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Robot Apocalypse

Professor Stephen Hawking has pleaded with world leaders to keep technology under control before it destroys humanity.

mercoledì 4 marzo 2015

NANO REVOLUTION


Saranno pronti fra tre anni, e potrebbero entrare in commercio fra dieci, i nuovi materiali basati sul materiale sottile come un atomo destinato a diventare l'erede del silicio, il grafene. Le applicazioni vanno dall'elettronica alle telecomunicazioni, fino all'energia e ai dispositivi per la biomedicina. 


È la tabella di marcia indicata dal progetto Grafene, uno dei progetti 'bandiera' della Commissione Europea, che prevede l'investimento di un miliardo.

Pubblicato sulla rivista Nanoscale, il piano d'azione per portare sul mercato le invenzioni basate sul grafene è stato preparato da oltre 60 ricercatori e l'Italia è fra i primi Paesi coinvolti nell'iniziativa, con 23 partner rappresentati da Consiglio Nazionale delle Ricerche (Cnr) e Istituto Italiano di Tecnologia (Iit). 

Per il direttore della Flagship Grafene, Jari Kinaret, ''la roadmap rappresenta una base solida per lo sviluppo delle attività di tutta la comunità europea sul grafene nei prossimi anni. Non si tratta di un documento statico, ma evolverà per tenere conto dei progressi raggiunti e delle nuove applicazioni che l'industria identificherà e seguirà".

Sono otto le aree di applicazione identificate come le più interessanti per il mercato europeo: fra queste dispostivi elettronici flessibili, sensori e dispositivi biomedici di nuova generazione, tecnologie per immagazzinare energia.

Entro 3-5 anni potrebbero arrivare i prototipi di nuove celle solari, batterie e supercondensatori, così come nuovi dispositivi per applicazioni mediche e per immagazzinare dati.

Pronti fra 3 anni i primi materiali 'figli' del grafene 02 marzo 2015

In a 200-page open-access paper published in the Royal Society of Chemistry journal Nanoscale ("Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems"), more than 60 academics and industrialists lay out a science and technology roadmap for graphene, related two-dimensional crystals, other 2D materials, and hybrid systems based on a combination of different 2D crystals and other nanomaterials. The roadmap covers the next ten years and beyond, and its objective is to guide the research community and industry toward the development of products based on graphene and related materials.


The European nanotechnology roadmap for graphene Feb 24, 2015


Arriva il silicio '2.0', una nuova 'forma' che ne trasforma alcune proprietà tanto da poter forse aprire la strada ad una nuova elettronica super veloce. Il 'nuovo' silicio sintetizzato da un gruppo di ricercatori coordinato da Timothy Strobel dell'Istituto Carnegie a Washington, il cui lavoro è stato pubblicato su Nature Materials, potrebbe avere moltissime applicazioni, da celle solari molto più efficienti, Led più potenti fino a computer super veloci.


"Siamo ormai arrivati quasi al limite nel migliorare l'efficienza dei dispositivi elettronici a base di silicio - ha spiegato Giampiero De Cesare, ingegnere elettronico all'Università Sapienza di Roma - e questo studio apre la possibilità di fare un salto in più in questa direzione". Il silicio è uno degli elementi più abbondanti del nostro pianeta, il secondo dopo l'ossigeno, e le sue caratteristiche di conducibilità elettrica lo hanno reso essenziale per tutte le tecnologie elettroniche. 

Decenni di ricerche per migliorare le prestazioni del silicio sembrano aver raggiunto dei limiti strutturali e 'spremuto' ogni possibilità offerta da questo materiale. "Proprio per questo - ha proseguito De Cesare - si seguono al momento due strade: il miglioramento delle tradizionali tecnologie a base di silicio, con il vantaggio di proseguire in una strada buona ma difficilmente migliorabile ancora per molto, oppure esplorare il mondo delle nanotecnologie e del grafene".

Proseguendo nel percorso 'tradizionale', i ricercatori statunitensi hanno messo a punto una tecnica per 'purificarlo' e forse permettere un passo in avanti nel suo sfruttamento ulteriore. Si tratta di una nuova forma del silicio - così come il carbonio può essere disposto in modi diversi e formare grafite, diamanti o grafene - realizzata usando altissime pressioni. In questo modo i ricercatori hanno disposto il silicio in reticoli simili alle celle delle api e trasformato alcune proprietà del materiale. 

"Modificando la struttura del silicio - ha proseguito De Cesare - i ricercatori affermano di migliorare alcune proprietà del silicio utili ad esempio a migliorare l'efficienza delle celle fotovoltaiche o per chip per computer ancora più veloci. Si tratta di un lavoro nuovo che potrebbe portare realmente dei benefici ma bisognerà capire nel tempo se questa innovazione avrà costi tali da essere impiegata a livello applicativo". 


Silicon is the second most-abundant element in the earth's crust. When purified, it takes on a diamond structure, which is essential to modern electronic devices -- carbon is to biology as silicon is to technology. Scientists have synthesized an entirely new form of silicon, one that promises even greater future applications.




On the search for high performance materials for applications such as gas storage, thermal insulators or dynamic nanosystems it is essential to understand the thermal behavior of matter down to the molecular level. Classical thermodynamics average over time and over a large number of molecules. Within a three dimensional space single molecules can adopt an almost infinite number of states, making the assessment of individual species nearly impossible.

Now researchers from Technische Universität München (TUM) and Linköping University (LIU) have developed a methodology, which allows to explore equilibrium thermodynamics of single molecules with atomic resolution at appreciable temperatures. The breakthrough study is based on two pillars: a technology which allows to cage molecules within two-dimensional nanopores and extensive computational modelling.

Trapped in two dimensions

At the Chair of Molecular Nanoscience and Chemical Physics of Interfaces at TU München, led by Prof. Dr. Johannes V. Barth, PD Dr. Florian Klappenberger developed the method to produce high-quality metal-organic networks on a silver surface. The network forms nanopores which restrict the freedom of movement of adsorbed single molecules in two-dimensions. Using scanning tunneling microscopy the researchers were able to track their motions at different temperatures with sub-nanometer resolution.

Parallel to the experiments, the researchers worked with sophisticated computer models to describe the temperature dependence of the dynamics of these single trapped molecules. "We have applied state-of-the-art supercomputer calculations to understand the interactions and energy landscape determining the motion of the molecules", says Jonas Björk of Linköping University.

Comparing experimental and modeled data the scientists unraveled that under certain conditions the integral theory approaches a simple projection of the molecular positions in space. This approach is central to statistical mechanics, but has never before been challenged to reproduce an experiment, due to the practically infinite molecular positions and energies one needed to consider without the nanoscale confinement.

Analogy to biology

"It was extremely exciting to employ two-dimensional networks as a confinement strategy to reduce the available conformational space of a single molecule, like a chaperone does with a protein", says Dr. Carlos-Andres Palma, the lead author of the study. "In analogy to biology, such form of confinement technology has the potential to establish sensors, nanomachines and possibly logics controlled by and made of molecular distributions."

Applying their knowledge of characteristic equilibrium configurations, the researchers carefully modulated the nanopore, thus making a single molecule write letters of the alphabet such as L, I and U, just by fine-tuning the temperature.

The research was funded by the European Research Council (ERC Advanced Grant MolArt) and the Swedish Research Council. The Swedish National Supercomputing Center provided supercomputing ressources. The research group of Professor Barth is member of the Catalysis Research Center (CRC) of the TUM.

Publication:

Visualization and thermodynamic encoding of single-molecule partition function projections Carlos-Andres Palma, Jonas Björk, Florian Klappenberger, Emmanuel Arras, Dirk Kühne, Sven Stafström, Johannes V. Barth Nature Communications, Feb 23, 2015 - DOI: 10.1038/ncomms7210

Moving molecule writes letters: Caging of molecules allows investigation of equilibrium thermodynamics Muenchen, Germany | February 27th, 2015


Molecular self-assembly of a foundation rung (FR) labeled with two fluorophores (red and green) (credit: A. Hariri et al./Nature Chemistry)

McGill University researchers have developed a new low-cost method to build DNA nanotubes block by block. It could help pave the way for scaffolds made from DNA strands for applications such as optical and electronic devices or smart drug-delivery systems.
The current method of constructing DNA nanotubes is based on spontaneous assembly of DNA in solution, which is vulnerable to structural flaws.
The new technique, reported Monday Feb. 23 in Nature Chemistry, promises to reduce such flaws and also makes it possible to better control the size and patterns of the DNA structures, the scientists report.
Just like a Tetris game, where we manipulate the game pieces with the aim of creating a horizontal line of several blocks, we can now build long nanotubes block by block,” said Amani Hariri, a PhD student in McGill’s Department of Chemistry and lead author of the study.
“By using a fluorescence microscope we can further visualize the formation of the tubes at each stage of assembly, as each block is tagged with a fluorescent compound that serves as a beacon. We can then count the number of blocks incorporated in each tube as it is constructed.”
This new technique was made possible by the development in recent years of single-molecule microscopy.
That research has enabled scientists to view at the nanoscale by turning the fluorescence of individual molecules on and off. (That groundbreaking work won three U.S.- and German-based scientists the 2014 Nobel Prize in Chemistry.)
The resulting “designer nanotubes” approach promises to be far cheaper to produce on a large scale than those created with DNA origami — another technique for using DNA as a nanoscale construction material — according to Hanadi Sleiman, who co-authored the new study and holds the Canada Research Chair in DNA Nanoscience.
Funding for the research was provided by the Natural Sciences and Engineering Research Council of Canada, the Canada Foundation for Innovation, NanoQuébec, the Canadian Institutes of Health Research, and the Fonds de recherché du QuébecNature et technologies.

Abstract of Stepwise growth of surface-grafted DNA nanotubes visualized at the single-molecule level
DNA nanotubes offer a high aspect ratio and rigidity, attractive attributes for the controlled assembly of hierarchically complex linear arrays. It is highly desirable to control the positioning of rungs along the backbone of the nanotubes, minimize the polydispersity in their manufacture and reduce the building costs. 
We report here a solid-phase synthesis methodology in which, through a cyclic scheme starting from a ‘foundation rung’ specifically bound to the surface, distinct rungs can be incorporated in a predetermined manner. Each rung is orthogonally addressable. 
Using fluorescently tagged rungs, single-molecule fluorescence studies demonstrated the robustness and structural fidelity of the constructs and confirmed the incorporation of the rungs in quantitative yield (>95%) at each step of the cycle. 
Prototype structures that consisted of up to 20 repeat units, about 450 nm in contour length, were constructed. Combined, the solid-phase synthesis strategy described and its visualization through single-molecule spectroscopy show good promise for the production of custom-made DNA nanotubes.

Building customized DNA nanotubes step by step February 24, 2015
































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