Chemicals and Drugs Commons^™

A Model For The Voltammetric Behaviour Of Tio2 Memristors, John Cassidy, Daryl Fox, Tony Betts

Articles

Abstract A model is solved based on the Nernst Planck equation to calculate the diffusion and migration currents for a species in a thin layer (about 200 nm) confined between two electrodes. This is proposed to account for the current voltage behaviour of a memristor constructed in a similar fashion. At the working electrode, an electroactive species is oxidised and at the counter electrode, the same species is reduced. Upon application of a simple voltammetric waveform, the migration current exhibits a resistance profile at slow scan rates and hysteresis at faster scan rates, indicative of memristor behavior.

Nitrogen And Phosphorus Availability From Various Composted Wastes For Use In Irish Agriculture And Horticulture, Alan Lee

Doctoral

Current environmental EU legislation promotes recycling and recovery from organic waste products. Compost has been identified as an alternative to inorganic fertilisers and animal slurries as a nutrient source for crop plants. This study aimed to investigate nitrogen (N) and phosphorus (P) availability from various composted waste through detailed characterisations, complemented by short term lab incubations and long term plant growth experiments. Twenty-five composts were selected and classified by their groups. The composts were characterised by multiple different analytical techniques. Two incubation studies were conducted. One investigating N and P mineralisation potential of the composts and the second on the …

Piperlongumine (Piplartine) And Analogues: Antiproliferative Microtubule-Destabilising Agents, Mary J. Meegan, Seema M. Nathwani, Brendan Twamley, Daniela M. Zisterer, Niamh O'Boyle

Articles

Piperlongumine (piplartine, 1) is a small molecule alkaloid that is receiving intense interest due to its antiproliferative and anticancer activities. We investigated the effects of 1 on tubulin and microtubules. Using both an isolated tubulin assay, and a combination of sedimentation and Western blotting, we demonstrated that 1 is a tubulin-destabilising agent. This result was confirmed by immunofluorescence and confocal microscopy, which showed that microtubules in MCF-7 breast cancer cells were depolymerised when treated with 1. We synthesised a number of analogues of 1 to explore structure-activity relationships. Compound 13 had the best cytotoxic profile of this series, …

Influence Of Ionic Liquids On The Selectivity Of Ion Exchange-Based Polymer Membrane Sensing Layers, Lukasz Mendecki, Nicole Callan, Meghan Ahern, Benjamin Schazmann, Aleksandar Radu

Articles

The applicability of ion exchange membranes is mainly defined by their permselectivity towards specific ions. For instance, the needed selectivity can be sought by modifying some of the components required for the preparation of such membranes. In this study, a new class of materials –trihexyl(tetradecyl)phosphonium based ionic liquids (ILs) were used to modify the properties of ion exchange membranes. We determined selectivity coefficients for iodide as model ion utilizing six phosphonium-based ILs and compared the selectivity with two classical plasticizers. The dielectric properties of membranes plasticized with ionic liquids and their response characteristics towards ten different anions were investigated using …

Artemisinin Production By Plant Hairy Root Cultures In Gas- And Liquid-Phase Bioreactors, Nivedita Patra, Ashok K. Srivastava

Articles

Key message

Alternative biotechnological protocol for large-scale artemisinin production was established. It featured enhanced growth and artemisinin production by cultivation of hairy roots in nutrient mist bioreactor (NMB) coupled with novel cultivation strategies.

Artemisinin is used for the treatment of cerebral malaria. Presently, its main source is from seasonal plant Artemisia annua. This study featured investigation of growth and artemisinin production by A. annua hairy roots (induced by Agrobacterium rhizogenes-mediated genetic transformation of explants) in three bioreactor configurations—bubble column reactor, NMB and modified NMB particularly to establish their suitability for commercial production. It was observed that cultivation of …

Synthesis And Biochemical Evaluation Of 3-Phenoxy-1,4-Diarylazetidin-2-Ones As Tubulin-Targeting Antitumor Agents, Thomas F. Greene, Shu Wang, Lisa M. Greene, Seema M. Nathwani, Jade K. Pollock, Azizah M. Malebari, Thomas Mccabe, Brendan Twamley, Niamh O'Boyle, Daniela M. Zisterer, Mary J. Meegan

Articles

Structure-activity relationships for a series of 3-phenoxy-1,4-diarylazetidin-2-ones were investigated leading to the discovery of a number of potent antiproliferative compounds, including trans-4-(3-hydroxy-4-methoxyphenyl)-3-phenoxy-1-(3,4,5-trimethoxyphenyl)azetidin-2-one (78b) and trans-4-(3-amino-4-methoxyphenyl)-3-phenoxy-1-(3,4,5-trimethoxyphenyl)azetidin-2-one (90b). X-ray crystallography studies indicate the potential importance of the torsional angle between the 1-phenyl ‘A’ ring and 4-phenyl ‘B’ ring for potent antiproliferative activity, and that a trans configuration between the 3-phenoxy and 4-phenyl rings is generally optimal. These compounds displayed IC₅₀ values of 38 nM and 19 nM respectively in MCF-7 breast cancer cells, inhibited the polymerization of isolated tubulin in vitro, disrupted the microtubular …