Aggregates needle-like

An electron microscopy study by Mullen et al. (1989) showed that Cd2+, Cu2+ and La3+ accumulated on the cell surface of Bacillus cereus, B. subtilis, E. coli and Pseudomonas aeruginosa as needle-like, crystalline precipitates, while Ag+ precipitated as discrete colloidal aggregates at the cell surface and occasionally in the cytoplasm. The needle-like and hexagonal precipitates were also found for the biosorption of Ni2+ on the cell surface of P. fluorescens 4F39 at pH 9 and it was suggested as a microprecipitation process that followed on ion exchange (Lopez et al. 2000). 

In order to exploit the lipophilic core of the cylindrical aggregate, V,A, V",A "-tetrakis[2-hydroxy-1,1 -bis(hydroxymethyl)ethyl]hexadec-8-yne-l,l,16,16-tetracarboxamide was prepared this unsaturated ar-borol, possesses a centrally located alkyne moiety, and upon dissolution in water forms a gel comprised of a similar stacking motif to the saturated counterpart. The electron micrograph of this gel showed a unique aggregation pattern, in which bundles of intertwined aggregate columns were formed. The resultant, inherently helical pattern is in stark contrast to the needle-like structures formed by the related [9]-10-[9]-arborol. 

The fibrous crystals of C take up lithium preferably. Pure samples of C can be obtained readily in good yield from Li,Na gels. E, an important phase in the Li,Na system, appears as needle-like crystals or aggregates with a constant Si/Al ratio of 1. The potassium-exchanged form is identical with K-F, which was thought to be a typical product in the potassium field (5). Unexchanged crystals of E contain appreciable amounts of both Li and Na. 

Another shape of the solution structure that can exist in HT-PDDT consists of needle-like aggregates of extended chains of PT surrounded by a sheath of ordered alkyl chains. The needle-like aggregate structure does not possess a great deal of two-dimensional (2D) order, in constrast to the lamellar form. It is very interesting to note that the supramolecular ordering is greatest in HT-PDDT. The aggregation affects are much smaller in HT-PHT and intermediate in HT-POT. 

Mineral aggregates, simple organic liquids, and polymers [1-3] are common examples of spherulitic crystal pattern formation. The complex structure of spherulite is basically in the shape similar to needle-like crystal which is usually found in inorganic and organic materials, diverged from the center of the spherulite. The needle-like crystals are associated with the center of the spherulite to achieve a perfectly symmetrical shape. 

Fig. 10.10. Composition of organic soivents (methanoi) in the matrix soiution influences signal detection of lipids and peptides. Matrix solutions (containing 35 mg/ml DHB and 0.1 % TF/ of different ratios of water and methanol were prepared. Next, 0.5 p,l of each solution was applied to the section of mouse brain homogenate, which has homogeneous molecular distribution at any location of the section (n = 3). By increasing the methanol concentration, crystal form was also changed needle-like crystal, from which peptides were detected, was changed to the aggregate of smaller crystals from which lipids were detected.

Method of synthesis p-toluenesulfonic acid protonated aniline is used to make ani-linium complexes slow addition of ammonium peroxydisulfate caused formation of polyaniline in the mioelles and grew to needle-like aggregates potentially useful as conductive fillers Jung. W-H Kim, D-Y Lee. Y-M McCarthy, S P, Antec, 1786-90, 2006. 

It is well known that the Bruggeman EMA formula is derived by considering one of the constituents as a small sphere. A deviation from such an assumption required a modification the formula to include depolarization factor. Typically, a value of 0.333 is used as a default value in the EMA layer, which assumes a spherical shape of the inclusion. The other two extremes are 0, for a needle-like or columnar micro structure, and 1 for flat disks or a laminar microstructure. This type of transition was found for polyaniline/poly(methylmethacrylate) blend films presenting with a spherical-like microstructure at low sample concentration, whereas at relatively high concentrations the depolarization factor shifted to values closer to 1. This indicated the formation of flat microstructures due to aggregation of the polyaniline particles [8]. 

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