bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Sympathetic Stimulation on Various Repolarization Indices in the Congenital Long QT Syndrome
Authors: Shimizu Wataru
Published: October 2006

Abstract Sympathetic stimulation or catecholamines modulate ventricular repolarization and provoke ventricular tachyarrhythmias in a variety of heart diseases and conditions. Among those, the congenital form of long QT syndrome (LQTS) has long been known to be a Rosetta stone for sympathetic‐related ventricular tachyarrhythmias. Recent experimental studies employing arterially‐perfused ventricular wedge preparations as well as some clinical studies have greatly advanced our knowledge of the cellular mechanism of the T wave and the various repolarization indices in the ECG, as well as the effect of sympathetic stimulation on these repolarization indices under normal and long QT conditions. Differences in the time course of repolarization of the three predominant cell types, the epicardial, midmyocardial (M), and endocardial cells, across the ventricular wall give rise to voltage gradients responsible for the inscription of normal T waves as well as the manifestation of abnormal T waves in the congenital LQTS. The data from the wedge experiments suggest that the repolarization time of the longest M cell action potential determines the Q‐Tend interval, while that of the epicardial action potential determines the Q‐Tpeak interval. Therefore, Tpeak‐end interval in the ECG may provide an index of transmural dispersion of repolarization (TDR). In this review article, sympathetic stimulation with isoproterenol or epinephrine infusion is demonstrated to modulate differentially these repolarization indices in the ECG as well as the action potentials of the three cells between the LQT1, LQT2, and LQT3 syndromes both experimentally and clinically, explaining the differences in the sensitivity of genotypes of congenital LQTS to sympathetic stimulation. A.N.E. 2002;7(4):332‐‐342
Structural and Dielectric Characteristics of Barium Lanthanum Zinc Niobate
Authors: Lee Chun‐Te , Lin Yi‐Chang , Huang Chi‐Yuen , Su Che‐Yi , Hu Chin‐Li
Published: October 2006

The dielectric properties and microstructural characteristics in solid solutions of Ba1−xLax[Zn(1+x)/3Nb(2−x)/3]O3 (BLZN) are investigated by measuring and observing these properties, respectively, by means of transmission electron microscopy and Raman spectroscopy. The 1:1 ordered structure of BLZN can be explained by the random‐site model for the distribution of B‐site cations. The decrease in the tolerance factor (t) by lanthanum substitution causes the tilting of oxygen octahedra. It appears that the onset of antiphase and inphase tilting causes the variation in the temperature coefficient of resonant frequency (τf). In the untilted region where t≥1.01, the τf shows a linear increase with decreasing tolerance factor. The region of antiphase tilting, where 0.965≤t<1.01, causes a rapid decrease in τf, including the reverse sign. The τf slowly increases, where t<0.965, which is due to the presence of inphase tilting of oxygen octahedra. The τf can be predicted by using the tolerance factor, and the near zero of τf can be obtained with lanthanum substitution in the solid solution of the BLZN system.
Conservative sorting in a primitive plastid
Authors: Steiner Juergen M. , Berghöfer Juergen , Yusa Fumie , Pompe Johannes A. , Klösgen Ralf B. , Löffelhardt Wolfgang
Published: October 2006

Higher plant chloroplasts possess at least four different pathways for protein translocation across and protein integration into the thylakoid membranes. It is of interest with respect to plastid evolution, which pathways have been retained as a relic from the cyanobacterial ancestor (‘conservative sorting’), which ones have been kept but modified, and which ones were developed at the organelle stage, i.e. are eukaryotic achievements as (largely) the Toc and Tic translocons for envelope import of cytosolic precursor proteins. In the absence of data on cyanobacterial protein translocation, the cyanelles of the glaucocystophyte alga Cyanophora paradoxa for which in vitro systems for protein import and intraorganellar sorting were elaborated can serve as a model: the cyanelles are surrounded by a peptidoglycan wall, their thylakoids are covered with phycobilisomes and the composition of their oxygen‐evolving complex is another feature shared with cyanobacteria. We demonstrate the operation of the Sec and Tat pathways in cyanelles and show for the first time in vitro protein import across cyanobacteria‐like thylakoid membranes and protease protection of the mature protein.
The first stars in the Universe
Authors: Naoz S. , Noter S. , Barkana R.
Published: October 2006

Large telescopes have allowed astronomers to observe galaxies that formed as early as 850 million years after the big bang. We predict when the first star that astronomers can observe (i.e. in our past light cone) formed in the Universe, accounting for the first time for the size of the Universe and for three essential ingredients: the light travel-time from distant galaxies, Poisson and density fluctuations on all scales, and the effect of very early cosmic history on galaxy formation. We find that the first observable star is most likely to have formed 30 million years after the big bang (at redshift 65). Also, the first galaxy as massive as our own Milky Way likely formed when the Universe was only 400 Myr old (at redshift 11). We also show that significant modifications are required in current methods of numerically simulating the formation of galaxies at redshift 20 and above.
From Exotics to Brainwashers: Portraying New Religions in Mass Media
Authors: McCloud Sean
Published: October 2006

This essay examines how American magazines have portrayed new religions since the World War II. Media depictions have changed dramatically from the 1950s to the present. Specifically, journalists in the 1950s and early 1960s used the dual Cold War themes of exoticism and subversion to depict new religions. In the late 1960s and early 1970s, subjects and themes began to change. Newsmagazines ambivalently reported on the gurus, Asian new religions, and occult spirituality attracting some in the burgeoning youth counterculture with a mixture of exoticism and wariness. By the mid‐1970s, media images became more ominous. News, general interest, and entertainment media represented new religions as a growing “cult menace” and highlighted the dangers that brainwashing groups posed to unsuspecting followers. The 1978 Jonestown mass suicide seemed to confirm such negative cult stereotypes, leading to homogenous portrayals of new religions that continued through the 1990s. In explaining such changes over time, the essay ends by proposing five complimentary theses for understanding late‐twentieth‐century mass media representations of new religions.
Jews and Judaism in Dixie
Authors: Bauman Mark K.
Published: October 2006

This article advocates the integration of Southern Jewish history into the mainstream study of Southern and American history and religion. It argues that such integration provides greater breadth and depth to those fields as well as a fruitful model for comparison and contrast. This article also provides reference to some of the necessary resources to scholars in other fields and brings the readers’ attention especially to a new publication for that purpose: Dixie Diaspora: An Anthology of Southern Jewish History.
Permian-Triassic Life Crisis on Land
Authors: Retallack G. J.
Published: October 2006

Recent advances in radiometric dating and isotopic stratigraphy have resulted in a different placement of the Permian-Triassic boundary within the sedimentary sequence of the Sydney Basin of southeastern Australia. This boundary at 251 million years ago was a time of abrupt decline in both diversity and provincialism of floras in southeastern Australia and extinction of the
Glossopteris
flora. Early Triassic vegetation was low in diversity and dominated by lycopods and voltzialean conifers. The seed fern
Dicroidium
appeared in the wake of Permian-Triassic boundary floral reorganization, but floras dominated by
Dicroidium
did not attain Permian levels of diversity and provinciality until the Middle Triassic (244 million years ago).
Visualization of Surfactants on Nanostructured Palladium Clusters by a Combination of STM and High-Resolution TEM
Authors: Reetz Manfred T. , Helbig Wolfgang , Quaiser Stefan A. , Stimming Ulrich , Breuer Norbert , Vogel Roland
Published: October 2006

Scanning tunneling microscopy (STM) and high-resolution transmission electron microscopy (TEM) have been used to determine the dimensions of a series of palladium clusters stabilized by tetraalkylammonium salts. Electrochemically prepared colloids were used in which the average diameter of the inner metal core was varied between 2 and 4 nanometers, and the size of the ammonium ions was adjusted in the series
+
N(
n
-C
4
H
9
)
4
<
+
N(
n
-C
8
H
17
)
4
<
+
N(
n
-C
18
H
37
)
4
. The difference between the mean diameter determined by STM and that measured by TEM allows the determination of the thickness of the protective surfactant layer. On the basis of these studies, a model of the geometric properties of ammonium-stabilized palladium clusters has been proposed. Suggestions for the mechanism of the STM imaging process are also made.
Interhemispheric Differences in Polar Stratospheric HNO
3
, H
2
O, ClO, and O
3
Authors: Santee M. L. , Read W. G. , Waters J. W. , Froidevaux L. , Manney G. L. , Flower D. A. , Jarnot R. F. , Harwood R. S. , Peckham G. E.
Published: October 2006

Simultaneous global measurements of nitric acid (HNO
3
), water (H
2
O), chlorine monoxide (ClO), and ozone (O
3
) in the stratosphere have been obtained over complete annual cycles in both hemispheres by the Microwave Limb Sounder on the Upper Atmosphere Research Satellite. A sizeable decrease in gas-phase HNO
3
was evident in the lower stratospheric vortex over Antarctica by early June 1992, followed by a significant reduction in gas-phase H
2
O after mid-July. By mid-August, near the time of peak ClO, abundances of gas-phase HNO
3
and H
2
O were extremely low. The concentrations of HNO
3
and H
2
O over Antarctica remained depressed into November, well after temperatures in the lower stratosphere had risen above the evaporation threshold for polar stratospheric clouds, implying that denitrification and dehydration had occurred. No large decreases in either gas-phase HNO
3
or H
2
O were observed in the 1992-1993 Arctic winter vortex. Although ClO was enhanced over the Arctic as it was over the Antarctic, Arctic O
3
depletion was substantially smaller than that over Antarctica. A major factor currently limiting the formation of an Arctic ozone "hole" is the lack of denitrification in the northern polar vortex, but future cooling of the lower stratosphere could lead to more intense denitrification and consequently larger losses of Arctic ozone.
Synthesis and Characterization of Anisometric Cobalt Nanoclusters
Authors: Gibson Charles P. , Putzer Kathy J.
Published: October 2006

Sonication of aqueous Co
2+
and hydrazine resulted in the formation of anisometric (disk-shaped) cobalt nanoclusters that averaged about 100 nanometers in width and 15 nanometers in thickness. Electron diffraction from single particles revealed that they were oriented (001) crystals that conformed to a trigonal or hexagonal unit cell four times the size of the cell adopted by bulk α-cobalt. Lorentz microscopy indicated that these were single-magnetic domain particles, with the axis of magnetization located in the (101) plane, offset at some appreciable angle from the 〈001〉 axis.
Kinetics of Conversion of Air Bubbles to Air Hydrate Crystals in Antarctic Ice
Authors: Price P. B.
Published: October 2006

The depth dependence of bubble concentration at pressures above the transition to the air hydrate phase and the optical scattering length due to bubbles in deep ice at the South Pole are modeled with diffusion-growth data from the laboratory, taking into account the dependence of age and temperature on depth in the ice. The model fits the available data on bubbles in cores from Vostok and Byrd and on scattering length in deep ice at the South Pole. It explains why bubbles and air hydrate crystals coexist in deep ice over a range of depths as great as 800 meters and predicts that at depths below ∼1400 meters the AMANDA neutrino observatory at the South Pole will operate unimpaired by light scattering from bubbles.
Physical Aging in Polymer Glasses
Authors: Hodge Ian M.
Published: October 2006

Physical aging refers to structural relaxation of the glassy state toward the metastable equilibrium amorphous state, and it is accompanied by changes in almost all physical properties. These changes, which must be taken into account in the design, manufacture, and use of glassy polymer materials and devices, present a daunting challenge to theorists.
Chemists Self-Assemble in Southern California
Authors: Service Robert F.
Published: October 2006

ANAHEIM, CALIFORNIA—Nearly 10,000 scientists gathered for the 209th national meeting of the American Chemical Society (ACS), held from 2 to 6 April. One piece of unwelcome news was that the ACS governance boards approved hikes in journal subscription prices for 1996. But researchers considered matters more physical than fiscal, listening to presentations on substances that self-construct, molecules that clean up after themselves, and DNA recovered from a stone, among other topics.
Efficient Oxidative Dechlorination and Aromatic Ring Cleavage of Chlorinated Phenols Catalyzed by Iron Sulfophthalocyanine
Authors: Sorokin Alexander , Meunier Bernard , Séris Jean-Louis
Published: October 2006

An efficient method has been developed for the catalytic oxidation of pollutants that are not easily degraded. The products of the hydrogen peroxide (H
2
O
2
) oxidation of 2,4,6-trichlorophenol (TCP) catalyzed by the iron complex 2,9,16,23-tetrasulfophthalocyanine (FePcS) were observed to be chloromaleic, chlorofumaric, maleic, and fumaric acids from dechlorination and aromatic cycle cleavage, as well as additional products that resulted from oxidative coupling. Quantitative analysis of the TCP oxidation reaction revealed that up to two chloride ions were released per TCP molecule. This chemical system, consisting of an environmentally safe oxidant (H
2
O
2
) and an easily accessible catalyst (FePcS), can perform several key steps in the oxidative mineralization of TCP, a paradigm of recalcitrant pollutants.
Plant Growth-Rate Dependence of Detrital Carbon Storage in Ecosystems
Authors: Cebrián Just , Duarte Carlos M.
Published: October 2006

Detrital carbon accumulation accounts for most of an ecosystem's capacity to store organic carbon because the carbon contained as plant detritus exceeds that stored in living plants by about threefold. A comparative analysis of the mass and turnover of detrital carbon in ecosystems demonstrates that these properties are strongly related to the turnover rate of the dominant primary producers and are poorly related to ecosystem primary production. These results contribute to an understanding of the factors that control carbon storage in ecosystems and the role of carbon storage in the global carbon budget.
High-Temperature Phase Transition and Dissociation of (Mg, Fe)SiO
3
Perovskite at Lower Mantle Pressures
Authors: Meade Charles , Mao Ho Kwang , Hu Jingzhu
Published: October 2006

To study the crystallography of Earth's lower mantle, techniques for measuring synchrotron x-ray diffraction from a laser-heated diamond anvil cell have been developed. Experiments on samples of (Mg, Fe)SiO
3
show that silicate perovskite maintains its orthorhombic symmetry at 38 gigapascals and 1850 kelvin. Measurements at 65 and 70 gigapascals provide evidence for a temperature-induced orthorhombic-to-cubic phase transition and dissociation to an assemblage of perovskite and mixed oxides. If these phase transitions occur in Earth, they will require a significant change in mineralogical models of the lower mantle.
High Concentrations of Toxaphene in Fishes from a Subarctic Lake
Authors: Kidd Karen A. , Schindler David W. , Muir Derek C. G. , Lockhart W. Lyle , Hesslein Raymond H.
Published: October 2006

Concentrations of toxaphene and other organochlorine compounds are high in fishes from subarctic Lake Laberge, Yukon Territory, Canada. Nitrogen isotope analyses of food chains and contaminant analyses of biota, water, and dated lake sediments show that the high concentrations of toxaphene in fishes from Laberge resulted entirely from the biomagnification of atmospheric inputs. A combination of low inputs of toxaphene from the atmosphere and transfer through an exceptionally long food chain has resulted in concentrations of toxaphene in fishes that are considered hazardous to human health.
Young Scientists Voice Hopes and Fears for the Future
Authors: Holden Constance
Published: October 2006

The fast-approaching 21st century is filled with both promise and anxiety for budding scientists: the promise of exciting research, and anxiety about having no job in which to do that research. This roundup of young researchers is a quick view of people who will be at the heart of U.S. science tomorrow.
Sulfite Reductase Structure at 1.6 Å: Evolution and Catalysis for Reduction of Inorganic Anions
Authors: Crane Brian R. , Siegel Lewis M. , Getzoff Elizabeth D.
Published: October 2006

Fundamental chemical transformations for biogeochemical cycling of sulfur and nitrogen are catalyzed by sulfite and nitrite reductases. The crystallographic structure of
Escherichia coli
sulfite reductase hemoprotein (SiRHP), which catalyzes the concerted six-electron reductions of sulfite to sulfide and nitrite to ammonia, was solved with multiwavelength anomalous diffraction (MAD) of the native siroheme and Fe
4
S
4
cluster cofactors, multiple isomorphous replacement, and selenomethionine sequence markers. Twofold symmetry within the 64-kilodalton polypeptide generates a distinctive three-domain α/ β fold that controls cofactor assembly and reactivity. Homology regions conserved between the symmetry-related halves of SiRHP and among other sulfite and nitrite reductases revealed key residues for stability and function, and identified a sulfite or nitrite reductase repeat (SNiRR) common to a redox-enzyme superfamily. The saddle-shaped siroheme shares a cysteine thiolate ligand with the Fe
4
S
4
cluster and ligates an unexpected phosphate anion. In the substrate complex, sulfite displaces phosphate and binds to siroheme iron through sulfur. An extensive hydrogen-bonding network of positive side chains, water molecules, and siroheme carboxylates activates S-O bonds for reductive cleavage.
Titanic Protein Gives Muscles Structure and Bounce
Authors: Barinaga Marcia
Published: October 2006

One for the record books: Researchers at the European Molecular Biology Laboratory in Heidelberg, Germany, report in
Science
the complete amino acid sequence of the largest protein known—a muscle protein fittingly called titin. But it's more than just a record-breaker. The sequence suggests how titin may aid in muscle assembly and help muscles to spring back into shape after being stretched.
A Heterodimeric Transcriptional Repressor Becomes Crystal Clear
Authors: Andrews Brenda J. , Donoviel Michael S.
Published: October 2006

The crystal structure of a heterodimeric transcriptional repressor from yeast,
a
1/alpha-2, reported in the same issue of
Science
, reveals a mechanism for ensuring DNA-binding specificity that may be used by many other DNA-binding heterodimers. B. J. Andrews and M. S. Donoviel explain how sequence specificity is controlled by the spacing between the proteins, which must match that of the contact points on the DNA. The carboxyl-terminal tail of alpha-2 is the key interface with
a
1 and determines the interprotein distance.
House Bundles 7 R&D Programs
Authors: Lawler Andrew
Published: October 2006

The U.S. House of Representatives has passed an omnibus bill authorizing 1996 spending levels for virtually all the government's nonmedical civilian research programs. The debate on the House floor provided a stark view of the differences between Democrats and Republicans on priorities for R&D.
Hints of a Planet Orbiting Sunlike Star
Authors: Glanz James
Published: October 2006

Two Swiss astronomers believe they have the first evidence for a planet outside our solar system that orbits a sunlike star. They have detected an apparent wobble in a star just outside the Great Square of Pegasus, which may be caused by a planet at least half the size of Jupiter swinging around thestar in a tight orbit. The observation has been confirmed by a second group, but it is controversial because conventional theories suggest that planets that large don't form so close to a star.
Can Deep Bacteria Live on Nothing But Rocks and Water?
Authors: Kaiser Jocelyn
Published: October 2006

Researchers at the Pacific Northwest Laboratory in Richland, Washington, have found bacteria in anaquifer 1500 meters below ground that appear to be living off hydrogen generated by a reaction between basalt and ground water. If so, they would be the first organisms known to obtain their energy froma source completely independent of the sun.
Challenging an Ice-Core Paleothermometer
Authors: MacAyeal Doug
Published: October 2006

Temperatures measured in a borehole in the Greenland ice sheet can offer clues about the past history of the Earth's surface temperature and climate. MacAyeal in his Perspective provides background and commentary to accompany a research report by Cuffey
et al.
which challenges previous climate histories derived from ice-core oxygen isotope data, and offers a new calibration of this “paleothermometer” based on a climate history derived from borehole temperatures.
Large-Scale Interplanetary Magnetic Field Configuration Revealed by Solar Radio Bursts
Authors: Reiner M. J. , Fainberg J. , Stone R. G.
Published: October 2006

An instantaneous view of the interplanetary extension of the solar magnetic field is provided here by measurements from a space platform at high ecliptic latitudes of the trajectories of individual type III solar radio bursts. The Ulysses spacecraft provides this unique vantage point with an orbit taking it far from the ecliptic plane. The Ulysses radio measurements illustrate the capability of detecting and tracking coronal disturbances as they propagate through the interplanetary medium.
Defining the First Steps on the Path Toward Cell Specialization
Authors: Roush Wade
Published: October 2006

Boston, Massachusetts—In this issue of
Science
(
p. 637
and
p. 641
), a team of researchers in Paris and Cambridge, Massachusetts, has provided a clue to a central mystery in developmental biology: How do two cells with identical sets of genes develop along different paths? In one species of bacteria, a protein called SpoIIE initiates a cascade of biochemical changes on only one side of a burgeoning cell membrane, causing one of the new cells to become a specialized bacterial spore. This asymmetrical process may depend on differences in the cell sizes, a phenomenon that also seems to play a role in cell specialization in other species.
Animal Oddballs Brought Into the Ancestral Fold?
Authors: Kerr Richard A.
Published: October 2006

Paleontologists have long debated whether the bizarre Ediacara—blobs of living matter that inhabited Earth before the Cambrian Period's explosion of new species some 540 million years ago—were an evolutionary dead end or ancestors of later species. New dates for Ediacaran fossils, reported in this issue of
Science
(
p. 598
), lend support to the ancestral camp. The Ediacara didn'tdie out in the Precambrian, as many supposed, but persisted at least up to the beginning of the Cambrian.
Cross-Arc Geochemical Variations in the Kurile Arc as a Function of Slab Depth
Authors: Ryan Jeffrey G. , Morris Julie , Tera Fouad , Leeman William P. , Tsvetkov Andrei
Published: October 2006

Lavas from transects across the Kurile Islands arc showed geochemical variations related to changes in the compositions of fluids derived from the subducting slab. Enrichment factors for boron, cesium, arsenic, and antimony, all elements with strong affinities for water, decreased across the arc. This decrease is presumably related to losses of water-rich fluids during the dehydration of the subducting plate. Enrichments of potassium, barium, beryllium-10, and the light rare earth elements remained constant; these species may move in silica-rich fluids liberated from the slab at greater depths.
Central Command Neurons of the Sympathetic Nervous System: Basis of the Fight-or-Flight Response
Authors: Jansen Arthur S. P. , Van Nguyen Xay , Karpitskiy Vladimir , Mettenleiter Thomas C. , Loewy Arthur D.
Published: October 2006

During stress, the activity of the sympathetic nervous system is changed in a global fashion, leading to an increase in cardiovascular function and a release of adrenal catecholamines. This response is thought to be regulated by a common set of brain neurons that provide a dual input to the sympathetic preganglionic neurons regulating cardiac and adrenal medullary functions. By using a double-virus transneuronal labeling technique, the existence of such a set of central autonomic neurons in the hypothalamus and brainstem was demonstrated. These neurons innervate both of the sympathetic outflow systems and likely function in circumstances where parallel sympathetic processing occurs, such as in the fight-or-flight response.
Imaging the Electron Density in the Highest Occupied Molecular Orbital of Glycine
Authors: Zheng Y. , Neville J. J. , Brion C. E.
Published: October 2006

The spherically averaged electron density distribution of the highest occupied molecular orbital (HOMO) for the amino acid glycine has been determined by multichannel electron momentum spectroscopy. Comparison of the measured HOMO electron momentum distribution with near-Hartree-Fock limit and density functional theory (DFT) calculations for the Boltzmann-weighted sum of the eight predicted stable conformers indicates that electron correlation effects must be included in order to adequately reproduce the experimental results for glycine. The best-fitting DFT calculation determined with the Becke-Perdew gradient-corrected exchange-correlation functional was used to generate HOMO electron density maps for oriented glycine conformers. The result is shown for the most stable conformer.
Quake Prediction Tool Gains Ground
Authors: Kerr Richard A.
Published: October 2006

Greek researchers have come close to predicting three large earthquakes this year by monitoring electrical signals in the crust. Although seismologists don't fully understand the method, and some believe its claimed successes have been due to luck, it is attracting a lot of attention in the earth science community.
Sifting Mitosis, Cell Fate in Fly Eyes
Authors: Roush Wade
Published: October 2006

Exactly how cell division and cell fate determination are related during embryonic development has been a mystery. In the fruit fly, for example, one possibility is that the two waves of cell division (mitosis) that sweep through the developing eyes set the genetic switches that enable the cells to respond to developmental signals from their neighbors. But by engineering flies with a human gene that prevents the second mitotic wave, researchers show in this issue of
Science
(
p. 983
) that cell division is not required for the subsequent round of differentiation, although it is necessary for the eye to have adequate numbers of all cell types. A similar pattern may occur elsewhere in development, biologists speculate.
Scientists Attacked for ‘Patenting' Pacific Tribe
Authors: Taubes Gary
Published: October 2006

Via the Internet, a small Canadian group has charged medical researchers in Papua New Guinea and at the National Institutes of Health with patenting individuals from the Hagahai tribe. Although researchers actually patented a virus-infected cell line—and arranged to share royalties with the Hagahai—newspaper headlines have painted the scientists as thieves and scientific “vampires”.
Global Team Keeps Low Profile As It Works on Next Collider
Authors: Lawler Andrew
Published: October 2006

Menlo Park, California—Physicists from Europe, Japan, and the United States are quietly working on technologies that they hope will form the basis for a behemoth atom smasher, the Next Linear Collider. Drawing a lesson from the demise of the Superconducting Super Collider, they are getting an international collaboration together before, rather than after, seeking construction funds.
Government Focuses Funds, and Hopes, on Elite Teams
Authors: Kinoshita June
Published: October 2006

Nanjing—China is pouring money into national “key“ labs in an attempt to focus limited resources on the best scientists. Several of these labs have achieved world-class status. But some scientists are worried that the large number of labs—155 and growing—and reluctance to enforce high standards could spread resources too thinly
Agriculture Finds a Niche; Drug Researchers Seek Help
Authors: Kinoshita June
Published: October 2006

Guangzhou—The quest for food has put agricultural biotechnology scientists in China on a level that in some cases leads the world. At the same time, pharmaceutical research suffers from many weaknesses and lags behind what is being done elsewhere.
Crystal Structure of the Xanthine Oxidase-Related Aldehyde Oxido-Reductase from
D. gigas
Authors: Romão Maria J. , Archer Margarida , Moura Isabel , Moura José J. G. , LeGall Jean , Engh Richard , Schneider Monika , Hof Peter , Huber Robert
Published: October 2006

The crystal structure of the aldehyde oxido-reductase (Mop) from the sulfate reducing anaerobic Gram-negative bacterium
Desulfovibrio gigas
has been determined at 2.25 Å resolution by multiple isomorphous replacement and refined. The protein, a homodimer of 907 amino acid residues subunits, is a member of the xanthine oxidase family. The protein contains a molybdopterin cofactor (Mo-co) and two different [2Fe-2S] centers. It is folded into four domains of which the first two bind the iron sulfur centers and the last two are involved in Mo-co binding. Mo-co is a molybdenum molybdopterin cytosine dinucleotide. Molybdopterin forms a tricyclic system with the pterin bicycle annealed to a pyran ring. The molybdopterin dinucleotide is deeply buried in the protein. The
cis
-dithiolene group of the pyran ring binds the molybdenum, which is coordinated by three more (oxygen) ligands.
Varmus Puts His Stamp on NIH
Authors: Marshall Eliot
Published: October 2006

After 2 years as director of the National Institutes of Health, Harold Varmus has pulled off a quiet revolution. He has improved morale, stemmed the hemorrhage of top talent to universities and industry, made several key scientific appointments, and stepped up reviews of intramural science. He will soon face a tough test as the budget squeeze tightens.
Double Duty at NIH
Authors: Marshall Eliot
Published: October 2006

A powerful incentive in recruiting top scientists to administrative posts at the National Institutes of Health— including NIH Director Harold Varmus—is the opportunity to continue running a lab. But some wonder whether these arrangements entail a conflict of interest.
LEPing Up to Higher Energies
Authors: Taubes Gary
Published: October 2006

This month, physicists at CERN, the European Laboratory for Particle Physics, are collecting data 24 hours a day as the laboratory's newly upgraded Large Electron-Positron Collider (LEP) smashes particles together at nearly twice its previous energy. The high energies and clean collisions have raised hopes that this accelerator run will yield the first glimpses of the long-sought “supersymmetric” particles.
Consortia to Boost Efforts to Develop Genome Industry
Authors: Normile Dennis
Published: October 2006

Tokyo—The Japanese government and several high-tech companies are poised to start a joint venture to tap the commercial value of new knowledge and technologies relating to gene function in an effort to stay abreast of their U.S. and European competitors
A Population Genetic Test of Selection at the Molecular Level
Authors: Taylor M. F. J. , Shen Y. , Kreitman M. E.
Published: October 2006

The role of natural selection in molecular evolution has been inferred primarily by rejection of null hypotheses based on neutral theory, rather than by acceptance of specific predictions based on selection. In this report, a population genetic test of a specific prediction for selection on DNA polymorphism is presented. Pyrethroid insecticide use constitutes an experiment for which form of selection and molecular target (voltage-gated sodium channels) are both known. As predicted, differential pyrethroid selection on tobacco budworm populations generated significant geographic heterogeneity in sodium channel marker allele frequencies, compared with arbitrary loci.
The Centromere: Hub of Chromosomal Activities
Authors: Pluta A. F. , Mackay A. M. , Ainsztein A. M. , Goldberg I. G. , Earnshaw W. C.
Published: October 2006

Centromeres are the structures that direct eukaryotic chromosome segregation in mitosis and meiosis. There are two major classes of centromeres. Point centromeres, found in the budding yeasts, are compact loci whose constituent proteins are now beginning to yield to biochemical analysis. Regional centromeres, best described in the fission yeast
Schizosaccharomyces pombe
, encompass many kilobases of DNA and are packaged into heterochromatin. Their associated proteins are as yet poorly understood. In addition to providing the site for microtubule attachment, centromeres also have an important role in checkpoint regulation during mitosis.
Image Enhancement with Polymer Grid Triode Arrays
Authors: Heeger Alan J. , Heeger David J. , Langan John , Yang Yang
Published: October 2006

An array of polymer grid triodes connected by a common grid functions as a “plastic retina,” providing local contrast gain control for image enhancement. This simple device, made from layers of conducting polymers, functions as an active resistive network that performs center-surround filtering. The polymer grid triode array with common grid is a continuous analog of the discrete approach of Mead, with a variety of fabrication advantages and significant savings in area within the unit cell of each pixel.
Chernobyl's Thyroid Cancer Toll
Authors: Balter Michael
Published: October 2006

Geneva—Radiation scientists now accept that the large increase in childhood thyroid cancers, particularly in Belarus and Ukraine, is the result of radiation released by the Chernobyl nuclear accident. The new focus is on trying to explain why the cancer epidemic is so virulent.
Reactive Immunization
Authors: Wirsching Peter , Ashley Jon A. , Lo Chih-Hung L. , Janda Kim D. , Lerner Richard A.
Published: October 2006

For almost 200 years inert antigens have been used for initiating the process of immunization. A procedure is now described in which the antigen used is so highly reactive that a chemical reaction occurs in the antibody combining site during immunization. An organophosphorus diester hapten was used to illustrate this concept coined “reactive immunization.” The organophosphonate recruited chemical potential from the immune response that resembled the way these compounds recruit the catalytic power of the serine hydrolases. During this recruitment, a large proportion of the isolated antibodies catalyzed the formation and cleavage of phosphonylated intermediates and subsequent ester hydrolysis. Reactive immunization can augment traditional immunization and enhance the scope of catalytic antibody chemistry. Among the compounds anticipated to be effective are those that contain appropriate reactive functionalities or those that are latently reactive, as in the mechanism-based inhibitors of enzymes.
Control of Cell Fate by a Deubiquitinating Enzyme Encoded by the
fat facets
Gene
Authors: Huang Yongzhao , Baker Rohan T. , Fischer-Vize Janice A.
Published: October 2006

Ubiquitin is a highly conserved polypeptide found in all eukaryotes. The major function of ubiquitin is to target proteins for complete or partial degradation by a multisubunit protein complex called the proteasome. Here, the
Drosophila fat facets
gene, which is required for the appropriate determination of particular cells in the fly eye, was shown to encode a ubiquitin-specific protease (Ubp), an enzyme that cleaves ubiquitin from ubiquitin-protein conjugates. The Fat facets protein (FAF) acts as a regulatory Ubp that prevents degradation of its substrate by the proteasome. Flies bearing
fat facets
gene mutations were used to show that a Ubp is cell type- and substrate-specific and a regulator of cell fate decisions in a multicellular organism.
Al Coordination Changes in High-Pressure Aluminosilicate Liquids
Authors: Yarger J. L. , Smith K. H. , Nieman R. A. , Diefenbacher J. , Wolf G. H. , Poe B. T. , McMillan P. F.
Published: October 2006

Understanding the effect of pressure on aluminosilicate glass and liquid structure is critical to understanding magma flow at depth. Aluminum coordination has been predicted by mineral phase analysis and molecular dynamic calculations to change with increasing pressure. Nuclear magnetic resonance studies of glasses quenched from high pressure provide clear evidence for an increase in the average coordination of Al with pressure.
A Gap in the Highest Energy Cosmic Ray Spectrum as a Signature of Unification Scale Physics
Authors: Sigl Günter , Lee Sangjin , Schramm David N. , Bhattacharjee Pijushpani
Published: October 2006

Recent experimental data seem to indicate that there is significant structure in the cosmic ray spectrum above 10
18
electron volts (eV). Besides a dip at ∼5 × 10
18
eV, two events above 2 × 10
20
eV have been observed. The implications for the existence of the Greisen-Zatsepin-Kuzmin cutoff, a long-lasting and still open question in cosmic ray physics, are discussed. This cutoff at a few times 10
19
eV, caused by energy losses in the cosmic microwave background, has been predicted to occur in most acceleration models involving extragalactic sources. An acceleration origin of particles above 10
20
eV within a few megaparsecs cannot be ruled out yet. However, persistence of the apparent gap in the existing data at a quadrupled total exposure would rule out many acceleration models at the 99 percent confidence level for any source distance. Particles above 10
20
eV might then be directly produced by decay from some higher energy scale in contrast to acceleration of charged particles.
Japan Pumps Up Budget for Table-Top Short-Pulse Lasers
Authors: Normile Dennis
Published: October 2006

Tokyo—Japan is thinking small in science—on a grand scale. The goal is to squeeze the capabilities of high-power lasers into a new generation of lasers that can fit on a table top. A $100 million a year project is gearing up to build an Advanced Photon Research Center that will extend the abilities of short-pulse lasers and turn them into new tools for accelerating particles, creating x-ray holograms of living cells, and exploring ultrahigh-speed phenomena.
Sperm Protein Makes Its Mark Upon the Worm Embryo
Authors: Roush Wade
Published: October 2006

Females seem stuck with the work of childrearing, even in the earliest stages of embryogenesis. No biochemical factors guiding this early development have been traced to the father—until now. Scientists report that SPE-11, a novel protein produced by the sperm of the worm
C. elegans
, may play a vital role in the first few minutes after an egg is fertilized. It may promote crucial intermingling of genetic material from both sperm and egg.
Ecdysis Control Sheds Another Layer
Authors: Truman James W.
Published: October 2006

The process by which a butterfly emerges from a chrysalis, called ecdysis, has been thought to be controlled by eclosion hormone. J. Truman discusses the discovery of a new insect hormone, reported in this issue of
Science
by hacek Zithacek nan
et al.
(
p. 88
), that can also trigger ecdysis—MasETH. The two hormones seem to act sequentially.
Criticality and Parallelism in Combinatorial Optimization
Authors: Macready William G. , Siapas Athanassios G. , Kauffman Stuart A.
Published: October 2006

Local search methods constitute one of the most successful approaches to solving large-scale combinatorial optimization problems. As these methods are increasingly parallelized, optimization performance initially improves but then abruptly degrades to no better than that of random search beyond a certain point. The existence of this transition is demonstrated for a family of generalized spin-glass models and the traveling salesman problem. Finite-size scaling is used to characterize size-dependent effects near the transition, and analytical insight is obtained through a mean-field approximation.
Identification of Ecdysis-Triggering Hormone from an Epitracheal Endocrine System
Authors: Žitňan Dušan , Kingan Timothy G. , Hermesman John L. , Adams Michael E.
Published: October 2006

Developing insects repeatedly shed their cuticle by means of a stereotyped behavior called ecdysis, thought to be initiated by the brain peptide eclosion hormone. Here an ecdysis-triggering hormone, Mas-ETH, is described from the tobacco hornworm
Manduca sexta
. Mas-ETH contains 26 amino acids and is produced by a segmentally distributed endocrine system of epitracheal glands (EGs). The EGs undergo a marked reduction in volume, appearance, and immunohistochemical staining during ecdysis, at which time Mas-ETH is found in the hemolymph. Injection of EGs extract or synthetic Mas-ETH into pharate larvae, pupae, or adults initiates preecdysis within 2 to 10 minutes, followed by ecdysis. Sensitivity to injected Mas-ETH appears much earlier before ecdysis and occurs with shorter latency than that reported for eclosion hormone. The isolated central nervous system responds to Mas-ETH, but not to eclosion hormone, with patterned motor bursting corresponding to in vivo preecdysis and ecdysis. Mas-ETH may be an immediate blood-borne trigger for ecdysis through a direct action on the nervous system.
Fund Fuels a Resurgence of Basic Research
Authors: Pennisi Elizabeth
Published: October 2006

Wellington, New Zealand—Four years ago, New Zealand reorganized its research establishment to give priority to studies likely to have industrial or social payoff. Basic research was given a relatively low priority, and academic research centers were squeezed. Recently, however, the government has swung the pendulum back a little by creating a new funding body for basic research, with a $4 million budget that is scheduled to grow to $15 million by 1997.
Particle Physicists Take to Orbit
Authors: Taubes Gary
Published: October 2006

As prospects for large new accelerators dim, particle physicists are turning to projects in space. By doing do, the physicists gain a vast new source of exotic particles and photons; space science, in turn, gains from the physicists' detector expertise and their habit of working in large collaborations, which may reduce instrument-building costs. Already, one group is proposing to build a large orbiting gamma ray telescope; another has secured funding for an antimatter detector that will fly aboard the International Space Station.
Lord of the Rings: GroES Structure
Authors: Mayhew Mark , Hartl F. Ulrich
Published: October 2006

The crystal structure of the chaparonin GroES, which together with GroEL assists in the folding of many proteins in
Escherichia coli
, is reported in this issue of
Science
by Mande
et al
. (
p. 203
). In this Perspective, M. Mayhew and F. U. Hartl discuss the implications of the new structure for the function of the GroEL:GroES complex.
The Shape of Mars and the Topographic Signature of the Hemispheric Dichotomy
Authors: Smith David E. , Zuber Maria T.
Published: October 2006

Reanalysis of occultation data from the Mariner 9 and Viking Orbiter spacecraft to determine the shape of Mars indicated that the hemispheric dichotomy is not a fundamental feature of the shape of the planet. It is a consequence of an approximately 3-kilometer offset between Mars's center of mass and center of figure, and the boundary, along most of its length, consists of broad, gradual surface slopes over distances of thousands of kilometers. This result was supported by analysis of high spatial resolution Earth-based radar topographic profiles. Any successful model for the origin of the dichotomy must explain a planet with an ellipsoidal shape and a long wavelength gradual topographic transition between the northern and southern hemispheres.
Blue Laser Race Turns Red-Hot
Authors: Service Robert F.
Published: October 2006

In the race to make the first blue-light semiconductor lasers, the lead horse—zinc selenide—has come up slightly lame. Now gallium nitride, a highly touted challenger, has stepped onto the track, as researchers report making the first electrically powered laser from this material. Chip-based blue lasers are expected to be an instant commercial hit, because the short blue wavelengths can be used to pack a lot of data in a very small space.
Pairing Symmetry in Single-Layer Tetragonal Tl
2
Ba
2
CuO
β+δ
Superconductors
Authors: Tsuei C. C. , Kirtley J. R. , Rupp M. , Sun J. Z. , Gupta A. , Ketchen M. B. , Wang C. A. , Ren Z. F. , Wang J. H. , Bhushan M.
Published: October 2006

A high-resolution scanning superconducting quantum interference device microscopy study of tetragonal single-layer Tl
2
Ba
2
CuO
6+δ
films, deposited on tricrystal SrTiO
3
substrates, demonstrates the effect of spontaneously generated half flux quanta. This observation shows that in addition to YBa
2
Cu
3
O
7
, the order parameter symmetry in Tl
2
Ba
2
CuO
6+δ
is consistent with that of a
d

x
2
-
y
2

pair state. This result also rules out any bilayer or twinning effects and any pairing that is incompatible with the fourfold rotational symmetry as in the Tl
2
Ba
2
CuO
6+δ
superconducting system.
DPC4
, A Candidate Tumor Suppressor Gene at Human Chromosome 18q21.1
Authors: Hahn Stephan A. , Schutte Mieke , Shamsul Hoque A. T. M. , Moskaluk Christopher A. , da Costa Luis T. , Rozenblum Ester , Weinstein Craig L. , Fischer Aryeh , Yeo Charles J. , Hruban Ralph H. , Kern Scott E.
Published: October 2006

About 90 percent of human pancreatic carcinomas show allelic loss at chromosome 18q. To identify candidate tumor suppressor genes on 18q, a panel of pancreatic carcinomas were analyzed for convergent sites of homozygous deletion. Twenty-five of 84 tumors had homozygous deletions at 18q21.1, a site that excludes
DCC
(a candidate suppressor gene for colorectal cancer) and includes
DPC4
, a gene similar in sequence to a
Drosophila melanogaster
gene (
Mad
) implicated in a transforming growth factor-β (TGF-β)-like signaling pathway. Potentially inactivating mutations in
DPC4
were identified in six of 27 pancreatic carcinomas that did not have homozygous deletions at 18q21.1. These results identify
DPC4
as a candidate tumor suppressor gene whose inactivation may play a role in pancreatic and possibly other human cancers.
Zinc-Induced Collapse of Augmented Inhibition by GABA in a Temporal Lobe Epilepsy Model
Authors: Buhl Eberhard H. , Otis Thomas S. , Mody Istvan
Published: October 2006

In the kindling model of temporal lobe epilepsy, several physiological indicators of inhibition by γ-aminobutyric acid (GABA) in the hippocampal dentate gyrus are consistent with an augmented, rather than a diminished, inhibition. In brain slices obtained from epileptic (kindled) rats, the excitatory drive onto inhibitory interneurons was increased and was paralleled by a reduction in the presynaptic autoinhibition of GABA release. This augmented inhibition was sensitive to zinc most likely after a molecular reorganization of GABA
A
receptor subunits. Consequently, during seizures, inhibition by GABA may be diminished by the zinc released from aberrantly sprouted mossy fiber terminals of granule cells, which are found in many experimental models of epilepsy and in human temporal lobe epilepsy.