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2005

June

Nanoparticles: NO-Releasing Gold Nanoparticles
(Chemical & Engineering News)
Gold nanoparticles designed to release nitric oxide in controlled amounts have been developed. This could be useful for a range of biomedical and pharmaceutical applications.
(6.30.05)

Micromanipulation: Magnetic nanoparticles used to move microscopic objects
(Nature Materials Update)
Magnetic nanoparticles were used to shepherd tiny objects around on a surface. The technique provides a new means of micromanipulation, and could be used to build microstructures for electronics or to ferry cells around in biomedicine.
(6.30.05)

Magnetism: Magnetic surprise for liquid metals
(PhysicsWeb)
Researchers have found that some liquid metals which appear to be non-magnetic actually contain magnetic moments that appear and disappear on extremely short time scales. The phenomenon is thought to be caused by a phenomenon called cage diffusion
(6.30.05)

Courtesy Majumdar & Yang labs, U. Cal.
Microfluidics: Researchers create microfluidic transistor
(Univ. California, Berkeley)
The first "nanofluidic" transistor has been created that allows for the control of the movement of ions through sub-microscopic, water-filled channels. Such transistors could anchor molecular processors allowing for microscopic chemical plants on a chip.
(6.29.05)

Nanotribology: Friction, adhesion change at atomic level
(Johns Hopkins U.)
New modeling shows that surfaces from a few to a thousand atoms across, with the same shape, but with different local structures, or "bumps," behave quite differently, even if those surfaces are made of the same material. Local stresses and adhesion forces can vary by a factor of two or more, and friction can change tenfold.
(6.29.05)

Biological Materials: Highly conductive biological nanowires discovered
(Univ. Massachusetts, Amherst)
A tiny biological nanowire structure that is highly electrically conductive has been discovered. The conductive structures, termed “microbial nanowires,” are produced by a novel microorganism known as Geobacter . They are only 3-5 nanometers in width but quite durable and more than a thousand times long as they are wide.
(6.28.05)

High-K Dielectrics: Hafnium compounds are leading contenders for high-k dielectrics
(Chemical & Engineering News)
Hafnium-containing compounds are currently the leading contenders for next generation high-k dielectrics. High-k materials will function as the gate insulator, a thin layer in the transistor that separates the gate from the channel through which the current flows.
(6.28.05)

Nanorods: Nanorods act as localized heaters
(Nature Materials Update)
Nanoscale gold rods have been shown to act as 'bar heaters' that convert light efficiently into heat. When the wavelength of incident laser light came into resonance with the excitation frequency of the nanorods, the temperature of the rods rose to over 100°C at room temperature. Without the nanorods, heating by the laser was negligible. Also, the nanorods showed a much stronger effect than nanospheres.
(6.24.05)

Archeology: Ancient Egyptians shown to manufacture glass
(Science News)
Archaeological finds indicate that by about 3,250 years ago, Egypt had become a major glass producer and was shipping the valuable material throughout the region for reworking by local artisans.
(6.24.05)

© University of Pennsylvania
Biological Materials: Mechanical properties of blood clot fibers measured
(University of Pennsylvania)
Blood clots are a 3-D network of fibrin fibers, stabilized by a different protein. The mechanical properties of an individual fiber in a blood clot have now been measured using “laser tweezers”.
(6.23.05)

Sol-Gel Technology: Method reversibly gelatinizes a range of liquids
(New Scientist)
A method has been devised to reversibly gelatinise a range of liquids. A compound made of small organic molecules containing palladium was dissolved in acetone to produce a transparent, oily solution that was then blasted with ultrasound waves at a frequency of 40 kilohertz. After just 3 seconds, it formed an opaque white gel. A blast of heat changed the gel back to a liquid.
[(Jour. American Chemical Society, DOI: 10.1021/ja050809h)]
(6.23.05)

Cell Functions: Inner structure of cells behaves much as molten glass
(Harvard University)
It has been found that the cell modulates its mechanical properties in much the same way as a glassblower shapes glassware. Experiments show that the cell is a strange intermediate form of matter that is neither solid nor fluid, but retains features of both.
(6.22.05)

Excitons: 'Heavy photons' sent over world-record distances
(Eurekalert)
When light hits a semiconductor material and is absorbed, its photons can become excitons. A two-dimensional semiconductor structure has now been designed and demonstrated in which excitons exist longer and travel farther than previously recorded. This open up the possibility of new applications such as excitonic circuits.
(6.22.05)

Tissue Engineering: Tissue engineered viable, vascularized 3D muscles implanted
(MIT)
The lack of an internal, nourishing blood system in engineered tissues has been a major issue. Now, researchers have been able to coax muscle tissue to develop its own vascular network, a process called pre-vascularization.
(6.21.05)

LEDs: Multicolor emission from nanocrystal light-emitting diodes demonstrated
(Nature Materials Update)
For multicolor LEDs, a different material system is normally needed for each specific color. Efficient multicolor light emission from LED structures using nanocrystal layers has now been demonstrated using CdSe/ZnS nanocrystals sandwiched between layers of conventional GaN.
[Mueller A. H. et al., Nano Letters, 5, 1039 (2005)]
(6.21.05)

Nanotubes: Nanotube bristles give brushes unique properties
(Chemical & Engineering News)
Microscale brushes featuring carbon nanotube bristles have been created. A partially masked silicon carbide fiber was used for the brush's core and then nanotubes were grown onto unmasked areas via CVD.
(6.17.05)

Superconductors: Superconducting nanowires pulse to a new beat
(PhysicsWeb)
A quantum interference device has been created by coating a pair of DNA molecules with superconducting material (an alloy of molybdenum and germanium). The resulting two-nanowire device showed unusual resistance oscillations in an applied magnetic field
[Science 308 1762]
(6.17.05)

Spintronics: New method for controlling and measuring electron spins in GaAs
(Los Alamos National Lab)
A novel method has been developed for controlling and measuring electron spins in semiconductor crystals of GaAs. The work suggests an alternative method of spin manipulation for future generations of semiconductor spintronic devices.
(6.16.05)

Tissue Engineering: Microscopic scaffolds may help regenerate cells
(NIBIB, NIH)
New innovative scaffolds are under development to jumpstart cell regeneration that can transport molecular signals directly to ailing cells. The synthetic scaffolding alters cellular behavior and may eventually provide a means to regenerate damaged neurons and restore junctions between nerve fibers lost in paralysis.
(6.16.05)

Molecular Electronics: Molecular logic gate operates in membrane nanospace
(Chemical & Engineering News)
A fluorescent molecule has been designed that carries out a logical computation in the nanospace of a membrane. The system operates as a two-input AND logic gate, in which two conditions must both be satisfied to produce an output.
[J. Am. Chem. Soc. 2005, 127, 8920]
(6.16.05)

Drug Delivery: Light pumps drugs from nanoparticles
(Nature Materials Update)
Nanoscale packages from which drug molecules can be released in controlled pulses using light have been developed. A flash of ultraviolet light changes the shape of molecules in the walls of the nanocompartments where the drug is held, apparently opening up pores that let the drug leak out. A flash of visible light converts the molecules back again, sealing the openings.
(6.15.05)

Polymorphism: New polymorph in colloidal crystals
(Nature Materials Update)
A new study shows that in a colloidal crystal made of PdSe and Pd nanoparticles, a cuboctahedral structure and an icosahedral structure, with different packing densities, can coexist.
(6.15.05)

Nanotubes: Carbon nanotubes made from grass
(PhysicsWeb)
A new method for making multiwalled carbon nanotubes by heating grass in the presence of oxygen has been demonstrated. The nanotubes were about 1 micron long and 30 to 50 nm in diameter.
[Nanotechnology 16 1192]
(6.13.05)

Polymers: Dendrimers branch out
(Chemical & Engineering News)
Dendrimer research has been slowly but steadily gaining ground since the late 1970s when the first of these branching molecules were synthesized. Dendrimers and dendritic polymers now playing key roles in new technologies.
(6.13.05)

Amorphous Alloys: Glass-like metal performs better under stress
(Physical Review Focus)
By adding just the right amounts of aluminum atoms to a copper-based alloy, a group has now produced the first amorphous material that gets harder under stress. A different group has developed a cerium-based material that can be molded in hot water--at less than 100 degrees .
[ Jayanta Das, Mei Bo Tang, Ki Buem Kim, Ralf Theissmann, Falko Baier, Wei Hua Wang, and Jürgen Eckert Phys. Rev. Lett. 94 , 205501 (issue of 27 May 2005); B. Zhang, D. Q. Zhao, M. X. Pan, W. H. Wang, and A. L. Greer
Phys. Rev. Lett. 94 , 205502
(issue of 27 May 2005)]
(6.10.05)

Porous Materials: No need for pores?
(Science - Editor's Choice)
It is usually assumed that molecular diffusion through solid materials proceeds by means of pores that are wide enough to allow passage of molecules. It has now been shown that water can diffuse through seemingly nonporous calixarene crystals.
[Angew. Chem. Int. Ed. 10.1002/anie.200500749 (2005)]
(6.10.05)

Biomimetics: Database of "Biological patents" created
(Economist)
Technologists are increasingly borrowing ideas from nature. A database of “biological patents”. has now been created that will let anyone search through a wide range of biological mechanisms and properties to find natural solutions to technological problems.
(6.10.05)

Fuel Cells: Propane powers fuel cells
(PhysicsWeb)
A micro-sized solid oxide fuel cell that runs on propane has been developed. It has a power output of 350 mW from a 1.42 cm2 surface area, a power density many times higher than for traditional batteries.
[Nature 435 795]
(6.9.05)

Nanoprinting: Nanoprinter could mass-produce nano-devices
(MIT)
A new printing method, called Supramolecular Nano-Stamping (SuNS), has been developed. Single strands of DNA essentially self-assemble upon a surface to duplicate a nano-scale pattern made of their complementary DNA strands. This increases print output exponentially while enabling the reproduction of very complex nano-scale patterns.
(6.9.05)

Fluorescence Spectroscopy: New law allows for unlimited optical resolution in fluorescence microscopy
(science.bio.org)
Researchers have succeeded in overcoming the law postulated by Ernst Abbe in 1873 for diffraction limited resolution in light microscopes. They have established a new law that promises unlimited resolution in fluorescence microscopy.
(6.7.05)

Nanoparticles: Researchers strike gold in cancer detection
(science.bio.org)
A unique method of detecting cancer has been developed using gold nanoparticles. The gold nanoparticles that were bound to a specific antibody displayed a 600 per cent greater affinity for cancer cells than for noncancerous cells.
(6.7.05)

Metamaterials: Putting the reins on light
(Physical Review Focus)
A series of metal strips, with gaps between them, can act somewhat like a uniform slab of glass, except that the speed of light depends on the dimensions of the strips rather than on the material. By narrowing the gaps, a structure that slows light much more than any conventional material can be created.
[J. T. Shen, Peter B. Catrysse, and Shanhui Fan, Phys. Rev. Lett. 94 , 197401, (issue of 20 May 2005)]
(6.7.05)

Molecular Electronics: Charge state of surface ion regulates current flow through nearby molecule
(Chemical & Engineering News)
A new way to control the flow of electrical current through individual molecules has been discovered. A single point charge, such as a surface-bound ion, has been shown to generate an electrostatic field that can be exploited to regulate electrical conductivity in nearby surface-attached molecules. By controlling the charge state of the ion or its spatial relationship to a nearby molecule, the molecule's conductivity can be switched on and off.
[Nature 2005, 435, 658]
(6.6.05)

DNA: Layered nanotubes composed almost entirely of DNA created
(Chemical & Engineering News)
The first layered nanotubes composed almost entirely of DNA have been created. The layers of DNA in the nanotubes are held together by hybridization of a series of DNA strands which fall apart when heated, releasing single-stranded DNA.
[J. Am. Chem. Soc., published online May 25, dx.doi.org/10.1021/ja042343t].
(6.6.05)

Magnetism: Oxygen loses its magnetism under pressure
(PhysicsWeb)
Solid oxygen is the only elementary molecular magnet known. At atmospheric pressure, it is an anti-ferromagnetic insulator but becomes a superconductor and metal at about 96 gigapascals. It has now been experimentally shown that long-range magnetic order completely disappears at about 8 gigapascals, which is far below the insulator-metal or superconductor transition.
[I Goncharenko 2005 Phys. Rev. Lett. 94 205701]
(6.6.05)

Phase-Change Materials: Superfast atom shuffling inspires data-storage alternatives
(Science News Online)
Researchers are striving to recast electronic memory chips by taking advantage of phase-change materials. Rather than accumulating electrons to store data, these upcoming chips instantly toggle patches of atoms between order and disorder. The material can switch with lightning speed between arrangements that have dramatically different optical properties or electrical resistances
(6.6.05)

Polymers: Solving the hopping problem in semiconducting polymers
(Nature Materials Update)
A unified theoretical description of the charge-carrier mobility in disordered semiconducting polymers has been established, which is in excellent agreement with experimental measurements. At room temperature, mobility was found to be mainly determined by the carrier density, but at low temperatures and high electric fields, the field dependence becomes important.
[Pasveer W et al. Unified description of charge-carrier mobilities in disordered semiconducting polymers. Phys. Rev. Lett. 94, 206601 (2005)]
(6.3.05)

Microscale Measurements: Shadow technique improves measurement of micro-holes
(Eurekalert)
A new measurement method uses the shadow cast by a small glass probe to infer the dimensions of microscale holes or other micrometer-sized components. The technique may provide an improved quality control method for measuring the interior dimensions various precision-engineered products.
(6.2.05)

© NASA/JPL/ASU
Planetary Geophysics: Martian methane could come from Olivine
(Nature News)
Geologists have calculated that methane that likely exists in the Martian atmosphere could come from the mineral Olivine rather than from a bacterial source. The presence of Olivine has been shown on the Martian surface.
(6.2.05)

May

Biomimetics: Marine sponge yields nanoscale secrets
(Bio.com)
A method has been developed for coupling small, inexpensive synthetic molecules (that duplicate those found at the active center of the bio-catalyst of the marine sponge) onto the surfaces of gold nanoparticles. When two populations of these chemically modified nanoparticles, each bearing half of the catalytic site, are brought together, they function just as the natural biological catalyst does to make silica at low temperatures.
(5.31.05)

PZT: Single-crystal-like PZT formed
(Eurekalert)
Researchers report a new and relatively easy method for the formation of "single-crystal-like" PZT. The material bridges the gap between real single crystals and the typical randomly oriented ceramics. The properties of this new material approach those of true single crystal PZT.
(5.31.05)

Catalysis: New photocatalyst is driven by visible light
(Chemical & Engineering News)
A new sulfide photocatalyst has been shown to induce water to generate hydrogen in the presence of visible light. A solid solution of zinc sulfide, copper indium sulfide, and silver indium sulfide was shown to be a highly active photocatalyst when loaded with ruthenium. [Angew. Chem. Int. Ed., published online May 6, http://dx.doi.org/10.1002/anie.200500314].
(5.27.05)

Photonics: Spontaneous improvements on the horizon
(PhysicsWeb)
It has been shown that the spontaneous emission of light in photonic crystals can be manipulated. Scientists have now demonstrated a way to both reduce spontaneous emission and extract it as useful light.
[Science, 308, 1296]
(5.27.05)

Solid-State Lighting: Solid-state lighting sources get more energy efficient and smart
(Rensselaer Polytechnic Institute)
The ability to control basic light properties — including spectral power distribution, polarization, and color temperature — has been shown for solid-state lighting. This will allow “smart” light sources to adjust to specific environments and requirements and to undertake entirely new functions that are not possible with incandescent or fluorescent lighting.
(5.27.05)

Lithographic Printing: Precise printing of bacteria on solid surfaces demonstrated
(New Scientist)
The world's first bacterial printing press has been demonstrated. The press prints live bacteria onto solid surfaces in precise patterns using photolithographic techniques. This could help explain how bacteria influence each other spatially.
(5.26.05)

Perovskites: Designer magnetic ferroelectric
(Nature Materials Update)
High-pressure synthesis has been used to form a compound — Bi₂NiMnO₆ — that has both ferromagnetic and ferroelectric properties. This material has great potential because if the direction of magnetization of a device can be switched by the use of an electric field, this would reduce the thermal power needed for magnetic memory.
[Azuma M. et al., Journal of the American Chemical Society, published online 14 May 2005]
(5.26.05)

Solitons: 2-dimensional solitons on the surface of magnetic fluids
(Physical Review Focus)
A magnetic field has been shown to be able to sustain an isolated hump on the surface of a soup of magnetic nanoparticles. Among pattern forming systems, it's the first example of a solo feature that does not require the continuous input of energy that normally prevents such features from falling apart.
[Reinhard Richter and I.V. Barashenkov, Phys. Rev. Lett. 94, 184503, (issue of 13 May 2005)]
(5.26.05)

Oxygen from Moondust: NASA offers prize for extracting oxygen from lunar rock
(Nature News)
NASA and the Florida Space Research Institute are offering a prize of a quarter-of-a-million dollars for building the first device, within certain weight and power limits, that can extract at least five kilograms of oxygen from a sample of volcanic ash (a substitute for lunar soil) in the space of eight hours.
(5.24.05)

Biomolecules: Amino acids meet electronics
(PhysicsWeb)
Researchers have studied how different peptides -- each containing between eight and ten amino acids -- adhered to different materials including five metals (gold, palladium, platinum, titanium and aluminium), two semiconductors (gallium arsenide and aluminium gallium arsenide) and two insulators (silicon nitride and silica). They found that, in general, peptides chains with side groups that had an electric charge adhered more strongly than those that were uncharged.
[R. L. Willett et al., Proc. Natl. Acad. Sci. USA, 10.1073 /pnas.0408565102 ]
(5.24.05)

© Boston College
Polymer Microstructures: Microscopic polymeric structures fabricated on a human hair
(Boston College)
Scientists have demonstrated the fabrication of microscopic polymeric structures on top of a human hair, without harming it. They used a technique called multiphoton-absorption photopolymerization (MAP) for this.
(5.24.05)

Nanoparticles: Gold nanoparticles emit light strong enough to view single nanoparticles
(Eurekalert)
Gold nanoparticles were demonstrated to induce light emission strong enough to make it possible to observe a single nanoparticle. Researchers coaxed the particles into strong emission of visible light using a technique called multiphoton absorption induced luminescence (MAIL).
(5.23.05)

Photonics: Modulating a beam of light with electricity
(Cornell University)
Researchers have developed a silicon device that allows an electrical signal to modulate a beam of light on a micrometer scale. The modulator uses a ring resonator -- a circular waveguide coupled to a straight waveguide carrying the beam of light to be modulated. The ring used was 12 microns in diameter to resonate with laser light at a wavelength of 1,576 nanometers, in the near infrared.
(5.23.05)

Data Storage: Dots for data storage
(PhysicsWeb)
A new way to double the storage capacity of magnetic recording devices has been reported. This is made possible by combining arrays of magnetic dots with multiple magnetic layers.
[M Albrecht et al. 2005 J. Appl. Phys. 97 103910]
(5.20.05)

Nanoparticles: Color-changing nanoparticles offer a golden ruler for molecules
(Science)
Researchers report a new method to use pairs of gold nanoparticles to measure distances out to 70 nm between molecules and keep track of their targets indefinitely. This has significant potential for being able to monitor the nanoscale movement of biomolecules.
(5.20.05)

© NIST
Femtosecond Laser: First ultraprecise UV 'Ruler' sizes up atomic world
(NIST)
The world's most accurate "ruler" made with extreme ultraviolet light has been built and demonstrated with ultrafast laser pulses. The new device generates pulses of light lasting just femtoseconds in the ultraviolet region of the electromagnetic spectrum and could become an important tool for ultraprecise measurements.
[R.J. Jones, K.D. Moll, M.J. Thorpe, and J. Ye. 2005. Physical Review Letters. May 20]
(5.19.05)

Fullerenes: Fullerene nanocrystals toxic to bacteria
(Nature Materials Update)
C₆₀ forms nanoscale crystals in water that can inhibit the growth of bacteria. When dispersed in an organic solvent and then mixed with water, C₆₀ aggregates into faceted crystals that may remain in solution for many weeks. The fact that these nanocrystals can be cytotoxic to bacteria adds to previous concerns about the health hazards of fullerenes.
(5.19.05)

LEDs: Scientists develop novel multi-color light-emitting diodes
(Los Alamos National Laboratory)
Researchers have developed the first completely inorganic, multi-color light-emitting diodes (LEDs) based on colloidal quantum dots encapsulated in a gallium nitride (GaN) semiconductor. The work represents a new "hybrid" approach to the development of solid-state lighting.
(5.18.05)

Diamonds: Very large diamonds produced very fast
(Eurekalert)
Researchers have been able to produce 10-carat, half-inch thick single-crystal diamonds at rapid growth rates (100 micrometers per hour) using a chemical vapor deposition (CVD) process. This size is approximately five times that of commercially available diamonds produced by the standard high-pressure/high-temperature method and other CVD techniques.
(5.17.05)

Biomaterials: Novel peptide selectively binds to a conducting polymer
(PhysOrg)
Researchers have identified a protein that could perform the unusual feat of attaching to polypyrrole, a synthetic conducting polymer that has shown promise in biomedical applications. When the peptide was linked to a smaller protein piece that human cells like to attach to, polypyrrole gained the ability to attach to cells grown in flasks in the laboratory.
[A. SANGHVI et al, Nature Materials AOP]
(5.17.05)

Magnetic Levitation: Cryogenically enhanced magneto-Archimedes levitation demonstrated
(New Scientist)
The densest materials known have been made to levitate on a pool of liquid air. A mixture of about 80% liquid nitrogen and 20% liquid oxygen was shown to provide enough buoyancy to lift the densest known material, osmium.
[A T Catherall et al 2005 New J. Phys. 7 118]
(5.16.05)

Biomedical Coatings: New coating could give medical implants a longer life
(Eurekalert)
By mimicking an adhesive protein secreted by mussels and a polymer that repels cells and proteins, researchers have designed a new two-sided coating that sticks securely to a surface and prevents cell and protein buildup, and works for a long period of time.
(5.16.05)

Nanoparticles: Gold-coated tumors make detection easier
(Science Daily)
Scientists are studying ways to bind gold nanoparticles and cancer antibodies to highlight tumors and make them easier to find. The cancer antibodies seek out and bind with a specific protein which is present on the surface of many cancer cells.
(5.16.05)

Bio-Nanotechnology: Vaults: From Biological Mystery to Nanotech Workhorse?
(National Science Foundation)
Naturally occurring nano-capsules, known as "vaults," could provide a whole new class of delivery vehicles for therapeutic drugs and DNA, according to recent research. Vaults could likely be used for a wide range of applications in nanotechnology. However, it is not clear how nature itself uses them.
(5.16.05)

Spintronics: Spintronics under control?
(Nature Materials Update)
Researchers report a fast and efficient process that can be used to create and manipulate spin textures and currents. They propose a hybrid of superconductors (SCs) and diluted magnetic semiconductors (DMSs) to manipulate the local spin and charge textures formed in the DMS by the magnetic flux bundles (vortices) penetrating the SC when in a magnetic field.
[Berciu M., Rappoport T. G. & Jankó B., Nature 435, 71–75 (2005)]
(5.13.05)

Nanocrystalline Metals: Nanobubbles cause metal fatigue
(Nature Materials Update)
Nanocrystalline metals are susceptible to fatigue more so than microcrystalline metals. Simulations have now been performed and they show that nanovoids at grain boundaries may be responsible.
[Farkas D., Willemann M. & Hyde B., Physical Review Letters 94, 165502 (2005)]
(5.12.05)

Liquid Sodium: Room temperature liquid sodium
(Physics News Update)
The most dramatic case yet seen of a “negative melting curve”, similar to water, has been studied for sodium. At a pressure of a million atmospheres sodium melts at room temperature. The liquid is denser than the solid and might have strange plastic or mechanical properties.
(5.12.05)

DNA: Melting into Our Genes
(Physical Review Focus)
Human genes contains stretches of "junk DNA," that serves no obvious biological purpose. Now, computer studies show that many of these useless "introns" lie between chunks of gene that melt at slightly different temperatures. The results suggest that thermodynamics, not just the specific lettering of the genetic code, might determine where the introns appear in our genes. Biologists have expressed skepticism.
[Enrico Carlon, Mehdi Lejard Malki, and Ralf Blossey, Phys. Rev. Lett. 94, 178101
(issue of 6 May 2005)]
(5.12.05)

Atomic Force Microscopy: Microscopes reach new depths
(PhysicsWeb)
Physicists in China have made a new type of AFM that works with samples immersed in a liquid. The device could be used to image biological samples, materials that are easily oxidized and samples in hazardous environments.
[ D Zhang et al. 2005 Rev. Sci. Instrum. 76 053705]
(5.12.05)

Batteries: Silicon solution could lead to a truly long-life battery
(PhysOrg)
Researchers have created a porous-silicon diode that may lead to improved betavoltaics. Such devices convert low levels of radiation into electricity and can have useful lives spanning several decades.
(5.11.05)

Polymers: Designer agents control crystal growth and physical properties of polypropylene
(Chemical & Engineering News)
A new family of "designer" nucleating agents--substituted 1,3,5-benzenetrisamides--have been found to selectively and efficiently nucleate the growth of different crystal structures of isotactic polypropylene, imparting drastically improved physical properties.
[Macromolecules 2005 38, 3688]
(5.9.05)

Surface Bonding: Study blurs the line between thermal and electronic processes in desorption
(Chemical & Engineering News)
A new study indicates that conventional descriptions of the way chemical bonds at surfaces are formed and broken may need to be reevaluated. In the case of a bromine-coated silicon crystal, low-energy thermal vibrations of atoms in the lattice (phonons) can pool their energy and excite an electron at the Si-Br interface into an antibonding state, thereby breaking a bond and causing bromine to desorb.
[Surf. Sci., published online April 14, dx.doi.org/10.1016/j.susc.2005.03.053]
(5.9.05)

Granular Materials: Shake and stir to make granular materials change phases
(Duke University)
In an experiment originally planned for the International Space Station, physicists have devised a controlled, measurable method to make a container of granular material "freeze" into the equivalent of a solid-state crystal, or "melt" into the equivalent of a fluid, by alternating the rates that the beads are stirred or shaken.
[Physical Review Letters (2005)]
(5.9.05)

Refrigeration: Solid-state refrigerator works by removing hot electrons from its periphery
(Nature Materials Update)
Scientists have developed a relatively simple metal – insulator – superconductor (MIS) device that can operate at temperatures of just a few hundred millikelvin. The device works by allowing only hot electrons in a metal to tunnel across a thin insulating junction between it and a superconductor.
[Applied Physics Letters 86, 173508 (2005)]
(5.6.05)

Batteries: Shrinking dimensions spur research into ever-slimmer batteries
(Science)
Researchers around the globe are scrambling to come up with novel materials and designs for two-dimensional batteries to power ever-thinner electronic devices.
(5.6.05)

Optics: Lens makers go flat out
(PhysicsWeb)
Researchers have created a liquid-crystal lens with a focal length that can be adjusted by applying a voltage. The lens, which is flat, was formed by adding a small amount of a light-sensitive monomer to a liquid crystal in a commercially available electro-optic cell and irradiating it with a laser beam.
[J. Appl. Phys. 97 103101(2005)]
(5.5.05)

Glasses: Neutrons reveal first signs of long-range order in glass
(PhysicsWeb)
Physicists have observed previously unseen long-range ordering in glass.The ordering was observed in two very different glassy materials, which suggests that it could be a common feature of all glasses.
[Nature 435 75 (2005)]
(5.5.05)

Microfluidics Sensor: Chip gauges cell reactions
(Technology Research News)
A microfluidics-based sensor has been developed to quickly test the reactions of biological cells to all types of stimuli. The sensor is a silicon wafer with a 1.5-mm-wide, 15-micron-deep channel that connects a pair of chambers.
(5.4.05)

© SV Kalinin/ORNL
Piezoresponse Force Microscopy: Electromechanical microscope nudges the nanoscale
(PhysicsWeb)
Piezoelectricity is an intrinsic property of biological systems and is most pronounced in biomaterials that contain arrays of proteins or polysaccharides. A group of scientists has now used this piezoelectric effect to produce the most detailed images until now of the internal structure of human teeth.
[S V Kalinin et al. (2005) arXiv.org/abs/cond-mat/0504232]
(5.3.05)

DNA Structure: Crystallographic map of DNA structure and conformation created
(Bio.com)
Researchers have made a significant new advance in determining the structure of all possible DNA sequences. They used X-ray crystallography to determine the three-dimensional structures of nearly all the possible sequences of a macromolecule, and thereby create a map of DNA structure.
[Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0409455102]
(5.3.05)

Single Molecule Detection: Molecules queue up to be detected
(Nature Materials Update)
A device for channelling molecules into a narrow passage, where they can be detected using single molecule fluorescence has been developed. The researchers cut a channel 5–10 microns deep and 40 microns wide in a silicon wafer. This channel guided a tiny volume of sample past the laser beam used for detection. Also, the molecules or particles in the sample solution were focused even more tightly using metal electrodes.
[Wang T.-H., Peng Y., Zhang C., Wong P. K. & Ho C.-M., J. Am. Chem. Soc. 127, 5354–5359 (2005)]
(5.2.05)

April

Hydrophobicity: Slippery when dry
(Science Now)
Scientists have created a fluorine-containing polymeric coating material that is hydrophobic when dry but repels water once wet. When water touches the material, the polymer side chain rearranges, exposing the hydrophobic fluorine-containing groups to the surface and causing it to repel water.
[Langmuir, 21 (9), 3742 -3745, 2005. 10.1021/la050357m S0743-7463(05)00357-4]
(4.29.05)

Nanowires: High-speed integrated nanowire circuits created
(Eurekalert)
Researchers have made robust circuits from minuscule nanowires that align themselves on a chip of glass during low-temperature fabrication, creating rudimentary electronic devices that offer solid performance without high-temperature production or the use of silicon.
(4.28.05)

Nanolithography: Innovative fountain pen writes on the nanoscale
(Science Daily)
Researchers have demonstrated writing at the sub-100 nanometer molecular scale in fountain-pen fashion. They developed a novel atomic force microscope (AFM) probe chip with an integrated microfluidic system for capillary feeding of molecular ink. They have named the instrument the Nanofountain Probe (NFP).
(4.28.05)

Fusion: Fusion seen in table-top experiment
(PhysicsWeb)
Physicists in the US have generated nuclear fusion in a simple, table-top device operating at room temperature. The device causes two deuterium nuclei to collide with each other and generate alpha particles, neutrons and energy. The device could have applications as a portable neutron generator or in the propulsion systems for miniature spacecraft, but will not be useful as an energy source because it consumes more energy than it produces.
[Nature 434 1115]
(4.27.05)

Colossal Magnetoresistance: Living on the edge
(Physical Review Focus)
A research team reports significantly lowering the magnetic field needed to dramatically change the resistance of a material that has so far been impractical for devices. The new detection scheme is based on colossal magnetoresistance.
[M. Tokunaga, H. Song, Y. Tokunaga, and T. Tamegai, Phys. Rev. Lett. 94 , 157203 (issue of 22 April 2005)]
(4.27.05)

Photonic Structures: Properties of photonic structures tuned with sound
(Nature News)
Photonic structures are static; their optical properties cannot be changed once they have been produced. Scientists now demonstrate the formation of a dynamic optical superlattice induced by acoustic phonons in a photonic microcavity.
[ de Lima M. M., Hey R., Santos P. V. & Cantarero A, Phys. Rev. Lett. 94, 126805 (2005)]
(4.27.05)

Nanocrystalline Diamond: Ultrananocrystalline diamond shows excellent tribological properties
(Nature Materials Update)
Researchers have measured the frictional properties of thin films of 'ultrananocrystalline' diamond (UNCD) grown from carbon-rich gas. They find that this material can have tribological properties similar to that of 'single-crystal' diamond.
[Sumant A. V. et al. Adv. Mater. 17, 1039–1045 (2005)]
(4.27.05)

© Max Planck Inst. Metals Res./ESRF)
Crystalline Structure: Living metals
(Press Release: Max Planck Institute for Metals Research, Stuttgart/European Synchrotron Radiation Facility)
Using Synchrotron x-ray microbeams, a research team has been able to observe for the first time that the microscopic structure of an Fe-Al crystalline material fluctuates with time.
(4.25.05)

Microlenses: Telescopes make bug-eye optics
(Technology Research News)
Similar to insects' compound eyes, researchers have developed a prototype artificial compound eye made from three stacked sets of microlenses that form an array of tiny telescopes.
(4.25.05)

Shape-Memory Polymers: Ultraviolet shifts plastic's shape
(Technology Research News)
Researchers have created a polymer material that can be switched from one shape to another in the presence of the right wavelengths of ultraviolet light. The material is a mix of two polymers. The first forms the material's original shape, and the second forms cross-links in the presence of ultraviolet light longer than 260 nm.
(4.25.05)

© PhysicsWeb/Science
Negative-Refractive Index Materials: Superlens breakthrough
(PhysicsWeb)
Researchers have created the first optical superlens from a thin layer of silver. The lens has a negative refractive index and can be used to image structures with a resolution that is about one sixth the wavelength of light -- thus overcoming the "diffraction limit".
[N Fang et al. 2005 Science 308 534]
(4.22.05)

Nanomagnets: Nanomagnets bend the rules
(Science Daily)
A class of nanostructured materials that are key components of computer memories and other important technologies undergo a previously unrecognized shift in the rate at which magnetization changes at low temperatures. This could prompt a reassessment of test methods used to predict technologically important properties of "ferromagnetic" materials.
(4.22.05)

Nanoscience: “Nanoshells” simultaneously detect and destroy cancerous cells
(ACS News)
Researchers have developed a new approach to fighting cancer, based on nanoscale particles that can both detect and destroy cancerous cells. Current molecular imaging approaches only detect the cancer but do not offer a method of treatment.
(4.20.05)

Biomaterials: Research reveals how materials direct cell response
(Bio.com)
While implanted biomaterials can be designed with different surface chemistries and roughness to influence inflammatory responses, the process is not well understood. Researchers have now discovered how cells "sense" differences in biomaterial surface chemistry. These differences in communication between the cell and the biomaterial result in changes in cell behavior.
(4.19.05)

Sensors: Laser sensor detects TNT vapor with unprecedented sensitivity
(Chemical & Engineering News)
A fluorescence sensor for explosives based on lasing of of semiconducting organic polymers is 30 times more sensitive than its predecessors. The sensor can easily detect TNT vapor at sub-parts-per-billion levels.
[Nature 2005, 434, 876]
(4.19.05)

© NASA
Cosmochemistry: Extrasolar planets could be made of diamond
(Nature News)
Researchers claim that some 'extrasolar' planets may have condensed from gas and dust that is rich in carbon. This could produce worlds made largely of hard carbon compounds such as silicon carbide. Their uppermost crust would consist of graphite. But deeper down, high pressure would transform graphite into diamond.
[Kuchner M. J. & Seager S. Arxivjournal, Preprint at http://xxx.arxiv.org/abs/astro-ph/0504214 (2005)]
(4.19.05)

Nickel: Unnatural look for Nickel
(PhysicsWeb)
Naturally occurring Ni has an FCC structure. Now, researchers have grown BCC Ni using molecular beam epitaxy. The BCC phase was also found to have positive magnetic anisotropy which the FCC phase has negative magnetic anisotropy.
[C S Tian et al., 2005 Phys. Rev. Lett. 94 137210]
(4.18.05)

Nanodiodes: Novel nanodiodes measure steady flow of energetic electrons
(Chemical & Engineering News)
A research team has constructed a nanoscale Schottky diode and used it to measure a continuous flow of hot electrons generated by catalytic surface reactions. They measured a continuous current of 40 µamp produced via oxidation of carbon monoxide on a platinum electrode for more than half an hour.
[Nano Lett. 2005 , 5 , 753]
(4.15.05)

Superconductivity: New wave of electrical wires inches closer to market (2005 MRS Spring Meeting News)
(Science)
Second-generation superconducting wires--made from yttrium, barium, copper, and oxygen (YBCO)--have been difficult to make in long lengths. Now, after a decade of slow and fitful progress, YBCO wires appear to be on the cusp of reaching the market.
(4.15.05)

Transistors: World's fastest transistor operates at blinding speed
(New Scientist)
The world's currently fastest transistor has been developed by a pair of US researchers.They developed pseudomorphic InP/InGaAs heterojunction bipolar transistors (PHBTs) using a compositionally graded collector (10% indium grading) and graded base (6% indium grading) to reduce the transit time of the device.
[W. Hafex and M. Feng, Appl. Phys. Lett. 86, 152101 (2005)]
(4.13.05)

Imaging: Soft tissue images get better
(OE Magazine)
Researchers have successfully demonstrated a novel "High-resolution Ultrasonic Transmission Tomography" (HUTT) system that offers 3-D images of soft tissue that are superior to those produced by existing commercial x-ray, ultrasound, or MRI units. HUTT offers nearly order-of-magnitude improvement in resolution of structures in soft tissue (i.e., 0.4 mm, compared to 2 mm for the best alternatives).
(4.13.05)

Nanoparticles: Sculpting traps for nanoparticles
(Nature Materials Update)
Nanoscale particles in solution diffuse along random, brownian trajectories. A new technique for trapping nanoscale particles has been developed that allows them to be held within a 'box' of more or less any shape, an ABEL (anti-brownian electrophoretic) trap, using electrical forces.
[Cohen A. E., Control of nanoparticles with arbitrary two-dimensional force fields. Phys. Rev. Lett. 94, 118102 (2005)]
(4.12.05)

Spectroscopic Ruler: A finer gauge of distance
(Nature Materials Update)
A 'ruler' for measuring distances of just 1–3 nm has been developed. Researchers have shown that the fluorescent light emission from an organic dye molecule can be switched off by red light, but that the close proximity of another dye switches the fluorescence back on. The effect depends very sensitively on the distance between them.
(4.12.05)

Biology: Recipe for flies' eyes: crystallize
(Science)
The striking hexagonal pattern in a fly's compound eye forms in the same way that a crystal grows, according to physicists who have modeled the chemical interactions driving the process. The layered pattern of atoms in a crystal emerges as additional atoms nestle into the dimples between those in the previous layer. In the same way, the pattern in the larval fruit fly's eye emerges as each new eyelet fits into a gap in the previous row of elements.
(4.12.05)

© L Kuipers (AMOLF)/PhysicsWeb
Photonic Crystals: Photonic crystals come under the microscope
(PhysicsWeb)
The photonic band structure of a photonic material has been measured for the first time. Researchers have developed a near-field optical microscope that can measure both the amplitude and phase of a light pulse as it travels through a photonic crystal.
[H Gersen et al. 2005 Phys. Rev. Lett. 94 123901]
(4.11.05)

Shock Physics: The Temperature in the Crunch
(Physical Review Focus)
Researchers have been able to measure the temperature of a fleeting shock wave by shooting neutrons through it and using neutron resonance spectroscopy. They created a shock wave in a sample of Mo, that contained a W-Mo alloy layer, by smacking it with an aluminum plate accelerated by an explosion to 3.6 kilometers per second, and the W nuclei were probed for neutron absorption.
[V. W. Yuan et al., Phys. Rev. Lett. 94, 125504
(issue of 1 April 2005)]
(4.11.05)

© Courtesy Zettl Research Group, Lawrence Berkeley National Laboratory and University of California at Berkeley
MEMS: The Smallest Electric Motor
(Physics News Update)
The smallest electric motor in the world has been developed, based on the shuttling of atoms between two metal droplets---one large and one small---residing on the back of a carbon nanotube.
(4.8.05)

© Alessandrini et al., Applied Physics Letters
Molecular Electronics: A Single-Protein Wet Biotransistor
(Physics News Update)
A single-protein wet biotransistor has been devised by physicists. A particular bacterial protein called azurin is used in a strategic position between two gold electrodes, which act as the source and drain of a transistor. A third electrode, acting as the gate, enables the centrally located azurin to allow the passage of an electrical current.
(4.8.05)

Nanotechnology: A standard system for naming nanomaterials
(Chemical & Engineering News)
Quantum dots, nanoshells, nanopeapods—all of these have been used for naming new nanomaterials. But without any systematic terminology or nomenclature, these descriptors, along with vague terms such as nanoparticle, are quickly becoming a big headache for regulators, patent lawyers, and journal editors. Scientists are now attempting to create a dictionary and standard terminology for the nanoscale.
(4.6.05)

NEMS: Zeptogram Mass Detection---Weighing Molecules
(Physics News Update)
Scientists have performed mass measurements with nearly zeptogram (zg) sensitivity, that is, with an uncertainty of only a few times 10^-21 grams. In experiments, the presence of xenon accretions of only about 30 atoms (7 zg, or about 4 kilodaltons, or the same as for a small protein) have been detected in real time.
(4.6.05)

Ceramics: Engineers Resurrect 900-year-old Ru Glaze Technology
(Science Blog)
The last Chinese potter who knew how to create a translucent, blue-green glaze known as "Ru glaze," died more than 900 years ago. Today, fewer than 100 Ru-glazed ceramics exist. None have been made during the past 900 years because no one has been able to reproduce the technology that created this delicate, opalescent finish. Researchers are now using SEM, molecular-level understanding of materials and a knowledge of high-tech ceramics to time travel through bits of existing Ru glaze for a peek back into 12th century China.
(4.6.05)

March

Patterning: Solvent evaporation leads to high-fidelity patterns
(Science Daily)
Resembling neatly stacked rows of driftwood abandoned by receding tides, particles left by a confined, evaporating droplet can create beautiful and complex patterns. The natural, pattern-forming process could find use in fields such as nanotechnology and optoelectronics.
(3.25.05)

Inkjet Printing: Inkjet prints human cells
(Technology Research News)
Inkjet printers have been used to make scaffolds for growing tissue and to spray cells in nutrient-rich liquids onto surfaces. Researchers have now devised a method that delivers human cells unharmed to chosen locations within polymer scaffolds.
(3.25.05)

© Appl. Phys. Lett., Univ. California/LBNL
Nanomachines: New look for nanomotors
(PhysicsWeb)
Researchers have built the first nanoelectromechanical device that exploits the effects of surface tension. The "relaxation oscillator" consists of two droplets of liquid metal on a substrate made of carbon nanotubes and can be controlled with a small applied electric field.
[B C Regan et al. 2005 Appl. Phys. Lett. 86 123119]
(3.23.05)

Nanoparticles: Control of Nanoparticles With Arbitrary Two-dimensional Force Fields
(Physical Review Focus)
A new trapping technique has been developed that effectively cancels out the Brownian motion of a nanoparticle by continually nudging it with just the right fluid flow. This has been used to trap and manipulate fluorescent plastic beads as small as 20 nanometers across.
[Adam E. Cohen, Phys. Rev. Lett. 94 , 118102
(issue of 25 March 2005)]
(3.23.05)

© Northwestern Univ.
Crystallization: Microscope zooms in on crystallization
(PhysicsWeb)
A new technique has been demonstrated that is capable of starting crystallization from scratch and then controlling and imaging the process as it proceeds in real time. An atomic force microscope coated with a polymer was used to grow crystals of the polymer on a mica substrate. New features of crystallization, previously too small to be detected, could now be observed for the first time.
[X Liu et al. 2005 Science 307 1763]
(3.21.05)

Granular Materials: Softening the Blow
(Physical Review Focus)
Granular materials can trap energy and release it slowly over time. The key is to arrange grains of different masses in specific patterns. A specially designed layer of spheres, arranged appropriately, can transform a single sharp blow into a sequence of much smaller impacts, a theoretical study predicts. Such a configuration might be used to construct a "granular protector" to shield delicate objects.
[Jongbae Hong, Phys. Rev. Lett. 94, 108001
(issue of 18 March 2005)]
(3.21.05)

Electric Current: Counting electrons one by one
(PhysicsWeb)
Researchers have counted individual electrons in an electrical current for the first time. They directly measured the oscillations associated with single electrons in a one-dimensional chain of superconducting "islands" connected by tunnel junctions. This could lead to the development of a new standard for electric current.
[J Bylander et al. 2005 Nature 434 361]
(3.21.05)

Memory Devices: Atoms never forget
(Nature News)
Researchers have shown that instead of using electrons, it is possible to create two states using an ordered or disordered arrangement of atoms. They used antimony telluride, which starts off in an 'amorphous' state. A small pulse of electricity provides enough heat to create an ordered, crystalline arrangement.
(3.21.05)

Photonic Crystals: Spiral Photonic Crystals
(Science - Editor's Choice)
Researchers have used direct laser writing to fabricate circular and square spiral architecture structures for three-dimensional photonic crystals using a polymeric photoresist. Complex defect structures could be engineered into the periodic crystal.
(3.18.05)

Nanotubes: Tiny porphyrin tubes could yield clean, inexpensive hydrogen
(Eurekalert)
Researchers have been able to create nanotubes composed entirely of porphyrins, which are light-absorbing molecules related to chlorophyll, the active part of photosynthetic proteins and light-harvesting nanostructures. Nanotubes with gold inside and platinum outside is the heart of a nanodevice that may split water into oxygen and hydrogen.
(3.18.05)

Biomaterials: Researchers make synthetic mother of pearl thin films
(Eurekalert)
Researchers have been able to grow thin films of nacre (mother of pearl) in the laboratory that are even stronger than the super-strong material that naturally lines the inside of abalone shells. They substituted in a material called chitosan, which is a naturally occurring compound in insect shells and the cell walls of fungi.
(News from the 229th ACS Annual Meeting)
(3.17.05)

Nanoparticles: Ceria nanoparticles catalyze reactions for cleaner-fuel future
(Eurekalert)
Experiments on ceria nanoparticles may lead to catalytic converters that are better at cleaning up auto exhaust, and/or to more-efficient ways of generating hydrogen. Researchers used bright beams of x-rays at the National Synchrotron Light Source to study how their composition, structure, and reactivity changed in response to doping with zirconium in one case, and impregnation with gold in another.
(News from the 229th ACS Annual Meeting)
(3.17.05)

Nanotubes: Carbon nanotubes modified using microwaves
(Eurekalert)
A novel method of changing the chemical characteristics of carbon nanotubes by heating them in a closed vessel microwave oven has been discovered. Since the reactions are fast, the nanotubes are not damaged or structurally modified.
(News from the 229th ACS Annual Meeting)
(3.17.05)

Nanotubes: Nylon-Nanotube Fibers
(Science - Editor's Choice)
Caprolactam was used as both solvent and monomer for incorporating single-walled nanotubes (SWNTs) into a nylon-6 matrix. The tensile strength and Young's modulus of nylon-6 improved by about a factor of 2 to 3 for SWNT loadings of 0.5 to 1.5 weight %.
[J. Am. Chem. Soc. 10.1021/ja446193 (2005)]
(3.11.05)

Biomaterials: Broken teeth
(Science - Editor's Choice)
Using interfacial fracture mechanics, Researchers showed that in a human tooth, the thin interface layer between enamel and dentin is not responsible for crack arrest for a crack propagating from the enamel. The dentin near the interface has collagen fibers that are preferentially oriented perpendicular to the interface and also has a lower mineral content relative to the bulk material, which prevents crack growth.
(3.11.05)

Gene Therapy: Polymer library could improve gene therapy for cancer
(NIBIB, NIH)
A team of researchers has devised a new technique that caused 40 percent of prostate tumors in mice to shrink in initial experiments. The research marks a significant advance in a method known as suicide gene therapy, which delivers a deadly payload directly to tumor cells, causing them to self-destruct. The team created a “library” of hundreds of polymers that might carry the genetic material to attack cancer cells, and then used automated screening techniques to