Prominent Ions Research Articles

Anion Selectivities in Zwitterion Grafted Nanopores: Effect of Zwitterion Architecture.

The separation of ions of similar charge is a crucial challenge in many applications, from water treatment to precious metal recovery. Membranes with cross-linked zwitterionic amphiphilic copolymer (ZAC-X) selective layers, which feature self-assembled, zwitterion-lined nanodomains for permeation, offer unique permselectivity between monovalent anions (e.g., Cl-/F-). This has motivated studies on the mechanisms of transport and selectivity in this family of materials. In this study, we conducted molecular dynamics simulations of aqueous salt solutions within zwitterion-functionalized nanopores to elucidate the influence of dipole orientation of the ZI ligands on anion diffusivities, partitioning, and permeabilities. Our model compares systems with contrasting ZI organization: surface-cation-anion (S-ZI+-ZI-, Motif A) and surface-anion-cation (S-ZI--ZI+, Motif B). Our results reveal that Motif A exhibits less pronounced ion pairing due to a spatial separation in the radial profiles of cations and anions. Motif B demonstrates prominent ion pairing for smaller anions owing to their overlap with cation distributions. Further, our potential of mean force profiles reveals that anion partitioning increases with anion size in both ligand motifs, whereas Motif B exhibits significantly higher partitioning selectivity toward larger anions compared to Motif A. Our results for ion diffusivities show that the self-diffusivities of both anions and cations are lower for Motif B compared to Motif A. Such trends in anion partitioning and diffusivities can be explained by differences in the interactions and steric hindrance experienced by the anionic species in Motifs A and B. Finally, our results for anion permselectivity, obtained by combining partitioning and diffusivity, indicate that partitioning trends dominate over diffusivity trends. Consequently, anion permeability increases with anion size, and ligand Motif B yields much higher permselectivity toward larger anions compared to ligand Motif A.

Demystifying ionic and electronic transport in prominent oxide ion and proton conducting ceramic electrolytes: Ce0.8Sm0.2O2 and BaCe0.7Zr0.1Y0.1Yb0.1O3-δ

ABSTRACT The development and performance of ceramic electrochemical cells (CECs) depend critically on choosing ceramic electrolytes with optimal ionic and electronic transport properties. In this study, we compare the structural, morphological, and transport characteristics of two representative ceramic electrolytes, oxide ion conducting Ce0.8Sm0.2O2 (SDC) and proton conducting BaCe0.7Zr0.1Y0.1Yb0.1O3-δ (BCZYYb). We demonstrate that SDC exhibits higher bulk conductivity but lower open-circuit voltage due to its higher electron density and larger crystallite size. In contrast, BCZYYb possesses higher proton conduction, lower activation energy (0.35–0.38 eV), and higher open-circuit voltage due to its lower electron density and smaller crystallite size with more grain boundaries. BCZYYb shows enhanced proton conductivity in humidified atmospheres due to the hydration of oxygen vacancies, making it more suitable for low-temperature CEC applications. These insights into ceramic electrolyte conduction mechanisms and microstructure-property relationships can guide the optimization of CECs for energy applications.

Enhancing the sequence coverage of nanodiamond-extracted early secretory proteins from the Mycobacterium tuberculosis complex.

The unambiguous identification of protein species requires high sequence coverage. In this study, we successfully improved the sequence coverage of early secretory 10 kDa cell filtrate protein (CFP-10) and 6 kDa early secretory antigenic target (ESAT-6) proteins from the Mycobacterium tuberculosis complex (MTC) in broth culture media with the use of the 4-chloro-α-cyanocinnamic acid (Cl-CCA) matrix. Conventional matrices, α-cyano-hydroxy-cinnamic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB), were also used for comparison. After nanodiamond (ND) extraction, the sequence coverage of the CFP-10 protein was 87% when CHCA and DHB matrices were used, and the ESAT-6 protein was not detected. On the other hand, the sequence coverage for ND-extracted CFP-10 and ESAT-6 could reach 94% and 100%, respectively, when the Cl-CCA matrix was used and with the removal of interference from bovine serum albumin (BSA) protein and α-crystallin (ACR) protein. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) was also adopted to analyze the protein mass spectra. A total of 6 prominent ion signals were observed, including ESAT-6 protein peaks at mass-to-charge ratios (m/z) of ∼7931, ∼7974, ∼9768, and ∼9813 and CFP-10 protein peaks at m/z of ∼10 100 and ∼10 660. The ESAT-6 ion signals were always detected concurrently with CFP-10 ion signals, but CFP-10 ion signals could be detected alone without the ESAT-6 ion signals. Furthermore, the newly found ESAT-6 peaks were also confirmed using a Mag-Beads-Protein G kit with an ESAT-6 antibody to capture the ESAT-6 protein, which was also consistent with the sequence coverage analysis.

Covalently Functionalized Nanopores for Highly Selective Separation of Monovalent Ions.

Biological ion channels possess prominent ion transport performances attributed to their critical chemical groups across the continuous nanoscale filters. However, it is still a challenge to imitate these sophisticated performances in artificial nanoscale systems. Herein, this work develops the strategy to fabricate functionalized graphene nanopores in pioneer based on the synergistic regulation of the pore size and chemical properties of atomically thin confined structure through decoupling etching combined with in situ covalent modification. The modified graphene nanopores possess asymmetric ion transport behaviors and efficient monovalent metal ions sieving (K+ /Li+ selectivity ≈48.6). Meanwhile, it also allows preferential transport for cations, the resulting membranes exhibit a K+ /Cl- selectivity of 76 and a H+ /Cl- selectivity of 59.3. The synergistic effects of steric hindrance and electrostatic interactions imposing a higher energy barrier for Cl- or Li+ across nanopores lead to ultra-selective H+ or K+ transport. Further, the functionalized graphene nanopores generate a power density of 25.3W m-2 and a conversion efficiency of 33.9%, showing potential application prospects in energy conversion. The theoretical studies quantitatively match well with the experimental results. The feasible preparation of functionalized graphene nanopores paves the way toward direct investigation on ion transport mechanism and advanced design in devices.

Unusual modifications of protein biomarkers expressed by plasmid, prophage, and bacterial host of pathogenic Escherichia coli identified using top‐down proteomic analysis

RationalePathogenic bacteria often carry prophage (bacterial viruses) and plasmids (small circular pieces of DNA) that may harbor toxin, antibacterial, and antibiotic resistance genes. Proteomic characterization of pathogenic bacteria should include the identification of host proteins and proteins produced by prophage and plasmid genomes.MethodsProtein biomarkers of two strains of Shiga toxin–producing Escherichia coli (STEC) were identified using antibiotic induction, matrix‐assisted laser desorption/ionization tandem time‐of‐flight (MALDI‐TOF‐TOF) tandem mass spectrometry (MS/MS) with post‐source decay (PSD), top‐down proteomic (TDP) analysis, and plasmid sequencing. Alphafold2 was also used to compare predicted in silico structures of the identified proteins to prominent fragment ions generated using MS/MS‐PSD. Strain samples were also analyzed with and without chemical reduction treatment to detect the attachment of pendant groups bound by thioester or disulfide bonds.ResultsShiga toxin was detected and/or identified in both STEC strains. For the first time, we also identified the osmotically inducible protein (OsmY) whose sequence unexpectedly had two forms: a full and a truncated sequence. The truncated OsmY terminates in the middle of an α‐helix as determined by Alphafold2. A plasmid‐encoded colicin immunity protein was also identified with and without attachment of an unidentified cysteine‐bound pendant group (~307 Da). Plasmid sequencing confirmed top‐down analysis and the identification of a promoter upstream of the immunity gene that is activated by antibiotic induction, that is, SOS box.ConclusionsTDP analysis, coupled with other techniques (e.g., antibiotic induction, chemical reduction, plasmid sequencing, and in silico protein modeling), is a powerful tool to identify proteins (and their modifications), including prophage‐ and plasmid‐encoded proteins, produced by pathogenic microorganisms.

Ion migration mediated high Seebeck effect in halide perovskites and application in infrared detection

Thermoelectric materials play an important role in thermopower systems, thermal sensing and infrared photo-thermoelectric imaging. Ionic thermoelectric materials have recently attracted attentions considering their relatively high Seebeck coefficient. However, the ionic thermoelectric materials have to use liquid or hydrogels for ion conduction, and are susceptible to leakage, evaporation and portability issues. Metal halide perovskites possess low thermal conductivity and prominent ion migration characteristics, making them theoretically suitable candidates for thermoelectric conversion. Here we present the first-ever study of the ionic thermoelectric properties in typical solid perovskite composition MAPbI3, revealing an extremely high Seebeck coefficient of 35.7 mV/K. Furthermore, the assembled photo-thermoelectric detector of carbon/MAPbI3 single crystal/carbon demonstrated a high response (0.58 V/W) toward infrared light and the imaging test was well resolved. This research provides a novel avenue to investigate efficient thermoelectric devices based on ionic and electronic mixed conductors and develop photo-thermoelectric applications.

Assignment of product ions produced from ciguatoxin-3C provides a deep insight into the fragmentation mechanism of polycyclic ether compounds.

Marine polycyclic ethers have drawn attention owing to their unique chemical structures and involvement in food poisoning and fish killing. To study structural diversity, we performed a structural assignment of product ions produced from a representative ladder-shaped polycyclic ether, ciguatoxin-3C, and elucidated the mechanism of generation. The product ions used for the structural assignment were produced from a precursor ion [M + H]+ using liquid chromatography/quadrupole time-of-flight mass spectrometry, by employing an atmospheric pressure chemical ionization source. Three charged sites were considered at both terminals of a molecule. Typical charge-remote fragmentation was produced at the respective charge sites, yielding a hybrid spectrum. C-C bonds bordering two ethers could cleave and trigger the fission of two other bonds. Prominent ions indicating the serial loss of water molecules resulted from the simultaneous deprivation of ethereal oxygen and hydrogen atoms. The resultant double bonds formed long chains of conjugated polyenes, which stabilized charge via resonance. Three alternative charge sites produce a hybrid spectrum. The simultaneous fission of three bonds was explained. For the first time, intense ions due to serial dehydration were explained by the elimination of ether oxygen atoms and the subsequent conjugation of double bonds. All product ions were considered by the structural features of polycyclic ether that facilitates the formation of conjugated polyenes.

Chemical and microbial evaluation of water of Rupa lake

Analysis of chemical and microbial features of Rupa lake water was carried out in summer season by adopting accepted analytical techniques. Water samples were collected at 28°C, and on-site observations were made for features like colour, odour, pH, transparency, dissolved oxygen, and free carbon dioxide. In the laboratory, the concentration of prominent mineral ions and microbial contamination were measured using accepted analytical techniques. Transparency of lake water was noted 91cm and electrical conductivity 41 µs/cm indicating the presence of suspended particulate at moderately higher concentration. This water is slightly alkaline with pH of 7.2 that is accounted by domination of alkali and alkaline metal ions. Presence of nitrogenous species mainly ammonium and nitrate in excess amount has detected to be major reason for rapid eutrophication in the lake. Analysis of Rupa lake water has shown the considerable presence of phosphate and sulphate which have added to the hardness 130 mg/L of the water as well. On the top of this fairly higher concentration of free carbon dioxide indicates presence of organic wastes in association with decaying matters. Domestic sewage discharge, the use of pesticides and fertilizers in agricultural areas, as well as other solid waste dumps has caused microbial contamination and the biggest dangers to the viability of Rupa lake. The risk of contamination and the eutrophication process needs to be managed by creating public awareness [1].The study shows that water quality of Rupa lake is contaminated for drinking but adequately suitable for all aquatic life and ecological balance.

Toxin and phage production from pathogenic E. coli by antibiotic induction analyzed by chemical reduction, MALDI-TOF-TOF mass spectrometry and top-down proteomic analysis.

Shiga toxin-producing Escherichia coli (STEC) are an on-going threat to public health and agriculture. Our laboratory has developed a rapid method for identification of Shiga toxin (Stx), bacteriophage and host proteins produced from STEC. We demonstrate this technique on two genomically sequenced STEC O145:H28 strains linked to two major outbreaks of foodborne illness occurring in 2007 (Belgium) and 2010 (Arizona). Our approach is to induce expression of stx, prophage and host genes by antibiotic exposure, chemically reduce samples and identify protein biomarkers from unfractionated samples using MALDI-TOF-TOF, tandem mass spectrometry (MS/MS) and post-source decay (PSD). The protein mass and prominent fragment ions were used to identify protein sequences using top-down proteomic software developed in-house. Prominent fragment ions are the result of polypeptide backbone cleavage (PBC) resulting from the aspartic acid effect fragmentation mechanism. The B-subunit of Stx and acid-stress proteins HdeA and HdeB were identified in both STEC strains in their intramolecular disulfide bond-intact and reduced states. In addition, two cysteine-containing phage tail proteins were detected and identified from the Arizona strain but only under reducing conditions which suggests that bacteriophage complexes are bound by intermolecular disulfide bonds. An acyl carrier protein (ACP) and a phosphocarrier protein (HPr) were also identified from the Belgium strain. ACP was post-translationally modified with attachment of a phosphopantetheine linker at residue S36. The abundance of ACP (plus linker) was significantly increased upon chemical reduction suggesting the release of fatty acids bound to the ACP + linker at a thioester bond. MS/MS-PSD revealed dissociative loss of the linker from the precursor ion as well as fragment ions with and without the attached linker consistent with its attachment at S36. This study demonstrates the advantages of chemical reduction in facilitating the detection and top-down identification of protein biomarkers of pathogenic bacteria.

Potassium Channels in Parkinson's Disease: Potential Roles in Its Pathogenesis and Innovative Molecular Targets for Treatment.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by selective loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) region of the midbrain. The loss of neurons results in a subsequent reduction of dopamine in the striatum, which underlies the core motor symptoms of PD. To date, there are no effective treatments to stop, slow, or reverse the pathologic progression of dopaminergic neurodegeneration. This unfortunate predicament is because of the current early stages in understanding the biologic targets and pathways involved in PD pathogenesis. Ion channels have become emerging targets for new therapeutic development for PD due to their essential roles in neuronal function and neuroinflammation. Potassium channels are the most prominent ion channel family and have been shown to be critically important in PD pathology because of their roles in modulating neuronal excitability, neurotransmitter release, synaptic transmission, and neuroinflammation. In this review, members of the subfamilies of voltage-gated K+ channels, inward rectifying K+ channels, and Ca2+-activated K+ channels are described. Evidence of the role of these channels in PD etiology is discussed together with the latest views on related pathologic mechanisms and their potential as biologic targets for developing neuroprotective drugs for PD. SIGNIFICANCE STATEMENT: Parkinson's disease (PD) is the second most common neurodegenerative disorder, featuring progressive degeneration of dopaminergic neurons in the midbrain. It is a multifactorial disease involving multiple risk factors and complex pathobiological mechanisms. Mounting evidence suggests that ion channels play vital roles in the pathogenesis and progression of PD by regulating neuronal excitability and immune cell function. Therefore, they have become "hot" biological targets for PD, as demonstrated by multiple clinical trials of drug candidates targeting ion channels for PD therapy.

Competition between Slc7a5 and LMAN2 for modulation of Kv1.2 gating.

The voltage-gated potassium channel Kv1.2 is a prominent ion channel in the CNS, where it regulates electrical activity. Kv1.2 structure and function are well understood, but its regulation by auxiliary proteins has not been widely studied. We identified novel regulators of Kv1.2 by a mass spectrometry approach, including the neutral amino acid transporter Slc7a5, which causes a dramatic hyperpolarizing shift of channel activation. In contrast, LMAN2 is a recently identified candidate regulator that has the opposite effect on gating: large depolarizing voltages are required to activate Kv1.2 channels co-expressed with LMAN2. In this study, we characterized the functional interaction between LMAN2 and Slc7a5 on Kv1.2 gating properties, and identified key structural elements that underlie sensitivity to either regulator. When LMAN2 and Slc7a5 are expressed together, Kv1.2 activation exhibits a bimodal voltage-dependence, suggesting two distinct populations of channels regulated either by LMAN2 or Slc7a5, but not both. Kv1.5 is a close homolog of Kv1.2, but insensitive to both LMAN2 and Slc7a5. Using a Kv1.2:1.5 chimeric approach, we identified the S1 segment of the voltage sensing domain (VSD) as essential for Slc7a5 sensitivity, and the S2-S3 linker of the VSD for LMAN2 sensitivity. By replacing either segment with sequence from Kv1.5, modulation by the corresponding regulator was selectively abolished. Replacement of the S1-S3 segment of Kv1.2 with sequence from Kv1.5 rendered the channel insensitive to both forms of regulation. These results suggest that Slc7a5 and LMAN2 compete for interaction with the Kv1.2 voltage sensor, leading to complex voltage-dependence of channel activity when both regulators are present in the cell. Although the structural basis for this modulation remains uncertain, Kv1.2 clearly exhibits a propensity for modulation over a wide range of voltages.

Investigation of Secondary Metabolites from Marine‐Derived FungiAspergillus

AbstractMarine fungiAspergillus flavipesandA. terreuswere investigated for secondary metabolites using electrospray ionization‐quadrupole time‐of‐flight mass spectrometry (ESI‐QTOF MS) analysis. The ESI‐MS analysis showed thatA. flavipesshowed molecular ion peaks for compounds, terrein(1), butyrolactone I(2), butyrolactone I‐carboxylic acid(3), butyrolactone III(4), while,A. terreushad additional presence of new compound aspernolide Q(5)with absence of compound(3). By using tandem mass spectrometry data, the prominent fragment ions helped in the establishing the structure of compounds(2‐5). Further, chemical transformation of butyrolactone I to butyrolactone III and aspernolide Q were carried out followed by NMR analysis which strongly suggested their structures. The evaluation of salt stress experiment ofA. terreusculture medium affected the production of major bioactive metabolites, terrein and butyrolactone I(2). The HPLC analysis showed that culture produces high amount of terrein at 35 ‰, while, maximum production of butyrolactone I was observed in fresh water i. e. 0‰. The study highlighted an importance of salinity in producing these metabolites where, terrein and butyrolactone I could be produced in equal ratio at 18‰. Importantly, we have demonstrated that using this fungal strain and by growing in medium at specific salinity could be way forward for commercial production of these bioactive compounds.

Sources and processes of water-soluble and water-insoluble organic aerosol in cold season in Beijing, China

Abstract. Water-soluble and water-insoluble organic aerosol (WSOA and WIOA) constitute a large fraction of fine particles in winter in northern China, yet our understanding of their sources and processes are still limited. Here we have a comprehensive characterization of WSOA in cold season in Beijing. Particularly, we present the first mass spectral characterization of WIOA by integrating online and offline organic aerosol measurements from high-resolution aerosol mass spectrometer. Our results showed that WSOA on average accounted for 59 % of the total OA and comprised dominantly secondary OA (SOA, 69 %). The WSOA composition showed significant changes during the transition season from autumn to winter. While the photochemical-related SOA dominated WSOA (51 %) in early November, the oxidized SOA from biomass burning increased substantially from 8 % to 29 % during the heating season. Comparatively, local primary OA dominantly from cooking aerosol contributed the major fraction of WSOA during clean periods. WIOA showed largely different spectral patterns from WSOA which were characterized by prominent hydrocarbon ions series and low oxygen-to-carbon (O/C = 0.19) and organic mass-to-organic carbon (OM/OC = 1.39) ratios. The nighttime WIOA showed less oxidized properties (O/C = 0.16 vs. 0.24) with more pronounced polycyclic aromatic hydrocarbons (PAHs) signals than daytime, indicating the impacts of enhanced coal combustion emissions on WIOA. The evolution process of WSOA and WIOA was further demonstrated by the triangle plot of f44 (fraction of m/z 44 in OA) vs. f43, f44 vs. f60, and the Van Krevelen diagram (H/C vs. O/C). We also found more oxidized WSOA and an increased contribution of SOA in WSOA compared with previous winter studies in Beijing, indicating that the changes in OA composition due to clean air act have affected the sources and properties of WSOA.

Abnormal levels of mitochondrial Ca2+ channel proteins in plasma neuron-derived extracellular vesicles of early schizophrenia.

Structural alterations or quantitative abnormalities of some mitochondrial ion channels and exchangers are associated with altered neuronal functions and increased susceptibility to mental illness. Here we have assessed levels of functionally prominent mitochondrial calcium ion channel proteins in plasma neuron-derived extracellular vesicles (NDEVs) of living patients with first episodes of psychosis (FP) and matched controls (Cs). NDEVs were enriched with an established method of precipitation and immunoabsorption by anti-human CD171 neural adhesion protein (L1CAM) antibody and extracted proteins quantified with ELISAs. CD81 exosome marker-normalized NDEV levels of leucine zipper EF-hand containing transmembrane 1 protein (LETM1), transient receptor potential cation channel subfamily M, member 4 (TRPM4), and solute carrier family 8 member B1 (SLC24A6) or mitochondrial Na+ /Ca2+ exchanger (NCLX) were significantly lower for FP patients (n=10) than Cs (n=10), whereas NDEV levels of voltage-dependent L-type calcium channel subunit α-1C (CACNA-1C) were significantly higher for FP patients than Cs. Abnormal structures or mitochondrial levels of LETM1, NCLX, and CACNA-1C have been linked through analyses of individual proteins, genome-wide association studies, and whole exome protein-coding sequence studies to neurodevelopmental disorders, mental retardation, schizophrenia, and major depressive diseases. A greater understanding of the altered calcium homeostasis in schizophrenia, that is attributable to underlying mitochondrial calcium channel abnormalities, will lead to improved diagnosis and treatment.

Chromatographic Fractionation of Penicillium polonicum Fermentation Metabolites in Search of the Nephrotoxin(s) for Rats.

Complex renal histopathological changes in rats, in silent response to dietary contamination with wheat moulded by a common Penicillium from the Balkans, have long eluded attribution of a causal toxin. So far, water-soluble amphoteric glyco-peptides seem responsible, at least for the nuclear pyknoses in nephron epithelia after several days of dietary exposure. Recently, refined histology analysis has diagnosed pyknosis as apoptosis, and followed the finding through application of medium-pressure liquid chromatography, anion exchange and silica layer chromatography to fractionate a water/alcohol-soluble extract of a fungal fermentation on wheat. Proline was revealed, with other amino acids, in acid hydrolysate of the fermentation extract. Application of mass spectrometry has recognized prominent ions (m/z 550 and 564) correlated with fragmentations consistent with a terminal proline moiety for the putative toxins, coupled with other structural fragments and correlated with apoptosis. Use of 14C-proline in probing Penicillium polonicum fermentation to aid isolation of the new potential toxins, along with application of gel electrophoresis, may further aid characterization of the apoptosis toxin(s). The present focus on proline peptides in mycotoxicosis fits easily with their increasingly recognised pharmacological activity associated with proline’s rigid secondary amine structure, which causes conformational contortion in peptides. Nevertheless, there remains the striking rat renal karyocytomegaly by P. polonicum, for which there is yet no causative mycotoxin.

An integrated strategy for the systematic chemical characterization of Salvianolate lyophilized injection using four scan modes based on the ultra-high performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry

Salvianolate lyophilized injection (SLI), a freeze-dried powder injection derived from aqueous extract of S. miltiorrhiza, is therapeutically used to treat the syndrome of blood stasis and collateral blockage during the recovery period after stroke. To date, it has remained a significant challenge to comprehensively characterize the compounds of SLI, particularly the minor components with potential bioactivities, in one sample injection analysis. Using an integrative four scan modes approach coupled with ultra-high performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry (UHPLC-QTRAP-MS/MS), we propose a novel, sensitive, and simple strategy for systematic and rapid profiling of the chemical components of SLI. First, an in-house database of constituents from the water-soluble extract of Danshen was created. Second, the fragmentation behaviors of the representative components in SLI were obtained using the untargeted scan mode enhanced MS (EMS)-information dependent acquisition (IDA)-enhanced product ion (EPI). The specific fragments acquired were then utilized to conduct precursor ion (Prec) and neutral loss (NL)-IDA-EPI scans. Following that, a sensitive predictive multiple reaction monitoring (pMRM)-IDA-EPI scan method with 454 transitions was developed based on the prominent fragment ions and plausible predictions. A total of 171 compounds were tentatively identified from SLI. Among them, 27 minor components have not been previously reported. This strategy allows most isomeric compounds at trace levels to be readily distinguished and annotated. Finally, 15 batches of 13 representative components in SLI selected by the qualitative results were accurately quantified. Salvianolic acid A (Sal A), Sal B, Sal D, lithospermic acid (LA), and rosmarinic acid (RA) were proved to be the predominant constituents. Sal B had the highest amount (195.08–350.46 μg·mg‐1), followed by LA, Sal A, Sal D, and RA. Moreover, these 15 batches of samples showed good uniformity, and no abnormal batches existed. These results suggest that this novel strategy can accelerate the identification of undiscovered chemical components and serve as an alternative method for in-depth profiling of compounds in other traditional Chinese medicines (TCMs).

Maximized ion accessibility in the binder-free layer-by-layer MXene/CNT film prepared by the electrophoretic deposition for rapid hybrid capacitive deionization

Two-dimensional (2D) pseudo-capacitive material MXene has attracted great consideration in the capacitive deionization (CDI) process for its prominent ion storage capacity and reversible ion intercalation/deintercalation mechanism. Unfortunately, the accessibility of active sites for ion intercalation is greatly limited by the self-stacking of MXene flakes for the strong van der Waals forces. What’s worse, the addition of binder in the MXene electrode prepared by the conventional coating method for CDI blocks ion accessibility channels and increases ion transfer resistance, hindering the efficient capture of ions by electrodes. Herein, the binder-free layer-by-layer MXene/CNT film electrode is flexibly constructed by the electrophoretic deposition (EPD) method to effectively alleviate the above situation. In this design, CNT not only acts as the conductive interlayer spacer to restrain MXene nanosheets self-stacking but also builds interconnected conductive channels to minimize the tortuosity of charge transport path. Furthermore, the binder-free EPD method for electrode preparation maximizes ion accessibility to ion intercalation sites, simplifies ion transfer path, accelerates ion transfer rate, and improves ion diffusion kinetics. Consequently, the resulting deposited MXene/CNT film electrode displays a dominant specific capacitance (178 F g−1), reduced charging resistance, rich Na+ diffusion channels, and maximized Na+ diffusion coefficient (5.8 × 10−8 cm2 s−1). Thus, the asymmetric hybrid CDI cell CNT//MXene/CNT adopting the deposited CNT electrode as anode and deposited MXene/CNT film electrode as cathode delivers the prominent desalination capacity (34.5 mg g−1), rapid average desalination rate (3 mg g−1 min−1), low energy consumption (0.26 kWh kg−1-NaCl), and excellent cyclic intercalation-deintercalation stability (89% retention rate). This rational design provides an alternative strategy to solve the tricky problems of MXene and develops new approach towards maximized ion accessibility in CDI field.

A coupling technology of capacitive deionization and carbon-supported petal-like VS2 composite for effective and selective adsorption of lead (II) ions

• ZAC@VS 2 disperses the modified tubular carbon material in VS 2 lamella. • ZAC@VS 2 has improved active sites and conductivity. • ZAC@VS 2 shows considerable specific capacitance and low charging resistance. • ZAC@VS 2 electrode displays a prominent heavy metal ions of lead (II) adsorption capacity and rate. • ZAC@VS 2 electrode has the superior ion selectivity to Pb 2+ than Fe 3+ and Na ± . The conventional separation technologies, like chemical precipitation and adsorption processes, cannot quickly and selectively separate and recycle heavy metal ions from waste. Due to its rich sulfur content and excellent electrical conductivity, vanadium disulfide is a potential material for effectively removing lead from wastewater. The vanadium disulfide material with selective adsorption ability was introduced into CDI technology to construct a coupling technology with both advantages. The N -doped modified ZIF@vanadium disulfide (ZAC@VS 2 ) composites were successfully synthesized by hydrothermal method. Electrosorption experiments show that ZAC@VS 2 material presents the remarkable saturated adsorption capacity to lead(II) ions (239.52 mg/g) in the 500 mg/L PbCl 2 solution. In the triplex blend system (Fe 3+ /Pb 2+ /Na + ) with each solute density of 100 mg/L, the saturated adsorption efficiency of 85.4% to Pb 2+ can still be maintained. In addition, compared with the Langmuir(R 2 =0.873) adsorption isotherm model, the Freundlich model (R 2 =0.922) can be better used to fit the adsorption process, which proves that the adsorption process is multilayered and heterogeneous. XPS tests and competitive adsorption experiments show that the electric double layer (EDL) and complexation together promote the selective adsorption of heavy metal ions by ZAC@VS 2 . ZAC@VS 2 composite electrode shows excellent performance in the removal of lead ions in battery waste liquid, indicating the potential of introducing ZAC@VS 2 into CDI to remove lead ions.

3D hierarchical biobased gel electrolyte with superior ionic conductivity and flame resistance for suppressing lithium dendrites via alloying and sieving mechanisms

The unmanageable growth of lithium dendrites has severely restrained the application of Li mental anode for higher energy density batteries. To tackle the issue of lithium dendrites, a novel dual strategy of “dead lithium” dissipation via the lithium alloying and sieving effect were developed to endow a biobased gel polymer electrolyte (GPE) with excellent performance in effectively suppressing the growth of lithium dendrite at high current density . Specifically, based on the electrospun cellulose acetate/poly (lactic acid)/black phosphorus-bismuth sulfide (PCA/Bi 2 S 3 -BP) membranes, 3D-hierarchical structure with numerous polar functional groups was applied to improve the electrochemical efficiency and mechanical flexibility of biobased gel electrolytes. The dual mechanisms of alloying reactions and sieving effect from Bi 2 S 3 and BP was for the first time applied to disrupt dendrite growth from the bottom-up. Furthermore, the puckered “honeycomb” structure of BP nanosheets provided a specific mass route for directional Li + transmission and could immobilize PF6- for the Li-ion transference number improvement. The as-prepared GPE presented a superior lithium ionic conductivity of 8.37 × 10 −3 S cm −1 , together with prominent lithium ion transference up to 0.64 at 25 °C. The assembled Li/GPE/NCM523 batteries by PCA/Bi 2 S 3 -BP gel polymer electrolyte displayed initial discharge capacity of 141.68 mAh g −1 with capacity retention of 90.23% after 200 cycles at 1C. Therefore, PCA/Bi 2 S 3 -BP GPE with green skeleton materials demonstrated its promising application in high electrochemical performance and safety Li mental batteries.

Elucidation of double-bond positions of polyunsaturated alkenes through gas chromatography/mass spectrometry analysis of mono-dimethyl disulfide derivatives.

Derivatization with dimethyl disulfide (DMDS) followed by gas chromatography/mass spectrometry (GC/MS) analysis is a well-established method for locating double-bond position on the alkyl chain of mono-unsaturated compounds such as alkenes. For alkenes containing more than one double bond, however, the conventional DMDS derivatization approach forms poly- or cyclized DMDS adducts whose mass spectra are difficult to interpret in terms of double-bond positions. In this study, we report an efficient experimental procedure to produce mono-DMDS adducts for polyunsaturated alkenes with two to six double bonds. GC/MS analyses of these mono-DMDS adducts yield highly characteristic mass fragments, allowing unambiguous assignments of double-bond positions on the alkyl chain. We also apply our new approach (i.e., preferential formation of mono-DMDS adducts during derivatization with DMDS) to determine the double-bond positions of unsaturated alkenes produced by laboratory cultured Isochrysis litoralis, a haptophyte algal species. Alkenes from different sources were derivatized with DMDS at 25°C for 20 to 160 min. The mass spectra of mono-DMDS adducts were obtained by GC/EI-MS analysis of reaction products which contain chromatographically resolved mono-DMDS adducts. Mass spectra of corresponding mono-DMDS adducts contain prominent diagnostic ions that allow a conclusive elucidation of double-bond positions. In culture samples of Isochrysis litoralis, a series of novel mono- to tri-unsaturated C31 alkenes (9-C31:1 , 6,9-C31:2 , 6,22-C31:2 , 6,25-C31:2 , 9,22-C31:2 , 6,9,25-C31:3 ) were discovered for the first time. A highly efficient DMDS derivatization approach is developed to yield abundant mono-DMDS adducts of polyunsaturated alkyl alkenes for elucidating double-bond positions using GC/MS.