bluuebunny/crossref_metadata_2025 huggingface dataset:
Visual Input to the Pontine Nuclei
Authors: Glickstein Mitchell , Stein John , King Richard A.
Published: October 2006

Visual input to the pons was studied by anatomical and physiological methods. Cortical area 18 sends a dense projection to the rostral pons. Pontine cells respond best to targets moving in a preferred direction over a large receptive field, which usually includes the center of gaze. The results suggest a role for pontocerebellar pathways in visual control of movement.
Neurotrophic Effect on Isolated Chick Embryo Muscle in Culture
Authors: Oh T. H. , Johnson D. D. , Kim S. U.
Published: October 2006

Acetylcholinesterase activity in cultures of dissociated skeletal muscle prepared from the thigh muscle of the 10-day-old chick embryo was increased by the presence of innervating spinal cord explants, spinal cord explants in a parabiotic environment, and by media containing brain-spinal cord extract.
Deep-Sea Benthic Community Respiration: An in situ Study at 1850 Meters
Authors: Smith K. L. , Teal J. M.
Published: October 2006

The in situ oxygen uptake of sediments at 1850 meters on the continental slope south of New England is two orders of magnitude less than the uptake of sediments from shallow shelf depths. After treatment of the sediments with Formalin there was no measurable chemical oxygen uptake, which shows that the total uptake is biological (community respiration).
Plant Taxonomy: Ultraviolet Patterns of Flowers Visible as Fluorescent Patterns in Pressed Herbarium Specimens
Authors: Eisner Thomas , Eisner Maria , Hyypio Peter A. , Aneshansley Daniel , Silberglied Robert E.
Published: October 2006

Pressed flowers, in herbarium specimens, show visible fluorescent patterns matching the invisible ultraviolet patterns that the flowers show in life. The technique is taxonomically applicable since it makes an important but usually neglected floral character readily demonstrable.
Bacterial Origin of Sulfuric Acid in Geothermal Habitats
Authors: Mosser Jerry L. , Mosser Anne G. , Brock Thomas D.
Published: October 2006

Natural populations of
Sulfolobus
, a new genus of bacteria occurring in sulfur-rich, acid hot springs and soils, were found to oxidize large amounts of sulfur to sulfuric acid at temperatures up to 85°C. These bacteria are important high-temperature geochemical agents in solfatara soils.
Ion-Exchange in Melanin: An Electron Spin Resonance Study with Lanthanide Probes
Authors: Sarna T. , Hyde James S. , Swartz Harold M.
Published: October 2006

Changes are induced in the electron spin resonance signal amplitude and microwave power saturation of the naturally occurring free radical in melanin by bound paramagnetic ions. The changes serve as experimental observables in competition experiments between diamagnetic and paramagnetic metal ions for melanin binding sites and between melanin and ethylenediaminetetraacetic acid for paramagnetic metal ions. Evidence is presented for the existence of several specific types of metal binding sites. The interaction of copper with free radicals leading to loss of electron spin resonance signal amplitude is magnetic in nature and not, as has been supposed, chemical.
Stimulation of in Vitro Translation of Messenger RNA by Actinomycin D and Cordycepin
Authors: Leinwand Leslie , Ruddle F. H.
Published: October 2006

Actinomycin D and cordycepin were tested for their effect on translation in the wheat germ embryo extract and reticulocyte lysate assays for in vitro protein synthesis. Both drugs were found to stimulate the incorporation of
35
S-labeled methionine into protein up to threefold as compared to control assays. This was true for synthesis directed by murine myeloma polyadenylate-containing RNA, tobacco mosaic virus RNA, and endogenous reticulocyte messenger RNA.
Serotonin Producing Neuroepithelial Bodies in Rabbit Respiratory Mucosa
Authors: Lauweryns Joseph M. , Cokelaere Marnix , Theunynck Paul
Published: October 2006

The intrapulmonary lining epithelium of rabbits contains newly identified corpuscles composed of argyrophil, argentaffin, yellow fluorescent, ultrastructurally granulated and innervated epithelial cellular organs. These are proved, by electron microscopic cytochemistry and microspectrography, to be a source for intrapulmonary production of serotonin. Probably they are intrapulmonary neuroreceptor organs modulated by the central nervous system which exhibit local secretory activities.
Cross-Linking of Collagen
Authors: Tanzer Marvin L.
Published: October 2006

The formation of collagen cross-links is attributable to the presence of two aldehyde-containing amino acids which react with other amino acids in collagen to generate difunctional, trifunctional, and tetrafunctional cross-links. A necessary prerequisite for the development of these cross-links is that the collagen molecules be assembled in the naturally occurring fibrous polymer. Once this condition is met, cross-linking occurs in a spontaneous, progressive fashion. The chemical structures of the cross-links dictate that very precise intermolecular alignments must occur in the collagen polymer. This seems to be a function of each specific collagen because the relative abundance of the different cross-links varies markedly, depending upon the tissue of origin of the collagen.
Regulation of Muscle Acetylcholine Sensitivity by Muscle Activity in Cell Culture
Authors: Cohen Stephen A. , Fischbach Gerald D.
Published: October 2006

Muscle in tissue culture provides a good system for studying long-term changes in surface membrane acetylcholine sensitivity. Muscle fibers stimulated intermittently over prolonged periods are less sensitive to iontophoretically applied acetylcholine and bind less
125
I-labeled α-bungarotoxin than inactive fibers.
Sanfilippo Disease Type B: Enzyme Replacement and Metabolic Correction in Cultured Fibroblasts
Authors: O'Brien J. S. , Miller A. L. , Loverde A. W. , Veath M. L.
Published: October 2006

α-Acetylglucosaminidase, purified from human placenta, corrected the defect in mucopolysaccharide degradation when added to cultured fibroblasts from patients with Sanfilippo disease type B. A small cellular concentration of enzyme gave a large corrective effect. The half-life of disappearance of enzyme activity was 4 to 7 days.
Equipotentiality Quantified: The Anatomical Distribution of the Engram
Authors: Bartlett F. , John E. R.
Published: October 2006

Sensory events and the representation of past experience cause distinctive changes in the electrical activity of widespread regions of the brain. These regions have similar roles in the engram in the sense that they all seem to participate in responses to external events and in subsequent representations of these events. However, the relative contribution of these processes to the activity of different brain regions is quantitatively different, in that some regions are much more strongly affected than others. These results may constitute the basis for reconciliation of localizationist and antilocalizationist views of brain function.
Hurricane Prediction: Progress and Problem Areas
Authors: Simpson R. H.
Published: October 2006

The subjective approach to hurricane prediction of yesteryear has given way to the automation of many facets of prediction, leaving the forecaster with more time to reason dynamically in making the final adjustments to the official track derived from a hierarchy of computer-generated guidances. The most important task immediately ahead is to develop and apply better diagnostic procedures to help the forecaster identify the guidance sources which are most likely to contain the truth, and to help assure that his final decision will either succeed or fail safely.

The ultimate prediction method for both hurricane development and movement will probably need to simulate not only the circulation of the hurricane but the interaction of the cloud clusters in its vortex with the large-scale environment. Assuming that this can be effectively done, the most important further handicap will be the problem of describing the initial conditions.

The development of a model which will dependably simulate the behavior of the three hurricanes in ten that turn out to be bad actors will not likely become operational in the near future. The most troubling problem in applying such a model—and it would have to be tested for years over a range of many storm types and conditions before becoming fully operational—is that the more complex the model is the more inscrutable the results are and the more difficult it becomes to identify the condition in which computational failure is probable. It would appear, therefore, that engineering approaches to prediction and diagnostic procedures of evaluation will dominate the methodology of hurricane forecasting for a number of years to come.
Gravitational Evidence for a Low-Density Mass beneath the Galápagos Islands
Authors: Case J. E. , Ryland S. L. , Simkin Tom , Howard K. A.
Published: October 2006

A residual negative free-air and Bouguer anomaly of at least 80 milligals, superimposed on a broader high, occurs over the Galápagos Islands. The axis of the anomaly trends roughly east and plunges eastward. Thus, a low-density mass in the crust or upper mantle must underlie the archipelago. This anomaly may be caused by thermal expansion over a crust-mantle "hot spot".
Deep-Sea Species Diversity: Decreased Gastropod Diversity at Abyssal Depths
Authors: Rex Michael A.
Published: October 2006

Gastropod species diversity is low on the continental shelf, high on the continental slope and abyssal rise, and then decreases with increasing distance out onto the abyssal plain. Increased diversity below the continental shelf has been attributed to increased environmental stability. Decreased diversity on the abyss may result from extremely low productivity.
Two Visual Systems in the Frog
Authors: Ingle David
Published: October 2006

After unilateral removal of the optic tectum in frogs, the cut optic tract regenerates to the remaining ipsilateral tectum. Although the orienting movements elicited by moving objects (food or threats) are now directed mirror-symmetrically to normal responses, these frogs correctly localize stationary objects as barriers. Apparently, thalamic and tectal visual mechanisms can operate independently.
Enhanced Protein Adsorption at the Solid-Solution Interface: Dependence on Surface Charge
Authors: Mattson James S. , Smith Carroll A.
Published: October 2006

By the use of infrared internal reflection spectroelectrochemistry, it has been possible to observe an enhanced adsorption of porcine fibrinogen onto a germanium surface at potentials more positive than —200 millivolts relative to a saturated calomel electrode. The enhanced adsorption was observed directly at the interface between the solid and the aqueous solution.
Curvature as a Feature of Pattern Vision
Authors: Riggs Lorrin A.
Published: October 2006

Prolonged inspection of convex lines of one color and concave lines of another color can cause the appearance of oppositely colored aftereffects in curved, achromatic test lines. These effects, strongly dependent on radius of curvature, cannot be attributed to tilt or orientation. It is concluded that these results are not encompassed by models of the visual system that are based on rectilinear arrays and that curvature is a specific feature of human visual perception.
Chondrites: Initial Strontium-87/Strontium-86 Ratios and the Early History of the Solar System
Authors: Wetherill G. W. , Mark R. , Lee-Hu C.
Published: October 2006

A sodium-poor, calcium-rich inclusion in the carbonaceous chondrite Allende had a
87
Sr/
86
Sr ratio at the time of its formation of 0.69880, as low a value as that found in any other meteorite. The higher
87
Sr/
86
Sr ratios found in ordinary chondrites indicate that their formation or isotopic equilibration occurred tens of millions of years later.
Lead Metabolism in the Normal Human: Stable Isotope Studies
Authors: Rabinowitz Michael B. , Wetherill George W. , Kopple Joel D.
Published: October 2006

Kinetic and metabolic balance studies in a healthy man fed a diet normal in lead content and labeled with lead-204 indicated that approximately two-thirds of his assimilated lead was dietary in origin; the remainder was inhaled. Kinetic analysis shows that the isotopic data can be interpreted by a three-compartment model.
Phonotaxis of Crickets in Flight: Attraction of Male and Female Crickets to Male Calling Songs
Authors: Ulagaraj S. M. , Walker Thomas J.
Published: October 2006

Large numbers of two species of mole crickets flew to loudspeakers playing the appropriate calling song outdoors. Mated females were more frequently captured than unmated ones, and males were 12 percent of the catch. Crickets of three other subfamilies were trapped as they flew to mole cricket songs resembling their own.
Jupiter's Great Red Spot: A Free Atmospheric Vortex?
Authors: Ingersoll Andrew P.
Published: October 2006

A simple hydrodynamic model yields steady-state solutions with many of the properties of the Great Red Spot and the neighboring belts and zones of Jupiter. No special forcing mechanism is necessary to maintain the circulation of the Spot. This is consistent with observations which indicate that the Great Red Spot and the zones have similar dynamic properties.
Ability of the c-
mos
Product to Associate with and Phosphorylate Tubulin
Authors: Zhou Renping , Oskarsson MarianneRichard S.z , Paules Richard S. , Schulz Nicholas , Cleveland Don , Vande Woude George F
Published: October 2006

The
mos
proto-oncogene product, pp39

mos

, is a protein kinase and has been equated with cytostatic factor (CSF), an activity in unfertilized eggs that is thought to be responsible for the arrest of meiosis at metaphase II. The biochemical properties and potential substrates of pp39

mos

were examined in unfertilized eggs and in transformed cells in order to study how the protein functions both as CSF and in transformation. The pp39

mos

protein associated with polymers under conditions that favor tubulin oligomerization and was present in an approximately 500-kilodalton "core" complex under conditions that favor depolymerization. β-Tubulin was preferentially coprecipitated in pp39

mos

immunoprecipitates and was the major phosphorylated product in a pp39

mos

-dependent immune complex kinase assay. Immunofluorescence analysis of NIH 3T3 cells transformed with
Xenopus
c-
mos
showed that pp39

mos

colocalizes with tubulin in the spindle during metaphase and in the midbody and asters during telophase. Disruption of microtubules with nocodazole affected tubulin and pp39

mos

organization in the same way. It therefore appears that pp39

mos

is a tubulin-associated protein kinase and may thus participate in the modification of microtubules and contribute to the formation of the spindle. This activity expressed during interphase in somatic cells may be responsible for the transforming activity of pp39

mos

.
Artificial Vision for the Blind: Electrical Stimulation of Visual Cortex Offers Hope for a Functional Prosthesis
Authors: Dobelle W. H. , Mladejovsky M. G. , Girvin J. P.
Published: October 2006

Electrical stimulation of the occipital cortex resulted in discrete photic sensations or "phosphenes" in two volunteers who had been totally blind for 7 and 28 years, respectively. Stimulation of multiple electrodes allowed one patient to recognize simple patterns, including letters. Both patients made an uneventful recovery, and the success of these experiments reinforces the hope that a functional visual prosthesis can be developed, although many problems remain to be solved.
Torpor in an Andean Hummingbird: Its Ecological Significance
Authors: Carpenter F. Lynn
Published: October 2006

Field studies on an Andean hummingbird showed that nocturnal torpor occurs more frequently and lasts longer in the winter. Energy depletion does not seem to cause this yearly torpor cycle, and a photoperiodically controlled rhythm that enables the birds to automatically conserve energy in early evening for possible metabolic expenditures required later in the winter night is suggested.
Female Steroid Hormones and Target Cell Nuclei
Authors: O'Malley Bert W. , Means Anthony R.
Published: October 2006

The data discussed herein demonstrate the great variation in target-tissue response that can occur after administration of steroid hormones. The female sex steroids can exert regulatory effects on the synthesis, activity, and possibly even the degradation of tissue enzymes and structural proteins. Each response, nevertheless, appears to be dependent on the synthesis of nuclear RNA. In many instances, the steroid actually promotes a qualitative change in the base composition and sequence of the RNA synthesized by the target cell, implying a specific effect on gene transcription. Most important is our direct quantitative evidence that sex steroids cause a net increase in the intracellular amounts of specific mRNA molecules in target tissues.

It thus appears that we are discovering a pattern of steroid hormone action which includes: (i) uptake of the hormone by the target cell and binding to a specific cytoplasmic receptor protein; (ii) transport of the steroid-receptor complex to the nucleus; (iii) binding of this "active" complex to specific "acceptor" sites on the genome (chromatin DNA and acidic protein); (iv) activation of the transcriptional apparatus resulting in the appearance of new RNA species which includes specific mRNA's; (v) transport of the hormone-induced RNA to the cytoplasm resulting in synthesis of new proteins on cytoplasmic ribosomes; and (vi) the occurrence of the specific steroid-mediated "functional response" characteristic of that particular target tissue.

To elucidate fully the mechanism of steroid hormone action we must study the biochemistry of the process by which information held by the steroid hormone-receptor complex is transferred to the nuclear transcription apparatus. If our assumptions are correct, we should ultimately be able to discover how this hormone-receptor complex exerts a specific regulatory effect on nuclear RNA metabolism. Such regulation might be achieved (i) by direct effects on chromatin template leading to increased gene transcription and thus RNA synthesis; (ii) by activation of the polymerase complex itself; (iii) by inhibition of RNA breakdown; or (iv) by intranuclear processing of large precursor molecules so that smaller biologically active sequences are produced, and (v) by transport of RNA from the nucleus to the cytoplasmic sites of cellular protein synthesis.
Brain Hyaluronidase: Changes in Activity during Chick Development
Authors: Polansky Jon R. , Toole Bryan P. , Gross Jerome
Published: October 2006

Development of embryonic chick brain is characterized by high levels of hyaluronidase activity and of hyaluronate, both of which decrease rapidly soon after the chick hatches. By analogy to other systems, it is proposed that the sequence of hyaluronate production and its enzymatic removal may have a developmental role in brain formation.
Eustatic Sea Level 120,000 Years Ago on Oahu, Hawaii
Authors: Ku Teh-Lung , Kimmel Margaret A. , Easton William H. , O'Neil Thomas J.
Published: October 2006

Extensive dating of the fossil corals associated with the Waimanalo shoreline on Oahu has shown that 120,000 years ago the ocean was approximately 7.6 meters above its present level. Corals grown during that time constitute a major portion of the subaerial reef-derived material on the island, with exposures ranging from about 10 meters to near sea level. This evidence corroborates the notion that 120,000 years before the present was the last time during which the sea stood significantly higher than it does today. The reported benches at 3.7, 1.5, and 0.6 meters, if not of Recent origin, could be features created by brief halts of the sea during rapid regression shortly after the Waimanalo high stand.
Fate of α-Bungarotoxin Bound to Acetylcholine Receptors of Normal and Denervated Muscle
Authors: Berg Darwin K. , Hall Zach W.
Published: October 2006

In organ culture, α-[
125
I]bungarotoxin bound to extrajunctional receptors of denervated muscle is lost from the tissue at a more rapid rate than the toxin bound to the junctional receptors of normal muscle. The rapid loss of toxin from denervated muscle can be blocked by inhibitors of energy production and protein synthesis, and may reflect turnover of the toxin-receptor complex in the membrane.
Air Pollution: Remote Detection of Several Pollutant Gases with a Laser Heterodyne Radiometer
Authors: Menzies R. T. , Shumate M. S.
Published: October 2006

An infrared heterodyne radiometer with a spectral resolution of 0.04 reciprocal centimeters has been used to remotely detect samples of ozone, sulfur dioxide, ammonia, and ethylene at room temperature, and samples of nitric oxide at 390K. Each gas was observed in a background of nitrogen or oxygen at atmospheric pressure. Sensitivities to some of these gases are adequate for detection of ambient concentrations as low as a few parts per billion.
Carnosine in the Primary Olfactory Pathway
Authors: Margolis Frank L.
Published: October 2006

Carnosine (β-alanyl-L-histidine) is present in mouse olfactory bulbs and nasal olfactory epithelium at concentrations exceeding that previously reported for any brain region of any species. After peripheral deafferentation, carnosine concentrations in the olfactory bulbs decrease to less than 10 percent that of normal, while other amino compounds are unaffected. Carnosine appears to be highly localized to the primary olfactory pathway.
Spectroscopic Measurements of Stratospheric Nitric Oxide and Water Vapor
Authors: Patel C. K. N. , Burkhardt E. G. , Lambert C. A.
Published: October 2006

Spectroscopic measurements have been made of the nitric oxide and water vapor concentrations in the stratosphere at an altitude of 28 kilometers. The measurements, carried out in situ with the use of a spin flip Raman laser, represent the first accurate determination of nitric oxide as a function of time (as the sun rose) from about 6: 30 to 14:00 C.D.T.
Lateral Phase Separation of Lipids in Plasma Membranes: Effect of Temperature on the Mobility of Membrane Antigens
Authors: Petit Valerie A. , Edidin Michael
Published: October 2006

Cooling populations of newly formed mouse human heterokaryons has effects on the intermixing of mouse and human surface antigens which indicate the occurrence of phase separations in membrane lipids. Antigen mixing, previously shown to be due to diffusion in the plane of the membrane, is retarded when cells are cooled from 37° to 21°C, but is then speeded by further cooling to 15°C. This result is in accord with observations on phase separations of lipids in artificial and bacterial membranes.
Growth Hormone Responses to Melatonin in Man
Authors: Smythe G. A. , Lazarus L.
Published: October 2006

Oral administration of 1 gram of melatonin caused rapid and significant elevations of serum human growth hormone in eight out of nine normal male subjects. The mean (± standard error of the mean) of the peak response by growth hormone was 22.9 ± 4.6 microunits per milliliter. The increased secretion of growth hormone may be due to interaction of melatonin with hypothalamic serotoninergic receptors.
Probable Fijian Origin of Quartzose Temper Sands in Prehistoric Pottery from Tonga and the Marquesas
Authors: Dickinson William R. , Shutler Richard
Published: October 2006

Quartzose temper sands included within fired clay bodies of certain prehistoric potsherds from Tonga and the Marquesas have mineralogical compositions wholly different from those of indigenous sands that occur as temper in other potsherds from the same sites but are indistinguishable from sands in potsherds collected from the Rewa Delta of Viti Levu in Fiji.
Sex Pheromones and Reproductive Isolation of the Lesser Peachtree Borer and the Peachtree Borer
Authors: Tumlinson J. H. , Yonce C. E. , Doolittle R. E. , Heath R. R. , Gentry C. R. , Mitchell E. R.
Published: October 2006

(
E,Z
)-3,13-octadecadien-1-ol acetate, and (
Z,Z
)-3,13-octadecadien-1-ol acetate, isolated from the female lesser peachtree borer,
Synanthedon pictipes
(Grote and Robinson), and the female peachtree borer,
Sanninoidea exitiosa
(Say), respectively, strongly attract the respective males of these species in field bioassays. These compounds are the largest pheromones isolated thus far from a lepidopterous species.
Sanninoidea exitiosa
males did not respond to the synthesized (
E,Z
)-isomer, and low concentrations of it in the synthesized (
Z,Z
)-isomer did not interfere with their response to the (
Z,Z
)-isomer. In contrast, even very low concentrations of the (
Z,Z
)-isomer (1 percent) in the (
E,Z
)-isomer significantly inhibited the response of
Synanthedon pictipes
males.
Mitogenic Activity of Sterculic Acid, a Cyclopropenoid Fatty Acid
Authors: Scarpelli D. G.
Published: October 2006

Hepatocytes in rainbow trout and rat are stimulated to augmented DNA synthesis and cell division by low concentrations of cyclopropenoid fatty acids in the diet. Sterculic acid isolated as the methyl ester from
Sterculia foetida
oil has been identified as one of the mitogenic principles.
Earthquake Prediction: Absence of a Precursive Change in Seismic Velocities before a Tremor of Magnitude 3¾
Authors: McGarr A.
Published: October 2006

P
-wave velocities in the region near the source of a tremor of magnitude 3¾ were constant to within 2 percent for 41 days before the event; no evidence of a precursive change in velocity was found. Observations of
S
-wave velocities and the ratio of
P
-wave to
S
-wave velocities also showed no precursive changes. In recent studies, premonitory changes in body-wave velocities of about 10 percent and having a duration of 2 to 3 weeks have been reported for crustal earthquakes of this size.
Puromycin: A Questionable Drug for Studying the Mechanism of Thyroid Calorigenesis in vivo
Authors: Bilder Glenda E. , Denckla W. Donner
Published: October 2006

Puromycin fails to alter minimal oxygen consumption of rats treated with thyroxine, provided the rectal temperatures of these rats are maintained at 37.8° to 38.1°C. The previously reported puromycin-induced decline in basal metabolic rate of thyroxine-treated rats may have been due to the hypothermia produced by this drug.
Lymphocytic Choriomeningitis in a Hamster Colony Causes Infection of Hospital Personnel
Authors: Hotchin John , Sikora Edward , Kinch William , Hinman Alan , Woodall John
Published: October 2006

A series of febrile illnesses, some severe, among hospital personnel was traced to an outbreak of lymphocytic choriomeningitis in a hospital research colony of Syrian hamsters. By rapid virus isolation and identification techniques, a definitive diagnosis was made 5 days after specimens were received. This outbreak emphasizes the dangers of working with experimental hamsters and tumor cell lines passaged in them.
Computerized Transaxial X-ray Tomography of the Human Body
Authors: Ledley R. S. , Di Chiro G. , Luessenhop A. J. , Twigg H. L.
Published: October 2006

The ACTA-Scanner has virtually unlimited potential in the evaluation of any part of the body. The usefulness of the technique has already been shown in the appraisal of pathologies of the brain and cerebrospinal fluid cavities. The orbits and the eyeballs, the facial sinuses, and skull base lesions have also been elucidated.

Tumors of the larynx, pharynx, thyroid, and parathyroid; lymphomas; and pathology of the spine and spinal cord are well within the reach of this new diagnostic methodology. Lung pathologies, such as emphysema, pneumonias, neoplasms, infarctions, pleural effusions and granulomatous diseases, and mediastinal pathology represent a challenging complex of lesions to be appraised by ACTA-scanning. For the heart, there is great potential for observing cardiac chamber size, hypertrophy of ventricular or atrial walls, and ventricular or aortic aneurysms, and possibly for recognizing the damaged myocardial tissue immediately after or some time after an infarction. The abdominal pathologies that can be studied are almost uncountable: gastric neoplasms, pancreatic cysts and stones, gallstones, neoplasms of the liver and pancreas, bowel tumors, abdominal aortic aneurysms, renal neoplasms and cysts, atrophy of the kidneys, bladder tumors, uterine tumors, ovarian cysts, and many more. Although bones and joints are adequately demonstrated by conventional x-ray techniques, there is no doubt that as the new technique is developed ACTA-grams will contribute significant information in the transverse plane, as well as in densitometric analyses.

The impact of ACTA-scanning will not be limited to the diagnostic area, but will extend, at least indirectly, to general patient management and to some aspects of medical economics as well. Risk-laden, technically complex, and costly diagnostic procedures, sometimes requiring lengthy hospitalization, will in some cases be eliminated. The simple, innocuous, and noninvasive ACTA-scanning can be performed on an outpatient basis. Repeated follow-up examinations should be easily accepted by the patients, considering that this diagnostic test is carried out without discomfort. The entire field of diagnostic radiology is on the verge of revolutionary changes.
Singlet Excited Oxygen as a Mediator of the Antibacterial Action of Leukocytes
Authors: Krinsky Norman I.
Published: October 2006

Human polymorphonuclear leukocytes kill a colorless mutant strain of
Sarcina lutea
much more readily than a carotenoid-containing strain. A similar protective effect has been reported in the organism during photodynamic inactivation, where it is attributable to the quenching of singlet excited oxygen by carotenoids. The findings with leukocytes support the suggestion that singlet excited oxygen acts as one of the mediators of their bactericidal action.
Aerosol and Climate: Some Further Considerations
Authors: Weare Bryan C. , Temkin Richard L. , Snell Fred M.
Published: October 2006

Approximate numerical radiative calculations show that whether added aerosol causes heating or cooling of the earth-atmosphere system is a function not only of its intrinsic absorption-backscatter characteristics but also of its particular location in the atmosphere with respect to the average cloud as well as of both the cloud reflectivity and the underlying surface reflectivity.
1α-Hydroxyvitamin D
2
: A Potent Synthetic Analog of Vitamin D
2
Authors: Peter Lam H. -Y. , Schnoes H. K. , DeLuca H. F.
Published: October 2006

A hydroxy analog of vitamin D
2
, 1α-hydroxyvitamin D
2
, has been synthesized and tested for biological activity. This vitamin derivative is active in stimulating intestinal calcium transport and bone calcium mobilization in the rat and exhibits antirachitic activity. Its biopotency is comparable to that of the corresponding vitamin D
3
analog, 1α-hydroxyvitamin D
3
.
Decrease in Free Cystine Content of Cultured Cystinotic Fibroblasts by Ascorbic Acid
Authors: Kroll Wolfgang A. , Schneider Jerry A.
Published: October 2006

The 100-fold increase in free cystine content characteristic of cultured skin fibroblasts from patients with nephropathic cystinosis was decreased more than 50 percent by addition of L-ascorbic acid to the culture medium at concentrations of 0.29 to 2.9 millimolar. Fresh ascorbic acid must be added to the culture medium daily to produce a progressive decrease of the free cystine content of the cells over a 3-day period. Upon removal of ascorbic acid from the medium, the free cystine content returns to its initial value.
Photochemical Reactions as a Tool in Organic Syntheses
Authors: Turro Nicholas J. , Schuster Gary
Published: October 2006

This article represents only a brief glimpse into one of the fascinating aspects of the chemistry of electronically excited molecules. More exhaustive coverage of synthetic applications of photochemical reactions may be found in texts and reviews. We summarize here by noting that classification of reliable photoreactions is possible, but that the most effective application of the classification scheme requires a familiarity with some of the special features of the chemistry of electronically excited states. Thus, knowledge of the properties of singlet and triplet states, the factors which determine photochemical efficiency and reactivity, and the special technical aspects of photochemical procedures such as selective direct and photosensitized excitation and photoexcitation at low temperatures or solid matrices make photochemistry a useful tool for the construction of organic molecules. It is our hope that the material and flavor of this article will whet the intellectual and experimental appetites of researchers who are concerned with various aspects of the synthesis of organic molecules.
Primitively Columellaless Pollen: A New Concept in the Evolutionary Morphology of Angiosperms
Authors: Walker James W. , Skvarla John J.
Published: October 2006

Comparative study of pollen of the ranalean complex has revealed a remarkable, hitherto unrecognized characteristic of primitive angiosperm pollen, namely, its complete lack of columellae. Pollen with such exine has been designated
atectate
and taxa in the Magnoliaceae, Degeneriaceae, Eupomatiaceae, Annonaceae, and possibly Himantandraceae and Nymphaeaceae have pollen which is considered to be primitively columellaless.
Earthquake Prediction: Modeling the Anomalous V
p
/V
s
Source Region
Authors: Griggs David T. , Jackson David D. , Knopoff Leon , Shreve Ronald L.
Published: October 2006

Soviet observations of anomalously low values of the ratio of the compressional wave velocity to the shear wave velocity (
V
P
/
V
S
) in a restricted volume around the locus of a future earthquake are duplicated by models based on the dilatancy hypothesis. In nature the cracks that cause the dilation may be oriented, leading to anisotropic seismic wave propagation in the anomalous region. The models show that vertical cracks are most effective in producing the observed effects, but that a slightly higher density of randomly oriented cracks will yield similar effects. The premonitory observations at Blue Mountain Lake, New York, are also duplicated by the models. These models demonstrate that
V
P
/
V
S
measured at the surface is not that of the anomalous zone, but is related to it by a transfer function, involving the shape and velocity gradient of the zone boundary.
Permanent Translocation Heterozygosity and Sex Determination in East African Mistletoes
Authors: Wiens Delbert , Barlow Bryan A.
Published: October 2006

Viscum fischeri
has 2
n
= 23 chromosomes in male plants. These form 7 bivalents and a translocation chain of 9 chromosomes during meiosis. Pollen with 11- and 12-chromosome genomes is thus produced. Female plants have 2
n
= 22 chromosomes and produce 11 bivalents during meiosis. Sex determination is technically a rare multiple X-multiple Y type, but more importantly it provides the mechanism whereby permanent translocation heterozygosity is maintained in the system. In a second species,
Viscum engleri
, male plants have 2
n
= 28 chromosomes, associating as 11 bivalents and a ring of 6 chromosomes at meiosis.
Submarine Barite-Opal Rocks of Hydrothermal Origin
Authors: Bertine K. K. , Keene J. B.
Published: October 2006

Unusual submarine rocks consisting of barite, opal, and volcanic detritus were recovered from the Lau Basin northeast of Australia. It is proposed that these rocks were formed when hydrothermal solutions emanating from a fracture zone offsetting the active spreading center in the Lau Basin came into contact with cooler ocean waters.
Stratospheric Dust-Aerosol Event of November 1974
Authors: Meinel Aden B. , Meinel Marjorie P.
Published: October 2006

A strong incursion of dust and aerosol at an altitude of 20 kilometers was noted over Baja California and southern Arizona in mid-November 1974, as indicated by bluish-ashen daylight skies and colorful twilight glows of the type usually associated with volcanic eruptions. Infrared satellite observations and reports from other sources eliminated a possible oceanic origin in the eastern Pacific. The stratum is probably from the extensive eruption of Volcan de Fuego in Gautemala in October 1974.
Analysis of Living Tissue by Phosphorus-31 Magnetic Resonance
Authors: Burt C. Tyler , Glonek Thomas , Bárány Michael
Published: October 2006

Nuclear magnetic resonance is a new method for assaying the content of phosphate metabolites in intact tissues. Its nondestructive nature allows simultaneous and repeated determinations of these compounds with a minimum perturbation of tissue. Changes in the concentrations of the phosphates as a function of time characterize the metabolic machinery of the tissue and reveal alterations in enzymic activity that result from drug treatment or disease.

The entire phosphate profile shows differences between normal and diseased muscle which should be of diagnostic value. Further, by examining phosphate profiles we detected a family of chemical compounds that were not previously known to exist as major constituents in muscle. Of these, two have been isolated and one has been identified as glycerol 3-phosphorylcholine.

Finally, shifts in the positions of resonances monitor the internal environment of the living system, its hydrogen ion concentration, the complexing of alkaline earth metals with ATP, and compartmentalization within the cell.
Droplet Chondrules
Authors: Kieffer Susan Werner
Published: October 2006

I have proposed that droplet chondrules were formed by jetting during collision of meteoritic particles with diameters ranging in order of magnitude from 0.5 mm to 20 cm. This conclusion, based on a dynamic model for the collision process, supports the hypotheses of Wasson (based on geochemical considerations) and Whipple and Cameron (based on dynamic model considerations) that chondrules were formed from objects less than 1 m in radius.

In this model, the formation of chondrules is viewed as a textural, but not substantial chemical, change in the material of the early solar system. Droplets of melt produced by jetting are mixtures of material derived from two parent grains. Jets are probably not appreciably fractionated (except in volatile elements) either in the short duration of the shock events (several microseconds) or in subsequent cooling.

This model for the formation of droplet chondrules implies that they were formed at a time in the history of the solar system when particle sizes were small. The most likely time for this condition is early in the process of accretion of nebular dust to planetary matter. Since velocities less than approximately 1.5 km/sec are required for the agglomeration and accretion of particles, the relatively higher velocities indicated for droplet chondrule-forming collisions indicate an early high-velocity destructive epoch amidst the general trend toward accretion of material.
Oxygen and Carbon Isotopes from Calcareous Nannofossils as Paleoceanographic Indicators
Authors: Margolis Stanley V. , Kroopnick Peter M. , Goodney David E. , Dudley Walter C. , Mahoney Maureen E.
Published: October 2006

Oxygen-18 and carbon-13 analyses of well-preserved calcareous nannofossils have been compared with those of foraminifera contained in Cenozoic cores collected in the Southern Ocean during the Deep Sea Drilling Project. The results indicate that calcareous nannofossils deposit calcium carbonate at or near equilibrium with oceanic surface waters and that they can be used as paleotemperature indicators.
Cyclic Octatomic Sulfur: A Possible Infrared and Visible Chromophore in the Clouds of Jupiter
Authors: Khare B. N. , Sagan Carl
Published: October 2006

A brown polymeric material, produced under simulated Jovian conditions, is composed primarily of cyclic octatomic sulfur, although a range of complex organic compounds is also present. The polymeric sulfur, produced from the ultraviolet photolysis of hydrogen sulfide, exhibits its strongest band at 465 reciprocal centimeters, in fair agreement with the frequency of the unidentified Jovian absorber recently announced by Houck
et al.
Polymeric octatomic sulfur may be an important constituent of the Jovian clouds.
Molecular Transfer of a Species-specific Behavior from
Drosophila simulans
to
Drosophila melanogaster
Authors: Wheeler David A. , Kyriacou Charalambos P. , Greenacre Mary L. , Yu Qiang , Rutila Joan E. , Rosbash Michael , Hall Jeffrey C.
Published: October 2006

Drosophila
males modulate the interpulse intervals produced during their courtship songs. These song cycles, which are altered by mutations in the clock gene
period
, exhibit a species-specific variation that facilitates mating. We have used chimeric
period
gene constructs from
Drosophila melanogaster
and
Drosophila simulans
in germline transformation experiments to map the genetic control of their song rhythm difference to a small segment of the amino acid encoding information within this gene.
Induction of Self-Rolerance in T Cells But Not B Cells of Transgenic Mice Expressing Little Self Antigen
Authors: Adelstein Stephen , Pritchard-Briscoe Helen , Anderson Tracy A. , Crosbie Jeffrey , Gammon Guy , Loblay Robert H. , Basten Antony , Goodnow Christopher C.
Published: October 2006

Self-tolerance to a transgene-encoded protein, hen egg lysozyme, was examined in the T and B cell repertoires of a series of lines of transgenic mice that expressed different serum concentrations of soluble lysozyme. T cells were tolerant in all lines in which lysozyme was expressed irrespective of the antigen concentration, whereas B cell tolerance did not occur when the serum lysozyme concentration was less than 1.5 nanograms per milliliter (0.1 nM). Induction of elevated transgene expression could restore B cell tolerance. These findings support the hypothesis that autoimmune disease may in some instances arise through a bypass of T cell tolerance.
Network Rigidity and Metabolic Engineering in Metabolite Overproduction
Authors: Stephanopoulos Gregory , Vallino Joseph J.
Published: October 2006

In order to enhance the yield and productivity of metabolite production, researchers have focused almost exclusively on enzyme amplification or other modifications of the product pathway. However, overproduction of many metabolites requires significant redirection of flux distributions in the primary metabolism, which may not readily occur following product deregulation because metabolic pathways have evolved to exhibit control architectures that resist flux alterations at branch points. This problem can be addressed through the use of some general concepts of metabolic rigidity, which include a means for identifying and removing rigid branch points within an experimental framework.
Dimerization of Human Growth Hormone by Zinc
Authors: Cunningham Brian C. , Mulkerrin Michael G. , Wells James A.
Published: October 2006

Size-exclusion chromatography and sedimentation equilibrium studies demonstrated that zinc ion (Zn
2+
) induced the dimerization of human growth hormone (hGH). Scatchard analysis of
65
Zn
2+
binding to hGH showed that two Zn
2+
ions associate per dimer of hGH in a cooperative fashion. Cobalt (II) can substitute for Zn
2+
in the hormone dimer and gives a visible spectrum characteristic of cobalt coordinated in a tetrahedral fashion by oxygen- and nitrogen-containing ligands. Replacement of potential Zn
2+
ligands (His
18
, His
21
, and Glu
174
) in hGH with alanine weakened both Zn
2+
binding and hGH dimer formation. The Zn
2+
-hGH dimer was more stable than monomeric hGH to denaturation in guanidine-HCl. Formation of a Zn
2+
-hGH dimeric complex may be important for storage of hGH in secretory granules.
Reproductive Development in a Female Songbird: Differential Stimulation by Quality of Male Song
Authors: Kroodsma Donald E.
Published: October 2006

Female canaries exposed to playback of large repertoires of male songs built nests faster and laid more eggs than did those females exposed to smaller song repertoires: females are attentive to attributes of male song, and their choices have played a role in the evolution of oscine singing behaviors.
Controls on the Preservation of Biogenic Opal in Sediments of the Eastern Tropical Pacific
Authors: Johnson Thomas C.
Published: October 2006

A map of the preservation pattern of siliceous microfossils was constructed from an examination of 125 piston and gravity cores of Quaternary sediments from throughout the eastern tropical Pacific. Preservation is enhanced where high surface water productivity supplies a high input rate of siliceous tests to the sea floor, except in a large area north of 5°N, east of the East Pacific Rise. Here a high input rate of terrigenous silicates may adversely affect preservation of biogenic opal in the sea-floor sediments.
Meteoroid Storms Detected on the Moon
Authors: Duennebier F. K. , Nakamura Y. , Latham G. V. , Dorman H. J.
Published: October 2006

Seismometers on the moon have detected several brief periods of enhanced meteoroid-impact activity, believed to represent encounters of the moon with "clouds" of objects in the kilogram range. The latest and most active encounter, in June 1975, is interpreted as a meteoroid cloud of diameter 0.1 astronomical unit and total mass 10
13
to 10
14
grams.
Establishment of the Mesoderm-Neuroectoderm Boundary in the
Drosophila
Embryo
Authors: Kosman David , Ip Y. Tony , Levine Michael , Arora Kavita
Published: October 2006

A gradient of the maternal morphogen
dorsal
establishes asymmetric patterns of gene expression along the dorsal-ventral axis of early embryos and activates the regulatory genes
twist
and
snail
, which are responsible for the differentiation of the ventral mesoderm. Expression of
snail
is restricted to the presumptive mesoderm, and the sharp lateral limits of this expression help to define the mesoderm-neuroectoderm boundary by repressing the expression of regulatory genes that are responsible for the differentiation of the neuroectoderm. The
snail
gene encodes a zinc finger protein, and neuroectodermal genes that are normally restricted to ventral-lateral regions of early embryos are expressed throughout ventral regions of
snail
-
mutants. The formation of the sharp
snail
border involves dosage-sensitive interactions between
dorsal
and
twist
, which encode regulatory proteins that are related to the mammalian transcription factors NF-kB and MyoD, respectively.
A mutation in the Amyloid Precursor Protein Associated with Hereditary Alzheimer's Disease
Authors: Murrell Jill , Farlow Martin , Ghetti Bernardino , Benson Merrill D.
Published: October 2006

Alzheimer's disease is a form of localized amyloidosis characterized by cerebral cortical amyloid plaques, neurofibrillary tangles, and amyloid deposits within the walls of leptomeningeal vessels. Although most cases of Alzheimer's disease are sporadic, kindreds with autosomal-dominant inheritance of the syndrome suggest that a single mutation may be important in pathogenesis. Direct sequencing of DNA from a family with autopsy-proven Alzheimer's disease revealed a single amino acid substitution (Phe for Val) in the transmembrane domain of the amyloid precursor protein. This mutation correlates with the presence of Alzheimer's disease in all patients in this study, and may be the inherited factor causing both amyloid fibril formation and dementia.
Migration Reversal: A Regular Phenomenon of Canada Geese
Authors: Raveling Dennis G.
Published: October 2006

Migration from a nesting to a wintering ground and back again in autumn was detected each year during a 3-year study of individually identifiable Canada geese (
Branta canadensis
). Reverse migrants were primarily yearling, nonbreeding individuals and others of nonfamily status.
Fog Catchment Sand Trenches Constructed by Tenebrionid Beetles,
Lepidochora
, from the Namib Desert
Authors: Seely Mary K. , Hamilton William J.
Published: October 2006

Three species of coastal Namib Desert tenebrionid beetles (
Lepidochora
) build trenches on desert sand dunes. Trenches are constructed perpendicular to fog winds and concentrate moisture during fogs. The beetles return along the ridges of the trenches extracting water from them. The water content of a population of these beetles increased by 13.9 percent during one fog.