Simultaneous determination of intraparticle diffusivity and liquid film mass transfer coefficient from a single-component adsorption uptake curve

In general, the rate of adsorption involves both rates of liquid film mass transfer and intraparticle diffusion. Many researchers tried to minimize the effect of liquid film resistance when determining the effective intraparticle diffusivity. However, in some cases (for example, small adsorbent particle size), the liquid film resistance may not be easily eliminated in a fixed bed process. Therefore, this research proposed using the shallow bed technique to determine both intraparticle diffusivity (D(S)) and liquid film mass transfer coefficient (k(F)) simultaneously from a single-component adsorption uptake curve (AUC). The task was accomplished by the determination of the Biot number (Bi) from experimental adsorption uptake curve (EAUC). The Bi represents the ratio of the rate of transport across the liquid film to the rate of intraparticle mass transfer. The detailed calculation method is addressed in this paper. The method proposed in this research can be applied in the range of Bi between 0.5 and 200 where both liquid film resistance and intraparticle diffusion are significant.     

Penicillium camemberti and Penicillium roqueforti enhance the growth and survival of Shiga toxin-producing Escherichia coli O157 under mild acidic conditions

The effects of secondary starter molds of common mold-ripened cheeses on the Shiga toxin-producing Escherichia coli (STEC) O157 were assessed in 3 model systems. In the 1st model, 8 STEC O157 strains were incubated in the spent culture of Penicillium camemberti or Penicillium roqueforti under mild acidic conditions at 25 °C. In the spent cultures of the mold at pH 4.8 to 5.0, the lag times of STEC O157 growth were significantly shorter than those observed in fresh medium. Analyses of the spent culture of P. camemberti showed that the causative agents of the growth enhancement were produced by the mold in response to an acidic environment and were not fully inactivated in heat treatment. In the 2nd model, P. camemberti and STEC O157 were cocultured in acidified milk at 25 °C. The population of STEC O157 reached 10(8) CFU/mL in the presence of the mold, whereas the population steadily declined in the absence of the mold. Although this growth enhancement was partially attributable to alkalization by the mold, it was observed even when the pH of this model was stabilized. In the 3rd model, 2 STEC O157 strains were incubated in the spent cultures of molds at pH 4.5 at 10 °C. In the spent culture, proportions of injured cells were significantly lower and D values were significantly higher than those in control, except one STEC O157 strain in the spent culture of P. camemberti. These results showed that the molds could enhance the growth and survival of STEC O157 by changing the environment. Practical Application: This study demonstrated that molds in foods can improve the growth and survival of the Shiga toxin-producing Escherichia coli O157. Because microbial interactions are ubiquitous in food, our results provide an important insight for understanding the behavior of microorganisms in food.     

Effect of mean stress on fatigue properties of 1800 MPa-class spring steels

Fatigue tests were conducted for 1800 MPa-class spring steels at various stress ratios. For comparison, similar fatigue tests were conducted for conventional steels whose tensile strength was lower than 1200 MPa. The spring steels exhibited fish-eye fractures, and the origins of these fractures were oxide, TiN and the matrix itself. In contrast, the conventional steels never exhibited fish-eye fractures. The fatigue strength of these steels decreased monotonously as the stress ratio increased, when the fatigue strength was evaluated in terms of stress amplitude. However, the fatigue strength degradation was less than that expected from a modified-Goodman line, and the best fit line was obtained by connecting the fatigue limit at zero mean stress to true fracture strength instead of tensile strength. This research also reviewed application of a power low to the stress ratio effect evaluation. In these results, the difference between the spring and conventional steels was negligible.     

Mitochonic Acid 5 Improves Duchenne Muscular Dystrophy and Parkinson’s Disease Model of Caenorhabditis elegans

Mitochonic Acid 5 (MA-5) enhances mitochondrial ATP production, restores fibroblasts from mitochondrial disease patients and extends the lifespan of the disease model “Mitomouse”. Additionally, MA-5 interacts with mitofilin and modulates the mitochondrial inner membrane organizing system (MINOS) in mammalian cultured cells. Here, we used the nematode Caenorhabditis elegans to investigate whether MA-5 improves the Duchenne muscular dystrophy (DMD) model. Firstly, we confirmed the efficient penetration of MA-5 in the mitochondria of C. elegans. MA-5 also alleviated symptoms such as movement decline, muscular tone, mitochondrial fragmentation and Ca²⁺ accumulation of the DMD model. To assess the effect of MA-5 on mitochondria perturbation, we employed a low concentration of rotenone with or without MA-5. MA-5 significantly suppressed rotenone-induced mitochondria reactive oxygen species (ROS) increase, mitochondrial network fragmentation and nuclear destruction in body wall muscles as well as endogenous ATP levels decline. In addition, MA-5 suppressed rotenone-induced degeneration of dopaminergic cephalic (CEP) neurons seen in the Parkinson’s disease (PD) model. Furthermore, the application of MA-5 reduced mitochondrial swelling due to the immt-1 null mutation. These results indicate that MA-5 has broad mitochondrial homing and MINOS stabilizing activity in metazoans and may be a therapeutic agent for these by ameliorating mitochondrial dysfunction in DMD and PD.     

In-vitro heat-generating and apatite-forming abilities of PMMA bone cement containing TiO2 and Fe3O4

Poly (methyl methacrylate) (PMMA) bone cement is widely used as a filler for repairing bone defects. To improve the effectiveness of the treatment for bone defects caused by metastatic bone tumours, we propose the formulation of PMMA cement containing titania (TiO₂) and magnetite (Fe₃O₄) that offers high bone affinity, making the cement suitable for use in magnetic hyperthermia. The TiO₂ and Fe₃O₄ contents of the PMMA cement varied from 20 to 45 mass%. The various cement samples were evaluated for their apatite-forming ability and heat-generation characteristics. The samples containing TiO₂ in concentrations of 15 mass% or higher formed apatite on their surfaces within 14 days in a simulated body fluid. The heat-generation characteristics of the samples were evaluated by applying an alternating current (AC) magnetic field under the following conditions: |H| = 40 Oe and f = 600 kHz, or |H| = 100 Oe and f = 100 kHz. The surface temperatures of the samples containing 25 and 30 mass% Fe₃O₄ reached 42.3 and 44.8 °C, respectively, at |H| = 40 Oe and f = 600 kHz. During hyperthermia treatment, cancer cells die at temperatures higher than 42 °C, and the cement samples fabricated in this study could reach this temperature. However, since some degree of heat loss will occur in vivo, it is necessary to ensure that the temperature is higher than 42 °C by varying the AC magnetic field. Nevertheless, the fact that the samples containing Fe₃O₄ concentrations of 25 mass% or higher generated enough heat under the AC magnetic field makes them suitable for clinical use in hyperthermia. Thus, PMMA cement containing 15 mass% or more of TiO₂ and 25 mass% or more of Fe₃O₄ should be investigated as a bioactive bone cement with a strong hyperthermia effect.     

Adverse effects of low-dose methotrexate therapy in rheumatoid arthritis]

To analyze the possible adverse effects of low dose methotrexate (MTX) therapy, 276 patients with rheumatoid arthritis (RA) were examined retrospectively. One hundred and seven patients (39%) experienced 113 adverse events : 57 showed liver dysfunction, 24 gastrointestinal complaints, 13 cutaneous symptoms, 6 respiratory symptoms, and 6 malignancies. Interestingly, 3 patients developed a dry cough without infiltration nor interstitial shadow on chest X-ray. The cough was rapidly resolved by discontinuation of MTX, but it recurred in 1 patient when MTX was re-administered. This finding might suggest a close association between MTX administration and the occurrence of dry cough. Of the 6 patients with malignancies diagnosed during MTX therapy, 2 showed malignant lymphoma, 2 lung cancer, 1 breast cancer and 1 colon cancer. MTX might have an oncogenic potential in RA because the coincidence rate, especially with respect to lymphoma, was significantly higher than estimated in a normal population.     

A method of seamlessly combining a crack tip molecular dynamics enclave with a linear elastic outer domain in simulating elastic–plastic crack advance

Molecular dynamics is applicable only to an extremely small region of simulation. In order to simulate a large region, it is necessary to combine molecular dynamics with continuum mechanics. Therefore, we propose a new model where molecular dynamics is combined with micromechanics. In this model, we apply molecular dynamics to the crack tip region and apply micromechanics to the surrounding region. Serious problems exist at the boundary between the two regions. In this study, we manage to solve these problems, and make possible the simulation of the process of crack propagation at the atomic level. In order to examine the validity of this model, we use α-iron for simulation. If the present model is valid, stress and displacement should vary continuously across the boundary between the molecular dynamics region and the micromechanics region. Our model exhibits just such behavior. This revised version was published online in August 2006 with corrections to the Cover Date.     

Test research in Japan

Surveys recent research activities in test technology for computers, focusing on the results of university researchers. They cover test-pattern generation, fault simulation, design for testability, built-in self-test, and self-checking     

Products of oil shale refining for the manufacture of slushing materials

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 11, pp. 15–17, November, 1989.