General Considerations

 General Considerations

In late 2019, a novel coronavirus emerged, spreading quickly from its origin in China across the globe. The CDCrecommended terminology for the virus is SARS-CoV-2, and the illness caused by this virus is called “Coronavirus Disease 2019” or COVID-19 (https://www.cdc.gov/coronavirus/2019-ncov/summary.html). COVID-19 was declared a pandemic by the WHO on March 11, 2020. The earliest known case in the United States was documented on January 21, 2020, in a man who had recently returned to the state of Washington from China. The first US case that was not associated with travel or contact with infected travelers was identified in February 2020 in Solano, California. As of May 22, 2020, the confirmed number of global cases is over 5.1 million, including more than 333,000 deaths.

ΠΕΡΙΣΣΟΤΕΡΑ ΓΙΑ ΤΟΝ COVID - 19 . (3 ΑΡΧΕΙΑ)

ΠΕΡΙΣΣΟΤΕΡΑ ΓΙΑ ΤΟΝ COVID - 19 . (3 ΑΡΧΕΙΑ) 

1ο ΑΡΧΕΙΟ ( ΠΑΤΗΣΤΕ ΣΤΟΝ ΣΥΝΔΕΣΜΟ ΕΔΩ) 

2ο ΑΡΧΕΙΟ (ΠΑΤΗΣΤΕ ΣΤΟΝ ΣΥΝΔΕΣΜΟ ΕΔΩ)

3ο ΑΡΧΕΙΟ (ΠΑΤΗΣΤΕ ΣΤΟΝ ΣΥΝΔΕΣΜΟ ΕΔΩ)

Severe Acute Respiratory Syndrome—Coronavirus 2019 (SARS-CoV-2)

 Severe Acute Respiratory Syndrome—Coronavirus 2019 (SARS-CoV-2)

ESSENTIALS OF DIAGNOSIS

Wide spectrum of symptoms.

Asymptomatic in at least 20–35%.

Upper respiratory tract illness with fever and cough most often when symptomatic.

The clinical triad of cough, fever, and dyspnea is infrequent (less than 15%).

Advanced pulmonary complications (pneumonia, acute respiratory distress syndrome [ARDS]) with fulminant

disease.

Mortality of 1–21% (the higher for the New York City outbreak).

High predilection for the elderly, the immunocompromised, those with chronic diseases, those living in crowded

conditions.

MEDICAL SOURCES 29/12/2020

When to Admit for corona virus infection covid-19

 When to Admit for coronavirus covid - 19 infection

The principal complications requiring admission are respiratory. Progression to respiratory failure and ARDS can be rapid, and any patient in a high-risk category for complications (advanced age; immunosuppression; chronic diseases, particularly hypertension, obesity, and diabetes) should be admitted for observation and placed under intensive care based on respiratory parameters. Corey BL et al. A strategic approach to COVID-19 vaccine R&D. Science. 2020 May 11. [Epub ahead of print] [PMID: 32393526] JAMA Coronavirus Disease 2019 (COVID 19). https://jamanetwork.com/journals/jama/pages/coronavirus-alert Lancet COVID-19 Resource Centre. https://www.thelancet.com/coronavirus?dgcid=kr_pop-up_tlcoronavirus20

Moore BJB et al. Cytokine release syndrome in severe COVID-19. Science. 2020 May 1;368(6490):473–4. [PMID: 32303591] New England Journal of Medicine-coronavirus (COVID-19). https://www.nejm.org/coronavirus Riphagen S et al. Hyperinflammatory shock in children during COVID-19 outbreak. The Lancet Online. 2020 May 6. Published online. https://doi.org/10.1016/S0140-6736(20)31094-1. Wang Y et al. Remdesivir in adults with severe COVID-19: a randomised, double-blind, placebo-controlled, multicentre trial. Lancet. 2020;395(10236):1569–78. [PMID: 32423584]

medical sources 27/12/2020

ΟΔΗΓΙΕΣ ΤΟΥ ΕΟΔΥ ΓΙΑ ΤΟΝ ΝΕΟ ΚΟΡΩΝΟΙΟ COVID - 19

ΓΙΑ ΝΑ ΔΕΙΤΕ ΤΙΣ ΟΔΗΓΙΕΣ ΤΟΥ ΕΟΔΥ ΓΙΑ ΤΟΝ ΝΕΟ ΚΟΡΩΝΟΙΟ COVID - 19 ΠΑΤΗΣΤΕ ΣΤΟΝ ΣΎΔΝΕΣΜΟ ΕΔΏ 

 

Japan’s Hayabusa 2 mission returns asteroid sample to Earth

08 Dec 2020 Michael Banks

Back with a bang: officials successfully retrieve a 16 kg capsule that it is hoped contains sample from the asteroid Ryugu. (Courtesy: JAXA)

The Japanese space agency, JAXA, has successfully retrieved a 16 kg capsule that is hoped to contain flecks of an asteroid. The capsule landed in Australia’s remote outback following a six-year mission by the $250m Hayabusa 2 mission to retrieve samples from the asteroid Ryugu. Scientists will now study the contents of the capsule to find out about the origin of the asteroid’s organic matter and water and how these are related to life and ocean water on Earth.

 

Silicon-based material with a direct band gap is the Physics World 2020 Breakthrough of the Year

17 Dec 2020 Hamish Johnston

The Physics World 2020 Breakthrough of the Year goes to Elham Fadaly, Alain Dijkstra and Erik Bakkers at Eindhoven University of Technology in the Netherlands, Jens Renè Suckert at Friedrich-Schiller-Universität Jena in Germany and an international team for creating a silicon-based material with a direct band gap that emits light at wavelengths used for optical telecommunications.

Nine other achievements are highly commended in our Top 10 Breakthroughs of 2020.

Silicon sees the light: Elham Fadaly (left) and Alain Dijkstra in their Eindhoven lab. (Courtesy: Sicco van Grieken/SURF)

It is no exaggeration to say that finding a silicon-based material that emits useful light has been the Holy Grail of optoelectronics. Normally, silicon has an indirect electronic band gap, which means that it does not emit light. As a result, silicon must be integrated with other direct-band-gap semiconductor materials to create the optoelectronic devices that supply the pulses of light that drive information on the Internet. While this integration is possible, it is difficult and expensive.

 

Celebrating Black physicists

29 Oct 2020 Margaret Harris

This week is #BlackInPhysics week, a series of events dedicated to celebrating Black physicists and their contributions to the scientific community. In this episode of the podcast, we talk to two of the week’s co-organizers, Ashley Walker and Xandria Quichocho, about what #BlackInPhysics week involves, why it’s needed and what they hope to achieve.

 

Doing physics in the time of COVID-19

28 Apr 2020 James Dacey

Across the world, personal and professional lives have been profoundly affected during the past few months – and scientists are no exception. In this episode of the Physics World Stories podcast, we find out how physics and physicists are adapting to coronavirus-related lockdowns. Among physicists – as with many professions – there is a growing realisation that things are not about to go back to normal anytime soon.

 

A passion for nanotechnology in medicine:  Black in Nanotech Week cofounder Olivia Geneus on inspiring new nanoscientists

03 Dec 2020 Hamish Johnston

The second week in December is Black in Nanotech Week and its co-founder Olivia Geneus is our guest in this episode of the Physics World Weekly podcast. Geneus talks to Margaret Harris about her interest in using nanotechnology to develop new ways of treating cancer, and about the need to highlight the accomplishments of Black scientists in the field of nanotechnology and inspire the next generation of nanoscientists.

 

Planet Nine: is it a planet, a primordial black hole or something else entirely?

17 Jul 2020 James Dacey

Planet Nine is a hypothetical world in the far reaches of our solar system. Proposed in 2016 by Caltech astronomers Mike Brown and Konstantin Batygin, its existence would explain the unusual orbits of certain Kuiper belt objects (KBOs). But are we completely sure that Planet Nine in fact a planet?

A paper in September 2019 suggested the gravitational effects could instead be explained by the presence of a primordial black hole smaller than your fist. To get to the bottom of this mystery, there have been recent proposals to send fleets of tiny probes to the general region of this mysterious object.

 

Could there really be life in the clouds of Venus?

23 Sep 2020 James Dacey

The news last week that scientists had spotted a potential signature of life in the clouds of Venus was always likely to cause a stir. But arriving the middle of the COVID-19 pandemic – during which our everyday lives have changed significantly – the story has truly captured the public imagination. In the latest episode of the Physics World Stories podcast, Andrew Glester takes a broad view of the discovery: an inspiring example of lateral thinking, persistence and collaboration.

 

How capable are today’s quantum computers?

14 Oct 2020 James Dacey

Media coverage of quantum computing often focusses on the long term potential for these devices to leave classical computing in the dust. But what about the rudimentary quantum systems that are already being developed and tested by technology companies? What are the latest advances in the field? And what might these systems realistically be able to achieve in the short to medium term? Andrew Glester investigates these questions in the latest episode of the Physics World Stories podcast.

 

Autonomous cars: potential lifesavers but with new risks

26 Aug 2020 James Dacey

Studies suggest that human error is responsible for over 90% of the 1.25 million people who die each year globally due to car accidents. Therefore, improving driver safety is one of the biggest incentives for increasing the autonomy of vehicles. But this brave new world of autonomous driving is not without its own risks – as Andrew Glester discovers in the August episode of the Physics World Stories podcast.

 

Face shields cannot protect wearers from virus particles carried by vortex rings

16 Dec 2020

Vortex flow: still from a simulation video showing how air from a sneeze can envelope a face shield. (Courtesy: Fujio Akagi/Isao Haraga/Shin-ichi Inage/Kozaburo Akiyoshi)

Vortex rings created when a person sneezes can transport virus particles to the noses of people wearing face shields – according to fluid dynamics simulations done by Fujio Akagi and colleagues at Fukuoka University in Japan. Their research reveals how these complex flows allow air-carried particles to enter the gaps between a shield and its wearer’s face. Their discovery exposes a key weakness in existing protective equipment and could lead to face shield designs that are better at diverting airflows away from wearers.

 

Optical sensor offers non-invasive monitoring of intracranial pressure

   17 Dec 2020 Tami Freeman

A volunteer wearing the non-invasive intracranial pressure sensor. (Courtesy: Panicos Kyriacou)

Traumatic brain injury is a major cause of death and disability. When a patient attends an A&E or neurocritical care unit with a head injury, one of the most important parameters to assess injury severity is intracranial pressure (ICP), as raised ICP is particularly associated with poor outcome. Measuring ICP, however, is currently a highly invasive process.

Speaking at the recent IOP symposium “Optics in Clinical Practice”, Panicos Kyriacou from the Research Centre for Biomedical Engineering at City, University of London described his team’s work in designing a non-invasive optical sensor technology for dynamically measuring ICP.

 

Microtube implosions could produce megatesla magnetic fields

04 Nov 2020 Isabelle Dumé

A microtube implosion. (Credit: M Murakami)

A newly discovered mechanism known as microtube implosion could make it possible to generate magnetic fields 1000 times stronger than any yet seen in the laboratory. According to the researchers who developed it at Japan’s Osaka University, the new method could be used to generate super-strong magnetic fields for fundamental research in fields such as materials science, quantum electrodynamics and astrophysics.

 

Laser ‘speed limit’ leaves defects in 3D-printed parts

10 Dec 2020 Isabelle Dumé

Artwork showing the boundary and origin of keyhole porosity. Credit: Ye Feng and Cang Zhao, Tsinghua University

3D printing techniques are transforming many areas of manufacturing. One such technique, laser powder bed fusion (LPBF), is particularly attractive because it can be used to make complex metal parts that would be difficult or impossible to manufacture conventionally. However, it suffers from a major drawback in the form of tiny voids that weaken and degrade the metal. Researchers in the US and China have now identified how these voids are generated, and how they become trapped as the metal solidifies – findings that could help manufacturers find ways to control them, and thereby improve 3D metal-printing processes.

In LPBF, a high-power laser, guided by a digital computer-aided design and drafting model, is scanned across a thin layer of metal powder.

 

Destructive quantum interference improves single-molecule switch

16 Dec 2020 Isabelle Dumé

Novel type of quantum interference enables single-molecule switch with high on/off ratio. Credit: Julia Greenwald and Suman Gunasekaran/Columbia Engineering

A single-molecule switch that operates via destructive quantum interference has the highest on/off ratio for a device of its kind. The switch, developed by researchers at Columbia University in the US and the University of Glasgow, UK, consists of a molecule six nanometres long (similar in size to the smallest computer chips on the market) and a special central unit. It can carry currents of over 0.1 microamps in its “on” state and could allow for faster, smaller and more energy-efficient transistors.

 

Tiny particles get the panoramic treatment

08 Dec 2020 Isabelle Dumé

A new optical imaging technology to determine the characteristics of nanoparticles as small as 25 nanometres in diameter. (Credit: University of Houston)

A new label-free optical imaging technique based on unscattered light can detect nanoparticles as small as 25 nm in diameter. The technology overcomes several limitations of other advanced methods for imaging tiny particles, and its developers at the University of Houston and the University of Texas M D Anderson Cancer Center in the US say it might be used to study viruses and other structures at the molecular level.

 

China launches sample-return mission to the Moon

24 Nov 2020

Lift-off: Chang’e-5 will attempt to bring back 2 kg of lunar material to study the evolution history of our closest neighbour (Courtesy: CNSA)

China has successfully launched a mission to bring back rocks from the Moon– the first attempt to do so for nearly 45 years. Chang’e-5 was launched at 4:30 a.m. local time today by a Long March 5 rocket from Wenchang Satellite Launch Center. Once it lands on the Moon it is expected to grab up to two kilograms of soil from an area not previously sampled to better understand the evolution history of our closest neighbour.

Chang’e-5, weighing 8.2 tonnes, consists of four parts: an ascender, lander, returner and orbiter. Upon entering the Moon’s orbit, the ascender and lander will separate and touch down in the Mons Rümker region — a volcanic mound in the northwestern part of the Moon’s near side.

 

Little book, big science

16 Dec 2020

Taken from the December 2020 issue of Physics World. Members of the Institute of Physics can enjoy the full issue via the Physics World app.

David Appell reviews The Little Book of Cosmology by Lyman Page

CMB fluctuations Temperature map of the cosmic microwave background. (Courtesy: WMAP Science Team)

In the latter half of the 20th century physicists undertook a shrewd move: they began to take the entire universe as their laboratory. It was a clever manoeuvre based on real-estate values alone, but it had other advantages as well. Floor space was essentially unlimited, maintenance fees were negligible, it cost nothing to heat and cool, and no insurance policies were required. But getting through the door, or even watching through a window, was costly. Of course, astronomers and physicists have always used observations of the universe to hone their understanding of the world.

As Lyman Page – the eminent Princeton University cosmologist – recounts in The Little Book of Cosmology, it was the discovery of the cosmic microwave background (CMB) that started the age of cosmology we’re in now, something that hadn’t much interested astronomers until then.

“We cosmologists,” writes Page, who studies temperature variations in the CMB, near the end of this clearly written, delectable book, “feel fortunate to have been alive in the decades when the explosion of knowledge about the universe took place.”

 

Fundamental constant measured at highest precision yet

15 Dec 2020 Isabelle Dumé

The experimental measurement of the fine-structure constant. © Pierre Cladé, Saïda Guellati-Khélifa and Tatsumi Aoyama

The most precise measurement ever of the fine-structure constant has placed new constraints on theories that predict the existence of “dark sector” particles. The new value, which researchers in France measured using clouds of cold rubidium atoms, provides a stringent test of the Standard Model of particle physics while also further limiting the properties of dark matter – the substance thought to make up more than 90% of the matter in our universe.

The fine-structure constant α is a composite of several physical quantities (including e, the charge on an electron, and c, the speed of light) that, together, characterize the strength of the electromagnetic interaction.

 

Aspiring astronaut and Space Age ambassador

14 Dec 2020

Taken from the December 2020 issue of Physics World. Members of the Institute of Physics can enjoy the full issue via the Physics World app.

Andrew Glester reviews Not Necessarily Rocket Science: a Beginner’s Guide to Life in the Space Age by Kellie Gerardi

Inside view Kellie Gerardi returning from a successful microgravity research flight. (CC BY 4.0 Kellie Gerardi)

When the Apollo 11 astronauts landed on the Moon in 1969 the whole world stopped, just for a moment, and looked up. We stepped out into the universe and firmly entered the Space Age, which had begun with Sputnik just 12 years earlier. For many Physics World readers, the scientific and engineering exploits of those early achievements are a source of intrigue and no little excitement. From those crackled first words on the Moon, to images of the boot print in the lunar surface, or the new perspective of our world – the fragile blue marble suspended in darkness – humanity’s most impressive engineering effort has had a huge impact on our collective consciousness.

Commercial spaceflight industry professional and science communicator Kellie Gerardi was one of the many who wanted to be part of the nascent Space Age. But with a degree in film studies rather than aerospace engineering, her non-traditional path in the space industry is a key theme of her new book Not Necessarily Rocket Science: a Beginner’s Guide to Life in the Space Age. With more than 122,000 followers on Instagram, Gerardi is something of a social-media star, and her book serves as part mission statement, part witness statement and part manifesto.

 

Balloon-borne telescopes could keep cool with less

11 Dec 2020 Isabelle Dumé

In-flight video still from BOBCAT during liquid helium transfer at an altitude of 130,000 feet. Credit: NASA

Balloon-borne telescopes can observe a wealth of astrophysical phenomena that ground-based instruments cannot, but onerous cooling requirements limit how much equipment can be taken aloft. Researchers at NASA’s Goddard Space Flight Center found a way to minimize this problem by drastically reducing the weight of a telescope’s cooling system. The researchers have tested their approach on a mission called the Balloon-Borne Cryogenic Testbed (BOBCAT) and have a follow-up mission planned to study it further.

Distant galaxies and star- and planet-forming clouds of gas and dust emit photons in the infrared region of the spectrum.

 

Ultracold atoms put high-temperature superconductors under the microscope

27 Nov 2020 Margaret Harris

Cool tool A photo of the scanning quantum cryogenic atom microscope, or SQCRAMscope. (Courtesy: Benjamin Lev)

Physicists have deployed a Bose–Einstein condensate (BEC) as a “quantum microscope” to study phase transitions in a high-temperature superconductor. The experiment marks the first time a BEC has been used to probe such a complicated condensed-matter phenomenon, and the results – a solution to a puzzle involving transition temperatures in iron pnictide superconductors – suggest that the technique could help untangle the complex factors that enhance and inhibit high-temperature superconductivity.

 

Fast quantum random number generator could advance cryptography on the cheap

09 Dec 2020

Thumbs-up for randomness David Drahi in the quantum optics lab. (Courtesy: David Drahi)

While world events are often difficult to predict, true randomness is surprisingly hard to find. In recent years, physicists have turned to quantum mechanics for a solution, using the inherently unpredictable behavior of photons to generate the truly random numbers that underpin many modern cryptographic protocols. Now, a new study promises to make this process of quantum random number generation more accessible, by showing that it is possible to produce certifiably random numbers quickly using a system built with off-the-shelf components.

When numbers are used to securely encode information, the randomness of those numbers is crucial: a string of truly random numbers is one that a hacker can never guess.

 

Therapeutics firms share inaugural prize for health physics

21 Jul 2020 Margaret Harris

Microfluidics maestro: Cellular Highways chief executive Samson Rogers poses with a prototype of the company's first commercial sell-sorting instrument. (Courtesy: Cellular Highways)

Companies that use physics to unlock next-generation drugs for respiratory disorders and enable advanced cancer treatments are the first recipients of a new award for early-stage companies in healthcare and medicine. Nebu~Flow, a University of Glasgow spin-out that is commercializing an acoustic nebulizer, and Cellular Highways, a Cambridge-based start-up that develops microfluidic devices for use in cell therapies, each received the inaugural Lee Lucas Award and £5000 in prize money as part of the annual Business Awards presented by the Institute of Physics (IOP).

Speaking on 15 July at the first of two webinars dedicated to the 2020 Business Awards, IOP vice-president for business James McKenzie praised Cellular Highways, Nebu~Flow and 11 other award-winning companies for their work in bringing physics-based products to the market.

 

Magnetic illusion’ can create magnetic fields at a distance

04 Dec 2020

Magnetic illusion: a long wire surrounded by a magnetic replicator generates a replica of the wire outside it. (Courtesy: Phys. Rev. Lett. 10.1103/PhysRevLett.125.177204)

Physicists in the UK and Spain claim that they have found a way to generate and manipulate magnetic fields at a distance. This opens up the possibility of projecting magnetic fields into inaccessible spaces and enables the remote cancellation of magnetic sources, the researchers say. One application of this technique could be improving the control of magnetic microbots and nanoparticles within the human body, for medical applications such as drug delivery and magnetic hyperthermia therapies.

In recent years, metamaterials have enabled scientists to manipulate magnetic fields in unexpected ways, such as creating a magnetic cloak that can make an object magnetically undetectable and magnetic wormholes, which transport a magnetic field from one point in space to another.

 

Sound waves in fermionic superfluid are studied in a ‘beautiful’ experiment

05 Dec 2020

Good vibrations: artist’s concept of sound being transmitted in a fermionic superfluid. (Courtesy: Christine Daniloff/MIT)

The acoustic properties of an ultracold fermion gas have been measured either side of the superfluid transition temperature in an experiment that has been described as “near perfect” and “beautiful”. The results could have significant implications for understanding everything from superconductors to the aftermath of the Big Bang.

Superfluidity occurs at very low temperatures when bosons such as helium-4 form a single, macroscopic quantum ground state. As well as being able to flow indefinitely without losing kinetic energy, a superfluid can famously climb uphill over a barrier to reach an energy minimum. Some fermions such as helium-3 can also form a superfluid by first pairing up to form bosons.

The European Spallation Source: an overview: Cryogenics makes the European Spallation Source a hot property in neutron science

 

Cryogenics makes the European Spallation Source a hot property in neutron science

06 Jul 2020

Cryogenics is a core enabling technology at the European Spallation Source, a next-generation neutron-science facility under construction in Sweden. Joe McEntee talks to John G Weisend II, group leader for specialized technical services at ESS, about the secrets of success at ultralow temperatures

Big science: an aerial view over the ESS construction site in Lund, Sweden, taken in February 2020. (Courtesy: Perry Nordeng/ESS)

Large-scale neutron facilities – one of the mainstays of Europe’s “big science” infrastructure – are routinely used by researchers to understand material properties on the atomic scale, spurring advances across a spectrum of scientific discovery – from clean energy and environmental technology to pharma and healthcare, from structural biology and nanotech to food science and cultural heritage. Industry users, meanwhile, use neutrons to probe deep into engineering components, gaining unique insights into the stresses and strains that affect turbine blades, gas pipelines, fuel cells and the like.

Big science, of course, keeps thinking bigger – and neutron science is no exception. For the neutron user community, in fact, a decade of revolution rather than evolution is hoving into view as construction progresses on the European Spallation Source (ESS), a €1.84bn accelerator-driven neutron source in Lund, Sweden.

 

Physicists fine tune chemical reaction rates for ultracold molecules

12 Dec 2020

Ultracold reactions: shadows of atoms trapped in layers of an optical lattice, before they are paired into ultracold potassium-rubidium molecules. (Courtesy: Ye Group/JILA)

A new technique to cool reactive molecules to temperatures low enough to achieve quantum degeneracy – something not generally possible before – has been created by researchers in the US. In this temperature regime, the dominance of quantum effects over thermal fluctuations should allow researchers to study new quantum properties of molecules. As a first example, the researchers demonstrated how a slight change in applied electric field can alter the reaction rate between molecules by three orders of magnitude.

 

DNA origami makes 3D superconducting nanostructures

25 Nov 2020 Isabelle Dumé

Highly nanostructured 3D superconducting materials can be created based on DNA self-assembly. Credit: Brookhaven National Laboratory

Researchers in the US and Israel have developed a way to make 3D superconducting nanostructures by combining DNA with niobium and silicon. This new technique might be used to make signal amplifiers that enhance the speed and accuracy of quantum computers as well as ultrasensitive magnetic field sensors for medical and geophysics applications.

While traditional nanofabrication techniques like electron-beam lithography can produce one-dimensional and two-dimensional superconducting nanostructures, their ability to produce three-dimensional structures is limited.

 

New family of quasiparticles appears in graphene

30 Nov 2020 Isabelle Dumé

Telltale traces Horizontal yellow streaks show Brown-Zak fermions propagating along straight trajectories with high mobility (low resistance). Courtesy: J Barrier

Researchers at the University of Manchester in the UK have identified a new family of quasiparticles in superlattices made from graphene sandwiched between two slabs of boron nitride. The work is important for fundamental studies of condensed-matter physics and could also lead to the development of improved transistors capable of operating at higher frequencies.

In recent years, physicists and materials scientists have been studying ways to use the weak (van der Waals) coupling between atomically thin layers of different crystals to create new materials in which electronic properties can be manipulated without chemical doping. The most famous example is graphene (a sheet of carbon just one atom thick) encapsulated between another 2D material, hexagonal boron nitride (hBN), which has a similar lattice constant.

 

New fuel gauge for spacecraft could keep satellites active for longer

06 Dec 2020 Isabelle Dumé

Fuel gauges with higher accuracy could help ensure that satellites stay operational for longer and more is made of their time in orbit. (Credit: NASA Jet Propulsion Laboratory)

When a spacecraft launches, it uses roughly 75–90% of its propellant getting into orbit. The remaining fraction determines how long it can remain up there, but gauging how much fuel is left in the tank is no easy task in zero gravity. Researchers at the US National Institute of Standards and Technology have now developed a solution based on a suite of sensors that detects the capacitance of liquid inside a spacecraft’s fuel tank and uses these data to reconstruct a three-dimensional picture of the remaining fuel.

 

Neutron-rich tantalum offers a view of how heavy elements are forged

01 Dec 2020

Element forge: Hubble Space Telescope image of the remnant of the core collapse supernova SN 1987A, which appeared in the Large Magellanic Cloud in 1987. (Courtesy: NASA/ESA/P Challis and R Kirshner (Harvard-Smithsonian Center for Astrophysics))

A beam of neutron-rich tantalum ions has been created for the first time by an international team of physicists working at RIKEN’s KEK Isotope Separation Facility (KISS) in Japan. The feat was achieved by Philip Walker at the University of Surrey and colleagues, who used state-of-the-art isotope separation techniques to isolate and study the ions. Their research could soon shed new light on how nuclear processes in dying stars create the heavy elements we observe in the universe today.

Rapid neutron capture, also known as the “r-process”, is a series of nuclear reactions that astrophysicists believe is responsible for about half of the elements heavier than iron in the universe.

 

MRI during treatment could improve paediatric proton therapy

10 Dec 2020

Sahaja Acharya and colleagues are investigating the potential role of MRI-guided proton therapy in the treatment of paediatric patients. (Courtesy: Seth Dixon/St. Jude Children’s Research Hospital)

Identifying anatomic changes shown on MRI scans during a course of pencil-beam proton therapy, and adapting treatment plans accordingly, could improve the treatment quality, effectiveness and safety. In a retrospective study, researchers at St. Jude Children’s Research Hospital determined that 27% of paediatric patients, the majority with brain tumours, would have benefited from mid-treatment plan changes.

 

Nanoparticle sensitizers could enhance radiotherapy effectiveness

08 Dec 2020 Tami Freeman

MR images showing uptake of AGuIX nanoparticles in brain metastases for two patients in the NANO-RAD1 study. The far-right images show 3D colour-coded reconstructions of metastases containing AGuIX. (Courtesy: Camille Verry)

Radiotherapy plays an essential role in the management of cancer, but unwanted irradiation of healthy tissues can lead to adverse side effects and limit the deliverable tumour dose. Radiosensitizers, which preferentially sensitize tumour cells to irradiation, can increase the therapeutic window and enable higher target doses without increasing normal tissue damage.

One approach under investigation to improve the effectiveness of radiotherapy is the use of nanoparticles as radiosensitizers. And at the recent ESTRO 2020 congress, attendees heard about some of the latest developments and clinical studies in this field.

ΟΔΗΓΙΕΣ ΓΙΑ ΤΗΝ ΕΠΙΛΥΣΗ ΠΡΟΒΛΗΜΑΤΩΝ ΣΤΗΝ ΦΥΣΙΚΗ – ΓΕΝΙΚΟΤΕΡΗ ΜΕΘΟΔΟΛΟΓΙΑ

 ΟΔΗΓΙΕΣ ΓΙΑ ΤΗΝ ΕΠΙΛΥΣΗ ΠΡΟΒΛΗΜΑΤΩΝ ΣΤΗΝ ΦΥΣΙΚΗ – ΓΕΝΙΚΟΤΕΡΗ ΜΕΘΟΔΟΛΟΓΙΑ 

Τα τρία στάδια της διαδικασίας επίλυσης προβλημάτων φυσικής που χρησιμοποιούνται γενικά είναι τα εξής: 

• Στρατηγική: Προσδιορίστε ποιες φυσικές αρχές εμπλέκονται και αναπτύξτε μια στρατηγική για τη χρήση τους για την επίλυση του προβλήματος.

 • Λύση: Κάνετε τα μαθηματικά απαραίτητα για να αποκτήσετε μια αριθμητική λύση με μονάδες.

 • Σημασία: Ελέγξτε τη λύση για να βεβαιωθείτε ότι έχει νόημα (σωστές μονάδες, λογικό μέγεθος και πρόσημο) και εκτιμήστε τη σημασία της. 

ΟΙ ΟΔΗΓΙΕΣ ΓΙΑ ΤΑ ΠΡΟΒΛΗΜΑΤΑ ΦΥΣΙΚΗΣ 

Οι δεξιότητες επίλυσης προβλημάτων είναι σαφώς απαραίτητες για την επιτυχία σε ένα ποσοτικό μάθημα σαν την φυσική. Το πιο σημαντικό, η ικανότητα. Η εφαρμογή ευρέων φυσικών αρχών - που συνήθως αντιπροσωπεύονται από εξισώσεις - σε συγκεκριμένες καταστάσεις απαιτούν ένα ευρύ φάσμα γνώσης. Αυτό είναι κάτι πολύ πιο ισχυρό από την απομνημόνευση μιας λίστας γεγονότων. Οι αναλυτικές δεξιότητες και οι ικανότητες επίλυσης προβλημάτων μπορεί να εφαρμόζονται σε νέες καταστάσεις, ενώ ένας κατάλογος γεγονότων δεν μπορεί να δημιουργηθεί αρκετά για να περιέχει κάθε πιθανή περίσταση.