bluuebunny/crossref_metadata_2025 huggingface dataset:
Coding Properties of 7-Methylguanine
Authors: Wilhelm Robert C. , Ludlum David B.
Published: October 2006

The abnormal base, 7-methylguanine, has been introduced into copolymers of uridylic and guanylic acids by methylation under controlled conditions. The resulting methylated copolymers have a markedly decreased template activity for polypeptide synthesis in vitro due to steric effects of the 7-methyl groups. Contrary to expectation, these polymers do not permit incorporation of amino acids whose codons contain the bases uracil and adenine.
Pacemaker Synchronization
Authors: Anagnostopoulos C. E. , Holcomb W. G. , Glenn W. W. L.
Published: October 2006

A method using the standard radio-frequency receiver was developed to telemeter biopotentials across the intact body wall; it can be employed to program a stimulus to the heart at any phase of the cardiac cycle. The small variations of potential across the electrodes of the implanted cardiac pacemaker change the natural resonant frequency of the receiver in direct relation to the electrical activity of the heart.
Homoreactant: A Naturally Occurring Autoantibody in Rabbits
Authors: Mandy William J. , Kormeier Lucy C.
Published: October 2006

Homoreactant, a factor found in the serum of every normal rabbit tested thus far, reacts specifically with buried antigenic determinants on the Fab-fragment of papain-digested autologous and homologous γG-globulin. It appears that rabbits normally produce naturally occurring autoantibodies.
Acceleration of Ureteral Peristalsis by Adrenal Compression
Authors: Boyarsky Saul , Labay Peregrina , Kirshner Norman
Published: October 2006

Unilateral adrenal compression resulted in bilateral acceleration of ureteral peristalsis which could be reversed by an injection of alpha-adrenergic inhibitor, providing additional evidence for the presence of adrenergic receptors in the ureter.
Juvenile Hormone: Identification of an Active Compound from Balsam Fir
Authors: Bowers W. S. , Fales H. M. , Thompson M. J. , Uebel E. C.
Published: October 2006

A sesquiterpenoid ester with high juvenile hormone activity for
Pyrrhocoris apterus
(L.) was isolated from balsam fir,
Abies balsamea
(L.) Miller, and identified as the methyl ester of todomatuic acid.
Proliferation of Cells in the Central Cylinder of the Reduced Mutant in Lanceolate Tomato
Authors: Caruso John L. , Cutter Elizabeth G.
Published: October 2006

When the reduced phenotype in homozygous lanceolate tomato is cultured on a sterile nutrient medium, there is a considerable amount of cell division within the central cylinder. Such proliferation may occur in response to a stimulus furnished to the shoot by the root.
X-ray Detection by the Olfactory System: Ozone as a Masking Odorant
Authors: Gasteiger Edgar L. , Helling Sharon A.
Published: October 2006

The technique of masking was used to test the hypothesis that x-ray detection is mediated by an odorant produced in irradiated air. Rats conditioned to cease licking during exposure to x-ray (conditioned suppression) did not display this conditioned response in the presence of ozone and strong volatile oxidants.
Vesicular Stomatitis Virus Replication in Human Leukocyte Cultures: Enhancement by Phytohemagglutinin
Authors: Edelman Robert , Wheelock E. Frederick
Published: October 2006

The replication of vesicular stomatitis virus in human leukocyte cultures shows that virus yields can be enhanced 6- to 180-fold by treating the leukocyte cultures with phytohemagglutinin prior to virus inoculation. Data suggest that a substance is produced in phytohemagglutinin-treated leukocyte cultures which is capable, on transfer to fresh leukocytes, of inducing blast cell formation and enhancing virus replication.
Magnetic Anomalies over the Pacific-Antarctic Ridge
Authors: Pitman W. C. , Heirtzler J. R.
Published: October 2006

Four magnetic profiles across the Pacific-Antarctic Ridge reveal magnetic anomalies that show trends parallel with the ridge axis and symmetry about the ridge axis. The distribution of bodies that could cause these anomalies supports the Vine and Matthews hypothesis for the generation of patterns of magnetic anomalies associated with the midocean ridge system. The geometry of the bodies accords with the known reversals of the geomagnetic field during the last 3.4 million years, indicating a spreading rate of the ocean floor of 4.5 centimeters per year. If one assumes that the spreading rate within 500 kilometers of the ridge axis has been constant, reversals of the geomagnetic field during the last 10.0 million years can be determined. This new, detailed history of field reversals accords with observed anomalies over Reykjanes Ridge in the North Atlantic if a spreading rate of 1 centimeter per year is assumed there.
Thiamine Pyrophosphate Hydrochloride: Stereochemical Aspects from an X-Ray Diffraction Study
Authors: Pletcher James , Sax Martin
Published: October 2006

The crystal structure of thiamine pyrophosphate has been determined by a three-dimensional x-ray analysis. The conformation of the molecule in the crystalline state is determined by the formal charge distribution within the molecule which exists as a zwitterion with the negative pyrophosphate chain folded back over the positive, ring portion of the molecule. The oxygen atoms in the pyrophosphate group are in the staggered conformation when viewed along the phosphorus-phosphorus axis. Even though the pyrophosphate is present in this compound as the monoionized monoester, the configuration is the same as that present in the inorganic pyrophosphate ion. From a comparison of three different crystal structures containing the thiamine moiety and from studies with atomic models, it seems plausible that the basic molecular conformation observed in this crystal is maintained in the catalytically active molecule. Knowledge of the detailed crystal structure provides new insight into the biochemical mechanism of reactions catalyzed by thiamine pyrophosphate.
Protoperithecia in
Neurospora crassa
: Technique for Studying Their Development
Authors: Rothschild Henry , Suskind Sigmund R.
Published: October 2006

A technique is described which facilitates analysis of the development of individual protoperithecia in
Neurospora crassa
. The formation of this organelle proceeds in several clearly discernible steps beginning with the looping of a single hyphal filament and ending with a heavily pigmented, densely packed structure that is the mature protoperithecial structure. The effects of a number of environmental conditions on the development of protoperithecia in two wild types and in a female-sterile mutant strain, ty-1, are presented.
Spreading of the Ocean Floor: New Evidence
Authors: Vine F. J.
Published: October 2006

It is suggested that the entire history of the ocean basins, in terms of ocean-floor spreading, is contained frozen in the oceanic crust. Variations in the intensity and polarity of Earth's magnetic field are considered to be recorded in the remanent magnetism of the igneous rocks as they solidified and cooled through the Curie temperature at the crest of an oceanic ridge, and subsequently spread away from it at a steady rate. The hypothesis is supported by the extreme linearity and continuity of oceanic magnetic anomalies and their symmetry about the axes of ridges.

If the proposed reversal time scale for the last 4 million years is combined with the model, computed anomaly profiles show remarkably good agreement with those observed, and one can deduce rates of spreading for all active parts of the midoceanic ridge system for which magnetic profiles or surveys are available. The rates obtained are in exact agreement with those needed to account for continental drift.

An exceptionally high rate of spreading (approximately 4.5 cm/year) in the South Pacific enables one to deduce by extrapolation considerable details of the reversal time scale back to 11.5 million years ago. Again, this scale can be applied to other parts of the ridge system. Thus one is led to the suggestion that the crest of the East Pacific Rise in the northeast Pacific has been overridden and modified by the westward drift of North America, with the production of the anomalous width and unique features of the American cordillera in the western United States. The oceanic magnetic anomalies also indicate that there was a change in direction of crustal spreading in this region during Pliocene time from eastwest to southeast-northwest.

A profile from the crest to the boundary of the East Pacific Rise, and the difference between axial-zone and flank anomalies over ridges, suggest increase in the frequency of reversal of Earth's magnetic field, together, possibly, with decrease in its intensity, approximately 25 million years ago.

Within the framework of ocean-floor spreading, it is suggested that magnetic anomalies may indicate the nature of oceanic fracture zones and distinguish the parts of the ridge system that are actively spreading. Thus data derived during the past year lend remarkable support to the hypothesis that magnetic anomalies may reveal the history of the ocean basins.
Calcite: Rates of Dissolution in a Vertical Profile in the Central Pacific
Authors: Peterson M. N. A.
Published: October 2006

Rate of dissoluton of calcium carbonate (calcite) was determined for a vertical profile 5000 meters deep in the central Pacific by measuring the loss of weight of optical calcite spheres arrayed on a mooring. Waters of the Pacific are undersaturated in all but the upper several hundred meters. A sharp increase in the rate of dissolution occurs at a depth of about 3700 meters, which corresponds closely to the depth below which calcite has been dissolved from the sediments.
Hormonal Termination of Diapause in the Alfalfa Weevil
Authors: Bowers W. S. , Blickenstaff C. C.
Published: October 2006

Topical treatment of the alfalfa weevil,
Hypera postica
(Gyllenhal), with the synthetic juvenile gonadotropic hormone 10,11-epoxyfarnesenic acid methyl ester effectively terminated summer diapause.
Reversal of Diabetes Insipidus in Brattleboro Rats: Intrahypothalamic Injection of Vasopressin mRNA
Authors: Jirikowski Gustav F. , Sanna Pietro Paolo , Maciejewski-Lenoir Dominique , Bloom Floyd E.
Published: October 2006

Messenger RNAs occur within the axons of magnocellular hypothalamic neurons known to secrete oxytocin and vasopressin. In Brattleboro rats, which have a genetic mutation that renders them incapable of vasopressin expression and secretion and thus causes diabetes insipidus, injection into the hypothalamus of purified mRNAs from normal rat hypothalami or of synthetic copies of the vasopressin mRNA leads to selective uptake, retrograde transport, and expression of vasopressin exclusively in the magnocellular neurons. Temporary reversal of their diabetes insipidus (for up to 5 days) can be observed within hours of the injection. Intra-axonal mRNAs may represent an additional category of chemical signals for neurons.
Myotonic Dystrophy Mutation: an Unstable CTG Repeat in the 3′ Untranslated region of the Gene
Authors: Mahadevan Mani , Tsilfidis Catherine , Sabourin Luc , Shutler Gary , Amemiya Chris , Jansen Gert , Neville Catherine , Narang Monica , Barceló Juana , O'Hoy Kim , LeBlond Suzanne , Earle-MacDonald Jane , de Jong Pieter J. , Wieringa Bé , Korneluk Robert G.
Published: October 2006

Myotonic dystrophy (DM) is the most common inherited neuromuscular disease in adults, with a global incidence of 1 in 8000 individuals. DM is an autosomal dominant, multisystemic disorder characterized primarily by myotonia and progressive muscle weakness. Genomic and complementary DNA probes that map to a 10-kilobase Eco RI genomic fragment from human chromosome 19q13.3 have been used to detect a variable length polymorphism in individuals with DM. Increases in the size of the allele in patients with DM are now shown to be due to an increased number of trinucleotide CTG repeats in the 3′ untranslated region of a DM candidate gene. An increase in the severity of the disease in successive generations (genetic anticipation) is accompanied by an increase in the number of trinucleotide repeats. Nearly all cases of DM (98 percent or 253 of 258 individuals) displayed expansion of the CTG repeat region. These results suggest that DM is primarily caused by mutations that generate an amplification of a specific CTG repeat.
Regulation of
jun
-B Messenger RNA and AP-1 Activity by Light and a Circadian Clock
Authors: Kornhauser Jon M. , Nelson Dwight E. , Mayo Kelly E. , Takahashi Joseph S.
Published: October 2006

The suprachiasmatic nuclei (SCN) of the hypothalamus comprise the primary pacemaker responsible for generation of circadian rhythms in mammals. Light stimuli that synchronize this circadian clock induce expression of the c-
fos
gene in rodent SCN, which suggests a possible role for Fos in circadian entrainment. Appropriate light stimuli also induce the expression of
jun
-B messenger RNA in the SCN of golden hamsters but only slightly elevate c-
jun
messenger RNA levels. In addition, light increases the amount of a protein complex in the SCN that binds specifically to sites on DNA known to mediate regulation by the AP-1 transcription factor. The photic regulation of both
jun
-B messenger RNA expression and AP-1 binding activity is dependent on circadian phase: only light stimuli that shift behavioral rhythms induce
jun
-B and AP-1 expression. Thus, light and the circadian pacemaker interact to regulate a specific set of immediate-early genes in the SCN that may participate in entrainment of the circadian clock.
Effects of Tetrodotoxin on Excitability of Squid Giant Axons in Sodium-Free Media
Authors: Watanabe Akira , Tasaki Ichiji , Singer Irwin , Lerman Lawrence
Published: October 2006

The effect of tetrodotoxin on excitability of internally perfused squid giant axons immersed in various sodium-free media was examined. Action potentials were found to be suppressed by this substance, with or without sodium ion in the external medium. Tetrodotoxin showed a strong suppressive effect upon action potentials produced in media containing salts of only divalent cations (CaCl
2
, CaBr
2
, SrCl
2
, or BaCl
2
). Our findings concerning the action of tetrodotoxin do not support the separate-channel hypothesis for excitable membranes.
Tracks of Cosmic Rays in Plastics
Authors: Fleischer R. L. , Price P. B. , Walker R. M. , Filz R. C. , Fukui K. , Friedlander M. W. , Holeman E. , Rajan R. S. , Tamhane A. S.
Published: October 2006

Cosmic ray nuclei have been observed with the use of plastic track-detecting solids in satellites and high-altitude balloon flights. Nuclear emulsions in the stacks of plastic sheets allowed the positive identification of cosmic ray nuclei as light as nitrogen. The most striking new information was the failure to observe relativistic iron nuclei, a result which has led to an advance in the understanding of track registration criteria.
Mutations, Chromosomal Aberrations, and Tumors in Insects Treated with Oncogenic Virus
Authors: Burdette Walter J. , Yoon Jong Sik
Published: October 2006

An increased incidence of lethal mutations, visible mutations, chromosomal losses, chromosomal nondisjunctions, and tumors resulted when drosophila were placed in medium containing Rous-sarcoma virus. In the group treated, a few mosaics of the eye and translocations appeared as well. There is a suggestion, from preliminary data, that the size of chromosomal puffs may be reduced by this RNA virus, but the difference is not significant. Tests for the persistence of virus in progeny have been negative so far.
Mechanisms of Organic Oxidation and Reduction by Metal Complexes
Authors: Kochi Jay K.
Published: October 2006

The mechanism of many organic oxidation and reduction reactions can be described in terms of the formation and reaction of free radicals with metal complexes. Redox (trace-metal) catalysis also involves the oxidation and reduction of radical intermediates with a metal species which oscillates between several oxidation states.

The oxidation and reduction of free radicals with metal complexes follow two general mechanisms, electron transfer and ligand transfer. Direct analogy exists with wholly inorganic descriptions of outer-sphere and innersphere processes.

In an electron transfer or outersphere mechanism the redox process is derived largely by transfer of an electron from reductant to oxidant, with only indirect contributions from the solvent and ligand. Carbonium ion intermediates and transition states are important considerations, and the scission of the β-hydrogen bond is minor during oxidation of alkyl radicals to alkenes. In contrast, ligand transfer or inner-sphere mechanism demands maximum involvement of the ligand in the transition state. Free-radical character prevails; cationic contributions from the organic moiety are minimal.

Oxidation and reduction are conjugate processes. In an electron transfer mechanism the oxidation of alkyl radicals to carbonium ions is conceptually represented by a microscopic reverse reaction in which a carbonium ion is reduced to an alkyl radical. A similar duality exists in the interconversion of carbanions and free radicals by metal complexes.

The reversibility of the ligand transfer process is easier to observe. For example, the chlorine-transfer oxidation of alkyl radicals is represented by a microscopic reverse reduction of alkyl chlorides to alkyl radicals by cuprous chlorides. A ligand transfer counterpart of the
reduction
of radicals

R"⋅+Cu
II
Cl

n

⇋R-Cl+Cu
I
Cl

n
n-1

can also be described.

Hopefully, these simple redox mechanisms will be utilized in rationalizing complex reactions and formulating new syntheses. The limited number of examples cited in this short review represent only an introduction to the vast area of chemical research to be tapped in the study of the mechanisms and the synthetic utility of oxidation-reduction reactions and catalysis.
Niningerite: A New Meteoritic Sulfide
Authors: Keil Klaus , Snetsinger K. G.
Published: October 2006

Niningerite, a new meteoritic sulfide ranging in composition from (Fe
0.19
Mg
0.66
Mn
0.14
Ca
0.007
Cr
0.002
)S to (Fe
0.52
Mg
0.33
Mn
0.06
Ca
0.06
Cr
0.03
Zn
0.004
)S, from the type-I enstatite chondrites Abee, Saint Sauveur, Adhi-Kot, Indarch, St. Mark's, and Kota-Kota, is described. It is named in honor of H. H. Nininger.
Human Echo Perception
Authors: Rice Charles E.
Published: October 2006

It has been shown that human test subjects have the ability, under controlled laboratory conditions, to use echoes to detect the presence or absence of targets placed before them. In addition, blind and sighted persons have been able to detect a target monaurally, to make simple shape discriminations, and to locate a target in space. Signal, environmental, and individual variability affect performance in a measurable fashion.

This research is an initial step in measuring the limits of a human being's ability to use echoes as a source of information about his physical surroundings. At this point it seems unlikely that the unaided human ear can rival the bat's auditory system for echo perception. It may be, however, that modern technology can partially bridge the evolutionary gap and bring more useful echoes to man's ear than those it now receives. Such an accomplishment would allow us to examine the extent to which man might benefit from this means of sensing his environment.
Visually Guided Reaching in Infant Monkeys after Restricted Rearing
Authors: Held Richard , Bauer Joseph A.
Published: October 2006

Infant macaques were reared from birth in an apparatus which precluded sight of their body parts. At 35 days postpartum one hand was exposed to view. Visual fixation of this hand was insistent and prolonged; visually guided reaching was poor, but it improved during ten succeeding hours of exposure. Little concomitant improvement occurred in the reaching of the unexposed hand.
Purified Staphylococcal Alpha Toxin: Effect on Epithelial Ion Transport
Authors: Rahal James J. , Plaut Martin E. , Rosen Herman , Weinstein Louis
Published: October 2006

Purified staphylococcal alpha toxin, when added to the serosal bathing medium of the isolated toad bladder, causes a rapid fall in short-circuit current and transepithelial potential difference. It has no effect when added to the mucosal bathing medium. Oxygen consumption by suspensions of minced bladder tissue is stimulated by the toxin. These effects are neutralized by staphylococcal antitoxin.
Fossilization of an Ancient (Devonian) Soft-Bodied Worm
Authors: Cameron Barry
Published: October 2006

A shell-boring polychaete worm was found replaced by the mineral limonite-goethite; this fossil is probably a limonite-goethite pseudomorph after pyrite, suggesting that the soft-bodied worm was originally replaced by pyrite. External structures such as a prostomium, anterior tentacle-like palps, peristomial cirri, parapodia, setae bundles of the parapodia, and dorsal cirri of the parapodia are preserved. This worm resembles living members of the family Spionidae in form and habit. This discovery extends the known range of this family (Cretaceous?, Miocene to Recent) back about 365 million years to the Devonian period.
Gametophytes of Four Tropical Fern Genera Reproducing Independently of Their Sporophytes in the Southern Appalachians
Authors: Farrar Donald R.
Published: October 2006

Vegetative reproduction and dispersal by way of gemmae are known to occur in four types of fern gametophytes. Although they belong to basically tropical rain-forest genera, all four types have now been discovered growing naturally in the vicinity of Highlands, North Carolina, as clones on shady, damp rocks. Their sporophytes were rare or absent. The gametophytes are now identified as
Grammitis nimbata
(Jenm.) Proctor, Grammitidaceae;
Hymenophyllum tunbridgense
(L.) J. Sm., Hymenophyllaceae;
Vittaria lineata
(L.) J. Sm., Vittariaceae; and
Trichomanes
, probably representing several species, Hymenophyllaceae. Identification of the
Grammitis
was facilitated by the presence of some juvenile or dwarfed sporophytes; this constitutes the first report of this species, genus, and family for temperate North America. Growth and spread of fern gametophytes independently of, and distant from, the corresponding sporophytes is a novel phenomenon which should be investigated in other parts of the world.
Ecological Dosimetry: Radiation Levels Influenced by Plant Growth
Authors: Ashby William C. , Beggs James N. , Kastner Jacob , Oltman B. G. , Moses Harry
Published: October 2006

The feasibility of using lithium-7-fluoride thermoluminescent dosimeters under field conditions for natural radiation at levels of 5 milliroentgens is demonstrated. Radiation dosages in tree trunks increased threefold from winter to spring and summer. This increase is attributed to the gamma radiation field resulting from relatively high levels of potassium-40 and other radionuclides present in the foliage and branches during the growing season.
Ribonuclease Activity in Normal and
Opaque-2
Mutant Endosperm of Maize
Authors: Wilson C. M. , Alexander D. E.
Published: October 2006

Three strains of maize heterozygous for the
opaque-2
mutant gene were self-pollinated to produce ears bearing both normal and opaque kernels. The ribonuclease activity of the
opaque-2
endosperm was two to more than four times as high as the activity in the normal endosperm.
Interspecific Brood Parasitism in Blackbirds (Icterinae): a Phylogenetic Perspective
Authors: Lanyon Scott M.
Published: October 2006

An 852-base pair region of the cytochrome-b gene was sequenced for the brood parasitic cowbirds and 20 additional taxa of the New World blackbirds (Icterinae). The goal of the study was to determine (i) whether interspecific brood parasitism is multiply derived within the assemblage and (ii) the nature of the evolutionary transformation between various forms of interspecific brood parasitism. Cladistic analysis of the sequence data indicates that brood parasitism evolved a single time within the Icterinae. The primitive form of interspecific brood parasitism in this assemblage is host-specificity, with host-generality representing the derived condition.
Dimerization of a Specific DNA-Binding Protein on the DNA
Authors: Kim Baek , Little John W.
Published: October 2006

Many specific DNA-binding proteins bind to sites with dyad symmetry, and the bound form of the protein is a dimer. For some proteins, dimers form in solution and bind to DNA. LexA repressor of
Escherichia coli
has been used to test an alternative binding model in which two monomers bind sequentially. This model predicts that a repressor monomer should bind with high specificity to an isolated operator half-site. Monomer binding to a half-site was observed. A second monomer bound to an intact operator far more tightly than the first monomer; this cooperativity arose from protein-protein contacts.
Role of Enzymatic Wall-Softening in Plant Morphogenesis: Hormonal Induction in
Achlya
Authors: Thomas D. des S. , Mullins J. T.
Published: October 2006

Sexual hormone A, which induces antheridial branching in male strains of
Achlya
, also elicits a rise in cellulase. The peak of induced cellulase corresponds in time with the appearance of branches that are the male sexual organ primordia; only those strains that branch in response to the hormone show a concomitant rise in cellulase. The response to the hormone is inhibited by compounds that block protein synthesis, for example,
p
-fluorophenylalanine and puromycin. Vegetative branching, induced by substrates such as casein hydrolysate, is also accompanied by a rise in cellulase.
Eastern North American Archaeology: A Summary
Authors: Griffin James B.
Published: October 2006

The initial occupation of Eastern North America was by small bands of people who gained their livelihood by hunting and gathering. As time passed, the occupants of different regions became increasingly familiar with the available natural resources. The development or introduction of new tools and devices enabled the people to exploit their environments more effectively, until, by Late Archaic times, population size had increased, in terms both of density within a given area and number of people in individual social units.

The initial agricultural productivity aided the culmination of the long cultural traditions in the remarkable productions and practices of the Hopewellian complexes of Middle Woodland times. The major Hopewellian centers reflect the marked change in societal organization and patterns. The costumes of the dead and the manner of their burial clearly reflect individual status differentiations, while artistic creativity is probably to be equated with incipient specialization of labor. Many of the Mississippian societies reached an even more advanced plateau of cultural development, with fortified towns, an organized priesthood, dominant hereditary chiefs, political and military alliances, and a well-developed class system.

The details of the cultural development in Eastern North America are unique, but the general trend may be regarded as a common one in human society, and the patterns of behavior, as analogous to those developed by other peoples in other areas of the Old World and the New.
Regeneration in Crustacean Motoneurons: Evidence for Axonal Fusion
Authors: Hoy Ronald R. , Bittner George D. , Kennedy Donald
Published: October 2006

Crayfish motor axons remain excitable for over 100 days after severance from their central cell bodies, and continue to store and release normal amounts of transmitter substance. Evidence indicates that regeneration occurs by fusion of the central process with its surviving peripheral segment.
Apparatus for Solid-Phase Peptide Synthesis
Authors: Khosla Mahesh C. , Smeby Robert R. , Bumpus F. Merlin
Published: October 2006

The apparatus, designed for solid-phase peptide synthesis, consists of a round-bottom flask, rocked on a wrist-shaker, and fitted with a special dropping funnel and a fritted filter disc embedded within the flask. The dropping funnel is designed to wash down the polymer adhering to the neck of the flask. Solvents are removed through the fritted disc. Entire synthesis, and the removal of peptide from the polymer, are carried out without opening or removing the vessel from the shaker.
Suppressor Selection for Amino Acid Replacements Expected on the Basis of the Genetic Code
Authors: Berger Hillard , Yanofsky Charles
Published: October 2006

In studies with A protein mutants of the tryptophan synthetase of
Escherichia coli
, missense supressors have been used to select for codon changes and corresponding amino acid replacements that are normally unobservable. The technique has permitted the detection of additional amino acid replacements expected on the basis of the genetic code.
Uranium Distribution in Rocks by Fission-Track Registration in Lexan Plastic
Authors: Kleeman J. D. , Lovering J. F.
Published: October 2006

When Lexan plastic is used to register fission tracks from thermal neutron-induced fission of uranium in rocks, a print of the rock texture is formed on the plastic surface after chemical etching. This print allows positive, rapid location of uranium-bearing phases in the rock and accurate determination of uranium abundances.
Human Polymorphonuclear Leukocytes: Demonstration of Microtubules and Effect of Colchicine
Authors: Malawista Stephen E. , Bensch Klaus G.
Published: October 2006

Microtubules are demonstrable in mature human polymorphonuclear leukocytes, even after prolonged incubation in vitro. These organelles are not seen after treatment with colchicine, which has various functional effects on these cells but does not inhibit phagocytosis.
Heritability of Plasma Cholinesterase Activity in Inbred Mouse Strains
Authors: Angel Charles R. , Mahin Dorsey T. , Farris Richard D. , Woodward Kent T. , Yuhas John M. , Storer John B.
Published: October 2006

The activity of cholinesterase was measured in the plasma of 543 mice of both sexes from 23 inbred mouse strains. Differences between strains were highly significant. The heritability of this characteristic was 0.70 in females and 0.67 in males.
The Role of Intuition
Authors: Wilder R. L.
Published: October 2006

"Intuition," as used by the modern mathematician, means an accumulation of attitudes (including beliefs and opinions) derived from experience, both individual and cultural. It is closely associated with mathematical knowledge, which forms the basis of intuition. This knowledge contributes to the growth of intuition and is in turn increased by new conceptual materials suggested by intuition.

The major role of intuition is to provide a conceptual foundation that suggests the directions which new research should take. The opinion of the individual mathematician regarding existence of mathematical concepts (number, geometric notions, and the like) are provided by this intuition; these opinions are frequently so firmly held as to merit the appellation "Platonic." The role of intuition in research is to provide the "educated guess," which may prove to be true or false; but in either case, progress cannot be made without it and even a false guess may lead to progress. Thus intuition also plays a major role in the evolution of mathematical concepts. The advance of mathematical knowledge periodically reveals flaws in cultural intuition; these result in "crises," the solution of which result in a more mature intuition.

The ultimate basis of modern mathematics is thus mathematical intuition. and it is in this sense that the Intuitionistic doctrine of Brouwer and his followers is correct. Modern instructional methods recognize this role of intuition by replacing the "do this, do that" mode of teaching by a "what should be done next?" attitude which appeals to the intuitive background already developed. It is in this way that understanding and appreciation of new mathematical knowledge may be properly instilled in the student.
Separation of Transit of Auxin from Uptake: Average Velocity and Reversible Inhibition by Anaerobic Conditions
Authors: Goldsmith Mary Helen M.
Published: October 2006

An applied pulse of
14
C-indole-3-acetic acid moved down aerobic corn coleoptiles at about 15 millimeters per hour. When sections with a moving pulse were transferred to nitrogen, the rate fell below 2 millimeters per hour. This inhibition was completely reversible; sections returned to air moved the same amount of auxin as untreated aerobic controls.
DDT Residues in an East Coast Estuary: A Case of Biological Concentration of a Persistent Insecticide
Authors: Woodwell George M. , Wurster Charles F. , Isaacson Peter A.
Published: October 2006

DDT residues in the soil of an extensive salt marsh on the south shore of Long Island averaged more than 13 pounds per acre (15 kilograms per hectare); the maximum was 32 pounds per acre (36 kilograms per hectare). A systematic sampling of various organisms from the vicinity showed concentrations of DDT increasing with trophic level through more than three orders of magnitude from 0.04 part per million in plankton to 75 parts per million in a ring-billed gull. Highest concentrations occurred in scavenging and carnivorous fish and birds, although birds had 10 to 100 times more than fish. These concentrations approach those in animals dying from DDT poisoning, which suggests that many natural populations in this area are now being affected, possibly limited, by DDT residues. Similar concentrations have been reported elsewhere in North America.
Drilling on Midway Atoll, Hawaii
Authors: Ladd Harry S. , Tracey Joshua I. , Gross M. Grant
Published: October 2006

Two holes drilled through reef sediments into basalt have established a geologic section through the Miocene. Midway was built above the sea by flows that were weathered and partially truncated in pre-Miocene time. After submergence, volcanic clays were reworked and covered by limestones. Overall submergence was interrupted at least twice by emergence. The limestones have been leached, recrystallized, and partially dolomitized.
Spectrophotometric Cell Sorter
Authors: Kamentsky Louis A. , Melamed Myron R.
Published: October 2006

A new device can physically separate cells of predetermined optical properties from large populations of cells in suspension.
Sediment Distribution on the Mid-Ocean Ridges with Respect to Spreading of the Sea Floor
Authors: Ewing John , Ewing Maurice
Published: October 2006

An abrupt change in sediment thickness between the crests and flanks of the mid-ocean ridges can be interpreted as a major discontinuity in the rates either of spreading of the sea floor or of accumulation of sediment. The preferable interpretation of the data is that the process of spreading of the sea floor is intermittent and that the present cycle of spreading commenced around 10 million years ago. following a long period of quiescence during which most of the observed sediments were deposited.
Carboxy-Terminal Amino Acids of γA and γM Heavy Chains
Authors: Abel Carlos A. , Grey Howard M.
Published: October 2006

The carboxy-terminal amino acids of α- and μ-chains from human immunoglobulins and α-chains from mouse immunoglobulins have been determined by carboxypeptidase digestion and hydrazinolysis. The data suggest the following carboxy-terminal sequences: human μ: Ala-Gly-Thr-Cys-TyrCOOH; human α: Thr-Cys-TyrCOOH; murine α: (Ileu, Cys)-TyrCOOH.
RNA and DNA Synthesis in Developing Eggs of the Milkweed Bug,
Oncopeltus fasciatus
(Dallas)
Authors: Harris Stephen E. , Forrest Hugh S.
Published: October 2006

Ribosomal RNA synthesis in developing eggs of the milkweed bug,
Oncopeltus fasciatus
(Dallas), is turned on at gastrulation and is essentially turned off when organogenesis begins about 72 hours later. The pattern for DNA synthesis is similar although less pronounced.
Antimalarial Activity of Tetrahydrohomopteroic Acid
Authors: Kisliuk R. L. , Friedkin M. , Schmidt L. H. , Rossan R. N.
Published: October 2006

Tetrahydrohomopteroic acid, an analog of tetrahydrofolic acid, shows antimalarial activity against
Plasmodium cynomolgi
and a pyrimethamine-resistant variant of this organism.
Centriole Duplication in Lysates of
Spisula solidissima
Oocytes
Authors: Palazzo Robert E. , Vaisberg Eugeni , Cole Richard W. , Rieder Conly L.
Published: October 2006

A cell-free system has been developed that executes centriole duplication. Surf clam (
Spisula solidissima
) oocytes, arrested at late prophase of meiosis I, do not contain centrioles, centrosomes, or asters. Serial section high-voltage electron microscopy (HVEM) of asters and spindles isolated from potassium chloride-activated oocytes indicates that within 4 minutes oocytes assemble a single centriole that is duplicated by 15 minutes when assembly of the first meiotic spindle is complete. A mixture of lysates from unactivated oocytes and potassium chloride-activated oocytes induces centriole formation and duplication. Astral microtubule content in these lysate mixtures increases with time.
Romeriscus
, the Oldest Known Reptile
Authors: Baird Donald , Carroll Robert L.
Published: October 2006

The description of
Romeriscus
, a new genus of limnoscelid reptile, is based on a partial skeleton from the Early Pennsylvanian (Westphalian A) of Nova Scotia. Although it is the earliest and most primitive reptile yet known, it is probably already too late and too specialized to be ancestral to the more advanced Carboniferous and Permian captorhinomorphs and pelycosaurs.
Adenovirus Endocarditis in Mice
Authors: Blailock Z. R. , Rabin E. R. , Melnick J. L.
Published: October 2006

Viral endocarditis developed in 24 percent of 50 newborn mice 6 to 8 days after intraperitoneal inoculation with murine adenovirus. Typical adenovirus intranuclear inclusions were seen in heart-valve lesions, and high titers of virus were recovered from heart tissue. Furthermore, adenovirions were directly visualized by electron microscopy within endothelial cells and fibroblasts of the heart valves.
Aminoacidemias: Effects on Maze Performance and Cerebral Serotonin
Authors: McKean Charles M. , Schanberg Saul M. , Giarman Nicholas J.
Published: October 2006

The feeding of high dietary supplements of L-phenylalanine (7 percent) and L-leucine (7 percent) to weanling rats is associated with poor performance in a multiple-T, water-escape maze. Supplements high in L-tryptophan (5 percent), on the other hand, result in maze performance which is superior to that of controls. Adding 5 percent tryptophan to the high-phenylalanine diet reverses the behavioral deficit. The quality of maze performance correlated with the cerebral content of serotonin.
Implications for Geophysics of the Precise Measurement of the Earth's Rotation
Authors: MacDonald Gordon J. F.
Published: October 2006

A radio interferometer could yield an error on the order of 10
-9
second at the semidiurnal frequency. With errors of this magnitude, yearly changes in the rate at which the earth's rotation is slowing down could be determined. The proposed interferometer could also yield significant improvements in the determination of the Love number
k
and its variation with frequency, and in the changes in angular momentum of the atmosphere for periods greater than 1 week.
High-Conductivity Solid Electrolytes: MAg
4
I
5
Authors: Owens Boone B. , Argue Gary R.
Published: October 2006

The solid electrolytes MAg
4
I
5
, where M may be potassium, rubidium, or ammonium, have an ionic conductivity of 0.2 (ohm cm)
-1
at 20°C. Although pure CsAg
4
I
5
does not form, partial substitution of cesium into the M position was obtained. The high-conducting phases of KAg
4
I
5
and RbAg
4
I
5
may be quenched to low temperatures, where they transform to resistive phases at -136° and -155°C, respectively.
Chromosomal Abnormalities in Leukocytes from LSD-25 Users
Authors: Irwin Samuel , Egozcue Jose
Published: October 2006

A significant increase of chromosomal abnormalities was found in leukocytes from LSD-25 users (six out of eight) compared to nonuser controls (one out of nine). The two LSD-25 users showing no damage reported the lowest estimated average dose. The subjects whose cells showed damage were tested between 1 day and 6 months after their last LSD-25 dose.
Membranes in Polyribosome Formation by Rabbit Reticulocytes
Authors: Freedman Michael L. , Hori Makoto , Rabinovitz Marco
Published: October 2006

When rabbit reticulocytes are incubated with
n
-butanol, an agent disruptive to the structure and function of cellular membranes, there is a rapid disaggregation of the polyribosomes. Reaggregation is promoted when the
n
-butanol is diluted below a critical concentration or when the cells are washed free of the alcohol and the incubation is continued. Neither disaggregation nor regeneration will occur in the absence of protein synthesis. These observations suggest that integrity of the reticulocyte membrane is necessary for the attachment of ribosomes to messenger RNA and for the formation of polyribosomes.
Resonance Rotation of Venus
Authors: Shapiro Irwin I.
Published: October 2006

Combination of two types of radar data shows the orbital plane and equator of Venus to be inclined by less than 2 degrees, and the sidereal rotation period to be 243.09 ± 0.18 days (retrograde)—remarkably close to the 243.16-day period for which the spin would be in resonance with the relative orbital motions of Earth and Venus. In this resonance, Venus would make, on average, four axial rotations as seen by an Earth observer between successive close approaches of the two planets. Estimates of the instantaneous spin period, accurate within about 0.01 day, would provide important information on the difference of Venus's equatorial moments of inertia, on their orientation, and on the magnitude of the tidal torque exerted on Venus by the sun.
Autosomal Phosphogluconic Dehydrogenase Polymorphism in the Cat (
Felis catus
L.)
Authors: Thuline H. C. , Morrow Anne C. , Norby D. E. , Motulsky A. G.
Published: October 2006

Three patterns of 6-phosphogluconic dehydrogenase activity were obtained by starch-gel electrophoresis of blood from domestic cats. Genetic analysis indicates control of these patterns by a pair of alleles at an autosomal locus. Presence of three enzymatically active bands in heterozygotes and of single bands in homozygotes is compatible with at least a dimeric structure for the enzyme.
Sodium-Potassium Adenosine Triphosphatase: Acyl Phosphate "Intermediate" Shown to be L-Glutamyl-γ-Phosphate
Authors: Kahlenberg Arthur , Galsworthy Peter R. , Hokin Lowell E.
Published: October 2006

Peptides obtained from pepsin digestion of the phosphorylated and nonphosphorylated forms of a preparation of brain microsomal sodium-potassium-activated adenosine triphosphatase were treated at p
H
5.4 with
N
-(
n
-propyl-2,3-
3
H)hydroxylamine of high specific activity, then separated by column chromatography, and further digested with pronase. A compound isolated in higher amounts from the phosphorylated enzyme than from the nonphosphorylated enzyme migrated with authentic L-glutamyl-γ-propylhydroxamate in four chromatographic systems and on electrophoresis on paper at three different
p
H's. The acyl phosphate "intermediate" in the phosphorylated form of the adenosine-triphosphatase therefore appears to be an L-glutamyl-γ-phosphate residue.
Improved in vitro Survival of Normal, Functional Spleen Cells
Authors: Mohit Behzad , Sato Gordon H.
Published: October 2006

An enrichment method for improving the viability of monolayers of normal mouse spleen cells is described. These cells are capable of saving lethally x-irradiated recipient mice from death, presumably by proliferating and differentiating into mature blood cells.
Infrared Stars
Authors: Johnson Harold L.
Published: October 2006

Our searches for very cool stars have revealed three kinds of objects: very cool Mira stars, perhaps cooler than any of this type previously known; extremely dense interstellar clouds, more dense than any known heretofore; and, probably, cool circumstellar clouds that may be planetary systems in an early stage of formation.
Collagen-Like Fragments: Excretion in Urine of Patients with Paget's Disease of Bone
Authors: Krane Stephen M. , Muñoz Alberto J. , Harris Edward D.
Published: October 2006

Patients with Paget's disease of bone excrete, in the urine, polypeptides that have amino acid composition and other properties resembling those of fragments of collagen. The pattern of isotope incorporation in vivo suggests that these fragments are derived from collagen that has been synthesized and rapidly degraded, or that they are rapidly synthesized but not incorporated into tropocollagen molecules.
Andesitic Volcanism and Seismicity around the Pacific
Authors: Dickinson William R. , Hatherton Trevor
Published: October 2006

Circum-Pacific andesites, with associated basalts and dacites, are erupted from linear island arcs and marginal continental ranges whose ocean-side borders coincide approximately with the continent-side boundaries of belts of shallow seismicity that parallel adjacent trenches. The lines of active volcanoes stand above elongate subcrustal regions delineated by the intersection of inclined Benioff seismic zones and the subhorizontal Gutenberg low-velocity zone. Close correlation between content of potash in erupted lavas and vertical depth to the Benioff zone suggests that andesitic volcanism has its origins in the mantle where magmas are generated by events associated with earthquakes of intermediate focal depth.
Mating Behavior: Facilitation in the Female Rat after Cortical Application of Potassium Chloride
Authors: Clemens Lynwood G. , Wallen Kim , Gorski Roger A.
Published: October 2006

Mating behavior in ovariectomized female rats treated with estrogen can be greatly enhanced by subcutaneous injections of progesterone. Application of potassium chloride to the cortex of females previously treated with estrogen can also induce greatly increased sexual receptivity as indicated by the lordosis response. This facilitation of mating behavior by a treatment known to cause functional decortication suggests that mechanisms mediating female mating behavior are under tonic inhibition by an inhibitory system which involves the cerebral cortex.
Vertebrate Regeneration System: Culture in vitro
Authors: Simpson S. B. , Cox Prentiss G.
Published: October 2006

With standard tissue-culture techniques and media, various components of the lizard tail regenerate have been maintained in culture for 8 months. Differentiation of two cell types, melanophores and striated muscle, has been obtained. Myoblast proliferation and fusion can be selectively controlled by altering the culture medium.
Tornadoes: Mechanism and Control
Authors: Colgate Stirling A.
Published: October 2006

If electrical energy is invoked to account for the high velocity of tornadoes, hydrodynamics restricts the possible mechanisms of energy exchange. In particular, the vortex is driven by a line sink of electrically heated air that must extend at least 5 kilometers high. In those rare cases where heroic measures may be justified to protect a city in the path of a major tornado, some possible control measures are discussed in terms of the electrical heating mechanism.
Histocompatibility Antigen Transfer in Utero: Tolerance in Progeny and Sensitization in Mother
Authors: Tai Chiaki , Halasz Nicholas A.
Published: October 2006

Subcellular antigens obtained from donor spleen and kidney were administered to pregnant rabbits treated with hyaluronidase. Partial immunological tolerance to the donor was thus induced in the fetuses during the adaptive phase. The duration of tolerance was proportional to the total dose of antigen administered to the mother. Maternal sensitization to the offspring was noted in all rabbits giving birth to partially tolerant progeny.
Sodium Transport: Inhibitory Factor in Sweat of Patients with Cystic Fibrosis
Authors: Mangos John A. , McSherry Nona R.
Published: October 2006

A factor inhibitory to sodium transport exists in the sweat of patients with cystic fibrosis of the pancreas. When the duct system of the rat parotid was perfused with sweat from patients, marked inhibition of sodium reabsorption was observed. Perfusion with sweat from normal subjects caused no change in sodium reabsorption. The factor thus demonstrated may be responsible for the increased sodium concentrations in the sweat of patients with cystic fibrosis.