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Simulations suggest a breakthrough in understanding how turbulence develops

A new study revisits a century-old question about how turbulence starts. The findings could potentially influence not only aircraft engineering but even the design of mechanical heart valves, and treatment of heart disease. The study is published in Scientific Reports.

Computer simulations at Stockholm’s KTH Royal Institute of Technology indicate that very small vortices may create increasingly larger swirls of flow—the opposite of the traditional view of how energy is transferred in turbulence.

Often seen in nature, from whirlpools to the shape of galaxies, vortices are one of the main flow structures that drive turbulence. The dominant idea over the last 100 years is that large swirling motions in a fluid break apart into smaller and smaller swirls, passing energy down the chain until it finally disappears—a process known as the forward cascade.

The Mass-Budget Discrepancy of 3I/ATLAS

Planetary systems — which serve as the natural birth sites of interstellar objects — originate from debris disks that contain at least ten times less mass than the host star. In addition, one expects a mass spectrum of ejected interstellar objects to contain at least ten times more mass in objects with masses that are orders of magnitude different from that of 3I/ATLAS. When these additional factors are included, we find that low-metallicity stars miss the required mass budget by at least 3 orders of magnitude. They cannot account for the interstellar population of 3I/ATLAS-like objects unless they are capable of ejecting to interstellar space more than a thousand times the heavy-element content of their planetary disks.

In conclusion, either the inferred radius or number density of the population of 3I/ATLAS-like objects are overestimated or their association with metal-poor stars is incorrect.

Breakthrough to Strengthen Bones Could Reverse Osteoporosis

Research points to a key bone-strengthening mechanism at work in the body, which could be targeted to treat the bone-weakening disease, osteoporosis.

Led by scientists from the University of Leipzig in Germany and Shandong University in China, the 2025 study identified the cell receptor GPR133 (also known as ADGRD1) as being crucial to bone density, via bone-building cells called osteoblasts.

Variations in the GPR133 gene had previously been linked to bone density, leading researchers to turn their attention to the protein it encoded.

Dendrite-Targeting Inhibitory Interneurons Form Biased Circuits with Deep and Superficial Pyramidal Cells in Hippocampal CA1

JNeurosci: Johantges et al. used mice to study excitatory and inhibitory synaptic connections in the CA1 region, creating a circuit map with cell-type resolution that will guide future research on how the hippocampus supports learning and memory.

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In the CA1 hippocampus, pyramidal cells (PCs) can be classified as deep or superficial based on their radial position within the stratum pyramidale. Deep and superficial PCs form biased circuits with perisomatic-targeting PV+ basket cells, but it is unknown if such cell-type–specific circuit motifs extend to dendrite-targeting interneurons. Using male and female mice, we investigated synaptic connectivity and physiology in brain slices from four transgenic lines thought to capture distinct subsets of interneurons: SST-IRES-Cre, Nkx2.1-Cre, Chrna2-Cre, and Htr3a-GFP. First, we found that oriens-lacunosum moleculare (OLM) cells captured by the Chrna2-Cre line are a subset of Htr3a-GFP+ cells in the hippocampus. This novel finding is consistent with previous work showing Nkx2.1-Cre OLM cells are distinct from both Chrna2-Cre and Htr3a-GFP+ OLM cells.

Clinical Reasoning: A 49-Year-Old Man With Meningoencephalitis and Persistent Altered Mental Status

Cannabis use is common among those with mental health conditions, and many people report using cannabis to manage mental health symptoms.

It is important for clinicians to understand the lack of clear benefits of cannabis for mental health conditions and the potential for substantial adverse effects.

📌 This Review summarizes the current evidence on the effects of cannabis on commonly encountered mental health conditions and provides clinicians with basic information about cannabis pharmacology and biology.

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