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acid base strong ion

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https://www.readbyqxmd.com/read/28433060/enhanced-photoresponsive-polyethyleneimine-citric-acid-co-carbonized-dots-for-facile-and-selective-sensing-and-intracellular-imaging-of-cobalt-ions-at-physiologic-ph
#1
Wen-Sheng Zou, Qing-Chun Zhao, Jun Zhang, Xiao-Ming Chen, Xiu-Fang Wang, Lin Zhao, Shao-Hua Chen, Ya-Qin Wang
Whether as an important biological element or as a radioactive source/medicine, the monitoring of trace levels of cobalt ions (Co) has become a non-negligible factor for human health and green environment. Current technologies for the detection of Co are cost-expensive and time-consuming, and require cumbersome sample pretreatment process. Herein a novel sensing platform has been developed for Co detection based on the quenching of the enhanced fluorescence signal of polyamine functionalized C-dots. Amine groups at the surface of the C-dots can capture Zn(2+)/Cd(2+) to form coordination compound, which can inhibit the photoinduced electron transfer pathways of C-dots and then induce the fluorescence enhancement of the C-dots by ∼80% margin...
June 1, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28426209/channel-assisted-proton-conduction-behavior-in-hydroxyl-rich-lanthanide-based-magnetic-metal-organic-frameworks
#2
Soumava Biswas, Jayita Chakraborty, Vijay Singh Parmar, Siba Prasad Bera, Nirmal Ganguli, Sanjit Konar
Two new lanthanide-based 3D metal-organic frameworks (MOFs), {[Ln(L)(Ox)(H2O)]n·xH2O} [Ln = Gd(3+) and x = 3 (1) and Dy(3+) and x = 1.5 (2); H2L = mucic acid; OxH2 = oxalic acid] showing interesting magnetic properties and channel-mediated proton conduction behavior, are presented here. Single-crystal X-ray structure analysis shows that, in complex 1, the overall structure originates from the mucate-bridged gadolinium-based rectangular metallocycles. The packing view reveals the presence the two types of hydrophilic 1D channels filled with lattice water molecules, which are strongly hydrogen-bonded with coordinated water along the a and b axes, whereas for complex 2, the 3D framework originates from a carboxylate-bridged dysprosium-based criss-cross-type secondary building block...
April 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28425293/cosensitized-porphyrin-system-for-high-performance-solar-cells-with-tof-sims-analysis
#3
Wenjun Wu, Huaide Xiang, Wei Fan, Jinglin Wang, Haifeng Wang, Xin Hua, Zhaohui Wang, Yi-Tao Long, He Tian, Wei-Hong Zhu
Up to date, development of organic sensitizers has been predominately focused on light harvesting, HOMO and LUMO energy levels, and electron transferring process. In contrast, their adsorption mode as well as dynamic loading behaviour onto nanoporous TiO2 is rarely considered. Herein we have employed the time of flight secondary ion mass spectrometry (TOF-SIMS) to take insight into the competitive dye adsorption mode and kinetics in cosensitized porphyrin system. Using the novel porphyrin dye FW-1 and D-A-π-A featured dye WS-5, the different bond-breaking mode in TOF-SIMS and dynamic dye-loading amount during the coadsorption process are well compared with two different anchoring groups such as benzoic acid and cyanoacrylic acid...
April 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28420042/determination-of-reference-intervals-of-acid-base-parameters-in-clinically-healthy-dogs
#4
Ivana Vanova-Uhrikova, Leona Rauserova-Lexmaulova, Kristina Rehakova, Peter Scheer, Jaroslav Doubek
OBJECTIVE: To establish reference intervals for traditionally- and Stewart's approach-determined acid-base parameters in a population of clinically healthy dogs. DESIGN: Prospective study (June 2011-September 2012). SETTING: Veterinary teaching hospital. ANIMALS: Two hundred twenty-four client-owned, clinically healthy dogs. INTERVENTIONS: Blood was collected from the jugular vein and the dorsal pedal artery...
April 18, 2017: Journal of Veterinary Emergency and Critical Care
https://www.readbyqxmd.com/read/28414912/observation-of-photovoltaic-action-from-photoacid-modified-nafion-due-to-light-driven-ion-transport
#5
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/28407573/assessment-of-mobility-and-bioavailability-of-mercury-compounds-in-sewage-sludge-and-composts
#6
Beata Janowska, Kazimierz Szymański, Robert Sidełko, Izabela Siebielska, Bartosz Walendzik
Content of heavy metals, including mercury, determines the method of management and disposal of sewage sludge. Excessive concentration of mercury in composts used as organic fertilizer may lead to accumulation of this element in soil and plant material. Fractionation of mercury in sewage sludge and composts provides a better understanding of the extent of mobility and bioavailability of the different mercury species and helps in more informed decision making on the application of sludge for agricultural purposes...
April 10, 2017: Environmental Research
https://www.readbyqxmd.com/read/28406612/sulfonic-groups-originated-dual-functional-interlayer-for-high-performance-lithium-sulfur-battery
#7
Yang Lu, Sui Gu, Jing Guo, Kun Rui, Chunhua Chen, Sanpei Zhang, Jun Jin, Jianhua Yang, Zhaoyin Wen
Lithium sulfur battery is one of the most prospective chemistries in secondary energy storage field due to its high energy density and high theoretical capacity. However, the dissolution of polysulfides in liquid electrolytes causes shuttle effect and the rapid decay of lithium sulfur battery has greatly hindered its practical application. Herein, combination of sulfonated reduced graphene oxide (SRGO) interlayer on the separator is adopted to suppress the shuttle effect. We speculate that this SRGO layer plays as two roles: physically blocking the migration of polysulfide as ion selective layer and anchoring lithium polysulfide by the electronegative sulfonic group...
April 13, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28388073/strongly-circularly-polarized-emission-from-water-soluble-eu-iii-and-tb-iii-based-complexes-a-structural-and-spectroscopic-study
#8
Marco Leonzio, Andrea Melchior, Georgina Faura, Marilena Tolazzi, Francesco Zinna, Lorenzo Di Bari, Fabio Piccinelli
Water-soluble Eu(III) and Tb(III) complexes with N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane-N,N'-diacetic acid (H2bpcd) have been synthesized and characterized in their racemic and enantiopure forms. The ligand has been designed to bind Ln(III) ions, providing a dissymmetric environment able to solicit strong chiroptical features while at the same time leaving a few coordination sites available for engaging further ancillary ligands. Potentiometric studies show that Ln(III) complexes have a relatively good stability and that at pH 7 the [Ln(bpcd)](+) species is largely dominant...
April 7, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28380062/different-effects-of-fluid-loading-with-saline-gelatine-hydroxyethyl-starch-or-albumin-solutions-on-acid-base-status-in-the-critically-ill
#9
Angélique M E Spoelstra-de Man, Annemieke Smorenberg, A B Johan Groeneveld
INTRODUCTION: Fluid administration in critically ill patients may affect acid-base balance. However, the effect of the fluid type used for resuscitation on acid-base balance remains controversial. METHODS: We studied the effect of fluid resuscitation of normal saline and the colloids gelatine 4%, hydroxyethyl starch (HES) 6%, and albumin 5% on acid-base balance in 115 clinically hypovolemic critically ill patients during a 90 minute filling pressure-guided fluid challenge by a post-hoc analysis of a prospective randomized clinical trial...
2017: PloS One
https://www.readbyqxmd.com/read/28379006/gadolinium-complex-for-the-catch-and-release-of-phosphate-from-water
#10
Sarah M Harris, Jamie T Nguyen, Sylvie L Pailloux, Jarrett P Mansergh, Mark J Dresel, Tran B Swanholm, Tuo Gao, Valérie C Pierre
The ability of complexes of hard and labile metal ions with one or more open coordination sites to capture phosphates with high affinity and selectivity directly in water at neutral pH and release them under acidic conditions is evaluated with Gadolinium- 2,2',2''-(((nitrilotris(ethane-2,1-diyl))tris(azanediyl))tris(carbonyl))tris(4-oxo-4H-pyran-3-olate) (Gd-TREN-MAM). This model lanthanide complex has two open coordination sites that, at neutral pH, are filled with water molecules. In water at neutral pH, Gd-TREN-MAM binds phosphate with high affinity (Ka = 1...
April 5, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28374993/removable-backbone-modification-method-for-the-chemical-synthesis-of-membrane-proteins
#11
Jia-Bin Li, Shan Tang, Ji-Shen Zheng, Chang-Lin Tian, Lei Liu
Chemical synthesis can produce water-soluble globular proteins bearing specifically designed modifications. These synthetic molecules have been used to study the biological functions of proteins and to improve the pharmacological properties of protein drugs. However, the above advances notwithstanding, membrane proteins (MPs), which comprise 20-30% of all proteins in the proteomes of most eukaryotic cells, remain elusive with regard to chemical synthesis. This difficulty stems from the strong hydrophobic character of MPs, which can cause considerable handling issues during ligation, purification, and characterization steps...
April 4, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28368405/connexin-43-channels-are-a-pathway-for-discharging-lactate-from-glycolytic-pancreatic-ductal-adenocarcinoma-cells
#12
T H Dovmark, M Saccomano, A Hulikova, F Alves, P Swietach
Glycolytic cancer cells produce large quantities of lactate that must be removed to sustain metabolism in the absence of oxidative phosphorylation. The only venting mechanism described to do this at an adequate rate is H(+)-coupled lactate efflux on monocarboxylate transporters (MCTs). Outward MCT activity is, however, thermodynamically inhibited by extracellular acidity, a hallmark of solid tumours. This inhibition would feedback unfavourably on metabolism and growth, raising the possibility that other venting mechanisms become important in under-perfused tumours...
April 3, 2017: Oncogene
https://www.readbyqxmd.com/read/28363419/the-importance-of-ion-pairing-in-peptide-purification-by-reversed-phase-liquid-chromatography
#13
Dennis Åsberg, Annika Langborg Weinmann, Tomas Leek, Richard J Lewis, Magnus Klarqvist, Marek Leśko, Krzysztof Kaczmarski, Jörgen Samuelsson, Torgny Fornstedt
The adsorption mechanism for three peptides was studied under overloaded conditions through adsorption isotherm measurements in the presence of an ion-pairing reagent, trifluoroacetic acid (TFA), on an end-capped C18-bonded stationary phase. The overall aim of the study was to obtain a better understanding of how the acetonitrile and the TFA fractions in the eluent affected the overloaded elution profiles and the selectivity between peptides using mechanistic modelling and multivariate design of experiments...
March 21, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28362083/ultrasensitive-and-selective-sensing-of-selenium-using-nitrogen-rich-ligand-interfaced-carbon-quantum-dots
#14
Pooja Devi, Anupma Thakur, Shweta Chopra, Navneet Kaur, Praveen Kumar, Narinder Singh, Mahesh Kumar, Sonnada Math Shivaprasad, Manoj K Nayak
This work reports a label-free, ultrasensitive, and selective optical chemosensory system for trace level detection of selenite (SeO3(2-)), the most toxic form of selenium, in water. The probe, i.e., carbon quantum dots (CQDs), is designed from citric acid by means of pyrolysis and is interfaced with a newly synthesized nitrogen-rich ligand to create a selective sensor platform (functionalized CQDs, fCQDs) for selenite in a water matrix. Spectral (NMR, UV-vis, photoluminescence, Raman, and Fourier transform infrared analyses) and structural (high-resolution transmission electron microscopy) characteristics of the designed new probe were investigated...
April 6, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28345925/metal-insertion-in-a-methylamine-functionalized-zirconium-metal-organic-framework-for-enhanced-carbon-dioxide-capture
#15
A Paulina Gómora-Figueroa, Jarad A Mason, Miguel I Gonzalez, Eric D Bloch, Katie R Meihaus
The reaction of ZrCl4 with 2',3',5',6'-tetramethylamino-p-terphenyl-4,4″-dicarboxylic acid (H2tpdc-4CH2NH2·3HCl) in the presence of NaF affords Zr6O4(OH)2.1F1.9(tpdc-4CH2NH2·3HCl)6 (1), which is a new member of the Zr6O4(OH)4(dicarboxylate linker)12 or UiO-68 family, and exhibits high porosity with BET and Langmuir surface areas of 1910 m(2)/g and 2220 m(2)/g, respectively. Remarkably, fluoride ion incorporation in the zirconium clusters results in increased thermal stability, marking the first example of enhancement in the stability of a UiO framework by this defect-restoration approach...
March 27, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28335258/nanostructures-derived-from-starch-and-chitosan-for-fluorescence-bio-imaging
#16
Yinxue Zu, Jingran Bi, Huiping Yan, Haitao Wang, Yukun Song, Bei-Wei Zhu, Mingqian Tan
Fluorescent nanostructures (NSs) derived from polysaccharides have drawn great attention as novel fluorescent probes for potential bio-imaging applications. Herein, we reported a facile alkali-assisted hydrothermal method to fabricate polysaccharide NSs using starch and chitosan as raw materials. Transmission electron microscopy (TEM) demonstrated that the average particle sizes are 14 nm and 75 nm for starch and chitosan NSs, respectively. Fourier transform infrared (FT-IR) spectroscopy analysis showed that there are a large number of hydroxyl or amino groups on the surface of these polysaccharide-based NSs...
July 5, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28318906/analysis-of-molecular-mechanisms-of-atp-synthesis-from-the-standpoint-of-the-principle-of-electrical-neutrality
#17
REVIEW
Sunil Nath
Theories of biological energy coupling in oxidative phosphorylation (OX PHOS) and photophosphorylation (PHOTO PHOS) are reviewed and applied to ATP synthesis by an experimental system containing purified ATP synthase reconstituted into liposomes. The theories are critically evaluated from the standpoint of the principle of electrical neutrality. It is shown that the obligatory requirement to maintain overall electroneutrality of bulk aqueous phases imposes strong constraints on possible theories of energy coupling and molecular mechanisms of ATP synthesis...
March 8, 2017: Biophysical Chemistry
https://www.readbyqxmd.com/read/28300265/catalytic-routes-to-fuels-from-c1-and-oxygenate-molecules
#18
Shuai Wang, Iker Agirrezabal-Telleria, Aditya Bhan, Dante Simonetti, Kazuhiro Takanabe, Enrique Iglesia
This account illustrates concepts in chemical kinetics underpinned by the formalism of transition state theory using catalytic processes that enable the synthesis of molecules suitable as fuels from C1 and oxygenate reactants. Such feedstocks provide an essential bridge towards a carbon-free energy future, but their volatility and low energy density require the formation of new C-C bonds and the removal of oxygen. These transformations are described here through recent advances in our understanding of the mechanisms and site requirements in catalysis by surfaces, with emphasis on enabling concepts that tackle ubiquitous reactivity and selectivity challenges...
March 16, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28299927/supramolecular-hydrogels-based-on-dna-self-assembly
#19
Yu Shao, Haoyang Jia, Tianyang Cao, Dongsheng Liu
Extracellular matrix (ECM) provides essential supports three dimensionally to the cells in living organs, including mechanical support and signal, nutrition, oxygen, and waste transportation. Thus, using hydrogels to mimic its function has attracted much attention in recent years, especially in tissue engineering, cell biology, and drug screening. However, a hydrogel system that can merit all parameters of the natural ECM is still a challenge. In the past decade, deoxyribonucleic acid (DNA) has arisen as an outstanding building material for the hydrogels, as it has unique properties compared to most synthetic or natural polymers, such as sequence designability, precise recognition, structural rigidity, and minimal toxicity...
March 16, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28293954/an-all-organic-proton-battery
#20
Rikard Emanuelsson, Mia Sterby, Maria Strømme, Martin Sjödin
Rechargeable batteries that use organic matter as the capacity-carrying material have previously been considered a technology for the future. Earlier batteries in which both the anode and cathode consisted of organic material required significant amounts of conductive additives and were often based on metal-ion electrolytes containing Li(+) or Na(+). However, we have used conducting poly(3,4-ethylenedioxythiophene) (PEDOT), functionalized with anthraquinone (PEDOT-AQ) or benzonquinone (PEDOT-BQ) pendant groups as the negative and positive electrode materials, respectively, to make an all-organic proton battery devoid of metals...
March 28, 2017: Journal of the American Chemical Society
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