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acid base strong ion

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https://www.readbyqxmd.com/read/28814306/blood-acid-base-status-in-impala-aepyceros-melampus-immobilised-and-maintained-under-total-intravenous-anaesthesia-using-two-different-drug-protocols
#1
Gareth E Zeiler, Leith C R Meyer
BACKGROUND: In mammals, homeostasis and survival are dependent on effective trans-membrane movement of ions and enzyme function, which are labile to extreme acid-base changes, but operate efficiently within a narrow regulated pH range. Research in patients demonstrating a pH shifts outside the narrow regulated range decreased the cardiac output and systemic vascular resistance and altered the oxygen binding to haemoglobin. These cardiopulmonary observations may be applicable to the risks associated with anaesthesia and performance of wildlife ungulates on game farms...
August 16, 2017: BMC Veterinary Research
https://www.readbyqxmd.com/read/28810120/aqueous-solvation-of-ammonia-and-ammonium-probing-hydrogen-bond-motifs-with-ft-ir-and-soft-x-ray-spectroscopy
#2
Maria Ekimova, Wilson Quevedo, Lukasz Szyc, Marcella Iannuzzi, Philippe Wernet, Michael Odelius, Erik T J Nibbering
In a multi-facetted investigation combining local soft-x-ray and vibrational spectroscopic probes with ab initio molecular dynamics simulations, hydrogen-bond interactions of two key principal amine compounds in aqueous solution, ammonia (NH3) and ammonium ion (NH4+), are quantitatively assessed in terms of electronic structure, solvation structure, and dynamics. From the x-ray measurements and from the complementary determination of the IR-active hydrogen stretching and bending modes of NH3 and NH4+ in aqueous solution, the picture emerges of a comparatively strongly hydrogen-bonded NH4+ ion via N-H donating interactions, whereas NH3 has a strong accepting hydrogen bond with one water molecule at the nitrogen lone pair but only weak N-H donating hydrogen bonds...
August 15, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28802525/layered-double-hydroxides-based-ion-exchange-extraction-for-high-sensitive-analysis-of-non-steroidal-anti-inflammatory-drugs
#3
Wei Zhou, Chenlu Wang, Yikun Liu, Wenpeng Zhang, Zilin Chen
Layered double hydroxides (LDHs) are ideal sorbents for solid phase extraction (SPE) because of the excellent ion exchange capacity and high specific surface area. However, difficult elution of the analytes from the LDHs is a problem due to the strong ionic interaction between anions and LDHs. High concentrated NaOH solution is employed to elute the sample, but it not suitable for analyzing by HPLC. To solve this problem, a simple acid-base neutralization method was proposed after elution, and then the neutral samples were directly injected to HPLC for analysis...
July 15, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28796517/computational-and-experimental-investigation-of-the-detection-of-ho2-radical-and-the-products-of-its-reaction-with-cyclohexene-ozonolysis-derived-ro2-radicals-by-an-iodide-based-chemical-ionization-mass-spectrometer
#4
Siddharth Iyer, Xucheng He, Noora Hyttinen, Theo Kurtén, Matti P Rissanen
The HO2 radical is an important atmospheric molecule that can potentially influence the termination of autoxidation processes of volatile organic compounds (VOCs) that lead to the formation of highly oxygenated multifunctional compounds (HOMs). In this work, we demonstrate the direct detection of the HO2 radical using an iodide-based chemical ionization mass spectrometer (iodide-CIMS). Expanding on the previously established correlation between molecule-iodide binding enthalpy and iodide-CIMS instrument sensitivity, the experimental detection of the HO2 radical was preceded by the quantum chemical calculation of the HO2*I(-) cluster (PBE/aug-cc-pVTZ-PP level), which showed a reasonably strong binding enthalpy of 21...
August 10, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28772808/production-of-high-purity-anhydrous-nickel-ii-perrhenate-for-tungsten-based-sintered-heavy-alloys
#5
Katarzyna Leszczyńska-Sejda, Grzegorz Benke, Dorota Kopyto, Tomasz Majewski, Michał Drzazga
This paper presents a method for the production of high-purity anhydrous nickel(II) perrhenate. The method comprises sorption of nickel(II) ions from aqueous nickel(II) nitrate solutions, using strongly acidic C160 cation exchange resin, and subsequent elution of sorbed nickel(II) ions using concentrated perrhenic acid solutions. After the neutralization of the resulting rhenium-nickel solutions, hydrated nickel(II) perrhenate is then separated and then dried at 160 °C to obtain the anhydrous form. The resulting compound is reduced in an atmosphere of dissociated ammonia in order to produce a Re-Ni alloy powder...
April 24, 2017: Materials
https://www.readbyqxmd.com/read/28771343/new-insight-into-the-aggregation-of-graphene-oxide-using-molecular-dynamics-simulations-and-extended-derjaguin-landau-verwey-overbeek-theory
#6
Huan Tang, Ying Zhao, Xiaonan Yang, Dongmei Liu, Penghui Shao, Zhigao Zhu, Sujie Shan, Fuyi Cui, Baoshan Xing
A comparative experimental and molecular dynamics (MD) simulation study was carried out to investigate the aggregation of graphene oxide (GO). Mechanisms behind the effects of solution chemistries (pH, metal ions, and tannic acid (TA)) and GO topology (carboxyl content, GO size, and GO thickness) were uncovered. For example, MD results showed that more hydrogen bonds formed between GO and water at higher pH, according well with the increased hydrophilicity of GO calculated based on contact angle measurements...
August 3, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28766627/n-heterocyclic-carbene-adducts-of-the-heavier-group-15-tribromides-normal-to-abnormal-isomerism-and-bromide-ion-abstraction
#7
Jordan B Waters, Qien Chen, Thomas A Everitt, Jose M Goicoechea
The reactivity of the heavier group 15 tribromides, SbBr3 and BiBr3, towards 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene (IPr) is described. These reactions quantitatively afford Lewis acid-base adducts, (IPr)EBr3 (E = Sb 1; Bi 2), which readily react with AlBr3 yielding cationic species [(IPr)EBr2](+) (E = Sb 3; Bi 4). Under thermal treatment, the N-heterocyclic carbene ligands in 1 and 2 will readily isomerise to afford the abnormally-bonded (or mesoionic) complexes (aIPr)EBr3 (E = Sb 5; Bi 6). As with 1 and 2, bromide abstraction from such compounds readily affords the cationic complexes [(aIPr)EBr2](+) (E = Sb 7; Bi 8)...
August 2, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28764136/an-eco-friendly-approach-for-heavy-metal-adsorbent-regeneration-using-co2-responsive-molecular-octopus
#8
Yu Bai, Yen Nan Liang, Xiao Hu
Perennial problems of adsorption in wastewater treatment include adsorbent recycling, generation of waste sludge and secondary pollution because harmful concentrated acids, bases or strong chelators are often used for adsorbent regeneration and adsorbate recovery. We report, for the first time, an eco-friendly regeneration concept demonstrated with a CO2-responsive octopus-like polymeric adsorbent. Various heavy metals can be scavenged at very high Qe by such adsorbent through coordination. Most importantly, the rapid and complete regeneration of the adsorbent and recovery of the heavy metal ions can be readily achieved by CO2 bubbling within a few minutes under mild conditions, i...
October 2017: Chemosphere
https://www.readbyqxmd.com/read/28759849/mercaptosuccinic-acid-coated-nir-emitting-gold-nanoparticles-for-the-sensitive-and-selective-detection-of-hg-2
#9
Xiaodong Xiong, Xiaoqi Lai, Jinbin Liu
A sensitive fluorescent detection platform for Hg(2+) was constructed based on mercaptosuccinic acid (MSA) coated near-infrared (NIR)-emitting gold nanoparticles (AuNPs). The thiolated mercaptosuccinic acid was employed as both reducing agent and surface coating ligand in a one-step synthesis of NIR-emitting AuNPs (MSA-AuNPs), which exhibited stable fluorescence with the maximum wavelength at 800nm and a wide range of excitation (220-650nm) with the maxima at 413nm. The MSA coated NIR-emitting AuNPs showed a rapid fluorescence quenching toward Hg(2+) over other metal ions with a limit of detection (LOD, 3δ) as low as 4...
July 23, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28758669/dota-analogues-with-a-phosphinate-iminodiacetate-pendant-arm-modification-of-the-complex-formation-rate-with-a-strongly-chelating-pendant
#10
Soňa Procházková, Vojtěch Kubíček, Zuzana Böhmová, Kateřina Holá, Jan Kotek, Petr Hermann
The new ligand H6do3aP(ida) combines the macrocyclic DOTA-like cavity and the open-chain iminodiacetate group connected through a coordinating phosphinate spacer. Its acid-base and coordination properties in solution were studied by potentiometry. Thermodynamic coordination characteristics of both chelating units are similar to those reported for H4dota and iminodiacetic acid themselves, respectively, so, macrocyclic and iminodiacetate units behave independently. The formation kinetics of the Ce(iii)-H6do3aP(ida) complex was studied by UV-Vis spectrophotometry...
July 31, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28742350/complexation-behavior-of-polyelectrolytes-and-polyampholytes
#11
Arun Kumar Narayanan Nair, Arturo Martinez Jimenez, Shuyu Sun
We perform grand canonical Monte Carlo simulations to study the pH titrations of isolated polyampholytes and polyelectrolyte-polyampholyte complexes in dilute solutions. Our simulations indicate that the electrostatic interactions promote the coexistence of opposite charges along the polyampholyte chain during titration. The repulsion between excess charges typically dominates the electrostatic interaction and leads to polymer stretching. Salt ions can screen the repulsion between excess charges as well as the fluctuation-induced attraction between opposite charges, and therefore make the variation between titration curves of polyampholytes and the ideal (no electrostatic interactions) curves less significant...
August 9, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28741125/identification-of-carboxylate-phosphate-and-phenoxide-functionalities-in-deprotonated-molecules-related-to-drug-metabolites-via-ion-molecule-reactions-with-water-and-diethylhydroxyborane
#12
Hanyu Zhu, Xin Ma, John Y Kong, Minli Zhang, Hilkka I Kenttämaa
Tandem mass spectrometry based on ion-molecule reactions has emerged as a powerful tool for structural elucidation of ionized analytes. However, most currently used reagents were designed to react with protonated analytes, making them suboptimal for acidic analytes that are preferentially detected in negative ion mode. In this work we demonstrate that the phenoxide, carboxylate, and phosphate functionalities can be identified in deprotonated molecules by use of a combination of two reagents, diethylmethoxyborane (DEMB) and water...
July 24, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28738605/rapid-one-pot-synthesis-of-mmta-protected-fluorescent-gold-nanoclusters-for-selective-and-sensitive-detection-of-ferric-ion
#13
Jingjing Jiang, Pengfei Gao, Yan Zhang, Guomei Zhang, Ying Zhou, Chuan Dong, Shaomin Shuang
Herein, we demonstrate a straightforward synthesis of fluorescent gold nanoclusters (AuNCs), employing 2-Mercapto-4-methyl-5-thiazoleacetic acid (MMTA) as a reducing and protecting agent by a rapid one-pot synthesis method with a short time of 20min. The as-synthesized MMTA-AuNCs exhibited bright blue emission with a strong peak centered at 430nm and the quantum yield (QY) was evaluated to be 4.0%. Based on the fluorescence quenching mechanism of a surface chelating reaction between MMTA and ferric ion (Fe(3+)), the MMTA-AuNCs were exploited as a fluorescence sensor for sensitive and selective detection of Fe(3+)...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738076/the-comparison-of-chca-solvent-compositions-for-improving-lc-maldi-performance-and-its-application-to-study-the-impact-of-aflatoxin-b1-on-the-liver-proteome-of-diabetes-mellitus-type-1-mice
#14
Fuu-Jen Tsai, Shih-Yin Chen, Yu-Ching Liu, Hsin-Yi Liao, Chao-Jung Chen
In nanoflow liquid chromatography-matrix-assisted laser desorption/ionization tandem time-of-flight (nanoLC-MALDI-TOF/TOF) approaches, it is critical to directly apply small amounts of the sample elutes on the sample target using a nanoLC system due to its low flow rate of 200 ~ 300 nl/min. It is recommended to apply a sheath liquid containing a matrix with a several μL/min flow rate at the end of the nanoLC column to ensure a larger co-eluted droplet for more reproducible sample spotting and avoid the laborious task of post-manual matrix spotting...
2017: PloS One
https://www.readbyqxmd.com/read/28731301/lead-ii-complexes-of-amino-acids-peptides-and-other-related-ligands-of-biological-interest
#15
Etelka Farkas, Péter Buglyó
Lead(II) forms (NH2,COO-)-chelated mono- and bis-complexes with simple amino acids, while mono-complexes with pH-dependent coordination modes exist with simple dipeptides. These mostly hemidirected complexes have moderate stability. While a weak interaction of side chain imidazole and carboxylate in lead(II)-aminoacidato complexes is found, the thiolate group has an exceptionally high affinity to this metal ion. For example, tridentate (NH2,COO-,S-)-coordination of penicillamine (Pen) and cysteine (Cys) results in an extremely strong interaction with lead(II), but, owing to the sterical effect of the 6s2 pair, a second ligand is not able to coordinate in the above mentioned tridentate way...
April 10, 2017: Metal Ions in Life Sciences
https://www.readbyqxmd.com/read/28730230/magnetic-nanoparticles-based-therapy-for-malignant-mesothelioma
#16
Ion Mîndrilă, Sandra Alice Buteică, Dan Eduard Mihaiescu, Florin Burada, Bogdan Mîndrilă, Maria Cristina Predoi, Ionica Pirici, Adrian Fudulu, Octavian Croitoru
This work was aimed to analyze the versatility of the chick embryo chorioallantoic membrane (CAM) as in vivo model for the study of the malignant pleural mesothelioma (MPM) and the therapeutic potential of Fe3O4÷salicylic acid magnetic nanoparticles (SaMNPs) on MPM cells. The antitumor effects of SaMNPs were studied by in vitro and in vivo tests on CARM-L12 TG3 rat malignant mesothelioma cells and human MPM xenografts implanted on CAMs. In order to assess the human MPM xenograft growth characteristics, calretinin, HBME-1 (Hector Battifora mesothelial epitope-1), and cytokeratins immunohistochemical stainings were performed...
2017: Romanian Journal of Morphology and Embryology, Revue Roumaine de Morphologie et Embryologie
https://www.readbyqxmd.com/read/28728109/zero-valent-aluminum-for-reductive-removal-of-aqueous-pollutants-over-a-wide-ph-range-performance-and-mechanism-especially-at-near-neutral-ph
#17
Shiying Yang, Di Zheng, Tengfei Ren, Yixuan Zhang, Jia Xin
Zero-valent aluminum (ZVAl) draws much attention due to its strong reducibility. However, under neutral pH conditions, the reduction ability of ZVAl for pollutant removal has still been suspected because of the formed compact surface film of Al-(hydr)oxide. In this study, unmodified ZVAl was employed to reductively remove aqueous pollutants over a wide pH range, and its performance and mechanism, especially at near-neutral pH, were systematically studied for the first time. Results demonstrated that ZVAl had a wide range of pH applicability from 2 to 12, even in neutral environment...
July 6, 2017: Water Research
https://www.readbyqxmd.com/read/28693594/the-impact-of-phosphate-balanced-crystalloid-infusion-on-acid-base-homeostasis-palance-study-study-protocol-for-a-randomized-controlled-trial
#18
Judith-Irina Pagel, Nikolai Hulde, Tobias Kammerer, Michaela Schwarz, Daniel Chappell, Alexander Burges, Klaus Hofmann-Kiefer, Markus Rehm
BACKGROUND: This study aims to investigate the effects of a modified, balanced crystalloid including phosphate in a perioperative setting in order to maintain a stable electrolyte and acid-base homeostasis in the patient. METHODS/DESIGN: This is a single-centre, open-label, randomized controlled trial involving two parallel groups of female patients comparing a perioperative infusion regime with sodium glycerophosphate and Jonosteril® (treatment group) or Jonosteril® (comparator) alone...
July 10, 2017: Trials
https://www.readbyqxmd.com/read/28667371/surface-engineered-ho-3-incorporated-fluorescent-dye-doped-bifunctional-silica-nanoparticles-for-receptor-targeted-fluorescence-imaging-and-potential-magnetic-resonance-imaging
#19
Sasidharanpillai S Syamchand, Ravindran S Aparna, Sony George
The authors report Ho(3+) ion incorporated and fluorescent dye-doped silica nanoparticles which are engineered to enable the imaging modalities of receptor targeted fluorescence imaging (FI) and magnetic resonance imaging (MRI). The silica nanoparticles synthesized through a modified Stöber method is luminomagnetic by virtue of the luminescence of organic dye fluorophore (FITC) and magnetism of Ho(3+). The doping concentration of Ho(3+) is estimated by inductively coupled plasma mass spectrometry (ICP-MS) as 0...
June 30, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/28624636/water-geochemistry-of-shallow-lakes-from-the-southeastern-pampa-plain-argentina-and-their-implications-on-mollusk-shells-preservation
#20
Paula A Cristini, Eleonor Tietze, Claudio G De Francesco, Daniel E Martínez
A seasonal sampling of sediments, column and interstitial water for physico-chemical analysis were performed in littoral and open water areas in three freshwater shallow lakes (Nahuel Rucá, Las Mostazas and Los Carpinchos) from Southeastern Pampa plain, Argentina. The main objective of the present study is to evaluate how the characteristics of the depositional environments could be affecting mollusk shell preservation. These lakes are very shallow (2m) and are characterized by an extensive littoral area, dominated by the emergent macrophyte Schoenoplectus californicus, which forms a complete ring around the lake, and an open water area, in general free of vegetation...
June 15, 2017: Science of the Total Environment
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