Selective interaction of a water soluble naphthalenediimide with single-walled carbon nanotubes

A water soluble naphthalenediimide (NDI) selectively interact with small diameter single-walled carbon nanotubes (SWCNTs), as demonstrated by Raman, along with absorption and emission spectroscopie

Biocompatible Collagen Paramagnetic Scaffold for Controlled Drug Release

A porous collagen-based hydrogel scaffold was prepared in the presence of iron oxide nanoparticles (NPs) and was characterized by means of infrared spectroscopy and scanning electron microscopy. The hybrid scaffold was then loaded with fluorescein sodium salt as a model compound. The release of the hydrosoluble species was triggered and accurately controlled by the application of an external magnetic field, as monitored by fluorescence spectroscopy. The biocompatibility of the proposed matrix was also tested by the MTT assay performed on 3T3 cells. Cell viability was only slightly reduced when the cells were incubated in the presence of the collagen-NP hydrogel, compared to controls. The economicity of the chemical protocol used to obtain the paramagnetic scaffolds as well as their biocompatibility and the safety of the external trigger needed to induce the drug release suggest the proposed collagen paramagnetic matrices for a number of applications including tissue engeneering and drug delivery

Concise, Single-Step Synthesis of Sulfur-Enriched Graphene: Immobilization of Molecular Clusters and Battery Applications

[Abstract]: The concise synthesis of sulfur-enriched Graphene for battery applications is reported. The direct treatment of graphene oxide (GO) with the commercially available Lawesson’s reagent produced sulfur-enriched-reduced GO (S-rGO). Various techniques, such as X-ray photoelectron spectroscopy (XPS), confirmed the occurrence of both sulfur functionalization and GO reduction. Also fabricated was a nanohybrid material by using S-rGO with polyoxometalate (POM) as a cathode-active material for a rechargeable battery. Transmission electron microscopy (TEM) revealed that POM clusters were individually immobilized on the S-rGO surface. This battery, based on a POM/S-rGO complex, exhibited greater cycling stability for the charge-discharge process tan a battery with nanohybrid materials positioned between the POM and nonenriched rGO. These results demonstrate that the use of sulfur-containing groups on a graphene surface can be extended to applications such as the catalysis of electrochemical reactions and electrodes in other battery systems.This work was financially supported by MEXT/JSPS KAKENHI (15K21073, 19K15539 to H.O., 16H06350, 16H02248 to H.S. and 18H04528, 17H03048, 18H04491 to H.Y.) and in part by research grants from Nippon Shokubai Co. Ltd., Kondo Zaidan, JGC-S Scholarship Foundation. We acknowledged financial support from the European Union’s Horizon2020 research and innovation program under Grant Agreements 696656 and 785219 Graphene Flagship. This work was also supported by the Spanish Ministry of Economy and Competitiveness MINECO (projects IJCI-2016-31113), by the University of Trieste, and Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM). MP, as the recipient of the AXA Chair, is grateful to the AXA Research Fund for financial support. This work was performed under the Maria de Maeztu Units of Excellence Program from the Spanish State Research Agency—Grant No. MDM-2017-0720. We also thank Prof. Yuta Nishina (Okayama University) for providing graphene oxide samples.MEXT/JSPS KAKENHI; 15K21073MEXT/JSPS KAKENHI; 19K15539MEXT/JSPS KAKENHI; 16H06350MEXT/JSPS KAKENHI; 16H02248MEXT/JSPS KAKENHI; 18H04528MEXT/JSPS KAKENHI; 17H03048MEXT/JSPS KAKENHI; 18H0449

Carbon Nanodot:Supramolecular electron donor-acceptor hybrids featuring Perylenediimides

We describe the formation of charge-transfer complexes that feature electron-donating carbon nanodots (CND) and electron-accepting perylenediimides (PDI). The functionalities of PDIs have been selected to complement those of CNDs in terms of electrostatic and \u3c0-stacking interactions based on oppositely charged ionic head groups and extended \u3c0-systems, respectively. Importantly, the contributions from electrostatic interactions were confirmed in reference experiments, in which stronger interactions were found for PDIs that feature positively rather than negatively charged head groups. The electronic interactions between the components in the ground and excited state were characterized in complementary absorption and fluorescence titration assays that suggest charge-transfer interactions in both states with binding constants on the order of 8 7104\u2009M 121 (25\u2005L\u2009g 121). Selective excitation of the two components in ultrafast pump probe experiments gave a 210\u2005ps lived charge-separated state

Microscopy and modelling investigations on the morphology of the biofilm exopolysaccharide produced by Burkholderia multivorans strain C1576

: Bacteria form very often biofilms where they embed in a self-synthesized matrix exhibiting a gel-like appearance. Matrices offer several advantages, including defence against external threats and the easiness of intercellular communication. In infections, biofilm formation enhances bacteria resistance against antimicrobials, causing serious clinical problems for patients' treatments. Biofilm matrices are composed of proteins, extracellular DNA, and polysaccharides, the latter being the major responsible for matrix architecture. The repeating unit of the biofilm polysaccharide synthesized by Burkholderia multivorans strain C1576 contains two mannoses and two sequentially linked rhamnoses, one of them 50 % methylated on C-3. Rhamnose, a 6-deoxysugar, has lower polarity than other common monosaccharides and its methylation further reduces polarity. This suggests a possible role of this polysaccharide in the biofilm matrix; in fact, computer modelling and atomic force microscopy studies evidenced intra- and inter-molecular non-polar interactions both within polysaccharides and with aliphatic molecules. In this paper, the polysaccharide three-dimensional morphology was investigated using atomic force microscopy in both solid and solution states. Independent evidence of the polymer conformation was obtained by transmission electron microscopy which confirmed the formation of globular compact structures. Finally, data from computer dynamic simulations were used to model the three-dimensional structure

Environmentally friendly approaches for chemical modification of carbon-based nanomaterials

Carbon-based nanomaterials are under investigation for different applications, which often demands their chemical modification such as introducing the amino-functional groups or removing carboxyl and hydroxyl groups. In this paper, we are presenting approaches for changing the structure of selected carbon-based nanomaterials in which the use of reactive toxic chemicals is avoided. The methods such as gamma irradiation, thermal treatment with a source of N atoms and nascent hydrogen reduction are studied as possible methods for modification of carbon-based nanomaterials. In the phase of the cleaning, again environmentally friendly approaches are used: filtration, centrifugation, and dialysis. Due to selected methods for both modification and cleaning, the presented approaches are environmentally friendly, they avoiding the use of both aggressive toxic chemical in the synthetic phases as well as organic solvents in the phase of cleaning. Thanks to the avoiding of dangers chemical, these methods can lead to the lowering of the waste chemicals producing in the long-term future

Metal-free dual-phase full organic carbon nanotubes/g-C 3 N 4 heteroarchitectures for photocatalytic hydrogen production

Hydrogen generation from water using solar energy has grown into a promising approach for sustainable energy production. Over the last years, graphitic carbon nitrides (g-C3N4, CN), polymers based on the heptazine-group, have been widely applied as photocatalysts for H2 evolution. The poor charge separation efficiency of CN is considered the major drawback. Here, we investigated the effect of coupling CN with different types of carbon nanotubes on the charge transfer properties and the photocatalytic H2 evolution. We used carbon nanotubes (CNTs) of different wall number (single (SWCNTs), double (DWCNTs) and multi-walled (MWCNTs) CNTs) for the development of full-organic CN based composite photocatalysts. Photoactivity was drastically affected by the content but more importantly by the nature of the CNTs. The SWCNTs functionalized CN composites were the most active presenting approximately 2\u20135 times higher H2 evolution than the corresponding DWCNTs and MWCNTs functionalized CN under both solar and pure visible light irradiation. Photoactivity was primarily controlled by the improved electronic properties linked with the abundance and stability of photogenerated charges as evidenced by electron paramagnetic resonance spectroscopy. Transient absorption spectroscopy verified the transfer of reactive electrons from CN to CNTs. CNTs functioned as electron acceptors improving charge separation. The data suggest that charge transfer is inversely proportional to the wall number of the CNTs and that photoactivity is directly controlled by the size at the nanoscale of the CNTs used. In the CNTs/CN nanocomposites, photogenerated electrons are transferred more efficiently from CN when SWCNTs are used, providing more available electrons for H2 production

Reductively PEGylated carbon nanomaterials and their use to nucleate 3D protein crystals: a comparison of dimensionality

A range of carbon nanomaterials, with varying dimensionality, were dispersed by a non-damaging and versatile chemical reduction route, and subsequently grafted by reaction with methoxy polyethylene glycol (mPEG) monobromides. The use of carbon nanomaterials with different geometries provides both a systematic comparison of surface modification chemistry and the opportunity to study factors affecting specific applications. Multi-walled carbon nanotubes, single-walled carbon nanotubes, graphite nanoplatelets, exfoliated few layer graphite and carbon black were functionalized with mPEG-Br, yielding grafting ratios relative to the nanocarbon framework between ca. 7 and 135 wt%; the products were characterised by Raman spectroscopy, TGA-MS, and electron microscopy. The functionalized materials were tested as nucleants by subjecting them to rigorous protein crystallization studies. Sparsely functionalized flat sheet geometries proved exceptionally effective at inducing crystallization of six proteins. This new class of nucleant, based on PEG grafted graphene-related materials, can be widely applied to promote the growth of 3D crystals suitable for X-ray crystallography. The association of the protein ferritin with functionalized exfoliated few layer graphite was directly visualized by transmission electron microscopy, illustrating the formation of ordered clusters of protein molecules critical to successful nucleation

The vocational rehabilitation of students in VTIs: the case of N. Aegean

The purpose of this research is to investigate the vocational integration of trainees in public Vocational Training Institutes (VTIs) by studying the case of trainees in the South Aegean region. This study primarily focuses on preparing young individuals for their entry into the labour market and their successful integration into the professional world. Through a literature review, the research records: •The relationship between vocational training received by students at public VTIs and their employment, analysing how training influences job choices and the professional development of graduates. •The quality of education provided by public VTIs and its relevance to success in the labour market, examining the levels of access to practical experience and skills acquired by students. •The support and professional guidance received by students during their training, which play a significant role in their professional development, and additionally, vocational integration programs that can help graduates find suitable job positions. The research methodology involves a case study comprising two parts: •A quantitative study using a specially designed questionnaire, administered before and after the trainees' education, and •A qualitative study using interview forms directed at a sample of 11 directors of VTIs and labour market authorities in the South Aegean, along with a secondary sample of 14 trainees from the same area. The questionnaire for the quantitative study was initially distributed to 246 trainees of corresponding VTIs before entering the job market and later to 171 graduates, a year after their market entry. The data processing presented the views of the trainees in the South Aegean VTIs regarding the reasons and influencing factors for their specific choice and necessity. The results related to the expectations from the operation of VTIs, according to literature and legislation supporting the VTIs institution, and findings regarding the trainees' experience during their education were also analysed. The analysis of the qualitative research results presents the views, expectations, and experiences of the trainees from their education at VTIs, following the corresponding questions of the quantitative study's questionnaire. It also includes the presentation of the opinions of VTI directors and labour market authorities in the South Aegean region regarding the VTIs institution and the functioning of the labour market in relation to the possibility of vocational integration of graduates. However, it is imperative to update the results of this study with new research efforts, as the data in initial vocational training and the labour market are changing rapidly. This is essential to ensure that graduates remain competitive by continuously adapting their skills and education to the current needs of the market.Σκοπός της παρούσας έρευνας είναι η διερεύνηση της επαγγελματικής αποκατάστασης των καταρτιζόμενων στα δημόσια Ινστιτούτα Επαγγελματικής Κατάρτισης (ΔΙΕΚ) μελετώντας την περίπτωση των καταρτιζόμενων στην περιφέρεια Νοτίου Αιγαίου καθώς αφορά την προετοιμασία κυρίως των νέων για την είσοδό τους στην αγορά εργασίας και την επιτυχή ενσωμάτωσή τους στον επαγγελματικό χώρο. Με τη βοήθεια της βιβλιογραφικής ανασκόπησης καταγράφονται: •Η σχέση μεταξύ της επαγγελματικής κατάρτισης που λαμβάνουν οι φοιτητές στα δημόσια ΙΕΚ και της απασχόλησής τους αναλύοντας πώς η κατάρτιση επηρεάζει τις επιλογές εργασίας και την επαγγελματική εξέλιξη των αποφοίτων. •Η ποιότητα της εκπαίδευσης που παρέχεται από τα δημόσια ΙΕΚ και η συνάφειά της με την επιτυχία στην αγορά εργασίας εξετάζοντας τα επίπεδα πρόσβασης σε πρακτική εμπειρία και δεξιότητες που αποκτούν οι σπουδαστές. •Η υποστήριξη που λαμβάνουν οι σπουδαστές κατά τη διάρκεια της εκπαίδευσής τους και η επαγγελματική καθοδήγηση οι οποίες παίζουν σημαντικό ρόλο στην επαγγελματική τους εξέλιξη και επιπλέον, προγράμματα επαγγελματικής αποκατάστασης που μπορούν να βοηθήσουν τους αποφοίτους να βρουν κατάλληλες θέσεις εργασίας. Η μεθοδολογία της έρευνας αφορά μελέτη περίπτωσης, η οποία περιλαμβάνει δυο μέρη: •κατά ένα μέρος μια ποσοτική έρευνα με χρήση ειδικά σχεδιασμένου ερωτηματολογίου, πριν και μετά την φοίτηση τους, και •κατά ένα μέρος ποιοτική έρευνα με χρήση δελτίου συνέντευξης που απευθύνθηκε σε ένα δείγμα με 11 διευθυντές ΔΙΕΚ και στελέχη φορέων της αγοράς εργασίας του Νοτίου Αιγαίου και σε ένα δευτερεύον δείγμα 14 καταρτιζόμενων από την αντίστοιχη περιοχή. Το ερωτηματολόγιο της ποσοτικής έρευνας απευθύνθηκε στην πρώτη φάση, πριν την είσοδο τους στην αγορά εργασίας, σε 246 καταρτιζόμενους των αντίστοιχων ΔΙΕΚ και στη δεύτερη φάση σε 171 απόφοιτους, ένα χρόνο μετά την είσοδο τους στην αγορά εργασίας. Κατά την επεξεργασία των δεδομένων ως προς τα δεδομένα της ποσοτικής έρευνας παρουσιάστηκαν οι απόψεις των καταρτιζόμενων στα ΔΙΕΚ του Νοτίου Αιγαίου τόσο για τους λόγους, όσο και για τους παράγοντες επιρροής για την συγκεκριμένη επιλογή και την αναγκαιότητα της. Επίσης, αναλύθηκαν τα αποτελέσματα αναφορικά με τις προσδοκίες από την λειτουργία των ΔΙΕΚ, σύμφωνα με τις προδιαγραφές οι οποίες τίθενται από τη βιβλιογραφία και τη νομοθεσία που υποστηρίζει τον θεσμό των ΔΙΕΚ και αποτελέσματα σχετικά με την εμπειρία των καταρτιζόμενων από την φοίτηση τους στα ΔΙΕΚ επιμόρφωσης στα οποία συμμετέχουν. Η ανάλυση των αποτελεσμάτων της ποιοτικής έρευνας παρουσιάζει τα αποτελέσματα αναφορικά με τις απόψεις, προσδοκίες και εμπειρίες των καταρτιζόμενων από την φοίτηση τους στα ΔΙΕΚ σε συνέχεια των αντίστοιχων ερωτήσεων του ερωτηματολογίου της ποσοτικής έρευνας. Περιλαμβάνεται και η παρουσίαση των απόψεων των διευθυντών ΔΙΕΚ και των στελεχών από φορείς της αγοράς εργασίας στην περιοχή του Νοτίου Αιγαίου για τον θεσμό των ΔΙΕΚ και την λειτουργία της αγοράς εργασίας σε σχέση με την δυνατότητα επαγγελματικής αποκατάστασης των αποφοίτων. Είναι όμως επιβεβλημένη και η επικαιροποίηση των αποτελεσμάτων της παρούσας με νέες ερευνητικές προσπάθειες, μιας και τα δεδομένα στην αρχική επαγγελματική κατάρτιση αλλά και την αγορά εργασίας αλλάζουν με γρήγορους ρυθμούς, ώστε οι απόφοιτοι να παραμείνουν ανταγωνιστικοί προσαρμόζοντας συνεχώς τις δεξιότητες και την εκπαίδευσή τους στις τρέχουσες ανάγκες της αγοράς