bluuebunny/crossref_metadata_2025 huggingface dataset:
Aflatoxin B
2
: Chemical Identity and Biological Activity
Authors: Chang Sea Bong , Abdel Kader M. M. , Wick Emily L. , Wogan Gerald N.
Published: October 2006

Aflatoxin B
2
, a blue-fluorescent metabolite of
Aspergillus flavus
, was isolated from cultures grown on crushed wheat. Chemical structure of the compound was elucidated as dihydroaflatoxin B
1
. Biological activity was determined in day-old male white Pekin ducklings. The criteria of activity were reduction in growth and liver size and the extent of bile-duct hyperplasia.
Carbonate Rocks: Cleaning with Suspensions of Hydrogen-Ion Exchange Resin
Authors: Percival Stephen F. , Glover Everett D. , Gibson Lee B.
Published: October 2006

The surface of carbonate rocks may be cleaned by etching or polishing or both, with hydrogen-ion exchange resin. This treatment reveals details in texture and fossil morphology so clearly that thin sections may be often dispensed with. Of four cleaning methods, (i) allowing resin to settle around the sample, (ii) stirring with a magnetic stirrer, (iii) agitating with an ultrasonic generator, and (iv) directing a jet stream at the sample, the first method was best for large specimens and the second method was best for well cuttings and chips.
Polonium-210: A Volatile Radioelement in Cigarettes
Authors: Radford Edward P. , Hunt Vilma R.
Published: October 2006

Polonium-210, which emits alpha particles, is a natural contaminant of tobacco. For an individual smoking two packages of cigarettes a day, the radiation dose to bronchial epithelium from Po
210
inhaled in cigarette smoke probably is at least seven times that from background sources, and in localized areas may be up to 1000 rem or more in 25 years. Radiation from this source may, therefore, be significant in the genesis of bronchial cancer in smokers.
Reduction of Transpiration of Leaves through Stomatal Closure Induced by Alkenylsuccinic Acids
Authors: Zelitch Israel
Published: October 2006

Low concentrations of long-chain alkenylsuccinic acids and certain of their derivatives inhibit stomatal opening in a tobacco-leaf disk assay, and when used as a spray. The monomethyl ester of decenylsuccinic acid is presently the most effective of this class of compounds. Stomatal closure induced with this substance is accompanied by a significant reduction in the rate of transpiration. These inhibitors probably close stomata by altering the permeability of the membranes of the guard cells.
Ikaros, an Early Lymphoid-Specific Transcription Factor and a Putative Mediator for T Cell Commitment
Authors: Georgopoulos Katia , Moore David D. , Derfler Bruce
Published: October 2006

In a screen for transcriptional regulators that control differentiation into the T cell lineage, a complementary DNA was isolated encoding a zinc finger protein (Ikaros) related to the
Drosophila
gap protein Hunchback. The Ikaros protein binds to and activates the enhancer of a gene encoding an early T cell differentiation antigen, CD3δ. During development, Ikaros messenger RNA was first detected in the mouse fetal liver and the embryonic thymus when hematopoietic and lymphoid progenitors initially colonize these organs; no expression was observed in the spleen or the bone marrow. The pattern of Ikaros gene expression and its ability to stimulate CD3δ transcription support the model that Ikaros functions in the specification and maturation of the T lymphocyte.
Direct Mechanical Measurements of the Elasticity of Single DNA Molecules by Using Magnetic Beads
Authors: Smith Steven B. , Finzi Laura , Bustamante Carlos
Published: October 2006

Single DNA molecules were chemically attached by one end to a glass surface and by their other end to a magnetic bead. Equilibrium positions of the beads were observed in an optical microscope while the beads were acted on by known magnetic and hydrodynamic forces. Extension versus force curves were obtained for individual DNA molecules at three different salt concentrations with forces between 10
-14
and 10
-11
newtons. Deviations from the force curves predicted by the freely jointed chain model suggest that DNA has significant local curvature in solution. Ethidium bromide and 4′,6-diamidino-2-phenylindole had little effect on the elastic response of the molecules, but their extent of intercalation was directly measured. Conversely, the effect of bend-inducing
cis
-diamminedichloroplatinum (II) was large and supports the hypothesis of natural curvature in DNA.
Assignment of a Locus for Familial Melanoma, MLM, to Chromosome 9p13-p22
Authors: Cannon-Albright Lisa A. , Goldgar David E. , Meyer Laurence J. , Lewis Cathryn M. , Anderson David E. , Fountain Jane W. , Hegi Monika E. , Wiseman Roger W. , Petty Elizabeth M. , Bale Allen E. , Olopade Olufunmilayo I. , Diaz Manuel O. , Kwiatkowski David J. , Piepkorn Michael W. , Zone John J. , Skolnick Mark H.
Published: October 2006

Linkage analysis of ten Utah kindreds and one Texas kindred with multiple cases of cutaneous malignant melanoma (CMM) provided evidence that a locus for familial melanoma susceptibility is in the chromosomal region 9p13-p22. The genetic markers analyzed reside in a candidate region on chromosome 9p21, previously implicated by the presence of homozygous deletions in melanoma tumors and by the presence of a germline deletion in an individual with eight independent melanomas. Multipoint linkage analysis was performed between the familial melanoma susceptibility locus (MLM) and two short tandem repeat markers, D9S126 and the interferon-α (IFNA) gene, which reside in the region of somatic loss in melanoma tumors. An analysis incorporating a partially penetrant dominant melanoma susceptibility locus places MLM near IFNA and D9S126 with a maximum location score of 12.71. Therefore, the region frequently deleted in melanoma tumors on 9p21 presumably contains a locus that plays a critical role in predisposition to familial melanoma.
Mutant Mice (Quaking and Jimpy) with Deficient Myelination in the Central Nervous System
Authors: Sidman Richard L. , Dickie Margaret M. , Appel Stanley H.
Published: October 2006

Two mutant mice with deficient myelination are described. Quaking is a new autosomal recessive mutant mouse with marked tremor of the hindquarters. The mice eat, swim, breed, and nurse well even though the entire central nervous system is very deficient in myelin by histological and chemical criteria. Myelin formation is impaired; no destruction is seen. Peripheral nerves are myelinated. Jimpy, a known sex-linked mutation, has similar but more severe symptoms and similar pathology, with the additional feature of sudanophilic (nonpolar) lipid distributed in some white-matter tracts. Both mutants offer new opportunities for study of the formation and functions of myelin.
Inhibition of Bacterial Growth by Drugs of the Morphine Series
Authors: Simon Eric J.
Published: October 2006

The growth of
Escherichia coli
is reversibly inhibited by drugs of the morphine series. The order of inhibitory effectiveness for the drugs tested was levallorphan > levorphanol > dextrorphan > nalorphine > morphine. The synthetic analgesic, levorphanol, was studied in greater detail. Its effectiveness was found to be strongly dependent on the
p
H of the medium. Raising the
p
H of the medium provides a higher concentration of the neutral free base which is thought to diffuse across cell membranes more readily. However, considerations other than the rate of entry of drug into the cells must be of importance since an already established growth inhibition is promptly reversed upon lowering the
p
H of the medium. Two mutants of
Escherichia coli
with altered sensitivity to levorphanol were isolated.
Blindness: Its Relation to Age of Menarche
Authors: Zacharias Leona , Wurtman Richard J.
Published: October 2006

Blindness in human females is associated with an age of menarche which is earlier than normal. When blindness is accompanied by a total loss of light perception, menarche is even earlier.
Intermolecular Cross-Linking of Collagen and the Identification of a New Beta-Component
Authors: Bornstein Paul , Martin G. R. , Piez Karl A.
Published: October 2006

Extraction of skin with 5
M
guanidine after salt and acid extraction yields a gelatin fraction which contains a greater proportion of double-chain (β) components than can be accounted for by intramolecular cross-linking of collagen molecules. This fraction also contains a new β-component, identified as the dimer of α2 and designated β
22
. This dimer must be formed by intermolecular crosslinking since each collagen molecule contains only one α2 chain. Thus, direct evidence is presented for the occurrence of both inter- and intramolecular crosslinking by what appears to be a single continuous process.
Hybrid Resistance to Parental Marrow Grafts: Association with the K Region of H-2
Authors: Cudkowicz Gustavo , Stimpfling J. H.
Published: October 2006

Bone marrow of homozygous C57BL/10 donors was tested for growth in x-irradiated isogenic recipient mice, in (C57BL/10 × 129)F
1
mice, and in F
1
hybrids from congenic parents differing respectively, for an allelic substitution at one of the histocompatibility loci
H-1
,
H-2
,
H-3
, and
H-4
. All the tested
H-2
heterozygotes resisted the transplantation of 10
6
parental marrow cells, whereas
H-2
homozygotes were nonresistant, in spite of heterozygosity, at one or several other
H
loci. Findings in F
1
hybrids between C57BL/10 mice and mice carrying alleles resulting from crossing-over within the
H-2
locus demonstrated that the hybrid resistance was associated with heterozygosity in the K region, but not in the D region of the
H-2
locus.
X-ray Diffraction Studies on Dysprosium at High Pressures
Authors: Jamieson John C.
Published: October 2006

Dysprosium has been studied at pressures up to about 160 kilobars, well above the transition reported near 50 kilobars by other workers. It shows no definite structural alteration from hexagonal close-packed structure throughout this range. It is suggested that the 50-kilobar transition is most likely electronic or magnetic in nature, or that the metal undergoes a hexagonal stacking rearrangement.
Kope Formation (Upper Ordovician): Ohio and Kentucky
Authors: Weiss Malcolm P. , Sweet Walter C.
Published: October 2006

Eden-like strata near Maysville, Kentucky, may be correlated with the Eden and lower Fairview formations of Cincinnati. To avoid the name Eden, which has stadial connotation, these rocks are included in the Kope formation, defined as medium-bedded limy shales (mean clastic ratio, 2.5 to 3.8) resting conformably between shaly Point Pleasant limestones (mean clastic ratio, 1.0) and unnamed shaly limestones (mean clastic ratio, 0.5).
Hydrazine-Water System: The Water-Rich Eutectic
Authors: McMillan J. A. , Los S. C.
Published: October 2006

The melting point and composition of the water-rich eutectic of hydrazine and water have been determined by differential thermal analysis as 193° ± 0.5°K and 27 ± 1 mole percent hydrazine, respectively.
Complex Visual Concept in the Pigeon
Authors: Herrnstein R. J. , Loveland D. H.
Published: October 2006

Pigeons were trained to respond to the presence or absence of human beings in photographs. The precision of their performances and the ease with which the training was accomplished suggest greater powers of conceptualization than are ordinarily attributed to animals.
Sporangium Discharge in
Pilobolus
: A Photographic Study
Authors: Page Robert M.
Published: October 2006

Stages in the discharge of sporangia by the fungus,
Pilobolus kleinii
, were photographed by means of a high-speed electronic flash triggered by a photocell. The photographs confirm that the sporangium is propelled by a jet of cell sap. The jet is deflected from the sporangium and attains a considerable length before it breaks into droplets.
Electroconductive Polymers
Authors: Lupinski J. H. , Kopple K. D.
Published: October 2006

Polymers of a new type with an unusual combination of properties have been synthesized. They are of high molecular weight, they are soluble in organic solvents, and they can be cast as films. Their electrical conduction is electronic in the solid state and can be controlled up to a conductivity of 10
-3
ohm
-1
cm
-1
.
Sulfur: Role in Genesis of Petroleum
Authors: Douglas Archibald G. , Mair Beveridge J.
Published: October 2006

Sulfur reacts readily with cholesterol at 150°C, and the product of the reaction contains aromatic hydrocarbons, some with a benzene, some a naphthalene, and some a phenanthrene ring system as part of the molecule. The reaction of farnesol with sulfur takes place at 135°C. Cadalene (1,6-dimethyl-4-isopropylnaphthalene) is one of the products of the reaction. These reactions at relatively low temperatures support the proposition that a thermal reaction of sulfur with terpenoids and steroids plays a part in the genesis of petroleum.
Hepatomas in Mice: Incidence Increased after Gamma Irradiation at Low Dose Rates
Authors: Nowell Peter C. , Cole Leonard J.
Published: October 2006

Irradiation of LAf
1
mice with gamma-rays (total doses of 618 to 1335 rad) at a rate of 1.45 rad per hour markedly increased the incidence of hepatomas and ovarian adenomas, compared with incidence of these tumors in mice irradiated with x-rays at 30 rad per minute. This was somewhat unexpected, since chromosome aberrations in the liver cells were less frequent after irradiation at the low dose rate. Other types of tumors were not increased by irradiation with gamma-rays at the low dose rate. It is suggested that indirect hormonal mechanisms may contribute to the production of the hepatomas as well as of the ovarian adenomas.
Serotonin and Adenosine Triphosphate: Synergistic Effect on the Beat Frequency of Cilia of Mussel Gills
Authors: Schor Seth L.
Published: October 2006

For each tenfold increase in the concentration of serotonin in the range 10
-7
to 10
-4
M
, the beat frequency of the lateral cilia of the gills of the freshwater mussel Elliptio complanatus increases by approximately two beats per second over the mean frequency of 14.5 beats per second for control gills perfused with 0.04
M
potassium chloride. The addition of 10
-6
to 10
-3
M
concentrations of adenosine triphosphate has no detectable effect on the beat frequency. The addition of both serotonin and 10
-4
M
adenosine triphosphate increases the frequency by two beats per second more than does the addition of serotonin alone.
Radioactivity: Detection of Gamma-Ray Emission in Sediments in situ
Authors: Jennings David , Cutshall Norman , Osterberg Charles
Published: October 2006

A probe for measuring emission of γ-rays in sedimentsin situin water depths to about 35 meters was used to measure radioactivity in the Columbia River estuary and Oregon coastal areas. This technique offers some advantage over methods in which sediment samples are collected at sea and returned to the laboratory for radioanalysis.
Endemism in Middle Miocene Caribbean Molluscan Faunas
Authors: Woodring W. P.
Published: October 2006

The term "middle Miocene Caribbean province" is used for a faunal province that embraced both western Atlantic and eastern Pacific waters. The percentage of endemic species in 13 local faunas in that province is tabulated. In general the largest faunas have the highest percentage of endemic species, but notable exceptions to that generalization are apparent. Many examples of discontinuous distribution of species and genera, which are not relicts, support the conclusion that much of the endemisim is apparent rather than real.
Lungfish Burrows from the Michigan Coal Basin
Authors: Carroll Robert L.
Published: October 2006

Five casts of lungfish burrows have been found in a quarry near Grand Ledge, Michigan, in shale of the Saginaw group, Middle Pennsylvanian. The burrows contain no fish remains, but they closely resemble lungfish burrows from the Lower Permian of Texas which contain remains of the genus
Gnathorhiza
.
Defensive Spray of a Phasmid Insect
Authors: Eisner Thomas
Published: October 2006

The walkingstick,
Anisomorpha buprestoides
, has two defensive glands in its thorax from which it ejects an aimed spray when disturbed. Contact stimulation is the usual trigger for the discharge, but birds may elicit the spray by merely approaching the insect. The secretion proved effectively deterrent to ants, predaceous beetles, mice, and blue jays, but not to an opossum.
Retrograde Amnesia from Electroconvulsive Shock in a One-Trial Appetitive Learning Task
Authors: Tenen S. S.
Published: October 2006

Rats deprived of water were placed, for 4-minute sessions, into a chamber containing a hole in one wall. After several sessions the number of times these rats explored the hole markedly decreased. Rats given access to water at the hole for a brief period explored the hole more frequently than controls, when they were tested later. This increase in hole explorations was abolished when the water reinforcement was followed by electroconvulsive shock but not when followed by foot shock.
Lactic Acid Metabolism in Hypertensive Patients
Authors: Demartini F. E. , Cannon P. J. , Stason W. B. , Laragh J. H.
Published: October 2006

In patients (93) with either essential or renal hypertension the concentration of lactic acid in both venous and arterial blood was significantly (
p
< .001) elevated, whereas there was no significant increase (
p
< .127) in the concentration of blood pyruvate. Neither renal insufficiency nor various modes of therapy could be correlated with this increase in lactic acid.
Circadian Rhythms in Male Ants of Five Diverse Species
Authors: McCluskey Elwood S.
Published: October 2006

When kept at constant temperature and subjected to a daily cycle of light and darkness, males of
Paraponera clavata
,
Iridomyrmex humilis
,
Solenopsis saevissima
,
Veromessor andrei
, and
Camponotus clarithorax
were active at different hours. With
Solenopsis
and
Veromessor
the active hours relative to the laboratory dawn corresponded with the hours of mating flight in the field. In four of the five species the rise preceding maximum activity began before change to light or to darkness. This endogenous behavior, widespread in males, is of interest because timing in the worker caste has been questioned.
Visnagin: Biosynthesis and Isolation fromAmmi visnagiSuspension Cultures
Authors: Kaul Balkrishena , Staba E. John
Published: October 2006

During an examination ofAmmi visnagaLam. suspension cultures for the biosynthesis of furanochromones and related medicinal compounds, visnagin was isolated in crystalline form and identified. Thus, certain medicinally important secondary plant metabolites may be produced in appreciable amounts by plant tissue cultures.
Inhibition of Bone Formation During Space Flight
Authors: Morey Emily R. , Baylink David J.
Published: October 2006

Parameters of bone formation and resorption were measured in rats orbited for 19.5 days aboard the Soviet Cosmos 782 biological satellite. The most striking effects were on bone formation. During flight, rats formed significantly less periosteal bone than did control rats on the ground. An arrest line at both the periosteum and the endosteum of flight animals suggests that a complete cessation of bone growth occurred. During a 26-day postflight period, the defect in bone formation was corrected. No significant changes in bone resorption were observed.
Trehalase from
Dictyostelium discoideum
: Purification and Properties
Authors: Ceccarini Costante
Published: October 2006

The hydrolytic enzyme, trehalase, was isolated and purified approximately 90-fold from the cellular slime mold
Dictyostelium discoideum
. The purified trehalase has an optimal temperature of 45°C and shows maximum activity at
p
H 5.5 in citrate buffer. Its Michaelis constant is 1.2 × 10
-3
M.
Naphthaleneacetic Acid: Localization in the Abscission Zone of the Bean
Authors: Rasmussen H. P. , Bukovac M. J.
Published: October 2006

When14C-naphthaleneacetic acid, labeled in the ring, was applied to the petiolar stub of debladed bean (Phaseolus vulgarisL.) plants, it accumulated in or between cell walls of tissue immediately adjacent and distal to the abscission layer. There was no localization in the abscission layer per se. Similar distribution patterns were observed in the abscission zone after naphthaleneacetic acid applications, which either delayed (10-3M) or accelerated (10-5M) abscission.
A 90-Kilodalton Endothelial Cell Molecule Mediating Lymphocyte Binding in Humans
Authors: Salmi Marko , Jalkanen Sirpa
Published: October 2006

Interactions between leukocyte surface receptors and their ligands on vascular endothelial cells control lymphocyte traffic between the blood and various lymphoid organs, as well as extravasation of leukocytes into sites of inflammation. A heretofore undescribed 90-kilodalton human endothelial cell adhesion molecule (VAP-1) defined by a monoclonal antibody 1B2 is described. The expression pattern, molecular mass, functional properties, and an amino-terminal amino acid sequence define VAP-1 as an endothelial ligand for lymphocytes. VAP-1 helps to elucidate the complex heterotypic cell interactions that direct tissue-selective lymphocyte migration in man.
Foraminiferal Evidence of a Shallow Calcium Carbonate Solution Boundary, Ross Sea, Antarctica
Authors: Kennett James P.
Published: October 2006

In the Ross Sea, Antarctica, distributions of calcareous Foraminifera and other calcareous microorganisms are dominantly controlled by a shallow calcium carbonate solution boundary that occurs at depths of about 500 meters. Possible causes of substantial undersaturation of Ross Sea bottom waters in calcium carbonate are very low temperatures and high salinities, which favor the solution of calcium carbonate and, possibly, high concentrations of carbon dioxide.
Fungus-Growing Ants
Authors: Weber Neal A.
Published: October 2006

Fungus-growing ants (Attini) are in reality unique fungus-culturing insects. There are several hundred species in some dozen genera, of which
Acromyrmex
and
Atta
are the conspicuous leaf-cutters. The center of their activities is the fungus garden, which is also the site of the queen and brood. The garden, in most species, is made from fresh green leaves or other vegetal material. The ants forage for this, forming distinct trails to the vegetation that is being harvested. The cut leaves or other substrate are brought into the nest and prepared for the fungus. Fresh leaves and flowers are cut into pieces a millimeter or two in diameter; the ants form them into a pulpy mass by pinching them with the mandibles and adding saliva. Anal droplets are deposited on the pieces, which are then forced into place in the garden. Planting of the fungus is accomplished by an ant's picking up tufts of the adjacent mycelium and dotting the surface of the new substrate with it. The combination of salivary and anal secretions, together with the constant care given by the ants, facilitates the growth of the ant fungus only, despite constant possibilities for contamination. When the ants are removed, alien fungi and other organisms flourish.

A mature nest of
Atta sexdens
may consist of 2000 chambers, some temporarily empty, some with refuse, and the remainder with fungus gardens. Thousands of kilograms of fresh leaves will have been used. A young laboratory colony of
Atta cephalotes
will use 1 kilogram of fresh leaves for one garden. The attines are the chief agents for introducing organic matter into the soil in tropical rain forests; this matter becomes the nucleus for a host of other organisms, including nematodes and arthropods, after it is discarded by the ants.

One ant species cultures a yeast; all others grow a mycelium. In the higher species the mycelium forms clusters of inflated hyphae. Mycologists accept as valid two names for confirmed fruiting stages:
Leucocoprinus
(or
Leucoagaricus
)
gongylophora
(Moeller 1893) and
Lepiota
n. sp.
Triploid-Diploid Mosaic Chicken Embryo
Authors: Bloom Stephen E. , Buss Edward G.
Published: October 2006

Cytological analysis of an underdeveloped chicken embryo at 6 days of incubation revealed a triploid-diploid mosaic condition. Of the 30 metaphases observed, 19 were triploid and 11 diploid. The triploid cells were 3A-ZZZ and diploid cells 2A-ZZ, as determined for the six largest pairs of chromosomes.
Some Doubts about the Earth's Dust Cloud
Authors: Nilsson Carl
Published: October 2006

Considerable doubt is cast on the validity of past satellite measurements of micrometeoroid fluxes in which piezoelectric microphones have been used as detectors. Data have been obtained from satellite and laboratory experiments which show that the microphone crystals emit noise when subject to slowly varying temperatures. The rate of noise is consistent with past flight data which have previously been interpreted on the basis of micrometeoroid impacts. These measurements have given rise to the theory that the earth is surrounded by a cloud of dust, although no satisfactory mechanism has yet been found to explain this apparent phenomenon. On the basis of the results reported here, it now appears that whether or not a concentration of dust exists in the vicinity of the earth, the data from satellite microphone measurements should not be used to support such a hypothesis.
Antibody Molecules: Discontinuous Heterogeneity of Heavy Chains
Authors: Roholt O. A. , Pressman D.
Published: October 2006

The heavy polypeptide chains of antibody (and of γG-immunoglobulin) molecules show discrete bands on disc electrophoresis. The same bands are present for chains from antibodies of the same or diverse specificities. Individual bands are of different intensities for chains from the different rabbits tested even if the antibodies are directed against the same hapten. The bands appear to represent classes of heterogeneous H-chains of the same size having discrete differences in mobilities with respect to a single charge difference.
Lead-210 and Polonium-210 in Tissues of Cigarette Smokers
Authors: Holtzman Richard B. , Ilcewicz Frank H.
Published: October 2006

Concentrations of lead-210 and polonium-210 in rib bones taken from 13 cigarette smokers were about twice those in six nonsmokers, the polonium-210 being close to radioactive equilibrium with the lead-210. In alveolar lung tissue the concentration of lead-210 in smokers was about twice that in nonsmokers. These differences are attributed to additional intake by inhalation of lead-210.
Electrical Resistivity Changes in Saturated Rock under Stress
Authors: Brace W. F. , Orange A. S.
Published: October 2006

Electrical resistivity of water-saturated crystalline rock such as granite, diabase, dunite, or quartzite changes by an order of magnitude prior to fracture of the rock in compression. The effect observed even under high confining pressure is due to formation of open cracks which first appear at one-third to two-thirds the fracture stress.
Phytohemagglutinin: Inhibition of the Agglutinating Activity by
N
-Acetyl-D-Galactosamine
Authors: Borberg H. , Woodruff J. , Hirschhorn R. , Gesner B. , Miescher P. , Silber R.
Published: October 2006

The effect of simple sugars on the agglutinating activity of phytohemagglutinin was studied.
N
-Acetyl-D-galactosamine selectively inhibits the agglutination of leukocytes and erythrocytes by phytohemagglutinin.
Cerebral Cortical Mechanisms of Reaching Movements
Authors: Kalaska John F. , Crammond Donald J.
Published: October 2006

Because reaching movements have a clear objective—to bring the hand to the spatial location of an object—they are well suited to study how the central nervous system plans a purposeful act from sensory input to motor output. Most models of movement planning propose a serial hierarchy of analytic steps. However, the central nervous system is organized into densely interconnected populations of neurons. This paradox between the apparent serial order of central nervous system function and its complex internal organization is strikingly demonstrated by recent behavioral, modeling, and neurophysiological studies of reaching movements.
Radiocarbon Dating and Archeology in North America
Authors: Johnson Frederick
Published: October 2006

The history of the development of a radiocarbon chronology shows how the establishment of the times of events and the order of them has greatly improved the understanding of prehistory in North America. This is true also of other parts of the world. Too little has been said of existing discordance between archeologically determined sequences, and interregional associations, and the radiocarbon chronology. It does appear that these will be resolved as additional dates are added and as the results become more finely calibrated so that secular variations may be accounted for.

The collaborative aspect of the venture was apparent at the outset. Nevertheless no one expects an archeologist to delve into nuclear physics and geochemistry, and vice versa. There is great need, nevertheless, for the man in the laboratory to comprehend the difficulties of sample collecting and of judgement of the significance of the source of organic matter to be dated. At the same time, the archeologist must become more familiar with the importance of the various steps in the processing of the sample and with, what is most vital, interpretation of the significance of the numbers that appear on the counters.
Fighting and Death from Stress in a Cockroach
Authors: Ewing L. S.
Published: October 2006

Fighting behavior, leading to the establishment of stable dominant-subordinate relationships between pairs of males, is described for the cockroach
Nauphoeta cinerea
. Deaths, which do not appear to be due to external damage, occur in subordinate animals as a result of fighting. The situation is likened to death from stress as found in mammals.
Chemical Exfoliation of Vermiculite and the Production of Colloidal Dispersions
Authors: Walker G. F. , Garrett W. G.
Published: October 2006

Chemical treatments involving ion exchange cause gross one-dimensional swelling in water of single crystals of vermiculite minerals. A delicate balance of forces holds the individual silicate layers (10 angstroms thick) parallel to one another although separated by several hundred angstroms. Colloidal dispersions produced from the swollen crystals are morphologically unique and show strong film-forming characteristics.
Time Measurement in Insect Photoperiodism: Reversal of a Photoperiodic Effect by Chilling
Authors: Saunders D. S.
Published: October 2006

Spectacular reversals of the photoperiodic control of diapause are obtained if females of
Nasonia vitripennis
are chilled for 4 hours in certain light-dark cycles. Experiments in which chilling is combined with short light breaks (night interruptions) show that the first peak of diapause inhibition moves in response to the chilling. This result provides an explanation for the photoperiodic reversal; it is also circumstantial evidence for the participation of circadian rhythms in photoperiodism.
Catalysis of Ester Hydrolysis by Mixed Micelles ContainingN-α-Myristoyl-L-Histidine
Authors: Ochoa-Solano Armando , Romero Guillermo , Gitler Carlos
Published: October 2006

Model compounds are described for the study of the properties of amino acid side chains in the surface of micelles. Mixed micelles ofN-α-myristoyl-L-histidine and cetyltrimethylammonium bromide catalyze the hydrolyses ofp-nitrophenyl acetate andp-nitrophenyl caprylate at much higher rates than imidazole or histidine do. The reaction shows a kinetic behavior similar to that of surface-catalyzed reactions.
Calcium-Selective Electrode with Liquid Ion Exchanger
Authors: Ross James W.
Published: October 2006

A simple calcium-selective electrode has been developed which is capable of measuring calcium ion activity in the presence of many common interfering ions. The electrode utilizes a liquid ion exchanger membrane containing the calcium salt of a disubstituted phosphoric acid.
Pesticide Transformation to Aniline and Azo Compounds in Soil
Authors: Bartha Richard , Pramer David
Published: October 2006

The herbicide 3′,4′-dichloropropionanilide decomposes in soil to carbon dioxide and 3,4-dichloroaniline. and two molecules of the latter compound are condensed to form 3,3′,4,4′-tetrachloroazobenzene. Soil microorganisms are involved in both transformations.
Chenopod and Amaranth Pollen: Electron-Microscopic Identification
Authors: Tsukada Matsuo
Published: October 2006

Electron-microscopic criteria for distinguishing chenopod and amaranth pollen have been found in the number of minute holes and spinules, and especially in the ratio between them, which is < 1.5 in amaranths and > 1.6 in chenopods. Sixty-eight percent of total fossil pollen from a Classic Maya level (carbon-14 age 1380 ± 120 B.P.) in a lake-sediment core from El Salvador belongs to wild amaranths, which presumably invaded corn fields. Fossil chenopodiaceous pollen from a depth of 3.85 meters (about 4000 years old) at Tinte, the Netherlands, is mostly
Atriplex littoralis
, which was evidently very common on coastal marshes in the middle sub-Boreal period.
X-rays from Sources 3C 273 and M 87
Authors: Friedman H. , Byram E. T.
Published: October 2006

An x-ray survey of the Virgo region revealed signals from the directions of 3C 273 and M 87. Three other x-ray sources appear in the region scanned, but do not fit any known radio sources. The x-ray flux (1 to 10 angstroms) from the direction of 3C 273 is about 1000 times weaker than from the strongest x-ray source, Sco XR-1. If the source is located at the cosmological distance of 500 megaparsecs, the x-ray luminosity is 7.3 × 10
45
ergs per second. The x-ray luminosity of M87 is 1.5 × 10
43
ergs per second.
Farming Systems and Political Growth in Ancient Oaxaca
Authors: Flannery Kent V. , Kirkby Anne V. T. , Kirkby Michael J. , Williams Aubrey W.
Published: October 2006

The Valley of Oaxaca's large flat floor, high water table, low erosion rate, and frost-free floodplain give it a higher agricultural potential than that of most surrounding areas. The development of the pot-irrigation system early in the Formative period gave it a head start over other valleys, where the low water table did not permit such farming; Oaxaca maintained its advantage by assimilating canal irrigation,
barbecho,
infield-outfield systems, flood-water farming, and hillside terracing as these methods arose. With the expansion of population in the high-water-table zone of the high alluvium, competition for highly productive land and manipulation of surpluses may have led to initial disparities in wealth and status; competition probably increased when canal-irrigation systems were added during the Middle Formative, improving some localities to the point where one residential group owned land more valuable than that of its neighbors.
Amnesia: A Function of the Temporal Relation of Footshock to Electroconvulsive Shock
Authors: Schneider Allen M. , Sherman William
Published: October 2006

When rats received a brief footshock upon stepping off an elevated platform, and an electroconvulsive shock 30 seconds or 6 hours afterward, amnesia was not observed 24 hours later. If a second footshock (noncontingent) was delivered 0.5 second before the electroconvulsive shock, amnesia was observed. The amnesia was temporary if conditioning was strong and permanent if conditioning was weak.
Lipoperoxidation of Lung Lipids in Rats Exposed to Nitrogen Dioxide
Authors: Thomas Heriberto V. , Mueller Peter K. , Lyman Richard L.
Published: October 2006

Absorption spectra characteristic of diene conjugation and typical for peroxidized polyenoic fatty acids can be induced in rat lung lipids after the rats have been exposed to a scant amount of nitrogen dioxide (1 part per million) for 4 hours. The peroxidative changes do not occur immediately but appear to reach a maximum between 24 and 48 hours after exposure. The prooxidant effect of this atmospheric pollutant in rat lung lipids may be partially prevented by prior treatment of the animal with large doses of alpha-tocopherol.
Electron Microscopy of Unstained Biological Material: The Polytropic Montage
Authors: Hart Roger G.
Published: October 2006

With use of an electronic picture-scanning device and a digital computer, electron micrographs taken of a specimen along several different directions can be superimposed to form a montage that is more informative than the component images. Preliminary results indicate that one may thus study unstained, unshadowed biological material at high resolution.
Sterol Requirement for Reproduction of a Free-Living Nematode
Authors: Hieb W. F. , Rothstein Morton
Published: October 2006

The free-living, hermaphroditic nematode
Caenorhabditis briggsae
has a nutritional requirement for sterols. It will reproduce indefinitely in a liquid medium containing only bacterial cells (
Escherichia coli
) and salts if various sterols are present. Several other lipid-soluble materials are ineffective in supporting reproduction.
Cues: Their Relative Effectiveness as a Function of the Reinforcer
Authors: Garcia J. , McGowan B. K. , Ervin F. R. , Koelling R. A.
Published: October 2006

Two cues, either size or flavor of food pellet, were conditionally paired with either malaise induced by x-ray or pain induced by shock in four groups of rats. The combination of flavor and illness produced as conditioned decrement in consumption, but that of size and illness did not. Conversely, the combination of size and pain produced an inhibition of eating, but flavor and pain did not. Apparently, effective associative learning depends on central neural convergence of the paired afferent input.
Chrome Pyrope: An Inclusion in Natural Diamond
Authors: Meyer Henry O. A.
Published: October 2006

Electron probe analyses of garnets that are rich in magnesium and that occur as inclusions in natural diamonds show that the chrome-garnet end member, Mg
3
Cr
2
Si
3
O
12
, is a major constituent (30 percent).
Estrus-Inducing Pheromone of Male Mice: Transport by Movement of Air
Authors: Whitten W. K. , Bronson F. H. , Greenstein J. A.
Published: October 2006

The proportion of female SJL/J mice exhibiting estrus when placed 2 meters downwind (6 meters per minute) from a group of 15 hybrid males was not significantly less than that of females placed directly under the males and exposed to their urine. The proportion of mice showing estrus when placed 2 meters upwind was significantly less than that of mice downwind or of mice below males, but not different from that of females remote from males. These findings show that the pheromone from male mice is volatile and further support the concept that it acts through olfactory receptors.
Drosophila melanogaster
Treated with LSD: Absence of Mutation and Chromosome Breakage
Authors: Grace Dale , Carlson Elof Axel , Goodman Philip
Published: October 2006

Injection of lysergic acid diethylamide in
Drosophila melanogaster
males induced no mutations or chromosome breaks in premeiotic, meiotic, or postmeiotic sperm. Tests included those for sex-linked lethals, sex-linked visibles, a specific visible (dumpy), and translocations. Some implications of these experiments are discussed.
Olefins of High Molecular Weight in Two Microscopic Algae
Authors: Gelpi E. , Oró J. , Schneider H. J. , Bennett E. O.
Published: October 2006

The hydrocarbon composition of two algae, a golden-brown (
Botryococcus braunii
) and a blue-green (
Anacystis montana
), has been investigated by gas chromatography-mass spectrometry. Both show distributions of aliphatic hydrocarbons of odd carbon numbers in the medium and high ranges of molecular weight, with maxima at n-C
17
and n-C
29
for
B. braunii
and n-C
17
and n-C
29
for
A. montana
. With the exception of the
n
-heptadecane of
A. montana
all the hydrocarbons are monoenes, dienes, or trienes. Since certain continental sediments and oils show similar distributions of alkanes with respect to carbon number, these organisms may be the precursors of the hydrocarbons in these formations.
Lupus Nephritis: Varying Complement-Fixing Properties of Immunoglobulin G Antibodies to Antigens of Cell Nuclei
Authors: Tojo Takeshi , Friou George J.
Published: October 2006

Relative complement-fixing activity of antibodies to nuclear antigens, including DNA, were determined in serums of 15 patients with, and 65 patients without, active lupus nephritis, by comparing titers obtained in two methods. High complement-fixing activity of antibody was found in the nephritis group and low activity in the others. Results with immunoglobulin G fractions were similar.
Diosgenin and β-Sitosterol: Isolation fromSolanum xanthocarpumTissue Cultures
Authors: Heble M. R. , Narayanaswami S. , Chadha M. S.
Published: October 2006

Diosgenin and β-sitosterol were isolated fromSolanum xanthocarpumcallus, crystallized, and chemically characterized. That these metabolites, particularly diosgenin, form in significant amounts in tissue culture may prove useful.
Dipleurozoa from Lower Silurian of North America
Authors: Johnson Helgi , Fox Steven K.
Published: October 2006

In a problematical fauna discovered in Australia, 152 meters below diagnostic Lower Cambrian species, are fossilized remains belonging in the phylum Coelenterata. These jellyfish-like fossils were defined as a new class (Dipleurozoa) by Harrington and Moore because of their strong bilateral symmetry and differentiated extremities. The class was not reported elsewhere before many specimens were discovered recently in the Shawangunk (Tuscarora) formation at Delaware Water Gap, Pennsylvania. Three new species belonging to a new genus can be recognized, the indication being that the class ranges stratigraphically from the infra-Cambrian to at least the Lower Silurian, and geographically from Australia to eastern North America.
Paleontological Evidence of Variations in Length of Synodic Month since Late Cambrian
Authors: Pannella Giorgio , MacClintock Copeland , Thompson Maxwell N.
Published: October 2006

The values of length of synodic month, obtained from tidally controlled periodical growth patterns in mollusks and stromatolites for several geologic periods, indicate that the deceleration rate of the earth's rotation has not been constant. Two breaks in slope, in the Pennsylvanian and Cretaceous, may be related to changes in distribution of continents, oceans, and adjacent shallow seas.
Biologic Precipitation of Fluorite
Authors: Lowenstam H. A. , McConnell Duncan
Published: October 2006

X-ray diffraction patterns show that the statoliths of marine mysid crustaceans are composed of fluorite, and that this mineral is also a principal phase of the gizzard plates of some tectibranch gastropods. A phosphatic phase is also indicated by chemical analyses in the gizzard plates, but its crystallochemical characterization has not been feasible by x-ray diffraction. The occurrence of fluorite in mysid statoliths confirms the earlier interpretations based on insufficient documentation. Fixation of fluorine in hard tissues of marine invertebrates is extensive in the shelf seawaters and minor in the bathyal zone of the oceans.
Sleep after Exercise
Authors: Hobson J. Allan
Published: October 2006

After moderate treadmill exercise, marked decreases in operant responding and in latency to onset of behavioral sleep occurs in cats. The sleep produced is characterized by enhancement of synchronized electroencephalographic activity with suppression of the desynchronized phase. The result is consistent with the theory that a function of synchronized sleep is to facilitate recovery from fatigue.
Induction of Brain D(—)-β-Hydroxybutyrate Dehydrogenase Activity by Fasting
Authors: Smith Arnold L. , Satterthwaite H. Sherwood , Sokoloff Louis
Published: October 2006

D(‾)- β-hydroxybutyrate dehydrogenase activity is very low in normal adult rat brain; but during fasting it increases severalfold in parallel with the ketosis. The increase may represent part of a mechanism by which the brain adapts to changing patterns of substrate supply during starvation.
Garnet-Like Structures of High-Pressure Cadmium Germanate and Calcium Germanate
Authors: Prewitt C. T. , Sleight A. W.
Published: October 2006

Crystals of CdGeO
3
grown at a pressure of 65 kilobars are tetragonal and have an ordered, garnet-like crystal structure with cadmium occupying the dodecahedral and octahedral sites, and germanium the octahedral and tetrahedral sites. The crystal structure (
a
= 12.406 ± 1 angstroms,
c
= 12.256 ± 1 angstroms, and space group
I
4
1
/a) has been refined by least-squares analysis to an
R
(discrepancy index) of 0.073. Two high-pressure phases of CaGeO
3
were synthesized, one isotypic with tetragonal CdGeO
3
(
a
= 12.514 ± 3 angstroms,
c
= 12.358 ± 3 angstroms), and the other isotypic with perovskite.
Operant Conditioning of Cortical Unit Activity
Authors: Fetz Eberhard E.
Published: October 2006

The activity of single neurons in precentral cortex of unanesthetized monkeys (
Macaca mulatta
) was conditioned by reinforcing high rates of neuronal discharge with delivery of a food pellet. Auditory or visual feedback of unit firing rates was usually provided in addition to food reinforcement. After several training sessions, monkeys could increase the activity of newly isolated cells by 50 to 500 percent above rates before reinforcement.
Freezing Resistance in Some Antarctic Fishes
Authors: DeVries Arthur L. , Wohlschlag Donald E.
Published: October 2006

Measurements of serum freezing points in three Antarctic marine fishes indicated that they do not freeze in the -1.87°C seawater because their blood is isosmotic to seawater. Concentrations of sodium chloride, urea, and free amino acids in the serum accounted for only half of the freezing-point depression of the serum. A protein containing carbohydrate was isolated which accounted for 30 percent of the freezing-point depression of the serum.
Recovery from Hemophilia B Leyden: An Androgen-Responsive Element in the Factor IX Promoter
Authors: Crossley Merlin , Ludwig Michael , Stowell Kathryn M. , De Vos Piet , Olek Klaus , Brownlee George G.
Published: October 2006

One form of the inherited, X-linked, bleeding disorder, hemophilia B, resolves after puberty. Mutations at -20 and -26 in the clotting factor IX promoter impair transcription by disrupting the binding site for the liver-enriched transcription factor LF-A1/HNF4. The -26 but not the -20 mutation also disrupts an androgen-responsive element, which overlaps the LF-A1/HNF4 site. This explains the improvement seen in patients with the -20 mutation and the failure of the -26 patient to recover.
Primate Type C Virus p30 Antigen in Cells from Humans with Acute Leukemia
Authors: Sherr Charles J. , Todaro George J.
Published: October 2006

Antigens related to the major structural protein (p30) of type C viruses isolated from a woolly monkey and a gibbon ape were found in peripheral white blood cells from five patients with acute leukemia.
Norepinephrine: Release from Brain by D-Amphetamine in vivo
Authors: Carr Laurence A. , Moore Kenneth E.
Published: October 2006

After injection of H
3
-norepinephrine into the left lateral cerebral ventricle of cats, the lateral and third cerebral ventricles were perfused with an artificial cerebrospinal fluid. Addition of
d
-amphetamine to the perfusion fluid caused a significant increase in the concentration of H
3
-norepinephrine in the effluent.
Toxoplasma gondii
: Fecal Forms Separated from Eggs of the Nematode
Toxocara cati
Authors: Frenkel J. K. , Dubey J. P. , Miller Nancy L.
Published: October 2006

Cats excreted the protozoan
Toxoplasma gondii
in feces, generally between 5 to 12 days after ingesting mice with chronic toxoplasmosis.
Toxoplasma gondii
and eggs of the nematode
Toxocara cati
occurring together could be separated by washing them through sieves that retained the eggs. This finding negates the postulated role of
Toxocara cati
in the transmission of toxoplasmosis.
Quantitative Electroencephalogram in Smoking and Smoking Deprivation
Authors: Ulett Judith A. , Itil Turan M.
Published: October 2006

After being deprived of cigarettes for 24 hours, eight young males who were heavy smokers showed significant changes in the electroencephalogram analyzed electronically and by digital computer. Compared to their records before smoking deprivation, there was a significant increase in slow frequencies. Resumed smoking reversed these trends.