An enantioselective intramolecular allylic C-H oxidation to generate optically active chromans has been accomplished under the cooperative catalysis of a palladium complex of chiral phosphoramidite ligand and 2-fluorobenzoic acid. Mechanistic studies suggest that this reaction commences with a Pd-catalyzed allylic C-H activation event and then undergoes asymmetric allylic alkoxylation. The synthetic significance of the method has been embodied by concisely building up a key chiral intermediate to access (+)-diversonol.

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A wearable surgical navigation system is developed for intraoperative imaging of surgical margin in cancer resection surgery. The system consists of an excitation light source, a monochromatic CCD camera, a host computer, and a wearable headset unit in either of the following two modes: head-mounted display (HMD) and Google glass. In the HMD mode, a CMOS camera is installed on a personal cinema system to capture the surgical scene in real-time and transmit the image to the host computer through a USB port. In the Google glass mode, a wireless connection is established between the glass and the host computer for image acquisition and data transport tasks. A software program is written in Python to call OpenCV functions for image calibration, co-registration, fusion, and display with augmented reality. The imaging performance of the surgical navigation system is characterized in a tumor simulating phantom. Image-guided surgical resection is demonstrated in an ex vivo tissue model. Surgical margins identified by the wearable navigation system are co-incident with those acquired by a standard small animal imaging system, indicating the technical feasibility for intraoperative surgical margin detection. The proposed surgical navigation system combines the sensitivity and specificity of a fluorescence imaging system and the mobility of a wearable goggle. It can be potentially used by a surgeon to identify the residual tumor foci and reduce the risk of recurrent diseases without interfering with the regular resection procedure.

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Purpose – The purpose of this paper is to examine the effects of transformational school leadership on teachers’ commitment to change and the effects of organizational and teachers’ factors on teachers’ perception of transformational school leadership in the Chinese urban upper secondary school context. Design/methodology/approach – The paper mainly uses quantitative methods to explore the relationships between different constructs. The author asks: to what extent can transformational school leadership practices in the urban upper secondary schools of a particular Chinese city explain the variation in teachers’ commitment to change during curriculum reform? What are the effects of organizational and teachers’ factors on teachers’ perceptions of transformational school leadership? Findings – The results of multiple regression analysis showed that the effect of transformational school leadership was moderate when transformational school leadership and teachers’ commitment to change were treated as single variables. Four dimensions of transformational leadership practice together explained the moderate effects on four dimensions of teachers’ commitment to change, among which the effect of managing the instructional program was the most prominent. The results of multiple regression analysis also revealed that variables like culture, strategy, environment, and teachers’ age had significant relationships with teachers’ perceptions of transformational school leadership. Culture, environment, strategy, structure, and teachers’ factors such as age and grade taught had moderate effects on different dimensions of teachers’ perceptions of transformational school leadership. Originality/value – This study is one of the first to explore the effects of transformational school leadership on teachers’ commitment to change in the Chinese urban upper secondary school context. The findings contribute to educational management in China and similar contexts, and this study advances knowledge and furthers the understandings of the transferability of theories to different contexts.

In the process of teaching and learning activity, teachers' language plays a very important role in EFL classroom, such as teachers' academic instructions, motivating the class and evaluating students. No exaggeration to say that teachers' language is indispensable to effective communication in class. Adopting Brown and Levinson's politeness strategies through class observation, the researcher aims to reveal how the teacher applies politeness strategies to his teaching practice in the language use. Through analyzing the data collected, the researcher finds out the college teacher conducts his class on term of positive politeness and negative politeness in a practical way. Evidently the adoption of politeness strategies shortens the teacher-student social distance, makes the class interesting, and in turn facilitates English teaching and learning.

The amphibious robot is so attractive and challenging for its broad application and its complex working environment. It should walk on rough ground, maneuver underwater and pass through transitional terrain such as sand and mud, simultaneously. To tackle with such a complex task, a novel amphibious robot (AmphiHex-I) with transformable leg-flipper composite propulsion is proposed and developed. This paper presents the detailed structure design of the transformable leg-flipper propulsion mechanism and its drive module, which enables the amphibious robot passing through the terrain, water and transitional zone between them. A preliminary theoretical analysis is conducted to study the interaction between the elliptic leg and transitional environment such as granular medium. An orthogonal experiment is designed to study the leg locomotion in the sandy and muddy terrain with different water content. Finally, basic propulsion experiments of AmphiHex-I are launched, which verified the locomotion capability on land and underwater is achieved by the transformable leg-flipper mechanism.

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