Heavy metal bioavailability and bioaccessibility in soil

This chapter considers the use of a variety of approaches to assess either the bioavailability or the bioaccessibility of metals in soil. The bioavailability of metals from soils is considered with respect to a series of single-extraction methods, including the use of ethylenediaminetetraacetic acid (EDTA), acetic acid, diethylenetriaminepentaacetic acid (DTPA), ammonium nitrate, calcium chloride and sodium nitrate. Then, a procedure for the recovery of metals using a three-stage sequential extraction protocol is described. Two alternate approaches for assessing the environmental health risk to humans by undertaking in vitro gastrointestinal extraction (also known as the physiologically based extraction test, PBET) are considered. Finally, two acid digestion protocols that allow the pseudo-total metal content of samples to be assessed are provided. In all cases details of how the different approaches can be performed are provided, including the specific reagents required (and their preparation), details of the different extraction and acid digestion protocols to be followed and suitable analytical details to allow the measurement of metals by inductively coupled plasma mass spectrometry (ICP-MS) with/without a collision/reaction cell. A detailed Notes section provides experimental details to guide the reader through some of the practical aspects of the procedures. Finally, some experimental results are provided as evidence of the suitability of the approaches described including single-extraction data, using EDTA and acetic acid, for metals in CRM BCR 700. In addition, in vitro gastrointestinal extraction data are provided for metals in CRM SRM 1570A (spinach leaves). The influence of time on the intestinal fluid phase on the recovery of metals in CRM SRM 1570A (spinach leaves) and CRM INCT-TL-1 (tea leaves) is investigated, as well as the repeatability in terms of recovery of metals from soil over a 3-week period by in vitro gastrointestinal extraction

An investigation in to the role of fatty acid binding protein-7, insulin like growth factor binding protein-2 and phosphatase and tensin homolog in triple negative breast cancer; in vitro and in vivo

IntroductionTriple negative breast cancers are defined by their lack of expression of HER, oestrogen receptors and progesterone receptors. They account for around 10-24% of cases. To define a cancer by the biomarkers it does not express is unsatisfactory. Triple negative breast cancer has been linked to aspects of metabolism and metabolic disorders such as diabetes. There are several biomarkers that are of interest and overlap in both their roles in breast cancer and in aspects of metabolism. Fatty acid binding protein 7 (FABP7) is one of 9 FABPs that is involved in the transport, solubilisation and regulation of metabolism of various fatty acids. Expression profiling and immunohistochemistry (IHC) studies have identified FABP7 to be over-expressed in a subtype of breast cancer that can be considered almost synonymous with triple negative breast cancer; basal-like breast cancer, so called because it expresses cytokeratins that are characteristic of basal epithelial cells. The role of FABP7 in breast cancer is not fully understood and studies have given conflicting results in regards to the relation to prognosis. Evidence suggests that FABP7 can be regulated by methylation acetylation and exposure to fatty acids. Insulin like growth factor binding protein-2 (IGFBP-2) is a member of the IGF-axis that is responsible for altering cell growth and metabolism. IGFBP-2 has been found to be over-expressed in many cancers including those of the prostate and breast. Phosphotensin homolog (PTEN) is a tumour suppressor gene that is responsible for dephosphorylating PIP3 to inhibit the Akt pathway and thus inhibit cell growth and promote apoptosis. IGFBP-2 has IGF independent actions; it can down-regulate PTEN through binding of an integrin receptor and therefore have mitogenic and anti-apoptotic effects. AimsTo study the expression of the metabolic biomarkers FABP7, IGFBP-2 and PTEN in clinical cases of Malaysian TN breast cancer. To use appropriate cell lines in order to more fully understand whether epigenetic mechanisms and FAs regulate FABP7 expression. To over-express FABP7 in a breast cancer cell lines and to further understand the role of FABP7 in breast cancer.MethodsIHC was used to assess FABP7, PTEN and IGFBP-2 expression in a cohort of triple negative breast cancer cases. FAs, a demethylation agent-AZA and a histone deacetylase inhibitor-TSA were used to investigate what regulated FABP7 in cell lines. Over-expression experiments were used to understand the effect of FABP7 in breast cancer cell lines.ResultsFABP7 expression in patient samples was associated with lower grade, basal-like phenotype, FAS expression and although not significant, improved patient survival. Treatment of BT-20 and MDA-MB-231 cell lines with AZA and TSA resulted in increases in FABP7 mRNA expression. Fatty acid treatment led to changes in FABP7 mRNA expression. Combinations of AZA and fatty acids gave large increases in FABP7 mRNA expression. Over-expression of FABP7 in BT-20 cells resulted in increased cell viability and although not significant changes in expression of survivin, caspase 9 and their splice variants. IGFBP-2 expression was associated with poor patient survival though this was not significant. PTEN loss was a frequent event in the cohort of triple negative breast cancer cases; 48.3% of cases had PTEN loss. PTEN loss was associated with poor patient survival though this was not significant. PTEN loss was associated with expression of IGFBP-2.Discussion & ConclusionsFABP7 is likely to play a role in patient survival as demonstrated in the patient samples. FABP7 over-expressing BT-20 cells tended to have increased survivin FL and ΔEX3 expression. Both increased mitochondrial activity and survivin expression have been found to be associated with improved prognosis in breast cancer and this may explain some mechanisms by which FABP7 results in better prognosis in the TN breast cancer cases in this study. Since FABP7 mRNA expression was not increased to fold changes comparable to oestrogen receptor re-expression after AZA and TSA treatment, it is unlikely that the FABP7 gene is methylated or regulated by acetylation. It is possible that there are genes upstream of FABP7 such as transcription factors that are regulated my methylation and acetylation and therefore impact on FABP7 expression after treatment with AZA and TSA. This is the first study that demonstrates the significant relationship between IGFBP-2 expression and PTEN loss in patient samples. PTEN loss is a frequent event in TN breast cancer. IGFBP-2 and PTEN loss may be useful markers of prognosis in TN breast cancer

Nuclear Structure Calculations with Coupled Cluster Methods from Quantum Chemistry

We present several coupled-cluster calculations of ground and excited states of 4He and 16O employing methods from quantum chemistry. A comparison of coupled cluster results with the results of exact diagonalization of the hamiltonian in the same model space and other truncated shell-model calculations shows that the quantum chemistry inspired coupled cluster approximations provide an excellent description of ground and excited states of nuclei, with much less computational effort than traditional large-scale shell-model approaches. Unless truncations are made, for nuclei like 16O, full-fledged shell-model calculations with four or more major shells are not possible. However, these and even larger systems can be studied with the coupled cluster methods due to the polynomial rather than factorial scaling inherent in standard shell-model studies. This makes the coupled cluster approaches, developed in quantum chemistry, viable methods for describing weakly bound systems of interest for future nuclear facilities.Comment: 10 pages, Elsevier latex style, Invited contribution to INPC04 proceedings, to appear in Nuclear Physics

Can perturbative QCD predict a substantial part of diffractive LHC/SSC physics?

We examine a model of hadronic diffractive scattering which interpolates between perturbative QCD and non-perturbative fits. We restrict the perturbative QCD resummation to the large transverse momentum region, and use a simple Regge-pole parametrization in the infrared region. This picture allows us to account for existing data, and to estimate the size of the perturbative contribution to future diffractive measurements. At LHC and SSC energies, we find that a cut-off BFKL equation can lead to a measurable perturbative component in traditionally soft processes. In particular, we show that the total pp cross section could become as large as 228 mb (160 mb) and the rho parameter as large as 0.23 (0.24) at the SSC (LHC).Comment: 9 pages, McGill/92-3

Rootstock influences postharvest anthracnose development in 'Hass' avocado

Rootstock studies conducted on ‘Hass’ avocado found that rootstock had a significant impact on postharvest anthracnose susceptibility. This is the first record of such an effect for avocado. The severity and incidence of anthracnose was significantly lower on ‘Hass’ grafted to ‘Velvick’ Guatemalan seedling rootstock compared with the ‘Duke 6’ Mexican seedling rootstock. Differences in anthracnose susceptibility were related to significant differences in concentrations of antifungal dienes in the leaves and mineral nutrients in the leaves and fruits from trees grafted to different rootstocks. Leaf diene concentrations were up to 1.5 times higher in ‘Hass’ trees on the ‘Velvick’ than the ‘Duke 6’ rootstock. In ungrafted nursery stock trees, diene concentrations were around 3 times higher in ‘Velvick’ than ‘Duke 6’ leaves. The ‘Velvick’/‘Hass’ combination also had a significantly lower leaf N concentration, a significantly higher fruit flesh Mn concentration, and significantly lower and higher leaf N/Ca and Ca+Mg/K ratios, respectively. A significant correlation (r = 0.82) between anthracnose severity and skin N/Ca ratio was also evident

Going online: successes and challenges in delivering group music instrument and aural learning for older adult novices during the COVID-19 pandemic

As a result of the COVID-19 pandemic, many cultural and artistic programs for older adults have been put on hold, despite the numerous physical, social, and emotional well-being benefits continued participation may bring. This article details a cross-section of participants (n = 13) in the Active Minds Music Ensemble—a longitudinal Australian-based research project that provides 12 months of group music instrument lessons to healthy older adult novices—who transitioned from face-to-face (F2F) to an online format. Research questions include the benefits and challenges for older adults as they cope with the technological demands of “going online,” perceived effects on teaching and older adults’ musical learning, as well as perceived effects on group learning benefits. Qualitative data were collected from three different perspectives: i) a frequently asked questions (FAQ) report from the research team documenting technological issues, ii) individual semi-structured interviews with the participants, and iii) a reflective report from the teacher. The findings confirm that online group music instrument lessons are viable for and valued by older adults, with appreciation of continued technical support. Teaching and learning changed as a result of the online format, primarily in the reduction of individual feedback and less interplay between participants; this was mitigated by use of various functions such as chat, whiteboards, and breakout rooms. Implications for older adult online music instrument lessons include providing continued technical support to learners and helping them maintain confidence with technology. Social opportunities for informal “side-chatter” may also help them to empathize with and encourage each other during music learning activities

Stochastic Vehicle Routing with Recourse

We study the classic Vehicle Routing Problem in the setting of stochastic optimization with recourse. StochVRP is a two-stage optimization problem, where demand is satisfied using two routes: fixed and recourse. The fixed route is computed using only a demand distribution. Then after observing the demand instantiations, a recourse route is computed -- but costs here become more expensive by a factor lambda. We present an O(log^2 n log(n lambda))-approximation algorithm for this stochastic routing problem, under arbitrary distributions. The main idea in this result is relating StochVRP to a special case of submodular orienteering, called knapsack rank-function orienteering. We also give a better approximation ratio for knapsack rank-function orienteering than what follows from prior work. Finally, we provide a Unique Games Conjecture based omega(1) hardness of approximation for StochVRP, even on star-like metrics on which our algorithm achieves a logarithmic approximation.Comment: 20 Pages, 1 figure Revision corrects the statement and proof of Theorem 1.

Recruitment of a critically endangered sawfish into a riverine nursery depends on natural flow regimes

The freshwater sawfish (Pristis pristis) was recently listed as the most Evolutionarily Distinct and Globally Endangered (EDGE) animal. The Fitzroy River in the remote Kimberley region of north-western Australia represents a significant stronghold for the species, which uses the freshwater reaches of the river as a nursery. There is also mounting pressure to develop the water resources of the region for agriculture that may substantially affect life history dynamics of sawfish in this system. However, the relationship between hydrology and population dynamics of freshwater sawfish was unknown. We used standardized catch data collected over 17 years to determine how wet season volume influences recruitment of freshwater sawfish into their riverine nursery. Negligible recruitment occurred in years with few days of high flood levels (above 98th percentile of cease-to-flow stage height), and relatively high recruitment occurred in years with 14 or more days of high flood levels. This relationship is indicative of a distinct boom-or-bust cycle, whereby freshwater sawfish rely almost entirely on the few years with large wet season floods, and the brief periods of highest water levels within these years, to replenish juvenile populations in the Fitzroy River nursery. This has direct implications for sustainable water resource management for the Fitzroy River basin in order to preserve one of the last known intact nursery habitats for this globally threatened species

Optical Detection of a Single Nuclear Spin

We propose a method to optically detect the spin state of a 31-P nucleus embedded in a 28-Si matrix. The nuclear-electron hyperfine splitting of the 31-P neutral-donor ground state can be resolved via a direct frequency discrimination measurement of the 31-P bound exciton photoluminescence using single photon detectors. The measurement time is expected to be shorter than the lifetime of the nuclear spin at 4 K and 10 T.Comment: 4 pages, 3 figure

Lorentz breaking Effective Field Theory and observational tests

Analogue models of gravity have provided an experimentally realizable test field for our ideas on quantum field theory in curved spacetimes but they have also inspired the investigation of possible departures from exact Lorentz invariance at microscopic scales. In this role they have joined, and sometime anticipated, several quantum gravity models characterized by Lorentz breaking phenomenology. A crucial difference between these speculations and other ones associated to quantum gravity scenarios, is the possibility to carry out observational and experimental tests which have nowadays led to a broad range of constraints on departures from Lorentz invariance. We shall review here the effective field theory approach to Lorentz breaking in the matter sector, present the constraints provided by the available observations and finally discuss the implications of the persisting uncertainty on the composition of the ultra high energy cosmic rays for the constraints on the higher order, analogue gravity inspired, Lorentz violations.Comment: 47 pages, 4 figures. Lecture Notes for the IX SIGRAV School on "Analogue Gravity", Como (Italy), May 2011. V.3. Typo corrected, references adde