Iris K Leung

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MEK1 and MEK2 are closely related, dual-specificity tyrosine/threonine protein kinases found in the Ras/Raf/MEK/ERK mitogen-activated protein kinase (MAPK) signaling pathway. Approximately 30% of all human cancers have a constitutively activated MAPK pathway, and constitutive activation of MEK1 results in cellular transformation. Here we present the X-ray(More)
Janus kinases (JAKs) are critical regulators of cytokine pathways and attractive targets of therapeutic value in both inflammatory and myeloproliferative diseases. Although the crystal structures of active JAK1 and JAK2 kinase domains have been reported recently with the clinical compound CP-690550, the structures of both TYK2 and JAK3 with CP-690550 have(More)
The single cysteine on the alpha-subunit of bovine brain S-100a protein has been modified with the thiol specific probe, Acrylodan. When the labelled apoprotein was excited at 380 nm the fluorescence emission maximum was centered at 484 +/- 2 nm, suggesting that the probe is in a fairly hydrophobic environment. Addition of Ca2+ to the protein caused the(More)
This paper presents a new robotic system that assists surgeons in manipulating the endoscope during nasal surgical procedures. The presented robotic system has four degrees of freedom (DOF) arm with a wire-driven double parallelogram mechanism to control the three orientation angles and the insertion depth of the endoscope in the nasal cavity in a decoupled(More)
The brain-specific S-100 protein is a mixture of two predominant components, S-100a and S-100b, with subunit compositions of alpha beta and beta beta respectively. In the present study, the alpha-subunit, isolated from S-100a by using anion-exchange chromatography in the presence of 8 M-urea, was homogeneous by the criteria of SDS/polyacrylamide-gel,(More)
OBJECTIVES/HYPOTHESIS To evaluate the feasibility of a unique prototype foot-controlled robotic-enabled endoscope holder (FREE) in functional endoscopic sinus surgery. STUDY DESIGN Cadaveric study. METHODS Using human cadavers, we investigated the feasibility, advantages, and disadvantages of the robotic endoscope holder in performing endoscopic sinus(More)
The brain-specific S-100 protein is a mixture of two predominant components, S-100a and S-lOOb, with subunit compositions of a,c and fl,8 respectively. In the present study, the a-subunit, isolated from S-100a by using anion-exchange chromatography in the presence of 8 M-urea, was homogeneous by the criteria of SDS/polyacrylamide-gel,(More)
We discuss the available experimental data for the singlet—triplet splitting of free and self—trapped excitons in alkali halides. These data are analysed quantitatively using the pseudopotential method of Bartram, Stonehain and Gash. The predictions confirm the trend emerging from the observed data, namely that the splittings are systematically lower for(More)
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