Russian Supply Rocket Malfunctions, Breaks Up Over Siberia En Route To ISS

Slashdot - Fri, 02/12/2016 - 7:00am
An anonymous reader quotes a report from NPR: An unmanned cargo rocket bound for the International Space Station was destroyed after takeoff on Thursday. The Russian rocket took off as planned from Baikonur, Kazahkstan, on Thursday morning but stopped transmitting data about six minutes into its flight, as NPR's Rae Ellen Bichell reported: "'Russian officials say the spacecraft failed [...] when it was about 100 miles above a remote part of Siberia. The ship was carrying more than 2 1/2 tons of supplies -- including food, fuel and clothes. Most of that very likely burned up as the unmanned spacecraft fell back toward Earth. NASA says the six crew members on board the International Space station, including two Americans, are well stocked for now.'" This is the fourth botched launch of an unmanned Russian rocket in the past two years. Roscomos officials wrote in an update today: "According to preliminary information, the contingency took place at an altitude of about 190 km over remote and unpopulated mountainous area of the Republic of Tyva. The most of cargo spacecraft fragments burned in the dense atmosphere. The State Commission is conducting analysis of the current contingency. The loss of the cargo ship will not affect the normal operations of the ISS and the life of the station crew."

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Categories: Science

See Venus and the Moon Pair Up Saturday Night

Space.com - Fri, 02/12/2016 - 6:11am
Venus and the crescent moon will get together in the sky Saturday evening (Dec. 3), making for an eye-catching sight.
Categories: Science

All Hab Systems Go at the Mars Desert Research Station

Space.com - Fri, 02/12/2016 - 6:00am
Annalea Beattie talks about life and work inside the habitat in the Utah Desert that she and her fellow Mars 160 crewmembers call home.
Categories: Science

Tracking large neural networks in the brain by making neurons glow

Kurzweil AI - Thu, 01/12/2016 - 4:43am

A neuron glows with bioluminescent light produced by a new genetically engineered sensor. (credit: Johnson Lab, Vanderbilt University)

A new kind of bioluminescent sensor developed by Vanderbilt scientists causes individual brain cells to glow in the dark, giving neuroscientists a new tool to track what’s happening in large neural networks in the brain.

The sensor is a genetically modified form of luciferase, the enzyme that fireflies and other species use to produce light.

Traditional electrical techniques for recording the activity of neurons are limited to small numbers of neurons at a time. Instead, the new sensors use a new combination of optical techniques to record the activity of hundreds of neurons at the same time, according to Carl Johnson, Stevenson Professor of Biological Sciences, who headed the effort.

The research is a spinoff of the team’s research in bioluminescence* in the green alga Chlamydomonas. Johnson and his colleagues realized that if they could combine luminescence with optogenetics (which uses light to control cells, particularly neurons), they could create a powerful new tool for studying brain activity.

To create the new sensor, Johnson and his collaborators first genetically modified a type of luciferase obtained from a luminescent species of shrimp so that it would light up when exposed to calcium ions (their level  pikes briefly when a neuron receives an impulse from one of its neighbors). Then they attached a virus that infects and genetically modifies neurons.

They tested their new calcium sensor with an optogenetic protein called channelrhodopsin that causes the calcium ion channels in the neuron’s outer membrane to open, flooding the cell with calcium. Using neurons grown in culture they found that the luminescent enzyme reacted visibly to the influx of calcium produced when the probe was stimulated by brief light flashes of visible light.


Vanderbilt University | Bioluminescent sensor causes brain cells to glow in the dark

To determine how well their sensor works with larger numbers of neurons, they inserted it into brain slices from mouse hippocampus containing thousands of neurons. In this case, they flooded the slices with an increased concentration of potassium ions, which causes the cell’s ion channels to open. Again, they found that the sensor responded to the variations in calcium concentrations by brightening and dimming.


Vanderbilt University | Optical sensor illuminates activity of neural network

“We’ve shown that the approach works,” Johnson said. “Now we have to determine how sensitive it is. We have some indications that it is sensitive enough to detect the firing of individual neurons, but we have to run more tests to determine if it actually has this capability.”

The research is described in a paper published in the open-access journal Nature Communications on Oct. 27 and was funded by the National Institutes of Health, the National Science Foundation, and a grant from the Vanderbilt Brain Institute.

* There have also been efforts in optical recording of neurons using fluorescence, but this requires a strong external light source which can cause the tissue to heat up and can interfere with some biological processes, particularly those that are light sensitive, Johnson explained. It would also interfere with the light used in optogenetics. In contrast, light in bioluminescence is produced by biochemical reactions (the light-emitting pigment luciferin and the enzyme luciferase).

Abstract of Coupling optogenetic stimulation with NanoLuc-based luminescence (BRET) Ca++ sensing

Optogenetic techniques allow intracellular manipulation of Ca++ by illumination of light-absorbing probe molecules such as channelrhodopsins and melanopsins. The consequences of optogenetic stimulation would optimally be recorded by non-invasive optical methods. However, most current optical methods for monitoring Ca++ levels are based on fluorescence excitation that can cause unwanted stimulation of the optogenetic probe and other undesirable effects such as tissue autofluorescence. Luminescence is an alternate optical technology that avoids the problems associated with fluorescence. Using a new bright luciferase, we here develop a genetically encoded Ca++ sensor that is ratiometric by virtue of bioluminescence resonance energy transfer (BRET). This sensor has a large dynamic range and partners optimally with optogenetic probes. Ca++ fluxes that are elicited by brief pulses of light to cultured cells expressing melanopsin and to neurons-expressing channelrhodopsin are quantified and imaged with the BRET Ca++ sensor in darkness, thereby avoiding undesirable consequences of fluorescence irradiation.

Categories: Science

Thu, 01/01/1970 - 12:00am