Synthesis, characterization and assessment of hydrophilic oxidized carbon nanodiscs in bio-related applications

Oxidation of industrially prepared carbon nanodiscs using a simple, versatile, and reproducible approach based on the Staudenmaier method yields a new hydrophilic form of nanocarbon. As a result of the strong acid treatment, which also enables the separation of carbon nanodiscs from the mixed starting material, the graphene planes detach from the discs, while the surface of the carbon nanodiscs is decorated with various oxygen-containing functional polar groups. Thus, the completely insoluble carbon nanodiscs are converted to a hydrophilic derivative dispersable in many polar solvents, including water. The new carbon structure is expected to have a wide range of applications in several fields including bioapplications. To this end, the functionalized carbon nanodiscs exhibit very low cytotoxicity, while they achieve high drug loadings, enabling their application as an effective drug nanocarrier. Furthermore, the carbon disks were evaluated as supports in nanobiocatalytic applications, increasing significantly the stability of the systems, due to carbon disks' nano-sized dimensions

Association between antiphospholipid antibodies and vascular complications in hemodialyzed diabetic patients

The dysfunction of arteriovenous communications of patients requiring hemodialysis is an important factor of excess morbidity and mortality but also of increased health care cost. This phenomenon is observed in accesses made by native vessels (fistulas) and those made with the use of PTFE grafts.In an attempt to explain the phenomenon of thrombosis of arteriovenous communications, we investigated the presence of antiphospholipid antibodies, in particular IgG and IgM antibodies against β2GPI as well as IgG and IgM antibodies against prothrombin, in patients with renal failure and their association with the thrombosis and dysfunction of these communications.The study included 160 patients, divided into 3 groups, diabetic hemodialyzed patients, non-diabetic hemodialyzed patients and non-hemodialyzed diabetic patients with renal failure.Thrombosis of arteriovenous accesses occurred in 42 out of 104 hemodialyzed patients (40.38%). The fistulas appear to thrombose less frequently than grafts (31.76% vs. 91.67%, p=0.0001), both in men and in women. This phenomenon is not related to the presence of diabetes (46.29% for the group of diabetic hemodialyzed patients and 34% for the non-diabetic hemodialyzed ones, p = 0.234). The prevalence of positive antibodies to β2GPI in diabetic hemodialyzed and non-diabetic hemodialyzed subjects does not differ significantly, implying that diabetes mellitus does not have an autoimmune effect at this level.Regarding the quantitative measurement of antiprothrombin antibodies, we found increased levels in the group of non-hemodialyzed patients, compared to the hemodialyzed patients (p=0.045).Our study showed high rates of arteriovenous thrombosis in hemodialyzed patients. The only association of these thromboses found was with the type of arteriovenous communications, without any association with the titre of antiphospholipid antibodies. There is no reason to measure the level of antiphospholipid antibodies in hemodialyzed patients.Η δυσλειτουργία των αρτηριοφλεβικών επικοινωνιών στους αιμοκαθαιρόμενους ασθενείς, είναι ένας σημαντικός παράγοντας αύξησης της νοσηρότητας και θνητότητάς τους αλλά και αύξησης του συνολικού κόστους υγείας. Το φαινόμενο αυτό παρατηρείται σε επικοινωνίες για τη δημιουργία των οποίων χρησιμοποιούνται τα γηγενή αγγεία (φίστουλες) αλλά και σε εκείνες που παρεμβάλλονται μοσχεύματα.Σε μια προσπάθεια εξήγησης του φαινομένου της θρόμβωσης των αρτηριοφλεβικών επικοινωνιών, διερευνήσαμε την ύπαρξη αντιφωσφολιπιδικών αντισωμάτων και πιο συγκεκριμένα αντισωμάτων IgG και IgM έναντι της β2GPI, καθώς και αντισωμάτων IgG και IgM έναντι της προθρομβίνης, σε ασθενείς με νεφρική ανεπάρκεια, καθώς και τη συσχέτισή τους με τη θρόμβωση και τη δυσλειτουργία των επικοινωνιών αυτών. Στη μελέτη συμπεριλήφθηκαν 160 ασθενείς, οι οποίοι χωρίστηκαν σε 3 ομάδες, δηλαδή σε αιμοκαθαιρόμενους διαβητικούς ασθενείς, σε αιμοκαθαιρόμενους μη διαβητικούς ασθενείς και σε μη αιμοκαθαιρόμενους διαβητικούς ασθενείς με νεφρική ανεπάρκεια. Θρόμβωση της αρτηριοφλεβικής επικοινωνίας συνέβη σε 42 από τους 104 αιμοκαθαιρόμενους ασθενείς της μελέτης μας (40,38%) και μάλιστα οι φίστουλες φαίνεται να θρομβώνονται με μικρότερη συχνότητα από τα μοσχεύματα (31,76% vs 91,67%, p=0.0001), τόσο στους άνδρες όσο και στις γυναίκες. Το φαινόμενο αυτό δεν φαίνεται να σχετίζεται με την ύπαρξη σακχαρώδη διαβήτη (46,29% για την ομάδα αιμοκαθαιρόμενων διαβητικών και 34% για την αιμοκαθαιρόμενων μη διαβητικών ασθενών, p=0.234). Η συχνότητα ύπαρξης θετικών αντισωμάτων έναντι β2GPI σε διαβητικούς αιμοκαθαιρόμενους και σε μη διαβητικούς αιμοκαθαιρόμενους, δεν διαφέρει σημαντικά, καταλήγοντας στο συμπέρασμα πως ο σακχαρώδης διαβήτης δεν ευθύνεται για φαινόμενα αυτοανοσίας, σε αυτό το επίπεδο. Όσον αφορά στην ανάλυση των ποσοτικών μετρήσεων των αντισωμάτων έναντι της προθρομβίνης, είδαμε αυξημένα επίπεδα αυτών στην ομάδα των μη αιμοκαθαιρόμενων ασθενών, σε σχέση με τους αιμοκαθαιρόμενους (p=0.045). Τελικά, η μελέτη μας έδειξε υψηλά ποσοστά θρόμβωσης αρτηριοφλεβικών επικοινωνιών σε αιμοκαθαιρόμενους ασθενείς. Η μόνη συσχέτιση που βρέθηκε είναι με τον τύπο των αρτηριοφλεβικών επικοινωνιών, χωρίς να υπάρχει συσχέτιση των θρομβώσεων με τον τίτλο των αντιφωσφολιπιδικών αντισωμάτων. Για το λόγο αυτό, δεν θεωρούμε πως υπάρχει λόγος μέτρησης των αντιφωσφολιπιδικών αντισωμάτων σε αιμοκαθαιρόμενους ασθενείς

Operational State Recognition of a DC Motor Using Edge Artificial Intelligence

Edge artificial intelligence (EDGE-AI) refers to the execution of artificial intelligence algorithms on hardware devices while processing sensor data/signals in order to extract information and identify patterns, without utilizing the cloud. In the field of predictive maintenance for industrial applications, EDGE-AI systems can provide operational state recognition for machines and production chains, almost in real time. This work presents two methodological approaches for the detection of the operational states of a DC motor, based on sound data. Initially, features were extracted using an audio dataset. Two different Convolutional Neural Network (CNN) models were trained for the particular classification problem. These two models are subject to post-training quantization and an appropriate conversion/compression in order to be deployed to microcontroller units (MCUs) through utilizing appropriate software tools. A real-time validation experiment was conducted, including the simulation of a custom stress test environment, to check the deployed models’ performance on the recognition of the engine’s operational states and the response time for the transition between the engine’s states. Finally, the two implementations were compared in terms of classification accuracy, latency, and resource utilization, leading to promising results

Design of embedded systems with complex task dependencies and shared resource interference (Short Paper)

International audienceLanguages for embedded systems ensure predictable timing behavior by specifying constraints based on either data streaming or reactive control models of computation. Moreover, various toolsets facilitate the incremental integration of application functionalities and the system design by evolutionary refinement and model-based code generation. Modern embedded systems involve various sources of interference in shared resources (e.g. multicores) and advanced real-time constraints , such as mixed-criticality levels. A sufficiently expressive model-ing approach for complex dependency patterns between real-time tasks is needed along with a formal analysis of models for runtime resource managers with timing constraints. Our approach utilizes a model of computation , called Fixed-Priority Process Networks, which ensures functional determinism by unifying streaming and reactive control within a timed automata framework. The tool flow extends the open source TASTE tool-suite with model transformations to the BIP language and code generation tools. We outline the use of our flow on the design of a spacecraft on-board application running on a quad-core LEON4FT processor

Intercalation Study of Low-Molecular-Weight Hyperbranched Polyethyleneimine into Graphite Oxide

We report for the first time the intercalation of low-molecular-weight hyperbranched polyethyleneimine (PEI) into graphite oxide (GO) for the facile, bulk synthesis of novel graphene-based hybrid (GO-PEI) materials exhibiting tailored interlayer galleries. The size of the intercalant as well as the loading in GO were systematically investigated to determine their contribution to the basal spacing of the resulting materials. Powder X-ray diffraction measurements demonstrated the generation of constrained hybrid systems along the c axis that exhibit considerably increased interlayer distances compared with the starting, pristine GO. The results of X-ray photoelectron and FTIR studies are consistent with a "grafting-to" process of the intercalated PEI with the oxygen functional groups present along the GO framework. Furthermore, it was found that a great number of the nitrogen-containing groups in PEI still remain available within the newly formed, confined micro-environment of intercalated GO galleries. The increased surface area of the GO-PEI hybrids in conjunction with the remaining available active groups of intercalated PEI render the synthesised hybrids very attractive candidates as nanostructured adsorbents

Design of embedded systems with complex task dependencies and shared resource interference (Short Paper)

International audienceLanguages for embedded systems ensure predictable timing behavior by specifying constraints based on either data streaming or reactive control models of computation. Moreover, various toolsets facilitate the incremental integration of application functionalities and the system design by evolutionary refinement and model-based code generation. Modern embedded systems involve various sources of interference in shared resources (e.g. multicores) and advanced real-time constraints , such as mixed-criticality levels. A sufficiently expressive model-ing approach for complex dependency patterns between real-time tasks is needed along with a formal analysis of models for runtime resource managers with timing constraints. Our approach utilizes a model of computation , called Fixed-Priority Process Networks, which ensures functional determinism by unifying streaming and reactive control within a timed automata framework. The tool flow extends the open source TASTE tool-suite with model transformations to the BIP language and code generation tools. We outline the use of our flow on the design of a spacecraft on-board application running on a quad-core LEON4FT processor

Engineering Commercial TiO₂ Powder into Tailored Beads for Efficient Water Purification

In this study, efficient commercial photocatalyst (Degussa P25) nanoparticles were effectively dispersed and stabilized in alginate, a metal binding biopolymer. Taking advantage of alginate’s superior metal chelating properties, copper nanoparticle-decorated photocatalysts were developed after a pyrolytic or calcination-sintering procedure, yielding ceramic beads with enhanced photocatalytic and mechanical properties, excellent resistance to attrition, and optimized handling compared to powdered photocatalysts. The morphological and structural characteristics were studied using LN2 porosimetry, SEM, and XRD. The abatement of an organic pollutant (Methyl Orange, MO) was explored in the dark and under UV irradiation via batch experiments. The final properties of the photocatalytic beads were defined by both the synthesis procedure and the heat treatment conditions, allowing for their further optimization. It was found that the pyrolytic carbon residuals enabled the adhesion of the TiO2 nanoparticles, acting as binder, and increased the MO adsorption capacity, leading to increased local concentration in the photocatalyst vicinity. Well dispersed Cu nanoparticles were also found to enhance photocatalytic activity. The prepared photocatalysts exhibited increased MO adsorption capacity (up to 3.0 mg/g) and also high photocatalytic efficiency of about 50% MO removal from water solutions, reaching an overall MO rejection of about 80%, at short contact times (3 h). Finally, the prepared photocatalysts kept their efficiency for at least four successive photocatalytic cycles

Fabrication of Antibacterial Poly(Vinyl Alcohol) Nanocomposite Films Containing Dendritic Polymer Functionalized Multi-Walled Carbon Nanotubes

A series of poly(vinyl alcohol) (PVA) nanocomposite films containing quaternized hyperbranched polyethyleneimine (PEI) functionalized multi-walled carbon nanotubes (ox-CNTs@QPEI) are prepared by solvent casting technique. The modified carbon-based material exhibits high aqueous solubility, due to the hydrophilic character of the functionalized hyperbranched dendritic polymer. The quaternized PEI successfully wraps around nanotube walls as polycations provide electrostatic repulsion. Various contents of ox-CNTs@QPEI ranging from 0.05 to 1.0% w/w were employed to prepare functionalized PVA nanocomposites. The developed films exhibit adequate optical transparency, improved mechanical properties and extremely high antibacterial behavior due to the excellent dispersion of the functionalized CNTs into the PVA matrix

Intermittent Inotropic Infusions Combined With Prophylactic Oral Amiodarone for Patients With Decompensated End-stage Heart Failure

Background: Concern has been raised regarding the mortality and ethics related to the treatment of patients with end-stage chronic heart Failure with chronic intermittent intravenous inotropic agents. We examined whether intermittent inotropic agents combined with oral amiodarone to prevent the proarrhythmic effect of inotropic agents results in better outcomes. Methods: The study included 162 patients with decompensated end-stage chronic heart failure, who could be weaned from an initial 72-hour infusion of intravenous inotropes. Group 1 included 140 patients, who entered a 6-month program of weekly intermittent intravenous inotropic agents plus oral amiodarone, 200 mg twice a day. Group 2 included 22 patients, who were treated with optimal conventional therapy and were hospitalized for administration of intravenous medications as needed. Results: The baseline characteristics of groups I versus 2, including New York Heart Association functional class (IV in both groups), admission systolic arterial blood pressure (99 14 vs. 97 13 mm Hg), right atrial pressure (13 +/- 6 vs. 14 +/- 6 mm Hg), pulmonary capillary wedge rircssure (28 +/- 7 vs, 31 10 mm Hg), serum sodium (136 +/- 7 vs. 139 +/- 6 mEq/L) and scrum creatinine (1.7 +/- 0.8 vs. 1.8 +/- 1.8 mg/dL.), wen., similar. The 6-month (51% vs. 18%) and 1-year (36% VS. 9%) survival rates were significantly higher (P = 0.001 for both) in group 1 than in group 2. In addition, patients treated with intermittent intravenous inotropic agents improved their functional and hemodynamic status. Conclusions: intermittent intravenous inotropic agents combined with prophylactic oral amiodarone seem to improve the outcomes of patients with end-stage chronic heart failure. Further research is warranted to elucidate whether this treatment strategy should be considered as a standard therapy in patients with refractory end-stage heart failure