337 research outputs found

    Phototauntomerism of o-nitrobenzyl compounds: o-quinonoid aci-nitro species studied by matrix isolation and DFT calculations

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    Photolyses of 2-nitrobenzyl methyl ether and 2-nitrotoluene with 254 nm light have been investigated in Ar and N2 matrices at 12 K, and have been found to give o-quinonoid aci-nitro species as the primary photoproducts, along with other products. The o-quinonoid species have UV absorptions at relatively long wavelengths (λmax at 385–430 nm) and undergo facile secondary photolysis when irradiated in these absorption bands. By means of this selective photolysis, fairly complete IR spectra of the o-quinonoids have been obtained. Comparison of the matrix IR spectra of these species with simulated spectra computed using density functional theory (DFT) has confirmed the identity of these reactive intermediates. Moreover, detailed analysis of the fit between the computed and experimental IR spectra has allowed the specific stereoisomers generated to be identified with reasonable confidence. Computations have also been made of the relative energies of the starting compounds, intermediate o-quinonoid isomers and the possible secondary products, together with the transition states connecting them. The results of these computations indicate that the observed stereoisomer of each of the o-quinonoid species cannot arise by photoinduced H-atom transfer followed by isomerizations on the electronic ground-state surfaces, since the energy barriers for reversion to starting compounds are substantially lower than those for the necessary isomerizations. It is therefore concluded that H-atom transfer and conformational interconversion occur in an electronic excited state

    Single Miller Class III recession treatment in the anterior maxilla

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    Introduction: Miller’s Class III gingival recession represents a challenging condition with a low predictability in order to obtain successful outcomes. The purpose of this case report is to document the management of an isolated Class III gingival recession (Rec) with Coronally Advanced Flap in combination with Subepithelial Connective Tissue Graft. Presentation of the case: A 45 years-old female with a 2 mm Rec associated with interproximal attachment loss at the upper left canine requested a dental cosmetic treatment for this area. A bilaminar technique was performed in order to solve the aesthetic impairment. Results at short (1 year) and long term (10 years) are reported. Discussion: At 1-year follow up a complete root coverage with no interproximal attachment loss was observed, with an increased amount of keratinized tissue width and thickness. Optimal aesthetic outcome was accomplished with complete patient satisfaction. However, at 10-year follow-up 1mm Rec on mesio-buccal and buccal sites associated to a non-carious cervical lesion (NCCL) were noticed, associated with a bruxism pattern in combination with a relapse of traumatic brushing technique and vigorous use of interdental brushes. At this time, reinstruction to the appropriate domiciliary oral hygiene procedures and a composite restoration were performed in order to solve the clinical condition. Conclusion: At 1-year follow-up Rec associated to attachment loss and NCCL can be successfully managed by means of bilaminar technique and conservative restorations. However, a careful assessment of prognostic factors must be considered in order to achieve successful treatment outcomes in the long-term

    Periodontitis and vascular inflammatory biomarkers: an experimental in vivo study in rats

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    The objective of this preclinical in vivo study was to determine changes in vascular inflammatory biomarkers in systemic circulation after injection of lipopolysaccharide (LPS) from Porphyromonas gingivalis (Pg) in rats. Experimental periodontitis was induced by injections of Pg-LPS. Gingival soft and hard tissues changes were analysed by means of magnetic resonance imaging and micro computed tomography. Serum levels of interleukin (IL)-6, IL-10, pentraxin (PTX) 3, and soluble fragment of tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) were determined at baseline and 24 h, 7, 14, and 21 days after periodontal induction. Significant periodontal inflammation and alveolar bone loss were evident at the end of periodontal induction. Experimental periodontitis posed an acute systemic inflammatory response with increased serum levels of IL-6 and PTX3 at 24 h post-induction, followed by a significant overexpression of sTWEAK at 7 days. This inflammatory state was maintained until the end of the experiment (21 days). As expected, IL-10 serum levels were significantly lower during the follow-up compared to baseline concentrations. In the present animal model, experimental periodontitis is associated with increased systemic inflammation. Further studies are needed to confirm whether PTX3 and sTWEAK could be useful biomarkers to investigate potential mechanisms underlying the relationship between periodontitis and atherosclerotic vascular diseases

    Formation and evolution of back-barrier perched lakes in rocky coasts: an example of a Holocene system in NW Spain

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    Coastal back-barrier perched lakes are freshwater bodies that are elevated over sea-level and are not directly subjected to the inflow of sea-water. This study provides a detailed reconstruction of the Doniños back-barrier perched lake that developed at the end of a small river valley in the rocky coast of the northwest Iberian Peninsula during the Holocene transgression. Its sequence stratigraphy was reconstructed based on a core transect across the system, the analyses of its lithofacies and microfossil assemblages, and a high-resolution radiocarbon-based chronology. The Doniños perched lake was formed ca. 4.5 ka BP. The setting of the perched lake was favoured by Late Holocene sea-level stabilization and the formation of a barrier and back-barrier basin, which was contemporaneous with the high systems tract period. This basin developed over marine and lagoonal sediments deposited between 10.2 and 8.0 ka BP, during rapidly rising sea-level characteristic of the transgressive systems track period. At 1.1 ka BP, the barrier was breached and the perched lake was partially emptied, causing the erosion of the back-barrier basin sediments and a significant sedimentary hiatus. Both enhanced storminess and human intervention were likely responsible for this event. After 1 ka BP, the barrier reclosed and the present-day lake was reformed, with the water level reaching as high as 5 m amsl. The depositional evolution of the Doniños system serves as a model of coastal back-barrier perched lakes in coastal clastic systems that have developed over gently seaward-dipping rugged substrates at small distances from the shoreline and under conditions of rising sea-level and high sediment supply. A review of estuaries, back-barrier lagoons, pocket beaches and back-barrier perched lakes in the rocky coast of the northwest Spain shows that the elevation of the bedrock is the main factor controlling the origin and evolution of these systems

    Nonequilibrium Casimir pressures in liquids under shear

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    In stationary nonequilibrium states coupling between hydrodynamic modes causes thermal fluctuations to become long ranged inducing nonequilibrium Casimir pressures. Here we consider nonequilibrium Casimir pressures induced in liquids by a velocity gradient. Specifically, we have obtained explicit expressions for the magnitude of the shear-induced pressure enhancements in a liquid layer between two horizontal plates that complete and correct results previously presented in the literature. In contrast to nonequilibrium Casimir pressures induced by a temperature or concentration gradient, we find that in shear nonequilibrium contributions from short-range fluctuations are no longer negligible. In addition, it is noted that currently available computer simulations of model fluids in shear observe effects from molecular correlations at nanoscales that have a different physical origin and do not probe shear-induced pressures resulting from coupling of long-wavelength hydrodynamic modes. Even more importantly, we find that in actual experimental conditions, shear-induced pressure enhancements are caused by viscous heating and not by thermal velocity fluctuations. Hence, isothermal computer simulations are irrelevant for the interpretation of experimental shear-induced pressure enhancements

    Assessment of information resources for people with hypodontia

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    Aim: To assess the adequacy of patient information to support understanding and decision-making for people affected by hypodontia. Methods: 1) Questionnaire to understand the provision of patient information by dentists; 2) Systematic search to identify online open-access patient information; 3) Quality assessment of written patient information. Results: Questionnaire response rate was 49% (319/649); 91% examined and/or treated people with hypodontia. Most general dentists referred patients to specialist services without providing written hypodontia information. The majority of dental specialists provide patient leaflets but less than a third used web-resources. Only 19% of respondents felt current resources were fit-for-purpose. Thirty-one patient resources (18 leaflets and 13 online) were assessed against quality criteria. The aim of the resource was seldom explicit, the content was often incomplete and variation in readability scores indicated high levels of literacy were required. Discussion: Access to, and quality of, patient information for hypodontia is inadequate. Current resources are not sufficiently comprehensive to prepare young patients to engage in shared dental care decisions with their parents and/or dental professionals. Conclusion: There is a need for improved access to, and provision of, information about hypodontia if dental professionals want to meet best practice guidance and involve patients in shared decision-making

    Temporal profile of body temperature in acute ischemic stroke: relation to stroke severity and outcome

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    BACKGROUND: Pyrexia after stroke (temperature ≥37.5°C) is associated with poor prognosis, but information on timing of body temperature changes and relationship to stroke severity and subtypes varies. METHODS: We recruited patients with acute ischemic stroke, measured stroke severity, stroke subtype and recorded four-hourly tympanic (body) temperature readings from admission to 120 hours after stroke. We sought causes of pyrexia and measured functional outcome at 90 days. We systematically summarised all relevant previous studies. RESULTS: Amongst 44 patients (21 males, mean age 72 years SD 11) with median National Institute of Health Stroke Score (NIHSS) 7 (range 0–28), 14 had total anterior circulation strokes (TACS). On admission all patients, both TACS and non-TACS, were normothermic (median 36.3°C vs 36.5°C, p=0.382 respectively) at median 4 hours (interquartile range, IQR, 2–8) after stroke; admission temperature and NIHSS were not associated (r(2)=0.0, p=0.353). Peak temperature, occurring at 35.5 (IQR 19.0 to 53.8) hours after stroke, was higher in TACS (37.7°C) than non-TACS (37.1°C, p<0.001) and was associated with admission NIHSS (r(2)=0.20, p=0.002). Poor outcome (modified Rankin Scale ≥3) at 90 days was associated with higher admission (36.6°C vs. 36.2°C p=0.031) and peak (37.4°C vs. 37.0°C, p=0.016) temperatures. Sixteen (36%) patients became pyrexial, in seven (44%) of whom we found no cause other than the stroke. CONCLUSIONS: Normothermia is usual within the first 4 hours of stroke. Peak temperature occurs at 1.5 to 2 days after stroke, and is related to stroke severity/subtype and more closely associated with poor outcome than admission temperature. Temperature-outcome associations after stroke are complex, but normothermia on admission should not preclude randomisation of patients into trials of therapeutic hypothermia

    Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

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    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

    Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

    Get PDF
    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

    Parental Leave policies, gender equity and family well being in Europe: a comparative perspective

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    Leave policies and the protection of working parents' rights have changed significantly in Europe during the last few decades. While policies introduced immediately after World War II were largely based on a male-breadwinner model, the post-1970s policies have recognised the increase in maternal employment, the growing diversity of work/family arrangements and working parents' needs for state support in caring for young children. Paid maternity leave and paid or unpaid parental leave are now available throughout Europe - Western, Central and Eastern - and policy developments have encouraged more gender-neutral leaves and longer periods of paid leave (Deven and Moss 2005)
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