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1.
Ann Surg Oncol ; 30(8): 5036-5046, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37069476

RESUMO

BACKGROUND: It is unclear whether preoperative biliary drainage (PBD) by endoscopic retrograde cholangiopancreatography (ERCP) is equivalent to electrocautery-enhanced lumen-apposing metal stent (ECE-LAMS) before pancreatoduodenectomy (PD). METHODS: Patients who underwent PBD for distal malignant biliary obstruction (DMBO) followed by PD were retrospectively included in nine expert centers between 2015 and 2022. ERCP or endoscopic ultrasound-guided choledochoduodenostomy with ECE-LAMS were performed. In intent-to-treat analysis, patients drained with ECE-LAMS were considered the study group (first-LAMS group) and those drained with conventional transpapillary stent the control group (first-cannulation group). The rates of technical success, clinical success, drainage-related complications, surgical complications, and oncological outcomes were analyzed. RESULTS: Among 156 patients, 128 underwent ERCP and 28 ECE-LAMS in first intent. The technical and clinical success rates were 83.5% and 70.2% in the first-cannulation group versus 100% and 89.3% in the first-LAMS group (p = 0.02 and p = 0.05, respectively). The overall complication rate over the entire patient journey was 93.7% in first-cannulation group versus 92.0% in first-LAMS group (p = 0.04). The overall endoscopic complication rate was 30.5% in first-cannulation group versus 17.9% in first-LAMS group (p = 0.25). The overall complication rate after PD was higher in the first-cannulation group than in the first-LAMS group (92.2% versus 75.0%, p = 0.016). Overall survival and progression-free survival did not differ between the groups. CONCLUSIONS: PBD with ECE-LAMS is easier to deploy and more efficient than ERCP in patients with DMBO. It is associated with less surgical complications after pancreatoduodenectomy without compromising the oncological outcome.


Assuntos
Coledocostomia , Colestase , Humanos , Coledocostomia/efeitos adversos , Pancreaticoduodenectomia/efeitos adversos , Estudos de Coortes , Estudos Retrospectivos , Colestase/etiologia , Colestase/cirurgia , Stents/efeitos adversos , Endossonografia , Colangiopancreatografia Retrógrada Endoscópica/efeitos adversos , Drenagem/efeitos adversos , Ultrassonografia de Intervenção
2.
Food Microbiol ; 112: 104217, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36906300

RESUMO

Brettanomyces bruxellensis is the most damaging spoilage yeast in the wine industry because of its negative impact on the wine organoleptic qualities. The strain persistence in cellars over several years associated with recurrent wine contamination suggest specific properties to persist and survive in the environment through bioadhesion phenomena. In this work, the physico-chemical surface properties, morphology and ability to adhere to stainless steel were studied both on synthetic medium and on wine. More than 50 strains representative of the genetic diversity of the species were considered. Microscopy techniques made it possible to highlight a high morphological diversity of the cells with the presence of pseudohyphae forms for some genetic groups. Analysis of the physico-chemical properties of the cell surface reveals contrasting behaviors: most of the strains display a negative surface charge and hydrophilic behavior while the Beer 1 genetic group has a hydrophobic behavior. All strains showed bioadhesion abilities on stainless steel after only 3 h with differences in the concentration of bioadhered cells ranging from 2.2 × 102 cell/cm2 to 7.6 × 106 cell/cm2. Finally, our results show high variability of the bioadhesion properties, the first step in the biofilm formation, according to the genetic group with the most marked bioadhesion capacity for the beer group.


Assuntos
Brettanomyces , Vinho , Microbiologia de Alimentos , Aço Inoxidável/análise , Brettanomyces/metabolismo , Vinho/análise , Saccharomyces cerevisiae
3.
Int J Mol Sci ; 23(1)2021 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-35008757

RESUMO

The recruitment of pericytes and vascular smooth muscle cells (SMCs) that enwrap endothelial cells (ECs) is a crucial process for vascular maturation and stabilization. Communication between these two cell types is crucial during vascular development and in maintaining vessel homeostasis. Extracellular vesicles (EVs) have emerged as a new communication tool involving the exchange of microRNAs between cells. In the present study, we searched for microRNAs that could be transferred via EVs from ECs to SMCs and vice versa. Thanks to a microRNA profiling experiment, we found that two microRNAs are more exported in each cell type in coculture experiments: while miR-539 is more secreted by ECs, miR-582 is more present in EVs from SMCs. Functional assays revealed that both microRNAs can modulate both cell-type phenotypes. We further identified miR-539 and miR-582 targets, in agreement with their respective cell functions. The results obtained in vivo in the neovascularization model suggest that miR-539 and miR-582 might cooperate to trigger the process of blood vessel coverage by smooth muscle cells in a mature plexus. Taken together, these results are the first to highlight the role of miR-539 and miR-582 in angiogenesis and communication between ECs and SMCs.


Assuntos
Comunicação Celular , Vesículas Extracelulares/metabolismo , Células Endoteliais da Veia Umbilical Humana/citologia , Músculo Liso Vascular/citologia , Miócitos de Músculo Liso/citologia , Vasos Sanguíneos/metabolismo , Técnicas de Cocultura , Vesículas Extracelulares/ultraestrutura , Regulação da Expressão Gênica , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Modelos Biológicos , Neovascularização Fisiológica/genética , Remodelação Vascular
4.
Microbiology (Reading) ; 166(3): 239-252, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31935186

RESUMO

In the marine environment, most solid surfaces are covered by microbial biofilms, mainly composed of bacteria and diatoms. The negative effects of biofilms on materials and equipment are numerous and pose a major problem for industry and human activities. Since marine micro-organisms are an important source of bioactive metabolites, it is possible that they synthesize natural ecofriendly molecules that inhibit the adhesion of organisms. In this work, the antibiofilm potential of marine bacteria was investigated using Flavobacterium sp. II2003 as a target. This strain is potentially a pioneer strain of bacteria that was previously selected from marine biofilms for its strong biofilm-forming ability. The culture supernatants of 86 marine heterotrophic bacteria were tested for their ability to inhibit Flavobacterium sp. II2003 biofilm formation and the Pseudomonas sp. IV2006 strain was identified as producing a strong antibiofilm activity. The Pseudomonas sp. IV2006 culture supernatant (SNIV2006) inhibited Flavobacterium sp. II2003 adhesion without killing the bacteria or inhibiting its growth. Moreover, SNIV2006 had no effect on the Flavobacterium sp. II2003 cell surface hydrophilic/hydrophobic and general Lewis acid-base characteristics, but modified the surface properties of glass, making it on the whole more hydrophilic and more alkaline and significantly reducing bacterial cell adhesion. The glass-coating molecules produced by Pseudomonas sp. IV2006 were found to probably be polysaccharides, whereas the antibiofilm molecules contained in SNIV2006 and acting during the 2 h adhesion step on glass and polystyrene surfaces would be proteinaceous. Finally, SNIV2006 exhibited a broad spectrum of antibiofilm activity on other marine bacteria such as Flavobacterium species that are pathogenic for fish, and human pathogens in both the medical environment, such as Staphylococcus aureus and Pseudomonas aeruginosa, and in the food industry, such as Yersinia enterocolitica. Thus, a wide range of applications could be envisaged for the SNIV2006 compounds, both in aquaculture and human health.


Assuntos
Antibacterianos , Flavobacterium/efeitos dos fármacos , Pseudomonas/metabolismo , Animais , Antibacterianos/biossíntese , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Organismos Aquáticos/metabolismo , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Peixes/microbiologia , Flavobacterium/crescimento & desenvolvimento , Humanos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Yersinia enterocolitica/efeitos dos fármacos , Yersinia enterocolitica/crescimento & desenvolvimento
5.
Nat Mater ; 18(7): 752-759, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31160804

RESUMO

Hydrogen production from water electrolysis is a key enabling energy storage technology for the large-scale deployment of intermittent renewable energy sources. Proton ceramic electrolysers (PCEs) can produce dry pressurized hydrogen directly from steam, avoiding major parts of cost-driving downstream separation and compression. However, the development of PCEs has suffered from limited electrical efficiency due to electronic leakage and poor electrode kinetics. Here, we present the first fully operational BaZrO3-based tubular PCE, with 10 cm2 active area and a hydrogen production rate above 15 Nml min-1. The novel steam anode Ba1-xGd0.8La0.2+xCo2O6-δ exhibits mixed p-type electronic and protonic conduction and low activation energy for water splitting, enabling total polarization resistances below 1 Ω cm2 at 600 °C and Faradaic efficiencies close to 100% at high steam pressures. These tubular PCEs are mechanically robust, tolerate high pressures, allow improved process integration and offer scale-up modularity.

6.
Appl Environ Microbiol ; 84(24)2018 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-30291116

RESUMO

Lavender decline compromises French lavender production, and preliminary data have suggested the involvement of "Candidatus Phytoplasma solani" in the etiology of the disease. In order to evaluate the epidemiological role of "Ca Phytoplasma solani," a 3-year survey was conducted in southeastern France. "Ca Phytoplasma solani" was detected in 19 to 56% of the declining plants, depending on seasons and cultivars, and its prevalence was correlated with symptom severity. Autumn was more favorable than spring for phytoplasma detection, and "Ca Phytoplasma solani" incidence was higher in Lavandula angustifolia than in Lavandula intermedia hybrids. Detection of the phytoplasma fluctuated over months, supporting the chronicity of infection. Three "Ca Phytoplasma solani" secY genotypes, S17, S16, and S14, were the most prevalent in lavender fields and were also detected in nurseries, whereas strains detected in surrounding bindweed and wild carrots were mostly of the S1 and S4 genotypes. This suggests that lavender is the main pathogen reservoir of the epidemic. Adults and nymphs of the planthopper vector Hyalesthes obsoletus were commonly captured in lavender fields and were shown to harbor mainly the prevalent phytoplasma genotypes detected in lavenders. The "Ca Phytoplasma solani" genotype S17 was transmitted to Catharanthus roseus periwinkle by naturally infected H. obsoletus Finally, the inventory of the bacterial community of declining lavenders that tested negative for "Ca Phytoplasma solani" by 16S rRNA deep sequencing ruled out the involvement of other phloem-limited bacterial pathogens.IMPORTANCE The etiology and main pathways for the spread of lavender decline, an infectious disease affecting French lavender production since the 1960s, have remained unclear, hampering the development of efficient control strategies. An extensive survey of lavender fields led to the conclusion that "Candidatus Phytoplasma solani" was chronically infecting declining lavenders and was associated with large infectious populations of Hyalesthes obsoletus planthoppers living on the crop itself. Lavender appeared to be the main reservoir host for lavender-specific phytoplasma strains, an unusual feature for this phytoplasma, which usually propagates from reservoir weeds to various economically important crops. These results point out the necessity to protect young lavender fields from the initial phytoplasma inoculum coming from surrounding lavender fields or from infected nurseries and to promote agricultural practices that reduce the development of H. obsoletus vector populations.


Assuntos
Lavandula/microbiologia , Phytoplasma/classificação , Phytoplasma/patogenicidade , Doenças das Plantas/microbiologia , Animais , França , Genótipo , Técnicas de Genotipagem , Hemípteros/microbiologia , Epidemiologia Molecular , Filogenia , Phytoplasma/genética , Phytoplasma/isolamento & purificação , Prevalência , RNA Ribossômico 16S/genética , Vinca/microbiologia
8.
Faraday Discuss ; 192: 251-269, 2016 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-27478073

RESUMO

Dual phase membranes are highly CO2-selective membranes with an operating temperature above 400 °C. The focus of this work is to quantify the potential of dual phase membranes in pre- and post-combustion CO2 capture processes. The process evaluations show that the dual phase membranes integrated with an NGCC power plant for CO2 capture are not competitive with the MEA process for post-combustion capture. However, dual phase membrane concepts outperform the reference Selexol technology for pre-combustion CO2 capture in an IGCC process. The two processes evaluated in this work, post-combustion NGCC and pre-combustion IGCC, represent extremes in CO2 partial pressure fed to the separation unit. Based on the evaluations it is expected that dual phase membranes could be competitive for post-combustion capture from a pulverized coal fired power plant (PCC) and pre-combustion capture from an Integrated Reforming Cycle (IRCC).

9.
Langmuir ; 28(49): 17001-10, 2012 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-23157649

RESUMO

The interaction of hydrophilic and hydrophobic ovococcoid bacteria and bovine serum albumin (BSA) proteins with a well ordered surface of octadecanethiol (ODT) self assembled monolayer (SAM) has been studied in different situations where proteins were either preadsorbed on ODT or adsorbed simultaneously with bacterial adhesion as in life conditions. The two situations lead to very different antimicrobial behavior. Bacterial adhesion on preadsorbed BSA is very limited, while the simultaneous exposure of ODT SAM to proteins and bacteria lead to a markedly weaker antimicrobial effect. The combination of sum frequency generation spectroscopy and fluorescence confocal microscopy experiments allow one to draw conclusions on the factors that govern the ODT SAM or BSA film interaction with bacteria at the molecular level. On the hydrophobic ODT surface, interaction with hydrophobic or hydrophilic biomolecules results in opposite effects on the SAM, namely, a flattening or a raise of the terminal methyl groups of ODT. On an amphiphilic BSA layer, the bacterial adhesion strength is weakened by the negative charges carried by both BSA and bacteria. Surprisingly, preadsorbed BSA that cover part of the bacteria cell walls increase the adhesion strength to the BSA film and reduce hydrophobic interactions with the ODT SAM. Finally, bacterial adhesion on a BSA film is shown to modify the BSA proteins in some way that change their interaction with the ODT SAM. The antimicrobial effect is much stronger in the case of a preadsorbed BSA layer than when BSA and bacteria are in competition to colonize the ODT SAM surface.


Assuntos
Alcanos/química , Aderência Bacteriana , Lactococcus lactis/química , Soroalbumina Bovina/química , Compostos de Sulfidrila/química , Adsorção , Ligação Competitiva , Interações Hidrofóbicas e Hidrofílicas , Microscopia Confocal , Microscopia de Fluorescência , Análise Espectral/métodos , Eletricidade Estática , Propriedades de Superfície , Termodinâmica , Vibração
10.
Soins Psychiatr ; (278): 37-40, 2012.
Artigo em Francês | MEDLINE | ID: mdl-22423451

RESUMO

Therapeutic gîtes in child psychiatry. A therapeutic stay in a gîte is a project led by a multidisciplinary team. It enables children to experiment with the notion of pleasure and to develop their level of socialisation, their personality and their independence, outside the family environment. For caregivers, it provides a rich source of clinical material and strengthens the team dynamics.


Assuntos
Transtornos do Comportamento Infantil/enfermagem , Comportamento Cooperativo , Comunicação Interdisciplinar , Desenvolvimento da Personalidade , Enfermagem Psiquiátrica , Socialização , Comunidade Terapêutica , Adaptação Psicológica , Criança , Transtornos do Comportamento Infantil/psicologia , Pré-Escolar , Feminino , França , Humanos , Individuação , Masculino , Relações Enfermeiro-Paciente , Avaliação em Enfermagem , Relações Profissional-Família , Carência Psicossocial , Meio Social
11.
J Proteomics ; 250: 104388, 2022 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-34601155

RESUMO

Listeria monocytogenes presents a dimorphism associated to the SecA2 activity with cells having a normal rod shape or a dysmorphic elongated filamentous form. Besides variation of the cell and colony morphotype, this cell differentiation has profound ecophysiological and physiopathological implications with collateral effects on virulence and pathogenicity, biotope colonisation, bacterial adhesion and biofilm formation. This suggests the SecA2-only protein export could influence the listerial cell surface, which was investigated first by characterising its properties in L. monocytogenes wt and ΔsecA2. The degree of hydrophilicity and Lewis acid-base properties appeared significantly affected upon SecA2 inactivation. As modification of electrostatic properties would owe to modification in the composition of cell-surface proteins, the proteosurfaceome was further investigated by shotgun label-free proteomic analysis with a comparative relative quantitative approach. Following secretomic analysis, the protein secretion routes of the identified proteins were mapped considering the cognate transport and post-translocational maturation systems, as well as protein categories and subcellular localisation. Differential protein abundance profiles coupled to network analysis revealed the SecA2 dependence of 48 proteins, including some related to cell envelope biogenesis, translation and protein export, which could account for modifications of adhesion and surface properties of L. monocytogenes upon SecA2 inactivation. This investigation unravelled the profound influence of SecA2 activity on the cell surface properties and proteosurfaceome of L. monocytogenes, which provides advanced insights about its ecophysiopathology. SIGNIFICANCE: L. monocytogenes is a foodborne zoonotic pathogen and etiological agent of human listeriosis. This species presents a cellular dimorphism associated to the SecA2 activity that has profound physiopathological and ecophysiological implications with collateral effects on bacterial virulence and colonisation. To explore the influence of the SecA2-only protein export on the listerial cell, the surface properties of L. monocytogenes expressing or depleted of SecA2 was characterised by microelectrophoresis, microbial affinity to solvents and contact angles analyses. As modifications of hydrophilicity and Lewis acid-base electrostatic properties would owe to modification in the composition of cell-surface proteins, the proteinaceous subset of the surfaceome, i.e. the proteosurfaceome, was investigated further by shotgun label-free proteomic analysis. This subproteome appeared quite impacted upon SecA2 inactivation with the identification of proteins accounting for modifications in the cell surface properties. The profound influence of SecA2 activity on the cell surface of L. monocytogenes was unravelled, which provides advanced insights about its ecophysiopathology.


Assuntos
Listeria monocytogenes , Adenosina Trifosfatases , Proteínas de Bactérias/metabolismo , Humanos , Listeria monocytogenes/metabolismo , Proteínas de Membrana Transportadoras/fisiologia , Proteômica
12.
Appl Environ Microbiol ; 77(1): 367-8, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21037304

RESUMO

Diffusion of entities inside biofilm triggers most mechanisms involved in biofilm-specific phenotypes. Using genetically engineered hydrophilic and hydrophobic cells of Lactococcus lactis yielding similar biofilm architectures, we demonstrated by fluorescence correlation spectroscopy that bacterial surface properties affect diffusion of nanoparticles through the biofilm matrix.


Assuntos
Biofilmes , Parede Celular/química , Difusão , Interações Hidrofóbicas e Hidrofílicas , Lactococcus lactis/química , Lactococcus lactis/genética , Nanopartículas/química
13.
Langmuir ; 27(8): 4928-35, 2011 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-21410205

RESUMO

Understanding bacterial adhesion on a surface is a crucial step to design new materials with improved properties or to control biofilm formation and eradication. Sum Frequency Generation (SFG) vibrational spectroscopy has been employed to study in situ the conformational response of a self-assembled monolayer (SAM) of octadecanethiol (ODT) on a gold film to the adhesion of hydrophilic and hydrophobic ovococcoid model bacteria. The present work highlights vibrational SFG spectroscopy as a powerful and unique non-invasive biophysical technique to probe and control bacteria interaction with ordered surfaces. Indeed, the SFG vibrational spectral changes reveal different ODT SAM conformations in air and upon exposure to aqueous solution or bacterial adhesion. Furthermore, this effect depends on the bacterial cell surface properties. The SFG spectral modeling demonstrates that hydrophobic bacteria flatten the ODT SAM alkyl chain terminal part, whereas the hydrophilic ones raise this ODT SAM terminal part. Microorganism-induced alteration of grafted chains can thus affect the desired interfacial functionality, a result that should be considered for the design of new reactive materials.


Assuntos
Alcanos/química , Aderência Bacteriana/efeitos dos fármacos , Compostos de Sulfidrila/química , Interações Hidrofóbicas e Hidrofílicas , Conformação Molecular , Espectrofotometria Infravermelho
14.
Appl Environ Microbiol ; 76(22): 7662-4, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20889799

RESUMO

Electrical discharges in humid air at atmospheric pressure (nonthermal quenched plasma) generate long-lived chemical species in water that are efficient for microbial decontamination. The major role of nitrites was evidenced together with a synergistic effect of nitrates and H(2)O(2) and matching acidification. Other possible active compounds are considered, e.g., peroxynitrous acid.


Assuntos
Desinfetantes/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Água/química , Água/farmacologia , Eletricidade , Peróxido de Hidrogênio/farmacologia , Nitratos/farmacologia , Nitritos/farmacologia
15.
J Neurol ; 267(10): 2829-2841, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32447550

RESUMO

INTRODUCTION: Whether different mechanisms, particularly ocular pathology, could lead to the emergence of visual hallucinations (VH) (defined as false perceptions with no external stimulus) versus visual illusions (VI) (defined as a misperception of a real stimulus) in Parkinson's disease (PD) remains debated. We assessed retinal, clinical and structural brain characteristics depending on the presence of VH or VI in PD. METHODS: In this case-control study, we compared retinal thickness using optical coherence tomography (OCT), between PD patients with: VI (PD-I; n = 26), VH (PD-H; n = 28), and without VI or VH (PD-C; n = 28), and assessed demographic data, disease severity, treatment, anatomical and functional visual complaints, cognitive and visuo-perceptive functions and MRI brain volumetry for each group of PD patients. RESULTS: Parafoveal retina was thinner in PD-H compared to PD-C (p = 0.005) and PD-I (p = 0.009) but did not differ between PD-I and PD-C (p = 0.85). Multivariate analysis showed that 1/retinal parafoveal thinning and total brain gray matter atrophy were independently associated with the presence of VH compared to PD-I; 2/retinal parafoveal thickness, PD duration, sleep quality impairment and total brain gray matter volume were independent factors associated with the presence of VH compared to PD-C; 3/anterior ocular abnormalities were the only factor independently associated with the presence of illusions compared to PD-C. CONCLUSION: These findings reinforce the hypothesis that there may be different mechanisms contributing to VH and VI in PD, suggesting that these two entities may also have a different prognosis rather than simply lying along a continuous spectrum. REGISTRATION NUMBER: Clinicaltrials.gov number NCT01114321.


Assuntos
Alucinações , Ilusões , Doença de Parkinson , Atrofia , Estudos de Casos e Controles , Substância Cinzenta/patologia , Alucinações/etiologia , Humanos , Ilusões/etiologia , Doença de Parkinson/complicações , Doença de Parkinson/diagnóstico por imagem
16.
Macromol Biosci ; 20(10): e2000157, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32734716

RESUMO

Polyionenes (PI) with stable positive charges and tunable hydrophobic spacers in the polymer backbone, are shown to be particularly efficient regarding antimicrobial properties. This effect can be modulated since it increases with the length of hydrophobic spacers, i.e., the number of methylene groups between quaternary ammoniums. Now, to further explore these properties and provide efficient antimicrobial surfaces, polyionenes should be grafted onto materials. Here a robust grafting strategy to covalently attach polyionenes is described. The method consisted in a sequential surface chemistry procedure combining polydopamine coating, diazonium-induced polymerization, and polyaddition. To the best of knowledge, grafting of PI onto surfaces is not reported earlier. All chemical steps are characterized in detail via various surface analysis techniques (FTIR, X-ray photoelectron spectroscopy, contact angle, and surface energy measurements). The antibacterial properties of polyionene-grafted surfaces are then studied through bacterial adhesion experiments consisting in enumeration of adherent bacteria (total and viable cultivable cells). PI-grafted surfaces are showed to display effective and versatile bacteriostatic/bactericidal properties associated with a proadhesive effect.


Assuntos
Anti-Infecciosos/farmacologia , Polímeros/química , Aderência Bacteriana/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Peso Molecular , Espectroscopia Fotoeletrônica , Polimerização , Pele/citologia , Pele/efeitos dos fármacos , Soluções , Staphylococcus aureus/efeitos dos fármacos , Propriedades de Superfície
17.
Acta Crystallogr C ; 65(Pt 4): i11-3, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19346592

RESUMO

Lanthanum nickel niobium trioxide has been synthesized and its structure refined for the first time. It was found to be a member of the family of technologically important ;double perovskites', crystallizing in the monoclinic space group P2(1)/n. The structure is characterized by a strong orthorhombic pseudosymmetry and a concurrent exhibition of both 1:1 B-cation ordering and a(-)a(-)c(+)-type tilting of the (Ni/Nb)O(6) structural units. Trivalent lanthanum resides on the perovskite A site, which is strongly distorted owing to the tilting of the (Ni/Nb)O(6) sublattice. Ordering of divalent nickel and pentavalent niobium on the B sublattice is described in terms of two twofold special positions (2c and 2d), with nickel taking almost complete occupancy of the 2d site and the 2c position being occupied by a statistical distribution of nickel and niobium.

18.
Materials (Basel) ; 12(20)2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31640202

RESUMO

Compositionally engineered a La1-xBaxCoO3-δ-(1-a) BaZr0.9Y0.1O2.95 (a = 0.6, 0.7, 0.8 and x = 0.5, 0.6, 0.7) (LBZ) nanocomposite cathodes were prepared by oxidation driven in situ exsolution of a single-phase material deposited on a BaZr0.9Y0.1O2.95 electrolyte. The processing procedure of the cathode was optimized by reducing the number of thermal treatments as the single-phase precursor was deposited directly on the electrolyte. The exsolution and firing of the cathodes occurred in one step. The electrochemical performance of symmetrical cells with the compositionally engineered cathodes was investigated by impedance spectroscopy in controlled atmospheres. The optimized materials processing gave web-like nanostructured cathodes with superior electrochemical performance for all compositions. The area specific resistances obtained were all below 12 Ω·cm2 at 400 °C and below 0.59 Ω·cm2 at 600 °C in 3% moist synthetic air. The resistances of the nominal 0.6 La0.5Ba0.5CoO3-δ-0.4 BaZr0.9Y0.1O2.95 and 0.8 La0.5Ba0.5CoO3-δ-0.2 BaZr0.9Y0.1O2.95 composite cathodes were among the lowest reported for protonic ceramic fuel cells cathodes in symmetrical cell configuration with ASR equal to 4.04 and 4.84 Ω·cm2 at 400 °C, and 0.21 and 0.27 Ω·cm2 at 600 °C, respectively.

19.
Membranes (Basel) ; 9(10)2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31554293

RESUMO

Asymmetric tubular ceramic-ceramic (cercer) membranes based on La27W3.5Mo1.5O55.5-δ-La0.87Sr0.13CrO3-δ were fabricated by a two-step firing method making use of water-based extrusion and dip-coating. The performance of the membranes was characterized by measuring the hydrogen permeation flux and water splitting with dry and wet sweep gases, respectively. To explore the limiting factors for hydrogen and oxygen transport in the asymmetric membrane architecture, the effect of different gas flows and switching the feed and sweep sides of the membrane on the apparent hydrogen permeability was investigated. A dusty gas model was used to simulate the gas gradient inside the porous support, which was combined with Wagner diffusion calculations of the dense membrane layer to assess the overall transport across the asymmetric membrane. In addition, the stability of the membrane was investigated by means of flux measurements over a period of 400 h.

20.
Appl Microbiol Biotechnol ; 81(3): 449-57, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18769918

RESUMO

This paper describes the effects of initial microbial concentration and planktonic/adherent/detached states on the efficiency of plasma-activated water. This disinfecting solution was obtained by treating distilled water with an atmospheric pressure plasma produced by gliding electric discharges in humid air. The inactivation kinetics of planktonic cells of Hafnia alvei (selected as a bacterial model) were found to be of the first order. They were influenced by the initial microbial concentration. Efficiency decreased when the initial viable population N(0) increased, and the inactivation rate k(max) was linearly modified as a function of Log(10) (N(0)). This relation was used to compare planktonic, adherent, and detached cells independently from the level of population. Bacteria adhering to stainless steel and high-density polyethylene were also sensitive to treatment, but at a lower rate than their free-living counterparts. Moreover, cells detached from these solid substrates exhibited an inactivation rate lower than that of planktonic cells but similar to adherent bacteria. This strongly suggests the induction of a physiological modification to bacteria during the adhesion step, rendering adherent--and further detached--bacteria less susceptible to the treatment, when compared to planktonic bacteria.


Assuntos
Aderência Bacteriana/efeitos dos fármacos , Desinfetantes/farmacologia , Desinfecção/métodos , Hafnia alvei/efeitos dos fármacos , Água/farmacologia , Desinfetantes/química , Hafnia alvei/fisiologia , Temperatura Alta , Cinética , Pressão de Vapor , Água/química
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