1,300 research outputs found

    Properties of Styrene–Maleic Anhydride Copolymer Compatibilized Polyamide 66/Poly (Phenylene Ether) Blends : Effect of Maleic Anhydride Concentration and Copolymer Content

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    Polyamide 66 (PA66)/poly (2,6-dimethyl-1,4-phenylene ether) (PPE) blends with a ratio of 50/50 (w/w) were produced by a twin-screw compounder. The immiscible blends were compatibilized using two different styrene–maleic anhydride copolymers (SMA) with a low (SMAlow) and a high (SMAhigh) maleic anhydride (MA) concentration of 8 and 25 wt%, respectively. Furthermore, the SMA content was varied from 0 to 10 wt%. The influence of MA concentration and SMA content on the morphological and thermomechanical properties of PA66/PPE blends was investigated. Herein, we established correlations between the interfacial activity of the SMA with blend morphology and corresponding tensile properties. A droplet-sea to co-continuous morphology transition was shown by scanning electron microscopy to occur between 1.25 and 5 wt% in the case of SMAhigh. For SMAlow, the transition started from 7.5 wt% and was still ongoing at 10 wt%. It was found that SMAlow with 10 wt% content enhanced the tensile strength (10%) and elongation at break (70%) of PA66/PPE blends. This improvement can be explained by the strong interfacial interaction of SMAlow within the blend system, which features the formation of nanoemulsion morphology, as shown by transmission electron microscopy. Very small interdomain distances hinder matrix deformations, which forces debonding and cohesive failure of the PPE phase as a “weaker” main deformation mechanism. Due to a lack of interfacial activity, the mechanical properties of the blends with SMAhigh were not improved

    Cerrado and Pantanal fruit flours affect gut microbiota composition in healthy and post-COVID-19 individuals: An in vitro pilot fermentation study

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    Cerrado and Pantanal plants can provide fruits with high nutritional value and antioxidants. This study aims to evaluate four fruit flours (from jatobá pulp, cumbaru almond, bocaiuva pulp and bocaiuva almond) and their effects on the gut microbiota in healthy (HD) and post-COVID-19 individuals (PC). An in vitro batch system was carried out, the microbiota was analysed by 16S rRNA amplicon sequencing and the short-chain fatty acids (SCFAs) ratio was determined. Furthermore, the effect of jatobá pulp flour oil (JAO) on cell viability, oxidative stress and DNA damage was investigated in a myelomonocytic cell line. Beyond confirming a microbiota imbalance in PC, we identified flourspecific effects: i) reduction of Veillonellaceae with jatobá extract in PC samples;decrease in Akkermansia with jatoba and cumbaru flours; iii) decreasing trend of Faecalibacterium and Ruminococcus with all flours tested, with the exception of the bocaiuva almond in HD samples for Ruminococcus; and iv) increase in Lactobacillus and Bifidobacterium in PC samples with bocaiuva almond flour. JAO displayed antioxidant properties protecting cells from daunorubicin-induced cytotoxicity, oxidative stress, and DNA damage. The promising microbiota modulating abilities of some flours and the chemopreventive effects of JAO deserve to be further explored in human intervention studies

    Impact of Enzymatic Degradation on the Material Properties of Poly(Ethylene Terephthalate)

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    With macroscopic litter and its degradation into secondary microplastic as a major source of environmental pollution, one key challenge is understanding the pathways from macro- to microplastic by abiotic and biotic environmental impact. So far, little is known about the impact of biota on material properties. This study focuses on recycled, bottle-grade poly(ethylene terephthalate) (r-PET) and the degrading enzyme PETase from Ideonella sakaiensis. Compact tension (CT) specimens were incubated in an enzymatic solution and thermally and mechanically characterized. A time-dependent study up to 96 h revealed the formation of steadily growing colloidal structures. After 96 h incubation, high amounts of BHET dimer were found in a near-surface layer, affecting crack propagation and leading to faster material failure. The results of this pilot study show that enzymatic activity accelerates embrittlement and favors fragmentation. We conclude that PET-degrading enzymes must be viewed as a potentially relevant acceleration factor in macroplastic degradation

    Spitzer spectral line mapping of protostellar outflows: I. Basic data and outflow energetics

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    We report the results of spectroscopic mapping observations carried out toward protostellar outflows in the BHR71, L1157, L1448, NGC 2071, and VLA 1623 molecular regions using the Infrared Spectrograph (IRS) of the Spitzer Space Telescope. These observations, covering the 5.2 - 37 micron spectral region, provide detailed maps of the 8 lowest pure rotational lines of molecular hydrogen and of the [SI] 25.25 micron and [FeII] 26.0 micron fine structure lines. The molecular hydrogen lines, believed to account for a large fraction of the radiative cooling from warm molecular gas that has been heated by a non-dissociative shock, allow the energetics of the outflows to be elucidated. Within the regions mapped towards these 5 outflow sources, total H2 luminosities ranging from 0.02 to 0.75 L(solar) were inferred for the sum of the 8 lowest pure rotational transitions. By contrast, the much weaker [FeII] 26.0 micron fine structure transition traces faster, dissociative shocks; here, only a small fraction of the fast shock luminosity emerges as line radiation that can be detected with Spitzer/IRS.Comment: 38 pages including 17 figures. Accepted for publication in Ap

    Redox conditions and authigenic mineralization related to cold seeps in central Guaymas Basin, Gulf of California

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    Authigenic carbonate crusts, surface muds and bivalve shell fragments have been recovered from inactive and active recently discovered cold seep sites in central Guaymas Basin. In this study, for first time, redox conditions and fluid sources involved in mineral precipitation were investigated by analyzing the mineralogy and textures of surface samples, along with skeletal contents, and C, O and S isotopes variations. The d13C values of aragonitic bivalve shells and non-skeletal carbonate from some surface muds (1‰ to -3.7‰ V-PDB) suggest that carbonate precipitated from ambient dissolved inorganic carbon, whereas fibrous aragonite cement and non-skeletal carbonate from other sites are highly depleted in 13C (down to -47.6‰ V-PDB), suggesting formation via anaerobic oxidation of methane, characteristic of methane seepage environments. d18O in most of the carbonates varies from +1.4‰ to +3.2‰ V-PDB, indicating that they formed from slightly modified seawater. Some non-skeletal carbonate grains from surface muds have lower d18O values (-12.5‰ to -8.2‰ V-PDB) reflecting the influence of 18O-depleted pore water. Size distribution of pyrite framboids (mean value: 3.1¿µm) scattered within diatomaceous sinter suggests formation from anoxic-sulfidic bottom waters. d34S in pyrite is of -0.3‰ V-CDT compared to +46.6‰ V-CDT in barite, thus implying a fluid sulfate-sulfide fractionation of 21.3‰ that argues in favor of microbial sulfate reduction as the processes that mediated pyrite framboid formation, in a semi-closed system. Barite formation occurred through the mixing of reducing and Ba-rich seep fluids with a 34S-enriched sulfate pool that resulted from microbial sulfate reduction in a semi-closed system. The chemical composition of aragonite cement, barite and pyrite suggest mineral precipitation from modified seawater. Taken together, our data suggest that mineralization at the studied seep sites is controlled by the mixing of seawater with minor amounts of hydrothermal fluids, and oxygen-depleted conditions favoring anaerobic microbial processes.Peer ReviewedPostprint (author's final draft

    Macrocerebellum: Significance and Pathogenic Considerations

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    Macrocerebellum is a rare finding characterized by an abnormally large cerebellum. Only few patients with a syndromal or isolated macrocerebellum have been reported so far. This article aims to categorize the magnetic resonance imaging (MRI) findings, quantitate the macrocerebellum by volumetric analysis, characterize the neurological and dysmorphic features and cognitive outcome, and report the results of genetic analyses in children with macrocerebellum. All MR images were qualitatively evaluated for infratentorial and supratentorial abnormalities. Volumetric analysis was performed. Data about neurological and dysmorphic features, outcome, and genetic analysis were collected from clinical histories and follow-up examinations. Five patients were included. Volumetric analysis in three patients confirmed large cerebellar size compared to age-matched controls. MR evaluation showed that thickening of the cortical gray matter of the cerebellar hemispheres is responsible for the macrocerebellum. Additional infratentorial and supratentorial abnormalities were present in all patients. Muscular hypotonia, as well as impaired motor and cognitive development, was found in all patients, with ocular movement disorders in three of five patients. The five patients differed significantly in terms of dysmorphic features and involvement of extracerebral organs. Submicroscopic chromosomal aberrations were found in two patients. Macrocerebellum is caused by thickening of the cortical gray matter of the cerebellar hemispheres, suggesting that cerebellar granule cells may be involved in its development. Patients with macrocerebellum show highly heterogeneous neuroimaging, clinical, and genetic findings, suggesting that macrocerebellum is not a nosological entity, but instead represents the structural manifestation of a deeper, more basic biological disturbance common to heterogeneous disorder

    Predictors of Mortality in Head-Preserving Treatment for Dislocated Proximal Humerus Fractures: A Retrospective Analysis of 522 Cases with a Minimum Follow-Up of 5 Years

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    Purpose: Proximal humerus fractures (PHFs) are among the most common fractures in elderly patients, but there is still inadequate knowledge about mortality risk factors after such injuries. In order to provide the best possible therapy, individual risk factors have to be considered and evaluated thoroughly. There is still controversy regarding treatment decisions for proximal humerus fractures, particularly for the elderly. Methods: In this study, patient data from 522 patients with proximal humerus fractures were obtained from 2004 to 2014 at a Level 1 trauma centre. After a minimum follow-up of 5 years, the mortality rate was assessed, and independent risk factors were evaluated. Results: A total of 383 patients (out of 522) were included in this study. For our patient collective, the mean follow-up was at 10.5 ± 3.2 years. The overall mortality rate was 43.8% in our respondent group and was not significantly impacted by concomitant injuries. The binary logistic regression model showed an increased risk for mortality by 10% per life year, a 3.8 times higher mortality risk for men as well as for conservative treatment. The most powerful predictor was a Charlson Comorbidity Index of more than 2, with a 16 times higher mortality risk. Conclusions: Outstanding independent predictors of death in our patient collective were serious comorbidities, male patients, and conservative treatment. This patient-related information should influence the process of decision making for the individual treatment of patients with PHFs

    Molecular Characterization of Cancer Associated Fibroblasts in Prostate Cancer

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    Background: Stromal components surrounding epithelial cancer cells seem to play a pivotal role during epithelial-to-mesenchymal transition (EMT), tumor invasion, and metastases. To identify the molecular mechanisms underlying tumor–stroma interactions may yield novel therapeutic targets for prostate cancer. Methods: Gene expression profile of prostate-cancer associated fibroblast (PCAF) and prostate non-cancer associated fibroblast (PNAF) cells isolated from radical prostatectomy was performed by Illumina, analyzed, and further processed by Ingenuity®: IPA® software. qRT-PCR was performed on an independent set of 17 PCAF, 12 PNAF, and 12 fibroblast cell lines derived from patients with benign prostatic hyperplasia (BPHF). Results: Using microarray analysis, we found six upregulated genes and two downregulated genes in PCAFs compared to PNAFs. To validate microarray results, we performed qRT-PCR for the most significantly regulated genes involved in the modulation of proliferation and androgen resistance on an independent set of PNAF, PCAF, and BHPF samples. We confirmed the increased expression of SCARB1, MAPK3K1, and TGF-β as well as the decreased expression of S100A10 in PCAFs compared to PNAFs and BPHFs. Conclusions: These results provide strong evidence that the observed changes in the gene expression profile of PCAFs can contribute to functional alteration of adjacent prostate cancer cells

    Dot Immunobinding Assay for the Rapid Serodetection of Scedosporium/Lomentospora in Cystic Fibrosis Patients

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    The detection of Scedosporium/Lomentospora is still based on non-standardized low-sensitivity culture procedures. This fact is particularly worrying in patients with cystic fibrosis (CF), where these fungi are the second most common filamentous fungi isolated, because a poor and delayed diagnosis can worsen the prognosis of the disease. To contribute to the discovery of new diagnostic strategies, a rapid serological dot immunobinding assay (DIA) that allows the detection of serum IgG against Scedosporium/Lomentospora in less than 15 min was developed. A crude protein extract from the conidia and hyphae of Scedosporium boydii was employed as a fungal antigen. The DIA was evaluated using 303 CF serum samples (162 patients) grouped according to the detection of Scedosporium/Lomentospora in the respiratory sample by culture, obtaining a sensitivity and specificity of 90.48% and 79.30%, respectively; positive and negative predictive values of 54.81% and 96.77%, and an efficiency of 81.72%. The clinical factors associated with the results were also studied using a univariate and a multivariate analysis, which showed that Scedosporium/Lomentospora positive sputum, elevated anti-Aspergillus serum IgG and chronic Pseudomonas aeruginosa infection were significantly associated with a positive result in DIA, while Staphylococcus aureus positive sputum showed a negative association. In conclusion, the test developed can offer a complementary, rapid, simple and sensitive method to contribute to the diagnosis of Scedosporium/Lomentospora in patients with CF.This research was funded by the Basque Government, grant numbers IT1362-19 and IT1657-22. L.M-S and M.A have received a predoctoral grant from the Basque Government and L.A-F from the University of the Basque Country (UPV/EHU)
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