ORCID Profile
0000-0002-9940-2194
Current Organisations
Monash University
,
Deakin University
,
Swinburne University of Technology
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8RP90012D
Abstract: Correction for ‘Investigating student and staff perceptions of students' experiences in teaching laboratories through the lens of meaningful learning’ by Stephen R. George-Williams et al. , Chem. Educ. Res. Pract. , 2019, DOI: 10.1039/c8rp00188j.
Publisher: Springer Science and Business Media LLC
Date: 07-05-2013
Abstract: Lignocellulosic biomass is one of the most promising renewable and clean energy resources to reduce greenhouse gas emissions and dependence on fossil fuels. However, the resistance to accessibility of sugars embedded in plant cell walls (so-called recalcitrance) is a major barrier to economically viable cellulosic ethanol production. A recent report from the US National Academy of Sciences indicated that, “absent technological breakthroughs”, it was unlikely that the US would meet the congressionally mandated renewable fuel standard of 35 billion gallons of ethanol-equivalent biofuels plus 1 billion gallons of biodiesel by 2022. We here describe the properties of switchgrass ( Panicum virgatum ) biomass that has been genetically engineered to increase the cellulosic ethanol yield by more than 2-fold. We have increased the cellulosic ethanol yield from switchgrass by 2.6-fold through overexpression of the transcription factor PvMYB4. This strategy reduces carbon deposition into lignin and phenolic fermentation inhibitors while maintaining the availability of potentially fermentable soluble sugars and pectic polysaccharides. Detailed biomass characterization analyses revealed that the levels and nature of phenolic acids embedded in the cell-wall, the lignin content and polymer size, lignin internal linkage levels, linkages between lignin and xylans ectins, and levels of wall-bound fucose are all altered in PvMYB4-OX lines. Genetically engineered PvMYB4-OX switchgrass therefore provides a novel system for further understanding cell wall recalcitrance. Our results have demonstrated that overexpression of PvMYB4, a general transcriptional repressor of the phenylpropanoid/lignin biosynthesis pathway, can lead to very high yield ethanol production through dramatic reduction of recalcitrance. MYB4-OX switchgrass is an excellent model system for understanding recalcitrance, and provides new germplasm for developing switchgrass cultivars as biomass feedstocks for biofuel production.
Publisher: Informa UK Limited
Date: 21-01-2020
Publisher: American Chemical Society (ACS)
Date: 13-04-2012
DOI: 10.1021/JP2122449
Abstract: Lignin is a complex, heterogeneous polymer in plant cell walls that provides mechanical strength to the plant stem and confers resistance to degrading microbes, enzymes, and chemicals. Lignin synthesis initiates through oxidative radical-radical coupling of monolignols, the most common of which are p-coumaryl, coniferyl, and sinapyl alcohols. Here, we use density functional theory to characterize radical-radical coupling reactions involved in monolignol dimerization. We compute reaction enthalpies for the initial self- and cross-coupling reactions of these monolignol radicals to form dimeric intermediates via six major linkages observed in natural lignin. The 8-O-4, 8-8, and 8-5 coupling are computed to be the most favorable, whereas the 5-O-4, 5-5, and 8-1 linkages are less favorable. Overall, p-coumaryl self- and cross-coupling reactions are calculated to be the most favorable. For cross-coupling reactions, in which each radical can couple via either of the two sites involved in dimer formation, the more reactive of the two radicals is found to undergo coupling at its site with the highest spin density.
Publisher: The University of Sydney Library
Date: 02-12-2021
DOI: 10.30722/IJISME.29.02.003
Abstract: The introduction of Indigenous knowledges (IK) and perspectives to the curriculum is an important step in decolonising the curriculum, and in reconciliation. This study explored the impact of a short laboratory project in the context of a traditional Aboriginal remedy (bush medicine), on final year Analytical Chemistry students. S les were taken from the Sandpaper fig both off- and on-country, and students designed their own investigation to determine whether the chemicals present differed with location. The activity required no dedicated cultural awareness training, and did not involve student interaction with an Indigenous academic. A video made by one of the authors supported the students’ cultural learning and understanding. The findings indicate that the students displayed a respectful consideration of IK and Indigenous perspectives. However, the students’ inherent aversion to the idea of combining Indigenous and non-Indigenous knowledges, meant that they did not effectively bring Indigenous perspectives to bear within their own investigation. Students believed that the inclusion of Indigenous methods of inquiry in a modern laboratory setting made the IK feel inauthentic. We provide recommendations for more structured approaches to learning when integrating IK erspectives and Western Scientific practices to allow students to comfortably navigate through IK within a modern context.
Publisher: Springer Science and Business Media LLC
Date: 27-08-2015
Publisher: Oxford University Press (OUP)
Date: 07-02-2013
Abstract: Grass cell wall properties influence food, feed, and biofuel feedstock usage efficiency. The glucuronoarabinoxylan of grass cell walls is esterified with the phenylpropanoid-derived hydroxycinnamic acids ferulic acid (FA) and para-coumaric acid (p-CA). Feruloyl esters undergo oxidative coupling with neighboring phenylpropanoids on glucuronoarabinoxylan and lignin. Examination of rice (Oryza sativa) mutants in a grass-expanded and - erged clade of BAHD acyl-coenzyme A-utilizing transferases identified four mutants with altered cell wall FA or p-CA contents. Here, we report on the effects of overexpressing one of these genes, OsAt10 (LOC_Os06g39390), in rice. An activation-tagged line, OsAT10-D1, shows a 60% reduction in matrix polysaccharide-bound FA and an approximately 300% increase in p-CA in young leaf tissue but no discernible phenotypic alterations in vegetative development, lignin content, or lignin composition. Two additional independent OsAt10 overexpression lines show similar changes in FA and p-CA content. Cell wall fractionation and liquid chromatography-mass spectrometry experiments isolate the cell wall alterations in the mutant to ester conjugates of a five-carbon sugar with p-CA and FA. These results suggest that OsAT10 is a p-coumaroyl coenzyme A transferase involved in glucuronoarabinoxylan modification. Biomass from OsAT10-D1 exhibits a 20% to 40% increase in saccharification yield depending on the assay. Thus, OsAt10 is an attractive target for improving grass cell wall quality for fuel and animal feed.
Publisher: Springer Science and Business Media LLC
Date: 12-02-2018
DOI: 10.1038/NBT.4067
Abstract: Cell walls in crops and trees have been engineered for production of biofuels and commodity chemicals, but engineered varieties often fail multi-year field trials and are not commercialized. We engineered reduced expression of a pectin biosynthesis gene (Galacturonosyltransferase 4, GAUT4) in switchgrass and poplar, and find that this improves biomass yields and sugar release from biomass processing. Both traits were maintained in a 3-year field trial of GAUT4-knockdown switchgrass, with up to sevenfold increased saccharification and ethanol production and sixfold increased biomass yield compared with control plants. We show that GAUT4 is an α-1,4-galacturonosyltransferase that synthesizes homogalacturonan (HG). Downregulation of GAUT4 reduces HG and rhamnogalacturonan II (RGII), reduces wall calcium and boron, and increases extractability of cell wall sugars. Decreased recalcitrance in biomass processing and increased growth are likely due to reduced HG and RGII cross-linking in the cell wall.
Publisher: Springer Science and Business Media LLC
Date: 06-2016
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.BMCL.2007.10.090
Abstract: A series of novel 2-alkoxy- and 2-aryloxyiminoalkyl trifluoromethanesulfonanilide derivatives have shown significant in vitro parasiticidal activity against the ectoparasites Ctenocephalides felis and Rhipicephalus sanguineus. A number of these compounds also displayed significant in vitro endoparasite activity against the nematode Haemonchus contortus.
Publisher: Wiley
Date: 24-02-2023
DOI: 10.1002/ASE.2174
Abstract: Uncertainty tolerance, in iduals' perceptions/responses to uncertain stimuli, is increasingly recognized as critical to effective healthcare practice. While the Covid‐19 pandemic generated collective uncertainty, healthcare‐related uncertainty is omnipresent. Correspondingly, there is increasing focus on uncertainty tolerance as a health professional graduate “competency,” and a concomitant interest in identifying pedagogy fostering learners' uncertainty tolerance. Despite these calls, practical guidelines for educators are lacking. There is some initial evidence that anatomy education can foster medical students' uncertainty tolerance (e.g., anatomical variation and dissection novelty), however, there remains a knowledge gap regarding robust curriculum‐wide uncertainty tolerance teaching strategies. Drawing upon humanities, arts and social sciences (HASS) educators' established uncertainty tolerance pedagogies, this study sought to learn from HASS academics' experiences with, and teaching practices related to, uncertainty pedagogy using a qualitative, exploratory study design. Framework analysis was undertaken using an abductive approach, wherein researchers oscillate between inductive and deductive coding (comparing to the uncertainty tolerance conceptual model). During this analysis, the authors analyzed ~386 min of data from purposively s led HASS academics' ( n = 14) discussions to address the following research questions: (1) What teaching practices do HASS academics' perceive as impacting learners' uncertainty tolerance, and (2) How do HASS academics execute these teaching practices? The results extend current understanding of the moderating effects of education on uncertainty tolerance and supports prior findings that the anatomy learning environment is ripe for supporting learner uncertainty tolerance development. This study adds to growing literature on the powerful moderating effect education has on uncertainty tolerance and proposes translation of HASS uncertainty tolerance teaching practices to enhance anatomy education.
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/B003527K
Publisher: Springer Science and Business Media LLC
Date: 17-01-2018
Publisher: Oxford University Press (OUP)
Date: 27-06-2014
Publisher: Springer Science and Business Media LLC
Date: 20-10-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7RP00233E
Abstract: Many ex les exist in the chemical education literature of in idual experiments, whole courses or even entire year levels that have been completely renewed under the tenets of context-based, inquiry-based or problem-based learning. The benefits of these changes are well documented and include higher student engagement, broader skill development and better perceived preparation for the workforce. However, no ex les appear to have been reported in which an entire school's teaching laboratory programme has been significantly redesigned with these concepts in mind. Transforming Laboratory Learning (TLL) is a programme at Monash University that sought to incorporate industry inspired context-based, inquiry-based and problem-based learning into all the laboratory components of the School of Chemistry. One of the ways in which the effect of the programme was evaluated was through the use of an exit survey delivered to students at the completion of seven experiments that existed before the TLL programme as well as seven that were generated directly by the TLL programme. The survey consisted of 27 closed questions alongside three open questions. Overall, students found the new experiments more challenging but recognised that they were more contextualised and that they allowed students to make decisions. The students noted the lack of detailed guidance in the new laboratory manuals but raised the challenge, context and opportunity to undertake experimental design as reasons for enjoying the new experiments. Students' perceptions of their skill development shifted to reflect skills associated with experimental design when undertaking the more investigation driven experiments. These results are consistent with other literature and indicate the large scale potential success of the TLL programme, which is potentially developing graduates who are better prepared for the modern workforce.
Publisher: Springer Science and Business Media LLC
Date: 12-03-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8RP00188J
Abstract: How students behave and learn in the teaching laboratory is a topic of great interest in chemical education, partly in order to justify the great expense of teaching laboratories. Much effort has been put into investigating how students think, feel and physically act in these unique learning environments. One such attempt was made through the generation and utilisation of the Meaningful Learning in the Laboratory Instrument (MLLI). This 30 question survey utilised Novak's theory of Meaningful Learning to investigate the affective, cognitive and psychomotor domains of the student learning experience. To date, this survey has been used to great effect to measure how students’ perception of their own feelings and actions will change over the course of a semester. This study reports the use of a modified MLLI survey to probe how the expectations of students change over their undergraduate degree. To increase the generalisability of the outcomes of the study data was gathered from four universities from Australia (Monash University, the University of New South Wales and the University of Sydney) and the UK (the University of Warwick). Students were found to start their university careers with very positive expectations of their teaching laboratory experiences. Their outlook became somewhat more negative each year that they were enrolled in the program. A further modified MLLI survey was presented to teaching associates and academic staff. Teaching staff were shown to have far more negative expectations of the students’ feelings and actions, with academic staff more likely to believe that students do not undertake many items of positive meaningful learning. Overall, this study highlights the large gap between the expectations of teaching staff and students which, if left unaddressed, will likely continue to cause great frustration for both teaching staff and students.
Publisher: Wiley
Date: 30-12-2011
DOI: 10.1002/EP.10628
Publisher: Humana Press
Date: 2012
DOI: 10.1007/978-1-61779-956-3_17
Abstract: Cell wall recalcitrance is the largest contributor to the high expense of lignocellulose conversion to biofuels (Himmel ME et al., Science 315:804-807, 2007). In response to this problem, researchers at the BioEnergy Science Center (BESC) are working to determine the contributing factors of biomass recalcitrance. The primary approach to this is screening large s le sets of genetic and environmental variants of model and feedstock plant species for differences in recalcitrance to combined hydrothermal pretreatment and enzymatic hydrolysis (Decker S et al., BioEnergy Res 2:179-192, 2009). To handle these large s le sets (up to several thousand s les per set), the BESC has developed high throughput screening systems to evaluate both cell wall composition and recalcitrance (Selig MJ et al., Biotechnol Lett 33:961-967, 2011 Selig MJ et al., Ind Biotechnol 6, 104-111, 2010). Molecular beam mass spectroscopy and high throughput, 2-stage acid hydrolysis are used to determine amounts and ratios of cell wall components such as lignin, cellulose, and xylan. Recalcitrance is measured by glucose and xylose release after high throughput hydrothermal pretreatment and enzymatic saccharification, screening large numbers (up to 1,000 s per week) of biomass s les (Selig MJ et al., Ind Biotechnol 6, 104-111, 2010 Sykes R et al., Methods Mol Biol 581, 169-183, 2009). Implementation of these high throughput techniques revealed additional concerns when screening biomass s les for recalcitrance, principal among these was the contribution of starch to glucose release quantitation in both compositional analysis and recalcitrance screening.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7RP00177K
Abstract: The aims of teaching laboratories is an important and ever-evolving topic of discussion amongst teaching staff at teaching institutions. It is often assumed that both teaching staff and students are implicitly aware of these aims, although this is rarely tested or measured. This assumption can lead to mismatched beliefs between students and teaching staff and, if not corrected for, could lead to negative learning gains for students and become a source of frustration for teaching staff. In order to measure and identify this gap in a manner that could be readily generalised to other institutions, a single open question – ‘What do you think the aims of doing a practical chemistry course are?’ – was distributed to students and teaching staff at two Australian universities and one UK university. Qualitative analysis of the responses revealed that students and teaching staff held relatively narrow views of teaching laboratories, particularly focusing on aims more in line with expository experiences ( e.g. development of practical skills or enhances understanding of theory). Whilst some differences were noted between students at the three institutions, the large amount of similarities in their responses indicated a fairly common perception of laboratory aims. Of the three groups, academics actually held the narrowest view of teaching laboratories, typically neglecting the preparation of students for the workforce or the simple increase in laboratory experience the students could gain. This study highlights gaps between the perceptions of students and teaching staff with regards to laboratory aims alongside revealing that all three groups held relatively simplified views of teaching laboratories.
Publisher: Elsevier BV
Date: 12-2010
Location: United States of America
No related grants have been discovered for Angela Ziebell.