Jonathan M J
Published: November 2023

Alkenes represent an important structural target for organic chemists. From the large scale synthesis of simple alkenes through to the small scale synthesis of densely functionalized molecules which contain an alkene subunit, the chemical literature contains many examples of alkene synthesis. This laboratory handbook provides useful practical procedures for many of the more widely used alkene syntheses. Individual authors have shared their experiences of alkene synthesis to provide guidance and practical advice to the novice and expert alike.

Preparations of alkenes: a practical approach not only provides detailed practical procedures, but also clearly reviews important developments in this area. Additionally, an extended summary enables the reader to find out which methods are most suitable for particular classes of alkene, including mono-substituted, (E)- or (Z)- di-substituted, tri-substituted, cyclic, and heteroatom-substituted alkenes.
The Wittig reaction and related methods
Authors: Lawrence Nicholas J
Published: November 2023

The Wittig reaction, the reaction of an a-phosphorus estabilized anion with a carbonyl derivative, is undoubtedly one of the most useful methods for selectively constructing carbon-carbon double bonds. This is for many reasons: the precursors are easily prepared and in many instances are available readily, the reaction is high yielding, the alkene is specifically positioned, and in many instances is stereoselective. Wittig developed the reaction of phosphoniumylides with aldehydes in the early 1950s.
Non-phosphorus stabilized carbanions in alkene synthesis
Authors: Armstrong Alan
Published: November 2023

Foremost amongst the methods available to the synthetic chemist for the preparation of alkenes is the reaction of carbanions a- to phosphorus with carbonyl compounds (the Wittig reaction and its variants; Chapter 2). The essential principles of the Wittig reaction-the stabilization of a carbanion by the phosphorus atom, reaction of this carbanion with a carbonyl compound, and subsequent elimination-can be extended to the use of anions stabilized by other, non-phosphorus heteroatoms (Scheme 3.1). This chapter will consider alkene formation involving carbanions stabilized by trialkylsilyl groups (Peterson olefination), sulfoximines (Johnson methylenation), sulfones (Julia olefination), and boron. These methods can offer useful alternatives to phosphorus-based olefinations, particularly in terms of ease of isolation of the product and, importantly, in the control of alkene stereochemistry.
Reduction of alkynes
Authors: Howarth Joshua
Published: November 2023

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Catalytic coupling reactions
Authors: Reiser Oliver
Published: November 2023

Palladium- and nickel-catalyzed coupling reactions have become a powerful method for the functionalization of alkenes and arenes. There is a broad variety of different reactions to choose from, which in many cases can be used to reach the same synthetic end-point. Moreover, in recent years many different procedures for each type of reaction have been published, making it even more difficult to choose the right procedure for a particular synthetic problem. The following chapter will provide the reader with procedures that are applicable to a large number of substrates. Nevertheless, if a protocol should not work for a specific case, it might be worth changing the reaction conditions—even if this change appears to be rather small—since palladium-and nickel-catalyzed reactions are quite sensitive towards parameters such as the palladium source, ligand, base, solvent, temperature, and substrate.
Techniques for the study of physical properties
Authors: Besson J M
Published: November 2023

Electrical measurements are among the most ancient methods used to characterize samples at high pressures. Indeed, before the advent of diamond-anvil cells (DACs), they were the most often used characterization methods in belt-type or multianvil devices at pressures above 2 GPa for the detection of solid-solid phase transitions—upon which the so-called fixedpoint pressure scale was based (see Section 2.2 in Chapter 2).