1,257 research outputs found

    Guided Tissue Remineralization of Resin-Bonded Acid-Etched Dentin

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    Contemporary biomineralization strategies incorporate non-classical crystallization pathways of fluidic amorphous nanoprecursors and mesoscopic transformation. Using two functional biomimetic molecules, we previously regenerated mineralized dentin from acid-etched dentin using the Guided Tissue Remineralization (GTR) approach, with definitive intrafibrillar remineralization of type-I collagen. Degradation of denuded collagen within dentin adhesive resin-infiltrated dentin is a pertinent problem in dentin bonding. Here, we show that GTR provides a means of salvaging these degrading bonds by remineralizing resin-dentin interfaces. The GTR medium consists of a Portland cement/simulated body fluid that includes polyacrylic acid and polyvinylphosphonic acid biomimetic analogs for amorphous calcium phosphate dimension regulation and collagen targeting. Both interfibrillar and intrafibrillar apatites became readily discernible within the adhesive-bonded dentin after 2-4 months. Amorphous nanoprecursors created by GTR also penetrated the adhesive resin matrix to create nanocomposites. We anticipate GTR to be the starting point for more sophisticated strategies in extending the longevity of resin-dentin bonds

    Prediction of Nontrivial Band Topology and Superconductivity in Mg2_2Pb

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    The interplay of BCS superconductivity and nontrivial band topology is expected to give rise to opportunities for creating topological superconductors, achieved through pairing spin-filtered boundary modes via superconducting proximity effects. The thus-engineered topological superconductivity can, for example, facilitate the search for Majorana fermion quasiparticles in condensed matter systems. Here we report a first-principles study of Mg2_2Pb and predict that it should be a superconducting topological material. The band topology of Mg2_2Pb is identical to that of the archetypal quantum spin Hall insulator HgTe, while isostructural and isoelectronic Mg2_2Sn is topologically trivial; a trivial to topological transition is predicted for Mg2_2Sn1−x_{1-x}Pbx_x for x~0.77. We propose that Mg2_2Pb-Mg2_2Sn quantum wells should generate robust spin-filtered edge currents in analogy to HgTe/CdTe quantum wells. In addition, our calculations predict that Mg2_2Pb should become superconducting upon electron doping. Therefore, Mg2_2Pb is expected to provide a practical material platform for studying emergent phenomena arising from the interplay of superconductivity and band topology.Comment: 5 figure

    Virtual Court Study: Report of a Pilot Test 2018

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    This was a pilot study to develop the technological infrastructure for a virtual court or tribunal, get a preliminary idea about how potential users might respond and identify limitations of the technology that would need to be addressed before such options become suitable for regular use. In a ‘virtual’ hearing, there is no physical room for the court (or tribunal) at all: the participants take part by multi-channel video link

    The Nature of Bullying in Higher Education: A Comparative Study of Students’ Experiences in Ghana and Norway

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    The purpose of this study was twofold: (a) to identify the negative behaviors that constitute bullying in higher education as reported by students, and (b) to explore differences in student experiences in two markedly different national contexts. A sample of 1,189 respondents from two universities in Ghana (n = 751) and two universities in Norway (n = 438) answered the same questionnaire. Approximately 40% of the Ghanaian students and 20% of the Norwegian students responded that they had been bullied. Although less frequently observed than in Ghana, relational forms of bullying (e.g., being excluded) were more prevalent in Norway compared to other behaviors. In contrast, direct and verbal forms of bullying, such as name-calling and being taunted, were most common in Ghana. The findings provide insights into cultural and national variations with respect to negative social behaviors related to bullying in the context of higher education.publishedVersionPaid open acces

    Proximal tubule cells stimulated by lipopolysaccharideinhibit macrophage activation

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    Proximal tubule cells stimulated by lipopolysaccharide inhibit macrophage activation.BackgroundTubule cells can produce a variety of cytokines, extracellular matrix (ECM) components, and adhesion molecules in vitro and in vivo. It is generally assumed that stimulated tubule cells are proinflammatory and at least partially responsible for interstitial inflammation. However, the overall effect of tubular cells on interstitial cells is unknown. In this study, pro- and anti-inflammatory cytokine production and net effects on macrophages of tubule cells activated by lipopolysaccharide (LPS) were examined.MethodsTubule cells stimulated with LPS expressed tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-12, monocyte chemoattractant protein-1 (MCP-1), IL-10, and transforming growth factor-β (TGF-β). Conditioned media werecollected from confluent monolayers of rat tubule cells stimulated, or not, by LPS for 4 and 18 hours, respectively. Macrophages were cultured with conditioned media and/or LPS (0.5 μg/mL) for 18 hours.ResultsTNF-α and IL-lβ mRNA of macrophages stimulated by LPS increased more than fivefold when cultured with control conditioned media from unstimulated tubule cells. Surprisingly, TNF-α and IL-lβ levels of macrophages stimulated by LPS were not increased when cultured with conditioned media from activated tubule cells. Neutralizing antibodies to IL-10 and TGF-β were used to define the inhibitory component(s) in conditioned medium. Anti-IL-10, but not anti-TGF-β, abolished partially the inhibitory effects of conditioned media on macrophages.ConclusionTubule cells produce both pro- and anti-inflammatory cytokines and the net effect, partially explained by IL-10, of tubule cells activated with LPS is to inhibit activity of macrophages. Thus, the net effect of activated tubule cells on interstitial pathology may in certain circumstances, be anti- rather than pro-inflammatory

    Spatiotemporal Crime Analysis

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    There has been a rise in the use of visual analytic techniques to create interactive predictive environments in a range of different applications. These tools help the user sift through massive amounts of data, presenting most useful results in a visual context and enabling the person to rapidly form proactive strategies. In this paper, we present one such visual analytic environment that uses historical crime data to predict future occurrences of crimes, both geographically and temporally. Due to the complexity of this analysis, it is necessary to find an appropriate statistical method for correlative analysis of spatiotemporal data, as well as design an interface to present these results to the user in a timely fashion. In our approach, we make use of the Dynamic Covariance Kernel Density Estimation (DCKDE) method to visualize the data in a geospatial context. The results are represented as a heat map showing the areas with a higher probability of crime. In the temporal context, a modified Seasonal Trend decomposition based on Loess (STL) is used to decompose time series signals in order to isolate trends that are used to predict the number of crime occurrences in pre-defined areas for a given time interval. These techniques were applied to Tippecanoe County to make predictions for the next time step. We evaluated the results of our prediction technique against observed data. We note that our methods are applicable to any situation where incidents may have a local spatial correlation

    Role of CD8+ cells in the progression of murine adriamycin nephropathy

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    Role of CD8+ cells in the progression of murine adriamycin nephropathy.BackgroundMany studies have shown that interstitial inflammation in human and experimental renal disease is characterized by T-cell infiltration, but published data on the involvement of inflammatory cell subsets in progressive tubulointerstitial lesions are often conflicting. A previous study suggested a role for cytotoxic T lymphocytes in the damaging effect of CD4+ T-cell depletion in murine adriamycin (ADR) nephropathy, a model of focal segmental glomerulosclerosis (FSGS), and tubulointerstitial inflammation. The aim of this study was to investigate the role of CD8+ cells in this model.MethodsMale BALB/c mice were treated with five intraperitoneal injections of anti-CD8 monoclonal antibody (mAb), beginning from five days after ADR treatment, when overt proteinuria was established. Seven mice in each of groups A (ADR + mAb), B (ADR only), and C (saline treated, age matched) were sacrificed at week 6. Changes in renal function and histopathological features were assessed. Tubulointerstitial inflammation and glomerular inflammation were examined immunohistochemically.ResultsmAb treatment reduced CD8+ cell levels to <2% of normal in spleen. Proteinuria in group A was no different from that in group B at week 6, but was markedly higher than in group C. Creatinine clearance was significantly ameliorated by anti-CD8 treatment (71.8 ± 4.9 μL/min vs. 29.2 ± 2.8 in group B and 81.9 ± 3.7 in group C). Morphometric analysis showed less FSGS in group A compared with group B (6.5 ± 1.9 vs. 13.0 ± 2.8, P < 0.001), as well as less tubular atrophy (indicated by increased ratio of tubule cell height to tubular diameter, 0.25 ± 0.24 in group A vs. 0.04 ± 0.02 in group B, P < 0.05). CD8 depletion also reduced interstitial expansion (6.3 ± 2.2% vs. 16.4 ± 3.1 in group B, P < 0.001) and fibrosis (P < 0.01). Macrophage infiltration in tubulointerstitium was less in group A than in group B (P = 0.052). The number of interstitial CD4+ cells appeared to increase after anti-CD8 treatment, but was not statistically different between groups A and B.ConclusionAnti-CD8 treatment protects against renal functional and structural injury in this murine model of chronic proteinuric renal disease

    Generation of microsatellite repeat families by RTE retrotransposons in lepidopteran genomes

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    <p>Abstract</p> <p>Background</p> <p>Developing lepidopteran microsatellite DNA markers can be problematical, as markers often exhibit multiple banding patterns and high frequencies of non-amplifying "null" alleles. Previous studies identified sequences flanking simple sequence repeat (SSR) units that are shared among many lepidopteran species and can be grouped into microsatellite-associated DNA families. These families are thought to be associated with unequal crossing-over during DNA recombination or with transposable elements (TEs).</p> <p>Results</p> <p>We identified full-length lepidopteran non-LTR retrotransposable elements of the RTE clade in <it>Heliconius melpomene </it>and <it>Bombyx mori</it>. These retroelements possess a single open reading frame encoding the Exonuclease/Endonuclease/Phosphatase and the Reverse Transcriptase/nLTR domains, a 5' UTR (untranslated region), and an extremely short 3' UTR that regularly consists of SSR units. Phylogenetic analysis supported previous suggestions of horizontal transfer among unrelated groups of organisms, but the diversity of lepidopteran RTE elements appears due to ancient divergence of ancestral elements rather than introgression by horizontal transfer. Similarity searches of lepidopteran genomic sequences in GenBank identified partial RTE elements, usually consisting of the 3' terminal region, in 29 species. Furthermore, we identified the C-terminal end of the Reverse Transcriptase/nLTR domain and the associated 3' UTR in over 190 microsatellite markers from 22 lepidopteran species, accounting for 10% of the lepidopteran microsatellites in GenBank. Occasional retrotransposition of autonomous elements, frequent retrotransposition of 3' partial elements, and DNA replication slippage during retrotransposition offers a mechanistic explanation for the association of SSRs with RTE elements in lepidopteran genomes.</p> <p>Conclusions</p> <p>Non-LTR retrotransposable elements of the RTE clade therefore join a diverse group of TEs as progenitors of SSR units in various organisms. When microsatellites are isolated using standard SSR enrichment protocols and primers designed at complementary repeated regions, amplification from multiple genomic sites can cause scoring difficulties that compromise their utility as markers. Screening against RTE elements in the isolation procedure provides one strategy for minimizing this problem.</p
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