C<Subscript>60</Subscript> fullerene decoration of carbon nanotubes

A new fully carbon nanocomposite material is synthesized by the immersion of carbon nanotubes in a fullerene solution in carbon disulfide. The presence of a dense layer of fullerene molecules on the outer nanotube surface is demonstrated by TEM and XPS. Fullerenes are redistributed on the nanotube surface during a long-term action of an electron beam, which points to the existence of a molecular bond between a nanotube and fullerenes. Theoretical calculations show that the formation of a fullerene shell begins with the attachment of one C₆₀ molecule to a defect on the nanotube surface.     

Observation of ultrasound velocity gradient in fullerene ceramics by acoustic microscopy

A scanning acoustic microscope is used to study the distribution of elastic properties in small samples (O 3 x 2 mm3) of new hard phases of C60. The specimens under investigation were synthesized from pure C60 powder under pressure P = 8 GPa in the temperature range 500-1650 K. The time-of-flight mode was used for bulk sound wave velocity determination in a direction parallel to the cylinder's axis. Longitudinal sound wave velocities greater than 10,000 m/s were found for all specimens treated at temperatures higher than 1000 K. Using the B-scan mode allowed us to observe the velocity gradient in the sample's periphery. The heterogeneous internal structure of the specimen is visualized in the images formed in C- and B-scan modes.     

Bilayer microfluidic chip for diffusion-controlled activation of yeast species

A bilayer microfluidic chip is used, in which multiple laminar streams are generated to define local microenvironments. The bilayer architecture of the microchip separates cell handling and positioning from cell activation by soluble chemicals. Cell activation is diffusion controlled through a porous membrane. By employing time-lapse fluorescence microscopy, gene expression of the enhanced green fluorescent protein (eGFP) in Saccharomyces cerevisiae is studied under various conditions. We demonstrate that the yeast cells remain viable in the microchip for at least 17h, and that gene expression can be initiated by the supply of the inducer galactose at a spatial precision of a few micrometers.     

New developments in catalysis

Environmental, safety and health concerns are major driving forces for the development of new coating systems, which in turn require catalysts with a different performance profile. One critical area for the development of new catalysts is the replacement of organotin compounds in polyurethanes with environmentally friendly catalysts, such as bismuth, aluminum and zirconium chelates. For applications in epoxies new catalysts for the epoxy-carboxyl reaction are also being developed. To gain the needed improved performance multiple cure mechanisms are being employed in coatings requiring dual action catalysts.     

Stimulation of the stress response by low-frequency electromagneticfields: possibility of direct interaction with DNA

This paper reviews research in our laboratories, which shows that 60-Hz electromagnetic fields stimulate the stress response at field strengths much lower than 0.1 mT (1 Gauss). While research on weak electromagnetic fields has been directed largely toward possible harmful effects, the stimulated expression of stress genes (i.e., synthesis of stress proteins) has many potential therapeutic applications in medicine. To gain insight into the molecular mechanism, we have studied the interactions of fields with well-characterized enzymes, and our findings suggest a coupling of the fields to biological charge transfer reactions. Since, synthesis of stress proteins requires activation of DNA, electromagnetic fields may achieve this by interacting directly with electron currents that flow through the stacked bases within the DNA. Such processes could explain the unusually low thresholds we observe and provide a basis for understanding biological effects of high-frequency electromagnetic fields     

Imposed layer-by-layer growth by pulsed laser interval deposition

Pulsed Laser Deposition (PLD) has become a significant technique to study the thin film growth of novel materials. Here, one has benefited from the main advantages of PLD, the relative easy stoichiometric transfer of material from target to substrate and the almost free choice of (relatively high) background pressures. However, the applicability of PLD is still hampered, because real time in situ growth monitoring was almost not available. For example, Reflection High-Energy Electron Diffraction (RHEED) was limited to low background pressures only until recently. High pressure RHEED, which makes it possible to in situ monitor during deposition of oxides at the higher pressures, opened new possibilities [1]. Besides observed intensity oscillations due to layer by layer growth, enabling accurate growth rate control, it became clear that intensity relaxation observed due to the typical pulsed way of deposition leads to a wealth of information about growth parameters [2]. Here, PLD in combination with high pressure RHEED is used to study the influence of the different parameters on the growth mode, resulting in a new approach to impose layer by layer growth by interval deposition.     

Dodecaindane (tBu3Si)8In12—A Compound with an In12 Deltapolyhedron Framework

A unique feature among polyhedron frameworks of boron group elements is exhibited by the In₁₂ framework of the black-violet dodecaindane R^*₈In₁₂ (R*=SitBu₃), which can be obtained by the thermolysis of R^*₂In−InR^*₂. The molecular structure of R^*₈In₁₂ (tBu groups omitted in picture shown) can be described as a combination of two R^*₄In₆ octahedral building blocks and can thus be classified as a conjuncto dodecaindane.     

Precise half-life measurement of the 26Si ground state

The β-decay half-life of ²⁶Si was measured with a relative precision of 1.4·10^?3. The measurement yields a value of 2.2283(27) s which is in good agreement with previous measurements but has a precision that is better by a factor of 4. In the same experiment, we have also measured the non-analogue branching ratios and could determine the super-allowed one with a precision of 3%. The experiment was done at the Accelerator Laboratory of the University of Jyväskylä where we used the IGISOL technique with the JYFLTRAP facility to separate pure samples of ²⁶Si.