Microscopy, temperature control

An unusually extensive battery of experimental techniques was brought to bear on these comparisons of enantiomers with their racemic mixtures and of diastereomers with each other. A very sensitive Langmuir trough was constructed for the project, with temperature control from 15 to 40°C. In addition to the familiar force/area isotherms, which were used to compare all systems, measurements of surface potentials, surface shear viscosities, and dynamic suface tensions (for hysteresis only) were made on several systems with specially designed apparatus. Several microscopic techniques, epi-fluorescence optical microscopy, scanning tunneling microscopy, and electron microscopy, were applied to films of stearoylserine methyl ester, the most extensively investigated surfactant. 

Hot stage microscopy was performed using a Mettler FP52 temperature controller at a rate of 3°/minute. Melting began at 268.2°, and by 271.4° all crystals were melted. The yellow melt slowly turned orange-brown. Cooling showed no recrystallization at ambient temperature. 

Yamanaka, K., Nagata, Y., and Koda, T. (1989). Low temperature acoustic microscopy with continuous temperature control. Ultrasonics. Int. 89, 744-9. [204]... 

Crystal reaction study mechanistic tools, 296 computer simulation, 297 electronic spectroscopy, 298 electron microscopy, 298 electron paramagnetic resonance (EPR), 299 nuclear magnetic resonance (NMR), 298 Raman spectroscopy, 299 Crystal reaction study techniques crystal mounting, 308 decomposition limiting, 309 polarized IR spectroscopy, 309 temperature control, 308 Cycloreversions, adiabatic photochemical involving anthracenes, 203 excited state properties of lepidopterenes, 206... 

Hammerschmidt, J.A. Gladfelter, W.L. Haugstad, G. Probing polymer viscoelastic relaxations with temperature-controlled friction force microscopy. Macromolecules 1999, 32, 3360-3367. 

Careful temperature control is necessary so that ice crystals neither melt nor grow while they are imaged. This can be achieved by performing the sample preparation and microscopy inside temperature-controlled chambers or by carrying out the whole experiment in a cold room. The temperature of the cold chamber is set to the required imaging temperature, for example — 5 °C for ice cream that has just come out of the factory freezer, or —18 °C for ice cream that has been hardened and stored. A small sample of ice cream is smeared onto... 

Let us now look at the different locations for spontaneous encapsulation of solutes of different chemical composition. First of all, it goes without saying that encapsulation experiments should be carried out under weU-defined conditions. Often vesicles, after their preparation, and subsequently after binding of the solubilizate, need time to arrive at their most stable configurations (size, tail ordering) and adeqnate attention should be given to this issue. This process may sometimes take days at room temperature. Also the method used for their preparation may exert a definite effect on the vesicular properties. Thus, for a honest comparison of encapsnlation abilities, it is recommended that the vesicles are prepared under exactly the same conditions and that their properties are checked by a proper physical technique, such as cryo-electron microscopy. Also temperature control needs attention since the gel and liqnid-crystaUine phase exhibit different binding efficiencies of solutes. 

Fig. 10.16 Left optical microscopy imageof the electrode array with overlay of the spreading of 1,5, and 10 pL droplets added after grinding of the array. Right humidity and temperature control during droplet experiments using saturated salt solutions of KCl and MgCl2 [64].

For microinjection and subsequent analysis (e.g. by time-lapse microscopy), cells are plated on 35 mm dishes with coverglass bottoms (MatTek Corp., Ashford, MA, USA), that allow for the use of high numerical aperture, short distance objectives. During injection and time-lapse microscopy, cells are incubated in tissue culture media preferably without phenol red and only low concentrations of serum (1%) to keep background fluorescence from the culture medium to a minimum. To keep the pH stable, carbonate-free culture medium (Gibco) buffered with 20 mM Hepes pH 7.4 is used. Temperature is kept at 37 °C, for example by enclosing the entire microscope and microinjection manipulators in a temperature controlled Perspex box. 

Abstract Surface-induced ordering of 4-n-octyl-4 -cyanobiphenyl (8CB) near the isotropic-nematic phase transition was investigated using temperature-controlled atomic force microscopy (AIM). The glass surfaces in contact with liquid crystal were modified by an adsorbed silane surfactant, a deposited 8CB mono-layer, or a deposited 8CB trilayer. 

Molecular Relaxations in Polymer Films Studied by Temperature-Controlled Friction-Force Microscopy... 

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