1,704 research outputs found

    Comparison of marginal fit of lithium disilicate crowns fabricated with CAD-CAM technology using conventional impressions and two intra-oral digital scanners.

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    The use of digital impression techniques in dental crown fabrication is increasing. It is important these techniques yield prosthesis of equal or better accuracy compared to conventional techniques. This study compared marginal gap size in crowns fabricated by conventional and digital impression methods. One typodont maxillary right central incisor was prepared for an all-ceramic crown. Ten impressions were made with each method: conventional using polyvinyl siloxane impression material, digital impressions using the Lava C.O.S. (3M ESPE), and iTero (Cadent) intraoral scanning devices. Lithium disilicate crowns were fabricated and marginal gap measured for each using an optical microscope. There was no significant difference between average gap size in all groups. However, though not statistically significant, the conventional group average gap size was about 23µm larger compared to the digital groups. Within the limitations of this study, the digital and conventional impressions were found to produce crown crowns with similar marginal accuracy

    Fostering Community Health and Well-Being through the Development of a Mindfulness Program and Meditation Space at the University of Miami Libraries

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    This paper offers a case study in the development of a mindfulness program and meditation space within the context of a university research library in the United States. In 2016, thanks to a collaboration with the University of Miami Mindfulness-in-Law Program, the University of Miami (UM) Libraries began offering weekly mindfulness sessions for the benefit of the University community and with the goal of supporting community health and well-being. Appropriate for novice meditators and led by mindfulness researchers and certified teachers, these sessions offer guided meditations and talks that cultivate awareness and compassion. Attendees also have the opportunity to ask questions and learn from other participants. Following the onset of the COVID-19 pandemic in spring of 2020, the mindfulness sessions shifted from in-person to online. As a result, the sessions attracted an increased number of participants, and these sessions continue online to the present day

    Flexible Forage Systems for Variable Water Supplies

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    The dairy industry in northern Victoria, Australia is primarily based on the border check irrigation of temperate forage species over the spring to autumn period. Traditionally, dairy cows have grazed the perennial species (white clover and perennial ryegrass) and annual pastures (based on short-lived ryegrasses and subterranean or Persian clover). However, due to a more variable climate – particularly a period where the annual rainfall has been significantly less than the long-term average – the summer irrigation allocations have been substantially lower and more variable than the preceding 20-30 years. Under this climate scenario, dairy farmers are re-evaluating their feed base to ensure that they are optimising forage production under conditions of less water (both rainfall and irrigation - Greenwood et al. 2006; Lawson and Kelly 2007). Research at the Department of Primary Industries at Tatura in northern Victoria is focussing on identifying forage species and management systems that are better adapted to the predicted future climate (of higher summer temperatures and greater plant water stress) than perennial ryegrass. Research on lucerne is evaluating the flexibility of this species to perform when both rainfall and irrigation vary greatly across seasons and years. The aim of research on tall fescue is to develop an effective grazing management system that will capitalise on its high dry matter potential through the summer

    The Response of Selected Temperate Forages to Increasing Summer Drought Conditions and High Summer Temperatures in Northern Victoria, Australia

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    In the dairy region of northern Victoria, Australia, the performance of temperate perennial dairy pastures is often poor over summer due to a combination of high temperatures and limited water availability that can restrict dry matter production and plant survival. A series of field experiments examined the effects of heat and restricted irrigation (as a consequence of drought) on the growth and nutritive characteristics of selected forage species, and whether survival under experimental conditions was influenced by plant genotype, irrigation and grazing management strategies, as well as endophyte presence. The major focus was on perennial ryegrass. Detailed sampling of perennial ryegrass (Lolium perenne L.), lucerne (Medicago sativa L.) and tall fescue (Festuca arundinacea Schreb) pastures on commercial farms during five extreme heat events (\u3e 35 oC) over summer 2018/2019, highlighted the impact of high temperatures on pasture nutritive parameters. In vitro dry matter digestibility and water soluble carbohydrate concentrations decreased by 0.2% units per degree rise in average maximum daily temperature from 23 to 40 ÂşC and neutral detergent fibre and acid detergent fibre concentrations increased by 0.2% and 0.15% units per degree, respectively. When a range of perennial ryegrass cultivars, hybrid ryegrasses and tall fescue cultivars were evaluated under full and restricted irrigation and two grazing strategies, few differences in net pasture accumulation over summer or survival were observed. The research highlighted the importance of maintaining plant density during periods of restricted irrigation to ensure plant recovery once irrigation or rainfall becomes available. No endophyte-ryegrass combinations were found to be better adapted to restricted water and high temperature conditions. The incidences of extreme heat events and low water availability are increasing in northern Victoria and this research will assist farmers to identify strategies to mitigate the negative effect of these conditions on the production and feed quality of perennial ryegrass-based pastures

    New procedures for testing whether stock price processes are martingales

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    We propose procedures for testing whether stock price processes are martingales based on limit order type betting strategies. We first show that the null hypothesis of martingale property of a stock price process can be tested based on the capital process of a betting strategy. In particular with high frequency Markov type strategies we find that martingale null hypotheses are rejected for many stock price processes

    Loss of Upc2p-Inducible ERG3 Transcription Is Sufficient To Confer Niche-Specific Azole Resistance without Compromising Candida albicans Pathogenicity

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    Inactivation of sterol Δ5,6-desaturase (Erg3p) in the prevalent fungal pathogen Candida albicans is one of several mechanisms that can confer resistance to the azole antifungal drugs. However, loss of Erg3p activity is also associated with deficiencies in stress tolerance, invasive hyphal growth, and attenuated virulence in a mouse model of disseminated infection. This may explain why relatively few erg3-deficient strains have been reported among azole-resistant clinical isolates. In this study, we examined the consequences of Erg3p inactivation upon C. albicans pathogenicity and azole susceptibility in mouse models of mucosal and disseminated infection. While a C. albicans erg3Δ/Δ mutant was unable to cause lethality in the disseminated model, it induced pathology in a mouse model of vaginal infection. The erg3Δ/Δ mutant was also more resistant to fluconazole treatment than the wild type in both models of infection. Thus, complete loss of Erg3p activity confers azole resistance but also niche-specific virulence deficiencies. Serendipitously, we discovered that loss of azole-inducible ERG3 transcription (rather than complete inactivation) is sufficient to confer in vitro fluconazole resistance, without compromising C. albicans stress tolerance, hyphal growth, or pathogenicity in either mouse model. It is also sufficient to confer fluconazole resistance in the mouse vaginal model, but not in the disseminated model of infection, and thus confers niche-specific azole resistance without compromising C. albicans pathogenicity at either site. Collectively, these results establish that modulating Erg3p expression or activity can have niche-specific consequences on both C. albicans pathogenicity and azole resistanc

    Defining Components of the Ăźcatenin Destruction Complex and Exploring Its Regulation and Mechanisms of Action during Development

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    A subset of signaling pathways play exceptionally important roles in embryonic and post-embryonic development, and mis-regulation of these pathways occurs in most human cancers. One such pathway is the Wnt pathway. The primary mechanism keeping Wnt signaling off in the absence of ligand is regulated proteasomal destruction of the canonical Wnt effector ßcatenin (or its fly homolog Armadillo). A substantial body of evidence indicates that SCF(βTrCP) mediates βcat destruction, however, an essential role for Roc1 has not been demonstrated in this process, as would be predicted. In addition, other E3 ligases have also been proposed to destroy βcat, suggesting that βcat destruction may be regulated differently in different tissues.Here we used cultured Drosophila cells, human colon cancer cells, and Drosophila embryos and larvae to explore the machinery that targets Armadillo for destruction. Using RNAi in Drosophila S2 cells to examine which SCF components are essential for Armadillo destruction, we find that Roc1/Roc1a is essential for regulating Armadillo stability, and that in these cells the only F-box protein playing a detectable role is Slimb. Second, we find that while embryonic and larval Drosophila tissues use the same destruction complex proteins, the response of these tissues to destruction complex inactivation differs, with Armadillo levels more elevated in embryos. We provide evidence consistent with the possibility that this is due to differences in armadillo mRNA levels. Third, we find that there is no correlation between the ability of different APC2 mutant proteins to negatively regulate Armadillo levels, and their recently described function in positively-regulating Wnt signaling. Finally, we demonstrate that APC proteins lacking the N-terminal Armadillo-repeat domain cannot restore Armadillo destruction but retain residual function in negatively-regulating Wnt signaling.We use these data to refine our model for how Wnt signaling is regulated during normal development

    The evolution of azole resistance in Candida albicans sterol 14α-demethylase (CYP51) through incremental amino acid substitutions

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    Recombinant Candida albicans CYP51 (CaCYP51) proteins containing 23 single and 5 double amino acid substitutions found in clinical strains and the wild-type enzyme were expressed in Escherichia coli and purified by Ni2+-nitrilotriacetic acid agarose chromatography. Catalytic tolerance to azole antifungals was assessed by determination of the concentration causing 50% enzyme inhibition (IC50) using CYP51 reconstitution assays. The greatest increase in the IC50 compared to that of the wild-type enzyme was observed with the five double substitutions Y132F+K143R (15.3-fold), Y132H+K143R (22.1-fold), Y132F+F145L (10.1-fold), G307S+G450E (13-fold), and D278N+G464S (3.3-fold). The single substitutions K143R, D278N, S279F, S405F, G448E, and G450E conferred at least 2-fold increases in the fluconazole IC50, and the Y132F, F145L, Y257H, Y447H, V456I, G464S, R467K, and I471T substitutions conferred increased residual CYP51 activity at high fluconazole concentrations. In vitro testing of select CaCYP51 mutations in C. albicans showed that the Y132F, Y132H, K143R, F145L, S405F, G448E, G450E, G464S, Y132F+K143R, Y132F+F145L, and D278N+G464S substitutions conferred at least a 2-fold increase in the fluconazole MIC. The catalytic tolerance of the purified proteins to voriconazole, itraconazole, and posaconazole was far lower and limited to increased residual activities at high triazole concentrations for certain mutations rather than large increases in IC50 values. Itraconazole was the most effective at inhibiting CaCYP51. However, when tested against CaCYP51 mutant strains, posaconazole seemed to be the most resistant to changes in MIC as a result of CYP51 mutation compared to itraconazole, voriconazole, or fluconazole

    Neonatal brain tissue classification with morphological adaptation and unified segmentation

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    Measuring the distribution of brain tissue types (tissue classification) in neonates is necessary for studying typical and atypical brain development, such as that associated with preterm birth, and may provide biomarkers for neurodevelopmental outcomes. Compared with magnetic resonance images of adults, neonatal images present specific challenges that require the development of specialized, population-specific methods. This paper introduces MANTiS (Morphologically Adaptive Neonatal Tissue Segmentation), which extends the unified segmentation approach to tissue classification implemented in Statistical Parametric Mapping (SPM) software to neonates. MANTiS utilizes a combination of unified segmentation, template adaptation via morphological segmentation tools and topological filtering, to segment the neonatal brain into eight tissue classes: cortical gray matter, white matter, deep nuclear gray matter, cerebellum, brainstem, cerebrospinal fluid (CSF), hippocampus and amygdala. We evaluated the performance of MANTiS using two independent datasets. The first dataset, provided by the NeoBrainS12 challenge, consisted of coronal T2-weighted images of preterm infants (born ≤30 weeks’ gestation) acquired at 30 weeks’ corrected gestational age (n= 5), coronal T2-weighted images of preterm infants acquired at 40 weeks’ corrected gestational age (n= 5) and axial T2-weighted images of preterm infants acquired at 40 weeks’ corrected gestational age (n= 5). The second dataset, provided by the Washington University NeuroDevelopmental Research (WUNDeR) group, consisted of T2-weighted images of preterm infants (born <30 weeks’ gestation) acquired shortly after birth (n= 12), preterm infants acquired at term-equivalent age (n= 12), and healthy term-born infants (born ≥38 weeks’ gestation) acquired within the first nine days of life (n= 12). For the NeoBrainS12 dataset, mean Dice scores comparing MANTiS with manual segmentations were all above 0.7, except for the cortical gray matter for coronal images acquired at 30 weeks. This demonstrates that MANTiS’ performance is competitive with existing techniques. For the WUNDeR dataset, mean Dice scores comparing MANTiS with manually edited segmentations demonstrated good agreement, where all scores were above 0.75, except for the hippocampus and amygdala. The results show that MANTiS is able to segment neonatal brain tissues well, even in images that have brain abnormalities common in preterm infants. MANTiS is available for download as an SPM toolbox from http://developmentalimagingmcri.github.io/mantis
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