[ad_1]
Newswise — Billions of years ago, Earth was an extremely hostile planet with active volcanoes, a harsh atmosphere, and certainly no life! This prebiotic Earth, however, was filled with a wide array of abiotic organic molecules derived from its early environment, which underwent chemical reactions that eventually led to the origin of life. A class of such abiotic molecules abundant during the prebiotic era was the
[ad_2]
Tokyo Institute of Technology
Source link
[ad_1]
Newswise — After more than two years since its discovery, six million deaths, and half a billion reported cases, there is still no effective cure for COVID-19. Even though vaccines have lowered the impact of outbreaks, patients that contract the disease can only receive supportive care while they wait for their own body to clear the infection.
A promising COVID-19 treatment strategy that has been gaining traction lately is targeting angiotensin-converting enzyme 2 (ACE2). This is a receptor found on the cell membrane that allows entry of the virus into the cell due to its high affinity for SARS-CoV-2’s spike protein. The idea is that reducing the levels of ACE2 on the membrane of cells could be a way to prevent the virus from entering them and replicating, thereby lowering its infectious capabilities.
In a recent study published in PLOS ONE, a team of scientists including Associate Professor Shun-Ichiro Ogura from Tokyo Institute of Technology, Japan, analyzed the potential of a natural amino acid called 5-Aminolevulinic acid (ALA) to reduce the expression of ACE2. This research was performed in collaboration with SBI Pharmaceuticals Co. Ltd.
As the researchers explain in their paper, ALA had been identified in 2021 as a compound that seemed to reduce the infectivity of SARS-CoV-2. However, the underlying mechanisms that led to this phenomenon remained unknown, until now.
The team hypothesized that the results of the 2021 study could be explained by an effect of ALA on the expression of ACE2. To test their hypothesis, they prepared human cell cultures, administered ACE2 on some of them, and compared the levels of ACE2 in treated cells versus control cells. As expected, the amount of available ACE2 in treated cells was significantly lower than in control cells.
But the story doesn’t end there. Upon uptake, cells transform ALA into a molecule called protoporphyrin IX (PpIX) and subsequently into heme—a precursor of hemoglobin and other useful proteins. This hinted that the expression of ACE2 could be linked to the production of either of these compounds. Thus, the team checked the levels of PpIX and heme in cells treated with ALA. “We observed significant increases in the concentration of intracellular PpIX, suggesting that ALA was uptaken into the cell and converted into PpIX,” remarks Ogura, “However, only a slight increase in heme concentration was observed, which might be due to the lack of an iron source to convert PpIX into heme.”
After introducing an iron source in the form of sodium ferrous citrate, the intracellular levels of heme increased significantly and the expression of ACE2 became even lower. These results suggest ACE2 expression is kept in check by heme production, the latter of which can be boosted by the co-administration of ALA and an iron source.
Overall, this study sheds light on how ALA and the heme production pathway could form the basis of a cure for COVID-19. “We believe ALA could be developed into a potential anti-viral agent for SARS-CoV-2, which may play an important role in the eradication of the disease in a global scale in the near future,” concludes Dr. Ogura.
Let us hope further studies can help us put an end to COVID-19 soon!
[ad_2]
Tokyo Institute of Technology
Source link
[ad_1]
Newswise — A database updated in 2022 reported around 4,852 active satellites orbiting the earth. These satellites serve many different purposes in space, from GPS and weather tracking to military reconnaissance and early warning systems. Given the wide array of uses for satellites, especially in low Earth orbit (LEO), researchers are constantly trying to develop better ones. In this regard, small satellites have a lot of potential. They can reduce launch costs and increase the number of satellites in orbit, providing a better network with wider coverage. However, due to their smaller size, these satellites have lesser radiation shield. They also have a deployable membrane attached to the main body for a large phased-array transceiver, which causes non-uniform radiation degradation across the transceiver. This affects the performance of the satellite’s radio due to the variation in the strength of signal they can sense—also known as gain variation. Thus, there is a need to mitigate radiation degradation to make small satellites more viable.
Fortunately, a team of researchers led by Associate Professor Atsushi Shirane of Tokyo Institute of Technology (Tokyo Tech) have reported a novel phased array receiver strategy to reduce the effects of radiation degradation in these satellites. Their findings have been shared and published in the 2023 International Solid-State Circuits Conference. Dr. Shirane explains, “We propose a new phased array receiver strategy which involves on-chip distributed radiation sensors and current-sharing techniques. This helps to drastically reduce the effects of radiation degradation on the radio and power consumption.”
The team of researchers found out that in the conventional design of the phased-array transceiver on small satellites, the signal from the main lobe degraded by 3.1 dB in a year due to ionizing radiation. To solve this the researchers created a phased-array transceiver with on-chip distributed radiation sensors. These sensors can detect the gain variation between the chips of the antenna. This was combined with current-sharing techniques to mitigate the gain variation and thus reduce the impact of non-uniform ionizing radiation on the radio and power consumption. Upon testing this new strategy, the researchers found that it led to less than 10% of the typical gain variation seen in small satellites. The current sharing techniques also brought down the power consumption of the satellite to the lowest reported value. Overall, this strategy was able to reduce the main lobe degradation and bring down gain variation while using a minimal amount of power, solving two major problems faced by existing small satellites.
“Using the distributed on-chip radiation sensors and the current sharing techniques, we were able to drastically reduce the impact of radiation degradation and make the phased-array transceiver more energy efficient. This strategy,” concludes Dr. Shirane, “was found to be comparable to other state-of-the-art technologies at reducing gain variation. Thus, we believe that given its performance and efficiency, our strategy may lead to an even greater number of small satellites in lower Earth orbit, and a more well-connected world.”
We have our fingers crossed for this future!
[ad_2]
Tokyo Institute of Technology
Source link
[ad_1]
Newswise — In light of vehicular pollutants contributing to decreasing air quality, governments across the globe are posing stricter emission regulations for automobiles. This calls for the development of more efficient exhaust gas after-treatment systems (i.e., systems to “clean” exhaust gas before it is released into the atmosphere). The most common mode for treating exhaust emissions of gasoline-fueled internal combustion engines are three-way catalysts (TWCs) or catalytic converters. TWCs often comprise active metals such as platinum (Pt) and palladium (Pd) nanoparticles and oxygen storage materials with a high specific surface area, such as a solid solution of CeO2-ZrO2(CZ). These components can catalyze multiple oxidation and reduction reactions that can convert harmful exhaust from vehicular engines to harmless gases.
The durability, precision, and performance of a TWC is dependent on factors like the oxygen stored or removed from the bulk and surface of the oxygen storage materials. So, clearly understanding the oxygen transport and dynamics of the storage material is necessary to improve its efficiency. Unfortunately, there is a lack of techniques that can enable direct tracking of the oxygen storage process in TWCs.
In a recent breakthrough published in Chemical Engineering Journal, however, a team of researchers led by Assistant Professor Tsuyoshi Nagasawa of Tokyo Institute of Technology (Tokyo Tech) presented a solution to the problem. The team developed a novel technique for direct visualization of the oxygen storage process in Pd/CZ TWCs using the isotope quenching technique. Prof Nagasawa explains: “It is difficult to get clarity on the dynamic interactions—such as oxygen adsorption/desorption and surface/bulk diffusion—occuring on TWC surfaces, because they can only be estimated indirectly from the valence change of cerium in CZ, or the oxidation state of the noble metal. However, our method surpasses these problems by incorporating isotope labeling with reaction quenching, which allows us to investigate the oxygen storage processes by tracking the 18O isotope involved in these interactions.”
How was this isotope quenching technique carried out? The team prepared a model TWC consisting of a precious metal, Pd, and a dense CZ substrate, stored 18O2 in it at 600 °C, and then quenched the catalyst using two helium gas nozzles covered in a water cooling jacket. They then used high-resolution secondary-ion mass spectrometry to analyze the 18O distribution on the surface and bulk of Pd/CZ.
The results indicated that Pd improves the diffusion depth of 18O into CZ bulk, as well as its surface concentration. It further revealed that 18O was preferentially adsorbed at the Pd/CZ interface as compared to the Pd center, where its concentration was lower. Density functional theory calculations also agreed with these observations.
Finally, the team calculated the local oxygen release/storage rates by comparing 18O distribution and an oxygen release/storage simulation using a diffusion equation. They found that the local rates were comparable and consistent with conventional oxygen storage capacity measurements.
This new visualization process provides useful insights into the oxygen storage and release mechanisms in metal/oxygen materials systems and can be used to further investigate and improve the performance and efficiency of TWCs used for automobile exhaust treatment. “The volatile organic compounds and oxides of nitrogen and carbon commonly produced by combustion engines, if released without treatment, can not only cause breathing-related health issues but can also indirectly impact the acceleration of global warming. With our study, we wanted to contribute towards the world’s mission to achieve better emission practices,” concludes Prof. Nagasawa.
[ad_2]
Tokyo Institute of Technology
Source link
[ad_1]
Newswise — Chirality is the breaking of reflection and inversion symmetries. Simply put, it is when an object’s mirror images cannot be superimposed over each other. A common example are your two hands—while mirror images of each other, they can never overlap. Chirality appears at all levels in nature and is ubiquitous. In addition to static chirality, chirality can also occur due to dynamic motion including rotation. With this in mind, we can distinguish true and false chirality. A system is truly chiral if, when translating, space inversion does not equate to time reversal combined with a proper spatial rotation.
Phonons are quanta (or small packets) of energy associated with the vibration of atoms in a crystal lattice. Recently, phonons with chiral properties have been theorized and experimentally discovered in two-dimensional (2D) materials such as tungsten diselenide. The discovered chiral phonons are rotating—yet not propagating—atomic motions. But, truly chiral phonons would be atomic motions that are both rotating and propagating, and these have never been observed in three-dimensional (3D) bulk systems.
Now, a team of researchers led by scientists from Tokyo Institute of Technology (Tokyo Tech) have identified truly chiral phonons, both theoretically and experimentally. The team, led by Professor Takuya Satoh of the Department of Physics at Tokyo Tech, observed the chiral phonons in cinnabar (α-HgS). This was achieved using a combination of first-principles calculations and an experimental technique called circularly polarized Raman scattering. “Chiral structures can be probed using chiral techniques. So, using circularly polarized light, which has its own handedness (i.e., right-handed or left-handedness), is critical. Dynamic chiral structures can be mapped using pseudo-angular momentum (PAM). Pseudo-momentum and PAM originate from the phase factors acquired by discrete translation and rotation symmetry operations, respectively,” explains Professor Satoh.
The researchers’ novel experimental approach also allowed them to probe the fundamental traits of PAM. They found that the law of the conservation of PAM—one of the key laws of physics—holds between circularly polarized photons and chiral phonons. “Our work also provides an optical method to identify the handedness of chiral materials using PAM. Namely, we can determine the handedness of materials with better resolution than x-ray diffraction (XRD) can achieve. Moreover, XRD requires a large-enough crystal, is invasive, and can be destructive. Circularly polarized Raman scattering, on the other hand, allowed us to determine the chirality of structures XRD could not, in a non-contact and non-destructive manner,” concludes Professor Satoh.
This study is the first to identify truly chiral phonons in 3D materials, which are clearly distinct from those seen previously in 2D hexagonal systems. The learnings gained here could drive new research into developing ways for transferring the PAM from photons to electron spins via propagating chiral phonons in future devices. Furthermore, this approach enables the determination of the true chirality of a crystal in an improved manner, providing a new critical tool for experimentalists’ and researchers.
[ad_2]
Tokyo Institute of Technology
Source link