Size distributions reveal regime transition of lake systems under different dominant driving forces

Power law size distribution is found to associate with fractal, self-organized behaviors and patterns of complex systems. Such distribution also emerges from natural lakes, with potentially important links to the dynamics of lake systems. But the driving mechanism that generates and shapes this feature in lake systems remains unclear. Moreover, the power law itself was found inadequate for fully describing the size distribution of lakes, due to deviations at the two ends of size range. Based on observed and simulated lakes in 11 hydro-climatic zones of China, we established a conceptual model for lake systems, which covers the whole size range of lake size distribution and reveals the underlying driving mechanism. The full lake size distribution is composed of three components, with three phases featured by exponential, stretched-exponential and power law distribution. The three phases represent system states with successively increasing degrees of heterogeneity and orderliness, and more importantly, indicate the dominance of exogenic and endogenic forces, respectively. As the dominant driving force changes from endogenic to exogenic, a phase transition occurs with lake size distribution shifted from power law to stretched-exponential and further to exponential distribution. Apart from compressing the power law phase, exogenic force also increases its scaling exponent, driving the corresponding lake size power spectrum into the regime of blue noise. During this process, the autocorrelation function of the lake system diverges with a possibility of going to infinity, indicating the loss of system resilience

Animal Silk-Derived Amorphous Carbon Fibers for Electricity Generation and Solar Steam Evaporation

Animal silk-derived carbon materials are of interest to various applications, such as smart cloth and wearable sensors. However, it remains a challenge to massively transform silks into continuous carbon fibers. In this work, carbon fibers based on two kinds of animal silks, i.e., Bombyx mori (B. mori) silk and Antheraea pernyi (A. pernyi) silk, are prepared by using a large-scale-capable one-step heating process without any additives or activation process. These carbon fibers and yarns are electroconductive and mechanically robust. To expand the application of these carbonized silks, we further weaved them with cotton yarns to obtain composite fabrics with different textures and evaluated their performance for solar steam evaporation. Our results confirmed that the advantages of these composite fabrics in light absorption, large surface area, and hierarchical liquid transport channels allowed them to be used as a solar steam generation for desalination and sewage treatment. In addition, we reported that these conductive carbon fibers could be assembled into fluidic nanogenerators to generate electricity from the water flow. This work is expected to guide a large-scale preparation and use of animal silk-derived amorphous carbon fibers

NEAT1 repression by MED12 creates chemosensitivity in p53 wild‐type breast cancer cells

Breast cancer is often treated with chemotherapy. However, the development of chemoresistance results in treatment failure. Long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) has been shown to contribute to chemoresistance in breast cancer cells. In studying the transcriptional regulation of NEAT1 using multi-omics approaches, we showed that NEAT1 is up-regulated by 5-fluorouracil in breast cancer cells with wild-type cellular tumor antigen p53 but not in mutant-p53-expressing breast cancer cells. The regulation of NEAT1 involves mediator complex subunit 12 (MED12)-mediated repression of histone acetylation marks at the promoter region of NEAT1. Knockdown of MED12 but not coactivator-associated arginine methyltransferase 1 (CARM1) induced histone acetylation at the NEAT1 promoter, leading to elevated NEAT1 mRNAs, resulting in a chemoresistant phenotype. The MED12-dependent regulation of NEAT1 differs between wild-type and mutant p53-expressing cells. MED12 depletion led to increased expression of NEAT1 in a wild-type p53 cell line, but decreased expression in a mutant p53 cell line. Chemoresistance caused by MED12 depletion can be partially rescued by NEAT1 knockdown in p53 wild-type cells. Collectively, our study reveals a novel mechanism of chemoresistance dependent on MED12 transcriptional regulation of NEAT1 in p53 wild-type breast cancer cells

Self-rechargeable energizers for sustainability

Electrical energy generation and storage have always been complementary to each other but are often disconnected in practical electrical appliances. Recently, efforts to combine both energy generation and storage into self-powered energizers have demonstrated promising power sources for wearable and implantable electronics. In line with these efforts, achieving self-rechargeability in energy storage from ambient energy is envisioned as a tertiary energy storage (3rd-ES) phenomenon. This review examines a few of the possible 3rd-ES capable of harvesting ambient energy (photo-, thermo-, piezo-, tribo-, and bio-electrochemical energizers), focusing also on the devices' sustainability. The self-rechargeability mechanisms of these devices, which function through modifications of the energizers’ constituents, are analyzed, and designs for wearable electronics are also reviewed. The challenges for self-rechargeable energizers and avenues for further electrochemical performance enhancement are discussed. This article serves as a one-stop source of information on self-rechargeable energizers, which are anticipated to drive the revolution in 3rd-ES technologies

Quasi-anisotropic benefits in electrospun nickel–cobalt–manganese oxide nano-octahedron as anode for lithium-ion batteries

Despite having a significantly higher capacity (>1000 mA h g−1) as compared to the conventional graphite anode, the adoption of the conversion-type transition metal oxide (TMO) anodes is restricted due to their inferior cycling stability, sluggish ion transport behavior, high potential plateau vs. Li/Li+, etc. Subsequent developments through nanostructuring and chemical composition engineering have improved the electrochemical performance of TMO anodes. Herein, a quasi-anisotropic nano-octahedron quaternary metal oxide composite is designed and synthesized using pilot-scale electrospinning by manipulating the conductivity of the polymeric solution. This morphology is first reported via electrospinning, which routinely produces nanofiber morphology. The fabricated nano-octahedron exhibited slightly higher gravimetry specific capacity (∼1184 mA h g−1 at 100 mA g−1) as compared to the nanofiber counterpart (1075 mA h g−1 at 100 mA g−1), with an initial capacity loss of 37.4% and 38.7%, respectively. Owing to the isotropic volume expansion, the nano-octahedron was capable of retaining 78.9% (or 291.2 mA h g−1) capacity after 500 charge/discharge cycles at 1000 mA g−1, compared to the inferior 24.1% (or 71.1 mA h g−1) for its nanofiber counterpart. Overall, the results discussed here provide valuable information on morphology design for future high-performance TMO anodes

miR-182 Regulates Metabolic Homeostasis by Modulating Glucose Utilization in Muscle

SummaryUnderstanding the fiber-type specification and metabolic switch in skeletal muscle provides insights into energy metabolism in physiology and diseases. Here, we show that miR-182 is highly expressed in fast-twitch muscle and negatively correlates with blood glucose level. miR-182 knockout mice display muscle loss, fast-to-slow fiber-type switching, and impaired glucose metabolism. Mechanistic studies reveal that miR-182 modulates glucose utilization in muscle by targeting FoxO1 and PDK4, which control fuel selection via the pyruvate dehydrogenase complex (PDHC). Short-term high-fat diet (HFD) feeding reduces muscle miR-182 levels by tumor necrosis factor α (TNFα), which contributes to the upregulation of FoxO1/PDK4. Restoration of miR-182 expression in HFD-fed mice induces a faster muscle phenotype, decreases muscle FoxO1/PDK4 levels, and improves glucose metabolism. Together, our work establishes miR-182 as a critical regulator that confers robust and precise controls on fuel usage and glucose homeostasis. Our study suggests that a metabolic shift toward a faster and more glycolytic phenotype is beneficial for glucose control

In Situ Fabrication of Branched TiO2/C Nanofibers as Binder‐Free and Free‐Standing Anodes for High‐Performance Sodium‐Ion Batteries

Herein, 1D free-standing and binder-free hierarchically branched TiO2/C nanofibers (denoted as BT/C NFs) based on an in situ fabrication method as an anode for sodium-ion batteries are reported. The in situ fabrication endows this material with large surface area and strong structural stability, providing this material with abundant active sites and smooth channels for fast ion transportation. As a result, BT/C NFs with the character of free-standing membranes are directly used as binder-free anode for sodium-ion batteries, delivering a capacity of 284 mA h g−1 at a current density of 200 mA g−1 after 1000 cycles. Even at a high current density of 2000 mA g−1, the reversible capacity can still achieve as high as 204 mA h g−1. By means of kinetic analysis, it is demonstrated that the remarkable surface pseudocapacitive behavior is also a major factor to achieve excellent performance. The rationally designed structure coupled with the inherent pseudocapacitive behavior gives this material potential for sodium-ion batteries

Weathering resistance of novel sustainable prefabricated thermal insulation wall

External walls, serving as the primary medium for heat exchange between the building and the external environment, has its thermal loss comprising the largest proportion of building energy consumption. Therefore, enhancing the thermal insulation capacity of the wall is of great significance in reducing building energy consumption. In this paper, a novel sustainable prefabricated expanded polystyrene (EPS) thermal insulation wall panel with irregular column frame structures was developed. And weathering tests combined with finite element simulations were conducted to investigate its weathering performance and degradation patterns. The results revealed that In the weathering test, the panel surfaces did not exhibit apparent water seepage cracks, powdering, hollowing, peeling, etc. There was no occurrence of facing brick detachment or damage. The outer surface concrete of the wall panel experienced resistance during normal thermal expansion and contraction, generating compressive stress during expansion and tensile stress when contracted. In addition, the bond strength of the specimens decreased by 8.1% after the thermal-rain cycles, 5.1% after the thermal-cold cycles, and 12.1% after the freeze-thaw cycles. In the numerical simulations, the temperature stress at various positions on the concrete wall had a noticeable mutual restraining effect on the force deformation of the nearby concrete. There was a significant risk of cracking in the middle and around the opening, particularly in the lower part of the wall panel. This study serves as a basis for the degradation analyses and optimization design of the sandwich insulation wall panels for sustainability

Aqueous-Based Coaxial Electrospinning of Genetically Engineered Silk Elastin Core-Shell Nanofibers

A nanofabrication method for the production of flexible core-shell structured silk elastin nanofibers is presented, based on an all-aqueous coaxial electrospinning process. In this process, silk fibroin (SF) and silk-elastin-like protein polymer (SELP), both in aqueous solution, with high and low viscosity, respectively, were used as the inner (core) and outer (shell) layers of the nanofibers. The electrospinnable SF core solution served as a spinning aid for the nonelectrospinnable SELP shell solution. Uniform nanofibers with average diameter from 301 ± 108 nm to 408 ± 150 nm were obtained through adjusting the processing parameters. The core-shell structures of the nanofibers were confirmed by fluorescence and electron microscopy. In order to modulate the mechanical properties and provide stability in water, the as-spun SF-SELP nanofiber mats were treated with methanol vapor to induce β-sheet physical crosslinks. FTIR confirmed the conversion of the secondary structure from a random coil to β-sheets after the methanol treatment. Tensile tests of SF-SELP core-shell structured nanofibers showed good flexibility with elongation at break of 5.20% ± 0.57%, compared with SF nanofibers with an elongation at break of 1.38% ± 0.22%. The SF-SELP core-shell structured nanofibers should provide useful options to explore in the field of biomaterials due to the improved flexibility of the fibrous mats and the presence of a dynamic SELP layer on the outer surface

Directed Growth of Silk Nanofibrils on Graphene and Their Hybrid Nanocomposites

Combination of proteins with other nanomaterials offers a promising strategy to fabricate novel hybrids with original functions in biology, medicine, nanotechnology, and materials science. Under carefully selected experimental conditions, we show that graphene nanosheets are able to direct one-dimensional self-assembly of silk fibroin, forming an unprecedented type of nanohybrids. These silk/graphene hybrids combine physical properties of both constituents and form functional composites with well-ordered hierarchical structures. Due to the facile fabrication process and their tunable nanostructures, the resultant hybrids show promise in applications as diverse as tissue engineering, drug delivery, nanoelectronics, nanomedicine, biosensors, and functional composites.ISSN:2161-165