8 research outputs found
Thermal scanning probe lithography
No full textThermal scanning probe lithography (tSPL) is a nanofabrication method for the chemical and physical nanopatterning of a large variety of materials and polymer resists with a lateral resolution of 10 nm and a depth resolution of 1 nm. In this Primer, we describe the working principles of tSPL and highlight the characteristics that make it a powerful tool to locally and directly modify material properties in ambient conditions. We introduce the main features of tSPL, which can pattern surfaces by locally delivering heat using nanosized thermal probes. We define the most critical patterning parameters in tSPL and describe post-patterning analysis of the obtained results. The main sources of reproducibility issues related to the probe and the sample as well as the limitations of the tSPL technique are discussed together with mitigation strategies. The applications of tSPL covered in this Primer include those in biomedicine, nanomagnetism and nanoelectronics; specifically, we cover the fabrication of chemical gradients, tissue-mimetic surfaces, spin wave devices and field-effect transistors based on two-dimensional materials. Finally, we provide an outlook on new strategies that can improve tSPL for future research and the fabrication of next-generation devices
Giant Increase of Hardness in Silicon Carbide by Metastable Single Layer Diamond-Like Coating
No full text: Silicon carbide (SiC) is one of the hardest known materials. Its exceptional mechanical properties combined with its high thermal conductivity make it a very attractive material for a variety of technological applications. Recently, it is discovered that two-layer epitaxial graphene films on SiC can undergo a pressure activated phase transition into a sp3 diamene structure at room temperature. Here, it is shown that epitaxial graphene films grown on SiC can increase the hardness of SiC up to 100% at low loads (up to 900 μN), and up to 30% at high loads (10 mN). By using a Berkovich diamond indenter and nanoindentation experiments, it is demonstrated that the 30% increase in hardness is present even for indentations depths of 175 nm, almost three hundred times larger than the graphene film thickness. The experiments also show that the yield point of SiC increases up to 77% when the SiC surface is coated with epitaxial graphene. These improved mechanical properties are explained with the formation of diamene under the indenter's pressure
A Polymer Canvas with the Stiffness of the Bone Matrix to Study and Control Mesenchymal Stem Cell Response
No full text: The possibility to reproduce in vitro the complex multiscale physical features present in the human tissues creates novel opportunities for biomedical advances and fundamental understanding of cell-environment interfaces and interactions. While stiffness has been recognized as a key property in influencing cell behavior, so far systematic studies on the role of stiffness have been limited to values in the KPa-MPa range, significantly below the stiffness of bone. Here, we report a platform enabling the tuning and control of the stiffness of a biocompatible polymeric interface up to values characteristic of the bone tissue, which are in the GPa range. The ability to fine tune the stiffness up to these large values is achieved by using extremely thin polymer films on glass and cross-linking the films using UV light irradiation. We show that a higher stiffness is related to better adhesion, proliferation, and osteogenic differentiation, and that it is also possible to switch on/off cell attachment and growth by solely tuning the stiffness of the interface, without any surface chemistry or topography modification. Since the stiffness is tuned directly by UV irradiation, this platform is ideal for rapid and simple stiffness patterning, and stiffness gradients fabrication. This materials platform represents an innovative tool for combinatorial studies of the synergistic effect of tissue environmental cues on cell behavior, and creates new opportunities for next generation biosensors, single-cell patterning, and lab-on-a-chip devices. This article is protected by copyright. All rights reserved
Guida alle macrofite acquatiche del Friuli Venezia Giulia I - Piante vascolari
No full textLa Direttiva Quadro sulle Acque (2000/60/CE), recepita in Italia dal DL. 152/2006, ha introdotto lo
studio delle macrofite acquatiche nella valutazione dello stato ecologico delle acque interne, basato
sui criteri tecnici del DM 260/2011. Per i corsi d'acqua è previsto l'uso dell'Indice Biologique
Macrophytique en Rivière IBMR (AFNOR, 2003), per i laghi degli indici MTIspecies e
MacroIMMI (CNR-ISE, 2009). La certificazione di qualità delle analisi biologiche richiede
strumenti conoscitivi adeguati: la creazione di chiavi informatizzate è una tappa fondamentale.
Questa guida è stata sviluppata dal Dipartimento di Scienze della Vita dell'Università di Trieste e da
ARPA Friuli Venezia Giulia come supporto all'identificazione della flora acquatica regionale.
Risulta dalla condivisione delle conoscenze dell'ateneo giuliano con l'esperienza dei tecnici ARPA
FVG nell'ambito delle attività di biomonitoraggio per il Piano Regionale di Tutela delle Acque.
Le macrofite acquatiche comprendono vegetali molto diversi: alghe macroscopicamente visibili,
muschi, epatiche e piante vascolari, a cui è dedicata questa guida.
L'elenco floristico comprende taxa tipici di ambienti lotici e lentici, creato in fasi successive. Una
prima lista deriva dal confronto tra la quella utilizzata per il calcolo dell'IBMR e la lista delle
macrofite acquatiche dei corsi d'acqua italiani pubblicata da ENEA (RT/2009/23/ENEA). La
successiva comparazione tra i dati dell'Atlante Corologico del Friuli Venezia Giulia (Poldini 2002)
ed una lista risultante da rilievi condotti nel 2009-2010 da ARPA FVG, hanno portato all'elenco di
244 taxa inclusi in questa guida. La suddivisione in Famiglie segue Angiosperm Phylogeny Group
III (2009)
Cost and Time Effective Lithography of Reusable Millimeter Size Bone Tissue Replicas With Sub‐15 nm Feature Size on A Biocompatible Polymer
No full textTissue Engineering: Cost and Time Effective Lithography of Reusable Millimeter Size Bone Tissue Replicas With Sub‐15 nm Feature Size on A Biocompatible Polymer (Adv. Funct. Mater. 19/2021)
No full textDNA sequence and taxonomic gap analyses to quantify the coverage of aquatic cyanobacteria and eukaryotic microalgae in reference databases: Results of a survey in the Alpine region
No full textThe taxonomic identification of organisms based on the amplification of specific genetic markers (metabarcoding) implicitly
requires adequate discriminatory information and taxonomic coverage of environmental DNA sequences in
taxonomic databases. These requirements were quantitatively examined by comparing the determination of
cyanobacteria and microalgae obtained by metabarcoding and lightmicroscopy. Weused planktic and biofilm samples
collected in 37 lakes and 22 rivers across the Alpine region.We focused on two of the most used and best represented
genetic markers in the reference databases, namely the 16S rRNA and 18S rRNA genes. A sequence gap analysis using
blastn showed that, in the identity range of 99–100%, approximately 30% (plankton) and 60% (biofilm) of the sequences
did not find any close counterpart in the reference databases (NCBI GenBank). Similarly, a taxonomic gap
analysis showed that approximately 50% of the cyanobacterial and eukaryotic microalgal species identified by light
microscopy were not represented in the reference databases. In both cases, themagnitude of the gaps differed between
the major taxonomic groups. Even considering the species determined under the microscope and represented in the
reference databases, 22% and 26% were still not included in the results obtained by the blastn at percentage levels
of identity≥95% and≥97%, respectively. The main causes were the absence of matching sequences due to amplification
and/or sequencing failure and potential misidentification in the microscopy step. Our results quantitatively
demonstrated that in metabarcoding the main obstacles in the classification of 16S rRNA and 18S rRNA sequences
and interpretation of high-throughput sequencing biomonitoring data were due to the existence of important gaps
in the taxonomic completeness of the reference databases and the short length of reads. The study focused on the Alpine
region, but the extent of the gaps could be much greater in other less investigated geographic areas
Cyanobacterial blooms in the Po River basin and the eastern Alps
No full textIn this paper, we briefly describe episodes of cyanobacterial blooms that have occurred in lakes of northern Italy since 2000. In addition to listing the species involved in these blooms, we provide information on the trophic and ecological status of the water bodies and the presence of algal toxins. Furthermore, we report an example of a risk assessment effort aimed at developing a quality control system for water intended for human consumption. The use of high-frequency monitoring techniques, integrated with predictive modelling, remote sensing, and molecular analysis for species identification, is becoming increasingly important in the context of the effects of ongoing climate change
