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Chemical evolution

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https://www.readbyqxmd.com/read/28106741/the-role-of-lipid-membranes-in-life-s-origin
#1
REVIEW
David Deamer
At some point in early evolution, life became cellular. Assuming that this step was required for the origin of life, there would necessarily be a pre-existing source of amphihilic compounds capable of assembling into membranous compartments. It is possible to make informed guesses about the properties of such compounds and the conditions most conducive to their self-assembly into boundary structures. The membranes were likely to incorporate mixtures of hydrocarbon derivatives between 10 and 20 carbons in length with carboxylate or hydroxyl head groups...
January 17, 2017: Life
https://www.readbyqxmd.com/read/28106187/layer-separable-and-gap-tunable-topological-insulators
#2
Kai-Wei Chang, Wei Ji, Chao-Cheng Kaun
The way in which states of a topological insulator (TI) transform from monolayer to bulk is an important issue for applications in spintronics. However, unlike graphite, most layered materials are difficult to exfoliate. Using first-principles calculations, we predict that thallium selenide (TlSe) will be a layered TI with rather weak interlayer coupling and thus it should be exfoliated easily. The evolution of the topological states can also be driven by doping with indium (In) atoms or applying lateral strains...
January 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28106164/diverse-strategies-of-o2-usage-for-preventing-photo-oxidative-damage-under-co2-limitation-during-algal-photosynthesis
#3
Ginga Shimakawa, Yusuke Matsuda, Kensuke Nakajima, Masahiro Tamoi, Shigeru Shigeoka, Chikahiro Miyake
Photosynthesis produces chemical energy from photon energy in the photosynthetic electron transport and assimilates CO2 using the chemical energy. Thus, CO2 limitation causes an accumulation of excess energy, resulting in reactive oxygen species (ROS) which can cause oxidative damage to cells. O2 can be used as an alternative energy sink when oxygenic phototrophs are exposed to high light. Here, we examined the responses to CO2 limitation and O2 dependency of two secondary algae, Euglena gracilis and Phaeodactylum tricornutum...
January 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28103106/low-temperature-alkaline-ph-hydrolysis-of-oxygen-free-titan-tholins-carbonates-impact
#4
Coralie Brassé, Arnaud Buch, Patrice Coll, François Raulin
Titan, the largest moon of Saturn, is one of the key planetary objects in the field of exobiology. Its dense, nitrogen-rich atmosphere is the site of important organic chemistry. This paper focuses on the organic aerosols produced in Titan's atmosphere that play an important role in atmospheric and surface processes and in organic chemistry as it applies to exobiological interests. To produce reliable laboratory analogues of these aerosols, we developed, tested, and optimized a device for the synthesis of clean tholins...
January 2017: Astrobiology
https://www.readbyqxmd.com/read/28102938/low-energy-catalytic-electrolysis-for-simultaneously-hydrogen-evolution-and-lignin-depolymerization
#5
Xu Du, Wei Liu, Zhe Zhang, Arie Mulyadi, Alex Brittain, Jian Gong, Yulin Deng
Hereby we present a novel proton exchange membrane (PEM) electrolysis process in which lignin was used as the hydrogen source at anode for hydrogen production. Either polyoxometalate (POM) or FeCl3 was used as the catalysts and charge transfer agents in anode. Over 90% Faraday efficiency was achieved. In a thermal insulation reactor, the heat energy can be maintained at a very low stage for continuous operation. Compared to the best alkaline water electrolysis reported in literature, the electrical energy consumption could be 40% lower with novel lignin electrolysis method...
January 19, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28101986/size-dependent-activity-of-palladium-nanoparticles-pd-nps-efficient-conversion-of-co2-into-formate-at-low-overpotentials
#6
Motiar Rahaman, Abhijit Dutta, Peter Broekmann
We report a remarkable size-dependent activity of palladium nanoparticles towards formate production at very low overpotentials (-0.1 V to -0.5 V vs RHE). Size-selective Pd-NPs have been chemically synthesized in the range from 3.8nm to 10.7nm. Electrochemical CO₂ reduction reaction was carried out in aqueous 0.5M NaHCO₃ solution. The Faradaic efficiency of formate production (FE/formate) exceeds more than 86% at E = -0.1 V vs RHE on 3.8nm Pd-NPs whereas on 6.5 nm Pd-NPs an even higher FEformate of 98% is observed...
January 19, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28099529/a-possible-role-of-the-full-length-nascent-protein-in-post-translational-ribosome-recycling
#7
Debasis Das, Dibyendu Samanta, Arpita Bhattacharya, Arunima Basu, Anindita Das, Jaydip Ghosh, Abhijit Chakrabarti, Chanchal Das Gupta
Each cycle of translation initiation in bacterial cell requires free 50S and 30S ribosomal subunits originating from the post-translational dissociation of 70S ribosome from the previous cycle. Literature shows stable dissociation of 70S from model post-termination complexes by the concerted action of Ribosome Recycling Factor (RRF) and Elongation Factor G (EF-G) that interact with the rRNA bridge B2a/B2b joining 50S to 30S. In such experimental models, the role of full-length nascent protein was never considered seriously...
2017: PloS One
https://www.readbyqxmd.com/read/28096397/correction-for-roberts-et-al-evolution-of-south-atlantic-density-and-chemical-stratification-across-the-last-deglaciation
#8
(no author information available yet)
No abstract text is available yet for this article.
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28096368/elemental-sulfur-aerosol-forming-mechanism
#9
Manoj Kumar, Joseph S Francisco
Elemental sulfur aerosols are ubiquitous in the atmospheres of Venus, ancient Earth, and Mars. There is now an evolving body of evidence suggesting that these aerosols have also played a role in the evolution of early life on Earth. However, the exact details of their formation mechanism remain an open question. The present theoretical calculations suggest a chemical mechanism that takes advantage of the interaction between sulfur oxides, SOn (n = 1, 2, 3) and hydrogen sulfide (nH2S), resulting in the efficient formation of a Sn+1 particle...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28095316/rewiring-protein-synthesis-from-natural-to-synthetic-amino-acids
#10
REVIEW
Yongqiang Fan, Christopher R Evans, Jiqiang Ling
BACKGROUND: The protein synthesis machinery uses 22 natural amino acids as building blocks that faithfully decode the genetic information. Such fidelity is controlled at multiple steps and can be compromised in nature and in the laboratory to rewire protein synthesis with natural and synthetic amino acids. SCOPE OF REVIEW: This review summarizes the major quality control mechanisms during protein synthesis, including aminoacyl-tRNA synthetases, elongation factors, and the ribosome...
January 14, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28094816/methylation-specific-targeting-of-a-chromatin-remodeling-complex-from-sponges-to-humans
#11
Jason M Cramer, Deborah Pohlmann, Fernando Gomez, Leslie Mark, Benjamin Kornegay, Chelsea Hall, Edhriz Siraliev-Perez, Ninad M Walavalkar, M Jeannette Sperlazza, Stephanie Bilinovich, Jeremy W Prokop, April L Hill, David C Williams
DNA cytosine methylation and methyl-cytosine binding domain (MBD) containing proteins are found throughout all vertebrate species studied to date. However, both the presence of DNA methylation and pattern of methylation varies among invertebrate species. Invertebrates generally have only a single MBD protein, MBD2/3, that does not always contain appropriate residues for selectively binding methylated DNA. Therefore, we sought to determine whether sponges, one of the most ancient extant metazoan lineages, possess an MBD2/3 capable of recognizing methylated DNA and recruiting the associated nucleosome remodeling and deacetylase (NuRD) complex...
January 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28092796/global-open-data-management-in-metabolomics
#12
REVIEW
Kenneth Haug, Reza M Salek, Christoph Steinbeck
Chemical Biology employs chemical synthesis, analytical chemistry and other tools to study biological systems. Recent advances in both molecular biology such as next generation sequencing (NGS) have led to unprecedented insights towards the evolution of organisms' biochemical repertoires. Because of the specific data sharing culture in Genomics, genomes from all kingdoms of life become readily available for further analysis by other researchers. While the genome expresses the potential of an organism to adapt to external influences, the Metabolome presents a molecular phenotype that allows us to asses the external influences under which an organism exists and develops in a dynamic way...
January 13, 2017: Current Opinion in Chemical Biology
https://www.readbyqxmd.com/read/28092755/coagulation-flocculation-sequential-with-fenton-or-photo-fenton-processes-as-an-alternative-for-the-industrial-textile-wastewater-treatment
#13
Edison GilPavas, Izabela Dobrosz-Gómez, Miguel Ángel Gómez-García
In this study, the industrial textile wastewater was treated using a chemical-based technique (coagulation-flocculation, C-F) sequential with an advanced oxidation process (AOP: Fenton or Photo-Fenton). During the C-F, Al2(SO4)3 was used as coagulant and its optimal dose was determined using the jar test. The following operational conditions of C-F, maximizing the organic matter removal, were determined: 700 mg/L of Al2(SO4)3 at pH = 9.96. Thus, the C-F allowed to remove 98% of turbidity, 48% of Chemical Oxygen Demand (COD), and let to increase in the BOD5/COD ratio from 0...
January 13, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28092135/self-supported-3d-pdcu-alloy-nanosheets-as-a-bifunctional-catalyst-for-electrochemical-reforming-of-ethanol
#14
Xiaojing Zhao, Lei Dai, Qing Qin, Fei Pei, Chengyi Hu, Nanfeng Zheng
3D PdCu alloy nanosheets exhibit enhanced electrocatalytic activity toward hydrogen evolution reaction and ethanol oxidation reaction in alkaline media. Simultaneous hydrogen and acetate production via a solar-powered cell for ethanol reforming has been fabricated using the nanosheets as bifunctional electrocatalysts. The device is promising for the production of both hydrogen and value-added chemicals using renewable energy.
January 16, 2017: Small
https://www.readbyqxmd.com/read/28092008/spatio-temporal-variation-of-septage-characteristics-of-a-semi-arid-metropolitan-city-in-a-developing-country
#15
D Krithika, Anu Rachel Thomas, Gomathy R Iyer, Martin Kranert, Ligy Philip
Septage is the solid sludge that accumulates in septic tanks over a period of time. Many of the developing countries in the world face the challenging task of septage management. Due to the high variability in the nature of septage, there is a need to study its physical and chemical characteristics in order to suggest a sustainable treatment methodology. The present study deals with the characterization of septage collected from different locations of Chennai city in India, in two different seasons (summer and winter)...
January 16, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28080055/morphological-transformation-of-surface-femtodroplets-upon-dissolution
#16
Shuhua Peng, Bat-El Pinchasik, Hao Hao, Helmuth Möhwald, Xuehua Zhang
Constructing controllable liquid patterns with high resolution and accuracy is of great importance in droplet depositions for a range of applications. Simple surface chemical micropatterns have been popularly used to regulate the shape of liquid droplets and the final structure of deposited materials. In this work, we study the morphological evolution of a dissolving femtoliter droplet pinned on multiple microdomains. On the basis of minimization of interfacial energy, the numerical simulations predict various symmetric droplet profiles in equilibrium at different liquid volumes...
January 17, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28078499/carbonaceous-chondrite-meteorites-the-chronicle-of-a-potential-evolutionary-path-between-stars-and-life
#17
Sandra Pizzarello, Everett Shock
The biogenic elements, H, C, N, O, P and S, have a long cosmic history, whose evolution can still be observed in diverse locales of the known universe, from interstellar clouds of gas and dust, to pre-stellar cores, nebulas, protoplanetary discs, planets and planetesimals. The best analytical window into this cosmochemical evolution as it neared Earth has been provided so far by the small bodies of the Solar System, some of which were not significantly altered by the high gravitational pressures and temperatures that accompanied the formation of larger planets and may carry a pristine record of early nebular chemistry...
January 11, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28078379/chitosan-sodium-tetradecyl-sulfate-hydrogel-characterization-and-preclinical-evaluation-of-a-novel-sclerosing-embolizing-agent-for-the-treatment-of-endoleaks
#18
Fatemeh Zehtabi, Vincent Dumont-Mackay, Ahmed Fatimi, Antony Bertrand-Grenier, Hélène Héon, Gilles Soulez, Sophie Lerouge
PURPOSE: To compare the efficacy of an embolization agent with sclerosing properties (made of chitosan and sodium tetradecyl sulfate, CH-STS) with a similar embolization agent but without sclerosing properties (made of chitosan, CH) in treating endoleaks in a canine endovascular aneurysm repair model. METHODS: Two chitosan-based radiopaque hydrogels were prepared, one with STS and one without STS. Their rheological, injectability, and embolizing properties were assessed in vitro; afterwards, their efficacy in occluding endoleaks was compared in a canine bilateral aneurysm model reproducing type I endoleaks (n = 9 each)...
January 11, 2017: Cardiovascular and Interventional Radiology
https://www.readbyqxmd.com/read/28075553/double-layer-graphene-outperforming-monolayer-as-catalyst-on-silicon-photocathode-for-hydrogen-production
#19
Uk Sim, Joonhee Moon, Joohee Lee, JungHyun An, Hyo-Yong Ahn, Dong Jin Kim, Insu Jo, Cheolho Jeon, Seungwu Han, Byung Hee Hong, Ki Tae Nam
Photoelectrochemical cells are used to split hydrogen and oxygen from water molecules to generate chemical fuels to satisfy our ever-increasing energy demands. However, it is a major challenge to design efficient catalysts to use in the photoelectochemical process. Recently, research has focused on carbon-based catalysts, as they are non-precious and environmentally benign. Interesting advances have also been made in controlling nanostructure interfaces and in introducing new materials as catalysts in the photoelectrochemical cell...
January 11, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28073449/harmful-algal-bloom-forecast-system-for-sw-ireland-part-ii-are-operational-oceanographic-models-useful-in-a-hab-warning-system
#20
Caroline Cusack, Tomasz Dabrowski, Kieran Lyons, Alan Berry, Guy Westbrook, Rafael Salas, Conor Duffy, Glenn Nolan, Joe Silke
This study investigated the application of a three-dimensional physical hydrodynamic model in a harmful algal bloom forecast system for Bantry Bay, southwest Ireland. Modelled oceanographic conditions were studied and used to help understand observed changes in the chemical and biological patterns from the national biotoxins and phytoplankton monitoring program. The study focused on two toxic events in 2013. An upwelling event was predicted by the model prior to the appearance and population increase of potentially toxic diatoms, Pseudo-nitzschia, and associated domoic acid in shellfish...
March 2016: Harmful Algae
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