1,393,312 results match your criteria Chemical communications Cambridge England[Journal]


A composite of Fe3O4@C and multilevel-porous carbon as high-rate and long-life anode materials for lithium-ion batteries.

Nanotechnology 2019 Apr 17. Epub 2019 Apr 17.

State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, College of Chemistry & Chemical Engineering, Changsha 410082, P R CHINA, Changsha, CHINA.

The iron oxides-based anode materials are widely studied and reported due to their abundance, low cost, high energy density and environmental friendliness for lithium ion batteries (LIBs). However, the application of LIBs is always limited by the poor rate capability and stability. In order to tackle these issues, a novel material with carbon-encapsulated Fe3O4 nanorods stuck together by multilevel porous carbon (Fe3O4@C/PC) is prepared through directly carbonizing the Fe-based metal-organic framework under nitrogen atmosphere. Read More

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http://dx.doi.org/10.1088/1361-6528/ab1a83DOI Listing

Levels, spatial distribution and isomer profiles of perfluoroalkyl acids in soil, groundwater and tap water around a manufactory in China.

Chemosphere 2019 Apr 9;227:305-314. Epub 2019 Apr 9.

Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, China.

In this study, 32 surface soil samples, 24 groundwater samples, and 6 tap water samples were collected around a perfluorosulfonates (PFSAs) manufactory in China to analyze the distributions of perfluoroalkyl acids (PFAAs) including linear and branched isomers. The total concentrations of PFAAs (∑PFAAs) ranged from 1.30 to 913 ng/g on a dry weight basis (dw), 31. Read More

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http://dx.doi.org/10.1016/j.chemosphere.2019.04.027DOI Listing

Quantitation of vitamin K1 in serum using online SPE-LC-MS/MS and the challenges of working with vitamin K.

J Chromatogr B Analyt Technol Biomed Life Sci 2019 Apr 7;1117:41-48. Epub 2019 Apr 7.

Department of Clinical Biochemistry and Immunology, Lillebaelt Hospital, Vejle, Denmark.

Vitamin K1 (phylloquinone) is one of the vitamin Ks. Several studies have previously investigated the role of vitamin K1 status in respect to disease, but without consistent results. Since vitamin K deficiency has been associated with different disease states it is important to develop a biochemical analysis with sufficient sensitivity and a low limit of quantitation (LOQ). Read More

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https://linkinghub.elsevier.com/retrieve/pii/S15700232183176
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http://dx.doi.org/10.1016/j.jchromb.2019.04.010DOI Listing
April 2019
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Effect of oxidation-induced aging on the adsorption and co-adsorption of tetracycline and Cu onto biochar.

Sci Total Environ 2019 Apr 8;673:522-532. Epub 2019 Apr 8.

Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang 310058, China.

The bamboo biochars pyrolyzed at 400 °C and 600 °C (BC400 and BC600) were modified by hydrogen peroxide (HO) to obtain the oxidized biochars. Biochar stability and the effect of oxidation treatment on the adsorption and co-adsorption of tetracycline (TC) and Cu onto biochars were investigated. The calculated carbon loss of biochars after oxidation treatment indicated that BC600 presented higher carbon stability than BC400 due to the condensed aromatic structure of biochar. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S00489697193160
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http://dx.doi.org/10.1016/j.scitotenv.2019.04.089DOI Listing
April 2019
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Soil organic carbon stabilization mechanisms in a subtropical mangrove and salt marsh ecosystems.

Sci Total Environ 2019 Apr 10;673:502-510. Epub 2019 Apr 10.

Collaborative Innovation Center of Sustainable Forestry in Southern China of Jiangsu Province, Nanjing Forestry University, Nanjing 210037, China.

Mangrove and salt marsh ecosystems are one of the most productive ecosystems in terrestrial ecosystems, playing an important role in global carbon (C) cycling. The anaerobic condition in coastal wetland usually impedes the decomposition of soil organic carbon (SOC). However, the intrinsic stabilization mechanisms of SOC other than environmental factors are poorly understood in coastal wetland. Read More

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http://dx.doi.org/10.1016/j.scitotenv.2019.04.122DOI Listing

Recognition of silver cations by multifarene[2,2] chemosensors with unexpected fluorescence response.

Spectrochim Acta A Mol Biomol Spectrosc 2019 Apr 9;218:213-220. Epub 2019 Apr 9.

Institute of Biomedical & Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Avenue, Shenzhen 518055, China. Electronic address:

Fluorescent chemosensors based on a new macrocyclic compound, multifarene[2,2], with modification by triazole-linked pyrene or anthracene were synthesized. These macrocyclic sensors exhibited high affinity and selectivity toward Ag over other metal ions, with ratiometric or enhanced response of their fluorescence emissions depending upon the substituent species for coordination to Ag, and an unexpected response to a concentration threshold of the metal cations was discovered. The experimental evidences of fluorescence spectra, H NMR titration, IR spectra, and high-resolution mass spectra suggested the coordination behaviors of the sensors with Ag, that is, the 1:1 complexes were formed with moderate association constants of about 10 L·mol, and the sulfur atoms on macrocyclic ligand should affinite to the metal cations. Read More

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http://dx.doi.org/10.1016/j.saa.2019.04.011DOI Listing

Perylenequinone-based "turn on" fluorescent probe for hydrogen sulfide with high sensitivity in living cells.

Spectrochim Acta A Mol Biomol Spectrosc 2019 Mar 29;218:206-212. Epub 2019 Mar 29.

Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China. Electronic address:

Hydrogen sulfide (HS) is a kind of gaseous signal molecule in many physiological processes. In order to detect HS, a novel "turn on" fluorescent probe 6,12-dihydroxyperylene-1,7-dione (DPD) was designed and synthesized. The probe DPD is fluorescence silence, while the addition of HS induces an obvious green fluorescence with an obvious color change from dark blue to yellow-green. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S13861425193036
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http://dx.doi.org/10.1016/j.saa.2019.03.112DOI Listing
March 2019
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Recyclable fluorescent chemodosimeters based on 8-hydroxyquinoline derivatives for highly sensitive and selective detection of mercury(II) in aqueous media and test strips.

Spectrochim Acta A Mol Biomol Spectrosc 2019 Apr 4;218:196-205. Epub 2019 Apr 4.

School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China. Electronic address:

Four novel highly selective 8-hydroxyquinoline-based fluorescent chemodosimeters (1-4) were synthesized for the rapid analysis of Hg in aqueous solution and on paper strips, which probably attributed to the excited state intramolecular proton transfer (ESIPT) process. Chemodosimeter 1 was evaluated as a Hg-ratiometric fluorescent sensor while others (2, 3 and 4) displayed fluorescence turn-on response for Hg among the various survey metal ions. We demonstrated that chemodosimeters (1-4) could recognized Hg ions based on a 1:1 stoichiometric binding event with fast detection time. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S13861425193037
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http://dx.doi.org/10.1016/j.saa.2019.04.004DOI Listing
April 2019
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Comparative analysis of pyrimidine substituted aminoacyl-sulfamoyl nucleosides as potential inhibitors targeting class I aminoacyl-tRNA synthetases.

Eur J Med Chem 2019 Apr 5;173:154-166. Epub 2019 Apr 5.

Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49 Box 1041, B-3000, Leuven, Belgium. Electronic address:

Aminoacyl-tRNA synthetases (aaRSs) catalyse the ATP-dependent coupling of an amino acid to its cognate tRNA. Being vital for protein translation aaRSs are considered a promising target for the development of novel antimicrobial agents. 5'-O-(N-aminoacyl)-sulfamoyl adenosine (aaSA) is a non-hydrolysable analogue of the aaRS reaction intermediate that has been shown to be a potent inhibitor of this enzyme family but is prone to chemical instability and enzymatic modification. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S02235234193030
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http://dx.doi.org/10.1016/j.ejmech.2019.04.003DOI Listing
April 2019
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Synthetic approaches and pharmaceutical applications of chloro-containing molecules for drug discovery: A critical review.

Eur J Med Chem 2019 Apr 10;173:117-153. Epub 2019 Apr 10.

School of Chemistry, Chemical Engineering and Life Science, School of Materials Science and Engineering, Wuhan University of Technology, 205 Luoshi Road, Wuhan, 430070, PR China. Electronic address:

At present more than 250 FDA approved chlorine containing drugs were available in the market and many pharmaceutically important drug candidates in pre-clinical trials. Thus, it is quite obvious to expect that in coming decades there will be an even greater number of new chlorine-containing pharmaceuticals in market. Chlorinated compounds represent the family of compounds promising for use in medicinal chemistry. Read More

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http://dx.doi.org/10.1016/j.ejmech.2019.03.063DOI Listing

Four new guaiane sesquiterpenoids from agarwood of Aquilaria filaria.

Fitoterapia 2019 Apr 14. Epub 2019 Apr 14.

Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, PR China. Electronic address:

Six 8,12-epoxyguaiane sesquiterpenes (1-6), together with two known 2-(2-phenylethyl)chromone derivatives (7-8) were isolated from agarwood originating from Aquilaria filaria. Their structures were established by spectroscopic methods including IR, HRESIMS, 1D, and 2D NMR, and comparison with the published data. The absolute configuration of compound 1 was unambiguously determined by quantum chemical calculation of the electronic circular dichroism (ECD) spectrum. Read More

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http://dx.doi.org/10.1016/j.fitote.2019.04.007DOI Listing

Schekwanglupaside C, a new lupane saponin from Schefflera kwangsiensis, is a potent activator of sarcoplasmic reticulum Ca-ATPase.

Fitoterapia 2019 Apr 14. Epub 2019 Apr 14.

State Key Laboratory of Natural Medicines and Department of Pharmacology, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, PR China. Electronic address:

Schefflera kwangsiensis Merr. ex H.L. Read More

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http://dx.doi.org/10.1016/j.fitote.2019.04.005DOI Listing

Improved Lovastatin Production by Inhibiting (+)-Geodin Biosynthesis in Aspergillus terreus.

N Biotechnol 2019 Apr 14. Epub 2019 Apr 14.

The University of Sydney, School of Chemical and Biomolecular Engineering, Australia.

Lovastatin is widely prescribed to reduce elevated levels of cholesterol and prevent heart-related diseases. Cultivation of Aspergillus terreus (ATCC 20542) with carbohydrates or low-value feedstocks such as glycerol produces lovastatin as a secondary metabolite and (+)-geodin as a by-product. An A. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S18716784183167
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http://dx.doi.org/10.1016/j.nbt.2019.04.003DOI Listing
April 2019
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Poisoning associated with the use of mushrooms: A review of the global pattern and main characteristics.

Food Chem Toxicol 2019 Apr 14. Epub 2019 Apr 14.

Laboratory of Toxicology, University of Crete, Voutes, Heraklion, Crete, 71003, Greece.

Worldwide, special attention has been paid to wild mushrooms-induced poisoning. This review article provides a report on the global pattern and characteristics of mushroom poisoning and identifies the magnitude of mortality induced by mushroom poisoning. In this work, reasons underlying mushrooms-induced poisoning, and contamination of edible mushrooms by heavy metals and radionuclides, are provided. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S02786915193021
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http://dx.doi.org/10.1016/j.fct.2019.04.016DOI Listing
April 2019
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Horizontal Boundary Cells, a Special Group of Somitic Cells, Play Crucial Roles in the Formation of Dorsoventral Compartments in Teleost Somite.

Cell Rep 2019 Apr;27(3):928-939.e4

Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. Electronic address:

Establishment of robust gene expression boundary is crucial for creating elaborate morphology during development. However, mechanisms underlying boundary formation have been extensively studied only in a few model systems. We examined the establishment of zic1/zic4-expression boundary demarcating dorsoventral boundary of the entire trunk of medaka fish (Oryzias latipes) and identified a subgroup of dermomyotomal cells called horizontal boundary cells (HBCs) as crucial players for the boundary formation. Read More

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http://dx.doi.org/10.1016/j.celrep.2019.03.068DOI Listing

Quantitative Characterization of α-Synuclein Aggregation in Living Cells through Automated Microfluidics Feedback Control.

Cell Rep 2019 Apr;27(3):916-927.e5

Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy; Department of Chemical, Materials and Industrial Production Engineering, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy. Electronic address:

Aggregation of α-synuclein and formation of inclusions are hallmarks of Parkinson's disease (PD). Aggregate formation is affected by cellular environment, but it has been studied almost exclusively in cell-free systems. We quantitatively analyzed α-synuclein inclusion formation and clearance in a yeast cell model of PD expressing either wild-type (WT) α-synuclein or the disease-associated A53T mutant from the galactose (Gal)-inducible promoter. Read More

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http://dx.doi.org/10.1016/j.celrep.2019.03.081DOI Listing

Phages Mediate Bacterial Self-Recognition.

Cell Rep 2019 Apr;27(3):737-749.e4

Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802-4400, USA. Electronic address:

Cells are social, and self-recognition is a conserved aspect of group behavior where cells assist kin and antagonize non-kin. However, the role of phage in self-recognition is unexplored. Here we find that a demarcation line is formed between different swimming Escherichia coli strains but not between identical clones; hence, motile cells discriminate between self and non-self. Read More

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http://dx.doi.org/10.1016/j.celrep.2019.03.070DOI Listing

The Vomeronasal System Can Learn Novel Stimulus Response Pairings.

Cell Rep 2019 Apr;27(3):676-684.e6

Hebrew University Medical School, Department of Medical Neurobiology, Institute of Medical Research Israel-Canada, Jerusalem 9112102, Israel. Electronic address:

Behavioral responses can be classified as innate or learned and are often mediated by distinct neuronal pathways. In many animals, chemical cues are crucial for directing behaviors, and multiple chemosensory subsystems serve this purpose. The major subsystems in vertebrates are the main olfactory system (MOS) and the vomeronasal system (VNS). Read More

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http://dx.doi.org/10.1016/j.celrep.2019.03.042DOI Listing

Expanding Knowledge of the Host Range of and Host Plant Preference of MEAM1.

Plant Dis 2019 Apr 17:PDIS11181941RE. Epub 2019 Apr 17.

2 United States Department of Agriculture-Agricultural Research Service, Salinas, CA, U.S.A.

The crinivirus (ToCV) is often found infecting tomato crops in Brazil, with variable incidence, but associated with prevalence of its primary vector, MEAM1. ToCV control is difficult because there are no resistant commercial tomato varieties or hybrids available and chemical spray for control of the whitefly vector has not been effective. The present study evaluated the partial host range of a Brazilian isolate of ToCV and the preference of MEAM1 for oviposition on those species identified as susceptible to the virus. Read More

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https://apsjournals.apsnet.org/doi/10.1094/PDIS-11-18-1941-R
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http://dx.doi.org/10.1094/PDIS-11-18-1941-REDOI Listing
April 2019
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Using Hydrogel to Diversify the Adaptability and Applicability of Functional Nanoparticles: from Nanotech-Flavored Jellies to Artificial Enzymes.

Langmuir 2019 Apr 17. Epub 2019 Apr 17.

The use of hydrogel to accommodate nanoparticles is generally aimed at synergetic integration of the peculiar electronic, photonic, magnetic, mechanical, and chemical properties of the nanoparticles with the stimuli-response of the hydrogels into unprecedented, smart, collective functions. The intrinsic water-borne nature of hydrogels further endorses the significant implications of such nanocomposites in biology and medicine. This article will be an account with accent on how to introduce nanoparticles within a hydrogel and to utilize the hydrogel to assist the nanoparticles to adapt themselves into different environments with a large span of polarity ranging from orthodox aqueous media to unorthodox organic ones. Read More

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http://dx.doi.org/10.1021/acs.langmuir.9b00254DOI Listing

Layer-stacking, defects and robust superconductivity on Mo-terminated surface of ultrathin Mo2C flakes grown by CVD.

Nano Lett 2019 Apr 17. Epub 2019 Apr 17.

Materials can exhibit exotic properties when they approach the two dimensional (2D) limit. Because of promising applications in catalysis and energy storage, 2D transition metal carbides (TMCs) have attracted considerable attention in recent years. Among these TMCs, ultrathin crystalline α-Mo2C flakes have been fabricated by chemical vapor deposition on Cu/Mo bilayer foils and their 2D superconducting property was revealed by transport measurement. Read More

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http://pubs.acs.org/doi/10.1021/acs.nanolett.9b00972
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http://dx.doi.org/10.1021/acs.nanolett.9b00972DOI Listing
April 2019
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When Current Does Not Follow Bonds: Current Density In Saturated Molecules.

J Phys Chem A 2019 Apr 17. Epub 2019 Apr 17.

The tools commonly used to understand structure-property relationships in molecular conductance, inter-atomic currents and conductance eigenchannels, generally give us a sense of familiarity, with the chemical bonding framework and molecular orbitals reflected in the current. Here we show that while this picture is true for conjugated molecules, it breaks down in saturated systems. We investigate the current density in saturated chains of alkanes, silanes and germanes and show that the current density does not follow the bonds, but rather the nuclei define the diameter of a pipe through which the current flows. Read More

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http://dx.doi.org/10.1021/acs.jpca.8b11092DOI Listing

Estimation of Shape, Volume, and Dipole Moment of Individual Proteins Freely Transiting a Synthetic Nanopore.

ACS Nano 2019 Apr 17. Epub 2019 Apr 17.

This paper demonstrates that high-bandwidth current recordings in combination with low-noise silicon nitride nanopores make it possible to determine the molecular volume, approximate shape, and dipole moment of single native proteins in solution without the need for labeling or other chemical modifications of these proteins. The analysis is based on current modulations caused by the translation and rotation of single proteins through a uniform electric field inside of a nanopore. We applied this technique to nine proteins and show that these measured protein parameters agree well with reference values, but only if the nanopore walls were coated with a non-stick fluid lipid bilayer. Read More

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http://dx.doi.org/10.1021/acsnano.8b09555DOI Listing

Evolutionary Trajectories for the Functional Diversification of Anthracycline Methyltransferases.

ACS Chem Biol 2019 Apr 17. Epub 2019 Apr 17.

Microbial natural products are an important source of chemical entities for drug discovery. Recent advances in understanding the biosynthesis of secondary metabolites has revealed how this rich chemical diversity is generated through functional differentiation of biosynthetic enzymes. For instance, investigations into anthracycline anti-cancer agents have uncovered distinct S-adenosyl methionine (SAM) - dependent proteins: DnrK is a 4-O-methyltransferase involved in daunorubicin biosynthesis, whereas RdmB (52% sequence identity) from the rhodomycin pathway catalyzes 10-hydroxylation. Read More

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http://pubs.acs.org/doi/10.1021/acschembio.9b00238
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http://dx.doi.org/10.1021/acschembio.9b00238DOI Listing
April 2019
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Scalable biosynthesis of the seaweed neurochemical kainic acid.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

University of California at San Diego, Scripps Institution of Oceanography, 9500 Gilman Dr., 92093-0204, La Jolla, UNITED STATES.

Kainic acid, the flagship member of the kainoid family of natural neurochemicals, is a widely used neuropharmacological agent that helped unravel the key role of ionotropic glutamate receptors, including the kainate receptor, in the central nervous system. Worldwide shortages of this seaweed natural product in 2000 prompted numerous chemical syntheses that now number in excess of 70, including scalable preparations with as few as six-steps. Herein we report the discovery and characterization of the concise two-enzyme biosynthetic pathway to kainic acid from L-glutamic acid and dimethylallyl pyrophosphate in red macroalgae and show that the biosynthetic genes are co-clustered in genomes of Digenea simplex and the edible Palmaria palmata. Read More

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http://dx.doi.org/10.1002/anie.201902910DOI Listing

RalA and RalB relocalization to depolarized mitochondria depends on clathrin-mediated endocytosis and facilitates TBK1 activation.

PLoS One 2019 17;14(4):e0214764. Epub 2019 Apr 17.

Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America.

Healthy mitochondria use an electrochemical gradient across the inner mitochondrial membrane (IMM) to generate energy in the form of ATP. A variety of endogenous and exogenous factors can lead to transient or sustained depolarization of the IMM, including mitochondrial fission events, expression of uncoupling proteins, electron transport chain (ETC) inhibitors, or chemical uncouplers. This depolarization in turn leads to a variety of physiological responses, ranging from selective mitochondrial clearance (mitophagy) to cell death. Read More

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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0214764PLOS

Coexistence of Different Charge Transfer Mechanisms in the Hot Carrier Dynamics of Hybrid Plasmonic Nanomaterials.

Nano Lett 2019 Apr 17. Epub 2019 Apr 17.

Hot-carrier dynamics at interfaces of semiconductors and nanoclusters is of significant importance for photovoltaic and photocatalytic applications. Plasmon-driven charge separation processes are considered to be only dependent on the type of donor-acceptor interactions, i.e. Read More

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http://dx.doi.org/10.1021/acs.nanolett.9b00647DOI Listing

Electrochemical Radical Formyloxylation-Bromination, -Chlorination, and -Trifluoromethylation of Alkenes.

Org Lett 2019 Apr 17. Epub 2019 Apr 17.

College of Chemistry and Chemical Engineering , Northwest Normal University , 967 Anning East Road , Lanzhou 730070 , China.

Given the versatility and value of the structurally diverse organohalides and CF-containing compounds in organic synthesis, we reported a green, oxidant-free electrochemical method using undivided electrochemical cells for radical bromination, chlorination and trifluoromethylation-formyloxylation of the various alkenes with readily available halogen radical (NaCl, NaBr), trifluoromethyl radical (CFSONa) sources, and DMF as formyloxylation reagents. The protocol is operationally simple and robust and the Cl, Br or CF was directly oxidized at the anode, obviating the need for exogenous chemical oxidants. Read More

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http://dx.doi.org/10.1021/acs.orglett.9b00867DOI Listing

Enantioselective Gold(I)-Catalyzed Heterocyclization-Intermolecular Exo [4 + 3]-Cycloaddition Reactions for the Synthesis of Chiral Oxa-Bridged Benzocycloheptanes.

Org Lett 2019 Apr 17. Epub 2019 Apr 17.

Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry , East China Normal University , 3663 North Zhongshan Road , Shanghai 200062 , P.R. China.

The highly exo- and enantioselective gold-catalyzed tandem heterocyclization/[4 + 3] cycloaddition of 2-(1-alkynyl)-2-alken-1-ones and 1,3-diphenylisobenzofuran was implemented by utilizing Ming-Phos, which provides a facile access to chiral seven-membered oxa-bridged rings in 80-98% yield with high exo selectivity ( exo/ endo up to 50:1) and up to 97% ee. Read More

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http://dx.doi.org/10.1021/acs.orglett.9b00537DOI Listing

Escherichia coli Strain Designed for Characterizing in Vivo Functions of Nicotinamide Adenine Dinucleotide Analogues.

Org Lett 2019 Apr 17. Epub 2019 Apr 17.

Division of Biotechnology , Dalian Institute of Chemical Physics , CAS, Dalian 116023 , China.

An Escherichia coli strain was constructed for the efficient import of nicotinamide adenine dinucleotide (NAD) analogues into cells by limiting extracellular degradation while expressing an efficient NAD importer. In vivo functions of three NAD analogues were characterized. Nicotinamide hypoxanthine dinucleotide was identified as an inhibitor of NAD synthesis. Read More

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http://dx.doi.org/10.1021/acs.orglett.9b00935DOI Listing

Azaindenocorannulenes: Synthesis, Properties, and Chirality.

Org Lett 2019 Apr 17. Epub 2019 Apr 17.

Health Science Platform , Tianjin University , 92 Weijin Road , Nankai District, Tianjin 300072 , P. R. China.

Palladium-catalyzed intramolecular arylation provides bowl-shaped azaindenocorannulenes 7-9. Crystals of 8 show bowl-in-bowl columnar stacking. A substituent model rationalizes the first reduction potential of 18 related molecular bowls. Read More

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http://pubs.acs.org/doi/10.1021/acs.orglett.9b00718
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http://dx.doi.org/10.1021/acs.orglett.9b00718DOI Listing
April 2019
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Extracellular DNA Provides Structural Integrity to a Micrococcus luteus Biofilm.

Langmuir 2019 Apr 17. Epub 2019 Apr 17.

Department of Physics and Astronomy , The University of Sheffield , Hounsfield Road , Sheffield S3 7RH , U.K.

Force spectroscopy was used to show that extracellular DNA (eDNA) has a pre-eminent structural role in a biofilm. The adhesive behavior of extracellular polymeric substances to poly(ethylene terephthalate), a model hydrophobic surface, was measured in response to their degradation by hydrolytic enzymes known for their biofilm dispersion potential: DNaseI, protease, cellulase, and mannanase. Only treatment with DNaseI significantly decreased the adhesive force of the model bacterium Micrococcus luteus with the surface, and furthermore this treatment almost completely eliminated any components of the biofilm maintaining the adhesion, establishing a key structural role for eDNA. Read More

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http://dx.doi.org/10.1021/acs.langmuir.9b00297DOI Listing

Excited-State Dynamics in the RNA Nucleotide Uridine 5'-Monophosphate Investigated using Femtosecond Broadband Transient Absorption Spectroscopy.

J Phys Chem Lett 2019 Apr 15. Epub 2019 Apr 15.

Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, however, investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5'-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Read More

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http://dx.doi.org/10.1021/acs.jpclett.9b00492DOI Listing

Estimated Long-term (1981-2016) Concentrations of Ambient Fine Particulate Matter across North America from Chemical Transport Modeling, Satellite Remote Sensing and Ground-based Measurements.

Environ Sci Technol 2019 Apr 17. Epub 2019 Apr 17.

Accurate data concerning historical fine particulate matter (PM2.5) concentrations are needed to assess long-term changes in exposure and associated health risks. We estimated historical PM2. Read More

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http://dx.doi.org/10.1021/acs.est.8b06875DOI Listing

Enzymatic reactions involving ketyls: From a chemical curiosity to a general biochemical mechanism.

Authors:
Wolfgang Buckel

Biochemistry 2019 Apr 17. Epub 2019 Apr 17.

Ketyls are radical anions with nucleophilic properties. Ketyls obtained by enzymatic one-electron reduction of thioesters were proposed as intermediates for the dehydration of ( R)-2-hydroxyacyl-CoA to ( E)-2-enoyl-CoA. This concept was extended to the Birch-like reduction of benzoyl-CoA to 1,5-cyclohexadienecarboxyl-CoA. Read More

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http://pubs.acs.org/doi/10.1021/acs.biochem.9b00171
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http://dx.doi.org/10.1021/acs.biochem.9b00171DOI Listing
April 2019
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Computer-Aided Design of Luminescent Linear N-Heterocyclic Carbene Copper(I) Pyridine Complexes.

Inorg Chem 2019 Apr 17. Epub 2019 Apr 17.

Faculty of Chemistry and Chemical Biology , TU Dortmund University , Otto-Hahn-Strasse 6 , D-44227 Dortmund , Germany.

Multireference configuration interaction methods including spin-orbit interactions have been employed to investigate the photophysical properties of various linear N-heterocyclic carbene (NHC) copper(I) pyridine complexes with the aim of designing performant thermally activated delayed fluorescence (TADF) emitters for use in organic-light-emitting diodes. Our theoretical results indicate that this structural motif is very favorable for generating excited triplet states with high quantum yield. The first excited singlet (S) and corresponding triplet state (T) are characterized by d → π metal-to-ligand charge-transfer (MLCT) excitations. Read More

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http://dx.doi.org/10.1021/acs.inorgchem.9b00334DOI Listing

Integration of Semiconductor Oxide and a Microporous (3,10)-Connected Co-Based Metal-Organic Framework for Enhanced Oxygen Evolution Reaction.

Inorg Chem 2019 Apr 17. Epub 2019 Apr 17.

College of Materials and Chemical Engineering, Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials , China Three Gorges University , Yichang , Hubei 443002 , China.

Developing high-efficiency and cost-effective electrocatalytic oxygen evolution reaction (OER) catalysts would determine the future distributions of energy conversion technologies. Metal-organic frameworks (MOFs), with unsaturated active metal sites, functionalized organic linkers, and large surface areas, are emerging heterogeneous electrocatalysts for the water oxidation process. Herein, we report an oxygen-evolving microporous (3,10)-connected Co-based MOF (denoted as CTGU-14) for the electrocatalytic OER. Read More

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http://dx.doi.org/10.1021/acs.inorgchem.9b00202DOI Listing

Nanowired Bioelectric Interfaces.

Chem Rev 2019 Apr 17. Epub 2019 Apr 17.

Department of Chemistry and Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States.

Biological systems have evolved biochemical, electrical, mechanical, and genetic networks to perform essential functions across various length and time scales. High-aspect-ratio biological nanowires, such as bacterial pili and neurites, mediate many of the interactions and homeostasis in and between these networks. Synthetic materials designed to mimic the structure of biological nanowires could also incorporate similar functional properties, and exploiting this structure-function relationship has already proved fruitful in designing biointerfaces. Read More

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http://dx.doi.org/10.1021/acs.chemrev.8b00795DOI Listing

Highly Oxidized Graphene Quantum Dots from Coal as Efficient Antioxidants.

ACS Appl Mater Interfaces 2019 Apr 17. Epub 2019 Apr 17.

Graphene quantum dots (GQDs) have recently been employed in various fields including medicine as antioxidants, primarily due to favorable biocompatibility in comparison to common inorganic quantum dots, although the structural features that lead to the biological activities of GQDs are poorly understood. Here we report that coal derived GQDs and their poly(ethylene glycol)-functionalized derivatives serve as efficient antioxidants, and we evaluate their electrochemical, chemical, and in vitro biological activity. Through the evaluation of scavenging abilities toward reactive oxygen species, we demonstrate correlation of π-conjugated stable radicals with activity. Read More

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http://dx.doi.org/10.1021/acsami.9b01082DOI Listing

Chemistry of Layered Pnictogens: Phosphorus, Arsenic, Antimony, and Bismuth.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technicka 5, 166 28, Prague 6, Czech Republic.

Materials with few layers have been subjected to extensive research for the last few decades owing to their remarkable properties as for example catalysts, optical and electrical devices, or sensors. The properties and electronic structure of these materials can be tailored by the introduction of substituents. In the case of more reactive species, the modification also can improve stability, which is also an important factor with respect to device fabrication. Read More

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http://dx.doi.org/10.1002/anie.201900811DOI Listing

β-Selective Aroylation of Activated Alkenes by Photoredox Catalysis.

Angew Chem Int Ed Engl 2019 Apr 17. Epub 2019 Apr 17.

Department of Chemistry and Institute of Chemical Biology and Drug Discovery, The State University of New York at Stony Brook, Stony Brook, NY, 11794, USA.

Late-stage synthesis of α,β-unsaturated aryl ketones remains an unmet challenge in organic synthesis. Reported herein is a photocatalytic non-chain-radical aroyl chlorination of alkenes by a 1,3-chlorine atom shift to form β-chloroketones as masked enones that liberate the desired enones upon workup. This strategy suppresses side reactions of the enone products. Read More

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http://doi.wiley.com/10.1002/anie.201901874
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http://dx.doi.org/10.1002/anie.201901874DOI Listing
April 2019
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Amide Synthesis from Thiocarboxylic Acids and Amines by Spontaneous Reaction and Electrosynthesis.

ChemSusChem 2019 Apr 17. Epub 2019 Apr 17.

CHINA.

Amide bond formation is one of the most important basic reactions in chemistry. A catalyst free approach for constructing amide bonds from thiocarboxylic acids and amines has been developed. The mechanistic studies showed that the disulfide is the key intermediate for this amide synthesis. Read More

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http://dx.doi.org/10.1002/cssc.201900814DOI Listing

Identification of natural compound inhibitors against PfDXR: A hybrid structure-based molecular modeling approach and molecular dynamics simulation studies.

J Cell Biochem 2019 Apr 17. Epub 2019 Apr 17.

Centre for Applied Chemistry, Central University of Gujarat, Gandhinagar, Gujarat, India.

In the present contribution, multicomplex-based pharmacophore studies were carried out on the structural proteome of Plasmodium falciparum 1-deoxy-D-xylulose-5-phosphate reductoisomerase. Among the constructed models, a representative model with complementary features, accountable for the inhibition was used as a primary filter for the screening of database molecules. Auxiliary evaluations of the screened molecules were performed via drug-likeness and molecular docking studies. Read More

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https://onlinelibrary.wiley.com/doi/abs/10.1002/jcb.28714
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http://dx.doi.org/10.1002/jcb.28714DOI Listing
April 2019
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Comparative light and scanning electron microscopy in authentication of adulterated traded medicinal plants.

Microsc Res Tech 2019 Apr 17. Epub 2019 Apr 17.

Department of Plant Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

The medicinal plants are utilized globally considering the cheap and chemical free source, but their correct identification and authentication is prerequisite for safety and efficacy of plant-based medicines. The present study encompassed traded medicinal plants (16) with high therapeutic value from diverse families like Brassicaceae, Berberidaceae, Malvaceae, Salicaceae, Myrtaceae, Papilionaceae, Ascelpiadaceae, Colchicaceae, Violaceae, and Vitaceae for detailed microscopic study of characters that is, morphology, pollen shape and sizes, P/E ratio, pore length and width, spine length, colpi dimensions, and exine sculpture pattern. The plants showed noteworthy differences in microscopy of Wattakaka volubilis having pollinia, translator and corpusculum like structures while pores were visible in Colchicum luteum, Alcea rosea, and Hibiscus syriacus. Read More

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http://dx.doi.org/10.1002/jemt.23266DOI Listing

SSDs Revisited: Part I - A Framework for Sample Size Guidance on Species Sensitivity Distribution Analysis.

Environ Toxicol Chem 2019 Apr 17. Epub 2019 Apr 17.

Environmental Stewardship, The Procter & Gamble Company, Mason Business Center, 8700 S. Mason-Montgomery Road, Mason, OH, USA.

This work proposes a framework on sample size for species sensitivity distribution analyses, with perspectives on Bayesian, frequentist, and even nonparametric approaches to estimation. A statistical sample size analysis intends to assure that the implementation of a statistical model will satisfy a minimum performance standard when relevant conditions are met. It requires that a statistical model be fully specified and how to measure its performance as a function of sample size. Read More

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http://dx.doi.org/10.1002/etc.4445DOI Listing

Hybrid analysis of gene dynamics predicts context specific expression and offers regulatory insights.

Bioinformatics 2019 Apr 17. Epub 2019 Apr 17.

Interdisciplinary Biological Sciences, Northwestern University, Evanston, IL.

Motivation: To understand the regulatory pathways underlying diseases, studies often investigate the differential gene expression between genetically or chemically differing cell populations. Differential expression analysis identifies global changes in transcription and enables the inference of functional roles of applied perturbations. This approach has transformed the discovery of genetic drivers of disease and possible therapies. Read More

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http://dx.doi.org/10.1093/bioinformatics/btz256DOI Listing

Determination of Ibuprofen and Phenylephrine in Tablets by High-Performance Thin Layer Chromatography and in Plasma by High-Performance Liquid Chromatography with Diode Array Detection.

J Chromatogr Sci 2019 Apr 17. Epub 2019 Apr 17.

Pharmaceutical Analysis Department, Faculty of Pharmacy, Damanhour University, 22511, Damanhour, Egypt.

Two chromatographic methods (high performance thin layer chromatography (HPTLC) and high performance liquid chromatography-diode array detector (HPLC-DAD)), were addressed for the analysis of a mixture consisted of phenylephrine hydrochloride and ibuprofen in two forms bulk and their combined dosage form. This binary mixture is considered to be a challenging one as the two drugs differ greatly in their chemical and physical properties. Not only this affects their simultaneous analysis, but also hinders their simultaneous extraction from biological fluids as plasma. Read More

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http://dx.doi.org/10.1093/chromsci/bmz031DOI Listing

A Brief Overview of HPLC-MS Analysis of Alkyl Methylphosphonic Acid Degradation Products of Nerve Agents.

Authors:
Clayton B'Hymer

J Chromatogr Sci 2019 Apr 17. Epub 2019 Apr 17.

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Division of Applied Research and Technology, 1090 Tusculum Avenue, Cincinnati, OH 45226, USA.

The analysis of degradation products from the classic chemical warfare nerve agents by high-performance liquid chromatography-mass spectrometry has been of much interest in recent years owing to the possible use as a terrorist weapon, and the incidents of chemical weapon usage in recent years in war torn countries. The alkyl methylphosphonic acid degradation products are of a particular interest, and they represent a specific chromatographic technical challenge for use in typical separation systems. Various published methods are summarized in this review and some of the problems associated with the analysis of these compounds are discussed. Read More

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http://dx.doi.org/10.1093/chromsci/bmz034DOI Listing

Root canal dressings for revascularization influence in vitro mineralization of apical papilla cells.

J Appl Oral Sci 2019 11;27:e20180396. Epub 2019 Apr 11.

Universidade de São Paulo, Faculdade de Odontologia, Departamento de Dentística, São Paulo, São Paulo, Brasil.

Endodontic revascularization is based on cell recruitment into the necrotic root canal of immature teeth after chemical disinfection. The clinical outcome depends on the ability of surviving cells from the apical tissue to differentiate and promote hard tissue deposition inside the dentinal walls.

Objective: To investigate the effect of calcium hydroxide (CH) and modified triple antibiotic paste (mTAP - ciprofloxacin, metronidazole and cefaclor) on the viability and mineralization potential of apical papilla cells (APC) in vitro . Read More

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http://dx.doi.org/10.1590/1678-7757-2018-0396DOI Listing
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