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Tag: Hiroshima University

Neural network model helps predict site-specific impacts of earthquakes

Posted on by Hiroshima University

A new study published by Hiroshima University (HU) researchers in the Bulletin of the Seismological Society of America introduced a novel AI-based technique for estimating site amplification factors (AF) from data on microtremors of the ground.

Subsurface soil conditions, which determine how earthquakes affect a site, vary substantially. Softer soils, for example, tend to amplify ground motion from an earthquake, while hard substrates may dampen it. Ambient vibrations of the ground or microtremors can be used to investigate soil conditions. Measuring microtremors provides valuable information about the AF of a site, thus its vulnerability to earthquake damage.

“The proposed method would contribute to more accurate and more detailed seismic ground motion predictions for future earthquakes,” said lead author and HU Associate Professor Hiroyuki Miura.

The study used 2012-2020 microtremor data from 105 sites in western Japan’s Chugoku district. The model performed well on the test data, demonstrating its potential as a predictive tool for characterizing site AF from microtremor data.

DOI: 10.1785/0120210300

Broccoli compound induces cell death in yeast, offers research path for cancer treatment

Posted on by Hiroshima University

Broccoli may contain advantages beyond nutrition. A molecule found in broccoli, cabbage, and more digests down into DIM, a compound with brighter benefits than the name implies, such as inducing cell death in breast, prostate, and colon cancer.

In a report in PLOS One, Hiroshima University researchers found that DIM, or 3,3’-Diindolylmethane, also triggers controlled whole-cell death and recycling of cellular components in fission yeast. Whether the DIM-induced damage mechanism is conserved in humans remains to be seen, but HU Associate Professor Masaru Ueno explained that unicellular fission yeast allows for easier examination of the molecular machinery that mimics behavior in more complex organisms.

Part of the cell’s process of repair is called autophagy, or “self-eating.” If repair is no longer an option, cells will rupture in a programmed death process called apoptosis. Many cytotoxic anticancer drugs work by inducing apoptosis, so being able to control the process can help preserve and improve human health.

It may seem counter-intuitive that an apoptosis-inducing compound can increase the lifespan of an organism, but DIM appears to prompt such behavior only in exponentially dividing cells — like cancer.

The understanding of apoptosis and autophagy mechanism by DIM in fission yeast may be helpful for human cancer and longevity research. Find the original article and Hiroshima University research news here: https://www.hiroshima-u.ac.jp/en/news/68805

A better black hole laser may prove a circuitous ‘Theory of Everything’

Posted on by Hiroshima University

The fundamental forces of physics govern the matter comprising the Universe, yet exactly how these forces work together is still not fully understood. The existence of Hawking radiation — the particle emission from near black holes — indicates that general relativity and quantum mechanics must cooperate. But directly observing Hawking radiation from a black hole is nearly impossible. So how can researchers study it to better understand how the forces integrate into a “Theory of Everything”?

According to Hiroshima University doctoral student Haruna Katayama, since researchers cannot go to the Hawking radiation, it must be brought to them. She proposed a quantum circuit that acts as a black hole laser using an analogue black hole and a white hole as a resonator to amplify weak Hawking radiation. The proposal was published in Scientific Reports.

“In the proposed circuit, the metamaterial element makes it possible for Hawking radiation to travel back and forth between horizons, and the Josephson effect plays an important role in amplifying Hawking radiation through the mode conversion at the horizons, mimicking the behavior between the black and white holes,” Katayama said.

The proposed laser also provides a future light source for quantum information technology.

Is mimamoru, Japan’s hands-off approach in disciplining schoolchildren, worth a try?

Posted on by Hiroshima University

A study examining Japanese schools’ hands-off approach when children fight showed it could create opportunities for autonomy and encourage ownership of solutions, suggesting a new strategy in handling kids squabbles in other countries.

Called mimamoru, the pedagogical strategy is a portmanteau of the Japanese words mi, meaning watch, and mamoru, meaning protect. It’s generally understood as “teaching by watching” — where adults intentionally let kids handle disagreements by themselves to promote learning through voluntary exploration and actions.

“This study aims to understand the reason why Japanese early childhood educators tend not to intervene, and how and in what contexts they do,” said study author and Hiroshima University Associate Professor Fuminori Nakatsubo.

A total of 34 Japanese and 12 US early childhood educators participated in focus groups that used modified video-cued multi-vocal ethnography methods to scrutinize the non-intervention strategy. Their findings are published in the Early Childhood Education Journal.

The study noted that allowing children to experience feelings of physical pain or guilt can be a teachable moment that physical fights do not solve any problem.

The researchers, however, clarified that “watching” doesn’t mean that adults ignore children’s safety. Japanese educators intervene when the risk of physical harm caused by fighting outweighs the benefit for children to learn. This story was first published on the Hiroshima University website.

Invasive weed may help treat some human diseases, researchers find

Posted on by Hiroshima University

Native to the southeastern United States, a weedy grass has spread northward to Canada and also made its way to Australia and Japan. Andropogon virginicus grows densely packed and up to seven feet tall, disrupting growth patterns of other plants and competing for resources. When burned, it grows back stronger. There is no way to effectively remove the weed once it has invaded. But there might be a way to use it to human advantage.

An international team of researchers has found that A. virginicus extracts appear to be effective against several human diseases, including diabetes and cancer. The results were published in a special issue of Plants last December.

“A. virginicus is an invasive weed that seriously threatens agricultural production and economics worldwide,” said paper author Tran Dang Xuan, associate professor at Hiroshima University’s Graduate School of Advanced Science and Engineering. “However, no solution efficiently utilizing and tackling this plant has been found yet.”

Researchers found high levels of flavonoids in the samples they extracted from the weed. These plant chemicals have significant antioxidant and anti-inflammatory properties, according to Xuan. When tested against a variety of cell lines, the extracted plant chemicals bonded to free radicals, preventing damage to the cells. At skin level, this helps prevent age spots by inhibiting a protein called tyrosinase. Among other, deeper healthful actions, this bonding also helps prevent knock-on cellular actions that can lead to type 2 diabetes.

The team also specifically applied the plant extracts to a line of chronic myelogenous leukemia, a rare blood cancer. The extract appeared to kill off the cancer cells.

Xuan said the researchers plan to establish a comprehensive process to isolate and purify the compounds responsible for known biological properties, as well as work to identify new uses.

This story was first published on the Hiroshima University website.