We showed that nanometre-sized ferromagnetic platelets suspended in a nematic liquid crystal can order ferromagnetically on quenching from the isotropic phase. Cooling in the absence of a magnetic field produces a polydomain sample exhibiting the two opposing states of magnetization, oriented parallel to the direction of nematic ordering. Cooling in the presence of a magnetic field yields a monodomain sample; magnetization can be switched by domain wall movement on reversal of the applied magnetic field. The ferromagnetic properties of this dipolar fluid are due to the interplay of the nematic elastic interaction (which depends critically on the shape of the particles) and the magnetic dipolar interaction. This ferromagnetic phase responds to very small magnetic fields and may find use in magneto-optic devices.
COBISS.SI-ID: 27304231
Optical waveguides of III-metal-polar and N-polar AlGaN are grown on sapphire substrates in order to test their use in integrated optics. The dispersion of the ordinary and extraordinary indices of refraction for films with aluminum mole fraction between 0.0 and 0.30 at four discrete wavelengths has been determined by the prism coupling method. The wavelength dependence of the refractive indices is described well by the first-order Sellmeier dispersion formula. The measurements show a small difference in the refractive indices between the two polarities, which is more pronounced at longer wavelengths.
COBISS.SI-ID: 2561124
Nd:YAP laser emitting at 1342 nm appears promising for nonablative skin rejuvenation treatment. Energy deposition profile in skin of four healthy volunteers was determined using the puklsed photothermal radiometry technique in comparison with more common Nd:YAG and KTP lasers. The results show that 50% of the Nd:YAP laser energy is deposited in the top 0.36 mm of skin, thereby enabling controlled heating of the upper dermis as required for nonablative skin rejuvenation. Moreover, the ratio between the dermal vs. epidermal heating is more favorable and shows a smaller inter- and intrapatient variance in comparison with either Nd:YAG or KTP laser.
COBISS.SI-ID: 26499367
G-wires - long, continuous G-quadruplexes - are a promising element for use in nanotechnology, particularly in molecular electronics. The pairing of G-quadruplex structures through complementary GC-termini was tested. We designed four analogous G-quadruplex-forming oligonucleotides with the same core sequence d(GGTG4TGG) and with different number and position of GC-ends. We used circular dichroism to determine the topology and relative orientation of G-quadruplexes, 1H NMR to identify Watson-Crick base pairing, and dynamic light scattering to examine the size of the G-quadruplex assemblies. The quadruplexes associated through GC-base pairs forming (G:C:G:C)-quartets and by stacking of unhindered terminal (G:G:G:G)-quartets. These two modes of association had different specificities: stacking occurred at both the 5'- and 3'- faces of the quadruplex, whereas GC-base pairing occurred only at the 5'-face of the quadruplex. These insights may be employed to design G-quadruplex-based nanowires or more complex architectures.
COBISS.SI-ID: 2606436
The article is an invited comment on the confirmation of he structure of a newly discovered twist- bend nematic phase.
COBISS.SI-ID: 2604132