Chemistry Commons^™

Advancing Competency In Managing Risk And Knowledge: Steps Toward Operationalisation Of The Risk-Knowledge Infinity Cycle (Rki Cycle) - Part 1: Improving Effectiveness Of Risk-Based Decision Making (Rbdm), Martin Lipa, Paige Kane, Anne Greene

Articles

To date, literature on the Risk-Knowledge Infinity Cycle (RKI Cycle) has mainly been theoretical. This paper series intent is to focus on the operationalisation of the RKI Cycle by describing a series of steps – the “How to” – for RKI Cycle deployment, to help move the RKI Cycle from theory to practice. The first paper in this series focuses on how the RKI Cycle can support effective Risk-Based Decision Making (RBDM).

Analysis Of Copper(Ii) Using The Ascorbate/Oxygen System – A Valuable Undergraduate Resource, Sean Tobin, John Cassidy, Kevin Kurian, Tony Betts

Articles

In deionised water, ascorbic acid (AH−), through oxidation by oxygen in the presence of copper(II), was found to degrade with zero-order kinetics. The magnitude of the reaction rate varied directly with the copper(II) concentration. At a higher pH (7.4), the same reaction was found to be pseudo-first order. Once again, the magnitude of the rate increased linearly with copper(II) concentration at a micromolar level. Dissolved oxygen levels, in excess AH− and trace copper(II), displayed similar kinetics under both conditions. Monitoring of either AH− levels or dissolved oxygen concentration was found to be a useful novel undergraduate practical laboratory for trace …

Biomolecular Corona Stability In Association With Plasma Cholesterol Level, Duong N. Trinh, Meda Radlinskaite, Jack Cheeseman, Gunther Kuhnle, Helen M.I. Osborn, Paula Meleady, Daniel I.R. Spencer, Marco P. Monopoli

Articles

Biomolecular corona is spontaneously formed on the surface of nanoparticles (NPs) when they are in contact with biological fluids. It plays an important role in the colloidal stability of NPs, which is of importance for most of their medical applications and toxicity assessment. While typical studies use either blood plasma or serum from a pooled biobank, it is unclear whether differences in the media, such as cholesterol level or protein concentration, might affect the NP colloidal stability and corona composition. In this study, the silica corona was prepared at particularly low plasma concentrations (3%, v/v–1.98 mg/mL) to identify the critical …

A Nanoscale Shape-Discovery Framework Supporting Systematic Investigations Of Shape-Dependent Biological Effects And Immunomodulation, Wei Zhang, Hender Lopez, Luca Boselli, Paolo Bigini, André Perez-Potti, Zengchun Xie, Valentina Castagnola, Qi Cai, Camila P. Silveira, Joao M. De Araujo, Laura Talamini, Nicolò Panini, Giuseppe Ristagno, Martina B. Violatto, Stéphanie Devineau, Marco P. Monopoli, Mario Salmona, Valeria A. Giannone, Sandra Lara, Kenneth A. Dawson, Yan Yan

Articles

Since it is now possible to make, in a controlled fashion, an almost unlimited variety of nanostructure shapes, it is of increasing interest to understand the forms of biological control that nanoscale shape allows. However, a priori rational investigation of such a vast universe of shapes appears to present intractable fundamental and practical challenges. This has limited the useful systematic investigation of their biological interactions and the development of innovative nanoscale shape-dependent therapies. Here, we introduce a concept of biologically relevant inductive nanoscale shape discovery and evaluation that is ideally suited to, and will ultimately become, a vehicle for machine …

“Transitioning Organisations From A Data Quagmire To Knowledge Nirvana Through The Digital Thread”, David Twohig, Barry Heavey

Level 3

Historically, organisations have managed product data in a combination of Microsoft Office, Sharepoint and Document Management Systems. In this paper, we explore how different technologies can be leveraged to create digital product profiles, and in doing so structure data to enable effective knowledge management.

Synergistic Anticancer Response Of Curcumin And Piperine Loaded Lignin-G-P (Nipam-Co-Dmaema) Gold Nanogels Against Glioblastoma Multiforme, Xinyi Zhao, Bilal Javad, Daxing Cui, James Curtin, Furong Tian

Articles

Glioblastoma multiforme (GBM) is the most aggressive and commonly diag- 11 nosed brain cancer and presents a strong resistance to routine chemotherapeutic drugs. 12 The present study involves the synthesis of Lignin-g- p (NIPAM-co-DMAEMA) gold 13 nanogel, loaded with curcumin and piperine to treat GBM. The application has three 14 functions: (1) overcome the limitations of biodistribution, (2) enhance the toxicity of an- 15 ticancer drugs against GBM, (3) identify the uptake pathway. Atom transfer radical 16 polymerization was used to synthesize the Lignin-g-PNIPAM network, crosslinked with 17 the gold nanoparticles (GNPs) to self-assemble into nanogels. The size distribution and …

Immobilized-Enzyme Reactors Integrated Into Analytical Platforms: Recent Advances And Challenges, Bert Wouters Dr, Sinead Currivan, Noor Abdulhussain, T. Hankemeier, Peter J. Schoenmakers

Articles

Immobilized-enzyme reactors (IMERs) are flow-through devices containing enzymes that are physically confined or localized with retention of their catalytic activities. IMERs can be used repeatedly and continuously and have been applied for (bio)polymer degradation, proteomics, biomarker discovery, inhibitor screening, and detection. Online integration of IMERs with analytical instrumentation, such as high-performance liquid chromatography (HPLC) systems, reduces the time needed for multi-step workflows, reduces the need for sample handling, and enables automation. However, online integration can also be challenging, as reaching its full potential requires complex instrumental setups and experienced users. This review aims to provide an assessment of recent advances …

The 3d Printing Of Dielectric Elastomer Films Assisted By Electrostatic Force, Yuhao Wang, Yanfen Zhou, Wenyue Li, Zhanxu Liu, Bangzi Zhou, Shipeng Wen, Liang Jiang, Shaojuan Che, Jianwei Ma, Tony Betts, Stephen Jerrams, Fenglei Zhou

Articles

ompared with traditional methods for preparing dielectric elastomer (DE) films, electrohydrodynamic (EHD) 3D printing displays many advantages, notably full automation, computer control and flexible design. It also confers high printing resolution, high preparation efficiency with minimal probability of nozzle clogging. In this article, EHD 3D printing was employed to fabricate silicone rubber (SR) based DE films. In order to increase their dielectric constant, high dielectric copper phthalocyanine (CuPc) particles were added into the SR ink. Optimal printing conditions were determined by analyzing the effects of printing voltage and ink properties on the formation of liquid cone and the printed line …

Polyesters With Main And Side Chain Phosphoesters As Structural Motives For Biocompatible Electrospun Fibres, André E. Polloni, Viviane Chiaradia, Ronaldo José F.C. Do Amaral, Cathal Kearney, Brian Gorey, Débora De Oliveira, José V. De Oliveira, Pedro H.H. De Araújo, Claudia Sayer, Andreas Heise

Articles

Phosphoester containing polymers are promising materials in biomedical applications due to their biocompatibility and biodegradability. Utilising thiol-ene chemistry, the synthesis of two novel structural polymer motives combining polyesters and phophoester groups was explored. The first polymer was obtained by coupling ene-functional poly(thioether-phosphoester) with thiol functional poly(pentadecalactone). While the coupling reaction was successful, yields remained low presumably due to inadequate endgroup stoichiometry. The second polymer comprised phosphoester side groups conjugated to unsaturated poly(globalide). Double bond conversions up to 84% were achieved depending of the type of phosphoester thiol and relative reactant ratios. The resulting polymers transitioned from solid semicrystaline to liquid …

In Depth Characterisation Of The Biomolecular Coronas Of Polymer Coated Inorganic Nanoparticles With Differential Centrifugal Sedimentation, André Perez-Potti, Hender Lopez, Beatriz Pelaz, Abuelmagd Abdelmonem, Mahmoud G. Soliman, Ingmar Schoen, Philip M. Kelly, Kenneth A. Dawson, Wolfgang J. Parak, Zeljka Krpetic, Marco P. Monopoli

Articles

Advances in nanofabrication methods have enabled the tailoring of new strategies towards the controlled production of nanoparticles with attractive applications in healthcare. In many cases, their characterisation remains a big challenge, particularly for small-sized functional nanoparticles of 5 nm diameter or smaller, where current particle sizing techniques struggle to provide the required sensitivity and accuracy. There is a clear need for the development of new reliable characterisation approaches for the physico-chemical characterisation of nanoparticles with significant accuracy, particularly for the analysis of the particles in the presence of complex biological fluids. Herein, we show that the Differential Centrifugal Sedimentation can …

Fabrication Of Polymer Monoliths Within The Confines Of Non-Transparent 3d-Printed Polymer Housings, Noor Abdulhussain, Suhas H. Nawada, Sinéad Currivan, Marta Passamonti, Peter J. Schoenmakers

Articles

In the last decade, 3D-printing has emerged as a promising enabling technology in the field of analytical chemistry. Fused-deposition modelling (FDM) is a popular, low-cost and widely accessible technique. In this study, RPLC separations are achieved by in-situ fabrication of porous polymer monoliths, directly within the 3D-printed channels. Thermal polymerization was employed for the fabrication of monolithic columns in optically non-transparent column housings, 3D-printed using two different polypropylene materials. Both acrylate-based and polystyrene-based monoliths were created. Two approaches were used for monolith fabrication, viz. (i) in standard polypropylene (PP) a two-step process was developed, with a radical initiated wall-modification step …

Assessing The Correlation Of Microscopy-Based And Volumetry-Based Measurements For Resin Swelling In A Range Of Potential Greener Solvents For Spps, Jordan K. Magtaan, Marc Devocelle, Fintan Kelleher

Articles

The degree of resin swelling in a particular solvent system is one of the critical parameters for SPPS, and for solid phase synthesis, in general. Methods used for measuring the degree of resin swelling include microscopy-based and volumetry-based methods. This study describes, and compares, the use of both methods for a number of commercially available resins commonly used in SPPS, with a range of solvents which have been identified in the literature as “greener” than DCM, DMF and NMP. The results were analysed by statistical methods and a significant correlation between the two distinct methods has been demonstrated for the …

Use Of Confocal Raman Microscopy To Characterise Ethyl Cyanoacrylate Adhesive Depth Curing, Kevin Raheem, John Cassidy, Tony Betts, Bernard Ryan

Articles

In situ spatial temporal measurement of monomer conversion during adhesive bondline curing remains a challenging area. The aim of this work was to demonstrate the effectiveness of using confocal Raman microscopy in a specially configured experimental set-up, as a versatile tool for measuring monomer concentration changes as a function of both time and adhesive bond depth during ethyl cyanoacrylate polymerisation. This also allowed monitoring of the extent of polymerisation at the adhesive substrate interface independently of the bulk bondline polymerisation region. Key kinetic parameters such as inhibition time tlag, rate of reaction Rmax and extent of reaction [at]max were obtained …

Outstanding Reviewers For Analyst In 2019, Royal Society Of Chemistry

Articles

We would like to take this opportunity to thank all of Analyst's reviewers, and in particular highlight the Outstanding Reviewers for the journal in 2019, as selected by the editorial team for their significant contribution to Analyst. We announce our Outstanding Reviewers annually and each receives a certificate to give recognition for their contribution. The reviewers have been chosen based on the number, timeliness and quality of the reports completed over the last 12 months.

Advancement Of Predictive Modeling Of Zeta Potentials (Ζ) In Metal Oxide Nanoparticles With Correlation Intensity Index (Cii), Andrey A. Toropov, Natalia Sizochenko, Alla P. Toropova, Danuta Leszczynska, Jerzy Leszczynski

Articles

It was expected that index of the ideality of correlation (IIC) and correlation intensity index (CII) could be used as possible tools to improve the predictive power of the quantitative model for zeta potential of nanoparticles. In this paper, we test how the statistical quality of quantitative structure-activity models for zeta potentials (ζ, a common measurement that reflects surface charge and stability of nanomaterial) could be improved with the use of these two indexes. Our hypothesis was tested using the benchmark data set that consists of 87 measurements of zeta potentials in water. We used quasi-SMILES molecular representation to take …

Studies On The Synthesis Of Unusual Amino Acids And Their Incorporation Into New Peptide Antibiotics, Agnieszka Wadolowska

Doctoral

As microorganisms continue to develop resistance and survive against many different forms of antimicrobial solutions, such as antibiotics, there is urgent need for new classes of antimicrobial peptides to mitigate the threat. Bacteria are a rich source of ribosomally-synthesized antimicrobial peptides known as bacteriocins, which are produced by one bacterial species to kill other bacterial strains. Lanthionine-containing lantibiotics and sactibiotics are post-translationally modified bacteriocins which display extremely potent antibacterial activity.

Thuricin CD, a two-peptide system belonging to the sactibiotic family, shows high activity, but most importantly excellent selectivity, against C. difficile infection. The Thuricin CD peptides contain a number of …

The Fabrication And Properties Of Magnetorheological Elastomers Employing Bio-Inspired Dopamine Modified Carbonyl Iron Particles, Yanfen Zhou, Lele Li, Wenyue Li, Shipeng Wen, Liang Jiang, Stephen Jerrams, Jianwei Ma, Shaojuan Chen

Articles

To obtain magnetorheological elastomers (MREs) with improved mechanical properties and exhibiting an enhanced magnetorheological (MR) effect, bio-inspired dopamine modification has been used to improve the functionality at the surface of carbonyl iron (CI) particles. Various techniques including x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to confirm that a polydopamine (PDA) layer of about 27.5 nm had been successfully deposited on the surface of the carbonyl iron particles prior to their inclusion in the MRE composites. The magnetic properties of PDA modified CI particles were shown to be almost the same as those …

Singlet Oxygen Generation By Porphyrins And Metalloporphyrins Revisited: A Quantitative Structure-Property Relationship (Qspr) Study, Andrey A. Buglak, Mikhail Filatov, Althaf M. Hussain, Manabu Sugimoto

Books/Book chapters

state followed by formation of singlet oxygen (1O2), which is a highly reactive species and mediates various oxidative processes. The design of advanced sensitizers based on porphyrin compounds have attracted significant attention in recent years. However, it is still difficult to predict the efficiency of singlet oxygen generation for a given structure. Our goal was to develop a quantitative structure-property relationship (QSPR) model for the fast virtual screening and prediction of singlet oxygen quantum yields for pophyrins and metalloporphyrins. We performed QSPR analysis of a dataset containing 32 compounds, including various porphyrins and their analogues (chlorins and bacteriochlorins). Quantum-chemical descriptors …

Enhanced Covalent Interface, Crosslinked Network And Gas Barrier Property Of Functionalized Graphene Oxide/Styrene-Butadiene Rubber Composites Triggered By Thiol-Ene Click Reaction, Long Zheng, Stephen Jerrams, Tian Su, Zongchao Xu, Liqun Zhang, Li Liu, Shipeng Wen

Articles

The high gas barrier property of a rubber composite is of great significance for reducing the exhaust gas emissions due to tire rolling resistance and hence the contribution this factor makes to environmental protection. Enhanced covalent interfaces and crosslinked networks are crucial to the gas barrier property of rubber composites. In this research, γ-mercaptopropyltriethoxysilane (MPS) modified GO (MGO)/styrene-butadiene rubber (SBR) composites were prepared by a synergetic strategy of latex compounding method and thiol-ene click reaction. It was found that the mercapto groups in MGO reacted with the vinyl groups in SBR molecules through thiol-ene click reaction during the crosslinking process …

Β-Methylumbelliferone Surface Modification And Permeability Investigations At Pentel™ Graphite Electrodes, Susan Warren, Brian Seddon, Ruth Pilkington, Alison Crossely, Philip Holdway, Eithne Dempsey

Articles

Electrochemical and micro-imaging analysis of a commercial graphite-composite material is presented following electro-oxidation with β-methylumbelliferone. Charge-transfer surface modification was observed for the graphite electrode, presumed to have arisen from adsorbed interfacial umbelliferone moieties. The molecular permeability of the new surface towards a range of similar, yet size-variable (23 Å3–136 Å3) molecular redox probes is discussed. Red-shift fluorescence in confocal microscopy offers further support for the presence of a surface-bound umbelliferone layer. An SEM-platinum profiling technique was used as an imaging tool to map the umbelliferone surface and size-distribution of electroactive sites.

K-Means And Hierarchical Cluster Analysis As Segmentation Algorithms Of Ftir Hyperspectral Images Collected From Cutaneous Tissue, Cassio Lima, Luciana Correa, Hugh Byrne, Denise Zezell

Conference papers

Fourier Transform Infrared (FTIR) spectroscopy is a rapid and label-free analytical technique whose potential as a diagnostic tool has been well demonstrated. The combination of spectroscopy and microscopy technologies enable wide-field scanning of a sample, providing a hyperspectral image with tens of thousands of spectra in a few minutes. In order to increase the information content of FTIR images, different clustering algorithms have been proposed as segmentation methods. However, systematic comparative tests of these techniques are still missing. Thus, the present paper aims to compare the ability of K-means Cluster Analysis (KMCA) and Hierarchical Cluster Analysis (HCA) as clustering algorithms …

Diclofenac Determination Using Ceo2 Nanoparticle Modified Screen-Printed Electrodes:A Study Of Background Correction, Rafaela C. De Carvalho, Tony Betts, John Cassidy

Articles

The detection of low levels of drugs including Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) in natural waters and wastewaters is becoming increasingly important. Electrochemical methods offer an attractive means of detection, as they overcome many disadvantages associated with the currently available analytical methods. Cerium dioxide nanoparticles were synthesised and then incorporated onto the working electrodes of commercial graphite-based Screen Printed Carbon Electrodes (SPCE) then used to determine diclofenac levels. Following initial Cyclic Voltammetry studies, Square Wave Voltammetry (SWV) investigations were conducted over a range of conditions to optimise the peak potential separation and sensitivity of the method. The use of background correction …

Formation Of P-N Junctions In Nanoparticle Cerium Oxide Electrolytic Cells Displaying Memristive Switching Behaviour, Rafaela Cristina De Carvalho, Tony Betts, John Cassidy

Articles

A macro-scale metal–semiconductor–metal device comprising CeO₂ nanoparticles cast from a suspension of cerium dioxide formed by a novel synthetic method was fabricated. Thin CeO₂ films of 40 nm thickness placed between panels of aluminium and/or copper displayed memristive-like resistive switching behaviour upon the application of potential sweeps ranging between −0.6 V and 0.6 V. A mechanism is proposed based on the notion that an electrolytic cell operates under such conditions with the initial formation of p and n-type regions within the central semiconductive thin film. Evidence is presented for the existence of numerous point defects in these nanosized …

An Ammonia Sensor Using An Unadorned Bromocresol Layer, John Cassidy, Caoimhe Ní Néill, Merve Akdağ, Tony Betts

Articles

Bromocresol Purple,(BCP) cast onto an acetate sheet, was used to sense ammonia. This simple layer responded reversibly to a low concentration ( 15 ppm) of ammonia in the presence of water vapour. The BCP solution was spincoated on an acetate sheet from a solution in dichloromethane. This layer was exposed to nitrogen and NH3/H2O vapour in quick succession. The colour change occurred from yellow to purple rapidly in the solid state. The λmax for the neutral ( acid) form of the BCP was found to be 435 nm and the λmax for the dianion ( base form) of the BCP …

Determination Of Integrity, Stability And Density Of The Dna Layers Immobilised At Glassy Carbon And Gold Electrodes Using Ferrocyanide, John Colleran, Anna Banasiak

Articles

The technique chosen to immobilise DNA onto electrodes can determine the density and stability of the resultant immobilised layer. DNA‐modified electrodes were prepared using four common DNA immobilisation methods and characterised using ferrocyanide. The negatively charged DNA strands should repel ferrocyanide anions. The DNA layers created using adsorption at glassy carbon electrodes were unstable, while those created through chemisorption of thiol‐modified DNA onto gold electrodes were repeatable and stable, and returned, on average, 94 % repulsion of the probe. The presented results show how the immobilisation protocol, and DNA type, affects the stability, repeatability, and integrity of resultant DNA layers.

Structural Annotation Of Electro- And Photochemically Generated Transformation Products Of Moxidectin Using High-Resolution Mass Spectrometry, Lisa Kotthoff, Sarah-Louise O'Callaghan, Jan Lisec, Tanja Schwerdtle, Matthias Koch

Articles

Moxidectin (MOX) is a widely used anthelmintic drug for the treatment of internal and external parasites in food-producing and companion animals. Transformation products (TPs) of MOX, formed through metabolic degradation or acid hydrolysis, may pose a potential environmental risk, but only few were identified so far. In this study, we therefore systematically characterized electro- and photochemically generated MOX TPs using high-resolution mass spectrometry (HRMS). Oxidative electrochemical (EC) TPs were generated in an electrochemical reactor and photochemical (PC) TPs by irradiation with UV-C light. Subsequent HRMS measurements were performed to identify accurate masses and deduce occurring modification reactions of derived TPs …

September 2019 Therapeutic Delivery Update, Elaine Harris

Articles

No abstract provided.

Determination Of Upconversion Quantum Yields Using Charge-Transfer State Fluorescence Of Heavy-Atom-Free Sensitizer As A Self-Reference, Natalia Kiseleva, Dmitry Busko, Bryce Richards, Mikhail Filatov, Andrey Turshatov

Articles

The efficiency of photon upconversion via triplet–triplet annihilation is characterized by an upconversion quantum yield (Φ_UC); however, uncertainties remain for its determination. Here, we present a new approach for the relative measurement of Φ_UC for green-to-blue upconversion using BODIPY–pyrene donor–acceptor dyad (BD1) as a heavy-atom-free triplet sensitizer. This new approach exploits broad fluorescence from a charge-transfer (CT) state of BD1, which possesses (i) a significant Stokes shift of 181 nm in dichloromethane and (ii) a comparably high CT-fluorescence quantum yield (Φ_ref = 7.0 ± 0.2%), which is independent from oxygen presence and emitter (perylene) concentration while …

Cu(Ii) Phenanthroline-Phenazine Complexes Dysregulate Mitochondrial Function And Stimulate Apoptosis, Garret Rochford, Zara Molphy, Kevin Kavanagh, Malachy Mccann, Michael Devereux, Andrew Kellett, Orla L. Howe

Articles

Herein we report an in-depth study on the cytotoxic mechanism of action of four developmental cytotoxic copper(II) complexes: [Cu(phen)2]2+ (Cu-Phen); [Cu(DPQ)(Phen)]2+ (Cu-DPQ-Phen); [Cu(DPPZ)(Phen)]2+; and [Cu(DPPN)(Phen)]2+ (where Phen = 1,10-phenanthroline, DPQ = dipyrido[3,2-f:20,30-h]quinoxaline, DPPZ = dipyrido[3,2-a:20,30-c]phenazine, and DPPN = benzo[i]dipyrido[3,2-a:20,30-c]phenazine). This complex class is known for its DNA intercalative properties and recent evidence—derived from an in vivo proteomic study—supports the potential targeting of mitochondrial function. Therefore, we focused on mitochondrial-mediated apoptosis related to cytotoxic activity and the potential impact these agents have on mitochondrial function. The Cu(II) complexes demonstrated superior activity regardless of aromatic extension within the phenazine ligand to the …

2-(Di­Phenyl­Methyl­Idene)-2,3-Di­Hydro-1h-Inden-1-One, Tao Zhang, Vilmar Bandero, Tom Mccabe, Neil Frankish, Helen Sheridan

Articles

In the title mol­ecule, C₂₂H₁₆O, the indanone ring system is approximately planar with a dihedral angle between the fused rings of 5.13 (14)°. Two benzene rings are linked together at one side of a double bond, sitting on either side of the indanone ring system and making dihedral angles of 70.30 (12) and 44.74 (13)° with it. In the crystal, hydrogen bonding is not present, but weak C—H⋯π or π–π inter­actions occur and mol­ecules form a sheet-like structure in the bc plane.