Encyclopedia
Silver nanoparticles embedded in an amorphous polystyrene matrix. The nanomaterial has been produced by thermal decomposition of silver dodecylthiolate in molten polystyrene.
09 Nov 2023
Carrageenan is a natural polysaccharide extracted from red seaweed, commonly used as a food additive for its gelling, thickening, and stabilizing properties. It is widely found in various processed foods, including dairy products, plant-based milk alternatives, sauces, and desserts. Carrageenan enhances texture and consistency, making products creamier and more appealing. However, its safety has been debated, with some studies suggesting potential gastrointestinal inflammation when consumed in large quantities. Despite these concerns, carrageenan remains approved by food safety authorities in many countries, provided it is used within regulated limits.
23 Aug 2024
Scanning electron microscopy (SEM) micrograph of microporous palladium produced by thermal decomposition of palladium-dodecylthiolate.
20 Nov 2023
When viewed under a microscope, a meteorite reveals a fascinating microcosm of the cosmos, characterized by a mix of minerals and textures that tell a story of its journey through space. The most striking features are the chondrules—spherical grains formed in the early solar system, often composed of silicate minerals like olivine and pyroxene. These chondrules are set within a fine-grained matrix that may include metallic iron-nickel and sulfide minerals.
In some meteorites, especially iron meteorites, the Widmanstätten pattern can be observed, displaying a distinctive interlocking crystal structure of iron-nickel alloys, formed over millions of years of slow cooling in space. The overall composition, ranging from crystalline to amorphous regions, along with occasional inclusions of tiny diamonds or other exotic minerals, provides a window into the early solar system's processes and the formation of planets.
09 Aug 2024
This negatively-stained transmission electron micrograph (TEM) revealed the presence of numerous negative-sense, single-stranded RNA ((-) ssRNA) Flanders virus virions. Note the bullet-like shape of these virions, which are very similar to other Rhabdoviruses.
Public Health Image Library
17 Jan 2024
Aphanothece (a-fan-owe-theek-ee), blue green alga in which many coccoid or cylindrical cells share a common mucus sheath. Differential interference contrast.
Michele Bahr and David Patterson, micro*scope
25 Jul 2024
Scanning Electron Microscopy (SEM) micrograph of graphite nanoplatelets (GNP) prepared by sonication of expanded graphite, which is obtained by thermally treatment of graphite bisulfate[1].
15 Nov 2023
Transmission electron microscopy (TEM) micrograph of gold nanoparticles dispersed in PVP.
04 Dec 2023
Transmission electron microscopy (TEM) micrograph of MW-CNT bundles.
04 Dec 2023
Iron(II) sulphide (FeS) is a chalcogenide, which can be chemically synthesized by thermal decomposition of iron(II) n-alkyl-thiolates, like for example the iron(II) docecyl-thiolate (Fe(SC12H25)2), at a temperature of ca. 200°C. This compound can be obtained in form of acicular nanostructures by in situ decomposition of iron(II) dodecyl-thiolate dissolved in a non-polar amorphous polymer, like polystyrene. During the thiolate thermal decomposition process in air, FeS is partially converted to iron oxide (hematite α-Fe2O3)[1]. The obtained polymeric nanocomposite shows magnetic properties and is perfectly transparent (absence of the light-scattering phenomenon). Iron(II) thiolate has been produced by precipitation from an alcoholic solution (ethanol) of iron(II) chloride (FeCl2) and dodecanethiol (C12H25SH). The polymeric solution of iron(II) thiolate was obtained by the solution casting technology (i.e., both polymer and thiolate are dissolved in an adequate solvent like chloroform and then the solvent is allowed to evaporate).
08 Jan 2024
Scanning electron microscopy (SEM) micrograph of graphite nanoplatelets (GNP) [1].
15 Nov 2023
Transmission electron microscopy (TEM) micrograph of graphite oxide (GO) prepared by applying the Hummers' method to graphite nanoplatelets (GNP).
04 Dec 2023
Transmission electron microscopy (TEM) micrograph of a MW-CNT bundle.
04 Dec 2023
When strongly exothermic chemical reactions are performed in mass, they undergo an auto-acceleration process because of the temperature increase that usually accompanies these reactions. The auto-acceleration reactions can be kinetically controlled by dividing the reactive mass in several small portions, separated each-other by thermally insulating physical walls (e.g., ceramic walls) capable to limit the heat exchange phenomenon between adjacent cells. In this conditions, the reaction takes place at an almost constant temperature close to room-temperature. In order to stabilize the reactive mixture by using this principle, a micro-porous solid (also of natural origin, like diatomite or sawdust) can be used. Such potentiality of diatomite was exploited for the first time by Alfred Bernhard Nobel in the 1867 for the stabilization of nitroglycerine. Indeed, dynamite was simply nitroglycerin stabilized by diatomite. Diatomite is particularly effective for such a kind of application since it contains pseudo-cylindrical pores organized in a close-packed manner, which allows the highest pore density in the material. In addition diatomite is made of hydrated amorphous silica (opal), which is a very good thermally insulating material.
15 Dec 2023
Transmission electron microscopy (TEM) micrograph of dendritic structures generated by magnetite nano-particles embedded in polyvinylpyrrolidone (PVP) [1].
30 Nov 2023
‘Graphitic oxide’ (GO) was prepared by William S. Hummers in the 1958 by oxidizing graphite flakes with a strong oxidizing mixture made of potassium permanganate (KMnO4) and sodium nitrate (NaNO3) dissolved in sulfuric acid (H2SO4). Actually, the oxidizing agent is the in situ generated permanganic anidride (Mn2O7). This chemical reaction involves only a partial conversion of the graphite flakes to graphite oxide (indeed, the reaction yield is ca. 60%) and leads to a C/O ratio ranging between 1 to 2.1-2.9. However, a 100% conversion degree can be obtained by applying the same Hummers’ method to a graphite nanoplatelets (GNPs) powder. This reaction leads to a product known as ‘graphene oxide’, which is a much more oxidized and therefore water-soluble product compared to graphitic oxide. Graphene oxide can be thermally and chemically reduced to produce products very close to single-layer graphene. In particular, thermally-reduced graphene oxide (TRG) and chemically reduced graphene oxide represent a type of graphene containing a certain amount of structural defects like residual oxygen-containing groups (especially epoxies) and point defects.
13 Dec 2023
Graphite intercalated by sulphuric acid after the thermal expansion process.
07 Nov 2023
Transmission electron microscopy (TEM) micrograph of graphite oxide produced by the Hummer's method.
20 Nov 2023
A chemical substance uniformly distributed throughout a continuous dispersing medium in form of separate molecules, ions or atoms constitutes a homogeneous system. Nanostructures are miniaturized solid phases of molecular size that resemble homogeneous systems, indeed they are perfectly clear and transparent. However, nanostructures are visible in the electron microscope (TEM) and are capable to scatter visible light just like the heterogeneous systems. Therefore, nanostructures have been classified as nano-heterogeneous systems, since their heterogeneous nature can be disclosed only on an extremely small size scale.
20 Nov 2023
Diabetes is a chronic condition characterized by persistently elevated levels of blood sugar. It is primarily categorized into two main types: Type 1 diabetes and Type 2 diabetes. Additionally, there are other types such as gestational diabetes and idiopathic diabetes.
Type 1 diabetes typically results from insufficient production of insulin, which is an autoimmune disease where the immune system mistakenly attacks the beta cells that produce insulin in the pancreas. This leads to the inability of the body to produce adequate insulin to convert blood sugar into energy, necessitating insulin injections to maintain blood sugar levels.
Type 2 diabetes, on the other hand, is often associated with overweight, lack of physical activity, and genetic factors. In this scenario, body cells become resistant to insulin, leading to elevated blood sugar levels. Initially, management may involve dietary changes and increased physical activity, but in some cases, oral medications or insulin injections may be required.
Diabetes can lead to various complications including cardiovascular diseases, kidney diseases, eye problems, neuropathy, and others. Therefore, it's crucial for individuals with diabetes to manage the condition by controlling blood sugar levels, adopting a healthy lifestyle, and receiving regular medical care to minimize the risk of complications.
24 Jul 2024
