Nickel,copper and manganese hexacyanoferrate with poly(3,4-ethylenedioxythiophene) hybrid film modified electrode for selectively determination of ascorbic acid

The NiHCF-PEDOT, CuHCF-PEDOT and MnHCF-PEDOT films were prepared on glassy carbon electrode (GCE) by multiple scan cyclic voltammetry and characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) techniques. The advantages of these films are demonstrated for selectivity detection of ascorbic acid using cyclic voltammetry and amperometric method. Interestingly, the NiHCF-PEDOT and CuHCF-PEDOT modified electrodes exhibited a wide linear response range (5 × 10⁻⁶−3 × 10⁻⁴ M, R ² = 0.9973 and 1.8 × 10⁻³−1.8 × 10⁻² M, R ² = 0.9924). The electrochemical sensors facilitated the oxidation of AA but not responded to other electroactive biomolecules such as dopamine, uric acid, H₂O₂, glucose. The difference is MnHCF-PEDOT/GCE that no response to AA. In addition, the NiHCF-PEDOT and CuHCF-PEDOT modified electrodes exhibited a distinct advantage of simple preparation, specificity, stability and reproducibility.     

An efficient 3C-silicon carbide/titania nanocomposite photoelectrode for dye-sensitized solar cell

Dye-sensitized solar cells (DSSCs) are fabricated using a novel 3C-SiC/TiO(2) nanocomposite as a photoelectrode to enhance the power conversion efficiency. Compared with a pristine nanocrystalline TiO(2) cell, a DSSC based on a 3C-SiC (0.04 wt%)/TiO(2) nanocomposite photoelectrode shows ~115% increase in power conversion efficiency.     

Extraction equilibrium of indium(III) from nitric acid solutions by di(2-ethylhexyl)phosphoric acid dissolved in kerosene

The extraction equilibrium of indium(III) from a nitric acid solution using di(2-ethylhexyl) phosphoric acid (D2EHPA) as an acidic extractant of organophosphorus compounds dissolved in kerosene was studied. By graphical and numerical analysis, the compositions of indium-D2EHPA complexes in organic phase and stoichiometry of the extraction reaction were examined. Nitric acid solutions with various indium concentrations at 25 °C were used to obtain the equilibrium constant of InR? in the organic phase. The experimental results showed that the extraction distribution ratios of indium(III) between the organic phase and the aqueous solution increased when either the pH value of the aqueous solution and/or the concentration of the organic phase extractant increased. Finally, the recovery efficiency of indium(III) in nitric acid was measured.     

MALDI-mass spectrometry imaging of desalted rat brain sections reveals ischemia-mediated changes of lipids

Ischemia-mediated lipidomic changes in rat brains were explored by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) profiling and imaging after in situ desalting which drastically simplified the spectral presentation of tissue lipids. Removal of interference from the massively changed cations in response to tissue damage permitted the revelation of subtle yet important lipidomic changes. The identities of the detected lipids were confirmed by MALDI tandem mass spectrometry (MALDI-MS/MS). The MALDI-MS imaging (MALDI-MSI) result of lysophosphatidylcholine 16:0 (LPC 16:0) in the desalted brain section appeared essentially identical to that of sodiated LPC 16:0 in the adjacent undesalted section and verified the suitability of the desalting method for the MALDI-MSI studies of lipids in tissue. Other than the consistently decreased phosphatidylcholine (PC) 16:0/18:1, images of PCs containing all saturated, or combined saturated and monounsaturated fatty acyl (MUFA) residues revealed their parenchymal increase by ischemia. Images of PCs containing polyunsaturated fatty acyl (PUFA) residues in normal cortex showed laminated patterns similar to cortical lamina. Ischemia reduced the abundance of PC 16:0/20:4 and PC 16:0/22:6 and disrupted the laminated distribution of the former. However, ischemia increased the subcortical abundance of PUFA-PCs containing stearoyl residue and confined their cortical increase within limited areas. Image of parenchymal sphingomyelin 18:0 (SM 18:0) showed its consistent decrease by ischemia that paralleled the increase of ceramide 18:0-H(2)O in region of moderate to high SM abundance. The above results presented the lipidomic changes largely different from previous MALDI-MSI results and suggested a window of intervention that may benefit the management of cerebrovascular accident and other brain injuries.     

Synthesis and Characterization of Cationic Glycidyl-Based Poly(aminoester)-Folic Acid Targeting Conjugates and Study on Gene Delivery

A new poly(aminoester) (EPAE-FA) containing folic acid and amino groups in the backbone and side chain was synthesized. EPAE-FA self-assembled readily with the plasmid DNA (pCMV-βgal) in HEPES buffer and was characterized by dynamic light scattering, zeta potential, fluorescence images, and XTT cell viability assays. To evaluate the transfection effect of graft ratio of FA on the EPAE system, EPAE-FA polymers with two different graft ratios (EPAE-FA12k and EPAE-FA14k) were also prepared. This study found that all EPAE-FA polymers were able to bind plasmid DNA and yielded positively charged complexes with nano-sized particles ( < 200 nm). To assess the transfection efficiency mediated by EPAE and EPAE-FA polymers, we performed in vitro transfection activity assays using FR-negative (COS-7) and FR-positive (HeLa) cells. The EPAE-FA12k/DNA and EPAE-FA14k/DNA complexes were able to transfect HeLa cell in vitro with higher transfection efficiency than PEI25k/DNA at the similar weight ratio. These results demonstrated that the introduction of FA into EPAE system had a significant effect on transferring ability for FR-positive cells (HeLa). Examination of the cytotoxicity of PEI25k and EPAE-FA system revealed that EPAE-FA system had lower cytotoxicity. In this paper, EPAE-FA seemed to be a novel cationic poly(aminoester) for gene delivery and an interesting candidate for further study.