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Chemical evolution

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https://www.readbyqxmd.com/read/28728030/enhanced-visible-light-photocatalytic-hydrogen-evolution-over-porphyrin-hybridized-graphitic-carbon-nitride
#1
Shunkang Mei, Jianping Gao, Ye Zhang, Jiangbing Yang, Yongli Wu, Xiaoxue Wang, Ruiru Zhao, Xiangang Zhai, Chaoyue Hao, Ruixia Li, Jing Yan
Tetra (4-carboxyphenyl) porphyrin (TCPP) was loaded on the surface of Pt/g-C3N4 via a simple adsorption process, and the microstructure and chemical structure of the composites were characterized by high resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV-visible diffused reflectance spectroscopy and photoluminescence spectroscopy. Loading TCPP onto Pt/g-C3N4 enhanced the visible-light-driven photocatalytic evolution of H2 from water...
July 10, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28727932/laboratory-studies-of-methane-and-its-relationship-to-prebiotic-chemistry
#2
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/28727757/development-of-organic-fertilizers-from-food-market-waste-and-urban-gardening-by-composting-in-ecuador
#3
J Jara-Samaniego, M D Pérez-Murcia, M A Bustamante, C Paredes, A Pérez-Espinosa, I Gavilanes-Terán, M López, F C Marhuenda-Egea, H Brito, R Moral
Currently, the management of urban waste streams in developing countries is not optimized yet, and in many cases these wastes are disposed untreated in open dumps. This fact causes serious environmental and health problems due to the presence of contaminants and pathogens. Frequently, the use of specific low-cost strategies reduces the total amount of wastes. These strategies are mainly associated to the identification, separate collection and composting of specific organic waste streams, such as vegetable and fruit refuses from food markets and urban gardening activities...
2017: PloS One
https://www.readbyqxmd.com/read/28726847/mapping-genome-wide-transcription-factor-binding-sites-using-dap-seq
#4
Anna Bartlett, Ronan C O'Malley, Shao-Shan Carol Huang, Mary Galli, Joseph R Nery, Andrea Gallavotti, Joseph R Ecker
To enable low-cost, high-throughput generation of cistrome and epicistrome maps for any organism, we developed DNA affinity purification sequencing (DAP-seq), a transcription factor (TF)-binding site (TFBS) discovery assay that couples affinity-purified TFs with next-generation sequencing of a genomic DNA library. The method is fast, inexpensive, and more easily scaled than chromatin immunoprecipitation sequencing (ChIP-seq). DNA libraries are constructed using native genomic DNA from any source of interest, preserving cell- and tissue-specific chemical modifications that are known to affect TF binding (such as DNA methylation) and providing increased specificity as compared with in silico predictions based on motifs from methods such as protein-binding microarrays (PBMs) and systematic evolution of ligands by exponential enrichment (SELEX)...
August 2017: Nature Protocols
https://www.readbyqxmd.com/read/28726380/assessment-of-the-stability-and-operability-of-cobalt-phosphide-electrocatalyst-for-hydrogen-evolution
#5
Hyun S Ahn, Allen J Bard
Transition metal phosphides have been investigated heavily as hydrogen evolution reaction (HER) catalysts. One of the most active transition metal phosphides, CoP, has been tested for its stability and operability under mild conditions that it may be exposed to in its applications (photoelectrochemistry and artificial photosynthesis). Surface-interrogation scanning electrochemical microscopy (SI-SECM) revealed that CoP HER catalyst is vulnerable to oxidation (by oxygen and chemical oxidants). The degradation mechanism was shown to be surface oxidation by dioxygen, followed by acid etching of the oxidized layer...
July 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28724931/assessing-the-shock-state-of-the-lunar-highlands-implications-for-the-petrogenesis-and-chronology-of-crustal-anorthosites
#6
J F Pernet-Fisher, K H Joy, D J P Martin, K L Donaldson Hanna
Our understanding of the formation and evolution of the primary lunar crust is based on geochemical systematics from the lunar ferroan anorthosite (FAN) suite. Recently, much effort has been made to understand this suite's petrologic history to constrain the timing of crystallisation and to interpret FAN chemical diversity. We investigate the shock histories of lunar anorthosites by combining Optical Microscope (OM) 'cold' cathodoluminescence (CL)-imaging and Fourier Transform Infrared (FTIR) spectroscopy analyses...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28723913/prebiotic-selection-for-motifs-in-a-model-of-template-free-elongation-of-polymers-within-compartments
#7
Grant Kinsler, Sam Sinai, Nicholas Keone Lee, Martin A Nowak
The transition from prelife where self-replication does not occur, to life which exhibits self-replication and evolution, has been a subject of interest for many decades. Membranes, forming compartments, seem to be a critical component of this transition as they provide several concurrent benefits. They maintain localized interactions, generate electro-chemical gradients, and help in selecting cooperative functions as they arise. These functions pave the way for the emergence and maintenance of simple metabolic cycles and polymers...
2017: PloS One
https://www.readbyqxmd.com/read/28723577/enabling-tools-for-high-throughput-detection-of-metabolites-metabolic-engineering-and-directed-evolution-applications
#8
REVIEW
Jyun-Liang Lin, James M Wagner, Hal S Alper
Within the Design-Build-Test Cycle for strain engineering, rapid product detection and selection strategies remain challenging and limit overall throughput. Here we summarize a wide variety of modalities that transduce chemical concentrations into easily measured absorbance, luminescence, and fluorescence signals. Specifically, we cover protein-based biosensors (including transcription factors), nucleic acid-based biosensors, coupled enzyme reactions, bioorthogonal chemistry, and fluorescent and chromogenic dyes and substrates as modalities for detection...
July 16, 2017: Biotechnology Advances
https://www.readbyqxmd.com/read/28722730/tunable-in-plane-torsional-strength-of-surface-functionalized-two-dimensional-nanomaterials
#9
Qianling Lin, Yinfeng Li, Haimin Yao
In this paper, the in-plane torsional properties of two dimensional nanomaterials are revealed to be tunable by surface functionalization using molecular dynamics simulations. The torsional strengths of both graphene and graphyne under circular shearing are found to first decrease and then increase anomalously with the increase of the hydrogenation ratio. The minimum strength of such U-shaped strength evolution appears at different hydrogenation ratios H for graphene (H = 50%) and graphyne (H = 70%), demonstrating a correlation between hydrogenation and the unit lattices of 2D nanomaterials...
July 19, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28722179/direct-synthesis-of-large-area-2d-mo2-c-on-in-situ-grown-graphene
#10
Dechao Geng, Xiaoxu Zhao, Zhongxin Chen, Weiwei Sun, Wei Fu, Jianyi Chen, Wei Liu, Wu Zhou, Kian Ping Loh
As a new member of the MXene group, 2D Mo2 C has attracted considerable interest due to its potential application as electrodes for energy storage and catalysis. The large-area synthesis of Mo2 C film is needed for such applications. Here, the one-step direct synthesis of 2D Mo2 C-on-graphene film by molten copper-catalyzed chemical vapor deposition (CVD) is reported. High-quality and uniform Mo2 C film in the centimeter range can be grown on graphene using a Mo-Cu alloy catalyst. Within the vertical heterostructure, graphene acts as a diffusion barrier to the phase-segregated Mo and allows nanometer-thin Mo2 C to be grown...
July 19, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28719578/de-novo-active-sites-for-resurrected-precambrian-enzymes
#11
Valeria A Risso, Sergio Martinez-Rodriguez, Adela M Candel, Dennis M Krüger, David Pantoja-Uceda, Mariano Ortega-Muñoz, Francisco Santoyo-Gonzalez, Eric A Gaucher, Shina C L Kamerlin, Marta Bruix, Jose A Gavira, Jose M Sanchez-Ruiz
Protein engineering studies often suggest the emergence of completely new enzyme functionalities to be highly improbable. However, enzymes likely catalysed many different reactions already in the last universal common ancestor. Mechanisms for the emergence of completely new active sites must therefore either plausibly exist or at least have existed at the primordial protein stage. Here, we use resurrected Precambrian proteins as scaffolds for protein engineering and demonstrate that a new active site can be generated through a single hydrophobic-to-ionizable amino acid replacement that generates a partially buried group with perturbed physico-chemical properties...
July 18, 2017: Nature Communications
https://www.readbyqxmd.com/read/28719188/phage-selection-of-cyclic-peptides-for-application-in-research-and-drug-development
#12
Kaycie Deyle, Xu-Dong Kong, Christian Heinis
Cyclic peptides can bind to protein targets with high affinities and selectivities, which makes them an attractive modality for the development of research reagents and therapeutics. Additional properties, including low inherent toxicity, efficient chemical synthesis, and facile modification with labels or immobilization reagents, increase their attractiveness. Cyclic peptide ligands against a wide range of protein targets have been isolated from natural sources such as bacteria, fungi, plants, and animals...
July 18, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28718696/tumor-induced-disorder-of-iron-metabolism-in-major-organs-a-new-insight-from-chemical-speciation-of-iron
#13
Rujie Chen, Guangcun Chen
Objective To investigate the evolution of iron speciation in major organs of tumor-bearing mice and its role in cancer formation and cancer-associated complications. Methods The concentration and chemical speciation of iron in the spleen, liver, lung, kidney, heart, blood, muscle, and tumor tissue of healthy mice and tumor-bearing mice were studied by synchrotron radiation-based total reflection X-ray fluorescence spectrometry (SR-TXRF) coupled with X-ray absorption spectroscopy (XAS). Results The TXRF and XAS results showed that the iron content, especially the ferritin content, significantly decreased in the blood and spleen but significantly increased in the liver, lung, and muscle of mice after tumor implantation...
January 1, 2017: Journal of International Medical Research
https://www.readbyqxmd.com/read/28716358/the-ability-of-lizards-to-identify-an-artificial-batesian-mimic
#14
Josef Beneš, Petr Veselý
Birds are usually considered the main predators shaping the evolution of aposematic signals and mimicry. Nevertheless, some lizards also represent predominately visually oriented predators, so they may also play an important role in the evolution of aposematism. Despite this fact, experimental evidence regarding the responses of lizards to aposematic prey is very poor compared to such evidence in birds. Lizards possess very similar sensory and cognitive abilities to those of birds and their response to aposematic prey may thus be affected by very similar processes...
June 3, 2017: Zoology: Analysis of Complex Systems, ZACS
https://www.readbyqxmd.com/read/28715205/polymerase-chain-transcription-exponential-synthesis-of-rna-and-modified-rna
#15
Tingjian Chen, Floyd E Romesberg
There is increasing demand for RNA and modified RNA oligonucleotides, but in contrast to DNA oligonucleotides, they are typically prohibitively expensive to chemically synthesize, and unlike longer RNAs, they are only inefficiently produced by in vitro transcription, especially when modified. To address these challenges, we previously reported the evolution of a thermostable DNA polymerase, SFM4-3, that more efficiently accepts substrates with 2'-substituents. We now show that SFM4-3 efficiently transcribes RNA or 2'-F-modified RNA and that it also efficiently PCR amplifies oligonucleotides of mixed RNA and DNA composition...
July 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28712825/use-of-biomarkers-to-evaluate-the-effects-of-environmental-stressors-on-mytilus-galloprovincialis-sampled-along-the-moroccan-coasts-integrating-biological-and-chemical-data
#16
Bouchra El Haimeur, Mina Bouhallaoui, Mariama Zbiry, Najat Elkhiati, Sophia Talba, Susanna Sforzini, Aldo Viarengo, Ali Benhra
A biomonitoring study using wild Mytilus galloprovincialis mussels sampled from six sites along the Moroccan coasts evaluated whether select biomarkers are suitable for identifying and quantifying pollution-induced stress syndrome in mussels. Lysosomal membrane stability was confirmed to be a highly sensitive biological parameter, and acetylcholinesterase activity was found a suitable biomarker of neurotoxicity. Metallothionein concentrations were in line with heavy metal concentrations detected in mussel tissues...
June 13, 2017: Marine Environmental Research
https://www.readbyqxmd.com/read/28711007/carbon-dynamics-in-a-late-quaternary-age-coastal-limestone-aquifer-system-undergoing-saltwater-intrusion
#17
Eliza Bryan, Karina T Meredith, Andy Baker, Martin S Andersen, Vincent E A Post
This study investigates the inorganic and organic aspects of the carbon cycle in groundwaters throughout the freshwater lens and transition zone of a carbonate island aquifer and identifies the transformation of carbon throughout the system. We determined (14)C and (13)C carbon isotope values for both DIC and DOC in groundwaters, and investigated the composition of DOC throughout the aquifer. In combination with hydrochemical and (3)H measurements, the chemical evolution of groundwaters was then traced from the unsaturated zone to the deeper saline zone...
July 12, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28710859/carbonitride-aerogels-for-the-photoredox-conversion-of-water
#18
Honghui Ou, Pengju Yang, Lihua Lin, Masakazu Anpo, Xinchen Wang
Aerogel structures have attracted increasing research interest in energy storage and conversion owing to their unique structural features, and a variety of matters has been engineered into aerogels, including carbons, metal oxides, linear polymers and even metal chalcogenides. However, manufacturing of aerogels from nitride-based materials, particularly the emerging light-weight carbonitride (CN) is rarely reported. Here, we develop a facile method based on self-assembly chemistry to produce self-supported CN aerogels, without using any cross-linking agents...
July 15, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28708383/unlocking-reactivity-of-trpb-a-general-biocatalytic-platform-for-synthesis-of-tryptophan-analogs
#19
David K Romney, Javier Murciano-Calles, Jöri Elias Wehrmüller, Frances H Arnold
Derivatives of the amino acid tryptophan (Trp) serve as precursors for the chemical and biological synthesis of complex molecules with a wide range of biological properties. Trp analogs are also valuable as building blocks for medicinal chemistry and as tools for chemical biology. While the enantioselective synthesis of Trp analogs is often lengthy and requires the use of protecting groups, enzymes have the potential to synthesize such products in fewer steps and with the pristine chemo- and stereoselectivity that is a hallmark of biocatalysis...
July 14, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28706289/hydrogen-self-diffusion-in-single-crystal-olivine-and-electrical-conductivity-of-the-earth-s-mantle
#20
Davide Novella, Benjamin Jacobsen, Peter K Weber, James A Tyburczy, Frederick J Ryerson, Wyatt L Du Frane
Nominally anhydrous minerals formed deep in the mantle and transported to the Earth's surface contain tens to hundreds of ppm wt H2O, providing evidence for the presence of dissolved water in the Earth's interior. Even at these low concentrations, H2O greatly affects the physico-chemical properties of mantle materials, governing planetary dynamics and evolution. The diffusion of hydrogen (H) controls the transport of H2O in the Earth's upper mantle, but is not fully understood for olivine ((Mg, Fe)2SiO4) the most abundant mineral in this region...
July 13, 2017: Scientific Reports
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