21st-century inventions

A blockchain is a distributed ledger with growing lists of records (blocks) that are securely linked together via cryptographic hashes. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data (generally represented as a Merkle tree, where data nodes are represented by leaves). Since each block contains information about the previous block, they effectively form a chain (viz. linked list data structure), with each additional block linking to the ones before it. Consequently, blockchain transactions are resistant to alteration because, once recorded, the

thumb|An episode of a podcast playing on a smartphone A podcast is a program episode made available in digital format for download over the Internet. Podcasts are primarily an audio medium, which is reflected in the term itself, a portmanteau of "iPod" and "broadcast" coined in 2004. The term used to refer to an episodic series of digital audio files that users can download to a personal device or stream to listen to at a time of their choosing. In the mid-2020s, however, video podcasts, either as primary content included in the feed, or as an external supplement to audio, have been popularize

Blu-ray (Blu-ray Disc or BD) is a digital optical disc data storage format designed to supersede the DVD format. It was invented and developed in 2005 and released worldwide on June 20, 2006, capable of storing several hours of high-definition video (HDTV 720p and 1080p). The main application of Blu-ray is as a medium for video material such as feature films and for the physical distribution of video games for the PlayStation 3, PlayStation 4, PlayStation 5, Xbox One, and Xbox Series X. The name refers to the blue laser used to read the disc, which allows information to be stored at a greater

Internet-like structure connecting everyday physical objects

device usually used to quit or be an alternative to tobacco

Graphene () is a variety of the element carbon which occurs naturally in small amounts. In graphene, the carbon forms a sheet of interlocked atoms as hexagons one carbon atom thick. The result resembles the face of a honeycomb. When many hundreds of graphene layers build up, they are called graphite.

transdermal patch applied to prevent pregnancy

type of endoscopy

novel type of vaccine

thumb|Cronut cross-section The cronut (the name represents a portmanteau of croissant and doughnut) is a pastry developed and trademarked in New York in 2013 by the French pastry-chef Dominique Ansel. Resembling a doughnut, it is made from croissant-like dough filled with flavored cream and fried in grapeseed oil.

non-lethal bomb used to seal tunnels

Vitrimers are a class of plastics, which are derived from thermosetting polymers (thermosets) and are very similar to them. Vitrimers consist of molecular, covalent networks, which can change their topology by thermally activated bond-exchange reactions. At high temperatures, they can flow like viscoelastic liquids; at low temperatures, the bond-exchange reactions are immeasurably slow (frozen), and the Vitrimers behave like classical thermosets at this point. Vitrimers are strong glass formers. Their behavior opens new possibilities in the application of thermosets, such as a self-healing mat