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The demand for thermally conductive but electrically insulating materials has increased greatly in advanced electronic packaging. To this end, polymer-based composites filled with boron nitride (BN) nanosheets have been intensively studied as thermal interface material (TIM). However, it remains a great challenge to achieve isotropically ultrahigh thermal conductivity in BN/polymer composites due to the inherent thermal property anisotropy of BN nanosheets and/or the insufficient construction of the 3D thermal conductive network. Herein, we present a high-performance BN/polymer composite with a biaxially oriented thermal conductive network by a dendritic ice template. The composite exhibits both ultrahigh in-plane (∼39.0 W m

Vacuum preloading combined with prefabricated vertical drains (PVDs) system has been widely used to improve the soft clay with high water content. Clogging is usually formed around the PVDs during the vacuum preloading, impeding the propagation of the vacuum pressure and slowing down the consolidation process. To understand the forming mechanism of the clogging, particle image velocimetry (PIV) technique and particle tracking velocimetry (PTV) technique were adopted in the model test of vacuum preloading test. Through this study, three stages can be identified from the results of water volume discharge rate and maximum displacements versus time. In the first stage, the soil around the PVD is horizontally consolidated, which leads to the rapid formation of clogging. In the second stage, the formation of clogging slows down due to the loss of vacuum pressure, which further reduces the drainage. In the third stage, the clogging tends to be stable, and the drainage consolidation rate is significantly reduced. PTV results show that there is a difference in the displacement of large and small particles during improvement. Two methods were proposed to estimate the thickness of clogging zone, reflecting a growing layer of clogging zone compressed around the PVD. This study provides new insights to investigate the formation mechanism of clogging during vacuum preloading test.

Rubber nanocomposites experiencing dynamic shears at large strain amplitudes (γ) exhibit the nonlinear Payne effect featured by decays of storage and loss moduli (G′ and G″) or by G′ decay accompanied with G″ overshoot near a critical strain amplitude. The occurrence of the Payne effect has been assigned to damages of “filler network” and rubber-filler interfacial interactions for a long time and to Rouse dynamics of rubber chains recently. To solve the dispute, influences of extraction, crosslinking, and paraffin swelling on the Payne effect of carbon black filled natural rubber nanocomposites are investigated systematically. Master curves of G′ as a function of γ could be always created, and overshoot of G″ in the filled vulcanizates weakens with increasing filler content and intensifies by dilution via paraffin swelling, suggesting that the Payne effect is not mainly rooted in the “filler network” and rubber-filler interfacial interactions. The filler reduces the onset strain amplitude of the Payne effect by amplifying microscopic strain amplitude of the rubber phase, irrespective of whether the matrix is crosslinked or not and whether the crosslinked matrix is swollen or not. Partial removal of bound rubber by compounding the paraffin swollen compounds could lower modulus and eliminate G″ overshoot of the deswollen vulcanizates without influence on the mechanism of G′ decay accompanying Payne effect. The overshoot is found to be closely related to the overall viscous characteristic of the vulcanizates in the linear viscoelastic regime. Provided herein are new insights for recognizing the important roles of the viscoelastic rubber phase on the Payne effect of the nanocomposites.

High-strength nonmetallic materials with low infrared (IR) emission are rare in nature, yet highly anticipated especially in military and aerospace fields for thermal camouflage, IR stealth, energy-saving heating. Here, we reported a high-strength (422 MPa) nonmetallic film with very low IR emissivity (12%), realized by constructing alternating multilayered structures consisting of successive MXene functionalized outer layers and continuous GO reinforced inner layers. This nonmetallic film is capable of competing with typical stainless steel (415 MPa, 15.5%), and exhibits remarkable thermal camouflage performance (Δ

This study aims to investigate the effects of CLAUDIN-6 (CLDN6) on cell apoptosis and proliferation of bovine cumulus cells (CCs). Immunofluorescence staining was used to localize CLDN6 protein in CCs. Three pairs of siRNA targeting CLDN6 and one pair of siRNA universal negative sequence as control were transfected into bovine CCs. Then, the effective siRNA was screened by real-time quantitative PCR (RT-qPCR) and Western blotting. The mRNA expression levels of apoptosis related genes (CASPASE-3, BAX and BCL-2) and proliferation related genes (PCNA, CDC42 and CCND2) were evaluated by RT-qPCR in CCs with CLDN6 knockdown. Cell proliferation, apoptosis and cell cycle were detected by flow cytometry with CCK-8 staining, Annexin V-FITC staining and propidium iodide staining, respectively. Results showed that the CLDN6 gene was expressed in bovine CCs and the protein was localized in cell membranes and cytoplasms. After CLDN6 was knocked down in CCs, the cell apoptosis rate significantly decreased and the pro-apoptotic genes BAX and CASPASE-3 were down-regulated significantly, whereas the anti-apoptotic gene BCL-2 was markedly up-regulated (p < 0.05). Additionally, CLDN6 knockdown significantly enhanced cell proliferation of CCs at 72 h after siRNA transfection. The mRNA levels of proliferation-related genes PCNA, CCND2 and CDC42 increased obviously in CCs with CLDN6 knockdown (p < 0.05). After CLDN6 was down-regulated, the percentage of CCs at S phase was significantly increased (p < 0.05). However, there was no remarkable difference in the percentages of cells at the G0/G1 phase and G2/M phase between CCs with or without CLDN6 knockdown (p > 0.05). Therefore, the expression of CLDN6 and its effects on cell proliferation, apoptosis and cell cycle of bovine CCs were first studied. CLDN6 low expression inhibited cell apoptosis, induced cell proliferation and cell cycle arrest of bovine CCs.

Heating the human body to maintain a relatively constant temperature is pivotal for various human functions. However, most of the current heating strategies are energy-consuming and energy-wasting and cannot cope with the complex and changing environment. Developing materials and systems that can heat the human body precisely via an efficient energy-saving approach no matter indoors/outdoors, day/night, and sunny/cloudy is highly anticipated for mitigating the growing energy crisis and global warming but is still a great challenge. Here, we demonstrate the low mid-infrared radiative (mid-IR) emissivity characteristic of Ti3C2Tx MXene and then apply it for energy-free passive radiative heating (PRH) on the human body. Our strategy is realized by simply decorating the cheap nanoporous polyethylene (nanoPE) textile with MXene. Impressively, the as-obtained 12 μm thick MXene/nanoPE textile shows a low mid-IR emissivity of 0.176 at 7-14 μm and outstanding indoor PRH performance on the human body, which enhances by 4.9 °C compared with that of traditional 576 μm thick cotton textile. Meanwhile, the MXene/nanoPE textile exhibits excellent active outdoor solar heating and indoor/outdoor Joule heating capability. The three heating modes integrated in this wearable MXene/nanoPE heating system can be switched easily or combined arbitrarily, making this thin heating system able to heat the human body precisely in various scenarios like indoors/outdoors, day/night, and sunny/cloudy, providing multiple promising and energy-saving solutions for future all-day personal precision thermal management.

High oxygen levels and root exudates together provide a resource-enriched habitat for rhizosphere microbes that, in turn, foster plant growth and perform key ecological functions. Plant genotype is a main factor shaping rhizosphere bacterial communities; however, the influence of plant genotype on the rhizosphere bacterial community of aquatic macrophytes remains unknown. Here we collected samples of the rhizosphere and bulk sediments of two genotypes of the macrophyte Phragmites australis from the littoral areas of freshwater lakes in China. High-throughput sequencing of the 16S rRNA gene was used to characterize the rhizosphere bacterial community. We found that the rhizosphere recruited a distinct bacterial community relative to that of the bulk sediment. The rhizosphere microbial community was characterized by distinct community composition and core OTUs comprising a few dominant taxa involved in the regulation of plant fitness and nutrient cycling. These taxa included Arthrobacter, Pseudomonas, Trichococcus, and Ramlibacter. Network analysis showed distinct co-occurrence patterns and a genotype-specific preference for hub taxa within the rhizosphere bacterial communities of each genotype. Functional analysis revealed difference between the relative abundance of functional groups participating in C, N, and S cycling. Our results improve our understanding of the composition of the rhizosphere bacterial community of aquatic macrophytes and highlight the importance of a comprehensive consideration of plant genotype in plant bioremediation in aquatic ecosystems.

： Backgoun：Asthma and dry eye disease are common clinical diseases. Studies have shown that asthma is related to dry eye, but there is no high-quality evidence-based medical evidence. Method：This protocol and final study will be conducted in accordance with the Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement. We will search PubMed, EMBASE, ISI Web of Science, China National Knowledge Infrastructure for all relevant literature published from their inception up to August 1, 2020. Literature search, data extraction and quality assessment will be carried out independently by two researchers, and a third researcher will resolve differences when necessary. The association between dry eye disease and asthma will indicate as odds ratio (OR) with 95% confidence interval (95% CI) and statistically analyzed using RevMan 5.3 software. If the studies included have high heterogeneity, we will conduct sensitivity analysis and subgroup analysis. Results：The protocol is intended to guide a meta-analysis aimed at identifying and quantifying the association between asthma and dry eye disease.

Residual stress is very important for the study of cardiovascular-relevant issues, such as assessing the vulnerability of atherosclerosis and aneurysm. In this paper, the circumferential residual stress of porcine aorta was characterized by combining ex vivo experiments with numerical studies. In the experiments, porcine aortic rings were prepared and cut open, and the cross sections of the opened aortic rings were extracted to construct finite element models. The 5-parameter Mooney–Rivlin model was chosen to describe the tensile mechanical behavior of the aorta. In numerical studies, based on the finite element models and hyperelastic material model, a pulling-back displacement was applied to reclose the models of the opened aortic rings, and the equivalent circumferential residual stress to the pre-opened aorta was analyzed. The results showed that the circumferential residual stress of the aorta generally decreased from the proximal to the distal ends, and the residual stresses of the aortic rings close to the distal end did not show a great difference. This work provides an improved understanding of the residual stress distribution in aorta and may be used as a more realistic initial condition for future stress analysis of the arterial tissue.

Hydrogels are peculiarly attractive electrolyte materials for constructing flexible and secure all-solid-state supercapacitors due to their mechanical flexibility, ionic conductivity and noninflammability. However, upon severe mechanical stresses, hydrogel electrolyte-based supercapacitors will undergo irreversible structural damage, which results in dramatically fluctuant energy output. Additionally, invalid mechanical flexibility and serious capacitance degradation at subzero temperature are also urgent issues to be addressed. Herein, a mechanically reliable, exceptional-performance and anti-freezing all-solid-state supercapacitor is constructed from a highly ionic conductive double-network (DN) hydrogel electrolyte, intrinsically powerful Ti3C2Tx MXene film electrode and carbon nanotube film current collector. The DN hydrogel possesses impressive ionic conductivities of 4.8 and 3.6 S m−1 at room temperature and −20 °C, respectively, together with an effective energy-dissipation mechanism and freezing tolerance (

Filled vulcanizates exhibit the nonlinear Payne effect under dynamic deformations at high strain amplitudes, while the underlining mechanisms are still in dispute. Herein, polydimethylsiloxane (PDMS) networks are prepared via end-linking of α,ω-vinyl-terminated PDMS chains by the thiol-ene reaction, and the influences of silica on the dynamic rheological responses are investigated. The presence of silica tends to improve the crosslinking density alongside reinforcing the network, while silica itself does not contribute to the loss factor markedly. Furthermore, silica could promote the onset strain amplitude of the Payne effect and manifest the very weak overshoot of loss modulus near the onset amplitude. By creating master curves of the Payne effect of the filled vulcanizates referenced to the end-linking networks, it is evidenced that this effect and the accompanied weak overshoot are mainly rooted in the nonlinear Rouse dynamics of the network strands.

The burgeoning development of wearable electronic devices has resulted in urgent demands for electromagnetic interference (EMI) shielding films that feature excellent fireproof and heat dissipation capability. Herein, multifunctional fireproof EMI shielding films with excellent anisotropic thermal conductivity are constructed based on MXene and montmorillonite (MMT) via a simple vacuum-assisted filtration technique. The presence of MMT can protect the MXene from oxidation and endow the composite films with exceptional fire-resistant ability. The impressive thermal conductivity performance, high in-plane thermal conductivity (28.8 W m

Conductive hydrogels have attracted intensive attention for versatile functions in flexible electronics because of their unique combination of mechanical flexibility and conductivity. However, hydrogels containing plenty of water inevitably freeze at subzero temperature, leading to invalid electronics with failed mechanical advantages and negligible conductivity. Moreover, the inferior elasticity and fatigue resistance of hydrogels result in unstable sensing performance and poor reusability of hydrogel-based electronics. Herein, a freezing-tolerant, high-sensitive, durable strain and pressure sensor was constructed from an ionic conductive chitosan-poly(acrylamide-co-acrylic acid) double-network [CS-P(AM-co-AA) DN] hydrogel with dual-dynamic cross-links (chitosan physical network and ionic coordination [CO2LFeIII]), which was feasibly fabricated by soaking the CS-P(AM-co-AA) composite hydrogel in FeCl3 solution. The ions immobilized in dynamic cross-links exerted crucial effects on improving mechanics [prominent tensile performance, supercompressibility, extraordinary elasticity, fast self-recovery capacity, and remarkable fatigue resistance (1000 cycles)]; meanwhile, the free ions in the hydrogel rendered the hydrogel excellent conductivity and strong freezing tolerance concurrently. The sensor assembled from the DN hydrogel exhibited cycling stability and good durability in detecting pressure, various deformations (elongation, compression, and bend), and human motions even at a low temperature (-20 °C). Notably, the sensitivity on detecting strain and pressure at both room and subzero temperature was superior than most of the reported organohydrogel and hydrogel sensors. Thus, we believe that this work will provide a platform for construction and application of high-sensitive strain and pressure hydrogel sensors with cycling stability and good durability in a wide temperature range.

Oxidative stress alters cellular microenvironment, facilitating cell apoptosis and inflammatory response, and oxidation of lens constituents may ultimately result in cataracts. Astragaloside IV (AS-IV) exhibits a variety of pharmacological activities, such as antioxidative and anti-inflammatory activity via regulating various signaling pathways. However, the effect of AS-IV on lens epithelial cells and its potential therapeutic role in cataracts remained to be investigated. In this study, AS-IV prevented H

Na Gao,1,&ast; Linghui Xiao,1,&ast; Zheng Tao,2 Yanlin Zheng,1 Wanjie Wang,1 Hui Huang1 1Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, People’s Republic of China; 2Eye College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Hui Huang, Hospital of Chengdu University of Traditional Chinese Medicine, No. 39 Shi-er-qiao Road, Jinniu District, Chengdu, 610072, Sichuan Province, People’s Republic of China, Tel +86-18782917219, Fax +86-28-87732407, Email huanghui0021@163.comPurpose: To establish a high-glucose (HG) stressed cell model and study the expression of main components of the Dll4/Notch-VEGF signaling pathway under high-glucose stimulation.Methods: A model of HG-conditioned cells (human umbilical vein endothelial cells, HUVECs) was first established, and then the expression of Dll4, Notch1, Notch4 and VEGF in HG-stressed cells with or without Notch pathway blockage was analyzed by RT-PCR and Western blot. To observe cell migration, we also evaluated the Transwell assay.Results: HUVECs stimulated with 30mmol/L HG was selected as a cell model. RT-PCR and Western blot results showed that HG stimulation induced the expression of Dll4, Notch1 and VEGF and downregulated Notch4. The expressions were reversed after Notch pathway blockage; meanwhile, the blockage of Notch pathway inhibited cell migration under HG condition.Conclusion: The function of Notch4 in responses to HG stimulation deserves further researching. Combination therapy by blocking Dll4/Notch and VEGF pathways may provide us with a new way for anti-neovascularization.Keywords: Dll4, Notch1, Notch4, VEGF, endothelial cells

ObjectiveThis study aimed to systematically review the relationship between dry eye disease (DED) and asthma based on published population-based studies.Data sourcesPubMed, EMBASE and ISI Web of Science from their inception were searched up to October 2019.Study selectionObservational studies addressing the association between asthma and DED will be eligible.Data extraction and synthesisTwo reviewers independently conducted the data extraction and quality assessment. We used a random-effects model for all analyses. Subgroup analysis according to ethnicity was performed to test the influence of ethnicity on the association.Main outcomes and measuresSix independent studies (a total of 45 215 patients with asthma and 232 864 control subjects) were included in this review and had an average of seven stars by the Newcastle-Ottawa Scale. Our current findings suggest that the prevalence of DED was higher in the asthma group than in the control group (Z=7.42, p

Multifunctional, high-performance wearable heaters are highly desired for future human health-related applications but are generally hindered by the absence of flexibility, air-permeability, and clothes-knittability. Here, polymeric textile-based wearable heaters are constructed by decorating an MXene on the fiber surface via a simple solution dip coating technique. Alkali pretreatment of textiles enables strong interaction between the MXene and textiles through the synergistic effect of hydrogen bonds and physical rivet action. These MXene-decorated textiles (M-textiles) not only maintain the innate flexibility, comfort, light-weight and permeability characteristics of the textile substrates, but also exhibit exceptional heating performance including dual-driven energy conversion (electrothermal and photothermal), wide temperature range (40–174 °C in electrothermal and 40–204 °C in photothermal conversion), safe operating conditions (1–3.5 V for electrothermal, and NIR/FIR or abundant sunlight for photothermal conversion), and fast thermal response (reaching over 100 °C within 25 s at 2.5 V or within seconds in photothermal conversion). Impressively, the M-textiles integrate superb resistance to fire and bacteria, and a high electromagnetic interference (EMI) shielding efficiency of 42.1 dB in the X-band. These multifunctional M-textile wearable heaters are highly promising for applications in warmth-keeping, thermotherapy, deicing, heating water, EMI shielding, and antibacterial and fire protection, and are ideal candidates for future health management and protection.

Conductive hydrogels are capturing intensive attention for versatile applications in flexible wearable devices on account of their unique combination of softness, stretchability, conductivity and biocompatibility. However, most of the hydrogel sensors can only serve as single-type sensors to detect strain or pressure, accompanied by a limited detection range. Moreover, the poor anti-freezing performance is also a serious problem to be addressed for their practical applications. Herein, a multi-model, large range and anti-freezing hydrogel sensor was constructed from a high-mechanical and ionic conductive multi-crosslinked poly(vinyl alcohol) (M-PVA) hydrogel, which was prepared via incorporating chain entanglement interaction and complexation between Fe3+ ions and hydroxyl groups into the microcrystalline network through immersion treatment in Fe2(SO4)3 solution. The three reversible and reconstructable crosslinks within the M-PVA hydrogel worked in tandem to achieve ultra-stretchability (1120%), supercompressibility (98%), high toughness, fast self-recoverability and excellent fatigue resistance. Meanwhile, the introduction of Fe3+ and SO42- ions endowed the M-PVA hydrogel with good ionic conductivity and remarkable anti-freezing properties (-50 °C), which benefited the M-PVA hydrogel to act as a freezing-tolerant dressing. The assembled multi-model hydrogel sensor can sensitively and stably detect large range elongation (∼900%), compression (∼70%), bend and pressure (up to 4.60 MPa) concurrently, as well as various human activities including speaking, finger bending and treading behavior. Notably, the hydrogel sensor was capable of maintaining excellent mechanical flexibility and sensitive sensing capacity at low temperature. The M-PVA hydrogel is a promising flexible sensing material for versatile applications in ionic skin, motion recognition and intelligent wearable devices.

Since the first discovery of graphene in 2004, the scientific and industrial community is still finding fields to bring the excellent mechanical performance of graphene into full play. Herein, this review summarizes the recent advances in graphene and graphene derivatives toughened polymer nanocomposites, which gives full play to the unique two-dimensional nanostructure, extra specific surface area and ultrahigh mechanical properties of graphene and graphene derivatives. Using graphene and graphene derivatives as toughening modifier of polymers can not only enhance the toughness of the polymer matrix but also endow the polymer nanocomposites with enhanced strength. The preparation, performance and mechanism of graphene and graphene derivatives toughened polymer nanocomposites are highlighted in this review. The factors influencing the efficiency of graphene and graphene derivatives toughening polymers are discussed in detail. Current challenge and future direction in graphene and graphene derivatives toughened polymer nanocomposites are proposed for promoting the application of graphene in toughening polymers. This review provides a guidance for fabricating high-performance polymer/graphene nanocomposites.

Here we demonstrate a general approach to crafting a myriad of soluble octa-functionalized POSS derivatives by manipulating the sequential click reactions. After flexible modification with bio-functional groups, these uniform POSSs possess good biocompatibility, remarkable anticancer therapeutic effect and outstanding antibacterial activity in aqueous solutions. Notably, this ‘one-pot’ approach provides a simple strategy to produce customized POSS macromolecules, which may afford a novel platform for clear elucidation of more complex mechanisms and precise fabrication of high-performance biomaterials in various applications.

Toughness is an important parameter to evaluate the properties and determine the applicants of polymer/CNT nanocomposites. This study applies a rheological method to perform fast determination of the optimal mechanical properties and prediction of the conductive percolation regions of a polymer/CNT nanocomposite. The tunable mechanical and electrical properties of nylon1212/multi-walled carbon nanotube (MWCNT) nanocomposites with and without poly (ethylene-octene)-g-maleic anhydride (POE-g-MAH) are evaluated. Results indicate that three types of nanocomposites exhibit remarkable gel plateau in the dynamic rheological curves and their gel points change slightly. The introduction of POE-g-MAH can improve the notched Izod impact strength (NIIS) of nylon1212/MWCNT nanocomposites greatly. NIIS of all three nanocomposites first increase and then decrease with the MWCNT loading increasing. The gel points for three nanocomposites are related to the super-toughness points and located in the conductive percolation regions, indicating that the dynamic rheology can effectively determine the super-toughness points and predict the conductive percolation regions of nylon1212/MWCNT nanocomposites. Furthermore, the morphologies for three nanocomposites at the gel points unveil the new synergistic toughening mechanism. This study brings new insights for controlling the structures, properties and compound designs of polymer/CNT nanocomposites.

Engineered rubber vulcanizates may contain a low content of short fibers and a high content of nanoparticles while the effects of the different fillers on the softening behavior are not yet explored. Herein, influences of carbon black (CB) and short aramid fiber (AF) on the Payne and Mullins effects of natural rubber composites are investigated for the first time by creating master curves of dynamic modulus or dissipation energy with respect to the straining responses of the matrix. It is revealed that the composite vulcanizates demonstrate the Payne effect characterized by decay of storage modulus, weak overshoot of loss modulus, and very weak high-order harmonics; this effect is mainly dominated by the rubber matrix experiencing microscopic strain amplitude enlarged by the filler. The composite vulcanizates exhibit the Mullins effect that becomes increasingly marked with increasing filler loading and is partially recovered by thermal annealing at relatively high temperatures. The energy dissipation during cyclic tensions is rooted in the viscoelastic deformation of the matrix and the filler-rubber interfacial debonding. The former is marked at room temperature where the rubber phase undergoes a crystallization-melting process during loading-unloading. The latter being marked in the presence of a small content of AF causes yieldinglike deformation for the virgin composites at low tensile strains, and its contribution to the softening is not recoverable during thermal annealing. The results show that the viscoelastic matrix is of importance in controlling the softening of the composite vulcanizates, which will be of guiding significance to conduct research studies on high-performance rubber composites products.

Unstable hydrogel-substrate interfaces and defunctionalization at low temperature severely restrict versatile applications of hydrogel-based systems. Herein, various chitosan-polyacrylamide double-network (CS-PAM DN) ionic hydrogels were chemically linked with diverse substrates to construct robust and anti-freezing hydrogel-substrate combination, wherein the destructible CS physical network rendered effective energy dissipation mechanism to significantly enhanced the cohesion of hydrogels and the covalent linkage between PAM network with substrate surface strongly improved the interfacial adhesion. The synergistic effects enabled the CS-PAM DN hydrogels to be tightly bonded on diverse metals and inorganics. Impressively, the hydrogel-substrate combinations were freezing tolerant to well-maintain high interfacial toughness at low temperature. Notably, due to the high toughness and conductivity of hydrogel-metal interface, the hydrogel-metal combination can be utilized as a multi-model flexible sensor to detect strain and pressure within broad temperature range. This work may provide a platform for construction and emerging application of robust, anti-freezing and stable-performance hydrogel-based systems.

Heating the human body to maintain a relatively constant temperature is pivotal for various human functions. However, most of the current heating strategies are energy-consuming and energy-wasting and cannot cope with the complex and changing environment. Developing materials and systems that can heat the human body precisely via an efficient energy-saving approach no matter indoors/outdoors, day/night, and sunny/cloudy is highly anticipated for mitigating the growing energy crisis and global warming but is still a great challenge. Here, we demonstrate the low mid-infrared radiative (mid-IR) emissivity characteristic of Tisub3/subCsub2/subTsubix/i/subMXene and then apply it for energy-free passive radiative heating (PRH) on the human body. Our strategy is realized by simply decorating the cheap nanoporous polyethylene (nanoPE) textile with MXene. Impressively, the as-obtained 12 μm thick MXene/nanoPE textile shows a low mid-IR emissivity of 0.176 at 7-14 μm and outstanding indoor PRH performance on the human body, which enhances by 4.9 °C compared with that of traditional 576 μm thick cotton textile. Meanwhile, the MXene/nanoPE textile exhibits excellent active outdoor solar heating and indoor/outdoor Joule heating capability. The three heating modes integrated in this wearable MXene/nanoPE heating system can be switched easily or combined arbitrarily, making this thin heating system able to heat the human body precisely in various scenarios like indoors/outdoors, day/night, and sunny/cloudy, providing multiple promising and energy-saving solutions for future all-day personal precision thermal management.

The interaction between groundwater (GW) and surface water (SW) not only sustains runoff in dry seasons but also plays an important role in river floods. Lateral inflow is the recharge of groundwater to surface water during a river flood; this recharge is part of the GW-SW exchange. Hydrological engineers proposed the idea of modelling flood routing using the Muskingum-Cunge method, in which the GW-SW exchange is not fully considered. This study proposes an improved nonlinear Muskingum-Cunge flood routing model that considers lateral inflow; the new method is denoted as NMCL1 and NMCL2 and can simulate flood routing and calculate the GW-SW exchange. In addition, both the linear and nonlinear lateral inflows (with the channel inflows) are discussed, and the stable lateral inflows that occur due to the GW-SW exchange are considered for the first time. A sensitivity analysis shows that different parameters have different effects on the simulation results. Three different flood cases documented in the literature are selected to compare the four classical and two updated Muskingum-Cunge methods. Two different floods of the River Wye are selected to verify the accuracy of the calibrated model. The simulation results of the improved Muskingum-Cunge method are compared with the temperature inversion results measured from the Zhongtian River, China, to indicate the feasibility and reliability of the improved method. A comparison shows that, for several cases, the proposed method is capable of obtaining optimal simulation results. The proposed method inherits the ability of the Maskingum-Cunge method to simulate flood routing. Moreover, it can quantify the GW-SW exchange, and the reliability of the estimations is owed to the nonlinearity and sign flexibility of the calculated exchange process.

Equipped with complex terrain structure, physical models provide an alternative way in understanding and modeling how critical zone shapes hydrologic processes in headwaters for research and education in hydrology. However, this type of physical models is limited by frustrating rain-erosion or gully-erosion. Herein, in order to replace the real-world backfilling soil, we drew on the experience of normal concrete workmanship and adjusted the raw material’s proportion for three times. And it is found that saturated hydraulic conductivity (SHC) and field moisture capacity (FMC) are both well correlated with bulk density (BD) for the developed materials in three cases. Thereby, based on the strongest correlation (R2=0.75) between SHC and BD, two-layer alternative soil has been designed through altering BD in the physical model with complex terrain. The SHC values of alternative soil are close to that of the natural soil while the FMC values are far lower. Additionally, the non-uniform scaling of bedrock terrain was applied for the convenience of teaching and construction by zooming out a steep 0.31-ha zero-order basin 130 times horizontally and 30 times vertically. And multiple observation items, including free water level, temperature and humidity of soil, as well as outflow could provide potential opportunity to explore the role of single or combined critical zone’s element in modulating streamflow. We’d like to share this effective tool to facilitate the development of critical zone science and enrich experimental teaching methods.

A physical model demonstrating critical zone structure and flow processes in headwatersXuhui Shen1,2, Jintao Liu1,2*, Wanjie Wang2, Xiaole Han1,3, Jie Zhang2, Guofang Li2, Xiaopeng Li4, and Yue Shi2___________________1 State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China2 College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China3 School of Earth Sciences and Engineering, Hohai University, Nanjing 211100, China4 Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu 210008, China___________________*Corresponding author: Jintao Liu. Tel.: +86-025-83787803; Fax: +86-025-83786606.Running head: A physical model demonstrating critical zone structure in headwaterKeywords: Physical model; Hydrologic processes; Critical zone structures; Artificial soil

Developing models that can accurately simulate groundwater level is important for water resource management and aquifer protection. In particular, machine learning tools provide a new and promising approach to efficiently forecast long-term groundwater table fluctuations without the computational burden of building a detailed flow model. This study proposes a multistep modeling framework for simulating groundwater levels by combining the wavelet transform (WT) with the long short-term memory (LSTM) network; the framework is named the combined WT-multivariate LSTM (WT-MLSTM) method. First, the WT decomposes the groundwater level time series (i.e., the training stage) into a self-control term and a set of external-control terms. Second, Pearson correlation analysis reveals the correlations between the influencing factors (i.e., river stage) and the groundwater table, and the multivariate LSTM model incorporating external factors is built to simulate the external-control terms. Third, the spatiotemporal evolution of the groundwater level is modeled by reconstructing the sequence of each term of the groundwater level time series. Methodological applications in the Liangshui River Basin, Beijing, China and the Cibola National Wildlife Refuge along the lower Colorado River, United States, show that the combined WT-MLSTM model has a higher simulation accuracy than the standard LSTM, MLSTM, and WT-LSTM models. A comparison between the combined WT-MLSTM model and support vector machine (SVM) also demonstrates the advantage of the proposed model. Additional comparison between model forecasts and observed groundwater levels shows the model predictability for short-term time series. Further analysis reveals that the applicability of the combined WT-MLSTM model decreases with increasing distance between the groundwater well and adjacent river channel, or with the increasing complexity of the changing groundwater level patterns, which may be driven by additional controlling factors. This study therefore provides a new methodology/approach for the rapid and accurate simulation and prediction of groundwater level.

Poly(lactic) acid (PLA) is one of the most promising biobased materials, but its inherent flammability limits its applications. A novel flame retardant hexa-(DOPO-hydroxymethylphenoxy-dihydroxybiphenyl)-cyclotriphosphazene (HABP-DOPO) for PLA was prepared by bonding 9,10-dihydro-9-oxy-10-phosphaphenanthrene-10-oxide (DOPO) to cyclotriphosphazene. The morphologies, mechanical properties, thermal stability and burning behaviors of PLA/HABP-DOPO blends were investigated using a scanning electron microscope (SEM), a universal mechanical testing machine, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), limiting oxygen index (LOI), vertical burning (UL-94) and a cone calorimeter test (CCT). The LOI value reached 28.5% and UL-94 could pass V-0 for the PLA blend containing 25 wt% HABP-DOPO. A significant improvement in fire retardant performance was observed for PLA/HABP-DOPO blends. PLA/HABP-DOPO blends exhibited balanced mechanical properties. The flame retardant mechanism of PLA/HABP-DOPO blends was evaluated.

The effect of silane crosslinking reaction on properties and structure of polypropylene (PP)/ethylene–octene elastomer (POE) blends had been carried out. FTIR and gel content tests confirmed the grafting and crosslinking reaction mechanism of PP/POE blends. The incorporation of POE phase enhanced the crosslinking degree and thermal stability of blends. Crystallinity of silane-crosslinked PP/POE blends decreased sharply, and the melting points change a little with the POE content increasing. The rheological curves of silane-crosslinked PP/POE blends showed an obvious “gel point”, corresponding to the dynamic crosslinking network. Solvent resistance tests suggested crosslinking had a great improvement of solvent resistance. The blends with 30% POE had good comprehensive mechanical properties. Scanning electron microscopy images exhibited that crosslinking had a great influence on the morphologies of silane-crosslinked PP/POE blends. Characterization results indicated the “gel point” acquired from rheology had some corresponding relationship with mechanical properties and solvent resistance.

It is a challenge to develop advanced elastomers with a combination of high strength, stiffness and toughness by a relatively convenient and environmentally friendly approach. Herein, we reported a facile and environmentally friendly method to prepare hybrid crosslinked nitrile butadiene rubber (NBR) comprised of covalent and ionic bonds, and this hybrid crosslinked rubber possesses comprehensively improved mechanical properties, higher crosslinking density, deformation recovery and shape memory ability. The hybrid crosslinked NBR was prepared by incorporating 2-acrylamido-2-methyl propane sulfonic acid (AMPS) and zinc oxide (ZnO) into NBR via internal milling together with dicumyl peroxide (DCP), and then vulcanization, which is a very simple and environmentally friendly method without extra procedure or treatment. The hybrid crosslinked network in NBR has randomly distributed covalent and ionic bond crosslinks, the strong covalent bonds serve as permanent crosslinks, imparting the elasticity, whereas the weak ionic bonds reversibly rupture and reform, dissipating the energy. Because of the restricting effect of ionic bonds on segmental movement, the hybrid crosslinked NBR shows higher glass transition temperature, lower loss factor peak value and longer relaxation time. By tuning the ionic bond strength via temperature, a much smaller range of linear viscoelastic region is observed for hybrid crosslinked NBR with high content of AMPS and ZnO at a relatively higher temperature, which endows the sample with shape memory ability. This design principle of incorporating ionic bonds to strengthen vulcanized NBR should be applicable to other diene rubber materials.