Materials Literature
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The elimination and retention of a new, fully synthetic plasma prosthesis of Czechoslovak origin under the working name of Duxon (poly[N-(2-hydroxypropyl)methacrylamide]) was investigated in experiments on rabbits by using a 14C-labeled polymer. Results published earlier on elimination have been confirmed and extended…
Polymerization of collagen in vitro has been studied with the electron microscope at early time points of fibril assembly. We have found morphologically distinct stages of aggregation, which we suggest represent successive steps in fibril formation. Linear growth of the fibril appears to occur by the tandem addition o…
1. A fragment of human subcomponent C1q was prepared by limited proteolysis with pepsin at 37 degrees C for 20 h, and at pH4.4, followed by gel filtration on Sephadex G-200. This fragment was shown to contain all the collagen-like features known to be present in the intact molecule [Reid (1976) Biochem. J. 155, 5-17].…
The bacterial phosphotransferase system (PTS) catalyzes the transfer of the phosphoryl group from phosphoenolpyruvate to its sugar substrates, PTS sugars, concomitant with the translocation of these sugars across the bacterial membrane. The phosphorylation of a given sugar requires four proteins, two general proteins,…
The stress corrosion cracking (SCC) of mild steel in saturated ammonia vapor was studied by slow straining of a hollow specimen, which could be heated or cooled in relation to the temperature of the liquid. SCC was effectively prevented if the specimen was heated 1 to 2 C above the temperature of the liquid, but SCC d…
Single crystal specimens of niobium with axes near 〈111〉 and 〈011〉 have been deformed at 295 K in either tension or compression in order to investigate the formation of kink bands in body centred cubic structures. Slip occurred in the 〈111〉 direction on both {10} and {11} planes and the relative values of the critical…
Abstract Glass formation and crystallization were investigated in two types of three-component systems, M2O–Al2O3–P2O5 (M=Li, Na, and K) and MO–Al2O3–P2O5 (M=Mg, Ca, and Ba). In the Li2O–Al2O3–P2O5 and MO–Al2O3–P2O5 systems, wide regions of glass formation were found in compositions containing more than 50 mol% of P2O…
Abstract A theory is presented for the formulation of flux equations which describe the transport of water, salt, and electric charge through clays. This theory is based on thermodynamic principles. Model considerations lead to analytical expressions for the transport coefficients. These model calculations are based o…
How can we develop a unified way of dealing with structures covering the range from diamond, naphthalene and iron to living objects? Dr Mackay suggests that ‘cellular automata’, which show aspects of reproduction, growth and evolution, may provide the answer
The hydrogen induced cracking (HIC) of as-rolled steels has been investigated. The specimens were immersed into the synthetic sea water saturated with H2S. Since the cracks initiated at the elongated MnS particles, the HIC susceptibility decreased with decreasing sulfur content. It was, however, often observed that th…
Abstract The mechanism of membrane formation by interfacial polycondensation was studied. For the time‐conversion curves the equation was derived ( x′ = reduced membrane thickness). The membrane morphology was investigated by x‐ray scattering and electron microscopy. It was found that the polymer chains are mainly ori…
The hexagonal and cubic phases of the intermetallic compound Fe 3 Ge have been investigated with the Mossbauer effect technique and magnetization measurements. In both phases the material is ferromagnetic with T c =640K and mu Fe =2.0 mu B (hexagonal), and T c =740K and mu Fe =2.2 mu B (cubic). In the hexagonal phase…
The stability fields of michenerite and merenskyite have been defined above about 450 degrees C. Michenerite forms an extensive but narrow solid-solution field by substitution between Bi and Te from Pd (sub 0.99) Bi (sub 0.79) Te (sub 1.22) to Pd (sub 0.95) Bi (sub 1.11) Te (sub 0.94) ; Pd ranges from 31.5 to 33.2 ato…
peer reviewed
The properties of permanent magnets based on RCo5compounds arise from their strong uniaxial anisotropy. The anisotropy field at 4.2 K in YCo5is about 200 kOe. A polarized neutron study of YCo5revealed a very large orbital contribution to the magnetic moment on the CoI(2c) site, which indicates that the major part of t…
A qualitative and quantitative investigation was undertaken to study the susceptibility of unicellular eucaryotic organisms (yeasts) to metallic cations generated by low levels of direct current. Results were characteristic of effects obtained previously using clinical and standard bacteria test organisms. The present…
A critical account has been presented of the recent investigation on the chemical modification of lignocellulosic sisal fibers. The molecular structure of the paracrystalline cellulose, which forms the major constituent of the fiber, was studied by x-ray diffraction technique. Scanning electron microscope examination…
Material and mode dispersion in fibers made from glasses in the system GeO 2 ‐B 2 O, 3 ‐SiO 2 have been calculated using refractive index dispersion results for these glasses. Refractive indices were measured on bulk glass specimens using the minimum deviation method at wavelengths from 0.4358 to 1.0830 μm. The result…
Open-circuit dark surface-potential decay characteristics have been measured in positively corona-charged films of solution-cast low-density polyethylene. For initial fields of about 5×105 V/cm, the surface potential V (t) decays linearly for a period of time, after which it is curvilinear. As a result, the time deriv…
Abstract Pit nucleation and repassivation on iron and nickel has been examined by potentiostatic transient measurements. Very short times for the nucleation of corrosion pits of some ms to some 100 ms for prepassivated specimens have been observed. Addition of picrate to the electrolyte can stop pit nucleation for wel…