bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biopolymers, Analytical Techniques
Authors: Ward Timothy 
Published: July 2004

AbstractAnalytical techniques that utilize biopolymers, ie, natural macromolecules such as proteins, nucleic acids, and polysaccharides that compose living substances, represent a rapidly expanding field. The number of applications is large, eg, chiral chromatography, immunology, and biosensors, among others. Direct chiral resolution by liquid chromatography (lc) involves diastereomeric interactions between the chiral solute and the chiral stationary phase. Because biopolymers are chiral molecules and can form diastereomeric interactions with chiral solutes, they are ideal for use as chiral stationary phases. This property has led to a rapid growth of chromatographic stationary phases utilizing biopolymers to separate chiral molecules. Biopolymers are employed in many immunological techniques, including the analysis of food, clinical samples, pesticides, and in other areas of analytical chemistry. Immunoassays are specific, sensitive, relatively easy to perform, and usually inexpensive. One condition that must be met for the application of an immunochemical method is the stimulating of an immune response leading to the formation of antibodies in the immunized animal. These antibodies can then be isolated and used as highly specific analytical reagents (immunoassays). Analytes that can combine with the corresponding antibodies are called antigens. In general, large, rigid, chemically complex molecules make good antigens. Antibodies are proteins, found in many body fluids such as tears, saliva, and urine, that are present in highest concentrations in blood serum. The particular proteins which exhibit antibody activity are the immunoglobulins (Ig). Biologically derived polymers can be used as highly selective immobilized reagents in analytical applications. The immobilized enzyme electrode is the most common immobilized biopolymer sensor, consisting of a thin layer of enzyme immobilized on the surface of an electrochemical sensor. The advantages of immobilized enzyme electrodes include minimal pretreatment of the sample matrix, small sample volume, and the recovery of the enzyme for repeated use. Enzyme immunosensors are enzyme immunoassays coupled with electrochemical sensors. Enantiomeric separations are expected to continue to have a considerable economic impact on the development of new drugs and therapy in the biomedical field. The importance of immunoassays for food monitoring and in the detection of diseases is expected to continue to grow. The development of biosensors is expected to benefit monitoring therapeutic drug levels, office testing, and implantable devices because of the advantages of cost‐saving automation and improved data handling.
Growth Regulators, Animal
Authors: Beermann Donald H. 
Published: July 2004

AbstractGrowth regulation in animals involves complex interactions among several hormone and growth factor systems that are programmed genetically and modified by diet and the environment to determine rates of tissue and organ growth. Cell number, cell size and cell function are all influenced by these factors and result in significant variation in phenotypic characteristics of animals used for food production. Intervention strategies to enhance efficiency and composition of growth in meat animals were developed once control of metabolic processes was achieved. Four general classes of animal growth regulators have evolved. This article discusses chemical characteristics, mechanism of action and dose response relationships of representative products, and lists those approved by the Food and Drug Administration for growth intervention. Anabolic steroid implants are used in growing finishing cattle to enhance growth rate and efficiency. Ionophores are used in finishing cattle to enhance efficiency of gain. Subtherapeutic feeding of antibiotics to protect or improve animal health are declining in use. Two classes of metabolism modifiers, beta‐agonists and somatotropin, regulate growth primarily by enhancing skeletal muscle growth and concurrently reducing the rate of adipose tissue growth, with species and compound specificity that are significant. Both result in improved efficiency of growth when composition of gain is improved.
Genetic Engineering, Animals
Authors: Lucy Matthew C. 
Published: July 2004

Abstract
Embryo splitting and cloning by nuclear transfer are methods to mass‐produce identical copies of a single embryo or a single adult animal. A transgenic animal may have a stable modification, a stable deletion, or a stable insertion of a foreign gene into its genome. Transgenic animals can be classified as traditional transgenics where a gene is inserted at a random location in the genome or gene‐targeted transgenics (knock‐outs, knock‐ins, and conditional knock‐outs) where a specific gene within the genome is modified. Traditional transgenics are created by pronuclear microinjection, retroviral infection, sperm‐mediated gene transfer, or nuclear transfer. Gene targeting is done by using embryonic stem cells (mice) or somatic cells (farm animals). A DNA targeting vector is constructed that is designed to insert itself into the embryonic genome and inactivate a specific gene. Transgenic and gene targeted animals have become mainstays for scientific research. Transgenic farm animals are essential for the low‐cost production of recombinant proteins. The productivity of farmers may be improved through the use of transgenic farm animals. Pigs with deleted immune recognition genes may soon provide organs for transplantation into humans. Transgenic and gene targeted mice represent some of the most important tools for biomedical research in the twenty‐first century. To understand the function of a specific gene, a transgenic mouse is created that overexpresses the gene. Gene targeting is a step beyond simple overexpression of genes because the function of a gene is accessed by evaluating the phenotype of the gene‐deleted mouse. Conditional knock‐out mice may represent the final step in the evolution of genetic modification of animals.
Initiators, Anionic
Authors: Quirk Roderic P. , Monroy Victor M. 
Published: July 2004

Abstract

Anionic initiators for chain‐reaction polymerization are described. The general relationship between monomer structure, p

K
a
,

and appropriate initiating species is discussed. The scope and limitations of the use of alkali metals, aromatic radical anions, alkyllithium compounds, diphenylmethyl carbanions, fluorenyl carbanions, enolate anions, and alkoxides as initiators is presented. The uniqueness of alkyllithium initiators in hydrocarbon solvents for controlled living anionic polymerization is discussed.
Hormones, Pituitary‐Like Hormones
Authors: Matteri Robert L. 
Published: July 2004

AbstractHormones with structural and functional similarities to the hormones of the anterior pituitary gland fall into two main categories, ie, proteins of the prolactin/growth hormone (PRL/GH) family, and glycoproteins. Anterior pituitary‐like hormones are produced in the placenta by chorionic tissue, and so are normally found in the female during pregnancy. Placental lactogens, members of the PRL/GH family, support growth and development of mammary tissue in preparation for lactation. Chorionic gonadotropin is similar in structure to luteinizing hormone and supports the maintenance of early pregnancy. Chorionic gonadotropin is found in humans and lower primates, as well as in horses. Information on primary structure and commercial sources is provided when available.
Anthraquinone
Authors: Cofrancesco A. J. 
Published: July 2004

AbstractObtaining anthraquinone by oxidizing anthracene with bichromate and sulfuric acid later became the first commercial method for the manufacture of anthraquinone from anthracene. For many years, anthraquinone provided the dyestuff industry with one of the greatest and most prolific building blocks for the manufacture of valuable dyestuffs noted for their outstanding fastness properties. However, in recent times production has fallen off considerably due to the high cost of manufacturing and the discovery of other classes of dyestuffs with good fastness properties. When sublimed, anthraquinone forms a pale yellow, crystalline material, needlelike in shape. It melts at 286°C and boils at 379–381°C. At much higher temperatures, decomposition occurs. Anthraquinone has only a slight solubility in alcohol or benzene and is best recrystallized from glacial acetic acid or high boiling solvents such as nitrobenzene or dichlorobenzene. It is very soluble in concentrated sulfuric acid. In general, anthraquinone is a relatively inert compound exhibiting stability toward oxidation. Only the reduction products involving the keto groups are of any academic or industrial importance. In the dyestuff industry, anthraquinone still ranks high as an intermediate for the production of dyes and pigments having properties unattainable by any other class of dyes or pigments. At this writing (1993) the only two processes for its production are by the Friedel‐Crafts reaction utilizing benzene, phthalic anhydride, and anhydrous aluminum chloride, and by the vapor‐phase catalytic oxidation of anthracene, the latter being preferred. Anthraquinone is a comparatively safe compound. It is a mild allergen and may cause skin irritation. It presents only a slight fire hazard on exposure to heat. The use of benzene in the Friedel‐Crafts process presents serious safety and health problems. Besides its major use in the manufacture of intermediates for anthraquinone dyes and pigments, anthraquinone is finding increasing interest as a catalyst in wood pulping in polymerization of various materials for plastics, and in the isomerization of vegetable oils.
Antioxidants, Polymers
Authors: Thomas Richard , Dexter Martin , King R. E. 
Published: July 2004

AbstractAntioxidants are used to retard the reaction of organic materials with atmospheric oxygen. Such reaction can cause degradation of the properties of the polymer; loss of flavor and development of rancidity in foods; and a change in lubricants. The need for antioxidants depends on the chemical composition of the substrate and the conditions of exposure. High concentrations of antioxidants, ie, 0.5–2% based on the weight of he polymer, are used to stabilize polymers such as natural rubber and polyunsaturated oils. Saturated polymers have greater oxidative stability and require relatively low concentrations of stabilizers; ie, 0.01–0.05%, based on the weight of the polymer. The mechanism by which an organic material (RH) undergoes autoxidation involves a free‐redical chain reaction. High concentrations are also required in substrates that are highly sensitive to oxidation, such as unsaturated elastomers and acrylonitrile–butadiene–styrene (ABS). Thermally induced homolytic decomposition of peroxides and hydroperoxides to free radicals increases the rate of oxidation. Decomposition to nonradical species removes hydroperoxides as potential sources of oxidation initiators. The selection of an antioxidant or system of antioxidants is dependent on the polymer and the anticipated end use. Low concentrations of antioxidants ( < 0.01%) are added to polyethylene and polypropylene after synthesis and prior to isolation to retard oxidation of the polymers exposed to air. Polyunsaturated elastomers are sensitive to oxidation. Antioxidants are added to the elastomers prior to vulcanization to protect the rubber during drying and storage. Nonstaining antioxidants may be used. Staining antioxidants are preferred for the manufacture of tires. Gasoline and jet engine fuels contain unsaturated compounds that oxidize on storage, darken, and form gums and deposits. Radical scanvengers and alkylated paraphenylene diamines are used as stabilizers. Lubricants for gasoline engines are required to withstand harsh conditions. Relatively high concentrations of primary antioxidants and synergists are used to stabilize lubricating oils. The oxidation of food containing fats and oils results in a loss of sensory appeal and eventually rancidness. The U.S. Food and Drug Administration (FDA) regulations covering the use of direct food additives are stringent and few new materials have been regulated. The most commonly used materials are butylated hydroxytoluenen‐propyl gallatte, α‐tocopherol, and butylated hydroxyanisole. A number of antioxidants have been accepted by the FDA as indirect additives for polymers used in food applications.
Antibacterial Agents, Overview
Authors: Macielag Mark J. , Bush Karen , Weidner‐Wells Michele A. 
Published: July 2004

AbstractAntibacterial agents are synthetic compounds that kill or prevent the growth of bacteria. They exhibit selective toxicity to bacterial cells either because they inhibit a biochemical target present solely in bacteria or because they exhibit greater affinity for the bacterial target than the mammalian counterpart. Antibacterial agents are used in the treatment and/or prevention of infections due to pathogenic bacteria in humans and animals. The search for synthetic antiinfective agents began in the early 1900s with Paul Ehrlich's pioneering research on organoarsenicals. Currently, five classes of synthetic antibacterial agents are marketed for therapeutic use: the antitubercular agents, nitrofurans, oxazolidinones, quinolones, and the sulfonamides and combinations. Taken as a whole, drugs from these classes are used to treat a broad range of bacterial diseases, including tuberculosis, urinary tract infections, respiratory tract infections, and infections due to multidrug‐resistant bacteria. Emergence of resistance has limited the usefulness of the antitubercular agents and sulfonamides as sole therapy. The nitrofurans and the oxazolidinones have found their own niches, principally in the treatment of urinary tract infections and serious gram‐positive infections, respectively. The quinolones, by virtue of their broad spectrum of antimicrobial activity, oral bioavailability, good tissue distribution, and well‐understood safety profile, retain a prominent position in the armamentarium of antibacterial drugs.
Furnaces, Electric, Arc Furnaces
Authors: Cotchen J. Kevin 
Published: July 2004

AbstractFurnaces, Electric, Arc Furnaces. J. Kevin Cotchen (MAN GHH Corp.). Arc furnaces used in electric melting, smelting, and electrochemical operations are of two basic designs; indirect and direct arc. The arc of the indirect‐arc furnace is maintained between two electrodes and radiates heat to the charge. The arcs of the direct‐arc furnace are maintained between the charge and the electrodes, making the charge a part of the electrical power circuit. Not only is heat radiated to the charge, but the charge is heated directly by the arc and the current passing through the charge.Indirect‐arc furnaces have been used primarily in foundries for melting copper, copper alloys, and other nonferrous metals that have a low melting point. Direct‐arc furnaces include open‐arc furnaces, d‐c arc furnaces; submerged arc‐furnaces; and arc‐resistance furnaces. All new furnace installations require pollution control equipment. This normally consists of off‐gas afterburning (sometimes with energy recovery), and dust collection equipment, typically a baghouse.
Paint, Architectural
Authors: Leman Arthur A. 
Published: July 2004

Abstract
Paint is one of the most common and widely used materials in home and building construction and decoration. This broad use comes from paint's ability to provide improved appearance, decoration, as well as protection of the substrate to which it is applied. Paint is defined as “any liquid, liquefiable, or mastic composition designed for application to a substrate in a thin layer which is converted to an opaque solid film after application.” This article focuses on the types of paints commonly referred to as architectural coatings, house paints, or trade sales paints.
Familiar coatings cover a wide range of products such as paints, primers, stains, varnishes, and sealers. Most paints are available in a wide variety of colors and appearances, and are made up of four basic groups of chemical raw materials: binders or resins, pigments, solvents, and additives. Proper choice and amount of both binder and pigments, as well as the volume relationships between the two, govern the overall performance properties of paints. The manufacture of house paints involves mixing together these raw material ingredients in such a way that the finished paint is a homogeneous mixture of evenly distributed ingredients. Along with the formulation and manufacture of high quality paint, proper surface preparation and correct application of house paints are important for good durability and performance.
Polyethers, Aromatic
Authors: White Dwain M. 
Published: July 2004

Abstract
The aromatic polyethers described in this article are engineering thermoplastics which have excellent physical properties and desirable high temperature properties. Two general classes of materials are described. One class of polyethers comprises polymers with only arylene ether linkages in the backbone, ie, the 1,4‐polyphenylene oxides. The principal commercial material, poly(2,6‐dimethyl‐1,4‐phenylene oxide) is prepared by oxidative coupling polymerization of 2,6‐dimethylphenol. Its synthesis, reaction mechanism, and properties are described. In addition, compatible blends of poly(phenylene oxides) with polymers such as polystyrene, as well as other types of blends, are mentioned. A second general class of aromatic polyethers that is covered consists of materials containing alternating sequences of polyarylene ethers and other arylene units which are linked by functional groups other than ethers. The latter group includes the commercial materials: polyethersulfones, polyetherketones, and polyetherimides. Syntheses and properties of these are presented.
Ascorbic Acid
Authors: Kuellmer Volker 
Published: July 2004

AbstractVitamin C was the first vitamin to be manufactured by chemical synthesis on an industrial scale, and today more vitamin C is produced than any other vitamin. Major suppliers of vitamin C are Hoffmann‐La Roche, BASF, Takeda, and Merck‐Darmstadt. Additional production occurs in Eastern Europe, India, and China. Most of the current industrial production is based on the efficient second synthesis developed by Reichstein and Grüssner in 1934. Various attempts to develop a superior, more economicalL‐ascorbic acid process have been reported since 1934. Much time and effort has been developed to find other methods of vitamin C synthesis by fermentation. The use of the fermentation process for the cost‐effective production ofL‐ascorbic acid, however, requires further improvement.Both epidemiological and biochemical studies indicate that vitamin C may play an important role in the prevention of cancer, cataracts, and other disorders. However, there are many gaps in the knowledge of vitamin C, eg, in its role in nutritional interrelationships and in metabolic interactions, as well as its role in prevention of various diseases in humans.Although much additional knowledge concerning the various factors affecting the ascorbic acid status of humans has been acquired in the past decade, the optimum ascorbic acid intake necessary to maintain peak physical and mental health still needs to be established.
Antiparasitic Agents, Avermectins
Authors: Fisher Michael H. , Mrozik Helmut 
Published: July 2004

AbstractIn 1976 scientists at the Merck Corporation discovered a complex of eight closely related natural products, subsequently named avermectins A1athrough B2b, in a culture ofStreptomyces avermitilisMA‐4680 (NRRL8165) originating from a soil sample collected at Kawana, Ito City, Japan and isolated by the Kitasato Institute. Designated A1a(C49H74O14), A1b(C48H72O14), A2a(C49H76O15), A2b(C48H74O15), B1a(C48H72O14), B1b(C47H70O14), B2a(C48H74O15), and B2b(C47H72O15), they are among the most potent anthelmintic, insecticidal, and acaricidal compounds known. Two avermectins, abamectin (the avermectin B1) and ivermectin, which is saturated at C‐22–C‐23, have been commercialized to date. Avermectin B1is the most effective of the avermectin family of natural products against agriculturally important insects and mites. Ivermectin is active against two significant phyla of animal parasite: the Nemathelminthes or nematodes (roundworms) and the Arthropoda (insects, ticks, and mites). Avermectins are highly lipophilic substances and dissolve in most organic solvents. Avermectin B1and ivermectin both contain two secondary and one tertiary hydroxy group. The two secondary alcohols are readily acetylated with acetic anhydride in pyridine. Avermectin B1and ivermectin have two secondary hydroxy groups susceptible to oxidation to the corresponding ketones. Ivermectin (,23—dihydroavermectin B1) is obtained by catalytic reduction of avermectin B1. Methylation of avermectins B1and B2leads to the corresponding derivatives of the A series. The worldwide acceptance of ivermectin in livestock production and health care of companion animals has made it the largest selling animal health drug. Abamectin is in commercial use as an agricultural pesticide and its applications are continuing to expand.
Azine Dyes
Authors: Smith Roy E. 
Published: July 2004

AbstractAzine, oxazine, and thiazine dyes were among the earliest of synthetic dyes. The names are derived from the 6‐member heterocyclic ring system present in all dyes of these classes: 1,4‐diazine, 1,4‐oxazine, and 1,4‐thiazine. Azine, oxazine, and thiazine dyes were historically more important than they are at present. However, at least one example of each, introduced more than 100 years ago, is still offered commercially today. Azo and anthraquinone dyes have largely displaced them in commercial application. Azo dyes offer better fastness and broader shade ranges at more economical prices. Azine dyes are used extensively as biological stains. Colors are mostly yellow to red. Oxazine dyes have seen use as laser dyes and titration indicators. Oxazine dyes containing sulfonic acid groups are claimed to be suitable for dyeing leather in brown shades. Methylene Blue CI Basic Blue 9(CI 52015), is the classic thiazine dye still in use today. Thiazine is not important in dyes as such, but it is a part of some reactive dyes.
Sugar, Beet Sugar
Authors: Cleary Michael 
Published: July 2004

Abstract
Sugar beets, grown in temperate climates predominately in the northern hemisphere, provide about one‐third of the world sugar supply and about half of the U.S. requirements. The crop is usually harvested at the end of the growing season and held in large storage piles until processing. The beet root, weighing 1–2 kg, contains 12–20% sucrose, 70–75% water, 2% other solubles, and ca 5% insoluble material, which is eventually dried and sold as an animal feed by‐product. The beets are sliced, the solids extracted countercurrently, the juice purified with lime and carbon dioxide then filtered and concentrated, and the sucrose recovered by crystallization in vacuum pans. The final mother liquor, molasses which is about 50% sucrose, may be sold as a by‐product or subjected to chromatographic separation to further recover sucrose and occasionally betaine. Markets for the present and near terms are steady or increasing at a rate of 3–4% per year whereas prices are flat. Although some market segments seem to prefer cane sugar over beet sugar, competitive advantages in the United States depend mainly on the ability to produce and deliver the product at the lowest cost.