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Recent studies have suggested the glymphatic system as a key mechanism of waste removal in the brain. Dynamic contrast-enhanced MRI (DCE-MRI) using intracisternally administered contrast agents is a promising tool for assessing glymphatic function in the whole brain. In this study, we evaluated the transport kinetics and distribution of three MRI contrast agents with vastly different molecular sizes in mice. Our results demonstrate that oxygen-17 enriched water (H217O), which has direct access to parenchymal tissues via aquaporin-4 water channels, exhibited significantly faster and more extensive transport compared to the two gadolinium-based contrast agents (Gd-DTPA and GadoSpin). Time-lagged correlation and clustering analyses also revealed different transport pathways for Gd-DTPA and H217O. Furthermore, there were significant differences in transport kinetics of the three contrast agents to the lateral ventricles, reflecting the differences in forces that drive solute transport in the brain. These findings suggest the size-dependent transport pathways and kinetics of intracisternally administered contrast agents and the potential of DCE-MRI for assessing multiple aspects of solute transport in the glymphatic system. [ABSTRACT FROM AUTHOR]

Recent studies have suggested the glymphatic system as a key mechanism of waste removal in the brain. Dynamic contrast-enhanced MRI (DCE-MRI) using intracisternally administered contrast agents is a promising tool for assessing glymphatic function in the whole brain. In this study, we evaluated the transport kinetics and distribution of three MRI contrast agents with vastly different molecular sizes in mice. Our results demonstrate that oxygen-17 enriched water (H217O), which has direct access to parenchymal tissues via aquaporin-4 water channels, exhibited significantly faster and more extensive transport compared to the two gadolinium-based contrast agents (Gd-DTPA and GadoSpin). Time-lagged correlation and clustering analyses also revealed different transport pathways for Gd-DTPA and H217O. Furthermore, there were significant differences in transport kinetics of the three contrast agents to the lateral ventricles, reflecting the differences in forces that drive solute transport in the brain. These findings suggest the size-dependent transport pathways and kinetics of intracisternally administered contrast agents and the potential of DCE-MRI for assessing multiple aspects of solute transport in the glymphatic system. [ABSTRACT FROM AUTHOR]

Hydrogels that combine electrical conductivity, mechanical and self‐adhesion properties have attracted considerable interest because of their promising applications in wearable devices and flexible supercapacitors, among others. However, the weak interfacial adhesion between adjacent layers of flexible supercapacitors limits their practical applications. In this work, mussel‐inspired nanocomposite hydrogels composed of tannic acid (TA)‐modified doped polyaniline (PANI) and functional monomer acrylamide (AAm) were prepared, the hydrogel exhibited good mechanical properties (903 % strain at break) and adhesion properties. In a three‐electrode system the hydrogel exhibited a specific capacitance of 851.1 mF cm−2 (at 1 mA cm−2) and good stability. All‐hydrogel supercapacitors with robust interfacial capabilities were assembled on this basis without additional immobilization. The flexible supercapacitors show favorable electrochemical performance (570 mF cm−3 at 1 mA cm−2) and provide a volume energy density 55.9 μWh cm−3 and a capacitance retention of 85.6 % after 2000 cycles. Compared with previous conductive hydrogels, this work will provide a new approach to fabricate nanocomposite hydrogels with self‐adhesive, robust mechanical properties and conductive performance, effectively improving the interfacial adhesion of integrated supercapacitors and expanding the application scope of flexible supercapacitors. [ABSTRACT FROM AUTHOR]

Radio signal recognition has a wide application in future communication systems and the vehicular communication, whose core is the extraction of signal features such as electromagnetic fingerprints. With the rapid development of artificial intelligence technology, deep learning has made amazing breakthroughs in image recognition, speech recognition and other fields. Deep learning is applied to electromagnetic fingerprint extraction in this paper. Firstly, thousands of the downlink aircraft communications addressing and reporting system (ACARS) signals used for communication between civil aircraft and airport tower are collected and generated. Then a pre-transformation network suitable for electromagnetic signals is constructed to convert one-dimensional signals into two-dimensional feature maps, and afterwards the feature maps are input into the convolutional neural network (CNN) for classification. By adopting the attention modules, the classification results were improved by a few percentage points over the baseline with a little cost. The method proposed in this paper achieves an accuracy rate of 94.1% and can obtain the aircraft type in a shorter time than traditional method. Moreover, the robustness of the proposed model in response to additive Gaussian white noise (AWGN) and phase deviation is studied and tested. [ABSTRACT FROM AUTHOR]

Optimizing k-space sampling trajectories is a promising yet challenging topic for fast magnetic resonance imaging (MRI). This work proposes to optimize a reconstruction method and sampling trajectories jointly concerning image reconstruction quality in a supervised learning manner. We parameterize trajectories with quadratic B-spline kernels to reduce the number of parameters and apply multi-scale optimization, which may help to avoid sub-optimal local minima. The algorithm includes an efficient non-Cartesian unrolled neural network-based reconstruction and an accurate approximation for backpropagation through the non-uniform fast Fourier transform (NUFFT) operator to accurately reconstruct and back-propagate multi-coil non-Cartesian data. Penalties on slew rate and gradient amplitude enforce hardware constraints. Sampling and reconstruction are trained jointly using large public datasets. To correct for possible eddy-current effects introduced by the curved trajectory, we use a pencil-beam trajectory mapping technique. In both simulations and in- vivo experiments, the learned trajectory demonstrates significantly improved image quality compared to previous model-based and learning-based trajectory optimization methods for $10\times $ acceleration factors. Though trained with neural network-based reconstruction, the proposed trajectory also leads to improved image quality with compressed sensing-based reconstruction. [ABSTRACT FROM AUTHOR]

Due to the similarity in chemical structure, lignin has presented great potential in the synthesis of bio-based phenolic resin. Herein, a facile and scalable synthesis strategy for a novel cage-like lignin-based phenolic resin was proposed through direct spray drying of the mixture of phenolic resin and unmodified lignin. The as-prepared lignin-based phenolic resin was pre-carbonized and carbonized using KOH to produce mesoporous carbon materials (LPRAC) that were further employed as supercapacitor electrodes. The results revealed that the lignin addition led to the noticeable change of the resin shape from perfect sphere to cage-like structure owing to the surfactivity and hydrophilicity of lignin. The cage-like structure promoted the KOH-activated pore generation and expansion in the carbonization process, resulting in the significantly increased specific surface area of the phenolic carbon and the intensified mesoporous formation. The electrochemical performance determination indicated that the specific capacitance of LPRAC-20% (20% lignin addition) was 217.3 F/g at 0.5 A/g, which was considerably higher than that of the lignin-free phenolic carbon (122.6 F/g). Moreover, the LPRAC-20% also exhibited preferable capacitance retention and excellent cycling stability. Accordingly, the present work offers a simple and scalable approach to prepare cage-like mesoporous carbon with excellent electrochemical performance from lignin-based phenolic resin and thus provides a promising route for lignin valorization in energy storage materials. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, a spherogranular porous composite tin pyrophosphate antimonate (SSbPP) adsorbent was developed for the efficient extraction of rubidium (Rb) and cesium (Cs) resources. This granular composite adsorbent was prepared using the anti-solvent method with polyvinyl chloride (PVC) as carrier and the incorporated SSbPP powder as adsorbent. The composition, molecular structure, and adsorption performance of SSbPP, along with the microstructure and adsorption behavior of the granulated PVC-SSbPP adsorbent, were comprehensively investigated. The results showed that the SSbPP adsorbent with superior performance was synthesized at a Sn:Sb:P molar ratio of 0.5:0.25:2. The adsorption behavior of PVC-SSbPP was evaluated using the pseudo-second-order kinetic model and Langmuir isotherm. The maximal adsorption capacities of PVC-SSbPP for Rb+ and Cs+ were found to be 81.3 mg g−1 and 95.23 mg g−1 at optimal condition, respectively. The PVC-SSbPP also exhibited high adsorption selectivity for Rb+/Cs+ in the presence of competitive metal ions such as K+, Na+, Li+, Mg2+ and Ca2+. Furthermore, through dynamic adsorption-desorption experiment using a fixed-bed column, a low-concentration Rb+/Cs+ solution (10 mg L−1) could be concentrated by approximately 140 times. This research offers a promising approach for the selective extraction of low-concentration Rb and Cs resources from highly saline solutions. [Display omitted] • Tin pyrophosphate antimonate was synthesized for adsorption of Rb and Cs. • Spherogranular porous pyrophosphate composite adsorbent was synthesized. • The adsorption capacity of Rb+ and Cs+ are 81.3 mg g−1 and 95.23 mg g−1 respectively. • Rb+ and Cs+ ions are adsorbed on PVC-SSbPP through proton exchange. • The low-concentration Rb+ and Cs+ in solution can be concentrated by 140 times. [ABSTRACT FROM AUTHOR]

Single-atom catalysts (SACs) with active metals dispersed atomically have shown great potential in heterogeneous catalysis due to the high atomic utilization and superior selectivity/stability. Synthesis of SACs using carbon-neutral biomass and its components as the feedstocks provides a promising strategy to realize the sustainable and cost-effective SACs preparation as well as the valorization of underused biomass resources. Herein, we begin by describing the general background and status quo of carbon-based SACs derived from biomass. A detailed enumeration of the common biomass feedstocks (e.g., lignin, cellulose, chitosan, etc.) for the SACs preparation is then offered. The interactions between metal atoms and biomass-derived carbon carriers are summarized to give general rules on how to stabilize the atomic metal centers and rationalize porous carbon structures. Furthermore, the widespread adoption of catalysts in diverse domains (e.g., chemocatalysis, electrocatalysis and photocatalysis, etc.) is comprehensively introduced. The structure-property relationships and the underlying catalytic mechanisms are also addressed, including the influences of metal sites on the activity and stability, and the impact of the unique structure of single-atom centers modulated by metal/biomass feedstocks interactions on catalytic activity and selectivity. Finally, we end this review with a look into the remaining challenges and future perspectives of biomass-based SACs. We expect to shed some light on the forthcoming research of carbon-based SACs derived from biomass, manifestly stimulating the development in this emerging research area. [Display omitted] • Advances in carbon-based SACs derived from biomass and its components are reviewed. • Unique interactions between metal and biomass for atomic metal dispersion are revealed. • Conformations of active atomic metal on biomass-derived carbon carriers are elaborated. • Applications of biomass-based SACs in diverse catalysis are comprehensively introduced. [ABSTRACT FROM AUTHOR]

Utilization of plastic materials (e.g., polyethylene) in mulching film production has inevitably resulted in non-degradable pollutants in soil, which accordingly promotes the development of biodegradable mulching film industry. As a rich renewable, biodegradable aromatic polymer, Lignin exhibits great potential for fabricating functional biodegradable composite mulching films. In recent years, composite mulching films containing lignin have garnered more interest for both practical applications and fundamental research, but comprehensive reviews detailing preparation and application of this rapidly developing composite are still limited. Herein, we begin with a brief description about the processes used to prepare lignin-based biodegradable mulching film. Furthermore, the design and application advances of lignin-based biodegradable mulching films are elaborated based on the polymer materials used, including natural and synthetic biodegradable polymers. Finally, the remaining challenges and future perspectives of lignin-based biodegradable mulching films are summarized. We expect that this finding will shed light on the forthcoming research of lignin-based biodegradable mulching film, and stimulate the development in this research area. • Design and application of lignin-based biodegradable composite mulching film are reviewed. • Film preparation methods including physical and chemical processing are described individually. • Application progresses of lignin-based mulching film are elaborated based on the polymer used. • Enhancements of composite mulching film properties by lignin addition are emphasized. • Challenges and perspectives of lignin-based biodegradable mulching films are summarized. [ABSTRACT FROM AUTHOR]

Sustainably sourced lignin presents great potential as a green feedstock for fertilizer production but commercial fulfillment is still challenging owing to the mediocre fertilizer activity of lignin. To address this issue, an effective strategy to enhance the activity of lignin-based potassium fertilizer (LPF) is proposed through lignin fractionation. Three lignin fractions subdivided from enzymatic hydrolysis lignin (EHL) were adopted as the feedstock for LPF preparation, and the effect of lignin fractionation on wheat seed germination and seedling growth was investigated. Compared with the potassium fertilizer from unfractionated lignin, LPF-F1 showed significantly improved effects on promoting seed germination and seedling growth, which can be attributed to the high potassium content resulted from its abundant phenolic hydroxyl and carboxyl contents. Under the optimal treatment concentration (100 mg/L), LPF-F1 showed comparable promotion effect to commercial fulvic acid potassium on wheat seedling growth, suggesting the potential of LPF-F1 as commercial potassium fertilizer. Overall, this work reveals that lignin heterogeneity presents critical effects on the wheat seed germination and seedling growth of LPF, and the fertilizer activity of LPF can be substantially improved using fractionated lignin with low molecular weight as the raw material. [Display omitted] [ABSTRACT FROM AUTHOR]

Carbon-supported Ru-based catalysts have shown great potential in the hydrodeoxygenation of biomass-derived chemicals but still suffer from the uneven/unstable metal loading owing to the weak affinity between the metal and the carbon-based support. Herein, novel ultrafine Ru nanoparticles supported on lignin-derived nitrogen-doped carbon layers (Ru/LNC) were prepared through a facile pyrolysis of lignin-Ru complex mixed with melamine and further subjected to the hydrodeoxygenation of levulinic acid (LA) into γ-valerolactone (GVL) using formic acid (FA) as the H-donor. The formation of lignin-Ru complexes and abundant N -anchoring sites collaboratively improve the dispersion of metals, thus forming the ultrafine Ru nanoparticles (∼3 nm). Meanwhile, the base site generated by nitrogen -doping promotes the adsorption of acidic reactants (FA and LA) to improve the catalytic performance. Therefore, Ru/LNC catalyst exhibited outstanding catalytic performance (99.5 % of LA conversion and 98.4 % of GVL yield), which was significantly higher than Ru/LC (without N doping) and Ru/C (fabricated through convention impregnation method). Owing to the strong interaction of N species and Ru nanoparticles, Ru/LNC also exhibited improved reusability. Consequently, this work proposes a novel route to fabricate ultrafine Ru nanoparticles embedded on lignin-derived nitrogen-doping carbon nanolayer and further demonstrates its superior applicability in LA hydrodeoxygenation. [ABSTRACT FROM AUTHOR]

Carbon-supported Ru-based catalysts have shown great potential in the hydrodeoxygenation of biomass-derived chemicals but still suffer from the uneven/unstable metal loading owing to the weak affinity between the metal and the carbon-based support. Herein, novel ultrafine Ru nanoparticles supported on lignin-derived nitrogen-doped carbon layers (Ru/LNC) were prepared through a facile pyrolysis of lignin-Ru complex mixed with melamine and further subjected to the hydrodeoxygenation of levulinic acid (LA) into γ-valerolactone (GVL) using formic acid (FA) as the H-donor. The formation of lignin-Ru complexes and abundant N -anchoring sites collaboratively improve the dispersion of metals, thus forming the ultrafine Ru nanoparticles (∼3 nm). Meanwhile, the base site generated by nitrogen -doping promotes the adsorption of acidic reactants (FA and LA) to improve the catalytic performance. Therefore, Ru/LNC catalyst exhibited outstanding catalytic performance (99.5 % of LA conversion and 98.4 % of GVL yield), which was significantly higher than Ru/LC (without N doping) and Ru/C (fabricated through convention impregnation method). Owing to the strong interaction of N species and Ru nanoparticles, Ru/LNC also exhibited improved reusability. Consequently, this work proposes a novel route to fabricate ultrafine Ru nanoparticles embedded on lignin-derived nitrogen-doping carbon nanolayer and further demonstrates its superior applicability in LA hydrodeoxygenation. [ABSTRACT FROM AUTHOR]

This paper examines a combined supervised-unsupervised framework involving dictionary-based blind learning and deep supervised learning for MR image reconstruction from under-sampled k-space data. A major focus of the work is to investigate the possible synergy of learned features in traditional shallow reconstruction using adaptive sparsity-based priors and deep prior-based reconstruction. Specifically, we propose a framework that uses an unrolled network to refine a blind dictionary learning-based reconstruction. We compare the proposed method with strictly supervised deep learning-based reconstruction approaches on several datasets of varying sizes and anatomies. We also compare the proposed method to alternative approaches for combining dictionary-based methods with supervised learning in MR image reconstruction. The improvements yielded by the proposed framework suggest that the blind dictionary-based approach preserves fine image details that the supervised approach can iteratively refine, suggesting that the features learned using the two methods are complementary. [ABSTRACT FROM AUTHOR]

As the most abundant aromatic biopolymer, lignin presents great potential to produce valuable materials and chemicals. However, its large-scale value-added application is still facing many practical challenges and one of them is the unstable properties caused by lignin heterogeneity. Herein, we developed a novel "one-step-three-fractions" fractionation strategy to reduce lignin heterogeneity using aqueous two-phase system (ATPS) composed of (NH 4) 2 SO 4 and ethanol. In contrast to conventional step-wise fractionation processes, the proposed process subdivided heterogeneous lignin into three homogeneous fractions in only one step: the first fraction (F1) dissolved in the ethanol-rich top layer; the second fraction (F2) dissolved in the salt-rich bottom layer and the last fraction (F3) insoluble in both two layers. F2 presented the lowest molecular weight followed by F1 while F3 showed the highest molecular weight. With the increase of molecular weight, the contents of guaiacyl unit and β-O-4 linkage increased while the content of hydrophilic groups (carboxyl and aromatic hydroxyl) decreased significantly. Moreover, the ATPS exhibited satisfactory recyclability and the fractionation approach could be applied to different types/sources of lignin. Consequently, the work indicates that ATPS is a novel and effective way to fractionate lignin and reduce its molecular weight polydispersity and structural heterogeneity in one step. [Display omitted] • Aqueous two-phase system (ATPS) consisting of (NH 4) 2 SO 4 and ethanol was used for lignin fractionation. • Enzymatic hydrolysis lignin was subdivided into three fractions in only one dissolution step. • The three fractions showed reduced heterogeneity in molecular weight and chemical structure. • The universal fractionation approach can be applied to different types/sources of lignin. • The fractionation using regenerated ATPS demonstrated the satisfactory recyclability. [ABSTRACT FROM AUTHOR]

Different dimensional (0D–3D) carbon materials with tailorable compositions and nanostructures have attracted widespread attention and are promising for a wide range of applications in energy storage, adsorption, and catalysis. Lignin, as a typical renewable, low-cost, highly aromatic, and high carbon content bio-component, presents compelling potential in the preparation of multifunctional carbon materials. Currently, numerous lignin-derived carbon materials in different dimensions have been developed successfully. Moreover, by structural design and surface modification, lignin-derived carbon materials with desirable properties can be obtained. This work presents a comprehensive overview on the preparation techniques employed for lignin-derived carbon materials as well as the configurations and applications of the obtained lignin-derived carbon materials. First, advances in cutting-edge research on the preparation of lignin-derived carbon materials (pyrolysis-activation and template methods) are summarized. When lignin is used as a carbon precursor, carbon materials with different dimensions such as 0D, 1D, 2D, or 3D with complex compositions (e.g., heteroatom doping or metal loading) can be prepared. Additionally, the applications of lignin-derived carbon materials for energy storage, adsorption and catalysis are reviewed. Finally, prospects and potential challenges in designing and developing lignin-derived carbon materials are discussed in depth. [Display omitted] • The main components of lignin are briefly introduced. • The preparation of different dimensions of lignin-derived carbon materials are elaborated. • The prospects and challenges of lignin-derived carbon materials for high-value applications are presented. [ABSTRACT FROM AUTHOR]

Sustainably sourced lignin is a desired precursor for carbon materials due to its cross-clinked aromatic structure and high carbon content. However, the heterogeneity of lignin feedstock presents non-negligible effects on its physicochemical properties and thereby substantially influences its applications in carbon materials fabrication. In this work, fractionation of corn stalk enzymatic hydrolysis lignin via a simple two-step ordinal dissolution was adapted to reduce lignin heterogeneity and further improve the microstructure and electrochemical performances of lignin-derived heteroatom-doped carbon materials. The results revealed that the fractionation process successfully obtained three lignin fractions with sequentially increasing molecular weight and specific surface area. When the three lignin fractions were subjected to carbonization/activation to fabricate N/P/S co-doped carbon, the F3-derived carbon material (LC-F3) showed the highest specific surface area (2022.4 m2/g) and the best heteroatom doping effect due to the improved activation process resulted from the largest specific surface area of F3. Moreover, the good thermal stability of F3 also contributed to the maintenance of disordered structure during carbonization. Therefore, LC-F3 exhibited excellent specific capacitance (337.2 F/g, 0.5 A/g) and cycling stability (96.5% after 10,000 cycles) as a consequence of its high disordered level, heteroatom doping density and specific surface area. Consequently, this work systematically evaluates the effects of lignin fractionation on the physicochemical structural and electrochemical performances of the carbon materials and further proposes a simple strategy to enhance electrochemical properties of the heteroatom-doped carbon materials through lignin fractionation. [Display omitted] • Lignin was subdivided into three fractions in two sequential dissolution step. • Fractionation contributes to the formation of pores in lignin. • Heteroatom-doped improves the wettability and introduces the pseudocapacitance. • LC-F3 showed high specific capacitance due to its disordered structure and high S BET. [ABSTRACT FROM AUTHOR]

In this work, sodium lignosulfonate (SL) was introduced in the hydrothermal preparation of phenol-formaldehyde (PF) resin sphere that was subsequently used as a green reducer and support for synthesis of Ag nanoparticles (Ag NPs). The results showed that the addition amount of SL had a remarkable effect on the size of the SL incorporated PF (SLPF) spheres and the smallest particle size was obtained when 20% of SL (based on phenol mass) was added. The addition of SL increased the surface area and negative charge of SLPF spheres, which enhanced the Ag NPs loading amount accordingly. Moreover, SL also prevented Ag NPs from aggregating effectively, resulting in the high-density loading of small size Ag NPs on the SLPF spheres. Therefore, the as-prepared Ag@SLPF composites exhibited significantly enhanced catalytic activities in the 4-nitrophenol reduction than that of SL-free Ag@PF. Besides, the Ag@SLPF catalyst demonstrated superior recyclability owing to strong anchoring between the Ag NPs and the support. Consequently, the work demonstrates the incorporation of SL enables the green formation of high-density and tunable Ag NPs on the SLPF support and then endows the composite catalyst with enhanced catalytic performance, which presents a promising value-added application of lignosulfonate for functional catalyst preparation. Unlabelled Image • The addition of sodium lignosulfonate (SL) decreases the size of SLPF spheres significantly. • SL enhances the adsorption amount of Ag+ on SLPF spheres, resulting in high-density loading of Ag NPs. • SL prevents the aggregation of Ag NPs effectively, leading to the formation of small Ag NPs. • SL incorporation enables the formation of high-density and small Ag NPs on SLPF support. • The as-prepared Ag@SLPF exhibited significantly enhanced catalytic activities compared with the SL-free Ag@PF. [ABSTRACT FROM AUTHOR]

Lignin nanosizing has received much interest as it offers new potential for value-added applications of the currently under-utilized lignin biopolymers. However, conventional lignin nanosizing technologies often rely on the use of large amounts of toxic organic solvents, and a time-consuming dialysis process that is required to remove the solvents. Herein, we present a novel and effective approach using a binary system consisting of green γ-valerolactone (GVL) and glycerol solvents to prepare lignin nanospheres (LNS) without lignin modification and additional dialysis processes. The rationale of LNS formation lies in the emulsification of uniform lignin-containing GVL droplets in glycerol by a process consisting of (1) heating to 80 °C, and (2) cooling to room temperature. Through this simple process, we obtained very high LNS yield (over 90%), with narrow size distribution (about 275 nm) by using maple kraft lignin as the raw material. This lignin nanosizing approach is universal when applied to different sources/types of lignins. The as-prepared LNS were further applied as a green reducing agent and carrier for the synthesis of Pd nanoparticles (NPs) in a facile in situ reduction process. Pd@LNS exhibited significantly enhanced catalytic capacity in the hydrogen evolution from formic acid and in the reduction of Cr(VI) to Cr(III) compared with bare Pd NPs. The Pd@LNS catalyst demonstrated high recyclability owing to the good chemical stability of LNS and robust loading of Pd NPs on LNS. Consequently, this work offers a green, universal and effective approach for LNS fabrication and presents a promising application of LNS as metal NP carriers for catalysis purposes. [ABSTRACT FROM AUTHOR]

Multi-echo saturation recovery sequence can provide redundant information to synthesize multi-contrast magnetic resonance imaging. Traditional synthesis methods, such as GE’s MAGiC platform, employ a model-fitting approach to generate parameter-weighted contrasts. However, models’ over-simplification, as well as imperfections in the acquisition, can lead to undesirable reconstruction artifacts, especially in T2-FLAIR contrast. To improve the image quality, in this study, a multi-task deep learning model is developed to synthesize multi-contrast neuroimaging jointly using both signal relaxation relationships and spatial information. Compared with previous deep learning-based synthesis, the correlation between different destination contrast is utilized to enhance reconstruction quality. To improve model generalizability and evaluate clinical significance, the proposed model was trained and tested on a large multi-center dataset, including healthy subjects and patients with pathology. Results from both quantitative comparison and clinical reader study demonstrate that the multi-task formulation leads to more efficient and accurate contrast synthesis than previous methods. [ABSTRACT FROM AUTHOR]

As the most abundant aromatic biopolymer, lignin has great potential to replace petroleum-based phenol to prepare phenolic resins (e.g. phenolic adhesive and foam). In this work, a novel lignin-functionalized phenolic resin (LPR) nanosphere was synthesized using a simple hydrothermal curing process and was further used as both a green reducing agent and a support for the formation of Ag nanoparticles (NPs). Interestingly, it was found that the incorporation of lignin into the phenolic resin (PR) decreased its size from microscale to nanoscale due to the surface activity of lignin. Besides, a part of lignin (the uncombined lignin) acted as a sacrificial template to increase the surface roughness of nanospheres. A decrease in the support size and an increase in the surface roughness enhanced the specific surface area of LPR nanospheres and the aqueous dispersion stability of LPR@Ag nanocomposites. Owing to the excellent reducing activity of lignin and the enhancement of the specific surface area, the loading amount Ag NPs on LPR nanospheres was considerably higher than on the lignin-free PR microspheres. Accordingly, the LPR@Ag nanocomposites showed excellent capabilities in the catalytic reduction of two typical organic pollutants (anionic methyl orange and cationic methylene blue). Particularly, due to the adsorption of cationic methylene blue by lignin, a synergistic effect of adsorption and catalysis was observed, which considerably improved the catalytic performance of LPR@Ag nanocomposites. LPR@Ag nanocomposites also exhibited good recyclability owing to the stable loading of Ag NPs on the nanosphere support. Finally, this work demonstrates the multifunctionality of lignin as a surfactant, sacrificial template, and green reducing agent in the synthesis of LPR@Ag nanocomposites and therefore, provides a new frontier in the development of lignin-based polymer materials focusing on the synergistic effect of multiple functionalities of lignin. [ABSTRACT FROM AUTHOR]

A series of Dy3+/Eu3+ single‐ and co‐doped calcium borosilicate luminescent glasses were prepared by the conventional high temperature melt‐quenching method. A compact glass structure is obtained by the addition of Dy3+/Eu3+ ions, which is verified by the physical properties of synthetic glasses. As network modifiers, Dy3+/Eu3+ fill in the interspaces of glass network and contribute to the conversion of [BO3] to [BO4]. Dy3+/Eu3+ co‐doped calcium borosilicate glasses can emit white light, which consists of blue, yellow, and red light under 387 nm excitation. The emission spectra and decay curves of the white‐emitting glasses have proved the existence of energy transfer. The average lifetime of Dy3+ decreases from 0.251 to 0.165 ms with the increasing Eu3+ concentration. Changing rare earth ions concentration, CIE color coordinates of Dy3+/Eu3+ co‐doped glass shifts from cyan to white with increasing excitation wavelength. A white‐light emission is obtained when the concentration of Dy3+ and Eu3+ equals to 4% and 2%, respectively. Moreover, the Dy3+/Eu3+ co‐doped calcium borosilicate glass shows high‐thermal stability and it may be applicable for high‐quality white LEDs based on high power near ultraviolet (n‐UV) LED chip in the future. [ABSTRACT FROM AUTHOR]

• A double network physicochemical nanocomposite gel inhibitor was developed. • Chemical inhibitor was combined with double network gel by grafting reaction. • Functional group analysis proved excellent inhibition effects. • Physical, chemical and composite inhibition mechanism was analyzed. To strengthen the inhibition effect of an inhibitor on spontaneous coal combustion throughout the process, this study used solution polymerization to synthesize hyaluronic acid and polyethylene glycol into a double network gel. The double network gel was grafted with a chemical inhibitor, epigallocatechin gallate, and polymerized with nanomaterial attapulgite to prepare a double network gel composite inhibitor with a whole-process inhibition effect. From the results of the scanning electron microscopy test, we found that the folds and pores on the surface of the inhibitor considerably increased with composite treatment. From the results of thermogravimetric analysis, it was proved that the average increase in each characteristic temperature point of the coal sample was 28.15%. According to the results of differential scanning calorimetry, it was found that the heat release interval of the inhibited sample was narrowed, and the total heat release was reduced by 2408.08 J/g. From the results of gas analysis, it was concluded that the production of CO, CO 2 , and CH 4 by the inhibited sample markedly reduced, which verified the environmental friendliness of the inhibitor. Through a diffuse reflection infrared spectrum test, it was found that the inhibition treatment could deactivate the active groups in coal and increase the content of the ether bonds of the stable functional groups, which proved that the composite inhibitor is an excellent fire prevention material. [ABSTRACT FROM AUTHOR]

Over the recent years, the exploitation of antibacterial performance of lignin and its subsequent usage as bacteriostatic additives has gained increasing interests. However, due to the restriction from structural heterogeneity, the antibacterial activity of lignin is always modest and unstable (especially against Gram-negative bacteria). In this regard, we proposed a facile one-step ethanol fractionation process to decrease the heterogeneity of lignin and, therefore, improve its antibacterial activity. Two fractions (Fs and Fi, 95% ethanol soluble and insoluble fraction, respectively) were obtained from bamboo kraft lignin (BKL) and their antibacterial effectiveness was compared. The results showed that the antibacterial activity of Fs increased significantly compared to that of BKL. On the contrary, Fi barely exhibited inhibitory effect on the growth of two Gram-positive bacteria and even promoted the growth of two Gram-negative bacteria. The much lower phenolic-OH content in Fi was an important reason for the absence of antibacterial activity. Besides, the growth promotion of Gram-negative bacteria by Fi was possibly caused by the formation of insoluble carriers for bacteria growth due to the poor water-solubility of Fi. Accordingly, after the elimination of Fi, the one-step fractionation significantly enhanced the antibacterial activity of lignin against both Gram-positive and Gram-negative bacteria. • Bamboo kraft lignin was subdivided into Fs and Fi by one-step ethanol fractionation. • Fs showed enhanced antibacterial activity compared to bamboo kraft lignin. • Fi barely showed inhibition on bacteria growth, and even promoted bacterial growth. • The antibacterial activity differences between Fs and Fi were elucidated. • One-step ethanol fractionation of lignin is effective to improve antibacterial activity. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the influences of nose shape, impact velocity (8–14 m/s), and impact angle (60°–90°) on cavity dynamics when a projectile enters water. The Froude number, which characters the kinetic energy against gravitational potential, ranges from 280 to 850. It is found that the cavity diameter changes for different nose shapes, and an elongated cavity is achieved as the impact speed increases. The cavity pinch-off phenomenon is characterized. Experimental data reveal that the nose shape, impact velocity, and impact angle change the pinch-off depth and pinch-off time slightly by changing the occurrence time of the surface seal. For blunt nose shapes, greater impact velocity speeds up the surface seal and then quickens the pinch-off, thus reducing both the pinch-off depth and pinch-off time. Generally, the pinch-off depth follows the Fr1/3 law in our experiments. Cavity ripples were observed after pinch-off, and the wavelength, amplitude, and rippling frequency were measured. The wavelength of a ripple remains constant throughout, and all ripples are fixed with the experimental frame. The rippling frequencies are approximately identical to the Minnaert frequency. The impact velocity significantly changes the rippling frequency by affecting the radius of the air cavity. [ABSTRACT FROM AUTHOR]

Abstract Valorization of lignin based on its biological activities is always suffering the restriction from lignin heterogeneity, including wide molecular weight distributions and variable functional group contents. In this work, organosolv ethanol lignin (OEL) from corn stalk was divided into four fractions by multiple organic solvent successive extraction and the anti-tyrosinase activities of four obtained fractions were compared to evaluate the effect of lignin heterogeneity on the anti-tyrosinase activity. The characterization revealed that the successive extraction realized the fractionation of the heterogeneous OEL into four relatively homogeneous parts with gradually increasing molecular weight and decreasing phenolic OH content. The enzymatic inhibition study showed that the four fractions exhibited obviously different anti-tyrosinase activities and the dichloromethane fraction had the highest tyrosinase inhibition rate (75.12%, 0.5 mg/mL), whose value was comparable to the positive control p -hydroxybenzaldehyde. Besides, the relationships between the anti-tyrosinase activity and the lignin properties (purity, molecular weight and phenolic OH) were discussed to elucidate the possible formation mechanism of differences among the four lignin fractions in anti-tyrosinase activity. Consequently, these results suggest that lignin heterogeneity has a significant effect on the tyrosinase inhibition rate, and lignin fractionation is an effective way to screen lignin fractions with high anti-tyrosinase activity. Graphical abstract Unlabelled Image Highlights • Four different fractions were obtained by successive extraction using three organic solvents. • F1 with the lowest molecular weight and the highest phenolic OH showed the highest activity. • Inhibition type and mechanism of lignin against tyrosinase were proposed. • Lignin fractionation is effective to screen lignin fractions with high anti-tyrosinase activity. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel magnetic lignin-based core-shell microspheres are fabricated for dye adsorption. • Microspheres are cured using emulsion polymerization at a moderate temperature. • Microspheres have much higher methylene blue adsorption capacity than other lignin-based sorbents. • Functional groups of lignosulfonate preserved after curing contribute to high adsorption capacity. • Microspheres exhibit excellent recycling using magnetic separation and acidic ethanol extraction. Abstract The application of green adsorbents from renewable biomass for dye wastewater treatment has received wide attention in recent years. In this work, novel lignin-based Fe 3 O 4 @lignosulfonate/phenolic core-shell microspheres were fabricated for the first time to remove cationic dyes from aqueous solutions. The emulsion polymerization using p -toluenesulfonic acid as a curing agent was employed to synthesize the microspheres at a moderate temperature. Detailed characterizations were conducted to provide a broad evaluation of the microspheres followed by batch experiments to analyze the methylene blue (as a model cationic dye) adsorption performance. Results showed that lignosulfonate/phenolic shell coated uniformly on the Fe 3 O 4 core to form a well-defined core-shell microsphere. Due to cross-linking by phenolic resin, the lignosulfonate coated on the microspheres is highly insoluble in aqueous solutions at a wide pH range, which is prerequisite for an effective dye adsorption from wastewater. The adsorption study showed that the endothermic adsorption process was completed in 40 min and the adsorption kinetics followed a pseudo-second-order model. The equilibrium data were consistent with the Langmuir equation and the maximum monolayer capacity was 283.6 mg/g, which was much higher than those of most lignins and lignin-rich biomass. After adsorption, the microspheres were recycled and a fast regeneration (<10 min) was achieved using ethanol as a methylene blue extraction solvent. Overall, these results indicate that the novel Fe 3 O 4 @lignosulfonate/phenolic microspheres offer a great potential for removing cationic dyes from wastewater in practical applications. [ABSTRACT FROM AUTHOR]

Highlights • Solid acid catalytic phenolation (SACP) is applied to treat enzymatic hydrolysis lignin (EHL). • EHL is depolymerized significantly during SACP treatment without condensation. • Phenol is incorporated into EHL by a nucleophilic reaction that stops lignin condensation. • Treated EHL shows increased phenolic hydroxyl content and reactivity with formaldehyde. • 50% phenol is substituted by treated EHL to prepare phenolic foam with satisfactory properties. Abstract Lignin valorization offers a significant opportunity for the commercial operation of a cellulosic ethanol-derived biorefinery. In this work, a novel solid acid catalytic phenolation (SACP) process was employed to treat enzymatic hydrolysis lignin (EHL) and the obtained product was further applied to prepare lightweight phenolic foams (ρ = 30–40 kg/m3). The changes of the molecular weight and structure of lignin under the SACP treatment were investigated by GPC, Py-GCMS, and 2D-NMR analyses. The results indicated that under the optimized SACP conditions (140 °C, 4% HZSM-5, and 2 h), the molecular weight (M ¯ w) of EHL sharply decreased from 6695 to 2418 g/mol without condensation. The Py-GCMS and 2D-NMR analyses suggested that phenol was incorporated at the C α position through a nucleophilic reaction and this reaction inhibited the lignin condensation during the acidic treatment. Due to the simultaneous depolymerization and phenolation, the treated lignin showed noticeable increase in phenolic hydroxyl content and reactivity with formaldehyde. The further characterization of lignin-based phenolic foams showed that the treated lignin could replace 50% phenol to prepare phenolic foams with satisfactory thermal insulation and compression strength properties. Consequently, this work demonstrates that SACP is effective to depolymerize and activate lignin for high lignin content phenolic foam preparation and offers a value-added way of lignin application as heat-insulating foam materials. [ABSTRACT FROM AUTHOR]

Antimony is being extensively investigated as anode material for sodium ion batteries (SIBs) due to its appropriate sodium insertion potentials, flat charge-discharge plateau and high sodium storage capacity. However, it suffers from unsatisfied cycling stability originated from the huge volume change during cycling. Herein, hollow NiSb spheres confined by three-dimensional interconnected carbon matrix (NiSb⊂3DCM) are prepared by a cross-linking reaction between Ni 2+ and alginate and a galvanic replacement reaction. Benefiting from its the hollow, porous structure and mechanical buffer provided by Ni and carbon coating, NiSb⊂3DCM electrode can deliver a stable capacity of 366 mAh g −1 with 94.3% capacity retention rate after 400 cycles operated at 1 A g −1 , which is the best cycling performance reported so far for Sb-based alloy anodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reductive fractionation of biomass over monatomic Co SAs-N@LC at milder condition. • Single atom catalyst Co SAs-N@LC was fabricated via facile approach. • High monophenol yield (41.67%) and complete delignification at 160 °C with 0.1% H 2 SO 4. • Xylan was simultaneously hydrolyzed, leaving a cellulose-enriched solid fraction. • Co SAs-N@LC displayed superior hydrogen precipitation ability and good acid stability. Lignin reductive depolymerization via a lignin-first strategy is extremely attractive but practically challenging due to the harsh reaction conditions, such as high temperature and high external H 2 pressure. Herein, we demonstrate a highly efficient acid-assisted reductive fractionation of lignocellulose over a cobalt monatomic catalyst (Co SAs-N@LC) under mild temperature without H 2. The Co SAs-N@LC with a Co-N 4 conformation was fabricated by pyrolyzing phenolic-OH rich lignin-metal complex mixed with melamine. When subjected to poplar reductive fractionation at 160 °C with 0.1% H 2 SO 4 , the Co SAs-N@LC achieved a high monophenol yield of 41.7% with near complete delignification (99.7%), which was credited to the acid-metal synergy on effective lignin depolymerization, more importantly on condensation inhibition. Furthermore, thanks to the acid-catalyzed hydrolysis, xylan was simultaneously liberated, leaving a cellulose-rich fraction as the solid fraction. DFT calculations revealed that the Co-N 4 conformation endowed the catalyst superior hydrogen evolution capacity and the monatomic catalyst showed satisfactory recycling stability due to the acid-resistant N-anchoring and the minimized catalyst fouling. Therefore, this work provides an effective approach for reductive fractionation of lignocellulose under mild conditions, more importantly a total biomass fractionation, through the combined use of atomically dispersed Co catalyst and acid co-catalyst. [ABSTRACT FROM AUTHOR]

The conversion of renewable lignin with low-cost and high carbon content properties into porous carbon materials for supercapacitor applications has caught considerable interest. Herein, two dimensional lignin-derived carbon nanosheets (N-LHPC) with hierarchically porous structures were facilely synthesized via a novel metal-lignin assembly strategy and their performances for supercapacitor applications were investigated. During the carbonization process, the uniformly distributed Zn facilitates the coordinating development of micropores structure and the generated MgO embedded in the carbon matrix acts as a template to produce mesoporous structure after acid washing. Moreover, the melamine addition promotes the development of mesopores by formation of lamellae structure and realizes the N doping in the carbon materials. Therefore, the obtained N-LHPC presents an excellent specific capacitance of 235.75 F/g at 0.5 A/g owing to its hierarchical pore structure as well as the N/O functional groups. Moreover, at the power density of 450 W/kg, the N-LHPC achieves a maximum energy density of 14.75 Wh/kg, showing great application potential in energy storage. The metal-lignin assembly strategy followed by N-doping proposed in this paper provides N-LHPC materials with hierarchical nanostructure, good electron/ion transfer properties, and abundant pseudocapacitive active species, which improve the capacitance performances of the N-LHPC. [Display omitted] • N-LHPC was synthesized by one-pot pyrolysis of metal-lignin complex with melamine. • Metal lignin complexes contribute to the formation of homogeneous pores in carbon. • N/O functional groups improve the wettability and introduce the pseudocapacitance. • N-LHPC showed high specific capacitance due to its nanosheet structure and high S BET. [ABSTRACT FROM AUTHOR]

Sodium ion batteries (SIBs) have been considered as promising alternative to lithium ion batteries (LIBs) for large-scale energy storage. However, their inferior electrochemical performances, especially cyclability and rate capability become the major challenge for further development of SIBs. Herein, Sb/C composite prepared via an efficient and facile method with alginate as precursor has been evaluated as anode material for sodium ion batteries. This method shows unique role in formation of porous Sb/C composite, controlling the particle size and achieving excellent carbon coating. Such a composite demonstrates high specific capacity (423 mAh g −1 at 0.1 A g −1 ), good rate capability (226 mAh g −1 at 15 A g −1 ), and excellent cycle life (81.4% capacity retention for 200 cycles at 2 A g −1 ). The facile synthesis and superior electrochemical performance of the Sb/C composite render it a promising anode material for high-performance SIBs. Furthermore, our study shows a feasible and effective way to prepare transition metal (oxides) and porous carbon nanocomposite for SIBs. [ABSTRACT FROM AUTHOR]

The heterogeneity of lignin chemical structure and molecular weight results in the lignin inhomogeneous properties which also covers the antioxidant performance. In order to evaluate the effects of lignin heterogeneity on its antioxidant activity, four lignin fractions from enzymatic hydrolysis lignin were classified by sequential organic solvent extraction and further evaluated by DPPH (1,1-Diphenyl-2-Picrylhydrazyl) free radical scavenging capacity and reducing power analysis. The characterization including FTIR, 1 H NMR and GPC showed that the fractionation process could effectively separate lignin fractions with distinctly different molecular weight and weaken the heterogeneity of unfractionated lignin. The antioxidant performance comparison of lignin fractions indicated that the dichloromethane fraction (F1) with lowest molecular weight (4585 g/mol) and highest total phenolics content (246.13 mg GAE/g) exhibited the highest antioxidant activity whose value was close to commercial antioxidant BHT (butylated hydroxytoluene). Moreover, the relationship between the antioxidant activity and the structure of lignin was further discussed to elucidate the mechanism of antioxidant activity improvement of lignin fractionation. Consequently, this study suggested that the sequential extraction was an effective way to obtain relatively homogeneous enzymatic hydrolysis lignin fractions which showed the potential for the value-added antioxidant application. [ABSTRACT FROM AUTHOR]

In this work, the alkaline extraction processes of lignin from untreated and steam-exploded corn stalk were compared and the enhanced extraction process was investigated by neutral solvent extraction and structural analysis of lignin. It was found that a first order model could readily simulate the lignin extraction from untreated stalk while it was helpless to describe the enhanced process after steam explosion due to the intense dissolution of lignin at the beginning stage of extraction. The lignin extracted by neutral solvent from ball-milled corn stalk and its structural characterization demonstrated that the poor description of extraction process by a first order model was mainly attributed to the considerable depolymerization during steam explosion. Due to the depolymerization of lignin, the alkaline extraction after steam explosion became the direct dissolution of depolymerized lignin and was successfully simulated by a second-order model. Finally, the activation energy of lignin alkali-extraction decreased 37.78% after steam explosion treatment with 1.8 MPa and 5 min, which indicated that milder extraction conditions were available to extract lignin from steam-exploded corn stalk. This study also provides a basic guidance for delignification approaches of lignocelluloses after steam explosion. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) have received much attention in analytical science for their large langmuir surface and high thermostability. Herein MOF-177-coated solid-phase micro-extraction (SPME) fibers were fabricated on etched stainless steel by an adhensive method, and applied to the enrichment of polychlorinated biphenyls (PCB01, PCB05, PCB29, PCB47, PCB98, PCB154, PCB171, PCB201) and polycyclic aromatic hydrocarbons (ANY, ANA, FLU, PHE, ANT, FLT, PYR) from environmental water samples. Several parameters affecting the extraction efficiency were optimized prior to the gas chromatography-mass spectrometry analysis, including extraction temperature and time, desorption time, stirring rate and salt addition. The results indicated that the coated fiber gave low detection limits (0.69–4.42 ng L −1 ) and good repeatability with the RSD ranging from 1.47% to 8.67% for PCBs and PAHs. The recoveries were between 81.8% and 113% with the spiked level of 10 ng L −1 for the real water samples. Besides, the MOF-177 coated fiber was stable enough over 100 extraction cycles and the RSD for fiber-to- fiber reproducibility was less than 9.82% during the experiment. [ABSTRACT FROM AUTHOR]

Lignin heterogeneity, including molecular weight polydispersity and structural complexity, causes undesirable properties of lignin in its valorization. In this regard, the current work focuses on the effect of lignin heterogeneity on the green synthesis of lignin nanosphere (LNS) supported Pd nanoparticles (Pd@LNS) and their catalytic performance. Three lignin fractions with reduced heterogeneity (F1, F2, and F3) were used for LNS fabrication and the as-prepared LNSs were further applied as carriers for Pd nanoparticles (Pd NPs) synthesized using lignin as an in-situ reducer. It was found that the three LNSs exhibited a gradually decreased particle size from F1 to F3, while all of them revealed improved particle size uniformity compared to that from the initial lignin. Owing to the superior reducing power of F1, the LNS prepared from F1 presented the highest loading amount of Pd NPs among the three LNSs. Moreover, these Pd NPs had the smallest particle size and they were dispersed in a much more uniform way than those on the LNSs from F2 and F3. Therefore, the Pd@LNS prepared from F1 exhibited significantly increased catalytic activity in the Cr(VI) reduction compared with those from F2 and F3, as well as the initial lignin. Consequently, the work implies that lignin heterogeneity has considerable influences on the green formation of Pd NPs on LNS, and the catalytic performance of Pd@LNS can be substantially improved using low molecular weight lignin fraction as the feedstock. [Display omitted] • Effect of lignin heterogeneity on lignin nanosphere supported Pd NPs (Pd@LNS) preparation was studied. • Three fractions with reduced heterogeneity (F1, F2 and F3) were obtained by fractionation of initial lignin. • LNS-F1 showed the highest Pd NPs loading amount among the three LNSs due to high reducing power of F1. • Pd NPs on LNS-F1 showed decreased particle size and their dispersion on LNS-F1 was much more uniform. • Pd@LNS-F1 had markedly higher catalytic activity for Cr(VI) reduction than Pd@LNS-F2 and Pd@LNS-F3. [ABSTRACT FROM AUTHOR]

• This research mainly studied a novel PAM/SA-Ca(OH) 2 composite inhibitor. • Inorganic nanoparticles are combined with polyacrylamide by intercalation method. • Functional group analysis proved excellent inhibition effects. • Physical, chemical and composite inhibition mechanism was analyzed. In order to overcome the short service life of existing inhibitors, the physical inhibitor polyacrylamide (PAM) and the nanomaterial silica aerogel powder (SA) were selected to intercalate a composite inhibitor. The product was a polymer-based composite (PAM/SA). Thereafter, PAM/SA was combined with the chemical inhibitor Ca(OH) 2 to form a polymer-based composite inhibitor. Scanning electron microscopy revealed a significant increase in the number of folds and pores on the surface of PAM/SA. Through differential scanning calorimetry, it can be concluded that the thermal stability of PAM/SA was improved, and its glass transition temperature increased from 159 °C to 197 °C. In a thermogravimetric analysis, all characteristic temperature points of the coal samples treated with a composite inhibitor were found to have increased as compared to those treated with a single inhibitor. The thermogravimetric analysis demonstrated that the optimal ratio of PAM/SA to Ca(OH) 2 was 1:1, and the activation energy of the treated coal sample increased from 326.74 KJ·mol−1 to 510.89 KJ·mol−1. Through infrared spectroscopy, it was found that inhibition treatment can reduce reactive groups, such as hydroxyl and aliphatic hydrocarbons, and increase stable structural ether bonds. The above results show that a polymer-based composite inhibitor prepared using the intercalation method can better inhibit the coal spontaneous combustion. [ABSTRACT FROM AUTHOR]

Phenolic resins (PRs) are being widely used in many fields such as molding plastics, foams, coatings, and semiconductor packaging owing to their good properties including corrosion resistance, heat resistance, flame resistance, and electrical insulation properties. However, the traditional phenolic resins industry depends very heavily on petroleum as a source of phenol raw material, which is under the influence of petroleum reserves. In recent years, many studies have been conducted to develop cheap, abundant, renewable, and high-performance alternatives to phenol for the production of PR. Lignin, as the most abundant natural polyphenol, has similar chemical structures to that of phenol. Lignin has received increasing attention as a potential feedstock for renewable fuels and chemical production. The substitution of lignin for phenol can not only reduce the costs of PRs but also increase their performance, such as low-toxicity residues and environmental friendliness. This paper reviews the recent progress in lignin activation and modification for lignin-based phenolic resin (LPR) synthesis, highlights the different lignin modification methods, compares the performance of different LPR products, and summarizes their applications in adhesives, foams, molding powders, micro/nano-spheres, and other advanced materials. Finally, this review puts forward the current challenges and potential future prospects for LPR materials. [ABSTRACT FROM AUTHOR]

Highlights: [•] Steam explosion decreased carbohydrate content in alkali-extracted lignin solution. [•] Lignin liquor without purification was methylolated under optimized conditions. [•] Methylolated lignin liquor substituted 50% phenolic adhesive with approved properties. [•] FTIR indicated formaldehyde was incorporated to aromatic C5 of G unit by methylolation. [•] Phenolic substitution by lignin from steam-explosion-derived biorefinery is feasible. [ABSTRACT FROM AUTHOR]

Highlights: [•] Sequential dissolution in ethanol–water solvent is applied to fractionate and purify lignin. [•] Different molecular weight lignin shows different solubility in ethanol–water solvent. [•] Three fractions with low, medium and high molecular weight were obtained. [•] Due to absence of harmful and pricy solvent, the work provides a potential lignin fractionation process. [ABSTRACT FROM AUTHOR]

Highlights: [•] A series of Ag–BiOBr x I1−x were prepared by a simple solution route at room temperature. [•] Ag–BiOBr x I1−x complex photocatalysts show composition-dependent property and enhanced photocatalytic activity. [•] The enhanced activity results from the optimum band gap structure and the plasmon resonance absorption of Ag on the surface of photocatalysts. [Copyright &y& Elsevier]

Abstract: The heterogeneity of lignin, especially the wide distribution of molecular weight, restricts the high value-added application of lignin. This work provided a convenient and efficient method to fractionate lignin by gradient acid precipitation. To investigate the acid precipitation performance of lignin with different molecular weight, four alkali-extracted lignin fractions from steam-exploded stalk were obtained from ultrafiltration and subsequently precipitated by acid addition. Results showed that molecular weight had a significant effect on the acid precipitation behaviors of lignin. High molecular weight lignin fractions (20kDa retentate) were precipitated completely at higher pH and had narrow precipitation pH range compared with low molecular weight lignin fractions. The determination of Zeta potential and the particle size of lignin colloid revealed that higher Zeta potential and larger particle size formed by high molecular weight lignin accelerated the precipitation. According to the acid precipitation behaviors of different molecular weight lignin, gradient acid precipitation of lignin at pH 5.3, 4.0 and 2.0 was established and four lignin fractions were obtained. FT-IR and UV analysis showed similar chemical structures among the four fractions and increasing content of acidic groups as the molecular weight decreased. The GPC results indicated that the lignin fractions obtained from gradient acid precipitation showed gradually decreasing molecular weight from 15,099–3053g/mol and significantly decreasing polydispersity. Consequently, the study indicated gradient acid precipitation a convenient and successful technique to fractionate alkali-extracted lignin from steam-exploded stalk. [Copyright &y& Elsevier]

In this work, electrical transport properties and electrochemical hydrogen storage properties of a cubic spinel In4SnS8hierarchical nanostructure were investigated. A simple single layer device exhibits non-linear current–voltage (I–V) characteristics. The detailed electrical transport properties of the sample indicated that the conduction mechanism varied in different external voltage regions. Derived from the typical spinel system of the A[B2]X4(A: Zn, Cu, Sn, B: In, Ga, X: S, Se) ternary chalcogenides, this thiospinel compound also shows high electrochemical hydrogen storage of 127 mAh g−1and its mechanism is discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lignin heterogeneity causes undesirable properties of lignin and limits its valorization. • Fractionation of lignin into homogeneous fractions is effective to reduce lignin heterogeneity. • Formation of lignin heterogeneity based on molecular weight is elucidated. • Lignin fractionation methods are elaborated and their industrial potentials are discussed. • Upgraded valorization using lignin fractions with different molecular weight is reviewed. Conventional pulping processes and emerging lignocellulosic biorefineries provide a large quantity of lignin with heterogeneous characters, including complex chemical structure and polydisperse molecular weight distribution. The heterogeneity causes undesirable properties for down-stream applications, which limit lignin valorization seriously. Fractionation of heterogeneous lignin into several homogeneous fractions is considered as an effective approach to overcome this limitation and realize upgraded lignin valorization. To date, lignin fractionation approaches have been extensively studied and they can be broadly classified into three categories: gradient acid precipitation, step-wise solvent fractionation, and membrane separation with different cut-offs. After fractionation, the obtained lignin fractions with decreased polydispersity exhibit improved molecular weight dependent properties, and thus using them as raw materials for subsequent applications results in the upgradation of lignin valorization. In this work, the formation of lignin heterogeneity based on molecular weight is firstly elucidated, and lignin fractionation approaches are elaborated and their potentials for industrialization are discussed. Finally, the upgraded valorization using lignin fractions with high and low molecular weight is also reviewed comprehensively in this work. [ABSTRACT FROM AUTHOR]

Sevoflurane (SEV) has been found to induce neurotoxicity and cognitive impairment, leading to the development of degenerative diseases. Protein kinase C delta (PRKCD) is upregulated in the hippocampus of SEV-treated mice and may be related to SEV-related neurotoxicity. However, the underlying molecular mechanisms by which SEV mediates neurotoxicity via PRKCD remain unclear. Normal mice and PRKCD knockout (KO) mice were exposed to SEV. Hippocampal neurons were isolated from mice hippocampal tissues. H&E staining was used for pathological morphology of hippocampal tissues, and NISSL staining was used to analyze the number of hippocampal neurons. The mRNA and protein levels were determined using quantitative real-time PCR, western blot, immunofluorescence staining and immunohistochemical staining. The mitochondrial microstructure was observed by transmission electron microscopy. Cell viability was detected by cell counting kit 8 assay, and ferroptosis was assessed by detecting related marker levels. The cognitive ability of mice was assessed by morris water maze test. And the protein levels of PRKCD, ferroptosis-related markers and Hippo pathway-related markers were examined by western bolt. SEV increased PRKCD expression and ferroptosis in hippocampal tissues of mice. Also, SEV promoted mouse hippocampal neuron injury by inducing ferroptosis via upregulating PRKCD expression. Knockout of PRKCD alleviated SEV-induced neurotoxicity and cognitive impairment in mice, and relieved SEV-induced ferroptosis in hippocampal neurons. PRKCD could inhibit the activity of Hippo pathway, and its knockdown also overturned SEV-mediated ferroptosis by activating Hippo pathway. SEV could induce neurotoxicity and cognitive impairment by promoting ferroptosis via inactivating Hippo pathway through increasing PRKCD expression. [Display omitted] • SEV increases PRKCD expression and ferroptosis in hippocampal tissues and neurons. • PRKCD knockout alleviates SEV-induced neurotoxicity by inhibiting ferroptosis. • PRKCD knockdown activates Hippo pathway suppressed by SEV. • SEV promotes ferroptosis by inactivating Hippo pathway via upregulating PRKCD. [ABSTRACT FROM AUTHOR]

[Display omitted] Amorphous solid dispersions (ASDs) represent an important approach for enhancing oral bioavailability for poorly water soluble compounds; however, assuring that these ASDs do not recrystallize to a significant extent during storage can be time-consuming. Therefore, various efforts have been undertaken to predict ASD crystallization levels with kinetic models. However, only limited success has been achieved due to limits on crystal content quantification methods and the complexity of crystallization kinetics. To increase the prediction accuracy, the accelerated stability assessment program (ASAP), employing isoconversion (time to hit a specification limit) and a modified Arrhenius approach, are employed here for predictive shelf-life modeling. In the current study, a model ASD was prepared by spray drying griseofulvin and HPMC-AS-LF. This ASD was stressed under a designed combinations of temperature, relative humidity and time with the conditions set to ensure stressing was carried out below the glass transition temperature (T g) of the ASD. Crystal content quantification method by X-ray powder diffraction (XRPD) with sufficient sensitivity was developed and employed for stressed ASD. Crystallization modeling of the griseofulvin ASD using ASAP prime ® demonstrated good agreement with long-term (40 °C/75 %RH) crystallinity levels and support the use of this type of accelerated stability studies for further improving ASD shelf-life prediction accuracy. [ABSTRACT FROM AUTHOR]

• Anti-tyrosinase activity of hydrolysate obtained from steam exploded corn stalk is evaluated. • Phenolic compounds, especially lignin H-unit monomers are the main tyrosinase inhibitors. • Ethyl-acetate fractionation is used to enrich phenolic compounds and improve the anti-tyrosinase activity. • Ethyl-acetate soluble fraction exhibits better activity than p -coumaric acid (a typical tyrosinase inhibitor). • The work indicates the potential of corn stalk hydrolysate as a value-added tyrosinase inhibitor. In this work, corn stalk was subjected to steam explosion (SE) pretreatment, and the hydrolysate in post-washing liquor of steam exploded corn stalk was assayed for anti-tyrosinase activity for the first time. The hydrolysate showed strong anti-tyrosinase activity with an IC 50 of 2.17 mg/mL (inhibitor concentration when 50% of tyrosinase activity is inhibited) at SE severity of 4.20 (198 °C, 20 min). Through hydrolysate component profiles and model substance analysis, phenolic compounds (especially lignin-derived H-unit monomers and phenolic acids) were confirmed to be the major tyrosinase inhibitors in hydrolysate. To further improve the inhibitory activity, an enrichment process of phenolic compounds by ethyl-acetate fractionation of hydrolysate was employed. Ethyl-acetate soluble fraction exhibited significantly enhanced anti-tyrosinase activity (IC 50 , 0.29 mg/mL), which was even better than p -coumaric acid (a typical tyrosinase inhibitor with IC 50 of 0.31 mg/mL). Additionally, the mixed-type inhibition of hydrolysate on tyrosinase was illustrated by kinetics study and the interaction between hydrolysate and tyrosinase was confirmed by fluorescence quenching measurement. Consequently, this work aims to evaluate and improve the anti-tyrosinase activity of hydrolysate from steam explosion processing of corn stalk, which opens new perspectives in potential application of currently underused corn stalk hydrolysate as a value-added tyrosinase inhibitor. [ABSTRACT FROM AUTHOR]

A kinetic Monte Carlo model of polyurethane polymerization which explicitly tracks the polymer sequences is developed and shared. This model is benchmarked against theoretical and experimental polyurethane data and used to investigate the effect on oligomer distributions of unequal reactivity of the first and second isocyanate to react. The reverse reactions using thermodynamic consistency are then added to the framework, and analogous to the addition polymerization concept of ceiling temperature, equilibrium chain length distributions at various temperatures are calculated. For a mixture of three monomers AA, BB, and CC, where BB and CC do not react with one another, are present in stoichiometric proportions, and have different enthalpies of reaction with AA, an odd‐even effect emerges. Odd length chains are more likely than even length chains for temperatures at which BB and CC have significantly different equilibrium conversions. The concept of ceiling temperature that is typically cited for addition polymers is extended here to provide a measure of conditions under which depolymerization for recycling is favored. [ABSTRACT FROM AUTHOR]

• Novel Pd@LPR catalyst was synthesized by hydrothermal curing and in-situ reduction. • Lignin plays as a surfactant, sacrificial template, and reductant in Pd@LPR synthesis. • Due to multifunction of lignin, more Pd NPs are loaded onto LPR than the lignin-free PR. • Pd@LPR is applied as a highly efficient and reusable catalyst for catalytic reduction of Cr(VI). Lignin, the most abundant aromatic biopolymer, has great potential as a sustainable phenol replacement in phenolic resin synthesis, which has been considered as one of the most promising options for lignin valorization. In this work, kraft lignin from bamboo was used as a phenol substitute for the fabrication of novel lignin-based phenolic resin (LPR) nanosphere using a facile hydrothermal process. The as-prepared LPR nanosphere was then used as a reducing agent and a stabilizing support for synthesis of Pd nanoparticles (NPs). It was found that 40 % replacement of phenol by lignin led to a significant decrease of the nanosphere size and enhancement of the nanosphere surface roughness, which eventually increased the specific surface area of LPR nanosphere. Owing to the enhanced specific surface area and the excellent reducing activity of lignin, the as-prepared LPR nanosphere had considerably higher Pd NPs loading amount compared with the lignin-free PR support. Therefore, the as-prepared Pd@LPR nanocomposites demonstrated highly efficient catalytic ability for the reduction of toxic Cr(VI) and two typical dyes. Moreover, the Pd@LPR nanocomposites exhibited excellent reusability owing to the stable loading of Pd NPs on the lignin-based support. Consequently, the lignin-based nanosphere, prepared by a facile hydrothermal process, is used as a reducing agent and a support for Pd NPs synthesis, which presents a novel approach to develop lignin-functionalized catalyst materials. [ABSTRACT FROM AUTHOR]

Nano-lignin presents great potential in advanced carbon materials preparation since it integrates the advantages of nanomaterials as well the preferable properties of lignin (e.g. high carbon content and highly aromatic structure). Herein, lignin-derived carbon nanosphere supported Pd catalysts (Pd@LCNS) were prepared via a two-step carbonization of Pd2+ adsorbed lignin nanospheres (LNS) and applied in vanillin hydrodeoxygenation. The effect lignin heterogeneity on the synthesis of Pd@LCNS as well as its catalytic performance was further investigated through the synthesis of Pd@LCNS using three lignin fractions with different molecular weight. The results showed that the three Pd@LCNSs exhibited significant differences in the morphology of both carbon support and Pd nanoparticles. Pd@LCNS-3 prepared from high molecular weight lignin fraction (L-3) presented stable carbon nanosphere support with the smallest particle size (∼150 nm) and the highest Pd loading amount (3.78 %) with the smallest Pd NPs size (∼1.6 nm). Therefore, Pd@LCNS-3 displayed superior catalytic activity for vanillin hydrodeoxygenation (99.34 % of vanillin conversion and 99.47 % of 2-methoxy-4-methylphenol selectivity) at 90 °C without H 2. Consequently, this work provides a sustainable strategy to prepare uniformly dispersed lignin-based carbon-supported Pd catalyst using high molecular weight lignin as the feedstock and further demonstrate its superior applicability in the selective transfer hydrogenation of vanillin. [Display omitted] • Pd@LCNS is simply prepared by a two-step carbonization of Pd2+ adsorbed LNS. • Lignin heterogeneity presents critical effect on Pd@LCNS synthesis and catalytic performance. • Pd@LCNS-3 from high molecular weight lignin has the highest Pd loading amount with the smallest size. • Pd@LCNS-3 achieves superior VAN conversion (99.34 %) and MMP selectivity (99.47 %) at mild 90 °C without H 2. • Pd@LCNS-3 showes excellent reusability owing to strong metal-carrier interaction. [ABSTRACT FROM AUTHOR]

[Display omitted] Lignin-derived carbon materials are widely used as electrode materials for supercapacitors. However, the electrochemical performance of these materials is limited by the surface chemistry and pore structure characteristics. Herein, a novel and sustainable strategy was proposed to prepare heteroatom-doped lignin-derived carbon material (Fe-NLC) with well-developed pore size distributions and enhanced graphitization structure via a facile lignin-Fe coordination method followed by carbonization. During carbonization, Fe3+ in lignin-metal complexes evolve into nanoparticles, which act as templates to introduce porous structures in carbon materials. Also, the lignin-Fe coordination structure endows the material with a higher graphitization during carbonization, thereby improving the structural properties of the carbon materials. Due to the removal of Fe 3 O 4 template, the obtained Fe-NLC possessed reasonable pore distribution and nitrigen/oxygen (N/O) functional groups, which can improve the wettability of materials and introduce pseudocapacitance. Accordingly, Fe-NLC possesses a notable specific capacitance of 264 F/g at 0.5 A/g. Furthermore, a symmetric supercapacitor Fe-NLC//Fe-NLC with a high voltage window (1.8 V) was constructed. The symmetric supercapacitor exhibits a maximum energy density of 15.97 Wh/kg at 450 W/kg, demonstrating well application prospects. This paper proposes a novel approach for preparing carbon materials via lignin-metal coordination to provide an alternative way to explore sustainable and low-cost energy storage materials. [ABSTRACT FROM AUTHOR]