Measurement of a new parameter representing the gas transport properties of the catalyst layers of polymer electrolyte fuel cells.

The optimization of the catalyst layers is necessary for obtaining a better fuel cell performance and reducing fuel cell cost. Although the ionomer coverage of the Pt catalyst is said to be a key parameter in this regard, the proportion of Pt either directly or indirectly covered by the ionomer is thought to be an important parameter with regard to gas transport (indirectly covered Pt: its gas transport paths are completely blocked by the ionomer even if it does not directly cover Pt). In this study, a new technique has been developed for evaluating the proportion of Pt covered indirectly or directly by the ionomer, which is defined as the "capped proportion", based on the carbon monoxide (CO) adsorption properties at different temperatures.

Inhibitory effects of 16-hydroxy-9-oxo-10E,12E,14E-octadecatrienoic acid (Corchorifatty acid B) isolated from Melissa officinalis Linné on melanogenesis.

16-hydroxy-9-oxo-10E,12E,14E-octadecatrienoic acid, also known as Corchorifatty acid B (CFAB), is isolated from the ethanol extracts of the aerial parts of Melissa officinalis Linné (Labiatae) and exhibits inhibitory effects on cellular pigmentation in both human melanocytes and mouse melanoma B16 cells. CFAB specifically decreases cellular melanin by most likely inducing rapid degradation of tyrosinase in B16 cells. Interestingly, unlike other reagents that promote degradation of tyrosinase in proteasomes or lysosomes, neither proteasomal nor lysosomal inhibitors can halt CFAB-induced tyrosinase degradation.

[Angiography: clinical evaluation and physical characteristics of FPD - the clinical impact caused by detector characteristics].

We have been engaged in clinical work using DSA, the first in the world, under a joint study agreement with Hitachi Medical Corporation on the use of the Flat Panel Detector (FPD) since 2001. We are now in the stage where a certain evaluation process has been finished, but the FPD performance study in angiography has just begun, and, therefore, its clinical evaluation results are very few. Therefore, we studied the relativity between clinical images and physical characteristics in order to examine the characteristics of FPD by referencing them to clinical images.

Effects of sesquiterpene lactones on melanogenesis in mouse B16 melanoma cells.

In this study, we examined the effect of sesquiterpene lactones isolated from Calea urticifolia and Tanacetum parthenium (feverfew) on melanogenesis in mouse B16 melanoma cells. In response to 3-isobutyl-1-methylxanthin (IBMX), B16 melanoma cells underwent differentiation characterized by increased melanin biosynthesis. Treatment of sesquiterpene lactones at lower concentration (1 microM) significantly blocked IBMX-induced melanogenesis, but did not induce the inhibitory activity of cell growth.

[Experience in IVR performed using a posture support device designed especially for a patient unable to take the decubitus position].

We were requested to perform IVR for uterine artery embolotherapy of a patient who was unable to take the decubitus position. Because of extreme overweight, the patient was limited to a sitting posture on a bed in the living environment. Therefore, a device to support her sitting posture on the IVR patient table was designed and created.

[Newly developed monitor for IVR: liquid crystal display (LCD) replaced with cathode ray tube (CRT)].

For physicians who monitor images during interventional radiology (VR), we have built and been using a system that employs a liquid crystal display (LCD) instead of the conventional cathode ray tube (CRT). The system incorporates a ceiling-suspension-type monitor (three-display monitor) with an LCD on each of the three displays for the head and abdominal regions and another ceiling-suspension-type monitor (5-display monitor) with an LCD on each display for the cardiac region. As these monitors are made to be thin and light in weight, they can be placed in a high position in the room, thereby saving space and allowing for more effective use of space in the X-ray room.

[Clinical study with angiography system using a flat panel detecter].

We have been using an X-ray angiography system that incorporates a flat panel detector (FPD) since December 2001. This system is equipped with the scintillator-type FPD PaxScan 4030A from Varian Medical Systems, and for objective comparison of the image intensifier (I.I.

[An experience of the clinical study with angiography system using a Flat Panel Detector].

We had the chance of clinical studies by new proto-type Digital Subtraction Angiography (DSA) System with the Flat Panel Detector (FPD). That system has two types of detector, FPD and I.I.

Radiation-chemical properties of the hypoxic cell radiosensitizer doranidazole (PR-350).

This study was performed to confirm the radiation-chemical properties of the 2-nitroimidazole derivative doranidazole, (+/-)-(2RS,3SR)-3-[(2-nitroimdazol-1-yl)-methoxy]butane-1,2,4-triol [CAS 137339-64-1], PR-350, which was synthesized as a hypoxic cell radiosensitizer with low toxicity. Radiation-chemical experiments using doranidazole showed that (1) unlike O2, it had high reactivity toward not only hydrated electrons (eaq-), but also hydroxyl radicals (.OH), (2) the reduced intermediates of doranidasole had no ability to induce immediate strand breaks of colE1 plasmid DNA, (3) doranidazole enhanced radiation-induced DNA strand breaks of colE1 plasmid DNA in the aqueous state, whereas it did not enhance the base alteration, such as 8-oxo-deoxyguanosine, (4) it enhanced the radiation-induced formation of strand breaks with 3'-phosophate and 3'-phosphoglycolate termini, and (5) it was bound to DNA after irradiation.