Bioactive compounds from the scale insect fungus Conoideocrella tenuis BCC 44534

Eleven new compounds, including two quinone derivatives of bioxanthracene, conoideocrellones A (1) and B (2), two bioxanthracenes 3 and 4, four isocoumarins and isocoumarin glycosides 7–10, two phenolic compounds 16 and 17, and a diterpenoid compound, conoideocin A (18), were isolated from culture of the scale-insect pathogenic fungus Conoideocrella tenuis BCC 44534. Seventeen known compounds, compounds 5 and 6, ES-242-2 and its atropisomer, isocoumarins and isocoumarin glycosides 11–15, 3,4,6-trihydroxymellein, cis-4,6-dihydroxymellein, metarhizins A (19) and B (20), BR-050 (21), 5α,8α-epidioxy-24(R)-methylcholesta-6,22-dien-3β-ol, zeorin, and conoideocrellide A, were also isolated from this fungus. Structures of these compounds were elucidated by NMR and MS data analyses. Compound 4 was active against Plasmodium falciparum K1 (IC₅₀ 6.6?μg/mL), while it did not show cytotoxicity. Conoideocrellone A (1) and compounds 3 and 7 exhibited cytotoxic activity, while conoideocin A (18) showed broad range of biological activities including antimalarial, antibacterial, and cytotoxic activities.     

Salicylaldehyde and dihydroisobenzofuran derivatives from the marine fungus Zopfiella marina

Two salicylaldehyde derivatives (1 and 2), a hydroxymethylphenol (3), five dihydroisobenzofuran (4–8) derivatives, and a 5-chloro-3-deoxyisoochracinic acid (9), together with a known 3-deoxyisoochracinic acid (10) were isolated from the marine fungus Zopfiella marina BCC 18240 (or NBRC 30420). The structures of these compounds were elucidated by extensive spectroscopic analysis. Compound 1 showed weak antituberculous activity against Mycobacterium tuberculosis H37Ra, and antibacterial activity against Bacillus cereus with MIC values of 25 and 12.5 μg/mL, respectively.     

Nanofibers of barium strontium titanate (BST) by sol-gel processing and electrospinning

This paper describes the fabrication of barium strontium titanate (Ba0.6Sr0.4TiO3 or BST) nanofibers by electrospinning method using a solution that contained poly(vinylpyrrolidone) and a sol-gel solution of BST. The as-spun and calcined BST/PVP composite nanofibers were characterized by TG-DTA, X-ray diffraction, FT-IR, SEM and TEM, respectively. After calcination of the as-spun BST/PVP composite nanofibers at above 700 degrees C in air for 2 h, BST nanofibers of 188+/-25 nm in diameter having well-developed cubic-perovskite structure were successfully obtained. The crystal structure and morphology of the nanofibers were influenced by the calcination temperature. Calcination at below 700 degrees C resulted in amorphous phase whereas BST with second phase such as barium titanate were formed at above 700 degrees C. Diameters of the nanofibers decreased from 208+/-35 to 161+/-18 nm with increasing calcination temperature between 600 and 800 degrees C.     

Effects of Water and Chemical Solutions Ageing on the Physical,Mechanical, Thermal and Flammability Properties of Natural Fibre-Reinforced Thermoplastic Composites

Biocomposites comprising a combination of natural fibres and bio-based polymers are good alternatives to those produced from synthetic components in terms of sustainability and environmental issues. However, it is well known that water or aqueous chemical solutions affect natural polymers/fibres more than the respective synthetic components. In this study the effects of water, salt water, acidic and alkali solutions ageing on water uptake, mechanical properties and flammability of natural fibre-reinforced polypropylene (PP) and poly(lactic acid) (PLA) composites were compared. Jute, sisal and wool fibre- reinforced PP and PLA composites were prepared using a novel, patented nonwoven technology followed by the hot press method. The prepared composites were aged in water and chemical solutions for up to 3 week periods. Water absorption, flexural properties and the thermal and flammability performances of the composites were investigated before and after ageing each process. The effect of post-ageing drying on the retention of mechanical and flammability properties has also been studied. A linear relationship between irreversible flexural modulus reduction and water adsorption/desorption was observed. The aqueous chemical solutions caused further but minor effects in terms of moisture sorption and flexural modulus changes. PLA composites were affected more than the respective PP composites, because of their hydrolytic sensitivity. From thermal analytical results, these changes in PP composites could be attributed to ageing effects on fibres, whereas in PLA composite changes related to both those of fibres present and of the polymer. Ageing however, had no adverse effect on the flammability of the composites.     

Vibrational spectroscopy of self‐assembling aromatic peptide derivates

Peptides can assemble to supramolecular structures, of which fibers are of special biochemical and medical relevance. We employed Raman and infrared spectroscopy to elucidate the chemical integrity of fibers built from peptides and peptide derivates that contain the aromatic side groups fluorenyl and phenyl. Because the observed spectra compare very well with simulation results of the respective single molecules in vacuum, we were able to assign all observed vibrations. We found the main differences between solid phase and single molecule for O‐H and N‐H stretching and bending vibrations, owing to hydrogen bonding in solids. The fluorenyl and phenyl residues cause π‐stacking of the molecules, which barely manifests in the spectra, but clearly in the structures. Whereas hydrogen bonds provide the principal stability of the fiber backbone, aromatic π‐stacking supports the assembly to fibers, especially when electrospinning assists the molecular alignment. Copyright © 2012 John Wiley & Sons, Ltd.