Colloidal synthesis of Sb2S3 nanorods/bars with strong preferred orientation

We report the synthesis of antimony trisulfide (Sb₂S₃) nanorods/bars via a simple, low-cost and colloidal synthetic method. The as-synthesized Sb₂S₃ nanorods/bars with different heating times from the moment of appearance of the Sb₂S₃ precipitate at 240 °C are the longest and thinnest in the beginning (diameters of 50-100 nm and lengths of 3-5 μm). UV/Vis absorption spectroscopy reveals that the optical band gap energy of the Sb₂S₃ nanorods/bars slightly decreases with increasing the heating times in the range of 1.54, 1.50 to 1.47 eV at the red part of the solar spectrum. The structure of Sb₂S₃ for all free samples was refined down to the R-factor of 9.57, 5.43 and 6.19%. The refinement showed that Sb₂S₃ powder belongs to the orthorhombic type with space group Pbnm (no. 62). It was found that Sb₂S₃ nanorods/bars predominantly grow along the [010] direction. The preferred orientation parameter (τ) refined against experimental data is quite high and is found to be 1.42, 1.21 and 1.19 for all three samples observed. A decrease in unit cell parameter b followed by increasing the heating times was observed.     

Ozone treatment ameliorates oil sands process water toxicity to the mammalian immune system

We evaluated whether ozonation ameliorated the effects of the organic fraction of oil sands process water (OSPW) on immune functions of mice. Ozonation of OSPW eliminated the capacity of its organic fraction to affect various mouse bone marrow-derived macrophage (BMDM) functions in vitro. These included the production of nitric oxide and the expression of inducible nitric oxide synthase, the production of reactive oxygen intermediates and the expression of NADPH oxidase subunits, phagocytosis, and the expression of pro-inflammatory cytokine genes. Ozone treatment also eliminated the ability of OSPW organic fraction to down-regulate the expression of various pro-inflammatory cytokine and chemokine genes in the liver of mice, one week after oral exposure. We conclude that ozone treatment may be a valuable process for the remediation of large volumes of OSPW.     

Synthesis,characterization, and antifungal activity of nystatin—gum arabic conjugates

Nystatin, a polyene tetraene antibiotic widely used in the treatment of mycoses, was coupled with oxidized polysaccharide gum Arabic, by forming Schiff base structures between amine groups of antibiotics and aldehyde groups of modified carbohydrate. Imine conjugates synthesized in this way were reduced with sodium borohydride to secondary amines. Two imine and two amine conjugates were obtained with different nystatin content. The conjugates were characterized by UV–Vis, FTIR, ¹H NMR spectroscopy, and thermogravimetric analysis. Solubility in water, unlike nystatin, and significant activity against Candida albicans and Aspergillus niger with minimum inhibitory concentrations in range of 3.125–6.25 μg mL^?1 and 6.25–25 μg mL^?1, respectively, indicate that the chemical integrity and the biological function of these compounds were retained. A comparison of stability of the conjugates in the dry form, solution and under different pH values showed that the conjugates exhibited better stability than pure drug. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Derivation, growth and applications of human embryonic stem cells

Human embryonic stem (hES) cells are pluripotent cells derived from the inner cell mass cells of blastocysts with the potential to maintain an undifferentiated state indefinitely. Fully characterised hES cell lines express typical stem cell markers, possess high levels of telomerase activity, show normal karyotype and have the potential to differentiate into numerous cell types under in vitro and in vivo conditions. Therefore, hES cells are potentially valuable for the development of cell transplantation therapies for the treatment of various human diseases. However, there are a number of factors which may limit the medical application of hES cells: (a) continuous culture of hES cells in an undifferentiated state requires the presence of feeder layers and animal-based ingredients which incurs a risk of cross-transfer of pathogens; (b) hES cells demonstrate high genomic instability and non-predictable differentiation after long-term growth; and (c) differentiated hES cells express molecules which could cause immune rejection. In this review we summarise recent progress in the derivation and growth of undifferentiated hES cells and their differentiated progeny, and the problems associated with these techniques. We also examine the potential use of the therapeutic cloning technique to derive isogenic hES cells.     

Prediction of flyrock trajectories for forensic applications using ballistic flight equations

The paper presents a method for determination of the maximum throw of flyrock fragments and the estimation of safe distances. The method is based upon formulation and solution of differential equations of ballistic flight of the flyrock fragments. The equations are formulated according to Newton's law of motion. Two possible solutions are presented, an approximate numerical solution and the application of the Runge–Kutta algorithm of the fourth order. As an illustration of the presented method a post-accidental forensic analysis case study is given describing the procedure for determination of the input parameters (especially the launch velocity).     

The improved photovoltaic response of commercial monocrystalline Si solar cell under natural and artificial light by using water flow lens (WFL) system

The performances of a photovoltaic system based on high‐efficiency commercial monocrystalline Si solar cell associated with the water flow lens (WFL) system are investigated. This system enables the cooling of the surface of the cell, indirectly cooling the surrounding, and, on the other hand, it allows us to investigate, depending on the position of the cell and the WFL system, the influence of larger and smaller intensities of the light with the inevitable change in the spectrum. All of these effects are very important and can greatly contribute to the better photovoltaic performance of the used cells. Indoor characterization at higher and lower light intensities is performed using both different spectra and intensity of the light. The obtained results show that at low/lower light intensity, spectra are more dominant than the intensity of light itself and that the used WFL system always improves the photovoltaic response leading to a higher efficiency of the tested solar cell. It was found that the ratios of the short circuit current (I_sc) and the input light energy (P_input) are 4.42 and 8.96 without and with the use of the WFL system in the measurements, respectively. The same Si solar cell is also tested in outdoor condition, but this time using the WFL system to concentrate sunlight to produce a larger amount of power and water flow for cooling the surface of the solar cell. Again, a higher efficiency (an increase from 25.7% to 33.5%) by using the WFL system was obtained.     

Growth of Sb2S3 nanowires synthesized by colloidal process and self-assembly of amorphous spherical Sb2S3 nanoparticles in wires formation

We report the organic synthesis and growth of antimony sulfide (Sb₂S₃) amorphous nanospheres to nanowires via a simple, colloidal synthetic method. Amorphous Sb₂S₃ nanospheres self-assembly in wires formation was dispersed in isopropyl alcohol. With increased heating time, Sb₂S₃ nanospheres grew into Sb₂S₃ nanowires, probably involving both mechanisms of Ostwald-ripening and spherical nanoparticle self-organization through oriented-attachment of individual nanoparticles. Also, the as-synthesized Sb₂S₃ nanowires with different heating times (0, 5 and 10 min.) from the moment of appearance of the Sb₂S₃ precipitate were analyzed. The observed nanowires become longer with increased heating time and are around 100 nm in diameter and 10?C20 ??m in length. UV-Vis absorption spectroscopy reveals that the optical band-gap energy of the Sb₂S₃ nanowires is independent of the heating times and is found to be ??1.5?C1.6 eV. The optical band-gap energy found for amorphous Sb₂S₃ nanospheres was also ??1.5 eV. The structure of Sb₂S₃ samples was refined down to R-factors of 10.82, 11.76 and 12.08%. The refinement showed that Sb₂S₃ powder belongs to the orthorhombic type with space group Pbnm (no. 62) and that Sb₂S₃ nanowires grow along the [010] direction.     

Efficient and novel Sb2S3 based solar cells with chitosan/poly(ethylene glycol)/electrolyte blend

We present here a novel solar cell made of ITO/composite p‐doped Sb₂S₃ + P3HT + PANI+TiO₂/amorphous Sb₂S₃ + P3HT + PANI + TiO₂/n‐doped Sb₂S₃ + P3HT + PANI + TiO₂/solid carrier/aluminum as counter electrode. With spraying technique, the layers were deposited and the thickness of films was 1 μm. A new solid carrier of electrolyte was a blend consisted of chitosan (low MW), polyethylene glycol and electrolyte. X‐ray diffraction was recorded to confirm the amorphous nature of the blend. Information about the surface appearance and roughness of a solid carrier dry and soaked in the electrolyte was given by atomic force microscopy. The solar cell was examined at very low and low light intensity (5% and 35% of sun, respectively), and at standard test conditions (100% of sun) using different light sources. The whole cell surface was 7.5 cm² while the illuminated part was 3 cm². Obtained results expressed for the illuminated surface showed the highest efficiency of 23.1% at 5% of sun while the efficiency of the cell was 2.9% at 35% of sun and only 0.75% at intensity of 100% of sun.     

Electrochemical and structural study on cycling performance of γ-LiV2O5 cathode

Electrochemical and structural properties of LiV₂O₅ cathode were investigated. Obtained by solid state reaction at high temperature the material crystallized as gamma polymorph phase, γ-LiV₂O₅. The gamma structure provides two crystallographic sites to accommodate lithium ions, Li1 and Li2 position. Lithium insertion at these two sites occurs at two respective voltages versus lithium metal: ~3.6 V (Li1) and ~2.4 V (Li2). Intercalation at Li1 position is reversible in both organic and aqueous electrolyte and provides stable cycling performance at the high voltage. On the contrary, sluggish insertion/removal of Li⁺ at Li2 sites causes unstable performance and significant storage capacity fade at lower voltages. Lithium diffusion 3d landscape was determined by bond valence calculations applied on the γ-LiV₂O₅ phase, as well as on the metastable phases of γ′-V₂O₅ and ζ-Li₂V₂O₅ that exist at high and low voltages respectively. The model was proposed based on inactivity of Li2 position of the metastable ζ-Li₂V₂O₅ phase which provides explanation for the observed storage capacity loss at low voltages.