bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of the Pyrrole Porphobilinogen by Sepharose-Linked δ-Aminolevulinic Acid Dehydratase
Authors: Gurne Daniela , Shemin David
Published: October 2006

δ-Aminolevulinic acid dehydratase from
Rhodopseudomonas spheroides
was covalently linked to Sepharose 4B, which had been activated with cyanogen bromide. A column containing this enzyme gel readily catalyzed the synthesis of the pyrrole porphobilinogen on continuous passage of a solution of δ-aminolevulinic acid. Under the conditions of the procedures, product inhibition was minimized and a 50 to 94 percent yield was attained. A column containing about 1 milligram of enzyme was continuously operated for 27 days. Although its total activity appeared to be reduced about 30 percent at the end of this time, the bound enzyme produced approximately 200 milligrams of porphobilinogen each day, and about 5 grams of the pyrrole were isolated.
Silurian Echiuroids: Possible Feeding Traces in the Thorold Sandstone
Authors: Risk M. J.
Published: October 2006

Problematic trace fossils collected from the Middle Silurian Thorold Sandstone bear a striking resemblance to feeding traces made by the proboscises of modern echiuroid worms. Paleoecological approximations of depth and salinity may be possible depending on population densities. Echiuroids may have been a significant element of the Paleozoic benthos.
Dynamics of Number Fluctuations: Motile Microorganisms
Authors: Schaefer Dale W.
Published: October 2006

The time dependence of the intensity of light scattered from motile
Escherichia coli
bacteria is studied in population densities so low that the intensity autocorrelation function reflects fluctuations in the total number of particles in the scattering region. Measured correlation functions are analyzed by using a random walk model of bacterial motion.
Health Care Delivery and Advanced Technology
Authors: Scott Charles D.
Published: October 2006

Remedying the deficiencies in the current health care delivery system and effectively using advances in biomedical research require that a significant effort be organized to develop advanced technology in this field. The time is ripe and development personnel are available; hence, what are needed are simply a dedication to solving the problem, a commitment of resources toward this end, and an organizational mode that will allow the effective participation of developmental personnel.
Late Cretaceous (Maestrichtian?) Silicoflagellates from the Alpha Cordillera of the Arctic Ocean
Authors: Ling Hsin Yi , McPherson Linda M. , Clark David L.
Published: October 2006

A Late Cretaceous (probably Maestrichtian) silicoflagellate assemblage has been recovered for the first time from the middle section of a core taken from the Alpha Cordillera in the central Arctic Ocean. The finding of
Globigerina pachyderma
in the top and very rarely in the bottom part of the core suggests a faulting or slumping process in the area.
Wood-Boring Bivalves, Opportunistic Species in the Deep Sea
Authors: Turner Ruth D.
Published: October 2006

Wood exposed for 104 days at a depth of 1830 meters at the permanent station of the research submersible D.S.R.V. Alvin was completely riddled by two species of bivalve wood borers (subfamily Xylophagainae, family Pholadidae). Their high reproductive rate, high population density, rapid growth, early maturity, and utilization of a transient habitat classify them as opportunistic species, the first recorded from the deep sea.
Xylophaga
is shown to be the most important species involved in decomposing woody plant material in the deep sea.
Cartilage Collagen: A Staggered Substructure in Reconstituted Fibrils
Authors: Bruns Romaine R. , Trelstad Robert L. , Gross Jerome
Published: October 2006

In contrast to the typical transverse banding pattern of native and reconstituted skin collagen fibrils, reconstituted fibrils of cartilage collagen have an oblique banding pattern that results from a regular axial shift (89 angstroms) of component "subfibrils." The 89-angstrom shift may be related to the major helix of the collagen molecule.
Energy Expenditure in Animal Locomotion
Authors: Gold Albert
Published: October 2006

A wide variety of data on the energy expended by animals in running, flying, or swimming can be accounted for by the simple hypothesis that all animals require the same quantity of energy to carry a unit of their own body mass one "step." For running locomotion this is approximately 3 × 10
-4
calorie per gram per step.
Stereoscopic Vision: Cortical Limitations and a Disparity Scaling Effect
Authors: Tyler C. William
Published: October 2006

The spatial limitations of stereoscopic vision were studied by using vertical line stimuli containing sinusoidal disparity variations such that different parts of the line appeared at different depths. Stimuli with a finer grain than about 3 cycles per degree did not elicit depth perception, even though the sinusoidal curvature was clearly visible monocularly. At low spatial frequencies of curvature, stereoacuity was limited to the same extent as the monocular sensitivity. The limiting disparity for Panum's fusional region and the upper depth limit are subject to a scaling effect in proportion to stimulus dimensions. The disparity scaling can be characterized by a fixed maximum angular difference between the parts of the stereoscopic half-images.
Isozymic Heterogeneity in
Tetrahymena
Strains
Authors: Borden D. , Whitt G. S. , Nanney D. L.
Published: October 2006

Examination of electrophoretic mobility patterns indicates that the strain designations of 44 classical strains of
Tetrahymena
are confused. It is suggested that new designations be made on the basis of phenotypic similarity.
Thermoperiodic Control of Diapause in an Insect: Theory of Internal Coincidence
Authors: Saunders D. S.
Published: October 2006

Females of the parasitic wasp
Nasonia vitripennis
raised from the egg stage in the total absence of light but subjected to daily temperature cycles (13° to 23°C), are able to distinguish a "short-day" thermoperiod (< 13 hours at 23°C per day) from a "long-day" thermoperiod (> 13 hours at 23°C per day) and produce diapausing or developing progeny accordingly.
Welfare Reform 1973: The Social Services Dimension
Authors: Morris Robert
Published: October 2006

The model outlined above is an advance over other proposals in the following respects.

1) The objectives of the public social services are related to the realities of at-risk target populations, but in a moderate and attainable fashion, borrowing from the approach already advanced by HEW.

2) It has proposed a composite target population, which permits the dimensions of the public social service program to be outlined and then reorganized by central function, rather than by coordination among conceptually unrelated units.

3) The laundry listing of service programs has been regrouped into a limited number of service functions, each of which has a relatively well-defined function and permits measurement.

4) The aims, service typologies, and populations at risk have all been developed in some coherent and consistent relationship with each other so that progress in the development of a service and the achievement of the aims in relation to manageable populations can be achieved over time.

5) These steps are consistent with preliminary actions already taken by HEW and by some state superagencies.

This interrelationship among aims, service conception, and populations at risk seems to be an essential characteristic of any welfare reform if the public social services are to have a capacity for synergism—that is, a capacity to use experience, to develop greater overall power for the achievement of desired ends than is now attainable by individual, unconnected segments. This pattern of interrelationships permits a testing of various service components in relation to populations and in relation to objectives, with an ultimate substitution of more successful approaches over time, and with the consequent emergence of a science of human services.
Platinum-Like Behavior of Tungsten Carbide in Surface Catalysis
Authors: Levy R. B. , Boudart M.
Published: October 2006

Tungsten carbide catalyzes the formation of water from hydrogen and oxygen at room temperature, the reduction of tungsten trioxide by hydrogen in the presence of water, and the isomerization of 2,2-dimethylpropane to 2-methylbutane. This catalytic behavior, which is typical of platinum, is not exhibited at all by tungsten. The surface electronic properties of the latter are therefore modified by carbon in such a way that they resemble those of platinum.
Hurricane Prediction and Control: Impact of Large Computers
Authors: Hammond Allen L.
Published: October 2006

This is the third is a continuing series of articles on natural disasters, their prediction and modification, and progress in understanding the physical bases of these phenomena. Two earlier articles (
Science
, 25 May, p. 851, and 1 June, p. 940) reported advances in earthquake prediction. Hurricanes are the subject here. Generally less devastating than major earthquakes—although a single hurricane in 1970 killed an estimated 200,000 persons in Bangladesh—these storms are still the most destructive of all atmospheric phenomena. A recent report of the National Academy of Sciences (see box) recommends that efforts to modify hurricanes and other severe storms become a national goal.
Perfluorocarbons Having a Short Dwell Time in the Liver
Authors: Clark Leland C. , Becattini Fernando , Kaplan Samuel , Obrock Virginia , Cohen David , Becker Charles
Published: October 2006

Perfluorinated organic liquids are useful as high capacity oxygen and carbon dioxide solvents. After intravenous infusion most of these perfluorinated emulsions are deposited in the liver and spleen in a matter of days, where they remain for the lifetime of the animal. Hence, while they may be useful as isolated organ perfusion media their value as artificial blood is limited. A family of perfluorocarbons has now been discovered, which, although deposited in the liver after circulation in the blood, leave the liver to be excreted via the lungs and skin in a matter of days without apparent harm to the animal.
Prostaglandin Involvement in Hypothalamic Control of Gonadotropin and Prolactin Release
Authors: Harms P. G. , Ojeda S. R. , McCann S. M.
Published: October 2006

Prostaglandin E
2
(PGE
2
) injected into the third ventricle of ovariectomized rats increased plasma luteinizing hormone dramatically and follicle stimulating hormone slightly. PGE
1
elevated prolactin; PGF
1α
or PGF
2α
had no effect. PGE
2
or PGE
1
injected directly into the anterior pituitary were ineffective. These results suggest that specific prostaglandins act at the hypothalamus to control pituitary hormone release.
Toxic Metal Fumes from Mantle-Type Camp Lanterns
Authors: Griggs Kyle
Published: October 2006

The mantle of a gas lantern contains about 600 micrograms of toxic beryllium metal. Most of the beryllium is volatilized and becomes airborne during the first 15 minutes of use of a new mantle. The inhalation of this quantity of beryllium can be hazardous.
Human Chorionic Gonadotropin: Its Possible Role in Maternal Lymphocyte Suppression
Authors: Adcock Eugene W. , Teasdale François , August Charles S. , Cox Sheila , Meschia Giacomo , Battaglia Frederick C. , Naughton Michael A.
Published: October 2006

Human chorionic gonadotropin completely inhibits the response of lymphocytes to phytohemagglutinin. The effect is both reversible and noncytotoxic. These observations support the theory that the fetus is accepted because human chorionic gonadotropin represents trophoblastic surface antigen and blocks the action of maternal lymphocytes.
Diisopropylfluorophosphate: Suppression of Ionic Conductance of the Cholinergic Receptor
Authors: Kuba K. , Albuquerque E. X. , Barnard E. A.
Published: October 2006

When frog sartorius muscles were exposed to diisopropylfluorophosphate, the amplitude and half-decay time of the end-plate current decreased; the half-decay time became almost potential-independent and the equilibrium potential for the end-plate current was more negative than during control conditions. When the excess reagent was removed by washing so that only the phosphorylated acetylcholinesterase remained, the amplitude of the end-plate current was restored, while its half-decay time was markedly increased. These findings reveal that this organophosphate significantly affects the receptor-ionic conductance modulator complex in addition to its well-known anticholinesterase activity.
Insomnia with Sleep Apnea: A New Syndrome
Authors: Guilleminault Christian , Eldridge Frederic L. , Dement William C.
Published: October 2006

A new clinical syndrome, sleep apnea associated with insomnia, has been characterized. Repeated episodes of apnea occur during sleep. Onset of respiration is associated with general arousal and often complete awakening, with a resultant loss of sleep. An important clinical implication is that patients complaining only of insomnia may be suffering from this syndrome.
Disparity Detectors in Human Depth Perception: Evidence for Directional Selectivity
Authors: Regan D. , Beverley K. I.
Published: October 2006

Viewing a target moving in depth depresses visual sensitivity to depth when test and adapting stimuli simulate motion along closed paths with the same directions of rotation. However, for opposite directions of rotation, sensitivity is either unaffected or increased. This points to two classes of disparity detectors. Either eye's input to a single class of disparity detector consists of the physiological responses to a single direction of horizontal movement.
Regulation of Phosphodiesterase Synthesis: Requirement for Cyclic Adenosine Monophosphate-Dependent Protein Kinase
Authors: Bourne Henry R. , Tomkins G. M. , Dion Sally
Published: October 2006

Endogenous cyclic adenosine monophosphate (AMP) and its dibutyryl derivative increase cyclic AMP phosphodiesterase activity in cultured lymphoma cells. This effect is prevented by cycloheximide. A variant population of cells deficient in cyclic AMP-dependent protein kinase contains lower basal phosphodiesterase activity, which cannot be induced by cyclic AMP.
Thirst Satiation and the Temperature of Ingested Water
Authors: Deaux Edward
Published: October 2006

Ingestion in rats given limited daily access to water of 12°, 24°, and 37°C is a positive function of water temperature, even though ingestion of warm water decreases blood osmotic concentration faster than cold water. The paradox suggests that temperature-dependent gastric factors and water-transport factors determine stomach distention cues of thirst satiation.
Subfornical Organ: Site of Drinking Elicitation by Angiotensin II
Authors: Simpson John B. , Routtenberg Aryeh
Published: October 2006

Angiotensin II applied directly to the subfornical organ in a dose as small as 0.1 nanogram elicited short-latency drinking behavior in water-sated rats. Lesions in the body of this structure blocked drinking induced by angiotensin II applied to the basal telencephalon (including preoptic area). These results call attention to the subfornical organ as an important central nervous structure involved in the control of drinking behavior.
Spontaneous Whole Brain Slow Potential Changes during Recovery from Experimental Neurosurgery
Authors: Irwin Don A. , Criswell Hugh E. , Kakolewski Jan W.
Published: October 2006

Prolonged, nonlocalized brain slow potential changes, frequently associated with cortical spreading depression, occur spontaneously during 5 days following brain implant surgery in rats. These potentials are accompanied by reductions in multiple nerve cell activity and reductions in behavioral motility. The method used in this study provides a tool for evaluating recovery from neurosurgical trauma or other brain injuries, and for testing procedures that facilitate or impede this process.
Response of the Equatorial Countercurrent to the Subtropical Atmosphere
Authors: Namias Jerome
Published: October 2006

The strength of the equatorial countercurrent of the North Pacific and associated variations in sea surface temperatures at its eastern extremity off Central America are related to the zonal wind flow in the remote subtropical atmosphere with lags of as much as 8 months between wind and temperature.
Glucodynamic Hormones Modify the Recovery Period after Lateral Hypothalamic Lesions
Authors: Balagura Saul , Harrell Lindy , Ralph Timothy
Published: October 2006

The period of recovery after bilateral electrolytic lesions of the lateral hypothalamus in rats is shortened if insulin is given for 5 days before surgery, and is lengthened if glucagon is given during the preoperative period.
Ground-Based Thermal Infrared Surveys as an Aid in Predicting Volcanic Eruptions in the Cascade Range
Authors: Lange Ian M. , Avent Jon C.
Published: October 2006

Detailed, ground-based thermal surveys of selected slopes of Mt. Rainier and Mt. Lassen have provided quantitative data for the construction of thermal contour maps of portions of the flanks of these volcanoes. Preliminary surveys substantiate the existence of one suspected thermal anomaly on Mt. Rainier.
Electromagnetic Separation of Isotopes at Oak Ridge
Authors: Love L. O.
Published: October 2006

In 1960 I attended a European conference on isotope separation, after which I visited the Niels Bohr Institute in Copenhagen. A staff member there ventured the opinion that the separation of isotopes will be first on the list of important contributions to the peaceful uses of the atom when the Atomic Energy Commission's memoirs are written in the year 2000.

In 1968 the AEC Division of Research contracted with the National Research Council of the National Academy of Sciences to conduct a review of the AEC program for the separation of stable isotopes by electromagnetic and thermal diffusion methods. This ad hoc panel comprised seven scientists from the fields of chemistry, classical physics, geochemistry, geophysics, medicine, and physics. In their final report on national uses and needs for separated stable isotopes, they referred to the store of separated isotopes as a "real national asset that attains increasing value as science and technology develop" and recommended "continuation of the program as a national resource of great value to the United States."

Later, in a discussion of this report with A. M. Weinberg, J. Koch, himself a pioneer in electromagnetic isotope separation and member of the Danish Atomic Energy Program, said he would correct the statement that the Oak Ridge electromagnetic facility is a "national asset" to read "international asset."

From my narrow viewpoint after an extended and complete engrossment with this program for so many years, it is gratifying to learn that such men as those mentioned above share my belief that the work has indeed been worthwhile.
State of Equilibrium of the West Antarctic Inland Ice Sheet
Authors: Whillans Ian M.
Published: October 2006

Data from a traverse connecting Byrd Station, Antarctica, with the local ice divide allow calculation of the mean volume flux at points along the traverse. This is compared with current rates of surface accretion upstream from each point. Near the ice divide the ice sheet seems to be in equilibrium, but near Byrd Station the volume flux is in excess of that needed for ice sheet equilibrium by at least 15 percent. The discrepancy may exist because the traverse does not follow the ice flow exactly or because ice flow at depth is very complex. Although neither of the foregoing possibilities can be disproved, it seems most likely that the discrepancy is due to ice sheet thinning, as has previously been suggested by work on oxygen isotope ratios and temperature in the boreholes at Byrd Station. This thinning probably started at the end of the Wisconsin/Würm glaciation. Causes for the thinning are discussed.
Ocean Current Monitoring Employing a New Satellite Sensing Technique
Authors: Strong A. E. , DeRycke R. J.
Published: October 2006

The very-high-resolution radiometer on the NOAA-2 (National Oceanic and Atmospheric Administration) satellite has recently obtained imagery in the visible channel containing sunglint over a major portion of the coastal waters off the eastern seaboard of the United States. An abrupt change in surface roughness has been observed at the shoreward edge of the Gulf Stream Current from Florida to Cape Hatteras that results from the opposition of waves propagating against the flow of the Gulf Stream.
Dopaminergic Terminals in the Rat Cortex
Authors: Thierry A. M. , Blanc G. , Sobel A. , Stinus L. , Glowinski J.
Published: October 2006

The destruction of ascending noradrenergic pathways by bilateral microinjections of 6-hydroxydopamine made laterally to the pedunculus cerebellaris superior completely abolished the in vitro synthesis of [
3
H]norepinephrine from L-[
3
H]tyrosine in slices and in synaptosomes of the rat cortex. However, normal [
3
H]dopamine synthesis could still be observed in both cortical preparations from animals with lesions. These results provide the first biochemical support for the existence of dopaminergic terminals independent of noradrenergic terminals in the rat cortex.
Collagen Synthesis: Localization of Prolyl Hydroxylase in Tendon Cells Detected with Ferritin-Labeled Antibodies
Authors: Olsen Bjørn R. , Berg Richard A. , Kishida Yasuo , Prockop Darwin J.
Published: October 2006

An improved procedure was employed for linking ferritin to antibodies against prolyl hydroxylase, the enzyme that synthesizes the hydroxyproline in collagen. By electron microscopy, the enzyme was then found to be localized in cisternae of the rough endoplasmic reticulum of embryonic tendon cells; this indicates that hydroxylation of proline occurs while newly synthesized polypeptides are fed into the cisternae.
Chimpanzee Spatial Memory Organization
Authors: Menzel Emil W.
Published: October 2006

Juvenile chimpanzees, carried around an outdoor field and shown up to 18 randomly placed hidden foods, remembered most of these hiding places and the type of food that was in each. Their search pattern approximated an optimum routing, and they rarely rechecked a place they had already emptied of food.
Hyperactivity and Brain Catecholamines in Lead-Exposed Developing Rats
Authors: Sauerhoff Mitchell W. , Michaelson I. Arthur
Published: October 2006

Newborn rats that suckled mothers eating a diet containing 4 percent lead carbonate display hyperactivity, aggressiveness, and excessive stereotyped behavior starting at 4 weeks of age. There is an eightfold increase in the concentration of lead in brain, no change in norepinephrine, but a 20 percent decrease in dopamine relative to coetaneous controls. This suggests a relationship between central nervous system dysfunction due to lead and dopamine metabolism in brain.
The Relative Operating Characteristic in Psychology
Authors: Swets John A.
Published: October 2006

The clinician looking, listening, or feeling for signs of a disease may far prefer a false alarm to a miss, particularly if the disease is serious and contagious. On the other hand, he may believe that the available therapy is marginally effective, expensive, and debilitating. The pilot seeing the landing lights only when they are a few yards away may decide that his plane is adequately aligned with the runway if he is alone and familiar with that plight. He may be more inclined to circle the field before another try at landing if he has many passengers and recent memory of another plane crashing under those circumstances. The Food and Drug administrator suspecting botulism in a canned food may not want to accept even a remote threat to the public health. But he may be less clearly biased if a recent false alarm has cost a canning company millions of dollars and left some damaged reputations. The making of almost any fine discrimination is beset with such considerations of probability and utility, which are extraneous and potentially confounding when one is attempting to measure the acuity of discrimination per se.

The ROC is an analytical technique, with origins in statistical decision theory and electronic detection theory, that quite effectively isolates the effects of the observer's response bias, or decision criterion, in the study of discrimination behavior. This capability, pursued through a century of psychological testing, provides a relatively pure measure of the discriminability of different stimuli and of the capacity of organisms to discriminate. The ROC also treats quantitatively the response, or decision, aspects of choice behavior. The decision parameter can then be functionally related to the probabilities of the stimulus alternatives and to the utilities of the various stimulus-response pairs, or to the observer's expectations and motivations. In separating and quantifying discrimination and decision processes, the ROC promises a more reliable and valid solution to some practical problems and enhances our understanding of the perceptual and cognitive phenomena that depend directly on these fundamental processes. In several problem areas in psychology, effects that were supposed to reflect properties of the discrimination process have been shown by the ROC analysis to reflect instead properties of the decision process.
Small Area Variations in Health Care Delivery
Authors: Wennberg John , Gittelsohn Alan
Published: October 2006

Health information about total populations is a prerequisite for sound decision-making and planning in the health care field. Experience with a population-based health data system in Vermont reveals that there are wide variations in resource input, utilization of services, and expenditures among neighboring communities. Results show prima facie inequalities in the input of resources that are associated with income transfer from areas of lower expenditure to areas of higher expenditure. Variations in utilization indicate that there is considerable uncertainty about the effectiveness of different levels of aggregate, as well as specific kinds of, health services.

Informed choices in the public regulation of the health care sector require knowledge of the relation between medical care systems and the population groups being served, and they should take into account the effect of regulation on equality and effectiveness. When population-based data on small areas are available, decisions to expand hospitals, currently based on institutional pressures, can take into account a community's regional ranking in regard to bed input and utilization rates. Proposals by hospitals for unit price increases and the regulation of the actuarial rate of insurance programs can be evaluated in terms of per capita expenditures and income transfer between geographically defined populations. The PSRO's can evaluate the wide variations in level of services among residents of different communities. Coordinated exercise of the authority vested in these regulatory programs may lead to explicit strategies to deal directly with inequality and uncertainty concerning the effectiveness of health care delivery. Population-based health information systems, because they can provide information on the performance of health care systems and regulatory agencies, are an important step in the development of rational public policy for health.
Polyol Accumulation in Galactosemic and Diabetic Rats: Control by an Aldose Reductase Inhibitor
Authors: Dvornik D. , Simard-Duquesne N. , Krami M. , Sestanj K. , Gabbay K. H. , Kinoshita J. H. , Varma S. D. , Merola L. O.
Published: October 2006

An orally active inhibitor of aldose reductase, 1,3-dioxo-1H-benz[
de
]isoquinoline-2(3H)acetic acid (AY-22,284), prevented cataractous changes in cultured lenses exposed to high concentrations of galactose. When given orally, AY-22,284 markedly decreased the accumulation of polyols in the lenses and sciatic nerves of galactosemic rats and rats with streptozotocin-induced diabetes. In addition, treatment of galactosemic rats with AY-22,284 effectively suppressed the formation of cataracts.
Von Willebrand Factor: Dissociation from Antihemophilic Factor Procoagulant Activity
Authors: Weiss Harvey J. , Hoyer Leon W.
Published: October 2006

Factor VIII corrects both the clotting defect in hemophilia A and an abnormality of platelet aggregation in von Willebrand's disease. These two activities of factor VIII (antihemophilic factor and von Willebrand factor) are both detected in the void volume when human plasma or cryoprecipitate is chromatographed on Bio-Gel 5M under conditions of isotonic salt concentration. In contrast, antihemophilic factor procoagulant activity is detected with proteins of lower molecular weight when the chromatography is performed with a buffer containing 0.8
M
NaCl. In this way, the two activities of factor VIII can be dissociated. It remains to be determined whether these components are separate molecules associated as a complex of high molecular weight in plasma or whether they are subunits of a complex macromolecule.
Aquatic Respiration: An Unusual Strategy in the Hellbender
Cryptobranchus alleganiensis alleganiensis
(Daudin)
Authors: Guimond Robert W. , Hutchison Victor H.
Published: October 2006

Separate and simultaneous determinations of aerial and aquatic gas exchange in the giant salamander,
Cryptobranchus alleganiensis alleganiensis
(Daudin) were made at 5°, 15°, and 25°C. The aquatic respiration of this animal accounts for over 90 percent of the total volume of oxygen consumed and 97 percent of the total volume of carbon dioxide released at all temperatures. The lungs of these individuals are large transparent sacs which are poor respiratory organs; the lungs probably function more as hydrostatic structures than as gas exchangers. This animal is the largest aquatic vertebrate that lacks gills and yet utilizes almost exclusively an aquatic mode of respiration. Specialized cutaneous modifications, a unique body form, and a peculiar behavioral mechanism are of considerable adaptative significance, and confer to the skin the effectiveness of a veritable "gill."
Quantum Low-Temperature Limit of a Chemical Reaction Rate
Authors: Goldanskii V. I. , Frank-Kamenetskii M. D. , Barkalov I. M.
Published: October 2006

The radiation-induced polymerization of formaldehyde has been studied in the solid state. The time of addition of one new link to a polymer chain increases exponentially in accordance with the Arrhenius law at 140 to 80 K, but approaches a constant value (approximately 10
-2
second) at temperatures below 10 K. Thus, a low-temperature limit to a chemical reaction rate has been observed. It is interpreted as a quantum effect caused by tunneling from the zero vibration level of the initial state, and a semiquantitative theory is given. The phenomenon should be taken into account for understanding tunneling of electrons in biological systems when such tunneling is accompanied by conformational changes. It could also be significant in slow, exothermic chemical reactions at low and ultralow temperatures, which may have had a role in chemical and biological evolution (cold prehistory of life?).
Intrinsic Oscillations of Neocortex Generated by Layer 5 Pyramidal Neurons
Authors: Silva Laurie R. , Amitai Yael , Connors Barry W.
Published: October 2006

Rhythmic activity in the neocortex varies with different behavioral and pathological states and in some cases may encode sensory information. However, the neural mechanisms of these oscillations are largely unknown. Many pyramidal neurons in layer 5 of the neocortex showed prolonged, 5- to 12-hertz rhythmic firing patterns at threshold. Rhythmic firing was due to intrinsic membrane properties, sodium conductances were essential for rhythmicity, and calcium-dependent conductances strongly modified rhythmicity. Isolated slices of neocortex generated epochs of 4- to 10-hertz synchronized activity when
N
-methyl-D-aspartate receptor-mediated channels were facilitated. Layer 5 was both necessary and sufficient to produce these synchronized oscillations. Thus, synaptic networks of intrinsically rhythmic neurons in layer 5 may generate or promote certain synchronized oscillations of the neocortex.
D1 Dopamine Receptors in Prefrontal Cortex: Involvement in Working Memory
Authors: Sawaguchi Toshiyuki , Goldman-Rakic Patricia S.
Published: October 2006

The prefrontal cortex is involved in the cognitive process of working memory. Local injections of SCH23390 and SCH39166, selective antagonists of the D1 dopamine receptor, into the prefrontal cortex of rhesus monkeys induced errors and increased latency in performance on an oculomotor task that required memory-guided saccades. The deficit was dose-dependent and sensitive to the duration of the delay period. These D1 antagonists had no effect on performance in a control task requiring visually guided saccades, indicating that sensory and motor functions were unaltered. Thus, D1 dopamine receptors play a selective role in the mnemonic, predictive functions of the primate prefrontal cortex.
Lead Pica Produced in Rats
Authors: Snowdon Charles T. , Sanderson Blythe A.
Published: October 2006

Weanling rats eating a low calcium diet voluntarily ingested lead acetate solutions in much greater proportions than did iron-deficient or control weanlings. This increased ingestion occurred even with high concentrations of lead acetate which normal weanlings found extremely aversive. Chronic injections of lead acetate into weanlings did not change lead ingestion, indicating an absence of behavioral regulation of body lead levels. Female lead-injected weanlings did show a significant increase in calcium ingestion. Calcium deficiency may be one component of lead pica.
Particle Concentration in the Asteroid Belt from Pioneer 10
Authors: Soberman R. K. , Neste S. L. , Lichtenfeld K.
Published: October 2006

The spatial concentration and size distribution for particles measured by the asteroid/meteoroid detector on Pioneer 10 between 2 and 3.5 astronomical units are presented. The size distribution is from about 35 micrometers to 10 centimeters. The exponent of the size dependence varies from approximately -1.7 for the smallest to approximately -3.0 for the largest size measured.
Reduction of Ferricytochrome c by Some Free Radical Agents
Authors: Shafferman Avigdor , Stein Gabriel
Published: October 2006

Fast pulse radiolysis and kinetic spectroscopy were used to rapidly generate a variety of free radicals in situ and study their reactions with ferricytochrome c in the time range 10
-6
to 1 second. The radicals included
t
-butanol, which is inert to ferricytochrome c; malate, lactate, and ethanol, which react with it relatively slowly but are completely utilized in reducing it to ferrocytochrome c; and hydrated electrons and hydrogen atoms, which react with it very rapidly but yield ferrocytochrome c only in part, showing intramolecular consecutive reactions and further attack on the ferrocytochrome c protein. From a detailed comparison between malate and hydrogen atoms it is argued that malate reacts directly and selectively with a specific part of the ferricytochrome c surface while hydrogen atoms react with other parts of the protein too, yielding radicals which in part transfer intramolecularly to yield ferrocytochrome c.
Mycoplasma-Like Structures in the Aquatic Fungus
Aphanomyces astaci
Authors: Heath I. Brent , Unestam Torgny
Published: October 2006

The hyphae of a nonzoosporulating strain of
Aphanomyces astaci
contain numerous structures which most closely resemble published micrographs of certain mycoplasmas. Two normal strains of the same species do not contain these mycoplasma-like bodies.
Serotonin Storage in Platelets: Estimation of Storage-Packet Size
Authors: Costa Jonathan L. , Reese Thomas S. , Murphy Dennis L.
Published: October 2006

Storage-body diameter and volume, and the number of molecules of serotonin contained in a storage body, were estimated for blood platelets. In the human, 5.23 × 10
5
molecules of serotonin are contained in a storage body 198 nanometers in diameter, while in the cat, 31.2 × 10
5
molecules of this amine are contained in a storage body 298 nanometers in diameter.
Excitability Changes in Cat Lateral Geniculate Cells during Saccadic Eye Movements
Authors: Noda Hiroharu , Adey W. Ross
Published: October 2006

The excitability of lateral geniculate cells to orthodromic volleys decreased during saccadic eye movements. This decrease was caused by retinal impulses generated by a quick displacement of the image of the visual field associated with eye movements. This may be a mechanism for saccadic suppression.
Tip Growth in
Micrasterias
Authors: Lacalli Thurston , Acton A. B.
Published: October 2006

Methylation of polysaccharides in the growing primary wall of
Micrasterias
is localized at specific points on the wall which, by analogy with hyphal growth in fungi, are sites of maximum wall extension. Rather than being a direct cause of extension at these points, methylation may indicate an incorporation of hemicellulosic matrix substance that accompanies extension.
DDE: Its Presence in Peregrine Eggs in 1948
Authors: Peakall David B.
Published: October 2006

DDE has been eluted from the dried membranes of peregrine eggshells collected in California from 1948 to 1950, and identified by gas-liquid chromatography.
Survival at Extreme Altitude: Protective Effect of Increased Hemoglobin-Oxygen Affinity
Authors: Eaton John W. , Skelton T. D. , Berger Elaine
Published: October 2006

Decreased hemoglobin-oxygen affinity is thought to be of adaptive value to humans and nonindigenous animals at high altitude. To test this, hemoglobin-oxygen affinity was modified by carbamoylation of hemoglobin in rats. Exposure of control (low oxygen affinity) and experimental (high oxygen affinity) animals to a pressure equivalent to high altitude revealed that increased, rather than decreased, hemoglobin-oxygen affinity will permit survival at greatly reduced environmental oxygen pressures.
Cantharidin: Potent Feeding Deterrent to Insects
Authors: Carrel James E. , Eisner Thomas
Published: October 2006

Cantharidin, the well-known terpenoid compound from the blood of blister beetles (and active principle of Spanish fly), is a feeding deterrent to insects, effective at a concentration of 10
-5
molar.
Osmotic Gradients across Snail Epidermis: Evidence for a Water Barrier
Authors: Machin J.
Published: October 2006

Cryoscopic analysis of frozen sections provided indirect evidence for the presence of a waterproof layer limiting evaporation from living epithelial cells in dormant land snails.
Selenium Biochemistry
Authors: Stadtman Thressa C.
Published: October 2006

The toxicity of selenium to animals and plants has been known and extensively documented since the 1930's, but it is only during the past 15 years that selenium has also been shown to be an essential micronutrient for animals and bacteria. Very little is known about the specific role or roles of selenium and, to date, there are only three enzyme-catalyzed reactions that have been shown to require the participation of a selenium-containing protein. These are the reactions catalyzed by (i) formate dehydrogenase of bacteria, (ii) glycine reductase of clostridia, and (iii) glutathione peroxidase of erythrocytes. The common denominator of these selenium-dependent processes is that they are all oxidation-reduction reactions. A fourth selenoprotein has been isolated from skeletal muscle of sheep but its catalytic function has not been identified. The form in which selenium occurs in these selenoproteins is unknown. The selenoprotein of clostridial glycine reductase contains selenium in a covalently bound form. Studies in progress indicate that this may be an organoselenium compound not previously detected in nature. Identification of the chemical nature of selenium in proteins participating in electron transport processes should enable us to determine its specific role and to understand the basic defects in certain cardiac and skeletal muscle degenerative diseases which are selenium-deficiency syndromes. The greater availability and ease of isolation of the selenoprotein of the bacterial glycine reductase system makes this the biological material of choice for studies on the mechanism of action of selenium. An added attractive feature of this system is that it can conserve the energy made available by the reductive deamination of glycine in a biologically useful form by synthesizing ATP.
Ecto-Enzyme of Granulocytes: 5′-Nucleotidase
Authors: DePierre Joseph W. , Karnovsky Manfred L.
Published: October 2006

The 5′-nucleotidase of guinea pig polymorphonuclear leukocytes is localized exclusively on the plasma membrane of intact cells. The active site of this enzyme faces the external medium, not the cytoplasm.
Progesterone Binding to Hen Oviduct Genome: Specific Versus Nonspecific Binding
Authors: Spelsberg T. C. , Pikler G. M. , Webster R. A.
Published: October 2006

Data are presented to explain discrepancies in the literature involving the in vitro binding of steroid receptor complexes to isolated nuclei and chromatin. The type of binding in vitro of the progesterone-receptor complex to nuclei, chromatin, or DNA of hen organs is largely determined by the ionic strength of the medium. Low ionic conditions (0.01 to 0.05 molar potassium chloride) result in a nonspecific, nonsaturable binding, while high ionic conditions (0.15 to 0.20 molar potassium chloride) create a tissue-specific, saturable binding. Pure DNA binds the steroid receptor complex extensively in low salt but very little in the higher salt conditions.
γ-Glutamyl Transpeptidase in Brain Capillaries: Possible Site of a Blood-Brain Barrier for Amino Acids
Authors: Orlowski Marian , Sessa Grazia , Green Jack Peter
Published: October 2006

A fraction containing capillaries and rich in γ-glutamyl transpeptidase was isolated from homogenates of bovine brain cortex by density gradient centrifugation. The enzyme was localized in the endothelial cells by a histochemical procedure. γ-Glutamyl transpeptidase may function in the transfer of some amino acids across the blood-brain barrier.
Follicle-Stimulating Hormone Secretion in the Female Rat: Cyclic Release Is Dependent on Circulating Androgen
Authors: Gay Vernon L. , Tomacari R. L.
Published: October 2006

In adult cyclic female rats, intravenous injections of an antiserum to testosterone prevented the continued increase in serum follicle-stimulating hormone (FSH) which normally occurs during the early morning hours of estrus. This treatment did not prevent the initial increases in serum FSH (and luteinizing hormone) which occur during the critical period (1400 to 2000 of proestrus), nor did it interfere with subsequent ovulation. These observations indicate the existence of two separate mechanisms for preovulatory FSH release in the rat and implicate circulating testosterone as the stimulus for continued secretion of FSH during estrus.
Prostaglandins Stimulate Thyroid Function in Pregnant Women
Authors: Shenkman L. , Imai Y. , Kataoka K. , Hollander C. S. , Wan L. , Tang S. C. , Avruskin T.
Published: October 2006

Intravaginal or intravenous administration of prostaglandin F2αto pregnant women produced significant elevations of plasma triiodothyronine and thyroxine concentrations, but no rise of thyrotropin. These observations are consistent with those of previous in vitro studies indicating that prostaglandins can act directly on the thyroid gland to stimulate thyroid hormone synthesis or release, or both.
Identification of a Ventral Scent Marking Pheromone in the Male Mongolian Gerbil (
Meriones unguiculatus
)
Authors: Thiessen D. D. , Regnier Fred E. , Rice Maureen , Goodwn Michael , Isaacks Nancy , Lawson Nancy
Published: October 2006

Sebum from the ventral scent marking gland of the male Mongolian gerbil was fractionated and tested for its ability to elicit behavioral response in a conditioning task and in a stimulus preference situation. The active fraction was identified as phenylacetic acid; both it and a synthetic sample elicited the same behavioral response. Phenylacetic acid appears to be a major pheromone of the male Mongolian gerbil.
Jupiter's Ionosphere: Prospects for Pioneer 10
Authors: Atreya S. K. , Donahue T. M. , McElroy Michael B.
Published: October 2006

Model Jovian ionospheres are constructed for comparison with Pioneer 10 results. Electron density maxima are predicted at a level approximately 220 kilometers above an assumed reference height where the hydrogen density is 10
16
molecules per cubic centimeter. It may be possible to use observations of the electron density to locate the turbopause. Attention is drawn to a possible strong source of ionized sodium from Io which might lead to large electron densities at low altitudes.
Oxygen Binding in Cyanmet Hybrid and Normal Hemoglobins: Applicability of Sequential and Two-State Concerted Models
Authors: Minton Allen P.
Published: October 2006

The cyanmet hybrid hemoglobins α
2
β
+CN
2
and α
+CN
2
β
2
are widely held to be similar or equivalent in structure and subunit interactions to the partially oxygen-liganded species α
2
(β ⋅ O
2
)
2
and (α ⋅ O
2
)
2
β
2
, respectively. An analysis of precise data on oxygen binding to the cyanmet hybrids and normal hemoglobin shows that if this is the case, then cooperative ligand binding in hemoglobin is more properly described by some model of the sequential type than by any two-state concerted model.
Illusory Correlation of Brightness Enhancement and Transients in the Nervous System
Authors: Wasserman Gerald S. , Kong King-Leung
Published: October 2006

Short light flashes can appear brighter than longer flashes. This brightness enhancement has often been attributed to neural transients occurring shortly after stimulus onset. This attribution assumes an equivalence between the totality of the response to a stimulus of a given duration and the instantaneous response at a given time after stimulus onset. Recordings from
Limulus
photoreceptors indicate that this attribution is an example of illusory correlation.
Angiotensin II- and Angiotensin III-Induced Aldosterone Release in vivo in the Rat
Authors: Campbell William B. , Brooks Stephen N. , Pettinger William A.
Published: October 2006

The potential role of angiotensin II and its heptapeptide metabolite, des-aspartyl-angiotensin II, was studied in the conscious unanesthetized rat. Aldosterone release was induced by both peptides at physiologic doses (0.72 nanogram per minute). [1-Sarcosyl-8-alanyl]-angiotensin II (P-113 inhibited angiotensin II more effectively than des-aspartyl-angiotensin II (101 percent as compared to 82 percent). These results indicate that angiotensin controls aldosterone release in the rat and that des-aspartyl-angiotensin II (that is, angiotensin III) may be important in this sequence.
Nuclear Magnetic Resonance Studies and Water "Ordering" in the Crystalline Lens
Authors: Neville Margaret C. , Paterson Christopher A. , Rae James L. , Woessner Donald E.
Published: October 2006

Nuclear magnetic resonance studies of the relaxation times of the water in the crystalline lens show that, as in all interfacial systems, these parameters are markedly reduced from their values in pure water, that T
2
is less than T
1
, and that both depend on water content. Determination of diffusion coefficients and studies on physiologically inert lenses indicate that reduced relaxation times do not provide direct evidence for ordering of the bulk of the cell water.
Carbonate Ion-Selective Membrane Electrode
Authors: Herman H. B. , Rechnitz G. A.
Published: October 2006

A liquid membrane electrode has been developed with Nernstian response and a high selectivity for carbonate ion. The electrode responds rapidly to carbonate in the 10
-2
M
to 10
-6
M
range with a selectivity for carbonate over chloride, sulfate, and phosphate of at least 10
3
and negligible bicarbonate response. The electrode properties appear to be suited to chemical, biological, and oceanographic measurements.
Satellite Photograph Presents First Comprehensive View of Local Wind: The Santa Ana
Authors: Bowden Leonard W. , Huning James R. , Hutchinson Charles F. , Johnson Claude W.
Published: October 2006

The photograph of the 1 January 1973 Santa Ana wind condition reveals local atmospheric dynamics rarely recorded on satellite imagery. The Santa Ana wind implies very specific weather conditions for the Los Angeles coastal lowland. Destructive land uses, in part, provided the material visible in the dust plumes.