Accurate measurement of aerosol optical properties using the multilongitudinal mode high-spectral-resolution lidar with self-tuning Mach-Zehnder interferometer

The multilongitudinal mode[MLM]high-spectral-resolution lidar[HSRL]based on the Mach±Zehnder interferometer[MZI]is constructed in Xi’an for accurate measurements of aerosol optical properties.The critical requirement of the optimal match between the free spectral range of MZI and the longitudinal mode interval of the MLM laser is influenced by the laboratory temperature,pressure,and vibration.To realize the optimal separation of aerosol Mie scattering signals and molecular Rayleigh scattering signals excited by the MLM laser,a self-tuning technique to dynamically adjust the optical path difference[OPD]of the MZI is proposed,which utilizes the maximum ratio between the received power of the Mie channel and Rayleigh channel as the criterion of the OPD displacement.The preliminary experiments show the feasibility of the MLM-HSRL with self-tuning MZI and the stable performance in the separation of aerosol Mie scattering signals and molecular Rayleigh scattering signals.

Correlation between the lidar ratio and the Angstrom exponent of various aerosol types

Lidar ratios and AngstrOm exponents of continental,maritime,and desert aerosols were calculated to evaluate the effects of aerosol composition on these parameters.Their correlation was assessed using correlation analysis and curve fitting.The Pearson correlation coefficient between the lidar ratio and the AngstrOm exponent was larger than 0.95 in all cases.We verified the reliability of the Pearson correlation coefficient using the significance test.The relationship between the lidar ratio and the Angstrom expo- nent of continental aerosol can be described by a cubic polynomial model;thus,the function relation between the change in lidar ratios at different laser wavelengths depends on the fitting coefficients and the AngstrOm exponent.The relationship between the lidar ratio and the AngstrOm exponent of both maritime and desert aerosols can be described by a linear model.In these aerosols,the linear change in lidar ratios at different laser wavelengths remains unaffected by the AngstrOm exponent.The changes in the lidar ratio in maritime aerosol at 355nm and 532nm are -0.7times and -0.18times that at 1064nm, respectively.For desert aerosol,the changes in the lidar ratio at 355nm and 532nm are 0.37 times and 1.88times that at 1064nm,respectively.

Apoptotic extracellular vesicles restore homeostasis of the articular microenvironment for the treatment of rheumatoid arthritis

Rheumatoid arthritis(RA)is a severe autoimmune disease with symptoms including synovial inflammation,cartilage erosion,and bone loss in RA lesions,which eventually lead to joint deformity and function loss.Most current treatments fail to achieve satisfying therapeutic outcomes with some adverse effects.Extracellular vesicles derived from apoptotic cells(apoEVs)have emerged as important mediators in intercellular communication regulating diverse physiological and pathological processes.In this study,we investigated the therapeutic efficacy of macrophage-derived and osteoclast-derived apoEVs(Mφ-apoEVs and OC-apoEVs)on RA.The in vitro results showed that both Mφ-apoEVs and OC-apoEVs induced macrophage repolarization toward the anti-inflammatory M2 phenotype,promoted chondrocyte functions and chondrogenesis,and inhibited osteoclast formation and maturation.In addition,OC-apoEVs promoted osteogenic differentiation.The in vivo study on the CIA mouse model further demonstrated that apoEVs could couple various functions and exert synergistic effects on the joint with RA,as evidenced by the regression of synovial inflammation,the reversal of cartilage damage and bone erosion,and the preservation of joint structure.These findings demonstrated that Mφ-apoEVs and OC-apoEVs contributed to restoring the homeostasis of the overall microenvironment in the RA joint and highlighted their potential application as a promising alternative to treat RA.

金属氧化物半导体气敏材料抗湿性能提升策略

金属氧化物半导体气体传感器是目前研究和应用最为广泛的气体传感器之一,具有高灵敏、长寿命和低成本等优点。然而,金属氧化物半导体气敏材料在湿润环境中会与水蒸气发生相互作用,导致传感器的基线电阻发生漂移,气敏性能受到显著影响,成为传感器应用中面临的瓶颈问题。针对该问题,研究者们从抑制水的表面吸附、水与氧的竞争吸附及调控水与吸附氧的反应三个方面开发了一些金属氧化物半导体气敏材料的抗湿性能提升策略,从而提升金属氧化物半导体气敏材料的抗湿性。本文对水蒸气的影响机理进行了分析,对三类抗湿提升策略的未来发展提出展望,有望为金属氧化物半导体气敏材料抗湿性能的提升提供解决思路与方法指导。

Astragaloside Ⅳ suppresses post-ischemic natural killer cell infiltration and activation in the brain:involvement of histone deacetylase inhibition

Natural killer(NK)cells,a type of cytotoxic lymphocytes,can infiltrate into ischemic brain and exacerbate neuronal cell death.Astragaloside Ⅳ(ASIV)is the major bioactive ingredient of Astragalus membranaceus,a Chinese herbal medicine,and possesses potent immunomodulatory and neuroprotective properties.This study investigated the effects of ASIV on post-ischemic brain infiltration and activation of NK cells.ASIV reduced brain infarction and alleviated functional deficits in MCAO rats,and these beneficial effects persisted for at least 7 days.Abundant NK cells infiltrated into the ischemic hemisphere on day 1 after brain ischemia,and this infiltration was suppressed by ASIV.Strikingly,ASIV reversed NK cell deficiency in the spleen and blood after brain ischemia.ASIV inhibited astrocyte-derived CCL2 upregulation and reduced CCR2+NK cell levels in the ischemic brain.Meanwhile,ASIV attenuated NK cell activating receptor NKG2D levels and reduced interferon-γproduction.ASIV restored acetylation of histone H3 and the p65 subunit of nuclear factor-κB in the ischemic brain,suggesting inhibition of histone deacetylase(HDAC).Simultaneously,ASIV prevented p65 nuclear translocation.The effects of ASIV on reducing CCL2 production,restoring acetylated p65 levels and preventing p65 nuclear translocation were mimicked by valproate,an HDAC inhibitor,in astrocytes subjected to oxygen-glucose deprivation.Our findings suggest that ASIV inhibits post-ischemic NK cell brain infiltration and activation and reverses NK cell deficiency in the periphery,which together contribute to the beneficial effects of ASIV against brain ischemia.Furthermore,ASIV’s effects on suppressing NK cell brain infiltration and activation may involve HDAC inhibition.