Simultaneous determination of sesquiterpenes and pyrrolizidine alkaloids from the rhizomes of Petasites hybridus (L.) G.M. et Sch. and dietary supplements using UPLC-UV and HPLC-TOF-MS methods.

UPLC-UV and HPLC-TOF-MS methods have been developed for the analysis of major sesquiterpenes and pyrrolizidine alkaloids from rhizomes of Petasites hybridus (L.) G.M.

Exploring the molecular basis of antifungal synergies using genome-wide approaches.

Drug resistance poses a significant challenge in antifungal therapy since resistance has been found for all known classes of antifungal drugs. The discovery of compounds that can act synergistically with antifungal drugs is an important strategy to overcome resistance. For such combination therapies to be effective, it is critical to understand the molecular basis for the synergism by examining the cellular effects exerted by the combined drugs.

A gravity-driven low-rate particle feeder.

A gravity-driven particle feeder has been designed, fabricated, and tested to feed particles at low rates. A solenoid and a digital timer regulate the feed rate. This design avoids moving parts at the system periphery and thus avoids possible air leakages.

Physicochemical properties of highly conductive urea-EtMeImCl melts.

Urea-EtMeImCl mixtures have melting points from 333 to 363 K at 10-80 mol% urea, and, at temperatures >343 K, these melts show the highest conductivity reported to date for urea-based binary melts.

Total synthesis and absolute configuration of laurenditerpenol: a hypoxia inducible factor-1 activation inhibitor.

The absolute stereo structure of the natural product laurenditerpenol (1S, 6R, 7S, 10R, 11R, 14S, 15R) has been accomplished from eight plausible stereoisomers by its first asymmetric total synthesis in a highly convergent and flexible synthetic pathway. Six stereoisomers of laurenditerpenol were synthesized and evaluated for their biological activity.

Synthesis of a non-cationic, water-soluble perylenetetracarboxylic diimide and its interactions with G-quadruplex-forming DNA.

A number of N,N'-disubstituted perylenetetracarboxylic diimides have been reported to bind effectively to DNA that adopts G-quadruplex motifs. In some cases, this binding may actively drive the transition from single-strand DNA to the quadruplex form. The perylenediimides in the reported cases all have amine-containing side chains, which are thought to interact with the grooves of the quadruplex and help dictate the selectivity of these compounds for quadruplex versus duplex DNA.

Circular dichroism, a powerful tool for the assessment of absolute configuration of flavonoids.

Circular dichroism is a powerful tool for establishing the absolute configuration of flavonoids and proanthocyanidin analogues. It has been utilized to study the configuration of flavanones, dihydroflavonols (3-hydroxyflavanones), flavan-3-ols, flavan-4-ols, flavan-3,4-diols, flavans, isoflavans, isoflavanones, pterocarpans, 6a-hydroxypterocarpans, rotenoids, 12a-hydroxyrotenoids, neoflavonoids, 3,4-dihydro-4-arylcoumarins, 4-arylflavan-3-ols, auronols, homoisoflavanones, proanthocyanidins, and various classes of biflavonoids. Results relevant to the correlation of circular dichroic data and the absolute configuration of the diastereoisomers of some of the above classes of compounds will be discussed.

Design and construction of wetlands for aqueous transfers and transformations of selected metals.

Two pilot-scale wetland cells (6.1 x 30.5 m) were integratively designed and constructed to emphasize and enhance transfers and transformations of selected metals (Cu, Pb, and Zn) in an aqueous matrix.

An analysis of antigen-antibody binding kinetics for biosensor applications utilized as a model system: influence of non-specific binding.

The influence of non-specific binding on the specific binding of antigen in solution to antibody immobilized on a biosensor surface is presented for first-, one and a half-, second-, and other order reactions occurring under external diffusion-limited conditions. Both single-step and dual-step binding of antigen to antibody is considered. For a half-order reaction the value of the ratio of non-specific binding to specific binding (alpha) does not affect the rate of specific binding since a single curve represents the binding curve for alpha = 0 to 0.

Detection and Characterization of Cocaine and Related Tropane Alkaloids in Coca Leaf, Cocaine, and Biological Specimens.

Cocaine, atropine and scopolamine are the three most important alkaloids in the tropane group. The detection of these alkaloids and their metabolites, at trace levels in biological matrices, is reviewed. These matrices include human and rat physiological fluids such as blood, urine, and saliva as well as human body tissue and hair.

Use of aquatic organisms as models to determine the in vivo contribution of flavin-containing monooxygenases in xenobiotic biotransformation.

In an attempt to understand the evolution and role of flavin-containing monooxygenases (FMOs) in xenobiotic biotransformation by aquatic organisms, a survey of hepatic FMO activity (N,N-dimethylaniline N-oxidase and thiourea oxidase) was performed in one brackish water fish and 17 species of freshwater fish, one of which was anadromous. Only hepatic microsomes from the brackish water medaka (Oryzia latipes), the freshwater centrarid Lepomis macrochirus, and the anadromous rainbow trout (Oncorhynchus mykiss) consistently demonstrated FMO activity. Previous studies in trout have shown that the carbarmate insecticide, aldicarb, is bioactivated through an FMO-catalyzed S-oxidation.

Decomposition of arteether in simulated stomach acid yielding compounds retaining antimalarial activity.

In simulated stomach acid (aqueous 0.01 M HCl, 37 degrees C) beta-arteether decomposed (half-life, 441 +/- 17 min) to dihydroartemisinin, which subsequently rearranged to a new compound (1) having an endoperoxide group and an aldehyde group. The in vitro antimalarial activity of dihydroartemisinin is similar to that of beta-arteether, whereas compound 1 had approximately 1/10th the activity of beta-arteether.

Microbial models of mammalian metabolism: fungal metabolism of the diterpene sclareol by Cunninghamella species.

Microbial metabolism of the diterpene sclareol was studied. Screening studies have shown a number of microorganisms capable of metabolizing sclareol. Preparative scale fermentation with Cunninghamella species NRRL 5695 has resulted in the production of two fungal metabolites that have been characterized as 3 beta-hydroxysclareol and 18-hydroxy-sclareol with the use of 2D nmr techniques.

Myofunctional and dentofacial relationships in second grade children.

One hundred and thirty-three second graders in rural public school were assessed on a number of dental, skeletal, and oral muscle function measures. Correlational analyses were conducted in order to determine whether specific myofunctional variables were associated with dentofacial development. Significant relationships were observed between open mouth posture and a narrow maxillary arch and long facial height.