CT diagnosis of pleural dissemination without pleural effusion in primary lung cancer

We retrospectively reviewed the CT scans of 25 primary lung cancers with disseminated pleural nodules or minimal malignant pleural effusions that were not recognized preoperatively. Special attention was devoted to abutting interlobar fissures, thick major fissures, and disseminated nodules on the chest wall, the diaphragm, and in the interlobar fissures. Among 10 primary tumors abutting interlobar fissures, nine (90%) had at least one of these findings. Among 15 primary lung tumors which did not abut interlobar fissures, four (27%) had at least one of these findings. We conclude that CT is a useful modality for detecting the pleural dissemination of primary lung cancers when primary lung cancers abut interlobar fissures even if no pleural effusion is detectable on CT.     

The improvement of irradiation-enhanced copper embrittlement in FeCu alloys

The effect of alloying elements on neutron irradiated FeCu alloys has been investigated in order to obtain the fundamental information on the irradiation-enhanced copper embrittlement for power reactor vessel steels. The mechanism of copper-induced irradiation embrittlement in the copper-containing iron alloys was proved to be due to both the interaction of copper atoms with irradiation-produced complex defects within grains, and the preferred grain boundary segregation of copper atoms existing near grain boundaries. The former effect causes the increase of yield strength, and the latter results in the ductility loss and grain boundary crackings. The addition of titanium up to 0.4 wt% to the Fe-0.1 wt% Cu alloy was found to be extremely effective in the improvement of both the irradiation-induced ductility loss and strength. Aluminum and silicon were not as effective as titanium.     

Mechanical properties of ferrous alloys after fast neutron-irradiation at high temperature

The results are given of an international “round-robin” experiment to study the nature of the damage structure in neutron irradiated zirconium and zircaloy-2 using transmission electron microscopy. The damage structure consists entirely of $\text{1}\text{3}\text{α<11}\text{2}\text{?}\text{0>}$ dislocation loops and no evidence has been found for c-component loops. Both vacancy and interstitial loops were found in specimens irradiated at 400 °C, with an excess of vacancy loops. Quantitative measurements of loop size distributions and loop concentrations are reported. All specimens exhibited “corduroy” contrast to varying degrees. The importance of choice of imaging conditions to minimize the contrast from thin foil artefacts such as oxide films and surface hydrides is stressed. The significance of the results is briefly discussed with reference to current theories of irradiation growth.     

Introduction of a biochemical allosteric property for creating a new electronic signal transmission system under the time-minimum optimization

We introduce and allosteric property of enzymes on biological membranes to create a new electronic signal transmission system. In the allosteric enzymes, sequential binding of substrates, activators, and inhibitors induces molecular conformational changes in subunits of the inactive allosteric enzymes. By this binding, the enzyme is partially activated. Successive binding of the substrates accelerates the structural change in the subunits and activates the enzyme progressively. Based on reported biological experimental data, we expressed the complicated activation and inactivation processes of the allosteric enzyme reaction system by 20 rate equations. We proposed a time-minimum optimal control strategy for the allosteric reaction system as a dominating principle. This is because the biochemical, signals have to be transmitted as quickly as possible to achieve their purpose, particularly for life-saving defense, reactions to harmful exogenous disturbances. The present mathematical model describes the complicated sequential, information transmission processes of the biochemical reactions. We can show that the allosteric effect had a marked influence on species conversion. With the increases in allosteric parameters, the concentrations of all species changed more rapidly and in larger amounts than they did at the standard allosteric parameter values. This meant that increasing the allosteric activity of the subunit accelerates the reactions and enhances the reactive production. Hence, the allosteric property is important for high-speed, extensive signal transmission among the components that constitute a complicated network circuit. This property, when it is linked with the time-optimal controller, will create a new signal transmission device. This work was presented, in part, at the Fourth International Symposium on Artificial Life and Robotics, Oita, Japan, January 19–22, 1999.     

Is Inflammation a Friend or Foe for Orthodontic Treatment?: Inflammation in Orthodontically Induced Inflammatory Root Resorption and Accelerating Tooth Movement

The aim of this paper is to provide a review on the role of inflammation in orthodontically induced inflammatory root resorption (OIIRR) and accelerating orthodontic tooth movement (AOTM) in orthodontic treatment. Orthodontic tooth movement (OTM) is stimulated by remodeling of the periodontal ligament (PDL) and alveolar bone. These remodeling activities and tooth displacement are involved in the occurrence of an inflammatory process in the periodontium, in response to orthodontic forces. Inflammatory mediators such as prostaglandins (PGs), interleukins (Ils; IL-1, -6, -17), the tumor necrosis factor (TNF)-α superfamily, and receptor activator of nuclear factor (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) are increased in the PDL during OTM. OIIRR is one of the accidental symptoms, and inflammatory mediators have been detected in resorbed roots, PDL, and alveolar bone exposed to heavy orthodontic force. Therefore, these inflammatory mediators are involved with the occurrence of OIIRR during orthodontic tooth movement. On the contrary, regional accelerating phenomenon (RAP) occurs after fractures and surgery such as osteotomies or bone grafting, and bone healing is accelerated by increasing osteoclasts and osteoblasts. Recently, tooth movement after surgical procedures such as corticotomy, corticision, piezocision, and micro-osteoperforation might be accelerated by RAP, which increases the bone metabolism. Therefore, inflammation may be involved in accelerated OTM (AOTM). The knowledge of inflammation during orthodontic treatment could be used in preventing OIIRR and AOTM.     

Study of local oxidative degradation in polypropylene impact copolymer by energy dispersive X-ray system

Summary In this study, the thermal oxidative degradation of a polypropylene (PP) impact copolymer was examined using a transmission electron microscope equipped with an energy dispersive X-ray system (TEM/EDX). The oxidative behavior was visually captured by oxygen line analysis. The oxidation resistance of the ethylene-propylene rubber (EPR) phase was considerably higher than that of the PP matrix, indicating that the degradation behavior of the PP impact copolymer was heterogeneous. It was found that the higher resistance of the EPR phase originated from its primary structure by ¹³C-NMR measurement.     

Salt effects on the conformation of a ‘statistical’ copolymer of l-leucine and l-lysine

For studying the influence of water structure breaking and making anions on the conformation of poly(α-amino acids) containing hydrophobic and ionic side chains, c.d. measurements on ‘statistical copolymers of l-leucine and l-lysine were carried out in LiClO₄, NaClO₄, Li₂SO₄, Na₂SO₄, KF, NaF, and NaCl solutions and also in salt-free water. Copolymers with 50 mol% l-leucine do not form α-helices in pure water at pH 7 (20°C); however LiClO₄ and NaClO₄ at concentrations as low as 0.003 moll^?1 induce α-helix formation almost independent of cation. Surprisingly, not only ClO^?₄ but also SO^2?₄ has an α-helix inducing effect in this case, in contrast with basic homopoly (α-amino acids), where such an effect of SO^2?₄ was not observed. Therefore the presence of l-leucyl residues seems to be responsible for this α-helix inducing effect of sulphate anions. This agrees with the fact that sulphate stabilizes the ordered periodic conformation of native proteins as the increase of denaturing temperature shows. It can be assumed that the results of these measurements support the assumptions on the influence of water structure in making SO₄ anions on hydrophobic interactions, as well as of water structure breaking ClO₄ anions.