ABSTRACT Copper is an essential micronutrient used as a metal cofactor by variety of enzymes, including cytochrome c oxidase (Cox). In all organisms from bacteria to humans, cellular availability and insertion copper into target proteins are tightly controlled due its toxicity. The major subunit Cox contains atom that required for catalytic activity. Previously, we identified CcoA (a member facilitator superfamily transporters) component cbb 3 -type production in the Gram-negative,...

The purely hexagonal phase of ultrasmall (~10 nm) NaYF(4) nanocrystals (NCs), containing different Eu concentrations, has been obtained by a modified co-thermolysis method. Detailed investigations the excitation and relaxation mechanisms ions in such NCs are reported. Based on photoluminescence excitation, absorbance, emission decay times measured as function wavelengths, it shown that two sites with characteristics present case NCs. It that, when concentration increases, strong ion-ion...

Upconversion (UC) luminescence in doped lanthanide nanocrystals is associated with the energy migration (EM) process within clusters of dopant ions. The synthesis core-shell occurs at elevated temperatures, promoting diffusion dopants into shell accompanied by decay clusters. details this unwanted effect are poorly understood. In paper, we theoretically study a model ions nanocrystal using Monte Carlo (MC) simulations. We characterize diffusion, spatial neighboring relations and clustering...

ABSTRACT Cytochrome cbb 3 -type oxidases are members of the heme copper oxidase superfamily and composed four subunits. CcoN contains b -Cu B binuclear center where oxygen is reduced, while CcoP CcoO membrane-bound c cytochromes thought to channel electrons from donor cytochrome into center. Like many other bacterial this superfamily, a fourth, non-cofactor-containing subunit, which termed CcoQ. In present study, we analyzed role CcoQ on stability activity Rhodobacter capsulatus oxidase. Our...

In this work we report the synthesis of hexagonal upconverting nanocrystals, NaGdF₄:Yb³⁺,Er³⁺, in a wide range sizes (20–120 nm) by changing Yb³⁺ and Er³⁺ concentration. Effect ions concentration their interaction was investigated.

We present a design of an infrared cylindrical cloak using nanosphere dispersed nematic liquid crystal (NLC) metamaterial following the approach Smith's group [Science 314, 977 (2006)]. Cloaking conditions require spatial distribution birefringence with constant extraordinary index refraction and radially dependent ordinary refraction. An approximate analytical formula for latter is derived. Finite element (FE) simulations confirm cloaking effect. Owing to tunable component, such material...

Malaria is a major health burden in tropical and subtropical countries. The antimalarial drug primaquine extremely useful for killing the transmissible gametocyte forms of Plasmodium falciparum hepatic quiescent P. vivax. Yet its mechanism action still poorly understood. In this study, we used yeast Saccharomyces cerevisiae model to help uncover mode primaquine. We found that growth inhibitory effect was restricted cells relied on respiratory function proliferate deletion SOD2 encoding...

We show that nanosphere dispersed liquid crystal (NDLC) metamaterial can be characterized in near IR spectral region as an indefinite medium whose real parts of effective ordinary and extraordinary permittivities are opposite signs. Based on this fact we designed electro-optic effect: external electric-field-driven switch between normal refraction, negative reflection TM incident electromagnetic wave from the boundary vacuum/NDLC. A detailed analysis its functionality is given based theory...

ABSTRACT Cytochrome oxidases are perfect model substrates for analyzing the assembly of multisubunit complexes because need cofactor incorporation adds an additional level complexity to their assembly. cbb 3 -type cytochrome c ( -Cox) consist catalytic subunit CcoN, membrane-bound subunits CcoO and CcoP, CcoQ subunit, which is required -Cox stability. Biogenesis proceeds via CcoQP CcoNO subcomplexes, assemble into active -Cox. Most bacteria expressing also contain ccoGHIS genes, encode...

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

We study theoretically the possible origin of a double-peak fine structure Surface Relief Gratings in azo-functionalized poly(etherimide) reported recently experiments. To improve statistics experimental data additional measurements were done. For theoretical analysis we develop stochastic Monte Carlo model for photoinduced mass transport azobenzene-functionalized polymer matrix. The long sought-after chains from bright to dark places illumination pattern is demonstrated and characterized,...

Monte Carlo studies of the field-induced complex refractive index changes in nano-dispersed nematic liquid crystals (NLCs) exhibiting negative-positive indices have been performed for various cases applied field strengths and anchoring conditions over a broad spectral regime. The resultant spatially inhomogeneous molecular order corresponding metamaterial properties are obtained wavelengths below above Freedericksz transition. In general, director axis reorientation distribution...

Chemical synthesis and concentration dependence of two second order NLO tensor components: was studied for a side chain polymer PMMA-DR1 in thin films by optical harmonic generation techniques. The noncentrosymmetry created the corona poling technique. results show that small chromophore concentrations susceptibility follows linearly density number active chromophores, reaches maximum, than decreases stabilizes.

Based on single nanocrystals optical studies and numerical simulations, the optimal Yb³⁺ Er³⁺ concentration in NaYF₄ upconverting has been explained as due to percolation threshold lost of excitation energy at NCs surface.

The physical processes accompanying an illumination of azobenzene chromophores embedded in a polymer matrix with spatially modulated and linearly polarized light are studied experimentally simulated using the Monte Carlo (MC) method. MC simulations base on simple three-channel kinetic model trans-cis type photoisomerization cycles azobenezene molecules. method focus studying kinetics diffraction grating recording erasing under various conditions illumination, polarization presence or absence...

We study theoretically the kinetics of noninteracting photoswitchable guest molecules (model azo-dye) dispersed at low concentration in host polymer matrix) all-optical poling process close to glass transition temperature Tg. modify kinetic Monte Carlo model used our previous studies nonlinear optical processes host-guest systems. The matrix is simulated using bond-fluctuation model. multiple trans-cis-trans cycles formulated terms probabilities which depend on local free volume and its...

The microscopic and semi-macroscopic mechanisms responsible for photoinduced mass transport in functionalized azo-polymers are far from deeply understood. To get some insight into those on "microscopic" scale, we studied the directed motion of single polymer chains under various types polarized light illumination using Monte Carlo bond fluctuation model our kinetic transport. We found sub-diffusive, diffusive super-diffusive regimes dynamics at constant mostly regime presence gradient...

In this work, we report the results of theoretical modeling supported and confirmed by experimentally measured emission, emission decay curves, power dependent spectra for sub 10 nm β-NaGdF4:Er3+,Yb3+ nanocrystals with different Yb3+ content (0.5%-15%). For analysis, develop a stochastic Monte Carlo model which is based on two components: (i) formation clusters composed Er3+ ion neighbors, gives insight into role local parameters (ii) simplified kinetic excitation relaxation phenomena in...

A simple kinetic model of temperature-dependent processes accompanying the writing and decay diffraction gratings in a polymer matrix doped with azo-dye chromophores under illumination spatially modulated linearly polarized light is introduced studied using Monte Carlo simulations. The generalizes recently proposed athermal based on three-channel photoizomerization cycles trans–cis type azobenzene molecules orientational redistribution diffusion. These are influenced by thermal equilibrium....

Abstract We study experimentally the dynamics of holographic inscription gratings in DR1:DNA-CTMA thin films using a degenerate two-wave mixing (DTWM) setup its initial phase (30 ms) and longer time interval s). The temporal pattern evolution diffraction efficiency is complex, simple fitting procedures fail to reproduce data. point out that complex can originate large span scales, closely related microscale inhomogeneity local free volume. Some hallmarks are found through Monte Carlo simulations.