205 research outputs found

    Shrinkage and mitigation strategies to improve the dimensional stability of CaO-FeOx-Al2O3-SiO2 inorganic polymers

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    Volumetric stability is an important aspect of the performance of building materials, and the shrinkage of CaO-FeOx-Al2O3-SiO2-rich inorganic polymers (IPs) has not been thoroughly investigated yet. Hence, this paper describes the outcome of a study conducted to investigate ways to minimize their shrinkage using different curing regimes. Two different slags were used as case studies to assess the robustness of the developed mitigation strategies. IP pastes and mortars were cured at (i) room condition, (ii) in slightly elevated temperature (60 \ub0C for 2 d) and (iii) in a water-saturated environment. The reaction kinetics and formed products were examined on IP pastes, while mortars were made to characterize the 28 d pore structure, autogenous shrinkage, drying shrinkage, and strength development. The results showed that the precursors\u2019 reactivity and curing conditions severely affect shrinkage mechanisms and magnitude. Volumetric changes in the plastic stage can be related to the precursors\u2019 reactivity but drying shrinkage was the driving mechanism affecting the volumetric stability of all IP mortars. Understanding the effect of a precursor\u2019s composition and curing conditions on shrinkage is fundamental to develop proper mitigation strategies and to overcome one of IPs\u2019 main technical drawbacks

    Pheophorbide a identified in an Eupatorium perfoliatum extract is a novel lymphatic vascular activator

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    The lymphatic vascular system is crucial for maintaining tissue fluid homeostasis and immune surveillance. Promoting lymphatic function represents a new strategy to treat several diseases including lymphedema, chronic inflammation and impaired wound healing. By screening a plant extract library, a petroleum ether extract from the aerial parts of Eupatorium perfoliatum (E. perfoliatum) was found to possess lymphangiogenic properties. With the aid of HPLC activity profiling the active compound was identified as pheophorbide a. Both plant extract and pheophorbide a induced the sprouting and tube formation of human primary lymphatic endothelial cells (LECs). The proliferation of the LECs was increased upon treatment with pheophorbide a but not the E. perfoliatum extract. Treatment with the MEK1/2 inhibitor U0126 reduced the LEC sprouting activity, indicating a potential mechanism of action. These studies suggest that pheophorbide a could represent novel natural therapeutic agent to treat human lymphatic vascular insufficiencies

    Identification of plant-derived alkaloids with therapeutic potential for myotonic dystrophy type I

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    Myotonic dystrophy type I (DM1) is a disabling neuromuscular disease with no causal treatment available. This disease is caused by expanded CTG trinucleotide repeats in the 3 UTR of the dystrophia myotonica protein kinase gene. On the RNA level, expanded (CUG)n repeats form hairpin structures that sequester splicing factors such as muscleblind-like 1 (MBNL1). Lack of availableMBNL1leads to misregulated alternative splicing of many target pre-mRNAs, leading to the multisystemic symptoms in DM1. Many studies aiming to identify small molecules that target the (CUG)n-MBNL1 complex focused on synthetic molecules. In an effort to identify new small molecules that liberate sequesteredMBNL1from (CUG)n RNA, we focused specifically on small molecules of natural origin. Natural products remain an important source for drugs and play a significant role in providing novel leads and pharmacophores for medicinal chemistry. In a new DM1 mechanism-based biochemical assay, we screened a collection of isolated natural compounds and a library of over 2100 extracts from plants and fungal strains. HPLC-based activity profiling in combination with spectroscopic methods were used to identify the active principles in the extracts. The bioactivity of the identified compounds was investigated in a human cell model and in a mouse model of DM1.We identified several alkaloids, including the -carboline harmine and the isoquinoline berberine, that ameliorated certain aspects of theDM1pathology in these models. Alkaloids as a compound class may have potential for drug discovery in other RNA-mediated diseases

    Placental determinants of fetal growth: identification of key factors in the insulin-like growth factor and cytokine systems using artificial neural networks

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    <p>Abstract</p> <p>Background</p> <p>Changes and relationships of components of the cytokine and IGF systems have been shown in placenta and cord serum of fetal growth restricted (FGR) compared with normal newborns (AGA). This study aimed to analyse a data set of clinical and biochemical data in FGR and AGA newborns to assess if a mathematical model existed and was capable of identifying these two different conditions in order to identify the variables which had a mathematically consistent biological relevance to fetal growth.</p> <p>Methods</p> <p>Whole villous tissue was collected at birth from FGR (N = 20) and AGA neonates (N = 28). Total RNA was extracted, reverse transcribed and then real-time quantitative (TaqMan) RT-PCR was performed to quantify cDNA for IGF-I, IGF-II, IGFBP-1, IGFBP-2 and IL-6. The corresponding proteins with TNF-α in addition were assayed in placental lysates using specific kits. The data were analysed using Artificial Neural Networks (supervised networks), and principal component analysis and connectivity map.</p> <p>Results</p> <p>The IGF system and IL-6 allowed to predict FGR in approximately 92% of the cases and AGA in 85% of the cases with a low number of errors. IGF-II, IGFBP-2, and IL-6 content in the placental lysates were the most important factors connected with FGR. The condition of being FGR was connected mainly with the IGF-II placental content, and the latter with IL-6 and IGFBP-2 concentrations in placental lysates.</p> <p>Conclusion</p> <p>These results suggest that further research in humans should focus on these biochemical data. Furthermore, this study offered a critical revision of previous studies. The understanding of this system biology is relevant to the development of future therapeutical interventions possibly aiming at reducing IL-6 and IGFBP-2 concentrations preserving IGF bioactivity in both placenta and fetus.</p

    Environmental Performance Indicators for Roadway and Highway Infrastructures Management

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    This work reviews the main performance indicators (PIs) currently used in literature to assess the environmental-related impacts for the phases of construction and quality control and management of infrastructures, with special attention to those applied on roadways and highways. Particularly, the adoption of such non-technical PIs may have a significant impact on decision-making processes to define both constructive choices, and also managing and maintanance protocols. Among the analysed PIs, on one hand, simplified indicators, such as those based on simplified mass balance functions, are suitable to quickly highlight if recycling/reuse strategies are adopted. On the other hand, those derived through a Life Cycle Assessment (LCA) are worth to be mentioned, due to their ability of capturing the whole impacts within defined system boundaries during the life-cycle of the infrastructure. Such impacts can also be translated into costs, indicating the economic value loss caused by the degradation of the environmental indicators
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