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https://www.readbyqxmd.com/read/28339236/effect-of-biaxial-strain-on-the-phase-transitions-of-ca-fe_-1-x-co_-x-_-2-as_-2
#1
A E Böhmer, A Sapkota, A Kreyssig, S L Bud'ko, G Drachuck, S M Saunders, A I Goldman, P C Canfield
We study the effect of applied strain as a physical control parameter for the phase transitions of Ca(Fe_{1-x}Co_{x})_{2}As_{2} using resistivity, magnetization, x-ray diffraction, and ^{57}Fe Mössbauer spectroscopy. Biaxial strain, namely, compression of the basal plane of the tetragonal unit cell, is created through firm bonding of samples to a rigid substrate via differential thermal expansion. This strain is shown to induce a magnetostructural phase transition in originally paramagnetic samples, and superconductivity in previously nonsuperconducting ones...
March 10, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28339179/synthesis-of-111-facet-exposed-mgo-with-surface-oxygen-vacancies-for-ros-generation-in-the-dark
#2
Ying-Juan Hao, Bing Liu, Li-Gang Tian, Fa-Tang Li, Jie Ren, Shao-Jia Liu, Ying Liu, Jun Zhao, Xiaojing Wang
Seeking a simple and moderate route to generate reactive oxygen species (ROS) for antibiosis is of great interest and challenge. This work demonstrates that molecule transition and electron rearrangement processes can directly occur only through chemisorption interaction between the adsorbed O2 and high-energy {111} facet-exposed MgO with abundant surface oxygen vacancies (SOVs), hence producing singlet oxygen and superoxide anion radicals without light irradiation. These ROS were confirmed by electron paramagnetic resonance, in-situ Raman and scavenger experiments, respectively...
March 24, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28338634/construction-of-an-acetylcholinesterase-sensor-based-on-synthesized-paramagnetic-nanoparticles-a-simple-tool-for-neurotoxic-compounds-assay
#3
Adam Kostelnik, Pavel Kopel, Alexander Cegan, Miroslav Pohanka
Magnetic particles (MPs) have been widely used in biological applications in recent years as a carrier for various molecules. Their big advantage is in repeated use of immobilized molecules including enzymes. Acetylcholinesterase (AChE) is an enzyme playing crucial role in neurotransmission and the enzyme is targeted by various molecules like Alzheimer's drugs, pesticides and warfare agents. In this work, an electrochemical biosensor having AChE immobilized onto MPs and stabilized through glutaraldehyde (GA) molecule was proposed for assay of the neurotoxic compounds...
March 24, 2017: Sensors
https://www.readbyqxmd.com/read/28336897/three-dimensional-bioi-biox-x-cl-or-br-nanohybrids-for-enhanced-visible-light-photocatalytic-activity
#4
Yazi Liu, Jian Xu, Liqiong Wang, Huayang Zhang, Ping Xu, Xiaoguang Duan, Hongqi Sun, Shaobin Wang
Three-dimensional flower-like BiOI/BiOX (X = Br or Cl) hybrids were synthesized via a facile one-pot solvothermal approach. With systematic characterizations by X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), the Brunauer-Emmett-Teller (BET)specific surface area, X-ray photoelectron spectroscopy (XPS), and the UV-Vis diffuse reflectance spectra (DRS), the BiOI/BiOCl composites showed a fluffy and porous 3-D architecture with a large specific surface area (SSA) and high capability for light absorption...
March 14, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28336347/solution-conformations-of-a-linked-construct-of-the-zika-virus-ns2b-ns3-protease
#5
Mithun C Mahawaththa, Benjamin J G Pearce, Bim Graham, Christian D Klein, Christoph Nitsche, Gottfried Otting
The Zika virus presents a serious risk for global health. Crystal structures of different constructs of the Zika virus NS2B-NS3 protease (NS2B-NS3pro) have been determined with the aim to provide a basis for rational drug discovery. In these structures, the C-terminal β-hairpin of NS2B, NS2Bc, was observed to be either disordered (open conformation) or bound to NS3pro complementing the substrate binding site (closed conformation). Enzymatically active constructs of flaviviral NS2B-NS3 proteases commonly used for inhibitor testing contain a covalent peptide linker between NS2B and NS3pro...
March 20, 2017: Antiviral Research
https://www.readbyqxmd.com/read/28336314/non-linear-van-t-hoff-behavior-in-pulmonary-surfactant-model-membranes
#6
Ernanni D Vieira, Luis G M Basso, Antonio J Costa-Filho
Pulmonary surfactant exhibits phase coexistence over a wide range of surface pressure and temperature. Less is known about the effect of temperature on pulmonary surfactant models. Given the lack of studies on this issue, we used electron paramagnetic resonance (EPR) and nonlinear least-squares (NLLS) simulations to investigate the thermotropic phase behavior of the matrix that mimics the pulmonary surfactant lipid complex, i.e. the lipid mixture composed of dipalmitoyl phosphatidylcholine (DPPC), palmitoyl-oleoyl phosphatidylcholine (POPC) and palmitoyl-oleoyl phosphatidylglycerol (POPG)...
March 20, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28333095/cytosolic-bnip3-dimer-interacts-with-mitochondrial-bax-forming-heterodimers-in-the-mitochondrial-outer-membrane-under-basal-conditions
#7
Ulrike B Hendgen-Cotta, Sonja Esfeld, Katharina Rudi, Ilkka Miinalainen, Johann P Klare, Tienush Rassaf
The primary function of mitochondria is energy production, a task of particular importance especially for cells with a high energy demand like cardiomyocytes. The B-cell lymphoma (BCL-2) family member BCL-2 adenovirus E1B 19 kDa-interacting protein 3 (BNIP3) is linked to mitochondrial targeting after homodimerization, where it functions in inner membrane depolarization and permeabilization of the mitochondrial outer membrane (MOM) mediating cell death. We investigated the basal distribution of cardiac BNIP3 in vivo and its physical interaction with the pro-death protein BCL2 associated X, apoptosis regulator (BAX) and with mitochondria using immunoblot analysis, co-immunoprecipitation, and continuous wave and pulsed electron paramagnetic resonance spectroscopy techniques...
March 23, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28332833/uranyl-peroxide-clusters-incorporating-iron-trimers-and-bridging-by-bisphosphonate-and-carboxylate-containing-ligands
#8
Jie Qiu, Sining Dong, Jennifer E S Szymanowski, Malgorzata Dobrowolska, Peter C Burns
A hybrid uranium-iron cage nanocluster, [(UO2)24(FeOH)24(O2)24(PO4)8(CH(COO)(PO3)2)24](96-) (U24Fe24), was synthesized using bridging ligands containing bisphosphonate and carboxylate groups. U24Fe24 contains six tetramers of uranyl hexagonal bipyramids and eight iron trimers, each of which consists of three corner-sharing Fe(3+) octahedra and is stabilized by in situ formed phosphate and 2,2-bis(phosphonato)acetate (C2P2) groups. Tetramers and trimers are bridged by 24 C2P2 groups into a cage cluster. Crystals of U24Fe24 present a paramagnetic-like behavior...
March 23, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28332672/formation-of-paramagnetic-metallacyclobutadienes-by-reaction-of-diaminoacetylenes-with-molybdenum-alkylidyne-complexes
#9
Òscar Àrias, Kai Brandhorst, Dirk Baabe, Matthias Freytag, Peter G Jones, Matthias Tamm
The reactions of the molybdenum alkylidyne complex [MesC[triple bond, length as m-dash]Mo{OCMe(CF3)2}3] (1) with the diaminoacetylenes R2NC[triple bond, length as m-dash]CNR2 (2, NR2 = 4-methylpiperidinyl; 3, NR2 = NEt2; Mes = 2,4,6-trimethylphenyl) afforded the metallacyclobutadiene (MCBD) complexes 4 and 5. In contrast to all other MCBD complexes, 4 and 5 are paramagnetic and best described as Mo(iv) species containing an anionic diaminodicarbene of the type [(R2N)CC(Mes)C(NR2)](-).
March 23, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28328524/paramagnetic-micro-particles-as-a-tool-for-rapid-quantification-of-apixaban-dabigatran-edoxaban-and-rivaroxaban-in-human-plasma-by-uhplc-ms-ms
#10
Martin H J Wiesen, Cornelia Blaich, Thomas Streichert, Guido Michels, Carsten Müller
BACKGROUND: Assessment of the anticoagulant activity of direct oral anticoagulants (DOACs) is justified in special clinical situations. Here, we evaluated two independent extraction methods and developed a multi-analyte ultra-high performance liquid chromatography tandem mass (UHPLC-MS/MS) method for the quantification of apixaban, dabigatran, edoxaban and rivaroxaban in human plasma. METHODS: Routine extraction based on protein precipitation with acetonitrile and subsequent centrifugation was compared to sample clean-up using commercial paramagnetic micro-particles and subsequent magnetic depletion...
March 22, 2017: Clinical Chemistry and Laboratory Medicine: CCLM
https://www.readbyqxmd.com/read/28328212/cu-ii-based-paramagnetic-probe-to-study-rna-protein-interactions-by-nmr
#11
Leah M Seebald, Christopher M DeMott, Srivathsan Ranganathan, Papa Nii Asare Okai, Anastasia Glazunova, Alan Chen, Alexander Shekhtman, Maksim Royzen
Paramagnetic NMR techniques allow for studying three-dimensional structures of RNA-protein complexes. In particular, paramagnetic relaxation enhancement (PRE) data can provide valuable information about long-range distances between different structural components. For PRE NMR experiments, oligonucleotides are typically spin-labeled using nitroxide reagents. The current work describes an alternative approach involving a Cu(II) cyclen-based probe that can be covalently attached to an RNA strand in the vicinity of the protein's binding site using "click" chemistry...
March 22, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28327654/constructive-quantum-interference-in-a-bis-copper-six-porphyrin-nanoring
#12
Sabine Richert, Jonathan Cremers, Ilya Kuprov, Martin D Peeks, Harry L Anderson, Christiane R Timmel
The exchange interaction, J, between two spin centres is a convenient measure of through bond electronic communication. Here, we investigate quantum interference phenomena in a bis-copper six-porphyrin nanoring by electron paramagnetic resonance spectroscopy via measurement of the exchange coupling between the copper centres. Using an analytical expression accounting for both dipolar and exchange coupling to simulate the time traces obtained in a double electron electron resonance experiment, we demonstrate that J can be quantified to high precision even in the presence of significant through-space coupling...
March 22, 2017: Nature Communications
https://www.readbyqxmd.com/read/28326001/the-role-of-plant-processing-for-the-cancer-preventive-potential-of-ethiopian-kale-brassica-carinata
#13
Grace Akinyi Odongo, Nina Schlotz, Corinna Herz, Franziska S Hanschen, Susanne Baldermann, Susanne Neugart, Bernhard Trierweiler, Lara Frommherz, Charles M A P Franz, Benard Ngwene, Abraham Wahid Luvonga, Monika Schreiner, Sascha Rohn, Evelyn Lamy
Background: Ethiopian kale (Brassica carinata) is a horticulturally important crop used as leafy vegetable in large parts of East and Southern Africa. The leaves are reported to contain high concentrations of health-promoting secondary plant metabolites. However, scientific knowledge on their health benefits is scarce. Objective: This study aimed to determine the cancer preventive potential of B. carinata using a human liver in vitro model focusing on processing effects on the pattern of secondary plant metabolites and bioactivity...
2017: Food & Nutrition Research
https://www.readbyqxmd.com/read/28325874/ion-and-inhibitor-binding-of-the-double-ring-ion-selectivity-filter-of-the-mitochondrial-calcium-uniporter
#14
Chan Cao, Shuqing Wang, Tanxing Cui, Xun-Cheng Su, James J Chou
The calcium (Ca(2+)) uniporter of mitochondria is a holocomplex consisting of the Ca(2+)-conducting channel, known as mitochondrial calcium uniporter (MCU), and several accessory and regulatory components. A previous electrophysiology study found that the uniporter has high Ca(2+) selectivity and conductance and this depends critically on the conserved amino acid sequence motif, DXXE (Asp-X-X-Glu) of MCU. A recent NMR structure of the MCU channel from Caenorhabditis elegans revealed that the DXXE forms two parallel carboxylate rings at the channel entrance that seem to serve as the ion selectivity filter, although direct ion interaction of this structural motif has not been addressed...
March 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28323163/cerebrospinal-and-interstitial-fluid-transport-via-the-glymphatic-pathway-modeled-by-optimal-mass-transport
#15
Vadim Ratner, Yi Gao, Hedok Lee, Rena Elkin, Maiken Nedergaard, Helene Benveniste, Allen Tannenbaum
The glymphatic pathway is a system which facilitates continuous cerebrospinal fluid (CSF) and interstitial fluid (ISF) exchange and plays a key role in removing waste products from the rodent brain. Dysfunction of the glymphatic pathway may be implicated in the pathophysiology of Alzheimer's disease. Intriguingly, the glymphatic system is most active during deep wave sleep general anesthesia. By using paramagnetic tracers administered into CSF of rodents, we previously showed the utility of MRI in characterizing a macroscopic whole brain view of glymphatic transport but we have yet to define and visualize the specific flow patterns...
March 16, 2017: NeuroImage
https://www.readbyqxmd.com/read/28321699/magnetic-edta-functionalized-cofe2o4-nanoparticles-edta-cofe2o4-as-a-novel-catalyst-for-peroxymonosulfate-activation-and-degradation-of-orange-g
#16
Lin Deng, Zhou Shi, Zhiyan Zou, Shiqing Zhou
EDTA functionalized CoFe2O4 nanoparticles (EDTA-CoFe2O4) synthesized using a facile one-pot solvothermal method were employed as catalysts to activate peroxymonosulfate (PMS) with Orange G (OG) as the target pollutant. Effects of operating parameters including initial solution pH, catalyst dosage, PMS dosage, and water matrix components such as Cl(-), NO3(-), CO3(2-), and humic acid were evaluated. A degradation efficiency of 93% was achieved in 15 min with 1 mM PMS and 0.2 g/L EDTA-CoFe2O4 catalyst, while only 57% of OG was degraded within 15 min in CoFe2O4/PMS system...
March 20, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28319939/radical-scavenging-activity-of-a-sunscreen-enriched-by-antioxidants-providing-protection-in-the-whole-solar-spectral-range
#17
Carla Souza, Patrícia Maia Campos, Sabine Schanzer, Stephanie Albrecht, Silke B Lohan, Jürgen Lademann, Maxim E Darvin, Martina C Meinke
BACKGROUND/AIM: The main reason for extrinsic skin aging is the negative action of free radicals. The formation of free radicals in the skin has been associated with ultraviolet (UV) exposure and also to visible (VIS) and near-infrared (NIR) irradiations. The aim of the present study was to evaluate the efficacy of a sunscreen in the whole solar range. METHODS: The radical-scavenging activity of a sunscreen in the UV, VIS, and NIR ranges was evaluated using electron paramagnetic resonance spectroscopy...
March 21, 2017: Skin Pharmacology and Physiology
https://www.readbyqxmd.com/read/28319293/bis-gadolinium-complexes-for-solid-effect-and-cross-effect-dynamic-nuclear-polarization
#18
Monu Kaushik, Mian Qi, Adelheid Godt, Björn Corzilius
High-spin complexes act as polarizing agents (PAs) for dynamic nuclear polarization (DNP) in solid-state NMR spectroscopy and feature promising aspects towards biomolecular DNP. We present a study on bis(Gd-chelate)s which enable cross effect (CE) DNP owing to spatial confinement of two dipolar-coupled electron spins. Their well-defined Gd⋅⋅⋅Gd distances in the range of 1.2-3.4 nm allowed us to elucidate the Gd⋅⋅⋅Gd distance dependence of the DNP mechanism and NMR signal enhancement. We found that Gd⋅⋅⋅Gd distances above 2...
March 20, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28317922/optical-imaging-of-localized-chemical-events-using-programmable-diamond-quantum-nanosensors
#19
Torsten Rendler, Jitka Neburkova, Ondrej Zemek, Jan Kotek, Andrea Zappe, Zhiqin Chu, Petr Cigler, Jörg Wrachtrup
Development of multifunctional nanoscale sensors working under physiological conditions enables monitoring of intracellular processes that are important for various biological and medical applications. By attaching paramagnetic gadolinium complexes to nanodiamonds (NDs) with nitrogen-vacancy (NV) centres through surface engineering, we developed a hybrid nanoscale sensor that can be adjusted to directly monitor physiological species through a proposed sensing scheme based on NV spin relaxometry. We adopt a single-step method to measure spin relaxation rates enabling time-dependent measurements on changes in pH or redox potential at a submicrometre-length scale in a microfluidic channel that mimics cellular environments...
March 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28317908/determination-of-low-loss-in-isotopically-pure-single-crystal-28-si-at-low-temperatures-and-single-microwave-photon-energy
#20
Nikita Kostylev, Maxim Goryachev, Andrey D Bulanov, Vladimir A Gavva, Michael E Tobar
The low dielectric losses of an isotopically pure single crystal (28)Si sample were determined at a temperature of 20 mK and at powers equivalent to that of a single photon. Whispering Gallery Mode (WGM) analysis revealed large Quality Factors of order 2 × 10(6) (dielectric loss ~5 × 10(-7)) at high powers, degrading to 7 × 10(-5) (dielectric loss ~1.4 × 10(-6) at single photon energy. A very low-loss narrow line width paramagnetic spin flip transition was detected with extreme sensitivity in (28)Si, with very small concentration below 10(10) cm(-3) (less than 10 parts per trillion) and g-factor of 1...
March 20, 2017: Scientific Reports
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