Sol-Gel Synthesis of Fine Gd2CuO4 Particles: Influence of Synthesis Variables

Fine particles of Gd₂CuO₄ were prepared by a sol-gel reaction of an aqueous solution of metal nitrates in the presence of urea, which leads to high-homogeneity polycrystalline powders of Gd₂CuO₄. We have studied the synthesis conditions, demonstrating the existence of a relationship between the calcination temperature and the heating time needed to attain the pure phase. Gd₂CuO₄ was obtained at temperatures of the order of 650°C, lower than temperatures employed in the conventional ceramic technique. The influence of the [urea]/[salts] ratio and an excess of Cu(II) in the starting solution was also studied and discussed. X-ray powder diffraction, inductively coupled plasma atomic emission spectroscopy (ICPAES), photon correlation spectroscopy (PCS), and transmission electron microscopy (TEM) were used to characterize the Gd₂CuO₄ samples obtained.     

Use of Photodynamic Therapy Associated with Antimicrobial Peptides for Bacterial Control: A Systematic Review and Meta-Analysis

Considering the challenges related to antimicrobial resistance, other strategies for controlling infections have been suggested, such as antimicrobial photodynamic therapy (aPDT) and antimicrobial peptides (AMP). This study aims to perform a systematic review and meta-analysis to obtain evidence on the antimicrobial effectiveness of aPDT associated with AMP and establish in vitro knowledge on this topic for further study designs. The PubMed, Scopus, Web of Science, Science Direct, Scielo, and Cochrane Library databases were searched. Two independent and calibrated researchers (Kappa = 0.88) performed all the systematic steps according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The odds ratio (OR) was used as the effect measure. The Peto method was used to perform the meta-analysis due to the sparse data. Twenty studies were included in the present review. The result was significant (OR = 0.14/p = 0.0235/I-squared = 0%), showing better outcomes of aPDT associated with peptides than those of aPDT alone for controlling the microbial load. Only 20% of the studies included evaluated this approach in a biofilm culture. Combined treatment with aPDT and AMP highly increased the ability of microbial reduction of Gram-positive and Gram-negative bacteria. However, additional blind studies are required to evaluate the efficacy of this therapy on microbial biofilms.     

Acid Sphingomyelinase Deficiency: A Clinical and Immunological Perspective

Acid sphingomyelinase deficiency (ASMD) is a lysosomal storage disease caused by deficient activity of acid sphingomyelinase (ASM) enzyme, leading to the accumulation of varying degrees of sphingomyelin. Lipid storage leads to foam cell infiltration in tissues, and clinical features including hepatosplenomegaly, pulmonary insufficiency and in some cases central nervous system involvement. ASM enzyme replacement therapy is currently in clinical trial being the first treatment addressing the underlying pathology of the disease. Therefore, presently, it is critical to better comprehend ASMD to improve its diagnose and monitoring. Lung disease, including recurrent pulmonary infections, are common in ASMD patients. Along with lung disease, several immune system alterations have been described both in patients and in ASMD animal models, thus highlighting the role of ASM enzyme in the immune system. In this review, we summarized the pivotal roles of ASM in several immune system cells namely on macrophages, Natural Killer (NK) cells, NKT cells, B cells and T cells. In addition, an overview of diagnose, monitoring and treatment of ASMD is provided highlighting the new enzyme replacement therapy available.     

The strategic siting and the roofing area requirements of building-integrated photovoltaic solar energy generators in urban areas in Brazil

Building-integrated photovoltaic (BIPV) generators are typically small and distributed solar power plants that occupy virtually no space because they are part of the building envelope, and they generate power at point of use. A more widespread use of grid-connected photovoltaics (PV) is hindered by a number of reasons which include the declining, but still high costs of the photogenerated kilowatt hour, and the lack of knowledge about the benefits of distributed generation with PV in the urban environment. When strategically sited, PV generators integrated to building façades and rooftops in urban areas at limited penetration levels can benefit local feeders with these distributed “negative loads”. A number of studies have been published, with learning curves demonstrating the cost-reduction potential of large-scale PV production, and in some markets the cost of PV electricity is approaching residential tariffs, the so-called grid parity. Due to the intermittent nature of the solar radiation resource, PV is considered non-despatchable power, but under some conditions, in sunny urban areas with electricity load curves dominated by air-conditioning loads, there is a high correlation between PV generation and feeder loads. In these situations, a considerable fraction of a given PV generator can be considered despatchable power. In this work we assess the potential of building-integrated, grid-connected PV generation in the state capital Florianópolis, in South Brazil. The deployment of six different commercially available PV technologies is compared with total roof area availability, solar generation profiles, and local feeder load curves for a selected number of urban areas in the city. Our results demonstrate the advantages of strategically siting PV generators in the urban environment.     

Smectite quantification in sediments and soils by thermogravimetric analyses

A new method is assayed, consisting in measuring the weight loss between 100 and 450 °C of samples solvated with ethylene glycol and previously saturated in Mg. This approach allows an approximation to be made of the dioctahedral Al-rich smectite content in samples. The proportion of expandable material in the sample is calculated according to the following equation, obtained from artificial mixtures prepared with variable proportions of smectite: y = 3.96x − 4.05 (R² = 0.96), where x is the percentage of loss and y is the percentage of smectite in the sample. The slope of the equation agrees perfectly with the theoretical proportion of ethylene glycol in a solvated smectite, around 25%, and with the equivalent values determined on natural standards. In addition, the ordinate of the origin is also in agreement with the values of around 1% obtained in smectite-free samples. The method proposed is low-cost and easy to apply as a complement to X-ray diffraction determinations of expandable clay content in sediments and soils with the potential for landslides in civil engineering.     

Monte Carlo electron-trajectory simulations in bright-field and dark-field STEM: Implications for tomography of thick biological sections

A Monte Carlo electron-trajectory calculation has been implemented to assess the optimal detector configuration for scanning transmission electron microscopy (STEM) tomography of thick biological sections. By modeling specimens containing 2 and 3 at% osmium in a carbon matrix, it was found that for 1-μm-thick samples the bright-field (BF) and annular dark-field (ADF) signals give similar contrast and signal-to-noise ratio provided the ADF inner angle and BF outer angle are chosen optimally. Spatial resolution in STEM imaging of thick sections is compromised by multiple elastic scattering which results in a spread of scattering angles and thus a spread in lateral distances of the electrons leaving the bottom surface. However, the simulations reveal that a large fraction of these multiply scattered electrons are excluded from the BF detector, which results in higher spatial resolution in BF than in high-angle ADF images for objects situated towards the bottom of the sample. The calculations imply that STEM electron tomography of thick sections should be performed using a BF rather than an ADF detector. This advantage was verified by recording simultaneous BF and high-angle ADF STEM tomographic tilt series from a stained 600-nm-thick section of C. elegans. It was found that loss of spatial resolution occurred markedly at the bottom surface of the specimen in the ADF STEM but significantly less in the BF STEM tomographic reconstruction. Our results indicate that it might be feasible to use BF STEM tomography to determine the 3D structure of whole eukaryotic microorganisms prepared by freeze-substitution, embedding, and sectioning.     

PS/EPDM blends prepared by in situ polymerization of styrene

PS/EPDM blends formed by in situ polymerization of styrene in the presence of EPDM were prepared. EPDM has excellent resistance to factors such as weather, ozone and oxidation and it could be a good alternative for substituting polybutadiene‐based rubbers in PS toughening. The PS/EPDM blends present two phases, an EPDM elastomeric phase dispersed into a rigid matrix. The blends show higher thermal stability than polystyrene homopolymer due to the stabilizing effect of EPDM incorporation. The mechanical properties of in situ polymerized PS/EPDM blends with different compositions were evaluated before and after accelerated photoaging and compared with the properties of HIPS submitted to the same aging conditions. The blend containing 17 wt % of EPDM presents an increase in the impact resistance of 210% in comparison with the value of PS. Although the initial mechanical properties of HIPS are superior, a pronounced drop was observed after an exposure time. For example, after the aging period, all PS/EPDM blends showed higher strain at break than HIPS. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Can the environmental benefits of biomass support agriculture?—The case of cereals for electricity and bioethanol production in Northern Spain

Recent policy documents, such as the EC Communication on an Energy Policy for Europe (January 2007) make emphasis on the opportunities that energy applications can offer certain agricultural commodities, especially in the framework of a progressive dismantling of the Common Agricultural Policy. This paper analyses whether this can be true for wheat and barley farmers, using the real example of a straw-based power plant in Northern Spain and a theoretical factory for bioethanol production fed with cereal grain. The outcomes of such an exercise, in which their relative environmental benefits vis-à-vis fossil fuel alternatives are worked out with the aid of a simplified life-cycle approach, show that the characteristics of the electricity and biomass markets, the baseline scenario and the fuel prices are crucial for the future of the sector.     

Massive mesh hole repair minimizing user intervention

In constructing a model of a large twelfth century monument, we face the repair of a huge amount of small to medium-sized defects in the mesh. The total size of the mesh after registration was in the vicinity of 173M-triangles, and presented 14,622 holes of different sizes. Although other algorithms have been presented in the literature to fix these defects, in this case a fully automatic algorithm able to fix most of the defects is needed. In this paper we present the algorithms developed for this purpose, together with examples and results to measure the final surface quality. The algorithm is based on the iteration of smoothing and fitting steps on a uniform B-Spline defined on a 3D box domain bounding the hole. Tricubic and trilinear B-Splines are compared and the respective effectiveness is discussed.     

Diagnosis of Boards for Realistic Interconnect Shorts

Original algorithms and tools for generating diagnostic test setsfor board interconnect shorts, and assessing their diagnostic resolution areproposed. The test sets are derived from a representation of realisticshorts, extracted from the board layout. Diagnostic resolution isstatistically evaluated by simulating diagnosis of a sample of realisticshorts. The overall methodology is based on a new theoretical framework thataccounts for the probabilities of shorts, according to their multiplicityand possible logic behaviour. Results on real board layouts show that,compared to the traditional schemes, our test sets have higher diagnosticresolution, shorter test vectors, and can be produced efficiently.