Bioactive Materials, Vol 6, Iss 3, Pp 880-889 (2021)
Atherosclerosis, Sirolimus, Paclitaxel, Hypoxia, HIF-1α, Glycolysis, Materials of engineering and construction. Mechanics of materials, TA401-492, Biology (General), and QH301-705.5
Compared with paclitaxel, sirolimus has been more used in the treatment of vascular restenosis gradually as an anti-proliferative drug, but few basic studies have elucidated its mechanism. The anti-proliferative effects of sirolimus or paclitaxel have been demonstrated by numerous studies under normoxia, but few studies have been achieved focusing hypoxia. In this study, porcine carotid artery injury model and classical cobalt chloride hypoxia cell model were established. Sirolimus nanoparticles (SRM-NPs), paclitaxel nanoparticles (PTX-NPs) and blank nanoparticles (Blank-NPs) were prepared respectively. The effect of RPM-NPs on the degree of stenosis, proliferative index and the expression of PCNA after 28 days of porcine carotid artery injury model was evaluated. Compared with saline group and SRM groups, SRM-NPs group suppressed vascular stenosis, proliferative index and the expression of PCNA (P
AIP Advances, Vol 10, Iss 12, Pp 125318-125318-16 (2020)
Physics and QC1-999
A strategy of the combination of Computational Fluid Dynamics (CFD) and Building Information Model (BIM) technology was proposed to evaluate the wind environment around a building with complex façades for green building assessment. The Science and Education Building located at the Emerald Lake Campus of the Hefei University of Technology in China was selected as a case study. Two modeling methods, refined modeling by BIM software (BIM model) and traditional simplified modeling by computer aided design software (simplified model, referred to as SM model), were considered. The differences between the CFD results from the two geometry models were carefully examined. Three typical outdoor activity areas were selected to study the wind velocity difference, including the central channel, roof garden, and overhead corridor. The pressure difference between the CFD simulation results of the BIM model and the SM model at the exterior windows of the high-rise building was compared and analyzed. The results show that when a narrow channel is formed between two buildings, the wind velocity of the BIM model at the channel will be significantly lower than that of the SM model. The large “wall-type” components of the building roof will enhance the vortex area. The average pressure difference is greater than 0.5 Pa at the external window of building façades, accounting for up to 39.6%. The maximum pressure difference is as high as 10.13 Pa. The wind velocity difference is as high as 2.65 m/s at the central channel, 4 m/s at the roof garden, and 3.69 m/s at the overhead corridor. These differences will significantly affect the evaluation of the outdoor wind environment in green building assessment.
Cardiac fibrosis is an important pathological basis of various cardiovascular diseases. The roles of STAT6 signal in allergy, immune regulation, tumorigenesis, and renal fibrosis have been documented. However, the function and mechanism of STAT6 signal in sympathetic overactivation-induced cardiac fibrosis have not been fully elucidated. This study explores the novel role of STAT6 signal in isoproterenol (ISO)–induced cardiac fibrosis through the regulation of inflammatory response and the differentiation of macrophages from immature myeloid cells. The expression levels of STAT6, β1-adrenergic receptor (β1-AR), and inflammatory factors [interleukin α (IL-1α), IL-6, IL-18, and transforming growth factor β (TGF-β)] in CD11b+ myeloid cells were analyzed with a microarray study. The levels of IL-6 and TGF-β1 in the CD11b+ myeloid cells–derived macrophages were detected with reverse transcriptase–polymerase chain reaction (RT-PCR). STAT6–knockout (KO) and WT mice were used to establish a murine cardiac fibrosis model by ISO injection. Cardiac fibroblasts were isolated from the hearts of newborn STAT6-KO and WT mice, and STAT6 expression was measured by Western blotting and RT-PCR after ISO stimulation, while α-smooth muscle actin (α-SMA) expression was detected by immunofluorescence and immunohistochemistry staining. Cardiac function and pathological characteristics were examined by echocardiography and immunohistochemistry staining, respectively. Immunohistochemistry staining with anti-CD11b was performed to detect the infiltration of CD11b+ myeloid cells in heart tissue. Flow cytometry analysis was used to measure the percentages of CD11b+ myeloid cells and CD11b+Ly6C+ macrophages in the peripheral blood. The results showed that STAT6 was highly expressed in CD11b+ myeloid cells located in injured hearts, and STAT6 expression in cardiac fibroblasts was down-regulated after ISO treatment. STAT6 deficiency further aggravated ISO-induced increased expression of α-SMA in cardiac fibroblasts, myocardial fibrosis, and cardiac dysfunction. The activation of ISO/β1-AR signal aggravated cardiac inflammatory infiltration, promoted CD11b+ myeloid cell mobilization, and enhanced CD11b+Ly6C+/low macrophage differentiation, which was further exacerbated by STAT6 deficiency. Furthermore, β1-AR mRNA expression significantly increased in splenic CD11b+ myeloid cells compared to their bone marrow–derived controls, and STAT6 deficiency promoted β1-AR expression in an MI-induced sensitive cardiac fibrosis mouse model. The spleen-derived CD11b+ myeloid cells of STAT6-KO mice produced more IL-1α, IL-18, and TGF-β than their WT counterparts. Taken together, these results suggest that STAT6 signal plays a critical role in ISO-induced β1-AR overactivation and systemic inflammatory cascades, contributing to cardiac fibrogenesis. STAT6 should be a promising cardioprotective target against myocardial fibrosis and heart failure after β1-AR overactivation–induced myocardial injury.
Forced convection induced by mold electromagnetic stirrer (M-EMS) improves solidification structure in continuous casting of high carbon square billet, but vigorous stirring also causes macrosegregation. In this study, electromagnetic swirling flow in nozzle (EMSFN) was applied together with the M-EMS to optimize flow field and temperature distribution in the mold. The industrial test results showed that when the stirring directions of the two electromagnetic devices were opposite and the current parameter of the EMSFN device was 50 Hz, 400 A, the equiaxed crystal ratio increased 15% compared with that by using the M-EMS only, and the macrosegregation of carbon was minimized simultaneously. The investigation on the growth direction of columnar crystal indicated that in the upper part of the mold the heat transfer in different directions and the weakened forced convection were the key factors to prevent the solute element from being depleted at the edge and to reduce the centerline positive segregation in the billet.
propulsion, thermoacoustic, combustion instability, passive control, aeroacoustics, Motor vehicles. Aeronautics. Astronautics, and TL1-4050
In the present work, 3D Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations are performed to investigate the generation and mitigation mechanism of combustion-sustained thermoacoustic instabilities in a modelled swirl combustor. The effects of (1) swirling number SN, (2) inlet air flow rate Va and (3) inlet temperature Ti on the amplitudes and frequencies of swirling combustion-excited limit cycle oscillations are examined. It is found that the amplitude of acoustic fluctuations is increased with increasing SN and Va and decreased with the increase of Ti. The dominant frequency of oscillations is also found to increases with the increase of SN and Va. However, increasing Ti leads to the dominant frequency being decreased first and then increased. An alternative passive control method of installing an adjustable temperature heat exchanger on the combustion chamber wall is then proposed. Numerical results show that thermoacoustic oscillations could be excited and mitigated by setting the heat exchanger temperature to TH. Global and local Rayleigh indexes are applied to further reveal the excitation and attenuation effects on mechanisms. The present study is conducive to developing a simulation platform for thermoacoustic instabilities in swirling combustors. It also provides an alternative method to amplify or mitigate thermoacoustic oscillations.
Stem Cell Research & Therapy, Vol 11, Iss 1, Pp 1-20 (2020)
Human induced pluripotent stem cells, Cardiac differentiation, Histamine, Histamine receptor, Medicine (General), R5-920, Biochemistry, and QD415-436
Abstract Background The efficiency and quality of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are crucial for regenerative medicine, disease modeling, drug screening, and the study of the development events during cardiac specification. However, their applications have been hampered by the differentiation efficiency, poor maturation, and high interline variability. Recent studies have reported that histamine plays important roles in hematopoietic stem cell proliferation and neutrophil maturation. However, its roles in cardiovascular tissue regeneration have not been thoroughly investigated. In the current study, we identified a novel physiological function of the histamine/histamine 1 receptor (H1R) signal in regulating the differentiation of hiPSC-CMs and heart development. Methods Transgenic zebrafish model (cmlc2: mCherry) was treated with histamine and histamine receptor (HR) antagonists. Histological morphology and ultrastructure of zebrafish heart were measured. Histamine-deficient pregnant mice (HDC−/−) were treated with H1R antagonist (pyrilamine) by intragastric administration from E8.5 to E18.5. Cardiac histological morphology and ultrastructure were analyzed in neonatal mice, and cardiac function in adult mice was measured. In vitro, histamine and HR antagonists were administrated in the culture medium during hiPSC-CM differentiation at different stages. The efficiency and maturation of cardiac differentiation were evaluated. Finally, histamine-treated hiPSC-CMs were transplanted into ischemic myocardium to detect the possible therapeutic effect. Results Administration of H1R antagonist during heart development induced cardiac dysplasia in zebrafish. Furthermore, using histidine decarboxylase (HDC) knockout mice, we examined abnormal swelling of myocardial mitochondria and autophagy formation under the condition of endogenous histamine deficiency. Histamine significantly promoted myocardial differentiation from human induced pluripotent stem cells (hiPSCs) with better structure and function via a H1R-dependent signal. The activation of histamine/H1R signaling pathway augmented hiPSC-derived cardiomyocyte (hiPSC-CM) differentiation through the ERK1/2-STAT3 signaling pathway. In addition, histamine-pre-treated hiPSC-CMs were transplanted into the ischemic hearts of myocardial injured mice and exhibited better survival and myocardial protection. Conclusions Thus, these findings indicated that histamine/H1R and its downstream signals were not only involved in cardiac differentiation but also provided a better survival environment for stem cell transplanted into ischemic myocardium.
He Bai, Yunjiang Yang, Jinrong Bao, Anping Wu, Yan Qiao, Xueyuan Guo, Mingyuan Wang, Wenxian Li, Ying Liu, and Xiaowei Zhu
Royal Society Open Science, Vol 7, Iss 5 (2020)
sio2, core-shell-shell structure, rare earth phosphate, luminescence, nanoparticles, and Science
SiO2@GdPO4:Tb@SiO2 nanoparticles with core-shell-shell structure were successfully synthesized by a cheap silane coupling agent grafting method at room temperature. This method not only homogeneously coated rare-earth phosphate nanoparticles on the surface of silica spheres but also saved the use of rare-earth resources. The obtained nanoparticles consisted of SiO2 core with a diameter of approximately 210 nm, GdPO4:Tb intermediate shell with thickness of approximately 7 nm, and SiO2 outer shell with thickness of approximately 20 nm. This unique core-shell-shell structured nanoparticles exhibited strong luminescence properties compared with GdPO4:Tb nanoparticles. The core-shell-shell structured nanoparticles can effectively quench the intrinsic fluorescence of bovine serum albumin through a static quenching mode. The as-synthesized nanoparticles show great potential in biological cell imaging and cancer treatment.
Xiaowei Zhu, Kuisuo Yang, Anping Wu, He Bai, Jinrong Bao, Yan Qiao, Yunjiang Yang, Wenxian Li, and Ying Liu
Scientific Reports, Vol 9, Iss 1, Pp 1-11 (2019)
Medicine and Science
Abstract The novel submicro-spheres SiO2@LaPO4:Eu@SiO2 with core-shell-shell structures were prepared by connecting the SiO2 submicro-spheres and the rare earth ions through an organosilane HOOCC6H4N(CONH(CH2)3Si(OCH2CH3)3 (MABA-Si). The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy (IR). It is found that the intermediate shell of the submicro-spheres was composed by LaPO4:Eu nanoparticles with the size of about 4, 5–7, or 15–34 nm. A possible formation mechanism for the SiO2@LaPO4:Eu@SiO2 submicro-spheres has been proposed. The dependence of the photoluminescence intensity on the size of the LaPO4:Eu nanoparticles has been investigated. The intensity ratios of electrical dipole transition 5D0 → 7F2 to magnetic dipole transition 5D0 → 7F1 of Eu3+ ions were increased with decreasing the size of LaPO4:Eu nanoparticles. According to the Judd-Ofelt (J-O) theory, when the size of LaPO4:Eu nanoparticles was about 4, 5–7 and 15–34 nm, the calculated J-O parameter Ω2 (optical transition intensity parameter) was 2.30 × 10−20, 1.80 × 10−20 and 1.20 × 10−20, respectively. The increase of Ω2 indicates that the symmetry of Eu3+ in the LaPO4 lattice was gradually reduced. The photoluminescence intensity of the SiO2@LaPO4:Eu@SiO2 submicro-spheres was unquenched in aqueous solution even after 15 days.
2013 IEEE MTT-S International Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications (IMWS-BIO) Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications (IMWS-BIO), 2013 IEEE MTT-S International. :1-3 Dec, 2013
Mathematical Problems in Engineering, Vol 2020 (2020)
Engineering (General). Civil engineering (General), TA1-2040, Mathematics, and QA1-939
Breaking wave-induced scour is recognized as one of the major causes of coastal erosion and offshore structure failure, which involves in the full 3D water-air-sand interaction, raising a great challenge for the numerical simulation. To better understand this process, a nonlinear 3D numerical model based on the open-source CFD platform OpenFOAM® was self-developed in this study. The Navier–Stokes equations were used to compute the two-phase incompressible flow, combining with the finite volume method (FVM) to discretize calculation domain, a modified VOF method to track the free surface, and a k−ε model to closure the turbulence. The nearshore sediment transport process is reproduced in view of shear stress, suspended load, and bed load, in which the terms of shear stress and suspended load were updated by introducing volume fraction. The seabed morphology is updated based on Exner equation and implemented by dynamic mesh technique. The mass conservative sand slide algorithm was employed to avoid the incredible vary of the bed mesh. Importantly, a two-way coupling method connecting the hydrodynamic module with the beach morphodynamic module is implemented at each computation step to ensure the fluid-sediment interaction. The capabilities of this model were calibrated by laboratory data from some published references, and the advantages/disadvantages, as well as proper recommendations, were introduced. Finally, nonbreaking- and breaking wave-induced scour around the monopile, as well as breaking wave-induced beach evolution, were reproduced and discussed. This study would be significantly helpful to understand and evaluate the nearshore sediment transport.