Multifunctional soft hybrid bio-platforms based on nano-silver and natural compounds.

Novel nanohybrids consisting of nano-Ag, chitosan, lipids and phyto-compounds (chlorophyll a and curcumin) have been achieved through a simple bottom-up strategy, resulting in stable (ZP=-30.9mV) and spherical-shaped nano-entities with size <200nm (estimated by AFM analysis and DLS measurements). The formation of these biohybrids was monitored by absorption and emission spectroscopy, exploiting the spectral fingerprint of chlorophyll a. The bio-performances of these hybrid materials such as: high antioxidant activity (96.63%), strong biocidal properties against Escherichia coli ATCC 8738 (exhibiting an inhibition zone diameter of 32mm), hemocompatibility, in vitro cytotoxicity against HT-29 cancer cells and no toxicity to normal cells (in the biohybrid concentration range of 5.7-17%), make them promising candidates in bio-applications (antimicrobial and antioxidant coating, cancer treatment).

Control of the IR-spectral shift via modification of the surface relief between the liquid crystal matrixes doped with the lanthanide nanoparticles and the solid substrate.

The influence of the surface nanostructured relief on the near IR-spectral shift and on the structural properties of the nematic liquid crystal (NLC) materials doped with nanoparticles from lanthanide group has been considered. The relief mentioned above has been made on the interface between glass substrate with ITO-coatings and the LC mesophase. The specific feature of this relief is based on the applying of the contactless laser deposition technique and on the its modification by using surface electromagnetic waves (SEW) or carbon nanotubes (CNTs) treated with SEW. The modified relief permits to orient LC molecules without direct polymer orienting layers and can be used as conducting layer too. The features mentioned above lead to decrease drastically the resistivity and the bias voltage as well as that permits to increase the transparency and reveal the near IR-shift in the spectral characteristics of the lanthanide-doped LC mesophase.

Origin of Perpendicular Magnetic Anisotropy and Large Orbital Moment in Fe Atoms on MgO.

We report on the magnetic properties of individual Fe atoms deposited on MgO(100) thin films probed by x-ray magnetic circular dichroism and scanning tunneling spectroscopy. We show that the Fe atoms have strong perpendicular magnetic anisotropy with a zero-field splitting of 14.0±0.3 meV/atom. This is a factor of 10 larger than the interface anisotropy of epitaxial Fe layers on MgO and the largest value reported for Fe atoms adsorbed on surfaces. The interplay between the ligand field at the O adsorption sites and spin-orbit coupling is analyzed by density functional theory and multiplet calculations, providing a comprehensive model of the magnetic properties of Fe atoms in a low-symmetry bonding environment.

Lasing in DNA-CTMA doped with Rhodamine 610 in butanol.

The light emission properties of the complex formed from deoxyribonucleic acid (DNA)-cetyltrimethylammonium chloride (CTMA) surfactant doped with different concentrations of Rhodamine 610 (Rh610) dye and dissolved in butanol are investigated and discussed. The results are compared to those obtained when only the Rh610 dye is dissolved in butanol, at the same concentrations. The light emission is excited in the investigated samples by the nanosecond pulses of a frequency-doubled Nd:YAG laser, at a wavelength of 532 nm. We have demonstrated the lasing effect in the investigated complex and we have studied its efficiency and coherence properties. The lasing properties of the Rh610 dye are favourably influenced by the presence of the DNA-CTMA complex in the investigated compound. It leads to an increase in the lasing efficiency and in the slope efficiency. Also the temporal coherence of the emitted light is larger and the emission can be tuned to shorter wavelengths.

Pseudospin-resolved transport spectroscopy of the Kondo effect in a double quantum dot.

We report measurements of the Kondo effect in a double quantum dot, where the orbital states act as pseudospin states whose degeneracy contributes to Kondo screening. Standard transport spectroscopy as a function of the bias voltage on both dots shows a zero-bias peak in conductance, analogous to that observed for spin Kondo in single dots. Breaking the orbital degeneracy splits the Kondo resonance in the tunneling density of states above and below the Fermi energy of the leads, with the resonances having different pseudospin character. Using pseudospin-resolved spectroscopy, we demonstrate the pseudospin character by observing a Kondo peak at only one sign of the bias voltage. We show that even when the pseudospin states have very different tunnel rates to the leads, a Kondo temperature can be consistently defined for the double quantum dot system.

Duchenne muscular dystrophy in a 4-year-old girl due to heterozygous frame shift deletion of the dystrophin gene and skewed X-inactivation.

X-linked recessive diseases affect males, whereas female carriers are generally asymptomatic.We report on a 4-year-old girl who presented with a classical phenotype of Duchenne Muscular Dystrophy (DMD), a severe X-linked recessive type of muscular dystrophy affecting boys in early childhood.A thorough diagnostic work-up revealed that this resulted from a heterozygous out-of frame deletion in the DMD-gene in combination with an X-inactivation ratio of <10:90 in blood leukocytes and muscle.The case exemplifies that a skewed X-inactivation pattern has to be taken into account as mechanism causing clinical symptoms in female carriers of X-linked recessive disorders.

Coulomb blockade in an open quantum dot.

We report the observation of Coulomb blockade in a quantum dot contacted by two quantum point contacts each with a single fully transmitting mode, a system thought to be well described without invoking Coulomb interactions. Below 50 mK we observe a periodic oscillation in the conductance of the dot with gate voltage, corresponding to a residual quantization of charge. From the temperature and magnetic field dependence, we infer the oscillations are mesoscopic Coulomb blockade, a type of Coulomb blockade caused by electron interference in an otherwise open system.

Second-harmonic generation in poled polymers: pre-poling history paradigm.

Experimental studies of second harmonic generation (SHG) from electric-field poled PMMA - DR1 system show occurrence of a maximum in diagonal and off diagonal tensor components χ(2)(-2ω;ω,ω) at 15 mol % concentration and a rapid decrease above, with a stabilization. The origin of the observed concentration dependence is studied using the Monte Carlo (MC) modeling. We find that presence of maximum is conditioned by the pre-poling history of the sample, when entanglement of linear dipolar structures takes place. Length of the pre-poling interval is an important kinetic parameter which differentiates between various nonexponential kinetics of build-up of polar phase responsible for strong/weak SHG susceptibility.

Efficient second harmonic generation from thin films of V-shaped benzo[b]thiophene based molecules.

We have designed an original approach for efficient Second Harmonic Generation of tailored V-shape benzo[b]thiophene molecular systems enabling versatile and flexible one-step, dry and technologically friendly thin film processing. The designed moieties show chi((2)) values at least as high as the reference LiNbO(3) single crystal, without poling processing and matching the constrains of integrated optical configuration for nonlinear optical devices. This may open the way to a new class of organic materials exploitable for photonic applications.

Universal scaling in nonequilibrium transport through a single channel Kondo dot.

Scaling laws and universality play an important role in our understanding of critical phenomena and the Kondo effect. We present measurements of nonequilibrium transport through a single-channel Kondo quantum dot at low temperature and bias. We find that the low-energy Kondo conductance is consistent with universality between temperature and bias and is characterized by a quadratic scaling exponent, as expected for the spin-1/2 Kondo effect. We show that the nonequilibrium Kondo transport measurements are well described by a universal scaling function with two scaling parameters.

Observation of the two-channel Kondo effect.

Some of the most intriguing problems in solid-state physics arise when the motion of one electron dramatically affects the motion of surrounding electrons. Traditionally, such highly correlated electron systems have been studied mainly in materials with complex transition metal chemistry. Over the past decade, researchers have learned to confine one or a few electrons within a nanometre-scale semiconductor 'artificial atom', and to understand and control this simple system in detail(3). Here we combine artificial atoms to create a highly correlated electron system within a nano-engineered semiconductor structure. We tune the system in situ through a quantum phase transition between two distinct states, each a version of the Kondo state, in which a bound electron interacts with surrounding mobile electrons. The boundary between these competing Kondo states is a quantum critical point-namely, the exotic and previously elusive two-channel Kondo state, in which electrons in two reservoirs are entangled through their interaction with a single localized spin.

[The effective method for detection of IgG-antibodies of AB0 system and its rapid micromodification ]. / Effektivnyi metod vyiavleniia IgG-antitel sistemy AB0 i ego uskorennaia mikromodofikatsiia.

Presents a method for measuring AB0 antibodies (IgG) in the serum and/or colostrum with 2-mercaptoethanol pretreatment to reduce disulfide bonds in the IgM molecule. Offers a highly sensitive, rapid, economic, and effective variant of the test in polystyrene plates for immunological tests, which can be used in screening studies.

[Visually evoked P300 waves]. / Visuell ausgelöste P300-Wellen.

The event-related potentials after a competitive visual stimulation are presented. The stimulation with target stimuli results in two pronounced positive potentials in the grand-average, the P2 and the P3 component of the ERP, and a long-lasting positivity following the P3 wave. Similar but smaller potential components are elicited by non-target stimuli. Some examples of individual ERP demonstrate the high degree of inter-individual variability, as in the positive components as in the restoration of the poststimulus baseline. Some aspects of a possibly fundamental difference between visually and acoustically elicited P300 waves are demonstrated.

[Effects of dequalinium chloride and sanguinarine on the ultrastructure of early supragingival plaque]. / Die Wirkung von Dequaliniumchlorid und Sanguinarin auf die Ultrastruktur der frühen supragingivalen Plaque.

The influence of antimicrobial mouthrinses containing dequalinium chloride or sanguinarine on early plaque formation was assessed in vivo in a clinical-experimental study. Rinses with water served as controls. After 24 and 72 hours, plastic films, which were applied to the buccal surfaces of six upper front teeth at the start of experiment, were removed and processed for transmission electron microscopic study. Dequalinium chloride or sanguinarine applied on plaque resulted in an increased and higher structured surface coating. Degenerated microorganisms were observed and the variety of bacteria seemed to be reduced. Both mouthrinses effected the early supragingival plaque formation. The effect of sanguinarine was more intensive than that of dequalinium chloride.