Spider-silk-inspired strong and tough hydrogel fibers with anti-freezing and water retention properties.

Ideal hydrogel fibers with high toughness and environmental tolerance are indispensable for their long-term application in flexible electronics as actuating and sensing elements. However, current hydrogel fibers exhibit poor mechanical properties and environmental instability due to their intrinsically weak molecular (chain) interactions. Inspired by the multilevel adjustment of spider silk network structure by ions, bionic hydrogel fibers with elaborated ionic crosslinking and crystalline domains are constructed. Bionic hydrogel fibers show a toughness of 162.25 ± 21.99 megajoules per cubic meter, comparable to that of spider silks. The demonstrated bionic structural engineering strategy can be generalized to other polymers and inorganic salts for fabricating hydrogel fibers with broadly tunable mechanical properties. In addition, the introduction of inorganic salt/glycerol/water ternary solvent during constructing bionic structures endows hydrogel fibers with anti-freezing, water retention, and self-regeneration properties. This work provides ideas to fabricate hydrogel fibers with high mechanical properties and stability for flexible electronics.

Split activator of CRISPR/Cas12a for direct and sensitive detection of microRNA.

CRISPR/Cas12a-based nucleic acid assays have been increasingly used for molecular diagnostics. However, most current CRISPR/Cas12a-based RNA assays require the conversion of RNA into DNA by preamplification strategies, which increases the complexity of detection. Here, we found certain chimeric DNA-RNA hybrid single strands could activate the trans-cleavage activity of Cas12a, and then discovered the activating effect of split ssDNA and RNA when they are present simultaneously. As proof of concept, split nucleic acid-activated Cas12a (SNA-Cas12a) strategy was developed for direct detection of miR-155. By adding a short ssDNA to the proximal end of the crRNA spacer sequence, we realized the direct detection of RNA targets using Cas12a. With the assistance of ssDNA, we extended the limitation that CRISPR/Cas12a cannot be activated by RNA targets. In addition, by taking advantage of the programmability of crRNA, the length of its binding to DNA and RNA was optimized to achieve the optimal efficiency in activating Cas12a. The SNA-Cas12a method enabled sensitive miR-155 detection at pM level. This method was simple, rapid, and specific. Thus, we proposed a new Cas12a-based RNA detection strategy that expanded the application of CRISPR/Cas12a.

Pinpointing the Cl Coordination Effect on Mn-N3-Cl Moiety Toward Boosting Reaction Kinetics and Suppressing Shuttle Effect in Li-S Batteries.

Single atom catalysts (SACs) are highly favored in Li-S batteries due to their excellent performance in promoting the conversion of lithium polysulfides (LiPSs) and inhibiting their shuttling. However, the intricate and interrelated microstructures pose a challenge in deciphering the correlation between the chemical environment surrounding the active site and its catalytic activity. Here, a novel SAC featuring a distinctive Mn-N3-Cl moiety anchored on B, N co-doped carbon nanotubes (MnN3Cl@BNC) is synthesized. Subsequently, the selective removal of the Cl ligands while inheriting other microstructures is performed to elucidate the effect of Cl coordination on catalytic activity. The Cl coordination effectively enhances the electron cloud density of the Mn-N3-Cl moiety, reducing the band gap and increasing the adsorption capacity and redox kinetics of LiPSs. As a modified separator for Li-S batteries, MnN3Cl@BNC exhibits high capacities of 1384.1 and 743 mAh g-1 at 0.1 and 3C, with a decay rate of only 0.06% per cycle over 700 cycles at 1 C, which is much better than that of MnN3OH@BNC. This study reveals that Cl coordination positively contributes to improving the catalytic activity of the Mn-N3-Cl moiety, providing a fresh perspective for the design of high-performance SACs.

Continuous Spinning of High-Tough Hydrogel Fibers for Flexible Electronics by Using Regional Heterogeneous Polymerization.

Hydrogel fibers have attracted substantial interest for application in flexible electronics due to their ionic conductivity, high specific surface area, and ease of constructing multidimensional structures. However, universal continuous spinning methods for hydrogel fibers are yet lacking. Based on the hydrophobic mold induced regional heterogeneous polymerization, a universal self-lubricating spinning (SLS) strategy for the continuous fabrication of hydrogel fibers from monomers is developed. The universality of the SLS strategy is demonstrated by the successful spinning of 10 vinyl monomer-based hydrogel fibers. Benefiting from the universality of the SLS strategy, the SLS strategy can be combined with pre-gel design and post-treatment toughening to prepare highly entangled polyacrylamide (PAM) and ionic crosslinked poly(acrylamide-co-acrylic acid)/Fe3+ (W-PAMAA/Fe3+ ) hydrogel fibers, respectively. In particular, the W-PAMAA/Fe3+ hydrogel fiber exhibited excellent mechanical properties (tensile stress > 4 MPa, tensile strain > 400%) even after 120 days of swelling in the pH of 3-9. Furthermore, owing to the excellent multi-faceted performance and one-dimensionality of W-PAMAA/Fe3+ hydrogel fibers, flexible sensors with different dimensions and functions can be constructed bottom-up, including the one-dimensional (1D) strain sensor, two-dimensional (2D) direction sensor, three-dimensional (3D) pressure sensor, and underwater communication sensor to present the great potential of hydrogel fibers in flexible electronics.

An all-in-one enzymatic DNA network based on catalytic hairpin assembly for label-free and highly sensitive detection of APE1.

Apurinic/apyrimidinic endonuclease 1 (APE1), identified as a prospective cancer biomarker, plays a vital role in the occurrence and progression of cancer cell lines and impacts on genome stability. However, conventional approaches typically rely on the interactions between the antigen and antibody, limiting their utility for qualitative assessments of APE1 expression. Herein, an all-in-one enzymatic DNA network (EDN) assay with catalytic hairpin assembly for label-free and ultrasensitive detection of APE1 has been developed. In this work, the blocking strand can inhibit the initiator by obstructing the complementary region, preventing the hairpin from hybridizing in the absence of APE1 targets. While the presence of targets can activate the unlocking of the initiator, which can trigger the catalytic hairpin reaction, and increase the fluorescent signal. Under optimal conditions, the developed sensing method can detect the target APE1 down to 4.78 × 10-6 U mL-1 with a wide linear range from 5 × 10-6 U mL-1 to 30 U mL-1. This strategy has also been successfully applied to the analysis of complicated biological samples compared to ELISA, demonstrating its potential applications in biochemical and molecular biology research as well as clinical diagnostics. Overall, benefiting from the high amplification efficiency, this strategy has successfully and simply detected low-abundance APE1 without additional enzyme isolation steps, presenting great potential for clinical detection applications.

Why time flies? The role of immersion in short video usage behavior.

Background: Short videos are becoming increasingly popular globally, and users are devoting more time to viewing them. However, few studies have examined the characteristics of short video content and the technical features that are related to media use. The present study developed a model to explore the influence of technological affordances on short video usage and considered innovation in terms of format, setting, and content. Method: A total of 496 viewers of short videos from China were surveyed. The participants completed 31 Likert-scale items. The study used maximum likelihood estimation modeling. Results: The results revealed that perceived novelty and content value (entertainment and irritation) affected immersion positively, consequently influencing intentions for reuse and recommendation. The ease of navigating an application, narrative structure, and information value had no significant effect on immersion. Conclusion: These findings have confirmed that perceived situation affordance and the affective affordance of short videos in digital environments that are managed by intelligent algorithms. It is necessary to analyze the potential impact of different affordances specifically.

CuSe2 Nanocubes Enabling Efficient Sodium Storage.

As the most promising candidate for lithium-ion batteries (LIBs), the electrochemical performance of sodium-ion batteries (SIBs) is highly dependent on the electrode materials. Copper selenides have established themselves as potential anode materials for SIBs due to their high theoretical capacity and good conductivity. However, the poor rate performance and fast capacity fading are the major challenges to their practical application in SIBs. Herein, single-crystalline CuSe2 nanocubes (CuSe2 NCs) are successfully synthesized via a solvothermal method. As an anode of SIBs, the CuSe2 NCs render an almost 100% initial Coulombic efficiency, an outstanding long cycle life, e.g., 380 mA h g-1 after 1700 cycles at 10 A g-1, and an unprecedented rate performance of 344 mA h g-1 at 50 A g-1. Ex situ X-ray diffraction (XRD) patterns reveal the crystalline transformation of energy-storage materials, and the density functional theory (DFT) conclusion suggests that fast and stable ion diffusion kinetics enhances their electrochemical performance upon sodiation/desodiaton. The investigation into the mechanism provides a theoretical basis for subsequent practical applications.

Does Internet Use Promote Subjective Well-Being? Evidence from the Different Age Groups Based on CGSS 2017 Data.

Mobile Internet technology has developed so rapidly that the Internet has become indispensable in everyday life. There is a continuous debate about the relationship between internet use and subjective well-being. In contrast to observing whether one has Internet access, this paper focuses on three dimensions of Internet usage: frequency of use, online relationship size, and Internet proficiency. Based on the Chinese nationwide data collected in 2017, the results of the ordinary least squares regression model demonstrate that Internet use has a significant positive association with subjective well-being. In addition, this study also discovers that the effect of Internet use on the subjective well-being of individuals of different ages is heterogeneous; middle-aged individuals benefit from more frequent Internet use and larger-scale networks; the young and older adults benefit from organizing communication in groups. The results of this study can provide targeted suggestions for improving the subjective well-being of different age groups in Internet use.

Edge Coordination of Ni Single Atoms on Hard Carbon Promotes the Potassium Storage and Reversibility.

Hard carbon is the most promising anode for potassium-ion batteries (PIBs) due to its low cost and abundance, but its limited storage capacity remains a major challenge. Herein, edge coordination of metal single atoms is proved to be an effective strategy for promoting potassium storage in hard carbon for the first time, taking B, N co-doped hard carbon nanotubes anchored by edge Ni-N4 -B atomic sites (Ni@BNHC) as an example. It is revealed that edge Ni-N4 -B can provide active sites for interlayer adsorption of K+ and that Ni atoms can facilitate the reversibility of K+ storage on N and B atoms. Furthermore, an unprecedentedly reversible K+ storage capacity of 694 mAh g-1 at 0.05 A g-1 is realized by introducing commercial carbon nanotubes. This work provides a new perspective for the application of single-atom engineering and the design of high-performance carbon anodes for PIBs.

Proposed risk-scoring model for estimating the prognostic impact of 1q gain in patients with newly diagnosed multiple myeloma.

1q gain (+1q) is the most common high-risk cytogenetic abnormality (HRCA) in patients with multiple myeloma (MM). However, its prognostic value remains unclear in the era of novel agents. Here, we retrospectively analyzed the impact of +1q on the outcomes of 934 patients newly diagnosed with MM. +1q was identified in 53.1% of patients and verified as an independent variate for inferior overall survival (OS) (hazard ratio, 1.400; 95% confidence interval, 1.097-1.787; p = .007). Concurrence of other HRCAs (particularly t(14;16) and del(17p)) further exacerbated the outcomes of patients with +1q, suggesting prognostic heterogeneity. Thus, a risk-scoring algorithm based on four risk variates (t(14;16), hypercalcemia, ISS III, and high LDH) was developed to estimate the outcomes of patients with +1q. Of the patients, 376 evaluable patients with +1q were re-stratified into low (31.6%), intermediate (61.7%), and high risk (6.7%) groups, with significantly different progression-free survival and OS (p < .0001), in association with early relapse of the disease. The prognostic value of this model was validated in the CoMMpass cohort. While attaining undetectable MRD largely circumvented the adverse impact of +1q, it scarcely ameliorated the outcome of the patients with high risk, who likely represent a subset of patients with extremely poor survival. Hence, patients with +1q are a heterogeneous group of high-risk patients, therefore underlining the necessity for their re-stratification. The proposed simple risk-scoring model can estimate the outcomes of patients with +1q, which may help guide risk-adapted treatment for such patients.

An ultrasensitive biosensing platform for FEN1 activity detection based on target-induced primer extension to trigger the collateral cleavage of CRISPR/Cas12a.

Flap endonuclease 1 (FEN1), a structure-selective endonuclease essential for DNA replication and repair, has been considered as a new promising marker for early cancer diagnosis. However, reliable, sensitive and convenient biosensors for FEN1 detection are still technically challenging. Herein, a fluorometric biosensor based on target-induced primer extension to initiate the collateral cleavage of CRISPR/Cas12a has been established for ultrasensitive and specific detection of FEN1 activity. Using branched DNA to probe FEN1 activity, the cleaved 5' flap initiated DNA polymerase-mediated primer extension to produce plenty of DNA duplexes containing protospacer adjacent motif (PAM) which act as activators to initiate the collateral cleavage activity of Cas12a protein, producing an significantly amplified fluorescence response for ultrasensitive determination of FEN1 activity. The developed biosensing platform displays excellent analytical performance, with a limit of detection (LOD) down to 8.9 × 10-5 U µL-1, and a wide linear range from 1.0 × 10-4 to 5.0 × 10-1 U µL-1. Moreover, the proposed strategy was successfully used for FEN1 detection in serums and cell lysates and suggests potential clinical applications, which may provide a reliable approach for FEN1 that will allow effective diagnosis in the early stages of related cancer.

Copolymerization-Regulated Hydrogen Bonds: A New Routine for High-Strength Copolyamide 6/66 Fibers.

Hydrogen bond interactions are important for nylon fibers, which improve its mechanical properties and crystallization behavior, while hindering the movement and orientation of the molecular chain during the drawn process. In this study, hexamethylene adipamide was used as the second monomer in copolymerization with ε-caprolactam to obtain copolyamide 6/66 (CoPA), and high-tenacity fibers with a maximum value up to 8.0 cN/dtex were achieved by a multi-step drawn and thermal setting process. Results show that the hexamethylene-adipamide ratio affected the draw ratio (DR) of the as-spun fiber, on the tenacity of final high-performance fiber, and on crystalline. Both DR and tenacity showed evident increases with the hexamethylene-adipamide ratio up to 6% in CoPA and then changed smoothly. However, XRD and DSC results illustrate a decreased tendency with regard to crystallinity. The attenuated in-site total reflection Fourier transform infrared (ATR-FTIR) spectra were used to study the hydrogen bond interaction between the C=O group and N-H group and the crystal form of the fiber. Results show that the copolymerization destroyed the regularity of the main chain of CoPA and reduces the interaction of interstrand hydrogen bonds, facilitating the formation of the γ-crystalline form in as-spun fibers, fulfilling the transition from the γ to α crystalline form during the fiber-drawing step because of the release of the C=O group and N-H group from the hydrogen bond interaction at an elevated temperature close to the molten temperature of CoPA, and then reforming during the thermal-setting step which soiled the crystalline and improved the tenacity of the fiber. The copolymerization with a homologous monomer regulates the hydrogen bond interaction, fulfills the high drawn ratio and high tenacity fiber, and provides a new route for high-performance fiber preparation using traditional fiber formation of polymers.

2D Bismuth@N-Doped Carbon Sheets for Ultrahigh Rate and Stable Potassium Storage.

Metallic Bi, as an alloying-type anode material, has demonstrated tremendous potential for practical application of potassium-ion batteries. However, the giant volume expansion, severe structure pulverization, and sluggish dynamics of Bi-based materials result in unsatisfied rate performance and unstable cycling stability. Here, 2D bismuth@N-doped carbon sheets with BiOC bond and internal void space (2D Bi@NOC) are successfully fabricated via a self-template strategy to address these issues, which own ultrafast electrochemical kinetics and impressive long-term cycling stability for delivering an admirable capacity of 341.7 mAh g-1 after 1000 cycles at 10 A g-1 and impressive rate capability of 220.6 mAh g-1 at 50 A g-1 . Particularly, the in situ transmission electron microscopy observations visualize the real-time alloying/dealloying process and reveal that plastic carbon shell and void space can availably relieve dramatic volume stress and powerfully maintain structural integrity. Density functional theory calculation and ultraviolet photoelectron spectroscopy test certify that the robust BiOC bond is thermodynamically and kinetically beneficial for adsorption/diffusion of K+ . This work will light on designing advanced high-performance energy materials and provide important evidence for understanding the energy storage mechanism of alloy-based materials.

Integrating CRISPR-Cas12a with a crRNA-Mediated Catalytic Network for the Development of a Modular and Sensitive Aptasensor.

Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas12a, which exhibits excellent target DNA-activated trans-cleavage activity under the guidance of a programmable CRISPR RNA (crRNA), has shown great promise in next-generation biosensing technology. However, current CRISPR-Cas12a-based biosensors usually improve sensitivity by the initial nucleic acid amplification, while the distinct programmability and predictability of the crRNA-guided target binding process has not been fully exploited. Herein, we, for the first time, propose a modular and sensitive CRISPR-Cas12a fluorometric aptasensor by integrating an enzyme-free and robust crRNA-mediated catalytic nucleic acid network, namely, Cas12a-CMCAN, in which crRNA acts as an initiator to actuate cascade toehold-mediated strand displacement reactions (TM-SDRs). As a proof of concept, adenosine triphosphate (ATP) was selected as a model target. Owing to the multiturnover of CRISPR-Cas12a trans-cleavage and the inherent recycling amplification network, this method achieved a limit of detection value of 0.16 µM (20-fold lower than direct Cas12a-based ATP detection) with a linear range from 0.30 to 175 µM. In addition, Cas12a-CMCAN can be successfully employed to detect ATP levels in diluted human serum samples. Considering the simplicity, sensitivity, and easy to tune many targets by changing aptamer sequences, the Cas12a-CMCAN sensing method is expected to offer a heuristic idea for the development of CRISPR-Cas12a-based biosensors and unlock its potential for general and convenient molecule diagnostics.

Enhancement of Proton Conductivity Performance in High Temperature Polymer Electrolyte Membrane, Processed the Adding of Pyridobismidazole.

A pyridobisimidazole unit was introduced into a polymer backbone to obtain an increased doping level, a high number of interacting sites with phosphoric acid and simple processibility. The acid uptake of poly(pyridobisimidazole) (PPI) membrane could reach more than 550% (ADL = 22), resulting in high conductivity (0.23 S·cm-1 at 180 °C). Along with 550% acid uptake, the membrane strength still held 10 MPa, meeting the requirement of Proton Exchange Membrane (PEM). In the Fenton Test, the PPI membrane only lost around 7% weight after 156 h, demonstrating excellent oxidative stability. Besides, PPI possessed thermal stability with decomposition temperature at 570 °C and mechanical stability with a glass transition temperature of 330 °C.

Using the Strategy of Inducing and Genetically Transforming Plant Suspension Cells to Produce High Value-Added Bioactive Substances.

Plants can produce many functional bioactive substances. The suspension cell system of plants can be constructed based on its characteristics to realize the large-scale production of valuable products. In this review, we mainly talk about the main strategies, elicitation, and genetic transformation to improve the yield of active substances by using this system. Meanwhile, we focus on the challenges hiding in the practical application and the future prospects and provide new ideas and the theoretical basis for obtaining numerous bioactive substances from plants.

Dispersion-to-localization of catalytic hairpin assembly for sensitive sensing and imaging microRNAs in living cells from whole blood.

Localized DNA circuits have shown good performance regarding reaction rate and sensitivity for sensing intracellular microRNAs (miRNAs). However, these methods reported recently require large kinds of DNA strands and suffer from low signal-to-background (S/B) ratio, which hinder their clinical application. To circumvent these issues, we herein developed a novel strategy for sensitive sensing and imaging miRNAs in living cells based on dispersion-to-localization of catalytic hairpin assembly (DL-CHA). This strategy consists of only three classes of DNA strands (two hairpins and a linker strand), which largely reduces sequence design complexity. Additionally, owing to the unique engineering of the substrate transformation from dispersion to localization, the DL-CHA exhibits not only minimal background leakage but also intensive signal amplification, thus significantly improving the S/B ratio. In particular, the simple sensing method is capable of imaging miRNAs in cells from clinical blood samples for the diagnosis of breast cancer. Therefore, this work provides a powerful tool for intracellular molecules detection and gives a much broader design space for constructing high-performance DNA circuits.

The complete mitochondrial genome of Coccotorusbeijingensis Lin et Li, 1990 (Coleoptera, Curculionidae, Curculioninae, Anthonomini) and its phylogenetic implications.

Coccotorusbeijingensis Lin et Li, 1990 belongs to Coleoptera, Curculionidae, Curculioninae, Anthonomini. It is a herbivorous insect that damages Celtisbungeana Blume (Ulmaceae) by affecting branch growth. The mitochondrial genome of C.beijingensis was sequenced and annotated to better identify C.beijingensis and related species. The total length of the C.beijingensis mitochondrial genome was 17,071 bp, contained 37 typical genes (13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes) and two control regions (total length: 2,292 bp). Mitochondrial genome composition, nucleotide composition and codon usage are similar to those of other sequenced Curculionidae mitogenomes. All protein-coding genes initiated with ATN and TTG codons and ended with TAA, TAG or incomplete stop codons (TA, T). In addition, analyses of pairwise genetic distances between individual PCGs in Curculionidae species showed that ATP8 was the least conserved gene, while COI was the most conserved. Twenty-one transfer RNAs had typical cloverleaf structures, while trnS1 lacked dihydrouridine (DHU) arms. ML and BI analyses, based on 13 PCGs and two rRNAs from ten species of Curculionidae, strongly support the relationships between C.beijingensis and species of the genus Anthonomus: ((An.eugenii+ An.rubi) + C.beijingensis + (An.pomorum+ An.rectirostris)) (BS = 100; PP = 1). Our phylogenetic analyses could mean that the genus Coccotorus should be sunk under Anthonomus, but more taxon sampling is needed to verify this result.