There is provided a method of manufacturing silica microspheres includes the steps of mixing acid and water to form a mixture; adding a silicon alkoxide to the mixture so as to precipitate microspheres; allowing the microspheres to settle into a sediment and removing a supernatant liquid; and immersing the microspheres in acid.

One variation of a diamond composition includes carbon: including a first amount of carbon-13 isotopes and a second amount of carbon-12 isotopes; and sourced from a hydrocarbon mixture including hydrocarbons and formed via methanation of a carbon dioxide mixture. The carbon dioxide mixture: sourced from a sample of air including carbon dioxide and impurities; conveyed through a separation unit configured to remove impurities; including carbon dioxide and impurities; conveyed through a distillation column configured to regulate amounts of carbon-13 isotopes and carbon-12 isotopes; and exhibiting a target ratio of carbon-13 isotopes to carbon-12 isotopes at an outlet of the distillation column. The diamond composition: formed via chemical vapor deposition; and exhibiting an isotopic signature defining a final ratio of the first amount of carbon-13 isotopes to the second amount of carbon-12 isotopes within a first target range corresponding to the target ratio exhibited by the carbon dioxide mixture.

One variation of a diamond composition includes carbon: including a first amount of carbon-13 isotopes and a second amount of carbon-12 isotopes; and sourced from a hydrocarbon mixture including hydrocarbons and formed via methanation of a carbon dioxide mixture. The carbon dioxide mixture: sourced from a sample of air including carbon dioxide and impurities; conveyed through a separation unit configured to remove impurities; including carbon dioxide and impurities; conveyed through a distillation column configured to regulate amounts of carbon-13 isotopes and carbon-12 isotopes; and exhibiting a target ratio of carbon-13 isotopes to carbon-12 isotopes at an outlet of the distillation column. The diamond composition: formed via chemical vapor deposition; and exhibiting an isotopic signature defining a final ratio of the first amount of carbon-13 isotopes to the second amount of carbon-12 isotopes within a first target range corresponding to the target ratio exhibited by the carbon dioxide mixture.

According to an example aspect of the present invention, there is provided a method for preparing a gaseous isotope reference, the method comprising: providing a solid or liquid carbon-containing material exhibiting a carbon isotope ratio; providing oxygen gas or a gas mixture comprising oxygen gas, wherein said gas or gas mixture exhibits an oxygen isotope ratio; determining said carbon isotope ratio in the solid carbon-containing material and/or determining said oxygen isotope ratio in the oxygen gas or the gas mixture comprising oxygen; bringing the solid carbon-containing material in contact with the oxygen gas or the gas mixture comprising oxygen gas, in a high temperature in order to oxidize at least a part of the solid carbon-containing material to carbon dioxide to obtain the gaseous carbon and/or oxygen isotope reference in the form of carbon dioxide.

Method and Apparatus for separating at least one CO isotope compound, especially isotope compound 13C16O, from natural CO, comprising: a rectification column system (110) comprising a plurality of rectification sections (112,114,116,118,120) arranged adjacent to one another in a chain-like manner, including an upper rectification section (112) and a plurality of lower rectification sections (114,116,118,120), each rectification section comprising a heating means (112a,114a,116a,118a,120a) to maintain evaporation of liquid present therein, provided that the heating means (112a) of the at least one of the plurality of rectification sections (112) is provided to comprise a heat pump cycle (112b).

Method and Apparatus for separating at least one CO isotope compound, especially isotope compound 13C16O, from natural CO, comprising: a rectification column system (110) comprising a plurality of rectification sections (112,114,116,118,120) arranged adjacent to one another in a chain-like manner, including an upper rectification section (112) and a plurality of lower rectification sections (114,116,118,120), each rectification section comprising a heating means (112a,114a,116a,118a,120a) to maintain evaporation of liquid present therein, provided that the heating means (112a) of the at least one of the plurality of rectification sections (112) is provided to comprise a heat pump cycle (112b).

The present disclosure discloses a method for preparing a labelled plant and a method for preparing a labelled biochar. The method for preparing a labelled plant includes the following steps: preparing a box; placing a plant that is capable of photosynthesis in the box; preparing a labelled gas in the box, the labelled gas being an isotope-labelled carbon dioxide gas; and leaving the box standing for a preset period of time, during which the plant absorbs the labelled gas to obtain a labelled plant. In the present disclosure, the carbon element in the plant is labelled during the growth of the plant, and the concentration of .sup.13CO.sub.2 in the box is controlled by controlling the concentration of Na.sub.2.sup.13CO.sub.3, where .sup.13CO.sub.2 is prepared by chemical methods, which could improve the utilization rate of .sup.13C.

A sensor system is based on diamonds with a high density of NV centers. The description includes a) methods for producing the necessary diamonds of high NV center density, b) characteristics of such diamonds, c) sensing elements for utilizing the fluorescence radiation of such diamonds, d) sensing elements for utilizing the photocurrent of such diamonds, e) systems for evaluating these quantities, f) reduced noise systems for evaluating these systems, g) enclosures for using such systems in automatic placement equipment, g) methods for testing these systems, and h) a musical instrument as an example of an ultimate application of all these devices and methods.

Described are methods for preparing radionuclides, such as radionuclides having a high specific activity. The disclosed methods include irradiating target nuclide materials, in solution, with a neutron source. The radionuclides can be separated from the target nuclide material by providing a solid carbon nanostructured material, as a suspension of solids, proximal to the target nuclide material in solution and using the recoil to drive adsorption of the radionuclide onto the solid carbon nanostructured material to transfer the radionuclides from the liquid phase (in solution) to the solid phase (adsorbed to the suspended solid carbon nanostructured material). One or more surfactants can be incorporated into the solution to facilitate formation of a stable suspension of the solid carbon nanostructured material.

Disclosed herein are methods preparing a purified, carrier-free 68Ga solution. Tire present disclosure also provides systems for preparing a purified, carrier-free 68Ga solution. The present disclosure also provides compositions comprising the purified, carrier-free 68Ga solutions disclosed herein. Also provided are methods of administering compositions of the present disclosure to a patient in need thereof, for example, for imaging a disease or disorder, such as cancer.