A. Elliott and E. J. Ambrose, Discuss. Faraday Soc., 1950, 9, 246 DOI: 10.1039/DF9500900246

An x-ray collimating system suitable for observing diffraction patterns of fibres, powders and films with radiation 1.54 Å wavelength is described. The uses a gold-coated toroidal mirror enables to be recorded photographically in much less time than required conventional systems giving equal resolution. A substantial degree monochromatization obtained, the current spacings shorter about 35 may observed. camera which film form cone also Typical exposure times Hilger Watts generator 3 mA at 45...

Methods of producing oriented films synthetic polypeptides when prepared from various solvents are described. The polarized infra-red spectra a number these have been measured. It is shown, in agreement with earlier work, that the can exist folded ( α ) and an extended β configuration. In form N—H C═O stretching modes polypeptide chain show parallel dichroism while deformation mode shows perpendicular dichroism. conditions reversed. has characteristic frequencies about 1660 1560 cm. -1 ,...

An experimental procedure is described for measuring dichroism in the infra-red spectrum of oriented materials. Oriented films polythene, polyvinyl alcohol, chloride, acetate, and Nylon have been examined region 3600–700 cm−1, species (parallel or perpendicular) many bands has identified. The bearing these results on current ideas concerning structure polymers discussed. A general result that frequencies involving motion hydrogen atoms show rather low dichroism. On other hand, very high...

The spectra of silk suture, porcupine quill, elephant hair, swan gelatine and rat-tail tendon have been observed with polarized infra-red radiation. first four materials give which show that they contain both extended ( β ) folded α peptide chains. A band at about 4600 cm. -1 is assigned to a C = O combination frequency, whose dichroism indicates the direction transition moment for deformation mode. Gelatine collagen similar spectra, are different from either or proteins polypeptides. method...

A number of polymers and copolymers containing β -benzyl-L-aspartate has been prepared their optical rotatory dispersion in a variety solvents measured. The results these measurements together with studies infra-red spectra, X-ray diffraction patterns, deuteration rates molecular models lead to the following conclusions. (i) α -helical form poly- is considerably less stable relative solvated randomly coiled than that γ -benzyl-L-glutamate. (ii) left-handed -helix more right-handed one. (iii)...

A transmission polarizer for the near infra-red is described, which small and compact can be mounted on a spectrometer without alteration of existing optical system. It employs pile self-supporting selenium films, each approximately 4 microns thick. The advantages such possesses over other forms are pointed out, factors affecting design briefly discussed. method preparing Se films described in detail. percentage polarization, measured by crossing two similar piles, better than 94 percent...

The infra-red absorption bands associated with the peptide groups in globular proteins, folded synthetic polypeptides and α -fibrous proteins are very similar. spectra of denatured extended chain β-fibrous also Denatured fibrous insulin is shown by polarized-beam techniques to consist β chains lying perpendicular fibril axis, a layer structure involving inter-chain hydrogen bonded grids. Rhombohedral crystals show dichroism consistent an arrangement packed trigonal axis. A mechanism explain...

The balance between the concentrations of free ionized Ca2+ and bicarbonate in pancreatic juice is critical importance preventing formation calcium carbonate stones. How pancreas regulates ionic composition level saturation an alkaline environment such as not known. Because tight cause-effect relationship concentration lithogenicity, because hypercalcemia proposed etiologic factor for several diseases, we have investigated whether tissues express a Ca2+-sensing receptor (CaR) similar to that...

The infra-red spectrum of several synthetic polypeptides with small side chains (polymers glycine and alanine) have been examined in the region 800 to 1700 cm -1 . observations include measurements polarized radiation on α (folded) β (extended) forms poly-L-alanine; deductions from these results are compared those derived X-ray similar materials. Some deuterated poly-DL-alanine also made. new enable a partial classification bands little explored 1500 be silk gut water-soluble They emphasize...

The optical rotations of a number synthetic polypeptides have been measured in variety solvents. For each polypeptide species, copolymers different D:L compositions examined. Several distinct types behaviour found, which may readily be interpreted terms the relative stability left-handed helices, right-handed and random coils. In solvents that are not too polar (even for quite considerable departures from enantiomorph) predominantly L polymers exist entirely as helices. rotation helical form...

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The near infra-red region may be used to obtain spectra with polarized radiation of natural and synthetic fibres. This has considerable experimental advantages the poly-L-alanine, polyglycine, wool, silks commercial regenerated protein fibres are shown discussed. Besides supplementing other types observation, information obtained on orientation molecular configuration not always given by methods.

The use of polarized infra-red radiation in examining the structure and orientation high polymers has been investigated quantitatively. It is shown that spectroscopy can furnish evidence for double rolled sheets nylon 66, polyvinyl alcohol (with less certainty) polythene. In case formate, acetate, chloride polyvinylidene such could not be detected. Evidence given to show N -H bond bent by hydrogen bonding forces, angle between this plane skeleton being thereby reduced from 39° (the valency...