43 results on '"Parmenter, Christopher D.J."'
Search Results
2. Biomaterial modification of urinary catheters with antimicrobials to give long-term broadspectrum antibiofilm activity
- Author
-
Fisher, Leanne E., Hook, Andrew L., Ashraf, Waheed, Yousef, Anfal, Barrett, David A., Scurr, David J., Chen, Xinyong, Smith, Emily F., Fay, Michael, Parmenter, Christopher D.J., Parkinson, Richard, and Bayston, Roger
- Published
- 2015
- Full Text
- View/download PDF
3. Kerogen nanoscale structure and CO2 adsorption in shale micropores
- Author
-
Gonciaruk, Aleksandra, Hall, Matthew R., Fay, Michael W., Parmenter, Christopher D.J., Vane, Christopher H., Klobystov, Andrei N., Ripepi, Nino, Gonciaruk, Aleksandra, Hall, Matthew R., Fay, Michael W., Parmenter, Christopher D.J., Vane, Christopher H., Klobystov, Andrei N., and Ripepi, Nino
- Abstract
Gas storage and recovery processes in shales critically depend on nano-scale porosity and chemical composition, but information about the nanoscale pore geometry and connectivity of kerogen, insoluble organic shale matter, is largely unavailable. Using adsorption microcalorimetry, we show that once strong adsorption sites within nanoscale network are taken, gas adsorption even at very low pressure is governed by pore width rather than chemical composition. A combination of focused ion beam with scanning electron microscopy and transmission electron microscopy reveal the nanoscale structure of kerogen includes not only the ubiquitous amorphous phase but also highly graphitized sheets, fiber- and onion-like structures creating nanoscale voids accessible for gas sorption. Nanoscale structures bridge the current gap between molecular size and macropore scale in existing models for kerogen, thus allowing accurate prediction of gas sorption, storage and diffusion properties in shales.
- Published
- 2021
4. Room temperature uniaxial magnetic anisotropy induced by Fe-islands in the InSe semiconductor van der Waals crystal
- Author
-
Moro, Fabrizio, Bhuiyan, Mahabub A., Kudrynskyi, Zakhar R., Puttock, Robert, Kazakova, Olga, Makarovsky, Oleg, Fay, Michael, Parmenter, Christopher D.J., Kovalyuk, Zakhar D., Fielding, Alistair John, Kern, Michal, and van Slageren, Joris
- Subjects
Condensed Matter::Materials Science ,InSe ,Iron ,Electron Spin Resonance (ESR) ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,van der Waals semiconductor ,Magnetic anisotropy - Abstract
The controlled manipulation of the spin and charge of electrons in a semiconductor has the potential to create new routes to digital electronics beyond Moore’s law, spintronics, and quantum detection and imaging for sensing applications. These technologies require a shift from traditional semiconducting and magnetic nanostructured materials. Here, a new material system is reported, which comprises the InSe semiconductor van der Waals crystal that embeds ferromagnetic Fe-islands. In contrast to many traditional semiconductors, the electronic properties of InSe are largely preserved after the incorporation of Fe. Also, this system exhibits ferromagnetic resonances and a large uniaxial magnetic anisotropy at room temperature, offering opportunities for the development of functional devices that integrate magnetic and semiconducting properties within the same material system.
- Published
- 2018
5. Additive manufacture of complex 3D Au-containing nanocomposites by simultaneous two-photon polymerisation and photoreduction
- Author
-
Hu, Qin, Sun, Xue Zhong, Parmenter, Christopher D.J., Fay, Michael W., Smith, Emily F., Rance, Graham A., He, Yinfeng, Zhang, Fan, Liu, Yaan, Irvine, Derek, Tuck, Christopher, Hague, Richard, Wildman, Ricky, and Parmenter, Christopher D. J.
- Abstract
© 2017 The Author(s). The fabrication of complex three-dimensional gold-containing nanocomposite structures by simultaneous two-photon polymerisation and photoreduction is demonstrated. Increased salt delivers reduced feature sizes down to line widths as small as 78 nm, a level of structural intricacy that represents a significant advance in fabrication complexity. The development of a general methodology to efficiently mix pentaerythritol triacrylate (PETA) with gold chloride hydrate (HAuCl4-3H2O) is reported, where the gold salt concentration is adjustable on demand from zero to 20 wt%. For the first-time 7-Diethylamino-3-thenoylcoumarin (DETC) is used as the photoinitiator. Only 0.5 wt% of DETC was required to promote both polymerisation and photoreduction of up to 20 wt% of gold salt. This efficiency is the highest reported for Au-containing composite fabrication by two-photon lithography. Transmission Electron Microscopy (TEM) analysis confirmed the presence of small metallic nanoparticles (5.4 ± 1.4 nm for long axis / 3.7 ± 0.9 nm for short axis) embedded within the polymer matrix, whilst X-ray Photoelectron Spectroscopy (XPS) confirmed that they exist in the zero valent oxidation state. UV-vis spectroscopy defined that they exhibit the property of localised surface plasmon resonance (LSPR). The capability demonstrated in this study opens up new avenues for a range of applications, including plasmonics, metamaterials, flexible electronics and biosensors.
- Published
- 2017
6. Toward Mid-Infrared, Subdiffraction, Spectral-Mapping of Human Cells and Tissue: SNIM (Scanning Near-Field Infrared Microscopy) Tip Fabrication
- Author
-
Athanasiou, Giorgos S., Ernst, Johanna, Furniss, David, Benson, Trevor M., Chauhan, Jasbinder, Middleton, John, Parmenter, Christopher D.J., Fay, Mike W., Neate, Nigel C., Shiryaev, Vladimir, Churbanov, Mikhail F., Seddon, Angela B., Parmenter, Chris, Fay, Mike, and Neate, Nigel
- Subjects
Chalcogenide Glass, Chemical Etching, Fiber Processing, Mid-Infrared, Transflection Spectra ,Physics::Accelerator Physics ,Physics::Optics ,Astrophysics::Galaxy Astrophysics - Abstract
Scanning near-field infrared microscopy (SNIM) potentially enables subdiffraction, broadband mid-infrared (MIR:3–25-μm wavelength range) spectral-mapping of human cells and tissue for real-time molecular sensing, with prospective use in disease diagnosis. SNIM requires an MIR-transmitting tip of small aperture for photon collection. Here, chalcogenide-glass optical fibers are reproducibly tapered at one end to form a MIR transmitting tip for SNIM. A wet-etching method is used to form the tip. The tapering sides of the tip are Al-coated. These Al-coated tapered-tips exhibit near-field power-confinement when acting either as the launch-end or exit-end of the MIR optical fiber. We report first time optimal cleaving of the end of the tapered tip using focused ion beam milling. A flat aperture is produced at the end of the tip, which is orthogonal to the fiber-axis and of controlled diameter. A FIB-cleaved aperture is used to collect MIR spectra of cells mounted on a transflection plate, under illumination of a synchrotron- generated wideband MIR beam.
- Published
- 2016
7. Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films
- Author
-
Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., Fisk, Ian D., and Parmenter, Christopher
- Subjects
Soy protein ,Sodium caseinate ,Probiotics ,food and beverages ,Gelatine ,Rice starch ,Corn starch - Abstract
Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91 to 1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film’s shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15-24 days for systems stored at fridge or room temperature conditions respectively.
- Published
- 2016
8. Single-molecule analysis of ferritin conformational dynamics and kinetics
- Author
-
Yousefi, Arman, Zargarbashi, Saaman, Hickman, Graham J., Assadipapari, Mahya, Zheng, Ze, Sanderson, Gabriel, Parmenter, Christopher D.J., Xu, Lei, Rahmani, Mohsen, and Ying, Cuifeng
- Published
- 2024
- Full Text
- View/download PDF
9. Making the practically impossible “Merely difficult”-Cryogenic FIB lift-out for “Damage free” soft matter imaging
- Author
-
Parmenter, Christopher D.J., primary, Fay, Michael W., additional, Hartfield, Cheryl, additional, and Eltaher, Hoda M., additional
- Published
- 2016
- Full Text
- View/download PDF
10. Binding of recombinant human coagulation factor VIII to lipid nanotubes
- Author
-
Parmenter, Christopher D.J. and Stoilova-McPhie, Svetla
- Published
- 2008
- Full Text
- View/download PDF
11. Cryo-electron microscopy of coagulation Factor VIII bound to lipid nanotubes
- Author
-
Parmenter, Christopher D.J., primary, Cane, Matthew C., additional, Zhang, Rui, additional, and Stoilova-McPhie, Svetla, additional
- Published
- 2008
- Full Text
- View/download PDF
12. Additive manufacture of complex 3D Au-containing nanocomposites by simultaneous two-photon polymerisation and photoreduction
- Author
-
Hu, Qin, Sun, Xue-Zhong, Parmenter, Christopher D.J., Fay, Michael W., Smith, Emily F., Rance, Graham A., He, Yinfeng, Zhang, Fan, Liu, Yaan, Irvine, Derek, Tuck, Christopher, Hague, Richard J.M., Wildman, Ricky D., Hu, Qin, Sun, Xue-Zhong, Parmenter, Christopher D.J., Fay, Michael W., Smith, Emily F., Rance, Graham A., He, Yinfeng, Zhang, Fan, Liu, Yaan, Irvine, Derek, Tuck, Christopher, Hague, Richard J.M., and Wildman, Ricky D.
- Abstract
The fabrication of complex three-dimensional gold-containing nanocomposite structures by simultaneous two-photon polymerisation and photoreduction is demonstrated. Increased salt delivers reduced feature sizes down to line widths as small as 78nm, a level of structural intricacy that represents a significant advance in fabrication complexity. The development of a general methodology to efficiently mix pentaerythritol triacrylate (PETA) with gold chloride hydrate (HAuCl4∙3H2O) is reported, where the gold salt concentration is adjustable on demand from zero to 20wt%. For the frst-time 7-Diethylamino-3-thenoylcoumarin (DETC) is used as the photoinitiator. Only 0.5wt% of DETC was required to promote both polymerisation and photoreduction of up to 20wt% of gold salt. This efficiency is the highest reported for Au-containing composite fabrication by two-photon lithography. Transmission Electron Microscopy (TEM) analysis confirmed the presence of small metallic nanoparticles (5.4±1.4nm for long axis / 3.7±0.9nm for short axis) embedded within the polymer matrix, whilst X-ray Photoelectron Spectroscopy (XPS) confirmed that they exist in the zero valent oxidation state. UV-vis spectroscopy defined that they exhibit the property of localised surface plasmon resonance (LSPR). The capability demonstrated in this study opens up new avenues for a range of applications, including plasmonics, metamaterials, flexible electronics and biosensors.
- Full Text
- View/download PDF
13. Optimisation of octinyl succinic anhydride starch stablised w1/o/w2 emulsions for oral destablisation of encapsulated salt and enhanced saltiness
- Author
-
Chiu, Natalie, Tarrega, Amparo, Parmenter, Christopher D.J., Hewson, Emma Louise, Wolf, Bettina, Fisk, Ian D., Chiu, Natalie, Tarrega, Amparo, Parmenter, Christopher D.J., Hewson, Emma Louise, Wolf, Bettina, and Fisk, Ian D.
- Abstract
Sodium (salt) was encapsulated within the inner water phase of w1/o/w2 food emulsions externally stabilised by starch particles with the ultimate aim of enhancing saltiness perception. The physical properties of the starch particles were modified by octenyl succinic anhydride (OSA) treatment (0 - 3 %) to vary the degree of hydrophobicity of the emulsifying starch. During oral processing native salivary amylase hydrolysed the starch and destabilised the o/w emulsion releasing the inner w/o phase and subsequently sodium into the oral cavity, resulting in a salty taste. Whilst increasing OSA treatment levels increased the stability of the emulsion, intermediate or low levels of starch modification resulted in enhanced saltiness. It is therefore proposed that 1.5% OSA modified starch is optimal for sodium delivery and 2% OSA modified starch is optimal for sodium delivery in systems that require greater process stability. It is also shown that sodium release was further enhanced by oral processing and was positively correlated with native amylase activity. The results demonstrate a promising new approach for the reduction of salt or sugar in emulsion based foods.
- Full Text
- View/download PDF
14. Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films
- Author
-
Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., Fisk, Ian D., Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., and Fisk, Ian D.
- Abstract
Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91–1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film's shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15–24 days for systems stored at fridge or room temperature conditions respectively.
- Full Text
- View/download PDF
15. Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films
- Author
-
Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., Fisk, Ian D., Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., and Fisk, Ian D.
- Abstract
Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91 to 1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film’s shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15-24 days for systems stored at fridge or room temperature conditions respectively.
- Full Text
- View/download PDF
16. Room temperature uniaxial magnetic anisotropy induced by Fe-islands in the InSe semiconductor van der Waals crystal
- Author
-
Moro, Fabrizio, Bhuiyan, Mahabub A., Kudrynskyi, Zakhar R., Puttock, Robert, Kazakova, Olga, Makarovsky, Oleg, Fay, Michael, Parmenter, Christopher D.J., Kovalyuk, Zakhar D., Fielding, Alistair John, Kern, Michal, van Slageren, Joris, Patanè, Amalia, Moro, Fabrizio, Bhuiyan, Mahabub A., Kudrynskyi, Zakhar R., Puttock, Robert, Kazakova, Olga, Makarovsky, Oleg, Fay, Michael, Parmenter, Christopher D.J., Kovalyuk, Zakhar D., Fielding, Alistair John, Kern, Michal, van Slageren, Joris, and Patanè, Amalia
- Abstract
The controlled manipulation of the spin and charge of electrons in a semiconductor has the potential to create new routes to digital electronics beyond Moore’s law, spintronics, and quantum detection and imaging for sensing applications. These technologies require a shift from traditional semiconducting and magnetic nanostructured materials. Here, a new material system is reported, which comprises the InSe semiconductor van der Waals crystal that embeds ferromagnetic Fe-islands. In contrast to many traditional semiconductors, the electronic properties of InSe are largely preserved after the incorporation of Fe. Also, this system exhibits ferromagnetic resonances and a large uniaxial magnetic anisotropy at room temperature, offering opportunities for the development of functional devices that integrate magnetic and semiconducting properties within the same material system.
- Full Text
- View/download PDF
17. Additive manufacture of complex 3D Au-containing nanocomposites by simultaneous two-photon polymerisation and photoreduction
- Author
-
Hu, Qin, Sun, Xue-Zhong, Parmenter, Christopher D.J., Fay, Michael W., Smith, Emily F., Rance, Graham A., He, Yinfeng, Zhang, Fan, Liu, Yaan, Irvine, Derek, Tuck, Christopher, Hague, Richard J.M., Wildman, Ricky D., Hu, Qin, Sun, Xue-Zhong, Parmenter, Christopher D.J., Fay, Michael W., Smith, Emily F., Rance, Graham A., He, Yinfeng, Zhang, Fan, Liu, Yaan, Irvine, Derek, Tuck, Christopher, Hague, Richard J.M., and Wildman, Ricky D.
- Abstract
The fabrication of complex three-dimensional gold-containing nanocomposite structures by simultaneous two-photon polymerisation and photoreduction is demonstrated. Increased salt delivers reduced feature sizes down to line widths as small as 78nm, a level of structural intricacy that represents a significant advance in fabrication complexity. The development of a general methodology to efficiently mix pentaerythritol triacrylate (PETA) with gold chloride hydrate (HAuCl4∙3H2O) is reported, where the gold salt concentration is adjustable on demand from zero to 20wt%. For the frst-time 7-Diethylamino-3-thenoylcoumarin (DETC) is used as the photoinitiator. Only 0.5wt% of DETC was required to promote both polymerisation and photoreduction of up to 20wt% of gold salt. This efficiency is the highest reported for Au-containing composite fabrication by two-photon lithography. Transmission Electron Microscopy (TEM) analysis confirmed the presence of small metallic nanoparticles (5.4±1.4nm for long axis / 3.7±0.9nm for short axis) embedded within the polymer matrix, whilst X-ray Photoelectron Spectroscopy (XPS) confirmed that they exist in the zero valent oxidation state. UV-vis spectroscopy defined that they exhibit the property of localised surface plasmon resonance (LSPR). The capability demonstrated in this study opens up new avenues for a range of applications, including plasmonics, metamaterials, flexible electronics and biosensors.
- Full Text
- View/download PDF
18. Biomaterial modification of urinary catheters with antimicrobials to give long-term broadspectrum antibiofilm activity
- Author
-
Fisher, Leanne E., Hook, Andrew L., Ashraf, Waheed, Yousef, Anfal, Barrett, David A., Scurr, David J., Chen, Xinyong, Smith, Emily F., Fay, Michael, Parmenter, Christopher D.J., Parkinson, Richard, Bayston, Roger, Fisher, Leanne E., Hook, Andrew L., Ashraf, Waheed, Yousef, Anfal, Barrett, David A., Scurr, David J., Chen, Xinyong, Smith, Emily F., Fay, Michael, Parmenter, Christopher D.J., Parkinson, Richard, and Bayston, Roger
- Abstract
Catheter-associated urinary tract infection (CAUTI) is the commonest hospital-acquired infection, accounting for over 100,000 hospital admissions within the USA annually. Biomaterials and processes intended to reduce the risk of bacterial colonization of the catheters for long-term users have not been successful, mainly because of the need for long duration of activity in flow conditions. Here we report the results of impregnation of urinary catheters with a combination of rifampicin, sparfloxacin and triclosan. In flow experiments, the antimicrobial catheters were able to prevent colonization by common uropathogens Proteus mirabilis, Staphylococcus aureus and Escherichia coli for 7 to 12 weeks in vitro compared with 1–3 days for other, commercially available antimicrobial catheters currently used clinically. Resistance development was minimized by careful choice of antimicrobial combinations. Drug release profiles and distribution in the polymer, and surface analysis were also carried out and the process had no deleterious effect on the mechanical performance of the catheter or its balloon. The antimicrobial catheter therefore offers for the first time a means of reducing infection and its complications in long-term urinary catheter users.
- Full Text
- View/download PDF
19. Optimisation of octinyl succinic anhydride starch stablised w1/o/w2 emulsions for oral destablisation of encapsulated salt and enhanced saltiness
- Author
-
Chiu, Natalie, Tarrega, Amparo, Parmenter, Christopher D.J., Hewson, Emma Louise, Wolf, Bettina, Fisk, Ian D., Chiu, Natalie, Tarrega, Amparo, Parmenter, Christopher D.J., Hewson, Emma Louise, Wolf, Bettina, and Fisk, Ian D.
- Abstract
Sodium (salt) was encapsulated within the inner water phase of w1/o/w2 food emulsions externally stabilised by starch particles with the ultimate aim of enhancing saltiness perception. The physical properties of the starch particles were modified by octenyl succinic anhydride (OSA) treatment (0 - 3 %) to vary the degree of hydrophobicity of the emulsifying starch. During oral processing native salivary amylase hydrolysed the starch and destabilised the o/w emulsion releasing the inner w/o phase and subsequently sodium into the oral cavity, resulting in a salty taste. Whilst increasing OSA treatment levels increased the stability of the emulsion, intermediate or low levels of starch modification resulted in enhanced saltiness. It is therefore proposed that 1.5% OSA modified starch is optimal for sodium delivery and 2% OSA modified starch is optimal for sodium delivery in systems that require greater process stability. It is also shown that sodium release was further enhanced by oral processing and was positively correlated with native amylase activity. The results demonstrate a promising new approach for the reduction of salt or sugar in emulsion based foods.
- Full Text
- View/download PDF
20. Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films
- Author
-
Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., Fisk, Ian D., Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., and Fisk, Ian D.
- Abstract
Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91–1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film's shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15–24 days for systems stored at fridge or room temperature conditions respectively.
- Full Text
- View/download PDF
21. Multivariate analysis of 3D ToF-SIMS images: method validation and application to cultured neuronal networks
- Author
-
Van Nuffel, Sebastiaan, Parmenter, Christopher D.J., Scurr, David J., Russell, Noah A., Zelzer, Mischa, Van Nuffel, Sebastiaan, Parmenter, Christopher D.J., Scurr, David J., Russell, Noah A., and Zelzer, Mischa
- Abstract
Advanced data analysis tools are crucial for the application of ToF-SIMS analysis to biological samples. Here, we demonstrate that by using a training set approach principal components analysis (PCA) can be performed on large 3D ToF-SIMS images of neuronal cell cultures. The method readily provides access to sample component information and significantly improves the images’ signal-to-noise ratio (SNR).
- Full Text
- View/download PDF
22. Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films
- Author
-
Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., Fisk, Ian D., Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., and Fisk, Ian D.
- Abstract
Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91 to 1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film’s shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15-24 days for systems stored at fridge or room temperature conditions respectively.
- Full Text
- View/download PDF
23. Room temperature uniaxial magnetic anisotropy induced by Fe-islands in the InSe semiconductor van der Waals crystal
- Author
-
Moro, Fabrizio, Bhuiyan, Mahabub A., Kudrynskyi, Zakhar R., Puttock, Robert, Kazakova, Olga, Makarovsky, Oleg, Fay, Michael, Parmenter, Christopher D.J., Kovalyuk, Zakhar D., Fielding, Alistair John, Kern, Michal, van Slageren, Joris, Patanè, Amalia, Moro, Fabrizio, Bhuiyan, Mahabub A., Kudrynskyi, Zakhar R., Puttock, Robert, Kazakova, Olga, Makarovsky, Oleg, Fay, Michael, Parmenter, Christopher D.J., Kovalyuk, Zakhar D., Fielding, Alistair John, Kern, Michal, van Slageren, Joris, and Patanè, Amalia
- Abstract
The controlled manipulation of the spin and charge of electrons in a semiconductor has the potential to create new routes to digital electronics beyond Moore’s law, spintronics, and quantum detection and imaging for sensing applications. These technologies require a shift from traditional semiconducting and magnetic nanostructured materials. Here, a new material system is reported, which comprises the InSe semiconductor van der Waals crystal that embeds ferromagnetic Fe-islands. In contrast to many traditional semiconductors, the electronic properties of InSe are largely preserved after the incorporation of Fe. Also, this system exhibits ferromagnetic resonances and a large uniaxial magnetic anisotropy at room temperature, offering opportunities for the development of functional devices that integrate magnetic and semiconducting properties within the same material system.
- Full Text
- View/download PDF
24. Additive manufacture of complex 3D Au-containing nanocomposites by simultaneous two-photon polymerisation and photoreduction
- Author
-
Hu, Qin, Sun, Xue-Zhong, Parmenter, Christopher D.J., Fay, Michael W., Smith, Emily F., Rance, Graham A., He, Yinfeng, Zhang, Fan, Liu, Yaan, Irvine, Derek, Tuck, Christopher, Hague, Richard J.M., Wildman, Ricky D., Hu, Qin, Sun, Xue-Zhong, Parmenter, Christopher D.J., Fay, Michael W., Smith, Emily F., Rance, Graham A., He, Yinfeng, Zhang, Fan, Liu, Yaan, Irvine, Derek, Tuck, Christopher, Hague, Richard J.M., and Wildman, Ricky D.
- Abstract
The fabrication of complex three-dimensional gold-containing nanocomposite structures by simultaneous two-photon polymerisation and photoreduction is demonstrated. Increased salt delivers reduced feature sizes down to line widths as small as 78nm, a level of structural intricacy that represents a significant advance in fabrication complexity. The development of a general methodology to efficiently mix pentaerythritol triacrylate (PETA) with gold chloride hydrate (HAuCl4∙3H2O) is reported, where the gold salt concentration is adjustable on demand from zero to 20wt%. For the frst-time 7-Diethylamino-3-thenoylcoumarin (DETC) is used as the photoinitiator. Only 0.5wt% of DETC was required to promote both polymerisation and photoreduction of up to 20wt% of gold salt. This efficiency is the highest reported for Au-containing composite fabrication by two-photon lithography. Transmission Electron Microscopy (TEM) analysis confirmed the presence of small metallic nanoparticles (5.4±1.4nm for long axis / 3.7±0.9nm for short axis) embedded within the polymer matrix, whilst X-ray Photoelectron Spectroscopy (XPS) confirmed that they exist in the zero valent oxidation state. UV-vis spectroscopy defined that they exhibit the property of localised surface plasmon resonance (LSPR). The capability demonstrated in this study opens up new avenues for a range of applications, including plasmonics, metamaterials, flexible electronics and biosensors.
- Full Text
- View/download PDF
25. Biomaterial modification of urinary catheters with antimicrobials to give long-term broadspectrum antibiofilm activity
- Author
-
Fisher, Leanne E., Hook, Andrew L., Ashraf, Waheed, Yousef, Anfal, Barrett, David A., Scurr, David J., Chen, Xinyong, Smith, Emily F., Fay, Michael, Parmenter, Christopher D.J., Parkinson, Richard, Bayston, Roger, Fisher, Leanne E., Hook, Andrew L., Ashraf, Waheed, Yousef, Anfal, Barrett, David A., Scurr, David J., Chen, Xinyong, Smith, Emily F., Fay, Michael, Parmenter, Christopher D.J., Parkinson, Richard, and Bayston, Roger
- Abstract
Catheter-associated urinary tract infection (CAUTI) is the commonest hospital-acquired infection, accounting for over 100,000 hospital admissions within the USA annually. Biomaterials and processes intended to reduce the risk of bacterial colonization of the catheters for long-term users have not been successful, mainly because of the need for long duration of activity in flow conditions. Here we report the results of impregnation of urinary catheters with a combination of rifampicin, sparfloxacin and triclosan. In flow experiments, the antimicrobial catheters were able to prevent colonization by common uropathogens Proteus mirabilis, Staphylococcus aureus and Escherichia coli for 7 to 12 weeks in vitro compared with 1–3 days for other, commercially available antimicrobial catheters currently used clinically. Resistance development was minimized by careful choice of antimicrobial combinations. Drug release profiles and distribution in the polymer, and surface analysis were also carried out and the process had no deleterious effect on the mechanical performance of the catheter or its balloon. The antimicrobial catheter therefore offers for the first time a means of reducing infection and its complications in long-term urinary catheter users.
- Full Text
- View/download PDF
26. Optimisation of octinyl succinic anhydride starch stablised w1/o/w2 emulsions for oral destablisation of encapsulated salt and enhanced saltiness
- Author
-
Chiu, Natalie, Tarrega, Amparo, Parmenter, Christopher D.J., Hewson, Emma Louise, Wolf, Bettina, Fisk, Ian D., Chiu, Natalie, Tarrega, Amparo, Parmenter, Christopher D.J., Hewson, Emma Louise, Wolf, Bettina, and Fisk, Ian D.
- Abstract
Sodium (salt) was encapsulated within the inner water phase of w1/o/w2 food emulsions externally stabilised by starch particles with the ultimate aim of enhancing saltiness perception. The physical properties of the starch particles were modified by octenyl succinic anhydride (OSA) treatment (0 - 3 %) to vary the degree of hydrophobicity of the emulsifying starch. During oral processing native salivary amylase hydrolysed the starch and destabilised the o/w emulsion releasing the inner w/o phase and subsequently sodium into the oral cavity, resulting in a salty taste. Whilst increasing OSA treatment levels increased the stability of the emulsion, intermediate or low levels of starch modification resulted in enhanced saltiness. It is therefore proposed that 1.5% OSA modified starch is optimal for sodium delivery and 2% OSA modified starch is optimal for sodium delivery in systems that require greater process stability. It is also shown that sodium release was further enhanced by oral processing and was positively correlated with native amylase activity. The results demonstrate a promising new approach for the reduction of salt or sugar in emulsion based foods.
- Full Text
- View/download PDF
27. Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films
- Author
-
Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., Fisk, Ian D., Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., and Fisk, Ian D.
- Abstract
Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91 to 1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film’s shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15-24 days for systems stored at fridge or room temperature conditions respectively.
- Full Text
- View/download PDF
28. Multivariate analysis of 3D ToF-SIMS images: method validation and application to cultured neuronal networks
- Author
-
Van Nuffel, Sebastiaan, Parmenter, Christopher D.J., Scurr, David J., Russell, Noah A., Zelzer, Mischa, Van Nuffel, Sebastiaan, Parmenter, Christopher D.J., Scurr, David J., Russell, Noah A., and Zelzer, Mischa
- Abstract
Advanced data analysis tools are crucial for the application of ToF-SIMS analysis to biological samples. Here, we demonstrate that by using a training set approach principal components analysis (PCA) can be performed on large 3D ToF-SIMS images of neuronal cell cultures. The method readily provides access to sample component information and significantly improves the images’ signal-to-noise ratio (SNR).
- Full Text
- View/download PDF
29. Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films
- Author
-
Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., Fisk, Ian D., Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., and Fisk, Ian D.
- Abstract
Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91–1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film's shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15–24 days for systems stored at fridge or room temperature conditions respectively.
- Full Text
- View/download PDF
30. Room temperature uniaxial magnetic anisotropy induced by Fe-islands in the InSe semiconductor van der Waals crystal
- Author
-
Moro, Fabrizio, Bhuiyan, Mahabub A., Kudrynskyi, Zakhar R., Puttock, Robert, Kazakova, Olga, Makarovsky, Oleg, Fay, Michael, Parmenter, Christopher D.J., Kovalyuk, Zakhar D., Fielding, Alistair John, Kern, Michal, van Slageren, Joris, Patanè, Amalia, Moro, Fabrizio, Bhuiyan, Mahabub A., Kudrynskyi, Zakhar R., Puttock, Robert, Kazakova, Olga, Makarovsky, Oleg, Fay, Michael, Parmenter, Christopher D.J., Kovalyuk, Zakhar D., Fielding, Alistair John, Kern, Michal, van Slageren, Joris, and Patanè, Amalia
- Abstract
The controlled manipulation of the spin and charge of electrons in a semiconductor has the potential to create new routes to digital electronics beyond Moore’s law, spintronics, and quantum detection and imaging for sensing applications. These technologies require a shift from traditional semiconducting and magnetic nanostructured materials. Here, a new material system is reported, which comprises the InSe semiconductor van der Waals crystal that embeds ferromagnetic Fe-islands. In contrast to many traditional semiconductors, the electronic properties of InSe are largely preserved after the incorporation of Fe. Also, this system exhibits ferromagnetic resonances and a large uniaxial magnetic anisotropy at room temperature, offering opportunities for the development of functional devices that integrate magnetic and semiconducting properties within the same material system.
- Full Text
- View/download PDF
31. Additive manufacture of complex 3D Au-containing nanocomposites by simultaneous two-photon polymerisation and photoreduction
- Author
-
Hu, Qin, Sun, Xue-Zhong, Parmenter, Christopher D.J., Fay, Michael W., Smith, Emily F., Rance, Graham A., He, Yinfeng, Zhang, Fan, Liu, Yaan, Irvine, Derek, Tuck, Christopher, Hague, Richard J.M., Wildman, Ricky D., Hu, Qin, Sun, Xue-Zhong, Parmenter, Christopher D.J., Fay, Michael W., Smith, Emily F., Rance, Graham A., He, Yinfeng, Zhang, Fan, Liu, Yaan, Irvine, Derek, Tuck, Christopher, Hague, Richard J.M., and Wildman, Ricky D.
- Abstract
The fabrication of complex three-dimensional gold-containing nanocomposite structures by simultaneous two-photon polymerisation and photoreduction is demonstrated. Increased salt delivers reduced feature sizes down to line widths as small as 78nm, a level of structural intricacy that represents a significant advance in fabrication complexity. The development of a general methodology to efficiently mix pentaerythritol triacrylate (PETA) with gold chloride hydrate (HAuCl4∙3H2O) is reported, where the gold salt concentration is adjustable on demand from zero to 20wt%. For the frst-time 7-Diethylamino-3-thenoylcoumarin (DETC) is used as the photoinitiator. Only 0.5wt% of DETC was required to promote both polymerisation and photoreduction of up to 20wt% of gold salt. This efficiency is the highest reported for Au-containing composite fabrication by two-photon lithography. Transmission Electron Microscopy (TEM) analysis confirmed the presence of small metallic nanoparticles (5.4±1.4nm for long axis / 3.7±0.9nm for short axis) embedded within the polymer matrix, whilst X-ray Photoelectron Spectroscopy (XPS) confirmed that they exist in the zero valent oxidation state. UV-vis spectroscopy defined that they exhibit the property of localised surface plasmon resonance (LSPR). The capability demonstrated in this study opens up new avenues for a range of applications, including plasmonics, metamaterials, flexible electronics and biosensors.
- Full Text
- View/download PDF
32. Biomaterial modification of urinary catheters with antimicrobials to give long-term broadspectrum antibiofilm activity
- Author
-
Fisher, Leanne E., Hook, Andrew L., Ashraf, Waheed, Yousef, Anfal, Barrett, David A., Scurr, David J., Chen, Xinyong, Smith, Emily F., Fay, Michael, Parmenter, Christopher D.J., Parkinson, Richard, Bayston, Roger, Fisher, Leanne E., Hook, Andrew L., Ashraf, Waheed, Yousef, Anfal, Barrett, David A., Scurr, David J., Chen, Xinyong, Smith, Emily F., Fay, Michael, Parmenter, Christopher D.J., Parkinson, Richard, and Bayston, Roger
- Abstract
Catheter-associated urinary tract infection (CAUTI) is the commonest hospital-acquired infection, accounting for over 100,000 hospital admissions within the USA annually. Biomaterials and processes intended to reduce the risk of bacterial colonization of the catheters for long-term users have not been successful, mainly because of the need for long duration of activity in flow conditions. Here we report the results of impregnation of urinary catheters with a combination of rifampicin, sparfloxacin and triclosan. In flow experiments, the antimicrobial catheters were able to prevent colonization by common uropathogens Proteus mirabilis, Staphylococcus aureus and Escherichia coli for 7 to 12 weeks in vitro compared with 1–3 days for other, commercially available antimicrobial catheters currently used clinically. Resistance development was minimized by careful choice of antimicrobial combinations. Drug release profiles and distribution in the polymer, and surface analysis were also carried out and the process had no deleterious effect on the mechanical performance of the catheter or its balloon. The antimicrobial catheter therefore offers for the first time a means of reducing infection and its complications in long-term urinary catheter users.
- Full Text
- View/download PDF
33. Optimisation of octinyl succinic anhydride starch stablised w1/o/w2 emulsions for oral destablisation of encapsulated salt and enhanced saltiness
- Author
-
Chiu, Natalie, Tarrega, Amparo, Parmenter, Christopher D.J., Hewson, Emma Louise, Wolf, Bettina, Fisk, Ian D., Chiu, Natalie, Tarrega, Amparo, Parmenter, Christopher D.J., Hewson, Emma Louise, Wolf, Bettina, and Fisk, Ian D.
- Abstract
Sodium (salt) was encapsulated within the inner water phase of w1/o/w2 food emulsions externally stabilised by starch particles with the ultimate aim of enhancing saltiness perception. The physical properties of the starch particles were modified by octenyl succinic anhydride (OSA) treatment (0 - 3 %) to vary the degree of hydrophobicity of the emulsifying starch. During oral processing native salivary amylase hydrolysed the starch and destabilised the o/w emulsion releasing the inner w/o phase and subsequently sodium into the oral cavity, resulting in a salty taste. Whilst increasing OSA treatment levels increased the stability of the emulsion, intermediate or low levels of starch modification resulted in enhanced saltiness. It is therefore proposed that 1.5% OSA modified starch is optimal for sodium delivery and 2% OSA modified starch is optimal for sodium delivery in systems that require greater process stability. It is also shown that sodium release was further enhanced by oral processing and was positively correlated with native amylase activity. The results demonstrate a promising new approach for the reduction of salt or sugar in emulsion based foods.
- Full Text
- View/download PDF
34. Room temperature uniaxial magnetic anisotropy induced by Fe-islands in the InSe semiconductor van der Waals crystal
- Author
-
Moro, Fabrizio, Bhuiyan, Mahabub A., Kudrynskyi, Zakhar R., Puttock, Robert, Kazakova, Olga, Makarovsky, Oleg, Fay, Michael, Parmenter, Christopher D.J., Kovalyuk, Zakhar D., Fielding, Alistair John, Kern, Michal, van Slageren, Joris, Patanè, Amalia, Moro, Fabrizio, Bhuiyan, Mahabub A., Kudrynskyi, Zakhar R., Puttock, Robert, Kazakova, Olga, Makarovsky, Oleg, Fay, Michael, Parmenter, Christopher D.J., Kovalyuk, Zakhar D., Fielding, Alistair John, Kern, Michal, van Slageren, Joris, and Patanè, Amalia
- Abstract
The controlled manipulation of the spin and charge of electrons in a semiconductor has the potential to create new routes to digital electronics beyond Moore’s law, spintronics, and quantum detection and imaging for sensing applications. These technologies require a shift from traditional semiconducting and magnetic nanostructured materials. Here, a new material system is reported, which comprises the InSe semiconductor van der Waals crystal that embeds ferromagnetic Fe-islands. In contrast to many traditional semiconductors, the electronic properties of InSe are largely preserved after the incorporation of Fe. Also, this system exhibits ferromagnetic resonances and a large uniaxial magnetic anisotropy at room temperature, offering opportunities for the development of functional devices that integrate magnetic and semiconducting properties within the same material system.
- Full Text
- View/download PDF
35. Additive manufacture of complex 3D Au-containing nanocomposites by simultaneous two-photon polymerisation and photoreduction
- Author
-
Hu, Qin, Sun, Xue-Zhong, Parmenter, Christopher D.J., Fay, Michael W., Smith, Emily F., Rance, Graham A., He, Yinfeng, Zhang, Fan, Liu, Yaan, Irvine, Derek, Tuck, Christopher, Hague, Richard J.M., Wildman, Ricky D., Hu, Qin, Sun, Xue-Zhong, Parmenter, Christopher D.J., Fay, Michael W., Smith, Emily F., Rance, Graham A., He, Yinfeng, Zhang, Fan, Liu, Yaan, Irvine, Derek, Tuck, Christopher, Hague, Richard J.M., and Wildman, Ricky D.
- Abstract
The fabrication of complex three-dimensional gold-containing nanocomposite structures by simultaneous two-photon polymerisation and photoreduction is demonstrated. Increased salt delivers reduced feature sizes down to line widths as small as 78nm, a level of structural intricacy that represents a significant advance in fabrication complexity. The development of a general methodology to efficiently mix pentaerythritol triacrylate (PETA) with gold chloride hydrate (HAuCl4∙3H2O) is reported, where the gold salt concentration is adjustable on demand from zero to 20wt%. For the frst-time 7-Diethylamino-3-thenoylcoumarin (DETC) is used as the photoinitiator. Only 0.5wt% of DETC was required to promote both polymerisation and photoreduction of up to 20wt% of gold salt. This efficiency is the highest reported for Au-containing composite fabrication by two-photon lithography. Transmission Electron Microscopy (TEM) analysis confirmed the presence of small metallic nanoparticles (5.4±1.4nm for long axis / 3.7±0.9nm for short axis) embedded within the polymer matrix, whilst X-ray Photoelectron Spectroscopy (XPS) confirmed that they exist in the zero valent oxidation state. UV-vis spectroscopy defined that they exhibit the property of localised surface plasmon resonance (LSPR). The capability demonstrated in this study opens up new avenues for a range of applications, including plasmonics, metamaterials, flexible electronics and biosensors.
- Full Text
- View/download PDF
36. Biomaterial modification of urinary catheters with antimicrobials to give long-term broadspectrum antibiofilm activity
- Author
-
Fisher, Leanne E., Hook, Andrew L., Ashraf, Waheed, Yousef, Anfal, Barrett, David A., Scurr, David J., Chen, Xinyong, Smith, Emily F., Fay, Michael, Parmenter, Christopher D.J., Parkinson, Richard, Bayston, Roger, Fisher, Leanne E., Hook, Andrew L., Ashraf, Waheed, Yousef, Anfal, Barrett, David A., Scurr, David J., Chen, Xinyong, Smith, Emily F., Fay, Michael, Parmenter, Christopher D.J., Parkinson, Richard, and Bayston, Roger
- Abstract
Catheter-associated urinary tract infection (CAUTI) is the commonest hospital-acquired infection, accounting for over 100,000 hospital admissions within the USA annually. Biomaterials and processes intended to reduce the risk of bacterial colonization of the catheters for long-term users have not been successful, mainly because of the need for long duration of activity in flow conditions. Here we report the results of impregnation of urinary catheters with a combination of rifampicin, sparfloxacin and triclosan. In flow experiments, the antimicrobial catheters were able to prevent colonization by common uropathogens Proteus mirabilis, Staphylococcus aureus and Escherichia coli for 7 to 12 weeks in vitro compared with 1–3 days for other, commercially available antimicrobial catheters currently used clinically. Resistance development was minimized by careful choice of antimicrobial combinations. Drug release profiles and distribution in the polymer, and surface analysis were also carried out and the process had no deleterious effect on the mechanical performance of the catheter or its balloon. The antimicrobial catheter therefore offers for the first time a means of reducing infection and its complications in long-term urinary catheter users.
- Full Text
- View/download PDF
37. Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films
- Author
-
Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., Fisk, Ian D., Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., and Fisk, Ian D.
- Abstract
Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91–1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film's shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15–24 days for systems stored at fridge or room temperature conditions respectively.
- Full Text
- View/download PDF
38. Multivariate analysis of 3D ToF-SIMS images: method validation and application to cultured neuronal networks
- Author
-
Van Nuffel, Sebastiaan, Parmenter, Christopher D.J., Scurr, David J., Russell, Noah A., Zelzer, Mischa, Van Nuffel, Sebastiaan, Parmenter, Christopher D.J., Scurr, David J., Russell, Noah A., and Zelzer, Mischa
- Abstract
Advanced data analysis tools are crucial for the application of ToF-SIMS analysis to biological samples. Here, we demonstrate that by using a training set approach principal components analysis (PCA) can be performed on large 3D ToF-SIMS images of neuronal cell cultures. The method readily provides access to sample component information and significantly improves the images’ signal-to-noise ratio (SNR).
- Full Text
- View/download PDF
39. Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films
- Author
-
Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., Fisk, Ian D., Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., and Fisk, Ian D.
- Abstract
Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91 to 1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film’s shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15-24 days for systems stored at fridge or room temperature conditions respectively.
- Full Text
- View/download PDF
40. Optimisation of octinyl succinic anhydride starch stablised w1/o/w2 emulsions for oral destablisation of encapsulated salt and enhanced saltiness
- Author
-
Chiu, Natalie, Tarrega, Amparo, Parmenter, Christopher D.J., Hewson, Emma Louise, Wolf, Bettina, Fisk, Ian D., Chiu, Natalie, Tarrega, Amparo, Parmenter, Christopher D.J., Hewson, Emma Louise, Wolf, Bettina, and Fisk, Ian D.
- Abstract
Sodium (salt) was encapsulated within the inner water phase of w1/o/w2 food emulsions externally stabilised by starch particles with the ultimate aim of enhancing saltiness perception. The physical properties of the starch particles were modified by octenyl succinic anhydride (OSA) treatment (0 - 3 %) to vary the degree of hydrophobicity of the emulsifying starch. During oral processing native salivary amylase hydrolysed the starch and destabilised the o/w emulsion releasing the inner w/o phase and subsequently sodium into the oral cavity, resulting in a salty taste. Whilst increasing OSA treatment levels increased the stability of the emulsion, intermediate or low levels of starch modification resulted in enhanced saltiness. It is therefore proposed that 1.5% OSA modified starch is optimal for sodium delivery and 2% OSA modified starch is optimal for sodium delivery in systems that require greater process stability. It is also shown that sodium release was further enhanced by oral processing and was positively correlated with native amylase activity. The results demonstrate a promising new approach for the reduction of salt or sugar in emulsion based foods.
- Full Text
- View/download PDF
41. Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films
- Author
-
Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., Fisk, Ian D., Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., and Fisk, Ian D.
- Abstract
Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91–1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film's shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15–24 days for systems stored at fridge or room temperature conditions respectively.
- Full Text
- View/download PDF
42. Multivariate analysis of 3D ToF-SIMS images: method validation and application to cultured neuronal networks
- Author
-
Van Nuffel, Sebastiaan, Parmenter, Christopher D.J., Scurr, David J., Russell, Noah A., Zelzer, Mischa, Van Nuffel, Sebastiaan, Parmenter, Christopher D.J., Scurr, David J., Russell, Noah A., and Zelzer, Mischa
- Abstract
Advanced data analysis tools are crucial for the application of ToF-SIMS analysis to biological samples. Here, we demonstrate that by using a training set approach principal components analysis (PCA) can be performed on large 3D ToF-SIMS images of neuronal cell cultures. The method readily provides access to sample component information and significantly improves the images’ signal-to-noise ratio (SNR).
- Full Text
- View/download PDF
43. Compositional and physicochemical factors governing the viability of Lactobacillus rhamnosus GG embedded in starch-protein based edible films
- Author
-
Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., Fisk, Ian D., Soukoulis, Christos, Singh, Poonam, Macnaughtan, William, Parmenter, Christopher D.J., and Fisk, Ian D.
- Abstract
Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91 to 1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate – rice starch based films offering the most enhanced stability. The film’s shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15-24 days for systems stored at fridge or room temperature conditions respectively.
- Full Text
- View/download PDF
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