ABSTRACT
An α-diazodifluoroethane sulfonium reagent was developed in this study to undergo [3 + 2] radical cyclization with unactivated alkynes to give the corresponding 3-difluoromethyl pyrazoles under blue light irradiation conditions. The key to the success of this transformation lies in the formation of an electron donor-acceptor (EDA) complex between an electron-deficient α-diazo sulfonium salt and an electron-rich triaryl amine. This study circumvents a major substrate scope limitation in polar cycloaddition reactions of existent diazodifluoroethane reagents.
ABSTRACT
The miniature serpentine robot can be applied to NOTES (Natural Orifice Transluminal Endoscopic Surgery). In this paper, a bronchoscopy application is addressed. This paper describes the basic mechanical design and control scheme of this miniature serpentine robotic bronchoscopy. In addition, off-line backward path planning and real-time and in situ forward navigation in this miniature serpentine robot are discussed. The proposed backward-path-planning algorithm utilizes the 3D model of a bronchial tree constructed from the synthetization of medical images such as images from CT (Computed Tomography), MRI (Magnetic Resonance Imaging), or X-ray, to define a series of nodes/events backward from the destination, for example, the lesion, to the original starting point, for example, the oral cavity. Accordingly, forward navigation is designed to make sure this series of nodes/events shall be passed/occur from the origin to the destination. This combination of backward-path planning and forward navigation does not require accurate positioning information of the tip of the miniature serpentine robot, which is where the CMOS bronchoscope is located. Collaboratively, a virtual force is introduced to maintain the tip of the miniature serpentine robot at the center of the bronchi. Results show that this method of path planning and navigation of the miniature serpentine robot for bronchoscopy applications works.
