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Activation theory

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https://www.readbyqxmd.com/read/28431312/melatonin-charge-transfer-complex-with-2-3-dichloro-5-6-dicyano-1-4-benzoquinone-molecular-structure-dft-studies-thermal-analyses-evaluation-of-biological-activity-and-utility-for-determination-of-melatonin-in-pure-and-dosage-forms
#1
Gehad G Mohamed, Maher M Hamed, Nadia G Zaki, Mohamed M Abdou, Marwa El-Badry Mohamed, Abanoub Mosaad Abdallah
A simple, accurate and fast spectrophotometric method for the quantitative determination of melatonin (ML) drug in its pure and pharmaceutical forms was developed based on the formation of its charge transfer complex with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as an electron acceptor. The different conditions for this method were optimized accurately. The Lambert-Beer's law was found to be valid over the concentration range of 4-100μgmL(-1) ML. The solid form of the CT complex was structurally characterized by means of different spectral methods...
April 4, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28430191/activating-lattice-oxygen-redox-reactions-in-metal-oxides-to-catalyse-oxygen-evolution
#2
Alexis Grimaud, Oscar Diaz-Morales, Binghong Han, Wesley T Hong, Yueh-Lin Lee, Livia Giordano, Kelsey A Stoerzinger, Marc T M Koper, Yang Shao-Horn
Understanding how materials that catalyse the oxygen evolution reaction (OER) function is essential for the development of efficient energy-storage technologies. The traditional understanding of the OER mechanism on metal oxides involves four concerted proton-electron transfer steps on metal-ion centres at their surface and product oxygen molecules derived from water. Here, using in situ (18)O isotope labelling mass spectrometry, we provide direct experimental evidence that the O2 generated during the OER on some highly active oxides can come from lattice oxygen...
May 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28429940/density-functional-theory-and-car-parrinello-molecular-dynamics-study-of-the-hydrogen-producing-mechanism-of-the-co-dmgbf2-2-and-co-dmgh-2-cobaloxime-complexes-in-the-acetonitrile-water-solvent
#3
Jinfan Chen, Patrick H-L Sit
The catalytic hydrogen-producing processes of two prototypical cobaloxime catalysts Co(dmgBF2)2 (dmgBF2=difluoroboryl-dimethylglyoxime) and Co(dmgH)2 (dmgH=dimethylglyoxime), were studied by Density Functional Theory (DFT) and Car-Parrinello molecular dynamics (CPMD) simulations in the explicit acetonitrile-water solvent. Our study demonstrates the key role of water molecules as shuttles to deliver protons to the cobalt active centers of these catalysts. However, the transfer of protons to the cobalt centers also competes with the diffusion of the proton away from the complex via the hydrogen bond network of water...
April 21, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28429933/remarkably-enhancing-green-excitation-efficiency-for-solar-energy-utilization-red-phosphors-ba2zns3-eu-2-x-co-doped-halide-ions-x-cl-br-i
#4
Tingting Luo, Yun Du, Zhongxian Qiu, Yanmei Li, Xiaofang Wang, Wenli Zhou, Jilin Zhang, Liping Yu, Shixun Lian
Eu(2+)-activated Ba2ZnS3 has been reported as a red phosphor with a broad emission band peaking at 650 nm under blue excitation for white-LED. In this study, Ba2ZnS3:Eu(2+), X(-) (X = F, Cl, Br, I) phosphors doped with halide ions were prepared by traditional high-temperature solid-state reaction. Phase identification of powders was performed by X-ray powder diffraction analysis, confirming the existence of single-phase Ba2ZnS3 crystals without dopant. The corresponding excitation spectra showed an additional broad band in the green region peaking at 550 nm when the phosphor was halogenated except by the smallest F(-)...
April 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28429642/selected-weight-management-interventions-for-military-populations-in-the-united-states-a-narrative-report
#5
Jessica Murray, Basil H Aboul-Enein, Joshua Bernstein, Joanna Kruk
Overweight and obesity continues to be a significant public health burden in the US and particularly among military personnel. Although the US Department of Defense mandates standardized physical activity requirements for military members, incidence and prevalence of overweight and obesity among military personnel continue to increase. Each military department controls their own interventional strategies for physical fitness and weight control. However, unique challenges such as geographic transients, lack of central standardization and empirical efficacy data across military departments, and chronic stress associated with military service adversely affect program outcomes...
January 1, 2017: Nutrition and Health
https://www.readbyqxmd.com/read/28429418/the-dynamics-of-the-reaction-of-feo-and-h2-a-model-for-inorganic-oxidation
#6
Stéphanie Essafi, David P Tew, Jeremy N Harvey
Extensive density functional theory (DFT) calculations using the B3LYP functional were used to explore the sextet and quartet energy potential energy surfaces (PESs) of the title reaction, and as a basis to fit global analytical reactive PESs. Surface-hopping dynamics on these PESs reproduce the experimentally observed reactivity and confirm that hydrogen activation rather than spin-state change is rate-limiting at low reaction energy, where the main products are Fe(+) and H2 O. A change in spin state is inefficient in the product region so that excited-state (4) Fe(+) is the dominant product...
April 21, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28428165/a-framework-for-the-study-of-complex-mhealth-interventions-in-diverse-cultural-settings
#7
Marion A Maar, Karen Yeates, Nancy Perkins, Lisa Boesch, Diane Hua-Stewart, Peter Liu, Jessica Sleeth, Sheldon W Tobe
BACKGROUND: To facilitate decision-making capacity between options of care under real-life service conditions, clinical trials must be pragmatic to evaluate mobile health (mHealth) interventions under the variable conditions of health care settings with a wide range of participants. The mHealth interventions require changes in the behavior of patients and providers, creating considerable complexity and ambiguity related to causal chains. Process evaluations of the implementation are necessary to shed light on the range of unanticipated effects an intervention may have, what the active ingredients in everyday practice are, how they exert their effect, and how these may vary among recipients or between sites...
April 20, 2017: JMIR MHealth and UHealth
https://www.readbyqxmd.com/read/28427564/inflammation-in-epileptic-encephalopathies
#8
Oleksii Shandra, Solomon L Moshé, Aristea S Galanopoulou
West syndrome (WS) is an infantile epileptic encephalopathy that manifests with infantile spasms (IS), hypsarrhythmia (in ~60% of infants), and poor neurodevelopmental outcomes. The etiologies of WS can be structural-metabolic pathologies (~60%), genetic (12%-15%), or of unknown origin. The current treatment options include hormonal treatment (adrenocorticotropic hormone and high-dose steroids) and the GABA aminotransferase inhibitor vigabatrin, while ketogenic diet can be given as add-on treatment in refractory IS...
2017: Advances in Protein Chemistry and Structural Biology
https://www.readbyqxmd.com/read/28427563/neuroinflammation-in-alzheimer-s-disease-the-preventive-and-therapeutic-potential-of-polyphenolic-nutraceuticals
#9
Yousef Sawikr, Nagendra Sastry Yarla, Ilaria Peluso, Mohammad Amjad Kamal, Gjumrakch Aliev, Anupam Bishayee
Brain inflammation, characterized by increased microglia and astrocyte activation, increases during aging and is a key feature of neurodegenerative diseases, such as Alzheimer's disease (AD). In AD, neuronal death and synaptic impairment, induced by amyloid-β (Aβ) peptide, are at least in part mediated by microglia and astrocyte activation. Glial activation results in the sustained production of proinflammatory cytokines and reactive oxygen species, giving rise to a chronic inflammatory process. Astrocytes are the most abundant glial cells in the central nervous system and are involved in the neuroinflammation...
2017: Advances in Protein Chemistry and Structural Biology
https://www.readbyqxmd.com/read/28427014/chemical-and-biological-properties-of-a-supramolecular-complex-of-tuftsin-and-cucurbit-7-uril
#10
Ekaterina A Kovalenko, Ekaterina A Pashkina, Lyubov Y Kanazhevskaya, Alexey N Masliy, Vladimir A Kozlov
Cucurbit[7]uril (CB7) is an uncharged and water-soluble macrocyclic host. CB7 binds to doubly protonated tuftsin, which is the tetrapeptide Thr-Lys-Pro-Arg, with moderate affinity (Ka=2.1×10(3)M(-1)). In this study, the host-guest complexation was confirmed by fluorescence titration. This affinity would allow for easy release of the peptide under physiological conditions. According to density functional theory calculations, the structural binding motif involves hydrogen bonding. The most energetically stable form had the Arg side chain inside the CB7 cavity...
April 17, 2017: International Immunopharmacology
https://www.readbyqxmd.com/read/28426923/potassium-promoted-molybdenum-carbide-as-a-highly-active-and-selective-catalyst-for-co2-conversion-to-co
#11
Marc D Porosoff, Jeffrey W Baldwin, Xi Peng, Giannis Mpourmpakis, Heather D Willauer
The high concentration of CO2 bound in seawater represents a significant opportunity to extract and use this CO2 as a C1 feedstock for synthetic fuels. Through an existing process patented by the U.S. Navy, CO2 and H2 can be concurrently extracted from seawater, then catalytically reacted to produce synthetic fuel. Hydrogenating CO2 directly into liquid hydrocarbons is exceptionally difficult, but by first identifying a catalyst for selective CO production via reverse water-gas shift (RWGS), CO can then be hydrogenated to fuel through Fischer-Tropsch (FT) synthesis...
April 20, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28426766/activated-entomopathogenic-nematode-infective-juveniles-release-lethal-venom-proteins
#12
Dihong Lu, Marissa Macchietto, Dennis Chang, Mirayana M Barros, James Baldwin, Ali Mortazavi, Adler R Dillman
Entomopathogenic nematodes (EPNs) are unique parasites due to their symbiosis with entomopathogenic bacteria and their ability to kill insect hosts quickly after infection. It is widely believed that EPNs rely on their bacterial partners for killing hosts. Here we disproved this theory by demonstrating that the in vitro activated infective juveniles (IJs) of Steinernema carpocapsae (a well-studied EPN species) release venom proteins that are lethal to several insects including Drosophila melanogaster. We confirmed that the in vitro activation is a good approximation of the in vivo process by comparing the transcriptomes of individual in vitro and in vivo activated IJs...
April 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28426724/cloning-retinoid-and-peroxisome-proliferator-activated-nuclear-receptors-of-the-pacific-oyster-and-in-silico-binding-to-environmental-chemicals
#13
Susanne Vogeler, Tamara S Galloway, Michail Isupov, Tim P Bean
Disruption of nuclear receptors, a transcription factor superfamily regulating gene expression in animals, is one proposed mechanism through which pollution causes effects in aquatic invertebrates. Environmental pollutants have the ability to interfere with the receptor's functions through direct binding and inducing incorrect signals. Limited knowledge of invertebrate endocrinology and molecular regulatory mechanisms, however, impede the understanding of endocrine disruptive effects in many aquatic invertebrate species...
2017: PloS One
https://www.readbyqxmd.com/read/28426536/exploring-the-interaction-between-nursing-decision-making-and-patient-outcomes-in-2-european-cancer-centers-a-qualitative-study
#14
Dario Valcarenghi, Annamaria Bagnasco, Giuseppe Aleo, Gianluca Catania, Milko Zanini, Bruno Cavaliere, Franco Carnevale, Loredana Sasso
BACKGROUND: In some clinical settings, nurses have difficulty describing the outcomes of their caring activities. Understanding the reasons for this could help nurse leaders to improve the effectiveness and visibility of nursing practice and safeguard nurses' working conditions. OBJECTIVE: The aims of this study were to understand how nurses working in 2 different adult cancer centers make healthcare decisions and assess the respective outcomes on their patients...
April 20, 2017: Cancer Nursing
https://www.readbyqxmd.com/read/28425702/oxidatively-induced-c-h-activation-at-high-valent-nickel
#15
Eugene Chong, Jeff W Kampf, Alireza Ariafard, Allan J Canty, Melanie S Sanford
This communication describes a series of oxidatively induced intramolecular arene C-H activation reactions of Ni(II) model complexes to yield Ni(IV) σ-aryl products. These reactions proceed within 10 min at room temperature, which represents among the mildest conditions reported for C-H cleavage at a Ni center. A combination of density functional theory and preliminary experimental mechanistic studies implicate a pathway involving initial 2e(-) oxidation of the Ni(II) starting materials by the F(+) transfer reagent N-fluoro-2,4,6-trimethylpyridinium triflate followed by triflate-assisted C-H cleavage at Ni(IV) to yield the products...
April 20, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28425679/soft-interactions-and-volume-exclusion-by-polymeric-crowders-can-stabilize-or-destabilize-transient-structure-in-disordered-proteins-depending-on-polymer-concentration
#16
Farai I Rusinga, David D Weis
The effects of macromolecular crowding on the transient structure of intrinsically disordered proteins is not well-understood. Crowding by biological molecules inside cells could modulate transient structure and alter IDP function. Volume exclusion theory and observations of structured proteins suggest that IDP transient structure would be stabilized by macromolecular crowding. Amide hydrogen exchange (HX) of IDPs in highly concentrated polymer solutions would provide valuable insights into IDP transient structure under crowded conditions...
April 20, 2017: Proteins
https://www.readbyqxmd.com/read/28425582/personality-immune-response-and-reproductive-success-an-appraisal-of-the-pace-of-life-syndrome-hypothesis
#17
Karine Monceau, François-Xavier Dechaume-Moncharmont, Jérôme Moreau, Camille Lucas, Rémi Capoduro, Sébastien Motreuil, Yannick Moret
The pace-of-life syndrome (POLS) hypothesis is an extended concept of the life history theory that includes behavioural traits. The studies challenging the POLS hypothesis often focus on the relationships between a single personality trait and a physiological and/or life history traits. While pathogens represent a major selective pressure, few studies have been interested in testing relationships between behavioural syndrome, and several fitness components including immunity. The aim of this study is to address this question in the mealworm beetle, Tenebrio molitor, a model species in immunity studies...
April 20, 2017: Journal of Animal Ecology
https://www.readbyqxmd.com/read/28425553/structural-control-of-side-chain-chromophores-to-achieve-highly-efficient-electro-optic-activity
#18
Yuhui Yang, Zhuo Chen, Jialei Liu, Hongyan Xiao, Zhen Zhen, Xinhou Liu, Guohua Jiang
A series of chromophores J1-J4 have been synthesized based on julolidine donors modified with different rigid steric hindrance groups. Compared with the chromophore (J1) without the isolation group, chromophores J2, J3 and J4 show better stability. Structural analysis and photophysical property measurements were carried out to compare the molecular mobility and steric hindrance effect of the different donor-modified chromophores. All of these chromophores with isolation groups showed superb thermal stabilities with high thermal decomposition temperatures above 250 °C...
April 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28425134/record-broken-a-copper-peroxide-complex-with-enhanced-stability-and-faster-hydroxylation-catalysis
#19
Sonja Herres-Pawlis, Patricia Liebhäuser, Kristina Keisers, Alexander Hoffmann, Thomas Schnappinger, Isabella Sommer, Anne Thoma, Claudia Wilfer, Roland Schoch, Kai Stührenberg, Matthias Bauer, Maximilian Dürr, Ivana Ivanovic-Burmazovic
Tyrosinase model systems pinpoint pathways to translate nature´s synthetic abilities into useful synthetic catalysts. Mostly, they use N-donor ligands which mimic the histidine residues coordinating the two copper centres. Copper complexes with bis(pyrazolyl)methanes with pyridinyl or imidazolyl moieties are already reported as excellent tyrosinase models. Substitution of the pyridinyl donor results now in the new ligand HC(3 tBuPz)2(4 CO2MePy) which stabilises a room-temperature stable -2:2-peroxide dicopper(II) species upon oxygenation...
April 19, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28424669/inferring-microbial-interactions-in-the-gut-of-the-hong-kong-whipping-frog-polypedates-megacephalus-and-a-validation-using-probiotics
#20
Francis Cheng-Hsuan Weng, Grace Tzun-Wen Shaw, Chieh-Yin Weng, Yi-Ju Yang, Daryi Wang
The concerted activity of intestinal microbes is crucial to the health and development of their host organisms. Investigation of microbial interactions in the gut should deepen our understanding of how these micro-ecosystems function. Due to advances in Next Generation Sequencing (NGS) technologies, various bioinformatic strategies have been proposed to investigate these microbial interactions. However, due to the complexity of the intestinal microbial community and difficulties in monitoring their interactions, at present there is a gap between the theory and biological application...
2017: Frontiers in Microbiology
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