46 research outputs found

    First steps to define murine amniotic fluid stem cell microenvironment

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    Stem cell niche refers to the microenvironment where stem cells reside in living organisms. Several elements define the niche and regulate stem cell characteristics, such as stromal support cells, gap junctions, soluble factors, extracellular matrix proteins, blood vessels and neural inputs. In the last years, different studies demonstrated the presence of cKit+ cells in human and murine amniotic fluid, which have been defined as amniotic fluid stem (AFS) cells. Firstly, we characterized the murine cKit+ cells present both in the amniotic fluid and in the amnion. Secondly, to analyze the AFS cell microenvironment, we injected murine YFP+ embryonic stem cells (ESC) into the amniotic fluid of E13.5 wild type embryos. Four days after transplantation we found that YFP+ sorted cells maintained the expression of pluripotency markers and that ESC adherent to the amnion were more similar to original ESC in respect to those isolated from the amniotic fluid. Moreover, cytokines evaluation and oxygen concentration analysis revealed in this microenvironment the presence of factors that are considered key regulators in stem cell niches. This is the first indication that AFS cells reside in a microenvironment that possess specific characteristics able to maintain stemness of resident and exogenous stem cells

    Acoustic and relaxation processes in supercooled o-ter-phenyl by optical-heterodyne transient grating experiment

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    The dynamics of the fragile glass-forming o-ter-phenyl is investigated by time-resolved transient grating experiment with an heterodyne detection technique in a wide temperature range. We investigated the dynamics processes of this glass-former over more then 6 decades in time with an excellent signal/noise. Acoustic, structural and thermal relaxations have been clearly identify and measured in a time-frequency window not covered by previous spectroscopic investigations. A detailed comparison with the density response function, calculated on the basis of generalized hydrodynamics model, has been worked out

    Non-Equilibrium Thermodynamic Description of the Coupling between Structural and Entropic Modes in Supercooled Liquids

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    The density response of supercooled glycerol to an impulsive stimulated thermal grating (q=0.63 micron^-1) has been studied in the temperature range (T=200-340 K) where the structure rearrangement (alpha-relaxation) and thermal diffusion occur on the same time scale. A strong interaction between the two modes occurs giving rise to a dip in the T-dependence of the apparent thermal conductivity and a flattening of the apparent alpha-relaxation time upon cooling. A non-equilibrium thermodynamic (NET) model for the long time response of relaxing fluids has been developed. The model is capable to reproduce the experimental data and to explain the observed phenomenology.Comment: to be published in PRE Rapid Commu

    Solvent contribution to the stability of a physical gel characterized by quasi-elastic neutron scattering

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    The dynamics of a physical gel, namely the Low Molecular Mass Organic Gelator {\textit Methyl-4,6-O-benzylidene-α\alpha -D-mannopyranoside (α\alpha-manno)} in water and toluene are probed by neutron scattering. Using high gelator concentrations, we were able to determine, on a timescale from a few ps to 1 ns, the number of solvent molecules that are immobilised by the rigid network formed by the gelators. We found that only few toluene molecules per gelator participate to the network which is formed by hydrogen bonding between the gelators' sugar moieties. In water, however, the interactions leading to the gel formations are weaker, involving dipolar, hydrophobic or ππ\pi-\pi interactions and hydrogen bonds are formed between the gelators and the surrounding water. Therefore, around 10 to 14 water molecules per gelator are immobilised by the presence of the network. This study shows that neutron scattering can give valuable information about the behaviour of solvent confined in a molecular gel.Comment: Langmuir (2015

    Overview of the FTU results

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    Since the 2018 IAEA FEC Conference, FTU operations have been devoted to several experiments covering a large range of topics, from the investigation of the behaviour of a liquid tin limiter to the runaway electrons mitigation and control and to the stabilization of tearing modes by electron cyclotron heating and by pellet injection. Other experiments have involved the spectroscopy of heavy metal ions, the electron density peaking in helium doped plasmas, the electron cyclotron assisted start-up and the electron temperature measurements in high temperature plasmas. The effectiveness of the laser induced breakdown spectroscopy system has been demonstrated and the new capabilities of the runaway electron imaging spectrometry system for in-flight runaways studies have been explored. Finally, a high resolution saddle coil array for MHD analysis and UV and SXR diamond detectors have been successfully tested on different plasma scenarios

    Запозичення як фактор розвитку базових концептів англійської мови (на прикладі концепту dwelling)

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    Розвиток лексичної та концептуальної систем англійської мови в значній мірі визначається роллю запозиченого матеріалу. Особливий інтерес становить трансформація цих систем в давньоанглійський період, який характеризується використанням запозичених одиниць на мовному рівні та зіткненням двох етносів, отже, двох концептуальних світів – на культурологічному і когнітивному. Об’єктом дослідження статті є базовий концепт антропології повсякденності dwelling, що відображує як загально-специфічні, так і культурно-специфічні особливості етносу, що запозичує.Развитие лексической и концептуальной систем английского языка во многом определяется ролью заимствованного материала. Особый интерес представляет собой трансформация данных систем в древнеанглийский период, характеризующийся использованием заимствованных единиц на языковом уровне и столкновением двух этносов, следовательно, двух концептуальных миров – на культурологическом и когнитивном. Объектом исследования в данной статье является базовый концепт антропологии повседневности dwelling, отражающий как обще-специфичные, так и культурноспецифичные особенности заимствующего этноса.The development of the English language lexical and conceptual systems is determined by the role of the borrowed material. The particular interest lies in the transformation of these systems in the old English period that is characterized by the usage of the borrowed units on the lexical level and by the interaction of two ethnoses, i.e. two conceptual worlds – on the cultural and cognitive levels. The object of the investigation in the given article is represented by the basic concept of everyday anthropology ‘dwelling’, reflecting both generally specific and culturally specific peculiarities of the borrowing ethnos

    A THz Scanner to Detect Moisture on Wood Samples

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    Wood is a hygroscopic material that is subject to phenomena of water exchange with the external environment. These exchanges can cause dimensional variations and cracks to appear on a macroscopic level. In recent years, the use of terahertz technologies in the field of diagnostics applied to cultural heritage has increased considerably. One of the most important characteristics of terahertz radiation is its sensitivity to water content; this polar liquid strongly absorbs and reflects this radiation. The subject of this study will be the detection of moisture in pine wood samples using a 97 GHz terahertz imaging system

    Selecting hazelnuts by coupling a self-organizing map (SOM) and an experimental system operating in transmission configuration

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    An experimental setup operating in transmission mode in the frequency range between 18 and 40 GHz is described. This study shows how the system is able to distinguish healthy and rotten hazelnuts. In addition, a Self-Organizing Map (SOM) trained with the Kohonen algorithm was used to classify the hazelnuts according to their quality

    THz Data Analysis and Self-Organizing Map (SOM) for the Quality Assessment of Hazelnuts

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    In recent years, the use of techniques based on electromagnetic radiation as an investigative tool in the agri-food industry has grown considerably, and between them, the application of imaging and THz spectroscopy has gained significance in the field of food quality control. This study presents the development of an experimental setup operating in transmission mode within the frequency range of 18 to 40 GHz, which was specifically designed for assessing various quality parameters of hazelnuts. The THz measurements were conducted to distinguish between healthy and rotten hazelnut samples. Two different data analysis techniques were employed and compared: a traditional approach based on data matrix manipulation and curve fitting for parameter extrapolation, and the utilization of a Self-Organizing Map (SOM), for which we use a neural network commonly known as the Kohonen neural network, which is recognized for its efficacy in analyzing THz measurement data. The classification of hazelnuts based on their quality was performed using these techniques. The results obtained from the comparative analysis of coding efforts, analysis times, and outcomes shed light on the potential applications of each method. The findings demonstrate that THz spectroscopy is an effective technique for quality assessment in hazelnuts, and this research serves to clarify the suitability of each analysis technique
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