bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictions of formant-frequency discrimination in noise based on model auditory-nerve responses
Authors: Tan Qing , Carney Laurel H.
Published: September 2006

To better understand how the auditory system extracts speech signals in the presence of noise, discrimination thresholds for the second formant frequency were predicted with simulations of auditory-nerve responses. These predictions employed either average-rate information or combined rate and timing information, and either populations of model fibers tuned across a wide range of frequencies or a subset of fibers tuned to a restricted frequency range. In general, combined temporal and rate information for a small population of model fibers tuned near the formant frequency was most successful in replicating the trends reported in behavioral data for formant-frequency discrimination. To explore the nature of the temporal information that contributed to these results, predictions based on model auditory-nerve responses were compared to predictions based on the average rates of a population of cross-frequency coincidence detectors. These comparisons suggested that average response rate (count) of cross-frequency coincidence detectors did not effectively extract important temporal information from the auditory-nerve population response. Thus, the relative timing of action potentials across auditory-nerve fibers tuned to different frequencies was not the aspect of the temporal information that produced the trends in formant-frequency discrimination thresholds.
A simulation study on tissue harmonic imaging with a single-element intravascular ultrasound catheter
Authors: Frijlink Martijn E. , Goertz David E. , Bouakaz Ayache , van der Steen Antonius F. W.
Published: September 2006

Recently, in vivo feasibility of tissue harmonic imaging with a mechanically rotated intravascular ultrasound (IVUS) catheter was experimentally demonstrated. To isolate the second harmonic signal content, a combination of pulse inversion and analog filtering was used. In this paper the development of a simulation tool to investigate nonlinear IVUS beams is reported, and the influence of transducer rotation and axial catheter-to-tissue motion on the efficiency of PI signal processing is evaluated. Nonlinear beams were simulated in homogeneous tissue-mimicking media at a transmit frequency of 20MHz, which resulted in second harmonic pressure fields at 40MHz. The competing effects of averaging and decorrelation between neighboring rf lines on the signal-to-noise ratio (SNR) were studied for a single point scatterer. An optimal SNR was achieved when lines were combined over 3°–3.75°. When the transducer was rotated with respect to point scatterers, simulating the acoustic response of tissue, the fundamental frequency suppression using PI degraded rapidly with increasing interpulse angles. The effect of axial catheter-to-tissue motion on the efficiency of pulse inversion seemed to be of less influence for realistic motion values. The results of this study will aid in the optimization of harmonic IVUS imaging systems.
A passive fathometer technique for imaging seabed layering using ambient noise
Authors: Siderius Martin , Harrison Chris H. , Porter Michael B.
Published: September 2006

A passive acoustics method is presented that uses the ocean ambient noise field to determine water depth and seabed sub-bottom layering. Correlating the noise field measured by two sensors one can recover a function that closely resembles the two-point Green’s function representing the impulse response between the two sensors. Here, a technique is described that is based on noise correlations and produces what is effectively a passive fathometer that can also be used to identify sub-bottom layers. In principle, just one or two hydrophones are needed—given enough averaging time. However, by combining the cross correlations of all hydrophone pairs in a vertical array a stronger signature can be obtained and this greatly reduces averaging time. With a moving (e.g., drifting) vertical array, the resulting algorithm yields both a map of the bottom depth (passive fathometer) and the locations of significant reflectors in the ocean sub-bottom. In this paper, the technique is described and illustrated using numerical simulations. Results are also shown from two experiments. In the first, ambient noise is taken on a fixed array in the 200–1500Hz frequency band and the second experiment uses a drifting array in the 50–4000Hz band.
Experimental demonstration of iterative time-reversed reverberation focusing in a rough waveguide. Application to target detection
Authors: Sabra Karim G. , Roux Philippe , Song Hee-Chun , Hodgkiss William S. , Kuperman W. A. , Akal Tuncay , Stevenson J. Mark
Published: September 2006

For most shallow water waveguides, the backscattered energy measured in a monostatic configuration is dominated by ocean bottom reverberation. A selected time-gated portion of the measured reverberation signal is used to provide a transfer function between a time-reversal array and a corresponding range interval on the bottom. Ultrasonic and at-sea experiments demonstrate the focusing capabilities of a time-reversal array along the rough bottom interface using these reverberation signals only. The iterative time-reversal technique facilitates robust focusing along the ocean bottom, with little signal processing effort involved and a priori information of the environment. This allows for enhanced detection and localization of proud or buried targets in complex shallow water environments. A passive implementation of the iterative time-reversal processing is used to construct reflectivity maps, similar to a sonar map, but with an enhanced contrast for the strongest reflectors (or scatterers), at the water-bottom interface. Ultrasonic and at-sea experiments show that targets on the seafloor located up to 400 wavelengths from a time-reversal array are detectable in the presence of bottom reverberation.
A comparison of underwater hearing sensitivity in bottlenose dolphins (Tursiops truncatus) determined by electrophysiological and behavioral methods
Authors: Houser Dorian S. , Finneran James J.
Published: September 2006

Variable stimulus presentation methods are used in auditory evoked potential (AEP) estimates of cetacean hearing sensitivity, each of which might affect stimulus reception and hearing threshold estimates. This study quantifies differences in underwater hearing thresholds obtained by AEP and behavioral means. For AEP estimates, a transducer embedded in a suction cup (jawphone) was coupled to the dolphin’s lower jaw for stimulus presentation. Underwater AEP thresholds were obtained for three dolphins in San Diego Bay and for one dolphin in a quiet pool. Thresholds were estimated from the envelope following response at carrier frequencies ranging from 10 to 150kHz. One animal, with an atypical audiogram, demonstrated significantly greater hearing loss in the right ear than in the left. Across test conditions, the range and average difference between AEP and behavioral threshold estimates were consistent with published comparisons between underwater behavioral and in-air AEP thresholds. AEP thresholds for one animal obtained in-air and in a quiet pool demonstrated a range of differences of −10 to 9dB (mean=3dB). Results suggest that for the frequencies tested, the presentation of sound stimuli through a jawphone, underwater and in-air, results in acceptable differences to AEP threshold estimates.
Inverting acoustic communication signals for the sound speed profile
Authors: Svensson Elin
Published: September 2006

Given data from a shallow-water acoustic communication experiment, the acoustic environmental parameters influencing the sound propagation conditions are estimated, particularly the sound speed profile. This inverse problem is solved using a differential evolution algorithm with an objective function measuring the mismatch between observed and modeled impulse response estimates. The model wave field is computed by a hybrid ray-trace/plane-wave method, and its accuracy is assessed in a related range-independent case using solutions obtained with a full-field transform integral method. The environmental parameters obtained by inversion reduce the mismatch between the modeled and the observed impulse response estimates, compared to the mismatch using a sound speed profile measured two days before the experiment. The resulting environmental model is used to investigate alternative source-receiver configurations and to predict the optimal transmitter depth.
Infidelity of DNA Synthesis in Vitro: Screening for Potential Metal Mutagens or Carcinogens
Authors: Sirover Michael A. , Loeb Lawrence A.
Published: October 2006

Thirty-one metal salts have been tested for their ability to affect the accuracy of DNA synthesis in vitro. All ten salts of metal carcinogens decreased the fidelity of DNA synthesis. Of the three metals which beforehand were considered to be possible mutagens or carcinogens, only one decreased fidelity. In contrast, 17 noncarcinogenic metal salts did not affect fidelity even when present at concentrations that were clearly inhibitory.
Melatonin: Effects on the Circadian Locomotor Rhythm of Sparrows
Authors: Turek Fred W. , McMillan Joseph P. , Menaker Michael
Published: October 2006

The continuous administration of low levels of melatonin via intraperitoneally placed Silastic capsules either (i) shortened the free-running period of activity or (ii) induced continuous activity in house sparrows (
Passer domesticus
) maintained in constant darkness. After the melatonin-filled capsules were removed, the period of the circadian rhythm of activity lengthened in rhythmic birds and normal rhythmicity was restored in continuously active birds. The results suggest that melatonin is involved in the physiological control of circadian rhythmicity in sparrows.
Studies on the Toxicity of Streptomycin for Man: A Preliminary Report
Authors: Hettig Robert A. , Adcock John D.
Published: October 2006

In this limited experience, tests of renal and hepatic function together with blood studies before and after the parenteral administration of streptomycin revealed no evidence of serious toxicity. Reactions, consisting of fever, arthralgias, and skin rashes as well as histamine-like effects, are believed to be due to impurities retained in the preparations of streptomycin employed in these studies.
What Retains Water in Living Cells?
Authors: Ling Gilbert N. , Walton Cheryl L.
Published: October 2006

Three types of evidence are presented showing that the retention of cell water does not necessarily depend on the possession of an intact cell membrane. The data agree with the concept that water retention in cells is due to multilayer adsorption on proteins and that the maintenance of the normal state of water relies on the presence of adenosine triphosphate as a cardinal adsorbent, controlling the protein conformations.
Immunofluorescence of Mitotic Spindles by Using Monospecific Antibody Against Bovine Brain Tubulin
Authors: Fuller Gerald M. , Brinkley B. R. , Boughter J. Mark
Published: October 2006

Monospecific antibody directed against bovine brain tubulin has been purified by affinity chromatography and tested against soluble tubulin and intact microtubules of brain and mitotic apparatus. Binding of the tubulin antibody to the mitotic spindle of rat kangaroo cells was demonstrated in all stages of mitosis by indirect immunofluorescence.
Inhibitory, GABAergic Nerve Terminals Decrease at Sites of Focal Epilepsy
Authors: Ribak Charles E. , Harris A. Basil , Vaughn James E. , Roberts Eugene
Published: October 2006

Using an immunocytochemical method for the localization of the γ-aminobutyric acid (GABA) synthesizing enzyme, glutamic acid decarboxylase (GAD), we have observed GABAergic nerve terminals distributed throughout all layers of normal monkey sensorimotor cortex. These terminals displayed ultrastructural characteristics that suggested that they arose from aspinous and sparsely spinous stellate neurons. In monkeys (
Macaca mulatta
and
M. fascicularis
) made epileptic by cortical application of alumina gel, a highly significant numerical decrease of GAD-positive nerve terminals occurred at sites of seizure foci indicating a functional loss of GABAergic inhibitory synapses. A loss of such inhibition at seizure foci could lead to epileptic activity of cortical pyramidal neurons.
Bone Resorption Restored in Osteopetrotic Mice by Transplants of Normal Bone Marrow and Spleen Cells
Authors: Walker Donald G.
Published: October 2006

Capacity to resorb bone and calcified cartilage was restored permanently in mice with inherited osteopetrosis by the intravenous administration of cell suspensions prepared from spleen and bone marrow of normal littermates. Beginning near active growth plates as early as 2 weeks after transplantation, replacement of the abnormal spongiosa continued until medullary cavities were fully expanded.
Localized Desensitization of
Limulus
Photoreceptors Produced by Light or Intracellular Calcium Ion Injection
Authors: Fein A. , Lisman J.
Published: October 2006

Spots of light were used to measure the light sensitivity of spatially separated regions of single
Limulus
photoreceptors. The desensitization caused by irradiating part of the cell was largest in the irradiated region. The desensitization caused by intracellular calcium ion injection was largest near the injection site. The spread of desensitization away from the injection site suggests that calcium ion can diffuse over neuronal dimensions, but that the effective rate of diffusion is not so high as to abolish calcium gradients. The results are compatible with the previously proposed hypothesis that a rise in the intracellular calcium ion concentration mediates light adaptation.
Polyzonimine: A Novel Terpenoid Insect Repellent Produced by a Milliped
Authors: Smolanoff J. , Kluge A. F. , Meinwald J. , McPhail A. , Miller R. W. , Hicks Karen , Eisner T.
Published: October 2006

A nitrogen-containing terpene 6,6-dimethyl-2-azaspiro[4.4]non-1-ene (
polyzonimine
) was isolated from the defensive secretion of the milliped
Polyzonium rosalbum
. Polyzonimine, which is repellent to such natural enemies of the milliped as ants, acts as a topical irritant to insects (10
-4
M
induces scratching in cockroaches). Its structure was confirmed by a five-step synthesis starting from 2,2-dimethyl-7-oxabicyclo[4.1.0]heptane.
Retinal Degeneration Associated with Taurine Deficiency in the Cat
Authors: Hayes K. C. , Carey Richard E. , Schmidt Susan Y.
Published: October 2006

A degeneration of the retinal photoreceptor cells develops in cats when casein is the source of dietary protein. Amino acid profiles indicate that the degeneration is associated with a selective decrease in plasma and retinal taurine concentrations. A sulfur amino acid deficit in the casein diet combined with specific amino acid requirements of the cat appear related to this unique expression of taurine deficiency.
Tetrodotoxin: Occurrence in Atelopid Frogs of Costa Rica
Authors: Kim Yong H. , Brown George B. , Mosher Harry S. , Fuhrman Frederick A.
Published: October 2006

The potent neurotoxin tetrodotoxin, which has previously been found in puffer fish of the order Tetraordontiformes, a goby (
Gobius criniger
), and the California newt (
Taricha torosa
), has now been identified in the skins of frogs of the genus
Atelopus
from Costa Rica.
Organization of the Immune Response Genes
Authors: Uhr Jonathan W. , Capra J. Donald , Vitetta Ellen S. , Cook Richard G.
Published: October 2006

The I region of the major histocompatibility complex contains immune response genes that display considerable polymorphism; that is, there are many alleles at each locus. These genes regulate the immune response to antigen by mediating intercellular communication among lymphoreticular cells. An analysis of the primary structure of the products of two subregions of
I
(
I-A
,
I-E
/
C
) was undertaken in order to understand the genetic organization of the region, the evolution of the genes and, eventually, their function.
Chronotypic Action of Theophylline and of Pentobarbital as Circadian Zeitgebers in the Rat
Authors: Ehret Charles F. , Potter Van R. , Dobra Kenneth W.
Published: October 2006

In the rat the deep body temperature rhythm, monitored by telemetry, can be reset in a predictable direction by a stimulant (theophylline) and by a depressant (pentobarbital). When the drugs are applied immediately before or during the early active phases of the circadian cycle, the rhythm is set back (phase delay). When applied later, past the thermal peak, theophylline, but not pentobarbital, shifts the rhythm ahead (phase advance). Theophylline and pentobarbital in addition to having a number of already established pharmacological properties are now further identified as chronobiotics: they are drugs that may be used to alter the biological time structure by rephasing a circadian rhythm.
Strain Differences During Intraventricular Infusion of Norepinephrine: Possible Role of Receptor Sensitivity
Authors: Segal David S. , Geyer Mark A. , Weiner Barry E.
Published: October 2006

Two rat strains previously shown to differ with respect to behavioral activity, regional brain tyrosine hydroxylase activity, and norepinephrine-elicited accumulation of adenosine 3′, 5′-monophosphate exhibited differential behavioral responsiveness during the intraventricular infusion of norepinephrine. The results are interpreted in terms of differential catecholamine receptor sensitivity.
Exposure to Asbestos in the Use of Consumer Spackling, Patching, and Taping Compounds
Authors: Rohl A. N. , Langer A. M. , Selikoff I. J. , Nicholson W. J.
Published: October 2006

Analysis of representative samples of spackling, patching, and jointing compounds, purchased at retail stores in the New York City area, has shown that some contain asbestos minerals as well as other biologically active substances. Measurements suggest that home repair work involving the use of such materials may result in exposure to dust at concentrations sufficient to produce disease.
Recruitment Dynamics in Complex Life Cycles
Authors: Roughgarden Jonathan , Gaines Steven , Possingham Hugh
Published: October 2006

Organisms living in the marine rocky intertidal zone compete for space. This, together with predation, physical disruption, and differing species tolerances to physiological stress, explains the structure of the ecological communities at some sites. At other sites the supply of larvae is limiting, and events in the offshore waters, such as wind-driven upwelling, explain the composition of intertidal communities. Whether the community ecology at a site is governed by adult-adult interactions within the site, or by limitations to the supply of larvae reaching the site, is determined by the regional pattern of circulation in the coastal waters. Models combining larval circulation with adult interactions can potentially forecast population fluctuations. These findings illustrate how processes in different ecological habitats are coupled.
The Greenhouse and Antigreenhouse Effects on Titan
Authors: McKay Christopher P. , Pollack James B. , Courtin Régis
Published: October 2006

There are many parallels between the atmospheric thermal structure of the Saturnian satellite Titan and the terrestrial greenhouse effect; these parallels provide a comparison for theories of the heat balance of Earth. Titan's atmosphere has a greenhouse effect caused primarily by pressure-induced opacity of N
2
, CH
4
, and H
2
. H
2
is a key absorber because it is primarily responsible for the absorption in the wave number 400 to 600 cm
-1
"window" region of Titan's infrared spectrum. The concentration of CH
4
, also an important absorber, is set by the saturation vapor pressure and hence is dependent on temperature. In this respect there is a similarity between the role of H
2
and CH
4
on Titan and that of CO
2
and H
2
O on Earth. Titan also has an antigreenhouse effect that results from the presence of a high-altitude haze layer that is absorbing at solar wavelengths but transparent in the thermal infrared. The antigreenhouse effect on Titan reduces the surface temperature by 9 K whereas the greenhouse effect increases it by 21 K. The net effect is that the surface temperature (94 K) is 12 K warmer than the effective temperature (82 K). If the haze layer were removed, the antigreenhouse effect would be greatly reduced, the greenhouse effect would become even stronger, and the surface temperature would rise by over 20 K.
3.4-Billion-Year-Old Biogenic Pyrites from Barberton, South Africa: Sulfur Isotope Evidence
Authors: Ohmoto Hiroshi , Kakegawa Takeshi , Lowe Donald R.
Published: October 2006

Laser ablation mass spectroscopy analyses of sulfur isotopic compositions of microscopic-sized grains of pyrite that formed about 3.4 billion years ago in the Barberton Greenstone Belt, South Africa, show that the pyrite formed by bacterial reduction of seawater sulfate. These data imply that by about 3.4 billion years ago sulfate-reducing bacteria had become active, the oceans were rich in sulfate, and the atmosphere contained appreciable amounts (>>10
-13
of the present atmospheric level) of free oxygen.
Tetrachlorodibenzodioxin: An Accidental Poisoning Episode in Horse Arenas
Authors: Carter Coleman D. , Kimbrough Renate D. , Liddle John A. , Cline Richard E. , Zack Matthew M. , Barthel William F. , Koehler Robert E. , Phillips Patrick E.
Published: October 2006

Tetrachlorodibenzodioxin was identified as the apparent cause of an outbreak of poisoning in humans, horses, and other animals. Exposure was related to the spraying of contaminated waste oil on riding arenas for dust control. The contamination resulted from the improper disposal of a toxic industrial waste. The pathologic effects and chemical identification of tetrachlorodibenzodioxin are described.
Sequence of the Cloned Gene for the Constant Region of Murine γ2b Immunoglobulin Heavy Chain
Authors: Tucker Philip W. , Marcu Kenneth B. , Newell Nanette , Richards Julia , Blattner Frederick R.
Published: October 2006

The complete nucleotide sequence of the γ2b constant region gene cloned from BALB/c liver DNA is reported. The sequence of approximately 1870 base pairs includes the 5′ flanking, 3′ untranslated, and 3′ flanking regions and three introns. The Cγ2b coding region is divided by these introns into four segments corresponding to the homology domains and hinge region of the protein. The introns separating the hinge from the C
H
2 domain and the C
H
2 from the C
H
3 domain are small (106 and 119 base pairs). A larger intervening sequence of 314 base pairs separates the C
H
1 and hinge regions. The stretch of DNA comprising this large intron plus the hinge shows a strong homology with the other C
H
domains.
Melatonin: Antigonadal and Progonadal Effects in Male Golden Hamsters
Authors: Turek Fred W. , Desjardins Claude , Menaker Michael
Published: October 2006

Melatonin induced marked testicular regression in hamsters maintained on photostimulatory long days (light-dark 14 : 10). In animals maintained on nonstimulatory short days (light-dark 6 : 18), small amounts of melatonin (50 micrograms per day; 100 millimeters capsule length) prevented testicular regression; but testicular atrophy occurred in hamsters that received larger amounts of melatonin (75 to 100 micrograms per day; 150 to 200 millimeters capsule length) and in control hamsters that received none. The results demonstrate that melatonin can exert either pro- or antigonadal effects and emphasize that the effects of melatonin on the testis cannot be properly assessed unless account is taken of the dosage and mode of melatonin administration and the photoperiod on which experimental animals are maintained.
Modification of Cortical Orientation Selectivity in the Cat by Restricted Visual Experience: A Reexamination
Authors: Stryker Michael P. , Sherk Helen
Published: October 2006

Recent reports have stated that the orientation selectivity of cells in the cat's visual cortex can be biased by limiting the early visual environment to stripes of one orientation. Data obtained from seven kittens using systematic and quantitative sampling of preferred orientation, together with a blind procedure, do not show a bias toward the orientation presented in one type of restricted rearing environment.
Immunoglobulin E Antibodies to Pollen Allergens Account for High Percentages of Total Immunoglobulin E Protein
Authors: Gleich Gerald J. , Jacob Gregory L.
Published: October 2006

The quantities of immunoglobulin E (IgE) antibodies to grass or ragweed allergens were measured by an immunoabsorption in the serums of patients sensitive to one of these allergens. IgE antibodies to grass or ragweed allergens accounted for means of 30 and 29 percent of the total IgE protein. After the ragweed pollination season, the levels of serum IgE antibodies to ragweed allergens rose dramatically and in postpollination serums they accounted for 39 percent of the total IgE protein with a range from 13 to 50 percent.
Social Class and Frequency of XYY and XXY
Authors: Walzer Stanley , Gerald Park S.
Published: October 2006

The karyotype and paternal social class were determined for 10,348 consecutively born males. No significant difference in paternal social class was associated with the occurrence of the XYY or the XXY karyotype. This argues against the suggestion that socioeconomic factors significantly affect the frequency of the nondisjunctional events leading to these chromosome abnormalities.
Double Branched Flicker Fusion Curves from the All-Rod Skate Retina
Authors: Green Daniel G. , Siegel Irwin M.
Published: October 2006

Electrical responses from the skate retina will only follow flicker up to frequencies of 5 hertz when intensities are below rod saturation. At greater luminances, the eye responds to rates as high as 30 hertz. As a result, a plot of critical flicker fusion as a function of intensity is a double branched curve. It seems that prolonged stimulation of skate rods, at high intensities, permits them to change their temporal response characteristics so that they follow high frequencies much as cones do in the duplex retina.
Lysergic Acid Diethylamide: Effect on Histone Acetylation in Rabbit Brain
Authors: Brown Ian R. , Liew C. C.
Published: October 2006

Lysergic acid diethylamide increased acetylation of histones in rabbit cerebral hemispheres and midbrain 30 minutes after intravenous administration of the drug at doses of 10 and 100 micrograms per kilogram of body weight. Evidence for the stimulation of acetylation in individual histone bands was obtained after separation by electrophoresis on polyacrylamide gels.
Cancer by County: New Resource for Etiologic Clues
Authors: Hoover Robert , Mason Thomas J. , McKay Frank W. , Fraumeni Joseph F.
Published: October 2006

Mapping of U. S. cancer mortality by county has revealed patterns of etiologic significance. The patterns for bladder cancer in males point to industrial determinants: some are known (chemical manufacturing) but others (automobile and machinery manufacturing) represent new leads for epidemiologic study. By contrast, the geographic clusters of high rates of stomach cancer in both sexes are consistent with ethnic susceptibility.
Stage-Specific Switches in Histone Synthesis During Embryogenesis of the Sea Urchin
Authors: Cohen Leonard H. , Newrock Kenneth M. , Zweidler Alfred
Published: October 2006

Histones H2A and H2B of the sea urchin embryo have been resolved by new methods into components that are synthesized at different stages of development. One form of H2A and one form of H2B are synthesized only during the period from fertilization to the blastula stage. Subsequently, two other types of H2A and H2B molecules are synthesized. In addition, a histonelike protein was detected which is synthesized only from fertilization until the 16-cell stage when the synthesis of still another H2A-like protein begins. None of the late-appearing forms are derived from histone polypeptide chains synthesized earlier in development. Since the early components do not disappear after their synthesis stops, these modulations of histone synthesis lead to an increase in histone multiplicity, concomitant with the beginning of cell diversification and a decrease in cell division rate.
Electron Microscopy: Cytology of Cell Fractions
Authors: Novikoff Alex B.
Published: October 2006

It should be evident from this brief account that electron microscopy of thin sections is an invaluable asset in the study of fractions isolated by differential centrifugation. I have tried to indicate how the integrity of particles, purity of fractions, and the existence of new particles can be established through its use.

I have also suggested the desirability of a common terminology for all cytology—classic, electron-microscopic, and biochemical. Some have expressed the opinion that neutral terms such as
alpha, beta
, and
gamma membranes
are more useful than
ergastoplasm, Golgi apparatus
, and so forth. As helpful as such neutral terms may be in
describing
intracellular structures, they do not appear to me to substitute for historically rooted cytological names.

Note added in proof
: Since this article went to press there has appeared an important article by G. E. Palade and P. Siekevitz. These authors consider that the vesicles without granules found in the microsome fraction were "probably derived from the smooth surfaced parts of the endoplasmic reticulum." The latter were found to be continuous with the granule-studded membranes; "the two varieties of profiles represent local differentiation within a common system." The authors confirm the finding of Rouiller and Novikoff
et al.
of the dense bodies adjacent to the bile canaliculi and describe their presence in the microsome fraction as a "minor component."
"Serotonin Depression"—A Biochemical Subgroup Within the Affective Disorders?
Authors: Åsberg Marie , Thorén Peter , Traskman Lil , Bertilsson Leif , Ringberger Viviann
Published: October 2006

The distribution of 5-hydroxyindoleacetic acid (5-HIAA) concentrations in the cerebrospinal fluid of 68 depressed patients was bimodal. Twenty-nine percent of the patients were in the lower mode, with a concentration of 5-HIAA below 15 nanograms per milliliter. Although there were no differences in overall severity of depression between the two modes, there was a significant correlation between the concentration of 5-HIAA and severity of depression in the lower, but not in the upper, mode. The finding suggests the existence of a biochemical subgroup of depressive disorder, characterized by a disturbance of serotonin turnover.
Californium-252 Plasma Desorption Mass Spectroscopy
Authors: Macfarlane R. D. , Torgerson D. F.
Published: October 2006

We have shown that
252
Cf-PDMS is capable of producing mass spectra of quasi-molecular ions for a wide variety of compounds, including amino acids, moderately large peptides, nucleotides, and natural products. Positive and negative ion mass spectra can be obtained, and in many cases quasi-molecular ions are observed in both. The method is nondestructive, as only a relatively few molecules are used and samples can be recovered after the measurement is made. Fragmentation patterns are obtained which can yield structure information. The present sensitivity of the method is at the nanogram level and there are possibilities for reducing this to picograms. The mass resolution is sufficient to give elemental identification up to mass 500. This may be extended to higher masses with improved time-of-flight techniques. There are indications that
252
Cf-PDMS may extend the mass range of molecules that can be studied to as high as 3000 or more.
High Resolution of Human Chromosomes
Authors: Yunis Jorge J.
Published: October 2006

G-band prophase chromosomes from synchronized cells permit a high degree of resolution not previously attained in the study of chromosome structure and birth defects in man.
Pattern-Analyzing Memory
Authors: Kolers Paul A.
Published: October 2006

College students reread text after an interval of 13 to 15 months more rapidly than they read new matter taken from the same sources. The results implicate a memory system at the level of pattern analysis that seems to be distinguishable from memory of syntactic and semantic features of text.
Ingestion of
Streptococcus mutans
Induces Secretory Immunoglobulin A and Caries Immunity
Authors: Michalek Suzanne M. , McGhee Jerry R. , Mestecky Jiri , Arnold Roland R. , Bozzo Lourenco
Published: October 2006

Ingestion of killed cells of a highly cariogenic strain of
Streptococcus mutans
induced specific antibodies in both saliva and milk but not in serum of gnotobiotic rats. These antibodies were associated with the immunoglobulin A class. When infected with
Streptococcus mutans
, orally immunized animals developed significantly fewer carious lesions than nonimmunized infected controls.
A Multifunctional Aqueous Channel Formed by CFTR
Authors: Hasegawa Hajime , Skach William , Baker Oliver , Calayag M. Clara , Lingappa V. , Verkman A. S.
Published: October 2006

The cystic fibrosis gene product (CFTR) is a complex protein that functions as an adenosine 3,5-monophosphate (cAMP)-stimulated ion channel and possibly as a regulator of intracellular processes. In order to determine whether the CFTR molecule contains a functional aqueous pathway, anion, water, and urea transport were measured in
Xenopus
oocytes expressing CFTR. Cyclic AMP agonists induced a Cl
-
conductance of 94 microsiemens and an increase in water permeability of 4 × 10
-4
centimeter per second that was inhibited by a Cl
-
channel blocker and was dependent on anion composition. CFTR has a calculated single channel water conductance of 9 × 10
-13
cubic centimeter per second, suggesting a pore-like aqueous pathway. Oocytes expressing CFTR also showed cAMP-stimulated transport of urea but not the larger solute sucrose. Thus CFTR contains a cAMP-stimulated aqueous pore that can transport anions, water, and small solutes. The results also provide functional evidence for water movement through an ion channel.
Extracranial Responses to Acoustic Clicks in Man
Authors: Geisler C. D. , Frishkopf L. S. , Rosenblith W. A.
Published: October 2006

Electronic averaging of potentials recorded from the human scalp reveals the presence of small average responses following the presentation of click stimuli. These responses are first detectable near the subject's psychophysical threshold and vary in amplitude with click intensity. It is suggested that the short-latency components of these responses are cortical in origin.
Phenylalanine Hydroxylation Cofactor in Phenylketonuria
Authors: Kaufman Seymour
Published: October 2006

The enzymatic conversion of phenylalanine to tyrosine had previously been shown to require a nonprotein cofactor. It has now been demonstrated by direct assay that the cofactor is present in phenylketonuric liver samples. The lack of a functional phenylalanine hydroxylating system in phenylketonuria is not due to the absence of the cofactor.
Nemin: a Morphogenic Substance Causing Trap Formation by Predaceous Fungi
Authors: Pramer David , Stoll Norman R.
Published: October 2006

Broths in which the nematode
Neoaplectana glaseri
had developed axenically caused the mycelium of the predaceous fungus
Arthrobotrys conoides
to differentiate into traps. The active principle was extracted from worm-free culture filtrates and named "nemin." The identity of nemin remains to be established.
Metabolically Induced Precipitation of Trace Elements from Sea Water
Authors: Graham John W.
Published: October 2006

The presence of organic material in some manganese-rich nodules suggests that the nodules are of biological origin. This suggestion leads to the proposal that in sea water, heavy metals get protection from hydrolysis by organic complexing; parts of these complexes become metabolized, the remaining parts then precipitate. These processes would explain a number of interesting observations.
Intellectual Level Measured by Army Classification Battery and Serum Uric Acid Concentration
Authors: Stetten DeWitt , Hearon John Z.
Published: October 2006

In a group of 817 individuals inducted into the U.S. Army, serum uric acid concentration was measured. The values were compared with scores secured on intelligence tests used at the Army reception center. A significant but low level of positive correlation between the two sets of values was found.
Metabolism of the Gerbil,
Meriones unguiculatus
Authors: Robinson Paul F.
Published: October 2006

The critical temperature for the Mongolian gerbil,
Meriones unguiculatus
, is determined to be 30°C. The zone of thermal neutrality extends to 40°C. This species possesses a high degree of tolerance for heat and has a greater capacity for temperature regulation than is reported for many of the desert rodents.
Magnitude of the Moon Illusion as a Function of the Age of the Observer
Authors: Leibowitz H. , Hartman T.
Published: October 2006

The diminution in the apparent size of an object when viewed overhead as compared with its apparent size in the horizontal plane is greater for children than for adults. This relationship, of which the well-known moon illusion is a special case, is interpreted to be a consequence of the normal development of size constancy.
Left-to-Right Shunt Detection by an Intravascular Electrode with Hydrogen as an Indicator
Authors: Clark Leland C. , Bargeron L. M.
Published: October 2006

Hydrogen gas crosses the pulmonary membrane and dissolves in blood, and it therefore appears immediately and in high concentration in the left heart and later and in lower concentration in the right heart. The hydrogen-sensing, platinum black-tipped catheter is uniquely sensitive in detecting the left-to-right shunts.
Induced Synthesis of Liver Microsomal Enzymes Which Metabolize Foreign Compounds
Authors: Conney A. H. , Gillette James R. , Inscoe Joseph K. , Trams Eberhard R. , Posner Herbert S.
Published: October 2006

The administration of 3,4-benzpyrene to rats markedly increases the activities of certain liver microsomal enzymes which metabolize foreign compounds. Evidence based on studies of enzyme induction is presented which suggests the presence in liver microsomes of several enzymes which can catalyze the same type of reaction.
Transport of Strontium-90 in Runoff
Authors: Menzel Ronald G.
Published: October 2006

Only a small portion of the strontium-90 that fell on cultivated soils was removed in runoff. The concentration of strontium-90 was usually about 10 times higher in the soil carried by the runoff than in the soil from the plow layer of the plots. Thus, a considerable concentration of Sr
90
could occur in areas where runoff sediments accumulate.
Toxicity of Bacterial Exotoxins by the Oral Route
Authors: Lamanna Carl
Published: October 2006

Reports to the contrary notwithstanding, both tetanus and diphtheria toxins are demonstrably orally toxic. The significance of this finding is considered in relation to the definition of those factors which are determinants of the potency of bacterial protein toxins by the oral route.
Calcium Entry Through Kainate Receptors and Resulting Potassium-Channel Blockade in Bergmann Glial Cells
Authors: Müller T. , Möller T. , Berger T. , Schnitzer J. , Kettenmann H.
Published: October 2006

Glutamate receptors, the most abundant excitatory transmitter receptors in the brain, are not restricted to neurons; they have also been detected on glial cells. Bergmann glial cells in mouse cerebellar slices revealed a kainate-type glutamate receptor with a sigmoid current-to-voltage relation, as demonstrated with the patch-clamp technique. Calcium was imaged with fura-2, and a kainate-induced increase in intracellular calcium concentration was observed, which was blocked by the non-
N
-methyl-D-aspartate (NMDA) glutamate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and by low concentrations of external calcium, indicating that there was an influx of calcium through the kainate receptor itself. The entry of calcium led to a marked reduction in the resting (passive) potassium conductance of the cell. Purkinje cells, which have glutamatergic synapses, are closely associated with Bergmann glial cells and therefore may provide a functionally important stimulus.
Increased Stress and Effectiveness of Placebos and "Active" Drugs
Authors: Beecher Henry K.
Published: October 2006

Evidence is presented to indicate that placebos are far more effective in producing carefully defined relief of pathological pain than they are in the case of experimental pain. This is construed as further support for the view that placebos are more effective when stress is great than they are when stress is not so great. A similar situation holds for morphine. Certain drugs are effective in relieving visceral sensations only if an essential psychological state is present. This is, in effect, a new principle of drug action.
First Natural Occurrence of Coesite
Authors: Chao E. C. T. , Shoemaker E. M. , Madsen B. M.
Published: October 2006

Coesite, the high-pressure polymorph of SiO
2
, hitherto known only as a synthetic compound, is identified as an abundant mineral in sheared Coconino sandstone at Meteor Crater, Arizona. This natural occurrence has important bearing on the recognition of meteorite impact craters in quartz-bearing geologic formations.
Licking Rates of Albino Rats
Authors: Keehn J. D. , Arnold E. M. M.
Published: October 2006

Local licking rates of eight albino rats, when the rats were given tap water at the end of a short runway after 23 hours of water deprivation, averaged a little over seven licks per second. Small variations within sessions were found, rates being slightly but consistently higher at the beginning than later on in sessions. Inter-session and individual differences were also observed, but were only of the order of one lick per second. Within practical limits, it appears that licking rates of rats are constant.
Suppressive Effects of 2-Thiouracil on Differentiation and Flowering in
Cannabis sativa
Authors: Heslop-Harrison J.
Published: October 2006

The pyrimidine, 2-thiouracil, partly annuls the effect of photoperiodic induction in the short-day plant,
Cannabis sativa
L., when it is supplied at the onset of the dark period in quantities of 15-30 μg per plant. This treatment also produces aberrations in cellular differentiation in the leaves. Tracer studies show that 2-thiouracil becomes bound in cellular ribonucleic acid, which suggests that the effects on morphogenesis are due to interference with nucleic acid metabolism.
Syntaxin: A Synaptic Protein Implicated in Docking of Synaptic Vesicles at Presynaptic Active Zones
Authors: Bennett Mark K. , Calakos Nicole , Scheller Richard H.
Published: October 2006

Synaptic vesicles store neurotransmitters that are released during calcium-regulated exocytosis. The specificity of neurotransmitter release requires the localization of both synaptic vesicles and calcium channels to the presynaptic active zone. Two 35-kilodalton proteins (p35 or syntaxins) were identified that interact with the synaptic vesicle protein p65 (synaptotagmin). The p35 proteins are expressed only in the nervous system, are 84 percent identical, include carboxyl-terminal membrane anchors, and are concentrated on the plasma membrane at synaptic sites. An antibody to p35 immunoprecipitated solubilized N-type calcium channels. The p35 proteins may function in docking synaptic vesicles near calcium channels at presynaptic active zones.
Membrane Depolarization Induces p140
trk
and NGF Responsiveness, but Not p75
LNGFR
, in MAH Cells
Authors: Birren Susan J. , Verdi Joseph M. , Anderson David J.
Published: October 2006

Nerve growth factor (NGF) is required for the maturation and survival of sympathetic neurons, but the mechanisms controlling expression of the NGF receptor in developing neuroblasts have not been defined. MAH cells, an immortalized sympathoadrenal progenitor cell line, did not respond to NGF and expressed neither low-affinity NGF receptor (p75) nor p140
trk
messenger RNAs. Depolarizing concentrations of potassium chloride, but none of a variety of growth factors, induced expression of p140
trk
but not p75 messenger RNA. A functional response to NGF was acquired by MAH cells under these conditions, suggesting that expression of p75 is not essential for this response. Depolarization also permitted a relatively high proportion of MAH cells to develop and survive as neurons in fibroblast growth factor and NGF. These data establish a relation between electrical activity and neurotrophic factor responsiveness in developing neurons, which may operate in the functioning of the mature nervous system as well.
Self-Absorption Correction for Isotopes Emitting Weak Beta Rays
Authors: Massini P.
Published: October 2006

The shape of the self-absorption correction curve of β-emitters is not universal but depends on the geometrical arrangement of the sample and counting device. This may explain why the correction factor defined by Hendler is not always linearly related to the thickness of the sample.
Distinct "Feeding" and "Hunger Motivating" Systems in the Lateral Hypothalamus of the Rat
Authors: Morgane P. J.
Published: October 2006

Electrodes were implanted in the middle hypothalamus of rats to determine the neural organization of the "feeding" centers. Stimulations of the farand midlateral hypothalamic area produced feeding responses in sated animals, but only the former caused sated animals to cross an electrified grill to press a lever for food. After lesions had been made in the medial forebrain bundle, however, stimulations in the far-lateral hypothalamic area resulted in feeding in sated animals but failure to cross the electrical barrier to press a lever for food. Simultaneous far-lateral and "satiety" center stimulations produced feeding in sated animals but failed to "motivate" grill-crossing behavior.
One-Trial Interhemispheric Transfer of a Learning Engram
Authors: Russell I. Steele , Ochs S.
Published: October 2006

By using spreading depression to decorticate temporarily one hemisphere in rats, a learning trace was established in the opposite functional hemisphere. Spontaneous transfer of the engram from the
trained
hemisphere to the untrained hemisphere does not occur when both hemispheres are functional. If, however, the animal was allowed to make one reinforced response, complete transfer of the engram to the untrained hemisphere occurred.
Hormonal Control of Sex Attractant Production in the Cuban Cockroach
Authors: Barth Robert H.
Published: October 2006

Virgin females of
Byrsotria fumigata
(Guérin) and several other species of Blattidae produce volatile substances which attract males and release in them characteristic precopulatory behavior. The removal of the corpora allata from females shortly after the imaginal molt results in a failure of production of sex attractant, as assayed by male behavior. Implantation of corpora allata can effect recovery.
Gibberellin as Sex Regulator in
Ricinus communis
Authors: Shifriss Oved
Published: October 2006

Spraying monoecious inbreds with gibberellin A
3
can markedly increase their female tendency. The effect of this substance upon sex appears to simulate the action of long days.
Localization of Targets for Anti-Ulcer Drugs in Cells of the Immune System
Authors: Mezey Éva , Palkovits Miklós
Published: October 2006

The gastric mucosa consists of the epithelium, which lines the lumen, the lamina propria, and the muscularis mucosae. The targets of drugs used to treat stomach and duodenal ulcers are thought to be the acid-secreting parietal cells of the epithelium. However, immune cells in the lamina propria are the only cells that showed detectable messenger RNAs for histamine, muscarinic, gastrin, and dopamine receptors by in situ hybridization histochemistry. None of the epithelial cells expressed any of these messenger RNAs. Thus, the targets of antiulcer drugs seem to be cells of the immune system in the gut and not parietal cells, as generally believed. This conclusion may revise the thinking about ulcer formation and may shed light on the etiology of such chronic small intestinal diseases as Crohn's disease.