Grid sensitivity analysis

This paper presents a method to compute the sensitivities of displacements and natural frequencies to the changes in grid locations. The sensitivities are computed within using the semi-analytical method via a program. New software was developed to assist in the selection of design variables and plot the spatial variation of the sensitivities on the finite element model. Two example problems demonstrate the technique.     

Improved machine learning scoring functions for identification of Electrophorus electricus’s acetylcholinesterase inhibitors

Molecular Diversity - Structure-based drug design (SBDD) is an important in silico technique, used for the identification of enzyme inhibitors. Acetylcholinesterase (AChE), obtained from...     

Marine natural products: fistularin-1, -2 and -3 from the sponge Aplysina fistularis forma fulva

Three new high molecular weight bromotyrosine-related metabolites, $\text{3a}$, $\text{4a}$ and $\text{5a}$, were isolated from the sponge Aplysina ( Verongia) fistularis forma fulva, and their structures were determined from high resolution ¹H NMR and other spectroscopic data. The new metabolites are formally derived by combination of major segments of two known Aplysina metabolites $\text{1a}$ and $\text{2}$.     

Synthesis of functionalized pyrroles and fused pyrroles through intermolecular [3 + 2] cycloaddition reaction

A facile and efficient synthesis of pyrrole and pyrrole-fused heterocyclic compounds has been demonstrated. The current protocol involves the in situ generation of azomethine ylides which undergoes intermolecular cycloaddition reaction and subsequent treatment with DDQ provides the pyrrole and fused heterocyclic compounds in good yields.     

Rapid Validated RP-HPTLC Method for the Quantification of Major Bioactive Constituents of Crataegus oxyacantha L.

JPC – Journal of Planar Chromatography – Modern TLC - A reverse phase high-performance thin-layer chromatography (RPHPTLC) method was developed for determination of vitexin, hyperoside,...     

Nanoparticle-enhanced sensitivity of a nanogap-interdigitated electrode array impedimetric biosensor

Interdigitated electrode (IDE) arrays with nanometer-scale gaps have been utilized to enhance the sensitivity of affinity-based detection. The geometry of nanogap IDEs was first optimized on the basis of simulations of the electric field and current density. It was determined that the gap (G) between the electrodes was the most important geometric parameter in determining the distribution and strength of the electric field and the current density compared to the width (W) and height (H) of the IDEs. Several devices were materialized and analyzed for their sensitivity to the electrochemical environment using faradic electrochemical impedance spectroscopy (EIS) as the detection technique. Nanogap optimized IDEs were then employed as biosensors for the label-free, affinity-based detection of antitissue transglutaminase antibodies (αtTG-Abs), a biomarker for the detection of autoimmune disorder celiac sprue, triggered by ingesting gluten. The label-free biosensor assay was found to be less sensitive compared to on-chip ELISA. Gold nanoparticles (GNPs) were then employed to improve the sensitivity of the nanogap IDE-based biosensor. With GNPs, the transducer sensitivity increased by 350% over that of label-free detection. The suitability of nanogap IDEs as biosensor transducers for EIS in label-free and GNP-labeled formats was established. The immunobiosensor assay detection sensitivity with the GNPs was found comparable to ELISA.     

Simultaneous Quantification of Flavonoids and Biflavonoids in Ginkgo biloba Using RP-HPTLC Densitometry Method

JPC – Journal of Planar Chromatography – Modern TLC - A reversed-phase high-performance thin-layer chromatography (RP-HPTLC) method was developed for the determination of flavonoids...     

An efficient microwave assisted extraction of phenolic compounds and antioxidant potential of Ginkgo biloba

Flavonoid glycosides are a significant group of compounds found in Ginkgo biloba leaves, but the long extraction procedures in existing methods are a challenging problem. In this work, a microwave-assisted extraction (MAE) method has been developed for extracting bioactive compounds from G. biloba. Several variables were optimized, such as extracting solvent, microwave power, and extraction time that can potentially affect the extraction yield. The total phenolic content, antioxidant activity (using DPPH, ABTS and FRAP assays) and flavonoid glycosides of different extracts using RP-HPLC were assessed. The antioxidant capacity was found to be highest with MAE using 60% aq. ethanol as extracting solvent and microwave power of 120W for 20 min.