Effects of transforming growth factors on dopaminergic neurons in culture

It was recently reported that TGF-beta 1 either had no significant effect on or increased the survival of dopaminergic neurons in culture. TGF-beta 2 and TGF-beta 3 were reported to cause increased survival or to greatly inhibit survival. The transforming growth factors are a highly pleiotropic group of compounds, and the above results suggest that their actions may be critically dependent on the conditions of the assay. We have therefore tested these compounds under optimal conditions of culture, in a medium containing a low (2.5%) concentration of fetal bovine serum. TGF-beta 2 and 3 inhibited neuronal (MAP2-pos) survival only at the highest concentration (10 ng/ml) tested, while inhibition of survival of dopaminergic neurons was observed at 1.0 and 10 ng/ml. These results therefore suggest that the inhibitory action of TGF-beta 2 and 3 on the survival of dopaminergic neurons in culture, under the experimental conditions outlined, may be relatively specific.     

Quantitative evaluation of diabetic gastrointestinal paresis by measuring transit time of the stomach and the digestive canal

Our subjects comprised eighty six diabetes mellitus (DM) patients without severe complication. To evaluate gastrointestinal motility quantitatively, we measured gastric emptying time by acetaminophen (APAP) method using serum APAP value and oro-cecal transit time (OCTT) by lactulose hydrogen breath test in the subjects and normal controls (NC). Comparing DM patients and NC, mean APAP value was lower and mean OCTT was prolonged in the former. Analysing DM patients' background, patients with peripheral neuropathy had prolonged OCTT than patients without neuropathy did. Comparing patients with higher HbA1c levels and patients with normal HbA1c levels, mean APAP value, which was closer to normal levels, was higher in the former. Analysing symptoms, some of them were apparently related to abnormal gastrointestinal motility. From these results, it was concluded that measuring both gastric emptying and OCTT was a useful method to evaluate slight abnormal motility in DM patients.     

Joining of ADC12 and SS400 by means of friction stir welding

For conserving the earth's environment through the reduction of energy consumption in the field of transport machinery, reduction in weight is necessary and hence the application of light materials to structural members has been investigated. For the most representative example of transport machinery, it is highly likely that a variety of aluminium materials will be used for automobile bodies. However, since iron and steel materials are still used for the main part of the structure that requires high strength, joining of dissimilar metals, i.e. aluminium and iron and steel materials, is the new technical task in terms of reducing weight.     

Performance evaluation of heat exchanger using alternative refrigerant R407C

R22 (HCFC22) has been widely used as the refrigerant in air conditioners. According to the Montreal protocol for ozone layer protection, the total production of HCFCs has been capped since the beginning of 1996. Zeotropic refrigerant mixture R407C and nearly azeotropic refrigerant mixture R410A have been selected as alternatives to R22. We examined refrigerant passages in heat exchangers used in heat pump‐type room air conditioners using zeotropic refrigerant R407C through simulation, and obtained the following conclusions. In an indoor heat exchanger, a counter flow configuration when operating as a condenser has higher temperature efficiency. When an outdoor heat exchanger operates as an evaporator, a configuration that suppresses the temperature glide by partially reducing the refrigerant passage not only produces high efficiency, but also reduces the frost formation on fins. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(8): 626–638, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10064     

Spontaneous stratification in composite films consisting of conjugated polymers and neat C60 prepared by electrophoretic deposition

The morphology of composite films consisting of conjugated polymers and C₆₀ prepared by electrophoretic deposition (EPD) has been studied. While C₆₀ exists as nanocrystals uniformly embedded in the composite films based on poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene], a spontaneous stratification of the composite films into polymer-C₆₀-mixture and C₆₀-microcrystal layers is observed in the films based on a polyfluorene derivative, poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}]. The results suggest that EPD can be a useful tool for controlling the morphology of bulk heterojunction systems for organic photocells.     

Rapid erasing of wettability patterns based on TiO2-PDMS composite films

TiO₂-polydimethylsiloxane (TiO₂-PDMS) composite films are prepared using the sol–gel method from a Ti(OBu)₄–benzoylacetone solution containing PDMS. The prepared films are cured by irradiation with ultraviolet (UV) light. Structural changes in the films after UV irradiation are confirmed by UV–vis absorption experiments, which show that an absorption band characteristic of the benzoylacetonate chelate rings disappears. This finding is ascribed to structural changes associated with the dissociation of the chelate rings. The IR spectra of the thin films exhibit a broad absorption band after UV irradiation, indicating that a Ti–O–Ti network forms in the thin film. Contact angles are measured for the TiO₂-PDMS thin films, showing wettability conversion from hydrophobic to superhydrophilic states by irradiation with oxygen plasma for 1 s. This phenomenon is explained by XPS experiments which reveal that the number of carbon atoms decreases, whereas the number of oxygen atoms increases on the surface of the TiO₂-PDMS composite films. Finally, hydrophobic–superhydrophilic patterns are fabricated based on a patterned TiO₂-PDMS composite film. The film displays a rapid change to superhydrophilicity over the whole film surface upon plasma irradiation for 1 s, which means that the wettability patterns are rapidly erasable.     

A QoS-aware routing mechanism for multi-channel multi-interface ad-hoc networks

To accommodate real-time multimedia application while satisfying application QoS requirements in a wireless ad-hoc network, we need QoS control mechanisms. In this paper, we propose a new routing mechanism to support real-time multimedia communication by efficiently utilize the limited wireless network capacity. Our mechanism considers a wireless ad-hoc network composed of nodes equipped with multiple network interfaces to each of which a different wireless channel can be assigned. By embedding information about channel usage in control messages of OLSRv2, each node obtains a view of topology and bandwidth information of the whole network. Based on the obtained information, a source node determines a logical path with the maximum available bandwidth to satisfy application QoS requirements. Through simulation experiments, we confirmed that our proposal effectively routed multimedia packets over a logical path avoiding congested links. As a result, the load on a network is well distributed and the network can accommodate more sessions than QOLSR. We also conducted practical experiments using wireless ad-hoc relay nodes with four network interfaces and verified the practicality of our proposal.     

Approach and structure of stabilizing control system preventing an extension of synchronism loss

Recently, large-capacity power stations have been built far from load centers with long-distance transmission lines. Therefore, if a fault occurs at the line, generators in the large-capacity power station may lose synchronism from the remaining generators [1, 3]. To prevent an extension of loss of synchronism to other generators, fast shedding of some generators is an effective measure. The following methods have been proposed so far: A method [3] based on energy function approach; and a method [2] which estimates and predicts the relative swing among generators using data measured on-line at each generator and proposes shedding some generators for stabilization. This method requires a large communication network for an exchange of data between power stations. This paper presents a new stabilizing method and a newly developed stabilizing control system which does not require a large communication network because it utilizes generator output, voltage and current measured on-line in the vicinity of the large-capacity power station. Using these measured data, the system estimates and predicts the relative swing between generators in the large-capacity power station and the remaining generators. Finally, the number of generators to be shed for stabilization is decided and shedding is performed. Configuration and characteristics of the developed stabilizing control system are shown. The validity of this method is confirmed by simulation and testing using an artificial power system.