Two new urea-bipyridine derived bridged organosilanes (P5 and P6) have been synthesized and their hydrolysis–condensation under nucleophilic catalysis in the presence of Eu3+ salts led to luminescent ...bridged silsesquioxanes (M5-Eu and M6-Eu). An important loading of Eu3+ (up to 11%w) can be obtained for the material based on the 6,6′-isomer. Indeed the photoluminescence properties of these materials, that have been investigated in depth (photoluminescence (PL), quantum yield, lifetimes), show a significantly different complexation mode of the Eu3+ ions for M6-Eu, compared with M4-Eu (obtained from the already-reported 4,4′-isomer) and M5-Eu. Moreover, M6-Eu exhibits the highest absolute emission quantum yield value (0.18 ± 0.02) among these three materials. The modification of the sol composition upon the addition of a malonamide derivative led to similar luminescent features but with an increased quantum yield (0.26 ± 0.03). In addition, M6-Eu can be processed as thin films by spin-coating on glass substrates, leading to plates coated by a thin layer (∼54 nm) of Eu3+-containing hybrid silica exhibiting one of the highest emission quantum yields reported so far for films of Eu3+-containing hybrids (0.34 ± 0.03) and an interesting potential as new luminescent solar concentrators (LSCs) with an optical conversion efficiency of ∼4%. The ratio between the light guided to the film edges and the one emitted by the surface of the film was quantified through the mapping of the intensity of the red pixels (in the RGB color model) from a film image. This quantification enabled a more accurate estimation of the transport losses due to the scattering of the emitted light in the film (0.40), thereby correcting the initial optical conversion efficiency to a value of 1.7%.
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CO oxidation over Pd(100) and Pd75Ag25(100) has been investigated by a combination of near-ambient-pressure X-ray photoelectron spectroscopy, quadrupole mass spectrometry, density functional theory ...calculations, and microkinetic modeling. For both surfaces, hysteresis is observed in the CO2 formation during the heating and cooling cycles. Whereas normal hysteresis with light-off temperature higher than extinction temperature is present for Pd(100), reversed hysteresis is observed for Pd75Ag25(100). The reversed hysteresis can be explained by dynamic changes in the surface composition. At the beginning of the heating ramp, the surface is rich in palladium, which gives a CO coverage that poisons the surface until the desorption rate becomes sufficiently high. The thermodynamic preference for an Ag-rich surface in the absence of adsorbates promotes diffusion of Ag from the bulk to the surface as CO desorbs. During the cooling ramp, an appreciable surface coverage is reached at temperatures too low for efficient diffusion of Ag back into the bulk. The high concentration of Ag in the surface leads to a high extinction temperature and, consequently, the reversed hysteresis.
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To describe microvascular changes in the maculas of individuals with type 2 diabetes observed on optical coherence tomography angiography (OCTA) images. We compared the maculas of diabetic subjects ...without diabetic retinopathy with those of healthy subjects and correlated the findings with the clinical profiles of diabetic subjects.
One eye each of 30 patients with diabetes and 30 healthy individuals were examined. The patients with diabetes underwent funduscopy, retinography, and fluorescein angiography to rule out retinopathy. All subjects underwent optical coherence tomography angiography of a macular area (6×6 mm2), and the foveal and parafoveal vascular densities were analyzed in the superficial and deep retinal vascular plexus. The foveal and parafoveal thicknesses, foveal avascular zone of the superficial plexus, and choriocapillaris flow area were also examined. The optical coherence tomography angiography results were compared between the two study groups and correlated with the following parameters: visual acuity, time since diabetes diagnosis, glycemic control, lipid profile, and renal function of patients with diabetes.
A minimal increase in the choriocapillaris flow area was observed in the patients with diabetes (mean area, 22.3 ± 4.6 mm2 in controls; 22.6 ± 3.9 mm2 in patients with diabetes) (p=0.017). No significant differences were observed between other optical coherence tomography angiography parameters analyzed in the two groups. Glycosylated hemoglobin and fasting blood glucose levels were significantly negatively correlated with the foveal vascular density of both plexuses; conversely, fasting blood glucose levels were positively correlated with the choriocapillaris flow area (p=0.034). The other clinical parameters were not correlated with the optical coherence tomography angiography findings.
Optical coherence tomography angiography may not be the most appropriate tool for detecting preclinical changes in patients with diabetes, moreover, optical coherence tomography angiography; does not replace clinical examinations. Glycemic control should be the primary clinical parameter considered during retinopathy screening. Larger studies are necessary to confirm these findings.
The applicably of multi-objective optimization to ellipsometric data analysis is presented and a method to handle complex ellipsometric problems such as multi sample or multi angle analysis using ...multi-objective optimization is described. The performance of a multi-objective genetic algorithm (MOGA) is tested against a single objective common genetic algorithm (CGA). The procedure is applied to the characterization (refractive index and thickness) of planar waveguides intended for the production of optical components prepared sol-gel derived organic-inorganic hybrids, so-called di-ureasils, modified with zirconium tetrapropoxide, Zr(OPr(n))(4) deposited on silica on silicon substrates. The results show that for the same initial conditions, MOGA performs better than the CGA, showing a higher success rate in the task of finding the best final solution.
To evaluate vascular density in super-ficial and deep capillary plexuses of the retina, measured using optical coherence tomography angiography in patients with branch retinal vein occlusion. ...Affected eyes were compared with the contralateral eye of the same patient and both were compared with normal eyes.
A cross-sectional study including 16 previously untreated patients with branch retinal vein occlusion. Patients with poor quality examinations, bilateral disease, high refractive error, or any other retinal or choroidal disease were excluded. A total of 31 patients without eye disease were also selected as a comparison group. All participants underwent five optical coherence tomography angiographies, and only those with at least two good quality examinations were selected. The Kruskal-Wallis, Wilcoxon signed-rank, and Mann-Whitney U tests were used for the statistical analysis.
Vascular density was lower in affected eyes compared with contralateral eyes: whole density (p=0.020 for capillary plexuses superficial; p=0.049 for deep capillary plexuses) and parafoveal density (p=0.020 for capillary plexuses superficial; p=0.011 for deep capillary plexuses). Vascular density was also lower in affected eyes compared with normal eyes: whole density (p<0.001 for capillary plexuses superficial and deep) and parafoveal density (p<0.001 for capillary plexuses superficial and deep). Whole density (p=0.001 for capillary plexuses superficial and deep) and parafoveal density (p=0.001 for capillary plexuses superficial; p<0.001 for deep capillary plexuses) were both lower in the contralateral eyes compared with normal eyes. Following adjustment for arterial hypertension, this difference was no longer observed.
Vascular density in capillary plexuses and deep capillary plexuses was lower in the eyes affected by branch retinal vein occlusion. Furthermore, the lower vascular density noted in the contralateral eyes indicates that changes most likely occurred in these eyes prior to the appearance of any clinically detectable alterations, reflecting the early signs of hypertensive retinopathy.
Abstract
BACKGROUND AND AIMS
Peritoneal dialysis (PD) patients are frequently exposed to contrast media through contrast-enhanced computed tomography (CT) and/or coronary angiography, which may be ...used as diagnostic tools or as part of pretransplant evaluation. However, the risk of contrast nephropathy frequently limits the use of these imaging techniques. The authors aim to evaluate the loss of kidney function after contrasted examination in PD patients.
METHOD
We performed an observational retrospective study in a population of patients with end-stage kidney disease on PD. All patients included had performed an ionized radiation-imaging exam (CT or coronary angiography), with or without contrast media. In patients who performed more than one of the aforementioned exams, only the first one was considered. Demographic and laboratory data including kidney function and dialysis dose before and after the imaging exams were collected. We divided the population into two groups (no contrast use versus contrast use) and compared them using Mann–Whitney test or Chi square. A survival analysis was performed (time to exam; outcome—loss of renal function; predictor—contrast use).
RESULTS
A population of 41 patients in PD, 26 in automated PD (63.4%), with a dialysis vintage of 29 (17–38) months were included in this analysis. The median time since starting PD and the exam was 15 (5–20) months, and contrast was used in 21 exams (51.2%). Five patients underwent coronary angiography and 16 were submitted to contrast-enhanced CT. Only two patients performed contrast nephropathy prophylaxis before contrast exposure.
In univariate analysis, we found no difference between renal residual function, KT/v and creatinine clearance before and after the imaging exam, irrespective of contrast use. After the diagnostic exam, 19 patients lost residual renal function median GFR 1 (1–2) mL/min/1.73 m2, and the group of patients who did not use contrast were the most affected ones; however, there was no statistical significance difference between the two groups (P = 0.08). Since we found a significant difference in the time to imaging exam between the two studied groups, we performed a survival analysis, and the use of contrast was associated with preservation of renal function (P = 0.02). A multivariate Cox analysis with age, Charlson index, GFRe pre-exam, diabetes, use of RAASi, beta-blocker, loop diuretic and spironolactone as potential confounders showed that use of contrast was not associated with loss of renal function in PD patients.
CONCLUSION
Our study showed that contrast nephropathy is not frequent in PD patients and that we can allow contrast media (low or iso-osmolal) as it was not associated with loss of residual renal function.
The application of spectroscopic ellipsometry for the characterization of UV-patterned channel waveguides to obtain the refractive index contrast and surface deformation profile is presented. Thin ...films were prepared with organic-inorganic di-ureasils hybrids modified with zirconium tetra-propoxide deposited in silica on silicon substrates. The channel waveguides were produced by direct writing using UV laser radiation. The refractive index contrast and the surface ablation induced by the UV optical signal were estimated by ellipsometry being 4.5 × 10 -3 and 30.5 nm, respectively. The deepness of the surface ablation due to the UV exposition was also estimated by atomic force microscopy measurements that pointed out a value of 31.0 ± 1.0 nm, concordant with the ellipsometric calculations. The near-field intensity technique was used as a support for contextualizing the proposed ellipsometry method for the characterization of refractive index profiles. The estimated refractive index contrast (2.0 × 10 -3 ) is in a good agreement with the refractive index contrast derived from ellipsometry.
A presente dissertação "Requalificação de um território no Douro: Reflexão de uma proposta desenvolvida em estágio" surge da vontade de expor um caso prático desenvolvido em ambiente de estágio, no ...atelier Barbosa & Guimarães. O estágio curricular configura uma experiência crucial no desenvolvimento intelectual de um futuro arquiteto que, de forma modesta, simboliza o primeiro contacto com o percurso profissional. Esta é uma transição que fortalece o carácter pessoal, passando de uma prática académica e mais conceptual para prática real, onde a formação adquirida ajuda a superar os desafios propostos.
Desta forma, o tema desta dissertação alicerça-se numa reflexão sobre esta experiência de estágio, bem como, numa investigação sobre os processos e métodos de desenvolvimento de um projeto de arquitetura. Reflete-se acerca do contexto, da circunstância e do programa, em que o caso prático, Blend in Douro, se encontra inserido, sendo a região do Douro o cenário. A monocultura da vinha e a crescente transformação do território duriense tem conduzido ao desaparecimento de certos valores e posto em causa a identidade coletiva do lugar, no qual determinou a premissa do projeto.
Assim, o caso prático da autoria do atelier Barbosa & Guimarães, pretende requalificar um espaço descaracterizado na paisagem duriense, perto da cidade do Peso da Régua. A proposta visa transformar esse espaço desvirtuado num empreendimento turístico que respeite e preserve o património material e imaterial da região, uma estratégia em que a arquitetura está determinada em encontrar uma identidade que movimente um balanço entre o passado e o presente. Salienta-se ainda que esta intervenção considera a qualificação de paisagem cultural atribuída pela UNESCO em 2001.
Relativamente ao processo de envolvimento no caso prático, explorou-se e refletiu-se num conjunto de questões, nomeadamente, sobre as várias identidades, sistemas e dinâmicas presentes no território, sejam elas arquitetónicas, urbanísticas, culturais económicas ou sociais. Neste sentido, o trabalho procura analisar, (re)conhecer e (re)interpetar alguns pontos críticos do projeto, com o objetivo de enquadrar, da melhor forma possível o objeto na paisagem.
Por fim, a dissertação trata-se de um exercício de carácter prático, que procura através da teoria, gerar um discurso arquitetónico.
The present dissertation, "Requalification of a territory in the Douro: Reflection of a project developed in an internship" arises from the desire to expose a project developed during an internship at the Barbosa & Guimarães studio. The curricular internship is a necessary experience in the intellectual development of a future architect that, modestly, symbolizes the first interaction with the professional career. A transition that strengthens the personal character, moving from an academic and conceptual practice to a real practice, where the formation acquired helps to overcome the proposed challenges.
In this way, the theme of this dissertation is based on reflecting on this internship experience and investigating the processes and methods of developing an architecture project. Furthermore, it intends to reflect on the context, circumstances, and program in which the practical case, Blend in Douro, is inserted, where the Douro region is the scenario. The monoculture of wine and the transformation of this territory have led to the disappearance of certain values and reached into question the collective identity of the place, which determined the idea of the project.
Thus, the practical case by the studio Barbosa & Guimarães intends to requalify a de-characterized space in the Douro landscape, close to the city of Peso da Régua. The proposal aims to transform this distorted space into a tourist development that respects and preserves the material and immaterial heritage of the region, a strategy in which architecture is determined to find an identity that moves a balance between the past and the present. It should be relevant that this intervention regards the qualification of cultural landscape awarded by UNESCO in 2001.
About the process that involves the practical case, a set of questions was explored and reflected on, namely, the diverse identities, systems, and dynamics present in the territory, be they architectural, urban, cultural, economic, or social. In this sense, the work aims to analyze, (re)know, and (re)interpret some critical points of the project, with the intent of structuring the project in the landscape in the best possible way.
Finally, the dissertation is a practical exercise that seeks, through theory, to generate an architectural discourse.
Fluid status is crucial for dialysis patients. Volume overload is a major cardiovascular risk factor. Nevertheless, volume depletion is associated with myocardial stunning and cerebral ischaemia. For ...decades, many diagnostic tools have been proposed for increased accuracy in evaluation of volemia, considering that clinical assessment is unreliable. Lung ultrasound and bioimpedance analysis emerged as the most useful tools, although randomized clinical studies are lacking to implement their universal use. Early management of hydration may improve clinical outcomes, as it allows personalized dialysis prescriptions and nutritional support.
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