ABSTRACT Focusing and defocusing dynamics of weak-light ring-shaped beams in a Λ-type atomic syst... more ABSTRACT Focusing and defocusing dynamics of weak-light ring-shaped beams in a Λ-type atomic system are investigated. It is found that focusing of weak light is possible due to the quantum interference effect. The focusing or defocusing regime with vanishing absorption can be manipulated by adjusting detunings from the resonant transition. When the fields are tuned appropriately larger than resonant frequencies, the beam propagates in the defocusing regime and diffraction of the beam takes place. Conversely, the beam focuses in the medium when the laser frequencies are tuned smaller than the resonant frequencies.
Purpose Low-dose metronomic (LDM) chemotherapy represents a new strategy to treat solid tumors by... more Purpose Low-dose metronomic (LDM) chemotherapy represents a new strategy to treat solid tumors by stronger antiangiogenic activity and less side effects. The aim of the study is to rationally develop a docetaxel metronomic regimen in preclinical settings of gastric cancer. Methods In vitro cell proliferation, apoptosis, and thrombospondin-1/vascular endothelial growth factor (TSP-1/VEGF) expression analyses were performed on human umbilical vein endothelial cells (HUVECs) and gastric cancer (BGC-823) cells exposed for 144 h to metronomic concentrations of docetaxel. BGC-823 human gastric cancer xenograft model was used, and tumor growth and side effects were closely monitored. Quantitative real-time PCR was used to determine TSP-1/VEGF mRNA levels in tumor samples. Expression of VEGF and CD31 was observed by immunohistochemistry. Results Our results indicated that LDM docetaxel preferentially inhibited HUVEC cell proliferation and induced HUVEC apoptosis. Docetaxel significantly increased TSP-1 expression and secretion in HUVEC cells whereas the expression and secretion of VEGF significantly decreased in BGC-823 cells. LDM docetaxel significantly inhibited BGC-823 tumor growth in the absence of toxicity, which was accompanied by decreases in microvessel density (MVD) and VEGF and increases in TSP-1 gene expression in tumor tissues. Conclusions In vitro results show the antiangiogenic properties of LDM docetaxel. In vivo, LDM docetaxel treatment is effective against gastric tumor and microvessel growth without toxic effect on nude mice.
The most important goal of virtual reality is to create a virtual world by computers where users ... more The most important goal of virtual reality is to create a virtual world by computers where users are allowed to view the environment and control the virtual objects interactively. Traditionally, virtual reality systems use 3D computer graphics to model and render a virtual environment in real time. However, this approach usually requires laborious modeling and expensive special-purpose rendering hardware. Image-based rendering is a new approach in composing a virtual environment in which a set of panoramic images is used to compose the virtual environment and walking in the space is accomplished by “hopping” to different panoramic points. This paper introduces an experimental image-based VR system. The techniques utilized in the system, in particular the authoring and interactive control tools of the system, are described in detail.
ABSTRACT Focusing and defocusing dynamics of weak-light ring-shaped beams in a Λ-type atomic syst... more ABSTRACT Focusing and defocusing dynamics of weak-light ring-shaped beams in a Λ-type atomic system are investigated. It is found that focusing of weak light is possible due to the quantum interference effect. The focusing or defocusing regime with vanishing absorption can be manipulated by adjusting detunings from the resonant transition. When the fields are tuned appropriately larger than resonant frequencies, the beam propagates in the defocusing regime and diffraction of the beam takes place. Conversely, the beam focuses in the medium when the laser frequencies are tuned smaller than the resonant frequencies.
Purpose Low-dose metronomic (LDM) chemotherapy represents a new strategy to treat solid tumors by... more Purpose Low-dose metronomic (LDM) chemotherapy represents a new strategy to treat solid tumors by stronger antiangiogenic activity and less side effects. The aim of the study is to rationally develop a docetaxel metronomic regimen in preclinical settings of gastric cancer. Methods In vitro cell proliferation, apoptosis, and thrombospondin-1/vascular endothelial growth factor (TSP-1/VEGF) expression analyses were performed on human umbilical vein endothelial cells (HUVECs) and gastric cancer (BGC-823) cells exposed for 144 h to metronomic concentrations of docetaxel. BGC-823 human gastric cancer xenograft model was used, and tumor growth and side effects were closely monitored. Quantitative real-time PCR was used to determine TSP-1/VEGF mRNA levels in tumor samples. Expression of VEGF and CD31 was observed by immunohistochemistry. Results Our results indicated that LDM docetaxel preferentially inhibited HUVEC cell proliferation and induced HUVEC apoptosis. Docetaxel significantly increased TSP-1 expression and secretion in HUVEC cells whereas the expression and secretion of VEGF significantly decreased in BGC-823 cells. LDM docetaxel significantly inhibited BGC-823 tumor growth in the absence of toxicity, which was accompanied by decreases in microvessel density (MVD) and VEGF and increases in TSP-1 gene expression in tumor tissues. Conclusions In vitro results show the antiangiogenic properties of LDM docetaxel. In vivo, LDM docetaxel treatment is effective against gastric tumor and microvessel growth without toxic effect on nude mice.
The most important goal of virtual reality is to create a virtual world by computers where users ... more The most important goal of virtual reality is to create a virtual world by computers where users are allowed to view the environment and control the virtual objects interactively. Traditionally, virtual reality systems use 3D computer graphics to model and render a virtual environment in real time. However, this approach usually requires laborious modeling and expensive special-purpose rendering hardware. Image-based rendering is a new approach in composing a virtual environment in which a set of panoramic images is used to compose the virtual environment and walking in the space is accomplished by “hopping” to different panoramic points. This paper introduces an experimental image-based VR system. The techniques utilized in the system, in particular the authoring and interactive control tools of the system, are described in detail.
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