bluuebunny/crossref_metadata_2025 huggingface dataset:
Lactate Dehydrogenase in Pigeon Testes: Genetic Control by Three Loci
Authors: Zinkham William H. , Blanco Antonio , Kupchyk Luba
Published: October 2006

Homogenates of pigeon testes show three types of lactate dehydrogenase isozyme patterns. Recombination of the polypeptide subunits of the dehydrogenase in mixtures of the different types, and the distribution of the three isozyme patterns in six different pigeon populations demonstrated that lactate dehydrogenase synthesis in pigeon testes is under the control of three distinct loci, A, B, and C.
Geometry of Bermuda Calcareous Dune Cross-Bedding
Authors: Mackenzie Fred T.
Published: October 2006

Bermuda wind-blown limesands are lobate-shaped bodies composed internally of leeward foreset strata which dip at 30 to 35 degrees and windward strata which dip at 10 to 15 degrees in an opposite direction. The foreset beds are convex upward. This convex upward cross-stratification is preserved because of the early stabilization of the eolian calcareous sand due to surface cementation by percolating rain water.
Petroleum Hydrocarbons: Generation from Fatty Acid
Authors: Jurg J. W. , Eisma E.
Published: October 2006

In the presence or absence of water, behenic acid generates hydrocarbons during heating at 200°C with bentonite. Without water the ratio of isobutane or isopentane to normal butane or normal pentane is much higher than with water. Besides C
21
and lower n-alkanes, n-alkanes with 22 to 34 carbon atoms are also formed.
Garnet Ratios and Provenance in The Glacial Drift of Western New York
Authors: Connally G. Gordon
Published: October 2006

The ratio of purple to red garnet identifies drift provenance. Low ratios indicate glacier flow from the central Adirondacks. Ratios of 1.4 or greater indicate flow from Canada, by way of the St. Lawrence lowland. The heavy mineral assemblages were evidently undiluted by local sources in western New York.
Estrous Synchrony in Mice: Alteration by Exposure to Male Urine
Authors: Marsden Halsey M. , Bronson F. H.
Published: October 2006

Exposure of grouped, virgin female laboratory mice to urine from male mice for 2 days prior to pairing significantly altered the expected pattern of estrous synchrony. A higher proportion of mice exposed to male urine attained estrus during the 2 days after pairing than did mice exposed to female urine or control mice.
Plasmodium berghei
: Cyclical Transmissions by Experimentally Infected
Anopheles quadrimaculatus
Authors: Yoeli Meir , Most Harry , Bone Georges
Published: October 2006

A number of strains of
Plasmodium berghei
were isolated from sporozoites of
Anopheles dureni
. Laboratory-bred
Anopheles quadrimaculatus
fed on carriers of the newly isolated strains showed overwhelming midgut infections and moderate or mild salivary gland infections. Successive cyclic transmissions by the bite of experimentally infected A. quadrimaculatus in laboratorybred tree rats (
Thamnomys surdaster
) were carried out.
Attention, Vigilance, and Cortical Evoked-Potentials in Humans
Authors: Haider Manfred , Spong Paul , Lindsley Donald B.
Published: October 2006

Computer-averaged potentials evoked from the cortex were recorded to nonsignal stimuli and to randomly interspersed signal stimuli requiring detection and response during prolonged visual vigilance. As detection efficiency diminished over time, the amplitude of evoked responses to nonsignal stimuli decreased and latency increased. Fluctuations in vigilance (attentiveness) during the course of the task also were accompanied by corresponding changes in evoked-potentials to nonsignal stimuli. More specific lapses of attention, revealed by detection failures, resulted in average evoked-responses of lower amplitude to missed as compared with detected signals.
Recent High Relative Sea Level Stand near Recife, Brazil
Authors: van Andel Tjeerd H. , Laborel Jacques
Published: October 2006

Radiocarbon dates for Vermetidae limestone from the edge of the Brazilian Shield at Cape San Agostinho, Brazil, indicate sea level stands of up to 2.60 meters above the present position, 3660, 2790, and 1190 years ago. Accurate determination of relative sea level is possible because of the well-defined habitat of the fossils dated.
Differential Estimation of Gamma-butyrolactone and Gamma-hydroxybutyric Acid in Rat Blood and Brain
Authors: Giarman Nicholas J. , Roth Robert H.
Published: October 2006

A sensitive and specific gas chromatographic technique for estimating concentrations of the anesthetic adjuvants, γ-butyrolactone and γ-hydroxybutyrate, in tissues has been developed. These substances do not appear to occur endogenously in either the blood or the brain of common laboratory animals. The onset and duration of anesthesia caused by the administration of either compound is correlated with the concentration of γ-hydroxybutyrate in the brain, rather than with that of the corresponding lactone.
Behavior in
Hydra
: Inhibition of the Contraction Responses of
Hydra pirardi
Authors: Rushforth Norman B. , Krohn Ivan T. , Brown Loma K.
Published: October 2006

Hydra pirardi
contracts spontaneously and in response to external stimuli of light and mechanical agitation. Inhibition of these contractions occurs when the animal feeds on
Artemia salina
or when reduced glutathione is present in the environment. Such inhibition demonstrates the control of one receptor-effector system by another in hydra.
Redifferentiation of Connective Tissue Cells in Serial Culture
Authors: Priest Robert E. , Priest Jean H.
Published: October 2006

When cell cultures are initiated from aortic connective tissue of rats and maintained as monolayers on glass, the differentiated property of collagen production disappears. However, these same cells, when placed in diffusion chambers in the peritoneal cavities of other rats, produce collagen, as indicated both morphologically and by the accumulation of hydroxyproline within the chambers.
Auditory Flutter-Driving of Visual Flicker
Authors: Shipley T.
Published: October 2006

Changes in the physical flutter rate of a clicking sound induce simultaneous changes in the apparent flicker rate of a flashing light. For example, for one observer a flicker with a frequency of 10 cycles per second was driven downward to as low as 7 cycles per second and upward to as high as 22 cycles per second by changing the rate of initially synchronous auditory clicks. The reverse does not occur—changes in the flicker rate do not induce changes in apparent flutter rates.
Planaria: Memory Transfer through Cannibalism Reexamined
Authors: Hartry Arlene L. , Keith-Lee Patricia , Morton William D.
Published: October 2006

Planaria which have cannibalized untrained planaria exposed to photic stimuli only, handling only, or previous conditioning, all require significantly fewer trials in a conditioning situation than naive planaria.
Uric Acid in the Reproductive System of Males of the Cockroach
Blattella germanica
Authors: Roth Louis M. , Dateo George P.
Published: October 2006

Uric acid is stored in the utriculi majores of the accessory sex glands of the German cockroach. Most of the uric acid is eliminated during copulation by being poured over the spermatophore. Mating appears to be an important means of excretion in this cockroach.
Homocystinuria due to Cystathionine Synthetase Deficiency: The Mode of Inheritance
Authors: Finkelstein James D. , Mudd S. Harvey , Irreverre Filadelfo , Laster Leonard
Published: October 2006

Deficiency of cystathionine synthetase activity results in the clinical syndrome of homocystinuria. In both parents of a patient with homocystinuria, the hepatic cystathionine synthetase activity was 40 percent of that in unrelated control patients. These findings demonstrate that the metabolic error is inherited and suggest that the parents, although clinically normal, represent the heterozygous state. A second case of homocystinuria also is shown to be associated with cystathionine synthetase deficiency.
Allosteric Properties of Glutamate Dehydrogenases from Different Sources
Authors: Talal Norman , Tomkins Gordon M.
Published: October 2006

The structure and allosteric properties of glutamate dehydrogenases from different sources have been studied by immunologic means. Despite structural differences detected by electrophoretic mobility and antigenicity, all the vertebrate enzymes responded similarly to allosteric modification. Bacterial glutamate dehydrogenase was immunologically unrelated to the vertebrate enzymes and did not respond to allosteric regulation.
Protein Structure Relationships Revealed by Mutational Analysis
Authors: Yanofsky Charles , Horn Virginia , Thorpe Deanna
Published: October 2006

Studies of tryptophan synthetase A-protein mutants have shown a structural relationship between the positions of amino acid changes associated with forward mutations and second-site reverse mutations.
Calotropin, a Cytotoxic Principle Isolated from
Asclepias curassavica
L.
Authors: Kupchan S. Morris , Knox John R. , Kelsey John E. , Renauld J. A. Saenz
Published: October 2006

An alcoholic extract of
Asclepias curassavica
L., a plant widely used in folk medicine for treating cancer and warts, shows cytotoxic activity when tested in vitro against cells derived from human carcinoma of the nasopharynx. Systematic fractionation of the extract has led to isolation and characterization of calotropin as a cytotoxic principle. Calotropin is similar in structure to two cardiac glycosides recently shown to be responsible for the cytotoxicity of
Apocynum cannabinum
L.
Callanish, a Scottish Stonehenge
Authors: Hawkins Gerald S.
Published: October 2006

On the basis of the stone record it appears that the Callanish people were as precise as the Stonehengers in setting up their megalithic structure, but not as scientifically advanced. Callanish is, however, a structure that could have been used much as Stonehenge was. It would be interesting to obtain a date, by the radiocarbon method, for the peat in the area of Callanish, to determine how much older, or more recent, than Stonehenge this structure is. Perhaps the knowledge gained at Callanish was later used in the design of Stonehenge.
Explosion Seismology
Authors: Carpenter E. W.
Published: October 2006

I have tried to describe some current research trends in seismology which are specifically directed toward solving the problem of detecting, locating, and identifying underground nuclear explosions. Attention has been directed specifically toward problems which arise in efforts to obtain information at distances in excess of 2500 kilometers. The main scientific advantage which accrues from working at such distances is that the seismic signals suffer minimal distortion by the geological complexities of the earth. Extrapolation of the data to the question of an international test ban is not within the scope of this article. Suffice it to note that all of the parameters must, in the final resort, be resolved in terms of probabilities. In some cases the seismological probabilities can be estimated with reasonable degrees of accuracy, but the future of the test ban question depends not only on seismology but on such questions as inspection and what probabilities are acceptable.
Experimental Phenylketonuria in Infant Monkeys
Authors: Waisman Harry A. , Harlow Harry F.
Published: October 2006

Experimental phenylketonuria can be produced in infant monkeys by feeding excessive quantities of L-phenylalanine soon after birth. Both the phenylketonuric monkey and the phenylketonuric human patient have elevated plasma levels of phenylalanine, and monkey and human excrete almost the same phenylalanine metabolites in the urine. Grand-mal convulsions, observed in some children with phenylketonuria, were also observed in the experimental animals. The biochemical evidence was supported by the learning data. The observed slowness in adapting to testing procedures, or even failure to adapt, and the inadequate performance suggest an intellectual deficit.
Neurosecretory Processes Extending into Third Ventricle: Secretory or Sensory?
Authors: Smoller Carolyn G.
Published: October 2006

"Dendrites" projecting into the third ventricle from hypothalamic neurosecretory neurons of the Pacific tree frog,
Hyla regilla
, appear to be morphologically equipped to serve both secretory and sensory functions. These cell processes contain elementary neurosecretory granules, Golgi membranes, mitochondria, and endoplasmic reticulum, suggesting synthesis and possibly release of hormonal material. Each "dendrite" is provided with a single cilium which has an accessory centriole and a striated rootlet.
Erythropoiesis in the Chick Embryo: The Role of Endoderm
Authors: Wilt Fred H.
Published: October 2006

The endoderm can be separated from the ectomesoderm of the area vasculosa of the early chick embryo. The development of the separated germ layers in organ cultures shows that the endoderm is necessary for the normal formation of blood islands by mesodermal cells. In the absence of endoderm the mesodermal cells undergo erythropoiesis in dispersed groups of cells but do not form endothelium.
Kink-Bands: Shock Deformation of Biotite Resulting from a Nuclear Explosion
Authors: Cummings David
Published: October 2006

Microscopic examination of granodiorite samples from the shock region around a nuclear explosion reveals sharply folded lens-shaped zones (kink-bands) in the mineral biotite. Fifty percent of these zones are oriented approximately 90° to the direction of shock-wave propagation, but other zones are symmetrically concentrated at shear angles of 50° and 70° to the direction of shock-wave propagation.
Cell Proliferation in Hydra: An Autoradiographic Approach
Authors: Campbell Richard D.
Published: October 2006

Hydra cells take up substantial amounts of tritiated thymidine if the label is injected into an animal's gastric cavity shortly after feeding. Autoradiographic analysis shows that the isotope becomes incorporated into cell nuclei. The distribution of labeled nuclei probably represents the pattern of cell proliferation and is similar to the distribution of mitotic figures in histological preparations. The data show that cell proliferation is distributed along the body column and that there is no localized growth zone.
Genetic Mosaicism in Adult Mice of Quadriparental Lineage
Authors: Mintz Beatrice
Published: October 2006

Genetic mosaic mice can be produced by aggregating, during cleavage stages, the blastomeres of two embryos of different genotype into a single cluster, and by transferring the developing aggregates to the uterus of a surrogate mother. Substantial numbers of such composite embryos survive past birth. Among the living adult mosaic mice are individuals within which cells of markedly different immunogenetic constitution coexist. Through the incorporation of appropriate genetic markers into mosaics, many new possibilities now present themselves for analysis of biological problems during embryonic as well as adult life.
Growth of Rats Fed on
Opaque-2
Maize
Authors: Mertz Edwin T. , Veron Olivia A. , Bates Lynn S. , Nelson Oliver E.
Published: October 2006

Six weanling male rats were fed a diet containing 90 percent
opaque-2
maize for 28 days. The average gain in weight was 97 grams. In control rats fed on a standard hybrid maize the average gain was 27 grams. This confirms results of a previous feeding test on rats and demonstrates the superior quality of the proteins in
opaque-2
mutant endosperm.
Human Transferrins C and D
1
: Chemical Difference in a Peptide
Authors: Wang An-Chuan , Sutton H. Eldon
Published: October 2006

Peptide analyses have been carried out for chymotryptic digests of transferrin C and transferrin D
1
. There is a difference in one peptide, and amino acid analyses indicate that an aspartic acid residue in transferrin C is replaced probably by a glycine residue in transferrin D
1
.
Dengue Type 2 Virus in Naturally Infected
Aedes albopictus
Mosquitoes in Singapore
Authors: Rudnick A. , Chan Y. C.
Published: October 2006

A strain of dengue type 2 virus has been isolated from
Aedes albopictus
collected in Singapore. This is the first report of a natural isolation of dengue virus from this species, which has long been suspected as a vector in nature.
Saturn's Ring and the Satellites of Jupiter: Interpretations of Infrared Spectra
Authors: Owen Tobias
Published: October 2006

Infrared spectra of Saturn's ring correspond closely with the reflection spectrum of water ice. This result supports Kuiper's suggestion for the composition of the ring. The absence of the strong absorption at 8873 Å in spectra of Io, Ganymede, and Callisto leads to a new upper limit for the abundance of methane in possible atmospheres of these satellites.
Nuclear Mitochondria?
Authors: Brandes David , Schofield Brian Henry , Anton Elsa
Published: October 2006

Recognizable mitochondria were detected in the nucleus of a leukemic cell. It is suggested that passage through enlarged nuclear pores, incorporation within a pinched off invagination, or inclusion within the nuclear envelope at telophase may have been responsible for this unusual event.
Role of Orbital Cortex in Regulation of Thalamocortical Electrical Activity
Authors: Velasco Marcos , Lindsley Donald B.
Published: October 2006

The orbital region of the cortex in the cat is essential to the occurrence of spontaneous spindle bursts and thalamically induced recruiting responses, observed in both cortex and thalamus. Ablations of the entire dorsal convexity, and of the mesial and cingulate regions of the cortex, failed to interfere with the spindle bursts and recruiting responses, whereas ablations confined to the orbital cortex alone abolished completely these potentials in the cortex and thalamus. Therefore, the orbital cortex appears to be the only region of the neocortex to play a crucial role in the regulation of thalamocortical synchronizing and integrating functions. These functions are believed to be associated with a nonspecific system governing internal inhibition which manifests itself in inattention, drowsiness, and sleep.
Actinomycin D: Inhibition of Protein Synthesis Unrelated to Effect on Template RNA Synthesis
Authors: Honig George R. , Rabinovitz Marco
Published: October 2006

Incubation of sarcoma-37 ascites cells in vitro with actinomycin D resulted in inhibition of synthesis of nuclear and cytoplasmic proteins. The overall inhibition could be prevented or relieved by glucose; it is thus unrelated to breakdown of template RNA.
Evidence from 18
S
Ribosomal RNA Sequences that Lampreys and Hagfishes form a Natural Group
Authors: Stock David W. , Whitt Gregory S.
Published: October 2006

Lampreys and hagfishes (cyclostomes) traditionally were considered to be a natural (monophyletic) group. Recently, the consensus of opinion, based largely on morphological analyses, has shifted to a view that lampreys are more closely related to jawed vertebrates (gnathostomes) than to hagfishes. Phylogenetic comparisons of 18
S
ribosomal RNA sequences from two hagfishes, two lampreys, a tunicate, a lancelet, and a number of gnathostomes support the monophyly of the cyclostomes. These data force a reassessment of several features of early vertebrate evolution.
Nonuniform Cooling of the Eclipsed Moon: A Listing of Thirty Prominent Anomalies
Authors: Shorthill R. W. , Saari J. M.
Published: October 2006

Infrared scanning during a total eclipse has revealed hundreds of hot spots, many identified with craters smaller than the detector resolution. Areal corrections show that some of these features may have the thermal properties of bare rock. Correlation of thermal response with albedo and radar reflectivity shows discrepancies. There is a concentration of hot spots in Mare Tranquillitatis.
Magnetic Anomalies over a Young Oceanic Ridge off Vancouver Island
Authors: Vine F. J. , Wilson J. Tuzo
Published: October 2006

The recent speculation that the magnetic anomalies observed over oceanic ridges might be explained in terms of ocean-floor spreading and periodic reversals of the earth's magnetic field may now be reexamined in the light of suggested reversals during the past 4 million years and the newly described Juan de Fuca Ridge.
Complement Fixation on Cell Surfaces by 19
S
and 7
S
Antibodies
Authors: Borsos Tibor , Rapp Herbert J.
Published: October 2006

The mechanism of complement fixation on cell surfaces by whole antiserums, and by 19
S
and 7
S
fractions has been studied with a new complement-fixation test. This test is based on the fixation and transfer of the activated first component of complement (C′1a). We have concluded that a single molecule of 19
S
antibody in combination with antigen at the cell surface is sufficient to bind one molecule of C′1a. For 7
S
antibodies at least two molecules in close proximity at the cell surface are required to fix one molecule of C′1a.
Soudan Formation: Organic Extracts of Early Precambrian Rocks
Authors: Meinschein W. G.
Published: October 2006

Biological-type alkanes are present in rocks of the Soudan formation that are more than 2.7 × 10
9
years old, but evidence of life in Soudan times is marginal. The distributional patterns of the alkanes from various regions in the Soudan indicate an indigenous origin of these compounds. Isotopic analyses do not confirm the compositional analyses.
Microsaccades and the Velocity-Amplitude Relationship for Saccadic Eye Movements
Authors: Zuber B. L. , Stark L. , Cook G.
Published: October 2006

The maximum velocities of microsaccades (flicks) are an increasing function of amplitude of movement. Measured velocities fall on the extrapolation of the curve of maximum velocity versus amplitude for voluntary saccades and involuntary corrective saccades. Hence all these movements are produced by a common physiological system, or the characteristics of the movements are determined by a single dynamically limiting element.
Diapause Induction in
Daphnia
Requires Two Stimuli
Authors: Stross Raymond G. , Hill Jeanne C.
Published: October 2006

Short-day photoperiods in conjunction with a second stimulus were required to induce sexual reproduction (and diapause) in an autumnally diapausing strain of
Daphnia pulex
. The second stimulus was associated with the unalkalized portion of a small lake and with density of the population in laboratory cultures. Diapause was induced at 12° and 19°C.
Second Mutant Gene Affecting the Amino Acid Pattern of Maize Endosperm Proteins
Authors: Nelson Oliver E. , Mertz Edwin T. , Bates Lynn S.
Published: October 2006

The mutant
floury-2
results in the production of maize endosperm proteins with an altered amino acid pattern. The lysine concentration is high, approximately equal to that in mutant
opaque-2
, and the methionine concentration is higher than in any other stock tested. Other mutants of similar phenotype,
opaque-1
,
floury-1
, and
soft-starch
do not cause major changes in amino acid pattern.
Food Imprinting in the Snapping Turtle,
Chelydra serpentina
Authors: Burghardt Gordon M. , Hess Eckhard H.
Published: October 2006

Three groups of hatchling snapping turtles, totaling 20, were fed either meat, fish, or worms. When they were tested for preference after 12 daily feedings, each preferred the diet to which it was accustomed. After 12 more days of eating a different food, each still preferred its original diet. A form of imprinting may be operative in the feeding behavior of this species.
Plasma Membranes: Phospholipid and Sterol Content
Authors: Ashworth L. A. E. , Green C.
Published: October 2006

The molar ratios of sterol to phospholipid in plasma membranes of five different types of rat cells range from 0.24 to 1.32. The composition of the plasma membrane of a cell has no fixed relation to that of the mitochondria. Thus the structure of cellular membranes shows both tissue and functional specificity.
Manganese Pavements on the Blake Plateau
Authors: Pratt Richard M. , McFarlin Peter F.
Published: October 2006

Dredge samples and photographs from the Blake Plateau, off the southeast coast of the United States, indicate that a layer of manganese oxide forms pavement that may be continuous over an area of about 5000 square kilometers. The manganese pavement grades into round manganese nodules to the south and east and into phosphate nodules to the west. The Gulf Stream probably maintains a very unusual environment that prohibits deposition of clastic sediment and permits accretion of manganese pavements.
Controlling Cardiac Chaos
Authors: Garfinkel Alan , Spano Mark L. , Ditto William L. , Weiss James N.
Published: October 2006

The extreme sensitivity to initial conditions that chaotic systems display makes them unstable and unpredictable. Yet that same sensitivity also makes them highly susceptible to control, provided that the developing chaos can be analyzed in real time and that analysis is then used to make small control interventions. This strategy has been used here to stabilize cardiac arrhythmias induced by the drug ouabain in rabbit ventricle. By administering electrical stimuli to the heart at irregular times determined by chaos theory, the arrhythmia was converted to periodic beating.
Cyanide Intoxication: Protection with Oxygen
Authors: Way James L. , Gibbon Stanley L. , Sheehy Maureen
Published: October 2006

Prophylactic protection against cyanide intoxication in mice can be enhanced by the administration of oxygen, especially when it is used in combination with the conventional cyanide antidotes, sodium nitrite and sodium thiosulfate. The LD
50
values were compared in groups of mice premedicated with sodium thiosulfate or sodium nitrite, or both, in air and in oxygen. These results indicate that oxygen alone provides only minimal protection. Although oxygen enhances the protective effect of sodium thiosulfate to a minor degree, it does not enhance the protection of sodium nitrite at all; and yet, it potentiates the effectiveness of a combination of these two antagonists against cyanide intoxication.
Blood Pressure Responses of Wild Giraffes Studied by Radio Telemetry
Authors: Van Citters Robert L. , Kemper William S. , Franklin Dean L.
Published: October 2006

Blood pressure was telemetered from transducers chronically implanted in the carotid arteries of two adult, wild, male giraffes captured and released near Kiboko, Kenya. Cerebral perfusion pressure ranged from 280/180 mm-Hg while the animal was lying with its head on the ground to 125/75 mm-Hg when it was standing erect; it varied between these levels during spontaneous activity such as walking, grazing, and running.
Superconductivity of Alpha-Uranium and the Role of 5
f
Electrons
Authors: Geballe T. H. , Matthias B. T. , Andres K. , Fisher E. S. , Smith T. F. , Zachariasen W. H.
Published: October 2006

A much sharper and lower superconducting transition has been found for α-uranium than any reported previously. A model that explains the unusual volume dependence of α-uranium below 43°K and the unusual pressure dependence of its superconducting transition temperature is presented.
Strontium Isotopes in Deep-Sea Sediments
Authors: Dasch E. Julius , Hills F. Allan , Turekian Karl K.
Published: October 2006

Recent deep-sea sediments, leached of carbonate, have Sr
87
: Sr
86
ratios ranging from 0.7044 to 0.7394. Strontium in the detrital sediment has not equilibrated isotopically with seawater strontium. Amounts of strontium-bearing authigenic material in the clay-mineral assemblage are not great enough to mask strontium-isotope ratios inherited from source areas.
Dominant Hemispherectomy: Preliminary Report on Neuropsychological Sequelae
Authors: Smith Aaron , Burklund C. W.
Published: October 2006

The first reported case of continuing survival 6 months after left hemispherectomy for glioma in a right-handed adult shows diminishing psychological impairment. Different degrees of initial impairment and in subsequent recovery of propositional speech, verbal comprehension, reading, writing, and other functions indicate quantitative rather than-qualitative differences in adult left- and right-hemispheric functions.
Hypertrophy versus Hyperplasia
Authors: Goss Richard J.
Published: October 2006

Although all tissues and organs of the body are normally subject to the growth-regulating influences of functional demands, some are potentially capable of unlimited growth while others are not. This depends on whether hyperplasia of their functional units ceases prior to maturity or can continue throughout life. In the former case, further growth is limited by the extent to which hypertrophy can enhance physiological efficiency. Some of the body's most vitally essential organs (heart, brain, kidney, lung) lack the ability to make additional structural units in the adult and are therefore handicapped in compensating for the depreciations of advancing age. Theoretically, at least, other organs (glands, renewing tissues) possess unlimited powers of regeneration because they never lose the capacity (latent or expressed) for hyperplasia.

There is a strategy in the way growth mechanisms have evolved. It may be significant that the so-called "hypertrophic" organs lose the capability for hyperplasia, because not to do so might jeopardize their growth regulation. If size is determined by functional demands, then the latter must not operate continuously lest growth go on without interruption and lead to overproduction of functional units. Only renewing tissues can tolerate perpetual growth because they get rid of excess structures as fast as they are formed. Endocrine and exocrine glands are in most cases known to function discontinuously and are thus not in danger of being overstimulated. The heart, lungs, and kidneys (and brain?), however, must work incessantly. Were their functional units capable of hyperplasia and at the same time subject to control by functional demand, then overgrowth would seem to be inevitable. By giving up the potential for hyperplasia in favor of the necessity for constant function, these organs have adopted a strategy that enables them to become hypertrophic to a limited extent while doing their jobs efficiently.

It is a curious fact that the unrestricted proliferation of biological structures cannot occur at all levels of organization. The counterpart of cancer, which is a cellular phenomenon, does not exist among molecules or cytoplasmic organelles, nor is it known to occur at the histological level of organization. Even in organs made up of histological units of function and having the potential for unlimited hyperplasia (for example, liver, exocrine glands, thyroid, ovary), the population of functional units never exceeds the number needed to fulfill the physiological requirements of the body. Above and below the level of the cell, therefore, structures are not permitted to escape the constraints of functional demands which control their production. The fact that cells can occasionally do so when they become neoplastic may reveal as much as it conceals about the problem of growth regulation.
Gibberellin-like Substances in the Developing Apricot Fruit
Authors: Jackson D. I. , Coombe B. G.
Published: October 2006

The concentrations of gibberellin-like substances in the seed, endocarp, and mesocarp of apricots correlates well with growth rates in these tissues between anthesis and maturity. The active substances are present in high concentration, are more polar than the known gibberellins, and are active in both the barley endosperm and dwarf maize bioassays.
Maya Blue: A Clay-Organic Pigment?
Authors: Van Olphen H.
Published: October 2006

Maya Blue, a pigment used by the Mayas in Yucatan, is remarkably stable: the color is not destroyed by hot concentrated mineral acids or by heating to about 250°C. The principal constituent is the colorless mineral attapulgite. It is proposed that the pigment is an adsorption complex of attapulgite and natural indigo; a synthetic equivalent may be prepared from attapulgite and either indoxylester or indigo, or by applying the vat-dyeing technique, with reduced indigo. The low dye content of the pigment (less than 0.5 percent) indicates that the dye is absorbed only on the external surfaces of the attapulgite particles and not throughout the channels in their structures. The complex as such is not stable to acids, but the stability displayed by Maya Blue is achieved simply by heating the complex to from 75° to 150°C for several days. An analogous stable pigment can be prepared from sepiolite and indigo. No stable pigments could be prepared from clays with platelike structures or from zeolites.
Pacific Pleistocene Cores: Faunal Analyses and Geochronology
Authors: Blackman Abner , Somayajulu B. L. K.
Published: October 2006

Two cores from the eastern Pacific were analyzed faunally and dated by the ionium: thorium method. Comparison of the results of these and of similar studies of Atlantic cores indicate that faunal changes, representing changes between the glacial and interglacial stages of the Pleistocene, occurred in both oceans simultaneously.
Chlorinated Hydrocarbon Pesticides: Degradation by Microbes
Authors: Chacko C. I. , Lockwood J. L. , Zabik Matthew
Published: October 2006

In culture, most of the actinomycetes and filamentous fungi tested degraded PCNB; several actinomycetes dechlorinated DDT to DDD, but no microorganism degraded dieldrin.
Streptomyces aureofaciens
degraded PCNB to pentachloroaniline.
Sweet-Sensitive Protein from Bovine Taste Buds: Isolation and Assay
Authors: Dastoli Frank R. , Price Steven
Published: October 2006

Using refractometry and ultraviolet-difference spectroscopy to indicate interaction between proteins and compounds of low molecular weight, we found a protein fraction in bovine tongue extracts that complexes sugars and saccharin. The strengths of the complexes parallel the degrees of sweetness of the compounds, and the effects of
p
H upon formation of complexes parallel the effects of
p
H upon sensitivity of taste buds to sweet compounds in vivo.
Visual Spatial Aftereffect from Prolonged Head-Tilt
Authors: Day R. H. , Wade N. J.
Published: October 2006

Subjects with head upright were required to adjust a lighted bar in a dark room until the bar appeared vertical; the task was performed before and after 2 and 3 minutes of lateral head-tilt with their eyes closed. A visual spatial aftereffect was observed which varied as a function of the angle of head-tilt and which was opposite in direction to head-tilt.
Cell-Free Protein Synthesis: Effects of Age and State of Ribosomal Aggregation
Authors: Moore L. Daneo , Kocun F. J. , Umbreit W. W.
Published: October 2006

In cell-free extracts derived from
Streptococcus faecalis
, protein synthesis directed by endogenous messenger RNA increases as the culture ages. The increased activity is accompanied by an increase in the percentage of membrane-bound ribosomes and by a decrease in ribosomal monomers and subunits. These changes progress against a background of structural and compositional modifications in the membrane. Membrane modifications possibly related to endogenously directed protein synthesis in cell-free extracts include: (i) decreased specific activity of a membrane-associated polynucleotide phosphorylase capable of polysome degradation, and (ii) increased concentrations of certain phospholipids.
Control of the Activity of
Escherichia coli
Carbamoyl Phosphate Synthetase by Antagonistic Allosteric Effectors
Authors: Piérard André
Published: October 2006

The synthesis of carbamoyl phosphate required in both arginine and pyrimidine biosyntheses is carried out by a single enzyme in
Escherichia coli
. Opposed effects of pyrimidine nucleotides and of ornithine on the activity of the enzyme ensure a proper supply of carbamoyl phosphate according to the needs of the two biosynthetic sequences.
Entrainment of Circadian Rhythms by Sound in
Passer domesticus
Authors: Menaker Michael , Eskin Arnold
Published: October 2006

The circadian locomotor rhythm of house sparrows was entrained by a sound stimulus. The birds were maintained at a constant temperature in, dim green light. The entraining agent was 4½ hours of tape-recorded bird song played each day. Variations in the response to this stimulus have been correlated with individual variations in free-running period. This is the first clear demonstration that a biological clock can be influenced by sound stimuli.
Ozone Depletion: Ultraviolet Radiation and Phytoplankton Biology in Antarctic Waters
Authors: Smith R. C. , Prézelin B. B. , Baker K. S. , Bidigare R. R. , Boucher N. P. , Coley T. , Karentz D. , MacIntyre S. , Matlick H. A. , Menzies D. , Ondrusek M. , Wan Z. , Waters K. J.
Published: October 2006

The springtime stratospheric ozone (O
3
) layer over the Antarctic is thinning by as much as 50 percent, resulting in increased midultraviolet (UVB) radiation reaching the surface of the Southern Ocean. There is concern that phytoplankton communities confined to near-surface waters of the marginal ice zone will be harmed by increased UVB irradiance penetrating the ocean surface, thereby altering the dynamics of Antarctic marine ecosystems. Results from a 6-week cruise (Icecolors) in the marginal ice zone of the Bellingshausen Sea in austral spring of 1990 indicated that as the O
3
layer thinned: (i) sea surface- and depth-dependent ratios of UVB irradiance (280 to 320 nanometers) to total irradiance (280 to 700 nanometers) increased and (ii) UVB inhibition of photosynthesis increased. These and other Icecolors findings suggest that O
3
-dependent shifts of in-water spectral irradiances alter the balance of spectrally dependent phytoplankton processes, including photoinhibition, photoreactivation, photoprotection, and photosynthesis. A minimum 6 to 12 percent reduction in primary production associated with O
3
depletion was estimated for the duration of the cruise.
The Conformation of Fluid Membranes: Monte Carlo Simulations
Authors: Kroll D. M. , Gompper G.
Published: October 2006

The conformation and scaling properties of self-avoiding fluid membranes with an extrinsic bending rigidity κ were studied with the use of Monte Carlo methods. For κ = 0, the results are consistent with branched polymer behavior at large length scales. There is a smooth crossover from a crumpled to an extended state with increasing κ, with a peak in the specific heat when the persistence length reaches the system size. The scale-dependent effective bending rigidity is a decreasing function of system size for all bare rigidities. These results indicate that fluid membranes are always crumpled at sufficiently long length scales.
Form-Cue Invariant Motion Processing in Primate Visual Cortex
Authors: Albright Thomas D.
Published: October 2006

The direction and rate at which an object moves are normally not correlated with the manifold physical cues (for example, brightness and texture) that enable it to be seen. As befits its goals, human perception of visual motion largely evades this diversity of cues for image form; direction and rate of motion are perceived (with few exceptions) in a fashion that does not depend on the physical characteristics of the object. The middle temporal visual area of the primate cerebral cortex contains many neurons that respond selectively to motion in a particular direction and is an integral part of the neural substrate for perception of motion. When stimulated with moving patterns characterized by one of three very diverse cues for form, many middle temporal neurons exhibited similar directional tuning. This lack of sensitivity for figural cue characteristics may allow the uniform perception of motion of objects having a broad spectrum of physical cues.
Converting Trypsin to Chymotrypsin: The Role of Surface Loops
Authors: Hedstrom Lizbeth , Szilagyi Laszlo , Rutter William J.
Published: October 2006

Trypsin (Tr) and chymotrypsin (Ch) have similar tertiary structures, yet Tr cleaves peptides at arginine and lysine residues and Ch prefers large hydrophobic residues. Although replacement of the S1 binding site of Tr with the analogous residues of Ch is sufficient to transfer Ch specificity for ester hydrolysis, specificity for amide hydrolysis is not transferred. Trypsin is converted to a Ch-like protease when the binding pocket alterations are further modified by exchange of the Ch surface loops 185 through 188 and 221 through 225 for the analogous Tr loops. These loops are not structural components of either the S1 binding site or the extended substrate binding sites. This mutant enzyme is equivalent to Ch in its catalytic rate, but its substrate binding is impaired. Like Ch, this mutant utilizes extended substrate binding to accelerate catalysis, and substrate discrimination occurs during the acylation step rather than in substrate binding.
Frost Phenomena on Mars
Authors: Anderson Duwayne M. , Gaffney Edward S. , Low Philip F.
Published: October 2006

The hypothesis that the Martian wave of darkening might be a frost-heaving phenomenon has been examined. Consideration of the water-vapor sorption characteristics of a silicate mineral surface at temperatures below freezing leads to the conclusion that, without strongly deliquescent salts to attract and retain liquid water in the Martian soil, frost-heaving phenomena are not to be expected on Mars. On the other hand frost-heaving phenomena involving the freezing and thawing of ammonia may be common in the soils of Jupiter.
Digital Model of Evaporite Sedimentation
Authors: Briggs L. I. , Pollack H. N.
Published: October 2006

A deterministic digital model to simulate evaporite sedimentation permits experimentation with depth of water, shape of salt basin, number, position, and strength of the inlets, and rate of evaporation. It provides a reasonable fit to salt thickness and distribution in the Upper Silurian Salina Formation of Michigan.
Privacy and Behavioral Research
Authors:   Panel on Privacy and Behavioral Research
Published: October 2006

From our examination of the relation of behavioral science research to the right to privacy, we have been led to the following conclusions.

1) While most current practices in the field pose no significant threat to the privacy of research subjects, a sufficient number of exceptions have been noted to warrant a sharp increase in attention to procedures that will assure protection of this right. The increasing scale of behavioral research is itself an additional reason for focusing attention in this area.

2) Participation by subjects must be voluntary and based on informed consent to the extent that this is consistent with the objectives of the research. It is fully consistent with the protection of privacy that, in the absence of full information, consent be based on trust in the qualified investigator and the integrity of his institution.

3) The scientist has an obligation to insure that no permanent physical or psychological harm will ensue from the research procedures, and that temporary discomfort or loss of privacy will be remedied in an appropriate way during the course of the research or at its completion. To merit trust, the scientist must design his research with a view to protecting, to the fullest extent possible, the privacy of the subjects. If intrusion on privacy proves essential to the research, he should not proceed with his proposed experiment until he and his colleagues have considered all of the relevant facts and he has determined, with support from them, that the benefits outweigh the costs.

4) The scientist has the same responsibility to protect the privacy of the individual in published reports and in research records that he has in the conduct of the research itself.

5) The primary responsibility for the use of ethical procedures must rest with the individual investigator, but government agencies that support behavioral research should satisfy themselves that the institution which employs the investigator has effectively accepted its responsibility to require that he meet proper ethical standards.

6) Legislation to assure appropriate recognition of the rights of human subjects is neither necessary nor desirable if the scientists and sponsoring institutions fully discharge their responsibilities in accommodating to the claim of privacy. Because of its relative inflexibility, legislation cannot meet the challenge of the subtle and sensitive conflict of values under consideration, nor can it aid in the wise decision making by individuals which is required to assure optimum protection of subjects, together with the fullest effectiveness of research.
Direction-Selective Units in Rabbit Retina: Distribution of Preferred Directions
Authors: Oyster Clyde W. , Barlow Horace B.
Published: October 2006

The preferred directions of 102 direction-selective ganglion cells in the rabbit retina have been determined. Cells of the "on-off" type form four nonoverlapping groups; cells of the "on" type fall into three groups. The on-off groups appear to correspond to the directions of apparent object displacement produced by contractions of the four rectus muscles. Each group of cells could, without further processing, provide the error signal for a visual servo-system minimizing retinal image motion.
Nobiletin Is Main Fungistat in Tangerines Resistant to Mal Secco
Authors: Ben-Aziz A.
Published: October 2006

A number of crystalline compounds isolated from peel of tangerines resistant to "mal secco" were characterized and tested for fungistatic activity toward
Deuterophoma tracheiphila
. Nobiletin exhibited strong fungistatic activity, tangeritin was weakly active, and hesperidin slightly stimulated fungal growth. Rough lemon seedlings, inoculated with the pathogenic fungus, rapidly developed the symptoms of mal secco, whereas continuous infusion of the inoculated seedlings with nobiletin solution largely prevented appearance of the disease.
Magnesium Pemoline: Failure To Affect in vivo Synthesis of Brain RNA
Authors: Morris N. Ronald , Aghajanian George K. , Bloom Floyd E.
Published: October 2006

The effect of magnesium pemoline on the synthesis of brain RNA in vivo was studied. No significant effect either on the concentration of RNA or on the uptake of H
3
-uridine into RNA was detected.
Circadian Pattern of Plasma 17-Hydroxycorticosteroid: Alteration by Anticholinergic Agents
Authors: Krieger Dorothy T. , Krieger Howard P.
Published: October 2006

Atropine, administered to cats just prior to the time of the expected circadian rise in levels of 17-hydroxycorticosteroid in plasma, blocks this rise. Atropine does not alter this circadian pattern when administered at other times in the circadian cycle. Results similar to those obtained with atropine have been observed with short-acting barbiturates. Dibenzyline administered just prior to the time of the expected circadian rise is ineffective in blocking this rise. These findings support the hypothesis that the circadian pattern of plasma 17-hydroxycorticosteroid levels reflects activation, by the central nervous system, of the hypothalamicpituitary-adrenal axis during a "critical time period" in the circadian cycle.
Bluetongue Virus Infection: Pathologic Responses of Nervous Systems in Sheep and Mice
Authors: Richards W. P. C. , Cordy D. R.
Published: October 2006

Lesions caused by bluetongue virus infection of the central nervous systems of sheep and mice vary with age of the host. The character of the lesions appears to be influenced by the stage of immunological maturity of the infected animals.
Transverse Tubule Apertures in Mammalian Myocardial Cells: Surface Array
Authors: Rayns D. G. , Simpson F. O. , Bertaud W. S.
Published: October 2006

The technique of "freeze-etching" tissues for electron microscopy has permitted observation of the external apertures of the transverse tubules. The apertures appear on the cell surface in approximately parallel rows, which can be interpreted as corresponding longitudinally to the spaces between the myofibrils and transversely to the Z regions of the myofibrils.
Surface Tension and Surface Structure of Water
Authors: Claussen Walter F.
Published: October 2006

The surface tension-temperature relationship for water is smooth and linear when account is taken of the expansion of the surface with temperature. This plot permits the calculation of thermodynamic properties for 1 square centimeter of surface. Molar surface quantities are derived by assuming a hexagonal water surface structure.