59 research outputs found

    Quantifying cancer epithelial-mesenchymal plasticity and its association with stemness and immune response

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    Cancer cells can acquire a spectrum of stable hybrid epithelial/mesenchymal (E/M) states during epithelial-mesenchymal transition (EMT). Cells in these hybrid E/M phenotypes often combine epithelial and mesenchymal features and tend to migrate collectively commonly as small clusters. Such collectively migrating cancer cells play a pivotal role in seeding metastases and their presence in cancer patients indicates an adverse prognostic factor. Moreover, cancer cells in hybrid E/M phenotypes tend to be more associated with stemness which endows them with tumor-initiation ability and therapy resistance. Most recently, cells undergoing EMT have been shown to promote immune suppression for better survival. A systematic understanding of the emergence of hybrid E/M phenotypes and the connection of EMT with stemness and immune suppression would contribute to more effective therapeutic strategies. In this review, we first discuss recent efforts combining theoretical and experimental approaches to elucidate mechanisms underlying EMT multi-stability (i.e. the existence of multiple stable phenotypes during EMT) and the properties of hybrid E/M phenotypes. Following we discuss non-cell-autonomous regulation of EMT by cell cooperation and extracellular matrix. Afterwards, we discuss various metrics that can be used to quantify EMT spectrum. We further describe possible mechanisms underlying the formation of clusters of circulating tumor cells. Last but not least, we summarize recent systems biology analysis of the role of EMT in the acquisition of stemness and immune suppression.Comment: 50 pages, 6 figure

    Izdvajanje dihidromiricetina iz lišća biljke Ampelopsis grossedentata mikrovalnom i višefaznom protustrujnom ekstrakcijom

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    Microwave-assisted extraction (MAE) technique in combination with multi-stage countercurrent extraction (MCE), namely microwave multi-stage countercurrent extraction (MMCE), was evaluated for the extraction of dihydromyricetin (DMY) from Ampelopsis grossedentata. Ethanol, methanol and water were used as extract solvents in the MMCE method. Of the three solvents used, water was found to be the best in extracting DMY from Ampelopsis grossedentata because it had a good extraction yield and is inexpensive, non-toxic and environmentally friendly. The optimal conditions of MMCE for the extraction of DMY can be determined to be the ratio of the extraction solvent to plant material of 30:1, the extraction time of 5 min, the extraction temperature of 110 °C and the microwave power of 600 W. In addition, the extraction efficiency of the MMCE method was compared with that of the microwave static batch extraction (MSBE) under the optimum extraction conditions. It was found that the MMCE method offered higher extraction efficiency than the MSBE method. Thus, the study suggests that the MMCE method provides an alternative technique in terms of both cost and efficiency.Ekstrakcija dihidromiricetina iz lišća biljke Ampelopsis grossedentata pokusno je provedena metodom mikrovalne ekstrakcije u kombinaciji s višefaznom protustrujnom ekstrakcijom. Kao otapalo upotrijebljeni su etanol, metanol i voda. Voda je najbolja za ekstrakciju dihidromiricetina iz Ampelopsis grossedentata jer daje dobro iskorištenje, jeftina je, nije toksična i ekološki je prihvatljiva. Kao optimalni uvjeti ovako kombinirane metode za ekstrakciju dihidromiricetina određeni su: omjer otapala i biljnog materijala 30:1, vrijeme ekstrakcije od 5 min, temperatura od 110 °C i snaga mikrovalova od 600 W. Uspoređujući učinkovitost ove metode s metodom diskontinuirane mikrovalne ekstrakcije u optimalnim uvjetima, vidi se da se veća učinkovitost ekstrakcije postiže višefaznom nego diskontinuiranom mikrovalnom ekstrakcijom. Stoga se, s obzirom na troškove i njezinu učinkovitost, može preporučiti kao alternativna metoda

    Frequency characteristic analysis on acoustic emission of mortar using cement-based piezoelectric sensors

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    Acoustic emission (AE) monitoring was conducted for mortar specimens under three types of static loading patterns (cubic-splitting, direct-shear and pull-out). Each of the applied loading patterns was expected to produce a particular fracture process. Subsequently, the AEs generated by various fracture or damage processes carried specific information on temporal micro-crack behaviors of concrete for post analysis, which was represented in the form of detected AE signal characteristics. Among various available characteristics of acquired AE signals, frequency content was of great interest. In this study, cement-based piezoelectric sensor (as AE transducer) and home-programmed DEcLIN monitoring system were utilized for AE monitoring on mortar. The cement-based piezoelectric sensor demonstrated enhanced sensitivity and broad frequency domain response range after being embedded into mortar specimens. This broad band characteristic of cement-based piezoelectric sensor in frequency domain response benefited the analysis of frequency content of AE. Various evaluation methods were introduced and employed to clarify the variation characteristics of AE frequency content in each test. It was found that the variation behaviors of AE frequency content exhibited a close relationship with the applied loading processes during the tests

    Ultrasonic Monitoring of the Early-Age Hydration of Mineral Admixtures Incorporated Concrete using Cement-Based Piezoelectric Composite Sensors

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    The early-age hydration processes of concretes with mineral admixtures have been monitored and evaluated by a newly developed ultrasonic method based on embedded cement-based piezoelectric composite sensors. With the embedded ultrasonic (P-wave) measurement system, the waveform, wave velocity, attenuation coefficient index, and frequency-domain spectrum of detected ultrasonic waves during hydration can be recorded. The mineral admixtures examined include fly ash, slag, and silica fume, which replace part of the cement in concrete mixtures. It is found that the ultrasonic transmission parameters can be related to the microstructure changes of the concrete. Both the acceleration effects of silica fume and the retardation effects of fly ash and slag on the early hydration of concrete can be determined and explained through the analysis and comparison of the characteristics of the velocity curves. The attenuation coefficient index curve provides additional observation for the study of hydration kinetics. Moreover, the function of fresh concrete in filtering the high-frequency component of the wave varies with time, and concrete can be considered as low-pass frequency spectral filter. Frequency spectra analysis at different ages of fresh concrete provides useful information to reveal the early-age hydration process

    Signal-Based Acoustic Emission Monitoring on Mortar Using Cement-Based Piezoelectric Sensors

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    Signal-based acoustic emission (AE) monitoring on mortar was performed under three types of static loading patterns: cubic-splitting, direct-shear, and pullout. Each of the applied loading patterns was expected to produce a distinguished fracture process on mortar. This study was the first to combine a cement-based piezoelectric sensor (such as an AE transducer) and a home-programmed DEcLIN monitoring system for monitoring the concrete fracture process in mortar It was found that the cement-based piezoelectric sensor has much better sensitivity and a much broader frequency domain response range as compared to traditional piezoelectric ceramic transducers after embedding into mortar specimens. The three-dimensional (3-D) localization of AE sources and the signal-based AE energy index obtained by the DEcLIN system were used to vividly explain and quantitatively evaluate the fracture processes of mortar specimens under various types of loadings. It was revealed that the fracture processes in mortar under the cubic-splitting and direct-shear loading patterns were evidently more brittle than that of the pullout test

    Signal-based AE characterization of concrete with cement-based piezoelectric composite sensors

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    The signal-based acoustic emission (AE) characterization of concrete fracture process utilizing home-programmed AE monitoring system was performed for three kinds of static loading tests (Cubic-splitting, Direct-shear and Pull-out). Each test was carried out to induce a distinct fracture mode of concrete. Apart from monitoring and recording the corresponding fracture process of concrete, various methods were utilized to distinguish the characteristics of detected AE waveform to interpret the information of fracture behavior of AE sources (i.e. micro-cracks of concrete). Further, more signal-based characters of AE in different stages were analyzed and compared in this study. This research focused on the relationship between AE signal characteristics and fracture processes of concrete. Thereafter, the mode of concrete fracture could be represented in terms of AE signal characteristics. By using cement-based piezoelectric composite sensors, the AE signals could be detected and collected with better sensitivity and minimized waveform distortion, which made the characterization of AE during concrete fracture process feasible. The continuous wavelet analysis technique was employed to analyze the wave-front of AE and figure out the frequency region of the P-wave & S-wave. Defined RA (rising amplitude), AF (average frequency) and P-wave & S-wave importance index were also introduced to study the characters of AE from concrete fracture. It was found that the characters of AE signals detected during monitoring could be used as an indication of the cracking behavior of concrete

    Modeling Magnesia-Phosphate Cement Paste at the Micro-Scale

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    In this paper, a computer model is established to simulate the microstructure of magnesia-phosphate cement paste at the micro-scale. The chemical reaction in the paste is analyzed first, based on which the microstructure is modeled through interacted growing and eroding spherical particles representing the solid phases. The pore structure of the simulated paste is characterized by a closing operation based algorithm. It is found that the simulated pore size distribution curves are consistent with corresponding experimental results

    Study of the Impact of Initial Moisture Content in Oil Impregnated Insulation Paper on Thermal Aging Rate of Condenser Bushing

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    This paper studied the impact of moisture on the correlated characteristics of the condenser bushings oil-paper insulation system. The oil-impregnated paper samples underwent accelerated thermal aging at 130 °C after preparation at different initial moisture contents (1%, 3%, 5% and 7%). All the samples were extracted periodically for the measurement of the moisture content, the degree of polymerization (DP) and frequency domain dielectric spectroscopy (FDS). Next, the measurement results of samples were compared to the related research results of transformer oil-paper insulation, offering a theoretical basis of the parameter analysis. The obtained results show that the moisture fluctuation amplitude can reflect the different initial moisture contents of insulating paper and the mass ratio of oil and paper has little impact on the moisture content fluctuation pattern in oil-paper but has a great impact on moisture fluctuation amplitude; reduction of DP presents an accelerating trend with the increase of initial moisture content, and the aging rate of test samples is higher under low moisture content but lower under high moisture content compared to the insulation paper in transformers. Two obvious “deceleration zones” appeared in the dielectric spectrum with the decrease of frequency, and not only does the integral value of dielectric dissipation factor (tan δ) reflect the aging degree, but it reflects the moisture content in solid insulation. These types of research in this paper can be applied to evaluate the condition of humidified insulation and the aging state of solid insulation for condenser bushings
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