bluuebunny/crossref_metadata_2025 huggingface dataset:
Chlorofluorocarbon Sources of Environmental Contamination
Authors: Howard Philip H. , Hanchett Arnold
Published: October 2006

The quantities of chlorofluorocarbons (FCC's) used commercially in the United States and globally are reviewed, and estimates of environmental release from the applications are made. The results indicate that sizable quantities of the FCC's that have been produced have not yet reached the environment and that regulation of U.S. applications would partly reduce, but not end, the possible destruction of stratospheric ozone.
Blockade of Acetylcholine Receptors: A Model of Myasthenia Gravis
Authors: Satyamurti S. , Drachman Daniel B. , Slone Fred
Published: October 2006

In order to block acetylcholine receptors of muscle, the alpha toxin of the Formosan cobra (
Naja naja atra
) was given intravenously to rats. Electrophysiological and pharmacological changes typical of myasthenia gravis were recorded, including decremental responses to repetitive stimuli, curare sensitivity, neostigmine reversal, and posttetanic phenomena. This model supports the concept that a reduction of available acetylcholine receptors may play an important role in myasthenia gravis.
2,3-Diphosphoglycerate in Erythrocytes of Chick Embryos
Authors: Isaacks Russell E. , Harkness Donald R.
Published: October 2006

2,3-Diphosphoglycerate, heretofore considered absent in avian erythrocytes, occurs in the erythrocytes of embryos to the extent of 4 to 5 micromoles per cubic centimeter of erythrocytes before hatching; it disappears from the cells within 8 days after the embryo hatches.
Earth's Early Atmosphere
Authors: Kasting James F.
Published: October 2006

Ideas about atmospheric composition and climate on the early Earth have evolved considerably over the last 30 years, but many uncertainties still remain. It is generally agreed that the atmosphere contained little or no free oxygen initially and that oxygen concentrations increased markedly near 2.0 billion years ago, but the precise timing of and reasons for its rise remain unexplained. Likewise, it is usually conceded that the atmospheric greenhouse effect must have been higher in the past to offset reduced solar luminosity, but the levels of atmospheric carbon dioxide and other greenhouse gases required remain speculative. A better understanding of past atmospheric evolution is important to understanding the evolution of life and to predicting whether Earth-like planets might exist elsewhere in the galaxy.
Sea-Floor Hydrothermal Activity Links Climate to Tectonics: The Eocene Carbon Dioxide Greenhouse
Authors: Owen Robert M. , Rea David K.
Published: October 2006

Two important findings of recent ocean-floor drilling in the southeast Pacific (Deep Sea Drilling Project Leg 92) are (i) that sea-floor hydrothermal activity may fluctuate through time by as much as an order of magnitude and (ii) that episodes of greatest hydrothermal flux correspond to times when ridge-transform plate boundaries are undergoing major changes in their configuration rather than to known times of increased spreading rate or volcanism. Evidence is presented here in support of the hypothesis that heightened hydrothermal activity induced by the Eocene tectonic activity caused a global greenhouse effect, which may represent the long-sought-after historical analog to the carbon dioxide-induced global warming expected to occur by the middle of the next century.
Climate and Smoke: an Appraisal of Nuclear Winter
Authors: Turco R. P. , Toon O. B. , Ackerman T. P. , Pollack J. B. , Sagan C.
Published: October 2006

The latest understanding of nuclear winter is reviewed. Considerable progress has been made in quantifying the production and injection of soot by large-scale fires, the regional and global atmospheric dispersion of the soot, and the resulting physical, environmental, and climatic perturbations. New information has been obtained from laboratory studies, field experiments, and numerical modeling on a variety of scales (plume, mesoscale, and global). For the most likely soot injections from a full-scale nuclear exchange, three-dimensional climate simulations yield midsummer land temperature decreases that average 10° to 20°C in northern mid-latitudes, with local cooling as large as 35°C, and subfreezing summer temperatures in some regions. Anomalous atmospheric circulations caused by solar heating of soot is found to stabilize the upper atmosphere against overturning, thus increasing the soot lifetime, and to accelerate interhemispheric transport, leading to persistent effects in the Southern Hemisphere. Serious new environmental problems associated with soot injection have been identified, including disruption of monsoon precipitation and severe depletion of the stratospheric ozone layer in the Northern Hemisphere. The basic physics of nuclear winter has been reaffirmed through several authoritative international technical assessments and numerous individual scientific investigations. Remaining areas of uncertainty and research priorities are discussed in view of the latest findings.
Solubilization of a Stereospecific Opiate-Macromolecular Complex from Rat Brain
Authors: Simon Eric J. , Hiller Jacob M. , Edelman Irit
Published: October 2006

A [
3
H]etorphine-macromolecular complex has been solubilized from rat brain synaptosomal fraction by extraction with the nonionic detergent Brij 36T. Stereospecificity of binding to this solubilized complex was demonstrated by the finding that radioactivity in the complex was virtually eliminated when binding had occurred in the presence of excess levorphanol, an active narcotic analgesic, while it was unaffected by its inactive enantiomorph dextrorphan. Bound radioactivity was dissociated by proteolytic enzymes, sulfhydryl reagents, and heat, suggesting the presence of protein. The bound solubilized macromolecular moiety may be the opiate receptor.
Neutron Diffraction Analysis of Myoglobin: Structure of the Carbon Monoxide Derivative
Authors: Norvell John C. , Nunes Anthony C. , Schoenborn Benno P.
Published: October 2006

The locations of hydrogen and deuterium atoms and water molecules have been investigated in carbon monoxide myoglobin using neutron diffraction, and the results are compared with earlier work on metmyoglobin. Parallel real space refinements on the two molecules show relatively few changes, but do show the carbon monoxide molecule with the iron atom moving into the heme plane.
Neuroplasticity in the Sparing or Deterioration of Function After Early Olfactory Tract Lesions
Authors: Devor Marshall
Published: October 2006

Mating behavior in male hamsters depends on the sense of smell. Thus, complete transection of the lateral olfactory tract in adults eliminates mating. If the cut is made early in life, however, mating is spared. Partial section of the tract in adults does not affect mating, but similar cuts in the neonate lead to impaired mating performance later in life. Observed postsurgical rearrangements in the connections of axons in the lateral olfactory tract may explain both the sparing and the deterioration of function.
Orientation of Water in Striated Frog Muscle
Authors: Fung B. M.
Published: October 2006

Proton and deuterium nuclear magnetic resonance spectra of striated frog gastrocnemius muscle exhibit angular dependence, indicating partial orientation of water in the muscle. Nonzero static dipolar and quadrupolar interactions resulting from the anisotropic motion of the water molecules modulate the spin echo decays, contributing to their nonexponential behavior.
Retention of Nonhelical Procollagen Containing
cis
-Hydroxyproline in Rough Endoplasmic Reticulum
Authors: Uitto Jouni , Hoffman Hans-Peter , Prockop Darwin J.
Published: October 2006

Fibroblasts freshly isolated from embryonic tendons were incubated with a proline analog,
cis
-4-hydroxy-L-proline, which is incorporated into protein and which leads to the intracellular accumulation of nonhelical procollagen. Evidence is presented here that the nonhelical procollagen containing the analog is retained within the rough endoplasmic reticulum and does not pass to the smooth endoplasmic reticulum or Golgi vacuoles at a normal rate.
Strontium-90 in Man
Authors: Kulp J. Laurence , Eckelmann Walter R. , Schulert Arthur R.
Published: October 2006

The world-wide average strontium-90 content of man was about 0.12 micromicrocurie per gram of calcium (1/10,000 of the maximum permissible concentration) in the fall of 1955. A few values as high as 10 times the average have been obtained.

This value is in accord with the predicted value based on fallout measurements and fractionation through the soil-plant-milk-human chain.

With the present burden of strontium-90, this average level should rise to 1 to 2 micromicrocuries of strontium-90 per gram of calcium by 1970.
Monoamine Oxidase Activity Decreased in Cells Lacking Hypoxanthine Phosphoribosyltransferase Activity
Authors: Breakefield Xandra O. , Castiglione Carmela M. , Edelstein Susan B.
Published: October 2006

The Lesch-Nyhan syndrome in humans is characterized by lack of hypoxanthine phosphoribosyltransferase activity and neurologic abnormalities that suggest changes in catecholamine metabolism. Monoamine oxidase, which degrades biogenic amines, has decreased activity in noradrenergic murine neuroblastoma cell lines lacking hypoxanthine phosphoribosyltransferase activity and in skin fibroblasts from patients with the Lesch-Nyhan syndrome.
Residual Learning Deficit After Heavy Exposure to Cannabis or Alcohol in Rats
Authors: Fehr Kevin A. , Kalant Harold , LeBlanc A. Eugene
Published: October 2006

Acute oral administration of cannabis extract to rats (tetrahydrocannabinol dose, 10 milligrams per kilogram) impaired maze learning. The impairment was more marked after ten daily doses of the same size. After 1, 2, or 3 months' pretreatment with the same daily dose, followed by a 25-day drug-free period, no residual learning impairment was found. However, 6 months of daily administration of cannabis (tetrahydrocannabinol, 20 milligrams per kilogram) or alcohol (6 grams per kilogram) produced significant residual impairment of learning of maze and motor coordination tasks, 2 months or more after the last drug administration.
Hypothalamic Lesions and Sexual Behavior in the Female Rat
Authors: Law Thomas , Meagher Walter
Published: October 2006

This study reports selective effects on the mating pattern of the female rat of partial destruction of the hypothalamus. Independent neural control of the ovarian cycle and of the mating response are demonstrated. Both depressed and augmented female sexual activity are reported.
Oxygen Isotope Fractionation in Reactions Catalyzed by Enzymes
Authors: Feldman Daniel E. , Yost Henry T. , Benson Bruce B.
Published: October 2006

A study has been made of some of the enzymatic mechanisms responsible for the previously reported fractionation of oxygen isotopes by whole organisms. The data indicate that the fractionation occurs through the activity of metalloenzymes.
Changes in the Pattern of Nitrogen Excretion during the Life Cycle of the Newt
Authors: Nash Gerald , Fankhauser G.
Published: October 2006

In the course of its life cycle the eastern newt, Triturus (
Diemyctylus
)
viridescens
, undergoes two metamorphoses, the first from the aquatic larva to the terrestrial red eft; the second, 2 to 3 years later, from the eft to the permanently aquatic and sexually mature adult newt. The pattern of nitrogen exretion changes during both transformations. Older larvae excrete about 75 percent of the nitrogen as ammonia, 25 percent as urea; during the first metamorphosis the ratio of ammonia to urea is about 57:43; completely transformed efts excrete 87 percent of the nitrogen as urea. Adult aquatic newts show a partial return to the larval pattern, with an increase in the proportion of ammonia from the 13 percent typical for the eft to 26 percent, a highly significant difference.
Effect of Kinetin on Formation of Red Pigment in Seedlings of
Amaranthus retroflexus
Authors: Bamberger E. , Mayer A. M.
Published: October 2006

Kinetin induces formation of red pigment in seedlings of
Amaranthus retroflexus
in the dark. This effect is similar to the light-induced formation of pigment. Light and kinetin do not act in a simple additive way. The pigment is not an anthocyanin, and its formation is not affected by inhibitors of anthocyanin formation.
Cytochemical Adenosine Triphosphatase of Vorticellid Myonemes
Authors: Levine Laurence
Published: October 2006

A highly specific adenosine triphosphatase has been found to be localized in the contractile apparatus of vorticellids. It is most prominent in the cilia as well as in the myonemes which course the latitudes and longitudes of the cell and spiral in the flat peristome. The stalk displays more activity in the spasmoneme sheath than in the spasmoneme itself. The spasmoneme canal appears negative. A delicate fiber coils around the outside of the stalk in a helix. All these structures may be seen in the living protozoan by phasecontrast microscopy.
Low Temperature Induced Male Sterility in Male-Fertile
Pennisetum clandestinum
Authors: Youngner Victor B.
Published: October 2006

Controlled environment studies of
Pennisetum clandestinum
showed that at 10°C stamens of the male-fertile strain were not exserted from the floret although stigmas emerged normally. At higher temperatures both stamens and stigmas were exserted. Pollen abortion was high at 10°C and was increased by lengthening photoperiod. Flowering of the male-sterile strain was not changed by any temperature or photoperiod. These responses to temperature may explain the natural sterility during the cool season.
Ionium-Thorium Chronology of Deep-Sea Sediments of the Western North Pacific Ocean
Authors: Miyake Yasuo , Sugimura Yukio
Published: October 2006

The rate of deposition of deep-sea deposits collected at the depths of 6215 to 8450 m in the western part of the North Pacific Ocean was estimated by means of the ionium/thorium ratio. The ratio was determined by an alpha-ray spectrometer. Results showed the rate of 0.5 to 0.8 mm/10
3
yr for the upper 10-cm layer below the sea bottom.
Cytogenic Behavior of a Knobbed Chromosome 10 in Maize
Authors: Kikudome Gary Y.
Published: October 2006

Unlike maize plants heterozygous for the abnormal chromosome 10 (K10) and the normal chromosome 10 (k10), those heterozygous for a knobbed chromosome 10 (K
T
10/k10) do not undergo preferential segregation or "meiotic drive." Ting's chromosome 10, however, does show neocentric activity, although the extent of this is not as pronounced as is the case in K10 homozygotes. The K
T
10 chromosome is considerably shorter than and is cytologically distinguishable from the K10 and the k10 chromosomes.
Ocular Lesions Produced by an Optical Maser (Laser)
Authors: Zaret Milton M. , Breinin Goodwin M. , Schmidt Herbert , Ripps Harris , Siegel Irwin M. , Solon Leonard R.
Published: October 2006

Ocular lesions have been experimentally produced in rabbit by a pulsed optical maser (laser). The high-energy density delivered in a single 0.5 msec pulse was sufficient to cause instantaneous thermal injury to the pigmented retina and iris of the brown rabbit. Ophthalmoscopically, the retinal lesions resembled flash burns from an atomic fireball.
Dopamine-Sensitive Adenylate Cyclase: Location in Substantia Nigra
Authors: Gale K. , Guidotti A. , Costa E.
Published: October 2006

A dopamine-sensitive adenylate cyclase with characteristics similar to those measured in the striatum is present in the rat substantia nigra. Destruction of dopamine cell bodies by intranigral 6-hydroxydopamine application failed to abolish the response of nigral adenylate cyclase to dopamine. In contrast, brain hemitransection between the striatum and substantia nigra, or a more circumscribed lesion of striatonigral pathways, abolished the dopamine stimulation of adenylate cyclase in the substantia nigra. These results suggest that dopamine receptors within the substantia nigra are not located on dopamine cell bodies but are associated with a pathway, containing γ-aminobutyric acid or substance P, which projects from forebrain structures to the substantia nigra.
Quantum Efficiency of Cytochrome Oxidation in a Photosynthetic Bacterium
Authors: Olson John M.
Published: October 2006

Illumination of
Chromatium
with light absorbed by bacteriochlorophyll causes the oxidation of intracellular cytochrome. The quantum efficiency of this reaction approaches one electron per photon at 589 millimicrons and at wavelengths between 862 and 908 millimicrons. The efficiency of converting excitation energy to chemical energy is estimated to be about 30 percent.
Simazine: Degradation by Corn Seedlings
Authors: Hamilton Robert H. , Moreland Donald E.
Published: October 2006

The herbicide 2-chloro-4,6-bis(ethylamino)-
s
-triazine (simazine) is converted to 2-hydroxy-4,6-bis(ethylamino)-
s
-triazine (hydroxysimazine) in vivo by corn seedlings and in vitro by corn extracts. Hydroxysimazine is considered to be a detoxified form of the herbicide. In vitro conversion was produced by reacting simazine with either a cyclic hydroxamate (2,4-dihydroxy-3-keto-7-methoxy-1,4-benzoxazine) or its glucoside. The latter compounds may mediate at least some of the in vivo conversion in corn.
Chemical Regulation of Flower Sex Expression and Vegetative Growth in
Cucumis sativus
L.
Authors: Mitchell Wm. D. , Wittwer S. H.
Published: October 2006

Pistillate flower formation in monoecious cucumber plants is increased when allyl trimethylammonium bromide is added to aerated solution cultures used as the root medium. By contrast, gibberellin induces staminate flower formation on gynoecious cucumber plants. The two chemicals also have diametrically opposite effects in tendril formation and vegetative extension.
Structure of Nuclei and Nucleons
Authors: Hofstadter R.
Published: October 2006

In concluding this discussion it may be appropriate to return to the theme introduced earlier and raise the question once again of the deeper, and possibly philosophical, meaning of the term "elementary" particle. As we have seen, the proton and neutron, which were once thought to be elementary particles, are now seen to be highly complex bodies. It is almost certain that physicists will subsequently investigate the constituent parts of the proton and neutron—the mesons of one sort or another. What will happen from that point on? One can only guess at future problems and future progress, but my personal conviction is that the search for ever-smaller and ever-more-fundamental particles will go on as long as man retains the curiosity he has always demonstrated.
High-Speed Microcinematographic Studies of Blood Flow in vitro
Authors: Bugliarello George , Hayden John W.
Published: October 2006

The macroscopically steady flow of human blood at varying hematocrit values and flow rates through small glass capillaries has been studied by following in detail the motion of individual erythrocytes. At the microscopic level the flow was found to be nonuniform and unsteady. The shape of the average velocity profile of the erythrocytes was found to be in general more blunt than the Newtonian profile, and to be affected by concentration and flow rate, particularly in the capillaries of smaller diameter.
Cell Guidance by Alterations in Monomolecular Films
Authors: Rosenberg Murray D.
Published: October 2006

Monolayers of stearic and behenic acids were transferred to quartz slides by the Blodgett technique. Troughs of different depths were cut into these multilayers (substrata), and additional monolayers were superimposed. When cultured and fresh embryonic cells were grown on these substrata, the cells were entrapped within troughs whose depths were as small as 60 angstroms. The results demonstrate cellular responses to molecular changes in contact surfaces.
Intracellular Potentials of Cortical Neurons during Focal Epileptogenic Discharges
Authors: Goldensohn Eli S. , Purpura Dominick P.
Published: October 2006

Focal electroencephalographic discharges in lesions of cortex induced by freezing are associated with prolonged membrane depolarizations and hyperpolarizations in neurons located at various depths in the lesion sites. Transmembrane potential changes have properties similar to those of postsynaptic potentials. The temporal relationship between intracellular potentials and paroxysmal discharges indicates that the latter are extracellularly recorded summations of synchronously developing depolarizations and hyperpolarizations in complex synaptic organizations of neurons.
Hazards of New Drugs
Authors: Modell Walter
Published: October 2006

Oliver Wendell Holmes said 100 years ago, "I firmly believe that if the whole materia medica as now used could be sunk to the bottom of the sea, it would be all the better for mankind—and all the worse for the fishes." This is still true for the fishes; in fact, with our more potent drugs, it would be even worse for them. So far as mankind is concerned, however, I disagree; I need point only to our vastly improved mortality and morbidity rates. But mankind would be still better off if the physician treated the products of modern science with due regard for the principles of science; if there were no pressures distracting him from these principles; and if, in attacking disease, he viewed the large problem, with its long-range implications, as well as the immediate effects on a number of dissociated diseases. I think that the physician must transcend the businessman's ethic, and also that the safe and effective clinical use of new drugs requires a new and acceptable image of the physician, one which combines the qualities of Dr. Christian and the discipline and special skill and logic of the scientist.
Retention in Immediate Memory Estimated without Retrieval
Authors: Buschke Herman
Published: October 2006

Report of the missing member of a set depends upon retention of the other members presented. Such a missing scan reveals greater retention than does a digit span and, unlike the digit span, better retention of later than earlier presentations.
X-Ray Sensitivity and DNA Synthesis in Synchronous Populations of HeLa Cells
Authors: Terasima Toyozo , Tolmach L. J.
Published: October 2006

Inhibition with either 5-fluorodeoxyuridine or deoxyadenosine for specified periods during the division cycle of the HeLa S3 cell shows that the mid-interphase peak in sensitivity occurs just before DNA replication begins. Sensitivity subsequently decreases only after synthesis of DNA is resumed. One interpretation of the relation between fluctuations in sensitivity and in DNA synthesis is that the lethal radiation damage to these cells occurs in DNA.
Enzymatic Formation of Adrenaline and Other Catechols from Monophenols
Authors: Axelrod Julius
Published: October 2006

An enzyme that forms adrenaline from
p
- and
m
-sympathol and dopamine from
p
- and
m
-tyramine is localized in the microsomes of rabbit liver and requires the reduced form of nicotinamide adenine dinucleotide phosphate. The enzyme is nonspecific and can form catechols from the following normally occurring and foreign phenols:
p
- and
m
-octopamine,
p
-hydroxyephedrine, phenol, stilbestrol,
N
- acetyl-
p
-aminophenol, estradiol and
N
- acetylserotonin.
Somatic Inheritance of Habituation of Responses to Light in Planarians
Authors: Westerman R. A.
Published: October 2006

Planarians show long-lasting reversible decrease of responses to a photic stimulus repeated 25 times each day. This habituation was found to be significantly faster in regenerated offspring of previously habituated planarians, and was also transferred by cannibalization, thus resembling light-shock conditioning. Habituation provides a new situation in which to study the somatic inheritance of learning in planarians.
Xenon Fluorides: Fluorine-19 Nuclear Magnetic Resonance Spectra
Authors: Rutenberg A. C.
Published: October 2006

Chemical shifts have been measured for liquid XeF
2
, XeF
4
, XeOF
4
, and XeF
6
, and F
19
-Xe
129
spin-spin coupling constants for XeF
4
and XeOF
4
. The data are in accord with reported structures and are similar to values in the literature for chemical shifts of fluorides of neighboring elements.
Tobacco Mosaic Virus: Purifying and Sorting Associated Particles According to Length
Authors: Steere Russell L.
Published: October 2006

End-to-end aggregation of tobacco mosaic virus and associated particles during extraction and purification may be prevented by transfer of the virus to 0.001M buffer solution of ethylenediaminetetraacetic acid,
p
H 7.5, as rapidly as practicable. Colored components were removed with charcoal and diatomaceous earth, and salts by rapid passage through a column of granulated 8 percent agar gel. The virus particles were sorted according to length by passage through a 1 percent granulated agar-gel column to isolate the 300- and 200-mμ fractions and through a 5 percent agar gel to isolate the shorter particles.
Organized Element: Possible Identification in Orgueil Meteorite
Authors: Fitch Frank W. , Anders Edward
Published: October 2006

Ragweed pollen stained by the Gridley method becomes distorted so that it resembles Claus and Nagy's Type 5 organized element, a particle found in a Gridley-stained preparation of the Orgueil carbonaceous chondrite.
Thyroxine: Effects on Amino Acid Incorporation into Protein in vivo
Authors: Michels Robert , Cason John , Sokoloff Louis
Published: October 2006

Treatment of rats with L-thyroxine increases the incorporation in vivo of radioactive amino acids into protein of liver, kidney, and heart, but not of spleen, testis, or brain. The distribution of the effect among the organs is the same as that observed in thyroxine stimulation of oxidative metabolism. Thus, stimulation of protein synthesis seems to be a physiological action of the thyroid hormone.
Photochemical Generation of the Hydrated Electron
Authors: Grossweiner Leonard I. , Swenson George W. , Zwicker Earl F.
Published: October 2006

A transient species with properties similar to the hydrated electron produced previously by electron irradiation has been observed by flash photolysis of aqueous solutions of inorganic salts and aromatic compounds including amino acids.
Ion-Exchange Removal of Sodium Chloride from Water with Calcium Hydroxide as Recoverable Regenerant
Authors: Popper Karel , Bouthilet Robert J. , Slamecka Vladimir
Published: October 2006

A mixture of cation- and anion-exchange resins, in proportions corresponding to their particular exchange properties and charged with calcium hydroxide, removes seawater salts from solution exchanging calcium hydroxide for the sodium chloride. The regenerant is recoverable. A portion of it may be used again without handling.
Chlorine Pentafluoride
Authors: Smith D. F.
Published: October 2006

The bonding in the halogen polyfluorides is similar to that in the xenon fluorides. Since XeF
4
exists, the previously unreported ClF
5
should exist. This compound has been prepared by heating ClF
3
in the presence of fluorine at high pressure. Chlorine pentafluoride is a square pyramidal molecule. It has a lower melting point than ClF
3
and a higher vapor pressure. It is also less reactive than ClF
3
.
X-ray Diffraction Studies on Tin at High Pressure and High Temperature
Authors: Barnett J. Dean , Bennion Roy B. , Hall H. Tracy
Published: October 2006

Tin at a pressure of 39 kb and at 314°C has tetragonal symmetry with an atom at each point of a body-centered tetragonal lattice. The unit cell dimensions are
a
equal to 3.81 Å,
c
equal to 3.48 Å, and
c
/
a
= 0.91. The melting curve of tin was observed up to 45 kb and the boundary line between the tin I and tin II phases was observed to 70 kb by x-ray diffraction techniques.
Streptomycin as an Antiviral Agent: Mode of Action
Authors: Brock Thomas D. , Wooley Susan O.
Published: October 2006

In host bacteria resistant to the antibiotic, streptomycin inhibits phage replication by inhibiting the process of injection. This effect is competitively reversed by certain divalent cations, polyamines, and streptidine. It is proposed that streptomycin inhibits injection by attaching to the phage DNA while it is still folded within the phage head, and in this way it prevents the unfolding which is essential for the injection process. The reversal agents probably function by displacing the antibiotic from the phage, but they also promote injection themselves.
Exponential Values for the Species-Area Relation
Authors: Kilburn Paul D.
Published: October 2006

Data on vegetation types in six 900-m
2
plots in the Midwest reveal that the species-area curves are not logarithmic but more nearly approach an exponential equation of the form y = kx
2
for areas less than 100 m
2
. For larger areas the curve appears to be sigmoid.
Slowing of Mortality Rates at Older Ages in Large Medfly Cohorts
Authors: Carey James R. , Liedo Pablo , Orozco Dina , Vaupel James W.
Published: October 2006

It is generally assumed for most species that mortality rates increase monotonically at advanced ages. Mortality rates were found to level off and decrease at older ages in a population of 1.2 million medflies maintained in cages of 7,200 and in a group of approximately 48,000 adults maintained in solitary confinement. Thus, life expectancy in older individuals increased rather than decreased with age. These results cast doubt on several central concepts in gerontology and the biology of aging: (i) that senescence can be characterized by an increase in age-specific mortality, (ii) that the basic pattern of mortality in nearly all species follows the same unitary pattern at older ages, and (iii) that species have absolute life-span limits.
Electrophysiologic Indications of the Osmoregulatory Role of the Teleost Urophysis
Authors: Yagi Kinji , Bern Howard A.
Published: October 2006

Tilapia mossambica
when placed in salt water shows an increase in the frequency of spontaneous discharges in some neurosecretory fibers in the urophysis of the caudal neurosecretory system. Exposure to tap water usually depresses this activity. The nature of the ion-regulatory action of the caudal neurosecretory system of teleosts remains conjectural, but the data currently available indicate the possible production of two kinds of neurohormones, one which favors ion movement in the normal direction and another which has the opposite effect in response to abnormal osmotic circumstances.
Process of Infection with ϕX174: Effect of Exonucleases on the Replicative Form
Authors: Burton Alice , Sinsheimer Robert L.
Published: October 2006

When a preparation containing the DNA of the bacteriophage φX174 in its replicative form together with DNA from
Escherichia coli
is treated with exonucleases, the replicative form retains its characteristic physical properties, while the bacterial DNA is degraded. The evidence suggests that the mature replicative form exists as a closed ring.
Conglutination: Specific Inhibition by Carbohydrates
Authors: Leon Myron A. , Yokohari Ryuichi
Published: October 2006

Conglutination of antigen-antibody-complement complexes is inhibited by a number of acetamido sugars, the most efficient being
N
-acetyl-D-glucosamine and closely related compounds. The effects of structural modification on activity of
N
-acetyl-D-glucosamine are described.
Mössbauer Effect for Surface Atoms: Iron-57 at the Surface of η Al
2
O
3
Authors: Flinn P. A. , Ruby S. L. , Kehl W. L.
Published: October 2006

The Mössbauer effect has been observed for Fe
57
atoms at the surface of η Al
2
O
3
. The Fe
57
is trivalent, and the quadrupole splitting found is consistent with a surface location. Anisotropy of thermal vibration relative to the surface is observed.
In Vitro Transcriptional Activation by a Metabolic Intermediate: Activation by Leu3 Depends on α-Isopropylmalate
Authors: Sze Ji-Ying , Woontner Michael , Jaehning Judith A. , Kohlhaw Gunter B.
Published: October 2006

In the absence of the leucine biosynthetic precursor α-isopropylmalate (α-IPM), the yeast LEU3 protein (Leu3p) binds DNA and acts as a transcriptional repressor in an in vitro extract. Addition of α-IPM resulted in a dramatic increase in Leu3p-dependent transcription. The presence of α-IPM was also required for Leu3p to compete effectively with another transcriptional activator, GAL4/VP16, for limiting transcription factors. Therefore, the addition of α-IPM appears to convert a transcriptional repressor into an activator. This represents an example in eukaryotes of direct transcriptional regulation by a small effector molecule.
Urea: Apparent Carrier-Mediated Transport by Facilitated Diffusion in Dogfish Erythrocytes
Authors: Murdaugh H. Victor , Robin Eugene D. , Hearn Claude D.
Published: October 2006

The exposure of erythrocytes from the elasmobranch,
Squalus acanthias
, to solutions isosmotic with plasma (1
M
) but containing urea or hydroxyurea as the sole solute does not produce hemolysis. Exposure of these cells to 1
M
methylurea, thiourea and acetamide does produce hemolysis. Low concentrations of urea, which are associated with hemolysis, protect dogfish red cells against hemolysis by methylurea and thiourea. Dogfish red cells exposed to mediums containing high concentrations of urea, or no urea, reach 95 percent of their equilibrium concentration in less than 5 minutes.
Radioactivity in the Atmospheric Effluents of Power Plants That Use Fossil Fuels
Authors: Eisenbud Merril , Petrow Henry G.
Published: October 2006

Analysis of the fly ash produced by combustion of pulverized Appalachian coal has shown that a 1000-megawatt coal-burning power plant will discharge into the atmosphere from about 28 millicuries to nearly 1 curie per year of radium-226 and radium-228. An oil-burning plant of similar size will discharge about 0.5 millicurie of radium per year. Comparison of these data with data on the release of fission products from nuclear-powered generating stations shows that when the physical and biological properties of the various radionuclides are taken into consideration, the conventional fossil-fueled plants discharge relatively greater quantities of radioactive materials into the atmosphere than nuclear-powered plants of comparable size.
Xenon Hexafluoride Complexes
Authors: Selig Henry
Published: October 2006

Xenon hexafluoride reacts with BF
3
and AsF
5
to form 1:1 adducts which are white solids with vapor pressures of less than 1 millimeter at room temperature. The XeF
6
⋅ BF
3
adduct melts at 90°C to a pale yellow viscous liquid.
Affinity and Phosphorylation Constants for the Inhibition of Esterases by Organophosphates
Authors: Main A. R.
Published: October 2006

Equations based on the assumption of a reversible first step in the reaction between organophosphate inhibitors and esterases are proposed for the bimolecular rate constant which now includes an affinity constant and a phosphorylation constant. The treatment applies when the inhibition reaction follows first-order kinetics.
Mitotically Synchronized Mammalian Cells: A Simple Method for Obtaining Large Populations
Authors: Robbins Elliott , Marcus Philip I.
Published: October 2006

Eliminating most of the ionic calcium from growth medium does not affect cell growth, but it allows simple and preferential detachment of HeLa cells in mitosis from nearly confluent monolayers.
Nucleic Acids: A Nuclear Magnetic Resonance Study
Authors: McDonald C. C. , Phillips W. D. , Penman Sheldon
Published: October 2006

Single-stranded nucleic acids in aqueous media exhibit proton magnetic resonance spectra with acceptable signal-noise ratios if multiple scans of the spectra are stored in and subsequently read out of a computer of average transients. Partial ordering of the adenine bases of polyadenylic acid in solution is reflected in contributions to the chemical shifts that are removed on "melting." More significantly, secondary structure such as occurs in complexes of polyA and polyU and in double-stranded DNA is manifested in proton magnetic resonance spectra below the "melting" temperature by severe resonance line broadening which results from anisotropic nuclear dipole-dipole interactions. The proton resonances are narrowed in and above the "melting" region, and measurement of integrated resonance intensities can give insight into quantitative aspects of hybridization, "melting," and other nucleic acid interactions.
Geological Aspects of High-Pressure Research
Authors: Boyd F. R.
Published: October 2006

The low-density minerals that make up the bulk of rocks in the earth's crust, such as quartz and the feldspars, are transformed by high pressure into much denser phases. In some cases the products of these transitions are new phases that were first discovered in the laboratory; in other cases they are minerals such as kyanite, jadeite, and pyrope, which have long been known as constituents of metamorphic rocks. Determinations of the stability fields of these high-pressure minerals show that either metamorphism of sedimentary rocks takes place at much greater depth than has hitherto been supposed or pressures generated by orogenic forces may have significantly augmented the hydrostatic pressure. The second alternative seems unlikely, but lack of information on the strength of rocks during metamorphism makes the matter uncertain.

Geophysical and petrological observations indicate that the dominant rock type in the upper mantle is garnet peridotite. However, there is reason to believe that the mantle is inhomogeneous and that a variety of rocks ranging in bulk composition from eclogite to peridotite are present. Hydrous phases, such as amphiboles, are possible constituents in the upper 100 kilometers. The hypothesis that the Mohorovičić discontinuity is a dynamic equilibrium between basalt and eclogite seems improbable.

The transition zone between the upper and lower mantle can be explained as a series of reactions in which silicates with the silicon ion in fourfold coordination are transformed into phases in which silicon is in six-fold coordination. This interpretation is supported by synthesis of stishovite, a polymorph of SiO
2
with rutile structure, and by syntheses of germanate pyroxenes with ilmenite structure.

Data on the melting of silicates at pressures up to 50 kilobars show that the initial d
T
/d
P
slopes of silicate melting curves are much steeper than those of metals but that they show considerable curvature. The increase of melting temperature with pressure should be much more pronounced near the top of the mantle than at greater depth.
Tetracycline Fluorescence in Permeability Studies of Membranes around Intracellular Parasites
Authors: du Buy H. G. , Riley F. , Showacre J. L.
Published: October 2006

Certain protozoa, bacteria, and viruses when phagocytosed by host cells become surrounded by an intracytoplasmic boundary. This membrane prevents the fluorescent antibiotic tetracycline from entering the parasites when it is added to the medium, since they show no fluorescence, whereas extracellular parasites are immediately visible. As soon as the host cell dies, the intracellular parasites also become visible. This indicates that the boundary probably is of host origin. This phenomenon provides a means for selective permeability studies of such boundaries. A similar exclusion of tetracycline from certain extracellular parasites is seen in the presence of whole serum.
A Primitive Heart in the Echinoid
Strongylocentrotus purpuratus
Authors: Boolootian Richard A. , Campbell James L.
Published: October 2006

A pulsating vessel and a compartmented contractile chamber have been found to move coelomic fluid from the perivisceral cavity into and throughout the hemal system of the sea urchin,
Strongylocentrotus purpuratus
.
Hypertensive Vascular Disease Produced by Homologous Renin
Authors: Masson Georges M. C. , Kashii Chujiro , Matsunaga Masato , Page Irvine H.
Published: October 2006

Administration of rat renin to uninephrectomized rats reproduced most, if not all, the changes (hypertension, vascular disease, hypertrophy of the zona glomerulosa of the adrenals) found after partial constriction of the renal artery. This is taken as evidence that the renal pressor system plays a major role in the pathogenesis of renal hypertension.
Vitamin K Induced Prothrombin Formation: Antagonism by Actinomycin D
Authors: Olson Robert E.
Published: October 2006

Actinomycin D inhibits vitamin K induced formation of prothrombin in chicks deficient in vitamin K. The administration of actinomycin in doses which inhibit prothrombin formation also inhibits synthesis in the liver of RNA from adenosine triphosphate as detected with adenine-8-C
14
. The results are consistent with a genetic action of vitamin K in inducing RNA formation for the synthesis of clotting proteins.
Mechanoreceptors in the Cuticle of the Honey Bee: Fine Structure and Stimulus Mechanism
Authors: Thurm Ulrich
Published: October 2006

The distal nerve process of hair plate sensilla and campaniform sensilla contains a special terminal structure in the form of a bundle of tubules herein designated the "tubular body." Physiological and morphological results indicate that compression at the site of this body probably acts as the stimulus at the cellular level. A ciliary structure separates an outer segment of the distal nerve process from the remaining distal fiber.
Sensitivity of Visual Receptors of Carotenoid-Depleted Flies: A Vitamin A Deficiency in an Invertebrate
Authors: Goldsmith Timothy H. , Barker Roy J. , Cohen Charles F.
Published: October 2006

House flies (
Musca domestica
) raised under sterile conditions on a diet lacking carotenoids and retinol (vitamin A) have visual receptor sensitivities—as assessed electroretinographically—which average more than 2 log units below normal, both in the near ultraviolet (340 mμ) and visible (500 mμ) regions of the spectrum. Loss of sensitivity can be prevented by the addition of β-carotene to the larval food. Flies reared for several generations on a carotenoid-free diet, but under conditions where the adults are not kept sterile, do not show a further loss of sensitivity. It is suggested that carotenoid stored in the egg prevents complete blindness in the first generation, and that microorganisms can supply small amounts of carotenoid and thereby prevent complete blindness in the second and successive generations.
Pressure-Induced Trapping Phenomenon in Silver Iodide
Authors: Duecker H. C. , Lippincott Ellis R.
Published: October 2006

Observations of the optical properties and electrical conductivity of silver iodide at pressures between 2 and 4 kilobars are indicative of the formation of free silver (or silver and iodine) in this pressure range. On the basis of the sequence of events and the volume relations, this reaction could account for the smooth and reversible phase transformations of silver iodide in this pressure range. The phenomenon may be due to the trapping of an electron by the silver ion (in a thermally excited state) as a result of the distortion of the lattice under pressure.
Spore Discharge in Basidiomycetes: A Unified Theory
Authors: Savile D. B. O.
Published: October 2006

Olive's demonstration that a bubble bursting at the basidiospore apiculus breaks the connection between spore and sterigma convincingly explains the mechanism of severance; but it does not explain spore discharge, because the bursting force is not applied in the appropriate direction. The form of the developing spore and sterigma shows that the spore is forcibly abstricted while the membrane is still fluid. If the abstricting force persists until the fracture of the sterigma, it provides a mechanism whereby the spore is reliably discharged.
Drug Antagonism between Lincomycin and Erythromycin
Authors: Griffith L. J. , Ostrander W. E. , Mullins C. G. , Beswick D. E.
Published: October 2006

An antagonistic action can be demonstrated between lincomycin, a new antibiotic, and erythromycin, when the two drugs are allowed to diffuse into the same area of an agar plate seeded with a strain of
Staphylococcus
which is resistant to erythromycin but sensitive to lincomycin. The increase in the minimum inhibitory concentrations of lincomycin in the presence of erythromycin may be significant in clinical application. The antagonism does not depend on a reaction between the two antibiotics, but appears to be the result of an altered metabolism stimulated by erythromycin on erythromycin-resistant staphylococci.
Crystallization and Molecular Folding
Authors: Lindenmeyer P. H.
Published: October 2006

The long-chain nature of the polymer molecule, together with the usual broad distribution of molecular lengths, makes it kinetically very unlikely that the molecule will achieve, on crystallization, its thermodynamically most stable form. Under most crystallization conditions a large portion of the polymer molecules crystallize into folded-chain crystals. Only a small fraction of the molecules of lower molecular weight, initially rejected from the growing folded-chain crystals, succeed in achieving the stable, fractionated, extended-chain crystalline form. The physical properties of the resulting polycrystalline structure are very strongly dependent upon the amount and kind of molecular folding which has occurred. In general, folded-chain crystals are tough and ductile and tend to produce low modulus and high elongation, whereas extended-chain crystals are brittle and tend to have higher modulus.
Sweating: Direct Influence of Skin Temperature
Authors: van Beaumont W. , Bullard Robert W.
Published: October 2006

The onset and magnitude of the sweating response is greatly influenced by the local skin temperature. This influence was evident with skin temperatures above 33°C and occurred in the physiological range for thermo-regulatory sweating. The sweating rates were recorded continuously and simultaneously from three areas of the skin.
Electron Spin Resonance of Irradiated DNA
Authors: Pershan P. S. , Shulman R. G. , Wyluda B. J. , Eisinger J.
Published: October 2006

When DNA is irradiated by ultraviolet light a paramagnetic damage center is formed in the thymine bases. The structure of this free radical has been determined by electron spin resonance and consists of a hydrogen addition at the carbon No. 6 position. The rate of formation of the radical is enhanced by water vapor, and it is quenched by paramagnetic ions bound to the DNA.
Countercurrent Multipliers in Avian Kidneys
Authors: Poulson Thomas L.
Published: October 2006

The capacity to conserve urinary water by producing a concentrated urine is directly related to the number of Henle's loops in the kidneys of three terrestrial birds. This suggests that a Henle's loop countercurrent multiplier is responsible for urine concentration in these birds. Several features of the organization of the kidneys of these birds may account for the importance of multiplier number, as contrasted to multiplier length in mammals, in determining maximum urine concentration.
Potassium-40 Content as a Basis for the Calculation of Body Cell Mass in Man
Authors: Burmeister Walther
Published: October 2006

On the assumption that the potassium content of the body cell mass is constant it should be possible to estimate body cell mass by measuring potassium-40 activity with a whole-body scintillation counter. Relations of body cell mass to weight, lean body mass, and total body water are demonstrated.
Spermidine in Regenerating Liver: Relation to Rapid Synthesis of Ribonucleic Acid
Authors: Dykstra William G. , Herbst Edward J.
Published: October 2006

The spermidine in rat liver increases after partial hepatectomy, and the rate of polyamine accumulation closely approximates the increased rate of synthesis of RNA in regenerating liver. The uptake by the liver of intravenously injected putrescine and the biosynthesis of spermidine are accelerated within 2 hours after the operation. The uptake of spermidine also increases during early regeneration.
α-Hydroxy Acid Oxidase: Localization in Renal Microbodies
Authors: Allen John M. , Beard Margaret E.
Published: October 2006

Differential and density equilibrium centrifugation have established the presence of α-hydroxy acid oxidase in microbodies of the kidney of the rat. The enzyme has been demonstrated in cells of the distal convoluted tubule by a microscopic cytochemical method. This enzyme, like certain others in microbodies, produces hydrogen peroxide.