Une microsphère est une petite particule de géométrie sphérique avec un diamètre de l'ordre du micromètre (entre 1 μm et 1 mm). Les microsphères sont parfois appelées « microparticules » ou microperles.Les microsphères sont obtenues à partir de différents matériaux naturels ou synthétiques. Des microsphères de verre, de polymères (microbilles de plastique notamment) ou de céramique sont disponibles dans le commerce.

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  • Une microsphère est une petite particule de géométrie sphérique avec un diamètre de l'ordre du micromètre (entre 1 μm et 1 mm). Les microsphères sont parfois appelées « microparticules » ou microperles.Les microsphères sont obtenues à partir de différents matériaux naturels ou synthétiques. Des microsphères de verre, de polymères (microbilles de plastique notamment) ou de céramique sont disponibles dans le commerce. Elles peuvent être pleines ou creuses selon l'application à laquelle on les destine, avec donc des densités très différentes. Les microsphères creuses sont souvent utilisées pour alléger un matériau, tandis que les microsphères pleines ont de très nombreuses applications selon le matériau qui les compose et leur taille.
  • Microspheres are small spherical particles, with diameters in the micrometer range (typically 1 μm to 1000 μm (1 mm)). Microspheres are sometimes referred to as microparticles.Microspheres can be manufactured from various natural and synthetic materials. Glass microspheres, polymer microspheres and ceramic microspheres are commercially available. Solid and hollow microspheres vary widely in density and, therefore, are used for different applications. Hollow microspheres are typically used as additives to lower the density of a material. Solid microspheres have numerous applications depending on what material they are constructed of and what size they are.Polyethylene, polystyrene and expandable microspheres are the most common types of polymer microspheres. Polystyrene microspheres are typically used in biomedical applications due to their ability to facilitate procedures such as cell sorting and immunio precipitation. Proteins and ligands adsorb onto polystyrene readily and permanently, which makes polystyrene microspheres suitable for medical research and biological laboratory experiments.Polyethylene microspheres are commonly used as a permanent or temporary filler. Lower melting temperature enables polyethylene microspheres to create porous structures in ceramics and other materials. High sphericity of polyethylene microspheres, as well as availability of colored and fluorescent microspheres, makes them highly desirable for flow visualization and fluid flow analysis, microscopy techniques, health sciences, process troubleshooting and numerous research applications. Charged polyethylene microspheres are also used in electronic paper digital displays.Expandable microspheres are polymer microspheres that are used as a blowing agent in e.g. puff ink, automotive underbody coatings and injection molding of thermoplastics. They can also be used as a lightweight filler in e.g. cultured marble, waterborne paints and crack fillers/joint compound. Expandable polymer microspheres can expand to more than 50 times their original size when heat is applied to them. The exterior wall of each sphere is a thermoplastic shell that encapsulates a low boiling point hydrocarbon. When heated, this outside shell softens and expands as the hydrocarbon exerts a pressure on the internal shell wall.Glass microspheres are primarily used as a filler and volumizer for weight reduction, retro-reflector for highway safety, additive for cosmetics and adhesives, with limited applications in medical technology.Microspheres made from highly transparent glass can perform as very high quality optical microcavities or optical microresonators. Ceramic microspheres are used primarily as grinding media.Hollow microspheres loaded with drug in their outer polymer shell were prepared by a novel emulsion solvent diffusion method and spray drying technique. Microspheres vary widely in quality, sphericity, uniformity, particle size and particle size distribution. The appropriate microsphere needs to be chosen for each unique application.
  • Bu madde büyük oranda, bazı bilimadamları tarafından yaşamın kökeni için anahtar bir aşama olarak görülen küçük küresel birimler olarak mikro kürelere veya protein proto hücrelere atıfta bulunmaktadır. Mikro küre terimi çok çeşitli alanlarda; maddeler bilgisi ve eczacılık gibi, kullanılmaktadır.1953'te, Stanley Lloyd Miller ve Harold Urey yaşam oluşmadan önce Dünya'da varolan şartları taklit etmek üzere laboratuvar ortamında inorganik öncü bileşiklerden birçok basit biyomolekülün yapılabileceğini gösterdi. Özel olarak elde edilen amino asitlerle ilgilenildi çünkü amino asitler proteinlerin yapıtaşlarıdır.1957'de, Sidney Fox aşırı olmayan ısıya tabi tutulan kuru amino asit karışımlarının polimerize olmaya özendirilebileceğini gösterdi. Elde edilen polipeptitler veya proteinoitler sıcak suda çözündürülüp kurumaya bırakıldıktan sonra 2 μm çapında—küçük küresel yapılar:mikro küreler oluşturdu. Uygun koşullar altında mikro küreler kendi yüzeylerinde yeni küreler oluşturmaktadır.
  • Em bioquímica, microsferas são pequenas bolsas delimitadas por membranas constituidas de moléculas protéicas.Ela foi descoberta em 1957, quando Sidney Fox aqueceu aminoácidos em uma superfície seca e , logo após, adicionou água levemente salgada.Elas podem aumentar de tamanho e se fragmentar em glóbulos menores.Essas bolsas, junto com os coacervados de Oparin, não são seres vivos e estão longe de desvendar os mistérios da origem da vida, mas são um grande passo dessa longa caminhada. Entretanto, eles mostram que moléculas precursoras da vida podem ter originado aglomerados isolados do ambiente e capazes de se manter organizados por algum tempo.Fontes: Biologia: biologia das células (parte 1)[Moderna Plus]
  • Mikrosphären, Protein-Protozellen oder behüllte Koazervate sind kleine, kugelförmige Molekülaggregate, die von einigen Wissenschaftlern als bedeutender Entwicklungsschritt während der Entwicklung des Lebens angesehen werden. 1953 demonstrierten Stanley Miller und Harold Clayton Urey im sogenannten Miller-Urey-Experiment, dass viele einfache Biomoleküle unter Laborbedingungen, die der Erde vor der Evolution des Lebens nachempfunden waren, spontan aus Vorstufen dieser Verbindungen (Biomoleküle) entstehen konnten. Von besonderem Interesse war die beträchtliche Ausbeute an Aminosäuren, da Aminosäuren die Grundsteine der Proteine sind. 1957 demonstrierte Sidney W. Fox, dass Aminosäuren bei gleichzeitiger Erwärmung dazu gebracht werden konnten, sich miteinander zu verbinden, also zu polymerisieren. Diese Polypeptide formten kugelförmige Hohlkörper. Es bildeten sich durch Selbstaggregation membranartige Hüllen um die Koazervate, und es entstanden Mikrosphären (Koazervate mit Hülle). Unter geeigneten Bedingungen bilden Mikrosphären neue Mikrosphären auf ihrer Oberfläche. Obwohl sie in ihrem Erscheinungsbild Zellen ähneln, sind sie keine lebenden Systeme, da sie sich nicht exakt reproduzieren können und kein genetisches Material enthalten und weitergeben können. Jedoch waren sie wahrscheinlich für die Entwicklung des Lebens insofern bedeutend, als sie ein membranumschlossenes Volumen zur Verfügung stellten, das sich evtl. über Hyperzyklen in Vorformen einer Zelle entwickeln konnte.
  • 마이크로스피어(microsphere)는 크기가 1.4~2.5μm인 구형의 아미노산 중합체(重合體, polymer)로, 지구상에 생명체가 생겨나는데 중요한 역할을 했을 것으로 여겨지는 물질이다.1959년 폭스(Sidney Fox), 하라다(K. Harada), 켄드릭(J. Kendrick)은 실험실에서 아미노산을 이용해 마이크로스피어를 합성하고, 이 물질에서부터 생명체를 구성하는 기본 단위인 세포가 생겨났을 것이라는 프로테노이드설(proteinoid theory)을 주장하였다.
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  • Une microsphère est une petite particule de géométrie sphérique avec un diamètre de l'ordre du micromètre (entre 1 μm et 1 mm). Les microsphères sont parfois appelées « microparticules » ou microperles.Les microsphères sont obtenues à partir de différents matériaux naturels ou synthétiques. Des microsphères de verre, de polymères (microbilles de plastique notamment) ou de céramique sont disponibles dans le commerce.
  • 마이크로스피어(microsphere)는 크기가 1.4~2.5μm인 구형의 아미노산 중합체(重合體, polymer)로, 지구상에 생명체가 생겨나는데 중요한 역할을 했을 것으로 여겨지는 물질이다.1959년 폭스(Sidney Fox), 하라다(K. Harada), 켄드릭(J. Kendrick)은 실험실에서 아미노산을 이용해 마이크로스피어를 합성하고, 이 물질에서부터 생명체를 구성하는 기본 단위인 세포가 생겨났을 것이라는 프로테노이드설(proteinoid theory)을 주장하였다.
  • Mikrosphären, Protein-Protozellen oder behüllte Koazervate sind kleine, kugelförmige Molekülaggregate, die von einigen Wissenschaftlern als bedeutender Entwicklungsschritt während der Entwicklung des Lebens angesehen werden.
  • Em bioquímica, microsferas são pequenas bolsas delimitadas por membranas constituidas de moléculas protéicas.Ela foi descoberta em 1957, quando Sidney Fox aqueceu aminoácidos em uma superfície seca e , logo após, adicionou água levemente salgada.Elas podem aumentar de tamanho e se fragmentar em glóbulos menores.Essas bolsas, junto com os coacervados de Oparin, não são seres vivos e estão longe de desvendar os mistérios da origem da vida, mas são um grande passo dessa longa caminhada.
  • Microspheres are small spherical particles, with diameters in the micrometer range (typically 1 μm to 1000 μm (1 mm)). Microspheres are sometimes referred to as microparticles.Microspheres can be manufactured from various natural and synthetic materials. Glass microspheres, polymer microspheres and ceramic microspheres are commercially available. Solid and hollow microspheres vary widely in density and, therefore, are used for different applications.
  • Bu madde büyük oranda, bazı bilimadamları tarafından yaşamın kökeni için anahtar bir aşama olarak görülen küçük küresel birimler olarak mikro kürelere veya protein proto hücrelere atıfta bulunmaktadır.
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  • Microsphère
  • Microesfera
  • Microsphere
  • Mikro küre
  • Mikrosphäre
  • 마이크로스피어
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