Showing papers on "Resolution (electron density) published in 1968"
784 citations
TL;DR: The phase angles of 8,000 reflexions were determined by the method of isomorphous replacement, using crystals of native haemoglobin and of three heavy atom derivatives.
Abstract: The phase angles of 8,000 reflexions were determined by the method of isomorphous replacement, using crystals of native haemoglobin and of three heavy atom derivatives. The electron density maps show the positions of nearly all the amino-acid residues and some details of the haem groups. Next week the second part of this article—the atomic model—will appear.
145 citations
TL;DR: It is concluded that the four iron atoms of Chromatium high-potential iron protein reside in a single unresolved cluster.
77 citations
55 citations
TL;DR: The electron spin resonance spectrum of +H3NĊHCOO− in single crystals of glycine γ irradiated at room temperature has been re‐examined at X band and evaluated by resolution‐enhancement technique, and the structure of the radical is confirmed.
Abstract: The electron spin resonance spectrum of +H3NĊHCOO− in single crystals of glycine γ irradiated at room temperature has been re‐examined at X band and evaluated by resolution‐enhancement technique. The resolution enhancement is obtained by reducing the linewidth by a factor of maximum 0.55 at the expense of the signal‐to‐noise ratio. The calculations, which require a high‐speed digital computer, consist of three steps: (1) transformation of the experimental spectrum to a complex Fourier plane, (2) multiplication of this Fourier spectrum with a suitable linewidth‐reduction function, and (3) inverse transformation back to the real plane. From the obtained constants, the hyperfine coupling tensors have been calculated, including contributions from second‐order effects (ΔMI = ± 1). One of the principal values of one of the tensors was appreciably affected by these second‐order effects. The results fully confirm the structure of the radical.
51 citations
47 citations
01 Jan 1968
36 citations
TL;DR: In this article, the relationship of the resolution function of a conventional two-crystal diffractometer for elastic scattering to that of a three-dimensional (3D) diffraction model is discussed.
Abstract: The relationship of the resolution function of a conventional two-crystal diffractometer for elastic scattering to the resolution function of a three-crystal diffractometer is discussed. An analytic expression is derived for its form assuming Gaussian mosaic and collimation angles and the application of this to the measurement of elastic scattering is considered.
35 citations
TL;DR: In this paper, the parallel band ν2 of 10BF3 has been remeasured with a resolution of about 0.03 cm−1 and new values of the rotational constants have been determined.
Abstract: The parallel band ν2 of 10BF3 has been remeasured with a resolution of about 0.03 cm−1 and new values of the rotational constants have been determined. The values of B0 = 0.34474 ± 0.0005 (10BF3) and B0 = 0.34505 ± 0.0005 cm−1 (11BF3) are consistent with the geometry obtained in the electron‐diffraction experiments of Kuchitsu and Konaka, but differ appreciably from the values previously reported by Nielsen. From our results we obtain r0 = 1.3096 ± 0.001 A (10BF3), re = 1.3090 ± 0.001 A (11BF3), and r0 = 1.3072 ± 0.002 A (10BF3). From the analysis of the hot bands we have determined values of (B′ − B″) for ν4 and some of the anharmonic constants xss′.
31 citations
TL;DR: In this article, the hyperfine spectrum of the J = O → 1 rotational transition of the H127I molecule has been investigated with the resolution submillimeter wave beam-spectrometer.
29 citations
TL;DR: High resolution electron micrographs of arginine decarboxylase with different sizes of the phase image granularity are demonstrated, demonstrating the maximum sharpness and the best resolution.
TL;DR: In this paper, the experimental determination of the resolution function of a two-crystal neutron diffractometer is discussed and the form of the Bragg reflection profiles observed for a perfect crystal using conventional scanning modes is considered in detail.
Abstract: The experimental determination of the resolution function of a two-crystal neutron diffractometer is discussed. The form of the Bragg reflection profiles observed for a perfect crystal using conventional scanning modes is considered in detail and their application to the measurement of diffuse elastic scattering is discussed.
Journal Article•
TL;DR: It is demonstrated that particles originating in 55 Fe foci are sufficiently localized to permit high-resolution radioautographic analysis of red cells viewed in thin sections.
Abstract: The radioisotope 59Fe is used extensively for biochemical investigations of hemoglobin synthesis in maturing red cells. Its usefulness for radioautography is more limited, largely because high-energy beta particles emitted by 5Fe exhibit a long path and, therefore, produce scattered patterns of reduced silver grains in photographic emulsion overlying labeled cells. Another isotope, however, low-energy emitting 5 Fe, would appear to be more favorable for radioautographic work on the basis of theoretical considerations (Forberg et al., 1964) and early results from light microscopic radioautography (Fowler et al., 1966). The former paper indicates that 5 SFe disintegrations produce three physical classes of emissions which include rntgen radiation, mainly X-rays, with an energy of 6 kev (0.19/d ) and Auger electrons of either 5-6.5 kev (0.5/d) or 0.5-0.6 kev (1.2/d). The present paper demonstrates that particles originating in 55 Fe foci are sufficiently localized to permit high-resolution radioautographic analysis of red cells viewed in thin sections. This localization is shown first with the use of remnants of hemolyzed reticulocytes as structurally defined sources of 55Fe label and, in a second aspect of the
Patent•
12 Mar 1968
TL;DR: In this article, the authors proposed a method for making image-plane plates of glass stained on one surface, in accordance with improved resolution and/or the advantage associated with having a planar plate surface.
Abstract: THE INVENTION COMPRISES IMPROVEMENTS IN MAKING IMAGE-PLANE PLATES OF GLASS STAINED ON ONE SURFACE THEREOF, IN ACCORDANCE WITH WHICH IMPROVED RESOLUTION AND/OR THE ADVANTAGES ASSOCIATED WITH HAVING A PLANAR PLATE SURFACE ARE OBTAINED BY USING THE SCREENING ACTION OF TIN OXIDE, WHICH PREVENTS METAL STAINING OF THE GLASS.
TL;DR: A three-dimensional Fourier synthesis at an axial resolution of 75 angstroms of optical diffraction data from electron micrographs of stained sections of chromatoid bodies reveals the position of the large and small ribosomal subunits within these crystals of ribosomes.
Abstract: A three-dimensional Fourier synthesis at an axial resolution of 75 angstroms of optical diffraction data from electron micrographs of stained sections of chromatoid bodies reveals the position of the large and small ribosomal subunits within these crystals of ribosomes.
TL;DR: In this article, the authors report improvements in resolution and signal-to-noise ratio for total internal reflection hologram reconstructions, and describe the conditions employed to produce these results.
Abstract: This Letter reports improvements in resolution and signal‐to‐noise ratio for total internal reflection hologram reconstructions. It outlines the conditions employed to produce these results and indicates some of the relevant properties.
16 Feb 1968
TL;DR: In this article, a prediction operator is used to extend the length of the spatial correlation functions in order to obtain higher resolution of the resulting spectra in wavenumber space, which is most useful in the case of small arrays, where the spatio-temporal correlation functions are too short to give adequate resolution for the ordinary frequency-wavenumber spectra.
Abstract: : The method of high-resolution spectral analysis has been applied to one- and two-dimensional wavenumber spectra. In this method a prediction operator is used to extend the length of the spatial correlation functions in order to obtain higher resolution of the resulting spectra in wavenumber space. It is most useful in the case of small arrays, where the spatial correlation functions are too short to give adequate resolution for the ordinary frequency- wavenumber spectra. A theoretical description of the method, its procedures, and its relation to ordinary wavenumber spectra is given. In particular, an analytical expression is derived for the resolution and the response of the process in the case of an input plane wave, where the high-resolution method is averaged over all reference sensors. Disadvantages of the high-resolution method are discussed, in particular an unrecoverable distortion of the true amplitude spectrum.
TL;DR: In this paper, the real image formed by a hologram has been investigated experimentally with a view to overcoming the disadvantages of the present contact-print method of manufacturing microcircuits.
Abstract: The resolution of the real image formed by a hologram has been investigated experimentally with a view to overcoming the disadvantages of the present contact-print method of manufacturing microcircuits. A resolution of 4μm over an area of 2.5 cm diameter has been obtained so far.
TL;DR: In this paper, the application of the resolution function of a two-crystal neutron diffractometer to the measurement of Bragg peaks is discussed in detail and experimental measurements of peak widths are compared with theoretical predictions.
Abstract: The application of the resolution function of a two-crystal neutron diffractometer to the measurement of Bragg peaks is discussed in detail and experimental measurements of peak widths are compared with theoretical predictions.
TL;DR: The most attractive advantages of the scanning electron microscopy are (a) direct examination, (b) no sample preparation, (c) accommodation of large size samples, (d) satisfactory resolution, range of magnification from 20X to 100,000X, very large depth of focus, and (e) capability to examine a specimen in a number of orientations as mentioned in this paper.
Abstract: Based on the above considerations, the scanning electron microscope has unique capabilities for the study of fracture surfaces and should extensively replace the replication fractography currently used with the TEM. The most attractive advantages of the SEM are (a) direct examination, (b) no sample preparation, (c) accommodation of large size samples, (d) satisfactory resolution, (e) range of magnification from 20X to 100,000X, (f) very large depth of focus, and (g) capability to examine a specimen in a number of orientations. Despite the absence of diffraction in the SEM (which appears to be the only disadvantage of this process, at present), it is obvious that, for fractography purposes, scanning electron microscopy has an equally important or a greater role to play than TEM fractography in the coming years.