Synthesis and characterization of neodymium oxide modified nafion membrane for direct alcohol fuel cells

Nafion composite membranes were prepared by incorporating neodymium oxide (Nd₂O₃), a hygroscopic rare earth oxide and a dopant for H⁺ ion conduction, into the nafion structure. Five different loadings of Nd₂O₃ were used to fabricate Nd₂O₃/nafion composite membranes and characterized extensively for possible use in direct alcohol fuel cells. The proton conductivity, ion exchange capacity, water uptake, tensile strength, and oxidation stability of the composite membrane were higher than pure cast nafion membrane. Nd₂O₃/nafion composite membrane exhibited reduced methanol and ethanol crossover as compared to pure cast nafion membrane and thus has potential to use in direct alcohol fuel cells.     

Evaluating and automating the annotation of a learner corpus

The paper describes a corpus of texts produced by non-native speakers of Czech. We discuss its annotation scheme, consisting of three interlinked tiers, designed to handle a wide range of error types present in the input. Each tier corrects different types of errors; links between the tiers allow capturing errors in word order and complex discontinuous expressions. Errors are not only corrected, but also classified. The annotation scheme is tested on a data set including approx. 175,000 words with fair inter-annotator agreement results. We also explore the possibility of applying automated linguistic annotation tools (taggers, spell checkers and grammar checkers) to the learner text to support or even substitute manual annotation.     

Synthetic Polyamine BPA‐C8 Inhibits TGF‐β1‐Mediated Conversion of Human Dermal Fibroblast to Myofibroblasts and Establishment of Galectin‐1‐Rich Extracellular Matrix in Vitro

Cancer‐associated fibroblasts (CAFs) play a role in the progression of malignant tumors. They are formed by conversion of fibroblasts to smooth muscle α‐actin‐positive (SMA‐positive) myofibroblasts. Polyamines are known to change the arrangement of the actin cytoskeleton by binding to the anionic actin. We tested the effect of the synthetic polyamine BPA‐C8 on the transition of human dermal fibroblasts to myofibroblasts induced either by TGF‐β1 alone or by TGF‐β1 together with adhesion/growth‐regulatory galectin‐1. Pre‐existing CAFs, myofibroblasts from pancreatitis, and rat smooth muscle cells were also exposed to BPA‐C8. BPA‐C8 impaired myofibroblast formation from activated fibroblasts, but it had no effect on cells already expressing SMA. BPA‐C8 also reduced the occurrence of an extracellular matrix around the activated fibroblasts. The reported data thus extend current insights into polyamine activity, adding interference with tumor progression to the tumor‐promoting processes warranting study.     

In situ co-adsorption of arsenic and iron/manganese ions on raw clays

The use of clays as effective arsenic sorbents has been strongly limited due to their low pH_ZPC and cation active behaviour in aqueous systems at pH > 3.5. A simple Fe/Al/Mn pre-treatment can significantly improve their sorption affinity to oxyanions, including arsenites and arsenates. The dynamics of arsenic adsorption from groundwater is also controlled by dissolved Fe/Mn ions, which behave as promoters of As adsorption, or competitors to adsorption sites. Low grade calcinated kaolin (MT) and bentonite (BT) were used as clay sorbents. Arsenic adsorption on raw clays without presence of Fe/Mn ions is very slow and limited. During co-adsorption the Fe/Mn ions and As oxyanions were adsorbed together onto a sorbent surface. Both Mn and Fe particles demonstrated a good sorption affinity to the clay surface, but only Fe particles supported As adsorption considerably (80% of As were removed in Fe/As system, while < 30% only in the Mn/As system). The kinetics of co-adsorption compared to the use of Fe/Mn pre-modified sorbents indicated a more dynamic process, while all mechanisms corresponded to the first order run (k ≈ 9.10^− 6- 1.10^− 4 s^− 1). Arsenic was strongly stabilized in pre-modified sorbents.