Crystal growth on enamel in relation to acid etching

Crystal formation may occur during etching of enamel surfaces with phosphoric acid. In this in vitro study we observed, from a morphological standpoint, some crystals left after etching, on the surfaces, using the scanning electron microscope. More often, after water-spraying, a thin generalized precipitate remains on the surface. This precipitate may be harmful for the retention of composite resins. On few specimens we obtained needle-shaped or petal-like crystals. Crystal deposits were spread evenly, on the surface, or nucleated from different points. We tempted to identify these crystal formations by X-ray diffraction and microprobe analysis. Chemical identification seems very important because calcium phosphates solubility varies. Crystal dissolution in saliva can lead to marginal leakage and impairs the quality of esthetic restorations. On the contrary insoluble crystals may ensure microscopic retentions and crystal growth is now considered as an alternative for enamel pretreatment in bracket bonding. Crystal formation, in these first experiments, is too scarse to be used for crystal bonding. But it appears that two factors may enhance the crystal number: a preliminary topical application of fluoride and adsorption of an acidic protein, on the surface, before etching. However, further investigations are still necessary.On peut observer la formation de cristaux, à la surface de l’émail, après un mordançage à l’acide phosphorique.Dans cette étude, effectuée in vitro, nous avons observé, en M.E.B., d’un point de vue strictement morphologique un certain nombre de cristallisations déposées, à la surface de l’émail, après mordançage.Le plus souvent, après rinçage, persiste en surface un fin précipité; celui-ci est généralement considéré comme néfaste pour la bonne tenue des résines composites. Sur quelques échantillons nous avons obtenu des cristaux en forme d’aiguilles ou de larges pétales. Ces cristaux peuvent être disposés au hasard ou regroupés autour d’un centre de nucléation. Nous avons essayé d’identifier certains de ces cristaux en pratiquant une analyse en microsonde et une diffraction aux rayons X. Il paraît très important de connaître la nature chimique de ces cristaux car les différents sels phospho-calciques ont des taux de solubilité variables. A long terme, la dissolution de ces cristaux, dans la salive peut conduire à la formation d’un hiatus qui risque de compromettre la qualité esthétique des restaurations. Au contraire, de telles cristallisations, si elles s’avéraient insolubles pourraient constituer des microrétentions. La croissance d’une phase cristalline, à la surface de l’émail, étant déjà considérée comme une alternative valable au mordançage, en orthopédie dento-faciale pour le collage des verrous. D’après les résultats de cette étude préliminaire il semble que la formation de cristaux soit encore trop aléatoire pour favoriser la rétention des résines. Deux facteurs semblent favoriser cette formation de cristaux: l’application topique préalable, sur l’émail, d’un fluorure et l’adsorption d’une protéine acide (ici, l’albumine) avant mordançage. Il semble toutefois que ces observations doivent être confirmées

Comprehensive analysis of fibroblast growth factor receptor expression patterns during chick forelimb development

Specific interactions between fibroblast growth factors (Fgf1-22) and their tyrosine kinase receptors (FgfR1-4) activate different signalling pathways that are responsible for the biological processes in which Fgf signalling is implicated during embryonic development. In the chick, several Fgf ligands (Fgf2, 4,8, 9, 10, 12, 13 and 18) and the four FgfRs (FgfR 1, 2, 3 and 4) have been reported to be expressed in the developing limb. The precise spatial and temporal expression of these transcripts is important to guide the limb bud to develop into a wing/leg. In this paper, we present a detailed and systematic analysis of the expression patterns of FgfR1, 2, 3 and 4 throughout chick wing development, by in situ hybridisation on whole mounts and sections. Moreover, we characterize for the first time the different isoforms of FGFR1-3 by analysing their differential expression in limb ectoderm and mesodermal tissues, using RT-PCR and in situ hybridisation on sections. Finally, isoform-specific sequences for FgfR1IIIb, FgfR1IIIc, FgfR3IIIb and FgfR3IIIc were determined and deposited in GenBank with the following accession numbers: GU053725, GU065444, GU053726, GU065445, respectively.Fundacao para a Ciencia e Tecnologia [SFRH/BD/33176/2007]; Portuguese Government; Fundacao para a Ciencia e Tecnologia, Portugal [OBD/099758/2008]; EU; IBB/CBM

PO-0638: Adaptive dose painting by numbers for head and neck cancer: interim analysis of a randomised trial

International audience1. Recherches sur le Fayuan zayuan yuanshi ji de Sengyou (445-518), première anthologie de rites bouddhiques (suite : le contenu des juan 4 et 5) Notre travail de reconstruction du Fayuan zayuan yuanshi ji 法苑雜緣原始集 (Anthologie [pour comprendre] le commencement et l’origine de diverses [pratiques] dans le jardin des devoirs ; ci-après Fayuan) de Sengyou 僧祐 (445-518) nous a amenés cette année à nous pencher sur les 22 premiers titres de la section sur le saṃgha (Sengbao 僧寶, « Le joyau de la Loi ..

Noninvasive measurements of arterial stiffness: Repeatability and interrelationships with endothelial function and arterial morphology measures

Corey J Huck1, Ulf G Bronas1, Eric B Williamson1, Christopher C Draheim1, Daniel A Duprez2, Donald R Dengel1,31School of Kinesiology, University of Minnesota, Minneapolis, MN, USA; 2Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, MN; 3Research Service, Minneapolis Veterans Affairs Medical Center, Minneapolis, MN, USABackground: Many noninvasive arterial assessment techniques have been developed, measuring different parameters of arterial stiffness and endothelial function. However, there is little data available comparing different devices within the same subject. Therefore, the purpose of this study was to examine the repeatability and interrelationships between 3 different techniques to measure arterial stiffness and to compare this with forearm-mediated dilation.Methods: Carotid-radial pulse wave velocity was measured by the Sphygmocor (SPWV) and Complior (CPWV) devices, cardio-ankle vascular index (CAVI) was measured by the VaSera device, vascular structure and function was assessed using ultrasonography and evaluated for reliability and compared in 20 apparently healthy, college-aged men and women.Results: The intraclass correlation coefficient and standard error of the mean for the Sphygmocor (R = 0.56, SEM = 0.69), Complior (R = 0.62, SEM = 0.69), and VaSera (R = 0.60, SEM = 0.56), indicated moderate repeatability. Bland-Altman plots indicated a mean difference of 0.11 ± 0.84 for SPWV, 0.13 ± 1.15 for CPWV, and –0.43 ± 0.90 for CAVI. No significant interrelationships were found among the ultrasound measures and SPWV, CPWV, and CAVI.Conclusions: The three noninvasive modalities to study arterial stiffness reliably measures arterial stiffness however, they do not correlate with ultrasound measures of vascular function and structure in young and apparently healthy subjects.Keywords: Pulse wave velocity, intima-media thickness, flow-mediated dilatio

Analyse au microscope électronique à balayage et au rugosimètre d’impacts laser CO2 sur la dentine

The aim of the study was to compare the morphology of craters produced on the dentinal surface by CO2 laser beams (LASERSATtmCO2) before and after the removal of the carbonized layer, besides with different seetings of the power and duration of the laser beam.Thirty-three recently extracted non carious young third molar teeth were sectionned from vestibular and lingual surfaces, exposing a planed dentinal surface. Twenty impacts were made on each of dentinal surface producing 20 individual craters. The duration and the power of each laser beam were different on each tooth. The duration varied from 0.1 to 0.4 second (0.1 - 0.2 - 0.3 - 0.4 s). The power varied from 1 to 5 watts (1, 2, 3, 4, 5 w).Specimens obtained for a power of 3 and 4 watts and a duration of 0.1 and 0.2 second were examined with a JEOL 35CF (25 KV, magnification: x 30, x 110, x 200), before and after the removal of the carbonized layer. The carbonized layer of the craters was removed with an air polisher (HEATCO).Craters obtained for ail duration values as well as for ail power values were analyzed with a profilometer. The chosen profilometer was: TALISURF 10; horizontal amplification Vh = 20; vertical amplification Vv = 200.Samples were observed by a SEM and the craters depth and diameter were measured with a profilometer. Then, the carbonized layer of the craters was removed with an airpolisher and the cleaned dentinal surface was observed again with the SEM and the profilometer. Measurements were entered in a computer (using the SIPHAR programm) in order to calculate the mean values of the depth, the diameter and the area, for ail test conditions.It appears that the carbonized layer is not adherent to the dentine and can be easily removed. From the mean values, we can conclude that the diameter is about four times larger than the depth for the nocleaned craters and is about five to six times larger than the depth for the cleaned craters. The profils of the craters cannot be used for retention pins in the composite adhesion but the adhesion area is increased after a laser beam.Cette étude a pour but d’observer et de quantifier les cratères produits par un tir focalisé discontinu au laser CO2 (Lasersattm), avant et après élimination de la couche carbonisée par un aéropolisseur. Trentetrois molaires, extraites et indemnes de caries, sont coupées en deux dans le sens mésio-distal et leurs faces vestibulaires et linguales sont sectionnées pour donner une surface dentinaire plane. Vingt cratères sont réalisés par un tir focalisé discontinu sur chaque surface dentinaire. Les temps d’application et les puissances du rayonnement utilisés sont respectivement: 0.1, 0.2, 0.3, 0.4 seconde et 1, 2, 3, 4, 5 watts. Ces cratères sont analysés au microscope électronique à balayage et au rugosimètre, avant et après élimination de la couche carbonisée. Les résultats obtenus sont traités à l’aide du logiciel SIPHAR sur PC; nous obtenons un profil moyen du cratère pour chaque puissance et temps d’application utilisés. Les résultats sont les suivants: le diamètre est environ quatre fois plus grand que la profondeur avant élimination de la couche carbonisée et est cinq à six fois plus important après élimination de cette couche. Le diamètre et la profondeur des cratères sont plus importants après élimination de la couche carbonisée. La couche carbonisée a une épaisseur régulière sauf au fond du cratère où elle est plus faible que sur les parois. Avant élimination de la couche carbonisée le profil du cratère est un cône, après élimination de la couche, le profil est un cône tronqué. En conclusion, les cratères obtenus ne peuvent être considérés comme des ancrages efficaces pour d’éventuels collages dentinaires avec des composites; toutefois la surface d’adhésion s’en trouve considérablement accrue

Pulmonary function is associated with distal aortic calcium, not proximal aortic distensibility. MESA lung study

Forced expiratory volume in one second strongly predicts mortality from cardiovascular disease. FEV1 has been associated with aortic stiffness a strong independent predictor of cardiovascular mortality. However, the anatomical site and possible mechanisms linking aortic stiffness and lung function are unknown. We therefore examined if FEV1 and CT percent emphysema were associated with calcification of the abdominal aorta or reduced distensibility of the proximal thoracic aorta.The Multi-Ethnic Study of Atherosclerosis (MESA) measured aortic calcification on cardiac and abdominal CT scans and proximal aortic distensibility using magnetic resonance among participants aged 45–84 years without clinical cardiovascular disease. Spirometry was measured following ATS/ERS guidelines and percent emphysema was measured in the lung fields of cardiac CT scans. Multivariate analyses adjusted for age, sex, race/ethnicity and cardiovascular risk factors. Of 1,917 participants with aortic distensibility measures, 13% were current and 38% were former smokers. Eighteen percent had airflow limitation without asthma. FEV1 was associated with the extent of distal aortic calcification (0.76; 95%CI 0.60–0.97, p = 0.02) but not proximal aortic calcification or proximal aortic distensibility (−0.04 mmHg−1; 95%CI −0.16–0.09 mmHg−1, p = 0.60). Percent emphysema was associated with neither measure. FEV1 was associated with severity of distal aortic calcification where it was present independently of smoking and other cardiovascular risk factors but not with distensibility or calcification of the proximal aorta

The development and psychometric validation of the self-efficacy and performance in self-management support (SEPSS) Instrument

__Aim:__ To develop and psychometrically test the self-efficacy and performance in self-management support (SEPSS) instrument. __Background:__ Facilitating persons with a chronic condition to take an active role in the management of their condition, implicates that nurses acquire new competencies. An instrument that can validly and reliably measure nurses' performance and their perceived capacity to perform self-management support is needed to evaluate current practice and training in self-management support. __Design:__ Instrument development and psychometric testing of the content and construct validity, factor structure and reliability. __Methods:__ A literature review and expert consultation (N = 17) identified the content. The items were structured according to the Five-A's model and an overarching category of 'overall' competencies. The initial instrument was tested in a sample of 472 nurses and 51 nursing students from Belgium and the Netherlands, between June 2014-January 2015. __Results:__ Confirmatory factor analyses revealed satisfactory fit indices for the six-factor structure. Discriminating power was demonstrated for subgroups. The overall internal consistency (Cronbach's alpha) was high both for the self-efficacy and the performance items. The test-retest intra-class correlation coefficients were good. __Conclusion:__ The SEPSS instrument is a 36-item, Likert-scaled self-reporting instrument with good content and construct validity, and good internal consistency reliability and good test-retest reliability. Therefore, it is a promising instrument to measure self-efficacy and performance with regard to self-management support

Effects of High Flavanol Dark Chocolate on Cardiovascular Function and Platelet Aggregation.

Regular consumption of chocolate and cocoa products has been linked to reduced cardiovascular mortality. This study compared the effects of high flavanol dark chocolate (HFDC; 1064mg flavanols/day for 6 weeks) and low flavanol dark chocolate (LFDC; 88mg flavanols/day for 6 weeks) on blood pressure, heart rate, vascular function and platelet aggregation in men with pre-hypertension or mild hypertension. Vascular function was assessed by pulse wave analysis using radial artery applanation tonometry in combination with inhaled salbutamol (0.4 mg) to assess changes due to endothelium-dependent vasodilatation. HFDC did not significantly reduce blood pressure compared to baseline or LFDC. Heart rate was increased by LFDC compared to baseline, but not by HFDC. Vascular responses to salbutamol tended to be greater after HFDC. Platelet aggregation induced by collagen or the thromboxane analogue U46619 was unchanged after LFDC or HFDC, whereas both chocolates reduced responses to ADP and the thrombin receptor activator peptide, SFLLRNamide (TRAP6), relative to baseline. Pre-incubation of platelets with theobromine also attenuated platelet aggregation induced by ADP or TRAP6. We conclude that consumption of HFDC confers modest improvements in cardiovascular function. Platelet aggregation is modulated by a flavanol-independent mechanism that is likely due to theobromine.This study was supported by a grant (to R. Corder) from Barry Callebaut Belgium N

Spectroscopy of a single-carrier bilayer graphene quantum dot from time-resolved charge detection

We measured the spectrum of a single-carrier bilayer graphene quantum dot as a function of both parallel and perpendicular magnetic fields, using a time-resolved charge detection technique that gives access to individual tunnel events. Thanks to our unprecedented energy resolution of 4$\mu~$eV, we could distinguish all four levels of the dot's first orbital, in particular in the range of magnetic fields where the first and second excited states cross ($B_\perp\lesssim 100~$mT). We thereby experimentally establish, the hitherto extrapolated, single-charge carrier spectrum picture and provide a new upper bound for the inter-valley mixing, equal to our energy resolution