bluuebunny/crossref_metadata_2025 huggingface dataset:
Oldest Known Terrestrial Arachnids
Authors: Størmer Leif
Published: October 2006

New finds of nonscorpionid arachnids in the Lower Devonian Nellenköpfchen Shale of Alken an der Mosel, Germany, give valuable information on the first appearance of terrestrial arachnids.
Feline Attractant,
cis
,
trans
-Nepetalactone: Metabolism in the Domestic Cat
Authors: Waller G. R. , Price G. H. , Mitchell E. D.
Published: October 2006

cis
,
trans
-Nepetalactone, the biologically active component of catnip, was force-fed to the domestic cat. When the
14
C-labeled compound was fed, 86 to 94 percent of the radioactivity was recovered in the urine, 1 to 2 percent was found in the feces, and 1 to 12 percent was collected as carbon dioxide. The major (50 to 75 percent) metabolite was α-nepetalinic acid, which was excreted in the urine together with small amounts of dihydronepetalactone, unchanged
cis
,
trans
-nepetalactone, and several unidentified compounds. No marked physiological or histological effects were observed when 20 to 80 milligrams of
cis
,
trans
-nepetalactone was administered orally. This is the first report on the metabolism of a mammalian attractant.
Collagen Gels: Design for a Vitreous Replacement
Authors: Stenzel Kurt H. , Dunn Michael W. , Rubin Albert L. , Miyata Teruo
Published: October 2006

Clear, stable gels have been prepared from purified tropocollagen from calf skin; the collagen was solubilized with a proteolytic enzyme (Proctase) and stabilized by ultraviolet irradiation under nitrogen. These gels are clear, possess altered immunologic reactivity, and have properties of an ideal vitreous replacement. Implantations in rabbit and monkey eyes appear to be well tolerated, remain clear, and gradually disappear in about 2 months.
Elastic Coefficients of Animal Bone
Authors: Lang Sidney B.
Published: October 2006

The elastic stiffness coefficients of dried bovine phalanx and femur and of fresh bovine phalanx were measured by an ultrasonic technique. An analysis of the crystallographic structure of the principal components of bone and its piezoelectric and pyroelectric behavior showed that bone is a texture that has the same elastic coefficient matrix as a hexagonal single crystal. The five elastic stiffness coefficients of fresh phalanx are:
C
11
, 1.97;
C
I2
, 1.21;
C
13
, 1.26;
C
33
, 3.20; and
C
44
, 0.54 (all in units of 10
11
dynes per square centimeter). Value of axial and transverse Young's and shear moduli, compressibility, and the three Poisson's ratios were calculated.
Enstatite: Disorder Produced by a Megabar Shock Event
Authors: Pollack Sidney S. , DeCarli Paul S.
Published: October 2006

Shocked Bamle enstatite partly transforms to disordered enstatite. Debye-Scherrer patterns of some shocked material are almost identical to those of disordered enstatite from portions of various enstatite achondrites. No disordered single crystals have been found.
Methane-Derived Marine Carbonates of Pleistocene Age
Authors: Hathaway John C. , Degens Egon T.
Published: October 2006

In some calcium carbonate-bearing sandstones from the edge of the continental shelf off the northeast United States, the δC
13
range is from -30 and -60 per mil for both aragonite and high-magnesium calcite. The δC
13
of coexisting shells of
Modiolus
sp. is normal (+ 1.7 to -2.7 per mil). The δO
18
values of around + 3.5 per mil in all samples suggest deposition at temperatures around 0°C. Quaternary methane oxidized either chemically or microbiologically to carbon dioxide is the probable source of carbon in these carbonates.
Interferon Induction Increased through Chemical Modification of a Synthetic Polyribonucleotide
Authors: De Clercq E. , Eckstein F. , Merigan T. C.
Published: October 2006

The alternating copolymer riboadenylic-ribouridylic acid gained a significant increase in ability to stimulate interferon production (2- to 20-fold) and cellular resistance (100- to 10,000-fold) both in vitro and in vivo upon substitution of phosphate by thiophosphate groups. The resulting nucleotide analog was also 10 to 100 times less sensitive to degradation by pancreatic ribonuclease, as determined by residual antiviral activity.
Related RNA Polymerase-binding Regions in Human RAP30/74 And
Escherichia coli
σ70
Authors: McCracken Susan , Greenblatt Jack
Published: October 2006

RAP30/74 is a heteromeric general transcription initiation factor that binds to mammalian RNA polymerase II. The RAP30 subunit contains a region that is similar in amino acid sequence to the RNA polymerase-binding domain of the
Escherichia coli
transcription initiation factor sigma 70 (σ70). Mammalian RNA polymerase II specifically protected a serine residue in the σ70-related region of RAP30 from phosphorylation in vitro. In addition, human RAP30/74 bound to
Escherichia coli
RNA polymerase and was displaced by σ70. These results suggest that RAP30 and σ70 have functionally related RNA polymerase-binding regions.
Glacier Oxygen-18 Content and Pleistocene Ocean Temperatures
Authors: Dansgaard W. , Tauber Henrik
Published: October 2006

The mean oxygen-18 content of continental ice sheets during the last glacial maximum is estimated to δO
18
=-30 per mille or less, and the consequent change in the isotopic composition of the oceans at that time to 1.2 per mille or more. This means that at least 70 percent of the oxygen-18 variations found in shells of planktonic foraminifera from deep-sea cores between times of glacial maximums and minimums are due to isotopic changes in ocean water, and at most 30 percent to changes in ocean surface temperature. Hence, Emiliani's "paleotemperature" curve rather depicts the amount of ice on the continents in excess of that present today. In this sense it may be renamed a "paleoglaciation" curve.
Oculomotor Neurons in Fish: Electrotonic Coupling and Multiple Sites of Impulse Initiation
Authors: Kriebel Mahlon E. , Bennett Michael V. L. , Waxman Stephen G. , Pappas George D.
Published: October 2006

Oculomotor neurons are electrotonically coupled in three teleosts. Electron microscopy revealed axosomatic synapses with close appositions of pre- and postynaptic membranes. Similar junctions are associated with electrotonic coupling in many other cases. Stimulation of the ipsilateral eighth nerve usually initiated impulses at sites distant from the cell bodies; stimulation of the ipsilateral ophthalmic nerve initiated impulses close to the cell bodies. Electrotonic coupling may synchronize impulses arising near the, cell bodies to generate synchronous muscle contractions. Impulses arising distant from the cell bodies may lead to contractions of graded strength.
Cell Sorting: Automated Separation of Mammalian Cells as a Function of Intracellular Fluorescence
Authors: Hulett H. R. , Bonner W. A. , Barrett Janet , Herzenberg Leonard A.
Published: October 2006

A system for high-speed sorting of fluorescent cells was able to sort mouse spleen cells from Chinese hamster ovarian cells after development of fluorochromasia. Highly fluorescent fractions separated after similar treatment from mouse spleen cells immunized to sheep erythrocytes were enriched in antibody-producing cells by factors of 4 to 10.
Mariners 6 and 7: Radio Occultation Measurements of the Atmosphere of Mars
Authors: Kliore Arvydas , Fjeldbo Gunnar , Seidel Boris L. , Rasool S. I.
Published: October 2006

Radio occultation measurements with Mariners 6 and 7 provided refractivity data in the atmosphere of Mars at four points above its surface. For an atmosphere consisting predominantly of carbon dioxide, surface pressures between 6 and 7 millibars are obtained at three of the points of measurement, and 3.8 at the fourth, indicating an elevation of 5 to 6 kilometers. The temperature profile measured by Mariner 6 near the equator in the daytime indicates temperatures in the stratosphere about 100°K warmer than those predicted by theory. The measurements of Mariner 6 taken at 79°N at the beginning of polar night indicate that conditions are favorable for the condensation of carbon dioxide at almost all altitudes. Mariner 7 measurements taken at 58°S in daytime and 38°N at night also show that carbon dioxide condensation is possible at altitudes above about 25 kilometers. Measurements of the electron density in the ionosphere show that the upper atmosphere is substantially warmer than it was in 1965, possibly because of increased solar activity and closer proximity to the sun.
Countercurrent Chromatography: Liquid-Liquid Partition Chromatography without Solid Support
Authors: Ito Yoichiro , Bowman Robert L.
Published: October 2006

The liquid-liquid partition chromatographic system reported here involves a long helix of narrow-bore tubing. When the coiled tube is filled with one phase of a two-phase system and fed with the other phase, phase-interchange takes place in each turn of the coil, leaving a segment of the former phase as the stationary phase. Consequently, solutes present in either phase are subjected to a multistep partition process. The column efficiency, estimated on a separation of dinitrophenyl amino acids, is comparable to that of gas chromatography.
Suspended Matter in Surface Waters of the Atlantic Continental Margin from Cape Cod to the Florida Keys
Authors: Manheim Frank T. , Meade Robert H. , Bond Gerard C.
Published: October 2006

Appreciable amounts of suspended matter (> 1.0 milligram per liter) in surface waters are restricted to within a few kilometers of the Atlantic coast. Particles that escape estuaries or are discharged by rivers into the shelf region tend to travel longshoreward rather than seaward. Suspended matter farther offshore, chiefly amorphous organic particles, totals 0.1 milligram per liter or less. Soot, fly ash, processed cellulose, and other pollutants are widespread.
Isotopic Composition of Rare Gases in Lunar Samples
Authors: Pepin R. O. , Nyquist L. E. , Phinney Douglas , Black David C.
Published: October 2006

Data from total melt and step-by-step heating experiments on the Apollo 11 lunar samples suggest a close affinity between lunar and meteoritic rare gases. Trapped neon-20/neon-22 ratios range from 11.5 to approximately 15, resembling those for the gas-rich meteorites. Trapped krypton and xenon in the lunar fines and in the carbonaceous chondrites are similar except for an interesting underabundance of the heavy isotopes in both lunar gases which suggests that the fission component found in carbonaceous chondrites is depleted in lunar material. Spallation gases are in most cases quite close to meteoritic spallation gases in isotopic composition.
Petrology of Unshocked Crystalline Rocks and Shock Effects in Lunar Rocks and Minerals
Authors: Chao E. C. T. , James Odette B. , Minkin Jean A. , Boreman Judith A. , Jackson E. D. , Raleigh C. B.
Published: October 2006

On the basis of rock modes, textures, and mineralogy, unshocked crystalline rocks are classified into a dominant ilmenite-rich suite (subdivided into intersertal, ophitic, and hornfels types) and a subordinate feldspar-rich suite (subdivided into poikilitic and granular types). Weakly to moderately shocked rocks show high strain-rate deformation and solid-state transformation of minerals to glasses; intensely shocked rocks are converted to rock glasses. Data on an unknown calcium-bearing iron metasilicate are presented.
Mössbauer Effect and High-Voltage Electron Microscopy of Pyroxenes in Type B Samples
Authors: Fernández-Morán H. , Hafner Stefan S. , Ohtsuki Mitsuo , Virgo David
Published: October 2006

Site occupancy numbers for ferrous iron, magnesium, and calcium at the M1 and M2 sites in lunar clinopyroxenes are estimated from nuclear gamma-ray resonant absorption spectra of
57
Fe. The cation distribution is ordered; calcium and magnesium prefer M2 and M1, respectively. The distribution corresponds to an equilibrium at a temperature lower than 680°C. Crystals cleaved and sectioned by diamond-knife ultramicrotomy were examined by high-voltage (200 kv) electron microscopy and diffraction. Uniform 300- to 600-Å-wide bands that correspond to single crystal domains were found. Correlation of the bands with magnetic ordering at low temperatures is considered.
Apollo 11 Drive-Tube Core Samples: An Initial Physical Analysis of Lunar Surface Sediment
Authors: Fryxell Roald , Anderson Daniel , Carrier David , Greenwood William , Heiken Grant
Published: October 2006

Two drive-tube core samples were obtained at Tranquillity Base. Fines include much glass, are unweathered, medium gray, loose, nonstructured, very weakly coherent, and demonstrate both accumulation and mixing in a waterless vacuum environment. In contrast to chemical weathering characteristic on the earth, lunar alteration processes are primarily mechanical. We infer that environmental processes of the lunar surface may be expressed as follows:
R
(regolith) =
f
(
cl
,
p
,
r
,
t
,
b
,
a
, . . .), in which climate (
cl
) is constant and the time (
t
)-de-pendent processes of bombardment (
b
) and accumulation (
a
) assume significance unparalleled on the earth because of their effects on parent material (
p
) and relief (
r
).
Astronomical Theory of Climatic Change: Support from New Guinea
Authors: Veeh H. Herbert , Chappell John
Published: October 2006

Radiocarbon and thorium-230 dates of uplifted coral reef terraces on New Guinea appear to support theories of glaciation which utilize Milankovitch cycles as a controlling trigger mechanism. In addition to high sealevel stands recognized by other workers, the New Guinea data clearly indicate a marine transgression between 50,000 and 35,000 years before the present. A eustatic sea level curve reconstructed from field observations and radiometric dates shows a close correlation with temperature fluctuations in high latitudes as predicted by astronomical data.
Toxoplasma gondii
in Cats: Fecal Stages Identified as Coccidian Oocysts
Authors: Frenkel J. K. , Dubey J. P. , Miller N. L.
Published: October 2006

Isospora
-type oocysts were excreted by cats following the ingestion of
Toxoplasma
from infected mice. Oocysts appeared 3 to 5 days after cysts were ingested and 8 to 10 days after trophozoites were ingested, and also 21 to 24 days after the administration of infective fecal suspensions from cats. A close quantitative and biologic correlation between oocysts and
Toxoplasma
infectivity of the feces was observed which could not be separated by density gradient centrifugation and filtration methods.
Toxoplasma
is an intestinal coccidian of cats which is fecally spread. It has evolved to multiply in brain and muscle and in other species, making it possible for carnivorism to become another means of transmission.
Neutrophils: Their Role in the Formation of a Tick Feeding Lesion
Authors: Tatchell R. J. , Moorhouse D. E.
Published: October 2006

Dogs infested with adult
Rhipicephalus sanguineus
were given nitrogen mustard to reduce leukocyte numbers. In the treated animals the tick lesions were insignificant, lacking the collagen destruction found in untreated hosts, but the ticks engorged normally. Feeding results from tick secretions causing vascular trauma and is independent of tissue damage associated with inflammatory responses.
Nonphotographic Alpha Autoradiography and Neutron-Induced Autoradiography
Authors: Becker Klaus , Johnson D. R.
Published: October 2006

With a new combination of two techniques, (i) alpha-particle or fission fragment registration in thin polymer foils by etching and (ii) automatic counting and magnification of the etched perforations by local evaporation of a thin metal layer with an electric spark, the sensitivity of conventional photographic methods for determining quantity and spatial distribution of alpha emitters, fissile materials, and of elements undergoing (n, α) reactions can be drastically improved, without need for darkroom processing and microscopic evaluation.
Recoverin: a Calcium Sensitive Activator of Retinal Rod Guanylate Cyclase
Authors: Dizhoor Alexander M. , Ray Sanghamitra , Kumar Santosh , Niemi Greg , Spencer Maribeth , Brolley Doane , Walsh Kenneth A. , Philipov Paul P. , Hurley James B. , Stryer Lubert
Published: October 2006

Vertebrate retinal photoreceptors recover from photoexcitation-induced hydrolysis of guanosine 3′, 5′-monophosphate (cyclic GMP) by resynthesizing cyclic GMP, which reopens cation channels that have been closed by light. Activation of guanylate cyclase by light-induced depletion of cytosolic calcium is a key event in this recovery process. This cyclase has now been shown to be regulated by a 23-kilodalton calcium binding protein. The protein is present in both rod and cone photoreceptors and was named recoverin because it promotes recovery of the dark state. The amino acid sequence of recoverin exhibits three potential calcium binding sites (EF hands). That recoverin binds calcium was confirmed with calcium-45 and by observing calcium-induced changes in its tryptophan fluorescence. Recoverin activated guanylate cyclase when free calcium was lowered from 450 to 40 nM, an effect that was blocked by an antibody to recoverin. Thus, guanylate cyclase in retinal rods is stimulated during recovery by the calcium-free form of recoverin. A comparison of recoverin with other calcium binding proteins reveals that it may represent, along with the protein visinin, a family of proteins that are regulated by submicromolar calcium concentrations.
Selective Activation of the B Natriuretic Peptide Receptor by C-Type Natriuretic Peptide (CNP)
Authors: Koller Kerry J. , Lowe David G. , Bennett Gregory L. , Minamino Naoto , Kangawa Kenji , Matsuo Hisayuki , Goeddel David V.
Published: October 2006

The natriuretic peptides are hormones that can stimulate natriuretic, diuretic, and vasorelaxant activity in vivo, presumably through the activation of two known cell surface receptor guanylyl cyclases (ANPR-A and ANPR-B). Although atrial natriuretic peptide (ANP) and, to a lesser extent, brain natriuretic peptide (BNP) are efficient activators of the ANPR-A guanylyl cyclase, neither hormone can significantly stimulate ANPR-B. A member of this hormone family, C-type natriuretic peptide (CNP), potently and selectively activated the human ANPR-B guanylyl cyclase. CNP does not increase guanosine 3′,5′-monophosphate accumulation in cells expressing human ANPR-A. The affinity of CNP for ANPR-B is 50- or 500-fold higher than ANP or BNP, respectively. This ligand-receptor pair may be involved in the regulation of fluid homeostasis by the central nervous system.
Metabolite of (—)-
trans
-Δ
8
-Tetrahydrocannabinol: Identification and Synthesis
Authors: Foltz R. L. , Fentiman A. F. , Leighty E. G. , Walter J. L. , Drewes H. R. , Schwartz W. E. , Page T. F. , Truitt E. B.
Published: October 2006

The major metabolite of (—)-
trans
-Δ
8
-tetrahydrocannabinol observed in vivo and formed by hepatic microsomes in vitro is 11-hydroxy-
trans
-Δ
8
-tetrahydrocannabinol. The metabolite was identified spectroscopically and was synthesized from
trans
-Δ
8
-tetrahydrocannabinol. In tests with rats, the metabolite produced behavioral effects similar to those imparted by Δ
8
- and Δ
9
-tetrahydrocannabinol.
Australopithecine Endocast (Taung Specimen, 1924): A New Volume Determination
Authors: Holloway Ralph L.
Published: October 2006

A redetermination of endocranial volume of the original 1924 Taung australopithecine described by Dart indicates a volume of 405 cubic centimeters, rather than the 525 cubic centimeters published earlier. The adult volume is estimated to have been 440 cubic centimeters. This value, plus other redeterminations of australopithecine endocasts, lowers the average to 442 cubic centimeters, and increase the likelihood of statistically significant differences from both robust australopithecines and the Olduvai Gorge hominid No. 7.
Circadian Rhythm of Brain Self-Stimulation Behavior
Authors: Terman Michael , Terman Jiuan S.
Published: October 2006

Under constant conditions of light, sound, temperature, and humidity, rats exhibited circadian rhythmicity in rate of bar-pressing with hypothalamic and septal reinforcing brain stimulation. Variations in reinforcer magnitude aflected absolute levels of operant response emission but not the frequency of the circadian rhythm. In long sessions, the time of peak responding deviated systematically from a strict 24-hour period. Such data show marked similarity to free-running rhythms of motor activity.
Phycomyces
: Habituation of the Light Growth Response
Authors: Ortega Joseph K. E. , Gamow Rustem Igor
Published: October 2006

Phycomyces
sporangiophores respond to four distinct physical stimuli: gravity, light, stretch, and an avoidance stimulus. Saturating the organism with a light stimulus so that it does not respond to any additional light program does not decrease its ability to respond to an avoidance stimulus. This demonstrates that the organism has the potential to respond after a saturating light stimulus and that the avoidance stimulus acts at some point past or parallel to the light-receiving mechanism.
Chlorophyll Derivatives in Middle Eocene Sediments
Authors: Dilcher David L. , Pavlick Raphael J. , Mitchell James
Published: October 2006

Chloroform extracts of middle Eocene brown coal were made; the chlorophyll derivatives obtained were separated chromatographically. The visible light spectrum, chromatographic behavior, HCl number, infrared spectrum, and mass spectrum of one of the pigments extracted is indicative of methyl pheophorbide a. This is the oldest occurrence of fossil phorbins reported.
Copulatory Behavior Can Inhibit Pregnancy in Female Rats
Authors: Adler N. T. , Zoloth S. R.
Published: October 2006

If female rats received genital stimulation soon enough after their male partners had ejaculated, sperm transport and subsequent pregnancy were inhibited. Manual stimulation by the experimenter or five intromissions by a male rat were sufficient stimuli to reduce the number of sperm found in the uterus and to reduce the number of uterine implantation sites.
Brain Adenosine Triphosphate: Decreased Concentration Precedes Convulsions
Authors: Sanders Aaron P. , Kramer Richard S. , Woodhall Barnes , Currie William D.
Published: October 2006

The concentration of adenosine triphosphate in the brain decreased before the onset of generalized convulsions in unanesthetized rats subjected to acute hypoxia or treated with hydroxylamine or pentylenetetrazole (Metrazol). As the convulsive episode continued, adenosine triphosphate decreased further. Stimulation of adenosine triphosphate production forestalled its disappearance from the brain and delayed the development of seizure activity.
Caldera Collapse in the Galápagos Islands, 1968
Authors: Simkin Tom , Howard Keith A.
Published: October 2006

The summit caldera of Isla Fernandina, a large, uninhabited basaltic shield volcano, was further enlarged by 1 to 2 km
3
in June 1968. A small quake and large vapor cloud on 11 June were followed 4 hours later by a remarkable volcanic ash cloud and, after another hour, by a major explosion recorded at infrasonic stations throughout the hemisphere. Seismic activity increased to a peak on 19 June, when more than 200 events per day were recorded by a seismograph 140 km away. Several hundred quakes were in the magnitude range 4.0 to 5.4

m
b

, but few such events were recorded after 23 June. Unusual lightning accompanied the major cloud, and, during the evening of 11 June, distant observers reported red glow and flashes from the area. Fine ash fell that night and much of the next day to distances at least 350 km from the volcano.
T Cell Reactivity to MHC Molecules: Immunity Versus Tolerance
Authors: Sprent Jonathan , Gao Er-Kai , Webb Susan R.
Published: October 2006

The specificity of mature CD8
+
and CD4
+
T lymphocytes is controlled by major histocompatibility complex (MHC) class I and class II molecules, respectively. The MHC class specificity of T cells is stringent in many assays, but is less evident when cells are supplemented with exogenous lymphokines. The repertoire of T cells is shaped through contact with MHC molecules in the thymus and involves a complex process of positive selection and negative selection (tolerance). Tolerance of immature T cells to MHC molecules can reflect either clonal deletion or anergy and results from intrathymic contact with several cell types, including epithelial cells and cells with antigen-presenting function. Unlike immature T cells, mature T cells are relatively resistant to tolerance induction. In certain situations partial unresponsiveness of mature T cells can be achieved by exposing T cells to foreign MHC molecules expressed on atypical antigen-presenting cells. Tolerance is rarely complete, however, and the precise requirements for tolerizing mature T cells are still unclear.
Temporal Summation Phenomena at Threshold: Their Relation to Visual Mechanisms
Authors: Zacks James L.
Published: October 2006

Threshold energies were determined for brief flashes as a function of their duration in order to determine the maximum duration for which the flash intensity and duration could be varied reciprocally without affecting detectability (the Bunsen-Roscoe effect). A pair of threshold-level flashes for which reciprocity obtained in the determination of threshold were shown to be discriminable from each other at several imperfectly detectable energy levels. Thus equal detectability of flashes of equal energy does not imply identical neural responses to such stimuli. It is suggested that the summation reflects primarily the operation of the detection mechanism rather than of the peripheral visual mechanism. Some general implications for the interpretation of threshold measures are also discussed.
Electrical Coupling: Low Resistance Junctions between Mitotic and Interphase Fibroblasts in Tissue Culture
Authors: O'Lague Paul , Dalen Helge , Rubin Harry , Tobias Cornelius
Published: October 2006

Dividing cells of chick embryonic fibroblasts and of mouse embryonic fibroblasts (3T3) in tissue culture are electrically coupled to their interphase neighbors. Recordings from many such cells suggest that this coupling persists throughout the division cycle of the mitotic cell.
Shear Degradation of Fibrinogen in the Circulation
Authors: Charm Stanley E. , Wong Bing Low
Published: October 2006

Plasma fibrinogen in vitro suffers a loss in clottability due to shearing. From calculation of the mass average shear to which plasma is subjected in the circulation, it is estimated that the half-life of fibrinogen is 4 days. This is in excellent agreement with reports that the half-life of fibrinogen in the circulatory system is 4 to 5 days. Hence shearing may be the mechanism for fibrinogen degradation in the circulatory system.
Archaeopteryx: Notice of a "New" Specimen
Authors: Ostrom John H.
Published: October 2006

A fourth specimen of
Archaeopteryx
(cf.
lithographica
), the oldest known fossil bird, was recently found in the collections of the Teyler Museum in the Netherlands. Unique preservation of the horny sheaths of the manus claws provides new evidence that may be relevant to the question of the origins of avian flight. Tentative interpretation suggests a cursorial rather than arboreal origin.
Mechanism for the Water-to-Air Transfer and Concentration of Bacteria
Authors: Blanchard Duncan C. , Syzdek Lawrence
Published: October 2006

Air bubbles breaking at the air-water interface can remove bacteria that concentrate in the surface microlayer and eject the bacteria into the atmosphere. The bacterial concentrations (numbers per milliliter) in the drops ejected from the bubbles may, depending on drop size, be from 10 to 1000 times that of the water in which the bubbles burst.
Tolerance to Morphine-Induced Increases in [
14
C]Catecholamine Synthesis in Mouse Brain
Authors: Smith Charles B. , Villarreal Julian E. , Bednarczyk Janet H. , Sheldon Murray I.
Published: October 2006

Morphine sulfate increased the incorporation of carbon-14-labeled tyrosine into labeled catecholamines in the mouse brain. Tolerance was manifested by a shift to the right in the dose-response curve for morphine after mice were treated repeatedly with morphine. Naloxone, a specific morphine antagonist, also shifted the dose-response curve for morphine to the right.
Parkinson's Disease: Activity of L-Dopa Decarboxylase in Discrete Brain Regions
Authors: Lloyd K. , Hornykiewicz O.
Published: October 2006

The activity of L-dopa decarboxylase was greatly reduced in the striatum, less so in the hypothalamus, and unchanged in the cortex of brains of patients with Parkinson's disease. However, it appears that even in the striatum enough activity remained to allow for the formation of dopamine from L-dopa in patients treated with large doses of L-dopa.
A Multisubunit Ribozyme That Is a Catalyst of and Template for Complementary Strand RNA synthesis
Authors: Doudna Jennifer A. , Couture Sandra , Szostak Jack W.
Published: October 2006

Derivatives of the
sunY
self-splicing intron efficiently catalyzed the synthesis of complementary strand RNA by template-directed assembly of oligonucleotides. These ribozymes were separated into three short RNA fragments that formed active catalytic complexes. One of the multisubunit
sunY
derivatives catalyzed the synthesis of a strand of RNA complementary to one of its own subunits. These results suggest that prebiotically synthesized oligonucleotides might have been able to assemble into a complex capable of self-replication.
Amorphous Ice: Density and Reflectivity
Authors: Ghormley J. A. , Hochanadel C. J.
Published: October 2006

Amorphous ice prepared under a wide range of conditions has a density, determined from its buoyancy in liquid oxygen, of 0.94 ± 0.02 gram per cubic centimeter, the same as that of ordinary hexagonal ice, with no indication of the glassy superdense ice (2.32 grams per cubic centimeter) reported recently. The diffuse reflectivity shows a small increase as the ice crystallizes at 153°K. This increase is followed by a much larger increase (probably associated with crystal growth) as the sample warms, and the reflectivity reaches a maximum well below the melting temperature. Although the ice deposits appear translucent, the specular reflectivity is low, thus indicating a dull rather than a glassy surface.
DDT: Participation in Ultraviolet-Detectable, Charge-Transfer Complexation
Authors: Wilson W. E. , Fishbein L. , Clements S. T.
Published: October 2006

The chlorophenyl groups of DDT and several of its metabolites are capable of participating in a charge-transfer interaction with tetracyanoethylene detectable in the ultraviolet region of the spectrum. In addition, during a change of state DDT undergoes ultraviolet spectral alterations that closely resemble those previously claimed to support the hypothesis suggesting charge-transfer interaction between this pesticide and a component of insect nerve tissue. The pesticide DDT possesses structural characteristics that would permit it to participate in several types of molecular association.
Arguments Concerning Relativity and Cosmology
Authors: Klein Oskar
Published: October 2006

In the first place I have reviewed the true foundation of Einstein's theory of general relativity, the so-called
principle of equivalence
, according to which there is no essential difference between "genuine" gravitation and inertial forces, well known from accelerated vehicles. By means of a comparison with Gaussian geometry of curved surfaces—the background of Riemannian geometry, the tool used by Einstein for the mathematical formulation of his theory—it is made clear that this principle is incompatible with the idea proposed by Mach and accepted by Einstein as an incitement to his attempt to describe the main situation in the universe as an analogy in three dimensions to the closed surface of a sphere. In the later attempts toward a mathematical description of the universe, where Einstein's cosmology was adapted to the discovery by Hubble that its observed part is expanding, the so-called cosmological postulate has been used as a kind of axiomatic background which, when analyzed, makes it probable that this expansion is shared by a very big, but still bounded system. This implies that our expanding metagalaxy is probably just one of a type of stellar objects in different phases of evolution, some expanding and some contracting. Some attempts toward the description of this evolution are sketched in the article with the hope that further investigation, theoretical and observational, may lead to an interesting advance in this part of astrophysics.
Aflatoxin P
1
: A New Aflatoxin Metabolite in Monkeys
Authors: Dalezios John , Wogan Gerald N. , Weinreb Steven M.
Published: October 2006

A new phenolic derivative of aflatoxin B
1
, appearing mainly in conjugated form, was identified as the principal urinary metabolite of aflatoxin B
1
in rhesus monkeys. Its identification in human urine might facilitate estimation of aflatoxin exposure in human populations.
Sex Pheromone of the Almond Moth and the Indian Meal Moth:
cis
-9,
trans
-12-Tetradecadienyl Acetate
Authors: Kuwahara Y. , Kitamura C. , Takashi S. , Hara H. , Ishii S. , Fukami H.
Published: October 2006

Female moths of different species but belonging to the same subfamily produce an identical compound as their sex pheromone. The sex pheromone of the almond moth,
Cadra cautella
(Walker), and the Indian meal moth,
Plodia interpunctella
(Hübner), has been isolated and identified as
cis
-9,
trans
-12-tetradecadienyl acetate.
Classical Conditioning of a Complex Skeletal Response
Authors: Gamzu Elkan , Williams David R.
Published: October 2006

The pigeon's so-called "arbitrary" response of pecking an illuminated disk can be established and maintained by procedures resembling those of classical conditioning. This phenomenon was shown to be independent of the specific signaling relationships between illumination of the pecking disk and presentation of food; it will appear as long as the key is differentially associated with food. When a nondifferential condition is introduced, pecking "extinguishes" even if it has previously been established and even when the new condition involves as much reinforcement as the old one. Reinstating differential conditions reestablishes pecking. The initial conditions determine the speed and apparently the asymptote of pecking rates in the differential condition; initial exposure to a nondifferential procedure retards subsequent acquisition, possibly quite permanently. These findings are discussed in the context of mechanisms of adaptive learning, not involving reward and punishment, which lead to selection of effective behaviors on a nonarbitrary basis.
Long-Range Structure in Ribonuclease P RNA
Authors: Haas Elizabeth S. , Morse Daniel P. , Brown James W. , Schmidt Francis J. , Pace Norman R.
Published: October 2006

Phylogenetic-comparative and mutational analyses were used to elucidate the structure of the catalytically active RNA component of eubacterial ribonuclease P (RNase P). In addition to the refinement and extension of known structural elements, the analyses revealed a long-range interaction that results in a second pseudoknot in the RNA. This feature strongly constrains the three-dimensional structure of RNase P RNA near the active site. Some RNase P RNAs lack this structure but contain a unique, possibly compensating, structural domain. This suggests that different RNA structures located at different positions in the sequence may have equivalent architectural functions in RNase P RNA.
Behavioral Sensitivity to Microwave Irradiation
Authors: King Nancy Williams , Justesen Don R. , Clarke Rex L.
Published: October 2006

Rats assayed by the technique of conditional suppression were able to detect the presence of 12.25-centimeter microwaves at doses of power approximating 0.5 to 6.4 milliwatts per gram. The assay, which controlled for sensitization, for pseudo and temporal conditioning, and for several possible sources of artifactual cueing, revealed that irradiation by microwaves, although lacking the saliency of an auditory stimulus, can function as a highly reliable cue. Efficiency of detection was strongly and positively related to the amount of microwave energy to which the rats were exposed.
Butterfly-Plant Coevolution: Has
Passiflora adenopoda
Won the Selectional Race with Heliconiine Butterflies?
Authors: Gilbert Lawrence E.
Published: October 2006

Hooklike trichomes of
Passiflora adenopoda
provide a specific, effectively absolute defense against heliconiine butterfly larvae, a major class of
Passiflora
herbivores. It is suggested that since mechanical defenses are usually more selective in their action against herbivores, they usually are evolved by a plant only after it has accumulated a series of chemical defenses.
Allende Meteorite: A High-Voltage Electron Petrographic Study
Authors: Green H. W. , Radcliffe S. V. , Heuer A. H.
Published: October 2006

Electron-transparent sections of the Allende meteorite, a carbonaceous chondrite, have been prepared by ion-thinning and examined by high-voltage (800-kilovolt) transmission electron microscopy. The matrix crystals, mainly olivine, range in size from approximately 5 to approximately 0.01 micrometers; carbon is present as intergranular films of poorly crystalline graphite. The chondrules exhibit extensive radiation damage, a feature lacking in the matrix. In addition, both chondrules and matrix are undeformed and contain negative crystals; submicroscopic exsolution lamellae are present in pyroxenes. Comparison of the substructure in the Allende meteorite with that in the Parnallee meteorite and in lunar and selected terrestrial rocks leads to the conclusion that chondrule irradiation preceded cold accretion during formation of the solar system and that the meteorite has since been undisturbed.
Ultraviolet Light: A New Stimulus for the Induction of Platelet Aggregation
Authors: Dickson R. C. , Doery J. C. G. , Lewis A. F.
Published: October 2006

Exposure to ultraviolet light (253.7 nanometers) causes mammalian blood platelets to aggregate. Aggregation is markedly enhanced in the presence of extracellular fibrinogen and is followed by the gradual release of relatively small amounts of nucleotide and serotonin. Aggregation is inhibited by ethylenediamine tetraacetic acid or a combination of 2-deoxy-D-glucose and antimycin A. Adenosine, apyrase, and prostaglandin E
1
produced slight inhibition. The effect of exposure to ultraviolet light is cumulative and lasting. This agent may be used to study the process of platelet aggregation after the removal of the stimulus, by delaying the addition of fibrinogen until after cessation of irradiation. Thus ultraviolet light is the first agent known which may be used to study platelet aggregation in a period following its removal.
Magnesium-Iron Replacement in Clay Minerals in Anoxic Marine Sediments
Authors: Drever James I.
Published: October 2006

In anoxic marine sediments iron is extracted from clay minerals to form a sulfide. Magnesium from the surrounding solution then replaces the extracted iron in the clay mineral structure. This process removes magnesium from seawater and serves as a control on the composition of interstitial waters in sediments.
Biological Activity and Synthesis of an Encephalitogenic Determinant
Authors: Shapira R. , Chou F. C-H. , McKneally S. , Urban E. , Kibler R. F.
Published: October 2006

A 45-residue fragment of the basic protein of myelin is encephalitogenic in the rabbit and monkey but relatively inactive in the guinea pig. Synthetic peptides containing the sequence of a tryptic peptide of the fragment Thr-Thr-His-Tyr-Gly-Ser-Leu-Pro-Gln-Lys are moderately encephalitogenic.
Stability and Diversity at Three Trophic Levels in Terrestrial Successional Ecosystems
Authors: Hurd L. E. , Mellinger M. V. , Wolf L. L. , McNaughton S. J.
Published: October 2006

An ecosystem perturbation experiment in which inorganic fertilizer was added to two successional old fields of different ages indicated that stability, expressed as resistance to modification by enrichment, increased during succession only at the primary trophic level. The perturbation was propagated throughout the arthropod herbivores and carnivores. Both herbivores and carnivores were less stable in the older field. In contrast to current ecological theory, greater diversity at a trophic level was accompanied by lower stability at the next higher level.
Talc-Treated Rice and Japanese Stomach Cancer
Authors: Merliss R. R.
Published: October 2006

The Japanese prefer talc-dusted rice in their diet. The incidence of stomach cancer in Japan is unusually high. Most talc has some asbestos contaminants. Epidemiologic evidence is presented that the asbestos-contaminated talc on rice in the diet is the carcinogen or cocarcinogen responsible for the high incidence of Japanese stomach cancer.
Potentially Amyloidogenic, Carboxyl-Terminal Derivatives of the Amyloid Protein Precursor
Authors: Estus Steven , Golde Todd E. , Kunishita Tatsuhide , Blades Deborah , Lowery David , Eisen Matthew , Usiak Marianne , Qu Xuemei , Tabira Takeshi , Greenberg Barry D , Younkin Steven G.
Published: October 2006

The 39- to 43-amino acid amyloid β protein (βAP), which is deposited as amyloid in Alzheimer's disease, is encoded as an internal peptide that begins 99 residues from the carboxyl terminus of a 695- to 770-amino acid glycoprotein referred to as the amyloid β protein precursor (βAPP). To clarify the processing that produces amyloid, carboxyl-terminal derivatives of the βAPP were analyzed. This analysis showed that the βAPP is normally processed into a complex set of 8- to 12-kilodalton carboxyl-terminal derivatives. The two largest derivatives in human brain have the entire βAP at or near their amino terminus and are likely to be intermediates in the pathway leading to amyloid deposition.
Intercalation Complexes of Lewis Bases and Layered Sulfides: A Large Class of New Superconductors
Authors: Gamble F. R. , Osiecki J. H. , Cais M. , Pisharody R. , DiSalvo F. J. , Geballe T. H.
Published: October 2006

Exploration of the generality of the recently discovered reaction whereby certain organic molecules can be inserted between the metallic layers of the superconductors tantalum disulfide and niobium disulfide revealed that a large variety of organic and inorganic molecules can penetrate between the crystalline layers of a number of transition metal dichalcogenides and that the resulting complexes are superconducting if the layered chalcogenide from which they are formed is superconducting. The critical temperatures of the 50 new superconductors we report depend on the nature of the intercalate but are insensitive to a separation of the superconducting planes of up to 57 angstroms.
Polymorphism of Human Constitutive Heterochromatin
Authors: Craig-Holmes Ann P. , Shaw Margery W.
Published: October 2006

Genetic polymorphism has been demonstrated in man for many characteristics including blood groups, serum proteins, tissue enzymes, and hemoglobins. A class of chromosomal polymorphism involving constitutive heterochromatin has now been found. Through the use of a special technique that permits visualization of heterochromatin, seven heterochromatin variants have been found among four individuals. These results suggest a very high frequency of variability of heterochromatin in the population.
DNA Constancy in Heteroploidy and the Stem Line Theory of Tumors
Authors: Kraemer Paul M. , Petersen D. F. , Van Dilla M. A.
Published: October 2006

Cellular DNA was measured by high-speed flow microfluorometry in mammalian diploid and heteroploid cell populations stained by the fluorescent-Feulgen procedure. Heteroploid cells with elevated modal chromosome number showed the expected increase in modal DNA content. However, the variability of DNA content was the same in diploid and heteroploid cell populations despite the large variability of chromosome number in the latter populations. This suggests that heteroploidy may include defects in the chromosomal condensation and kinetochore development systems.
Cloning and Expression of the cDNA for Human γ-glutamyl Carboxylase
Authors: Wu Sheue-Mei , Cheung Wing-Fai , Frazier Dan , Stafford Darrel W.
Published: October 2006

The cDNA for human γ-glutamyl carboxylase, which accomplishes the post-translational modification required for the activity of all of the vitamin K-dependent proteins, was cloned. The enzyme is a 758-residue integral membrane protein and appears to have three transmembrane domains near its amino terminus. The hydrophilic COOH-terminal half of the carboxylase has 19.3 percent identity with soybean seed lipoxygenase. Expression of the cloned cDNA resulted in an increase in carboxylase activity in microsomes of transfected cells compared to mock-transfected cells.
Alpha
1
Antitrypsin in the Livers of Patients with Emphysema
Authors: Lieberman Jack , Mittman Charles , Gordon Herschel W.
Published: October 2006

Parenchymal liver cells from emphysema patients with an inherited deficiency of α
1
-antitrypsin contain globules of glycoprotein that bind fluorescent antibody to α
1
-antitrypsin. The globules can be seen after hematoxylin and eosinstaining or on electron microscopy, but are more readily demonstrated by PAS stain of amylase-treated liver sections. It appears that an inappropriately large amount of α
1
-antitrypsin is found in the liver even when there is a deficiency in the serum. Genetic variants of the normal antitrypsin molecule may be unable to leave their site of synthesis in the liver cell because of some molecular aberration.
Theta Rhythm: A Temporal Correlate of Memory Storage Processes in the Rat
Authors: Landfield Philip W. , McGaugh James L. , Tusa Ronald J.
Published: October 2006

We examined the amount of theta rhythm (4 to 9 hertz) in cortical electroencephalograms of rats for 30 minutes after training in one-trial tasks. Some animals received electroconvulsive shock after training. The amount of theta in the electroencephalogram after training was positively correlated with the degree of subsequent retention of a footshock, whether animals had received electroconvulsive shock or not.
Cavernicoles in Lava Tubes on the Island of Hawaii
Authors: Howarth Francis G.
Published: October 2006

Cave-adapted arthropods have evolved in lava tubes in Hawaii. This is the first report of cavernicoles from the Hawaiian islands. The specialization of the cavernicolous insects and the recent origin of the lava tubes suggest that subterranean connections between lava tubes regularly occur and provide dispersal routes. The discovery that lava tubes were colonized by representatives of the adaptively radiating native fauna offers significant potential for evolutionary studies.
Lystrosaurus Zone (Triassic) Fauna from Antarctica
Authors: Kitching James W. , Collinson James W. , Elliot David H. , Colbert Edwin H.
Published: October 2006

Tetrapod skeletons recently found in the Fremouw Formation in the Shackleton Glacier area, Transantarctic Mountains, include several forms that closely compare to South African species. Faunal similarities that confirm a close connection between Antarctica and Africa during the Triassic Period lend further support to the concept of Gondwanaland and continental drift.
Crystalline Cholera Toxin and Toxoid
Authors: Finkelstein Richard A. , LoSpalluto Joseph J.
Published: October 2006

The exo-enterotoxin of
Vibrio cholerae
has been obtained in crystalline form. A solution of the crystalline protein was equal in potency to the parent pure toxin in both choleragenicity and skin reactivity. Crystals of the natural toxoid, choleragenoid, resemble those of the toxin in appearance. A solution of crystalline choleragenoid was equivalent to the parent preparation in the flocculation test.
Calcium Hydroxide: Its Role in the Fracture of Tricalcium Silicate Paste
Authors: Berger Richard L.
Published: October 2006

The large areas of crystalline calcium hydroxide [Ca(OH)
2
] formed during the hydration of tricalcium silicate (Ca
3
SiO
5
) correspond to low-porosity regions in the hydrated paste. During the early stage of hydration, areas between Ca(OH)
2
crystals which consist of Ca
3
SiO
5
particles bonded together by calcium silicate hydrate represent the high-porosity portion of the paste. Because of the presence of Ca(OH)
2
, fracture in the hardened paste during this period propagates preferentially through the areas bonded by the calcium silicate hydrate phase and around the Ca(OH)
2
, crystals. Calcium hydroxide also acts as a crack arrester. The influence of Ca(OH)
2
on fracture diminishes with increased hydration.