The team proposed a method to generate entangled photons at extreme-ultraviolet (XUV) wavelengths where no such source currently exists. Their work provides a road map on how to generate these entangled photons and use them to track the dynamics of electrons in molecules and materials on the incredibly short timescales of attoseconds.

“The entangled photons in our work are guaranteed to arrive at a given location within a very short duration of attoseconds, as long as they travel the same distance,” says Dr. Niranjan Shivaram, assistant professor of Physics and Astronomy. “This correlation in their arrival time makes them very useful to measure ultrafast events. One important application is in attosecond metrology to push the limits of measurement of the shortest time scale phenomena. This source of entangled photons can also be used in quantum imaging and spectroscopy, where entangled photons have been shown to enhance the ability to gain information, but now at XUV and even X-ray wavelengths.”

The authors of the publication, titled “Attosecond entangled photons from two-photon decay of metastable atoms: A source for attosecond experiments and beyond,” are all from the Purdue University Department of Physics and Astronomy and work with the Purdue Quantum Science and Engineering Institute (PQSEI). They are Dr. Yimeng Wang, recent graduate of Purdue University; Siddhant Pandey, PhD candidate in the field of experimental ultrafast spectroscopy; Dr. Chris H. Greene, Albert Overhauser Distinguished Professor of Physics and Astronomy; and Dr. Shivaram.

“The Department of Physics and Astronomy at Purdue has a strong atomic, molecular and optical (AMO) physics program, which brings together experts in various subfields of AMO,” says Shivaram. “Chris Greene’s expert knowledge of theoretical atomic physics combined with Niranjan’s background in the relatively young field of experimental attosecond science led to this collaborative project. While many Universities have AMO programs, Purdue’s AMO program is uniquely diverse in that it has experts in multiple subfields of AMO science.”

Each researcher played a significant role in this ongoing research. Greene initially suggested the idea of using photons emitted by helium atoms as a source of entangled photons and Shivaram suggested applications to attosecond science and proposed experimental schemes. Wang and Greene then developed the theoretical framework to calculate entangled photon emission from helium atoms, while Pandey and Shivaram made estimates of entangled photon emission/absorption rates and worked out the details of the proposed attosecond experimental schemes.

The publication marks the beginning of this research for Shivaram and Greene. In this publication, the authors propose the idea and work out the theoretical aspects of the experiment. Shivaram and Greene plan to continue to collaborate on experimental and further theoretical ideas. Shivaram’s lab, the Ultrafast Quantum Dynamics Group, is currently building an apparatus to experimentally demonstrate some of these ideas. According to Shivaram, the hope is that other researchers in attosecond science will begin working on these ideas. A concerted effort by many research groups could further increase the impact of this work. Eventually, they hope to get the timescale of entangled photons down to the zeptosecond, 10^-21 seconds.

“Typically, experiments on attosecond timescales are performed using attosecond laser pulses as ‘strobes’ to ‘image’ the electrons. Current limits on these pulses are around 40 attoseconds. Our proposed idea of using entangled photons could push this down to a few attoseconds or zeptoseconds,” says Shivaram.

In order to understand the timing, one must understand that electrons play a fundamental role in determining the behavior of atoms, molecules and solid materials. The timescale of motion of electrons is typically in the femtosecond (one millionth of a billionth of a second — 10^-15 seconds) and attosecond (one billionth of a billionth of a second, or 10^-18 seconds) scale. According to Shivaram, gaining insight into the dynamics of electrons and tracking their motion on these ultrashort timescales is essential.

“The goal of the field of ultrafast science is to make such ‘movies’ of electrons and then use light to control the behavior of these electrons to engineer chemical reactions, make materials with novel properties, make molecular-scale devices, etc.,” he says. “This is light-matter interaction at its most basic level, and the possibilities for discovery are many. A single zeptosecond is 10^-21 seconds. A thousand zeptoseconds is an attosecond. Researchers are only now beginning to explore zeptosecond phenomena, though it is experimentally out of reach due to lack of zeptosecond laser pulses. Our unique approach of using entangled photons instead of photons in laser pulses could allow us to reach the zeptosecond regime. This will require considerable experimental effort and is likely possible on the timescale of five years.”

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Materials provided by Purdue University. Original written by Cheryl Pierce. Note: Content may be edited for style and length.

Human clinical trials of the drug, an antiparasitic compound known as AN15368, will hopefully begin in the next few years.

“I’m very optimistic,” said Rick Tarleton, corresponding author of the study and a UGA Athletic Association Distinguished Professor in the Franklin College of Arts and Sciences. “I think it has a really strong chance of being a real solution, not just a stand-in for something that works better than the drugs we currently have.”

The new drug works by targeting the parasite that causes the disease, Trypanosoma cruzi, also known as T. cruzi.

Nearly all people infected with the parasite experience flu-like symptoms such as fever, headaches and vomiting. However, after their immune response kicks in, their symptoms may subside.

But for 30% to 40% of patients, the infection can result in severe heart damage that can be both debilitating and life-threatening.

New drug is 100% effective in eliminating T. cruzi

Published in Nature Microbiology, the study found the new medication was 100% effective in curing mice, as well as non-human primates that were naturally infected by the parasite at a research facility in Texas. The animals also experienced no significant side effects from exposure to the drug.

Over the past several decades, previous treatment candidates went straight from experimental infections in mice to human clinical trials, where they failed to cure the infection. The new drug’s efficacy in non-human primates bodes well for how it will perform in humans.

“We’ve got something that is as close to effective as it can be in what is as close to a human as it could be, and there aren’t any side effects. That really de-risks it by a lot going into humans,” Tarleton said. “It doesn’t make it fail-safe, but it moves it much further along.”

Current medications to treat T. cruzi infection not ideal

T. cruzi is carried by blood-sucking insects known as kissing bugs. The insects can be found throughout North, Central and South America.

In addition to a nasty bite, the creatures carry the T. cruzi parasite, which is transmitted through their fecal matter. Victims can become infected when they unknowingly rub the insect’s feces into their eyes, nose or an open wound.

The infection may also be transmitted through organ transplants, from a pregnant person to their fetus or through contaminated food. However, infections from these pathways are less common.

The go-to medications used to treat Chagas aren’t terrible, Tarleton said, but they’re not ideal. They can pack some serious side effects and they’re not reliably effective, but they’re currently the only treatment option.

Patients also have to take the drugs for two months. And even the common but mild side effects like headache or nausea get old after a few weeks. As a result, about one in five people being treated for the disease stop taking their medications before they have a chance to cure the infection.

“Plus they have variable efficacy, and it’s not predictable,” Tarleton said. “I think most physicians in Latin America have to say, ‘We have a drug. It’s going to make you feel bad, and two months later after we finish it, we’re not really going to be able to tell you if it worked or not.’

“It’s really not a good inducement to take the medication.”

Chagas disease common in Latin American countries

Tens of millions of people across the Americas are infected with the parasite that causes Chagas disease. But it doesn’t get much media attention.

It’s most common in Latin American countries, particularly in low-income areas where housing isn’t ideal. Some of the countries with the highest rates of the disease include Bolivia, Venezuela, Argentina, Chile, Mexico and Brazil.

In homes with thatched roofs, mud walls or inadequate protection from the elements, kissing bugs thrive, making infection more likely.

Chagas disease poses significant risk to pets

The Centers for Disease Control and Prevention estimates around 300,000 people infected with the parasite currently live in the U.S. But because the condition isn’t a huge threat in places with good housing options, Chagas disease treatment and prevention doesn’t get much research funding.

There is growing concern about the T. cruzi infection rate among outdoor pets in the U.S., however. Working dogs and other pets that spend extended periods of time outside are contracting the parasite at an alarming rate.

“There are areas where the infection rates are 20% to 30% new infections per year,” Tarleton said. “Those tend to be severe infections where the dogs either die or develop a disease that makes them unable to work.”

Tarleton hopes to partner with veterinary pharmaceutical companies in the future to create a drug to treat the infection in pets as a means of funding diagnostics and medication purchases in Latin America.

For the present study, Tarleton partnered with colleagues at Anacor Pharmaceuticals, Texas A&M University, the University of Texas, the University of Kansas and Pfizer. Angel Padilla, Wei Wang, Dylan Orr, Brooke White, Arlene George and Huifeng Shen from UGA’s Center for Tropical and Emerging Global Diseases and the Department of Cellular Biology are co-authors on the paper.

Treatment of cancer is a long-term process because remnants of living cancer cells often evolve into aggressive forms and become untreatable. Hence, treatment plans often involve multiple drug combinations and/or radiation therapy in order to prevent cancer relapse. To combat the variety of cancer cell types, modern drugs have been developed to target specific biochemical processes that are unique within each cell type.

However, cancer cells are highly adaptive and able to develop mechanisms to avoid the effects of the treatment. “We want to prevent such adaptation by invading the main pillar of cellular life — how cells breathe — that means take up oxygen — and thus produce chemical energy for growth,” says David Ng, group leader at the MPI-P.

The research team produced a synthetic drug that travels into cells where it reacts to conditions found inside and triggers a chemical process. This allows the drug’s molecules to bind together and form tiny hairs that are a thousand times thinner than human hair. “These hairs are fluorescent, so you can look at them directly with a microscope as they form,” says Zhixuan Zhou, an Alexander-von-Humboldt-fellow and first author of the paper.

The scientists monitored the oxygen consumption in different cell types and found that the hairs stop all of them from converting oxygen into ATP, a molecule that is responsible for energy delivery in cells. The process worked even for those cells derived from untreatable metastatic cancer. As a result, the cells die rapidly within four hours. After some more years of research, the scientists hope that they can develop a new method to treat up-to-now untreatable cancer.

Weil, Ng and colleagues have shown an exciting outcome under controlled laboratory culture and will continue to unravel deeper insights on the basis of how these tiny hairs prevent the conversion of oxygen to chemical energy. With further development, these objects could in the future possibly also be manipulated to control other cellular processes to address other important diseases.

They have published their results in the Journal of the American Chemical Society.

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Materials provided by Max Planck Institute for Polymer Research. Note: Content may be edited for style and length.

A convolutional neural network is a deep learning neural network designed for processing structured arrays of data such as images. Such advancements in deep learning have fundamentally changed the way tasks, like architectural segmentation, are performed. However, an accurate deep convolutional neural network (DCNN) model needs a large volume of labeled training data and labeling these data can be a slow and extremely expensive manual undertaking.

To create the synthetic digital city twin data, the investigators used a 3D city model from the PLATEAU platform, which contains 3D models of most Japanese cities at an extremely high level of detail. They loaded this model into the Unity game engine and created a camera setup on a virtual car, which drove around the city and acquired the virtual data images under various lighting and weather conditions. The Google Maps API was then used to obtain real street-level images of the same study area for the experiments.

The researchers found that the digital city twin data leads to better results than purely virtual data with no real-world counterpart. Furthermore, adding synthetic data to a real dataset improves segmentation accuracy. However, most importantly, the investigators found that when a certain fraction of real data is included in the digital city twin synthetic dataset, the segmentation accuracy of the DCNN is boosted significantly. In fact, its performance becomes competitive with that of a DCNN trained on 100% real data. “These results reveal that our proposed synthetic dataset could potentially replace all the real images in the training set,” says Tomohiro Fukuda, the corresponding author of the paper.

Automatically separating out the individual building facades that appear in an image is useful for construction management and architecture design, large-scale measurements for retrofits and energy analysis, and even visualizing building facades that have been demolished. The system was tested on multiple cities, demonstrating the proposed framework’s transferability. The hybrid dataset of real and synthetic data yields promising prediction results for most modern architectural styles. This makes it a promising approach for training DCNNs for architectural segmentation tasks in the future — without the need for costly manual data annotation.

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The measurements and analyses of coronavirus levels in the wastewater of Gothenburg attracted a great deal of attention during the pandemic. The weekly reports have shown both how widespread SARS-CoV-2 infection is in the community and its distribution among variants of the virus.

Beginning in February 2020, the virus measurements taken in the monitoring rapidly became a useful indicator for forecasting load peaks in health care. High concentrations of SARS-CoV-2 in the wastewater were followed by rising numbers of people with COVID-19 needing hospitalization.

The association emerges with striking precision in the study now published in the scientific journal iScience. Each of the four pandemic waves in 2020-2022 exhibits a pattern in which, within a couple of weeks after SARS-CoV-2 peaked in the wastewater, a rise in the number of newly admitted hospital patients with COVID-19 ensued.

Increased pressure on 1177 Vårdguiden

The virus peaks in the wastewater were followed not only by heavier burdens on inpatient care, but also by predictable increases in pressure on the 1177 Vårdguiden e-service. One to two weeks after a wastewater virus peak, more calls were coming in about acute breathlessness in adults.

“The study shows that virus monitoring in wastewater can predict how a pandemic is going to develop and its burden on several parts of the health system,” says Hao Wang, postdoctoral researcher at Sahlgrenska Academy’s Department of Infectious Diseases, University of Gothenburg, and the study’s first author.

The study provides an account of the degree of testing capacity in Sweden during various phases of the pandemic. The scientists say that the national statistics on the number of confirmed cases did not reflect the actual spread of infection.

However, even when their symptoms were mild, all those infected had the virus in their urine and feces. This enabled detection of the virus in wastewater, in the form of RNA (genetic material). The weekly reports were based on daily samples of wastewater collected by Gryaab, the municipal water treatment company in Gothenburg.

Lasting benefit to community

Heléne Norder, research leader at the University of Gothenburg’s Sahlgrenska Academy and the last author of the study, sees the results as proof of how virus surveillance during the pandemic has benefited the community. She also identifies the distinct advantages of the method used.

“The method we use in Gothenburg also enables monitoring of other viruses, which gives us unique scope for quickly spotting ongoing outbreaks. In the area, besides SARS-CoV-2, we’ve also been able to demonstrate the presence of viruses that spread through food or water and are excreted in the feces. Some of those caused outbreaks — norovirus, the ‘winter vomiting bug’, and astrovirus among children, for instance — during the pandemic.

“So, during that time,” she continues, “we found changes in the virus levels that were directly relatable to the number of people infected in Gothenburg. Our research group intends to keep analyzing different viruses in the wastewater as long as we have research funding for it.”

The planning also includes further development of the technique to enable its adoption by all the laboratories that wish to carry out continuous virus monitoring.

“This might result in monitoring of more viruses in more regions for rapid identification of future outbreaks and efficient, proactive nationwide surveillance of ongoing ones,” Norder concludes.

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Materials provided by University of Gothenburg. Note: Content may be edited for style and length.

Animals, especially endangered and threatened species, are often exploited and sold for their pelts or used as medicine, aphrodisiacs, curios, food and spiritual artifacts.

In a new study published in Global Change Biology, Arizona State University researchers estimate that more than 1.1 million sea turtles have been illegally killed and, in some cases, trafficked between 1990 and 2020. Even with existing laws prohibiting their capture and use, as many as 44,000 sea turtles were exploited each year over the past decade in 65 countries or territories and in 44 of the world’s 58 major sea turtle populations.

Despite the seemingly large number of poached turtles, the study shows that the reported illegal exploitation of sea turtles declined by approximately 28% over the last decade — something that surprised the researchers. They initially expected to see an overall increase in reported poaching.

“The decline over the past decade could be due to increased protective legislation and enhanced conservation efforts, coupled with an increase in awareness of the problem or changing local norms and traditions,” says Kayla Burgher, co-first author of the study and a doctoral student in ASU’s environmental life sciences program in the School of Life Sciences.

In addition to the slight decline, the researchers found that most of the reported illegal exploitation over the past decade occurred in large, stable and genetically diverse sea turtle populations.

Jesse Senko, co-first author of the study and an assistant research professor with the ASU School for the Future of Innovation in Society says this discovery may be a silver lining to the high number of turtles illegally exploited. “What this means is that most of these sea turtles came from healthy, low-risk populations, which suggests that, with a few exceptions, current levels of illegal exploitation are likely not having a major detrimental impact on most major sea turtle populations throughout the world’s oceans.”

Senko adds, however, the results should be cautiously considered. “Assessing any illegal activity is difficult, and the take and trade of sea turtles is no exception, especially when it becomes organized or connected to crime syndicates. Our assessment also did not include eggs or turtle products, such as bracelets or earrings made from sea turtle shells that could not be easily attributed to individual turtles,” says Senko.

In the study, the researchers reviewed data from peer-reviewed journal articles, archived media reports, NGO reports, and online questionnaires to determine a comprehensive look at existing information on exploited sea turtles. The study revealed additional patterns and trends that may assist in determining conservation management priorities. For example, Vietnam was the most common country of origin for illegal sea turtle trafficking, while China and Japan served as destinations for nearly all trafficked sea turtle products. Similarly, Vietnam to China was the most common trade route across all three decades.

Across the 30-year study period, 95% of poached sea turtles came from two species — green and hawksbill turtles — both of which are listed under the U.S. Endangered Species Act. Also, Southeast Asia and Madagascar emerged as major hotspots for illegal sea turtle take and trade, particularly for critically endangered hawksbills, which are prized in the illicit wildlife trade for their beautiful shells.

“Our assessment is an important foundation for future research and outreach efforts regarding illegal sea turtle exploitation. We believe this study can help conservation practitioners and legislators prioritize conservation efforts and allocate their resources to best help protect sea turtle populations from harmful levels of exploitation worldwide,” says Burgher.

The research team says much more needs to be done to sustain global biodiversity.

“Increased support for governments lacking the resources to protect sea turtles is needed, along with support for communities to sustain human well-being in the face of restrictions or bans on sea turtle exploitation. We must develop conservation strategies that benefit both people and turtles,” says Senko.