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Ena Kiyokawa, Tadashi Hayama, Hideyuki Yoshida, Masatoshi Yamaguchi, Hitoshi Nohta
We herein developed a selective method for the determination of nucleotides by fluorous-assisted metal chelate affinity extraction followed by hydrophilic interaction liquid chromatography (HILIC) combined with tandem mass spectrometric (MS/MS) analysis. In this study, the nucleotides were selectively chelated by Fe(III)-immobilized perfluoroalkyliminodiacetic acid, and the resulting chelates were subsequently extracted into a fluorous solvent. The nucleotides present in the fluorous solvent were then back-extracted into a non-fluorous solution, such as a solution of ammonia in aqueous acetonitrile...
January 3, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Sadegh Yaghoubnejad, Kourosh Tabar Heydar, Seyyed Hamid Ahmadi, Reza Zadmard, Nima Ghonouei
We report the synthesis and enantioseparation characteristics of two novel covalently immobilized deoxycholic acid derivatives as chiral stationary phases for high-performance liquid chromatography. In the structure of the first stationary phase, the 3-position of deoxycholic acid is substituted with a 3,5-dinitrophenylcarbamoyl group and the second one has an additional calix[4]arene attached to the carboxylic group of the deoxycholic acid. The chromatographic performance of the stationary phases was evaluated with enantioseparation of N-(3,5-dinitrobenzoyl)-dl-leucine, N-(3,5-dinitrobenzoyl)-dl-valine, omeprazole, diclofop-methyl, dl-mandelic acid and (RS)-pregabalin...
January 15, 2018: Journal of Separation Science
Meriem Bouanini, Nasser Belboukhari, J Carlos Menéndez, Khaled Sekkoum, Abdelkarim Cheriti, Hassan Y Aboul-Enein
A series of 4-iminonaringenin derivatives 2-6 have been prepared in good overall yields from a condensation reaction between naringenin and primary amines. The structures of all products were confirmed by ultraviolet, infrared, proton nuclear magnetic resonance, and carbon-13 nuclear magnetic resonance spectroscopic techniques. These derivatives were analyzed by high-performance liquid chromatography using polysaccharide-based chiral stationary phases, namely, Chiralpak IB and Chiralcel OD, using various mobile phases...
January 15, 2018: Chirality
Emilio Satoshi Hara, Masahiro Okada, Noriyuki Nagaoka, Takako Hattori, Letycia Mary Iida, Takuo Kuboki, Takayoshi Nakano, Takuya Matsumoto
Analysis of tissue development from multidisciplinary approaches can result in more integrative biological findings, and can eventually allow the development of more effective bioengineering methods. In this study, we analyzed the initial steps of mineral formation during secondary ossification of mouse femur based on biological and bioengineering approaches. We first found that some chondrocytes burst near the mineralized area. External factors that could trigger chondrocyte burst were then investigated. Chondrocyte burst was shown to be modulated by mechanical and osmotic pressure...
January 15, 2018: Integrative Biology: Quantitative Biosciences From Nano to Macro
Dongyue Jiang, Seunguk Lee, Sung Woo Bae, Sung-Yong Park
With the increasing capabilities and ubiquity of smartphones and their associated digital cameras, this study presents a smartphone integrated optoelectrowetting (SiOEW) device as a simple, portable tool capable of on-chip water sample preparation and microscopic detection of the target cells in water samples, which significantly reduce the detection time and the labor cost required for water quality monitoring. A commercially available smartphone is used as a low-intensity portable light source to perform optoelectrowetting (OEW)-based microfluidic operations such as droplet transportation, merging, mixing, and immobilization on a hydrophobic detection zone...
January 15, 2018: Lab on a Chip
Ke-Feng Wang, Chun-Lei Liu, Kun-Yan Sui, Chen Guo, Chun-Zhao Liu
2,5-Furandicarboxylic acid (FDCA) is a biobased platform chemical for the production of polyesters. The magnetic laccase catalyst with TEMPO as the mediator has the remarkable capability of oxidizing HMF to 2,5-furandicarboxylic acid (FDCA). Under optimal reaction conditions, a quantitative yield (90.2%) of FDCA with complete HMF conversion was obtained after 96 h of reaction. More importantly, the magnetic laccase catalyst exhibited good recyclability and stability, maintaining 84.8% of its original activity following 6 reuse cycles...
January 15, 2018: Chembiochem: a European Journal of Chemical Biology
Jie Zhang, Ying Chen, Yunxia Chen, Chenchen Wang, Jing Cai, Kaiyue Chu, Jianhua Jin, Yun Ge, Xiaolin Huang, Yue Guan, Weifeng Li
PURPOSE: To minimize the mismatch error between patient surface and immobilization system for tumor location by a noninvasive patient setup method. MATERIALS AND METHODS: The method, based on a point set registration, proposes a shift for patient positioning by integrating information of the computed tomography scans and that of optical surface landmarks. An evaluation of the method included 3 areas: (1) a validation on a phantom by estimating 100 known mismatch errors between patient surface and immobilization system...
December 2017: Technology in Cancer Research & Treatment
Tao Chen, Yuanhong Xu, Wenrong Yang, Aihua Li, Yao Wang, Jing Sun, Jingquan Liu
Concavo-convex micelles with controllable sizes and nanostructures are prepared via self-assembling polymer-enzyme (e.g., shellac enzyme) conjugates with heterogeneous polymer chains, which exhibit higher enzyme stability (300%) and bioactivity (760%) comparing with the well-defined ones. The applied amphiphilic and negatively charged copolymer, poly (methyl methacrylate)-block-poly (sodium p-styrene sulfonate), is synthesized via reversible addition-fragmentation chain transfer polymerization to modify shellac enzyme and immobilize the enzyme bioactivity inducer by covalent conjugation and electrostatic attraction, respectively...
January 15, 2018: Macromolecular Bioscience
Minoru Waki, Ken-Ichi Yamanaka, Soichi Shirai, Yoshifumi Maegawa, Yasutomo Goto, Yuri Yamada, Shinji Inagaki
This paper describes the physicochemical properties of a rhenium (Re) complex [Re(bpy)(CO)3Cl] immobilized on a bipyridine-periodic mesoporous organosilica (BPy-PMO) acting as a solid support. The immobilized Re complex generated a metal-to-ligand charge transfer absorption band at 400 nm. This wavelength is longer than that exhibited by Re(bpy)(CO)3Cl in the polar solvent acetonitrile (371 nm) and is almost equal to that in nonpolar toluene (403 nm). The photocatalytic activity of this heterogeneous Re complex was lower than that of a homogeneous Re complex due to the reduced phosphorescence lifetime resulting from immobilization...
January 14, 2018: Chemistry: a European Journal
Laurent Liardet, Xile Hu
The water-splitting reaction provides a promising mechanism to store renewable energies in the form of hydrogen fuel. The oxidation half-reaction, the oxygen evolution reaction (OER), is a complex four-electron process that constitutes an efficiency bottleneck in water splitting. Here we report a highly active OER catalyst, cobalt vanadium oxide. The catalyst is designed on the basis of a volcano plot of metal-OH bond strength and activity. The catalyst can be synthesized by a facile hydrothermal route. The most active pure-phase material (a-CoVO x ) is X-ray amorphous and provides a 10 mA cm-2 current density at an overpotential of 347 mV in 1 M KOH electrolyte when immobilized on a flat substrate...
January 5, 2018: ACS Catalysis
Peter Stenvinkel, Johanna Painer, Makoto Kuro-O, Miguel Lanaspa, Walter Arnold, Thomas Ruf, Paul G Shiels, Richard J Johnson
Many of the >2 million animal species that inhabit Earth have developed survival mechanisms that aid in the prevention of obesity, kidney disease, starvation, dehydration and vascular ageing; however, some animals remain susceptible to these complications. Domestic and captive wild felids, for example, show susceptibility to chronic kidney disease (CKD), potentially linked to the high protein intake of these animals. By contrast, naked mole rats are a model of longevity and are protected from extreme environmental conditions through mechanisms that provide resistance to oxidative stress...
January 15, 2018: Nature Reviews. Nephrology
Jack Strand, Moloud Kaviani, Valeri V Afanas'ev, Judit Lisoni, Alexander L Shluger
We demonstrate that electron trapping at intrinsic precursor sites is endemic to non-glass-forming amorphous oxide films. The energy distributions of trapped electron states in ultra-pure prototype amorphous (a)-HfO<sub>2</sub> insulator obtained from exhaustive photo-depopulation experiments demonstrate the electron states in the energy range of 2-3 eV below the oxide conduction band. These energy distributions are compared to the results of density functional calculations of a-HfO<sub>2</sub> models of realistic density...
January 15, 2018: Nanotechnology
Min Tang, Zhenxian Zhou, Li Shangguan, Fang Zhao, Songqin Liu
This work proposed an electrochemiluminescence (ECL) immunosensor for quantitative monitoring of cardiac troponin I (cTnI) in plasma with soybean peroxidase (SBP) labeled-antibody as signal amplifier. The ECL sandwich immunosensor was constructed by covalent binding anti-cTnI capture antibody (Ab1) to polyethylenimine-functionalized graphene matrix, which was obtained by a simple hydrothermal reaction between polyethylenimine (PEI) and graphene oxide (GO). After that, the SBP-labeled detection antibody (SBP-Ab2), synthesized by NaIO4 method, was immobilized on the surface of electrode through sandwich immunoreaction...
April 1, 2018: Talanta
Dandan Jiang, Xiqian Li, Jiutong Ma, Qiong Jia
In this study, we designed a gadolinium-based immobilized metal ion affinity chromatography material for the selective enrichment of phosphopeptides. Gadolinium ion was immobilized on the surface of glutathione-coated magnetic nanoparticles through a facile and effective synthetic route. The adsorbent integrated the advantages of superparamagnetism of Fe3O4 core, good biological compatibility of glutathione, and strong interaction between gadolinium ion and phosphopeptides. It was employed to enrich phosphopeptides from standard protein digests coupled with MALDI-TOF MS...
April 1, 2018: Talanta
Zhen Wang, Xiaoqing Li, Menghan Chen, Feiyan Liu, Chao Han, Lingyi Kong, Jianguang Luo
A new method based on ligand fishing combined with high-performance liquid chromatography quadrupole-time-of-flight mass spectrometer and molecular docking was established to screen α-glucosidase inhibitors from a traditional Chinese medicine Morus alba root bark. α-Glucosidase was immobilized on magnetic nanoparticles, used as a solid support to incubate with crude extract. After ligand fishing, the eluates were analyzed by high-performance liquid chromatography quadrupole-time-of-flight mass spectrometer, obtaining eleven ligands (1-4, 6-12) eventually...
April 1, 2018: Talanta
Adam Kecskemeti, Attila Gaspar
The research and applications of immobilized enzyme reactors (IMERs) have become more and more widespread due to the numerous advantages like reusability, easy handling, prolonged lifetime, easy separation from products and substrate specificity. The miniaturized form of these reactors (microchip IMERs) received outstanding attention due to their special features and advantages over the traditional, larger analytical systems. Large specific surface is essential for the efficient operation of the microreactors, thus these devices include one of the several types of porous solid supports, but in this work only the particle based microchip IMERs are reviewed...
April 1, 2018: Talanta
Yi-Kun Li, Ting Yang, Ming-Li Chen, Jian-Hua Wang
Carbon dots were prepared via a one-pot hydrothermal route, and a new solid-phase extraction (SPE) adsorbent was developed by immobilizing the carbon dots on the microcarrier cytopore, shortly termed as C-dots@cytopore. The C-dots@cytopore composites were characterized by means of FT-IR, SEM, XPS and fluorescence spectrometry. The performance of the composites for the adsorption of heavy metals was thoroughly evaluated by using cadmium as a model. The binding of cadmium on C-dots@cytopore fits Langmuir adsorption, and the adsorption dynamic follows pseudo-second-order adsorption kinetics model...
April 1, 2018: Talanta
Shuo Li, Qiong Wu, Pinyi Ma, Yue Zhang, Daqian Song, Xinghua Wang, Ying Sun
A novel surface plasmon resonance (SPR) biosensor based on hollow gold nanospheres (HGNPs) and an improved sandwich assay was developed to detect rabbit IgG. The electromagnetic coupling between the HGNPs and Au film, and the notable plasmonic fields spread over the inner and outer surfaces of HGNPs, led to the considerable amplification of the SPR signal. Polydopamine-Ag@Fe3O4/reduced graphene oxide (PDA-Ag@Fe3O4/rGO) was introduced to bind detection antibody (Ab2) to form the improved sandwich structure. Ag nanoparticles were excited to produce SPR and their hot electrons were doped on graphene thin films, which amplified the response of biomolecules...
April 1, 2018: Talanta
Minyu Xiao, Joshua Jasensky, Leanna L Foster, Kenichi Kuroda, Zhan Chen
Antimicrobial peptides (AMPs) free in solution can kill bacteria by disrupting bacterial cell membranes. Their modes of action have been extensively studied and various models ranging from Pore formation to Carpet-like mechanism were proposed. Surface immobilized AMPs have been used as coatings to kill bacteria and as sensors to capture bacteria, but the interaction mechanisms of surface immobilized AMPs and bacteria are not fully understood. In this research, an analytical platform, SFG-microscope, which is composed of a sum frequency generation (SFG) vibrational spectrometer and a fluorescence microscope, was used to probe molecular interactions between surface immobilized AMPs and bacteria in situ in real time at the solid/liquid interface...
January 15, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Antoine Brehault, Deepak Patil, Hrishikesh Kamat, Randall E Youngman, Lynn M Thirion, John C Mauro, Claire Corkhill, John Stuart McCloy, Ashutosh Goel
Molybdenum oxides are an integral component of the high-level waste streams being generated from the nuclear reactors in several countries. Although borosilicate glass has been chosen as the baseline waste form by most of the countries to immobilize these waste streams, molybdate oxyanions (MoO42-) exhibit very low solubility (~ 1 mol.%) in these glass matrices. In the past 3-4 decades, several studies describing the compositional and structural dependence of molybdate anions in borosilicate and aluminoborosilicate glasses have been reported in the literature, providing a basis for our understanding of fundamental science that governs the solubility and retention of these species in the nuclear waste glasses...
January 14, 2018: Journal of Physical Chemistry. B
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