Selective collection of inorganic iron(III) colloids in water with oxine-impregnated water-in-oil emulsion

An oxine-impregnated emulsion was prepared by dissolving 100 mg of oxine and 0.3 ml of non-ionic surfactant (Span-80) in 10 ml of toluene and mixing with 3 ml of 1 mol l(-1) hydrochloric acid by sonication (20 kHz). The water-in-oil emulsion was injected into 50 ml of water sample (containing iron(III) at the ppb level, pH 4-7) and dispersed by stirring for 10 min as numerous small globules (0.1-0.5 mm in diameter). The iron diffused through the toluene layer into the small droplets of hydrochloric acid. The emulsion was separated by flotation and heated to segregate the aqueous (hydrochloric acid) and organic (toluene) phases. The iron in the aqueous phase was determined by graphite-furnace atomic absorption spectrometry (GFAAS). Hydrated iron(III) oxide having particle sizes of larger than 1 mum did not penetrate into the emulsion. Other iron species which were not incorporated into the emulsion include humic complexes and hybrid particles of hydrated iron(III) oxide and humic substances. This discrimination can be attributed to the surfactant layer at the oil-water interfaces and gentle stirring of the solution. The conventional liquid-liquid extraction, however, did not offer such a selectivity, because all iron(III) species were simultaneously extracted into the organic phase with vigorous shaking. The unique property of the emulsion method has been applied to the separation and determination of inorganic dissolved iron species in river water.     

Chemistry of renieramycins. Part 4.synthesis of a simple natural marine product, 6-hydroxy-7-methoxyisoquinolinemethanol

6-Hydroxy-7-methoxyisoquinolinemethanol (15) and mimosamycin (1) were recently isolated from a marine sponge, Haliclona sp. The former was prepared in ten steps from vanillin (22) in 26% overall yield using an isopropyl for phenol protection.     

Chemical Synthesis of Interleukin‐2 and Disulfide Stabilizing Analogues

Chemical protein synthesis allows the construction of well‐defined structural variations and facilitates the development of deeper understanding of protein structure–function relationships and new protein engineering strategies. Herein, we report the chemical synthesis of interleukin‐2 (IL‐2) variants on a multimilligram scale and the formation of non‐natural disulfide mimetics that improve stability against reduction. The synthesis was accomplished by convergent KAHA ligations; the acidic conditions of KAHA ligation proved to be valuable for the solubilization of the hydrophobic segments of IL‐2. The bioactivity of the synthetic IL‐2 and its analogues were shown to be equipotent to recombinant IL‐2 and exhibit improved stability against reducing agents.     

Formation of interpenetrated spherulites based on miscible crystalline polymer blends

The morphology and formation process of interpenetrated spherulites of poly(butylene succinate)/poly(vinylidene choloride‐co‐vinyl chloride) (PBSU/PVDCVC) blends were investigated by confocal laser scanning microscopy (CLSM). CLSM images showed that the dense fibrils of PBSU spherulites penetrated into the sparse PVDCVC spherulites. For a blend with PBSU content 50% and crystallization temperature T_c = 368 K, the simultaneous growth of PBSU and PVDCVC spherulites was observed. After PBSU fibrils collided with PVDCVC spherulites, they kept growing through PVDCVC spherulites. For a blend with PBSU content 30% and T_c = 363 K, PBSU started to nucleate after PVDCVC spherulites filled the whole space.