High temperatures have a great impact on plant reproductive development and subsequent fruit and seed set, but the underlying molecular mechanisms are not well understood. We used transcriptome ...profiling to investigate the effect of heat stress on reproductive development of Arabidopsis thaliana plants and observed distinct response patterns in vegetative versus reproductive tissues. Exposure to heat stress affected reproductive developmental programs, including early phases of anther/ovule development and meiosis. Also, genes participating in the unfolded protein response (UPR) were enriched in the reproductive tissue-specific genes that were upregulated by heat. Moreover, we found that the UPR-deficient bzip28 bzip60 double mutant was sensitive to heat stresses and had reduced silique length and fertility. Comparison of heat-responsive wild type versus bzip28 bzip60 plants identified 521 genes that were regulated by bZIP28 and bZIP60 upon heat stress during reproductive stages, most of which were noncanonical UPR genes. Chromatin immunoprecipitation coupled with high-throughput sequencing analyses revealed 133 likely direct targets of bZIP28 in Arabidopsis seedlings subjected to heat stress, including 27 genes that were also upregulated by heat during reproductive development. Our results provide important insights into heat responsiveness in Arabidopsis reproductive tissues and demonstrate the protective roles of the UPR for maintaining fertility upon heat stress.
In this brief, the control problem for flexible wings of a robotic aircraft is addressed by using boundary control schemes. Inspired by birds and bats, the wing with flexibility and articulation is ...modeled as a distributed parameter system described by hybrid partial differential equations and ordinary differential equations. Boundary control for both wing twist and bending is proposed on the original coupled dynamics, and bounded stability is proved by introducing a proper Lyapunov function. The effectiveness of the proposed control is verified by simulations.
Abstract
Distinguished from conventional ones, intelligent metasurfaces are endowed with three important characteristics: digitalization, programmability, and intelligence, which can be further ...integrated with detection, artificial neural networks, and feedback systems into a smart platform. Metasurface-based smart systems are expected to play an important role in wireless communications, advanced sensing technologies and artificial intelligence.
Abstract
Engineering the spectral response of composite materials in a broad range from ultraviolet to infrared can lead to a significant passive cooling functionality. This principle is applied to ...the design of a novel type of metafabric for cooling the human body under direct sunlight. Besides cooling effect, the metafabric features other merits including superior mechanical and wetting properties.
Holography has emerged as a vital approach to fully engineer the wavefronts of light since its invention dating back to the last century. However, the typically large pixel size, small field of view ...and limited space-bandwidth impose limitations in the on-demand high-performance applications, especially for three-dimensional displays and large-capacity data storage. Meanwhile, metasurfaces have shown great potential in controlling the propagation of light through the well-tailored scattering behavior of the constituent ultrathin planar elements with a high spatial resolution, making them suitable for holographic beam-shaping elements. Here, we review recent developments in the field of metasurface holography, from the classification of metasurfaces to the design strategies for both free-space and surface waves. By employing the concepts of holographic multiplexing, multiple information channels, such as wavelength, polarization state, spatial position and nonlinear frequency conversion, can be employed using metasurfaces. Meanwhile, the switchable metasurface holography by the integration of functional materials stimulates a gradual transition from passive to active elements. Importantly, the holography principle has become a universal and simple approach to solving inverse engineering problems for electromagnetic waves, thus allowing various related techniques to be achieved.
Abstract
Light projection displays play an increasingly important role in our modern life. Core projection systems including liquid crystal displays and digital micromirror devices can impose spatial ...light modulation and actively shape light waves. Recently, the advent of metasurfaces has revolutionized design concepts in nanophotonics, enabling a new family of optical elements with exceptional degrees of freedom. Here, we demonstrate a light projection display technology based on optical metasurfaces, called digital metasurface device (DMSD). Each metasurface pixel in a DMSD is electrically reconfigurable with well-controlled programmability and addressability. The DMSD can not only continuously modulate the intensity of light with high contrast, but also shape the wavefront of light generated by each metasurface pixel and dynamically switch between arbitrary holographic patterns. Our approach will pave an avenue towards the development of customized light projection devices. It will also drive the field of dynamic optical metasurfaces with fresh momentum and inspiring concepts.
It is known that resistance exercise using one limb can affect motor function of both the exercised limb and the unexercised contralateral limb, a phenomenon termed cross-education. It has been ...suggested that cross-education has clinical implications, e.g. in rehabilitation for orthopaedic conditions or post-stroke paresis. Much of the research on the contralateral effect of unilateral intervention on motor output is based on voluntary exercise. This scoping review aimed to map the characteristics of current literature on the cross-education caused by three most frequently utilised peripheral neuromuscular stimulation modalities in this context: electrical stimulation, mechanical vibration and percutaneous needling, that may direct future research and translate to clinical practice. A systematic search of relevant databases (Ebsco, ProQuest, PubMed, Scopus, Web of Science) through to the end of 2020 was conducted following the PRISMA Extension for Scoping Review. Empirical studies on human participants that applied a unilateral peripheral neuromuscular stimulation and assessed neuromuscular function of the stimulated and/or the unstimulated side were selected. By reading the full text, the demographic characteristics, context, design, methods and major findings of the studies were synthesised. The results found that 83 studies were eligible for the review, with the majority (53) utilised electrical stimulation whilst those applied vibration (18) or needling (12) were emerging. Although the contralateral effects appeared to be robust, only 31 studies claimed to be in the context of cross-education, and 25 investigated on clinical patients. The underlying mechanism for the contralateral effects induced by unilateral peripheral stimulation remains unclear. The findings suggest a need to enhance the awareness of cross-education caused by peripheral stimulation, to help improve the translation of theoretical concepts to clinical practice, and aid in developing well-designed clinical trials to determine the efficacy of cross-education therapies.
In this paper, a flexible cable with a payload attached at the bottom is considered to be the model of a crane system used for positioning the payload. The dynamics of the flexible cable coupled with ...the tip payload contribute to a hybrid system represented by partial-ordinary differential equations. An integral-barrier Lyapunov function (IBLF)-based control is proposed to suppress the undesirable vibrations of the flexible crane system with the boundary output constraint. Adaption laws are developed for handling parametric uncertainties. A novel IBLF is adopted to guarantee the uniform stability of the closed-loop systems without the violation of the boundary constraint. All closed-loop signals are ensured to be bounded. Extensive simulations are demonstrated to illustrate the performance of the control system.
Soil salinity is a widespread abiotic stress constraint threatening agricultural production, as it severely inhibits growth and development of crops. Several salt stress signaling pathways have been ...discovered in the model plant Arabidopsis thaliana, which include components for sensing the stress, transmitting the signal and regulating the downstream genes （Deinlein et al. 2o14; Julkowska and Testerink 2015）. In nature, plant roots directly encounter heterogeneous soils and therefore their responses to saline environments require dynamic changes in growth, a process in which plant cell walls play important roles （Tenhaken 2o15）. However, the molecular mechanisms underlying cell wall remodeling under stress conditions are still unclear.
Summary
Bruton tyrosine kinase (BTK), a mediator of B‐cell receptor (BCR) signalling, has been implicated in the pathogenesis of chronic lymphocytic leukaemia (CLL) and other B‐cell malignancies. ...Ibrutinib is an orally bioavailable and highly specific BTK inhibitor that was recently approved for treatment of patients with recurrent CLL and mantle cell lymphoma (MCL). In addition, ibrutinib has shown efficacy in subsets of patients with diffuse large B cell lymphoma (DLBCL) and Waldenstrom macroglobulinaemia (WM). However, despite ibrutinib's activity in multiple B‐cell malignancies, cases of primary and secondary resistance have emerged. The overall reported frequency of resistance is low, but follow‐up in many trials was short, and we predict that the incidence of observed resistance will increase as clinical use outside clinical trials expands over time. Mutations within BTK have been described and clearly interfere with drug binding; however, there are also emerging alternative mechanisms that bypass BTK entirely and offer new opportunities for other targeted agents. Improved understanding of mechanisms of primary and secondary resistance is essential to developing appropriate therapeutic strategies to both prevent and address resistance. This review provides a comprehensive analysis of ibrutinib resistance in CLL, MCL, DLBCL and WM and considers potential strategies for further study.
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