197,079 research outputs found
From food waste to high value transformative healthcare solutions
No full textChitosan, a linear, cationic copolymer, produced from the deacetylation of chitin found in fungal cell walls and crustaceans, with the latter being a major waste product of the fishing industry, is gaining momentum in efforts towards sustainable healthcare. Chitosan has been designated ‘Generally Recognized As Safe (GRAS)’ by the FDA and is approved for use in dietary supplements as well as applications in wound dressings and gels, but ambition goes well beyond this and includes formulations of intelligent stimuli responsive scaffolds for tissue engineering and advanced drug delivery systems. In this talk, we will present key findings from our studies ranging from chitosan purification and endotoxin removal [1], biodegradation and biocompatibility [1-3], to novel injectable, implantable [4] and recently developed transdermal formulations for drug delivery of both small drug molecules and biologics. 1. Effective Endotoxin Removal from Chitosan That Preserves Chemical Structure and Improves Compatibility with Immune Cells, Sophie L Reay, Emma L Jackson, Daniel Salthouse, Ana Marina Ferreira, Catharien MU Hilkens, Katarina Novakovic, Polymers, 2023. 2. In vitro evaluation of the biodegradability of chitosan–genipin hydrogels, Sophie L Reay, Emma L Jackson, Ana M Ferreira, Catharien MU Hilkens, Katarina Novakovic, Materials Advances, 2022. 3. Genipin‐crosslinked chitosan hydrogels: Preliminary evaluation of the in vitro biocompatibility and biodegradation, Nga TN Vo, Lei Huang, Henrique Lemos, Andrew L Mellor, Katarina Novakovic, Journal of Applied Polymer Science, 2021. 4. Poly (ethylene glycol)‐interpenetrated genipin‐crosslinked chitosan hydrogels: Structure, pH responsiveness, gelation kinetics, and rheology, Nga TN Vo, Lei Huang, Henrique Lemos, Andrew Mellor, Katarina Novakovic, Journal of Applied Polymer Science, 2020
Oscillations in the concentration of phenylacetylene and its carbonylation products
No full textThe oscillatory nature of the palladium catalysed phenylacetylene oxidative carbonylation (PCPOC) reaction was first reported by Temkin and colleagues1-4. It was demonstrated that the PCPOC reaction in a catalytic system (PdI2, KI, O2, NaOAc in methanol) exhibits oscillations in redox potential, pH and the rate of CO/O2 gas mixture consumption. Later on, Novakovic and colleagues5-8 investigated the characteristics of the PCPOC reaction and carried out this reaction in a calorimeter for the first time. They reported simultaneous oscillations in pH and rate of heat evolution (Qr)5, the influence of oscillations on product selectivity as well as the dynamics of product formation6 and the influence of the reaction temperature on the period and amplitude of oscillations7. In addition, the products resulting from this reaction have been reported.8 To make use of all observations the reaction mechanism responsible for the oscillations needs to be understood. In this quest, the reaction network responsible for the initial reactions of PdI2 in this system were studied.9 Subsequently, the role of water in this oscillatory system, as well as the importance of the order of reactant addition and its effect on product formation have been reported.10 This recent study enabled the proposal of a prospective theory to describe the oscillatory behaviour. In this work the existence of oscillatory behaviour in the concentration of phenylacetylene and carbonylation products (E-3-phenylacrylic acid methyl ester, Z-2-phenylbut-2-enedioic acid dimethyl ester, E-2-phenylbut-2-enedioic acid dimethyl ester, 5,5-dimethoxy-3-phenylfuran-2(5H)-one and 3-phenylfuran-2,5-dione) is uncovered. The amplitude of the oscillations in phenylacetylene was as high as 34% relative to the initial amount of phenylacetylene added to the system. 1. A.V. Malashkevich, L.G. Bruk and O.N. Temkin, J. Phys. Chem. A, 1997, 101 (51), 9825-9827; 2. S.N. Gorodskii, A.N. Zakharov, A.V. Kulik, L.G. Bruk and O.N. Temkin, Kinet. Cat., 2001, 42 (2), 251-263; 3. S.N. Gorodskii, E.S. Kalenova, L.G. Bruk and O.N. Temkin, Russ. Chem. Bull., 2003, 52 (7), 1524-1543; 4. O.N. Temkin and L.G. Bruk, Kinet. Cat., 2003, 44 (5), 601-617; 5. K. Novakovic, C. Grosjean, S.K. Scott, A. Whiting, M.J. Willis and A.R. Wright, Chem. Phys. Lett., 2007, 435, 142–147; 6. K. Novakovic, C. Grosjean, S.K. Scott, A. Whiting, M.J. Willis and A.R. Wright, Phys. Chem. Chem. Phys., 2008, 10, 749-753; 7. K. Novakovic, A. Mukherjee, M. Willis, A. Wright and S. Scott, Phys. Chem. Chem. Phys., 2009, 11, 9044-9049; 8. C. Grosjean, K. Novakovic, S.K. Scott, A. Whiting, M.J. Willis and A.R. Wright, J. Mol. Cat. A, 2008, 284, 33-39; 9. K. Novakovic, J. Parker, Int. J. Chem. Eng, 2011; 10. K. Novakovic, J. Parker, Submitted
Meet Met Net - Awareness and design in hyper-technology era
No full textThe complex relationship between man and technology is the starting point of an interesting design process aiming to highlight the lack of awareness in most of the behavioral choices of man. The man is distinguished by its nature of finding short-term solutions, with the almost complete inability of prefiguring repercussions resulting from his unconscious decisions. The technology, on the other hand is growing and developing fast, becoming day by day more autonomous and uncontrollable.
Specific attention is deserved by those technological innovations that can cause unpredicted impacts on human, his principles, values and behaviors: knowing history by its sociological and behavioral implications allows us to recognize some recursive patterns that can then be transformed into opportunities.
The goal is not an attempt to predict future trends in technological innovation but to find the right formula in order to raise the level of responsibility in individuals' behavior. Not by imposing rules but giving people the right awareness in order to make conscious choices and to guarantee a responsible behavior.
The role of the designer and the fields where he can intervene are identified and an area of interest is delimited specifically to the ambit of the 3D printing, enhancing its potential property of changing both technological and human systems. A first answer to the problems triggered by 3D printing can be found, indeed, in the positive phenomena that are activated within collaborating groups by sharing space and knowledge in communities with a bottom-up approach. The designer is actively involved within the entire system, directing behaviors toward the correct ethical and moral responsibility. Therefore, 3D printing does not turn into another behavioral, social, economic and environmental failure
Satureja montana essential oil and Cotinus coggygria extract to improve microbial quality and the shelf-life of carrot-orange juice.
No full textNatural antimicrobial agentsderived from herbs and plants have been used for
millenia in medicine and food preservation. Indeed, essential oils (EO) and plants extracts
(PE), in addition to contributing to flavour and taste, can act against food microbiota thus
enhancing its stability. Moreover, recently, the consumers’ demand for naturalproducts – free
of chemical preservatives - has been strongly increased.
Fruit-based juices are susceptible to spoilage microorganisms,mainly yeasts and lactic acid
bacteria, which negatively affect their organoleptic and nutritional properties making the
product unacceptable to consumers.
The aim of this study was to evaluate the effects ofnatural compounds, i.e. EO of Satureja
montana and PE of Cotinus coggygria, in combination with mild thermal treatments on shelflife of carrot-orange juice and its microbial stability. In particular, viability of two spoilage
microrganims Saccharomyces cerevisiae and Lactobacillus plantarumwas addressed.
The EO and PE were preliminarly characterized by gascromatographic analises
whichshowedthat S. montana was composed mainly by carvacrol and o-cimene, while the
main components of C. coggygria were sulfuretin and fustin.
Both S. montana EO and C. coggygriaPE displayed a good antimicrobial activity against S.
cerevisiae, with minimum inhibitory concentration (MIC) values of 0.351 mg/ml and
0.094mg/ml, respectively. On the other hand, Lactobacillus plantarum was more resistant
thanS. cerevisiae(MIC >0.5 mg/ml).
The freshcarrot-orange juice was added with the S. montanaEO or C. coggygriaPE at MIC/4
concentrations for S. cerevisiae. Following its deliberatecontamination with the spoilage
microrganisms (4 LogCFU/ml), samples were heat treated (60 °C for 2 or 5 min) and stored at room temperature for 9 days or 4°C for 50 days. Changes insurviving spoilage microbiota, pH,
colour and antioxidant activity were monitored over storage.
Overall, the results highlighted the possibility of stabilizing a juice with a high pH (5.4)by
applying the "Hurdle Technology". The natural compounds enhanced the efficacy of heat
treatments in inactivating/damaging the spoilage biota and delaying its recovery over storage.
Moreover, no significant changes in the pH and color of the juices were found during storage,
while limited variations in the antioxidant activity were detecte
Transport of oxygen at the surface of liquid metals: models and experiments in Advances in Science and Tecnology
No full textEffects of 200 keV Ar-ions irradiation on the structural and optical properties of reactively sputtered CrN films
No full textModification in structural and optical properties of chromium-nitride (CrN) films induced by argon ion irradiation and thermal annealings were investigated using various experimental techniques. CrN films deposited by d.c. reactive sputtering on Si substrate were implanted with 200 keV argon ions, at fluences of 5-20 x 10(15) ions/cm(2). As-implanted samples were then annealed in vacuum, for 2 h at 700 degrees C. Rutherford backscattering spectrometry, X-ray diffraction, cross-sectional (high-resolution) transmission electron microscopy and spectroscopic ellipsometry (SE) measurements were carried out in order to study structural and optical properties of the layers. After irradiation with 200 keV Ar ions a damaged surface layer of nanocrystalline structure was generated, which extended beyond the implantation profile, but left an undamaged bottom zone. Partial loss of columnar structure observed in implanted samples was recovered after annealing at 700 degrees C and CrN started to decompose to Cr2N. This layer geometry determined from transmission electron microscopy was inferred in the analysis of SE data using the combined Drude and Tauc-Lorentz model, and the variation of the optical bandgap was deduced. The results are discussed on the basis of the changes induced in the microstructure. It was found that the optical properties of the layers are strongly dependent on the defects' concentration of CrN. (C) 2016 Elsevier B.V. All rights reserved
Study of dynamic surface tension of molten silicon: development of experiments and models
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Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
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