bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Models for the Metal Centers in the Nitrogenase Molybdenum-Iron Protein
Authors: Kim Jongsun , Rees D. C.
Published: October 2006

Structural models for the nitrogenase FeMo-cofactor and P-clusters are proposed based on crystallographic analysis of the nitrogenase molybdenum-iron (MoFe)-protein from
Azotobacter vinelandii
at 2.7 angstrom resolution. Each center consists of two bridged clusters; the FeMo-cofactor has 4Fe:3S and 1Mo:3Fe:3S clusters bridged by three non-protein ligands, and the P-clusters contain two 4Fe:4S clusters bridged by two cysteine thiol ligands. Six of the seven Fe sites in the FeMo-cofactor appear to have trigonal coordination geometry, including one ligand provided by a bridging group. The remaining Fe site has tetrahedral geometry and is liganded to the side chain of Cys
α275
. The Mo site exhibits approximate octahedral coordination geometry and is liganded by three sulfurs in the cofactor, two oxygens from homocitrate, and the imidazole side chain of His
α442
. The P-clusters are liganded by six cysteine thiol groups, two which bridge the two clusters, α88 and β95, and four which singly coordinate the remaining Fe sites, α62, α154, β70, and β153. The side chain of Ser
β188
may also coordinate one iron. The polypeptide folds of the homologous α and β subunits surrounding the P-clusters are approximately related by a twofold rotation that may be utilized in the binding interactions between the MoFe-protein and the nitrogenase Fe-protein. Neither the FeMo-cofactor nor the P-clusters are exposed to the surface, suggesting that substrate entry, electron transfer, and product release must involve a carefully regulated sequence of interactions between the MoFe-protein and Fe-protein of nitrogenase.
Chondrules: Suggestion Concerning the Origin
Authors: Whipple Fred L.
Published: October 2006

The millimeter-sized, sometimes glassy spheroids called chondrules that occur abundantly in stony meteorites may have been produced by lightning in the primitive Laplacian-type nebula while earthy materials were condensing and collecting to form the asteroids and the terrestrial planets.
Peroxidase and Resistance to
Ceratocystis
in Sweet Potato Increased by Volatile Materials
Authors: Clare Bruce , Weber Darrell J. , Stahmann Mark A.
Published: October 2006

Increased peroxidase activity and resistance to black rot was found in sweet potato roots incubated above infected roots in closed containers when compared with similar tissue incubated above uninfected roots. The peroxidase increases were detected in unpurified extracts and in extracts subjected to gel electrophoresis.
Kyanite-Andalusite Equilibrium from 700° to 800°C
Authors: Newton Robert C.
Published: October 2006

The metastable kyaniteandalusite equilibrium in the Al
2
SiO
5
system has been reversed at 700°, 750°, and 800°C at elevated water pressures, with a variety of natural and synthetic kyanites and andalusites as starting materials. Sillimanite, the stable form of Al
2
SiO
5
under these conditions, did not appear. The value of the transition pressure at 750°C is 6.6 ± 0.4 kilobars, several kilobars below pressures given by several convergent previous determinations. The Al
2
SiO
5
pressure-temperature triple point now indicated lies far from the points found by others. The revised aluminum silicate phase diagram indicates that many rocks crystallized at lower pressures than formerly thought possible.
Hypophyseal Control of Genetic Expression during Chick Feather and Skin Differentiation
Authors: Yatvin Milton B.
Published: October 2006

The normal sequence of molecular events which occurs during feather and skin differentiation in the chick embryo is interrupted by pituitary gland ablation. The characteristic pattern of development is reestablished in hypophysectomized embryos treated with pituitary extract and in hypophysectomized embryos in parabiotic union with their twins within a double-yolked egg. These results suggest that genetic expression in differentiating chick feather and skin after day 12 of incubation is regulated by hormones.
Mexican Freetail Bats: Photography
Authors: Edgerton Harold E. , Spangle Paul F. , Baker James K.
Published: October 2006

A method is described for photographing bats or other rapidly moving objects as they intercept in space a particular area which is covered by a camera system. Photographs taken at Carlsbad Caverns show that the tail membrane of the Mexican freetail bat is extended when the animal is in flight.
Electron-Microscopic Autoradiography of Rat Hypothalamus after Intraventricular H
3
-Norepinephrine
Authors: Aghajanian G. K. , Bloom F. E.
Published: October 2006

Tritiated norepinephrine was injected into the lateral ventricles of rats, and its localization in the hypothalamus was determined by light and electron-microscopic autoradiography. Eighty percent of the autoradiographic grains were located over nerve endings and unmyelinated axons. Large, dense synaptic vesicles were present in most of the endings and axons with activity. Grains were rarely seen over myelinated axons, glia, or blood vessels.
Fruit Storage at Subatmospheric Pressures
Authors: Burg Stanley P. , Burg Ellen A.
Published: October 2006

The storage life of bananas and other fruits is prolonged by ventilating them with air at less than atmospheric pressure. This procedure accelerates the escape of the ripening hormone ethylene from the tissue; by reducing the oxygen tension it also lowers the fruit's sensitivity to the hormone.
Genetic Code: Aspects of Organization
Authors: Goldberg Alfred L. , Wittes Robert E.
Published: October 2006

The pattern of organization of the genetic code decreases to a minimum the phenotypic effects of mutation and of base-pairing errors in protein synthesis. Single base changes, especially transitions, usually cause either no amino acid change or the change to a chemically similar amino acid. The degree of degeneracy of the codons for an amino acid is correlated with their guanine-cytosine content. The code gives greater protection (by both degeneracy and guaninecytosine content of codons) to those amino acids that appear more frequently in proteins. Increased reliability of the protein-synthesis system afforded by this pattern of organization may have determined the fitness of the present code.
Molokai Fracture Zone: Continuation West of the Hawaiian Ridge
Authors: Malahoff Alexander , Strange W. E. , Woollard G. P.
Published: October 2006

The Molokai Fracture Zone is one of the principal east-west (striking) fracture zones between California and the mid-Pacific. On the basis of bathymetry alone, it has been assumed that the zone ended abruptly east of the Hawaiian Islands. Use of correlation techniques between bathymetric features and their magnetic anomalies in the vicinity of the islands now show that structural elements of the zone cross the islands and continue westward for at least 130 kilometers. Recent volcanism and deep rift zones of the islands parallel the zone, suggesting structural correlation between the strike of the zone and the origin of recent volcanism in the islands.
Synthetic Detergents: Their Influence upon Iron-Binding Complexes of Natural Waters
Authors: Kent Fred , Hooper Frank F.
Published: October 2006

Organic compounds extracted from Michigan lakes and streams and added to algal cultures increase the growth rate of the green alga (
Chlamydomonas reinhardi
) when iron is present. Two-dimensional paper chromatography has shown that the iron is complexed by organic fractions containing an amine group. When isolated from natural waters containing a concentration of over 0.3 part per million alkyl benzene sulfonate, these compounds do not show an iron-binding capacity. Separation of this sulfonate from the amine complexes restores the iron-binding capability. These findings suggest that detergents may influence the mobility of iron by reducing the number of binding sites, and in this way may have an important secondary effect upon the primary production of lakes and streams.
Leucine Incorporation into the Membranellar Bands of Regenerating and Nonregenerating
Stentor
Authors: de Terra Noël
Published: October 2006

Autoradiographs of membranellar bands isolated from regenerating and nonregenerating stentors labeled with tritiated leucine indicate that the synthesis of proteins of the oral apparatus is continuous in Stentor and is not initiated at the time of regeneration.
Hepatic Synthesis of Alpha
2
(Acute Phase)-Globulin of Rat Plasma
Authors: Sarcione Edward J. , Bogden Arthur E.
Published: October 2006

Synthesis of plasma alpha
2
(acute phase)-globulin was demonstrated in isolated perfused rat liver obtained from animals showing acute inflammatory reaction to injury. These findings indicate that the liver is a source of the globulin and that appearance of this protein in the serum results from de novo synthesis by the liver rather than from release of performed and stored globulin.
Laboratory Culturing of a Thermophilic Alga at High Temperature
Authors: Ascione Richard , Southwick William , Fresco Jacques R.
Published: October 2006

Conditions for laboratory growth of the thermophilic alga
Cyanidium caldarium
at elevated temperatures have been developed. Growth characteristics of the organisms are described.
Pressure Regulation in the Middle Ear Cavity of Sea Lions: A Possible Mechanism
Authors: Odend'Hal Stewart , Poulter Thomas C.
Published: October 2006

The mucosa lining the cavity of the middle ear of sea lions contains a complex network of venous channels and sinuses. During dives the pressure within the middle ear may be equalized with that in the external auditory meatus either by the distention or depression of the mucosa due to the presence or absence of blood in the sinuses.
Multiple Causes and Controls in Differentiation
Authors: Wright Barbara E.
Published: October 2006

In this article the process of differentiation is analyzed, cell wall synthesis in a cellular slime mold being used as a model system. The causes and levels of control responsible for morphogenesis are many and complex; their interdependence must be understood in order to interpret their individual roles in the regulation of morphogenesis.
Thermal Recrystallization of Precipitated Zinc Sulfide
Authors: Bodi Lewis J. , Tufts Charles F.
Published: October 2006

Changes in morphology during thermal recrystallization of zinc sulfide precipitate were observed under an electron microscope. Intra-aggregate coalescence of precipitate grains proceeds with unexpected rapidity until the limiting identity of aggregate and grain is attained.
Undersea Air Supply
Authors: Vind Harold P.
Published: October 2006

The interior air of a simulated underwater habitation was continuously washed or scrubbed with sea water by means of a gas exchanger of the venturi type. The sole method for supplying oxygen and removing carbon dioxide was the scrubbing process. A microburner placed inside the experimental habitation chamber continued to burn until it was intentionally extinguished. Two rats maintained in the chamber for 8 hours suffered no discernible ill effects.
A Chemically Stratified Lake in Alaska
Authors: Likens G. E. , Johnson P. L.
Published: October 2006

A meromictic (chemically stratified) lake occupies a thawed depression in a pingo in interior Alaska, near Circle City. Increased salt concentration and anaerobic conditions characterize the zone extending from a maximum depth of 3 to 8.8 meters. The concentration of strontium and lithium is unusually high for lake water.
Selection of Sucrose-Dependent
Escherichia coli
To Obtain Envelope Mutants and Fragile Cultures
Authors: Mangiarotti Giorgio , Apirion David , Schlessinger David
Published: October 2006

Mutants isolated as sucrose-dependent include many with apparent envelope defects, which fact often leads to filamentous growth or lysis in the absence of sucrose. One mutant can grow exponentially in 4 percent sucrose, but is very fragile: it releases all of its RNA and soluble protein when treated with 0.5 percent sodium deoxycholate. These characteristics permit the study of unstable structures and rapid processes in actively growing cells.
Oxygen Fugacities Directly Measured in Magmatic Gases
Authors: Sato Motoaki , Wright Thomas L.
Published: October 2006

An electrochemical device was used to measure the fugacity of oxygen (
f

O
2

) in holes drilled through the crust of Makaopuhi lava lake, Kilauea Volcano, Hawaii. Results obtained within 6 months of the lake formation show that log
f

O
2

normally varies linearly with the reciprocal of the absolute temperature, and that chemical changes occurring in the cooling tholeiitic basalt are reflected in the
f

O
2

values measured in the holes.
Nucleic Acid Guanine: Reaction with the Carcinogen
N
-Acetoxy-2-Acetylaminofluorene
Authors: Miller Elizabeth C. , Juhl Ursula , Miller James A.
Published: October 2006

Reaction of
N
-acetoxy-2-acetylaminofluorene with DNA or RNA at
p
H 7 causes marked increase in absorption at 280 to 320 millimicrons and marked decrease in guanine content. Reaction with guanosine-8-
14
C yields a radioactive fluorescent derivative. The data suggest that metabolic esters of
N
-hydroxy-2-acetylaminofluorene may be intermediates in the binding of this proximate carcinogen to nucleic acids in vivo.
Odor Discrimination in Pigeons
Authors: Henton Wendon W. , Smith James C. , Tucker Don
Published: October 2006

An operant procedure was employed to investigate odor discrimination in the pigeon. Amyl acetate concentrations of 6-percent saturation in air, and lower, when paired with electric shock markedly reduced key-pecking during the odor stimulus period. Sectioning the olfactory nerves eliminated this selective suppression behavior. After the operation, the suppression was again conditioned when the concentration of amyl acetate was increased to 15-percent saturation in air. This is theoretically possible through mediation by the trigeminal system.
Severe Impairment of Heat-Induced Saliva-Spreading in Rats Recovered from Lateral Hypothalamic Lesions
Authors: Hainsworth F. Reed , Epstein Alan N.
Published: October 2006

A method has been devised to record saliva-spreading on fur and skin by rats in the heat. Normal males and females increase saliva-spreading with increasing ambient temperatures. Rats recovered from lateral hypothalamic lesions do not spread saliva in the heat, confirming the inference drawn from studies of their drinking behavior that their saliva production is severely impaired. Recovered lateral rats do produce saliva when injected with pilocarpine. The failure to salivate is, therefore, a result of the lateral hypothalamic lesions and is not due to an incompetence of the glands.
Gibberellin Production: Genetic Control in the Fungus
Gibberella fujikuroi
Authors: Spector Calvin , Phinney Bernard O.
Published: October 2006

The fungus
Gibberella fujikuroi
(Saw.) Wr. can be used in genetic studies of the production of gibberellins. A gene has been identified which controls a step in the biosynthetic pathway of gibberellin production. Apparently this step is early in the pathway for it affects the accumulation of all of the gibberellins produced by the fungus.
Rate of Protein Synthesis: Regulation during First Division Cycle of Sea Urchin Eggs
Authors: Sofer W. H. , George J. F. , Iverson R. M.
Published: October 2006

Protein synthesis in fertilized sea urchin eggs, or in 12,000
g
supernatants derived from them, increased linearly during the period preceding prophase of the first mitotic cycle, dropped during metaphase and anaphase, and increased again after telophase. Similar results were observed for whole cells incubated in the presence of colchicine. These changes in the rate of protein synthesis during the mitotic cycle may be regulated at the translational level.
Isolation of Nuclei from a Marine Dinoflagellate
Authors: Mendiola Leticia R. , Price C. A. , Guillard R. R. L.
Published: October 2006

By means of a medium containing dextran, nuclei were isolated in high yield from cells of
Gymnodinium nelsoni
, a marine dinoflagellate. Most of the DNA, but less than one-tenth of the RNA, of the original cells was recovered in the purified nuclei. The nuclei appeared substantially intact as observed by light or electron microscopy. The isolated nuclei were capable of incorporating tritiated uridine triphosphate into material insoluble in cold acid. The general procedure was found to be applicable also to two species of diatoms.
Protection of Macaques Against SIV Infection by Subunit Vaccines of SIV Envelope Glycoprotein gp160
Authors: Hu Shuu-Lok , Abrams Kraig , Barber Glen N. , Moran Patricia , Zarling Joyce M. , Langlois Alphonse J. , Kuller LaRene , Morton William R. , Benveniste Raoul E.
Published: October 2006

Simian immunodeficiency virus (SIV) is a primate lentivirus related to human immunodeficiency viruses and is an etiologic agent for acquired immunodeficiency syndrome (AIDS)-like diseases in macaques. To date, only inactivated whole virus vaccines have been shown to protect macaques against SIV infection. Protective immunity was elicited by recombinant subunit vaccines. Four
Macaca fascicularis
were immunized with recombinant vaccinia virus expressing SIV
mne
gp160 and were boosted with gp160 produced in baculovirus-infected cells. All four animals were protected against an intravenous challenge of the homologous virus at one to nine animal-infectious doses. These results indicate that immunization with viral envelope antigens alone is sufficient to elicit protective immunity against a primate immunodeficiency virus. The combination immunization regimen, similar to one now being evaluated in humans as candidate human immunodeficiency virus (HIV)-1 vaccines, appears to be an effective way to elicit such immune responses.
Mitochondrial Genetics: A Paradigm for Aging and Degenerative Diseases?
Authors: Wallace Douglas C.
Published: October 2006

Studies of diseases caused by mitochondrial DNA mutations suggest that a variety of degenerative processes may be associated with defects in oxidative phosphorylation (OXPHOS). Application of this hypothesis has provided new insights into such diverse clinical problems as ischemic heart disease, late-onset diabetes, Parkinson's disease, Alzheimer's disease, and aging.
Valuing the Health Benefits of Clean Air
Authors: Hall Jane V. , Winer Arthur M. , Kleinman Michael T. , Lurmann Frederick W. , Brajer Victor , Colome Steven D.
Published: October 2006

An assessment of health effects due to ozone and particulate matter (PM10) suggests that each of the 12 million residents of the South Coast Air Basin of California experiences ozone-related symptoms on an average of up to 17 days each year and faces an increased risk of death in any year of 1/10,000 as a result of elevated PM10exposure. The estimated annual economic value of avoiding these effects is nearly $10 billion. Attaining air pollution standards may save 1600 lives a year in the region.
Silicone Rubber: A New Diffusion Property Useful for General Anesthesia
Authors: Folkman Judah , Long David M. , Rosenbaum Richard
Published: October 2006

Ether, nitrous oxide, halothane, and cyclopropane diffuse through silicone rubber. General anesthesia can be produced in dogs by passing the vapors of any of these anesthetic agents through a coil of silicone rubber tubing, each end of which is placed in an artery and vein. Potential applications include a new method for general anesthesia and a simple accurate vaporizer for halothane.
Folk Taxonomies and Biological Classification
Authors: Berlin Brent , Breedlove Dennis E. , Raven Peter H.
Published: October 2006

A sample of 200 native plant names from the Tzeltal-speaking municipio of Tenejapa, Chiapas, Mexico, was found to consist of 41 percent that comprised more than one botanical species, 34 percent with a one-to-one correspondence, and 25 percent that referred to only a part of a botanical species. Cultural significance was least for the plants in the first group, greatest for those in the last group. Over half (60 percent) of the names for which there was one-to-one correspondence were plants associated with Hispanic culture, introduced as named entities following the Spanish conquest.
Paleomagnetic Study of Antarctic Deep-Sea Cores
Authors: Opdyke N. D. , Glass B. , Hays J. D. , Foster J.
Published: October 2006

The magnetic inclinations and intensities of about 650 samples from seven deep-sea cores taken in the Antarctic were measured on a spinner magnetometer. This series of measurements provided a magnetic stratigraphy, based on zones of normally or reversally polarized specimens for each core, which was then correlated with the magnetic stratigraphy of Cox
et al.
One core (V16-134) gave a continuous record of the paleomagnetic field back to about 3.5 million years.

When selected samples were subjected to alternating-field demagnetization, most were found to have an unstable component that was removed by fields of 150 oersteds; all samples from two cores were partially demagnetized in a field of 150 oersteds. The average inclination in these two cores was then in good agreement with the average inclination of the ambient field for the latitude of the core site. It was also found that the intensities of the samples decreased at the points of reversal; this finding is to be expected if, as has been postulated by the dynamo theory, the intensity of the dipole field decreases to zero and builds again with opposite polarity. We believe that the magnetization of the cores results from the presence of detrital magnetite, although other magnetic minerals also may be present.

Four faunal zones (φ, χ, ψ, and ω) have been recognized in these Antarctic cores on the basis of upward sequential disappearance of Radiolaria. The faunal boundaries and reversals consistently have the same relations to one another, indicating that they are both time-dependent phenomena.

Using previously determined times of reversal, one may date the following events in the cores:

1) Radiolarian faunal boundaries: φ-χ, 2 million years; χ-ψ, 0.7 million years; ψ-ω, 0.4 to 0.5 million years. These dates are in good agreement with ages previously extrapolated from radiometric dates.

2) Initiation of Antarctic diatom-ooze deposition, approximately 2.0 million years ago.

3) First occurrence of ice-rafted detritus, approximately 2.5 million years ago.

One can also calculate rates of sedimentation, which vary in the cores studied from 1.1 to about 8.0 millimeters per 1000 years. Sedimentation rates for the Indian Ocean cores are higher than for the Bellingshausen Sea cores. The near coincidence of faunal changes and reversals in the cores suggests but does not prove a causal relation.

We conclude from this study that paleomagnetic stratigraphy is a unique method for correlating and dating deep-sea cores, and that future work with such cores may provide a complete or nearly complete record of the history of the earth's magnetic field beyond 4 million years.
Meander in Valley Crossing a Deep-Ocean Fan
Authors: Shepard Francis P.
Published: October 2006

Seaward of most submarine canyons there are large sediment fans comparable to the fans at the base of mountain ranges. Many of the submarine fans are cut by valleys called fan-valleys which usually connect with the mouths of submarine canyons. Loop-like bends or meanders characterize the channels of rivers in their lower flood plains, but have never been found in the shallow channels that cross the alluvial fans at the base of mountain canyons. Therefore, it was surprising to find that the channel in a very deep submarine fan-valley off Monterey Bay, California, has a tight meander.
EDUCOM: Interuniversity Communications Council
Authors: Miller James G.
Published: October 2006

The Interuniversity Communications Council has been formed to provide collaboration among institutions of higher learning in their efforts to utilize the emerging communication sciences. Given a W. K. Kellogg Foundation grant for administration, eight charter members announced the nonprofit organization in June 1965. There now are 50 institutional members, representing 167 separate campuses. Interuniversity task forces have been assigned to the study of computerized regional and national educational information processing networks, educational systems and technology, computer-based systems for clinical activities, the copyright problems inherent in the new media, the use of the new information technologies in continuing education, and the use of computers in academic management. Other task forces will also be established.

All information-processing activities in higher education are of concern to EDUCOM, including computational use of computers, computerized programmed instruction, library automation, educational radio and television, computerized cognitive aids, and the use of computers in clinical operations and university administration. Its primary purposes are to organize interuniversity cooperation in these fields, to disseminate reports on the state of educational information technologies, to investigate areas of critical development, and to facilitate useful applications.
Pyrimidine Dimers: Effect of Temperature on Photoinduction
Authors: Rahn Ronald O.
Published: October 2006

Ultraviolet-induced pyrimidine dimer formation in DNA and polyuridylic acid was inhibited on irradiation at 77°K. Enhancement of thymine dimer formation in solutions of DNA occurred upon addition of ethylene glycol. Low temperature measurements of absorbance of polyuridylic acid at low temperature showed that no significant alteration of the residues occurred after irradiation at 77°K and before thawing.
Long-Term Activity Recording in Small Aquatic Animals
Authors: Heusher A. A. , Enright J. T.
Published: October 2006

We have built an activity-recording device based on the principle of detecting slight changes in the heat conductance of an aquatic environment by means of a thermistor. A major advantage of the device is that it can be used with a simple event recorder, thus combining high sensitivity with low cost. The equipment has been tested with automatic mechanical stimulation, and has been used for long-term recording of the swimming of small marine crustaceans. Problems of stability and reliability have been solved, and potential applications of the device seem widespread.
Replication of Adenovirus Type 7 in Monkey Cells: A New Determinant and Its Transfer to Adenovirus Type 2
Authors: Butel Janet S. , Rapp Fred , Melnick Joseph L. , Rubin Ben A.
Published: October 2006

A strain of human adenovirus type 7, adapted to replication in green-monkey kidney cells, requires the interaction of two particles to initiate plaque formation in the simian cells. One particle is a true adenovirion. The second, apparently defective, consists of a genome carrying a monkey-adapting component in an adenovirus capsid; this genome does not express known SV40 determinants. The addition of human adenovirus type 7 that is not adapted enhances the titer and changes conditions for plaque formation by the adapted virus to a one-particle requirement. Addition of nonadapted human adenovirus type 2 as helper virus results in the transfer of the monkey-adapting component from adenovirus type 7 to adenovirus type 2. The population containing the adenovirus 2 transcapsidant then has the ability to replicate in simian cells.
Liver Cancer: Neonatal Estrogen Enhances Induction by a Carcinogen
Authors: Weisburger J. H. , Yamamoto R. S. , Korzis J. , Weisburger E. K.
Published: October 2006

A single injection of 100 micrograms of estradiol benzoate into newborn rats was followed after weaning by dietary treatment with one of two dosages of the carcinogen N-hydroxy-
N
-2-fluorenylacetamide. Autopsies 26 weeks later showed a higher incidence of liver cancer in male and, particularly, female rats injected with hormone than in controls. The weights of livers were greater but gonads were smaller in size in the estradiol groups. Endocrine and possibly central-nervous-system factors may play roles in formation of liver tumors.
Inhibition of the Carotid Sinus Reflex by Stimulation of the Inferior Olive
Authors: Smith Orville A. , Nathan Marc A.
Published: October 2006

A projection of nerve fibers from rostral brainstem areas, which produce pressor responses and tachycardia, terminates in the inferior olive. Electrical stimulation of the olive in the cat produces no cardiovascular response but inhibits the depressor component of the carotid sinus reflex.
Cyanoacetylene in Prebiotic Synthesis
Authors: Sanchez R. A. , Ferris J. P. , Orgel L. E.
Published: October 2006

Cyanoacetylene is a major nitrogen-containing product of the action of an electric discharge on a mixture of methane and nitrogen. It reacts with simple inorganic substances in aqueous solution to give products including aspartic acid, asparagine, and cytosine.
Sediment Movement on the Continental Shelf near Washington and Oregon
Authors: Gross M. Grant , Nelson Jack L.
Published: October 2006

The nuclides zinc-65 and cobalt-60 associated with river-borne particulate matter are incorporated in sediment on the Continental Shelf near the Columbia River. Changes in the relative concentrations of zinc-65 and cobalt-60 and in the ratio of the activity of zinc-65 and cobalt-60 suggest that radioactive sediment moves northward 12 to 30 kilometers per year along the shelf and 2.5 to 10 kilometers per year westward away from the coast.
Reversible Inactivation of Aged Solutions of Indolyl-3-Acetic Acid
Authors: Bitancourt A. A.
Published: October 2006

Aqueous solutions of indole-3-acetic acid are inactivated by standing for a variable period of time. Inactivation results from conversion by oxidation of the plant hormone to polymerized deuterauxin, which is depolymerized by boiling of the solution, which restores activity.
Uranium and Lead Isotopic Stability in a Metamict Zircon under Experimental Hydrothermal Conditions
Authors: Pidgeon R. T. , O'Neil James R. , Silver Leon T.
Published: October 2006

Disturbance of the uranium-lead isotopic system in a metamict Ceylon zircon has been produced in a 2 molal NaCl solution at 500°C and 1000 bars fluid pressure. Loss of radiogenic lead to the extent of 61 percent in 13 days was the most significant effect. The experimental results support the episodic rather than continuous lead-loss interpretation of natural zircon systems utilized in geochronology.
Helium-Neon Laser: Thermal High-Resolution Recording
Authors: Carlson C. O. , Stone E. , Bernstein H. L. , Tomita W. K. , Myers W. C.
Published: October 2006

Scan-line recording by means of a moving laser spot has been achieved on metallic and organic thin films. Recording rates of the order of one million spots per second were obtained with a laser beam power of 38 milliwatts at the recording surface. Typical recorded line widths were of the order of 2 microns.
Sedimentary Environments in a Marine Marsh
Authors: Phleger Fred B. , Bradshaw John S.
Published: October 2006

Several foraminiferal assemblages are recognized in Spartina-Salicornia marshes along the Pacific and Gulf of Mexico coasts. Continuous recordings in one Pacific marsh show considerable diurnal and seasonal variation in
p
H, oxygen, water temperature, and salinity. This is related to tidal flushing, air temperature variations, sunlight duration, and marsh plant metabolism.
Sherman Landslide, Alaska
Authors: Shreve Ronald L.
Published: October 2006

Triggered by the earthquake of 27 March 1964, 3 × 10
7
cubic meters of rock fell 600 meters, then slid at high speed 5 kilometers across the nearly level Sherman glacier near Cordova. The landslide has a number of significant new features in addition to those typical of other large landslides that may have slid on a layer of trapped and compressed air.
Innovative Materials Processing Strategies: a Biomimetic Approach
Authors: Heuer A. H. , Fink D. J. , Laraia V. J. , Arias J. L. , Calvert P. D. , Kendall K. , Messing G. L. , Blackwell J. , Rieke P. C. , Thompson D. H. , Wheeler A. P. , Veis A. , Caplan A. I.
Published: October 2006

Many organisms construct structural ceramic (biomineral) composites from seemingly mundane materials; cell-mediated processes control both the nucleation and growth of mineral and the development of composite microarchitecture. Living systems fabricate biocomposites by: (i) confining biomineralization within specific subunit compartments; (ii) producing a specific mineral with defined crystal size and orientation; and (iii) packaging many incremental units together in a moving front process to form fully densified, macroscopic structures. By adapting biological principles, materials scientists are attempting to produce novel materials. To date, neither the elegance of the biomineral assembly mechanisms nor the intricate composite microarchitectures have been duplicated by nonbiological processing. However, substantial progress has been made in the understanding of how biomineralization occurs, and the first steps are now being taken to exploit the basic principles involved.
An Unstable Triplet Repeat in a Gene Related to Myotonic Muscular Dystrophy
Authors: Fu Y. H. , Pizzuti A. , Fenwick R. G. , King J. , Rajnarayan S. , Dunne P. W. , Dubel J. , Nasser G. A. , Ashizawa T. , de Jong P. , Wieringa B. , Korneluk R. , Perryman M. B. , Epstein H. F. , Caskey C. Thomas
Published: October 2006

Synthetic oligonucleotides containing GC-rich triplet sequences were used in a scanning strategy to identify unstable genetic sequences at the myotonic dystrophy (DM) locus. A highly polymorphic GCT repeat was identified and found to be unstable, with an increased number of repeats occurring in DM patients. In the case of severe congenital DM, the paternal triplet allele was inherited unaltered while the maternal, DM-associated allele was unstable. These studies suggest that the mutational mechanism leading to DM is triplet amplification, similar to that occurring in the fragile X syndrome. The triplet repeat sequence is within a gene (to be referred to as myotonin-protein kinase), which has a sequence similar to protein kinases.
Tactoid Formation in Montmorillonite: Effect on Ion Exchange Kinetics
Authors: Banin Amos
Published: October 2006

Exchange between calcium from montmorillonite and hydrogen from resin is much slower than exchange between sodium from montmorillonite and hydrogen from resin. Film kinetics are prevailing in both cases, but the location of the rate-determining step is shifted from the Nernst films of the resin particles in the sodium-hydrogen exchange to the Nernst films of the clay particles in the calcium-hydrogen exchange. The increased particle size of the montmorillonite in the calcium state, caused by tactoid formation, appears to be the main reason for the shift.
Fungicidal Phthalimidophosphonothionates
Authors: Tolkmith Henry , Senkbeil H. O. , Mussell Dorsey R.
Published: October 2006

The fungicidal activity, mammalian toxicity, and methods of synthesis of
phthalimidophosphonothionates, a novel type of organophosphoramide compound, have been
investigated. The findings led to development of the compound diethyl
phthalimidophosphonothionate as a new bioproduct. This diester protects a variety of crops
from certain plant diseases, such as powdery mildew, apple scab, leaf spot, brown rot, and
black spot.
D-Gluconic Acid: Isolation from the Defensive Secretion of the Cockroach
Eurycotis decipiens
Authors: Dateo George P. , Roth Louis M.
Published: October 2006

The major water-soluble constituent of the defensive secretion of
Eurycotis decipiens
was identified as gluconic acid, isolated in the form of calcium D-gluconate. The acid, in equilibrium with its lactones, is present in unusually high concentration.
Superconductivity and the
d
-Shell
Authors: Engelhardt John J. , Webb George W. , Matthias Bernd T.
Published: October 2006

The various isotope effects on the superconducting transition temperature of Mo
2
B and W
2
B have been measured. Together with resistivity data they indicate that the
d
-shell forms a highly stable electron configuration for molybdenum and tungsten. This leads to an understanding of high superconducting transition temperatures.
Tryptophan Hydroxylation: Measurement in Pineal Gland, Brainstem, and Carcinoid Tumor
Authors: Lovenberg Walter , Jequier Eric , Sjoerdsma Albert
Published: October 2006

Development of a rapid and sensitive radioassay has permitted study of the conversion of tryptophan to 5-hydroxytryptophan in mammalian tissues. Of normal tissues examined, beef and rat pineal gland contained the highest activity. This is the first direct demonstration of tryptophan hydroxylase in this hydroxyindole-rich tissue. Rat and rabbit brainstem and human carcinoid tumor also had quantities of enzyme that could be measured easily. The reaction requires a reduced pteridine and oxygen and is inhibited by para-chlorophenylalanine.
Passive Transfer of Tuberculin Reactivity in Vitro
Authors: Fireman Philip , Boesman Mary , Haddad Zaky H. , Gitlin David
Published: October 2006

A factor capable of effecting passive transfer in vivo of delayed hypersensitivity to tuberculin to recipients that are tuberculin negative was isolated from the dialyzate of disrupted leukocytes of tuberculin-positive individuals. After this factor was incubated with cultures of peripheral leukocytes from tuberculin-negative individuals, the addition of purified protein derivative of tubercle bacilli resulted in leukocyte stimulation similar to that observed after addition of purified protein derivative to leukocytes from tuberculin-positive individuals.
Opposite Synaptic Actions Mediated by Different Branches of an Identifiable Interneuron in
Aplysia
Authors: Kandel E. R. , Frazier W. T. , Coggeshall R. E.
Published: October 2006

Among the identifiable cells in the abdominal ganglion of
Aplysia californica
are five that generate bursting rhythms endogenous to the cells. In the four bursting cells of the left upper quadrant the rhythm is modulated by a unitary inhibitory postsynaptic potential; in the bursting cell of the right lower quadrant the rhythm is modulated by a unitary excitatory postsynaptic potential. Both the excitatory and inhibitory postsynaptic potentials are mediated by separate branches of a single interneuron. The pharmacological properties of the double action interneuron as well as those of the follower cells suggest that a single transmitter (acetylcholine) is involved in both the excitatory and the inhibitory action of the interneuron.
Amphibian Orientation: An Unexpected Observation
Authors: Twitty Victor , Grant David , Anderson Oscar
Published: October 2006

The study of homing movements of displaced newts (
Taricha rivularis
) revealed unexpected features of the migratory behavior of amphibians. Newts leaving the breeding stream in the spring move not directly uphill but at an angle carrying them upstream. When they emerge after summer estivation this tendency is not evident in captures made during the autumn and winter. During the latter period, however, newly metamorphosed frogs (
Rana boylii
) show the same pronounced upstream migration that characterizes
T. rivularis
in the spring.
Genomic Exclusion: A Rapid Means for Inducing Homozygous Diploid Lines in
Tetrahymena pyriformis
, Syngen 1
Authors: Allen Sally Lyman
Published: October 2006

Genomic exclusion is an abnormal form of conjugation occurring between cells with defective micronuclei and normal cells with diploid micronuclei. The progeny are heterocaryons; each cell has an old macronucleus but a new diploid micronucleus derived from one meiotic product of the normal mate. Such cells express genes found in the old macronucleus, are sexually mature, and can be specifically selected. When inbred, they give rise to lines genetically homozygous at all known loci.
Neural Basis of the Sense of Flutter-Vibration
Authors: Mountcastle Vernon B. , Talbot William H. , Darian-Smith Ian , Kornhuber† Hans H.
Published: October 2006

Comparison of human detection thresholds for oscillatory movement of the skin of the hand with response properties of first-order myelinated mechanoreceptive afferents from the monkey's hand, activated in an identical stimulus pattern, indicates that flutter-vibration is a dual form of mechanical sensibility, served peripherally by two different sets of fibers.
Frog Cerebellum: Absence of Long-Term Inhibition upon Purkinje Cells
Authors: Llinás R. , Bloedel J. R.
Published: October 2006

Electrophysiological studies of the cerebellar cortex of the frog demonstrate a lack of long-term inhibition upon the Purkinje cells. This lack of inhibition correlates well with the absence of stellate and basket cells in the molecular layer of this cerebellum and strongly supports the idea that these interneurones are the agents responsible for the prolonged inhibition seen in the Purkinje cells of other species.
Magnesium Pemoline: Lack of Facilitation in Human Learning, Memory, and Performance Tests
Authors: Smith Ronald G.
Published: October 2006

Either a placebo or 25 or 37.5 milligrams of magnesium pemoline was administered on a double-blind basis to three intelligence-matched groups of normal, adult males. Learning and 24-hour retention tests included verbal learning, motor learning, and classical conditioning. Short-term memory tests were administered through both the visual and auditory modalities. Arm-hand steadiness and visual reaction time performance tests were included. The only measures revealing significant group differences showed the performance of subjects given pemoline was inferior to that of subjects given a placebo.
Autosomal Deletion Mapping in Man
Authors: Nance Walter E. , Engel Eric
Published: October 2006

Two families were observed in which morphologically similar deletions involving a G-group chromosome were associated in the propositi with conspicuous abnormalities in ossification of the skull. The findings suggest that specific genetic information relating to morphogenesis of the skull may be located on a G-group chromosome.
Structural Aspects of Reversible Molecular Oxygen Uptake
Authors: McGinnety J. A. , Doedens Robert J. , Ibers James A.
Published: October 2006

The system IrX(CO)[P(C
6
H
5
)
3
]
2
in benzene solution adds molecular oxygen reversibly if X is chlorine and irreversibly if X is iodine. The crystal structure of the complex IrIO
2
(CO)[P(C
6
H
5
)
3
]
2
⋅ CH
2
Cl
2
is reported here and compared with a previous study of the structure of IrClO
2
(CO)[P(C
6
H
5
)
3
]
2
. The O—O bond length is 1.47 ± 0.02 angstroms in the irreversibly oxygenated iodo-compound and 1.30 ± 0.03 angstroms in the reversibly oxygenated chloro-compound.
Brain Stem Structures Responsible for the Electroencephalographic Patterns of Desynchronized Sleep
Authors: Candia O. , Rossi G. F. , Sekino T.
Published: October 2006

Contrary to the results of transecting one half of the rostral pons, unilateral partial lesions of the rostral pons, involving either "specific" or "aspecific" structures, do not prevent the appearance of the desynchronized electroencephalographic patterns of deep sleep in the ipsilateral hemisphere in cats. This effect, however, is obtained by lesions of the medial as well as lateral tegmental structures of the midbrain. These findings seem to indicate that (i) there is not a single pontine structure or group of structures of crucial importance for the EEG desynchronization of deep sleep; the whole rostral pons appears to contribute to the EEG-desynchronizing influence; (ii) this influence runs rostrally through the midbrain tegmentum, without following any known fiber pathway.
Leukocyte Oxidase: Defective Activity in Chronic Granulomatous Disease
Authors: Baehner Robert L. , Nathan David G.
Published: October 2006

The intact leukocytes of two children with chronic granulomatous disease fail to reduce nitroblue tetrazolium during phagocytosis. This is due to defective operation of an oxidase of reduced nicotinamide adenine dinucleotide that is insensitive to cyanide and that indirectly stimulates the oxidation of glucose-6-phosphate in leukocytes. Such leukocytes undergo no increase in oxygen consumption or in activity of the hexose monophosphate shunt during phagocytosis, although lactate production is normal. The addition of nitroblue tetrazolium to a leukocyte suspension appears to provide a sensitive diagnostic screening test for this disease.
Sporulation Mutations Induced by Heat in
Bacillus subtilis
Authors: Northrop J. , Slepecky R. A.
Published: October 2006

When spores of
Bacillus subtilis
strain Marburg are heated (90° to 100°C) in a vacuum for 9 to 12 hours and then plated, numerous mutants are obtained, and very few spores are killed. Disproportionately large numbers of these mutants exhibit abnormal sporulation.
Radiation of Hemocyanin: Inactivation and Reactivation of Oxygen-Carrying Capacity
Authors: Schubert Jack , White E. R.
Published: October 2006

Oxygen-carrying capacity of hemocyanin from
Limulus
and
Busycotypus
(
Busycon
) decreases with increasing radiation, giving initial yield values for
G
(—O
2
) of 1.1 and 1.0, respectively. High radiation doses regenerate this capacity of
Busycotypus
hemocyanin. These effects are attributed largely to the dual nature of hydrogen peroxide, which, at low concentrations, oxidizes protein-bound copper and at high concentrations, that is, at high doses, reduces oxidized copper. The ability of hemocyanin to decompose hydrogen peroxide is relatively unaffected by irradiation, which suggests that copper atoms at the active sites are not all equivalent. The catalase-like activity of
Busycotypus
hemocyanin can be simulated by amino acid chelates of copper, including arginine, histidine, and glycine.
Composition of the Ancient North American Crust
Authors: Condie Kent C.
Published: October 2006

Geochemical studies of Wyoming Precambrian graywackes derived from continental crust older than 3.2 × 10
9
years indicate that their source area was at least as highly differentiated as most younger Precambrian crust. The composition of this early crust (approximately that of calcium-rich granite) is not unlike that of the 2.5 to 3.2 × 10
9
year old North American crust. Limited geochemical data suggest that the composition of North America may not have changed significantly during the last 3.0 to 3.5 × 10
9
years.
Retinal Ganglion Cells: Specification of Central Connections in Larval
Xenopus laevis
Authors: Jacobson Marcus
Published: October 2006

In a series of
Xenopus
larvae (stages 28 to 35), the left eye cup was dorsoventrally and anteroposteriorly inverted. After metamorphosis, the retinotectal projection was mapped by recording action potentials evoked in the tectum by a small spot of light projected on the retina. Normal retinotectal projection was found following rotation of the eye cup at stage 28 to 29. Rotation of the eye cup at stage 30 resulted in anteroposterior inversion of the retinotectal projection; rotation at stages 31, 32, and 35 resulted in inversion of the projection in anteroposterior and dorsoventral axis of the retina. Therefore the retinal ganglion cells were unspecified at stage 28 to 29; spatial specification of ganglion cells occurred in the anteroposterior axis of the eye cup at stage 30 and in the dorsoventral axis between stages 30 and 31.
Rhodopsin: Responses from Transient Intermediates Formed during Its Bleaching
Authors: Pak William L. , Boes Robert J.
Published: October 2006

Fast electrical responses elicited from the transient intermediates in the bleaching of rhodopsin have been investigated in the retina of the albino rat. In the experiments we used two-flash stimuli triggered sequentially with a continuously variable time delay between them. At room temperature the potential is biphasic in wave-form. The dominant, corneal-positive component is preceded by a small, corneal-negative component. Cooling the retina to about 0°C suppresses the positive component and isolates the faster, negative component. Experiments with color filters show that these two components display different spectral sensitivities and, hence, suggest that each of them is produced by a different photoproduct of bleaching.