Juan Garcia-Ruiz

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Why do our eyes feel dry in the cold? ❄️👁️

Cold air holds little moisture, so the tear film evaporates faster. Corneal nerves sense the temperature drop and trigger reflex tears, but these lack the oily layer from Meibomian glands, leaving the surface exposed and dryness persists.

#SciComm 🧪

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Why do humans need better cooling than furry mammals? 🏃‍♂️☀️

We evolved to run and stay active for hours in hot, open environments. Losing most fur and sweating a lot lets us cool down quickly, much better than breathing fast or resting in the shade like most mammals.

#SciComm 🧪

Why do most mammals have thick fur 🐒, while humans are nearly hairless except in select spots🧔?

Our sweating-based cooling demanded less fur, but we kept dense hair in areas that guard sensitive skin and boost chemical communication.

#SciComm 🧪

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Is your brain in your hands? 🇪🇸 🇬🇧 | There is a great cliché that says that we are all the same. And another one that says that each person is unique. But what does biology say about this?

www.neuronhub.org/Is-your-brai... Fascinating long interview with Silvia Bunge on higher brain functions by Juan Garcia-Ruiz @juangarciaruiz.bsky.social.

"What you do repeatedly is going to influence your outcomes. You shouldn’t be afraid to try new things."

🌍 Why rely on hard-to-get fish fats? Early humans lived near coasts rich in algae-fed food, and evolution left production to plants and algae. Today’s challenge is restoring that ancestral balance in modern diets.

🐟 EPA and DHA keep membranes flexible and control inflammation, supporting neurons and blood vessels. We need 250–500 mg/day (≈2 servings oily fish weekly or algae oil). Plant omega-3 (ALA) converts poorly, so 1–2 g/day from chia or walnuts helps but isn’t enough alone.

🧪 Why are omega-3 and omega-6 essential?

They’re fats our body can’t make but needs for brain, heart, and cells. Omega-3 has its first double bond at the 3rd carbon, omega-6 at the 6th. Plants give short omega-3 (ALA), fish and algae give long, active ones (EPA, DHA).

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Like father, like worm 🇪🇸 🇬🇧 | Today, modern biologists, especially those studying epigenetics, are finding that the environment can influence heredity.

Can acquired traits be inherited? I discussed this fascinating question with @odedrechavi.bsky.social, a brilliant researcher and the mind behind some legendary Academia memes. Enjoy the reading:

🧪🔗 www.neuronhub.org/Like-father-...

Meet CALF-20, a super-sponge with vast internal caverns that store gases like CO₂, trap toxins, and carry therapeutic compounds. One gram has an internal area of 7839 m²!

Its discovery won Susumu Kitagawa, Richard Robson & Omar Yaghi the 2025 Nobel Prize in Chemistry.

🔗🧪 doi.org/10.1038/d415...

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“SB: Your brain is in your hands. What you do repeatedly is going to influence your outcomes. You shouldn’t be afraid to try new things. Your brain is plastic, and you can do things you didn’t think you could do. It’s important to maintain your cognitive ability with new challenges […]”

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Is your brain in your hands? 🇪🇸 🇬🇧 | There is a great cliché that says that we are all the same. And another one that says that each person is unique. But what does biology say about this?

Is your brain in your hands? 🧠

I interviewed Silvia Bunge, a renowned researcher at UC Berkeley, about how cognition can be shaped by individual differences and socioeconomic status.

🔗🧪 www.neuronhub.org/Is-your-brai...

I hope you enjoy the read!

This process is called nucleation, the start of a phase change like liquid turning to vapor. It lowers the energy needed to form bubbles at surfaces. Nucleation happens all around us, from boiling water to dew forming on leaves or frost on windows, making phase changes faster and easier.

3/3 🧪

The reason energy is lower is that forming a bubble in open water means creating a full liquid-gas surface (hard with surface tension). In a cavity, part of the bubble touches the solid, so less new liquid-gas surface forms. This means surface tension acts less and bubble formation is easier.

2/3 🧪

When you boil water, bubbles first form at tiny imperfections on the pot’s surface. These spots trap air pockets that lower the energy needed for vapor to form. This triggers boiling, helping bubbles appear fast instead of waiting for rare, random events inside pure water.

1/3 🧪

How are these electric fields created? ⚡🧪

Muscle cells have a resting voltage from ion differences inside/outside. When nerves fire, ion channels open causing action potentials. Many fibers’ action potentials sum, creating tiny electric fields muscles emit into water (detected by electroreceptors).

The platypus’s bill has 40000 electroreceptors and 60000 mechanoreceptors. It senses tiny electric fields and water movements from prey. Sweeping its bill side to side, the platypus finds hidden food underwater, hunting well even in the dark or cloudy water. ⚡🌊

#SciComm 🧪

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Why panda’s thumbs are not thumbs? 🐼👍

It’s actually a wrist bone, not a true digit: a nice example of evolutionary tinkering (nature repurposing parts for new jobs). It evolved for gripping bamboo, and both giant and red pandas did this independently (convergent evolution).

#SciComm 🧪

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