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Pharmaceutical residues in fresh water pose a growing environmental risk

Over the past 20 years, concentrations of pharmaceuticals have increased in freshwater sources all over the world, research by environmental experts at Radboud University has revealed.

Levels of the antibiotic ciprofloxacin have reached the point of potentially causing damaging ecological effects. The research is the first to examine the risks of two particular medicines in global freshwater sources, and is published in Environmental Research Letters. The study calls for more widespread data gathering to measure the problem around the world.

“Getting an accurate picture of the environmental risks of pharmaceuticals around the world depends on the availability of data, which is limited,” says Rik Oldenkamp, lead author of the article. “It’s true that there are models, such as the ePiE model, which can give detailed predictions of pharmaceutical concentrations in the environment, but these are often only applicable to places where we already have a lot of information, such as rivers in Europe.”

The new model developed by the researchers, which builds on an existing model with a lower resolution, makes it possible to come up with worldwide predictions for individual ecoregions.

For the two pharmaceuticals investigated in the study – carbamazepine, an anti-epileptic drug, and ciprofloxacin, an antibiotic – the environmental risks were found to be 10 to 20 times higher in 2015 than in 1995. The increased human use of ciprofloxacin was found to have a particularly high impact globally. “The concentrations of this antibiotic are damaging to bacteria in the water, and these bacteria in turn play an important role in various nutrient cycles,” says Oldenkamp. “Antibiotics can also have a negative impact on the effectiveness of bacteria colonies used in water treatment.”

Antibiotic resistance has been on the agenda of the World Health Organization (WHO) and United Nations General Assembly for a few years now. “Generally, it’s seen as a problem for the health sector, as resistant bacteria can be spread within hospitals or through livestock,” says Oldenkamp. “But there’s little awareness of the role of the environment in this problem, even though that’s of crucial importance. After all, people are exposed to bacteria through wastewater treatment, rivers and lakes.”

“Our model predicts a high environmental risk for ecoregions in densely populated and dry areas such as the Middle East, yet those are precisely the areas where there is little data on pharmaceutical use and water concentrations,” says Oldenkamp. The researchers predicted human pharmaceutical consumption in these areas using regression models based on consumption in other countries, along with socio-economic and demographic information, and linked this to information related to other factors such as water sources and the number of people with access to water treatment.

“Our model shows a particular need for new data in these types of areas,” says Oldenkamp. “The model is really a starting point for creating an insight into the environmental risks posed by pharmaceuticals all over the world.”

Improved carbon capture turns CO₂ into energy storage material

Carbon dioxide (CO₂) can be transformed back into carbon at a minimal energy cost thanks to a new catalyst reported by researchers at the University of New South Wales (UNSW) and the Royal Melbourne Institute of Technology (RMIT) in their recent Nature Communications article.

Carbon dioxide emitted by human activity is a critical factor in accelerating climate change, and must be addressed to reduce the resulting harmful impacts of rising sea levels and extreme weather. In an attempt to arrest emissions, carbon capture and storage projects have been initiated around the world that aim to trap CO₂ at power plants and store it in deep geological formations, but there are concerns about the CO₂ leaking back into the atmosphere. This new discovery by Torben Daeneke and Kourosh Kalantar-Zadeh transforms dissolved CO₂ into solid carbon, which could be stored more easily or even used as an energy storage material.

Liquid benefits

Torben-Danaeke-Dorna-Esrafilzadeh — Torben Daeneke and Dorna Esrafilzadeh. (Credit: Peter Clarke/RMIT University)

Transforming waste CO₂ into useful chemicals has long been a fixation for chemists. However, CO₂ is a very stable molecule so most successful approaches have required high temperatures or pressures, or have been resource intensive in other ways, making them commercially impractical.

Kalantar-Zadeh and Daeneke have now developed a catalyst that electrochemically converts CO₂ to solid carbon at room temperature using a technique that requires very little electrical energy. They use cerium nanoparticles in a mixture of metals called galistan, which is liquid at room temperature. The use of a liquid metal surface stops the carbon from building up and slowing the reaction, and means the carbon can be removed easily.

artist's impression of a carbon-dioxide extraction system

Panel calls for more research into carbon-capture technologies

The researchers show that the carbon generated by their process is as good as commercial carbon products for storing electricity. Although the electrocatalytic system is relatively complex and uses some costly metals it is an early demonstration of a very exciting prospect. Optimization might lead to viable carbon-negative processes that could produce useful materials and chemicals, with economically inviting resource requirements, while offering environmental benefits.

Women are better at crowdfunding science, Street View explores the LHC, preventing the weaponization of science

It is International Women’s Day and the challenges faced by women in STEM careers are being discussed in forums worldwide. Some good news is a study by Henry Sauermann, Chiara Franzoni and Kourosh Shafi, who have shown that women are much more successful than men when it comes to crowdfunding money for scientific projects. The trio looked at over 700 campaigns on experiment.com, which is the largest dedicated platform to crowdfunding scientific research.

Although the majority of campaign creators on the site are men, women had a 57% success rate for reaching their targets. Their male counterparts only succeeded 43% of the time. The trio discuss the study in “Crowdfunding scientific research: Descriptive insights and correlates of funding success”.

2019 is the 30th anniversary of the World Wide Web, which was invented at CERN. Maps and navigation applications are surely some of the most useful tools available online and now even CERN’s Large Hadron Collider can be explored via Google’s Street View. You can start your journey here.

Are you worried that your research results could be used for evil purposes? If you happen to be at Canada’s University of Waterloo on 13 April, you can attend a Safeguarding science workshop to learn how to avoid the misuse of your work. Participants will explore the risk of accidental or deliberate misuse or weaponization of human pathogens and toxins, nuclear substances, advanced research, materials, and dual-use technology. Scary stuff.

Sterile neutrinos are a no-show in MINOS+ experiment

Further doubt has been cast on a claim of experimental evidence for sterile neutrinos – hypothetical particles that could be a component of dark matter. Analysis of data from the MINOS+ experiment reveals no evidence for oscillations involving sterile neutrinos. This contradicts a study published in 2018 by physicists working on the MiniBooNE experiment, which claimed significant evidence for the particles.

The Standard Model of particle physics describes three flavours of neutrinos: electron, muon and tau. As neutrinos travel through space, they oscillate from one flavour to another – something that can be measured by placing a neutrino detector some distance from a source of neutrinos such as a particle accelerator, nuclear reactor or even the Sun.

One such experiment is MiniBooNE at Fermilab, which measures how many muon neutrinos become electron neutrinos after travelling several hundred metres. In 2018, physicists working on MiniBooNE reported detecting far more electron neutrinos than predicted by the Standard Model. A similar excess was also seen more than 20 years ago in measurements of Liquid Scintillator Neutrino Detector (LSND) at the Los Alamos National Laboratory

This excess could be related to the existence of sterile neutrinos, which are hypothetical particles predicted by some extensions of the Standard Model. Sterile neutrinos would also be involved in the neutrino-oscillation process and would therefore affect how muon neutrinos transform into electron neutrinos.

Difficult to detect

Neutrinos interact very weakly with matter and are therefore very difficult to detect. But sterile neutrinos would be even more elusive because they are expected to interact via gravity alone. This means that physicists are unlikely to detect sterile neutrinos directly but could measure their effect on neutrino oscillations. Discovering sterile neutrinos could have important implications for astrophysics and cosmology because the particles are a potential component of dark matter – a mysterious substance that appears to permeate the universe and interact only via gravity.

When the MiniBooNE physicists announced their findings last year, they combined their results with the LSND data to obtain a statistical significance of 6.1σ for the electron neutrino excess. While this is well above the 5σ that is normally considered a discovery in particle physics, some physicists were not convinced that it was evidence for sterile neutrinos.

Indeed, the conclusion seems to be at odds with several different measurements done at several other neutrino detectors worldwide – which reveal no evidence for sterile neutrinos. Furthermore, the properties of sterile neutrinos inferred from MiniBooNE are not compatible with properties of dark matter inferred from cosmological observations. As a result, there is no consensus in the particle physics community about whether evidence for sterile neutrinos has been found.

Latest twist

In this latest twist in the story, physicists searching for evidence of sterile neutrinos in data from Fermilab’s MINOS+ experiment have come up empty handed. MINOS+ ran in 2013-16 and comprised two neutrino detectors – a near detector 1 km away from a neutrino source and a far detector located in a mine 735 km from Fermilab.

They were interested in how many muon neutrinos disappeared from the beam as it travels from the source to the detectors. The idea is that if more neutrinos are missing than predicted by the Standard Model, the excess could have oscillated to sterile neutrinos.

However, no such excess has been seen and the new results are incompatible with the MiniBooNE evidence for sterile neutrinos at a statistical confidence of at least 2σ. Writing in Physical Review Letters, the MINOS+ collaboration says that it has yet to study 40% of the data gathered by the experiment and working through those data using improved analysis techniques should boost the sensitivity of their result.

As for the excess seen by MiniBooNE, an optimistic view is that it could point to physics beyond the Standard Model – a result that could be just as exciting as the discovery of sterile neutrinos. A more mundane explanation could be an inaccuracy in how the response of the detector was calculated.

Streaming current measurements help explain ion transport in ångstrom-size channels

By measuring how the electric current of an ionic fluid is generated by the flow of water through ångstrom-sized channels, researchers in France and the UK have discovered that this current is sensitive to an electric field when pressure is applied. This transistor-like electrohydrodynamic effect, as they have explained it, is very similar to that recently observed in biological ion channels, such as PIEZO, and could help advance the emerging field of “iontronics”.

“Modern-day computing relies on electrons to perform calculations, but the circuitry in living organisms is different in that it exploits the transport of ions, such as sodium, chlorine and calcium, through molecular-scale channels,” explains Lydéric Bocquet of the École Normale Supérieure in Paris, who led this research effort together with Radha Boya and Nobel laureate Andre Geim of the University of Manchester. “Achieving this – often exotic – behaviour of ion transport at the nanoscale in artificial channels remains a considerable challenge, however.”

Ångström-scale channels

The researchers obtained their result by studying ion transport though ångstrom-scale channels made from two (roughly 10-nm and 150-nm) thin crystals of graphite or boron nitride separated by bilayer graphene strips on a silicon/silicon nitride substrate. The channels are assembled atop a micron-sized slit etched in the substrate, which serves as the opening of the fluidic channel, with its exit being on the other side of the wafer. These channels were developed by Boya and Geim.

Bocquet and colleagues then connect the channels to two macroscopic reservoirs filled with solutions of potassium chloride containing chlorinated silver/silver chloride electrodes. “We measure the change in ionic current using these electrodes as it flows through the channel while applying pressure drops and an applied electric field along the channel,” says Bocquet. “This so-called patch-clamp technique is similar to that employed in physiology experiments since it can measure minute electric currents.”

Indeed, the researchers say that the set up allows them to measure the pressure-driven component of the ionic current, known as the streaming current, which is an indirect measure of how water flows when confined in extremely narrow channels.

Pressure-driven flow is a supplementary parameter

“It is not easy to explain the effect we have observed using a simple physical picture,” Bocquet tells Physics World, “but it does have similarities with how electrons flow in Shockley diodes and field-effect transistors. The difference in our system is that there is pressure-driven flow as a supplementary parameter, which does not exist in electronics. This flow is probably key to iontronics.”

The finding was made possible thanks to the “ultimately thin” channels that Boya and Geim developed because it is only at these extremely small scales, typical of biological channels, that fluid and ionic transport does not fit the classical framework of hydrodynamics, says study lead author, Timothée Mouterde. “This exotic behaviour opens up a whole new world for fluid transport.”

Such devices are ideal platforms in which to mimic the behaviour of biological channels in which ions are driven though natural nanoscale channels under osmotic pressure and bioelectric potentials, add the researchers, reporting their work in Nature. “Studying such systems could help us better understand biological ionic channels such as TRAAK, TREK and PIEZO, which were recently discovered to be sensitive to pressure,” explains Mouterde. “The effect we have discovered could be the first step to assembling more advanced functions for iontronics inspired by these natural structures.”

ECR speakers offer look at radiology present and future

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Radiology is moving toward a future in which radiologists, guided by artificial intelligence (AI), will be able to work more closely with clinicians to provide precise therapies that offer patients an improved quality of life, according to a series of speakers at the opening press conference of ECR 2019.

This new beginning has just begun in oncology imaging, according to Regina Beets-Tan of the Netherlands Cancer Institute, who detailed how imaging of oncologic biomarkers is already beginning to change the management of cancer patients. Beets-Tan gave the Wilhelm Conrad Roentgen Honorary Lecture on the topic.

Cancer experts predict that within 15 years, cancer will become a chronic disease in which nine of 10 patients will have a good quality of life, Beets-Tan noted. Many of these patients will need to have their disease managed on an ongoing basis, a role for which imaging is perfect, she said. Indeed, recent studies have indicated that a strategy of watching and waiting with imaging after patients show a complete response after chemotherapy can be as effective as resection.

Artificial intelligence will play a key role in this future, Beets-Tan said. Computers will assist radiologists and enable them to provide closer support to the clinical team. Radiologists may also need to communicate more with patients as imaging is increasingly used to track their disease.

Ultimately, Beets-Tan sees some of the greatest potential with radiopharmaceuticals that have both diagnostic and therapeutic applications — so-called “theranostic” agents. Radiology will shift from a focus on following morphological changes as a sign of pathology to detecting genetic “mistakes” that are a sign of current or future disease.

“This is not a fairy tale — this is already being done in breast cancer,” she said, citing the MammaPrint molecular test, which can identify which tumours have a low risk of being life-threatening.

The role of artificial intelligence in radiology was emphasized by Elmar Kotter of University Medical Center Freiburg. Kotter reviewed the evolution of AI and noted the large number of submissions on AI that ECR received.

AI is not necessarily a new technology, and it could be at the top of the hype curve, Kotter noted. But the technology is sure to change the role of radiologists in the future, especially once issues like the integration of AI into clinical workflow are resolved. Ethical issues are also important, and they were the subject of a white paper published earlier this month by a number of radiology societies.

“AI will be very important in radiology in the future,” Kotter concluded.

For the first time, ECR is featuring a keynote speaker from outside the world of radiology: Bernadette Abela-Ridder from the World Health Organization (WHO). A doctor of veterinary medicine, Abela-Ridder leads research into neglected zoonotic diseases at the Department of Control of Neglected Tropical Diseases at WHO.

Abela-Ridder focused on the growing health problems presented by migrating populations worldwide. While it seems like the subject has become more prominent lately, she noted that the total number of migrants worldwide is actually at about the same as it’s been for years — approximately 3%.

There are a number of other misconceptions about migration, she said. For example, while immigrants to Europe have achieved widespread publicity lately, about 85% of the world’s displaced population is outside of Europe. Also, while many suspect that immigrants from developing countries introduce exotic diseases into developed nations, the vast majority of tropical diseases seen in developed nations are actually brought back by tourists.

What does this have to do with radiology? However they get there, more exotic conditions usually seen in the tropics are showing up in places like Vienna, and radiologists are often the first healthcare professionals who encounter these diseases as they interpret imaging exams. Indeed, the decision to invite Abela-Ridder as a speaker was inspired by the recent outbreak of an exotic disease in Genoa, Italy, according to Lorenzo Derchi, president of the European Society of Radiology (ESR), who moderated the panel.

Finally, Jean-Pierre Pruvo, head of the department of neuroradiology at Lille University Hospital, spoke about the role of imaging in diagnosing and managing psychiatric illness. Mental illness is exacting a growing toll in society, and it’s estimated that one in four individuals worldwide will experience some kind of illness, he noted.

Fortunately, this is another setting where imaging can help. Imaging tools such as MRI and MR spectroscopy can show evidence of neurological changes in cases of schizophrenia years before clinical evidence is obvious, Pruvo noted. Imaging can also be used to track the effectiveness of pharmaceutical therapy for mental illness in clinical trials.

In France, there are a number of projects underway to improve the integration of imaging and psychiatric care, such as the PREDIPSY project, which will soon acquire a 7-tesla MRI scanner to study biomarkers for mental illness.

This article was originally published on AuntMinnieEurope.com ©2019 by AuntMinnieEurope.com. Any copying, republication or redistribution of AuntMinnieEurope.com content is expressly prohibited without the prior written consent of AuntMinnieEurope.com.

Food supply falls as fish flee warmer seas

Global warming has already begun to affect fishing worldwide as fish flee warmer seas, a new study says.

In the last 80 years, there has been an estimated drop of more than 4% in sustainable catches for many kinds of fish and shellfish. That is the average. In some regions – the East China Sea, for instance, and Europe’s North Sea – the estimated decline was between 15% and 35%.

In the course of the last century, global average temperatures have crept up by about 1 °C above the average for most of human history, as a reaction to the unconstrained burning of fossil fuels. If the world continues to burn ever-greater volumes of coal, oil and natural gas, it could be 3 °C warmer or more by the end of the century.

Last year was only the fourth warmest for air surface temperatures, but the warmest since records began for the world’s oceans.

US researchers report in the journal Science that they looked at the impact of ocean warming in 235 populations of 124 species of fish, crustaceans and molluscs in 38 ecological regions between the years 1930 and 2010.

They then matched the world data on fish catches with ocean temperature maps to estimate what warming has done to the sustainable catch – that is, the biggest haul fishing crews can make without reducing breeding stocks for the seasons to follow.

“We were stunned to find that fisheries around the world have already responded to global warming,” says Malin Pinsky of Rutgers University, and one of the authors. “These aren’t hypothetical changes some time in the future.”

The researchers found that some species in some climate zones actually benefited from warming, and fish with faster life cycles sometimes responded well, sometimes badly to the temperature changes. Some responded by shifting their geographical range.

More climate losers

But overall, says Christopher Free, once of Rutgers and now at the University of California, Santa Barbara, “among the populations we studied, the climate losers outweigh the climate winners.”

And his colleague Olaf Jensen, also from Rutgers, says “Fish populations can only tolerate so much warning, though. Many of the species that have benefited from warming so far are likely to start declining as temperatures continue to rise.”

Fishermen off the coasts of Labrador and Newfoundland, in the Baltic, the Indian Ocean and the northeast US shelf may have seen more productive hauls of fish. But the biggest losses were in the Sea of Japan, the North Sea, off the Iberian coast and the Celtic-Biscay shelf.

Many fish species are adapted to a precise range of temperatures: they flourish not just in specific marine ecosystems but in thermal niches as well. Once things begin to change, they swim away or perish.

Marauding invaders

Fishermen in the North Atlantic have repeatedly observed changes in the available catch, as the cod shift northand the sardines migrate from increasingly uncomfortable warm waters. Warming in Mediterranean waters creates enticing conditions for invaders from the Red Sea and further south, at huge cost to the resident species.

The lesson is that fish stocks must be carefully conserved, and ocean reserves protected. Researchers have consistently warned that global warming and climate change – especially when combined with changes in ocean water chemistry as a consequence of carbon dioxide build-up in the atmosphere – could soon start to constrain an important source of nutrition: an estimated 3.2 billion people rely on the sea for an estimated 20% of their animal protein, especially in East Asia.

“This means 15% to 35% less fish available for food and employment in a region with some of the fastest-growing human populations in the world,” says Free.

“Knowing exactly how fisheries will change under future warming is challenging, but we do know that failing to adapt to changing fisheries productivity will result in less food and fewer profits relative to today.”

This article first appeared at Climate News Network

Challenges of interdisciplinary physics and the Web at 30

In this episode of Physics World Weekly, we’re celebrating the 30th anniversary of the World Wide Web. It was 30 years ago this month that Tim Berners-Lee, then a physicist-turned-computer-scientist at CERN, published a document entitled “Information management: a proposal”. The rest is history. Physics World editor Matin Durrani previews some of the various Web-related stories in the March special issue of Physics World.

Later in the podcast, our materials science editor Anna Demming discusses the challenges and opportunities of interdisciplinary research. Demming recently attended an event run by Nature Reviews Physics called “At the interface between physics and other disciplines”. While there she got the thoughts of Vittoria Colizza, Anthony Philips and Ricardo Sapienza.

As always, our general physics editor Hamish Johnston brings you a round-up of some of the other research news highlights from the website this week. If you enjoy what you hear, you can subscribe to Physics World Weekly via the Apple podcast app or your chosen podcast host.

Photonic nanojets achieve super-resolution

Sub-wavelength imaging by a photonic nanojet — A truncated sphere of titanium dioxide (TiO2) produces a photonic nanojet (PNJ) of electromagnetic radiation (seen in the central plot) that probes two gold spheres. Image credit: Victor Pacheco-Peña.

Ways to break through the diffraction limit and into the regime of subwavelength imaging have been growing ever-more creative. One tool that has proven useful in this endeavour is the photonic nanojet (PNJ) – an extremely narrow and intense beam of radiation at the interface between a dielectric particle and its surrounding medium. Now, a pair of researchers have developed a way to simultaneously minimize the particles and enhance the PNJs, which could benefit many imaging, microscopy and sensing applications, offering a resolution five times better than that of traditional PNJ imaging systems.

Victor Pacheco-Peña from Newcastle University, UK, and Miguel Beruete from the Public University of Navarra in Spain conducted numerical simulations of titanium dioxide (TiO₂) particles surrounded by air. The material was chosen specifically for its very high refractive index (around 9.95) and low absorption when excited with 50 GHz radiation, as used in these simulations. This is the key to the success of the study – traditional PNJs are produced in particles that have a lower index (around 2) and must be around five times larger than the wavelength. Thanks to the higher index of TiO₂ the particles studied by Pacheco-Peña and Beruete are just over half a wavelength across, bringing the technology to the mesoscale.

Freeing the nanojet

The first dielectric particle tested was an infinitely long cylinder. Initial results showed that a PNJ was indeed produced when the cylinder was illuminated from one side with a plane wave. However it was trapped inside the cylinder, as opposed to resting on the surface as in lower-index particles.

In order to release the PNJ from its dielectric prison, the researchers applied the Weierstrass formula, normally used in the design of solid immersion lenses, to find the distance from the centre at which the cylinder should be truncated. Simulations show that the PNJ at the cylinder’s surface enhances the power of the backscattered signal by a factor of 2.5, with a full-width at half-maximum (FWHM) of 0.14 times the wavelength.

For the second shape, Pacheco-Peña and Beruete studied something a little easier to realise experimentally; a truncated dielectric sphere with equivalent dimensions to that of the cylinder. When illuminated by a plane wave incident on the curved side, a PNJ appears at the flat face of the truncated sphere that is even narrower (FWHM of 0.06 times the wavelength) but slightly less intense (power enhancement of 1.8) than that produced by the truncated cylinder.

Soaring past the diffraction limit

Beruete and Pacheco-Pena — The two researchers involved in this study. Photo credits: Public University of Navarra; Victor Pacheco-Pena

Next the researchers investigated the ability of the PNJs to capture an image with subwavelength resolution. In another numerical model, two small gold spheres are positioned under a truncated dielectric sphere, and the backscattered signal measured from the combined system. The gold spheres are scanned around, which produces an image similar to that from a scanning probe microscope. After testing gold spheres with various separations, the researchers found that they could clearly distinguish spheres with separations as little as 0.06 times the wavelength, a resolution 5 times better than that of traditional PNJ imaging systems.

This study shows a promising future for PNJs in subwavelength imaging and sensing systems. The researchers are currently delving more deeply into other possible geometries for high-index particles, such as cubes and ellipsoids. Perhaps they can beat their own resolution record!

Read more about this work in the article published in the Journal of Applied Physics.

‘Out-of-the-box’ thinking is better by design

Think small, win big. That’s the mindset that Harvard University’s Laboratory for Integrated Science and Engineering (LISE) has, for a decade and more, tried to encourage by providing a focal point for cross-disciplinary collaboration in nanoscale science and technology. Underpinning that collective endeavour, and housed across three basement floors of the LISE building, is a suite of ultralow-vibration (ULV) facilities for scanning probe microscopy (SPM) – the engine-room, in every sense, of research breakthroughs spanning areas as diverse as high-temperature superconductivity, topological materials and advanced heterostructures.

Joseph Gibbons, principal at Wilson HGA, a Boston-based firm of architects specializing in science and technology facilities for academic and corporate clients, has been instrumental in developing LISE’s ULV capabilities, describing each new ULV lab as “a better version of the one that went before”. Here he talks to Physics World about Wilson HGA’s role in the design and commissioning of the latest ULV facility at LISE, as well as the complexities of research spaces for the study and control of exotic materials at the nanoscale.

Why are “quiet” environments so important for SPM?

It’s primarily a matter of resolution. By minimizing noise and vibration in the laboratory, scientists are able to push their SPM tools to the resolution limit, with that steady environment also enabling long-duration measurements – sometimes as long as several weeks. Unfortunately, many SPM facilities are located on metropolitan campuses with all manner of background noise from trains, subways, buses and trucks. My role as an architect is to counter these noise sources, while taking any inherent noise from the building – for example, due to elevators and air-conditioning units – out of the equation.

How do you create those stable lab conditions over the long term?

While ULV facilities have been around for decades, there are multiple schools of thought on the optimum relationship between the SPM and the base building. For the new ULV facility at LISE, we took vibration and acoustic measurements throughout the building during the initial design phase to identify sources that were eventually making their way into the lab.

From here, we designed backwards by setting benchmarking goals for a range of parameters such as resonance frequency of the plinth (the mass-inertia block on which the microscope sits), vertical natural frequencies, acoustic mitigation through redundant enclosures, and the prevention and control of infrasound (low-frequency sound at less than 20 Hz). Crucially, we were also willing to ditch design based on precedent and subjective paradigm in favour of “out-of-the-box” thinking.

In terms of the specifics, what does that out-of-the-box thinking look like?

Our design approach is based around three main goals. First, isolate the base building from the SPM plinth. Second, isolate the base building from the acoustic enclosure (the environment surrounding the plinth). And finally, isolate the plinth from the acoustic enclosure. This is a unique approach in that we have isolated the plinth from the acoustic enclosure, and both of these are isolated separately from the building in a kind of “Russian doll” configuration.

Plinth for SPM installation — Splendid isolation: the formwork for the plinth, into which concrete is poured and set (left). When installed, the SPM mounting tripod will sit on top of the large section of the composite cylindrical plinth (right). (Credit: Wilson HGA)

What approach are you using for isolation of the various building blocks of the lab?

Following requirements-gathering discussions with the scientific team, we selected passive isolation for this project, though there is still the option for active cancellation at the SPM instrument itself. Passive isolation depends on mass and, generally, higher mass yields higher performance. Our isolation set-up is completely passive, using pneumatic air springs and natural rubber.

What does that mean for active isolation?

We figure if we can get all of the ambient noise down below 1 Hz in the horizontal and vertical directions, any active isolation at the actual SPM instrument will not need to work very hard. Such active systems require low-voltage signaling between piezoelectrics which, whenever they feel a vibration, automatically generate a vibration of equal and opposite magnitude.

Designing lab space for cutting-edge materials research is an unusual niche for an architect. What attracted you to this specialism?

My background is in the fine arts and architecture, though there are parallels between the sciences and the work we do here at Wilson HGA. In architecture, for example, there’s always a problem that we’re trying to solve, or a thesis that we’re testing, in the course of the design process. That’s the same whether we’re designing a lab or an entire campus.

The secret in every case is to understand the end-user’s requirements for what constitutes an optimum operating environment for a given piece of kit. Often the things we focus on are never thought of by the scientists – for example, how to connect a vacuum pump or electrical supply into an isolated chamber.

The quest for quiet

The latest ULV facility in Harvard’s LISE building is the result of extensive consultation between Wilson HGA and senior researchers. Key features of the project are summarized below.

Double-height below-grade facility: materials of the existing facility include a mix of cast-in-place concrete and fully grouted concrete-masonry-unit (CMU) construction. The existing facility was lined with a redundant fully grouted CMU partition to form the first acoustic barrier.

Acoustic enclosure: this comprises cast-in-place concrete and a customized aluminium structured acoustic partition system. Concrete was used to lower the centre of gravity for the entire assembly and to increase mass. The assembly is isolated from the base building by natural rubber isolation pads.

Service feeds: there are no services permanently installed within the acoustic chamber, ensuring an environment that is completely decoupled from the base-building noise. A series of vibration/acoustic-isolated service feedthrough panels were designed within the concrete section of the chamber base and the adjacent concrete partitions. Services include electricity, signal wire, compressed gas, helium recovery and high/ultrahigh vacuum. There’s also a sample-transfer hatch for the connection of a molecular-beam epitaxy (MBE) chamber with the SPM.

Cylindrical SPM plinth: the composite cylindrical plinth (a cast-in-place concrete mass-inertia block) was designed specifically for this application. The set-up comprises two cylinders: a large-diameter but short cylinder on top of a small diameter but tall cylinder (not unlike an upside-down top hat). Cylinders were chosen for their naturally high resonance frequency and unique flexural modes with respect to the face of the adjacent acoustic enclosure. The lower portion is suspended from the upper, while the entire plinth floats on a pneumatic isolation system. When installed, the SPM mounting tripod will sit on top of the large section, while a hole in the plinth enables routine maintenance.

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Pharmaceutical residues in fresh water pose a growing environmental risk