• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.1051-1054
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• 2000

We developed the micro CSF (celebrospinal fluid) shunt valve with surface and bulk micromachining technology in polymer MEMS. This micro CSF shunt valve was formed with four micro check valves to have a membrane connected to the anchor with the four bridges. The up-down movement of the membrane made the CSF on & off and the valve characteristic such as open pressure was controlled by the thickness and shape of the bridge and the membrane. The membrane, anchor and bridge layer were made of the $O_2$ RIE (reactive ion etching) patterned Parylene thin film to be about 5~10 microns in thickness on the silicon wafer. The dimension of the rectangular nozzle is 0.2＊0.2 $\textrm{mm}^2$ and the membrane 0.45 mm in diameter. The bridge width is designed variously from 0.04 mm to 0.12 mm to control the valve characteristics. To protect the membrane and bridge in the CSF flow, we developed the packaging system for the CSF micro shunt valve with the deep RIE of the silicon wafer. Using this package, we can control the gap size between the membrane and the nozzle, and protect the bridge not to be broken in the flow. The total dimension of the assembled system is 2.5＊2.5 $\textrm{mm}^2$ in square, 0.8 mm in height. We could precisely control the burst pressure and low rate of the valve varing the design parameters, and develop the whole CSF shunt system using this polymer MEMS fabricated CSF shunt valve.

• The Journal of the Korean Society for Microbiology
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• v.13 no.1
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• pp.1-5
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• 1978

Listeria monocytogenes infection was considered a rather rare disease and occurs mostly either in newborn babies or in young children. However, there has been increasing reports of this infection in elderly person with various underlying disease. Recently we have experienced two cases of Listeria meningitis; one in a 4-year-old male with an acute lymphoblastic leukemia, and the other in a 43-year-old female with a breast cancer. Both were on various chemotherapeutic agents for their primary diseases when the organism, L. monocytogenes was found in their celebospinal fluid(CSF). The degree of CSF pleocytosis were quite different by cases. The former case showed a marked increase, $3,350/mm^3$, and the latter slight, $410/mm^3$, Both showed a slight decrease of CSF glucose ranging 39 to 43mg/100ml. It seems that a routine CSF analysis bears a limitted value in the diagnosis or Listeria meningitis. A direct smear of CSF with Gram's stain revealed gram-positive bacilli in one case, but none in the other. Bacterial culture of CSF yielded plenty colonies in one case, but a few in the other. It seems that isolation of L. monocytogenes must not be considered very easy, and a negative direct smear does not necessarily mean a negative culture. The two isolates we obtained showed the typical cultural and biochemical characteristics of L. monocytogenes and were found to belong to serotypes 1b and 4b. It was our experience that the identification of this organism was not very much matter because of its distinct characteristics, but the most important matter was how to think of the possibility of this organism at the begining. The two isolates were both susceptible to cephalothin, chloramphenicol, erythromycin, tetracycline and gentamicin; intermediate to ampicillin, penicillin and kanamycin; and resistant to cloxacillin.