Efficiency of repeated batch penicillin fermentation using two fermentors. Computer simulation and optimisation

Repeated batch operation using two fermentors (RBTF) to penicillin fermentation was demonstrated by computer simulation to improve productivity. Three operation modes were compared: chemostat, repeated batch operation using a single fermentor (RBSF) and RBTF; in each case account was made of the lag period before growth. The simulated fermentor performances were assessed on the basis of the penicillin productivity and concentration; the simulation was based on published batch fermentation data. It was shown that RBTF was superior to RBSF and chemostat. The advantage of RBTF increased as the lag period became greater.     

Pressure anomaly in the paramagnetic region of bcc solid3He

The isochoric pressure of bcc Solid³He in the vicinity of the triple point has been measured by changing the temperature stepwisely and waiting for thermal equilibrium. We observed anomalous pressure kinks of the temperature dependence in the paramagnetic region near the triple point. This anomaly appeared at 0.37 to 0.40 tesla, and disappeared below 0.36 tesla. Moreover, critical phenomena at the transition point from the paramagnetic phase (PP) to the high field phase was observed and the phase line curves toward the PP side.     

IL-1 beta enhances neurite regeneration from transected-nerve terminals of adult rat DRG

We clarified the roles of IL-1 beta in peripheral neural regeneration after axotomy in a three-dimensional collagen gel culture system ranging from a single neurone to a dorsal root ganglion (DRG) explant with its associated nerve bundles. Application of 30 U/ml IL-1 beta to the culture systems clearly enhanced neural regeneration. This regeneration was evident in transected nerve terminals of DRG explants with or without associated nerve bundles, but not in dissociated single neurones. Neural survival was not affected by IL-1 beta in any of these culture systems. These results suggest that IL-1 beta stimulates surrounding non-neuronal cells to secrete neurotrophic factors, thus enhancing neurite regeneration from transected nerve terminals in cultured adult DRG explants.     

Path planning for an autonomous mobile robot considering a region with a velocity constraint in a real environment

Recently, many research projects and competitions have attempted to find an autonomous mobile robot that can drive in the real world. In this article, we consider a path-planning method for an autonomous mobile robot that would be safe in a real environment. In such a case, it is very important for the robot to be able to identify its own position and orientation in real time. Therefore, we applied a localization method based on a particle filter. Moreover, in order to improve the safety of such autonomous locomotion, we improved the path-planning algorithm and the generation of the trajectory so that it can consider a region with a limited maximum velocity. In order to demonstrate the validity of the proposed method, we participated in the Real World Robot Challenge 2010. The experimental results are given.     

On the merits of ancient Chinese eye acupressure practices

Chinese schoolchildren and adults with strenuous visual tasks routinely perform massage-and-pressure exercises on selected acupressure points around the eyes. This practice, taught by the Jing-Luo school of acupuncture for more than 4000 years, is claimed to prevent and cure myopia and other afflictions thought to result from visual close work. A four-week pilot experiment was carried out with the aim of designing a proper study on the possible short-term benefits of eye acupressure programmes. Questionnaire data revealed that the subjects did experience various eye/vision symptoms as a result of the 90 min experimental task. This could not be verified by the measurements of accommodation precision and critical flicker fusion, nor could any beneficial effects of acupressure be seen over the four experimental weeks.     

Measurement of internal stresses in coatings using time resolved fluorescence

This paper describes a new nondestructive technique for detecting internal stresses in coatings using time resolved fluorescence. The measurement principle is based upon an experimental result that the decay time of fluorescence from poly(3-octylthiophene), P3OT, dispersed in uniaxially-stretched polymer films decreases with increasing tensile stress acting on the films. Internal stresses in the clear coat and in the base coat of a multilayer structure, which was composed of electrodeposited coat, surface coat, base coat, and clear coat, were estimated from the decay time of fluorescence from P3OT in both coats. The order of internal stresses in the clear coat and base coat of the multilayer system was 1 MPa. When the coatings were piled up, the internal stress decreased as the distance from a metal substrate was increased. It was found that moisture and temperature influenced internal stresses in the clear coat rather than in the base coat. Internal stress in the clear coat, which was one layer coated on a metal substrate, was measured by the traditional bimetallic method or by the time resolved fluorescence technique. Comparing both methods, it was concluded that the time resolved fluorescence technique gave reliable values for internal stresses in coatings.     

New amphoteric surfactants containing a phosphoric acid group: I. syntheses and physicochemical properties of sodium 2-(n-2-hydroxyalkyl-n-methylamino)ethyl hydrogen phosphate

A series of new amphoteric surfactants having a phosphoric acid group, a tertiary amino group and a 2-hydroxyalkyl group, sodium 2-(N-2-hydroxyalkyl-N-methyl-amino)ethyl hydrogen phosphates (alkyl: n-tetradecyl, n-hexadecyl, n-octadecyl), were prepared by an addition reaction of 1,2-epoxyalkanes to N-methylaminoethanol, followed by the introduction of a phosphoric acid group and neutralization with sodium hydroxide. The structures of these compounds were confirmed by spectroscopy and elemental analysis. The solubility in solvents, Krafft point, surface tension, critical micelle concentration (CMC), occupation area of the molecule at the surface of aqueous solutions and foaming power were measured. It was shown that a 2-hydroxyethyl group in a long alkyl chain seemed to behave as a hydrophobic part.     

The distribution of soap in the polymerization system for preparation of carboxylated polystyrene latexes

The distribution of soap in the polymerization system for preparation of carboxylated polystyrene latexes has been investigated. The critical micelle concentration (CMC) for sodium dodecyl sulfate (SDS) in the polymerization system was determined by surface tension measurement to be 0.173 mmole/l. The solubility of styrene (St) in the aqueous phase of the polymerization system was determined by NMR measurement to be 4.52 mmole/l. It was confirmed by NMR measurement that at the concentration of SDS higher than the CMC, St is solubilized in the interior of the SDS micelles, and the concentration of solubilized St is almost proportional to the concentration of micellar SDS. From this relationship, the number and radius of SDS micelles containing solubilized St can be determined.     

Preparation of Silicon Carbide and Aluminum Silicon Carbide from a Montmorillonite–Polyacrylonitrile Intercalation Compound by Carbothermal Reduction

Both silicon carbide and aluminum silicon carbide have simultaneously been obtained directly from naturally occurring aluminosilicate by carbothermal reduction for the first time. A precursor of a montmorillonite–polyacrylonitrile (PAN) intercalation compound was heated at 1700°C in Ar. For comparison, montmorillonite–carbon mixtures were similarly heated. α-SiC, β-SiC, and Al₄Si₂C₅ formed from the montmorillonite–PAN intercalation compound. Mainly α-Al₄SiC₄ was obtained with ternary carbides from the montmorillonite–carbon mixtures in addition to a large amount of β-SiC. Hence, aluminum silicon carbide formation was affected by the mixing condition of the starting materials.