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| 2. |
- Li, Xiaohui, et al.
(författare)
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Sensitive label-free and compact biosensor based on concentric silicon-on-insulator microring resonators
- 2009
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Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 48:25, s. F90-F94
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Tidskriftsartikel (refereegranskat)abstract
- We propose an ultracompact parallel label-free biosensor based on concentric silicon-on-insulator microring resonators. Our numerical studies show that the proposed biosensor offers higher sensitivity and a larger detection area than conventional single-ring-based sensors. We analyze the detection sensitivity of the DNA hybridization by immobilizing the probe on top of the double concentric ring resonators and in the ring-ring air gap. For a concentric double-ring system with an area of 27: 646 mu m(2), the bulk detection sensitivity is 683 nm RIU-1. The sensitive uniformity of the system related to the optical field distribution is also studied.
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| 3. |
- Liu, Fangfei, et al.
(författare)
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Compact optical temporal differentiator based on silicon microring resonator
- 2008
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Ingår i: Optics Express. - 1094-4087. ; 16:20, s. 15880-15886
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Tidskriftsartikel (refereegranskat)abstract
- We propose and experimentally demonstrate a temporal differentiator in optical field based on a silicon microring resonator with a radius of 40 mu m. The microring resonator operates near the critical coupling region, and can take the first order derivative of the optical field. It features compact size thus is suitable for integration with silicon-on-insulator (SOI) based optical and electronic devices. The performance of this optical differentiator is tested using signals with typical shapes such as Gaussian, sinusoidal and square-like pulses at data rates of 10 Gb/s and 5 Gb/s.
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| 4. |
- Maurer, Matthew, et al.
(författare)
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3-Phosphoinositide-dependent kinase 1 potentiates upstream lesions on the phosphatidylinositol 3-kinase pathway in breast carcinoma
- 2009
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Ingår i: Cancer Research. - 1538-7445. ; 69:15, s. 306-6299
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Tidskriftsartikel (refereegranskat)abstract
- Lesions of ERBB2, PTEN, and PIK3CA activate the phosphatidylinositol 3-kinase (PI3K) pathway during cancer development by increasing levels of phosphatidylinositol-3,4,5-triphosphate (PIP(3)). 3-Phosphoinositide-dependent kinase 1 (PDK1) is the first node of the PI3K signal output and is required for activation of AKT. PIP(3) recruits PDK1 and AKT to the cell membrane through interactions with their pleckstrin homology domains, allowing PDK1 to activate AKT by phosphorylating it at residue threonine-308. We show that total PDK1 protein and mRNA were overexpressed in a majority of human breast cancers and that 21% of tumors had five or more copies of the gene encoding PDK1, PDPK1. We found that increased PDPK1 copy number was associated with upstream pathway lesions (ERBB2 amplification, PTEN loss, or PIK3CA mutation), as well as patient survival. Examination of an independent set of breast cancers and tumor cell lines derived from multiple forms of human cancers also found increased PDK1 protein levels associated with such upstream pathway lesions. In human mammary cells, PDK1 enhanced the ability of upstream lesions to signal to AKT, stimulate cell growth and migration, and rendered cells more resistant to PDK1 and PI3K inhibition. After orthotopic transplantation, PDK1 overexpression was not oncogenic but dramatically enhanced the ability of ERBB2 to form tumors. Our studies argue that PDK1 overexpression and increased PDPK1 copy number are common occurrences in cancer that potentiate the oncogenic effect of upstream lesions on the PI3K pathway. Therefore, we conclude that alteration of PDK1 is a critical component of oncogenic PI3K signaling in breast cancer.
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| 5. |
- Wang, Tao, et al.
(författare)
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Modeling of quasi-grating sidewall corrugation in SOI microring add-drop filters
- 2009
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Ingår i: Optics Communications. - : Elsevier BV. - 0030-4018 .- 1873-0310. ; 282:17, s. 3464-3467
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Tidskriftsartikel (refereegranskat)abstract
- We build a model to study the sidewall corrugation of fabricated silicon microrings and investigate its impact on the spectral response of the resonator system. From the scanning electron microscope images, the sidewall corrugation can be engineered into certain periodicity and characterized into a group of rectangular gratings, or quasi-gratings, which in turn generate mutual mode coupling between the forward- and backward-propagating modes in the ring and lead to resonance splitting. We find that the reflectivity of the quasi-gratings is proportional to the mutual coupling strength and the resonance splitting only occurs at the resonances where high reflectivity takes place. The model agrees well with the experimental measurements and provides some guideline in applying mutual mode coupling for various functions in the field of optics.
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| 6. |
- Wang, Tao, et al.
(författare)
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Pulse Delay and Advancement in SOI Microring Resonators With Mutual Mode Coupling
- 2009
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 27:21, s. 4734-4743
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we experimentally demonstrate continuously tunable pulse propagation in SOI microring resonators with mutual mode coupling, which is induced by nanosized gratings along the ring sidewalls. In the presence of the mutual mode coupling, dispersion-induced group delay is investigated in single-waveguide and double-waveguide coupled single-ring resonators, respectively. In particular, pulse propagation in the drop channel of a double-waveguide coupled resonator is observed and exhibits continuously tunable delay and advancement features in the experiment. Delayed pulses are also obtained at the reflection port of a single-waveguide coupled resonator due to the existence of backward whispering gallery mode (WGM).
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