COMMUNICATIONSto understand the mechanism by which metal binding induces dispersion of the lipid aggregates and investigations of the generality of this type of sensor are underway. Experimental ProcedureStock lipid solutions were made by dissolving lipids and cholesterol (Sigma) in CHCI, (HPLC grade). Lipid I or 2 and a matrix lipid (DSPC, SOPC, or I:1 DSPC:cholesterol) were combined (5 mol% lipid I or 2 , 9 5 mol% matrix lipid) to give 10 pmol total lipid in l2mL volumetric centrifuge tubes. The lipid mixture was concentrated under aspirator vacuum, and 3 mL of MOPS buffer ( 2 0 m~ MOPS, 0.1 M NaCI. pH 7.5) was added to the tubes. The tubes were heated above 55°C and sonicated with a probe tip (Heat Systems model 375) for 15 min at 25-35% power under argon atmosphere in an ice bath. The vesicles were centrifuged at 11 000 rpm for 20 min to remove titanium particles. The phosphate concentration was determined for selected samples [15]. Vesicle sizes were measured by quasi-elastic light scattering by using a Microtrac Ultrafine Particle Analyzer (Leeds & Northrop) at 25 C in phosphate buffer. The mean diameter was 49 nm (59 nm distribution width) for unmetdlated vesicles. Vesicles were diluted 167-fold in MOPS buffer for metalbinding studies. Steady-state fluorescence measurements were performed at 25 "C on a temperature-controlled Shimadzu RF-450 spectrofluorimeter, excitation at 346 nin. 5 nm excitation and emission slit width.

Enhanced many-body interactions due to strong Coulomb interactions and quantum confinement are one of the most prominent features of two-dimensional systems. Auger process is a representative many-body interaction typically observed...

Isocyanates 7 were formed from monoprotected diamines 3 or 6, which in turn can be easily prepared from commercially available N-BOC- or N-FMOC-protected amino acid derivatives. Isocyanates 7, formed in situ, could be coupled directly to a solid support functionalized with amine groups or to amino acids anchored on resins using CH2Cl2 as solvent and an 11 h coupling time at 25 °C. Such couplings afforded peptidomimetics with an N-phthaloyl group at the N-terminus. The optimal conditions identified for removal of the N-phthaloyl group were to use 60% hydrazine in DMF for 1−3 h. Several sequences of amino acids coupled to ureas (“peptidic ureas”) and of sequential urea units (“oligoureas”) were prepared via solid phase syntheses and isolated by HPLC. Partition coefficients were measured for two of these peptidomimetics, and their water solubilities were found to be similar to the corresponding peptides. A small library of 160 analogues of the YGGFL-amide sequence was prepared via Houghten's tea bag methodology. This library was tested for binding to the anti-β-endorphin monoclonal antibody. Overall, this paper describes methodology for solid phase syntheses of oligourea derivatives with side chains corresponding to some of the protein amino acids. The chemistry involved is ideal for high-throughput syntheses and screening operations. The products can be expected to have an interesting range of pharmacological properties and enhanced proteolytic stabilities relative to the corresponding peptides.

The flow of melted mold powder into the interfacial gap between the strand and the mold wall is important for productivity and quality in continuous cast slabs. Some of the mold slag (flux) consumption provides true lubrication, while much of the rest is trapped in the oscillation marks on the slab surface. This work presents measurements of powder consumption from extensive careful plant trials on ultra-low carbon steels, and a new, simple, semi-empirical model to predict slag consumption. The model predicts "lubrication consumption" by deducting the slag carried in the oscillation marks from the measured total. The oscillation mark shape is estimated from a theoretical analysis of equilibrium meniscus shape, which is based on metallographic analysis of many hook and oscillation mark shapes. The model demonstrates that the fraction consumed in the oscillation marks decreases with increasing casting speed, because the oscillation mark depth depends more on casting speed than on mold oscillation conditions. The model is validated by successful prediction of known trends of oscillation mark depth and mold powder consumption with changing various operation parameters. The model provides new insight into mold lubrication phenomena, which is important for extending casting operation to higher speeds and new lubrication regimes.KEY WORDS: continuous casting; mold powder; slag; flux; lubrication; oscillation marks; mold oscillation; stroke; frequency; modification ratio; negative strip time; positive strip time; casting speed; meniscus; models; plant experiments.ISIJ International, Vol. 46 (2006), No. 11, pp. 1635No. 11, pp. -1644 slag as shown in Fig. 1(a). The solid slag layers are glassy, crystalline, or mixtures of both 14) depending on the slag composition and local cooling rate history. [15][16][17] Several previous models of heat transfer and lubrication assume that the gap has a uniform thickness. [18][19][20] However, the real strand surface contains periodic transverse depressions called oscillation marks (OM) in Fig. 1(b). The volume of these depressions generally consumes a significant amount of slag, which greatly affects lubrication and leads to nonuniform heat transfer in the mold. 21) Thus, quantifying the oscillation mark shape is a necessary prerequisite for the prediction of lubrication and heat transfer in the mold.In this study, mold powder consumption was measured during casting trials conducted at POSCO Gwangyang Works for several different oscillation conditions and casting speeds. The measured consumptions were divided into two components: 1) the slag entrapped in the oscillation marks and 2) the remaining flux, which provides lubrication to prevent sticking, as shown in Fig. 1(b). This "lubrication consumption" is a more realistic concept to represent lubrication than total mold powder consumption.17) The oscillation mark shape is calculated by combining measured OM depths with a realistic profile based on fundamentals. 22) Correlations are found for OM depth, corresponding OM consumption, l...