VALLEY RESEARCH

Research News is a digest of science and technology news items arising from research and development magazines, newspapers, trade magazines, newsletters, and other news sources that Valley Research processes daily for the benefit of its customers everywhere. It is provided freely to our customers who are free in turn to post or transmit it to other interested researchers provided only that credit to Valley Research is given. Research News is updated approximately once a week.

Rodolfo Carrera, Editor

WEEK OF JANUARY 23, 2012 [No. 933]

Reversing synaptic deficits in age-related brain cognitive decline:   scientists at UCLA have analyzed brain slices from young, middle-aged and aged rats. Aged rats brains showed a decrease in the addition of acetyl groups to histones proteins in the regulatory regions of the neurotrophic factor (Bndf) gene (that encodes a protein that helps neurons in cognitive centers of the brain to form synapse connections) reducing the gene's expression and impairing of downstream signaling in the aged hippocampus. Treating the brain slices with chemicals that mimic the BDNF protein (inhibits histone deacetylation) increased the density and strength of neuronal connections.

For more information: Nature, January 12 (2011) page 117; J. Neurosci., December 7 (2011) page 17800.

One or more bound planets per Milky Way star from present observations:   an international team lead by scientists from the Universite Pierre and Marie Curie, have realized a statistical analysis of microlensing data (gathered in 2002-2007) that reveals the fraction of stars with bound planets (0.5 - 10 AU distance). They find 17% of stars host Jupiter-mass planets; 52% of stars host Neptune-mass planets; 62% of stars host large Earth-mass planets (5 to 10 times Earth's mass). Therefore these planets are at least as numerous as the stars in the Milky Way and the researchers conclude that starts are orbited by planets as a rule, rather than the exception.

For more information: Nature, January 12 (2011) page 167.

WEEK OF JANUARY 16, 2012 [No. 932]

Accretion-induced brightening of the Galactic black hole coming up next year:   an international team lead by scientists at the Max Planck Institute in Garching have discovered a small, coherent blob of dense ionized gas and dust accelerating along a trajectory that they project will carry it close to and into the accretion zone of the Milky Way's 4-million-sun-masses black hole. By next year the blob will be disrupted by a combination of Rayleigh-Taylor and Kelvin-Helmholtz dynamical instabilities and the tidal shearing arising from the black hole's gravitational force. Through a progressive elongation of the blob, the gas will be dispersed over a broad range of orbital trajectories and some of it could accrete onto the black hole possibly leading to a marked, long-duration brightening of the XR emission of the Sgr A* (the blacks hole's immediately surrounding source of electromagnetic radiation). The brightening of the otherwise dim Galactic black hole (modest XR and IR flares due to a low accretion rate) will be a valuable probe of its little-known surrounding environment. The scale of the incoming cloud is cosmologically modest, about the size of the Solar System, with a mass only about three times that of Earth's. The innermost radius of approach is expected to be ~3,100 x the event horizon.

For more information: Nature, January 5 (2011) pages 51 and 32.

WEEK OF JANUARY 9, 2012 [No. 931]

Ohm's law holds for atomic-scale circuits in nanoelectronics:   an international teams lead by researchers from the University of New South Wales have used an AFM technique to embed atomic-scale wires within crystals of Si and has proven that Ohm's law can hold true for wires just 4 atoms thick an one atom tall. The result comes as a surprise because it had traditionally been expected that quantum effects would cause large deviations from Ohm's law for such nanowires. The group used P atoms to embed atomically thin conduction regions within a crystal of bulk Si. In the atomic precision p-doping process a P atom (with one more electron in its outer shell than Si) replaces a Si atom and donates a free electron to the crystal, thereby raising the conductivity of the doped region. They use the tip of a scanning probe microscope to create a channel in the Si by removing rows of Si atoms. The surface is then exposed to P gas, followed by the deposition of Si atoms on top. The resul is a chain of P atoms embedded inside a Si crystal, an tomic wire. The group found that the resistance of such a wire is constant down to the atomic scale. This means that resistance is proportional to its length and inversely proportional to its area (Ohm's law). That densely doped P atomic wires conduct as well as a regular metal wire, should help in maintaining Moore's law in microelectronics as it comes down in the nm scale.

For more information: Science, January 6 (2011) pages 64 and 45; Physicsworld, January 5 (2011).

WEEK OF JANUARY 2, 2012 [No. 930]

Obervations in Antarctica help to clarify the 2011 conundrum in the Apennine Mountains:   scientists in Washington University in St. Louis have shown that neutrinos with extremely high energies should show up only if superluminal neutrinos are an impossibility. Because Ice Cube is observing such neutrinos, there must be something wrong with an observation of superluminal neutrinos by researchers working on the OPERA experiment run between CERN in Geneva and LNGS in Gran Sasso. OPERA has observed muon neutrinos produced in the collision of protons with a stationary target, reaching detectors after traveling 450 miles some 60 nanoseconds sooner than they would have arrived if they were traveling at the speed of light in vacuum. The proton collisions produce a pulse of pions that were magnetically focused into a long tunnel where they decayed in flight into muons and neutrinos of 17 GeV. The muons were stopped at the end of the tunnel, but the neutrinos traveled to the detector in the Gran Sasso. Decay kinematics dictates that as the neutrino that comes out of pion decay tries to move faster than c, the pion lifetime gets longer and the fraction of pion energy carried by the neutrino gets smaller. The creation of neutrinos at CERN is duplicated naturally when cosmic rays hit Earth's atmosphere. In fact Ice Cube (the 1 km3 observatory of the University of Wisconsin in Antarctica) has observed neutrinos with energies of 100 TeV, which should have come from correspondingly very high energy pions with then unrealistic lifetimes for decay in superluminal neutrinos. The observation of high-energy neutrinos by Ice Cube indicates that these high-energy pions decay according to the standard ideas of physics, generating neutrinos whose speed approaches but is lower than c.

For more information: ScienceDaily, December 23 (2011); Phys. Rev. Lett., December 16 (2011)

WEEK OF DECEMBER 26, 2011 [No. 929]

Molecular energy distribution after light absorption explained:   scientists at Michigan State University have experimentally shown that conservation of angular momentum underlies chemical reactions and determines how molecules move energy around after light absorption. The experiment involved the preparation of two closely related molecules that were specifically designed to undergo the FRET (fluorescence resonance energy transfer) chemical reaction where upon absorption of light, the system is predisposed to transfer that energy from one part of the molecule to another. The result can be used to control and predict chemical reaction pathways.

For more information: ScienceDaily, December 22 (2011).

Earth's rotation measured in the lab:   researchers at the Technical University of Munich have built a stable HeNe ring laser to corroborate the Earth's axis wobble measurements based on the data captured by radio telescopes. They used two counter-rotating laser beams that travel around a square path with mirrors in the corners. When the assembly rotates the co-rotating light has farther to travel than the counter-rotating light. The beams adjust their wavelengths, causing the optical frequency to change. The difference is used to calculate the rotational velocity. The assembly is anchored on a concrete pillar, on a ceramic glass plate, within a pressurized cabin.

For more information: ScienceDaily, December 22 (2011); Phys. Rev. Lett., October 20 (2011) 173904.

WEEK OF DECEMBER 19, 2011 [No. 928]

Two black holes of 10 B solar masses uncovered in the nearby Universe:   team lead by scientists from UC-Berkeley have used a combination of ground-based telescopes and spacecraft observations to uncover the two most massive black holes ever found, both at the centers of giant elliptical galaxies central to massive galaxy clusters. NGC 3842, the brightest galaxy in a cluster at a distance from Earth of 98 Mparsec, has a central black hole with a mass of 9.7 B solar masses. A black hole of comparable mass is present in NGC 4889, the brightest galaxy in the Coma cluster at a distance of 103 Mparsec. These objects probably represent the missing dormant relics of the giant black holes that powered the brightest quasars in the early Universe. The group concludes that these black holes were formed from the dry merging of two gas-poor lenticular galaxies (rather than by gas accretion as in the formation of the smaller black holes) with the black holes stopping gas accretion with their energy production. They merge and form stellar shells, while their black holes spiral towards the center until they coalesce. The result is a spheroidal galaxy that has a larger size and bigger black hole than the progenitors, but nearly unchanged velocity dispersion in the random motion of starts in the central parts of the galaxies.

For more information: Nature, December 8 (2011) page 215 and 187.

WEEK OF DECEMBER 12, 2011 [No. 927]

Carbon dioxide dropped during the onset of the Antarctic glaciation:   an international team lead by scientists at Yale University has studied molecules from ancient algae found in deep-sea sediment and crusts core samples to conclude that a 40% decrease in CO₂ occurred prior to and during the rapid formation of a mile-thick ice sheet over the Antarctic some 34 Myrs ago. For 100Myrs prior to the cooling, earth was warm and wet. Mammals inhabited the Poles with subtropical climates. Then in some 100kyrs, temperatures fell dramatically, many species became extinct, ice covered Antarctic and sea levels fell. The cooling that initiated ice sheet formation was triggered below 600 ppm of CO₂.The present 390 ppm is expected to duplicate this century.

For more information: Science, December 2 (2011) page 1261; ScienceDaily, December 1 (2011).

Ionosphere shown to leak Schumann resonant waves:   scientists at NASA Goddard Center in Greenbelt have used the Vector Electric Field Instrument aboard the C/NOFS satellite to detect Schumann resonance from space at 250 - 500 miles. Until know these resonances were thought to be caged between the ground and the lower boundary of the ionosphere at a height of 60 miles. The 8 Hz waves are created out of lightning bursts (that occur at 50 times /sec on Earth's atmosphere) that create electromagnetic waves that resonantly beat up within the atmospheric layer. The resonances have been detected since the early 1960's always from the ground.

For more information: ScienceDaily, November 29 (2011); Geophys. Res. Lett., November 16 (2011).

WEEK OF DECEMBER 5, 2011 [No. 926]

Starting Alzheimer's dysfunction can be controlled in the lab:   a team lead by scientists at Case Western Reserve University have shown that one of the earliest known impairments caused by Alzheimer's disease, loss of sense of smell, can be restored by removing a plaque-forming protein in a mouse model of the disease. The study confirms that the amyloid beta protein causes the loss by accumulating early in olfactory areas. Mice were given a synthetic liver x-receptor agonist, a drug that clears amyloid beta from the brain. After two weeks on the drug, the mice could process smells normally. After withdrawal of the drug for one week, impairments returned.

For more information: ScienceDaily, November 30 (2011); J. Neurosci., November 2 (2011) page 15962.

Nanostructures used for efficient harmonic generation:   scientists at Rice University have used tilted nanocups to convert red light into blue. The nanocup is a 60-nm silica nanosphere with one hemisphere covered by 35 nm of Au. Plasmonic resonances on the cups strongly interact with light at certain frequencies. The intensity of the harmonic increases by tilting the nanocup with respect to the laser light. The researchers believe that the new 3-D nanostructures can be adapted for frequency doubling in parts of the spectrum where it is not currently possible as well as for optical parametric oscillators and electro-optic and acousto-optic modulators.

For more information: Physicsworld, November 25 (2011); Nano Lett., November 1 (2011).

WEEK OF WEEK OF NOVEMBER 28, 2011 [No. 925]

Dark matter must have a mass greater than 40 GeV:   scientists at Brown University in Providence, Rhode Island, have set the strongest limit to date on the mass of the hypothesized dark matter particle. The constraint is based in the value obtained for gamma ray emission from dark matter annihilation (collision with its anti-particle) in seven dwarf galaxies near the Milky Way, which are full of dark matter and H₂ gas. By using data from NASA's Fermi Gamma-Ray Space Telescope they conclude that if a particle's mass is less than 40 GeV then it cannot be the dark matter particle. They used the observed number of photons in the dwarf galaxies to determine the rate of quark production and from that they established constraints on the mass of dark matter particles and the rate at which annihilate. If the dark matter particle would have mass < 40 GeV, the amount of dark matter in the universe today would be so much that the universe would not be expanding at the observed accelerated rate. The observational measurements are important because they cast doubt on recent results from dark matter collaborations that have reported detecting the dark matter particle in underground experiments at lower energy.

For more information: ScienceDaily, November 23 (2011); Phys. Rev. Lett, December 1 (2011).

WEEK OF NOVEMBER 21, 2011 [No. 924]

Light is created from vacuum through time dependent boundary conditions:   scientists at Chalmers University in Goteborg have managed to capture some of the photons that are constantly appearing and disappearing in the vacuum. They have succeeded in getting photons to leave their virtual state and become real photons (measurable electromagnetic radiation). This dynamic Casimir effect was predicted by Moore in 1970 to occur if virtual photons were allowed to bounce off a mirror that is moving at a sped near c. Instead of varying the physical distance to a mirror, they have varied the electrical distance to an electrical short circuit (a SQUID operating at > 10 GHz) that acts as a mirror for microwaves driven through a waveguide (superconducting Meissner effect). The mirror effectively vibrated at ~c/4. Photons appeared in pairs from the vacuum, which were measured as microwave radiation, to have the precise properties predicted by quantum theory. Because the photons have no mass, relatively little energy (in this case transferred by the ultrafast mirror) is needed to excite them out of their virtual state.

For more information: Nature, November 17 (2011) pages 376 and 303; ScienceDaily, November 18 (2011); Physicsworld, November 17 (2011).

WEEK OF NOVEMBER 14, 2011 [No. 923]

Synthetic molecular mechanical system with directionally controlled motion on a surface:   a team lead by scientists from the University of Groningen have synthesized specially designed complex organic molecules that have four electrically-driven wheels (connected to the body by C=C bonds) for quasi-linear forward motion on a metal surface. By sublimating the molecules on a Cu surface and providing them with sufficiently energetic electrons from the tip of a STM, they were able to drive some of the molecules in a specific direction. The single-molecule nanovehicle is about 4 nm long by 2 nm wide and operates at 7 K. The wheels are actually molecular ratchets (rotary motors that turn in a single direction), some or all of which can be actuated to move when sufficient energetic electrons are supplied by an STM tip. When the STM tip fires electrons at the system, it prompts isomerization of the double bonds in its molecular motor wheels. The unidirectional motors combined with their stereochemical arrangement on the molecule make the nanovehicle move along. With 10 stimulations of at least 500 mV from the STM, isomerization of the double bonds in the molecular wheels is induced (bonds break and re-form the other way around), the wheels turn and the system moves 6 nm forward. Therefore molecules with multiple motors can now be synthesized, deposited, and operated to move directionally across a surface.

For more information: Nature, November 10 (2011) pages 208 and 187; Chem. Eng. News, November 14 (2011) page 7; SienceDaily, November 10 (2011); Physicsworld, November 9 (2011).

WEEK OF NOVEMBER 7, 2011 [No. 922]

Plate tectonics underlies field reversal:   French scientists have concluded that during a given geological period the location of the continents is linked with the frequency of Earth's magnetic field reversals. The team suggests that the conditions at the core-mantle boundary may be correlated with the mantle wide convection through enormous convection cells that result in the circulation of near-molten material within the mantle and ultimately provide the driving force for plate tectonics. This symmetry breaking deep within Earth may be reflected in the distribution of continents. They report a correlation between the rate of field reversals and the extent of north-south asymmetry among continents after studying both phenomena over the past 300 Myrs.

For more information: Physicsworld, October 28 (2011); Geophys. Res. Letts, to be published (2011).

Black hole's accretion disc observed:   a team of scientists has used the Hubble Space Telescope to observe a quasar accretion disc brightly glowing as is being absorbed into its galaxy's central black hole. They have used gravitational microlensing by stars in an intervening galaxy to hugely increase the power of the telescope to allow for a direct measurement of the size and diameter of the disc and the temperatures across different parts of the disc. They used the same technique to observe a group of distant quasars that are gravitationally lensed by the chance alignment of other galaxies in the foreground, and to probe the gas and dust content of intermediate galaxies.

For more information: ScienceDaily, November 4 (2011); Astrophys. J., December 1 (2011).

WEEK OF OCTOBER 31, 2011 [No. 921]

Complex organic matter exists throughout the Universe:   scientists at The University of Hong Kong report observations that suggest that complex organic compounds are not the sole domain of life in planets but can be made naturally by stars. They show that an organic substance commonly found throughout the Universe (on previously unidentified cosmic IR emissions) contains a mixture of aromatic and aliphatic components. The compounds are so complex that their chemical structures resemble those of petroleum. Since petroleum compounds are remnants of ancient life, this type of organic matter was thought to arise only from living organisms. The discovery suggests that complex organic compounds can be synthesized in space even when no life forms are present. By analyzing spectra of star dust formed in supernovae taken by space observatories, they show that stars are making these complex organic compounds on extremely short time scales of weeks and ejecting the nanoparticles into the interstellar space. Old stars seem to be molecular factories capable of manufacturing complex organic compounds under UHV conditions. This organic star dust is similar in structure to complex organic compounds found in meteorites which bombarded the early Earth possibly carrying organic star dust.

For more information: ScienceDaily, October 26 (2011); Nature, to be published (2011).

Frequency comb on a chip within reach:   researchers at NIST have developed a compact laser frequency comb using a low-power semiconductor laser about the size of a shoebox and a high-quality optical cavity (a precisely machined disk of solid quartz crystal) shaped like an ellipse 2 mm wide. The cavity is designed to limit light dispersion and confine the light in a small space to enhance intensity and optical interactions. The IR laser light travels in a loop inside the cavity, generating a train of short pulses and a spectrum of additional shades of IR light. A miniature laser might be substituted in the future to squeeze the entire comb system onto a microchip with the fused silica microcavity easily integrated with other optical and photonic components.

For more information: ScienceDaily, October 26 (2011); Phys. Rev. A, to be published (2011).

WEEK OF OCTOBER 24, 2011 [No. 920]

Dark matter does not behave as thought:   researchers at the Harvard-Smithsonian Center for Astrophysics and the University of Cambridge have analyzed two dwarf galaxies with millions of stars and having 1% of normal matter and 99% dark matter. Measurements indicate that they contain a smooth distribution of dark matter rather than having the dark matter densely packed at their centers. This suggests that the standard cosmological model may be wrong as it assumes that dark matter consists of cold exotic particles that clump together gravitationally. Over time these dark matter clumps grow and attract normal matter forming and holding present day galaxies.

For more information: ScienceDaily, October 17 (2011); Astrophys. J., to be published (2011).

Cascade of intracellular signals in synaptic plasticity uncovered:   scientists at the Cold Spring Harbor Laboratory have solved part of a puzzle concerning the relationship between changes in the strength of the synapses and cognitive disorders due to dysfunctions in neural circuits. The tamping-down of the strength of synapses involves a retraction of receptors (through activation of mGluR receptors and rapid dendritic synthesis of proteins) where neurotransmitters dock. The group has identified the OPHN1 protein as the mediator of the process in hippocampus nerve cells by interaction with protein Endophilin A2/3 and produced after activation of mGluRs.

For more information: ScienceDaily, October 19 (2011); Neuron, October 20 (2011) page 300.

WEEK OF OCTOBER 17, 2011 [No. 919]

Brain protein produced to deal with stress identified:   researchers at the University of Leicester have identified a particular protein that the brain produces in response to stress. Under severe stress the processes on the daily reshaping of brain connectivity are retracted. Nerve cells in the hippocampus, responsible for learning and memory, do not effectively communicate with other cells and show signs of psychiatric disease. Brain cells change the form of their dendritic microspines, both the thin and the mushroom spines (battle to maintain balance on what to remember and what to better forget). The protein lipocalin-2 has been identified as produced in response to stress to reduce the number of mushroom spines and hence future anxiety from stressful events. When the scientists added lipocalin-2 to neurons in culture the way it occurs on stress, neurons started losing their memory spines, the mature, mushroom-shaped ones.

For more information: ScienceDaily, October 9 (2011); Proc. Nat. Acad, Sci., October 3 (2011).

Stellar tidal disruption flares, TDF s spotted:   an international team lead by scientists at New York University have found evidence of black holes destroying stars. When a star orbit is disturbed to pass very near a super-massive black hole at the center of its galaxy, but not near enough to be captured whole by it, it will be torn apart by extreme tidal forces (the force due to the gravitational gradient across the star overwhelms the star's confining force). Some matter falls into the black hole. Much continues in chaotic orbits, crashing into itself and producing TDF s with intense radiation lasting days to months. After filtering out supernovae and active galactic nuclei flares from a survey of 2 million galaxies during 10 years, the researchers detected two TDF s spectra at the nucleus of their galaxy with no other flaring activity before or after.

For more information: ScienceDaily, October 12(2011); Astrophys. J., to be published (2011).

WEEK OF OCTOBER 10, 2011 [No. 918]

Stem cell reprogramming technique shown to be safe:   researchers at the Scripps Institute and the University of Virginia have shown that the standard reprogramming method (first described in 2006) to make stem cells out of adult human own cells can generate induced pluripotent stem cells (iPSC) that have very few DNA structural mutations which are often linked to dangerous cell changes. The method requires the insertion into an ordinary non-stem cell of four special genes, whose activities cause the cell to revert to a state like that of embryonic stem cell. The donor cells selected were not decades-old human skin cells but relatively error-free fibroblast cells from fetal mice which were held only briefly in lab dishes before reprogramming them. After high resolution whole-genome paired-end DNA sequencing searching for mutations they found almost none, with very few changes to the chromosomal sequence appearing during reprogramming. Although there was concern that retroelements would be allowed to escape suppression during the transition to a stem cell state, there was a complete absence of new retroelement transpositions. Deleterious genetic mutations seen in previous studies might have been due to incomplete reprogramming that impaired the cell's DNA-maintenance mechanisms.

For more information: SciendeDaily, October 7 (2011); Cell Stem Cell, October 4 (2011) page 366.

WEEK OF OCTOBER 3, 2011 [No. 917]

Stable room temperature single-mode 8.5 µw Terahertz source built:   researchers at Northwestern University have developed a way to generate Terahertz radiation on a chip that is simpler than any previously developed source. They use QCLs with a special diffraction grating in the laser cavity to produce and mix two high power, high quality, single mode MIR laser beams within a semiconductor chip where a giant nonlinearity is produced. New terahertz photons with a very narrow linewidth and very stable (to current and temperature) spectrum are created within the chip with energy equal to the difference of the MIR lasers' energies.

For more information: ScienceDaily, September 30 (2011); App. Phys. Letts., 99, 131106 (2011).

Plasmonic nanotweezer with integrated heat sink built:   researchers at Harvard University have demonstrated the trapping and rotation of nanoparticles using a template-stripped plasmonic nanopillar incorporating a heat sink (Au-Cu-coated Si base with raised Au-pillar). A 100-fold reduction in heating compared with previous designs is achieved. The design solves the overheating problem of tweezers based on surface plasmons (used to overcome the diffraction limit on laser spot size of optical tweezers). They show the stable trapping of 100 nm polystyrene particles at the top of the pillar, which can be rotated around the nanopillar actively, by manual rotation of the incident linear polarization, or passively, using circularly polarized illumination.

For more information: ScienceDaily, September 27 (2011); Nat. Comms., August 3 (2011).

WEEK OF SEPTEMBER 26, 2011 [No. 916]

Technetium-99m can be produced in hospitals:   researchers at the University of British Columbia have numerically analyzed operation of hospital cyclotrons (used to produce PET radionuclides) to demonstrate that the now scarce medical isotope ^99mTc could be made in them with no need to order it on special nuclear reactors. When ¹⁰⁰Mo is bombarded with protons it transmutes into ^99mTc (short half life). Fine tuning of proton beam energy (16 - 19 MeV), target geometry, irradiation and cooling times are critical as Mo targets are very expensive and the product is contaminated with other unwanted radioactive elements. They conclude that only Mo targets enriched with ¹⁰⁰Mo are viable for efficient ^99mTc production.

For more information: Physicsworld, September 21 (2011); Phys. Med. Biol., August 3 (2011).

Sagittarius impact shaped the Milky Way:   a group lead by scientists of the University of California at Irvine have performed simulations of the response of the Milky Way to the infall of the Sagittarius dwarf galaxy, resulting in the formation of spiral arms, influencing the central bar and producing a flared outer disk. Two ring-like wrappings emerge towards the Galactic anti-center creating a structure reminiscent of the low-latitude arcs observed in that area of the Milky Way. The Milky Way morphology is then not purely secular in origin but its structure has been shaped by low-mass minor mergers which are predicted to be common throughout the Cosmos.

For more information: Nature, September 15 (2011) pages 301 and 286.

WEEK OF SEPTEMBER 12, 2011 [No. 914]

Propagation of nano spin waves demonstrated:   Swedish and Italian scientists have observed a propagating spin wave launched from a spin torque oscillator with a nanoscale electrical contact into an extended Permalloy (NiFe) film through the spin transfer torque effect. The spin waves have tunable frequencies and can propagate for several micrometers. This opens up a new field of magnonics using magnetic waves to fabricate components and circuits that substitute traditional microwave components at much smaller dimensions and cost. These new components are powered by direct current which is the converted into spin waves in the microwave region.

For more information: ScienceDaily, September 10 (2011); Nat. Nanotech., August 28 (2011) (published on line).

Single-molecule electric motor developed:   researchers at Tufts University in Boston have used a low-temperature scanning tunneling microscope to build an electrically controlled molecular motor. The microscope sent an electrical current through the molecule, directing the molecule to rotate in one direction or another. The molecule has an S base and when placed on a conductive slab of Cu it became anchored to it. The butyl methyl sulfide molecule had C and H atoms radiating off forming two arms with 4 carbons on one and one carbon on the other. These C chains were free to rotate around the central S-C bond. Operation was performed at 5 K.

For more information: ScienceDaily, September 5 (2011); Nat. Nanotech., September 4 (2011) (published on line).

WEEK OF SEPTEMBER 5, 2011 [No. 913]

Origin of the ferroelectricity in a multiferrroic material uncovered:   British scientists have used the ESRF in Grenoble to determine how multiferroic materials can be simultaneously magnetically and electrically ordered. They show that their polarization proceeds from the relative displacement of charges of different signs (rather than the transfer of charge between atoms). As the displacement involves a high number of electrons, even small distances can lead to significant polarization. The actual distance of the displacement was measured to be 20 fm (atoms in the material are 100,000. times farther away). The measurement technique uses the interference between charge and magnetic scattering of a powerful, polarized X-ray beam.

For more information: Science, September 2 (2011) page 1273; ScienceDaily, September 3 (2011).

Unaccounted bacteria of the dark ocean carbon cycle identified:   a team lead by scientists at the Bigelow lab in Maine have identified prokaryotes that fix inorganic carbon at globally significant rates in the dark ocean where photosynthesis is not possible. Using single-cell sorting and whole genome amplification of prokaryotes from two subtropical gyres, they obtained genomic DNA from 738 cells representing most lineages which have not been cultured in the laboratory to date. Deciphering of their metabolic capabilities shows that they are capable of trapping carbon dioxide in this deep underwater region between 200 and 1000 m below surface.

For more information: Science, September 2 (2011) page 1296; ScienceDaily, September 2 (2011).

WEEK OF AUGUST 29, 2011 [No. 912]

Forecasting of solar eruptions within grasp:   scientists at Stanford University have detected subsurface signatures of emerging sun spot regions before they appeared on the solar disc. Strong acoustic travel-time anomalies of an order of 12 to 16 sec were detected as deep as 65,000 Km. These anomalies were associated with magnetic structures that emerged with an average speed of 0.3 to 0.6 km/sec and caused high peaks in the photospheric magnetic flux rate one to two days after the detection of the anomalies. Thus, correlated imaging of precursor subsurface magnetic activity may allow anticipation of large sunspot regions before they become visible from Earth.

For more information: Science, August 19 (2011) page 993.

Mechanism for Universe dimming evolution uncovered:   scientists at CSIRO in Australia have studied ultra-luminous IR galaxies some 3 to 5 Byrs away to conclude that at that stage of the Universe's life, it contained considerably more H₂ gas than comparable galaxies in today's Universe. They find that the decline in the molecular gas is similar to the pattern of decline in star formation. The drop-off in both gas availability and star formation seems to have started around the time that Dark Energy took control of the Universe. The accelerating expansion made increasingly difficult for galaxies to capture additional H₂ gas to fuel future star formation.

For more information: ScienceDaily, August 22 (2011); Monthly Notices Royal Astr. Soc., to be published (2011).

WEEK OF AUGUST 22, 2011 [No. 911]

Microwave quantum gate realized:   scientists at NIST in Boulder have produced quantum logic gates by using microwave radiation to obtain quantum control on trapped ions instead of laser beams used until now. Scientists at the Universities of Siegen and Ulm have used microwaves to shield a quantum processor from decoherence. Microwaves are applied via waveguides structures embedded in the microchip where the microfabricated ion trap is integrated (so do not require the expense, large space and alignment of laser systems).The microchip contains electrodes that produce electric fields capable of trapping two ions in the near-field zone just above the chip's surface (30 µ) where the necessary electromagnetic field gradients are produced. Multiple pulses of microwave radiation are then applied to the trapped ions through the waveguide, with the oscillation electromagnetic fields (1-2 GHz) effectively entangling the two ions and executing a quantum gate. The ions are set to a state in which they are decoupled from outside noise. The use of microwaves reduces errors introduced by instabilities in laser beam pointing and power as well as laser-induced spontaneous emissions by the ions. Entanglement of 76% has been produced so far. Low power UV lasers are still needed to cool the ions and observe experimental results.

For more information: Nature, August 11 (2011) pages 181, 185, and 155; ScienceDaily, August 11 (2011).

WEEK OF AUGUST 15, 2011 [No. 910]

Deep tissue microscope demonstrated:   scientists at Purdue University have developed vibrational photoacoustic microscopy (VPAM) that targets specific chemical bonds to pinpoint unlabelled molecules in biological tissue at depths of up to several mm's, over 10 times more than current methods. 3D images of plaque lining arteries have been created. A laser pulse is fired and scanned through the sample to excite a specific vibrational mode associated with the C-H bonds that abound in body fat. Wavelength is chosen to minimize absorption. Fat molecules heat and expand generating pressure waves at ultrasound frequencies whose arrival time and intensity are measured by a scanning transducer to create a 3D image giving the fat location.

For more information: Physicsworld, August 2 (2011); Physical Rev. Lett., to be published (2011).

Heterogeneous catalysts with isolated single-atom active sites fabricated:   a team headed by researchers in the Dalian Institute has used a wet-chemistry method to prepare catalysts featuring single isolated precious-metals atoms supported on a metal oxide surface. By tuning the temperature, pH, and other parameters in a co-precipitation process they have sidestepped problems of making uniform sub-nm particles and their tendency to diffuse and agglomerate deactivating catalysts. The procedure yields nanocrystallites of Fe₂O₃ with isolated Pt atoms dispersed across the surface. The single-atom catalyst maximizes metal use, remains stable under typical reaction conditions and is at least 2-3 times more active than the other catalysts.

For more information: Chem. Eng. News, August 1 (2011) page 10; Nat. Chem., on line.

WEEK OF AUGUST 8, 2011 [No. 909]

Conversion of human skin cells into brain cells demonstrated:   scientists from the Gladstone Institute in San Francisco have developed efficient and robust methods for transforming adult human skin cells into functioning neurons that are capable of transmitting brain signals. The production of reprogrammed skin cells, that are not yet ready for human transplantation, is achieved without use of embryonic stem cells by using only a microRNA and two genes.

For more information: SciendeDaily, August 2 (2011); Cell Stem Cell, July 28 (2011).

Path manipulation in non-linear light conversion shown:   researchers at Duke University have created a metamaterial that allows non-linear second-harmonic generation while steering the light produced at will. The device, with dimensions 6"x 8"x 1", is made of individual pieces of the same fiberglass material used in circuit boards arranged in parallel rows. Each piece is etched with Cu circles, each with a tiny gap spanned by a diode which creates non-linearity with light.

For more information: Physicsworld, August 1 (2011); Physical Rev. Lett., to be published (2011).

Earth Trojan asteroid observed and confirmed:   an international team of scientists have realized an archival search of IR data for possible Earth Trojan asteroids, producing the candidate 2010 TK7. They subsequently made optical observations which established that the candidate is a Trojan companion of Earth, librating around the leading Lagrange triangular point L4 (60 degrees ahead in the orbit of Earth). Its diameter is 300 m and its orbit is stable over 10,000 years.

For more information: Nature, July 28 (2011).

WEEK OF AUGUST `, 2011 [No. 908]

Powerful Alfven waves that sway energetic spicules heat the corona:   an international team lead by scientists from NCAR in Boulder have used the NASA's SDO observations to show that the region above the Sun's chromosphere has a high density of Alfven waves (magnetic plasma waves at EUV and XR wavelengths) with energies over a hundred times higher than previously thought. With amplitudes ~20 km/s and speeds of 200 km/s they can heat the Sun's corona to millions of degrees and drive the solar wind into 100's km/s. These oscillations play a critical role in transporting heat from the Sun's interior by riding on the energetic type II spicules (short-lived jets of hot gas that shoot in the corona at more than 100,000 km/h down from the chromosphere at 6,000 degrees) and carrying energy into the corona. The AIA instruments used, boast high spatial and temporal resolution, enough to detect structures and motions across regions of the Sun as small as 500 km and generate images every 12 seconds at different wavelengths. Now that the real power of the waves has been revealed, the next step in understanding the very high temperature of the quiet corona and the fast solar wind is to study the damping of the waves into the plasma so the wave's energy is transferred to gas in the corona.

For more information: Nature, July 28 (2011) page 477; Physicsworld, July 28 (2011); Science Daily, August 1 and July 28 (2011).

WEEK OF JULY 25, 2011 [No. 907]

Evidence of dark energy uncovered in the cosmic microwave background:   a team headed by scientists at UC-Berkeley has uncovered ppm fluctuations in the temperature (2.7K) of the CMB that deviate from a Gaussian distribution. These fluctuations are caused by interactions with large-scale structures in the universe. The gravitational influence of an average 50 of these structures (which are dominated by massive clumps of dark matter and include galaxy clusters) will each deflect the path of the photons reaching the used telescope through dark matter reduced lensing .

For more information: Physicsworld, July 15 (2011); Physical Rev. Lett., to be published (2011).

Low-energy termination of fibrillation in-vivo demonstrated:   an international team headed by scientists of Cornell University and Max Planck institute has established the relationship between the response of the cardiac tissue to an electric field and the spatial distribution of heterogeneities in the scale-free coronary vascular structure. They show that in response to a pulsed electric field, these heterogeneities serve as nucleation sites for the generation of intramural electric waves. Simultaneous and direct access to multiple vortex cores results in rapid synchronization of cardiac tissue and then, efficient termination of fibrillation.

For more information: Nature, July 14 (2011) pages 235 and 181.

Earth's primordial heat supply has not yet been exhausted:   an international team of scientists have used the KamLAND detector in Japan to measure the flux of anti-electron neutrinos emanating from deep within the Earth. They have shown that about 50% of the heat flow given off by the Earth to space is generated by the radioactive decay of elements such as ²³⁸U and ²³²Th (located in the lithosphere and mantle and out of the iron core) and their decay products.

For more information: Physicsworld, July 19 (2011); Nat. Geoscience, July 17 (2011).

WEEK OF JULY 18, 2011 [No. 906]

Table-top antimatter production shown:   scientists from UC-Riverside have discovered a new way to create positronium. They irradiated samples of silicon with laser light and then implanted positrons on the surface. They found that the laser light frees up Si electrons that then bind with the positrons to make positronium. With this method, a substantial amount of positronium can be produced in a wide temperature range and in a very controllable way. The irradiation of the surface with a laser just before the positrons arrive produces electrons that help the positrons to leave the surface (by forming positronium that leaves the surface) and then avoid annihilations.

For more information: ScienceDaily, July 11 (2011); Physical Rev. Lett., to be published (2011).

Black holes are not activated by galaxy collisions after all:   researchers at European observatories have uncovered that most of the huge black holes in the centers of galaxies in the past 11 Byrs were not turned on by mergers between galaxies (with the disrupted material becoming fuel for the central black hole), as previously thought. They learned that active nuclei are mostly found in large massive galaxies with lots of dark matter and that most active nuclei reside in galaxies with masses about 20 times larger than the value predicted by merger theory. The black holes are fed by processes within the galaxy itself rather than galaxy collisions.

For more information: ScienceDaily, July 14 (2011); As. Phys. J., to be published (2011).

WEEK OF JULY 11, 2011 [No. 905]

Eyesight triggered by electrical processes:   scientists from Syracuse University have shown that isomerization (structural change of chromophones in the retina) is not the first process in the eye vision process as has been believed in the last fifty years. They synthesized chromophones that were missing a key chemical group. These chromophones were then incorporated into living single-cell algae (Chlamydomonas reinhardtii). After a series of tests the algae continued to respond to light stimuli in the same way. Then they concluded that redistribution of electrons with chromophones is enough to polarize chromophones with no need for shape change.

For more information: Physicsworld, July 8 (2011); Chem. and Biol., to be published (2011).

A graphene based molecular spintronics device built:   a team of European researchers have used a graphene nanoconstriction with grafted magnetic molecules (TbPc₂, with Pc= phthalocyananine) to electrically detect the magnetization reversal of the molecules in proximity with graphene and show their information storage capability. A magnetoconductivity signal as high as 20% is found for the spin reversal, revealing the uniaxial magnetic anisotropy of the TbPc₂ quantum magnets. The new ultra-sensitive device (size 10 nm) enables the magnetic reading at the molecular scale (the previous record of sensitivity has been beaten by ~ 100).

For more information: ScienceDaily, June 29 (2011); NanoLetters, June 7 (2011).

WEEK OF JULY 4, 2011 [No. 904]

There might not be quantum graininess of space after all:   scientists from the CEA Saclay have used data from the ESA's Integral gamma-ray observatory to search for the difference in polarization between high- and low-energy gamma rays emitted during one of the most powerful GRB's ever seen. GRB 041219A took place in December 19 of 2004 and was in the top 1% of GRBs for brightness. The scientists searched for differences in the polarization at different energies that would have been created by the quantum graininess of the space traveled, but found none to the high accuracy limits of the data. Integral's observations are about 10,000 times more accurate than any previous and show that quantum graininess must be at 10^-48 m or smaller.

For more information: Physical Rev. D, June 28 (2011).

A two-component nanoparticle system treats tumors efficiently:   researchers at MIT have developed a drug-delivery system with: polyethylene glycol-coated Au nanorods and cancer-drug-bearing liposomes tagged with a peptide that binds to an enzyme in the blood-clottting cascade. They inject mice with the nanorods, and then shine NIR light on the rodent's tumors, locally heating the nanorods that find their way to the tumor. The heat damages the tumor's blood vessels and initiates clotting. Then, they inject the mice with tagged liposomes loaded with the cancer drug doxorubicin, delivering 40 times as much drug dose as with one particle alone.

For more information: Chem. Eng. News, June 27 (2011) page 12; Nature Materials, June 19 (2011).

WEEK OF JUNE 27, 2011 [No. 903]

Voyager finds a bubbling heliosheath and a diffuse heliopause:   scientists from the Johns Hopkins University have used the Voyager's Low-Energy Charged Particle Instrument to determine the solar wind's velocity which, after four years of crossing the termination shock, has been decreasing its radial velocity to zero while moving through the heliosheath. Data from the spacecraft have shown a gentle decrease in the flow velocity of the solar wind at the heliopause, not the abrupt discontinuity predicted by the theories. The magnetic field in the heliosheath is shown as a tumultuous foam of magnetic bubbles, different from the expected magnetic field line arcs. They believe that Voyager 1 has not yet crossed the heliopause into interstellar space, when there should be a sudden drop in the density of hot particles of the heliosheath and an increase in the density of cold particles of the interstellar plasma. They estimate that the heliopause is at 18 Bkm, so the spacecraft could exit the transition layer and enter the galactic medium by the end of 2012. Another team from NASA has found bubbles of magnetism, each about 160 Mkm wide, in the heliosheath. The bubbles appear to be self-contained and disconnected from the broader solar magnetic field. These bubbles appear to be our first line of defense against galactic cosmic rays.

For more information: Nature, June 16 (2011) page 359; Physicsworld, June 22 (2011).

WEEK OF JUNE 20, 2011 [No. 902]

Cellular laser built:   scientists from the Massachusetts General Hospital and the Harvard Medical School have shown how to induce lasing in a single living biological cell. By shinning intense blue light onto fluorescent protein molecules in a cell, they made the molecules generate intense, monochromatic, directional green light. They put human embryonic kidney cells into a Petri dish and then added the DNA that encodes for green fluorescence protein (GFP) from jellyfish Aequorea Victoria to the cells. They then attached a drop of solution containing these re-programmed cells onto a Fabry-Perot etalon formed by two mirrors of 3 cm diameter at 200µ distance. They then focused nanosecond blue laser pulses onto the space between the mirrors and moved the mirrors around until they were able to shift a single cell into the beam focus. With pulses with energy above a threshold of 1 nJ, the energy of the emitted green light increased sharply and its spectrum narrowed to just a few well-defined wavelengths. Lasing occurred when enough protein molecules were in an excited state to generate stimulated rather than spontaneous emission with the emitted light amplified as it bounces between the mirrors. The material used was made entirely from living tissue and remained alive after emitting hundreds of laser pulses.

For more information: Physicsworld, June 12 (2011); Nature Photonics, June 12 (2011).

WEEK OF JUNE 13, 2011 [No. 901]

New type of brighter supernova uncovered within dwarf galaxies:   an international group lead by scientists at Caltech has discovered a new class of astronomical explosions that can not be explained by models used in previous sightings. They have been identified in dim, small galaxies of a few billion stars. The supernovae are a hundred times brighter than their host galaxies. The new stellar explosions are: an order of magnitude brighter than others, hot (10,000 to 20,000 K), expanding rapidly (10,000 km/s), lacking hydrogen, and fading away slowly (50 days to fade away). The spectral data cannot be explained by typical gamma ray emission due to radioactive decay of heavy nuclei synthesized in the highly energetic event. It cannot be explained either by radiation emission or recombination of surrounding hydrogen. The new six supernovae detected in the last six years have spectra that are very blue, with the brightest wavelengths shining in the UV. They might be either a pulsating star of some hundred sun masses or a magnetar neutron star. The explosions determine the position of the previously undetected dwarf galaxies which allow their study two months later. The observations provide with the spectrum of the interstellar gas that fills the dwarf galaxies where the supernovae are and so they reveal their compositions.

For more information: ScienceDaily, June 8 (20110; Physicsworld, June 8 (2011); Nature, June 8 (2011).

WEEK OF JUNE 6, 2011 [No. 900]

New limit on the electric dipole moment of the electron experimentally set:   scientists at Imperial College London have looked for evidence of an aspheric distortion to the shape of the electron and its interactions with electric fields. Their experimental results using cold polar molecules limit the magnitude of the electron's electric dipole moment to less than 10.5 x 10^-28 ecm (16 orders of magnitude weaker than the known magnetic dipole moment of the electron).

For more information: Nature, May 26 (2011) pages 493 and 459.

NMR spectroscopy shown with no use of magnet:   researchers at the PNWL in Richland have done NMR spectroscopy of hydrocarbons by relying on the nuclear spin interaction of molecular nuclei rather than on their much larger interaction with the external magnetic field (where the NMR signal increases with the square of the applied field). The spin-spin coupling effect is much smaller but it is still seen in a standard NMR spectrum as splitting of the main absorption peaks.

For more information: Physicsworold, May 29 (2011); Nature Phys., to be published.

Mars may have formed in just 3 Myr of the solar System formation:   researchers at the University of Chicago have determined Mars abundance ratio of Hf/W and re-evaluated Mars age using a chronometer based on the decay of Hf¹⁸² to W ¹⁸². By combining their calculated bulk silicate Mars Hf/W ratio with the W isotopic compositions of Martian meteorites, they were able to determine an age of core formation for Mars of around 2 to 4 Myrs after the Solar System began to form. Such rapid growth explains why Mars is much smaller than Earth and Venus.

For more information: Nature, May 26 (2011) pages 489 and 460.

WEEK OF MAY 30, 2011 [No. 899]

Star rotation periods measured on a star cluster:   researchers in Harvard-Smithsonian Center for Astrophysics have used the Kepler space telescope to measure the rotation rates for stars in a one billion year old cluster called NGC6811 using photometric techniques combined with ground based spectroscopy. The rotation is detected by looking for tiny changes in the brightness of the star caused by spots on its surface rotating in and out of the telescope's sight. They found rotation periods ranging from 1 to 11 days. They will now establish the relationship between stellar rotation and age and measure rotation periods for stars of different masses in star clusters with known ages. With that, measuring the rotation period of any star can determine its age.

For more information: Physicsworld, May 25 (2011); Astrophys. J. Lett., May 20 (2011).

Nanoparticle detection showed using plasmonic sensing:   researchers in LBLN at Berkeley and in the University of Stuttgart have demonstrated how nanoantennae can be used to detect particles and atoms. When the oscillation frequency of the generated surface plasmons matches that of the incident electromagnetic waves, a localized surface plasmon resonance (LSPR) occurs which concentrates the electromagnetic field in a 100 nm³ nanofocus volume. Any object brought into this locally confined field will affect the LSPR. Light scattered by the system can be collected by a dark-field microscope and the change in the LSPR read out in real time. This technique allows for probing biochemical processes using light and without fluorescent markers.

For more information: Physicsworld, May 26 (2011); Nature Materials, May 15 (2011).

WEEK OF MAY 23, 2011 [No. 898]

Sun modulated cosmic ray flow modifies rate of cloud formation:   researchers in Denmark and the UK have shown how cosmic rays (CR) could stimulate the formation of water droplets in the Earth's atmosphere. The close correlation between global temperatures and solar activity cannot be explained by recorded changes to the Sun's brightness (that have a small effect). It is believed that CR's seed low-lying clouds (where ionization radiation is scarce) that reflect some of the Sun's radiation back into space. The number of CR's reaching the Earth is dependent on the strength of the solar magnetic field. When this magnetic field is stronger (larger number of sunspots) more of the CR's are deflected, fewer clouds are formed and so the Earth heats up. When the field is weaker, the Earth cools down. CR's ionize atmosphere molecules that then draw molecules of water vapor to them until the aggregate is large enough to act as a condensing surface. The experiment used 580 MeV electrons from a storage ring irradiated into a gas mixture simulating atmosphere. The production rate of 3-nm clusters was measured to increase significantly. Further experiments are planned to determine whether the clusters grow to ~100 nm to act as cloud-condensing nuclei. This work is the best experimental evidence yet that the Sun influences the climate by altering the intensity of the CR flux reaching the Earth's surface.

For more information: Physicsworld, May 13 (2011); Geophys. Res. Lett., to be published.

WEEK OF MAY 16, 2011 [No. 897]

Fruit flies use viscous drag during flight:   researchers in Cornell University have used cameras at 8,000 frames/s to film fruit flies to note that the wings remained almost horizontal irrespective of flight speed rather than increasing tilt as they flew faster to shift the lift forward. When they wanted to fly quickly they tilted their wings closer to the horizontal on the forward stroke to slice more cleanly through the air and then closer to the vertical on the backward stroke to maximize drag. Wing motions are much closer to the movement of swimming organisms than previously thought, supporting the controversial idea that flight evolved gradually from swimming.

For more information: Physicsworld, May 10 (2011); Phys. Rev. Lett., April 26 (2011) page 178103.

Matchbox-size atomic clock in the market:   Symmetricom sells a 35g atomic clock at $1,500 with a power requirement of 115 mW. Cs atoms are held within a resonance cell and are heated to a vapor state by plates at the top and bottom of the package. A VCSEL laser is shone through the vapor. The laser light is modulated by a microwave signal generator in the chip. This allows the laser single beam to excite the Cs atoms at two different energy levels. Interference between these two levels is then detected by a photodiode that forms part of a feedback loop. The loop optimizes the number of photons absorbed by the Cs atoms. The clock indicates that 1 second has elapsed after counting exactly 4,596,315,885 cycles of the microwave oscillator signal.

For more information: Physicsworld, May 11 (2011).

WEEK OF MAY 9, 2011 [No. 896]

Intel will use 3D transistors in the next step 22-nm chip:   the chip maker Intel plans to change transistors into a vertical, fin-like structure in high-volume production of their next step chips. The fin-like structure rises above the surface of the transistor with the gate wrapped around it, forming conducting channels on three sides. Control of current is accomplished by implementing a gate on each of the three sides of the fin (two on each side and one across the top) rather than just one on top as is the case with the 2-D planar transistor. The additional control enables as much transistor current flowing as possible when the transistor is in the "on" state (for performance) and as close to zero as possible when it is in the "off" state (to minimize power) and enables the transistor to switch very quickly between the two states (for performance). The 22nm 3-D Tri-Gate transistors provide up to 37% performance increase at low voltage vs. Intel's 32nm planar transistors. They consume less than half the power when at the same performance as planar transistors on 32nm chips. The 3-D transistors are a fundamental departure from the 2-D planar transistor that has powered microelectronics for five decades. Designers have the ability to continue growing the height of the fins to get more performance and energy-efficiency gains.

For more information: ScienceDaily, May 5 (2011); Wall Street Journal, May 9 (2011) page B1.

WEEK OF MAY 2, 2011 [No. 895]

Reversible spot self-healing of a loaded polymer using light demonstrated:   a group lead by scientists in Case Western Reserve University have synthesized self-healing metallosupramolecular polymeric materials based on oligomers with short polymer chains with ends terminating with ligands that are non-covalently linked through metal ions ( in this case either Zn or La). When UV light shines on a scratch damaged spot of the polymer where metal-ligand complexes are ruptured, the ligands are excited by absorption of the light's energy, and then relax to their ground states generating heat that releases the metal ion. This softens the surrounding material by depolymerizing the material into a liquid that flows and heals cracks and scratches by reforming the ruptured complexes. When removing the light, the ligands rebind to the metal, polymerizing again and reestablishing the mechanical strength of the material in less than a minute. This photothermal intrinsic healing process is reversible so multiple cycles of scratch and heal are feasible. Since light can be applied locally to a damaged site, objects can be healed under load. Different metal-ligand complexes absorb light at different wavelengths so it should be possible to tune the wavelength at which materials heal by changing the complexes.

For more information: Nature, April 21 (2011) pages 334 and 299; Chem. Eng. News, April 25 (2011) page 8.

WEEK OF APRIL 25, 2011 [No. 894]

Sonoluminescence brightness increased by two orders of magnitude:   scientists in UCLA have broken the record for the brightness of light generated by bubble-bursting sonoluminescence. With a peak power of 100 W, the light is 100 times as bright as seen in previous sonoluminescence experiments. They fill a steel cylinder with phosphoric acid and position it almost a cm above a steel base. Using a needle at the bottom they inject a 1 mm-sized bubble of Xe and let it rise towards the top. When at 11 cm, the cylinder is dropped 1 cm. The resultant shock collapses the bubble in a brief flash of 100 W and a temperature of 10,200 K.

For more information: Physicsworld, April 15 (2011); Physical Review E, to be published (2011).

Nanoarrays built for heterogeneous tandem catalysis:   researchers at UC-Berkeley have designed a class of nanocrystal catalysts that consist of two catalysts stacked on top of each other. They deposited single layers of Pt nanocubes on top of a SiO₂ base. They then added a single layer of CeO₂ nanocubes to form an array of bilayered cubes 6-8 nm on a side. The interface between CeO₂ and Pt catalyzed the decomposition of methanol to CO and H₂. The Pt-SiO₂ interface then catalyzed the reaction of CO and H₂ with ethylene to form propanal. Production is faster than obtained conventionally by starting with CO and H₂ and using a Pt-SiO₂ catalyst.

For more information: Chem. Eng. News, April 18 (2011) page 9; Nat. Chem., to be published (2011).

WEEK OF APRIL 18, 2011 [No. 893]

Internal structure of numerous distant stars probed:   an international team of scientists have used the Kepler space telescope to detect solarlike oscillations in 500 solar-type stars in the Milky Way. The exquisite photometric precision of the telescope makes it the ideal instrument for measuring low-amplitude brightness variations in a broad range of stars. The distribution of the radii of these stars matches that expected from stellar evolution theory, but the distribution in mass does not. The observed mass distribution is wider and shifted toward lower masses. They found more stars with about one solar mass than predicted by present theory. They also report the detection of a triple-star system comprising a red giant star and two red dwarfs. The red giant star, instead of the expected solarlike oscillations, which might be suppressed by the unusual orbital dynamics, shows evidence for tidally induced oscillations driven by the orbital motion of the red dwarf pair. The system is the first of its kind in that it has two different kinds of eclipses, one where the pair and the star eclipse each other and another where the pair eclipses each other. Finally they also provide evidence for the detection of gravity-mode (rather than the usual surface p-modes) period spacing in a red giant star, allowing deep probing of the red giant star structure.

For more information: Science, April 8 (2011) pages 205, 213, 216 and 180; Physicsworld, April 8 (2011).

WEEK OF APRIL 11, 2011 [No. 892]

Precise modulation of polymerization with applied voltage:   scientists at Carnegie Mellon University have achieved a new level of control in atom transfer radical polymerization ATRP, a reaction that is used to make specialty polymers such as adhesives and coatings. By applying specific voltages to an electrochemical cell filled with a solution of catalysts, monomer, and alkyl halide, the scientists are able to turn the polymer formation process on and off at will. The work relies on a type of reaction in which a transition-metal catalyst is used to form C-C bonds. In electrochemically mediated ATRP, conventional chemical reducing agents are eliminated.

For more information: Chem. Eng. News, April 4 (2011) page 10; Science, April 1 (2011) page 81.

Giant Faraday effect discovered:   a group lead by scientists at the Vienna University of Technology, have used an epitaxial HgTe thin film 70 nm thick to rotate linearly polarized THz light by 15° with a magnetic field of 1 Tesla. It is expected that a film 1µ thick will rotate the light > 45°. The lights oscillating electric field causes conduction electrons to drift. When a magnetic field is applied, the electrons rotate. When the rotation of the light is greatest, the electron cyclotron frequency matches that of light, suggesting that this resonance contributes to the giant Faraday effect which is two orders of magnitude larger than measured before.

For more information: Physicsworld, April 4 (2011); Phys. Rev. Lett., March 11 (2011) page 107404.

WEEK OF APRIL 4, 2011 [No. 891]

AIDS virus blocked by engineered protein fragment:   a group lead by scientists of the NIH in Bethesda took a protein apart and removed the portion that causes harm, then stabilized and modified the section that has therapeutic effect. The peptide with high potency against AIDS is based on a naturally occurring protein in the body that protects cells from viruses. The man-made version does not cause inflammation and other side effects at the dosages required.

For more information: ScienceDaily, April 2 (2011); The FASEB J., to be published (2011).

Fly ash used to extend lifespan of concrete structures:   a group lead by researchers at Florida Atlantic University have demonstrated that coating concrete destined to rebuild bridges, highways, and water and waste water systems with some of the ash left over from burning coal in power plants could extend the life of those structures by decades. The new materials can be used to coat and protect from corrosions steel reinforcing bar and for repairing damaged concrete.

For more information: ScienceDaily, March 30 (2011).

Nano-encapsulated antibiotics defeat drug-resistant microbes:   scientists at King Saud University in Saudi Arabia have put common antibiotics inside nanofibers made of polyvinyl alcohol and polyethylene oxide. They were highly effective in killing a variety of disease-causing bacteria and fungi. The microbes were severely damaged. The fiber by themselves, without antibiotic, did not affect the bacteria. They seem to work by boosting the power of the antibiotics.

For more information: ScienceDaily, March 30 (2011).

WEEK OF MARCH 28, 2011 [No. 890]

Synthetic polymer capable of dynamic self-strengthening fabricated:   researchers at Rice University have created a material that gets stronger from repeated stress (similarly to what bones and muscles do after repeated exercise). The group believes that the trick lies in the complex, dynamic interface between nanostructures and polymers in carefully engineered nanocomposite materials. There is very little chemical interaction, if any, between the polymer and the nanotubes. It seems that this fluid interface is evolving during stressing. The development shows the potential of stiffening polymer-based nanocomposites with carbon nanotube fillers.

For more information: ScienceDaily, March 24 (2011); ACS Nano, to be published (2011).

Real-time analysis of conscious animal behavior and brain function:   a group lead by scientists from the BNL at Stony Brook, have demonstrated the efficacy of a wearable PET scanner they have developed for rats to correlate brain function with behavior. They use the tracer 11C-racloride that binds to receptors for dopamine. A higher signal from the tracer means that less natural dopamine is in an area of the brain; a low signal indicates that the area has released dopamine (which binds to receptors, thus blocking the tracer from binding). The mini-PET allows to simultaneously studying brain function and behavior in awake, moving animals.

For more information: Nature, March 10 (2011) pages 177, 183, and 170.

WEEK OF MARCH 21, 2011 [No. 889]

Functional connectome in mammalian brains:   scientists in Harvard University, Carnegie Mellon University and Max Planck -Heidelberg have pioneered an approach to finding rules of connection between neurons that depend on their functional properties as well as their cell type. They have applied the method to the mouse retina and primary visual cortex. They characterized a functional property by imaging the activity of neurons in a functioning network using two-photon microscopy and Ca-sensitive indicators, before mapping their connectivity. Large-scale electron microscopy of serial thin sections was then used to trace a portion of these neurons'local network. The work realized imaged less than 1% of a cubic millimeter of brain volume with 50-60µ in one dimension. Producing a human brain map with thousands of synaptic connections made by each of billions of neurons all related to neuronal function will require image acquisition and data analysis speeds much larger than presently possible. The approach proposed for relating the structure of neural networks to their function is to search for rules of connectivity that depend on functional properties of neurons. Finding those rules will be much harder than finding connections between brain regions, or rules of connections between neuronal cell types.

For more information: Nature, March 10 (2011) pages 177, 183, and 170.

WEEK OF MARCH 14, 2011 [No. 888]

Molecular organic photoreactions induced through surface geometry:   a group lead by UCLA scientists have used defect sites in self-assembled alakanethiolate monolayers on Au surfaces to direct geometrically unfavorable photochemical reactions between isolated and trapped pairs of organic molecules. These are photoreactions of conjugated organic molecules that are allowed by selection rules but not observed in solution reactions because of unfavorable reaction geometries. UV light absorbed during STM imaging increases the apparent heights of excited molecules in STM images, a direct manifestation of probing electronically excited states.

For more information: Science, March 11 (2011) page 1312; ScienceDaily, March 11 (2011).

Surface emitting laser speed increased by a factor of four:   scientists at Chalmers University of Technology have shown that a surface emitting laser (oxide-confined 850 nm VCSEL) can deliver error-free data at a record transmission rate of 40 Gbit/s. They have shown the ability to test the lasers on the wafer before it is cut into chips for assembly. The lasers work directly where they sit on the wafer emitting from the surface of the laser chip. The ability to test up to 100,000 lasers on a wafer reduces the cost of production to one tenth compared with conventional lasers. The energy and power consumption is a tenth of a conventional laser, a few hundred fJ/bit.

For more information: ScienceDaily, March 6 (2011); Electronics Lett., (2010).

WEEK OF MARCH 7, 2011 [No. 887]

Integrated photonic ship operates at 1 Tbit/s:   scientists at Infinera in Sunnyvale have integrated a new 10-channel receiver onto a single 10 x 100 Gbit/s photonic integrated circuit. It contains more than 150 optical components (frequency tunable local oscillator LO lasers, devices for mixing the LO and incoming signals, variable optical oscillators for LO power control, spectral demultiplexer to separate the individual wavelength channels, and forty balanced photodetector receiver-transmitter pairs) all integrated onto a chip smaller than a fingernail.

For more information: ScienceDaily, March 1 (2011).

Blow molding metals developed:   scientists at Yale University have shown that bulk metallic glasses BMGs (metal alloys that have randomly arranged atoms as opposed to the orderly, crystalline structure found in ordinary metals) can be blow molded like plastics into complex shapes. The materials cost about the same as high-end steel but can be processed as cheaply as plastic. The alloys are made up of different metals, including Zr, Ni, Ti an Cu. The material is stronger than steel but as versatile as plastc and able to take an endless variety of shapes.

For more information: ScienceDaily, February 28 (2011); Materials Today, February 14 (2011).

Nanometric optical microscope built:   a group lead by researchers at the University of Manchester have created a microscope with record resolution that beats the diffraction limit. They combine an optical microscope with a transparent microsphere (far field superlense) to reach direct imaging with 50-nm resolution under normal light. The system is based on capturing optical, near-field virtual images, which are free from optical diffraction, and amplifying them using a microsphere with further relay and amplification by a standard optical microcope.

For more information: ScienceDaily, March 2 (2011); Nat. Comm, March 1 (2011).

WEEK OF FEBRUARY 28, 2011 [No. 886]

Super-efficient DNA electron spin filtering discovered:   an international group lead by scientists at Wilhelms Universitat at Munster, have found that 60% spin polarization at room temperature can be achieved by passing free electrons through an Au surface covered with a self-assembled densely packed mono- layer of 80- base-pair long double-stranded DNA (with one end of the strand treated with a sulphur compound to make it stick). They shone a linearly polarized UV laser into the Au surface to get unpolarized photoelectrons emitted and traveling through the DNA forest and moving into a Mott polarimeter to measure their spin. The electrons became polarized (spin parallel to their velocity) by as much as 60%. The polarization is a strong function of the length of the DNA strands, with 25 base-pair long strands only yielding about 10% polarization. The filter does not work when the DNA coverage is random and sparse so the interaction seems to be with the lattice of directionally ordered strands rather than with individual strands. The new filtering effect is near four orders of magnitude stronger than passing the electrons through a vapor of heavy chiral molecules where the filtering is due to spin-orbit coupling. It is about three times more efficient than using magnet-based spin filters that exploit giant-magnetoresistance. The finding reveals a link between chirality and spintronics.

For more information: Science, February 18 (2011) pages 894 and 864; Chem. Eng. News, February 21 (2011) page 34.

WEEK OF FEBRUARY 21, 2011 [No. 885]

Axon-axon communication discovered:   a group lead by scientists at Northwestern University have discovered that axons can operate both by carrying neuron cell body signals away, and in reverse, by sending signals to the neuron cell body. In addition to the typical neuronal communication where an axon of one neuron is in contact with another neuron's dendrite or cell body, axons can perform their own neural computations without any involvement from the cell body or dendrites and axons can talk to each other. Computations occurring in axons are thousands of times slower than in dendrites and cell body. The conventional dendrite integration of synaptic inputs on the milliseconds time scale with action potential (neuron membrane voltage fluctuation) initiation occurring in the axon initial segment is then extended to a slower form of integration that leads to action potential initiation in the distal axon, well beyond the initial segment. Neuronal spikes evoked over minutes resulted in persistent firing that lasted for a similar duration. This neuronal memory is stored in the axon near its end and far from the neuron cell body. Persisted firing was not restricted to the stimulated neuron. Interneurons can slowly integrate spiking, share the output across a coupled network of axons and respond with persistent firing in unstimulated neurons, in the absence of input to their own soma or dendrites. No dendrites or neuron cell bodies were involved in this communication between axons.

For more information: Sciencedaily, February 19 (2011); Nature Neuroscience, December 8 (2010).

WEEK OF FEBRUARY 14, 2011 [No. 884]

Closed circuit of ultracold atoms produced:   scientists at the University of Maryland have created and controlled a current using 300,000 Na atoms at 10nK. They began by laser cooling Na atoms in a beam and capturing a billion of them in a magnetic trap. The strength of the field is then reduced to let the more energetic atoms to bounce out and further cool the remaining atoms. Then the BEC is caught in crossed lasers (one cylindrical and one sheet-like) and the magnetic trap is dropped. They set up a field that collects the atoms in a continuous loop within a flattened doughnut with 20µ radius. To start the rotation they shine two lasers (photons in one carry angular momentum) tuned to force the atoms to absorb photons from one and emit into the other.

For more information: Physicsworld, February 9 (2011); Phys. Rev. Lett., to be published (2011).

Thermal Casimir force measured:   a group lead by scientists at Yale University has measured the attractive force between two close metal surfaces separated by > 3µ (where the force caused by quantum zero-point fluctuations is null) caused by thermal fluctuations of the electromagnetic field. They mounted a flat Au plate on a horizontal beam suspended from its center by a wire to create a torsion pendulum. An Au sphere was brought up slowly to the plate. They measured the electrostatic force to be applied to balance the beam as the sphere is moved near the plate. The measured forces drop with the inverse cube and inverse square of distance before and after 3µ.

For more information: Physicsworld, February 8 (2011); Nature Physics, February 6 (2011).

WEEK OF FEBRUARY 7, 2011 [No. 883]

Structure of biological samples in non-crystalline form imaged:   an international team of scientists have used a hard XR free electron laser in the SLAC laboratory, to flash biological samples (both in crystalline and non-crystalline forms) with intense femtosecond pulses of X-rays before any radiation damage sets in and hence analyze their structures. Nanocrystals of a membrane protein (very difficult to grow into crystals large enough for conventional XR crystallography) are suspended in water jets and exposed to XR pulses to generate a diffraction pattern with 0.85 nm resolution. This allows structure determination of macromolecules that do not yield crystals of sufficient size for studies using conventional XR sources or are too sensitive to radiation damage. A mimivirus (largest known virus with size 450 nm) was also imaged producing a continuous diffraction patterns that was analyzed using an advanced computer algorithm. The ultimate structure resolution reached was 32nm although it is expected that much higher resolutions are possible with shorter and brighter photon pulses focused to a smaller area.

For more information: Nature, February 3 (2011) pages 73 and 78; Physicsworld, February 3 (2011); ScienceDaily, February 4 (2011).

The most distant galaxy yet discovered found:   a group lead by researchers of UCSC in Santa Cruz have used the new Wide Field camera in the reserviced Hubble Space Telescope to conduct an ultra-deep search for z~10 galaxies. They found a galaxy ~500 Myr after the Big Bang in the heart of the reionization epoch, and shown that the star formation rate density is much smaller (~10%) at this time than it is just ~200Myr later at z~8. This shows how rapid galaxy build-up was at z~10, as galaxies increased in both luminosity density and volume density from z~10 to z~8. Galaxies at z~10 may not provide enough UV flux for reionization of the Universe.

For more information: Nature, January 27 (2011).

WEEK OF JANUARY 31, 2011 [No. 882]

Reprogramming of germ cells to make neurons:   scientists in Columbia University have discovered a simple recipe for transforming germ cells into somatic cells in the nematode Caenorhabditis elegans. Their recipe requires only: expression of a transcription factor called CHE-1 that specifies the fate of somatic cells, and loss of a chromatin regulatory factor called LIN-53. This has far-reaching implications for developmental biology and regenerative medicine.

For more information: Science, January 21 (2011) pages 304 and 292.

Ensemble entanglement in a solid-state device demonstrated:   an international team lead by researchers at the University of Oxford has produced qubits by doping a Si crystal with P atoms. With their material at 3 K and 3.4 T, and exposing it to radio and microwave pulses, they were able to create 10¹⁰ pairs of entangled electrons and P nuclei in a spin ensemble. They confirm the entanglement to fidelity of 98% through the emission of microwaves from the Si crystal.

For more information: Nature, January 19 (2011) on line; Physicsworld, January 24 (2011).

Near-real-time telepresence shown:   MIT researchers have demonstrated a dynamic hologram that recreates evolving 3D scenes at 15 fps. They use a commercially available range-finding camera that records both the luminance and depth of a scene. They take the footage and send it via internet to a PC with 3 graphics processing units programmed with an algorithm to compute the diffraction patterns needed to reproduce the moving 3D images. The patterns are recreated on a wafels screen (wafels allow for the control of the intensity of light emitted in all directions).

For more information: Physicsworld, January 25 (2011).

WEEK OF JANUARY 24, 2011 [No. 881]

Electron vortex beams produced:   NIST scientists have produced well-separated electron beams with helical wavefronts carrying large quanta of orbital angular momentum (quantized phase vortices of up to 100ℏ per electron were observed). They used nanofabricated diffraction holograms in an electron microscope to produce multiple electron vortex beams. Twisted electron beams should produce higher-resolution imaging than with conventional TEM because resolution is determined by the beam's spot size, and the central beam is the most difficult to focus. When the used electron beam diffracts in the hologram, it has a singularity in the quantum mechanical phase along the center of the beam (the phase is not well defined). Interference effects cause the central beam intensity to vanish, creating instead a vortex of twisted beams spiraling around this node. The absence of intensity at the beam center can be used to improve the resolution. Because of their charge and their orbital angular momentum, the beams can couple well with electrons, electrostatic charges, and magnetic potentials in the sample so they can improve sample analysis. They are simple to implement by changing the electron source in an electron microscope through insertion of a dislocated hologram into the condenser aperture.

For more information: Science, January 14 (2011) pages 192 and 155; Physicsworld, January 14 (2011).

WEEK OF JANUARY 17, 2011 [No. 880]

In vivo 3D fast high resolution video of neuronal circuit activity:   UCLA scientists have developed a multifocal two-photon microscopy technique with spatio-temporal excitation-emission multiplexing. They modified two-photon laser scanning microscopes to image fluorescent ca dyes inside neurons, split the main laser beam in 4 smaller beamlets, and used another beam to record neurons at different depths. The 3D record was possible at 250 fps.

For more information: ScienceDaily, January 13 (2011); Nature Methods, January 9 (2011).

Black holes seem be there before their galaxies:   researchers at the University of Virginia have examined the intense radio waves and XR emanating from the center of Henize 2-10 (a dwarf galaxy with radius 3% of and 30 M light-years from the Milky Way) and concluded that there is a supermassive accreting black hole in it, with about 1M times the mass of the Sun. This greatly strengthens the case for the black holes developing first, before the galaxy bulge is formed.

For more information: Physicsworld, January 10 (2011); Nature, January 9 (2011).

Sequential femtosecond imaging with microscopic resolution shown:   a group lead by scientists of the Technische Universitat Berlinhas demonstrated a holographic imaging approach capable of recording two fully independent molecular images using a free-electron XR laser with a variable time delay over the femtosecond regime. They used an algorithm to descramble the two images by XR pulses separated by 50 fs encoded simultaneously in a single XR hologram.

For more information: ScienceDaily, January 14 (2011); Nature Photonics, January 9 (2011).

Solid state quantum memory built:   groups at the Universities of Paderbom and Geneva have shown how one photon in an entangled pair can be absorbed by a crystal doped with a rare-earth ion, so that its quantum state becomes stored as an atomic excitation. A fraction of a second later, a new photon is emitted with that entangled state intact. The first group achieved storage time 7 ns , efficiency 2%, and bandwidth 5 GHz comparing to 200 ns, 20% and 125 MHz by the second.

For more information: Physicsworld, January 12 (2011).

WEEK OF JANUARY 10, 2011 [No. 879]

Hot plasma feeding of solar corona observed:   a group lead by scientists of the Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto has used observations from the Solar Dynamics Observatory and the Hinode solar physics mission to reveal an ubiquitous coronal mass supply of chromospheric plasma in the form of fountain like jets or spicules (originated in a thin layer between the photosphere and the corona, and widely across the Sun), is accelerated upward into the corona, with much of the plasma heated between 2 and 10 eV (sinking back down into the chromosphere) and a significant fraction over 100 eV (uplifted into the corona).

For more information: Science, January 7 (2011) page 55; Physicsworld, January 6 (2011); ScienceDaily, January 7 (2011).

Magnetic domains imaged in 3D for the first time:   a European group lead by scientists of the Institute of Applied Materials in Berlin have used the Talbot-Lau neutron tomography technique to directly image the 3D network of magnetic domains (where all magnetic moments point in one direction) within the bulk of FeSi crystals. A coherent beam of low-energy neutrons is fired at the sample. A small number of neutrons are deflected slightly when they cross a boundary between two domains due to the abrupt change in the index of refraction. A diffraction grating with a detector behind it is scanned across the beam of deflected neutrons to get the deflection angle.

For more information: Physicsworld, January 5 (2011); Nature Comm., November 23 (2010).

WEEK OF JANUARY 3, 2011 [No. 878]

Protein set responsible for neuron dendrite microtubule polarization discovered:   scientists at Penn State University, have studied dendrites in vivo on fruit fly nerve cells (similar to human nerve cells) including the lay out of the microtubules, where the raw building materials in the cell's construction flow. In axons the growing ends of the microtubules point away from the cell body whereas in the dendrites point towards the cell body. The microtubules grow constantly and are key in the neuron organization to last a lifetime and in neuron regeneration after injury. They identified the polarization proteins, which include the motor protein kinesin-2. Without them microtubules become disorganized and loose capability for regeneration in response to injury (including flipping polarity when a new axon has to be generated starting from a dendrite).

For more information: ScienceDaily, January 1 (2010); Current Biology, December 21 (2010).

Initial epoch of fast growth of black holes identified:   an international team lead by researchers of the Tel Aviv University has used telescopes in Hawaii and Chile to show that the era of the first fast growth of the most massive black holes that were active when the Universe was 1.2 Byrs old lasted 100 - 200 Myrs. Those black holes were about 10-1000 times the mass of the sun, ten times smaller, but growing much faster, than the most massive black holes of later times.

For more information: ScienceDaily, December 28 (2010); The Astrophysical Journal, to be published (2010).

NOTE: previous Research News (since WEEK OF MARCH 1, 1994 [No. 1], around the time when the Quantum Cascade Lasers were demonstrated at AT&T Bell Laboratories in Murray Hill, N.J., as promising MIR solid-state room temperature sources that would enable laser spectroscopy in the spectral region where fundamental rotational-vibrational transitions of most molecules take place) not posted.