Orientation of bacteriorhodopsin in non-aqueous polymer membrane

Summary Electric field orientation of bacteriorhodopsin (BRp) in the form of purple membrane (PM) in synthetic polymer membranes made from poly(hydroxy-methyl methacrylate) or photo-crosslinkable propyleneoxide-based prepolymer was achieved by combining once-desalted and liophilized PM sample and ethylene glycol as a dilutant, which was detected by an increase in photoelectric current or membrane potential, respectively.We gratefully acknowledge the kind advice and helpful discussion of Professor Fumio Tokunaga and Dr. Tatsuro Iwasa (Tohoku University).     

Possible role of dentin matrix in region-specific deposition of cellular and acellular extrinsic fibre cementum

The mechanism whereby a region-specific deposition of the two types of cementum (cellular cementum and acellular extrinsic fibre cementum) is regulated on the growing root surface was tested using bisphosphonate-affected teeth of young rats and guinea pigs. The animals were injected subcutaneously with 8 or 10 mg P x kg body weight(-1) x day(-1) of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) for 1 or 2 weeks. In rat molars, HEBP prevented mineralization of newly formed root dentin matrix and totally inhibited de novo deposition of acellular extrinsic fibre cementum. Instead, thick cellular cementum was induced on the non-mineralized root dentin surface, irrespective of the position of the root. In both animals, cellular cementum was also induced on the non-mineralized surface of root analogue dentin in HEBP-affected incisors, where only acellular extrinsic fibre cementum is deposited under normal conditions. In normal rat molars, dentin sialoprotein (DSP) was concentrated along the dentin-cellular cementum border, but not that of dentin and acellular extrinsic fibre cementum. In HEBP-affected rat incisors, DSP was shown to penetrate through the non-mineralized dentin into the surrounding tissues, but not through the mineralized portions. These data suggest that, at the site of cellular cementum formation, putative inducing factors for cellular cementum might diffuse into the periodontal space through the newly deposited mantle dentin matrix before it is mineralized. At earlier stages of root formation, mantle dentin might mineralize more promptly not to allow such diffusion. The timing of mineralization of mantle dentin matrix might be the key determinant of the types of the cementum deposited on the growing root surface.     

Lipid synthesis and acyl-CoA synthetase in developing rice seeds

Developing rice seeds rapidly accumulated storage lipids between 5 and 12 d after flowering. The contents of palmitic, oleic, and linoleic acids increased throughout seed development, while the alpha-linolenic acid content remained low. The activity of acyl-CoA synthetase varied coincidentally during the period of lipid accumulation, and rice seeds had a sufficient capacity to supply acyl-CoA substrates for TAG synthesis. Acyl-CoA synthetase showed a broad specificity for native FA of rice seeds except for stearic acid, and pi electrons of a delta9-delta11 double bond in the C16-C18 acyl chains were required for its maximal activity.     

Solitons in the one-dimensional antiferromagnet in a magnetic field

The one-dimensional classical planar antiferromagnet in an applied magnetic field in the plane of the planar spin is analyzed theoretically. Solving the transfer matrix equation, we calculate the transverse and the longitudinal spin correlation lengths. The dynamical structure factors are also determined. The transverse spin fluctuations are dominated by the multisoliton term, while the longitudinal spin fluctuations are dominated by a single magnon term.This work was supported in part by the National Science Foundation under grant DMR 76-21032.Guggenheim Fellow 1979-80. On sabbatical leave from Department of Physics, University of Southern California, Los Angeles California.Laboratoire associé au CNRS.     

Feasibility study of nitride fuel core and recycle system toward self-consistent nuclear energy system

A concept of nitride core and recycling system in relation to SCNES⁽¹⁾ has been investigated and it has been found that the safety of intact core is enhanced by zero burnup reactivity and negative feedback at ULOF (Unprotected Loss of Flow) and ULOHS (Unprotected Loss of Heat Sink). The self-actuating modules are examined so as to eliminate recriticality of degraded core. The nitride core can employ transuranics-added fuels and burn long life radioactive fission products after isotope-separation of FPs. The enrichment of ¹⁵N and the laser isotope separation seem to need about 2.4% of produced electric energy in the preliminary evaluation.     

Field-induced surface texture in 3He-A in the presence of superflow

The effect of superflow on the magnetic field-induced surface texture in ³He-A is studied theoretically. We find that in the presence of small superflow the surface texture becomes nonplanar. The NMR satellite frequencies associated with the surface texture are obtained.Supported by National Science Foundation grant No. DMR76-21032.     

Paraconductivity in type-II superconductors

The additional conductivity due to the fluctuation of the order parameter in dirty type-II superconductors is reconsidered. It is shown that in a magnetic fieldH slightly above the upper critical field the electric conductivity is strongly anisotropic depending on the relative direction of the magnetic field and the electric current. In the parallel case (i.e.,H J) the conductivity diverges like(H–H _c2)^–3/2, while in the perpendicular case (H J) it diverges like(H–H _c2)^–1/2.     

Thermoelectric power above the superconducting transition

The thermoelectric power in the fluctuation region above the superconducting transition temperatureT _c is studied theoretically. Use is made of the time-dependent Ginzburg-Landau (TDGL) equation due to Ebisawa and Fukuyama, which includes the correction term of the order ofT/μ as well, whereT is the temperature and μ is the chemical potential. It is shown that the thermoelectric power tends to zero as (T?T _c ) ln [T/(T?T _c )] and as (T?T _c ) as the temperature approaches the transition temperatureT _c for the two-dimensional and the one-dimensional systems, respectively.     

Approximate Calculation of Block Replacement with Weibull Failure Times

A block replacement policy with Weibull failure times is considered. It is troublesome to compute an optimum planned replacement time numerically. An asymptotic calculation is given in terms of pdf and the failure rate. A numerical example shows that under some conditions the formulas help approximate an optimum time.