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from article Branched polymer
Steps in the synthesis of a starburst polymer. s = surface. o = interior. fr = reactive group. fp = protected group.
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from article Heterocyclic polymer
Structural units in linear polymers. (a) Simple linear polymer. (b) Stepladder polymer. (c) Ladder polymer.
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from article Heterocyclic polymer
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from article Intermolecular forces
Schematic diagram of intermolecular interaction. (a) There is negligible interaction between atoms that are 1 nm apart. (b) For atoms separated by about 0.8 nm or less, attractive dispersion forces result from correlated fluctuations of the electron…
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from article Beef cattle production
Angus bull with overall carcass merit. (Credit: Jim Koch/Agricultural Research Service, U.S. Department of Agriculture)
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from article Beef cattle production
Brahman (zebu) bull (Bos indicus). (Credit: Scott Bauer/Agricultural Research Service, U.S. Department of Agriculture)
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from article Beef cattle production
An exemplary purebred Hereford bull. (Credit: Michael MacNeil/Agricultural Research Service, U.S. Department of Agriculture)
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from article Beef cattle production
A group of Simmental cows. (Credit: Iowa Beef Industry Council)
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from article Beef cattle production
Three Charolais heifers. (Credit: Darcy Vial/Farm Service Agency, U.S. Department of Agriculture)
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from article Beef cattle production
In order to attain market weight, cattle are fed often in feedlots. (Credit: Dave Hughes/Getty Images)
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from article Beef cattle production
In the United States, beef animals used for food must be inspected extensively pre- and postmortem by federal officials. (Credit: Bob Nichols/U.S. Department of Agriculture)
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from article Huntington's disease
Huntington's disease is a hereditary disorder that affects approximately five to ten of every 100,000 persons. The average age at onset is between 35 and 40 years. Invariably fatal, the disease progresses gradually over time. (Copyright ©…
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from article Cheese
Cheese being placed in brining tank (salt bath). (Credit: Westend61/Getty Images)
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from article Cheese
Cheese ripening. (Credit: Tom Paiva Photography/Blend Images)
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from article Cheese
Swiss cheese. (Credit: Tom Paiva Photography/Blend Images)
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from article Fruit, tree
Apple trees growing in an orchard. (Photo by Charles Rondeau)
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from article Fruit, tree
Apple scab on fruit. This disease, caused by the fungus Venturia inaequalis, leads to unsightly blemishes on ripe apples. (Photo courtesy of the University of Georgia Plant Pathology Archive)
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from article Fruit, tree
Brown rot, caused by the fungus Monilinia fructicola, on a peach. (Photo by Jonas Janner Hamann, Universidade Federal de Santa Maria, Brazil)
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from article Fruit, tree
Fire blight, caused by the bacterium Erwinia amylovora, on apple fruits and leaves. (Photo courtesy of the University of Georgia Plant Pathology Archive)
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from article Fruit, tree
Blue mold (Penicillium italicum) on a rotting orange. (Photo by G. L. Barron)
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from article Belladonna
Close-up view of the belladonna plant (Atropa belladonna), showing the leaves and berries, which are toxic. (Photo courtesy of Leo Michels)
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from article Lignin-degrading fungi
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from article Lignin-degrading fungi
Close-up view of Pleurotus spp. fruiting bodies growing naturally on a dead tree log. The common name of oyster mushroom comes from the shell-like appearance of the fruiting body. Note the characteristic eccentric caps.
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from article Nitrogen oxides
Nitrogen-oxide structures. Blue = nitrogen. Red = oxygen.
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from article Lychee
Fruit and leaves of lychee (Litchi chinensis). (Photo courtesy of Forest and Kim Starr)
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from article Sterilization
Diagrammatic sketch of an autoclave. (American Sterilizer Co.)
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from article Sterilization
Cobalt-60 furnace which is designed for experimental food sterilization.
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from article Sterilization
Van de Graaff generator principle; packaged products sterilized by means of a high-intensity electron beam which penetrates packages. (After W. M. Urbain, Food Eng., vol. 25, February 1953)
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from article Food allergy
Children (under the age of 18) who experience food allergies are more likely to experience other allergic conditions, including asthma (black), eczema/skin allergy (blue), and respiratory allergy (green). (Credit: National Center for Health…
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from article Food allergy
Allergic responses (immunological responses mediated by the IgE class of immunoglobulins) can be caused by certain foods. In a person with allergies, mast cells will be coated with IgE against one or a few antigens (allergens) that, upon entering…
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from article Food allergy
Peanuts are a common trigger of food allergies in both adults and children. (Credit: Christian Jung/Shutterstock)
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from article Sport-related concussion
Sport-related concussion is among the most frequent injuries experienced by athletes participating in contact and collision sports, including football. (Credit: skynesher/Getty Images)
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from article Sport-related concussion
Medical imaging and scanning techniques can identify the brain areas affected by a sport-related concussion. (Credit: Puwadol Jaturawutthichai/Shutterstock)
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from article Sport-related concussion
A football helmet with anticoncussion padding. This type of helmet is recommended for youths who are active in contact and collision sports. (Copyright © McGraw-Hill Education)
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from article Prairie dog
Black-tailed prairie dogs (Cynomys ludovicianus). (Photo by Ron Singer, U.S. Fish and Wildlife Service)
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from article Alicyclic hydrocarbon
Internal bond angles (α) for (a–c) planar rings and (d) a tetrahedral carbon atom.
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from article Alicyclic hydrocarbon
Nonplanar (a) chair and (b) boat structures of cyclohexane.
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from article Alcohol
Ethanol production plant. (Credit: Julie Kendall/Getty Images)
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from article Alcohol
E85 is a gasoline-ethanol blend containing 51 to 83% ethanol. It is used in flexible-fuel vehicles, which can operate on gasoline or blends of gasoline and ethanol. About 20 million flexible-fuel vehicles are operating in the United States. (Credit:…
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from article Fluids
Probability of finding molecular centers at various separations in gases, liquids, and solids.
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from article Fluids
Conditions of pure-component phase behavior.
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from article Fluids
Behavior of pure-component pressures with density at various temperatures.
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from article Fluids
Behavior of pure-component compressibility factors with pressure at various temperatures.
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from article Fingerprint identification
Typical inked fingerprint.
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from article Fingerprint identification
FBI fingerprint impressions from the investigation train bombing, March 22, 2004, Madrid Spain. (a) Charted fingerprint collected from Mayfield. (b) Charted latent finger print from the crime scene.
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from article Taxonomy
Taxonomies are hierarchical classifications of groups within groups. As an example, the common taxonomic ranks (domain, kingdom, phylum, subphylum, class, order, family, genus, and species) and their respective names for the eastern gray squirrel…
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from article Taxonomy
Taxonomies can be based on traditional phylogenies and cladistic classifications. (Copyright © McGraw-Hill Education)
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from article Desertification
Overgrazing on North American rangelands contributes to soil compaction and alters the composition of vegetation. (Credit: Thomas Wikle)
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from article Desertification
Desertification can be accelerated by cultivation in areas better suited for herding, such as this field in Ethiopia. (Credit: Thomas Wikle)
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from article Desertification
Grazing animals have contributed to desertification in Africa’s Sahel region. (Credit: Thomas Wikle)
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from article Binocular vision disorders
Exotropia (simulated photographically) is a misalignment of the eyes. In this type of manifest strabismus, one or both eyes turn outward. (Credit: Kerri McTigue)
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from article Binocular vision disorders
Esotropia (crossed eyes; simulated photographically) is a type of manifest strabismus in which one or both eyes turn inward. (Credit: Kerri McTigue)
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from article Synaptic transmission
Synaptic transmission enables a neuron to communicate with a target cell across a synapse. During synaptic transmission, a presynaptic neuron releases a neurotransmitter, which then binds to specific postsynaptic receptors. (Copyright © McGraw Hill)
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from article Synaptic transmission
Types of synapses: (a) an electrical synapse, showing the plasma membranes of the presynaptic and postsynaptic cells linked by gap junctions; (b) a chemical synapse, showing neurotransmitters released by the presynaptic cell diffusing across the…
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from article Synaptic transmission
Ultrastructure of exocytosis at the neuromuscular junction. (a) Thin-section electron micrograph of a neuromuscular junction from the sartorius muscle of a resting frog. Vesicles are clustered in the presynaptic terminal at one of many active zones;…
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from article Noradrenergic system
Chemical structure of norepinephrine (C8H11NO3).
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from article Noradrenergic system
The relationship between norepinephrine and G proteins. Binding of norepinephrine to a receptor leads to activation of G proteins, which in turn modulate the activity of other proteins (enzymes or ion channels) in the cell. Terms: ATP, adenosine…
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from article Laminariales
Laminaria: (a) sporophyte; (b) cross section of blade, showing a sorus of unilocular sporangia interspersed with sterile hairs (paraphyses); (c) zoospore; (d) male gametophyte with antheridia; (e) antherozoid (sperm); (f) female gametophyte with…
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from article Laminariales
Giant kelp (Macrocystis pyrifera) can grow up to 0.6 m (2 ft) per day. Note the series of frond blades, with each subtended by a bladder. (Photo courtesy of Charlotte Stevenson, University of Southern California Sea Grant, Los Angeles)
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from article Biosynthesis
Biosynthetic relationships of some natural products. Specific examples which belong to the various classes are given in brackets.
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from article Thulium
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from article Epidermal ridges
Characteristics of individual ridges and their configurations, seen in a print. (After H. Cummins and C. Midlo, Fingerprints: Palms and Soles, McGraw-Hill, 1943)
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from article Obesity
Map of the United States showing the growing prevalence of obesity. In general, the South had the highest prevalence of obesity, followed by the Midwest, the Northeast, and the West. (Credit: U.S. Centers for Disease Control and Prevention)
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from article Obesity
Colored scanning electron micrograph (SEM) of fat (adipose) tissue. The round fat cells (adipocytes) are surrounded by collagen fibers. Lipid is colored purple. Empty cells are seen at top right. (Credit: Science Photo Library/Alamy Stock Photo)
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from article Obesity
Estimated percentage of obesity according to gender. Dark color indicates the percentage of obesity in females; light color indicates the percentage of obesity in males. (Credit: National Institute of Diabetes and Digestive and Kidney Diseases,…
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from article Chemistry
Periodic table. (Jaap Hart/Getty Images)
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from article Fertilization (animal)
Photomicrograph (tinted green) of mouse sperm bound to the zona pellucida of an unfertilized egg under laboratory conditions (in vitro). (Credit: K. O. Kalthoff)
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from article Fertilization (animal)
Mammalian sperm (a) adhering to the zona pellucida, (b, c) undergoing the acrosome reaction, and (c, d) penetrating the zona pellucida on its way to the egg cell proper. (Copyright © McGraw Hill)
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from article Mercury (element)
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from article Mercury (element)
Mercury droplets exhibiting non-wetting of the surface. (Credit: A. Cerar/Getty Images)
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from article Mercury (element)
Tooth with a silver-amalgam filling. (Credit: Szasz-Fabian Jozsef/Shutterstock.com)
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from article Bluegrass
Kentucky bluegrass (Poa pratensis). (Photo courtesy of Forest and Kim Starr)
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from article Pigmentation
Colorful flower of Mirabilis jalapa. The colors of the flowers of this plant can vary as a result of different plant pigments. (Credit: F. D. Richards)
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from article Pigmentation
Zebrafish are often studied as model organisms for research dealing with skin pigmentation. (Credit: Lynn Ketchum/Oregon State University)
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from article Neurohypophysis hormone
Structure of neurohypophysial hormones. Each neurohypophysial hormone is made up of nine amino acid residues with two half cysteines joined by a disulfide bridge to form a ring structure. Vasotocin is found in fishes and fetal pituitaries, while…
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from article Peroxisome
Electron micrograph of a cell of Yarrowia lipolytica (a type of yeast) grown in fatty acid–containing medium. (Copyright © McGraw Hill)
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from article Bipolar disorder
Prevalence of bipolar disorder in adults. The bar graph shows the percent of the U.S. adult population affected by bipolar disorder as it relates to age. (Credit: National Institute of Mental Health)
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from article Enzyme inhibition
Enzyme inhibition often works by preventing a substrate from attaching to an active enzyme. In this example, E1 is one of three sequential enzymes that will convert a substrate (S) into a product (P). However, the product that is created can then…
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from article Enzyme inhibition
Two types of reversible enzyme inhibition. (Left) In competitive inhibition, the inhibitor interferes with the active site of the enzyme, so the substrate is unable to bind to it. (Right) In noncompetitive inhibition, the inhibitor changes the…
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from article Organic conductor
Structures of organic conductors. (a) Electron donors. (b) Acceptor molecule (TCNQ) and two monovalent anions. Abbreviations are explained in the text.
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from article Organic conductor
Stacking of charge-transfer compounds. (a) Segregated stacking of TTF-TCNQ-like materials. (b) Typical zigzag stacking of the (TMTSF)2X series.
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from article Organic conductor
Comparison of the range of electrical conductivities of some AsF5-doped conducting polymers with some metals, semiconductors, and nonconducting polymers.
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from article Organic conductor
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from article Sandalwood
Coast sandalwood (Santalum ellipticum) of Hawaii. (Photo courtesy of Forest and Kim Starr)
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from article Neuroeconomics
Neuroeconomics applies neuroscientific tools and methodologies to investigate the decision making that occurs inside the brain. (Credit: James Steidl/SuperStock)
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from article Alpine vegetation
Forest-alpine tundra near Hyndman Cirque, Idaho. The trees change in density and form within the ecotone beyond the boundary of the timberline upslope toward the alpine tundra. The distribution of timberline, treeline, and the ecotone is irregular…
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from article Alpine vegetation
Whitebark pine (Pinus albicaulis) showing the classic dwarfed and contorted image of trees within the windswept forest-alpine tundra ecotone of the Beartooth Plateau, Wyoming. (Courtesy of T. Crawford)
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from article Alpine vegetation
Flagged tree, mainly supporting branching on the leeside of the upper trunk; needles have been lost from the lower trunk to the parasitic snow fungus. (Courtesy of T. Crawford)
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from article Killer whale
Killer whales (Orcinus orca) in the waters off Alaska. (Credit: David Ellifrit/Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration)
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from article Killer whale
The tail of a killer whale. (Credit: Janice Waite/Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration)
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from article Lysosome-related organelles
Recruitment of cargo molecules into clathrin-coated vesicles at the trans-Golgi network (TGN) for delivery to incipient lysosomes or lysosome-related organelles. In the TGN, soluble lysosomal or lysosome-related organellar proteins (cargos) bind to…
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from article Psychological resilience
Psychological resilience refers to positive adaptation among individuals at risk for maladjustment. There are three classes of protective factors that help people to thrive in the face of significant adversities: support from close family and…
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from article Psychological resilience
The strongest predictor of resilient adaptation is the quality of an individual's close, personal relationships. In general, positive relationships help individuals to combat adversity through collective problem solving and through the sharing of…
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from article Bluestem grass
Big bluestem (Andropogon gerardii). (Photo by Lynn Betts, Natural Resources Conservation Service, U.S. Department of Agriculture)
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from article Bluestem grass
Seed heads of little bluestem (Schizachyrium scoparium). (Photo by Lynn Betts, Natural Resources Conservation Service, U.S. Department of Agriculture)
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from article Hydrido complexes
Structure of ReH92−.
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from article Hydrido complexes
Structure of [HMn(CO)5].
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from article Hydrido complexes
Structure of [HRe(C5H5)2]. The aromatic C5H5 groups are represented by pentagons.
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from article Hydrido complexes
Hydridophosphine structures, with the C6H5 groups not shown. (a) [HRuCl(P{C6H5 }3)3]. (b) [H3Ir(P{C6H5 }3)3].
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from article Hydrido complexes
Reaction scheme for hydrogenation of an olefin using Wilkinson's catalyst.
