Topic
NQS
About: NQS is a research topic. Over the lifetime, 337 publications have been published within this topic receiving 4226 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: The proposed spectrophotometric method based on the reaction of glycine and lysine with 1,2-naphthoquinone-4-sulfonate in slightly basic medium was applied to the determination of considered amino acids in synthetic samples.
40 citations
15 May 2002
TL;DR: In this article, high frequency (HF) AC and noise modeling of MOSFETs for low noise, radio frequency (RF) integrated circuit (IC) design are discussed.
Abstract: In this paper, high frequency (HF) AC and noise modeling of MOSFETs for low noise, radio frequency (RF) integrated circuit (IC) design are discussed. Scalable parasitic model and the Non-Quasi-Static (NQS) model are discussed and verified with the measured data. For the noise modeling, extracted noise sources of MOSFETs in 0.18 μm CMOS process and from RF noise measurements are presented. Finally, the design consideration including selection of device size, bias condition and design of the device geometry are discussed.
39 citations
TL;DR: This review analyzes the more recent publications concerning the distribution, chemistry, and bioactivities of naphthoquinones in higher plants and underlines the importance of NQs in taxonomy, Chemistry, and their bioactive potential as novel biocides and chemotherapeutic agents.
Abstract: This review analyzes the more recent publications concerning the distribution, chemistry, and bioactivities of naphthoquinones (NQs) in higher plants. These highly reactive molecules have a diverse distribution in nature being isolated from bacteria, algae, fungi, lichens, insects, and higher plants, where they mostly occur in Eudicots. Over 200 species reported to produce NQs are listed according to orders and families. Out of 65 orders, only 16 report their occurrence, suggesting that the phylogenetically more advanced orders (Caryophyllales, Ericales, and Lamiales) have a higher percentage of NQ-producing families. Certain classes of NQs appear confined to certain orders. Chemically, the NQs found range from simple monomeric 1, 4- and 1, 2-NQ isomers to dimers, trimers, and tetramers, as well as furano, pyrano, and prenylated derivatives. The major bioactivities are summarized, including cytotoxicity and antitumor (a-dunnione, plumbagin, and shikonin), antibacterial (diospyrin), anti-inflammatory (iso-eleutherin), antiparasitic (sterekunthal A), antifungal (droserone). Some NQs are considered to be phytoalexins (e.g., O-hibiscanone induced by fungal infection of Hibiscus cannabinus with Verticillium dahliae ). Many of these activities are associated with their inhibition of electron transport, uncoupling of oxidative phosphorylation, and their intercalation with DNA. Many NQ-containing plants are of importance to humans, commercially as dyes (lawsone, shikonin) or as medicines in systems of Traditional Medicine (e.g., Lapacho, a herbal medicine used by South and Central American indigenous peoples to treat ailments including infection, fever, and stomach complaints). The review underlines the importance of NQs in taxonomy, chemistry, and their bioactive potential as novel biocides and chemotherapeutic agents.
36 citations
TL;DR: The relationship of mutagenic potency to the one-electron reduction potential with TA104 suggested that the higher redox potential NQs were more Mutagenic than the lower redoxpotential NZs, and the cytotoxic effect of the N Qs was largely dependent on the structures of their substituents.
Abstract: The molecular mechanisms involved in quinone cytotoxicity, especially mutagenicity, are still largely unknown. In order to better understand the molecular aspects of the mechanisms of quinone mutagenicity and cytotoxicity, we examined them by using a series of 13 simple structural naphthoquinone (NQ) derivatives for 9 Ames Salmonella mutagenicity tester strains in the presence of absence of liver homogenate S9 mix from rats induced with phenobarbital and 5,6-benzoflavone. Most NQs used in this study showed mutagenicity with and/or without S9 mix. The most potent mutagenic NQ was 2,3-dichloro-1,4-NQ, with mutagenicity of 18 induced revertants/nmol/plate for strain TA104 without S9 mix. Among the strains used, TA104, which is sensitive to oxidative mutagens, was the most sensitive to the NQs, and the second most sensitive strain was TA2637, which detects bulky DNA adducts. The relationship of mutagenic potency to the one-electron reduction potential with TA104 suggested that the higher redox potential NQs were more mutagenic than the lower redox potential NQs. Significant reduction of the mutagenicity of 1,4-naphthoquinone without S9 mix was observed in the presence of catalase. Enhancement of the mutagenic potential of the NQs by the pKM101 plasmid implicated in error-prone repair was also observed. The most cytotoxic NQ was 2,3-dichloro-5,8-dihydroxy-1,4-NQ, and the least cytotoxic NQ was beta-NQ-4-sulfonic acid potassium salt, a 700-fold range in potency. The cytotoxic effect of the NQs was largely dependent on the structures of their substituents.(ABSTRACT TRUNCATED AT 250 WORDS)
36 citations
TL;DR: The proposed spectrophotometric method was successfully applied to the determination of FXM in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was 100.47+/-0.96%.
35 citations