Research Triangle Park

About: Research Triangle Park is a nonprofit organization based out in Durham, North Carolina, United States. It is known for research contribution in the topics: Population & Environmental exposure. The organization has 24961 authors who have published 35800 publications receiving 1684504 citations. The organization is also known as: RTP.

Crystal structure of the anti-bacterial sulfonamide drug target dihydropteroate synthase.

Abstract: Sulfonamides were amongst the first clinically useful antibacterial agents to be discovered. The identification of sulfanilamide as the active component of the dye Prontosil rubrum led to the synthesis of clinically useful analogues. Today sulfamethoxazole (in combination with trimethoprim), is used to treat urinary tract infections caused by bacteria such as Escherichia coli and is also a first-line treatment for pneumonia caused by the fungus Pneumocystis carinii, a common condition in AIDS patients. The site of action is the de novo folate biosynthesis enzyme dihydropteroate synthase (DHPS) where sulfonamides act as analogues of one of the substrates, para-aminobenzoic acid (pABA). We report here the crystal structure of E.coli DHPS at 2.0 A resolution refined to an R-factor of 0.185. The single domain of 282 residues forms an eight-stranded alpha/beta-barrel. The 7,8-dihydropterin pyrophosphate (DHPPP) substrate binds in a deep cleft in the barrel, whilst sulfanilamide binds closer to the surface. The DHPPP ligand site is highly conserved amongst prokaryotic and eukaryotic DHPSs.

Size Distribution of Fine Particles from Coal Combustion

Abstract: Measurements of the particle size distribution at the outlets of six coal-fired utility boilers showed a peak at a particle diameter near 0.1 micrometer. This submicrometer mode appears to be a general feature of coal combustion that results from a volatilization-condensation process in the boiler. At the boilers tested, the submicrometer mode contained 0.2 to 2.2 percent of the total fly ash mass. The importance of this mode is greater than its small quantity suggests because particles in the submicrometer size range are often much more difficult to collect with conventional particulate control devices than larger particles. Thus, the submicrometer mode may significantly influence the design and selection of future power plant emission controls. The particle mass in the submicrometer mode was correlated with the nitric oxide concentration in the flue gas. This correlation suggests that control of nitric oxide by modification of the combustion conditions may reduce the generation and emission of submicrometer particles.

Electronic mail forwarding system and method

Abstract: A mail forwarding system is provided for use in a private network system (12) having a server (16), a fixed computer (20) and a router (18) for connection to a public network (14) external to the private network, all interconnected via a data connection, with the server controlling electronic mail resources addressed to a user of the fixed computer received by the private network. The mail forwarding system includes a mail forwarding program (32) operating in the fixed computer for controlling the fixed computer to selectively (a) retrieve electronic mail addressed to the user of the fixed computer from the private network (12) and (b) transmit the received electronic mail via the router to an assigned address (28) in the public network accessible by a communicator (30) remote from the private network.