Recent comments in /f/science

-TheOnlyOutlier- t1_jd7po0f wrote

Reply to comment by panmex in A crucial building block of life exists on the asteroid Ryugu. Uracil, a component of RNA, was found in a sample collected by Japan’s Hayabusa2 spacecraft. by Science_News

Contamination wouldn't occur due to the spacecraft, but due to handling in the lab. While I'm not an expert on organic chemistry, I think it's pretty unlikely that organic contamination would ONLY include uracil. Scientists spend a lot of time making sure their data is significant. Additionally, this isn't the only research group with Ryugu samples that has found complex organics, though I think these might be the most complex found so far.

Source: I work with Ryugu samples. Take my opinion with a grain of salt as I'm still in grad school.

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Wagamaga OP t1_jd77oo0 wrote

Reply to Air pollutants have been confirmed to increase the risk of Alzheimer's dementia. Air pollutants enter the lungs through the respiratory tract and cause inflammation, which causes various diseases throughout the body, especially the inflammation of nerves when it reaches the brain. by Wagamaga

Professors Cho Jae-rim and Kim Chang-soo of Yonsei University College of Medicine’s Prevention Medicine Class and Professor Roh Young of the Neurology Department at Gachon University Gil Medical Center conducted the study.

Air pollutants enter the lungs through the respiratory tract and cause inflammation, which causes various diseases throughout the body, especially the inflammation of nerves when it reaches the brain. The research team confirmed through previous studies that air pollutants affect the atrophy of the cerebral cortex. Still, no evidence exists that this phenomenon led to cognitive decline and Alzheimer's.

Cortical changes in the cerebral cortex are closely related to brain diseases, including Alzheimer's. The average cerebral cortex thickness in healthy ordinary people is 2.5 millimeters, but that of patients with Alzheimer's was thinner, with 2.2mm.

The researchers studied the effects air pollution has on brain health using three primary air-polluting materials – ultrafine dust (PM2.5), fine dust (PM10), and nitrous oxide (NO2) – as indicators in 640 healthy adults 50 and older with no brain diseases in Seoul, Incheon, Wonju and Pyeongchang for 32 months from August 2014.

The result showed that the thickness of the cerebral cortex decreased as the concentration of air pollutants increased. For instance, when the concentration of fine dust and ultrafine dust increases by 10μg/, and nitrogen dioxide increases by 10ppb, the thickness of the cerebral cortex decreases by 0.04mm, 0.03mm, and 0.05mm.

https://www.koreabiomed.com/news/articleView.html?idxno=20668

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AutoModerator t1_jd77mgy wrote

Reply to Air pollutants have been confirmed to increase the risk of Alzheimer's dementia. Air pollutants enter the lungs through the respiratory tract and cause inflammation, which causes various diseases throughout the body, especially the inflammation of nerves when it reaches the brain. by Wagamaga

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marketrent OP t1_jd7422n wrote

Reply to Some trilobites had third, fourth and fifth eyes located in the middle of their forehead — with lenses not unlike human eyes by marketrent

Excerpt from the linked summary:^1

>Trilobites, prehistoric sea creatures, had so-called median eyes, single eyes on their foreheads, in addition to their compound eyes, research conducted by Dr Brigitte Schoenemann at the University of Cologne’s Institute of Zoology and Professor Dr Euan Clarkson at the University of Edinburgh has now found out.

>Such single eyes are found in all arthropods and also in many relatives of the extinct trilobites. They are usually small cup eyes (ocelli), sometimes even equipped with lenses, and not unlike human eyes.

>Schoenemann and Clarkson examined a specimen of the trilobite Aulacopleura koninckii in which part of the head had been scraped off.

>They found three almost identically shaped dark, inconspicuous and tiny oval spots of the same size at the front of the head. These three structures are parallel to each other and fan out slightly on the underside.

>All three spots are characterized by a smooth, clear outline and a uniform, dark brownish colour.

> 

>In the trilobite Cyclopyge sibilla, which lived in the free ocean, the researchers also found three cup-shaped median eyes on the so-called glabella, the region in the middle of the forehead between the large compound eyes, which even apparently had a lens not unsimilar to human eyes, and were thus clearly more differentiated and probably much more efficient than those of the bottom-dwelling trilobite Aulacopleura.

>In their article, the researchers also consider why the median eyes of trilobites have escaped detection until now: “These eyes are present in trilobites at the larval stage, but lie beneath what is probably a thin, transparent carapace (cuticle), which becomes opaque during fossilisation.

>Both explain why they have remained undiscovered until now,” she added. Thus, the researchers have solved the mystery of missing middle eyes in trilobites.

^1 New eyes discovered in trilobites, 17 Mar. 2023, https://portal.uni-koeln.de/en/universitaet/aktuell/press-releases/single-news/new-eyes-discovered-in-trilobites

^2 Schoenemann, B., Clarkson, E.N.K. The median eyes of trilobites. Scientific Reports 13, 3917 (2023). https://doi.org/10.1038/s41598-023-31089-7

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