BLOGS

Topics: Microscopy, Nanotechnology, NEMS, Physics, Research

ABSTRACT

Single-molecule microscopy has become an indispensable tool for biochemical analysis. The capability of characterizing distinct properties of individual molecules without averaging has provided us with a different perspective for the existing scientific issues and phenomena. Recently, super-resolution fluorescence microscopy techniques have overcome the optical diffraction limit by the localization of molecule positions. However, the labeling process can potentially modify the intermolecular dynamics. Based on the highly sensitive nanomechanical photothermal microscopy reported previously, we propose optimizations on this label-free microscopy technique toward localization microscopy. A localization precision of 3 Å is achieved with gold nanoparticles, and the detection of polarization-dependent absorption is demonstrated, which opens the door for further improvement with polarization modulation imaging.

FIG. 2. (a) Schematic of the measurement setup. BE: beam expander. M: mirror. WP: waveplate. LP: linear polarizer. BS: beam splitter. PD: photodetector/power meter. DM: dichroic mirror. ID: iris diaphragm. CCD: charge-coupled device camera. APD: avalanche photodiode detector. (b) The transduction scheme of the trampoline resonator. (c) SEM image of the trampoline resonator.

J. Appl. Phys. 128, 134501 (2020); https://doi.org/10.1063/5.0014905

Nanoelectromechanical photothermal polarization microscopy with 3 Å localization precision, Miao-Hsuan Chien and Silvan Schmid, Journal of Applied Physics

Image Source: Coronavirus and COVID-19: What You Should Know (WebMD)

Topics: Biology, Computer Modeling, COVID-19, Research

TOKYO (Reuters) – A Japanese supercomputer showed that humidity can have a large effect on the dispersion of virus particles, pointing to heightened coronavirus contagion risks in dry, indoor conditions during the winter months.

The finding suggests that the use of humidifiers may help limit infections during times when window ventilation is not possible, according to a study released on Tuesday by research giant Riken and Kobe University.

The researchers used the Fugaku supercomputer to model the emission and flow of virus-like particles from infected people in a variety of indoor environments.

Air humidity of lower than 30% resulted in more than double the amount of aerosolized particles compared to levels of 60% or higher, the simulations showed.

The study also indicated that clear face shields are not as effective as masks in preventing the spread of aerosols. Other findings showed that diners are more at risk from people to their side compared to across the table, and the number of singers in choruses should be limited and spaced out.

Japan supercomputer shows humidity affects aerosol spread of coronavirus, Rocky Swift, Reuters Science

Gentle breeze: illustration of the B-TENG triboelectric nanogenerator, which harvests electricity that is generated by fluttering polymer strips. (Courtesy: Xin Chen/Xiaojing Mu/Ya Yang)

Topics: Applied Physics, Nanotechnology, Polymers, Research

A new low-cost nanogenerator that can efficiently harvest electrical energy from ambient wind has been created by Ya Yang at the Beijing Institute of Nanoenergy and Nanosystems of the Chinese Academy of Sciences and colleagues. The team reports that the device achieves high electrical conversion efficiencies for breezes of 4–8 m/s (14–28 km/h) and says that it could be used to generate electricity in everyday situations, where conventional wind turbines are not practical.

As the drive to develop renewable sources of energy intensifies, there is growing interest in harvesting ambient energy in everyday environments. From breezes along city streets to the airflows created as we walk, the mechanical energy contained in ambient wind is abundant. The challenge is to harvest this every in an efficient and practical way. This has proven difficult using existing technologies such as piezoelectric films, which operate at very low power outputs.

Yang’s team based their new design around two well-known phenomena in physics. The first is the Bernoulli effect, which causes the fluttering of two adjacent flags to couple. If separated by a very small gap, the flags will flutter in-phase, while at slightly larger separations, they flap out-of-phase, and symmetrically about a central plane. The second is the triboelectric effect – the familiar phenomenon behind the “static electricity” that is created when different objects are rubbed together and then separated – resulting in opposite electrical charges on the objects and a voltage between the two.

Fluttering polymer ribbons harvest electrical energy, Physics World

Topics: COVID-19, Existentialism, Research

I assure you, I have been affected by this pandemic more than most. I am in a demographic that can experience deleterious effects from this virus. I have had friends and family affected directly. I have classmates that are struggling to survive. This is no hoax: it's real.

My precautions are beyond anal.

I worked in cleanrooms in the semiconductor industry, the most stringent being Class 1. The old criteria meant 0.5 microns of particles per cubic feet of air. (The newest guidelines were adopted in 2001, metric and still pretty stringent.) Each employee passed through air showers to push off any particulates from their clothing. Smokers are encouraged not to indulge, and cologne was prohibited - smoke and scent are particles. We then put our street garb in a locker, putting on green hospital gowns and fab shoes that never left the site. Then we donned cleanroom gowns - "bunny suits" - before going into the alien, HEPA-filtered environment, protecting it from any hair, skin, sweat, or dirt we could shed that would inhibit the functionality of integrated circuits. I tried to drink as little water as possible before going on the floor. Going to the bathroom, or lunch was a pain.

I have developed a unique protocol for assaulting what used to be trivial things like getting the mail, mowing the lawn - grass grows as rains fall during pandemics - or, going to the grocers for supplies.

1. I fashioned a mask from my father's handkerchiefs and rubber bands per the CDC guidelines. (I now have a collection of 5).

2. I use cloth/rubber work gloves for mowing as the rubber is tactile enough for me to operate equipment and pay for items at the grocery store.

3. After I enter the house, I immediately put all clothing - including my gloves - in the washer. I proceed to the shower.

Source: https://physics4thecool.blogspot.com/2020/04/protocols.html

The confluence of misinformation and infectious disease isn’t unique to COVID-19. Misinformation contributed to the spread of the Ebola epidemic in West Africa, and it plagues efforts to educate the public on the importance of vaccinating against measles. But when it comes to COVID-19, the pandemic has come to be defined by a tsunami of persistent misinformation to the public on everything from the utility of masks and the efficacy of school closures, to the wisdom behind social distancing, and even the promise of untested remedies. According to a study published by the National Bureau of Economic Research, areas of the country exposed to television programming that downplayed the severity of the pandemic saw greater numbers of cases and deaths—because people didn’t follow public health precautions.

In the United States, misinformation spread by elements of the media, by public leaders, and by individuals with large social media platforms has contributed to a disproportionately large share of COVID-19 burden: we house 4 percent of the global population but account for 22 percent of global COVID-19 deaths. With winter around the corner and people spending more time indoors, it is more imperative than ever that we counter misinformation and clearly communicate risks to the public; in addition, as we await the arrival of a vaccine, it is equally important to arm the public with facts. We have work to do: a recent poll found that just half of the American public plans to get a COVID-19 vaccine.

COVID Misinformation Is Killing People - This “infodemic” has to stop

Amir Bagherpour, Ali Nouri, Scientific American

Reflective markers are attached to blue 3D-printed apparatus above and below the user’s knee as well as two metal plates on the exoskeleton leg. Researchers track and compare the movement of the markers to gain insight into how well the exoskeletons fit. In this composite photo, the bottom plate has been added after the original image was taken to show the entire configuration.
Credit: N. Hanacek/NIST

Topics: Applied Physics, NIST, Research, Robotics

A shoddily tailored suit or a shrunken T-shirt may not be the most stylish, but wearing them is unlikely to hurt more than your reputation. An ill-fitting robotic exoskeleton on the battlefield or factory floor, however, could be a much bigger problem than a fashion faux pas. 

Exoskeletons, many of which are powered by springs or motors, can cause pain or injury if their joints are not aligned with the user. To help manufacturers and consumers mitigate these risks, researchers at the National Institute of Standards and Technology (NIST) developed a new measurement method to test whether an exoskeleton and the person wearing it are moving smoothly and in harmony. 

In a new report, the researchers describe an optical tracking system (OTS) not unlike the motion capture techniques used by filmmakers to bring computer-generated characters to life. 

The OTS uses special cameras that emit light and capture what is reflected back by spherical markers arranged on objects of interest. A computer calculates the position of the labeled objects in 3D space. Here, this approach was used to track the movement of an exoskeleton and test pieces, called “artifacts,” fastened to its user.

Exoskeleton Research Marches Forward With NIST Study on Fit, NIST

The spike protein of the SARS-CoV-2 virus (gray) is shown with three small antibodies (pink) attached to its receptor binding domains. The spike attaches at the left to the viral membrane (not shown). DIAMOND LIGHT SOURCE

Topics: Chemistry, COVID-19, Physics, Research

As the world anxiously awaits development of one or more vaccines to tame the SARS-CoV-2 virus, other research continues at a feverish pace to find effective treatments for the disease it causes, COVID-19. That work, in which physicists and chemists are deeply involved, has made significant strides in the past several months and has turned up a few surprises. Researchers at the University of Alberta reported at the August virtual meeting of the American Crystallographic Association that a dipeptide-based protease inhibitor used to treat a fatal coronavirus infection in cats also blocks replication of the SARS-CoV-2 virus in samples of monkey lung tissue. Joanne Lemieux, a biochemist at the university, says the antiviral, known as GC373, works by blocking the function of the main protease (M^pro), an enzyme that cleaves the polyproteins translated from viral RNA into individual proteins once it enters human cells.

Lemieux says GC373 has been shown to have no toxic effects in cats. Anivive, a California company that develops pet medicines, has applied for US Food and Drug Administration approval to begin trials in humans. Lemieux’s group crystallized the M^pro in combination with the drug and produced three-dimensional images of how the drug binds strongly to the active pocket on the enzyme. Although GC373 should be effective in its current form, the group is planning further crystallography experiments at the Stanford Synchrotron Radiation Lightsource (SSRL) and the Canadian Light Source to see if a reformulation could optimize it for human use, she says.

Cats and llamas could offer a path to coronavirus therapies, David Kramer, Physics Today

Lasers are used to create an indestructible optical fiber out of plasma.

Credit: Intense Laser-Matter Interactions Lab, University of Maryland

Topics: Lasers, Optics, Plasma, Research, Star Trek, Star Wars

In science fiction, firing powerful lasers looks easy — the Death Star can just send destructive power hurtling through space as a tight beam. But in reality, once a powerful laser has been fired, care must be taken to ensure it doesn’t get spread too thin.

If you’ve ever pointed a flashlight at a wall, you’ve observed an example of the diffusion of light. The farther you are from the wall, the more the beam spreads, resulting in a larger and dimmer spot of light. Lasers generally expand much more slowly than the beams from flashlights, but the effect of diffusion is important when the laser travels a long way or must maintain a high intensity.

Whether your goal is to achieve galactic domination or, more realistically, to accelerate electrons to incredible speeds for physics research, you’ll want as tight and powerful a beam as possible to maximize the intensity.

In their experiments, researchers can use devices called waveguides, like the optical fibers that might be carrying the internet throughout your neighborhood, to transport lasers while keeping them contained to narrow beams.

Plasma guides maintain focus of lasers, National Science Foundation Public Affairs

Topics: COVID-19, Materials Science, Optics, Photonics, Research

From chemistry to materials science to COVID-19 research, the APS is one of the most productive X-ray light sources in the world. An upgrade will make it a global leader among the next generation of light sources, opening new frontiers in science.

In the almost 25 years since the Advanced Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science User Facility, first opened at DOE’s Argonne National Laboratory, it has played an essential role in some of the most pivotal discoveries and advancements in science.

More than 5,000 researchers from around the world conduct experiments at the APS every year, and their work has, among many other notable successes, paved the way for better renewable batteries; resulted in the development of numerous new drugs; and helped to make vehicles more efficient, infrastructure materials stronger and electronics more powerful.

Advanced Photon Source Upgrade will transform the world of scientific research, Brett Hansard, Argonne National Laboratory

Credit: N. Hanacek/NIST NIST evaluated several commercially available contactless fingerprint scanning technologies in its May 2020 report.

Topics: NIST, Optics, Research

The National Institute of Standards and Technology (NIST) has evaluated several commercially available contactless fingerprint scanning technologies, allowing users to compare their performance to conventional devices that require physical contact between a person’s fingers and the scanner.

The results of the study, published today as NIST Interagency Report (NISTIR) 8307: Interoperability Assessment 2019: Contactless-to-Contact Fingerprint Capture, show that devices requiring physical contact remain superior to contactless technology at matching scanned prints to images in a database. However, when contactless devices scan multiple fingers on a hand, it improves their performance. Contactless devices that scanned multiple fingers also seldom made “false positive” errors that incorrectly matched one person’s print with another’s record.

The publication updates NIST’s July 2018 study on contactless capture and is intended to assist organizations that use fingerprint-scanning technology.

“The report summarizes the state of the art of contactless fingerprint scanning,” said John Libert, one of the report’s authors. “It can help anyone interested in adopting contactless technology to evaluate the cost in performance they might pay by switching to contactless fingerprint capture.”

NIST Study Measures Performance Accuracy of Contactless Fingerprinting Tech

Daniel Mazzone led the project to explore the mechanism that causes samarium sulphide to expand dramatically when cooled. Credit: Brookhaven National Laboratory

Topics: Materials Science, Quantum Mechanics, Research, Thermodynamics

Most metals expand when heated and contract when cooled. A few metals, however, do the opposite, exhibiting what’s known as negative thermal expansion (NTE). A team of researchers led by Ignace Jarrige and Daniel Mazzone of Brookhaven National Laboratory in the US has now found that in one such metal, yttrium-doped samarium sulphide (SmS), NTE is linked to a quantum many-body phenomenon called the Kondo effect. The work could make it possible to develop alloys in which positive and negative expansion cancel each other out, producing a composite material with a net-zero thermal expansion – a highly desirable trait for applications in aerospace and other areas of hi-tech manufacturing.

Even within the family of NTE materials, yttrium-doped SmS is an outlier, gradually expanding by up to 3% when cooled over a few hundred degrees. To better understand the mechanisms behind this “giant” NTE behavior, Mazzone and Jarrige employed X-ray diffraction and spectroscopy to investigate the material’s electronic properties.

The researchers carried out the first experiments at the Pair Distribution Function (PDF) beamline at Brookhaven’s National Synchrotron Light Source (II) (NSLS-II). They placed their SmS sample inside a liquid-helium cooled cryostat in the beam of the synchrotron X-rays and measured how the X-rays scattered off the electron clouds around the atomic ions. By tracking how these X-rays scatter, they identified the locations of the atoms in the crystal structure and the spacings between them.

“Our results show that, as the temperature drops, the atoms of this material move farther apart, causing the entire material to expand by up to 3% in volume,” says Milinda Abeykoon, the lead scientist on the PDF beamline.

Kondo effect induces giant negative thermal expansion, Belle Dumé, Physics World

Topics: History, Politics, Research, STEM

A crowd began to form at the train station in Pocatello, Idaho, around 5:15 am on Wednesday, 10 May 1950. Some 700 bleary-eyed townspeople had come to see the president and neither the day’s cold weather nor the hour would deter them. When the train chugged into town, President Harry Truman was standing on the rear platform, ready to greet the crowd. The trip to Pocatello was part of a whistle-stop tour of the northern US that took the president to numerous small towns dotting the railway.

Although Truman spent most of his time in Idaho addressing local agricultural and economic issues, in Pocatello, he talked to the crowd about science. Earlier that morning, as his train sped along the tracks, Truman had signed the National Science Foundation Act of 1950. It created the first federal agency devoted to supporting fundamental research and education across all scientific disciplines. Standing before a group of chilly Idahoans, Truman made a case for the importance of large-scale federal support for scientific research.

The story of NSF’s creation and early years of operation serves as an important window into the growth of postwar federal science policy. Science’s role in World War II had convinced many in the government that public support was needed for scientific research. Once open, NSF became an important site where debates over science policy, federal support for civilian research facilities, and federal support for education in STEM (science, technology, engineering, and mathematics) played out in postwar America.

NSF and postwar US Science, Emily Gibson, Physics Today

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

Topics: Optics, Electrical Engineering, Nanotechnology, Research, Solar Power, Spectroscopy

Silicon-based light emitter is ‘Holy Grail’ of microelectronics, say researchers
Hamish Johnston, Physics World

Green Book Blog: The Technology Dilemma, Zoë Dowling

Topics: Biology, Chemistry, COVID-19, Nanotechnology, Physics, Research, STEM

Amid coronavirus shutdowns, some grad students feel pressure to report to their labs
Michael Price, Science Magazine, AAAS

I feel their pain.

APS Physics: March.APS/about/coronavirus/

MRS: Materials Research Society/2020-Spring Meeting

Social-media bots are growing more sophisticated. Credit: OMER MESSINGER/EPA-EFE/Shutterstock

Topics: Computer Science, Internet, Politics, Research, Sociology

Social scientists battle bots to glean insights from online chatter, Heidi Ledford, Nature

MOSAiC researchers take samples on the ice near the Polarstern. Credit: Esther Horvath Alfred-Wegener-Institut (CC-BY 4.0)

Topics: Climate Change, Existentialism, Global Warming, Research

Frozen in Dwindling Ice, a Historic Expedition Finds a “New Arctic”, Chelsea Harvey, Scientific American

An animation shows the random appearance of fast radio bursts (FRBs) across the sky. (Image: © NRAO Outreach/T. Jarrett (IPAC/Caltech); B. Saxton, NRAO/AUI/NSF)

Topics: Astronomy, Astrophysics, Radio Astronomy, Research, Space Exploration

― Lewis Carroll, Alice's Adventures in Wonderland & Through the Looking-Glass

Origin of Deep-Space Radio Flash Discovered, and It's Unlike Anything Astronomers Have Ever Seen
Adam Mann, Live Science

#P4TC links:

FRBs...December 7, 2015
Fast Radio Bursts and Missing Matter...February 25, 2016
ET, FRBs and Light Sails...March 13, 2017

Topics: 3D Printing, Applied Physics, Research, Robotics, Soft Matter Physics

3D-printed active hinges change shape in response to heat
Leah Burrows, SEAS Communications, Wyss Institute, Harvard

Sir Isaac Newton's impact on Optics. Link below.

Topics: Geometry, History, Science, Research

The Top 10 Science Experiments of All Time, Adam Hadhazy, Discover Magazine

Credit: Getty Images

Topics: Internet, Neuroscience, Research, Star Trek

Scientists Demonstrate Direct Brain-to-Brain Communication in Humans
Robert Martone, Scientific American

The new printer uses low-power continuous wave lasers to create holograms on a highly sensitive photomaterial developed by the researchers. Credit: C Yves GENTET

Topics: 3D Objects, 3D Printing, Applied Physics, Holograms, Optics, Research

New printer creates extremely realistic colorful holograms, The Optical Society, Phys.org