277 research outputs found

    Spectrophotometric assessment of the effectiveness of Opalescence PF 10%: a 14-month clinical study

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    Objectives: To evaluate the effectiveness of Opalescence PF 10% just after treatment, at 6-month follow-up and at a 14-month follow-up period. Methods: Opalescence PF 10% was applied nightly for 14 days. The color of teeth 11 and 21 of 17 subjects were measured with a spectrophotometer (L*; a*; b*) before treatment, just after treatment (14 days), after 6 months and after 14 months. Subjects were instructed to take note of any tooth sensitivity. Results: For all three components (L*, a* and b*) statistical significant differences (p < 0.05) in the values between base-line, after treatment (14 days later), after 6 months and after 14 months were found (Wilcoxon Signed Rank Sum Test). The decrease in L* was about 20% after 6 months and about 50% after 14 months. The a* value decreased approximately 14% after 6 months but was worse after 14 months than at the beginning. The b* value decreased the least with about 9% after 6 months and about 8% after 14 months. The decrease in View the MathML source was ∼20% after 14 months. Less than 20% of the subjects experienced mild tooth sensitivity just after treatment. Conclusion: Significantly whiter teeth were found after treatment as well as after a 6-month follow-up period. The whiteness/brightness (L*) decreased with ∼50% after 14 months and the a* value with ∼50% after 7 months, while the yellowness (b* value) remained even after 14 months. Clinical implications: The product is an effective tooth whitener resulting in only low tooth sensitivity. Re-bleaching could be done at about 14 months.Web of Scienc

    Mid-infrared imaging and spectroscopy of the enigmatic cocoon stars in the Quintuplet Cluster

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    In an attempt to determine the nature of the enigmatic cocoon stars in the Quintuplet Cluster, we have obtained mid-infrared imaging and spectrophotometry of the cluster, using the CAM and SWS instruments on ISO, using SpectroCam-10 on the Palomar 5m telescope, and NICMOS on HST. The spectra show smooth continua with various dust and ice absorption features. These features are all consistent with an interstellar origin, and there is no clear evidence for any circumstellar contribution to these features. We find no spectral line or feature that could elucidate the nature of these sources. Detailed modeling of the silicate absorption features shows that they are best reproduced by the mu Cep profile, which is typical of the interstellar medium, with tau(sil) \sim 2.9. The high spatial resolution mid-IR images show that three of the five cocoon stars have spatially extended and asymmetric envelopes, with diameters of \sim 20,000 AUs. A reddening law similar to that of Lutz (1999) but with silicate features based on the mu Cep profile and normalized to our value of tau(sil) is used to deredden the observed spectrophotometry. The dereddened energy distributions are characterised by temperatures of 750-925 K, somewhat cooler than determined from near IR data alone. Models of optically thin and geometrically thick dust shells, as used by Williams et al. (1987) for very dusty, late-type WC stars, reproduce the observed SEDs from 4 to 17 mic, and imply shell luminosities of log(L/L(sun)) \sim 4.5-4.9 for the brightest four components. An analysis of the various suggestions proposed to explain the nature of the cocoon stars reveals serious problems with all the hypotheses, and the nature of these sources remains an enigma.Comment: 16 pages, 11 figures, A&A style. Accepted by A&

    An oligonucleotide microarray for transcriptome analysis of Schistosoma mansoni and its application/use to investigate gender-associated gene expression

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    Global profiling transcriptomes of parasitic helminths offers the potential to simultaneously identify co-ordinately expressed genes, novel genetic programs and uniquely utilized metabolic pathways, which together provide an extensive and new resource for vaccine and drug discovery. We have exploited this post-genomic approach to fabricate the first oligonucleotide DNA microarray for gene expression analysis of the parasitic trematode Schistosoma mansoni. A total of 17,329 S. mansoni DNA sequences were used to design a microarray consisting of 7335 parasite elements or approximately 50% of this parasite's transcriptome. Here, we describe the design of this new microarray resource and its evaluation by extending studies into gender-associated gene expression in adult schistosomes. We demonstrate a high degree of reproducibility in detecting transcriptional differences among biologically replicated experiments and the ability of the microarray to distinguish between the expression of closely related gene family members. Importantly, for issues related to sexual dimorphism, labour division, gamete production and drug target discovery, 197 transcripts demonstrated a gender-biased pattern of gene expression in the adult schistosome, greatly extending the number of sex-associated genes. These data demonstrate the power of this new resource to facilitate a greater understanding into the biological complexities of schistosome development and maturation useful for identifying novel intervention strategies

    Defining a 3-dimensional trishear parameter space to understand the temporal evolution of fault propagation folds

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    The application of trishear, in which deformation occurs in a triangular zone in front of a propagating fault tip, is often used to understand fault related folding. A key element of trishear, in comparison to kink-band methods, is that non-uniform deformation within the triangle zone allows the layer thickness and length to change during deformation. By varying three controlling parameters independently (trishear propagation/slip ratio, trishear apical angle and fault dip), we construct a three-dimensional parameter space to demonstrate the variability of resultant geometry feasible with trishear. We plot published natural examples in this parameter space and identify two clusters and show that the most applicable typical trishear propagation/slip ratio is 2to3, while the trishear apical angle varies from 30° to 100°. We propose that these findings can help estimate the best-fit parameters for natural structures. We then consider the temporal evolution of specific geometric examples and factors that increase the complexity of trishear including: (1) fault-dip changes and (2) pre-existing faults.To illustrate the applicability of the parameter space and complex trishear models to natural examples, we apply our results to a sub-surface example from the Qaidam basin in northern Tibetan Plateau

    Seismicity and subsidence following the 2011 Nabro eruption, Eritrea: insights into the plumbing system of an off-rift volcano

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    Nabro volcano, situated to the east of the Afar Rift Zone, erupted on 12 June 2011. Eruptions at such off-rift volcanoes are infrequent, and consequently, the plumbing systems are poorly understood. We present posteruption Synthetic Aperture Radar (SAR) images from the TerraSAR-X satellite and posteruption continuous seismic activity from a local seismic array. Interferometric analysis of SAR data, reveals a circular, 12 km wide, signal subsiding at ∼200 mm/yr. We inverted for the best fit Mogi source finding a 4 ± 1 × 107 m3/yr volume decrease at 7 ± 1 km depth. Between 31 August and 7 October 2011, we located 658 and relocated 456 earthquakes with local magnitudes between −0.4 and 4.5. Seismicity beneath the SE edge of Nabro at 11 km depth is likely associated with high strain rates from deep magma flow into the modeled reservoir. This suggests that magma is supplied through a narrow conduit and then stored at ∼7 km depth. We interpret seismicity at 4–6 km depth as brittle fracturing above the inferred magma reservoir. Focal mechanisms delineate a thrust fault striking NE-SW and dipping 45° to the SE across the caldera floor. We propose that the crustal response is to slip on this fault which crosscuts the caldera rather than to deform on ring faults. The NE-SW fault plane is not associated with measurable surface deformation, indicating that it does not contribute much to the caldera deformation. We show that subsidence of the caldera is controlled by magma chamber processes rather than fault slip

    Clothing, race and identity : sumptuary laws in colonial Spanish America

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    On holidays and other festive occasions, Andean peoples in the Spanish Viceroyalty of Peru liked to dress up. According to sixteenth - century documents, wealthy Amerindians in Lima, Quito and other colonial cities enjoyed wearing a combination of European and Andean garments, sometimes made of silk and other expensive, imported fabrics. Their sartorial exuberance annoyed local Spaniards, who issued repeated orders prohibiting Amerindians from wearing a range of garments containing silk, velvet, Holland cloth, lace and other embellishments. The indigenous elite did not accept these prohibitions without protest. In 1593, members of the Amerindian community in Quito wrote to Emperor Philip II to complain that ‘as conquered people it sometimes happens that officials and other people undress them and take their clothing, saying that they can wear only cotton, which causes them much trouble and vexation

    Food-associated cues alter forebrain functional connectivity as assessed with immediate early gene and proenkephalin expression

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    <p>Abstract</p> <p>Background</p> <p>Cues predictive of food availability are powerful modulators of appetite as well as food-seeking and ingestive behaviors. The neurobiological underpinnings of these conditioned responses are not well understood. Monitoring regional immediate early gene expression is a method used to assess alterations in neuronal metabolism resulting from upstream intracellular and extracellular signaling. Furthermore, assessing the expression of multiple immediate early genes offers a window onto the possible sequelae of exposure to food cues, since the function of each gene differs. We used immediate early gene and proenkephalin expression as a means of assessing food cue-elicited regional activation and alterations in functional connectivity within the forebrain.</p> <p>Results</p> <p>Contextual cues associated with palatable food elicited conditioned motor activation and corticosterone release in rats. This motivational state was associated with increased transcription of the activity-regulated genes <it>homer1a</it>, <it>arc</it>, <it>zif268</it>, <it>ngfi-b </it>and c-<it>fos </it>in corticolimbic, thalamic and hypothalamic areas and of proenkephalin within striatal regions. Furthermore, the functional connectivity elicited by food cues, as assessed by an inter-regional multigene-expression correlation method, differed substantially from that elicited by neutral cues. Specifically, food cues increased cortical engagement of the striatum, and within the nucleus accumbens, shifted correlations away from the shell towards the core. Exposure to the food-associated context also induced correlated gene expression between corticostriatal networks and the basolateral amygdala, an area critical for learning and responding to the incentive value of sensory stimuli. This increased corticostriatal-amygdalar functional connectivity was absent in the control group exposed to innocuous cues.</p> <p>Conclusion</p> <p>The results implicate correlated activity between the cortex and the striatum, especially the nucleus accumbens core and the basolateral amygdala, in the generation of a conditioned motivated state that may promote excessive food intake. The upregulation of a number of genes in unique patterns within corticostriatal, thalamic, and hypothalamic networks suggests that food cues are capable of powerfully altering neuronal processing in areas mediating the integration of emotion, cognition, arousal, and the regulation of energy balance. As many of these genes play a role in plasticity, their upregulation within these circuits may also indicate the neuroanatomic and transcriptional correlates of extinction learning.</p
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