SANTé/MEDECINE - Espoir : Des bio-implants immunologiques contre le cancer

Des petites billes pourraient augmenter l’action des cellules immunitaires chargées de combattre le cancer.

Des billes de la taille d’une tête d’épingle, mises au point par des bio-ingénieurs de l'Université Rice, aux Etats-Unis, contiennent des cellules conçues pour produire d’importantes doses d’interleukine-2 (IL-2), une protéine activatrice des globules blancs chargés de combattre le cancer.

Une augmentation de l’action des cellules immunitaires tout en réduisant les effets secondaires

Implantées à proximité d’une tumeur, ces billes délivrent l’IL-2 au plus proche, augmentant l’action des cellules immunitaires tout en réduisant les effets secondaires. Chez la souris, le traitement s’est révélé redoutablement efficace, éradiquant en quelques jours les tumeurs dont souffraient les rongeurs. Des essais sur l’humain doivent commencer à l’automne.

SciencesAvenir

ASTRONOMY - Ship Tracks over the Pacific Ocean

 2022 June 8

Ship Tracks over the Pacific Ocean
Image Credit: NASA, Terra, MODIS; Text: Raymond Shaw (MTU)

Explanation: What are those unusual streaks? Some images of planet Earth show clear bright streaks that follow the paths of ships. Known as ship tracks, these low and narrow bands are caused by the ship's engine exhaust. Water vapor condenses around small bits of exhaust known as aerosols, which soon grow into floating water drops that efficiently reflect sunlight. Ship tracks were first discovered in 1965 in Earth images taken by NASA's TIROS satellites. Multiple ship tracks are visible across the featured image that was captured in 2009 over the Pacific Ocean by the MODIS instrument on NASA's Terra satellite. Inspired by ship-tracks, some scientists have suggested deploying a network of floating buoys in the worlds' oceans that spray salt-aerosol containing sea-water into the air so that, with the help of the wind, streams of sunlight-reflecting clouds would also form. Why do this? These human-made clouds could reflect so much sunlight they might help fight global warming.

ASTRONOMY - NGC 6188: Dragons of Ara

 2022 June 7

NGC 6188: Dragons of Ara
Image Credit & Copyright: Shaun Robertson

Explanation: Do dragons fight on the altar of the sky? Although it might appear that way, these dragons are illusions made of thin gas and dust. The emission nebula NGC 6188, home to the glowing clouds, is found about 4,000 light years away near the edge of a large molecular cloud unseen at visible wavelengths, in the southern constellation Ara (the Altar). Massive, young stars of the embedded Ara OB1 association were formed in that region only a few million years ago, sculpting the dark shapes and powering the nebular glow with stellar winds and intense ultraviolet radiation. The recent star formation itself was likely triggered by winds and supernova explosions, from previous generations of massive stars, that swept up and compressed the molecular gas. Joining NGC 6188 on this cosmic canvas, visible toward the lower right, is rare emission nebula NGC 6164, also created by one of the region's massive O-type stars. Similar in appearance to many planetary nebulae, NGC 6164's striking, symmetric gaseous shroud and faint halo surround its bright central star near the bottom edge. This impressively wide field of view spans over 2 degrees (four full Moons), corresponding to over 150 light years at the estimated distance of NGC 6188.

MERVEILLEUX MONDE SOUS-MARIN - Jardin Corallien

 © Alexis Rosenfeld

ASTRONOMY - Milky Way Galaxy Doomed: Collision with Andromeda Pending

 2022 June 6

Milky Way Galaxy Doomed: Collision with Andromeda Pending
Image Credit: NASA, ESA, Z. Levay and R. van der Marel (STScI); T. Hallas; and A. Mellinger

Explanation: Will our Milky Way Galaxy collide one day with its larger neighbor, the Andromeda Galaxy? Most likely, yes. Careful plotting of slight displacements of M31's stars relative to background galaxies on recent Hubble Space Telescope images indicate that the center of M31 could be on a direct collision course with the center of our home galaxy. Still, the errors in sideways velocity appear sufficiently large to admit a good chance that the central parts of the two galaxies will miss, slightly, but will become close enough for their outer halos to become gravitationally entangled. Once that happens, the two galaxies will become bound, dance around, and eventually merge to become one large elliptical galaxy -- over the next few billion years. Pictured here is a combination of images depicting the sky of a world (Earth?) in the distant future when the outer parts of each galaxy begin to collide. The exact future of our Milky Way and the entire surrounding Local Group of Galaxies is likely to remain an active topic of research for years to come.

PHOTOGRAPHIE - Milky Way fascination

Milky Way fascination

Nuit d'observation au Dobson sous un superbe ciel depuis le centre de la France

Technique : APN Sony Nex5, objectif samyang 14mm (1er plan) et canon 50 f1.8 (voie lactée) staradventurer skywatcher; 70x10s iso 1600 | Date : 01.10.2019

Kamel

ASTRONOMY - Two Black Holes Dancing in 3C 75

 2022 June 5

Two Black Holes Dancing in 3C 75
Image Credit: X-Ray: NASA/CXC/D. Hudson, T. Reiprich et al. (AIfA); Radio: NRAO/VLA/ NRL

Explanation: What's happening at the center of active galaxy 3C 75? The two bright sources at the center of this composite x-ray (blue)/ radio (pink) image are co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years. At the cores of two merging galaxies in the Abell 400 galaxy cluster they are some 300 million light-years away. Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part because the jets' consistent swept back appearance is most likely due to their common motion as they speed through the hot cluster gas at about 1200 kilometers per second. Such spectacular cosmic mergers are thought to be common in crowded galaxy cluster environments in the distant universe. In their final stages, the mergers are expected to be intense sources of gravitational waves.

ASTRONOMY - Tau Herculids from Space

 2022 June 4

Tau Herculids from Space
Image Credit & Copyright: Zhuoxiao Wang, Yangwang-1 Space Telescope, Origin.Space

Explanation: On May 31 tens of parallel meteor streaks were recorded in this 8 degree wide field of view of planet Earth's limb from space. The image is one of a series of 5 minute long observations by the orbiting Yangwang-1 space telescope. It was captured at 03:43 UT, near the peak of the Tau Herculid meteor shower. As predicted, the meteor shower was an active one this year, caused as Earth swept through a relatively dense stream of debris from disintegrating Comet 73P/Schwassmann-Wachmann 3, but was lacking bright meteors. Nearly all of the Tau Herculid meteors in the Yangwang-1 image are too faint to be detected by groundbased instruments. But on that date patient earthbound skywatchers under clear skies still enjoyed a memorable showing of the Tau Herculids.

ASTRONOMY - A 10,000 Kilometer Galactic Bridge

 2022 June 3

A 10,000 Kilometer Galactic Bridge
Image Credit & Copyright: Maxime Oudoux, Jean-Francois GELY

Explanation: With this creative astro-collaboration you can follow the plane of our Milky Way Galaxy as it bridges northern and southern hemisphere skies. To construct the expansive composite nightscape, skies over Observatorio El Sauce in Chile (top) were imaged on the same date but 6 hours later than the skies over the Saint-Veran observatory in the French Alps. The 6 hour time-lag allowed Earth's rotation to align the Milky Way above domes at the two sites. All exposures were made with similar cameras and lenses mounted on simple tripods. A faint greenish airglow is visible in the dark Chilean sky that also features the Large and Small Magellanic Clouds near the observatory dome. In the French Alps light pollution is apparent, but the distant Andromeda Galaxy can still be spotted near the horizon in the northern night. On planet Earth the two observatories are separated by about 10,000 kilometers.

ASTRONOMY - Lunar Occultation of Venus

 2022 June 2

Lunar Occultation of Venus
Image Credit & Copyright: Quentin Gineys

Explanation: On May 27 Venus rose as the morning star, near the waning crescent Moon in a predawn sky already full of planets. It was close on the sky to the Moon's crescent and a conjunction of the second an third brightest celestial beacons were enjoyed by skygazers around the world. But seen from locations along a track through southeast Asia and the Indian Ocean the Moon actually passed in front of Venus in a lunar occultation. In this animated gif the 75 percent illuminated disk of Venus approaches and just begins to disappear behind the sunlit southwestern lunar limb. The telescopic frames used to construct it were captured from Reunion Island in the Indian Ocean around 4:50am local time, with the Moon and Venus very close to the eastern horizon. At the time Venus was over 180 million kilometers from Reunion Island, compared to a lunar distance of a mere 400 thousand kilometers or so. About 50 minutes later Venus emerged from behind the Moon.