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https://www.readbyqxmd.com/read/28651044/the-atmospheric-fate-of-monoethanolamine-enhancing-new-particle-formation-of-sulfuric-acid-as-an-important-removal-process
#1
Hong-Bin Xie, Jonas Elm, Roope Halonen, Nanna Myllys, Theo Kurtén, Markku Kulmala, Hanna Vehkamaki
Monoethanolamine (MEA), a potential atmospheric pollutant from capture unit of a leading CO2 capture technology, could be removed by participating H2SO4-based new particle formation (NPF) as simple amines. Here we evaluated the enhancing potential of MEA on H2SO4-based NPF by examining the formation of molecular clusters of MEA and H2SO4 using a combined quantum chemistry calculations and kinetics modeling. The results indicate that MEA at ppt-level can enhance H2SO4-based NPF. The enhancing potential of MEA is < dimethylamine (DMA), one of the strongest enhancing agents, and ≫ methylamine (MA), in contrast to the order suggested solely by their basicity (MEA < MA < DMA)...
June 26, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28650640/light-mediated-reactive-oxygen-species-generation-and-iron-redox-transformations-in-the-presence-of-exudate-from-the-cyanobacterium-microcystis-aeruginosa
#2
Kai Wang, Shikha Garg, T David Waite
The photochemical properties of the organic exudate secreted by a toxic strain of Microcystis aeruginosa were studied by measuring reactive oxygen species (ROS) generation and redox transformations of iron in the presence of the organic exudate under acidic (pH 4) and alkaline (pH 8) conditions. Our results show that the organic exudate generates nanomolar concentrations of superoxide and hydrogen peroxide on irradiation with simulated sunlight in a manner consistent with that reported for terrigenous natural organic matter...
June 26, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28650621/novel-cdta-based-bifunctional-chelators-for-stable-and-inert-mn-ii-complexation-synthesis-and-physicochemical-characterization
#3
Christian Vanasschen, Enikő Molnár, Gyula Tircsó, Ferenc K Kálmán, Éva Tóth, Marie Brandt, Heinz H Coenen, Bernd Neumaier
In the search for Mn(II) MR and PET/MR imaging agents with optimal balance between thermodynamic stability, kinetic inertness, and relaxivity, two novel bifunctional Mn(II) chelators (BFMnCs) based on CDTA (trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid) were synthesized. A six-step synthesis, involving the buildup of a functionalized trans-1,2-diaminocyclohexane core, provided CuAAC-reactive 6a and 6b bearing an alkyne or azide substituent on the cyclohexane ring, respectively (CuAAC = Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition)...
June 26, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28650617/kinetics-and-mechanism-of-the-autocatalytic-oxidation-of-bis-terpyridine-iron-ii-by-peroxomonosulfate-ion-oxone-in-acidic-medium
#4
Gábor Bellér, Gábor Lente, István Fábián
The autocatalytic oxidation of the bis(terpyridine)iron(II) complex, Fe(tpy)2(2+) by peroxomonosulfate ion (PMS) proceeds via the formation of the corresponding iron(III) complex (Fe(tpy)2(3+)) as the primary oxidation product. The proton-assisted dissociation of Fe(tpy)2(2+) and subsequent oxidation of Fe(2+) are side reactions in this system. In the initial stage of the reaction, a 1:1 adduct is formed between PMS and bis(terpyridine)iron(II), which decomposes in an intramolecular electron transfer reaction step...
June 26, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28650154/interrogating-detergent-desolvation-of-nanopore-forming-proteins-by-fluorescence-polarization-spectroscopy
#5
Aaron J Wolfe, Yi-Ching Hsueh, Adam R Blanden, Mohammad M Mohammad, Bach Pham, Avinash Kumar Thakur, Stewart N Loh, Min Chen, Liviu Movileanu
Understanding how membrane proteins interact with detergents is of fundamental and practical significance in structural and chemical biology as well as in nanobiotechnology. Current methods for inspecting protein-detergent complex (PDC) interfaces require high concentrations of protein and are of low throughput. Here, we describe a scalable, spectroscopic approach that uses nanomolar protein concentrations in native solutions. This approach, which is based on steady-state fluorescence polarization (FP) spectroscopy, kinetically resolves the dissociation of detergents from membrane proteins and protein unfolding...
June 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28647281/serotonergic-modulation-of-nicotine-induced-kinetic-tremor-in-mice
#6
Naofumi Kunisawa, Higor A Iha, Yuji Nomura, Misaki Onishi, Nami Matsubara, Saki Shimizu, Yukihiro Ohno
We previously demonstrated that nicotine elicited kinetic tremor by elevating the neural activity of the inferior olive via α7 nicotinic acetylcholine (nACh) receptors. Since α7 nACh receptors reportedly facilitate synaptic monoamine release, we explored the role of 5-HT receptors in induction and/or modulation of nicotine tremor. Treatment of mice with nicotine induced kinetic tremor that normally appeared during movement. The 5-HT1A agonist, 8-hydroxydipropylaminotetraline (8-OH-DPAT), significantly enhanced nicotine-induced tremor and the action of 8-OH-DPAT was antagonized by WAY-100135 (5-HT1A antagonist)...
June 9, 2017: Journal of Pharmacological Sciences
https://www.readbyqxmd.com/read/28644001/an-evaluation-of-multivalent-cation-insertion-in-single-and-double-layered-polymorphs-of-v2o5
#7
Abhishek Parija, David Prendergast, Sarbajit Banerjee
Multivalent intercalation batteries have the potential to circumvent several fundamental limitations of reigning Li-ion technologies. Such batteries will potentially deliver high volumetric energy densities, be safer to operate, and rely on materials that are much more abundant than Li in the earth's crust. The design of intercalation cathodes for such batteries requires consideration of thermodynamic aspects such as structural distortions and energetics as well as kinetic aspects such as barriers to the diffusion of cations...
June 23, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28641819/dynamic-contrast-enhanced-mr-imaging-of-carotid-vasa-vasorum-in-relation-to-coronary-and-cerebrovascular-events
#8
Juan Wang, Huijun Chen, Jie Sun, Daniel S Hippe, Huawei Zhang, Shengyuan Yu, Jianming Cai, Leixing Xie, Bao Cui, Chun Yuan, Xihai Zhao, Weimin Yuan, Hongbin Liu
BACKGROUND AND AIMS: Dynamic contrast-enhanced MR imaging (DCE-MRI) provides a noninvasive approach to the functional status of carotid adventitial vasa vasorum. Contrast extravasation rate, or K(trans), derived from kinetic modeling of adventitial enhancement, has been correlated with plaque neovascularization and inflammation. This study sought to clarify the clinical implications of K(trans) by evaluating its relationship with documented cardiovascular events (CVE). METHODS: Seventy patients with carotid plaque at clinical ultrasound examination were recruited and imaged with a previously-described bright-blood DCE-MRI protocol (spatial resolution: 0...
June 3, 2017: Atherosclerosis
https://www.readbyqxmd.com/read/28641812/continuum-based-models-and-concepts-for-the-transport-of-nanoparticles-in-saturated-porous-media-a-state-of-the-science-review
#9
REVIEW
Peyman Babakhani, Jonathan Bridge, Ruey-An Doong, Tanapon Phenrat
Environmental applications of nanoparticles (NP) increasingly result in widespread NP distribution within porous media where they are subject to various concurrent transport mechanisms including irreversible deposition, attachment/detachment (equilibrium or kinetic), agglomeration, physical straining, site-blocking, ripening, and size exclusion. Fundamental research in NP transport is typically conducted at small scale, and theoretical mechanistic modeling of particle transport in porous media faces challenges when considering the simultaneous effects of transport mechanisms...
June 7, 2017: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28641424/the-role-of-multivalency-in-the-association-kinetics-of-patchy-particle-complexes
#10
Arthur C Newton, Jan Groenewold, Willem K Kegel, Peter G Bolhuis
Association and dissociation of particles are elementary steps in many natural and technological relevant processes. For many such processes, the presence of multiple binding sites is essential. For instance, protein complexes and regular structures such as virus shells are formed from elementary building blocks with multiple binding sites. Here we address a fundamental question concerning the role of multivalency of binding sites in the association kinetics of such complexes. Using single replica transition interface sampling simulations, we investigate the influence of the multivalency on the binding kinetics and the association mechanism of patchy particles that form polyhedral clusters...
June 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28640290/intrinsic-37-35-cl-and-18-16-o-isotope-shifts-in-195-pt-and-103-rh-nmr-of-purely-inorganic-pt-and-rh-complexes-as-unique-spectroscopic-fingerprints-for-unambiguous-assignment-of-structure
#11
Klaus R Koch, Leon Engelbrecht
Well-resolved intrinsic (1)ΔM((37/35)Cl) and (1)ΔM((18/16)O) isotope shifts (where M = (195)Pt or (103)Rh) are visible in the (195)Pt NMR peak profiles of relatively kinetically inert [PtCln(H2O)6-n](4-n) (n = 1-6) complexes, their corresponding hydroxido [PtCl6-n(OH)n](2-) (n = 1-5/6) anions, and [RhCln(H2O)6-n](3-n) (n = 3-6) complexes in aqueous solutions at ca. 293 K. Although some such isotope effects have been previously reported, there are very limited published data in the open literature, and the first systematic studies of such intrinsic (1)ΔM((37/35)Cl) and (1)ΔM((18/16)O) isotope effects are reviewed in this perspective...
June 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28637762/differential-requirement-of-human-cytomegalovirus-ul112-113-protein-isoforms-for-viral-replication
#12
Tim Schommartz, Jiajia Tang, Rebekka Brost, Wolfram Brune
The UL112-113 gene is one of the few alternatively spliced genes of human cytomegalovirus (HCMV). It codes for four phosphoproteins, p34, p43, p50, and p84, all of which are expressed with early kinetics and accumulate at sites of viral DNA replication within the host cell nucleus. Although these proteins are known to play important, possibly essential, roles in the viral replication cycle, little is known about the contribution of individual UL112-113 protein products. Here we used splice site mutagenesis, intron deletion and substitution, and nonsense mutagenesis to prevent the individual expression of each UL112-113 protein isoform and to investigate the importance of each isoform for viral replication...
June 21, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28636641/development-of-a-range-of-fluorescent-reagentless-biosensors-for-atp-based-on-malonyl-coenzyme-a-synthetase
#13
Renée Vancraenenbroeck, Simone Kunzelmann, Martin R Webb
The range of ATP concentrations that can be measured with a fluorescent reagentless biosensor for ATP has been increased by modulating its affinity for this analyte. The ATP biosensor is an adduct of two tetramethylrhodamines with MatB from Rhodopseudomonas palustris. Mutations were introduced into the binding site to modify ATP binding affinity, while aiming to maintain the concomitant fluorescence signal. Using this signal, the effect of mutations in different parts of the binding site was measured. This mutational analysis revealed three variants in particular, each with a single mutation in the phosphate-binding loop, which had potentially beneficial changes in ATP binding properties but preserving a fluorescence change of ~3-fold on ATP binding...
2017: PloS One
https://www.readbyqxmd.com/read/28635263/crystalline-nanochannels-with-pendant-azobenzene-groups-steric-or-polar-effects-on-gas-adsorption-and-diffusion
#14
Hubiao Huang, Hiroshi Sato, Takuzo Aida
An azobenzene-containing, zirconium-based metal-organic framework ((Azo)MOF), upon irradiation with ultraviolet (UV) light at 365 ± 10 nm, underwent trans-to-cis isomerization of its azobenzene pendants to furnish the cis-isomer content of 21% ((Azo)MOF(21%)) in 30 min at the photostationary state and underwent backward isomerization into (Azo)MOF(1%) upon either irradiation with visible light (420-480 nm) or heating. When the cis-isomer content increased, the diffusion rate and amount of CO2 adsorbed into the nanochannels of (Azo)MOF decreased considerably...
June 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28631792/nanoscopic-dynamics-of-bicontinous-microemulsions-effect-of-membrane-associated-protein
#15
V K Sharma, Douglas G Hayes, Volker S Urban, Hugh M O'Neill, M Tyagi, E Mamontov
Bicontinous microemulsions (BμE) generally consist of nanodomains formed by surfactant in a mixture of water and oil at nearly equal proportions and are potential candidates for the solubilization and purification of membrane proteins. Here we present the first time report of nanoscopic dynamics of surfactant monolayers within BμEs formed by the anionic surfactant sodium dodecyl sulfate (SDS) measured on the nanosecond to picosecond time scale using quasielastic neutron scattering (QENS). BμEs investigated herein consisted of middle phases isolated from Winsor-III microemulsion systems that were formed by mixing aqueous and oil solutions under optimal conditions...
June 20, 2017: Soft Matter
https://www.readbyqxmd.com/read/28630701/evaluation-of-an-in-vitro-fibre-fermentation-method-using-feline-faecal-inocula-inter-individual-variation
#16
Guido Bosch, Lisa Heesen, Karine de Melo Santos, John W Cone, Wilbert F Pellikaan, Wouter H Hendriks
The present study aimed to evaluate the inter-individual variability in fermentation of standard fibrous substrates by faecal inocula from ten healthy adult female cats. Substrates were citrus pectin (CP), fructo-oligosaccharides (FOS), guar gum (GG), sugar beet pulp (SBP) and wheat middlings (WM). Each substrate was incubated with faecal inoculum from each cat. Gas production was measured continuously during the 48 h incubation and SCFA and organic matter disappearance (only SBP and WM) after incubation. Out of ten cats, nine produced faeces on the days of inoculum preparation...
2017: Journal of Nutritional Science
https://www.readbyqxmd.com/read/28630473/impact-of-antigen-density-on-the-binding-mechanism-of-igg-antibodies
#17
Maya Hadzhieva, Anastas D Pashov, Srinivas Kaveri, Sébastien Lacroix-Desmazes, Hugo Mouquet, Jordan D Dimitrov
The density and distribution pattern of epitopes at the surface of pathogens have a profound impact on immune responses. Although multiple lines of evidence highlight the significance of antigen surface density for antibody binding, a quantitative description of its effect on recognition mechanisms is missing. Here, we analyzed binding kinetics and thermodynamics of six HIV-1 neutralizing antibodies as a function of the surface density of envelope glycoprotein gp120. Antibodies that recognize gp120 with low to moderate binding affinity displayed the most pronounced sensitivity to variation in antigen density, with qualitative and substantial quantitative changes in the energetics of the binding process as revealed by non-equilibrium and equilibrium thermodynamic analyses...
June 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28630348/analysis-of-a-dual-domain-phosphoglycosyl-transferase-reveals-a-ping-pong-mechanism-with-a-covalent-enzyme-intermediate
#18
Debasis Das, Petr Kuzmic, Barbara Imperiali
Phosphoglycosyl transferases (PGTs) are integral membrane proteins with diverse architectures that catalyze the formation of polyprenol diphosphate-linked glycans via phosphosugar transfer from a nucleotide diphosphate-sugar to a polyprenol phosphate. There are two PGT superfamilies that differ significantly in overall structure and topology. The polytopic PGT superfamily, represented by MraY and WecA, has been the subject of many studies because of its roles in peptidoglycan and O-antigen biosynthesis. In contrast, less is known about a second, extensive superfamily of PGTs that reveals a core structure with dual domain architecture featuring a C-terminal soluble globular domain and a predicted N-terminal membrane-associated domain...
June 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28630316/recombinant-silicateins-as-model-biocatalysts-in-organosiloxane-chemistry
#19
S Yasin Tabatabaei Dakhili, Stephanie A Caslin, Abayomi S Faponle, Peter Quayle, Sam P de Visser, Lu Shin Wong
The family of silicatein enzymes from marine sponges (phylum Porifera) is unique in nature for catalyzing the formation of inorganic silica structures, which the organisms incorporate into their skeleton. However, the synthesis of organosiloxanes catalyzed by these enzymes has thus far remained largely unexplored. To investigate the reactivity of these enzymes in relation to this important class of compounds, their catalysis of Si-O bond hydrolysis and condensation was investigated with a range of model organosilanols and silyl ethers...
June 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28630093/dendritic-cell-sensing-of-hydrophobic-di-and-triacylated-lipopeptides-self-assembled-within-synthetic-virus-like-particles
#20
Rajni Sharma, Arin Ghasparian, John A Robinson, Kenneth C McCullough
Dendritic cells (DCs) play critical roles in developing immune defenses. One important aspect is interaction with pathogen-associated molecular patterns (PAMPs)/danger-associated molecular patterns, including di- and triacylated lipopeptides. Isolated or synthetic lipopeptides are potent vaccine adjuvants, interacting with cell surface TLR2 heterodimers. In contrast, deep embedment within bacteria cell walls would impair lipopeptide interaction with cell surface TLR2, requiring degradation for PAMP recognition...
June 19, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
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