It is well known that conventional bubbling humidifiers are capable of producing micro-aerosols contaminated with bacteria. We developed a unique humidifier, named a membrane humidifier, that does not require an external water supply. This new system obtains moisture from room air. We investigated the clinical and in vitro evaluation of the membrane humidifier. Ten patients with chronic pulmonary disease participated in the study. We evaluated the partial pressure of oxygen in arterial blood (PaO2) of 10 patients who used the new device. We conducted an in vitro study to determine whether the device could prevent the bacterial contamination of humidified-oxygen. We passed compressed air contaminated with Pseudomonas aeruginosa outside the hollow fibres of the membrane humidifier, and the humidified-oxygen passed inside the hollow fibres was sampled into nutrient broth periodically for 10 days. We also compared the relative humidity of oxygen humidified by a membrane humidifier with that of oxygen humidified by a bubbling humidifier. There was no significant difference between measured PaO2 while breathing oxygen humidified using a membrane humidifier and that while breathing oxygen humidified using a bubbling humidifier. Cultures of the humidified-oxygen passed through the hollow fibres were negative for bacteria. The membrane humidifier could produce good humidification. The new device appeared to prevent bacterial contamination, and may help to reduce the risk of infection in patients at hospital and home.

This study is aimed at developing a small-sized air pump using an originally contrived balloon vibrator for wearable devices. The developed pump can compress air by vibrating a balloon vibrator which is composed of a doughnut-shaped balloon diaphragm fitted with a circular stainless steel plate. The balloon diaphragm is filled with air. This pump has characteristics as an oil-free, doesn't leak air at all, and has a longer stroke than existed diaphragm pumps. Therefore, this pump is expected to have higher discharge performance than existed diaphragm pumps. In addition, it is also expected to develop an output variable air pump by controlling the inner pressure of balloon. In this paper, the structure of the developed pump is described, and then the fundamental characteristics of this pump are evaluated.

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The clinical utility of the newly developed pressure swing adsorption (PSA)-type oxygen concentrator with a membrane humidifier that does not require added water for humidification was evaluated in 13 patients with chronic pulmonary disease who were receiving long-term oxygen therapy. PaO₂ and the relative humidity were measured when the patient breathed air and oxygen from the new device via a nasal cannula. After using the new concentrator for 5 h, the patients were asked whether they experienced dry nasal passages or a dry throat. A significant difference between the PaO₂ measured while the patients breathed room air and while they breathed oxygen from the new device was observed. A significant difference was observed between the relative humidity of room air (44.7 ± 18.6%) and that of the oxygen flow (72.7 ± 14.8%) from the new device. None of the patients experienced dry nasal passages, dry throat, or any other adverse effects. Since this new PSA-type oxygen concentrator with a membrane humidifier supplies well-humidified nasal oxygen without water, laborious cleaning of the container and changing of the water are not necessary, and may help to improve the patient’s quality of life.

A b8troct-This paper fllat describes the architecture of the Network Digital Camera. Then, e real-time streaming system using the Network Digital Camera, an Access Point (AP) end e Digital Photo Album is proposed and evaluated. The evaluation ia baaed on the characteristics of packet transmisdan time, which depends on two varying perametera, namely, the condition and population of the wireless environment.