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Charge-On-Spring Polarizable Water Models Revisited: From Water Clusters To Liquid Water To Ice, Haibo Yu, Wilfred Van Gunsteren Jan 2004

Charge-On-Spring Polarizable Water Models Revisited: From Water Clusters To Liquid Water To Ice, Haibo Yu, Wilfred Van Gunsteren

Faculty of Science - Papers (Archive)

The properties of two improved versions of charge-on-spring �COS� polarizable water models (COS/G2 and COS/G3) that explicitly include nonadditive polarization effects are reported. In COS models, the polarization is represented via a self-consistently induced dipole moment consisting of a pair of separated charges. A previous polarizable water model (COS/B2), upon which the improved versions are based, was developed by Yu, Hansson, and van Gunsteren �J. Chem. Phys. 118, 221 �2003��. To improve the COS/B2 model, which overestimated the dielectric permittivity, one additional virtual atomic site was used to reproduce the water monomer quadrupole moments besides the water monomer dipole moment …


Molecular Dynamics Simulations Of Peptides Containing An Unnatural Amino Acid: Dimerization, Folding, And Protein Binding, Haibo Yu, Xavier Daura, Wilfred Van Gunsteren Jan 2004

Molecular Dynamics Simulations Of Peptides Containing An Unnatural Amino Acid: Dimerization, Folding, And Protein Binding, Haibo Yu, Xavier Daura, Wilfred Van Gunsteren

Faculty of Science - Papers (Archive)

We have performed molecular dynamics (MD) simulations to study the dimerization, folding, and binding to a protein of peptides containing an unnatural amino acid. NMR studies have shown that the substitution of one residue in a tripeptide β-strand by the unnatural amino acid Hao (5-HO2CCONH-2-MeO-C6H3-CO-NHNH2) modifies the conformational flexibility of the β-strand and the hydrogen-bonding properties of its two edges: The number of hydrogen-bond donors and acceptors increases at one edge, whereas at the other, they are sterically hindered. In simulations in chloroform, the Hao-containing peptide 9 (i-PrCO-Phe-Hao-Val-NHBu) forms a β-sheet–like hydrogen-bonded dimer, in good agreement with the available experimental …


Western Pacific Coral Delta18o Records Of Anomalous Holocene Variability In El Nino-Southern Oscillation, Helen V. Mcgregor, M Gagan Jan 2004

Western Pacific Coral Delta18o Records Of Anomalous Holocene Variability In El Nino-Southern Oscillation, Helen V. Mcgregor, M Gagan

Faculty of Science - Papers (Archive)

No abstract provided.


Processes Controlling Metal Transport And Retention As Metal-Contaminated Groundwaters Efflux Through Estuarine Sediments, Stuart L. Simpson, Edward J. Maher, Dianne F. Jolley Jan 2004

Processes Controlling Metal Transport And Retention As Metal-Contaminated Groundwaters Efflux Through Estuarine Sediments, Stuart L. Simpson, Edward J. Maher, Dianne F. Jolley

Faculty of Science - Papers (Archive)

Factors affecting the transport and retention of Cd, Cr, Cu, Ni, Pb and Zn in acidic groundwaters as they pass through estuarine sediments were investigated using column experiments. Acidic groundwaters caused the rapid dissolution of iron sulfide (AVS) and other iron and manganese phases from sediments that are important for metal binding and buffering. Metal breakthrough to overlying water occurred in the order of Ni>Zn>Cd>>Cu>>Cr/Pb. Metal transport increased as the sediment permeability increased, reflecting the low resistance to flow caused by larger sand-sized particles and the decreased abundance of metal adsorption sites on these materials. Metal …


Selenium Accumulation In The Cockle Anadara Trapezia, Dianne F. Jolley, William A. Maher, Jennelle Kyd Jan 2004

Selenium Accumulation In The Cockle Anadara Trapezia, Dianne F. Jolley, William A. Maher, Jennelle Kyd

Faculty of Science - Papers (Archive)

An extensive study on Se accumulation in a population of Anadara trapezia from a marine lake is reported. The effects of organism mass, gender, reproductive cycle, and season on Se accumulation and tissue distribution were investigated. Analyses showed that gender and reproductive cycle had no significant effect on Se accumulation. A. trapezia showed a strong positive correlation between Se burden and tissue mass. Constant Se concentrations were observed within individual populations but varied spatially with sediment Se concentrations. Se concentrations in tissues decreased from gills>gonad/intestineOmantleO muscleOfoot, which remained constant over 12 months, however, significantly lower concentrations were observed in …


Photosynthesis In Silico. Overcoming The Challenges Of Photosynthesis Education Using A Multimedia Cd-Rom, A. W. Russell, G. M.A. Netherwood, Sharon A. Robinson Jan 2004

Photosynthesis In Silico. Overcoming The Challenges Of Photosynthesis Education Using A Multimedia Cd-Rom, A. W. Russell, G. M.A. Netherwood, Sharon A. Robinson

Faculty of Science - Papers (Archive)

Photosynthesis is a central topic in biology education. It remains one of the most challenging, largely because of a) its conceptual difficulty, leading to lack of interest and misconceptions among students; b) the difficulties students have in visualising the process, or relating it to things they can see, especially when the topic is presented purely as a molecular process; and c) limitations to the practical demonstration of photosynthesis because equipment is either cheap, unreliable and antiquated or prohibitively expensive. In response, we have combined expertise in photosynthesis research and education, and in graphic design, to produce an interactive, multimedia package, …


Asymmetric Synthesis Of (+)-1-Epiaustraline And Attempted Synthesis Of Australine, Minyan Tang, Stephen G. Pyne Jan 2004

Asymmetric Synthesis Of (+)-1-Epiaustraline And Attempted Synthesis Of Australine, Minyan Tang, Stephen G. Pyne

Faculty of Science - Papers (Archive)

A diastereoselective synthesis of the pyrrolizidine alkaloid, (+)-1-epiaustraline has been achieved via a diastereoselective syn-dihydroxylation of a pyrrolo[1,2-c]oxazol-3-one precursor that was readily prepared by a RCM reaction. Attempts to extend this methodology to the synthesis of australine were not successful since the final pyrrolidine ring closure to produce the desired pyrrolizidine of the target molecule was not productive.


Phytochemical Studies On Stemona Burkillii Prain: Two New Dihydrostemofoline Alkaloids, Pitchaya Mungkornasawakul, Stephen G. Pyne, Araya Jatisatienr, Wilford Lie, Alison T. Ung, Kritchaya Issakul, Auntika Sawatwanich, Damrat Supyen, Chaiwat Jatisatienr Jan 2004

Phytochemical Studies On Stemona Burkillii Prain: Two New Dihydrostemofoline Alkaloids, Pitchaya Mungkornasawakul, Stephen G. Pyne, Araya Jatisatienr, Wilford Lie, Alison T. Ung, Kritchaya Issakul, Auntika Sawatwanich, Damrat Supyen, Chaiwat Jatisatienr

Faculty of Science - Papers (Archive)

Two new dihydrostemofoline alkaloids, 11(S),12(R)-dihydrostemofoline (3) and stemoburkilline (4), along with stemofoline (1) and 2’-hydroxystemofoline (2) have been isolated from a root extract of Stemona burkillii Prain. The structure and relative configuration of (3) have been determined via spectroscopic data and from comparison with synthetic 11(S),12(S)-dihydrostemofoline (5). The configuration of the exo-cyclic alkene group in (4) is tentively assigned as (E) based upon mechanistic considerations.


Asymmetric Synthesis Of (-)-Swainsonine, Karl Lindsay, Stephen G. Pyne Jan 2004

Asymmetric Synthesis Of (-)-Swainsonine, Karl Lindsay, Stephen G. Pyne

Faculty of Science - Papers (Archive)

This paper describes a new synthesis of (-)-swainsonine via the ring-closing metathesis reaction of a substituted 3-allyl-4-vinyl-2-oxazolindinone and subsequent diastereoselective syn-dihydroxylation of the resulting pyrrolo[1,2-c]oxazol-3-one.


Phytochemical And Larvicidal Studies On Stemona Curtisii: Structure Of A New Pyriodo[1,2-A]Azepine Stemona Alkaloid, Pitchaya Mungkornasawakul, Stephen G. Pyne, Araya Jatisatienr, Damrat Supyen, Chaiwat Jatisatienr, Wilford Lie, Alison T. Ung, Brian W. Skelton, Allan H. White Jan 2004

Phytochemical And Larvicidal Studies On Stemona Curtisii: Structure Of A New Pyriodo[1,2-A]Azepine Stemona Alkaloid, Pitchaya Mungkornasawakul, Stephen G. Pyne, Araya Jatisatienr, Damrat Supyen, Chaiwat Jatisatienr, Wilford Lie, Alison T. Ung, Brian W. Skelton, Allan H. White

Faculty of Science - Papers (Archive)

A new pentacyclic Stemona alkaloid, stemocurtisinol (3), with a pyrido[1,2-a]azepine A,B-ring system, and the known pyrrolo[1,2-a]azepine alkaloid oxyprotostemonine (4) have been isolated from a root extract of S. curtisii. The structure and relative stereochemistry of stemocurtisinol was determined by spectral data interpretation and X-ray crystallography. This compound is a diastereoisomer of oxystemokerrin and has the opposite configuration at C-4 and C-19. The individual alkaloid components showed significant larvicidal activity (IC50 4−39 ppm) on mosquito larvae (Anopheles minimus HO).


Synthesis Of (+)-(1r,2s,9s,9ar)-Octahydro-1h-Pyrrolo-[1,2-A]Azepine-1,2,9-Triol: A Potential Glycosidase Inhibitor, Karl B. Lindsay, Stephen G. Pyne Jan 2004

Synthesis Of (+)-(1r,2s,9s,9ar)-Octahydro-1h-Pyrrolo-[1,2-A]Azepine-1,2,9-Triol: A Potential Glycosidase Inhibitor, Karl B. Lindsay, Stephen G. Pyne

Faculty of Science - Papers (Archive)

The title compound was prepared as a potential glycosidase inhibitor. Key steps in the synthesis are vinyl epoxide aminolysis, ring-closing metathesis, cis-dihydroxylation and then ring closure.


Asymmetric Synthesis Of Polyfunctionalized Pyrrolidines And Related Alkaloids, Stephen G. Pyne, Andrew S. Davis, Nicole Gates, Joseph Hartley, Karl Lindsay, Theeraphan Machan, Minyan Tang Jan 2004

Asymmetric Synthesis Of Polyfunctionalized Pyrrolidines And Related Alkaloids, Stephen G. Pyne, Andrew S. Davis, Nicole Gates, Joseph Hartley, Karl Lindsay, Theeraphan Machan, Minyan Tang

Faculty of Science - Papers (Archive)

This account describes our recent studies on the development of a general method of preparing polyfunctionalized pyrrolidine, indolizidine, pyrrolizidine and pyrrolo[1,2-a]azepines and their related alkaloids.


Landscape Management: Is It The Future?, R. J. Whelan Jan 2004

Landscape Management: Is It The Future?, R. J. Whelan

Faculty of Science - Papers (Archive)

As a Keynote Address at the 2004 Nature Conservation Council Conference, Bushfire in a Changing Environment - New Directions in Management, this paper argues that the landscape is a template with biodiversity assets, and human assets and bushfires overlaid. Two case studies, the Greater Glider and Eastern Bristlebird, are used to illustrate how the impact of bushfire on a species is contingent on it is distributed in the landscape, relative to the locations of its remnant habitat. Mitigation of bushfire effects, using fuel-reduction programs, is a process that also needs to be considered at a landscape scale, and has the …


The Ad 1607 Coastal Flood In The Bristol Channel And Severn Estuary: Historical Records From Devon And Cornwall (Uk), S. K. Haslett, Edward A. Bryant Jan 2004

The Ad 1607 Coastal Flood In The Bristol Channel And Severn Estuary: Historical Records From Devon And Cornwall (Uk), S. K. Haslett, Edward A. Bryant

Faculty of Science - Papers (Archive)

The 1607 coastal flood was a high magnitude event that may have been the result of either a storm surge or a tsunami wave(s). Contemporary accounts describe the impacts of the surge/wave at Appledore and Barnstaple in North Devon, and a 19'x' century comment exists for Hayle in. Cornwall. An examination restricted to these local accounts reveals that the surge altitude or tsunami run-up at Appledore, at the estuary mouth, exceeded 8.5 in OD (a surge/wave height in excess of 3.28 in, possibly lip to c. 7-8 in), and at Barnstaple, about 12 km up-estuary it reached 7.53 in OD …


Plasminogen Binding By Group A Streptococcal Isolates From A Tropical Region With Hyperendemic Streptococcal Skin Infection And A High Incidence Of Invasive Infection, F. C. Mckay, Jason D. Mcarthur, Martina L. Sanderson-Smith, S. Gardam, B. J. Currie, K. S. Sriprakash, P. K. Fagan, R. J. Towers, M. R. Batzloff, G. S. Chhatwal, Marie Ranson, Mark J. Walker Jan 2004

Plasminogen Binding By Group A Streptococcal Isolates From A Tropical Region With Hyperendemic Streptococcal Skin Infection And A High Incidence Of Invasive Infection, F. C. Mckay, Jason D. Mcarthur, Martina L. Sanderson-Smith, S. Gardam, B. J. Currie, K. S. Sriprakash, P. K. Fagan, R. J. Towers, M. R. Batzloff, G. S. Chhatwal, Marie Ranson, Mark J. Walker

Faculty of Science - Papers (Archive)

Reports of resurgence in invasive group A streptococcal (GAS) infections come mainly from affluent populations with infrequent exposure to GAS. In the tropical Northern Territory (NT) of Australia, high incidence of invasive GAS disease is secondary to endemic skin infection; serotype M1 clones are rare in invasive infection; the diversity and level of exposure to GAS strains is high and no particular strains dominate. Expression of a plasminogen-binding group A streptococcal M-like protein (PAM) has been associated with skin infection in isolates elsewhere (Bessen, D., C.M. Sotir, T.M. Readdy, and S.K. Hollingshead.1996. J. Infect. Dis. 173:896-900) and subversion of the …


An Assessment Of Five Australian Polychaetes And Bivalves For Use In Whole-Sediment Toxicity Tests: Toxicity And Accumulation Of Copper And Zinc From Water And Sediment, C K. King, M C. Dowse, S L. Simpson, D F. Jolley Jan 2004

An Assessment Of Five Australian Polychaetes And Bivalves For Use In Whole-Sediment Toxicity Tests: Toxicity And Accumulation Of Copper And Zinc From Water And Sediment, C K. King, M C. Dowse, S L. Simpson, D F. Jolley

Faculty of Science - Papers (Archive)

The suitability of two polychaete worms, Australonereis ehlersi and Nephtys australiensis, and three bivalves, Mysella anomala, Tellina deltoidalis, and Soletellina alba, were assessed for their potential use in whole-sediment toxicity tests. All species except A. ehlersi, which could not be tested because of poor survival in water-only tests, survived in salinities ranging from 18‰ to 34‰ during the 96-hour exposure period. No mortality was observed in any of the species exposed to sediment compositions ranging from 100% silt to 100% sand for 10 days, thus demonstrating the high tolerance of the five species to a wide range of sediment types. …


Diet And Metabolic Syndrome: Where Does Resistant Starch Fit In?, Linda C. Tapsell Jan 2004

Diet And Metabolic Syndrome: Where Does Resistant Starch Fit In?, Linda C. Tapsell

Faculty of Health and Behavioural Sciences - Papers (Archive)

Metabolic syndrome is a term linking the clinical profiles of some of the world’s major health problems today: obesity, heart disease and diabetes. It is predicated on dietary patterns, and particularly on the delivery of fuel. The effects may be seen first in the development of abdominal obesity and insulin resistance leading to type 2 diabetes mellitus and coronary heart disease. This review examines the role resistant starch might play in the prevention and management of these conditions. Beginning with a definition of resistant starch, a critical review of the scientific literature is presented. Current knowledge suggests that resistant starch …


Jitter And Size Effects On Vection Are Immune To Experimental Instructions And Demands, Stephen A. Palmisano, Amy Y. Chan Jan 2004

Jitter And Size Effects On Vection Are Immune To Experimental Instructions And Demands, Stephen A. Palmisano, Amy Y. Chan

Faculty of Health and Behavioural Sciences - Papers (Archive)

Both coherent perspective jitter and explicit changing-size cues have been shown to improve the vection induced by radially expanding optic flow. The current study examined whether these stimulus-based vection advantages could be modified by altering cognitions/expectations about both the likelihood of self-motion perception and the purpose of the experiment. In the main experiment, participants were randomly assigned into two groups – one where the cognitive conditions biased participants towards self-motion perception and another where the cognitive conditions biased them towards object motion perception. Contrary to earlier findings by Lepecq et al (1995), we found that identical visual displays were less …