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https://www.readbyqxmd.com/read/28445812/portable-aptamer-biosensor-of-platelet-derived-growth-factor-bb-using-a-personal-glucose-meter-with-triply-amplified
#1
Lu Hong, Fu Zhou, Dongmin Shi, Xiaojun Zhang, Guangfeng Wang
Sensitive and rapid detection of platelet-derived growth factor BB (PDGF-BB), a cancer-related protein, could help early diagnosis, treatment, and prognosis of cancers. Although some methods have been developed to detect PDGF-BB, few can provide quantitative results using an affordable and portable device that is suitable for home use or field application. In this work, we report the first use of a portable kind of personal glucose meter (PGM) combining a catalytic and molecular beacon (CAMB) system with a cation exchange reaction (CX reaction) for ultrasensitive PDGF-BB assay...
April 19, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28445641/exfoliation-of-lini1-3mn1-3co1-3o2-into-nanosheets-using-electrochemical-oxidation-and-reassembly-with-dialysis-or-flocculation
#2
Qian Cheng, Ting Yang, Man Li, Candace K Chan
Two-dimensional (2D) materials such as nanosheets are increasingly attracting attention for applications in energy storage and conversion. Many conventional battery compounds have layered structures, which can facilitate the exfoliation of these materials into nanosheet morphologies. In this work, LiNi1/3Mn1/3Co1/3O2 (NMC) particles were exfoliated into nanosheets using an electrochemical oxidation method enabled by the intercalation of tetraethylammonium cations into the interlayer space. The exfoliated materials were monolayer or double-layer nanosheets with hexagonal shapes and sizes < 50 nm...
April 26, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28445062/regioselective-functionalization-of-enamides-at-the-%C3%AE-carbon-via-unsymmetrical-2-amidoallyl-cations
#3
Mirza A Saputra, Nitin S Dange, Alexander H Cleveland, Joshua A Malone, Frank R Fronczek, Rendy Kartika
A new method to functionalize enamides via an intermediacy of unsymmetrical 2-amidoallyl cations is reported. Generated under mild Brønsted acid catalysis, these reactive species were found to undergo addition with various nucleophiles at the less substituted α-carbon to produce highly substituted enamides in high yields with complete control of regioselectivity.
April 26, 2017: Organic Letters
https://www.readbyqxmd.com/read/28445054/catalytic-decomposition-of-no-by-cationic-platinum-oxide-cluster-pt3o4
#4
Jun Yamagishi, Ken Miyajima, Satoshi Kudoh, Fumitaka Mafune
The catalytic decomposition of NO by cationic platinum oxide cluster Pt3O4+ was investigated by mass spectrometry and thermal desorption spectrometry. Upon reaction with two NO molecules, molecular oxygen desorbed from the cluster at room temperature to form Pt3O4N2+. Then, at temperatures above 400 K, desorption of N2 from Pt3O4N2+ was observed. These processes were confirmed by isotope-labeling experiments, and the energetics of O2 and N2 release were determined by density functional calculations. The combination of these elementary steps resulted in the catalytic decomposition of NO by Pt3O4+...
April 26, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28445044/highly-oxygenated-multifunctional-compounds-in-%C3%AE-pinene-secondary-organic-aerosol
#5
Xuan Zhang, Andrew T Lambe, Mary Alice Upshur, William A Brooks, Ariana Gray Be, Regan J Thomson, Franz M Geiger, Jason Douglas Surratt, Zhenfa Zhang, Avram Gold, Stephan Graf, Michael J Cubison, Michael Groessl, John T Jayne, Douglas R Worsnop, Manjula R Canagaratna
Highly oxygenated multifunctional organic compounds (HOMs) originating from biogenic emissions constitute a widespread source of organic aerosols in the pristine atmosphere. Yet, the molecular forms in which HOMs are present in the condensed phase upon gas-particle partitioning remain unclear. In this study, we show that highly oxygenated molecules that contain multiple peroxide functionalities are readily cationized by the attachment of Na(+) during electrospray ionization operated in the positive ion mode...
April 26, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28444923/anaerobic-respiration-on-self-doped-conjugated-polyelectrolytes-impact-of-chemical-structure
#6
Nathan D Kirchhofer, Samantha R McCuskey, Cheng-Kang Mai, Guillermo C Bazan
We probe anaerobic respiration of bacteria in the presence of conjugated polyelectrolytes (CPEs). Three different CPEs were used to probe how structural variations impact biocurrent generation from Shewanella oneidensis MR-1. For the self-doped anionic CPE only, absorption spectroscopy shows that the addition of S. oneidensis MR-1 leads to the disappearance of the polaron (radical cation) band at >900 nm and an increase in the band at 735 nm due to the neutral species, consistent with electron transfer from microbe to polymer...
April 26, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28443929/construction-of-protein-assemblies-by-host-guest-interactions-with-cucurbiturils
#7
REVIEW
Chunxi Hou, Zupeng Huang, Yu Fang, Junqiu Liu
Protein assemblies are extremely interesting in chemistry and supramolecular chemistry. How to design protein assemblies with dimensional structures is important for applications. To address this challenge, cucurbituril (CB[n]s)-based strategies have been explored owing to their high affinity toward small peptide motifs, organic cations and amines. By incorporation of a small molecule guest and a peptide motif guest into N-terminals of oligomeric proteins, CB[n]s could recognize and bind to the N-terminal guests, leading to dimensional protein assemblies...
April 26, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28443924/investigations-on-the-photochromic-properties-of-2-6-bis-5-bromo-2-hydroxybenzylidene-cyclohexanone
#8
L N Corîci, S Shova, V Badea, D Aparaschivei, O Costisor, L Cseh
The network of chemical reactions of 2,6-bis(5-bromo-2-hydroxybenzylidene)cyclohexanone (BHBC) when subjected to light and different pH values has been investigated. The pH dependent species involved in the chemical network have been identified and characterized by NMR and UV-VIS spectroscopy. Direct pH jumps were carried out by adding a strong acid to equilibrated solutions of trans-chalcone (Ct) forming the flavylium cation which was stable only under extremely acidic conditions (pH < 0.5). The single crystal X-ray study and NMR analysis has confirmed the structure of the new flavylium cation...
April 26, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28443912/flux-synthesis-crystal-structures-and-physical-properties-of-new-lanthanum-vanadium-oxyselenides
#9
Simon Peschke, Lisa Gamperl, Valentin Weippert, Dirk Johrendt
The new lanthanum vanadium oxyselenides LaVSe2O, La5V3Se6O7, La5V3Se7O5, La7VSe5O7, and La13V7Se16O15 were synthesized in eutectic NaI/KI fluxes, and their crystal structures were determined using single-crystal and powder X-ray diffraction experiments. LaVSe2O and La5V3Se6O7 adopt known structure types, whereas La5V3Se7O5, La7VSe5O7, and La13V7Se16O15 crystallize in hitherto unknown structure types. The main building blocks of these compounds are chains of edge-sharing VSe6, VSe5O, and/or VSe4O2 octahedra, linked together by edge-sharing OLa4 and/or OLa3V tetrahedra forming fluorite-like ribbons...
April 26, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28443889/the-passivating-effect-of-cadmium-in-pbs-cds-colloidal-quantum-dots-probed-by-nm-scale-depth-profiling
#10
Pip C J Clark, Hanna Radtke, Atip Pengpad, Andrew I Williamson, Ben F Spencer, Samantha J O Hardman, Marina A Leontiadou, Darren C J Neo, Simon M Fairclough, Andrew A R Watt, Igor Pis, Silvia Nappini, Federica Bondino, Elena Magnano, Karsten Handrup, Karina Schulte, Mathieu G Silly, Fausto Sirotti, Wendy R Flavell
Achieving control of the surface chemistry of colloidal quantum dots (CQDs) is essential to fully exploit their properties in solar cells, but direct measurement of the chemistry and electronic structure in the outermost atomic layers is challenging. Here we probe the surface oxidation and passivation of cation-exchanged PbS/CdS core/shell CQDs with sub nm-scale precision using synchrotron-radiation-excited depth-profiling photoemission. We investigate the surface composition of the topmost 1-2.5 nm of the CQDs as a function of depth, for CQDs of varying CdS shell thickness, and examine how the surface changes after prolonged air exposure...
April 26, 2017: Nanoscale
https://www.readbyqxmd.com/read/28443887/metal-ion-induced-supramolecular-pka-tuning-and-fluorescence-regeneration-of-a-p-sulfonatocalixarene-encapsulated-neutral-red-dye
#11
M N Shinde, R Khurana, N Barooah, A C Bhasikuttan, J Mohanty
The host-guest interactions and the consequent modulation in the prototropic equilibrium of a phenazine dye, neutral red, with p-sulfonatocalix[4]arene (SCX4) and p-sulfonatocalix[6]arene (SCX6) macrocyclic hosts have been investigated. Both the neutral (NR) and cationic (NRH(+)) forms of dyes formed inclusion complexes with SCX6, with a larger binding constant for the latter (K = 8.6 × 10(5) M(-1)versus 4.8 × 10(3) M(-1)) due to the cation receptor behavior of the calixarenes. The distinct differences in the binding constant of NR and NRH(+) provided a finite tuning of pKa between 6...
April 26, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28443870/operando-x-ray-spectroscopic-observations-of-modulations-of-local-atomic-and-electronic-structures-of-color-switching-smart-film
#12
Ying-Rui Lu, Tzung-Zing Wu, Han-Wei Chang, Jeng-Lung Chen, Chi-Liang Chen, Da-Hau Wei, Jin-Ming Chen, Wu-Ching Chou, Chung-Li Dong
Smart windows, which change color in response to external stimuli, are extensively studied owing to their potential technological applications in sensors and their ability to reduce the energy consumed by buildings. Most related studies focus on the optical properties of smart color switching films that can control the transmission of light and that of heat independently. This study examines the vanadium pentoxide thin film as a model system of a color switchable window. A gasochromic thin film of V2O5 is fabricated using sol-gel spin coating...
April 26, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28443813/vacuolar-h-atpase-subunit-vma1p-functions-as-the-molecular-ligand-in-the-vacuole-targeting-fungicidal-activity-of-polymyxin-b
#13
Maki Iida, Keiichi Yamada, Yoshiya Nango, Yoshihiro Yamaguchi, Akira Ogita, Ken-Ichi Fujita, Toshio Tanaka
Polymyxin B (PMB) is a cationic cyclic peptide that can selectively inhibit the growth of Gram-negative bacteria by disrupting the outer membrane permeability barrier through binding to lipopolysaccharide (LPS). Here, a fluorescent PMB derivative (PMB-Ds) was applied to visually confirm the vacuole as a direct lethal target of PMB against fungal cells, which lack LPS. PMB-Ds could be visualized in the normal rounded vacuolar membrane of Saccharomyces cerevisiae cells, suggesting the presence of a molecular ligand assisting the vacuole-targeting mobilization of the peptide in the organism...
April 2017: Microbiology
https://www.readbyqxmd.com/read/28443064/loss-of-vagal-sensitivity-to-cholecystokinin-in-rats-born-with-intrauterine-growth-retardation-and-consequence-on-food-intake
#14
Marième Ndjim, Camille Poinsignon, Patricia Parnet, Gwenola Le Dréan
Perinatal malnutrition is associated with low birth weight and an increased risk of developing metabolic syndrome in adulthood. Modification of food intake (FI) regulation was observed in adult rats born with intrauterine growth retardation induced by maternal dietary protein restriction during gestation and maintained restricted until weaning. Gastrointestinal peptides and particularly cholecystokinin (CCK) play a major role in short-term regulation of FI by relaying digestive signals to the hindbrain via the vagal afferent nerve (VAN)...
2017: Frontiers in Endocrinology
https://www.readbyqxmd.com/read/28443028/improved-model-of-proton-pump-crystal-structure-obtained-by-interactive-molecular-dynamics-flexible-fitting-expands-the-mechanistic-model-for-proton-translocation-in-p-type-atpases
#15
Dorota Focht, Tristan I Croll, Bjorn P Pedersen, Poul Nissen
The plasma membrane H(+)-ATPase is a proton pump of the P-type ATPase family and essential in plants and fungi. It extrudes protons to regulate pH and maintains a strong proton-motive force that energizes e.g., secondary uptake of nutrients. The only crystal structure of a H(+)-ATPase (AHA2 from Arabidopsis thaliana) was reported in 2007. Here, we present an improved atomic model of AHA2, obtained by a combination of model rebuilding through interactive molecular dynamics flexible fitting (iMDFF) and structural refinement based on the original data, but using up-to-date refinement methods...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28442707/polyanionic-cyclodextrin-induced-supramolecular-nanoparticle
#16
He-Lue Sun, Ying-Ming Zhang, Yong Chen, Yu Liu
Ionizable cyclodextrins have attracted increasing attention in host-guest chemistry and pharmaceutical industry, mainly due to the introduction of favorable electrostatic interactions. The ionizable cyclodextrins could not only enhance its own solubility but also induce oppositely charged guests to form more stable complex. However, the aggregation induced by charged cyclodextrins has rarely been reported. In this work, guided by the concept of molecular-induced aggregation, a series of carboxyl modified cyclodextrins were synthesized via "click" and hydrolysis reaction...
December 23, 2016: Scientific Reports
https://www.readbyqxmd.com/read/28442564/on-the-permeation-of-large-organic-cations-through-the-pore-of-atp-gated-p2x-receptors
#17
Mahboubi Harkat, Laurie Peverini, Adrien H Cerdan, Kate Dunning, Juline Beudez, Adeline Martz, Nicolas Calimet, Alexandre Specht, Marco Cecchini, Thierry Chataigneau, Thomas Grutter
Pore dilation is thought to be a hallmark of purinergic P2X receptors. The most commonly held view of this unusual process posits that under prolonged ATP exposure the ion pore expands in a striking manner from an initial small-cation conductive state to a dilated state, which allows the passage of larger synthetic cations, such as N-methyl-d-glucamine (NMDG(+)). However, this mechanism is controversial, and the identity of the natural large permeating cations remains elusive. Here, we provide evidence that, contrary to the time-dependent pore dilation model, ATP binding opens an NMDG(+)-permeable channel within milliseconds, with a conductance that remains stable over time...
April 25, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28441865/unexpected%C3%A2-effects%C3%A2-of%C3%A2-k-%C3%A2-and%C3%A2-adenosine-triphosphate%C3%A2-on%C3%A2-the-thermal%C3%A2-stability%C3%A2-of%C3%A2-na-k-atpase
#18
M Agueda Placenti, Sergio Benjamín Benjamin Kaufman, F Luis Gonzalez Flecha, Rodolfo Martín González-Lebrero
Na(+),K(+)-ATPase is an integral membrane protein which couples ATP hydrolysis to the transport of three Na(+) out and two K(+) into the cell. The aim of this work is to characterize the effect of K(+), ATP and Mg(2+) (essential activator) on the Na(+),K(+)-ATPase thermal stability. In all conditions tested, thermal inactivation of the enzyme is concomitant with a structural change involving the ATP binding site and membrane-associated regions. Both ligands exert a clear stabilizing effect due to both enthalpic and entropic contributions...
April 25, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28441860/smart-luminescent-coordination-polymers-towards-multi-mode-logic-gates-time-resolved-tribochromic-and-excitation-dependent-fluorescence-phosphorescence-emission
#19
Yongsheng Yang, Ke-Zhi Wang, Dongpeng Yan
In this work, we propose that lanthanide cations (such as Eu3+ and Tb3+) doped long-afterglow coordination polymer (CP) can be an effective way to design multi-mode optical logic gates based on their tunable fluorescence/phosphorescence transformation and state-dependent emission. First, multi-color and white-light luminescence across the blue/green/yellow/red visible regions can be obtained by balancing the co-doping ratio of Eu3+/Tb3+ cations and suitable excitations. Additionally, new mechanochromic Eu-Cd-CP was developed based on the mechanism of change in structural symmetry...
April 26, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28441858/-development-of-an-eosinophilic-bronchitis-mouse-model-and-the-effects-of-eosinophil-activation-on-airway-hyperresponsiveness-in-eosinophilic-bronchitis-mice
#20
L Li, J T Lin
Objective: To develop a mouse model of eosinophilic bronchitis, and explore the effects of eosinophil activation on airway hyperresponsiveness. Methods: A total of 60 female specific pathogen free BALB/c female mice were divided randomly into four groups: polymyxin B group, normal saline group, polymyxin B+ N-methionine leucine phenylalanine (fMLP) group, normal saline+ fMLP group. All the groups were given corresponding nasal drops for 21 days. The former two groups were given 12 μl 0.5% polymyxin B or normal saline once a day by transnasal administration respectively...
April 25, 2017: Zhonghua Yi Xue za Zhi [Chinese medical journal]
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