825 research outputs found
Use of Sawing Waste from Zeolitic Tuffs in the Manufacture of Ceramics
This paper investigates the thermal transformation of powders of volcanic tuffs that are used as building stones and aims at thermally transforming them into ceramics. The following positive indications concerning this thermal transformation were found: (1) the structural evolution which brings products similar to traditional ceramics, (2) the good ability to give rise to dense and compact final products, and (3) the good mechanical properties and the lovely appearance of the final products. Nevertheless, the high values of linear shrinkages recorded in this work seem to strongly hinder the thermal transformation of this powder-like waste into ceramics. However, mixing this by-product with other powder-like waste exhibiting higher-dimensional stability, such as those deriving from sawing of granites, appears proper
Inclusion of Experimental Information in First Principles Modeling of Materials
We propose a novel approach to model amorphous materials using a first
principles density functional method while simultaneously enforcing agreement
with selected experimental data. We illustrate our method with applications to
amorphous silicon and glassy GeSe. The structural, vibrational and
electronic properties of the models are found to be in agreement with
experimental results. The method is general and can be extended to other
complex materials.Comment: 11 pages, 8 PostScript figures, submitted to J. Phys.: Condens.
Matter in honor of Mike Thorpe's 60th birthda
Zeolite-feldspar epiclastic rocks as flux in ceramic tile manufacturing
Low-cost, naturally-occurring mixtures of feldspar and zeolite occurring in epiclastic rocks are promising substitutes for conventional quartz-feldspathic fluxes in ceramic bodies, since their fusibility and low hardness are expected to improve both grinding and sintering. Three epiclastic outcrops, with a different zeolite-to-feldspar ratio, were characterized (XRPD, fusibility) and tested in porcelain stoneware bodies; their behaviour during processing was appraised and compared with that of a reference. The addition of an epiclastic rock (20 wt.%), replacing rhyolite and aplite fluxes, brought about some significant advantages, mainly represented by better grindability, lower firing temperature with improved mechanical strength and lower porosity. Disadvantages concern increased slip viscosity, worse powder compressibility, resulting in larger firing shrinkage, and a darker colour of the tiles due to relatively high amounts of iron oxide
Decoding the Equine Genome: Lessons from ENCODE
The horse reference genome assemblies, EquCab2.0 and EquCab3.0, have enabled great advancements in the equine genomics field, from tools to novel discoveries. However, significant gaps of knowledge regarding genome function remain, hindering the study of complex traits in horses. In an effort to address these gaps and with inspiration from the Encyclopedia of DNA Elements (ENCODE) project, the equine Functional Annotation of Animal Genome (FAANG) initiative was proposed to bridge the gap between genome and gene expression, providing further insights into functional regulation within the horse genome. Three years after launching the initiative, the equine FAANG group has generated data from more than 400 experiments using over 50 tissues, targeting a variety of regulatory features of the equine genome. In this review, we examine how valuable lessons learned from the ENCODE project informed our decisions in the equine FAANG project. We report the current state of the equine FAANG project and discuss how FAANG can serve as a template for future expansion of functional annotation in the equine genome and be used as a reference for studies of complex traits in horse. A well-annotated reference functional atlas will also help advance equine genetics in the pan-genome and precision medicine era
A longitudinal study on the information needs and preferences of patients after an acute coronary syndrome
Background: Research has shown that the provision of pertinent health information to patients with cardiovascular disease is associated with better adherence to medical prescriptions, behavioral changes, and enhanced perception of control over the disease. Yet there is no clear knowledge on how to improve information pertinence. Identifying and meeting the information needs of patients and their preferences for sources of information is pivotal to developing patient-led services. This prospective, observational study was aimed at exploring the information needs and perceived relevance of different information sources for patients during the twenty-four months following an acute coronary syndrome. Methods: Two hundred and seventeen newly diagnosed patients with acute coronary syndrome were enrolled in the study. The patients were primarily men (83.41 %) with a mean age of 57.28 years (range 35-75; SD = 7.98). Patients' needs for information and the perceived relevance of information sources were evaluated between 2 and 8 weeks after hospitalization (baseline) and during three follow-ups at 6, 12 and 24 months after baseline. Repeated measures ANOVA, Bonferroni post hoc tests and Cochran's Q Test were performed to test differences in variables of interest over time. Results: Results showed a reduction in information needs, but this decrease was significant only for topics related to daily activities, behavioral habits, risk and complication. At baseline, the primary sources of information were specialists and general practitioners, followed by family members and information leaflets given by physicians. Relevance of other sources changed differently over time. Conclusion: The present longitudinal study is an original contribution to the investigation of changes in information needs and preferences for sources of information among patients who are diagnosed with acute coronary syndrome. One of the main results of this study is that information on self-disease management is perceived as a minor theme for patients even two years after the event. Knowledge on how patients' information needs and perceived relevance of information sources change over time could enhance the quality of chronic disease management, leading health-care systems to move toward more patient-tailored care
Butterflies as bioindicators of metal contamination
Anthropogenic trace metal contamination has significantly increased and has caused many hazardous consequences for the ecosystems and human health. The Terni basin valley (Central Italy) shows a heavy load of pollutants from industrial activities, while the characteristic orography structure of the valley favours air stagnation, thus limiting air pollution dispersal. The present study conducted in 2014 aimed to determine the concentration of ten metals in five species of butterflies at nine sites in the Terni valley along a 21-km-long transect, including both relatively pristine and industrial areas. At sites where soil contamination was high for a given metal, such as for chromium as in the case of site 4 (the closest to the steel plant) and for lead as in the case of site 2 (contaminated by a firing range), higher levels of contamination were observed in the tissues of butterflies. We found a correlation between soil contamination and the concentration of Cr, Al and Sr in the tissues of some species of butterflies. The sensitivity to contamination differed among the five species; in particular, Coenonympha pamphilus was generally the species that revealed the highest concentrations of all the ten trace metals at the sites closer to the industrial area. It is known that C. pamphilus is a sedentary species and that its host plants are the Poaceae, capable of accumulating high quantities of metals in their rhizosphere region, thus providing the link with soil contamination. Therefore, monitoring the metal concentration levels in butterflies might be a good indicator and a control tool of environmental quality, specifically in areas affected by high anthropogenic pollution loads linked to a specific source
ROTATIONAL-DYNAMICS OF SOLID C-70 - A NEUTRON-SCATTERING STUDY
PMID: 10011126PMID: 10011126 This work at the University of Sussex at supported by the Science and Engineering Research Council, U.K.PMID: 10011126 This work at the University of Sussex at supported by the Science and Engineering Research Council, U.K.PMID: 10011126 This work at the University of Sussex at supported by the Science and Engineering Research Council, U.K.We report the results of neutron-diffraction and low-energy neutron-inelastic-scattering experiments on high-purity solid C-70 between 10 and 640 K. Thermal hysteresis effects are found to accompany structural changes both on cooling and on heating. The observed diffuse scattering intensity does not change with temperature. At 10 K broad librational peaks are observed at 1.82(16) meV [full width at half maximum=1.8(5) meV]. The peaks soften and broaden further with increasing temperature. At and above room temperature, they collapse into a single quasielastic line. At 300 K, the diffusive reorientational motion appears to be somewhat anisotropic, becoming less so with increasing temperature. An isotropic rotational diffusion model, in which the motions of adjacent molecules are uncorrelated, describes well the results at 525 K. The temperature dependence of the rotational diffusion constants is consistent with a thermally activated process having an activation energy of 32(7) meV.This work at the University of Sussex at supported by the Science and Engineering Research Council, U.K
Dynamic Structure Factor of Liquid and Amorphous Ge From Ab Initio Simulations
We calculate the dynamic structure factor S(k,omega) of liquid Ge (l-Ge) at
temperature T = 1250 K, and of amorphous Ge (a-Ge) at T = 300 K, using ab
initio molecular dynamics. The electronic energy is computed using
density-functional theory, primarily in the generalized gradient approximation,
together with a plane wave representation of the wave functions and ultra-soft
pseudopotentials. We use a 64-atom cell with periodic boundary conditions, and
calculate averages over runs of up to 16 ps. The calculated liquid S(k,omega)
agrees qualitatively with that obtained by Hosokawa et al, using inelastic
X-ray scattering. In a-Ge, we find that the calculated S(k,omega) is in
qualitative agreement with that obtained experimentally by Maley et al. Our
results suggest that the ab initio approach is sufficient to allow approximate
calculations of S(k,omega) in both liquid and amorphous materials.Comment: 31 pages and 8 figures. Accepted for Phys. Rev.
Cytokine Profile in Striated Muscle Laminopathies: New Promising Biomarkers for Disease Prediction
Laminopathies are a wide and heterogeneous group of rare human diseases caused by mutations of the LMNA gene or related nuclear envelope genes. The variety of clinical phenotypes and the wide spectrum of histopathological changes among patients carrying an identical mutation in the LMNA gene make the prognostic process rather difficult, and classical genetic screens appear to have limited predictive value for disease development. The aim of this study was to evaluate whether a comprehensive profile of circulating cytokines may be a useful tool to differentiate and stratify disease subgroups, support clinical follow-ups and contribute to new therapeutic approaches. Serum levels of 51 pro- and anti-inflammatory molecules, including cytokines, chemokines and growth factors, were quantified by a Luminex multiple immune-assay in 53 patients with muscular laminopathy (Musc-LMNA), 10 with non-muscular laminopathy, 22 with other muscular disorders and in 35 healthy controls. Interleukin-17 (IL-17), granulocyte colony-stimulating factor (G-CSF) and transforming growth factor beta (TGF-β2) levels significantly discriminated Musc-LMNA from controls; interleukin-1β (IL-1β), interleukin-4 (IL-4) and interleukin-8 (IL-8) were differentially expressed in Musc-LMNA patients compared to those with non-muscular laminopathies, whereas IL-17 was significantly higher in Musc-LMNA patients with muscular and cardiac involvement. These findings support the hypothesis of a key role of the immune system in Musc-LMNA and emphasize the potential use of cytokines as biomarkers for these disorders
Anharmonicity, vibrational instability and Boson peak in glasses
We show that a {\em vibrational instability} of the spectrum of weakly
interacting quasi-local harmonic modes creates the maximum in the inelastic
scattering intensity in glasses, the Boson peak. The instability, limited by
anharmonicity, causes a complete reconstruction of the vibrational density of
states (DOS) below some frequency , proportional to the strength of
interaction. The DOS of the new {\em harmonic modes} is independent of the
actual value of the anharmonicity. It is a universal function of frequency
depending on a single parameter -- the Boson peak frequency, which
is a function of interaction strength. The excess of the DOS over the Debye
value is at low frequencies and linear in in the
interval . Our results are in an excellent
agreement with recent experimental studies.Comment: LaTeX, 8 pages, 6 figure
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