Spatial characteristics of nanosecond pulsed micro-discharges in atmospheric pressure He/H2O mixture by optical emission spectroscopy

Atmospheric pressure micro-discharges in helium gas with a mixture of 0.5%water vapor between two pin electrodes are generated with nanosecond overvoltage pulses.The temporal and spatial characteristics of the discharges are investigated by means of time-resolved imaging and optical emission spectroscopy with respect to the discharge morphology,gas temperature,electron density,and excited species.The evolution of micro-discharges is captured by intensified CCD camera and electrical properties.The gas temperature is diagnosed by a two-temperature fit to the ro-vibrational OH(A^(2)Σ^(+)–X^П(2),0–0)emission band and is found to remain low at 425 K during the discharge pulses.The profile of electron density performed by the Stark broadening of Ha 656.1-nm and He I 667.8-nm lines is uniform across the discharge gap at the initial of discharge and reaches as high as 10^(23)m^(-3).The excited species of He,OH,and H show different spatio-temporal behaviors from each other by the measurement of their emission intensities,which are discussed qualitatively in regard of their plasma kinetics.

A multi-scale framework for life reduction assessment of turbine blade caused by microstructural degradation

The prolonged thermal exposure with centrifugal load results in microstructural degradation,which ultimately leads to a reduction in the fatigue and creep resistance of the turbine blades.The present work proposes a multi-scale framework to estimate the life reduction of turbine blades,which combines a microstructural degradation model,a two-phase constitutive model,and a microstructure-dependent fatigue and creep life reduction model.The framework with multi-scale models is validated by a Single Crystal(SC)Ni-based superalloy at the microstructural length-scale and is then applied to calculate the microstructural degradation and the fatigue and creep life reduction of turbine blades under two specific service conditions.The simulation results and quantitative analysis show that the microstructural degradation and fatigue and creep life reduction of the turbine blade are heavily influenced by the variations in the proportion of the intermediate state,namely,the maximum rotor speed status,in the two specific service conditions.The intermediate state accelerates the microstructural degradation and leads to a reduction of the life,especially the effective fatigue life reserve due to the higher temperature and rotational speed than that of the 93%maximum rotor speed status marked as the reference state.The proposed multi-scale framework provides a capable approach to analyze the reduction of the fatigue and creep life for turbine blade induced by microstructural degradation,which can assist to determine a reasonable Time Between Overhaul(TBO)of the engine.

Identification and Functional Analysis of Serum Specific miRNAs in Recurrent Aphthous Stomatitis Patients with Excess-heat or Yin-deficiency

Background:The treatment of Traditional Chinese Medicine(TCM)in recurrent aphthous stomatitis(RAS)based on syndrome differentiation has won the international acceptance,but the molecular mechanism of excess-heat syndrome and yin-deficiency syndrome of RAS remains unclear.Objective:To clarify specific microRNAs(miRNAs)and their functions in RAS patients with excess-heat or yin-deficiency.Methods:Serum samples were collected from patients meeting the RAS diagnostic criteria of excess-heat or yin-deficiency syndrome and healthy individuals.Core miRNAs were then identified under miRNA microarray anal-yses.Target prediction and bioinformatic analyses were carried out and gene-pathway-networks were visualized to better understand the relationship between different genes and pathways.Results:(1)90 individuals meeting the inclusion criteria were collected in this study.Among them,9 miRNAs were screened out in excess-heat syndrome group(EH group),with 1 upregulated and 8 downregulated.And four miRNAs(hsa-miR-20b-5p,hsa-miR-122-5p,hsa-miR-483-5p and hsa-miR-3197)were validated by real-time PCR method.14 miRNAs were screened out in yin-deficiency syndrome group(YD group)(7 upregulated and 7 downregulated).And hsa-miR-17-5p,hsa-miR-106-5p and hsa-miR-20b-5p were validated.(2)A total of 4,776 target genes were identified in EH group which enriched in GO categories including nervous system development and calcium ion binding and pathway such as PI3K-Akt signaling pathway and Calcium signaling pathway.10,172 target genes were identified in YD group which enriched GO categories included protein binding and positive regulation of transcription from RNA polymerase II promoter and pathway included MAPK signaling pathway and Ras signaling pathway.Conclusion:Hsa-miR-20b-5p in patients with RAS could act as the novel target for the classification of the syndrome.It is upregulated in RAS patients with excess-heat syndrome while downregulated in patients with yin-deficiency syndrome.The PI3K-Akt and MAPK signaling pathways and their related target genes may provide new insights into the molecular mechanisms of RAS with excess-heat syndrome or yin-deficiency syndrome,respectively.

An energy-based low-cycle fatigue life evaluation method considering anisotropy of single crystal superalloys

The crystal orientation significantly affects the low-cycle fatigue (LCF) propertiesof single crystal (SC) superalloys. However, the orientation-dependent LCF life model withprecise mechanisms and strong applicability is still lacking. This investigation aims at establishing an energy-based LCF life evaluation method that could consider the orientation effect. First,the influencing factors of anisotropy were identified through the literature review. Secondly, themultiaxial formula of the Ramberg-Osgood (ReO) equation was established to describe theanisotropic cyclic deformation characteristics. Furthermore, the strain energy density of SC superalloys was determined based on this equation, and the effective strain energy density wasintroduced to account for the effect of orientation. Finally, the energy-based method was validated by its application to several SC superalloys. Results showed that the crystallographicorientation with a lower Young’s modulus usually exhibits better LCF resistance. This phenomenon could be attributed to the different values of strain energy density dissipated in one cycle.The multiaxial ReO relationship could capture the anisotropic cyclic deformation response ofDD6. Compared with the classical methods, the energy-based model is favored by its precisemechanism and strong applicability. And it also exhibited better prediction accuracy. Most datapoints of different crystallographic orientations lay within the
3 error band.

Jieduquyuziyin Prescription Suppresses the Inflammatory Activity of Macrophages via NOTCH1/NF-κB Pathway

Background:Jieduquyuziyin prescription(JP)is a traditional Chinese medicine(TCM)formula,which has been applied to the treatment of systemic lupus erythematosus(SLE)for decades,and its efficacy and safety have been confirmed in clinical practice.However,little is known about its molecular mechanism.Objective:To explore the effects of JP on macrophages’inflammatory activity and NOTCH1/NF-κB pathway.Methods:The JP-treated serum was prepared to determine its optimal concentration.Given the fact that active components in rats’serum might affect the results,control serum without JP components was prepared simul-taneously.Lipopolysaccharide(LPS)was used to activate RAW264.7,and the cells were interfered with DAPT(NOTCH1 blocker),control serum,and JP-treated serum,respectively.After the above intervention,the expres-sion of NOTCH1 and RBPJ,the nuclear translocation of NF-κB,and the extracellular release of IL6,TNF𝛼,and NO,was evaluated by real-time reverse transcription-polymerase chain reaction(RT-PCR),western blotting(WB),enzyme-linked immunosorbent assay(ELISA),and Griess method.Results:Both DAPT and JP-treated serum could significantly suppress the expression of NOTCH1 and RBPJ induced by LPS,as well as the nuclear translocation of NF-κB,leading to the decreased release of IL6,TNF𝛼,and NO,while control serum had little effect on macrophage activity and NOTCH1/NF-κB pathway.Conclusion:These results demonstrated the effects of JP on macrophage activation and pro-inflammatory response and suggested that the molecular mechanism of JP might attribute to the inhibition of the NOTCH1/NF-κB path-way.Besides,previous studies suggested that paeoniflorin and ferulic acid are two major effective components in JP.In subsequent experiments,we would further explore the effects of these two components on MRL/lpr mice and macrophage activity.

Ethyl Acetate Fraction in Hedyotis Diffusa Willd Inhibits T Cell Proliferation to Improve the Pathogenesis of Systemic Lupus Erythematosus

Background:Abnormal proliferation of T cells plays an essential role in the pathogenesis of Systemic lupus erythematosus(SLE).The pharmaceutical effect of Hedyotis Diffusa Willd(HDW)on SLE has been investigated previously.Nevertheless,the biomedical mechanism is still left unclear.Objective:This study has been arranged to evaluate the therapeutic effect of the ethyl acetate fraction of HDW(EAHDW)on lupus mice and explore the potential therapeutic mechanism.Methods:EAHDW was prepared with 80%ethanol reflex extraction followed by successive extraction,and ana-lyzed with HPLC and UPLC-Q/TOP-MS.The potential targets and STAT3 affinity regulators were predicted with network pharmacology.The pharmaceutic effect of EAHDW was studied with MRL/lpr mice.Cytokines and au-toantibodies were quantified with ELISA assays.The pathological damage of glomerulus and STAT3 expression in the kidney was detected with histochemical and immunohistochemical techniques.The cell cycle properties in cell proliferation were identified with the flow cytometry.The western blot and dual-Luciferase reporter assay were applied to evaluate translational and transcriptional activity of STAT3,respectively.Results:In this study,the extraction ratio of EAHDW was 2.7±1%,in which 19 ingredients were identified.Network pharmacological analysis showed that the target genes of EAHDW were highly focused on influencing the abnormal T cell proliferation in SLE.EAHDW showed the beneficial effects on pathological changes and STAT3 expression in the glomerulus of lupus mice,and the levels of cytokines and autoantibodies in serum.In cytological study,EAHDW treatment attenuated the transcription and phosphorylation of STAT3,which inhibited T cell proliferation by prolonged S-phase of the cell cycle.A total of 5 compounds in EAHDW exhibited high docking affinity to the DNA-binding site of STAT3.Conclusion:EAHDW could reduce the inflammatory response and inhibit the proliferation of T cells by interfering with the STAT3 signaling pathway,thereby playing a therapeutic effect on SLE.