Growth and characterization of multiferroic BiMnO3_3 thin films

We have grown epitaxial thin films of multiferroic BiMnO$_3$ using pulsed laser deposition. The films were grown on SrTiO$_3$ (001) substrates by ablating a Bi-rich target. Using x-ray diffraction we confirmed that the films were epitaxial and the stoichiometry of the films was confirmed using Auger electron spectroscopy. The films have a ferromagnetic Curie temperature ($T_C$) of 85$\pm$5 K and a saturation magnetization of 1 $\mu_B$/Mn. The electric polarization as a function of electric field ($P-E$) was measured using an interdigital capacitance geometry. The $P-E$ plot shows a clear hysteresis that confirms the multiferroic nature of the thin films.Comment: 4 pages, 4 figures, submitted to J. Appl. Phy

Biodiversity of protists and nematodes in the wild nonhuman primate gut

Documenting the natural diversity of eukaryotic organisms in the nonhuman primate (NHP) gut is important for understanding the evolution of the mammalian gut microbiome, its role in digestion, health and disease, and the consequences of anthropogenic change on primate biology and conservation. Despite the ecological significance of gut-associated eukaryotes, little is known about the factors that influence their assembly and diversity in mammals. In this study, we used an 18S rRNA gene fragment metabarcoding approach to assess the eukaryotic assemblage of 62 individuals representing 16 NHP species. We find that cercopithecoids, and especially the cercopithecines, have substantially higher alpha diversity than other NHP groups. Gut-associated protists and nematodes are widespread among NHPs, consistent with their ancient association with NHP hosts. However, we do not find a consistent signal of phylosymbiosis or host-species specificity. Rather, gut eukaryotes are only weakly structured by primate phylogeny with minimal signal from diet, in contrast to previous reports of NHP gut bacteria. The results of this study indicate that gut-associated eukaryotes offer different information than gut-associated bacteria and add to our understanding of the structure of the gut microbiome.Fil: Mann, Allison E.. University of British Columbia; CanadáFil: Mazel, Florent. University of British Columbia; CanadáFil: Lemay, Matthew A.. University of British Columbia; CanadáFil: Morien, Evan. University of British Columbia; CanadáFil: Billy, Vincent. University of British Columbia; CanadáFil: Kowalewski, Miguel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Biológica de Usos Múltiples (Sede Corrientes); ArgentinaFil: Di Fiore, Anthony. University of Texas at Austin; Estados UnidosFil: Link, Andrés. Universidad de los Andes; ColombiaFil: Goldberg, Tony L.. University of Wisconsin; Estados UnidosFil: Tecot, Stacey. University of Arizona; Estados UnidosFil: Baden, Andrea L.. City University Of New York. Hunter College; Estados UnidosFil: Gomez, Andres. University of Minnesota; Estados UnidosFil: Sauther, Michelle L.. State University of Colorado at Boulder; Estados UnidosFil: Cuozzo, Frank P.. Lajuma Research Centre; SudáfricaFil: Rice, Gillian A. O.. Dartmouth College; Estados UnidosFil: Dominy, Nathaniel J.. Dartmouth College; Estados UnidosFil: Stumpf, Rebecca. University of Illinois at Urbana; Estados UnidosFil: Lewis, Rebecca J.. University of Texas at Austin; Estados UnidosFil: Swedell, Larissa. University of Cape Town; Sudáfrica. City University of New York; Estados UnidosFil: Amato, Katherine. Northwestern University; Estados UnidosFil: Wegener Parfrey, Laura. University of British Columbia; Canad

Genome-wide survey reveals dynamic widespread tissue-specific changes in DNA methylation during development

Background: Changes in DNA methylation in the mammalian genome during development are frequent events and play major roles regulating gene expression and other developmental processes. It is necessary to identify these events so that we may understand how these changes affect normal development and how aberrant changes may impact disease. Results: In this study Methylated DNA ImmunoPrecipitation (MeDIP) was used in conjunction with a NimbleGen promoter plus CpG island (CpGi) array to identify Tissue and Developmental Stage specific Differentially Methylated DNA Regions (T-DMRs and DS-DMRs) on a genome-wide basis. Four tissues (brain, heart, liver, and testis) from C57BL/6J mice were analyzed at three developmental stages (15 day embryo, E15; new born, NB; 12 week adult, AD). Almost 5,000 adult T-DMRs and 10,000 DS-DMRs were identified. Surprisingly, almost all DS-DMRs were tissue specific (i.e. methylated in at least one tissue and unmethylated in one or more tissues). In addition our results indicate that many DS-DMRs are methylated at early development stages (E15 and NB) but are unmethylated in adult. There is a very strong bias for testis specific methylation in non-CpGi promoter regions (94%). Although the majority of T-DMRs and DS-DMRs tended to be in non-CpGi promoter regions, a relatively large number were also located in CpGi in promoter, intragenic and intergenic regions (>15% of the 15,979 CpGi on the array). Conclusions: Our data suggests the vast majority of unique sequence DNA methylation has tissue specificity, that demethylation has a prominent role in tissue differentiation, and that DNA methylation has regulatory roles in alternative promoter selection and in non-promoter regions. Overall, our studies indicate changes in DNA methylation during development are a dynamic, widespread, and tissue-specific process involving both DNA methylation and demethylation.Science, Faculty ofNon UBCReviewedFacult

Medicinal and injection therapies for mechanical neck disorders: A cochrane systematic review

Objective. To systematically review randomized trials on medicines and injections used to improve pain, function/disability, and patient satisfaction in adults with mechanical neck disorders (MND) with or without associated headache or radicular findings. Methods. We searched CENTRAL (Issue 4, 2002), and MEDLINE, EMBASE, MANTIS, CINHAL from their start to March 2003. Two authors independently selected articles, abstracted data, and assessed methodological quality using the Jadad criteria. When clinical heterogeneity was absent, we combined studies using random-effects metaanalysis models. Results. Thirty-two selected trials had an overall methodological quality of mean 3.2/5. For acute whiplash, administering intravenous methylprednisolone within 8 hours reduced pain at one week [SMD -0.90 (95% CI -1.57 to -0.24)], and sick leave but not pain at 6 months compared to placebo. For chronic MND at short-term followup, intramuscular injection of lidocaine was superior to placebo [SMD 1.36 (95% CI -1.93 to -0.80)]. In chronic MND with radicular findings, epidural methylprednisolone and lidocaine reduced neck pain [SMD -1.46 (95% CI -2.16 to -0.76)] and improved function at one-year followup compared to the intramuscular route. In subacute/chronic MND, we found conflicting evidence for oral psychotropic agents. In chronic MND with or without radicular findings or headache, there was moderate evidence from 5 high quality trials showing that botulinum toxin (Botox A) intramuscular injections were not better than saline in improving pain [SMD pooled -0.39 (95% CI -1.25 to 0.47)], disability, or global perceived effect. Conclusion. Intramuscular injection of lidocaine for chronic MND and intravenous injection of methylprednisolone for acute whiplash were effective treatments. There was limited evidence of effectiveness of epidural injection of methylprednisolone and lidocaine for chronic MND with radicular findings. Muscle relaxants and nonsteroidal antiinflammatory drugs have unclear benefits. There was moderate evidence that Botox-A intramuscular injections for chronic MND were not better than saline

Comparison of environmental DNA and SCUBA diving methods to survey keystone rockfish species on the Central Coast of British Columbia, Canada

The rocky reefs of British Columbia’s (BC) coast are a productive ecosystem, home to 38 rockfish species (Genus: Sebastes) that are culturally and economically important. Quantitatively assessing rockfish populations is vital to support conservation and stock assessment needs. Self-contained underwater breathing apparatus (SCUBA) diving surveys are a commonly used monitoring method in BC. However, this resource-intensive approach is challenging, particularly for cryptic or deeper species. Herein, we compared environmental DNA (eDNA) detection methods with SCUBA diving surveys to capture overall rockfish biodiversity. We employed two eDNA methods: 1) a targeted quantitative real-time polymerase chain reaction (qPCR) approach to monitor species of particular importance to First Nations collaborators and decision makers, and 2) a metabarcoding approach for assessing community composition using the previously published MiSebastes assay. Both approaches are confounded by the little DNA sequence divergence among species and high sequence variation within species. Overcoming these challenges using a whole mitochondrial approach with the mtGrasp and unikseq pipelines, we generated highly useful eDNA tools. We found that eDNA methods were highly comparable to dive surveys, as both methods indicated a similar ecological reality, including species detections and distributions. Though there are certain species that cannot be distinguished by the MiSebastes assay, eDNA metabarcoding still detected more rockfish species overall. Both eDNA methods show potential for use alongside conventional methods for scalable incorporation into community-based monitoring programs

Hitting probabilities for systems of non-linear stochastic heat equations with multiplicative noise

We consider a system of d non-linear stochastic heat equations in spatial dimension 1 driven by d-dimensional space-time white noise. The non-linearities appear both as additive drift terms and as multipliers of the noise. Using techniques of Malliavin calculus, we establish upper and lower bounds on the one-point density of the solution u(t, x), and upper bounds of Gaussian-type on the two-point density of (u(s, y),u(t, x)). In particular, this estimate quantifies how this density degenerates as (s, y) → (t, x). From these results, we deduce upper and lower bounds on hitting probabilities of the process {u(t,x)}t∈R+,x∈[0,1] , in terms of respectively Hausdorff measure and Newtonian capacity. These estimates make it possible to show that points are polar when d ≥ 7 and are not polar when d ≤ 5. We also show that the Hausdorff dimension of the range of the process is 6 when d > 6, and give analogous results for the processes t↦u(t,x) and x↦u(t,x) . Finally, we obtain the values of the Hausdorff dimensions of the level sets of these processes.R.C. Dalang is supported in part by the Swiss National Foundation for Scientific Research. D. Khoshnevisan’s research is supported in part by a grant from the US National Science Foundation