New 6,13-bis1'-(C≡C)-2'-R-1',2'-C2B10H10pentacenes (R = H, Me, Et, n-Bu) are synthesized and fully characterized. The results show that the alkyl substituents on the second cage carbon have a ...significant impact on the molecular packing, and the incorporation of the o-carboranyl moiety into a π conjugated system can lower both LUMO and HOMO energy levels, converting a typical p-type semiconductor into an ambipolar one.
Achieving adaptive behavior in artificial systems, analogous to living organisms, has been a long-standing goal in electronics and materials science. Efforts to integrate adaptive capabilities into ...synthetic electronics traditionally involved a typical architecture comprising of sensors, an external controller, and actuators constructed from multiple materials. However, challenges arise when attempting to unite these three components into a single entity capable of independently coping with dynamic environments. Here, we unveil an adaptive electronic unit based on a liquid crystal polymer that seamlessly incorporates sensing, signal processing, and actuating functionalities. The polymer forms a film that undergoes anisotropic deformations when exposed to a minor heat pulse generated by human touch. We integrate this property into an electric circuit to facilitate switching. We showcase the concept by creating an interactive system that features distributed information processing including feedback loops and enabling cascading signal transmission across multiple adaptive units. This system responds progressively, in a multi-layered cascade to a dynamic change in its environment. The incorporation of adaptive capabilities into a single piece of responsive material holds immense potential for expediting progress in next-generation flexible electronics, soft robotics, and swarm intelligence.
An exploratory study on novel silylethynylated N‐heteropentacenes, which have their N atoms on the terminal rings of the pentacene backbone, is reported. This study leads to both p‐ and n‐channel ...organic thin‐film transistors with high field‐effect mobility and also reveals that the position of the N atoms plays an important role in tuning the structures and properties of organic semiconductors based on N‐heteropentacenes.
This study presents a new class of conjugated polycyclic molecules that contain seven‐membered rings, detailing their synthesis, crystal structures and semiconductor properties. These molecules have ...a nearly flat C6‐C7‐C6‐C7‐C6 polycyclic framework with a p‐quinodimethane core. With field‐effect mobilities of up to 0.76 cm2 V−1 s−1 as measured from solution‐processed thin‐film transistors, these molecules are alternatives to the well‐studied pentacene analogues for applications in organic electronic devices.
All sixes and sevens: A new class of conjugated polycyclic molecules have a nearly flat C6‐C7‐C6‐C7‐C6 polycyclic framework with a p‐quinodimethane core. With a field‐effect mobility of up to 0.76 cm2 V−1 s−1 as measured from solution‐processed thin‐film transistors, these molecules are alternatives to the pentacene analogues for application in organic electronic devices.
Coatings with a dynamic surface topography are of interest for applications in haptics, soft robotics, cell growth in biology, hydro- and air dynamics and tribology. Here we propose a design for ...creating oscillating surface topographies in thin liquid crystal polymer network coatings under an electric field. By applying an alternating electric field, the coating surface deforms, and pre-designed local corrugations appear. The continuous AC electric field further initiates oscillations superimposed on the formed topographies. This effect is based on microscopic free volume creation. By exciting the liquid crystal network at its resonance frequency, maximum free volume is generated and large surface topographies are formed. Molecular simulation is used to examine this behaviour in microscopic detail as a function of oscillation frequency. Surface topography formation is fast and reversible. Excess free volume is energetically unfavourable, thus the surface topographies disappear within seconds once the electric field is removed.
Abstract
Overcoming the sluggish kinetics of alkaline hydrogen oxidation reaction (HOR) is challenging but is of critical importance for practical anion exchange membrane fuel cells. Herein, abundant ...and efficient interfacial active sites are created on ruthenium (Ru) nanoparticles by anchoring atomically isolated chromium coordinated with hydroxyl clusters (Cr
1
(OH)
x
) for accelerated alkaline HOR. This catalyst system delivers 50-fold enhanced HOR activity with excellent durability and CO anti-poisoning ability via switching the active sites from Ru surface to Cr
1
(OH)
x
-Ru interface. Fundamentally different from the conventional mechanism merely focusing on surface metal sites, the isolated Cr
1
(OH)
x
could provide unique oxygen species for accelerating hydrogen or CO spillover from Ru to Cr
1
(OH)
x
. Furthermore, the original oxygen species from Cr
1
(OH)
x
are confirmed to participate in hydrogen oxidation and H
2
O formation. The incorporation of such atomically isolated metal hydroxide clusters in heterostructured catalysts opens up new opportunities for rationally designing advanced electrocatalysts for HOR and other complex electrochemical reactions. This work also highlights the importance of size effect of co-catalysts, which should also be paid substantial attention to in the catalysis field.
Chemiluminescence-based bioassays have become increasingly important in clinical, pharmaceutical, environmental, and food safety fields owing to their high sensitivity, wide linear range, and simple ...instrumentation. During the past decade, it has been found that metal nanoparticles can initiate various liquid-phase chemiluminescence reactions as catalysts, reductants, energy acceptors, and nanosized reaction platforms owing to their unique optical, catalytic, and surface properties and chemical reactivity, which are very important for chemiluminescence bioassays based on metal nanoparticles as nanoprobes or a nanointerface. In this article, we summarize recent progress in metal-nanoparticle-initiated liquid-phase chemiluminescence, including reaction systems, mechanisms, and their applications in chemiluminescence-based bioassays, especially for immunoassays, DNA assays, aptamer-based assays, high-performance liquid chromatography or capillary electrophoresis analysis, and flow injection analysis.
Figure
Comprehensive summary of metal nanoparticle (NP)-involved chemiluminescence (CL) systems and their applications. CE capillary electrophoresis, HPLC highperformance liquid chromatography
•Most of the Archean mafic lower crust has not delaminated and is preserved globally.•<2.5 Ga zircon ages in xenoliths is not a criterion for inferring post-Archean underplating.•The quantity of ...Archean rocks in the lower crust may be much greater than that exposed.
Mafic granulite xenoliths found in Archean cratons have generally been inferred to form from post-Archean basaltic underplating, implying that the Archean mafic lower crust was removed perhaps via delamination. Here based on an integrated study of granulite terrain, granulite xenoliths and lower crustal-derived granitoids, we make a compelling case that most of the Tertiary alkali basalt-entrained mafic granulite xenoliths from the northern North China craton are restites left after partial melting of the late Archean mafic lower crust to produce the Mesozoic granitoids. This runs counter to archetypical Mesozoic basaltic underplating as commonly believed. We further show that the Archean mafic lower crust persists on a cratonic scale in the North China craton presently. Re-examination of mafic granulite xenoliths from many other cratons that were considered to be products of Proterozoic underplating shows that most of them have similar genetic mechanism to the present case, suggesting that they may form in the Archean. This attests to preservation of the Archean mafic lower crust globally, contrary to the widely held concept that much of the Archean mafic lower crust has delaminated. We predict preservation of such mafic lower crust beneath all Archean cratons. It suggests that the quantity of Archean rocks in the lower crust may be much greater than that exposed.
Photoactivated reversible addition fragmentation chain transfer (RAFT)‐based dynamic covalent chemistry is incorporated into liquid crystalline networks (LCNs) to facilitate spatiotemporal control of ...alignment, domain structure, and birefringence. The RAFT‐based bond exchange process, which leads to stress relaxation, is used in a variety of conditions, to enable the LCN to achieve a near‐equilibrium structure and orientation upon irradiation. Once formed, and in the absence of subsequent triggering of the RAFT process, the (dis)order in the LCN and its associated birefringence are evidenced at all temperatures. Using this approach, the birefringence, including the formation of spatially patterned birefringent elements and surface‐active topographical features, is selectively tuned by adjusting the light dose, temperature, and cross‐linking density.
Reversible addition fragmentation chain transfer is implemented in liquid crystalline networks. The alignment of the liquid crystals is spatially and temporally controlled via stress relaxation at various temperatures. Thermally reversible optical images and surface patterns, attributed to the disruption and stabilization of orientation during rearrangement, are written into aligned networks, confined in cells and on surfaces.
MicroRNAs (miRNAs) are a class of noncoding RNAs that regulate target gene expression at the posttranscriptional level. Here, we report that secreted miRNAs can serve as signaling molecules mediating ...intercellular communication. In human blood cells and cultured THP-1 cells, miR-150 was selectively packaged into microvesicles (MVs) and actively secreted. THP-1-derived MVs can enter and deliver miR-150 into human HMEC-1 cells, and elevated exogenous miR-150 effectively reduced c-Myb expression and enhanced cell migration in HMEC-1 cells. In vivo studies confirmed that intravenous injection of THP-1 MVs significantly increased the level of miR-150 in mouse blood vessels. MVs isolated from the plasma of patients with atherosclerosis contained higher levels of miR-150, and they more effectively promoted HMEC-1 cell migration than MVs from healthy donors. These results demonstrate that cells can secrete miRNAs and deliver them into recipient cells where the exogenous miRNAs can regulate target gene expression and recipient cell function.
► MVs derived from plasma and cultured cell medium are carriers of secreted miRNAs ► Cells selectively secrete miRNAs via MVs in response to stimuli ► Secreted miRNAs serve as signaling molecules mediating intercellular communication ► Secreted monocytic miR-150 modulates targeted endothelial cell function
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