The optimal HLB for multiple emulsions was investigated and found dependent on the concns. of emulsifiers I and II. The shift of the optimal HLB at different emulsifier concns. is a result of the free emulsifier I which exists in the oil phase of the primary emulsion. A linear correlation between the optimal HLB, the concn. of emulsifier II, and the reciprocal concn. of emulsifier I is obsd. Yields of prepn. of the multiple emulsions were detd. by a chloride titrn. and cond. measurement, without using a dialysis cell. [on SciFinder(R)]
Photosensitized redn. of a series of dialkyl-4,4'-bipyridinium salts, CnV2+, with Cn alkyl of n = 1, 4, 6, 8, 14, and 18 was examd. in water-in-oil microemulsions, by using Ru(bpy)32+ (bpy = 2,2'-bipyridine) [15158-62-0] as sensitizer and (NH4)3 EDTA [15934-01-7] as electron donor. With the amphiphilic electron acceptors (n = 8-18) the water-in-oil microemulsion media effect the charge sepn. of the initial encounter cage complex, and stabilize the photoproducts, CnV+ and Ru(bpy)33+, against the recombination process. Consequently, enhanced quantum yields for CnV+. formation are obsd. under continuous illumination. [on SciFinder(R)]
Various cationic polyelectrolytes (poly-alpha-amino acids and histones), lectins, the chemotactic peptide, f-methionyl-leucyl-phenylalanine (fMLP), the calcium ionophore A23187, and phorbol myristate acetate (PMA) were investigated regarding their capacity to induce luminol-dependent chemiluminescence (LDCL) and superoxide production by human blood leukocytes. Although when tested individually, poly-L-arginine (PARG), phytohemagglutinin (PHA), concanavalin A (Con A), or fMLP induced only a low to moderate LDCL response, very intense synergistic CL reactions were obtained by mixtures of PARG + PHA, PARG + Con A, PARG + PHA + fMLP, Ca2 + ionophore + PARG + PHA + fMLP, and PARG + PMA. The sequence of addition of the various agents to WBC in the presence of luminol absolutely determined the intensity of the LDCL signals obtained, the highest reactions being achieved when the WBC were preincubated for 2-3 min with A23187 followed by the sequential addition of fMLP, PARG, and PHA. These "multiple hits" induced CL reactions which were many times higher than those obtained by each factor alone. On the other hand, neither poly-L-lysine, poly-L-ornithine, poly-L-histidine, nor poly-L-asparagine, when employed at equimolar concentrations, cooperated efficiently with PHA and fMLP to trigger synergistic LDCL responses in leukocytes. Concomitantly with the induction of LDCL, certain ligand mixtures also triggered the production of superoxide. The LDCL which was induced by the "cocktail" of agents was markedly inhibited by sodium azide (93% inhibition), but to a lesser extent by catalase (10% inhibition) or by superoxide dismutase (20%-60% inhibition). On the other hand, scavengers of singlet oxygen and OH (sodium benzoate, histidine) did not affect the synergistic LDCL responses induced by these multiple ligands. Cytochalasin B also markedly inhibited the LDCL responses induced either by soluble stimuli or by streptococci preopsonized either with histone or with polyanethole sulfonate. The LDCL responses which were induced by mixtures of PARG and concanavalin A were also strongly inhibited by mannose, alpha-methyl mannoside, and poly-L-glutamic acid. The data suggest that the LDCL responses induced by the soluble ligands involved a myeloperoxidase-catalyzed reaction. The possible employment of "cocktails" of ligands to enhance the bactericidal effects of PMNs, macrophages, and natural killer cells on microbial cells and mammalian targets is discussed.
The release of electrolytes from multiple emulsions can be a result of the instability of the multiple droplets or diffusion through the oil-layer membrane. It was confirmed exptl. that, in the multiple system examd., the diffusion mechanism is the detg. factor in the release pattern of these electrolytes. The release is affected by the hydrophobicity of the electrolyte and by its concn., but not by the viscosity of the internal phase. Therefore, from a practical point of view it is not enough to obtain stable multiple emulsions; limiting and controlling the diffusion has also to be considered. [on SciFinder(R)]
The photosensitized prodn. of chiral (-)-2-butanol is accomplished in a chem.-enzyme catalyzed-system in which ruthenium-tris-bipyridine, Ru(bipy)32+, photosensitizes the redn. of dimethyl-4,4'-bipyridinium (methylviologen, MV2+), and the sensitizer is recycled by oxidn. of (NH4)3EDTA. The primary reduced photoproduct, MV+·, mediates the redn. of NADP to NADPH in the presence of ferredoxin-NADP reductase. The final step in the cycle involves the redn. of 2-butanone by NADPH in the presence of alc. dehydrogenase. The optical purity of the formed (-)-2-butanol is 100%. The net reaction that corresponds to the redn. of 2-butanone by (NH4)3EDTA is an endoergic process by ∼33 kcal/mol EDTA consumed. [on SciFinder(R)]
There can be no doubt that of all issues of Coptic pattern grammar, it is the Nominal Sentence that has had the most monographic attention. Whatever the reasons for this special cultivation — the relative familiarity of this pattern set (known in similar forms from Egyptian and Semitic), its (again relative) compactness and transparency as regards internal structure and external relations of its constituents, the urge of typological interest in a verbless prediction pattern — the happy outcome is that today, although many details are still controversial, the patterns have been by and large isolated and their formal (if not always functional) analysis more or less agreed upon […]
The combination of optical fluorescence microscopy with digital image processing and analysis has been used to examine the three-dimensional organization of chromosomes within intact polytene nuclei. Although the arrangement indicates a high degree of flexibility, there are many conserved features between nuclei at the same developmental state. For example, chromosome arms are loosely coiled with centromeres clustered at the opposite end of the nucleus from the telomeres. Individual chromosome arms are not interwoven but occupy different spatial domains. Chromosomal sites that contact the envelope correlate with intercalary heterochromatin. Connections are observed between actively transcribing regions.
