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Two-step Protocol (two-step + protocol)
Selected AbstractsUtilization of Hypervalent Iodine in Organic Synthesis: A Novel and Facile Two-Step Protocol for the Synthesis of New Derivatives of 1H-Imidazo[1,2-b]pyrazole by the Cyclocondensation Involving ,-Tosyloxyacetophenones.CHEMINFORM, Issue 32 2005Ming Li No abstract is available for this article. [source] Applying forest restoration principles to coral reef rehabilitationAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2003N. Epstein Abstract 1.Forest restoration through silviculture (gardening) programs revives productivity, biodiversity, and stability. As in silviculture approaches, the coral ,gardening' strategy is based on a two-step protocol. 2.The first step deals with the establishment of in situ and/or ex situ coral nurseries in which corals are farmed (originating from two types of source material: asexual [ramets, nubbins], and sexual [planula larvae, spat] recruits). 3.The second is the reef rehabilitation step, where maricultured colonies are transplanted into degraded sites. 4.We compare here the rationale of forest restoration to coral reef ecosystem restoration by evaluating major key criteria. As in silviculture programs, a sustainable mariculture operation that focuses on the prime structural component of the reef (,gardening' with corals) may promote the persistence of threatened coral populations, as well as that of other reef taxa, thus maintaining genetic diversity. In chronically degrading reef sites this may facilitate a halt in biodiversity depletion. 5.Within the current theoretical framework of ecosystem restoration, the recovery of biodiversity indices is considered a core element since a rich species diversity provides higher ecosystem resilience to disturbances. 6.The gardening measure may also be implemented worldwide, eliminating the need to extract existing colonies for transplantation operations. At degraded reef sites, the coral gardening strategy can assist in managing human and non-human stakeholders' requirements as is done in forest management. Copyright © 2003 John Wiley & Sons, Ltd. [source] Two-step counterdiffusion protocol for the crystallization of haemoglobin II from Lucina pectinata in the pH range 4,9ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 3 2010Carlos A. Nieves-Marrero Lucina pectinata haemoglobin II (HbII) transports oxygen in the presence of H2S to the symbiotic system in this bivalve mollusc. The composition of the haem pocket at the distal site includes TyrB10 and GlnE7, which are very common in other haem proteins. Obtaining crystals of oxyHbII at various pH values is required in order to elucidate the changes in the conformations of TyrB10 and GlnE7 and structural scenarios induced by changes in pH. Here, the growth of crystals of oxyHbII using the capillary counterdiffusion (CCD) technique at various pH values using a two-step protocol is reported. In the first step, a mini-screen was used to validate sodium formate as the best precipitating reagent for the growth of oxyHbII crystals. The second step, a pH screen typically used for optimization, was used to produce crystals in the pH range 4,9. Very well faceted prismatic ruby-red crystals were obtained at all pH values. X-ray data sets were acquired using synchrotron radiation of wavelength 0.886,Å (for the crystals obtained at pH 5) and 0.908,Å (for those obtained at pH 4, 8 and 9) to maximum resolutions of 3.30, 1.95, 1.85 and 2.00,Å for the crystals obtained at pH 4, 5, 8 and 9, respectively. All of the crystals were isomorphous and belonged to space group P42212. [source] Electroactive Linear,Hyperbranched Block Copolymers Based on Linear Poly(ferrocenylsilane)s and Hyperbranched Poly(carbosilane)sCHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2009Frederik Wurm Dipl.-Chem. Abstract A convenient two-step protocol is presented for synthesis of linear-hyperbranched diblock copolymers consisting of a linear, organometallic poly(ferrocenylsilane) (PFS) block and hyperbranched poly(carbosilane) (hbPCS) segments. Linear PFS diblock copolymers were synthesized through photolytic ring-opening polymerization of dimethyl[1]silaferrocenophane as the first block and methylvinyl[1]silaferrocenophane as the second. These block copolymers served as polyfunctional cores in a subsequent hydrosilylation polyaddition of different silane-based AB2 monomers. Three AB2 monomers (methyldiallylsilane; methyldiundecenylsilane, and ferrocenyldiallylsilane) were investigated; they introduced structural diversity to the hyperbranched block and showed variable reactivity for the hydrosilylation reaction. In the case with the additional ferrocene moiety in the ferrocenyldiallylsilane monomer, an electroactive hyperbranched block was generated. No slow monomer addition was necessary for molecular-weight control of the hyperbranching polyaddition, as the core had much higher functionality and reactivity than the carbosilane monomers. Different block ratios were targeted and hybrid block copolymers with narrow polydispersity (<1.2) were obtained. All the resulting polymers were investigated and characterized by size exclusion chromatography, NMR spectroscopy, cyclic voltammetry, and TEM, and exhibited strongly anisotropic aggregation. [source] | ||||||||||