Este aplicabil unei game largi de nanomateriale, Inclusiv particule, fibre, pulberi, tuburi și fire precum și agregate și aglomeratului, și recunoaște incertitudinea anterioare și actuale în dezvoltarea de gestionare eficientă a riscurilor În cazul în care se ocupă cu nanomaterialele și pledează pentru o strategie de precauție pentru a minimiza potențialul expunere.
Posted: May 30, 2016
NanoSafety Group publishes 2nd Edition of guidance to support safe working with nanomaterials
(Nanowerk News) The UK Nanosafety Group (UKNSG) has updated and published a 2nd edition of guidance (pdf) to support safe and responsible working practices with nanomaterials in research and development laboratories.
The document aims to provide guidance on factors relating to establishing a safe workplace and good safety practice when working with particulate nanomaterials.It is applicable to a wide range of nanomaterials, including particles, fibres, powders, tubes and wires as well as aggregates and agglomerates, and recognises previous and current uncertainty in developing effective risk management when dealing with nanomaterials and advocates a precautionary strategy to minimise potential exposure.
The 2nd edition of the guidance provides updates to account for changes in legislation, recent studies in the literature, and best practice since 2012.
In particular, specific sections have been revised to account for the full implementation of Global Harmonised System (GHS) which came into force on 1 June 2015 through the CLP regulations. The document explains the approaches that are presently being used to select effective control measures for the management of nanomaterials, more specifically control banding tools presently in use. Significant changes can be found in the following sections: ‘Hazard Banding’, ‘Exposure Control’, ‘Toxicology’, and ‘Monitoring’.
Of relevance to employers, managers, health and safety advisors, and users of particulate nanomaterials in research and development, the guidance should be read in conjunction with the Approved Code of Practice on COSHH, together with the other literature referred to in the document.
The document has been produced taking account of the safety information currently available and is presented in the format of guidance and recommendations to support implementation of suitable protocols and control measures by employers and employees. It is intended that the document will be reviewed and updated on a periodic basis to keep abreast of the evolving nature of the content.
De zeci de ani, inginerii biomedicale au fost încapsularea cu migală de proteine în nanoparticule pentru a controla eliberarea lor. Acum, o echipa de cercetare condusa de profesorul universitar Molly Shoichet a demonstrat a proteinelor poate fi lansat peste cateva saptamani, chiar luni, fără a mai fi încapsulate. În acest caz, echipa de analizat în mod special proteine terapeutice relevante pentru regenerarea tesutului dupa accident vascular cerebral și leziuni ale măduvei spinării.
Researchers control protein release from nanoparticles without encapsulation
(Nanowerk News) A University of Toronto Engineering team has designed a simpler way to keep therapeutic proteins where they are needed for long periods of time. The discovery is a potential game-changer for the treatment of chronic illnesses or injuries that often require multiple injections or daily pills.
For decades, biomedical engineers have been painstakingly encapsulating proteins in nanoparticles to control their release. Now, a research team led by University Professor Molly Shoichet has shown that proteins can be released over several weeks, even months, without ever being encapsulated. In this case the team looked specifically at therapeutic proteins relevant to tissue regeneration after stroke and spinal cord injury.
„It was such a surprising and unexpected discovery,” said co-lead author Dr. Irja Elliott Donaghue, who first found that the therapeutic protein NT3, a factor that promotes the growth of nerve cells, was slowly released when just mixed into a Jello-like substance that also contained nanoparticles. „Our first thought was, ‘What could be happening to cause this?'”
Left to right: Irja Elliott Donaghue, Malgosia Pakulska and Jaclyn Obermeyer, under the direction of Professor Molly Shoichet in U of T Engineering, discovered that proteins can be released slowly without first encapsulating them in nanoparticles.
Proteins hold enormous promise to treat chronic conditions and irreversible injuries – for example, human growth hormone is encapsulated in these tiny polymeric particles, and used to treat children with stunted growth. In order to avoid repeated injections or daily pills, researchers use complicated strategies both to deliver proteins to their site of action, and to ensure they’re released over a long enough period of time to have a beneficial effect.
This has long been a major challenge for protein-based therapies, especially because proteins are large and often fragile molecules. Until now, investigators have been treating proteins the same way as small drug molecules and encapsulating them in polymeric nanoparticles, often made of a material called poly(lactic-co-glycolic acid) or PLGA.
As the nanoparticles break down, the drug molecules escape. The same process is true for proteins; however, the encapsulating process itself often damages or denatures some of the encapsulated proteins, rendering them useless for treatment. Skipping encapsulation altogether means fewer denatured proteins, making for more consistent protein therapeutics that are easier to make and store.
„This is really exciting from a translational perspective,” said Jaclyn Obermeyer. „Having a simpler, more reliable fabrication process leaves less room for complications with scale-up for clinical use.”
„We think that this could speed up the path for protein-based drugs to get to the clinic,” said Elliott Donaghue.
The mechanism for this encapsulation-free controlled release is surprisingly elegant. Shoichet’s group mixes the proteins and nanoparticles in a Jello-like substance called a hydrogel, which keeps them localized when injected at the site of injury. The positively charged proteins and negatively charged nanoparticles naturally stick together. As the nanoparticles break down they make the solution more acidic, weakening the attraction and letting the proteins break free.
„We are particularly excited to show long-term, controlled protein release by simply controlling the electrostatic interactions between proteins and polymeric nanobeads,” said Shoichet. „By manipulating the pH of the solution, the size and number of nanoparticles, we can control release of bioactive proteins. This has already changed and simplified the protein release strategies that we are pursuing in pre-clinical models of disease in the brain and spinal cord.”
„We’ve learned how to control this simple phenomena,” Pakulska said. „Our next question is whether we can do the opposite–design a similar release system for positively charged nanoparticles and negatively charged proteins.”
Ideea propusă de echipa de cercetători arată modul de abordare a problemelor numărului partiționarea prin aplicarea unei strategii cunoscut sub numele de „recoacere cuantică“. Acest lucru se face prin aplicarea unui câmp magnetic puternic INITIALLY Toate care este apoi oprit lent în timpul simulării. În acest fel, starea cuantică este deformată până când se potrivește cu soluția dorită. Acest lucru poate fi mai rapid decât alte metode pentru a rezolva pe problemă.
Posted: May 27, 2016
Spin glass physics with trapped ions
(Nanowerk News) One of the most striking discoveries of quantum information theory is the existence of problems that can be solved in a more efficient way with quantum resources than with any known classical algorithm.
Number-partitioning, which refers to the simple task of dividing a set of numbers into two groups of equal sums is, in fact, a very difficult problem to solve with classical computers.
Often, such problems can be related to a physical model, which then allows for solving the problem by finding the minimum energy state of the model. Here, an important role is played by spin glass models, that is, models describing a collection of tiny magnets interacting with each other in a random fashion.
Solving Number partitioning with spin glass models. (Image: ICFO)
In the recent work published in Nature Communications („Quantum annealing for the number-partitioning problem using a tunable spin glass of ions”), Dr. Tobias Grass, David Raventós, Dr. Christian Gogolin, led by ICREA Prof. at ICFO Dr. Maciej Lewenstein, in collaboration with Dr. Bruno Julià-Díaz from the University of Barcelona (UB), lay the theoretical foundations for a quantum simulation of spin glass physics with trapped ions.
The idea proposed by the team of researchers shows how to tackle the problem of number partitioning by applying a strategy known as „quantum annealing”. This is done by initially applying a strong magnetic field which is then switched off slowly during the simulation. In this way, the quantum state is deformed until it matches with the desired solution. This can be faster than other methods to solve the problem.
The implementation of this approach is possible with state-of-the-art techniques for trapping, cooling, and manipulating ions. As Dr. Grass clearly states, „In the past, we have seen quantum simulations which solve a problem from quantum physics. In our approach, the same techniques are used to solve a problem from computer science. The results of our study opens a new path and brings us a step closer to the development of a quantum computer.”
Dacă ați uitat vreodată telefonul sau l-ați lăsat acasă pentru această zi, ați realizat cât de mult îl utilizați
Mulți oameni cred în mod greșit că furnizorii lor de servicii mobile ar trebui să implementeze mecanisme de protecție cibernetică pentru utilizatorii lor
Tehnologia inteligentă de la domiciliu a fost mult timp bătută la ușă va intra în mainstream după ce gadget-urile rivale și serviciile vor deveni indiscutabile oaspeți care se vor alătura unul cu altul, spun cei din industrie
Cercetătorii de la Mason care lucrează la următorul pas în lupta împotriva hackerilor de pe computer. Este o metodă numită „shuffling”, în care hackerii și utilizatorii obișnuiți sunt rapid separați printr-o serie de împărțiri care în cele din urmă izolează actorii răi
Orice sistem în echilibru termodinamic este cunoscut pentru a satisface tranzițiile perfect echilibrate înainte și înapoi între oricare două state. Este deci imposibil, de exemplu, de a conduce o moară de vânt pentru a face de lucru prin utilizarea numai fluctuațiile termice. Noi cercetari arata modul în care sistemele de viață încalcă acest principiu. Astfel, chiar și fluctuațiile stocastice în căutarea sistemelor vii ar putea fi folosite pentru a conduce căutarea o moară de vânt la scară mică.
Acum, oamenii de stiinta de la MIT, Universitatea din Gottingen, Ludwig Maximilians Universitatea din Munchen, Universitatea Amsterdam liber, și Universitatea Yale au dezvoltat o tehnica de analiză a datelor neinvaziv a facut poate discerne daca al obiectului de mișcare aleatoare este condus în mod activ sau termic. După urmărirea conformații sau locațiile au o structură în interiorul celulei sau o particulă trece prin așa cum se mișcă, și observând modul în care particula tranzițiile înainte și înapoi între statele de căutare, cercetatorii aplica un principiu fundamental al fizicii statistice la mina determinist Fie mișcările aleatorii activ sau Therma
Posted: Apr 29, 2016
New technique spots active motion in cells
(Nanowerk News) Inside every living cell, internal structures are continuously moving about. Under a microscope, organelles such as the nucleus, mitochondria, transport vesicles, or even external flagella wobble and twitch. This may happen spontaneously as these tiny structures are passively jostled inside a cell. But that’s not necessarily all there is to it. Often a cell invests extra energy into these motions to enhance cell functions in ways we don’t yet understand.
At the microscopic scale, particles in a fluid or a gas can move about in response to bombardment by the surrounding molecules. Such passive, thermally-induced motions are often very hard to distinguish from actively driven movements, and it can be impossible to tell just by looking whether particular motions inside a cell are simply thermal or pushed by some extra input of energy.
Any system in thermodynamic equilibrium is known to satisfy perfectly balanced forward and backward transitions between any two states. It is therefore impossible, for instance, to drive a windmill to do work by using only thermal fluctuations. The new research shows how living systems violate this principle. Thus, even stochastic fluctuations in such living systems could be used to drive such a small-scale windmill.
Now scientists at MIT, the University of Göttingen, Ludwig Maximilians University of Munich, the Free University Amsterdam, and Yale University have developed a noninvasive data analysis technique that can discern whether an object’s random motion is actively or thermally driven. After tracking the conformations or locations that a structure within the cell or a particle passes through as it moves, and observing how the particle transitions back and forth between such states, the researchers apply a fundamental principle of statistical physics to determine whether the random motions are active or thermal.
Nikta Fakhri, assistant professor in MIT’s Department of Physics, says the results will help scientists to uncover “hidden” active processes that drive a cell’s constituents to move in seemingly random ways.
“We want to see if particular dynamics in living systems — be those cells or tissues or whole organisms — that look at first glance like random thermal motion are indeed actively driven,” says Fakhri, who is a first co-author on the paper. “This is important because there must be a vital function connected with the process if the cell spends energy on it. Our work provides a practical experimental method to identify active, nonequilibrium processes in observations of biological systems.”
Fakhri and her colleagues have published their results today in the journal Science („Nikta Fakhri”).
Researchers at MIT and elsewhere have developed a noninvasive technique that distinguishes active from passive fluctuations inside cells. (Video: Melanie Gonick/MIT)
Shaking things up
Observations of the movements of microscopic particles date back to 1827, when Scottish botanist Robert Brown was looking through a microscope at pollen grains in water. He noticed that the grains contained tiny particles that jiggled vigorously, and at first glance believed that their motion meant the particles were somehow alive and moving on their own. Eventually, Brown retired this theory when he observed the same jiggling with inert particles from rocks, realizing that just seeing a particle moving doesn’t necessarily mean it is alive.
Scientists now know that such particles are being pushed around by even smaller water molecules, which themselves are jiggling. At elevated temperatures, water molecules possess kinetic energy and can remain forever restless. At microscopic scales, these tiny molecules and atoms can “bombard” other much larger particles. This phenomenon is now known as Brownian motion. Scientists today are so used to seeing Brownian motion that they often assume that a particle moving in a random fashion is likely to be at thermal equilibrium — a state in which a system is not dissipating any energy, and therefore inanimate.
In living cells, of course, many organelles or particles tend to move in a “ballistic” fashion, traveling across some distance, with a clearly directed or oscillatory trajectory. These types of motions, Fakhri says, represent an animated state that must be out of equilibrium, requiring a system to expend energy. What is interesting, however, are situations where particles jiggle randomly and seem to be in equilibrium, but in reality move actively.
Frame by frame
Fakhri and her colleagues set out to develop a statistical physics technique that would enable them to tell, just by imaging a particle, whether its random motions are thermal or active in nature.
Using video microscopy, they studied, frame by frame, the oscillatory motion of the flagellum of a Chlamydomonas algae. They deconstructed the backbone of the flagellum into a series of shapes, thus creating a phase space of the states the flagellum passes through as it completes an oscillatory cycle. They then counted the transitions between states. In thermal equilibrium, the back-and-forth transitions between all states must be balanced. However, they observed a clear imbalance in these transitions, confirming the already known fact that the flagellum expends energy for this active oscillatory motion.
Next, they analyzed the motions of a kidney cell’s cilium — an antenna-like appendage that at first glance appears to be jiggling back and forth passively. By tracking the cilium’s orientation and curvature, and counting transitions between states, they observed a slight imbalance in the transitions, pointing to an unexpected active process that drives the cilium, despite its passive appearance.
“This is a great paper, and somewhat a proof of principle,” says Gavin Crooks, senior scientist at Lawrence Berkeley National Laboratory. “Their method has the potential to be applicable to lots of cellular processes — we’ll get deeper insights into the flow of information and energy through the cell, and what makes these molecule machines tick. You could imagine using these methods to examine if a piece of cellular machinery is working the way that it’s meant to.”
Fakhri says the new method will help scientists to uncover new ways in which cells dissipate energy — which, ultimately, is the key to sustaining life. After all, as the Austrian physicist Erwin Schrödinger noted, “Living matter evades the decay to thermal equilibrium.”
“Almost a century later, through the work of this collaboration, we can now go further and find out how cells budget their energy and particularly why they often expend a lot of energy to create these apparently random motions,” Fakhri says.
Tehnologiile informaționale viitoare shoulderstand folosesc în mod considerabil mai puțină energie pentru procesarea datelor. O clasă de materiale interesante pentru acest izolatori topologice cuprinde. Izolatori topologice se disting prin electronii lor la suprafata fiind extrem de mobil, în timp ce materialul este în vrac într-un izolator și nu se efectuează. Deci, din moment ce electronii Simultan transporta un moment magnetic (rotire), izolatori topologice s-ar putea face, prin urmare componente „spintronice“ fezabilă. Componentele spintronice nu ar trebui să se bazeze pe mișcarea purtătorilor de sarcină cum ar fi electroni (ca în componente semiconductoare), ci pe transportul sau manipularea lor rotiri. Acest lucru ar necesita considerabil mai puțină energie.
Posted: Apr 29, 2016
Spintronics for future information technologies
(Nanowerk News) Researchers have demonstrated that this class of materials is suitable for data processing based on spin. The work has been published in the renowned periodical Physical Review B and was selected as „Editor’s Suggestion” article („Ultrafast spin-polarization control of Dirac fermions in topological insulators”).
The illustration depicts the characteristic spin orientation (arrows) of electrons in a topological insulator (below). Using an initial circular polarised laser pulse, the spins are excited and point up or down. This can be proven by a second linearly polarised laser pulse (above). (Image: HZB)
Future information technologies should employ considerably less energy for processing data. One exciting class of materials for this comprises topological insulators. Topological insulators are distinguished by their electrons at the surface being extremely mobile, while the bulk material within is an insulator and does not conduct. Since electrons also simultaneously carry a magnetic moment (spin), topological insulators might also make „spintronic” components feasible. Spintronic components would not be based on the movement of charge carriers like electrons (as in semiconductor components), but instead on the transport or manipulation of their spins. This would require considerably less energy.
An international team headed by HZB physicist Jaime Sánchez-Barriga has now shown how the spins of the electrons in topological insulators can be controlled. The team investigated samples of antimony-telluride, a topological insulator, using circularly polarised laser light. They were able to initiate and direct currents of electrons whose spins were oriented in parallel (i. e., spin-polarised currents) using the „rotational direction” of the laser light. In addition, they were successful in changing the orientation of the spins as well. The team was made up of experimentalists from the Max Born Institute in Berlin and Lomonossow University Moscow, together with theoreticians from Ludwig-Maximilians-Universität München (LMU).
„If you were to utilise magnetically doped topological insulators, you could also probably store this spin information”, explains Oliver Rader, who heads the research group for green spintronics at HZB. „To investigate this however, and also be able to explore the dynamic behaviour of the magnetic moments in particular, ultra-short light pulses in the soft X-ray region are needed. These kinds of experiments can become standard with the planned upgrade of the BESSY II synchrotron source to BESSY-VSR”, he hopes.
Source: Helmholtz-Zentrum Berlin für Materialien und Energie
continuare a testelor electronice, precum și a testelor de uzură și spălare.
Materialele senzorilor care vin în folosință sunt flexibile, transparente și potrivite pentru diferite aplicații, alături de textile inteligente: Înregistrează presiune și deformare și pot astfel să funcționeze ca senzori de atingere sau mișcare. Sensibilitatea acestora la abaterile de temperatură permite în continuare monitorizarea schimbărilor de temperatură sau a interacțiunii fără contact, de exemplu ca senzori de proximitate.Senzorii din îmbrăcămintea funcțională ar putea ajuta la optimizarea exercițiilor prin monitorizarea secvențelor de mișcare. Un nou material senzor transparent, dezvoltat de Fraunhofer ISC, permite detectarea senzorilor de măsurare a mișcării pe textile. Materialul inovativ va fi prezentat pe IDTechEX Europe la standul F16 din Estrel Berlin, în zilele de 27 și 28 aprilie 2016.
Posted: Apr 21, 2016
Smart printed sensors monitor movement sequences
(Nanowerk News) Wearable technology has caught on to progress health and fitness. Simply worn on the body, smart garments can, for instance, track activity. Sensors in functional clothing could also help optimize exercises by monitoring movement sequences. A novel transparent sensor material developed by Fraunhofer ISC enables movement measuring sensors to be printed onto textiles. The innovative material will be presented on IDTechEX Europe at booth F16 in the Estrel Berlin on 27 and 28 April 2016.
Transparent printed sensors. (Image: K. Selsam-Geißler, Fraunhofer ISC)
Accessories like smart bracelets or smart watches are trending as »personal health coaches«, prompting the bearer to provide for sufficient sleep and activity or a healthy diet. Sensor-embedded textile solutions are a far more challenging and also more expensive approach. Often, function will override appearance. The new materials developed by Fraunhofer ISC might offer a cost-efficient alternative with the extra benefit of more adjustable appearance options.
In cooperation with Fraunhofer ISIT and with support of the project partners from the industry, the new sensor technology will be incorporated into a prototype shirt. This so-called MONI shirt will feature a number of functions but is foremost designed to monitor movement sequences. In an initial step, Fraunhofer ISC has developed novel piezoelectric polymer sensor printing pastes free from toxic solvents while Fraunhofer ISIT has provided the evaluation electronics. The next development steps are planned in close dialogue with the industry partners. They will include field tests on several types of textiles and applications, the further optimization of the electronics as well as wear and washability tests.
The sensor materials coming to use are flexible, transparent and suitable for various applications also beside of smart textiles: They register pressure and deformation and can thus serve as touch or motion sensors. Their sensitivity to temperature deviations further enables monitoring of temperature changes or non-contact interaction, e. g. as proximity sensors.
Non-transparent printed sensors. (Image: K. Selsam-Geißler, Fraunhofer ISC)
A simple screen printing process is all it takes to apply the sensor pastes onto textile fabrics or plastic films. Manufacturing encompasses two steps: First, the pattern is printed. Then, the sensors are subjected to an electric field making the piezolectric polymers align to adopt the targeted pressure sensitivity. The cost-efficient screen printing process is a definite plus when it comes to industrial use. It is the key to mass production of printed sensors on textiles.
Thanks to its transparency and flexibility, the new sensor material offers freedom of design in color and form for textiles and garments. As the sensors are much thinner than a human hair and applicable in whatever form, the wearer will hardly notice them embedded in a garment. There’s yet another benefit: the sensors do not require any power source like a battery. Instead, they harvest energy.
Smart textiles like this could be employed in health care or assisted living. In eldercare, everyday life movement sequences could be monitored and failure noticed. Additionally, it would be possible to monitor body signals of in-patients, such as temperature or breathing. This could be especially beneficial for bedridden patients or babies. Some day, even heart rate surveillance may be possible. Last but not least, functional sensor clothing could achieve cost reductions in the health care system. On top of assuming patient monitoring functions it could add to preventive health care.
In Addition to printed sensors on textiles Fraunhofer ISC shows textilintegrated pressure sensors made of silicone e. g. to measure pressure in shoes.
Au fost arătate două metode de salvare a vieților: construirea de clădiri care protejează cutremurele și instalarea unor sisteme care să emită o alarmă când un cutremur loveste, dând oamenilor mai departe de epicentrul de câteva secunde avertizând
