bluuebunny/crossref_metadata_2025 huggingface dataset:
Io: Evidence for Silicate Volcanism in 1986
Authors: Johnson Torrence V. , Veeder Glenn J. , Matson Dennis L. , Brown Robert H. , Nelson Robert M. , Morrison David
Published: October 2006

Infrared observations of Io during the 1986 apparition of Jupiter indicate that a large eruptive event occurred on the leading side of Io on 7 August 1986, Universal Time. Measurements made at 4.8, 8.7, and 20 micrometers suggest that the source of the event was about 15 kilometers in radius with a model temperature of ∼900 Kelvin. Together with previously reported events, these measurements indicate that high-temperature volcanic activity on the leading side of Io may be more frequent than previously thought. The inferred temperature is significantly above the boiling point of sulfur in a vacuum (715 Kelvin) and thus constitutes strong evidence for active silicate volcanism on the surface of Io.
AAAS Meeting Draws a Crowd
Authors: Norman Colin , Booth William
Published: October 2006

The annual meeting of the AAAS, held in San Francisco on 14 to 19 January, attracted the largest turnout for several years. More than 6000 are estimated to have attended. The meeting, which was held in conjunction with the winter meeting of the American Physical Society and the annual meeting of the American Association of Physics Teachers, was reminiscent in some respects of the big AAAS annual gatherings of the late 1960s and early 1970s—even down to the presence of demonstrators, this year from the animal rights movement. Some highlights of the more than 250 sessions:
Large-Scale, Low-Amplitude Bedforms (Chevrons) in the Selima Sand Sheet, Egypt
Authors: Maxwell Ted A. , Haynes C. Vance
Published: October 2006

Landsat images of the Selima sand sheet in southwestern Egypt display alternating light and dark chevron-shaped patterns that occur downwind from low scarps and major dune fields. Images acquired between 1972 and 1988 indicate that these features move as discrete bedforms at a rate of up to 500 meters per year. Extremely long-wavelength (130 to 1200 meters), low-amplitude (10 to 30 centimeters) bedforms were measured in the field; the light chevrons seen in the orbital data may be thin accumulations of active sand sheet deposits in the lee of these bedforms. Dark chevrons contain an admixture of coarse-granule lag deposits that are continually winnowed by aeolian erosion on the windward sides of the large bedforms. Sediment transport budgets derived from orbital and field analyses suggest net movement of up to 83,000 cubic meters per year for a single light chevron; such measurements can be used as a check on similar calculations from dunes and other smaller scale features to determine sand transport budgets for large areas of the eastern Sahara.
Improved and Safer Nuclear Power
Authors: Taylor John J.
Published: October 2006

Recent progress in advanced nuclear power development in the United States is revealing high potential for nuclear reactor systems that are smaller and easier to operate than the present generation. Passive, or intrinsic, characteristics are applied not only to provide inherent stability of the chain reaction but also to ensure continued cooling of the fuel and its containment systems even if a major breakdown of the normal cooling and control functions were to occur. The chance of a severe accident is thereby substantially reduced. The plant designs that are emerging are simpler and more rugged, have a longer life span, and place less burden on equipment and operating personnel. Modular design concepts and design standardization are also used to reduce construction time and engineering costs, giving promise that the cost of generating power from these systems will be competitive with alternative methods.
Microearthquake Imaging of the Parkfield Asperity
Authors: Malin P. E. , Blakeslee S. N. , Alvarez M. G. , Martin A. J.
Published: October 2006

Microearthquake data from a downhole seismometer network on the San Andreas fault appear to outline two aseismic asperities that may correspond to the locations of the foreshocks and main shocks of the Parkfield characteristic earthquakes. The source parameters of the microearthquakes show that a few of the earthquakes have significantly higher stress drops than most. Furthermore, the magnitude-frequency statistics suggest that at local magnitude 0.6, the cumulative number of small events begins to fall off the usual Gutenberg-Richter (
b
= -1) relation, in which the number of events increases exponentially with decreasing magnitude. The downhole seismometer data establish a baseline from which the evolution of the earthquake process at Parkfield can be monitored and suggest that different mechanical conditions than those that lead to the typical Gutenberg-Richter relation may be operating for the smallest of Parkfield microearthquakes.
Corn and Culture in Central Andean Prehistory
Authors: Johannessen Sissel , Hastorf Christine A.
Published: October 2006

The prehistoric development and spread of domesticated maize varieties in the highlands of Peru, unlike the drier coastal deserts, is little known because ancient maize remains in this area survive mainly as fragments, kernels, and cob parts. An analysis of fragmented charred maize from prehistoric households (A.D.450 to 1500) in the Mantaro Valley reveals a developmental sequence of maize varieties for Highland Peru. The evidence indicates an adoption of large-kernelled maize varieties beginning in the Late Intermediate (A.D. 1000). This is centuries later than a similar change in maize, associated with the Wari expansion, that occurred in coastal areas, and indicates minimal Wari impact in the Mantaro Valley.
Downregulation of L3T4
+
Cytotoxic T Lymphocytes by Interleukin-2
Authors: Shih Charles C.-Y. , Truitt Robert L.
Published: October 2006

Proliferation of activated cytotoxic T lymphocytes (CTLs) that recognize foreign histocompatibility antigens is induced by interleukin-2, a potent immunoregulatory molecule originally described as T cell growth factor. Interleukin-2 (IL-2) is widely used to isolate and induce clonal expansion of CTLs for functional studies in vitro and in vivo. However, in studies with CTLs specific for class I and class II histocompatibility antigens, IL-2 rapidly downregulated the lytic activity of some class II-specific CTLs in a time- and dose-dependent manner. Lytic activity of L3T4
+
CTLs specific for the murine class II antigen I-E
k
was repeatedly up- and downregulated in vitro by alternate exposure to specific (alloantigen) and nonspecific (recombinant IL-2) signals, respectively. These results demonstrate that some CTLs modulate their functional property (cytolysis) while undergoing IL-2-driven cell proliferation without loss of antigen specificity or ability to revert to a lytic phenotype.
Explosive Molecular Ionic Crystals
Authors: Faust W. L.
Published: October 2006

In ionic crystals of the form M
+
X
-
, certain covalently bonded anion groups X
-
are particularly associated with instability. The heavier metal cations M
+
enhance this. Very sensitive explosives occur within the extended azide family, where X
-
= CNO
-
, N
3
-
, NCO
-
, or NCS
-
(an isoelectronic set of unsaturated linear triatomic anions). Another such family are the globular oxyanions X
-
= ClO
2
-
, ClO
3
-
, ClO
4
-
, NO
3
-
, and MnO
4
-
. Mishandling of NH
4
NO
3
or NH
4
ClO
4
has caused major disasters. An irreversible cyclic mechanism is proposed for such decomposition, involving mechanoelectronic band-gap excitation and coalescence of X with X
-
. From an intracrystalline ion-molecule collision complex, the singly charged dianion X
2
-
, exothermic reactions proceed with high yield.
The Neptune System in Voyager's Afterglow
Authors: Kerr Richard A.
Published: October 2006

Any time the view of a planet leaps from a fuzzy dot accompanied by two pinpoints of light to the riveting details of swirling clouds, rings, cratered moonlets, and even individual dust particles, planetary science is going to be in for some upheaval. Voyager 2's encounter with Neptune was no exception. Something as seemingly innocuous as an hour or two shift in the new length of a Neptunian day is giving meteorologists and physicists fits. And Neptune's canted, complex magnetic field found by Voyager knocks into a cocked hat most ideas about why a similar field at Uranus was unique. But there were more reassuring discoveries as well. Here are samplings of both sorts of findings.
Aminoacylation of Synthetic DNAs Corresponding to
Escherichia coli
Phenylalanine and Lysine tRNAs
Authors: Khan Akbar S. , Roe Bruce A.
Published: October 2006

Synthetic DNA oligomers (tDNAs) corresponding to
Escherichia coli
tRNA
Phe
or tRNA
Lys
have been synthesized with either deoxythymidine (dT) or deoxyuridine (dU) substituted in the positions occupied by ribouridine or its derivatives. The tDNAs inhibited the aminoacylation of their respective tRNAs with their cognate amino acids, but not the aminoacylation of tRNA
Leu
with Leu. In the presence of aminoacyl-tRNA synthetase, species of both a tDNA
Phe
synthesized with a 3′ terminal riboadenosine and a tDNA
Lys
containing only deoxynucleotides could be aminoacylated with the appropriate amino acids, although the Michaelis constant
K
m
and observed maximal rate
V
max
values for aminoacylation were increased by three- to fourfold and decreased by two- to threefold, respectively. The aminoacylation of synthetic tDNAs demonstrates that the ribose backbone of a tRNA is not absolutely required for tRNA aminoacylation.
Dispelling Myths About Verification of Sea-Launched Cruise Missiles
Authors: Lewis George N. , Ride Sally K. , Townsend John S.
Published: October 2006

It is widely believed that an arms control limit on nuclear-armed sea-launched cruise missiles would be nearly impossible to verify. Among the reasons usually given are: these weapons are small, built in nondistinctive industrial facilities, deployed on a variety of ships and submarines, and difficult to distinguish from their conventionally armed counterparts. In this article, it is argued that the covert production and deployment of nuclear-armed sea-launched cruise missiles would not be so straightforward. A specific arms control proposal is described, namely a total ban on nuclear-armed sea-launched cruise missiles. This proposal is used to illustrate how an effective verification scheme might be constructed.
Elimination of Current Dissipation in High Transition Temperature Superconductors
Authors: Sun J. Z. , Lairson B. , Eom C. B. , Bravman J. , Geballe T. H.
Published: October 2006

The relaxation of the shielding current-induced magnetic moment in YBa
2
Cu
3
O
7
thin films, which were grown in situ, is studied as a function of temperature. Although typical relaxations cause a large amount of decay in the magnetic shielding current (on the order of 10 to 20 percent for the first 1000 seconds), it is shown that this is not necessarily a serious problem for applications such as magnets operating in persistent-current modes. This is because the decay of the magnetic shielding current depends sensitively on how far away the operating current density is from the critical current density
J
c
. By using a quenching process the shielding current is reduced slightly below
J
c
and the relaxation is dramatically reduced. A general relation between the relaxation rate at
J
c
and the reduction of the relaxation rate upon lowering of the operating current is obtained and is shown to be consistent with experimental data.
Double-Stranded Ribonuclease Coinduced with Interferon
Authors: Meegan James M. , Marcus Philip I.
Published: October 2006

Double-stranded (ds) RNA and many viruses are inducers of interferon (IFN), the latter presumably because they contain, or can form, dsRNA. Concomitant with the induction of IFN in chicken embryo cells was the induction of a novel double-stranded ribonuclease (dsRNase), which was released into the medium and continued to accumulate long after IFN production ceased. Only avian cells (chicken, quail, turkey, or duck) expressed high levels of this dsRNase; mammalian, turtle, or fish cells did not. Production of the nuclease was inducer dose-dependent. Optimum
p
Hand cation requirements distinguished it from other dsRNase activities. Degradation of dsRNA was endonucleolytic. Activity resided in a molecule of an
M
r
of approximately 34,500. Low levels of a single-stranded (ss) RNase activity were inseparable from the dsRNase. The role for a dsRNA-inducible dsRNase released from cells is unknown.
Acetylcholine and GABA Mediate Opposing Actions on Neuronal Chloride Channels in Crayfish
Authors: Pfeiffer-Linn Cindy , Glantz Raymon M.
Published: October 2006

A central principle of neural integration is that excitatory and inhibitory neurotransmitters effect the opening of distinct classes of membrane ionic channels and that integration consists of the summation of the opposing ionic currents on the postsynaptic membrane. In tangential cells of crayfish optic lobes, a hyperpolarizing, biphasic synaptic potential is produced by the concurrent action of acetylcholine and γ-aminobutyric acid (GABA). Acetylcholine hyperpolarizes the cell and increases chloride conductance. GABA depolarizes the cell by closing some of the same chloride channels. Therefore, in this case integration is achieved by the antagonistic actions of two transmitters on the same ionic channel.
Growth and Erosion of Thin Solid Films
Authors: Bales G. Steven , Bruinsma Robijn , Eklund Elliott A. , Karunasiri R. P. U. , Rudnick Joseph , Zangwill Andrew
Published: October 2006

Thin films that are grown by the process of sputtering are, by and large, quite unlike the smooth, featureless structures that one might expect. In general, these films have a complicated surface morphology and an extended network of grooves and voids in their interiors. Such features can have a profound effect on the physical properties of a thin film. The surface irregularities and the bulk defects are the result of a growth instability due to competitive shadowing, an effect that also plays a role in geological processes such as erosion. For amorphous thin films, the shadow instability can be described by a remarkably simple model, which can be shown to reproduce many important observed characteristics of thin film morphology.
Forecasting Damaging Earthquakes in the Central and Eastern United States
Authors: Nishenko S. P. , Bollinger G. A.
Published: October 2006

Analysis of seismograph network data, earthquake catalogs from 1727 to 1982, and paleoseismic data for the central and eastern United States indicate that the Poisson probability of a damaging earthquake (magnitude ≥ 6.0) occurring during the next 30 years is at a moderate to high level (0.4 to 0.6). When differences in seismic wave attenuation are taken into account, the central and eastern United States has approximately two-thirds the likelihood of California to produce an earthquake with comparable damage area and societal impact within the next 30 years.
The Central Galaxy in Abell 2029: An Old Supergiant
Authors: Uson Juan M. , Boughn Stephen P. , Kuhn Jeffrey R.
Published: October 2006

A mosaic of images shows the extended structure of the cD galaxy that resides at the center of the rich cluster of galaxies Abell 2029. After correcting for the scattered light of nearby stars and galaxies, the faint halo of this giant can be traced out to a distance of more than 1 megaparsec, making it one of the largest and most luminous galaxies known. The smoothness of this halo suggests that it was formed early in the history of the cluster.
Structure of the Reduced TiO
2
(110) Surface Determined by Scanning Tunneling Microscopy
Authors: Rohrer Gregory S. , Henrich Victor E. , Bonnell Dawn A.
Published: October 2006

The scanning tunneling microscope has been used to image a reduced TiO
2
(110) surface in ultrahigh vacuum. Structural units with periodicities ranging from 21 to 3.4 angstroms have been clearly imaged, demonstrating that atomic resolution imaging of an ionic, wide band gap (3.2 electron volts) semiconductor is possible. The observed surface structures can be explained by a model involving ordered arrangements of two-dimensional defects known as crystallographic shear planes and indicate that the topography of nonstoichiometric oxide surfaces can be complex.
Balance of Risks and Benefits in Preparation for Earthquakes
Authors: Bolt Bruce A.
Published: October 2006

Widespread proposals to benefit from lessons of the 17 October 1989 (Loma Prieta) earthquake dramatize the difficulties associated with reducing seismic risk. There are three main problems. First, the understanding of earthquake generation is far from complete. For example, the unanticipated source style of this earthquake raises vital questions; claims of predicting its occurrence are weak, and, for practical reasons, the detailed pattern of damaging strong ground shaking was not predicted. Second, although their interactions are not well understood, competing social forces continue to prevent the optimum growth and application of knowledge for earthquake hazard mitigation. Third, the recent use of the probabilities of seismic risk has had mixed results. Because of indecision between minimizing loss of life and maximizing broader benefits, general agreement on acceptable earthquake risk remains confused.
Hydrodynamic Facilitation of Gregarious Settlement of a Reef-Building Tube Worm
Authors: Pawlik Joseph R. , Butman Cheryl Ann , Starczak Victoria R.
Published: October 2006

Experiments testing the effects of hydrodynamic processes and chemical cues on substrate selection were conducted with larvae of the marine tube worm
Phragmatopoma lapidosa californica
. In flume experiments, larvae were presented an array of sand treatments, including two substrates previously shown to induce metamorphosis in this species, under fast and slow flow regimes. Larvae preferentially metamorphosed on the inductive substrates in both flows. Delivery to the array was higher in fast flow because larvae tumbled along the bottom, whereas in slow flow, larvae were observed swimming in the water column. Thus, in addition to chemical cues, behavioral responses to flow conditions may play an important role in larval recruitment to the benthos.
Expression and Characterization of a Functional Myosin Head Fragment in
Dictyostelium discoideum
Authors: Manstein Dietmar J. , Ruppel Kathleen M. , Spudich James A.
Published: October 2006

The isolated head fragment of myosin is a motor protein that is able to use energy liberated from the hydrolysis of adenosine triphosphate to cause sliding movement of actin filaments. Expression of a myosin fragment nearly equivalent to the amino-terminal globular head domain, generally referred to as subfragment 1, has been achieved by transforming the eukaryotic organism
Dictyostelium discoideum
with a plasmid that carries a 2.6-kilobase fragment of the cloned
Dictyostelium
myosin heavy chain gene under the control of the
Dictyostelium
actin-15 promoter. The recombinant fragment of the myosin heavy chain was purified 2400-fold from one of the resulting cell lines and was found to be functional by the following criteria: the myosin head fragment copurified with the essential and regulatory myosin light chains, decorated actin filaments, and displayed actin-activated adenosine triphosphatase activity. In addition, motility assays in vitro showed that the recombinant myosin fragment is capable of supporting sliding movement of actin filaments.
U.S.-Japanese Space Relations at a Crossroads
Authors: Logsdon John M.
Published: October 2006

The relations between Japan and the United States in space form a microcosm of the complex, multidimensional interactions between these two powerful societies. Cooperation and competition exist side by side, and the future balance between them is uncertain. The United States needs to develop a strategy with respect to future U.S.-Japanese space relations that balances national security, political, scientific, and economic interests. Crafting such a strategy is particularly difficult while both the United States and Japan debate the goals and content of their future space programs and while the two nations try to assess their broader interests and roles in the rapidly changing geopolitical environment. Essential to a productive approach to U.S.-Japanese space relations is an accurate understanding of the character and content of the Japanese space effort.
Reaction Planning: Computer-Aided Discovery of a Novel Elimination Reaction
Authors: Herges Rainer , Hoock Christoph
Published: October 2006

Algorithms based on graph theory and implemented in a computer program have been used to search for unprecedented reactions. This approach is illustrated by a systematic and exhaustive screening of pericyclic reactions in order to find new reactions useful in the synthesis of conjugated dienes. Two reactions were found. They were optimized by structural variation with the aid of quantum-chemical calculations and were then experimentally verified.
The Effect of Surface Roughness on Triton's Volatile Distribution
Authors: Yelle Roger V.
Published: October 2006

Calculations of radiative equilibrium temperatures on Triton's rough surface suggest that significant condensation of N
2
may be occurring in the northern equatorial regions, despite their relatively dark appearance. The bright frost is not apparent in the Voyager images because it tends to be concentrated in relatively unilluminated facets of the surface. This patchwork of bright frost-covered regions and darker bare ground may be distributed on scales smaller than that of the Voyager resolution; as a result the northern equatorial regions may appear relatively dark. This hypothesis also accounts for the observed wind direction in the southern hemisphere because it implies that the equatorial regions are warmer than the south polar regions.
Geophysicists Take a Tour Around the Solar System
Authors: Kerr Richard A.
Published: October 2006

Never one to take its middle name too literally, the American Geophysical Union indulged the interests of a range of extraterrestrial researchers at its spring meeting last month in Montreal. In a session on the big icy bodies of the outer solar system, attendees saw the first view of the face of Pluto. In another session, on dating small rock samples, listeners heard evidence that the moon might have been battered in its youth. And a session ostensibly devoted to Earth's mantle yielded news that some form of plate tectonics seems to be operating on Venus.
Strand-Specific Recognition of a Synthetic DNA Replication Fork by the SV40 Large Tumor Antigen
Authors: SenGupta Dhruba J. , Borowiec James A.
Published: October 2006

The mechanism by which DNA helicases unwind DNA was tested; an "unwinding complex" between the SV40 large tumor antigen (T antigen) and a DNA molecule designed to resemble a replication fork was probed. In an adenosine triphosphate (ATP)—dependent reaction, T antigen quantitatively recognized this synthetic replication fork and bound the DNA primarily as a hexamer. The T antigen bound only one of the two strands at the fork, an asymmetric interaction consistent with the 3′ → 5′ directionality of the DNA helicase activity of T antigen. Binding to chemically modified DNA substrates indicated that the DNA helicase recognized the DNA primarily through the sugar-phosphate backbone. Ethylation of six top strand phosphates at the junction of single-stranded and double-stranded DNA inhibited the DNA helicase activity of T antigen. Neither a 3′ single-stranded end on the DNA substrate nor ATP hydrolysis was required for T antigen to bind the replication fork. These data suggest that T antigen can directly bind the replication fork through recognition of a fork-specific structure.
Expression of Myelin-Associated Glycoprotein by Small Neurons of the Dorsal Root Ganglion in Chickens
Authors: Omlin François Xavier , Matthieu Jean-Marie , Philippe Eric , Roch Jean-Marc , Droz Bernard
Published: October 2006

Biochemical and immunocytochemical investigations have shown that myelin-associated glycoprotein (MAG) is exclusively related to myelin and myelin-forming cells in mammals. In the present study it was found that dorsal root ganglia in young chickens display MAG-immunoreactive material in most small sensory neurons. The presence of MAG at the surface of small sensory neurons raises the question of whether this glycoprotein acts as a cell adhesion molecule in lower vertebrates.
Chemists Cluster in Chicago to Confer on Cagey Compounds
Authors: Moffat Anne Simon
Published: October 2006

Shrink a clump of matter to a few hundred atoms, and it enters a curious netherworld. Neither ordinary solids nor conventional small molecules, such atomic clusters have unique chemical, optical, and electronic properties. Since the mid-1970s, when advances in synthesizing and analyzing clusters first enabled researchers to explore this netherworld in earnest, clusters have nucleated a sizable field. Many of its participants gathered in Chicago on 15 to 22 September for the Sixth International Symposium on Small Particles and Inorganic Clusters, the first of the series to be held in the United States. At the top of the agenda for the 300 attendees were the field's old stalwarts, various kinds of metal clusters; its current darlings, the carbon clusters known as fullerenes; and a possible future superstar, silicon clusters.
The Age and Size of the Universe
Authors: van den Bergh Sidney
Published: October 2006

Modern distance determinations to galaxies were reviewed and placed on a uniform and self-consistent scale. Based on eight separate but not entirely independent techniques, the distance to the Virgo cluster was found to be 15.8 ± 1.1 megaparsec. Twelve different determinations yield a Coma/Virgo distance ratio of 5.52 ± 0.13 and hence a Coma distance of 87 ± 6 megaparsec. With a cosmological redshift of 7210 kilometers per second, this gives a Hubble parameter
H
0
(local) of 83 ± 6 kilometers per second per megaparsec. From the velocity-distance relation of rich clusters of galaxies, the ratio of the value of
H
0
(global) to the value of
H
0
(local) was determined to be 0.92 ± 0.08. In other words, the cluster data do not show a statistically significant difference between the local and global values of the Hubble parameter. If one nevertheless adopts this relation between
H
0
(global) and
H
0
(local), then the value of
H
0
(global) is 76 ± 9 kilometers per second per megaparsec. This observed value differs at the ∼3σ level (where σ is the standard deviation of the distribution) from values in the range 36 ≲
H
0
≲ 50 kilometers per second per megaparsec, which are derived from stellar evolutionary theory in conjunction with standard cosmological models with a density parameter (ω) that is equal to 1 and a cosmological constant (λ) that is equal to 0.
Scanning Tunneling Microscopy of Electrodeposited Ceramic Superlattices
Authors: Switzer Jay A. , Raffaelle Ryne P. , Phillips Richard J. , Hung Chen-Jen , Golden Teresa D.
Published: October 2006

Cleaved cross sections of nanometer-scale ceramic superlattices fabricated from materials of the lead-thallium-oxygen system were imaged in the scanning tunneling microscope (STM). The apparent height differences between the layers were attributed to composition-dependent variations in local electrical properties. For a typical superlattice, the measured modulation wavelength was 10.6 nanometers by STM and 10.8 nanometers by x-ray diffraction. The apparent height profile for potentiostatically deposited superlattices was more square than that for galvanostatically deposited samples. These results suggest that the composition follows the applied potential more closely than it follows the applied current. The x-ray diffraction pattern of a superlattice produced under potential control had satellites out to the fourth order around the (420) Bragg reflection.
Predators, Prey, and Natural Disasters Attract Ecologists
Authors: Mlot Christine , Moffat Anne Simon
Published: October 2006

Some 2200 ecologists turned out for the 78th annual meeting of the Ecological Society of America (ESA), held in Madison, Wisconsin, 31 July to 4 August. Among the offerings: reports on the effect of dams and levees on large river ecology, predator-prey interactions, how parasites might control evolution, and the impact of clearcutting on soil organisms.
A Quasi-Biennial Oscillation Signal in General Circulation Model Simulations
Authors: Cariolle D. , Amodei M. , Déqué M. , Mahfouf J. -F. , Simon P. , Teyssédre H.
Published: October 2006

The quasi-biennial oscillation (QBO) is a free atmospheric mode that affects the equatorial lower stratosphere. With a quasi-regular frequency, the mean equatorial zonal wind alternates from easterly to westerly regimes. This oscillation is zonally symmetric about the equator, has its largest amplitude in the latitudinal band from 20°S to 20°N, and has a mean period of about 27 months. The QBO appears to originate in the momentum deposition produced by the damping in the stratosphere of equatorial waves excited by diabatic thermal processes in the troposphere. The results of three 10-year simulations obtained with three general circulation models are reported, all of which show the development in the stratosphere of a QBO signal with a period and a spatial propagating structure that are in good agreement with observations without any ad hoc parameterization of equatorial wave forcing. Although the amplitude of the oscillation in the simulations is still less than the observed value, the result is promising for the development of global climate models.
A Yeast Actin-Binding Protein Is Encoded by
SAC6
, a Gene Found by Suppression of an Actin Mutation
Authors: Adams Alison E. M. , Botstein David , Drubin David G.
Published: October 2006

The protein encoded by
SAC6
, a gene that can mutate to suppress a temperature-sensitive defect in the yeast actin gene, has been identified as a 67-kilodalton actin-binding protein (ABP 67) that associates with all identifiable actin structures. This finding demonstrates the in vivo functional importance of the actin-ABP 67 interaction previously established in vitro and illustrates the use of suppressor analysis to identify physically interacting proteins.
Scanning Tunneling Microscopy of Freeze-Fracture Replicas of Biomembranes
Authors: Zasadzinski Joseph A. N. , Schneir Jason , Gurley John , Elings Virgil , Hansma Paul K.
Published: October 2006

The high resolution of the scanning tunneling microscope (STM) makes it a potentially important tool for the study of biomaterials. Biological materials can be imaged with the STM by a procedure in which fluid, nonconductive biomaterials are replaced by rigid and highly conductive freeze-fracture replicas. The three-dimensional contours of the ripple phase of dimyristoylphosphatidylcholine bilayers were imaged with unprecedented resolution with commercial STMs and standard freeze-fracture techniques. Details of the ripple amplitude, asymmetry, and configuration unobtainable by electron microscopy or x-ray diffraction can be observed relatively easily with the STM.
Expression of the Multidrug-Resistant Gene in Hepatocarcinogenesis and Regenerating Rat Liver
Authors: Thorgeirsson S. S. , Huber B. E. , Sorrell S. , Fojo A. , Pastan I. , Gottesman M. M.
Published: October 2006

Preneoplastic and neoplastic liver nodules and hepatocytes isolated from regenerating rat liver have been shown to be resistant to a broad range of carcinogenic agents. This phenomenon was studied by measuring the expression of the multidrug-resistant (
mdr
) gene in normal liver cells and in preneoplastic and neoplastic nodules and regenerating liver. Levels of messenger RNA for the
mdr
gene, which encodes P-glycoprotein, were elevated in both preneoplastic and neoplastic lesions. Expression of the
mdr
gene also reached high levels in regenerating rat liver 24 to 72 hours after partial hepatectomy. These results show that the expression of the
mdr
gene can be regulated in liver and is likely to be responsible for part of the multidrug-resistance phenotype of carcinogen-initiated hepatocytes and regenerating liver cells.
Identification of a Novel Thyroid Hormone Receptor Expressed in the Mammalian Central Nervous System
Authors: Thompson Catherine C. , Weinberger Cary , Lebo Roger , Evans Ronald M.
Published: October 2006

A complementary DNA clone derived from rat brain messenger RNA has been isolated on the basis of homology to the human thyroid hormone receptor gene. Expression of this complementary DNA produces a high-affinity binding protein for thyroid hormones. Sequence analysis and the mapping of this gene to a distinct human genetic locus indicate the existence of multiple human thyroid hormone receptors. Messenger RNA from this gene is expressed in a tissue-specific fashion with highest levels in the central nervous system.
Anti-Idiotypic Antibodies Bear the Internal Image of a Human Tumor Antigen
Authors: Herlyn Dorothee , Ross Alonzo H. , Koprowski Hilary
Published: October 2006

Goat antibodies to idiotypes (anti-idiotypic antibodies; Ab2) that recognize an idiotype associated with the combining site of a BALB/c mouse IgG2a monoclonal antibody (Ab1) to human gastric carcinoma were used to immunize BALB/c mice and rabbits. A monoclonal anti-anti-idiotypic antibody (Ab3) of IgG1 isotype was obtained after immunization of mice. The Ab3 and the Ab1 showed identical binding specificities and bound with similar avidities to the same tumor antigen. The induction of Ab1-like Ab3 by Ab2 was not restricted to mice, since Ab3 could also be induced in rabbits. Both the mouse- and the rabbit-derived Ab3 bound the same gastrointestinal cancer-associated antigen as Ab1. These findings indicate that Ab2 induced the formation of antigen-specific Ab3, probably because it bears the internal image of the tumor-associated antigen. This Ab2 may therefore have potential for modulating the immune response of cancer patients to their tumors.
Regulation of Erythrocyte Cation and Water Content in Sickle Cell Anemia
Authors: Brugnara Carlo , Bunn H. Franklin , Tosteson Daniel C.
Published: October 2006

The pathophysiological events in sickle cell disease are critically dependent on the intracellular concentration of hemoglobin S, which varies inversely with cell cation and water content. Erythrocytes of SS homozygotes exposed to oxygen or carbon monoxide decrease their potassium and water content through a pathway for potassium transport that is activated by both cell swelling and decrease in internal
p
H. This pathway is not inhibited by ouabain either with or without bumetanide. When SS erythrocytes were separated according to density, the
p
H- and volume-dependent potassium transport was greatest in the least dense fraction and was reduced in the densest cells. This pathway, which does not depend on polymerization of sickle hemoglobin, may be important in regulating the cation and water content of SS erythrocytes.
Microwave Radiation and Chlordiazepoxide: Synergistic Effects on Fixed-Interval Behavior
Authors: Thomas John R. , Burch Linda S. , Yeandle Stephen S.
Published: October 2006

In the presence of low-intensity pulsed microwave radiation, at an average power density of 1 milliwatt per square centimeter, the response-rate-increasing effects of chlordiazepoxide were potentiated in rats. The behavioral effects of a drug can be modified by brief exposure to a low-level microwave field even when the radiation level alone has no apparent effects on the behavior.
Interaction of Brain Synaptic Vesicles Induced by Endogenous Ca
2+
-Dependent Phospholipase A
2
Authors: Moskowitz Nathan , Schook William , Puszkin Saul
Published: October 2006

Endogenous phospholipase A
2
activity of brain synaptic vesicles was Ca
2+
-dependent and was increased by prostaglandinF
2α
, calmodulin, adenosine 3′,5′ -monophosphate, and adenosine triphosphate, whereas the activity was inhibited by prostaglandin E
2
in the absence or presence of calmodulin. Light-scattering measurements demonstrated that stimulation of the enzyme's activity correlated with the induction of vesicle-vesicle aggregation. The effects of these compounds on endogenous synaptic vesicle phospholipase A
2
activity may imply a common end point of their purported neuromodulatory actions, and indicate that synaptic vesicle phospholipase A
2
may play a central role in presynaptic neurotransmission.
Reversal of Adriamycin Resistance by Verapamil in Human Ovarian Cancer
Authors: Rogan Alfred M. , Hamilton Thomas C. , Young Robert C. , Klecker Raymond W. , Ozols Robert F.
Published: October 2006

The effectiveness of adriamycin in the treatment of ovarian cancer and other human tumors has been limited by the development of drug resistance. Verapamil, a calcium channel blocking agent, completely reversed adriamycin resistance in human ovarian cancer cells with moderate (three- to sixfold) degrees of resistance and partially reversed resistance in highly (150-fold) resistant cells. The potentiating effect of verapamil was due to inhibition of adriamycin efflux in the resistant cells. These results have led to a clinical trial of adriamycin and verapamil in refractory ovarian cancer patients.
Desickling of Sickled Erythrocytes by Pulsed Radio-Frequency Field
Authors: Takashima Shiro , Asakura Toshio
Published: October 2006

Electric fields were found to deform sickled erythrocytes. When the intensity of applied fields exceeded a threshold value, sickled erythrocytes transformed into a spherical shape. Prolonged application of the field usually caused hemolysis of erythrocytes. Deformation of red blood cells could be partly reversed if the field was turned off at an early stage. The cause of desickling may be the interaction of the field with the erythrocyte membrane and also with gelled intracellular hemoglobin S molecules.
Larvae of Air-Breathing Fishes as Countercurrent Flow Devices in Hypoxic Environments
Authors: Liem Karel F.
Published: October 2006

Larvae of the air-breathing teleost fish
Monopterus
are frequently exposed to periods of critical hypoxia, which they can survive because they have (i) dense capillary networks in the skin, (ii) a small blood-water barrier, (iii) an active pectoral fin mechanism that generates a posteriorly directed respiratory water current originating from the oxygen-rich surface layer, and (iv) a principal flow of blood that runs countercurrent to the water stream. Experimental data show that the larva as a whole is a functional analog of a fish gill lamella and that similar adaptive mechanisms are present in larvae of ancient fishes and some modern teleosts inhabiting permanently or periodically hypoxic waters.
Blue-Green Algae: Their Excretion of Iron-Selective Chelators Enables Them to Dominate Other Algae
Authors: Murphy T. P. , Lean D. R. S. , Nalewajko C.
Published: October 2006

During blue-green algal blooms, other algae can be completely suppressed. This ability of blue-green algae to suppress other algae may be determined by the availability of iron. Iron deprivation induces the production of hydroxamate chelators, which appear to be the agent suppressing other algae.
Photoreceptor Mutant of
Drosophila
: Is Protein Involved in Intermediate Steps of Phototransduction?
Authors: Paj W. K. , Istrit S. E. , Deland M. C. , Wu C.-F.
Published: October 2006

In
norpA
mutants of Drosophila melanogaster the phototransduction process is either partially or completely blocked. By using a temperature-sensitive allele, we have found that the
norpA
mutation has little or no effect on either the rhodopsin-metarhodopsin transition or the machinery of quantum bump production. Thus, the
norpA
lesion appears to be localized in the intermediate process of phototransduction. Because a temperature-sensitive allele of
norpA
has been isolated, the
norpA
gene probably encodes a protein involved in the process.
Visual Pigment Changes in Rainbow Trout in Response to Temperature
Authors: Tsin Andrew T. C. , Beatty David D.
Published: October 2006

Lower water temperature (6°C in comparison to 16°C) favors a higher proportion of porphyropsin in the retina of rainbow trout (
Salmo gairdneri
), regardless of the light conditions (constant darkness or 12 hours of light and 12 of darkness). This response to temperature does not follow a Q
10
relation, namely an increase in the rate of a reaction produced by raising the temperature 10°C.
Adipose Tissue Regeneration Following Lipectomy
Authors: Faust Irving M. , Johnson Patricia R. , Hirsch Jules
Published: October 2006

Surgical removal of subcutaneous fat depots in weanling rats leads to a regenerative response. If the rats are fed a diet high in fat, adipose mass and adipocyte number are precisely restored within 7 months of surgery. Thus, under appropriate experimental circumstances, compensatory hyperplasia will occur in adipose tissues of the rat.
A common genetic variant in XPD associates with risk of 5q- and 7q-deleted acute myeloid leukemia
Authors: Smith Alexandra G. , Worrillow Lisa J. , Allan James M.
Published: October 2006

Numerous structural genetic abnormalities observed in acute myeloid leukemia (AML) illustrate the heterogeneity of this disease, which likely has contributed to difficulty in identifying susceptibility alleles for AML. We previously reported that carriers of the glutamine-encoding allele at codon 751 of the xeroderma pigmentosum group D (XPD) DNA repair gene were significantly more likely to have a karyotype associated with a less favorable prognosis, and hypothesized that this observation was driven by an association between the codon 751 variant and risk of developing AML with specific structural abnormalities. Using a case series of 927 patients with AML, we show here that the XPD codon 751 glutamine-encoding variant significantly associates with risk of developing AML with a chromosome 5q deletion (odds ratio [OR] 2.09; 95% confidence interval [CI] 1.14-3.81; n = 69; P = .02) or a chromosome 7q deletion (OR 2.27; 95% CI 1.09-4.71; n = 47; P = .03), but not with any other commonly recurring cytogenetic lesion.
The sternocleidomastoid myocutaneous flap
Authors: Ariyan Stephan
Published: October 2006

The sternocleidomastoid muscle has three blood supplies: the occipital artery superiorly, the superior thyroid in the middle, and the thyrocervical trunk inferiorly. A compound flap has been developed to transport segments of neck skin on either end of a pedicle of sternocleidomastoid muscle to reconstruct defects in the oral cavity or orophaynx. It permits one‐stage reconstruction at the time of the primary resection and eliminates the need for skin grafts to the donor sites.
Thermoplastic Acrylic Rubber Physically Crosslinked by Tiny Poly(vinylidene fluoride) Crystals
Authors: Li Yongjin , Oono Yuko , Nakayama Kazuo , Shimizu Hiroshi
Published: October 2006

Summary: Acrylic rubber showed greatly improved mechanical properties and very nice elasticity when blended with small amount of PVDF. PVDF crystallized into very sparse and loose spherulites in the blends with ACM molecular chains incorporated into the PVDF lamellae. These micro‐crystals were precisely dispersed in the ACM matrix and acted as the physical crosslink points for the matrix upon stretching. Therefore, the ACM/PVDF blends containing small amounts of PVDF display the typical properties of thermoplastic elastomers with large elongation at break, high tensile strength, and excellent strain recovery from the highly deformed state.

Schematic diagram of physically crosslinked ACM by the tiny PVDF crystals in ACM‐rich PVDF/ACM blends.

magnified image

Schematic diagram of physically crosslinked ACM by the tiny PVDF crystals in ACM‐rich PVDF/ACM blends.
Moments of truth in gift exchanges: A critical incident analysis of communication indicators used to detect gift failure
Authors: Roster Catherine A.
Published: October 2006

This research examines how gift recipients communicate gift failure to givers, whether through paralinguistic indicators, direct verbal comments, and consumption (or not) of the gift. Critical incident reports identified specific communication indicators that signaled displeasure with the gift and measured the impact of these indicators on important exchange outcomes. Overall, failed gifts have a greater impact on future exchanges than on relationship quality. However, failure to appreciate the gift can have a significant negative effect on relationships. Gift failures between friends, co‐workers, and in‐laws are more susceptible to relationship harm than those involving close kin, like parents, spouses, and children. © 2006 Wiley Periodicals, Inc.
Social influence: The role of self‐monitoring when making social comparisons
Authors: Harnish Richard J. , Bridges K. Robert
Published: October 2006

The self‐monitoring construct (Snyder, 1987) may prove to be useful when examining who individuals choose when making social comparisons. In Study 1, the self‐monitoring propensity of individuals who provide social comparison information and the self‐monitoring propensity of individuals who use such information were examined. Results supported the hypothesis that high self‐monitors have advisors (i.e., individuals to whom they first turn for advice) that are high in self‐monitoring, whereas low self‐monitors have advisors that are low in self‐monitoring. In Study 2, high and low self‐monitors identified their advisors as experts and generalists. Results supported the hypothesis that high self‐monitors have more expert advisors than low self‐monitors. The findings are discussed in terms of the implications for consumer decision making. © 2006 Wiley Periodicals, Inc.
International variations in the treatment and co‐morbidity of left ventricular systolic dysfunction: Data from the EuroHeart Failure Survey
Authors: Lainščak Mitja , Cleland John G.F. , Lenzen Mattie J. , Follath Ferenc , Komajda Michel , Swedberg Karl
Published: October 2006

Background:

Treatment of heart failure (HF) due to left ventricular systolic dysfunction (LVSD) is effective, but many patients are not treated in accordance with guidelines. This may reflect a lack of adequate organisation of care or co‐morbidity contra‐indicating therapy.

Aims:

To evaluate the effect of co‐morbidities on the prescription of neurohormonal antagonists for HF.

Methods and results:

The EuroHeart Failure Survey identified 10,701 patients with suspected or confirmed HF during 2000 and 2001, 64% of whom had an imaging test and 3658 had documented LVSD. This last group constitutes the focus of this report. Renal dysfunction was associated with lower prescription of ACE inhibitors at discharge (74% vs. 83%, p<0.001). Beta‐blockers were less often used in patients with respiratory disease (32% vs. 53%, p<0.001). Co‐morbidity did not appear to affect the use of spironolactone. There were few important international differences in uptake of key therapies amongst European countries with widely differing cultures and economic status.

Conclusions:

Guidelines appear successful in creating a relatively uniform approach to the treatment for HF due to LVSD in diverse medical cultures. Relevant co‐morbidity seems to be responsible for a substantial reduction in the prescription of ACE inhibitors and beta‐blockers. However, whilst co‐morbidity indicates the need for greater caution, it is often not a valid contra‐indication to life‐saving therapy.