“Fata Morgana” or “Mirage” phenomena have long been captivated as optical illusions, which actually relies on gradient‐density air or vapor. Man‐made optical illusions have witnessed significant ...progress by resorting to artificially structured metamaterials. Nevertheless, two long‐standing challenges remain formidable: first, exotic parameters (negative or less than unity) become inevitable; second, the signature of original object is altered to that of a virtual counterpart. It is thus not able to address the holy grail of illusion per se, since a single virtual object still exposes the location. In this study, those problems are successfully addressed in a particular setup—illusion thermotics, which identically mimics the exterior thermal behavior of an equivalent reference and splits the interior original heat source into many virtual signatures. A general paradigm to design thermal illusion metadevices is proposed to manipulate thermal conduction, and empower robust simultaneous functions of moving, shaping, rotating, and splitting heat sources of arbitrary cross sections. The temperature profile inside the thermal metadevice can mislead the awareness of the real location, shape, size, and number of the actual heat sources. The present concept may trigger unprecedented development in other physical fields to realize multiple functionalized illusions in optics, electromagnetics, etc.
Existing optical/thermal illusions fail to address the holy grail of illusion per se, since a single virtual object still exposes the location. A solution to this problem is found in illusion thermotics, which identically mimics the exterior thermal behavior of an equivalent reference and splits the interior original heat source into many virtual signatures to enhance the deceptiveness unprecedentedly.
Chirality is a universal geometric property in both micro‐ and macroworlds. Recently, optical chiral effects have drawn increased attention due to their great potential in fundamental studies and ...practical applications. Significantly, the optical chiral response of artificial structures can be enhanced by orders of magnitude compared to that of their naturally occurring counterparts. These man‐made structures generally exhibit two types of optical chirality: extrinsic chirality and intrinsic chirality. The former relies on external illumination conditions, while the latter arises from the geometric characteristics of 3D objects. Herein, this review mainly focuses on the intrinsic chirality of artificial structures and discusses the existing realizations based on their design principles. In particular, an overview is given of the recent demonstrations of nonlinear optical effects in chiral structures and active chiral structures. Lastly, some promising prospects for future studies in the field are outlined.
3D metaphotonic structures with intrinsic chirality support both optical rotation and circular dichroism, which are orders of magnitude higher than that of their naturally occurring counterparts. They have drawn increased attention due to their potential in fundamental studies in physics, chemistry and biology, and in practical applications, such as negative refractive index media, molecule sensors, and modulators.
A White Random Laser Chang, Shu-Wei; Liao, Wei-Cheng; Liao, Yu-Ming ...
Scientific reports,
02/2018, Volume:
8, Issue:
1
Journal Article
Peer reviewed
Open access
Random laser with intrinsically uncomplicated fabrication processes, high spectral radiance, angle-free emission, and conformal onto freeform surfaces is in principle ideal for a variety of ...applications, ranging from lighting to identification systems. In this work, a white random laser (White-RL) with high-purity and high-stability is designed, fabricated, and demonstrated via the cost-effective materials (e.g., organic laser dyes) and simple methods (e.g., all-solution process and self-assembled structures). Notably, the wavelength, linewidth, and intensity of White-RL are nearly isotropic, nevertheless hard to be achieved in any conventional laser systems. Dynamically fine-tuning colour over a broad visible range is also feasible by on-chip integration of three free-standing monochromatic laser films with selective pumping scheme and appropriate colour balance. With these schematics, White-RL shows great potential and high application values in high-brightness illumination, full-field imaging, full-colour displays, visible-colour communications, and medical biosensing.
Amino acids are known regulators of cellular signaling and physiology, but how they are sensed intracellularly is not fully understood. Herein, we report that each aminoacyl-tRNA synthetase (ARS) ...senses its cognate amino acid sufficiency through catalyzing the formation of lysine aminoacylation (K-AA) on its specific substrate proteins. At physiologic levels, amino acids promote ARSs bound to their substrates and form K-AAs on the ɛ-amine of lysines in their substrates by producing reactive aminoacyl adenylates. The K-AA marks can be removed by deacetylases, such as SIRT1 and SIRT3, employing the same mechanism as that involved in deacetylation. These dynamically regulated K-AAs transduce signals of their respective amino acids. Reversible leucylation on ras-related GTP-binding protein A/B regulates activity of the mammalian target of rapamycin complex 1. Glutaminylation on apoptosis signal-regulating kinase 1 suppresses apoptosis. We discovered non-canonical functions of ARSs and revealed systematic and functional amino acid sensing and signal transduction networks.
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•Amino acids modify ɛ-amines of lysines•Each tRNA synthetase is the aminoacyl transferase of its cognate amino acid•Aminoacylations can be reversed by deacetylases•Aminoacylations transmit amino acid signals to regulate cellular functions
He et al. reveal that tRNA synthetases sense sufficiency of amino acids and act as aminoacyl transferases to modify ɛ-amines of lysines in proteins, with leucylation of RagA/B regulating mTORC1 activity and glutaminylation of ASK1 inhibiting apoptosis. Lysine aminoacylation marks are removed by SIRT1 and SIRT3.
By modulating physical characteristics (amplitude, phase, polarization, etc.) at the subwavelength scale, metasurfaces have shown prominence in controlling electromagnetic waves. However, ...metasurfaces with linear phase distributions face difficulties in various wavefront reconstructions intentionally and efficiently, and complex‐amplitude metasurfaces with independent amplitude and phase modulations are preferable. Here, a new scheme of the reprogrammable nonlinearly‐phased grating metasurface, comparable to complex‐amplitude metasurfaces, enabling real‐time and versatile control of multiple spatial harmonics by modulating the phase is reported. Through elaborate and instantaneous programming of nonlinear phase distributions at the metasurface interface, desired electromagnetic wavefronts can be reconstructed in real‐time by reconfiguring the generation and suppression of multiple spatial harmonics and by customizing reflection angles and reflection intensities of each spatial harmonic. To corroborate this design, generation and suppression, intensity tailoring, and retro‐reflection of multiple spatial harmonics are presented and verified experimentally. This work provides a real‐time and efficient way to implement dynamical reconstruction of various electromagnetic wavefronts and can be further applied to other potential scenarios such as holography, imaging, and wireless communication.
A reprogrammable nonlinearly‐phased grating metasurface is proposed for the real‐time and efficient reconstruction of versatile electromagnetic wavefronts. Profiting from elaborate and instantaneous reprogramming of nonlinear phase distributions at the metasurface interface, the incident waves can be reflected as multiple spatial harmonics with customized characteristics. Such metasurfaces may facilitate more advanced and facile electromagnetic platforms.
In this study the authors used an unusual linear symmetric poly(ethylene oxide‐b‐caprolactone) (PEO‐b‐PCL) diblock copolymer as a template within phenolic/double‐decker silsesquioxane (DDSQ) hybrids ...to synthesize mesoporous phenolic/DDSQ materials having Frank–Kasper (FK) phases (e.g., σ, A15, H, and Z phases). These FK structures are the first to have been prepared using a block copolymer and the first to exist in mesoporous materials. The authors' mesoporous carbon/DDSQ hybrids displayed high capacitance (764 F g−1 at a current of 0.5 A g−1 and 98.4% capacitance retention over 2000 cycles), arising from their high surface areas, high pore volumes, and tunable concentrations of N, O, and Si heteroatoms.
Mesoporous Frank–Kasper Phase: Unusual linear symmetric PEO‐b‐PCL diblock copolymer as the template into PDDSQ hybrids to synthesize the mesoporous phenolic/DDSQ materials with Frank‐Kasper phases, such as σ, A15, H, and Z phases, can act as the first example to both the block copolymer and mesoporous materials fields.
Summary
Plant protoplasts are useful for assessing the efficiency of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR‐associated protein 9 (Cas9) mutagenesis. We improved the ...process of protoplast isolation and transfection of several plant species. We also developed a method to isolate and regenerate single mutagenized Nicotianna tabacum protoplasts into mature plants. Following transfection of protoplasts with constructs encoding Cas9 and sgRNAs, target gene DNA could be amplified for further analysis to determine mutagenesis efficiency. We investigated N. tabacum protoplasts and derived regenerated plants for targeted mutagenesis of the phytoene desaturase (NtPDS) gene. Genotyping of albino regenerants indicated that all four NtPDS alleles were mutated in amphidiploid tobacco, and no Cas9 DNA could be detected in most regenerated plants.
The dynamic cell–cell communication is essential for tissue homeostasis in normal physiological circumstances and contributes to a diversified tumor microenvironment. Although exosomes are ...extracellular vesicles that actively participate in cell–cell interaction by shutting cellular components, impacts of tumor exosomes in the context of cancer stemness remain elusive. Here, we expand colorectal cancer stem cells (CRCSCs) as cancer spheroids and demonstrate that the β‐catenin/Tcf‐4‐activated RAB27B expression is required for the secretion of CRCSC exosomes. In an exosomal RNA sequencing analysis, a switch of exosomal RNA species from retrotransposons to microRNAs (miRNAs) is identified upon expanding CRCSCs. miRNA‐146a‐5p (miR‐146a) is the major miRNA in CRCSC exosomes and exosomal miR‐146a promotes stem‐like properties and tumorigenicity by targeting Numb in recipient CRC cells. Among 53 CRC patients, those with abundant exosomal miR‐146a expression in serum exhibits higher miR‐146aHigh/NumbLow CRCSC traits, an increased number of tumor‐filtrating CD66(+) neutrophils and a decreased number of tumor‐infiltrating CD8(+) T cells. Our study elucidates a unique mechanism of tumor exosome‐mediated stemness expansion.
What's new?
The tumor microenvironment (TME) is composed of heterogeneous tumor cells and host cells interacting with each other to promote disease progression. However, diagnostic and prognostic biomarkers to monitor the cancer stem cells (CSCs)‐host interplay are lacking. Here, the authors explore the role of tumor exosomes in cancer stemness and demonstrate that RAB27B‐assisted secretion of miRNA‐dominant exosomes is one critical feature of CSCs. Importantly, they show that colorectal cancer stem cells release miR‐146a‐loaded oncogenic exosomes for reprogramming non‐CSC cells and demonstrate the clinical relevance of exosomal miR‐146a in predicting the TME of CRC patients.
Geometric metasurfaces primarily follow the physical mechanism of Pancharatnam–Berry (PB) phases, empowering wavefront control of cross‐polarized reflective/transmissive light components. However, ...inherently accompanying the cross‐polarized components, the copolarized output components have not been attempted in parallel in existing works. Here, a general method is proposed to construct phase‐modulated metasurfaces for implementing functionalities separately in co‐ and cross‐polarized output fields under circularly polarized (CP) incidence, which is impossible to achieve with solely a geometric phase. By introducing a propagation phase as an additional degree of freedom, the electromagnetic (EM) energy carried by co‐ and cross‐polarized transmitted fields can be fully phase‐modulated with independent wavefronts. Under one CP incidence, a metasurface for separate functionalities with controllable energy repartition is verified by simulations and proof‐of‐principle microwave experiments. A variety of applications can be readily expected in spin‐selective optics, spin‐Hall metasurfaces, and multitasked metasurfaces operating in both reflective and transmissive modes.
A general scheme based on a phase‐modulated metasurface for simultaneous and independent manipulation of co‐ and cross‐polarized wavefronts is proposed, which breaks through the inherent limitation of the geometric phase principle and achieves full energy modulation in output fields. The energy proportion between two orthogonal CP output functionalities can also be artificially manipulated as an extra freedom of degree for light manipulation.
Autoencoder for words Liou, Cheng-Yuan; Cheng, Wei-Chen; Liou, Jiun-Wei ...
Neurocomputing (Amsterdam),
09/2014, Volume:
139
Journal Article, Conference Proceeding
Peer reviewed
This paper presents a training method that encodes each word into a different vector in semantic space and its relation to low entropy coding. Elman network is employed in the method to process word ...sequences from literary works. The trained codes possess reduced entropy and are used in ranking, indexing, and categorizing literary works. A modification of the method to train the multi-vector for each polysemous word is also presented where each vector represents a different meaning of its word. These multiple vectors can accommodate several different meanings of their word. This method is applied to the stylish analyses of two Chinese novels, Dream of the Red Chamber and Romance of the Three Kingdoms.
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