993 research outputs found
Distribution of user-perceived usefulness of four presentation styles of opinion summarization
In this study, four opinion summarization styles were compared under an experimental environment. Thirty four participants sorted thirty two cards into five usefulness categories. Every eight cards belong to one presentation style. It was found that the users spent the shortest time on cards in ânot at all usefulâ category. The time of viewing âextremely usefulâ cards was also shorter than that of âsomewhat usefulâ, âusefulâ, and âvery usefulâ cards. This result can be explained with the components of the usefulness categories. Tag clouds and Aspect oriented sentiments needed less time to view. They are the major styles in ânot at all usefulâ and âextremely usefulâ. Paragraph summaries and Group samples requested more time and they took at least 50% in âsomewhat usefulâ, âusefulâ, and âvery usefulâ. The findings are consistent with our previous results
Preparation of Microporous Carbon from Sargassum horneri by Hydrothermal Carbonization and KOH Activation for CO2 Capture
High-performance microporous activated carbon (AHC) for CO2 capture was prepared from an emerging marine pollutant, Sargassum horneri, via hydrothermal carbonization (HTC) and KOH activation. The as-synthesized carbon material was characterized by N2 sorption-desorption measurement, TGA, SEM, XRD, FTIR, and elemental analysis. Impressively, the activated carbon exhibited high specific surface area (1221âm2/g), narrow distributed micropores (âŒ0.50ânm), and a relatively high nitrogen content (3.56 wt.%), which endowed this carbon material high CO2 uptake of 101.7âmg/g at 30°C and 1âbar. Moreover, the carbon material showed highly stable CO2 adsorption capacity and easy regeneration over four adsorption-desorption cycles. Two kinetic models were employed in this work and found that the pseudo-first-order kinetic model (R2 = 0.99) provided the best description. In addition, the high CO2 uptake is mainly attributed to the presence of abundant narrow microporous. The macroporous structure of hydrochar (HC) played an important role in the production of microporous carbon with high adsorption properties. This work provides an efficient strategy for preparing microporous activated carbon from Sargassum horneri, and AHC is a promising candidate acting as an efficient CO2 adsorbent for further industrial application
Stimulated superconductivity at strong coupling
Stimulating a system with time dependent sources can enhance instabilities,
thus increasing the critical temperature at which the system transitions to
interesting low-temperature phases such as superconductivity or superfluidity.
After reviewing this phenomenon in non-equilibrium BCS theory (and its marginal
fermi liquid generalization) we analyze the effect in holographic
superconductors. We exhibit a simple regime in which the transition temperature
increases parametrically as we increase the frequency of the time-dependent
source.Comment: 19 pages, 2 figure. v3: Comments, references and one figure added.
Version to appear in JHE
Biological behaviors and proteomics analysis of hybrid cell line EAhy926 and its parent cell line A549
<p>Abstract</p> <p>Background</p> <p>It is well established that cancer cells can fuse with endothelial cells to form hybrid cells spontaneously, which facilitates cancer cells traversing the endothelial barrier to form metastases. However, up to now, little is known about the biologic characteristics of hybrid cells. Therefore, we investigate the malignant biologic behaviors and proteins expression of the hybrid cell line EAhy926 with its parent cell line A549.</p> <p>Methods</p> <p>Cell counting and flow cytometry assay were carried out to assess cell proliferation. The number of cells attached to the extracellular matrix (Matrigel) was measured by MTT assay for the adhesion ability of cells. Transwell chambers were established for detecting the ability of cell migration and invasion. Tumor xenograft test was carried out to observe tumorigenesis of the cell lines. In addition, two-dimensional electrophoresis (2-DE) and mass spectrometry were utilized to identify differentially expressed proteins between in Eahy926 cells and in A549 cells.</p> <p>Results</p> <p>The doubling time of EAhy926 cell and A549 cell proliferation was 25.32 h and 27.29 h, respectively (P > 0.1). Comparing the phase distribution of cell cycle of EAhy926 cells with that of A549 cells, the percentage of cells in G0/G1 phase, in S phase and in G2/M phase was (63.7% ± 2.65%) VS (60.0% ± 3.17%), (15.4% ± 1.52%) VS (13.8% ± 1.32%), and (20.9% ± 3.40%) VS (26.3% ± 3.17%), respectively (P > 0.05). For the ability of cell adhesion of EAhy926 cells and A549 cells, the value of OD in Eahy926 cells was significantly higher than that in A549 cells (0.3236 ± 0.0514 VS 0.2434 ± 0.0390, P < 0.004). We also found that the migration ability of Eahy926 cells was stronger than that of A549 cells (28.00 ± 2.65 VS 18.00 ± 1.00, P < 0.01), and that the invasion ability of Eahy926 cells was significantly weak than that of A549 cells (15.33 ± 0.58 VS 26.67 ± 2.52, P < 0.01). In the xenograft tumor model, expansive masses of classic tumor were found in the A549 cells group, while subcutaneous inflammatory focuses were found in the EAhy926 cells group. Besides, twenty-eight proteins were identified differentially expressed between in EAhy926 cells and in A549 cells by proteomics technologies.</p> <p>Conclusion</p> <p>As for the biological behaviors, the ability of cell proliferation in Eahy926 cells was similar to that in A549 cells, but the ability in adhesion and migration of Eahy926 cells was higher. In addition, Eahy926 cells had weaker ability in invasion and could not form tumor mass. Furthermore, there were many differently expressed proteins between hybrid cell line Eahy926 cells and A549 cells, which might partly account for some of the differences between their biological behaviors at the molecular level. These results may help to understand the processes of tumor angiogenesis, invasion and metastasis, and to search for screening method for more targets for tumor therapy in future.</p
RRx-001, an epigenetic-based radio- and chemosensitizer, has vascular normalizing effects on SCCVII and U87 tumors
BACKGROUND: The tumor-specific microregional effects of the anticancer agent RRx-001, a novel epigenetic-based radio/chemosensitizer with nitrogen oxide-donating properties in phase II clinical trials, were investigated with whole tissue section quantitative immunohistological staining in mouse SCCVII and human U87 tumors. RESULTS: SCCVII tumors exhibited regions of intermittent perfusion exemplified by co-localization of vessels with the hypoxia marker pimonidazole commonly occurring throughout the tissue. A moderate increase in perfusion (21 to 28 %) was observed after a bolus dose of the perivascular stain DiOC(7)(3), however, with the absence of an increase in tissue oxygenation. U87 tumors showed an absence of blood flow over large areas of treated tumors after dosing with RRx-001. However, these areas did not become necrotic and returned to near normal levels after 12 h. No significant change in tumor hypoxia was seen at 90 min or 12 h. For both tumor types, RRx-001 treatment resulted in the loss of perfusion in the large regions of the tumor; however, at the 12-h time point, both tumor types showed an increase in vessel perfusion but no significant decrease in hypoxia. CONCLUSIONS: These data suggest a redistribution of blood flow within the tumor for both tumor types akin to vascular normalization. Differences between the tumors were related to tumor architecture and distribution of alpha-smooth muscle actin (α-SMA). RRx-001 shows promise for short-term blood flow redistribution in tumors with a pericyte- and α-SMA-rich vasculature. Expression of α-SMA in tumor vasculature could therefore be useful for predicting tumor response to RRx-001
Systematic analysis of human microRNA divergence based on evolutionary emergence
AbstractMicroRNAs (miRNAs) play important roles in post-transcriptional gene expression control. To gain new insight into human miRNAs, we performed comprehensive sequence-based homology search for known human miRNAs to study the evolutionary distribution of human miRNAs. Furthermore, we carried out a series of studies to compare various features for different lineage-specific human miRNAs. Our results showed that major expansions of human miRNA genes coincide with the advent of vertebrates, mammals and primates. Further system-level analysis revealed significant differences in human miRNAs that arose from different evolutionary time points for a number of characteristics, implicating genetic and functional diversification for different human miRNAs during evolution. Our finds provide more useful knowledge for further exploring origins and evolution of human miRNA genes
Robust isothermal electric switching of interface magnetization: A route to voltage-controlled spintronics
Roughness-insensitive and electrically controllable magnetization at the
(0001) surface of antiferromagnetic chromia is observed using magnetometry and
spin-resolved photoemission measurements and explained by the interplay of
surface termination and magnetic ordering. Further, this surface in placed in
proximity with a ferromagnetic Co/Pd multilayer film. Exchange coupling across
the interface between chromia and Co/Pd induces an electrically controllable
exchange bias in the Co/Pd film, which enables a reversible isothermal (at room
temperature) shift of the global magnetic hysteresis loop of the Co/Pd film
along the magnetic field axis between negative and positive values. These
results reveal the potential of magnetoelectric chromia for spintronic
applications requiring non-volatile electric control of magnetization.Comment: Single PDF file: 27 pages, 6 figures; version of 12/30/09; submitted
to Nature Material
A review and a statistical analysis of porosity in metals additively manufactured by laser powder bed fusion
Additive manufacturing (AM), or 3D printing, is an emerging technology that âaddsâ materials up and constructs products through a layer-by-layer procedure. Laser powder bed fusion (LPBF) is a powder-bed-based AM technology that can fabricate a large variety of metallic materials with excellent quality and accuracy. However, various defects such as porosity, cracks, and incursions can be generated during the printing process. As the most universal and a near-inevitable defect, porosity plays a substantial role in determining the mechanical performance of as-printed products. This work presents a comprehensive review of literatures that focused on the porosity in LPBF printed metals. The formation mechanisms, evaluation methods, effects on mechanical performance with corresponding models, and controlling methods of porosity have been illustrated and discussed in-depth. Achievements in four representative metals, namely Tiâ6Alâ4V, 316L, Inconel 718, and AlSi10Mg, have been critically reviewed with a statistical analysis on the correlation between porosity fraction and tensile properties. Ductility has been determined as the most sensitive property to porosity among several key tensile properties. This review also provides potential directions and opportunities to address the current porosity-related challenges
Photosensitive drugs: a review on their photoprotection by liposomes and cyclodextrins.
Nowadays, an exciting challenge in the drug chemistry and technology research is represented by the development of methods aimed to protect molecular integrity and therapeutic activity of drugs from effects of light. The photostability characterization is ruled by ICH (The International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use), which releases details throughout basic protocols of stability tests to be performed on new medicinal products for human use. The definition of suitable photoprotective systems is fundamental for pharmaceutical manufacturing and for human healthy as well, since light exposure may affect either drugs or drug formulations giving rise even to allergenic or mutagenic by-products. Here, we summarize and discuss the recent studies on the formulation of photosensitive drugs into supramolecular systems, capable of entrapping the molecules in a hollow of their structure by weak noncovalent interactions and protecting them from light. The best known supramolecular matrices belong to the 'auto-assembled' structures, of which liposomes are the most representative, and the 'host-guest' systems, of which cyclodextrins represent the most common 'host' counterpart. A relevant number of papers concerning the use of both liposomes and cyclodextrins as photoprotection systems for drugs has been published over the last 20âyears, demonstrating that this topic captures interest in an increasing number of researchers
Exercise in obese pregnant women: The role of social factors, lifestyle and pregnancy symptoms
Background Physical activity may reduce the risk of adverse maternal outcomes, yet there are very few studies that have examined the correlates of exercise amongst obese women during pregnancy. We examined which relevant sociodemographic, obstetric, and health behaviour variables and pregnancy symptoms were associated with exercise in a small sample of obese pregnant women. Methods This was a secondary analysis using data from an exercise intervention for the prevention of gestational diabetes in obese pregnant women. Using the Pregnancy Physical Activity Questionnaire (PPAQ), 50 obese pregnant women were classified as "Exercisers" if they achieved â„900 kcal/wk of exercise and "Non-Exercisers" if they did not meet this criterion. Analyses examined which relevant variables were associated with exercise status at 12, 20, 28 and 36 weeks gestation. Results Obese pregnant women with a history of miscarriage; who had children living at home; who had a lower pre-pregnancy weight; reported no nausea and vomiting; and who had no lower back pain, were those women who were most likely to have exercised in early pregnancy. Exercise in late pregnancy was most common among tertiary educated women. Conclusions Offering greater support to women from disadvantaged backgrounds and closely monitoring women who report persistent nausea and vomiting or lower back pain in early pregnancy may be important. The findings may be particularly useful for other interventions aimed at reducing or controlling weight gain in obese pregnant women
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