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Editor’s NoteJ Reedijk, Leiden University, Leiden, Netherlands

ã 2013 Elsevier Inc. All rights reserved.

The Reference Module in Chemistry, Molecular Sciences and Chemical Engineering has been subdivided in 10 subjects or groups of

subjects, each coordinated by a subject editor. The list of these 10 subjects, and their interrelationships, is presented below.

1. Natural Products, Chemical Biology, and Food Chemistry

2. Medicinal and Pharmaceutical Chemistry

3. Organic Methodology and Organic Synthesis

4. Supramolecular Chemistry and Heterocycles

5. Molecular Inorganic Chemistry

6. Interface and Surface Chemistry

7. Chemical Process Technology and Engineering

8. Theoretical and Computational Chemistry

9. Analytical Chemistry and Chemometrics

10. Physical Chemistry

The interrelationships between the 10 subjects and their relations with the other 3 related reference scientific fields: Biomaterials,

Materials and Earth Systems and Environmental Sciences can be presented in a schematic way:

In the present scientific field of Chemistry, Molecular Sciences and Chemical Engineering the focus will be on the molecular

parts of chemistry and engineering. Of course, borders between major areas always imply a kind of arbitrariness, and therefore

border areas can be quite large and sometimes complex. The double sided arrows in the figure above indicate such relationships,

and it is realized that these are not necessarily complete. For the division of the scientific fields, however, this grouping was chosen.

Each of the 10 topics will start with a freely accessible topic chapter, describing the 4–12 subtopics below them. Below that,

again topic chapters will be available for free, for each of the sub-subtopics. This will allow the reader to gain very easy and quick

access to the underlying full chapters.

In describing the whole of chemistry, molecular sciences and engineering, the editorial team has chosen and subdivided the area

in between the scientific fields of Biomaterials, Materials and Earth Systems and Environmental Sciences in the mentioned 10

subjects.

These 10 subjects will be briefly illustrated below, and each of them is detailed in separate topical articles, all freely accessible.

The subject Natural Products and Chemical Biology, and Food Chemistry will include the exciting Comprehensive Natural

Products Chemistry, and it was decided to have included food chemistry in this subject as natural products and food products are

likely to be searched for close to each other. It will contain a separate introduction section by an expert.

In the subject Medicinal and Pharmaceutical Chemistry newmolecules are treated, with their synthesis, and their biological and

chemical characterization, as well as structures-property relationships and applications in pharmaceutical products. It will include

the updates of the Major Reference Work Medicinal Chemistry II.

In the subject Organic Methodology and Organic Synthesis will be a logical continuation and extension of Comprehensive

Organic Synthesis 2, but at deeper levels will also include some natural product synthesis and polymer synthesis.

Reference Module in Chemistry, Molecular Sciences and Chemical Engineering http://dx.doi.org/10.1016/B978-0-12-409547-2.05403-2 1

2 Editor’s Note

In the next subject Supramolecular Chemistry and Heterocycles have been grouped. For heterocyclic chemistry the most recent

Major Reference Work Heterocyclic Chemistry III will be included; most of the supramolecular chemistry is newly added, or

extended from parts of Comprehensive Coordination Chemistry II and Comprehensive Inorganic Chemistry II.

In the broad subject of Molecular Inorganic Chemistry, Comprehensive Coordination Chemistry II, Comprehensive Organo-

metallic Chemistry III and Comprehensive Inorganic Chemistry II will be integrated. Also chapters dealing with inorganic

radiochemistry and elementary solid-state chemistry and molecular materials will be included in this subject.

The subject Interface and Surface Chemistry is not continuing on an earlier Major Reference Work, but is entirely new, and also

includes certain sections of Comprehensive Inorganic Chemistry II and electrochemistry. It is also close to the field of Materials,

Also the subject Chemical Process Technology and Engineering is a new subject as such, but several earlier Major Reference

Works covered parts of the subject, such as separation science and the Encyclopedia of Physical Science and Technology.

The subject, Theoretical and Computational Chemistry, was present as a volume in Comprehensive Inorganic Chemistry II and

as several smaller chapters in other Elsevier works. Now the field as such is made visible on it own, as one of the 10 subjects.

Elsevier has had a long tradition in covering Analytical Chemistry and Chemometrics, and several earlier encyclopedic works on

Analytical Chemistry, as well as Comprehensive Chemometric, have been included in the subject now. Comprehensive Sampling

and Sample Preparation will also be included under this heading.

The last subject has been classified as Physical Chemistry, a topic as such not visible in previous Major Reference Works.

However, it was broadly present in other areas, and therefore now the major header shows the field far better. Many entries of the

Encyclopedia of Physical Science and Technology and the Encyclopedia of Spectroscopy and Spectrometry will form part of this

subject.

Editor’s NoteSA Elias, Royal Holloway University of London, Surrey, UK

ã 2013 Elsevier Inc. All rights reserved.

Introduction 1The Multidisciplinary Approach 1Atmospheric Sciences 1Bioscience 2Energy and Natural Resources 2Geoscience 2Global Change 3Hydrology 3Oceanography 4Concluding Remarks 5References 5

Introduction

The Reference Module in Earth Systems and Environmental Sciences is a giant umbrella, covering the history of the planet, its

geology, soils, atmosphere, oceans, energy and other natural resources, and the ecosystems supported by the planet. As described by

Meeson (2010), the objective of Earth System Science is to understand how the Earth is changing and the consequences for life on

Earth with a focus on enabling prediction and mitigation of undesirable consequences. In order to achieve this objective, we must

identify how the Earth system is changing. This is accomplished in a number of different ways. We must be able to identify and

measure the primary forcings on the Earth system, both natural and anthropogenic. Second, we must develop our knowledge of

how the Earth system responds to changes in these forcings. Then we must identify the consequences of these changes for the

human race. Finally, we must be able accurately predict future changes, hopefully with sufficient advanced notice to minimize the

impacts. None of these large-scale objectives can be achieved by one scientist, or even by the scientists in one discipline. Rather, a

multidisciplinary approach must be adopted, to study the Earth as an integrated system.

The Multidisciplinary Approach

This approach to Earth System Science involves many different aspects of scientific research that must be brought together, in order

to work out the processes and interactions between the Earth’s atmosphere, hydrosphere, cryosphere, biosphere, and geosphere.

There are major sections of this module that deal with each of these disciplines. Also, any useful study of the Earth System must be

able to work at different spatial scales, from global to local, and at a range of time scales, from seconds to eons. The laws of physics

and chemistry, as well as biological principles, must be applied to describe the complex interactions between the various elements

of the system. Furthermore, historical (and pre-historic) data must be wedded with modern planetary observations, in order to gain

understanding of how systems work, how they react to various disturbances, and how they may respond to changes in the future.

Only by developing this kind of understanding can we hope to build realistic predictive models to help decisionmakers plan for the

future. The history of how the Earth System has responded to previous perturbations plays an incredibly important role in this.

Attempting to understand how the planet functions without any knowledge of its history would be like trying to unravel the plot of

a lengthy novel by only reading the last page.

Atmospheric Sciences

The Atmospheric sciences component of the module includes hundreds of individual articles, grouped under three headings:

Meteorology, Climatology, and Atmospheric Chemistry. Meteorology is the study of the weather, the day-to-day changes in the

Earth’s atmosphere on local and regional levels that bring clear or cloudy skies, sunshine, rain or snow, low temperatures and high.

The regional atmospheric circulation patterns that produce our weather are, in turn, influenced by global circulation patterns.

Phenomena such as the North Atlantic Oscillation and the El Nino Southern Oscillation are large-scale, multi-year atmospheric

circulation patterns that affect multiple continents. The cumulative effects of weather, averaged over decades, are discussed in the

Climatology section. This discipline includes the classification of climate systems, the description of climate patterns at the synoptic

level (the long-term climate at specific locations), the study of climate dynamics, and the reconstruction of the history of climate

Reference Module in Earth Systems and Environmental Sciences http://dx.doi.org/10.1016/B978-0-12-409548-9.05958-3 1

2 Editor’s Note

change (paleoclimatology). The other essential aspect of atmospheric science is the study of atmospheric chemistry. This section

includes articles on aerosols (fine particles suspended in the atmosphere), atmospheric gases (nitrogen, oxygen, carbon-dioxide,

and other trace gases), atmospheric transport, and the transfer of radiative solar energy through the atmosphere.

Bioscience

The aspects of the biological sciences covered in the module include Biogeoscience, Ecology, and Environmental Health.

Biogeoscience is the study of interactions of the biosphere with the lithosphere, hydrosphere and atmosphere. This is a rapidly

developing field, reflecting the fact that scientists are becoming increasingly aware of these interactions between the various

components of the global system. Ecology is a vast research area than began in earnest in the early 20th century and has expanded

ever since. It concerns the interactions between organisms and their environments, at various spatial scales ranging from local

Ecological Communities to global Ecosystems. Environmental pressures affect organisms at the individual level, as discussed in the

articles on Physiological Ecology and Evolutionary Ecology. The effects of environmental change are also felt at the population

level, as discussed in the Population Ecology articles. One of the chief methods of ecological analyses is through computer

modelling, as discussed in the Ecological Informatics and Ecological Models sections. The study of how ecosystems function is

far from an esoteric exercise. We must gain as great an understanding of these principles as possible, if we hope to maintain the

remaining fragments of the natural world. Regions containing undisturbed, natural habitats are increasingly being taken for various

human uses, such as agriculture and industry, towns and cities, and the roads connecting them. The fragmentation of natural

habitats is one of the most damaging of human impacts on the natural world, playing a central role in the modern extinction crisis

discussed above (Dobson et al., 2006).

The section on Environmental health mainly deals with HumanHealth, although the articles are generally framed in the context

that the health of the planet as a whole has direct effects on the health of our species. Sadly, we humans are the primary agents in

the degradation of our world’s environment. These impacts can be blatantly obvious, such as Bioterrorism, Chemical Warfare, and

exposure to man-made toxic chemicals (covered in Environmental Health Exposure and Environmental Health Toxicology and

Systems Toxicology). But they can be more subtle and harder to link directly to human agencies, such as the effects of Climate

Change, Genetically Modified Organisms, and Globalization of trade. In a worst-case scenario, Environmental Health Disasters kill

hundreds or thousands of people, such as the poisoning of more than 15000 people from the mass-release of pesticide from the

Union Carbide factory in Bhopal, India in 1984 (Jasanoff, 1994) or the exposure of many thousands of people to radiation

following the nuclear accident at Chernobyl, Ukraine in 1986 (Balonov and Bouville, 2011). Issues of Environmental Health

Justice and the Ethics of environmental issues are spawned by both large-scale disasters and day-by-day environmental degradation.

These are almost always difficult issues to tackle in the modern world, where multinational corporations operate around the world,

so that the Environmental Health Policy and Agencies of a given country have little or no authority over the overseas activities of

large corporations. Regional Environmental Health issues must take into account the Physical and Social Environment, and the

Economics of Environmental Health inevitably play a part in decision making, for better or worse. Advances in Environmental

Health Biotechnology and Environmental Health Medicine can ameliorate environmental health problems to a certain extent, but

ultimately the environmental health of any nation must be safeguarded by the leaders of industry and government, working

together for the common good.

Energy and Natural Resources

Humans are consuming fossil fuels and other natural resources at an accelerating rate that is clearly unsustainable. These are Global

Issues that are receiving increased attention from scientists, policy makers, and the world at large. This section of the module looks

at the History of Energy use, Society and Energy, and the Economics of Energy, as well as examining issues surrounding

conventional hydrocarbon-based energy resources, such as Coal, Oil and Gas and conventional Electrical Energy. These articles

set the stage for discussion of Nuclear Energy, Renewable and Alternative Energy. As we face a situation in which non-renewable

energy resources are being used up, but the demand for energy keeps climbing (Figure 1), policy makers must turn to energy

scientists for solutions. These topics are covered in Policy Issues, and Conservation and End Use, Systems of Energy and

Measurement and Models. Of course the extraction and use of energy creates environmental hazards, as discussed in the Energy

and Natural Resources Risks, Waste Management and Environmental Issues sections.

Of course energy resources are not the only reserves being consumed by humans. So this sub-module also contains articles on

Minerals, Water Resources, and Biological Resources. All the planet’s natural resources must be conserved if we are to sustain our

existence. The conservation of natural resources is discussed in Material Use and Reuse section.

Geoscience

The Geosciences are at the heart of Earth System Science, as these geological fields cover areas such as Earth History, Earth Surface

Processes, Geology, Geophysics and Geochemistry. The articles in the Earth History section deal with the history of the planet, from

its beginnings more than 4.5 billion years ago, to modern times. This includes the history of the planet itself, the changing physical

Figure 1 The global water budget, showing the breakdown of the world’s freshwater supply. Data from Shiklomanov, 1993.

Editor’s Note 3

environment, and the response of fauna and flora to those changes. The articles in the Earth Surface Processes section consider the

movement of materials, the physical and chemical fluxes across the Earth’s surface, the processes that determine these fluxes, and

the landscapes that result. The Geology articles consider the History and Philosophy of Geology, Igneous Geology, Metamorphic

Geology, Stratigraphy and Sedimentology, Mineralogy, Paleontology, Regional Geology, Structural Geology, and Geological

Applications in engineering, the military, and forensic science.

Global Change

Global change is an ever-growing topic in the modern world, so it has its own section in the module. The most widely popularized

aspect of the topic is climate change, as global average temperatures rise, polar sea ice melts, and storminess increases. These

phenomena are mostly covered in the “Atmospheric Sciences” section. The articles on the Carbon Cycle discuss the rise of

greenhouse gas concentrations in the atmosphere, which have recently reached levels not seen in the last three million years

(Figure 2).

Of course global change does not just affect human beings. It is affecting all life on the planet, as discussed in the “Bioscience”

articles. Species habitats are being altered, landscapes are being disturbed, invasive species are threatening native species, and

extinctions are increasing so rapidly that many biologists consider we are experiencing a mass-extinction event on a par with the

asteroid collision that wiped out the dinosaurs, 65 million years ago (Barnosky et al., 2011). Global change is also affecting the

planet’s Fresh Water Hydrology, in such aspects as water pollution and acid rain. Even the Earth’s crust is being altered, as discussed

in the “Geosciences” section. Increased erosion is occurring in some regions, leading to higher sedimentation rates on land and at

sea. This is only one of many global change impacts on the Ocean. Others include rising sea-surface temperatures, acidification of

ocean waters through air pollution, and rising sea levels, brought on by a combination of rising water temperatures (water expands

as it warms) and the melting of polar ice caps. Finally, the effects of global change on Society are discussed in their own lengthy

section.

Hydrology

The “Hydrology” section of the module is mainly concerned with the Freshwater Hydrology of the planet. This includes Ground

Water and Surface Water. Although the human demand for freshwater keeps growing larger every year, there is only a finite amount

of this precious substance on our planet and it constitutes just 2.5% of the planetary water supply, the rest being sea water

(Figure 1,3 ).

Of the existing freshwater, almost 69% is trapped in glacial ice. Ground water is another important component of the globe’s

freshwater resources, accounting for 30% of the freshwater supply. This leaves less than 1% of the world’s freshwater supply

available for use by all terrestrial plant and animal life (Shiklomanov, 1993). This water, like the water vapour evaporating off the

Figure 2 Per capita energy consumption since 1820, showing a breakdown of the various sources of energy used. Data from The Oil Drum web site,2012.

Figure 3 Atmospheric CO2 concentration measured by NOAA at Mauna Loa, Hawaii, 1974–2013. The concentration of CO2 rose above 400 ppm for thefirst time in recorded history on 27 May, 2013. Data from NOAA (2013).

4 Editor’s Note

oceans, forms part of the Global Water Cycle, another subsection of the Hydrology articles. Freshwater ponds, lakes and streams are

home to many species of plants and animals, as discussed in the Freshwater Biology and Aquatic Ecology articles. These organisms

are greatly affected by changes in Water Chemistry. Finally, Water Resources play a vital role in this world of increasing demand for

fresh water.

Oceanography

The study of the world’s oceans also involves a multidisciplinary group of sciences. Physical Oceanography deals with the physical

properties of ocean water, its currents and circulation patterns, and its mixing properties, aided by tides and currents. The

interactions between the ocean and the underlying sea floor are discussed in the Geological Oceanography section, including

such aspects as geothermal vents on the sea floor and the study of the sediments that accumulate on the sea floor. The history of

the world’s oceans (paleoceanography) is reconstructed from fossils and chemicals preserved in those sediments. Chemical

Oceanography deals with the chemistry of sea water, and the sources and sinks of chemicals that enter the ocean system from

Editor’s Note 5

land. Biological Oceanography considers the organisms (from viruses to whales) that live in the oceans, as well as the birds that

make their living from ocean food resources. Of course the world’s oceans are fed by rivers and streams, and the study of Estuaries,

the places where fresh water comes in contact with the ocean, form another branch of Oceanography. Finally, this section includes

articles on Marine Policy and Management, as we rely so heavily on marine resources to sustain human life in much of the world.

More than two-thirds of all humans live within 60 km of a coast, and this percentage is increasing (Halpern et al., 2008).

Concluding Remarks

The Reference Module in Earth Systems and Environmental Sciences on ScienceDirect contains thousands of articles that fall within

the major sections described above. The editorial board charged with the oversight of this electronic publication share a common

passion: the use of science to better our understanding of the world around us, and to inform the decision making process at all

levels of governance. As we have seen in this article, there are many pressing environmental issues that we must face in today’s

world. We firmly believe that ignorance of the facts surrounding these issues is not the way forward.

References

Balonov M and Bouville A (2011) Radiation exposures due to the Chernobyl accident. In: Nriagu JO (ed.) Encyclopedia of environmental health, pp. 709–720. Amsterdam: Elsevier.Barnosky AD, Matzke N, Tomiya S, et al. (2011) Has the Earth’s sixth mass extinction already arrived? Nature 471: 51–57.Dobson A, Lodge D, Alder J, et al. (2006) Habitat loss, trophic collapse, and the decline of ecosystem services. Ecology 87: 1915–1924.Halpern BS, et al. (2008) A global map of human impact on marine ecosystems. Science 319: 948–952.Jasanoff S (1994) Learning from disaster: Risk management after Bhopal (law in social context). Philadelphia: University of Pennsylvania Press.Meeson, B. (2010). Earth system science. NASA web site: http://education.gsfc.nasa.gov/esssproject/ess_definition.html visited 24 May, 2013.NOAA (2013). Trends in atmospheric carbon dioxide: Weekly average CO2 at Mauna Loa: http://www.esrl.noaa.gov/gmd/ccgg/trends/weekly.html visited 29 May, 2013.Shiklomanov IA (1993) World fresh water resources. In: Gleick PH (ed.) Water in crisis: A guide to the world’s fresh water resources, pp. 13–24. New York: Oxford University Press.The Oil Drum web site (2012). http://www.theoildrum.com/node/9023#more visited 29 May, 2013.

The Elsevier Reference Module includes continuously updated articles from 15 Elsevier Major Reference Works

› Comprehensive Biotechnology, 2nd Edition

› Comprehensive Toxicology, 2nd Edition

› Encyclopedia of Endocrine Diseases

› Encyclopedia of Microbiology, 3rd Edition

› Encyclopedia of Neuroscience

› Encyclopedia of Toxicology

› Encyclopedia of Virology, 3rd Edition

› International Encyclopedia of Public Health

› Xpharm

› Brenner’s Online Encyclopedia of Genetics, 2nd Edition

› Comprehensive Biomedical Physics

› Encyclopedia of Biological Chemistry, 2nd Edition

› Encyclopedia of Human Nutrition, 3rd Edition

› Encyclopedia of the Neurological Sciences, 2nd Edition ›

› Pathobiology of Human Disease

Immense scope. Unparalleled quality. › Nearly 5,000 articles culled from 15 Elsevier Major Reference Works and two multi-contributor volumes

› Compiled by an independent Editorial Board of 19 world-class researchers

› Over 11,000 images

“Biomedical science is an interwoven web of di� erent disciplinary threads that connect di� erent � elds and require that we have access to information in disciplines that are far outside our area of expertise.”

– Michael CaplanEditor-in-Chief for Reference Module in Biomedical Sciences, Yale University School of Medicine, New Haven, CT, USA

“The module covers the complete spectrum of biology and biomedical aspects integrated in a very well-organized fashion. As scientists we rely on correctness and something being up-to-date, so the module is important because it provides this level of knowledge.”

– Ralph BradshawSubject Editor for Reference Module in Biomedical Sciences, University of California, San Francisco, CA, USA

The Elsevier Reference Module in Biomedical SciencesOur expert researcher team has compiled the most trustworthy and current content available today, from the essentials of biomedical knowledge to the very latest scienti� c research.

Our expert researcher team has compiled the most trustworthy

For more information, visit: www.ReferenceModules.com | ScienceDirect. Get Started.

Reference Modules on

Editor’s NoteMJ Caplan, Yale University School of Medicine, New Haven, CT, USA

ã 2014 Elsevier Inc. All rights reserved.

Introduction to the Encyclopedia of Biomedical Sciences 1Physiology 2Pathology 2Cell Biology 2Genetics 3Biochemistry and Molecular Biology 3Developmental Biology 3Cancer Biology 3Microbiology, Infectious Disease and Immunobiology 3Neurobiology 4Pharmacology 4Biotechnology 4Nutrition 4Toxicology 5Epidemiology and Public Health 5

Introduction to the Encyclopedia of Biomedical Sciences

Fueled by the unbridled energy of the Enlightenment, in 1750 the French scholar Denis Diderot undertook the task of producing an

Encyclopedia whose goal was no less ambitious than the compilation of the full corpus of human knowledge in the arts and

sciences. As I contemplate what might seem to be the comparatively miniscule undertaking of assembling an Encyclopedia of that

very limited subset of human endeavor that is encapsulated within disciplines of the Biomedical Sciences, I cannot help but think

that Diderot had it easy. After all, while I am in no position to diminish the extraordinary deluge of insight and creativity that

swelled during the Enlightenment, it seems to me that by today’s standards the font of knowledge available to even the

Enlightenment’s deepest thinkers was rather shallow. Modern science was in its infancy, and the shelves in its storehouse of

verified facts were just beginning to be stocked.

Whereas Diderot and his contemporaries inhabited a world that had yet to see smart phones or widespread indoor plumbing,

we live in an age of information whose density might best be described as fractal. The closer one looks into any defined body of

current knowledge, the more one is (or should be) daunted by its undiminished enormity. In today’s compendium, every subtopic

in any organizational hierarchy seems to possess a dimensionality, richness and complexity that is comparable to that of the parent

topic from which it was spawned. This presents any modern day would-be encyclopedist with an enormous challenge, and it is

probably not too self-serving to posit that the Biomedical Sciences exemplify this challenge as well as does any contemporary

intellectual endeavor.

Within the last half century, the information density of the Biomedical Sciences has quite literally undergone the sort of

exponential growth that bacteria experience when cultivated in a nutrient rich environment. Furthermore, the density of this

information extends across biological disciplines and across scales of biological resolution. Whether one endeavors to understand a

single protein’s functional properties by defining its structure at atomic resolution or focusses instead on the physiological

implications of that protein’s function in the setting of a cell, tissue, organ or organism, one must of necessity assimilate a body

of knowledge whose magnitude might well have caused even the indomitable Diderot to question the wisdom of trying to unite

that knowledge within a single resource. Furthermore, that body of knowledge is not static. It transforms with remarkable rapidity

and in thoroughly unpredictable directions.

How then, can we be so presumptuous as to propose that the present project of assembling a useful Encyclopedia of Biomedical

Sciences is not doomed by its own enormity? The editors of the present work have been continually conscious of this question, and

been inspired by it to think about designs that ensure that this Encyclopedia’s value will transcend the challenges that are imposed

by its scope. The structure that we have developed is built, first and foremost, upon an enormous foundational body of knowledge

that has been assembled and curated by leading experts representing Biomedical Science’s many and diverse disciplines. At its

inception, this Encyclopedia of Biomedical Sciences is constituted of many thousands of individual entries. Furthermore, and

perhaps more importantly, the experts that have assembled this work’s foundation will continue to refine, expand, revisit and revise

their contributions. The work will grow and evolve along with the fields of knowledge that it explores.

As a child I believed that the massive, multivolume set of encyclopedias that proudly occupied a substantial fraction of our

bookshelves was complete and authoritative, and that it was an infallible and timeless source of everything that was knowable.

I was blissfully unaware of the fact that, with each passing moment, that encyclopedia was one moment closer to becoming

Reference Module in Biomedical Research http://dx.doi.org/10.1016/B978-0-12-801238-3.07825-9 1

2 Editor’s Note

a charming antique. To be useful, the currency of any resource devoted to the Biomedical Sciences must be monitored and

maintained to ensure that incorporates all of the latest information and sheds those concepts that have become outmoded. It is not

enough, however, to simply permit any such resource to be continually and uncritically fed from the gushing spring of new

information. Unfiltered information may be contaminated with noise that that drowns out essential messages and central themes.

All of the foundational content that has been included in the present Encyclopedia of Biomedical Sciences has been subjected to

rigorous editorial review for validity, currency and importance. Furthermore, the Editors and authors of this work will remain

engaged in the process of ensuring that it remains up to date through the addition of new information whose relevance and validity

have been vetted by recognized experts. Thus, the work promises to maintain an organic and vital connection to the fields that it

chronicles.

Finally, the boundaries that define the subdisciplines that together constitute the Biomedical Sciences grow ever less distinct.

Thus, any reference work that compartmentalizes its content into categories defined by historical convention rather than current

understanding risks rendering itself unwieldy. Furthermore, such a ‘classical’ design fails to reveal the threads that interconnect

nodes of information within a discipline and across disciplinary borders. One of the principal complications in designing the

present work has been to create an architecture that celebrates rather than conceals this web. Ideally, this architecture should allow

its users both to exercise their ingenuity and to enjoy the pleasure of serendipitous discovery as they crawl along these threads. The

philosopher of science Jacob Bronowski suggested that creativity in any discipline might be described as the act of revealing a

connection that had not been previously recognized. We hope to produce a reference work that serves as a catalyst for creativity

according to this definition. Furthermore, at the risk of revealing myself to be a curmudgeonly anachronism, I must confess that

I feel that the extraordinarily sophisticated search tools that power the internet, and thus our access to most of the information that

we can readily exploit, deny us the joy of accidentally finding things that we were not looking for. Some of the most interesting

things that I have found in libraries resided in the volume that sat next to the one that I was originally seeking. We hope to continue

to refine the interface for this Encyclopedia of Biomedical Sciences so that it reveals the intrinsic connectedness of its content and

thus allows a user to appreciate unanticipated connections that might never have been uncovered in a simple directed search. This

architecture is a work in progress, and its ongoing creation constitutes one of the most exciting aspects of this major project.

While the boundaries that separate the core disciplines within the biomedical sciences progressively blur, these core disciplines

nonetheless constitute useful intellectual frameworks around which to organize the editorial task of assembling and curating the

content of the Encyclopedia of Biomedical Sciences. Our Editorial Board is composed of experts drawn from each of these

disciplines, and they bring to this project their insights into the major tenets and questions that motivate these fields. It is

worthwhile, therefore, to introduce several of these disciplines and to provide very brief overviews of their primary foci.

Physiology

Depending upon how it is defined, physiology is perhaps the oldest and most interconnected of the disciplines within the

Biomedical Sciences (in the interest of full disclosure I should point out that I am a Physiologist and thus may be betraying just

a wee bit of chauvinism). In the broadest sense, physiology is the study of how the body maintains a constant and hospitable

internal milieu. This concept was first formulated in the nineteenth century by French physiologist Claude Bernard. American

physiologist Walter Canon subsequently coined the term ‘homeostasis’ to summarize the multitude of processes that are required

to ensure that an organism is able to maintain a composition that differs dramatically from that of its surrounding and often hostile

environment. These processes occur at the level of cells, tissues, organs and organisms. They involve the generation and expenditure

of metabolic energy, and they are controlled by networks of signals and elegant feedback loops. Many of these signals and feedback

loops are the province of the Endocrine System, which serves as a master control system that monitors, modulates and integrates

physiological function. Physiology explores the molecules, messages and mechanisms through which homeostasis is maintained

and that determine its parameters.

Pathology

Any machine as exquisitely complex as a human body must, of necessity, be subject to all manner of malfunctions. Much of what

we have learned about normal human physiology derives from efforts to understand the causes and effects of these malfunctions.

Human disease arises when extrinsic or intrinsic forces alter or interrupt the local or systemic mechanisms that maintain

homeostasis. Pathology is a discipline that endeavors to understand how and why normal function is perturbed, and what

consequences result from such perturbations.

Cell Biology

The cell is the fundamental building block of the human organism. Furthermore, each tissue and organ is constituted of collections

of highly specialized cell types whose physical and biochemical properties are exquisitely well adapted to their particular jobs.

Consequently, any sophisticated understanding of Biomedical Science must be predicated upon an appreciation of the structures

Editor’s Note 3

that constitute cells and themeans through which these structures are deployed both tomaintain the cell’s viability and to ensure its

utility to the larger organism. Cell biology explores this relationship between cellular form and function.

Genetics

Every nucleated human cell carries within it a nearly complete set of the instructions required to assemble a complete human being.

Furthermore, these instructions, which are embodied in the genome, are constantly referenced in order maintain cellular structure

and to permit cellular responses to physiological stimuli. A large subset of human diseases arise from inherited or spontaneous

alterations in the genome or in the machinery that tends it. Genetics seeks to understand how these instructions are encoded,

reproduced, interpreted and enacted. Recent technical advances and concerted efforts have produced an extraordinarily detailed

insight into the nature and dynamics of the human genome. Genetics endeavors to understand the mechanisms that govern the

structure and stability of the genetic material, and that control the expression of the genes that it encodes.

Biochemistry and Molecular Biology

Every biological process is, in essence, an orchestrated collection of chemical reactions. Biological structures, from the level of single

molecules to the level of complex systems, have evolved to ensure that these reactions take place efficiently, in the right place and at

the right time. The metabolism of nutrients, the generation of energy from that metabolism, and the exploitation of that energy to

build, maintain and regenerate all of the structures of the cell all exemplify the chemical nature of biological processes.

Biochemistry endeavors to understand the structures of biological molecules, to understand how those structures define their

chemical properties, and to establish how those chemical properties are employed and controlled. In many ways, molecular

biology can be seen as the engine that has driven the remarkable progress in the Biomedical Sciences that has occurred over the last

four decades. The insight it has provided into the nature and expression of the information contained in the genome has been

fundamental in efforts to understand the mechanisms and machinery of life. The tools it has provided have permitted the

mechanisms and machinery of life to be explored, manipulated and repaired with remarkable precision.

Developmental Biology

The union between sperm and egg sets in motion a program through which a single cell gives rise to a fully formed organism. This

developmental program employs highly orchestrated cell division, differentiation, death, movement and communication to

assemble a human being according to the instructions that are encoded in its genome. Considering its complexity, and its intrinsic

requirement for tremendous spatial and temporal precision, development is a remarkably robust process. Despite this robustness,

however, development is susceptible to intrinsic and environmental perturbations that underlie a wide range of human diseases.

Developmental biology investigates the processes which through all of the structures that constitute a human are generated and the

causes and consequences of errors in these processes.

Cancer Biology

Normally, cell growth and replication are tightly controlled, so that these processes occur only when and where they are needed.

Cancer is caused by a breakdown in this control, resulting in dysregulation of cellular proliferation and loss of differentiated

cellular identity to create neoplastic growth. Furthermore cancerous transformation can create cells that lose their attachment to

their normal tissue architecture and can travel through the body to metastasize, which is to say they invade and take up residence in

other tissues. Neoplasms develop through a wide variety of mechanisms, take many forms and can exert an enormous number of

profound effects on their local environments and on the physiological functioning of their host organism. Cancer biology

endeavors to understand the mechanisms through which cancer develops, the varieties of its forms, and its vulnerabilities that

render it susceptible to therapy.

Microbiology, Infectious Disease and Immunobiology

We tend to think of microorganisms as enemies. Certainly, we are subject to constant assault by a rogues’ gallery of microorganisms

that wish to do us harm. Bacteria, viruses, protozoans and parasites endeavor to exploit our nutrient rich internal environment and

to subvert our metabolism to their own nefarious ends. It is becoming ever clearer, however, that this view of microorganisms is

overly simplistic and negative. We co-exist with massive populations of commensal organisms that colonize our every nook and

cranny and that appear to participate in defining who we are and how we interact with our environment. Microbiology is a

discipline that focusses on understanding the nature of those microorganisms that cause disease and those that help to keep us

4 Editor’s Note

healthy. Our bodies employ numerous defenses in our efforts to prevent microorganisms from producing infectious diseases. The

persistent threat of infectious diseases, even in our present era of hygiene and antibiotics, provides ample evidence that microor-

ganisms have developed and continue to develop remarkably clever tools with which to subvert our best defenses. The immune

system constitutes our most sophisticated defense against infection. The immune system employs sophisticated surveillance

methods to recognize elements in our bodies that do not belong to us, and deploys manifold defenses to isolate or destroy

those elements. Not surprisingly, deficits in immune function can render us susceptible to the malevolent intentions of infectious

microorganisms. Conversely, however, an overly exuberant immune system can produce disease by attacking and destroying our

own healthy tissue. Immunobiology investigates the mechanisms through which themany cell types that contribute to the immune

system collaborate with one another to mount and regulate a response to foreign invaders.

Neurobiology

Since the time of Rene Descartes in themid seventeenth century scholars have debated how the physical entity of the brain is able to

endow us with our conscious and unconscious minds. The nervous systems endows us with our capacity to interact in sophisticated

ways with our environments, with each other and with ourselves. Our every thought, action, emotion and sensation derives from

signals that ricochet among the almost unfathomably complex network of interconnected neurons in our brains. Furthermore, the

nervous system monitors and regulates almost every aspect of our physiological functioning. Not surprisingly, therefore, neuro-

biology is a vast topic. It ranges in scope from the cell biology and biochemistry of individual neurons to the behaviors that emerge

from massive neuronal ensembles. It employs tools in its investigations that range from the analysis of single molecules to studies

that explore the neuronal activity that underlies human thought and behavior. As might be expected of such a complex entity, the

nervous system is subject to myriad varieties of pathologies that are important both for their impact on the lives of those that

endure them and for what they teach us about how the nervous system functions.

Pharmacology

Most people’s primary interaction with the fruits of the Biomedical Sciences occurs when they visit a pharmacy to fill a physician’s

prescription for a drug to treat some ailment. Some of those drugs derive from natural substances, while some are entirely synthetic.

The medical utility of some of those drug substances were recognized several centuries ago, while some are the products of the

most recent efforts to fight disease. Pharmacology is the science that focuses on discovering new drug substances, understanding

how they work and defining their interactions with the body. In its modern incarnation, pharmacology seeks to identify drug

targets—that is, activities or processes that are relevant to a disease state and that are accessible to selective biochemical

manipulation. This requirement for selectivity is extremely important, since the goal in developing a new drug substance is to

find an agent that affects only its designated target without off target actions and with a minimum of side effects. Thus,

pharmacology integrates an enormous body of knowledge about normal physiology and pathobiology in order to develop

novel approaches to treat disease that are both safe and effective.

Biotechnology

When most people think of the products of engineering, they probably visualize highways, bridges and dams or microchips and

high definition video screens. There is another field of engineering, however, whose efforts are devoted to applying technology to

provide new tools with which to treat disease and ease discomfort. As its name implies, biotechnology seeks to engineer solutions

to biomedical problems. Some of these solutions are often seen and widely known, such as artificial limbs and hearing aids,

whereas others are much less visible, such as nano-encapsulated drug delivery systems and implantable electrodes that treat

neurological diseases. In each of these cases, the goal is to find novel ways to interface the tools of technology with human biology

in order to address a substantial biomedical problem.

Nutrition

Our metabolism requires fuel, and that fuel is provided by our diet. The science of nutrition explores the nature of our metabolic

needs and themeans through which dietary substances satisfy them. While for millennia the human diet was viewed as a beneficent

source of sustenance, the past few decades have revealed that the diet can also be significant source of pathology. Excessive or

unbalanced nutrient consumption is the primary cause of obesity and its associated pathologies, whose prevalence throughout the

world has reached epidemic proportions. Understanding the factors that lead to obesity and developing strategies to reverse them is

one of the great challenges of modern nutrition science and one that will impact the Biomedical Sciences for decades to come.

Editor’s Note 5

Toxicology

We live in a world that is rife with poisons. Nature has developed all manner of toxic substances that have the capacity to do us

harm. Our own scientific progress has added substantially to this arsenal of compounds that have the capacity to interfere with vital

aspects of our fragile biochemistry. Toxicology endeavors to understand these compounds, how we come into contact with them,

how they perturb our normal function and how we can prevent or treat exposure to them. Understanding the mechanisms through

which individual toxins damage us also provides new insights into our normal physiology.

Epidemiology and Public Health

Disease effects individuals and populations. While other components of the Biomedical Sciences teach us about the mechanisms

through which disease perverts an organism’s normal function, Epidemiology and Public Health teaches us how disease develops

in, spreads through and impacts a community. Clearly in the context of infectious conditions it is critically important to understand

how a community’s living conditions and practices facilitate or impair the spread of disease. This statement is just as true, however,

in the context of all manner of human pathologies ranging from malnutrition to obesity and from birth defects to cancer. Our

societies are the sources of both major weapons in the war on disease and major causes of its propagation. Understanding the

interface between the Biomedical Sciences and human communities is at the forefront in the efforts of Biomedical Scientists to

improve the health of the world.

Provide the up-to-date information your researcher’s are looking for from 8 of our comprehensive Reference Works in one resource:• EncyclopediaofAgricultureandFoodSystems

• EncyclopediaofMeatSciences,2ndEditon

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Reference Module in Food ScienceStimulateresearchandinnovationatyourinstitutionbyequippinguserswiththelatestdevelopmentsintherapidlyevolvingfieldofFoodScience.

“FoodScienceresearchersnowadaysarelookingforthefollowingfeaturesinthereferencematerialtheysource—contentfromanauthoritativeandreliablesource,currentandtopicalmaterialincludingreal-lifeexamples,andaccessibility.TheElsevierFoodScienceReferenceModuleaddressesallthesekeydemandsfromthemodernfoodscientist.First,theModuleispublishedbytheworldsleadingtechnicalcontentpublisherwithaproventrackrecordinproducingauthoritativeandreliablecontent.Second,materialintheModulewillbecurrency-checked,up-to-date,andtopical;andallcontentwillbeoverseenbyeditorswhoareleadingexpertsinthefoodsciencefield.Finally,materialintheModulewillbeon-lineanddownloadable,andtherebyeasilyaccessiblebyresearchersfromanywhereintheworld.TheElsevierFoodScienceReferenceModulerepresentsthenextgenerationinpublishing,sourcingandaccessingreferencematerialinfoodscience.”

Geoffrey SmithersEditor-in-Chief for Reference Module in Food Science Melbourne,Victoria,Australia

“Sometimesscientiststendtobeveryspecializedinaparticularareaofthedisciplineandlosetheoverallcontest.ThismodulewillhelpfoodscientistsalwayshavetheentireperspectiveoftheFOODSCIENCEworld.”

Valentina TrinettaSubject Editor for Reference Module in Food Science Ecolab,Eagan,USA

Interested in Reference Modules on ScienceDirect?Librarians-ContactyourElseviersalesrepresentativefordetailsandflexiblepricingoptions.Researchers - Recommend to your library.

For more information, visit: www.ReferenceModules.com

Get Started.

A Note from Elsevier’s Acquisition Editor, Rachel Gerlis, on the new Reference Module in Food Science

With rapid advances in areas of food science such as technology, chemistry, safety and consumer behaviour, it is vital that we as publishers are able to keep up with the demand for the latest research on these topics.

The Reference Module in Food Science is an exciting new initiative from Elsevier that will allow food science students and researchers to discover comprehensive, time-stamped content quicker and more easily than ever before.

Working with our fantastic Editor-in-Chief, Geoff Smithers (former Director of International Business at Food Science Australia and now an independent Food Industry Consultant with close links to the Institute of Food Technologists), I’ve recruited 15 Subject Editors who are leading experts in their fields and who, between them, are responsible for reference content across the whole breadth of the food science discipline.

In the run up to launch in December 2015 these editors are reviewing thousands of encyclopedic and comprehensive reference articles for currency, updating them where necessary, and commissioning new content to ensure the continued growth of the module. They’re also creating an intuitive, interdisciplinary subject hierarchy to organise all the articles into a coherent, user-friendly framework. These are all momentous tasks but the editors are doing a superb job and we’re on track for a really successful launch.

The benefits of a Reference Module in Food Science are huge. It will provide researchers with access to thousands of cutting-edge articles in their area of expertise, up-to-date introductions to any areas they need to be brought up to speed on, and an accurate overview of the whole discipline. The Reference Module will also allow them to easily find authoritative and citable research on a specific subject, rather than having to wade through less reliable information available elsewhere on the internet.

Authors benefit by having their research made available online as soon as it’s been approved by the editors so, unlike a traditional book process, they don’t have to wait for the last author to finish writing before their article is published. As articles can be updated as and when necessary, each author also has the opportunity for their work to remain perpetually relevant in the field.

As an Acquisitions Editor, I’m always on the look-out for new opportunities to commission Major Reference Works in Food Science in order to provide the academic community with the information they need, when they need it. The Reference Module in Food Science is exciting because its interdisciplinary nature will allow me to spot gaps in our existing content and quickly and easily fill them, thus staying ahead of the latest trends in the field. Having such a comprehensive network of editors and authors connected to the project means that I can fully engage with the subject community, and fulfil their research needs more accurately and efficiently than ever before.

The Editor-in-Chief’s Note will be available when the Reference Module is live on ScienceDirect in December 2015

Provide the up-to-date information your researcher’s are looking for from 13 of our comprehensive Reference Works in one resource:• ComprehensiveBiomaterials

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• ComprehensiveStructuralIntegrity

• EncyclopediaofCondensedMatterPhysics

• EncyclopediaofMaterials:ScienceandTechnology

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Reference Module in Materials Science and Materials EngineeringStimulateresearchandinnovationatyourinstitutionbyequippinguserswiththelatestdevelopmentsintherapidlyevolvingfieldofMaterialsScienceandMaterialsEngineering.

“Itiscertainlyarevolutionarywayofthinkinginthatthereisnodeadline.Theresearcherswhoarecontributingwillhavetheopportunitytoupdatetheirarticlesonnewdevelopmentsintheirownfieldofresearch.AllofwhichwillbeincludedintheonlinedigitalsourceoftheReferenceModule.”

Saleem Hashmi Editor-in-Chief for Reference Module in Materials Science and Materials Engineering Dublin,Ireland

“Thediscoveryanddevelopmentofmaterialsarehallmarksofthegrowthofcivilizations.Scientists,engineersandresearcherssearchforappropriatematerialsforthesustainabledevelopmentofsociety.TheonlineReferenceModuleinitiativerepresentsaseminalstageintheevolutionofscientificpracticeinmaterialsscienceandmaterialsengineering.Itwillcovertheentirespectrumofthesediscoursesthroughacontinuouslyupdating,peer-reviewedknowledgebasethatwillseektoaddressthevariedrequirementsofacademics,studentsandpractitioners.”

Shahjahan Mridha, Ph.DSubject Editor for Reference Module in Materials Science and Materials Engineering Glasgow,Scotland

Interested in Reference Modules on ScienceDirect?Librarians-ContactyourElseviersalesrepresentativefordetailsandflexiblepricingoptions.Researchers - Recommend to your library.

For more information, visit: www.ReferenceModules.com

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A Note from Elsevier’s Acquisition Editor, Ruth Ireland, on the Reference Module in Materials Science & Materials Engineering

Research in Materials Science and Materials Engineering moves very quickly, and it is also a truly interdisciplinary field with relevance across a wide range of academic studies and professional industries. As such, there is a high demand from researchers at all levels for up-to-date and high-quality reference material.For publishers, it can be a huge challenge to meet that demand when the discipline is so fast-moving and when reliable, peer-reviewed reference publications can take years in the making.

The Reference Module in Materials Science and Materials Engineering is an innovative new solution to that challenge. Researchers from undergraduates to industry experts will be able to find the information they need and at the same time know that it is both current and of the highest standard.

As Acquisitions Editor on the project, it’s really exciting for me to work with an extremely knowledgeable and energetic Editorial Board of 14 Subject Editors, led by indomitable Editor-in-Chief Saleem Hashmi (School of Mechanical & Manufacturing Engineering, Dublin City University). The Editors’ powerful collective expertise and experience as researchers, teachers and industry professionals is making it possible for us to build a very dynamic and comprehensive resource. It’s also wonderful to already have contributions from expert authors from all over the world.

As we gear up for launch of the Module in December 2015, the Editors are hard at work reviewing articles and building the subject hierarchy that will enable users of the Module to search thousands of articles and quickly get to the information they want. Users will be able to see when each article was last checked for currency as well as its update history. This will give researchers the confidence in the material that they require, and teachers can point their students to a quick source of reliable, citable, up-to-date information from entry-level to expert detail. A key point is that we are developing this Module so that it will be of maximum use to researchers both within and outside of materials science. Linking tools within ScienceDirect will enable researchers to find authors who they can perhaps collaborate with on interdisciplinary projects.

Article authors benefit by no longer having to wait until the end of a long multi-article book production cycle: their work will lose none of its currency as it will publish online in the Module just as soon as it has been reviewed by the appropriate Editor and is production-ready. Authors later have the opportunity to review and update their own work as appropriate, so that their articles always remain relevant and utilized in the long term.

I’m confident that working on the Reference Module in Materials Science and Materials Engineering will help me to engage ever better with authors and researchers across the many subject areas it covers. I am always keen to discuss trends in materials science and to talk to prospective editors about developing new Encyclopedias and Comprehensive Major Reference Works.

The Editor-in-Chief’s Note will be available when the Reference Module is live on ScienceDirect in December 2015