bluuebunny/crossref_metadata_2025 huggingface dataset:
Fine chemicals manufacture
Authors: Whyman Robin
Published: September 2023

This chapter refers to the advantages to be derived from the use of homogeneous catalysts which concerns high selectivities. These advantages may be achieved in a wide range of chemical transformations. It reviews a mechanistic understanding of homogeneous catalysis which has developed to an increasingly sophisticated level. It also discusses the extent of the progress of successful applications of homogeneous catalysis in the manufacture of commodity chemicals and polymer intermediates for the production of fine chemicals. The chapter analyzes the application of organometallic chemistry and homogeneous catalysis, both of which can lead to economically viable alternative process routes that eliminate steps in the traditional and costly multi-stage procedures. The chapter reviews the ultimate application of high selectivities which concerns the development of catalysts for the synthesis of chiral compounds with high degrees of enantioselectivity.
Inorganic Chemistry in Biology
Authors: Wilkins Patricia C. , Wilkins Ralph G.
Published: September 2023

Inorganic Chemistry in Biology describes the importance and impact of a number of elements, other than carbon, in biological chemistry. There is a short background describing the interaction of inorganic molecules, especially metal ions, with biomolecules. The major part of the book contains a survey of biologically important elements and briefly includes the roles played in such varied species as humans, crocodiles, chickens, fish, beetles and plants and in diseases such as cystic fibrosis, methemoglobemia, and thalassemia.
The composition of metallobiomolecules
Authors: Wilkins Patricia C. , Wilkins Ralph G.
Published: September 2023

This chapter focuses on the make-up of the metallobiomolecule, particularly the portion in which the metal ion resides. It talks about the rules that govern structures of biomolecules that are much the same with or without a metal ion, although there can be significant perturbations due to the presence of the metal. It also discusses the metal-ligand bond which is central to many aspects of the behaviour of metallobiomolecules. The chapter covers the metalloproteins and metal complexes of biologically important materials and the metal ion that is attached to the ligands by nitrogen, oxygen, or sulfur donor atoms. It mentions the number of donor atoms that are bound to the metal ion and constitutes the coordination number.
Stereoselectivity in Organic Synthesis
Authors: Procter Garry
Published: September 2023

Stereoselectivity in Organic Synthesis is concerned with the reactions used in stereoselective organic synthesis. It sets out to consider the general principles upon which such reactions are founded, especially stereoelectronic effects, and how these are applied to a wide range of stereospecific and stereoselective organic reactions used in organic synthesis today. The general topics covered include: reactions of carbonyl compounds, aldol reactions, additions to C-C double bonds, oxidation and reduction, rearrangements, and enzyme catalyzed hydrolysis. Reactions whose stereoselectivity is either substrate controlled, reagent controlled or controlled by a catalyst are covered, and where appropriate, examples of their application in organic synthesis are provided.
Additions to carbonyl
Authors: Procter Garry
Published: September 2023

This chapter examines additions to carbonyl compounds, which is one of the most important reactions in organic synthesis. Nucleophilic additions to carbonyl groups can be divided into those which give enantiomeric products, and those whose products are diastereoisomers. In the latter case, the carbonyl compound is often chiral. The chapter then looks at additions to chiral carbonyl compounds and prochiral carbonyl compounds. There have been several models advanced to account for the trends observed in the diastereoselectivity of nucleophilic additions to ketones and aldehydes. Such models need to take into account the various factors which might influence such additions. These include conformational effects, steric interactions, electronic factors, and stereoelectronic effects.
The Basis and Applications of Heterogenuous Catalysis
Authors: Bowker Michael
Published: September 2023

The Basis and Applications of Heterogeneous Catalysis covers a wide range of topics within this field. Catalysis is one of the most important technologies in our modern world. We depend on it to produce materials, such as plastics, from oil; we depend on it to produce fuel to power our cars; we depend on it to remove the pollutants emitted from the engines of those cars; we even depend on it for the functioning and growth of our own bodies. It is therefore highly important that we ask ourselves the question, 'What is catalysis?' This book does exactly that, concentrating on the most important type of catalysis for industry, namely heterogeneous catalysis. The book is split into three sections, dealing with the fundamentals of adsorption and reaction at surfaces, the nature of heterogeneous catalysts and their synthesis, and the applications of this technology in the modern world.
Core Carbonyl Chemistry
Authors: Jones John
Published: September 2023

Core Carbonyl Chemistry starts with an introduction to the main themes in this topic. The first chapter covers nucleophilic reagents, aldehydes, and kenotes. There follows a chapter on acetals and ketals. The text also covers reactions of amino compounds with aldehydes and ketones, reactions of nucleophiles with carboxylic acid esters, and reactions of nucleophiles with other carboxylic acid derivates. There are also chapters on enols and enolates, and enolate allylations. Finally, the text looks at aldol condensations and related reactions.
Introduction: the main themes
Authors: Jones John
Published: September 2023

This introductory chapter provides an overview of the carbonyl group, which is the commonest reactive component of organic structures. In carbonyl compounds, both the carbon and oxygen atoms are sp
2 hybridized, with the σ-bonds to carbon and the oxygen lone pairs coplanar. As the electronegativity of oxygen is greater than that of carbon, the carbonyl group is polarized, with the carbon atom positively charged relative to the oxygen, so that the carbon atom is electron-demanding. All the reactions of carbonyl compounds discussed in this book involve electron-supply to the electron-demanding carbon as a key feature. Such electron-supply can be achieved by either nucleophilic attack or ionization at a contiguous centre.
The addition of nucleophilic reagents to aldehydes and ketones
Authors: Jones John
Published: September 2023

This chapter discusses the addition of nucleophilic reagents to aldehydes and ketones. In the series formaldehyde–acetaldehyde–acetone, reactivity to nucleophiles decreases in that order. The electronic factor here is deactivating, but slight, because the additional Me groups are not attached directly to the carbonyl carbon. They are largely insulated from it by saturated carbon atoms. The chapter then considers high degrees of hydration at equilibrium, which generally result when the carbonyl group has strong electron-withdrawing substituents attached, and in extreme cases it is the hydrate which is the familiar form of the carbonyl compound. It also looks at hemiacetal and hemiketal formation; cyanohydrin formation; bisulfate addition; the Meerwein–Ponndorf–Verley reaction; the Cannizzaro reaction; and reaction with Grignard reagents.
Aldol condensations and related reactions
Authors: Jones John
Published: September 2023

This chapter explores aldol condensations and related reactions. The reactions of enols and enolates with electrophiles are not confined to the simple α substitutions so far discussed. The electrophile can also be a carbonyl compound, and, as with the attack of simpler nucleophiles on carbonyl groups, the formation of a tetrahedral adduct can be followed by protonation, dehydration, or loss of a leaving group. Aldol condensations, whether carried out with acid or base catalysis, are often followed by spontaneous dehydration. Dehydration is practically the norm for acid-catalyzed conditions. The chapter then looks at crossed aldol condensations; enolate acylation reactions; the Thorpe–Ziegler cyclization; and αβ unsaturated carbonyl compounds.
Radiation
Authors: Winterton R. H. S.
Published: September 2023

This chapter discusses radiation. Heat transfer by radiation requires no physical medium. It is most effective in a vacuum and is electromagnetic in nature. With this definition in mind, the chapter embarks on the usage of black bodies in heat transfer by radiation. The chapter then considers real surfaces, which display a number of features absent in the idealized black surface. Next, this chapter takes a look at view factor — the fraction of the energy transferred from one surface to another — and its general formula. It also uses view factor to discuss heat exchange between grey bodies as well as electrical analogy.
Chemical Reaction Engineering
Authors: Metcalfe Ian S.
Published: September 2023

Chemical Reaction Engineering
covers the material required for a basic understanding of chemical reaction engineering. The first chapter introduces the topic. The next chapter considers the materials balance for chemical reactions. The chapter after that examines the calculation of reactor volume and residence time. The chapter that follows is about multiple reactions. The text also covers the energy balance and temperature effects. The last chapter is about non-ideal reactors.
Introduction
Authors: Metcalfe Ian S.
Published: September 2023

This introductory chapter outlines the scope and objectives of this book, and provides an overview of the knowledge required. This book is primarily intended for readers who have already taken a basic course in chemical kinetics. The reader should also have some knowledge of thermodynamics for an appreciation of reaction equilibria, heats of reaction, and energy balances. When material and energy balances for batch, CSTR, and PFR reactors are performed, reaction rate expressions will be required in an algebraic form. Reaction rate is usually expressed in terms of the concentrations or partial pressures of the reactants (and sometimes products) and may be determined empirically or may, in part, be based upon an understanding of the reaction mechanism. Ultimately, this book offers knowledge of the principles of chemical reaction engineering which will enable the reader to design basic chemical reactors.
The energy balance and temperature effects
Authors: Metcalfe Ian S.
Published: September 2023

This chapter demonstrates how reactors need not be isothermal. It looks at how reaction rate depends upon temperature for different classes of reaction, including irreversible reactions, reversible endothermic reactions, and reversible exothermic reactions. The chapter then formulates the energy balance for given reactors and uses this to investigate the variation of temperature and therefore reaction rate with time or position in the reactor. This, in turn, can be used to calculate reactor volumes and residence times for a given duty. The chapter also considers steady-state multiplicity in continuous stirred tank reactors (CSTRs) and multistage adiabatic plug flow reactor (PFR). For a PFR, there exists an optimum temperature profile or line of maximum reaction rate and it is important to try to approach this path. The chapter discusses two different methods for achieving this: interstage cooling and cold-shot cooling.
d-Block Chemistry
Authors: Mark J. Winter
Published: September 2023

d-Block Chemistry begins with a chapter which introduces the topic as a whole. The next chapter covers complexes. The chapter that follows considers shape and isomerism. The fourth chapter looks into metal classification and electron counting. The next chapter covers an ionic model of metal complexes. There follows chapters on covalent models of metal complexes and the consequences of d-orbital splitting. The final chapter looks at formulae and nomenclature.
Introduction
Authors: Mark J. Winter
Published: September 2023

This chapter focuses on d-block elements, which are the forty elements contained in the four rows of ten columns in the periodic table and are identified as the transition metals. It discusses the term transition element or transition metal. The term transition element derives from early studies of periodicity, as shown by the Mendeleev periodic table of the elements. The chapter also addresses some aspects of f-block elements where it is useful to make comparisons with the d-block metals. The chapter emphasizes the chemistry of the d block metal compounds. This is central to diverse areas, including analytical chemistry, inorganic chemistry, organic synthesis, catalysis, and metal extraction. The chapter describes the first row d-block elements as biologically necessary trace elements.
Shape and isomerism
Authors: Mark J. Winter
Published: September 2023

This chapter describes an array of structural types available for metal complexes and well-known algorithms for the prediction of geometry in p-block chemistry, such as the VSEPR predictive rules. It talks about a d-block metal that has nine valence atomic orbitals, which are either used to form bonds with ligands or are nonbonding. It also examines the number of coordinated ligand atoms that governs the arrangement of ligands around the metal within a complex. The chapter discusses the geometry of most coordination complexes wherein the ligands are as far apart as possible from each other. It highlights the possibility of higher coordination numbers for the metals in the early second and third series, such as metals within the f-block that display higher coordination numbers.
X-ray crystallography in practice
Authors: Clegg William
Published: September 2023

This chapter highlights the various steps of a typical crystal structure determination, and describes a number of commonpotential problems together with ways of dealing with them. It shows an outline of crystal structure determination in a simplified form known as a schematic flowchart. It also analyzes the intensities of X-rays diffracted by a crystal that depend on the crystal size, unit cell volume, and types and numbers of atoms in the unit cell. The chapter talks about diffracted intensities that are directly proportional to the crystal volume and the absorption of X-rays by crystals, which increases exponentially with crystal dimensions. It explains how the amount of absorption depends on the X-ray wavelength and on the chemical composition.
NMR experiments
Authors: Hore P.J
Published: September 2023

This chapter explains how nuclear magnetic resonance (NMR) experiments work. Modern NMR spectroscopy is much more than simply recording a spectrum and interpreting the positions, widths, and intensities of the lines. The spins can be manipulated to tailor the information that appears in the spectrum. The chapter begins by introducing the 'vector model'. Although it has its origin in the quantum mechanics of spin angular momentum, it has the distinct advantage of being pictorial and essentially non-mathematical. The disadvantage is that it only helps us to understand the simplest NMR experiments. The chapter then uses the vector model to discuss two techniques for measuring spin relaxation times and an important method for sensitivity enhancement (Insensitive Nuclei Enhanced by Polarization Transfer or INEPT).
Sexual Selection
Authors: Bell Graham
Published: September 2023

This chapter examines sexual selection. Like all other mammals, we are each male or female, and both must participate to produce offspring. Many other species, however, regularly reproduce with no appearance of either sex or gender. Sex is associated with reproduction in species like our own, but it is certainly not necessary for it. So why does it exist? The chapter looks at how the eukaryote life cycle is an alternation between vegetative and sexual cycles. It then considers how sex modulates the dynamics of evolution, and how gametes are modified by sexual selection. Finally, the chapter discusses how males and females are divergently specialized through sexual selection.
Human Virology
Authors: Oxford John , Kellam Paul , Collier Leslie
Published: September 2023

Human Virology is made up of three parts. Part 1 looks at general principles in virology, including viral replication and genetics, how viruses cause disease, and epidemiology. Part 2 is about specific viruses, including positive-sense single-stranded RNA viruses such as coronaviruses and astroviruses, negative-sense single-stranded RNA viruses such as bunyaviruses and filoviruses, double-stranded RNA viruses, double-stranded DNA viruses, single-stranded DNA viruses, single-stranded positive-sense RNA with an RT, and circular double-stranded DNA viruses with an RT. The final part looks at practical aspects of virology, including the clinical virology laboratory, control of viral disease by immunization, and antiviral chemotherapy.
How viruses cause disease
Authors: Oxford John , Kellam Paul , Collier Leslie
Published: September 2023

This chapter begins its explanation with photos of a child with measles, an elderly patient with severe herpes zoster, and another child with a malignant tumour of B-cells that can affect the jaw which is known as Burkitt’s lymphoma (BL). Each of these people is under attack by a virus. The chapter notes that the manifestations differ greatly, not only in appearance, but also in the way in which the viruses concerned cause these unpleasant effects. The chapter talks about measles, which is an acute infection of children. Most patients recover quite quickly and develop immunity against a second attack, while the zoster rash is caused by a reactivation of a lifelong persistent infection with a herpes virus. Lymphoma is caused by another herpes virus that has transformed immune B-cells. The chapter focuses on complex interactions between viruses and hosts that result in disease–in other words, with the pathogenesis of viral infection.
Astroviruses: gastroenteritis agents
Authors: Oxford John , Kellam Paul , Collier Leslie
Published: September 2023

This chapter looks at astroviruses, which were first identified by electron microscopists 40 years ago. These viruses are the second most common cause of gastroenteritis in young children after rotavirus. Rotavirus may often be a co-pathogen, and multiple serotypes circulate simultaneously, especially in developing countries. The chapter elaborates that these viruses spread by the faecaloral route and cause gastroenteritis in animals such as calves, piglets, dogs, cats, and mink. The family name is derived from the negative contrast EM of astroviruses in which the exterior surface of a small rounded 30-nm icosahedral non-enveloped virion has a curious five- or six-pointed star appearance. The chapter looks at more recent three-dimensional views of the virion that have been constructed by a combination of cryo-electron microscopy and electron density maps.
Reoviruses: diarrhoea-causing rotaviruses
Authors: Oxford John , Kellam Paul , Collier Leslie
Published: September 2023

This chapter highlights the reoviruses, which were identified in the 1950s and were noted to cause very minimal or no disease. Scientifically they became noteworthy as the first viruses discovered to have a double-stranded RNA genome. The chapter traces the genus of the Reoviridae family. An example is the rotavirus, which was shown to be an important cause of gastroenteritis worldwide in children under the age of five. The virus causes over 500,000 deaths annually, the majority in the developing countries of Asia and Africa. The chapter explains that reo stands for respiratory enteric orphan because although they could be identified in the respiratory tract and gut, the virions were at first thought not to be associated with any disease, hence orphan.
Smallpox: human disease eradicated but zoonotic pox virus infections common
Authors: Oxford John , Kellam Paul , Collier Leslie
Published: September 2023

This chapter highlights the smallpox epic, which provides at least three firsts: the first vaccine, the first disease to be totally eradicated, and the first virus infection against which chemotherapy was clinically effective. Although the smallpox itself is now extinct, other poxviruses still infect humans, and one of them may be used in a rather surprising way to immunize against quite different diseases. The chapter mentions the threat of bioterrorism or accidental release of previously unrecognized freezer stocks, which has led some countries to stockpile vaccinia virus vaccine against smallpox. Also, safer vaccines are being developed to be held in a strategic reserve. Leslie Collier made a significant contribution to the smallpox eradication campaign by developing a new stabilizer for the vaccine to be used in tropical and temperate countries. The chapter looks at the genera of smallpox, which are distinguished on the basis of morphology, genome structure, growth characteristics, and serological reactions.
Parvoviruses
Authors: Oxford John , Kellam Paul , Collier Leslie
Published: September 2023

This chapter discusses parvoviruses, which show a degree of dependence as they can replicate only in the presence of active DNA synthesis in rapidly dividing host cells or under the influence of another virus infection. Their genome of 5kb is small but larger than hepatitis B virus (3kb) and the same size as polyomaviruses, but their DNA is single-stranded and allows compact packaging. The chapter examines the complex relationship of the parvoviruses with the host, noting that there is only restricted ability to cultivate them in the laboratory and there are no animal models. Their wide circulation and self-limiting clinical course have led to a diminished appreciation of their clinical importance. The chapter highlights the two subfamilies of Parvoviridae: Parvovirinae, which infect vertebrates, and Densovirinae, which infect invertebrates.
Introduction to Protein Science
Authors: Lesk Arthur M.
Published: September 2023

Introduction to Protein Science firstly outlines the topics ahead. The first main topic is protein structure and protein structure determination. The next subject the text considers is bioinformatics of protein sequence and structure. Proteins as catalysts is examined after that. This discussion particularly looks at enzyme structure, kinetics, and mechanisms. The text then moves on to describe proteins with partners, the evolution of protein structure and function, and protein folding and design. Finally, it looks at proteomics and systems biology.
An Introduction to Molecular Ecology
Authors: Rowe Graham , Sweet Michael , Beebee Trevor J. C.
Published: September 2023

An Introduction to Molecular Ecology first introduces the topic by looking at roots and branches, molecular biology for ecologists, and molecular tools for molecular ecologists. Next, chapters turn to the next generation sequencing, species, populations, and individuals. Chapters also look at behavioural ecology and population genetics. The text also covers neutral and adaptive molecular variation, phytogeography, and conservation genetics. Finally, chapters look at microbial ecology, metagenomics, genomes, and genomics.
Maths for Chemistry
Authors: Monk Paul , Munro Lindsey J.
Published: September 2023

Maths for Chemistry recognizes the challenges faced by many students in equipping themselves with the maths skills necessary to gain a full understanding of chemistry. Working from foundational principles, the book builds students' confidence by leading through the subject in a steady, progressive way from basic algebra to the mathematics of quantum chemistry. Opening with the core mathematics of algebra, logarithms, and trigonometry, the book goes on to cover calculus, matrices, vectors, complex numbers, and laboratory mathematics.
Trigonometry
Authors: Monk Paul , Munro Lindsey J.
Published: September 2023

This chapter provides an overview of trigonometry, starting with the process of naming a right-angled triangle. It considers the simple trigonometric functions, looking at sine, cosine, and tangent. A sine is the ratio of the length of the opposite to the length of the hypotenuse, and a cosine is the ratio of the length of the adjacent to the length of the hypotenuse. Meanwhile, a tangent is the ratio of the length of the opposite to the length of the adjacent. The chapter then discusses radians, which are a way of subdividing angles within a circle; Pythagoras' theorem, which requires a right-angled triangle; and polar coordinates, which are especially useful when considering spherical or cylindrical spaces. It also examines the cosine rule and trigonometric identities.
Differentiation IV
Authors: Monk Paul , Munro Lindsey J.
Published: September 2023

This chapter discusses the product rule and the quotient rule. The word ‘product’ comes from productum, which means a ‘mathematical quantity obtained by multiplication’. Meanwhile, the word ‘quotient’ comes from quotiens, which means the ‘number of times one quantity is contained in another’. We often see the product rule written without multiplication signs or brackets. The strong symmetry within the equation may help us to remember it. The chapter then explains how a quotient takes the form of a fraction with one function divided by another. We first analyse the two functions before using the quotient rule. The final answer can usually be simplified further, e.g. by factorizing.
Graphs I
Authors: Monk Paul , Munro Lindsey J.
Published: September 2023

This chapter begins by explaining the concepts underlying graphical representations. Scientists often want to know if a relationship exists between pairs of variables. A graph is one of the better ways of discerning if a relationship exists and the nature of that relationship. For chemists, the most common graphical method is the Cartesian graph. The x-axis is the horizontal axis and represents the controlled variable. Meanwhile, the y-axis is the vertical axis and represents the observed variable. The chapter then considers how plotting a graph is one of the best ways to discern the quantitative relationship(s) between the observed and controlled variables. It also looks at the correct appearance of a graph, before discussing inflections, asymptotes, and sigmoidal graphs.
Probability I
Authors: Monk Paul , Munro Lindsey J.
Published: September 2023

This chapter focuses on probability, which is defined in terms of the number of possible outcomes. To be meaningful, we need a range of possible outcomes and can describe each outcome with a numerical value. A probability P of 1 implies that an event is certain to occur, while a probability P of 0 implies that an event is certain never to occur. The chapter then looks at simple calculations with probability, before explaining the concept of bias. Bias implies that something has intervened. Removing all bias is thus a major task for all analyses relying on probability. Finally, the chapter considers the probability of a sequence or a number of consecutive occurrences, which is a product of the probabilities of the individual events.
Probability II
Authors: Monk Paul , Munro Lindsey J.
Published: September 2023

This chapter assesses partition functions and wavefunctions. Probability is best treated statistically when we deal with a vast number of particles. Statistical probabilities are usually considered in terms of a certainty or a proportion rather than simpler probabilities. The chapter then looks at the Boltzmann distribution, which describes the population of the energy levels which has the greatest weight and therefore the highest probability. We can further simplify the Boltzmann distribution by writing it in terms of the molecular partition function. The chapter also considers equilibrium constants, residual entropy, quantum mechanics, and tunnelling probability. Quantum tunnelling can occur when a particle tunnels through an energy barrier that classical mechanics would prevent.
Dimensional analysis
Authors: Monk Paul , Munro Lindsey J.
Published: September 2023

This chapter focuses on dimensional analysis, which represents a way of looking at the units of an equation. Analysing the units in an equation is a simple and efficient way of testing whether an equation is correct. The chapter then looks at the Système Internationale (SI) system, which was designed in such a way that all units and definitions are self-consistent. The system comprises seven so-called base units (or fundamental units). The SI system lets us bolt together multiples of these seven base units to assemble the units of all the other parameters in mathematics, physics, chemistry, engineering, and other numerate disciplines. The chapter also considers quantity calculus, which tells us how to handle physical quantities and their units using the normal rules of algebra.
The cervical screening process
Authors: Crossley John , Crossley Beverley
Published: September 2023

This chapter explores the purpose and aims of cervical screening. It introduces issues related to the success of screening and states that this success depends upon high coverage, cost effectiveness, proven methods of treatment or counselling, and a test that is reliable with a high sensitivity and high specificity. It discusses the National Health Service Cervical Screening Programme (NHSCSP), which aims to reduce the incidence and mortality of cervical cancer by detecting and treating potentially precancerous lesions of the cervix. It also outlines multiple services of the NHSCSP, namely call and recall, sample takers and primary care, cytology and histology laboratories, and colposcopy. The chapter reviews the principles and theory of medical screening programmes and elaborates how the terminology is used when referring to their characteristics.
Abnormal cervical cytology
Authors: Evered Andrew
Published: September 2023

This chapter explores the epidemiology and natural history of cervical neoplasia and describes the morphological features of cellular abnormalities in the cervix. It determines the histopathological basis of cervical abnormalities and their benign lookalikes, providing a well-rounded appreciation of the benefits and limitations of cervical cytology. It also gives a brief description of the treatment methods currently available for cervical neoplasia. The chapter covers cervical glandular intraepithelial neoplasia, which illustrates the precancerous condition of the endocervical columnar epithelium and is the precursor lesion of invasive endocervical adenocarcinoma. It mentions the cytological term dyskaryosis that is used to explain the abnormal cell changes seen in cervical samples taken from women with cervical neoplasia.
Cytology of the biliary tract and pancreas
Authors: Shambayati Behdad
Published: September 2023

The chapter provides information for judging sample adequacy and gives a brief introduction to the major disease process in the biliary tract and the pancreas. Brush cytology was the most common diagnostic modality for the investigation of lesions of the oesophagus, stomach, duodenum, and large bowel until quite recently. However, as the chapter states, with increasing use of the flexible fibre optic endoscope, which allows high resolution direct visualization, endoscopically obtained tissue biopsies have slowly replaced brush cytology in the assessment of most lesions in the gastrointestinal tract. Despite this being the case, cytological techniques remain important for sampling lesions which cannot be easily biopsied, such as suspicious pancreatic masses or bile duct strictures. Confirming or excluding malignancy in a minimally invasive way avoids surgery in patients who have inoperable disease and allows for definitive treatment in potentially resectable tumours. Finally, the chapter notes, over the past few years the popularity of near-patient assessment of sample adequacy by a laboratory scientist has further increased the diagnostic value of cytology.
Remediation Ecology
Authors: Goodenough Anne E. , Hart Adam G.
Published: September 2023

This chapter focuses on remediation ecology. First, it gives an overview of pollution in relation to the development of modern society. Pollution is defined as anything harmful that is introduced into the environment by humans. The chapter lists the types and sources of pollution before turning to an exploration of the scale of pollution. It then explains the general principles of bioremediation. The chapter notes that the practice is growing fast as a result of supported advances in biotechnology and the production of genetically modified organisms. It looks at bioremediation processes using plants, which are called phytoremediation. Finally, the chapter presents an interview with applied ecologist Matthew Simpson.
Ex Situ Conservation
Authors: Goodenough Anne E. , Hart Adam G.
Published: September 2023

This chapter looks into ex situ conservation. It acknowledges that in situ conservation techniques might be needed if a successful ex situ conservation programme, which is termed reintroduction, is achieved. The chapter explores the subdivisions of ex situ conservation: intensive or general captive breeding programmes and gene banks. Additionally, it discusses the example of the Lord Howe Island Group's ex situ conservation action on the Lord Howe Island stick insect. The chapter notes the significance of collection, transport, captive breeding, reintroduction, supplementation, and reinforcement in relation to ex situ conservation. It talks about the concept of captive breeding by explaining husbandry, inbreeding, and hybridization. Finally, the chapter includes an interview with applied ecologist Dr. Tim Bray.
A brief overview of Electron Paramagnetic Resonance spectroscopy
Authors: Chechik Victor , Carter Emma , Murphy Damien
Published: September 2023

This chapter provides a background on electron paramagnetic resonance (EPR) spectroscopy, which is a magnetic resonance technique used for the study of systems containing unpaired electrons. It explains how EPR systems are paramagnetic and attracted by magnetic fields. It also reviews the applications of EPR in a wide variety of gaseous, liquid, and solid samples and confined to systems bearing unpaired electrons. The chapter outlines basic principles and the underlying physics of EPR. These are similar to those encountered in nuclear magnetic resonance (NMR). It points out how EPR and NMR techniques deal with the interaction of electromagnetic radiation with inherent magnetic moments within the sample.
Internal energy
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter assesses internal energy, which is the grand total energy of the system, the sum of all the kinetic and potential contributions to the energy of all the atoms, ions, and molecules in the system. It has a value that depends on the temperature and, in general, the pressure. An important characteristic of the internal energy is that it is a state function, a physical property that depends only on the present state of the system and is independent of the path by which that state was reached. The chapter then considers changes in the internal energy. The first law of thermodynamics states that the internal energy of an isolated system is constant. The chapter also looks at the equipartition theorem, which gives an estimate of the average energy of each mode of motion when many states are occupied.
Enthalpy
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter addresses enthalpy, which plays a role wherever processes taking place at constant pressure, a common condition in chemistry, are studied. The enthalpy of a system, a state function, is introduced in order to take energy changes arising from expansion work into account automatically. Energy transferred as heat transferred at constant pressure is equal to the change in enthalpy of the system. The chapter then considers the temperature dependence of the enthalpy; the enthalpy of a system increases when the temperature is increased. The change can be measured by monitoring the energy that must be supplied as heat to raise the temperature when the sample is open to the atmosphere (or subjected to some other constant pressure). The heat capacity at constant pressure is the slope of a graph of the enthalpy with respect to temperature.
Chemical change
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter explores thermochemistry, one of the principal applications of thermodynamics to chemistry. It begins by looking at how the strengths of bond are expressed in terms of the bond dissociation enthalpy and their mean values over a series of related compounds. The chapter then considers the standard enthalpy of combustion, which is the change in standard enthalpy per mole of combustible substance. Meanwhile, the reaction enthalpy is the change in enthalpy that accompanies a chemical reaction. The standard reaction enthalpy (the ‘standard enthalpy of reaction’) is the value of the reaction enthalpy when all the reactants and products are in their standard states. The chapter also discusses Hess's law, the standard enthalpy of formation, exothermic and endothermic compounds, and Kirchhoff's law.
Absolute entropy
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter studies the molecular interpretation of entropy and how it relates to the third law of thermodynamics. The third law of thermodynamics states that the entropies of all perfectly crystalline substances are the same at T = 0. By convention (and as justified statistically), S(0) = 0 for all perfectly ordered crystalline materials. The standard molar entropy is the molar entropy of a substance in its standard state (pure, at 1 bar) at the temperature of interest. Meanwhile, the statistical entropy is the entropy calculated from the Boltzmann formula, as the logarithm of the weight of a configuration. The chapter then looks at the residual entropy of a solid, which is the contribution to the entropy at T = 0 from positional disorder that is frozen in.
The Gibbs energy
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter looks at Gibbs energy, which is a central concept in chemical thermodynamics and electrochemistry. It begins by looking at the standard reaction entropy, which is the difference in molar entropy between the products and the reactants in their standard states. To apply the second law correctly, it is important to calculate the total entropy, the sum of the changes in the system and the surroundings that jointly compose the ‘isolated system’ referred to in the second law. Provided the temperature and pressure are constant, the direction of spontaneous change is in the direction of decreasing Gibbs energy. At constant temperature and pressure, the maximum non-expansion work available from a process is equal to the change in Gibbs energy.
Solutions
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter examines solutions. Chemistry is concerned with liquid solutions as well as gaseous mixtures, so for thermodynamic discussion of their properties it is necessary to have an expression for the chemical potential of solutes and solvents. The key to setting up an expression for the chemical potential of a solute is the work done by the French chemist François Raoult. Raoult's law states that the partial vapour pressure of a substance in a liquid mixture is proportional to its mole fraction in the mixture and its vapour pressure when pure. An ideal solution is one in which both components obey Raoult's law over the entire composition range. Meanwhile, Henry's law states that the vapour pressure of a volatile solute B is proportional to its mole fraction in a solution. An ideal–dilute solution is one in which the solute obeys Henry's law.
Response to conditions
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter addresses a very important question in chemistry, which is how to influence the yield of a reaction by increasing the equilibrium constant by changing the conditions, especially the temperature, at which the reaction takes place. Le Chatelier's principle states that when a system at equilibrium is subjected to a disturbance, the composition of the system adjusts so as to tend to minimize the effect of the disturbance. The variation of an equilibrium constant with temperature is expressed by the van 't Hoff equation. The chapter then differentiates between an endothermic reaction and an exothermic reaction. When a system at equilibrium is compressed, the composition of a gas-phase equilibrium adjusts so as to reduce the number of molecules in the gas phase. Meanwhile, the equilibrium constant of a reaction is independent of the presence of a catalyst and is independent of the pressure.
Ions in solution
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter focuses on ions in solution. Ions interact over long distances in solution, so their solutions are far from ideal except at very low concentrations. The chapter establishes a model of the structure of an ionic solution and shows how that model is used to account for activities. Moreover, an ion in solution responds to the presence of an electric field, migrates through the solution, and carries charge from one location to another. Although this material is not ‘thermodynamic’, it can be used to measure thermodynamic quantities and gives insight into the nature of ionic solutions. The chapter then looks at mean activity coefficients before considering the Debye–Hückel limiting law, which relates the mean activity of ions in a solution to the ionic strength. It also explains the Kohlrausch law and how protons migrate by the Grotthuss mechanism.
The emergence of quantum theory
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter looks at the experimental evidence towards the end of the nineteenth century that showed that classical mechanics failed when it was applied to very small particles and when the transfers of energy were very small. It discusses classical mechanics and shows how it predicts a precise trajectory for particles, with specified locations and moments at each instant. It also describes experiments which have showed that energy was transferred only in discrete amounts and showed that electromagnetic radiation behaves like a stream of particles. The chapter analyzes how electrons, which had been supposed to be particles since their discovery in 1897, can behave like waves. It reviews the translational, rotational, and vibrational modes of motion that are excited to any energy simply by controlling the forces that are applied.
Molecular orbital theory: homonuclear diatomics
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter talks about the concept in molecular orbital theory (MO theory) wherein the atomic orbital is extended to a wavefunction that spreads over all the atoms in a molecule called molecular orbital. It begins with an account of the hydrogen molecule-ion, H2
+, which sets the scene for the application of MO theory to molecules in general. It also reviews principles established for the hydrogen molecule-ion that are readily extended to other homonuclear diatomic species. The chapter considers molecular orbitals as wavefunctions which spread over all the atoms in a molecule and each one can accommodate up to two electrons. It describes the one-electron hydrogen atom which is taken as the fundamental species for discussing atomic structure and developed into a description of many-electron atoms.
Vibrational spectroscopy
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter highlights expressions for the vibrational energy levels of diatomic molecules that are first established by treating the molecules as harmonic oscillators and are then refined by deviations from harmonic motion. It examines how the vibrational spectra of gaseous samples show features that arise from the rotational transitions that accompany the excitation of vibrations. It also discusses the vibrational spectra of polyatomic molecules by imagining that they consist of a set of independent harmonic oscillators in order to interpret the vibrational spectra of large molecules. The chapter observes transitions between the vibrational states of a molecule, which gives information about the identity of the molecule and provides quantitative information about the flexibility of its bonds. It highlights how twisting, stretching, and bending molecules in different regions and in different manners can be excited by the absorption of electromagnetic radiation.
Electronic spectroscopy
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter pays special attention to the Franck–Condon principle, which asserts that electronic transitions occur within a stationary nuclear framework. It explains how the Franck–Condon principle is used to show how electronic transitions are accompanied by vibrational transitions and results in broad bands of absorption. It also covers the characteristic absorptions of some molecules that can be ascribed to the presence of certain chromophores. The chapter explores the origins of electronic transitions in molecules in order to understand the colours of objects and how chemical reactions may be initiated by absorption of radiation. It describes spectroscopic techniques that provide experimental tests of molecular orbital theory.
Biological and synthetic macromolecules
Authors: Atkins Peter , Paula Julio de , Smith David
Published: September 2023

This chapter describes macromolecules that adopt shapes governed by molecular interactions, including van der Waals interactions, hydrogen bonding, and the hydrophobic effect. It considers a range of structures, beginning with a structureless random coil and then progressing to the structurally precise proteins and nucleic acids. It also covers the mechanical and thermal properties of macromolecules. The chapter demonstrates how to describe the structural features of macromolecules in order to understand their physical, chemical, and mechanical properties. It analyzes the structure of a macromolecule that takes on different meanings at the different levels at which the arrangement of the chain or network of its building blocks are considered.
Periodicity and chemistry of the s and p blocks
Authors: Almond Matthew , Spillman Mark , Page Elizabeth
Published: September 2023

This chapter evaluates the periodicity and chemistry of the s and p blocks. The original construction of the periodic table depended to a large extent upon observation of trends in the chemistry of the elements. Subsequently, understanding of atomic theory has allowed the theoretical background to these trends and the structure of the periodic table to be understood much more fully. The trends in chemistry on moving down a group or across a period are the basis of the concept of periodicity. The chapter first looks at the physical basis for the trends in chemistry seen on moving across a period. It focuses on three fundamental properties: atomic and ionic radii, ionization enthalpies, and electron affinities (electron gain energies). The subsequent sections of the chapter then consider the different group trends.
Solids
Authors: Almond Matthew , Spillman Mark , Page Elizabeth
Published: September 2023

This chapter focuses on solids. It begins by looking at the packing of spheres to give solid structures, identifying the types of arrangements of atoms. These include hexagonal close packing (hcp), cubic close packing (ccp), and body-centred cubic structure (bcc). The chapter then studies ionic lattices, describing a few of the most common ionic structures that are based on close packing and considering the arrangements of the ions in these structures. It also discusses the radius ratio rule, which predicts the structure that an ionic solid will adopt based upon the ratio of the cation to anion size. Finally, the chapter examines lattice enthalpy and the Born–Haber cycle, as well as the theoretical methods for calculating the lattice enthalpy, including the Born–Landé equation and the Kapustinskii equation.