Novel fluorescent organic soft porous crystals have been designed and prepared based on a multisubstituted silole bearing 1-phenyl-2,2-dicyanoethene moieties (molecule 8). 8 exhibited a series of emission colors, ranging from yellow to dark red with an over 70 nm shift of emission maximum. Molecule 8 also showed the ability to reversibly switch between different solid states, and a typical mechanofluorochromism was observed by cyclic operation of the grinding-heating-cooling processes. In addition, two single crystals (O and R) were successfully obtained in proper conditions, and the crystallographic data indicated that crystal O and R had reasonable hollow structures, inside which different solvent molecules were selectively encapsulated. More importantly, we have presented a proof-of-concept example of the strategy for the designation of organic soft porous crystals with a conjugated fluorophore and demonstrated the successful achievement of softness, porosity and crystallization ability. This design strategy is instructive to design and construct organic soft porous crystals with other conjugated building blocks and develop novel smart and stimuli-responsive photo/ electronic materials.

Transmissions of plant viruses between individuals of their vector insects through mating are rare events. Recently, three begomoviruses were found to be transmitted between males and females of the whitefly Bemisia tabaci through mating, and two viruses were shown to be transmitted transovarially to progeny. However, results between reports were not consistent. Here we examined the horizontal and vertical transmission of Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl China virus (TYLCCNV) by the B and Q biotypes of B. tabaci, using virus isolates and whitefly colonies established recently in China. Both TYLCV DNA and TYLCCNV DNA were shown to be transmitted horizontally and vertically by each of the two biotypes of the whitefly, but frequency of transmission was usually low. In transovarial transmission, virus DNA was detected in eggs and nymphs but not in the adults of the first generation progeny, except in the combination of TYLCV and Q biotype whitefly where 2–3% of the offspring adults contained the virus DNA. We also showed that the first generation adults, which developed from eggs of viruliferous whiteflies, were not infective to plants. These results demonstrated that for the viruses and whiteflies tested here low frequency of horizontal and vertical transmission can be expected but these two modes of transmission are unlikely to have much epidemiological relevance in the field.

A voltage-controlled tunable phase shifter is introduced in the architecture of a microwave Doppler radar to eliminate the null point problem in the non-contact vital sign detection. With a simple control mechanism, the phase of the demodulated signal can be effectively adjusted, providing an opportunity to always lock the radar system to the optimum point. Experiment demonstrates that such a method results in a significant improvement in measurement accuracy.Introduction: Since the early 1970s, microwave continuous-wave Doppler radar (CWDR) has been widely used or studied in various wireless motion sensing applications, such as vital sign detection [1, 2], disaster rescuing [3], and wireless measurement of periodic mechanical movements [4]. A lot of progress has been achieved in this area. However, there is still a challenge to provide a robust system, the detection accuracy of which is insensitive to target position, because of the null point issue. Null points occur in the CWDR system when the received signal and local oscillator (LO) are either in-phase or 1808 out of phase, which would severely decrease detection accuracy [3], especially for systems using very short wavelengths. Researches aiming to solve the null point problem have been conducted for years. In [3], channel selection is proposed by utilising quadrature Doppler radar architecture. By doing so, the null point problem can be eliminated by properly choosing the channel that is not at a null point. However, the detection accuracy is not always satisfactory because whether the system can work at an optimum point still depends on the target position. In [5], frequency tuning based on double-sideband transmission was proposed. However, it requires a two-stage downconversion structure with a tunable intermediate frequency, which increases the hardware complexity. In [6], an arctangent demodulation with DC offset compensation is proposed. However, system calibration is required before each measurement, which brings inconvenience to the continuous detection. In this Letter, we propose a simple but novel method to systematically overcome the null point problem. By introducing a voltage-controlled RF phase shifter to the CWDR, the null point problem can be eliminated. Moreover, the transceiver is always able to work at the optimum point when an adaptive phase control loop can be properly established. An experiment has been conducted and theoretical analysis is clearly verified.

In this paper, we study the Cauchy problem to a chemotaxis-haptotaxis model describing cancer invasion in $\mathbb{R}^{2}$. The main feature is to prove that $8\pi$ is the critical mass on initial data for distinguishing existence and blow-up of solutions to the model. Namely, when the initial mass is less than $8\pi$, we prove global existence of solutions by constructing a proper free energy and using the Brezis-Merle type inequality. On the contrary, the finite time blow-up of solutions may occur if the initial mass is greater than $8\pi$ and the initial second moment is small enough. Comparing to the classical Keller-Segel model, we find that the haptotaxis has no effect on the critical mass of the model.