A Hybrid Redox-Mediated Zinc-Air Fuel Cell for Scalable and Sustained Power Generation.

Zinc-air batteries (ZABs) have attracted considerable attention for their high energy density, safety, low noise, and eco-friendliness. However, the capacity of mechanically rechargeable ZABs was limited by the cumbersome procedure for replacing the zinc anode, while electrically rechargeable ZABs suffer from issues including low depth of discharge, zinc dendrite and dead zinc formation, and sluggish oxygen evolution reaction, etc. To address these issues, we report a hybrid redox-mediated zinc-air fuel cell (HRM-ZAFC) utilizing 7,8-dihydroxyphenazine-2-sulfonic acid (DHPS) as the anolyte redox mediator, which shifts the zinc oxidation reaction from the electrode surface to a separate fuel tank. This approach decouples fuel feeding and electricity generation, providing greater operation flexibility and scalability for large-scale power generation applications. The DHPS-mediated ZAFC exhibited a superior peak power density of 0.51 W/cm2 and a continuous discharge capacity of 48.82 Ah with ZnO as the discharge product in the tank, highlighting its potential for power generation.

Optimizing lung biopsy procedures:Comparative analysis of diagnostic efficacy and safety in experimental low-dose, conventional low-dose, and standard-dose CT-guided approaches.

PURPOSE: Lung cancer is a major cause of cancer-related deaths, emphasizing the importance of early diagnosis. CT-guided percutaneous lung biopsy(CT-PLB) is a valuable method for diagnosing lung lesions, but multiple scans can elevate radiation exposure. This study aims to compare diagnostic efficacy and safety across different CT-PLB protocols. METHODS: 273 consecutive patients who underwent CT-PLB between June 2018 and February 2021 were enrolled, and were divided into standard-dose, conventional low-dose, and experimental low-dose groups. The study mainly evaluated technical success, diagnostic efficacy, radiation dose, complications, and image quality. RESULTS: 93 patients were assigned to standard-dose group, 85 to conventional low-dose group, and 95 to experimental low-dose group. Technical success rates in these groups were 97.9%, 100%, and 97.9%, respectively. Procedure-related complications rates were similar across the groups(pneumothorax:p=0.71, hemorrhage:p=0.59). Sensitivity, specificity, and overall diagnostic accuracy were comparable among three groups(p=0.59,1.0,0.65), with respective values of 90.5%, 100%, and 93.2% in standard-dose group, 88.1%, 100%, and 90.5% in conventional low-dose group, and 91.9%, 100%, and 93.4% in experimental low-dose group. The effective dose (ED) in the experimental low-dose group was significantly lower compared to both the standard-dose and conventional low-dose CT-PLB groups[ED: 1.49(1.0∼1.97) mSv vs 5.42(3.92∼6.91) mSv vs 3.15(2.52∼4.22) mSv, p<0.001]. CONCLUSIONS: This study has developed a standardized six-step procedure for CT-PLB using experimental low-dose settings. It can achieve comparable diagnostic efficacy to conventional low-dose and standard-dose CT-PLB protocols while substantially reducing radiation exposure. These findings indicate that the experimental low-dose protocol could serve as a safe and effective alternative for CT-PLB.

Molecular engineering of dihydroxyanthraquinone-based electrolytes for high-capacity aqueous organic redox flow batteries.

Aqueous organic redox flow batteries (AORFBs) are a promising technology for large-scale electricity energy storage to realize efficient utilization of intermittent renewable energy. In particular, organic molecules are a class of metal-free compounds that consist of earth-abundant elements with good synthetic tunability, electrochemical reversibility and reaction rates. However, the short cycle lifetime and low capacity of AORFBs act as stumbling blocks for their practical deployment. To circumvent these issues, here, we report molecular engineered dihydroxyanthraquinone (DHAQ)-based alkaline electrolytes. Via computational studies and operando measurements, we initially demonstrate the presence of a hydrogen bond-mediated degradation mechanism of DHAQ molecules during electrochemical reactions. Afterwards, we apply a molecular engineering strategy based on redox-active polymers to develop capacity-boosting composite electrolytes. Indeed, by coupling a 1,5-DHAQ/poly(anthraquinonyl sulfide)/carbon black anolyte and a [Fe(CN)6]3-/4- alkaline catholyte, we report an AORFB capable of delivering a stable cell discharge capacity of about 573 mAh at 20 mA/cm2 after 1100 h of cycling and an average cell discharge voltage of about 0.89 V at the same current density.

Efficient Low-Grade Heat Conversion and Storage with an Activity-Regulated Redox Flow Cell via a Thermally Regenerative Electrochemical Cycle.

Efficient and cost-effective technologies are highly desired to convert the tremendous amount of low-grade waste heat to electricity. Although the thermally regenerative electrochemical cycle (TREC) has attracted increasing attention recently, the unsatisfactory thermal-to-electrical conversion efficiency and low power density limit its practical applications. In this work, a thermosensitive Nernstian-potential-driven strategy in the TREC system is demonstrated to boost its temperature coefficient, power density, and thermoelectric conversion efficiency by rationally regulating the activities of redox couples at different temperatures. With a Zn anode and [Fe(CN)6 ]4-/3- -guanidinium as the catholyte, the TREC flow cell presents an unprecedented average temperature coefficient of -3.28 mV K-1 , and achieves an absolute thermoelectric efficiency of 25.1% and apparent thermoelectric efficiency of 14.9% relative to the Carnot efficiency in the temperature range of 25-50 °C at 1 mA cm-2 . In addition, a thermoelectric power density of 1.98 mW m-2 K-2 is demonstrated, which is more than 7 times the highest power density of reported TREC systems. This activity regulation strategy can inspire research into high-efficiency and high-power TREC devices for practical low-grade heat harnessing.

Redox Targeting of Energy Materials for Energy Storage and Conversion.

The redox-targeting (RT) process or redox-mediated process, which provides great operation flexibility in circumventing the constraints intrinsically posed by the conventional electrochemical systems, is intriguing for various energy storage and conversion applications. Implementation of the RT reactions in redox-flow cells, which involves a close-loop electrochemical-chemical cycle between an electrolyte-borne redox mediator and an energy storage or conversion material, not only boosts the energy density of flow battery system, but also offers a versatile research platform applied to a wide variety of chemistries for different applications. Here, the recent progress of RT-based energy storage and conversion systems is summarized and great versatility of RT processes for various energy-related applications is demonstrated, particularly for large-scale energy storage, spatially decoupled water electrolysis, electrolytic N2 reduction, thermal-to-electrical conversion, spent battery material recycling, and more. The working principle, materials aspects, and factors dictating the operation are highlighted to reveal the critical roles of RT reactions for each application. In addition, the challenges lying ahead for deployment are stated and recommendations for addressing these constraints are provided. It is anticipated that the RT concept of energy materials will provide important implications and eventually offer a credible solution for advanced large-scale energy storage and conversion.

Experimental and Numerical Studies on the Direct Shear Behavior of Sand-RCA (Recycled Concrete Aggregates) Mixtures with Different Contents of RCA.

Recycled concrete aggregate (RCA) is a typical construction and demolition (C&D) material generated in civil engineering activities and has been widely used as the coarse-grained filler added to sand for roadbed fillings. The effect of RCA content on the mechanical behavior of sand-RCA mixtures is complicated and still not fully understood. To explore the effect of RCA content on the macroscale and microscopic behavior of the sand-RCA mixtures with various RCA contents, laboratory direct shear tests and numerical simulations using the 3D discrete element method were performed. Experimental direct shear tests on sand-RCA mixtures with different contents of RCA were first carried out. Numerical direct shear models were then established to represent the experimental results. The particle shape effect was also considered using a new realistic shape modeling method to model the RCA particles. Good agreement was observed between the DEM simulation and experimental results, verifying the ability of the numerical direct shear models to represent the direct shear behavior of sand-RCA mixtures. The macroscopic responses of both experimental and numerical tests showed that all samples presented an initial hardening followed by a post-peak strain softening. The peak-state friction angles increased with the RCA content for samples under the same vertical stress. The effect of RCA content on the microscopic behavior based on DEM simulation was also found. The microscopic properties of RCA-sand mixtures, such as coordination numbers, PDFs and contact force transformation features, were analyzed and related to the macroscopic results.

Redox-Mediated Ambient Electrolytic Nitrogen Reduction for Hydrazine and Ammonia Generation.

This work presents a redox-mediated electrolytic nitrogen reduction reaction (RM-eNRR) using polyoxometalate (POM) as the electron and proton carrier which frees the TiO2 -based catalyst from the electrode and shifts the reduction of nitrogen to a reactor tank. The RM-eNRR process has achieved an ammonium production yield of 25.1 µg h-1 or 5.0 µg h-1 cm-2 at an ammonium concentration of 6.7 ppm. With high catalyst loading, 61.0 ppm ammonium was accumulated in the electrolyte upon continuous operation, which is the highest concentration detected for ambient eNRR so far. The mechanism underlying the RM-eNRR was scrutinized both experimentally and computationally to delineate the POM-mediated charge transfer and hydrogenation process of nitrogen molecule on the catalyst. RM-eNRR is expected to provide an implementable solution to overcome the limitations in the conventional eNRR process.

Decoupled Redox Catalytic Hydrogen Production with a Robust Electrolyte-Borne Electron and Proton Carrier.

Electrolytic water splitting is an effective approach for H2 mass production. A conventional water electrolyzer concurrently generates H2 and O2 in neighboring electrode compartments separated by a membrane, which brings about compromised purity, energy efficiency, and system durability. On the basis of distinct redox electrochemistry, here, we report a system that enables the decoupling of both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) from the electrodes to two spatially separated catalyst bed reactors in alkaline solutions. Through a pair of close-loop electrochemical-chemical cycles, the system operates upon 7,8-dihydroxy-2-phenazinesulfonic acid (DHPS) and ferricyanide-mediated HER and OER, respectively, on Pt/Ni(OH)2 and NiFe(OH)2 catalysts. Near unity faradaic efficiency and sustained production of hydrogen has been demonstrated at a current density up to 100 mA/cm2. The superior reaction kinetics, particularly the HER reaction mechanism of DHPS as a robust electrolyte-borne electron and proton carriers, were scrutinized both computationally and experimentally. We anticipate the system demonstrated here would provide an intriguing alternative to the conventional water electrolytic hydrogen production.

Nanostructured Phosphorus Doped Silicon/Graphite Composite as Anode for High-Performance Lithium-Ion Batteries.

Silicon as the potential anode material for lithium-ion batteries suffers from huge volume change (up to 400%) during charging/discharging processes. Poor electrical conductivity of silicon also hinders its long-term cycling performance. Herein, we report a two-step ball milling method to prepare nanostructured P-doped Si/graphite composite. Both P-doped Si and coated graphite improved the conductivity by providing significant transport channels for lithium ions and electrons. The graphite skin is able to depress the volume expansion of Si by forming a stable SEI film. The as-prepared composite anode having 50% P-doped Si and 50% graphite exhibits outstanding cyclability with a specific capacity of 883.4 mAh/g after 200 cycles at the current density of 200 mA/g. The cost-effective materials and scalable preparation method make it feasible for large-scale application of the P-doped Si/graphite composite as anode for Li-ion batteries.

A novel solid-phase microextraction method based on polymer monolith frit combining with high-performance liquid chromatography for determination of aldehydes in biological samples.

In this work, a polypropylene frit with porous network structure (20 µm pole size) was first utilized as the mould of polymer monolithic material, poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-co-EDMA) monolith was synthesized within channels and macropores of the frit. A simple and sensitive solid-phase microextraction method based on polymer monolith frit coupled with high-performance liquid chromatography (HPLC) was established and applied to analysis of hexanal and heptanal in biological samples (human urine and serum). In the method, small molecule metabolites (aldehydes) in biological samples derivatized with 2,4-dinitrophenylhydrazine (DNPH), and the formed hydrazones were extracted simultaneously on the monolithic frit and thereafter ultrasound-assisted desorbed with acetonitrile as elution solvent. The experimental parameters with regard to polymerization, derivatization and extraction were investigated. Under the optimal conditions, the linearity was in the range of 0.02-5.0 µmol L(-1) (r=0.9994) for both hexanal and heptanal and the limits of detection (S/N=3) were 0.81 nmol L(-1) for hexanal and 0.76 nmol L(-1) for heptanal. The relative standard deviations (RSDs, n=5) were less than 6.5% for the same monolithic frit and less than 8.9% for the different monolithic frits. Satisfactory recoveries ranging from 70.71% to 88.73% were obtained for the urine samples. The method possesses many advantages including simple setup, fast analysis, low cost, sufficient sensitivity, good biological compatibility and less organic solvent consumption. The proposed method is a useful assistant tool in the clinical early diagnosis of lung disease by monitoring aldehyde biomarker candidates in complex biological samples.

Phylogeography and genetic ancestry of tigers (Panthera tigris).

Eight traditional subspecies of tiger (Panthera tigris),of which three recently became extinct, are commonly recognized on the basis of geographic isolation and morphological characteristics. To investigate the species' evolutionary history and to establish objective methods for subspecies recognition, voucher specimens of blood, skin, hair, and/or skin biopsies from 134 tigers with verified geographic origins or heritage across the whole distribution range were examined for three molecular markers: (1) 4.0 kb of mitochondrial DNA (mtDNA) sequence; (2) allele variation in the nuclear major histocompatibility complex class II DRB gene; and (3) composite nuclear microsatellite genotypes based on 30 loci. Relatively low genetic variation with mtDNA,DRB,and microsatellite loci was found, but significant population subdivision was nonetheless apparent among five living subspecies. In addition, a distinct partition of the Indochinese subspecies P. t. corbetti in to northern Indochinese and Malayan Peninsula populations was discovered. Population genetic structure would suggest recognition of six taxonomic units or subspecies: (1) Amur tiger P. t. altaica; (2) northern Indochinese tiger P. t. corbetti; (3) South China tiger P. t. amoyensis; (4) Malayan tiger P. t. jacksoni, named for the tiger conservationist Peter Jackson; (5) Sumatran tiger P. t. sumatrae; and (6) Bengal tiger P. t. tigris. The proposed South China tiger lineage is tentative due to limited sampling. The age of the most recent common ancestor for tiger mtDNA was estimated to be 72,000-108,000 y, relatively younger than some other Panthera species. A combination of population expansions, reduced gene flow, and genetic drift following the last genetic diminution, and the recent anthropogenic range contraction, have led to the distinct genetic partitions. These results provide an explicit basis for subspecies recognition and will lead to the improved management and conservation of these recently isolated but distinct geographic populations of tigers.