B. Barry

Non‐diadromous recruitment in coastal populations of common bully (Gobiomorphus cotidianus)

Abstract Otolith microchemistry of common bullies (Gobiomorphus cotidianus) collected from the lower reaches of the Mataura, Clutha, and Taieri/Waipori River systems of New Zealand was examined using particle induced X‐ray emission (PIXE). High strontium:calcium (Sr:Ca) ratios in otolith cores relative to otolith edges suggested either diadromous or estuarine‐reared common bullies are present in all three systems, including fish collected from Clydevale (50 km inland) on the Clutha River. However, constant or slightly variable Sr:Ca ratios from otolith core to edge, suggesting a non‐diadromous life history, were also observed in fish from the lower Mataura and Taieri/Waipori systems, even where access to the sea was continuously available. The results suggest that diadromy in common bully may be facultative, and that a proportion of the common bully population may be non‐diadromous in river systems where suitable larval/juvenile rearing habitat is present.

Atmospheric deposition of 7Be and 10Be in New Zealand rain (1996-98)

Abstract Beryllium isotope concentrations were determined in monthly rainfall collections at three sites across New Zealand (36 to 45° S), from October 1996 to November 1998. At the northern sites of Leigh (near Auckland) and Gracefield (near Wellington), 7 Be and 10 Be concentrations are relatively constant at 1.2 to 1.4 × 10 7 atoms kg −1 rain and 2.1 to 2.6 × 10 7 atoms kg −1 rain, respectively. These concentrations correspond to annual flux rates of ∼15 and ∼27 × 10 9 atoms m −2 y −1 , respectively. At the southern site of Dunedin, concentrations are similar to those at the northern sites, but flux rates are significantly lower at ∼ 9 and ∼19 × 10 9 atoms m −2 y −1 , respectively, because of lower average rainfall east of the Southern Alps mountain range. These results are broadly similar to those reported by Brown et al. (1989) and Knies et al. (1994) for rain from midlatitude sites in the USA sampled from 1986 to 1994. Mean 7 Be/ 10 Be ratios for New Zealand (0.47 to 0.61) are, however, significantly lower than for the USA (0.69 to 0.78), due in part to the addition of 10 Be from re-suspended dust. Subtraction of the dust component increases the New Zealand 7 Be/ 10 Be ratios to 0.70 (Leigh), 0.65 (Gracefield) and 0.50 (Dunedin). The adjusted results provide evidence for transfer of older stratospheric air to the troposphere in late-spring-summer, an effect which is strongest in the north. The overall reduction of 7 Be/ 10 Be from north to south implies an increase in residence time from ∼ 80 to ∼100 d for Be isotopes in the atmosphere above New Zealand.

Air particulate matter pollution in Ulaanbaatar, Mongolia: determination of composition, source contributions and source locations

Ulaanbaatar, the capital city of Mongolia is subject to high air particulate matter pollution episodes during winter and during dust storm events in spring and autumn that have severe implications for the health of the exposed population. This paper presents the results of fine (PM2.5) and coarse (PM10–2.5) particulate matter monitoring in Ulaanbaatar from 2004 to 2008 and receptor modelling to determine the sources contributing to particulate matter pollution. Ion Beam Analysis was used to determine elemental concentrations in the two size fractions and black carbon was measured with a light reflectance device. Mass contributions to ambient particle concentrations from emission sources were estimated by positive matrix factorisation and air mass back–trajectory analysis was used to assess probable source locations. The results show that crustal matter sources are the primary contributors to the coarse particle fraction. Combustion sources (coal combustion, biomass burning, and motor vehicles) dominate the fine fraction of particulate matter in the Ulaanbaatar airshed, primarily from local emission sources but forest fires to the north can be a significant contributor to biomass burning concentrations at times. Analysis of seasonal differences showed that coal combustion processes were largely responsible for fine particle air pollution episodes during winter. Temporal trends show an increase in the coal combustion contributions over the monitoring period. We suggest that this is linked to the increase in the Ulaanbaatar population and a consequent increase in the use of coal for power generation and domestic heating purposes.

Diabetic cardiomyopathy is associated with defective myocellular copper regulation and both defects are rectified by divalent copper chelation

BackgroundHeart disease is the leading cause of death in diabetic patients, and defective copper metabolism may play important roles in the pathogenesis of diabetic cardiomyopathy (DCM). The present study sought to determine how myocardial copper status and key copper-proteins might become impaired by diabetes, and how they respond to treatment with the Cu (II)-selective chelator triethylenetetramine (TETA) in DCM.MethodsExperiments were performed in Wistar rats with streptozotocin (STZ)-induced diabetes with or without TETA treatment. Cardiac function was analyzed in isolated-perfused working hearts, and myocardial total copper content measured by particle-induced x-ray emission spectroscopy (PIXE) coupled with Rutherford backscattering spectrometry (RBS). Quantitative expression (mRNA and protein) and/or activity of key proteins that mediate LV-tissue-copper binding and transport, were analyzed by combined RT-qPCR, western blotting, immunofluorescence microscopy, and enzyme activity assays. Statistical analysis was performed using Student’s t-tests or ANOVA and p-values of < 0.05 have been considered significant.ResultsLeft-ventricular (LV) copper levels and function were severely depressed in rats following 16-weeks’ diabetes, but both were unexpectedly normalized 8-weeks after treatment with TETA was instituted. Localized myocardial copper deficiency was accompanied by decreased expression and increased polymerization of the copper-responsive transition-metal-binding metallothionein proteins (MT1/MT2), consistent with impaired anti-oxidant defences and elevated susceptibility to pro-oxidant stress. Levels of the high-affinity copper transporter-1 (CTR1) were depressed in diabetes, consistent with impaired membrane copper uptake, and were not modified by TETA which, contrastingly, renormalized myocardial copper and increased levels and cell-membrane localization of the low-affinity copper transporter-2 (CTR2). Diabetes also lowered indexes of intracellular (IC) copper delivery via the copper chaperone for superoxide dismutase (CCS) to its target cuproenzyme, superoxide dismutase-1 (SOD1): this pathway was rectified by TETA treatment, which normalized SOD1 activity with consequent bolstering of anti-oxidant defenses. Furthermore, diabetes depressed levels of additional intracellular copper-transporting proteins, including antioxidant-protein-1 (ATOX1) and copper-transporting-ATPase-2 (ATP7B), whereas TETA elevated copper-transporting-ATPase-1 (ATP7A).ConclusionsMyocardial copper deficiency and defective cellular copper transport/trafficking are revealed as key molecular defects underlying LV impairment in diabetes, and TETA-mediated restoration of copper regulation provides a potential new class of therapeutic molecules for DCM.

Protection of the heart by treatment with a divalent-copper-selective chelator reveals a novel mechanism underlying cardiomyopathy in diabetic rats

BackgroundIntracellular calcium (Ca2+) coordinates the cardiac contraction cycle and is dysregulated in diabetic cardiomyopathy. Treatment with triethylenetetramine (TETA), a divalent-copper-selective chelator, improves cardiac structure and function in patients and rats with diabetic cardiomyopathy, but the molecular basis of this action is uncertain. Here, we used TETA to probe potential linkages between left-ventricular (LV) copper and Ca2+ homeostasis, and cardiac function and structure in diabetic cardiomyopathy.MethodsWe treated streptozotocin-diabetic rats with a TETA-dosage known to ameliorate LV hypertrophy in patients with diabetic cardiomyopathy. Drug treatment was begun either one (preventative protocol) or eight (restorative protocol) weeks after diabetes induction and continued thereafter for seven or eight weeks, respectively. Total copper content of the LV wall was determined, and simultaneous measurements of intracellular calcium concentrations and isometric contraction were made in LV trabeculae isolated from control, diabetic and TETA-treated diabetic rats.ResultsTotal myocardial copper levels became deficient in untreated diabetes but were normalized by TETA-treatment. Cardiac contractility was markedly depressed by diabetes but TETA prevented this effect. Neither diabetes nor TETA exerted significant effects on peak or resting [Ca2+]i. However, diabetic rats showed extensive cardiac remodelling and decreased myofibrillar calcium sensitivity, consistent with observed increases in phosphorylation of troponin I, whereas these changes were all prevented by TETA.ConclusionsDiabetes causes cardiomyopathy through a copper-mediated mechanism that incorporates myocardial copper deficiency, whereas TETA treatment prevents this response and maintains the integrity of cardiac structure and myofibrillar calcium sensitivity. Altered calcium homeostasis may not be the primary defect in diabetic cardiomyopathy. Rather, a newly-described copper-mediated mechanism may cause this disease.

Validation of cosmogenic nuclide production rate scaling factors through direct measurement

Abstract 7Be produced in water targets by nuclear interactions of cosmic rays has been measured to determine cosmogenic nuclide production rates as a function of altitude (sea level to 2 km) and geomagnetic latitude (20–79°S). Relative intensities of low energy cosmic ray neutrons have at the same time been measured using neutron monitors based on IGY/NM-64 designed to efficiently thermalise ca. 2–30 MeV neutrons. The research is on-going and we present here preliminary data from the past two years. Water target and neutron flux results are in general agreement, and are consistent with the altitude-dependent scaling factors of Lal [Earth Planet. Sci. Lett. 104 (1991) 4241]. Significant differences between the sea level, latitude-dependent neutron flux data and Lals predictions are possibly related to the response function of the detector.

Eutrophication indicators in the Hutt River Estuary, New Zealand

Abstract The Hutt River estuary near Wellington New Zealand has a luxuriant intertidal band of green macroalgae growing throughout the year. Investigations of water chemistry suggested that the upstream freshwater river was likely P-limited and passed on watershed nitrogen nutrients to the estuary. P fertilisation of the estuary from marine waters led to crossing N and P nutrient loadings that support the observed macroalgal proliferation. Chemical analyses of nutrients, macroalgae, and barnacle and mussel consumers were used to understand further the mix of factors controlling eutrophication and food webs in this urban estuary. δ15N and δ13C were respective helpful indicators of watershed N inputs and C cycling between benthic and pelagic parts of the food web.

PIXE ANALYSIS OF SEDIMENTS AFFECTED BY THE DECEMBER 2004 INDIAN OCEAN TSUNAMI

The aim of this project is to apply particle induced X-ray emission analysis for the assessment of elemental variations in sediment samples collected after the 2004 Boxing Day tsunami event in Thailand. Samples were collected in June 2007 at two near-shore locations (C-1 and C-2) along the east coast of Phuket Island. The C-1 and C-2 sites received moderate and low impacts from the tsunami, respectively. For each location, sediment cores of 0.75m were collected. Sediment samples extracted from the cores were dried to constant weight at 60°C. All samples were prepared as a fine homogeneous powder by grinding and passing through a 125 µm sieve. Pellets were pressed from these samples. It was found by comparison with a suite of standard soils and sediments that the Si, Al and K contents of these moderate and low-impact Tsunami effected sediment samples are low by a factor of about two. Chlorine was detected at up to about 20000 ppm in both series with suggestions of a decrease at greater depth in the cores. Iron was detected in all samples, and was found at higher concentration in the samples from the C-1 site with a trend to higher concentration at greater depth. By contrast the two shallow C-2 samples showed a higher concentration than the deeper samples. Titanium was detected at the 1000–2000 ppm level in both series with no discernable depth trends.

RECENT DEVELOPMENTS IN THE AIR PARTICULATE RESEARCH CAPABILITY AT THE NEW ZEALAND ION BEAM ANALYSIS FACILITY

The New Zealand capability in Ion Beam Analysis of air particulate samples has been upgraded in recent years. The main equipment change has been the introduction of the ability to analyse samples taken using the Streaker (PIXE International Corporation) sampling system. This is an automated sampler which allows for great flexibility in monitoring programmes by collecting particulates for up to about 70 sampling periods which can range in collection times from seconds to many hours. The IBA analysis for hydrogen on standard filters and for PIXE multi-elemental analysis of the Streaker filters has also been studied with a view to optimising analytical methods.

FLUORINE AND CALCIUM PROFILING BY PIGE/PIXE FOR EXPOSURE AGE DATING IN ARCHAEOLOGY

Fossil fragments of bone and teeth that are exposed to a humid environment take up fluorine from the surrounding soil and accumulate it in their mineral phase. In cortical parts of long bone diaphysis a fluorine concentration profile can be observed, which carries information on the exposure duration of the buried object in its shape. The distribution of fluorine in a sample however is strongly influenced by environmentally induced processes of bone diagenesis, i.e. alteration in the structure and composition of bone mineral and degradation of the organic components that may make the time information indistinct. PIGE (Proton Induced Gamma-ray Emission) is a precise and fast analytical technique to determine the quantitative fluorine content and its distribution in cross sections of bone and tooth specimen non-destructively. The simultaneous detection of Ca by PIXE (Proton Induced X-ray Emission) provides additional information on the sample topography. Cracks, alteration haloes and the porosity, which is typical for human bone samples, are parameters which have direct influence on the fluorine uptake and transport during burial. This contribution outlines the combined approach of using PIGE and PIXE measurement to understand some aspects of the complex environmental impact that impedes exposure age dating by fluorine diffusion profiling.