bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron Population Parameters from Least-Squares Refinement of X-ray Diffraction Data
Authors: Coppens P. , Csonka L. , Willoughby T. V.
Published: October 2006

A least-squares refinement of x-ray diffraction data has been developed in which the parameters are the populations of atomic orbital products describing the molecular electron density distribution. The procedure is applied to α-oxalic acid dihydrate and cyanuric acid. Complementary structural information obtained by neutron diffraction has been used. In the absence of complementary information, the method allows simultaneous determination of structural and charge-density parameters. There is an indication of a migration of charge from the
p
π
to the
p
σ
orbitals in both molecules.
Image-Formation Technique for Scanning Electron Microscopy and Electron Probe Microanalysis
Authors: Heinrich Kurt F. J. , Fiori Charles , Yakowitz Harvey
Published: October 2006

A technique is described for producing improved topographic images on the scanning electron microscope and the scanning electron probe microanalyzer. In this technique, the brightness of the oscilloscope is modulated by a signal obtained by mixing the signal (from secondary electrons or target current) with its first derivative. This enhances minor topographic features which are poorly reproduced in the conventional technique.
Senescence and Genetic Load: Evidence from
Tribolium
Authors: Sokal Robert R.
Published: October 2006

After 40 generations in which young adults were killed shortly after the onset of reproduction, strains of
Tribolium castaneum
with significantly decreased median longevity evolved. These findings support the hypothesis that the longevity of a species is controlled by genetic factors, and represents a compromise between selection for longer reproductive period and the limit set by environmental hazards.
Pineal Gland: Dibutyryl Cyclic Adenosine Monophosphate Stimulation of Labeled Melatonin Production
Authors: Klein David C. , Berg Gerald R. , Weller Joan , Glinsmann Walter
Published: October 2006

In organ cultures of intact rat pineal glands, N
6
O
2
′-dibutyryl adenosine 3′,5′-monophosphate stimulates the conversion of tritiated trytophan to tritiated melatonin, as does L-norepinephrine. Potential sites of stimulation of melatonin production by dibutyryl cyclic adenosine monophosphate are discussed, based on observations that the dibutyryl analog also stimulates the conversion of serotonin labeled with carbon-14 to carbon-14-labeled melatonin without altering hydroxyindole-
O
-methyl transferase activity or intracellular accumulation of serotonin labeled with carbon-14.
Pattern Formation During Animal Development
Authors: Melton D. A.
Published: October 2006

At the beginning of this century, embryologists defined the central problems of developmental biology that remain today. These questions include how differentiated cells arise and form tissues and organs and how pattern is generated. In short, how does an egg give rise to an adult? In recent years, the application of molecular biology to embryological problems has led to significant advances and recast old problems in molecular and cellular terms. Although not necessarily comprehensive, this idiosyncratic review is intended to highlight selected findings and indicate where there are important gaps in our knowledge for those less than familiar with developmental biology.
Steroid Hormones: Effects on Adenyl Cyclase Activity and Adenosine 3′,5′-Monophosphate in Target Tissues
Authors: Rosenfeld M. G. , O'Malley B. W.
Published: October 2006

The adenyl cyclases of chick oviduct and rat prostate were not stimulated by estrogen and testosterone, respectively, suggesting that growth and differentiation of these target tissues are not mediated by adenosine 3′,5′-monophosphate. Estrogen acutely activated adenyl cyclase in the castrate rat uterus, but this was prevented by administration of DL-propranolol, suggesting that the effect was mediated by catecholamines. Progesterone produced a delayed stimulation of oviduct adenyl cyclase preceding and concomitant with the induction of synthesis of avidin.
Intermodal Equivalence of Stimuli in Apes
Authors: Davenport Richard K. , Rogers Charles M.
Published: October 2006

Orang-utans and chimpanzees can discriminate between two objects on the basis of tactile cues and select the one that matches a visually presented sample.
Carbon-13 and Oxygen-18 in Dinosaur, Crocodile, and Bird Eggshells Indicate Environmental Conditions
Authors: Follinsbee R. E. , Fritz P. , Krouse H. R. , Robblee A. R.
Published: October 2006

We have gathered, from the nests of dinosaurs, and living and fossil birds, some evidence of the environment in which these creatures lived. However, our isotope determinations suggest it will be impossible to resolve the problem as to whether the dinosaurs were warm- or cold-blooded from the oxygen and carbon isotope content of their shells.
The Dominant W
42
Spotting Phenotype Results from a Missense Mutation in the c-
kit
Receptor Kinase
Authors: Tan Jimmy C. , Nocka Karl , Ray Prabir , Traktman Paula , Besmer Peter
Published: October 2006

The murine
white spotting
locus (
W
) is allelic with the proto-oncogene c-
kit
, which encodes a transmembrane tyrosine protein kinase receptor for an unknown ligand. Mutations at the
W
locus affect various aspects of hematopoiesis and the proliferation and migration of primordial germ cells and melanoblasts during development to varying degrees of severity. The
W
42
mutation has a particularly severe effect in both the homozygous and the heterozygous states. The molecular basis of the
W
42
mutation was determined. The c-
kit
protein products in homozygous mutant mast cells were expressed normally but displayed a defective tyrosine kinase activity in vitro. Nucleotide sequence analysis of mutant complementary DNAs revealed a missense mutation that replaces aspartic acid with asparagine at position 790 in the c-
kit
protein product. Aspartic acid-790 is a conserved residue in all protein kinases. These results provide an explanation for the dominant nature of the
W
42
mutation and provide insight into the mechanism of c-
kit
-mediated signal transduction.
Pituitary Serotonin Content: Effects of Melatonin or Deprivation of Water
Authors: Piezzi R. S. , Wurtman R. J.
Published: October 2006

Relatively high concentrations of serotonin are found in the three regions of the rat pituitary gland. Administration of melatonin causes a selective increase in the serotonin concentration of the pars intermedia; deprivation of water for 5 days causes a selective decrease in the serotonin concentrations of the neural lobe and pars distalis.
Attack Autotomy: A Defense against Predators
Authors: Robinson Michael H. , Abele Lawrence G. , Robinson Barbara
Published: October 2006

The response of five species of crabs to simulated predator attack was examined. Two terrestrial species autotomized their chelipeds after the chelae were firmly attached to the predator. Selection for attack autotomy is balanced by selection for retention of the cheliped whenever the cheliped is important in social or maintenance functions.
Desmosterol as the Major Sterol in L-Cell Mouse Fibroblasts Grown in Sterol-Free Culture Medium
Authors: Rothblat G. H. , Burns C. H. , Conner R. L. , Landrey J. R.
Published: October 2006

The principal sterol synthesized by L-cell mouse fibroblasts is desmosterol. Cholesterol was not detected in these cells when they were grown in a sterol-free culture medium. These findings indicate that, in cells, cholesterol can be replaced by desmosterol. Sterol analyses of six other tissue culture cell lines revealed cholesterol synthesis.
Enzyme Replacement in Fabry's Disease, an Inborn Error of Metabolism
Authors: Mapes Carol A. , Anderson Richard L. , Sweeley Charles C. , Desnick Robert J. , Krivit William
Published: October 2006

Two patients with Fabry's disease were infused with normal plasma to provide active enzyme (ceramide trihexosidase) for hydrolysis of the plasma substrate, galactosylgalactosylglucosylceramide. Maximum ceramide trihexosidase activity occurred 6 hours after infusion of the plasma, attaining a level approximately 150 percent of that in normal plasma; enzymatic activity was detectable for 7 days. The amount of accumulated substrate in the plasma of these recipients decreased about 50 percent on day 10 after infusion. Thus, periodic replacement of ceramide trihexosidase activity in the plasma of patients with Fabry's disease might lead to consistently lower amounts of substrate in the plasma and a decrease in its rate of accumulation in tissues.
Antarctic Glaciation during the Tertiary Recorded in Sub-Antarctic Deep-Sea Cores
Authors: Margolis Stanley V. , Kennett James P.
Published: October 2006

Study of 18 Cenozoic South Pacific deep-sea cores indicates an association of glacially derived ice-rafted sands and relatively low planktonic foraminiferal diversity with cooling of the Southern Ocean during the Lower Eocene, upper Middle Eocene, and Oligocene. Increased species diversity and reduction or absence of ice-rafted sands in Lower and Middle Miocene cores indicate a warming trend that ended in the Upper Miocene. Antarctic continental glaciation appears to have prevailed throughout much of the Cenozoic.
Visual Discrimination of Movement: Midbrain or Forebrain?
Authors: Hamilton Charles R. , Lund Jennifer S.
Published: October 2006

Monkeys whose optic chiasm and forebrain commissures had been sectioned and control monkeys with only the optic chiasm cut were tested for interocular transfer of discriminations based on direction of movement. Only the control animals showed transfer to the untrained eye, which suggests that discrimination of movement, like pattern, is a function strongly dependent on the cortex.
Hybrid Cell Line from a Cloned Immunoglobulin-Producing Mouse Myeloma and a Nonproducing Mouse Lymphoma
Authors: Mohit Behzad , Fan Kang
Published: October 2006

A hybrid cell line was established by cell fusion between a cloned Balb/c myeloma that is resistant to 8-azaguanine and produces immunoglobulin (γG and free kappa chain) and C57BL/6N lymphoma that is resistant to bromodeoxyuridine and does not produce immunoglobulins. The hybrid cells contained the membrane antigens of both parents; they synthesized free kappa chain; no synthesis of γG (γ
2a
) heavy chain was detected.
Ribosomal RNA Synthesis and the Multiple, Atypical Nucleoli in Cleaving Embryos
Authors: Emerson Charles P. , Humphreys Tom
Published: October 2006

The rate of ribosomal RNA synthesis per nucleus in cleaving sea urchin embryos is similar to the rate at later embryonic stages. The multiple, atypical nucleoli, present in early embryos and usually attributed to decreased ribosomal RNA synthesis, are beginning stages of nucleolar formation. Full nucleolar development requires more time than the brief interphase of the rapidly dividing cells.
Chemical-Cue Preferences of Newborn Snakes: Influence of Prenatal Maternal Experience
Authors: Burghardt Gordon M.
Published: October 2006

Newborn garter snakes
(Thamnophis sirtalis)
responded similarly to worm and fish surface extracts regardless of whether the mothers were fed exclusively on fish or worms during the gestation period. Worm extract was the more effective. This result is in contrast with the easy modifiability of chemical-cue preferences in young snakes after birth. The initial stimulus control of the attack response in newborn snakes thus seems relatively unmodifiable.
Prevention of Xenograft Rejection by Masking Donor HLA Class I Antigens
Authors: Faustman Denise , Coe Chuck
Published: October 2006

Destruction of target cells by cytotoxic T lymphocytes requires the presence of HLA (human lymphocyte antigen) class I antigens on the target cells for adhesion as well as for triggering of the antigen-specific T cell receptor. Rejection of xenogeneic human pancreatic islets and liver was circumvented by masking, before transplantation, donor antigens with F(ab')
2
antibody fragments to HLA class I or tissue-specific epitopes. This strategy eliminated the need for recipient immunosuppression and allowed islet xenograft survival beyond 200 days, as demonstrated functionally by C peptide secretion as well as by histology. These in vivo observations are consistent with the importance of donor HLA class I in eliciting graft rejection and have potential applicability to the successful transplantation of other HLA class I-bearing donor tissues.
Phosphoribosylpyrophosphate Overproduction, a New Metabolic Abnormality in the Lesch Nyhan Syndrome
Authors: Reem Gabrielle H.
Published: October 2006

The activity of phosphoribosylpyrophosphate synthetase and the rate of phosphoribosylpyrophosphate accumulation are significantly increased in cultured lymphocytes of Lesch Nyhan patients deficient in hypoxanthine guanine phosphoribosyltransferase and in a clone of mutagen-induced, hypoxanthine guanine phosphoribosyltransferase deficient human lymphocytes. The increase in phosphoribosylpyrophosphate synthetase activity is the cause of the abnormally high cellular phosphoribosylpyrophosphate content and possibly of the purine overproduction described in this syndrome.
Height and Antisocial Behavior in XY and XYY Boys
Authors: Hook Ernest B. , Kim Dong-Soo
Published: October 2006

The observed association of the XYY genotype with both (i) large height in childhood and (ii) institutionalization for antisocial behavior suggested that large size per se in childhood might tend to establish personality patterns leading to eventual incarceration for delinquency. To investigate this question, the height distributions of four groups of XY boys in institutions for nonpsychotic, nonretarded juvenile offenders were compared with the published standards as well as the predicted gaussian distributions calculated from the mean and variance of the age-adjusted heights of each group. In none of these groups was there evidence for an increased number of large individuals. But three XYY individuals in the same institutions all had heights greater than the 90th percentile of XY boys of the same race.
Language Production: Electroencephalographic Localization in the Normal Human Brain
Authors: McAdam Dale W. , Whitaker Harry A.
Published: October 2006

Slow negative potentials, which are at a maximum over Broca's area in the left hemisphere, were recorded when normal subjects spontaneously produced polysyllabic words. Bilaterally symmetrical potentials were seen with analogous, nonspeech control gestures. These potentials began up to 1 second before word or gesture articulation. These results are the first demonstration of localization of language production in normal human brain.
Preparation of High-Crystallinity Polyethylene at Low Pressures
Authors: Hara K. , Schonhorn H.
Published: October 2006

The preparation of highly crystalline polyethylene at low pressures is reported. With careful control of the substrate, the melting and crystallization schedule, and the physical state of the specimen (film thickness), it is possible to prepare polyethylene having a density in excess of 0.999 gram per cubic centimeter, a melting temperature of approximately 140°C, and a heat of fusion in excess of 70 calories per gram. The approach appears to be general and should be applicable to a wide variety of polymers.
Solar Radiation: Absence of Air Pollution Trends at Mauna Loa
Authors: Ellis Howard T. , Pueschel Rudolf F.
Published: October 2006

Measurements of solar radiation made at Mauna Loa, Hawaii, over a period of 13 years give no evidence that human activities affect atmospheric turbidity on a global scale. Short-term fluctuations in insolation appear to be associated with naturally produced tropospheric aerosols. The intrusion of volcanic dust into the stratosphere results in prolonged increases in atmospheric opacity due to the extended residence times of aerosols in the stratosphere.
Recent Volcanism and the Stratosphere
Authors: Cronin John F.
Published: October 2006

In the quiet years after the 1956 eruption of the Bezymianny volcano in central Kamchatka, it is doubtful that any volcano vented into the stratosphere until the 1963 eruptions of Agung (Bali), Trident (Alaska), and Surtsey (Iceland). From 1963 to the Hekla (Iceland) event in May 1970, two latitudinal belts of volcanoes have ejected ash and gases into the stratosphere. One belt is equatorial and the other is just below the Arctic Circle. The latter, where the tropopause is considerably lower, may have been the principal source of replenishment of volcanic dust and gases to the stratosphere. Submarine and phreatic volcanic eruptions may have been the sources of reported increase of water vapor in the stratosphere.
Visual Phenomena Noted by Human Subjects on Exposure to Neutrons of Energies Less than 25 Million Electron Volts
Authors: Budinger Thomas F. , Bichsel Hans , Tobias Cornelius A.
Published: October 2006

Six subjects reported multiple starlike flashes and short streaks on exposure to neutrons of energies up to 25 million electron volts. The probable mechanism is interaction with the retinal rods by proton recoils and by alpha particles released from neutron reactions with carbon and oxygen. These observations are similar to light flashes and streaks seen by astronauts who are exposed to high-energy cosmic rays on translunar flight.
Synthesis of 5
S
and 4
S
RNA in Metaphase-Arrested HeLa Cells
Authors: Zylber Ester A. , Penman Sheldon
Published: October 2006

The continued synthesis of both 5
S
and 4
S
RNA in metaphase-arrested HeLa cells is demonstrated; 5
S
RNA is apparently synthesized at approximately 74 percent of the interphase rate, while 4
S
RNA is synthesized at approximately one-third the rate. The ratio of uridine incorporation to RNA methylation is used to correct for the alteration in the specific activity of the pyrimidine pool during metaphase arrest.
Odor Incongruity and Chirality
Authors: Friedman Lester , Miller John G.
Published: October 2006

The enantiomers
R
-(-)- and
S
-(+)-carvone are the organoleptic constituents in oil of spearmint and caraway, respectively. Their odor distinctiveness has been unambiguously demonstrated by chemical interconversion, independent synthesis, and resolution. Odor differences between other chiral isomers were also firmly established.
Boron: Possible Role in Plant Metabolism
Authors: Rajaratnam J. A. , Lowry J. B. , Avadhani P. N. , Corley R. H. V.
Published: October 2006

Leaves of boron-deficient oil palm showed a total absence of the leucoanthocyanins usually present, well before onset of pathological symptoms. The association of boron with flavonoid synthesis is consistent with the otherwise anomalous situation that this element is essential for higher plants but not for animals or lower plants.
Summit Firn Caves, Mount Rainier, Washington
Authors: Kiver Eugene P. , Mumma Martin D.
Published: October 2006

Heat and steam from the crater fumaroles have melted over 5700 feet (1737 meters) of cave passage in the ice-filled east crater of Mount Rainier. The caves are in approximate balance with the present geothermal heat release. Future changes in the thermal activity of the summit cone will cause corresponding changes in cave passage dimensions, location, and ceiling and wall ablation features.
Regional Blood-Flow Changes during 72-Hour Avoidance Schedules in the Monkey
Authors: Forsyth Ralph P.
Published: October 2006

Systemic and regional blood-flow measurements were made in five restrained monkeys before and during 72 hours of continuous work on an avoidance schedule. Systemic arterial pressures were elevated throughout the stress, initially owing to an increase in cardiac output, and after 72 hours owing to an increase in total peripheral resistance. Changes in the resistance in skeletal muscle blood vessels were closely related to these changes in total peripheral resistance.
Women in Academia
Authors: Lewin Arie Y. , Duchan Linda
Published: October 2006

Although our study was conducted in only one physical science discipline, and although most of the individual tests did not yield statistically significant differences, the data consistently yielded a trend in the direction of the existence of discrimination against women in academia. This leads us to the tentative conclusion that when two equally qualified applicants are being considered for an academic position, a male would be chosen over a female. However, a woman with clearly superior qualifications, in competition with an average man, is likely to be recognized. The bias seems to hold especially for higher-quality schools, in departments with younger and newer chairmen, and for chairmen from schools located in the eastern and western parts of the country.

The underutilization of potentially qualified women in science represents lost opportunities to society and to science in terms of the overall goal of advancing science. To the extent that the bias reflects strongly held cultural norms, change will come slowly. However, structural changes within the institutions that employ and train women scientists may be achieved sooner through the active intervention of outside agencies, for example, the enforcement by the Department of Health, Education, and Welfare of the Equal Opportunities Act in colleges and universities (
19
). In addition, such federal grant-awarding agencies as the National Science Foundation and the National Institutes of Health could be given a mandate to make a special effort to identify and award grants and other forms of recognition to deserving women scientist.
Deep-Water Archeology
Authors: Bascom Willard
Published: October 2006

There is reason to believe that some old wooden ships on the deep-sea floor have survived for thousands of years without much change. They will not be covered with much sediment, and it will be possible to find them using new searching techniques. These are embodied in the system of the
Alcoa Seaprobe
, which is also equipped to identify and raise old ships.
Subhuman Primate Diploid Cells: Possible Substrates for Production of Virus Vaccines
Authors: Petricciani John C. , Hopps Hope E. , Lorenz Douglas E.
Published: October 2006

Results of a program for development of new cell lines suggest that it is possible to establish cell lines from both rhesus and African green monkeys which are comparable to diploid lines of human origin, and that these monkey lines should be candidates for use in the production of virus vaccines.
Single Neuron Activity in Cat Gigantocellular Tegmental Field: Selectivity of Discharge in Desynchronized Sleep
Authors: McCarley Robert W. , Hobson J. Allan
Published: October 2006

Ratios of discharge rates in desynchronized sleep to those in waking and synchronized sleep of gigantocellular neurons are five to ten times higher than are those of neurons in adjacent tegmental fields and 25 to 30 times higher than in other brain sites. This marked concentration of activity in desynchronized sleep is compatible with an active role of gigantocellular neurons in the generation of this sleep phase.
Cave Development during a Catastrophic Storm in the Great Valley of Virginia
Authors: Doehring D. O. , Vierbuchen R. C.
Published: October 2006

Observations made before and after a catastrophic storm support the conclusion that caves receiving storm recharge may be significantly developed in the vadose zone by the processes of mass transfer. These processes are greatly accelerated during times of major floods. Evidence indicates that in ancient times floods of similar magnitude have occurred.
Mariner 9 Ultraviolet Spectrometer Experiment: Stellar Observations
Authors: Lillie Charles F. , Bohlin Ralph C. , Molnar Michael R. , Barth Charles A. , Lane Arthur L.
Published: October 2006

Photoelectric spectra have been obtained for a number of early-type stars in the 1100- to 2000-angstrom region with the Mariner 9 ultraviolet spectrometer. The resonance lines of H I, Si IV, and C IV are easily identified, as are features due to C II, C III, Si III, Fe II, N IV. The absolute energy distribution derived from the data lie about 20 percent below those of OAO-2 in the 1200- to 2000-angstrom region.
Primordial Radioelements and Cosmogenic Radionuclides in Lunar Samples from Apollo 15
Authors: O'Kelley G. Davis , Eldridge James S. , Schonfeld E. , Northcutt K. J.
Published: October 2006

Two basalts, two breccias, and two soils from Apollo 15 were analyzed by nondestructive gamma-ray spectrometry. The concentrations of potassium, thorium, and uranium in the basalts were similar to those in the Apollo 12 basalts, but the potassium: uranium ratios were somewhat higher. Primordial radioelements were enriched in the soils and breccia, consistent with a two-component mixture of mare basalt and up to 20 percent foreign component (KREEP). The abundance patterns for cosmogenic radionuclides implied surface sampling for all specimens. The galactic cosmic-ray production rate of vanadium-48 was determined as 57 ± 11 disintegrations per minute per kilogram of iron. Cobalt-56 concentrations were used to estimate the intensity of the solar flare of 25 January 1971.
Venus: Topography Revealed by Radar Data
Authors: Campbell D. B. , Dyce R. B. , Ingalls R. P. , Pettengill G. H. , Shapiro I. I.
Published: October 2006

Surface height variations over the entire equatorial region on Venus have been estimated from extended series of measurements of interplanetary radar echo delays. Most notable is a mountainous section of about 3-kilometer peak height located at a longitude of 100 degrees (International Astronomical Union coordinate system). The eastern edge has an average inclination of about 0.5 degrees, which is unusually steep for a large-scale slope on Venus. The resolution of the radar measurements along the surface of Venus varied between about 200 and 400 kilometers with a repeatability in altitude determination generally between 200 and 500 meters. The mean equatorial radius was found to be 6050.0±0.5 kilometers.
Opossum Fetuses Grown in Culture
Authors: New D. A. T. , Mizell Merle
Published: October 2006

Opossum fetuses explanted at limb bud stages have been successfully grown in culture for periods up to 20 hours. Blood circulation was maintained, and organogenesis continued at about the same rate as in vivo.
Cyclic Nucleotide Phosphodiesterase: High Activity in a Mammalian Photoreceptor
Authors: Pannbacker R. G. , Fleischman D. E. , Reed D. W.
Published: October 2006

Purified outer segments of bovine rods exhibit phosphodiesterase activity against adenosine and guanosine cyclic 3′,5′-monophosphates (cyclic AMP and cyclic GMP). The enzyme hydrolyzed cyclic GMP more rapidly than cyclic AMP at low substrate concentrations. The presence of high phosphodiesterase activity in this highly specialized organelle suggests that this enzyme may function in control of cyclic nucleotide concentration during visual excitation or adaptation.
Scanning Electron Microscopy of the Human Fallopian Tube
Authors: Ferenczy Alex , Richart Ralph M. , Agate Frederic J. , Purkerson Mabel L. , Dempsey Edward W.
Published: October 2006

Fallopian tubes from women of reproductive and postmenopausal ages were examined by scanning electron microscopy. The surface topography of these Fallopian tubes is described and illustrated.
Phosphodiesterase in
Dictyostelium discoideum
and the Chemotactic Response to Cyclic Adenosine Monophosphate
Authors: Pannbacker R. G. , Bravard L. J.
Published: October 2006

A phosphodiesterase with a low Michaelis constant for cyclic adenosine monophosphate was found in the membrane fraction of the cellular slime mold. This activity was highest during the aggregation stage. Enzyme with similar properties was also secreted by the cells. Dithiothreitol inhibited both enzymes and potentiated the cellular response to cyclic adenosine monophosphate.
Thymus-Derived Lymphocytes: Humoral and Cellular Reactions Distinguished by Hydrocortisone
Authors: Segal Shraga , Cohen Irun R. , Feldman Michael
Published: October 2006

Lymphocytes derived from the thymus (T cells) take part in the induction of humoral antibody and also effect cell-mediated graft-versus-host reactions. Preliminary treatment of mice with hydrocortisone caused an inhibition of T-cell function in humoral immunity, while enhancing the graft-versus-host reactivity of the same population of spleen cells. This suggests that different types of T cells participate in cellular and humoral immune reactions.
Carbon Isotopic Studies of Organic Matter in Precambrian Rocks
Authors: Oehler Dorothy Z. , Schopf J. William , Kvenvolden Keith A.
Published: October 2006

Reduced carbon in early Precambrian cherts of the Fig Tree and upper and middle Onverwacht groups of South Africa is isotopically similar (the average value of δ
13
C
PDB
is -28.7 per mil) to photosynthetically produced organic matter of younger geological age. Reduced carbon in lower Onverwacht cherts (Theespruit formation) is anomalously heavy (the average value of δ
13
C
PDB
is -16.5 per mil). This discontinuity may reflect a major event in biological evolution.
Axons: Isolation from Mammalian Central Nervous System
Authors: DeVries George H. , Norton William T. , Raine Cedric S.
Published: October 2006

Centrifugation of a homogenate of white matter, in a solution of buffered sucrose containing salt, produces a floating layer of myelinated axons. When these are suspended in hypotonic buffer, the myelin swells and strips away from the axon. Axons are then separated from the myelin by centrifugation. The resulting preparation consists of a variable population of processes with lengths up to 200 micrometers and diameters between 0.3 and 5.0 micrometers. The axons contain neurofilaments and mitochondria, although no axolemma or neurotubules are evident. The preparation contains cerebroside and sulfatide, yet is essentially free of myelin.
Enrichment of Heavy Metals and Organic Compounds in the Surface Microlayer of Narragansett Bay, Rhode Island
Authors: Duce Robert A. , Quinn James G. , Olney Charles E. , Piotrowicz Stephen R. , Ray Barbara J. , Wade Terry L.
Published: October 2006

Concentrations of lead, iron, nickel, copper, fatty acids, hydrocarbons, and chlorinated hydrocarbons are enriched from 1.5 to 50 times in the top 100 to 150 micrometers of Narragansett Bay water relative to the bulk water 20 centimeters below the surface. Trace metal enrichment was observed in the particulate and organic fractions but not in the inorganic fraction. If these substances are concentrated in films only a few molecular layers thick on the water surface, the actual enrichment factor in the films may be well over 10
4
, resulting in extremely high localized pollutant concentrations in the surface microlayer.
Groundwater Contamination by Road Salt: Steady-State Concentrations in East Central Massachusetts
Authors: Huling Edwin E. , Hollocher Thomas C.
Published: October 2006

The average steady-state contamination of groundwater by road salt in the suburban area around Boston, on the assumption that current rates of application of salt will continue, is about 160 milligrams of sodium chloride per liter of water (100 milligrams of chloride per liter). This value is compared with values of 50 to 100 milligrams of chloride per liter found rather commonly now in town wells in eastern Massachusetts. These salt concentrations may be of concern to persons on low-sodium diets and to persons who obtain water from wells in the vicinity of major highways where salt concentrations could be several times higher than average.
Electrical Conductivity and the Red Shift of Absorption in Olivine and Spinel at High Pressure
Authors: Mao H. K. , Bell P. M.
Published: October 2006

Above 100 kilobars the apparent absorption edges (approximately 3 electron volts) of single-crystal and polycrystalline samples of the metastable olivine and stable spinel forms of Fe
2
SiO
4
shift rapidly with pressure from the near-ultraviolet into the lower-energy infrared region. Simultaneously, an exponential increase in electrical conductivity occurs. These effects are reversible as pressure is reduced or reapplied and are not accompanied by a first-order phase change in olivine or spinel. These observations relate to fundamental concepts of electrical conductivity and photon absorption in complex transition-metal silicates in that they cannot be readily interpreted in terms of an intrinsic band-gap model. The intensity and energy changes are too great and the effect occurs at too low a pressure to be explained by processes such as spin-pairing and other crystal-field effects. The results suggest that a new mechanism of conduction, perhaps symbiotic and employing an efficient charge-transfer process, is induced at high pressure.
Chromosomal Proteins in the Dinoflagellate Alga
Gyrodinium cohnii
Authors: Rizzo Peter J. , Noodén Larry D.
Published: October 2006

Chromatin has been prepared from nuclei isolated from the dinoflagellate alga
Gyrodinium cohnii
. This chromatin contains RNA, acid-insoluble proteins, and acid-soluble proteins; the respective ratios to amount of DNA are about 0.09, 0.48, 0.08 (by weight). Not only is the amount of acid-soluble protein associated with the DNA much less than it is in the typical eukaryote, but polyacrylamide gel electrophoresis in urea at
p
H 3.2 produces a banding pattern different from that of typical histones. There is one predominant band that migrates about as fast as does histone IV from corn. These findings are of interest, because the nuclear organization in the dinoflagellates appears to be intermediate between the prokaryotes and the eukaryotes.
Biosynthesis of C4 (Fourth Component of Complement) by Hybrids of C4-Deficient Guinea Pig Cells and HeLa Cells
Authors: Colten Harvey R. , Parkman Robertson
Published: October 2006

Peritoneal exudate cells from guinea pigs homozygous for a genetic deficiency of the fourth component of complement (C4) were fused in vitro with a cell line of human origin (HeLa). The resulting hybrid cells, derived from cell lines each incapable of C4 synthesis by themselves, synthesized functionally active human C4.
1,25-Dihydroxycholecalciferol: Metabolite of Vitamin D
3
Active on Bone in Anephric Rats
Authors: Holick M. F. , Garabedian M. , DeLuca H. F.
Published: October 2006

Nephrectomy prevents completely the bone calcium mobilization response to 25-hydroxycholecalciferol. In contrast it does not prevent this response to 1,25-dihydroxycholecalciferol. Because it is known that the kidney is the site of 1,25-dihydroxycholecalciferol formation, these results provide evidence that 1,25-dihydroxycholecalciferol or a further metabolite thereof and not 25-hydroxycholecalciferol is the metabolically active form of vitamin D
3
responsible for bone calcium mobilization.
Energetics of Foraging: Rate and Efficiency of Nectar Extraction by Hummingbirds
Authors: Wolf Larry L. , Hainsworth F. Reed , Stiles F. Gary
Published: October 2006

The efficiency with which several species of hummingbirds extract nectar was estimated by converting the rate of extraction of nectar volumes to the energy expended and the energy obtained from the nectar. The extraction rates depend on corolla and bill morphologies, and the extraction efficiencies depend, in addition, on the bird weight and nectar concentration. Differential extraction efficiencies can be exploited by plants to increase pollinator specificity.
Asbestos Contamination of Parenteral Drugs
Authors: Nicholson W. J. , Maggiore C. J. , Selikoff I. J.
Published: October 2006

Chrysotile asbestos has been found in approximately one third of the samples from two sets of 17 widely used parenteral drugs.
Vampire Bat Control by Systemic Treatment of Livestock with an Anticoagulant
Authors: Thompson R. Dan , Mitchell G. Clay , Burns Richard J.
Published: October 2006

The blood of beef cattle given single doses (1 milligram per kilogram of body weight) of diphenadione (2-diphenylacetyl-1,3-indandione) became toxic to vampire bats (
Desmodus rotundus
) and remained toxic for 3 days without harming the cattle. Cattle at three ranches in Mexico treated with single intraruminal injections of diphenadione experienced a reduction in vampire bat bites of 93 percent. Bioassays of milk and liver from cattle treated orally with diphenadione in the laboratory indicated that there were no residue problems.
Gas Chromatographic-Mass Spectrometric Assay of Four Indole Alkylamines of Rat Pineal
Authors: Cattabeni F. , Koslow S. H. , Costa E.
Published: October 2006

Gas chromatography-mass spectrometry was used to quantitate serotonin,
N
-acetylserotonin, 5-methoxytryptamine, and melatonin in single rat pineal glands. After gas chromatographic separation, the ion density of specific fragments of each indole was measured with mass spectrometry. Sensitivity of this indole assay is of the order of 10
-12
to 10
-13
mole. Routinely, specificity is based on gas chromatographic retention time and the recording of the ion density generated by specific fragments. Absolute identification of the extracted indoles was based on multiple ion detection.
Chronic Thyroiditis in the Rabbit Induced with Homologous Thyroid Microsomes
Authors: Mangkornkanok Marayart , Markowitz A. S. , Battifora Hector A.
Published: October 2006

Rabbits immunized with freshly isolated homologous thyroid microsomes in complete Freund's adjuvant developed a severe chronic thyroiditis with the concomitant production of antimicrosomal antibodies. The antibody response was measured by indirect immunofluorescence and complement fixation, employing isolated microsomes as the antigen. Microsomes but not thyroglobulin absorbed out the immunologic activity of the rabbit serum.
Brain Serotonin Content: Physiological Regulation by Plasma Neutral Amino Acids
Authors: Fernstrom John D. , Wurtman Richard J.
Published: October 2006

When plasma tryptophan is elevated by the injection of tryptophan or insulin, or by the consumption of carbohydrates, brain tryptophan and serotonin also rise; however, when even larger elevations of plasma tryptophan are produced by the ingestion of protein-containing diets, brain tryptophan and serotonin do not change. The main determinant of brain tryptophan and serotonin concentrations does not appear to be plasma tryptophan alone, but the ratio of this amino acid to other plasma neutral amino acids (that is, tyrosine, phenylalanine, leucine, isoleucine, and valine) that compete with it for uptake into the brain.
Saltbush Leaves: Excision of Hypersaline Tissue by a Kangaroo Rat
Authors: Kenagy G. J.
Published: October 2006

Dipodomys microps
climbs into shrubs and harvests leaves of the halophyte
Atriplex confertifolia
throughout the year. The epidermal vesicles of these leaves are high in electrolyte concentration, but the specialized photosynthetic parenchyma which is arranged concentrically about the vascular bundles is low in electrolytes and high in starch. The lower incisors of
D. microps
are broad, flattened anteriorly, and chisel-shaped (unlike those of other kangaroo rats, which are rounded and awl-shaped) and are used to shave off the hypersaline, peripheral tissue of the leaves so that the inner tissue can be eaten. This atypical feeding behavior should minimize the reliance of
D. microps
on the unpredictable seed crops of desert annuals, and also favor its coexistence with other species of
Dipodomys
, which are primarily granivorous.
Smoke of Cigarettes and Little Cigars: An Analytical Comparison
Authors: Hoffmann Dietrich , Wynder Ernest L.
Published: October 2006

Chemical data are presented from a comparison study of the smoke of cigarettes and little cigars. The tobacco products and their mainstream smokes were analyzed for a number of toxic constituents in an effort to define "smoke inhalability." This issue has particular public health importance because the difference in the inhalability of cigar and cigarette smoke is generally assumed to account for the differences in the health risk to the individual smoker.
Ice and Snow in Eolian Sand Dunes of Southwestern Wyoming
Authors: Steidtmann James R.
Published: October 2006

Snow becomes incorporated in eolian sand dunes of southwestern Wyoming when snow cornices on dune crests begin to melt, slide down the lee slope, and are covered by sand during subsequent lee-slide deposition. In some cases burial is rapid enough to provide the insulation necessary to preserve the ice and snow within the dune throughout the year. Deformed laminae associated with the incorporated snow are preserved, and these features may be of value as paleoclimatic indicators in ancient sandstone.
Juvenile Hormone Mimics: Effect on Cirriped Crustacean Metamorphosis
Authors: Gomez Edgardo D. , Faulkner D. John , Newman William A. , Ireland Chris
Published: October 2006

A synthetic juvenile hormone mimic has been shown to cause premature metamorphosis of the cyprid larva of an acorn barnacle in concentrations as low as 10 parts per billion in filtered seawater. The effect of a juvenile hormone mimic on a crustacean has not previously been demonstrated.
Multilane Vehicular Traffic and Adaptive Human Behavior
Authors: Herman Robert , Lam Tenny , Prigogine Ilya
Published: October 2006

The parameters in a statistical theory of multiple-lane traffic have been determined from two independent sets of data. The numerical values of the parameters calculated by four different methods of estimation are in essential agreement with one another. The data suggest the important role of adaptive human behavior in determining the characteristics of congested flow.
Polar Wandering on Mars?
Authors: Murray Bruce C. , Malin Michael C.
Published: October 2006

Polar wandering during the past 10
8
years may be recorded by unique quasi-circular structures in the polar regions of Mars. Polar wandering on Mars is likely if deep convection is involved in the origin of the very large constructional volcanic features located near the equator. The magnitude of the nonhydrostatic low order components of the gravity field and their correlation with the equatorial volcanic features may be additional evidence of deep convection and associated polar wandering.
Efficiency of Energy Use in the United States
Authors: Hirst Eric , Moyers John C.
Published: October 2006

We described three uses of energy for which greater efficiency is feasible: transportation, space heating, and air conditioning. Shifts to less energy-intensive transportation modes could substantially reduce energy consumption; the magnitude of such savings would, of course, depend on the extent of such shifts and possible load factor changes. The hypothetical transportation scenario described here results in a 22 percent savings in energy for transportation in 1970, a savings of 2800 trillion Btu.

To the homeowner, increasing the amount of building insulation and, in some cases, adding storm windows would reduce energy consumption and provide monetary savings. If all homes in 1970 had the "economic optimum" amount of insulation, energy consumption for residential heating would have been 42 percent less than if the homes were insulated to meet the pre-1971 FHA standards, a savings of 3100 trillion Btu.

Increased utilization of energy-efficient air conditioners and of building insulation would provide significant energy savings and help to reduce peak power demands during the summer. A 67 percent increase in energy efficiency for room air conditioners would have saved 15.8 billion kilowatt-hours in 1970.

In conclusion, it is possible—from an engineering point of view—to effect considerable energy savings in the United States. Increases in the efficiency of energy use would provide desired end results with smaller energy inputs. Such measures will not reduce the
level
of energy consumption, but they could slow energy growth
rates
.
Microorganisms from the Late Precambrian of the Grand Canyon, Arizona
Authors: Schopf J. William , Ford Trevor D. , Breed William J.
Published: October 2006

An assemblage of cellularly well-preserved, filamentous and spheroidal plant microfossils has been detected in a cherty pisolite bed of the late Precambrian Chuar Group from the eastern Grand Canyon of the Colorado River. This newly discovered microflora, probably among the youngest Precambrian biological communities now known, appears to be of both evolutionary and biostratigraphic significance.
Bovine Leukemia Virus Genes in the DNA of Leukemic Cattle
Authors: Callahan Robert , Lieber Michael M. , Todaro George J. , Graves Donald C. , Ferrer Jorge F.
Published: October 2006

Reverse transcripts of the RNA genome of the bovine leukemia virus (BLV) as well as
125
I-labeled BLV RNA hybridize to the DNA of tissues from leukemic cattle with the adult form of the disease but not to bovine thymic lymphoma or normal bovine tissues.
Osmotic Opening of the Blood-Brain Barrier in the Monkey without Associated Neurological Deficits
Authors: Rapoport Stanley I. , Thompson Harry K.
Published: October 2006

Hypertonic urea or lactamide solutions osmotically open the blood-brain barrier in the monkey without producing gross neurological deficits if the blood supply to the brain is not compromised. The brain is perfused via the left lingual artery when the external and common carotid arteries are clamped temporarily. Hypertonic perfusion, which opens the barrier by opening tight junctions between cerebrovascular endothelial cells, can thus be used to study barrier function and brain pharmacology.
Brainstem Neurons Without Spontaneous Unit Discharge
Authors: Siegel Jerome M. , McGinty Dennis J.
Published: October 2006

A new class of single neurons showing no spontaneous activity in waking, rapid eye movement sleep, and slow-wave sleep was found in the brainstem of unrestrained cats. Systematic testing showed that these cells discharge only in response to specific stimuli and remain silent for as long as 40 minutes in the absence of stimulation. Silent cells were widely distributed in the pons and midbrain and constituted a major percentage of observed neurons. The economy of discharge shown by these cells contrasts with the spontaneous activity of virtually all other neurons that have been observed in the brains of unrestrained animals and suggests the widespread existence of specialized neural systems that show only phasic activity.
Specificity of in Vitro Binding of Primate Type C Viral RNA and the Homologous Viral p12 Core Protein
Authors: Sen Arup , Todaro George J.
Published: October 2006

The binding of type C viral p12 proteins to purified viral RNA has been examined in vitro with the use of a family of closely related infectious primate type C viruses—the woolly monkey (SSAV) and gibbon (GALV) group. This in vitro protein-RNA binding is type specific. The system should serve as a model for studies of the evolution of nucleic acid binding proteins.
Oil Spills: Measurements of Their Distributions and Volumes by Multifrequency Microwave Radiometry
Authors: Hollinger J. P. , Mennella R. A.
Published: October 2006

Aircraft-borne multifrequency passive microwave observations of eight marine oil spills revealed that, in all cases, over 90 percent of the oil was confined in a compact region comprising less than 10 percent of the area of the visible slick. These measurements show that microwave radiometry offers a means for measuring the distribution of oil in sea-surface slicks; for locating the thick regions; and for measuring their volumes on an all-weather, day or night, and real-time basis.