Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 61 - 90 of 1143

Full-Text Articles in Physical Sciences and Mathematics

Architecture And Conservation Of The Bacterial Dna Replication Machinery, An Underexploited Drug Target, Andrew Robinson, Rebecca J. Causer, Nicholas E. Dixon Jan 2012

Architecture And Conservation Of The Bacterial Dna Replication Machinery, An Underexploited Drug Target, Andrew Robinson, Rebecca J. Causer, Nicholas E. Dixon

Faculty of Science - Papers (Archive)

"New antibiotics with novel modes of action are required to combat the growing threat posed by multi-drug resistant bacteria. Over the last decade, genome sequencing and other high-throughput techniques have provided tremendous insight into the molecular processes underlying cellular functions in a wide range of bacterial species. We can now use these data to assess the degree of conservation of certain aspects of bacterial physiology, to help choose the best cellular targets for development of new broad-spectrum antibacterials. DNA replication is a conserved and essential process, and the large number of proteins that interact to replicate DNA in bacteria are …


The Extracellular Chaperone Clusterin Sequesters Oligomeric Forms Of The Amyloid-Beta 1-40 Peptide, Priyanka Narayan, Angel Orte, Richard W. Clarke, Benedetta Bolognesi, Sharon Hook, Kristina A. Ganzinger, Sarah Meehan, Mark R. Wilson, Christopher M. Dobson, David Klenerman Jan 2012

The Extracellular Chaperone Clusterin Sequesters Oligomeric Forms Of The Amyloid-Beta 1-40 Peptide, Priyanka Narayan, Angel Orte, Richard W. Clarke, Benedetta Bolognesi, Sharon Hook, Kristina A. Ganzinger, Sarah Meehan, Mark R. Wilson, Christopher M. Dobson, David Klenerman

Faculty of Science - Papers (Archive)

In recent genome-wide association studies, the extracellular chaperone protein, clusterin, has been identified as a newly-discovered risk factor in Alzheimer's disease. We have examined the interactions between human clusterin and the Alzheimer's disease-associated amyloid-β 1-40 peptide (Aβ 1-40), which is prone to aggregate into an ensemble of oligomeric intermediates implicated in both the proliferation of amyloid fibrils and in neuronal toxicity. Using highly sensitive single-molecule fluorescence methods, we have found that Aβ 1-40 forms a heterogeneous distribution of small oligomers (from dimers to 50-mers), all of which interact with clusterin to form long-lived, stable complexes. Consequently, clusterin is able …


Investigating Arsenic Speciation And Mobilization In Sediments With Dgt And Det: A Mesocosm Evaluation Of Oxic-Anoxic Transitions, William W. Bennett, Peter R. Teasdale, Jarad G. Panther, David T. Welsh, Huijun Zhao, Dianne F. Jolley Jan 2012

Investigating Arsenic Speciation And Mobilization In Sediments With Dgt And Det: A Mesocosm Evaluation Of Oxic-Anoxic Transitions, William W. Bennett, Peter R. Teasdale, Jarad G. Panther, David T. Welsh, Huijun Zhao, Dianne F. Jolley

Faculty of Science - Papers (Archive)

Mobilization of arsenic from freshwater and estuarine sediments during the transition from oxic to anoxic conditions was investigated using recently developed diffusive sampling techniques. Arsenic speciation and Fe(II) concentrations were measured at high resolution (1−3 mm) with in situ diffusive gradients in thin films (DGT) and diffusive equilibration in thin films (DET) techniques. Water column anoxia induced Fe(II) and As(III) fluxes from the sediment. A correlation between water column Fe(II) and As(III) concentrations was observed in both freshwater (rs = 0.896, p < 0.001) and estuarine (rs = 0.557, p < 0.001) mesocosms. Porewater sampling by DGT and DET techniques confirmed that arsenic mobilization was associated with the reductive dissolution of Fe(III) (hydr)oxides in the suboxic zone of the sediment; a relationship that was visible because of the ability to measure the coincident profiles of these species using combined DGT and DET samplers. The selective measurement of As(III) and total inorganic arsenic by separate DGT samplers indicated that As(III) was the primary species mobilized from the solid phase to the porewater. This measurement approach effectively ruled out substantial As(V) mobilization from the freshwater and estuarine sediments in this experiment. This study demonstrates the capabilities of the DGT and DET techniques for investigating arsenic speciation and mobilization over a range of sediment conditions.


Roles Of Extracellular Chaperones In Amyloidosis, Amy R. Wyatt, Justin J. Yerbury, Rebecca A. Dabbs, Mark R. Wilson Jan 2012

Roles Of Extracellular Chaperones In Amyloidosis, Amy R. Wyatt, Justin J. Yerbury, Rebecca A. Dabbs, Mark R. Wilson

Faculty of Science - Papers (Archive)

Extracellular protein misfolding and aggregation underlie many of the most serious amyloidoses including Alzheimer's disease, spongiform encephalopathies and type II diabetes. Despite this, protein homeostasis (proteostasis) research has largely focussed on characterising systems that function to monitor protein conformation and concentration within cells. We are now starting to identify elements of corresponding systems, including an expanding family of secreted chaperones, which exist in the extracellular space. Like their intracellular counterparts, extracellular chaperones are likely to play a central role in systems that maintain proteostasis; however, the precise details of how they participate are only just emerging. It is proposed that …


Land Management Practices Associated With House Loss In Wildfires, Philip Gibbons, Linda Van Bommel, A Malcolm Gill, Geoffrey J. Cary, Don A. Driscoll, Ross A. Bradstock, Emma Knight, Max A. Moritz, Scott L. Stephens, David B. Lindenmayer Jan 2012

Land Management Practices Associated With House Loss In Wildfires, Philip Gibbons, Linda Van Bommel, A Malcolm Gill, Geoffrey J. Cary, Don A. Driscoll, Ross A. Bradstock, Emma Knight, Max A. Moritz, Scott L. Stephens, David B. Lindenmayer

Faculty of Science - Papers (Archive)

Losses to life and property from unplanned fires (wildfires) are forecast to increase because of population growth in periurban areas and climate change. In response, there have been moves to increase fuel reduction—clearing, prescribed burning, biomass removal and grazing—to afford greater protection to peri-urban communities in fire-prone regions. But how effective are these measures? Severe wildfires in southern Australia in 2009 presented a rare opportunity to address this question empirically. We predicted that modifying several fuels could theoretically reduce house loss by 76%–97%, which would translate to considerably fewer wildfire-related deaths. However, maximum levels of fuel reduction are unlikely to …


Lime Muds And Their Genesis Off-Northwestern India During The Late Quaternary, V P. Rao, A Anil Kumar, S W A Naqvi, Allan R. Chivas, B Sekar, Pratima M. Kessarkar Jan 2012

Lime Muds And Their Genesis Off-Northwestern India During The Late Quaternary, V P. Rao, A Anil Kumar, S W A Naqvi, Allan R. Chivas, B Sekar, Pratima M. Kessarkar

Faculty of Science - Papers (Archive)

Two sediment types were found in five gravity cores collected from water depths between 56 m and 121 m along the northwestern continental margin of India: lime muds were abundant in the lower section while siliciclastic sediments dominated the upper section. Lime mud-dominated sediments in shelf cores contained 60%–75% carbonate, 0.3%–0.6% Sr and terrigenous minerals, whereas those at the shelf break were found to have >90% carbonate, 0.6%–0.8% Sr and traces of terrigenous minerals. Aragonite needles showing blunt edges, jointed needles and needles wrapped in smooth aragonite cement were found to be common. Stable (O and C) isotopes of lime …


Biface Distributions And The Movius Line: A Southeast Asian Perspective, Adam Brumm, Mark W. Moore Jan 2012

Biface Distributions And The Movius Line: A Southeast Asian Perspective, Adam Brumm, Mark W. Moore

Faculty of Science - Papers (Archive)

The ‘Movius Line’ is the putative technological demarcation line mapping the easternmost geographical distribution of Acheulean bifacial tools. It is traditionally argued by proponents of the Movius Line that ‘true’ Acheulean bifaces, especially handaxes, are only found in abundance in Africa and western Eurasia, whereas in eastern Asia, in front of the ‘line’, these implements are rare or absent altogether. Here we argue, however, that the Movius Line relies on classifying undated surface bifaces as Acheulean on typological grounds alone, a long-standing and widely accepted practice in Africa and western Eurasia, but one that is not seen as legitimate in …


Inhomogeneities In Yba 2cu 3o 7 Thin Films With Reduced Thickness, O V. Shcherbakova, A V. Pan, S K. Gorman, S A. Fedoseev, I A. Golovchanskiy, S. X. Dou Jan 2012

Inhomogeneities In Yba 2cu 3o 7 Thin Films With Reduced Thickness, O V. Shcherbakova, A V. Pan, S K. Gorman, S A. Fedoseev, I A. Golovchanskiy, S. X. Dou

Faculty of Science - Papers (Archive)

Morphology and physical properties of mono- (YBa2Cu3O7) and multilayered (YBa2Cu3O7/SmBa2Cu3O7/ YBa2Cu3O7) superconducting thin films with thickness ranging from 90 nm to 28 nm have been investigated. For both types of samples, the superconducting properties degraded with reduction of film thickness. Structural and electromagnetic properties were visualized through scanning electron microscopy and magneto-optical imaging, respectively, and revealed high level of inhomogeneity for thinner (<58 >nm) samples. However, samples with thickness above 58 nm showed enhanced homogeneity, which …


Larval Tolerance To Salinity In Three Species Of Australian Anuran: An Indication Of Saline Specialisation In Litoria Aurea, Brian D. Kearney, Phillip G. Byrne, Richard D. Reina Jan 2012

Larval Tolerance To Salinity In Three Species Of Australian Anuran: An Indication Of Saline Specialisation In Litoria Aurea, Brian D. Kearney, Phillip G. Byrne, Richard D. Reina

Faculty of Science - Papers (Archive)

Recent anthropogenic influences on freshwater habitats are forcing anuran populations to rapidly adapt to high magnitude changes in environmental conditions or face local extinction. We examined the effects of ecologically relevant elevated salinity levels on larval growth, metamorphosis and survival of three species of Australian anuran; the spotted marsh frog (Limnodynastes tasmaniensis), the painted burrowing frog (Neobatrachus sudelli) and the green and golden bell frog (Litoria aurea), in order to better understand the responses of these animals to environmental change. Elevated salinity (16% seawater) negatively impacted on the survival of L. tasmaniensis (35% survival) …


Commentary: Career Progress Relative To Opportunity: How Many Papers Is A Baby 'Worth'?, Natascha Klocker, Danielle Drozdzewski Jan 2012

Commentary: Career Progress Relative To Opportunity: How Many Papers Is A Baby 'Worth'?, Natascha Klocker, Danielle Drozdzewski

Faculty of Science - Papers (Archive)

How many papers is a baby ‘worth’? We were prompted to ask this provocative question by recent experiences, working on appointment committees and writing research grants in Australia, where provisions to quantify research track-records ‘relative to opportunity’ call for applicants to explain how fl uctuations in their publication outputs have been impacted by ‘career interruptions’ such as childbearing. In this age of the increasingly neoliberal university—where every activity, output, and impact is audited (Castree, 2000; 2006)—our commentary seeks to question how decision makers account (or not) for the career impacts of having children.


Luminescence Dating Of Chinese Loess Beyond 130 Ka Using The Non-Fading Signal From K-Feldspar, Bo Li, Shenghua Li Jan 2012

Luminescence Dating Of Chinese Loess Beyond 130 Ka Using The Non-Fading Signal From K-Feldspar, Bo Li, Shenghua Li

Faculty of Science - Papers (Archive)

A multi-elevated-temperature post-IR IRSL (MET-pIRIR) protocol, which utilizes the IRSL signals measured by progressively increasing the stimulation temperature from 50 to 300 ℃ in a step of 50 ℃, was applied to date the potassium-rich feldspar (K-feldspar) extracts from loess samples at the Luochuan section of the Chinese Loess Plateau. It was observed that the MET-pIRIR ages obtained at elevatedtemperatures (250 and 300 ℃) are consistent with independent chronological control for the samples from the first loess layer (L1) to the third paleosol layer (S3), which correspond to the marine isotope stages (MIS) 2e9. Our results indicate that the MET-pIRIR …


Comparing The Information Content Of Coral Reef Geomorphological And Biological Habitat Maps, Amirantes Archipelago (Seychelles), Western Indian Ocean, S Hamylton, S Andrefouet, T Spencer Jan 2012

Comparing The Information Content Of Coral Reef Geomorphological And Biological Habitat Maps, Amirantes Archipelago (Seychelles), Western Indian Ocean, S Hamylton, S Andrefouet, T Spencer

Faculty of Science - Papers (Archive)

Increasing the use of geomorphological map products in marine spatial planning has the potential to greatly enhance return on mapping investment as they are commonly two orders of magnitude cheaper to produce than biologically-focussed maps of benthic communities and shallow substrates. The efficacy of geomorphological maps derived from remotely sensed imagery as surrogates for habitat diversity is explored by comparing two map sets of the platform reefs and atolls of the Amirantes Archipelago (Seychelles), Western Indian Ocean. One mapping campaign utilised Compact Airborne Spectrographic Imagery (19 wavebands, 1 m spatial resolution) to classify 11 islands and associated reefs into 25 …


Climate Change, Fuel And Fire Behaviour In A Eucalypt Forest, Stuart Matthews, Andrew L. Sullivan, Penny Watson, Richard J. Williams Jan 2012

Climate Change, Fuel And Fire Behaviour In A Eucalypt Forest, Stuart Matthews, Andrew L. Sullivan, Penny Watson, Richard J. Williams

Faculty of Science - Papers (Archive)

A suite of models was used to examine the links between climate, fuels and fire behaviour in dry eucalypt forests in south-eastern Australia. Predictions from a downscaled climate model were used to drive models of fuel amount, the moisture content of fuels and two models of forest fire behaviour at a location in western Sydney in New South Wales, Australia. We found that a warming and drying climate produced lower fine fuel amounts, but greater availability of this fuel to burn due to lower moisture contents. Changing fuel load had only a small effect on fuel moisture. A warmer, drier …


Decentring 1788: Beyond Biotic Nativeness, Lesley M. Head Jan 2012

Decentring 1788: Beyond Biotic Nativeness, Lesley M. Head

Faculty of Science - Papers (Archive)

The usefulness of the concept of biotic nativeness has been challenged in both the social and natural sciences, for different reasons. This paper explores the particular construction of nativeness in Australia in relation to plants, showing that the definition builds on and inscribes more deeply the boundary between humans and the rest of nature seen in the wider literature. In this context two further boundaries are etched: between some humans and others, and before and after European colonisation. Such a use of nativeness as an axiom of environmental management is argued to be problematic, foreclosing a number of future options …


Long-Range Correlations In Fourier Transform Infrared, Satellite, And Modeled Co In The Southern Hemisphere, Olaf Morgenstern, Guang Zeng, Stephen W. Wood, John Robinson, Dan Smale, Clare Paton-Walsh, Nicholas B. Jones, David W. T Griffith Jan 2012

Long-Range Correlations In Fourier Transform Infrared, Satellite, And Modeled Co In The Southern Hemisphere, Olaf Morgenstern, Guang Zeng, Stephen W. Wood, John Robinson, Dan Smale, Clare Paton-Walsh, Nicholas B. Jones, David W. T Griffith

Faculty of Science - Papers (Archive)

We use Fourier transfonn infrared ground-based measurements and satellite and model data to assess long-range correlations in tropospheric carbon monoxide. We fmd that CO columns measured in New Zealand correlate well with those measured in Antarctica, if a transport-related lag is taken into account. The model suggests that this long-range correlation is part of a mode of anomalous CO comprising almost the whole southern extratropics, which is linked to biomass burning in the southern continents. No such mode is modeled for the Northern Hemisphere. The area of long-range correlations maximizes for the southern subtropical Pacific, which is identified as an …


Molecular Characterization Of Commensal Escherichia Coli Adapted To Different Compartments Of The Porcine Gastrointestinal Tract, Sam Abraham, David M. Gordon, James Chin, Huub J. M Brouwers, Peter Njuguna, Mitchell D. Groves, Ren Zhang, Toni A. Chapman Jan 2012

Molecular Characterization Of Commensal Escherichia Coli Adapted To Different Compartments Of The Porcine Gastrointestinal Tract, Sam Abraham, David M. Gordon, James Chin, Huub J. M Brouwers, Peter Njuguna, Mitchell D. Groves, Ren Zhang, Toni A. Chapman

Faculty of Science - Papers (Archive)

The role of Escherichia coli as a pathogen has been the focus of considerable study, while much less is known about it as a commensal and how it adapts to and colonizes different environmental niches within the mammalian gut. In this study, we characterize Escherichia coli organisms (n=146) isolated from different regions of the intestinal tracts of eight pigs (dueodenum, ileum, colon, and feces). The isolates were typed using the method of random amplified polymorphic DNA (RAPD) and screened for the presence of bacteriocin genes and plasmid replicon types. Molecular analysis of variance using the RAPD data showed that E. …


Molecular Mechanisms Of K+ Selectivity In Na/K Pump, Haibo Yu, Ian Ratheal, Pablo Artigas, Benoit Roux Jan 2012

Molecular Mechanisms Of K+ Selectivity In Na/K Pump, Haibo Yu, Ian Ratheal, Pablo Artigas, Benoit Roux

Faculty of Science - Papers (Archive)

The sodium–potassium (Na/K) pump plays an essential role in maintaining cell volume and secondary active transport of other solutes by establishing the Na+ and K+ concentration gradients across the plasma membrane of animal cells. The recently determined crystal structures of the Na/K pump to atomic resolution provide a new impetus to investigate molecular determinants governing the binding of Na+ and K+ ions and conformational transitions during the functional cycle. The pump cycle is generally described by the alternating access mechanism, in which the pump toggles between different conformational states, where ions can bind from either the …


A Comparison Of Bushfire Fuel Hazard Assessors And Assessment Methods In Dry Sclerophyll Forest Near Sydney, Australia, Penny J. Watson, Sandra H. Penman, Ross A. Bradstock Jan 2012

A Comparison Of Bushfire Fuel Hazard Assessors And Assessment Methods In Dry Sclerophyll Forest Near Sydney, Australia, Penny J. Watson, Sandra H. Penman, Ross A. Bradstock

Faculty of Science - Papers (Archive)

Over the last decade, fire managers in Australia have embraced the concept of ‘fuel hazard’, and guides for its assessment have been produced. The reliability of these new metrics, however, remains to be determined. This study compared fuel hazard ratings generated by five assessment teams using two Australian hazard assessment methods, in two dry sclerophyll forest sites on Sydney’s urban fringe. Attributes that underpin hazard scores, such as cover and height of various fuel layers, were also assessed. We found significant differences between teams on most variables, including hazard scores. These differences were more apparent when fuel hazard assessments focussed …


Manipulating Thermal Stress On Rocky Shores To Predict Patterns Of Recruitment Of Marine Invertebrates Under A Changing Climate, Justin A. Lathlean, Todd E. Minchinton Jan 2012

Manipulating Thermal Stress On Rocky Shores To Predict Patterns Of Recruitment Of Marine Invertebrates Under A Changing Climate, Justin A. Lathlean, Todd E. Minchinton

Faculty of Science - Papers (Archive)

For rocky intertidal organisms, temperature is often considered the most influential factor governing early survival and growth. Nevertheless, our review of the literature revealed that few studies have manipulated temperatures in the field to test for effects on these critical early life history processes. Here, we present the results from a novel manipulation of substratum temperature using settlement plates of different colour (black, grey and white) and infrared measurements of temperature to test hypotheses that temperature influences the early survival and growth of recent settlers of the intertidal barnacle Tesseropora rosea. Mean surface temperatures of black and grey plates …


Living Together But Apart: Material Geographies Of Everyday Sustainability In Extended Family Households, Natascha Klocker, Chris Gibson, Erin Borger Jan 2012

Living Together But Apart: Material Geographies Of Everyday Sustainability In Extended Family Households, Natascha Klocker, Chris Gibson, Erin Borger

Faculty of Science - Papers (Archive)

In the Industrialized West, ageing populations and cultural diversity-combined with rising property prices and extensive years spent in education-have been recognized as diverse factors driving increases in extended family living. At the same time, there is growing awareness that household size is inversely related to per capita resource consumption patterns, and that urgent problems of environmental sustainability are negotiated, on a day-to-day basis (and often unconsciously), at the household level. This paper explores the sustainability implications of everyday decisions to fashion, consume, and share resources around the home, through the lens of extended family households. Through interviews with extended family …


P2x7 Receptor Activation Mediates Organic Cation Uptake Into Human Myeloid Leukaemic Kg-1 Cells, Safina Gadeock, Aleta Pupovac, Vanessa Sluyter, Mari Spildrejorde, Ronald Sluyter Jan 2012

P2x7 Receptor Activation Mediates Organic Cation Uptake Into Human Myeloid Leukaemic Kg-1 Cells, Safina Gadeock, Aleta Pupovac, Vanessa Sluyter, Mari Spildrejorde, Ronald Sluyter

Faculty of Science - Papers (Archive)

The P2X7 purinergic receptor is an ATP-gated cation channel with an emerging role in neoplasia. In this study we demonstrate that the human KG-1 cell line, a model of acute myelogenous leukaemia, expresses functional P2X7. RT-PCR and immunochemical techniques demonstrated the presence of P2X7 mRNA and protein respectively in KG-l cells, as well as in positive control multiple myeloma RPMI 8226 cells. Flow cytometric measurements demonstrated that ATP induced ethidium(+) uptake into KG-l cells suspended in sucrose medium (EC(50) of ∼3 μM), but not into cells in NaCl medium. In contrast, ATP induced ethidium(+) uptake into RPMI 8226 cells suspended …


Using Rigorous Selection Criteria To Investigate Marine Range Shifts, Rachel Przeslawski, Inke Falkner, Michael B. Ashcroft, Pat Hutchings Jan 2012

Using Rigorous Selection Criteria To Investigate Marine Range Shifts, Rachel Przeslawski, Inke Falkner, Michael B. Ashcroft, Pat Hutchings

Faculty of Science - Papers (Archive)

We reassess whether range shifts in marine organisms are occurring in a direction predicted by causation due to climate using two different methods: a global meta-analysis and a regional analysis of museum records focussing on marine molluscs. Globally we used rigorous selection criteria to investigate studies describing range shifts in marine organisms, including exclusion of single-species studies and those that inferred range shifts through shifting abundance. For each species meeting these criteria (311 species from 13 studies), the distance in kilometres moved per year was calculated, and life history characteristics such as mobility, habitat, dispersal potential and trophic level were …


Driving, Cities And Changing Climates, Gordon R. Waitt, Theresa Harada Jan 2012

Driving, Cities And Changing Climates, Gordon R. Waitt, Theresa Harada

Faculty of Science - Papers (Archive)

The relevance of cars in relation to changing climates seems indisputable: scientific evidence points out the significant contribution of cars globally in causing greenhouse gas emissions. Despite higher levels of general public understanding and concern about climate change, this has not generally resulted in decreased car use. This paper outlines how a spatial perspective drawing on a cultural economy approach may provide insights into the paradox of the environmental ‘value action gap’ by focusing on suburban belongings, passions and anticipations derived from driving. Drawing on insights from Burraneer Bay, an affluent Sydney suburb, the paper illustrates how habituated and embodied …


Slip Rate Of The Aksay Segment Of Altyn Tagh Fault Revealed By Osl Dating Of River Terraces, Yiwei Chen, Sheng-Hua Li, Bo Li Jan 2012

Slip Rate Of The Aksay Segment Of Altyn Tagh Fault Revealed By Osl Dating Of River Terraces, Yiwei Chen, Sheng-Hua Li, Bo Li

Faculty of Science - Papers (Archive)

The slip rate of Altyn Tagh Fault (ATF) was studied near the Aksay segment (39°24.572´N, 94°16.012´E), China, based on dating the terraces of a river passing through the ATF. Two river terrace risers were offset by the ATF and the fault displacements were recorded. Average slip rate of the Aksay segment of the ATF was estimated using the offset of terrace risers divided by the corresponding ages. The ages of the terraces were determined by optical dating of the loess deposited on the river terrace. Our results demonstrated that: (1) The optically stimulated luminescence (OSL) ages of loess can be …


A Reply To The Comments By Thomsen Et Al. On "Luminescence Dating Of K-Feldspar From Sediments: A Protocol Without Anomalous Fading Correction", Bo Li, Shenghua Li Jan 2012

A Reply To The Comments By Thomsen Et Al. On "Luminescence Dating Of K-Feldspar From Sediments: A Protocol Without Anomalous Fading Correction", Bo Li, Shenghua Li

Faculty of Science - Papers (Archive)

We are pleased that Thomsen et al. (2012) has tested our newly proposed multi-elevated-temperature post-IR IRSL (MET-pIRIR) procedure (Li and Li, 2011) using their own samples, which provides an independent test on the validity of this procedure. In their study, Thomsen et al. (2012) found that the METpIRIR procedure gave consistent results with the two-step post-IR IRSL (TS-pIRIR) procedure originally proposed by [Thomsen et al., 2008] and [Buylaert et al., 2009] and Thiel et al. (2010), indicating the validity of both methods for their samples investigated. Based on this observation, they argued that the MET-pIRIR procedure has no advantage over …


The Synthesis, Structures And Reactions Of Zinc And Cobalt Metal-Organic Frameworks Incorporating An Alkyne-Based Dicarboxylate Linker, Andrew D. Burrows, L C. Fisher, David M. Hodgson, Mary F. Mahon, Naomi Cessford, Tina Duren, Christopher Richardson, S P. Rigby Jan 2012

The Synthesis, Structures And Reactions Of Zinc And Cobalt Metal-Organic Frameworks Incorporating An Alkyne-Based Dicarboxylate Linker, Andrew D. Burrows, L C. Fisher, David M. Hodgson, Mary F. Mahon, Naomi Cessford, Tina Duren, Christopher Richardson, S P. Rigby

Faculty of Science - Papers (Archive)

The reaction of zinc(II) nitrate and 4,4′-ethynylenedibenzoic acid (H2edb) in DMF at 80 °C gave the metal–organic framework material [Zn4O(edb)3(H2O)2]·6DMF 1 in which edb ligands connect Zn4O centres into a doubly-interpenetrated cubic network with a similar topology to observed with other linear dicarboxylates in the IRMOF series. Analysis of the nitrogen isotherm revealed the material to have a BET surface area of 1088 m2 g−1, which is approximately one-third of the value calculated from GCMC simulations, suggesting incomplete activation or pore blocking in the activated …


Riverine Source Of Arctic Ocean Mercury Inferred From Atmospheric Observations, Jenny A. Fisher, Daniel J. Jacob, Anne L. Soerensen, Helen M. Amos, Alexandra Steffen, Elsie M. Sunderland Jan 2012

Riverine Source Of Arctic Ocean Mercury Inferred From Atmospheric Observations, Jenny A. Fisher, Daniel J. Jacob, Anne L. Soerensen, Helen M. Amos, Alexandra Steffen, Elsie M. Sunderland

Faculty of Science - Papers (Archive)

Methylmercury is a potent neurotoxin that accumulates in aquatic food webs. Human activities, including industry and mining, have increased inorganic mercury inputs to terrestrial and aquatic ecosystems. Methylation of this mercury generates methylmercury, and is thus a public health concern. Marine methylmercury is a particular concern in the Arctic, where indigenous peoples rely heavily on marine-based diets. In the summer, atmospheric inorganic mercury concentrations peak in the Arctic, whereas they reach a minimum in the northern mid-latitudes. Here, we use a global three-dimensional ocean–atmosphere model to examine the cause of this Arctic summertime maximum. According to our simulations, circumpolar rivers …


Meteorological Modes Of Variability For Fine Particulate Matter (Pm2.5) Air Quality In The United States: Implications For Pm2.5 Sensitivity To Climate Change, A. P K. Tai, L J. Mickley, D J. Jacob, E M. Leibensperger, L Zhang, J A. Fisher, H. O T. Pye Jan 2012

Meteorological Modes Of Variability For Fine Particulate Matter (Pm2.5) Air Quality In The United States: Implications For Pm2.5 Sensitivity To Climate Change, A. P K. Tai, L J. Mickley, D J. Jacob, E M. Leibensperger, L Zhang, J A. Fisher, H. O T. Pye

Faculty of Science - Papers (Archive)

We applied a multiple linear regression model to understand the relationships of PM2.5 with meteorological variables in the contiguous US and from there to infer the sensitivity of PM2.5 to climate change. We used 2004–2008 PM2.5 observations from ~1000 sites (~200 sites for PM2.5 components) and compared to results from the GEOS-Chem chemical transport model (CTM). All data were deseasonalized to focus on synoptic-scale correlations. We find strong positive correlations of PM2.5 components with temperature in most of the US, except for nitrate in the Southeast where the correlation is negative. Relative humidity (RH) is …


Radiocarbon Bomb Spike Reveals Biological Effects Of Antarctic Climate Change, Laurence J Clarke, Sharon A. Robinson, Quan Hua, David J. Ayre, David Fink Jan 2012

Radiocarbon Bomb Spike Reveals Biological Effects Of Antarctic Climate Change, Laurence J Clarke, Sharon A. Robinson, Quan Hua, David J. Ayre, David Fink

Faculty of Science - Papers (Archive)

The Antarctic has experienced major changes in temperature, wind speed and stratospheric ozone levels during thelast 50 years. However, until recently continental Antarctica appeared to be little impacted by climate warming, thusbiological changes were predicted to be relatively slow. Detecting the biological effects of Antarctic climate changehas been hindered by the paucity of long-term data sets, particularly for organisms that have been exposed to thesechanges throughout their lives. We show that radiocarbon signals are preserved along shoots of the dominant Antarcticmoss flora and use these to determine accurate growth rates over a period of several decades, allowing us toexplore the …


Gelapin, A Degradable Genipin Cross-Linked Gelatin Hydrogel, Damian Kirchmajer, C Watson, Marie Ranson, Marc In Het Panhuis Jan 2012

Gelapin, A Degradable Genipin Cross-Linked Gelatin Hydrogel, Damian Kirchmajer, C Watson, Marie Ranson, Marc In Het Panhuis

Faculty of Science - Papers (Archive)

The synthesis of genipin cross-linked gelatin (Gelapin) hydrogel materials is presented. Gelapin hydrogels were comprehensively characterised through chemical, mechanical and physical analysis techniques. It was found that the hydrogels could be cross-linked to up to 90% using a genipin concentration of 24.4% (w/ w). The hydrogels reach a stable swollen state and cease leaching of residual starting materials after 72 h in phosphate buffered saline solution at 37 uC. The proteolytic degradation of Gelapin by collagenase is tuneable through manipulation of the material composition with the rate of degradation ranging from 60 mg per day up to 500 mg per …