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0000-0002-9963-5924
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University of Wollongong
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Organometallic Chemistry | Physical Organic Chemistry | Catalysis and Mechanisms of Reactions | Organic Chemistry | Organic Chemical Synthesis | Physical Chemistry (Incl. Structural)
Publisher: American Chemical Society (ACS)
Date: 16-06-2023
Publisher: Elsevier BV
Date: 02-2010
DOI: 10.1016/J.VETPAR.2009.08.028
Abstract: The temporal association between the periparturient rise (PPR) in worm egg count (WEC) of grazing Merino ewes to infection with Trichostrongylus colubriformis and the underlying causal mechanisms was investigated in an experiment that incorporated two levels of pregnancy (pregnant or unmated), two levels of infection (infected with 6000 T. colubriformis L(3)/week or uninfected) and, following lambing, three levels of lactation (non-lactating/"dry", early-weaned 2 days after parturition, or suckled). The 128 ewes in the experiment were monitored for a range of parasitological and host systemic and local immune responses from days -50 to 42, relative to the midpoint of lambing (day 0). Unmated/non-lactating (dry) ewes remained largely resistant to T. colubriformis infection with WEC remaining below 200 eggs per gram (epg) throughout the experiment. For infected ewes, the PPR in WEC commenced during late pregnancy and peaked at 1552epg on day 42. There was evidence of a relaxation of immunity that preceded the rise, as demonstrated by a reduction in circulating eosinophils and plasma total antibody (Tab) and lower titres of Tab and IgG(1) in the small intestine in pregnant ewes. Circulating eosinophils and plasma Tab remained low in suckled ewes, and at the local level, lactating ewes also had lower titres of Tab, IgG(1), IgM, IgA and IgE as well as fewer mast cells (MC), globule leucocytes (GL) and goblet cells (GC) in intestinal tissue. These effects were associated with higher worm burdens. Weaning at 2 days after lambing resulted in a rapid amelioration of immunological responsiveness and a reduction in WEC, worm burden and parasite establishment rate. A rapid increase in circulating eosinophils and Tab titre followed by an improvement in components of the local immune response was also observed. Over the 6-week period following lambing, weaned ewes exhibited higher titres of Tab, IgG(1), IgM, IgA and IgE as well as higher numbers of MC, GL and GC present in the small intestinal tissue, compared to lactating ewes. The results provide a detailed characterisation of the periparturient relaxation of immunity to T. colubriformis, and highlight possible causative factors that deserve further investigation.
Publisher: American Chemical Society (ACS)
Date: 02-11-2010
DOI: 10.1021/IC1020912
Abstract: Ligand effects in bimetallic high oxidation state systems containing a X-Pd-Pd-Y framework have been explored with density functional theory (DFT). The ligand X has a strong effect on the dissociation reaction of Y to form [X-Pd-Pd](+) + Y(-). In the model system examined where Y is a weak σ-donor ligand and a good leaving group, we find that dissociation of Y is facilitated by greater σ-donor character of X relative to Y. We find that there is a linear correlation of the Pd-Y and Pd-Pd bond lengths with Pd-Y bond dissociation energy, and with the σ-donating ability of X. These results can be explained by the observation that the Pd d(z(2)) population in the PdY fragment increases as the donor ability of X increases. In these systems, the Pd(III)-Pd(III) arrangement is favored when X is a weak σ-donor ligand, while the Pd(IV)-Pd(II) arrangement is favored when X is a strong σ-donor ligand. Finally, we demonstrate that ligand exchange to form a bimetallic cationic species in which each Pd is six-coordinate should be feasible in a high polarity solvent.
Publisher: Wiley
Date: 21-12-2019
Publisher: Wiley
Date: 26-07-2022
Publisher: Oxford University Press (OUP)
Date: 07-2006
DOI: 10.1093/NAR/GKL196
Publisher: Elsevier
Date: 2017
Publisher: Georg Thieme Verlag KG
Date: 18-01-2017
Publisher: Elsevier BV
Date: 02-2010
DOI: 10.1016/J.VETPAR.2009.12.012
Abstract: The temporal association between the periparturient rise in worm egg count of grazing Merino ewes to infection with Trichostrongylus colubriformis and the underlying causal mechanisms was investigated in an experiment that incorporated two levels of pregnancy (pregnant or unmated), two levels of infection (infected with 6000 T. colubriformis L(3)/week or uninfected) and, following lambing, three levels of lactation (non-lactating/"dry", early-weaned 2 days after parturition, or suckled). In addition to parasitological and host immune responses reported in a previous paper (Beasley et al., 2010), a range of endocrine and body compositional changes were monitored from day -50 to day 42, relative to the midpoint of lambing (day 0). By day -19, pregnant ewes had begun to mobilise fat and eye muscle, and after 42 days of suckling had lost 31% and 8%, respectively, of their existing depots. In comparison to non-pregnant (dry) ewes, the endocrine profiles of late-pregnant ewes were characterised by low levels of cortisol and prolactin and high levels of progesterone and oestradiol. Lactating ewes had lower levels of cortisol and leptin and higher levels of prolactin compared to both dry and early-weaned ewes. The mobilisation of fat and protein reserves throughout lactation in suckled ewes was closely associated with leptin and cortisol profiles, and provided strong evidence of an underlying nutritional basis for the periparturient relaxation of immunity. Both leptin and cortisol concentrations were also associated with both parasite burden and the immune status of the ewe. It is suggested that lower blood cortisol levels in suckled ewes contribute to a Th1 biased immune response that leads to an increased susceptibility to gastrointestinal nematodes. The results provide a detailed characterisation of the physiology underlying the periparturient relaxation of immunity to T. colubriformis, from which further investigations will aim to expose potential causal factors.
Publisher: Elsevier
Date: 2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0OB01046D
Abstract: TiCl(4) and TiBr(4) rapidly transform cyclopropenylmethyl acetates to (E)-halodienes via ring-opening to allyl-vinyl cations. DFT calculations suggest that the regioselectivity of the halogenation of this cationic intermediate by [TiX(4)OAc](-) is under thermodynamic control, while the stereoselectivity is governed by kinetics.
Publisher: Wiley
Date: 22-10-2015
Publisher: Elsevier
Date: 2016
Publisher: Elsevier BV
Date: 11-2007
Abstract: With the completion of sequencing projects for several parasite genomes, efforts are ongoing to make sense of this mass of information in terms of the gene products encoded and their interactions in the growth, development and survival of parasites. The emerging science of systems biology aims to explain the complex relationship between genotype and phenotype by using network models. One area in which this approach has been particularly successful is in the modeling of metabolism. With an accurate picture of the set of metabolic reactions encoded in a genome, it is now possible to identify enzymes or transporters that might be viable targets for new drugs. Because these predictions greatly depend on the quality and completeness of the genome annotation, there are substantial efforts in the scientific community to increase the numbers of metabolic enzymes identified. In this review, we discuss the opportunities for using metabolic reconstruction and analysis tools in parasitology research, and their applications to protozoan parasites.
Publisher: Informa UK Limited
Date: 11-06-2013
Publisher: Elsevier
Date: 2021
Publisher: American Chemical Society (ACS)
Date: 14-06-2011
DOI: 10.1021/IC102323S
Abstract: Reductive elimination of C-Cl and C-C bonds from binuclear organopalladium complexes containing Pd-Pd bonds with overall formal oxidation state +III are explored by density functional theory for dichloromethane and acetonitrile solvent environments. An X-ray crystallographically authenticated neutral complex, [(L-C,N)ClPd(μ-O(2)CMe)](2) (L = benzo[h]quinolinyl) (I), is examined for C-Cl coupling, and the proposed cation, [(L-C,N)PhPd(1)(μ-O(2)CMe)(2)Pd(2)(L-C,N)](+) (II), examined for C-C coupling together with (L-C,N)PhPd(1)(μ-O(2)CMe)(2)Pd(2)Cl(L-C,N) (III) as a neutral analogue of II. In both polar and nonpolar solvents, reaction from III via chloride dissociation from Pd(2) to form II is predicted to be favored. Cation II undergoes Ph-C coupling at Pd(1) with concomitant Pd(1)-Pd(2) lengthening and shortening of the Pd(1)-O bond trans to the carbon atom of L natural bond orbital analysis indicates that reductive coupling from II involves depopulation of the d(x(2)-y(2)) orbital of Pd(1) and population of the d(z(2)) orbitals of Pd(1) and Pd(2) as the Pd-Pd bond lengthens. Calculations for the symmetrical dichloro complex I indicate that a similar dissociative pathway for C-Cl coupling is competitive with a direct (nondissociative) pathway in acetonitrile, but the direct pathway is favored in dichloromethane. In contrast to the dissociative mechanism, direct coupling for I involves population of the d(x(2)-y(2)) orbital of Pd(1) with Pd(1)-O(1) lengthening, significantly less population occurs for the d(z(2)) orbital of Pd(1) than for the dissociative pathway, and d(z(2)) at Pd(2) is only marginally populated resulting in an intermediate that is formally a Pd(1)(I)-Pd(2)(III) species, (L-Cl-N,Cl)Pd(1)(μ-O(2)CMe)Pd(2)Cl(O(2)CMe)(L-C,N) that releases chloride from Pd(2) with loss of Pd(I)-Pd(III) bonding to form a Pd(II) species. A similar process is formulated for the less competitive direct pathway for C-C coupling from III, in this case involving decreased population of the d(z(2)) orbital of Pd(2) and strengthening of the Pd(I)-Pd(III) interaction in the analogous intermediate with η(2)-coordination at Pd(1) by L-Ph-N, C(1)-C(2).
Publisher: Wiley
Date: 08-2006
Publisher: Wiley
Date: 29-11-2005
Publisher: Wiley
Date: 16-01-2019
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.VPRSR.2017.03.009
Abstract: The macrocyclic lactone (ML) drugs are central to the control of equine strongyles but recent international reports raise concerns about reduced efficacy of these drugs against cyathostomins. The objectives of the present study were firstly, to evaluate the efficacy of ML drugs against cyathostomins on a cross-section of Australian horse farms, and secondly, to determine the egg reappearance period (ERP) following treatment of horses with MLs. A total of 419 horses on 43 properties were treated orally with ivermectin, abamectin or moxidectin, at recommended dose rates and drug efficacy was determined using the faecal egg count reduction test. Efficacy of 100% at 14days post-treatment was reported on all of the 43 farms. ERP following ivermectin treatment was 6weeks on two properties and ERP following moxidectin treatment was 12weeks on a third property. These ERPs are shorter than those reported at the time of commercial release of these drugs which likely reflects changing drug susceptibility of the cyathostomin populations tested. Ongoing surveillance of drug efficacy and ERPs should be part of an integrated management approach to equine worm control that prioritises the preservation of anthelmintic efficacy.
Publisher: American Chemical Society (ACS)
Date: 12-11-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6OB90061E
Abstract: Correction for ‘Oxidative ring-opening of ferrocenylcyclopropylamines to N -ferrocenylmethyl β-hydroxyamides’ by Yi Sing Gee et al. , Org. Biomol. Chem. , 2016, 14 , 2498–2503.
Publisher: Wiley
Date: 19-07-2005
Publisher: CSIRO Publishing
Date: 13-04-2022
DOI: 10.1071/AN21509
Abstract: Context High international demand for goat meat and high prices for goat in Australia have resulted in a transition from opportunistic harvesting to more managed production systems for Rangeland goats. There is limited information available to establish feeding strategies to maximise growth rates of Rangeland goats within these developing managed production systems. Aims The aim of these experiments was to determine the response to supplements and the metabolisable energy requirements for maintenance and liveweight gain of young entire male Rangeland goats. Methods Dose–response relationships to various supplements were established in two experiments with young entire male Rangeland goats. In Experiment 1, 54 goats were allocated to rolled-wheat grain, rolled-sorghum grain, or lucerne pellet supplements offered from 0 (control) to 24 g dry matter/kg liveweight.day. In Experiment 2, 24 goats were allocated to a commercial starch-based pellet offered from 0 (control) to ad libitum. In both experiments, goats were held in in idual pens and offered their daily supplement allowances with ad libitum access to Mitchell grass hay and drinking water for 70 days. Key results Total intake (30 to 32 g dry matter/kg liveweight.day) increased in a linear fashion with an increasing intake of all supplements. Maximum intake of rolled-wheat, rolled-sorghum, lucerne pellets and the commercial starch-based pellet supplements ranged from 18 to 22 g dry matter/kg liveweight.day. Unsupplemented goats lost liveweight (−20 to −32 g/day), while supplemented goats gained liveweight (0 to 126 g/day) in a linear fashion with an increasing supplement and metabolisable energy intake for all supplements, with the highest response in goats supplemented with the commercial starch-based pellets. Estimated metabolisable energy requirements to maintain liveweight (372 kJ/kg liveweight0.75.day) and for liveweight gain (35 kJ/g) of the goats were the same in both experiments. Conclusion Liveweight gain increased in a linear fashion with metabolisable energy intake, with the maximum rates of liveweight gain occurring when starch-based supplement intake was approximately 20 g dry matter/kg liveweight.day. Implications Supplementation with starch-based rations will increase liveweight gain and decrease age at turn-off of young entire male Rangeland goats however, the local availability and cost of these supplements need to be considered.
Publisher: American Chemical Society (ACS)
Date: 03-06-2021
Publisher: IGI Global
Date: 07-2016
Abstract: The aim of this study was to gather university student perspectives on a new type of assessment task requesting them to create “blended media”. Blended media is a new form of student-generated multimedia whereby students devise a narration or voiceover to explain a science concept complemented by any combination of visuals such as video, animation or still images that are original or created by others to enhance the explanation. In the assessment task all the students successfully made a blended media product in their own time using their own technology and only requiring one session of media instruction. Surprisingly, the three case students who volunteered to be interviewed stated that they had never made a media product for a science assignment before and enjoyed creating this new form of assignment because they found it engaging and interesting. It also required them to represent content in new ways. Blended media is an innovative way for students to make digital media that engages them with content and as an assessment task could be used in any subject.
Publisher: Elsevier BV
Date: 04-2005
Publisher: Wiley
Date: 22-09-2016
Publisher: American Chemical Society (ACS)
Date: 27-04-2021
Publisher: Wiley
Date: 17-01-2019
Abstract: A synthesis of unconjugated (E)-enediynes from allenyl amino alcohols is reported and their gold-catalyzed cascade cycloaromatization to a broad range of enantioenriched substituted isoindolinones has been developed. Experimental and computational studies support the reaction proceeding via a dual-gold σ,π-activation mode, involving a key gold-vinylidene- and allenyl-gold-containing intermediate.
Publisher: Elsevier
Date: 2012
Publisher: Wiley
Date: 27-06-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4OB01786B
Abstract: The palladium( ii )-catalysed addition of arylboronic acids to vinylaziridines has been developed. This reaction proceeds via an insertion/ring-opening process to provide ( E )-allylsulfonamides. This stereoselectivity is complimentary to existing methods that typically proceed via an S N 2′ mechanism to yield ( Z )-allylic systems.
Publisher: Royal Society of Chemistry (RSC)
Date: 1973
DOI: 10.1039/P29730001402
Publisher: Walter de Gruyter GmbH
Date: 2006
Abstract: An efficient synthesis of α-aminoallenylstannane from propargyloxazolidinone has been developed. It undergoes reaction with aldehydes to give homopropargylic alcohols with high syn selectivity. Epoxides undergo a similar reaction preceded by rearrangement to the aldehyde. These alcohols were used in the synthesis of β-amino acids, azasugars, and deoxyaminohexoses. Imines underwent reaction with this stannane to give 1,2-diamines. The related propargylborane reacts with aldehydes to produce allenyl carbinols. The Co 2 (CO) 6 complexes of propargyloxazolidinones were developed as an α-aminopropargyl cation equivalent.
Publisher: Wiley
Date: 17-08-2023
Abstract: The crotylation reactions of chiral α‐F, α‐OBz and α‐OH aldehydes under Petasis‐borono‐Mannich conditions using ( E )‐ or ( Z )‐crotylboronates and primary amines resulted in γ‐addition products in high dr and high er. α‐F and α‐OBz aldehydes gave 1,2‐ anti ‐2,3‐ syn and 1,2‐ anti ‐2,3‐ anti , products, respectively while an α‐OH aldehyde gave 1,2‐ syn ‐2,3‐ syn products. The stereochemical outcomes of reactions of the former aldehydes can be explained using a six‐membered ring transition state (TS) model in which a Cornforth‐like conformation around the imine intermediate is favoured resulting in 1,2‐ anti products. The 2,3‐stereochemical outcome is dependent upon the geometry of the crotylboronate. These TS models were also supported by DFT calculations. The stereochemical outcomes of reactions employing an α‐OH aldehyde can be rationalised as occurring via an open‐TS involving H‐bonding in the imine intermediate between the α‐OH group and the imine N atom. Representative products were converted to highly functionalized 1,2,3,6‐tetrahydropyridines and 3 H ‐oxazolo[3,4‐ a ]pyridine‐3‐ones which will be valuable scaffolds in synthesis.
Publisher: American Chemical Society (ACS)
Date: 27-01-2021
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.EJMECH.2013.05.007
Abstract: A whole organism high-throughput screen of approximately 87,000 compounds against Trypanosoma brucei brucei led to the recent discovery of several novel compound classes with low micromolar activity against this organism and without appreciable cytotoxicity to mammalian cells. Herein we report a structure-activity relationship (SAR) investigation around one of these hit classes, the 3-(oxazolo[4,5-b]pyridin-2-yl)anilides. Sharp SAR is revealed, with our most active compound (5) exhibiting an IC₅₀ of 91 nM against the human pathogenic strain T.b. rhodesiense and being more than 700 times less toxic towards the L6 mammalian cell line. Physicochemical properties are attractive for many compounds in this series. For the most potent representatives, we show that solubility and metabolic stability are key parameters to target during future optimisation.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0MD00277A
Abstract: African sleeping sickness is a potentially fatal neglected disease affecting sub-Saharan Africa.
Publisher: Wiley
Date: 28-03-2013
Publisher: American Chemical Society (ACS)
Date: 14-06-2017
Abstract: The simultaneous control of diastereoselectivity and regioselectivity in Zn-catalyzed allenylation reactions of N-protected l-α-amino aldehydes is reported. A reversal in diastereoselectivity could be realized by variation of the α-amino aldehyde protecting groups. A range of 1-allenyl-2-amino alcohols were obtained with excellent regioselectivity and converted to oxazolidinones and dihydrofurans. Many of which could be isolated as single diastereoisomers and without significant erosion of ee, making this a practical catalytic synthesis of highly functionalized heterocycles.
Publisher: Wiley
Date: 09-09-2014
Publisher: American Chemical Society (ACS)
Date: 15-11-2021
DOI: 10.26434/CHEMRXIV-2021-N9HRB
Abstract: Density functional theory (DFT) is used in this work to predict the mechanism for constructing congested quaternary-quaternary carbon(sp3)–carbon(sp3) bonds in a pentanidium catalyzed substitution reaction. Computational mechanistic studies were carried out to investigate the proposed SN2X manifold, which consists of two primary elementary steps: halogen atom transfer (XAT) and subsequent SN2. For the first calculated model on original experimental substrates, XAT reaction barriers were more kinetically competitive than an SN2 pathway and connects to thermodynamically stable intermediates. Extensive computational screening-modelling were then done on various substrate combinations designed to study steric influence and to understand the mechanistic rationale, and calculations reveal that sterically congested substrates prefer the SN2X manifold over SN2. Different halides as leaving groups were also screened and it was found that the reactivity increases in order of Br Cl F in agreement of the strength of C–X bonds. However, DFT modelling suggests that chlorides can be a viable substrate for the SN2X process which should be further explored experimentally. Finally, ONIOM calculations on the full catalyst model were carried out to rationalize the stereoselectivity which corroborates with experimental results.
Publisher: Royal Society of Chemistry (RSC)
Date: 2002
DOI: 10.1039/C5OB02577J
Abstract: The in situ reduction of ferrocenyl cyclopropylimines to the corresponding amines triggers a facile oxidative ring-opening to yield the formal four-electron oxidation products: N -ferrocenylmethyl β-hydroxyamides.
Publisher: Elsevier
Date: 2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5MD00174A
Abstract: This review summarises recent developments in the search for novel organometallic drug compounds for the treatment of neglected tropical diseases.
Publisher: Wiley
Date: 11-12-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7RA11711F
Abstract: A synthesis of thiourea-bridged mesoporous organosilica is reported.
Publisher: Springer Science and Business Media LLC
Date: 03-09-2021
DOI: 10.1186/S13071-021-04966-1
Abstract: Strongyloides westeri is found in the small intestine of young horses, mainly in foals up to about 16 weeks of age. The main source of infection for foals is through transmammary transmission, and foals can develop acute diarrhoea, weakness, dermatitis and respiratory signs. The epidemiology of S. westeri in Australia is largely unknown. Further, molecular techniques have never been employed for detection of S. westeri in horses. This pilot study aimed to assess the utility of a molecular phylogenetic method for the detection of S. westeri in the faeces of foals. Faecal s les were collected from a foal of less than 2 months of age, and eggs of Strongyloides sp. were detected using the modified McMaster technique. DNA was extracted from purified eggs, and a partial fragment of the small subunit of the nuclear ribosomal DNA (18S) was characterised using polymerase chain reaction, DNA sequencing and phylogenetic methods. Microscopic examination of faeces revealed small ellipsoidal eggs typical of Strongyloides sp. The 18S sequence generated by PCR in this study revealed 98.4% identity with that of a reference sequence of S. westeri available from GenBank. Phylogenetic analyses revealed a polyphyletic clustering of S. westeri sequences. This is the first study reporting the detection of DNA of Strongyloides sp. in faeces of a foal using a molecular phylogenetic approach targeting the variable region of 18S rDNA. It is anticipated that this study will allow future molecular epidemiological studies on S. westeri in horses.
Publisher: Elsevier
Date: 2013
Publisher: Wiley
Date: 25-10-2023
Publisher: Elsevier
Date: 2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1OB00836F
Abstract: By examining the various contributions to the conformational and stereogenic stability of medium-sized benzo-fused N-heterocyclic atropisomers, this review serves to aid the design, synthesis and study of these pharmaceutically relevant heterocycles.
Publisher: Wiley
Date: 27-02-2007
Publisher: Wiley
Date: 27-08-2015
DOI: 10.1111/AVJ.12352
Abstract: There have been several international reports of macrocyclic lactone (ML)-resistant Parascaris equorum over the past decade, but the resistance status of Australian P. equorum populations is largely unknown. A case of apparent reduced efficacy of ivermectin against P. equorum in Australia was investigated. A faecal egg count reduction test carried out on a group of weanling foals in south-east Queensland showed the efficacy of ivermectin to be 65%. The case highlights the need to review current worm control strategies, especially for young horses.
Publisher: American Chemical Society (ACS)
Date: 07-05-2015
Abstract: We report a highly efficient ring-opening reaction of vinylcyclopropanes by boronic acids in water, using palladium nanoparticles formed from Pd(OAc)2 under ligandless conditions. Unsubstituted vinylcyclopropanes provide linear addition products with high selectivity, while a switch in regioselectivity to branched products is observed for aryl-substituted vinylcyclopropanes.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3OC90011H
Publisher: American Chemical Society (ACS)
Date: 04-01-2017
Publisher: Wiley
Date: 21-12-2019
Publisher: Elsevier
Date: 2021
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.VETPAR.2017.08.010
Abstract: The use of macrocyclic lactone drugs for control of equine cyathostomins is threatened by increasing levels of resistance. Detection of changes in drug sensitivity is important for effective and sustainable management of cyathostomins, however, at present such detection relies on the use of the faecal egg count reduction test, which is known to be an insensitive method. The present study therefore aimed to examine the use of a 96-well plate larval migration inhibition test for detection of resistance to macrocyclic lactone drugs in cyathostomins. We optimised conditions for migration of larvae, and examined the effects of larval storage time on drug dose responses. The modified test was able to define the sensitivity of cyathostomin isolates to ivermectin and eprinomectin in terms of dose response curves, and IC
Publisher: Wiley
Date: 19-03-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SC03215K
Abstract: The first reported catalytic reactivity of 5-allenyloxazolidinones is the tightly controlled, ergent synthesis of chiral 1,3-dienes or 5-vinyloxazolidinones under Pd(0) catalysis.
Publisher: Royal Society of Chemistry (RSC)
Date: 1972
DOI: 10.1039/C39720000720
Publisher: Elsevier
Date: 2018
Publisher: Wiley
Date: 16-01-2014
Publisher: American Chemical Society (ACS)
Date: 12-06-2019
DOI: 10.1021/ACS.ORGLETT.9B01580
Abstract: Aminobenzaldehydes bearing a pendant 3,5-dinitrophenyl group react thermally with N-substituted α-amino acids to form unprecedented benzoazepine-fused isoindolines. The reaction proceeds via a dearomatization/rearomatization sequence involving an intramolecular (3 + 2)-cycloaddition between the in situ formed azomethine ylide and the dinitroarene. Various glycine derivatives are tolerated as well as branched substrates based on cyclic, α-mono-, and α,α-disubstituted amino acids, giving single diastereomers in many cases. The method is scalable and gives products with a nitro group ready for further manipulation.
Publisher: Elsevier BV
Date: 10-2010
DOI: 10.1016/J.RVSC.2010.02.010
Abstract: Immunoglobulin (Ig) E is actively transported into ovine colostrum. Here we examine the degree of selectivity and the mechanism by which this transfer occurs in sheep. Results indicate that during colostrogenesis in sheep, transfer of immunoglobulins was most selective for IgG1 and IgA followed by IgE, IgM and IgG2. In milk, selectivity was greatest for IgA, followed by IgM, IgE, IgG1 and IgG2. The neonatal Fc receptor (FcRn) and poly immunoglobulin receptor (pIgR) mediate the transport of IgG1 and IgA across the ovine mammary epithelium respectively. In primates and rodents, the low-affinity IgE receptor, Fc epsilonRII, functions to transport IgE across the intestinal epithelium. We therefore investigated the expression of the low-affinity IgE receptor (CD23), pIgR and FcRn transcripts in the ovine mammary gland. The expression profiles of FcRn, pIgR and CD23 mRNA reflected concentrations of their Ig ligands in mammary secretions. These findings suggest a role for CD23 in transport of IgE across the mammary epithelium of sheep.
Publisher: Elsevier
Date: 2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1SC03268B
Abstract: The Pd-catalysed asymmetric allylic alkylation (Pd-AAA) of prochiral enamide anions derived from 5 H -oxathiazole 2,2-dioxides has been developed.
Publisher: SAGE Publications
Date: 25-05-2020
Abstract: This paper reports the use of near infrared and mid-infrared spectroscopy to detect the presence and quantity of eggs of the gastrointestinal nematode Haemonchus contortus in sheep faeces. Haemonchus contortus eggs were quantified in dried, finely ground sheep faeces and in moist, coarsely ground faeces using near infrared and mid-infrared bench top spectrometers and a portable near infrared spectrometer. When Haemonchus contortus eggs were presented without faecal medium, it was found that the wavelength region of 1880–2100 nm was most important for detection. Broad classes of chemical properties found in the near infrared region were identified for dried Haemonchus contortus eggs using a mid-infrared spectrometer. However, when Haemonchus contortus eggs were mixed into the complex matrix of sheep faeces, the development of a robust calibration model for egg detection proved to be challenging (R 2 0.47). The reliability of this method, if used for the detection of Haemonchus contortus eggs in the field, may be further limited by variations in egg species, faecal moisture content, faecal composition and particle size. Nevertheless, this is the first report identifying near infrared bands for Haemonchus contortus eggs and provides valuable information for future studies towards a spectroscopy-based method for detection of gastrointestinal nematodes.
Publisher: Springer Science and Business Media LLC
Date: 04-12-2021
DOI: 10.1186/S13071-021-05103-8
Abstract: Cyathostomins are the most important and common parasitic nematodes of horses, with 50 species known to occur worldwide. The frequent and indiscriminate use of anthelmintics has resulted in the development of anthelmintic resistance (AR) in horse nematodes. In this study we assessed the efficacy of commonly used anthelmintics against cyathostomins in Australian thoroughbred horses. Two drug efficacy trials per farm were conducted on two thoroughbred horse farms in the state of Victoria, Australia. In the first trial, the horses on Farm A were treated with single and combinations of anthelmintics, including oxfendazole (OFZ), abamectin (ABM), abamectin and morantel (ABM + MOR), moxidectin (MOX) and oxfendazole and pyrantel (OFZ + PYR), at the recommended doses, whereas the horses on Farm B only received MOX, at the recommended dose. The faecal egg count reduction test (FECRT) was used to determine the efficacy and egg reappearance period (ERP) of anthelmintics. Based on the results of the first trial, the efficacies of MOX and a combination of ABM + MOR were reassessed to confirm their activities against cyathostomins. Of the five anthelmintic products tested on Farm A, resistance against OFZ, ABM and OFZ + PYR was found, with efficacies of − 41% (− 195% lower confidence limit [LCL]), 73% (60% LCL) and 82% (66% LCL) at 2 weeks post-treatment, respectively. The FECRT showed high efficacies of MOX and ABM + MOR (100%) at 2 week post-treatment and shortened ERPs for these anthelmintics (ABM + MOR: 4 weeks MOX: 5 weeks). Resistance to MOX was found on Farm B, with a reduced efficacy of 90% (70% LCL) and 89% (82% LCL) at 2 weeks post-treatment in trials one and two, respectively. This study provides the first evidence of MOX- and multidrug-resistant (ABM and combinations of anthelmintics) cyathostomins in Australia and indicates the need for continuous surveillance of the efficacy of currently effective anthelmintics and large-scale investigations to assess the ERP for various anthelmintics.
Publisher: Wiley
Date: 27-01-2022
Abstract: Diazo compounds have been largely used as carbene precursors for carbene transfer reactions in a variety of functionalization reactions. However, the ease of carbene generation from the corresponding diazo compounds depends upon the electron donating/withdrawing substituents either side of the diazo functionality. These groups strongly impact the ease of N 2 release. Recently, tris(pentafluorophenyl)borane [B(C 6 F 5 ) 3 ] has been shown to be an alternative transition metal‐free catalyst for carbene transfer reactions. Herein, a density functional theory (DFT) study on the generation of carbene species from α‐aryl α‐diazocarbonyl compounds using catalytic amounts of B(C 6 F 5 ) 3 is reported. The significant finding is that the efficiency of the catalyst depends directly on the nature of the substituents on both the aryl ring and the carbonyl group of the substrate. In some cases, the boron catalyst has negligible effect on the ease of the carbene formation, while in other cases there is a dramatic reduction in the activation energy of the reaction. This direct dependence is not commonly observed in catalysis and this finding opens the way for intelligent design of this and other similar catalytic reactions.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0OB01568G
Abstract: Five-membered ring cyclic sulfamidate imines (5 H -1,2,3-oxathiazole 2,2-dioxides) have received increasing attention as useful precursors for the synthesis of many valuable heterocycles. This review highlights recent developments in this area.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6RP00244G
Abstract: Students can now digitally construct their own representations of scientific concepts using a variety of modes including writing, diagrams, 2-D and 3-D models, images or speech, all of which communicate meaning. In this study, final-year chemistry students studying a pharmacology subject created a “blended media” digital product as an assignment to summarize an independently prepared technical literature review on a current research topic in pharmacology for a non-expert audience. A blended media is a simplified way for students to combine a variety of modes to complement a narration to explain a concept to others. In this study, the students learned how to create a blended media during a one-hour workshop, and used the technique to create the representation as an assessment task. The research question that guided the study was, “What are the students’ perceptions of making a digital product such as blended media and how did these shape their multimodal awareness?” We draw from theoretical perspectives in multimodalities, representations and meaning making. Data included interviews at three points of the semester, the literature review and the digital media product. We present three case studies with volunteering students, who demonstrated a strong awareness of effective communications techniques as they attended to the audience. Making a blended media is a creative way for chemistry students to summarize complex scientific information and as a task may help to focus their multimodal awareness and developing communications skills.
Publisher: Elsevier BV
Date: 09-2012
DOI: 10.1016/J.VETPAR.2012.03.022
Abstract: A pen experiment was conducted to investigate the interaction of early-weaning and nutrient supply on the periparturient relaxation of immunity to the gastrointestinal nematode (GIN) Trichostrongylus colubriformis in Merino ewes. Mixed-age pregnant and non-pregnant (dry) ewes were infected with 8,000 T. colubriformis L(3)/week, and fed either a high or low quality diet. Following parturition, lambs were either removed from their mothers at 2 days of age or allowed to continue suckling. Systemic immunity began to wane during late pregnancy with circulating eosinophils and plasma total antibody (Ab) levels declining from day -37 (relative to the midpoint of lambing) and day -24, respectively. Pregnant ewes fed the low quality diet exhibited an increasing faecal worm egg count (WEC) from day -24 and had higher intestinal worm burdens on day 13, whereas ewes fed the high quality diet had a delayed transient rise in WEC of lower magnitude. Dry and early-weaned ewes remained highly resistant to T. colubriformis at all times. In the post-lambing/lactation period, ewes fed the high quality diet had higher levels of local total Ab and numbers of goblet cells (GC) in the small intestine on days 13 and 41. Lactating/suckled ewes had a lower anti-parasite local immune response as indicated by reduced titres of total Ab, IgG(1), IgM and IgA and lower numbers of mucosal mast cells (MMC), globule leukocytes (GL) and GC in small intestinal tissue compared to their dry and early-weaned counterparts. Early-weaning resulted in rapid recovery of blood eosinophils and total Ab. On day 13 post-lambing, titres of total Ab, IgG(1), IgM, IgA and IgE, and numbers of MMC and GL were greater than those measured in dry and suckled ewes. When fed the high quality diet, ewes had a higher dry matter (DM) intake, maternal weight, fat score, greater fat depth and eye muscle depth, birthed heavier lambs that had higher growth rates, and produced more milk. The physiological status of pregnancy resulted in a higher DM intake but lower measures of fat depth and eye muscle depth, and suckling led to an increase in DM intake but a reduction in body weight and fat score through mobilisation of fat and muscle reserves. Despite the marked effect of diet quality on production traits, some inconsistencies were observed between body composition and apparent parasite resistance, measured by WEC and worm counts, suggesting that the nutritional influence was not necessarily always mediated through changes in body composition. Although reproductive status affected blood leptin levels, diet had no effect within suckled ewes and therefore it was concluded that leptin has no causative role in maintaining the periparturient relaxation of immunity to T. colubriformis.
Publisher: Wiley
Date: 25-07-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CC06241F
Abstract: Cyclopropenylmethyl sulfonamides with tethered heteroaromatics can undergo ergent gold-catalysed cyclisation reactions based on the nature of the aromatic tether.
Publisher: Wiley
Date: 23-04-2015
Publisher: SAGE Publications
Date: 09-06-2020
Abstract: Heavy infestations of the blood-sucking gastrointestinal nematodes, Haemonchus contortus can cause severe anaemia in sheep and leakage of blood into the faeces, leading to morbidity and mortality. Early and accurate diagnosis of infections is critical for timely treatment of sheep, minimizing production and sheep welfare impacts. In pursuit of a quick and easy measure of H. contortus infections, we investigated the use of portable visible near infrared spectrometers for detecting the presence of haemoglobin in sheep faeces as an indicator of H. contortus infection. Calibration models built within the 400–600 nm region by partial least square regression resulted in acceptable prediction accuracies (r 2 p 0.70 and root mean squared error of prediction .64 µg Hb mg −1 faeces) for haemoglobin quantification using two spectrometers. The prediction results from support vector machine regression further improved the prediction of haemoglobin in moist sheep faeces (r 2 p 0.87 and root mean squared error of prediction .00 µg haemoglobin mg −1 faeces). Based on a threshold for anthelmintic treatment of 3 µg Hb mg −1 faeces, both the partial least square and support vector machine models showed high sensitivity (89%) and high specificity ( %). The specificity of the prediction model for detecting haemoglobin in sheep faeces may be improved by adding more variations in faecal composition into the calibration model. Our success in detecting haemoglobin in sheep faeces, following minimal s le preparation, suggests that with further development, vis–near infrared spectroscopy can provide a sensitive and convenient method for on-farm diagnosis of H. contortus infections.
Publisher: Wiley
Date: 23-06-2009
Publisher: American Chemical Society (ACS)
Date: 13-09-2013
DOI: 10.1021/JO401544E
Abstract: DFT calculations have been carried out in order to rationalize and predict the ring-opening regioselectivity of substituted cyclopropenes in the presence of gold(I) catalysts. It has been shown that the regioselectivity of these ring-opening processes is driven by the relative π-donor ability of the substituents on the cyclopropene double bond (C1 and C2). A stronger π-donor substituent at C2 favors Au(I)-induced polarization of the double bond toward C1, resulting in preferential breaking of the C1-C3 bond. An excellent correlation between ΔE(++) and the difference in the C1-C2 p(π) orbital population was observed for a broad range of substituents, providing a useful predictive model for gold-induced cyclopropene ring-opening. Furthermore, it was found that the stability of the resulting gold-stabilized allyl-cation intermediates do not follow the same trend as the ring-opening reaction energies. Generally, the more facile ring-opening process led to the less thermodynamically stable intermediate, which lacked stabilization of the carbocation by a π-donor in the α-position.
Publisher: American Chemical Society (ACS)
Date: 04-12-2017
Abstract: A trans-diastereoselective Pd-catalyzed dearomative [3 + 2] cycloaddition between vinylcyclopropane dicarboxylates and 3-nitroindoles has been developed. The reaction provides densely functionalized cyclopenta[b]indolines with versatile vinyl and nitro-groups. The addition of a halide additive was found to be critical for the diastereoselectivity of the reaction, which is proposed to be a result of a rapid π-σ-π interconversion between the intermediates allowing for Curtin-Hammett control. A switch in diastereoselectivity to afford products with the vinyl and nitro groups cis to each other is observed with a 4-substituted 3-nitroindole.
Publisher: Georg Thieme Verlag KG
Date: 08-2006
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8CY02482K
Abstract: PR 3 AuOTf-Catalyzed hydrofunctionalisation of nonactivated alkenes using acetic acid and phenol was found to take place via a binuclear mechanism.
Publisher: Wiley
Date: 03-02-2019
DOI: 10.1111/JNC.14655
Publisher: Wiley
Date: 28-07-2011
Publisher: American Chemical Society (ACS)
Date: 19-06-2019
Publisher: University of Toronto Press Inc. (UTPress)
Date: 09-2017
DOI: 10.3138/IJCS.56.2017-0004
Abstract: In this article, I examine how a select group of English-Canadian social science, humanities, and law academics made significant contributions to Canadian foreign policy and diplomacy during the Second World War. Leaving the confines of their universities to work in wartime Ottawa through a formal secondment process, an influential and yet heretofore unrecognized group of seconded academics became key administrators and diplomats working on behalf of the Canadian state in the sphere of external affairs. Aiding a federal civil service short on administrative talent, seconded academics staffed crucially important posts in the Department of External Affairs, Department of Finance, Wartime Prices and Trade Board, and Wartime Information Board. Although permanent officials handled most issues regarded as first rank, the academics analyzed in this article did the heavy lifting in the committees and preparatory deskwork, making strong contributions to those issues of second rank, including the formulation and refinement of Canadian foreign policy. Academics also became both official and unofficial diplomats representing the nation in erse international fora. During the Second World War, the federal civil service did not have enough personnel to handle all the representational duties, and academics stepped in to fill an important void. Through their work in the international sphere, academics actively sought to forge a new Canadian identity and facilitate a process whereby Canada became less overtly British and more sovereign and independent.
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/AN18378
Abstract: Context Parasite control is an essential part of a broader equine health-management strategy and is often completely administered by the horse owner, with little or no supporting evidence on which to base decisions. Practical and sound advice relies on knowledge of the resident parasite species, the anthelmintic resistance status of important species, and the strategies currently being utilised by owners and managers of horses. Much of this farm-level information is lacking in the Australian literature. Aims The present study aimed to gather both farm- and horse-level prevalence data for four important equine helminth species and to gather information on the current worm-management practices conducted on Australian horse farms. Methods We conducted a coprological survey of cyathostomins, Strongylus vulgaris, Parascaris spp. and equine tapeworm on 102 horse properties, using a combination of classical and molecular parasitological methods, including a tapeworm polymerase chain reaction developed as part of the study. A questionnaire canvasing horse owners on internal parasite-control practices was also distributed. Key results Cyathostomin were present on all farms surveyed and S. vulgaris, despite being considered rare, was present on 7.8% (95% CI: 3.9–15.0) of farms. The prevalence of Parascaris spp. and equine tapeworm was 33.3% (95% CI: 19.6–50.6) and 3.9% (95% CI: 1.5–10.1) respectively. Questionnaire responses showed that the majority (85.0%) of horse owners administer anthelmintics at regular intervals of 12 weeks or less, and only 2.6% utilise faecal egg counts to inform treatment decisions. Conclusions Prevalence data confirmed the endemic nature of cyathostomin and P. equorum infections, as well as low levels of tapeworm and S. vulgaris infections on Australian horse farms. Worm-management practices were reminiscent of traditional interval-style treatment regimens that rely heavily on macrocyclic lactone anthelmintics. Implications These results suggest a need for more strategic approaches to internal-parasite control in horses to slow the development of anthelmintic resistance. Such programs need to consider the risk of re-establishment of the pathogenic S. vulgaris in significant numbers.
Publisher: Wiley
Date: 02-2022
Abstract: Thermally induced cycloisomerization reactions of 1,6‐allenynes gives α‐methylene‐γ‐lactams via intramolecular Alder‐ene reactions. The mechanism is supported by computational and deuterium labelling studies. This thermal, non‐radical method enables the discovery of a hitherto unknown route that proceeds via a ergent mechanism distinct from the previous [2+2] cycloisomerization manifold.
Publisher: American Chemical Society (ACS)
Date: 10-04-2023
Publisher: Elsevier BV
Date: 2023
Publisher: American Chemical Society (ACS)
Date: 28-09-2010
DOI: 10.1021/OL101862U
Abstract: Cyclopropenylmethyl acetates have been shown to undergo rapid and stereoselective gold catalyzed rearrangement to Z-acetoxydienes in high yield. DFT calculations have shown that while several reaction pathways can be envisaged only a single, ring-opening one operates.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0SC04390G
Abstract: Room temperature Rh-catalysed tetradehydro-Diels–Alder reaction via an unusual Rh-stabilised allene.
Publisher: American Chemical Society (ACS)
Date: 10-09-2005
DOI: 10.1021/JO051385C
Abstract: Propargylic boranes generated by lithiation of optically active N-propargyloxazolidinones undergo reaction with a range of aldehydes to produce gamma,gamma-disubstituted allenamides with good diastereoselectivity.
Publisher: Royal Society of Chemistry (RSC)
Date: 1973
DOI: 10.1039/P29730000223
Publisher: Wiley
Date: 12-12-2006
Publisher: Wiley
Date: 28-02-2006
Publisher: American Chemical Society (ACS)
Date: 04-03-2022
Abstract: Density functional theory (DFT) is used in this work to predict the mechanism for constructing congested quaternary-quaternary carbon(sp
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B504731E
Abstract: A novel route to the synthesis of 3-(tolylsulfonyl)-4,5-cis-disubstituted gamma-lactams using a diastereoselective palladium-catalysed intramolecular allylation of amino acid-derived allylic carbonates has been developed.
Publisher: Elsevier
Date: 2015
Publisher: American Chemical Society (ACS)
Date: 29-09-2006
DOI: 10.1021/JO061340R
Abstract: Chiral gamma-substituted allenamides have been shown to undergo efficient gold-catalyzed and N-iodosuccinimide-mediated cyclization to highly functionalized dihydrofurans. These reactions proceed rapidly and without loss of stereochemistry.
Publisher: Georg Thieme Verlag KG
Date: 20-03-2020
Abstract: A diastereoselective palladium-catalyzed dearomative formal (4+2) cycloaddition between vinyl benzoxazinanones and 3-nitroindoles has been developed. This reaction provides a concise route to tetrahydro-5H-indolo[2,3-b]quinolines in excellent yield (up to 94%) and diastereoselectivity (up to :2), with versatile functional handles including vinyl, nitro, and free NH groups.
Publisher: American Chemical Society (ACS)
Date: 07-02-2012
DOI: 10.1021/OM2008106
Publisher: Wiley
Date: 25-09-2023
Publisher: American Chemical Society (ACS)
Date: 17-06-2022
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/CH18197
Abstract: Herein we report the formation of pyrrolines and tetrahydropyridines from the cyclisation reactions of β-amino allenes by both AuI and AgI catalysts in yields ranging from 5 to 70 %. AuI catalysts favour a 5-endo-dig cyclisation before rapid rearrangement to the 5-exo-dig product, while AgI favours a 6-endo-trig cyclisation. We also report the first known Ag2O catalysed cyclisation reaction of an allene which occurred in good yield (61 %).
Publisher: Springer Science and Business Media LLC
Date: 29-04-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3SC01510F
Abstract: Formation of valuable spiroheterocycles with multiple contiguous stereogenic centres from palladium-catalysed enantioselective (3 + 2) cycloaddition reactions of sulfamidate-derived azadienes and vinylcyclopropanes.
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B815971H
Abstract: The highly regioselective, stereospecific ring-opening of trisubstituted N-tosylaziridines possessing vinyl and hydroxymethyl groups by sulfone- and sulfide-stablised carbanions is reported.
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/CH18196
Abstract: A study of the reactivity of a non-stabilised azomethine ylide, derived from N-(methoxymethyl)-N-(trimethylsilylmethyl)benzylamine, with nitro-substituted isatoic anhydrides was undertaken. N-Methyl-4-nitroisatoic anhydride underwent a 1,3-dipolar cycloaddition reaction exclusively at the isatoic anhydride C1-carbonyl group, followed by decarboxylative rearrangement to yield a benzo-1,3-diazepin-5-one derivative. In contrast, N-methyl-5-nitroisatoic anhydride underwent competing cycloaddition processes to the isatoic anhydride C1-carbonyl group and to the nitro-substituted aromatic ring. The dearomative addition reaction resulted in the formation of novel tetracyclic products.
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 06-2018
End Date: 06-2024
Amount: $381,855.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2018
End Date: 12-2023
Amount: $357,072.00
Funder: Australian Research Council
View Funded Activity