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Comment by Dr. Krishna Kumari Challa on December 30, 2025 at 8:21am

How to make clear ice at home

The simplest way to have a go at directional freezing at home is to use an insulated container—you can use a really small cooler (that is, an "esky"), an insulated mug or even a commercially available insulated ice cube tray designed for making clear ice at home.

Fill the insulated container with water and place it in the freezer, then check on it periodically.

Once all the impurities and air bubbles are concentrated in a single cloudy area at the bottom, you can either pour away this water before it's fully frozen through, or let the block freeze solid and then cut off the cloudy portion with a large serrated knife, then cut the ice into cubes for your drinks.

If using a commercial clear ice tray, it will likely come with instructions on how to get rid of the cloudy portion so you can enjoy the sparkling clear ice.

How do I make clear ice at home? A food scientist shares easy tips

Author: Paulomi (Polly) Burey

Professor in Food Science, University of Southern Queensland

Part 3

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Comment by Dr. Krishna Kumari Challa on December 30, 2025 at 8:20am

Myths about clear ice that don't work

You might think that to get clear ice, you simply need to start out with really clean water. However, a recent study found this isn't the case.

Using boiling water: Starting out with boiling water does mean the water will have less dissolved gases in it, but boiling doesn't remove all impurities. It also doesn't control the freezing process, so the ice will still become cloudy.

Using distilled water: While distilling water removes more impurities than boiling, distilled water still freezes from the outside in, concentrating any remaining impurities or air bubbles in the center, again resulting in cloudy ice.

Using filtered or tap water: Filtering the water or using tap water also doesn't stop the impurities from concentrating during the conventional freezing process.

What actually works

As it turns out, it's not the water quality that guarantees clear ice. It's all about how you freeze it. The main technique for successfully making clear ice is called "directional freezing."

Directional freezing is simply the process of forcing water to freeze in a single direction instead of from all sides at once, like it does in a regular ice cube tray.

This way, the impurities and air will be forced to the opposite side from where the freezing starts, leaving the ice clear except for a small cloudy section.

In practice, this means insulating the sides of the ice container so that the water freezes in one direction, typically from the top down. This is because heat transfer and phase transition from liquid to solid happens faster through the exposed top than the insulated sides.

Part 2

Comment by Dr. Krishna Kumari Challa on December 30, 2025 at 8:19am

How do I make clear ice at home? A food scientist shares easy tips

Clear ice forms when water freezes in a single direction, pushing air and impurities to one end, unlike typical home freezing that traps them throughout the cube and causes cloudiness. Using an insulated container to promote directional freezing produces clear ice, while water quality or boiling alone does not prevent cloudiness. Clear ice is denser, melts slower, and resists imparting flavors.

Clear ice is actually made from regular water—what's different is the freezing process.

With a little help from science, you can make clear ice at home, and it's not even that tricky. However, there are quite a few hacks on the internet that won't work. Let's dive into the physics and chemistry involved.

Why ice goes cloudy

Homemade ice is often cloudy because it has a myriad of tiny bubbles and other impurities. In a typical ice cube tray, as freezing begins and ice starts to form inward from all directions, it traps whatever is floating in the water: mostly air bubbles, dissolved minerals and gases.

These get pushed toward the center of the ice as freezing progresses and end up caught in the middle of the cube with nowhere else to go.

That's why when making ice the usual way—just pouring water into a vessel and putting in the freezer—it will always end up looking somewhat cloudy. Light scatters as it hits the finished ice cube, colliding with the concentrated core of trapped gases and minerals. This creates the cloudy appearance.

The point of clear ice

As well as looking nice, clear ice is denser and melts slower because it doesn't have those bubbles and impurities. This also means that it dilutes drinks more slowly than regular, cloudy ice.

Because it doesn't have impurities, the clear ice should also be free from any inadvertent flavors that could contaminate your drink.

Additionally, because it's less likely to crumble, clear ice can be easily cut and formed into different shapes to further dress up your cocktail.

If you've tried looking up how to make clear ice before, you've likely seen several suggestions. These include using distilled, boiled or filtered water, and a process called directional freezing. Here's the science on what works and what doesn't.

Part 1

Comment by Dr. Krishna Kumari Challa on December 30, 2025 at 8:12am

they gathered new valuable observations that could explain in greater detail known differences between the brain functions of humans and other primates. Notably, the researchers also identified transcription factors that modulate the development of the human brain but not of macaques, while also pinpointing types of cells in human tissues that are known to be affected in the brains of patients with specific disorders.

Jiyao Zhang et al, Single-cell spatiotemporal transcriptomic and chromatin accessibility profiling in developing postnatal human and macaque prefrontal cortex, Nature Neuroscience (2025). DOI: 10.1038/s41593-025-02150-7

Part 2

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"Our discoveries shed light on human-specific regulatory programs extending postnatal cortical maturation through coordinated neuronal and glial development, with implications for cognition and neurodevelopmental disorders," wrote the team.

Comment by Dr. Krishna Kumari Challa on December 30, 2025 at 8:09am

Why the human brain matures slower than its primate relatives

The human brain is a fascinating and complex organ that supports numerous sophisticated behaviors and abilities that are observed in no other animal species. For centuries, scientists have been trying to understand what is so unique about the human brain and how it develops over the human lifespan.

Researchers have recently set out to study both the human and macaque brain, comparing their development over time using various genetic and molecular analysis tools. Their paper, published in Nature Neuroscience, highlights some key differences between the two species, with the human pre-frontal cortex (PFC) developing slower than the macaque PFC.

The researchers collected several samples of brain tissue that was surgically removed from the PFC of macaques and humans at different stages after birth. The human subjects were children with epilepsy who were undergoing surgical procedures as part of their treatment plan.

The researchers analyzed the expression of genes in single cells taken from the tissues they collected, as well as chromatin accessibility (i.e., how open DNA is within individual cells). They also mapped the expression of genes across the entire brain tissues, using a technique known as spatial transcriptomics, and looked at the types of cells that were present.

"Integrative analyses outlined species-specific dynamic trajectories of different cell types, highlighting key windows and gene regulatory networks for processes such as synaptogenesis, synaptic pruning and gliogenesis," wrote the authors in their paper.

The researchers' analyses revealed that the human PFC takes longer to develop than that of macaques. They also observed that glial progenitors (i.e., stem-like cells that later divide and develop into specific types of glial cells) proliferate more in humans.
"We identified regulatory correlates of the prolonged development of human PFC relative to macaques," wrote the researchers. "Glial progenitors showed higher proliferation capability in humans compared to macaques, associated with distinct gene expression profiles. Furthermore, we uncovered cell types and lineages most susceptible to neurodevelopmental and neuropsychiatric disorders, focusing on transcription factors with human-specific expression features."

Part 1

Comment by Dr. Krishna Kumari Challa on December 29, 2025 at 10:59am

Get this right: 

Over 50% of Heart Attacks in Younger Women Aren't From Clogged Arteries

Traditionally, most heart attacks have been blamed on clogged arteries causing atherothrombosis – where blood clots block flow to the heart.
But research suggests we may be underestimating the role of other causes, particularly in younger adults.

Scientists from the Mayo Clinic in the US analyzed 1,474 heart attack events in people aged 65 or younger, recorded between 2003 and 2018 in Olmsted County, Minnesota. By carefully reviewing medical records and imaging, they identified a primary cause behind each case.

Strikingly, more than half of heart attacks in women were found to have non-atherothrombotic causes.

Atherothrombosis accounted for 75 percent of heart attacks in men, which wasn't surprising. But in women, it was behind 47 percent – less than half. That has major implications for the prevention and treatment of heart attacks.

This research shines a spotlight on heart attack causes that have historically been under-recognized, particularly in women. In women, 34 percent of all heart attack events were attributed to supply/demand mismatch secondary myocardial infarctions (SSDMs) – defined as an imbalance of oxygen supply and demand caused by other stressors on the body, such as anemia or an infection.

Among the other factors significantly contributing to heart attacks were spontaneous coronary artery dissections (SCADs), where tears in artery walls collect blood, and embolisms (blood clots traveling from other areas of the body).

Causes of Myocardial Infarction in Younger Patients: Troponin-Eleva...

Comment by Dr. Krishna Kumari Challa on December 26, 2025 at 9:31am

Why do reindeer eyes change colour?

Comment by Dr. Krishna Kumari Challa on December 25, 2025 at 10:20am

For consumers, reducing fruit drop means better access to fresh, affordable produce. For growers, it's about staying viable in an increasingly unpredictable climate. And for policymakers, it's about preparing the horticultural industry for the challenges ahead.

Importantly, fruit drop isn't unique to mangoes. Apples, citrus, and avocados also suffer losses due to hormonal imbalances triggered by environmental stress.

Better understanding the molecular mechanisms controlling fruit drop in mango, could benefit a wide range of fruit crops globally as the climate changes.

This article is republished from THE CONVERSATION under a Creative Commons license. Read the original article.

Part 2

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Comment by Dr. Krishna Kumari Challa on December 25, 2025 at 10:14am

Why mangoes fall before they're ripe—and how science is helping them hang on

 Why your mango tree drops fruit before it's ripe? Each season, mango growers across the world watch helplessly as millions of mangoes fall to the ground too early.

These mangoes never ripen properly, never reach consumers, and represent a major loss—both economically and environmentally.
Premature fruit drop is a major contributor to low mango yields, with as little as 0.1% of fruits reaching maturity. This costs growers millions and wastes valuable resources.
As climate stress intensifies, understanding why fruit is lost before harvest has global significance. It affects everything from food security to farm profitability.

Its sensitivity to environmental stress makes it vulnerable in a less predictable and more extreme climate. Drought, heat waves, and even leaf loss can influence a natural process that leads to fruit drop.

Just like humans, plants rely on hormones to keep things growing and functioning smoothly.

These chemical messengers help regulate everything from flowering to fruit development.

But when plants experience stress, hormone levels shift. The plant starts reallocating resources to survive. Dropping fruit is often one of the first sacrifices.

One key resource that plants reallocate is carbohydrates. Developing fruit requires a steady supply of sugars, but under stress—such as leaf damage or water scarcity—the tree may struggle to produce or transport enough.

This can trigger fruit drop, as the plant prioritizes survival over reproduction.

Stress not only disrupts carbohydrate supply but also interferes with the hormonal balance in mango trees. This triggers what we call a molecular "quit signal": a message from the plant to let go of its fruit.

This signal is a part of a complex network of gene activity and hormonal cues that help the tree decide when to shed fruit.

Researchers are studying the molecular pathways behind this signal by analyzing gene signals from mango pedicel tissue—the stem that connects the fruit to the tree.

This tissue acts like a control center, managing the flow of nutrients and signals between the tree and the developing fruit. It's where the tree and fruit stay in touch, especially during stress.

By analyzing which genes are turned on or off, we can pinpoint the molecular signals involved in fruit drop, particularly those related to hormones.

This helps us move from just observing fruit drop to developing tools to control it.

One promising solution is the use of plant growth regulators, which are synthetic versions of plant hormones.

These can be applied to mango trees to help stabilize hormone levels during stressful conditions.

It's a bit like giving the tree a hormonal pep talk, encouraging it to hold onto fruit even when times are tough.

Applying plant growth regulators during flowering, before fruit has fully emerged, was more effective than applying them later in the season.

This early intervention helped reinforce the hormonal signals that support fruit retention. Initial trials have increased tree yield by up to 17%.

Even small-scale growers might one day use targeted treatments to help their trees hold on to fruit longer.

Part 1

Comment by Dr. Krishna Kumari Challa on December 24, 2025 at 9:53am

Fathers' microplastics exposure tied to their children's metabolic problems

Paternal exposure to microplastics in mice leads to metabolic dysfunction in offspring, with female progeny showing increased susceptibility to diabetes and altered gene expression linked to inflammation. These effects are associated with changes in sperm small noncoding RNAs, indicating a mechanism for transgenerational impact of environmental pollutants.

A new study has shown for the first time that a father's exposure to microplastics (MPs) can trigger metabolic dysfunctions in his offspring. The research, conducted using mouse models, highlights a previously unknown pathway through which environmental pollutants impact the health of future generations.

While MPs have already been detected in human reproductive systems, the study, published in the Journal of the Endocrine Society, is the first to bridge the gap between paternal exposure to MPs and the long-term health of the next generation (the "F1 offspring").

MPs are tiny plastic particles (less than 5 millimeters) resulting from the breakdown of consumer products and industrial waste. Metabolic disorders refer to a cluster of conditions—including increased blood pressure, high blood sugar, and excess body fat—that increase the risk of heart disease and diabetes.

Key findings and sex-specific effects The research team found that female offspring of male mice exposed to MPs were significantly more susceptible to metabolic disorders than offspring of unexposed fathers, despite all offspring being fed the same high-fat diet.

"The exact reasons for this sex-specific effect are still unclear", say the researchers. They observed upregulation of pro-inflammatory and pro-diabetic genes in their livers—genes previously linked to diabetes. These changes were not seen in male offspring.
The research team found that while male offspring did not develop diabetes, they showed a slight yet significant decrease in fat mass. Female offspring showed decreased muscle mass alongside increased diabetes.

Seung Hyun Park et al, Paternal microplastic exposure alters sperm small non-coding RNAs and affects offspring metabolic health in mice, Journal of the Endocrine Society (2025). DOI: 10.1210/jendso/bvaf214

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