On the uniform consistency of frequency polygons for ψ-mixing samples

Guo-dong Xing,Shan-chao Yang,Xin Liang 한국통계학회 2015 Journal of the Korean Statistical Society Vol.44 No.2

In this article, the frequency polygon investigated by Scott (1985) is studied as a nonparametric estimator for ψ-mixing samples. Under mild conditions, we prove the uniformly strong consistency of the estimator and obtain the corresponding rate of convergence which is nearly equal to the one obtained by Carbon et al. (1997) and, our results weaken the relevant conditions used by Carbon et al. (1997). In addition, the uniformly weak consistency is also given.

A dynamic asymmetrical crack model of bridging fiber pull-out in unidirectional composite materials

Xin-gang Li,Yun-hong Cheng,Nian-chun Lü,Guo-dong Hao,Jin Cheng 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.9

As a rule, when a crack happens in composite materials, the fibrous system will generate bridging fibers resulted in the asymmetrical extending of the crack. In this paper, a dynamic asymmetrical crack model of bridging fiber pull-out in unidirectional composite materials is built for analyzing the distributions stress and displacement with the internal asymmetrical crack under the loading conditions of an applied non- stress and the traction forces on crack faces yielded by the bridging fiber pull-out model. Thus the fiber failure is determined by the maximum tensile stress, the fiber ruptures, and hence the crack propagation should also occur in self-similar modality. The formulation involves the development of a Riemann-Hilbert problem. The analytical solution of an asymmetrical extension crack in unidirectional composite materials under the conditions of moving increasing loads Pt²/x² and Px²/t is concluded, respectively. Based on relative material properties, the variable law of dynamic stress intensity factors was depicted perfectly. After the conclusion of analytical solutions with the superposition theorem, the solutions of arbitrary complex problems could be acquired.

Chemosensitizing effect and mechanism of imperatorin on the anti-tumor activity of doxorubicin in tumor cells and transplantation tumor model

Xin-li Liang,Miao-miao Ji,Zheng-gen Liao,Guo-wei Zhao,Xi-lan Tang,Wei Dong 대한약리학회 2022 The Korean Journal of Physiology & Pharmacology Vol.26 No.3

Multidrug resistance of tumors has been a severe obstacle to the success of cancer chemotherapy. The study wants to investigate the reversal effects of imperatorin (IMP) on doxorubicin (DOX) resistance in K562/DOX leukemia cells, A2780/Taxol cells and in NOD/SCID mice, to explore the possible molecular mechanisms. K562/ DOX and A2780/Taxol cells were treated with various concentrations of DOX and Taol with or without different concentrations of IMP, respectively. K562/DOX xenograft model was used to assess anti-tumor effect of IMP combined with DOX. MTT assay, Rhodamine 123 efflux assay, RT-PCR, and Western blot analysis were determined in vivo and in vitro. Results showed that IMP significantly enhanced the cytotoxicity of DOX and Taxol toward corresponding resistance cells. In vivo results illustrated both the tumor volume and tumor weight were significantly decreased after 2-week treatment with IMP combined with DOX compared to the DOX alone group. Western blotting and RT-PCR analyses indicated that IMP downregulated the expression of P-gp in K562/DOX xenograft tumors in NOD/SCID mice. We also evaluated glycolysis and glutamine metabolism in K562/DOX cells by measuring glucose consumption and lactate production. The results revealed that IMP could significantly reduce the glucose consumption and lactate production of K562/DOX cells. Furthermore, IMP could also remarkably repress the glutamine consumption, α-KG and ATP production of K562/DOX cells. Thus, IMP may sensitize K562/DOX cells to DOX and enhance the antitumor effect of DOX in K562/DOX xenograft tumors in NOD/SCID mice. IMP may be an adjuvant therapy to mitigate the multidrug resistance in leukemia chemotherapy.

Changes in Arbuscular Mycorrhizal Fungus Community Along an Exotic Plant Eupatorium adenophorum Invasion in a Chinese Secondary Forest

Xin Sun,Cheng Gao,Liang-Dong Guo 한국미생물학회 2013 The journal of microbiology Vol.51 No.3

Knowledge of the changes in arbuscular mycorrhizal (AM) fungi is fundamental for understanding the success of exotic plant invasions in natural ecosystems. In this study, AM fungal colonization and spore community were examined along an invasive gradient of the exotic plant Eupatorium adenophorum in a secondary forest in southwestern China. With increasing E. adenophorum invasion, the density of arbuscules in the roots of E. adenophorum significantly increased, but the AM root colonization rate and the densities of vesicles and hyphal coils in roots of E. adenophorum were not significantly different. A total of 29 AM fungi belonging to nine genera were identified based on spore morphology. Claroideoglomus etunicatum, Funneliformis geosporus, and Glomus aggregatum were the most common AM fungal species. The E. adenophorum invasion significantly decreased the AM fungal spore density in the soil. Furthermore, with increasing of E. adenophorum invasion the spore densities of C. etunicatum, G. aggregatum, and G. arenarium significantly decreased, whereas F. geosporus significantly increased. Nonmetric multidimensional scaling demonstrated that the AM fungus community composition was significantly different (P=0.003) in the different invasive levels of E. adenophorum, and significantly correlated with plant species richness, soil total P, and soil NO3--N. The results suggest that the alteration in AM fungus community might be caused by E. adenophorum invasion via changing the local plant community and soil properties in a Chinese secondary forest ecosystem.

Effect of Portal Vein Chemotherapy on Liver Metastasis after Surgical Resection of Colorectal Cancer

Yu, Dong-Sheng,Li, Ying,Huang, Xin-En,Lu, Yan-Yan,Wu, Xue-Yan,Liu, Jin,Cao, Jie,Xu, Xia,Xiang, Jin,Wang, Guo-Ping Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9

Objective: To explore the effect of portal vein chemotherapy on liver metastasis after surgical resection of colorectal cancer. Methods: Patients fulfilling the eligibility criteria were assigned to receive either surgery plus 1-week continuous infusion of 5-FU (study group) or surgery alone (observational group). Patients in the study group received portal vein chemotherapy, whereby 5-FU (1000 mg/d) and heparin (5000 IU/d) infusion was initiated from the day of surgery and lasted for 7 consecutive days. Liver metastasis was monitored during five years follow-up postoperatively. Results: Sixty four patients were recruited and assigned to the study group (12 with colon and 20 with rectal cancer) or the control group (10 with colon and 22 with rectal cancer). Liver metastasis rate was 12.5% in study and 25.0% in observational group, the difference being significant (P<0.01). Conclusion: Portal vein chemotherapy could be an effective treatment in preventing liver metastasis after surgical resection of colorectal cancer.

The Computer Control On Laser Pulse Energy In Precise Laser Machinings

Xiao Dong Wang,Kun Sun,Zhong Ming Piao,Guo Liang Yuan,De Seng Xin,Hui Dong 대한전자공학회 1991 International Conference on Electronics, Informati Vol.1 No.1

Biomechanical Role of Nucleotomy in Vibration Characteristics of Human Spine

Qing-Dong Wang,Li-Xin Guo 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.7

Nucleotomy is a common surgical procedure for the treatment of lumbar diseases. It may accelerate degeneration in the operated disc and decreased segmental stability, and this has been widely concerned by scholars for many years. However, under whole-body vibration, nucleotomy how to affect the vibration characteristics of the lumbar spine and complications is urgent to know. A three-dimensional nonlinear osteoligamentous finite element model of the intact L1-sacrum lumbar spine with muscles was established, and the nucleus of the L4–L5 disc was removed in the nucleotomy model. The lower surface of the sacrum was fully constrained for all models. A 5 Hz, 40 N sinusoidal vertical load supplemented with a 400 N preload was applied at L1 to simulate the vertical vibration of the human body. The results showed that nucleotomy increased the dynamic responses of the discs such as stress in the annulus ground substance and intradiscal pressure both in the maximum value and vibration amplitude. The maximum endplate stresses and corresponding vibration amplitudes of the denucleated L4–L5 level increased because of nucleotomy. Nucleotomy decreased the maximum response values of disc height and segmental lordosis but increased the corresponding amplitudes. Therefore, these findings imply that nucleotomy may increase the risk of developing complications such as disc degeneration, adjacent segment disease, endplate degeneration, lumbar instability, nerve root compress, isthmic spondylolisthesis, and lumbar disc herniation under whole-body vibration. This study reveals insights into the effect of the nucleotomy on the vibration characteristics of the lumbar spine and provides new information toward the relationship between nucleotomy and complications.

Biomechanical analysis of a new bilateral pedicle screw fixator system based on topological optimization

Li-Xin Guo,Qing-Dong Wang 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.7

Lumbar interbody fusion supplemented with a pedicle screw fi xator is an effective treatment for spinal instability, but traditional bilateral pedicle screw fi xator may cause some complications, such as degenerative disease of adjacent segments and stress concentration. The purpose of this study is to decrease the stiff ness of the rod by using topology optimization to alleviate the above problems. The finite element models of the intact lumbar spine, lumbar spine implanted with traditional bilateral pedicle screw fi xator (BPS) and a new fi xator designed by using topology optimization (TOD) were developed and compared. Compared with the traditional rigid rod, the volume of TOD rod was reduced by 19.8%. The results showed that the TOD model was similar to the BPS model in terms of the range of motions. TOD reduced intradiscal pressure, stresses in intervertebral discs, and facet contact forces of the adjacent segments. The TOD model significantly decreased the stress concentration region of screws and rods and reduced the stresses in pedicle screws, rods and the junction between the vertebral bodies and screws. TOD fi xator may provide a stable condition to the fusion segment as well as the BPS fi xator. What’s more, TOD alleviates the adjacent segment disease and lower the risk of screw breakage, rod breakage, and vertebral damage. The new rod designed by topology optimization might also be useful in alleviating adjacent segment disease, stress concentration and stress shielding eff ect.

Immune Reconstitution of CD4⁺T Cells after Allogeneic Hematopoietic Stem Cell Transplantation and its Correlation with Invasive Fungal Infection in Patients with Hematological Malignancies

Peng, Xin-Guo,Dong, Yan,Zhang, Ting-Ting,Wang, Kai,Ma, Yin-Jian Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

Objective: To explore the immune reconstitution of $CD4^+T$ cells after allogeneic hematopoietic stem cell transplantation (Allo-HSCT) and its relationship with invasive fungal infection (IFI) in patients with hematological malignancies. Materials and Methods: Forty-seven patients with hematological malignancies undergoing Allo-HSCT in Binzhou Medical University Hospital from February, 2010 to October, 2014 were selected. At 1, 2 and 3 months after transplantation, the immune subpopulations and concentration of cytokines were assessed respectively using flow cytometry (FCM) and enzyme linked immunosorbent assay (ELISA). The incidence of IFI after transplantation and its correlation with immune reconstitution of $CD4^+T$ cells were investigated. Results: The number of $CD4^+T$ cells and immune subpopulations increased progressively after transplantation as time went on, but the subpopulation cell count 3 months after transplantation was still significantly lower than in the control group (p<0.01). In comparison to the control group, the levels of interleukin-6 (IL-6) and IL-10 after transplantation rose evidently (p<0.01), while that of transforming growth factor-${beta}$ (TGF-${beta}$) was decreased (p<0.01). There was no statistically significant difference level of interferon-${\gamma}$ (IFN-${\gamma}$) (p>0.05). The incidence of IFI was 19.2% (9/47), and multivariate logistic regression revealed that IFI might be related to Th17 cell count (p<0.05), instead of Th1, Th2 and Treg cell counts as well as IL-6, IL-10, TGF-${beta}$ and IFN-${\gamma}$ levels (p>0.05). Conclusions: After Allo-HSCT, the immune reconstitution of $CD4^+T$ cells is delayed and Th17 cell count decreases obviously, which may be related to occurrence of IFI.

Preparation, characterization and scale performance of scale inhibitor copolymer modification with chitosan

Xiaorui Guo,Ke Dong,Xin Zhou,Jing Qi,Yang Zhou,Dongya Yang,Fengxian Qiu 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.6

A scale inhibitor copolymer modification with chitosan was prepared from maleic anhydride, styrene sulfonic sodium, acrylic amide and chitosan. The conditions of preparing scale inhibitor were optimized. The chemical structure and thermal property were investigated. Using the static experiment method, the influences of copolymer concentration, temperature time, Ca2+ concentration, HCO3 concentration of the system on the inhibition efficiency were investigated. The experimental results showed that the polymer was excellent calcium carbonate scale inhibition and the resistance rate of calcium carbonate scale up to 95.62%, and could be used in the system of high temperature and high hardness water.