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Cationic polymers

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https://www.readbyqxmd.com/read/28448845/use-of-aqueous-two-phase-peg-salt-systems-for-the-removal-of-anionic-surfactant-from-effluents
#1
Gabriella Frade Murari, Jussara Alves Penido, Heriveltom Morais da Silva, Bruno Eduardo Lôbo Baêta, Sérgio Francisco de Aquino, Leandro Rodrigues de Lemos, Guilherme Dias Rodrigues, Aparecida Barbosa Mageste
Linear alkylbenzene sulfonates (LAS) are synthetic anionic surfactants that are extensively used in many industries. As a result, large volumes of effluents containing high levels of these compounds are discharged into water bodies, causing risks to aquatic flora and fauna. Then, there is a need for environmentally safe and economically viable technologies for the removal of LAS from aqueous matrices. The present work evaluates the use of aqueous two-phase systems (ATPS) composed of PEG and sulfate salts for this purpose, considering the effects of tie line length (TLL), molar mass of polymer, and type of cation-forming salt on the partitioning behavior of LAS...
April 24, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28444923/anaerobic-respiration-on-self-doped-conjugated-polyelectrolytes-impact-of-chemical-structure
#2
Nathan D Kirchhofer, Samantha R McCuskey, Cheng-Kang Mai, Guillermo C Bazan
We probe anaerobic respiration of bacteria in the presence of conjugated polyelectrolytes (CPEs). Three different CPEs were used to probe how structural variations impact biocurrent generation from Shewanella oneidensis MR-1. For the self-doped anionic CPE only, absorption spectroscopy shows that the addition of S. oneidensis MR-1 leads to the disappearance of the polaron (radical cation) band at >900 nm and an increase in the band at 735 nm due to the neutral species, consistent with electron transfer from microbe to polymer...
April 26, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28441860/smart-luminescent-coordination-polymers-towards-multi-mode-logic-gates-time-resolved-tribochromic-and-excitation-dependent-fluorescence-phosphorescence-emission
#3
Yongsheng Yang, Ke-Zhi Wang, Dongpeng Yan
In this work, we propose that lanthanide cations (such as Eu3+ and Tb3+) doped long-afterglow coordination polymer (CP) can be an effective way to design multi-mode optical logic gates based on their tunable fluorescence/phosphorescence transformation and state-dependent emission. First, multi-color and white-light luminescence across the blue/green/yellow/red visible regions can be obtained by balancing the co-doping ratio of Eu3+/Tb3+ cations and suitable excitations. Additionally, new mechanochromic Eu-Cd-CP was developed based on the mechanism of change in structural symmetry...
April 26, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28440650/comprehensive-computational-and-experimental-analysis-of-biomaterial-towards-the-behavior-of-imidazolium-based-ionic-liquids-an-interplay-between-hydrophilic-and-hydrophobic-interactions
#4
Reddicherla Umapathi, Suresh B Vepuri, Pannuru Venkatesu, Mahmoud E S Soliman
To provide insights into the aggregation behavior, hydration tendency and variation in phase transition temperature produced by the addition of ionic liquids (ILs) to poly(N-isopropylacrylamide) (PNIPAM) aqueous solution, systematic physicochemical studies, and molecular dynamic simulations were carried out. The influence of ILs possessing same [Cl]- anion and a set of cation [Cnmim]+ with increasing alkyl chain length such as 1-ethyl-3-methylimidazolium ([Emim]+), 1-allyl-3-methylimidazolium ([Amim]+), 1-butyl-3-methylimidazolium ([Bmim]+), 1-hexyl-3-methylimidazolium ([Hmim]+), 1-benzyl-3-methylimidazolium ([Bzmim]+), and 1- decyl-3-methylimidazolium ([Dmim] +) on the phase transition of PNIPAM was monitored by the aid of UV-visible absorption spectra, fluorescence intensity spectra, viscosity (ɳ), dynamic light scattering (DLS) and Fourier transform infrared (FTIR) spectroscopy...
April 25, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28431898/serum-potassium-concentrations-importance-of-normokalaemia
#5
REVIEW
Manuel Heras, María José Fernández-Reyes
Abnormalities in potassium concentrations are associated with morbidity and mortality. In recent years it has been considered that small variations in serum potassium concentrations within normal intervals may also be associated with mortality. Strategies for achieving normokalaemia include dietary measures, limiting the use of potassium retaining drugs, and use of conventional cation exchange resins (calcium/sodium polystyrene sulfonate) and/or the new non-absorbed cation exchange polymer (patiromer).
April 18, 2017: Medicina Clínica
https://www.readbyqxmd.com/read/28426222/structural-and-dynamical-properties-of-tetra-alkyl-ammonium-bromide-aqueous-solutions-a-molecular-dynamics-simulation-study-using-a-polarizable-force-field
#6
Dengpan Dong, Justin B Hooper, Dmitry Bedrov
Understanding the behavior of aqueous solutions containing tetra-alkyl ammonium (TAA) cations is of great significance in a number of applications, including polymer membranes for fuel cells. In this work, a polarizable force field has been used to preform atomistic molecular dynamics (MD) simulations of aqueous solutions containing tetra-methyl ammonium (TMA) or tetra-butyl ammonium (TBA) cations and Br counterions. Extensive MD simulations of TMA-Br/water and TBA-Br/water systems were conducted as a function of solution composition (ion pair : water molar ratios of 1:10, 1:20, 1:30, 1:63, 1:500) at atmospheric pressure and 298K...
April 20, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28425679/soft-interactions-and-volume-exclusion-by-polymeric-crowders-can-stabilize-or-destabilize-transient-structure-in-disordered-proteins-depending-on-polymer-concentration
#7
Farai I Rusinga, David D Weis
The effects of macromolecular crowding on the transient structure of intrinsically disordered proteins is not well-understood. Crowding by biological molecules inside cells could modulate transient structure and alter IDP function. Volume exclusion theory and observations of structured proteins suggest that IDP transient structure would be stabilized by macromolecular crowding. Amide hydrogen exchange (HX) of IDPs in highly concentrated polymer solutions would provide valuable insights into IDP transient structure under crowded conditions...
April 20, 2017: Proteins
https://www.readbyqxmd.com/read/28423276/supramolecular-%C3%AE-sheets-stabilized-protein-nanocarriers-for-drug-delivery-and-gene-transfection
#8
Yuan Ping, Dawei Ding, Ricardo A N S Ramos, Harini Mohanram, Kanagavel Deepankumar, Jianqing Gao, Guping Tang, Ali Miserez
Suckerin proteins, recently discovered in the sucker ring teeth of squids, represent a family of promising structural biomacromolecules that can form supramolecular networks stabilized by nanoconfined β-sheets. Exploiting this feature as well as their specific amino acid composition, we demonstrate that artificial suckerin-19 (S-19) can be engineered into nanocarriers for efficient drug delivery and gene transfection in vitro and in vivo. First, we demonstrate that S-19 self-assembles into β-sheet stabilized nanoparticles with controlled particle sizes of 100-200 nm that are able to encapsulate hydrophobic drugs for pH-dependent release in vitro, and that can effectively inhibit tumor growth in vivo...
April 26, 2017: ACS Nano
https://www.readbyqxmd.com/read/28423187/characterization-of-the-binding-capacity-of-mercurial-species-in-lactobacillus-strains
#9
Cristina Alcántara, Carlos Jadán-Piedra, Dinoraz Vélez, Vicenta Devesa, Manuel Zúñiga, Vicente Monedero
BACKGROUND: Metal sequestration by bacteria has been proposed as a strategy to counteract metal contamination in foodstuffs. Lactobacilli can interact with metals, but studies with important foodborne metals such as inorganic [Hg(II)] or organic (CH3 Hg) mercury are lacking. Lactobacilli were evaluated for their potential to bind these contaminants and the nature of the interaction was assessed by the use of metal competitors, chemical and enzymatical treatments and mutants affected in the cell-wall structure...
April 19, 2017: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/28422484/direct-synthesis-of-dextran-based-antibacterial-hydrogels-for-extended-release-of-biocides-and-eradication-of-topical-biofilms
#10
Jiaul Hoque, Jayanta Haldar
Cationic small molecular biocides have been developed as promising antibiofilm agents because of their tunability in chemical structures and ability to disrupt established biofilms. However, the impact of biocides in antibiofilm treatment is largely limited due to lack of an effective delivery system that can ensure sustained release of biocide at the target site. Herein we report biocide-encapsulated antibacterial and antibiofilm hydrogel that acts as efficient delivery vehicle for the biocide and eradicates matured bacterial biofilm...
April 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28422203/a-nanoporous-ag-i-coordination-polymer-for-selective-adsorption-of-carcinogenic-dye-acid-red-26
#11
Cheng-Peng Li, Hang Zhou, Si Wang, Hong-Han Yuan, Su-Zhen Zhang, Miao Du
A cationic Ag(i) coordination polymer with 1D nanoporous channels (ca. 1.22 nm diameter) shows the selective and complete removal of carcinogenic dye Acid Red 26 from aqueous solution upon the size-exclusion and charge-matching effect.
April 19, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28421747/multifunctional-probe-based-on-cationic-conjugated-polymers-for-nitroreductase-related-analysis-sensing-hypoxia-diagnosis-and-imaging
#12
Xiaoqian Zhang, Qi Zhao, Yanru Li, Xinrui Duan, Yanli Tang
Nitroreductase (NTR) is overexpressed in hypoxic tumors. Moreover, hypoxia is usually considered as the most important feature of various diseases. Thus, it is important to build a sensitive and selective method for NTR detection and hypoxia diagnosis. Herein, a new cationic conjugated polymer (PBFBT-NP) with p-nitrophenyl group in the side chain was designed and synthesized as a fluorescent probe for the detection of NTR. In the absence of NTR, the fluorescence of PBFBT-NP was quenched due to photoinduced electron transfer (PET)...
April 27, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28418662/partial-in-situ-reduction-of-copper-ii-resulting-in-one-pot-formation-of-2d-neutral-and-3d-cationic-copper-i-iodide-pyrazine-coordination-polymers-structure-and-emissive-properties
#13
Iurie L Malaestean, Victor Ch Kravtsov, Janusz Lipkowski, Elena Cariati, Stefania Righetto, Daniele Marinotto, Alessandra Forni, Marina S Fonari
On the way to copper(I) iodide coordination polymers with specific luminescent properties, the in situ reduction of Cu(II) in the presence of KI and bidentate N-heteroatomic ligand, either pyrazine (pyz) or 4,4'-bipyridine (bpy), resulted in one two-dimensional and two three-dimensional new coordination networks. Starting from Cu(NO3)2·3H2O in the presence of pyz, successive precipitation of known yellow [(Cu(I)I)2(pyz)]n, new orange [Cu(I)I(pyz)]n, and new dark blue {[Cu(I)(pyz)2]·I5}n polymeric solids was observed...
April 18, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28418580/effect-of-surfactant-species-and-electrophoretic-medium-composition-on-the-electrophoretic-behavior-of-neutral-and-water-insoluble-linear-synthetic-polymers-in-nonaqueous-capillary-zone-electrophoresis
#14
Nao Fukai, Shinya Kitagawa, Hajime Ohtani
We have recently demonstrated the separation of neutral and water-insoluble linear synthetic polymers in non-aqueous capillary zone electrophoresis (NACZE) using a cationic surfactant of cetyltrimethylammonium chloride (CTAC). In this study, eight ionic surfactants were investigated for the separation of four synthetic polymers (polystyrene, polymethylmethacrylates, polybutadiene, and polycarbonate); only three surfactants (CTAC, dimethyldioctadecylammonium bromide, and sodium dodecylsulfate) caused their separation...
April 18, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28416888/tailoring-pore-size-and-chemical-interior-of-near-1-nm-sized-pores-in-a-nanoporous-polymer-based-on-a-discotic-liquid-crystal
#15
Subham Bhattacharjee, Jody A M Lugger, Rint P Sijbesma
A triazine based disc shaped molecule with two hydrolyzable units, imine and ester groups, was polymerized via acyclic diene metathesis in the columnar hexagonal (Colhex) LC phase. Fabrication of a cationic nanoporous polymer (pore diameter ∼1.3 nm) lined with ammonium groups at the pore surface was achieved by hydrolysis of the imine linkage. Size selective aldehyde uptake by the cationic porous polymer was demonstrated. The anilinium groups in the pores were converted to azide as well as phenyl groups by further chemical treatment, leading to porous polymers with neutral functional groups in the pores...
April 11, 2017: Macromolecules
https://www.readbyqxmd.com/read/28414912/observation-of-photovoltaic-action-from-photoacid-modified-nafion-due-to-light-driven-ion-transport
#16
William White, Christopher D Sanborn, Ronald S Reiter, David M Fabian, Shane Ardo
Replacing passive ion-exchange membranes, like Nafion, with membranes that use light to drive ion transport would allow membranes in photoelectrochemical technologies to serve in an active role. Toward this, we modified per-fluorosulfonic acid ionomer membranes with organic pyrenol-based photoacid dyes to sensitize the membranes to visi-ble light and initiate proton transport. Covalent modification of the membranes was achieved by reacting Nafion sul-fonyl fluoride poly(perfluorosulfonyl fluoride) membranes with 8-hydroxypyrene-1,3,6-tris(2-aminoethylsulfonamide) photoacids...
April 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28414148/a-close-collaboration-of-chitosan-with-lipid-colloidal-carriers-for-drug-delivery-applications
#17
REVIEW
Loïc Bugnicourt, Catherine Ladaviere
Chitosan and lipid colloids have separately shown a growing interest in the field of drug delivery applications. Their success is mainly due to their interesting physicochemical behaviors, as well as their biological properties such as bioactivity and biocompatibility. While chitosan is a well-known cationic polysaccharide with the ability to strongly interact with drugs and biological matrices through mainly electrostatic interactions, lipid colloids are carriers particularly recognized for the drug vectorization...
April 14, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28412659/development-of-near-infrared-ratiometric-fluorescent-probe-based-on-cationic-conjugated-polymer-and-cdte-cds-qds-for-label-free-determination-of-glucose-in-human-body-fluids
#18
Mengze Yu, Kunli Zhao, Xiaohua Zhu, Shiyun Tang, Zhou Nie, Yan Huang, Peng Zhao, Shouzhuo Yao
Quantum dots (QDs) have attracted extensive attention in biomedical applications, because of their broad excitation spectra, narrow and symmetric emission peaks etc. Furthermore, near-infrared (NIR) QDs have further advantages including low autofluorescence, good tissue penetration and low phototoxicity. In this work, the electrostatic interaction and fluorescence resonance energy transfer (FRET) between NIR CdTe/CdS QDs and cationic conjugated polymer (CCP) was studied for the first time. Based on the newly discovered phenomena and the result that hydrogen peroxide (H2O2) can efficiently quench the fluorescence of NIR CdTe/CdS QDs, a novel NIR ratiometric fluorescent probe for determination of H2O2 and glucose was developed...
April 1, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28411823/nucleic-acid-controlled-quantum-dots-aggregation-a-label-free-fluorescence-turn-on-strategy-for-alkaline-phosphatase-detection
#19
Zhenzhen Hu, Jian Chen, Yongxin Li, Yan Wang, Qingfeng Zhang, Ejaz Hussain, Meiding Yang, Sohail Anjum Shahzad, Donghong Yu, Cong Yu
Based on the controlled aggregation of quantum dots (QDs), a valid, reliable, and label-free fluorescence turn-on strategy is established for the detection of alkaline phosphatase activity. The aqueous solution of anionic QDs exhibits intense fluorescence. However, the addition of cationic polymer (poly-1) significantly quenched the fluorescence of the QDs via their induced aggregation. While short 3'-phosphorylated DNA (DNA-P) could not be extended by terminal deoxynucleotidyl transferase (TdT) and therefore, fluorescence of the QDs was recovered negligibly...
July 1, 2017: Talanta
https://www.readbyqxmd.com/read/28411548/the-production-of-injectable-hydrazone-crosslinked-gellan-gum-hyaluronan-hydrogels-with-tunable-mechanical-and-physical-properties
#20
Jennika Karvinen, Janne T Koivisto, Ilari Jönkkäri, Minna Kellomäki
Gellan gum (GG) has been proposed for use in tissue engineering (TE) due to its structural and functional similarities with alginate. The most traditional crosslinking methods of GG, ionical and photocrosslinking, have downsides such as loss of stability or phototoxicity, which can limit their use in certain applications. In this study, an alternative hydrazone crosslinking method is introduced. Hydrazone crosslinking is a simple method that produces no toxic reagents or side-products. The method enables the fabrication of injectable hydrogels...
April 7, 2017: Journal of the Mechanical Behavior of Biomedical Materials
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