78 research outputs found
Nanopatterned Self-Assembled Monolayers by Using Diblock Copolymer Micelles as Nanometer-Scale Adsorption and Etch Masks
Nanopatterned self-assembled monolayers (SAMs) are obtained from a simple, straight-forward procedure by using masks derived from monolayers of block copolymer micelles. The nanopatterned SAMs consist of regularly spaced circular hydrophilic areas with diams. of approx. 60 nm on a continuous hydrophopic background or vice versa. The surfaces are shown to be excellent tools for the prepn. of arrays of nanocrystal
Sex dependency of inhibitory control functions
BACKGROUND: Inhibition of irrelevant responses is an important aspect of cognitive control of a goal-directed behavior. Females and males show different levels of susceptibility to neuropsychological disorders such as impulsive behavior and addiction, which might be related to differences in inhibitory brain functions. METHODS: We examined the effects of ‘practice to inhibit’, as a model of rehabilitation approach, and ‘music’, as a salient contextual factor in influencing cognition, on the ability of females and males to perform a stop-signal task that required inhibition of initiated or planned responses. In go trials, the participants had to rapidly respond to a directional go cue within a limited time window. In stop trials, which were presented less frequently, a stop signal appeared immediately after the go-direction cue and the participants had to stop their responses. RESULTS: We found a significant difference between females and males in benefiting from practice in the stop-signal task: the percentage of correct responses in the go trials increased, and the ability to inhibit responses significantly improved, after practice in females. While listening to music, females became faster but males became slower in responding to the go trials. Both females and males became slower in performing the go trials following an error in the stop trials; however, music significantly affected this post-error slowing depending on the sex. Listening to music decreased post-error slowing in females but had an opposite effect in males. CONCLUSIONC: Here, we show a significant difference in executive control functions and their modulation by contextual factors between females and males that might have implications for the differences in their propensity for particular neuropsychological disorders and related rehabilitation approaches
MexEF-OprN Efflux Pump Exports the Pseudomonas Quinolone Signal (PQS) Precursor HHQ (4-hydroxy-2-heptylquinoline)
Bacterial cells have evolved the capacity to communicate between each other via small diffusible chemical signals termed autoinducers. Pseudomonas aeruginosa is an opportunistic pathogen involved, among others, in cystic fibrosis complications. Virulence of P. aeruginosa relies on its ability to produce a number of autoinducers, including 4-hydroxy-2-alkylquinolines (HAQ). In a cell density-dependent manner, accumulated signals induce the expression of multiple targets, especially virulence factors. This phenomenon, called quorum sensing, promotes bacterial capacity to cause disease. Furthermore, P. aeruginosa possesses many multidrug efflux pumps conferring adaptive resistance to antibiotics. Activity of some of these efflux pumps also influences quorum sensing. The present study demonstrates that the MexEF-OprN efflux pump modulates quorum sensing through secretion of a signalling molecule belonging to the HAQ family. Moreover, activation of MexEF-OprN reduces virulence factor expression and swarming motility. Since MexEF-OprN can be activated in infected hosts even in the absence of antibiotic selective pressure, it could promote establishment of chronic infections in the lungs of people suffering from cystic fibrosis, thus diminishing the immune response to virulence factors. Therapeutic drugs that affect multidrug efflux pumps and HAQ-mediated quorum sensing would be valuable tools to shut down bacterial virulence
Development of an ex vivo porcine lung model for studying growth, virulence, and signaling of Pseudomonas aeruginosa
Research into chronic infection by bacterial pathogens, such as Pseudomonas aeruginosa, uses various in vitro and live host models. While these have increased our understanding of pathogen growth, virulence, and evolution, each model has certain limitations. In vitro models cannot recapitulate the complex spatial structure of host organs, while experiments on live hosts are limited in terms of sample size and infection duration for ethical reasons; live mammal models also require specialized facilities which are costly to run. To address this, we have developed an ex vivo pig lung (EVPL) model for quantifying Pseudomonas aeruginosa growth, quorum sensing (QS), virulence factor production, and tissue damage in an environment that mimics a chronically infected cystic fibrosis (CF) lung. In a first test of our model, we show that lasR mutants, which do not respond to 3-oxo-C12-homoserine lactone (HSL)-mediated QS, exhibit reduced virulence factor production in EVPL. We also show that lasR mutants grow as well as or better than a corresponding wild-type strain in EVPL. lasR mutants frequently and repeatedly arise during chronic CF lung infection, but the evolutionary forces governing their appearance and spread are not clear. Our data are not consistent with the hypothesis that lasR mutants act as social “cheats” in the lung; rather, our results support the hypothesis that lasR mutants are more adapted to the lung environment. More generally, this model will facilitate improved studies of mi- crobial disease, especially studies of how cells of the same and different species interact in polymicrobial infections in a spatially structured environment
Use of Opuntia ficus-indica (L.) Mill extracts from Brazilian Caatinga as an alternative of natural moisturizer in cosmetic formulations
ABSTRACT The aim of this work was the obtainment of Opuntia fícus-indica (L.) Mill extract for the development of cosmetic formulations and in vivo evaluation of its moisturizing effects. The formulations were tested for preliminary and accelerated stability. Organoleptic characteristics, pH values and rheological behavior were assessed. The evaluation of moisturizing efficacy of the emulsions formulated with 3.0% of Polyacrylamide (and) C13-14 Isoparaffin (and) Laureth-7 containing 1.0 and 3.0% of O. ficus-indica hydroglycolic extract (EHG001) was performed using the capacitance method (Corneometer(r)) and the transepidermal water loss - TEWL evaluation (Tewameter(r)). The emulsions formulated were stable, exhibiting pseudoplastic and thixotropic behavior. The results of evaluation of moisturizing efficacy showed increased skin hydration after five hours by mainly increasing the skin barrier effect. The formulations containing 1.0 and 3.0% of EHG001 enhanced the skin barrier effect by reducing TEWL up to four hours after application. The results observed suggest that O. ficus-indica hydroglycolic extract may act through a humectant and occlusion mechanism
Single cell RNAseq-based proteogenomics identifies glioblastoma-specific transposable elements encoding HLA-presented peptides
We developed a transposable element (TE)-centered proteogenomic pipeline that combines single cell transcriptomics on tumors from glioblastoma (GBM) patients, bulk RNAseq samples from tumor and healthy tissue cohorts, and immunopeptidomics. We thus identified 370 HLA-I-bound peptides encoded by TEs differentially expressed in GBM. Some of the peptides are encoded by repeat sequences from intact open reading frames (ORFs) present in up to several hundred TEs from recent LINE-1, LTR and SVA subfamilies. Other HLA-I-bound peptides are encoded by unique copies of TEs from old subfamilies that are expressed recurrently in GBM tumors and not expressed, or very infrequently and at low levels, in healthy tissues (including brain). These peptide-coding, GBM-specific, highly recurrent TEs represent potential tumor-specific targets for cancer immunotherapies.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
Ferromanganese deposits in cores from the Kane and Atlantis fracture areas: possible relationships with hydrothermalism
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Using in-situ radionuclides to model sediment transfer at the flow event time scale
International audienceSediment flow modeling over geological time scales requires a good understanding of the sediment transport modes occurring in rivers. Mean sediment residence time within hydraulic networks in response to flow events needs to be determined. In this background, the fallout natural environment radionuclide beryllium-7 (Be, half-life of 53.3 days) and the in-situ artificial radionuclide iodine-131 ( I, half-life of 8.05 days) provide reliable tools to better understand the sediment transfer at the flow event time scale. Our model is based on the radioactive decay of the Be and I associated with suspended sediments. The short half-lives of Be and I allow phenomena to be studied at the flow event time scale. In this context radionuclide inputs have to be well-identified. The artificial iodine I source is well-defined as this radionuclide most likely originates from hospitals where it is used in radiotherapy. In the case of Be, the possibility that cities are radionuclide traps as they may provide high radionuclide concentration to channels, at time t, compared with bank inputs, is discussed. Natural environment radionuclide potentiality to estimate mean sediment residence time in a river section is demonstrated from in-situ data
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