2,396 research outputs found
The effects of MgO, Na2O and SO3 on industrial clinkering process: phase composition, polymorphism, microstructure and hydration, using a multidisciplinary approach
Preprint publicado en: Materials Characterization Volume 155, September 2019, 109809The present investigation deals with how minor elements (their oxides: MgO, Na2O and SO3) in industrial kiln
feeds affect (i) chemical reactions upon clinkering, (ii) resulting phase composition and microstructure of
clinker, (iii) hydration process during cement production.
Our results show that all these points are remarkably sensitive to the combination and interference effects
between the minor chemical species mentioned above.
Upon clinkering, all the industrial raw meals here used exhibit the same formation temperature and amount
of liquid phase. Minor elements are preferentially hosted by secondary phases, such as periclase. Conversely, the
growth rate of the main clinker phases (alite and belite) is significantly affected by the nature and combination
of minor oxides. MgO and Na2O give a very fast C3S formation rate at T > 1450 K, whereas Na2O and SO3 boost
C2S
After heating, if SO3 occurs in combination with MgO and/or Na2O, it does not inihibit the C3S crystallisation
as expected. Rather, it promotes the stabilisation of M1-C3S, thus indirectly influencing the aluminate content,
too. MgO increseases the C3S amount and promotes the stabilisation of M3-C3S, when it is in combination with
Na2O. Na2O seems to be mainly hosted by calcium aluminate structure, but it does not induce the stabilisation of
the orhtorhombic polymorph, as supposed to occur. Such features play a key role in predicting the physicalmechanical
performance of a final cement (i.e. rate of hydration and hardening) when used as a bulding material.The present study has been partly funded by the project PRIN 2017
(2017L83S77), of the Italian Ministry for Education, University and
Research (MIUR)
Bone-Resorbing Cells in Multiple Myeloma: Osteoclasts, Myeloma Cell Polykaryons, or Both?
Abstract
Myeloma bone disease (MBD) leads to progressive destruction of the skeleton and is the most severe cause of morbidity in multiple myeloma. Its pathogenetic mechanisms are not fully understood, though the current evidence points to osteoclast (OC) hyperactivity coupled with defective osteoblast function unable to counteract bone resorption. OCs are generated in bone marrow by myeloid progenitors through increased levels of receptor activator of nuclear factor ÎşB ligand and M-CSF, whose intracellular pathways propagate signals that activate sequential transcription factors, resulting in the production of major OC enzymes that drive specific functions such as acidification and degradation of the bone matrix. Osteolytic lesions, however, are not characterized by massive OC content, whereas malignant plasma cells, which are usually present in a high number, may occur as large multinucleated cells. The possibility that myeloma cells fuse and generate polykaryons in vivo is suggested by the in vitro formation of multinuclear cells that express tartrate-resistant acid phosphatase and produce pits and erosive lacunae on experimental osteologic substrates. Further, the detection in vivo of polykaryons with chromosome translocations typical of myeloma cells lends support to the view that myeloma polykaryons may act as functional OCs and participate in the skeletal destruction by resorbing bone
Learning Disability in RASopathies
Learning disabilities are relatively common conditions in pediatric population. The incidence of learning disability ranges from 1% to 17%, reflecting that learning disability may be not a single clinical entity but a wide distribution of cognitive traits in the population. As reported by the American Association on Intellectual and Developmental Disabilities (AAIDD), among the prenatal learning disability causes, chromosomal disorders, genetic syndromes, and inborn errors of metabolism must be taken into account. In this chapter, we will focus the attention on RASopathies, genetic disorders characterized by germline mutations in the RAS-MAPK pathway whose role is crucial in the regulation of the cell cycle, differentiation, growth, and cell senescence. This group of disorders includes Noonan syndrome, neurofibromatosis type 1, Costello syndrome (CS), Legius syndrome, Noonan syndrome with multiple lentigines, and cardiofaciocutaneous syndrome. Mutations in RAS-MAPK pathways lead to impairments in synaptic plasticity, necessary for normal brain function, especially for learning and memory. Variation across the RAS/MAPK pathway syndromes suggests that different gene mutations affecting this pathway can have markedly different developmental effects
Video-based Goniometer Applications for Measuring Knee Joint Angles during Walking in Neurological Patients: A Validity, Reliability and Usability Study
: Easy-to-use evaluation of Range Of Motion (ROM) during walking is necessary to make decisions during neurological rehabilitation programs and during follow-up visits in clinical and remote settings. This study discussed goniometer applications (DrGoniometer and Angles - Video Goniometer) that measure knee joint ROM during walking through smartphone cameras. The primary aim of the study is to test the inter-rater and intra-rater reliability of the collected measurements as well as their concurrent validity with an electro-goniometer. The secondary aim is to evaluate the usability of the two mobile applications. A total of 22 patients with Parkinson's disease (18 males, age 72 (8) years), 22 post-stroke patients (17 males, age 61 (13) years), and as many healthy volunteers (8 males, age 45 (5) years) underwent knee joint ROM evaluations during walking. Clinicians and inexperienced examiners used the two mobile applications to calculate the ROM, and then rated their perceived usability through the System Usability Scale (SUS). Intraclass correlation coefficients (ICC) and correlation coefficients (corr) were calculated. Both applications showed good reliability (ICC > 0.69) and validity (corr > 0.61), and acceptable usability (SUS > 68). Smartphone-based video goniometers could be used to assess the knee ROM during walking in neurological patients, because of their acceptable degree of reliability, validity and usability
New calcium alkoxides for consolidation of carbonate rocks. Influence of precursors' characteristics on morphology, crystalline phase and consolidation effects
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Growth Hormone Axis in Skeletal Dysplasias
Introduction: Skeletal dysplasias, also termed as osteochondrodysplasias, are a large heterogeneous group of disorders characterized by abnormalities of bone or cartilage growth or texture. They occur due to genetic mutations and their phenotype continues to evolve throughout life. Reduced growth is a common feature
Production and characterization of CSSI003 (2961) human induced pluripotent stem cells (iPSCs) carrying a novel puntiform mutation in RAI1 gene, Causative of Smith–Magenis syndrome
Smith-Magenis syndrome (SMS) is a complex genetic disorder characterized by developmental delay, behavioural
problems and circadian rhythm dysregulation. About 90% of SMS cases are due to a 17p11.2 deletion containing
retinoic acid induced1 (RAI1) gene, 10% are due to heterozygousmutations affecting RAI1 coding region.
Little is known about RAI1 role
The reliability of gait parameters captured via instrumented walkways: a systematic review and meta-analysis
Introduction: Electronic pressure-sensitive walkways are commonly available solutions to quantitatively assess gait parameters for clinical and research purposes. Many studies have evaluated their measurement properties in different conditions with variable findings. In order to be informed about the current evidence of their reliability for optimal clinical and scientific decision making, this systematic review provided a quantitative synthesis of the test-retest reliability and minimal detectable change of the captured gait parameters across different test conditions (single and cognitive dual-task conditions) and population groups. Evidence acquisition: A literature search was conducted in PubMed, Embase, and Scopus until November 2021 to identify articles that examined the test-retest reliability properties of the gait parameters captured by pressure-sensitive walkways (gait speed, cadence, stride length and time, double support time, base of support) in adult healthy individuals or patients. The methodological quality was rated using the "Consensus-based standards for the selection of health measurement instruments" checklist. Data were meta-analyzed on intraclass correlation coefficient to examine the test-retest relative reliability. Quantitative synthesis was performed for absolute reliability, examined by the weighted average of minimal detectable change values. Evidence synthesis: A total of 44 studies were included in this systematic review. The methodological quality was adequate in half of the included studies. The main finding was that pressure-sensitive walkways are reliable tools for objective assessment of spatial and temporal gait parameters both in singleand cognitive dual-task conditions. Despite few exceptions, the review identified intraclass correlation coefficient higher than 0.75 and minimal detectable change lower than 30%, demonstrating satisfactory relative and absolute reliability in all examined populations (healthy adults, elderly, patients with cognitive impairment, spinocerebellar ataxia type 14, Huntington's disease, multiple sclerosis, Parkinson's disease, rheumatoid arthritis, spinal cord injury, stroke or vestibular dysfunction). Conclusions: Current evidence suggested that, despite different populations and testing protocols used in the included studies, the test-retest reliability of the examined gait parameters was acceptable under single and cognitive dual-task conditions. Further high-quality studies with powered sample sizes are needed to examine the reliability findings of the currently understudied and unexplored pathologies and test conditions
Avelumab in gastric cancer
Gastric cancer (GC) is the fifth most common malignancy and the third cause of cancer-related deaths worldwide. Currently, surgery and chemotherapy remain the main therapeutic options and the prognosis of the disease is still poor in the metastatic setting. Avelumab is a human IgG1 antibody directed against PD-L1 approved for Merkel cell carcinoma and urothelial carcinoma that could be useful also for the treatment of GC. This review describes the chemical structure, the pharmacologic properties and the current knowledge of the efficacy of avelumab in the treatment of GC from the data available on the first and later phase clinical trials. The ongoing studies testing this drug either alone or in combination with other drugs are also described
Fabrication and characterization of biomimetic hydroxyapatite thin films for bone implants by direct ablation of a biogenic source
Biomimetic bone apatite coatings were realized for the first time by the novel Ionized Jet Deposition technique. Bone coatings were deposited on titanium alloy substrates by pulsed electron ablation of deproteinized bovine bone shafts in order to resemble bone apatite as closely as possible. The composition, morphology and mechanical properties of the coatings were characterized by GI-XRD, FT-IR, SEM-EDS, AFM, contact angle measurements, micro-scratch and screw-insertion tests. Different post-treatment annealing conditions (from 350 °C to 425 °C) were investigated. Bone apatite coatings exhibited a nanostructured surface morphology and a composition closely resembling that of the deposition target (i.e. natural bone apatite), also regarding the presence of magnesium and sodium ions. Crystallinity and composition of the coatings were strongly influenced by annealing temperature and duration; in particular, upon annealing at 400 °C and above, a crystallinity similar to that of bone was achieved. Finally, adhesion to the titanium substrate and hydrophilicity were significantly enhanced upon annealing, all characteristics being known to have a strong positive impact on promoting host cells attachment, proliferation and differentiation
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