physicsworld--2020-10-19--Physics in the pandemic: ‘Our physics and dosimetry facilities were vacated for COVID-19 patients’ -

Physics in the pandemic: ‘Our physics and dosimetry facilities were vacated for COVID-19 patients’ - Physics World

Priya Saini is a medical physicist in the radiological physics department of SMS Medical College and Hospitals in Jaipur , India .
This post is part of a series on how the COVID-19 pandemic is affecting the personal and professional lives of physicists around the world .
If you ’ d like to share your own perspective , please contact us at pwld @ ioppublishing.org .
India reported its first case of COVID-19 infection on 30 January 2020 , and currently has the largest number of confirmed cases in Asia .
The first case in the state of Rajasthan was @ @ @ @ @ @ @ .
Since then , the SMS Medical College and Hospitals in Jaipur has served as the main COVID-19 treatment centre in Rajasthan .
The hospital established a fully equipped outpatient department and isolation wards , as well as procuring a number of new X-ray machines and mobile X-ray units for diagnosis and treatment evaluation of COVID-19 patients .
As part of this transition , with the exception of the radiation delivery facility and a small intensive care unit for cancer patients , all other radiotherapy and radiological physics facilities were utilized for COVID-19 @ @ @ @ @ @ @ end-March , there were four medical physicists in the hospital ( two of whom were in vulnerable groups ) .
Having handed over department space for COVID-19 management , they had to evolve rapidly to cope with the ensuing professional and personal challenges .
The hospital ’ s radiological physics department , which provides medical physics services to all departments that utilize ionizing radiation , took the lead role in managing cancer patients .
As well as maintaining equipment and infrastructure , the team needed to rearrange radiation physics equipment and facilities to @ @ @ @ @ @ @ included establishing protocols for radiography and radiotherapy delivery , maintaining the quality of diagnostic and treatment systems , achieving high patient throughput in the minimum time possible and managing the workload with a reduced workforce .
Priya Saini is a medical physicist in the hospital ’ s radiological physics department .
Here is her account of maintaining a radiotherapy service in the midst of a pandemic .
During lockdown , I worked on cobalt teletherapy ( on the Bhabhatron-II system ) and brachytherapy .
My work included treatment planning , radiation safety monitoring @ @ @ @ @ @ @ routine equipment calibration and treatment plan reviews , as well as teaching and research .
In early March , at the start of the pandemic , COVID-19 isolation wards were created in one or two departments in our hospital .
As the number of patients increased , our cancer wards and other departments ’ wards were also converted into isolation wards .
Our physics and dosimetry facilities were vacated for doctors and nurses treating COVID-19 patients .
At that time , only one room was left for us to conduct our routine work @ @ @ @ @ @ @ COVID-19 pandemic , I had many difficulties in managing patients because of lack of awareness and fear of this virus .
Then I spent extra time reading the available information and followed the guidelines given by WHO , and slowly I overcame my fear .
In our department , we used to treat 100 to 120 patients each day on the Bhabhatron-II telecobalt machine .
This number quickly halved , because it became harder for patients to travel to the hospital and some had already returned to their hometowns or villages .
However @ @ @ @ @ @ @ transferred to radiation therapy , so workload in our department slowly increased .
For certain cases , including some patients with early-stage cancer , we delivered radiation therapy over a shorter period of time .
The main reason for such hypofractionated treatments was to minimize viral exposure and the risk of contaminating patients , without reducing the effectiveness of the treatments .
Our aim was to establish a better way to treat all patients who can benefit from radiotherapy ; and not to delay the start of treatment of any patient whose deferral @ @ @ @ @ @ @ .
After lockdown , as the necessity of providing regular medical services to the general public became essential , our hospital resumed normal activity by shifting the COVID-19 patients to the university hospital and radiation treatments continued normally again .
Every day , healthcare workers screened patients with thermal scanning before registering them for treatment and providing them with hand sanitizer .
To help avoid cross contamination , I made a separate box in the manual treatment planning room for each patient to store their treatment documents .
I also instructed the security @ @ @ @ @ @ @ a time into the room , with every patient advised to maintain physical distancing of one metre minimum .
Before starting treatment , every patient was verified to be COVID-19 negative .
At the brachytherapy treatment console , three people were present at the time of treatment : one technologist , one resident doctor and myself .
We maintained physical distancing from each other .
We did not allow patients or their companions to enter the treatment planning room or console and instead interacted with them while maintaining a one metre distance outside @ @ @ @ @ @ @ equipment ( PPE ) has become an emotive subject during the current COVID-19 epidemic , as an important component , though only one part , of a system to protect staff and patients from cross-infection .
During the lockdown period , however , the temperature in Jaipur reached up to 46°C .
As per guidelines at that time , we were not using centralized air conditioning , to prevent the spread of virus via air circulation .
So it was very difficult , as well as unhealthy , for us to wear PPE @ @ @ @ @ @ @ cases of intraluminal brachytherapy , there was direct interaction with patient while taking the measurements for planning .
During such instances I wore PPE kit .
After treatment completion , the PPE kits were discarded properly and I washed my hands and face with soap .
To increase awareness of COVID-19 to the patients and others , we pasted notices in the treatment planning room , the calculation room and on other rooms ’ doors , with messages in local languages : “ no entry without a mask ” , “ maintain social @ @ @ @ @ @ @ without permission ” .
We asked all ongoing patients about symptoms and other health-related issues ; if found symptomatic , patients were sent for COVID-19 tests .
My other roles included QA of the machines in the department and teaching .
We performed mechanical QA of both treatment machines weekly and performed dosimetry QA monthly .
Before starting , we would sanitize the treatment room and control console to prevent contamination and spread of the virus .
During this period , a few resident doctors in my department became COVID-19 positive .
I @ @ @ @ @ @ @ days earlier , which made me scared .
I did self-assessments for 3–4 days and also consulted with a general physician .
Following that , two technologists posted on the Bhabhatron-II machine tested positive for COVID-19 .
Following institutional protocol , they were home quarantined for 14 days .
After quarantine , they tested negative and re-joined the hospital .
As per local government instructions , undergraduate paramedical students were taught via online Zoom classes during lockdown .
There are five postgraduate students and , after lockdown , they re-joined regular classes .
@ @ @ @ @ @ @ radiotherapy technology and radiology technology , maintaining proper distance in a department seminar room .
I also instructed them regarding hospital protocols , the necessity of proper hygiene , and not to sit together without masks and maintaining social distancing .
Recently , one of the students got severe symptoms similar to COVID .
He was asked to take a COVID-19 test and not to return until he had a negative result , while the other four students were asked to self-quarantine .
After 24 hours , he tested negative and rested for @ @ @ @ @ @ @ .
The COVID-19 pandemic has affected everyone globally , and our department of radiological physics is no exception .
We are striving to keep ourselves and our near and dear safe , while continuing to provide medical physics services to all radiological facilities of our institute , without compromising international standards .

Priya Saini is a medical physicist in the radiological physics department of SMS Medical College and Hospitals in Jaipur, India. This post is part of a series on how the COVID-19 pandemic is affecting the personal and professional lives of physicists around the world. If you’d like to share your own perspective, please contact us at pwld@ioppublishing.org.
Priya Saini (right) performs quality assurance measurements on the cobalt teletherapy system at SMS Medical College and Hospitals in Jaipur. (Courtesy: Department of Radiological Physics)
India reported its first case of COVID-19 infection on 30 January 2020, and currently has the largest number of confirmed cases in Asia. The first case in the state of Rajasthan was in Jaipur, reported on 3 March. Since then, the SMS Medical College and Hospitals in Jaipur has served as the main COVID-19 treatment centre in Rajasthan. The hospital established a fully equipped outpatient department and isolation wards, as well as procuring a number of new X-ray machines and mobile X-ray units for diagnosis and treatment evaluation of COVID-19 patients.
As part of this transition, with the exception of the radiation delivery facility and a small intensive care unit for cancer patients, all other radiotherapy and radiological physics facilities were utilized for COVID-19 patient management. When lockdown was initiated end-March, there were four medical physicists in the hospital (two of whom were in vulnerable groups). Having handed over department space for COVID-19 management, they had to evolve rapidly to cope with the ensuing professional and personal challenges.
The hospital’s radiological physics department, which provides medical physics services to all departments that utilize ionizing radiation, took the lead role in managing cancer patients. As well as maintaining equipment and infrastructure, the team needed to rearrange radiation physics equipment and facilities to ensure patient services continued unhindered. Challenges included establishing protocols for radiography and radiotherapy delivery, maintaining the quality of diagnostic and treatment systems, achieving high patient throughput in the minimum time possible and managing the workload with a reduced workforce.
Priya Saini is a medical physicist in the hospital’s radiological physics department. Here is her account of maintaining a radiotherapy service in the midst of a pandemic.
Optimizing efficiency
During lockdown, I worked on cobalt teletherapy (on the Bhabhatron-II system) and brachytherapy. My work included treatment planning, radiation safety monitoring, quality assurance (QA), routine equipment calibration and treatment plan reviews, as well as teaching and research.
In early March, at the start of the pandemic, COVID-19 isolation wards were created in one or two departments in our hospital. As the number of patients increased, our cancer wards and other departments’ wards were also converted into isolation wards. Our physics and dosimetry facilities were vacated for doctors and nurses treating COVID-19 patients. At that time, only one room was left for us to conduct our routine work.
In this early phase of the COVID-19 pandemic, I had many difficulties in managing patients because of lack of awareness and fear of this virus. Then I spent extra time reading the available information and followed the guidelines given by WHO, and slowly I overcame my fear.
In our department, we used to treat 100 to 120 patients each day on the Bhabhatron-II telecobalt machine. This number quickly halved, because it became harder for patients to travel to the hospital and some had already returned to their hometowns or villages. However, some patients recommended for surgery were transferred to radiation therapy, so workload in our department slowly increased.
For certain cases, including some patients with early-stage cancer, we delivered radiation therapy over a shorter period of time. The main reason for such hypofractionated treatments was to minimize viral exposure and the risk of contaminating patients, without reducing the effectiveness of the treatments. Our aim was to establish a better way to treat all patients who can benefit from radiotherapy; and not to delay the start of treatment of any patient whose deferral may worsen the prognosis of their disease.
After lockdown, as the necessity of providing regular medical services to the general public became essential, our hospital resumed normal activity by shifting the COVID-19 patients to the university hospital and radiation treatments continued normally again. Every day, healthcare workers screened patients with thermal scanning before registering them for treatment and providing them with hand sanitizer.
To help avoid cross contamination, I made a separate box in the manual treatment planning room for each patient to store their treatment documents. I also instructed the security guard to send only one patient at a time into the room, with every patient advised to maintain physical distancing of one metre minimum. Before starting treatment, every patient was verified to be COVID-19 negative.
At the brachytherapy treatment console, three people were present at the time of treatment: one technologist, one resident doctor and myself. We maintained physical distancing from each other. We did not allow patients or their companions to enter the treatment planning room or console and instead interacted with them while maintaining a one metre distance outside the minor operating theatre.
Additional challenges
Personal protective equipment (PPE) has become an emotive subject during the current COVID-19 epidemic, as an important component, though only one part, of a system to protect staff and patients from cross-infection. During the lockdown period, however, the temperature in Jaipur reached up to 46°C. As per guidelines at that time, we were not using centralized air conditioning, to prevent the spread of virus via air circulation. So it was very difficult, as well as unhealthy, for us to wear PPE kit while treating the patients.
In cases of intraluminal brachytherapy, there was direct interaction with patient while taking the measurements for planning. During such instances I wore PPE kit. After treatment completion, the PPE kits were discarded properly and I washed my hands and face with soap.
To increase awareness of COVID-19 to the patients and others, we pasted notices in the treatment planning room, the calculation room and on other rooms’ doors, with messages in local languages: “no entry without a mask”, “maintain social distancing” and “do not enter without permission”. We asked all ongoing patients about symptoms and other health-related issues; if found symptomatic, patients were sent for COVID-19 tests.
My other roles included QA of the machines in the department and teaching. We performed mechanical QA of both treatment machines weekly and performed dosimetry QA monthly. Before starting, we would sanitize the treatment room and control console to prevent contamination and spread of the virus.
During this period, a few resident doctors in my department became COVID-19 positive. I had interacted with one of them two days earlier, which made me scared. I did self-assessments for 3–4 days and also consulted with a general physician. Following that, two technologists posted on the Bhabhatron-II machine tested positive for COVID-19. Following institutional protocol, they were home quarantined for 14 days. After quarantine, they tested negative and re-joined the hospital.
As per local government instructions, undergraduate paramedical students were taught via online Zoom classes during lockdown. There are five postgraduate students and, after lockdown, they re-joined regular classes. I conducted many classes for students of radiotherapy technology and radiology technology, maintaining proper distance in a department seminar room. I also instructed them regarding hospital protocols, the necessity of proper hygiene, and not to sit together without masks and maintaining social distancing.
Recently, one of the students got severe symptoms similar to COVID. He was asked to take a COVID-19 test and not to return until he had a negative result, while the other four students were asked to self-quarantine. After 24 hours, he tested negative and rested for a few days to recover from weakness.
The COVID-19 pandemic has affected everyone globally, and our department of radiological physics is no exception. We are striving to keep ourselves and our near and dear safe, while continuing to provide medical physics services to all radiological facilities of our institute, without compromising international standards.


physicsworld--2020-10-19--Accretion, not colliding spaghetti, flares up as star is devoured by black hole - Physics World

An extremely bright flare , originating from a star being devoured by a supermassive black hole , has been observed in a galaxy 215 million light-years away – making this the nearest tidal disruption event ( TDE ) ever seen .
The event was spotted by an international team of astronomers , headed by Matt Nicholl at the University of Birmingham .
They caught the event well before its climax using instruments at the European Southern Observatory ( ESO ) in Chile .
For the first time , the observations allowed astronomers to connect the characteristic brightening of these events @ @ @ @ @ @ @ .
If a star wanders too close to the supermassive black hole at the centre of its galaxy , it can experience tidal forces that exceed the gravitational forces holding the star together .
As a result , the star will be dramatically shredded into thin streams of debris , through the process of spaghettification .
During these TDEs , stellar remnants will flare , emitting large amounts of light .
Currently , there are two competing theories for these surges in brightness : either they occur as material accretes onto the black @ @ @ @ @ @ @ collisions between spaghettified streams .
Although astronomers are now discovering several TDEs every year , they have yet to determine which of these theories is best .
The main problem is that as the stars disintegrate , their colliding streams , combined with strong inflows and outflows of gas , make for a messy debris geometry which is incredibly difficult to disentangle .
In September 2019 the ESO ’ s Very Large Telescope and New Technology Telescope each spotted a new surge in brightness in a spiral galaxy .
Through further calculations , @ @ @ @ @ @ @ flash originated from a supermassive black hole as large as 1 million solar masses , as it devoured a star with a similar mass to the Sun .
Over six months , the instruments recorded the event across multiple regions of the electromagnetic spectrum as its brightness grew and faded .
Owing to its proximity , Nicholl and colleagues were able to identify the TDE well before its peak brightness .
This allowed them to capture the whole process unfolding , well before the geometry of the debris became too convoluted to untangle @ @ @ @ @ @ @ of key absorption lines in the stellar debris , Nicholl ’ s team showed that the origin of the TDE ’ s early optical emission was dominated by an outflow of bright material , with speeds reaching roughly 10,000 km/s .
Then , after around 30 days , the outflow underwent a sudden transition : first cooling , and then contracting .
Overall , the size and mass of the outflow remained consistent with the high ratio between optical and -ray emissions observed by the team , as well as in many TDEs @ @ @ @ @ @ @ the outflow was more likely to have been powered by black hole accretion , instead of collisions between spaghettified streams of debris .
With the upcoming launch of ESO ’ s Extremely Large Telescope , now scheduled for first light in 2025 , the team ’ s findings will provide researchers with key guidance as they uncover increasingly fainter and more rapidly evolving TDEs .
The research is described in a paper in Monthly Notices of the Royal Astronomical Society .

Flare up: artist’s impression of a star in the foreground experiencing spaghettification as is sucked in by a supermassive black hole. (Courtesy: ESO/M Kornmesser)
An extremely bright flare, originating from a star being devoured by a supermassive black hole, has been observed in a galaxy 215 million light-years away – making this the nearest tidal disruption event (TDE) ever seen. The event was spotted by an international team of astronomers, headed by Matt Nicholl at the University of Birmingham. They caught the event well before its climax using instruments at the European Southern Observatory (ESO) in Chile. For the first time, the observations allowed astronomers to connect the characteristic brightening of these events with rapid outflows of material from stars.
If a star wanders too close to the supermassive black hole at the centre of its galaxy, it can experience tidal forces that exceed the gravitational forces holding the star together. As a result, the star will be dramatically shredded into thin streams of debris, through the process of spaghettification. During these TDEs, stellar remnants will flare, emitting large amounts of light.
Colliding spaghetti
Currently, there are two competing theories for these surges in brightness: either they occur as material accretes onto the black hole; or they result from earlier collisions between spaghettified streams. Although astronomers are now discovering several TDEs every year, they have yet to determine which of these theories is best. The main problem is that as the stars disintegrate, their colliding streams, combined with strong inflows and outflows of gas, make for a messy debris geometry which is incredibly difficult to disentangle.
In September 2019 the ESO’s Very Large Telescope and New Technology Telescope each spotted a new surge in brightness in a spiral galaxy. Through further calculations, Nicholl’s team concluded that the flash originated from a supermassive black hole as large as 1 million solar masses, as it devoured a star with a similar mass to the Sun.
Over six months, the instruments recorded the event across multiple regions of the electromagnetic spectrum as its brightness grew and faded. Owing to its proximity, Nicholl and colleagues were able to identify the TDE well before its peak brightness. This allowed them to capture the whole process unfolding, well before the geometry of the debris became too convoluted to untangle.
Sudden transition
By tracking changes in the blueshift of key absorption lines in the stellar debris, Nicholl’s team showed that the origin of the TDE’s early optical emission was dominated by an outflow of bright material, with speeds reaching roughly 10,000 km/s. Then, after around 30 days, the outflow underwent a sudden transition: first cooling, and then contracting.
Overall, the size and mass of the outflow remained consistent with the high ratio between optical and -ray emissions observed by the team, as well as in many TDEs from previous studies. This suggested that the outflow was more likely to have been powered by black hole accretion, instead of collisions between spaghettified streams of debris.
With the upcoming launch of ESO’s Extremely Large Telescope, now scheduled for first light in 2025, the team’s findings will provide researchers with key guidance as they uncover increasingly fainter and more rapidly evolving TDEs.
The research is described in a paper in Monthly Notices of the Royal Astronomical Society.


physicsworld--2020-10-20--Optical receiver for space communications has ‘unprecedented’ sensitivity - Physics World

The most sensitive receiver to date for picking up optical signals in free space has been designed and demonstrated by researchers in Sweden .
Peter Andrekson and colleagues at Chalmers University of Technology say they achieved this “ unprecedented ” sensitivity of one photon per bit of information in their receiver using a novel approach to signal preparation , combined with virtually noiseless amplification at the receiver .
Their technique could have important implications for future space missions .
As space agencies seek to both expand their scope of exploration , and improve the data outputs of their satellites , @ @ @ @ @ @ @ keep up .
To enable operation at higher data rates , and transmissions across larger distances , optical signals are now increasingly being considered over radio waves , owing to their lower power losses during propagation .
All the same , losses can be substantial in the vast distances of space .
To realize higher transmission rates using as few photons as possible , receivers with the highest possible sensitivities are critical for success .
To achieve this , Andrekson ’ s team introduce a new setup in which data are first encoded @ @ @ @ @ @ @ combined with a continuous pump light wave at a different frequency .
When these waves are passed through a nonlinear optical fibre , they then generate a third “ idler ” wave .
Afterwards , all three waves are amplified to the desired output power , and launched into free space .
At the receiving end , the depleted signal is captured in an optical fibre , then amplified by a phase-sensitive optical amplifier – a device unique in adding almost no noise to signals .
Finally , the restored signal reaches a @ @ @ @ @ @ @ can be recovered .
Currently , even the most sophisticated free-space optical communications systems can only run at speeds of under 1 Gb/s , and require ultracold temperatures to operate .
In contrast , the system designed by Andrekson ’ s team achieved a receiver sensitivity of close to one photon per bit of information at room temperature , enabling a data transmission rate as high as 10.5 Gb/s .
In addition , the system relies on straightforward techniques for signal modulation , processing , and error calculation .
This means it could @ @ @ @ @ @ @ data rates .
Through further theoretical calculations of the sensitivity of their technique , Andrekson and colleagues concluded that it is the best possible approach to transmission across a broad range of data rates .
If integrated into the communications systems of real space missions in the future , their approach could hasten the transition from radio to optical signals for transmissions across large distances .
This could lead to operational improvements to future missions to distant parts of the solar system ; the transfers of data between satellites ; and the monitoring @ @ @ @ @ @ @ optical technique LIDAR .
The research is described in Light : Science & Applications .

Space communications: an illustration of the new concept for using light to communicate in space. (Courtesy: Yen Strandqvist/Chalmers University of Technology)
The most sensitive receiver to date for picking up optical signals in free space has been designed and demonstrated by researchers in Sweden. Peter Andrekson and colleagues at Chalmers University of Technology say they achieved this “unprecedented” sensitivity of one photon per bit of information in their receiver using a novel approach to signal preparation, combined with virtually noiseless amplification at the receiver. Their technique could have important implications for future space missions.
As space agencies seek to both expand their scope of exploration, and improve the data outputs of their satellites, existing radio-based communications systems are struggling to keep up. To enable operation at higher data rates, and transmissions across larger distances, optical signals are now increasingly being considered over radio waves, owing to their lower power losses during propagation. All the same, losses can be substantial in the vast distances of space. To realize higher transmission rates using as few photons as possible, receivers with the highest possible sensitivities are critical for success.
To achieve this, Andrekson’s team introduce a new setup in which data are first encoded onto a signal light wave, then combined with a continuous pump light wave at a different frequency. When these waves are passed through a nonlinear optical fibre, they then generate a third “idler” wave. Afterwards, all three waves are amplified to the desired output power, and launched into free space. At the receiving end, the depleted signal is captured in an optical fibre, then amplified by a phase-sensitive optical amplifier – a device unique in adding almost no noise to signals. Finally, the restored signal reaches a conventional receiver, where the original information can be recovered.
Room-temperature operation
Currently, even the most sophisticated free-space optical communications systems can only run at speeds of under 1 Gb/s, and require ultracold temperatures to operate. In contrast, the system designed by Andrekson’s team achieved a receiver sensitivity of close to one photon per bit of information at room temperature, enabling a data transmission rate as high as 10.5 Gb/s. In addition, the system relies on straightforward techniques for signal modulation, processing, and error calculation. This means it could easily be scaled up to accommodate higher data rates.
Through further theoretical calculations of the sensitivity of their technique, Andrekson and colleagues concluded that it is the best possible approach to transmission across a broad range of data rates. If integrated into the communications systems of real space missions in the future, their approach could hasten the transition from radio to optical signals for transmissions across large distances. This could lead to operational improvements to future missions to distant parts of the solar system; the transfers of data between satellites; and the monitoring of Earth’s surface using the optical technique LIDAR.
The research is described in Light: Science & Applications.


physicsworld--2020-10-20--Raman microscopy: when chemicals become images - Physics World

From materials to life or earth sciences , in many cases , solely obtaining the global chemical composition of a sample is not enough to characterize it completely .
Spatial distribution and morphological information are also mandatory to give a full and realistic understanding of the sample studied .
Confocal Raman microscopy is the perfect technique to provide complete and deep chemical characterization of a sample .
With our new LabRAM Soleil ultrafast imaging confocal microscope , the result of more than 50 years of HORIBA knowledge in spectroscopy , even for the most difficult sample , you can get @ @ @ @ @ @ @ .
Join this webinar , presented by Thibault Brulé , to discover how LabRAM Soleil can solve your research challenges .
Thibault Brulé is Raman application scientist at HORIBA France , working in the Demonstration Centre at the HORIBA Laboratory in Palaiseau .
He is responsible for providing Raman spectroscopy applications support to key customers from various industries , as well as contributing to HORIBA ’ s application strategies .
Prior to joining HORIBA in 2017 , he conducted research on proteins in blood characterization based on dynamic surface enhanced Raman spectroscopy .
@ @ @ @ @ @ @ monitoring .
Thibault holds a MSc from the University of Technologies of Troyes , completed his PhD at the University of Burgundy and followed on with a postdoc fellowship at the University of Montreal .

Available to watch now, Horiba Scientific explores the evidence that Raman microscopy is a key technique for chemical characterization
Want to learn more on the subject? Watch now
From materials to life or earth sciences, in many cases, solely obtaining the global chemical composition of a sample is not enough to characterize it completely. Spatial distribution and morphological information are also mandatory to give a full and realistic understanding of the sample studied.
Confocal Raman microscopy is the perfect technique to provide complete and deep chemical characterization of a sample. With our new LabRAM Soleil ultrafast imaging confocal microscope, the result of more than 50 years of HORIBA knowledge in spectroscopy, even for the most difficult sample, you can get easily and quickly a high-definition Raman image.
Join this webinar, presented by Thibault Brulé, to discover how LabRAM Soleil can solve your research challenges.
Want to learn more on the subject? Watch now
Thibault Brulé is Raman application scientist at HORIBA France, working in the Demonstration Centre at the HORIBA Laboratory in Palaiseau. He is responsible for providing Raman spectroscopy applications support to key customers from various industries, as well as contributing to HORIBA’s application strategies. Prior to joining HORIBA in 2017, he conducted research on proteins in blood characterization based on dynamic surface enhanced Raman spectroscopy. He then applied this technique to cell-secretion monitoring. Thibault holds a MSc from the University of Technologies of Troyes, completed his PhD at the University of Burgundy and followed on with a postdoc fellowship at the University of Montreal.


physicsworld--2020-10-20--Look Up examines the age of cosmic exploration - Physics World

I ’ ve always been somewhat of an amateur astronomer .
Despite having lived most of my life in big cities ( Mumbai , London and now Bristol ) with skies often obscured by light pollution or smog , I make a point of going out and looking at the night sky a couple of times a week .
Earlier this year , during the most stringent period of lockdown , I found solace in the familiarity and allure of the cosmos .
How refreshing then to read Look Up : Our Story with the Stars by journalist , TV @ @ @ @ @ @ @ Recently , I have found myself looking up at the stars more than ever , ” she writes in the introduction .
“ Doing so is a reminder that we are so tiny compared to the vastness of what is out there.
” With a background in astrophysics , Cruddas is a leading voice in the rapidly expanding commercial space sector , and is a director at Space for Humanity , a US non-profit aimed at democratizing access to space .
Her first popular-science book aimed at adults , she describes Look Up @ @ @ @ @ @ @ ” – a fairly apt description of this short , sharp and impassioned look at the history and the future of space exploration .
As Cruddas writes in the first chapter , the majority of the human race have never been to space and , for at least the next few generations , that balance is unlikely to tip .
Indeed , of the 100 billion humans who have ever existed , fewer than 600 have left the planet .
Despite this , it is fair to say that exploring the cosmos – @ @ @ @ @ @ @ the solar system to sending robots to Mars and detecting the first planets beyond our own star system – is one of humanity ’ s most significant enterprises , and one that is only just coming into its own .
The first half of Look Up actually looks back , as Cruddas swiftly and deftly takes the reader through the history of human exploration , beginning with our own planet .
While we humans may have been looking at the heavens since time immemorial , it was only in the 1500s that the @ @ @ @ @ @ @ the Earth , beginning with Vasco da Gama ’ s journey around the Cape of Good Hope to India , and Ferdinand Magellan ’ s attempt to sail from Spain to Indonesia , travelling west .
As Cruddas describes the importance and the impact of this period – the Age of Exploration , which reshaped many people ’ s ideas of the world – she does well to highlight the cost of this kind of endeavour .
She points , for example , to the Portuguese prince often called Henry the Navigator , @ @ @ @ @ @ @ This was ] at a time when lots of sailors were afraid of setting out into the Atlantic Ocean , tasking them with recording as much information as they could about the coastlines they visited , ” she writes .
“ However , Henry was also responsible for starting the Atlantic slave trade .
So when we celebrate humans ’ drive to explore , at the same time it is also important to reflect on the horrendous mistakes we made.
” Hindsight and perspective are common themes in the book , and crucial @ @ @ @ @ @ @ difficult lessons learnt in the past should not be forgotten .
From the Age of Exploration , the book jumps to the birth of aviation , including a particularly amusing tale of the first hot-air balloon flight in Paris in 1783 .
The cargo featured a sheep , a duck and a rooster , though you ’ ll have to read the book to find out why those three animals were chosen .
She then moves on to the Space Race of the Cold War era .
Cruddas spends a significant chunk of @ @ @ @ @ @ @ of the US and Soviet pioneers who first forged a path for humans in space .
What I found particularly enjoyable and useful was the commentary she provides in parallel for both the US and Russian attempts at lunar domination , including successes and failures .
While I have read many books on the topic , Cruddas ’ lucid writing and sharp narrative made for pleasant reading , even if I had heard most of the stories before .
For those who may not be interested in reading a book only detailing the @ @ @ @ @ @ @ just the summary they need , as it highlights many important figures often sidelined .
They include JoAnn Morgan ( the first woman to become an engineer at NASA ’ s Kennedy Space Centre ) , Katherine Johnson and the other African-American women who worked as “ human computers ” at NASA , as well as the wives and families of the celebrity astronauts .
The rest of the book focuses on a rich mix of topics , from the beginning of commercial space flight ideas that took off as early as the @ @ @ @ @ @ @ Age technology .
Cruddas spends a whole chapter highlighting the various benefits , skills and technologies that investment in space has given us over the years – a list of firm facts to use the next time you come across a naysayer who brings up the old argument of investing only in Earth ’ s problems .
“ While a generation was dreaming of jetpacks , they never imagined Deliveroo , ” she writes .
“ Even though we ’ ve been launching satellites since the late 1950s , no-one during the heyday @ @ @ @ @ @ @ of cyber space – the Internet that we have become so reliant on .
But the combination of the connected world we live in today and the satellites above us is what has fuelled the unexpected space age.
” Cruddas points out that today , the lines are completely blurred between what constitutes a space company and a tech company – a fascinating point that hadn ’ t occurred to me before .
The final chapters of the book highlight the current leaders in space exploration – Elon Musk ’ s SpaceX and @ @ @ @ @ @ @ sights set on Mars , near-Earth asteroids and moons beyond our own , humans will within the next few centuries most definitely become a space-faring species .
As we look forward , it ’ s important to look back too , and with Look Up , readers will get a complete ( if somewhat brief ) narrative of our attempts to unravel the cosmos .
As Cruddas puts it : “ It is only from the vantage point of space that we are truly able to understand our Earth – a perspective that @ @ @ @ @ @ @ ”

Physics World. Members of the Institute of Physics can enjoy the full issue Taken from the October 2020 issue of. Members of the Institute of Physics can enjoy the full issue via the Physics World app
Tushna Commissariat reviews Look Up: Our Story with the Stars by Sarah Cruddas, in which she traces the past, present and future of humanity’s brush with the stars
Heaven sent Space exploration has led to technological benefits here on Earth. (Courtesy: Shutterstock/Sven Hansche)
I’ve always been somewhat of an amateur astronomer. Despite having lived most of my life in big cities (Mumbai, London and now Bristol) with skies often obscured by light pollution or smog, I make a point of going out and looking at the night sky a couple of times a week. Earlier this year, during the most stringent period of lockdown, I found solace in the familiarity and allure of the cosmos.
How refreshing then to read Look Up: Our Story with the Stars by journalist, TV presenter and author Sarah Cruddas. “Recently, I have found myself looking up at the stars more than ever,” she writes in the introduction. “Doing so is a reminder that we are so tiny compared to the vastness of what is out there.” With a background in astrophysics, Cruddas is a leading voice in the rapidly expanding commercial space sector, and is a director at Space for Humanity, a US non-profit aimed at democratizing access to space. Her first popular-science book aimed at adults, she describes Look Up as “part memoir and part manifesto” – a fairly apt description of this short, sharp and impassioned look at the history and the future of space exploration.
As Cruddas writes in the first chapter, the majority of the human race have never been to space and, for at least the next few generations, that balance is unlikely to tip. Indeed, of the 100 billion humans who have ever existed, fewer than 600 have left the planet. Despite this, it is fair to say that exploring the cosmos – from landing on the Moon and imaging the solar system to sending robots to Mars and detecting the first planets beyond our own star system – is one of humanity’s most significant enterprises, and one that is only just coming into its own.
The first half of Look Up actually looks back, as Cruddas swiftly and deftly takes the reader through the history of human exploration, beginning with our own planet. While we humans may have been looking at the heavens since time immemorial, it was only in the 1500s that the first real attempts were made to circumnavigate the Earth, beginning with Vasco da Gama’s journey around the Cape of Good Hope to India, and Ferdinand Magellan’s attempt to sail from Spain to Indonesia, travelling west. As Cruddas describes the importance and the impact of this period – the Age of Exploration, which reshaped many people’s ideas of the world – she does well to highlight the cost of this kind of endeavour.
She points, for example, to the Portuguese prince often called Henry the Navigator, who commissioned many expeditions. “[This was] at a time when lots of sailors were afraid of setting out into the Atlantic Ocean, tasking them with recording as much information as they could about the coastlines they visited,” she writes. “However, Henry was also responsible for starting the Atlantic slave trade. So when we celebrate humans’ drive to explore, at the same time it is also important to reflect on the horrendous mistakes we made.” Hindsight and perspective are common themes in the book, and crucial ones too, as a reminder that difficult lessons learnt in the past should not be forgotten.
From the Age of Exploration, the book jumps to the birth of aviation, including a particularly amusing tale of the first hot-air balloon flight in Paris in 1783. The cargo featured a sheep, a duck and a rooster, though you’ll have to read the book to find out why those three animals were chosen. She then moves on to the Space Race of the Cold War era. Cruddas spends a significant chunk of the book telling the stories and histories of the US and Soviet pioneers who first forged a path for humans in space.
What I found particularly enjoyable and useful was the commentary she provides in parallel for both the US and Russian attempts at lunar domination, including successes and failures. While I have read many books on the topic, Cruddas’ lucid writing and sharp narrative made for pleasant reading, even if I had heard most of the stories before. For those who may not be interested in reading a book only detailing the Space Race, Look Up could be just the summary they need, as it highlights many important figures often sidelined. They include JoAnn Morgan (the first woman to become an engineer at NASA’s Kennedy Space Centre), Katherine Johnson and the other African-American women who worked as “human computers” at NASA, as well as the wives and families of the celebrity astronauts.
Hindsight and perspective are common themes in the book, and crucial ones too
The rest of the book focuses on a rich mix of topics, from the beginning of commercial space flight ideas that took off as early as the 1970s, to the birth of Space Age technology. Cruddas spends a whole chapter highlighting the various benefits, skills and technologies that investment in space has given us over the years – a list of firm facts to use the next time you come across a naysayer who brings up the old argument of investing only in Earth’s problems. “While a generation was dreaming of jetpacks, they never imagined Deliveroo,” she writes. “Even though we’ve been launching satellites since the late 1950s, no-one during the heyday of the space race predicted a future of cyber space – the Internet that we have become so reliant on. But the combination of the connected world we live in today and the satellites above us is what has fuelled the unexpected space age.” Cruddas points out that today, the lines are completely blurred between what constitutes a space company and a tech company – a fascinating point that hadn’t occurred to me before.
The final chapters of the book highlight the current leaders in space exploration – Elon Musk’s SpaceX and Jeff Bezos’ Blue Origin. With sights set on Mars, near-Earth asteroids and moons beyond our own, humans will within the next few centuries most definitely become a space-faring species. As we look forward, it’s important to look back too, and with Look Up, readers will get a complete (if somewhat brief) narrative of our attempts to unravel the cosmos. As Cruddas puts it: “It is only from the vantage point of space that we are truly able to understand our Earth – a perspective that has been made possible by leaving.”
2020 HQ 256pp £16.99hb


physicsworld--2020-10-20--In vivo dosimetry should play a pivotal role in radiation therapy - Physics World

Radiation therapy is a complex procedure , with a series of equipment and dosimetry checks performed before every treatment to ensure its safety and accuracy .
However , there ’ s still potential for errors to occur during the actual radiation delivery , such as changes in patient geometry , inaccuracies in beam delivery or mispositioning of brachytherapy sources .
In vivo dosimetry ( IVD ) , which measures the dose to the patient during the treatment , could detect any such errors and help ensure the accurate delivery of radiotherapy .
But its adoption in clinical practice has so @ @ @ @ @ @ @ , at the first ESTRO Physics Workshop , a task group was created to investigate this low uptake and stimulate the wider adoption of IVD .
After three years of work , the task group has now published its recommendations for the future development and clinical use of IVD in the two most common forms of radiotherapy : external-beam photon radiotherapy ( EBRT ) and high dose rate ( HDR ) or pulsed dose rate ( PDR ) brachytherapy .
“ Our task group believes there should be more and tighter checks on @ @ @ @ @ @ @ delivery to the patient , ” explain Frank Verhaegen from Maastro Clinic and Kari Tanderup from Aarhus University Hospital , who led the EBRT and brachytherapy teams , respectively .
“ IVD is one of those techniques that all clinics could have , the equipment is available , but hardly anyone does it .
We analysed the reasons for this and tried to come up with technical requirements and guidelines for equipment manufacturers and clinical users.
” The project , which integrated academics , clinicians and equipment vendors from Europe , North America @ @ @ @ @ @ @ Fonseca and Jacob Johansen ( for brachytherapy ) , and Igor Olaciregui-Ruiz ( for EBRT ) .
The first challenge was to create a formal definition for IVD .
After much debate , the group agreed that “ IVD is a radiation measurement that is acquired while the patient is being treated , containing information related to the absorbed dose in the patient ” .
As such , an IVD system must be able to detect errors arising from equipment failure , dose calculation errors , anatomical changes , and patient ( EBRT @ @ @ @ @ @ @ errors .
Writing in an editorial in phiRO , Verhaegen and Tanderup detail the key requirements identified for IVD .
In addition to acting as a safety system to catch errors that could affect the patient , an IVD method should also provide tools for treatment adaptation and record the true dose received by the patient .
Ideally , an IVD system should record signals in real time without perturbing the dose to the patient .
But with such potential to improve radiotherapy , why is IVD is so under-utilized ?
The task @ @ @ @ @ @ @ perform IVD because they consider the clinical benefit to be too low , or because workflows are too complex and resource-heavy .
Manufacturers , meanwhile , are unwilling to invest due to limited demand from clinics and a lack of regulations .
“ It ’ s a bit of a chicken-and-egg problem , ” says Verhaegen .
“ There are quite a few products that one can buy , but they all only do part of the work .
And because there is little guidance on how to use it , people just @ @ @ @ @ @ @ IVD systems available for EBRT include point detectors placed on the patient ’ s skin in the treatment field and electronic portal imaging devices ( EPIDs ) , which use the treatment beam to image the patient .
The EBRT task group focused on EPIDs , as they are ubiquitous on modern linear accelerators , easy to use , can be automated and can perform 2D or 3D dosimetric verification .
Initially employed for verification of patient set-up on the treatment couch , EPIDs have since been adapted for dosimetric measurements , including @ @ @ @ @ @ @ EBRT requires little investment in hardware , but needs a lot of software and methodology development , ” Verhaegen notes .
Within brachytherapy , the main goal of IVD is to catch large deviations from the treatment plan that could affect the clinical outcome .
Such deviations arise , for example , from source misplacement , deviations in dwell times or anatomical changes .
In particular , the use of real-time IVD could allow treatment interruption and prevent gross errors .
IVD systems should also record smaller deviations , enabling inter-fraction adaptation , @ @ @ @ @ @ @ delivered dose .
Currently , there are two IVD methods that could be used with brachytherapy .
One involves locating a radiation detector inside the applicator itself .
While this approach can identify a variety of errors , it can not detect movement of the entire applicator with respect to the patient , which would generate serious dose errors .
A second option is to put the radiation detector on , or near to , the patient ’ s skin .
This design can detect moving applicators , but the position of the @ @ @ @ @ @ @ Both of these methods currently have some uncertainties which should be reduced , ” says Tanderup .
“ Furthermore , treatment verification and error detection relies on a rather complex post-processing of the raw signals from the detectors .
As long as software for such post-processing is not commercially available , the IVD methods will not have significant clinical value.
” Several groups , including those of Verhaegen and Tanderup , are currently working to develop novel IVD systems for brachytherapy .
To fully exploit IVD and encourage its clinical introduction , the @ @ @ @ @ @ @ vendors to address .
For starters , IVD methods require high sensitivity and specificity , to accurately identify clinically relevant errors while minimizing false alarms .
The workflow should be easy to implement in the clinic , but able to trigger alerts when needed .
In addition , IVD systems should be fully integrated with treatment planning software and treatment delivery equipment .
Automation could also accelerate the uptake of IVD , which currently involves performing a large number of manual actions , particularly for brachytherapy , and generates large amounts of data @ @ @ @ @ @ @ automated systems that interpret discrepancies between planned and monitored therapy are key , ” says Verhaegen .
“ Artificial intelligence could help a lot in catching errors , and even determining their cause and suggesting corrective action .
This is a bit of sci-fi for now , but good to aim for – if we can get vendors on board.
” Tanderup and Verhaegen hope that the task group ’ s recommendations will encourage vendors to get excited by this urgent need for complex treatment verification .
“ It may be the small @ @ @ @ @ @ @ , ” Verhaegen tells Physics World .
“ Hopefully , the recommendations will also motivate clinics with current in-house-developed IVD systems to start collecting clinical data that demonstrate that IVD has clinical value , ” adds Tanderup .

A linear accelerator with the portal dosimetry panel (EPID) deployed. (Courtesy: Murillo Bellezzo, Maastro Clinic)
Radiation therapy is a complex procedure, with a series of equipment and dosimetry checks performed before every treatment to ensure its safety and accuracy. However, there’s still potential for errors to occur during the actual radiation delivery, such as changes in patient geometry, inaccuracies in beam delivery or mispositioning of brachytherapy sources.
In vivo dosimetry (IVD), which measures the dose to the patient during the treatment, could detect any such errors and help ensure the accurate delivery of radiotherapy. But its adoption in clinical practice has so far been low.
In November 2017, at the first ESTRO Physics Workshop, a task group was created to investigate this low uptake and stimulate the wider adoption of IVD. After three years of work, the task group has now published its recommendations for the future development and clinical use of IVD in the two most common forms of radiotherapy: external-beam photon radiotherapy (EBRT) and high dose rate (HDR) or pulsed dose rate (PDR) brachytherapy.
“Our task group believes there should be more and tighter checks on radiotherapy, in particular during the beam delivery to the patient,” explain Frank Verhaegen from Maastro Clinic and Kari Tanderup from Aarhus University Hospital, who led the EBRT and brachytherapy teams, respectively. “IVD is one of those techniques that all clinics could have, the equipment is available, but hardly anyone does it. We analysed the reasons for this and tried to come up with technical requirements and guidelines for equipment manufacturers and clinical users.”
Issues arising
The project, which integrated academics, clinicians and equipment vendors from Europe, North America and Australia, was coordinated by Gabriel Fonseca and Jacob Johansen (for brachytherapy), and Igor Olaciregui-Ruiz (for EBRT). The first challenge was to create a formal definition for IVD. After much debate, the group agreed that “IVD is a radiation measurement that is acquired while the patient is being treated, containing information related to the absorbed dose in the patient”. As such, an IVD system must be able to detect errors arising from equipment failure, dose calculation errors, anatomical changes, and patient (EBRT) or applicator (brachytherapy) positioning errors.
Writing in an editorial in phiRO, Verhaegen and Tanderup detail the key requirements identified for IVD. In addition to acting as a safety system to catch errors that could affect the patient, an IVD method should also provide tools for treatment adaptation and record the true dose received by the patient. Ideally, an IVD system should record signals in real time without perturbing the dose to the patient.
But with such potential to improve radiotherapy, why is IVD is so under-utilized? The task group suggests that many clinics do not perform IVD because they consider the clinical benefit to be too low, or because workflows are too complex and resource-heavy. Manufacturers, meanwhile, are unwilling to invest due to limited demand from clinics and a lack of regulations.
“It’s a bit of a chicken-and-egg problem,” says Verhaegen. “There are quite a few products that one can buy, but they all only do part of the work. And because there is little guidance on how to use it, people just don’t use it.”
Commercial IVD systems available for EBRT include point detectors placed on the patient’s skin in the treatment field and electronic portal imaging devices (EPIDs), which use the treatment beam to image the patient. The EBRT task group focused on EPIDs, as they are ubiquitous on modern linear accelerators, easy to use, can be automated and can perform 2D or 3D dosimetric verification.
Initially employed for verification of patient set-up on the treatment couch, EPIDs have since been adapted for dosimetric measurements, including IVD. “Developing IVD methods for EBRT requires little investment in hardware, but needs a lot of software and methodology development,” Verhaegen notes.
Within brachytherapy, the main goal of IVD is to catch large deviations from the treatment plan that could affect the clinical outcome. Such deviations arise, for example, from source misplacement, deviations in dwell times or anatomical changes. In particular, the use of real-time IVD could allow treatment interruption and prevent gross errors. IVD systems should also record smaller deviations, enabling inter-fraction adaptation, and provide an estimate of the actual delivered dose.
Currently, there are two IVD methods that could be used with brachytherapy. One involves locating a radiation detector inside the applicator itself. While this approach can identify a variety of errors, it cannot detect movement of the entire applicator with respect to the patient, which would generate serious dose errors. A second option is to put the radiation detector on, or near to, the patient’s skin. This design can detect moving applicators, but the position of the detector itself may be uncertain.
“Both of these methods currently have some uncertainties which should be reduced,” says Tanderup. “Furthermore, treatment verification and error detection relies on a rather complex post-processing of the raw signals from the detectors. As long as software for such post-processing is not commercially available, the IVD methods will not have significant clinical value.”
Several groups, including those of Verhaegen and Tanderup, are currently working to develop novel IVD systems for brachytherapy.
Optimizing IVD
To fully exploit IVD and encourage its clinical introduction, the task group created a wish list for vendors to address. For starters, IVD methods require high sensitivity and specificity, to accurately identify clinically relevant errors while minimizing false alarms. The workflow should be easy to implement in the clinic, but able to trigger alerts when needed. In addition, IVD systems should be fully integrated with treatment planning software and treatment delivery equipment.
Automation could also accelerate the uptake of IVD, which currently involves performing a large number of manual actions, particularly for brachytherapy, and generates large amounts of data, especially with EBRT. “Fully automated systems that interpret discrepancies between planned and monitored therapy are key,” says Verhaegen. “Artificial intelligence could help a lot in catching errors, and even determining their cause and suggesting corrective action. This is a bit of sci-fi for now, but good to aim for – if we can get vendors on board.”
Tanderup and Verhaegen hope that the task group’s recommendations will encourage vendors to get excited by this urgent need for complex treatment verification. “It may be the small start-up companies that rise to the occasion,” Verhaegen tells Physics World. “Hopefully, the recommendations will also motivate clinics with current in-house-developed IVD systems to start collecting clinical data that demonstrate that IVD has clinical value,” adds Tanderup.


physicsworld--2020-10-21--Rippling graphene harvests thermal energy - Physics World

The rippling thermal motion of a tiny piece of graphene has been harnessed by a special circuit that delivers low-voltage electrical energy .
The system was created by researchers in US and Spain , who say that if it could be duplicated enough times on a chip , it could deliver “ clean , limitless , low-voltage power for small devices ” .
Brownian motion is the random movement of a tiny particle that is buffeted by atoms or molecules in a liquid or gas – and the idea of harnessing this motion to do useful work has a long @ @ @ @ @ @ @ 1960s , the Nobel laureate Richard Feynman popularized a thought experiment known as the “ Brownian ratchet ” , which had been conceived in 1912 by the Polish physicist Marian Smoluchowski .
This involves a paddle wheel that is connected by an axle to a ratcheted gear .
Both the paddle wheel and the ratchet are immersed in fluids .
The system is imagined as being small enough so that the impact of a single molecule is sufficient to turn the paddle .
Because of the ratchet , the paddle can only turn @ @ @ @ @ @ @ that the Brownian motion of the paddle can be harnessed to do the work of turning the axle .
However , Feynman showed that if the two fluids were at the same temperature , collisions throughout the system would prevent this from happening .
The only way work could be done , argued Feynman , is if the fluids are a different temperature , making the Brownian ratchet a heat engine .
In their new study , University of Arkansas physicist Paul Thibado and colleagues replaced the paddle with a freestanding sheet of @ @ @ @ @ @ @ atoms .
In a 2014 study , the team used scanning tunnelling microscopy to discover that graphene ripples back and forth at room temperature like a wave on the surface of the ocean .
Indeed , these ripples provide the sheets with the stability they need to exist .
The team ’ s energy harvesting circuit features a graphene sheet that ripples next to an electrode .
As the sheet ripples from concave to convex – alternately getting closer to and further away from the electrode – the pair behave as a variable @ @ @ @ @ @ @ In their new circuit design , the team combined this variable capacitor with two opposing diodes wired in parallel .
This created two separate paths for the current as it flows in each direction .
In this way , one of the paths can be used to charge up a storage capacitor that can later be emptied to perform work , such as in lighting up a bulb or powering a similar component ( see video ) .
The researchers report that their dual-diode system serves to boost the power : “ We @ @ @ @ @ @ @ behaviour of the diodes actually amplifies the power delivered , rather than reducing it , as previously thought , ” explained Thibado .
“ The rate of change in resistance provided by the diodes adds an extra factor to the power.
” But how does this setup work when the Brownian ratchet fails ?
The researchers explain that success lies in how the graphene and the circuit share a “ symbiotic ” relationship .
Even though the circuit allows the thermal environment to do work on the load resistor , the circuit and @ @ @ @ @ @ @ , meaning that no heat flows between the two .
“ This means that the second law of thermodynamics is not violated , nor is there any need to argue that ‘ Maxwell ’ s Demon ’ is separating hot and cold electrons , ” Thibado explained .
He points out that the operation of the new device is not based on an old notion that a single diode could be used in such a circuit to allow high energy electrons to flow by while blocking low energy ones .
This idea was @ @ @ @ @ @ @ physicist Léon Brillouin because it would cause one side of the diode to heat up .
This would lead to particles flowing from cold to hot , violating the second law of thermodynamics .
“ People may think that current flowing in a resistor causes it to heat up , but the Brownian current does not .
In fact , if no current were flowing , the resistor would cool down , ” Thibado added .
“ What we did was reroute the current in the circuit and transform it into something useful.
@ @ @ @ @ @ @ graphene could be incorporated into a chip to provide clean , limitless , low-voltage power for small devices or sensors , ” he adds .
With their initial study complete , the researchers are now working to store enough of the DC current produced by the energy-harvesting circuit within a capacitor for later use – a goal that will require the miniaturization of the circuit and its patterning on a silicon wafer or chip .
Should it prove possible to duplicate the circuit millions of times over on a one square millimetre chip @ @ @ @ @ @ @ be a battery replacement ” .
The research is described in the journal Physical Review E .

Limitless: Paul Thibado holds prototype energy-harvesting chips. (Courtesy: Russell Cothren)
The rippling thermal motion of a tiny piece of graphene has been harnessed by a special circuit that delivers low-voltage electrical energy. The system was created by researchers in US and Spain, who say that if it could be duplicated enough times on a chip, it could deliver “clean, limitless, low-voltage power for small devices”.
Brownian motion is the random movement of a tiny particle that is buffeted by atoms or molecules in a liquid or gas – and the idea of harnessing this motion to do useful work has a long and chequered history. In the early 1960s, the Nobel laureate Richard Feynman popularized a thought experiment known as the “Brownian ratchet”, which had been conceived in 1912 by the Polish physicist Marian Smoluchowski. This involves a paddle wheel that is connected by an axle to a ratcheted gear. Both the paddle wheel and the ratchet are immersed in fluids. The system is imagined as being small enough so that the impact of a single molecule is sufficient to turn the paddle. Because of the ratchet, the paddle can only turn in one direction and therefore it appears that the Brownian motion of the paddle can be harnessed to do the work of turning the axle.
However, Feynman showed that if the two fluids were at the same temperature, collisions throughout the system would prevent this from happening. The only way work could be done, argued Feynman, is if the fluids are a different temperature, making the Brownian ratchet a heat engine.
Freestanding graphene
In their new study, University of Arkansas physicist Paul Thibado and colleagues replaced the paddle with a freestanding sheet of graphene – a single layer of carbon atoms. In a 2014 study, the team used scanning tunnelling microscopy to discover that graphene ripples back and forth at room temperature like a wave on the surface of the ocean. Indeed, these ripples provide the sheets with the stability they need to exist.
The team’s energy harvesting circuit features a graphene sheet that ripples next to an electrode. As the sheet ripples from concave to convex – alternately getting closer to and further away from the electrode – the pair behave as a variable capacitor that produces an alternating current.
In their new circuit design, the team combined this variable capacitor with two opposing diodes wired in parallel. This created two separate paths for the current as it flows in each direction. In this way, one of the paths can be used to charge up a storage capacitor that can later be emptied to perform work, such as in lighting up a bulb or powering a similar component (see video).
The researchers report that their dual-diode system serves to boost the power: “We also found that the on-off, switch-like behaviour of the diodes actually amplifies the power delivered, rather than reducing it, as previously thought,” explained Thibado. “The rate of change in resistance provided by the diodes adds an extra factor to the power.”
“Symbiotic” relationship
But how does this setup work when the Brownian ratchet fails? The researchers explain that success lies in how the graphene and the circuit share a “symbiotic” relationship. Even though the circuit allows the thermal environment to do work on the load resistor, the circuit and the graphene operate at the same temperature, meaning that no heat flows between the two.
“This means that the second law of thermodynamics is not violated, nor is there any need to argue that ‘Maxwell’s Demon’ is separating hot and cold electrons,” Thibado explained.
He points out that the operation of the new device is not based on an old notion that a single diode could be used in such a circuit to allow high energy electrons to flow by while blocking low energy ones. This idea was dismissed in the 1950s by the French physicist Léon Brillouin because it would cause one side of the diode to heat up. This would lead to particles flowing from cold to hot, violating the second law of thermodynamics.
Rerouted current
“People may think that current flowing in a resistor causes it to heat up, but the Brownian current does not. In fact, if no current were flowing, the resistor would cool down,” Thibado added. “What we did was reroute the current in the circuit and transform it into something useful.”
“An energy-harvesting circuit based on graphene could be incorporated into a chip to provide clean, limitless, low-voltage power for small devices or sensors,” he adds.
With their initial study complete, the researchers are now working to store enough of the DC current produced by the energy-harvesting circuit within a capacitor for later use – a goal that will require the miniaturization of the circuit and its patterning on a silicon wafer or chip. Should it prove possible to duplicate the circuit millions of times over on a one square millimetre chip, Thibado says, “this can be a battery replacement”.
The research is described in the journal Physical Review E.


physicsworld--2020-10-21--Flipping the switch: how a hybrid journal went open access - Physics World

Tell us about Materials Research Express ( MRX ) ?
MRX is an open-access journal that focuses on interdisciplinary and multidisciplinary research .
Published by IOP Publishing , which publishes Physics World , it is devoted to publishing new experimental and theoretical research in the properties , characterization , design and fabrication of all classes of materials including biomaterials , nanomaterials , polymers , smart materials , electronics , thin films and more .
The journal , which offers rapid peer-review , has an international editorial board that is led by the journal ’ s editor-in-chief , Meyya Meyyappan from @ @ @ @ @ @ @ the US .
What was the original publishing model for MRX and what is it now ?
MRX launched in 2013 as a hybrid open-access journal , which gave authors the choice to make their article immediately and openly accessible at the point of publication .
From 1 October 2019 , MRX changed to a fully open-access journal model , so that papers published from that date were made immediately and permanently free to access under a Creative Commons attribution licence ( CC BY ) .
Can you explain these different publishing models @ @ @ @ @ @ @ typically require the reader to pay to access some or all of the content .
In a fully open-access journal , the final published version of record of every article is made immediately and permanently free to access and released under a licence that permits free reuse , such as a CC BY licence .
This licence grants anyone – both authors of the article and other researchers – the rights to share the article or reuse parts or all of the original content from the article for any purpose , providing that @ @ @ @ @ @ @ author and their work .
To support the costs of managing peer review and publication in a fully open-access journal , we apply an article publication charge ( APC ) to published articles , but other funding mechanisms are also used to fund open-access publication models .
What were the reasons for the switch ?
IOP Publishing has long been supportive of open access .
We wanted to show that support by flipping one of our larger journals to open access .
The move also allowed us to understand the impacts on the @ @ @ @ @ @ @ articles .
And what are the benefits of doing this ?
Through the move , we have made important materials science research freely accessible .
We ’ ve seen increased average downloads per article with some being downloaded and read over 2000 times – over 900 times in the first three months of publication alone – putting them in the top 50 of most downloaded articles since 2013 .
What were some of the challenges switching MRX to an open-access model ?
MRX is a journal of reference for the materials research community @ @ @ @ @ @ @ Retaining the same author demographic after introducing an APC was probably the biggest challenge for us but to make this transition as fair and smooth as possible , we supported authors wherever possible .
We set an APC price of £1100 and for the first month after we switched , IOP Publishing covered this APC for all submitted articles .
Following that , and throughout 2020 , we have offered authors a reduced APC of £825 – a 25 % discount – and a further discount on this for authors from lower-income countries @ @ @ @ @ @ @ The move has been well received by the community .
Although we have received submissions from over 70 countries , we have , however , seen a substantial reduction in the total number of submissions .
In 2020 we will publish about 1500 articles against almost 4500 in 2019 .
There has been an especially stark reduction in submissions from authors in India , which is a useful reminder of the considerable geographical differences in the level of financial support for open-access publishing .
Has the switch impacted the peer review and publication @ @ @ @ @ @ @ all .
IOP Publishing is committed to providing authors with a high-level author service throughout the whole publication process .
This means that both authors ’ experience and journal-quality standards will not be affected by the switch to open access and that the journal will also continue to prioritise excellence and rigour in the publishing service it provides to the whole materials science community , including authors , reviewers and readers .
Is it possible that other IOP Publishing journals may follow MRX ’ s lead ?
We are always looking at new @ @ @ @ @ @ @ access to research .
We are committed to annually reviewing the opportunities to transition our hybrid open-access journals to being fully open access .
However , converting the model of a journal that serves an active , global community of researchers requires careful consideration and our priority must always be centred around the needs of those research communities .

To mark International Open Access Week, Piera Demma Cara, publisher of Materials Research Express, talks to Michael Banks about the lessons learned from switching the journal to being fully open access
Piera Demma Cara says switching Materials Research Express to being full open access has had several benefits.
Tell us about Materials Research Express (MRX)?
MRX is an open-access journal that focuses on interdisciplinary and multidisciplinary research. Published by IOP Publishing, which publishes Physics World, it is devoted to publishing new experimental and theoretical research in the properties, characterization, design and fabrication of all classes of materials including biomaterials, nanomaterials, polymers, smart materials, electronics, thin films and more. The journal, which offers rapid peer review, has an international editorial board that is led by the journal’s editor-in-chief, Meyya Meyyappan from NASA’s Ames Research Centre in the US.
What was the original publishing model for MRX and what is it now?
MRX launched in 2013 as a hybrid open-access journal, which gave authors the choice to make their article immediately and openly accessible at the point of publication. From 1 October 2019, MRX changed to a fully open-access journal model, so that papers published from that date were made immediately and permanently free to access under a Creative Commons attribution licence (CC BY).
Can you explain these different publishing models?
Hybrid open access or subscription-only journals typically require the reader to pay to access some or all of the content. In a fully open-access journal, the final published version of record of every article is made immediately and permanently free to access and released under a licence that permits free reuse, such as a CC BY licence. This licence grants anyone – both authors of the article and other researchers – the rights to share the article or reuse parts or all of the original content from the article for any purpose, providing that there is clear attribution to the original author and their work. To support the costs of managing peer review and publication in a fully open-access journal, we apply an article publication charge (APC) to published articles, but other funding mechanisms are also used to fund open-access publication models.
What were the reasons for the switch?
IOP Publishing has long been supportive of open access. We wanted to show that support by flipping one of our larger journals to open access. The move also allowed us to understand the impacts on the journal in terms of submissions and published articles.
And what are the benefits of doing this?
Through the move, we have made important materials science research freely accessible. We’ve seen increased average downloads per article with some being downloaded and read over 2000 times – over 900 times in the first three months of publication alone – putting them in the top 50 of most downloaded articles since 2013.
What were some of the challenges switching MRX to an open-access model?
MRX is a journal of reference for the materials research community and has always been widely inclusive. Retaining the same author demographic after introducing an APC was probably the biggest challenge for us but to make this transition as fair and smooth as possible, we supported authors wherever possible. We set an APC price of £1100 and for the first month after we switched, IOP Publishing covered this APC for all submitted articles. Following that, and throughout 2020, we have offered authors a reduced APC of £825 – a 25% discount – and a further discount on this for authors from lower-income countries.
Did this have an effect?
The move has been well received by the community. Although we have received submissions from over 70 countries, we have, however, seen a substantial reduction in the total number of submissions. In 2020 we will publish about 1500 articles against almost 4500 in 2019. There has been an especially stark reduction in submissions from authors in India, which is a useful reminder of the considerable geographical differences in the level of financial support for open-access publishing.
Has the switch impacted the peer review and publication process of the journal?
Not at all. IOP Publishing is committed to providing authors with a high-level author service throughout the whole publication process. This means that both authors’ experience and journal-quality standards will not be affected by the switch to open access and that the journal will also continue to prioritise excellence and rigour in the publishing service it provides to the whole materials science community, including authors, reviewers and readers.
Is it possible that other IOP Publishing journals may follow MRX’s lead?
We are always looking at new opportunities to support open-science practices and expand access to research. We are committed to annually reviewing the opportunities to transition our hybrid open-access journals to being fully open access. However, converting the model of a journal that serves an active, global community of researchers requires careful consideration and our priority must always be centred around the needs of those research communities.
International Open Access Week runs from 19 to 25 October 2020.


physicsworld--2020-10-21--Data-driven oncology: machine learning and RayIntelligence - Physics World

Fredrik Löfman , head of machine learning at RaySearch Laboratories in Stockholm , discusses machine learning and provides an introduction @ @ @ @ @ innovation , RayIntelligence , an oncology analytics system .
Fredrik Löfman is head of machine @ @ @ @ @ .
He has a MSc in engineering physics from Chalmers University of Technology , Gothenburg @ @ @ @ @ College , London , UK , and a PhD in applied mathematics from the Royal @ @ @ @ @ , Sweden .
Since 2017 , Fredrik has established a machine-learning department at RaySearch focusing @ @ @ @ @ applications to automate and support the process of improving future cancer treatments .
The department @ @ @ @ @ , research projects and product development of machine-learning applications and analytics software in oncology .

Explore the ways in which today’s world relies on AI, and ponder how this technology might shape the world of tomorrow


physicsworld--2020-10-21--Supercooled water is stable in two different forms - Physics World

Supercooled water – that is , water that remains liquid far below its normal freezing point – does not have a uniform structure , but instead takes on two distinct forms .
This discovery , which was made by researchers at Pacific Northwest National Laboratory ( PNNL ) in the US using infrared spectroscopy , provides long-sought-after experimental evidence that could help explain some of the anomalous properties of water at extremely cold temperatures .
Water is an unusual liquid , but its ubiquity means that we often forget just how unusual it is .
Unlike most other liquids , @ @ @ @ @ @ @ the ice it forms when it freezes .
It also expands rather than contracting when it cools ( a phenomenon known as negative thermal expansion ) ; becomes less viscous when compressed ; and exists in no fewer than 17 different crystalline phases .
This atypical behaviour extends to water ’ s supercooled state , which occurs naturally in high-altitude clouds in the Earth ’ s atmosphere and in space as well as under carefully-controlled laboratory conditions .
Many of the so-called “ mixture ” models that have been developed to explain the @ @ @ @ @ @ @ undergoes a phase transition at low temperatures and high pressures , transforming from a high-density liquid phase to a low-density one .
However , it is difficult to determine which of these models is correct because data on the behaviour of liquid water between 160 K and 235 K are so sparse .
In this temperature range – the “ no man ’ s land ” of water ’ s complex phase diagram – the supercooled liquid rapidly crystallizes , making measurements difficult .
According to Bruce Kay and Greg Kimmel , who @ @ @ @ @ @ @ latest study , it was previously an open question whether this rapid crystallization is just an experimental obstacle , or a fundamental problem stemming from some instability in water before it crystallizes .
By demonstrating that liquid water at extremely cold temperatures is relatively stable , and that it exists in two structural forms , the PNNL team ’ s results come down squarely in favour of the first option .
“ The findings explain a long-standing controversy over whether or not deeply supercooled water crystallizes before it can equilibrate , ” Kimmel @ @ @ @ @ @ @ no.
” In their experiments , Kay , Kimmel and their colleagues Lori Kringle and Wyatt Thornley used infrared ( IR ) spectroscopy to study the structural transformations that occur when thin films of supercooled water are heated from 70 K ( -203°C ) to 273 K ( 0°C ) at a rate of 1010 K/s , before being cooled at rates of 5 x 109 K/s .
These rates are achieved using nanosecond laser pulses and are 104 times faster than in other techniques – a key factor in their success , @ @ @ @ @ @ @ , the films spend around 3 ns near the maximum temperature before rapidly cooling to the base temperature .
By analysing how the IR spectra of water ’ s O-H bonds evolved during these cycles , the researchers found that supercooled water can condense into a high-density , liquid-like structure .
This higher-density form coexists with a low-density structure that has physical properties more in line with the typical bonding expected for water .
The proportion of the high-density phase deceases rapidly as the temperature falls from 245 K to 190 K. This @ @ @ @ @ @ @ mixture ” models for supercooled water , and Kringle , who did most of the experimental work , adds that the structural changes they observed were reversible and reproducible .
As well as furthering our understanding of supercooled water , the new finding , which is detailed in Science , might help explain how liquid water could exist on very cold planets ( such as Jupiter , Saturn , Uranus , Neptune and beyond ) , and how supercooled water vapour creates the trails seen behind comets .

Capturing reversible changes in the structure of supercooled water. Credit: Timothy Holland, PNNL
Supercooled water – that is, water that remains liquid far below its normal freezing point – does not have a uniform structure, but instead takes on two distinct forms. This discovery, which was made by researchers at Pacific Northwest National Laboratory (PNNL) in the US using infrared spectroscopy, provides long-sought-after experimental evidence that could help explain some of the anomalous properties of water at extremely cold temperatures.
Water is an unusual liquid, but its ubiquity means that we often forget just how unusual it is. Unlike most other liquids, it is denser at ambient pressure than the ice it forms when it freezes. It also expands rather than contracting when it cools (a phenomenon known as negative thermal expansion); becomes less viscous when compressed; and exists in no fewer than 17 different crystalline phases.
This atypical behaviour extends to water’s supercooled state, which occurs naturally in high-altitude clouds in the Earth’s atmosphere and in space as well as under carefully-controlled laboratory conditions. Many of the so-called “mixture” models that have been developed to explain the oddities of supercooled water predict that it undergoes a phase transition at low temperatures and high pressures, transforming from a high-density liquid phase to a low-density one. However, it is difficult to determine which of these models is correct because data on the behaviour of liquid water between 160 K and 235 K are so sparse.
Rapid crystallization
In this temperature range – the “no man’s land” of water’s complex phase diagram – the supercooled liquid rapidly crystallizes, making measurements difficult. According to Bruce Kay and Greg Kimmel, who led the PNNL team responsible for the latest study, it was previously an open question whether this rapid crystallization is just an experimental obstacle, or a fundamental problem stemming from some instability in water before it crystallizes.
By demonstrating that liquid water at extremely cold temperatures is relatively stable, and that it exists in two structural forms, the PNNL team’s results come down squarely in favour of the first option. “The findings explain a long-standing controversy over whether or not deeply supercooled water crystallizes before it can equilibrate,” Kimmel says. “The answer is: no.”
Infrared spectroscopy experiments
In their experiments, Kay, Kimmel and their colleagues Lori Kringle and Wyatt Thornley used infrared (IR) spectroscopy to study the structural transformations that occur when thin films of supercooled water are heated from 70 K (-203°C) to 273 K (0°C) at a rate of 1010 K/s, before being cooled at rates of 5 x 109 K/s. These rates are achieved using nanosecond laser pulses and are 104 times faster than in other techniques – a key factor in their success, Kimmel says. For each heat pulse, the films spend around 3 ns near the maximum temperature before rapidly cooling to the base temperature.
By analysing how the IR spectra of water’s O-H bonds evolved during these cycles, the researchers found that supercooled water can condense into a high-density, liquid-like structure. This higher-density form coexists with a low-density structure that has physical properties more in line with the typical bonding expected for water.
Backing up “mixture” models
The proportion of the high-density phase deceases rapidly as the temperature falls from 245 K to 190 K. This observation agrees with the predictions of “mixture” models for supercooled water, and Kringle, who did most of the experimental work, adds that the structural changes they observed were reversible and reproducible.
As well as furthering our understanding of supercooled water, the new finding, which is detailed in Science, might help explain how liquid water could exist on very cold planets (such as Jupiter, Saturn, Uranus, Neptune and beyond), and how supercooled water vapour creates the trails seen behind comets.