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Articles 121 - 150 of 241

Full-Text Articles in Chemistry

A Fast Linear Electro-Optical Effect In A Non-Chiral Bent-Core Liquid Crystal, Yuri Panarin, S.P. Sreenilayam, J.K. Vij, A. Lehmann, C. Tschierske Jan 2017

A Fast Linear Electro-Optical Effect In A Non-Chiral Bent-Core Liquid Crystal, Yuri Panarin, S.P. Sreenilayam, J.K. Vij, A. Lehmann, C. Tschierske

Articles

We report the observation of an electro-optical effect for a linear rotation of the optical axis as function of the electric field in an achiral tilted bent-core liquid crystalline compound, in which 4-cyanoresorcinol bisbenzoate core is symmetrically terminated by long linear alkyl chains (n =16) on both ends. The linear electro-optic effect observed in this material is similar to the deformed helical ferroelectric liquid crystal (DHFLC) effect reported previously in a FLC material except that dimensions of the helical pitch differ by two orders of magnitude. In the chiral systems, the helical pitch usually lies on the scale of sub-optical …


Thermostability Of The Coating, Antigen And Immunostimulator In An Adjuvanted Oral Capsule Vaccine Formulation, Stephanie Longet, Vincenzo Aversa, Daire O'Donnell, Joshua Tobias, Monica Rosa, Jan Holmgren, Ivan Coulter, Ed Lavelle Jan 2017

Thermostability Of The Coating, Antigen And Immunostimulator In An Adjuvanted Oral Capsule Vaccine Formulation, Stephanie Longet, Vincenzo Aversa, Daire O'Donnell, Joshua Tobias, Monica Rosa, Jan Holmgren, Ivan Coulter, Ed Lavelle

Articles

Oral vaccines present an attractive alternative to injectable vaccines for enteric diseases due to ease of delivery and the induction of intestinal immunity at the site of infection. However, susceptibility to gastrointestinal proteolysis, limited transepithelial uptake and a lack of clinically acceptable adjuvants present significant challenges. A further challenge to mass vaccination in developing countries is the very expensive requirement to maintain the cold chain. We recently described the effectiveness of a Single Multiple Pill® (SmPill®) adjuvanted capsule approach to enhance the effectiveness of a candidate enterotoxigenic Escherichia coli (ETEC) oral vaccine. Here it was demonstrated that this delivery system …


The Antibacterial Activity Of Metal Complexes Containing 1, 10-Phenanthroline: Potential As Alternatire Therapeutics In The Era Of Antibiotic Resistance, Livia Viganon, Orla L. Howe, Pauraic Mccarron, Malachy Mccann, Michael Devereux Jan 2017

The Antibacterial Activity Of Metal Complexes Containing 1, 10-Phenanthroline: Potential As Alternatire Therapeutics In The Era Of Antibiotic Resistance, Livia Viganon, Orla L. Howe, Pauraic Mccarron, Malachy Mccann, Michael Devereux

Articles

The “antibiotic era”, characterized by the overuse and misuse of antibiotics, over the last half-century has culminated in the present critical “era of resistance”. The treatment of bacterial infections is challenging because of a decline in the current arsenal of useful antibiotics and the slow rate of new drug development. The discovery of a new gene (mcr-1) in 2015, which enables bacteria to be highly resistant to polymyxins (such as colistin), the last line of antibiotic defence left, heralds a new level of concern as this gene is susceptible to horizontal gene transfer, with alarming potential to be spread between …


Graphene Toxicity As A Double-Edged Sword Of Risks And Exploitable Opportunities: A Critical Analysis Of The Most Recent Trends And Developments, Yuri Volkov, Jennifer Mcintyre, Adriele Prina-Mello Jan 2017

Graphene Toxicity As A Double-Edged Sword Of Risks And Exploitable Opportunities: A Critical Analysis Of The Most Recent Trends And Developments, Yuri Volkov, Jennifer Mcintyre, Adriele Prina-Mello

Articles

Increased production volumes and a broadening application spectrum of graphene have raised concerns about its potential adverse effects on human health. Numerous reports demonstrate that graphene irrespective of its particular form exerts its effects on a widest range of living organisms, including prokaryotic bacteria and viruses, plants, micro-and macro-invertebrates, mammalian and human cells and whole animals in vivo. However, the available experimental data is frequently a matter of significant divergence and even controversy. Therefore, we provide here a critical analysis of the most recent (2015-2016) reports accumulated in the graphene-related materials biocompatibility and toxicology field in order to elucidate the …


Correlation Between The Structure And The Anticorrosion Barrier Properties Of Hybrid Sol–Gel Coatings: Application To The Protection Of Aa2024-T3 Alloys, Maikki Cullen, Muhammad Morshed, Mary O'Sullivan, Emma Mchugh, Brendan Duffy, Mohamed Oubaha Jan 2017

Correlation Between The Structure And The Anticorrosion Barrier Properties Of Hybrid Sol–Gel Coatings: Application To The Protection Of Aa2024-T3 Alloys, Maikki Cullen, Muhammad Morshed, Mary O'Sullivan, Emma Mchugh, Brendan Duffy, Mohamed Oubaha

Articles

Hybrid sol–gel materials have been extensively studied as viable alternatives to toxic chromate (VI)-based coatings for the corrosion protection of AA2024-T3 in the aerospace industry, due to the wide range of available chemistries they offer and the tremendous development potential of innovative functional coatings. However, so far, little work has been performed in identifying the effect of the employed chemistries on the structure and anticorrosion properties of the coatings. This work proposes to contribute to a better understanding of the relationship existing between the structure, morphology and anticorrosion properties of hybrid sol–gel coatings deposited on AA2024- T3 aluminium surfaces, the …


Extraction And Quantification Of Sinapinic Acid From Irish Rapeseed Meal And Assessment Of Angiotensin-I Converting Enzyme (Ace-I) Inhibitory Activity, Leah Quinn, Steven Gray, Steve Meaney, Stephen Finn, Padraig Mcloughlin, Maria Hayes Jan 2017

Extraction And Quantification Of Sinapinic Acid From Irish Rapeseed Meal And Assessment Of Angiotensin-I Converting Enzyme (Ace-I) Inhibitory Activity, Leah Quinn, Steven Gray, Steve Meaney, Stephen Finn, Padraig Mcloughlin, Maria Hayes

Articles

Phenolic compounds, including phenolic acids, are known to play a protective role against the development of cardiovascular disease. The aim of this work was to generate a phenolic acid extract from Irish rapeseed meal, to determine the quantity of sinapinic acid (SA) in this fraction and to assess the ability of this fraction to inhibit the enzyme angiotensin-I converting enzyme (ACE-I; EC 3.4.15.1). A crude phenolic extract (fraction 1), free phenolic acid containing extract (fraction 2), and an extract containing phenolic acids liberated from esters (fraction 3) were generated from Irish rapeseed meal using a methanol:acetone:water solvent mixture (7:7:6). The …


Feasibility Of Laser-Induced Breakdown Spectroscopy (Libs) As An At-Line Validation Tool For Calcium Determination In Infant Formula, Xavier Cama-Moncunill, Maria Markiewicz-Keszycka, Yash Dixit, Raquel Cama-Moncunill, Maria Piedad Casado-Gavalda, Patrick J. Cullen, Carl Sullivan Jan 2017

Feasibility Of Laser-Induced Breakdown Spectroscopy (Libs) As An At-Line Validation Tool For Calcium Determination In Infant Formula, Xavier Cama-Moncunill, Maria Markiewicz-Keszycka, Yash Dixit, Raquel Cama-Moncunill, Maria Piedad Casado-Gavalda, Patrick J. Cullen, Carl Sullivan

Articles

In this study, a 150 mJ laser-induced breakdown spectroscopy (LIBS) system was assessed to determine calcium content in infant formula (IF) samples. LIBS is a promising emission spectroscopic technique for elemental analysis, which offers advantages over conventional methods such as real-time analyses, little to no sample preparation and ease of use. The aim of this work was to evaluate the feasibility of LIBS as an at-line tool for IF manufacturing. To this end, IF mixtures with varying content of calcium were prepared over a range (approx. 1.5–7 mg/g of calcium) selected to be in conformity with the guidelines provided by …


Biofunctionalized Capillary Flow Channel Platform Integrated With 3d Nanostructured Matrix To Capture Circulating Tumor Cells, Shashwat Banerjee, Ganesh Khutale, Vrushali Khobragade, Narendra Kale, Milind Pore, Govind Chate, Archana Jalota-Badhwar, Manoj Dongare, Jayant Khandare Jan 2017

Biofunctionalized Capillary Flow Channel Platform Integrated With 3d Nanostructured Matrix To Capture Circulating Tumor Cells, Shashwat Banerjee, Ganesh Khutale, Vrushali Khobragade, Narendra Kale, Milind Pore, Govind Chate, Archana Jalota-Badhwar, Manoj Dongare, Jayant Khandare

Articles

Circulating tumor cells (CTCs) from peripheral blood account genetic information for cancer diagnosis and overall disease monitoring. Analysis of “liquid biopsy” holds immense promise as it may lead to new approaches for cancer treatment. The study reports effective and continuous flow microchannel system for isolating CTCs using transferrin conjugated 3D matrix synthesized by crosslinking polyethylene glycol-Fe3O4 nanostructures for rapid and efficient capturing of CTCs. The platform provides option of using multiple microchannel units in series that can influence higher cell-capture efficiency due to increasing cell-substrate contact frequency. CTCs are captured with high efficiency even at low concentration of target cells …


The Potential Of Atmospheric Air Cold Plasma For Control Of Bacterial Contaminants Relevant To Cereal Grain Production, Agata Los, Dana Ziuzina, Daniela Boehm, Patrick J. Cullen, Paula Bourke Jan 2017

The Potential Of Atmospheric Air Cold Plasma For Control Of Bacterial Contaminants Relevant To Cereal Grain Production, Agata Los, Dana Ziuzina, Daniela Boehm, Patrick J. Cullen, Paula Bourke

Articles

The aim of this work was to investigate the efficacy of dielectric barrier discharge atmospheric cold plasma (DBD ACP) against bacteria associated with grains quality and safety. ACP inactivation efficacy was tested against biofilms formed by different strains of E. coli, Bacillus and Lactobacillus in grain model media and against B. atrophaeus endospores either in grain media or attached on abiotic surfaces. Effects were dependent on bacterial strain, media composition and mode of ACP exposure. ACP treatment for 5min reduced E. coli spp., B. subtilis and Lactobacillus spp. biofilms by >3 log10, whereas insignificant reductions were achieved for B. atrophaeus. …


Impact Of Atmospheric Pressure Nonequilibrium Plasma Discharge On Polymer Surface Metrology, Laurence Scally, James Lalor, Patrick J. Cullen, Vladimir Milosavljevic Jan 2017

Impact Of Atmospheric Pressure Nonequilibrium Plasma Discharge On Polymer Surface Metrology, Laurence Scally, James Lalor, Patrick J. Cullen, Vladimir Milosavljevic

Articles

Due to the attraction of plasma technologies as a clean and efficient means of surface modification, significant research has gone into the physical and chemical aspects of polymer functionalization. In this study, it was shown that the use of an atmospheric plasma jet can efficiently modify the surface of polyethylene terephthalate samples and change their hydrophobic properties to more hydrophilic characteristics. The dependence on the changes with respect to time, distance, and atomic oxygen (O I) intensity were considered as factors. It was found that with closer proximity to the plasma source (without causing thermal degradation) and with increasing levels …


Evaluation Of Chemical Immersion Treatments To Reduce Microbial Populations In Fresh Beef, Ahmed Kassem, Joseph Meade, James Gibbons, Kevina Mcgill, Ciara Walsh, James Lyng, Paul Whyte Jan 2017

Evaluation Of Chemical Immersion Treatments To Reduce Microbial Populations In Fresh Beef, Ahmed Kassem, Joseph Meade, James Gibbons, Kevina Mcgill, Ciara Walsh, James Lyng, Paul Whyte

Articles

The aim of the current study was to assess the ability of a number of chemicals (acetic Acid (AA), citric acid (CA) lactic acid (LA), sodium decanoate (SD) and trisodium phosphate (TSP)) to reduce microbial populations (total viable count, Campylobacter jejuni, Escherichia coli, Salmonella typhimurium and Listeria monocytogenes) on raw beef using an immersion system. The following concentrations of each chemical were used: 3 & 5% for AA, CA, LA, SD and 10 & 12% for TSP. Possible synergistic effects of using combinations of two chemicals sequentially (LA +CA and LA +AA) were also investigated. L*, a* and b* values …


Synthesis Of Orthogonally Protected Thioamide Dipeptides For Use In Solid-Phase Peptide Synthesis, Fintan Kelleher, Kim Manzor Nov 2016

Synthesis Of Orthogonally Protected Thioamide Dipeptides For Use In Solid-Phase Peptide Synthesis, Fintan Kelleher, Kim Manzor

Articles

Orthogonally protected thioamide-containing dipeptides were efficiently and cleanly prepared from the precursor dipeptides using Curphey’s method (P4S10, hexamethyldisiloxane (HMDO), reflux, DCM) in 67-96% isolated yield. This was in contrast to the use of Lawesson’s or Berzelius’ reagents where significant issues with reaction non-completion, decomposition and purification were observed. Subsequent clean removal of the dipeptides’ t-butyl ester protecting groups gave thioamide dipeptide acids which were suitable for use in solid-phase peptide synthesis (SPPS).


Screening The Low Molecular Weight Fraction Of Human Serum Using Atr-Ir Spectroscopy, Franck Bonnier, Matthew J. Baker, Hugh Byrne Jun 2016

Screening The Low Molecular Weight Fraction Of Human Serum Using Atr-Ir Spectroscopy, Franck Bonnier, Matthew J. Baker, Hugh Byrne

Articles

Vibrational spectroscopic techniques can detect small variations in molecular content, linked with disease, showing promise for screening and early diagnosis. Biological fluids, particularly blood serum, are potentially valuable for diagnosis purposes. The so-called Low Molecular Weight Fraction (LMWF) contains the associated peptidome and metabolome and has been identified as potentially the most relevant molecular population for disease-associated biomarker research. Although vibrational spectroscopy can deliver a specific chemical fingerprint of the samples, the High Molecular Weight Fraction (HMWF), composed of the most abundant serum proteins, strongly dominates the response and ultimately makes the detection of minor spectral variations a challenging task. …


The Evaluation And Implementation Of Magnetic Fields For Large Strain Uniaxial And Biaxial Cyclic Testing Of Magnetorheological Elastomers., Dave Gorman, Niall Murphy, Ray Ekins, Stephen Jerrams May 2016

The Evaluation And Implementation Of Magnetic Fields For Large Strain Uniaxial And Biaxial Cyclic Testing Of Magnetorheological Elastomers., Dave Gorman, Niall Murphy, Ray Ekins, Stephen Jerrams

Articles

Magnetorheological Elastomers (MREs) are “smart” materials whose physical properties are altered by the application of magnetic fields. In previous studies the properties of MREs have been evaluated under a variety of conditions, however little attention has been paid to the recording and reporting of the magnetic fields used in these tests [1]. Currently there is no standard accepted method for specifying the magnetic field applied during MRE testing. This study presents a detailed map of a magnetic field applied during MRE tests as well as providing the first comparative results for uniaxial and biaxial testing under high strain fatigue test …


Photocatalytic Properties Of G-C3n4–Tio2 Heterojunctions Under Uv And Visible Light Conditions, Rachel Fagan, Declan Mccormack, Steven J. Hinder, Suresh Pillai Apr 2016

Photocatalytic Properties Of G-C3n4–Tio2 Heterojunctions Under Uv And Visible Light Conditions, Rachel Fagan, Declan Mccormack, Steven J. Hinder, Suresh Pillai

Articles

Graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2) were chosen as a model system to investigate photocatalytic abilities of heterojunction system under UV and visible light conditions. The use of g-C3N4 has been shown to be effective in the reduction in recombination through the interaction between the two interfaces of TiO2 andg-C3N4. A simple method of preparing g-C3N4 through the pyrolysis of melamine was employed, which was then added to undoped TiO2 material to form the g-C3N4–TiO2 system. These materials were then fully characterized by X-ray diffraction (XRD), Brunauer Emmett Teller (BET), and various spectroscopic techniques including Raman, X-ray photoelectron …


Novel Mitochondrial Complex I Inhibitors Restore Glucose-Handling Abilities Of High-Fat Fed Mice, Darren Martin, Siobhan Leonard, Robert Devine, Clara Redondo, Gemma Kinsella, Conor Breen, Victoria Mceneaney, Mary Rooney, Tim Munsey, Richard Porter, Asipu Sivaprasadarao, John Stephens, John Findlay Apr 2016

Novel Mitochondrial Complex I Inhibitors Restore Glucose-Handling Abilities Of High-Fat Fed Mice, Darren Martin, Siobhan Leonard, Robert Devine, Clara Redondo, Gemma Kinsella, Conor Breen, Victoria Mceneaney, Mary Rooney, Tim Munsey, Richard Porter, Asipu Sivaprasadarao, John Stephens, John Findlay

Articles

Metformin is the main drug of choice for treating type 2 diabetes, yet the therapeutic regimens and side effects of the compound are all undesirable and can lead to reduced compliance. The aim of this study was to elucidate the mechanism of action of two novel compounds which improved glucose handling and weight gain in mice on a high-fat diet. Wildtype C57Bl/6 male mice were fed on a high-fat diet and treated with novel, anti-diabetic compounds. Both compounds restored the glucose handling ability of these mice. At a cellular level, these compounds achieve this by inhibiting complex I activity in …


An Effective Method For The Preparation Of High Temperature Stable Anatase Tio2 Photocatalysts, Rachel Fagan, Declan Mccormack, Suresh Pillai, Damian Synnott Mar 2016

An Effective Method For The Preparation Of High Temperature Stable Anatase Tio2 Photocatalysts, Rachel Fagan, Declan Mccormack, Suresh Pillai, Damian Synnott

Articles

An efficient, rapid and straightforward method for the preparation of nitrogen and fluorine (N, F) codoped high temperature stable anatase using a microwave pre-treatment is reported. Using a single source, ammonium fluoride (NH4F) for both nitrogen and fluorine, effective doping of the precursor titanium isopropoxide (TTIP) was possible. These samples were characterised for their structural and optical properties using X-ray diffraction (XRD), Fourier transform IR (FTIR), Raman spectroscopy and UV-vis spectroscopy. In terms of the anatase to rutile transition enhancement using a novel microwave assisted technique, the sample prepared in a composition of 1:8 TiO2: NH …


Structural Dependence Of The In Vitro Cytotoxicity, Oxidative Stress And Uptake Mechanisms Of Poly(Propylene Imine) Dendritic Nanoparticles, Humza Khalid, Sourav Prasanna Mukherjee, Luke O'Neill, Hugh Byrne Feb 2016

Structural Dependence Of The In Vitro Cytotoxicity, Oxidative Stress And Uptake Mechanisms Of Poly(Propylene Imine) Dendritic Nanoparticles, Humza Khalid, Sourav Prasanna Mukherjee, Luke O'Neill, Hugh Byrne

Articles

The in vitro cytotoxic and intracellular oxidative stress responses to exposure to poly (propylene imine) (PPI) dendritic nanoparticles of increasing generation (number of repeated branching cycles) (G0-G4) were assessed in an immortal non-cancerous human keratinocyte cell-line (HaCaT). Confocal fluorescence microscopy with organelle staining was used to explore the uptake and intracellular trafficking mechanisms. A generation and dose dependent cytotoxic response was observed, increasing according to generation and therefore number of surface amino groups. A comparison of the cytotoxic response of G4 PPI and the related G4 Poly (amido amine) dendrimer indicates that the PPI with the same number of surface …


Enhanced Corrosion Protection And Biocompatibility Of A Plga-Silane Coating On Az31 Mg Alloy For Orthopaedic Applications, Sankalp Agarwal, Muhammad Morshed, Marie-Noelle Labour, David Hoey, Brendan Duffy, James Curtin, Swarna Jaiswal Jan 2016

Enhanced Corrosion Protection And Biocompatibility Of A Plga-Silane Coating On Az31 Mg Alloy For Orthopaedic Applications, Sankalp Agarwal, Muhammad Morshed, Marie-Noelle Labour, David Hoey, Brendan Duffy, James Curtin, Swarna Jaiswal

Articles

This paper reports a multi-step procedure to fabricate a novel corrosion resistant and biocompatible PLGA-silane coating on the magnesium (Mg) alloy AZ31. The first step involves alkaline passivation followed by dip coating in a methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) mixture to produce a cross-linked siloxane coating. The second step is to impart an amine functionalization to the silane modified surface by using 3-aminopropyl-triethoxy silane (APTES) for promoting adhesion of the acid terminated poly-(lactic-co-glycolic) acid (PLGA) as a final coating step. Static contact angle measurements, Fourier transform infrared spectroscopy and scanning electron microscopy analysis confirmed the successful assembly of coatings on …


Investigating Alaskan Methane And Carbon Dioxide Fluxes Using Measurements From The Carve Tower, Anna Karion, Colm Sweeney Colm Sweeney, John B. Miller John B. Miller, Arlyn E. Andrews, Roisin Commane, Steven Dinardo, John M. Henderson, Jacob Lindaas, John C. Lin, Kristina Luus, Tim Newberger, Pieter Tans Pieter Tans, Steven C. Wofsy, Sonja Wolter, Charles E. Miller Jan 2016

Investigating Alaskan Methane And Carbon Dioxide Fluxes Using Measurements From The Carve Tower, Anna Karion, Colm Sweeney Colm Sweeney, John B. Miller John B. Miller, Arlyn E. Andrews, Roisin Commane, Steven Dinardo, John M. Henderson, Jacob Lindaas, John C. Lin, Kristina Luus, Tim Newberger, Pieter Tans Pieter Tans, Steven C. Wofsy, Sonja Wolter, Charles E. Miller

Articles

Northern high-latitude carbon sources and sinks, including those resulting from degrading permafrost, are thought to be sensitive to the rapidly warming climate. Because the near-surface atmosphere integrates surface fluxes over large ( ∼ 500–1000 km) scales, atmospheric monitoring of carbon dioxide (CO2) and methane (CH4) mole fractions in the daytime mixed layer is a promising method for detecting change in the carbon cycle throughout boreal Alaska. Here we use CO2 and CH4 measurements from a NOAA tower 17 km north of Fairbanks, AK, established as part of NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE), to investigate regional fluxes of …


New Approach Of Modifying The Anatase To Rutile Transition Temperature In Tio2 Photocatalysts, Ciara Byrne, Rachel Fagan, Steven Hinder, Declan Mccormack, Suresh Pillai Jan 2016

New Approach Of Modifying The Anatase To Rutile Transition Temperature In Tio2 Photocatalysts, Ciara Byrne, Rachel Fagan, Steven Hinder, Declan Mccormack, Suresh Pillai

Articles

In pure synthetic titanium dioxide, the anatase to rutile phase transition usually occurs between the temperatures of 600 °C and 700 °C. The phase transition temperature can be altered by various methods, including modifying the precursor or by adding dopant or modifier to the TiO2 sample. In an attempt to investigate the phase transition using aromatic carboxylic acids, the current study examines the impact of increasing concentrations of benzoic acid (1 : 0, 1 : 1, 1 : 4 and 1 : 8 molar ratio TiO2 : benzoic acid) on anatase to rutile transition. The samples were characterised using Raman …


Improved High Temperature Stability Of Anatase Tio2 Photocatalysts By N, F, P Co-Doping, Rachel Fagan, Declan Mccormack, Steven Hinder, Suresh Pillai Jan 2016

Improved High Temperature Stability Of Anatase Tio2 Photocatalysts By N, F, P Co-Doping, Rachel Fagan, Declan Mccormack, Steven Hinder, Suresh Pillai

Articles

Among the three commonly occurring phases (anatase, rutile, and brookite) of TiO2, the anatase form is reported to be the best photocatalyst due to the improved charge-carrier mobility and the greater number of surface hydroxyl groups. The anatase to rutile transition in titania photocatalysts usually occurs at a temperature between 500 °C to 700 °C. Development of a high temperature stable (above 1000 °C) anatase phase is important for various environmental applications (e.g. self-cleaning ceramic tiles, anti-microbial sanitary wares, etc.). In this study, the use of ammonium hexafluorophosphate as a single source dopant (method A) and urea, trifluoroacetic acid and …


Optimisation Of Anodic Oxidation Of Aluminium For Enhanced Adhesion And Corrosion Properties Of Sol-Gel Coatings., Michael Whelan, Tobin Edmond, John Cassidy, John Colreavy, Brendan Duffy Jan 2016

Optimisation Of Anodic Oxidation Of Aluminium For Enhanced Adhesion And Corrosion Properties Of Sol-Gel Coatings., Michael Whelan, Tobin Edmond, John Cassidy, John Colreavy, Brendan Duffy

Articles

The anodising process for clad and bare AA2024-T3 has been optimised as a surface preparation technique prior to sol-gel coating deposition. The combination of anodised aluminium surfaces and organically functionalised sol-gel chemistry have been investigated to impart elevated corrosion resistance and increased mechanical properties to the aluminium metal. A duplex anodising process has been developed to utilise the natural corrosion resistance properties of sulphuric acid anodising with the adhesion and hosting properties of phosphoric acid anodising. The novel anodising process and sol-gel sealed surfaces have been characterised using field emission scanning electron microscopy, energy dispersive x-ray spectroscopy. Performance of the …


Characterization Of Dielectric Barrier Discharge Atmospheric Air Plasma Treated Chitosan Films, Shashi Pankaj, Carmen Bueno-Ferrer, Luke O'Neill, B.K. Tiwari, Paula Bourke, Patrick J. Cullen Jan 2016

Characterization Of Dielectric Barrier Discharge Atmospheric Air Plasma Treated Chitosan Films, Shashi Pankaj, Carmen Bueno-Ferrer, Luke O'Neill, B.K. Tiwari, Paula Bourke, Patrick J. Cullen

Articles

Dielectric barrier discharge (DBD) plasma is a novel non-thermal food decontamination technology. The effects of DBD plasma on the surface topography, chemical composition and crystal structure, film hydrophilicity, water vapor permeability and oxygen permeability of chitosan films have been examined. DBD plasma treatment increased the surface roughness of chitosan films with emergence of sharp protuberances. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy spectra confirm a significant increase in the oxygen containing groups in the chitosan film after plasma treatment. Significant increase in the film hydrophilicity was observed after plasma treatment. X-ray diffraction results showed that DBD plasma treatment do …


Spontaneous Helix Formation In Non-Chiral Bent-Core Liquid Crystals With Fast Linear Electro-Optic Effect, Sithara P. Sreenilayam, Yuri Panarin, Jagdish K. Vij, Vitaly P. Panov, Anne Lehmann, Marco Poppe, Marko Prehm, Carsten Tschierske Carsten Tschierske Jan 2016

Spontaneous Helix Formation In Non-Chiral Bent-Core Liquid Crystals With Fast Linear Electro-Optic Effect, Sithara P. Sreenilayam, Yuri Panarin, Jagdish K. Vij, Vitaly P. Panov, Anne Lehmann, Marco Poppe, Marko Prehm, Carsten Tschierske Carsten Tschierske

Articles

Liquid crystals (LCs) represent one of the foundations of modern communication and photonic technologies. Present display technologies are based mainly on nematic LCs, which suffer from limited response time for use in active colour sequential displays and limited image grey scale. Herein we report the first observation of a spontaneously formed helix in a polar tilted smectic LC phase (SmC phase) of achiral bent-core (BC) molecules with the axis of helix lying parallel to the layer normal and a pitch much shorter than the optical wavelength. This new phase shows fast (∼30 μs) grey-scale switching due to the deformation of …


Bis(Spirolactam) 1,3-Double-Armed Calix[4]Arene Compounds And Their Application As Extractants For The Determination Of Heavy Metal Ions, Fintan Kelleher, Mary Deasy, James Ward, Li Li, Fiona Regan Oct 2015

Bis(Spirolactam) 1,3-Double-Armed Calix[4]Arene Compounds And Their Application As Extractants For The Determination Of Heavy Metal Ions, Fintan Kelleher, Mary Deasy, James Ward, Li Li, Fiona Regan

Articles

A number of double-armed calix[4]arene compounds, with proline-derived spirolactam ligating groups on the lower rim, have been synthesised and investigated as extractants of toxic heavy metal ions from aqueous solution. Pedersen’s extraction technique was employed to determine the capability of these new 1,3-distal derived calix[4]arene spiroalactams to extract selected heavy metal ions (e.g. Pb2+, Cd2+, Zn2+, Cu2+, Ni2+, Co2+) from an aqueous phase into an organic phase. The percentage extraction was calculated using UV-vis spectroscopy. All of the compounds synthesised demonstrated good selectivity for the heavy metals selected …


Determination Of The Polymerisation Rate Of A Low-Toxicity Diacetone Acrylamide-Based Holographic Photopolymer Using Raman Spectroscopy, Dervil Cody, Emilia Mihaylova, Luke O'Neill, Izabela Naydenova Oct 2015

Determination Of The Polymerisation Rate Of A Low-Toxicity Diacetone Acrylamide-Based Holographic Photopolymer Using Raman Spectroscopy, Dervil Cody, Emilia Mihaylova, Luke O'Neill, Izabela Naydenova

Articles

The polymerisation rate of a low-toxicity Diacetone Acrylamide (DA)-based photopolymer has been measured for the first time using Raman spectroscopy. A value for the polymerisation rate of 0.020 s−1 has been obtained for the DA photopolymer by modelling the polymerisation reaction dynamics as a stretched exponential or Kohlrausch decay function. This is significantly lower than the polymerisation rate of 0.100 s−1 measured for the well known Acrylamide (AA)-based photopolymer composition. The effect of the additive glycerol on the polymerisation rate of the DA-based photopolymer has also been investigated. The inclusion of glycerol is observed to increase the rate …


Studies On The Synthesis Of Orthogonally Protected Azalanthionines, And Of Routes Towards B-Methyl Azalanthionines, By Ring-Opening Of N-Activated Aziridine-2-Crboxylates, Keith O'Brien, Keith Ó Proinsias, Fintan Kelleher Jun 2014

Studies On The Synthesis Of Orthogonally Protected Azalanthionines, And Of Routes Towards B-Methyl Azalanthionines, By Ring-Opening Of N-Activated Aziridine-2-Crboxylates, Keith O'Brien, Keith Ó Proinsias, Fintan Kelleher

Articles

Orthogonally protected azalanthionines were successfully synthesised by the ring-opening of N-activated aziridine-2-carboxylates with protected diaminopropanoic acids (DAPs). The required DAPs were also prepared by ring-opening of N-activated aziridine-2-carboxylates with para-methoxybenzylamine, but it was found that the choice of aziridine protecting groups dictated both the success of the reaction as well as the regioselectivity of the isolated products. Attempts to extend the methodology to the preparation of the more sterically demanding b-methyl azalanthionines have, so far, been unsuccessful.


Metal-Organic Frameworks Based On Pyridyl-Tetrazole Ligands Containing Ester Or Carboxylate Pendant Arms, Ursula Sheridan, John Gallagher, Morten Bjerrum, Adrienne Fleming, Fintan Kelleher, John Mcginley May 2014

Metal-Organic Frameworks Based On Pyridyl-Tetrazole Ligands Containing Ester Or Carboxylate Pendant Arms, Ursula Sheridan, John Gallagher, Morten Bjerrum, Adrienne Fleming, Fintan Kelleher, John Mcginley

Articles

The coordination of pyridyl-tetrazole derivatives containing ester substituents, at either the N-1 or N-2 position of the tetrazole ring, with copper(II) chloride results in the formation of either 1:1 or 1:2 copper to ligand complexes, depending on the ligand. However, when the ester functionality is changed to a carboxylate group, the resulting complexation reactions yield metal-organic frameworks. The resulting structures vary dramatically in pore size, depending on both reaction solvents and position of carboxylate group on the tetrazole ring. Despite the presence of sodium cations in the reaction mixtures, no sodium incorporation was ever observed in any of the complexes. …


Selection Of The Process Parameters For The Mass Plating Of Discrete Electronic Components, Ann Hopper May 2014

Selection Of The Process Parameters For The Mass Plating Of Discrete Electronic Components, Ann Hopper

Articles

The miniaturisation of electronic components coupled with requirements for high temperature lead free soldering has forced the improvement of the termination finish of surface mount components to meet the critical demands of the electronic industry. In the present work the processing parameters necessary to plate miniature multilayer varistors (MLV’s) have been explored. The tooling selected was a “Rotary flow-thru’ plater” which achieved high volume plating with