A new state observer for active disturbance rejection control with measurement noise and output delay using the PDE-backstepping predictor.

This paper designs a new observer to address the issue of disturbance rejection in nonlinear plants with sense delay and measurement noise. The effect of sensor delay is characterized as a transport equation, and a predictor-based extended state observer has been designed using the PDE (partial differential equation) backstepping method. A cascaded ESO (extended state observer) architecture has been introduced to further reduce the limitation of measurement noise on observer bandwidth. This new cascade observer is capable of rapidly and accurately reconstructing system signals and compensating for output delay while avoiding the amplification of measurement noise. The numerical example has demonstrated the efficacy of the proposed observer structure, and extensive comparative experimental results have further confirmed its superiority.

Stereotactic body radiation therapy for non-small cell lung cancer using the non-coplanar radiation of Cyberknife and Varian linac.

PURPOSE: This study aims to evaluate the planned dose of stereotactic body radiation therapy (SBRT) for treating early peripheral non-small cell lung cancer (NSCLC) using the non-coplanar radiation from Cyberknife and Varian linac. Moreover, this study investigates whether Cyberknife and Varian linac are qualified for non-coplanar radiation SBRT for treating early peripheral NSCLC, and which one is better for protecting organs at risk (OARs). METHODS: Retrospective analysis was performed based on the Cyberknife radiation treatment plans (RTPs) and Varian Eclipse RTPs of 10 patients diagnosed with early peripheral NSCLC. The dose distributions in the target and OARs were compared between the RTPs of Cyberknife and Varian Eclipse using Mim medical imaging software. RESULTS: For PTV, no significant difference in D98 and D95 between the Cyberknife and Eclipse was observed (t = -0.35, -1.67, P > 0.05). The homogeneity indexes (HIs) of Cyberknife plans are higher (t = 71.86, P < 0.05) than those of Eclipse plans. The V10, V15, V20, V25, V30 and Dmean of the lung with NSCLC and the V20 of the whole lung for Cyberknife were less than those for Eclipse (t = -4.73, -5.62, -7.75, -6.38, -6.89, -3.14, -7.09, respectively, P < 0.05). Cyberknife plans have smaller spinal cord Dmax, trachea Dmax, heart Dmax, chest wall Dmax (t = -2.49, -2.57, -3.71, -3.56, respectively, P < 0.05) and esophagus Dmax (t = -1.95, P > 0.05) than Varian Eclipse plans. CONCLUSION: To fulfill SBRT by non-coplanar radiation, Cyberknife is recommended for the institutions equipped with Cyberknife, while Varian linac can be applied for the institutions that have not adopted Cyberknife in clinical radiotherapy yet.

Logic information communication in a fluorescent molecular switch.

Based on the chemical-sensitive fluorescence emission behaviors of the molecular switch 4-bromo-5-methoxy-2-(2-pyridyl)thiazole (2-BMPT), the communication of logic information between two functional units has been realized. With the rational control of the protonation and coordination reaction of 2-BMPT, an upstream switching unit (a 1:2 demultiplexer) and two downstream data-processing units are involved and interconnected in the communication. The two output states of the 1:2 demultiplexer serve as the initial input states of the two parallel downstream data-processing units, which execute the information communication between the two circuit layers. Furthermore, in the parallel data-processing layer, the logic gates of INHIBIT and YES accomplish their specific logic functions. Therefore, a molecular cascade circuit composed of an upstream switch and two downstream processing units has been constructed based on the chemical-modulated fluorescence properties of 2-BMPT.

Orientational organization of organic semiconductors within periodic nanoscale silica channels: modification of fluorophore photophysics through hierarchical self-assembly.

Smart nanomaterials: The orientational organization of small organic semiconductors (anthracene, in this case) within periodic nanoscale silica channels (see figure) is achieved through a novel hierarchical self-assembly approach. This elicits interesting optical effects and improved mechanical properties that could be of potential importance for functional materials.A novel hierarchical organic-inorganic self-assembly approach is proposed in driving the orientational organization of small organic semiconductors (anthracene, in this case). A cationic surfactant with the special organic semiconductor anthracene at the hydrophobic tail was synthesized and used as both the structure-directing agent and as functional nanobuilding blocks. The self-assembly procedure was rapid and allowed for the uniform and molecular-level controllable organization of the organic semiconductors within periodic nanoscale silica channels. A range of techniques were used to demonstrate that the photophysical and photochemical nature of anthracene is significantly altered in the inorganic host, consistent with orientational packing of the organic semiconductors and excimer formation within the channels, from which energy migration and significant emission occur. The nanocomposite has also been demonstrated to show an interesting selective sensor function with respect to small solvent molecules. We suggest that this method could be used to drive the assembly of a wide range of organic semiconductor guests, offering the development of a variety of useful, smart nanomaterials that are able to self-assemble in a controllable and robust fashion.