Andrew C. Tam

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Arthrobacter sp. strain TE1 isolated from s-ethyl-N,N-dipropylthiocarbamate (EPTC)-exposed soil degraded this herbicide effectively and could grow on EPTC as the sole carbon source. TE1 harboured four plasmids of 65.5, 60, 50.5, and 2.5 megadaltons. Spontaneous mutants unable to degrade EPTC arose at a high frequency, and this was further increased by(More)
A pulsed dye-laser optoacoustic spectroscopy technique has been used to measure the absorption spectra of light and heavy water at 21.5 degrees C in the visible region. Basic principles of pulsed optoacoustic spectroscopy technique and the procedure for absolute calibration are discussed with reference to its application in water. Experimental details of(More)
A cDNA molecule encoding the human GABA transporter was synthesized by means of polymerase chain reaction (PCR) technique and used as probe for selecting a human genomic DNA fragment encoding GABA transporter. A positive clone harboring the whole gene was obtained from a human lymphocyte genomic library through utilizing the genomic 'walking' technique. The(More)
OBJECTIVE We tested the ability of Notch pathway receptors Notch1 and Notch2 to regulate stem and epithelial cell homoeostasis in mouse and human gastric antral tissue. DESIGN Mice were treated with the pan-Notch inhibitor dibenzazepine (DBZ) or inhibitory antibodies targeting Notch1 and/or Notch2. Epithelial proliferation, apoptosis and cellular(More)
The thermodynamics of the rapid vaporization of a liquid on a solid surface heated by an excimer laser pulse is studied experimentally. The transient temperature field is measured by monitoring the photothermal reflectance of an embedded thin film in nanosecond time resolution. The transient reflectivity is calibrated by considering a temperature gradient(More)
The transmission of uncoated and antireflection (AR)-coated CaF(2) windows has been measured during long KrF laser exposures. Samples were tested for up to 75 million pulses in front of an industrial-grade KrF excimer laser at high repetition rates (200-300 Hz) and moderately high energy fluence (220-550 mJ/cm(2)). In this fluence range bare CaF(2) performs(More)
Frequency-modulation spectroscopy was employed successfully to measure the Doppler-free absorption and dispersion signals originating from several two-photon transitions in (85)Rb and (87)Rb. The two-photon cross section of the hyperfine transition 5S(1/2) (F = 2) ? 5D(5/2) (F = 4) in (87)Rb was determined to be sigma((2)) asymptotically equal to 4 x(More)
The threshold for explosive vaporization of a liquid layer on an opaque solid surface heated by an ultraviolet excimer pulsed laser is studied by a photoacoustic probe-beam deflection method. The probe beam traverses the liquid in the vicinity of the laser-heated liquid-solid interface. Below the explosion threshold, photoacoustic generation in the solid(More)
—A KrF excimer laser projection micromachining tool has been designed and implemented aiming to accomplish one-step etching with micron resolution for applications such as chip module packaging and polyimide technology in semiconductor manufacturing. Two polyimide (Probimide 7020) thin films spun on the silicon wafers are annealed at 100 C and 400 C,(More)