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  • Royal Society  (24)
  • American Association for the Advancement of Science (AAAS)  (18)
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Years
  • 1
    Publication Date: 2018-08-23
    Description: In experimental investigations on axial symmetry, over-ventilated CH 4 /air diffusion combustion in a packed bed is executed to study the height, shape and stability of the flame. The combustor is a quartz tube packed with alumina pellets in which a cylindrical fuel stream is surrounded by a coflow air nozzle. The results show that the bed length and pellet diameter have a significant influence on the flame properties. In general, the flame above the pellet surface has axial symmetry, and its shape and colour are similar to those of a conventional diffusion flame when the bed length is smaller. The colour of the flame front varies with the bed length. The changed colour indicates an increased flame front temperature and that the combustion regime above the bed surface may change from non-premixed combustion to partially premixed combustion or even premixed combustion owing to the mix and dispersion effect in the packed bed. In addition, multiple flame behaviours, such as an inclined flame front, isolated reaction zone and oscillatory motion followed by a pulsating sound with a few hertz in a packed bed, are observed experimentally. The possible reasons for these phenomena are discussed.
    Keywords: energy
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 2
    Publication Date: 2018-09-20
    Description: Supramolecular nanoassemblies that respond to multiple stimuli exhibit high therapeutic efficacy against malignant tumors. We report a new type of supramolecular nanofiber that integrates targeting peptide–coated magnetic nanoparticles with β-cyclodextrin–bearing polysaccharides in a complex held together by multivalent interactions. The nanofibers not only exhibited reversible photo-triggered association and disassociation depending on irradiation wavelength but also underwent magnetic field–controlled directional aggregation, even in the rather weak geomagnetic field. The nanofibers markedly suppressed invasion by and metastasis of cancer cells both in vitro and in vivo. Furthermore, compared with control mice, tumor-burdened mice treated with the nanofibers showed a lower rate of mortality from the metastatic spread of tumor cells. Our results suggest that these geomagnetism- and photo-controlled nanofibers may facilitate the rapid development of efficacious anticancer therapies.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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  • 3
    Publication Date: 2018-09-13
    Description: The present study introduces thermogravimetry with gas chromatography–mass spectrometry (TG-GC-MS) at four different heating rates to investigate the activation energy and thermal degradation behaviour of walnut shell pyrolysis. The distributed activation energy model (DAEM) was applied to investigate the activation energy. According to values of the activation energy and the correlation coefficient by the DAEM, the activation energy (98.69–267.75 kJ mol –1 ) and correlation coefficient (0.914–0.999) were determined for pyrolysis of walnut shells. GC-MS was performed to investigate the pyrolysis products from walnut shells at different critical temperature points. More than 20 different substances were identified at different temperatures from GC-MS results. With the increasing pyrolysis temperature, furan, furfural, benzene and long chain alkanes were successively identified in different GC-MS experimental results.
    Keywords: energy
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 4
    Publication Date: 2018-09-13
    Description: Targeting fibroblast-like synoviocyte (FLS) migration and invasion-mediated bone erosion is a promising clinical strategy for the treatment of rheumatoid arthritis (RA). Drug sensitivity testing is fundamental to this scheme. We designed a microfluidic chip-based, cell co-cultured platform to mimic RA FLS-mediated bone erosion and perform drug-sensitive assay. Human synovium SW982 cells were cultured in the central channel and migrated to flow through matrigel-coated side channels towards cell culture chamber where RANKL-stimulated osteoclastic RAW264.7 and osteogenic medium (OS)-stimulated bone marrow mesenchymal stem cells (BMSC) were cultured in the microfluidic chip device, mimicking FLS migration and invasion-mediated bone erosion in RA. These SW982 cells showed different migration potentials to osteoclasts and BMSC. The migration of SW982 cells with high expression of cadherin-11 was more potent when SW982 cells were connected with the co-culture of RAW264.7 and BMSC. Simultaneously, in the co-cultured chamber, tartrate-resistant acid phosphatase (TRAP) activity of RANKL-stimulated RAW264.7 cells was enhanced, but alkaline phosphatase (ALP) activity was decreased in comparison with mono-cultured chamber. Furthermore, it was confirmed that celastrol, a positive drug for the treatment of RA, inhibited SW982 cell migration as well as TRAP activity in the cell-cultured microfluidic chips. Thus, the migration and invasion to bone-related cells was reconstituted on the microfluidic model. It may provide an effective anti-RA drug screen model for targeting FLS migration-mediated bone erosion.
    Keywords: biochemistry, health and disease and epidemiology
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 5
    Publication Date: 2018-10-11
    Description: Broken gangue consists of different particles, and it has more complicated seepage characteristics than intact rock sample. Using the self-designed instrument, the permeability, mass loss and pore pressure of crushed gangue during the seepage are tested. The result shows that permeability parameter k of crushed rock has a polynomial relationship with effective stress ' in inverse proportion, and permeability parameter β of crushed gangue has power exponent relationship with effective stress ' increasing in direct proportion. The particle size of 8.0–10.0 mm has a good support effect. The inner pressure of crushed rock is mostly linear distribution along the tube wall. After the seepage, mass loss of broken gangue mainly increases with large particle size out of proportion.
    Keywords: hydrology, civil engineering, engineering geology
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 6
    Publication Date: 2018-11-03
    Description: Quantum oscillations are usually the manifestation of the underlying physical nature in condensed matter systems. Here, we report a new type of log-periodic quantum oscillations in ultraquantum three-dimensional topological materials. Beyond the quantum limit (QL), we observe the log-periodic oscillations involving up to five oscillating cycles (five peaks and five dips) on the magnetoresistance of high-quality single-crystal ZrTe 5 , virtually showing the clearest feature of discrete scale invariance (DSI). Further, theoretical analyses show that the two-body quasi-bound states can be responsible for the DSI feature. Our work provides a new perspective on the ground state of topological materials beyond the QL.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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  • 7
    Publication Date: 2018-11-23
    Description: Alloy design based on single–principal-element systems has approached its limit for performance enhancements. A substantial increase in strength up to gigapascal levels typically causes the premature failure of materials with reduced ductility. Here, we report a strategy to break this trade-off by controllably introducing high-density ductile multicomponent intermetallic nanoparticles (MCINPs) in complex alloy systems. Distinct from the intermetallic-induced embrittlement under conventional wisdom, such MCINP-strengthened alloys exhibit superior strengths of 1.5 gigapascals and ductility as high as 50% in tension at ambient temperature. The plastic instability, a major concern for high-strength materials, can be completely eliminated by generating a distinctive multistage work-hardening behavior, resulting from pronounced dislocation activities and deformation-induced microbands. This MCINP strategy offers a paradigm to develop next-generation materials for structural applications.
    Keywords: Materials Science
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
    Publication Date: 2018-07-19
    Description: Layer-by-layer (LbL) self-assembly is the technology used in intermolecular static electricity, hydrogen bonds, covalent bonds and other polymer interactions during film assembling. This technology has been widely studied in the drug carrier field. Given their use in drug delivery systems, the biocompatibility of these potential compounds should be addressed. In this work, the primary biocompatibility of poly(lactide-co-glycolide)-(poly-L-orithine/fucoidan) [PLGA-(PLO/fucoidan)] core–shell nanoparticles (NPs) was investigated. Atomic force microscopy revealed the PLGA-(PLO/Fucoidan) 4 NPs to be spherical, with a uniform size distribution and a smooth surface, and the NPs were stable in physiological saline. The residual amount of methylene chloride was further determined by headspace gas chromatography, in which the organic solvent can be volatilized during preparation. Furthermore, cell viability, acridine orange/ethidium bromide staining, haemolysis and mouse systemic toxicity were all assessed to show that PLGA-(PLO/fucoidan) 4 NPs were biocompatible with cells and mice. Therefore, these NPs are expected to have potential applications in future drug delivery systems.
    Keywords: biomaterials
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 9
    Publication Date: 2018-08-16
    Description: Seven new cucurbitane glucosides, hemslepensides J-P ( 1 – 7 ), and two known compounds, 16,25- O -diacetyl-cucurbitane F ( 8 ) and 25- O -acetyl-23,24-dihydrocucurbitacin F ( 9 ), were isolated from the tubers of Hemsleya pengxianensis var. jinfushanensis . The structures of 1 – 7 were elucidated using infrared absorption spectroscopy, nuclear magnetic resonance spectroscopy and high-resolution electrospray ionization mass spectrometry. The treatment of HT29 cells, human colon cancer cells, with compounds 8 and 9 inhibited cell proliferation. Further study demonstrated that compounds 8 and 9 induced F-actin aggregation, G 2 /M phase cell cycle arrest and cell apoptosis in HT29 cells. In summary, the present study enriched the chemical composition research of H. pengxianensis , and suggested that the compounds 8 / 9 treatment may be a potentially useful therapeutic option for colon cancer.
    Keywords: medicinal chemistry, plant science
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 10
    Publication Date: 2018-08-16
    Description: Types of resins anchored on citric acid were synthesized and identified. The citric acid-modified resins PS-CA, PS-O-CA and PS-N-CA were synthesized by anchoring citric acid on PS-Cl, PS-OH and PS-NH 2 , respectively. The PS-CA, PS-O-CA and PS-N-CA were used to adsorb Fe 3+ , Al 3+ , Cu 2+ , Pb 2+ , Cd 2+ and Hg 2+ . The influences of pH, adsorption time and metal ion concentration on the adsorption capacities of the resins were investigated. After optimization, PS-CA was a good adsorbent to Fe 3+ , Cu 2+ , Pb 2+ and Cd 2+ with q m values of 143.9 mg g –1 , 77.4 mg g –1 , 18.9 mg g –1 and 119.9 mg g –1 , respectively. PS-N-CA was a good adsorbent to Al 3+ and Hg 2+ with q m values of 176.6 mg g –1 and 114.9 mg g –1 , respectively. The adsorption kinetics and adsorption isotherm experiments indicated that the pseudo-first-order rate equation was more appropriate for characterizing the kinetic data and the Langmuir model was more suitable for fitting the equilibrium data. The reusability of the citric acid-modified resins was also evaluated and these resins exhibited considerable reusability.
    Keywords: chemical engineering
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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