Neutron dosimetry by the spark counting of tracks in boron-doped film

Thin cellulose nitrate films are doped with a boron compound. After thermal neutron irradiation, the films are etched in an aqueous solution of 10% NaOH, at 50 degrees C, for 1.5 hr, during which the 27 microns thick films are reduced to about 7 microns. The etch-pits caused by 10B(n, alpha)7Li reactions are punched twice at 600 V and then counted at 500 V. The ratio of the spark density to the thermal neutron fluence was found to be 1.0 X 10(-4) for a boron concentration of 1%. After due consideration of background counts, a thermal neutron dose of 0.3 mrem (3 X 10(-6) Sv) can be measured with this system.

Effect of microphase separated structure of polystyrene/polyamine graft copolymer on adhering rat platelets in vitro

Rat platelet adhesion on microphase separated surface of polystyrene/polyamine graft copolymers (SA copolymers) was investigated. Shapes of adhering platelet were very much changeable in response to the mode of microphase separation of SA copolymer surfaces. We assume that the microphase separated structure of SA copolyer may regulate the shape change of platelet through its effect on a redistribution of proteins and/or lipids present at the plasma membrane of platelets.

Effect of hydrophilic and hydrophobic microdomains on mode of interaction between block polymer and blood platelets

ABA-type block copolymers composed of 2-hydroxyethyl methacrylate (HEMA), a hydrophilic monomer, and styrene (St), a hydrophobic monomer, were synthesized by the coupling reaction of telechelic oligomers used as prepolymers. These block copolymers may be represented as microphase-separated structures. It is therefore possible to change the balance between hydrophilicity and hydrophobicity in the level of an assembled order of macromolecules. In response to the relative composition of the copolymers, three typical morphological patterns were observed in electron microscopic photographs: dispersed domains of continuous St chains in the region of HEMA chains, alternate HEMA and St lamellae and finally, dispersed phases of continuous HEMA chains in the region of St chains. The effect of the hydrophilic and hydrophobic microdomains of the copolymers on the mode of interaction between polymers and platelets was studied by the microsphere column method. In the case of homopolymers and random copolymers, a significant degree of platelet adhesion and aggregation was observed. However, the degree of platelet adhesion and deformation was suppressed on the surfaces of the block copolymers containing 0.608 and 0.347 mole fractions of HEMA whose microdomains were hydrophilic-hydrophobic lamellae and isolated hydrophilic islands in hydrophobic areas, respectively. These results show that the microphase-separated structures were antithrombogenic and prevented platelet adhesion and deformation. On the basis of the results obtained, the interaction between platelets and polymer surfaces was described in terms of the effect of hydrophilic and hydrophobic microdomains.

[Radiological study of the accessory skeletal elements in the foot and ankle (author's transl)]

The accessory bones and ossification centers in the foot and ankle were studied in 3,460 radiographs of patients over 7 years of age who consulted our clinic for various reasons from January 1967 to December 1979. The patients comprised of 1,639 males and 1,821 females. The accessory ossicles commonly observed were os tibiale externum, os trigonum, and os peroneum in order of frequency. The os tibiale externum is the commonest accessory bones in the foot and is situated at the point where the tendon of the posterior tibial muscle inserts itself into navicular bone. This ossicle was found to be present in 733 out of 3,460 feet (21.3%). As some authors have pointed out, they are observed somewhat more frequently in females than in males. The os trigonum is an accessory bone which is situated behind the posterior process of the talus. This ossicle was found in 438 feet (12.7%). The os peroneum is a sesamoid in the long peroneal tendon where it bends toward the sole of the foot. This was found in 311 feet (9.0%). Other inconstant skeletal elements were less commonly observed. This os intermetatarseum which is usually located in the first, rarely in the fourth, intermetatarsal space, was found in 91 feet (2.6%). When studied meticulously, this ossicle is found more often than is generally believed. The os subfibulare, situated just under the lateral malleolus, was found in 71 feet (2.1%). The os supranaviculare, situated above the talonavicular joint, was found in 35 feet (1.0%). The os subtibiale, situated just under the medial malleolus, was found in 31 feet (0.9%). The os supratalare, situated above the neck of the talus, was found in 25 feet (0.9%). The calcaneus secundarius, surrounded by calcaneus, talus, os naviculare and os cuboideum, was found in 20 feet (0.6%). The os talotibiale, situated in front of the talocrural joint, was found in 16 feet (0.5%). The os sustentaculi, situated beside the sustentaculum tali, was found in 9 feet (0.3%). The talus accessorius, situated beside the trochlea tali, was found in 6 feet (0.2%). The os vesalianum, situated adjacent to the tuberositas ossis metatarsalis V, was found in 4 feet of the adult patients (0.1%). The talus secundarius, situated near the trochlea peronealis calcanei, was found in 3 feet (0.1%). The os intercuneiforme, located between first and second cuneiform and the navicular bone, was found in only one foot of a 33-year-old male (0.03%). This case may be the first observation in Japan of this extremely rare accessory ossicle. The majority of the patients who had these accessory bones in their feet and ankles seemed to have no clinical complaints. Identification of these ossicles is of importance because they may easily be mistaken as fragments of avulsion fractures. An extra center of ossification for the medical malleolus was observed in 11 feet of the children aged 8 to 11 years. The ossification center for the tuberositas ossis metatarsalis V was found in 56 feet of the adolescents...

New forms of neonatal death dwarfism. Report of 3 cases

The term Lethal Neonatal Dwarfism (Death Dwarfism) denotes bone dysplasias which always have a fatal outcome. Three different cases of "new" forms of death dwarfism are reported. A babygram should be a routine examination in all the cases of stillborn babies or those who die soon after the birth. If then the diagnosis cannot be established microscopic investigations of the growth cartilage should be performed.

Pattern comparison by interference fringe scanning

An apparatus for real-time pattern comparison based on the interference method proposed by Weinberger and Almi is described. Particular emphasis is stressed on its use in fingerprint identification. Preliminary experiments confirmed that the apparatus is feasible for the purpose.

Automatic vertometer for spherical ophthalmic lenses

A vertometer for spherical ophthalmic lenses was designed that is automated in focusing a target, in centering a lens being tested, and in marking its center within specified limits of tolerances. Light from the target is introduced into a scanning unit that detects the three-dimensional deviation of its image from a desired position and generates three signals to drive simultaneously the target and the lens so that the image of the target may come to the desired position. This procedure is followed by an automatic measurement of the deviation and marking the center, with an accuracy some five times greater than is attainable by visual examination. The working principle and experimental results are described in detail.

Holographic two-beam interferometry using multiple-reflected light beams

A holographic real-time Fizeau interferometer was devised and applied to an accurate measurement of silvered flat surfaces. It consists of recording and reconstructing light waves reflected from an air wedge between the flats, isolating a wave of the nth reflection and making it interfere with the mth beam directly reflected from the wedge. The sensitivity was enhanced by m - n, compared with the conventional interferometer. Experiment using m - n = 16 was carried out and fringes of high contrast were obtained whose interval indicates a height difference of lambda/32.