Connect with us
[adrotate group="1"]

Science & Health

How does tooth enamel last a lifetime?

Tooth enamel is the hardest substance in the human body, but, until now, no one knew how it managed to last a lifetime. The authors of a recent study conclude that enamel’s secret lies in the imperfect alignment of crystals.Using new imaging technology, scientists have unlocked the secrets of enamel. If we cut our skin…

Published

on

How does tooth enamel last a lifetime?

Tooth enamel is the hardest substance in the human body, but, until now, no one knew how it managed to last a lifetime. The authors of a recent study conclude that enamel’s secret lies in the imperfect alignment of crystals.Using new imaging technology, scientists have unlocked the secrets of enamel.

If we cut our skin or break a bone, these tissues will repair themselves; our bodies are excellent at recovering from injury.

Tooth enamel, however, cannot regenerate, and the oral cavity is a hostile environment.

Every mealtime, enamel is put under incredible stress; it also weathers extreme changes in both pH and temperature.

Despite this adversity, the tooth enamel that we develop as a child remains with us throughout our days.

Researchers have long been interested in how enamel manages to stay functional and intact for a lifetime.

As one of the authors of the latest study, Prof. Pupa Gilbert from the University of Wisconsin–Madison puts it, “How does it prevent catastrophic failure?”

The secrets of enamel

With assistance from researchers at the Massachusetts Institute of Technology (MIT) in Cambridge and the University of Pittsburgh, PA, Prof. Gilbert took a detailed look at the structure of enamel.

The team of scientists has now published the results of its study in the journal Nature Communications.

Enamel is made up of so-called enamel rods, which consist of hydroxyapatite crystals. These long, thin enamel rods are around 50 nanometers wide and 10 micrometers long.

By using cutting edge imaging technology, the scientists could visualize how individual crystals in tooth enamel are aligned. The technique, which Prof. Gilbert designed, is called polarization-dependent imaging contrast (PIC) mapping.

Before the advent of PIC mapping, it was impossible to study enamel with this level of detail. “[Y]ou can measure and visualize, in color, the orientation of individual nanocrystals and see many millions of them at once,” explains Prof. Gilbert.

“The architecture of complex biominerals, such as enamel, becomes immediately visible to the naked eye in a PIC map.”

When they viewed the structure of enamel, the researchers uncovered patterns. “By and large, we saw that there was not a single orientation in each rod, but a gradual change in crystal orientations between adjacent nanocrystals,” explains Gilbert. “And then the question was, ‘Is this a useful observation?'”

The importance of crystal orientation

To test whether the change in crystal alignment influences the way that enamel responds to stress, the team recruited help from Prof. Markus Buehler of MIT. Using a computer model, they simulated the forces that hydroxyapatite crystals would experience when a person chews.

Within the model, they placed two blocks of crystals next to each other so that the blocks touched along one edge. The crystals within each of the two blocks were aligned, but where they came in contact with the other block, the crystals met at an angle.

Throughout several trials, the scientists altered the angle at which the two blocks of crystals met. If the researchers perfectly aligned the two blocks at the interface where they met, a crack would appear when they applied pressure.

When the blocks met at 45 degrees, it was a similar story; a crack appeared at the interface. However, when the crystals were only slightly misaligned, the interface deflected the crack and prevented it from spreading.

This finding spurred further investigation. Next, Prof. Gilbert wanted to identify the perfect angle of interface for maximum resilience. The team could not use computer models to investigate this question, so Prof. Gilbert put her trust in evolution. “If there is an ideal angle of misorientation, I bet it’s the one in our mouths,” she decided.

To investigate, co-author Cayla Stifler returned to the original PIC mapping information and measured the angles between adjacent crystals. After generating millions of data points, Stifler found that 1 degree was the most common size of misorientation, and the maximum was 30 degrees.

This observation agreed with the simulation — smaller angles seem better able to deflect cracks.

“Now we know that cracks are deflected at the nanoscale and, thus, can’t propagate very far. That’s the reason our teeth can last a lifetime without being replaced.”

Prof. Pupa Gilbert

Read More

Continue Reading
Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

*

code

Science & Health

Vitamin D sufficiency may reduce complications of COVID-19

A recent small-scale study has concluded that hospitalized patients with COVID-19 are less likely to have life threatening complications if they have sufficient vitamin D levels.A new study demonstrates that people with sufficient levels of vitamin D are less likely to develop life threatening COVID-19 complications when hospitalized with the disease.The research, published in the…

Published

on

By

Vitamin D sufficiency may reduce complications of COVID-19

A recent small-scale study has concluded that hospitalized patients with COVID-19 are less likely to have life threatening complications if they have sufficient vitamin D levels.A new study demonstrates that people with sufficient levels of vitamin D are less likely to develop life threatening COVID-19 complications when hospitalized with the disease.The research, published in the journal PLOS ONE, could be valuable for doctors attempting to reduce the mortality rates of COVID-19 in the absence of an effective vaccine.If further studies back up these findings, vitamin D supplements might offer a cost-effective way to limit the risk of severe COVID-19. It is important to note that this recent study has several limitations, which we address below.Stay informed with live updates on the current COVID-19 outbreak and visit our coronavirus hub for more advice on prevention and treatment.Since the sudden emergence of the virus SARS-CoV-2 and the disease that it causes, COVID-19, scientists have paid a great deal of attention to the development of a vaccine. Experts consider a vaccine to be crucial in reducing the effects of the virus, even if it is not yet clear to what extent an initial vaccine would moderate rates of transmission and infection.Alongside the endeavor to develop a vaccine, researchers are also focusing on developing effective COVID-19 treatments. Even if none can make a person immune to the virus, treatments may be able to reduce the disease’s severity.The Food and Drug Administration (FDA) have approved two drugs as treatments for COVID-19: remdesivir and dexamethasone.Another candidate is vitamin D. Research has suggested that it might, in theory, be effective, but corroborating this requires further efforts.Rather than analyzing the effects of vitamin D as COVID-19 treatment, the researchers behind the present study looked at the effects of a person’s vitamin D levels on the severity of the disease.To do so, they analyzed data from patients with confirmed COVID-19 who had been admitted to the Sina Hospital, in Tehran, Iran.Of the 611 people admitted with confirmed COVID-19 before May 1, 2020, there were records of the 25-hydroxyvitamin D levels, an indication of overall vitamin D levels, for 235 patients. Their mean age was 58.7 years, ranging from 20–90 years, and 37.4% were older than 65.The researchers classified the patients into two groups: those with vitamin D levels of at least 30 nanograms per milliliter (ng/ml) — an amount considered sufficient by the Endocrine Society — and those with lower values.They then analyzed the severity of the patients’ COVID-19 signs and symptoms using guidelines from the Centers for Disease Control and Prevention (CDC). Severe or critical disease might involve a range of issues, including shortness of breath, respiratory failure, or a significantly reduced blood oxygen level.After cross-checking the patients’ vitamin D levels with the severity of their COVID-19 symptoms and accounting for confounding factors, the researchers found that having a vitamin D level of above 30 ng/ml was significantly associated with having less severe COVID-19.Among the 235 patients with confirmed COVID-19, only 32.8% had sufficient levels of the vitamin.The researchers also found that the patients with sufficient vitamin D had higher blood lymphocyte counts and lower levels of C-reactive protein in their blood — both of which indicate a positive immune response.The researchers speculate that this may have reduced the likelihood of developing cytokine storm, which can cause acute respiratory distress syndrome in COVID-19 patients, sometimes resulting in death.The findings highlight, the researchers say, that vitamin D sufficiency may be important in the eventuality that people develop COVID-19 alongside another respiratory disease, such as influenza.According to the study’s corresponding author, Dr. Michael F. Holick, director of the General Clinical Research Unit at the medical campus of Boston University, in Massachusetts, “There is great concern that the combination of an influenza infection and a coronal viral infection could substantially increase hospitalizations and death due to complications from these viral infections.”For the researchers, their findings suggest that vitamin D supplementation would be valuable. As Dr. Holick notes: “Because vitamin D deficiency and insufficiency is so widespread in children and adults in the United States and worldwide, especially in the winter months, it is prudent for everyone to take a vitamin D supplement to reduce [the] risk of being infected and having complications from COVID-19.”It is worthing noting the present study’s limitations. First, the researchers only had access to a relatively small number of patients. Before drawing solid conclusions, scientists need to carry out much larger studies.Also, various issues can influence both vitamin D status and COVID-19 severity, such as socioeconomic factors and smoking status. The scientists accounted for neither of these in their analysis.Also, because the study was cross-sectional, the researchers could not prove that vitamin D insufficiency caused an increase in disease severity. To address these limitations, the researchers call for “large-scale studies and randomized clinical trials.”For live updates on the latest developments regarding the novel coronavirus and COVID-19, click here.
Read More

Continue Reading

Science & Health

Video gaming as a child related to improvements in memory

A new study exploring the link between video games and cognition finds that playing video games as a child can improve a person’s working memory years later on specific tasks.Video games can be a contentious topic, particularly among parents or caregivers who may be concerned about the effects of spending hours in front of the…

Published

on

By

Video gaming as a child related to improvements in memory

A new study exploring the link between video games and cognition finds that playing video games as a child can improve a person’s working memory years later on specific tasks.Video games can be a contentious topic, particularly among parents or caregivers who may be concerned about the effects of spending hours in front of the console.Yet, it seems that some video gaming could actually be beneficial. Recent studies have shown that playing video games could improve learning and may even protect against dementia in older adults.The authors of a recent review of the evidence on video games concluded that gaming could have benefits for both cognitive and emotional skills.In a new study, which features in the journal Frontiers in Human Neuroscience, researchers from the Universitat Oberta de Catalunya in Barcelona trained volunteers to play “Super Mario 64” — a game that researchers have previously shown to induce structural changes in parts of the brain associated with executive function and spatial memory.The new study found that people who played video games as children showed greater improvements in their working memory than those who did not, suggesting that video games can have long lasting benefits for cognition.This study combined video game playing with transcranial magnetic stimulation (TMS), a noninvasive form of brain stimulation that scientists have studied as a treatment for mood disorders. In 2008, the Food and Drug Administration (FDA) approved its use for the treatment of major depression when other approaches have failed.Studies have also shown TMS to boost cognitive performance under some conditions, with more than 60 studies reporting that the treatment led to significant improvements in cognition, including in working memory (holding and manipulating information over a short period).The researchers behind the new study wanted to find out whether combining video game training and TMS could enhance cognitive function more than either element alone.They asked 27 healthy volunteers, with an average age of 29 years, to take part in 10 video game training sessions, during each of which they played “Super Mario 64” for an hour and a half.At the end of each session, the researchers applied TMS to part of the prefrontal cortex, which is at the front of the brain and is important for complex cognitive functions, such as working memory and reasoning. The researchers assessed the cognitive function of the participants before the study started, at the end of the 10 sessions, and 15 days after this.They assessed a range of cognitive functions, including reaction time, working memory, attention span, visuospatial skills, and problem-solving.Although the results overall showed very limited changes in cognitive ability, which seemed to result only from the video game training and not the TMS, the researchers did find that participants with early experience of video gaming had improved working memory.“People who were avid gamers before adolescence, despite no longer playing, performed better with the working memory tasks, which require mentally holding and manipulating information to get a result,” explains lead author of the study Dr. Marc Palaus, Ph.D.People with prior experience of playing video games (but not the actual game in the study) also showed improvements in processing and were better able to focus on relevant stimuli during the tasks.“People who played regularly as children performed better from the outset in processing 3D objects, although these differences were mitigated after the period of training in video gaming, when both groups showed similar levels,” adds Dr. Palaus.The results suggest that video games may induce cognitive changes that last for years after people have stopped playing.Dr. Palaus says that video games that provide motivation — making the player want to keep on playing — and also get more difficult to stay challenging require intensive use of brain resources, which makes them ideal for boosting cognitive ability.“Video games are a perfect recipe for strengthening our cognitive skills, almost without our noticing.”– Dr. Marc Palaus, Ph.D. It is important to note that this study included a small number of participants who were all healthy, young, and highly educated, meaning that the findings might not be more widely applicable.Talking about the findings of their study, Dr. Palaus stressed that these improvements only have a limited effect on the performance of other activities not linked to video gaming, as is the case with most cognitive training.
Read More

Continue Reading

Science & Health

Lax gun laws in neighboring states may increase firearm deaths

A US study suggests strong gun control regulations reduce a state’s firearm deaths, but having neighbors with more lenient laws undermines their effect.Share on PinterestNew research suggests that one state’s lax gun laws could undo the effects of its neighbor’s stricter firearm regulations.In 2017, 39,773 people died from gun-related injuries in the United States, according…

Published

on

By

Lax gun laws in neighboring states may increase firearm deaths

A US study suggests strong gun control regulations reduce a state’s firearm deaths, but having neighbors with more lenient laws undermines their effect.Share on PinterestNew research suggests that one state’s lax gun laws could undo the effects of its neighbor’s stricter firearm regulations.In 2017, 39,773 people died from gun-related injuries in the United States, according to the National Center for Injury Prevention and Control.Overall, research indicates that stronger state laws governing the sale and ownership of firearms reduce firearm-related deaths. However, some states have relatively high rates of gun deaths despite strict regulations. To investigate why this might be the case, scientists at the University of Alabama at Birmingham, and the Boston University School of Public Health at Boston, MA, looked into the effects of firearm laws in neighboring states.They used the Web-based Injury Statistics Query and Reporting System to obtain figures for firearm-related deaths in the 48 adjacent U.S. states from 2000 to 2017. There were 578,022 firearm deaths in total, including homicides and suicides, but excluding deaths due to shootings by police or other law enforcement agents. The scientists also searched the State Firearm Laws Database for laws in each state regarding:background checksgun dealer regulationsbuyer regulationsgun-trafficking lawsThe team used the number of these laws as a proxy for gun control strength in each state.If you would like to check your registration status or register to vote, we have added some useful links at the bottom of this article.Overall, stronger state gun laws were associated with reduced firearm deaths, but having a neighboring state with more permissive laws undermined this protective effect.Larger policy differences across state borders were associated with increased gun-related deaths, suicides, and homicides, though the results were statistically stronger for suicide than homicide.The authors conclude:“This study adds to the growing literature emphasizing the role played by neighboring states’ firearm regulations in addition to own-state firearm regulations in firearm deaths. Failing to account for neighboring states with weaker laws, in some instances, can make a state’s own regulations appear less effective in reducing firearm deaths.”The scientists calculate that, on average, failure to account for weaker firearm laws in neighboring states make it appear as though a state’s laws were about 20% less effective at reducing deaths than they really were.They report their findings in the American Journal of Preventive Medicine.The researchers write that higher prices and strong marketing regulations can lead consumers to purchase firearms in adjacent, relatively unregulated markets. They say these are a frequent source of the guns used in crimes.They believe their work supports the case for more cooperative legislation between neighboring states and at the federal level.“I think the main message of this study is that to solve a nationwide problem we need to think of a nationwide or at least a regional-level (i.e. multistate) approach, like we may also need for the COVID-19 pandemic,” says Dr. Ye Liu, who is a doctoral student in the Department of Health Care Organization and Policy at the University of Alabama and the first author of the study. “An ‘each state on its own’ approach is ultimately inadequate to address one of the biggest public health challenges in this country,” Dr. Liu adds.The authors acknowledge the number of gun-control laws may not perfectly reflect the strictness of a state’s regulations. In addition, they note states may vary in how diligently they enforce these laws.They call for further studies that might use alternative measures of regulatory strength, focus on specific categories of law, or explore the effects of regulations in more distant states. To check your voter registration status, click here to visit VoteAmerica, a nonprofit, nonpartisan organization dedicated to increasing voter turnout. They can also help you register to vote, vote by mail, request an absentee ballot, or find your polling place.
Read More

Continue Reading
error: Content is protected !!