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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 zero in on the best candidates quickly.
[DG Anderson et al., A polymer library approach to suicide gene therapy for cancer, Proc Natl Acad Sci USA 101: 16028-16033, 2004]
(3.9.05)

Quantum Dots: 'Birth' of semiconductor nanostructures imaged
(PhysOrg)
Researchers combined molecular-beam epitaxy with scanning tunneling microscopy to witness the creation of quantum dots, or atomic islands, of indium gallium arsenide (InGaAs) atoms atop a gallium arsenide (GaAs) surface.
(3.9.05)

© NASA JPL
Electroactive Polymers: Robot arms lose quickly to teenage girl
(Scientific American)
At a conference held in San Diego, three robotic arms tested their might against a human opponent in arm wrestling matches, which the flesh-and-blood contestant won handily.
(3.9.05)

© Univ. of Illinois
Sonoluminescence: Bubbles feel the heat
(PhysicsWeb)
A region of plasma in a single-bubble sonoluminescence experiment in collapsing bubbles has been observed for the first time. The temperature inside the bubble was found to reach up to 20,000 K.
[D Flannigan and K Suslick 2005 Nature 434 52]
(3.7.05)

X-Rays: X-rays from lightning
(Physics News Update)
Experiments have shown that lightning emits large bursts of x-rays with energies up to about 250 keV. The bursts of x-rays appear to be produced at the precise moment that the lightning steps forward along its jagged path.
(3.7.05)

Nanotubes: New life for nanotubes
(Nature Materials Update)
Resesarchers have discovered a method for restarting the growth of open-ended carbon nanotubes in a way that preserves the atomic-scale structure of the original tubes. The 'fresh growth' of the tube, catalysed by a metal nanoparticle sitting at the tube's open tip, preserves both the diameter and the helical pitch of the rows of hexagonal carbon-atom rings of these features of the initial tube.
(3.4.05)

© Purdue Univ.
Optical Microscopy: Devising nano-vision for an optical microscope
(OE Magazine)
A hybrid version of the optical microscope might be able to image and measure features smaller than 10 nm. In a preliminary test scientists used violet light with a wavelength of 436 nm to image features as small as 40 nm, which is about five times smaller than possible with a conventional optical microscope.
(3.3.05)

Mass Spectroscopy: No-prep mass spec
(Chemical & Engineering News)
A new method for mass spectroscopy called direct analysis in real time or DART has been developed. DART can analyze liquids, gases, and surfaces without sample preparation at atmospheric pressure, so no vacuum is required. It works by applying an electrical potential to a gas to form a plasma of excited-state atoms and molecules that then interact with the sample and the atmosphere.
(3.2.05)

Covalent Bonds: New look for chemical bonds
(PhysicsWeb)
A new type of chemical bond has been discovered in molecules that contain two uranium atoms. A total of ten electrons, or the equivalent of five covalent bonds, are involved in the bonds. Previously the record for the largest number of covalent bonds in a molecule was four.
[L Gagliardi and B Roos 2005 Nature 433 848]
(3.2.05)

February

Nanoparticles: Bimetallic nanoparticles break down pollutant 100 times faster than bulk catalysts
(Rice University)
Nanoparticles of gold and palladium have been found to be the most effective catalysts yet identified for remediation of one of the most pervasive and troublesome groundwater pollutants, trichloroethene or TCE. The gold-palladium nano-catalysts break TCE down about 100 times faster than bulk palladium catalysts. The nanoparticles maximize the number of palladium atoms that come in contact with TCE molecules.
(2.24.05)

Nanoparticles: High-intensity ultrasound creates hollow nanospheres and nanocrystals
(University of Illinois)
High-intensity ultrasound was used to generate nanoparticles of molybdenum disulfide or molybdenum oxide, which bind to the surface of tiny silica spheres that are much smaller than red blood cells. After heating the spheres to produce uniform coatings, hydrofluoric acid was used to etch away the silica, leaving hollow shells of the desired material.
(2.24.05)

Nanomachines: Motoring Oil Drops
(Physical Review Focus)
Researchers have described the cyclical motion of oil droplets powered by the repulsion between oily and watery molecules, a principle that is similar to biological motors and one which they believe could power nanomachines of the future. They have also found a way to make the "motor" more effective by allowing it to trace the same path over and over.
[Y. Sumino et al., Phys. Rev. Lett. 94, 068301 (issue of 18 February 2005)]
(2.24.05)

© Physics Web
Exciplex: Novel molecule makes its debut
(PhysicsWeb)
A novel type of molecule known as an exciplex - short for excited complex - has been observed for the first time. Exciplexes are molecules that can only exist if one of the atoms in the molecule is in an excited state. Scientists have seen evidence for an exciplex that contains one caesium atom and seven helium atoms, as well as a simpler version that contains just two helium atoms.
[D Nettels et al. 2005 Phys. Rev. Lett. 94 063001]
(2.22.05)

Muon Radiography: Muons in search of hidden pyramid chambers
(PhysOrg)
Muons are created by cosmic rays and scientists are beginning to use them as probes of dense objects, including a massive pyramid in Mexico and volcanoes in Japan. American researchers also have proposed using the energetic particles to detect smuggled nuclear materials in vehicles and cargo containers.
(2.22.05)

© Boston Univ.
Nanomachines: Fastest oscillating nanomachine developed
(Physics News Update)
A new study provides evidence for quantized displacement in nanomechanical oscillators. An experiment was performed in which tiny silicon paddles, sprouting from a central stick of silicon like the vanes from a heat sink, seem to oscillate together in a peculiar manner: the paddles can travel out to certain displacements but not to others. The device oscillates at 1.49 gigahertz.
[Phys.Rev.Lett. 94, 030402 (2005)]
(2.18.05)

Proteins: Coral Harvest Yields Fluorescent Light Switch
(The Scientist)
A fluorescent protein has been developed that can be switched on and off more than 100 times. The protein was engineered from a coral and it was found that strong irradiation at 488 nm converts it to a nonfluorescent state absorbing at 390 nm. This darkened protein can be switched back to its original emission state by irradiation for several minutes at 405 nm.
(2.18.05)

Quantum Dots: Quantum-Dot photon detectors
(Physics News Update)
A device has been developed based on a quantum dot that can efficiently detect single photons. The quantum dot is encased inside a resonant tunneling diode.
(2.18.05)

© Intel
Lasers: Silicon laser runs non-stop
(Nature News)
A silicon laser than produces a continuous beam of laser light has been unveiled. The silicon laser ran continuously at room temperature for as long as the power was on.
(2.17.05)

© Purdue Univ.
Nanostructured Materials: Concept of using nano-materials for drug discovery demonstrated
(Purdue University)
Researchers have built and demonstrated a prototype for a new class of miniature devices to study synthetic cell membranes to speed the discovery of new drugs. They created a chip about one centimeter square that holds thousands of tiny vessels sitting on top of a nanoporous material that contains numerous pores. This makes it possible to carry out reactions inside the vessels.
(2.17.05)

Mechanobiology: Mechanical tension helps shape lung development
(AAAS Annual Meeting)
Researchers have demonstrated that the process of budding and branching in the developing lung is driven by mechanical forces generated within individual cells. They have also identified a possible biochemical target for intervention. These insights could lead to new ways to prevent, minimize or even correct diseases and anomalies of the lungs, which are common in premature newborns.
(2.17.05)

Organic LEDs: Longer lives for organic LEDs
(PhysicsWeb)
It has been demonstrated that the performance of organic light-emitting diodes can be improved by doping them with carbon-60. The carbon-60 molecules can also extend the lifetime of the devices by a factor of two.
[J Y Lee and J H Kwon 2005 Appl. Phys. Lett. 86 063514]
(2.16.05)

X-Rays: X-rays become laser-like
(Max-Planck-Gesellschaft)
Researchers have demonstrated the first source of laser-like X-rays at a wavelength of 1 nanometer using a compact laboratory apparatus. The team focused a sequence of intense ultrashort flashes of red light at a gas of He atoms to convert 700-nm laser light into a 1-nm wave of X-ray light emitted by the excited atoms.
[Nature 433, 596 (2005)]
(2.15.05)

Surfaces: Watching atoms move
(Physical Review Focus)
An ultrastable scanning-tunneling microscope has been developed that can remain fixed on the same set of surface atoms, even with a rising temperature. This was used to observe a specific set of atoms continuously during a surface phase transition and the researchers were able to learn how the transition occurs, atom-by-atom, in a perfectly clean system.
[Phys. Rev. Lett. 94 , 046101 (2005)]
(2.15.05)

Inorganic Synthetic Chemistry: Iron-sulfur core assembled
(Chemical & Engineering News)
Hydrogenases are enzymes that enable bacteria to evolve or take up hydrogen and use it as a metabolic oxidizing or reducing agent. An inorganic complex very similar to the catalytic iron-sulfur core of bacterial hydrogenase has not been developed. Such synthetic systems could be developed for reversible hydrogen fuel cells that would not require expensive platinum catalysts.
[Nature, 433, 610 (2005)]
(2.14.05)

© PhysicsWeb
Nanotechnology: Nanobelts sense nerve gases
(PhysicsWeb)
Tin oxide "nanobelts" have been combined with low-power microheaters to make sensors that can detect nerve agents. The devices are ultrastable, highly sensitive and free from the "poisoning effect" that has previously limited the widespread use of metal oxides as sensors.
[C Yu et al., Appl. Phys. Lett. 86 (2005) 063101]
(2.10.05)

Carbon: Liquid carbon created and studied
(Physics News Update)
Liquid carbon was created and studied by blasting a solid sheet of C with an intense laser beam. Before the liquid could vaporize, its structure was quickly probed by an x-ray beam.
(2.10.05)

Feature
Nanotribology: Friction at the nano-scale
(PhysicsWeb)
Nanomachines will depend on knowledge of friction, heat transfer and energy dissipation at the atomic level for their operation and survival. In the scramble to revolutionize the world with nanotechnology friction must not be ignored.
(2.10.05)

Ink-Jets: Low pressure improves ink jets
(Nature News)
A spray in a vacuum does not make a splash, researchers have found. It was shown that lowering the air pressure in which a spray is projected can reduce and even eliminate splashing. This could lead to cleaner ink-jet printing and smoother spraying of surfaces.
(2.9.05)

Welding: New method for predicting fatigue life in welded structures developed
(ASM International )
A new method for predicting fatigue life in welded structures has been developed. The new "Verity mesh-insensitive structural stress method", has been shown to be very accurate. The fatigue lives of welded structures now can be reliably predicted regardless of the complexity of welded components and modeling details.
(2.9.05)

Nanoparticles: Self-assembled nano-sized probes used to see tumors through flesh and skin
(Eurekalert)
Nano-sized particles embedded with bright, light-emitting molecules have enabled researchers to visualize a tumor more than one centimeter below the skin surface using only infrared light. When exposed to near-infrared light, the molecules embedded within the polymersome respond with a detectable infrared signal. The emissive polymersomes represent the first optical imaging platform based on soft matter.
(2.8.05)

Lasers: Optics enters the single-cycle regime
(PhysicsWeb)
The shortest-ever laser pulse at optical frequencies has been produced. The pulse lasted for just 1.6 femtoseconds, which corresponds to just 0.8 of an optical cycle for pulses with a central wavelength of 650 nanometres.
[M Y Shverdin et al. 2005 Phys. Rev. Lett. 94 033904]
(2.7.05)

© NanoTechWeb
Scanning Probe Microscopy: Butterfly images take flight
(NanoTechWeb)
Atomic force acoustic microscopy has been used to view the structure of a butterfly wing and to determine its mechanical and electromechanical properties.
(2.7.05)

Microfluidics: Microfluidic device optimizes complex organic transformations
(Chemical & Engineering News)
A continuous-flow silicon microfluidic microreactor has been developed that can be used to optimize the yield and selectivity of a variety of reactions using milligram amounts of starting materials. For example, it can be used to systematically study and determine the optimal reaction conditions for glycosylation reactions.
[Chem. Commun., 2005, 578]
(2.7.05)

© NanoTechWeb
Carbon Nanotubes: Double-walled carbon nanotubes could beat single-walled
(NanoTechWeb)
Double-walled nanotubes could have physical properties superior to those of single- or multi-walled nanotubes. A new high-yield technique has now been developed for making double-walled carbon nanotubes.
(2.4.05)

© Georgia Tech
Nanoscience: Evidence of Charging of Nanocatalysts Found
(Georgia Inst. of Technology)
Studying nano-sized clusters of gold on a magnesium oxide surface, scientists have found direct evidence for electrical charging of a nano-sized catalyst. This is an important factor in increasing the rate of chemical reactions.
(2.4.05)

Tissue Engineering: Bioengineered tissue scaffold promotes wound healing
(NIBIB, NIH)
A material called small intestinal submucosa (SIS) developed from the small intestines of pigs is increasingly used by surgeons to restore damaged tissues and support the body’s own healing process. Physicians rely on the material for everything from reconstructing ligaments to treating incontinence. Today, SIS is most commonly used to help the body close hard-to-heal wounds.
(2.2.05)

© PhysicsWeb
Liquids: Making a splash
(PhysicsWeb)
For water droplets splashing off a surface, new experiments show that the viscosity of the liquid plays a critical role, but so does the pressure and molecular weight of the gas that the drop falls through. These results could be relevant in applications such ink-jet printing and the combustion of liquid fuels.
[L Xu et al. 2005 arXiv.org/abs/physics/0501149]
(2.1.05)

Catalysts: High-throughput screening reveals promising low-cost Co-Ba catalyst
(Chemical & Engineering News)
Using a high-throughput reactor, researchers have discovered a catalyst formulation that includes no precious metals yet rivals the performance of catalysts containing platinum and other expensive materials. The catalyst uses cobalt as an oxidizing metal and contains no noble metals, and is just as effective at treating NOx as platinum-based catalysts.
[Catal. Commun., 6, 167 (2005)]
(2.1.05)

January

Microscopy: A Microscope from Flatland
(Physical Review Focus)
Researchers have come up with a way to coax plasmons into magnifying images. They place a microscopic sample onto a thin, metal-coated glass surface and deposit a drop of glycerin on top of it. Next, they shine laser light through the glass, which creates surface plasmons in the metal coating. The plasmons "sense" the sample by scattering off of it. They can sense finer details than ordinary light because their wavelength is only 70 nanometers, seven times shorter than that of the laser.
(1.28.05)

Data Storage: A Phase Change in High-Density Data Storage
(Physics News Update)
Researchers have created individual bits in the form of tiny amorphous regions inside a thin indium-selenium layer. That layer, along with another layer beneath (gallium-selenium) and a silicon substrate, form the principal parts of a pn-junction diode. Short, high-power bursts from an electron beam are used to write a "1" by melting a tiny portion of the InSe layer, turning it into a glassy blob. Alternatively the blob can be erased by the use of a longer, low-power beam pulse, which recrystallizes the material.
(1.27.05)

Organic-Metallic Interface: Organic Molecules on the Rebound
(Physics News Update)
The precise structure of a large organic molecule after its interaction with a metal surface has been determined using synchrotron radiation. The structure information was used to understand the chemical bond between the molecule and the surface. The organic-metallic interface is very important in science, especially in the fields of catalysis, bio-sensing, and molecular electronics.
(1.27.05)

Aerogels: Semiconducting chalcogenide nanoparticles transformed into aerogels
(NanoTechWeb)
Metal chalcogenide nanoparticles have been assembled into an aerogel. The semiconducting materials had the same optical properties as their nanoparticle constituents.This opens up a new class of aerogels: chalcogenide aerogels, whereas, previously, aerogels were limited to metal oxides and carbon.
(1.24.05)

Bioengineering: Micro musclebot moves by heart cells' beats
(Science News Online)
Researchers have created living micromachines using cardiac muscles. Each tiny device consists of an arch of gold coated along its inner surface with a sheath of cardiac muscle grown from rat cells. With each of the muscle bundles' automatic cycles of contraction and relaxation, the device takes a step.
(1.24.05)

Micromachining: First life-sized fully microengineered artificial cochlea built
(PhysicsWeb)
The first life-sized fully micromachined artificial cochlea has been built. The device works in the same way as the cochlea in a real ear. "Deep reactive ion etching" was used to fabricate the device.
[R.D. White and K. Grosh, Proc. Natl. Acad. Sci. USA , 10.1073/pnas.0407446102]
(1.24.05)

Nanowires: Proteins glue semiconductor nanowires together
(NanoTechWeb)
Biological molecules have been used to control the assembly of nanowire structures. Researchers used two types of biological connectors to assemble cadmium tellurium (CdTe) nanowires - a complimentary antigen-antibody pair (bovine serum albumin (BSA) and the anti-BSA antibody IgG) and biotin-streptavidin.
(1.24.05)

Strain: Measuring disordered strain
(Science - Editor's Choice)
A new technique has been developed for measuring strain distributions in amorphous materials. A bulk metallic glass based on magnesium, copper, and yttrium was exposed to high-energy x-rays, and then compressed it in situ. Two methods were used to analyze the nearly circular symmetric diffusion patterns, one based on Q space and the other on direct space, and both depend on the shift in the position of the first peak (relative to the uncompressed reading) for determining the strain in the sample.
[Nature Mater. 4 , 33 (2005)]
(1.21.05)

Atomic Force Microscopy: Looking at electrons without touching
(PhysicsWeb)
A new way to investigate single-electron effects in quantum structures without the need to attach leads to the system being studied has been demonstrated. The method, dubbed electrostatic force spectroscopy, relies on an atomic force microscope and has a spatial resolution of 50 nm.
[R Stomp et al. 2005 arXiv/cond-mat/0501272]
(1.20.05)

Fullerenes: Filling A Fullerene
(Chemical & Engineering News)
Using organic synthesis as a scalpel and stitches, "molecular surgery" has been performed on a buckyball. Researchers created an opening in the molecule, inserted hydrogen into the cavity, and then, in just four steps, closed up the C₆₀ framework to construct the endohedral fullerene H₂@C₆₀.
[Science, 307, 238 (2005)]
(1.20.05)

Low-Temperature Physics: Electron clouds can freeze into an "Orbital Glass"
(Physics News Update)
Scientists have found that orbital processes can slow down dramatically—to as long as 0.1 seconds, a slowing by 14 orders of magnitude—for electrons in low-temperature FeCr₂S₄, a spinel with a relatively simple crystalline structure.
(1.20.05)

Ultrathin Films: Floating films on liquid mercury
(Brookhaven National Laboratory)
Researchers have grown ultrathin films of organic chain molecules on the surface of liquid mercury and have discovered that the molecules form ordered structures.
(1.18.05)

Superatoms: Clusters of Aluminum Atoms Found to Have Properties of Other Elements
(AZOM)
It has been discovered that clusters of aluminum atoms have chemical properties similar to single atoms of metallic and nonmetallic elements when they react with iodine. This could open the door to using 'superatom chemistry' based on a new periodic table of cluster elements to create unique compounds with distinctive properties never seen before.
(1.18.05)

Photovoltaics: Nanocrystal-polymer composites detect infrared wavelengths
(NanoTechWeb)
Canadian researchers claim have made the world's first solution-processed photovoltaic devices that respond to infrared. They combined infrared-sensitive nanocrystals of lead sulphide (PbS) with a conjugated polymer. They used around 90% nanocrystals by weight, dissolving the two components in chloroform before spin-coating the material onto a substrate to create a film.
(1.13.05)

Atomic Force Microscopy: Nanoneedle gets into cells
(NanoTechWeb)
Nanoneedles attached to an atomic force microscope (AFM) have been used to penetrate the nucleus of living cells. The needles were etched from pyramidal silicon AFM tips using focused ion beam etching. The scientists say this is the first time that solid material was inserted into the nucleus of such a small living cell with highly accurate positioning.
(1.13.05)

Atomic Oxygen: Oxygen gives new life to art
(Chemical & Engineering News)
Using an atomic oxygen treatment originally developed to mimic the upper reaches of the atmosphere, NASA scientists have cleaned up damaged artwork that was once considered unsalvageable. They have also used the technique to restore an Andy Warhol painting.
(1.12.05)

Atomic Force Microscopy: Making microscopes go faster
(PhysicsWeb)
An atomic force microscope has been demonstrated that can take images of periodic processes with a time resolution of microseconds. This is an order of magnitude faster than is possible with conventional the "rapid-scan" technique. The new "step-scan" technique involves a series of individual force-sensing measurements that are combined to construct images.
[M Anwar and I Rousso, Appl. Phys. Lett 86 (2005) 014101]
(1.10.05)

Amorphous Alloys: Highly plastic metallic glasses
(Nature News)
Researchers have reported a monolithic bulk metallic glass with a plasticity of up to 20% in contrast to the usual plasticity of about 2%. The alloy made of platinum, copper, nickel and phosphorus builds up a large number of shear bands under compression, rather than the single shear band formed in most metallic glasses.
[Schroers A. & Johnson W. L. Ductile bulk metallic glass. Phys. Rev. Lett. 93, 255506 (2004)]
(1.10.05)

Liquid Crystals: Custom-made molecules assemble into pentagonal and other unusual patterns
(Chemical & Engineering News)
Researchers have shown that custom-made molecules can assemble into liquid-crystal networks based on pentagonal honeycombs and other unusual patterns. The study presents new methods for controlling supramolecular architectures and could eventually lead to new types of materials used in liquid-crystal displays and related technologies.
[Science, 307, 96 (2005)]
(1.10.05)

Drug Delivery: Smart bombs to blast tumors
(New Scientist)
An ingenious method of delivering drugs to tumors has been developed. The drug is enclosed in polymer capsules peppered with gold nanoparticles and attached to tumour-seeking antibodies. When injected into the bloodstream, the capsules concentrate inside tumours. When enough capsules have gathered there, a pulse from a near-infrared laser melts the gold, which strongly absorbs near-infrared wavelengths. This will rupture the plastic capsules and release their contents.
(1.7.05)

Biochemistry: Quick drying foam
(Science - Editor's Choice)
Sandcastle worms build shelters by gathering sand grains and gluing them together into a sturdy tube, using a rather sophisticated construction material. Researchers have now analyzed the structure and composition of this glue.
[J. Exp. Biol. 207, 4727 (2004)]
(1.7.05)

© American Chemical Society
Nanoparticles: Bright and Stable Core-Shell Fluorescent Silica Nanoparticles
(Science - Editor's Choice)
Scientists have created a hybrid structure with an organic fluorophore covalently attached to a silica precursor, forming an organic core surrounded by a thin silica shell. This is then encapsulated using sol-gel chemistry to make particles 20 to 30 nm in diameter. Adding the outer shell of silica increased the fluorescence brightness by a factor of 30.
[Nano Lett. 10.1021/nl0482478 (2004)]
(1.7.05)

Lasers: All silicon laser developed
(PhysicsWeb)
Scientists have made a compact all-silicon Raman laser on a single silicon chip. This is the first all-silicon laser. This could lead to the development of silicon chips that can be used in both electronic and photonic applications.
[H. Rong et al. Nature AOP, published online 5 January 2005; doi:10.1038/nature03273]
(1.6.05)

Nanowires: Nanowires form atomic switch
(NanoTechWeb)
A nanoscale mechanical switch that could ultimately replace semiconductor switches in electronic devices has been demonstrated. The quantized conductance atomic switches were operated by controlling the formation of an atomic bridge between two nanowires, one made from platinum and the other from silver sulphide, spaced about 1 nm apart. Applying a positive bias voltage to the silver sulphide caused a silver nano-protrusion to form, creating a bridge between the two wires.
(1.6.05)

2004 MRS Fall Meeting News: Materials Potpourri
(Chemical & Engineering News)
Spotlight on the 2004 MRS Fall Meeting. Light sensors in a brittlestar; the first nanotube-based commercial hydrogen sensor; dumplings and donuts - the shapes of block copolymers; regenerative medicine meets nanotechnology; confocal X-ray fluorescence (XRF) spectroscopy for art conservation; fighting tumors with gold nanocomposites.
(1.4.05)

Sensors: Tiniest magnetic sensor developed
(EarthTimes.org)
A low-power magnetic flux sensor has been developed that can detect magnetic field changes as small as 50 picoteslas – magnetic field million times weaker than that of Earth. The device runs on a battery is not bigger than a grain of rice. The new sensor is based on chip-scale atomic clock.
(1.3.05)

© Univ. California, Santa Barbara
Nanoscience: Scientists Build Nanoscale ‘Jigsaw' Puzzles Made of RNA
(University of California, Santa Barbara)
Researchers are using assembly and folding principles of natural RNA, or ribonucleic acid, to build beautiful and potentially useful artificial structures at the nano-scale. This concept, called RNA tectonics, has led to the synthesis of RNA grids with finite size and various patterns. Using atomic force microscopy, they have been able to visualize some of their assemblies made of square-shaped RNA units that form the patterns and nano-grids.
(1.3.05)

Concrete: Concrete Nation - Bright future for ancient materials
(Science News Online)
Scientists and architects have been pushing the limits of concrete to give it new features and creative functions,such as, for example, ultrahigh-performance concrete that bends like metal and another type of concrete that forms translucent blocks.
(1.3.05)