Quantitative solution of size and dosage of capsules for self-healing of cracks in cementitious composites

Haifeng Yuan,Huisu Chen 사단법인 한국계산역학회 2013 Computers and Concrete, An International Journal Vol.11 No.3

Self-healing (SH) technology of cracking is becoming a promising solution to improve the durability of cement based composites. However, little formula are available in the literature on determining the size and dosage of the self-healing capsules. Supposed that SH capsules will be broken and activated when they met cracks, a theoretical solution is developed to calculate the appropriate length of SH capsules based on Buffon’s needle model. Afterwards, a method to calculate the dosage of capsules was proposed in terms of stereological theory. The reliability of the above mentioned theoretical methods was verified by computer simulation. An experiment of self-healing in mortar was performed as well, by which the theoretical models were verified.

Shakedown analysis of a wind turbine gear considering strain-hardening and the initial residual stress

Haifeng He,Hua iju Liu,Caichao Zhu,Longhua Yuan 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.11

Under some heavy-duty conditions, the shakedown state may occur on gears such as those used in a megawatt wind turbine gearbox. The plastic deformation and the residual stress formed within the shakedown process further influence the contact behavior and the service life of the gear. The initial residual stress caused by the heat treatment of the case-hardening gear, together with the strain-hardening constitutive behavior of the material, have a combined effect on the shakedown state. A two-dimensional elastic-plastic contact numerical model was developed for a case-hardened wind turbine gear to study effects of the initial residual stress and the strain-hardening properties. Plastic strain and residual stress are calculated at each loading cycle without the consideration of the tooth friction. The initial yield limit and the hardening modulus of the material were obtained through a tension test on a universal tensile test machine. The initial residual stress distribution was measured with the X ray diffraction method and then embedded in the finite element model. The results show that strain-hardening behavior can significantly improve the shakedown performance, and the larger the hardening modulus is, the less the maximum plastic strain is at the final shakedown state. Initial residual compressive stress is helpful to improve the shakedown performance, while initial residual tensile stress has negative influence on the shakedown performance. As the normal load increases, the influence of the initial residual stress on the shakedown state becomes weakened.

NMAAP1 Expressed in BCG-Activated Macrophage Promotes M1 Macrophage Polarization

Liu, Qihui,Tian, Yuan,Zhao, Xiangfeng,Jing, Haifeng,Xie, Qi,Li, Peng,Li, Dong,Yan, Dongmei,Zhu, Xun Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.10

Macrophages are divided into two subpopulations: classically activated macrophages (M1) and alternatively activated macrophages (M2). BCG (Bacilli Calmette-$Gu{\acute{e}}rin$) activates disabled $na{\ddot{i}}ve$ macrophages to M1 macrophages, which act as inflammatory, microbicidal and tumoricidal cells through cell-cell contact and/or the release of soluble factors. Various transcription factors and signaling pathways are involved in the regulation of macrophage activation and polarization. We discovered that BCG-activated macrophages (BAM) expressed a new molecule, and we named it Novel Macrophage Activated Associated Protein 1 (NMAAP1). 1 The current study found that the overexpression of NMAAP1 in macrophages results in M1 polarization with increased expression levels of M1 genes, such as inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-${\alpha}$), Interleukin 6 (IL-6), Interleukin 12 (IL-12), Monocyte chemoattractant protein-1 (MCP-1) and Interleukin-1 beta (IL-$1{\beta}$), and decreased expression of some M2 genes, such as Kruppel-like factor 4 (KLF4) and suppressor of cytokine signaling 1 (SOCS1), but not other M2 genes, including arginase-1 (Arg-1), Interleukin (IL-10), transforming growth factor beta (TGF-${\beta}$) and found in inflammatory zone 1 (Fizz1). Moreover, NMAAP1 overexpression in the RAW264.7 cell line increased cytotoxicity against MCA207 tumor cells, which depends on increased inflammatory cytokines rather than cell-cell contact. NMAAP1 also substantially enhanced the phagocytic ability of macrophages, which implies that NMAAP1 promoted macrophage adhesive and clearance activities. Our results indicate that NMAAP1 is an essential molecule that modulates macrophages phenotype and plays an important role in macrophage tumoricidal functions.

NMAAP1 Expressed in BCG-Activated Macrophage Promotes M1 Macrophage Polarization

Qihui Liu,Xun Zhu,Yuan Tian,Xiangfeng Zhao,Haifeng Jing,Qi Xie,Peng Li,Dong Li,Dongmei Yan 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.10

Macrophages are divided into two subpopulations: classically activated macrophages (M1) and alternatively activated macrophages (M2). BCG (Bacilli Calmette-Guérin) activates disabled naïve macrophages to M1 macrophages, which act as inflammatory, microbicidal and tumoricidal cells through cell-cell contact and/or the release of soluble factors. Various transcription factors and signaling pathways are involved in the regulation of macrophage activation and polarization. We discovered that BCG-activated macrophages (BAM) expressed a new molecule, and we named it Novel Macrophage Activated Associated Protein 1 (NMAAP1). 1 The current study found that the overexpression of NMAAP1 in macrophages results in M1 polarization with increased expression levels of M1 genes, such as inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), Interleukin 6 (IL-6), Interleukin 12 (IL-12), Monocyte chemoattractant protein-1 (MCP-1) and Interleukin-1 beta (IL-1β), and decreased expression of some M2 genes, such as Kruppel-like factor 4 (KLF4) and suppressor of cytokine signaling 1 (SOCS1), but not other M2 genes, including arginase-1 (Arg-1), Interleukin (IL-10), transforming growth factor beta (TGF-β) and found in inflammatory zone 1 (Fizz1). Moreover, NMAAP1 overexpression in the RAW264.7 cell line increased cytotoxicity against MCA207 tumor cells, which depends on increased inflammatory cytokines rather than cell-cell contact. NMAAP1 also substantially enhanced the phagocytic ability of macrophages, which implies that NMAAP1 promoted macrophage adhesive and clearance activities. Our results indicate that NMAAP1 is an essential molecule that modulates macrophages phenotype and plays an important role in macrophage tumoricidal functions.

Comparison of Unilateral Biportal Endoscopy Decompression and Microscopic Decompression Effectiveness in Lumbar Spinal Stenosis Treatment: A Systematic Review and Meta-analysis

Junjie Li,Jiheng Yin,Jun Liu,haixiong Lin,Haifeng Yuan 대한척추외과학회 2023 Asian Spine Journal Vol.17 No.2

This study aimed to compare the safety and effectiveness between unilateral biportal endoscopy (UBE) technique and microscopic decompression (MD) technique in lumbar spinal stenosis treatment. PubMed, Cochrane Library, Embase, Web of Science, China National Knowledge Infrastructure, and other databases were used to conduct extensive literature searches. RevMan ver. 5.3 software was used for the statistical analysis. Eleven studies were included with 930 patients, including 449 patients in the UBE group and 521 in the MD group. Both techniques revealed similar operative times at −1.77 minutes (95% confidence interval [CI], −7.59 to 4.05 minutes; p =0.55), the postoperative dural expansion area at −1.27 (95% CI, −19.30 to 16.77; p =0.89), the postoperative complications at 0.76 (95% CI, 0.47 to 1.22; p =0.26), the preoperative Visual Analog Scale (VAS) for leg pain, and the last follow-up (>12 months) VAS for leg pain at −0.04 (95% CI, −0.14 to 0.06; p =0.47), the preoperative Oswestry Disability Index (ODI), and the last follow-up (>12 months) ODI scores at −0.18 (95% CI, −0.76 to 0.40; p =0.54), and patient satisfaction (the modified MacNab score) at 1.15 (95% CI, 0.54 to 2.42; p =0.72). However, intraoperative bleeding was lower following the UBE technique at −52.78 mL (95% CI, −93.47 to −12.08 mL; p =0.01) and was shorter following the UBE technique at −3.06 (95% CI, −3.84 to −2.28; p <0.01). UBE and MD technology have no significant differences in efficacy or safety in the treatment of patients with lumbar spinal stenosis based on this meta-analysis. However, the UBE technique has less intraoperative bleeding and a shorter hospital stay. It has a slight advantage and is a better surgical option than the MD technique. It can be an alternative minimally invasive spinal surgery method.

Giant Electron-Phonon Coupling and Deep Conduction Band Resonance in Metal Halide Double Perovskite

Steele, Julian A.,Puech, Pascal,Keshavarz, Masoumeh,Yang, Ruoxi,Banerjee, Subhasree,Debroye, Elke,Kim, Cheol Woong,Yuan, Haifeng,Heo, Nam Ho,Vanacken, Johan,Walsh, Aron,Hofkens, Johan,Roeffaers, Maart American Chemical Society 2018 ACS NANO Vol.12 No.8

<P>The room-temperature charge carrier mobility and excitation-emission properties of metal halide perovskites are governed by their electronic band structures and intrinsic lattice phonon scattering mechanisms. Establishing how charge carriers interact within this scenario will have far-reaching consequences for developing high-efficiency materials for optoelectronic applications. Herein we evaluate the charge carrier scattering properties and conduction band environment of the double perovskite Cs<SUB>2</SUB>AgBiBr<SUB>6</SUB><I>via</I> a combinatorial approach; single crystal X-ray diffraction, optical excitation and temperature-dependent emission spectroscopy, resonant and nonresonant Raman scattering, further supported by first-principles calculations. We identify deep conduction band energy levels and that scattering from longitudinal optical phonons-<I>via</I> the Fröhlich interaction-dominates electron scattering at room temperature, manifesting within the nominally nonresonant Raman spectrum as multiphonon processes up to the fourth order. A Fröhlich coupling constant nearing 230 meV is inferred from a temperature-dependent emission line width analysis and is found to be extremely large compared to popular lead halide perovskites (between 40 and 60 meV), highlighting the fundamentally different nature of the two “single” and “double” perovskite materials branches.</P> [FIG OMISSION]</BR>