Inspired by natural autonomous systems that demonstrate controllable shape, appearance, and actuation under external stimuli, a facile preparation of moisture responsive graphene‐based smart ...actuators by unilateral UV irradiation of graphene oxide (GO) papers is reported. UV irradiation of GO is found to be an effective protocol to trigger the reduction of GO; however, due to the limited light transmittance and thermal relaxation, thick GO paper cannot be fully reduced. Consequently, by tuning the photoreduction gradient, anisotropic GO/reduced GO (RGO) bilayer structure can be easily prepared toward actuation application. To get better control over the responsive properties, GO/RGO bilayer paper with a certain curvature and RGO patterns are successfully prepared for actuator design. As representative examples, smart humidity‐driven graphene actuators that mimic the cilia of respiratory tract and tendril climber plant are successfully developed for controllable objects transport.
A facile preparation of graphene actuators by unilateral UV irradiation of graphene oxide (GO) papers is reported. Anisotropic GO/reduced GO bilayer paper can be directly prepared by controlling the photoreduction gradient. As typical examples, smart humidity‐driven graphene actuators that mimic the cilia of respiratory tract and the tendril climber plant are developed for object transport.
Canonical quantization is often used to suggest new effects in quantum gravity, in the dynamics as well as the structure of space-time. Usually, possible phenomena are first seen in a modified ...version of the classical dynamics, for instance in an effective Friedmann equation, but there should also be implications for a modified space-time structure. Quantum space-time effects, however, are often ignored in this setting because they are not obvious: they require a careful analysis of gauge transformations and the anomaly problem. It is shown here how modified space-time structures and effective line elements can be derived unambiguously, provided an off-shell anomaly-free system of modified constraints exists. The resulting effective line elements reveal signature change as an inescapable consequence of nonclassical gauge transformations in the presence of holonomy modifications. The general framework is then specialized to black-hole models in loop quantum gravity. In contrast to previous studies, a self-consistent space-time structure is taken into account, leading to a new picture of black-hole interiors.
Riding on the rapid growth in electric vehicles and the stationary energy storage market, high‐energy‐density lithium‐ion batteries and next‐generation rechargeable batteries (i.e., advanced ...batteries) have been long‐accepted as essential building blocks for future technology reaching the specific energy density of 400 Wh kg−1 at the cell‐level. Such progress, mainly driven by the emerging electrode materials or electrolytes, necessitates the development of polymeric materials with advanced functionalities in the battery to address new challenges. Therefore, it is urgently required to understand the basic chemistry and essential research directions in polymeric materials and establish a library for the polymeric materials that enables the development of advanced batteries. Herein, based on indispensable polymeric materials in advanced high‐energy‐density lithium‐ion, lithium–sulfur, lithium‐metal, and dual‐ion battery chemistry, the key research directions of polymeric materials for achieving high‐energy‐density and safety are summarized and design strategies for further improving performance are examined. Furthermore, the challenges of polymeric materials for advanced battery technologies are discussed.
Polymeric materials indispensable to building safe, high‐energy‐density advanced batteries, in terms of electrode integrity, interface stability, and extending operational limits, are reviewed. The fundamental understanding of functional polymeric materials for advanced lithium battery chemistry and key research directions are discussed, thus suggesting design strategies for polymeric materials for advanced lithium batteries with improved electrochemical performances.
Chemical Marangoni propulsion enables dynamic and untethered motion by generating surface tension gradient through chemical release, thereby having great potential for the development of insect‐scale ...self‐propelled robots. However, as the release and diffusion of chemical “fuels” are commonly uncontrollable, the Marangoni propulsion is unstable, thereby restricting robotic applications. Herein, the laser fabrication of superhydrophobic swimming robots to develop controllable Marangoni propulsion based on a photothermal composite of graphene and polydimethylsiloxane is reported. By combining the microfluidic channels with photothermal air chambers, a light‐triggered switch that can control the release of chemical “fuels” is proposed. Furthermore, a superhydrophobic surface is fabricated on the swimming robot by laser treatment, which reduced water resistance and promoted propulsion. On‐demand actuation and swimming route planning are realized by programming the alcohol/air segments in the releasing channels, on‐demand actuation and swimming route planning have been realized. As a proof‐of‐concept, a Marangoni swimming robot equipped with a miniature digital camera is used in an actual environment. Therefore, this study is expected to advance the practical applications of the chemical Marangoni effect in swimming robots.
Microfluidics‐enabled superhydrophobic swimming robots that enable controllable Marangoni propulsion are fabricated, in which photothermal air chambers are proposed as light‐responsive switches for controllable chemical release. By programming, the alcohol/air segments, on‐demand actuation, and swimming route planning are realized. Proof‐of‐concept Marangoni swimming robot equipped with a miniature digital camera are driven in the wild environment.
The mammalian circadian clock is an endogenous biological timer comprised of transcriptional/translational feedback loops of clock genes. Bmal1 encodes an indispensable transcription factor for the ...generation of circadian rhythms. Here, we report a new circadian mutant mouse from gene-trapped embryonic stem cells harboring a C-terminus truncated Bmal1 (Bmal1GTΔC) allele. The homozygous mutant (Bmal1GTΔC/GTΔC) mice immediately lost circadian behavioral rhythms under constant darkness. The heterozygous (Bmal1+/GTΔC) mice displayed a gradual loss of rhythms, in contrast to Bmal1+/- mice where rhythms were sustained. Bmal1GTΔC/GTΔC mice also showed arrhythmic mRNA and protein expression in the SCN and liver. Lack of circadian reporter oscillation was also observed in cultured fibroblast cells, indicating that the arrhythmicity of Bmal1GTΔC/GTΔC mice resulted from impaired molecular clock machinery. Expression of clock genes exhibited distinct responses to the mutant allele in Bmal1+/GTΔC and Bmal1GTΔC/GTΔC mice. Despite normal cellular localization and heterodimerization with CLOCK, overexpressed BMAL1GTΔC was unable to activate transcription of Per1 promoter and BMAL1-dependent CLOCK degradation. These results indicate that the C-terminal region of Bmal1 has pivotal roles in the regulation of circadian rhythms and the Bmal1GTΔC mice constitute a novel model system to evaluate circadian functional mechanism of BMAL1.
High‐capacity anode materials are promising candidates for increasing the energy density of lithium (Li)‐ion batteries due to their high theoretical capacities. However, a rapid capacity fading due ...to the huge volume changes during charge‐discharge cycles limits practical applications. Herein, a layering‐charged polymeric binder is introduced that can effectively integrate high‐capacity anodes using a strong yet reversible Coulomb interaction and enriched hydrogen bonding. The charged polymeric binder builds a dynamically charge‐directed network on the active materials with high versatility and efficiently dissipates the electrode stress with its excellent mechanical properties. In addition, poly(ethylene glycol) (PEG) moieties of the charged binder offer a fast Li‐ion conduction pathway that can form an ultra‐thick silicon oxide (SiOx)‐based electrode (≈10.2 mAh cm−2) without compromising the reversible specific capacity and promote effective charge interaction as a mechanical modulator. Such an unprecedented charge‐directed binder provides insights into the rational design of a binder for high‐capacity anodes.
A layering‐charged polymeric binder forms charge‐directed network on the high‐capacity anodes which efficiently dissipates the stress of the electrode using a strong yet reversible Coulomb interaction and enriched hydrogen bonding. Poly(ethylene glycol) (PEG) moieties, as a mechanical modulator, in charged polymer facilitate the Li‐ion conduction which enable the formulation of an ultrathick silicon oxide (SiOx)‐based electrode (≈10.2 mAh cm−2).
Objectives
To investigate the effects of astragaloside IV on blood glucose, blood lipids, and liver function in diabetic rats.
Methods
Fifty diabetic rats were randomly placed into five groups (n = ...10 each): the diabetes mellitus (DM) group received intragastric saline, the metformin hydrochloride group received intragastric metformin hydrochloride, and the astragaloside-30, -60, and -120 groups received intragastric astragaloside 30 mg/kg, 60 mg/kg, and 120 mg/kg for 28 days, respectively. Ten non-diabetic rats received intragastric saline as controls.
Results
Relative to the DM group, fasting blood glucose, triglyceride, total cholesterol, serum alanine transaminase, and serum aspartate aminotransferase levels decreased in the astragaloside-60 and astragaloside-120 groups; serum alkaline phosphatase decreased solely in the astragaloside-120 group. Serum superoxide dismutase (SOD), glutathione (GSH-Px), and catalase (CAT) levels were elevated, while maleic dialdehyde (MDA) decreased in the astragaloside-120 group, relative to the DM group. Relative to the DM group, the liver index and liver cell apoptosis rate were reduced, while histopathological changes in liver tissue were ameliorated in the astragaloside groups; moreover, liver tissue SOD, GSH-Px, and CAT levels were increased, while liver tissue MDA was reduced.
Conclusions
Astragaloside IV can lower blood glucose, regulate blood lipids, and protect liver function in diabetic rats.
PDF
