Shining a Light on How Soil Organic Carbon Behaves at Fine Scales under Long-Term Elevated CO2: An 8 Year Free-Air Carbon Dioxide Enrichment Study.

Building and protecting soil organic carbon (SOC) are critical to agricultural productivity, soil health, and climate change mitigation. We aim to understand how mechanisms at the organo-mineral interfaces influence SOC persistence in three contrasting soils (Luvisol, Vertisol, and Calcisol) under long-term free air CO2 enrichment conditions. A continuous wheat-field pea-canola rotation was maintained. For the first time, we provided evidence to a novel notion that persistent SOC is molecularly simple even under elevated CO2 conditions. We found that the elevated CO2 condition did not change the total SOC content or C forms compared with the soils under ambient CO2 as identified by synchrotron-based soft X-ray analyses. Furthermore, synchrotron-based infrared microspectroscopy confirmed a two-dimensional microscale distribution of similar and less diverse C forms in intact microaggregates under long-term elevated CO2 conditions. Strong correlations between the distribution of C forms and O-H groups of clays can explain the steady state of the total SOC content. However, the correlations between C forms and clay minerals were weakened in the coarse-textured Calcisol under long-term elevated CO2. Our findings suggested that we should emphasize identifying management practices that increase the physical protection of SOC instead of increasing complexity of C. Such information is valuable in developing more accurate C prediction models under elevated CO2 conditions and shift our thinking in developing management practices for maintaining and building SOC for better soil fertility and future environmental sustainability.

Formation of soil organic carbon pool is regulated by the structure of dissolved organic matter and microbial carbon pump efficacy: A decadal study comparing different carbon management strategies.

To achieve long-term increases in soil organic carbon (SOC) storage, it is essential to understand the effects of carbon management strategies on SOC formation pathways, particularly through changes in microbial necromass carbon (MNC) and dissolved organic carbon (DOC). Using a 14-year field study, we demonstrate that both biochar and maize straw lifted the SOC ceiling, but through different pathways. Biochar, while raising SOC and DOC content, decreased substrate degradability by increasing carbon aromaticity. This resulted in suppressed microbial abundance and enzyme activity, which lowered soil respiration, weakened in vivo turnover and ex vivo modification for MNC production (i.e., low microbial carbon pump "efficacy"), and led to lower efficiency in decomposing MNC, ultimately resulting in the net accumulation of SOC and MNC. In contrast, straw incorporation increased the content and decreased the aromaticity of SOC and DOC. The enhanced SOC degradability and soil nutrient content, such as total nitrogen and total phosphorous, stimulated the microbial population and activity, thereby boosting soil respiration and enhancing microbial carbon pump "efficacy" for MNC production. The total C added to biochar and straw plots were estimated as 27.3-54.5 and 41.4 Mg C ha-1 , respectively. Our results demonstrated that biochar was more efficient in lifting the SOC stock via exogenous stable carbon input and MNC stabilization, although the latter showed low "efficacy". Meanwhile, straw incorporation significantly promoted net MNC accumulation but also stimulated SOC mineralization, resulting in a smaller increase in SOC content (by 50%) compared to biochar (by 53%-102%). The results address the decadal-scale effects of biochar and straw application on the formation of the stable organic carbon pool in soil, and understanding the causal mechanisms can allow field practices to maximize SOC content.

Inducing Inorganic Carbon Accrual in Subsoil through Biochar Application on Calcareous Topsoil.

Biochar amendments add persistent organic carbon to soil and can stabilize rhizodeposits and existing soil organic carbon (SOC), but effects of biochar on subsoil carbon stocks have been overlooked. We quantified changes in soil inorganic carbon (SIC) and SOC to 2 m depth 10 years after biochar application to calcareous soil. The total soil carbon (i.e., existing SOC, SIC, and biochar-C) increased by 71, 182, and 210% for B30, B60, and B90, respectively. Biochar application at 30, 60, and 90 t ha-1 rates significantly increased SIC by 10, 38, and 68 t ha-1, respectively, with accumulation mainly occurring in the subsoil (below 1 m). This huge increase of SIC (mainly CaCO3) is ∼100 times larger than the inorganic carbon present in the added biochar (0.3, 0.6, or 0.9 t ha-1). The benzene polycarboxylic acid method showed that the biochar-amended soil contained more black carbon particles (6.8 times higher than control soil) in the depth of 1.4-1.6 m, which provided the direct quantitative evidence for biochar migration into subsoil after a decade. Spectral and energy spectrum analysis also showed an obvious biochar structure in the biochar-amended subsoil, accompanied by a Ca/Mg carbonate cluster, which provided further evidence for downward migration of biochar after a decade. To explain SIC accumulation in subsoil with biochar amendment, the interacting mechanisms are proposed: (1) biochar amendment significantly increases subsoil pH (0.3-0.5 units) 10 years after biochar application, thus forming a favorable pH environment in the subsoil to precipitate HCO3-; and (2) the transported biochar in subsoil can act as nuclei to precipitate SIC. Biochar amendment enhanced SIC by up to 80%; thus, the effects on carbon stocks in subsoil must be understood to inform strategies for carbon dioxide removal through biochar application. Our study provided critical knowledge on the impact of biochar application to topsoil on carbon stocks in subsoil in the long term.

Single-shot measurement of the Jones matrix for anisotropic media using four-channel digital polarization holography.

Dynamic measurement of the Jones matrix is crucial in investigating polarization light fields, which have wide applications in biophysics, chemistry, and mineralogy. However, acquiring the four elements of the Jones matrix instantly is difficult, hindering the characterization of random media and transient processes. In this study, we propose a single-shot measurement method of the Jones matrix for anisotropic media called "four-channel digital polarization holography" (FC-DPH). The FC-DPH system is created by a slightly off-axis superposition of reference light waves, which are modulated by a spatial light modulator (SLM), and signal light waves that pass through a Ronchi grating. The SLM enables flexible adjustment of the spatial carrier frequency, which can be adapted to different anisotropic media. The four elements of the Jones matrix can be obtained from the interferogram through the inverse Fourier transform. Optical experiments on anisotropic objects validate the feasibility and accuracy of the proposed method.

A Self-Deoxidizing Electrolyte Additive Enables Highly Stable Aqueous Zinc Batteries.

In aqueous zinc (Zn) batteries, the Zn anode suffers from severe corrosion reactions and consequent dendrite growth troubles that cause fast performance decay. Herein, we uncover the corrosion mechanism and confirm that the dissolved oxygen (DO) other than the reputed proton is a principal origin of Zn corrosion and by-product precipitates, especially during the initial battery resting period. In a break from common physical deoxygenation methods, we propose a chemical self-deoxygenation strategy to tackle the DO-induced hazards. As a proof of concept, sodium anthraquinone-2-sulfonate (AQS) is introduced to aqueous electrolytes as a self-deoxidizing additive. As a result, the Zn anode sustains a long-term cycling of 2500 h at 0.5 mA cm-2 and over 1100 h at 5 mA cm-2 together with a high Coulombic efficiency up to 99.6 %. The full cells also show a high capacity retention of 92 % after 500 cycles. Our findings provide a renewed understanding of Zn corrosion in aqueous electrolytes and also a practical solution towards industrializing aqueous Zn batteries.

A Corrosion-Resistant and Dendrite-Free Zinc Metal Anode in Aqueous Systems.

Rechargeable aqueous zinc (Zn) ion-based energy storage systems have been reviving recently because of their low cost and high safety merits; however, they still suffer from the problems of corrosion and dendrite growth on Zn metal anodes that cause gas generation and early battery failure. Unfortunately, the corrosion problem has not received sufficient attention until now. Here, it is pioneeringly demonstrated that decorating the Zn surface with a dual-functional metallic indium (In) layer, acting as both a corrosion inhibitor and a nucleating agent, is a facile but effective strategy to suppress both drastic corrosion and dendrite growth. Symmetric cells assembled with the treated Zn electrodes can sustain up to 1500 h of plating/stripping cycles with an ultralow voltage hysteresis (54 mV), and a 5000 cycle-life is achieved for a prototype full cell. This work will instigate the further development of aqueous metal-based energy storage systems.

Ultrathin dendrimer-graphene oxide composite film for stable cycling lithium-sulfur batteries.

Lithium-sulfur batteries (Li-S batteries) have attracted intense interest because of their high specific capacity and low cost, although they are still hindered by severe capacity loss upon cycling caused by the soluble lithium polysulfide intermediates. Although many structure innovations at the material and device levels have been explored for the ultimate goal of realizing long cycle life of Li-S batteries, it remains a major challenge to achieve stable cycling while avoiding energy and power density compromises caused by the introduction of significant dead weight/volume and increased electrochemical resistance. Here we introduce an ultrathin composite film consisting of naphthalimide-functionalized poly(amidoamine) dendrimers and graphene oxide nanosheets as a cycling stabilizer. Combining the dendrimer structure that can confine polysulfide intermediates chemically and physically together with the graphene oxide that renders the film robust and thin (<1% of the thickness of the active sulfur layer), the composite film is designed to enable stable cycling of sulfur cathodes without compromising the energy and power densities. Our sulfur electrodes coated with the composite film exhibit very good cycling stability, together with high sulfur content, large areal capacity, and improved power rate.

Building Carbon-Based Versatile Scaffolds on the Electrode Surface to Boost Capacitive Performance for Fiber Pseudocapacitors.

In order to fabricate high performance fiber pseudocapacitors, the trade-off between high mass loading and high utilization efficiency of pseudocapacitive materials should be carefully addressed. Here, a solution that is to construct a carbon-based versatile scaffold is reported for loading pseudocapacitive materials on carbonaceous fibers. The scaffold can be easily built by conformally coating commercial pen ink on the fibers without any destruction to the fiber skeleton. Due to the high electrical conductivity and abundant macropore structure, it can provide sufficient loading room and a high ion/electron conductive network for pseudocapacitive materials. Therefore, their loading mass and utilization efficiency can be increased simultaneously, and thus the as-designed fibrous electrode displays a high areal capacitance of 649 mF cm-2 (or 122 mF cm-1 based on length), which is higher than most of the reported fiber pseudocapacitors. The simple and low-cost strategy opens up a new way to prepare high performance portable/wearable energy storage devices.

Miniaturized optical fiber tweezers for cell separation by optical force.

In advanced biomedicine and microfluidics, there is a strong desire to sort and manipulate various cells and bacteria based on miniaturized microfluidic chips. Here, by integrating fiber tweezers into a T-type microfluidic channel, we report an optofluidic chip to selectively trap Escherichia coli in human blood solution based on different sizes and shapes. Furthermore, we simulate the trapping and pushing regions of other cells and bacteria, including rod-shaped bacteria, sphere-shaped bacteria, and cancer cells based on finite-difference analysis. With the advantages of controllability, low optical power, and compact construction, the strategy may be possibly applied in the fields of optical separation, cell transportation, and water quality analysis.

Strong Metal-Phosphide Interactions in Core-Shell Geometry for Enhanced Electrocatalysis.

Rational design of multicomponent material structures with strong interfacial interactions enabling enhanced electrocatalysis represents an attractive but underdeveloped paradigm for creating better catalysts for important electrochemical energy conversion reactions. In this work, we report metal-phosphide core-shell nanostructures as a new model electrocatalyst material system where the surface electronic states of the shell phosphide and its interactions with reaction intermediates can be effectively influenced by the core metal to achieve higher catalytic activity. The strategy is demonstrated by the design and synthesis of iron-iron phosphide (Fe@FeP) core-shell nanoparticles on carbon nanotubes (CNTs) where we find that the electronic interactions between the metal and the phosphide components increase the binding strength of hydrogen adatoms toward the optimum. As a consequence, the Fe@FeP/CNT material exhibits exceptional catalytic activity for the hydrogen evolution reaction, only requiring overpotentials of 53-110 mV to reach catalytic current densities of 10-100 mA cm-2.

Self-Cleaning Catalyst Electrodes for Stabilized CO2 Reduction to Hydrocarbons.

A surface-restructuring strategy is presented that involves self-cleaning Cu catalyst electrodes with unprecedented catalytic stability toward CO2 reduction. Under the working conditions, the Pd atoms pre-deposited on Cu surface induce continuous morphological and compositional restructuring of the Cu surface, which constantly refreshes the catalyst surface and thus maintains the catalytic properties for CO2 reduction to hydrocarbons. The Pd-decorated Cu electrode can catalyze CO2 reduction with relatively stable selectivity and current density for up to 16 h, which is one of the best catalytic durability performances among all Cu electrocatalysts for effective CO2 conversion to hydrocarbons. The generality of this approach of utilizing foreign metal atoms to induce surface restructuring toward stabilizing Cu catalyst electrodes against deactivation by carbonaceous species accumulation in CO2 reduction is further demonstrated by replacing Pd with Rh.

Electrochemical CO2 Reduction to Hydrocarbons on a Heterogeneous Molecular Cu Catalyst in Aqueous Solution.

Exploration of heterogeneous molecular catalysts combining the atomic-level tunability of molecular structures and the practical handling advantages of heterogeneous catalysts represents an attractive approach to developing high-performance catalysts for important and challenging chemical reactions such as electrochemical carbon dioxide reduction which holds the promise for converting emissions back to fuels utilizing renewable energy. Thus, far, efficient and selective electroreduction of CO2 to deeply reduced products such as hydrocarbons remains a big challenge. Here, we report a molecular copper-porphyrin complex (copper(II)-5,10,15,20-tetrakis(2,6-dihydroxyphenyl)porphyrin) that can be used as a heterogeneous electrocatalyst with high activity and selectivity for reducing CO2 to hydrocarbons in aqueous media. At -0.976 V vs the reversible hydrogen electrode, the catalyst is able to drive partial current densities of 13.2 and 8.4 mA cm(-2) for methane and ethylene production from CO2 reduction, corresponding to turnover frequencies of 4.3 and 1.8 molecules·site(-1)·s(-1) for methane and ethylene, respectively. This represents the highest catalytic activity to date for hydrocarbon production over a molecular CO2 reduction electrocatalyst. The unprecedented catalytic performance is attributed to the built-in hydroxyl groups in the porphyrin structure and the reactivity of the copper(I) metal center.

Metal/Oxide Interface Nanostructures Generated by Surface Segregation for Electrocatalysis.

Strong metal/oxide interactions have been acknowledged to play prominent roles in chemical catalysis in the gas phase, but remain as an unexplored area in electrocatalysis in the liquid phase. Utilization of metal/oxide interface structures could generate high performance electrocatalysts for clean energy storage and conversion. However, building highly dispersed nanoscale metal/oxide interfaces on conductive scaffolds remains a significant challenge. Here, we report a novel strategy to create metal/oxide interface nanostructures by growing mixed metal oxide nanoparticles on carbon nanotubes (CNTs) and then selectively promoting migration of one of the metal ions to the surface of the oxide nanoparticles and simultaneous reduction to metal. Employing this strategy, we have synthesized Ni/CeO2 nanointerfaces coupled with CNTs. The Ni/CeO2 interface promotes hydrogen evolution catalysis by facilitating water dissociation and modifying the hydrogen binding energy. The Ni/CeO2-CNT hybrid material exhibits superior activity for hydrogen evolution as a result of synergistic effects including strong metal/oxide interactions, inorganic/carbon coupling, and particle size control.

Ferrocene-Promoted Long-Cycle Lithium-Sulfur Batteries.

Confining lithium polysulfide intermediates is one of the most effective ways to alleviate the capacity fade of sulfur-cathode materials in lithium-sulfur (Li-S) batteries. To develop long-cycle Li-S batteries, there is an urgent need for material structures with effective polysulfide binding capability and well-defined surface sites; thereby improving cycling stability and allowing study of molecular-level interactions. This challenge was addressed by introducing an organometallic molecular compound, ferrocene, as a new polysulfide-confining agent. With ferrocene molecules covalently anchored on graphene oxide, sulfur electrode materials with capacity decay as low as 0.014 % per cycle were realized, among the best of cycling stabilities reported to date. With combined spectroscopic studies and theoretical calculations, it was determined that effective polysulfide binding originates from favorable cation-π interactions between Li+ of lithium polysulfides and the negatively charged cyclopentadienyl ligands of ferrocene.

Ternary Hybrid Material for High-Performance Lithium-Sulfur Battery.

The rechargeable lithium-sulfur battery is a promising option for energy storage applications because of its low cost and high energy density. The electrochemical performance of the sulfur cathode, however, is substantially compromised because of fast capacity decay caused by polysulfide dissolution/shuttling and low specific capacity caused by the poor electrical conductivities of the active materials. Herein we demonstrate a novel strategy to address these two problems by designing and synthesizing a carbon nanotube (CNT)/NiFe2O4-S ternary hybrid material structure. In this unique material architecture, each component synergistically serves a specific purpose: The porous CNT network provides fast electron conduction paths and structural stability. The NiFe2O4 nanosheets afford strong binding sites for trapping polysulfide intermediates. The fine S nanoparticles well-distributed on the CNT/NiFe2O4 scaffold facilitate fast Li(+) storage and release for energy delivery. The hybrid material exhibits balanced high performance with respect to specific capacity, rate capability, and cycling stability with outstandingly high Coulombic efficiency. Reversible specific capacities of 1350 and 900 mAh g(-1) are achieved at rates of 0.1 and 1 C respectively, together with an unprecedented cycling stability of ∼0.009% capacity decay per cycle over more than 500 cycles.

Switching Hydrophobic Interface with Ionic Valves for Reversible Zinc Batteries.

Developing hydrophobic interface has proven effective in addressing dendrite growth and side reactions during zinc (Zn) plating in aqueous Zn batteries. However, this solution inadvertently impedes the solvation of Zn2+ with H2O and subsequent ionic transport during Zn stripping, leading to insufficient reversibility. Herein, an adaptive hydrophobic interface that can be switched "on" and "off" by ionic valves to accommodate the varying demands for interfacial H2O during both the Zn plating and stripping processes, is proposed. This concept is validated using octyltrimethyl ammonium bromide (C8TAB) as the ionic valve, which can initiatively establish and remove a hydrophobic interface in response to distinct electric-field directions during Zn plating and stripping, respectively. Consequently, the Zn anode exhibits an extended cycling life of over 2500 h with a high Coulombic efficiency of ≈99.8%. The full cells also show impressive capacity retention of over 85% after 1 000 cycles at 5 A g-1. These findings provide a new insight into interface design for aqueous metal batteries.

Spatial chromatin accessibility sequencing resolves high-order spatial interactions of epigenomic markers.

As the genome is organized into a three-dimensional structure in intracellular space, epigenomic information also has a complex spatial arrangement. However, most epigenetic studies describe locations of methylation marks, chromatin accessibility regions, and histone modifications in the horizontal dimension. Proper spatial epigenomic information has rarely been obtained. In this study, we designed spatial chromatin accessibility sequencing (SCA-seq) to resolve the genome conformation by capturing the epigenetic information in single-molecular resolution while simultaneously resolving the genome conformation. Using SCA-seq, we are able to examine the spatial interaction of chromatin accessibility (e.g. enhancer-promoter contacts), CpG island methylation, and spatial insulating functions of the CCCTC-binding factor. We demonstrate that SCA-seq paves the way to explore the mechanism of epigenetic interactions and extends our knowledge in 3D packaging of DNA in the nucleus.

An investigation of the risk factors of chronic obstructive pulmonary disease in natural population-based cohorts in China - a nested case-control study.

Background: Chronic obstructive pulmonary disease (COPD) has become one of the most significant chronic diseases in China. According to conventional wisdom, smoking is the pathogenic factor. However, current research indicates that the pathophysiology of COPD may be associated with prior respiratory system events (e.g., childhood hospitalization for pneumonia, chronic bronchitis) and environmental exposure (e.g., dust from workplace, indoor combustion particles). Dyspnea, persistent wheezing, and other respiratory symptoms further point to the need for pulmonary function tests in this population. Reducing the burden of chronic diseases in China requires a thorough understanding of the various factors that influence the occurrence of COPD. Methods: Using a cohort from the natural population, this study used nested case-control analysis. We carried out a number of researches, including questionnaire surveys and pulmonary function testing, in the Northwest and Southeast cohorts of China between 2014 and 2021. After removing any variations in the baseline data between patients and control subjects using propensity score matching analysis, the risk factors were examined using univariate or multivariate regression. Result: It was discovered that prior history of chronic bronchitis, long-term wheezing symptoms, and environmental exposure-including smoking and biofuel combustion-were risk factors for COPD. Dyspnea, symptoms of mobility limitation, organic matter, and a history of hospitalization for pneumonia at an early age were not significant in the clinical model but their incidence in COPD group is higher than that in healthy population. Discussion: COPD screening effectiveness can be increased by looking for individuals with chronic respiratory symptoms. Smokers should give up as soon as they can, and families that have been exposed to biofuels for a long time should convert to clean energy or upgrade their ventilation. Individuals who have previously been diagnosed with emphysema and chronic bronchitis ought to be extra mindful of the prevention or advancement of COPD.

A novel red-emitting aggregation-induced emission probe for determination of ß-glucosidase activity.

ß-Glucosidase (ß-Glu) is a ubiquitous enzyme which has multiple roles in medical diagnosis, food production, agriculture, etc. Existing ß-Glu assays have limitations such as complex operation, long running time, and high background noise. Here we report a red-emissive probe TBPG for measuring the activity of ß-Glu. The probe was synthesized through conjugating a ß-Glu targeting glucoside to an aggregation-induced emission (AIE) fluorophore. In the presence of ß-Glu, TBPG was hydrolyzed and exhibited a fluorescence turn-on process. The detection conditions including time, temperature, pH value, buffer, and probe concentration were optimized systematically. Afterwards, fluorescence titration was conducted showing an excellent linearity (R2 = 0.998), a wide linear dynamic range (0-5.0 U/mL), and a limit of detection as low as 0.6 U/L. The detection specificity and ion interference were evaluated by adding various biological species and ions to probe without or with ß-Glu. Next, we demonstrate the applicability of probe TBPG in determining the ß-Glu activity in living cells using confocal microscopy and flow cytometry. Finally, this newly established assay was applied to real soil samples. Comparable results were obtained as the commercial assay, manifesting its great potential in soil enzyme analysis.

Aminosilane Molecular Layer Enables Successive Capture-Diffusion-Deposition of Ions toward Reversible Zinc Electrochemistry.

The aqueous zinc (Zn) battery is a safe and eco-friendly energy-storage system. However, the use of Zn metal anodes is impeded by uncontrolled Zn deposition behavior. Herein, we regulate the Zn-ion deposition process for dendrite-free Zn metal anodes using an aminosilane molecular layer with high zincophilic sites and narrow molecule channels. The aminosilane molecular layer causes Zn ions to undergo consecutive processes including being captured by the amine functional groups of aminosilane and diffusing through narrow intermolecular channels before electroplating, which induces partial dehydration of hydrated Zn ions and uniform Zn ion flux, promoting reversible Zn stripping/plating. Through this molecule-induced capture-diffusion-deposition procedure of Zn ions, smooth and compact Zn electrodeposited layers are obtained. Hence, the aminosilane-modified Zn anode has high Coulombic efficiency (∼99.5%), long lifespan (∼3000 h), and high capacity retention in full cells (88.4% for 600 cycles). This strategy not only has great potential for achieving dendrite-free Zn anodes in practical Zn batteries but also suggests an interface-modification principle at the molecular level for other alternative metallic anodes.