Structural Design and Optimization of the Crossbeam of a Computer Numerical Controlled Milling-Machine Tool Using Sensitivity Theory and NSGA-II Algorithm

Xueguang Li,Chongqing Li,Penghui Li,Huizhong Hu,Xiansheng Sui 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.2

The crossbeam plays a vital role in computer numerical controlled milling machines, especially in machines with a gantry structure, as it directly influences the machining precision. In this study, a machine tool crossbeam was designed, and the modal frequency of the crossbeam was analyzed using the finite element model (FEM) analysis. In the improved structure obtained through FEM analysis, the X-type structure of the internal unit of the crossbeam was replaced by an O-type structure. The specific structure dimensions were further optimized using a neural-network algorithm and a nondominated sorting genetic algorithm. Finally, we calculated the effect of each crossbeam dimension on the mass, deformation, and frequency in a sensitivity analysis. After optimizing the crossbeam dimensions with respect to deformation, modal frequency, and mass, the structural characteristics of the original and optimized crossbeams were compared. After optimization, the mass and deformation were reduced by 7.45% and 3.08%, respectively, and the modal frequency was increased by 0.42%. These results confirm that the optimization improved the performance of the crossbeam structure.

Design and Characteristic Measurement of 8000 mm Large Aperture Integrating Sphere

Zhao Zhang,Zhi Wan,Xiansheng Li,Hongxing Liu,Jingxu Sun,Zexun Liu,Yamin Wang,Jianwei Ren,Jianyue Ren 한국광학회 2016 Current Optics and Photonics Vol.20 No.4

Integrating spheres play a central role in the radiometric calibration of remote sensors. With thedevelopment of the wide field of view (FOV) remote sensors, aperture diameters of remote sensors arebecoming larger and larger. To satisfy the radiometric calibration requirements of full FOV and fullaperture, an 8000mm diameter large aperture integrating sphere uniform source with a variable exit portwas designed and manufactured. This integrating sphere will be used for pre-launch test and radiometriccalibration of remote satellites. In this paper, optical theories were used to design the output spectralradiance. The LightTools software based on ray-tracing simulation method was used to determine the bestcombination and distribution of inner light sources. A spectral experiment was made to verify the spectralradiance design. To reduce the influence of longtime power-on, a new characteristic measurement methodwas developed to obtain the radiation characteristic of the integrating sphere, which could greatly improvethe measuring efficiency. This method could also be applied to measure other large aperture uniformsources. The obtained results indicate that the spatial uniformity is 98.35%, and the angular uniformityat center position is 98.78%.

Stem Cell-Derived Exosomes: A New Method for Reversing Skin Aging

Wu Jinyan,Wu Sai-Nan,Zhang Li-Ping,Zhao Xiansheng,Li Yue,Yang Quyang,Yuan Ruoyue,Liu Jian-Lan,Mao Hong-Ju,Zhu Ningwen 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.5

Senescence is an inevitable natural life process that involves structural and functional degeneration of tissues and organs. Recently, the process of skin aging has attracted much attention. Determining a means to delay or even reverse skin aging has become a research hotspot in medical cosmetology and anti-aging. Dysfunction in the epidermis and fibroblasts and changes in the composition and content of the extracellular matrix are common pathophysiological manifestations of skin aging. Reactive oxygen species and matrix metalloproteinases play essential roles in this process. Stem cells are pluripotent cells that possess self-replication abilities and can differentiate into multiple functional cells under certain conditions. These cells also possess a strong ability to facilitate tissue repair and regeneration. Stem cell transplantation has the potential for application in anti-aging therapy. Increasing studies have demonstrated that stem cells perform functions through paracrine processes, particularly those involving exosomes. Exosomes are nano-vesicular substances secreted by stem cells that participate in cell-to-cell communication by transporting their contents into target cells. In this chapter, the biological characteristics of exosomes were reviewed, including their effects on extracellular matrix formation, epidermal cell function, fibroblast function and antioxidation. Exosomes derived from stem cells may provide a new means to reverse skin aging.

Adipose-Derived Stem Cell Exosomes Promoted Hair Regeneration

Wu Jinyan,Yang Quyang,Wu Sainan,Yuan Ruoyue,Zhao Xiansheng,Li Yue,Wu Wenyu,Zhu Ningwen 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.4

Background: Some scholars have found that dermal papilla spheroid–derived exosomes could promote the development of hair follicles. However, whether adipose-derived stem cell exosomes (ADSC-Exos) have a similar effect on hair growth has not been determined yet. Thus, the purpose of this article was to detect whether ADSC-Exos could promote hair regeneration. Methods: Adipose-derived stem cells (ADSCs) were isolated from 6-week-old C57BL/6 mice. Then, ADSC-Exos were isolated from the ADSCs. Western blotting was used to detect specific exosome markers. The particle size and distribution of the exosomes were analyzed by NanoSight dynamic light scattering. A total of 12 nude mice were randomly divided into two groups (n = 6 each): the ADSC-Exos group and the control group. For the control group, a mixture of freshly isolated dermal cells (DCs) and epidermal cells (ECs) was grafted. For the ADSC-Exos group, a mixture of DCs, ECs, and 50 μg/ml of ADSC-Exos was grafted. Gross evaluation of the hair regeneration was carried out 2–3 weeks after the transplantation, and the graft site was harvested for histology at the third week. Results: The existence of exosomes derived from ADSCs was evidenced by CD63, ALX1, and CD9 expression. Two or three weeks after the grafting, the number of regenerated hairs in the ADSC-Exos group was higher than that in the control group (p < 0.001). Histologically, the terminal hairs were remarkable in the ADSC-Exos group, whereas the hair follicles observed in the control group were comparatively immature. The ADSC-Exos group had a higher number of regenerated follicles than the control group (p < 0.001). In addition, we found that the skin tissues in the ADSC-Exos group had higher PDGF and vascular endothelial growth factor expressions and lower transforming growth factor beta 1 levels than those in the control group. Conclusion: Our results indicated that ADSC-Exos could promote in vivo hair follicle regeneration. Background: Some scholars have found that dermal papilla spheroid–derived exosomes could promote the development of hair follicles. However, whether adipose-derived stem cell exosomes (ADSC-Exos) have a similar effect on hair growth has not been determined yet. Thus, the purpose of this article was to detect whether ADSC-Exos could promote hair regeneration. Methods: Adipose-derived stem cells (ADSCs) were isolated from 6-week-old C57BL/6 mice. Then, ADSC-Exos were isolated from the ADSCs. Western blotting was used to detect specific exosome markers. The particle size and distribution of the exosomes were analyzed by NanoSight dynamic light scattering. A total of 12 nude mice were randomly divided into two groups (n = 6 each): the ADSC-Exos group and the control group. For the control group, a mixture of freshly isolated dermal cells (DCs) and epidermal cells (ECs) was grafted. For the ADSC-Exos group, a mixture of DCs, ECs, and 50 μg/ml of ADSC-Exos was grafted. Gross evaluation of the hair regeneration was carried out 2–3 weeks after the transplantation, and the graft site was harvested for histology at the third week. Results: The existence of exosomes derived from ADSCs was evidenced by CD63, ALX1, and CD9 expression. Two or three weeks after the grafting, the number of regenerated hairs in the ADSC-Exos group was higher than that in the control group (p < 0.001). Histologically, the terminal hairs were remarkable in the ADSC-Exos group, whereas the hair follicles observed in the control group were comparatively immature. The ADSC-Exos group had a higher number of regenerated follicles than the control group (p < 0.001). In addition, we found that the skin tissues in the ADSC-Exos group had higher PDGF and vascular endothelial growth factor expressions and lower transforming growth factor beta 1 levels than those in the control group. Conclusion: Our results indicated that ADSC-Exos could promote in vivo hair follicle regeneration.