40 research outputs found

    Cohomologies of modified λ\lambda-differential Lie triple systems and applications

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    In this paper, we introduce the concept and representation of modified λ\lambda-differential Lie triple systems. Next, we define the cohomology of modified λ\lambda-differential Lie triple systems with coefficients in a suitable representation. As applications of the proposed cohomology theory, we study 1-parameter formal deformations and abelian extensions of modified λ\lambda-differential Lie triple systems

    CONTROL OF STICKY CONTAMINANTS WITH CATIONIC TALC IN DEINKED PULP

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    In this study a cationic talc was applied to deinked pulp for control of sticky contaminants. Effects of the cationic talc on stickies and dissolved and colloid substances were investigated and compared with those of a conventional talc. Characteristics of wet-end chemistry were examined for the pulp with addition of both kinds of talc samples. Furthermore, influences on paper properties were also compared. The results showed that the addition of cationic talc can effectively decrease the content of stickies and DCS, while reducing the cationic demand of the pulp, and the turbidity of the filtrate. Deposition of stickies can be reduced by about 63% with the addition of 2.0% cationic talc into the pulp, and the DCS was reduced from 1989 mg/L to 1927 mg/L. Addition of cationic talc significantly increased the ash content of the paper, but it negatively influenced the paper strength properties

    Effect of cervical suspensory traction in the treatment of severe cervical kyphotic deformity

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    ObjectiveThis study aimed to investigate a new noninvasive traction method on the treatment of severe cervical kyphotic deformity.MethodsThe clinical data of patients with severe cervical kyphosis (Cobb > 40°) treated in Peking University Third Hospital from March 2004 to March 2020 were retrospectively summarized. 46 cases were enrolled, comprising 27 males and 19 females. Fifteen patients underwent skull traction, and 31 patients underwent suspensory traction. Among them, seven used combined traction after one week of suspensory traction. Bedside lateral radiographs were taken every two or three days during traction. The cervical kyphosis angle was measured on lateral radiographs in and extended position at each point in time. The correction rate and evaluated Japanese Orthopedic Association (JOA) scoring for the function of the spinal cord were also measured. The data before and after the operation were compared with paired sample t-test or Wilcoxon signed-rank test.ResultsNo neurological deterioration occurred during the skull traction and the cervical suspensory traction. There were 12 patients with normal neurological function, and the JOA score of the other 34 patients improved from 11.5 ± 2.8 to 15.4 ± 1.8 at the end of follow up (P < 0.05). The average kyphotic Cobb angle was 66.1° ± 25.2, 28.7° ± 20.1 and 17.4° ± 25.7 pre-traction, pre-operative, and at the final follow-up, respectively (P < 0.05). The average correction rate of skull traction and suspensory traction was 34.2% and 60.6% respectively. Among these, the correction rate of patients with simple suspensory traction was 69.3%. For patients with a correction rate of less than 40% by suspensory traction, combined traction was continued, and the correction rates after suspensory traction and combined traction were 30.7% and 67.1% respectively.ConclusionsPre-correction by cervical suspensory traction can achieve good results for severe cervical kyphotic deformity, with no wound and an easy process. Combined traction is effective for supplemental traction after suspensory traction

    Synthesis and Biological Activities of a 3′-Azido Analogue of Doxorubicin Against Drug-Resistant Cancer Cells

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    Doxorubicin (DOX), an anthracycline antibiotic, is one of the most active anticancer chemotherapeutic agents. The clinical use of DOX, however, is limited by the dose-dependant P-glycoprotein (P-gp)-mediated resistance. Herein, a 3′-azido analogue of DOX (ADOX) was prepared from daunorubicin (DNR). ADOX exhibited potent antitumor activities in drug-sensitive (MCF-7 and K562) and drug-resistant cell lines (MCF-7/DNR, K562/DOX), respectively. The drug resistance index (DRI) values of ADOX were much lower than that of DOX. The cytotoxicity experiments of ADOX or DOX against K562/DOX, with or without P-gp inhibitor, indicated that ADOX circumvents resistance by abolishing the P-gp recognition. This conclusion was further supported by drug influx/efflux flow cytometry experiments, as well as by molecular docking of ADOX to P-gp. In vivo animal tests, ADOX exhibited higher activity and less toxicity than DOX. The current data warranted ADOX for additional pre-clinical evaluations for new drug development

    Effect of the MoSi

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    This present study investigated the MoSi2 coating and its effect on reliability of bipropellant rocket engine. This coating is developed to protect the chamber substrate material form oxidization under hightemperature oxidative circumstance as bipropellant engine works. The multilayer structure of the MoSi2 coating shows excellent high-temperature and thermal-cycle resistance. Its characteristic of self-healing leads to the good performance under the long-time steady working condition for rocket engines. A 25000-seconds firing test was conducted to testify the performance of MoSi2 coating under high temperature above 1400℃. In addition, the influence of coating surface morphology on liquid film cooling was fully discussed in experiment and simulation. High-speed microscopy camera was used to study the effects of Weber number on the spreading and lasting of cooling liquid-film. the simulative comparison was conducted by OpenFOAM to present different transfer-heat modes, when a droplet impinges on the high-temperature surface of MoSi2 coating. All results show that higher smoothness of the coating is suitable for liquid-film cooling, strengthening liquid film spread and heat transfer. Moreover, scanning electron microscope (SEM) was used to study the effect of Mo layer residue on the coating thermal-cycle profermance. The test results indicates that Mo layer residue significantly cause penetrating cracks of the coating and then weaken the self-healing of the coating at downstream of throat. Therefore, it is important to strictly control the thickness of Mo layer by means of matching Mo target in ion plating. Thus after properly prolonging the infiltration time, Mo layer can be silicified completely without residue

    Simulation Analysis of the Effect of Slit/Slot Pintle Geometry on Atomization of Bipropellant Engine

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    In order to optimize the slit/slot geometry design of a bipropellant pintle injector, the impinging spray development of a pintle injector was numerically investigated. The VOF (volume of fluid) and LES (large eddy simulation) methods were employed for an analysis to capture the gas–liquid interface by means of the AMR (adaptive mesh refinement) method. In those simulation cases, different flowrates, slot numbers, pintle diameters, slot thicknesses and slot shapes were compared for an analysis. In a comparison of visualization and quantification, a high flowrate and large pintle diameter were shown to be more positive features for improving the atomization quality and mixing effect. As for the slot parameters and shape, the spray development was mainly determined by the flow proportion between the slit jet and slot jet. The simulation results indicated that dominant slot jets cause a more dispersed spatial distribution, which is more conducive to the subsequent improvement of combustion efficiency in a limited space. However, an excessive increase in the number of slot jets can weaken the overall atomization quality and mixing effect, so it is suggested to ensure a balance for geometry design optimization
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