Tech

Propagate light through any kind of medium - be it free space or biological tissue - and light will scatter. Robustness to scattering is a common requirement for communications and for imaging systems. Structured light, with its use of projected patterns, is resistant to scattering, and has therefore emerged as a versatile tool. In particular, modes of structured light carrying orbital angular momentum (OAM) have attracted significant attention for applications in biomedical imaging.

OAM is an internal property of light conferring a characteristic doughnut shape to the spatial profile. The polarization profile of OAM modes of light can also be structured. Superimpose two OAM modes, and you can get a vector vortex beam (VVB) characterized by a doughnut intensity distribution in the beam cross-section, and with spatially variant polarization. VVBs are considered suitable and advantageous for quantum applications in medical technology.

An innovative cancer scanner

An international team of researchers recently published a comprehensive study of VVB transmission in scattering media. The team is collaborating under the aegis of the European Union's FET-OPEN project Cancer Scan, which proposes to develop a radically new unified technological concept of biomedical detection deploying new ideas in quantum optics and quantum mechanics. The new concept is based on unified transmission and detection of photons in a three-dimensional space of orbital angular momentum, entanglement, and hyperspectral characteristics. Theoretically, these elements can contribute to developing a scanner that can screen for cancer and detect it in a single scan of the body, without any risk of radiation.

As explained in their report, the team implemented a flexible platform to generate VVBs and Gaussian beams, and investigated their propagation through a medium that mimics the features of biological tissue. They demonstrate and analyze the degradation of both the spatial profile and polarization pattern of the different modes of light.

Ready, aim, scatter

For both Gaussian beams and VVBs, the authors remark that spatial profiles undergo an abrupt change as the concentration of the medium increases beyond 0.09%: a sudden swift decrease in contrast. The authors observe that the change is due to the presence of a uniform background caused by the scattered components of the beams.

Investigating the polarization profiles, they found that VVB behavior is quite different from that of the Gaussian beams. Gaussian beams present a uniform polarization pattern that is unaffected by the scattering process. In contrast, VVBs present a complex distribution of polarization on the transverse plane. The team observed that a portion of the VVB signal becomes completely depolarized when it passes through scattering media, but a portion of the signal preserves its structure.

These insights into how interaction with scattering media can affect the behavior of structured OAM light represent a step forward in exploring how it may interact with biological tissue. The team hopes that their comprehensive study will stimulate further investigation into the effects of light-scattering tissue-mimicking media, to advance the quest for innovative biomedical detection technology.

A customizable smart window harnesses and manipulates solar power to save energy and cut costs.

Windows play multiple crucial roles in our homes. They illuminate, insulate and ventilate our spaces while providing views of — and protection from — the outdoors. Smart windows, or windows that use solar cell technology to convert sunlight into electricity, present the additional opportunity to leverage windows as energy sources.

However, incorporating solar cells into windows while balancing the other complex, and often conflicting, roles of windows proves challenging. For example, juggling luminosity preferences and energy harvesting goals throughout changing seasons requires complex and strategic approaches to material design.

“This design framework is customizable and can be applied to virtually any building around the world.” — Junhong Chen, scientist at Argonne and professor at the University of Chicago’s Pritzker School of Molecular Engineering

Scientists from the U.S. Department of Energy’s (DOE) Argonne National Laboratory, Northwestern University, the University of Chicago and University of Wisconsin-Milwaukee recently combined solar cell technology with a novel optimization approach to develop a smart window prototype that maximizes design across a wide range of criteria.

The optimization algorithm uses comprehensive physical models and advanced computational techniques to maximize overall energy usage while balancing building temperature demands and lighting requirements across locations and throughout changing seasons.

“This design framework is customizable and can be applied to virtually any building around the world,” said Junhong Chen, a scientist at Argonne and the Crown Family Professor of Molecular Engineering at the Pritzker School of Molecular Engineering at the University of Chicago. “Whether you want to maximize the amount of sunlight in a room or minimize heating or cooling efforts, this powerful optimization algorithm produces window designs that align with user needs and preferences.”

Advanced approach to optimization

The scientists demonstrated a wholistic approach to window design to maximize the overall energy efficiency of buildings while considering lighting and temperature preferences.

“We can regulate the sunlight in a room to ensure the desired luminosity while managing the amount of energy the building uses for heating and cooling,” said Wei Chen, the Wilson-Cook Professor in Engineering Design at Northwestern Engineering whose research group led the development of the optimization approach. “Additionally, the sunlight that doesn’t pass through is captured by the solar cell in the smart window and converted into electricity.”

The approach, called multicriteria optimization, adjusts thicknesses of solar cell layers in window design to meet the needs of the user. For example, to reduce the energy required to cool a building in the summer, the optimal window design might minimize the amount and type of light passing through while maintaining the desired luminosity inside. On the other hand, when winter savings are a priority, the design might maximize the amount of sunlight that passes through, thereby reducing the energy required for heating the building.

“Rather than focusing only on the amount of electricity produced by the solar cell, we consider the entire building’s energy consumption to see how we can best use solar energy to minimize it,” said Wei Chen.

In some scenarios, for example, it might be more energy efficient to allow a greater amount of light to pass through the window, instead of being converted into electricity by the solar cell, in order to decrease the electricity required for lighting and heating the building.

To determine the optimal design, the algorithm incorporates comprehensive physics-based models of the interactions between light and the materials in the smart window, as well as how the processes affect energy conversion and light transmission. The algorithm also takes into account the varying angles at which the sun hits the window throughout the day — and year — in different geographical locations.

“The model we created allows for exploration of millions of unique designs by an algorithm that mimics biological evolution,” said Wei Chen. “On top of the physics-based models, the algorithm uses computational mechanisms that resemble reproduction and genetic mutation to determine the optimal combination of each design parameter for a certain scenario.”

Promising prototype

To demonstrate the feasibility of a smart window capable of this level of customization, the scientists produced a small prototype of the window with an area of a few square centimeters.

The prototype consists of dozens of layers of varying materials that control the amount and frequency of light passing through, as well as the amount of solar energy converted into electricity.

One group of layers, made of a type of material called a perovskite, comprises the window’s solar cell, which harvests sunlight for energy conversion. The window prototype also includes a set of layers called a nanophotonic coating, developed by associate professor of mechanical engineering Cheng Sun and his research group at Northwestern’s McCormick School of Engineering. The coating tunes the frequencies of light that can pass through the window.

Each layer is tens of microns thick — thinner than the diameter of a grain of sand. The scientists chose an aperiodic design for the layers, meaning each layer varies in thickness. As the angle of the sun’s rays against the window changes throughout the day and year, the aperiodic design enables the performance of the window to vary in accordance with the user’s preferences.

“The variation in layer thickness is optimized for a wide spectrum of change in the nature of the sunlight that reaches the window,” said Sun. “This enables us to systematically allow less infrared transmission in the summertime and more in the wintertime to save energy consumption for temperature regulation, while optimizing the visible transmission for the purpose of indoor lighting and energy harvesting.”

The scientists optimized the prototype used in this study for a 2,000 square foot, single-story home in Phoenix. Based on experimental characterization of the window prototype, the scientists calculated significant annual energy savings over leading commercially available window technologies. The calculations used the EnergyPlus building model, a software developed at the National Renewable Energy Laboratory, a DOE Office of Energy Efficiency and Renewable Energy laboratory, that estimates realistic power consumption over time.

The synthesis methods the scientists used to produce the window prototype mimic common industrial-level manufacturing processes, and the scientists believe that these existing commercial processes would allow for successful scaling of the window prototype to full-size.

Future considerations include developing the same technology in a flexible form so that the smart window materials can be retrofitted to cover preexisting windows.

A paper on the study, titled “Maximizing solar energy utilization through multicriteria pareto optimization of energy harvesting and regulating smart window”, was published July 8 in Cell Reports, Physical Science.

The work was funded in part by the National Science Foundation.

Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science.

The U.S. Department of Energy’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.

A new method developed at Cold Spring Harbor Laboratory (CSHL) uses DNA sequencing to efficiently map long-range connections between different regions of the brain. The approach dramatically reduces the cost of mapping brain-wide connections compared to traditional microscopy-based methods.

Neuroscientists need anatomical maps to understand how information flows from one region of the brain to another. "Charting the cellular connections between different parts of the brain--the connectome--can help reveal how the nervous system processes information, as well as how faulty wiring contributes to mental illness and other disorders," says Longwen Huang, a postdoctoral researcher in CSHL Professor Anthony Zador's lab. Creating these maps has been expensive and time-consuming, demanding massive efforts that are out of reach for most research teams.

Researchers usually follow neurons' paths using fluorescent labels, which can highlight how individual cells branch through a tangled neural network to find and connect with their targets. But, the palette of fluorescent labels suitable for this work is limited. Researchers can inject different colored dyes into two or three parts of the brain, then trace the connections emanating from those regions. They can repeat this process, targeting new regions, to visualize additional connections. In order to generate a brain-wide map, this must be done hundreds of times, using new research animals each time.

[Watch the mouse brain connectome: https://www.youtube.com/watch?v=m8JmyCm991g]

The method developed in the Zador lab, called brain-wide individual animal connectome sequencing (BRICseq), takes a different approach. "We no longer label brain regions and their projections using colors. We are labeling them using nucleotide sequences," Huang says. Combining the four letters of the DNA code into short "barcodes" generates a virtually infinite number of labels that can distinguish one cell from one another, he explains. After labeling, researchers use DNA sequencing to analyze tiny segments of brain tissue, interpreting each recurring barcode as a signal of a cellular connection.

"The diversity of barcodes is really high compared to the number of colors we can use in science research. So now we can really label a huge amount of neurons and brain regions per animal, which allows us to map projections from multiple brain regions using these barcodes," Huang says.

The research team, including former graduate student Justus Kebschull, who worked with Huang to develop the technique, report in the journal Cell that BRICseq accurately maps region-to-region connectivity in the brains of mice. They say the approach will be widely accessible and should be adaptable to other organisms.

Therapies for treating glioblastoma brain cancer can be delivered with greater precision and existing drugs can be used in new ways. These are the conclusions from a study from Uppsala University investigating a large number of cell samples from patients with brain tumours. The researchers have characterised how changes in glioblastoma cells influence the effect of different drugs. Their findings are published in the journal Cell Reports.

Glioblastoma is a severe form of brain cancer, with a very poor prognosis. It has become increasingly evident that glioblastoma tumours contain many genetic aberrations that vary between patients. Despite this, there is still a lack of ways to tailor the therapy to take account of these changes and patients currently receive similar treatments.

"This was the starting point for our study, in which we examined how glioblastoma cells from 100 Uppsala patients responded to different drugs. To do this we used cell cultures grown from patient samples and tested more than 1,500 drug substances to see how the cells responded," says Professor Sven Nelander of the Department of Immunology, Genetics and Pathology at Uppsala University, who has been the principal investigator of the study.

The researchers then used an algorithm to investigate which changes in the cancer cells could best predict the effect of a specific drug. By means of this characterisation, they were able to group the tumours and found two main subgroups based on drug response and mutations in certain genes.

"By characterising the cells at multiple levels, we discovered unexpected associations between important genes and pathways, and different drugs. This in turn led us to find new ways to combine different drugs to maximise the effect. Our results thus provide a good starting point for further research aiming to increase precision and adapt the therapy for different glioblastoma patients. They can also be used to discover new purposes for already existing drugs," says Nelander.

HOUSTON - (July 14, 2020) - Where things get sticky happens to be where interesting science happens in a Rice University lab working to improve battery technology.

Using techniques similar to those they employed to develop laser-induced graphene, Rice chemist James Tour and his colleagues turned adhesive tape into a silicon oxide film that replaces troublesome anodes in lithium metal batteries.

For the Advanced Materials study, the researchers used an infrared laser cutter to convert the silicone-based adhesive of commercial tape into the porous silicon oxide coating, mixed with a small amount of laser-induced graphene from the tape's polyimide backing. The protective silicon oxide layer forms directly on the current collector of the battery.

The idea of using tape came from previous attempts to produce free-standing films of laser-induced graphene, Tour said. Unlike pure polyimide films, the tape produced not only laser-induced graphene from the polyimide backing but also a translucent film where the adhesive had been. That caught the curiosity of the researchers and led to further experimentation.

The layer formed when they stuck the tape to a copper current collector and lased it multiple times to quickly raise its temperature to 2,300 Kelvin (3,680 degrees Fahrenheit). That generated a porous coating composed primarily of silicon and oxygen, combined with a small amount of carbon in the form of graphene.

In experiments, the foamy film appeared to soak up and release lithium metal without allowing the formation of dendrites -- spiky protrusions -- that can short-circuit a battery and potentially cause fires. The researchers noted lithium metal tends to degrade fast during the battery's charge and discharge cycles with the bare current collector, but no such problems were observed in anodes coated with laser-induced silicon oxide (LI-SiO).

"In traditional lithium-ion batteries, lithium ions are intercalated into a graphite structure upon charging and de-intercalate as the battery discharges," said lead author Weiyin Chen, a Rice graduate student. "Six carbon atoms are used to store one lithium atom when the full capacity of graphite is used.

"But in a lithium metal anode, no graphite is used," he said. "The lithium ions directly shuttle from the surface of the metal anode as the battery discharges. Lithium metal anodes are considered a key technology for future battery development once their safety and performance issues are solved."

Lithium metal anodes can have a capacity 10 times higher than traditional graphite-lithium ion batteries. But lithium metal batteries that are devoid of graphite usually use excess lithium metal to compensate for losses caused by oxidation of the anode surface, Tour said.

"When there is zero excess lithium metal in the anodes, they generally suffer fast degradation, producing cells with very limited cycle life," said co-author Rodrigo Salvatierra, an academic visitor in the Tour lab. "On the bright side, these 'anode-free' cells become lighter and deliver better performance, but with the cost of a short life."

The researchers noted LI-SiO tripled the battery lifetimes over other zero-excess lithium metal batteries. The LI-SiO coated batteries delivered 60 charge-discharge cycles while retaining 70% of their capacity.

Tour said that could make lithium metal batteries suitable as high-performance batteries for outdoor expeditions or high-capacity storage for short-term outages in rural areas.

Using standard industrial lasers should allow industry to scale up for large-area production. Tour said the method is fast, requires no solvents and can be done in room atmosphere and temperature. He said the technique may also produce films to support metal nanoparticles, protective coatings and filters.

Maunakea, Hawaii - Astronomers have discovered the second-most distant confirmed short gamma-ray burst (SGRB) ever studied using two Maunakea Observatories in Hawaii - W. M. Keck Observatory and the international Gemini Observatory, a Program of NSF's NOIRLab.

Observations confirm the object's distance at 10 billion light-years away, placing it squarely in the epoch of cosmic high noon when the universe was in its "teenage years" and rapidly forming stars.

The appearance of an SGRB at such an early time could alter theories about their origins, particularly the length of time it takes two neutron stars to merge and produce these powerful explosions, as well as the rate of neutron star mergers in the young universe.

"This was a very exciting object to study," said Kerry Paterson, a postdoctoral associate at Northwestern University's Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and lead author of the study. "Our research now suggests neutron star mergers could occur surprisingly quickly for some systems -- with neutron star binaries spiraling together in less than a billion years to create an SGRB."

The study has been accepted in The Astrophysical Journal Letters and is available in preprint format on arXiv.org.

SGRBs are short-lived, highly-energetic bursts of gamma-ray light. The gamma-ray light lasts for less than two seconds, while the optical light can last for a matter of hours before fading. Therefore, rapid follow-up of the optical afterglow of these intense flashes of gamma-ray radiation is critical. Within just a few hours after NASA's Neil Gehrels Swift Observatory detected the object and broadcast a worldwide alert, Paterson's team quickly pointed the Gemini North and Keck I telescopes toward the location of the SGRB.

Using the Gemini Multi-Object Spectrograph followed by Keck Observatory's Multi-Object Spectrograph for Infrared Exploration (MOSFIRE) instrument, the researchers were able to measure the very faint afterglow of the object, which is named GRB181123B because it was the second burst discovered on November 23, 2018 -- Thanksgiving night.

"It was unreal," said Wen-fai Fong, assistant professor of physics and astronomy at Northwestern University and co-author of the study. "I was in New York with my family and had finished having a big Thanksgiving dinner. Just as I had gone to sleep, the alert went off and woke me up. While somewhat of a nuisance, you literally never know when you'll land a big discovery like this! I immediately triggered the Gemini observations and notified Kerry. Thankfully, she happened to be observing at Keck that night and was able to rearrange her original observing plan and repoint the telescope towards the SGRB."

"It was such an adrenaline-rush to be at Keck when the SGRB alert went off and personally move the telescope towards the object to capture data mere hours after the burst," said Paterson.

Precisely-localized SGRBs are rare, typically only 7-8 are detected per year. To pinpoint the distance of GRB181123B, the team obtained spectra of its host galaxy through follow-up observations using Keck Observatory's DEep Imaging and Multi-Object Spectrograph (DEIMOS).

"Once we obtained the optical spectrum from DEIMOS, it was clear this event was one of the most distant SGRBs measured, which further fueled our investigation to determine its precise distance," said Paterson.

This led the team to collect additional observations with Keck Observatory, along with the Gemini South telescope in Chile and Multi-Mirror Telescope in Arizona. With a distance calculated at a cosmological redshift of 1.754, the data confirmed the object is the most distant high-confidence SGRB with an optical afterglow detection ever found.

"The identification of certain patterns in the spectrum, together with the colors of the galaxy from the three observatories, allowed us to precisely constrain the distance and solidify it as one of the most distant SGRBs to date in 16 years of Swift operations," said Paterson.

Once the team identified the host galaxy, they were able to determine key properties of the parent stellar population within the galaxy that produced the SGRB.

"Performing 'forensics' to understand the local environment of SGRBs and what their home galaxies look like can tell us a lot about the underlying physics of these systems, such as how SGRB progenitors form and how long it takes for them to merge," said Fong. "We certainly did not expect to discover an extremely distant SGRB, as they are very rare and faint, but we were pleasantly surprised! This motivates us to go after every one that we possibly can."

Electrons can interfere in the same manner as water, acoustical or light waves do. When exploited in solid-state materials, such effects promise novel functionality for electronic devices, in which elements such as interferometers, lenses or collimators could be integrated for controlling electrons at the scale of mirco- and nanometres. However, so far such effects have been demonstrated mainly in one-dimensional devices, for example in nanotubes, or under specific conditions in two-dimensional graphene devices. Writing in Physical Review X, a collaboration including the Department of Physics groups of Klaus Ensslin, Thomas Ihn and Werner Wegscheider in the Laboratory for Solid State Physics and Oded Zilberberg at the Institute of Theoretical Physics, now introduces a novel general scenario for realizing electron optics in two dimensions.

The main functional principle of optical interferometers is the interference of monochromatic waves that propagate in the same direction. In such interferometers, the interference can be observed as a periodic oscillation of the transmitted intensity on varying the wavelength of the light. However, the period of the interference pattern strongly depends on the incident angle of the light, and, as a result, the interference pattern is averaged out if light is sent through the interferometer at all possible incident angles at once. The same arguments apply to the interference of matter waves as described by quantum mechanics, and in particular to interferometers in which electrons interfere.

As part of their PhD projects, experimentalist Matija Karalic and theorist Antonio Štrkalj have investigated the phenomenon of electronic interference in a solid-state system consisting of two coupled semiconductor layers, InAs and GaSb. They discovered that the band inversion and hybridization present in this system provide a novel transport mechanism that guarantees non-vanishing interference even when all angles of incidence occur. Through a combination of transport measurements and theoretical modelling, they found that their devices operate as a Fabry-Pérot interferometer in which electrons and holes form hybrid states and interfere.

The significance of these results goes firmly beyond the specific InAs/GaSb realization explored in this work, as the reported mechanism requires solely the two ingredients of band inversion and hybridization. Therefore new paths are now open for engineering electron-optical phenomena in a broad variety of materials.

We humans may not always see eye to eye on politics, religion, sports and other matters of debate. But at least we can agree on the location and size of objects in our physical surroundings. Or can we?

Not according to new research from the University of California, Berkeley, recently published in the Proceedings of the Royal Society B: Biological Sciences journal, that shows that our ability to pinpoint the exact location and size of things varies from one person to the next, and even within our own individual field of vision.

"We assume our perception is a perfect reflection of the physical world around us, but this study shows that each of us has a unique visual fingerprint," said study lead author Zixuan Wang, a UC Berkeley doctoral student in psychology.

The discovery by Wang and fellow researchers in UC Berkeley's Whitney Laboratory for Perception and Action has ramifications for the practices of medicine, technology, driving and sports, among other fields where accurate visual localization is critical.

For example, a driver who makes even a small miscalculation about the location of a pedestrian crossing the street can cause a catastrophe. Meanwhile, in sports, an error of visual judgment can lead to controversy, if not a fiercely disputed championship loss.

Take, for example, the 2004 U.S. Open quarterfinals, in which tennis icon Serena Williams lost to Jennifer Capriati after a series of questionable line calls. An umpire incorrectly overruled a line judge who called a backhand hit by Williams as in, resulting in an apology to Williams by the U.S. Tennis Association.

"Line judges need to rule on whether the ball is outside or inside the parameters. Even an error as small as half a degree of visual angle, equal to a sub-millimeter shift on the judge's retina, may influence the result of the whole match," said Wang, a die-hard tennis fan.

Researchers sought to understand if different people see objects in their surroundings exactly the same way. For example, when glancing at a coffee cup on a table, can two people agree on its exact position and whether its handle is big enough to grip? The result of a series of experiments suggest not, though there's an upside.

"We may reach for a coffee mug thousands of times in our life, and through practice we reach our target," Wang said. "That's the behavioral aspect of how we train ourselves to coordinate how we act in relation to what we see."

In the first task to test visual localization, study participants pinpointed on a computer screen the location of a circular target. In another experiment looking at variations of acuity within each person's field of vision, participants viewed two lines set a minimal distance apart and determined whether one line was located clockwise or counterclockwise to the other line.

And in an experiment measuring perception of size, participants viewed a series of arcs of varying lengths and were asked to estimate their lengths. Surprisingly, people perceived the exact same arcs to be bigger at some locations in the visual field and smaller at other locations.

Overall, the results showed remarkable variations in visual performance among the group and even within each individual's field of vision. The data were mapped to show each study participant's unique visual fingerprint of perceptual distortion.

"Though our study might suggest that the source of our visual deficiencies can originate from our brain, further investigations are needed to uncover the neural basis," said Wang.

"What's also important," she added, "is how we adapt to them and compensate for our errors."

Virginia Tech researchers have proven that a single gene can convert female Aedes aegypti mosquitoes into fertile male mosquitoes and identified a gene needed for male mosquito flight.

Male mosquitoes do not bite and are unable to transmit pathogens to humans. Female mosquitoes, on the other hand, are able to bite.

Female Aedes aegypti mosquitoes require blood to produce eggs, making them the prime carriers of the pathogens that cause Zika and dengue fever in humans.

"The presence of a male-determining locus (M locus) establishes the male sex in Aedes aegypti and the M locus is only inherited by the male offspring, much like the human Y chromosome," said Zhijian Tu, a professor in the Department of Biochemistry in the College of Agriculture and Life Sciences.

"By inserting Nix, a previously discovered male-determining gene in the M locus of Aedes aegypti, into a chromosomal region that can be inherited by females, we showed that Nix alone was sufficient to convert females to fertile males. This may have implications for developing future mosquito control techniques."

These findings were published in the Proceedings of the National Academy of Sciences.

"We also discovered that a second gene, named myo-sex, was needed for male flight. This work sheds light into the molecular basis of the function of the M locus, which contains at least 30 genes," said Azadeh Aryan, a research scientist in Tu's lab and the first author on the paper.

Aryan and colleagues generated and characterized multiple transgenic mosquito lines that expressed an extra copy of the Nix gene under the control of its own promoter. Maria Sharakhova, an assistant professor of entomology in the College of Agriculture and Life Sciences, and Anastasia Naumencko, a former graduate research assistant, mapped the chromosomal insertion site of the extra copy of Nix.

The Virginia Tech team, in collaboration with Zach Adelman's lab in the Department of Entomology at Texas A&M University and Chunhong Mao of the Biocomplexity Institute & Initiative at the University of Virginia, found that the Nix transgene alone, even without the M locus, was sufficient to convert females into males with male-specific sexually dimorphic features and male-like gene expression.

"Nix-mediated sex conversion was found to be highly penetrant and stable over many generations in the laboratory, meaning that these characteristics will be inherited for generations to come," said Michelle Anderson, a former member of the Adelman and Tu labs and currently a senior research scientist at the Pirbright Institute in the United Kingdom.

Although the Nix gene was able to convert the females into males, the converted males could not fly as they did not inherit the myo-sex gene, which is also located in the M locus.

Knocking out myo-sex in wild-type males confirmed that the lack of myo-sex in the sex-converted males is the reason why they could not fly. Although flight is needed for mating, the sex-converted males were still able to father viable sex-converted progeny when presented with cold-anesthetized wild-type females.

"Nix has great potential for developing mosquito control strategies to reduce vector populations through female-to-male sex conversion, or to aid in the Sterile Insect Technique, which requires releasing only nonbiting males," said James Biedler, a research scientist in the Tu lab.

Genetic methods that rely on mating to control mosquitoes target only one specific species. In this case, the Tu team is targeting Aedes aegypti, a species that invaded the Americas a few hundred years ago and poses a threat to humans.

However, more research is needed before potentially useful transgenic lines can be generated for initial testing in laboratory cages. "One of the challenges is to produce transgenic lines that convert females into fertile, flying male mosquitoes by inserting both the Nix and myo-sex genes into their genome together," said Adelman.

As the Tu team looks to the near future, they wish to explore the mechanism by which the Nix gene activates the male developmental pathway. The team is also interested in learning about how it evolves within mosquito species of the same genus.

"We have found that the Nix gene is present in other Aedes mosquitoes. The question is: how did this gene and the sex-determining locus evolve in mosquitoes?" said Tu, who is also an affiliated faculty member of the Fralin Life Sciences Institute.

In addition to diving into the depths of the Nix gene in mosquitoes, researchers hope that these findings will inform future investigations into homomorphic sex chromosomes that are found in other insects, vertebrates, and plants.

CHICAGO -- A mobile platform for lung cancer screening with low-dose computed tomography (CT) can be developed with limited financial risk and take powerful screening tests directly to patients, including underserved rural areas where rates of new lung cancer cases tend to be higher, according to study published today in The Annals of Thoracic Surgery.

"This study shows that if you bring it, they will come," said Rob Headrick, MD, MBA, from CHI Memorial Chest and Lung Cancer Center in Chattanooga, Tennessee. "People across the country have not been traveling to medical centers to get scans that they don't know they need. Every 3 minutes, someone in the US dies of lung cancer. We believed that if we took the technology to the people, especially those most at risk, it would be an important educational experience and lives would be saved."

Dr. Headrick and colleagues assembled a team with the ambitious task of designing and building a unique lung screening program that included a built-from-scratch bus featuring independent power, climate control, patient comfort, a portable CT scanner, and drivability. The project became known as "Breathe Easy" because it embodied the goal of reassuring many lung cancer patients through education, caring attention, hope, and pictures of their chests, helping them to "breathe easier," explained Dr. Headrick.

The bus began operations in early 2018. Researchers examined data from the 10 months that the bus was available that year. During that time, the Breathe Easy bus traveled to 104 sites and screened 548 patients. For these patients, the mean age was 62 years old with a mean smoking pack years of 41. Significant pulmonary findings were seen in 51 patients (9%). Five lung cancers were identified; four of them (80%) were early stage. In addition, non-pulmonary results also were found in 152 (28%) of the individuals screened, with the most common being moderate to severe coronary artery disease in 101 (66%) patients.

"The mobile program brings the imaging center to the patient. This can be at a place of employment, a church, or a restaurant parking lot," said Dr. Headrick. "It also makes the process quick, simple, and safe. There is no waiting room filled with people nor is a lot of time required. Screening exams have to be made simple or people will not get them done."

The Breathe Easy program currently serves all counties in east Tennessee and north Georgia within 90 miles or so from CHI Memorial--the home base of the bus. Patients are on the bus for approximately 10 to 15 minutes, depending on whether they are preregistered or a walkup. Insurance payments are collected when appropriate, though screenings are free for those who do not have insurance or can't afford the $150 price. No one is turned away for financial reasons; patients only need to meet certain National Comprehensive Cancer Network guidelines to be screened, according to Dr. Headrick.

"Lung cancer doesn't have a preference. Insured and employed as well as uninsured and unemployed individuals were screened. The goal was to increase the number of patients getting screened within our reach," he said.

The cross-trained team included a driver, a CT technician, a program director, nurse practitioner, and a physician. The front of the bus was where the CT scanner was located; whereas the back of the bus was set up for registration and shared decision-making--designed to take the patient out of the screening environment and keep them comfortable. If a physician was on the bus, he/she reviewed the films directly with the patients; otherwise, images were sent wirelessly for immediate, same-day radiologic interpretation. Smoking cessation options also were provided, when appropriate.

The biggest operational challenge identified by the researchers was the service radius. They found that the farther the bus traveled from its home base, the more difficult it was to provide follow-up assistance to patients, especially those with significant findings. Initially, the service area of the Breathe Easy bus was a 2-hour drive from CHI Memorial. However, the team shortened the distance to 1.5 hours, making it easier to manage patients and ensure successful screening events.

"The screening coordinator reached out to church groups, businesses, and other service organizations within communities to set up screening opportunities," said Dr. Headrick. "We targeted businesses and health events where the likely age would be 50 years and older. Education and communication before the events were critical. And, the more times the bus returned to the same site, the more successful the event became."

The Breathe Easy bus has now been in operation for more than 2 years, averaging approximately 100 screenings per month, with a goal of 200.In March 2020, the COVID crisis began to impact lung cancer care, causing many primary care practices and hospital-based lung screening programs to close. The Breathe Easy bus, however, continued to perform lung screenings in rural Tennessee and added diagnostic scans for patients in the CHI Memorial nodule surveillance program.

"Many patients were afraid to come to the hospital, but were very willing to go to the bus. It was viewed as a safer environment to get scans," said Dr. Headrick. "We only had one patient on the bus at a time while the spouse or next patient waited in their cars. We eliminated the waiting room, cleaned between scans, wore masks, and traveled to the patient. All of this prevented our lung screening program and nodule clinic from shutting down."

Built from Scratch

A complete original, the Breathe Easy bus took approximately 8 months to build. With engineers from medical technology and motorhome companies, along with a radiologist, pulmonologist, CT technician, and Dr. Headrick, the design team worked through various weight, balance, and practical challenges. One major consideration was the fact that CT scanning technology had not been tested on an independently powered, climate-controlled bus platform, especially one that traveled across hundreds of miles and parked on uneven surfaces.

The final cost of the prototype--covered by donated materials and funds from the CHI Memorial Foundation and local nonprofit foundations--was $650,000. A commercially reproducible vehicle is estimated to cost $850,000.

A financial analysis of the project found that the breakeven number of scans for year 1 was 428 scans. The Breathe Easy busy exceeded that by 120 scans (28%), despite only scanning patients during 10 months in 2018.

The Next Phase of the Journey

With lessons learned from the prototype vehicle, a new bus currently is under construction. This bus will include a more advanced CT scanner and coronary calcium scoring capabilities. Unlike the prototype that has a shared entrance and exit, the replacement will have a separate entry and exit way, as well as an improved interior to maximize space and throughput.

The new Breathe Easy bus is expected to be ready in late fall 2020.

"This bus has provided us with the opportunity to help advance lung cancer screening," said Dr. Headrick. "It's only through conversations and efforts such as the Breathe Easy program that we are going to erase the stigma surrounding lung cancer and change the survival rates."

Climate breakdown caused by the emissions of carbon dioxide (CO2) into the atmosphere is a major existential problem faced by humanity right now. The most acceptable solution would be complete termination of the use of fossil fuels or at least fast reduction of their use by all countries, in line with the Paris agreement. This will ensure the planetary warming is limited by 2 C. The emissions reductions, however, are slow and most of the countries are unlikely to reach the goals of reduction.

Technological solutions for the massive CO2 emissions prevention are therefore critically needed. Some technologies for CO2 capture, for instance, sorption by liquid amine chemicals are already mature to be applied on a scale, however they are costly and come with a burden of toxic chemicals disposal once they lost their CO2 binding property. Alternative technologies are therefore of a great importance.

Separation of gases with the help of membranes is emerging as a key technology for the establishment of a sustainable energy society. Wide deployment of membranes can help to capture huge amounts carbon dioxide emitted in the variety of industrial processes. In contrast to conventional CO2 capture, gas separation with membranes provides a promise for cost-efficient solution. However, to achieve economical CO2 capture at mass scale the membranes need several critical features: fast CO2 transport through their structure; high CO2 selectivity (i.e. to be a less permeable barrier for other gases); mechanical strength and chemical resistance. Additionally, membranes should be composed of materials that are inexpensive at mass production, and this is the reason why organic polymers, (conventional plastics and rubbers) are most attractive for industrial applications.

Thin-film composite is a specific architecture of the membranes to provide the robust structure for industrial applications. These membranes, that contain multiple functional layers (made of organic polymers) in its structure, offer a good solution for large-scale CO2 capture. However, even benchmark organic polymers with best separation performance (high CO2 permeability and high CO2/N2 selectivity) are struggling to deliver satisfactory separation performance, because of inability to form sufficiently thin, defect free and mechanically stable membranes.

In this work we report for the first time how ultimately thin selective layers (thickness of several nanometers) can be used to achieve desired separation properties. We have used well-known polymers for this study: polyether block amide (Pebax-1657) as selective layer and polydimethylsiloxane (PDMS) as gutter layer and examined what happens with the gas separation property when thickness of the selective layer pushed to the extreme of several nanometers. We have discovered that when selective layer of separation membranes becomes very thin it can form specific interface with gutter layer in composite structure. This nanoscale interface delivered unexpectedly high selectivity towards CO2. Gentle and ultra-short plasma treatment of the hydrophobic PDMS layer that is needed to promote adhesion with hydrophilic selective layer revealed itself as a tool to control and tune the "activity" of the molecular interface between two polymers.

We found that this interface made a determining impact on the membranes CO2 selectivity. Together with high permeation rates enabled by low thickness, developed membranes fit nicely into the area of the separation properties needed for industrial CO2 capture (e.g. post-combustion capture at fossil fueled power plants). These results open a new unexplored area of the interface-governed gas separation that can be used by engineers to design more efficient membranes for variety of useful applications.

PITTSBURGH--Kitchen robots are a popular vision of the future, but if a robot of today tries to grasp a kitchen staple such as a clear measuring cup or a shiny knife, it likely won't be able to. Transparent and reflective objects are the things of robot nightmares.

Roboticists at Carnegie Mellon University, however, report success with a new technique they've developed for teaching robots to pick up these troublesome objects. The technique doesn't require fancy sensors, exhaustive training or human guidance, but relies primarily on a color camera. The researchers will present this new system during this summer's International Conference on Robotics and Automation virtual conference.

David Held, an assistant professor in CMU's Robotics Institute, said depth cameras, which shine infrared light on an object to determine its shape, work well for identifying opaque objects. But infrared light passes right through clear objects and scatters off reflective surfaces. Thus, depth cameras can't calculate an accurate shape, resulting in largely flat or hole-riddled shapes for transparent and reflective objects.

But a color camera can see transparent and reflective objects as well as opaque ones. So CMU scientists developed a color camera system to recognize shapes based on color. A standard camera can't measure shapes like a depth camera, but the researchers nevertheless were able to train the new system to imitate the depth system and implicitly infer shape to grasp objects. They did so using depth camera images of opaque objects paired with color images of those same objects.

Once trained, the color camera system was applied to transparent and shiny objects. Based on those images, along with whatever scant information a depth camera could provide, the system could grasp these challenging objects with a high degree of success.

"We do sometimes miss," Held acknowledged, "but for the most part it did a pretty good job, much better than any previous system for grasping transparent or reflective objects."

The system can't pick up transparent or reflective objects as efficiently as opaque objects, said Thomas Weng, a Ph.D. student in robotics. But it is far more successful than depth camera systems alone. And the multimodal transfer learning used to train the system was so effective that the color system proved almost as good as the depth camera system at picking up opaque objects.

"Our system not only can pick up individual transparent and reflective objects, but it can also grasp such objects in cluttered piles," he added.

Other attempts at robotic grasping of transparent objects have relied on training systems based on exhaustively repeated attempted grasps -- on the order of 800,000 attempts -- or on expensive human labeling of objects.

The CMU system uses a commercial RGB-D camera that's capable of both color images (RGB) and depth images (D). The system can use this single sensor to sort through recyclables or other collections of objects -- some opaque, some transparent, some reflective.

CORVALLIS, Ore. - Caspian terns feeding on young fish have a significant impact on runs of steelhead in the Columbia River, research by Oregon State University suggests.

Through detailed analysis of steelhead survival and Caspian tern predation rates, the researchers found that the birds are not only preying on fish that would perish for some other reason, but are adding to the annual death toll by eating steelhead smolts that would have survived without tern pressure.

In scientific terms, the findings indicate that the terns are having an "additive" effect on prey mortality rather than a "compensatory" one.

The study was published in Ecological Applications.

In the Columbia Basin, 13 of 20 populations of anadromous salmon and steelhead are listed as threatened or endangered under the Endangered Species Act. Caspian terns, a protected migratory bird species native to the region, have been the object of predator management in the Columbia Basin in an effort to protect smolts, especially steelhead smolts, from being eaten before they can swim downstream to the ocean.

The largest breeding colony of Caspian terns in the world was formerly on a small island in the lower Columbia River estuary between Oregon and Washington. It hosted more than 10,000 breeding pairs in 2008, just prior to implementation of nonlethal management to reduce colony size to between 3,125 and 4,375 breeding pairs.

"There has been little research, however, into whether reduced predation actually results in greater overall salmonid survival, either at the smolt stage, where the predation is taking place, or across the lifetime of the fish," said Oregon State's Dan Roby, professor emeritus in the Department of Fisheries and Wildlife of the College of Agricultural Sciences. "Without clear evidence that reduced predation means greater survival to adulthood, management to reduce predator impacts would be a waste of time and resources."

To tackle the question, Roby and collaborators at Real Time Research, Inc., of Bend and the University of Washington looked at 11 years' worth of mark-recapture-recovery data for almost 80,000 steelhead trout smolts from the Upper Columbia population that were tagged and released to continue their out-migration to the ocean.

After release, the tagged fish were exposed to predation throughout multiple stretches of river on their journey toward the Pacific. The tag-recovery data made possible estimates of the weekly probability of steelhead survival, mortality from being eaten by birds and death from other causes.

"This approach allowed us to directly measure the connection between smolt survival and tern predation," Roby said.

Estimates of tern predation on steelhead were substantial for most of the years studied, he said. And increases in tern predation probabilities were connected with statistically significant decreases in steelhead survival for all of the years evaluated and both of the fish life stages studied: smolt out-migration and smolt-to-adult returns.

"Our results provide the first evidence that predation by Caspian terns may have been a super additive source of mortality during the smolt stage and a partially additive source in the smolt-to-adult life stage," Roby said. "A persistent pattern was clear: For each additional 10 steelhead smolts successfully consumed by Caspian terns, about 14 fewer smolts from each cohort survived out-migration."

Another pattern: On average, for every 10 steelhead smolts eaten by terns, one fewer individual from each cohort returned to the Columbia Basin as an adult.

"Our model shows that mortality from tern predation was primarily additive and therefore has a credible, significant impact on prey survival," Roby said. "Predator-prey models need to consider additive effects of predation across life stages to avoid exaggerating potential benefits from management actions aimed at reducing predator populations to enhance prey populations. The primary value of the study is by analyzing the true effects of natural predators on populations of their prey, and thereby assessing the conservation value to prey of managing predators."

Roby notes that the study by OSU, Real Time Research, and the University of Washington contradicts recently published research by scientists with the U.S. Fish and Wildlife Service and the Fish Passage Center, who found that steelhead mortality due to tern predation is compensatory.

That paper, in the Journal of Wildlife Management, suggests that "management efforts to reduce the abundance of the [tern] colonies are unlikely to improve the survival or conservation status of steelhead."

Various pro-inflammatory cytokines and pathogen-associated molecular patterns such as lipopolysaccharide (LPS) are known to activate NF-kB. NF-kB is a master regulator of inflammation and induces pro-inflammatory cytokines. Although LPS-induced pro-inflammatory cytokiens are indispensable for host defense against pathogens, dysregulated production can lead to septic shock. Septic shock is the most common cause of death in intensive care unit. Pro-inflammatory cytokines in a systemic scale inflammatory response result in increased capillary permeability and low blood pressure. However, despite injection of anti-pro-inflammatory cytokine antibody into human septic shock, mortality rates remain high. Other than pro-inflammatory cytokines, macrophages can secrete vascular endothelial growth factor (VEGF) in response to LPS. VEGF was initially described as a stimulator of endothelial permeability. VEGF was subsequently reported to promote proliferation and survival of endothelial cells, and is now thought to be the pivotal regulator of angiogenesis and vascular leakage. Notably, VEGF exaggerates septic inflammation, and human serum VEGF level can be used as a predictor of septic prognosis. Thus, not only pro-inflammatory cytokines but also VEGF play critical roles for septic pathophysiology. Recently, Suppression of tumorigenicity 18 (St18) was discovered as a putative regulator of pro-inflammatory cytokine signaling. St18 is also reported as a candidate tumor suppressor in human breast tumors, because its expression is significantly down regulated in these cells compared to normal breast tissues. Conversely, St18 expression is up regulated in liver cancers, indicating an oncogenic function of this gene. Despite the pleiotropic functions of St18 in cancers, little is known about its functions in myeloid lineages. Maruyama and colleagues discovered that St18 is expressed in myeloid cells. Unexpectedly, mice lacking St18 in myeloid lineages exhibit increased retinal vasculature with enhanced serum VEGF concentrations, and pharmacological inhibition of VEGF signaling rescued the high mortality rate of septic shock. Mechanistically, St18 bound to Sp1 and attenuated its activity, leading to the suppression of Sp1 target gene VEGF. Thus, myeloid St18-mediated gene regulation may be a promising strategy for the development of therapeutics to control VEGF-associated disorders.

A new spin on the magnetic compression of plasmas could improve materials science, nuclear fusion research, X-ray generation and laboratory astrophysics, research led by the University of Michigan suggests.

The study shows that a spring-shaped magnetic field reduces the amount of plasma that slips out between the magnetic field lines.

Known as the fourth state of matter, plasma is a gas so hot that electrons rip free of their atoms. Researchers use magnetic compression to study extreme plasma states in which the density is high enough for quantum mechanical effects to become important. Such states occur naturally inside stars and gas giant planets due to compression from gravity.

The research group led by Ryan McBride, an associate professor of nuclear engineering and radiological sciences at U-M, tests ways to achieve states like this by imploding plasma cylinders with magnetic fields. These cylinders have a tendency to break up in a "sausage link" fashion when the magnetic field finds tiny divots in the cylinder's surface and cuts into them. (The technical term is "sausage instability.")

"It's like trying to squeeze a stick of soft butter with your hands," said McBride. "The butter squishes out between your fingers."

The butter in McBride's analogy is plasma and the fingers are magnetic field lines. His group looked for a way to keep the magnetic field from digging into the imperfections in the cylinder, instead causing the field to press more uniformly on the cylinder's outer surface. They did this by twisting the magnetic field into a helix, that spring-like shape, and varying the angle at which the helix pressed on the plasma cylinder. This made it harder for the magnetic field to slice in--the field moved across many divots rather than pressing into any one divot for too long.

The most twisted magnetic configurations tested in these experiments reduced the length of the escaping plasma tentacles by about 70%. The research was done in collaboration with Sandia National Laboratories and the Laboratory of Plasma Studies at Cornell University.

The team changed the shape of the magnetic field by changing the way that the electrical current--over 1 million amperes--ran through the compression device. The electrical current typically runs up through the central cylinder that is to be compressed and then back down through straight "return current" columns that surround the central cylinder. This produces a cylindrical magnetic field that surrounds the central cylinder. To transform the cylindrical field into a helix, the team twisted the return-current columns around the central cylinder. The central cylinder starts out as a metal foil, but the huge electrical current quickly transforms the metal into a plasma. They ran the experiments on the Cornell Beam Research Accelerator.

"Designing the return current structures was an interesting balancing act," said Paul Campbell, first author on the paper and a Ph.D. student in nuclear engineering and radiological sciences at U-M. "We weren't sure we could even get these structures machined, but fortunately, metal 3D printing has advanced far enough that we were able to get them printed instead."

Campbell explained that when the structures are more twisted, less current runs through them, so the columns had to be placed closer to the imploding plasma to compensate. At the same time, they needed gaps in the structure so that they could see what was going on with the implosion.

In line with replicating the conditions inside stars, magnetic compression is a method for compressing nuclear fusion fuel--typically variants of hydrogen--to study the processes that power stars. The technique can also generate powerful X-ray bursts and simulate astrophysical phenomena such as plasma jets near black holes.

A paper on this research, "Stabilization of liner implosions via a dynamic screw pinch," is accepted by the journal Physical Review Letters. The research will also be featured in an invited talk at the annual conference of the American Physical Society's Division of Plasma Physics in November 2020.