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Frontiers in Chemistry

Yongqi Tian, Xiuping Lin, Xuefeng Zhou, Yonghong Liu
Seven new phenol derivatives named coleophomones E and F ( 1 , 2 ), diorcinols L and M ( 3 , 4 ), 1-hydroxy-6-methyl-11-methoxy-8-hydroxymethylxanthone ( 5 ), porric acid E ( 6 ), and 7-(2-hydroxyphenyl) butane-7,8,9-triol ( 7 ), were isolated from the EtOAc extract of the marine sponge-derived fungus Didymellaceae sp. SCSIO F46, together with 10 known compounds. Their structures were determined by spectroscopic analyses, including NMR, MS, X-ray diffraction, and theoretical calculations. Each of 1 and 2 contains an unusual spiro [cyclohexane-1,2'-inden] moiety, which is relatively seldom in nature products...
2018: Frontiers in Chemistry
Anamika Sharma, Ayman El-Faham, Beatriz G de la Torre, Fernando Albericio
The study involves exploring the three orthogonal sites for aromatic nucleophilic substitution in cyanuric chloride (TCT). The preferential order of incorporation of different nucleophiles (such as alcohol, thiol, and amine) was addressed both experimentally and theoretically. The preferential order for incorporating nucleophiles in TCT was found to be alcohol > thiol > amine.
2018: Frontiers in Chemistry
Ziming Yang, Hong-Hui Wu, Zhiming Zheng, Yong Cheng, Pei Li, Qiaobao Zhang, Ming-Sheng Wang
One of the crucial challenges for applying Sn as an anode of lithium-ion batteries (LIBs) is the dramatic volume change during lithiation/delithiation process, which causes a rapid capacity fading and then deteriorated battery performance. To address this issue, herein, we report the design and fabrication of Sn encapsulated carbon nanoboxes (denoted as Sn@C) with yolk@shell architectures. In this design, the carbon shell can facilitate the good transport kinetics whereas the hollow space between Sn and carbon shell can accommodate the volume variation during repeated charge/discharge process...
2018: Frontiers in Chemistry
Huan Chang, Yiyi Zhang, Fan Yang, Changtao Wang, Haifeng Dong
Circulating tumor DNA (ctDNA), originating directly from the tumor or circulating tumor cells, may reflect the entire tumor genom and has gained considerable attention for its potential clinical diagnosis and prognosis throughout the treatment regimen. However, the reliable and robust ctDNA detection remains a key challenge. Here, this work designs a pair of DNA clutch separation probes and an ideal discrimination probes based on toehold-mediated strand displacement reaction (TSDR) to specifically recognize ctDNA...
2018: Frontiers in Chemistry
Cher Pin Song, Poh En Liew, Zora Teh, Schian Pei Lim, Pau Loke Show, Chien Wei Ooi
The formation of aqueous two-phase system (ATPS) with the environmentally friendly and recyclable ionic liquid has been gaining popularity in the field of protein separation. In this study, the ATPSs comprising N , N -dimethylammonium N ' ,N '-dimethylcarbamate (DIMCARB) and thermo-responsive poly(propylene) glycol (PPG) were applied for the recovery of recombinant green fluorescent protein (GFP) derived from Escherichia coli . The partition behavior of GFP in the PPG + DIMCARB + water system was investigated systematically by varying the molecular weight of PPG and the total composition of ATPS...
2018: Frontiers in Chemistry
Mauro Coduri, Stefano Checchia, Mariangela Longhi, Davide Ceresoli, Marco Scavini
The need for high efficiency energy production, conversion, storage and transport is serving as a robust guide for the development of new materials. Materials with physical-chemical properties matching specific functions in devices are produced by suitably tuning the crystallographic- defect- and micro-structure of the involved phases. In this review, we discuss the case of Rare Earth doped Ceria. Due to their high oxygen diffusion coefficient at temperatures higher than ~500°C, they are very promising materials for several applications such as electrolytes for Solid Oxide Fuel and Electrolytic Cells (SOFC and SOEC, respectively)...
2018: Frontiers in Chemistry
Alessandra Zanoletti, Fabjola Bilo, Laura Borgese, Laura E Depero, Ario Fahimi, Jessica Ponti, Andrea Valsesia, Rita La Spina, Tiziano Montini, Elza Bontempi
The World Health Organization reports that every year several million people die prematurely due to air pollution. Poor air quality is a by-product of unsustainable policies in transportation, energy, industry, and waste management in the world's most crowded cities. Particulate matter (PM) is one of the major element of polluted air. PM can be composed by organic and inorganic species. In particular, heavy metals present in PM include, lead (Pb), mercury (Hg), cadmium, (Cd), zinc (Zn), nickel (Ni), arsenic (As), and molybdenum (Mo)...
2018: Frontiers in Chemistry
Chunshuai Huang, Chunfang Yang, Yiguang Zhu, Wenjun Zhang, Chengshan Yuan, Changsheng Zhang
The structure diversity of type II polyketide synthases-derived bacterial aromatic polyketides is often enhanced by enzyme controlled or spontaneous cyclizations. Here we report the discovery of bacterial aromatic polyketides generated from 5 different cyclization modes and pathway crosstalk between the host and the heterologous fluostatin biosynthetic gene cluster derived from a marine bacterium. The discovery of new compound SEK43F ( 2 ) represents an unusual carbon skeleton resulting from a pathway crosstalk, in which a pyrrole-like moiety derived from the host Streptomyces albus J1074 is fused to an aromatic polyketide SEK43 generated from the heterologous fluostatin type II PKSs...
2018: Frontiers in Chemistry
Elena Lenci, Riccardo Innocenti, Gloria Menchi, Andrea Trabocchi
Diversity-Oriented Synthesis (DOS) consists of generating structurally diverse compounds from a complexity-generating reaction followed by cyclization steps and appendage diversity. DOS has gathered interest to systematically explore the chemical space by generating high-quality small-molecule collections as probes to investigate biological pathways. The generation of heterocycles using amino acid and sugar derivatives as building blocks is a powerful approach to access chemical and geometrical diversity thanks to the high number of stereocenters and the polyfunctionality of such compounds...
2018: Frontiers in Chemistry
Yingzhang Yan, Jinzhen Huang, Xianjie Wang, Tangling Gao, Yumin Zhang, Tai Yao, Bo Song
Electrochemical water splitting in alkaline media plays an important role in mass production of hydrogen. Ruthenium (Ru), as the cheapest member of platinum-group metals, has attracted much attention, and the incorporation of trace amount of Ru with cobalt phosphide could significantly improve the hydrogen evolution reaction (HER) catalytic activity. In this work, ruthenium-incorporated cobalt phosphide nanocubes are synthesized via a reaction between Co-Co Prussian blue analog (Co-PBA) and ruthenium chloride (RuCl3 ) followed by the phosphidation...
2018: Frontiers in Chemistry
Jacobo Gómez-González, Diego G Peña, Ghofrane Barka, Giuseppe Sciortino, Jean-Didier Maréchal, Miguel Vázquez López, M Eugenio Vázquez
We propose that peptides are highly versatile platforms for the precise design of supramolecular metal architectures, and particularly, for the controlled assembly of helicates. In this context, we show that the bacteriophage T4 Fibritin foldon (T4Ff) can been engineered on its N-terminus with metal-chelating 2,2'-bipyridine units that stereoselectively assemble in the presence of Fe(II) into parallel, three-stranded peptide helicates with preferred helical orientation. Modeling studies support the proposed self-assembly and the stability of the final helicate...
2018: Frontiers in Chemistry
Amy Timmins, Nicholas J Fowler, Jim Warwicker, Grit D Straganz, Sam P de Visser
In this work we present the first computational study on the hectochlorin biosynthesis enzyme HctB, which is a unique three-domain halogenase that activates non-amino acid moieties tethered to an acyl-carrier, and as such may have biotechnological relevance beyond other halogenases. We use a combination of small cluster models and full enzyme structures calculated with quantum mechanics/molecular mechanics methods. Our work reveals that the reaction is initiated with a rate-determining hydrogen atom abstraction from substrate by an iron (IV)-oxo species, which creates an iron (III)-hydroxo intermediate...
2018: Frontiers in Chemistry
Sereyvath Yoeun, Kyoungwon Cho, Oksoo Han
Allene oxide cyclase (AOC) is a key enzyme in the jasmonic acid (JA) biosynthetic pathway in plants, during which it catalyzes stereospecific conversion of 12,13( S )-epoxy-9( Z ),11,15( Z )-octadecatrienoic acid (12,13-EOT) to cis (+)-12-oxophytodienoic acid. Here, rice allene oxide cyclase (OsAOC) was localized to the chloroplast and its native oligomeric structure was analyzed by gel electrophoresis in the absence and presence of a protein-crosslinking reagent. The results suggest that OsAOC exists in solution as a mixture of monomers, dimers, and higher order multimers...
2018: Frontiers in Chemistry
Klaus-J Appenroth, K Sowjanya Sree, Manuela Bog, Josef Ecker, Claudine Seeliger, Volker Böhm, Stefan Lorkowski, Katrin Sommer, Walter Vetter, Karla Tolzin-Banasch, Rita Kirmse, Matthias Leiterer, Christine Dawczynski, Gerhard Liebisch, Gerhard Jahreis
Species of the genus Wolffia are traditionally used as human food in some of the Asian countries. Therefore, all 11 species of this genus, identified by molecular barcoding, were investigated for ingredients relevant to human nutrition. The total protein content varied between 20 and 30% of the freeze-dry weight, the starch content between 10 and 20%, the fat content between 1 and 5%, and the fiber content was ~25%. The essential amino acid content was higher or close to the requirements of preschool-aged children according to standards of the World Health Organization...
2018: Frontiers in Chemistry
Zengren Tao, Zhiyun Yang, Yafang Guo, Yaping Zeng, Jianrong Xiao
Due to the high theoretical specific capacity of lithium-sulfur batteries, it is considered the most promising electrochemical energy storage device for the next generation. However, the development of lithium-sulfur battery has been restricted by its low cycle efficiency and low capacity. We present a Plane double-layer structure of AC@S cathode to improve the electrochemical performance of lithium-sulfur batteries. The battery with this cathode showed good electrochemical performance. The initial discharge capacity of the battery with the structure of AC@S cathode could reach 1,166 mAhg-1 at 0...
2018: Frontiers in Chemistry
Shijie Li, Wei Jiang, Kaibing Xu, Shiwei Hu, Yu Liu, Yingtang Zhou, Jianshe Liu
In this study, flower-like AgI/BiOCOOH heterojunctions were constructed through a two-step procedure involving the solvothermal synthesis of BiOCOOH microflowers followed by AgI modification using a precipitation method. These novel photocatalysts were systematically examined by XRD, UV-vis DRS, SEM, TEM, EDS, and PL spectroscopy techniques. The AgI/BiOCOOH heterojunction were studied as a decent photocatalyst for the removal of the industrial dye (rhodamine B, and methyl blue) and antibiotic (tetracycline) under visible light...
2018: Frontiers in Chemistry
Erdal Dinç, Zehra Yazan
In research and development laboratories, chemical or pharmaceutical analysis has been carried out by evaluating sample signals obtained from instruments. However, the qualitative and quantitative determination based on raw signals may not be always possible due to sample complexity. In such cases, there is a need for powerful signal processing methodologies that can effectively process raw signals to get correct results. Wavelet transform is one of the most indispensable and popular signal processing methods currently used for noise removal, background correction, differentiation, data smoothing and filtering, data compression and separation of overlapping signals etc...
2018: Frontiers in Chemistry
Wei Xiao, Zhiyan Wang, Chang Miao, Ping Mei, Yan Zhang, Xuemin Yan, Minglei Tian, Yu Jiang, Jingjing Liu
The spherical-like and honeycomb structural Li0.1 Ca0.9 TiO3 particles are prepared by spray drying combined with following calcination confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray spectrometer (EDS). The poly (vinylidene fluoride- co -hexafluoropropylene) (P(VDF-HFP))-based composite polymer electrolytes (CPEs) modified with the particles are fabricated by phase inversion and activation processes. The characterization results show that the as-prepared CPE membranes possess the smoothest surface and most abundant micropores with the lowest crystallinity with adding the particles into the polymer matrix, which results in high ionic conductivity (3...
2018: Frontiers in Chemistry
Hui Chen, Yan Liu, Feng Lu, Yongbing Cao, Zhi-Min Zhang
Obtaining consistent spectra by using different spectrometers is of critical importance to the fields that rely heavily on Raman spectroscopy. The quality of both qualitative and quantitative analysis depends on the stability of specific Raman peak shifts across instruments. Non-linear drifts in the Raman shifts can, however, introduce additional complexity in model building, potentially even rendering a model impractical. Fortunately, various types of shift correction methods can be applied in data preprocessing in order to address this problem...
2018: Frontiers in Chemistry
Michele Galizia, Kelly P Bye
The vast majority of industrial chemical synthesis occurs in organic solution. Solute concentration and solvent recovery consume ~50% of the energy required to produce chemicals and pose problems that are as relevant as the synthesis process itself. Separation and purification processes often involve a phase change and, as such, they are highly energy-intensive. However, novel, energy-efficient technologies based on polymer membranes are emerging as a viable alternative to thermal processes. Despite organic solvent nanofiltration (OSN) could revolutionize the chemical, petrochemical, food and pharmaceutical industry, its development is still in its infancy for two reasons: (i) the lack of fundamental knowledge of elemental transport phenomena in OSN membranes, and (ii) the instability of traditional polymer materials in chemically challenging environments...
2018: Frontiers in Chemistry
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