PCA of Fe-oxides MLA data as an advanced tool in provenance discrimination and indicator mineral exploration : case study from bedrock and till from the Kiggavik U deposits area (Nunavut, Canada)

Magnetite and hematite grains from the 0.25–0.5 mm and 0.5–2.0 mm ferromagnetic fractions of ten till samples collected up-ice, overlying and down-ice of the Kiggavik U deposits (Nunavut, Canada), as well as eight bedrock samples from Kiggavik igneous and metasedimentary basement and overlying sedimentary rocks were characterized for their grain size and mineral association using optical microscopy, scanning electron microscopy (SEM) and mineral liberation analysis (MLA). Principal component analysis (PCA) was used to evaluate the MLA data for Fe-oxide mineral association and grain size distribution. PCA shows that mineralogical and granulometric differences in Fe-oxides from Kiggavik igneous rocks distinguish them from that of Kiggavik metasedimentary and sedimentary rocks. In addition, The PCA results indicate that the composition and abundance of minerals associated/intergrown with Fe-oxides are not only different in various till samples, but also in different size fractions of the same sample. Higher proportions of hornblende, quartz, gahnite, grunerite, apatite, chromite and sulfides are intergrown with Fe-oxides in the 0.5–2.0 mm till fraction, as compared to the 0.25–0.5 mm fraction in which Fe-oxides are mostly associated with pyroxene, titanite, rutile, feldspars, calcite and zircon. The mineral associations and grain sizes of proximal bedrocks are reflected in smaller size fractions of Kiggavik till, whereas detrital grains in the 0.5–2.0 mm fraction of Kiggavik till may have originated from distal sources. PCA also shows that Fe-oxides from the Kiggavik bedrock and till can be discriminated from those of volcanogenic massive sulfide (VMS) deposits because of smaller grain sizes and higher abundances of sulfides, gahnite, axinite, corundum, hypersthene and pyroxene intergrown with VMS Fe-oxides. This study emphasizes the importance of selecting suitable representative grain size fractions of till, or other sediments, when using indicator minerals for exploration. The results of PCA of Fe-oxides MLA data are consistent with the results of using Fe-oxides geochemical data in provenance discrimination of Kiggavik till

Plasmid-Cured Chlamydia caviae Activates TLR2-Dependent Signaling and Retains Virulence in the Guinea Pig Model of Genital Tract Infection

Loss of the conserved “cryptic” plasmid from C. trachomatis and C. muridarum is pleiotropic, resulting in reduced innate inflammatory activation via TLR2, glycogen accumulation and infectivity. The more genetically distant C. caviae GPIC is a natural pathogen of guinea pigs and induces upper genital tract pathology when inoculated intravaginally, modeling human disease. To examine the contribution of pCpGP1 to C. caviae pathogenesis, a cured derivative of GPIC, strain CC13, was derived and evaluated in vitro and in vivo. Transcriptional profiling of CC13 revealed only partial conservation of previously identified plasmid-responsive chromosomal loci (PRCL) in C. caviae. However, 2-deoxyglucose (2DG) treatment of GPIC and CC13 resulted in reduced transcription of all identified PRCL, including glgA, indicating the presence of a plasmid-independent glucose response in this species. In contrast to plasmid-cured C. muridarum and C. trachomatis, plasmid-cured C. caviae strain CC13 signaled via TLR2 in vitro and elicited cytokine production in vivo similar to wild-type C. caviae. Furthermore, inflammatory pathology induced by infection of guinea pigs with CC13 was similar to that induced by GPIC, although we observed more rapid resolution of CC13 infection in estrogen-treated guinea pigs. These data indicate that either the plasmid is not involved in expression or regulation of virulence in C. caviae or that redundant effectors prevent these phenotypic changes from being observed in C. caviae plasmid-cured strains

Geochemistry of magnetite and hematite from unmineralized bedrock and local till at the Kiggavik uranium deposit : implications for sediment provenance

The petrography and mineral chemistry of magnetite and hematite from igneous, metasedimentary, and sedimentary bedrock in the area of the Kiggavik unconformity-related uranium deposit, and from till covering the deposit were investigated using optical microscopy, scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The R-package rob-Compositions method was used to treat censored values in the EPMA and LA-ICP-MS geochemical data, and the results were transformed using a centered log-ratio transformation prior to data analysis using partial least squares-discriminant analysis (PLS-DA). The Kiggavik rock samples are from a wide range of lithologies including granite, leucogranite, syenite, metagreywacke, quartzite, and quartz arenite. The integration of petrography and mineral chemistry identifies four origins for iron oxides in the Kiggavik bedrocks: magmatic, hydrothermal, diagenetic, and weathering. The igneous bedrocks mainly contain magmatic magnetite replaced by mostly hydrothermal and rarely by weathering related hematite. Higher concentrations of trace elements such as Mg, Al, Ti, and Zr in hydrothermal hematite from leucogranite, granite and Martell syenite relative to parent magnetite suggest that hematite crystallized from high-temperatures hydrothermal fluids. By contrast, relative trace elements depletion in hematite replacing V-Cr-rich magnetite from Schultz Lake Intrusive Complex syenite may indicate hematite precipitation from low-temperature oxidizing fluids. The high U content (450 ppm averagely), rounded shape, and altered edges of hematite grains from metagreywacke indicate that the iron oxide is detrital, originally precipitated from U-rich hydrothermal fluids. Quartzite also contains hydrothermal hematite. Distinct chemical compositions of hydrothermal hematite from Kiggavik metasedimentary and igneous basement demonstrate different compositions and temperatures of parental hydrothermal fluids, as well as different compositions of replaced minerals/host rocks. Magnetite rarely occurs in the Kiggavik sedimentary bedrocks as it has been partly or entirely replaced by hematite. The Thelon Formation quartz arenite contains detrital hematite mainly sourced from weathering of the Kiggavik igneous basement, and also diagenetic hematite that formed in situ replacing detrital magnetite, ilmenite, sulfides and/or Fe-bearing silicates. PLS-DA distinguishes different compositions of magnetite and hematite characterizing the various Kiggavik rock samples. The PLS-DA latent variable subspaces defined by the bedrock samples were used to classify the sources of iron oxides in Kiggavik till. The results show that magnetite and hematite from the till are mainly derived from local rocks, with a small proportion from unknown host rocks. PLS-DA identifies Si, Ca, Pb, Zr, Al, Ge, Nb, Ga, Mn, Mg, Ti, Co, Y U, V, Ni, and Cr as main discriminator elements. Their variable concentrations in iron oxides can be used to separate different Kiggavik rocks. PLS-DA also demonstrates that lower concentrations of Si, Ca, Al, Mn, Mg, Ti, Zn, Co and Ni discriminate Kiggavik iron oxides from magnetite from porphyry, iron oxide copper gold ore deposits (IOCG), Iron Oxide-Apatite (IOA), and Bayan Obo Fe-Nb-REE deposit types. Nickel enrichment and higher Ca values also differentiate magnetite from Ni-Cu, and from VMS deposits and VMS-related BIF, respectively, from Kiggavik iron oxides. The PLS-DA discrimination models suggest that volcanogenic massive sulfide (VMS)-related banded iron formations (BIF) are the potential source for some of the unclassified iron oxide grains in Kiggavik till. Retention of U contents by iron oxides during phase transformation or in detrital hematite indicates the ability of iron oxides to act as a long term repository of U. Overall, this study shows that magnetite and hematite are efficient minerals for provenance studies and mineral exploration in uranium rich environments, and also indicates that robust models for classification of indicator minerals origins in unconsolidated sediments can be established from PLS-DA of LA-ICP-MS data

Multiple effects of genetic background on variegated transgene expression in mice.

BLG/7 transgenic mice express an ovine beta-lactoglobulin transgene during lactation. Unusually, transgene expression levels in milk differ between siblings. This variable expression is due to variegated transgene expression in the mammary gland and is reminiscent of position-effect variegation. The BLG/7 line was created and maintained on a mixed CBA x C57BL/6 background. We have investigated the effect on transgene expression of backcrossing for 13 generations into these backgrounds. Variable transgene expression was observed in all populations examined, confirming that it is an inherent property of the transgene array at its site of integration. There were also strain-specific effects on transgene expression that appear to be independent of the inherent variegation. The transgene, compared to endogenous milk protein genes, is specifically susceptible to inbreeding depression. Outcrossing restored transgene expression levels to that of the parental population; thus suppression was not inherited. Finally, no generation-dependent decrease in mean expression levels was observed in the parental population. Thus, although the BLG/7 transgene is expressed in a variegated manner, there was no generation-associated accumulated silencing of transgene expression

A strengths-based group program on self-harm : a feasibility study

Every day in Queensland, Australia, student services within schools are responding to children who have deliberately self-injured. Although school nurses are in a prime position to effectively intervene, mitigate risk, and promote healthy self-caring behaviors, no programs that focus specifically on self-harm currently exist. This feasibility study of a program to assist young people find safer alternatives to self-harm canvassed opinions of 12 school nurses in secondary schools on the Sunshine Coast in 2009. Participants showed strong support and reported that the program was much needed; had an innovative, strengths-oriented approach; incorporated an essential training component; would likely be engaging for young people; and was in appropriate format. Perceived challenges to implementation included garnering support from the school community and educational stakeholders and recruiting young people most likely to benefit. Suggested changes included providing a youth-friendly name for the programa nd formalizing inclusion criteria to select appropriate group members

A strengths-based group program on self-harm: A feasibility study

Every day in Queensland, Australia, student services within schools are responding to children who have deliberately self-injured. Although school nurses are in a prime position to effectively intervene, mitigate risk, and promote healthy self-caring behaviors, no programs that focus specifically on self-harm currently exist. This feasibility study of a program to assist young people find safer alternatives to self-harm canvassed opinions of 12 school nurses in secondary schools on the Sunshine Coast in 2009. Participants showed strong support and reported that the program was much needed; had an innovative, strengths-oriented approach; incorporated an essential training component; would likely be engaging for young people; and was in appropriate format. Perceived challenges to implementation included garnering support from the school community and educational stakeholders and recruiting young people most likely to benefit. Suggested changes included providing a youth-friendly name for the program and formalizing inclusion criteria to select appropriate group members