Search

The development of a small, light, powerful and energy-efficient superconducting magnet has been desired in order to realize better efficiency and manipulability in guiding magnetic nano-particles, magnetic organic cells and other items to the right place. This study focuses on the development of a high-temperature superconducting (HTS) bulk magnet characterized by comparatively low leak magnetism despite a relatively high magnetic field. On this basis, the authors developed a palm-sized superconducting bulk magnet, which is the world’s smallest, lightest, and lowest power consuming, as well as a new technology to effectively magnetize such a bulk magnet in a compact Stirling-cycle cryocooler (magnet C) with a pre-magnetized HTS bulk magnet (magnet B) in a compact cryocooler. This technology is demonstrated in two steps. In the first step, magnet B is magnetized using a superconducting solenoid magnet with a high magnetic field (magnet A) via the field cooling method. In the second step, magnet C is magnetized in the high magnetic field of magnet B. The prototype magnet C weighs 1.8 kg, and measures 235 × 65 × 115 mm ( L × W × H ). Magnet B was magnetized to 4.9 T using a 5 T magnet, and the target, magnet C, was magnetized using magnet B so that its maximum trapped magnetic flux density reached the value of 3.15 T. The net power consumption in a steady cooling state was 23 W, which is very low and comparable to that of a laptop computer.

o-, m-, p-Phenylenediamines having 2,3,4-trihydroxy, 3,4 dihydroxy, and 4-hydroxybenzoyl moieties were prepared and their inhibitory activities were measured against topoisomerase I and II. More hydroxy groups on two aromatic rings increased the activities. Bis(trihydroxybenzoyl)-o-phenylenediamide showed IC50=0.90 and 0.09 μM against topoisomerase I and II, respectively. Compounds with hydroxy groups protected by acetyl moiety still had the activities. Less hydroxy groups decreased their activities. Benzothiazole derivatives also indicated the activities.

One-hundred thirty-seven BALB/c mice were intranasally inoculated with neurotropic avian influenza A virus (H5N3). Thirty-nine of these mice died within 16 days post-inoculation (PID) and 98 of the mice recovered from the infection. To investigate whether viral antigens and genomes persist in the central nervous system (CNS) of recovered mice, immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) methods were performed. Histopathologically, mild interstitial pneumonia and non-suppurative encephalomyelitis restricted to the basal part of the frontal lobe of the cerebrum, brain stem and thoracic spinal cord were observed in BALB/c mice until 40 PID. Small amounts of viral antigens were detected in the brain and spinal cord and some viral RNA segments (NA, NP, M, PA, HA, NS, PB1) were intermittently detected in the CNS until 48 PID. Immunosuppression of these mice by dexamethazone (DEX) treatment did not increase the frequency of detection of the lesions, viral antigens or genomes. These findings suggest that viral genomes of neurovirulent influenza virus persist with restricted transcriptive activity in the CNS of the mice even after clinical recovery from the infection.

A large primary retroperitoneal sublumbar neoplasm was identified in an 11-year-old Holstein cow, with metastases to the lungs, kidneys and lymph nodes. The tumour cells proliferated in a characteristic endocrine pattern, were argyrophilic and positive for neuron-specific enolase, and had membrane-bounded intracytoplasmic granules. In addition, the cells were occasionally positive for cytokeratin and had desmosome-like intercellular junctions. The primary tumour mass was diagnosed as a malignant paraganglial tumour of the aortico-sympathetic ganglion (organ of Zuckerkandl), and was considered to contain primitive cells with epithelial differentiation.

A "bilayer artificial skin", composed of an inner layer of collagen sponge and an outer silicone layer, was developed by modifying the material reported by Yannas and Burke. Since our early results from experimental and clinical use of the original version of the "bilayer artificial skin" were reported, several improvements have been made in stages to eliminate some drawbacks related to disinfection and preservation and to reduce the primary cost of manufacture. The latest version of the material was successfully used in 27 sites on 23 patients. In this paper, the improvements in the material and the clinical results are described.

A bilayer artificial skin composed of a silicone sheet and a collagen sponge sheet was developed by us in 1986, modifying Yannas and Burke's technique. It was used in experimental animals and clinically, both with success; but the artificial skin was inconvenient for clinical use in terms of disinfection and preservation. In an attempt to reduce the drawbacks, we developed a re-freeze dried artificial skin. Experiments were conducted to examine whether the re-freeze dried material is equivalent to the prototype one. A significant difference between the two was found in tensile tests but not in experimental and clinical effects.

A bilayer artificial skin composed of a silicone membrane and a collagen sponge layer containing glycosaminoglycans (GAGs) was first developed by Yannas and Burke. They reported that GAGs contained in the collagen sponge layer contributed to the function of the artificial skin. In an attempt to assess the effect of GAGs in the collagen sponge layer, the electron microscopic structure, mechanical strength of collagen sponges, and cell proliferation were examined in vitro, using four kinds of collagen sponges containing: no GAG, chondroitin 6-sulphate (C6S), dermatan sulphate (DER), and hyaluronic acid (HYA). The results indicated that: (1) addition of GAGs scarcely affected the mechanical structure of collagen sponges; (2) addition of C6S and DER reinforced mechanical strength, while addition of HYA did not; (3) addition of C6S and DER significantly decreased cell proliferation.