100 research outputs found
Preliminary Studies of the Effects of Nanoconsolidants on Mural Paint Layers with a Lack of Cohesion
This paper reports the preliminary results of a comparative analysis of the effects of three consolidants on the color appearance of fresco paint layers affected by lack of cohesion. In vitro assays were performed with a laboratory-synthesized nanolime, a commercial nanolime (CaLoSiL® IP25), and a commercial acrylic resin (PrimalTM SF-016 ER®) applied by nebulization over two sets of replicas of buon and lime fresco painted with red and yellow ochres and smalt pigments. The paint layers were surveyed before, one week, and one month after treatment with technical photography in the visible range (Vis) and ultraviolet-induced fluorescence in the visible range (UVF), as well as optical microscopy (OM-Vis), colorimetry, spectrophotometry, and scanning electron microscopy coupled with energy dispersive x-ray spectroscopy (SEM-EDS). Experimental work also comprised the synthesis of nanolime and its characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetry analysis (TGA-DTG). The results show no alteration on pigments’ spectral curves and elemental composition. The increase in the CIEL* coordinate and ∆E color variation noticed after the treatment with the nanolimes is associated with a white haze formation on the paint surfaces. The impact on color appearance is higher on the darker tones.Fundação para a Ciência e a Technologia FCT, Portugal (the Portuguese national funding agency for science, research and technology): UIDB/04449/2020; UIDP/04449/2020; DL 57/2016/CP1372/CT0013; DL/57/2016/CP1338. EMJMD ARCHMAT, co-founded by Erasmus+ program under GA N. 2018-1468/001-00
Cerebral Venous Sinus Thrombosis - Diagnostic Strategies and Prognostic Models: A Review
In 1825, Ribes described a case of a 45-year old man who died after a 6-month history of epilepsy, seizures and delirium. The autopsy examination revealed thrombosis of the superior sagittal sinus, the left lateral sinus and a cortical vein in the parietal region. This was probably the first detailed description of extensive cerebral venous sinus thrombosis (CVST). Since then, the literature describing this disease has comprised of case reports, series and some newer prospective studies, including recent reviews and guidelines (statement) on the diagnosis and management of CVST (Siddiqui \u26 Kamal, 2006; Stam, 2005; Saposnik et al, 2011; Brown \u26 Thore, 2011).
The cerebral venous sinus thrombosis is a challenging condition and it is most common than previously thought. CVST accounts for 0.5% to 1.0% of all strokes and usually affects young individuals. Important advances have been made in the understanding of the pathophysiology of this vascular disorder. The diagnosis of CVST is still frequently overlooked or delayed as a result of the wide spectrum of clinical symptoms and the often sub-acute or lingering onset. Patients with CVST commonly present with headache, although some develop a focal neurological deficit, decreased level of consciousness, seizures, or intracranial hypertension without focal neurological signs. Uncommonly, an insidious onset may create a diagnostic challenge. The main problem of this disorder is that it is very often unrecognised at initial presentation. In particular, a prothrombotic factor or a direct cause is identified in approximately 66% of the CVST patients (a list of most important causal and risk factors are listed in Table 1).
Cerebral venous thrombosis is more common in women than men, with a female to male ratio of 3:1 (cited in Ferro \u26 Canhao, 2011). The imbalance may be due to the increased risk of CVST associated with pregnancy and puerperium and with oral contraceptives. The female predominance in CVST is found in young adults, but not in children or older adults
Estudos preliminares para consolidação de suportes com pintura mural: síntese e caracterização de nanocais
-Resumo
Neste trabalho apresentam-se os resultados da síntese e da caracterização de nano-materiais de
hidróxido de cálcio e de hidróxido de magnésio visando a sua aplicação como consolidantes de
suportes com pintura mural. Este estudo preliminar constitui a etapa inicial de um projeto em
curso e que tem como principal objetivo o desenvolvimento de novas estratégias de síntese de
nano-materiais inovadores para conservação e restauro de revestimentos antigos.
- Abstract
In this publication, we report the synthesis and characterization of calcium and magnesium
hydroxides nanoparticles for consolidation of mural paintings. Some preliminary results are
discussed. This research is the initial part of our ongoing project which aims to develop new
synthetic strategies towards novel and innovative materials for preservation and restoration of old
rend
Metabolic syndrome severity score: range and associations with cardiovascular risk factors
Introduction: Metabolic Syndrome Severity Score (MSSS) is a new clinical prediction rule (CPR) for diagnostic and therapeutic decisions and employs available components (sex, age, race, systolic blood pressure, waistline circumference, high-density lipoprotein, triglycerides and fasting blood glucose). The aim of our work was to perform cross-sectional pilot trial on middle-aged healthy volunteers and patients with metabolic syndrome (MetS) with and without type 2 diabetes mellitus (T2DM) for studying feasibility and implementation of MSSS and its associations with cardiovascular risk factors.Material and methods: We approached 64 eligible participants from Bulgaria. The MSSS values, together with demographic, anthropometric, medical history, laboratory findings, CVD risk factors, QRISK2 score for 10-year cardiovascular risk and predicted heart age, were analysed. Descriptive statistics with tests for comparison (e.g., t-test, c2) between groups as well as ANOVA and logistic regression were applied. Results: We analysed data from 56 participants (aged 50.11 ±3.43 years). The MSSS was higher in MetS patients (including 6 T2DM patients) than in controls (n = 29; 51.8%) presented as percentiles (69.97% and 34.41%, respectively) and z-scores (0.60 and –0.45, respectively) (p < 0.05). The logistic regression model of MSSS indicated a positive association with MetS/T2DM cases (correctness > 85%, p < 0.01). For further validation purposes, positive correlations of MSSS with CVDrisk factor as diastolic blood pressure (Rho = 0.399; p < 0.003) and QRISK2 score (Rho = 0.524; p < 0.001) or predicted heart age (Rho = 0.368; p < 0.007) were also found.Conclusions: The pilot study of MSSS in Bulgaria indicated feasibility and consistency of its implementation among patients with metabolic syndrome and/or T2DM and healthy volunteers
Bis(tetramethylamonium) bis(2,4,5-carboxybenzoate)–benzene-1,2,4,5-tetracarboxylic acid (1/1)
The asymmetric unit of the title compound, 2C4H12N+·2C10H5O8
−·C10H6O8, consists of a tetramethylamonium cation, an anion derived from the singly deprotonated pyromellitic acid anion, 2,4,5-carboxybenzoate (H3bta−), and one-half of a benzene-1,2,4,5-tetracarboxylic acid (H4bta) molecule, which has the centroid of the aromatic ring positioned at a crystallographic centre of inversion. The H4bta and H3bta− residues are involved in an extensive intermolecular O—H⋯O hydrogen-bonding network, which leads to a three-dimensional supramolecular structure containing one-dimensional channels running parallel to the [001] crystallographic direction. These channels house the tetramethylamonium cations
Synthesis, characterisation and luminescent properties of lanthanide-organic polymers with picolinic and glutaric acids
Three new lanthanide(III) complexes (Ln = Sm, Tb and Eu)
of picolinic and glutaric acid were prepared and characterised.
The crystal structure of the complex [Sm(glu)(pic)-
(H2O)2] (where Hpic and H2glu stand for picolinic and glutaric
acid, respectively) was determined by single-crystal Xray
diffraction. All the Ln complexes were characterised by
elemental analysis, infrared spectroscopy, X-ray powder diffraction
and thermoanalytical measurements. The combined
Introduction
The design of functional units from the molecular scale
to macroscopic assemblies has emerged as a new paradigm
in materials synthesis resulting in an interplay between conventional
molecular chemistry and conventional solid-state
science. This has been particularly clear in the development
of functional materials using coordination compounds such
as in the field of semiconductors technology, supramolecular
machinery, microporous and hybrid materials and catalysis.[
1] In some cases, the development of these functional
materials is based on the chemistry of well-known coordination
compounds as illustrated by the assembly of inorganic-
organic extended lattices[2] and in the thermolysis of
metal thiolato compounds to produce thin films or nanoparticles.[
3]
Metals coordinated to aromatic ambidentate ligands
form a class of compounds with a wide variety of coordination
modes which has long attracted the attention of chemists.[
4] Griffith and co-workers extended this type of chemistry
to the second row transition metals and, in particular,
[a] Department of Chemistry, University of Aveiro, CICECO,
3810-193 Aveiro, Portugal
Fax: +351-234-370-084
E-mail: [email protected]
[b] Department of Physics, University of Aveiro, CICECO,
3810-193 Aveiro, Portugal
[c] Department of Chemistry, University of Cambridge,
Lensfield Road, CB2 1EW Cambridge, United Kingdom
Supporting information for this article is available on the
WWW under http://www.eurjic.org or from the author.
© 2007 Wiley-VCH Verlag 4238 GmbH & Co. KGaA, Weinheim Eur. J. Inorg. Chem. 2007, 4238–4246
data show that these Ln complexes are isostructural. The effect
of both organic ligands on the photoluminescent behaviour
of the Sm3+, Eu3+ and Tb3+ complexes is discussed and
we anticipate the possibility of controlling the photoluminescence
of picolinic-containing lanthanide compounds by systematically
varying the length of the bridging ligand.FCT - POCI/QUI/58377/2004Grant - SFRH/BD/17968/2004Grant - SFRH/BPD/14954/ 200
Oxygen adsorption on the Ru (10 bar 1 0) surface: Anomalous coverage dependence
Oxygen adsorption onto Ru (10 bar 1 0) results in the formation of two
ordered overlayers, i.e. a c(2 times 4)-2O and a (2 times 1)pg-2O phase, which
were analyzed by low-energy electron diffraction (LEED) and density functional
theory (DFT) calculation. In addition, the vibrational properties of these
overlayers were studied by high-resolution electron loss spectroscopy. In both
phases, oxygen occupies the threefold coordinated hcp site along the densely
packed rows on an otherwise unreconstructed surface, i.e. the O atoms are
attached to two atoms in the first Ru layer Ru(1) and to one Ru atom in the
second layer Ru(2), forming zigzag chains along the troughs. While in the
low-coverage c(2 times 4)-O phase, the bond lengths of O to Ru(1) and Ru(2) are
2.08 A and 2.03 A, respectively, corresponding bond lengths in the
high-coverage (2 times 1)-2O phase are 2.01 A and 2.04 A (LEED). Although the
adsorption energy decreases by 220 meV with O coverage (DFT calculations), we
observe experimentally a shortening of the Ru(1)-O bond length with O coverage.
This effect could not be reconciled with the present DFT-GGA calculations. The
nu(Ru-O) stretch mode is found at 67 meV [c(2 times 4)-2O] and 64 meV [(2 times
1)pg-2O].Comment: 10 pages, figures are available as hardcopies on request by mailing
[email protected], submitted to Phys. Rev. B (8. Aug. 97), other related
publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm
R-Allyl Nickel(II) Complexes with Chelating N-Heterocyclic Carbenes: Synthesis, Structural Characterization, and Catalytic Activity
The N-heterocyclic carbene (NHC) nickel complexes [(L)Ni(NHC)][BArF4] (ArF = 3,5-bis(trifluoromethyl)-
phenyl; L = allyl (1), methylallyl (2); NHC = 1-(2-picolyl)-3-methylimidazol-2-ylidene (a), 1-(2-picolyl)-3-isopropylimidazol-2-ylidene (b), 1-(2-picolyl)-3-n-butylimidazol-2-ylidene (c), 1-(2-picolyl)-3-phenylimidazol-2-ylidene (d), 1-(2-picolyl)-3- methylbenzoimidazol-2-ylidene (e), 1-(2-picolyl)-4,5-dichloro-3-methylimidazol-2-ylidene (f)) have been obtained in high yields and characterized by NMR spectroscopy. Furthermore, 1d was unambiguously characterized by single-crystal X-ray crystallography. Complexes 1a−f/2a−f have shown catalytic activity toward dimerization and hydrosilylation of styrenes. In particular, 1a proved to be the most efficient catalyst in the dimerization of styrene derivatives in the absence of cocatalyst. Also, complexes 1a,d showed high selectivity and moderate to good yields in hydrosilylation reactions
Effect of Systemic Hypertension With Versus Without Left Ventricular Hypertrophy on the Progression of Atrial Fibrillation (from the Euro Heart Survey).
Hypertension is a risk factor for both progression of atrial fibrillation (AF) and development of AF-related complications, that is major adverse cardiac and cerebrovascular events (MACCE). It is unknown whether left ventricular hypertrophy (LVH) as a consequence of hypertension is also a risk factor for both these end points. We aimed to assess this in low-risk AF patients, also assessing gender-related differences. We included 799 patients from the Euro Heart Survey with nonvalvular AF and a baseline echocardiogram. Patients with and without hypertension were included. End points after 1 year were occurrence of AF progression, that is paroxysmal AF becoming persistent and/or permanent AF, and MACCE. Echocardiographic LVH was present in 33% of 379 hypertensive patients. AF progression after 1 year occurred in 10.2% of 373 patients with rhythm follow-up. In hypertensive patients with LVH, AF progression occurred more frequently as compared with hypertensive patients without LVH (23.3% vs 8.8%, p = 0.011). In hypertensive AF patients, LVH was the most important multivariably adjusted determinant of AF progression on multivariable logistic regression (odds ratio 4.84, 95% confidence interval 1.70 to 13.78, p = 0.003). This effect was only seen in male patients (27.5% vs 5.8%, p = 0.002), while in female hypertensive patients, no differences were found in AF progression rates regarding the presence or absence of LVH (15.2% vs 15.0%, p = 0.999). No differences were seen in MACCE for hypertensive patients with and without LVH. In conclusion, in men with hypertension, LVH is associated with AF progression. This association seems to be absent in hypertensive women
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