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1. Voltage-controlled ion transport and selectivity in a conical nanopore functionalized with pH-tunable polyelectrolyte brushes

Author:
Hsu, Jyh-Ping; Yang, Shu-Tuan; Lin, Chih-Yuan; Tseng, Shiojenn
Source:
Journal of colloid and interface science 2019 v.537 pp. 496-504
ISSN:
0021-9797
Subject:
pH,   etc   ; electrolytes; nanopores; salt concentration;     Show all 4 Subjects
Abstract:
... Chemically functionalized bioinspired nanopores are widely adopted to control the ionic transport for various purposes. A detailed understanding of the underlying mechanisms is not only desirable but also necessary for device design and experimental data interpretation. Here, the conductance and the ion selectivity of a conical nanopore surface modified by a polyelectrolyte (PE) layer are studied ...
DOI:
10.1016/j.jcis.2018.11.046

2. Ion transport in a pH-regulated conical nanopore filled with a power-law fluid

Author:
Hsu, Jyh-Ping; Chu, Yu-You; Lin, Chih-Yuan; Tseng, Shiojenn
Source:
Journal of colloid and interface science 2019 v.537 pp. 358-365
ISSN:
0021-9797
Subject:
pH,   etc   ; isoelectric point; nanopores; salt concentration; viscosity;     Show all 5 Subjects
Abstract:
... Extending previous electrokinetic analyses based on a Newtonian fluid to power-law fluids, we investigate the behaviors of the ion current rectification (ICR) and the ion selectivity S of a conical nanopore having a pH-regulated surface. The bulk salt concentration Cbulk, the solution pH, and the power-law index n are examined in detail for their influences on these behaviors. We show that the ICR ...
DOI:
10.1016/j.jcis.2018.11.020

3. π-π stacking interaction is a key factor for the stability of GH11 xylanases at low pH

Author:
Ge, Hui-Hua; Qiu, Yue; Yi, Zhi-Wei; Zeng, Run-Ying; Zhang, Guang-Ya
Source:
International journal of biological macromolecules 2019 v.124 pp. 895-902
ISSN:
0141-8130
Subject:
pH,   etc   ; amino acids; engineering; equations; mutation; xylanases;     Show all 6 Subjects
Abstract:
... Acidic xylanases possess the unique features necessary for the tolerance of acidic environments, which may have great potentials for industrial purposes. However, factors controlling the pH-dependent stability of xylanases are only partially known. Here we proposed a residue interaction networks based method to analyze the differences of residue interactions between 6 pairs of experimentally verif ...
DOI:
10.1016/j.ijbiomac.2018.11.282

4. Paper-based ion-selective optodes for continuous sensing: Reversible potassium ion monitoring

Author:
Kassal, Petar; Sigurnjak, Marija; Steinberg, Ivana Murković
Source:
Talanta 2019 v.193 pp. 51-55
ISSN:
0039-9140
Subject:
pH,   etc   ; lipophilicity; monitoring; paper; potassium; reflectometry; valinomycin;     Show all 7 Subjects
Abstract:
... A simple, low-cost paper-based potassium ion-selective optode that exhibits fully reversible sensing properties is presented. A classic optode formulation consisting of valinomycin as the ionophore and a lipophilic pH indicator has been successfully transferred to a paper substrate and characterised in a flow-through cell with reflectometric optical detection. The optode exhibits high repeatabilit ...
DOI:
10.1016/j.talanta.2018.09.031

5. Influence of framework and interlayer on the colloidal stability of design swelling high-charged micas

Author:
Osuna, Francisco J.; Cota, Agustín; Fernández, Mariela A.; Pavón, Esperanza; Torres Sánchez, Rosa M.; Alba, María D.
Source:
Colloids and surfaces 2019 v.561 pp. 32-38
ISSN:
0927-7757
Subject:
pH,   etc   ; cations; colloids; mica; zeta potential;     Show all 5 Subjects
Abstract:
... Stability of colloidal clay minerals dispersion of fundamental in many industrial processes. Therefore, surface charge of the synthetic swelling high-charged mica family, Na-Mica-n (n = 2 or 4, n is the total layer charge) were investigated to study its colloidal dispersion stability as a function of the framework and interlayer space composition. Na-Mica-n (n = 2 or 4) micas were synthesized and ...
DOI:
10.1016/j.colsurfa.2018.09.086

6. Process optimization of chiral extraction of 2,3-diphenylpropionic acid by experiment and simulation

Author:
Wang, Wanru; Xu, Weifeng; Dai, Guilin; Zhang, Panliang; Tang, Kewen
Source:
Process biochemistry 2019 v.76 pp. 178-186
ISSN:
1359-5113
Subject:
pH,   etc   ; enantiomers; models; separators; solvents; thermodynamics;     Show all 6 Subjects
Abstract:
... This paper reports the process optimization of chiral extraction of 2,3-diphenylpropionic acid (2,3-2-PPA) enantiomers by experiment and simulation in centrifugal contactor separators. An efficient extraction system was obtained firstly through single-stage extraction experiments and single-stage extraction model, where sulfobutylether-β-cyclodextrin (SBE-β-CD) and 1,2-dichlorethane were selected ...
DOI:
10.1016/j.procbio.2018.10.009

7. Extent of adaptation is not limited by unpredictability of the environment in laboratory populations of Escherichia coli

Author:
Karve, Shraddha M.; Bhave, Devika; Dey, Sutirth
Source:
Journal of evolutionary biology 2018 v.31 no.9 pp. 1420-1426
ISSN:
1010-061X
Subject:
pH,   etc   ; Escherichia coli; temperature;     Show all 3 Subjects
Abstract:
... Environmental variability is on the rise in different parts of the earth, and the survival of many species depends on how well they cope with these fluctuations. Our current understanding of how organisms adapt to unpredictably fluctuating environments is almost entirely based on studies that investigate fluctuations among different values of a single environmental stressor such as temperature or ...
DOI:
10.1111/jeb.13338

8. Elucidation of chromatographic peak shifts in complex samples using a chemometrical approach

Author:
Sousa, Pedro F. M.; de Waard, Angela; Åberg, K. Magnus
Source:
Analytical and bioanalytical chemistry 2018 v.410 no.21 pp. 5229-5235
ISSN:
1618-2642
Subject:
pH,   etc   ; algorithms; chromatography; temperature;     Show all 4 Subjects
Abstract:
... Chromatographic retention time peak shifts between consecutive analyses is a well-known fact yet not fully understood. Algorithms have been developed to align peaks between runs, but with no specific studies considering the causes of peak shifts. Here, designed experiments reveal chromatographic shift patterns for a complex peptide mixture that are attributable to the temperature and pH of the mob ...
DOI:
10.1007/s00216-018-1173-9

9. Efficient fabrication of reversible pH-induced carboxymethyl chitosan nanoparticles for antitumor drug delivery under weakly acidic microenvironment

Author:
Li, Tao; Yang, Jin; Liu, Rong; Yi, Yang; Huang, Mengtian; Wu, Yang; Tu, Hu; Zhang, Li
Source:
International journal of biological macromolecules 2019 v.126 pp. 68-73
ISSN:
0141-8130
Subject:
pH,   etc   ; aqueous solutions; chitosan; colloids; doxorubicin; encapsulation; nanoparticles; neoplasms; therapeutics;     Show all 9 Subjects
Abstract:
... Searching for the carrier systems for drug controlled release under weakly acidic condition related to tumor environment has attracted a tremendous level of attention. In this study, amphiphilic carboxymethyl chitosan (CMC) was employed to fabricate nanoparticles (NPs) with an efficient and simple method by adjusting the pH values of CMC aqueous solutions. The prepared NPs could not only capture t ...
DOI:
10.1016/j.ijbiomac.2018.12.178

10. Preparation of quaternary amine-grafted organosolv lignin biosorbent and its application in the treatment of hexavalent chromium polluted water

Author:
Wang, Zhen; Huang, Wenxiu; Bin, Pingping; Zhang, Xuan; Yang, Guihua
Source:
International journal of biological macromolecules 2019 v.126 pp. 1014-1022
ISSN:
0141-8130
Subject:
pH,   etc   ; adsorbents; adsorption; aqueous solutions; biosorbents; chromium; formaldehyde; lignin;     Show all 8 Subjects
Abstract:
... A novel cationic biosorbent was synthesized by grafting organosolv lignin with GT (also named (2-hydrazinyl-2-oxoethyl)-trimethylazanium chloride, abbreviated as GT) and formaldehyde in an aqueous solution by an eco-friendly way (named QA-g-OL). QA-g-OL was employed as biosorbent to remediate hexavalent chromium polluted water. Research found Cr(VI) removal is a pH-dependence process. It was also ...
DOI:
10.1016/j.ijbiomac.2018.12.087

11. Effect of polymer concentration and solution pH on viscosity affecting integrity of a polysaccharide coat of compression coated tablets

Author:
Sa, Biswanath; Mukherjee, Sudipta; Roy, Sanjit Kr
Source:
International journal of biological macromolecules 2019 v.125 pp. 922-930
ISSN:
0141-8130
Subject:
pH,   etc   ; drugs; enzymes; locust bean gum; polymers; viscosity;     Show all 6 Subjects
Abstract:
... Tablets, compression coated with certain polysaccharides and intended for colon delivery, retain the integrity of the coat for an initial period of about 6 h (lag period) beyond which (post-lag period) the coat is degraded by colonic enzymes to induce drug release. This work was undertaken to investigate the factors which influence the integrity of the coat during the lag period. Core tablets cont ...
DOI:
10.1016/j.ijbiomac.2018.12.101

12. Folding of poly-amino acids and intrinsically disordered proteins in overcrowded milieu induced by pH change

Author:
Fonin, Alexander V.; Stepanenko, Olga V.; Sitdikova, Asiia K.; Antifeeva, Iuliia A.; Kostyleva, Elena I.; Polyanichko, Alexander M.; Karasev, Maksim M.; Silonov, Sergey A.; Povarova, Olga I.; Kuznetsova, Irina M.; Uversky, Vladimir N.; Turoverov, Konstantin К.
Source:
International journal of biological macromolecules 2019 v.125 pp. 244-255
ISSN:
0141-8130
Subject:
pH,   etc   ; acids; amino acids; histones; organelles; phase transition;     Show all 6 Subjects
Abstract:
... pH-induced structural changes of the synthetic homopolypeptides poly-E, poly-K, poly-R, and intrinsically disordered proteins (IDPs) prothymosin α (ProTα) and linker histone H1, in concentrated PEG solutions simulating macromolecular crowding conditions within the membrane-less organelles, were characterized. The conformational transitions of the studied poly-amino acids in the concentrated PEG so ...
DOI:
10.1016/j.ijbiomac.2018.12.038

13. Study of the complex coacervation mechanism between the lysing enzyme from T. harzianum and polyallylamine hydrochloride

Author:
Bey, Houda; Gtari, Wala; Aschi, Adel
Source:
International journal of biological macromolecules 2019 v.124 pp. 780-787
ISSN:
0141-8130
Subject:
pH,   etc   ; droplets; light scattering; mixing; polyallylamines; temperature; zeta potential;     Show all 7 Subjects
Abstract:
... Complex coacervation was achieved by mixing the lysing enzyme from T. harzianum (LYS) with polyallylamine hydrochloride (PAH). We show in this work that the study electrostatic complexes conformation can lead to the formation of dense complexes. We systematically investigated the effects of pH and the mass ratio on the structure and properties of the complex. The different transition phases (pHc, ...
DOI:
10.1016/j.ijbiomac.2018.11.266

14. Two distinct aggregation pathways in transthyretin misfolding and amyloid formation Proteins and proteomics

Author:
Dasari, Anvesh K.R.; Hung, Ivan; Gan, Zhehong; Lim, Kwang Hun
Source:
Biochimica et biophysica acta 2019 v.1867 no.3 pp. 344-349
ISSN:
1570-9639
Subject:
pH,   etc   ; amyloid; chemical structure; mutation; nuclear magnetic resonance spectroscopy; prealbumin;     Show all 6 Subjects
Abstract:
... Misfolding and amyloid formation of transthyretin (TTR) is implicated in numerous degenerative diseases. TTR misfolding is greatly accelerated under acidic conditions, and thus most of the mechanistic studies of TTR amyloid formation have been conducted at various acidic pH values (2–5). In this study, we report the effect of pH on TTR misfolding pathways and amyloid structures. Our combined solut ...
DOI:
10.1016/j.bbapap.2018.10.013

15. Visual determination of malachite green in sea fish samples

Author:
Gavrilenko, Nataliya A.; Volgina, Tatyana N.; Pugachev, Evgeniy V.; Gavrilenko, Mikhail A.
Source:
Food chemistry 2019 v.274 pp. 242-245
ISSN:
0308-8146
Subject:
pH,   etc   ; calibration; color; ions; malachite green; marine fish; polymethylmethacrylate; temperature;     Show all 8 Subjects
Abstract:
... Polymethylmethacrylate matrix has been developed as an analytical device for visual and spectrophotometric determination of malachite green. Based on the studied effects of different pH levels, temperature, contact time and diverse ions, optimum analysis conditions have been established. For malachite green, the calibration graph was linear in the range of 0.5–30 mg·L⁻¹ in the samples with the det ...
DOI:
10.1016/j.foodchem.2018.08.139

16. Preparation of NiAl-LDH/Polypyrrole composites for uranium(VI) extraction from simulated seawater

Author:
Zhong, Chongna; Su, Shouzheng; Xu, Li; Liu, Qi; Zhang, Hongsen; Yang, Piaoping; Zhang, Milin; Bai, Xuefeng; Wang, Jun
Source:
Colloids and surfaces 2019 v.562 pp. 329-335
ISSN:
0927-7757
Subject:
pH,   etc   ; adsorption; colloids; endothermy; models; seawater; sorption isotherms; temperature; uranium;     Show all 9 Subjects
Abstract:
... In this work, NiAl-LDH/Polypyrrole (NiAl-LDH/PPy) was synthesized by a simple method for the adsorption of uranium(VI) (U(VI)) from simulated seawater. The parameters studied contained pH, contact time, initial concentration and temperatures. The kinetic parameters showed that it could be well consistent with pseudo-second-order model. Langmuir and Freundlich isotherm models were used to describe ...
DOI:
10.1016/j.colsurfa.2018.11.029

17. Transformation of bisphenol AF and bisphenol S by permanganate in the absence/presence of iodide: Kinetics and products

Author:
Li, Juan; Jiang, Jin; Pang, Su–Yan; Gao, Yuan; Sun, Shaofang; Wang, Zhen; Wang, Panxin; Wang, Lihong; Zhou, Yang
Source:
Chemosphere 2019 v.217 pp. 402-410
ISSN:
0045-6535
Subject:
pH,   etc   ; bisphenol S; hydroxylation; iodides; kinetics; manganese; oxidation; toxicity;     Show all 8 Subjects
Abstract:
... Recent studies have reported that permanganate (Mn(VII)) shows a good performance in treatment of phenolic compounds, and the presence of iodide (I−) may display a great impact on Mn(VII) oxidation with the formation of toxic iodinated aromatic products. In this work, transformation of bisphenol AF (BPAF) and bisphenol S (BPS) by Mn(VII) in the absence or presence of I− was studied. Mn(VII) showed ...
DOI:
10.1016/j.chemosphere.2018.11.011

18. Co2P@NiCo2O4 bi-functional electrocatalyst with low overpotential for water splitting in wide range pH electrolytes

Author:
Liu, Ying; Yang, Fei; Qin, Wei; Yang, Guowei
Source:
Journal of colloid and interface science 2019 v.534 pp. 55-63
ISSN:
0021-9797
Subject:
pH,   etc   ; catalysts; electrochemistry; electrolytes; hydrogen production; hydroxides; oxides; oxygen production;     Show all 8 Subjects
Abstract:
... The Co2P@NiCo2O4 bi-functional electrocatalyst was fabricated for hydrogen evolution reaction and oxygen evolution reaction in acidic, neutral and alkaline media. The Co2P@NiCo2O4 in alkaline media exhibites an extremely low overpotential of 170 mV in oxygen evolution to achieve a current density of 10 mA cm⁻² and produces stable water splitting nearly 30 h. The anchored-Co2P can enhance the elect ...
DOI:
10.1016/j.jcis.2018.09.017

19. Dissolution behavior and conformation change of chitosan in concentrated chitosan hydrochloric acid solution and comparison with dilute and semidilute solutions

Author:
Wu, Jianfeng; Zhang, Liyan
Source:
International journal of biological macromolecules 2019 v.121 pp. 1101-1108
ISSN:
0141-8130
Subject:
pH,   etc   ; chitosan; chlorides; hydrochloric acid; hydrophobicity; turbidity; viscosity;     Show all 7 Subjects
Abstract:
... Viscosity, pH and electrolytic conductivity of dilute, semidilute and concentrated chitosan solution with hydrochloric acid adding were compared and the change in conformation of chitosan in concentrated solution was discussed. The dissolution behavior of chitosan in concentrated chitosan hydrochloric acid solution was investigated through determination of solution turbidity, microstate and size o ...
DOI:
10.1016/j.ijbiomac.2018.10.128

20. A laccase-catalysed synthesis of triaminated cyclohexa-2,4-dienones from catechol

Author:
Wellington, Kevin W.; Govindjee, Varsha P.; Steenkamp, Paul
Source:
Journal of catalysis 2018 v.368 pp. 306-314
ISSN:
0021-9517
Subject:
pH,   etc   ; air; catechol; ethanol; laccase;     Show all 5 Subjects
Abstract:
... A commercial laccase, Suberase® from Novozymes, catalyses the synthesis of triaminated cyclohexa-2,4-dienones and a methylbenzene-1,2-diol derivative. The primary amine (analine) and the catechol was reacted under mild conditions (40 °C) in a reaction vessel open to air in the presence of Suberase® and a co-solvent (DMF) at pH 6.0. This reaction was also conducted using an environmentally friendly ...
DOI:
10.1016/j.jcat.2018.10.014