To the Editor; Tramadol, a synthetic opioid is mainly used to treat acute and chronic pain. Although this drug is not an over-the-counter medication, it has been illicitly accessible to and abused by opium addicts (1-3). Studies showed excessive and widespread use of tramadol in Iran (1-4). Tramadol may cause constipation, drowsiness, tachycardia and respiratory distress, while the most severe...

Histidine transfer RNA (tRNA) is unique among tRNA species as it carries an additional nucleotide at its 5' terminus. This unusual G(-1) residue is the major tRNA(His) identity element, and essential for recognition by the cognate histidyl-tRNA synthetase to allow efficient His-tRNA(His) formation. In many organisms G(-1) is added post-transcriptionally as part of the tRNA maturation process. t...

The goal of a distributed denial of service (DDoS) attack is to completely tie up certain resources so that legitimate users are not able to access a service. It has long been an open security problem of the Internet. In this paper, we identify a class of stateful DDoS attacks that defeat the existing cookie-based solutions. To counter these attacks, we propose a new defense mechanism, called t...

S. Pislak, P. Robmann and P. Tru ol, in collaboration with J. Egger, W. D. Herold, H. Kaspar, and H. Weyer, Paul{Scherrer{Institut, CH-5234 Villigen Brookhaven National Laboratory, Upton, NY-11973, USA University of New Mexico, Albuquerque, NM-87131, USA University of Pittsburgh, Pittsburgh, PA-15260, USA Yale University, Newhaven, CT-06511, USA Institute for Nuclear Research, Academy of Scien...

Many peer-to-peer security protocols proposed for wireless communications use one-time shared secrets for authentication purposes. This paper analyses online update mechanisms for one-time shared secrets. A new type of attack against update mechanisms, called desynchronisation attack, is introduced. This type of attack may lead to a permanent denial of service condition. A case study demonstrat...