Two-dimensional wide line separation

A useful method to correlate IH and 13C signals is wide-line separation In a two-dimensional (2D) spectrum high-resolution 13C CP MAS spectra are taken in one dimension, and correlated to the IH wide-line spectra of the protons attached to each resolvable carbon atom. This enables the correlation between the IH mobility, as detected by the linewidth, and the 13C structure viewed by the chemical shifts. 

Fig. 15. The pulse sequence for the 13C 2H correlation experiment.38 This two-dimensional experiment, conducted under magic-angle spinning, separates 2H line-shapes according to the 13C isotropic chemical shift of nearby l3C spins, i.e. the bonded l3C in practice. The narrow black pulses are 90° pulses wide ones are 180° pulses. The 2H pulses are placed symmetrically within the rotor period.

Use of Complex Standards for Cell Proteins and Two-Dimensional Electrophoresis. One of the more widely-used cell lines chosen as a reference standard is the lymphoblastoid cell line GM607, derived from a normal individual and available from the Human Genetic Mutant Cell Depository, Camden, NJ 08103. This cell line may be grown in defined media, labeled with a radioactive tracer, and reproducibly separated in a 2-DE system. Heat shock proteins may readily be isolated and visualized from this cell line, as shown by Anderson et al. (42). For serum, a reference preparation for serum proteins is available as a certified reference material prepared and assayed by the College of American Pathologists (CAP) and by the U. S. Centers for Disease Control. A widely available human serum standard is that provided by the National Bureau of Standards as SRM 909. If sufficient interest from the user community is evident, a full electrophoretic characterization of this material can be included in the documentation. If the amount of selected standard proteins loaded on a gel is known, "relative" quantification of similar proteins could be obtained. In addition, the National Bureau of Standards could serve as an impartial evaluator of potential national standards (e.g. molecular weight standards, "tie-point" proteins, and Isoelectric point standards) to assess suitability and stability. 

Variation dL/ dx with x for the first order phase transition model and the equilibrium soap film configurations within the four-pin model, with the illustration of the corresponding energies with respect the configurations a and b. (a) Pair of pins are close to each other (b) pairs of pins are widely separated. Note that the lines in reality are two-dimensional, but their sizes do not change in the other dimension. 

A separate mention is merited for a special molded hardboard product. These are made by a process in which either a fiber mat or hardboard panel is placed between two shaped platens and press-molded to a three-dimensional configuration. The most common resulting shape is a doorskin which resembles a wood panel door. The doorskins are bonded to wood frames to make an excellent, attractive, and relatively inexpensive door. This ftber/panel mol ding process is also used to make a wide variety of molded interior linings used in automobile manufacture. 

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