Dual-network carboxymethyl chitosan conductive hydrogels for multifunctional sensors and high-performance triboelectric nanogenerators.

With the development of technology, there is a growing demand for wearable electronics that can fulfill different application scenarios. Hydrogel-based sensors are considered ideal candidates for realizing multifunctional wearable flexible devices. However, there are great challenges in preparing hydrogel-based sensors with both superior mechanical and electrical properties. Herein, we report a composite conductive hydrogel prepared by using a dynamically crosslinked carboxymethyl chitosan network and a covalently crosslinked polymer network, and carboxylated carbon nanotubes as conductive filler. The carboxymethyl chitosan-based hydrogels had excellent mechanical properties and strength (tensile strength of 475.4 kPa, and compressive strength of 1.9 MPa) and ultra-high conductivity (0.19 S·cm-1). Based on the above characteristics, the hydrogel could accurately identify the movement signals of the human body and different writing signals, and achieve encrypted transmission of signals, broadening the application scenarios. In addition, a triboelectric nanogenerator (TENG) was fabricated based on the hydrogel, which had an outstanding output performance with open-circuit voltage of 336 V, short-circuit current of 18 µA, transferred charge of 52 nC and maximum power density of 340 mW·m-2, and could power small devices. This work is expected to provide new ideas for the development of self-powered, multi-functional wearable, and flexible polysaccharide-based devices.

Liquid-free ionic conductive elastomers with high mechanical properties and ionic conductivity for multifunctional sensors and triboelectric nanogenerators.

Liquid-free ionic conductive elastomers (ICEs) are ideal materials for constructing flexible electronic devices by avoiding the limitations of liquid components. However, developing all-solid-state ionic conductors with high mechanical strength, high ionic conductivity, excellent healing, and recyclability remains a great challenge. Herein, a series of liquid-free polyurethane-based ICEs with a double dynamic crosslinked structure are reported. As a result of interactions between multiple dynamic bonds (multi-level hydrogen bonds, disulfide bonds, and dynamic D-A bonds) and lithium-oxygen bonds, the optimal ICE exhibited a high mechanical strength (1.18 MPa), excellent ionic conductivity (0.14 mS cm-1), desirable healing capacity (healing efficiency >95%), and recyclability. A multi-functional wearable sensor based on the novel ICE enabled real-time and rapid detection of various human activities and enabled recognizing writing signals and encrypted information transmission. A triboelectric nanogenerator based on the novel ICE exhibited an excellent open-circuit voltage of 464 V, a short-circuit current of 16 µA, a transferred charge of 50 nC, and a power density of 720 mW m-2, enabling powering of small-scale electronic products. This study provides a feasible strategy for designing flexible sensor products and healing, self-powered devices, with promising prospects for application in soft ionic electronics.

Ultrastable, Superrobust, and Recyclable Supramolecular Polymer Networks.

Supramolecular polymer networks (SPNs), crosslinked by noncovalent bonds, have emerged as reorganizable and recyclable polymeric materials with unique functionality. However, poor stability is an imperative challenge faced by SPNs, because SPNs are susceptible to heat, water, and/or solvents due to the dynamic and reversible nature of noncovalent bonds. Herein, the design of a noncovalent cooperative network (NCoN) to simultaneously stabilize and reinforce SPNs is reported, resulting in an ultrastable, superrobust, and recyclable SPN. The NCoN is constructed by multiplying the H-bonding sites and tuning the conformation/geometry of the H-bonding segment to optimize the multivalence cooperativity of H-bonds. The rationally designed H-bonding segment with high conformational compliance favors the formation of tightly packed H-bond arrays comprising higher-density and stronger H-bonds. Consequently, the H-bonded crosslinks in the NCoN display a covalent crosslinking effect but retain on-demand dynamics and reversibility. The resultant ultrastable SPN not only displays remarkable resistance to heat up to 120 °C, water soaking, and a broad spectrum of solvents, but also possesses a superhigh true stress at break (1.1 GPa) and an ultrahigh toughness (406 MJ m-3 ). Despite the covalent-network-like stability, the SPN is recyclable through activating its reversibility in a high-polarity solvent heated to a threshold temperature.

BaSO4-Epoxy Resin Composite Film for Efficient Daytime Radiative Cooling.

Conventional cooling methods are based on active cooling technology by air conditioning, which consumes a large amount of energy and emits greenhouse gases. Radiative cooling is a novel promising passive cooling technology that uses external space as the cooling source and requires no additional energy consumption. Herein, we propose an approach to prepare highly dispersed BaSO4 nanoparticles (NPs) using a direct precipitation method combined with the in situ surface modification technology. The as-prepared PVP-modified BaSO4 NPs with an average size of 20 nm can be stably dispersed in ethanol for more than 6 months and then were used as building blocks to prepare spherical BaSO4 clusters with an average size of 0.9 µm using a scalable spray drying technique. The BaSO4 NPs/clusters (mass ratio 1:1) were used for preparing radiative cooling epoxy resin film, showing a high solar reflectance of 71% and a high sky window emissivity of 0.94. More importantly, this composite film displays superior radiative cooling performance, which can reduce the ambient temperature by 13.5 °C for the indoor test and 7 °C for the outdoor test. Compared with the commercial BaSO4 filled film, our BaSO4-epoxy resin composite film offers advantages not only in radiative cooling but also in mechanical properties with a 16.6% increase of tensile strength and 40.1% increase of elongation at break, demonstrating its great application potential in the field of building air conditioning.

Facile Preparation of a Low-Cost Liquid Interlayer Material with Intelligent UV-NIR-Shielding Function for Smart Windows.

High-performance interlayer materials have garnered considerable interest owing to their low manufacturing costs and applicability in smart windows. In this study, a novel smart-window interlayer material capable of selective shielding against both near-infrared (NIR) and ultraviolet (UV) radiation is developed based on the light transmittance control mechanism. An excellent thermoresponsive liquid, denoted as CDs@TRL (viz., carbon quantum dots at thermal-responsive liquid), is synthesized by compositing biomass-based fluorescent carbon quantum dots (CDs) and poly(N-isopropylacrylamide) (pNIPAM) at natural ambient temperature and in an aqueous phase. Due to the characteristics of CDs and synergistic effect of hydrogen bonds, CDs@TRL exhibits a high specific heat capacity (4.41 kJ kg-1 K-1), large thermal storage capacity (264.6 kJ kg-1), and better UV-NIR-blocking properties, compared to pure pNIPAM, as well as improves the sensitivity of thermal response. When injected into a window as a liquid interlayer, CDs@TRL can intelligently adjust the light transmittance according to ambient light intensity to achieve an intelligent response. The shielding rate of a 10 mm-thick CDs@TRL composite liquid against UV radiation (200-400 nm) was more than 95% in an overcast environment with insufficient light and close to 100% in a well-lighted environment. In addition, CDs@TRL is a cost-effective material that can be prepared from a wide range of raw material sources using a simple preparation process and exhibits excellent mobility and recyclability. Because of these features, it is considered to be a promising candidate for developing energy-saving and climate-adapted smart windows.

One-step hydrothermal method synthesized pH-dependent carbon dots for multistage anti-counterfeiting.

Work to combat counterfeiting has always been crucial to defending the interests of the public. The usual anti-counterfeiting marks are now fundamental and easy to imitate. Therefore, it is more beneficial to anti-counterfeiting work to develop an anti-counterfeiting mark with more variations to make forgery more difficult. Due to its exceptional stability and fluorescence variability, carbon dots (CDs), a newly developed fluorescent material, offer a wide range of potential applications in anti-counterfeiting. However, there currently needs to be more CD applications in multi-level anti-counterfeiting, and additional issues include high cost and environmental contamination. Therefore, considering the problems of green environmental protection and cost, CDs with excellent green (530 nm) and blue (475 nm, 486 nm) luminescence properties were prepared by a one-step reaction of m-phenylenediamine and glucose. The average fluorescence lifespan is longer than 5 ns, and the optimal quantum yield can reach 37%. Due to the large number of protonated amino groups and surface carboxyl functional groups, the prepared carbon dots exhibit green and blue fluorescence emission modes under acidic and alkaline conditions, respectively. Based on this situation, we produced CD ink and successfully used it for multi-level anti-counterfeiting.

The association of preoperative high-sensitivity cardiac troponin i and long-term outcomes in colorectal cancer patients received tumor resection surgery.

BACKGROUND: This study aimed to evaluate the association between preoperative hs-cTnI and long-term mortality and major adverse cardiovascular events (MACE) in colorectal cancer patients. METHODS: This single-center retrospective cohort study included 1105 consecutive colorectal cancer patients who received tumor resection surgery between January 2018 and June 2020. Inclusion criteria were an age ≥ 18 years and had been tested for hs-cTnI on admission within 7 days prior to tumor resection surgery. Exclusion criteria were emergent surgery, failure to received tumor resection surgery, hospital death, there was clinical evidence of unstable coronary artery disease or pulmonary embolism occurred before operation according to medical record. The primary endpoint was all-cause death. Secondary endpoint was major adverse cardiovascular events (MACE). RESULTS: A total of 1105 patients were enrolled: 1032 with normal hs-cTnI and 73 with elevated hs-cTnI. The mean follow-up was 24.4 ± 10.8 months, 176 patients died and 39 patients met MACE. In the elevated troponin group, 50%, 32.1% and 17.9% died from cancer, cardiovascular and other causes, while those in the normal troponin group were 75.7%, 2% and 22.3%, there was statistical difference between 2 groups (P < 0.001). Patients with elevated preoperative hs-cTnI had significantly higher mortality (P < 0.001) and more MACE (P < 0.001) compared with those with normal hs-cTnI. A propensity-matching analysis were performed, resulting in 151 patients with normal hs-cTnI and 60 patients with elevated hs-cTnI. The matched population had the similar results for all-cause death (P = 0.009) and MACE (P = 0.001). The results were consistent after further excluding 147 patients who had received chemoradiotherapy prior to surgery in subgroup analysis. The results of multivariate Cox regression analysis shown that hs-cTnI was one of the best predictors for all-cause death (hazard ratio [HR] 2.278; 95% confidence interval [CI] 1.19-4.361) and MACE (HR, 3.523; 95%CI, 1.477-8.403) in total populations, similar results were found in subgroup analysis. CONCLUSIONS: Colorectal cancer patients without myocardial ischemia manifestation but with elevated hs-cTnI prior to tumor resection surgery were at increased risk for long-term all-cause death and MACE, irrespective of whether they have received chemoradiotherapy prior to surgery.

An intelligent cooling material modified with carbon dots for evaporative cooling and UV absorption.

The emergence of cooling technology has brought about huge social benefits to society, but it is also accompanied by the serious problem of energy consumption. In countries close to the equator, intense solar radiation is accompanied by unbearable high temperatures and strong ultraviolet radiation. Therefore, we prepared a simple hydrogel with good evaporative cooling, which can work continuously and has good UV absorption, to solve the indoor cooling and UV radiation problems. Polyacrylamide (PAM) in the hydrogel provides a mechanically strong backbone, and polyethylene glycol (PEG) slows water loss and provides the hydrogel with the ability to reflect infrared light. Lithium bromide (LiBr) is a highly efficient water vapor absorbent, which can provide the hydrogel with water regeneration capability. Carbon dots (CDs) can provide excellent UV absorption for hydrogels, and CDs (4.28 kJ kg-1 K-1) have a higher specific heat capacity than water (4.20 kJ kg-1 K-1), which can store more heat for a better indoor cooling effect. The composite hydrogel has a good prospect of application in the windows of residential and high-rise buildings.

Disaster propagation in interdependent networks with different link patterns.

Disaster propagation in complex, interdependent, and multilayered networks has attracted considerable research interest in recent years. In this paper, we propose a model that combines two dynamic mechanisms, i.e., the spreading of failure in layer-dependent networks, where each node in a layer depends on one in another layer. We first investigate the robustness of the Erdos-Rényi (ER)-ER, scale-free (sf)-ER, and sf-sf pattern of interdependent networks against cascading failure with different probabilities of triggering, and then use the random link, assortative link, and disassortative link patterns between the networks to analyze the scope of propagation of failure. The numerical results show that with increasing probability of triggering, the number of damaged nodes in both layers increased and the robustness of the scale-free network to random failures decreased due to the interdependence. Regardless of the topological structure, the two layers eventually tended to have similar failure characteristics due to their interdependence. In addition, the different link patterns had a significant effect on enhancing disaster propagation in interdependent networks.

C/EBPZ modulates the differentiation and proliferation of preadipocytes.

BACKGROUND/OBJECTIVES: This study investigated the functions of CCAAT/enhancer-binding protein zeta (C/EBPZ; Gene ID: 10153) in adipose tissue. SUBJECTS/METHODS: Bioinformatics analysis were used to study the expression pattern of C/EBPZ in human adipose tissue. The expression and function of C/EBPZ in adipose tissue were further studied using chicken as animal model in vivo and in vitro. RESULTS: The human C/EBPZ transcripts were greater and more stable in subcutaneous adipose tissue than in visceral adipose tissue (P < 0.01), and they were increased with age in adipose tissue (P < 0.05). In addition, the chicken C/EBPZ transcripts (C/EBPZ /ACTB) of visceral (abdominal) adipose tissue were significantly different between fat and lean broilers and decreased with age during development (P < 0.01). RNA-seq analysis showed that the C/EBPZ overexpression associated with adipose tissue development and DNA replication in chicken preadipocytes (P < 0.05). Additionally, overexpression of chicken C/EBPZ inhibited preadipocytes differentiation and promoted preadipoytes proliferation in vitro (P < 0.05). In addition, C/EBPZ overexpression suppressed the promoter activities of PPARγ, C/EBPα, FASN and LPL, and promoted the promoter activities of GATA2 and FABP4 in chicken preadipocytes (P < 0.05). CONCLUSIONS: C/EBPZ modulated the differentiation and proliferation of preadipocytes, and it might be a new negative regulator of adipogenesis.

Competing Endogenous RNA Network in Non-Keloid-Prone Individuals During Wound Healing.

ABSTRACT: To study the interaction between differentially expressed long non-coding RNAs (lncRNAs), microRNAs, and messenger RNAs during wound healing in normal individuals. The GSE113621 dataset was downloaded from gene expression matrix, specimens regarding non-keloid-prone individuals were selected, including items before and 6 weeks after injury. A Pearson correlation coefficient of > 0.95 was selected as the index to screen targeting relationships among different RNAs. Cytoscape was used to construct a network diagram. The expression of 2547 lncRNAs was changed during the wound healing process-1479 were upregulated and 1068 were downregulated. After analyzing competitive endogenous RNA network, 4 upregulated (MEG8, MEG3, MIR181A1HG, MIR4435-2HG) lncRNAs were found expressed during wound healing. MEG8/MEG3 may regulate fibroblast proliferation, differentiation, and apoptosis through hsa-miR-296-3p/miR-6763-5p. In-depth mining of gene expression matrix data indicated that lncRNAs and a competitive endogenous RNA regulatory network participate in the wound healing process, possibly providing novel intervention targets and treatment options for delayed wound healing.

Study of photogenerated exciton dissociation in transition metal dichalcogenide van der Waals heterojunction A2-MWS4: a first-principles study.

In order to explore the photocatalytic hydrogen production efficiency of the MoS2/WSe2 heterostructure (A2-MWS4) as a photocatalyst, it is highly desirable to study the photogenerated exciton dissociation related to photocatalysis. The electronic properties, optical absorption, and lattice dynamic properties of A2-MWS4 were investigated using a first-principles approach. The results show that the type II energy band alignment of A2-MWS4 facilitates the dissociation of photogenerated excitons (electrons and holes). The highly localized d-state electrons of A2-MWS4 induce the formation of internal potentials that promote the dissociation of photogenerated excitons. The hot carrier diffuses its extra energy into the lattice by scattering with phonons and forms a hot spot in the lattice while releasing phonons, which are dragged away from the hot spot by Ridley decay to promote exciton dissociation. These findings could provide insights for research studies on photochemical reactions and photovoltaic devices.

Characteristics and Safety of CO2 for the Fire Prevention Technology with Gob-Side Entry Retaining in Goaf.

The mining technology of gob-side entry retaining without a coal pillar is gradually becoming a mature and increasingly important mining technology. As it maintains the roadway near goaf, the air leakage should be greater than a U-type ventilation system in goaf, so it is prone to cause coal spontaneous combustion problems. CO2 is an inert gas, and it is usually used to prevent spontaneous combustion and extinguish coal fire. However, there is a lack of research on characteristics and safety of CO2 for the mining technology of gob-side entry retaining without the coal pillar. In this paper, the indexes of influencing factors were proposed on gas, pipelines, and mining technical parameters. Using a three-dimensional physical model of coal stope, the gas migration law of CO2, the relationship between gas injection rate and the oxidation zone area, and the safety of the CO2 inerting technology were analyzed. The results indicate that the O2 concentration is diluted between the working face and the injection port, especially in the air intake side. Furthermore, the CO2 injection rate is an important parameter to the fire prevention and extinguishing technology. When the gas injection rate ranges from 240 to 720 m3/h, the oxidation zone area varies from 7380 to 14 760 m2, and the gas injection rate grows exponentially with the area of the oxidation zone. Moreover, the redundant CO2 gas flows to the retaining roadway, and it reduces the O2 concentration, resulting in asphyxia accidents of miners. The research results are helpful to balance the relationship between inert gas injection and production safety and provide guidance for the practical application of the inert gas fire prevention technology.

Healable and Recyclable Elastomers with Record-High Mechanical Robustness, Unprecedented Crack Tolerance, and Superhigh Elastic Restorability.

Spider silk is one of the most robust natural materials, which has extremely high strength in combination with great toughness and good elasticity. Inspired by spider silk but beyond it, a healable and recyclable supramolecular elastomer, possessing superhigh true stress at break (1.21 GPa) and ultrahigh toughness (390.2 MJ m-3 ), which are, respectively, comparable to and ≈2.4 times higher than those of typical spider silk, is developed. The elastomer has the highest tensile strength (ultimate engineering stress, 75.6 MPa) ever recorded for polymeric elastomers, rendering it the strongest and toughest healable elastomer thus far. The hyper-robust elastomer exhibits superb crack tolerance with unprecedentedly high fracture energy (215.2 kJ m-2 ) that even exceeds that of metals and alloys, and superhigh elastic restorability allowing dimensional recovery from elongation over 12 times. These extraordinary mechanical performances mainly originate from the meticulously engineered hydrogen-bonding segments, consisting of multiple acylsemicarbazide and urethane moieties linked with flexible alicyclic hexatomic spacers. Such hydrogen-bonding segments, incorporated between extensible polymer chains, aggregate to form geometrically confined hydrogen-bond arrays resembling those in spider silk. The hydrogen-bond arrays act as firm but reversible crosslinks and sacrificial bonds for enormous energy dissipation, conferring exceptional mechanical robustness, healability, and recyclability on the elastomer.

Chiral Phosphine Oxide-Sc(OTf)3 Complex Catalyzed Enantioselective Bromoaminocyclization of 2-Benzofuranylmethyl N-Tosylcarbamates. Approach to a Novel Class of Optically Active Spiro Compounds.

An efficient enantioselective bromoaminocyclization of 2-benzofuranylmethyl N-tosylcarbamates catalyzed by a chiral phosphine oxide-Sc(OTf)(3) complex is described. A wide variety of optically active spiro benzofuran oxazolidinones can be obtained with high enantioselectivities.

catena-Poly[cobalt(II)-bis-(µ-3,7-dichloro-quinoline-8-carboxyl-ato-κN,O:O')].

In the crystal structure of the title compound, [Co(C(10)H(4)Cl(2)NO(2))(2)](n), the Co(II) cation lies on a twofold rotation axis. Each cation is N,O-chelated by the carboxyl-ate anions of two 3,7-dichloro-quinoline-8-carboxyl-ate ligands. The second carboxyl-ate O atom of each ligand coordinates to the Co(II) cation of an adjacent mol-ecule, linking the cations into a linear chain. Strong inter-chain π-π stacking inter-actions are observed in the crystal structure (perpendicular distance 3.42 Å, centroid-to-centroid distance 3.874 Å).