Investigation of a liposomal oxaliplatin drug formulation by capillary electrophoresis hyphenated to inductively coupled plasma mass spectrometry (CE-ICP-MS)

A capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS) method was developed for separation of the free oxaliplatin drug substance from liposome-entrapped oxaliplatin. Simultaneous determination of phosphorous and platinum opened the possibility to simultaneously monitor the liposomes (phospholipids) and platinum-based drug. In order to suppress the interferences, argon gas was used as a collision gas in ICP-MS. A detection limit of 29 ng/mL of platinum and a precision of 2.9% (for 10 μg/mL of oxaliplatin standard) were obtained. Measurement of the total concentration of free and encapsulated oxaliplatin by CE-ICP-MS was compared with total determination by ICP-MS after microwave digestion and showed a good agreement. A liposomal formulation of oxaliplatin based on PEGylated liposomes was used as a model drug formulation. Studies of accelerated drug release induced by sonication and phospholipase A₂ catalyzed hydrolysis were performed. It was demonstrated that the CE-ICP-MS was an efficient in vitro characterization method in the development and quality assurance purposes of lipsome-based formulation of metallodrugs.     

Electrical properties of PbxSn1‐xS thin films prepared by hot wall deposition method

The Pb_xSn_1‐xS (x = 0 – 0.25) thin films were prepared on glass substrates by hot wall vacuum deposition. The films were polycrystalline monophase in nature and had orthorhombic crystal structure. The thickness of the films was about 2‐3 μm. The temperature dependences of the conductivity were measured in the temperature range from 150 to 420 K. The films revealed p‐type of conductivity. The Seebeck coefficient and conductivity values of the films was in the range of α = 6 – 360 μV/K and σ = 4.8×10^‐5 – 1.5×10^‐2 Ω^‐1·cm^‐1, respectively, at room temperature depending on concentration of the lead in the films. The lead atoms created the substitution defects Pb_Sn in the crystal lattice of the Pb_xSn_1‐xS. These defects formed the donor energy levels in the band gap. The activation energy of the films increased in the range ΔE_a = 0.121 – 0.283 eV with increasing of the lead concentration. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Thermal expansion and structural properties of (CuAlTe2)1–x(CuAlSe2)x solid solutions

Investigations of the thermal expansion of (CuAlTe₂)_1–x(CuAlSe₂)_x solid solutions in the temperature range from 100 to 800 K have been carried out for the first time. It has been demonstrated that the thermal expansion coefficient α_L grows considerably in the temperature range from 100 to 300 K, whereas the temperature dependence above 300 K is rather weak. The isotherms of composition dependence of the thermal expansion coefficient α_L for 100, 293, 500 and 800 K were constructed, and it was found that linear relations could express them. The Debye temperatures θ_D , the average mean‐square dynamic displacements , the average root‐mean‐square amplitudes of thermal vibration RMS , the anion position parameter u using S. C. Abrahams & J. L. Bernstein (u_AB ) and J. E. Jaffe & A. Zunger (u_JZ ) models were calculated. The composition dependence of microhardness H using the phenomenological theory was also calculated, and it was discovered that this dependence has a non‐linear character with a maximum of 383 kg/mm² at x=0.67. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Stabilization of an optical cavity containing a birefringent element

A locking scheme for optimizing the length of an optical cavity containing a birefringent crystal is presented. This scheme is a variation on the well known polarization sensitive locking scheme. The birefringence of the crystal introduces a polarization dependent phase difference which can be used to generate a locking signal. The principles of the locking system are described and verified experimentally.     

Dual-orthogonal polynomials

Let (x, ) and (x,) be two functions,x[a, b] and { _j } _j=1 and { _j } _j=1 be two sequences where _{i j} and _{i j} whenij. We define the vector spacesU _k =span{(x, _j )} _j=1 ^k andV _k =span{(x, _j )} _j=1 ^k where we assume thatdim(U _k )=dim(V _k )=k,k1. We then look for the generalized polynomialsp _m xU _m+1\U _m so that _a ^b p _m (x)(x, _j )d(x)=0,j=1,2,...,m. If such generalized polynomials exist for allm1 we say that {p _m } _m=1 is a dual-orthogonal polynomial sequence from {(x, _j )} _j=1 to {(x, _j )} _j=1 with respect to the distribution (x),x[a, b]. In this article we present existence theorems for dual-orthogonal polynomials, explicit formulae forp _m(x), theorems about the zeros ofp _m(x), and, in the end, a Gauss-type quadrature formula for dual-orthogonal polynomials.     

Epitaxial Sn1‐xPbxS nanorods on iso‐compositional thin films

Based on SnS (Herzenbergite) – SnPbS₂ (Teallite) mixed crystals with orthorhombic layer structures, thin films and lawns of Sn_1‐xPb_xS nanorods were produced using hot wall vacuum deposition method (HWVD). The lawn was formed onto the surface of an underlying thin Sn_1‐xPb_xS film which is build by differently oriented blocks. The density of rods arranged like a lawn depends on the metal ratio and substrate temperature. X‐ray and TEM analysis of the epitaxial material showed preferential (001) orientation perpendicular to the surface of the glass substrate. The roughness of the films measured by atomic force microscopy was in the range of R_q = 49.5–86.3 nm depending on lead concentration The rods were about 500 nm high and 300 nm in diameter. As revealed by TEM‐EDX experiments the droplet at the tip of rods consists of tin. Therefore it is assumed the rods grew via a self‐consuming vapor–liquid–solid (VLS) mechanism. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

THE ENHANCEMENT OF PHYTOCHROME ACTION ON BARLEY LEAF UNFOLDING BY INTERMITTENT LIGHT

Abstract. The phytochrome controlled unfolding of etiolated barley leaves proceeds best if orange light (0.6 J/m²/s; 625 ± 25 nm) is given as two appropriately timed short pulses rather than as a single longer light period.     

Growth and Characterisation of (CuInTe2)1‐x(2 ZnTe)x Solid Solution Single Crystals

The crystal structure as well as the optical properties in the band gap region of (CuInTe₂)_1‐x(2 ZnTe)_x solid solution single crystals grown by directional freezing have been studied. The lattice constants exhibit a linear dependence on crystal composition. The chalcopyrite‐sphalerite phase transition was observed between x = 0.3 and x = 0.4°. The variation of the band gap with respect to crystal composition can be described by a quadratic expression.