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Now showing items 65 - 80 of 1499

  • Size-dependent thermal decomposition and kinetics of ultrafine alkali metal styphnates

    Liu, Rui   Zhao, Wenyuan   Zhang, Tonglai   Yang, Li   Zhou, Zunning   Qi, Shuyuan  

    Three alkali metal styphnates, K2TNR, Rb2TNR and Cs2TNR, were fabricated into different particle sizes by the crystal-morphology-control microemulsion synthesis. The thermal decomposition and kinetics were studied by DSC and DPTA techniques. As the particle size decreases, the thermodynamic and kinetic parameters decrease while the decomposition gas amounts and reaction rate constants increase. The reduction in particle size leads to an increase in reactivity and a decrease in thermal stability. The thermal sensitivity, determined by 5 s explosion temperature and flame sensitivity, grows with decreasing particle size. The ultrafine materials have small particle size and large specific surface area, and therefore possess strong surface bonding energy, low activation energy barrier and high reactivity. In the case of the same size, the order of thermal stability is Cs2TNR < Rb2TNR < K2TNR. The central metal of small atomic radius has strong coordination bonding energy and therefore determines the high stability.
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  • Analysis, simulation and fabrication of MEMS springs for a micro-tensile system

    Liu, Rui   Wang, Hong   Li, Xueping   Tang, Jun   Mao, Shengping   Ding, Guifu  

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  • Evaluation of Radiation Effects in RRAM based Neuromorphic Computing System for Inference

    Ye, Zhilu   Liu, Rui   Taggart, Jennifer   Barnaby, Hugh   Yu, Shimeng  

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  • A micro-tensile method for measuring mechanical properties of MEMS materials

    Liu, Rui   Wang, Hong   Li, Xueping   Ding, Guifu   Yang, Chunsheng  

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  • A SEALED FUEL CELL UNIT WITH A PROTON-EXCHANGE MEMBRANE

    A sealed proton-exchange membrane fuel cell unit of this invention comprises an MEA component, a sealing unit, and current collectors for the positive and negative electrodes. The current collectors press the MEA components from each side. The MEA components comprise a proton-exchange membrane, and the positive and negative electrodes attached to each side of the membrane. The sealing unit covers the edges of the proton-exchange membrane, and comprises a first positioning unit and a second positioning unit. The first positioning unit is located on each side of said sealing unit facing the respective current collectors for the negative and positive electrodes. At the corresponding locations on the current collectors for the negative and positive electrodes there are second positioning unit. The first and second positioning units match each other. By matching the locations of the first and second positioning units, the negative and positive current collectors are not likely to slide against each other. Thus the cell is more tightly sealed to achieve better air-tightness.
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  • AN UNORTHODOX X-CLASS LONG-DURATION CONFINED FLARE

    Liu, Rui   Titov, Viacheslav S.   Gou, Tingyu   Wang, Yuming   Liu, Kai   Wang, Haimin  

    We report the observation of an X-class long-duration flare which is clearly confined. It appears as a compact-loop flare in the traditional EUV passbands (171 and 195 angstrom), but in the passbands sensitive to flare plasmas (94 and 131 angstrom), it exhibits a cusp-shaped structure above an arcade of loops like other long-duration events. Inspecting images in a running difference approach, we find that the seemingly diffuse, quasi-static cusp-shaped structure consists of multiple nested loops that repeatedly rise upward and disappear approaching the cusp edge. Over the gradual phase, we detect numerous episodes of loop rising, each lasting minutes. A differential emission measure analysis reveals that the temperature is highest at the top of the arcade and becomes cooler at higher altitudes within the cusp-shaped structure, contrary to typical long-duration flares. With a nonlinear force-free model, our analysis shows that the event mainly involves two adjacent sheared arcades separated by a T-type hyperbolic flux tube (HFT). One of the arcades harbors a magnetic flux rope, which is identified with a filament that survives the flare owing to the strong confining field. We conclude that a new emergence of magnetic flux in the other arcade triggers the flare, while the preexisting HFT and flux rope dictate the structure and dynamics of the flare loops and ribbons during the long-lasting decay phase, and that a quasi-separatrix layer high above the HFT could account for the cusp-shaped structure.
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  • atoms and Br?nsted acidity in ZSM-23 zeolite

    Liu, Rui   Zhang, Jie   Sun, Xiuliang   Huang, Chongpin   Chen, Biaohua  

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  • Using soy protein SiOx nanocomposite film coating to extend the shelf life of apple fruit

    Liu, Rui   Liu, Dingyu   Liu, Yan   Song, Yingshi   Wu, Tao   Zhang, Min  

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  • Stroke risk in treatment of type 2 diabetes in China: a 7 year retrospective cohort study

    Liu, Rui   Wang, Qing   Szeto, Vivian   Barszczyk, Andrew   Jin, Tianru   Mannucci, Edoardo   Sun, Hong-Shuo   Feng, Zhong-Ping  

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  • Reducing TDP-43 aggregation does not prevent its cytotoxicity

    Liu, Rui   Yang, Guang   Nonaka, Takashi   Arai, Tetsuaki   Jia, William   Cynader, Max S  

    Background TAR DNA-binding protein 43 (TDP-43) is a protein that is involved in the pathology of Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD). In patients with these neurodegenerative diseases, TDP-43 does not remain in its normal nuclear location, but instead forms insoluble aggregates in both the nucleus and cytoplasm of affected neurons. Results We used high density peptide array analysis to identify regions in TDP-43 that are bound by TDP-43 itself and designed candidate peptides that might be able to reduce TDP-43 aggregation. We found that two of the synthetic peptides identified with this approach could effectively inhibit the formation of TDP-43 protein aggregates in a concentration-dependent manner in HeLa cells in which a mutated human TDP-43 gene was overexpressed. However, despite reducing aggregation, these peptides did not reduce or prevent cell death. Similar results were observed in HeLa cells treated with arsenite. Again we found reduced aggregation, in this case of wild type TDP-43, but no difference in cell death. Conclusions Our results suggest that TDP-43 aggregation is associated with the cell death process rather than being a direct cause.
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  • The Effect of Magnetic Reconnection and Writhing in a Partial Filament Eruption

    Liu, Rui   Gilbert, Holly R.   Alexander, David   Su, Yingna  

    We present observations from 2007 March 2 of a partial filament eruption characterized by two distinct phases of writhing motions: a quasi-static, slowly evolving phase followed by a rapid kinking phase showing a bifurcation of the filament. The quasi-static kinking motions are observed before there is any heating or flaring evident in EUV or soft X-ray (SXR) observations. As the writhe of the filament develops, a sigmoid becomes sharply defined in the SXR. Prior to eruption onset, the sigmoid in the EUV appears to be composed of two separate looplike structures, which are discontinuous at the projected location where the sigmoid crosses the filament. Coincident with the onset of the eruption and the production of a GOES class B2 flare, the original "two-loop'' EUV sigmoid is now observed as a single continuous structure lying above the filament, signifying the presence of magnetic reconnection and the associated dissipative heating of field lines above the filament. During the eruption, the escaping portion of the filament rotates quickly and erupts together with the expanding arched sigmoid. The portion of the filament that is left behind develops into an inverse S-shaped configuration. The separation of the filament, the EUV brightening at the separation location, and the surviving sigmoidal structure are all signatures of magnetic reconnection occurring within the body of the original filament. Other features of the same event reported by Sterling and coworkers, e. g., the flux cancellation at the polarity inversion line prior to the eruption and the SXR compact loop formed underneath the erupting sigmoid during the eruption, indicate that magnetic reconnection also occurred in the sheared core field beneath the filament. These results suggest that a combination of the kinking motions and internal tether-cutting are responsible for the initiation of the eruption.
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  • Transient electroluminescence spikes in small molecular organic light-emitting diodes

    Liu, Rui   Gan, Zhengqing   Shinar, Ruth   Shinar, Joseph  

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  • The Prognostic Role of a Gene Signature from Tumorigenic Breast-Cancer Cells

    Liu, Rui   Wang, Xinhao   Chen, Grace Y.   Dalerba, Piero   Gurney, Austin   Hoey, Timothy   Sherlock, Gavin   Lewicki, John   Shedden, Kerby   Clarke, Michael F.  

    BACKGROUND: Breast cancers contain a minority population of cancer cells characterized by CD44 expression but low or undetectable levels of CD24 (CD44+CD24-/low) that have higher tumorigenic capacity than other subtypes of cancer cells. METHODS: We compared the gene-expression profile of CD44+CD24-/low tumorigenic breast-cancer cells with that of normal breast epithelium. Differentially expressed genes were used to generate a 186-gene ``invasiveness'' gene signature (IGS), which was evaluated for its association with overall survival and metastasis-free survival in patients with breast cancer or other types of cancer. RESULTS: There was a significant association between the IGS and both overall and metastasis-free survival (P<0.001, for both) in patients with breast cancer, which was independent of established clinical and pathological variables. When combined with the prognostic criteria of the National Institutes of Health, the IGS was used to stratify patients with high-risk early breast cancer into prognostic categories (good or poor); among patients with a good prognosis, the 10-year rate of metastasis-free survival was 81%, and among those with a poor prognosis, it was 57%. The IGS was also associated with the prognosis in medulloblastoma (P=0.004), lung cancer (P=0.03), and prostate cancer (P=0.01). The prognostic power of the IGS was increased when combined with the wound-response (WR) signature. CONCLUSIONS: The IGS is strongly associated with metastasis-free survival and overall survival for four different types of tumors. This genetic signature of tumorigenic breast-cancer cells was even more strongly associated with clinical outcomes when combined with the WR signature in breast cancer.
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  • CONTRACTING AND ERUPTING COMPONENTS OF SIGMOIDAL ACTIVE REGIONS

    Liu, Rui   Liu, Chang   T?r?k, Tibor   Wang, Yuming   Wang, Haimin  

    It has recently been noted that solar eruptions can be associated with the contraction of coronal loops that are not involved in magnetic reconnection processes. In this paper, we investigate five coronal eruptions originating from four sigmoidal active regions, using high-cadence, high-resolution narrowband EUV images obtained by the Solar Dynamic Observatory (SDO). The magnitudes of the flares associated with the eruptions range from GOES class B to class X. Owing to the high-sensitivity and broad temperature coverage of the Atmospheric Imaging Assembly (AIA) on board SDO, we are able to identify both the contracting and erupting components of the eruptions: the former is observed in cold AIA channels as the contracting coronal loops overlying the elbows of the sigmoid, and the latter is preferentially observed in warm/hot AIA channels as an expanding bubble originating from the center of the sigmoid. The initiation of eruption always precedes the contraction, and in the energetically mild events (B- and C-flares), it also precedes the increase in GOES soft X-ray fluxes. In the more energetic events, the eruption is simultaneous with the impulsive phase of the nonthermal hard X-ray emission. These observations confirm that loop contraction is an integrated process in eruptions with partially opened arcades. The consequence of contraction is a new equilibrium with reduced magnetic energy, as the contracting loops never regain their original positions. The contracting process is a direct consequence of flare energy release, as evidenced by the strong correlation of the maximal contracting speed, and strong anti-correlation of the time delay of contraction relative to expansion, with the peak soft X-ray flux. This is also implied by the relationship between contraction and expansion, i.e., their timing and speed.
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  • In vitro activity of Lycium barbarum (Goji) against major human phase I metabolism enzymes

    Liu, Rui   Tam, Teresa W.   Mao, Jingqin   Salem, Ammar   Arnason, John T.   Krantis, Anthony   Foster, Brian C.  

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  • Enzyme Responses to Phytoremediation of PAH-Contaminated Soil UsingEchinacea purpurea(L.)

    Liu, Rui   Zhao, Lixing   Jin, Caixia   Xiao, Nan   Jadeja, R. N.   Sun, Ting  

    Pot-culture experiments were performed to study the relationship between enzyme activity and polycyclic aromatic hydrocarbon (PAH) degradation by sowing Echinacea purpurea (L.) in aged PAH-contaminated soils. E. purpurea (L.) was cultivated in PAH-contaminated soils for 60, 120, and 150 days. The data showed that the rate of removal of fluoranthene, pyrene, benzo(a) anthracene, chrysene, benzo (b) fluoranthene, benzo(k) fluoranthene, benz(a) pyrene, and dibenzo(a, h) anthracene was 92.92 % at 150 days. Furthermore, there was a better recovery of these eight PAHs from the PAH-contaminated soils in comparison with the unplanted soils at 120 days, and the recovery from the PAH-contaminated soils was higher than that from the control soils. Significant reductions were detected in the levels of these eight PAHs, corresponding to 96.21, 94.53, 97.35, 90.70, 99.64, 97.34, 86.67, and 89.90 %, respectively. The activities of dehydrogenase, polyphenol oxidase, and urease increased as a result of PAH treatment, and these effects were suppressed over time. The activities of peroxidase and alkaline phosphatase were reduced, which suggests that these enzymes are sensitive to PAHs. The data in this study revealed that enzyme activities were strongly correlated to the higher degradation performance of the E. purpurea (L.) plant on PAH-contaminated soil. More researches are required to elucidate the mechanisms underlying PAH detoxification and degradation in contaminated soil.
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