RESUMO
AI Chat Bots such as ChatGPT are revolutionizing our AI capabilities, especially in text generation, to help expedite many tasks, but they introduce new dilemmas. The detection of AI-generated text has become a subject of great debate considering the AI text detector's known and unexpected limitations. Thus far, much research in this area has focused on the detection of AI-generated text; however, the goal of this study was to evaluate the opposite scenario, an AI-text detection tool's ability to discriminate human-generated text. Thousands of abstracts from several of the most well-known scientific journals were used to test the predictive capabilities of these detection tools, assessing abstracts from 1980 to 2023. We found that the AI text detector erroneously identified up to 8% of the known real abstracts as AI-generated text. This further highlights the current limitations of such detection tools and argues for novel detectors or combined approaches that can address this shortcoming and minimize its unanticipated consequences as we navigate this new AI landscape.
RESUMO
The previously unexplored metal-catalyzed [5 + 2] cycloadditions of vinylcyclopropanes (VCPs) and electron-rich alkynes (ynol ethers) have been found to provide a highly efficient, direct route to dioxygenated seven-membered rings, a common feature of numerous natural and non-natural targets and building blocks for synthesis. The reactions proceed in high yield at room temperature and tolerate a broad range of functionalities. Substituted VCPs were found to react with high regioselectivity.
Assuntos
Éteres/química , Alcinos , Catálise , Reação de Cicloadição , Etilenos , Cetonas , Estrutura Molecular , RódioRESUMO
Ligand cross-linking is known to improve the colloidal stability of nanoparticles, particularly in aqueous solutions. However, most cross-linking is performed chemically, in which it is difficult to limit interparticle cross-linking, unless performed at low concentrations. Photochemical cross-linking is a promising approach but usually requires ultraviolet (UV) light to initiate. Using such high-energy photons can be harmful to systems in which the ligand-nanoparticle bond is fairly weak, as is the case for the commonly used semiconductor quantum dots (QDs). Here, we introduce a novel approach to cross-link thiolated ligands on QDs by utilizing the photocatalytic activity of QDs upon absorbing visible light. We show that using visible light leads to better ligand cross-linking by avoiding the problem of ligand dissociation that occurs upon UV light exposure. Once cross-linked, the ligands significantly enhance the colloidal stability of those same QDs that facilitated cross-linking.
Assuntos
Acetileno/química , Coloides/química , Reagentes de Ligações Cruzadas/química , Pontos Quânticos/química , Compostos de Sulfidrila/química , Água/química , Catálise , Ligantes , Luz , Luminescência , SemicondutoresRESUMO
This research investigates the synthesis and inhibitory potency of a series of novel dipeptidyl allyl sulfones as clan CA cysteine protease inhibitors. The structure of the inhibitors consists of a R(1)-Phe-R(2)-AS-Ph scaffold (AS = allyl sulfone). R(1) was varied with benzyloxycarbonyl, morpholinocarbonyl, or N-methylpiperazinocarbonyl substituents. R(2) was varied with either Phe of Hfe residues. Synthesis involved preparation of vinyl sulfone analogues followed by isomerization to allyl sulfones using n-butyl lithium and t-butyl hydroperoxide. Sterics, temperature and base strength were all factors that affected the formation and stereochemistry of the allyl sulfone moiety. The inhibitors were assayed with three clan CA cysteine proteases (cruzain, cathepsin B and calpain I) as well as one serine protease (trypsin). The most potent inhibitor, (E)-Mu-Phe-Hfe-AS-Ph, displayed at least 10-fold selectivity for cruzain over clan CA cysteine proteases cathepsin B and calpain I with a (kobs)/[I] of 6080 ± 1390 M(-1)s(-1).