Innovative Synthesis of Photo-Responsive, Self-Healing Silicone Elastomers with Enhanced Mechanical Properties and Thermal Stability.

Photo-responsive materials have garnered significant interest for their ability to react to non-contact stimuli, though achieving self-healing under gentle conditions remains an elusive goal. In this research, an innovative and straightforward approach for synthesizing silicone elastomers is proposed that not only self-heal at room temperature but also possess unique photochromic properties and adjustable mechanical strength, along with being both transparent and reprocessable. Initially, aldehyde-bifunctional dithiophene-ethylene molecules with dialdehyde groups (DTEM) and isocyanurate (IPDI) is introduced into the aminopropyl-terminated polydimethylsiloxane (H2N-PDMS-NH2) matrix. Subsequently, palladium is incorporated to enhance coordination within the matrix. These silicone elastomers transition to a blue state under 254 nm UV light and revert to transparency under 580 nm light. Remarkably, they demonstrate excellent thermal stability at temperatures up to 100 °C and show superior fatigue resistance. The optical switching capabilities of the silicone elastomers significantly affect both their mechanical characteristics and self-healing abilities. Notably, the PDMS-DTEM-IPDI-@Pd silicone elastomer, featuring closed-loop photo-switching molecules, exhibits a fracture toughness that is 1.3 times greater and a room temperature self-healing efficiency 1.4 times higher than its open-loop counterparts. This novel photo-responsive silicone elastomer offers promising potential for applications in data writing and erasure, UV protective coatings, and micro-trace development.

Crohn disease but not ulcerative colitis increases the risk of acute pancreatitis: A 2-sample Mendelian randomization study.

Accumulating evidence has indicated an increased risk of acute pancreatitis in individuals with inflammatory bowel disease (IBD); however, the establishment of a clear and direct causal connection between IBD and acute pancreatitis remains uncertain. Utilizing genetic data from publicly accessible genome-wide association studies (GWAS), we conducted a 2-sample MR analysis to identify the associations between IBD, ulcerative colitis (UC), Crohn disease (CD), and acute pancreatitis risk. Rigorous quality control steps ensured the selection of eligible single nucleotide polymorphisms (SNPs) with strong associations to IBD. The primary estimation used the inverse-variance weighted method. We also assessed heterogeneity, potential pleiotropy, and conducted sensitivity analyses. The direction of causality was confirmed using the Steiger test. The MR analysis showed that IBD increased the risk of acute pancreatitis (IVW: OR = 1.032, 95% CI: 1.006-1.06, P = .015). Among the subgroup of IBD, CD (IVW: OR = 1.034, 95% CI: 1.008-1.06, P = .007) indicates a significant increase in the risk of acute pancreatitis compared to UC (IVW: OR = 1.02, 95% CI: 0.99-1.051, P = .189). The MR analysis assessing the association between CD and acute pancreatitis showed no evidence of heterogeneity or horizontal pleiotropy. Likewise, the leave-one-out (LOO) method indicated no significant influence of any individual SNP on the overall findings. In addition, the Steiger direction test revealed that CD was the cause for increased risk of acute pancreatitis, but not vice versa. In summary, this research pioneers in proposing a causal relationship between CD and acute pancreatitis among the European population.

Profiles of Family and School Experiences and Adjustment of Adolescents During the Transition to High School.

Although family and school experiences play an important role in adolescents' adjustment during the transition to high school, most prior studies investigated the effects of these experiences in isolation; their joint implications for both adolescents' concurrent and long-term adjustment outcomes are less clear, and the potential role of individual characteristics within such associations remains understudied. Based on 525 10th graders (Mage = 15.48, SDage = 0.71, 43.6% boys) who participated in a longitudinal study, the present research aimed to identify distinct family and school experience profiles among first-year high school students and examine their associations with adolescents' internalizing problems and externalizing problems, both concurrently and 18 months later. Latent profile analysis revealed four distinctive profiles: thriving, low resources-moderate family risk, developmental stress-high parental conflicts, and developmental stress-high peer victimization profiles. The other three profiles (vs. the thriving profile) reported significantly higher levels of concurrent internalizing problems; while these differences diminished after 18 months. However, the enduring impacts of these profiles on internalizing problems persisted among adolescents with higher levels of environmental sensitivity. Additionally, adolescents characterized by two developmental stress profiles (vs. the thriving profile) exhibited significantly higher levels of externalizing problems both currently and longitudinally. Findings underscore the importance of identifying at-risk populations among adolescents during the transition to high school by including both family and school experiences when examining environmental influence on their adjustment, as well as the necessity to take individual environmental sensitivity into account when examining these associations.

Role of ATF3 triggering M2 macrophage polarization to protect against the inflammatory injury of sepsis through ILF3/NEAT1 axis.

BACKGROUND: Sepsis is a systemic inflammatory response which is frequently associated with acute lung injury (ALI). Activating transcription factor 3 (ATF3) promotes M2 polarization, however, the biological effects of ATF3 on macrophage polarization in sepsis remain undefined. METHODS: LPS-stimulated macrophages and a mouse model of cecal ligation and puncture (CLP)-induced sepsis were generated as in vitro and in vivo models, respectively. qRT-PCR and western blot were used to detect the expression of ATF3, ILF3, NEAT1 and other markers. The phenotypes of macrophages were monitored by flow cytometry, and cytokine secretion was measured by ELISA assay. The association between ILF3 and NEAT1 was validated by RIP and RNA pull-down assays. RNA stability assay was employed to assess NEAT1 stability. Bioinformatic analysis, luciferase reporter and ChIP assays were used to study the interaction between ATF3 and ILF3 promoter. Histological changes of lung tissues were assessed by H&E and IHC analysis. Apoptosis in lungs was monitored by TUNEL assay. RESULTS: ATF3 was downregulated, but ILF3 and NEAT1 were upregulated in PBMCs of septic patients, as well as in LPS-stimulated RAW264.7 cells. Overexpression of ATF3 or silencing of ILF3 promoted M2 polarization of RAW264.7 cells via regulating NEAT1. Mechanistically, ILF3 was required for the stabilization of NEAT1 through direct interaction, and ATF3 was a transcriptional repressor of ILF3. ATF3 facilitated M2 polarization in LPS-stimulated macrophages and CLP-induced septic lung injury via ILF3/NEAT1 axis. CONCLUSION: ATF3 triggers M2 macrophage polarization to protect against the inflammatory injury of sepsis through ILF3/NEAT1 axis.

CircEXOC5 Aggravates Sepsis-Induced Acute Lung Injury by Promoting Ferroptosis Through the IGF2BP2/ATF3 Axis.

BACKGROUND: Patients with sepsis resulting in acute lung injury (ALI) usually have increased mortality. Ferroptosis is a vital regulator in sepsis-induced ALI. Exploring the association of ferroptosis and sepsis-induced ALI is crucial for the management of sepsis-induced ALI. METHODS: Whole blood was collected from sepsis patients. Mice were treated with cecal ligation and puncture (CLP) to model sepsis. Primary murine pulmonary microvascular endothelial cells were treated with lipopolysaccharide as a cell model. Ferroptosis was evaluated by analyzing levels of iron, malonaldehyde, glutathione, nonheme iron, ferroportin, ferritin, and GPX4. Hematoxylin and eosin and Masson's trichrome staining were applied to examine lung injury and collagen deposition. Cell apoptosis was analyzed by caspase-3 activity and TUNEL assays. Gene regulatory relationship was verified using RNA pull-down and immunoprecipitation assays. RESULTS: CircEXOC5 was highly expressed in sepsis patients and CLP-treated mice, in which knockdown alleviated CLP-induced pulmonary inflammation and injury, and ferroptosis. CircEXOC5 recruited IGF2BP2 to degrade ATF3 mRNA. The demethylase ALKBH5 was responsible for circEXOC5 upregulation through demethylation. CircEXOC5 silencing significantly improved sepsis-induced ALI and survival rate of mice by downregulating ATF3. CONCLUSIONS: ALKBH5-mediated upregulation of circEXOC5 exacerbates sepsis-induced ALI by facilitating ferroptosis through IGF2BP2 recruitment to degrade ATF3 mRNA.

Protective role of resilience on the associations between childhood maltreatment and internalising and externalising problems.

Different types of childhood maltreatment have negative effects on individual mental and behavioural outcomes. However, most of previous studies investigated their effects separately. Little is known about the effects of co-occurring maltreatment profiles on adolescents' developmental outcomes and the potential protective factor. The current study sought to identify distinct profiles of childhood maltreatment and examine the effects of profiles of childhood maltreatment on internalising and externalising problems and the protective role of resilience based on two-wave longitudinal data, which was collected from a sample of 670 Chinese adolescents (Mage = 15.50, SDage = 0.75, 48.4% boys). Four profiles of childhood maltreatment, that is, No maltreatment (67.9%), High neglect (23.0%), High abuse and neglect/Low sexual abuse (5.0%), and Multi-maltreatment (4.1%), were identified. Adolescents in High neglect, High abuse and neglect/Low sexual abuse, and Multi-maltreatment profiles were more likely to report internalising and externalising problems. Further, significant moderating effects of resilience only emerged for the association between the High neglect profile and internalising problems, such that high levels of resilience may weaken the association between the High neglect profile and internalising problems. Our findings revealed the importance and utility of identifying maltreatment profiles to tailor treatment based on specific maltreatment experiences. Resilience-oriented intervention could be considered for Chinese adolescents who have experienced high neglect.

Design of High-Entropy Tape Electrolytes for Compression-Free Solid-State Batteries.

Advanced solid electrolytes with strong adhesion to other components are the key for the successes of solid-state batteries. Unfortunately, traditional solid electrolytes have to work under high compression to maintain the contact inside owing to their poor adhesion. Here, a concept of high-entropy tape electrolyte (HETE) is proposed to simultaneously achieve tape-like adhesion, liquid-like ion conduction, and separator-like mechanical properties. This HETE is designed with adhesive skin layer on both sides and robust skeleton layer in the middle. The significant properties of the three layers are enabled by high-entropy microstructures which are realized by harnessing polymer-ion interactions. As a result, the HETE shows high ionic conductivity (3.50 ± 0.53 × 10-4 S cm-1 at room temperature), good mechanical properties (toughness 11.28 ± 1.12 MJ m-3, strength 8.18 ± 0.28 MPa), and importantly, tape-like adhesion (interfacial toughness 231.6 ± 9.6 J m-2). Moreover, a compression-free solid-state tape battery is finally demonstrated by adhesion-based assembling, which shows good interfacial and electrochemical stability even under harsh mechanical conditions, such as twisting and bending. The concept of HETE and compression-free solid-state tape batteries may bring promising solutions and inspiration to conquer the interface challenges in solid-state batteries and their manufacturing.

Architecting the Microenvironment Skeleton of Active Materials in High-Capacity Electrodes by Self-Assembled Nano-Building Blocks.

In analogy to the cell microenvironment in biology, understanding and controlling the active-material microenvironment (ME@AM) microstructures in battery electrodes is essential to the successes of energy storage devices. However, this is extremely difficult for especially high-capacity active materials (AMs) like sulfur, due to the poor controlling on the electrode microstructures. To conquer this challenge, here, a semi-dry strategy based on self-assembled nano-building blocks is reported to construct nest-like robust ME@AM skeleton in a solvent-and-stress-less way. To do that, poly(vinylidene difluoride) nanoparticle binder is coated onto carbon-nanofibers (NB@CNF) via the nanostorm technology developed in the lab, to form self-assembled nano-building blocks in the dry slurry. After compressed into an electrode prototype, the self-assembled dry-slurry is then bonded by in-situ nanobinder solvation. With this strategy, mechanically strong thick sulfur electrodes are successfully fabricated without cracking and exhibit high capacity and good C-rate performance even at a high AM loading (25.0 mg cm-2 by 90 wt% in the whole electrode). This study may not only bring a promising solution to dry manufacturing of batteries, but also uncover the ME@AM structuring mechanism with nano-binder for guiding the design and control on electrode microstructures.

Manipulating the Nanophase Separation of a Polymer-Salt Microfluid Generates an Advanced In Situ Separator for Component-Integrated Energy Storage Devices.

A polymer separator plays a pivotal role in battery safety, overall electrochemical performance, and cell assembly process. Traditional separators are separately produced from the electrodes and dominated by porous polyolefin thin films. In spite of their commercial success, today's separators are facing growing challenges with the increasing demand on the device safety and performance. As an attempt to address this urgent need, here, we propose a concept of in situ separator technology by manipulating the two-dimensional (2D) microfluid nanophase separation (2D-MFPS) of a poly(vinylidene difluoride)/lithium salt solution during drying. Particularly, nanophase separation is effectively regulated by low humidity, salt type, and compositions. For application studies, this 2D-MFPS is directly performed onto commercial electrodes under drying conditions with low humidity to fabricate a high-performance in situ separator with thickness and porous structures comparable to those of commercial Celgard separators. This in situ separator shows superior performance in high-temperature stability and wetting capability to a variety of liquid electrolytes. Finally, pouch cells with this in situ separator technology are successfully assembled with an extremely simplified separator-stacking-free process and demonstrate stable cycle performance due to the well-controlled porous structures and electrode-separator interface.

"Sandwich-like" structure electrostatic spun micro/nanofiber polylactic acid-polyvinyl alcohol-polylactic acid film dressing with metformin hydrochloride and puerarin for enhanced diabetic wound healing.

A diabetic wound is a typical chronic wound with a long repair process and poor healing effects. It is an effective way to promote diabetic wound healing to design electrospinning nanofiber films with drug-assisted therapy, good air permeability and, a multilayer functional structure. In this paper, a diabetic wound dressing with a "sandwich-like" structure was designed. Metformin hydrochloride, loaded in the hydrophilic PVA inner layer, could effectively promote diabetic wound healing. The drug release was slowed down by osmosis. The laminate film dressing had good mechanical properties, with tensile strength and elongation at break reaching 5.91 MPa and 90.47 %, respectively, which was close to human skin. The laminate film loaded with erythromycin and puerarin in the hydrophobic PLA outer layer had good antibacterial properties. In addition, due to the high specific surface of the electrostatic spun film, it exhibited high water vapor permeability. It facilitates the gas exchange between the wound and the outside world. The cell experiments proved that the laminate film dressing had good biocompatibility. There was no toxic side effect on cell proliferation. In the diabetic animal wound model, it was shown that the closure rate of diabetic wound repair by laminate film reached 91.11 % in the second week. Our results suggest that the "sandwich-like" nanofiber film dressing could effectively promote the healing process and meet the various requirements of diabetic wound dressing as a promising candidate for future clinical application of chronic wound dressings.

Electrospun polylactic acid nanofiber film modified by silver oxide deposited on hemp fibers for antibacterial fruit packaging.

Bacterial and fungal contamination have become major factors in fruit spoilage and damage, posing a potential risk to human health. In this work, polylactic acid (PLA) nanofibers combined with Ag2O-hemp fibers for a good antimicrobial effect were developed and applied to antimicrobial fruit fresh-keeping packages. The results of molecular simulation calculations showed that the strength of hydrogen bonds between Ag2O and hemp fibers reached 45.522 kJ·mol-1, which proved that Ag2O and with hemp fibers formed a stable deposition. The Ag2O-hemp fibers modified electrospun polylactic acid nanofibrous composite film exhibited favorable mechanical properties. The tensile strength reached 5.23 ± 0.05 MPa and the elongation at break reached 105.56 ± 3.95 %. The obtained nanofibrous composite film has good antibacterial activity against E. coli, S. aureus, A. niger, and Penicillium, which indicated that they could effectively inhibit the growth of bacteria and fungi. The cell experiments proved that the nanofibrous composite film had good biocompatibility with a cell survival rate of 100 %. The experimental results on the fresh-keeping of red grapes showed that the PLA nanofibrous composite film modified by the Ag2O-hemp fibers could effectively prolong the spoilage time of red grapes at room temperature. Compared with the blank group, the freshness period of PLA nanofiber film modified by Ag2O-hemp fibers could be extended for more than 5 days. The hardness of 15 days (1.94 ± 0.19 × 105 Pa) was basically the same as that of 1 day (2.05 ± 0.06 × 105 Pa). The results were superior to commercially available PE preservation films. The above research results indicated that the Ag2O-hemp fibers modified PLA nanofibrous composite film had potential application prospects in the field of fruit fresh-keeping package.

Mass Production of Customizable Core-Shell Active Materials in Seconds by Nano-Vapor Deposition for Advancing Lithium Sulfur Battery.

Rational design and scalable production of core-shell sulfur-rich active materials is vital for not only the practical success of future metal-sulfur batteries but also for a deep insight into the core-shell design for sulfur-based electrochemistry. However, this is a big challenge mainly due to the lack of efficient strategy for realizing precisely controlled core-shell structures. Herein, by harnessing the frictional heating and dispersion capability of the nanostorm technology developed in the authors' laboratory, it is surprisingly found that sulfur-rich active particles can be coated with on-demand shell nanomaterials in seconds. To understand the process, a micro-adhesion guided nano-vapor deposition (MAG-NVD) working mechanism is proposed. Enabled by this technology, customizable nano-shell is realized in a super-efficient and solvent-free way. Further, the different roles of shell characteristics in affecting the sulfur-cathode electrochemical performance are discovered and clarified. Last, large-scale production of calendaring-compatible cathode with the optimized core-shell active materials is demonstrated, and a Li-S pouch-cell with 453 Wh kg-1 @0.65 Ah is also reported. The proposed nano-vapor deposition may provide an attractive alternative to the well-known physical and chemical vapor deposition technologies.

Particulate nitrated aromatic compounds from corn straw burning: Compositions, optical properties and potential health risks.

Nitrated aromatic compounds (NACs) are important components of brown carbon (BrC), and their health and climate effects are of wide concern. Biomass burning is a major contributor to NACs in the atmosphere, yet NACs emitted from biomass burning are poorly constrained. In this study particulate NACs from open burning of corn straws were characterized in terms of their compositions, light absorption and toxic equivalents. 1, 6-dinitropyrene was the most abundant species among the measured nitropolycyclic aromatic hydrocarbons (NPAHs) with a share of 13.4% in total NPAHs, while 4-nitrocatechol was the most abundant nitrophenol (NP) species and accounted for 25.4% of measured NPs. 2-nitropyrene, widely used as a marker of secondary formation of NPAHs, was found to be the second most abundant NPAHs (13.3% of the total NPAHs) in the particulate matter (PM) primarily emitted from corn straw burning, and thus is inappropriate to be an indicator of the secondary formation. The measured primary NACs could only explain a negligible part (0.2%) of the light absorption by BrC. Although the concentrations of 9 toxic NACs were less than one-third of the 16 USEPA priority PAHs, their benzo(a)pyrene toxic equivalency quotients however were approximately 10 times that of the 16 PAHs. This study suggests that in comparison of PAHs from straw burning, NACs should be given greater attention due to their potentially higher toxic effects.

Finite time stable inversion in discrete frequency domain: Accuracy analysis, improvement and application to wafer stage.

Stable inversion represents a classic approach to achieve the exact inverse input for non-minimum-phase (NMP) systems. Solutions deduced based on state-space equations and transfer functions have been frequently proposed, however they are basically developed in the infinite-time horizon and are inherently time-domain computation methods. Considering the practical finite-time tracking tasks, this paper investigates the finite-time stable inversion problem. In particular, the discrete-frequency-domain solution which enables frequency-domain computation is studied. As the main contribution of the paper, the accuracy issues of the discrete-frequency-domain solution are revealed and an easy-to-use procedure is provided to improve the inversion accuracy by utilizing pre-actuation and post-actuation methods. Simulation and experiment both verify the effectiveness of the developed discrete-frequency-domain stable inversion technique.

Biomimetic Microadhesion Guided Instant Spinning.

Animals create high-performance fibers at natural ambient conditions via a unique spinning process. In contrast, the spinning technologies developed by human beings are usually clumsy and require sophisticated skills. Here, inspired by adhesion-based silkworm spinning, we report a microadhesion guided (MAG) spinning technology for instant and on-demand fabrication of micro/nanofibers. Enabled by the adhesion between the spinning fluids and the microneedles, the MAG spinning can generate micro/nanofibers with programmable morphology. By further mimicking the head movement of the silkworm spinning, the MAG technology is extended with three different modes: straight, vibratory, and twisted spinning, which generate oriented fibers, hierarchical cross-linked fibers, and all-in-one fibers, respectively. Due to the prevalence of microadhesion and its unprecedented flexibility in operation, equipment-free MAG spinning is finally realized for instant fiber fabrication by only polymeric foams. Finally, the MAG spinning is demonstrated as a promising instant technology for emergent applications, such as wound dressing.

ABAT gene expression associated with the sensitivity of hypomethylating agents in myelodysplastic syndrome through CXCR4/mTOR signaling.

The factors that affect hypomethylating agents (HMAs) sensitivity in myelodysplastic syndrome (MDS) are complex and multifaceted. They include DNA methylation, gene expression, mutation, etc. However, the underlying mechanisms are still not clearly illustrated. In the present work, ABAT gene expression was associated with HMAs sensitivity. It was found that ABAT gene interference increased the sensitivity of HL-60 and THP-1 cells to HMAs treatment, while ABAT overexpression decreased its sensitivity. RNA-sequencing analysis showed that ABAT knockdown activated both interferon I and interferon-gamma signaling while inhibiting the secondary metabolic synthesis and arginine metabolic process. Gas chromatography-mass spectrometry (GC-MS) based metabolic profiling also demonstrated that ABAT gene knockdown affected arginine, alanine, aspartate, and glutamate metabolism, in addition to the biosynthesis of valine, leucine, and isoleucine, and the metabolism of beta-alanine. The ABAT gene expression downregulation could activate the CXCR4/mTOR signaling pathway, which was related to HMAs sensitivity. CXCR4 expression was regulated by mTOR activity and vice versa. In vivo, mice injected with ABAT gene knockdown cells lived longer than control mice after HMAs treatment. Overall, this study elucidates the novel regulatory mechanisms of HMAs sensitivity and provides a potential therapeutic target in MDS.

Emissions and light absorption of PM2.5-bound nitrated aromatic compounds from on-road vehicle fleets.

Vehicle emissions are an important source of nitrated aromatic compounds (NACs) in particulate size smaller 2.5 µm (PM2.5), which adversely affect human health and biodiversity, especially in urban areas. In this study, filter-based PM2.5 samples were collected during October 14-19, 2019, in a busy urban tunnel (approximately 35,000 vehicles per day) in south China to identify PM2.5-bound NACs. Among them, 2,8-dinitrodibenzothiophene, 3-nitrodibenzofuran and 2-nitrodibenzothiophene were the most abundant nitrated polycyclic aromatic hydrocarbons (NPAHs), while 2-methyl-4-nitrophenol, 2,4-dinitrophenol, 3-methyl-4-nitrophenol and 4-nitrophenol were the most abundant nitrophenols (NPs). The observed mean fleet emission factors (EFs) of NPAHs and NPs were 2.2 ± 2.1 and 7.7 ± 4.1 µg km-1, and were 2.9 ± 2.7 and 10.2 ± 5.4 µg km-1 if excluding electric and liquefied petroleum gas vehicles, respectively. Regression analysis revealed that diesel vehicles (DVs) had NPAH-EFs (55.3 ± 5.3 µg km-1) approximately 180 times higher than gasoline vehicles (GVs) (0.3 ± 0.2 µg km-1), and NP-EFs (120.6 ± 25.8 µg km-1) approximately 30 times higher than GVs (4.1 ± 0.2 µg km-1), and thus 89% NPAH emissions and 56% NP emissions from the onroad fleets were contributed by DVs although DVs only accounted for 3.3% in the fleets. Methanol solution-based light absorption measurements demonstrated that the mean incremental light absorption for methanol-soluble brown carbon at 365 nm was 6.8 ± 2.2 Mm-1, of which the 44 detected NACs only contributed about 1%. The mean EF of the 7 toxic NACs was approximately 3% that of the 16 priority PAHs; However, their benzo(a)pyrene toxic equivalence quotients (TEQBaP) could reach over 25% that of the PAHs. Moreover, 6-nitrochrysene mainly from DVs contributed 93% of the total TEQBaP of the NACs. This study demonstrated that enhancing DV emission control in urban areas could benefit the reduction of exposure to air toxins such as 6-nitrochrysene.

Evolution of light absorption properties during photochemical aging of straw open burning aerosols.

Straw burning comprises more than 30% of all types of burned biomass in Asia, while the estimation of the emitted aerosols' direct radiative forcing effect suffers from large uncertainties, especially when atmospheric aging processes are considered. In this study, the light absorption properties of primary and aged straw burning aerosols in open fire were characterized at 7 wavelengths ranging from 370 nm to 950 nm in a chamber. The primary rice, corn and wheat straw burning bulk aerosols together had a mass absorption efficiency (MAE) of 2.43 ± 1.36 m2 g-1 at 520 nm and an absorption Ångström exponent (AAE) of 1.93 ± 0.71, while the primary sorghum straw burning bulk aerosols were characterized by a relatively lower MAE of 0.95 ± 0.54 m2 g-1 and a higher AAE of 4.80 ± 0.68. Both the MAE and AAE of primary aerosols can be well parameterized by the (PM-BC)/BC ratio (in wt.). The MAE of black carbon (BC) increased by 11-190% during photoreactions equivalent to 16-60 h of atmospheric aging, which was positively correlated with the (PM-BC)/(BC) ratio. The MAE of organic aerosols first slightly increased or leveled off, and then decreased. Specifically, at 370 nm, the first growth/plateau stage lasted until OH exposure reached 0.47-1.29 × 1011 molecule cm-3 s, and the following period exhibited decay rates of 1.0-2.8 × 10-12 cm3 molecule-1 s-1 against the OH radical, corresponding to half-lives of 46-134 h in a typical ambient condition. During photoreactions, competition among the lensing effect, growth/bleach of organic chromophores, and particle mass and size growth complicated the evolution of the direct radiative forcing effect. It is concluded that rice and corn straw burning aerosols maintained a warming effect after aging, while the cooling effect of fresh sorghum straw burning aerosols increased with aging.

Regulating Polysulfide Diffusion and Deposition via Rational Design of Core-Shell Active Materials in Li-S Batteries.

Polar host materials with strong adsorption capacity of polysulfides are designed to limit the shuttle effect in sulfur cathodes. However, a critical problem is to control diffusion and deposition of lithium polysulfides during cycling, which significantly impacts cycling stability and sulfur utilization. Here, we report using a sequential adsorption-guided self-assembly to design two types of core-shell sulfur particles with opposite polysulfide adsorption gradients to explore quantitatively the regulation of polysulfide diffusion and deposition. We show that a positive core-shell design of sulfur particles (PCSD@SP), i.e., polysulfide adsorption capability decreasing from the interior to the exterior of the host, is more effective in restricting polysulfide diffusion and regulating polysulfide deposition than the negative core-shell counterpart (NCSD@SP). As a result, the PCSD@SP electrode with a sulfur loading of 7 mg cm-2 exhibits a stable areal capacity of 6 mAh cm-2 over 130 cycles at 0.2C. At intermittent discharge/charge, the PCSD@SP electrode retains excellent stability compared with the NCSD@SP. We conclude that rational design of positive core-shell active materials can be used to regulate polysulfide diffusion and deposition to boost electrochemical reaction dynamics and performance. The reported findings will be of immediate benefit to a range of researchers in the design of high-performance lithium-sulfur batteries.

Steered polymorphic nanodomains in TiO2 to boost visible-light photocatalytic oxidation.

A breakthrough in enhancing visible-light photocatalysis of wide-bandgap semiconductors such as prototypical titania (TiO2) via cocatalyst decoration is still challenged by insufficient heterojunctions and inevitable interfacial transport issues. Herein, we report a novel TiO2-based composite material composed of in situ generated polymorphic nanodomains including carbon nitride (C3N4) and (001)/(101)-faceted anatase nanocrystals. The introduction of ultrafine C3N4 results in the generation of many oxygen vacancies in the TiO2 lattice, and simultaneously induces the exposure and growth of anatase TiO2(001) facets with high surface energy. The photocatalytic performance of C3N4-induced TiO2 for degradation of 2,4-dichlorophenol under visible-light irradiation was tested, its apparent rate being up to 1.49 × 10-2 min-1, almost 3.8 times as high as that for the pure TiO2 nanofibers. More significantly, even under low operation temperature and after a long-term photocatalytic process, the composite still exhibits exceptional degradation efficiency and stability. The normalized degradation efficiency and effective lifespan of the composite photocatalyst are far superior to other reported modified photocatalysts.