Optical-Fiber Feedthrough in Pressure Housing

The structure for introducing fibers into the pressure housing of a submarine optical repeater is studied. As a result of investigations into sealing materials, fiber strength, and optical characteristics, the following structure is adopted. Fibers, whose primary coat is metal instead of silicone, are fixed by epoxy resin to withstand water pressure, and the outside surface of the resin is covered with solder to keep the resin free from water vapor. Experimental results show that this structure meets the requirements.     

Selective Ion Permeation Across Membranes Prepared from Steroidal Crown Ethers

Five crown ethers covalently-linked to the cholesterol skeleton were synthesized. Thermal analysis established that four of them have a cholesteric liquid-crystal phase. In particular, the monobenzo-13–crown-4 covalently-linked through an ethylene spacer to the cholesterol skeleton shows a stable cholesteric mesophase even at room temperature. The stable cholesteric mesophase at room temperature was also obtained by mixing two steroidal crown compounds. These mixed systems were embedded in a polymer matrix and the polymer/liquid-crystal composite membranes were subjected to ion-permeation experiments. It was found that the permeation selectivity is basically explained by the hole-size selectivity in the crown-metal interaction. In particular, composite membranes containing a monobenzo-13–crown-4 unit showed the remarkably high Li⁺ selectivity. It was concluded on the basis of examination of activation parameters that ion permeation occurs across channel-like stacks of crown ether rings.     

Nodular glomerulosclerosis of unknown origin associated with the nephrotic syndrome

A 35-year-old male patient clinically characterized by massive proteinuria and hypertension without evidence of systemic diseases is reported. Histological investigation of renal biopsy specimens revealed extensive nodular formations in the mesangial areas in every glomerulus. Light-microscopic examination did not allow discrimination between the glomerular changes found in these specimens and the nodular glomerulosclerosis described in patients with diabetes mellitus. Electron-microscopic examination confirmed the presence of massive, nodular, mesangial expansions consisting of finely fibrillar substances without electron-dense deposits and circumferential mesangial interposition. Immunofluorescent examination showed deposition of IgG, C3, fibrinogen and kappa and lambda light chains in mesangial areas, peripheral capillary loops and a part of the nodules. Furthermore, collagen types IV, V, VI and laminin were detected in the nodules. Amyloid was not observed in these nodules. This diagnosis has not been made, and the mechanism of this nodular glomerulosclerosis remains unknown.     

Solid-liquid interfacial energy of non-metallic bonded elements

Based on homogeneous nucleation theory, the temperature dependence of the nucleation frequency for crystallization is calculated for a supercooled liquid. Here the solid-liquid interfacial energy of an alloy is estimated by means of an extension of Turnbull's assumption. Equations are suggested which correlate the energy with the ionization energy and the entropy of fusion for non-metallic bonded elements.     

The involvement of calpain-dependent proteolysis of the tumor suppressor NF2 (merlin) in schwannomas and meningiomas

Neurofibromatosis type 2 (NF2) protein, also known as merlin or schwannomin, is a tumor suppressor, and NF2 is mutated in most schwannomas and meningiomas. Although these tumors are dependent on NF2, some lack detectable NF2 mutations, which indicates that alternative mechanisms exist for inactivating merlin. Here, we demonstrate cleavage of merlin by the ubiquitous protease calpain and considerable activation of the calpain system resulting in the loss of merlin expression in these tumors. Increased proteolysis of merlin by calpain in some schwannomas and meningiomas exemplifies tumorigenesis linked to the calpain-mediated proteolytic pathway.     

Receptor-mediated and receptor-independent activation of G-proteins in rat brain membranes

High-affinity GTPase activity intrinsic to G-proteins, which serves as an index of G-protein activation elicited through agonist-stimulated receptors as well as by receptor-independent direct G-protein activators like mastoparan, was measured in rat brain membranes. Receptor-mediated high-affinity GTPase activity was detectable preferentially for the Gi subfamily associated with adenylyl cyclase inhibition mediated by group II metabotropic glutamate, pirenzepine-insensitive muscarinic acetylcholine, GABA(B), adenosine A1, dopamine D2-like (striatum), and serotonin 5-HT1A (hippocampus) receptors. The pharmacological characteristics of such receptor-mediated high-affinity GTPase activities were presented. Mastoparan, a tetradecapeptide from wasp venom which has been shown to directly activate Gi and Go, inhibited low-affinity GTP hydrolyzing activity, probably due to its activating effect on nucleoside diphosphokinase (NDPK). When NDPK activity was inhibited completely by UDP, mastoparan stimulated high-affinity GTPase activity in a concentration-dependent manner. There are many compounds other than mastoparan with apparently diverse structural properties which have been shown to directly activate G-proteins. The relevance and possible participation of receptor-independent mode of G-protein activation for some neuropeptides were discussed.     

Topographical relationship between sucrase and leucine beta-naphthylamidase on the microvilli membrane of rabbit intestinal mucosal cells

The topographical relationship between sucrase [EC 3.2.1.26] and leucine beta-naphthylamidase (LNAase) on the microvilli membrane of rabbit small-intestinal mucosal cells was studied assuming that where enzymes with different antigenicities, A and B, are situated in close proximity on the surface of microvilli vesicles, the agglutination of vesicles by anti-A antibody is inhibited by the previous binding of monovalent fragments of anti-B antibody to enzyme B on the surface of vesicles. Like anti-sucrase antibody, anti-LNAase antibody quantitatively agglutinated microvilli vesicles. It inhibited the membrane-bound LNAase activity in the same manner as the detergent-solubilized activity. This inhibitory effect of anti-LNAase antibody was not interfered with by monovalent fragments of anti-sucrase antibody. However, the monovalent fragments inhibited vesicle agglutination by anti-LNAase antibody as well as by anti-sucrase antibody. These results indicate that LNAase is located on the outer surface of microvilli vesicles and suggest that LNAase and sucrase are situated in close proximity on the membrane surface of microvilli vesicles.     

Prediction of equivalent environments by energy exchange and assessments of physiological strain and discomfort

The described equivalence postulate was confirmed experimentally by examining physiological responses as well as discomfort sensation in a series of predicted equivalent conditions during exercise (congruent to 3 met). ET or the equivalent Ta at 50% RH is a single independent variable that is uniquely related to the mean skin temperature (Tsk), skin wettedness (w), body core temperature (Tcore) and sense of discomfort.     

Effects of manufacturing conditions on the properties of coal-derived caking additives

Manufacturing conditions of coal-derived caking substances (SRC) were investigated to determine the effects of these conditions on the chemical and caking properties of the additives. The solvent-refined coal (SRC) produced in the early stage of digestion at the lower temperature, of which β- and γ-fractions were 55 and 35 wt %, respectively, consisted of a heterogeneous mixture characterized by a low aromaticity, long side-chains, and a large, average molecular weight. The Roga index of the SRC was large but its total dilatation was small. As the digestion proceeded, the condensation and the cycloaromatization reactions improved the homogeneous nature and decreased the molecular weight by the breakage of side-chains, dealkylation, and deoxidation, leading to increases in the γ-fraction and total dilation by decreases in the β-fraction and Roga index. Such trends were more marked when the conversion exceeded 90 wt %. The relation between structure and the caking properties of the SRC are discussed.