Seong Phun Chan

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Dental plaque deposits are known to be potent stimulants of lymphocyte transformation in patients with periodontal disease but not in normal subjects. Since plaque deposits consist mainly of whole bacteria, the cell walls of the most commonly found organisms in plaque were tested for their capacity to induce lymphocyte transformation. There was a direct(More)
This paper reports the simulation of the direct current (dc), transient, and optical characteristics of low-loss single-mode optical phase modulators based on silicon-on-insulator (SOI) material. The devices operate by injecting free carriers to change the refractive index in the guiding region and have been modeled using the two-dimensional (2-D) device(More)
The fabrication restrictions that must be imposed on the geometry of optical waveguides to make them behave as single-mode devices are well known for relatively large waveguides, with shallow etch depth. However, the restrictions for small waveguides ( 1 m or less in cross section) are not well understood. Furthermore, it is usually a requirement that these(More)
A flat spectral response has long been a requirement in photonic networking. In order to find a low cost alternative compared to some other technologies, a novel method is demonstrated to achieve such a response in silicon-on-insulator arrayed waveguide gratings (AWG) through free carrier absorption, implemented by ion implantation of dopant species. The(More)
The cell-mediated reactivity of normal individuals to staphylococcal phage lysate (SPL) were tested in vitro in the lymphocyte stimulation (LS) and leukocyte migration inhibition (LMI) assays. There were 95% positive responses in LS (stimulation ratio larger than or equal to 3 with p less than 0.01) and 67% positive responses in LMI (migration index less(More)
Infection of mice with the murine sarcoma virus (Moloney) markedly suppressed the humoral antibody response to sheep erythrocyte antigen injected 10 days after infection, when tumor size was maximal, and on day 26, when primary tumors had partially regressed. Humoral antibody response was also inhibited when antigen was injected at the time secondary tumors(More)