Transformation of Schwertmannite to erdite nanorod via an alkaline dissolution–recrystallization process for the effective adsorption of oxytetracycline

2021 ◽  
Author(s):  
Jiancong Liu ◽  
Yanwen Liu ◽  
Zhonglei Zhang ◽  
Xiaoshu Wang ◽  
Ying Wang ◽  
...  
Keyword(s):  
Smooth Surface ◽  
Side Chain ◽  
Recrystallization Process ◽  
Amino Groups ◽  
Surface Functional Groups ◽  
Alkaline Dissolution ◽  
Mine Wastewater ◽  
Sh Group ◽  
Potential Applications ◽  
Nanorod Particles

Schwertmannite (schw) is a common Fe-bearing mineral in the precipitation of mine wastewater and/or steel pickling wastewater. It could be easily converted to goethite and hematite via heating or hydrothermal treatment and could be used as adsorbent to remove contaminants from wastewater. Herein, the spherical schw was converted into erdite nanorod by a simple hydrothermal method with the addition of Na2S. Schw was spherical particle with a size of 0.4–1.5 [Formula: see text]m. After treatment, it was converted to erdite nanorod particles with 100 nm diameter and 200 nm length. By adding MnO2 at the MMn/Fe ratio of 1, erdite nanorod grew radially to 1–1.5 [Formula: see text]m, whereas MnO2 was reductively dissolved and recrystallized to rambergite. In the absence of Fe, MnO2 was directly transformed to octahedral alabandite. The product EN-0, prepared without MnO2, showed the optimal qmax of oxytetracycline (OTC, 7479.6 mg/g), which was 12 times that of schw. In OTC-bearing solution, erdite was unstable and automatically hydrolyzed to generate Fe–SH/Fe–OH-bearing flocs, and it exhibited abundant surface functional groups for OTC adsorption. Subsequently, the hydroxyl and amino groups on the side chain of OTC would also be complexed with the Fe–SH group to generate an OTC–Fe–S ligand, in the form of flake-like particles with a smooth surface. The formed Mn-bearing minerals, for example, rambergite and alabandite, also complexed with OTC as OTC–Mn–S ligands to form quadrangular prism with shoulder and length of 10 [Formula: see text]m and 20–100 [Formula: see text]m, respectively. Spherical schw was converted into a well-crystallized erdite nanorod with the addition of MnO2, and the product showed potential applications in OTC-bearing wastewater treatment.

scholarly journals Unusual Structural Features in the Adduct of Dirhodium Tetraacetate with Lysozyme

2021 ◽  
Vol 22 (3) ◽  
pp. 1496
Author(s):  
Domenico Loreto ◽  
Giarita Ferraro ◽  
Antonello Merlino
Keyword(s):  
Anticancer Agents ◽  
Structural Features ◽  
Side Chain ◽  
Side Chains ◽  
Valuable Insight ◽  
Experimental Conditions ◽  
Egg White Lysozyme ◽  
Potential Applications ◽  
Model Protein ◽  
Hen Egg White

The structures of the adducts formed upon reaction of the cytotoxic paddlewheel dirhodium complex [Rh2(μ-O2CCH3)4] with the model protein hen egg white lysozyme (HEWL) under different experimental conditions are reported. Results indicate that [Rh2(μ-O2CCH3)4] extensively reacts with HEWL:it in part breaks down, at variance with what happens in reactions with other proteins. A Rh center coordinates the side chains of Arg14 and His15. Dimeric Rh–Rh units with Rh–Rh distances between 2.3 and 2.5 Å are bound to the side chains of Asp18, Asp101, Asn93, and Lys96, while a dirhodium unit with a Rh–Rh distance of 3.2–3.4 Å binds the C-terminal carboxylate and the side chain of Lys13 at the interface between two symmetry-related molecules. An additional monometallic fragment binds the side chain of Lys33. These data, which are supported by replicated structural determinations, shed light on the reactivity of dirhodium tetracarboxylates with proteins, providing useful information for the design of new Rh-containing biomaterials with an array of potential applications in the field of catalysis or of medicinal chemistry and valuable insight into the mechanism of action of these potential anticancer agents.

scholarly journals Fabrication and Characterization of Lignin/Dendrimer Electrospun Blended Fiber Mats

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 518
Author(s):  
Somaye Akbari ◽  
Addie Bahi ◽  
Ali Farahani ◽  
Abbas S. Milani ◽  
Frank Ko
Keyword(s):  
Thermal Characteristics ◽  
Dendritic Polymers ◽  
Amino Groups ◽  
Fiber Mats ◽  
Potential Applications ◽  
Solution Electrospinning ◽  
Nanofiber Mats ◽  
Softwood Kraft Lignin ◽  
First Time

Blending lignin as the second most abundant polymer in Nature with nanostructured compounds such as dendritic polymers can not only add value to lignin, but also increase its application in various fields. In this study, softwood Kraft lignin/polyamidoamine dendritic polymer (PAMAM) blends were fabricated by the solution electrospinning to produce bead-free nanofiber mats for the first time. The mats were characterized through scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, zeta potential, and thermogravimetry analyses. The chemical intermolecular interactions between the lignin functional groups and abundant amino groups in the PAMAM were verified by FTIR and viscosity measurements. These interactions proved to enhance the mechanical and thermal characteristics of the lignin/PAMAM mats, suggesting their potential applications e.g. in membranes, filtration, controlled release drug delivery, among others.

Enhanced stability and gene silencing ability of siRNA-loaded polyion complexes formulated from polyaspartamide derivatives with a repetitive array of amino groups in the side chain

Biomaterials ◽  
2012 ◽  
Vol 33 (9) ◽  
pp. 2770-2779 ◽  
Author(s):  
Tomoya Suma ◽  
Kanjiro Miyata ◽  
Takehiko Ishii ◽  
Satoshi Uchida ◽  
Hirokuni Uchida ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Side Chain ◽  
Amino Groups ◽  
Enhanced Stability ◽  
Polyion Complexes

scholarly journals Chemical Reactivities of ortho-Quinones Produced in Living Organisms: Fate of Quinonoid Products Formed by Tyrosinase and Phenoloxidase Action on Phenols and Catechols

2020 ◽  
Vol 21 (17) ◽  
pp. 6080 ◽  
Author(s):  
Shosuke Ito ◽  
Manickam Sugumaran ◽  
Kazumasa Wakamatsu
Keyword(s):  
Nucleophilic Addition ◽  
Quinone Methide ◽  
Side Chain ◽  
Amino Groups ◽  
Melanin Biosynthesis ◽  
Fast Reactions ◽  
Carcinogenic Effects ◽  
Oxidation Of Phenols ◽  
Living Organisms ◽  
Cellular Components

Tyrosinase catalyzes the oxidation of phenols and catechols (o-diphenols) to o-quinones. The reactivities of o-quinones thus generated are responsible for oxidative browning of plant products, sclerotization of insect cuticle, defense reaction in arthropods, tunichrome biochemistry in tunicates, production of mussel glue, and most importantly melanin biosynthesis in all organisms. These reactions also form a set of major reactions that are of nonenzymatic origin in nature. In this review, we summarized the chemical fates of o-quinones. Many of the reactions of o-quinones proceed extremely fast with a half-life of less than a second. As a result, the corresponding quinone production can only be detected through rapid scanning spectrophotometry. Michael-1,6-addition with thiols, intramolecular cyclization reaction with side chain amino groups, and the redox regeneration to original catechol represent some of the fast reactions exhibited by o-quinones, while, nucleophilic addition of carboxyl group, alcoholic group, and water are mostly slow reactions. A variety of catecholamines also exhibit side chain desaturation through tautomeric quinone methide formation. Therefore, quinone methide tautomers also play a pivotal role in the fate of numerous o-quinones. Armed with such wide and dangerous reactivity, o-quinones are capable of modifying the structure of important cellular components especially proteins and DNA and causing severe cytotoxicity and carcinogenic effects. The reactivities of different o-quinones involved in these processes along with special emphasis on mechanism of melanogenesis are discussed.

Cytotoxicity and DNA-binding property of water-soluble naphthalene diimide derivatives bearing 2-oligoethoxy ethanamine side chain end-labeled with tertiary amino groups

2013 ◽  
Vol 23 (5) ◽  
pp. 2277-2286 ◽  
Author(s):  
Haiying Wei ◽  
Mengjiao Lv ◽  
Xiaoxu Duan ◽  
Shuai Li ◽  
Yuchao Yao ◽  
...  
Keyword(s):  
Dna Binding ◽  
Water Soluble ◽  
Side Chain ◽  
Binding Property ◽  
Amino Groups ◽  
Naphthalene Diimide ◽  
Dna Binding Property ◽  
Tertiary Amino

scholarly journals The effect of polyamines on the poly(adenylic acid)-induced inhibition of ribonuclease activity

1981 ◽  
Vol 193 (1) ◽  
pp. 325-337 ◽  
Author(s):  
T P Karpetsky ◽  
K K Shriver ◽  
C C Levy
Keyword(s):  
Human Plasma ◽  
Segment Length ◽  
Side Chain ◽  
Amino Groups ◽  
Human Spleen ◽  
Low Concentrations ◽  
Degradation Rates ◽  
Adenylic Acid ◽  
Bovine Pancreas ◽  
Terminal Poly

Segments of poly(A) at the 3′-termini of 5 S rRNA inhibit the activities of ribonucleases from Citrobacter, Enterobacter, bovine pancreas, human spleen and human plasma. Certain polyamines, or compounds containing polyamine substructures, mediate reversal of this inhibition. Effective compounds contain three amino groups, at least two of which are charged and are separated from the others by no less than three carbon atoms. Spermidine and 9-aminoacridines, which contain substituted propyl- or butylamino moieties at the 9-amino position and which bear two positive charges per molecule, are efficacious at low concentrations (5 microM). A decrease in effectiveness is associated with the removal of one aromatic ring from the 9-aminoacridines. However, the resulting 4-aminoquinolines, unlike the acridines, do not inhibit enzyme activity when present in concentrations above 30 microM. Relocating the diamino side chain from the 4- to the 8-position of the quinoline nucleus causes a decrease in charge density to +1, with the result that such compounds are ineffective. The orders of polyamine efficacy of reversal of inhibition were similar for enzymes from Citrobacter, bovine pancreas, and human plasma, and paralleled the order of binding of polyamines to either poly(A) or 5 S rRNA. This was not the case with Enterobacter and human spleen RNAases, indicating that the identity of the most effective polyamines depends on the RNAase studied. The combination of variable 3′-terminal poly(A) segment length and polyamine identity and concentration constitutes a system by which RNAase activities, and, therefore, substrate-degradation rates, may be easily varied.

Effect of different photoinitiators on the properties of UV-cured electromagnetic shielding composites

2015 ◽  
Vol 35 (3) ◽  
pp. 209-222 ◽  
Author(s):  
Yuting Dai ◽  
Fengxian Qiu ◽  
Lili Wang ◽  
Jinliang Zhao ◽  
Dongya Yang ◽  
...  
Keyword(s):  
Electromagnetic Shielding ◽  
Conductive Network ◽  
Surface Functional Groups ◽  
Low Resistivity ◽  
Polyurethane Acrylate ◽  
Potential Applications ◽  
Different Content ◽  
Conductive Particles ◽  
Shielding Composites ◽  
Active Diluents

Abstract A series of UV-cured electromagnetic shielding composites (UV-EMSC) containing different content of graphene oxide (GO) were prepared with oligomer, acrylate active diluents and different photoinitiators (Darocur 1173, Irgacure 184 or Irgacure 651). To fabricate conductive oligomer with low resistivity, polyurethane-acrylate (PUA) was used as the polymer matrix to help construct two-dimensional conductive networks consisting of GO. For forming conductive network structure, the surface functional groups (-OH, -COOH) of GO served as slightly conductive particles bonded with -NCO from the chain of polyurethane. The UV-EMSC exhibited a low resistivity of approximately 402 Ω·cm and an outstanding enhanced electrical conductivity of 249 mS/m at a GO content of 0.0200%. The effects of different photoinitiators on the properties of UV-cured films were investigated. The results indicate that the prepared UV-EMSC has great potential applications in different regions, such as in coatings of electronic, electrical, communications, plastic coatings and wood finishes.

Dynamics of Lysine Side-Chain Amino Groups in a Protein Studied by Heteronuclear1H−15N NMR Spectroscopy

2011 ◽  
Vol 133 (4) ◽  
pp. 909-919 ◽  
Author(s):  
Alexandre Esadze ◽  
Da-Wei Li ◽  
Tianzhi Wang ◽  
Rafael Brüschweiler ◽  
Junji Iwahara
Keyword(s):  
Nmr Spectroscopy ◽  
Side Chain ◽  
15N Nmr ◽  
Amino Groups ◽  
Lysine Side Chain ◽  
15N Nmr Spectroscopy

A Novel Light-Emitting Mixed-Ligand Iridium(III) Complex With a Polymeric Terpyridine-PEG Macroligand: Synthesis And Characterization

2004 ◽  
Vol 846 ◽  
Author(s):  
Elisabeth Holder ◽  
Veronica Marin ◽  
Michael A. R. Meier ◽  
Dmitry Kozodaev ◽  
Ulrich S. Schubert
Keyword(s):  
Model Material ◽  
Mixed Ligand ◽  
Side Chain ◽  
Poly Ethylene Glycol ◽  
Active Centers ◽  
Light Emitting ◽  
Potential Applications ◽  
Poly Ethylene ◽  
Thin Film Devices

ABSTRACTThe synthesis of mixed ligand orthometalated iridium(III) complexes as well as the characterization of their electro-optical properties is briefly illustrated. The cyclic voltammetry results exemplify an enhanced stability of the complex with a poly(ethylene glycol (PEG) side chain compared to the corresponding organometallic model material. Less degradation of the electrically active centers was found to occur on the electrode surface. Furthermore the morphology of thin films of the described polymeric material was investigated with respect to potential applications in thin film devices.

Sign in / Sign up

Export Citation Format

Share Document