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Pesquisa : D01.268.150 [Categoria DeCS]
Referências encontradas : 43255 [refinar]
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  1 / 43255 MEDLINE  
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PMID:29408942
Autor:Slipher GA; Hairston WD; Bradford JC; Bain ED; Mrozek RA
Endereço:Vehicle Technologies Directorate, U.S. Army Research Laboratory, MD, United States of America.
Título:Carbon nanofiber-filled conductive silicone elastomers as soft, dry bioelectronic interfaces.
Fonte:PLoS One; 13(2):e0189415, 2018.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:Soft and pliable conductive polymer composites hold promise for application as bioelectronic interfaces such as for electroencephalography (EEG). In clinical, laboratory, and real-world EEG there is a desire for dry, soft, and comfortable interfaces to the scalp that are capable of relaying the µV-level scalp potentials to signal processing electronics. A key challenge is that most material approaches are sensitive to deformation-induced shifts in electrical impedance associated with decreased signal-to-noise ratio. This is a particular concern in real-world environments where human motion is present. The entire set of brain information outside of tightly controlled laboratory or clinical settings are currently unobtainable due to this challenge. Here we explore the performance of an elastomeric material solution purposefully designed for dry, soft, comfortable scalp contact electrodes for EEG that is specifically targeted to have flat electrical impedance response to deformation to enable utilization in real world environments. A conductive carbon nanofiber filled polydimethylsiloxane (CNF-PDMS) elastomer was evaluated at three fill ratios (3, 4 and 7 volume percent). Electromechanical testing data is presented showing the influence of large compressive deformations on electrical impedance as well as the impact of filler loading on the elastomer stiffness. To evaluate usability for EEG, pre-recorded human EEG signals were replayed through the contact electrodes subjected to quasi-static compressive strains between zero and 35%. These tests show that conductive filler ratios well above the electrical percolation threshold are desirable in order to maximize signal-to-noise ratio and signal correlation with an ideal baseline. Increasing fill ratios yield increasingly flat electrical impedance response to large applied compressive deformations with a trade in increased material stiffness, and with nominal electrical impedance tunable over greater than 4 orders of magnitude. EEG performance was independent of filler loading above 4 vol % CNF (< 103 ohms).
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:0 (Silicone Elastomers); 7440-44-0 (Carbon)


  2 / 43255 MEDLINE  
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PMID:29377926
Autor:Pan P; Zhao F; Ning J; Zhang L; Ouyang X; Zang H
Endereço:College of Forestry, Jiangxi Agricultural University, Nanchang, China.
Título:Impact of understory vegetation on soil carbon and nitrogen dynamic in aerially seeded Pinus massoniana plantations.
Fonte:PLoS One; 13(1):e0191952, 2018.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:Understory vegetation plays a vital role in regulating soil carbon (C) and nitrogen (N) characteristics due to differences in plant functional traits. Different understory vegetation types have been reported following aerial seeding. While aerial seeding is common in areas with serious soil erosion, few studies have been conducted to investigate changes in soil C and N cycling as affected by understory vegetation in aerially seeded plantations. Here, we studied soil C and N characteristics under two naturally formed understory vegetation types (Dicranopteris and graminoid) in aerially seeded Pinus massoniana Lamb plantations. Across the two studied understory vegetation types, soil organic C was significantly correlated with all measured soil N variables, including total N, available N, microbial biomass N and water-soluble organic N, while microbial biomass C was correlated with all measured variables except soil organic C. Dicranopteris and graminoid differed in their effects on soil C and N process. Except water-soluble organic C, all the other C and N variables were higher in soils with graminoids. The higher levels of soil organic C, microbial biomass C, total N, available N, microbial biomass N and water-soluble organic N were consistent with the higher litter and root quality (C/N) of graminoid vegetation compared to Dicranopteris. Changes in soil C and N cycles might be impacted by understory vegetation types via differences in litter or root quality.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:0 (Soil); 7440-44-0 (Carbon); N762921K75 (Nitrogen)


  3 / 43255 MEDLINE  
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PMID:28462910
Autor:Mihailescu IN; Bociaga D; Popescu-Pelin G; Stan GE; Duta L; Socol G; Chifiriuc MC; Bleotu C; Lazar V; Husanu MA; Zgura I; Miculescu F; Negut I; Hapenciuc C
Endereço:National Institute for Lasers, Plasma and Radiation Physics, 077125 Magurele, Romania.
Título:Optimized silicon reinforcement of carbon coatings by pulsed laser technique for superior functional biomedical surfaces fabrication.
Fonte:Biofabrication; 9(2):025029, 2017 Jun 01.
ISSN:1758-5090
País de publicação:England
Idioma:eng
Resumo:We report on the fabrication of silicon-reinforced carbon (C:Si) structures by combinatorial pulsed laser deposition to search for the best design for a new generation of multi-functional coated implants. The synthesized films were characterized from the morphological, structural, compositional, mechanical and microbiological points of view. Scanning electron microscopy revealed the presence, on top of the deposited layers, of spheroid particulates with sizes in the micron range. No micro-cracks or delaminations were observed. Energy dispersive x-ray spectroscopy and grazing incidence x-ray diffraction pointed to the existence of a C to Si compositional gradient from one end of the film to the other. Raman investigation revealed a relatively high sp hybridization of up to 80% at 40-48 mm apart from the edge with higher C content. Si addition was demonstrated to significantly increase C:Si film bonding to the substrate, with values above the ISO threshold for coatings to be used in high-loading biomedical applications. Surface energy studies pointed to an increase in the hydrophilic character of the deposited structures along with Si content up to 52 mN m . In certain cases, the Si-reinforced C coatings elicited an antimicrobial biofilm action. The presence of Si was proven to be benign to HEp-2 cells of human origin, without interfering with their cellular cycle. On this basis, reliable C:Si structures with good adherence to the substrate and high efficiency against microbial biofilms can be developed for implant coatings and other advanced medical devices.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Coated Materials, Biocompatible); 059QF0KO0R (Water); 7440-44-0 (Carbon); Z4152N8IUI (Silicon)


  4 / 43255 MEDLINE  
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PMID:28987406
Autor:Szewczyk R; Kusmierska A; Bernat P
Endereço:Department of Industrial Microbiology and Biotechnology, Institute of Microbiology, Biotechnology and Immunology, Faculty of Biology and Environmental Protection, University of Lódz, Banacha 12/16, 90-237 Lódz, Poland. Electronic address: rafal.szewczyk@biol.uni.lodz.pl.
Título:Ametryn removal by Metarhizium brunneum: Biodegradation pathway proposal and metabolic background revealed.
Fonte:Chemosphere; 190:174-183, 2018 Jan.
ISSN:1879-1298
País de publicação:England
Idioma:eng
Resumo:Ametryn is a representative of a class of s-triazine herbicides absorbed by plant roots and leaves and characterized as a photosynthesis inhibitor. It is still in use in some countries in the farming of pineapples, soybean, corn, cotton, sugar cane or bananas; however, due to the adverse effects of s-triazine herbicides on living organisms use of these pesticides in the European Union has been banned. In the current study, we characterized the biodegradation of ametryn (100 mg L ) by entomopathogenic fungal cosmopolite Metarhizium brunneum. Ametryn significantly inhibited the growth and glucose uptake in fungal cultures. The concentration of the xenobiotic drops to 87.75 mg L at the end of culturing and the biodegradation process leads to formation of four metabolites: 2-hydroxy atrazine, ethyl hydroxylated ametryn, S-demethylated ametryn and deethylametryn. Inhibited growth is reflected in the metabolomics data, where significant differences in concentrations of L-proline, gamma-aminobutyric acid, L-glutamine, 4-hydroxyproline, L-glutamic acid, ornithine and L-arginine were observed in the presence of the xenobiotic when compared to control cultures. The metabolomics data demonstrated that the presence of ametryn in the fungal culture induced oxidative stress and serious disruptions of the carbon and nitrogen metabolism. Our results provide deeper insights into the microorganism strategy for xenobiotic biodegradation which may result in future enhancements to ametryn removal by the tested strain.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Herbicides); 0 (Triazines); 1SPQ95183Y (ametryne); 3KX376GY7L (Glutamic Acid); 7440-44-0 (Carbon); 9DLQ4CIU6V (Proline); N762921K75 (Nitrogen); QJA9M5H4IM (Atrazine)


  5 / 43255 MEDLINE  
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PMID:28837871
Autor:Beltrame KK; Cazetta AL; de Souza PSC; Spessato L; Silva TL; Almeida VC
Endereço:Laboratory of Environmental and Agrochemistry, Agrochemistry, Department of Chemistry, The State University of Maringá, 5790 Colombo Avenue, CEP 87020-900-Maringá, Paraná, Brazil.
Título:Adsorption of caffeine on mesoporous activated carbon fibers prepared from pineapple plant leaves.
Fonte:Ecotoxicol Environ Saf; 147:64-71, 2018 Jan.
ISSN:1090-2414
País de publicação:Netherlands
Idioma:eng
Resumo:The present work reports the preparation of activated carbon fibers (ACFs) from pineapple plant leaves, and its application on caffeine (CFN) removal from aqueous solution. The preparation procedure was carried out using the H PO as activating agent and slow pyrolysis under N atmosphere. The characterization of materials was performed from the N adsorption and desorption isotherms, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, Boehm titration and pH method. ACFs showed high BET surface area value (S = 1031m g ), well-developed mesoporous structure (mesopore volume of 1.27cm³ g ) and pores with average diameter (D ) of 5.87nm. Additionally, ACFs showed features of fibrous material with predominance of acid groups on its surface. Adsorption studies indicated that the pseudo-second order kinetic and Langmuir isotherm models were that best fitted to the experimental data. The monolayer adsorption capacity was found to be 155.50mgg . thermodynamic studies revealed that adsorption process is spontaneous, exothermic and occurs preferably via physisorption. The pineapple leaves are an efficient precursor for preparation of ACFs, which were successful applied as adsorbent material for removal of caffeine from the aqueous solutions.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Water Pollutants, Chemical); 0 (carbon fiber); 16291-96-6 (Charcoal); 3G6A5W338E (Caffeine); 7440-44-0 (Carbon)


  6 / 43255 MEDLINE  
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PMID:29422671
Autor:Li C; Zhang B; Chen B; Ji L; Yu H
Endereço:Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore.
Título:Site-specific phosphorylation of TRANSPARENT TESTA GLABRA1 mediates carbon partitioning in Arabidopsis seeds.
Fonte:Nat Commun; 9(1):571, 2018 02 08.
ISSN:2041-1723
País de publicação:England
Idioma:eng
Resumo:Seed development is dependent on nutrients, such as a source of carbon, supplied by the parent plant. It remains largely unknown how these nutrients are distributed to zygotic and maternal tissues to coordinate storage of reserve compounds and development of protective tissues like seed coat. Here we show that phosphorylation of TRANSPARENT TESTA GLABRA1 (TTG1) is regulated by SHAGGY-like kinases 11/12 (SK11/12) and that this mediates carbon flow to fatty acid synthesis and seed coat traits in Arabidopsis seeds. SK11/12 phosphorylate TTG1 at serine 215, thus preventing TTG1 interaction with TRANSPARENT TESTA2. This compromises recruitment of TTG1 to the GLABRA2 locus and downregulates GLABRA2 expression, which enhances biosynthesis of fatty acids in the embryo, but reduces production of mucilage and flavonoid pigments in the seed coat. Therefore, site-specific phosphorylation of TTG1 by SK11/SK12 regulates carbon partitioning between zygotic and maternal sinks in seeds.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:0 (Arabidopsis Proteins); 0 (Fatty Acids); 0 (Flavonoids); 0 (Isoenzymes); 0 (Plant Mucilage); 0 (TTG1 protein, Arabidopsis); 0 (TTG2 protein, Arabidopsis); 0 (Transcription Factors); 7440-44-0 (Carbon); EC 2.7.11.26 (ATSK11 protein, Arabidopsis); EC 2.7.11.26 (Glycogen Synthase Kinase 3)


  7 / 43255 MEDLINE  
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PMID:29335469
Autor:Aunkham A; Zahn M; Kesireddy A; Pothula KR; Schulte A; Baslé A; Kleinekathöfer U; Suginta W; van den Berg B
Endereço:Biochemistry-Electrochemistry Research Unit, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.
Título:Structural basis for chitin acquisition by marine Vibrio species.
Fonte:Nat Commun; 9(1):220, 2018 01 15.
ISSN:2041-1723
País de publicação:England
Idioma:eng
Resumo:Chitin, an insoluble polymer of N-acetylglucosamine, is one of the most abundant biopolymers on Earth. By degrading chitin, chitinolytic bacteria such as Vibrio harveyi are critical for chitin recycling and maintenance of carbon and nitrogen cycles in the world's oceans. A decisive step in chitin degradation is the uptake of chito-oligosaccharides by an outer membrane protein channel named chitoporin (ChiP). Here, we report X-ray crystal structures of ChiP from V. harveyi in the presence and absence of chito-oligosaccharides. Structures without bound sugar reveal a trimeric assembly with an unprecedented closing of the transport pore by the N-terminus of a neighboring subunit. Substrate binding ejects the pore plug to open the transport channel. Together with molecular dynamics simulations, electrophysiology and in vitro transport assays our data provide an explanation for the exceptional affinity of ChiP for chito-oligosaccharides and point to an important role of the N-terminal gate in substrate transport.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:0 (Bacterial Outer Membrane Proteins); 0 (Oligosaccharides); 0 (Porins); 1398-61-4 (Chitin); 7440-44-0 (Carbon); N762921K75 (Nitrogen); V956696549 (Acetylglucosamine)


  8 / 43255 MEDLINE  
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PMID:29311545
Autor:Chrachri A; Hopkinson BM; Flynn K; Brownlee C; Wheeler GL
Endereço:Marine Biological Association, Plymouth, PL1 2PB, UK.
Título:Dynamic changes in carbonate chemistry in the microenvironment around single marine phytoplankton cells.
Fonte:Nat Commun; 9(1):74, 2018 01 08.
ISSN:2041-1723
País de publicação:England
Idioma:eng
Resumo:Photosynthesis by marine diatoms plays a major role in the global carbon cycle, although the precise mechanisms of dissolved inorganic carbon (DIC) uptake remain unclear. A lack of direct measurements of carbonate chemistry at the cell surface has led to uncertainty over the underlying membrane transport processes and the role of external carbonic anhydrase (eCA). Here we identify rapid and substantial photosynthesis-driven increases in pH and [CO ] primarily due to the activity of eCA at the cell surface of the large diatom Odontella sinensis using direct simultaneous microelectrode measurements of pH and CO along with modelling of cell surface inorganic carbonate chemistry. Our results show that eCA acts to maintain cell surface CO concentrations, making a major contribution to DIC supply in O. sinensis. Carbonate chemistry at the cell surface is therefore highly dynamic and strongly dependent on cell size, morphology and the carbonate chemistry of the bulk seawater.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
Nome de substância:0 (Carbonates); 142M471B3J (Carbon Dioxide); 7440-44-0 (Carbon); EC 4.2.1.1 (Carbonic Anhydrases)


  9 / 43255 MEDLINE  
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PMID:28968514
Autor:Huang Y; Li P; Chen G; Peng L; Chen X
Endereço:Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, No.500 Dong Chuan Road, Shanghai 200241, PR China.
Título:The production of cyanobacterial carbon under nitrogen-limited cultivation and its potential for nitrate removal.
Fonte:Chemosphere; 190:1-8, 2018 Jan.
ISSN:1879-1298
País de publicação:England
Idioma:eng
Resumo:Harmful cyanobacterial blooms (CyanoHABs) represent a serious threat to aquatic ecosystems. A beneficial use for these harmful microorganisms would be a promising resolution of this urgent issue. This study applied a simple method, nitrogen limitation, to cultivate cyanobacteria aimed at producing cyanobacterial carbon for denitrification. Under nitrogen-limited conditions, the common cyanobacterium, Microcystis, efficiently used nitrate, and had a higher intracellular C/N ratio. More importantly, organic carbons easily leached from its dry powder; these leachates were biodegradable and contained a larger amount of dissolved organic carbon (DOC) and carbohydrates, but a smaller amount of dissolved total nitrogen (DTN) and proteins. When applied to an anoxic system with a sediment-water interface, a significant increase of the specific NO -N removal rate was observed that was 14.2 times greater than that of the control. This study first suggests that nitrogen-limited cultivation is an efficient way to induce organic and carbohydrate accumulation in cyanobacteria, as well as a high C/N ratio, and that these cyanobacteria can act as a promising carbon source for denitrification. The results indicate that application as a carbon source is not only a new way to utilize cyanobacteria, but it also contributes to nitrogen removal in aquatic ecosystems, further limiting the proliferation of CyanoHABs.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Nitrates); 7440-44-0 (Carbon); N762921K75 (Nitrogen)


  10 / 43255 MEDLINE  
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PMID:28462789
Autor:Ren J; Sang Y; Lu J; Yao YF
Endereço:Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
Título:Protein Acetylation and Its Role in Bacterial Virulence.
Fonte:Trends Microbiol; 25(9):768-779, 2017 Sep.
ISSN:1878-4380
País de publicação:England
Idioma:eng
Resumo:Protein acetylation is a universal post-translational modification which is found in both eukaryotes and prokaryotes. This process is achieved enzymatically by the protein acetyltransferase Pat, and nonenzymatically by metabolic intermediates (e.g., acetyl phosphate) in bacteria. Protein acetylation plays a role in bacterial chemotaxis, metabolism, DNA replication, and other cellular processes. Recently, accumulating evidence has suggested that protein acetylation might be involved in bacterial virulence because a number of bacterial virulence factors are acetylated. In this review, we summarize the progress in understanding bacterial protein acetylation and discuss how it mediates bacterial virulence.
Tipo de publicação: JOURNAL ARTICLE; REVIEW
Nome de substância:0 (Bacterial Proteins); 0 (Proteins); 7440-44-0 (Carbon); EC 2.3.1.- (Acetyltransferases); EC 2.3.1.- (protein acyltransferase); N762921K75 (Nitrogen)



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