Depolymerization of plastics by means of electrified spatiotemporal heating.

Depolymerization is a promising strategy for recycling waste plastic into constituent monomers for subsequent repolymerization1. However, many commodity plastics cannot be selectively depolymerized using conventional thermochemical approaches, as it is difficult to control the reaction progress and pathway. Although catalysts can improve the selectivity, they are susceptible to performance degradation2. Here we present a catalyst-free, far-from-equilibrium thermochemical depolymerization method that can generate monomers from commodity plastics (polypropylene (PP) and poly(ethylene terephthalate) (PET)) by means of pyrolysis. This selective depolymerization process is realized by two features: (1) a spatial temperature gradient and (2) a temporal heating profile. The spatial temperature gradient is achieved using a bilayer structure of porous carbon felt, in which the top electrically heated layer generates and conducts heat down to the underlying reactor layer and plastic. The resulting temperature gradient promotes continuous melting, wicking, vaporization and reaction of the plastic as it encounters the increasing temperature traversing the bilayer, enabling a high degree of depolymerization. Meanwhile, pulsing the electrical current through the top heater layer generates a temporal heating profile that features periodic high peak temperatures (for example, about 600 °C) to enable depolymerization, yet the transient heating duration (for example, 0.11 s) can suppress unwanted side reactions. Using this approach, we depolymerized PP and PET to their monomers with yields of about 36% and about 43%, respectively. Overall, this electrified spatiotemporal heating (STH) approach potentially offers a solution to the global plastic waste problem.

A stable atmospheric-pressure plasma for extreme-temperature synthesis.

Plasmas can generate ultra-high-temperature reactive environments that can be used for the synthesis and processing of a wide range of materials1,2. However, the limited volume, instability and non-uniformity of plasmas have made it challenging to scalably manufacture bulk, high-temperature materials3-8. Here we present a plasma set-up consisting of a pair of carbon-fibre-tip-enhanced electrodes that enable the generation of a uniform, ultra-high temperature and stable plasma (up to 8,000 K) at atmospheric pressure using a combination of vertically oriented long and short carbon fibres. The long carbon fibres initiate the plasma by micro-spark discharge at a low breakdown voltage, whereas the short carbon fibres coalesce the discharge into a volumetric and stable ultra-high-temperature plasma. As a proof of concept, we used this process to synthesize various extreme materials in seconds, including ultra-high-temperature ceramics (for example, hafnium carbonitride) and refractory metal alloys. Moreover, the carbon-fibre electrodes are highly flexible and can be shaped for various syntheses. This simple and practical plasma technology may help overcome the challenges in high-temperature synthesis and enable large-scale electrified plasma manufacturing powered by renewable electricity.

Identification and map-based cloning of an EMS-induced mutation in wheat gene TaSP1 related to spike architecture.

KEY MESSAGE: A candidate gene TaSP1 related to spike shape was cloned, and the gene-specific marker was developed to efficiently track the superior haplotype in common wheat. Spike shape, an important factor that affects wheat grain yield, is mainly defined by spike length (SPL), spikelet number (SPN), and compactness. Zhoumai32 mutant 1160 (ZM1160), a mutant obtained from ethyl methane sulfonate (EMS) treatment of hexaploid wheat variety Zhoumai32, was used to identify and clone the candidate gene that conditioned the spike shape. Genetic analysis of an F2 population derived from a cross of ZM1160 and Bainong207 suggested that the compact spike shape in ZM1160 was controlled by a single recessive gene, and therefore, the mutated gene was designated as Tasp1. With polymorphic markers identified through bulked segregant analysis (BSA), the gene was mapped to a 2.65-cM interval flanked by markers YZU0852 and MIS46239 on chromosome 7D, corresponding to a 0.42-Mb physical interval of Chinese spring (CS) reference sequences (RefSeq v1.0). To fine map TaSP1, 15 and seven recombinants were, respectively, screened from 1599 and 1903 F3 plants derived from the heterozygous F2 plants. Finally, TaSP1 was delimited to a 21.9 Kb (4,870,562 to 4,892,493 bp) Xmis48123-Xmis48104 interval. Only one high-confidence gene TraesCS7D02G010200 was annotated in this region, which encodes an unknown protein with a putative vWA domain. Quantitative reverse transcription PCR (qRT-PCR) analysis showed that TraesCS7D02G010200 was mainly expressed in the spike. Haplotype analysis of 655 wheat cultivars using the candidate gene-specific marker Xg010200p2 identified a superior haplotype TaSP1b with longer spike and more spikelet number. TaSP1 is beneficial to the improvement in wheat spike shape.

Preparation and antibacterial effect of chitooligosaccharides monomers with different polymerization degrees from crab shell chitosan by enzymatic hydrolysis.

This study aimed to explore the structure and antibacterial properties of chitooligosaccharide monomers with different polymerization degrees and to provide a theoretical basis for inhibiting Salmonella infection. Chitosan was used as a raw material to prepare and separate low-molecular-weight chitooligosaccharides. Chitobiose, chitotriose, and chitotetraose were obtained by gradient elution with cation exchange resin. The molecular weights and acetyl groups of the three monomers were determined by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) and nuclear magnetic resonance (NMR), respectively. Three chitooligosaccharide monomers were used to explore the antibacterial effect on Salmonella. The results showed that the degree of deacetylation of chitosan was 92.6%, and the enzyme activity of chitosanase was 102.53 U/g. Within 18 h, chitosan was enzymatically hydrolyzed to chitooligosaccharides containing chitobiose, chitotriose, and chitotetraose, which were analyzed by thin-layer chromatography (TLC) and MALDI-TOF. MALD-TOF and TLC showed that the separation of monomers with ion exchange resins was effective, and NMR showed that there was no acetyl group. Chitobiose had a poor inhibitory effect on Salmonella, and chitotriose and chitotetraose had equivalent antibacterial effects.

A Sustainable Wood-Based Iron Photocatalyst for Multiple Uses with Sunlight: Water Treatment and Radical Photopolymerization.

A sustainable photocatalyst for use with multiple purpose comprising demethylated lignin (Fe3 O4 @D-wood) was made by treatment of wood and iron oxide. Characterization followed by XRD, UV/Vis, photo-current studies, and electrochemical measurements. This material became subject of photocatalytic explorations for water treatment and material synthesis by radical photopolymerization. Exposure of Fe3 O4 @D-wood with artificial sunlight showed an improved activity considering photochemical oxidation of organic pollutants in the presence of H2 O2 . The efficient generation of reactive radicals brought this system also to photopolymerization. Here, radicals based on reactive oxygen species (ROS) generated in the catalytic cycle can be seen as the dominating species to initiate radical polymerization. A mixture of UDMA and TPGDA showed good reactivity with cumene hydroperoxide (CHP). Photocatalyst used for water treatment facilitates reuse for photopolymerization.

Rapid Pressureless Sintering of Glasses.

Silica glasses have wide applications in industrial fields due to their extraordinary properties, such as high transparency, low thermal expansion coefficient, and high hardness. However, current methods of fabricating silica glass generally require long thermal treatment time (up to hours) and complex setups, leading to high cost and slow manufacturing speed. Herein, to obtain high-quality glasses using a facile and rapid method, an ultrafast high-temperature sintering (UHS) technique is reported that requires no additional pressure. Using UHS, silica precursors can be densified in seconds due to the large heating rate (up to 102 K s-1 ) of closely placed carbon heaters. The typical sintering time is as short as ≈10 s, ≈1-3 orders of magnitude faster than other methods. The sintered glasses exhibit relative densities of > 98% and high visible transmittances of ≈90%. The powder-based sintering process also allows rapid doping of metal ions to fabricate colored glasses. The UHS is further extended to sinter other functional glasses such as indium tin oxide (ITO)-doped silica glass, and other transparent ceramics such as Gd-doped yttrium aluminum garnet. This study demonstrates an UHS proof-of-concept for the rapid fabrication of high-quality glass and opens an avenue toward rapid discovery of transparent materials.

Developing Flexible Quinacridone-Derivatives-Based Photothermal Evaporaters for Solar Steam and Thermoelectric Power Generation.

Solar-driven interfacial vaporization by localizing solar-thermal energy conversion to the air-water interface has attracted tremendous attention. In the process of converting solar energy into heat energy, photothermal materials play an essential role. Herein, a flexible solar-thermal material di-cyan substituted 5,12-dibutylquinacridone (DCN-4CQA)@Paper was developed by coating photothermal quinacridone derivatives on the cellulose paper. The DCN-4CQA@Paper combines desired chemical and physical properties, broadband light-absorbing, and shape-conforming abilities that render efficient photothermic vaporization. Notably, synergetic coupling of solar-steam and solar-electricity technologies by integrating DCN-4CQA@Paper and the thermoelectric devices is realized without trade-offs, highlighting the practical consideration toward more impactful solar heat exploitation. Such solar distillation and low-grade heat-to-electricity generation functions can provide potential opportunities for fresh water and electricity supply in off-grid or remote areas.

Quantitative Förster Resonance Energy Transfer: Efficient Light Harvesting for Sequential Photo-Thermo-Electric Conversion.

Light is essential to all life on the earth. Thus, highly efficient light-harvesting systems with the sequential energy transfer process are significant for using solar energy in photosynthesis. For developing an efficient light-harvesting system, a liquid aggregation-induced emission (AIE) dye TPE-EA is obtained, as a donor and solvent, which can light up the aggregation caused quenching (ACQ) Nile Red (NiR, acceptor) to construct a quantitative Förster resonance energy transfer (FRET) system in NiR⊂TPE-EA. Impressively, this FRET pair shows an impressive photothermal effect, producing a peak temperature of 119 °C while excited by UV light, with 37.8% of conversion efficiency. NiR⊂TPE-EA is quite different from most other photothermal materials, which require excitation with long wavelength light (>520 nm). Therefore, NiR⊂TPE-EA firstly converts the solar into thermal energy and then into electric energy to achieve sequential photo-thermo-electric conversion. Such sequential conversion, suitable for being excited by sunlight, is anticipated to unlock new and smart approaches for capturing solar energy.

Estimation of moisture migration in rammed earth based on entropy theory.

In the field of cultural relic protection, the migration of moisture will cause a series of adverse effects, such as disruption and crater eruption. Assessment of water migration status is the key to early warning and prevention of these problems. In an attempt for a solution, the whole process of moisture migration in rammed earth is studied by using the moisture migration initiation criterion based on entropy. We analyzed and compared the entropy change law of the infrared radiation temperature in the two main migration stages, and we made a judgment on whether the moisture state is in the steady equilibrium or in the process of dynamic migration. The results show that the moisture migration status can be identified quickly and in real time by using the moisture migration initiation criterion based on entropy. The results of this study provide a new method for judging the state of moisture migration in geotechnical engineering, especially in the field of cultural relic protection, which has very important practical significance.

Cellulose ionic conductors with high differential thermal voltage for low-grade heat harvesting.

Converting low-grade heat into useful electricity requires a technology that is efficient and cost effective. Here, we demonstrate a cellulosic membrane that relies on sub-nanoscale confinement of ions in oxidized and aligned cellulose molecular chains to enhance selective diffusion under a thermal gradient. After infiltrating electrolyte into the cellulosic membrane and applying an axial temperature gradient, the ionic conductor exhibits a thermal gradient ratio (analogous to the Seebeck coefficient in thermoelectrics) of 24 mV K-1-more than twice the highest value reported until now. We attribute the enhanced thermally generated voltage to effective sodium ion insertion into the charged molecular chains of the cellulosic membrane, which consists of type II cellulose, while this process does not occur in natural wood or type I cellulose. With this material, we demonstrate a flexible and biocompatible heat-to-electricity conversion device via nanoscale engineering based on sustainable materials that can enable large-scale manufacture.

Comparative Transcriptome Analysis of Two Aegilops tauschii with Contrasting Drought Tolerance by RNA-Seq.

As the diploid progenitor of common wheat, Aegilops tauschii is considered to be a valuable resistance source to various biotic and abiotic stresses. However, little has been reported concerning the molecular mechanism of drought tolerance in Ae. tauschii. In this work, the drought tolerance of 155 Ae. tauschii accessions was firstly screened on the basis of their coleoptile lengths under simulated drought stress. Subsequently, two accessions (XJ002 and XJ098) with contrasting coleoptile lengths were selected and intensively analyzed on rate of water loss (RWL) as well as physiological characters, confirming the difference in drought tolerance at the seedling stage. Further, RNA-seq was utilized for global transcriptome profiling of the two accessions seedling leaves under drought stress conditions. A total of 6969 differentially expressed genes (DEGs) associated with drought tolerance were identified, and their functional annotations demonstrated that the stress response was mediated by pathways involving alpha-linolenic acid metabolism, starch and sucrose metabolism, peroxisome, mitogen-activated protein kinase (MAPK) signaling, carbon fixation in photosynthetic organisms, and glycerophospholipid metabolism. In addition, DEGs with obvious differences between the two accessions were intensively analyzed, indicating that the expression level of DEGs was basically in alignment with the physiological changes of Ae. tauschii under drought stress. The results not only shed fundamental light on the regulatory process of drought tolerance in Ae. tauschii, but also provide a new gene resource for improving the drought tolerance of common wheat.

Molecular characterization, expression analysis, and bactericidal activity of the derivative peptides of TFPI-1 and TFPI-2 in half-smooth tongue sole, Cynoglossus semilaevis.

Tissue factor pathway inhibitors (TFPIs) are Kunitz-type serine protease inhibitors that reversibly regulate the blood coagulation induced by tissue factor. TFPI family contain two members, TFPI-1 and TFPI-2. Recent studies have shown TFPI-1 and TFPI-2 also play important roles in innate immunity, however, the potential function of teleost TFPI are very limited. In this study, we characterized two TFPI (CsTFPI-1 and CsTFPI-2) molecules from half-smooth tongue sole (Cynoglossus semilaevis), examined their tissue distributions and expression patterns under pathogens stimulation as well as investigated the antibacterial activity of the C-terminal peptides. Quantitative real time RT-PCR analysis showed that constitutive CsTFPI-1 expression occurred, in increasing order, in head kidney, intestine, brain, spleen, liver, skin, gills, heart, and muscle; CsTFPI-2 was expressed, in increasing order, in the gills, intestine, skin, head kidney, liver, brain, spleen, muscle, and heart. Under Vibrio anguillarum, Streptococcus agalactiae and fish megalocytivirus stimulation, both CsTFPI-1 and CsTFPI-2 expression increased significantly in a manner that depended on the pathogen, tissue type, and infection stage, which suggested CsTFPI-1 and CsTFPI-2 play important roles in anti-bacterial and anti-viral infection. Finally, C-terminal peptides of CsTFPI-1 and CsTFPI-2, were synthesized and proved to have antibacterial effect against Micrococcus luteus that were independent of host serum. Take together, these results indicate that CsTFPI-1 and CsTFPI-2 play important roles in antimicrobial immunity of this fish.

A C-type lectin that inhibits bacterial infection and facilitates viral invasion in black rockfish, Sebastes schlegelii.

C-type lectins (CTLs) are important pattern recognition receptors (PRRs) that play vital roles in innate immunity. In teleosts, a number of CTLs have been reported, but their in vivo effects on host defense are still limited. In this study, a CTL homolog (SsLec1) was identified from black rockfish, Sebastes schlegelii, and its structure, expression and biological function was analyzed. The open reading frame of SsLec1 is 633 bp, with a 5'- untranslated region (UTR) of 36 bp and a 3'- UTR of 117 bp. The deduced amino acid sequence of SsLec1 shares the highest overall identity (73.20%) with the CTL of Oplegnathus fasciatus. SsLec1 possesses conserved CTL features, including a carbohydrate-recognition domain, four disulfide bond-forming cysteine residues, the mannose-type carbohydrate-binding motif, the conserved calcium binding sites and a putative signal peptide. The expression of SsLec1 was highest in liver and could be induced by experimental infection with Listonella anguillarum. Recombinant SsLec1 (rSsLec1) purified from E. coli was able to bind and agglutinate the Gram-negative fish pathogens Vibrio ichthyoenteri and Vibrio vulnificus. The agglutinating ability of rSsLec1 was abolished in the presence of mannose or ethylenediaminetetraacetic acid. Further analysis showed that rSsLec1 could enhance phagocytosis by macrophages. In vivo experiments indicated that rSsLec1 could inhibit bacterial infection and promote viral invasion. Taken together, these results suggest that SsLec1 is a novel CTL that possesses apparent immunoregulation property and plays a critical role in host defense against pathogens invasion.

Isolation of differentially expressed sex genes in garden asparagus using suppression subtractive hybridization.

Garden asparagus (Asparagus officinalis L.) is a dioecious species whose male and female flowers are found in separate unisexual individuals. A region called the M-locus, located on a pair of homomorphic sex chromosomes, controls sexual dimorphism in asparagus. To date, no sex determining gene has been isolated from asparagus. To identify more genes involved in flower development in asparagus, subtractive hybridization library of male flowers in asparagus was constructed by suppression subtraction hybridization. A total of 107 expressed sequence tags (ESTs) were identified. BLASTX analysis showed that the library contained several genes that could be related to flower development. The expression patterns of seven selected genes believed to be involved in the development of asparagus male flower were further analyzed by semi-quantitative or real-time reverse-transcription polymerase chain reaction (RT-PCR). Results showed that AOEST4-5, AOEST12-40, and AOEST13-38 were strongly expressed in the male flower stage, whereas no transcript level of AOEST13-38 was detected in the female flower stage. The expression levels of AOEST13-87, AOEST13-92, AOEST13-40, and AOEST18-87 in the male flower stage were also higher than those in the female flower stage, although these transcripts were also expressed in other tissues. The identified genes can provide a strong starting point for further studies on the underlying molecular differences between the male and female flowers of asparagus.

NFMPAtt-Unet: Neighborhood Fuzzy C-means Multi-scale Pyramid Hybrid Attention Unet for medical image segmentation.

Medical image segmentation is crucial for understanding anatomical or pathological changes, playing a key role in computer-aided diagnosis and advancing intelligent healthcare. Currently, important issues in medical image segmentation need to be addressed, particularly the problem of segmenting blurry edge regions and the generalizability of segmentation models. Therefore, this study focuses on different medical image segmentation tasks and the issue of blurriness. By addressing these tasks, the study significantly improves diagnostic efficiency and accuracy, contributing to the overall enhancement of healthcare outcomes. To optimize segmentation performance and leverage feature information, we propose a Neighborhood Fuzzy c-Means Multiscale Pyramid Hybrid Attention Unet (NFMPAtt-Unet) model. NFMPAtt-Unet comprises three core components: the Multiscale Dynamic Weight Feature Pyramid module (MDWFP), the Hybrid Weighted Attention mechanism (HWA), and the Neighborhood Rough Set-based Fuzzy c-Means Feature Extraction module (NFCMFE). The MDWFP dynamically adjusts weights across multiple scales, improving feature information capture. The HWA enhances the network's ability to capture and utilize crucial features, while the NFCMFE, grounded in neighborhood rough set concepts, aids in fuzzy C-means feature extraction, addressing complex structures and uncertainties in medical images, thereby enhancing adaptability. Experimental results demonstrate that NFMPAtt-Unet outperforms state-of-the-art models, highlighting its efficacy in medical image segmentation.

Study on numerical simulation and mechanical properties of anchor cable with C-shaped tube subjected to shearing.

To examine the disparity in deformation behavior and mechanical qualities between anchor cables with C-shaped tubes and regular anchor cables under shear conditions. The double-sided shear tests of free-section anchor cables and anchor cables with C-shaped tubes were conducted utilizing the indoor large-scale double-shear test equipment with varying pretension loads. The indoor double-shear tests indicate that the inclusion of the C-shaped tube alters the stress distribution of the anchor cables inside the anchor cables with C-shaped tubes and mitigates the impact of stress concentration. Moreover, it facilitates the transition of the anchor cable's failure mode from a mix of tensile and shear breaking to mainly tensile breakage. In addition, ABAQUS finite element analysis software was used to establish a double shear test model of the anchor cable with C-shaped tube to accurately simulate the interaction and stress distribution among the anchor cable, C-shaped tube, and concrete block in the double shear test. The findings of the simulation results reveal that the numerical model can adequately depict the evolution of the stress distribution in the prestressed anchored structure and the damage of the concrete block with increasing shear displacement. The relational equation for the yield state of the anchor cable with C-shaped tube under combined tensile and shear loads is found by integrating the experimental and simulation data, the static beam theory, and the concept of minimal potential energy.

Flash heating process for efficient meat preservation.

Maintaining food safety and quality is critical for public health and food security. Conventional food preservation methods, such as pasteurization and dehydration, often change the overall organoleptic quality of the food products. Herein, we demonstrate a method that affects only a thin surface layer of the food, using beef as a model. In this method, Joule heating is generated by applying high electric power to a carbon substrate in <1 s, which causes a transient increase of the substrate temperature to > ~2000 K. The beef surface in direct contact with the heating substrate is subjected to ultra-high temperature flash heating, leading to the formation of a microbe-inactivated, dehydrated layer of ~100 µm in thickness. Aerobic mesophilic bacteria, Enterobacteriaceae, yeast and mold on the treated samples are inactivated to a level below the detection limit and remained low during room temperature storage of 5 days. Meanwhile, the product quality, including visual appearance, texture, and nutrient level of the beef, remains mostly unchanged. In contrast, microorganisms grow rapidly on the untreated control samples, along with a rapid deterioration of the meat quality. This method might serve as a promising preservation technology for securing food safety and quality.

Discovery of HPG1860, a Structurally Novel Nonbile Acid FXR Agonist Currently in Clinical Development for the Treatment of Nonalcoholic Steatohepatitis.

The farnesoid X receptor (FXR) is a ligand-activated nuclear receptor. Activation of FXR significantly impacts the expressions of the pivotal genes involved in bile acid metabolism, inflammation, fibrosis, and homeostasis of lipid and glucose, leading to considerable interests in developing FXR agonists for the treatment of nonalcoholic steatohepatitis (NASH) or other FXR-relevant diseases. Herein, we describe the design, optimization, and characterization of a series of N-methylene-piperazinyl derivatives as the nonbile acid FXR agonists. Particularly, compound 23 (HPG1860), a potent full FXR agonist, shows high selectivity, favorable ADME and pharmacokinetics profile, along with favorable in vivo activities demonstrated in both rodent PD model and HFD-CCl4 model and is currently in clinical development in patients with NASH in phase II.

A solution-processed radiative cooling glass.

Passive daytime radiative cooling materials could reduce the energy needed for building cooling up to 60% by reflecting sunlight and emitting long-wave infrared (LWIR) radiation into the cold Universe (~3 kelvin). However, developing passive cooling structures that are both practical to manufacture and apply while also displaying long-term environmental stability is challenging. We developed a randomized photonic composite consisting of a microporous glass framework that features selective LWIR emission along with relatively high solar reflectance and aluminum oxide particles that strongly scatter sunlight and prevent densification of the porous structure during manufacturing. This microporous glass coating enables a temperature drop of ~3.5° and 4°C even under high-humidity conditions (up to 80%) during midday and nighttime, respectively. This radiative "cooling glass" coating maintains high solar reflectance even when exposed to harsh conditions, including water, ultraviolet radiation, soiling, and high temperatures.

Ultrahigh-temperature melt printing of multi-principal element alloys.

Multi-principal element alloys (MPEA) demonstrate superior synergetic properties compared to single-element predominated traditional alloys. However, the rapid melting and uniform mixing of multi-elements for the fabrication of MPEA structural materials by metallic 3D printing is challenging as it is difficult to achieve both a high temperature and uniform temperature distribution in a sufficient heating source simultaneously. Herein, we report an ultrahigh-temperature melt printing method that can achieve rapid multi-elemental melting and uniform mixing for MPEA fabrication. In a typical fabrication process, multi-elemental metal powders are loaded into a high-temperature column zone that can be heated up to 3000 K via Joule heating, followed by melting on the order of milliseconds and mixing into homogenous alloys, which we attribute to the sufficiently uniform high-temperature heating zone. As proof-of-concept, we successfully fabricated single-phase bulk NiFeCrCo MPEA with uniform grain size. This ultrahigh-temperature rapid melt printing process provides excellent potential toward MPEA 3D printing.