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guardian:

The UN Security Council has called for a ceasefire in the Israeli-Palestinian conflict centered on Gaza.

A council statement approved on Saturday by all 15 members calls for de-escalation of the violence, restoration of calm and a resumption of direct negotiations between Israel and the Palestinians aimed at achieving a comprehensive peace agreement based on a two-state solution. Full story here

"A ball of fire is seen following an Israeli air strike in Rafah, in the southern Gaza Strip. Photo: Said Khatib/AFP/Getty Images

neuromorphogenesis:

Nanoparticles may harm the brain

A simple change in electric charge may make the difference between someone getting the medicine they need and a trip to the emergency room—at least if a new study bears out. Researchers investigating the toxicity of particles designed to ferry drugs inside the body have found that carriers with a positive charge on their surface appear to cause damage if they reach the brain.

These particles, called micelles, are one type of a class of materials known as nanoparticles. By varying properties such as charge, composition, and attached surface molecules, researchers can design nanoparticles to deliver medicine to specific body regions and cell types—and even to carry medicine into cells. This ability allows drugs to directly target locations they would otherwise be unable to, such as the heart of tumors. Researchers are also looking at nanoparticles as a way to transport drugs across the blood-brain barrier, a wall of tightly connected cells that keeps most medication out of the brain. Just how safe nanoparticles in the brain are, however, remains unclear.

So Kristina Bram Knudsen, a toxicologist at the National Research Centre for the Working Environment in Copenhagen, and colleagues tested two types of micelles, which were made from different polymers that gave the micelles either a positive or negative surface charge. They injected both versions, empty of drugs, into the brains of rats, and 1 week later they checked for damage. Three out of the five rats injected with the positively charged micelles developed brain lesions. The rats injected with the negatively charged micelles or a saline control solution did not suffer any observable harm from the injections, the team will report in an upcoming issue of Nanotoxicology.

Knudsen speculates that one of the attributes that makes positive micelles and similar nanoparticles such powerful drug delivery systems may also be what is causing the brain damage. Because cells have a negative charge on their outside, they attract positively charged micelles and bring them into the cell. The micelles’ presence in the cell or alteration of the cell’s surface charge, she says, may disrupt the cell’s normal functioning.

Negatively charged nanoparticles can also enter cells, according to other research. However, they do so less readily and must be able to overcome the repulsion between themselves and the cell surface. It is possible that the reason the negatively charged micelles were not found to be toxic was that they did not invade cells to the same extent as the positively charged micelles. 

The findings are intriguing, says biomedical engineer Jordan Green of Johns Hopkins University in Baltimore, Maryland. But he cautions that there is no evidence that all positively charged nanoparticles behave this way. Other factors can also play a role in the toxicity of nanoparticles, adds pharmaceutical expert Jian-Qing Gao of Zhejiang University in Hangzhou, China. The size and concentration of the particles, as well as the strain of rat used, could all have influenced the results, he says.

openaccessarchaeology:

Lots of great Open Access (free to read) Archaeology articles:

Spatial Variables as Proxies for Modeling Cognition and Decision-Making in Archaeological Settings: A Theoretical Perspective
http://bit.ly/1hCaJGY

The Cathedral Church of St. David’s
http://bit.ly/14GEXqo

Open Source in archeologia: ArcheoFOSS
http://bit.ly/1nwTxJ4

Notice of an Earthen Jar, found in excavating the foundation of an old house in Leith.
http://bit.ly/1a9CaZ9

Senhora das Lapas: excavation of prehistoric cave burials in central Portugal
http://bit.ly/1nwTzR5

Learn more about Open Access and Archaeology at: http://bit.ly/YHuyFK

At some point you just have to let go of what you thought should happen and live in what is happening.

newsweek:

(via The Blood Harvest - Alexis C. Madrigal - The Atlantic)

Every drug certified by the FDA must be tested using LAL, a substance found only in horseshoe crab blood. Every single person in America who has ever had an injection has been protected by this ‘forgettable’ sea creature.

kidsneedscience:

On this day, March 1, 1896, Henri Becquerel discovered radioactivity.  Becquerel was born in Paris France into an illustrious scientific family, which produced four generations of scientists. He studied history at the École Polytechnique and engineering at the École des Ponts et Chaussées. In 1892, he became the third in his family to occupy the physics chair at the Muséum National d’Histoire Naturelle. In 1896, while investigating the work of Wilhelm Conrad Röntgen and phosphorescence in uranium salts, Becquerel accidentally discovered radioactivity. Becquerel wrapped a fluorescent substance potassium uranyl sulfate in photographic plates and black material in preparation for an experiment requiring bright sunlight. Prior to actually performing the experiment, however, Becquerel found that the photographic plates were already exposed, showing an image of the substance.  But it wasn’t until two years later that Pierre and Marie Curie saw radium glowing in a test tube, and they knew that they were seeing something new for which no word existed.  The word they coined,radioactive, was a combination of the Latin word radius meaning a ray and the French word actif from the Latin word actus meaning a doing, a driving, impulse; a part in a play.  The Curies were attempting to convey what they were seeing-energy radiating out from the material.  Today, radioactive decay is defined as the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles.  There are many types ofradioactivity classified today, but all fall under the larger definition of activity radiating out in rays.  This discovery (and work of the Curies) led Becquerel to investigate the spontaneous emission of nuclear radiation. In 1903 he shared the Nobel Prize in Physics with Marie and Pierre Curie for his pioneering work on radiation.

Today the becquerel (symbol Bq) (pronounced: ‘be-kə-rel) is the SI-derived unit of radioactivity. One Bq is defined as the activity of a quantity of radioactive material in which one nucleus decays per second.

Image of Henri Becquerel by Paul Nadar, image in the public domain.  Illustration of radioactive atom courtesy wikicommons.

(via sagansense)

neurosciencestuff:

Scientists wake up to causes of sleep disruption in Alzheimer’s disease

Being awake at night and dozing during the day can be a distressing early symptom of Alzheimer’s disease, but how the disease disrupts our biological clocks to cause these symptoms has remained elusive.

Now, scientists from Cambridge have discovered that in fruit flies with Alzheimer’s the biological clock is still ticking but has become uncoupled from the sleep-wake cycle it usually regulates. The findings – published in Disease Models & Mechanisms – could help develop more effective ways to improve sleep patterns in people with the disease.

People with Alzheimer’s often have poor biological rhythms, something that is a burden for both patients and their carers. Periods of sleep become shorter and more fragmented, resulting in periods of wakefulness at night and snoozing during the day. They can also become restless and agitated in the late afternoon and early evening, something known as ‘sundowning’.

Biological clocks go hand in hand with life, and are found in everything from single celled organisms to fruit flies and humans. They are vital because they allow organisms to synchronise their biology to the day-night changes in their environments.

Until now, however, it has been unclear how Alzheimer’s disrupts the biological clock. According to Dr Damian Crowther of Cambridge’s Department of Genetics, one of the study’s authors: “We wanted to know whether people with Alzheimer’s disease have a poor behavioural rhythm because they have a clock that’s stopped ticking or they have stopped responding to the clock.”

The team worked with fruit flies – a key species for studying Alzheimer’s. Evidence suggests that the A-beta peptide, a protein, is behind at least the initial stages of the disease in humans. This has been replicated in fruit flies by introducing the human gene that produces this peptide.

Taking a group of healthy flies and a group with this feature of Alzheimer’s, the researchers studied sleep-wake patterns in the flies, and how well their biological clocks were working.

They measured sleep-wake patterns by fitting a small infrared beam, similar to movement sensors in burglar alarms, to the glass tubes housing the flies. When the flies were awake and moving, they broke the beam and these breaks in the beam were counted and recorded.

To study the flies’ biological clocks, the researchers attached the protein luciferase – an enzyme that emits light – to one of the proteins that forms part of the biological clock. Levels of the protein rise and fall during the night and day, and the glowing protein provided a way of tracing the flies’ internal clock.

"This lets us see the brain glowing brighter at night and less during the day, and that’s the biological clock shown as a glowing brain. It’s beautiful to be able to study first hand in the same organism the molecular working of the clock and the corresponding behaviours," Dr Crowther said.

They found that healthy flies were active during the day and slept at night, whereas those with Alzheimer’s sleep and wake randomly. Crucially, however, the diurnal patterns of the luciferase-tagged protein were the same in both healthy and diseased flies, showing that the biological clock still ticks in flies with Alzheimer’s.

"Until now, the prevailing view was that Alzheimer’s destroyed the biological clock," said Crowther.

"What we have shown in flies with Alzheimer’s is that the clock is still ticking but is being ignored by other parts of the brain and body that govern behaviour. If we can understand this, it could help us develop new therapies to tackle sleep disturbances in people with Alzheimer’s."

Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, who helped to fund the study, said: “Understanding the biology behind distressing symptoms like sleep problems is important to guide the development of new approaches to manage or treat them. This study sheds more light on the how features of Alzheimer’s can affect the molecular mechanisms controlling sleep-wake cycles in flies.

"We hope these results can guide further studies in people to ensure that progress is made for the half a million people in the UK with the disease."

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breakingnews:

Nun, 84, is sentenced to nearly 3 years in prison for nuclear protest

Associated Press: An 84-year-old nun has been sentenced to nearly three years in prison for breaking into and defacing a storage bunker holding bomb-grade uranium in a peace demonstration at a Tennessee weapons plant.
Megan Rice was sentenced Tuesday along with activists Greg Boertje-Obed and Michael Walli. The men were sentenced to more than five years in prison.

Photo: Greg Boertje-Obed, left, Sister Megan Rice and Michael Walli after a hearing in Knoxville, Tenn. / Reuters