No abstract

Among the open problems in P2P systems, support for non-trivial search predicates, standardized query languages, distributed query processing, query load balancing, and quality of query results have been identified as some of the most relevant issues. This paper describes how range queries as an important non-trivial search predicate can be supported in a structured overlay network that provides O(log n) search complexity on top of a trie abstraction. We provide analytical results that show that the proposed approach is efficient, supports arbitrary granularity of ranges, and demonstrate that its algorithmic complexity in terms of messages is independent of the size of the queried ranges and only depends on the size of the result set. In contrast to other systems which provide evaluation results only through simulations, we validate the theoretical analysis of the algorithms with large-scale experiments on the PlanetLab infrastructure using a fully-fledged implementation of our approach.

The P-Grid approach enables distributed search and replication.Gridella, a P2P system based on P-Grid, improves on Gnutella's search performance while reducing bandwidth requirements.

Antimalarial peroxides such as the phytochemical artemisinin or the synthetic ozonides arterolane and artefenomel undergo reductive cleavage of the pharmacophoric peroxide bond by ferrous heme, released by parasite hemoglobin digestion. The generated carbon-centered radicals alkylate heme in an intramolecular reaction and proteins in an intermolecular reaction. Here, we determine the proteinaceous alkylation signatures of artemisinin and synthetic ozonides in Plasmodium falciparum using alkyne click chemistry probes to identify target proteins by affinity purification and mass spectrometry-based proteomics. Using stringent controls and purification procedures, we identified 25 P. falciparum proteins that were alkylated by the antimalarial peroxides in a peroxide-dependent manner, but the alkylation patterns were more random than we had anticipated. Moreover, there was little overlap in the alkylation signatures identified in this work and those disclosed in previous studies. Our findings suggest that alkylation of parasite proteins by antimalarial peroxides is likely to be a nonspecific, stochastic process.