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91.
Bernhard Kienesberger Beate Obermüller Georg Singer Barbara Mittl Reingard Grabherr Sigrid Mayrhofer Stefan Heinl Vanessa Stadlbauer Angela Horvath Wolfram Miekisch Patricia Fuchs Ingeborg Klymiuk Holger Till Christoph Castellani 《International journal of molecular sciences》2021,22(12)
We aimed to assess the in vitro antimicrobial activity and the in vivo effect on the murine fecal microbiome and volatile organic compound (VOC) profile of (S)-reutericyclin. The antimicrobial activity of (S)-reutericyclin was tested against Clostridium difficile, Listeria monocytogenes, Escherichia coli, Enterococcus faecium, Staphylococcus aureus, Staphylococcus (S.) epidermidis, Streptococcus agalactiae, Pseudomonas aeruginosa and Propionibacterium acnes. Reutericyclin or water were gavage fed to male BALBc mice for 7 weeks. Thereafter stool samples underwent 16S based microbiome analysis and VOC analysis by gas chromatography mass spectrometry (GC-MS). (S)-reutericyclin inhibited growth of S. epidermidis only. Oral (S)-reutericyclin treatment caused a trend towards reduced alpha diversity. Beta diversity was significantly influenced by reutericyclin. Linear discriminant analysis Effect Size (LEfSe) analysis showed an increase of Streptococcus and Muribaculum as well as a decrease of butyrate producing Ruminoclostridium, Roseburia and Eubacterium in the reutericyclin group. VOC analysis revealed significant increases of pentane and heptane and decreases of 2,3-butanedione and 2-heptanone in reutericyclin animals. The antimicrobial activity of (S)-reutericyclin differs from reports of (R)-reutericyclin with inhibitory effects on a multitude of Gram-positive bacteria reported in the literature. In vivo (S)-reutericyclin treatment led to a microbiome shift towards dysbiosis and distinct alterations of the fecal VOC profile. 相似文献
92.
Rafael S. Pinto João P. Serra João C. Barbosa Renato Gonçalves Maria M. Silva Senentxu Lanceros-Méndez Carlos M. Costa 《大分子材料与工程》2021,306(11):2100372
Considering the high levels of materials used in the fields of electronics and energy storage systems, it is increasingly necessary to take into consideration environmental impact. Thus, it is important to develop devices based on environmentally friendlier materials and/or processes, such as additive manufacturing techniques. In this work, poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) are prepared by direct-ink-writing (DIW) by varying solvent evaporation temperature and fill density percentage. Different morphologies for both polymers are obtained, including dense films and porous membranes, as well as different electroactive β-phase content, thermal and mechanical properties. The dielectric constant and piezoelectric d33 coefficient for dense films reaches up to 16 at 1 kHz and 4 pC N−1, respectively for PVDF-HFP with a fill density of 80 and a solvent evaporation temperature of 50 °C. Porous structures are developed for battery separator membranes in lithium-ion batteries, with a highest ionic conductivity value of 3.8 mS cm−1 for the PVDF-HFP sample prepared with a fill density of 100 and a solvent evaporation temperature of 25 °C, the sample showing an excellent cycling performance. It is demonstrated that electroactive films and membranes can be prepared by direct-ink writing suitable for sensors/actuators and energy storage systems. 相似文献
93.
A. H. Bott J. C. Suita A. G. da Silva P. E. V. de Miranda 《Surface & coatings technology》1995,70(2-3):257-260
1H(,p) 4He scattering cross-sections were determined for the 6.5–13 MeV (incident energy) range, thereby extending the energy range for such data beyond that available in the literature. These values are essential for the further development of hydrogen concentration profiling by the transmission elastic recoil detection technique, of particular interest in the design of surface-engineered hydrogen contamination barriers for steels. 相似文献
94.
Joo Batista A. Silva Regina C. M. de Paula Judith P. A. Feitosa Eduardo Diogo Gurgel‐Filho Claudio Maniglia‐Ferreira Francisco Jose de Souza Filho 《应用聚合物科学杂志》2006,100(5):4082-4088
Gutta‐percha cone is the most widely used material for root canal filling. The in vivo aging of this cone focus on the degradation of its main organic component, trans‐1,4‐polyisoprene, was studied. Aged cones (25 samples) from 2 to 30 years of root canal filling were extracted from different patients in the occasion of retreatment by mechanical way. The information about the aging time was given by the patients. Gel‐permeation chromatography (GPC) and infrared spectroscopy (FTIR) were the analytical techniques used. Polyisoprene degrades with time of aging, but in a slow process. Decrease in polymer molar mass from 5.7 × 105 to 1.7 × 105 g/mol was observed in polyisoprene from cone after 30 years of root canal filling and inside a noninfected tooth. In tooth with caries and periodontal infection, the decrease in molar mass is higher (4.6 × 104 g/mol in cone with 10 years of aging). The production of carbonyl and hydroxyl groups in the aged material indicates that the process is oxidative, even in closed teeth. In these cases, the oxygen could be provided from tissue fluid. The degradation mechanism is complex and depends on many factors, besides time of root canal filling. The dental problem caused by the aging could be the production and migration of cytotoxic substances to periodontal ligament and the reduction on the canal sealing property due to the polymer weight loss. Both of them could contribute to the root canal treatment failure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:4082–4088, 2006 相似文献
95.
Manuel Belmonte Vitor A. Silva Antonio José Fernandes Florinda Costa Rui Silva 《Journal of the American Ceramic Society》2003,86(5):749-754
The efficiency of different surface pretreatments (four standard chemical etchings and four diamond powder abrasive procedures) on silicon nitride (Si3 N4 ) substrates for chemical vapor deposition (CVD) of diamond has been systematically investigated. Blank Si3 N4 samples were polished with colloidal silica (∼0.25 μm). Diamond nucleation and growth runs were conducted in a microwave plasma chemical vapor deposition apparatus for 10 min and 6 h, respectively. Superior results concerning nucleation density ( N d ∼ 1010 cm−2 after 10 min), film uniformity, and grain size (below 2 μm after 6 h) were obtained for the mechanically microflawed samples, revealing that chemical etchings (hot and cold strong acids, molten base or CF4 plasma) are not crucial for good CVD diamond quality on Si3 N4 . 相似文献
96.
Marsaro AL Souza RC Della Lucia TM Fernandes JB Silva MF Vieira PC 《Journal of chemical ecology》2004,30(9):1771-1780
The response of Atta sexdens rubropilosa Forel workers to essential oils, epicuticular wax and hexane, dichloromethane, ethyl acetate, and methanol extracts of Eucalyptus maculata was evaluated. Hexane extracts of E. maculata interfered with the recognition mechanism among workers. The main active compounds identified from this plant were the sesquiterpenes elemol and beta-eudesmol. These compounds may be responsible for the resistance of this species to ant attack. 相似文献
97.
Catalysts based in cerium oxide for wet oxidation of acrylic acid in the prevention of environmental risks 总被引:3,自引:0,他引:3
Adrin M. T. Silva Rita R. N. Marques Rosa M. Quinta-Ferreira 《Applied catalysis. B, Environmental》2004,47(4):269-279
Acrylic acid is a refractory compound for the non-catalytic wet oxidation (WO) process and can seriously damage the environment when released in industrial effluents. Oxidation of acrylic acid by catalytic wet oxidation (CWO) was studied in slurry conditions in a high-pressure batch reactor at 200 °C and 15 bar of oxygen partial pressure. Several solid cerium-based catalysts prepared in our laboratory were used (Ag/Ce, Co/Ce, Mn/Ce, CeO, MnO) and evaluated in terms of activity, selectivity and stability. Mn/Ce shows the higher activity in 2 h with 97.7% reduction of total organic carbon (TOC) followed by: MnO(95.5%)>Ag/Ce(85.0%)>Co/Ce(65.1%)>CeO(61.2%). Attempts were also carried out to analyze the influence of different Mn/Ce molar ratios. High percentages of Mn lead to practically total organic carbon concentration (TOC) abatements while low ratios lead to the formation of non-oxidizable compounds. Acrylic acid was readily degraded by all the catalysts pointing out the high importance of using a catalytic process. pH was an indicator of the reaction pathway and acetic acid was found as the major reaction intermediate compound; however it is completely oxidized after 2 h with exception for Co/Ce, CeO and MnO. Carbon adsorption and leaching of metals were poorly found for Mn/Ce indicating high stability. The catalyst microstructure after the reaction was analyzed and formation of whiskers of β-MnO2 (or less probably MnOOH) were observed at the catalyst surface. Therefore, Mn/Ce revealed to be a promising catalyst for the treatment of effluents containing acrylic acid; nevertheless, its commercialization depends on further research. 相似文献
98.
Guimes Rodrigues Filho Leandra Cardoso Toledo Daniel Alves Cerqueira Rosana Maria Nascimento de Assunção Carla da Silva Meireles Harumi Otaguro Sizue Ota Rogero Ademar Benévolo Lugão 《Polymer Bulletin》2007,59(1):73-81
Summary In this article, cellulose acetate produced through the homogeneous acetylation of sugar cane bagasse cellulose was used to
produce membranes, using poly(ethyleneglycol) 600 (PEG 600) as an admixture. The membranes were characterized using water
flux measurements (Payne’s cup), differential scanning calorimetry (DSC) and neutral red uptake (cytotoxicity). The results
showed that PEG 600 acts as a crystallinity inductor and/or pore former in the cellulose acetate matrix. The induction of
crystallinity is important for this system since it had not been reported on the literature yet. The results also demonstrated
that the studied membranes present a nontoxic behavior. 相似文献
99.
Jean‐Rémy Falleri Xavier Blanc Reda Bendraou Marcos Aurélio Almeida da Silva Cédric Teyton 《Software》2014,44(5):621-641
Ensuring models’ consistency is a key concern when using a model‐based development approach. Therefore, model inconsistency detection has received significant attention over the last years. To be useful, inconsistency detection has to be sound, efficient, and scalable. Incremental detection is one way to achieve efficiency in the presence of large models. In most of the existing approaches, incrementalization is carried out at the expense of the memory consumption that becomes proportional to the model size and the number of consistency rules. In this paper, we propose a new incremental inconsistency detection approach that only consumes a small and model size‐independent amount of memory. It will therefore scale better to projects using large models and many consistency rules. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
100.
Talita da Cunha Mattos Flávia Maria Santoro Kate Revoredo Vanessa Tavares Nunes 《Computers in Industry》2014
A business process is a set of activities performed in a coordinated manner within an organizational and technical environment that is aimed toward a business goal. The flexibility of a process is related to an understanding of the unexpected events that occur when people, systems and resources interact and require adjustments. Thus, business processes must be designed to respond to information about different events and their specificity. This information defines what the literature calls “context”. To broaden the perception of context in the case of a business process, this work proposes an approach to characterize the context of a business process activity in a given domain through conceptual models structured in layers. A case study was conducted to evaluate the proposal, which provided evidence of the applicability of the model. 相似文献