High-resolution imaging at the cellular and subcellular levels in flattened whole mounts of early zebrafish embryos

We describe a rapid and sensitive method for high-resolution imaging at the cellular and subcellular levels in the whole-mount zebrafish embryo. The procedure involves fixing and staining the embryo, followed by deyolking and flattening it under a cover slip, to produce a planar mount that is 20 to 100 microns thick. Such a flattened whole mount allows imaging with a spatial resolution of approximately 500 nm in the x-y plane and does not require the use of embedding, sectioning, confocal microscopy, or computational deblurring procedures. We can resolve all individual nuclei and chromosome sets in the embryo, up to the late gastrula stage (10,000 cell stage). In addition, older embryos (through the segmentation stage) can also be examined, with the preservation of significant morphological detail. Because of its ability to resolve subcellular detail, the flattened whole-mount method can provide significant biological information beyond what can be obtained from conventional (three-dimensional) whole mounts. We have used the flattened whole-mount method to study subcellular events related to progression through the cell cycle or to apoptosis, in cells of the early zebrafish embryo. A specific DNA-binding dye (Hoechst 33258) or an antibody against a chromosomal protein (histone H1) was used to stain the nuclei of individual cells in the embryo. This allowed us to determine the spatial positions of all the individual cells, and also their stages in the cell cycle. A terminal transferase (TUNEL) assay was used to detect apoptotic cells. This combination of specific stains allowed us to study the behaviors of groups of cells in situ, within the developing zebrafish embryo.     

Experimental study on the effects of tension-reduced early mobilization on extensor tendon healing

Numerous clinical and experimental studies have been reported on early postoperative mobilization after flexor tendon repair. However, there have been only a few experimental studies reported on extensor tendon repair. In 1989, Ishiguro reported the usefulness of tension-reduced early mobilization in clinical cases of extensor tendon ruptures. The purpose of this experimental study was to examine the in vivo effect of tension-reduced early mobilization on extensor tendon healing in chicken. An experiment was performed on the extensor tendons of 218 chickens in an attempt to examine the effects of tension-reduced early mobilization on tendon healing and adhesion. The extensor tendon of the fourth toe was cut and the distal stump of the tendon was transferred to the extensor tendon of the third toe. Postoperatively two protocols were employed. In the immobilization group, a cast was applied for three weeks. In the early-mobilization group, immediate active motion of the digits was allowed. A tension-reduced position was maintained by taping the fourth toe to the dorsum of the third. The findings from the early mobilization group and from the immobilization group were as follows: 1. Macroscopically, sutures at the repair site of the early-mobilized tendon were not evident after three weeks because of fibrous connective tissue growth. Despite this abundant connective tissue, tendon gliding was observed to be smooth. Between the suture site and the gliding floor, loose connective tissue, similar to normal paratenon, was observed. Histology confirmed this observation. 2. The tensile strength required to extend the MP joint was significantly lower for the early-mobilization group than for the immobilization group, suggesting minimal adhesion between the sutured tendon and the gliding floor in the early-mobilization group. 3. No significant difference in tensile strength among the various tendon repair techniques employed was observed at the suture site.     

Temperature inhomogeneity in the glass mixing chamber of a (3)He/(4)He dilution refrigerator

The temperature inhomogeneity in the glass mixing chamber of a (3)He/(4)He dilution refrigerator has been studied. The inhomogeneity is reduced to 10 mK by inserting a cylindrical spacer in the mixing chamber.     

Optimum operation of DFB lasers under chirped pulse transmission

Theoretical calculations together with measurements of the chirping characteristics of DFB lasers have revealed the existence of optimum bias condition for longer transmission distance. Ultimate transmission distances in connection with fibre loss and dispersion are estimated for 1.3 and 1.5 ?m transmission on the basis of experimental device characteristics.     

Research of core characteristics of the Package-Reactor

A new small reactor concept called the Package-Reactor has been jointly developed by Hitachi, Ltd. and Mitsubishi Heavy Industries, Ltd. The reactor technology was based on that of conventional LWRs. The reactor core consists of 12 cassettes containing fuel rods with a similar design to that of PWR fuel rods. Cassettes are placed in air at atmospheric pressure. Tube-type control clusters placed outside the pressure boundary are used as the core shutdown system. Natural circulation with two-phase flow is employed for the core cooling system and no re-circulation pumps are required. With these concepts the Package-Reactor eliminates any active components that operate in high pressure regions of the reactor and its capital costs can be reduced. The feasibility of reactivity control by using moderator void feedback and burnable poisons was studied to reduce operational and maintenance costs. It was found that a continuous operation of more than 5 years without any operations to control reactivity would be feasible with a UO₂ fuel enrichment of 5.0 wt%, which is the upper limit for UO₂ fuel enrichment under the current regulations in Japan. In addition, we researched the core reflectors' characteristics of the Package-Reactor.     

Theoretical Description of a Two-dimensional Compaction Process of Cylinders

Two possible two-dimensional packing cases, one with slippery cylinders and the other with adhesive cylinders, were analyzed both experimentally and theoretically. In both cases, cylinders 10 mm in diameter and 16 mm in height were arranged inside a compaction apparatus in a random manner. The slippery cylinders were compacted to a maximum possible random closed array with little applied pressure, and virtually no further rearrangement was achieved, even by applying large additional pressure on the assembly. Compaction of the adhesive cylinders, on the other hand, occurred more gradually with applied pressure. Compaction of the cylinders resembled three-dimensional powder compaction.     

Interferon treatment of chronic hepatitis C--assessment of predictive factors to the effect of interferon treatment using multivariate analysis with the logistic regression model

We treated 156 chronic hepatitis C patients with alpha-interferon (IFN) and assessed the response rate and the predictive factors to the effect of IFN treatment. Complete response (CR) rate was 39.1%, and CR with serum HCV-RNA disappearance rate was 29%. CR to IFN treatment was dependent on HCV serotype and serum HCV-RNA. Patients of serotype II and low serum HCV-RNA were effective to IFN treatment.     

Sorption of flavour compounds in aqueous solution into polyethylene film

Sorption of flavour compounds by the polyethylene (PE) liner of laminated pouches (PET/Al/PE) containing a flavour solution has been studied. The solution contained 43 volatile compounds (each 2 μl litre^?1) in sugar ester solution (3 g litre^?1). The distribution ratios of the flavour compounds for sorption into various PE liners increased with carbon chain length of the flavour compounds from 0.01 to 0.1 for alcohols, from 0.03 to 1.23 for aldehydes, from 0.02 to 5.77 for aliphatic esters and from 0.11 to 11.6 for benzoates. In each series (all straight-chain compounds) the distribution ratios increased about threefold for each methylene group, but in the compounds composed of 11 or more carbon atoms the increment was less or negative. The distribution ratio for a given PE film was proportional to the film thickness. The distribution ratios increased with decreasing crystallinity of the PE film and the results for the films of different crystallinities suggested the existence of an impermeable boundary region surrounding the crystalline material amounting to about 20% of its volume.     

0.66 ?m room-temperature operation of InGaAlP DH laser diodes grown by MBE

Room-temperature pulsed operation of In0.49Ga0.31Al0.20P/In0.49Ga0.48Al0.03P/In0.49Ga0.31Al0.20P double heterostructure (DH) laser diodes has been achieved for the first time. The DH layers were grown by molecular beam epitaxy. The lasing wavelength was 0.66 ?m and the threshold current density was 3.2?3.6 × 104 A/cm2 at room temperature.