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This study focused on an innovative and eco-friendly procedure to purify bioactive phenolic compounds (PC) from marine plants, i.e., two macroalgae Bifurcaria bifurcata and Codium fragile, and three halophytes Beta vulgaris subsp. maritima, Crithmum maritimum and Plantago lanceolata. The extraction was classically performed with aqueous ethanol followed by an eco-friendly purification procedure using a reusable Diaion HP-20 macroporous resin to reduce the use of toxic solvents and can be considered on a large scale. Purification monitoring was carried out by Folin-Ciocalteu assay to determine PC contents in fraction and proton nuclear magnetic resonance (1H NMR) to follow its efficiency. The bioactivities investigated were the radical-scavenging capacity and the antibacterial activity evaluated by EUCAST broth microdilution method on reference and clinical bacteria (Gram-positive and Gram-negative bacteria). The Diaion purification allowed the PC enrichment for all the species fractions combined with an increase of the radical-scavenging capacity. The B. bifurcata F30 fraction particularly emerged from the screening with antibacterial activity against all tested staphylococcal strains. In order to identify phlorotannins, the fractionation of this F30 fraction by Flash chromatography with an acetonitrile gradient, and its analysis using 2D NMR, revealed the presence of bioactive fucophlorethols for the first time in this species. The properties associated with the B. bifurcata F30 fraction can be valued for biotechnological applications as natural preservative and/or antimicrobial agents in cosmetics, food and medicine. These results demonstrate that the Diaion HP-20 is promising to purify bioactive PC from macroalgae and halophytes, in terms of efficiency and eco-friendly properties. [ABSTRACT FROM AUTHOR]

• In-depth scientific study of a rare painted shroud from a female Egyptian mummy. • Mummy dates to the 1st – 2nd century C.E. and was likely traced back to Upper Egypt. • Color palette consists of a few mineral pigments and plant-derived dyes. • Organic materials include animal fat, plant lipid, Pinaceae resin, gum, and beeswax. • Shroud and inner bandages were made of linen, now severely degraded. This article describes a multi-analytical technical study of a rare painted shroud still wrapped around a female Egyptian mummy (MCABo EG 1974) in the collection of the Museo Civico Archeologico of Bologna, Italy. Long stored in the museum's warehouses, these mummified human remains were recently rediscovered within the Bologna Mummy Project (BOmp), an interdisciplinary endeavor promoted by the Museo Civico Archeologico and the Institute for Mummy Studies of Eurac Research, Bolzano, Italy. Dating to the Roman period (1st-2nd century C.E.), as confirmed by radiocarbon dating, this mummy displays a unique series of technical features, including the exceptional finding of a colorful painted shroud still preserved in its original location around the wrapped body, to which it is secured with textile straps and resin. In this context, scientific analysis aimed to deepen our current knowledge of the artistic practices of Roman Egypt through an in-depth study of the painting technique, context of production, and possible provenance of the mummy, while promoting a science-informed, enhanced approach to the preservation of the mummified human remains. This research relied on an integrated analytical protocol based on the combined use of imaging and mapping techniques, non-invasive point analysis, and micro-invasive investigation of minute samples, each carried out at the different partnering institutions. Computed tomography (CT) highlighted varying radio-densities for some of the flesh tones and red decorations. Visible photography and multiband imaging provided information on the nature and distribution of various materials on the surface. Fiber optics reflectance spectroscopy (FORS), X-ray fluorescence (XRF) spectroscopy, and Raman spectroscopy contributed to the characterization of the shroud's color palette along with optical microscopy (OM), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), as well as high-performance liquid chromatography coupled with diode-array detection and mass spectrometry (HPLC/DAD and HPLC/MS). Materials detected include a limited number of mineral pigments and plant-derived dyes such as red lead, red ocher, madder, an unknown yellow dye, Egyptian blue and green, and a carbon-based black. Through access to MOLAB equipment and expertise, macro-XRF (MA-XRF), as well as combined X-ray diffraction (XRD) spot analysis and mapping, enhanced pigment identification. A combination of transmission Fourier-transform infrared (FTIR) spectroscopy with gas chromatography / mass spectrometry (GC/MS) was used to identify the paint binders and any additional organic substances possibly involved in embalming practices and ritual traditions, including animal fat, plant lipid, Pinaceae resin, gum, and beeswax. Mineralogical data gathered by XRD on surface deposits and soil residues collected from within the shroud's inner folds was crucial to put forward hypotheses, in support of the stylistic study of the shroud, concerning a possible provenance from Upper Egypt, most likely West Thebes. Both the shroud and inner bandages were found to be made with linen using OM. After undergoing scientific analysis and conservation treatment, the mummy was displayed in the "Mummies. Unwrapping the past" exhibition and was featured at the 10th World Congress on Mummy Studies, both held in Bolzano in the fall of 2022. [ABSTRACT FROM AUTHOR]

Valvular heart diseases (such as stenosis and regurgitation) are recognized as a rapidly growing cause of global deaths and major contributors to disability. The most effective treatment for these pathologies is the replacement of the natural valve with a prosthetic one. Our work considers an innovative design for prosthetic aortic valves that combines the reliability and durability of artificial valves with the flexibility of tissue valves. It consists of a rigid support and three polymer leaflets which can be cut from an extruded flat sheet, and is referred to hereafter as the Wheatley aortic valve (WAV). As a first step towards the understanding of the mechanical behavior of the WAV, we report here on the implementation of a numerical model built with the ICFD multi‐physics solver of the LS‐DYNA software. The model is calibrated and validated using data from a basic pulsatile‐flow experiment in a water‐filled straight tube. Sensitivity to model parameters (contact parameters, mesh size, etc.) and to design parameters (height, material constants) is studied. The numerical data allow us to describe the leaflet motion and the liquid flow in great detail, and to investigate the possible failure modes in cases of unfavorable operational conditions (in particular, if the leaflet height is inadequate). In future work the numerical model developed here will be used to assess the thrombogenic properties of the valve under physiological conditions. [ABSTRACT FROM AUTHOR]

The aim of this paper is to address the predominantly conflictive nature of interethnic relations in the context of the Spanish colonial settlements established in the Valdés Peninsula (Chubut province, República Argentina): San José Fort and Puesto de la Fuente (1779-1810). We specifically present, describe and examine the episodes of inter-ethnic tensions and violence in these settlements over time. To achieve this, we will focus on the analysis and critical discussion of the information provided by the primary sources throughout the 31 years of occupation. Understanding the uniqueness of intercultural relations in these scenarios necessarily involved approaching them from a comparative perspective, by considering their broader historical and regional trajectory in Patagonia in the time period investigated. Consequently, we were able to identify the prominent role of indigenous groups from Southern Patagonia and recognize multiple factors contributing to the genesis of the indigenous raids experienced by these colonial settings. These results unveil the complex network of intercultural connections and colonial relations during the late colonial period in Patagonia. [ABSTRACT FROM AUTHOR]

In the present work, composite ceramics of BaTiO3 with La0.08Pb0.92Ti0.20Zr0.80O3 were prepared from powders synthesized by two different methods: (a) PLZT@BT ceramics from core-shell powders with PLZT-core and BaTiO3 shell and (b) PLZT-BT ceramic composites from mixed PLZT and BaTiO3 powders. In core-shell ceramics, a thin conductive layer of BaPbO3 was formed that resulted in an increased effective permittivity with relatively low losses (tan δ<0.7 in kHz regions). The extrinsic contributions play an important role in both ceramics, but they are more evident in core-shell samples due to the large number of interfaces. These results show that novel functional properties can be tailored by the controlled chemical reaction at interfaces. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mixotrophy in a tubular photobioreactor was mimicked by the tank-in-series approach. • The investigation of the retention time distribution led to a tank number of 100. • Different PID configurations were compared for oxygen stability with constant light. • The chosen controller kept stable oxygen levels also under outdoor light conditions. • Scale-down validation proved oxygen predictions but showed faster dynamics in vivo. Scaling up bioprocesses remains challenging due to the partially unpredictable and suboptimal behavior of microbes during scale transition. Mathematical modelling serves as a valuable tool in navigating these challenges. In this study, we developed and validated a kinetic model based on the tank-in-series approach for a novel bioprocess known as oxygen-balanced mixotrophy with the microalga Galdieria sulphuraria. This model aims to facilitate the design of an effective glucose feeding control strategy tailored for two-phase tubular photobioreactors (TPBRs). The residence time distribution of our reference reactor was investigated by means of a tracer experiment. Qualitative analysis of the results indicated that our system was optimally represented by simulations with a 100 stirred-tank reactors (STRs). The controlled variable, oxygen concentration in the gas phase, showed a downward trend in simulations with simplified conditions: fixed oxygen production and balanced glucose supply. The decrease was caused by dominant net heterotrophic activity and accumulation of CO 2 in the gas phase. Different configurations of a proportional-integral-derivative (PID) controller were designed by means of the ultimate gain method and compared under these simplified conditions. The most effective PID controller was implemented and refined in simulations with outdoor weather conditions. The model was validated successfully by simulating over time in a lab-scale STR the spatial fluctuations happening in a TPBR. The empirical oxygen consumption and production were faster and steeper than in the model, probably due to inaccuracies in parameter estimation or biomass adaptation. [ABSTRACT FROM AUTHOR]

Pure perovskite Ba0.90Ca0.10TiO3 ceramics, with a relative density of between 79 and 98% and grain sizes larger than 1 µm, were prepared by solid-state reaction. The dielectric and electrocaloric properties were investigated and discussed considering the density and grain size of the samples. Room temperature impedance measurements show good dielectric properties for all ceramics with relative permittivity between 800 and 1100 and losses of <5%. Polarization vs. E loops indicates regular variation with increasing sintering temperature (grain size and density), an increase in loop area, and remanent and saturation polarization (from Psat = 7.2 µC/cm2 to Psat = 16 µC/cm2). The largest electrocaloric effect was 1.67 K for ceramic with GS = 3 µm at 363 K and electrocaloric responsivity (ζ) was 0.56 K mm/kV. These values are larger than in the case of other similar materials; thus, Ba0.90Ca0.10TiO3 ceramics with a density larger than 90% and grain sizes of a few µms are suitable materials for electrocaloric devices. [ABSTRACT FROM AUTHOR]

The melanocortin receptor accessory protein 2 (MRAP2) is essential for several physiological functions of the ghrelin receptor growth hormone secretagogue receptor 1a (GHSR1a), including increasing appetite and suppressing insulin secretion. In the absence of MRAP2, GHSR1a displays high constitutive activity and a weak G-protein–mediated response to ghrelin and readily recruits β-arrestin. In the presence of MRAP2, however, G-protein–mediated signaling via GHSR1a is strongly dependent on ghrelin stimulation and the recruitment of β-arrestin is significantly diminished. To better understand how MRAP2 modifies GHSR1a signaling, here we investigated the role of several phosphorylation sites within the C-terminal tail and third intracellular loop of GHSR1a, as well as the mechanism behind MRAP2-mediated inhibition of β-arrestin recruitment. We show that Ser252 and Thr261 in the third intracellular loop of GHSR1a contribute to β-arrestin recruitment, whereas the Cterminal region is not essential for β-arrestin interaction. Additionally, we found that MRAP2 inhibits GHSR1a phosphorylation by blocking the interaction of GRK2 and PKC with the receptor. Taken together, these data suggest that MRAP2 alters GHSR1a signaling by directly impacting the phosphorylation state of the receptor and that the C-terminal tail of GHSR1a prevents rather than contribute to β- arrestin recruitment. [ABSTRACT FROM AUTHOR]

As part of the "TT8 Project", several research groups examined the grave goods from the Theban Tomb No. 8 of Kha and his wife Merit who lived during the second half of 18th dynasty and were discovered by the Italian Archaeological Mission led by Ernesto Schiaparelli. Thanks to the collaboration of Egyptologists, conservators, and scientists, numerous state-of-the-art, non-invasive methods were used to examine and characterize the objects found in the tomb. During this comprehensive investigation, for which a fully non-invasive approach was designed, the preliminary results for three polychrome wooden caskets showed the unexpected presence of manganese in the black areas in combination with the carbon black ink also present in the black decorations. In addition to MA-XRF analysis, which allowed for the discovery, an innovative imaging method was applied for faster discrimination of black pigments. This method is based on the optical spectral differences between manganese-based blacks and carbon black in the short-wave infrared – with a maximum difference in the range of 1400–1700 nm – and is comparable to a photograph in terms of acquisition time. By using an InGaAs camera with an interferential long-pass filter of 1400 nm, the images were acquired first on a series of mock-ups and then on the wooden caskets. Using false color imaging representation, the areas painted with manganese black showed a clear red false color, in contrast to the black false color of the areas painted with carbon black. The results are fundamental to understanding whether the use of manganese black could be more widespread than reported in the literature so far. • Non-invasive methods were used to examine Theban Tomb No. 8's grave goods of Kha and Merit. • Manganese black was found in black areas of the wooden caskets, combined with carbon black. • Surprisingly manganese black was used mostly in one casket, for hieroglyph and figure contours. • MA-XRF analysis led to discovering manganese presence in black decorations. • SWIR false color imaging distinguished manganese black from carbon-based black. [ABSTRACT FROM AUTHOR]

The article describes the experience of adapting the subject "Real Educational Challenges" to the virtual modality during the COVID-19 pandemic. It highlights the use of digital tools to improve teacher monitoring and student collaborative work. However, it mentions the limitation of not being able to carry out fieldwork in person. The article invites us to rethink university teaching practices, taking into account the value of technology to enrich online education, but also recognizing the importance of face-to-face interaction. [Extracted from the article]

The influence of the oxygen vacancies on the dielectric response of BaZr0.10Ti0.90O3 ceramics prepared by solid-state reaction and sintered at 1400 °C for 2 h was investigated. The as-sintered ceramic exhibits a giant relaxation with a shift of the transition temperature from ∼85 °C to above 170 °C in the frequency ranges of 1 Hz-100 kHz, with high losses above unity and two components in the complex impedance plot. A complex dielectric relaxation response, with at least two thermally activated defect mechanisms with activation energies of ∼0.2 eV below the transition temperature and ∼0.7 eV for higher temperatures in the range of 85 °C-170 °C was determined. The observed giant relaxation is an extrinsic effect related to the oxygen deficiency, inhomogeneous distributed in the ceramic grain and not to the relaxor behavior of this system. After a post-annealing treatment at 1000 °C for 50 h, the dielectric response is completely changed: the permittivity vs. temperature dependences present maxima located at around Tm ≈ 90 °C, with almost no frequency dispersion. The conductivity spectra remained almost unchanged after the annealing, showing that the level of oxygen deficiency in this case is related to dielectric relaxations and not to the ac-conductivity dispersion. Two thermally activated dielectric relaxation processes were still identified, but with activation energies of ∼2.7 eV below the transition temperature and of ∼0.87 eV for higher temperatures in the range of 85 °C-170 °C. The high frequency relaxation process is almost suppressed by the reoxidation and its activation energy increased with more than one order in magnitude. One single component in the complex impedance plot found after reoxidation shows that the annealing allowed the homogenization of the oxygen level within the ceramic grains. [ABSTRACT FROM AUTHOR]

In the present work, diphasic ceramic composites with core-shell nanostructures formed by Ni0.50Zn0.50Fe2O4 core and BaTiO3 shell were investigated. Their properties were compared with those of composites prepared by coprecipitation. The core-shell structure was confirmed by microstructural powder analysis. Homogeneous microstructures with a good phase mixing and percolated dielectric phase by the magnetic one were obtained from coprecipitated powders. Less homogeneous microstructures resulted in ceramics produced from the powder prepared by core-shell method, with isolated small ferrite grains besides large ferrite aggregates embedded into the BaTiO3 matrix. Both the ferroelectric and magnetic phases preserve their basic properties in bulk composite form. However, important differences in the dielectric relaxation and conduction mechanisms were found as result of the microstructural difference. Extrinsic contributions play important roles in modifying the electric properties in both ceramics, causing space charge effect, Maxwell–Wagner relaxations and hopping conductivity, mainly due to the ferrite low resistivity phase. The conductivity and dielectric modulus spectra analysis allowed to identify different polaron contributions associated with the microstructural differences. It results that by using the core-shell method, improved dielectric properties and limited hopping contributions can be realized. [ABSTRACT FROM AUTHOR]

The defect chemistry of Yb3+:CaTiO3 solid solutions has been investigated both theoretically and experimentally. Three different incorporation mechanisms with similar solution energy were predicted for Yb3+ by atomistic simulation: (i) Ca site substitution with Ca vacancy compensation; (ii) Ti site substitution with O vacancy compensation; (iii) simultaneous substitution at both Ca and Ti sites with self-compensation. X-ray diffraction and scanning electron microscopy results strongly support the possibility to realize the above defect chemistries in CaTiO3 by changing the Ca/Ti ratio to force Yb3+ on the Ca site (Ca/Ti<1), on Ti site (Ca/Ti>1), or on both sites (Ca/Ti=1) according to the calculations. The temperature dependence of the relative dielectric constant (102–105 Hz) of ceramics corresponding to predominant Yb substitution either at the Ca site or the Ti site is qualitatively similar to that of undoped CaTiO3. The Curie-Weiss temperature is shifted to more negative values in comparison to CaTiO3, suggesting that the compositions Ca1-3/2xYbxTiO3 and CaYbxTi1-xO3 are further driven away from the ferroelectric instability. In contrast, the dielectric properties (102–105 Hz) of ceramics corresponding to Ca1-x/2YbxTi1-x/2O3 are radically different. The relative dielectric constant is increased of about one order of magnitude (2200 at 30 K), is almost independent of temperature, with a maximum variation of 20% in range of 20–300 K, and shows frequency dispersion above 150 K. The loss tangent at 20–300 K is <5% for frequencies >=1 kHz. The possible mechanism for the observed dielectric behavior is discussed. [ABSTRACT FROM AUTHOR]

The multidisciplinary and multi‐technical study of the coffin lid of Neskhonsuennekhy (Turin, Museo Egizio, inventory number S.05245) datable to the 26th dynasty (664–525 BC) was launched in 2015 at the Centro Conservazione e Restauro La Venaria Reale during the conservation activities required by the Museo Egizio, as part of wider research on the so‐called red coffins. Widespread abrasions and gaps in the pictorial stratigraphy strongly impeded the reading of the decoration, and a reddish and locally blackened material was covering many areas. Integrating multispectral imaging (UV fluorescence, VIL, IR reflectography), MA‐XRF, radiography, and analyses on micro‐samplings (OM, SEM‐EDX, FT‐IR) allowed deepening the state of preservation, detecting previous intervention, and characterizing the blackened surface, necessary to define the cleaning intervention objectives. In particular, the IR reflectography allowed recovering the readability of the beautiful drawings and the ancient hieroglyphs hidden beneath the reddish blackened surface. Based on the analytical data and compatibility with the pigments known in ancient Egypt, it was possible to return to the public the original lost decoration with a descriptive and virtual reconstruction. The new LANDIS‐X scanning station equipped with a real‐time macro XRF was fundamental for studying pigments, glazes, and mixtures besides the presence of lead impurities in the copper source used to make the Egyptian blue pigment, encouraging the research on the sources of mineral supply. Finally, this study allowed understanding the technique of execution of the find, from the assembly of the wooden elements to the reddish finish, noticing analogies with the other red coffins. [ABSTRACT FROM AUTHOR]

The most common method for modeling forest attributes with airborne lidar, the area-based approach, involves summarizing the point cloud of individual plots and relating this to attributes of interest. Tree- and voxel-based approaches have been considered as alternatives to the area-based approach but are rarely considered in an area-based context. We estimated three forest attributes (basal area, overstory biomass, and volume) across 1680 field plots in Arizona and New Mexico. Variables from the three lidar approaches (area, tree, and voxel) were created for each plot. Random forests were estimated using subsets of variables based on each individual lidar approach and mixtures of each approach. Boruta feature selection was performed on variable subsets, including the mixture of all lidar-approach predictors (KS-Boruta). A corrected paired t test was utilized to compare six validated models (area-Boruta, tree-Boruta, voxel-Boruta, KS-Boruta, KS-all, and ridge-all) for each forest attribute. Based on significant reductions in error (SMdAPE), basal area and biomass were best modeled with KS-Boruta, while volume was best modeled with KS-all. Analysis of variable importance shows that voxel-based predictors are critical for the prediction of the three forest attributes. This study highlights the importance of multiresolution voxel-based variables for modeling forest attributes in an area-based context. [ABSTRACT FROM AUTHOR]

The multidisciplinary and multi‐technical study of the coffin lid of Neskhonsuennekhy (Turin, Museo Egizio, inventory number S.05245) datable to the 26th dynasty (664–525 BC) was launched in 2015 at the Centro Conservazione e Restauro La Venaria Reale during the conservation activities required by the Museo Egizio, as part of wider research on the so‐called red coffins. Widespread abrasions and gaps in the pictorial stratigraphy strongly impeded the reading of the decoration, and a reddish and locally blackened material was covering many areas. Integrating multispectral imaging (UV fluorescence, VIL, IR reflectography), MA‐XRF, radiography, and analyses on micro‐samplings (OM, SEM‐EDX, FT‐IR) allowed deepening the state of preservation, detecting previous intervention, and characterizing the blackened surface, necessary to define the cleaning intervention objectives. In particular, the IR reflectography allowed recovering the readability of the beautiful drawings and the ancient hieroglyphs hidden beneath the reddish blackened surface. Based on the analytical data and compatibility with the pigments known in ancient Egypt, it was possible to return to the public the original lost decoration with a descriptive and virtual reconstruction. The new LANDIS‐X scanning station equipped with a real‐time macro XRF was fundamental for studying pigments, glazes, and mixtures besides the presence of lead impurities in the copper source used to make the Egyptian blue pigment, encouraging the research on the sources of mineral supply. Finally, this study allowed understanding the technique of execution of the find, from the assembly of the wooden elements to the reddish finish, noticing analogies with the other red coffins. [ABSTRACT FROM AUTHOR]

To explore the factors impacting abortion access for abortion fund clients, data from 816 applicants was analyzed using a summative content analysis approach. Nine relationship themes emerged for applicants who cited their partner as a significant factor in their abortion decision-making, including (a) power and control, (b) fear and safety concerns, (c) leaving the relationship, (d) barriers to accessing care, (e) sexual violence, (f) perpetration and victimization, (g) having an unsupportive partner, (h) being partnerless, and (i) having a supportive partner. Abortion funds are a potential resource for those experiencing intimate partner violence and can support survivors through confidential care and referrals. [ABSTRACT FROM AUTHOR]

The amazing properties of ferroelectric perovskite BaTiO3 (BT) and its solid solutions make them indispensable for many technological applications (e.g. multilayer capacitors). Unfortunately, the so‐called 'size effect' limits their use. Indeed, under a certain critical particle size, these materials show a suppression of the spontaneous polarization and thus of the ferroelectric properties. In pure nanometric BaTiO3, this is related to a certain local structural disorder. However, only a few studies have explored BT solid solutions, where the doping effect, coupled to the reduced particle size, can play an important role. Therefore, in this work, the structure of BaCexTi1–xO3 (x = 0.02–0.20) was explored by traditional Rietveld method and Pair Distribution Function. Samples present a particle size from 80–160 nm to 400–1000 nm depending on increasing x. The carbox approach was applied, investigating the evolution of the local structure, its modifications and the structural coherent correlation length, as a function of cerium amount. Results demonstrate a cooperative effect of composition and reduced size in the ferroelectricity loss. The two, in fact, contribute to intensify the local structural disorder, decreasing the structural coherent correlation length. The local structural disorder is thus confirmed to be a relevant factor in the ferroelectric properties degradation. [ABSTRACT FROM AUTHOR]

A 19‐year‐old female chimpanzee (Pan troglodytes) presented for cachexia, acute weakness, hyporexia, icterus, and polyuria. The animal was diagnosed with a hyperglycemic hyperosmolar state, which is a well‐recognized syndrome in diabetic humans that is rarely diagnosed in animals. This case documents an important and likely under‐reported syndrome in non‐human primates. [ABSTRACT FROM AUTHOR]

A 21-year-old male southern rockhopper penguin (Eudyptes chrysocome) was presented with a chronic history of intermittently decreased appetite, lethargy, and regurgitation. On the external physical examination, the bird was determined to be in fair-to-thin body condition with the complete blood count and plasma chemistry panel being largely unremarkable. Full-body radiographic images were considered normal, and gastroscopy showed only mild gastritis and duodenitis. The penguin was euthanatized shortly thereafter due to acute onset of respiratory distress. During the gross necropsy examination, the bird had severe airsacculitis with thick, yellow-to-tan, moist granular plaques adhering to the surface of many air sacs, as well as regional contiguous pneumonia. Intralesional acid-fast bacilli were observed in histologic sections of air sac tissue, and polymerase chain reaction of the affected air sacs was positive for Mycobacterium fortuitum. This clinical case study describes mycobacteriosis in a sub-Antarctic penguin and to the best of the authors' knowledge, the first reported isolation of M fortuitum from a penguin. [ABSTRACT FROM AUTHOR]

Ferroelectric perovskites such as BaTiO 3 and Pb(Zr,Ti)O 3 are well-suited for a variety of applications including piezoelectric transducers and actuators, multilayer ceramic capacitors, thermistors with positive temperature coefficient, ultrasonic and electro-optical devices. Ferroelectricity arises from the long-range ordering of elemental dipoles which determines the appearance of a macroscopic polarization and a spontaneous lattice strain. The confinement of a ferroelectric system in a small volume produces a perturbation of the polar order because of the high fraction of surface atoms and ferroelectricity vanishes when the size of the material is reduced below a critical dimension. This critical size is of a few nanometres in the case of epitaxial thin films and of 10−20 nm for nanoparticles and nanoceramics. The change in properties with decreasing physical dimensions is usually referred to as size effect. Thin films and ceramics are particularly prone to show size effects. A progressive variation of dielectric, elastic and piezoelectric properties of ferroelectric ceramics is already observed when the grain size is reduced below ≈10 μm, i.e. at a length scale much larger than the critical size. In this case it is more appropriate to refer to scaling effects as they are not related to material confinement. The aim of this contribution is to review the current understanding of size and scaling effects in perovskite ferroelectric ceramics and, in particular, in BaTiO 3. After a short survey on the intrinsic limits of ferroelectricity and on the impact of particle/grain size on phase transitions, the role of interfaces such as ferroelectric/ferroelastic domain walls and grain boundaries in scaling of dielectric and piezoelectric properties will be discussed in detail. Multiple mechanisms combine to produce the observed scaling effects and the maximization of the dielectric constant and piezoelectric properties exhibited by BaTiO 3 ceramics for an intermediate grain size of ≈1 μm. The broad dispersion of experimental data is determined by spurious effects related to synthesis, processing and variation of Ba/Ti ratio. Furthermore, we will consider these size effects, and other properties in relation to the downsizing the modern multilayer BaTiO 3 based capacitors. [ABSTRACT FROM AUTHOR]

High mountain lakes provide essential ecosystem services and have a high conservation value. Therefore, understanding how glacier retreat will affect their ecological functioning and water quality is crucial. Here, we tested how shallow high mountain lakes having different glacial influences differ in their abiotic main features and food web structure using a multiple ecological indicator approach. We identified 13 functional groups within the planktonic and littoral communities, each one representing a biotic indicator and a node in a simplified food web network. The abiotic environment and most functional groups differed significantly as a consequence of the glacial influence. In general, runoff from glacial meltwaters resulted in highly simplified food webs. Considering that many turbid glacially fed lakes are losing their hydrological connection with disappearing/retreating glaciers and shifting to a clear state, our results suggest that this shift could enhance food web complexity, but at the cost of losing specific habitats. Further, retreat of large glaciers will form new glacially fed lakes, but it remains unclear whether this will buffer the expected habitat and biodiversity loss. [ABSTRACT FROM AUTHOR]

This article focuses on the analysis of the pigmentary palette of Pío Collivadino (1869–1945), an Argentinian artist of outstanding influence in the national art of the early twentieth century. By using Raman spectroscopy on micro-samples taken from a selected corpus of the Pío Collivadino Museum consisting of representative works of different moments of his production, we were able to unambiguously detect several pigments in the artist's palette: lead white, vermillion, Prussian blue, chrome yellows and oranges, synthetic ultramarine, zinc white, cadmium yellows and oranges, cobalt violet, viridian, cerulean blue, cadmium red and earth pigments (raw sienna and burnt sienna). The identification of the pigments used by Collivadino enabled us to set up a dialogue between his palette and those of the contemporary European artistic movements his work relates to: the Macchiaioli , the Scapigliati , the Divisionists (Italian artistic vanguards) and the Impressionists. The presence of Prussian blue, cerulean blue, viridian not mixed with emerald green and earth pigments relates Collivadino's choice of pigments to that of the contemporary Italian artistic vanguards, distancing his palette from that of the Impressionists. The palettes of European artists active during the nineteenth century and the first half of the twentieth century have been widely studied making it possible to date the incorporation of the new bright and colorful pigments that were synthesized during this period. Taking into account Collivadino's privileged position in the Art academic field, his choice of art materials may have influenced many artists whose works make up the Argentine national heritage. Therefore, the characterization of Collivadino's pigmentary palette carried out here is an important step to date the incorporation of these bright new pigments in the Argentinian artists' palettes. Besides Collivadino's work importance by itself, and due to his position of privilege, his palette also provides information about the availability of art supplies in Argentina during this period. [ABSTRACT FROM AUTHOR]

This study focuses on the contraceptive experiences of abortion-fund applicants to draw attention to various elements that restrict the realization of reproductive justice in the Rocky Mountain Region of the United States. This study uses qualitative data from 830 applications to an abortion fund submitted between 2013 and 2022. Our findings highlight a range of experiences, from contraceptive failure and side effects, to diminished access and reproductive coercion. Abortion-fund applicants described individual, interpersonal, and structural factors that shaped their access to contraception. This study calls for various interventions, including implementing comprehensive sex education, to ensure reproductive justice. [ABSTRACT FROM AUTHOR]

Objectives Human epidermal growth factor receptor 2 (HER2) is expressed in some gastric and gastroesophageal junction adenocarcinomas. There were two goals: assess the impact of specimen type on HER2 status and evaluate HER2 concordance with multiple specimens. Methods All cases were evaluated by immunohistochemistry (IHC) for HER2 and interpreted using established criteria. Fluorescence in situ hybridization (FISH) was performed on a subset. Results Of 460 specimens, 83.9% were IHC negative, 5.4% were equivocal, and 10.7% were IHC positive. Of those with FISH testing, 78.5% were FISH negative, and 21.5% were FISH positive. IHC-FISH concordance for biopsy specimens, resections, and metastases was 82%, 84%, and 86%, respectively. With one vs two vs three or more specimens, the HER2-positive rate increased from 10.5% to 18.1% to 24.1%, respectively. Conclusions HER2 testing may be performed on biopsy specimens with a relatively high concordance rate with resection specimens, and if multiple samples are analyzed from a single patient, the HER2-positive rate increases over twofold. [ABSTRACT FROM AUTHOR]

Cloacal swabs and feces were collected for four consecutive months from 19 young, healthy Burmese pythons (Python bivittatus) that were culture-confirmed, asymptomatic carriers of Salmonella enterica ssp. arizonae (S. arizonae). Standard culture protocols were used on 152 samples in total (76 fecal samples and 76 cloacal swabs). Comparison of the two sampling methods for each month and over the combined 4 months using McNemar's χ2 test revealed that the two methods were not statistically different at the P < 0.05 level. However, of the cloacal swabs, 71 (93%) of 76 samples yielded positive cultures of S. arizonae, 15 (79%) of 19 snakes had no negative cloacal swabs, 1 (5%) snake had more than one negative cloacal swab (but not consecutively), and all snakes had positive cultures in two of the months. Of the fecal samples, 64 (84%) of 76 samples yielded positive cultures of S. arizonae, 13 (68%) of 19 snakes had no negative fecal samples, 4 (21%) snakes had more than one negative fecal sample (3 of which were in consecutive months), and all months had at least one negative culture. Serotyping of confirmed S. arizonae isolates identified three different serotypes. This study provides the first evidence-based data to support the statistical equivalency of cloacal swabs and fecal samples for the isolation of Salmonella from reptiles. Cloacal swabs are easy and convenient to collect and are less prone to confounding factors than are fecal samples, so clinicians can feel comfortable using this sample collection method. [ABSTRACT FROM AUTHOR]

Abstract The coupling of Reynolds and Rayleigh-Plesset equations has been used in several works to simulate lubricated devices considering cavitation. The numerical strategies proposed so far are variants of a staggered strategy where Reynolds equation is solved considering the bubble dynamics frozen, and then the Rayleigh-Plesset equation is solved to update the bubble radius with the pressure frozen. We show that this strategy has severe stability issues and a stable methodology is proposed. The proposed methodology performance is assessed on two physical settings. The first one concerns the propagation of a decompression wave along a fracture considering the presence of cavitation nuclei. The second one is a typical journal bearing, in which the coupled model is compared with the Elrod-Adams model. Highlights • A stable numerical method is proposed for coupling the Reynolds and Rayleigh-Plesset equations: The One-Step Method. • The proposed method is shown to be more robust than the popular staggered method. • Unconditional zero-stability is proved. • The One-Step Method allows to study a decompression wave along a fracture with cavitation nuclei attached to the walls. • The Reynolds-Rayleigh-Plesset model and the Elrod-Adams model are compared numerically in the journal bearing geometry. [ABSTRACT FROM AUTHOR]

Background: Clinical assays for the assessment of the human epidermal growth factor receptor-2 (HER2) status in breast cancer include immunohistochemistry (IHC) and in situ hybridization (ISH), both of which have limitations. Recent studies have suggested that a more quantitative approach to the measurement of HER2 protein expression may improve specificity in selecting patients for HER-2 targeted therapy. In the current study, we have used HER2 expression in breast cancer cell lines and clinical samples as a model to explore the potential utility of a novel immunodetection technique, using streptavidin coated Phosphor Integrated Dot fluorescent nanoparticles (PID), which can be quantitatively measured using computer analysis.Methods: The expression of HER2 protein in cell lines was evaluated with antibody-binding capacity using fluorescence-activated cell sorting (FACS) for comparison with PID measurements to test for correlations with existing quantitative protein analysis methodologies. Various other analytic validation tests were also performed, including accuracy, precision, sensitivity, robustness and reproducibility. A methods comparison study investigated correlations between PID versus IHC and ISH in clinical samples. Lastly, we measured HER2 protein expression using PID in the pretreatment biopsies from 34 HER2-positive carcinomas that had undergone neoadjuvant trastuzumab-based chemotherapy.Results: In the analytic validation, PID HER2 measurements showed a strong linear correlation with FACS analysis in breast cell lines, and demonstrated significant correlations with all aspects of precision, sensitivity, robustness and reproducibility. PID also showed strong correlations with conventional HER2 testing methodologies (IHC and ISH). In the neoadjuvant study, patients with a pathologic complete response (pCR) had a significantly higher PID score compared with patients who did not achieve a pCR (p = 0.011), and was significantly correlated to residual cancer burden (RCB) class (p = 0.026, R2 = 0.9975).Conclusions: Analytic testing of PID showed that it may be a viable testing methodology that could offer advantages over other experimental or conventional biomarker diagnostic methodologies. Our data also suggests that PID quantitation of HER2 protein may offer an improvement over conventional HER2 testing in the selection of patients who will be the most likely to benefit from HER2-targeted therapy. Further studies with a larger cohort are warranted. [ABSTRACT FROM AUTHOR]

Ceramics with perovskite structure and composition BaCexTi1−xO3 (x = 0.02–0.30) show a progressive evolution with increasing x, from the long‐range polar order of ferroelectric BaTiO3 to the short‐range polar order typical of relaxors. The ionic size mismatch between Ti4+ and Ce4+ determines strong local strains which have a significant impact on dielectric properties and phase transitions. The pair distribution function, coupled with transmission electron microscopy analysis, was applied to study the local structure. Because of the inner B‐cation sizes, the superposition of rigid B—O octahedra with different volumes is not compatible with the construction of an ideal perovskite structure. In this light, local structure can be described by an original model which allows (i) different Ti—O and Ce—O distances and (ii) the typical distortions of the two end members: off‐center displacement of Ti occurring in BaTiO3 and octahedral tilt in BaCeO3. The results show a clear difference, in terms of volumes, between oxygen octahedra with titanium and those related to cerium. In addition, the inclusion of cerium causes a tilt of its oxygen cage, as occurs in pure BaCeO3, creating contra‐rotations and distortions of the octahedra containing titanium. This complex arrangement entails a substantial distortion, increasing as a function of cerium amount, which strongly influences the directions of titanium displacements, their local correlation and consequently their long‐range cooperative effects. [ABSTRACT FROM AUTHOR]

Background: Mitral valve aneurysms (MVAs) are uncommon conditions frequently associated with aortic valve endocarditis. They may be complicated by perforation and severe mitral regurgitation (MR). Optimal treatment of MVA, and in particular the best timing for surgery, are uncertain. Case Report: A 62-year-old man with a recent history of dental surgery presented to the Emergency Department complaining relapsing fever. A first echocardiogram demonstrated infective endocarditis of the aortic valve. The patient was primarily managed with specific antibiotic therapy. Despite this, a few days later he suffered from splenic embolization and an MVA with MR was detected. Surgical replacement of the mitral and aortic valves was therefore performed. Conclusions: MVAs are infrequent but potentially severe complications of AV endocarditis. In the absence of definite treatment indication, the correct time for surgery should depend on concomitant clinical and infective features. [ABSTRACT FROM AUTHOR]

Objective: Rare disease. Background: Spontaneous coronary artery dissection is the most common etiology of pregnancy-associated myocardial infarction. It is characterized by high rates of maternal morbidity and mortality and may cause fetal complications and death as well. Case Report: A 44-year-old female (G2P1) suffered from pregnancy-related spontaneous coronary artery dissection with dissection of distal left anterior descending coronary artery. The patient was hemodynamically stable and did not required revascularization, but signs of fetal distress were detected and thus an urgent cesarean delivery was performed. This emergency procedure was undertaken in the catheterization laboratory (Cath-Lab) right after coronary angiography, thanks to a multidisciplinary team. Health conditions of the newborn were good. The patient instead suffered from a recurrence of spontaneous coronary artery dissection 6 days later, complicated by left ventricular apical thrombus and epistenocardial pericarditis. The dissection self-healed in 1 month. Conclusions: Careful evaluation of pregnancy-related spontaneous coronary artery dissection is needed to assess and manage both maternal and fetal complications. Under specific circumstances, a cesarean delivery may be required and be even performed in the Cath-Lab after coronary catheterization. [ABSTRACT FROM AUTHOR]

Permittivity, tunability, and ferroelectric properties can be tailored to meet specific requirements for applications by combining ferroelectric (BaTiO3-BT) and antiferroelectric (La0.04Pb0.96Ti0.1Zr0.9O3- PLZT) and by exploiting interdiffusion and grain size effects at nanoscale. The dielectric properties, dc-tunability, and P(E) loops of ferroelectric-antiferroelectric nanostructured composites produced from mechanically mixed powders (PLZT-BT) and from core-shell particles (PLZT@BT) were comparatively analyzed. Interdiffusion accompanied by local composition gradients occurred during sintering of PLZT@BT composites and caused a thermally stable permittivity. Permittivity was reduced below 1000 in both cases (900 for PLZT-BT and 290 for PLZT@BT), while preserving tunability to 1.2-1.4 (E=40 kV/cm), with a linear field dependence. [ABSTRACT FROM AUTHOR]

Abstract: A series of La-doped (10at.%) SrTiO3 ceramics with grain size ranging from 6μm to 24nm was prepared from nanocrystalline powders using high-pressure field assisted sintering (HP-FAST). A progressive reduction of thermal conductivity κ with decreasing grain size was observed. At room temperature, κ of the ceramic with grain size of 24nm (1.2Wm−1 K−1) is one order of magnitude lower than that of undoped single crystals. The strong suppression of κ can be ascribed to (i) the high concentration of lattice defects, (ii) the increasing contribution of grain boundaries to phonon scattering when the grain size is decreased to the nanoscale and (iii) a moderate amount (10–15vol.%) of nanopores. These results demonstrate that nanostructuration can be a successful strategy to attain a considerable reduction of κ in heavily doped bulk oxide ceramics. The low electrical conductivity of the La:SrTiO3 nanoceramics represents a major obstacle for thermoelectric applications. [Copyright &y& Elsevier]

This paper highlights the agency of indigenous peoples in the manipulation, alteration, and/or definition of limits to the colonial order established in Patagonia by the end of the eighteenth century. Hence, it rests on the ideas of the ambivalence of power and intercultural relations. Interethnic relationships are explored in two case studies from the same colonizing project: 'Nueva Colonia y Fuerte de Floridablanca' (San Julián Bay, Santa Cruz province) and 'Fuerte San José' (Valdés peninsula, Chubut province). Social practices, material conditions of the colonial settlements, and particularly, the indigenous perceptions of the colonial posts are thoroughly considered. This information is thus intended to discuss the divergent trajectories of interethnic relationships, as well as to approach colonialism in Patagonia from the natives' logics. [ABSTRACT FROM AUTHOR]

This article highlights the recent developments on the hydrothermal and solvothermal synthesis of strontium titanate (SrTiO3), considered as a model system, by reviewing the literature of the last 10–15 years. The most significant advantage of these solution-mediated crystallisation methods is the effective control of particle composition, size and morphology by varying some physical and chemical parameters such as temperature, concentration, pH and solvent composition, as well as using different precursors and mineralisers, and moreover, adding growth modifiers like polar organic molecules and hydrophilic polymers. Thus, the synthesis process can be designed to obtain pure and doped materials with superior functional and photocatalytic properties, including monodispersed nanoparticles, platelets, wires, porous particles, mesocrystals and heterostructures. The hydrothermal crystallisation mechanisms are critically discussed, considering both the thermodynamic and kinetic aspects. In particular, the nature and morphology of the solid titanium precursor has a significant impact on the hydrothermal crystallisation as in many cases the formation of SrTiO3 occurs on the precursor surface. The dissolution of the precursor and the nucleation and growth of the perovskite are coupled together over rather short distances, and the coupling is mediated by the solid/liquid interfaces. The morphology of strontium titanate is thus determined by the precursor/perovskite crystallographic matching, the surface density of nuclei and the rate-controlling process. Differently, crystallisation from Sr–Ti amorphous gel-like precursors occurs in the absence of crystalline surfaces and often produces mesocrystals by oriented aggregation of the primary nanocrystals. These considerations have a general validity and can be extended to many ternary and even more complex oxides. [ABSTRACT FROM AUTHOR]

The conservation of artworks requires a profound knowledge about pictorial materials, their chemical and physical properties and their interaction and/or degradation processes. For this reason, pictorial materials databases are widely used to study and investigate cultural heritage. At Centre for Conservation and Restoration La Venaria Reale, we prepared a set of about 1200 mock-ups with 173 different pigments and/or dyes, used across all the historical times or as products for conservation, four binders, two varnishes and four different materials for underdrawings. In collaboration with the Laboratorio Analisi Scientifiche of Regione Autonoma Valle d'Aosta, the National Institute of Metrological Research and the Department of Architecture and Design of the Polytechnic of Turin, we created a scientific database that is now available online () designed as a tool for heritage science and conservation. Here, we present a focus on materials for pictorial retouching where the hyperspectral imaging application, conducted with a prototype of new technology, allowed to provide a list of pigments that could be more suitable for conservation treatments and pictorial retouching. Then we present the case study of the industrial painting Notte Barbara (1962) by Pinot Gallizio where the use of the database including modern and contemporary art materials showed to be very useful and where the fibre optics reflectance spectroscopy technique was decisive for pigment identification purpose. Later in this research, the mock-ups will be exploited to study degradation processes, e.g., the lightfastness, or the possible formation of interaction products, e.g., metal carboxylates. [ABSTRACT FROM AUTHOR]

LaW x Nb 1−x O 4+x/2 ceramics (x = 0.16) were prepared via a solid state route and studied with respect to phase stability and mixed ionic and electronic conductivity under conditions of technological relevance for fuel cell applications. The chemical compatibility against standard cathode materials revealed that Sr-doped LaMnO 3 could be used without detectable chemical interaction up to at least 1000 °C. Impedance spectroscopy measurements performed in the range 400–850 °C, using different atmospheres (air and N 2 +H 2 , both dry and water vapour saturated), suggest oxygen transport numbers equal to 1 under oxidising conditions, and decreasing when exposed to extreme reducing conditions. The total conductivity at 800 °C increases from 1.4·10 −3 S cm −1 in air to 2.5·10 −3 S cm −1 in wet hydrogen and 6.1·10 −3 S cm −1 in dry hydrogen, but the observed onset of n-type conductivity has little practical impact under typical fuel cell operating conditions. [ABSTRACT FROM AUTHOR]

Particle stabilized liquid foams are used as templates to obtain carbon-based porous materials with open cell structure, high specific area and hierarchical porosity. This route relies on gel casting to strengthen the structure of the liquid foams, followed by high temperature treatment to eliminate organic components and obtain solid foams. The liquid foam stabilizer was a commercial activated carbon powder, characterized by high porosity and irregular morphology of the particles, associated with a cationic surfactant. The micro-structure and the textural properties of the final solid materials have been investigated by Scanning Electronic Microscopy and Nitrogen adsorption methods. The results show that this method can be used to fabricate high specific area porous materials in the form of monoliths, with adequate consistence and mechanical resistance. The materials obtained seem promising for many practical applications such as gas adsorption, filtering and catalysis. [ABSTRACT FROM AUTHOR]

In this research, we pretend to account for the causes or motivations that lead different subjects to commit crimes as they tell in their own life stories. These subjects live in street situations and were interviewed during the years 2003 to 2011 in the city of Buenos Aires. We start from a multidisciplinary perspective between psychoanalysis and linguistics. We are interested in life stories as a particular form of orality, which also allow us to analyze, explain and interpret examples of how these subjects relate to guilt. One of the forms found is that of those who before the crime feel guilty. The second is that of those who feel no guilt about the crime. And the third is that of those who do not feel it. We also emphasize social inequality as the cause of crime. We analyze linguistically the hierarchy of information, especially the focus of emissions. The theoretical framework is the Discourse Analysis and the methodology is qualitative. [ABSTRACT FROM AUTHOR]

A gunflint is a piece of rock used to activate firearms by producing a spark and the subsequent ignition of gunpowder to fire a projectile. Originated in Europe, this technology was developed and used between the 17th and 19th centuries. Since the study of this technology is at an early stage in Argentinian archaeology, the main goal of this paper is to present a review of the available data on the subject. Thus, aspects of the gunflints' origins and circulation, the types of weapons in which they were used, the manufacturing techniques and raw materials used, the techno-typological attributes, the context of use and life cycle, and existing records up to date on gunflints recovered in archaeological contexts in Argentina, are presented and discussed. We expect that this review and synthesis paper works as a reference for the study of this "historic" technology among researchers interested and unfamiliar with it. [ABSTRACT FROM AUTHOR]

We report a case of simultaneous transcatheter aortic valve replacement and endovascular aneurysm repair. Our aim was to advocate the role of local and regional anesthesia as a key contributor in maintaining hemodynamic stability and avoiding abrupt blood pressure change. Endovascular combined procedures are gaining popularity for their numerous advantages. Nevertheless, they carry significant risks for their hemodynamic implications. It is imperative to acknowledge the modifications occurring after each correction and act accordingly. Different anesthesia approaches can dramatically influence hemodynamics; among all, we found local and regional anesthesia would better serve this objective. [ABSTRACT FROM AUTHOR]

One-dimensional nanostructures are usually fabricated using liquid-phase chemical methods or growth from the vapor phase. A different approach is proposed in this investigation. Using two different kinds of reactive templates with core−shell structure obtained using colloidal chemistry methods, we fabricated for the first time Bi4Ti3O12 nanorods and nanotubes by means of solid-state reactions. The intimate contact of the parent compounds in the core−shell template resulted in low reaction temperatures (500−600 °C), overcoming the morphological instability problem of one-dimensional (1D) templates. As the formation of bismuth titanate is dominated by the coupled ambipolar diffusion of Bi3+ and O2− ions through the titanate layer, the final morphology, nanorod or nanotube, is determined by the relative arrangement of the parent compounds in the core−shell template. When the bismuth precursor is located in the shell region and the core is a single-crystal TiO2 nanowire, formation of a single-crystal Bi4Ti3O12 nanorod occurs by a topochemical reaction. Opposite, when the shell corresponds to nanocrystalline TiO2 and the core to the bismuth precursor, the reaction leads to a porous nanorod or a nanotube depending on the template thickness. The development of the central cavity is ascribed to the coalescence of Kirkendall porosity and the effect of mechanical stresses accumulated during the reaction. The present results indicate that a careful control of the solid-state reactions at the nanoscale can be achieved by means of reactive templates with core−shell structure thus providing an effective tool for the design and the large-scale fabrication of a variety of nano-objects with different dimensionalities. Careful control of the solid-state reactions at the nanoscale can be achieved by means of reactive templates with core−shell structure, thus providing an effective tool for the design and the large-scale fabrication of a variety of nano-objects with different dimensionalities. [ABSTRACT FROM AUTHOR]

Nanocoatings (5–20 nm) of different compounds on fine BaTiO3 particles were obtained by means of precipitation processes. Homogeneous and smooth shells of Y(OH)CO3 and Dy(OH)CO3 were grown from nitrate solutions in the presence of urea. An irregular coating consisting of zirconia nanoparticles was produced from zirconyl nitrate solution using ammonia as a precipitating agent after adsorption of a polymeric polyelectrolyte on the BaTiO3 surface. Composite particles with a peculiar morphology were obtained by inducing heterogeneous nucleation and growth of Ni(OH)2 lamellae on the BaTiO3 surface. The different shells can be transformed in a nanocrystalline coating of the corresponding oxide (Y2O3, Dy2O3, ZrO2, NiO) by calcination at moderate temperatures (400–700 °C). The overall results indicate that precipitation from solution represents a versatile process to grow a second-phase layer on the surface of BaTiO3 particles. This approach can be used as an alternative to mechanical wet mixing for controlled doping of ferroelectric materials and for the fabrication of composite materials with specific geometry of the two-phase assembly. [ABSTRACT FROM AUTHOR]

Abstract: Zinc oxide nanoparticles were produced by aqueous precipitation in mild hydrothermal conditions (90°C). Well crystallized regular roundish particles were obtained, with a very narrow size distribution. The influence of soft templates (organic species) to control size and size distribution in the final product was investigated. No effect was observed with polyvinylpyrrolidone (PVP M w 8000 and 40,000), (d−)fructose and hydroxypropylmethylcellulose (HPMC). A significant decrease of the particle size towards 100nm, while conserving a very narrow size distribution was observed for poly(acrylic acid) (PAA M w 2000), Dispex A40 (commercial PAA from CIBA M w ∼10,000), and sodium dodecylsulfate (SDS). The influence of the pH was also investigated with PAA. By increasing the pH from slightly acidic to basic conditions, the morphology was spectacularly modified from roundish nanoparticles to micronic branched flower-like particles, with an elongated primary crystal morphology. [Copyright &y& Elsevier]

Due to the high permittivity and low losses, ferroelectric ceramics with perovskite structure are largely used in the electronics industry for many applications. Presently, miniaturization of the components is one of the main goal in the field of microelectronics and communication. Accordingly, the current trend in high-tech ceramics is to realize sintered bodies with grain size below a few hundred of nanometres. This aim can be attained using high-quality nanopowders (≈100 nm) with narrow particle size distribution (PSD), that allows low-temperature sintering at high densification and limited grain growth. Soft chemistry methods are presently receiving increasing interest. Ultra-fine, non-agglomerated BaTiO3 (BT) and SrTiO3 (ST) nanopowders with PSD were prepared considering the thermodynamic conditions for direct precipitation from the relevant metal chlorides in strong alkaline aqueous solution (T ≈ 45 ÷ 95 °C, P = 105 Pa, pH ≈ 14). Nuclei formation, crystallite growth and aggregation of crystallites were controlled to get high-quality powders. Strict control of supersaturation and temperature reduces the heterogeneity and allows a good control of cations concentration which determines the final particle size. Tailoring (15 ÷ 1500 nm) of BT, ST and other perovskites nanopowders with narrow PSD and good stoichiometry control was obtained. For high quality nanoceramics fast densification procedures are required to prevent grain growth. By Spark Plasma Sintering (SPS) high density nanocrystalline BT ceramics down to 30 nm at high density and excellent dielectric characteristics were obtained with interesting dielectric properties. Core-shell powders of various perovskite oxides were also prepared. [ABSTRACT FROM AUTHOR]

Abstract: Powders of BaY x Ce1− x O3− δ (x =0, 0.1 and 0.15) with specific surface area of 6–8 m2g−1 (BET equivalent particle size of 130–160 nm) were prepared by a modified solid-state route using nanocrystalline BaCO3 and CeO2 raw materials. These powders showed excellent densification at relatively low temperatures. Dense (96–97% relative density) ceramics with submicron grain size (0–4–0.6 µm) were obtained after sintering at 1250–1280 °C. Ceramics sintered at 1450 °C revealed only a moderate grain growth (grain size ≤2 µm), uniform microstructure and very high density (≥98%). The total conductivity of the submicron ceramics at 600 °C was comparable with the reference values reported in the literature, meaning that the high number of grain boundaries was not a limiting factor. On lowering temperature, the contribution of the blocking grain boundaries becomes progressively more important and the conductivity decreases in comparison to coarse-grained ceramics. Microscopic conductivities of grain interior and grain boundary are the same irrespective of grain size meaning that the different macroscopic behaviour is only determined by a geometric factor (a trivial size effect). [Copyright &y& Elsevier]

Polymers with different hydrophilic groups [polyvinylpyrrolidone (PVP), ammonium polyacrylate (APA), and hydroxypropylmethyl cellulose (HPMC)] and surfactants [cetyltrimethylammonium bromide (CTAB) and sodium dodecylbenzensulfonate (SDBS)] were used as additives to modify the crystallization of β-Ni(OH) 2in hydrothermal conditions. Marked morphological changes in the β-Ni(OH) 2particles were observed depending on the additive concentration and on the duration of the hydrothermal treatment. The final morphology is the result of a complex, time-dependent self-assembly and growth process. Well-defined particles with sizes from submicrometer range to a few micrometers corresponding to hexagonal lamellae, hexagonal tabular mesocrystals, rosette- and flowerlike aggregates of lamellae, hexagonal prismatic mesocrystals, and acicular nanocrystals were easily obtained after a short time (2−24 h) aging at 150−200 °C. With PVP and CTAB, there is evidence of a growth process dominated by self-assembly of nanocrystals to produce mesocrystals. The formation of spherical superstructures (with SDBS, up to 70 μm in diameter) and hollow spheres (with PVP) is observed at long times (>24 h) as a result of solvent-mediated recrystallization processes, like Ostwald ripening. The overall results show that hydrothermal synthesis of β-Ni(OH) 2in the presence of polymers with hydrophilic groups and surfactants is a versatile tool for crystal morphogenesis. [ABSTRACT FROM AUTHOR]

The formation of BaTiO3 nanoparticles by a solid-state reaction between nanocrystalline raw materials BaCO3 and TiO2 was studied as a function of temperature (400°–800°C), time (1–24 h), and titania particle size (15 and 30 nm). The reaction starts at 500°C and a high reaction rate is already observed at 600°C for the finest titania, with up to 90% conversion after 2 h. Two main reaction stages were observed at 600°–700°C. The first step is dominated by nucleation and growth of BaTiO3 at the TiO2–BaCO3 contact points and at the TiO2 surface. Surface diffusion of BaCO3 is, most likely, the prevailing mass transport mechanism responsible for the rapid formation of BaTiO3, even in the absence of a significant contribution from lattice diffusion. The second stage begins when the residual TiO2 cores are completely covered by the product phase. For longer times, the reaction can only proceed by the slower lattice diffusion, resulting in a strong decrease of the reaction rate. Single-phase BaTiO3 nanopowders with a specific surface area of 12–15 m2/g, an average particle size of 70–85 nm, a relative density of 96.5%–98.3%, and a tetragonality of 1.005 were obtained by calcination at 700°–800°C. Critical parameters in the preparation of ultrafine powders by solid-state reactions are the particle size of both raw materials, the absence of large hard agglomerates, and the homogeneity of the mixture. The use of fine raw materials and optimization of the reaction conditions make mechanical activation unnecessary. [ABSTRACT FROM AUTHOR]

Abstract: Di-phase ceramic composites 0.50BaTiO3–0.50Ni0.5Zn0.5Fe2O4 with limited reaction at interfaces prepared by two methods: (i) mixing BaTiO3 and Ni0.5Zn0.5Fe2O4 powders and (ii) co-precipitation of Fe, Ni, Zn salts in solutions containing BaTiO3 powders, are comparatively analysed. Homogeneous microstructures with higher density and better mixing of the two phases are obtained by the second method and consequently, better dielectric properties (tan δ <5% and ɛ r ∈300–800 for f >104 Hz at room temperature) and higher magnetic moments. Some interface effects are playing important roles on the dielectric properties at low frequencies and high temperatures, mainly in the samples prepared following the method (i). Both the ferroelectric and magnetic phases preserve their basic properties in the bulk composite form and thus, these composites BT-NZF are good candidates as magnetoelectric materials. [Copyright &y& Elsevier]