Comment

Comment by Dr. Krishna Kumari Challa yesterday

The first is habitat fragmentation. Borders can cut animals off from their natural ranges, and that is especially dangerous for animals with a very small travel radius, such as reptiles and some birds. Imagine a lizard who only travels up to a quarter mile from home. Then, imagine a fence going up in the middle of that lizard's already tiny range, restricting its stomping grounds—and potential food supply—even more. And don't forget that border infrastructure like bright lights, non-native landscaping, roads and increased staff will further hamper that lizard's ability to hunt, forage and even reproduce.
The second involves less genetic variation. International borders can disrupt animals' ability to interact and breed with each other. That means that over time, they become less genetically diverse, leading to a decrease in immunity to certain diseases. With time, they may even become inbred and unable to reproduce.
And, finally, there are fewer safety nets. Some endangered species are legally protected in one country but illegally poached in another. Without international cooperation on wildlife conservation, lax hunting laws and enforcement will continue to hurt animals who exist on both sides of a border fence.
There are a few benefits too:
Even in places where animals are threatened by poaching on one side of a border fence, they're shielded from it on the other—guaranteeing they won't go completely extinct. Borders can also shield animals from disease.
Part 2

Comment by Dr. Krishna Kumari Challa yesterday

Border fences are bad for wildlife

International border barriers everywhere are harming wildlife by bisecting their habitats, disrupting their hunting and collecting patterns and preventing them from commingling. In some cases, the borders are causing so much harm that they could cause certain species to go extinct.

That's according to a new study published in the journal Biological Conservation.

The literature review, which analyzed 42 studies on wildlife and borders by scientists across the globe, was part of a special issue on addressing land degradation.

With border barriers, the habitat that animals once moved freely across is divided, fragmenting populations, reducing availability to water, lowering gene flow and even killing animals that try to cross.

Animals don't recognize political boundaries—they are tied to the resources that they need to survive. It's hard seeing animals come up against a new barrier—a huge wall or fence—that stops their ability to get a drink of water or find seasonal foods, especially in desert environments.

The problem has become worse due to a dramatic increase in border barriers in the 21st century. According to a report from the Migration Policy Institute there were just two dozen border walls across the world in 2000; two decades later, that number has tripled. 

The researchers found   three main ways in which physical borders were harming wildlife.

Part 1

Comment by Dr. Krishna Kumari Challa yesterday

Frustration can lead to failure for search and rescue dogs

Search and rescue dogs are heroes in fur coats, using their incredible sense of smell to find lost hikers, disaster victims, and missing people. But a new study suggests that these life-saving dogs may face an unexpected obstacle: frustration.

Researchers found that frustration significantly impacts search and rescue dogs' ability to perform search tasks effectively. In a study published in Frontiers in Veterinary Science, they reported that when the dogs experience frustration—such as blocked access to a reward or an unfulfilled expectation—they are slower to complete their searches and are more prone to errors.

Search and rescue dogs are trained to work in high-pressure environments, from collapsed buildings to dense forests. While they are known for their endurance and focus, certain factors can affect their work.

To test what factors affect their work, researchers  enlisted a dozen dogs and their handlers to participate in three activities. The dogs wore special collars to track heart rate and heart rate variability—key indicators of exertion and stress. Researchers also recorded the dogs' search accuracy and speed in locating a target odor and surveyed the dogs' handlers on their behaviors.

In the first activity, the dogs rested under normal, quiet conditions for 10 minutes.

In the second "frustration activity," handlers teased the dogs with an unattainable toy, withheld their attention, and then led the dog to complete a search.

In the third exercise, the handlers led the dogs through a moderate workout before completing the search.
The results showed:
After experiencing frustration, search dogs took significantly longer to indicate they found their search targets.
The dogs made more errors after the frustration activity.
Frustration increased the dogs' heart rate and decreased their heart rate variability, indicating a higher level of stress and reduced ability to recover.
Physical exertion caused increased heart rate but did not change heart rate variability, indicating no significant stress response to exercise.

The researchers say the information is valuable for search and rescue (SAR) handlers, many of whom rely on longstanding training methods that use frustration as a tool to build dogs' perseverance. We often think of frustration as a motivator, but these  findings show that it can backfire, slowing dogs down and increasing errors. And that's a serious concern.

It's our responsibility to make their work as stress-free and enjoyable as possible, they conclude.

Sally Dickinson et al, Frustration and its impact on search and rescue canines, Frontiers in Veterinary Science (2025). DOI: 10.3389/fvets.2025.1546412

Comment by Dr. Krishna Kumari Challa yesterday

Developing an Ecotoxicological Classification for Frequently Used Drugs in Primary Care

A classification of drugs based on their environmental impact

Scientists at the University of Lausanne (UNIL) and University center Unisanté classified 35 commonly used drugs based on their impact on the aquatic biodiversity.

The aim of this research is to provide medical staff with a tool for considering the environmental risks associated with certain common drugs when prescribing them. The proposed list is subject to change when new data becomes available, their rarity being a limiting factor for classification.

Every day all around the world, thousands of drugs are consumed, whether to relieve pain, regulate blood pressure or treat infections. But what happens after ingesting these products? Evacuated via urine, many substances end up in wastewater. They are only partially eliminated by these systems, and end up in lakes, rivers and streams, posing a risk to aquatic ecosystems. This risk is now recognized, but it is difficult for doctors to know how to integrate it into their practice.

At the University of Lausanne (UNIL), scientists from the Faculty of Biology and Medicine (FBM) and the Faculty of Geosciences and Environment (FGSE) have carried out a classification of widely-used drugs according to their ecotoxicity, i.e. their danger to the aquatic ecosystem. Published in the International Journal of Environmental Research and Public Health, the study reveals that drugs commonly prescribed in general medicine—to combat inflammation or infection, for example—have significant consequences for the health of fish, algae and bacteria essential to aquatic biodiversity.

The researchers classified 35 drugs commonly consumed into categories ranging from low to high toxicity for aquatic ecosystems. To do this, they cross-referenced three pieces of information: the 50 most widely sold drugs  (by weight), those for which ecotoxicity thresholds exist, and the concentration of those found in the rivers  (in the form of active ingredients).

Among the most problematic drugs are common painkillers and anti-inflammatories such as diclofenac, which is toxic to fish liver and can lead to fish death. There are also antibiotics such as ciprofloxacin, which can eliminate bacteria useful to the ecosystem's balance, and encourage the emergence of antibiotic-resistant bacteria. Mefenamic acid and paracetamol, on the other hand, are in the category with the lowest environmental risks.

This classification is far from complete, because of the lack of data. It does, however, give some initial indications for practitioners, say the eco-toxicologists.

 Developing an Ecotoxicological Classification for Frequently Used Drugs in Primary Care, International Journal of Environmental Research and Public Health (2025). doi.org/10.3390/ijerph22020290

Comment by Dr. Krishna Kumari Challa yesterday

Air pollution and traffic noise increase the risk of stroke through combination effect

New research shows that air pollution and traffic noise together may pose a greater risk for stroke than either factor alone. The researchers found that even at low levels—below the EU's air quality standards and around WHO noise recommendation levels—the risk of stroke increased significantly.

The study, published in Environment International, analyzed data from 136,897 adults in Sweden, Denmark, and Finland. The results show that a 5 µg/m³ increase in air pollution (PM_2.5) raises the risk of stroke by 9%, while an 11 dB increase in traffic noise increases the risk by 6%.

When both factors are combined, the risk may be even higher. For example, in quieter areas (40 dB), an increase in PM_2.5 was linked to a 6% rise in stroke risk, but in noisier areas (80 dB), the same increase in PM_2.5 raised the risk by 11%, though this result was not statistically significant.

The fact that we see clear associations even at relatively low levels indicates that current exposure limits may not be sufficient to protect public health. Stronger regulations are needed to reduce exposure and lower the risk of stroke and other diseases, say the researchers.

 Huyen Nguyen Thi Khanh et al, Exploring the interaction between ambient air pollution and road traffic noise on stroke incidence in ten Nordic cohorts, Environment International (2025). DOI: 10.1016/j.envint.2025.109403

Comment by Dr. Krishna Kumari Challa yesterday

Scientists merge two 'impossible' materials into new artificial structure

An international team of researchers has merged two lab-synthesized materials into a synthetic quantum structure once thought impossible to exist and produced an exotic structure expected to provide insights that could lead to new materials at the core of quantum computing.

The work, described in a cover story in the journal Nano Letters, explains how four years of continuous experimentation led to a novel method to design and build a unique, tiny sandwich composed of distinct atomic layers.

One slice of the microscopic structure is made of dysprosium titanate, an inorganic compound used in nuclear reactors to trap radioactive materials and contain elusive magnetic monopole particles, while the other is composed of pyrochlore iridate, a new magnetic semimetal mainly used in today's experimental research due to its distinctive electronic, topological and magnetic properties.

Individually, both materials are often considered "impossible" materials due to their unique properties that challenge conventional understanding of quantum physics.

The construction of the exotic sandwich structure sets the stage for scientific explorations in what is referred to as the interface, the area where the materials meet, in the atomic scale.

This work provides a new way to design entirely new artificial two-dimensional quantum materials, with the potential to push quantum technologies and provide deeper insight into their fundamental properties in ways that were previously impossible.

Mikhail Kareev et al, Epitaxial Stabilization of a Pyrochlore Interface between Weyl Semimetal and Spin Ice, Nano Letters (2025). DOI: 10.1021/acs.nanolett.4c03969

Comment by Dr. Krishna Kumari Challa yesterday

Patients with implants also exhibited higher levels of chromium, titanium, niobium, and zirconium in blood and serum. In cerebrospinal fluid, titanium, niobium, and zirconium levels were significantly elevated, but only when serum levels of these metals were also increased. This is an important finding as it supports the accuracy of less invasive blood sampling as an indicator of possible cerebrospinal fluid inundation.

Patients with implant components containing cobalt-chromium-molybdenum alloys had the highest cerebrospinal fluid concentrations of both cobalt and chromium. Cobalt levels in cerebrospinal fluid were significantly elevated even among patients with implants in place for less than ten years. Pain in the joint containing the implant was also associated with higher cobalt levels in cerebrospinal fluid.

No increase in cerebrospinal fluid metal levels was observed in patients with implants lacking cobalt-chromium-molybdenum components. Patients with cemented implants showed elevated levels of zirconium in blood and serum, though not in cerebrospinal fluid. Aluminum did not appear elevated in the implant group despite being present in certain implant alloys.
Blood-brain barrier integrity, assessed by serum S-100B levels, appeared unaffected and uncompromised in the implant group. Among those with elevated cerebrospinal fluid cobalt or zirconium, serum S-100B levels were lower than in matched controls.

Findings indicate that metal particles released from joint implants can accumulate in the central nervous system, especially those containing cobalt-chromium-molybdenum.
Results suggest that arthroplasty-related metal exposure is not confined to local tissues but extends systemically and may involve the brain. While blood-brain barrier dysfunction was not evident, the presence of these metals in cerebrospinal fluid raises questions about long-term neurological safety.

Anastasia Rakow et al, Metal Concentrations in Blood and Cerebrospinal Fluid of Patients With Arthroplasty Implants, JAMA Network Open (2025). DOI: 10.1001/jamanetworkopen.2025.2281

Part 2

Comment by Dr. Krishna Kumari Challa yesterday

Implant-derived metals found in cerebrospinal fluid

New research has found that metal particles from artificial joint implants can enter the central nervous system and accumulate in cerebrospinal fluid, raising concerns about potential neurological effects.

Joint replacement surgery has transformed orthopedic care, improving mobility and quality of life for millions of people. Modern implants, made from combinations of metals, are designed for durability and biocompatibility.

Over time, wear and corrosion of these materials can release microscopic particles into surrounding tissue. These byproducts have been linked to problems near the implant  site, including inflammation, tissue damage, and loosening of the joint.

Emerging concerns point to the possibility of metal particles entering the bloodstream and affecting organs far from the implant. Case reports have described serious effects on the heart, thyroid, and nervous system in patients with elevated levels of certain metals, particularly cobalt and chromium. Neurological changes have been reported in some patients following joint replacement.

Previous research has largely focused on these  metals and has relied on blood and serum measurements, leaving open the question of whether such particles reach the central nervous system.

In the study, "Metal Concentrations in Blood and Cerebrospinal Fluid of Patients With Arthroplasty Implants," published in JAMA Network Open, researchers conducted a single-site cross-sectional study to determine whether metals from joint implants can be found in cerebrospinal fluid and bloodstream.

A cohort was assessed of 204 adult participants, 102 with an existing large joint implant (median age 71.7) and 102 in a control group that had never received joint replacement surgery (median age 67.2).

Samples were collected during elective surgery under spinal anesthesia or during lumbar puncture for routine diagnostic or therapeutic reasons. Inductively coupled plasma mass spectrometry measured concentrations of ten metals in blood, serum, and cerebrospinal fluid, including cobalt, chromium, titanium, niobium, zirconium, and others known to be used in implant materials.

Cobalt levels in cerebrospinal fluid were significantly higher in patients with joint implants than in matched controls. Median cobalt concentrations were 0.03 μg/L in the implant group and 0.02 μg/L in the control group. Strong correlations were observed between cobalt levels in cerebrospinal fluid and those in serum and whole blood, suggesting systemic exposure may be reaching the central nervous system.

Part 1

Comment by Dr. Krishna Kumari Challa on Tuesday

How Microorganisms looks under the microscope

Comment by Dr. Krishna Kumari Challa on Tuesday

How perceptions are influenced by expectations: Songbird study draws parallels with human speech processing

Past neuroscience and psychology studies have shown that people's expectations of the world can influence their perceptions, either by directing their attention to expected stimuli or by reducing their sensitivity (i.e., perceptual acuity) to variations within the categories of stimuli we expect to be exposed to.

Researchers carried out a study involving songbirds aimed at better understanding how expectation-fueled biases in perception shape brain activity and behaviour.  

Their findings, published in Nature Neuroscience, suggest that the perceptions of songbirds, like those of humans, are influenced by expectations, with peripheral sensory systems utilizing expectations to enhance sensory perception and retain high-fidelity representations of the world.

Human speakers are known to have different voices, while also pronouncing many words differently. Past studies suggest that the human brain possesses robust underlying mechanisms designed to address these differences, by grouping speech sounds into stable perceptual categories, a process referred to as "categorical perception". 

One of these mechanisms is that we use context to cue and bias our perception.

The researchers examined the vocal behaviour and perceptions of songbirds. This is because songbirds are known to share many similarities with humans in terms of their vocal behaviour, thus studying them can help to better understand human speech and speech-related perceptions.

The team's initial experiments utilizing synthesized birdsongs showed that, similarly to humans who are listening to others speak, the perceptions of songbirds while listening to birdsongs are biased by their expectations.

Overall, this study confirmed the hypothesis that the song perceptions of songbirds closely resemble the speech perceptions of humans. Specifically, it gathered strong evidence suggesting that the vocal perceptions of songbirds are also biased and influenced by expectations.

The second important finding of this study emerged from the team's second experiment probing the neural basis of context-dependent categorical perception in songbirds. While their first experiment showed that the birds' expectations influenced how they classified songs, the second was aimed at determining whether the birds' sensory systems reflected this shift in perception.

The findings showed that  the sensory brain appears to use expectation in a more clever way, by rededicating neural responses to focusing on relevant, expected signals, improving perceptual acuity.

"It then leaves the bias to downstream processing like motor and decision-making regions of the brain. In this way, the brain can retain high-fidelity, unbiased, representations of the world, while still incorporating bias to make optimal decisions.

Tim Sainburg et al, Expectation-driven sensory adaptations support enhanced acuity during categorical perception, Nature Neuroscience (2025). DOI: 10.1038/s41593-025-01899-1.

**

• ‹ Previous
• 1
• 2
• 3
• 4
• …
• 1043
• Next ›
• Page