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SARS-CoV-2 has high infectivity and some of its variants have higher transmissibility. To explore the high infectivity mechanism, the charge distributions of SARS-CoV, SARS-CoV-2, and variants of concern were calculated through a series of net charge calculation formulas. The results showed that the SARS-CoV-2 spike protein had more positive charges than that of SARS-CoV. Further results showed that the variants had similar but higher positive charges than preexisting SARS-CoV-2. In particular, the Delta variant had the greatest increase in positive charges in S1 resulting in the highest infectivity. In particular, the S1 positive charge increased greatly in the Delta variant. The S1 positive charge increased, and due to the large negative charge of angiotensin-converting enzyme-2 (ACE2), this resulted in a large increase in Coulomb’s force between S1 and ACE2. This finding agrees with the expectation that the positive charges in the spike protein result in more negative charges on SARS-CoV-2 antibodies than that of SARS-CoV. Thus, the infectivity of a novel SARS-CoV-2 variant may be evaluated preliminarily by calculating the charge distribution.

The two-electron reduction of the dismutational isomer of a 1,4-digermatetrasilabenzene cleaves one of the aryl groups in ligato-position and thus yields an unsaturated anionic Ge2Si4 cluster (digermatetrasila-benzpolarenide) with the negative charge at a Ge center. The regioselective positioning of the germanium centers in one nudo- and one ligato-position provides insight into the rearrangement of the Si4E2-scaffold of the dismutational isomers of hexatetrelbenzenes under reductive conditions with concomitant aryl group cleavage (E = Si and Ge).

Mining activity may potentially produce acid mine drainage (AMD), which has relatively high acidity and dissolved heavy metal concentrations. Constructed wetlands is one of the AMD management methods in which organic matter (OM) plays a very important function in reducing the concentration of heavy metals in AMD through absorption and precipitation processes. Three types of OM (empty fruit bunches of oil palm, chicken manure and water hyacinth) and five levels of OM (0, 10, 20, 30 and 40 Mg ha - 1 ) were applied to reclaimed-mining soils (RMS) in an incubation study. A batch experiment was then performed to measure the effect of OM application on the maximum sorption capacity ( Q max ) of iron (Fe) from the AMD onto the mixed soil - OM. The application of OM resulted in increases in soil pH, carboxylic groups, and total functional groups, in which these increases varied based on the types and amounts of OM application. This study also revealed that OM application resulted in increasing Fe sorption. The application of OM increased Q max values from 2077 to 2348 - 3259 mg kg - 1 (water hyacinth), to 2607 - 3635 mg kg - 1 (chicken manure), and to 2219 - 2992 mg kg - 1 (empty fruit bunches of oil palm). Increasing these Q max values may ascribe to increasing functional groups of the RMS with OM application. The results prove the importance of OM in controlling the sorption of Fe from AMD onto soils.

A mild condition via PPh3/I2/imidazole for the deoxygenation of substituted methanol derivatives has been identified. This metal-free process was found to proceed well on secondary or tertiary alcohols substituted with one or two heteroaryl groups, and it tolerates acid-sensitive heterocycles. This condition works for methanol derivatives substituted with 2-pyridyl, 4-pyridyl, or other heterocyclic groups, allowing the negative charge formed during the reaction to resonate to a nitrogen atom. Methanol derivatives substituted with 3-pyridyl or heterocyclic groups that do not allow the negative charge formed during the reaction to resonate to a nitrogen atom will not undergo deoxygenation under this condition.

New βββ-alanine modified tricarbocyanines containing various substituents at quaternized nitrogen atoms were obtained. The peptide synthesis method has been utilized for further conjugation thus giving promising tricarbocyanines containing two sulfonate groups and total negative charge of the fluorophore.

Wastewater treatment plants are suspected to be significant point sources of microplastic and nanoplastic particles (NPs) in the environment. As one of the main wastewater treatment processes, advanced oxidation processes (AOPs) may change the physicochemical properties of NPs and further affect their migration. However, limited information is known about the environmental fate of NPs after AOP treatment. In this study, polystyrene nanoparticles were treated using two representative AOPs, Fenton and persulfate treatments, and the migration of the NPs in quartz sand was investigated via column transport experiments. FTIR and XPS analysis indicated that a large number of oxygen-containing groups were generated on the NP surface after AOP treatment leading to lower hydrophobicity and a higher negative charge. Besides, the C/O ratio after Fenton and persulfate treatments was increased from 10.98 to 7.25 and 8.68. Moreover, the NPs after AOP treatment exhibited higher mobility in quartz sand in both ultrapure water and 10 mM NaCl solution. It was more obvious in 10 mM NaCl solution with breakthrough percentages of 79.73% for P-PS, 90.97% for F-PS and 95.67% for N-PS, respectively. These results could be explained by the roles of generated oxygen-containing functional groups; first, the higher negative charge enhanced the electrostatic repulsion between treated NPs and sand; second, lower hydrophobicity improved the binding with water molecules in background solution. This work is helpful in understanding the changes of nanoplastics in AOP treatment and their migration in the natural environment, which has far-reaching influence on the environmental fate and behavior of nanoplastics.

The parameters of a low-pressure glow discharge in neon with solid microparticles are experimentally and numerically studied in order to determine the region of the existence of charged dust clouds that most strongly affect the electrophysical parameters of a gas-discharge plasma in neon. It is shown that dust clouds with the maximum total negative charge are formed at the average electron density of 108 cm–3 over the volume of the discharge. The obtained values of the plasma parameters with dust clouds are close to the values characteristic of the disturbed states of the ionosphere.

Changes in the electrical properties of blood corpuscles that are experiencing mechanical stress modeled in vitro have been studied. An increase in the concentration of ATP molecules in the intercellular space in response to the mechanical effect of moving plasma layers both in the blood of healthy people and patients with acute lymphoblastic leukemia is demonstrated. The surface potential of red blood cells and platelets becomes more positive both in the blood of healthy people and in leukemia patients. In contrast, the negative charge of lymphocytes in healthy people decreases in response to mechanical stress but increases in the blood of patients with acute lymphoblastic leukemia.

Al-MCM 41 is an important material for reducing methylene blue waste through adsorption technique. The MCM 41 adsorption was mostly influenced on the MCM 41 framework that was built. Hence, the alumina incorporated on the MCM 41 will change the MCM 41 frameworks to become negative charge so that it influences the adsorption process of methylene blue. In this study evaluated the effect of alumina on MCM 41 frameworks in the adsorption process of the methylene blue. The research resulted that Al-MCM 41 has been synthesized directly, it showed any different on MCM framework because alumina caused the isomorphic substitution with Si atom. This indication can be identified from the shift of FTIR wavenumbers at 795 cm-1 that showed any different vibration of Si-O-Si and Si-O-Al, while the decreasing intensity of XRD indicated any different crystalinity formed. Al-MCM 41 has a good ability as an adsorbent for removing methylene and it is more effective than Si-MCM 41. Al-MCM 41 follows the adsorption model appropriate the Langmuir isotherm equation.

Light-induced cell harvest shows much potential in in vitro cell culture. In this work, a light-responsive monolayer graphene (Gr)/titanium dioxide nanodot (TN) film is designed and used for light-induced cell harvest. It is found that after 20 min of 365 nm UV or 450 nm visible light illumination, different types of cells could be detached from the surface effectively. The highest cell detachment ratio reaches about 95%. The mechanism of such a cell detachment is contributed to light illumination generates charge accumulation, which, in turn, changes the conformation of the extracellular matrix protein molecules adsorbed to a more disordered state, and eventually leads to the cells detachment. Such UV and visible light responsive Gr/TiO2 film could be a good candidate for a surface with light-induced cell detachment property.

Physicochemical aspects of the formation of solutions of nanosized C60 and some other fullerenes in aqueous media have been examined. The variety of methods for the preparation of aqueous dispersions of fullerenes gives rise sometimes to substantial differences in their colloidal, spectral, and other properties, including the chemical nature of impurities, bioactivity, and toxicity. Current methods for the quantitative analysis of fullerenes in aqueous media were summarized and attempts to standardize fullerene hydrosols were analyzed. The aggregative stability, coagulation, as well as the stabilization of hydrosols and suspensions of fullerenes were also reviewed. A new hypothesis for the structure of colloidal particles accounting for their negative charge was examined.

The correlations of the 1H NMR, 13C NMR and FT-IR spectral data from the R–O–CO groups in the alkyl carbamates and esters of homologous alcohols reveal R-group-dependent negative charge stabilization at the carbonyl oxygen and their donation to generic acceptors at Cα of even alkyl alcohols (R), which explains several of their apparently anomalous properties.

In this study, the construction of a highly negatively charged layered material [CH3CH2NH3]6In6S12 (InS-1) by introducing a lacunary cluster as the building block is reported. The pronounced framework negative charge density (5.59 × 10−3) and the soft Lewis basic S component endow InS-1 with an effective ion exchange performance toward heavier Sr2+, with a top-level adsorption capacity qm of 105.35 mg g−1. InS-1 exhibits a good exchange activity over pH 3–12, and the Sr2+-laden product can be facilely eluted.

Incorporation of a five-membered ring into a helicene framework disrupts aromatic conjugation and provides a site for selective deprotonation. The deprotonation creates an anionic cyclopentadienyl unit, switches on conjugation, leads to a >200 nm red-shift in the absorbance spectrum and injects a charge into a helical conjugated π-system without injecting a spin. Structural consequences of deprotonation were revealed via analysis of a monoanionic helicene co-crystallized with {K+ (18-crown-6)(THF)} and {Cs+2 (18-crown-6)3 }. UV/Vis-monitoring of these systems shows a time-dependent formation of mono- and dianionic species, and the latter was isolated and crystallographically characterized. The ability of the twisted helicene frame to delocalize the negative charge was probed as a perturbation of aromaticity using NICS scans. Relief of strain, avoidance of antiaromaticity, and increase in charge delocalization assist in the additional dehydrogenative ring closures that yield a new planarized decacyclic dianion.

In this work, for the first time it is demonstrated that supported single Au in either a positive or a negative charge state can catalyze acetylene hydrochlorination competitively with regard to ot...

Macrolides are widely used antibiotics with ubiquitous occurrence in aquatic environments. Unlike many emerging contaminants, macrolides are positively charged on their amine groups and are likely to interact with negative charge groups of dissolved organic matters (DOMs), which may alter macrolide bioaccumulation but yet to be explored. Here we evaluated the effects of different DOM (LeHA, PPHA, SRHA and SRFA) on erythromycin (an important macrolide) bioaccumulation into aquatic biota with 14C tracing. Results showed that ERY uptake in organisms was significantly inhibited by DOM (P, This study was funded by the National Key Research and Development Plan, China, (2016YFD0800207 & 2018YFD0200101) and the National Science Foundation of China (21577120).

In this study, seaweed polysaccharides (alginate and carrageenan) were modified with dodecenylsuccinic anhydride (DSA), and their stabilising properties in oil‐in‐water (O/W) emulsion system were evaluated. The physicochemical characteristics were determined by droplet size, interfacial tension and ζ‐potential and structurally verified by Fourier transform infrared spectroscopy (FTIR). Both CRG‐DSA and ALG‐DSA applied in O/W emulsion system exhibited smaller droplet sizes over the increasing concentration and were more stable during storage than native ones. The ζ‐potential of DSA‐modified seaweed polysaccharides has more negative charge compared with their native forms, owing to the additional carboxyl groups from modification reaction. In addition, DSA‐modified seaweed polysaccharides decreased the interfacial tension at soybean oil–water interface from 23.1 and 23.9 mN m⁻¹ to 14.2 and 13.6 mN m⁻¹, respectively. The successful modification reaction was confirmed by FTIR analysis. This study demonstrated that DSA‐modified seaweed polysaccharides may serve as prospective emulsifiers in food, pharmaceutical and other industrial fields.

The surface potential of anodic alumina films and their charge properties have been studied. The surface potential of anodic alumina films after anodic process has positive values, but then this potential is decreased to zero level with subsequent transition to negative values. The negative displacement of the surface potential is associated with a negative built-in electric charge of aluminum anodic oxide. The mechanism of transition from the positive built-in electric charge to the negative one inside the anodic oxides is proposed. The highest density of the negative charge is observed in the films formed in electrolytes based on the aqueous solutions of the citric and phosphoric acids.

Graphene oxide, an oxidized derivative of graphene, has many intriguing properties, such as amphiphilicity, negative charge, and easy mass production. However, due to the electronic insulation, graphene oxide cannot be directly used as a conductive agent for lithium batteries before reduction. Here we have demonstrated the enhanced rate and cycle capability of LiMn0.7Fe0.3PO4 with in situ electrochemically reduced graphene oxide by starting from discharge to 1.5 V vs. Li+/Li. For example, LiMn0.7Fe0.3PO4 with 2 wt% electrochemically reduced graphene oxide can obtain a high discharge capacity of ∼83 mAh g−1 at 30C and capacity retention of ∼90% at 1C after 200 cycles, much higher performance than that without graphene oxide (∼10 mAh g−1 and ∼56%, respectively). Moreover, the cathode with in situ electrochemically reduced graphene oxide also shows better performances than that with the externally reduced graphene oxide. The boosted performance is attributed to the effective conductive network formed by the well-dispersed graphene oxide.

International audience; Herein, we report the synthesis of an octavalent glycocluster exposing a thiodisaccharide mimetic of the repetitive unit of hyaluronic acid, βSGlcA(1 → 3)βSGlcNAc, constructed on a calix[4]resorcinarene scaffold by CuAAC reaction of suitable precursors. This glycocluster showed a strong tendency toward self-aggregation. DOSY-NMR and DLS experiments demonstrated the formation of spherical micelles of d ≅ 6.2 nm, in good agreement. TEM micrographs showed the presence of particles of different sizes, depending on the pH of the starting solution, thus evidencing that the negative charge on the micelle surface due to ionization of the GlcA residues plays an important role in the aggregation process. STD-NMR and DLS experiments provided evidence of the interaction between the synthetic glycocluster and Langerin, a relevant C-type lectin. This interaction was not observed in the STD-NMR experiments performed with the basic disaccharide, providing evidence of a multivalent effect.

A pasteurized liquid egg leads to protein denaturation and degradation of processing properties, whereas non-pasteurized eggs may have food safety risks. If the negative impact of the pasteurization process on liquid eggs can be reduced, for example, the loss of stability and foamability, companies will be willing to purchase pasteurized eggs, thereby reducing food safety risks. Therefore, in this study, specific hydrolyzation conditions were used to produce egg white hydrolysate (EWH) with a lower molecular mass of amino acid and peptide fragments, and the effects of various concentration of EWH refilling on pasteurized liquid egg properties were investigated. The results showed that up to 30.1% of EWH was hydrolyzed by protease A and papain. Adding 1% (w/w) EWH can improve the negative charge potential value, surface tension, viscosity, and weight loss analysis of the sample. In addition, the cake structure and the appearance was acceptable to consumers. Therefore, to ensure its efficient use in the baking industry and considering the cost and stability, 1% (w/w) EWH was chosen as the best concentration.

The methylglyoxal-derived hydroimidazolone isomer, MGH-1, is an abundant advanced glycation end-product (AGE) associated with disease and age-related disorders. As AGE formation occurs spontaneously and without an enzyme, it remains unknown why certain sites on distinct proteins become modified with specific AGEs. Here, we use a combinatorial peptide library to determine the chemical features that favor MGH-1. When properly positioned, tyrosine is found to play an active mechanistic role that facilitates MGH-1 formation. This work offers mechanistic insight connecting multiple AGEs, including MGH-1 and carboxyethylarginine (CEA), and reconciles the role of negative charge in influencing glycation outcomes. Further, this study provides clear evidence that glycation outcomes can be influenced through long- or medium-range cooperative interactions. This work demonstrates that these chemical features also predictably template selective glycation on full-length protein targets expressed in mammalian cells. This information is vital for developing methods that control glycation in living cells and will enable the study of glycation as a functional post-translational modification., Advanced glycation end-products (AGEs), such as methylglyoxal-derived hydroimidazolone isomer (MGH-1), are associated with disease and age-related disorders, and occur spontaneously, so it is unclear why specific protein sites become modified with specific AGEs. Here, the authors use a combinatorial peptide library to determine the chemical features that favour MGH-1 formation for short peptides and demonstrate a key role of tyrosine in this process.

Electrophoretic mobility shift assays (EMSAs) are amongst the most frequently used and straightforward experiments for studying protein-nucleic acid interactions. EMSAs rely on the principle that protein-nucleic acid complexes have reduced electrophoretic mobility in a native gel matrix compared to free nucleic acid due to their larger size and reduced negative charge. Therefore, bands for the protein-nucleic acid complexes are shifted in a gel and can be distinguished from free nucleic acids. EMSAs remain a popular technique since they do not require specialist equipment and the complexes formed are easily visualized. Furthermore, the technique can be adapted to enable various aspects of protein-nucleic acid interactions to be investigated, including sequence specificity, estimated binding affinity, and binding stoichiometry.

The way molecules break after ion bombardment is intimately related to the early electron dynamics generated in the system, in particular, charge (or electron) migration. We exploit the natural positive-negative charge splitting in the zwitterionic molecule betaine to selectively induce double electron removal from its negatively charged side by impact of fast O

With its innumerable features, carrageenan and its associated hydrogels are a group of promising candidates for various biomedical applications. The requirement of smart drug delivery platforms and solutions for various biomedical needs finds a great scope in these natural polysaccharides. Strong negative charge, unique gelling mechanism, the abundance of functional groups, and strong water absorption property make this seaweed-derived, natural, sulfated, linear polysaccharide a versatile candidate for sustained and controlled drug delivery applications. Carrageenan has extensive applications in the field of drug delivery as well as in the fields of tissue engineering and wound healing. The abundance of functional groups opens ample scope for chemical modification for the enhancement of the physicochemical properties of the hydrogel. In this chapter, we outline the diverse applications of carrageenan in the fields of tissue engineering, drug delivery, and wound healing. The recent progress made by carrageenan-based hydrogels highlighted in this chapter reaffirms the fact that carrageenan and related hydrogels are effective biomaterials for drug delivery, tissue engineering, and regenerative medicine.

The controlled formation of protein supramolecular assemblies is challenging but it could provide an important route for the development of hybrid biomaterials. In this work, we demonstrate formation of well-defined complexes formed between the 8-fold symmetrical designer protein Tako8 and soluble metal-oxo clusters from the family of Anderson-Evans, Keggin and ZrIV- substituted Wells-Dawson polyoxometalates. A combination of x-ray crystallography and solution studies showed that metal-oxo clusters are able to serve as linker nodes for the bottom-up creation of protein based supramolecular assemblies. Our findings indicate that clusters with larger size and negative charge are capable of modulating the crystal packing of the protein, highlighting the need for a size and shape complementarity with the protein node for optimal alteration of the crystalline self-assembly.

Liquid-like membraneless organelles form via multiple, weak interactions between biomolecules. The resulting condensed states constitute novel solvent environments inside eukaryotic cells that partition biomolecules and may favour particular biochemical reactions. Here we demonstrate that, in addition to attractive interactions, repulsive electrostatic interactions modulate condensate properties. We find that net charge modulates the formation, morphology and solvent properties of model Ddx4 condensates in cells and in vitro and that a net negative charge is conserved across germ cell-specific Ddx4 orthologues. This conserved net charge provides a sensitivity to multivalent cations that is not observed in somatic paralogues. The disfavouring effect of a net negative charge in Ddx4 orthologues appears to be offset by increased charge patterning, indicating that fine tuning of both attractive and repulsive interactions can create responsive solvent environments inside biomolecular condensates.

Self-assembly between symmetrical dicyclohexyl-substituted cucurbit[6]uril (abbreviated as (CyH)2Q[6]) and cyclopentanocucurbit[6]uril (CyP6Q[6]) as hosts and 1-(4-methoxyphenyl)piperazine (MeOPP) as a guest molecule has been studied by means of single-crystal X-ray diffraction analysis, NMR, MALDI-TOF mass spectrometry, and other characterization methods. The experimental results showed that the self-assembly was driven by the formation of exclusion complexes by the cucurbit[n]uril and the guest, that is, supramolecular interaction between the negative charge of the cucurbit[n]uril portals and a coordination polymer guest. Complexes were formed between the positive charge of the cucurbit[n]uril outer wall and inorganic anions, thus generating self-assemblies with multi-dimensional and multi-level supramolecular frameworks.

The use of nickel complexes utilizing non-innocent ligands based on picolinamide to function as redox carriers in flow batteries was explored. The picolinamide moiety was linked together with -CH2 CH2 - (bpen), -CH2 CH2 CH2 - (bppn), and -C6 H4 - (bpb) moieties, resulting in two, three, and four quasi-reversible waves, respectively, for the nickel complexes and >3 V difference between the outermost positive and negative waves. The redox events were theoretically modelled for each complex, showing excellent agreement (

The environmentally friendly electrokinetic process was investigated using model contaminated soil with Pb and humic acid. Although humic acid has a negative charge, it moved toward the cathode side by electroosmotic flow. The removal efficiency of Pb from model contaminated soil was 48.0% under 1 V/cm of the potential gradient after 72 h of operation, while it improved to 72.6% with humic acid. These results indicated that humic acid has high potential for application in the environmentally friendly remediation of soil.

Cationic frameworks are an emerging class of exceptional solid adsorbents capable of encapsulating highly toxic and persistent anionic pollutants. The controlled generation of cationic frameworks, however, lags behind the abundant design strategies devised to control the structures and topologies of neutral frameworks. In this regard, we report a rational approach that allows the conversion of the synthetic approach toward constructing a neutral framework into one allowing for the synthesis of a cationic one without incurring any changes to the overall topology or the selected metal ion. We demonstrate that the replacement of a functional group on an organic linker that promotes a similar coordination mode, but bearing one less negative charge, can yield the systematic generation of cationic frameworks. Moreover, we confirm the cationic nature of the metal-organic frameworks through preliminary anion-exchange experiments and propose a method to retain permanent porosity in cationic frameworks through the use of strongly binding anions. Altogether, these results show great promise for the construction of tunable nanoporous frameworks capable of carrying out anion-exchange processes.

Background. Previously, it was found that the drying of salt solutions prepared on water with a negative charge is accompanied by the arborization of salt crystals, i.e. – the formation of needle- or plant-shaped crystals. It was also found that low-frequency electromagnetic fields stimulate the regeneration of damaged neurons. Objective. The aim of the work was to test the hypothesis that negative electrization of the cytoplasm of neurons, as well as their axonal arborization, can occur under the influence of low-frequency electromagnetic fields. Methods. For the negative electrization of aqueous solutions of chlorides, various low-frequency (0 ÷ 100 Hz) EMF generators were used. Negative electrization of aqueous solutions of chlorides was visualized using the method of sensitive crystallization. Results. It is shown that under the action of low-frequency electromagnetic fields, arborization of chlorides, which are the main salt components of the cytoplasm of cells, including neurons, occurs. This made it possible to explain the nature of axonal arborization of damaged neurons, which is observed under the influence of low-frequency electromagnetic fields in vivo. Conclusion. Under the action of low-frequency electromagnetic fields, negative electrization of aqueous solutions of chlorides occurs. By preliminarily optimizing the content of chlorides in the body, it is possible to create optimal conditions for the axonal arborization of neurons and the formation of new capillaries using low-frequency electromagnetic fields.

It is assumed that the reason for the acceleration and amplification of the vibration and noise of ordinary tram tracks in recent years and decades is their high wear due to the lack of funds for their maintenance. However, the research of the authors of the article showed that the main reason for the gatherings and accidents is the excess negative charge of the Earth. The aim of the study is to reveal the mechanism of the protective properties of materials, in particular polyurethane and the liquid-glass composition (LGC), and their application to protect the tram tracks in conditions of high excess negative charge of the Earth. For this purpose, analytical and full-scale research methods are used, based on the principles and laws of Macrocolloid chemistry and Physico-chemical mechanics. For the construction of new tram tracks in big cities, huge reinforced concrete slab or monolithic bases combined with road ways are used. This led to an even greater accumulation of excess negative charge of the Earth under the combined tracks and houses, to the emergence of previously virtually absent ground dips under the tracks, to an increase in accidents with serious consequences. Polyurethanes recommended for use have not only higher vibration-damping properties, but also are protective against excessive negative charges of the Earth. The liquid-glass composition (LGC) has the same properties. These protective functions are due to active -С=О groups in polyurethane and -S=О groups in a liquid-glass composition. They have a double bond and high electronegativity, as well as very large dipole moments. Methods have been developed to protect materials and structures of the tram tracks and nearby houses from the excessive negative charge of the Earth with the help of protective screens and walls, as well as high-performance fastening SRS-T.

A series of Cu–SAPO-34 catalysts with different copper contents were prepared using a modified ion-exchange method, i.e., impregnation–activation. Controlled amounts of well-dispersed active copper species and integrated physical properties were obtained by this method. The Cu–SAPO-34 catalysts retained the CHA structure, high specific surface area, and pore volume of the H–SAPO-34. Based on a combined analysis of UV–vis spectra and H2-TPR, these common laboratory techniques enabled the identification of the different copper species present in the catalysts. Only isolated copper ions balanced by two framework charges were present in the catalysts at copper contents ≤ 0.8 wt%. With increasing the Cu content, isolated Cu2+ ions charge-balanced by one negative charge became dominant. Further higher Cu contents could result in formation of copper oxides after consumption of all ion-exchange sites.

Polyoxometalates (POMs), as early transition metal-oxo clusters of V, Mo, W, Nb, and Ta, have been attracting extensive interest owing to their structural variety associated with interesting structural characteristics such as high negative charge, oxygen-rich surface, and rich redox properties. In the past two centuries, the main success was achieved in POM chemistry of V, Mo, and W. In contrast, the advancement of polyoxotantalate (POTa) chemistry falls far behind that of POM chemistry of V, Mo, and W. The reasons lie in the narrow working pH region, the slight solubility, and the low reaction activity of tantalum species. Despite these hurdles, as an important subclass of POMs, POTas have received more and more intense interest and attentions because of their promising applications in photocatalysis and the base-catalyzed reactions. In recent years, considerable advancements in POTa chemistry have been made. During the past two decades, POM chemistry of polyoxovanadates, polyoxoniobates, polyoxomolybdates, and polyoxotungstates has been reviewed extensively. While, no review about POTas has been known to our knowledge. We are thus very interested in making a summary on the research advances of POTa chemistry with attempt to provide some insight into the syntheses of new POTa clusters, in particular brand-new and high-nuclearity POTas, which is a subject of current intense investigation. In this review, we systematically summarized the research progress in structural types, synthetic methods, and related applications of POTas, which were achieved in recent two decades. This review aims to be not only a snapshot of the recent developments of design, architecture, and application of POTas, but also to be employed as a guide to understand the different cluster types of POTas. The main content of the review includes the following four parts: (1) Isopolyoxotantalate species with different counter cations (Li, Na, K, Cs, and organic amines) and different aggregations (hexamer and decamer); (2) Tantalum-based polyoxometalates, including Ta-substituted polyoxotungstates derived from different structures such as Keggin-, Linqvist- and Dawson-type configurations; (3) Heteropolyoxotantalate species, including Ti- and P-containing POTas; and (4) Organic-inorganic hybrid polyoxotantalates constructed from lindqvist-type Ta6 decorated by various organic species (e.g., organometallic complexes and metal-organoamine complexes). According to the above four aspects, we not only summarized the different classifications of POTas but also their corresponding synthetic strategies. Especially, the synthetic methods of POTas has been summarized from the traditional hydrothermal method to a variety of synthetic strategies such as solvothermal, diffusion, and steam-heat. Further, on the issue of how to improve the aggregation degree of Ta atoms, we analyze the difficulties in constructing high-nuclearity POTas and the key factors affecting the construction of high-nuclearity POTas. Additionally, the review also represents that POTas have a variety of excellent properties and exciting application prospects in photocatalytic hydrogen production and degradation of organic pollutant. In summary, this review provides a personal view on the research in the area of POTa chemistry. From the review, it can be found that, even after more than decades of research, known POTas species are really very limited compared to POMs of V, Mo, W, and even Nb on the one hand. And on the other hand, alomost all known POTas are in the small nuclearity range ( 20). Obviously, the design and synthesis of POTas are of great challenge. Nevertheless, it is believed that the current state of POTas will continue to evolve, leading to a variety of expected and unexpected new species with fascinating structures and properties. It could be expected that the review may initiate more extensive research on the discovery of novel POTa materials and open up new perspectives for the development of POTa chemistry.

An insulator layer of ErF3, YF3, NdF3, and TmF3 was formed in n-type Ge-based MIS (metal–insulator–semiconductor) structures. It is shown that no negative effective charge is observed in these Ge MIS structures, while the degradation of electric characteristics and the rise of density of surface states leads to an increase in the positive charge. The positive charge formed at the Ge–rare-earth-element fluoride interface can compensate the negative charge of dangling bonds on the surface of Ge, which is potentially promising for modulation of the charge magnitude and sign in MIS devices based on Ge.

Radical anions of electrochemically reduced compounds (anolytes) have been suggested for storage of negative charge in nonaqueous redox flow batteries. The lower the redox potential of the anolyte molecule, the higher is the stored energy density. However, the stability of the radical ions frequently suffers as their redox potentials become extreme, and there is a compromise between the energy density and the chemical stability in the active form. In this study, we scrutinize this trade-off using one such “extreme,” the heterocyclic anolyte 2,1,3-benzothiadiazole, BzNSN, by adjusting the redox potential of BzNSN via installed electron-donating and electron-withdrawing groups. We show that the stability of the radical anion strongly depends on the degree of ion pairing in solution, with the worst being for the contact lithium ion pairs. For BzNSN derivatives, there is a strong correlation between the lifetime of the radical anion and the redox potential. The root cause appears to be the proton transfer fro...

Well-dispersed boron nitride nanosheets (BNNSs) reinforced fused silica composites were successfully fabricated by surface modification assisted flocculation method. Surface modification can enhance the performance of flocculation process. BNNSs were homogeneously mixed with fused silica through the electrostatic interaction between hydroxylated BNNSs with negative charge and amino-modified fused silica with positive charge. The BNNSs can act as excellent nanofillers for enhancing the mechanical properties of fused silica composites. Approximately 74% and 48% increases in flexure strength and fracture toughness can be achieved for the 1.5 wt% BNNSs/fused silica composite, respectively. The toughening mechanisms were analyzed by microstructural characterization, especially for pull-out mechanism.

Lipid oxidation often occurs during egg white protein (EWP) storage and processing periods. Here, 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH) was performed to simulate lipid oxidation to probe the oxidation effects on foaming and structural properties of EWP. Results indicated that EWP structure became unfolding and flexible after oxidation, resulting in more hydrophobic groups and negative charge exposed and soluble aggregates formed, which revealed by the results of DLS and AFM. Additionally, high resolution mass spectrometry results evidenced that ovotransferrin and lysozyme trended to be new oxidation targets with the AAPH concentration increasing, and the oxidation sites inside lysozyme proved that EWP unfolding and exposure of internal hydrophobic amino acids, which were related to the enhancement of EWP foaming properties. Overall, our study provided a further analysis of the lipid induced oxidation of EWP, which may contribute to provide a more accurate strategy for enhancing protein foaming properties in food industry.

A physical insight regarding poly(tetrafluoroethylene) (PTFE) is revealed herein. The driving force for the oriented growth of materials on aligned PTFE is investigated. The growth has been reported in numerous publications for a wide range of deposited materials on aligned PTFE layers since its discovery in 1991 because it is a promising method for preparing ordered molecular films. MD model simulations demonstrate herein that the shallow charged atomic grooves between adjacent PTFE chains trap typical two linear molecules, thus explaining the remarkable degrees of uniaxial orientation in their deposited thin films on the layers. Charge modifications to the model demonstrate for the first time that the negative charge of its fluorine atoms is crucial for the remarkable degrees. Hence, such an orientation is only possible with PTFE.

Two new oxyiodoplumbates, [Pb3O(μ3-OH)2I2]n (1) and [Pb4I4(μ4-L)2]n (2, H2L = ethylene glycol), have been solvothermally synthesized and structurally characterized. 1 consists of a 1-D tenioid [Pb3O(μ3-OH)2I2]n chain built up from 1-D tenioid [Pb2O(μ3-OH)2]n chains decorated [PbI2] groups, which provides a new type of oxyiodoplumbate, [Pb3O(μ3-OH)2I2]n, with oxhydryl groups. 2 consists of the rare neutral tetra-nuclear [Pb4L4] complexes and neutral 2-D [Pb2I4]n layers, which are interconnected to generate the only example of a 3-D hybrid oxyiodoplumbate based on neutral 2-D [Pb2I4]n layers, mainly because the reported iodoplumbate cores usually possess negative charge. The optical properties and density functional theory calculations of 1 and 2 were studied.

In order to understand the inhibitory mechanism of metabolic uncoupler in biofilm, this study investigated the effect of TCS on B. subtilis biofilm formation, flocculability, surface characteristics and thermodynamic properties. An optimal concentration of TCS, a metabolic uncoupler, was observed to substantially inhibit biofilm formation and the secretion of extracellular polymeric substances (EPS). The effect of TCS on the zeta potential and flocculability of bacterial suspension implied the addition of 100 μg L−1 TCS increased the net negative charge of cell surface which induced the reduction of B. subtilis flocculability. Meanwhile, the effects of TCS on bacterial surfacial thermodynamic properties were analyzed by the Derjaguin–Landau–Verwey–Overbeek (DLVO) and extend DLVO (XDLVO) theories. As DLVO and XDLVO predicted, the primary energy barrier between bacterial cells incubated with 100 μg L−1 TCS were increased compared to that of control, indicating that B. subtilis incubated with 100 μg L−1 TCS must consume more energy to aggregate or form biofilm.

The influence of the negative charge densities of metalate nanosheets on their bottom-up syntheses was examined. Metalate nanosheets are usually prepared by exfoliating layered metalates. For each metalate, the bottom-up synthesis yields only one type of nanosheet structure, although different layered structures are known. In this work, we compared the crystal structures of different layered metalates, and the results indicate that metalate nanosheets with the lowest negative charge density were formed for each metalate. Next, we examined the effect of the oxidation state of metal ions on the bottom-up synthesis of metalate nanosheets, because the negative charge density of the metalate sheets can be modified according to the oxidation state of the metal ion. For the bottom-up synthesis of manganate nanosheets, the lowest Mn oxidation state, which can be between 3 and 4, was as large as 3.65. Thus, their negative charge densities were relatively small. Additionally, cobaltate nanosheets could not be obtained via the bottom-up process; however, the oxidation of layered cobaltates led to the intercalation of bulky cations and water into the interlayer. These results suggest that low negative charge density is required for the bottom-up synthesis of metalate nanosheets.

The giant squid (Dosidicus gigas) has been proposed as raw material to obtain myofibrillar protein concentrates. However, it has been observed that colloidal systems formed from squid proteins have limited stability. Therefore, the isolation and characterization of the actomyosin-paramyosin isolated (API) complex were performed, because they are the main proteins to which functionality has been attributed.; Results: Densitogram analysis revealed 45% of actin, 38% of myosin and 17% of paramyosin. The amino acid profile indicates a higher proportion of acidic amino acids, which gives a higher negative charge; this was supported by the zeta potential. Total sulfhydryl (TSH) content was lower compared with proteins of other aquatic species.; Conclusion: The higher percentage of actin in relation to myosin, the presence of paramyosin, as well as the low content of sulfhydryl groups, could comprise the main causes of the low technological functional property of proteins from D. gigas mantle. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.

The effect of Na-montmorillonite (Mt) and synthetic stevensite (Ste) on the switchable properties of intercalated cationic cyanine dye, 1,1′-diethyl-2,2′-cyanine (pseudoisocyanine, PIC) was investigated. The switching between non-aggregated and J-type aggregated states of PIC was performed by adding and removing of dimethyl sulfoxide (DMSO) from the interlayer space. It was found that the photophysical properties of PIC after addition of DMSO are significantly influenced by the negative charge density of layered silicate. Due to this effect the J-type aggregates were after swelling with DMSO formed only in the PIC/Mt hybrid films. Photophysical response and the stability of PIC species in PIC/Mt hybrid film was tested within 20 cycles of adding and removing of DMSO from the interlayer space. During these cycles the stability of PIC species was proved to be sufficient, indicating that presented experimental approach is able to enhance the use and scope of materials consisting of J-type dye molecular assemblies.

In this work, the effect of the exfoliation degree of montmorillonite (MMT) platelets on their electrophoretic mobility distributions in aqueous suspensions was investigated in order to approach into the correlation of MMT exfoliation with electrokinetic property. The experimental results have shown that the negative mobility increased with the increase of exfoliation degree or with the decrease of MMT thickness. This observation might be attributed to the “exposing” of permanent layer negative charge during the exfoliation processing and the “spillover” of electrostatic potential from basal surfaces onto edges. The former would increase the permanent negative charge of the MMT platelets because of the large amounts of layer charge; the latter would decrease the positive edge charge. It is demonstrated that MMT exfoliation would change the electrokinetic property, which might be helpful of the applications of MMT in the related industries.