What to do when a crown comes off

A lost filling is one of the most common issues dentists are called on to fix. Most fillings aren’t designed to last a lifetime, so if you have fillings, there’s a very good chance you’ll have to have them replaced at some point. Regular checkups are a good way to prevent lost fillings, but if your filling falls out unexpectedly there’s no need to panic. Crown Came Off  has a great post about it here

Curcumin Shows Promise in Attacking Parkinson’s Disease

EAST LANSING, Mich. — Curcumin, a compound found in the spice turmeric, is proving effective at preventing clumping of a protein involved in Parkinson’s disease, says a Michigan State University researcher.

A team of researchers led by Basir Ahmad, an MSU postdoctoral researcher, demonstrated earlier this year that slow-wriggling alpha-synuclein proteins are the cause of clumping, or aggregation, which is the first step of diseases such as Parkinson’s. A new study led by Ahmad, which appears in the current issue of the Journal of Biological Chemistry, shows that curcumin can help prevent clumping.

“Our research shows that curcumin can rescue proteins from aggregation, the first steps of many debilitating diseases,” said Lisa Lapidus, MSU associate professor of physics and astronomy who co-authored the paper with Ahmad. “More specifically, curcumin binds strongly to alpha-synuclein and prevents aggregation at body temperatures.”

Lapidus’ lab uses lasers to study protein folding. Proteins are chains of amino acids that do most of the work in cells. Scientists understand protein structure, but they don’t know how they are built – a process known as folding. Lapidus’ team is shedding light on the process by correlating the speed at which protein folds with its tendency to clump or bind with other proteins.

When curcumin attaches to alpha-synuclein it not only stops clumping, but it also raises the protein’s folding or reconfiguration rate. By bumping up the speed, curcumin moves the protein out of a dangerous speed zone allowing it to avoid clumping with other proteins.

Finding a compound that can fix a protein when it first begins to misfold can lead scientists to identify drugs that can treat certain diseases. Doctors won’t be prescribing curcumin pills any time soon, though, Lapidus said.

“Curcumin’s usefulness as an actual drug may be pretty limited since it doesn’t go into the brain easily where this misfolding is taking place,” she said. “But this kind of study showcases the technique of measuring reconfiguration and opens the door for developing drug treatments.”

Study Shows Cell Phone Use During Pregnancy May Contribute to Behavioral Disorders in Offspring

New Haven, Conn. — Exposure to radiation from cell phones during pregnancy affects the brain development of offspring, potentially leading to hyperactivity, Yale School of Medicine researchers have determined.

The results, based on studies in mice, are published in the March 15 issue of Scientific Reports, a Nature publication.

“This is the first experimental evidence that fetal exposure to radiofrequency radiation from cellular telephones does in fact affect adult behavior,” said senior author Hugh S. Taylor, M.D., professor and chief of the Division of Reproductive Endocrinology and Infertility in the Department of Obstetrics, Gynecology & Reproductive Sciences.

Taylor and co-authors exposed pregnant mice to radiation from a muted and silenced cell phone positioned above the cage and placed on an active phone call for the duration of the trial. A control group of mice was kept under the same conditions but with the phone deactivated.

The team measured the brain electrical activity of adult mice that were exposed to radiation as fetuses, and conducted a battery of psychological and behavioral tests. They found that the mice that were exposed to radiation tended to be more hyperactive and had reduced memory capacity. Taylor attributed the behavioral changes to an effect during pregnancy on the development of neurons in the prefrontal cortex region of the brain.

Attention deficit hyperactivity disorder (ADHD), is a developmental disorder associated with neuropathology localized primarily to the same brain region, and is characterized by inattention and hyperactivity.

“We have shown that behavioral problems in mice that resemble ADHD are caused by cell phone exposure in the womb,” said Taylor. “The rise in behavioral disorders in human children may be in part due to fetal cellular telephone irradiation exposure.”

Taylor said that further research is needed in humans to better understand the mechanisms behind these findings and to establish safe exposure limits during pregnancy. Nevertheless, he said, limiting exposure of the fetus seems warranted.

First author Tamir Aldad added that rodent pregnancies last only 19 days and offspring are born with a less-developed brain than human babies, so further research is needed to determine if the potential risks of exposure to radiation during human pregnancy are similar.

“Cell phones were used in this study to mimic potential human exposure but future research will instead use standard electromagnetic field generators to more precisely define the level of exposure,” said Aldad.

 

Scientists Develop First Direct Measurement of Earth’s Rotation

The Earth wobbles. Like a spinning top touched in mid-spin, its rotational axis fluctuates in relation to space. This is partly caused by gravitation from the sun and the moon. At the same time, the Earth’s rotational axis constantly changes relative to the Earth’s surface. On the one hand, this is caused by variation in atmospheric pressure, ocean loading and wind. These elements combine in an effect known as the Chandler wobble to create polar motion. Named after the scientist who discovered it, this phenomenon has a period of around 435 days. On the other hand, an event known as the “annual wobble” causes the rotational axis to move over a period of a year. This is due to the Earth’s elliptical orbit around the sun. These two effects cause the Earth’s axis to migrate irregularly along a circular path with a radius of up to six meters.

Capturing these movements is crucial to create a reliable coordinate system that can feed navigation systems or project trajectory paths in space travel. “Locating a point to the exact centimeter for global positioning is an extremely dynamic process – after all, at our latitude, we are moving at around 350 meters to the east per second,” explains Prof. Karl Ulrich Schreiber who directed the project in TUM’s Research Section Satellite Geodesy. The orientation of the Earth’s axis relative to space and its rotational velocity are currently established in a complicated process that involves 30 radio telescopes around the globe. Every Monday and Thursday, eight to twelve of these telescopes alternately measure the direction between Earth and specific quasars. Scientists assume that these galaxy nuclei never change their position and can therefore be used as reference points. The geodetic observatory Wettzell, which is run by TUM and Germany’s Federal Agency for Cartography (BKG), is also part of this process.

In the mid-1990s, scientists of TUM and BKG joined forces with researchers at New Zealand’s University of Canterbury to develop a simpler method that would be capable of continuously tracking the Chandler wobble and annual wobble. “We also wanted to develop an alternative that would enable us to eliminate any systematic errors,” continues Schreiber. “After all, there was always a possibility that the reference points in space were not actually stationary.” The scientists had the idea of building a ring laser similar to ones used in aircraft guidance systems – only millions of times more exact. “At the time, we were almost laughed off. Hardly anyone thought that our project was feasible,” says Schreiber.

Yet at the end of the 1990s, work on the world’s most stable ring laser got underway at the Wettzell observatory. The installation comprises two counter-rotating laser beams that travel around a square path with mirrors in the corners, which form a closed beam path (hence the name ring laser). When the assembly rotates, the co-rotating light has farther to travel than the counter-rotating light. The beams adjust their wavelengths, causing the optical frequency to change. The scientists can use this difference to calculate the rotational velocity the instrumentation experiences. In Wettzell, it is the Earth that rotates, not the ring laser. To ensure that only the Earth’s rotation influences the laser beams, the four-by-four-meter assembly is anchored in a solid concrete pillar, which extends six meters down into the solid rock of the Earth’s crust.

The Earth’s rotation affects light in different ways, depending on the laser’s location. “If we were at one of the poles, the Earth and the laser’s rotational axes would be in complete synch and their rotational velocity would map 1:1,” details Schreiber. “At the equator, however, the light beam wouldn’t even notice that the Earth is turning.” The scientists therefore have to factor in the position of the Wettzell laser at the 49th degree of latitude. Any change in the Earth’s rotational axis is reflected in the indicators for rotational velocity. The light’s behavior therefore reveals shifts in the Earth’s axis.

“The principle is simple,” adds Schreiber. “The biggest challenge was ensuring that the laser remains stable enough for us to measure the weak geophysical signal without interference – especially over a period of several months.” In other words, the scientists had to eliminate any changes in frequency that do not come from the Earth’s rotation. These include environmental factors such as atmospheric pressure and temperature. They relied predominantly on a ceramic glass plate and a pressurized cabin to achieve this. The researchers mounted the ring laser on a nine-ton Zerodur base plate, also using Zerodur for the supporting beams. They chose Zerodur as it is extremely resistant to changes in temperature. The installation is housed in a pressurized cabin, which registers changes in atmospheric pressure and temperature (12 degrees) and automatically compensates for these. The scientists sunk the lab five meters below ground level to keep these kinds of ambient influences to a minimum. It is insulated from above with layers of Styrodur and clay, and topped by a four-meter high mound of Earth. Scientists have to pass through a twenty-meter tunnel with five cold storage doors and a lock to get to the laser.

Under these conditions, the researchers have succeeded in corroborating the Chandler and annual wobble measurements based on the data captured by radio telescopes. They now aim to make the apparatus more accurate, enabling them to determine changes in the Earth’s rotational axis over a single day. The scientists also plan to make the ring laser capable of continuous operation so that it can run for a period of years without any deviations. “In simple terms,” concludes Schreiber, “in future, we want to be able to just pop down into the basement and find out how fast the Earth is accurately turning right now.”

 

NASA’s Lunar Reconnaissance Orbiter Offer Sharpest Views of Apollo Landing Sites Ever Seen

TEMPE, Ariz. – The Arizona State University team that oversees the imaging system on board NASA’s Lunar Reconnaissance Orbiter has released the sharpest images ever taken from space of the Apollo 12, 14 and 17 sites, more clearly showing the paths made when the astronauts explored these areas.

The higher resolution of these images is possible because of adjustments made to LRO’s elliptical orbit. On August 10 a special pair of stationkeeping maneuvers were performed in place of the standard maneuvers, lowering LRO from its usual altitude of 50 kilometers (about 31 miles) to an altitude that dipped as low as 21 kilometers (nearly 13 miles) as it passed over the Moon’s surface.

“The new low-altitude Narrow Angle Camera images sharpen our view of the Moon’s surface,” says Mark Robinson, the Principal Investigator for LROC and professor in the School of Earth and Space Exploration in ASU’s College of Liberal Arts and Sciences. The LROC imaging system consists of two Narrow Angle Cameras (NACs) to provide high-resolution images, and a Wide Angle Camera (WAC) to provide 100-meter resolution images in seven color bands over a 57-km swath.

“A great example is the sharpness of the rover tracks at the Apollo 17 site,” Robinson says. “In previous images the rover tracks were visible, but now they are sharp parallel lines on the surface!”

The maneuvers were carefully designed so that the lowest altitudes occurred over some of the Apollo landing sites.

At the Apollo 17 site, the tracks laid down by the lunar rover are clearly visible, along with distinct trails left in the Moon’s thin soil when the astronauts exited the lunar modules and explored on foot. In the Apollo 17 image, the foot trails—including the last path made on the Moon by humans—are more easily distinguished from the dual tracks left by the lunar rover, which remains parked east of the lander.

At each site, trails also run to the west of the landers, where the astronauts placed the Apollo Lunar Surface Experiments Package (ALSEP), providing the first insights into the Moon’s internal structure and first measurements of its surface pressure and the composition of its atmosphere.

One of the details that shows up is a bright L-shape in the Apollo 12 image marking the locations of cables running from ALSEP’s central station to two of its instruments. Though the cables are much too small to be resolved, they show up because the material they are made from reflects light very well and thus stand out against the dark lunar soil.

The spacecraft has remained in this orbit for 28 days, long enough for the Moon to completely rotate underneath, thus also allowing full coverage of the surface by LROC’s Wide Angle Camera. This low-orbit cycle ends today when the spacecraft will be returned to the 50-kilometer orbit.