Recent advances in the MS analysis of glycoproteins: Capillary and microfluidic workflows

Recent developments in bioanalytical instrumentation, MS detection, and computational data analysis approaches have provided researchers with capabilities for interrogating the complex cellular glycoproteome, to help gain a better insight into the cellular and physiological processes that are associated with a disease and to facilitate the efforts centered on identifying disease-specific biomarkers. This review describes the progress achieved in the characterization of protein glycosylation by using advanced capillary and microfluidic MS technologies. The major steps involved in large-scale glycoproteomic analysis approaches are discussed, with special emphasis given to workflows that have evolved around complex MS detection functions. In addition, quantitative analysis strategies are assessed, and the bioinformatics aspects of glycoproteomic data processing are summarized. The developments in commercial and custom fabricated microfluidic front-end platforms to ESI- and MALDI-MS instrumentation, for addressing major challenges in carbohydrate analysis such as sensitivity, throughput, and ability to perform structural characterization, are further evaluated and illustrated with relevant examples.     

Artemisinin evaluation in Romanian Artemisia annua wild plants using a new HPLC/MS method

Artemisinin, a sesquiterpene lactone from Artemisia annua L., has received considerable attention in the last few decades as a potent antimalarial drug. Artemisinin has rather low toxicity; it is effective against drug-resistant Plasmodium species and against cerebral malaria. This study reports the development of a rapid and sensitive assay for the quantification of artemisinin in A. annua by reversed phase HPLC/MS. In the selected optimal experimental conditions, artemisinin exhibited a well-defined chromatographic peak with a retention time of 2 ± 0.2 min. The chromatographic signal shows a linear dependence with artemisinin concentration, enabling the use of this signal for artemisinin quantification according to the following regression equation: y = 2665.40x - 14697.61. The correlation coefficient (R(2)) was 0.9989. For every concentration within the range of the standard curve (0.1-2 μg mL(-1)), accuracy was between 95 and 104%. Artemisinin content in Romanian A. annua wild plants varies between 0.17 and 0.21% (dry weight basis).     

A characterization of duality through section/projection correspondence in the finite dimensional setting

In this paper, we show that the well-known duality operation in the context of convex bodies in Rn is completely characterized by its property of interchanging sections with projections. Our results are compared to results by Böröczky-Schneider and Artstein-Milman, who showed that in many cases, the property of order reversing is sufficient to determine a duality operation, up to obvious linear modifications. In fact, we provide another result that recovers a known characterization of duality by the property of order reversing, and up to a mild condition, also a characterization of duality by interchanging sections by projections.     

A Generalized Two-Agent Location Problem: Asymmetric Dynamics and Coordination

We generalize a static two-agent location problem into dynamic, asymmetric settings. The dynamics is due to the ability of the agents to move at limited speeds. Since each agent has its own objective (demand) function and these functions are interdependent, decisions made by each agent may affect the performance of the other agent and thus affect the overall performance of the system. We show that, under a broad range of system’s parameters, centralized (system-wide optimal) and non-cooperative (Nash) behavior of the agents are characterized by a similar structure. The timing of these trajectories and the intermediate speeds are however different. Moreover, non-cooperative agents travel more and may never rest and thus the system performance deteriorates under decentralized decision-making. We show that a static linear reward approach, recently developed in Golany and Rothblum (Nav. Res. Logist. 53(1):1–15, 2006), can be generalized to provide coordination of the moving agents and suggest its dynamic modification. When the reward scheme is applied, the agents are induced to choose the system-wide optimal solution, even though they operate in a decentralized decision-making mode.     

Stereochemistry of the sn2′ displacement of chiral 1, 3-disubstituted bromoallenes to form chiral acetylenes

Optically active 1,3-disubstituted bromoallenes react with a variety of cuprate reagents preferentially in an S_N2′ fashion with very high $\text{anti}$ selectivity.     

Contributions to the analytical chemistry of osmium and ruthenium-IX: the dimercapto derivatives of asymmetric triazine as colour reagents for osmium

The parameters of the reaction of osmium with 3,5-dimercapto-6-(ethylcarboxy)-1,2,4-triazine have been studied and the optimum conditions for the spectrophotometric determination of osmium over the range 0.5-18.0 ppm determined. The coloured product contains the components in the ratio 1:2 metal:ligand.