Silica Polymerization Driving Opposite Effects of pH on Aqueous Carbonation Using Crystalline and Amorphous Calcium Silicates.

The aqueous carbonation of calcium silicate (CS), a representative alkaline-earth silicate, has been widely explored in studies of carbon dioxide (CO2) mineralization. In this context, we conducted a specific comparison of the carbonation behaviors between the crystalline calcium silicate (CCS) and amorphous calcium silicate (ACS) across a pH range from 9.0 to 12.0. Interestingly, we observed opposite pH dependencies in the carbonation efficiencies (i.e., CaO conversion into CaCO3 in 1 M Na2CO3/NaHCO3 solution under ambient conditions) of CCS and ACS─the carbonation efficiency of CCS decreased with increasing the solution basicity, while that of ACS showed an inverse trend. In-depth insights were gained through in situ Raman characterizations, indicating that these differing trends appeared to originate from the polymerization/depolymerization behaviors of silicates released from minerals. More specifically, higher pH conditions seemed to favor the carbonation of minerals containing polymerized silica networks. These findings may contribute to a better understanding of the fundamental factors influencing the carbonation behaviors of alkaline earth silicates through interfacial coupled dissolution and precipitation processes. Moreover, they offer valuable insights for selecting optimal carbonation conditions for alkaline-earth silicate minerals.

Visualization-enhanced under-oil open microfluidic system for in situ characterization of multi-phase chemical reactions.

Under-oil open microfluidic system, utilizing liquid-liquid boundaries for confinements, offers inherent advantages including clogging-free flow channels, flexible access to samples, and adjustable gas permeation, making it well-suited for studying multi-phase chemical reactions that are challenging for closed microfluidics. However, reports on the novel system have primarily focused on device fabrication and functionality demonstrations within biology, leaving their application in broader chemical analysis underexplored. Here, we present a visualization-enhanced under-oil open microfluidic system for in situ characterization of multi-phase chemical reactions with Raman spectroscopy. The enhanced system utilizes a semi-transparent silicon (Si) nanolayer over the substrate to enhance visualization in both inverted and upright microscope setups while reducing Raman noise from the substrate. We validated the system's chemical stability and capability to monitor gas evolution and gas-liquid reactions in situ. The enhanced under-oil open microfluidic system, integrating Raman spectroscopy, offers a robust open-microfluidic platform for label-free molecular sensing and real-time chemical/biochemical process monitoring in multi-phase systems.

Designing Human-Centered AI to Prevent Medication Dispensing Errors: Focus Group Study With Pharmacists.

BACKGROUND: Medication errors, including dispensing errors, represent a substantial worldwide health risk with significant implications in terms of morbidity, mortality, and financial costs. Although pharmacists use methods like barcode scanning and double-checking for dispensing verification, these measures exhibit limitations. The application of artificial intelligence (AI) in pharmacy verification emerges as a potential solution, offering precision, rapid data analysis, and the ability to recognize medications through computer vision. For AI to be embraced, it must be designed with the end user in mind, fostering trust, clear communication, and seamless collaboration between AI and pharmacists. OBJECTIVE: This study aimed to gather pharmacists' feedback in a focus group setting to help inform the initial design of the user interface and iterative designs of the AI prototype. METHODS: A multidisciplinary research team engaged pharmacists in a 3-stage process to develop a human-centered AI system for medication dispensing verification. To design the AI model, we used a Bayesian neural network that predicts the dispensed pills' National Drug Code (NDC). Discussion scripts regarding how to design the system and feedback in focus groups were collected through audio recordings and professionally transcribed, followed by a content analysis guided by the Systems Engineering Initiative for Patient Safety and Human-Machine Teaming theoretical frameworks. RESULTS: A total of 8 pharmacists participated in 3 rounds of focus groups to identify current challenges in medication dispensing verification, brainstorm solutions, and provide feedback on our AI prototype. Participants considered several teaming scenarios, generally favoring a hybrid teaming model where the AI assists in the verification process and a pharmacist intervenes based on medication risk level and the AI's confidence level. Pharmacists highlighted the need for improving the interpretability of AI systems, such as adding stepwise checkmarks, probability scores, and details about drugs the AI model frequently confuses with the target drug. Pharmacists emphasized the need for simplicity and accessibility. They favored displaying only essential information to prevent overwhelming users with excessive data. Specific design features, such as juxtaposing pill images with their packaging for quick comparisons, were requested. Pharmacists preferred accept, reject, or unsure options. The final prototype interface included (1) checkmarks to compare pill characteristics between the AI-predicted NDC and the prescription's expected NDC, (2) a histogram showing predicted probabilities for the AI-identified NDC, (3) an image of an AI-provided "confused" pill, and (4) an NDC match status (ie, match, unmatched, or unsure). CONCLUSIONS: In partnership with pharmacists, we developed a human-centered AI prototype designed to enhance AI interpretability and foster trust. This initiative emphasized human-machine collaboration and positioned AI as an augmentative tool rather than a replacement. This study highlights the process of designing a human-centered AI for dispensing verification, emphasizing its interpretability, confidence visualization, and collaborative human-machine teaming styles.

Prevalence of wound infections and postoperative complications after total elbow arthroplasty for rheumatoid arthritis: A meta-analysis.

This study aimed to systematically evaluate the prevalence of surgical site wound infections and postoperative complications after total elbow arthroplasty (TEA) in patients with rheumatoid arthritis (RA) for clinical research and application. Embase, PubMed, Cochrane Library, CNKI, VIP, CBM, and Wanfang databases were electronically searched to collect clinical studies on the application of TEA in the treatment of RA from inception to August 2023. Two independent researchers performed literature screening, data extraction, and quality assessment. A meta-analysis was performed using the R 4.3.1 software. Overall, 26 studies with a total of 2374 patients were included. The results of the meta-analysis revealed that after TEA in patients with RA, the prevalence of surgical site wound infections and postoperative complications was 3.37% (95% confidence interval [CI]: 2.68%-4.13%), and 31.63% (95% CI: 24.97%-38.28%), respectively. The prevalence of surgical site wound infections is low, whereas that of postoperative complications is high; thus, the safety of TEA remains debatable. Owing to limitations on the quality and number of included studies, the findings need to be verified in higher-quality studies.

Enhancing Aqueous Carbonation of Calcium Silicate through Acid and Base Pretreatments with Implications for Efficient Carbon Mineralization.

Carbon dioxide (CO2) mineralization based on aqueous carbonation of alkaline earth silicate minerals is a promising route toward large-scale carbon removal. Traditional aqueous carbonation methods largely adopt acidification-based approaches, e.g., using concentrated/pressurized CO2 or acidic media, to accelerate mineral dissolution and carbonation. In this study, we designed and tested three distinctive routes to evaluate the effect of pretreatments under different pH conditions on aqueous carbonation, using amorphous calcium silicate (CS) as an example system. Pretreating CS with high concentrations (100 mM) of HCl (Route I) or NaOH (Route II and III) enhanced their carbonation degrees. However, NaOH pretreatment overall yielded higher carbonation degrees than the HCl pretreatment, with the highest carbonation degree achieved through Route III, where an extra step is taken after the NaOH pretreatment to remove the solution containing dissolved silica prior to carbonation. The HCl and NaOH pretreatments formed different intermediate silica products on the CS surface. Silica precipitated from the HCl pretreatment had a minimal effect on the carbonation degree. The high Ca/Si ratio intermediate phases formed from the NaOH, on the other hand, can be readily carbonated. In contrast to commonly utilized acidification-based approaches, basification offers a more promising route to accelerate aqueous carbonation as it can mitigate the need for costly pH swing and high-concentration/pressurized CO2. The key to aqueous carbonation under basic conditions, as suggested by this study, is the control of aqueous silica species that have a suppressing effect on carbonation. Overall, this study highlights the critical needs for investigations of aqueous mineral carbonation in a broader pH region.

Synthesis of dual-modified Fe-doped and carbon-coated Li4Ti5O12 anode based on industrial H2TiO3 for Li-ion batteries.

Spinel Li4Ti5O12 (LTO) is a promising candidate for lithium-ion battery anodes because of its exceptional stability and safety. However, its extensive application is limited by a high comprehensive cost, poor electronic conductivity, and other inherent defects. This work presents a novel synthesis procedure to synthesize carbon-coated Fe-doped LTO composites through carbon reduction, in the presence of Fe-containing industrial H2TiO3 as the titanium source, and glucose as the carbon source. The presence of the Fe-dopant is confirmed through XRD, with Rietveld refinement and EDS experiments. Results show that Fe2+ replaces a portion of Ti4+ after doping, leading to an increase in the LTO cell parameters and the corresponding cell volume. FLTO/C, presents a capacity of 153.79 mAh g-1 at 10 C, and the capacity decay per cycle is only 0.0074% after 1000 cycles at 5 C. Moreover, EIS experiments indicate that the incorporation of Fe and carbon lowers the charge transfer resistance and improves the diffusion and migration of Li+. Notably, since this preparation process requires no additional Fe source as a raw material, it is simple, cost-effective, and suitable for large-scale production and further application.

Rapid Response in an Uncertain Environment: Study of COVID-19 Scientific Research Under the Parallel Model.

PURPOSE: The rapid response of COVID-19 scientific research played a significant role in pandemic prevention and control but failed to block the spread of the pandemic rapidly. Besides the complexity of the virus, the effectiveness of control and prevention measures, and other factors, the adaptation of the mode of conducting scientific research is also crucial for the prevention and control of COVID-19. In this study, a parallel model was used to explore the effects of the rapid scientific response on COVID-19 to assess why pandemics continue to spread under rapid response. ANALYSIS: This study presents the response of scientific research based on country/region and publication dimensions after analyzing COVID-19 studies in the Web of Science and PubMed databases. Co-occurrence analysis of items was used to determine the generation rate of COVID-19 research under different topics to identify the reflected innovation model. RESULTS: More manifestations on rapid response of COVID-19 research, especially compared with the linear model of SARS research, showed that the COVID-19 research followed a parallel or concurrent innovation model. CONCLUSION: Early multi-stakeholder partnership, convenient information sharing, and improved research competence promote the parallel model in COVID-19. Meanwhile, the uncertainty of the COVID-19 virus and the adverse effect of rapid response may limit the time efficiency of the parallel model. In conclusion, the rapid prevention and control of the pandemic cannot fully rely on scientific research but requires more combined effort under an uncertain global setting.

A Novel Nomogram for Predicting Morbidity Risk in Patients with Secondary Malignant Neoplasm of Bone and Bone Marrow: An Analysis Based on the Large MIMIC-III Clinical Database.

Objective: Bone and bone marrow are the third most frequent sites of metastases from many cancers and are associated with low survival and high morbidity rates. Currently, there are no effective bedside tools to predict the morbidity risk of these patients in general intensive care units (ICUs). The main objective of this study was to establish and validate a nomogram to predict the morbidity risk of patients with bone and bone marrow metastases. Methods: Data on patients with bone and bone marrow metastases were extracted from the Medical Information Mart for Intensive Care III (MIMIC-III) database. The patients were divided into training and validation cohorts. The data were analyzed using univariate and multivariate Cox regression methods. Factors significantly and independently prognostic of survival were used to construct a nomogram predicting 30-day morbidity. The nomogram was validated by various methods, including Harrell's concordance index (C-index), area under the receiver operating characteristic curve (AUC), calibration curve, integrated discrimination improvement (IDI), net reclassification index (NRI), and decision curve analysis (DCA). Results: The study included 610 patients in the training cohort and 262 in the validation cohort. Multivariate Cox regression analysis showed that temperature, SpO2, Sequential Organ Failure Assessment (SOFA) score, Oxford Acute Severity of Illness Score (OASIS), comorbidities with coagulopathy, white blood cell count, heart rate, and respiratory rate were independent predictors of patient survival. The resulting nomogram had good discriminative ability, as shown by high AUCs, and was well calibrated, as demonstrated by calibration curves. Improvements in NRI and IDI values suggested that the nomogram was superior to the SOFA scoring system. DCA curves revealed that the nomogram showed good value in clinical applications. Conclusion: This prognostic nomogram, based on demographic and laboratory parameters, was predictive of the 30-day morbidity rate in patients with secondary malignant neoplasms of the bone and bone marrow, suggesting its applicability in clinical practice.

Robust and Multifunctional Porous Polyetheretherketone Fiber Fabricated via a Microextrusion CO2 Foaming.

Fabrication of multifunctional porous fibers with excellent mechanical properties has attracted abundant attention in the fields of personal thermal management textiles and smart wearable devices. However, the high cost and harsh preparation environment of the traditional solution-solvent phase separation method for making porous fibers aggravates the problems of resource consumption and environmental pollution. Herein, a microextrusion process that combines environmentally friendly CO2 physical foaming with fused deposition modeling technology is proposed, via the dual features of high gas uptake and restricted cell growth, to implement the continuous production of porous polyetheretherketone (PEEK) fibers with a production efficiency of 10.5 cm s-1 . The porous PEEK fiber exhibits excellent stretchability (234.8% strain) and good high-temperature thermal insulation property. The open-cell structure on the surface is favorable for the adsorption to achieve superhydrophobicity (154.4°) and high-efficiency photocatalytic degradation of rhodamine B (90.4%). Moreover, the parameterized controllability of the cell structure is beneficial to widening the multifunctional window. In short, the first porous PEEK physical foaming fiber, which opens up a new avenue for the application expansion, especially in the medical field, is realized.

[Large- scale prospective clinical study on prophylactic intervention of COVID-19 in community population using Huoxiang Zhengqi Oral Liquid and Jinhao Jiere Granules].

To scientifically evaluate the intervention effect of Chinese medicine preventive administration(combined use of Huo-xiang Zhengqi Oral Liquid and Jinhao Jiere Granules) on community population in the case of coronavirus disease 2019(COVID-19), a large cohort, prospective, randomized, and parallel-controlled clinical study was conducted. Total 22 065 subjects were included and randomly divided into 2 groups. The non-intervention group was given health guidance only, while the traditional Chinese medicine(TCM) intervention group was given two coordinated TCM in addition to health guidance. The medical instructions were as follows. Huoxiang Zhengqi Oral Liquid: oral before meals, 10 mL/time, 2 times/day, a course of 5 days. Jinhao Jiere Granules: dissolve in boiling water and take after meals, 8 g/time, 2 times/day, a course of 5 days, followed up for 14 days, respectively. The study found that with the intake of medication, the incidence rate of TCM intervention group was basically maintained at a low and continuous stable level(0.01%-0.02%), while the non-intervention group showed an overall trend of continuous growth(0.02%-0.18%) from 3 to 14 days. No suspected or confirmed COVID-19 case occurred in either group. There were 2 cases of colds in the TCM intervention group and 26 cases in the non-intervention group. The incidence of colds in the TCM intervention group was significantly lower(P<0.05) than that in the non-intervention group. In the population of 16-60 years old, the incidence rate of non-intervention and intervention groups were 0.01% and 0.25%, respectively. The difference of colds incidence between the two groups was statistically significant(P<0.05). In the population older than 60 years old, they were 0.04% and 0.21%, respectively. The incidence of colds in the non-intervention group was higher than that in the intervention group, but not reaching statistical difference. The protection rate of TCM for the whole population was 91.8%, especially for the population of age 16-60(95.0%). It was suggested that TCM intervention(combined use of Huoxiang Zhengqi Oral Liquid and Jinhao Jiere Granules) could effectively protect community residents against respiratory diseases, such as colds, which was worthy of promotion in the community. In addition, in terms of safety, the incidence of adverse events and adverse reactions in the TCM intervention group was relatively low, which was basically consistent with the drug instructions.

A novel UV-assisted PEC-MFC system with CeO2/TiO2/ACF catalytic cathode for gas phase VOCs treatment.

Emissions of volatile organic compounds (VOCs) air pollutants could worsen air quality and adversely affect human health, thus developing more efficient low-temperature VOCs removal techniques is desired. A novel continuous system integrating UV-assisted photo-electrochemical catalysis with microbial fuel cell (UV-assisted PEC-MFC) has been established for promoting removal of gaseous ethyl acetate or toluene and generating electricity simultaneously. In this system, CeO2/TiO2/ACF catalytic cathode is prepared and used for combination with bio-anode for accelerating cathodic reaction. This UV-assisted PEC-MFC system exhibits an excellent elimination capacity (EC) of ethyl acetate (∼0.39 g/m3, EC: ∼2.52 g/m3/h) or toluene (∼0.29 g/m3, EC: 1.89 g/m3/h) under close-circuit condition. Furthermore, an outstanding elimination capacity (EC: 28.04 g/m3/h) for high concentration toluene (∼4.10 g/m3) removal is obtained after toluene gas passes sequentially through the catalytic cathode then the bio-anode. This way of PEC degradation and biodegradation, avoids inhibition of exoelectrogens activity from toxicity of high concentration toluene. Simultaneously, the cell voltage of UV-assisted PEC-MFC system is stable at 0.11 V (vs. SCE) and 1.452×10-4 kWh is generated from treatment of toluene gas stream in 6 h duration time. The possible mechanism of VOCs removal in this novel system has been proposed and discussed. This study provides new technical basis for treating gaseous pollutants via integrating photo-electrochemical catalysis with electricity generating microbial fuel cell for energy conversion.

A One-Pot Synthesis and Characterization of Antibacterial Silver Nanoparticle-Cellulose Film.

Using N,N-dimethylacetamide (DMAc) as a reducing agent in the presence of PVP-K30, the stable silver nanoparticles (Ag-NPs) solution was prepared by a convenient method for the in situ reduction of silver nitrate. The cellulose-Ag-NPs composite film (CANF) was cast in the same container using lithium chloride (LiCl) giving the Ag-NPs-PVP/DMAc solution cellulose solubility as well as γ-mercaptopropyltrimethoxysilane (MPTS) to couple Ag-NPs and cellulose. The results showed that the Ag-NPs were uniformly dispersed in solution, and the solution had strong antibacterial activities. It was found that the one-pot synthesis allowed the growth of and cross-linking with cellulose processes of Ag-NPs conducted simultaneously. Approximately 61% of Ag-NPs was successfully loaded in CANF, and Ag-NPs were uniformly dispersed in the surface and internal of the composite film. The composite film exhibited good tensile properties (tensile strength could reach up to 86.4 MPa), transparency (light transmittance exceeds 70%), thermal stability, and remarkable antibacterial activities. The sterilization effect of CANF0.04 against Staphylococcus aureus and Escherichia coli exceed 99.9%. Due to low residual LiCl/DMAc and low diffusion of Ag-NPs, the composite film may have potential for applications in food packaging and bacterial barrier.

A Nano-shield Design for Separators to Resist Dendrite Formation in Lithium-Metal Batteries.

Lithium dendrite growth during repeated charge and discharge cycles of lithium-metal anodes often leads to short-circuiting by puncturing the porous separator. Here, a morphological design, the nano-shield, for separators to resist dendrites is presented. Through both mechanical analysis and experiment, it is revealed that the separator protected by the nano-shield can effectively inhibit the penetration of lithium dendrites owing to the reduced stress intensity generated and therefore mitigate the short circuit of Li metal batteries. More than 110 h of lithium plating life is achieved in cell tests, which is among the longest cycle life of lithium metal anode and five times longer than that of blank separators. This new aspect of morphological and mechanical design not only provides an alternative pathway for extending lifetime of lithium metal anodes, but also sheds light on the role of separator engineering for various electrochemical energy storage devices.

Morphology-Controllable Collagen/Poly(2-hydroxyethyl methacrylate) Porous Hydrogel with a Paraffin Microsphere as a Template.

In this study, a porous poly(2-hydroxyethyl methacrylate) (PHEMA) matrix was fabricated by a paraffin template method, which was used as a substrate to adhere collagen fibers to form an interconnective porous collagen/PHEMA (Col-PHEMA) composite hydrogel. A microscope and scanning electron microscope (SEM) were employed to characterize the morphology of paraffin microspheres and Col-PHEMA composite hydrogels. The paraffin microspheres with the diameter in the range from 100 to 200 µm were collected by a preset sieve. Then, the interface of uniform paraffin microspheres were thermally bonded to form a contacted template, and the derived Col-PHEMA composite hydrogels had an interconnective porous microstructure. Fourier transform infrared spectroscopy (FTIR) indicated that new hydrogen bonds were formed between collagen fibers and the PHEMA hydrogel. Besides, the Col-PHEMA composite hydrogels revealed a high hydrophilicity, good mechanical properties, and good water uptake capacity. The porous Col-PHEMA composite hydrogels showed a good biocompatibility, and the collagen layer may promote the proliferation of fibroblast cells. The Col-PHEMA composite hydrogel is expected to find an application in corneal repairing.

Multigene editing via CRISPR/Cas9 guided by a single-sgRNA seed in Arabidopsis.

We report that a solo single-guide RNA (sgRNA) seed is capable of guiding Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR -associated 9 (CRISRP/Cas9) to simultaneously edit multiple genes AtRPL10A, AtRPL10B and AtRPL10C in Arabidopsis. Our results also demonstrate that it is possible to use CRISPR/Cas9 technology to create AtRPL10 triple mutants which otherwise cannot be generated by conventional genetic crossing. Compared to other conventional multiplex CRISPR/Cas systems, a single sgRNA seed has the advantage of reducing off-target gene-editing. Such a gene editing system might be also applicable to modify other homologous genes, or even less-homologous sequences for multiple gene-editing in plants and other organisms.

In situ synthesis of Bi2S3 sensitized WO3 nanoplate arrays with less interfacial defects and enhanced photoelectrochemical performance.

In this study, Bi2S3 sensitive layer has been grown on the surface of WO3 nanoplate arrays via an in situ approach. The characterization of samples were carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and ultraviolet-visible absorption spectroscopy (UV-vis). The results show that the Bi2S3 layer is uniformly formed on the surface of WO3 nanoplates and less interfacial defects were observed in the interface between the Bi2S3 and WO3. More importantly, the Bi2S3/WO3 films as photoanodes for photoelectrochemical (PEC) cells display the enhanced PEC performance compared with the Bi2S3/WO3 films prepared by a sequential ionic layer adsorption reaction (SILAR) method. In order to understand the reason for the enhanced PEC properties, the electron transport properties of the photoelectrodes were studied by using the transient photocurrent spectroscopy and intensity modulated photocurrent spectroscopy (IMPS). The Bi2S3/WO3 films prepared via an in situ approach have a greater transient time constant and higher electron transit rate. This is most likely due to less interfacial defects for the Bi2S3/WO3 films prepared via an in situ approach, resulting in a lower resistance and faster carrier transport in the interface between WO3 and Bi2S3.

Highly Efficient Photoelectrochemical Hydrogen Generation Using Zn(x)Bi2S(3+x) Sensitized Platelike WO3 Photoelectrodes.

Zn(x)Bi2S(3+x) sensitized platelike WO3 photoelectrodes on FTO substrates were for the first time prepared via a sequential ionic layer adsorption reaction (SILAR) process. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet visible spectrometry (UV-vis), and Raman spectra. The results show that the ZnxBi2S3+x quantum dots (QDs) are uniformly coated on the entire surface of WO3 plates, forming a WO3/Zn(x)Bi2S(3+x) core/shell structure. The Zn(x)Bi2S(3+x)/WO3 films show a superior ability to capture visible light. High-efficiency photoelectrochemical (PEC) hydrogen generation is demonstrated using the prepared electrodes as photoanodes in a typical three-electrode electrochemical cell. Compared to the Bi2S3/WO3 photoelectrodes, the Zn(x)Bi2S(3+x)/WO3 photoelectrodes exhibit good photostability and excellent PEC activity, and the photocurrent density is up to 7.0 mA cm(-2) at -0.1 V versus Ag/AgCl under visible light illumination. Investigation of the electron transport properties of the photoelectrodes shows that the introduction of ZnS enhances the photoelectrons' transport rate in the photoelectrode. The high PEC activity demonstrates the potential of the Zn(x)Bi2S(3+x)/WO3 film as an efficient photoelectrode for hydrogen generation.

A promising Na3V2(PO4)3 cathode for use in the construction of high energy batteries.

High-energy batteries need significant cathodes which can simultaneously provide large specific capacities and high discharge plateaus. NASICON-structured Na3V2(PO4)3 (NVP) has been utilised as a promising cathode to meet this requirement and be used in the construction of high energy batteries. For a hybrid-ion battery by employing metallic lithium as an anode, NVP exhibits an initial specific capacity of 170 mA h g(-1) in the voltage range of 1.6-4.8 V with a long discharge plateau around 3.7 V. Three Na(2) sites for NVP are found capable to be utilised through the application of a wide voltage window but only two of them are able to undergo ions exchange to produce a NaLi2V2(PO4)3 phase. However, a hybrid-ion migration mechanism is suggested to exist to describe the whole ion transport in which the effects of a Na-ion "barrier" results in a lowered ion diffusion rate and observed specific capacity.

Microscopic insights into extraction mechanism of copper(II) in ammoniacal solutions studied by X-ray absorption spectroscopy and density functional theory calculation.

A microscopic investigation on the extraction process of copper(II) in ammoniacal solutions has been performed by X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculation. The structural change of copper(II) species in ammoniacal solution has been derived from X-ray absorption near-edge spectroscopy (XANES) by principal component analysis and linear combination fitting. It was found that the coordination structure of the extracted copper complex in the organic phases is planar square and independent of the aqueous pH, whereas the geometries of copper(II) species in ammoniacal solutions changed from axially elongated octahedron to distorted planar square with increase of pH. The coordination geometry and structural parameters of copper(II) species were further obtained by extended X-ray absorption fine structure (EXAFS) fitting and DFT calculation with the B3LYP functional. These results reveal that the formation of tetracoordinated copper(II) ammine species can evidently inhibit the copper extraction reaction. Thus, the extraction mechanism of copper(II) in ammoniacal solutions has been elucidated in view of the microscopic structural aspects of copper species in both organic phase and ammoniacal solutions.