bluuebunny/crossref_metadata_2025 huggingface dataset:
Plant Transformation Technology: Particle Bombardment
Authors: Twyman Richard M. , Christou Paul
Published: July 2004

Stable gene transfer to plants can be achieved by two general strategies—Agrobacterium‐mediated transformation and the direct introduction of DNA into the plant cell.Agrobacterium‐mediated transformation is dependent on complex biological interactions between the bacterium and host plant, while direct DNA transfer is based on chemical or physical principles. Techniques included in this category, however, require particular cell types as transformation targets, and it is not always possible to regenerate plants from such cells. Only particle bombardment, the introduction of DNA into plants using high‐velocity microprojectiles, has the potential to transform any cell type from any plant, providing a truly universal transformation strategy. In this chapter, we discuss the principles of particle bombardment and variables that must be optimised for efficient transient and stable transformation. We also discuss the fate of exogenous DNA once it has entered the plant cell, and how this influences transgene expression. A literature survey is presented, listing all the plant species that have been transformed using this method, up to the end of the year 2001.
Control and Silencing of Transgene Expression
Authors: Müller Andreas E. , Wassenegger Michael
Published: July 2004

The expression of a gene is a fundamental biological process with both immediate effects on an individual organism as well as long‐term consequences for the evolution of the living world. As such, gene expression is regulated by elaborate control mechanisms that act or interact to ensure a fine context‐specific tuning. Transgenes are subject to the same range of gene regulatory mechanisms that control endogenes. In addition, transgenes, like other newly acquired foreign or ‘invasive’ DNA elements in the genome, appear particularly susceptible to control mechanisms that detect and act upon ‘abnormalities’ encoded by the transgene sequence or structure, the transgene's positional and compositional relation to its genomic environment, the transgene's expression pattern, and the intrinsic and extrinsic characteristics of transgenic RNA intermediates and gene products. A thorough understanding of the pathway of gene expression, from transcriptional regulation by genetic and epigenetic mechanisms, through to RNA and protein degradation, and the targets this pathway provides for gene regulatory processes to intervene, is essential for the successful application of transgenic tools in today's plant biotechnology.
Engineering Pathogen Resistance in Crop Plants
Authors: Campbell Matthew A. , Fitzgerald Heather A. , Ronald Pamela C.
Published: July 2004

As the world population continues to increase, food supplies must also grow to meet nutritional requirements. One means of ensuring the stability and plentitude of the food supply is to mitigate crop loss caused by plant pathogens. Strategies for combating disease include traditional technologies such as plant breeding and chemical applications; current technologies such as generating transgenic plants that express components of known defence signalling pathways and the adaptation of newer technologies such as RNA silencing of pathogen and plant transcripts. Breeding has been used to pyramid resistance (R) genes into many different plants including rice. Chemical strategies include application of salicylic acid (SA) analogues to stimulate systemic acquired resistance (SAR) responses. Genetic screens in Arabidopsis have identified genes controlling SAR and these genes have been manipulated and used to engineer crop plants. The diseases caused by plant viruses are being thwarted through the initiation of endogenous RNA silencing mechanisms. Many of these strategies show great promise, some limitations and exciting opportunities to develop many new tools for combating plant pests.
Engineering Resistance to Insect Pests
Authors: Ferry N. , Edwards M.G. , Mulligan E.A. , Emami K. , Petrova A.S. , Frantescu M. , Davison G.M. , Gatehouse A.M.R.
Published: July 2004

With a projected increase in world population to 10 billion over the next four decades, an immediate priority for agriculture is to achieve maximum production of food and other products in a manner which is environmentally sustainable and cost effective. Despite the synthesis of improved pesticides, and integrated pest management strategies, yield losses due to insects have actually increased slightly for most crops over the last two decades.

The concept of utilising a transgenic approach to host plant resistance was realised in the mid 1990s with the commercial introduction of genetically modified crops expressing genes encoding the entomocidal d‐endotoxin fromBacillus thuringiensis(Bt). More recently this strategy has been extended to include the pyramiding (stacking) of genes encoding different Bt toxins for greater levels of pest control. Although not as yet a commercial reality, other strategies based on the use of plant derived genes (enzyme inhibitors, lectins) and those from animal sources, including insects (biotin‐binding proteins, neurohormones, enzyme inhibitors), are being developed. The use of fusion proteins to increase the spectrum and durability of resistance is also actively being pursued. However, if transgenic insect‐resistant crops are to play a useful role in crop protection, it is apparent that they must be compatible with the other components of integrated pest management (IPM).

The current chapter addresses the role of insect‐resistant transgenic crops in agriculture and discusses both their current status and future developments. Given the importance of natural enemies in controlling pest populations, the potential impact of such crops on predators and parasitoids is also addressed.
Engineering Resistance to Herbicides
Authors: CaJacob Claire A. , Feng Paul C.C. , Heck Gregory R. , Alibhai Murtaza F. , Sammons R. Douglas , Padgette Stephen R.
Published: July 2004

Crop resistance can be generated through a selection process or the introduction of a gene via transformation. We will refer to the latter as engineered herbicide resistance. The literature contains numerous studies on engineered plant resistance to various herbicide classes. There is a large distinction between demonstrating a resistance phenotype in plants versus developing a commercial resistant crop that requires consistent performance under varying environmental conditions. Creating an herbicide resistant crop must successfully navigate a maze of key technical issues while satisfying the practical product goals of agronomic equivalence, weed management, economic feasibility, governmental regulatory compliance and public acceptance. Most of our experience has been derived from developing crop resistance to glyphosate. In this review, we will utilise these experiences to describe the essential studies required for the development of a commercial herbicide‐resistant crop with emphasis on the development of glyphosate resistance.
Molecular Bases of Plant Adaptation to Abiotic Stress and Approaches to Enhance Tolerance to Hostile Environments
Authors: Coraggio Immacolata , Tuberosa Roberto
Published: July 2004

Abiotic stress has become the greatest threat to global food production and security, particularly in developing countries. Progress in increasing yield and its stability under adverse conditions through a direct selection has been hampered by the low heritability of yield, especially under drought. A better knowledge of the molecular and genetic basis of the mechanisms promoting tolerance to abiotic stress will enhance our capacity to more appropriately manipulate the genes limiting crop yield under hostile environments. This review describes and critically analyses the major advances in our understanding of the complex mechanisms underlying the adaptive response of the plant to abiotic stress, starting with the perception of the stress at the cellular level, its transduction through a cascade of signalling molecules and ending with the induction of genes whose products mitigate the harmful effects of the stress. Molecular markers and the ‘omics’ platforms (e.g., transcriptomics, proteomics, metabolomics etc.) offer unprecedented opportunities to identify and clone the genes governing plant adaptation to environmental stress and limiting yield under such conditions. The dissection of the genetic basis of quantitative traits into their single components, the so‐called QTLs (quantitative trait loci), allows us to deploy marker‐assisted selection (MAS) for enhancing crop performance under adverse conditions. Additional opportunities are also offered by genetic engineering, particularly through the expression of transcription factors regulating a suite of genes whose product is crucial to mitigate the effects of stress. Although the applicative results so far achieved with non‐conventional approaches have been limited, their integration with conventional breeding methodologies and other interdisciplinary approaches will greatly enhance our capacity to more effectively tailor crop genome to withstand harsh environmental conditions and to improve their sustainability under marginal conditions.
Carbohydrate Metabolism
Authors: Fernie Alisdair R. , Willmitzer Lothar
Published: July 2004

The yield from crop plants has been subject to improvement through conventional breeding and modifications in agricultural practice for many decades. More recently, the use of molecular genetic approaches has allowed more directed approaches towards crop improvement. Specific examples of both successful strategies and of fundamental knowledge gleaned from unsuccessful strategies are presented including manipulations of starch, sucrose and novel sugar content. The utility of metabolic control analysis in the identification of control points in metabolic pathway and its use in the prediction of changes in metabolite accumulation following enzyme modulation is discussed. Further examples of biotechnological manipulation focus on qualitative rather than quantitative aspects of carbohydrate metabolism detailing the introduction of novel pathways for synthesis, or functionalities, of polymers. Particular focus is given to fructan biosynthesis in non‐fructan accumulating species and the broad structural diversity of starch following genetic manipulation of the enzymes involved in its synthesis and degradation. Finally, the chapter concludes with an appraisal of the challenges that remain before the rational manipulation of carbohydrate becomes routine.
Genetics and Genomics of Nodulation and Symbiotic Nitrogen Fixation
Authors: Gresshoff Peter M.
Published: July 2004

‘Nitrogen’ is critical for plant productivity because of its involvement in proteins, nucleic acids and secondary metabolism. Plants are the major conduit of nitrogen assimilation into the biosphere and achieve this feat through either assimilation of mineral nitrate or biological nitrogen fixation in symbiotic structures called root nodules. The recent discovery of key genes controlling nodule initiation, nodule proliferation and plant defence now provides the opportunity to improve legumes, thereby decreasing the demands on fossil‐fuel based nitrogen fertiliser. The understanding of symbiotic nitrogen fixation led to the recognition that many of the developmental pathways are either shared or pirated from other pre‐existing regulatory mechanisms. Increasingly sustainable agricultural practices based on reduced inputs and ‘triple bottom‐line’ accounting may result. In the near future we may even hope to see the expansion of the nitrogen fixing symbiosis by either transgenic manipulation or ‘smart breeding’ to new crop species.
Male Sterility and Hybrid Production Systems
Authors: Oliver Melvin J.
Published: July 2004

The ability to exploit the long known phenomenon of hybrid vigor or heterosis, the superior performance of the F1 hybrid compared to either parent line, has greatly impacted the goal of production agriculture to meet world food demands. Hybrid production systems rely on an efficient and effective mechanism for inducing male sterility in one of the parental lines in order to ensure purity of the resultant hybrid seed. Natural male sterility systems are available but are limited in their availability for all crops and their effectiveness in those for which they have been developed. This chapter discusses the means by which modern techniques of genetic engineering have broadened our ability to develop male sterile lines and improve hybrid production strategies. The chapter discusses the development of dominant male sterility systems using genetic ablation and developmental disruption strategies, conditional male sterility strategies and the genetic engineering of maintainer lines. The generation of novel and improved systems for hybrid production in the ongoing search for crop improvement has been, and continues to be, one of the major targets for transgenic manipulations within the agricultural biotechnological community.
Plant Architecture
Authors: Jackson S.D.
Published: July 2004

The manipulation and control of plant height and shape is an integral part of modern intensive agricultural and horticultural production systems and brings several benefits to the farmer/grower. The most commonly used method to control plant height is through application of growth retardants. These are effective in all species and were developed to primarily affect stem elongation without having adverse effects on other aspects of plant growth and development. In recent years progress in plant biotechnology has provided an alternative approach to controlling plant architecture through the use of genetic modification. Whilst the technology is still being developed to address issues of public concern (‘genetic pollution’ and the use of antibiotic marker genes), it is clearly a very rapid and powerful means by which specific traits can be targeted in a very defined manner. Given the appropriate controls, genetic modification has the potential to be greatly beneficial to the environment by reducing the need to spray vast quantities of chemicals, including growth regulators, onto glass and field grown crops. This chapter will focus on the control of plant architecture in commercial crops through genetic manipulation.
Forestry
Authors: Cooke Janice E.K. , Morse Alison M. , Davis John M.
Published: July 2004

Genetic improvement plays a pivotal role in intensive management strategies for forest trees. Conventional breeding in forest trees is greatly constrained by long generation times. This is particularly true for temperate coniferous species, which rank among the most commercially important forest trees. In Aadditionally, many traits of interest exhibit poor correlation between the juvenile and mature phases of growth that are innate to trees. Consequently, these traits cannot be reliably evaluated at the morphological level until the tree has entered into mature growth, which may take several years. Given these constraints to conventional breeding, the use of biotechnology to reduce the time to create and select genetically improved trees could have a significant impact on forest tree improvement and the forest industry. In this chapter, we focus on how biotechnology has been and can be incorporated into forestry.
An Introduction to Industrial and Pharmaceutical Protein Production in Plants
Authors: Fischer Rainer , Emans Neil
Published: July 2004

This chapter provides an overview of the subject of production systems for industrial and pharmaceutical proteins.
Plants as a Source for Subunit Vaccines
Authors: Mor Tsafrir S. , Mason Hugh S.
Published: July 2004

A major challenge of biotechnology is to reduce clinical innovations to economically viable practice. While still in experimental stages of development, edible vaccines stand as an excellent example of this maxim: merging innovations in medical science and plant biology, to create efficacious and affordable pharmaceuticals. In this chapter, we present an updated report on advances in this field and in particular on the recent clinical trials. We will then outline areas of research that deserve further attention.
Perennial Plants as a Production System for Pharmaceuticals
Authors: D'Aoust Marc-André , Busse Ursula , Martel Michèle , Lerouge Patrice , Levesque Damien , Vézina Louis-Philippe
Published: July 2004

For molecular farming applications, the capacity to transform perennial plants for recombinant protein production gives access to stable and almost perpetual production of pharmaceuticals from a single population of plants. Being able to produce a bioactive protein with a uniform and well characterised population not only reduces production costs but more importantly, it ensures even and predictable production rate of a uniform product from a genetically stable population. Despite their promising potential, two main hurdles hindered the early development of perennial plant‐based expression systems: the lack of adapted expression cassettes and the difficulty to genetically transform and regenerate the best‐suited perennials. This chapter describes recent scientific breakthrough in alfalfa transformation and protein expression and purification that opened the way to the development of an efficient recombinant protein production platform using alfalfa as bioreactor.
Crop Plants for Molecular Farming
Authors: Stoger Eva , Marcel Sylvain , Twyman Richard M.
Published: July 2004

The large‐scale production of recombinant proteins in plants is known as molecular farming. From a commercial perspective, the major benefit of molecular farming is the anticipated cost savings since there are no requirements for expensive equipment or skilled labour. Transgenic plants can be maintained, harvested and processed using normal agricultural practices and existing infrastructure. Other advantages include the ease of scale up, the absence of human/animal pathogens and undesirable DNA sequences (oncogenes, endogenous retroviruses etc.) and the structural and functional similarity between plant‐derived recombinant proteins and their native counterparts. Plants have been used to produce a wide range of products, including therapeutic human proteins, recombinant antibodies, subunit vaccines, nutraceuticals, animal feed additives, biopolymers, molecular biology reagents and industrial enzymes. In this chapter, we discuss practical issues guiding the development of crop‐based production systems for molecular farming in plants.
Introduction
Authors: Santharam Sivramiah
Published: July 2004

This chapter briefly discusses the subject matter covered in the section ‘Risk Assessment of Transgenic Crops’ and introduces the articles included therein.
Risk Assessment of Transgenic Plants: Science and Public Policy
Authors: Shantharam Sivramiah , Aubserson‐Huang Lillian
Published: July 2004

Biosafety and the environmental impact of GMOs are among the issues at the heart of the global debate on the suitability and feasibility of agricultural biotechnology. Although principles of risk assessment, which evolved for chemical and engineering disciplines have been extended to biotechnology, with a sprinkling of our incomplete knowledge of ecology and environmental biology, great strides have been made to offer assurance to the public concerning the safety of GMOs in agriculture. Risk assessment of transgenic plants is a discipline under progress and some excellent research has been carried out in the past two decades demonstrating that there is no real evidence for being unduly concerned with their safety. Thanks to risk assessment, our abilities to assess biotechnology, and hence to make informed decisions about the adoption of this technology, have increased greatly. Risk assessment should not be used to stifle technology development, but rather to find ways and means for mitigating those risks and managing them cost effectively.

Clearly, any risk assessment of transgenic plants has to take place within the ambit of sound and consensual public policy framework in which all stakeholders have a say. It is only then that one can promote safe deployment of GMOs for the benefit of all.
Patents and Plant Genetic Resources: The Bonn Guidelines on Access to Genetic Resources and the Patentability of Plant Biotechnological Inventions under the TRIPS Agreement
Authors: Bhatti Shakeel T.
Published: July 2004

This chapter examines the scope of patentable subject matter under Article 27 of the Agreement on Trade‐related Aspects of Intellectual Property Rights (TRIPS agreement) with respect to plant biotechnological inventions and improved plant genetic resources. The chapter reviews the national implementation of the provisions of this Article in 57 patent laws in order to trace what conditions improved plant genetic resources must meet in order to be patentable in different jurisdictions. The chapter also examines interfaces between the implementation of TRIPS standards and the application of access and benefit‐sharing frameworks for plant genetic resources. On the access and benefit‐sharing side, it analyses the relevant provisions of the Convention on Biological Diversity (CBD) and the Bonn Guidelines on access and benefit‐sharing, which were adopted by the Conference of the Parties to the CBD. The chapter then surveys the national and regional implementation of relevant CBD provisions in national and regional access frameworks through a comparative analysis of 35 access and benefit‐sharing laws. The views expressed in this chapter are exclusively those of the author and do not necessarily reflect the views of WIPO, its Secretariat or its member states.
Intellectual Property Rights for Plant Biotechnology: International Aspects
Authors: Boettiger Sara , Graff Gregory D. , Pardey Philip G. , Van Dusen Eric , Wright Brian D.
Published: July 2004

Intellectual property rights (IPR) are important internationally, in public, non‐profit and private institutions, both as incentives for innovation and as constraints on freedom to operate in agricultural research and development. Early 20th century progress in plant breeding and genetics led to the development of hybridisation, which increased yields while providing an important physical means of restricting the reproduction of plant genetic resources. Subsequently, in countries around the world the expansion of ‘intellectual property rights’ (IPR) has created several other means of restricting the reproduction and trading of plant genetic resources.
Cotton and Biotechnology
Authors: Wakelyn P.J. , May O.L. , Menchey E.K.
Published: July 2004

Research is underway to produce transgenic cottons with improved agronomic traits as well as improved fibre quality properties. Generally, the principle concerns among the public about biotechnology are the environmental impact and consumer safety. These concerns eventually may affect cotton yarn and finished textile products as well as pharmaceutical and food products from cotton and cottonseed. Consumers and governments need to be educated on the safety and benefits of transgenic cotton. Specific concerns related to production of transgenic cotton are addressed in this paper.
The Use of Transgenic Papaya to Control Papaya Ringspot Virus in Hawaii, and the Transfer of this Technology to Other Countries
Authors: Gonsalves Dennis , Fermin Gustavo
Published: July 2004

A handful of virus‐resistant transgenic plants have been commercialised in the United States. This communication does not dwell on discussing possible reasons for the lack of other commercial virus‐resistant transgenic plants. Rather it focuses on an analysis of the events involved in development and commercialisation of transgenic papaya that is currently grown in Hawaii to controlPapaya ringspot virus, on the impact of the varieties on the Hawaii papaya industry, on the current status of the Hawaiian transgenic papaya in United States, Canada, and Japan, and on our efforts to transfer this technology to other countries. This paper primarily deals with the rationale and motivations for the commercialisation of transgenic papaya, and to a lesser degree on the technical development of the transgenic papaya.
Adoption of Biotechnology‐Enhanced Crops by Developing Countries
Authors: James Clive
Published: July 2004

Global population reached 6 billion on 12 October 1999, and is expected to reach 9 billion by 2050, when approximately. 90% of the world's population will live, or survive, in the three continents of the South: Asia, Africa and Latin America, where today malnutrition results in 24,000 deaths per day. Thus, in the next 50 years, population will increase by 50 %, or 3 billion, and food production will need to be doubled on the same area of arable land (1.5 billion hectares) by 2050. The magnitude of the challenge of feeding tomorrow's world is difficult to conceive. Crops are the major source of food globally. There is a widely held view in the international scientific and development community that conventional crop improvement alone will not allow us to meet the global food demands of 2050. What is being advocated is a global strategy that integrates both conventional crop improvement and biotechnology, including transgenic crops, which are often referred to as genetically modified (GM) crops.
Agricultural Biotechnology in Africa
Authors: Sasson Albert
Published: July 2004

In Africa, the challenge is not to feed more people, but to do so with less available land, fewer non‐renewable resources and less water. Raising productivity requires the adoption of technologies that increase yields on unfavourable soils, control pre‐harvest pests and decrease post‐harvest losses. The examples given in this chapter show that biotechnologies can benefit farmers and consumers through the increase in farm output, raising the nutritional value of specific crops and livestock, providing employment opportunities and higher income to small holders and landless rural labourers, improving the rural environment by decreasing the use of chemicals and lowering food cost in rural and urban areas.
Crop Biotechnology in India, Thailand, Vietnam, Philippines and Malaysia
Authors: Zehr Usha Barwale
Published: July 2004

Crop biotechnology is providing unique opportunities to produce plants with desired genetic traits, which have been difficult to achieve using conventional techniques. The Philippines and India have approved genetically modified crops for commercialisation. Many other products are also in the regulatory pipeline in a number of Asian countries. Regulatory/Biosafety guidelines are in place in The Philippines, India, Indonesia, Thailand and Malaysia, providing a framework for conducting genetic engineering activities in plants. Vietnam is also in the process of developing regulatory guidelines. Biosafety guidelines are primarily implemented and monitored by various ministries, including the Ministry of Science and Technology, the Ministry of Environment and Forests and the Ministry of Agriculture in most countries that are involved in this process. A number of public and private institutions are working to develop traits including male sterile systems for exploitation of hybrid vigour, tolerance to various biotic and abiotic stresses, improved protein quality, enhanced pro‐vitamin‐A, edible vaccines and others. Genomics research is also being pursued for some indigenous crops with regional value and for which research data at the global level is limited. Investment in the area of biotechnology has increased substantially over recent years, yet greater investment is required for developing and acquiring new technologies for meeting the present and future challenges in agriculture. Enhanced public–private partnerships are also needed. With the current interest in biotechnology within the Asian countries, the region will emerge as a serious participant in biotechnology in the coming years.
Technology Transfer to Developing Countries and Technology Diffusion: The Future Role of Institutions in Capacity Building, Regulations, IPRs and Funding
Authors: Krattiger Anatole F.
Published: July 2004

Contrary to some popular beliefs, technology is not transferred based on needs but is strengthened when scientific and technological capacity exists and when effective regulatory systems are in place (biosafety, intellectual property rights, trade regulations). In the agricultural biotechnology area, a number of institutions facilitate technology transfer through a range of activities and initiatives. Many were created and built when technology transfer was something linear. Today, however, technology development and transfer is highly interactive. These elements are discussed in the context of globalisation and public–private partnerships, among others.

It is concluded that many of today's development institutions that were created over the last half century or so are no longer effective in the new world order. The incremental changes taking place today in changing the institutions are certainly desirable but fail to deliver the full potential of these institutions and investments. A fundamental re‐structuring is long overdue and proposes a number of initiatives to that effect including fundamentally re‐structuring international institutions, leveraging the potential of biotechnology companies through new types of public–private institutional arrangements, unleashing private investments, and addressing the constraints imposed by the over‐regulation of biotechnology. Unfortunately, it appears that the prospects for any of the needed changes to take place are not very good. Perhaps the plight of the world's poor has to become even worse to draw the attention of the developed world and motivate it for action.
Ablative Materials
Authors: Favaloro Michael
Published: July 2004

Ablative materials are used to protect vehicles from atmospheric reentry, to protect rocket nozzles and ship hulls from propellant gas erosion, as protection from laser beams, and to protect land‐based structures from high heat environments. Ablative heatshield materials protect a vehicle from excessive heating, and can also act as a structural component. Thermophysically, ablation involves the elimination of thermal energy by sacrifice of surface material. Some principles of this heat and mass transfer process are melting, conduction and storage of heat in the material substrate, absorption of heat by gases, and exothermic and endothermic chemical reactions. The three groups of ablative materials are subliming or melting ablators, charring ablators, and intumescent ablators. Subliming ablators, eg, Teflon, carbon and composites, act as heat sinks until the surface reaches the sublimation or melting temperature, then removing heat from the insulation material. In the charring ablator, the surface material acts as a heat sink, up to the reaction temperature, where endothermic chemical decomposition into charred material and gaseous products occurs. As the charred surface is eroded, more char forms. Intumescent ablators form a foamlike region on exposure to heat, resulting in improved insulation performance.
Abrasives
Authors: Bange Donna , Gary Roger
Published: July 2004

The term “abrasives” applies to articles and processes that are involved in removal or refinement of a workpiece surface. Abrasive articles are used in a plethora of different processes including: metal de‐gating, grinding, shaping, cutting, deburring, finishing, sanding, cleaning, polishing and planarizing. Today abrasive articles are employed in some aspect in most manufactured goods sold. There are four major forms of abrasive articles. Bonded abrasives are three dimensional composite of abrasive grains dispersed in a bond system; one popular form is a grinding wheel. Coated abrasives are described as a plurality of abrasive grains bonded to a backing. Non‐woven abrasives comprise a plurality of abrasive grains bonded into and onto a porous non‐woven substrate. Loose abrasive slurries comprise a plurality of abrasive grains dispersed in a liquid medium (e.g. water) and are employed in polishing applications to achieve a very fine surface finish. These abrasive articles rely on a broad range of technologies including ceramics, inorganic chemistry, paper, textiles, organic chemistry, polymer science, surface chemistry and related process technologies. As these technologies have grown, so has the advancement of abrasive technologies to create abrasive articles with even higher efficiencies.
Acrylonitrile–Butadiene–Styrene (ABS) Polymers
Authors: Kulich Donald M. , Gaggar S. K. , Lowry V. , Stepien R.
Published: July 2004

Acrylonitrile–butadiene–styrene (ABS) polymers are composed of elastomer dispersed as a grafted particulate phase in a thermoplastic matrix of styrene and acrylonitrile copolymer (SAN). The presence of SAN grafted onto the elastomeric component, usually polybutadiene or a butadiene copolymer, compatabilizes the rubber with the SAN component. Property advantages provided by this graft terpolymer include excellent toughness, good dimensional stability, good processibility, and chemical resistance. The system is structurally complex. This allows considerable versatility in the tailoring of properties to meet specific product requirements. Consequently, research and development in ABS systems is active. Numerous grades of ABS are available, including new alloys and specialty grades for high heat, flaming‐retardant, or static dissipative product requirements. Good chemical resistance combined with the relatively low water absorptivity\documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${(<1\%)}$\end{document}results in high resistance to staining agents. Antioxidants substantially improve oxidative stability. Applications involving extended outdoor exposure require the use of stabilizing additives, pigments, and protective coatings. In manufacturing, grafting is achieved by the free‐radical copolymerization of styrene and acrylonitrile monomers. The commercial processes for manufacturing ABS are discussed. ABS is sold as an unpigmented product for on‐line coloring using color concentrates during molding, or as precolored pellets. ABS can be processed by compression and injection molding, extrusion, calendering, and blow‐molding. Post‐processing operations include cold forming, painting, and adhesive bonding. As a “bridge” polymer between commodity plastics and higher performance engineering thermoplastics, ABS has become the largest selling engineering thermoplastic.
Acetylene from Hydrocarbons
Authors: Gannon Richard E.
Published: July 2004

Acetylene, C2H2, is a highly reactive, commercially important hydrocarbon. Its reactivity is related to its triple bond between carbon atoms and, as a consequence, its high positive free energy of formation. Because of its explosive nature, long distance shipping or pressurized storage is not recommended. Thus acetylene is generally used as it is produced without shipping or storage.

Commercially, acetylene is used primarily as a raw material for the synthesis of a variety of organic chemicals. In the United States, this accounts for about 80% of acetylene usage, with the balance being used for metal welding and cutting. Worldwide acetylene production peaked in the mid‐1960s, after which it declined dramatically as processes were developed to substitute lower cost olefins and paraffins for the acetylene feedstock. Production levels reached a minimum in the early 1980s and since have been growing at a rate of about 2–4% per year, mainly in response to the growth of 1,4‐butanediol production.

Although acetylene production in Japan, China, and Eastern Europe is still based on the calcium carbide process, the large producers in the United States, Western Europe, and Russia now rely principally on the partial oxidation of natural gas. However, much of the incremental growth in production is based on producing acetylene as a coproduct of ethylene in the steam cracking process. As a coproduct, acetylene is much less costly than as produced from partial oxidation or calcium carbide.
Acetylene
Authors: Gannon Richard E. , Manyik Robert M. , Dietz C. M. , Sargent H. B. , Thribolet R. O. , Schaffer R. P.
Published: July 2004

Acetylene, C2H2, is a highly reactive, commercially important hydrocarbon. Its reactivity is related to its triple bond between carbon atoms and, as a consequence, its high positive free energy of formation. Because of its explosive nature, long distance shipping or pressurized storage is not recommended. Thus acetylene is generally used as it is produced without shipping or storage.

Commercially, acetylene is used primarily as a raw material for the synthesis of a variety of organic chemicals. In the United States, this accounts for ∼90% of acetylene usage, with the balance being used for metal welding and cutting. Worldwide acetylene production peaked in the mid‐1960s, after which it declined dramatically as processes were developed to substitute lower cost olefins and paraffins for the acetylene feedstock. 1,4‐Butanediol production accounts for 90% of the demand for acetylene for chemical production.

Although acetylene production in Japan, China, and Eastern Europe is still based on the calcium carbide process, the large producers in the United States, Western Europe, and Russia now rely principally on the partial oxidation of natural gas. However, much of the incremental growth in production is based on producing acetylene as a coproduct of ethylene in the steam cracking process. As a coproduct, acetylene is much less costly than as produced from partial oxidation or calcium carbide.
Acetic Acid
Authors: Wagner Frank S.
Published: July 2004

Acetic acid, CH3COOH, is a corrosive organic acid having a sharp odor, burning taste, and pernicious blistering properties. It is found in ocean water, oilfield brines, rain, and at trace concentrations in many plant and animal liquids, and has a place in organic processes comparable to sulfuric acid in the mineral chemical industries. It is central to all biological energy pathways. Fermentation of fruit and vegetable juices yields 2–12% acetic acid solutions, usually called vinegar. Uses include the manufacture of vinyl acetate, acetic anhydride and terephthalic acid. Vinyl acetate is used to make latex emulsion resins for paints and adhesives. Acetic anhydride is used in making cellulose acetate fibers and cellulosic plastics. About one‐half of the world production comes from methanol carbonylation and about one‐third from acetaldehyde oxidation. Glacial acetic acid is dangerous, but its precise toxic dose is not known for humans. Vinegar, on the other hand, which is dilute acetic acid, has been used in foods and beverages since ancient times.
Acetamide
Authors: Wagner Frank S.
Published: July 2004

Acetamide, C
2
H
5
NO, mol wt 59.07, is a white, odorless, hygroscopic solid derived from acetic acid and ammonia. The melt is a solvent for organic substances; it is used in electrochemistry and organic synthesis. Most commercial routes for the production of acetamide involve dehydration of ammonium acetate. Acetamide has been used experimentally as a source of nonprotein nitrogen for sheep and dairy cattle. It suppresses acid buildup in printing inks, lacquers, and perfumes, is a mild moisturizer, and is used as a softener for leather, textiles, and certain plastics.
Acetyl Chloride
Authors: Wagner Frank S.
Published: July 2004

Acetyl chloride, C
2
H
3
OCl, mol wt 78.50, is a colorless, corrosive, irritating liquid that fumes in air. It reacts very rapidly with water, readily hydrolyzing to acetic acid and hydrochloric acid. Acetyl chloride is toxic. Its high reactivity leads to modifications that block the action of enzymes needed by living tissue. Acetyl chloride is manufactured by the reaction of sodium acetate or acetic acid and phosphorus trichloride. It is a powerful acetylating agent and is used in the manufacture of aspirin, acetaminophen, acetanilide, and acetophenone, and in liquid crystal compositions.
Acrolein and Derivatives
Authors: Etzkorn W. G. , Pedersen S. E. , Snead T. E.
Published: July 2004

Acrolein (C
3
H
4
O), (2‐propenal) is the simplest unsaturated aldehyde

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. The primary characteristic of acrolein is its high reactivity due to conjugation of the carbonyl group with a vinyl group. More than 80% of the refined acrolein that is produced today goes into the synthesis of methionine. Much larger quantities of crude acrolein are produced as an intermediate in the production of acrylic acid. Acrolein is a highly toxic material with extreme lacrimatory properties. Special care in handling is required because of its flammability, reactivity, and toxicity. Acrolein is highly reactive in a variety of reactions, including oxidation and reduction and in reactions with alcohols. Because of its antimicrobial activity, it has found use as an agent to control the growth of microbes in process feed lines.
Acrylic Acid and Derivatives
Authors: Bauer William
Published: July 2004

Acrylic acid (propenoic acid) is prepared using acrolein from the catalytic oxidation of propylene. Acrylates are primarily used to prepare emulsion and solution polymers. The emulsion polymerization process provides high yields of polymers in a form suitable for a variety of applications. Acrylic acid is used in the form of esters. A large amount (80–85%) of raw materials is used in the manufacture of superabsorbent poly(acrylic acid) and its salts are also used in detergents, water treatment, and dispersants. Solution polymers of acrylates are employed in the preparation of industrial coatings. The polymeric products share qualities of high resistance to chemical and environmental attack and attractive strength properties. Acrylic acid and its esters react readily with electrophilic, free‐radical, and nucleophilic agents.
Fibers, Acrylic
Authors: Capone Gary J. , Masson James C.
Published: July 2004

Acrylic fibers are spun from copolymers in which acrylonitrile is the major component. The fibers are solution‐spun from solvents such as dimethylformamide, dimethyl sulfoxide, and sodium thiocyanate–water either by wet (extrusion into a nonsolvent) or dry (extrusion into a hot inert gas) technologies. The basic technologies were developed in the 1950s and first commercialized in the United States. Expansion to Europe and Japan soon followed. In the twenty‐first century, the locus has shifted to Asia, with significant down‐sizing in the United States. An extensive table lists producer capacities.

Acrylic fibers occupy market niches such as sweaters, half‐hose, upholstery, hand knitting yarns, and carbon fiber precursor. The technology that adapts the basic polymer and fiber for each of these products is described. The physical properties of standard acrylic fiber is compared to that of other synthetic and natural fibers in a table. Stress–strain curves are shown under differing conditions. Chemical properties of the fiber such as resistance to acids and bases and flame retardancy is detailed and compared.

Commercial polymer and spinning technologies are explained in detail, including processes for bicomponent and producer‐dyed fiber.
Acrylic Elastomers
Authors: Spelta A. L.
Published: July 2004

Acrylic elastomers (ACMs) are specialty rubbers whose structure shows both the presence of a saturated backbone, which is responsible for the high heat, and oxidation resistance, and the ester side groups, which contribute to the marked polarity of this elastomer family. The first commercial ACMs were produced and introduced in the market in the United States in the 1940s.

The base monomers of modern acrylic rubbers are ethyl acrylate, butyl acrylate, and 2‐methoxyethyl acrylate. These monomers are polymerized by free‐radical catalysts in aqueous suspension and emulsion polymerization. In order to facilitate vulcanization, proper reactive monomers are copolymerized with alkyl and/or alkoxyalkyl acrylates. A large variety of cure‐site monomers has been proposed, but only a few have achieved commercial significance. Two of the most important classes are labile chlorine‐containing monomers and epoxy/carboxyl‐containing monomers.

Acrylic elastomers can be tailor‐made to meet certain performance requirements. The influence of monomer composition on oil resistance and low temperature flexibility has been studied both from the theoretical and experimental point of view. ACMs, as most elastomers, have to be propertly formulated in order to supply valuable performance. Reinforcing filler(s) and other typical rubber ingredients and additives are required. Acrylic elastomers have found commercial applications mainly in automotive non‐tire applications such as: seals, gaskets, valve stem oil deflectors, hose and hose linings, wire and cable jacketing, noise control, and vibration damping.
Actinides and Transactinides
Authors: Seaborg Glenn T. , Hoffman Darleance C. , Lee Diana M.
Published: July 2004

The actinide elements are a group of chemically similar elements with atomic numbers 89 through 103, and include actinium, thorium, protactinium, uranium, neptunium, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium, and lawrencium. Each of the elements has a number of isotopes, all radioactive. Thorium, uranium, and plutonium are well known for their role as the basic fuels (or sources of fuel) for the release of nuclear energy. The importance of the remainder of the actinide group lies at present in research. The actinides present a storage‐life problem in nuclear waste disposal. Only the members of the actinide group through Pu have been found to occur in nature. Thorium and uranium occur widely in the earth's crust in combination with other elements, and, in the case of uranium, in significant concentrations in the oceans. With these exceptions, the actinide elements are synthetic in origin for practical purposes, ie, they are products of nuclear reactions. All the actinide elements are radioactive, and, except for thorium and uranium, special equipment and shielded facilities are usually necessary for their manipulation. Special techniques for experimentation with the actinide elements other than Th and U have been devised because of the potential health hazard to the experimenter and the small amounts available. The actinide elements exhibit uniformity in ionic types. Corresponding ionic types are similar in chemical behavior, although the relative stabilities differ from element to element. Of the actinide ions, the small, highly charged\documentclass{article}\pagestyle{empty}\begin{document}${{\rm{M}}{^{4+}}}$\end{document}ions exhibit the greatest degree of hydrolysis and complex ion formation. The actinide metals, like the lanthanide metals, are highly electropositive. They can be prepared by the electrolysis of molten salts or by the reduction of a halide with an electropositive metal, such as calcium or barium. Thousands of compounds of the actinide elements have been prepared. The elements beyond the actinides in the periodic table can be termed the transactinides. These begin with the element having atomic number 104 and extend, in principle, indefinitely. Nine such elements, numbers 104–1112, are now known, and evidence for the observation of elements 114, 116, and 118 was published in 1999. These reports now await confirmation. Thse elements are synthesized by the bombardment of heavy nuclides with heavy ions. Modern high‐speed computers have made possible the calculation of the electronic structure of the atoms, which gives some general guidance about chemical properties. Recently, the even more difficult theoretical problem of predicting the behavior of molecular species under actual experimental conditions has been addressed using relativistic quantum‐chemical calculations combined with fundamental physicochemical considerations.