Abstract: Provided is a display apparatus that the image display quality does not deteriorate even if the screen size is increased. The display apparatus includes a display; a plurality of light sources; and a controller controlling the light sources. When a character information is present in a display region of the display, the controller controls a luminance of at least a region comprising the character information to be higher than a predetermined luminance.

Abstract: A document reading apparatus has a slit along one side of a document support platen of a glass plate to insert one part of an opened book as a document to be read. An insertion pocket forming a recessed space contiguous with the slit and inclined diagonally is provided in the apparatus. A lid is operable between open and closed positions exposing and covering the slit. In the open position, one part of a book can be inserted into the slit with a page in the other part of the book being in intimate contact with the platen, while in the closed position, a sheet as a document can be placed at a proper position on the platen by contacting one side of the sheet to a rim of the lid. This apparatus prevents a problem of image deformation and black image in print output when reading the book.

Abstract: A document reading apparatus has a slit along one side of a document support platen of a glass plate to insert one part of an opened book as a document to be read. An insertion pocket forming a recessed space contiguous with the slit and inclined diagonally is provided in the apparatus. A lid is operable between open and closed positions exposing and covering the slit. In the open position, one part of a book can be inserted into the slit with a page in the other part of the book being in intimate contact with the platen, while in the closed position, a sheet as a document can be placed at a proper position on the platen by contacting one side of the sheet to a rim of the lid. This apparatus prevents a problem of image deformation and black image in print output when reading the book.

Abstract: A water-soluble acylated chitosan having a degree of acylation of 35 to 65% is prepared by dissolving a water-insoluble chitosan in the form of a random copolymer having a degree of deacetylation of at least 70% in an aqueous acid solution, diluting the solution with water or a water-miscible solvent such as methanol, and adding an acylation agent such as acetic anhydride to the diluted solution. The acylated chitosan is obtained in high yields within a few hours at about room temperature.

Abstract: An artificial saliva composition comprising at least one buffering compound selected from the group consisting of chitins and chitosans in a medium. The artificial saliva composition has a pH buffering capacity similar to natural saliva and an excellent caries preventing effect.

Abstract: Chitin or chitin derivatives compounded with oral compositions such as dentifrice, mouth rinse, oral freshener, chewing gum and the like exhibit superior medicine effects for the prevention of dental caries, periodontoclasia and mouth odor. And, chitosan salt is also effective as the binding agent for use in the above mentioned oral compositions.