Toxic effects of anticancer drug doxorubicin to bovine serum albumin evaluated by spectroscopic methods

The aim of this present work is to investigate the interaction between doxorubicin and bovine serum albumin (BSA) in simulated physiological conditions by spectroscopic methods to reveal potential toxic effects of the drug. The results reflected that doxorubicin made the fluorescence quenching of BSA through a static quenching procedure. The binding constants at 293, 298, and 303 K were obtained as 2.53 × 10⁵, 8.13 × 10⁴, and 3.59 × 10⁴ M^–1, respectively. There may be one binding site of doxorubicin on BSA. The thermodynamic parameters indicated that the interaction between doxorubicin and BSA was driven mainly by hydrogen bonding and electrostatic forces. Synchronous fluorescence spectra and circular dichroism (CD) results showed doxorubicin binding slightly changed the conformation of BSA with secondary structural content changes. Förster resonance energy transfer (FRET) study revealed high possibility of energy transfer with doxorubicin-Trp-212 distance of 3.48 nm. The results of the present study may provide valuable information for studying the distribution, toxicological and pharmacological mechanisms of doxorubicin in vivo.     

Synthesis and electrochemical properties of regular hexahedron α-Fe2O3

Synthesis of α-Fe₂O₃ compound with regular hexahedron shape is firstly reported. X-ray diffraction and scan electron microscope are used to characterize the structure and morphology of the prepared sample, respectively. The average edge length of hexahedron is about 0.9 μm. A reaction mechanism has been proposed. The pH value is a crucial factor for the formation and shape of α-Fe₂O₃. Moreover, electrochemical impedance spectroscopy and charge-discharge test of α-Fe₂O₃ as anode material in lithium ion batteries are evaluated. The data indicate that the synthesized regular hexahedron α-Fe₂O₃ can show better electrochemical properties than that of the commercial.     

Effects of carbon contents on morphology and electrical properties of Li2MnSiO4/C prepared by a vacuum solid-state method

To improve the electrochemical performance of Li₂MnSiO₄ with low electric conductivity, the Li₂MnSiO₄/C composite are synthesized by a vacuum solid-state reaction of a mixture of SiO₂, LiCH₃COO, Mn(CH₃COO)₂ and designed mass of C₆H₁₂O₆ · H₂O as carbon sources. The crystalline structure and morphology of products are analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and laser scattering technology (LS) respectively. The tested results show that carbon doping decrease the crystallite sizes of products, but keep the aggregation of the particles and made the impurity increased instead. The results of constant current charge-discharge prove that the mixed carbon improve Li⁺ transmission performance and decrease inner polatization resistance of Li₂MnSiO₄ materials, but can not prevent the collapse of Li₂MnSiO₄ crystal structure. While the galvanostatic intermittent titration technique (GITT) results demonstrate that the primary reason for the improved electrochemical performance can be attributed to increased Li-ion diffusion coefficient $(D_{Li^ + } )$ as a result from carbon doping.     

Resonance Rayleigh scattering method for direct determination of polyacrylamide in water samples using basic phenothiazine dyes

Binding polyacrylamide (PAM) with some basic phenothiazine dyes such as methylene blue (MB), toluidine blue (TB) or Azure B (AB) etc. can result in a significant enhancement of resonance Rayleigh scattering (RRS). The maximum RRS wavelengths (λ_max) appear at 348, 340 and 342 nm for MB, TB, and AB systems, respectively. Accordingly, a new RRS method for the direct determination of PAM at nanogram levels has been established. The optimum conditions of these reactions, the influencing factors have been investigated. The RRS intensity is directly proportional to the concentration of PAM in the range of 0.040–5.0 μg/mL for three systems. The methods exhibit high sensitivities, and the detection limits are 15.9 ng/mL for MB system, 44.0 ng/mL for TB system, and 59.8 ng/mL for AB system. The selectivity of the method is investigated by using MB system owing to the highest sensitivity. Concentrations of PAM in tap water, synthetic water and practical waste water samples are determined satisfactorily. The reaction mechanism and RRS enhancement reasons are discussed.     

Hydrothermal syntheses and crystal structure of a novel one-dimensional Pb(II) coordination polymer with chenodeoxycholic acid ligand

A novel 1D chain-like coordination polymer, {[Pb(CDCA)₂(DMF)] · DMF · 2H₂O]} _n (I) (HCDCA = chenodeoxycholic acid, DMF = dimethyl formamide), has been synthesized by hydrothermal method and characterized by single crystal X-ray diffraction, IR spectroscopy, and elemental analysis (CIF file CCDC no. 996098). X-ray diffraction analyses indicated that I displays distorted octahedral metal centers with secondary building units [Pb(CDCA)₂(DMF)] bridged by a pair of μ²-COO^?-bridges. In the crystal, interchain O-H?O hydrogen bonds are present and assemble the neighboring 1D chain into a (4,4) sql type three-dimensional (3D) supramolecular topological network.