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Catechol pollutants (CATPs) serving as chelating agents could coordinate with many metal ions to form various CATPs-metal complexes. Little information is available on the effects of complexation of metal ions on CATPs degradation. This work presents a systematical study of •OH-mediated degradation of catechol and catechol-metal complexes over the whole pH range in advanced oxidation processes (AOPs). Results show that the pH-dependent complexation of metal ions (Zn2+, Cu2+, Ti4+ and Fe3+) promotes the deprotonation of catechol under neutral and even acidic conditions. The radical adduct formation (RAF) reactions are both thermodynamically and kinetically favorable for all dissociation and complexation species, and OH/ O− group-containing C positions are more vulnerable to •OH attack. The kinetic results show that the complexation of the four metal ions offers a wide pH range of effectiveness for catechol degradation. At pH 7, the apparent rate constant (kapp) values for different systems follow the order of catechol+Ti4+ ≈ catechol+Zn2+ > catechol+Cu2+ > catechol+Fe3+ > catechol. The mechanistic and kinetic results would greatly improve our understanding of the degradation of CATPs-metal and other organics-metal complexes in AOPs. The toxicity assessment indicates that the •OH-based AOPs have the ability for decreasing the toxicity and increasing the biodegradability during the processes of catechol degradation.

Aim and Objective: Europium (Eu(III))isa rare-earth metal, the softest, least dense, and most volatile member of lanthanides. It is greatly applied in control rods of nuclear reactors. Although various extraction methods of Eu(III)have been reported, we present a novel mixture ofeasily available extractants in optimizedexperimental conditions to extract it efficiently, quickly, and cost-effectively. Materials and Methods: Physical-chemical conditions (e.g. pH, equilibration time, temperature, europium concentration, extractants concentration, presence of specific metal ions) were optimized. The extractantspicrolonic acid (HPA) and di-n-butylsulfoxide (DBSO) were thoroughly mixed at equal concentrationin chloroform. Standard Eu(III) solution was used for method accuracy.Reagent blank was prepared under identical conditions but without metal ions.Using the metallochromic dye arsenazoIII as blank, absorbance of Eu(III) was measured spectrophotometricallyat 651 nm. Distribution ratio (i.e.Eu(III) concentration in aqueous phase before and after extraction) defined the extraction yield. Results: HPA/DBSO mixture (0.01 M)had a synergistic effect on Eu(III) extraction (1.19×10-5 mole/dm3) achieving a maximum yield (≥99%) at pH2, during 5 minutes equilibration,atroom temperature.Eu(III) extraction was reduced depending on the nature but not on the metal ions concentration. Extractants could be recycled four times without consequent degradation. Deionized water (dH2O) was the best strippantbesides its availability and low-cost. The composition of the extracted adduct was defined as Eu(PA)3.2DBSO. Conclusion: This alternative method was stable, simple, rapid, cost-effective, reliable, accurate and sensitive.It could be used forEu(III) extraction and refining on a pilot plant scale.

Aims The adsorption of lead ions from aqueous solution by macroporous Ca-alginate-lignin (MCAL) beads immobilized with Clostridium tyrobutyricum and free strains was evaluated. Methods and Results The effects of different factors including pH, adsorption time, adsorbent dosage and initial concentration of lead ions were explored. Different characterization methods were used to evaluate the adsorption process of lead ions. Meanwhile, the adsorption kinetics models and adsorption isotherm models were applied. The fitting results showed that the adsorption behaviour of C. tyrobutyricum immobilized in MCAL beads and free strains was better described by the pseudo-second-order kinetic model and the adsorption process followed the Langmuir isotherm model. The maximum biosorption of lead ions by C. tyrobutyricum immobilized in MCAL beads and free strains was 144.9 and 106.4 mg/g respectively. Conclusions The C. tyrobutyricum immobilized in MCAL beads proved to be practicable and had better adsorption effects on lead ions compared with the free strains. Significance and Impact of the Study The paper demonstrated a new insight and strategy for the effective treatment of lead ions from aqueous solutions by the novel function of C. tyrobutyricum.

Polymer (anionic polyacrylamide, APAM) flooding produced wastewater has a relatively high degree of mineralization and abundant ionic species. A comprehensive and systematic investigation of the influence of ion identity on APAM-induced membrane fouling is extremely necessary but has not been conducted to date. A comparative investigation was performed herein to reveal the underlying mechanisms of the influence of Na+ and Ca2+ (1000 mg/L) on APAM-induced membrane fouling in the adsorption and microfiltration (MF) processes. Na+ and Ca2+ exhibited contrasting influences on the filtration efficiency, cleaning efficiency, and fouling resistance. Compared to Na+, Ca2+ promoted reversible fouling and the formation of a loose cake layer; moreover, a higher removal rate and flux recovery were achieved. Additionally, simulations based on adsorption kinetic and membrane fouling models, and a series of microscopic analyses were performed to validate the contradictory influences. During the APAM-based MF process, the membrane fouling was effectively mitigated at the applied ionic strength because of the stronger hydration repulsive force generated by hydrated Ca2+ compared to that by Na+. This study provides vital guidance for membrane fouling control in the microfiltration of polymer flooding produced wastewater.

Hypothesis One prevailing method to construct excellent temperature tolerance/long-lasting moisture hydrogels is to couple the original hydrogel networks with freezing-tolerant/moisture retaining agents, including ionic liquids, inorganic salts, zwitterionic osmolytes, and polyhydric alcohols. Among them, organohydrogels have shed new light on the development of ionic skins with long-term usability and stable sensing performance at subzero temperatures due to their long-lasting water retention and anti-freezing capability. Experiments We report a dual network organohydrogel by doping conductive ZnSO4 into the double network hydrogel of polyvinyl alcohol-polyacrylamide (PVA-PAM) with subsequent immersing in a mixed solvent of ethylene glycol (EG) and H2O. The anti-freezing and moisture retaining abilities of the PVA/PAM/Zn/EG (PPZE) organohydrogel were studied and the sensing performances of the PPZE organohydrogel-based ionic skin were investigated. Findings The organohydrogel exhibits a high conductivity (0.44 S m−1), excellent fatigue resistance and exceptional moisture retaining ability with more than 99.3% of the initial weight retention after 31 days storage at ambient temperature. Importantly, the PPZE organohydrogel-based ionic skin shows an ultra-low temperature anti-freezing ability and remains flexibility and sensing capability with a high sensitivity (signal response time ∼ 0.23 s) even at -50 °C. The PPZE organohydrogel demonstrates a tremendous potential in artificial skin and health monitoring.

Nitrophenols (NPs) are widely used in industries and highly toxic to ecological environment and human health. Because aminophenols (APs) are important chemicals, catalytic reduction of NPs via efficient and environment-friendly strategies is of great importance. Herein, we developed a green photocatalysis route to efficiently convert NPs to APs using a Fe (II) modified graphitic carbon nitride (g-C3N4) photocatalyst, where phenanthroline units were employed to bridge Fe (II) and carbon nitride framework. The optimized sample P-CN-8-Fe presented significantly improved absorption of visible light, separation of photogenerated charges and carrier transportation in comparison with the pristine g-C3N4 and the modified samples of CN-Fe and P-CN-8. Accordingly, the P-CN-8-Fe showed a high conversion (97%) of p-nitrophenol (p-NP) to p-aminophenol (p-AP) under 2 h visible light irradiation, and meanwhile possessed high photocatalytic durability. Its high activity was also demonstrated through photocatalytic reduction of other NPs and nitrobenzene compounds. Finally, a possible mechanism was proposed for the photocatalytic reduction of p-NP by P-CN-8-Fe. This work provides an effective approach to prepare Fe (II) modified g-C3N4 through the bridging effect of phenanthroline group, which is a potential visible light driven photocatalyst for reduction of nitrobenzene derivatives.

A gamma-pyrone derivative, comenic acid, activates the opioid-like receptor-mediated signaling pathway that modulates the NaV1.8 channels in the primary sensory neuron membrane. These channels are responsible for the generation of the nociceptive signal; therefore, gamma-pyrones have great therapeutic potential as analgesics, and this effect deserves a deeper understanding. The novelty of our approach to the design of a medicinal substance is based on a combination of the data obtained from living neurons using very sensitive physiological methods and the results of quantum chemical calculations. This approach allows the correlation of the molecular structure of gamma-pyrones with their ability to evoke a physiological response of the neuron. Comenic acid can bind to two calcium cations. One of them is chelated by the carbonyl and hydroxyl functional groups, while the other forms a salt bond with the carboxylate anion. Calcium-bound gamma-pyrones have fundamentally different electrostatic properties from free gamma-pyrone molecules. These two calcium ions are key elements involved in ligand-receptor binding. It is very likely that ion-ionic interactions between these cations and anionic functional groups of the opioid-like receptor activate the latter. The calculated intercationic distance of 9.5 Å is a structural criterion for effective ligand-receptor binding of calcium-bound gamma-pyrones.

Hierarchical dendrimer-based polyion complex (PIC) vesicles with multiple compartments have attracted considerable attention as functional delivery vehicles and nano-carriers. Formation of these vesicles relies on the electrostatic assembly of asymmetric polyelectrolytes, namely branched dendrimers with linear polyion-neutral diblock copolymers. However, successful incorporation of dendrimers in vesicle lamellae is challenging due to the compact structure of dendrimers, and therefore, vesicles reported so far are prepared mainly with low generation dendrimers which lack the cavity required for carrier functions. Here, we present a new assembly combination of amine-terminated dendrimer polyamidoamine (PAMAM) with polyion-neutral diblock copolymer poly (styrene sulphonate-b-ethylene oxide) (PSS-b-PEO). The strong charge interaction between the building blocks leads to stable and well-defined PIC vesicles that can tolerate not only different PSS block lengths but, more importantly, also different dendrimer generations from 2 to 7. As a consequence, high generation dendrimers with a cavity can be packed in the vesicle wall, and one obtains hierarchical PIC vesicles with multiple compartments, namely the dendrimer cavity for loading small hydrophobic cargo, and the vesicle lumen for encapsulating hydrophilic macromolecules. Our study demonstrates that combining proper building blocks enables to manipulate the charge interactions, which is essential for controlling the dendrimer packing and the formation of PIC vesicles. These findings should be helpful for understanding the assembly of asymmetric (linear / branched) polyelectrolyte complexes, as well as for designing new hierarchical PIC vesicles for controlled delivery of multiple active substances.

Excitatory amino acid transporters (EAAT) play a key role in glutamatergic synaptic communication. Driven by transmembrane cation gradients, these transporters catalyze the reuptake of glutamate from the synaptic cleft once this neurotransmitter has been utilized for signaling. Two decades ago, pioneering studies in the Kanner lab identified a conserved methionine within the transmembrane domain as key for substrate turnover rate and specificity; later structural work, particularly for the prokaryotic homologs GltPh and GltTk, revealed that this methionine is involved in the coordination of one of the three Na+ ions that are co-transported with the substrate. Albeit extremely atypical, the existence of this interaction is consistent with biophysical analyses of GltPh showing that mutations of this methionine diminish the binding cooperativity between substrates and Na+. It has been unclear, however, whether this intriguing methionine influences the thermodynamics of the transport reaction, i.e., its substrate:ion stoichiometry, or whether it simply fosters a specific kinetics in the binding reaction, which, while influential for the turnover rate, do not fundamentally explain the ion-coupling mechanism of this class of transporters. Here, studies of GltTk using experimental and computational methods independently arrive at the conclusion that the latter hypothesis is the most plausible, and lay the groundwork for future efforts to uncover the underlying mechanism.

Three derivatives of 1-aminopyrene are functionalized with 2-picolyl and 2-picolinyl groups and tested as fluorescent sensors for metal ions. The target compounds are successfully synthesized in 50 to 90% yields and characterized by 1 H-NMR, 13 C-NMR, and HRMS. The compound with an amino picolyl group (P1) exhibits an excellent selectivity towards Cu(II) ion as the fluorescent signal shifts from 433 to 630 nm. From a fluorescence titration experiment, the limit of detection for Cu(II) ion is estimated to 0.19 µM. That the fluorescence spectral shift by Cu(II) ion is reliant on the use of acetonitrile as a co-solvent and the results from cyclic voltammetry and UV-Vis spectroscopy suggest that the sensing mechanism involves a coordination complex between the P1, acetonitrile, and Cu(II) ion. Furthermore, this P1-Cu complex can also be used as a selective fluorescent sensor for PO43- ion with a detection limit of 0.44 µM.

Natural protein channels have evolved with exquisite structures to transport ions selectively and rapidly. Learning from nature to construct biomimetic artificial channels is always challenging. Herein we present a unimolecular transmembrane proton channel by quinoline-derived helix, which exhibited highly selective and ultrafast proton transport behaviors. This helix-based channel possesses a small luminal cavity of 1 A in diameter, which could efficiently reject the permeation of cations, anions or water molecules but only permits the translocation of protons owing to the size effect. The proton flow rate exceeded 107 H+ s-1 channel-1 and reached the same magnitude with gramicidin A. Mechanism investigation revealed that the directionally arrayed NH-chain inside the synthetic channel played a pivotal role during the proton flux. This work not only presented a helix-based channel with the smallest observable nanopore, but also unveiled an unexplored pathway for realizing efficient transport of protons via the consecutive NH-chain.

The world's interest now is focusing on the applying of the principles of sustainable development in managing natural resources, especially in managing freshwater, which is one of the greatest challenges the whole world face. In this paper, the illite ore was tested to remove the excess of iron and manganese from groundwater which is used for drinking and household purposes in Assiut. To accomplish this goal, the study was based on two directions. The first direction focused on achieving a physicochemical analytical survey for all the groundwater produced by wells in Assiut governorate, and its averages are plotted on GIS maps, to illustrate the difference in the concentrations of iron and manganese. However, the second direction focused on the preparation and examination of the modified illite ore, and it was characterized by using XRD, SEM, FT-IR, and XRF techniques. The results showed that the sodalite-bearing modified illite (SBMI) was able to remove the excess of iron and manganese from raw groundwater with the efficiency of 99% and 97%, respectively.

In this study, poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) dual-layer membranes filled with 0–3 wt% cellulose nanowhisker (CNWs) were fabricated with aim to remove metal ions from wastewater. An integrated method was employed in the membrane fabrication process by combining water vapor-induced and crystallization-induced phase inversions. The membrane thickness was measured in between 11 and 13 μm, which did not pose significant flux deviation during filtration process. The 3% CNW filled membrane showed prominent and well-laminated two layers structure. Meanwhile, the increase in CNWs from 0 to 3% loadings could improve the membrane porosity (43–74%) but reducing pore size (2.45–0.54 μm). The heat resistance of neat membrane enhanced by 1% CNW but decreased with loadings of 2–3% CNWs due to flaming behavior of sulphated nanocellulose. Membrane with 3% CNW displayed the tensile strength (23.5 MPa), elongation at break (7.1%), and Young's modulus (0.75 GPa) as compared to other samples. For wastewater filtration performance, the continuous operation test showed that 3% CNW filled membrane exhibited the highest removal efficiency for both cobalt and nickel metal ions reaching to 83% and 84%, respectively. We concluded that CNWs filled dual-layer membranes have potential for future development in the removal of heavy metal ions from wastewater streams.

In this study, zein and fucoidan-based composite nanoparticles were prepared by the antisolvent precipitation method. The effects of different calcium ion (Ca2+, 0–3.0 mM) concentrations on the stability of the composite nanosystems loaded with quercetin were studied under different conditions (pH, temperature, salt concentration, and ultraviolet light irradiation), and the composite nanoparticles were characterized. Electrostatic interactions, hydrogen bonding, and hydrophobic interactions are the main forces underlying the formation of composite nanoparticles. The addition of Ca2+ led to improved release of the active substances from the composite nanoparticles in simulated digestive solutions (especially when the Ca2+ concentration was 1.5 mM). The composite nanosystems based on alcohol-soluble proteins and anionic polysaccharides with added Ca2+ can be potentially applied for the delivery of active substances.

The K+ and Na+ levels in cells have a synergistic effect on many biological processes (BPs); therefore, the simultaneous detection of them is important. Here, we propose a novel Y-shaped DNA sensor for simultaneous monitoring of Na+ and K+ in extracellular microenvironments. The designed sensor contributed to the selective response to the above two ions. In addition, it performed the imaging of the above two ions on the cell surface in a real-time, on-site manner, which would shed more light on the association of the Na+/K+ content with regulatory BPs. We believe that this new strategy will be a promising tool to investigate the synergy of Na+/K+ in regulating different BPs.

BACKGROUND/AIM Carbon-ion radiotherapy has strong antitumor effects in X-ray-resistant tumors. However, the mechanisms underlying the strong antitumor effect, especially on metabolic alterations, are not fully elucidated. This study aimed to determine the effect of therapeutic carbon ions on metabolic alterations in cancer cells. MATERIALS AND METHODS Five human cancer cell lines were used in this study. The change in 333 metabolite levels in response to carbon ions was analyzed using gas chromatography-mass spectrometry. RESULTS Fifty-two metabolites were commonly detected in all cell lines. The levels of five metabolites significantly changed in four or more cell lines. Three of the five metabolites (i.e., 2-ketoglutaric acid, fumaric acid and 2-hydroxyglutaric acid) were associated with the TCA cycle. TCA cycle intermediates and the downstream oncometabolite 2-hydroxyglutaric acid were up-regulated by carbon ions. CONCLUSION We demonstrated for the first time that TCA cycle intermediates and 2-hydroxyglutaric acid are up-regulated after carbon-ion irradiation.

An extremely sensitive methodology for the determination of Ru was developed by coupling photochemical vapor generation (PVG) analyte introduction with inductively coupled plasma mass spectrometry (ICPMS). PVG was undertaken with a thin-film flow-through photoreactor in a medium comprising 8 M formic acid in the presence of 10 mg L⁻¹ Co²⁺ and 25 mg L⁻¹ Cd²⁺. The volatile product (presumably ruthenium pentacarbonyl) was generated in a flow injection mode, yielding an overall efficiency of 29% at a sample flow rate of 1.4 mL min⁻¹. The presence of both Co²⁺ and Cd²⁺ sensitizers enhanced PVG efficiency by 3,200-fold, permitting a 31 s irradiation time. Although enhanced efficiency (≈40%) could be obtained with increased Co²⁺ concentration, this was not suitable for routine use due to co-generation of cobalt carbonyl. Excellent repeatability (

A magnetic solid-phase microextraction (SPME) procedure was optimized using Fe3O4 nanoparticles (NPs) to preconcentrate and determine cobalt and copper in real samples using microsample injection system-flame atomic absorption spectrometry (MIS-FAAS). Recoveries over 95% for Co(II) and 80% for Cu(II) from 90 mL of sample buffered to pH 4.0 were obtained using 50 mg Fe3O4 NPs as the adsorbent and 0.5 mL of 0.5 mol L-1 HNO3 as the eluent. The extraction time was 10 min. The preconcentration factors for Co(II) and Cu(II) were 180. The detection limits for Co(II) and Cu(II) were 1.2 and 0.9 mu g L-1, respectively. The relative uncertainties and relative standard deviations were lower than 5.3% and 2.4%, respectively. The developed method was verified by analyzing TMDW-500 drinking water, NIST 1573a Tomato leaves, and NCS DC 78302 Tibet soil as standard reference materials. The spiking experiments provided recoveries exceeding 95%. The method was applied to determine cobalt and copper in water, soil, tea infusion, and vegetable samples.

Gangliosides are the most abundant glycolipid among eukaryotic cell membranes and consist of a glycan head moiety containing one or more sialic acids and a ceramide chain. The analysis of the glycan moieties among different subclass gangliosides, including GM, GD, and GT gangliosides, remains a challenge for shotgun lipidomics. Here, we present a novel shotgun lipidomics approach employing gas-phase ion/ion chemistry. The gas-phase derivatization strategy provides a rapid way to manipulate the ion-types of the precursor ions, and, in conjunction with collision induced dissociation (CID), allows for the elucidation of the structures of the glycan moieties from gangliosides. In addition to the enhancement of structural characterization, gas-phase ion chemistry leads to a form of purification of the precursor ions prior to CID by neutralizing isobaric or isomeric ions with different charge states but with similar or identical m/z values. To demonstrate the proposed strategy, both deprotonated GM3 and GM1 gangliosides ([GM-H]-) were isolated and subjected to reaction with magnesium-Terpy complex cations ([Mg(Terpy)2]2+). The post-reaction product spectra show the elimination of possible contamination, illustrating the ability of charge-switching derivatization to purify the precursor ions. Isomeric differentiation between GD1a and GD1b was achieved by the sequential ion/ion reactions, with the CID of [GD1-H+Mg]+ showing diagnostic fragment ions from the isomers. Moreover, isomeric identification among GT1a, GT1b, and GT1c was accomplished while performing a gas-phase magnesium transfer reaction and CID. Lastly, the presented workflow was applied to ganglioside profiling in a porcine brain extract. In total, 34 gangliosides were profiled among only 20 precursor ion m/z values by resolving isomers. Furthermore, the fucosylation site on GM1 and GD1, and N-glycolylneuraminic acid conjugated GT1 isomers was identified. Relative quantification of isomeric two isomeric pairs, GD1a/b C36:1 and GD1a/b C38:1 was also achieved using pure component product ion spectra coupled with a total least-squares method. The results demonstrate the applicability and strength of using shotgun MS coupled with gas-phase ion/ion chemistry to characterize the glycan moiety structures on different subclasses of gangliosides.

The synthetic unnatural amino acids and their peptides as peptidomimetics have shown remarkable structural and functional properties. In the repertoire of synthetic peptides, pseudopeptides have emerged as attractive small peptidomimetics that are capable of forming the characteristic secondary structures in the solid/solution phase, as in natural peptides. This report describes the synthesis and structural analyses of novel pseudopeptides as ethylenediprolyl (etpro) tetra/hexapeptides, comprising a chiral diaminedicarboxylate scaffold. Their NMR and CD spectral analyses strongly support the formation of the β-turn-type structures in organic solvents (ACN/MeOH). Further, the single-crystal X-ray studies of tetrapseudopeptide confirm the formation of a unique self-assembly structure as β-strand type in the solid state through hydrogen bonding. Importantly, their diamine moiety influences the formation of Cu-complexes with Cu(II) ions. A tetrapseudopeptide monocarboxylate-Cu(II) complex forms the single crystal that is studied by the single-crystal X-ray diffractometer. The crystal structure of the tetrapseudopeptide-Cu(II) complex confirms the formation of the distorted square planar geometry structure, almost like the amyloid β(Aβ)-peptide-Cu(II) complex structural geometry. Hence, these etpro-pseudopeptides are emerging peptidomimatics that form β-turn types of structures and metal complexes mainly with Cu(II) ions. These molecules could be considered for the development of peptide-based catalysts and peptide-based therapeutic drug candidates.

Cyclopropane rings are an important structural motif frequently found in many natural products and pharmaceuticals. Commonly, biocatalytic methodologies for the asymmetric synthesis of cyclopropanes rely on repurposed or artificial heme enzymes. Here, we engineered an unusual cofactor‐independent cyclopropanation enzyme based on a promiscuous tautomerase for the enantioselective synthesis of various cyclopropanes via the nucleophilic addition of diethyl 2‐chloromalonate to α,β‐unsaturated aldehydes. The engineered enzyme promotes formation of the two new carbon‐carbon bonds with excellent stereocontrol over both stereocenters, affording the desired cyclopropanes with high diastereo‐ and enantiopurity (d.r. up to 25:1; e.r. up to 99:1). Our results highlight the usefulness of promiscuous enzymes for expanding the biocatalytic repertoire for non‐natural reactions., Engineering of a promiscuous 4‐oxalocrotonate tautomerase (4‐OT) resulted in an unusual cofactor‐independent cyclopropanation enzyme that promotes the stereoselective addition of diethyl 2‐chloromalonate to substituted cinnamaldehydes to afford various cyclopropanes with high diastereo‐ and enantiopurity.

1,2-β-Mannobiose phosphorylases (1,2-β-MBPs) from glycoside hydrolase 130 (GH130) family are important bio-catalysts in glycochemistry applications owing to their ability in synthesizing oligomannans. Here, we report the crystal structure of a thermostable 1,2-β-MBP from Thermoanaerobacter sp. X-514 termed Teth514_1789 to reveal the molecular basis of its higher thermostability and mechanism of action. We also solved the enzyme complexes of mannose, mannose-1-phosphate (M1P) and 1,4-β-mannobiose to manifest the enzyme-substrate interaction networks of three main subsites. Notably, a Zn ion that should be derived from crystallization buffer was found in the active site and coordinates the phosphate moiety of M1P. Nonetheless, this Zn-coordination should reflect an inhibitory status as supplementing Zn severely impairs the enzyme activity. These results indicate that the effects of metal ions should be taken into consideration when applying Teth514_1789 and other related enzymes. Based on the structure, a reliable model of Teth514_1788 that shares 61.7% sequence identity to Teth514_1789 but displays a different substrate preference was built. Analyzing the structural features of these two closely related enzymes, we hypothesized that the length of a loop fragment that covers the entrance of the catalytic center might regulate the substrate selectivity. In conclusion, these information provide in-depth understanding of GH130 1,2-β-MBPs and should serve as an important guidance for enzyme engineering for further applications.

Pressure solution of carbonate-based rocks participates in many geophysical and geochemical processes, but fundamental knowledge of the interfacial processes is still lacking. By concurrently pressing and sliding two single calcite crystals past each other, the pressure solution rate and the friction force between the crystals were concurrently measured in calcium-carbonate saturated water with an extended surface forces apparatus. These studies reveal that both a decrease and an increase in frictional strength can originate from the pressure-solution of calcite single crystals. By conducting nanoscale force measurements with an atomic force microscope, ion specific effects were unveiled at the level of a single asperity. Pressure solution is promoted when the interfacial water layers of calcite remain undisturbed under stress (e.g. with Ca(II)) and the dissolved ions and water lubricate the interface – a phenomenon called pressure-solution facilitated slip. The mechanically induced disruption of the hydration layers of the calcite surface (e.g. with Mg(II) and low Ni(II) concentration) correlates with the more fluid-like and lubricious behavior of the confined fluid in the absence of pressure solution. Charge neutralization of the calcite surface leads to an abrupt change of calcite’s hydration layers, which promotes pressure-solution facilitated slip. This work advances the fundamental understanding of physicochemical interactions occurring at confined surfaces of stressed calcite.

Adenosine triphosphate (ATP) acts as the main energy source for growth and development in organisms, and the disorder reflects the mitochondrial damage to a large extent. Therefore, an efficient tool for the evaluation of the ATP metabolic level is important to track mitochondrial health, providing an additional perspective for an in-depth long-term study on living activities. Herein, a twisted intramolecular charge transfer (TICT) framework is utilized to build up a sensitive receptor, Mito-VP, with a negligible background to target mitochondrial ATP metabolism by monitoring the phosphate ion (Pi) level upon ATP hydrolysis under the overall consideration of the structural and functional features of mitochondria. The responsive fluorescence could be lighted on under the dual control of Pi and local microviscosity, and the two steps of ATP hydrolysis could be captured through fluorescence. In addition to the well-behaved mitochondrial targeting, the energy metabolism at cellular and organism levels has been clarified via mitosis and zebrafish development, respectively.

Classical application of ion-selective membranes is limited to either electrochemical or optical experiments. Herein, the proposed ion-selective membrane system can be used in both modes; each of them offering competitive analytical parameters: high selectivity and linear dependence of the signal on logarithm of analyte concentration, high potential stability in potentiometric mode, or applicability for alkaline solutions in optical mode. Incorporation of analyte ions into the membrane results in potentiometric signals, as in a classical system. However, due to the presence of lipophilic positively charged ions, polymer backbones, full saturation of the membrane is prevented even for long contact time with solution. The presence of both positively charged and neutral forms of conducting polymers in the membrane results in high stability of potential readings in time. Optical signal generation is based on polythiophene particulates dispersed within the ion-selective membrane as the optical transducer. An increase of emission is observed with an increase of analyte contents in the sample.

CRISPR-associated protein 1 (Cas1) is a universally conserved essential metalloenzyme of the clustered regularly interspaced short palindromic repeat (CRISPR) immune system of prokaryotes (bacteria, archaea) that can cut and integrate a part of viral DNA to its host genome with the help of other proteins. The integrated DNA acts as a memory of viral infection, which can be transcribed to RNA and stop future infection by recognition (based on the RNA/DNA complementarity principle) followed by protein-mediated degradation of the viral DNA. It has been proposed that the presence of a single manganese (Mn2+) ion in a conserved divalent-metal-ion binding pocket (key residues: E190, H254, D265, D268) of Cas1 is crucial for its function. Cas1-mediated DNA degradation was proposed to be hindered by metal substitution, metal chelation, or mutation of the binding pocket residues. Cas1 is active toward dsDNA degradation with both Mn2+ and Mg2+. X-ray structures of Cas1 revealed an intricate atomic interaction network of the divalent-metal-ion binding pocket and opened up the possibility of modeling related metal ions (viz., Mg2+, Ca2+) in the binding pocket of wild-type (WT) and mutated Cas1 proteins for computational analysis, which includes (1) quantitative estimation of the energetics of the divalent-metal-ion preference and (2) exploring the structural and dynamical aspects of the protein in response to divalent-metal-ion substitution or amino acid mutation. Using the X-ray structure of the Cas1 protein from Pseudomonas aeruginosa as a template (PDB 3GOD), we performed (∼2.23 μs) classical molecular dynamics (MD) simulations to compare structural and dynamical differences between Mg2+- and Ca2+-bound binding pockets of wild-type (WT) and mutant (E190A, H254A, D265A, D268A) Cas1. Furthermore, reduced binding pocket models were generated from X-ray and molecular dynamics (MD) trajectories, and the resulting structures were subjected to quantum chemical calculations. Results suggest that Cas1 prefers Mg2+ binding relative to Ca2+ and the preference is the strongest for WT and the weakest for the D268A mutant. Quantum chemical calculations indicate that Mn2+ is the most preferred relative to both Mg2+ and Ca2+ in the wild-type and mutant Cas1. Substitution of Mg2+ by Ca2+ does not alter the interaction network between Cas1 and the divalent metal ion but increases the wetness of the binding pocket by introducing a single water molecule in the first coordination shell of the latter. The strength of metal-ion preference (Mg2+ versus Ca2+) seems to be dependent on the solvent accessibility of the divalent-metal-ion binding pocket, strongest for wild-type Cas1 (in which the metal-ion binding pocket is dry, which includes two water molecules) and the weakest for the D268A mutant (in which the metal-ion binding pocket is wet, which includes four water molecules).

BACKGROUND: To prevent unsolved problems of medical devices, we hypothesized that combinatorial effects of zwitterionic functional group and anti-bacterial metal ions can reduce effectively the thrombosis and bacterial infection of polymeric biomaterials. In this research, we designed a novel series of zwitterionic polyurethane (zPU) additives to impart anti-thrombotic properties to a polyvinyl chloride (PVC) matrix. METHODS: We have synthesized zPUs by combination of various components and zPUs complexed with metal ions. Zwitterion group was prepared by reaction with 1,3-propane sultone and Nmethyldiethanolamine and metal ions were incorporated into sulfobetaine chains via molecular complexation. These zPU additives were characterized using FT-IR, 1H-NMR, elemental analysis, and thermal analysis. The PVC film blended with zPU additives were prepared by utilizing a solvent casting and hot melting process. RESULTS: Water contact angle demonstrated that the introduction of zwitterion group has improved hydrophilicity of polyurethanes dramatically. Protein adsorption test resulted in improved anti-fouling effects dependent on additive concentration and decreases in their effects by metal complexation. Platelet adhesion test revealed anti-fouling effects by additive blending but not significant as compared to protein resistance results. CONCLUSION: With further studies, the synthesized zPUs and zPUs complexed with metal ions are expected to be used as good biomaterials in biomedical fields. Based on our results, we can carefully estimate that the enhanced anti-fouling effect contributed to reduced platelet adhesion. GRAPHIC ABSTRACT: Schematic explanation of the effect of zwitterionic polyurethane additives for blood-compatible and anti-bacterial bulk modification. [Image: see text]

New methods are needed for global lipid profiling due to the complex chemical structures and diverse physicochemical properties of lipids. Herein we introduce a robust data workflow to unambiguously select lipid features from serum ether extracts by multisegment injection-nonaqueous capillary electrophoresis-mass spectrometry (MSI-NACE-MS). An iterative three-stage screening strategy is developed for nontargeted lipid analyses when using multiplexed electrophoretic separations coupled to an Orbitrap mass analyzer under negative ion mode. This approach enables the credentialing of 270 serum lipid features annotated based on their accurate mass and relative migration time, including 128 ionic lipids reliably measured (median CV ≈ 13%) in most serum samples (>75%) from nonalcoholic steatohepatitis (NASH) patients (n = 85). A mobility map is introduced to classify charged lipid classes over a wide polarity range with selectivity complementary to chromatographic separations, including lysophosphatidic acids, phosphatidylcholines, phosphatidylinositols, phosphatidylethanolamines, and nonesterified fatty acids (NEFAs). Serum lipidome profiles were also used to differentiate high- from low-risk NASH patients using a k-means clustering algorithm, where elevated circulating NEFAs (e.g., palmitic acid) were associated with increased glucose intolerance, more severe liver fibrosis, and greater disease burden. MSI-NACE-MS greatly expands the metabolome coverage of conventional aqueous-based CE-MS protocols and is a promising platform for large-scale lipidomic studies.

In this study, silver nanoclusters as prooxidant biosensor were eco-friendly synthesized using chicken egg white protein without any chemical reducing agents for measuring copper(II)-induced prooxidant activities of catechin, epicatechin, epigallocatechin gallate, resveratrol, gallic acid, chlorogenic acid, and rutin. The prooxidant activities were evaluated via measuring the absorption at 450 nm wavelength of the Cu(I)-neocuproine chelate formed by extraction of protein-bound Cu(I) with neocuproine reagent. Accuracy was determined by evaluating recovery values of wine, grape and apple samples and the obtained values were between 97.2%-98.9%. Intraday precision and inter-day reproducibility experiments were studied with three different experiments in a day and three different days respectively. The obtained relative standard deviation values were 0.96% and 1.91%. The detection limit of the biosensor was found as 0.2 mu M. The total prooxidant activities of fresh apple and grape fruits, apple and grape juices, and red wine were determined and the results obtained were compared with the findings of the carbonyl assay. In this study, a cheap, easily applicable, sensitive, and reproducible biosensor was developed. It was seen that it could be used in the measurement of the prooxidant activity of different food samples and give an idea about diet, healthy life, and nutrition.

Unclear impurity pollution is one of the key scientific problems that limit the large-scale production of new lithium-ion batteries (LIBs) from spent LIBs. This work is the first to report the pollution path, pollution degree, and solution method of sodium ions in the recycling process of spent LIBs in the real world. The results show that sodium ions can intrude into the precursor particles to form crystalline salts with the anion of the leaching acid that cover the transition metal elements, thereby resulting in a failed precursor. Specifically, the intrusion of sodium ions will produce a variety of pollutants containing metal oxide bonds, such as Na-O, NaO2, and Na+-O2, on the precursor surface. These active lattice oxygen will further adsorb or react to form organic oxygen, chemical oxygen, and free oxygen, which will highly deteriorate the surface cleanliness. Strictly controlling the consumption of sodium salt in each step and using ammonia instead of NaOH for pH regulation can effectively solve sodium ion pollution to prepare high-quality battery precursors. It reveals that for the green upcycling of spent LIBs, we should strengthen the design of the recycling process to reduce the consumption of chemical reagents, which will produce unexpected secondary pollution.

A cross-reactive sensor array is powerful for high-throughput discrimination of various kinds of metal ions. However, the construction of a multicomponent sensor array is always time-consuming and cost-ineffective. Herein, a practical four-component X1-based sensor array (X1SA) was obtained by simply dissolving a single dye molecule X1 in respective solvents such as methanol, ethanol, dimethyl sulfoxide, and acetonitrile. In this design, X1 exhibits strong solvatochromic fluorescence properties via an excited-state intramolecular proton transfer and intramolecular charge transfer combined mechanism. Moreover, rotation of the C-N bond between the pyridine and coumarin units in X1 enabled it to coordinate with metal ions through different binding modes, which acted as an additional dimension of the sensor array. Inspired by this C-N bond rotation strategy, X1SA was determined to be powerful in discriminating 20 kinds of metal ions in both phosphate-buffered saline and 5% serum media in a range of 0.1-100 μM. In addition, the sensor array was also successfully applied in differentiating similar and mixed metal ions such as Fe3+/Fe2+, Cd2+/Hg2+, and Sn2+/Pb2+ in serum samples, which is meaningful for investigating the biological roles of iron and early diagnosis of related metal poisoning accidents.

In this research, porous adsorbents of hypercrosslinked microporous polymer based on carbazole networks (HCP-CN) were synthesized for Pb(II) elimination from wastewaters. The results demonstrated that the extreme HCP-CN adsorbents utilization in wastewater treatment could remove more than 99.88% of Pb (II) ions. Furthermore, the two consumed adsorbents similarly indicated rapid adsorption kinetics, and it merely took a while to achieve adsorption equilibrium. These characteristics showed that HCP-CN adsorbent was an outstanding candidate for Pb(II) elimination from wastewater. Besides, the thermodynamic characteristics involving Gibbs free energy change (∆G0), entropy change (∆S0), and enthalpy change (∆H0) of the adsorption procedure were evaluated, and the results affirmed that the adsorption process was exothermic and spontaneous. In addition, response surface methodology (RSM) as a statistical investigation was used to optimize adsorption factors to obtain maximum adsorption capacity and investigate the interactive effect of parameters using central composite design (CCD). Optimum conditions obtained by RSM for maximum adsorption capacity of 26.02 mg/g are 35 °C, 40 mg/L, 11, 60 min, and 99.88 for temperature, initial concentration, pH, time, and removal percent, respectively. In the kinetic modeling study, the second-order model was selected as the best model. The values R2 at temperatures 35 °C, 40 °C, and 55 °C are 0.997, 0.9997, and 0.998, respectively. In the isotherm modeling, Hill model with a value R2 of 0.9766 has a superior precision compared to the other isotherm models. Also, the values of ΔH and ΔS at Pb(II) concentration of 60 mg/L are 122.622 kJ/mol and 0.463 kJ/mole K, respectively.

A simple and straightforward approach to the synthesis of trifluoromethyl and difluoromethyl ketones from widely available carboxylic acids is disclosed. The transformation utilizes an acyloxyphosphonium ion as the active electrophile, conveniently generated in situ from the carboxylic acid substrate by using commodity chemicals. The utility of the reaction system is exemplified by its chemoselectivity, with tolerance to a variety of important functional groups. The late-stage functionalization of carboxylic acid active pharmaceutical ingredients and pharmaceutically relevant compounds is also discussed.

The binding of group II metal cations such as Ca2+ and Mg2+ has been largely categorized as electrostatic or ionic using carboxylate symmetric and asymmetric stretching frequency assignments that have been historically used with little regard for the solvation environment of aqueous solutions. However, given the importance of these cations and their binding mechanisms related to biological function and in revealing surface enrichment factors for ocean to marine aerosol transfer, it is imperative that a deeper understanding be sought to include hydration effects. Here, infrared reflection-absorption and Raman spectra for surface and solution phase carboxylate binding information, respectively, are compared against bare (unbound) carboxylate and bidentate Zn2+:carboxylate spectral signatures. Spectral non-coincidence effect analysis, temperature studies, and spectral and potential of mean force calculations result in a concise interpretation of binding motifs that include the role of mediating water molecules, that is, contact and solvent-shared ion pairs. Calcium directly binds to the carboxylate group in contact ion pairs where magnesium rarely does. Moreover, we reveal the dominance of the solvent-shared ion pair of magnesium with carboxylate at the air-water interface and in solution.

Sesbania cannabina galactomannan (2%) solutions added with strongly hydrated ions (Na2CO3, NaH2PO4, NaCl) and weakly hydrated ions (NaNO3) at different ionic strengths were rheologically characterized. The four selected salts dramatically decreased the intrinsic viscosity of galactomannan solution in the following order of effectiveness: Na2CO3

A new adsorbent from chitosan and anionic silica was prepared by ionic interaction followed by sol-gel process. The obtained nanocomposite was characterized by different techniques: FTIR, XRD, SEM/EDX, TGA, and TEM. The results showed that silica precursor interacts with chitosan and deposits as regular spherical nanoparticles. The methylene blue (MB) adsorption by chitosan/silica nanocomposite achieved the adsorption equilibrium within 60 min. The adsorption method is fitted to the pseudo-second-order kinetic model and the Langmuir adsorption model with a maximum adsorption capacity of 847.5 mg/g at slight alkaline solution. Chitosan/silica composite displayed high regeneration capability and recovery of MB up to five cycles without the loss of the adsorption efficiency. The current study showed that as-prepared chitosan/silica nanocomposite is an appropriate material for the adsorption of organic pollutants from wastewater.

The recognition and sensing of various analytes in aqueous and biological systems by using fluorometric or colorimetric chemosensors possessing high selectivity and sensitivity, low cost has gained enormous attention. Furthermore, thiophene derivatives possess exceptional photophysical properties compared to other heterocycles, and therefore they can be employed in chemosensors for analyte detection. In this review, we have tried to explore the design and detection mechanism of various thiophene-based probes, practical applicability, and their advanced models (design guides), which could be thoughtful for the synthesis of new thiophene-based probes. This review provides an insight into the reported chemosensors (2008-2020) for thiophene scaffold as effective emission and absorption-based chemosensors.

Flexible aqueous battery is considered to be one of the most promising energy storage devices for powering flexible electronics. However, inferior interfacial compatibility in electrode–electrolyte interfaces and inefficient ionic channel of electrolytes usually result in potential troubles when applied in practical applications. Herein, we report a mild synthetic route to a sodium lignosulfonate-polyacrylamide hydrogel electrolyte with a high adhesiveness to achieve low electrode–electrolyte interfacial resistance and fast ionic conduction. Comprehensive experiments show that the catechol groups from sodium lignosulfonate demonstrate strong interactions with both cathode and anode materials, and thus greatly reduce the contact resistances across the electrodes. Meanwhile, the existence of sulfonate groups significantly enhances the ionic conductivity of the hydrogel electrolyte. Benefiting from this design, a low ohmic resistance of 3.8 Ω (i.e., 11.4 Ω cm2 ), a low charge transfer resistance of 22.5 Ω (i.e., 67.5 Ω cm2 ), a high ionic conductivity of 31.1 mS cm−1 as well as a 100% capacity retention upon harsh bending deformation can be realized in the flexible zinc ion battery, which are significantly superior to those in the traditional candidates. The present investigation provides new insight into addressing the interfacial issue plaguing flexible energy storage devices.

A causal relationship between plasma ceramide concentration and respiratory distress symptoms in COVID-19 patients is inferred. In this study, plasma samples of 52 individuals infected with COVID-19 were utilized in a lipidomic analysis. Lipids belonging to the ceramide class exhibited a 400-fold increase in total plasma concentration in infected patients. Further analysis led to the demonstration of concentration dependency for severe COVID-19 respiratory symptoms in a subclass of ceramides. The subclasses Cer(d18:0/24:1), Cer(d18:1/24:1), and Cer(d18:1/22:0) were shown to be increased by 48-, 40-, and 33-fold, respectively, in infected plasma samples and to 116-, 91- and 50-fold, respectively, in plasma samples with respiratory distress. Hence, monitoring plasma ceramide concentration, can be a valuable tool for measuring effects of therapies on COVID-19 respiratory distress patients.

A series of novel heteroditopic halogen bonding (XB) receptor functionalised silica based materials, containing mono‐ and bis‐iodotriazole benzo‐15‐crown‐5 groups are investigated for the cooperative binding and extraction of sodium halide ion‐pair species from aqueous solution. Characterisation of the XB materials by CHN elemental analysis, 13C CP/MAS NMR and ATR‐FTIR spectroscopies confirms and quantifies the successful incorporation of the ion‐pair receptor frameworks to the silica material. ICP‐MS solid‐liquid extraction studies demonstrate the bidentate XB functionalised material is capable of NaI extraction from water. Importantly, cooperative XB‐mediated sodium halide ion‐pair binding is determined to be crucial to the material's extraction capabilities, impressively demonstrating a two‐fold enhancement in sodium iodide extraction efficiency relative to a heteroditopic hydrogen bonding receptor functionalised silica material analogue., A series of halogen bonding (XB) heteroditopic ion‐pair receptors comprising of benzo15‐crown‐5 cation binding moieties and iodotriazole XB donors are covalently integrated into silica QuadraSilTM based solid supports. Investigations into their sodium halide extraction capabilities demonstrated their ability as NaI extraction agents from water. Comparison with HB analogues demonstrate the crucial role of XB‐mediated NaI ion‐pair binding in the extraction performance.

Currently, the world faces difficulties related to the quantity and quality of water because of industrial expansion, population growth, and urbanization intensification. Biosorption is considered a promising technology that can be applied to remove toxic metals (TMs) and rare-earth metals (REMs) in wastewater at low concentrations, due to its efficiency and low cost. In this work, we investigated different non-conventional biosorbents to remove metallic ions (TMs and REMs) in biosorptive affinity tests. Metallic affinity assays among lanthanum and different biosorbents showed that greater affinities were found for sericin-alginate beads crosslinked with polyvinyl alcohol (SAPVA) (0.280 mmol/g) and polyethylene glycol diglycidyl ether (SAPEG) (0.277 mmol/g), expanded vermiculite (0.281 mmol/g), Sargassum filipendula seaweed (0.287 mmol/g), and seaweed biomass waste (0.289 mmol/g). Among the biosorbents evaluated, SAPVA and SAPEG beads, besides to sericin-alginate beads crosslinked with proanthocyanidins (SAPAs) were selected for affinity assays with other REMs and TMs. Compared to other particles, SAPVA beads showed higher potential for biosorption by REMs with the following order of affinity: Yb3+ > Dy3+ > Nd3+ > Ce3+ > La3+. Additionally, the biosorptive affinity of TMs by SAPVA beads followed the order: Al3+ > Cr3+ > Pb2+ > Cu2+ > Cd2+ > Zn2+ > Ni2+.

Silver(I) ions undergo selective olefin complexation and have been utilized in various olefin/paraffin separation techniques such as argentation chromatography and facilitated transport membranes. Ionic liquids (ILs) are solvents known for their low vapor pressure, high thermal stability, low melting points, and ability to promote a favorable solvation environment for silver(I) ion-olefin interactions. To develop highly selective separation systems, a fundamental understanding of analyte partitioning to the stationary phase and the thermodynamic driving forces behind solvation is required. In this study, a chromatographic model treating silver(I) ions as a pseudophase is constructed and employed for the first time to investigate the olefin separation mechanism in silver(I) salt/IL mixtures. Stationary phases containing varying amounts of noncoordinated silver(I) salt ([Ag+][NTf2-]) dissolved in the 1-decyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C10MIM+][NTf2-]) IL are utilized to determine the partition coefficients of various analytes including alkanes, alkenes, alkynes, aromatics, aldehyde, esters, and ketones. As ligand coordination to silver(I) ions is known to lower its olefin complexation capability, this study also examines two different types of coordinated silver(I) ion pseudophases, namely, monocoordinated silver(I) salt ([Ag+(1-decyl-2-methylimidazole, DMIM)][NTf2-]) and dicoordinated silver(I) salt ([Ag+(1-methylimidazole, MIM)(DMIM)][NTf2-]). The extent of olefin partitioning to the coordinated silver(I) ion pseudophases over the carrier gas and IL decreased by up to two orders of magnitude. Values for enthalpy, entropy, and free energy of solvation were determined for the three silver(I) ion-containing systems. Olefin retention was observed to be enthalpically dominated, while ligand coordination to the silver(I) ion pseudophase resulted in variations for both enthalpic and entropic contributions to the free energy of solvation. The developed model can be used to study chemical changes that occur in silver(I) ions over time as well as identify optimal silver(I) salt/IL mixtures that yield high olefin selectivity.

The effects of Na-montmorillonite (Na-Mt) content and curing age on enzyme-induced carbonate precipitation (EICP)-treated soil were studied. First, the effects of Na-Mt addition on the urease activity, Ca2+ precipitation rate, and pH of the solution were analyzed through tube tests. Then, Na-Mt-modified EICP was used to reinforce silty sand in the Yellow River flooding area in China. The solidification effect and action mechanism of Na-Mt were investigated via the unconfined compressive strength (UCS) test, calcium carbonate content (CCC) measurement, X-ray diffraction, and scanning electron microscope analyses, wherein soil treated by conventional EICP and soil treated with Na-Mt alone were considered the control group. Na-Mt improved the urease activity and Ca2+ precipitation rate, lowered the pH, increased the CaCO3 production through chelation, then regulated the morphology of the CaCO3 crystals and facilitated the formation of densely aggregated calcite. The CCC and mechanical parameters increased rapidly during the first 7 days of curing, and then slowed down. The incorporation of 8% Na-Mt enhanced the UCS and Ca2+ utilization ratio at curing age of 7 days by 1.4 and 2.72 times, respectively, compared with that of traditional EICP; and the optimal Na-Mt content was identified to be 8%. At Na-Mt contents lower than 8%, the mathematically expressed improvement effect of the Na-Mt-modified EICP on the soil strength was greater than the arithmetic sum of that when these two approaches applied individually; this result confirms that the Na-Mt-modified EICP technique proposed herein is an efficient approach for solidifying fine-grained soil.

The [4Fe-4S] cluster containing scaffold complex HypCD is the central construction site for the assembly of the [Fe](CN)2CO cofactor precursor of [NiFe]-hydrogenase. While the importance of the HypCD complex is well established, not much is known about the mechanism by which the CN– and CO ligands are transferred and attached to the iron ion. We developed an efficient protocol for the production and isolation of the functional HypCD complex that facilitated detailed spectroscopic investigations. The results obtained by UV/Vis-, electron paramagnetic Resonance (EPR)-, Resonance Raman-, Fourier-transform infrared (FTIR), and Mössbauer spectroscopy provide comprehensive evidence for an electron inventory fit to drive multi-electron redox reactions. We demonstrate the redox activity of the HypCD complex reporting the interconversion of the [4Fe-4S]2+/+ couple. Additionally, we observed a reversible redox conversion between the [4Fe-4S]2+ and a [3Fe-4S]+ cluster. MicroScale thermophoresis indicated preferable binding between the HypCD complex and its interaction partner HypEF under reducing conditions. Together, these results suggest a redox cascade involving the [4Fe-4S] cluster and a conserved disulfide bond of HypD that may facilitate the synthesis of the [Fe](CN)2CO cofactor precursor on the HypCD scaffold complex.

Fingerprinting spectra of polymer materials containing information of monomers' molecular weight and detailed structure, constituents, and sequences were obtained by a direct analytical process using arc plasma-based dissociation (APD)-mass spectrometry. The thermal arc plasma generated using a simple arc discharge device induces the dissociation of the polymeric backbone, producing mass spectra with strong regularity within seconds. The molecular weight of the repeating unit was revealed by equal intervals between peak series and protonated monomer ions in the mass spectra. Meanwhile, lots of secondary fragment ions were produced to provide abundant structural information. For polyethers, it is even possible to decipher (read) the "sequence" directly from their spectra. Polymers composed of isomers or only differing in their initiator moieties were easily distinguished with their characteristic APD mass spectra. The spectra were highly reproducible according to the results of similarity calculation. Unlike pyrolysis mass spectrometry, in the APD device, polymers in liquid, solid, powder, and crude samples can be analyzed directly without any pretreatment, and the regular spectra are easier to interpret. Compared with other direct analytical methods, more structural informative spectra can be acquired owing to the high energy, high temperature, and unique chemical reactivity of arc plasma. Thus, this technique is promising to be a valuable tool in rapid elucidation of polymer materials.

Lignocellulose including cellulose, lignin, and hemicellulose could be extracted from wood, and has been used to prepare carbon electrode. However, complicated extraction greatly increases preparation cost. To achieve maximum utilization of lignocellulose and avoid complicated extraction, wood with porous structure and good mechanical strength is used as carbon precursor. Additionally, chemical activation is commonly used to create micropores to provide high capacitance, but it brings in natural structure destruction, and generation of wastewater during pickling. Moreover, to achieve desirable energy density, multi-step strategy with long duration is required for loading active materials on carbonized lignocellulose (CL). Herein, a one-step method is developed to prepare a free-standing hybrid CL electrode (CLE) by using Lewis acid in three aspects: (1) as structure protection agent, (2) as activating agent, (3) as active materials donor, which bypasses pickling and further avoids the generation of wastewater. Additionally, natural vessels in wood can not only provide large space for active materials loading, but also act as rapid ions diffusion way, simultaneously confining active materials detachment. Benefiting from the synergistic effect of porous structure and Lewis acid, this work not only makes full utilization of lignocellulose, but also makes CLE exhibit excellent performance in hybrid oxide supercapacitor.

Diels–Alder chemistry is a well-explored avenue for the synthesis of bioactive materials; however, its potential applications have recently expanded following the development of reactions that can be performed in buffered aqueous environments at low temperatures, including fulvene–maleimide [4 + 2] cycloadditions. In this study, we synthesized two novel amine-reactive fulvene linkers to demonstrate the application of this chemistry for generating mass spectrometry-cleavable labels (“mass tags”), which can be used for the labeling and detection of proteins. Successful conjugation of these linkers to maleimide-labeled peptides was observed at low temperatures in phosphate-buffered saline, allowing the non-destructive modification of proteins with such mass tags. The labile nature of fulvene–maleimide adducts in the gas phase also makes them suitable for both matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) mass spectrometric analysis. Unlike previous examples of MALDI mass tags, we show that fulvene–maleimide cycloaddition adducts fragment predictably upon gas-phase activation without the need for bulky photocleavable groups. Further exploration of this chemistry could therefore lead to new approaches for mass spectrometry-based bioassays. Refereed/Peer-reviewed

The design and preparation of multifunctional adsorbent for practical wastewater treatment is still an enormous challenge. To remove multiple metal ions from wastewater, we developed a broad-spectrum metal ions trap named UIO-67-EDTA by incorporation of ethylenediaminetetraacetic acid into robust UIO-67. The adsorption experiments for 15 kinds of heavy metal ions including hard acid (Mn2+, Ba2+, Al3+, Cr3+, Fe3+), borderline acid (Co2+, Ni2+, Cu2+, Zn2+, Pb2+, Sn2+, Bi2+), soft acid (Ag+, Cd2+, Hg2+), and two kinds of dissolved minerals (Mg2+, Ca2+) show that the trap is very effective both in batch adsorption processes and breakthrough processes. At a pH value of 4.0, the removal efficiency for all metal ions was over 98% within 10 min, and the maximum static adsorption capacity for the representative metal ions Cr3+, Hg2+and Pb2+ was up to 416.67, 256.41, and 312.15 mg g−1, respectively. The adsorption kinetics fitted well with the pseudo-second-order model, indicating that the chemical adsorption was the rate-determining step in the adsorption process. Meanwhile, the material showed high stability and recyclability, the removal efficiency for the three representative metals was still maintained over 93% after five consecutive adsorption cycles. HIGHLIGHTS Fabrication of a broad-spectrum heavy metal ion trap possessing strong chelating groups with high-density active binding sites; Serving as an extremely efficient adsorbent for multifarious and complex metal ions purification; High stability together with recyclability offering a potential possibility for practical applications.

Increased accumulation of heavy metal ions such as Cr6+ and Co2+ due to release from prostheses and metallic implants has been reported. These metal ions have been shown to affect both resting and activated lymphocytes. Natural remedies towards mitigating the cytotoxic effects of metal ions are clearly warranted. Polyphenolic compounds which are part of hydrolysable tannins from natural plant sources are considered effective in cheating heavy metal ions in a biological system. We have isolated and characterized a polyphenolic compound (ellagic acid) from Terminalia arjuna fruits that has been tested for its ability to attenuate the metal ion toxicity in primary human lymphocytes in culture. Cr6+ and Co2+ (100 μM) decreased lymphocyte viability and proliferation and increased apoptosis of resting as well as CD3 and/or CD28-stimulated lymphocytes. Metal ions markedly diminished the cytokine (interleukin-2 and interferon-γ) secretion from activated lymphocytes. Pretreatment with ellagic acid at 25, 50, and 100 μM concentrations effectively improved viability and proliferative responses of both resting and activated lymphocytes, while attenuating the apoptotic index. Ellagic acid also tended to normalize the cytokine secretion from the activated lymphocytes even in the presence of metal ions, suggesting broad effects on the adaptive immune system.

Due to its excellent chemical and mechanical properties, titanium has become the material of choice for orthopedic and dental implants to promote rehabilitation via bone anchorage and osseointegration. Titanium osseointegration is partially related to its capability to form a TiO2 surface layer and its ability to interact with key endogenous proteins immediately upon implantation, establishing the first bone-biomaterial interface. Surgical trauma caused by implantation results in the release of High Mobility Group Box 1 (HMGB1) protein, which is a prototypic DAMP (Damage Associated Molecular Pattern) with multiple roles in inflammation and tissue healing. To develop different surface strategies that improve the clinical outcome of titanium-based implants by controlling their biological activity, a molecular-scale understanding of HMGB1-surface interactions is desired. Here, we use molecular dynamics (MD) computer simulations to provide direct insight into the HMGB1 interactions and the possible molecular arrangements of HMGB1 on fully hydroxylated and non-hydroxylated rutile (110) TiO2 surfaces. The results establish that HMGB1 is most likely to be adsorbed directly onto the surface regardless of surface hydroxylation, which is undesirable because it could affect its biological activity by causing structural changes to the protein. The hydroxylated TiO2 surface shows a greater affinity for HMGB1 than the non-hydroxylated surface. The water layer on the non-hydroxylated TiO2 surface prevents ions and the protein from directly contacting the surface. However, it was observed that if the ionic strength increases, the total number of ions adsorbed on the two surfaces increases, and the protein’s direct adsorption ability decreases. These findings will help to understand the HMGB1-TiO2 interactions upon implantation, as well as the development of different surface strategies by introducing ions or ionic materials to the titanium implant surface to modulate its interactions with HMGB1 to preserve biological function.