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Papers by Qing Chen

Research paper thumbnail of Analysis of ethylene signal-transduction kinetics associated with seedling-growth response and chitinase induction in wild-type and mutant arabidopsis

Plant Physiology, 1995

Kinetic aspects of ethylene-mediated signal transduction leading to seedlinggrowth inhibition and... more Kinetic aspects of ethylene-mediated signal transduction leading to seedlinggrowth inhibition and chitinase induction in Arabidopsis were investigated by the introduction of defined mutations in components of these pathways. Dose-response analysis of wild-type responses indicated that the rate-limiting steps for seedling responses and Arabidopsis basic-chitinase induction displayed Michaelis-Menten kinetics with apparent dissociation constants of the response (K,) of 0.1 and 1.4 pL 1-' ethylene, respectively. In the ethylene-insensitive efrl-l and ein2-32 mutant lines, both Arabidopsis basíc-chitinase induction and seedling-growth responses were completely disrupted, whereas the weaker efrl-2 allele eliminated the chitinase-induction response but only partially disrupted the seedling responses. A heterologous reporter gene containing the chitinase promoter from bean (bean basic-chitinase-/3-glucuronidase) displayed subsensitive kinetics (K, 120 pL L-' ethylene) compared to the response of the endogenous basic-chitinase response (K, 1.4 p L L-' ethylene). A model for ethylene signal transduction that accounts for the observed variations in ethylene dose-response relationships is presented. The relationship between the model and the biochemical mechanisms of well-characterized signal-transduction systems in animals is discussed.

Research paper thumbnail of Robust Quantization for Image Coding and Noisy Digital Transmission

A robust quantizer is developed for encoding a variety of memoryless sources and transmission ove... more A robust quantizer is developed for encoding a variety of memoryless sources and transmission over the binary symmetric channel (BSC). The system combines channel optimized scalar quantization (COSQ) with all-pass filtering, the latter performed using a binary phase-scrambling/descrambling method. Applied to a broad class of sources, the robust quantizer achieves the same performance as the Gaussian COSQ for the memoryless Gaussian source. This quantizer is used for image coding for transmission over a BSC. An explicit error protection code is used only to protect the side information. The PSNR performance degrades gracefully as the channel bit error rate increases

Research paper thumbnail of Image coding using robust quantization for noisy digital transmission

IEEE Transactions on Image Processing, 1998

A robust quantizer is developed for encoding memoryless sources and transmission over the binary ... more A robust quantizer is developed for encoding memoryless sources and transmission over the binary symmetric channel (BSC). The system combines channel optimized scalar quantization (COSQ) with all-pass filtering, the latter performed using a binary phase-scrambling/descrambling method. Applied to a broad class of sources, the robust quantizer achieves the same performance as the Gaussian COSQ for the memoryless Gaussian source. This quantizer is used in image coding for transmission over a BSC. The peak signal-to-noise ratio (PSNR) performance degrades gracefully as the channel bit error rate increases

Research paper thumbnail of Bone morphogenic protein-7 (BMP7), a novel therapy for diabetic nephropathy1

Kidney International, 2003

Conclusion. BMP-7 partially reversed diabetic-induced kid-Bone morphogenic protein-7 (BMP-7), a n... more Conclusion. BMP-7 partially reversed diabetic-induced kid-Bone morphogenic protein-7 (BMP-7), a novel therapy for ney hypertrophy, restoring GFR, urine albumin excretion, and diabetic nephropathy. glomerular histology toward normal. Restoration of BMP-7 Background. Bone morphogenic protein-7 (BMP-7), an esexpression was associated with a successful repair reaction and sential developmental renal morphogen, is a secreted differena reversal of the ill-fated injury response. tiation factor of the adult collecting duct. It activates receptors in the collecting duct, distal nephron, proximal tubule, and glomerulus. BMP-7 is therapeutic in tubulointerstitial nephritis raising the question of broader efficacy in chronic kidney dis-Recent studies have made the surprising observation ease (CKD).

Research paper thumbnail of abacjournal article02 sep02 1

Research paper thumbnail of Analysis of ethylene signal-transduction kinetics associated with seedling-growth response and chitinase induction in wild-type and mutant arabidopsis

Plant Physiology, 1995

Kinetic aspects of ethylene-mediated signal transduction leading to seedlinggrowth inhibition and... more Kinetic aspects of ethylene-mediated signal transduction leading to seedlinggrowth inhibition and chitinase induction in Arabidopsis were investigated by the introduction of defined mutations in components of these pathways. Dose-response analysis of wild-type responses indicated that the rate-limiting steps for seedling responses and Arabidopsis basic-chitinase induction displayed Michaelis-Menten kinetics with apparent dissociation constants of the response (K,) of 0.1 and 1.4 pL 1-' ethylene, respectively. In the ethylene-insensitive efrl-l and ein2-32 mutant lines, both Arabidopsis basíc-chitinase induction and seedling-growth responses were completely disrupted, whereas the weaker efrl-2 allele eliminated the chitinase-induction response but only partially disrupted the seedling responses. A heterologous reporter gene containing the chitinase promoter from bean (bean basic-chitinase-/3-glucuronidase) displayed subsensitive kinetics (K, 120 pL L-' ethylene) compared to the response of the endogenous basic-chitinase response (K, 1.4 p L L-' ethylene). A model for ethylene signal transduction that accounts for the observed variations in ethylene dose-response relationships is presented. The relationship between the model and the biochemical mechanisms of well-characterized signal-transduction systems in animals is discussed.

Research paper thumbnail of Robust Quantization for Image Coding and Noisy Digital Transmission

A robust quantizer is developed for encoding a variety of memoryless sources and transmission ove... more A robust quantizer is developed for encoding a variety of memoryless sources and transmission over the binary symmetric channel (BSC). The system combines channel optimized scalar quantization (COSQ) with all-pass filtering, the latter performed using a binary phase-scrambling/descrambling method. Applied to a broad class of sources, the robust quantizer achieves the same performance as the Gaussian COSQ for the memoryless Gaussian source. This quantizer is used for image coding for transmission over a BSC. An explicit error protection code is used only to protect the side information. The PSNR performance degrades gracefully as the channel bit error rate increases

Research paper thumbnail of Image coding using robust quantization for noisy digital transmission

IEEE Transactions on Image Processing, 1998

A robust quantizer is developed for encoding memoryless sources and transmission over the binary ... more A robust quantizer is developed for encoding memoryless sources and transmission over the binary symmetric channel (BSC). The system combines channel optimized scalar quantization (COSQ) with all-pass filtering, the latter performed using a binary phase-scrambling/descrambling method. Applied to a broad class of sources, the robust quantizer achieves the same performance as the Gaussian COSQ for the memoryless Gaussian source. This quantizer is used in image coding for transmission over a BSC. The peak signal-to-noise ratio (PSNR) performance degrades gracefully as the channel bit error rate increases

Research paper thumbnail of Bone morphogenic protein-7 (BMP7), a novel therapy for diabetic nephropathy1

Kidney International, 2003

Conclusion. BMP-7 partially reversed diabetic-induced kid-Bone morphogenic protein-7 (BMP-7), a n... more Conclusion. BMP-7 partially reversed diabetic-induced kid-Bone morphogenic protein-7 (BMP-7), a novel therapy for ney hypertrophy, restoring GFR, urine albumin excretion, and diabetic nephropathy. glomerular histology toward normal. Restoration of BMP-7 Background. Bone morphogenic protein-7 (BMP-7), an esexpression was associated with a successful repair reaction and sential developmental renal morphogen, is a secreted differena reversal of the ill-fated injury response. tiation factor of the adult collecting duct. It activates receptors in the collecting duct, distal nephron, proximal tubule, and glomerulus. BMP-7 is therapeutic in tubulointerstitial nephritis raising the question of broader efficacy in chronic kidney dis-Recent studies have made the surprising observation ease (CKD).

Research paper thumbnail of abacjournal article02 sep02 1

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