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https://www.readbyqxmd.com/read/29667747/self-assembled-cyclic-structures-from-copper-ii-peptoids
#1
Totan Ghosh, Natalia Fridman, Monica Kosa, Galia Maayan
Metal-ligand coordination is a key interaction in the self-assembly of biopolymers. Although binding of metal ions to synthetic proteins and peptides is known to yield high-order structures, self-assembly of peptidomimetic molecules upon metal binding is still challenging. Herein we explore the self-assembly of three peptoid trimers 3, 3A and 3B, bearing a bipyridine ligand at their C-terminus, a benzyl group at their N-terminus and a polar group (N-ethyl-R) in the middle position (R = OH, OCH3 and NH2, respectively) by Cu2+ coordination...
April 18, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29667683/nfsi-participated-intermolecular-aminoazidation-of-alkene-through-iron-catalysis
#2
Bowen Lei, Xiaojiao Wang, Lifang Ma, Yan Li, Ziyuan Li
An iron-catalysed intermolecular vicinal aminoazidation of alkenes, using N-fluorobenzenesulfonimide (NFSI) and trimethylsilyl azide (TMSN3) as the imidating and azidating reagents, respectively, is described, which could potentially provide a valuable route toward diverse vicinal diamine derivatives of great significance in medicinal chemistry and organic synthesis. Such iron-catalysed aminative bisfunctionalization of alkenes with NFSI has not been reported yet. Comparing to previously employed copper or palladium catalysts, the iron catalyst, FeCl2, was demonstrated to be a good alternative for its comparable efficiency and broad alkene scope...
April 18, 2018: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/29667659/correction-copper-mediated-regioselective-c-h-etherification-of-naphthylamides-with-arylboronic-acids-using-water-as-an-oxygen-source
#3
Subhasish Roy, Sourav Pradhan, Tharmalingam Punniyamurthy
Correction for 'Copper-mediated regioselective C-H etherification of naphthylamides with arylboronic acids using water as an oxygen source' by Subhasish Roy et al., Chem. Commun., 2018, DOI: 10.1039/c8cc02158a.
April 18, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29667527/comparison-of-the-physical-and-chemical-characteristics-of-fine-road-dust-at-different-urban-sites
#4
Kwang Yul Lee, Tsatsral Batmunkh, Hung Soo Joo, Kihong Park
The size distribution and chemical components of a fine fraction (<2.5 μm) of road dust collected at urban sites in Korea (Gwangju) and Mongolia (Ulaanbaatar) where distinct urban characteristics exist were measured. A clear bimodal size distribution was observed for the resuspended fine road dust at the urban sites in Korea. The first mode peaked at 100-110 nm, and the second peak was observed at 435-570 nm. Ultrafine mode (~30 nm) was found for the fine road dust at the Mongolia site, which was significantly affected by residential coal/biomass burning...
April 18, 2018: Journal of the Air & Waste Management Association
https://www.readbyqxmd.com/read/29667213/photosynthesis-is-differently-regulated-during-and-after-copper-induced-nutritional-stress-in-citrus-trees
#5
Franz W R Hippler, Veronica L Dovis, Rodrigo M Boaretto, Jose A Quaggio, Ricardo A Azevedo, Lorraine E Williams, Dirceu Mattos
Antioxidant enzymatic responses in Citrus leaves under Cu-induced stress depends on rootstock genotypes. However, there is a lack of information about how woody plants recover growth capacity after exposure to elevated Cu and whether growth is affected by the redistribution of the metal to new vegetative parts and consequently whether photosynthesis is affected. Therefore, the biomass of plants and Cu concentrations in new leaf flushes were determined in young citrus trees grafted onto contrasting rootstocks [Swingle citrumelo (SW) and Rangpur lime (RL)]...
April 17, 2018: Physiologia Plantarum
https://www.readbyqxmd.com/read/29666607/exploring-biogeochemistry-and-microbial-diversity-of-extant-microbialites-in-mexico-and-cuba
#6
Patricia M Valdespino-Castillo, Ping Hu, Martín Merino-Ibarra, Luz M López-Gómez, Daniel Cerqueda-García, Roberto González-De Zayas, Teresa Pi-Puig, Julio A Lestayo, Hoi-Ying Holman, Luisa I Falcón
Microbialites are modern analogs of ancient microbial consortia that date as far back as the Archaean Eon. Microbialites have contributed to the geochemical history of our planet through their diverse metabolic capacities that mediate mineral precipitation. These mineral-forming microbial assemblages accumulate major ions, trace elements and biomass from their ambient aquatic environments; their role in the resulting chemical structure of these lithifications needs clarification. We studied the biogeochemistry and microbial structure of microbialites collected from diverse locations in Mexico and in a previously undescribed microbialite in Cuba...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29666274/vibrations-of-a-molecule-in-an-external-force-field
#7
Norio Okabayashi, Angelo Peronio, Magnus Paulsson, Toyoko Arai, Franz J Giessibl
The oscillation frequencies of a molecule on a surface are determined by the mass distribution in the molecule and the restoring forces that occur when the molecule bends. The restoring force originates from the atomic-scale interaction within the molecule and with the surface, which plays an essential role in the dynamics and reactivity of the molecule. In 1998, a combination of scanning tunneling microscopy with inelastic tunneling spectroscopy revealed the vibrational frequencies of single molecules adsorbed on a surface...
April 16, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29666254/-shewanella-oneidensis-as-a-living-electrode-for-controlled-radical-polymerization
#8
Gang Fan, Christopher M Dundas, Austin J Graham, Nathaniel A Lynd, Benjamin K Keitz
Metabolic engineering has facilitated the production of pharmaceuticals, fuels, and soft materials but is generally limited to optimizing well-defined metabolic pathways. We hypothesized that the reaction space available to metabolic engineering could be expanded by coupling extracellular electron transfer to the performance of an exogenous redox-active metal catalyst. Here we demonstrate that the electroactive bacterium Shewanella oneidensis can control the activity of a copper catalyst in atom-transfer radical polymerization (ATRP) via extracellular electron transfer...
April 16, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29665956/laccase-production-in-bioreactor-scale-under-saline-condition-by-the-marine-derived-basidiomycete-peniophora-sp-cbmai-1063
#9
Pedro H Mainardi, Valker A Feitosa, Livia B Brenelli de Paiva, Rafaella C Bonugli-Santos, Fabio M Squina, Adalberto Pessoa, Lara D Sette
Laccase production in saline conditions is still poorly studied. The aim of the present study was to investigate the production of laccase in two different types of bioreactors by the marine-derived basidiomycete Peniophora sp. CBMAI 1063. The highest laccase activity and productivity were obtained in the Stirred Tank (ST) bioreactor, while the highest biomass concentration in Air-lift (AL) bioreactor. The main laccase produced was purified by ion exchange and size exclusion chromatography and appeared to be monomeric with molecular weight of approximately 55 kDa...
May 2018: Fungal Biology
https://www.readbyqxmd.com/read/29665767/nano-cuo-impairs-spatial-cognition-associated-with-inhibiting-hippocampal-ltp-via-affecting-glutamatergic-neurotransmission-in-rats
#10
Xiaoliang Li, Wei Sun, Lei An
Manufactured metal nanoparticles and their applications are continuously expanding because of their unique characteristics while their increasing use may predispose to potential health problems. Several studies have reported the adverse effects of copper oxide nanoparticles (nano-CuO) relative to ecotoxicity and cell toxicity, whereas little is known about the neurotoxicity of nano-CuO. The present study aimed to examine its effects on spatial cognition, hippocampal function, and the possible mechanisms. Male Wistar rats were used to establish an animal model, and nano-CuO was administered at a dose of 0...
January 1, 2018: Toxicology and Industrial Health
https://www.readbyqxmd.com/read/29665532/operating-optimization-for-the-heavy-metal-removal-from-the-municipal-solid-waste-incineration-fly-ashes-in-the-three-dimensional-electrokinetics
#11
Tao Huang, Longfei Liu, Lulu Zhou, Ke Yang
The three-dimensional (3D) electrode has been widely studied and curiously pushed forward for the treatment of various wastewater. However, the reports on the electro-remediation of municipal solid waste incineration fly ashes using 3D electrochemical platform are scarce. In this research, the removal of heavy metals from the municipal solid waste incineration fly ashes was comprehensively investigated using a 3D electrokinetic system. Central composite design method was used based on the 31 trials and desirability functions in the 3D electrochemical process to evaluate the main effect and their interacted effect of parameter-variables on the remedial efficiencies...
April 13, 2018: Chemosphere
https://www.readbyqxmd.com/read/29665484/removal-of-the-commercial-pesticides-novadim-progress-bordeaux-mixture-and-karate-zeon-by-pullulan-derivatives-based-flocculants
#12
Luminita Ghimici, Marieta Constantin
Cationic pullulan derivatives have been synthesized and evaluated, for the first time, as flocculants for the separation of the commercial pesticides, Novadim Progress (organophosphoric type), Bordeax mixture and Karate Zeon (pyrethroid type) from synthetic wastewater. The investigated polymer samples contained either pendent tertiary amine or quaternary ammonium salts groups. The separation efficiency was followed by UV-Vis spectroscopy, while the information regarding the mechanism involved in the separation of pesticide particles have been obtained by zeta potential...
April 14, 2018: Journal of Environmental Management
https://www.readbyqxmd.com/read/29665388/expression-and-characterization-of-novel-laccase-gene-from-pandoraea-sp-istkb-and-its-application
#13
Madan Kumar, Arti Mishra, Shashi Shekhar Singh, Shaili Srivastava, Indu Shekhar Thakur
In the present study, a non-blue laccase gene from previously reported lignin degrading bacterium, Pandoraea sp. ISTKB, was isolated, cloned and expressed in E. coli. Bioinformatics analysis of sequence discovered twin-arginine translocation signal sequence, copper binding motifs and presence of more random coil compare to helices and sheets in structure. The enzyme was found to be active on wide pH range and the pH optima was observed at pH 4 and 8 on substrate 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and 2,6-Dimethoxyphenol respectively...
April 14, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29665358/hyperinsulinemic-euglycemic-clamp-over-the-first-year-of-use-of-depot-medroxyprogesterone-acetate-as-a-contraceptive
#14
Vaneska Melhado-Kimura, Gisele Almeida Batista, Aglécio Luiz de Souza, Priscilla de Nazaré Silva Dos Santos, Sarah Monte Alegre, Elizabeth João Pavin, Luis Bahamondes, Arlete Fernandes
OBJECTIVE: The literature lacks data on the use of the gold-standard hyperinsulinemic-euglycemic clamp (HEC) technique for the evaluation of insulin resistance (IR) in depot-medroxyprogesterone acetate (DMPA) users. This study assessed carbohydrate metabolism in non-obese users of DMPA using the HEC technique. STUDY DESIGN: A prospective, non-randomized, comparative study conducted at the Family Planning Clinic/Metabolic Unit, University of Campinas, Brazil. Forty-eight women aged 18-39 years underwent HEC: 30 initiating use of DMPA and 18 initiating use of a copper intrauterine device (IUD)...
April 14, 2018: Contraception
https://www.readbyqxmd.com/read/29665217/ultrahigh-conductive-copper-large-flake-size-graphene-heterostructure-thin-film-with-remarkable-electromagnetic-interference-shielding-effectiveness
#15
Zhe Wang, Boyang Mao, Qianlong Wang, Jun Yu, Jixiang Dai, Rongguo Song, Zonghua Pu, Daping He, Zhi Wu, Shichun Mu
To guarantee the normal operation of next generation portable electronics and wearable devices, together with avoiding electromagnetic wave pollution, it is urgent to find a material possessing flexibility, ultrahigh conductive, and superb electromagnetic interference shielding effectiveness (EMI SE) simultaneously. In this work, inspired by a building bricks toy with the interlock system, we design and fabricate a copper/large flake size graphene (Cu/LG) composite thin film (≈8.8 μm) in the light of high temperature annealing of a large flake size graphene oxide film followed by magnetron sputtering of copper...
April 17, 2018: Small
https://www.readbyqxmd.com/read/29665144/disulfiram-copper-targets-stem-cell-like-aldh-population-of-multiple-myeloma-by-inhibition-of-aldh1a1-and-hedgehog-pathway
#16
Na Jin, Xiaojian Zhu, Fanjun Cheng, Liling Zhang
Multiple myeloma stem cells (MMSCs) have been considered as the major cause resulting in relapse. Eradicating MMSCs may be an effective strategy to improve the outcome of multiple myeloma (MM). Increased activity of aldehyde dehydrogenase (ALDH) has been found in MMSCs, but whether inhibiting ALDH activity can eliminate MMSCs remains unknown. Disulfiram (DS) has been reported as an inhibitor of ALDH, and increasing studies showed it has anti-cancer effects in a copper (Cu)-dependent manner. In this study, we isolated ALDH+ cells of MM by Aldefluor assay and demonstrated they possessed tumorigenesis capacities in vitro and in vivo...
April 17, 2018: Journal of Cellular Biochemistry
https://www.readbyqxmd.com/read/29665113/switchable-synthesis-of-z-homoallylic-boronates-and-e-allylic-boronates-by-enantioselective-copper-catalyzed-1-6-boration
#17
Yunfei Luo, Steven M Wales, Stamatis E Korkis, Iain D Roy, William Lewis, Hon Wai Lam
The enantioselective Cu-catalyzed 1,6-boration of (E,E)-α,β,γ,δ-unsaturated ketones is described, which gives homoallylic boronates with high enantiomeric purity and unexpectedly high Z-selectivity. By changing the solvent, the outcome can be altered to give E-allylic boronates.
April 17, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29664601/difluorocarbene-as-a-building-block-for-consecutive-bond-forming-reactions
#18
Alexander D Dilman, Vitalij V Levin
Compounds containing a difluoromethylene unit have gained increasing attention due to their utility in drug design. Classic methods for the synthesis of these compounds rely on either harsh deoxofluorination reactions or laborious functional group manipulation sequences. In 2013, we proposed a method for assembling gem-difluorinated molecules from a difluorocarbene, a nucleophile, and an electrophile. In this process, a difluorocarbene can be considered an equivalent of a bipolar CF2 unit. Performing consecutive bond-forming reactions by sequential attachment of a nucleophile and an electrophile to a difluorocarbene provides the opportunity for the synthesis of a wide variety of organofluorine compounds...
April 17, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29664305/copper-catalyzed-oxygenation-approach-to-oxazoles-from-amines-alkynes-and-molecular-oxygen
#19
Jun Pan, Xinyao Li, Xu Qiu, Xiao Luo, Ning Jiao
A novel and efficient oxygenation approach to trisubstituted oxazoles via a copper-catalyzed aerobic oxidative dehydrogenative annulation of amines, alkynes, and O2 has been developed. This transformation combines dioxygen activation and oxidative C-H bond functionalization and provides a practical protocol for the preparation of oxazole derivatives, which are privileged units found in various bioactive compounds or other natural products. 18 O-labeling experiments were conducted to reveal that oxygenation was involved in this chemistry...
April 17, 2018: Organic Letters
https://www.readbyqxmd.com/read/29664297/copper-catalyzed-synthesis-of-multisubstituted-indoles-through-tandem-ullmann-type-c-n-formation-and-cross-dehydrogenative-coupling-reactions
#20
Yue Li, Jinsong Peng, Xin Chen, Baichuan Mo, Xue Li, Peng Sun, Chunxia Chen
Multisubstituted indoles were synthesized via a one-pot tandem copper-catalyzed Ullmann-type C-N bond formation/intramolecular cross-dehydrogenative coupling process at 130 ℃ in DMSO. The methodology allows practical and modular assembly of indoles in good to excellent yields from readily available aryl iodides and enamines.
April 17, 2018: Journal of Organic Chemistry
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