bluuebunny/crossref_metadata_2025 huggingface dataset:
β-Galactosidase and Selective Neutrality
Authors: Holmquist Richard
Published: October 2006

Three hypotheses to explain the amino acid composition of proteins are inconsistent (P ≅ 10
-9
) with the experimental data for β-galactosidase from Escherichia coli. The exceptional length of this protein, 1021 residues, permits rigorous tests of these hypotheses without complication from statistical artifacts. Either this protein is not at compositional equilibrium, which is unlikely from knowledge about other proteins, or the evolution of this protein and its coding gene have not been selectively neutral. However, the composition of approximately 60 percent of the molecule is consistent with either a selectively neutral or nonneutral evolutionary process.
Thalamic and Cortical Afferents Differentiate Anterior from Posterior Cingulate Cortex in the Monkey
Authors: Vogt Brent A. , Rosene Douglas L. , Pandya Deepak N.
Published: October 2006

The anterior cingulate cortex receives thalamic afferents mainly from the midline and intralaminar nuclei rather than the anterior thalamic nuclei. In contrast, the posterior cingulate cortex receives afferents primarily from the anterior thalamic nuclei and from extensive cortical areas in the frontal, parietal, and temporal lobes. These contrasting afferents may provide a structural basis for pain-related functions of the anterior cingulate cortex.
Glucagon Release: Paradoxical Stimulation by Glucose During Calcium Deprivation
Authors: Leclercq-Meyer Viviane , Rebelledo Oscar , Marchand Jocelyne , Malaisse Willy J.
Published: October 2006

During calcium deprivation, the rate of glucagon release by the isolated perfused rat pancreas is positively related to the glucose concentration of the perfusion medium. It is suggested that such a paradoxical behavior, which is reminiscent of the abnormality of glucagon secretion recently disclosed in diabetic subjects, results from a perturbation in the normal structural and functional bridging between pancreatic alpha and beta cells.
Orientation Anisotropy of Visual Stimuli in Rhesus Monkey: a Behavioral Study
Authors: Boltz Roger L. , Harwerth Ronald S. , Smith Earl L.
Published: October 2006

The contrast sensitivity of the rhesus monkey was tested, according to a modified reaction-time paradigm, for sine-wave grating targets at different orientations. The monkey possesses an oblique effect slightly larger than that of humans. A reaction time analysis showed the oblique effect to be a suprathreshold as well as a threshold phenomenon. The presence of this effect further strengthens the use of the monkey as a model for the human visual system.
Visual Construction of Color Is Digital
Authors: Kolers Paul A. , von Grunau Michael
Published: October 2006

When disparate shapes are flashed under the appropriate temporal and spatial conditions, the human visual system resolves their disparity smoothly and continuously. No equivalent supplementations are found for color, which the system resolves by abrupt transformation. Shape and color reveal themselves, contrary to some modern theorizing, as properties handled in different ways by the visual nervous system, continuous or analog for shape, abrupt or digital for color.
Trichlorofluoromethane in the Troposphere, Distribution and Increase, 1971 to 1974
Authors: Wilkniss P. E. , Swinnerton J. W. , Lamontagne R. A. , Bressan D. J.
Published: October 2006

Trichlorofluoromethane (CCl
3
F) measurements in the troposphere over the Atlantic in 1971 and over the Pacific in 1972 and 1974 were compared. A rapid increase of CCl
3
F in the troposphere is evident. The observed increase of CCl
3
F between 1971 and 1974 is proportional to the increase of industrially produced amounts of CCl
3
F in the same time period.
Laser Raman Spectroscopy—New Probe of Myosin Substructure
Authors: Carew E. Bayne , Asher Irvin M. , Stanley H. Eugene
Published: October 2006

Laser Raman spectroscopy is used to probe the heterogeneous substructure of the large contractile protein myosin. Some peaks are assigned to specific chemical groups of the molecule; others, notably the conformationally sensitive amide III vibrations, provide information on the structurally distinct regions of the molecule. Deuteration of the NH groups is instrumental in the assignment of these vibrational modes. The relative intensities of bands typical of α-helical conformations (near 1265 and 1304 cm
-1
) and bands associated with nonhelical structure (near 1244 cm
-1
) are sensitive indicators of myosin substructure and represent potentially useful probes of conformational changes.
Juvenile Hormone Analogs: Detrimental Effects on the Development of an Endoparasitoid
Authors: McNeil Jeremy
Published: October 2006

A high incidence of mortality of the endoparasitoid
Aphidius nigripes
was observed when its host.
Macrosiphum euphorbiae
, was treated with juvenile hormone analogs. Larval and pupal stages of the parasitoid were susceptible. Off-target effects on natural enemies may seriously limit the use of juvenile hormone analogs, especially in integrated control programs.
Structure of Coat Proteins in Pf1 and fd Virions by Laser Raman Spectroscopy
Authors: Thomas G. F. , Murphy P.
Published: October 2006

Raman spectra of filamentous bacterial viruses are dominated by scattering from vibrations of the protein capsomers. The amino acid compositions of coat proteins in Pf1 and fd strains are recognized by their different side-chain vibrational frequencies. However, the conformationally sensitive amide frequencies indicate that Pf1 and fd coat proteins have the same α-helical secondary structures. Viral DNA backbones do not exhibit the A-type geometry.
Epidermal Growth Factor: Identification of a New Hormone in Human Urine
Authors: Starkey Ralph H. , Cohen Stanley , Orth David N.
Published: October 2006

Epidermal growth factor is a polypeptide hormone that was previously identified only in mice. It causes proliferation and keratinization of epidermal tissues. An immune affinity column extraction technique was used to purify partially a substance from human urine which was similar to the mouse hormone in both its biological activity and immunoreactivity.
Human Interferon Production: Superinduction by 5,6-Dichloro-1-β-D-Ribofuranosylbenzimidazole
Authors: Sehgal Pravinkumar B. , Tamm Igor , Vilček Jan
Published: October 2006

Polyinosinic ⋅ polycytidylic acid [poly(I⋅C)] induced production of interferon by a strain of diploid human fibroblasts (FS-4), measured between 5 and 24 hours from induction, is enhanced up to 128-fold by 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole (DRB), a reversible inhibitor of nuclear heterogeneous RNA synthesis. A normalized dose-effect plot shows a close correlation between the superinducing effect of DRB and inhibition of RNA synthesis. Cultures that contained DRB continue to produce interferon for up to 4 days. Removal of the drug at any time during this period leads to a prompt shutoff of interferon production.
"Half" Membrane Enrichment: Verification by Electron Microscopy
Authors: Fisher Knute A.
Published: October 2006

Membranes of intact erythrocytes bound to polylysine-treated glass fracture nonrandomly when covered with thin copper and frozen. Electron microscopic examination of the glass side reveals extensive areas of outer "half" membrane (B face) and of the copper side, inner "half" membrane (A face). This technique allows the ultrastructural examination of square-centimeter areas of fractured membrane and the chemical analysis of these membrane "halves".
Calcium Ion Distribution in Cytoplasm Visualized by Aequorin: Diffusion in Cytosol Restricted by Energized Sequestering
Authors: Rose Birgit , Loewenstein Werner R.
Published: October 2006

The distribution of Ca
2+
in the cytoplasm following a local rise in Ca
2+
concentration is visualized by means of aequorin luminescence and a television system with an image intensifier. Diffusion of Ca
2+
through the cytosol is so constrained that a rise in cytoplasmic Ca
2+
concentration produced by local Ca
2+
entry through cell membrane or by local Ca
2+
injection is confined to the immediate vicinity of these sites. The diffusion constraints are lifted by treatment with cyanide or ruthenium red. Thus, energized calcium sequestering, probably by mitochondria, is the dominant factor in the constraints. In cell regions where the sequestering machinery is sufficiently dense, different Ca
2+
message functions inside a cell may be effectively segregated, permitting private-line intracellular communication.
Color Receptor Identities of Goldfish Cones
Authors: Marc Robert E. , Sperling Harry G.
Published: October 2006

Goldfish retinas were exposed to spectral lights, then incubated with nitroblue tetrazolium chloride. Diformazan deposits revealed that five morphologically distinct cone types were segregated into three color classes: red long double and long single cones, green short double and long single cones, and blue short single and miniature short single cones.
Prolonged Ethanol Consumption Increases Testosterone Metabolism in the Liver
Authors: Rubin Emanuel , Lieber Charles S. , Altman Kurt , Gordon Gary G. , Southren A. Louis
Published: October 2006

Male alcoholics often suffer from features of hypogonadism related to abnormal metabolism of sex steroids. Since the activity of testosterone reductases is rate limiting for testosterone metabolism in the liver, the effect of prolonged ethanol consumption by rats and human volunteers on the activities of these microsomal and cytosolic enzymes was studied. In rats, long-term ethanol ingestion doubled microsomal 5α-testosterone reductase activity, a major pathway for testosterone metabolism, while in human volunteers the activity was increased two- to fivefold. These changes may play a role in the altered androgenic activity of the chronic alcoholic.
RETRACTED: Differing Attenuation Coefficients of Normal and Infarcted Myocardium
Authors: Adams Douglass F. , Hessel Samuel J. , Judy Philip F. , Stein Jay A. , Abrams Herbert L.
Published: October 2006

There are significant differences in attenuation coefficients between normal and infarcted myocardium measurable with a computerized transaxial tomographic scanner. Additionally, iodinated contrast material administered prior to killing the test animals resulted in excellent visualization of the blood-myocardial interface at a time when standard radiographs detected no differences between the ventricular cavity and the myocardial wall. These natural and induced changes in attenuation coefficients offer a new approach to evaluating and understanding the processes of tissue injury and death. Their clinical relevance lies in application to the twin problems of myocardial infarction and the structure and function of the cardiac wall.
Uterotrophic Effect of Delta-9-Tetrahydrocannabinol in Ovariectomized Rats
Authors: Solomon Jolane , Cocchia Mary Ann , Gray Rebecca , Shattuck Douglas , Vossmer Anne
Published: October 2006

Chronic administration of delta-9-tetrahydrocannabinol, an active component of marihuana, has significant uterotrophic effects in ovariectomized rats as measured by the uterine weight gain bioassay for estrogens.
Aflatoxin Production by a Variant of
Aspergillus oryzae
(NRRL Strain 1988) on Cowpeas (
Vigna sinensis
)
Authors: El-Hag Nabil , Morse Roy E.
Published: October 2006

Aflatoxin B
1
, B
2
, G
1
, and G
2
are produced when a variant of
Aspergillus oryzae
(NRRL strain 1988) is grown on cowpeas or rice. The present study indicates that a strain of Aspergillus oryzae approved for use in food processing is variable and the resulting variant, unlike the parent strain, has a propensity to produce aflatoxin.
Mixed Cultures of Sperm and Leukocytes as a Measure of Histocompatibility in Man
Authors: Levis William R. , Whalen John J. , Sherins Richard J.
Published: October 2006

Human peripheral blood leukocyte cultures containing varying numbers of washed fresh sperm were cultured for 4 days. [
3
H] Thymidine incorporation was used as a measure of lymphocyte transformation. Human sperm cells induce a 4- to 250-fold increase in [
3
H] thymidine incorporation in allogeneic leukocyte cultures, but no increase was demonstrated in autologous leukocyte cultures. The response was dose-dependent with maximum stimulation obtained at 2 × 10
6
sperm per milliliter of culture. Seminal plasma was inhibitory in a dose-dependent fashion and as little as 0.2 microliter per 200 microliters of culture was inhibitory. The data indicate that tissues other than leukocytes can express the portion of the major histocompatibility complex responsible for allospecific lymphocyte transformation, and thus may have application in transplantation and reproductive biology.
Partial Pressure of Ammonia in Alveolar Air
Authors: Jacquez John A. , Poppell J. William , Jeltsch Rudolph
Published: October 2006

The partial pressure of ammonia in alveolar air was measured and found to be the same (within the limits of experimental error) as the calculated partial pressure of ammonia in arterial plasma. It is likely that ammonia is equilibrated between alveolar air and the blood during its passage through the pulmonary capillaries.
Spectroscopic Evidence of Metabolic Control
Authors: Chance Britton , Hess Benno
Published: October 2006

The Pasteur and Crabtree effects demonstrate that changes at the beginning of the metabolic sequence for glucose metabolism give rise to effects at the end, and vice versa. We have presented here three additional responses of the ascites tumor cell suspensions, and presumably more will be uncovered. Each one of these responses is a manifestation of factors in the underlying mechanism that are in the nature of chemical feedback of a linear or nonlinear nature. The metabolic reactions are sufficiently complex that it is unlikely that any single component or step need control metabolism in different types of cells or under all conditions for a particular cell. However, it is due to a favorable circumstance that, in an appropriate type of cell and with the use of a direct intracellular indicator for changes in ADP concentration, we can state that the respiratory metabolism of the ascites tumor cell suspension, as freshly withdrawn from the mouse abdomen, is limited by the intracellular ADP concentration, and that this is why these cells show a predominance of glycolytic over respiratory activity. The response of the metabolism to small and large additions of glucose illustrates aspects of the metabolic mechanism which involve control of endogenous metabolism and compartmentalization of ATP formed in oxidative phosphorylation, the net result being a depression of the respiratory activity. The results of this approach emphasize the importance of chemical assays of localized portions of the living cell in its physiological state.
Measurement of Regional Blood Flow by Indicator Dilution
Authors: Levinson Gilbert E. , Cudkowicz Leon , Abelmann Walter H.
Published: October 2006

Appropriate selection of injection and collection sites permits quantification of certain regional blood flows by the single-injection, indicator-dilution method. Quantifying formulas are derived, and application of the method to several regional beds is described.
Multiple Hemoglobins in Fishes
Authors: Buhler Donald R. , Shanks Warren E.
Published: October 2006

Paper electrophoregrams of the hemoglobins from 14 species of fresh- and salt-water fish demonstrated from one to three components. The relative distribution of these fractions was determined for all species. Mobilities of the three hemoglobins of rainbow trout were calculated from moving-boundary patterns. Low anodal mobility at
p
H 8.8 was characteristic of many species examined.
Carbon Monoxide in Green Plants
Authors: Wilks Syrrel S.
Published: October 2006

Green plants grown in a closed, illuminated system liberate small quantities of carbon monoxide. Similarly, finely divided powder and chlorophyll extracts of green plants, when illuminated in an environment of oxygen and water, will yield small quantities of carbon monoxide as well as certain aldehydes. The component of the light spectrum which is absorbed in photosynthesis (480 to 680 mμ) was found to be responsible for the CO and aldehyde phenomena.
Role of Myocardial Catecholamines in Cardiac Contractility
Authors: Lee Woo Choo , Shideman F. E.
Published: October 2006

In cats bilateral sympathectomy or administration of reserpine results in a marked reduction in concentration of myocardial catecholamines. The contractility of papillary muscles from such animals is significantly less than that of muscles from untreated animals. These findings demonstrate the importance of normal levels of myocardial catecholamines in the maintenance of normal cardiac contractility.
Dissolution of Interlayers from Intergradient Soil Clays after Preheating at 400°C
Authors: Dixon J. B. , Jackson M. L.
Published: October 2006

Dehydroxylated interlayers have been removed from chlorite-vermiculite-montmorillonite intergrades by boiling the preheated sample in 0.5
N
NaOH for 2.5 minutes. Elements extracted can be conveniently analyzed spectrophotometrically. A convenient method of estimating the amount of elements present in interlayer positions and preparing the sample for analysis for expanding and nonexpanding mineral components is thus provided.
Sublimation Freeze-Drying without Vacuum
Authors: Meryman H. T.
Published: October 2006

Analysis of the freeze-drying procedure shows that the passage of water vapor from the drying boundary through the dried shell is facilitated primarily by the vapor pressure gradient rather than by the absolute pressure of the system. This is experimentally confirmed, and a device for freeze-drying at atmospheric pressure is described.
Self-Absorption Correction for Carbon-14
Authors: Hendler Richard W.
Published: October 2006

A new and simple technique has been developed for correcting C
14
radioactivity measurements for loss of radiation due to self-absorption. Results are discussed which show the applicability of the technique for many different counting situations. It is found that the absorption of radiation follows a hyperbolic law much more closely than an exponential one. Furthermore, the absorption coefficient for the sample itself has been found to be a function of weight rather than a constant, as had been assumed for the derivation of the law of exponential absorption.
Mitotic Arrest by Deuterium Oxide
Authors: Gross Paul R. , Spindel William
Published: October 2006

In marine invertebrate eggs, where cell divisions occur without growth, deuterium oxide produces arrest of, or serious delay in, mitosis and cytokinesis. All stages requiring assembly or operation of mechanical structures in the cytoplasm are sensitive to D
2
O. The block is reversible in some cells.
Characterization of Endogenous Ethanol in the Mammal
Authors: McManus I. Rosabelle , Contag Arthur O. , Olson Robert E.
Published: October 2006

Ethanol has been isolated from the tissues of several animal species in amounts ranging from 23 to 145 μmole/100 gm of tissue. Intestinal bacterial flora appear to be excluded as a source of this ethanol. Radioactivity from pyruvate-2-C
14
appeared in ethanol after incubation with liver slices; this finding indicates an endogenous synthesis.
Fatal Disease of Swine Due to Encephalomyocarditis Virus
Authors: Murnane Thomas G. , Craighead John E. , Mondragon Harold , Shelokov Alexis
Published: October 2006

Encephalomyocarditis virus was isolated from the organs of swine dying during an outbreak of an acutely fatal disease occurring on a farm in Panama. The outstanding lesion was severe myocarditis. Pigs inoculated with the viral isolate developed a systemic infection with myocarditis.
Autoradiographic Investigation of Incorporation of H
3
-Thymidine into Cells of the Rat and Mouse
Authors: Schultze Brigitte , Oehlert Wolfgang
Published: October 2006

The application of H
3
-thymidine results in labeling of those nuclei of cells in which deoxyribonucleic acid (DNA) is synthesized during the interval between application and the sacrifice of the animal. This paper reports autoradiographic investigation with H
3
-thymidine of rats and mice. This method permits a more exact statement of the number of dividing cells than does the microscopic estimate of mitosis. The latter method is practically impossible in tissues with small fusiform cells. Moreover, it is possible to obtain information about the relative time of DNA synthesis in different cells.
Finite Radiocarbon Dates of the Port Talbot Interstadial Deposits in Southern Ontario
Authors: de Vries Hessel , Dreimanis Aleksis
Published: October 2006

Three new finite radiocarbon dates suggest that (i) the thermal maximum of the Port Talbot interstadial occurred prior to 47,000 years before the present and (ii) the interstadial deposits were overridden by a glacial advance approximately 44,000 years before the present. To facilitate correlations with other areas, new rock-stratigraphic names are proposed for the Port Talbot type section.
Requirements for Phosphorylation of Map Kinase During Meiosis in
Xenopus
Oocytes
Authors: Posada James , Cooper Jonathan A.
Published: October 2006

Mitogen-activated protein (MAP) kinases are activated in response to a variety of extracellular stimuli by phosphorylation on tyrosine and threonine residues. Xp42 is a
Xenopus laevis
MAP kinase that is activated during oocyte maturation. Modified forms of Xp42 that lacked enzymatic activity or either of the phosphorylation sites were expressed in
Xenopus
oocytes. When meiotic maturation was induced with progesterone, each mutant Xp42 was phosphorylated, indicating that at least one kinase was activated that can phosphorylate Xp42 on tyrosine and threonine. Phosphorylation of one residue is not strictly dependent on phosphorylation of the other.
Competitive Exclusion
Authors: Cole Lamont C.
Published: October 2006

It is contended that there is little justification and no necessity for believing in the competitive exclusion principle as usually formulated. There is danger that a trite maxim like this may lead to the neglect of important evidence.
Transmissible Agent Associated with 26 Types of Experimental Mouse Neoplasms
Authors: Riley Vernon , Lilly Frank , Huerto Editha , Bardell David
Published: October 2006

A transmissible agent or factor has been found to be associated with all transplanted and spontaneous experimental tumors examined. This observation was made possible by utilization of a biochemical response of normal animals when inoculated with plasma or organ extracts from tumor-bearing hosts. This transmissible enzymic "lesion" is expressed by a five- to tenfold increase in the plasma lactic dehydrogenase activity of the injected normal test animals. The factor is heat labile, passes through bacteria-retaining filters, but is nondialyzable. It is partially sedimented by centrifugation at 100,000g for 1 hour.
Action Potential and Contraction of
Dionaea muscipula
(Venus Flytrap)
Authors: Di Palma Joseph R. , Mohl Robert , Best William
Published: October 2006

Observation of the action potential and contraction of the leaf of
Dionaea muscipula
Ellis revealed several interesting phenomena. Two successive stimuli are generally necessary to cause contraction. The first and ineffective stimulus is associated with slow depolarization. The second stimulus has much more rapid depolarization and initiates contraction.
Sounds Emitted by the Bottlenose Dolphin
Authors: Lilly John C. , Miller Alice M.
Published: October 2006

The sonic emissions of the bottlenose dolphin are remarkably complex. Three classes of these sounds are discussed and presented graphically. The sine-type wave whistles range in frequency from about 4000 to 18,000 cycles per second. The clicks contain components of this same frequency range plus some components of higher frequencies. Complex waves of high amplitude and of many frequencies are also emitted in water or in air. Situations in which sounds of one or more of these classes can be elicited simultaneously from one and from two restrained animals are described. The necessity for, and occurrence of, creakings for purpose of navigation, ranging, and recognition (sonar) have been eliminated in the experiments under discussion.
Preference Factors in Experimental Alcoholism
Authors: Myers Robert D. , Carey Robert
Published: October 2006

Normal rats which refused 5- and 20-percent alcohol in a previous study were restricted to 5-percent and 20-percent solutions in their home cages for either 30 or 120 days. Differential preferences for alcohol solutions of up to 8-percent were established as a function of length of time animals consumed alcohol but not as a function of the particular concentration consumed prior to testing.
Gonadotrophic Hormones Affect Aggressive Behavior in Starlings
Authors: Mathewson Sue F.
Published: October 2006

Injections of gonadotrophic hormones into subordinate male European starlings produced reversals in social rank, suggesting that pituitary gonadotrophic hormones rather than gonadal hormones influence aggressive behavior in this species.
Neural Activity in the Parietal Eye of a Lizard
Authors: Miller William H. , Wolbarsht Myron L.
Published: October 2006

Electrical signs of activity in response to illumination of the parietal eye of the American chameleon,
Anolis carolinensis,
have been investigated. The responses were of two types. Under conditions of direct-coupled amplification, with glass pipette electrodes recording extracellularly from the retinal surface, the response consisted of an increase in negativity maintained throughout prolonged illumination. With capacitance-coupled amplification and metal electrodes, brisk mass discharges of nerve impulses were detected at the onset and cessation of illumination. During illumination a less vigorous maintained discharge was observed.
The Hasanlu Project
Authors: Dyson Robert H.
Published: October 2006

The aim of this article has been to indicate some of the work in progress, both in the field and in the laboratory, in connection with the Hasanlu project. Since this work is still going on, no definitive conclusions can be reached in regard to the many special studies which our raw data have made possible.
Retention as a Function of Degree of Overlearning
Authors: Postman Leo
Published: October 2006

The effects of overlearning on retention were investigated with serial lists of words of high and low frequency of linguistic usage. For both types of materials, amount recalled showed a positively accelerated increase with degree of overlearning. These increases in recall resulted from improved retention of relatively difficult parts of the lists. Speed of relearning to complete mastery was a direct function of degree of overlearning.
Myo-inositol in the Biosynthesis of Streptomycin by
Streptomyces griseus
Authors: Majumdar S. K. , Kutzner H. J.
Published: October 2006

When myo-inositol is present in a growing culture of
Streptomyces griseus
the yield of streptomycin is increased, and the amount of carbon-14—from uniformly labeled glucose—incorporated into the streptidine and streptobiosamine moieties of streptomycin is lowered by 41 percent and 21.7 percent, respectively. These results present strong indirect evidence for the participation of myo-inositol or its metabolic products in streptidine biosynthesis.
Eliminative Split of Pectic Substances by Phytopathogenic Soft-Rot Bacteria
Authors: Starr Mortimer P. , Moran Francis
Published: October 2006

Culture filtrates of
Erwinia carotovora
and
Bacillus polymyxa
split pectic substances to yield a product that absorbs at 230 mμ, and which reacts with thiobarbituric acid to form a substance that absorbs at 547 mμ. This product is believed to be a C-4,5-unsaturated oligouronide. The preferred substrate is polygalacturonic acid rather than pectin; the enzyme, provisionally named polygalacturonic-
trans
-eliminase, is activated by calcium.
Drive Decay: The Cause of Fast "Extinction" of Habits Learned for Brain Stimulation
Authors: Howarth C. I. , Deutsch J. A.
Published: October 2006

According to Deutsch's theory of intracranial self-stimulation, cessation of responding after the withdrawal of the stimulus should be a simple function of time without stimulation. To test this prediction, the lever was withdrawn from a Skinner box for varying times, then replaced and normal extinction completed. The number of extinction trials was a simple function of the time the lever was out of the box, thus confirming Deutsch's hypothesis that cessation of responding in this instance is due to a decay of a motivational excitation produced by the electrical stimulation, and not a function of the number of unreinforced trials as in normal extinction.
Reinforcing Brain Stimulation in Competition with Water Reward and Shock Avoidance
Authors: Valenstein Elliot S. , Beer Bernard
Published: October 2006

Employing response rate as the index of reinforcing strength in self-stimulation experiments is questioned. With water reward or shock avoidance placed in competition with brain stimulation, self-stimulation rate does not reflect relative reinforcement value. The results agree with preference tests which show that, for a given electrode site, stimulus intensity, not rate, is directly related to reward strength.
Nitric Oxide: A Physiologic Mediator of Penile Erection
Authors: Burnett Arthur L. , Lowenstein Charles J. , Bredt David S. , Chang Thomas S. K. , Snyder Solomon H.
Published: October 2006

Nitric oxide (NO) is a cytotoxic agent of macrophages, a messenger molecule of neurons, and a vasodilator produced by endothelial cells. NO synthase, the synthetic enzyme for NO, was localized to rat penile neurons innervating the corpora cavernosa and to neuronal plexuses in the adventitial layer of penile arteries. Small doses of NO synthase inhibitors abolished electrophysiologically induced penile erections. These results establish NO as a physiologic mediator of erectile function.
Relation of Infrared Spectra to Coordination in Quartz and Two High-Pressure Polymorphs of SiO
2
Authors: Sclar C. B. , Carrison L. C. , Schwartz C. M.
Published: October 2006

Infrared spectra of the four-coordinated quartz and coesite polymorphs of SiO
2
, the rutile six-coordinated (stishovite) polymorph of SiO
2
, and the quartz and rutile polymorphs of GeO
2
show that a change from tetrahedral to octahedral cation coordination results in (i) a 23-percent increase in the wavelength of the main absorption band for both the SiO
2
and GeO
2
polymorphs and (ii) a significant increase in the force constant of the same magnitude for the SiO
2
and GeO
2
polymorphs. The quartz and the rutile isostructural pairs for SiO
2
and GeO
2
show that the effect of increasing mass is to increase proportionally the wavelength of the respective main absorption bands. The infrared data for the rutile form of SiO
2
fit the empirical equation of Dachille and Roy relating cation coordination, mass, atomic number, valence, and main absorption wavelength.
Anthrax Toxin: Causative Agent in the Death of Rhesus Monkeys
Authors: Klein Frederick , Hodges Dean R. , Mahlandt Bill G. , Jones William I. , Haines Bertram W. , Lincoln Ralph E.
Published: October 2006

Anthrax toxin was present in the blood obtained from rhesus monkeys at the terminal stage of anthrax and was also present in increasing amounts in the lymph as death approached. When sterile toxin produced in vitro was injected in sufficient amounts, monkeys died unless they were injected with specific antiserum. Death with symptoms of toxemia occurred within 2 hours after injection of 10
11
spores, whereas 10
10
spores or less required 20 or more hours of growth in vivo to cause death.
Removal of Potassium Alters
b
-Dimension of Muscovite
Authors: Burns Allan F. , White Joe L.
Published: October 2006

By treatment of muscovite with molten lithium nitrate at 300°C we have been able to remove a large portion of the interlayer potassium and observe a decrease in the apparent
b
-axis length as a function of potassium content over the range of 8.8 to 0.7 percent potassium. The
b
-axis length of Silversheen mica (a 2M
1
muscovite) decreases from 9.024 to 8.988 Å as the potassium content decreases from 8.79 to 3.31 percent. The contraction of the
b
-dimension results in an effective decrease in the size of the ditrigonal opening in the planar surfaces with a consequent increase in the d
001
upon re-saturation with potassium.
Ytterbium: Transition at High Pressure from Face-Centered Cubic to Body-Centered Cubic Structure
Authors: Hall H. Tracy , Barnett J. Dean , Merrill Leo
Published: October 2006

Pressure of 40,000 atmospheres at 25°C induces a phase transformation in ytterbium metal; the face-centered cubic structure changes to body-centered cubic. The radius of the atom changes from 1.82 to 1.75 Å. At the same time the atom's volume decreases by 11 percent and the volume, observed macroscopically, decreases 3.2 percent.
Divergent Reactions to the Threat of War
Authors: Ekman Paul , Cohen Lester , Moos Rudolf , Raine Walter , Schlesinger Mary , Stone George
Published: October 2006

While the extent of similarity between the two groups was surprising, this similarity may have been due to the particular community studied and should not obscure the real differences which were found, which apparently remained fairly stable. The two groups differed not only in their beliefs about shelters but in their attitudes toward war, United States foreign policy, the motives of the Soviet Union, political affiliation and activity, risk-taking behavior, their own descriptions of themselves and of the opposite group, and a number of general social issues. Finally, each group had misperceptions about the other, one group exaggerating, the other under-rating, the differences.
Lactate Dehydrogenases in Human Testes
Authors: Blanco Antonio , Zinkham William H.
Published: October 2006

A unique form of lactate dehydrogenase was observed in the starch-gel electrophoretic patterns of adult human testes. It was present in sperm, but absent in prepubertal testes. Its electrophoretic mobility, heat stability, kinetic behavior with pyridine nucleotide analogs, and chromatographic characteristics on diethylaminoethyl cellulose were intermediate to those observed for lactate dehydrogenase isozymes 3 and 4.
Botulinus Toxin: Effect on the Central Nervous System of Man
Authors: Tyler H. Richard
Published: October 2006

Electrical stimulation of multiple peripheral nerves, elicited "H" reflexes in a patient, 61 years old, with botulism. These reflexes are extremely suggestive of some central release or failure of inhibitory control of a monosynaptic or polysynaptic spinal reflex arc. This "central" action of botulinus toxin is similar to that suggested for tetanus toxin.
Xenon Tetrafluoride Molecule and Its Thermal Motion: A Neutron Diffraction Study
Authors: Burns John H. , Agron P. A. , Levy Henri A.
Published: October 2006

A neutron-diffraction analysis of the xenon tetrafluoride crystal structure has confirmed the square-planar symmetry of the molecule; from the data the average Xe to F bond length is 1.953 Å (σ = .002) and the F to Xe to F angle is 90.0° (σ = 0.1). A description of the thermal displacements in the crystal is given.
Geologic Evolution of North America
Authors: Engel A. E. J.
Published: October 2006

The oldest decipherable rock complexes within continents (more than 2.5 billion years old) are largely basaltic volcanics and graywacke. Recent and modern analogs are the island arcs formed along and adjacent to the unstable interface of continental and oceanic crusts. The major interfacial reactions (orogenies) incorporate pre-existing sial, oceanic crust, and mantle into crust of a more continental type. Incipient stages of continental evolution, more than 3 billion years ago, remain obscure. They may involve either a cataclysmic granite-forming event or a succession of volcanic-sedimentary and granite-forming cycles. Intermediate and recent stages of continental evolution, as indicated by data for North America, involve accretion of numerous crustal interfaces with fragments of adjacent continental crust and their partial melting, reinjection, elevation, unroofing, and stabilization. Areas of relict provinces defined by ages of granites suggest that continental growth is approximately linear. But the advanced differentiation found in many provinces and the known overlaps permit wide deviation from linearity in the direction of a more explosive early or intermediate growth.
Methotrexate: Suppression of Experimental Allergic Encephalomyelitis
Authors: Brandriss Michael W.
Published: October 2006

Methotrexate inhibited the production of allergic encephalomyelitis in guinea pigs when administered between the time of sensitization and the onset of disease. If treatment was delayed until the day of onset of encephalomyelitis, the disease was still suppressed and the death rate was reduced. The protective effect of methotrexate was reversed by folinic acid.
Prolonged Immobilization of the Body: Changes in Performance and in the Electroencephalogram
Authors: Zubek John P. , Wilgosh L.
Published: October 2006

Subjects who were immobilized for a week but otherwise were exposed to a normal and varied sensory environment showed intellectual and perceptual deficits similar in many respects to those occurring after prolonged visual and auditory deprivation. A significant change in the electroencephalogram was also observed.
Siphonophores and the Deep Scattering Layer
Authors: Barham Eric G.
Published: October 2006

Bathyscaphe dives in the San Diego Trough have revealed a close spatial relation between siphonophores and the deep scattering layer as recorded by precision depth recording echo-sounders. Measurements of gas bubbles within the flotation structures of
Nanomia bijuga
captured in a closing net in an ascended scattering layer indicate that these are very close to the resonant size for 12-kcy/sec sound. Because such organisms are capable of making prolonged vertical migrations, and are widespread geographically, they are very probably the major cause of stratified zones of scattering throughout the oceans of the world.
Equilibrium Sedimentation of Uniform Rods of Tobacco Mosaic Virus
Authors: Weber F. N. , Elton R. M. , Kim H. G. , Rose R. D. , Steere R. L. , Kupke D. W.
Published: October 2006

Equilibrium was achieved in centrifugal fields with tobacco mosaic virus by the Beams magnetically suspended ultracentrifuge. An attempt was made to account for the earth's gravitational component by using tilted cells in the rotor. The determinations of particle weight on highly uniform rods of tobacco mosaic virus in the apparent absence of nonideal behavior gave a value of (41.6 ± 0.1) 10
6
.
Geothermal Heat Flow in the Gulfs of California and Aden
Authors: Von Herzen Richard P.
Published: October 2006

Eighteen measurements in and near the gulfs of California and Aden indicate the geothermal flux is several times the world-wide mean of 1.2 × 10
-6
cal/cm
2
sec in both regions. Both gulfs closely coincide with the intersection of oceanic rises with continents and have likely been formed under tensional forces, which suggests an association with mantle convection currents.
Lymphocyte-Defined Loci in Cattle
Authors: Usinger William R. , Curie-Cohen Martin , Stone W. H.
Published: October 2006

Using the results of all paired one-way mixed lymphocyte culture tests on families of half-sibs, we have established that the lymphocyte-defined system in cattle contains a minimum of two loci. The methodology presented is applicable to studies of the lymphocyte-defined systems of other species.
Uranyl Ion Coordination
Authors: Evans Howard T.
Published: October 2006

A review of the known crystal structures containing the uranyl ion shows that plane-pentagon coordination is equally as prevalent as plane0square or plane-hexagon. It is suggested that puckered-hexagon configurations of OH
-
or H
2
O about the uranyl group will tend to revert to plane-pentagon coordination. The concept of pentagonal coordination is invoked for possible explanations of the complex crystallography of the natural uranyl hydroxides and the unusual behavior of polynuclear ions in hydrolyzed uranyl solutions.
Sucrose: Precise Determination of Crystal and Molecular Structure by Neutron Diffraction
Authors: Brown George M. , Levy Henri A.
Published: October 2006

This analysis provides the first precise molecular parameters for sucrose. All hydrogen atoms are included. Carbon-carbon distances are 1.51 to 1.53 Å; carbon-oxygen 1.40 to 1.44 Å; carbon-hydrogen 1.08 to 1.11 Å; oxygen-hydrogen 0.94 to 0.99 Å. The furanose ring conformation differs from that in sucrose sodium bromide dihydrate. Hydrogen bonds (two of them intramolecular) utilize every hydroxyl group except one.
Isolation of the Monkey Brain: In vitro Preparation and Maintenance
Authors: White Robert J. , Albin Maurice S. , Verdura Javier
Published: October 2006

Sustained viability of the primate brain, as a totally isolated organ preparation, was achieved by utilizing an extracorporeal (compatible donor) circulation. Five rhesus monkey brains, completely isolated neurogenically and vascularly, were perfused in vitro for 30 to 180 minutes. Retention of biological activity was evidenced by: (i) persistent electrocortical activity, and (ii) significant mean A-V

O
2

(5.8 volumes percent) and V-A

CO
2

(5.0 volumes percent) differences across the isolated brain.
Demography of Genotypes: Failure of the Limited Life-Span Paradigm inDrosophila melanogaster
Authors: Curtsinger James W. , Fukui Hidenori H. , Townsend David R. , Vaupel James W.
Published: October 2006

Experimental systems that are amenable to genetic manipulation can be used to address fundamental questions about genetic and nongenetic determinants of longevity. Analysis of large cohorts of ten genotypes ofDrosophila melanogasterraised under conditions that favored extended survival has revealed variation between genotypes in both the slope and location of age-specific mortality curves. More detailed examination of a single genotype showed that the mortality trajectory was best fit by a two-stage Gompertz model, with no age-specific increase in mortality rates beyond 30 days after emergence. These results are contrary to the limited life-span paradigm, which postulates well-defined, genotype-specific limits on life-span and brief periods of intense and rapidly accelerating mortality rates at the oldest age.
Ornithocholanic Acids and Cholelithiasis in Man
Authors: Peric-Golia Ludvik , Jones Russell S.
Published: October 2006

Ornithocholanic acids and small soft gall stones were found in the bile of patients from which
Klebsiella pneumoniae
was also isolated. Cholelithiasis may be initiated by metabolic disturbances in the conjugation of bile acids in liver tissue and the subsequent precipitation of cholesterol and bile pigment.
Norepinephrine and 3,4-Dihydroxy-Phenethylamine Turnover in Guinea Pig Brain in vivo
Authors: Udenfriend S. , Zaltzman-Nirenberg P.
Published: October 2006

By administering C
14
-labeled tyrosine or H
3
-labeled 3,4-dihydroxyphenylalanine to guinea pigs it has been possible to achieve sufficient labeling of the norepinephrine and dopamine in the brain to permit measurement of their turnover rates. The half-life of brain dopamine was about 2.5 hours. The half-life of norepinephrine was about 4 hours, suggesting a rate of synthesis of at least 0.03 to 0.04 μg/g per hr or 2.4 μg/day for the whole guinea pig brain.
Gamma-Globulins: Quantitative Relationships in Human Serum and Nonvascular Fluids
Authors: Chodirker W. B. , Tomasi T. B.
Published: October 2006

Three types of γ-globulins, γ
2
, γ
1A
, and γ
1M
, are present in certain body fluids and secretions in proportions significantly different from those of normal human serum. Although γ
1A
-globulin is present in only small amounts in serum, it represents a major fraction of the gamma globulin of tears, bile, saliva, colostrum, and fluid of the small intestine.
Zoospores in
Scenedesmus obliquus
Authors: Trainor Francis R.
Published: October 2006

In basal medium without a nitrogen source a 3-day-old culture of
Scenedesmus obliquus
produced zoospores, which were biflagellated, had a parietal chloroplast, lacked a pyrenoid, and were apparently not walled. Identical results were produced with new clones. A reconsideration of the relationships and classification of this organism is now essential.
Electromechanical Coupling in Potentiation of Muscular Contraction
Authors: Sandow Alexander , Taylor Stuart R. , Isaacson Allen , Seguin J. J.
Published: October 2006

Diverse potentiators of contraction have basically identical, activestate mechanical effects, but act by different membrane-mediated electromechanical coupling mechanisms. The falling phase of the action potential is greatly prolonged by Zn
2+
(0.1 m
M
) and UO
2
2+
(0.5 to 1 μ
M
), neither of which affects the mechanical threshold. Caffeine (1 m
M
), like the lyotropic anions, acts conversely. Thus changes in the duration and mechanical threshold of the action potential determine independent electromechanical coupling processes which can act individually, or conjointly in the action of other potentiators, in determining the duration of the active state and thus the potentiation of twitch tension.
Airborne Algae: Their Abundance and Heterogeneity
Authors: Brown R. Malcolm , Larson Donald A. , Bold Harold C.
Published: October 2006

The literature on the occurrence of airborne algae is reviewed briefly. Airborne algae were isolated into culture in both quantity and diversity. Qualitative experiments and culture techniques are discussed, as are quantitative sampling techniques and preliminary correlations of the occurrence of algae, fungi, and pollen in the air. The data disclose an important pathway for the dispersion of soil algae and support an observation that algae may be important as causal agents in inhalant allergies.
Condensation Model Producing Crystalline or Amorphous Tetrahedral Networks
Authors: Ordway Fred
Published: October 2006

Wire models of tetrahedral networks have been built up by a process representing condensation from a fluid, which yields amorphous structures unless a nucleus of crystalline structure is present initially. A random tetrahedral network of 300 units has been constructed for direct measurement of coordinates; the construction process is uniquely defined so that it may be possible to synthesize larger networks by use of a computer.
Glycogen Synthetase: Its Response to Cortisol
Authors: Sie Hsien-Gieh , Fishman William H.
Published: October 2006

Glycogen synthetase activity in the livers of starved mice is stimulated by the glucocorticoid, cortisol.
Radioactive Myoinositol: Incorporation into Streptomycin
Authors: Heding Henrik
Published: October 2006

Radioactive myoinositol was rapidly incorporated into streptomycin by
Streptomyces griseus
. All the incorporated radioactivity was found in the streptidine moiety of the antibiotic, as shown by chemical degradation of the streptomycin. To a certain extent inositol reversed the depressing effect of phosphate on the production of the antibiotic.
Simultaneous Studies of Firing Patterns in Several Neurons
Authors: Gerstein G. L. , Clark W. A.
Published: October 2006

A tungsten microelectrode with several small holes burnt in the vinyl insulation enables the action potentials from several adjacent neurons to be observed simultaneously. A digital computer is used to separate the contributions of each neuron by examining and classifying the waveforms of the action potentials. These methods allow studies to be made of interactions between neurons that lie close together.
Giant Polytene Chromosomes in Hypodermal Cells of Developing Footpads of Dipteran Pupae
Authors: Whitten Joan M.
Published: October 2006

Large hypodermal cells with giant polytene chromosomes are present within the developing feet of Sarcophaga and other fly pupae. The cells secrete a large volume of cuticle; at this time there is extensive "puffing" of the chromosomes. Being hypodermal and superficially situated with permanent secretory products, the cells could be ideal experimental and genetical tools.