bluuebunny/crossref_metadata_2025 huggingface dataset:
Ammonia Synthesis – Biological
Authors: Newton William E.
Published: September 2010

Although abundant, the N
2
gas in the Earth's atmosphere cannot be metabolized directly by most organisms and, consequently, cellular nitrogen is usually obtained in a “fixed” form, such as ammonia, nitrate, or as part of an organic molecule. These sources of “fixed” nitrogen are relatively scarce and represent the most‐often limiting nutrient in agricultural systems. Because organic nitrogen is incompletely recycled in the global ecosystem and because the available ammonia and nitrate are continually metabolized to N
2
, the biological reduction of N
2
occupies a pivotal position in the biogeochemical nitrogen cycle. This process, called nitrogen fixation, is performed only by prokaryotic microorganisms and it is catalyzed by the enzyme, nitrogenase. N
2
‐fixing microorganisms may be either free‐living or associated symbiotically with plants (or animals). The most agriculturally significant are the symbiotic microorganisms that live within the plant tissue in nodules, where they “fix” N
2
and deliver it to their host. The most commonly encountered nitrogenase is a molybdenum(Mo)‐based enzyme complex, but similar vanadium‐based and iron‐based enzymes are known plus a fourth unique system. The three‐dimensional structures of the two component proteins of Mo‐nitrogenase are known. Most nitrogenases also catalyze the reduction of many other substrates (e.g., C
2
H
2
, N
3
−
, HCN) in reactions that are inhibited by CO. Substrate reduction is accomplished by a series of association–dissociation cycles in which electrons (accompanied by MgATP hydrolysis) are transferred from the Fe‐protein component to the MoFe‐protein component on which substrates are bound and reduced. Each nitrogenase is genetically distinct and its biosynthesis, maturation, and activity are regulated by many genes, e.g., 20
nif
(nitrogen‐fixation‐related) genes are required for the single Mo‐nitrogenase of
Klebsiella pneumoniae
. A fundamental understanding of the biochemical action and genetic regulation of the nitrogen‐fixation components has significant potential for improving the economy of nitrogen fixation, minimizing water pollution, and increasing global food supplies.
Metal Nitrides
Authors: Sung Lee Jae , Hyeon Taeghwan
Published: September 2010

Transition metal nitrides are characterized by high melting points, hardness, and resistance to corrosion. These physical properties are desired for catalytic materials that require resistance against attrition and sintering under reaction conditions. Since high specific area materials became available with clean surfaces, they have attracted considerable attention as catalysts for many reactions including hydrotreating (hydrodesulfurization, hydrodenitrogenation, and hydrodeoxygenation) hydrogenation, dehydrogenation, and ammonia synthesis. Metal nitrides demonstrate catalytic advantages over their parent metals in activity, selectivity, and resistance to poisoning. They have been found to be good catalysts for a number of reactions typically catalyzed by noble metals of high cost and limited supply. Structure, bonding, synthesis, and surface reactivity of transition metal carbides are discussed.
Reforming—Heterogeneous
Authors: Costa Bruno Dalla , Peralta María A. , Querini Carlos A.
Published: September 2010

In this article, the fundamental aspects of the catalytic naphtha reforming process are presented. The more important reactions that take place in a reforming reactor are discussed in detail. The discussion includes the analyses of the reaction mechanisms, the kinetics, and the thermodynamic as well as the effect that the reaction has on the product quality, as indicated by the research octane number and the Reid vapor pressure. Reforming catalyst preparation is also presented. The most important bimetallic catalysts, such as platinum–rhenium, platinum–tin., platinum–iridium, and platinum–germanium are compared. The particular features of the preparation of each of these catalysts are included in this article. The influence of catalyst composition, feed composition, operational variables (temperature, pressure, hydrogen to hydrocarbon ratio) on catalyst deactivation is addressed. Also, the effects that different poisons (metals, sulfur, basic compounds) have on catalyst activity and regenerability are briefly reviewed. Finally, the general procedure for catalyst regeneration is presented.
The Application of RecombinantDNATechnology in Medicinal Chemistry and Drug Discovery
Authors: Basu Soumitra , Oyelere Adegboyega
Published: September 2010

Discovering new drugs has never been a simple matter. From ancient times to the beginning of the nineteenth century, treatment for illness or disease was based mainly on folklore and traditional curative methods derived from plants and other natural sources. The isolation and chemical characterization of the principal components of some of these traditional medicines, mainly alkaloids and the likes, spawned the development of the modern pharmaceutical industry and the production of drugs in mass quantities. Consequently, the industry has undergone profound changes within the last millennium. As the companion chapters of this volume describe, the emphasis has changed from isolation of active constituents to creation of new, potent chemical entities. This evolution from folklore to science is responsible for the thousands of pharmaceuticals available worldwide at present.
Analog Design
Authors: Wermuth Camille G.
Published: September 2010

Analog design is usually defined as the modification of a drug molecule or of any bioactive compound in order to prepare a new molecule showing chemical and biological similarity with the original model compound. Excellent descriptions of the various possibilities of bioisosteric replacement are found in Cannon's chapter “Analog Design” published in the previous edition of this book. As a rule, it is expected that the analog exhibits some improvements over the original drug molecule, but sometimes financial motivations are predominant and justify the decision to prepare an analog in order to share market parts. Analog design is a fruitful procedure, easy to practice, and very popularly employed in pharmaceutical research from the beginning. Particularly, from the second half of the twentieth century, the production of very sophisticated molecules such as steroids, prostaglandins, anticancer drugs, and antibiotics became available and considerable advances could be made in medicinal chemistry. Analog design represents two‐third of all small molecule sales. Among the 29 new drugs launched in 2000, 24 were copies.
Hematopoietic Agents
Authors: Pelus Louis M. , Hoggatt Jonathan , Singh Pratibha , Sampath Janardhan
Published: September 2010

Adult hematopoietic stem cells self‐renew, proliferate, and differentiate forming and maintaining appropriate levels of all the cellular components of blood as well as responding to increased demand. This lifelong process termed hematopoiesis is regulated in part by hematopoietic growth factors, interleukins, and chemokines. In an incredibly short period of time, since the discovery of culture systems and animal models that detected the growth of blood progenitor cells and identified the existence of hematopoietic stem cells in the 1960s, cytokines controlling their function have been identified, cloned, and brought into clinical practice. These agents have had a major impact on patient outcomes and the ability to treat disease. Clinicians now have the tools to modulate erythrocyte, neutrophil, and platelet production enabling treatment of congenital and iatrogenic conditions and harvest of hematopoietic stem and progenitor cells for curative hematopoietic transplantation. In this chapter, hematopoietic cytokines, mimetics, and other agents approved for use in humans are described. The fields of experimental hematology and cytokine research continue to expand and new interleukins continue to be identified. As our knowledge of hematopoietic cell function increases, so will our understanding of the cellular and molecular biology of cytokine actions, and the clinical use of these agents will be refined. The potential application of several newly defined cytokines is discussed as well as the potential for the future development of cytokines that directly regulate hematopoietic stem cell function.
Vitamins
Authors: Block John H.
Published: September 2010

Biochemical processes cannot operate without vitamins. Vitamins have a variety of functions and some have dual roles. Vitamin A (retinol), in its active form, is both a regulator of cell division and a structural component of the visual pigment, rhodopsin. Vitamin D (cholecalciferol), after a two‐step hydroxylation in two different organs, is a hormonal regulator of calcium transport and cell division. Vitamin K is a coenzyme for carboxylation of glutamic acid. Vitamin E (α‐tocopherol) is a lipid‐soluble antioxidant. Thiamine (vitamin B1) is a coenzyme for decarboxylation of α‐keto acids and transketolase reactions in carbohydrate metabolism. Riboflavin (vitamin B2) is the active portion of the coenzymes FMN and FAD. Niacin/niacinamide are the active portions of the coenzymes NAD and NADP. The pyridoxine group (vitamin B6) is the coenzyme for amino acid metabolism including transaminations and decarboxylations. Pantothenic acid is a structural component of coenzyme A. Biotin is a coenzyme for four carboxylation reactions. Folic acid is a coenzyme for one‐carbon metabolism. Vitamin B12(cobalamin), with folic acid, is required for regeneration of methionine and, singly, is the coenzyme required for the rearrangement of methylmalonyl CoA. Ascorbic acid is a general free radical scavenger and required for at least eight biochemical reactions requiring oxidations. Vitamins A and D have provided the medicinal chemist with the basic structure to develop pharmacologically active molecules indicated for a variety of diseases. Some of the vitamins are toxic when taken in excess and have defined tolerable upper intake levels.
Cholinergics/Anticholinergics/Muscarinics/Nicotinics
Authors: Griffith Robert K.
Published: September 2010

This chapter quickly summarizes the cholinergic nervous system and the structures of muscarinic and nicotinic receptors. The structure–activity relationships of muscarinic agonists and antagonists are discussed with reference to attempts to develop of drugs selective for one of the five muscarinic receptors, both agonist and antagonists. The structure–activity relationships of agonists and antagonists of nicotinic receptors are presented with initial concentration on the neuronal nicotinic receptors and ending with neuromuscular blockers used in surgery.
Therapeutic and Diagnostic Agents for Parkinson's Disease
Authors: Booth Raymond G. , Neumeyer John L. , Baldessarini Ross J.
Published: September 2010

This chapter summarizes the neurobiology of Parkinson's disease and medicinal chemistry relevant to treatment of this neurodegenerative disorder with neuropsychiatric complications. The chapter also surveys basic clinical features of Parkinson's disease, its neuropathophysiology and etiology. Considered are genetic, maturational, metabolic, and environmental contributors to risk for the disease. Pharmacotherapy for Parkinson's disease includesl‐dopa to counter cerebral dopamine deficiency, direct dopaminergic agonists, and agents that prolong the actions ofl‐dopa or dopamine by preventing their metabolism by peripheral aromatic amino acid decarboxylase, catechol‐O‐methyltransferase, or monoamine oxidase. Additional drugs acting on nondopaminergic systems include muscarinic acetylcholine, adenosine, andl‐glutamate antagonists, as well as serotonin (5‐hydroxytryptamine) agonists. Agents used to diagnose Parkinson's disease and monitor its progression, include radioactive compounds used to image brainl‐dopa and dopamine neurotransporters and dopamine receptors. Finally, potential contributions are considered of medicinal chemistry to improve pharmacotherapy of Parkinson's disease.
Antihypertensives: Renin Inhibitors
Authors: Tice Colin M. , McGeehan Gerard M. , Claremon David A.
Published: September 2010

Renin has been recognized as an attractive target for antihypertensive drugs since the 1950s. Intensive efforts in the 1980s focused on peptidomimetic hydroxy transition‐state isosteres led to many potent renin inhibitors. However, none of these compounds was developed as a drug. The advent of routine X‐ray crystallography of protein–ligand complexes provided additional insights that culminated in the discovery of aliskiren, a fully nonpeptidic renin inhibitor. Aliskiren, the first direct renin inhibitor to reach the market, was approved as an antihypertensive in 2007. Preliminary clinical trials suggest that aliskiren, and potentially other direct renin inhibitors, may have utility in end organ protection and congestive heart failure, in addition to hypertension.
AtherosclerosisI:LDLCholesterol Lowering
Authors: Burnett Duane A. , Davis Harry R.
Published: September 2010

Lowering LDL cholesterol in patients has been directly linked to lowering the incidence of cardiovascular disease and represents one of the most successful avenues of medicinal chemistry. This chapter discusses current drugs on the market and in development that effectively lower this key biomarker of heart disease. Mechanistic pathways presented are HMG‐CoA reductase inhibition, cholesterol absorption inhibition (NPC1L1 inhibition), and the use of bile acid sequestrants. New therapeutic targets, such as PCSK9, antisense apoB 100 and MTP inhibition, as well as combination therapy are also presented.
HIV
Integrase
Authors: Johns Brian A.
Published: September 2010

Integrase (IN) is one of only three viral enzymes encoded by the human immunodeficiency virus (HIV). The enzymatic activity of IN catalyzes the “integration” of viral double‐stranded DNA into host chromatin. Several steps including assembly, nuclear import, and gap repair are involved in the overall integration process, but two distinct biochemical steps are catalyzed by IN. The first step called 3′ processing allows for water to cleave the terminal dinucleotide on the respective ends of the viral DNA. The second discreet step called strand transfer facilitates the nicking of the host DNA by the recessed 3′ hydroxyl groups of the processed viral DNA. It is this second step of strand transfer that has been the focus of the bulk share of drug discovery efforts to date and the only step successfully inhibited by compounds that all fall into a class called two‐metal chelators. The science around the integrase enzyme is presented from a high‐level view of integration as part of the retroviral replication cycle through a molecular view of the biochemistry of the integration process involving nucleic acid strands. This chapter discusses inhibition of the strand transfer process and presents the two‐metal pharmacophore model and inhibitor design. The body of this work is focused on numerous classes of two‐metal chelation inhibitors of HIV‐1 integrase including several clinical candidates. The chapter concludes with a short survey of potential next‐generation compounds that have appeared in the literature through the end of 2008.
Antiprotozoal/Antiparasitic Agents
Authors: Woster Patrick M.
Published: September 2010

Collectively, diseases caused by parasitic protozoa, includinghuman African trypanosomiasis(HAT), Chagas' disease and leishmaniasis, threaten more than 550 million people worldwide and cause nearly 150,000 deaths annually. The causative organisms for these diseases are unicellular trypanosomatid parasites of the generaTrypanosoma brucei,Trypanosoma cruzi, andLeishmaniasp., respectively. Drug therapies available for these diseases have not changed significantly in the past 50 years, and currently used agents are far less than satisfactory due to extreme toxicity, and because resistant parasitic strains are becoming more prevalent. These diseases are confined to impoverished or rural areas of Mexico, Central America, South America, sub‐Saharan Africa, the Middle East, Indonesia, and India. As such, drug discovery efforts against trypanosomatid diseases are limited because patients in underdeveloped areas cannot afford therapy, and because the infected population is too small to justify the required research expenditures. In addition, antiparasitic research in Third World nations is often hampered by economic issues and political turmoil, virtually assuring that the world's most impoverished people will continue to bear the major burden of parasitic disease. Clearly, there is a need for new anti‐infective agents that are potent, nontoxic and inexpensive to manufacture. In this chapter, the etiology of these diseases and their current treatment are described. The chapter also deals with medicinal chemistry aspects of efforts to identify new drug targets for parasitic diseases, and to produce novel inhibitors of trypanosomatid growth for use as antiparasitic agents.
Anti‐DNAVirus Agents
Authors: Holý Antonin , De Clercq Erik
Published: September 2010

Anti‐DNA virus agents that are inhibitory to the replication of DNA viruses have been reviewed by Tim Middleton and Rockway in Burger's Medicinal Chemistry, 6th ed., volume 5. Here we will address the various agents effective against these different viruses. For each of the (classes of) compound(s), we will, where applicable, specifically focus on (i) the antiviral compounds that are clinically available; (ii) the antiviral compounds that are under (pre)clinical development; (iii) the mechanism of action of the compounds; (iv) their structure–activity relationship (SAR); (v) resistance that may have arisen; (vi) recent clinical data obtained with the compounds while under development. Previous reviews on antiviral agents have been dealing with “looking back in 2009 at the dawning of antiviral therapy now 50 years ago: an historical perspective,” highlighting the discovery of acyclovir [9‐(2‐hydroxyethoxymethyl)guanine] as a specific antiherpetic agent, “the design of drugs for HIV and HCV,” “HIV drug development: the next 25 years,” “interferons at age 50: past, current, and future impact on biomedicine,” “the way forward in HCV treatment‐finding the right path,” “antiviral treatment of chronic hepatitis B virus infections: the past, the present, and the future,” “antiviral agents active against influenza A viruses,” “the war against influenza: discovery and development of sialidase inhibitors,” “antivirals and antiviral strategies,” and “clinical potential of the acyclic nucleoside phosphonates cidofovir, adefovir, and tenofovir in treatment of DNA virus and retrovirus infections.”
Chemical Perspective on Neurotransmission and Drug Discovery for the Central Nervous System
Authors: Mailman Richard B. , Vrana Kent E.
Published: September 2010

In this chapter, we review the evolution of approaches that have influenced the drug discovery and medicinal chemistry of agents active in the central nervous system (CNS). While Ehrlich's century‐old concept of the magic bullet governed the theory of discovery, the reality was driven for decades by what might be termed exploited serendipity. This changed markedly when, first, radioreceptor assays became widely available, and soon thereafter, when molecular biology gave the field first cloned receptors, and later the whole‐genome. Although of immense scientific use, these advances did not yield a pipeline flooded with novel drugs. They have, however, provided the tools needed for truly innovative drug discovery. Several newer concepts have now been shown to offer future directions for drug discovery. First, it is clear that drugs that target several receptors (magic shotguns) can sometimes provide CNS clinical profiles not achievable by magic bullets. Second, the use of allosteric ligands that target sites of receptors or proteins distant from the binding site of their endogenous ligands or substrates has opened new horizons for modulation, activation, or blockade of difficult targets. Finally, the definitions of agonist or antagonist have become complicated by the concept of functional selectivity, the phenomenon where a single ligand acting at the same molecular target can differentially affect the signaling pathways mediated by the receptor. These newer ideas make the importance of collaboration between biologist and chemist even more crucial, and while complicating our concepts of drug action, provide a future richness of discovery opportunity.
Stroke Therapy
Authors: Nantermet Philippe G. , Shalen Evan F. , Venkatraman Shankar , Zhu Hong , Mark Robert J.
Published: September 2010

This chapter focuses on the acute neuroprotection targets that have had sufficient medicinal chemistry activity to warrant a commentary.
Non‐amyloid Approaches To Alzheimer's Disease
Authors: Veng Lone , Savage Mary J. , Barrow James C. , Zerbinatti Celina V.
Published: September 2010

Alzheimer's disease (AD) brain is defined by extracellular amyloid plaques and intracellular Tau aggregates that are believed to cause the neurodegeneration and devastating cognitive dysfunction of AD patients. AD therapies have focused primarily on intervening at brain amyloid levels; however, since both small molecule and immunotherapy approaches to reduce amyloid have yet to show cognitive improvement in AD patients, interest in new interventions that can provide additional benefits is on the rise. This review focuses on therapeutic approaches addressing metabolic risk factors and development of targets that reduce Tau pathology.
Polymer Adsorption
Authors: Pavlukhina Svetlana , Sukhishvili Svetlana
Published: September 2010

Adsorbed polymers at interfaces are used to control interactions between surfaces in a wide range of applications such as lubrication, adhesion, food processing, and paints. Recent developments have enabled new applications using adsorbed polymers to create surfaces capable of regulating cell adhesion and proliferation. This article summarizes the current theoretical understanding of polymer adsorption and the experimental techniques used to study adsorption of neutral and charged polymers.
Cryogenic Properties
Authors: Hartwig G.
Published: September 2010

Cryogenic applications of polymers are mainly connected with superconductivity, space technology, and liquefied gases. They include superconducting motors or pulsed magnets for fusion technology, which require materials to fatigue and electrically resistive to eddy currents. Support elements for liquid‐gas containers require low thermal conductivity and good mechanical strength. Polymers are used as potting materials for superconducting magnets, electrical insulation of superconducting cables, optical data storage by selective frequency absorption, and composites for low temperature technology. Frequency selectivity is increased at cryogenic temperatures because of lowered thermal broadening. The high strength or stiffness, thermal and electrical capabilities, and the fatigue endurance limits of fiber composites are the chief reasons for their cryogenic applications. At cryogenic temperatures, interchain interaction governs most polymer properties, as is evident for elasticity and most thermal properties.

Below 200 K, dielectric and mechanical loss tangents exhibit the same temperature dependence; their ratio is a constant determined by the polarity of polymers. Most polymers are brittle at low temperatures owing to freezing of intrachain interactions. At very low temperatures, ie, <1 K, quantum‐mechanical effects predominate in phonon interactions.
Ionomers
Authors: Kim Joon‐Seop , Luqman Mohammad , Song Ju‐Myung
Published: September 2010

Since the early 1950s, the introduction of ionic groups has been recognized as a tool that can change the polymer properties. Thus, ionomers, polymers that contain a small amount of ionic groups along the polymer backbone chains, have received considerable attention from industrial as well as academic arenas. It has been found that ionomers exhibit unique properties and morphology, such as twoTgs, high melt viscosity, transport behavior, and SAXS “ionomer” peak. In this article, we set out with a introduction on ionomers, and then move on to multiplet/cluster concepts. Subsequently, the glass transition temperatures of ionomers have been discussed. The next section is devoted to a discussion of physical properties of various ionomers, that is, polyethylene‐based ionomers, polytetrafluoroethylene‐based ionomers, polystyrene‐based ionomers, block ionomers, telechelic ionomers, and star ionomers. In the following section, three different types of plasticization using polar, non‐polar, and amphiphilic plasticizers are discussed. Then, various ionic interactions as a tool for miscibility improvement are described. The last section deals with the applications of ionomers briefly.
Graft Rejection: Immunological Suppression
Authors: Afzali Behdad , Lechler Robert , Lombardi Giovanna
Published: September 2010

Transplantation of solid organs is the treatment of choice for most patients with end‐stage organ diseases. In the absence of pharmacological immunosuppression, recognition of foreign (allogeneic) histocompatibility proteins expressed on donor cells by the recipient's immune system results in rejection of the transplanted tissue(s). One‐year renal transplant survival is now routinely over 90% in most centres, largely the result of improvements in immunosuppressive drugs. In this article, we review commonly used immunosuppressive medications and discuss their pharmacological modes of action. Given that long‐term graft outcomes remain poor despite improvements in early transplant survival, we discuss, in addition, novel experimental strategies for the induction of tolerance to transplanted tissues that have translational relevance to human organ recipients.

Key Concepts:

The major limitation of solid organ transplantation is long‐term immunosuppression which either results in excessive mortality and morbidity or is insufficient to prevent chronic rejection of transplanted tissues.

An understanding of transplant rejection and pharmacological targets of immunosuppression is key to devising novel strategies of preventing rejection by inducing transplant tolerance.
Kinship Testing
Authors: Krawczak M
Published: September 2010

In kinship testing, the level of genotypic similarity between individuals at suitable genetic markers is utilised to assess their degree of familial relationship. Inference is made either by evaluating the available genotypic information under different hypotheses about kinship, represented by different pedigree structures, or through the direct quantification of kinship coefficients using a statistical approach. One complicating factor in genetic kinship testing, however, is population structure whereby the assumption of statistical independence between genotypes of unrelated individuals, or between genotypes at unlinked markers, may become violated. Similarly, physical linkage between markers can also render the simple, so‐called ‘product rule’ for composite likelihood calculation invalid. In these instances, specific statistical approaches and computer algorithms need to be used that properly adjust the relevant computations for population structure or linkage.

Key Concepts:

Kinship testing involves evaluation of the level of genotypic similarity between individuals at selected genetic markers.

The optimal basis for decision‐making in kinship testing is the likelihood ratio of different hypotheses about kinship, taking the available genetic evidence into account.

Posterior odds for given hypotheses about kinship can be calculated from prior odds and likelihood ratios, using Bayes formula.

Coancestry as arising, for example, from population structuring renders the calculation of multimarker likelihoods by simple multiplication of single‐marker likelihoods (known as the ‘product rule’) invalid.

General kinship testing is equivalent to likelihood calculations of genotypes in pedigrees, which in turn must take physical linkage between markers into account.

The degree of kinship between two individuals is quantified by their coefficient of relatedness, which equals the expected number of alleles shared identical‐by‐descent from a common ancestor.

The coefficient of relatedness is either calculated for a given type of relationship, and then used to predict genetic similarity, or estimated from observed levels of genetic similarity to infer pair‐wise relatedness.
Life Sciences in Late Antiquity and the Early Middle Ages
Authors: Frampton Michael
Published: September 2010

The life sciences in late antiquity (ad300–600) and the early Middle Ages (ad600–1000) centre around the study of three primary categories of ensouled or animate creatures, namely, plants (botany), animals (zoology) and man (anthropology). Major subdisciplines within these general areas of study include pharmacology, medicine, agriculture and veterinary science. The ancient Greek and Roman life scientists of the classical period (600bc–ad300) established much of the data and many of the fundamental concepts concerning the nature of the cosmos and its living inhabitants which scholars of the post‐classical period (ad300–1000) would inherit. The history of the late ancient and the early medieval life sciences is essentially the story of the preservation, dissemination and partial elaboration of classical Graeco‐Roman learning within several very different political, linguistic and religious contexts following the dissolution of the political and cultural synthesis that had been established under the Roman Empire (27bc–ad476).

Key Concepts:

Life science in the classical (ad300–600) and post‐classical (ad600–1000) periods centres around the study of three primary categories of ensouled or animate creatures, plants (botany), animals (zoology) and man (anthropology), and includes the subdisciplines of medicine, pharmacology, agriculture and veterinary science.

Soul (Greekpsyche; Latinanima) is the life principle of plants, animals and people, of which there are three broad species: the vegetative, sensitive and rational.

Classical anatomy, physiology, medicine, botany and zoology are tacitly accepted in the post‐classical period.

The interlocking concepts of (1) teleology, (2) the microcosm‐macrocosm analogy and (3) the great chain of being provide common conceptual ground for the ancient (classical) and the late ancient/early medieval (post‐classical) world views.

Classical life science continues to flourish in diverse religious (Jewish, Christian and Muslim) and linguistic (Latin, Greek, Persian, Syriac and Arabic) cultures following the dissolution of the political and cultural synthesis that had been established under the Roman Empire.

Greek, Latin, Syriac and Arabic languages are the primary linguistic vehicles in the diffusion of classical knowledge throughout Europe and the Middle East.

Linguistic barriers are overcome by a handful of multilingual scholars who live on the borderland of two or more dominant cultures.

Christian and Muslim post‐classical scholars use their pagan classical heritage selectively by (1) choosing organisation, conciseness and practicality over theoretical and experimental elaboration, and (2) adapting it to the sacred Scriptures of the Judaeo‐Christian (Old and New Testament) and Muslim (Koranic) cultures.
Elevational Gradients in Species Richness
Authors: McCain Christy M , Grytnes John‐Arvid
Published: September 2010

The abiotic and biotic gradients on mountains have enormous potential to improve our understanding of species distributions, species richness patterns and conservation. Here we describe how abiotic factors change with elevation, how flora and fauna respond to these changes and how elevational species richness patterns have been studied to uncover drivers of biodiversity. There are four main trends in elevational species richness: decreasing richness with increasing elevation, plateaus in richness across low elevations then decreasing with or without a mid‐elevation peak and a unimodal pattern with a mid‐elevational peak. We discuss the history of elevational richness studies and overview the various hypotheses thought to be important in richness trends, including climatic, spatial, biotic and evolutionary factors.

Key Concepts:

Elevational gradients exhibit complex variation in abiotic conditions over short distances.

Patterns of elevational species richness follow four common patterns: mid‐elevation peaks, decreasing, low‐elevation plateaus and low plateaus with mid‐elevation peaks.

Patterns of elevational species richness vary between taxonomic groups.

A combination of water availability and temperature is often found to be related to elevational species richness patterns.

No consistent support is found for the importance of area or mid‐domain effects for elevational species richness patterns.

Support for the various mechanisms underlying elevational richness patterns tends to be related to the ecology and evolutionary history of the taxonomic group of interest.

Elevational gradients are valuable in our task to disentangle the causes behind broad‐scale patterns in biodiversity, and in our quest to understand threats to biodiversity with climatic change.
Seabird Island Ecology
Authors: Mulder Christa PH , Ellis Julie C
Published: September 2010

Seabird islands house large colonies of seabirds that spend most of their time at sea but return to land to breed. Seabirds deposit large amounts of nutrients of marine origin on islands; many species also disturb soil and vegetation during the building and maintenance of nests. Physical and chemical disturbance by seabirds alters the chemical composition of soils and vegetation and modifies plant and animal communities. In many cases, the additional nutrients brought in by seabirds subsidise native animal populations, including endemic species frequently found on remote islands. Introduction of predators such as rats, cats and mustelids has resulted in population decreases or local extinction of many seabird species, and this leads to large changes in nutrient cycling and plant and animal populations. Recent efforts at eradication of introduced seabird predators have been successful, but re‐establishment of seabirds and seabird island communities will likely take additional active restoration.

Key Concepts:

Seabirds deposit nutrients of marine origin in terrestrial environments.

Seabirds impose physical disturbance on soils and vegetation in the process of building and maintaining nests.

Seabird islands often house endemic and native plants and animals that are no longer found on the mainland.

The presence of seabirds selects for plants that are tolerant of high‐disturbance and high‐nutrient conditions.

Nutrient subsidies from guano (i.e. nitrogen and phosphorus) can support increased primary and secondary productivity.

Introduced mammalian predators have eradicated seabirds and other species on many seabird islands.

The reduction of seabird populations by introduced predators alters plant and animal communities and nutrient cycling.

Eradication of seabird predators is a necessary first step towards restoration of seabird islands.

Restoration of seabird islands often requires active management of seabirds, other animals and plant populations.

Protection of seabird islands will require international cooperation on land and at sea.
Ion Chromatography
Authors: Pietrzyk Donald J. , Dicinoski Greg W.
Published: September 2010

Ion chromatography (IC), which is an important technique within high‐performance liquid chromatography (HPLC), is a chromatographic separation/detection strategy that is applied to the determination of inorganic and organic analyte anions and cations. The methodology consists of three main components: (i) an ion‐exchange column of varying capacity, where the separation occurs; (ii) a suppressor system, which reduces conductivity due to the mobile phase electrolyte; and (iii) a conductivity detector, which is used to detect the analyte ions. Anionic analytes are separated on an anion‐exchange column and analyte cations are separated on a cation‐exchange column. IC, which is routinely applied in water, environmental, health, and food analysis, is a rapid, sensitive, and accurate method for the trace determination of complex mixtures of analyte ions, particularly analyte anions, where no other method offers similar advantages and scope of application, especially when suppressed conductivity detection is employed. Modern IC is characterized by the use of electrolytic eluent generation, electrolytic eluent purification and suppression, and eluent recycling options.

Today, the term IC defines a broader group of methodologies applicable to the separation of analyte ions and now also defines the following strategies. Nonsuppressed IC of analyte anions and cations is also possible. In addition, analyte ions can be separated with an ion interaction reagent (ion pair reagent) as a mobile phase additive and a reversed stationary‐phase column rather than an ion‐exchange column; this is often called
ion interaction chromatography
(
IIC
). Ion exclusion chromatography (IEC), which is a separation of weakly dissociated acid and base analytes on an anion exchanger, is also an important methodology within the field of IC. Modern IC can also be employed for the separation of ionogenic organic molecules from simple low molecular weight carboxylic acids and amines to large organic molecules such as DNA.
Capillary Electrophoresis Mass Spectrometry: Theory and Instrumentation
Authors: Bragg William , Shamsi Shahab A.
Published: September 2010

Since capillary electrophoresis (CE) coupled to mass spectrometry (MS) was first introduced in 1987, it has continued to prove itself a complementary and/or alternative process to other separation systems coupled to MS. The impressive utility and rapid growth of CE/MS is based on three areas of development, which are covered in this article. The first is the efficient separations that are provided by the CE modes of capillary zone electrophoresis (CZE), capillary electrochromatography (CEC), and micellar electrokinetic chromatography (MEKC). Molecular micelles used in MEKC/MS and packed columns with tapered outlets for CEC/MS are two novel approaches that are contributing to rapid development. The second is the soft ionization sources, such as electrospray ionization (ESI) and atmospheric pressure photoionization (APPI), which provide efficient ways to ionize molecules in the gas phase. The third is the use of the commercially available CE instruments, which makes it possible to hyphenate all of the following modern mass analyzers. Examples of these analyzers include quadrupole mass filters, time of flight (TOF), ion traps, and the newest Fourier transform ion cyclotron resonance (FTICR) mass analyzers. The applications and developments of various modes of CE/MS show analysis of a variety of achiral and chiral compounds. In addition, the recent use of multivariate analysis with MEKC/MS and CEC/MS has shown the ruggedness of these hyphenation modes.
Pulsed Methods in Electron Spin Resonance
Authors: Bowman Michael K.
Published: September 2010

This article describes how pulsed electron spin resonance (ESR) signals and spectra are generated. A few basic pulse sequences are introduced, along with a simple vector model and the Bloch equations to explain the signals that are produced and the type of information each signal contains. The major applications of pulsed ESR are described for the measurement of ESR spectra, relaxation times, chemical reaction kinetics, molecular motion, hyperfine interactions, and the distances between radicals. The common pulse sequences used for each of these measurements are described and some of the limitations and drawbacks are discussed. The simple models for pulsed ESR are modified, as needed, to explain unexpected features encountered in some experimental measurements. Double resonance and 2D spectroscopies such as electron nuclear double resonance (ENDOR), double electron–electron resonance (DEER), and hyperfine sublevel correlation (HYSCORE) are discussed.
IFORS
: Bringing the World of
or
Together for 50 Years
Authors: del Rosario Elise , Rand Graham
Published: September 2010

In 2009, the International Federation of Operational Research Societies (IFORS), currently with a membership of 50 national societies, celebrated its 50th year since formation. This article provides an overview of the federation's history, its leadership and current composition, initiatives that have been put in place, and current activities.
Olympics
Authors: Lins Marcos Estellita , Silva Angela Moreira da
Published: September 2010

Two distinguishing issues in OR applied to Olympics are the ability to explain achievements related to available resources of a country and the capacity to shape and project domestic and global images of the host country. This paper addresses both these issues.

One particular aspect herein is the application of OR to the contents of the article itself, since the use of a tool from problem structuring methods, namely concept map helps the reader to grasp the connections between the several applications and methodologies.

This is done in three instances: to understand the rationale behind OR/MS applied to Olympics, to provide an overview of the explanatory variables for Olympic results, and to support Olympic planning.
General and Theoretical Aspects of the Metal Enolates
Authors: Domingo Luis R. , Andrés Juan
Published: September 2010

General Aspects

Structure of the Metal Enolates

Spectroscopy of the Metal Enolates

Reactivity of the Metal Enolates

Acknowledgments
Structure and Properties of
d
8
Metal–Dithiolene Complexes
Authors: Deplano Paola , Mercuri M. Laura , Serpe Angela , Pilia Luca
Published: September 2010

Introduction

Square‐Planar

d

8
Metal Dithiolenes

Molecular Conductors, Magnets and Conducting/Magnetic Hybrid Materials

Perspectives

Acknowledgments
Conjugate Addition of Hydroxylamines, Oximes and Hydroxamic Acids
Authors: Du Yunfei , Mao Deng , Zhang‐Negrerie Daisy , Zhao Kang
Published: September 2010

The conjugate addition of hydroxylamines, oximes and hydroxamic acids provides convenient route to incorporate an NO moiety into various Michael acceptors. This chapter reviews comprehensive experimental reactions on the formation of carbon–nitrogen and carbon–oxygen bonds via conjugate addition of hydroxylamines, oximes and hydroxamic acids to alkenes, alkynes or allenes attached to one or more electron‐withdrawing groups. Hydroxylamine derivatives predominantly undergo N‐centered conjugate addition, while for the ambient nucleophilic oximes and hydroxamic acids, both N‐centered and O‐centered conjugate addition are operative by control of the reaction conditions. A concerted cycloaddition mechanism has been well established for the conjugate addition ofN‐substituted hydroxylamines. The last decade has witnessed enormous growth in enantioselective conjugate addition of hydroxylamine derivatives and the O‐centered oximes.

General Introduction

Conjugate Addition of Hydroxylamine and Itsderivatives

Conjugate Addition of Oximes

Conjugate Addition of Hydroxamic Acids

Conclusions

Acknowledgments
Low Temperature Deformation Detwinning—A Reverse Mode of Twinning
Authors: Wang Yan‐Dong , Liu Wenjun , Lu Lei , Ren Yang , Nie Zhi‐Hua , Almer Jonathan , Cheng Sheng , Shen Yong‐Feng , Zuo Liang , Liaw Peter K. , Lu Ke
Published: September 2010

The origin of the plasticity in bulk nanocrystalline metals have, to date, been attributed to the grain‐boundary‐mediated process, stress‐induced grain coalescence, dislocation plasticity, and/or twinning. Here we report a different mechanism—detwinning, which operates at low temperatures during the tensile deformation of an electrodeposited Cu with a high density of nanosized growth twins. Both three‐dimensional XRD microscopy using the Laue method with a submicron‐sized polychromatic beam and high‐energy XRD technique with a monochromatic beam provide the direct experimental evidences for low temperature detwinning of nanoscale twins.
Hybridmaterialien aus Nucleinsäuren und organischen Polymeren: Synthese, Überstrukturen und Anwendungen
Authors: Kwak Minseok , Herrmann Andreas
Published: September 2010

Die Entwicklung von Hybridstrukturen aus Biomakromolekülen und organischen Polymeren, die über kovalente Bindungen miteinander verknüpft sind, ist ein intensiv bearbeitetes Gebiet. Während die Kombination von Proteinen/Peptiden mit synthetischen Makromolekülen bereits umfassend untersucht worden ist, sind bisher weit weniger Beispiele für Nucleinsäure‐Polymer‐Hybride bekannt. In diesem Aufsatz stellen wir ausgewählte Beispiele dieser interessanten Materialklasse vor, deren Vertreter lineare Blockcopolymere, Seitenkettenpolymere oder vernetzte Strukturen sein können. Der Schwerpunkt liegt auf der Herstellung derartiger Materialien sowie auf möglichen Anwendungen in der Nanowissenschaft, Diagnostik und Biomedizin.
Nucleic Acid/Organic Polymer Hybrid Materials: Synthesis, Superstructures, and Applications
Authors: Kwak Minseok , Herrmann Andreas
Published: September 2010

Extensive efforts have been devoted to the development of hybrid structures consisting of biomacromolecules and organic polymers connected through covalent bonds. While the combination of proteins and peptides with synthetic macromolecules has been explored in depth, far fewer examples of nucleic acid/polymer hybrids are known. In this Review we give selected examples of this exciting class of materials which can be arranged as linear block copolymer architectures, as side‐chain polymers, or as cross‐linked networks. Emphasis is placed on the fabrication of these materials as well as on their potential applications in nanoscience, diagnostics, and biomedicine.
Unbewehrte Betongelenke – 100 Jahre Erfahrung im Brückenbau
Authors: Schacht Gregor , Marx Steffen
Published: September 2010

Unbewehrte Betongelenke sind eine zuverlässige und dauerhafte Konstruktionsform im Brückenbau. Sie reduzieren Zwängungen und Biegemomente und verhindern somit unnötig große Beanspruchungen. Eugène Freyssinet entwickelte bereits 1909 die Idee, die Übertragung von großen Lagerkräften und moderaten Verdrehungen durch plastische Verformungen des Betons zu ermöglichen. Seit der ersten Anwendung beim Pont du Veurdre werden Betongelenke aufgrund der vielen Vorteile gegenüber Stahllagern erfolgreich in Brückenbauwerken eingesetzt. Der Beitrag zeigt die verschiedenen Anwendungsmöglichkeiten von Betongelenken im Brückenbau und erläutert einzelne ausgeführte Brücken detaillierter. Neben den wirtschaftlichen Vorteilen in der Herstellung haben Betongelenke den Vorteil, dass sie dauerhaft sind und natürliche Ressourcen schonen. Anhand eines Vergleiches der Ökobilanzen bei Ausführung eines Brückenlagers mit einem Betongelenk und einem Topflager wird der ökologische Vorteil der einfachen Lagerausbildung mit Betongelenken deutlich.
Zur Frage der Mindestbewehrung bei Aufbeton‐Verbundfugen
Authors: Randl Norbert
Published: September 2010

Zur Mindestbewehrung von Aufbeton‐Verbundfugen, wie sie im Zusammenhang mit Tragwerksverstärkungen und ‐sanierungen gebräuchlich sind, gibt es in der Literatur und einschlägigen Regelwerken stark divergierende bis widersprüchliche Aussagen. Aus Sicht der Baubeteiligten besteht der Wunsch, die Anzahl allfälliger Bewehrungselemente bzw. Verbindungsmittel möglichst gering zu halten, da diese in der Regel mit relativ hohem Aufwand nachträglich eingemörtelt werden müssen. Im vorliegenden Beitrag wird, ausgehend vom Stand der Technik und abgestimmt auf die Regelungen zur Schubfugenbemessung nach Eurocode 2, erläutert, wann auf Verbinder weitgehend verzichtet und wie andererseits bei Überschreiten des adhäsiven Verbundes in Abhängigkeit von den Verbundeigenschaften und der Schubbeanspruchung sinnvolle Bewehrungsgrade definiert werden können.