293 research outputs found

    Destabilization and removal of immobilized enzymes adsorbed onto polyethersulfone ultrafiltration membranes by salt solutions

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    In this work the effectiveness of two saline solutions (NaCl and Na2SO4) to clean a permanently hydrophilic polyethersulfone (PESH) ultrafiltration (UF) membrane with a molecular weight cut-off (MWCO) of 30 kDa previously fouled with enzymatic solutions was investigated. The influence of protein concentration in the enzymatic solution during the fouling step and the effect of salt type during the cleaning procedure were studied. The protein aggregation was analyzed in solution and onto the membrane surface by using several techniques including Dynamic Light Scattering (DLS), Atomic Force Microscopy (AFM) and Infrared Spectroscopy with Attenuated Total Reflectance (ATR-FTIR). In addition, mechanisms that dominate membrane fouling were studied by fitting some mathematical models (Hermia's models adapted to crossflow filtration, a combined model based on the complete blocking and cake formation equations and a resistance-in-series model) to the experimental data. Fouling results showed that the complete blocking/adsorption on membrane surface was the predominant fouling mechanism. Regarding the cleaning results, higher cleaning efficiency and low residual protein concentration was obtained with NaCl solutions for all the feed solutions tested due to the favorable interaction between Cl and proteins.Maria-Jose Corbaton-Baguena wishes to gratefully acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness through the grant EEBB-I-14-09011 (project CTM2010-20186). The authors acknowledge the European Union, Fondo Europeo di Sviluppo Regionale, The Ministero dell'Istruzione, dell'Universita e della Ricerca - MIUR, The Ministero dello Svilupppo Economic - MSE - for the financial support to the project "Sistemi tecnologici avanzati e processi integrati della filiera olivicola per la valorizzazione dei prodotti e dei sottoprodotti, lo sviluppo di nuovi settori e la creazione di sistemi produttivi Eco-compatibili" (PON Olio Piu, PON01_01545), within the framework PON Ricerca e Competitivita 2007-2013.Corbatón Báguena, MJ.; Gugliuzza, A.; Cassano, A.; Mazzei, R.; Giorno, L. (2015). Destabilization and removal of immobilized enzymes adsorbed onto polyethersulfone ultrafiltration membranes by salt solutions. Journal of Membrane Science. 486:207-214. https://doi.org/10.1016/j.memsci.2015.03.061S20721448

    A new score for improving cardiovascular risk prediction and prevention.

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    The ultrasonographic detection of subclinical atherosclerosis (scATS) at carotid and femoral vascular sites using the atherosclerosis burden score (ABS) improves the risk stratification for atherosclerotic cardiovascular disease beyond traditional cardiovascular (CV) risk factors. However, its predictive value should be further enhanced. We hypothesize that combining the ABS and the Framingham risk score (FHRS) to create a new score called the FHRABS will improve CV risk prediction and prevention. We aim to investigate if incorporating the ABS into the FHRS improved CV risk prediction in a primary prevention setting. 1024 patients were included in this prospective observational cohort study. Carotid and femoral plaques were ultra-sonographic detected. Major incident cardiovascular events (MACEs) were collected. The receiver operating characteristic curve (ROC-AUC) and Youden's index (Ysi) were used to compare the incremental contributions of each marker to predict MACEs. After a median follow-up of 6.0 ± 3.3 years, 60 primary MACEs (5.8%) occurred. The ROC-AUC for MACEs prediction was significantly higher for the FHRABS (0.74, p < 0.024) and for the ABS (0.71, p < 0.013) compared to the FHRS alone (0.71, p < 0.46). Ysi or the FHRABS (42%, p < 0.001) and ABS (37%, p < 0.001) than for the FHRS (31%). Cox proportional-hazard models showed that the CV predictive performance of FHRS was significantly enhanced by the ABS (10.8 vs. 5.5, p < 0.001) and FHRABS (HR 23.30 vs. 5.50, p < 0.001). FHRABS is a useful score for improving CV risk stratification and detecting patients at high risk of future MACEs. FHRABS offers a simple-to-use, and radiation-free score with which to detect scATS in order to promote personalized CV prevention

    Does Ionized Magnesium Offer a Different Perspective Exploring the Association between Magnesemia and Targeted Cardiovascular Risk Factors?

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    Evidence of the association of magnesium (Mg) with arterial stiffness has so far been conflicting. The interplay between hypertension and elevated body mass index (BMI), with hypomagnesemia, instead, has been described in the literature in a more consistent way. Our study aims at revisiting the correlations between blood Mg levels and hemodynamic and body composition parameters in the general population, exploring the sensitivity profile of ionized Mg (Ion-Mg) compared to total Mg (Tot-Mg). We collected data from 755 subjects randomly chosen from a Swiss population previously described and stratified our sample into four equivalent classes according to ionized (whole blood) and total (serum) magnesium. After correcting for age, statistically significant differences emerged between: (i) Tot-Mg ≤ 0.70 and 0.81 ≤ Tot-Mg ≤ 0.90 for cf-PWV (p = 0.039); (ii) Tot-Mg ≤ 0.70 and Tot-Mg ≥ 0.91 for o-PWV (p = 0.046). We also found a statistically significant difference among groups of Ion-Mg values for the 24 h extremes of systolic blood pressure (p = 0.048) and among groups of Tot-Mg for BMI (p = 0.050). Females showed significantly lower levels of total magnesium (p = 0.035) and ionized magnesium (p < 0.001) than males. The overall agreement between magnesium analysis methods was 64% (95%CI: 60.8−67.7%). Our results confirm that Ion-Mg compared with Tot-Mg offers a different profile in detecting both correlations with hemodynamic and body composition parameters and dysmagnesemias. Lower levels of magnesium were associated with worse arterial aging parameters, larger 24 h blood pressure excursions, and higher BMI. Ion-Mg was superior in detecting the correlation with blood pressure only. Considering Ion-Mg as a more specific marker of the magnesium status, and the partially contradictory results of our explorative cross-sectional study, to avoid confounding factors and misinterpretations, ionized magnesium should be used as reference in future studies

    New Zinc-Based Active Chitosan Films: Physicochemical Characterization, Antioxidant, and Antimicrobial Properties

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    The improvement of the antioxidant and antimicrobial activities of chitosan (CS) films can be realized by incorporating transition metal complexes as active components. In this context, bioactive films were prepared by embedding a newly synthesized acylpyrazolonate Zn(II) complex, [Zn(QPhtBu)2(MeOH)2], into the eco-friendly biopolymer CS matrix. Homogeneous, amorphous, flexible, and transparent CS@Znn films were obtained through the solvent casting method in dilute acidic solution, using different weight ratios of the Zn(II) complex to CS and characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR), Raman, and scanning electron microscopy (SEM) techniques. The X-ray single-crystal analysis of [Zn(QPhtBu)2(MeOH)2] and the evaluation of its intermolecular interactions with a protonated glucosamine fragment through hydrogen bond propensity (HBP) calculations are reported. The effects of the different contents of the [Zn(QPhtBu)2(MeOH)2] complex on the CS biological proprieties have been evaluated, proving that the new CS@Znn films show an improved antioxidant activity, tested according to the DPPH method, with respect to pure CS, related to the concentration of the incorporated Zn(II) complex. Finally, the CS@Znn films were tried out as antimicrobial agents, showing an increase in antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus) with respect to pure CS, when detected by the agar disk-diffusion method

    Characterization of a Bacillus anthracis spore coat-surface protein that influences coat-surface morphology

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    Bacterial spores are encased in a multilayered proteinaceous shell, called the coat. In many Bacillus spp., the coat protects against environmental assault and facilitates germination. In Bacillus anthracis , the spore is the etiological agent of anthrax, and the functions of the coat likely contribute to virulence. Here, we characterize a B. anthracis spore protein, called CotΒ, which is encoded only in the genomes of the Bacillus cereus group. We found that CotΒ is synthesized specifically during sporulation and is assembled onto the spore coat surface. Our analysis of a cotΒ null mutant in the Sterne strain reveals that CotΒ has a role in determining coat-surface morphology but does not detectably affect germination. In the fully virulent Ames strain, a cotΒ null mutation has no effect on virulence in a murine model of B. anthracis infection.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72138/1/j.1574-6968.2008.01380.x.pd

    Design, optimization and experimental characterization of RF injectors for high brightness electron beams and plasma acceleration

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    In this article, we share our experience related to the new photo-injector commissioning at the SPARC\_LAB test facility. The new photo-injector was installed into an existing machine and our goal was not only to improve the final beam parameters themselves but to improve the machine handling in day-to-day operations as well. Thus, besides the pure beam characterization, this article contains information about the improvements, that were introduced into the new photo-injector design from the machine maintenance point of view, and the benefits, that we gained by using the new technique to assemble the gun itself

    YwdL in Bacillus cereus: Its Role in Germination and Exosporium Structure

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    In members of the Bacillus cereus group the outermost layer of the spore is the exosporium, which interacts with hosts and the environment. Efforts have been made to identify proteins of the exosporium but only a few have so far been characterised and their role in determining spore architecture and spore function is still poorly understood. We have characterised the exosporium protein, YwdL. ΔywdL spores have a more fragile exosporium, subject to damage on repeated freeze-thawing, although there is no evidence of altered resistance properties, and coats appear intact. Immunogold labelling and Western blotting with anti-YwdL antibodies identified YwdL to be located exclusively on the inner surface of the exosporium of B. cereus and B. thuringiensis. We conclude that YwdL is important for formation of a robust exosporium but is not required to maintain the crystalline assembly within the basal layer or for attachment of the hairy nap structure. ΔywdL spores are unable to germinate in response to CaDPA, and have altered germination properties, a phenotype that confirms the expected defect in localization of the cortex lytic enzyme CwlJ in the coat
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