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https://www.readbyqxmd.com/read/28727932/laboratory-studies-of-methane-and-its-relationship-to-prebiotic-chemistry
#1
Kensei Kobayashi, Wolf D Geppert, Nathalie Carrasco, Nils G Holm, Olivier Mousis, Maria Elisabetta Palumbo, J Hunter Waite, Naoki Watanabe, Lucy M Ziurys
To examine how prebiotic chemical evolution took place on Earth prior to the emergence of life, laboratory experiments have been conducted since the 1950s. Methane has been one of the key molecules in these investigations. In earlier studies, strongly reducing gas mixtures containing methane and ammonia were used to simulate possible reactions in the primitive atmosphere of Earth, producing amino acids and other organic compounds. Since Earth's early atmosphere is now considered to be less reducing, the contribution of extraterrestrial organics to chemical evolution has taken on an important role...
July 20, 2017: Astrobiology
https://www.readbyqxmd.com/read/28727918/rapid-sensitive-and-quantitative-detection-of-anti-peg-antibodies-by-mpeg-coated-spr-sensors
#2
Peng Zhang, Fang Sun, Hsiang-Chieh Hung, Priyesh Jain, Kasey Joanne Leger, Shaoyi Jiang
Pre-existing and induced anti-poly(ethylene glycol) (PEG) antibodies (abs) have been shown to be related with limitation of therapeutic efficacy and reduction in tolerance of several therapeutic agents. However, the current methods to detect anti-PEG abs are tedious and usually lack of quantification. A facile, rapid, sensitive and reliable technique to detect anti-PEG abs is highly desired in both research and clinic settings. In this work, we have presented a surface plasmon resonance (SPR) biosensor technique for the detection of anti-PEG abs and compared three PEG surface chemistries...
July 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28727448/extensive-survey-of-antibody-invariant-positions-for-efficient-chemical-conjugation-using-expanded-genetic-codes
#3
Akifumi Kato, Mitsuo Kuratani, Tatsuo Yanagisawa, Kazumasa Ohtake, Akiko Hayashi, Yoshimi Amano, Kaname Kimura, Shigeyuki Yokoyama, Kensaku Sakamoto, Yasuhisa Shiraishi
The site-specific chemical conjugation of proteins, following synthesis with an expanded genetic code, promises to advance antibody-based technologies, including antibody drug conjugation and the creation of bispecific Fab dimers. The incorporation of non-natural amino acids into antibodies not only guarantees site specificity but also allows the use of bio-orthogonal chemistry. However, the efficiency of amino acid incorporation fluctuates significantly among different sites, thereby hampering the identification of useful conjugation sites...
July 20, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28727433/the-53rd-north-american-chemical-residue-workshop
#4
Brian David Eitzer, Sherry T Garris, Joan M Stevens
The 53rd North American Chemical Residue Workshop was held in July 2016. This is a brief review of the workshop including the awarding of the 2nd NACRW Excellence award to Dr. Andre de Kok. It is also an introduction to a special issue of the Journal of Agricultural and Food Chemistry that presents manuscripts of papers presented at that workshop.
July 20, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28727218/altered-sediment-biota-and-lagoon-habitat-carbonate-dynamics-due-to-sea-cucumber-bioturbation-in-a-high-pco2-environment
#5
Kennedy Wolfe, Francisco Vidal-Ramirez, Sophie Dove, Dione Deaker, Maria Byrne
The effects of global change on biological systems and functioning are already measureable, but how ecological interactions are being altered is poorly understood. Ecosystem resilience is strengthened by ecological functionality, which depends on trophic interactions between key species and resilience generated through biogenic buffering. Climate-driven alterations to coral reef metabolism, structural complexity and biodiversity are well documented, but the feedbacks between ocean change and trophic interactions of non-coral invertebrates are understudied...
July 20, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28727178/tailored-band-gaps-in-sulphur-and-nitrogen-containing-porous-donor-acceptor-polymers-snps
#6
Dana Schwarz, Yaroslav S Kochergin, Amitava Acharja, Arun Ichangi, Maksym V Opanasenko, Jiří Čejka, Uwe Lappan, Pal Arki, Junjie He, Johannes Schmidt, Petr Nachtigall, Arne Thomas, Michael Janus Bojdys
Donor-acceptor dyads hold the key to tuning of electrochemical properties and enhanced mobility of charge carriers, yet their incorporation into a heterogeneous polymer network proves difficulty due to the fundamentally different chemistry of the donor- and acceptor-subunits. We present a family of sulphur and nitrogen containing porous polymers (SNPs) that are obtained via Sonogashira-Hagihara cross-coupling and that combine electron-withdrawing triazine (C3N3) and electron donating, sulphur-containing linkers...
July 20, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28726953/4-4-di-tert-butyl-6-1h-tetrazol-5-yl-2-2-bipyridine-modification-of-a-highly-selective-n-donor-ligand-for-the-separation-of-trivalent-actinides-from-lanthanides
#7
Martin M Maiwald, Anna T Wagner, Jochen Kratsch, Andrej Skerencak-Frech, Michael Trumm, Andreas Geist, Peter W Roesky, Petra J Panak
In the present work, the complexation and extraction behaviour of 4,4'di-tert-butyl-6-(1H-tetrazol-5-yl)-2,2'-bipyridine (HN4(t)bubipy) towards trivalent actinides (An(iii)) and lanthanides (Ln(iii)) is studied by spectroscopic methods, liquid-liquid extraction, and quantum chemical calculations. The ligand synthesis of HN4(t)bubipy as well as its application in coordination chemistry of the 4f elements is described. Reaction of HN4(t)bubipy with [Ln(NO3)3·6H2O] (Ln = Sm, Eu) results in [H2N4(t)bubipy](+)[Ln(N4(t)bubipy)(NO3)3(H2O)](-)...
July 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28726949/spin-reversal-energy-barriers-of-305-k-for-fe-2-d-6-ions-with-linear-ligand-coordination
#8
Lei Xu, Ziba Zangeneh, Ravi Yadav, Stanislav Avdoshenko, Jeroen van den Brink, Anton Jesche, Liviu Hozoi
A remarkably large magnetic anisotropy energy of 305 K is computed by quantum chemistry methods for divalent Fe(2+) d(6) substitutes at Li-ion sites with D6h point-group symmetry within the solid-state matrix of Li3N. This is similar to values calculated by the same approach and confirmed experimentally for linearly coordinated monovalent Fe(1+) d(7) species, among the largest so far in the research area of single-molecule magnets. Our ab initio results therefore mark a new exciting exploration path in the search for superior single-molecule magnets, rooted in the configuration of d(6) transition-metal ions with linear or quasilinear nearest-neighbor coordination...
July 20, 2017: Nanoscale
https://www.readbyqxmd.com/read/28726825/materials-science-chemistry-and-physics-happily-wed
#9
Gregory A Fiete
No abstract text is available yet for this article.
July 19, 2017: Nature
https://www.readbyqxmd.com/read/28726818/topological-quantum-chemistry
#10
Barry Bradlyn, L Elcoro, Jennifer Cano, M G Vergniory, Zhijun Wang, C Felser, M I Aroyo, B Andrei Bernevig
Since the discovery of topological insulators and semimetals, there has been much research into predicting and experimentally discovering distinct classes of these materials, in which the topology of electronic states leads to robust surface states and electromagnetic responses. This apparent success, however, masks a fundamental shortcoming: topological insulators represent only a few hundred of the 200,000 stoichiometric compounds in material databases. However, it is unclear whether this low number is indicative of the esoteric nature of topological insulators or of a fundamental problem with the current approaches to finding them...
July 19, 2017: Nature
https://www.readbyqxmd.com/read/28726691/an-exploratory-study-of-the-effects-of-stormwater-pipeline-materials-on-transported-stormwater-quality
#11
Matthias Borris, Heléne Österlund, Jiri Marsalek, Maria Viklander
Implications of three sewer pipe materials (concrete, galvanized corrugated steel, and polyvinyl chloride (PVC)) for stormwater quality were explored in laboratory experiments, in which three types of stormwater, SW1-SW3, were circulated in 0.5 m long sewer pipe sections. SW1 and SW2 represented synthetic rainwater, without and with fine street sediment added (CTSS = 150 mg/L), respectively, and SW3 was actual stormwater with the same sediment addition as SW2. Following 20-min runs, with an equivalent distance of 500 m travelled by water particles, a number of statistically significant changes in the stormwater chemistry were observed: (i) pH of all the simulated stormwaters increased in the concrete pipe (from 7...
July 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/28726386/a-smart-biointerface-with-photoswitched-functions-between-bactericidal-activity-and-bacteria-releasing-ability
#12
Ting Wei, Wenjun Zhan, Qian Yu, Hong Chen
Smart biointerfaces with capability to regulate cell-surface interactions in response to external stimuli are of great interest for both fundamental research and practical applications. Smart surfaces with "ON/OFF" switchability for a single function such as cell attachment/detachment are well-known and useful, but the ability to switch between two different functions may be seen as the next level of "smart". In this work reported, a smart supramolecular surface capable of switching functions reversibly between bactericidal activity and bacteria-releasing ability in response to UV-visible light is developed...
July 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28726382/interparticle-reactions-an-emerging-direction-in-nanomaterials-chemistry
#13
K R Krishnadas, Ananya Baksi, Atanu Ghosh, Ganapati Natarajan, Anirban Som, Thalappil Pradeep
Nanoparticles exhibit a rich variety in terms of structure, composition, and properties. However, reactions between them remain largely unexplored. In this Account, we discuss an emerging aspect of nanomaterials chemistry, namely, interparticle reactions in solution phase, similar to reactions between molecules, involving atomically precise noble metal clusters. A brief historical account of the developments, starting from the bare, gas phase clusters, which led to the synthesis of atomically precise monolayer protected clusters in solution, is presented first...
July 20, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28726177/the-reliability-paradox-why-robust-cognitive-tasks-do-not-produce-reliable-individual-differences
#14
Craig Hedge, Georgina Powell, Petroc Sumner
Individual differences in cognitive paradigms are increasingly employed to relate cognition to brain structure, chemistry, and function. However, such efforts are often unfruitful, even with the most well established tasks. Here we offer an explanation for failures in the application of robust cognitive paradigms to the study of individual differences. Experimental effects become well established - and thus those tasks become popular - when between-subject variability is low. However, low between-subject variability causes low reliability for individual differences, destroying replicable correlations with other factors and potentially undermining published conclusions drawn from correlational relationships...
July 19, 2017: Behavior Research Methods
https://www.readbyqxmd.com/read/28725901/zinc-binding-sites-in-pra1-a-zincophore-from-candida-albicans
#15
Dorota Łoboda, Magdalena Rowińska-Żyrek
The aim of this work is to understand the interactions of Zn(ii) with Pra1, a zincophore from Candida albicans, one of the most common causes of serious fungal infections in humans. Pra1 is a 299 amino acid protein, secreted from the fungus to specifically bind Zn(ii) and deliver it to a transmembrane zinc transporter, Zrt1. We take the first step towards understanding the bioinorganic chemistry of this process, by pointing out the Zn(ii) binding sites in Pra1 and understanding the thermodynamics of such interactions...
July 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28725094/evolution-of-three-nobel-prize-themes-and-a-nobel-snub-theme-in-chemistry-a-bibliometric-study-with-focus-on-international-collaboration
#16
Sichao Tong, Per Ahlgren
In this study, three chemistry research themes closely associated with the Nobel Prize are bibliometrically analyzed-Ribozyme, Ozone and Fullerene-as well as a research theme in chemistry not associated with the Nobel Prize (a Nobel snub theme): Brunauer-Emmett-Teller equation. We analyze, based on an algorithmically constructed publication-level classification system, the evolution of the four themes with respect to publication volume and international collaboration, using two datasets, one of them a subset of highly cited publications, for each considered time period...
2017: Scientometrics
https://www.readbyqxmd.com/read/28725039/surface-chemistry-and-germination-improvement-of-quinoa-seeds-subjected-to-plasma-activation
#17
A Gómez-Ramírez, C López-Santos, M Cantos, J L García, R Molina, J Cotrino, J P Espinós, A R González-Elipe
Plasma treatment is recognized as a suitable technology to improve germination efficiency of numerous seeds. In this work Quinoa seeds have been subjected to air plasma treatments both at atmospheric and low pressure and improvements found in germination rate and percentage of success. Seed water uptake by exposure to water vapor, although slightly greater for plasma treated seeds, did not justify the observed germination improvement. To identify other possible factors contributing to germination, the chemical changes experienced by outer parts of the seed upon plasma exposure have been investigated by X-ray photoemission spectroscopy (XPS) and scanning electron microscopy (SEM-EDX)...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28724752/the-fluid-mechanics-of-transcatheter-heart-valve-leaflet-thrombosis-in-the-neo-sinus
#18
Prem A Midha, Vrishank Raghav, Rahul Sharma, Jose F Condado, Ikechukwu U Okafor, Tanya Rami, Gautam Kumar, Vinod H Thourani, Hasan Jilaihawi, Vasilis Babaliaros, Raj R Makkar, Ajit P Yoganathan
Background -Transcatheter heart valve (THV) thrombosis has been increasingly reported. In these studies, thrombus quantification has been based on 2D assessment of a 3D phenomenon. Methods -Post-procedural four-dimensional, volume-rendered CT (4DCT) data of CoreValve, Evolut R, and SAPIEN 3 transcatheter aortic valve replacement (TAVR) patients enrolled in the RESOLVE trial were included in this analysis. Patients on anticoagulation were excluded. SAPIEN 3 and CoreValve/Evolut R patients with and without hypo-attenuated leaflet thickening (HALT) were included in order to study differences between groups...
July 19, 2017: Circulation
https://www.readbyqxmd.com/read/28724692/enhancing-studies-of-pharmacodynamic-mechanisms-via-measurements-of-metabolic-flux
#19
Natalie A Daurio, Sheng-Ping Wang, Ying Chen, Haihong Zhou, David G McLaren, Thomas P Roddy, Douglas G Johns, Denise Milot, Takhar Kasumov, Mark D Erion, David E Kelley, Stephen F Previs
Drug discovery and development efforts are largely based around a common expectation, namely, direct or indirect action on a cellular process (e.g. statin-mediated enzyme inhibition or insulin-stimulated receptor activation) will have a beneficial impact on physiological homeostasis. To expand on this, one could argue that virtually all pharmacological interventions attempt to influence the flow of traffic in a biochemical network, irrespective of disease or modality. Since stable isotope tracer kinetic methods provide a measure of traffic flow (i...
July 19, 2017: Journal of Pharmacology and Experimental Therapeutics
https://www.readbyqxmd.com/read/28724560/accurate-detection-of-methicillin-resistant-staphylococcus-aureus-in-mixtures-utilizing-single-bacterial-duplex-droplet-digital-pcr
#20
Jun Luo, Junhua Li, Hang Yang, Junping Yu, Hongping Wei
Accurate and rapid identification of methicillin-resistant Staphylococcus aureus (MRSA) is needed to screen MRSA carriers and improve treatment. The current widely used duplex PCR methods are not able to differentiate MRSA from the co-existence of methicillin-susceptible S. aureus (MSSA) and other methicillin-resistant Staphylococci In this study, we aimed to develop a direct method for accurate and rapid detection of MRSA in clinical samples from open environments, such as nasal swab. The new molecular assay is based on detecting the co-occurrence of nuc and mecA markers in a single bacterial cell by utilizing droplet digital PCR (ddPCR) with a chimeric lysin ClyH for cell lysis...
July 19, 2017: Journal of Clinical Microbiology
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