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electrolyte and acid-base

Minjeong Gu, Keunchang Cho, Seong Ho Kang
The migration behavior of organic fluorescent dyes (i.e., crystal violet, methyl violet base, methyl violet B base, rhodamine 6G, and rhodamine B base) in non-aqueous capillary electrophoresis (NACE) was investigated by focusing on the physicochemical properties of various organic solvents [ethanol, methanol, 2-propanol, dimethylformamide (DMF), and dimethyl sulfoxide (DMSO)] in background electrolyte (BGE). Laser-induced fluorescence (LIF) and UV/Vis detectors were employed to observe both the migration time of organic dyes and the electroosmotic flow (EOF) in NACE, respectively...
May 15, 2018: Journal of Chromatography. A
Ningxiao Yuan, Lu Xu, Bo Xu, Jianhao Zhao, Jianhua Rong
Chitosan derivative-based self-healable hydrogels with enhanced mechanical properties are reported, which were prepared by polymerization of acrylic acid (AAc) in 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) solution. The PAAc/HACC hydrogels exhibit tensile fracture stress as high as 3.31 MPa and a Young's modulus of 2.53 MPa. They can maintain their original shape after 30 repeated compression cycles under various strain conditions, with a compression stress of more than 60 MPa at 99% strain...
August 1, 2018: Carbohydrate Polymers
Thomas Stefan Bronder, Max Philipp Jessing, Arshak Poghossian, Michael Keusgen, Michael J Schöning
Field-effect-based electrolyte-insulator-semiconductor (EIS) sensors were modified with a bilayer of positively charged weak polyelectrolyte (poly(allylamine hydrochloride) (PAH)) and probe single-stranded deoxyribonucleic acid (ssDNA) and are used for the detection of target complementary deoxyribonucleic acid (cDNA) in different test solutions. The sensing mechanism is based on the detection of the intrinsic molecular charge of target cDNA molecules after the hybridization event between cDNA and immobilized probe ssDNA...
May 17, 2018: Analytical Chemistry
Daniel G Beach, Elliott S Kerrin, Krista Thomas, Michael A Quilliam, Pearse McCarron
Polar marine toxins are more challenging to analyze by mass spectrometry-based methods than lipophilic marine toxins, which are now routinely measured in shellfish by multiclass reversed-phase liquid chromatography-tandem mass spectrometry (MS/MS) methods. Capillary electrophoresis (CE)-MS/MS is a technique that is well suited for the analysis of polar marine toxins, and has the potential of providing very high resolution separation. Here, we present a CE-MS/MS method developed, with use of a custom-built interface, for the sensitive multiclass analysis of paralytic shellfish toxins, tetrodotoxins, and domoic acid in seafood...
May 16, 2018: Analytical and Bioanalytical Chemistry
Yonggang Yao, Feng Jiang, Chongyin Yang, Kun Kelvin Fu, John Hayden, Chuan-Fu Lin, Hua Xie, Miaolun Jiao, Chunpeng Yang, Yilin Wang, Shuaiming He, Fujun Xu, Emily Hitz, Tingting Gao, Jiaqi Dai, Wei Luo, Gary Rubloff, Chunsheng Wang, Liangbing Hu
Carbon nanomaterials are desirable candidates for lightweight, highly conductive, and corrosion-resistant current collectors. However, a key obstacle is their weak interconnection between adjacent nanostructures, which renders orders of magnitude lower electrical conductivity and mechanical strength in the bulk assemblies. Here we report an "epitaxial welding" strategy to engineer carbon nanotubes (CNTs) into highly crystalline and interconnected structures. Solution-based polyacrylonitrile was conformally coated on CNTs as "nano-glue" to physically join CNTs into a network, followed by a rapid high temperature annealing (>2800 K, overall ~30 mins) to graphitize the polymer coating into crystalline layers that also bridge the adjacent CNTs to form an interconnected structure...
May 14, 2018: ACS Nano
Tian Lan, Francesca Soavi, Massimo Marcaccio, Pierre-Louis Brunner, Jonathan Sayago, Clara Santato
The n-type organic semiconductor phenyl-C61-butyric acid methyl ester (PCBM), a soluble fullerene derivative well investigated for organic solar cells and transistors, can undergo several successive reversible, diffusion-controlled, one-electron reduction processes. We exploited such processes to shed light on the correlation between electron transfer properties, ionic and electronic transport as well as device performance in ionic liquid (IL)-gated transistors. Two ILs were considered, based on bis(trifluoromethylsulfonyl)imide [TFSI] as the anion and 1-ethyl-3-methylimidazolium [EMIM] or 1-butyl-1-methylpyrrolidinium [PYR14] as the cation...
May 14, 2018: Chemical Communications: Chem Comm
Soile Anja Eliisa Pakkanen, Annemarie de Vries, Marja Riitta Raekallio, Anna Kristina Mykkänen, Mari Johanna Palviainen, Satu Marja Sankari, Outi Maritta Vainio
BACKGROUND: Romifidine, an α-2 adrenoceptor agonist, is a widely-used sedative in equine medicine. Besides the desired sedative and analgesic actions, α-2 adrenoceptor agonists have side effects like alterations of plasma concentrations of glucose and certain stress-related hormones and metabolites in various species. Vatinoxan (previously known as MK-467), in turn, is an antagonist of α-2 adrenoceptors. Because vatinoxan does not cross the blood brain barrier in significant amounts, it has only minor effect on sedation induced by α-2 adrenoceptor agonists...
May 9, 2018: Acta Veterinaria Scandinavica
Barbara Kirchner, Johannes Ingenmey, Sascha Gehrke
Hydrogen is often regarded as fuel of the future and we see an increasing demand for the development of anhydrous proton conducting electrolytes to enable fuel cell operation at elevated temperatures exceeding 120~$^\circ$C. Much attention has been directed at protic ionic liquids (PILs) as promising candidate, but in the search for highly conductive systems the possibility of designing Grotthuss diffusion enabled PILs has been widely overlooked. In this work we explored through ab initio molecular dynamics simulations the mechanics of proton transfer mechanism in the equimolar mixture of \textit{N}-methylimidazole and acetic acid...
May 9, 2018: ChemSusChem
Guo-Xing Zhu, Xulan Xie, Xiaoyun Li, Yuanjun Liu, Xiaoping Shen, Keqiang Xu, Shaowei Chen
FeCo-based materials are promising candidates as efficient, affordable, and sustainable electrocatalysts for oxygen evolution reaction (OER). Herein, a composite based on FeSe2@CoSe2 particles supported on reduced graphene oxide (rGO) was successfully prepared as OER catalyst. In the catalyst, the CoSe2 phase was located on the FeSe2 surface, forming a large number of exposed heterointerfaces with acidic iron sites, due to strong charge interaction between CoSe2 and FeSe2. It is believed that the exposed heterointerfaces act as catalytic active sites for OER via a two-site mechanism, manifesting an overpotential as low as 260 mV to reach the current density of 10 mA cm-2 in 1 M of KOH and excellent stability for at least 6 h, which is superior to CoSe2/rGO, FeSe2/rGO, as well as most of FeNi- and FeCo-based electrocatalysts reported in recent literatures...
May 9, 2018: ACS Applied Materials & Interfaces
Elbaleeq A Gubartallah, Ahmad Makahleh, Joselito P Quirino, Bahruddin Saad
A rapid and green analytical method based on capillary electrophoresis with capacitively coupled contactless conductivity detection (C⁴D) for the determination of eight environmental pollutants, the biogenic amines (putrescine, cadaverine, spermidine, spermine, tyramine, 2-phenylamine, histamine and tryptamine), is described. The separation was achieved under normal polarity mode at 24 °C and 25 kV with a hydrodynamic injection (50 mbar for 5 s) and using a bare fused-silica capillary (95 cm length × 50 µm i...
May 8, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
T T K Nguyen, T N Nguyen, G Anquetin, S Reisberg, V Noël, G Mattana, J Touzeau, F Barbault, M C Pham, B Piro
We investigated an Electrolyte-Gated Organic Field-Effect transistor based on poly(N-alkyldiketopyrrolo-pyrrole dithienylthieno[3,2-b]thiophene) as organic semiconductor whose gate electrode was functionalized by electrografting a functional diazonium salt capable to bind an antibody specific to 2,4-dichlorophenoxyacetic acid (2,4-D), an herbicide well-known to be a soil and water pollutant. Molecular docking computations were performed to design the functional diazonium salt to rationalize the antibody capture on the gate surface...
April 26, 2018: Biosensors & Bioelectronics
Chong Qu, Zibin Liang, Yang Jiao, Bote Zhao, Bingjun Zhu, Dai Dang, Shuge Dai, Yu Chen, Ruqiang Zou, Meilin Liu
Currently, metal-organic frameworks (MOFs) are intensively studied as active materials for electrochemical energy storage applications due to their tunable structure and exceptional porosities. Among them, water stable pillared MOFs with dual ligands have been reported to exhibit high supercapacitor (SC) performance. Herein, the "One-for-All" strategy is applied to synthesize both positive and negative electrodes of a hybrid SC (HSC) from a single pillared MOF. Specifically, Ni-DMOF-TM ([Ni(TMBDC)(DABCO)0...
May 2, 2018: Small
Hui Li, Peng Wen, Adam Hoxie, Chaochao Dun, Shiba Adhikari, Qi Li, Chang Lu, Dominique Itanze, Lin Jiang, David L Carroll, Abdou Lachgar, Yejun Qiu, Scott Geyer
Colloidal semiconductor quantum dots-based (CQD) photocathodes for solar-driven hydrogen evolution have attracted significant attention due to their tunable size, nanostructured morphology, crystalline orientation, and band-gap. Here, we report a thin film heterojunction photocathode composed of organic PEDOT:PSS as a hole transport layer, CdSe CQDs as a semiconductor light absorber, and conformal Pt layer deposited by atomic layer deposition (ALD) serving as both a passivation layer and cocatalyst for hydrogen evolution...
April 30, 2018: ACS Applied Materials & Interfaces
Ziwei Ji, Zhuo Huang, Bowei Chen, Yuhui He, Makusu Tsutsui, Xiangshui Miao
Weak electrolyte transport in nanochannels or nanopores has been actively explored in recent experiments. In this paper, we establish a new electrokinetic model where the ionization balance effect of weak electrolytes is outlined, and performed numerical calculations for H3PO4 concentration-biased nanochannel systems. By considering the roles of local chemical equilibrium in phosphorous acid ionization, the simulation results show quantitative agreement with experimental observations. Based on the model, we predict that enhanced energy harvesting capacity could be accomplished by utilizing weak electrolytes compared to the conventional strong electrolyte approaches in a concentration gradient-based power generating system...
April 30, 2018: Nanotechnology
Genki Saito, Hitoshi Sasaki, Heishichiro Takahashi, Norihito Sakaguchi
Silicon anodes have attracted considerable attention for their use in lithium-ion batteries because of their extremely high theoretical capacity; however, they are prone to extensive volume expansion during lithiation, which causes disintegration and poor cycling stability. In this article, we use two approaches to address this issue, by reducing the size of the Si particles to nanoscale and incorporating them into a carbon composite to help modulate the volume expansion problems. We improve our previous work on the solution-plasma-mediated synthesis of Si nanoparticles (NPs) by adjusting the electrolyte medium to mild buffer solutions rather than strong acids, successfully generating Si-NPs with <10 nm diameters...
April 27, 2018: Nanomaterials
Daxiang Gui, Xing Dai, Zetian Tao, Tao Zheng, Xiangxiang Wang, Mark A Silver, Jie Shu, Lanhua Chen, Yanlong Wang, Tiantian Zhang, Jian Xie, Lin Zou, Yuanhua Xia, Jujia Zhang, Jin Zhang, Ling Zhao, Juan Diwu, Ruhong Zhou, Zhifang Chai, Shuao Wang
Although comprehensive progress has been made in the area of coordination polymer (CP)/metal-organic framework (MOF)-based proton conducting materials over the past decade, searching for a CP/MOF with stable, intrinsic, high anhydrous proton conductivity that can be directly used as a practical electrolyte in an intermediate-temperature proton-exchange membrane fuel cell (PEMFC) assembly for durable power generation remains a substantial challenge. Here, we introduce a new proton conducting CP, (NH4)3[Zr(H2/3PO4)3] (ZrP), which consists of one-dimensional zirconium phosphate anionic chains and fully ordered charge-balancing NH4+ cations...
April 25, 2018: Journal of the American Chemical Society
Hua Xu, Fayez K Ghishan, Pawel R Kiela
The Slc9 family of Na+ /H+ exchangers (NHEs) plays a critical role in electroneutral exchange of Na+ and H+ in the mammalian intestine as well as other absorptive and secretory epithelia of digestive organs. These transport proteins contribute to the transepithelial Na+ and water absorption, intracellular pH and cellular volume regulation as well as the electrolyte, acid-base, and fluid volume homeostasis at the systemic level. They also influence the function of other membrane transport mechanisms, affect cellular proliferation and apoptosis as well as cell migration, adherence to the extracellular matrix, and tissue repair...
March 26, 2018: Comprehensive Physiology
Hyun Jeong Kwak, Oh Kyung Lim, Jae Myung Baik, Youn Yi Jo
Background: To compare the effects of intraoperative infusions of balanced electrolyte solution (BES)-based hydroxyethyl starch (HES) and saline-based albumin on metabolic acidosis and acid/base changes during major abdominal surgery conducted using Stewart's approach. Methods: Forty patients, aged 20-65 years, undergoing major abdominal surgery, were randomly assigned to the HES group (n = 20; received 500 ml of BES-based 6% HES 130/0.4) or the albumin group (n = 20; received 500 ml of normal saline-based 5% albumin)...
April 24, 2018: Korean Journal of Anesthesiology
Laila Moreno Ostertag, Xiao Ling, Katrin F Domke, Sapun H Parekh, Markus Valtiner
The surface density of charged sulfonic acid head groups in a perfluorosulfonic acid (PFSA) proton exchange membrane determines the hydrophilicity of the ionic channels and is thus critical for the structuring and transport of water and protons. The mechanism through which the head group density affects the structuring of water and ions is unknown, largely due to experimental challenges in systematically varying the density in an appropriate model system resembling the ionic channels. Here, we present a model system for PFSA membrane ionic channels using self-assembled monolayers with a tunable surface density of sulfonic acid and methyl groups to tune surface hydrophilicity...
April 23, 2018: Physical Chemistry Chemical Physics: PCCP
Haoran Zhao, Xuexia Yuan, Jiantao Yu, Yishun Huang, Chen Shao, Fan Xiao, Li Lin, Yan Li, Leilei Tian
Functional nucleic acids, that can target cancer cells and realize stimuli-responsive drug-delivery in tumor microenvironment, have been widely applied for anti-cancer chemotherapy. At present, the high cost, unsatisfactory biostability, and complicated fabrication process are the main limits for the development of DNA-based drug-delivery nanocarriers. Here a doxorubicin (Dox)-delivery nanoparticle for tumor-targeting chemotherapy is developed taking advantage of rolling-circle-amplification (RCA) technique, by which a high quantity of functional DNAs can be efficiently collected...
April 20, 2018: ACS Applied Materials & Interfaces
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