How a photodetector will diagnose urinary infections faster

A fast and accurate way to diagnose urinary tract infections, a puzzling discovery about the sun, and more in this edition of Science Notebook.

The High Altitude Water Cherenkov Observatory in Mexico. | Photo Credit: Jordon Goodman/HAWC Collaboration Study

Researchers at the Chemical Engineering Department of the Indian Institute of Technology Guwahati, working in collaboration with Altanostics Labs Pvt. Ltd, IITG Research Park, have developed a fast, accurate, and reliable diagnostic device to detect the bacteria that cause urinary tract infections (UTIs). The estimated cost of manufacturing it is Rs.608, and testing a single sample will only cost Rs.8. UTIs are prevalent worldwide mostly in women. The conventional way to diagnose is by urine culture, which takes a minimum of two days. Identification of the specific bacterium causing the infection is important for appropriate treatment.

The device is a photodetector that detects and quantifies a specific bacterium called Klebsiella pneumoniae within five minutes from a patient’s urine sample. The developed prototype is stated to be generic and can be tuned to detect other UTI-causing bacteria as well. The results obtained using the photodector matched well with those obtained using conventional methods, the IITG press release said. The work, led by Partho Sarathi Gooh Pattader, was funded by the Indian Council of Medical Research, the Science and Engineering Research Board, and the Ministry of Electronics & Information Technology and was published in the journal ACS Applied Bio Materials.

New light on the quiescent sun

By analysing more than six years of data from the High Altitude Water Cherenkov Observatory in Mexico, researchers from the HAWC collaboration detected for the first time gamma-ray light with energies in the tera electronvolt range from the sun. This is the highest-energy light ever detected from the sun and indicates that the sun is brighter in this energy range than current models can explain. This puzzling discovery deepens mysteries about solar-disk emission and suggests that models of galactic cosmic ray interactions with nuclei in the solar atmosphere need a revision. The finding was reported in Physical Review Letters.

Seeing the cosmos with neutrinos

An artist’s composition of the Milky Way seen with a neutrino lens (blue).  | Photo Credit: IceCube Collaboration/U.S. National Science Foundation (Lily Le & Shawn Johnson)/ESO (S. Brunier)

For the first time, the IceCube Neutrino Observatory, a gigaton detector located under the Antarctic ice (Frontline, June 27, 2014), has produced an image of the Milky Way by measuring cosmic emissions of neutrinos, ghost-like, almost massless, and very feebly interacting particles. In an article published in a recent issue of Science, the international IceCube Collaboration presented evidence of high-energy neutrino emissions from the Milky Way. IceCube searches for signs of high-energy neutrinos originating from our galaxy and beyond, out to the farthest reaches of the universe. IceCube has in the past decade detected neutrinos with energies millions to billions of times higher than those produced by the fusion reactions that power stars. “What’s intriguing is that, unlike the case for light of any wavelength, in neutrinos, the universe outshines the nearby sources in our own galaxy… making it easier for us to detect neutrinos from distant sources than the Milky Way,” said Francis Halzen of the University of Wisconsin-Madison, IceCube’s principal investigator.

Interactions between cosmic rays and galactic gas and dust inevitably produce both gamma rays and neutrinos. Given the observation of gamma rays from the galactic plane, the Milky Way was expected to be a source of high-energy neutrinos. The neutrino counterpart has now been measured. The dataset used in the study included 60,000 neutrinos spanning 10 years of IceCube data, 30 times as many events as the selection used in a previous analysis of the galactic plane. “Observing our own galaxy for the first time using particles instead of light is a huge step,” said Naoko Kurahashi Neilson of Drexel University, IceCube member. “As neutrino astronomy evolves, we will get a new lens with which to observe the universe.”

COVID virus has an alternative way to enter cells

SARS-CoV-2, the virus that causes COVID-19, is known to infect many cells and tissues. This characteristic of pathogens, known as “tissue tropism”, is often determined by the availability of a range of entry receptors on host cells. Until now, the angiotensin-converting enzyme 2 (ACE2) was the well-known main receptor of COVID. In a study, published in the journal Cell, scientists from Leuven (Belgium) and London, led by Jim Baggen of the Rega Institute, Leuven, showed that a lysosomal transmembrane protein, TMEM106B, could serve as a receptor for SARS-CoV-2’s entry into cells without ACE2. It was found to engage directly with the receptor-binding domain of the spike protein (in the same position range of the S1 subunit as ACE2) on the virus and functions as an alternative receptor for the virus. These findings show that SARS-COV-2 can infect a much wider range of tissues in humans, including those that lack ACE2.

Greenhouse gases may stop Atlantic ocean currents

The Atlantic Meridional Overturning Circulation is critical for the redistribution of heat from the tropics to the northern parts of the Atlantic.   | Photo Credit: Niels Bohr University/Copenhagen University/Getty Image

Researchers from the University of Copenhagen’s Niels Bohr Institute and Department of Mathematical Sciences predict that the Atlantic Meridional Overturning Circulation (AMOC), the large system of ocean currents that distributes cold and warm water between the North Atlantic region and the tropics, will completely stop if humans continue to emit the same levels of greenhouse gases as at present. Using advanced statistical tools and ocean temperature data over the last 150 years, the researchers calculated that the AMOC is most likely to collapse (with 95 per cent probability) by mid-century. This could result in greater warming in the tropics and increased storminess in the North Atlantic region. “Shutting down the AMOC can have very serious consequences for the earth’s climate, for example, by changing how heat and precipitation are distributed globally,” said Peter Ditlevsen, one of the two authors of the paper, which was published in Nature Communications. The strength of the AMOC has only been monitored continuously since 2004, and these observations showed that it is weakening. Longer records are needed to assess the magnitude of this change. Contrary to this study, recent assessments by the Intergovernmental Panel on Climate Change suggest that a full collapse of the AMOC is unlikely within the 21st century.