BIOMIMETISME - LA NATURE INSPIRE LA SCIENCE - Les feuilles autonettoyantes du lotus

Le lotus (Nelumbo spp) est une plante aquatique. Pourtant l'eau, ce n'est pas vraiment son truc, surtout sur ses feuilles. En effet, ces dernières sont superhydrophobes, c'est-à-dire que leur surface repousse l'eau, elle glisse littéralement sur les feuilles. Les propriétés superhydrophobes des feuilles de lotus sont dues à une rugosité nanométrique, des petites pointes de l'ordre du nanomètre. Lorsqu'une goutte d'eau tombe sur les petites pointes, elle n'y adhère pas et emporte avec elle les impuretés présentes sur la plante.

Cette propriété physique intéresse bon nombre de domaines et cela depuis sa découverte dans les années 70. Des tissus déperlants, des parois de douche autonettoyantes ou encore des revêtements utilisés en aéronautique sont basés sur la rugosité nanométrique.

© William Thielicke, Wikimedia Commons, CC by-sa 4.0 International, 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license

FuturaSciences

ASTRONOMY - The Butterfly Nebula from Hubble

 2022 November 21

The Butterfly Nebula from Hubble
Image Credit: NASA, ESA, Hubble; Processing: William Ostling

Explanation: Stars can make beautiful patterns as they age -- sometimes similar to flowers or insects. NGC 6302, the Butterfly Nebula, is a notable example. Though its gaseous wingspan covers over 3 light-years and its estimated surface temperature exceeds 200,000 degrees C, the aging central star of NGC 6302, the featured planetary nebula, has become exceptionally hot, shining brightly in visible and ultraviolet light but hidden from direct view by a dense torus of dust. This sharp close-up was recorded by the Hubble Space Telescope and is processed here to show off remarkable details of the complex planetary nebula, highlighting in particular light emitted by oxygen (shown as blue), hydrogen (green), and nitrogen (red). NGC 6302 lies about 3,500 light-years away in the arachnologically correct constellation of the Scorpion (Scorpius). Planetary nebulas evolve from outer atmospheres of stars like our Sun, but usually fade in about 20,000 years.

ASTRONOMY - Airglow Ripples over Tibet

 2022 November 20

Airglow Ripples over Tibet
Image Credit & Copyright: Jeff Dai

Explanation: Why would the sky look like a giant target? Airglow. Following a giant thunderstorm over Bangladesh in late April, giant circular ripples of glowing air appeared over Tibet, China, as pictured here. The unusual pattern is created by atmospheric gravity waves, waves of alternating air pressure that can grow with height as the air thins, in this case about 90-kilometers up. Unlike auroras powered by collisions with energetic charged particles and seen at high latitudes, airglow is due to chemiluminescence, the production of light in a chemical reaction. More typically seen near the horizon, airglow keeps the night sky from ever being completely dark.

MUSIC - Tchaikovsky - Waltz of the flowers (Daniel Barenboim - Berliner Philarmoniker)

"Waltz of the flowers"

ASTRONOMY - Artemis 1 Moonshot

 2022 November 19

Artemis 1 Moonshot
Image Credit & Copyright: John Kraus

Explanation: When the Artemis 1 mission's Orion spacecraft makes its November 21 powered flyby of the Moon, denizens of planet Earth will see the Moon in a waning crescent phase. The spacecraft will approach to within about 130 kilometers of the lunar surface on its way to a distant retrograde orbit some 70,000 kilometers beyond the Moon. But the Moon was at last quarter for the November 16 launch and near the horizon in the dark early hours after midnight. It's captured here in skies over Kennedy Space Center along with the SLS rocket engines and solid rocket boosters lofting the uncrewed Orion to space. Ragged fringes appearing along the bright edge of the sunlit lunar nearside are caused as pressure waves generated by the rocket's passage change the index of refraction along the camera's line of sight.

MARAVILHOSO MUNDO SUBMARINO - A luta de um surfista contra a onda

Um surfista luta contra a turbulência submarina criada pela 'onda mais pesada do mundo'

Teahupo'o

Ben Thouard

SAUDE/MEDECINA - Esperança : um exército contra o cancro

Um mês após uma experiência realizada com 16 doentes com tumores sólidos, a equipa de investigadores verificou que cinco dos participantes apresentaram doença estável, ou seja, os seus tumores deixaram de evoluir

Em janeiro de 2020, investigadores da Universidade de Cardiff, no País de Gales, apresentavam os resultados de uma investigação que acreditava no desenvolvimento de uma terapia universal para todos os tipos de cancros. Os investigadores testaram um novo método terapêutico com sucesso, conseguindo eliminar células associadas aos cancros de pulmão, pele, sangue, cólon, mama, ossos, próstata, ovários, rim, e cervical durante ensaios efetuados em laboratório. Na origem destes testes bem sucedidos, publicados na revista Nature Immunology, encontravam-se células T, que fazem parte do sistema imunitário dos seres humanos.

Agora, um nova ensaio clínico mostrou que a edição de genes CRISPR pode ser utilizada para alterar as células imunológicas com o objetivo de que elas reconheçam proteínas com mutações específicas dos tumores de um doente. Essas células podem ser libertadas com segurança no corpo para encontrarem e destruirem os seus alvos. “Estamos a tentar criar um exército com as próprias células T do doente”, disse, em declarações à Nature, Antoni Ribas, médico e investigador em cancro da Universidade da Califórnia, Los Angeles.

https://visao.sapo.pt/visaosaude/2022-11-17-como-os-cientistas-estao-a-tentar-criar-um-exercito-contra-o-cancro-com-as-celulas-t-do-proprio-doente/

ASTRONOMY - The Protostar within L1527

 2022 November 18

The Protostar within L1527
Image Credit: Science - NASA, ESA, CSA, STScI, NIRCam
Processing - Joseph DePasquale (STScI), Anton M. Koekemoer (STScI), Alyssa Pagan (STScI)

Explanation: The protostar within dark cloud L1527 is a mere 100,000 years old, still embedded in the cloud of gas and dust that feeds its growth. In this NIRCam image from the James Webb Space Telescope, the dark band at the neck of the infrared nebula is a thick disk that surrounds the young stellar object. Viewed nearly edge-on and a little larger than our Solar System, the disk ultimately supplies material to the protostar while hiding it from Webb's direct infrared view. The nebula itself is seen in stunning detail though. Illuminated by infrared light from the protostar, the hourglass-shaped nebula's cavities are created as material ejected in the star-forming process plows through the surrounding medium. As the protostar gains mass it will eventually become a full-fledged star, collapsing and igniting nuclear fusion in its core. A likely analog to our own Sun and Solar System in their early infancy, the protostar within dark cloud L1527 lies some 460 light-years distant in the Taurus star-forming region. Webb's NIRCam image spans about 0.3 light-years.

SANTé/MéDECINE - Tabagisme et cigarette électronique

Selon le baromètre 2017 de Santé publique, 76,3 % des ex-fumeurs qui vapotent ou qui ont vapoté quotidiennement pendant au moins un mois déclarent que l’e‑cigarette les a aidés à arrêter de fumer. Passer de la cigarette à la cigarette électronique pourrait donc permettre le sevrage nicotinique. Mais si ce sevrage est rendu possible, comment doit-il être opéré pour avoir toutes les chances de fonctionner ?

Pour mettre fin à la dépendance nicotinique, encore faut-il en comprendre le fonctionnement, puisqu’il s’agit d’une dépendance physique dont les symptômes de sevrage peuvent être sévères ! Une fois consommée, la nicotine se fixe sur certains récepteurs du cerveau et provoque :

-une multiplication des récepteurs ;

-la libération de substances chimiques naturelles qui rend calme et alerte ;

-une sensation de bien-être ;

-un semblant de regain d’énergie.

Plus les récepteurs sont nombreux, plus le cerveau a tendance à réclamer de la nicotine, jusqu’à atteindre un niveau de besoin moyen au bout de quelques mois. L’utilisation de la cigarette électronique permet un calcul précis de la dose de nicotine ingérée. C’est en cela qu’elle est intéressante pour les fumeurs qui souhaitent se sevrer à l’aide d’outils qui sont hors du système de santé.

C’est la baisse progressive du taux de nicotine consommé quotidiennement qui permet la réussite d’un sevrage nicotinique. Et cette baisse progressive est assez simple à opérer à l’aide d’une cigarette électronique.

Lire plus sur :

https://www.futura-sciences.com/sante/questions-reponses/cigarette-electronique-cigarette-electronique-nicotine-sevrage-il-possible-17650/

ASTRONOMY - Planet Earth from Orion

 2022 November 17

Planet Earth from Orion
Image Credit: NASA, Artemis 1

Explanation: A Space Launch System rocket left planet Earth on Wednesday, November 16 at 1:47am EST carrying the Orion spacecraft on the Artemis 1 mission, the first integrated test of NASA’s deep space exploration systems. Over an hour after liftoff from Kennedy Space Center's historic Launch Complex 39B, one of Orion's external video cameras captured this view of its new perspective from space. In the foreground are Orion's Orbital Maneuvering System engine and auxillary engines, at the bottom of the European Service Module. Beyond one of the module's 7-meter long extended solar array wings lies the spacecraft's beautiful home world. The Artemis 1 mission will last almost four weeks, testing capabilities to enable human exploration of the Moon and Mars. The uncrewed Orion spacecraft is expected to fly by the Moon on November 21, performing a close approach to the lunar surface on its way to a retrograde orbit 70,000 kilometers beyond the Moon.