Copper aspirinate use of copper aspirinate as a pigment in PVC and Polystyrene has also been investigated. Copper aspirinate Copper(II) aspirinate is an aspirin chelate of copper(II) cations (Cu). It is used to treat rheumatoid arthritis. Copper aspirinate can be prepared by several methods. In one route of preparation, an excess of acetylsalicylic acid is dissolved in aqueous sodium carbonate. Sodium hydroxide is not suitable for this purpose, because it will hydrolyse acetylsalicylic acid ("ASA") into salicylic acid and sodium acetate. The resulting solution is then filtered to remove any undissolved acetylsalicylic acid and is mixed with a solution containing Cu cations
Birch bark manuscript In Indian sculpture, a Birch bark manuscript is easily identified by the droop. A palm leaf manuscript is stiff. On July 26, 1951, during excavations in Novgorod, a Soviet expedition led by Artemiy Artsikhovsky found the first Russian birch bark writing in a layer dated to c. 1400. Since then, more than 1,000 similar documents were discovered in Staraya Russa, Smolensk, Torzhok, Pskov, Tver, Moscow, Ryazan, and Vologda, although Novgorod remains by far the most prolific source of them. In Ukraine, birch bark documents were found in Zvenyhorod, Volynia. In Belarus, several documents were unearthed in Vitebsk and Mstislavl. The