23,615 results match your criteria negatively charged

Factors governing microalgae harvesting efficiency by flocculation using cationic polymers.

Bioresour Technol 2021 Jul 27;340:125669. Epub 2021 Jul 27.

Center for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia. Electronic address:

This study aims to elucidate the mechanisms governing the harvesting efficiency of Chlorella vulgaris by flocculation using a cationic polymer. Flocculation efficiency increased as microalgae culture matured (i.e. Read More

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Interactions between the Cell Membrane Repair Protein S100A10 and Phospholipid Monolayers and Bilayers.

Langmuir 2021 Aug 2. Epub 2021 Aug 2.

Department of Ophthalmology, Faculty of Medicine, Université Laval, Quebec City, QC, G1S 4L8 Canada.

Protein S100A10 participates in different cellular mechanisms and has different functions, especially at the membrane. Among those, it forms a ternary complex with annexin A2 and the C-terminal of AHNAK and then joins the dysferlin membrane repair complex. Together, they act as a platform enabling membrane repair. Read More

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A Healable and Mechanically Enhanced Composite with Segregated Conductive Network Structure for High-Efficient Electromagnetic Interference Shielding.

Nanomicro Lett 2021 Aug 2;13(1):162. Epub 2021 Aug 2.

College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, People's Republic of China.

Highlights: The cationic waterborne polyurethanes microspheres with Diels-Alder bonds were synthesized for the first time. The electrostatic attraction not only endows the composite with segregated structure to gain high electromagnetic-interference shielding effectiveness, but also greatly enhances mechanical properties. Efficient healing property was realized under heating environment. Read More

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Calcium Ions Promote Membrane Fusion by Forming Negative-Curvature Inducing Clusters on Specific Anionic Lipids.

ACS Nano 2021 Aug 2. Epub 2021 Aug 2.

Institute of Chemistry, The Fritz Haber Center, and The Center for Nanoscience and Nanotechnology, The Hebrew University, E.J. Safra Campus, Jerusalem 9190401, Israel.

Vesicles enriched in certain negatively charged lipids, such as phosphatidylserine and PIP2, are known to undergo fusion in the presence of calcium ions without assistance from protein assemblies. Other lipids do not exhibit this propensity, even if they are negatively charged. Using our recently developed methodology, we extract elastic properties of a representative set of lipids. Read More

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Identification of beryllium fluoride complexes in mechanically distorted gels using quadrupolar split Be NMR spectra resolved with solution-state selective cross-polarization.

Phys Chem Chem Phys 2021 Aug 2. Epub 2021 Aug 2.

School of Life and Environmental Sciences, University of Sydney, Building G08, Sydney, NSW 2006, Australia.

The uniformly anisotropic media afforded by hydrogels are being increasingly exploited in analytical (structure elucidation) nuclear magnetic resonance (NMR) spectroscopy, and in studies of mechanosensitive biophysical and biochemical properties of living cells. The 9Be NMR parameters of beryllium fluoride complexes formed in aqueous solutions are sensitive markers of the anisotropic molecular environments produced by gelatin gels. The electric quadrupole moment of the 9Be nucleus (spin I = 3/2) interacts with the electric field gradient tensor in a stretched (or compressed) gel, giving rise to the splitting of peaks in 9Be NMR spectra. Read More

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Hydroxyl Radical Generation Through the Fenton-Like Reaction of Hematin- and Catechol-Functionalized Microgels.

Chem Mater 2020 Oct 4;32(19):8182-8194. Epub 2020 Sep 4.

Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931, USA.

Hydroxyl radical (OH) is a potent reactive oxygen species with the ability to degrade hazardous organic compounds, kill bacteria, and inactivate viruses. However, an off-the-shelf, portable, and easily activated biomaterial for generating OH does not exist. Here, microgels were functionalized with catechol, an adhesive moiety found in mussel adhesive proteins, and hematin (HEM), a hydroxylated Fe ion-containing porphyrin derivative. Read More

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October 2020

Establishment of an ATLL cell line (YG-PLL) dependent on IL-2 and IL-4, which are replaced by OX40-ligand HK with poly-L-histidine and dermatan sulfate.

J Clin Exp Hematop 2021 Jul 31. Epub 2021 Jul 31.

Department of Hematology and Cell Therapy, Aichi Cancer Center Hospital, Nagoya, Aichi, Japan.

We established an IL-2 and IL-4 (IL2/4) - dependent adult T-cell leukemia/lymphoma (ATLL) cell line (YG-PLL) by adding poly-L-lysine (PLL) to the culture medium. YG-PLL originates from lymphoma cells and contains a defective HTLV-I proviral genome. Although YG-PLL cannot survive without IL-2/4, the follicular dendritic cell (FDC)-like cell line HK expressing OX40-ligand gene (OX40LHK) inhibited their death in the presence of soluble neutral polymers. Read More

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Low-pressure highly permeable polyester loose nanofiltration membranes tailored by natural carbohydrates for effective dye/salt fractionation.

J Hazard Mater 2021 Jul 23;421:126716. Epub 2021 Jul 23.

Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium; Faculty of Engineering and the Built Environment, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa. Electronic address:

With the continuous pressure of water contamination caused by textile industry, loose nanofiltration (LNF) membranes prepared by green materials with an extraordinary water permeability are highly desirable for the recovery and purification of dyes and salts. In this work, low-pressure LNF membranes with ultrahigh permeability were fabricated via one-step interfacial polymerization (IP), in which inexpensive natural carbohydrate-derived sugars with large size and low reactivity were utilized as aqueous monomers to design selective layer. A systematic characterization by chemical analysis and optical microscopy demonstrated that the formed polyester film features not only loosen the structure, but also results in a hydrophilic and negatively charged surface. Read More

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Extraction of the antioxidant phytocomplex from wine-making by-products and sustainable loading in phospholipid vesicles specifically tailored for skin protection.

Biomed Pharmacother 2021 Jul 29;142:111959. Epub 2021 Jul 29.

Department of Life and Environmental Sciences, University of Cagliari, Via Ospedale 72, 09124 Cagliari, Italy.

The present study is aimed at valorizing grape pomace, one of the most abundant winery-making by-products of the Mediterranean area, through the extraction of the main bioactive compounds from the skin of grape pomace and using them to manufacture innovative nanoformulations capable of both avoiding skin damages and promoting skincare. The phytochemicals were recovered through maceration in hydroethanolic solution. Catechin, quercetin, fisetin and gallic acid, which are known for their antioxidant power, were detected as the main compounds of the extract. Read More

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Quercetin and piperine enriched nanostructured lipid carriers (NLCs) to improve apoptosis in oral squamous cellular carcinoma (FaDu cells) with improved biodistribution profile.

Eur J Pharmacol 2021 Jul 29:174400. Epub 2021 Jul 29.

Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Guwahati, Changsari, Kamrup, Assam, India. Electronic address:

Oral squamous cellular carcinoma (OSCC) is considered a life-threatening disease with detection in late stages, which forces us to opt for dangerous treatment with a combination of chemotherapy and radiotherapy. Herbal components such as piperine and quercetin are derived from edible sources, proving their anticancer potential against oral cancer cells in vitro. Encapsulation into lipid matrix-mediated nanostructured lipid carriers (NLCs) can make both drugs bio-accessible. Read More

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A core-shell nanoplatform as a nonviral vector for targeted delivery of genes to the retina.

Acta Biomater 2021 Jul 27. Epub 2021 Jul 27.

School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, PR China. Electronic address:

Retinal diseases, including age-related macular degeneration (AMD), are a major cause of blindness. Efficient delivery of therapeutic genes to retinal cells to treat retinal disease is a formidable challenge. In this study, we developed a core-shell nanoplatform composed of a core and two external layers for targeted delivery of the gene to the retina. Read More

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Optimized synthesis of lignin sulfonate nanoparticles by solvent shifting method and their application for adsorptive removal of dye pollutant.

Chemosphere 2021 Jul 15;285:131576. Epub 2021 Jul 15.

Department of Chemical Engineering, University of Mohaghegh Ardabili, Ardabil, Iran.

Synthesis of value added products from wastes is of importance from different perspectives. Wood and paper industry produces tons of wastewaters that contains lignin. In this paper, we report a new approach, called solvent-shifting method, to synthesize lignin sulfonate nanoparticles (LS-NPs). Read More

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Structure and mechanism of secondary sulfonamide binding to carbonic anhydrases.

Eur Biophys J 2021 Jul 30. Epub 2021 Jul 30.

Department of Biothermodynamics and Drug Design, Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio 7, 10257, Vilnius, Lithuania.

Zinc-containing metalloenzyme carbonic anhydrase (CA) binds primary sulfonamides with extremely high, up to picomolar, affinity by forming a coordination bond between the negatively charged amino group and the zinc ion and making hydrogen bonds and hydrophobic contacts with other parts of the inhibitor molecule. However, N-methyl-substituted, secondary or tertiary sulfonamides bind CA with much lower affinity. In search for an explanation for this diminished affinity, a series of secondary sulfonamides were synthesized and, together with analogous primary sulfonamides, the affinities for 12 recombinant catalytically active human CA isoforms were determined by the fluorescent thermal shift assay, stopped-flow assay of the inhibition of enzymatic activity and isothermal titration calorimetry. Read More

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Transfer Matrix Model of pH Effects in Polymeric Complex Coacervation.

J Phys Chem B 2021 Jul 30. Epub 2021 Jul 30.

Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.

Oppositely charged polyelectrolytes can undergo an associative phase separation, in a process known as polymeric complex coacervation. This phenomenon is driven by the electrostatic attraction between polyanion and polycation species, leading to the formation of a polymer-dense coacervate phase and a coexisting polymer-dilute supernatant phase. There has been significant recent interest in the physical origin and features of coacervation; yet notably, experiments often use weak polyelectrolytes the charge state of which depends on solution pH, while theoretical or computational efforts typically assume strong polyelectrolytes that remain fully charged. Read More

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Montmorillonite promoted photodegradation of amlodipine in natural water via formation of surface complexes.

Chemosphere 2021 Jul 24;286(Pt 1):131641. Epub 2021 Jul 24.

State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China. Electronic address:

The photolysis of amlodipine (AML) as a ubiquitous pollutant in natural water has been extensively studied. Montmorillonite (MMT), a major component of suspended particles in surface aquifers, plays key roles in the natural transportation and transformation of organic contaminants in the environment. However, literature has scarcely focused on whether and how suspended particles affect the phototransformation of AML. Read More

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L-DOPA Dioxygenase Activity on 6-Substituted Dopamine Analogues.

Biochemistry 2021 Jul 29. Epub 2021 Jul 29.

Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, Tennessee 38112, United States.

Dioxygenase enzymes are essential protein catalysts for the breakdown of catecholic rings, structural components of plant woody tissue. This powerful chemistry is used in nature to make antibiotics and other bioactive materials or degrade plant material, but we have a limited understanding of the breadth and depth of substrate space for these potent catalysts. Here we report steady-state and pre-steady-state kinetic analysis of dopamine derivatives substituted at the 6-position as substrates of L-DOPA dioxygenase, and an analysis of that activity as a function of the electron-withdrawing nature of the substituent. Read More

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Label-Free Study of Protein Adsorption on Nanoparticles.

J Phys Chem B 2021 Jul 29. Epub 2021 Jul 29.

Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.

Improving the design of nanoparticles for use as drug carriers or biosensors requires a better understanding of the protein-nanoparticle interaction. Here, we present a new tool to investigate this interaction and without additional labeling of the proteins and/or nanoparticles. By combining nonresonant second-harmonic light scattering with a modified Langmuir model, we show that it is possible to gain insight into the adsorption behavior of blood proteins, namely fibrinogen, human serum albumin, and transferrin, onto negatively charged polystyrene nanoparticles. Read More

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[Biofilm Eradication Four-Step Strategy: Study of Using Self-Assembled Azithromycin/Rhamnolipid Nanoparticles for Removing Biofilm].

Sichuan Da Xue Xue Bao Yi Xue Ban 2021 Jul;52(4):598-604

School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou 510006, China.

Objective: To investigate the eradicative effect of self-assembled azithromycin/rhamnolipid nanoparticles (AZI-RHL NPs) on ( ) biofilm.

Methods: AZI-RHL NPs were prepared and characterized. The minimum inhibitory concentration (MIC) of AZI-RHL NPs on planktonic was measured by the broth microdilution method. Read More

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Effect of single nanoparticle-nanopore interaction strength on ionic current modulation.

Sens Actuators B Chem 2020 Dec 24;325. Epub 2020 Aug 24.

Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India.

Solid-state nanopores are rapidly emerging as promising platforms for developing various single molecule sensing applications. The modulation of ionic current through the pore due to translocation of the target molecule has been the dominant measurement modality in nanopore sensors. Here, we focus on the dwell time, which is the duration taken by the target molecule or particle to traverse the pore and study its dependence on the strength of interaction of the target with the pore using single gold nanoparticles (NPs) as targets interacting with a silicon nitride (SiN) nanopore. Read More

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December 2020

Functional Roles of Chelated Magnesium Ions in RNA Folding and Function.

Biochemistry 2021 Jul 28. Epub 2021 Jul 28.

Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.

RNA regulates myriad cellular events such as transcription, translation, and splicing. To perform these essential functions, RNA often folds into complex tertiary structures in which its negatively charged ribose-phosphate backbone interacts with metal ions. Magnesium, the most abundant divalent metal ion in cells, neutralizes the backbone, thereby playing essential roles in RNA folding and function. Read More

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Proton-Coupled Group Transfer Enables Concerted Protonation Pathways Relevant to Small-Molecule Activation.

Inorg Chem 2021 Jul 27. Epub 2021 Jul 27.

Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States.

The mechanistic identification of Nature's use of concerted reactions, in which all bond breaking and bond making occurs in a single step, has inspired rational designs for artificial synthetic transformations via pathways that bypass high-energy intermediates that would otherwise be thermodynamically and kinetically inaccessible. In this contribution we electrochemically activate an organometallic Ruthenium(II) complex to show that, in acetonitrile solutions, the movement of protons from weak Brønsted acids, such as water and methanol, is coupled with the transfer of its negatively charged counterpart to carbon dioxide (CO)-a process termed -to stoichiometrically produce a metal-hydride complex and a carbonate species. These previously unidentified pathways have played key roles in CO and proton reduction catalysis by enabling the generation of key intermediates such as hydrides and metallocarboxylic acids, while their applicability to carbon acids may provide alternative approaches in the electrosynthesis of chemical commodities via alkylation and carboxylation reactions. Read More

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Determination of Cr(VI) based on the peroxidase mimetic catalytic activity of citrate-capped gold nanoparticles.

Mikrochim Acta 2021 Jul 26;188(8):273. Epub 2021 Jul 26.

College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, 710054, China.

Highly negatively charged gold nanoparticles (AuNPs) are shown to have strong simulated oxidase activity and effectively boosted the oxidation of enzyme substrate 3,3',5,5'-tetramethylbenzidine (TMB) by hexavalent chromium ion Cr(VI), resulting in the formation of oxidation product with blue color. Based on this, a facile colorimetric assay was developed to detect Cr(VI) at a range 0.008~0. Read More

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An electrostatically regulated organic self-assembly for rapid and sensitive detection of heparin in serum.

Anal Methods 2021 Jul 27. Epub 2021 Jul 27.

Key Laboratory of Public Health Safety of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Public Health, Hebei University, Baoding 071002, P. R. China.

Heparin (Hep) is a highly negatively charged linear glycosaminoglycan involved in various physiological processes, especially blood coagulation. Hep is also a first-line drug for anticoagulation and prevention of thromboembolism, but its overdose will cause serious side effects. Herein, we designed a long-wavelength double-charged cationic fluorescent probe PYPN, and studied its aggregation state and detection performance for Hep. Read More

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Importance of Substrate-Particle Repulsion for Protein-Templated Assembly of Metal Nanoparticles.

Langmuir 2021 Aug 26;37(30):9111-9119. Epub 2021 Jul 26.

Department of Chemistry, University of Washington, Seattle, Washington 98195, United States.

We study the protein-directed assembly of colloidal gold nanoparticles on designed protein nanofiber templates. Using sequential assembly on glass substrates, we attach positively charged gold nanoparticles to protein nanofibers engineered to have a high density of negatively charged surface residues. Using a combination of electron and optical microscopy, we measure the density of particle attachment and characterize binding specificity. Read More

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Engineering Dendrimer-Templated, Metal-Organic Framework-Confined Zero-Valent, Transition-Metal Catalysts.

ACS Appl Mater Interfaces 2021 Jul 26. Epub 2021 Jul 26.

Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.

We describe and experimentally illustrate a strategy for synthesizing reactant-accessible, supported arrays of well-confined, sub-nanometer to 2 nm, metal(0) clusters and particles-here, copper, palladium, and platinum. The synthesis entails (a) solution-phase binding of metal ions by a generation-2 poly(amidoamine) (PAMAM) dendrimer, (b) electrostatic uptake of metalated, solution-dissolved, and positively charged dendrimers by the negatively charged pores of a zirconium-based metal-organic framework (MOF), NU-1000, and (c) chemical reduction of the incorporated metal ions. The pH of the unbuffered solution is known to control the overall charges of both the dendrimer guests and the hierarchically porous MOF. Read More

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The influence of humic and fulvic acids on polytetrafluoroethylene-adsorbed arsenic: a mechanistic study.

Environ Sci Pollut Res Int 2021 Jul 26. Epub 2021 Jul 26.

Department of Civil and Environmental Engineering, Shantou University, Shantou, 515063, China.

The large-scale use of polytetrafluoroethylene has resulted in ever-increasing amounts of polytetrafluoroethylene (PTFE) microplastic particles entering the environment. Given that the environment is polluted with arsenic (As(III)), and that the environment contains significant levels of humic acid (HA) and fulvic acid (FA), how PTFE and As(III) in water interacting in the presence of HA and FA needs to be urgently investigated. The results showed that As(III) was adsorbed by PTFE in the presence of HA and FA more markedly than the absence of them Adsorption equilibrium was reached at approximately 960 min and the adsorption isotherms were found to be best fitted by the Toth model. Read More

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Biogenic Synthesis and Catalytic Efficacy of Silver Nanoparticles Based on Peel Extracts of Fruit.

ACS Omega 2021 Jul 9;6(28):18260-18268. Epub 2021 Jul 9.

Department of Chemistry and Chemical Engineering, Graduate School of Science and Engineering, Yamagata University, 4-3-16, Jonan, Yonezawa, Yamagata 992-8510, Japan.

Biogenically synthesized silver nanoparticles (AgNP) increase the fascination over chemical ones due to their facile and green synthetic process. This study reports the development of an eco-friendly and cost-effective synthesis of AgNPs using an aqueous extract of fruit peel, an agricultural waste, as a sole agent with both reducing and capping abilities. The formation of AgNPs was verified by the surface plasmon resonance peak at 426 nm in the UV-vis spectrum, X-ray diffraction pattern, and transmission electron micrography images. Read More

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Synthesis of charged chitosan nanoparticles as functional biolubricant.

Colloids Surf B Biointerfaces 2021 Jul 15;206:111973. Epub 2021 Jul 15.

State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China. Electronic address:

Osteoarthritis has been a major disease in recent years, which is mainly related to the breakdown of the lubrication function of the cartilage sliding interface, along with the inflammation of the joint capsule. In this paper, one kind of novel biomimetic nanoparticles (NPs) lubricant, named CS-PS, is synthesized through chemically grafting hydrophilic sulfonic acid (SO) groups onto the surface of biocompatible and biodegradable chitosan (CS) NPs. Compared with control CS NPs, the as-synthesized CS-PS NPs exhibits excellent hydration and stability because of negatively charged surface zeta potential, along with extraordinary lubrication performance in water for realizing a super-low friction coefficient (COF) as ∼0. Read More

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Liquid-like chromatin in the cell: What can we learn from imaging and computational modeling?

Curr Opin Struct Biol 2021 Jul 22;71:123-135. Epub 2021 Jul 22.

Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK; Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK; Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK. Electronic address:

Chromatin in eukaryotic cells is a negatively charged long polymer consisting of DNA, histones, and various associated proteins. With its highly charged and heterogeneous nature, chromatin structure varies greatly depending on various factors (e.g. Read More

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An integrated giant polyoxometalate complex for photothermally enhanced catalytic oxidation.

Sci Adv 2021 Jul 23;7(30). Epub 2021 Jul 23.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China.

A strategy integrating near infrared (NIR) photothermal and catalytic effects within one active center beyond ultraviolet and visible light is proposed without the combination of separated photothermal transformation components. A giant polyoxomolybdate, which has high NIR photothermal conversion efficiency, is selected as the model catalyst, while a cationic β-cyclodextrin is used to cover its negatively charged surface electrostatically. Under NIR light radiation, the designed catalyst increases catalytic activity of cyclohexene oxidation under O atmosphere in water. Read More

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